Biomedical subjects

L Bernstein

Publications and source records attributed to L Bernstein.

At least 235 records · Page 13Linked to original sources

PubMed1984

The clinical features of isolated left circumflex coronary artery disease.

The clinical characteristics of 84 patients with isolated circumflex disease (greater than or equal to 70% luminal stenosis) were reviewed. A total of 66 patients had angina pectoris (mean duration 17.3 months), and 60 had suffered a myocardial infarction. Risk factors averaged 2.2 per patient. In the 84 patients there were 103 discrete circumflex stenoses; 51 stenoses were central (proximal circumflex, obtuse marginal, and intermediate branches), and 52 were peripheral (distal circumflex, posterolateral, and posterior descending branches); 48 were total and 55 were subtotal. Left ventricular function was normal in 21 patients and abnormal in 63 patients, but the mean left ventricular ejection fraction of the group was normal (59 +/- 12%). Eighty-two patients had abnormal electrocardiograms: there were Q waves in 25, RV pattern in 43, ST-T wave abnormalities in 19, left bundle branch block in two, and pacemaker rhythm in one. Inferior abnormalities on the electrocardiogram correlated with peripheral stenoses (p less than .02), and lateral abnormalities on the electrocardiogram correlated with central stenoses (p less than .01). The RV pattern of true posterior infarction was seen in both central and peripheral stenoses. In the 32 patients who underwent thallium scanning, lateral defects were more common with central stenoses, but posterolateral defects occurred similarly in central and peripheral stenoses. Prognosis was good. There were two deaths during the mean follow-up time of 17 months (range 1 to 49). The cumulative survival rate was 100% at 12 months, 97.5 +/- 2.9% at 24 months, and 97.5 +/- 3.6% at 30 months.

Adult↗

PubMed1984

The TD50: a proposed general convention for the numerical description of the carcinogenic potency of chemicals in chronic-exposure animal experiments.

A generally accepted format for the numerical description of the carcinogenic potency of a particular chemical in a particular strain of animals is desirable so that statements from different sources about potency and attempts by different authors to correlate potency with particular laboratory measurements will be comparable. The choice of an appropriate standard format is to a certain extent arbitrary. In this paper we recommend that the TD50 (tumorigenic dose rate 50) be used. TD50 can be calculated for a single target site or combination of sites. The TD50, in analogy with the LD50, is defined as that chronic dose rate (in mg/kg body weight/day) which would halve the actuarially adjusted percentage of tumor-free animals at the end of a standard experiment time--the "standard lifespan" for the species. This paper consists of a brief discussion of the TD50, sufficient to make the general reader familiar with the properties of such an index, an appendix discussing methods for its estimation and certain conventions we have adopted for use in analyzing "nonstandard" experiments. A major problem in calculating any index of carcinogenic potency is that much published material gives only the final crude percentage of tumor-bearing animals at each dose, instead of percentages adjusted for the effects of intercurrent mortality or data from which these adjusted percentages can be derived. If the dose level administered to the animals is toxic, then premature death from nonneoplastic causes may prevent some dosed animals that would have developed tumors from actually doing so. This will particularly affect the high-dose group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1984

A carcinogenic potency database of the standardized results of animal bioassays.

The preceding paper described our numerical index of carcinogenic potency, the TD50 and the statistical procedures adopted for estimating it from experimental data. This paper presents the Carcinogenic Potency Database, which includes results of about 3000 long-term, chronic experiments of 770 test compounds. Part II is a discussion of the sources of our data, the rationale for the inclusion of particular experiments and particular target sites, and the conventions adopted in summarizing the literature. Part III is a guide to the plot of results presented in Part IV. A number of appendices are provided to facilitate use of the database. The plot includes information about chronic cancer tests in mammals, such as dose and other aspects of experimental protocol, histopathology and tumor incidence, TD50 and its statistical significance, dose response, author's opinion and literature reference. The plot readily permits comparisons of carcinogenic potency and many other aspects of cancer tests; it also provides quantitative information about negative tests. The range of carcinogenic potency is over 10 million-fold.

Animals↗

PubMed1984

Intact and carboxyterminal PTH do not cross the blood-cerebrospinal fluid barrier.

In order to examine whether parathyroid hormone (PTH) enters the cerebrospinal fluid (CSF), the blood levels of the hormone were acutely elevated either by infusion of parathyroid extract or by stimulation of the parathyroid glands by hypocalcemia. Despite marked elevations in the blood levels of the hormone, PTH could not be detected in the CSF. The data indicate the intact PTH or its carboxyterminal fragment do not cross the blood-CSF interface of the blood-brain barrier. The results, therefore, suggest that the action of PTH on brain must be mediated by an effect on the blood-brain interface of the blood-brain barrier.

