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Biomedical subjects

M Fay

Publications and source records attributed to M Fay.

At least 91 records · Page 5Linked to original sources

Preincubation of thyroxine with sulfhydryl-reducing agents does not stimulate thyroxine inner or outer ring deiodination.

Sulfhydryl reagents stimulate enzymatic conversion of T4 to T3 and rT3. A recent study suggested that such reagents stimulated T4 5'-deiodination by a direct interaction with T4. We therefore tested the ability of dithiothreitol (DTT) and other sulfhydryl reagents to enhance the susceptibility of T4 and rT3 to 5'-deiodination by liver homogenates and of T4 to 5-deiodination by placental homogenates. Preincubation of T4 with DTT in concentrations ranging from 0.5-80 mM did not result in increased T3 production from T4 in rat liver homogenates, nor was T3 production increased by preincubation of T4 with reduced glutathione or mercaptoethanol. Preincubation of rT3 with DTT also did not result in increased rT3 degradation by liver homogenates. T4 5-deiodination to rT3 by rat and human placental homogenates was not consistently increased by preincubation of T4 with DTT in concentrations ranging from 2.25-450 mM. These results do not support the hypothesis that sulfhydryl stimulation of T4 deiodination occurs as a result of sulfhydryl-T4 interaction.

Animals↗

Surgical therapy for Prinzmetal's variant angina.

Fifty-two patients underwent coronary artery bypass grafting between 1973 and 1979 for variant angina, defined as pain, usually at rest, associated with S-T segment elevation. Only patients with fixed occlusive coronary artery disease, defined as greater than 70% narrowing in diameter, were included. When fixed coronary artery stenosis is present, variant angina--whether presenting as stable, unstable, or postinfarction angina, and regardless of the number of vessels diseased--is effectively treated by myocardial revascularization. Preoperative intraaortic balloon pumping is a useful therapeutic adjunct in the unstable subset refractory to medical therapy. The results of revascularization in patients with Prinzmetal's variant angina and fixed coronary disease were no different from those in patients with classic angina pectoris of comparable clinical categories.

Adult↗

[Effect of a histamine aerosol in 20 subjects with histamine hyperreactivity. Application to a study of the protective properties of pipoxizine].

The authors made a study of the antihistaminic properties of Pipoxizine in 20 subjects with proven histaminic hyperreactivity. The design of the trial consisted in comparing the changes of VC, FEC1, expiratory airway resistance and V50 produced by a histamine aerosol given before and after administration of Pipoxizine. Pipoxizine was given by mouth to 10 patients and intravenously to the other 10 of the group. The statistical analysis of the results demonstrated an antagonist effect of Pipoxizine on the histamine induced bronchoconstriction. The data of this trial are confirmative of the results of other experimenters. It seems therefore reasonable to take into consideration the use of Pipoxizine in the preventive treatment of the paroxystic attacks of the asthmatic disease.

Aerosols↗

Changes of P50 in hypoxaemia, hypercapnia and polycythaemia: multivariate analysis.

Multivariate analysis of P50 changes in hypoxia, hypercapnia and polycythaemia was performed in an heterogeneous group of forty three patients: hypoxic subjects with or without hypercapnia, with or without polycythaemia and polycythaemic subjects without hypoxia. A statistical analysis was undertaken using comparison of the means, study of the correlations, principal component analysis, multiple regression and correspondence analysis. In the patients studied, P50 changes were not wholly explained by those of 2-3 DPG and pH; PaCO2, per se, did not play an important part. Haemoglobin concentration and P50 value would represent an adaptative mechanism to hypoxia: when hypoxia is moderate (80 greater than PaO2 greater than or equal to 65 torr) and isolated, oxygen haemoglobin affinity decreases (P50 increases); when hypoxia is severe (PaO2 less than 65 torr) and combined with hypercapnia and disturbed acid-base equilibrium, P50 comes back to normal range but haemoglobin increases, restoring thus, the normal blood oxygen content.

Adult↗

[Measurement of the oxygen affinity of hemoglobin. Application to patients with angina pectoris with normal coronography. Study of 10 cases].

