Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
persistence of virulent microorganisms and their byproducts in the root canal system , or the surrounding tissues , following initial endodontic treatment , is the main cause for treatment failure .
it has been reported that failing root canal treatments associated with periradicular pathosis frequently demonstrated fungi colonization .
the exact factors affecting the colonization of the root canal by fungi are not completely understood .
it seems that the most common predisposing factors are certain intracanal medicaments , local and systemic antibiotics , and previous unsuccessful endodontic treatment .
it has been hypothesized that the reduction of specific strains of bacteria in the root canal during endodontic treatment may allow fungi overgrowth in the low nutrient environment .
in addition , it is possible that fungi , such as c. albicans , may gain access to the root canal from the oral cavity as a result of poor asepsis during endodontic treatment procedures or because of coronal leakage .
in fact , the presence of c. albicans in root canals was found to be directly associated with its presence in the oral cavity of the same patients .
failure of initial endodontic treatment can often be treated successfully by retreatment or endodontic surgery .
elimination of the microbial flora and infected tissues as well as a complete seal of the root canal system , to prevent future recontamination , will enhance treatment success . in this
regard , mineral trioxide aggregate ( mta ) has become a popular material to seal off communications between the root canal system and the external surface of the root .
it has been mostly used as a retrograde filling material during apical surgery and as a sealant of root perforations .
however , mta is difficult to use because of its longer setting time and poor handling properties .
mta ( proroot mta , dentsply / tulsa dental , tulsa , ok ) is marketed in gray - colored and white - colored preparations ; both are 75% portland cement , 20% bismuth oxide , and 5% gypsum by weight .
recently , the use of the white - colored preparation became more popular because of esthetic considerations .
mta is a powder that consists of fine hydrophilic particles that in the presence of water , or moisture , forms a colloidal gel that solidifies to form hard cement within approximately 4 h. the principal constituents of the gray - colored formula are tricalcium oxide , tricalcium silicate , bismuth oxide , dicalcium silicate , tricalcium aluminate , tetracalcium aluminoferrite , and calcium sulfate dihydrate .
it has been reported that a fixed concentration of white - colored mta was effective against c. albicans
 in vitro for periods of up to 3 days .
it has also been shown that white - colored mta in concentration of 50 mg / ml was effective in killing c. albicans for periods of up to 3 days , whereas lower concentrations were not as effective . in another study ,
fungal growth occurred during 1-h incubation in both freshly mixed and 24-h set gray and white mta cements , whereas by increasing the incubation time , no fungal growth was observed in 24 and 72 h. it was also reported that both gray - colored and white - colored mta in concentrations of 50 mg / ml and 25 mg / ml were effective in killing c. albicans for periods up to 1 week .
lower concentrations of gray - colored mta might still be effective , whereas lower concentrations of white - colored mta might not .
however , the antifungal effect of mta on multiple strains of c. albicans over longer periods of time is less investigated .
the purpose of this study was to evaluate the antifungal action of various concentrations of white - colored mta against seven different c. albicans strains for various exposure periods using the tube dilution test .
fresh mix of white - colored mta ( pro - root mta , batch # 05002015 , dentsply / tulsa dental , tulsa , ok ) was prepared at concentrations of 100 , 50 , 25 , and 12.5 mg / ml by dilution with distilled water .
each freshly prepared mix was added to a broth tube containing sabouraud 's liquid medium ( hi - media laboratories , mumbai , india ) .
a total of 1287 broth tubes were prepared and divided into seven sets with experimental groups of 11 tubes each and control groups .
broth tubes without mta served as positive control and tubes without c. albicans served as negative control .
the antifungal action of mta against c. albicans was evaluated by using the tube dilution test .
stock cultures of six strains of c. albicans clinically isolated from the oral cavity ( strains 1 - 6 : c-89 , e-175 , c-304 , e-259 , c-176 , and e-170 ) and a standard strain ( strain 7 : microbial type culture collection ( mtcc ) 3017 ) were obtained .
fresh inoculate of the microorganism was prepared by growing overnight cultures until a complete suspension of growth was achieved .
the cultures were diluted in a pre - warmed broth to achieve a final density of 10 colony - forming unit ( cfu)/spot .
one - milliliter aliquots of the test c. albicans were taken from the broth culture and added to sterile capped test tubes of each experimental and positive control group .
all experimental and control groups were then incubated at 37c and evaluated at 1- , 24- , 72- , and 168-h ( 7 days ) time periods . at each time period
, 0.1 ml of samples from each tube was subcultured on sabouraud 's dextrose agar plates ( hi - media laboratories , mumbai , india ) .
differences among the groups were statistically analyzed using kruskal  wallis and mann  whitney u tests ( statistical package for the social sciences ( spss ) 7 software ) .
if the calculated critical values were at least as large as the respective critical values at the 0.05 level , then calculations were considered statistically significant in this study .
generally , a direct correlation was found between mta concentrations and its inhibition effect on c. albicans growth .
differing behavior patterns of various strains of c. albicans were also seen [ table 1 ] .
strains 5 , 6 , and 7 displayed intermediate resistance to mta , whereas strains 3 and 4 appeared to be most resistant .
the negative controls showed no fungal growth at any time period , whereas the positive controls always showed fungal growth .
effect of various mta concentrations on growth of c. albicans strains statistically , a significant difference was found between tubes containing either strain 3 or 4 and tubes containing other strains at all mta concentrations at the 1-day time period ( p < 0.001 ) .
a significant difference was found between tubes containing strain 3 and tubes containing other strains at mta concentrations of 12.5 and 25 mg / ml at the 3-days time period ( p < 0.001 ) .
a significant difference was also found between tubes containing 12.5 mg / ml and tubes containing higher concentrations of mta at the 7-days time period ( p < 0.001 ) .
the method used in the present study was the tube dilution test , which is an effective method to evaluate the antifungal and antibacterial properties of any filling material or solution .
it was considered appropriate for evaluating the antifungal activity of mta , which has a low solubility and diffusibility . c. albicans was the test organism in this study .
it is a frequent colonizer of the oral cavity , and multiple unrelated strains showing varying pathogenicity may be present in the same individual . mechanisms of pathogenicity of different strains may include the power of adaptability to a variety of environmental conditions attributable to the switching of gene expression dictated by environmental changes and evasion and immunomodulation of the host defenses by different mechanisms . c. albicans is frequently associated with failing root canal treatments and has the ability to form biofilms on different surfaces , which makes it more pathogenic than species that are less able to form biofilms .
as it may be involved in cases of persistent and secondary infections , usually present during apical surgery and perforation repair procedures , the antifungal action of the repair material may further assist in the management of such infections and enhance tissue healing . in this study ,
growth of seven strains of c. albicans in four concentrations of mta was assessed for periods of up to 7 days .
only one strain showed relative resistance even after 3 days at the lower mta concentration of 12.5 and 25 mg / ml .
recurrence of fungal growth was seen with three strains at mta concentration of 12.5 mg / ml after 7 days .
it might indicate that mta only exhibits a fungistatic action at lower concentrations , whereas a fungicidal action may be expected at higher concentrations .
this highlights the significance of using seven strains in the present study . in a previous study ,
al - nazhan and al - judai reported white - colored mta to be effective in killing c. albicans
 in vitro for a period of up to 3 days .
however , in that study a higher concentration of mta was used . in another in vitro study , al - hezaimi et al .
, assessed the antifungal action of different concentrations of white - colored mta against c. albicans
 in vitro .
white - colored mta in concentration of 50 mg / ml was effective in inhibiting c. albicans for periods of up to 3 days , whereas lower concentrations were not effective .
mohammadi et al . , observed fungal growth during 1-h incubation in both freshly mixed and 24-h set gray and white mta cements , whereas by increasing the incubation time , no fungal growth was observed in 24 and 72 h. another study also showed that both white and gray mta in concentrations of 50 and 25 mg / ml were effective in inhibiting c. albicans for periods of up to 7 days .
kangarlou et al . , assessed the antifungal activity of proroot mta and mta - angelus and concluded that mta - angelus was a more effective antifungal agent compared with proroot mta at concentrations of 50 and 100 mg / ml .
regarding the antifungal action of mta , it has been shown that the mechanism of action of mta involves the dissolution of calcium oxide , which increases ph by releasing ca and oh . the high ph increases the permeability of cell membranes with leakage of intracellular components .
waltimo et al . , reported that c. albicans survived incubation in calcium hydroxide solution for 1 and 6 h and was killed after 6 h of incubation .
ferguson et al . , found that an aqueous solution of calcium hydroxide had no activity against c. albicans .
however , when maintained in direct contact with c. albicans cells , calcium hydroxide paste was very effective in killing this fungus .
therefore , it can be assumed that mta is more effective in killing c. albicans when placed in direct contact with the fungus .
in addition , samiei et al . , reported that adding silver nanoparticles to mta improved its antimicrobial efficacy . in conclusion
, it appears that under the conditions of this study , white - colored mta in concentrations of 100 and 50 mg / ml is effective in inhibiting the seven tested strains of c. albicans for periods up to 1 week .
however , the antifungal activity of white - colored and gray - colored mta over longer periods of time on more number of strains merits further investigation .

