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Biomedical subjects

A Cohen

Publications and source records attributed to A Cohen.

At least 829 records · Page 46Linked to original sources
PubMed1983

Methadone plasma levels and persistent drug abuse in high dose maintenance patients.

Methadone maintenance patients who maintained on a high daily dose were divided into good performers and poor performers based on whether they demonstrated persistent use of heroin, non-prescription diazepam, and/or excessive alcohol consumption. Mean methadone plasma levels 24 hours after an oral dose of 80 mg were found to be 410.4 ng/ml in good performers compared to 101.8 ng/ml in poor performers (P less than .05). Seven of nine (77.8%) poor compared to two of 15 (13.3%) good performers had 24-hour methadone plasma levels under 50 ng/ml (P less than .01). High dose methadone patients who show evidence of persistent drug or alcohol abuse should have their 24-hour methadone plasma level determined to help assess whether the patient should receive more methadone or find an alternative treatment.

Alcohol Drinking↗
PubMed1983

Arterial inflammatory-cell infiltration in Crohn's disease.

Histologic sections from 70 cases of Crohn's disease were studied for the presence of acute and/or chronic inflammatory cells in the walls of arteries and arterioles. Vessels in areas of marked inflammation were not considered. Similarly, arteries showing chronic obliterative changes, without inflammatory cells, were excluded. More than 20% of the cases showed either chronic inflammatory-cell infiltration, acute and chronic inflammatory-cell infiltration, obliterative changes with inflammatory-cell infiltration, or granulomatous inflammation. These changes need to be recognized as a part of Crohn's disease; furthermore, physicians should refrain from designating patients as having one of the primary vasculitides in the absence of extraintestinal evidence of disease.

Arteries↗
PubMed1982

Evidence for active purine nucleoside cycles in human mononuclear cells and cultured fibroblasts.

Several aspects of purine metabolism were studied in peripheral blood mononuclear cells and fibroblasts from a patient with purine nucleoside phosphorylase deficiency and compared to cells from normal controls. Intact cells were incubated with radioactive purine bases and all purine metabolites were extracted and analyzed. Incubation of purine nucleoside phosphorylase-deficient cells with [3H]hypoxanthine and [3H]guanine resulted in the accumulation of large proportions of the incorporated radioactivity into inosine (60-80%) and to lesser extent into guanosine (15-30%), respectively, whereas normal cells accumulated only minor amounts of inosine and guanosine. This observation indicates that purine nucleoside phosphorylase, together with hypoxanthine-guanine phosphoribosyltransferase and nucleoside monophosphate phosphatase, participate in remarkably active inosine and guanosine cycles. These purine nucleoside cycles may play a role in the regulation of intracellular purine nucleotide levels. The absence of these cycles in purine nucleoside phosphorylase-deficient patients may be detrimental to the differentiation of lymphocytes.

Cells, Cultured↗
PubMed1982

Intraoperative irradiation: a pilot study combining external beam photons with "boost" dose intraoperative electrons.

Intraoperative "boost" dose electron beam therapy given in combination with 4500--5000 rad (45--50 Gray) external beam irradiation has been demonstrated as a practical therapeutic modality at the MGH. This procedure has been employed thus far in 58 patients; the results in the initial 36 are analyzed in detail in this paper. Thirty-four of the 36 patients had locally advanced lesions--unresectable, recurrent, or residual disease. Results achieved to date are in full agreement with our expectations: high radiation doses have been delivered to the primary intra-abdominal and pelvic tumors, excluding the sensitive structures from irradiation. This has been accomplished by a truly multidisciplinary effort comprising surgery, anesthesiology, OR nursing, administration, engineers, physicists, therapy technologists, and radiation therapists. Although follow-up is not yet sufficient to judge ultimate efficacy, acute and chronic severe morbidity is low and local control is good. There is justified enthusiasm for continuing the procedure.

Female↗
PubMed1982

The accurate determination of serum glucose by isotope dilution mass spectrometry--two methods.

Two isotope dilution mass spectrometric methods have been developed for the determination of D-glucose in human serum. Each uses a uniformly labeled (13C)glucose as the internal standard. The first method involves conversion of glucose into 1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose and an extensive clean-up, followed by quantitation using packed column gas chromatography mass spectrometry. In the second method, glucose is converted into alpha-D-glucofuranose cyclic 1,2:3,5-bis(butylboronate)-6-acetate. The wet chemistry work-up is simpler, but analysis by capillary gas chromatography mass spectrometry is required. Both methods exhibit excellent precision (coefficients of variation less than 0.3%) and provided mean values that agree within 1% for all serum pools tested.

Blood Glucose↗
PubMed1982

Degradation patterns and intermediates in the anaerobic digestion of glucose: experiments with 14C-labeled substrates.