Animals↗

PubMed1984

Parallels in the epidemiology of selected anogenital carcinomas.

Characteristics of Los Angeles, Calif., residents in whom carcinomas of the cervix, vulva, vagina, anus, and penis were diagnosed during the period 1972-81 were compared with those of all residents and with those in whom any cancer was diagnosed during the same period. At all five sites, risks for squamous and transitional cell carcinomas generally increased with decreasing social class, were low among Jews (not explained by social class), and were elevated among persons who were separated or divorced at diagnosis compared to married persons. Single men had a striking excess of anal but not penile carcinomas. The five sites represent contiguous and histologically similar tissues, and the clinical literature suggests common risk factors, e.g., sexually transmitted infections and other forms of chronic irritation. These observations are all consistent with the hypothesis that tumors at these sites have common or similar etiologic elements.

Adenocarcinoma↗

PubMed1984

Calculation of carcinogenic potency from long-term animal carcinogenesis experiments.

An index of carcinogenic potency for chemicals tested in chronic animal experiments is described. By analogy with the well-known 'lethal dose 50' (LD50) of quantal bioassay, a 'tumorigenic dose 50' (TD50) may be defined (in the absence both of tumors in the control group and of intercurrent deaths) as that (daily) dose of chemical which gives 50% of the test animals tumors by some fixed age. Tumors in the control (zero-dose) group are handled exactly as for the LD50, and intercurrent deaths are handled by life-table methods. Nonparametric procedures are developed for estimating the TD50 and for constructing confidence intervals. These are based on likelihoods which assume that the tumor hazard is linear in dose.

Aniline Compounds↗

PubMed1984

Thymidylate synthetase inhibition in malignant tumors and normal liver of patients given intravenous 5-fluorouracil.

Single surgical biopsies of solid tumor were obtained at 20 to 240 min after drug administration in 21 patients given first-dose bolus i.v. 5-fluorouracil (5-FUra), 500 mg/sq m, and assayed for 5-fluorodeoxyuridylate (FdUMP), deoxyuridylate (dUMP), total thymidylate synthetase (TS), and non-FdUMP-bound, free enzyme. Nineteen patients had cancer of gastrointestinal origin, 13 of these colorectal, and 2 patients had breast adenocarcinoma. In 9 patients, synchronous biopsies of surgically normal liver were obtained along with samples of hepatic tumors metastatic from gastrointestinal sites. Total TS averaged 4.18 pmol/g in the malignant tissues and 2.23 pmol/g in liver. FdUMP levels in the gastrointestinal tumors were higher than in normal liver, were highest at the earliest time interval studied, 20 to 30 min, and appeared to decrease exponentially through 120 min. TS inhibition averaged 70 to 80% in gastrointestinal tumor biopsies and less than 50% in normal liver. Levels of dUMP were low and varied little with time. Those gastrointestinal tumors with higher FdUMP:dUMP ratios showed significantly greater TS inhibition. Tumors of 3 patients who benefited from 5-FUra therapy (1 patient with colonic adenocarcinoma and the 2 patients with breast adenocarcinoma) showed greater TS inhibition than did tumors of remaining patients. It is concluded that the apparent time course changes observed in FdUMP, dUMP, and TS in the grouped data are qualitatively similar to findings of murine studies in vivo and that the relationship between FdUMP:dUMP ratios and TS inhibition are consistent with established in vitro enzymic kinetics. Thus, biopsies of tumors at short time periods after 5-FUra administration may be usefully studied for biochemical parameters of TS inhibition, with the objectives of correlation of sensitivity to subsequent 5-FUra therapy and clarification of mechanisms of drug resistance.

Adult↗

PubMed1983

Prognosis after an initial non-Q-wave myocardial infarction related to coronary arterial anatomy.

