Search PubMed⌕ Search

Biomedical subjects

L Bernstein

Publications and source records attributed to L Bernstein.

At least 253 records · Page 14Linked to original sources
PubMed1982

Pulmonary function in firefighters: a six-year follow-up in the Boston Fire Department.

Tests of ventilatory capacity, objective cough, and standardized respiratory questionnaires were used in a prospective study to measure the effect of firefighting on pulmonary function in a cohort of 951 white Boston firefighters between 1970-1976. During the six years of follow-up, the mean annual decrements in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were 36 and 29 ml per year, respectively. At the end of the study in 1976, the mean FEV1 for this group was 98.3% of the level predicted for healthy nonsmoking adults, while the FVC was 97.8%. Current cigarette smoking was associated with an increased prevalence of bronchitis, a loose cough, reduced levels of FEV1 and FVC, and increased longitudinal changes in FEV1 and FVC. The longitudinal changes and current levels of FEV1 and FVC were not correlated with any index of firefighting exposure in active firefighters. Increased use of protective respiratory apparatus and previously described selection effects within the Boston Fire Department appear to be protecting this group of firefighters from long-term effects of smoke exposure as measured by these techniques.

Adult↗
PubMed1982

An empirical approach to the statistical analysis of mutagenesis data from the Salmonella test.

A number of recent papers have suggested basing the statistical analysis of Salmonella (Ames) mutagenicity test results on a mathematical model of the complete dose-response curve. For most mutagens at low doses the curve increases linearly; then, as the dose increases, the curve may flatten and finally turn downwards due primarily to effects of toxicity. The exact mechanism underlying this shape is, however, not well understood and is likely to vary for different chemicals. A different approach is to assume that the initial part of the curve is linear and to base the statistical analysis solely on this region, reasoning that it contains most of the interpretable information about the mutagenesis dose response. In this paper a formal method of deciding which points are on the initial linear part of the curve is described, and a statistical method is proposed for analyzing these points. Computer simulations are used to examine the properties of the procedure and comparisons are made with a previously proposed mathematical model of the whole curve. It is concluded that the method suggested here provides a very satisfactory, robust method for the standard analysis of Salmonella data.

Dose-Response Relationship, Drug↗
PubMed1982

Hypoglycemic peripheral neuropathy in association with insulinoma: implication of glucopenia rather than hyperinsulinism. Case report and literature review.

A syndrome of peripheral polyneuropathy associated with islet cell tumors and hypoglycemia has been reported in 28 patients. Despite varying features in these patients, the clinical characteristics of this syndrome are remarkably similar. These consist of the development of a sensorimotor neuropathy during a protracted course of recurrent severe hypoglycemia, related to underlying insulinoma. Cerebral symptoms dominate the clinical picture and a predominantly or entirely motor, distal and symmetric, peripheral neuropathy ensures. Upper limb involvement is more frequent, accompanied by severe weakness and distal wasting, usually without fasciculations. Painful distal paresthesias without objective sensory loss are characteristic. Direct relationship to a single hypoglycemic insult is often absent. This report describes the clinical features and laboratory investigation of a new case with this condition, reviews the literature and discusses the syndrome with special regard to the etiology.

Adenoma, Islet Cell↗
PubMed1982

Approximate confidence intervals for probabilities of survival and quantiles in life-table analysis.

For survival probabilities with censored data, Rothman (1978, Journal of Chronic Diseases 31, 557-560) has recommended the use of quadratic confidence limits based on the assumption that the product of the 'effective' sample size at time t and the life-table estimate of the survival probability past time t follows a binomial distribution. This paper shows that the proposed confidence limits are asymptotically correct for continuous survival data. These intervals, as well as those based on the arcsine transformation, the logit transformation and the log(--log) transformation, are compared by simulation to those based on Greenwood's formula--the usual method of interval estimation in life-table analysis. With large amounts of data, the alternatives to the Greenwood method all produce acceptable intervals. On the basis of overall performance, the intervals suggested by Rothman are preferred for smaller samples. Any of these methods may be used to generate confidence sets for the median survival time or for any other quantile.

