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Biomedical subjects

M Finkelstein

Publications and source records attributed to M Finkelstein.

At least 37 records · Page 2Linked to original sources
PubMed1986

Pulmonary function in asbestos cement workers: a dose-response study.

This study has found that residence time weighted exposure (asbestos dose) may be used to model the risk and extent of pulmonary function abnormalities in a cohort of asbestos cement workers. This parameter, which incorporates both exposure concentration and latency, had previously proved useful for modelling the risk of radiographic abnormalities in this cohort. Asbestos dose and smoking were independent and additive contributors to decreased pulmonary function. It was also found that lung function results could be used as surrogates for dose in the assessment of mortality risk in this cohort.

Adult↗
PubMed1985

The assessment of risk factors in 462 patients with acute renal failure.

Risk factors associated with the mortality of patients with acute renal failure (ARF) were investigated. This was accomplished by a review of 462 patients with ARF and the utilization of a logistic regression analysis to develop a model that can be used to predict the mortality odds for an ARF patient. The significant risk factors were age, oliguria, pulmonary and cardiovascular complications, jaundice, and hypercatabolism. Based on these factors, our model was able to account for 77% of the mortality associated with ARF.

Acute Kidney Injury↗
PubMed1985

Esophageal duplication in children: a report of three cases evaluated by computed tomography.

Primary tumors of the esophagus are extremely rare in children. A common periesophageal mass in children is duplication. It constitutes only 0.5 to 2.5% of all esophageal lesions usually diagnosed in infancy or early childhood. Duplication of the esophagus may be diagnosed on examination by the emergency department (ED) physician when it produces symptoms or when it is inadvertently found on a chest radiograph. The duplication may produce acute gastrointestinal symptoms such as vomiting and dysphagia or respiratory symptoms such as cough, wheezing, or dyspnea. Currently the examination of choice for evaluation of esophageal duplication is a barium swallow. However, computed tomography (CT) has the advantage over conventional diagnostic procedures, since it demonstrates the cystic nature of the mass and its relationship to adjacent structures in a noninvasive manner. An esophageal duplication has a well-marginated spherical mass contiguous with the esophagus, with preserved surrounding fat planes, and numbers of 15 to 30 Hausenfield units (HU) on CT. We are reporting three cases of this anomaly as demonstrated by CT.

Adolescent↗
PubMed1983

Apparent double defect in C11 beta and C21-steroid hydroxylation in congenital adrenal hyperplasia.

Some patients with either fully developed, mild or even hidden forms of congenital adrenal hyperplasia have both 21-deoxycortisol and increased 11-deoxycortisol in their blood and excrete "pregnanetriolone" and "tetrahydro-S" in their urine. The simultaneous presence of these compounds suggests two enzymic deficiencies, which are expressed in C21- and C11 beta-hydroxylases, respectively. However, these deficiencies have been inferred to derive from a single aberration in C11 beta-hydroxylase, whereby the enzyme acquires an affinity towards 21-deoxy precursors (i.e. 17-OH-progesterone) of cortisol and diminishes its activity against its regular 21-hydroxy intermediate 11-deoxycortisol. Depending on the severity of the aberration varying amounts of 21-deoxycortisol (expressing the aberrant 11 beta-hydroxylase) and of 11-deoxycortisol (expressing the normal 11 beta-hydroxylase) will be formed. An apparent two-level inhibition of cortisol biosynthesis will result from: (1) the low activity of normal 21-hydroxylase on the derivative 21-deoxycortisol, produced by the action of the aberrant 11 beta-hydroxylase, and (2) the low supply of 11-deoxycortisol for the regular but decreased (due to the aberration) 11 beta-hydroxylase. Thus a single defect will mimic at one and the same time a 21-hydroxylase and a 11 beta-hydroxylase deficiency.

Adolescent↗
PubMed1982

Mortality among miners receiving workmen's compensation for silicosis in Ontario: 1940-1975.

We investigated mortality among 1,190 Ontario miners who received Workmen's Compensation awards for silicosis from 1940 through 1975. In comparison with the general population of Ontario these men had elevated all-cause mortality rates, with deaths attributed to nonmalignant respiratory diseases and tuberculosis being primarily responsible. The group of miners receiving their compensation awards between 1940 and 1959 has experienced more than twice as many lung cancer deaths as expected while men receiving compensation awards after 1959 have had lung cancer rates similar to the general population. It is concluded that silicosis is not a benign disease and that efforts must be continued to prevent its occurrence.