A mineral salts medium containing 1% (w/v) glucose was subjected to anaerobic digestion in an upflow reactor. Performance with respect to utilization of glucose was monitored by collection of fermentation gases and calculation of carbon mass balances. Sub-samples of bacterial suspensions from the upflow reactor were incubated with (U-14C)-glucose, (U-14C)-acetate, (2-14C)-propionate, (1-14C)-butyrate or 14C-carbonate. Individual radioactive products in samples from incubation mixtures were analysed by radio gas chromatography. Quantitatively, acetate and propionate were the only important intermediates in glucose degradation by glucose-adapted sludge, with acetate accounting for the largest part of intermediary fatty acid flux.

Acetates↗
PubMed1982

Rubella virion polypeptides: characterization by polyacrylamide gel electrophoresis, isoelectric focusing and peptide mapping.

Four polypeptides with molecular weights of 55 K, 47 K, 45 K, and 33 K have been resolved by polyacrylamide gel electrophoresis of immune precipitated rubella virus. The 47 K and 45 K components have similar peptide maps but different isoelectric points so that the same polypeptide may exist in more than one charged form. The 55 K and 45 K components have similar isoelectric points but different peptide maps showing that similarity of isoelectric point is not evidence of identity.

Electrophoresis, Polyacrylamide Gel↗
PubMed1982

Extraction of cell-associated varicella-zoster virus DNA with triton X-100-NaCl.

Varicella-zoster virus (VZV) DNA was extracted from infected cells with 0.25% Triton X-100-0.2 M NaCl and purified by isopycnic centrifugation in CsCl. In each of eight experiments, 1.8-9.8 micrograms VZV DNA was obtained from 107 infected cells. The VZV DNA obtained by this procedure had a molecular weight of 88-100 x 106 as determined by sucrose gradient sedimentation and electron microscopy, and cleavage patterns after digestion with four restriction enzymes that corresponded to patterns previously described with six strains of VZV; the pattern of BamHI-cleaved Triton-NaCl-extracted VZV DNA was identical to the pattern seen after DNA extraction from virions. These studies expand the usefulness of Triton X-100-NaCl for extraction of large molecular weight viral DNA from a system where considerable cell-free virus is produced (Pignatti et al., 1979, Virology 93, 260) to a system known for its marked cell association.

Animals↗
PubMed1982

The primary medical care practitioner's attitudes toward psychiatry. An Israeli study.

General practitioners are important to the delivery of mental health care because they perform three important functions, as an identifier, as a referral agent and as a caregiver. This study investigates the importance of the attitudes G.P.s hold on their performance of two of these functions, screening and referring. Relying on items developed in previous investigations, four measures of attitudinal dimensions are developed using factor analysis: Belief in Psychogenesis, Psychiatric Fatalism, Referral Reluctance and G.P. as Caregiver. These attitude dimensions are then related to the functions of screening and referral. Three major findings emerge from the results. First, the attitudinal dimensions uncovered are empirically distinct, suggesting that no single pro-to-anti psychiatry is present. Second, attitudes play a role in the screening of cases. A G.P. is more likely to identify cases if he believes in the psychogenesis of physical disorders, and is not concerned that identification and referral will lead to negative consequences for the patient. Third and finally, attitudes do not play a strong role in the referral of cases once they have been identified as such. The findings are presented and interpreted by referring to the sensitive position G.P.s occupy between the public and the psychiatrist.

Adult↗
PubMed1982

cDNA recombinant plasmid complementary to mRNAs for light chains 1 and 3 of mouse skeletal muscle myosin.

A recombinant plasmid with a cDNA sequence transcribed from mouse skeletal muscle RNA is shown to hybridize with mRNAs for myosin light chains LC1F and LC3F. The inserted fragment corresponds exclusively to the 3'-noncoding region of the mRNA. It hybridizes almost exclusively with the two light chain messengers from fast skeletal muscle RNA of adult mouse. Slight hybridization is seen with RNA from heart muscle and embryonic skeletal muscle. The implications of the conservation of the 3'-noncoding regions between the two mRNAs are discussed.

Animals↗
PubMed1982

Two-dimensional echocardiography in predicting left ventricular wall motion abnormalities and left ventricular function.

In an attempt to formulate a reliable noninvasive method of detecting segmental wall motion disturbances, we examined 25 patients with coronary artery disease by two-dimensional echocardiography (2-DE), standard 12-lead electrocardiography (ECG), and biplane left ventriculography. The 2-DE technic predicted qualitative wall motion abnormalities as defined by ventriculography with a sensitivity of 88% and a specificity of 86%. The ECG (Q waves) predicted segmental wall motion disturbances with only 50% and 51% sensitivity and specificity, respectively. Extrapolating the advantages of 2-DE to the assessment of global myocardial function, left ventricular wall motion index (LVWMI) and E-point septal separation (EPSS) by 2-DE were correlated with left ventriculographic ejection fractions; r values were high (.73 and -.76, respectively) in both instances. Thus, 2-DE provides a reliable noninvasive technic by which both regional and global myocardial wall motion disturbances can be assessed. Unlike previous noninvasive methods, the 2-DE results compared very favorably with those of biplane left ventriculography.

Cineangiography↗