Actuarial Analysis↗
PubMed1981

Estimation of the proportional hazard in two-treatment-group clinical trials.

Two easily-computed approximate methods of obtaining an estimate of the ratio of the hazard rates for two treatments in survival analysis are compared, by simulation, with the partial maximum likelihood (CML) estimator which assumes the Cox model with no covariates. The two methods studied are the Mantel-Haenszel estimator, and the O/E method which employs the ratio of the 'relative death rates' for the two treatments. Uncensored and censored cases are examined for both continuous and tied data with the assumption of either an underlying exponential distribution or a Weibull distribution with shape parameter 2. The O/E method is biased but, within the range of values of the ratio of the hazard rates of interest in clinical trials, it is more efficient in terms of mean square error than either CML or the Mantel-Haenszel method for all but the largest trials. The Mantel-Haenszel method is minimally biased, gives answers very close to those obtained using CML, and may be used to provide satisfactory approximate confidence intervals.

Clinical Trials as Topic↗
PubMed1980

Coronary artery spasm: use of ergonovine in diagnosis.

Ergonovine maleate was administered to 69 patients with chest pain but without significant coronary artery disease (less than 10% luminal diameter obstruction) to determine whether coronary artery spasm could be provoked. Coronary artery spasm was seen at angiography, or inferred from ECG or thallium myocardial perfusion scan changes. The test was positive in 16 patients: all five patients with documented variant angina (Group A); ten of the 19 patients with suspected variant angina (Group B); one of the 11 patients with exercise-induced chest pain (Group C); and none of the 34 patients with atypical chest pain (Group D). Patients with a positive test usually smoked, complained of recurrent nocturnal or early morning chest pain, showed ST changes during spontaneous chest pain and had minot degrees of fixed coronary obstruction (30--70%), when compared to those with a negative test. The only major side effect of the test was transient ventricular tachycardia which occurred in three patients and was reverted by sublingual and parenteral nitroglycerine.

Aged↗
PubMed1978

Compound frontal sinus injuries with intracranial penetration.

Extensive trauma to the forehead, resulting in large penetrating wounds of the frontal sinus that extend into the frontal lobes of the brain, has traditionally been treated by frontal sinus ablation. Although this operation eliminates dead space, it leaves the patient with a depressed area in the forehead with little protection for the brain. The success of Nadell and Kline in replacing skull fragments following compound depressed skull fractures yet avoiding infection has spurred us to attempt this technique in penetrating injuries of the frontal sinus. By preserving the anterior frontal sinus wall, we have not only afforded protection for the frontal lobes of the brain, but, at the same time, avoided the cosmetic defect that would be left by an ablation procedure. This procedure has been performed on two patients at our institution. After a two-year follow-up, excellent forehead profile preservation has been achieved and there has been no evidence of bone absorption or infection at any time since surgery.

Adolescent↗
PubMed1977

[Total protein and immunoglobulin concentrations in the parotid saliva of pregnant women].

The content of total protein and immunglobulins in the parotid saliva and blood serum of pregnant women and healthy test persons has been determined by the biuret method and radial immunofiffusion. It was stated that total protein and IgG in the parotid saliva were higher in pregnant women than in healthy test persons, whereas the IgA-levels don't show any differences. IgM was not measurable in the parotid saliva. There was no relationship between saliva and serum immunglobulins. During the pregnancy show the parotid glands another typ of reaction than nonpregnant women.

Female↗
PubMed1977

Primary acquired hypogammaglobulinemia and regional enteritis.

We had a patient with primary acquired hypogammaglobulinemia (PAH), nodular lymphoid hyperplasia, giardiasis, and the subsequent development of regional enteritis (RE). The case is of interest because the development of regional enteritis in a patient with PAH has not been previously reported, to our knowledge. The interaction of hypogammaglobulinemia and RE is discussed from an immunologic point of view. The report adds RE to the many known bowel diseases associated with PAH.

Adult↗