Andrology: Factors influencing the outcome of in-vitro fertilization with epididymal spermatozoa in irreversible obstructive azoospermia

Microsurgical epididymal sperm aspiration (MESA) and in-vitrofertilization (IVF) were found to offer limited opportunityfor fatherhood to 45 men with obstructive azoospermia, due principallyto poor embryo implantation. Adequate sperm preparations wereobtained in 46/50 treatment cycles (92%), with the best motilityfound in the caput epididymis in 89% of cases. The mean fertilizationrate was 11.2% and fertilization occurred in 23 cycles (50%),with embryo transfer arising from 12/26 men with was aplasia(CAV), 4/9 with genital tract obstruction (EV) and 7/11 withirreversible vasectomy (VV). The overall implantation rate waslow, 8.7% per embryo transfer (11.7% per 2-3 embryo transfers)and was not improved by Fallopian transfer. There were two pregnancies(4% per cycle), both in the EV group where embryo formationand implatation (2/4, 50% per cycle) were optimum even thoughsperm preparations were paradoxically inferior to the CAV andVV groups. The spermatozoa retrieved in the two successful EVcycles were appreciably blood contaminated. Analysis of the21 failed embryo transfers showed delayed fertilization in 10cycles, cystic fibrosis (CF) mutation or familial disease in7/12 CAV men and the VV men were older (P<0.001). A pregnancywhich miscarried arose from a case of Young's syndrome, a carrierof CF mutation DF508. Male factors could thus be implicatedin the high embryo wastage of MESA cycles and might also beinfluencing implantation in other IVF procedures. Where feasible,male reconstructive surgery is preferable unless fertilizationcan be improved, possibly by speedier retrieval techniques orby permitting sperm capacitation in vitro, but probably moreeffectively by micro-assisted insemination.     

Construct validity of the PPVT with neuropsychological, intellectual, and achievement measures

The present investigation examined the construct validity of the Peabody Picture Vocabulary Test (PPVT) with learning-disabled children. The Wechsler Intelligence Scale for Children-Revised (WISC-R), the Wide Range Achievement Test, and the Halstead-Reitan Neuropsychological Battery were administered to 934 learning-disabled children. Seven factors were isolated on the basis of a principal-components factor analysis and Varimax rotation. PPVT scores were found to load on a factor similar to what has been labeled verbal comprehension on the WISC-R with little secondary loadings on any of the remaining six factors. Implications for practitioners and further research were discussed.     

Educational benefits of diversity in medical school: a survey of students.

PURPOSE: Many U.S. medical schools have abandoned affirmative action, limiting the recruitment and reducing the admission of underrepresented minority (URM) students even though research supports the premise that the public benefits from an increase in URM physicians and that URM physicians are likely to serve minority, poor, and Medicaid populations. Faculty and students commonly assume they benefit from peer cultural exchange, and the published evidence for the past two decades supports this notion. This research examined the students' perceptions of the educational merits of a diverse student body by surveying medical students at two schools. METHOD: In 2000, medical students from all four years at Harvard Medical School and the University of California, San Francisco, School of Medicine were enrolled in a telephone survey about the relevance of racial diversity (among students) in their medical education. Students responded to the interviewer's questions on a five-point Likert-type scale. RESULTS: Of the 55% of students who could be located, 97% responded to the survey. Students reported having little intercultural contact during their formative years but significantly more interactions during higher education years, especially in medical school. Students reported contacts with diverse peers greatly enhanced their educational experience. They strongly supported strengthening or maintaining current affirmative action policies in admissions. The responses and demography of the Harvard and UCSF students did not differ significantly, nor did they differ for majority students and URM students-all groups overwhelmingly thought that racial and ethnic diversity among their peers enhanced their education. CONCLUSIONS: Diversity in the student body enhanced the educational experiences of students in two U.S. medical schools.     

Mechanism of adenosine 3′,5′-monophosphate (cAMP)-induced increase in Ca2+ uptake by the sarcoplasmic reticulum in functionally skinned myocardial fibers

The increased rate of Ca²⁺ uptake and ATPase activity in isolated cardiac sarcoplasmic reticulum (SR) by adenosine 3,5-monophosphate (cAMP) has been shown to be activated by a cAMP-dependent protein kinase (cAMP kinase). Functionally skinned myocardial fiber preparations were used to study the mechanisms of cAMP action on the SR at the same time that tension was monitored. cAMP effects were studied on Ca²⁺-activated tension of the contractile proteins, and on Ca²⁺ uptake and release from the SR using caffeine-induced tension transients. Neither cyclic AMP (0.1–5 M) nor the catalytic subunit of cAMP kinase (0.1–1 M) (PK-C) significantly changed either the maximal or the submaximal Ca²⁺-activated tension. The areas of the tension transients were unchanged when cAMP was present in the releasing solution (release phase), and were significantly increased up to a mean of about 80% when cAMP or PK-C was present in the Ca²⁺ loading solutions (uptake phase). The increased tension transient was blocked by the heat-stable inhibitor of cAMP kinase. We conclude that cAMP-induced increases in Ca²⁺ uptake by the SR could play an important role in the positive inotropic effect. cAMP kinase could thus play a crucial role in the regulation of myocardial contractility.     

