Biomedical subjects
M Ray
Publications and source records attributed to M Ray.
Gas chromatography mass spectrometry computer analysis of volatile halogenated hydrocarbons in man and his environment--A multimedia environmental study.
As part of a study to make a comparative analysis of selected halogenated compounds in man and the environmental media, a quantitative gas chromatography mass spectrometric analysis of the levels of the halogenated compounds found in the breath, blood and urine of an exposed population (Old Love Canal area, Niagara, New York) and their immediate environment (air and water) was undertaken. In addition, levels of halogenated hydrocarbons in air samples taken in the general Buffalo, Niagara Falls area were determined.
Treatment of angina at rest with nifedipine: a short-term controlled study.
The effectiveness of nifedipine in treating angina pectoris at rest was evaluated in 14 patients with frequent ischemic episodes associated with S-T segment elevation or depression. The trial consisted of (1) a 48 hour control period; (2) a placebo period and a period of treatment with nifedipine of 48 hours each; and (3) a second placebo period and a second period of treatment with nifedipine of 24 hours each. The efficacy of treatment was evaluated by continuous electrocardiographic recording to detect painless ischemic episodes. During coronary angiography coronary spasm was demonstrated in five patients. The ergonovine maleate test was positive in seven of eight patients. No statistically significant difference was found in the mean daily number of ischemic episodes between the control period and the first placebo period, or between the control and the second placebo periods. Nifedipine produced a highly significant reduction in the mean daily number of episodes compared with the response to placebo during the first as well as the second period. Nifedipine is effective in angina at rest caused by coronary arterial spasm. The prevention of ischemia may be related to the ability of nifedipine to decrease calcium-dependent coronary muscle tone and to prevent coronary spasm.
Investigations of the 1978 epidemic of encephalitis in Asansol, West Bengal and Dhanbad, Bihar.
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Partial trisomy 8 mosaicism with 46,XX/46,XX-8,+dic(8).
We report a girl with partial trisomy-8 mosaicism whose clinical findings were those of the Warkany et al. (1962) [17] or trisomy 8 syndrome. A dicentric autosome, dic(8) (qter leads to p21::p21 leads to qter), was found in all abnormal cells and evidence is presented that one centromere was inactive, allowing the dicentric to behave as a monocentric chromosome. The parents had normal karyotypes.
Interstitial deletion of the long arm of chromosome 10.
A patient who had a karyotype 46,XY, del (10) (q11q21) is reported. The clinical findings in this boy included significant development delay and what appeared to be a combination of positional deformities and minor anomalies.
Nucleolar organizing regions of human chromosomes.
Silver-stained cells from 49 parents with a history of several abortions were compared with cells from 35 parents with normal liveborn children. The modal and mean number of silver-stained NORs (Ag-NORs) observed on D- or G-group chromosomes was similar in both groups and between males and females. Ag-NORs were randomly distributed on all five acrocentric pairs. The distribution and size of Ag-NORs within an individual was not random and was fairly consistent from cell to cell. The mean number of associations per cell was similar in both males and females of the abortion group and was less than the number of associations in controls. The probability of D- or G-group chromosomes being associated was near the expected probability of 0.6 for D-association and 0.4 for G-association. The frequency of association of any chromosome combination did not differ statistically from the expected values, though the number of associations, 15/22, was higher than expected.
[Nitroglycerin ointment in spontaneous angina pectoris. Short-term observations].
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Paroxysmal atrioventricular tachycardia involving an anomalous pathway with antegrade unidirectional block.
37 consecutive patients with frequent episodes of palpitation and/or dizziness underwent electrophysiological study. They had no signs of ventricular preexcitation during either sinus rhythm or atrial pacing. In 17 (46%), the supraventricular tachycardia was sustained by a reentry mechanism involving an anomalous AV pathway with unidirectional antegrade block (AV tachycardia). Some findings were accepted to demonstrate the existence of the anomalous pathway (AP) and others, its participation in the reentry circuit. The possible location of the AP was established in 15 cases at the following sites: left lateral in 5 cases, left posterior in 5 cases, left posteromedial in 1 case, right posterior in 1 case, right anterior in 1 case, posterior septal in 1 case, and anterior septal in 1 case. The rate of the AV tachycardia can be influenced not only by the ventriculoatrial interval but also by the other pathways included in the reentry circuit. It may change conspicuously in cases with dual AV pathway and anomalous AV pathway in relation to the modality of antegrade conduction by the AV node.
[Tricuspid insufficiency caused by papillary muscle rupture in acute myocardial infarct. Description of a case].
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Nucleolar organizing regions of normal Chinese hamster and CHW cell line chromosomes.
The chromosome preparations from fibroblasts of normal male and female Chinese hamsters and the cell line CHW were stained with AgNO3. The silver stain was usually localized at the telomeres of autosomes. The marker chromosome M1 in the CHW cell line has Ag-NOR near the centre of the long arm, which indicates that either the long arms of two number 5 chromosomes fused at the telomeres or the intact telomeric region of one chromosome fused with one with a deleted telomere. The variation of Ag-NORs' number per cell and Ag-heteromorphism in chromosome number 4 were observed. The Ag-NORs of chromosome number 4 and 5 are in approximately the same position as the positive C-bands and these may play a role in the preservation of heterochromatin.
[Cardiac insufficiency in acute myocardial infarct].
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[Right ventricular dysfunction in acute myocardial infarct].
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[Unfavorable effects of methylprednisolone in acute myocardial infarct].
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UDPglucose 4-epimerase from Saccharomyces fragilis: asymmetry in allosteric properties leads to unidirectional catalysis.
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UDP-glucose 4-epimerase from Saccharomyces fragilis. Involvement of sulfhydryl group(s) at the active site.
UDPglucose-4-epimerase (EC 5.1.3.2) from Saccharomyces fragilis is inactivated by 0.1 mM 5,5'-dithiobis-(2-nitrobenzoate) in 6 min. Unlike p-chloromercuribenzoate-inactivated or heat-inactivated enzymes, the dithiobisnitrobenzoate-inactivated enzyme retains the dimeric structure and NAD is not dissociated from the protein moiety. Inactivation of the enzyme by dithiobisnitrobenzoate can not therefore be attributed to any subsequent loss of structural integrity or to the detachment of the cofactor from the apoenzyme. The inactivated enzyme can be almost fully reactivated in the presence of mercaptoethanol and characteristic properties of native enzyme are regained. The inactivation by dithiobisnitrobenzoate can be substantially protected by UDPglucose or UDPgalactose indicating a possible critical involvement of one or more sulfhydryl groups at the active site.
Analysis of DNA replication patterns of human fibroblast chromosomes: the replication map.
A replication map of human fibroblast chromosomes from two diploid human female fibroblast lines, 46,XX and 46,X, del (X)(q13), was determined using the 'fluorescent plus Giemsa' (FPG) technique. Each chromosome was found to stain homogeneously dark when thymidine was incorporated for the entire S phase of that particular cell. As the duration of exposure to thymidine progressively decreased by increasing the incubation time in bromodeoxyuridine, the staining intensity of chromosomes decreased and, concurrently, gaps in the staining began to appear. These gaps coincide with R bands and represent the earliest areas to complete DNA synthesis. As these areas widen and increase in frequency, first Q and G bands appear, and finally C bands. Homologous X chromosomes were easily differentiated by either a comparison of the bands present or their staining intensity. The replication kinetics of the structurally abnormal heterocyclic X chromosome were very similar to those of the normal heterocyclic X chromosome. The X chromosome with deletion of a portion of the long arm was consistently late in replication.