The Evolving Stethoscope: Insights Derived from Studying Phonocardiography in Trainees.

Phonocardiography (PCG) is used as an adjunct to teach cardiac auscultation and is now a function of PCG-capable stethoscopes (PCS). To evaluate the efficacy of PCG and PCS, the authors investigated the impact of providing PCG data and PCSs on how frequently murmurs, rubs, and gallops (MRGs) were correctly identified by third-year medical students. Following their internal medicine rotation, third-year medical students from the Georgetown University School of Medicine completed a standardized auscultation assessment.

Effect of subdermal oestrogen and oestrogen/testosterone implants on calcium and phosphorus homeostasis after oophorectomy.

Various biochemical aspects of calcium metabolism were studied serially in 32 post-menopausal patients treated with subdermal implants of oestrogen, either alone or in combination with testosterone. Significant reductions in serum calcium, serum phosphate, the renal phosphate threshold (TmPO4) and the urinary calcium/creatinine ratio were observed for periods of up to 6 mth in both treatment groups as compared with baseline. The findings suggest that oestrogen replacement therapy by subdermal implant is effective in reversing the characteristic alterations in calcium metabolism which occur in the post-menopausal patient.

Different control circuits for growth rate-dependent regulation of 6-phosphogluconate dehydrogenase and protein components of the translational machinery in Escherichia coli.

Previous studies showed that the level of 6-phosphogluconate (6PG) dehydrogenase increases about fourfold with increasing growth rate when the growth rate is varied by varying the carbon source. When the growth rate was reduced by anaerobic growth or by using mutations to divert metabolism to less efficient pathways, the level of 6PG dehydrogenase was the same as in a wild-type strain growing aerobically on other carbon sources that yielded the same growth rate. Thus, expression of gnd, which encodes 6PG dehydrogenase, is regulated by the cellular growth rate and not by specific nutrients in the medium.