Adult↗
PubMed1981

Mortality among workers receiving compensation for asbestosis in Ontario.

Mortality among 172 workers who received workmen's compensation for asbestosis in Ontario was investigated and the causes of death were compared with those for the general male population in that province. The workers were found to have increased rates of death, relative to the general populations, for nonmalignant respiratory diseases, lung cancer and pleural and peritoneal mesothelioma. In comparison with the general population, the proportion of workers that survived was 69% of that expected 5 years after they were awarded compensation and 53% at 10 years.

Adult↗
PubMed1981

Comparative studies of the aromatization of testosterone and epitestosterone by human placental aromatase.

The aromatization of epitestosterone (17 alpha-hydroxy-4-androsten-3-one) and testosterone by lyophilized human placental microsomes was studied. Upon incubation of epitestosterone, 12% was converted to 17 alpha-estradiol, 15% to 19-keto-epitestosterone (17 alpha-hydroxy-4-oxo-4-androsten-19-al), 10% to 19-hydroxyepitestosterone (17 alpha, 19-dihydroxy-4-androsten-3-one), and about 10% to several unidentified products. A similar incubation with testosterone resulted in 60% conversion to 17 beta-estradiol; 30% was unchanged. At increasing substrate concentrations (0.1-50 microM), the aromatization rate of epitestosterone increased gradually and did not reach a plateau, whereas aromatization rate of testosterone plateaued at about 3 microM. The presence of either testosterone or 17 beta-estradiol in concentrations 0.1-10 times the concentration of epitestosterone inhibited the aromatization of epitestosterone by about 70%, while the aromatization of testosterone was not inhibited by either epitestosterone or 17 alpha-estradiol. Lyophilization of fresh microsomes or storage of the lyophilized microsomes at -20 C greatly reduced the aromatizing activity upon epitestosterone but not upon testosterone. These results suggest that the aromatizing system for epitestosterone is different from that for testosterone.

Aging↗
PubMed1978

Comparison of large unilamellar vesicles prepared by a petroleum ether vaporization method with multilamellar vesicles: ESR, diffusion and entrapment analyses.

Large unilamellar vesicles, prepared by a petroleum ether vaporization method, were compared to multilamellar vesicles with respect to a number of physical and functional properties. Rotational correlation time approximations, derived from ESR spectra of both hydrophilic (3-doxyl cholestane) and hydrophobic (3-doxyl androstanol) steroid spin probes, indicated similar molecular packing of lipids in bilayers of multilamellar and large unilamellar liposomes. Light scattering measurements demonstrated a reduction in apparent absorbance of large unilamellar vesicles, suggesting loss of multilamellar structure which was confirmed by electron microscopy. Furthermore, large unilamellar vesicles exhibited enhanced passive diffusion rates of small solutes, releasing a greater percentage of their contents within 90 min than multilamellar vesicles, and reflecting the less restricted diffusion of a unilamellar system. The volume trapping capacity of large unilamellar vesicles far exceeded that of multilamellar liposomes, except in the presence of a trapped protein, soy bean trypsin inhibitor, which reduced the volume of the aqueous compartments of large unilamellar vesicles. Finally, measurement of vesicle diameters from electron micrographs of large unilamellar vesicles showed a vesicle size distribution predominantly in the range of 0.1--0.4 micron with a mean diameter of 0.21 micron.

Chromates↗
PubMed1977

Cell cycle analysis of F'lac replication in Escherichia coli B/r.

The timing and control of replication of an F'lac plasmid was investigated in two substrains of Escherichia coli B/r lac/F'lac growing at a variety of rates. The cellular content of covalently closed circular F'lac deoxyribonucleic acid and the cellular mass at the time of F'lac replication both increased as a function of growth rate. The timing of plasmid replication during the division cycle was determined by measuring the inducibility of beta-galactosidase in cells of different ages in exponentially growing cultures. At all growth rates, the rate of induced beta-galactosidase synthesis increased in a step-wise fashion during the division cycle, indicating that the F'lac plasmid replicated at a discrete time in the cycle. At growth rates greater than one doubling per h, the cell age at F'lac replication was indistinguishable from the cell age at chromosomal lac+ replication in an isogenic F- parent. The ratio of plasmids to chromosomal origins decreased from about 0.7 to 0.4 between growth rates of 1.0 to 2.5 doublings per h. These observations are all consistent with replication of F'lac at about the same time in the division cycle as replication of the homologous chromosomal region at these growth rates. This similarity in timing of replication of homologous deoxyribonucleic acid regions was not evident in slower-growing cells.

Cell Division↗