A study of 2-3 D.P.C. (diphosphoglycerate) and of P50 (PO2 of half-saturation of blood at pH 7.40, PCO2 40 torr and temperature 37 degrees C) was carried out in ten subjects: eight women and two men suffering from angina pectoris with no evidence of obstruction on their coronary arteriograms. The study was made with the subjects at rest, in the absence of any acute coronary episode. The results show that these patients have a normal affinity of haemoglobin for oxygen: the 2-3 D.P.G. was 13.05 +/- 2.2 muM.g-1 Hb; P50 was 26.7 +/- 1.3 torr; Hill's "n" was 2.65 +/- 0.29. Deviation to the right of the oxyhaemoglobin curve may be seen, after effort or during a provoked attack, but this movement to the right seems to be the result rather than the cause of the myocardial ischaemia.

Adult↗

Public health assessment of hexachlorobenzene.

Recently, hexachlorobenzene (HCB) was proposed for inclusion in the system of toxicity equivalency factors (TEFs) currently used for dioxin-like compounds. In this paper, we explore the practical implications of the proposition to the Agency for Toxic Substances and Disease Registry (ATSDR) programs by comparing respective health guidance values for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and HCB (expressed as total toxicity equivalents [TEQs]), reviewing possible interactions between HCB and dioxin-like chemicals, and by providing information on actual co-existence of HCB and dioxin-like chemicals at hazardous waste sites. We found a good correlation between the TEF-adjusted oral exposure guidance values for HCB and guidance values for TCDD. The combination of HCB and other dioxin-like compounds was not found in soil, air, or water media at hazardous waste sites. Based on this fact, it is not necessary to include HCB in the total TEQ count at hazardous waste sites at this time.

Drug Interactions↗

Public health implications of hazardous waste sites: findings, assessment and research.

In this paper we present an overview of the chemicals released from hazardous waste sites (HWS) and some of the mixtures of substances that have been released into environmental media. We describe how this information can be used to assess the public health hazard of releases of chemical mixtures from waste sites. Wherever possible, research on chemical mixtures should use chemical mixtures actually identified in, or representative of, mixtures in environmental media. A narrative, weight-of-evidence approach to characterize the toxicity of mixtures that incorporates mechanistic insights on chemical interactions is described. The utility of this information in the context of risk analysis and public health practice is discussed.

Animals↗

ATSDR evaluation of health effects of chemicals. V. Xylenes: health effects, toxicokinetics, human exposure, and environmental fate.

Xylenes, or dimethylbenzenes, are among the highest-volume chemicals in production. Common uses are for gasoline blending, as a solvent or component in a wide variety of products from paints to printing ink, and in the production of phthalates and polyester. They are often encountered as a mixture of the three dimethyl isomers, together with ethylbenzene. As part of its mandate, the Agency for Toxic Substances and Disease Registry (ATSDR) prepares toxicological profiles on hazardous chemicals found at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) National Priorities List (NPL) sites that are of greatest concern for public health purposes. These profiles comprehensively summarize toxicological and environmental information. This article constitutes the release of the bulk of this profile (ATSDR, 1995) into the mainstream scientific literature. An extensive listing of known human and animal health effects, organized by route, duration, and end point, is presented. Toxicological information on toxicokinetics, biomarkers, interactions, sensitive subpopulations, reducing toxicity after exposure, and relevance to public health is also included. Environmental information encompasses physical properties, production and use, environmental fate, levels seen in the environment, analytical methods, and a listing of regulations. ATSDR, as mandated by CERCLA (or Superfund), prepares these profiles to inform and assist the public.

Animals↗

Learning disabilities. Community homes: institutions in waiting?

This article explores the assumption that community care is better than care in an institution for people with learning disabilities. Parallels are also drawn with community provision of residential and nursing home accommodation for people who are elderly, those who have a physical handicap, and people with a mental illness. While community care is recognised as a valuable option, the authors argue that it must be correctly implemented, and identify the need to move further forward.

Community Mental Health Services↗