Gloria E. Sarto

Hormone replacement therapy in the menopause: A pro opinion

The preponderance of data support the benefits of HRT in estrogen-deprived and menopausal women to reduce the risks of osteoporosis and cardiovascular disease and to enhance quality of life and life expectancy. Controversies exist with regards to the risk-benefit ratio in women with a history of estrogen-dependent gynecologic tumors or breast cancer. Until these issues are resolved, physicians must carefully weigh, on an individual basis for each patient, the potential risks against the known benefits. Women should be counseled regarding the benefits of exercise, weight control, breast feeding, and cessation of cigarette smoking or excessive alcohol to reduce their risks of cancer, cardiac disease, and/or osteoporosis. HRT is not a panacea for an unhealthy lifestyle. When ERT is contraindicated, viable alternatives to retard bone loss and/or control vasomotor symptoms include calcium supplementation and progestin therapy. The role of tamoxifen as an alternative HRT in women at increased risk for breast cancer development is currently under investigation.

Gene-rich chromosome regions and autosomal trisomy

SummaryCases of autosomal trisomy and trisomy mosaicism among liveborn infants are reviewed, and a second case of chromosome 3 trisomy mosaicism is described. The occurrence of autosomal trisomy for a particular chromosome is in general negatively correlated with the number of genes which have been localized to that chromosome. It is also positively related to the Q-brightness of the chromosome, which reflects its content of intercalary heterochromatin. Furthermore there are significantly fewer autosomal trisomics for chromosomes which contain hot spots for mitotic chiasmata in Bloom syndrome (chromosomes 1, 3, 6, 11, 12, 17, 19, and 22), compared with similar-sized control chromosomes 2, 4, 7, 9, 10, 18, 20, and 21. This is interpreted as further evidence for the gene richness of the hot spots which, being active, are extended in interphase and are therefore available for mitotic crossing over. The gene richness of these short Q-dark regions is also borne out by the scarcity of trisomic abortions for the chromosomes involved (the embryo dies before the abortion is recognized) and by the higher number of genes localized to these chromosomes compared with the control chromosomes.

Assessing clinical competence of medical students in women's health care : Use of the objective structured clinical examination

Objective To assess clinical competency of third-year medical students completing a problem-oriented, primary care emphasis clerkship in obstetrics and gynecology using an objective structured clinical examination, and to determine the feasibility of implementing the objective structured clinical examination in the curriculum. Methods Sixteen groups of third-year medical students were evaluated prospectively on their exit performances with a six-station objective structured clinical examination designed to test clinical competency in basic primary care obstetrics-gynecology. Consistency of scores across stations, differences in performance for separate groups, and relationship of objective structured clinical examination scores compared with other indicators of medical proficiency, such as written examinations and faculty evaluations, were assessed. Results One hundred ninety-eight students were evaluated over 25 months. Test reliability across stations revealed a values ranging between .50 and .56. Correlations between performance on the objective structured clinical examination and the written test (r = .10) were low, demonstrating that the objective structured clinical examination clearly tests a separate domain of student capability. Cost of the objective structured clinical examination was

What causes the abnormal phenotype in a 49,XXXXY male?

81.66 per student. Conclusion The objective structured clinical examination is a reliable and valid test of the clinical competence of medical students in the primary health care of women. It provides information that is not obtained by more traditional assessment modalities at a reasonable cost.

Segregation after mitotic crossing-over in isodicentric X chromosomes

SummaryThe chromosome replication pattern of a man with 49,XXXXY was analyzed using 3H-thymidine and autoradiography as well as BrdU and acridine orange. The former technique showed a highly irregular replication pattern; the latter revealed one early replicating X chromosome, and the other three more or less asynchronously replicating. Two hypotheses seem to explain best the abnormal phenotype of males with an XXXXY sex chromosome constitution: (1) The number of the always active regions (tip of Xp) and of the possibly always active regions (the Q-dark regions on both sides of the centromere) is increased from one to four. (2) The replication pattern of the late-replicating X chromosomes is highly asynchronous, which might affect the phenotype. The possibility that more than one X chromosome might remain active in some cells, an even more abnormal and obviously deleterious situation, is still open.

In situ hybridization solution and process

Segregation after mitotic crossing-over in an isodicentric (idic) X chromosome with one active and one inactive centromere has given rise to two new cell lines, one in which the idic(Xpter) chromosome has two active centromeres (most of these chromosomes also have an inversion) and another in which neither centromere is active. The two X chromosomes are attached at the telomeres of their short arms. Similar segregation has given rise to two other cell lines with idic(Xq-) chromosomes. Other observations on segregation after mitotic crossing-over are reviewed. Unequal crossing-over has apparently played a major role in the evolution of various genes and heterochromatin. Retinoblastoma and Wilms tumor are in some cases associated with homozygosity of a chromosome segment resulting from mitotic crossing-over. Similarly, the high incidence of cancer in Bloom syndrome may be caused by mitotic crossing-over leading to homozygosity or amplification of oncogenes.