Comparative rates of androgen production and metabolism in Caucasian and Chinese subjects

Clinically apparent prostate cancer occurs more commonly among Caucasians living in Western countries than in Chinese in the Far East. Prior studies demonstrated diminished facial and body hair and lower levels of plasma 3 alpha-androstanediol glucuronide and androsterone glucuronide in Chinese than in Caucasian men. Based upon these findings, investigators postulated that Chinese men could have diminished 5 alpha-reductase activity with a resultant decrease in prostate tissue dihydrotestosterone levels and clinically apparent prostate cancer. An alternative hypothesis suggests that decreased 3 alpha-androstanediol glucuronide and androsterone glucuronide levels might reflect reduced production of androgenic ketosteroid precursors as a result of genetic or environmental factors. The present study examined 5 alpha-reductase activity, androgenic ketosteroid precursors, and the influence of genetic and environmental/dietary factors in groups of Chinese and Caucasian men. We found no significant differences in the ratios of 5 beta-:5 alpha-reduced urinary steroids (a marker of 5 alpha-reductase activity) between Chinese subjects living in Beijing, China, and Caucasians living in Pennsylvania. To enhance the sensitivity of detection, we used an isotopic kinetic method to directly measure 5 alpha-reductase activity and found no difference in testosterone to dihydrotestosterone conversion ratios between groups. Then, addressing the alternative hypothesis, we found that the Caucasian subjects excreted significantly higher levels of individual and total androgenic ketosteroids than did their Chinese counterparts. To distinguish genetic from environmental/dietary factors as a cause of these differences, we compared Chinese men living in Pennsylvania and a similar group living in Beijing, China. We detected a reduction in testosterone production rates and total plasma testosterone and sex hormone-binding levels, but not in testosterone MCRs in Beijing Chinese as a opposed to those living in Pennsylvania. Comparing Pennsylvania Chinese with their Caucasian counterparts, we detected no significant differences in total testosterone, free and weakly bound testosterone, sex hormone-binding globulin levels, and testosterone production rates. Taken together, these studies suggest that environmental/dietary, but not genetic, factors influence androgen production and explain the differences between Caucasian and Chinese men.     

Unbiased and efficient estimation of bladder volume with MR imaging

Almost all methods of measuring residual volume of urine in the bladder of patients undergoing urologic assessment are biased to an unknown extent. The authors describe the application of an unbiased stereologic technique for estimating the volume of bladder urine known as the Cavalieri method. The method requires imaging of a series of systematic (ie, equally spaced) parallel sections through the bladder. Such data can be conveniently obtained with magnetic resonance (MR) imaging. If sampling begins at a position randomly chosen within the distance corresponding to the section interval, bladder volume is estimated without bias as the sum of the areas of the bladder sections on the images multiplied by the section interval. Computer-aided point-counting techniques represent an efficient means of obtaining the required section area estimates. Optimum sectioning and point counting densities for estimating bladder volume were established by analyzing detailed data sets obtained in five volunteers. It was shown that if an average of only 20 points were counted in each of only five systematic sections through the bladder, the volume of bladder urine was estimated with a coefficient of error of about 5%. By studying these five volunteers and an additional 13 with MR imaging and the Cavalieri method, the authors showed that the difference between the volume of urine in the bladder before and after micturition is unbiased (ie, shows no systematic difference) with respect to the volume of urine voided by the subjects.     

Role of pelvic nerves in the postcopulatory abbreviation of behavioral estrus in female rats

The role of the pelvic nerves in the postmating abbreviation of behavioral estrus in domestic female rats was investigated. Mating during a period of 40 min at the beginning of hormonally induced estrus in spayed female rats resulted in a rapid decrease in receptivity as measured hourly by the lordosis response. Moreover, the length of the receptive period was significantly shortened by mating at the start of the period. Bilateral pelvic nerve transection completely abolished these effects of mating. Continuous exposure to sexually active males throughout the period of receptivity resulted in a more pronounced decline in receptivity but again was without effect in pelvectomized females. Apparently genital stimuli mediated by the pelvic nerves are responsible for the postcopulatory decrease in receptive behavior in the female rat.     

