Legionella in cooling towers.

Legionellosis (Legionnaires' disease and Pontiac fever) outbreaks have been associated with aerosols ejected from contaminated cooling towers--wet-type heat rejection units (WTHRUs) used to dissipate unwanted heat into the atmosphere. The Vermont Department of Health undertook a program to inventory, inspect, and sample all WTHRUs in Vermont from April 1981 to April 1982. All WTHRUs were sampled for Legionella pneumophila and data were obtained for location, design, construction, and operating characteristics. Of the 184 WTHRUs operating, statistical analyses were performed on those 130 which were sampled for L. pneumophila only once during the study period. Of these, 11 (8.5%) were positive for L. pneumophila. Sources of makeup water and period of operation had significant association with the recovery of L. pneumophila. Five out of 92 towers (5.4%) utilizing surface water sources for cooling were positive for L. pneumophila, in contrast to 6 positive towers of the 38 units (15.8%) which obtained makeup water from ground water sources (p = .054 by chi-square test). Nearly 15% of the 54 units which operated throughout the year were positive, compared to less than 4% of the 76 towers operating seasonally (p = .03 by chi-square test). The mean pH of the cooling water in units where L. pneumophila was recovered (8.3) was significantly higher than the mean pH of 7.9 in units testing negative (p less than .05 by t-test). In addition, the mean log-transformed turbidity of positive towers, 0.03 nephelometric units (ntu), was significantly lower than the mean of log turbidity of negative towers, 0.69 ntu (p less than .02 by t-test).     

Radical prostatectomy: anatomical predictors of success or failure

A total of 143 patients underwent radical prostatectomy. Surgical specimens were evaluated with respect to local extent of disease, Gleason grade of the primary and relative nuclear roundness of the surgical specimen. The probability of disease control in the total population was 88 per cent at 5 years. Only 8 per cent of the patients who had disease confined to the specimen failed compared to 14 per cent of those who demonstrated extension outside of the surgical margins. The incidence of failure increased as a function of seminal vesicle involvement. Seminal vesicle involvement was greatest among patients with a Gleason grade greater than 7. Postoperative radiation did not offer any apparent advantage in patients with positive margins.     

Herpetic croup: two case reports and a review of the literature

Croup is an acute infectious illness usually occurring in children; it is characterized by brassy cough and stridor. The main pathogens include mainly parainfluenza and influenza viruses. Recently there have been reports of prolonged croup caused by the herpes simplex viruses. We report two cases of prolonged croup due to herpes simplex types 1 and 2. We also review and summarize the reported pediatric cases of herpetic croup.     

Anesthetic action of opiates: correlations of lipid solubility and spectral edge

The ability of opiates to be a complete anesthetic has been assessed in animals. These studies have investigated the serum levels of opiate required to produce a decrease in anesthetic requirement for a concomitantly administered inhalation anesthetic. A linear dose-response relation has been observed between opiate serum level and reduction in anesthetic requirement up to the level of 50% reduction in minimum alveolar anesthetic concentration (MAC). These studies have not demonstrated the production of one MAC anesthesia by the opiates. Recent EEG studies have provided another means of comparing the central nervous system effects of opiates and inhalation anesthetics. The serum levels of several opiates associated with a 50% reduction (IC50 or 50% inhibitory concentration) in maximal spectral edge frequency (SEF) have been reported. The free, unionized serum levels of each opiate at IC50 in humans or 50% MAC reduction in animals are remarkably similar. We calculated brain lipid opiate content at these serum levels using available physiochemical data. The calculated nanogram and molar brain lipid contents of the drugs fell within a 10-fold range while serum levels varied by 5000-fold. This similarity in membrane lipid content in association with EEG and anesthetic effects suggests that opiate "anesthesia" may involve a membrane effect in addition to the well established receptor interaction.     

Feasibility analysis for medical services.

Feasibility analysis is an important aspect of business planning. A feasibility study is a study of the impacts of revenues, cost, and returns on a decision. It helps answer the questions of "What share of total sales can be attained?" "What revenues will be generated?" "What costs will be incurred?" "What will be the return on investment?" The discipline of going through a systematic approach to analyze market demand, cost requirements, and return on investment will improve business decisions by eliminating risk and increasing the possibility of successful ventures.     

Attitudes toward prevention of cardiovascular diseases among first-year students at eight American medical schools, 1983-1985

First-year medical students at eight U.S. medical schools were surveyed by written questionnaire in 1983-1985 to determine their attitudes toward cardiovascular diseases prevention at medical school entry. An overall response rate of 92% was achieved (2,654 questionnaires), and 97% of responders provided complete and analyzable survey data. Response rates at five of eight medical schools were 98-100%, and one school each had rates of 67, 84, or 90%. Differences in mean attitude responses from school to school were small, as were differences between men and women or between blacks and whites. This survey found that entering medical students have generally positive attitudes toward the effectiveness of preventive cardiology practice as well as toward the importance of research efforts in cardiovascular disease prevention. Students frequently indicated, however, that it is "extremely difficult" to change patients' unhealthful habits and that "physician encouragement" may not be sufficient to help patients achieve more healthful behaviors. These findings could be helpful in directing educational efforts for medical students. The data suggest that major emphasis should be placed on conveying facts regarding the physicians' efficacy in clinical preventive cardiology and on teaching the skills of preventive cardiology practice. Less emphasis appears to be necessary on encouraging positive attitudes about the importance of prevention since current students' attitudes appear to be already positive in this dimension.     

An update on digoxin

This review deals briefly with recent developments in the therapeutic drug monitoring of digoxin. Strategies for decreasing the interference by digoxin metabolites, digoxin-like factors, and spironolactone metabolites in immunoassays of digoxin are discussed. Other issues addressed include the development of alternative methods of analysis, such as receptor assays and "high-pressure" liquid chromatography; digoxin-like factors in hypertension; drug-drug interactions; redistribution of digoxin stores in the body; and forensic considerations.