Answer:
aim : the purpose of this study was to evaluate the antifungal action of various concentrations of white mineral trioxide aggregate ( mta ) against seven different strains of candida albicans using the tube dilution test.materials and methods : fresh mix of mta was prepared at concentrations of 100 , 50 , 25 , and 12.5 mg / ml and added to a broth tube containing sabouraud 's liquid medium .
 a total of 1287 broth tubes were prepared and divided into experimental and control groups .
 stock cultures of seven strains of c. albicans were obtained .
 fresh inoculate of the microorganism was prepared by growing overnight cultures .
 aliquots of the test c. albicans were taken and added to the test tubes .
 all tubes were incubated at 37c for 1- , 24- , 72- , and 168-h time periods . at each time period , the presence of c. albicans colonies was assessed.statistical analysis used : differences among the groups were statistically analyzed using kruskal  wallis and mann  whitney u tests.results:results showed that one strain showed resistance even after 3 days at the lower mta concentrations of 12.5 and 25 mg / ml . growth reoccurred with three strains at mta concentration of 12.5 mg / ml after 7 days .
 a significant difference was found between strain 3 and other strains at mta concentrations of 12.5 and 25 mg / ml at the 3-days time period and between tubes containing 12.5 mg / ml and tubes containing higher concentrations of mta at the 7-days time period.conclusion:white mta in concentrations of 100 and 50 mg / ml is effective in inhibiting the seven tested strains of c. albicans for periods up to 1 week .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
a 65-year - old man without any symptoms was referred for an operation on the aortic root and ascending aortic aneurysm .
he had undergone a total correction of tetralogy of fallot ( tof ) and aortic valve replacement with mechanical valvular prosthesis 22 years earlier ( in 1987 , at the age of forty - three ) . in august 2009 ,
a huge aneurysmal dilatation ( 9 cm ) of aortic root and proximal ascending aorta , severe tricuspid regurgitation , and good left ventricular ejection fraction were found on echocardiography .
computed tomography showed a huge saccular aneurysm of the aortic root and proximal ascending thoracic aorta ( fig .
1 ) . the patient underwent a bentall procedure involving a composite conduit with a mechanical valvular prosthesis .
the operation also included pulmonary valve replacement using a bioprosthesis , tricuspid annuloplasty , subaortic pannus resection , maze procedure , and coronary artery bypass surgery ( saphenous vein to proximal right coronary artery ) .
because the right coronary artery orifice was deviated to the left side and was close to the aortic annulus , coronary artery bypass surgery was chosen despite availability of the button technique .
after the operation , there was the microscopic finding of cystic medial degeneration in the ascending aortic wall ( fig .
he was discharged on his 37th postoperative day . at follow - up , he remains well 17 months after this latest procedure .
in 1997 , dodds and colleagues described the first series report about progressive aortic regurgitation and aortic root dilatation after complete , uncomplicated repair of tof .
a long - standing volume overload of the aortic root may cause aortic root dilatation in adults with a repaired tof .
the right to left shunt through the ventricular septal defect in unrepaired tof increases the volume overload effect on the aortic root . another causative mechanism for progressive aortic root dilatation
intrinsic histological changes were found in tof patients ; including medionecrosis , fibrosis , cystic medial necrosis , elastic fragmentation and elastic lamellae disruption .
our patient had initial reparative surgery at the age of forty - three in 1987 .
the phrase of the enlarged aorta was described in the record of the first operation .
, we did not know why correction was not performed in the initial operation . in 2002 ,
an operation for ascending aortic aneurysm was recommended , but he refused any surgery at that time .
the pathologic conditions of aortic root and ascending aorta in repaired tof are no longer a benign problem . in recent reports ,
these are the first reports of aortic dissection in tetralogy of fallot . after an initial curative operation for tof , meticulous monitoring of aortic root and ascending

Answer:
surgical repair of the tetralogy of fallot is one of the most successful operations in the treatment of congenital heart diseases .
 we report the case of a 65-year - old man who had an aortic valve replacement at the time of complete repair of the tetralogy of fallot at the age of forty - three .
 he subsequently had progressive aortic root and ascending aorta dilation to 9 cm .
 the aortic root and ascending aorta replacement was done using a composite valve - graft and was performed along with other procedures .
 thus , meticulous follow - up of aortic root and ascending aorta after corrective surgery for tetralogy of fallot is recommended following initial curative surgery .


Question:
You will be shown the title of a chemistry paper, together with sections excerpted from the body of the paper. The paper sections may include HTML tags like `<p>` and `</p>`; please ignore these. Your task is to write an abstract for the paper. Your response should include the abstract and no other text.

Title:
The development of a dedicated polymer support for the solid-phase oligosaccharide synthesis\xe2\x80\xa0

Paper sections:

With the advances in the field of glycosciences and an increasing number of structures elucidated and applied in all areas of the field, the need for reliable approaches to the synthesis of glycans has grown exponentially.1 Traditional glycan synthesis in solution involves iteration of glycosylation and deprotection steps with interim purification for practically every intermediate. Some advanced strategies based on either chemoselective or selective activation of building blocks help to streamline the oligosaccharide assembly significantly.2 However, no universal route to the chemical synthesis of glycans can be established, which dramatically hinders progress in glycosciences, whereas other biopolymers, peptides3,4 and oligonucleotides,5 can be produced by machines. Solid-phase synthesis eliminates the need for conventional reaction work-up and purification of intermediates,6–8 and offers promising automation amenability. Since early efforts in 2001,9 Seeberger et al. developed a dedicated automated oligosaccharide synthesizer in 201210 that was later commercialized as Glyconeer 2.1.11

Also in 2012, we reported High Performance Liquid Chromatography equipment-based Automation (HPLC-A) of solid-phase synthesis.12 The general idea for developing the HPLC-A is that a computer interface coupled with standard HPLC components will allow recording a successful automated sequence as a computer program that can then be reproduced with the "press of a button."

However, solid-phase synthesis of glycans suffers from certain inherent weaknesses. "The chemistry and biology of carbohydrates has been a Cinderella field,"13 and the area of solid-phase synthesis wherein everything has been "borrowed" from other fields illustrates this problem very clearly. For example, instead of developing dedicated supports, commercial resins designed specifically for peptide or nucleotide solid-phase synthesis14–16 are meticulously evaluated to determine their possible suitability for glycan synthesis, which often demands different characteristics.17 While HPLC-A and other automated approaches have a potential to revolutionize the way glycan synthesis is conducted, all current platforms suffer from inherent weakness of solid-phase synthesis as applied to glycans, among which is poor compatibility of existing commercial resins. Reported herein is the first step of our strategic goal to tackle all key weaknesses of the solid-phase synthesis, both automated and manual.

All traditional resins are based on polystyrene, but differ in functionalization/crosslinking, albeit none were designed specifically with the solid-phase synthesis of glycans in mind.18 Seeberger automation platform relies on the Merrifield resin. Our original HPLC-A set-up was based on Tentagel, a polystyrene grafted with PEG chains.12 Later on, we identified JandaJel polystyrene resin crosslinked with tetrahydrofuran-derived chains as a more suitable support for HPLC-A19 due to its better swelling properties compared to the traditional Merrifield resin. Cross-linked polystyrenes are mechanically stable and can be obtained on a large scale from broadly available and inexpensive precursors. However, phenol-based cross-linking used in JandaJel (1, Fig. 1) may potentially have marginal stability under strongly (Lewis) acidic conditions, such as large amounts of trimethylsilyl trifluoromethanesulfonate (TMSOTf)20 commonly employed in the solid-phase synthesis of glycans.

Although this degradation was not thought to significantly hinder general progress, we came to the realization that beads designed for peptides do not have the necessary properties suitable for glycan solid-phase synthesis. Researchers working with polymer-supported glycan synthesis often encounter limited swelling, marginal chemical stability, resin poisoning, reagent trapping, etc. To address this potential weakness, described herein is the investigation of benzyl alcohol-derived ethylene glycol chain cross-linking (2, Fig. 1) due to the anticipated greater stability of such structures under (strongly) acidic reaction conditions.21,22 This type of resin was first synthesized by Itsuno et al.,22 but its application in solid-phase synthesis is unknown. Interestingly, benzylic attachments have been considered by Janda and co-workers,23,24 but were deemed inferior due to their marginal stability toward strongly basic reagents, such as BuLi. To increase the swelling properties in polar protic solvents, we chose to replace the tetrahydrofuran chain used by Janda with diethylene glycol (DEG) derived structure 2 depicted in Fig. 1. Ethylene-glycol,25 its homologs, and other similar molecules24 have been previously investigated as crosslinkers, but the application of such resins in solid-phase synthesis is unknown.22

Crosslinked monomer 2 was synthesized using paravinylbenzyl chloride 3 and diethylene glycol 4 in the presence of NaH in DMF, affording the desired compound in a good yield of 85% (Scheme 1). The cross-linked monomer 2 was then used in the synthesis of a 2% cross-linked polymer 6. For this purpose, a mixture of monomers 2, 3, and 5 in a respective ratio of 2/10/88 (w/w/w) was polymerized in the presence of benzoyl peroxide, sodium chloride, and Arabic gum in water at 85 °C for 16 h following a procedure previously described by Janda.20 The desired polymer 6 was then purified using a Soxhlet extractor and i-PrOH. The chlorobenzyl group was further functionalized following Gabriel's synthesis protocol, wherein the chloride was displaced with phthalimide in DMF at 55 °C. The resulting phthaloyl group was then removed with hydrazine hydrate in a mixture of MeOH and chloroform. This two-step procedure produced PanzaGel 7 equipped with the primary amine functional groups (Scheme 1) with a nominal loading capacity of 1.0 mmol g−1.