Phase relation, crystal structure, and magnetic properties of La-Co-Si alloys

OBJECTIVES: To identify ICU-specific predictors of mortality. DESIGN: An inception cohort study. SETTING: Barnes Hospital, an academic tertiary care center. PATIENTS: Consecutive patients, requiring mechanical ventilation, admitted to the medical intensive care unit (ICU) (75 patients), surgical ICU (100 patients), and cardiothoracic ICU (102 patients). INTERVENTIONS: Prospective data collection and outcomes evaluation. MEASUREMENTS AND MAIN RESULTS: Stepwise logistic regression analysis identified the following variables to be independent predictors of mortality for the individual ICUs: medical ICU, an Organ System Failure Index (OSFi) greater than or equal to 3; surgical ICU, OSFI greater than or equal to 3; cardiothoracic ICU, OSFI greater than or equal to 3, requiring acute dialysis, and the occurrence of an iatrogenic event. The same analysis was repeated after removing the OSFI as a potential confounding variable. Independent predictors of mortality identified in this subsequent analysis were as follows: medical ICU, occurrence of renal failure; surgical ICU, supine head positioning, acute physiology score greater than or equal to 10, preadmission lifestyle score greater than or equal to 2; cardiothoracic ICU, requiring acute dialysis, occurrence of ventilator-associated pneumonia, and the occurrence of an iatrogenic event. CONCLUSIONS: We identified the presence of ICU-specific predictors of mortality amongst the three ICUs examined. These data suggest that ICU-specific interventions could be developed to improve the quality of patient care and potentially to reduce patient mortality.     

The use of meditation--relaxation techniques for the management of stress in a working population

The efficacy of meditation-relaxation techniques has been widely researched in the laboratory, but their effectiveness for management of stress in organizational settings is still relatively unexplored. The present study compared relaxation and control conditions as part of a program of stress-reduction in industry. A total of 154 New York Telephone employees self-selected for stress learned one of three techniques--clinically standardized meditation (CSM), respiratory one method meditation (ROM) or progressive relaxation (PMR)--or served as waiting list controls. At 5.5 months, the treatment groups showed clinical improvement in self-reported symptoms of stress, but only the meditation groups (not the PMR group) showed significantly more symptom reduction than the controls. The meditation groups had a 78% compliance rate at 5.5 months with treatment effect seen whether subjects practiced their techniques frequently or occasionally. The safe and inexpensive semi-automated meditation training has considerable value for stress-management programs in organizational settings.     

Basic laparoscopic knowledge among gynecologic laparoscopists

OBJECTIVE: Our purpose was to assess the basic knowledge of laparoscopy and laparoscopic sterilization among gynecologic laparoscopists. STUDY DESIGN: A four-part multiple-choice test designed for use in residency training, covering basic aspects of laparoscopy and laparoscopic sterilization, was distributed to 155 registrants at a gynecologic surgery postgraduate course. Test results were compared among subgroups, as well as with results for 23 residents who had taken the test before their rotation in laparoscopic sterilization. RESULTS: Residents scored higher than practitioners on all test segments. No practitioner achieved the 85% correct passing score required of residents. Practitioner scores did not increase as the number of laparoscopic sterilizations performed per year increased, but higher test scores were associated with more recent completion of residency. CONCLUSION: Basic knowledge of laparoscopic sterilization among practicing gynecologists, as measured by a test designed for residents, is less than that of the residents.     

Sensitive quantitation of endotoxin by enzyme-linked immunosorbent assay with monoclonal antibody against Limulus peptide C

Limulus peptide C, a 28-amino-acid fragment of coagulogen formed by the reaction of endotoxin with Limulus amebocyte lysate, was synthesized, and a monoclonal antibody against it was raised. A new microassay for endotoxin was developed, using this antibody in an enzyme-linked immunosorbent assay for generated peptide C-like immunoreactivity. A linear relationship between absorbance and endotoxin concentration was obtained. Control standard endotoxin in water could be detected to a level of 0.001 endotoxin unit per ml. The endotoxin levels in plasma samples from normal humans, rabbit, mice, and guinea pigs were generally found to be below the detection limit of 0.01 endotoxin unit per ml of plasma. The color and turbidity of specimens did not interfere with the assay. The consumption of Limulus amebocyte lysate in the assay was less than 5% of that in the gel-clot and chromogenic assays. With raw lysate, which was much more stable in solution than chloroform-treated lysate, the assay was still highly sensitive to endotoxin but was totally unresponsive to natural glucans. The monoclonal antibody cross-reacted with peptide C-like immunoreactivity generated in Tachypleus amebocyte lysate, which gave equal sensitivity in the endotoxin assay.