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Commissioning ceremony kicks off graduation week

Posted: May 22, 2011 at 3:48 pm

military_commissioning_0185_web

Retired Air Force Major Robert H. Parent leads graduates in the oath of office aboard the USS Wisconsin.

Five medical school graduates bound for military service were in dress uniform Thursday on the fantail of the USS Wisconsin for the annual EVMS Military Commissioning Ceremony.

 

Family and friends were on hand in the shadow of the ship’s massive 16-inch guns to applaud the graduates and to help pin on symbols of their military rank.

 

Keynote speaker James J. Fletcher, DPM, MD, a 2003 EVMS graduate, recounted memories of his own commissioning ceremony aboard the ship and reminded them of the gravity of their commitment.

 

“It is already a noble thing to be a physician. You have also chosen another noble field. You have chosen to serve your country,” he said. “You have dedicated yourself to taking care of those who protect our country. They believe in you to take care of them, they trust in you to take care of their families while they’re gone. They trust in you that you will be there for them and that you will give best.”

 

See more images from the event and a full list of graduation-related activities.

Recommendation and review posted by Guinevere Smith

Thermostable recombinant xylanases from Nonomuraea flexuosa and Thermoascus aurantiacus show distinct properties in the hydrolysis of xylans and pretreated wheat straw

Posted: May 22, 2011 at 3:48 pm

Background:
In the hydrolysis of lignocellulosic materials, thermostable enzymes decrease the amount of enzyme needed due to higher specific activity and elongate the hydrolysis time due to improved stability. For cost-efficient use of enzymes in large-scale industrial applications, high-level expression of enzymes in recombinant hosts is usually a prerequisite. The main aim of the present study was to compare the biochemical and hydrolytic properties of two thermostable recombinant glycosyl hydrolase families 10 and 11 (GH10 and GH11, respectively) xylanases with respect to their potential application in the hydrolysis of lignocellulosic substrates.
Results:
The xylanases from Nonomuraea flexuosa (Nf Xyn11A) and from Thermoascus aurantiacus (Ta Xyn10A) were purified by heat treatment and gel permeation chromatography. Ta Xyn10A exhibited higher hydrolytic efficiency than Nf Xyn11A toward birchwood glucuronoxylan, insoluble oat spelt arabinoxylan and hydrothermally pretreated wheat straw, and it produced more reducing sugars. Oligosaccharides from xylobiose to xylopentaose as well as higher degree of polymerization (DP) xylooligosaccharides (XOSs), but not xylose, were released during the initial hydrolysis of xylans by Nf Xyn11A, indicating its potential for the production of XOS. The mode of action of Nf Xyn11A and Ta Xyn10A on glucuronoxylan and arabinoxylan showed typical production patterns of endoxylanases belonging to GH11 and GH10, respectively.
Conclusions:
Because of its high catalytic activity and good thermostability, T. aurantiacus xylanase shows great potential for applications aimed at total hydrolysis of lignocellulosic materials for platform sugars, whereas N. flexuosa xylanase shows more significant potential for the production of XOSs.

Recommendation and review posted by Guinevere Smith

Antisperm antibodies are not associated with pregnancy rates after IVF and ICSI: systematic review and meta-analysis

Posted: May 22, 2011 at 3:47 pm

BACKGROUND

Several studies have examined the relationship between direct antisperm antibody (ASA) levels in semen and pregnancy rate after advanced assisted reproductive technologies (ARTs) but the results have been inconsistent. The aim of our study was to further evaluate the relationship between ASA and pregnancy after IVF or ICSI by systematic review and meta-analysis.

METHODS

We conducted a systematic Medline search of all relevant full papers on direct semen ASA and pregnancy after IVF or ICSI. Three investigators independently reviewed the papers, followed by group discussion to choose the included papers. Meta-analysis was performed to get an odds ratio (OR) for the effect of ASA on pregnancy using IVF or ICSI.

RESULTS

The study identified and analyzed 16 valid studies (10 IVF and 6 ICSI). The study characteristics (including the ASA cutoff values) were heterogeneous. Our meta-analysis revealed that the combined OR for failure to achieve a pregnancy using IVF or ICSI in the presence of positive semen ASA was 1.22 (95% CI: 0.84, 1.77) and 1.00 (95% CI: 0.72, 1.38), respectively. The overall (IVF + ICSI) combined OR was 1.08 (95% CI: 0.85, 1.38).

CONCLUSION

This systematic review and meta-analysis indicate that semen antisperm antibodies are not related to pregnancy rates after IVF or ICSI, suggesting that both forms of ART remain viable options for infertile couples with semen ASA. However, additional, well-designed prospective studies using appropriate ASA cutoff levels are needed to further address this issue.

Recommendation and review posted by Guinevere Smith

Identification and characterization of repopulating spermatogonial stem cells from the adult human testis

Posted: May 22, 2011 at 3:47 pm

BACKGROUND

This study was conducted to identify and characterize repopulating spermatogonial stem cells (SSCs) in the adult human testes.