Then, the swelling properties of the polymer were investigated. Swelling was measured following described procedures,26 using a syringe equipped with a sintered frit. The volume of dry resin was measured, then solvent was introduced in the syringe and the mixture was allowed to equilibrate for 1 h. After being vortexed, extra solvent was removed using another syringe. As listed in Table 1, polymer 7 has much better swelling properties when compared to the Merrifield resin, both in polar and non-polar solvents. In addition, polymer 7 showed similar swelling volumes to those reported for JandaJel.20 Notably, PanzaGel exhibits better swelling in MeOH than that of both Merrifield's resin and JandaJel.

A set of experiments was then conducted to determine physical properties of the resin. Thermal degradation properties of PanzaGel were assessed by thermogravimetric analysis (TGA). As shown in Fig. 2, the thermal decomposition of PanzaGel 7 was investigated at various temperatures. PanzaGel was found thermally stable up to 360 °C, but about 97% weight loss occurs by 460 °C. To assess the chemical stability of PanzaGel, the polymer was treated with trimethylsilyl trifluoromethanesulfonate, as this Lewis acid was found to degrade JandaJel.20 Upon treatment of 100 mg of resin with 100 μL of TMSOTf in 1.0 mL of methylene chloride for 1 h, which exceeds the typical conditions employed in chemical glycosylations using polymer supports, no decomposition was observed. The thermal decomposition temperature and the SEM images of the polymer showed no significant difference before and after the treatment with TMSOTf. PanzaGel treated with TMSOTf decomposed by about 85% upon heating to 600 °C leaving behind a residue, indicating a chemical structure unaltered by the prolonged contact with the acid.

The prepared polymer was also investigated by scanning electron microscopy. As shown in Fig. 3, polymer 7 was prepared in a shape of monospheres with an average size of 157.64 μm (average of 30 polymer beads). Nitrogen adsorption/desorption isotherm plots have been used to evaluate the pore volume (Vp) and the surface area (S) of the synthesized material. The total pore volume was calculated as 0.0033 mL g−1. The BET surface area was found to be 0.84 m2 g−1.

To evaluate synthetic applications of the novel resin, we moved on to synthesize disaccharide 8 and pentasaccharide 9 (Fig. 4). Our labs have recently achieved a full automation of the synthesis of oligosaccharides using a two-way split valve.27 Differently from our previous experimental set up involving reagent delivery with a preparative autosampler,19,27,28 herein we investigated an HPLC system equipped with an analytical autosampler instead. This module is common on HPLC systems, which would allow to broaden the scope of HPLC-A.

To accommodate this adjustment, a higher concentration of donor 11 (0.12 mmol, 7.2 equiv.) were dissolved in 2.7 mL of methylene chloride and the donor solution was split in two vials, containing 1.6 and 1.1 mL of solution, respectively. The autosampler was programmed to draw 500 μL (0.024 mmol) of donor 11 solution per injection. The autosampler was also programmed to draw 100 μL (0.025 mmol) of TMSOTf solution in methylene chloride per injection. Donor and promoter were mixed in the needle seat and injected towards the HPLC column, loaded with 50 mg of acceptor-bound resin 10 (0.0165 mmol). The activated donor is allowed to saturate the column for 1.0 min at a flow rate of 1.0 mL min−1. After that, the flow rate was lowered to 0.05 mL min−1 to maximize the time of exposure of the resin-bound glycosyl acceptor to the glycosyl donor. The flow rate was kept at the minimum level (0.05 mL min−1) for 10 min, then increased back to 1.0 mL min−1, using fresh CH2Cl2 to wash the column from the unreacted and hydrolyzed donor. This washing step is needed to prepare the resin for new injections of donor 11 and TMSOTf solutions. The same operation was repeated four additional times and the glycosylation sequence was completed by alternating washings with methylene chloride and DMF (see the ESI,† for details).

This completes the synthetic sequence needed for the synthesis of disaccharide 8. For the synthesis of pentasaccharide 9, the temporary Fmoc protecting group was removed using a 40% solution of piperidine in DMF following the glycosylation step. Three injections of the piperidine solution were performed, and the reaction was followed using the variable wavelength detector set at 301 nm. The sequence was completed by washings alternating CH2Cl2 and DMF. Last, the polystyrene resin was reacidified through injecting 100 μL of the TMSOTf solution previously used for glycosylation. The two reactions were repeated as needed to afford the target glycan 9. As previously described, the two-way split valve diverts the flow to a collection flask. The compounds are then cleaved using a 1 M solution of sodium methoxide in MeOH/MeOH/CH2Cl2 (1.5/1/1, v/v). Through a series a post-automation steps the target glycans 8 and 9 were isolated in 80% and 30% yields, respectively. Noticeably, both syntheses were conducted at room temperature and without utilizing strictly anhydrous reaction conditions or inert atmosphere.

In conclusion, PanzaGel, a new polystyrene-based resin for polymer supported glycan synthesis has been developed. The resin that was designed specifically for glycan synthesis in mind. PanzaGel incorporated best features of common polymeric supports for peptide synthesis: high stability of Merrifield resin and greater swelling JandaJel. PanzaGel has better swelling properties than used Merrifield resin and swells better in polar solvents than JandaJel. The glycan synthesis performed at the end of this study showcased how the improved polymeric support works in application to the HPLC-A. The target oligosaccharides were obtained using the HPLC-A experimental set-up containing the split valve, similar to that recently introduced by us.27 The current application makes use of a standard HPLC analytical autosampler. New programming/injection sequences were developed specifically for this modified set-up. A new solid support for oligosaccharide synthesis will increase the attractiveness of all synthetic and automated technologies, setting the ground for further improvements, which could include grafting to improve swelling in polar solvents. The synthesis of the new resin is fairly straightforward, and the length of the cross-linker and its composition can easily be varied to achieve best results in terms of swelling, mechanical and chemical stability, flow-through applicability, and loading capacity. PanzaGel can be synthesized in many shapes and dimensions: we are currently pursuing the synthesis and application of monolithic resins in a cylinder shape that are more suitable for the in-column, flow-through applications in HPLC-A.

Answer: Reported herein is the development of a novel polystyrene-based resin that we named PanzaGel. The resin was equipped with diethylene glycol-derived cross-linker with the dedicated application to polymer supported glycan synthesis in mind. After investigating its swelling properties and obtaining encouraging data for its chemical and thermal stability we accessed the amenability of PanzaGel to the HPLC-based platform for the automated synthesis. Comparable glycosylation results to those with traditional supports have been obtained in the synthesis of glycans up to pentasaccharide that was obtained in 30% overall yield. The automated synthesis set-up implemented a common analytical autosampler for delivering all reagents for all steps of the glycan synthesis and cleavage.


