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71.
72.
Hirsh A.V.; Mills C.; Bekir J.; Dean N.; Yovich J.L.; Tan S.L. 《Human reproduction (Oxford, England)》1994,9(9):1710-1716
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. 相似文献
73.
Construct validity of the PPVT with neuropsychological, intellectual, and achievement measures 总被引:2,自引:0,他引:2
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. 相似文献
74.
Dean K Whitla Gary Orfield William Silen Carole Teperow Carolyn Howard Joan Reede 《Academic medicine》2003,78(5):460-466
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. 相似文献
75.
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. 相似文献
76.
N. B. Ruderman H. Park V. K. Kaushik D. Dean S. Constant M. Prentki A. K. Saha 《Acta physiologica (Oxford, England)》2003,178(4):435-442
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. 相似文献
77.
Direct sequence evaluation of the major outer membrane protein gene variant regions of Chlamydia trachomatis subtypes D'', I'', and L2''. 总被引:3,自引:0,他引:3
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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. 相似文献
78.
Udayachander M Meenakshi A Sivakumar N Kumar RR Shankar SG Dean CJ Modjtahedi H 《Human antibodies》1999,9(3):149-154
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. 相似文献
79.
Dean E. Schraufnagel 《Anatomical record (Hoboken, N.J. : 2007)》1992,233(4):547-554
In a recent study, rats given monocrotaline underwent angiogenesis on their pleural surfaces. The rats also had novel structures in their bronchovascular bundles that were detected by scanning electron microscopy of vascular casts. These vessels could have been either new blood capillaries or dilated lymphatic capillaries. To determine if these structures were lymphatics or new blood vessels, specimens from animals that were undergoing angiogenesis were compared to those that were not. Finding similar structures in normal animals would imply that they were lymphatic. The second purpose of this work was to describe the three-dimensional anatomy of the lymphatics of the lung. Cast lymphatics were found in most lungs with edema or angiogenesis, but were rare in other conditions. The vascular structures in question were found in animals not undergoing angiogenesis and were, therefore, lymphatic. Additionally, scanning electron angiogenesis and were, therefore, lymphatic. Additionally, scanning electron microscopy of casts showed several distinct forms of lymphatics in the lung. Prelymphatics are tissues planes beneath the pleura and around bronchovascular structures. They join reservoir, conduit or tubulo-saccular lymphatics. Reservoir lymphatics are broad ribbon-like structures with textured surfaces and small laterally branching pouches. They occur on the pleural surface, are closely linked with prelymphatics, and join conduit lymphatics. Conduit lymphatics are tubular structures that may contain valves, twist and go great distances without accepting tributaries. On the pleural surface, they may wind around blood vessels and vary greatly in diamater. Sacculo-tubular lymphatics surround arteries, veins and bronchioles. They have thin walls with wide saccular segments. They may be so dense that they form cylinders around the vessels or airways. Different forms of lung lymphatics suggest different function and potential. © 1992 Wiley-Liss, Inc. 相似文献
80.
16S Ribosomal DNA Typing for Identification of Pathogens in Patients with Bacterial Keratitis 总被引:2,自引:1,他引:2
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C. Michele Knox Vickey Cevellos Deborah Dean 《Journal of clinical microbiology》1998,36(12):3492-3496
The identification of pathogens in patients with bacterial keratitis remains problematic because standard diagnostic tests are negative for 40 to 60% of patients. A cross-sectional study was undertaken to determine if PCR and sequence analysis of 16S ribosomal DNA (rDNA) could be used to detect bacterial pathogens in patients with keratitis. Corneal specimens were collected for culture and rDNA typing. Variable segments of each rDNA specimen were amplified by PCR, sequenced, and aligned with the sequences in GenBank. Eleven patients had microbiologically documented bacterial keratitis, while 17 patients had keratitis due to other causes. Nine (82%) of 11 bacterial keratitis patients were PCR positive; each sequencing result matched the culture results. Seventeen (100%) patients with nonbacterial keratitis were PCR negative. Our data suggest that 16S rDNA typing holds promise as a rapid alternative to culture for identifying pathogens in patients with bacterial keratitis. 相似文献