Extended work hours and risk of acute occupational injury: A case-crossover study of workers in manufacturing.

OBJECTIVE: This study was designed to determine whether injury risk among manufacturing workers was related to hours worked during the previous week. METHODS: A case-crossover design was utilized to contrast hours worked prior to an injury shift with those worked prior to a non-injury shift for hourly workers. Paired t-tests were used to determine significance of the difference. Conditional logistic regression was used to assess dose-response. RESULTS: Hours worked prior to injury significantly exceeded hours during the control week. Workers who worked more than 64 hr in the week before the shift had an 88% excess risk compared to those who worked 40 hr or fewer, P < 0.05. CONCLUSION: The study provides evidence that injury risk is related to time worked during the previous week. Control of overtime in manufacturing may reduce risk of worker injury.

Management of a Sabiá virus-infected patients in a US hospital.

OBJECTIVE: To describe the hospital precautions used to isolate a Sabiá virus (arenavirus: Arenaviridae)-infected patient in a US hospital and to protect hospital staff and visitors. DESIGN: Investigation of a single case of arenavirus laboratory-acquired infection and associated case-contacts. SETTING: A 900-bed, tertiary-care, university-affiliated medical center. PATIENTS OR OTHER PARTICIPANTS: The case-patient became ill with Sabiá virus infection. The case-contacts consisted of healthcare workers, coworkers, friends, and relatives of the case-patient. INTERVENTION: Enhanced isolation precautions for treatment of a viral hemorrhagic fever (VHF) patient were implemented in the clinical laboratory and patient-care setting to prevent nosocomial transmission. The enhanced precautions included preventing aerosol spread of the virus from the patient or his clinical specimens. All case-contacts were tested for Sabiá virus antibodies and monitored for signs and symptoms of early disease. RESULTS: No cases of secondary infection occurred among 142 case-contacts. CONCLUSIONS: With the frequency of worldwide travel, patients with VHF can be admitted to a local hospital at any time in the United States. The use of enhanced isolation precautions for VHF appeared to be effective in preventing secondary cases by limiting the number of contacts and promoting proper handling of laboratory specimens. Patients with VHF can be managed safely in a local hospital setting, provided that appropriate precautions are planned and implemented.

Effect of nitrous acid on lung function in asthmatics: a chamber study.

Nitrous acid, a component of photochemical smog and a common indoor air pollutant, may reach levels of 100 ppb where gas stoves and unvented portable kerosene heaters are used. Nitrous acid is a primary product of combustion and may also be a secondary product by reaction of nitrogen dioxide with water. Because the usual assays for nitrogen dioxide measure several oxides of nitrogen (including nitrous acid) together, previous studies of indoor nitrogen dioxide may have included exposure to and health effects of nitrous acid. To assess the respiratory effects of nitrous acid exposure alone, we carried out a double-blinded crossover chamber exposure study with 11 mildly asthmatic adult subjects. Each underwent 3-hr exposures to 650 ppb nitrous acid and to filtered room air with three 20-min periods of moderate cycle exercise. Symptoms, respiratory parameters during exercise, and spirometry after exercise were measured. A statistically significant decrease in forced vital capacity was seen on days when subjects were exposed to nitrous acid. This effect was most marked at 25 min and 85 min after exposure began. Aggregate respiratory and mucous membrane symptoms were also significantly higher with nitrous acid. We conclude that this concentration and duration of exposure to nitrous acid alters lung mechanics slightly, does not induce significant airflow obstruction, and produces mild irritant symptoms in asthmatics.

Pneumocystis carinii pneumonia and respiratory failure in AIDS. Improved outcomes and increased use of intensive care units.

To determine whether the outcome of intensive care for patients with AIDS, Pneumocystis carinii pneumonia (PCP), and respiratory failure has changed, we studied patients admitted to the intensive care units an San Francisco General Hospital from 1981 to 1988. We compared the course of patients with PCP and respiratory failure admitted to the intensive care unit from 1986 to 1988 with a similar cohort hospitalized from 1981 to 1985. The hospital survival rate for the 35 patients in the 1986 to 1988 cohort was 40%, compared with 14% for the 42 patients in the 1981 to 1985 cohort (p less than 0.01). Age, episode of PCP, time since AIDS diagnosis, anti-PCP therapy, and important clinical variables were similar in both cohorts. Corticosteroids were used commonly in the recent era. Patients who received steroids had an in-hospital survival rate of 46%, compared with 22% for those who did not receive steroids (p = NS). In a stepwise logistic regression model, ICU care in the recent era and higher serum albumin at the time of ICU admission were the only variables significantly associated with survival. The hospital survival of patients with PCP and respiratory failure has improved. The improvement could not be explained by patient selection or by better anti-PCP therapy. The apparent beneficial effect of corticosteroids deserves further study. The improvement in ICU outcome was reflected in increased ICU utilization by patients with AIDS, PCP, and respiratory failure.

Cytotoxicity of ketoconazole in malignant cell lines.

The cytotoxic effects of ketoconazole, an antifungal agent known to have some activity against human prostate cancer, adrenal cancer, and male metastatic breast cancer, were evaluated using colony-growth and clonogenic assays in eight malignant cell lines. The cytotoxicity of ketoconazole showed a dose- and time-dependent pattern, with the following concentrations inhibiting 90% of the growing colonies (IC90): MCF 7 (human breast cancer) 7.25 micrograms/ml, T 47 D (human breast cancer) 9.0 micrograms/ml, MiaPaCa (human pancreatic carcinoma) 10.0 micrograms/ml, COLO 357 (human pancreatic carcinoma), 9.5 micrograms/ml, HCT 8 (human colonic adenocarcinoma) 27.1 micrograms/ml, DU 145 (human prostatic cancer) 40.0 micrograms/ml, AR 42 J (rat pancreatic carcinoma) 9.0 micrograms/ml, and L1210 (murine leukemia) 8.6 micrograms/ml. Since a concentration of 10 micrograms/ml can be achieved in humans, the use of ketoconazole in human malignancies might be worthy of clinical evaluation.