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
  pulmonary hypertension is an increasingly recognized complication of sickle - cell anaemia and a risk factor for early death [ 14 ] .
recurrent episodes of acute and subacute pulmonary crises reflecting in situ sickling within the lung has been postulated to be the primary event leading to pulmonary hypertension .
haemolysis may participate in its pathogenesis by limiting nitric oxide ( no ) bioavailability and producing vasculopathy [ 5 , 6 ] .
an initial study in howard university , usa , using echocardiographic assessment of tricuspid valve regurgitant jet velocity 2.5  m / sec as diagnostic criteria , demonstrated pulmonary hypertension in 32% of adult sickle - cell patients , and the prevalence appeared to increase with age of the patients . in patients
between 40 and 49 years old , the prevalence was 40% and increased to 5560% by age 50 and above .
other studies have documented prevalence rates between 20 and 40% [ 4 , 810 ] .
sickle - cell anaemia patients with pulmonary hypertension have a significantly increased mortality rate compared with patients without pulmonary hypertension .
sutton and colleagues   reported 40% mortality rate in sickle - cell patients with pulmonary hypertension at 22 months after diagnosis ( odd ratio 7.86 ; 95% confidence interval = 2.6323.4 ) compared with sickle - cell patients without pulmonary hypertension .
castro et al .   in a study of 34 adult sickle - cell patients who underwent right heart catheterization for evaluation of pulmonary hypertension found increased pulmonary artery pressure in 20 ( 58.8% ) on initial catheterization . during 2345 months of
follow up , 11 of these 20 ( 55.0% ) died compared with 3 of the 14 without pulmonary hypertension ( 21.0% ) .
every 10  mmhg increase in mean pulmonary artery pressure was associated with 1.7 increase in mortality ( 95% confidence interval = 1.12.7 ; cox proportional hazard model , p = 0.028 ) .
the study was aimed at comparing the clinical and electrocardiographic findings in sickle - cell anaemia patients with raised pulmonary artery pressure with those of patients without pulmonary hypertension .
the study was carried out in the adult outpatient sickle - cell clinic and the cardiac centre of the university of nigeria teaching hospital ( unth ) , enugu , nigeria .
the study subjects were drawn from adult patients ( age  18 years ) , attending the adult sickle - cell clinic of the hospital , who had haemoglobin genotype ss on haemoglobin electrophoresis , were in steady state , and consented to participate in the study .
steady state is defined as absence of any crisis in the preceding four weeks , absence of any symptoms , or signs attributable to acute illness .
a total of sixty two sickle - cell anaemia patients , and sixty two age- and sex - matched normal controls were studied .
resting 12-lead electrocardiography was performed on all subjects using cardioline ar-600 model electrocardiography machine at a paper speed of 25  mm / s and standardized at 0.1  mv / mm . a single observer analyzed the electrocardiogram .
measurements of the heart rate , cardiac axis , pr- interval , qrs duration , and qtc interval were done in the standard fashion .
heart rate correction of the qt interval was performed using bazett 's formula ( qtc = qt/  rr ) .
the dispersion of p - wave , qrs , and qtc intervals was measured manually under magnifying glass by the same observer and was taken as the difference between the maximum and minimum values of each parameter on standard 12-lead electrocardiogram . left ventricular hypertrophy on electrocardiogram was based on sokolow and lyon voltage criteria , while right ventricular hypertrophy was based on the criteria described by allenstein and mori ( dominant or tall r - waves or rs pattern in a vr , v1 , and v2 with deep s - wave in i , avl , v5 , and v6 ) .
echocardiography was done using hewlett packard sonos 2500 echocardiography machine with 3.7  mhz transducer .
pulmonary artery flow acceleration time was obtained from a doppler signal of the pulmonary flow in the parasternal short - axis view at the aortic valve level and was described as the time from onset to peak flow velocity . the mean pulmonary artery pressure ( mean pap )
was calculated from the formula :   mean pap ( m
 m / h
 g ) = 90  ( 0.62  a
 t ) , where at is the acceleration time of the pulmonary artery flow .
pulmonary hypertension was defined as calculated mean pulmonary artery pressure  30  mm / hg [ 4 , 7 ] .
ethical clearance for the study was obtained from the ethical committee of the university of nigeria teaching hospital , enugu , nigeria .
the declaration of helsinki 's recommendations for guiding physicians in biomedical research involving human subjects were followed .
data were presented as means  standard deviation for continuous variables and as proportions for categorical variables
. comparisons of continuous variables between groups were made with independent student 's t - test .
for discrete variables , distribution between groups was compared with chi - square test and fishers exact test as appropriate ( where an expected cell is less than 5 ) .
multivariate pearson 's correlation coefficient was used to determine the relations between clinical , electrocardiographic data and mean pulmonary artery pressure .
all statistical analyses were carried out using the statistical packages for social sciences ( spss inc . ,
chicago , illinois ) software version 11.0 and epi - info version 3.4 . statistical tests with 2-tailed probability values less than 0.05 were considered statistically significant .
the age , gender , and anthropometric parameters of the patients and controls are shown in tables 1 and 2 .
values for pulmonary artery pressure in the patients and controls are shown in table 3 .
elevated pulmonary artery pressures ( pap ) as defined by pap  30  mmhg was demonstrated in ( 26 ) 41.9% of patients with sickle - cell anaemia and in ( 2 ) 3.2% of the controls ;
  = 26.571 , df = 1 , p < 0.001 ( figure 1 ) .
p - wave duration , qtc interval , and qtc dispersion were increased in patients with pulmonary hypertension ( table 5 ) .
significant correlation was found between mean pap and ( 1 ) frequency of crisis ( spearman correlation = 0.320 ; p = 0.011 ) , ( 2 ) body mass index ( pearson 's correlation = 0.297 ; p = 0.019 ) , and ( 3 ) qtc interval ( pearson 's correlation 0.261 ; p = 0.040 ) , ( table 6 ) .
the prevalence of pulmonary hypertension in adult nigerian sickle - cell anaemia patients in this study was 41.9% .
this value is slightly higher than previous report of 25% by aliyu et al .   in northern nigeria .
however , in that study , neither the mean pap nor the mean age of the subjects was stated .
previous studies have relied on tricuspid regurgitant jet velocity as an indirect estimate of pap .
this has resulted in an underestimation of the prevalence of pulmonary hypertension in sickle - cell anaemia patients .
results of right heart catheterization for evaluation of pulmonary artery pressures in sickle - cell patients have shown prevalence rate of 58.8% .
autopsy studies suggest that up to 75% of sickle - cell anaemia patients have histological evidence of pulmonary arterial hypertension at the time of death .
mean pap derived from the echocardiographic estimation of pulmonary artery flow acceleration time in steady - state patients as was used in this study has been shown to correlate significantly with values from cardiac catheterization .
several studies have corroborated the role of vaso - occlusive crisis and acute chest syndrome in initiating nitric oxide depletion resulting in the pathological changes in pulmonary hypertension [ 6 , 19 ] .
this study identified a positive correlation between pulmonary artery pressure and frequency of vaso - occlusive crisis .
patients with pulmonary hypertension were found to have reduced body mass index when compared with patients without pulmonary hypertension .
this difference could be due to increased disease severity in patients with pulmonary hypertension .
recurrent insitu vaso - occlusive crisis in the pulmonary vascular bed with resultant pulmonary hypertension and right ventricular hypertrophy has been demonstrated in sickle - cell disease patients .
this is in keeping with the finding by this study of a significantly increased prevalence of right ventricular hypertrophy in patients with pulmonary hypertension .
right ventricular hypertrophy in these patients explains the significant positive correlation between pulmonary artery pressure and qtc interval .
the significance of increased p - wave duration and the spatial dispersion of qtc - interval noted in this study in patients with pulmonary hypertension are unclear .
qtc dispersion is a measure of the disparity among qtc intervals in various electrocardiographic leads and reflects the variability of myocardial repolarization .
this corroborates the finding in a study by akgul et al . in turkey which recorded higher qtc dispersion in sickle - cell patients with pulmonary hypertension .
  pulmonary hypertension in adult sickle - cell anaemia patients is significantly associated with electrocardiographic evidence of right ventricular hypertrophy , increased p - wave duration , qtc interval , and qtc dispersion and correlates significantly with frequency of vaso - occlusive crisis and qtc interval .
the observations by this study tend to suggest that these parameters could be useful for early detection and prevention of pulmonary hypertension in patients with sickle - cell anaemia .