Eighty-six consecutive hospital survivors (aged less than or equal to 60 years) of a first non-Q-wave acute myocardial infarction (MI) were followed up prospectively. Coronary arteriography was performed a median of 2 weeks after MI. The size of the MI was small (as judged by a mean peak creatine kinase level of 906 IU/liter); 90% were in Killip class I, and the mean left ventricular ejection fraction was 60 +/- 11% (+/- standard deviation). Forty-nine patients had 1 vessel significantly narrowed by disease (greater than or equal to 70% luminal diameter reduction), 19 had 2-vessel, 2 had 3-vessel, 3 had left main (greater than or equal to 50% luminal diameter reduction), and 13 minimal or no coronary artery disease (CAD). Complete occlusion of the MI-related vessel was present in 33 patients. All 33 and an additional 5 patients had collateral vessels to the MI area. During a mean follow-up of 25 months, 1 cardiac death and 4 recurrent infarcts (3 with non-Q-wave MI) occurred. Angina occurred in 53 patients (62%) and responded medically in all but 7 who underwent coronary artery surgery. Angina after MI occurred frequently in patients with severe proximal left anterior descending CAD (greater than or equal to 90%), and in those with CAD (greater than or equal to 50%) in a vessel supplying collaterals to the infarct area. Because angina can be managed medically in most patients and the outcome is good, routine coronary angiography is not indicated in asymptomatic survivors less than or equal to 60 years of a first non-Q-wave MI.

Angina Pectoris↗

PubMed1983

Physical fitness and subsequent myocardial infarction in healthy workers.

Physical work capacity (PWC), a measure of physical fitness, was assessed by bicycle ergometry on 2,779 healthy men younger than 55 years who were subsequently followed up for an average of 4.8 years for symptomatic myocardial infarction (MI). There were 36 MIs. The relative risk (RR) of MI for below median PWC, adjusted for conventional risk factors for heart disease, was 2.2 (95% confidence limits, 1.1 and 4.7). This increased risk appeared to be limited to men with certain other risk factors present simultaneously: above-median cholesterol level, smoking, above-median systolic BP, or a combination of these. Among men with at least two of these factors, the adjusted RR for below-median PWC was 6.6 (95% confidence limits, 2.3 and 27.8). Poor physical fitness may be an important risk factor for heart disease, especially when conventional risk factors are also present.

Adult↗

PubMed1983

Acquired immunodeficiency with reversed T4/T8 ratios in infants born to promiscuous and drug-addicted mothers.

A new syndrome of acquired immunodeficiency has been identified in seven children who were small for gestational age at birth and subsequently have exhibited failure to thrive, lymphadenopathy, parotitis, hepatosplenomegaly, interstitial pneumonia, and recurrent infections. All have a profound cell-mediated immunodeficiency with reversed T4/T8 ratios. Six are hypergammaglobulinemic and one has low IgG levels. The mothers of five of the seven children are sexually promiscuous and/or drug addicts. Three mothers have an immunodeficiency similar to that found in their infants. One of them died at age 33 years with a diagnosis of acquired immunodeficiency syndrome. In five of the children and in three of their mothers, there is evidence of a persistent Epstein-Barr virus (EBV) infection. We speculate that a perinatal or in utero transmission of EBV can induce an "infectious immunodeficiency." The clinical, histopathologic, and immunologic features resemble those described in adult homosexuals and drug addicts.

Acquired Immunodeficiency Syndrome↗

PubMed1983

Aldose reductase inhibition improves nerve conduction velocity in diabetic patients.

To assess the potential role of polyol-pathway activity in diabetic neuropathy, we measured the effects of sorbinil--a potent inhibitor of the key polyol-pathway enzyme aldose reductase--on nerve conduction velocity in 39 stable diabetics in a randomized, double-blind, cross-over trial. During nine weeks of treatment with sorbinil (250 mg per day), nerve conduction velocity was greater than during a nine-week placebo period for all three nerves tested: the peroneal motor nerve (mean increase [+/- S.E.M.], 0.70 +/- 0.24 m per second, P less than 0.008), the median motor nerve (mean increase, 0.66 +/- 0.27, P less than 0.005), and the median sensory nerve (mean increase, 1.16 +/- 0.50, P less than 0.035). Conduction velocity for all three nerves declined significantly within three weeks after cessation of the drug. These effects of sorbinil were not related to glycemic control, which was constant during the study. Although the effect of sorbinil in improving nerve conduction velocity in diabetics was small, the findings suggest that polyol-pathway activity contributes to slowed nerve conduction in diabetics. The clinical applicability of these observations remains to be determined, but they encourage further exploration of this approach to the treatment or prevention of diabetic neuropathy.

Adult↗

PubMed1983

Nasopharyngeal angiofibroma presenting as adult osteomalacia: case report and review of the literature.

Unexplained osteomalacia may be the result of various neoplasma including ENT tumors. The mechanism of this oncogenic osteomalacia is uncertain, but it may result from a tumor-induced alteration in vitamin-D metabolism or from a direct phosphaturic action of a tumor product. Thorough ENT evaluation of patients presenting with unexplained osteomalacia is indicated, as successful tumor excision can lead to cure.

Female↗

PubMed1983

Coronary and left ventricular angiographic anatomy and prognosis of survivors of first acute myocardial infarction.