AMPK as a metabolic switch in rat muscle,liver and adipose tissue after exercise

An increasing body of evidence has revealed that activation of adenosine monophosphate (AMP)‐activated protein kinase (AMPK)‐activated protein kinase increases fatty acid oxidation by lowering the concentration of malonyl coenzyme A (CoA), an inhibitor of carnitine palmitoyl transferase 1. Studies carried out primarily in skeletal muscle suggest that AMPK modulates the concentration of malonyl CoA by concurrently phosphorylating and inhibiting acetyl CoA carboxylase (ACC), the rate limiting enzyme in malonyl CoA synthesis, and phosphorylating and activating malonyl CoA decarboxylase (MCD), an enzyme involved in its degradation. We have recently observed that AMPK and MCD activities are increased and ACC activity diminished in skeletal muscle, liver and, surprisingly, in adipose tissue 30 min following exercise (treadmill run) in normal rats. In liver and adipose tissue these changes were associated with a decrease in the activity of glycerol‐3‐phosphate acyltransferase (GPAT), which catalyses the first committed reaction in glycerolipid synthesis and, which like ACC, is phosphorylated and inhibited by AMPK. Similar changes in ACC, MCD and GPAT were observed following the administration of 5‐aminoimidazole 4‐carboxamide‐riboside (AICAR), further indicating that the exercise‐induced alterations in these enzymes were AMPK‐mediated. Conclusions: (1) AMPK plays a major role in regulating lipid metabolism in multiple tissues following exercise. (2) The net effect of its activation is to increase fatty acid oxidation and diminish glycerolipid synthesis. (3) The relevance of these findings to the regulation of muscle glycogen repletion in the post‐exercise state and to the demonstrated ability of AMPK activation to decrease adiposity and increase insulin sensitivity in rodents remains to be determined.     

Direct sequence evaluation of the major outer membrane protein gene variant regions of Chlamydia trachomatis subtypes D'', I'', and L2''.

The nucleotide sequences of variable segments (VS) 1, 2, and 4 for the major outer membrane protein gene (omp1) of Chlamydia trachomatis were determined for serologically defined subtypes D', I', and L2'. Asymmetric DNA amplification was used to produce single-stranded DNA for direct sequencing. Amino acid substitutions were detected in VS1, VS2, and VS4 for I', in VS2 for L2', and in VS4 for D'. DNA sequencing of omp1 variant regions may be an important method for evaluating the molecular epidemiology of Chlamydia spp.     

Characterization of monoclonal antibody CIBCNSH3 generated to the human EGF receptor

Monoclonal antibody CIBCNSH3 of IgG1 isotype has been generated against human epidermal growth factor receptor (EGFR) using MDA MB 468 breast carcinoma cell line as immunogen. Earlier studies have revealed that this MAb blocked growth factor-receptor interaction and thus inhibited cell proliferation and tumor growth. In the present paper, this MAb has been extensively characterized to evaluate its application in the study of human cancers. The results were compared with those obtained using a control MAb ICR 62 specific to EGFR. Competitive assay showed that this MAb bound to an epitope in the extracellular domain of the EGFR to which MAb ICR 62 also bound. This MAb immunoprecipitated the 170 kD glycoprotein. The specificity was further confirmed by the formation of a single discrete band in western blot analysis. By flow cytometric analysis this monoclonal antibody revealed high binding affinity with MDA MB 468 cells. By immunocytochemical assay, out of 35 breast tumors studied, 40% were found to exhibit strong cell membrane staining and in the case of 25 oral cancers studied, 56% were strong positive. High expression of EGFR was observed in MDA MB 468 cells and HN 5 cells. These studies clearly indicate that MAb CIBCNSH3 might prove useful to identify tumors with high level of expression of EGFR associated with poor prognosis.     

The effects of co-culture with human fibroblasts on human embryo development in vitro and implantation

In a human in-vitro fertilization (IVF) programme, the effect of co- culture of embryos with human fibroblasts was evaluated with respect to pregnancy rate and embryo development. Patients were included in the study after giving informed written consent. The IVF treatments were randomly assigned by stratification of both age (<36 versus > or =36 years) and previous IVF attempts (yes versus no). After fertilization was established, the zygotes were transferred to a 4-well dish with or without fibroblasts and cultured for 2 days. On the third day after ovum pick-up (OPU), cell number and quality [5 (good) to 1 (poor)] of the embryos were scored and a maximum of three embryos was transferred. Supernumerary embryos of good quality were cryopreserved. The design of this study was a group sequential trial with the objective of detecting differences between pregnancy rates following IVF with conventional incubation or incubation in co-culture with fibroblasts. This design included one evaluation at half-way data collection. In the study, 148 patients had an OPU, of whom 77 were allocated to the co-culture group. There was no statistically significant difference in pregnancy rate, cell number and embryo quality between the two groups. The ongoing pregnancy rate per embryo transfer was 27% in co-culture and 30% in the conventional culture group. The implantation rates per transferred embryo were 17 and 18% respectively. Using a multivariate logistic regression model for the probability of ongoing pregnancies, the odds ratio of co-culture, adjusted for age and previous IVF attempts, was not statistically significant. In conclusion, co-culture with human fibroblasts does not contribute to an improvement of embryo quality nor to a higher pregnancy rate after IVF in an unselected group of patients.