Answer:
pulmonary hypertension is an emerging complication of sickle cell anaemia with associated increased risk of mortality . in order to evaluate the clinical and electrocardiographic findings in adult sickle - cell patients with pulmonary hypertension ,
 a cross sectional study was conducted on sixty two sickle cell anaemia patients and sixty two age and sex matched normal controls .
 elevated pulmonary artery pressures ( pap ) , defined by pap  30  mm  hg on echocardiography , was demonstrated in 41.9% of patients with sickle cell anaemia and in 3.2% of the controls ;
 2 = 26.571 , p < 0.001 .
 right ventricular hypertrophy , increased p - wave duration , qtc interval , and qtc dispersion were significantly associated with pulmonary hypertension .
 significant correlation was found between mean pap and ( 1 ) frequency of crisis ( spearman correlation = 0.320 ; p = 0.011 ) , ( 2 ) body mass index ( pearson 's correlation = 0.297 ; p = 0.019 ) , and ( 3 ) qtc interval ( pearson 's correlation 0.261 ; p = 0.040 ) . pulmonary hypertension in adult sickle anaemia patients is associated with electrocardiographic evidence of right ventricular hypertrophy , and correlates significantly with frequency of vaso - occlusive crisis , and qtc interval .
 the observations by this study tend to suggest that these parameters could be useful for early detection and prevention of pulmonary hypertension in patients with sickle cell anaemia .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
discoveries of restriction enzymes by hamilton smith and daniel nathans , and reverse transcriptase by howard temin   and david baltimore   in the 1970s set the stage for an explosion in molecular and clinical genetics .
armed with a sufficient amount of the mrna product of a gene such as the beta globin gene , investigators could now produce a radioactive dna copy ( cdna ) of the mrna and use it as a valuable probe of gene expression .
cloned into an expression plasmid   and transduced into an appropriate cell , the cdna would produce mature beta globin mrna , and cdnas could be manipulated at will in what became the era of recombinant dna technology .
the new discoveries were greeted with enthusiasm by most biologists and clinical investigators but with mounting horror and suspicion by many members of the public and their elected officials , as well as some academics .
frankensteins were thought to be loose in biomedical laboratories ; monsters would be created ; plagues of vicious e. coli would be loosed on an innocent population ; mad scientists would forever contaminate the food supply ; the new genetics would lead to a resurgence of social darwinism .
the specter of nazi medicine roiled some faculty meetings and communities in which the science was rapidly advancing .
rules and restrictions were demanded that would deliberately inhibit the work . to their credit , leaders of this new genetics revolution met in asilomar california , where they established laboratory standards intended to reassure themselves , their colleagues , and the general population that gene manipulation could be rendered safe and useful .
while eager clinical investigators hoped to apply the new genetics in the treatment of inherited diseases , cooler heads recognized that the technology was not sufficiently powerful or predictable .
the more cautious advised the national institutes of health to be very wary of human application because the biological ' rules of the game ' had not yet been established .
that did not stop an american clinical entrepreneur from injecting beta globin cdna into the bone marrows of thalassemic patients in italy and israel .
his reward was failure and opprobrium , and academic medicine encountered a congress increasingly determined to surround clinical research with an ever - growing net of regulation .
how could a cdna be introduced efficiently into a rare , quiescent , mammalian cell , such as a bone marrow stem cell , remain potentially active , and be sufficiently expressed when that stem cell developed into a hematopoietic precursor and subsequently fully differentiated functional blood cell ?
furthermore , could a defective gene be actually replaced in human cells in a targeted fashion by a normal counterpart and still maintain high transcription efficiency , or would such ' plug and socket ' technology be so inefficient that correction would be impossible ?
instead , could cdnas such as a beta globin cdna be carried into the target cell chromosomes on the back of a virus , such as a retrovirus , and could the transduced sequence express its mature mrna regardless of its genomic location ?
the idea of a retrovirus as a gene - transfer agent was first seen as dangerously oncogenic , until 1983 and 1984 when mann , mulligan and baltimore   devised cell lines that would produce replication - defective retroviruses that still exploited the capacity of the viruses to incorporate themselves efficiently in the dna of dividing cells . for the most part ,
the modified retroviral vectors infected human cells at comfortingly low multiplicities of infection . shortly after this
, williams and mulligan   and dick and bernstein , and their colleagues , showed that murine bone marrow cells could be transduced with defective retroviruses carrying cdnas , and that mature nucleated blood cells would carry the foreign cdna for weeks , proving that the murine hematopoietic stem cell , despite its very low rate of division , could be so transduced .
but the percentage of infected cells was very low and expression of the transferred gene was vestigial .
the results suggested that successful gene transfer with cdnas borne on replication - defective retroviruses would require high recombinant viral titer , cell culture systems that would encourage stem cell division without differentiation , and a setting in which target cells would have a selective advantage following gene transfer .
the entire field of gene therapy was energized by the findings of williams and dick and their colleagues , but the barriers to translation and clinical application were soon found to be almost insurmountable .
the slow pace prompted orkin and motulsky   to lower their expectations for immediate clinical application , and focus instead on solving the basic technical and biological problems . in an attempt to gain some clinical traction , blaese and his colleagues   introduced retroviral cdna ex vivo into the mature t cells of patients with immunodeficiency due to mutations in adenosine deaminase .
the treatment provided little if any clinical benefit , and the risk of malignancy was obviously high because the t cells were influenced to divide in culture in order to enhance transduction .
concerns about unwieldy and potentially unsafe clinical research protocols began to mount in the united states .
four levels of review , the recombinant dna advisory committee , individual institutional review boards , individual institutional biosafety committees , and the food and drug administration all established barriers that slowed the pace of gene therapy clinical research to a crawl .
this necessary regulatory environment was onerous enough , but it became even more obstructive when investigators at the university of pennsylvania performed a study of gene replacement in a rare metabolic disorder using adenovirus as a vector in order to infect non - dividing liver cells .
one young adult with the disease died after a high titer of virus was administered .
an investigation revealed that the gene therapists had a financial stake in the company that produced the vector .
that revelation initiated an even higher burden of regulation and added massively to a growing concern about conflict of interest in clinical research - a conflict that continues to roil academic waters to this day .
meanwhile , after four decades of development , the clinical application of allogeneic hematopoietic stem cells in transplantation for the treatment of congenital bone marrow diseases was moving ahead reasonably briskly ( sans gigantic regulatory hurdles ) .
this form of cell - based therapy , though initially applicable in only the 25 - 30% of patients with histocompatible donors , was associated with success in several patients with severe immunodeficiencies , congenital bone marrow failures of several types and even the inherited hemoglobin disorders .
adenovirus vectors were thought to be too immunogenic to be useful but they and their cousin , the tiny adeno - associated virus , were considered to be worthy of evaluation in the transduction of non - dividing cells such as liver cells or endothelial cells .
indeed , high and her co - workers   have made quiet progress in the correction of canine hemophilia with adeno - associated virus .
most groups interested in hematopoietic targets or cancer vaccine protocols continue to focus on defective murine leukemia viruses or lentiviruses .
the latter are thought to have a higher capacity than murine leukemia viruses to integrate within the dna of non - dividing cells .
both the science and the regulatory apparatus seemed to be daunting , and the funding was fragmented and difficult to obtain . but in 2002 cavazzana - calvo and his colleagues   blew new life into the field when they made the startling announcement that they had successfully treated nine of ten patients with x - linked severe combined immunodeficiency ( scid ) , utilizing a fairly standard murine leukemia viral vector that carried the common gamma chain of the interleukin-2 receptor into autologous bone marrow cells .
shortly thereafter , however , cynicism returned when the authors reported that several of the patients had developed t cell leukemia .
careful work by the investigators revealed that the long terminal repeat ( ltr ) of the vector may have a predilection for the lmo2 proto - oncogene on chromosome 11 .
but even random integration of the ltr at the lmo2 site would favor selection of such cells . the lmo2 proto - oncogene is often activated by translocation ( 11:14 ) in t cell leukemia . clearly , the gene - corrected immunocytes had a survival advantage , but the malignant t cells had an even greater survival advantage as well as a growth advantage .
what was once a promising new start for gene therapy became an enormous set - back .
vector safety had always been a pressing issue - now it had become a yawning chasm : of 20 patients with x - linked scid treated by gene transfer in these two trials , 18 are currently alive and with good immune reconstitution , but five have experienced a serious side - effect .
of these five children , one died of therapy - related leukemia , and one died of complications of a subsequent stem cell transplant that was performed as a result of the failure of gene therapy .
have been the results of retroviral correction of oxidase deficiency in chronic granulomatous disease . in two well - described cases ,
correction of granulocyte oxidase deficiency has been achieved but at the cost of clonal proliferation of cells activated at the sites of the mds-1-evi1 , prdm16 or setbp1 proto - oncogenes .
furthermore , other in vitro studies have demonstrated similar insertions by lentiviruses bearing beta globin genes . finally , williams and his co - workers   have temporarily discontinued their pioneering work on the correction of the deficiency of dna repair pathways in hematopoietic stem cells of patients with fanconi anemia , because they are concerned that current vectors that permit rescue of those cells may induce insertional mutagenesis and leukemia in the treated patients , and that focus should be on developing methods of expanding deficient hematopoietic stem cells in this disease . despite these serious setbacks
there have been some recent bright lights . in 2008 , maguire   and bainbridge   and their colleagues reported progress on the treatment of leber 's optic atrophy with an adeno - associated viral vector applied to the retina . and retrovirally transfected epidermal stem cells have been grown into keratinocytes to correct the lesions of epidermolysis bullosum .
more follow - up is needed but the initial results hold promise for local applications of gene transfer .
an encouraging report emerged at a recent annual meeting of the european society of gene and cell therapy .
lentivirus vectors have been used to transduce hematopoietic stem cells in x - linked adrenoleukodystrophy , a progressive demyelinating disease that causes severe debilitation by early teenage years .
long - term and stable gene modification has been observed in 20% of myeloid cells , well within the range to reverse phenotypes in some red cell and myeloid disorders .
finally , auiti and his colleagues have recently reported highly encouraging results in the treatment of adenosine deaminase deficiency .
thus , gene therapy of hematopoietic diseases with retroviruses lumbers in choppy straits twixt the scylla of insufficient gene transfer and the charybdis of leukemia , while the therapy of metabolic and coagulation disorders with adeno- and adeno - associated viruses is blunted by immune reponses to the vectors . to committed gene therapists ,
these are simply the challenges that they have always faced , while those who are engaged in stem cell transplantation , or in finding better halfway measures that support afflicted patients , work as best they can , all the while hoping that the holy grail of gene replacement will one day become a safe reality .
the future could lie in the promising field of site - specific gene correction using modified nucleases , and the conversion of corrected somatic cells such as fibroblasts to functioning hematopoietic stem cells .
cdna : copy dna ; ltr : long terminal repeat ; scid : severe combined immunodeficiency .
the authors are particularly grateful to our colleague david a williams , md , for his contributions to this field and his invaluable assistance during the development of this review .