To relate coronary anatomy and left ventricular function to prognosis, 197 of 269 consecutive survivors of a first myocardial infarction (MI) less than or equal to 60 years old underwent prospective cardiac catheterization a median of 2 weeks after admission and were followed up for a median of 24 months (range 12 to 61). Seventy-two patients were excluded from angiography because of early death (9), severe noncoronary disease (44), MI complications (6), or patient refusal (13). The prevalence of multivessel disease was low (30%) and unrelated to the site of MI or presence of Q waves but was increased in patients with previous angina pectoris (p = 0.05) or those in Killip class II or III (p = 0.02). There were only 8 deaths from heart disease. The survival rate at 12 months was 97 +/- 1% and at 24 and 36 months, 95 +/- 2%. Nineteen patients underwent coronary revascularization surgery. As the number of deaths was small, the differences in survival between patients with single or multivessel disease and normal or depressed ejection fractions failed to reach significance. Survivors of a first MI less than or equal to 60 years old have a low prevalence of multivessel disease and a good prognosis.

Adult↗

PubMed1983

Mandibular growth, condyle position and Fränkel appliance therapy.

A statistical evaluation of condyle position and mandibular length changes in 10 patients after one year of Fränkel appliance therapy, finding the condyle forward on the eminence in 4 of them. Large variations were found in mandibular growth, with no significant difference from the means of patients treated with the Edgewise appliance.

Activator Appliances↗

PubMed1983

UCLA hospice evaluation study. Methodology and instrumentation.

An unbiased evaluation of hospice effectiveness requires a randomized controlled trial (RCT), but the implementation of such a design is difficult. This paper describes the methods of the only RCT to date and reports on the validity and reliability of scales selected or developed to assess attainment of hospice goals. The patients involved are those in a VA hospital in Los Angeles who have cancer and a prognosis of about 6 months and who consent. They and their significant others are interviewed periodically until the patient's death to measure such hospice variables as pain, depression, anxiety, satisfaction with care and the environment, activities of daily living, and bereavement effects. Many of the scales, including McGill Pain, CES-D Depression, and Satisfaction with Care scales, have been validated in other studies with similar samples. The authors' test-retest reliability analyses show that these scales are reliable with advanced cancer patients and their significant others with coefficients ranging from 0.77 to 0.97.

California↗

PubMed1983

Geometric determination of left ventricular volume from gated blood-pool studies using a slant-hole collimator.

A geometric method of measuring absolute left ventricular volumes from gated blood-pool studies obtained in a single-plane modified left anterior oblique view was evaluated prospectively in 30 patients who also underwent single-plane contrast ventriculography. The gated studies used a 30 degrees straight-bore slant-hole collimator with the holes slanted caudally. Left ventricular end-diastolic volume was calculated using the area-length method, with semiautomatic definition of the left ventricular region of interest and the maximum length of the left ventricle. Ejection fraction was determined from the left ventricular time/activity curve. The left ventricular end-systolic volume was derived using the end-diastolic volume and ejection fraction. Correlation coefficients between the two methods were 0.93 for end-diastolic volume, 0.95 for end-systolic volume, and 0.91 for ejection fraction. This method provided accurate and highly reproducible measurements of actual left ventricular volumes and was easily applicable in routine clinical studies.

Adult↗

PubMed1983

Coronary anatomy and prognosis after myocardial infarction in patients 60 years of age and younger.

Two hundred twenty-nine hospital survivors of acute myocardial infarction (MI) age 60 years or younger underwent coronary arteriography a median of 2 weeks after infarction and were followed a median of 24 months (range 6-62 months). For 62%, MI was the first presentation of coronary disease and 75% were in clinical Killip class I. Overall outcome was good: 96% survival at 1 year and 95% survival at 2 years. This was due to the high prevalence of patients with one-vessel disease (58%), with a survival of 99% at 1 year and 96% at 2 years. Only 9% of patients had three-vessel disease and they had an 85% survival at 1 year. Eleven patients died and 23 had coronary bypass surgery. In this cohort of younger patients (mean age 51 years), prophylactic therapy may not be justified because of the low mortality and should be reserved for identifiable high-risk groups.

Adult↗

PubMed1982

Replanting the severed auricle. An update.

An updated method of replanting a severed auricle is reported. Management consists of early, meticulous replantation with minimal debridement; cooling of the auricle; low-dose heparin sodium; dextran 40; antibiotic coverage; and multiple stab incisions to relieve venous congestion. The regimen is based on experience with nine successfully replanted auricles.

Adult↗