METHODS

Testes biopsies from obstructive azoospermic patients and normal segments of human testicular tissue were used. Flow cytometry, real-time PCR and immunohistochemical analysis were performed. Purified human spermatogonia were transplanted into busulfan-treated recipient mouse testes and integrated cells were detected by human nuclear protein antibody co-localized with stem cell and germ cell markers.

RESULTS

Testicular biopsies collected from obstructive azoospermic men showed similar morphology and distribution of markers to the normal human testes. Flow cytometry showed distinct populations of stage-specific embryonic antigen-4 (SSEA-4), CD49f and CD90 positive cells in the adult human testes. SSEA-4 (+) cells showed high expression levels of SSC-specific genes and high levels of telomerase activity. Extensive colonization of human cells in the mouse testes indicates the presence of highly enriched populations of SSCs in the SSEA-4 (+) sorted cells. All the HNP (+) cells in the mouse testes were positive for germ cell marker dead box mRNA helicase and only half of them were dimly positive for c-kit. In addition, subpopulations of human spermatogonia that colonized mouse testes were positively stained for CD49f, GPR-125, Nanog and Oct-4 indicating the existence of population of cells among human spermatogonia with SSC and pluripotent characteristics.

CONCLUSIONS

This study clearly demonstrates that repopulating human SSCs have phenotypic characteristics of SSEA-4+, CD49f+, GPR-125+and c-Kit neg/low. The results have direct implications for enrichment of human spermatogonia for further culture and germ cell differentiation studies.

Recommendation and review posted by Guinevere Smith

Vitamin D is positively associated with sperm motility and increases intracellular calcium in human spermatozoa

Posted: May 22, 2011 at 3:47 pm

BACKGROUND

The vitamin D receptor (VDR) is expressed in human spermatozoa, and VDR-knockout mice and vitamin D (VD) deficiency in rodents results in impaired fertility, low sperm counts and a low number of motile spermatozoa. We investigated the role of activated VD (1,25(OH)2D3) in human spermatozoa and whether VD serum levels are associated with semen quality.

METHODS

Cross-sectional association study of semen quality and VD serum level in 300 men from the general population, and in vitro studies on spermatozoa from 40 men to investigate the effects of VD on intracellular calcium, sperm motility and acrosome reaction. All men delivered samples for routine semen analysis and blood for measurements of follicle stimulating hormone, Inhibin B, 25-hydroxy-VD, albumin, alkaline phosphatase, calcium and parathyroid hormone (PTH).

RESULTS

In the association study, 44% were VD insufficient (<50 nM), and VD was inversely correlated with PTH (P < 0.0005). VD serum levels correlated positively with sperm motility and progressive motility (P < 0.05), and men with VD deficiency (<25 nM) had a lower proportion of motile (P = 0.027), progressive motile (P = 0.035) and morphologically normal spermatozoa (P = 0.044) compared with men with high VD levels (>75 nM). 1,25(OH)2D3 increased intracellular calcium concentration in human spermatozoa through VDR-mediated calcium release from an intracellular calcium storage, increased sperm motility and induced the acrosome reaction in vitro.

CONCLUSIONS

1,25(OH)2D3 increased intracellular calcium concentration, sperm motility and induced the acrosome reaction in mature spermatozoa, and VD serum levels were positively associated with sperm motility, suggesting a role for VD in human sperm function.

Recommendation and review posted by Guinevere Smith

The use of novel biochemical markers in predicting spontaneously resolving ‘pregnancies of unknown location’

Posted: May 22, 2011 at 3:47 pm

BACKGROUND

‘Pregnancies of unknown location’ (PULs) include viable and failing intrauterine and extrauterine pregnancies. The aim of this study was to evaluate the role of novel biochemical markers in the prediction of spontaneous resolution of PULs.

METHODS

Serum samples were taken at the first visit to the pregnancy unit for measuring the traditional markers β-hCG and progesterone, and for inhibin A, inhibin pro-αC-related immunoreactivity (inhibin pro-αC-RI) and insulin-like growth factor-binding protein 1 (IGFBP-1). Follow-up was continued until the pregnancy had resolved, the location of the pregnancy and viability was determined or treatment was required. Outcomes were dichotomized into ‘spontaneous resolution’ and ‘other outcome’ categories.

RESULTS

One-hundred and nine cases of PUL were included in the data analysis. Spontaneous resolution occurred in 70% and a further scan was required in 30% to reach a diagnosis. Levels of progesterone and inhibin A were significantly lower (both P < 0.001) and levels of IGFBP-1 significantly higher (P = 0.02) in the pregnancies that spontaneously resolved than in those pregnancies that required further intervention. In decision tree analysis, the novel markers were less useful than progesterone and β-hCG in predicting spontaneously resolving PULs. Inhibin pro-αC-RI and IGFBP-1 were not useful in the prediction of spontaneously resolving PULs. Inhibin A is more predictive than β-hCG alone, but serum progesterone is the best single marker and progesterone and hCG together continues to be the best way of predicting spontaneously resolving PULs.

CONCLUSIONS

These novel biochemical markers are not clinically useful in predicting spontaneously resolving PULs.

Recommendation and review posted by Guinevere Smith


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