Answer:
though the field has moved with glacial speed , gene therapies have been carried out successfully in patients with bone marrow disorders including immune deficiencies .
 the field may be poised to move forward more rapidly , but many barriers have yet to be surmounted .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
akabane virus ( akav ) is an arthropod - borne virus belonging to the genus orthobunyavirus in the family bunyaviridae .
it causes epizootic and sporadic outbreaks of abortions , premature births , stillbirths , and congenital abnormalities characterized by arthrogryposis , hydranencephaly , or microanencephaly in cattle , sheep , and goats .
akav is widely distributed in the tropical and temperate zones in australia [ 3 , 4 ] , southeast asia , east asia [ 6 , 7 ] , the middle east , and africa .
akav infection of adult cattle causes a transient viraemia without obvious clinical signs , while infection of pregnant cattle often causes fetal damage resulting in abortion , stillbirth , or various congenital abnormalities . during 1972 to 1975 , this disease had led to the birth of more than 42,000 abnormal calves in japan , causing significant economic loss in cattle industry [ 6 , 11 ] .
subsequently , major outbreaks resulting in congenital defects in ruminants caused by akav were reported from israel , australia , taiwan , korea , and turkey [ 7 , 10 , 1215 ] . in sudan ,
akav infection was recognized based on serological evidence in sheep , goats , and cattle in various ecological zones of the country . the present study aimed at investigating the current situation of akav infection in sudan as a part of an ongoing research project on viral causes of reproductive problems of cattle in the country .
the investigation area extends from the latitudes 11 78 to 19 61 north and longitudes 22 45 to 37 21 east .
sera were collected from dairy cattle in white nile , kassala , north kordofan , sennar , blue nile , north darfur , red sea , gadarf , khartoum , and gazira states .
= 4pq / l , where n is the required number of individuals to be examined ; p is a known or estimated prevalence ; q = ( 1  p ) ; l is the allowable error .
since location to location variation was expected , the sample size was increased and all collected sera ( n = 361 ) were tested ( table 1 ) .
blood samples were collected from 361 dairy cattle in 10 states of sudan ( table 1 ) .
animal sampled included individuals with history of abortion and infertility from two states , namely , khartoum and gazira states .
animals of both sexes and various age groups ( less than 6 months , less than 1 year , 1 - 2 years , 2 - 3 years , and more than 3 years ) ; breeds ( crossbred and indigenous ) under various management systems ( extensive , semi - intensive , and intensive ) and in different seasons including dry ( march  june ) ; rainy ( july  october ) , and winter ( november  february ) were bled .
sera were extracted by centrifugation at 1,500  rpm for 10  minutes and kept at 20c until they were tested for presence of antibodies against akav using elisa .
a total of 68 out of the 361 sera samples were collected from animals suffering from reproductive problems ( infertility and abortion ) .
commercial competitive elisa antibodies kit ( i d vet innovative diagnostics , france ) was used to detect antibodies ( anti - g1 ) against akav according to manufacturer 's instructions .
the serological results and other information gathered during this investigation such as locality , sex , season , management system , signs of reproductive problem , and breed ( indigenous and crossbred ) of the sampled animals were edited and analyzed statistically using statistical package ( spss version 16 ) . to identify the association of the risk factors with the specific seroprevalence , the chi - square (  test ) was used . the statistical significance level used was p  0.05 .
the overall prevalence rate of akav antibodies found in dairy cattle samples was 29.4% ( 106/361 ) ( table 1 ) . the prevalence rate varied from highest ( 69.6% ) ( 64/92 ) in khartoum state to lowest ( 3.3% ) ( 1/30 ) in sennar state .
likewise the prevalence of akav antibodies was significantly ( p < 0.001 ) higher in crossbred animals ( 39.9% ) than in indigenous breed animals ( 8.9% ) and in females ( 33% ) than in males ( 14.3% ; p < 0.001 ) .
the prevalence rates were significantly higher in intensively ( 37% ) managed animals ( p < 0.001 ) ( table 2 ) .
the seroprevalence was significantly high among 2 - 3 years old ( 45.3 ; p < 0.001 ) and in the winter season ( 58.1% ; p < 0.001 ) .
the prevalence rates were also high in cases of infertility ( 76.2% ) and abortion ( 48.9% ) when compared to apparently healthy animals ( 22.9% ) and were significantly associated with cases of infertility ( p < 0.03 ) ( table 3 ) .
prevalence of akav antibodies in domestic ruminants in different ecological zones of sudan indicated prevalence rates of up to 27% in sheep , 36% in goats , and 47% in cattle .
the prevalence rates in cattle ranged between 10.6% and 47.8% in different areas . in the present study ,
prevalence rates of akav antibodies in dairy cattle varied greatly ranging from 3.3% in sennar state to 69.6% in khartoum state with an overall prevalence rate of 29.4% .
this higher seroprevalence in khartoum state may be due to the fact that in this state 59 cattle sera out of 92 serum samples investigated were suffering from abortion ( 39 cases ) and infertility ( 20 cases ) ( table 3 ) .
this result confirmed records of jun et al .   who discussed the associations between this virus and abortion suggesting that this virus may significantly increase abortion risk among cattle and sheep .
.   stated that transmission of akav in sudan may not be an annual event with more sporadic occurrences , a fact that may lead to variations in prevalence rates from year to year and from one area to another .
thus , while these authors recorded a prevalence rate of 10.6% for sennar state , the prevalence recorded in the present study was 3.3% for the same area .
however , both studies indicated wide geographic distribution of akav seropositivity in cattle in sudan indicating that the vector(s ) of aka virus are widespread ; unfortunately information regarding the vector(s ) in the country is lacking .
it is interesting , however , that , inspite of the observed high prevalence and wide distribution of akav infection in sudan , no evidence of outbreaks of congenital malformations , as has been reported in other parts of the world , has been recorded in dairy cattle in sudan .
the present study also revealed that prevalence rates were highly associated with locality , breed , sex , season , age of animals , and management system .
the prevalence rate was significantly higher in khartoum state ( 69.6% ; p < 0.001 ) than in other states .
animals sampled in khartoum state were from intensively managed crossbred dairy cattle that reported reproductive problems based on a questionnaire survey administered prior to collection of samples in khartoum and in gazira states .
the prevalence rates were also significantly higher in crossbred animal ( 39.9% ; p < 0.001 ) than in indigenous ones ( 8.9% ) and in females ( 33% ; p < 0.001 ) than in males which may reflect higher degree of attractiveness of these animals to insect vectors .
the prevalence rates were also higher in intensive and semi - intensive management systems ( 37.0% and 36.1% , resp . ) than in extensive systems .
the previous two systems are generally concentrated around urban areas , and crossbred animals usually constitute the majority of animals in these systems while extensive systems are usually practiced in the vast grass lands of eastern and western sudan and usually involve indigenous animals .
in addition vector arthropods may not be as numerous in the extensive system as in the intensive and semi - intensive system where microenvironmental conditions suitable for vector breeding and survival may be available year - round .
seroprevalence rates were much higher in winter season ( 58.1% ) than in dry ( 25.6% ) or rainy ( 25.3% ) season .
winter season in much of the sudan is usually very mild with an average temperature that is usually above 30c .
when examining prevalence rates of akav antibodies in individuals with reproductive problems , the results revealed that these rates were significantly higher in cases of infertility ( 76.2% ; p < 0.03 ) than in abortion cases ( 48.9% ) and were in both cases higher than in apparently healthy ( 22.9% ) animals .
however , the high prevalence rates observed in both infertility and abortion cases may indicate the importance of akav infection in the bovine reproductive syndrome in sudan warranting further investigations .
the present study clearly indicated the widespread prevalence of akav infection in dairy cattle in sudan .
absence of clinically recognized symptoms of akav infections with noticeable outbreaks of abortion and foetal malformations may lead to underestimation of the importance of the disease in the sudan .
this situation may , however , change and the disease can pose considerable threat with the increasing trend toward intensive raising of exotic breed dairy cattle to satisfy the rising local demand for milk and other dairy products . hence , further countrywide epizootiological studies of akav infections in cattle , sheep , and goats are called for to provide information required for formulating well - designed control programs .

Answer:
a cross - sectional survey was carried out in ten states in sudan to determine seroprevalence and to assess risk factors associated with akabane virus ( akav ) infection in dairy herds .
 serum samples were collected from a total of 361 dairy cattle and tested for antibodies against akav using elisa .
 the prevalence rates of akav antibodies in cattle varied between 69.6% in khartoum state and 3.3% in sennar state with an overall prevalence rate of 29.4% .
 the prevalence rates of akav antibodies were significantly associated with breed being high in crossbred ( 39.9% ; p < 0.001 ) ; female sex ( 33% ; p < 0.001 ) , and animals in the age group of 2 - 3 years old ( 45.3% ; p < 0.001 ) .
 akabane virus antibodies prevalence was also highly associated with locality ( p < 0.001 ) ; season being high in winter season ( 58.1% ; p < 0.001 ) ; and animals raised under intensive management system ( 37% ; p < 0.001 ) . among 68 cases suffering from reproductive ( abortion and infertility ) problems the prevalence rate of akav antibodies in animals with infertility problem ( 76.2% ; p <
 0.03 ) was significantly higher than in animals with abortion ( 48.9% ) .
 the study revealed that akav infection is highly prevalent in dairy cattle in sudan and this calls for control strategy to be implemented .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
for repeated administration of chemotherapeutic agents , intravenous hydration , or parenteral nutrition to cancer patients or chronically ill patients , the role of the totally implantable central venous port ( ticvp ) system is greatly increasing to address concerns about quality of life . annually , more than 5 million central catheters are implanted in the us , and the proportion of implantable catheter systems has been increasing since niederhuber et al .   first reported this system .
surgeons cut down or percutaneously puncture the cephalic , subclavian , or jugular vein , whereas interventional radiologists access the subclavian or jugular vein with the guidance of venography , ultrasound , or fluoroscopy .
recently , ultrasound - guided access to the vein , especially the internal jugular vein , and fluoroscope - guided positioning of the catheter have become widely accepted to reduce complications such as pneumothorax , pinch - off phenomenon , hematoma , or malposition of the catheter tip . however ,
because thoracic surgeons are familiar with the percutaneous puncture technique , cut down insertion of the central catheter , and the anatomy of the chest and neck vasculature , they can detect complications and manage them promptly and accurately .
they can also create a pocket port easily , given their training in pacemaker pocket creation .
in keimyung university dongsan medical center , the ticvp system has been provided by a thoracic surgeon since march 2009 .
all of the procedures were performed with one small skin incision and subcutaneous puncture of a subclavian vein . in this article , we summarize our experience of the ticvp system and present the success and complication rate of this surgical method .
the purpose of this study is to determine whether implanting a ticvp system with surgical methods is as safe as performing it with radiologic guidance .
between march 2009 and december 2010 , 245 port systems were implanted into 242 patients by thoracic surgeons .
the patients ' age , sex , underlying diseases , indications of the implantable port system , immediate and delayed complications , and total period of implantation of the port system were evaluated .
all of the study protocols were accepted by the institutional review board of keimyung university dongsan medical center . before performing the procedure , the patient 's coagulation status including prothrombin time , activated partial thromboplastin time , and platelet count were checked .
in the operating room , intravenous sedation was not performed and the patient was monitored with electrocardiography , pulse oximetry , and automatic cuff blood pressure . the neck and whole chest was prepared and draped .
a circulating nurse was positioned near the patient 's head and constantly checked the patient 's condition during the operation . as a port site ,
however , if the patient had received mastectomy or radiation therapy on the right side , or had a previous port scar , the left anterior chest was chosen .
after subcutaneous injection of 1% lidocaine for local anesthesia , a 3 cm transverse incision was made just 2 cm distal to the lower margin of the clavicle at the deltopectoral groove level .
gentle dissection of the subcutaneous tissue was done with electrocautery until the fascia layer was reached . at this layer ,
a pocket for the port was created with blunt and sharp dissection . to prevent skin tightness or necrosis , sufficient space for the port
was provided with minor bleeding control . after preparing the port site , an additional subcutaneous injection of lidocaine
an introducer needle was inserted at the deltoid tuberosity level while gently withdrawing the plunger of the syringe . because the needle was inserted through previously dissected subcutaneous tissue , no additional incision was needed .
then the needle was inserted under and along the inferior border of the clavicle , making certain that the needle was virtually horizontal to the chest wall .
once under the clavicle , the needle was advanced toward the suprasternal notch until it entered the vein .
when we failed infraclavicular subclavian vein access , we converted to a supraclavicular subclavian vein puncture just lateral to the sternocleidomastoid muscle ( fig .
1 ) . after insertion of a j - tip wire , a groshong catheter ( bardport ; bard
, salt lake , ut , usa ) was introduced through the peel off sheath .
after checking the venous return through the catheter and ensuring adequate heparinization , the catheter was cut to connect with the port ( bardport ) .
the catheter was inserted to a depth of 13 to 16 cm of the catheter length through the subcutaneous puncture site ( fig .
two anchoring sutures between the port hole and subcutaneous tissue were made to fix the port .
after checking the patency of the port and flushing it with heparin , the wound was closed with tight obliteration of the dead space to prevent hematoma . after returning from the operating room ,
a routine chest x - ray was obtained to check the catheter position and to rule out postoperative complications like pneumothorax .
a series of 245 port systems were implanted into 242 patients , including 82 men and 160 women , with an age range of 14 to 86 years ( mean , 55.74 ) . in 240 of the patients ,
the ticvp system was implanted for chemotherapy and other oncologic management , while in 2 noncancerous patients , the system was implanted for parenteral nutrition or to secure an intravenous route .
the pocket sites for the port were created on the right side of the chest wall in 203cases ( 85.3% ) . in 42 cases ( 14.7% ) , the left side of the chest wall was used due to previous scarring or wound problems in 10 , right side mastectomy in 9 , the patient 's preference for the left side in 9 , failure of right side subclavian venous puncture in 4 , pain or edema in the right arm in 4 , and other reasons in 6 .
two patients ( 0.82% ) underwent supraclavicular access of the subclavian vein after failure of infraclavicular access .
secondary insertion of the port system was performed in 6 patients , including 3 after it was surgically inserted with this method , 2 after radiology - guided insertion , and 1 inserted at another institution .
the mean operating time was 22.611.5 minutes ( range , 10 to 80 minutes ) .
accidental arterial puncture occurred in some cases , but there was no hematoma or hemothorax occurrence .
early complications within 30 days of surgery occurred in 11 patients ( 4.49% ) , including malposition of the catheter tip in 6 , malfunction of the catheter in 3 , and port site infection in 2 . among patients who experienced malposition of the catheter tip
, 2 were explanted , but the others refused to remove the catheter ( fig .
there was no evidence of venous thrombosis during their catheter indwelling . at the time of chart review ,
late complications occurred in 12 patients ( 4.90% ) including venous thrombosis in 4 , fever of unknown origin in 4 , skin necrosis in 3 , and sepsis in 1 patient .
we performed explantations in 25 patients ( 10.2% ) including 6 explantations after completion of chemotherapy . during explantation
compression of the puncture site for a while and complete obliteration of the port site dead space was performed .
the median duration of the ticvp system was 287.2 days , ranging from 3 to 980 days .
a totally implantable port system has been used increasingly since its introduction by niederhuber et al . .
the types of access vein and port site have varied according to the surgeon 's preference .
with cut down procedures , the cephalic vein or external jugular vein was preferred , while for percutaneous access , the subclavian or internal jugular vein approach was more frequently used . nowadays , to reduce perioperative complications and for accurate positioning of a catheter , ultrasound- , venography- , or fluoroscope - guided access
interventional radiologists prefer the sonographic approach using the internal jugular vein than the external landmark - guided technique [ 6 - 8 ] .
some surgeons prefer the cut down procedure to the cephalic vein instead of the percutaneous approach of the subclavian vein to avoid the risk of pneumothorax .
however , for a long period of time , the subclavian vein has been a preferred route for placement of the central venous catheter .
this route provides a lower chance of infection and good stability on the chest wall . because the left innominate vein forms an acute angle from the vena cava , and has the possibility of damaging the thoracic duct , the right subclavian vein is preferred over the left .
pneumothorax occurs at a rate of 1% to 2.5% incidence after interventional radiologic placement of the chest port [ 6 - 8 ] , while occurring at an incidence of 2.4% to 4.3% after implantation by a surgeon .
found that there was no difference in early complications among the internal jugular , subclavian , and cephalic veins in their comparison of central venous insertion sites .
they also found that ultrasound - guided subclavian insertion showed the lowest proportion of failure .
meanwhile teichgraber et al .   reported no incidence of pneumothorax after 3,160 cases with an ultrasound - guided internal jugular vein approach . in our study ,
if surgeons are very familiar with chest and neck vasculature , and have good hands with subclavian vein access , the incidence of pneumothorax will decrease .
in addition , if the needle should proceed toward the sternal notch slowly and directly without changing the axis , the chance of pneumothorax would be rare .
however , the slow and gentle advance of the needle during venipuncture , accurate checking on the venous blood return to the syringe , and rapid withdrawal of the needle after puncturing the artery can prevent these events . in our experience , even after arterial puncture , rapid removal of the puncture needle and compression of the adjacent soft tissue for 1 or 2 minutes could prevent hematoma formation in every event . in early insertion periods ( march to may , 2009 ) ,
when puncture through right subclavian access failed , the insertion site was changed to the left side . as a skin incision on the right anterior chest had already been made , an additional incision and pocket making was needed in the left side .
supraclavicular needle puncture to the subclavian vein just lateral to the sternocleidomastoid muscle was performed . with this route , the surgeon did not need to change the original patient 's right side position . when trying to access the internal jugular vein , the surgeon should change position to the patient 's head side .
two operations ( 0.82% ) were performed and no occurrence of pneumothorax with this method was observed .
lin et al .   reported their experience using external jugular vein cut down , when the cephalic vein approach failed .
below the cutdown site of the cephalic vein , they made a pocket for the port , where a new external jugular vein provided an excellent alternative route .
for secure and long - term maintenance of a ticvp system , the catheter tip position is crucial .
the united states food and drug administration has stated that the catheter tip should not be placed in or allowed to migrate into the heart . when the catheter is positioned in the right atrium
, it may cause cardiac - related complications such as perforation , tamponade , arrhythmia , or cardiac thrombosis .
furthermore , catheter tips placed in the superior vena cava ( svc ) may cause port malfunction .
many authors agree with positioning the tip at the svc - right atrial junction . on standard chest radiograph , because the upper border of the svc is at the level of the inferior border of the clavicle , or the angle of the right main bronchus and trachea , the catheter tip should be located below this level .
the svc - right atrium junction level on chest radiograph is somewhat different according to different authors .
defalque and campbell   have mentioned that the ideal tip position is between the fifth and sixth thoracic vertebrae , whereas rutherford et al
.   mentioned that it is between the right lateral margin of the svc and superior border of the cardiac silhouette , while another author described it as 1 cm inferior to the right superior cardiac border . with preliminary evaluation of the optimal catheter tip length under fluoroscopic guidance prior to the operation
, we attempted to keep the catheter length 13 to 16 cm from the subcutaneous insertion site in the operative field .
as our procedures were performed without radiologic guidance , we tried to keep the catheter tip from entering the svc area by a j - tip wire heading caudally , slowly proceeding the catheter , and checking cardiac ectopy on the monitor .
however , we found a malpositioned catheter tip located in the internal jugular or contralateral innominate vein in 6 patients ( 2.45% ) .
in this situation , we could have changed the tip position by the endovascular snaring technique or by reinsertion of the catheter in the operating room . but no patient wanted these procedures .
1 ) since all of the procedures are performed in the operating room , the risk of infection will be lower than procedures done in the angiographic suite .
2 ) because we form the pocket and perform subcutaneous cannulation of the catheter with one small skin incision , no additional incisions or subcutaneous tunneling is needed .
3 ) because the implanted catheter length is short , the risk of catheter - associated complications like lumen occlusion and infection might decrease .
however , since we did not perform a comparative study with a radiology assisted port insertion group , we have a limited ability to test these advantages . for a surgically implanted system using a subclavian vein , complication rates of 5% to 24.6%
have been reported and those radiologically implanted at the same site show a lower complication rate up to 20.7% .
however , considering the high incidence of malposition of the catheter tip , complementary cooperation with a radiologist would be needed .
surgical insertion of a ticvp system with percutaneous subclavian venous access is a safe procedure with a lower complication rate and many clinical benefits .

Answer:
backgroundthe role of totally implantable central venous port ( ticvp ) system is increasing . implantation performed by radiologist with ultrasound - guided access of vein and fluoroscope - guided positioning of catheter
 is widely accepted nowadays . in this article
 , we summarized our experience of ticvp system by surgeon and present the success and complication rate of this surgical method.materials and methodsbetween march 2009 and december 2010 , 245 ports were implanted in 242 patients by surgeon .
 these procedures were performed with one small skin incision and subcutaneous puncture of subclavian vein .
 patient 's profiles , indications of port system , early and delayed complications , and implanted period were evaluated.resultsthere were 82 men and 160 women with mean age of 55.74 . port system was implanted on right chest in 203 , and left chest in 42 patients .
 there was no intraoperative complication .
 early complications occurred in 11 patients ( 4.49% ) including malposition of catheter tip in 6 , malfunction of catheter in 3 , and port site infection in 2 .
 late complication occurred in 12 patients ( 4.90%).conclusionsurgical insertion of ticvp system with percutaneous subclavian venous access is safe procedures with lower complications .
 careful insertion of system and skilled management would decrease complication incidence .


Question:
You will be presented with the full text of a biomedical research paper. Please write an abstract for this paper. Your response should include the abstract and no additional text.

Paper text:
congenital ptosis is an abnormally low position of the upper eyelid in relation to the globe , which occurs either at birth or soon after .
there are several methods of ptosis surgery , including levator muscle resection , frontalis suspension procedure , fasanella - servat procedure , and mller muscle
conjunctival resection.1,2 one of the most popular methods of ptosis surgery is the frontalis suspension procedure .
there are various materials available to secure the lids to the frontalis muscles in the frontalis suspension procedure , including polypropylene suture , nylon suture , silicone , mersilene mesh , and gore - tex material.3 we are reporting a rare case of infected gore - tex material that was used in modified frontalis sling surgery for congenital ptosis .
a 7-year - old chinese boy with no known medical history , presented with history of right eye ptosis since he was 10 months old .
he had a marginal reflex distance of 1 mm , with levator function of 3 mm in the right eye .
the marginal reflex distance of the left eye was 2 mm , with 7 mm levator function .
he underwent ptosis surgery on the right eye as he developed mild amblyopia in the right eye , with the best - corrected vision of 6/12 . a right eye frontalis sling procedure with modified fox s pentagon method4
chloramphenicol ointment was applied 8-hourly to the surgical wound site on the right upper eyelid .
the patient was discharged on day 1 postoperation , with plan to review after 1 week .
however , he defaulted his follow - up and only came back 1 month after surgery .
he had used his medication for only 1 week and had stopped thereafter . at this presentation , he complained of painful swelling ( of 7 days duration ) of the right upper eyelid .
the right upper eyelid swelling was associated with pus discharge from the surgical wound site .
his best - corrected visual acuity was 6/12 in the right eye and 6/9 in the left eye .
there was presence of crusted pus at the surgical wound site ( figure 1 ) .
a diagnosis of right eye preseptal abscess secondary to the infected surgical wound was made .
the patient was admitted and treated with intravenous co - amoxiclav 800 mg ( 25 mg / kg ) 8-hourly for a duration of 1 week .
chloramphenicol ointment was applied 8-hourly to the infected surgical wounds , together with instillation of topical chloramphenicol eye drops 6-hourly to the right eye . an emergency incision and drainage of the right upper eyelid was performed , and about 5 ml of pus was drained out .
post - incision and drainage , the right upper eyelid was still inflamed and swollen with partial mechanical ptosis ( figure 2 ) . in view of no improvement in the healing process ,
the antibiotic was changed to intravenous cefotaxime 750 mg ( 25 mg / kg ) 8-hourly for a duration of 1 week .
the topical antibiotic eye drop was also changed to topical moxifloxacin 6-hourly for the right eye .
however , there was still no improvement ; hence an antibiotic combination of intravenous ceftazidime 750 mg ( 25 mg / kg ) 8-hourly for 5 days and intravenous amikacin 210 mg ( 15 mg / kg ) 12-hourly for 3 days was commenced .
a third incision and drainage was performed together with removal of the gore - tex material . a culture from the final pus sample isolated multidrug - resistant acinetobacter species , which was resistant to all penicillins , cephalosporins , carbapenems , fluoroquinolones , and aminoglycosides
there was resolution of the right upper eyelid swelling , with no more pus discharge .
the patient was discharged , with chloramphenicol ointment to apply to the surgical wound 8-hourly for 2 weeks .
after 6 months follow - up ( about 3 months post - removal of gore - tex material ) , the patient s right upper eyelid was healed with scarring , but without ptosis ( figure 3 ) .
frontalis suspension surgery is a commonly used surgery in cases of congenital ptosis with poor levator function , chronic progressive ophthalmoplegia ( cpeo ) , muscular dystrophy , third nerve palsy , myasthenia gravis , and aponeurotic ptosis in elderly patients.1,3 there are several suspension materials that can be used in frontalis suspension surgery .
synthetic materials such as polypropylene suture , nylon suture , silicone , mersilene mesh , and gore - tex can also be used.5 gore - tex material or expanded polytetrafluoroethylene ( eptfe ) is suitable for suspension surgery because it is less bulky and less stretchable.5 it is a nontoxic polymer used in various other implantable medical products , including vascular grafts and hernia repair patches . unlike other implantable materials , eptfe is biocompatible .
micropores within the material are too small to allow infiltration of fibrovascular tissues hence allowing for easier removal or manipulation to adjust the eyelid height.6,7 however , its porous nature may allow proliferation of bacterial contaminants and cause abscess formation , resulting in a high risk of soft tissue complications . in our patient , constant
scratching may have led to infection of the wound . with tracking of the long , porous eptfe material through an open wound
the periorbital abscess was chronic and persistent even after treatment with multiple antibiotics and repeated incision and drainage , indicating the highly virulent nature of the causative organism .
this could be due to the formation of biofilm by the causative bacteria , especially on biomedical implants , causing antimicrobial resistance.8 complete resolution in our case occurred only after removal of the gore - tex material , which might have harbored the virulent microorganism .
there were a few other reports of complications of ptosis surgery such as granuloma and infection.2,3,9 in a retrospective study of 59 frontalis suspension procedures , infection with preseptal cellulitis appeared in one case ( 1.7% ) and required removal of the material , and in two cases ( 3.4% ) there were foreign body granulomas that were resolved by excision.10 there were other reports of post - ptosis surgery complicated by long - standing postoperative infection which were mostly associated with mycobacterium or candida infection.11,12 however , to our knowledge , there was no reported case of long - standing post - ptosis surgery infection involving multidrug - resistant acinetobacter species .
acinetobacter rarely colonizes implant materials;13 it commonly causes nosocomial infections such as pneumonia , urinary tract infection , and skin infections.14,15 in a delayed and long - standing post - frontalis surgery infection , multidrug - resistant organisms may be responsible for delayed healing and poor response to treatment .
surgical removal of infected slings and a prolonged course of antibiotics may be required for complete resolution .

Answer:
a 7-year - old boy had a case of congenital ptosis of the right eye and has undergone frontalis sling surgery using gore - tex material .
 there was no intraoperative or immediate postoperative complication .
 however , the patient defaulted his follow - up and presented with right eye preseptal abscess secondary to infected surgical wound 1 month after surgery .
 he was treated with multiple antibiotics and underwent repeated incision and drainage procedures .
 however , there was still no resolution of the right eye preseptal abscess .
 the patient s condition subsequently improved after removal of the gore - tex material and treatment with an antibiotic combination of ceftazidime and amikacin .
 microbiological analysis finally isolated the multidrug resistant acinetobacter species . at 6 months
 follow - up , his right upper eyelid was healed with scarring , but without ptosis .