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Biomedical subjects

R Cohen

Publications and source records attributed to R Cohen.

At least 343 records · Page 19Linked to original sources
PubMed1991

Lipolytic and ketogenic fluxes in human hyperthyroidism.

The effect of hyperthyroidism on lipolytic and ketogenic fluxes was determined by measuring simultaneously (stable isotope methodology) glycerol, nonesterified fatty acids (NEFA), and ketone body (KB) kinetics in euthyroid and hyperthyroid subjects. In the postabsorptive state hyperthyroid patients had normal concentrations of insulin and glucagon, but increased concentrations (P less than 0.01) and turnover rates (P less than 0.01) of glycerol, NEFA, and KB. The ratio of NEFA appearance rate to glycerol appearance rate was decreased in hyperthyroid subjects (2.34 +/- 0.23 vs. 3.15 +/- 0.22; P less than 0.05), indicating that intracellular cycling between triglycerides and fatty acids was increased. The percentage of NEFA flux used for KB production, calculated from NEFA disappearance rates and KB appearance rates, was increased in hyperthyroid patients (21.20 +/- 2.75% vs. 13.37 +/- 0.63%; P less than 0.05), suggesting a diversion during hyperthyroidism of hepatic fatty acid metabolism toward ketogenesis. However, when the plasma NEFA levels of control subjects were raised by the infusion of a triglyceride emulsion to levels comparable to those observed in hyperthyroid patients their percentage of NEFA flux used for ketogenesis rose to values slightly higher (26.30%) than those of hyperthyroid subjects. In conclusion, 1) hyperthyroidism results not only in increased lipolysis, but also in enhanced triglyceride-fatty acid cycling, which could contribute to the excessive energy expenditure; and 2) the increased KB production of hyperthyroid patients results more from an increase in NEFA availability than from a direct stimulation of hepatic ketogenesis.

Adult↗
PubMed1991

Primary progressive aphasia with focal neuronal achromasia.

We describe the clinical, radiologic, neuropsychological, and neuropathologic features of a 69-year-old man with a 3-year history of progressive transcortical expressive aphasia. Neuropsychological testing showed progressive dysfunction of expressive language. Neuropathologic examination demonstrated focal cortical degeneration involving the left superior frontal gyrus, with swollen achromasic neurons and no evidence of Alzheimer's disease, Pick's disease, Creutzfeldt-Jakob disease, Lewybody disease, or other dementing disorders. This case adds to the known heterogeneity of the underlying pathology of patients with primary progressive aphasia.

Aged↗
PubMed1991

East-West and European migration in a global context.

"There is currently a great deal of concern about character and dimensions of East-West migration to Europe. By seeing this movement and potential movement in a comparative and historical setting, some understanding of the overall dynamics of labour flows in a 150 year period is gained. Key worldwide migratory movements are identified, focusing particularly on migration from Europe to the colonies and the U.S. successive periods of migration to Europe and the contemporary and projected movements to Europe from the 'East' and the 'South'. The political and social status of the migrants is also assessed."

Demography↗
PubMed1991

Storage artifact increases helper T lymphocytes and helper-to-suppressor T lymphocyte ratio to normal levels in a patient with acquired immune deficiency related complex.

An increase in both the helper/suppressor T lymphocyte ratio and the absolute number of helper T lymphocytes from subnormal to normal values was observed on overnight storage of a lymphocyte preparation from a patient with acquired immune deficiency related complex. Storage of lymphocyte preparations did not significantly alter the helper/suppressor ratio for four additional patients with acquired immune deficiency related complex but produced increases for one patient with Crohn's disease and two patients with sickle cell disease. Overnight storage of heparinized blood at room temperature did not alter the helper/suppressor ratio for one healthy volunteer and one patient with acquired immune deficiency related complex but produced increases for one patient with Crohn's disease and one patient with acute infectious mononucleosis, resulting in a change from a subnormal to a normal value in the latter patient. We suggest that physicians and laboratory directors consider storage artifacts when evaluating results of tests for absolute numbers of helper T lymphocytes or helper/suppressor T lymphocyte ratios performed on patients.

AIDS-Related Complex↗
PubMed1991

Somatostatin receptors and somatostatin content in medullary thyroid carcinomas.

Human medullary thyroid carcinomas from 19 patients were analyzed for their content in somatostatin (SRIF) receptors using receptor autoradiography with a SRIF-28 analogue and the SRIF octapeptide [Tyr3]-SMS 201-995 as iodinated radioligands. Four out of 19 cases were SRIF receptor positive with the SRIF octapeptide radioligand. These cases as well as four additional tumors were also positive with the SRIF-28 radioligand 125I-[Leu8, D-Trp22, Tyr25]-SRIF-28. High affinity binding sites pharmacologically specific for bioactive SRIF analogues, specifically located on tumor tissue, were identified. In some cases the SRIF receptors were distributed in a non-homogeneous pattern, with labelling occurring preferentially in highly differentiated tumor regions. Numerous cases were shown to have a high tumoral SRIF content measured by radioimmunoassay or immunohistochemical technique. However, there was no correlation between SRIF receptor status and tumor levels of endogenous SRIF. No correlation was seen between the clinical outcome or the survival of the patients and their tumoral SRIF receptor content. Whereas some medullary thyroid carcinomas seem to be a target for SRIF, the SRIF function in these tumors remains unclear. SRIF receptors in a group of medullary thyroid carcinomas may be useful morphological marker of these tumors and of potential interest for their in vivo localization.

Autoradiography↗
PubMed1991

Immunoassay external quality assessment schemes in France.

Several immunoassay external quality assessment schemes (EQAS) are currently operating in France. Three of them are described, special reference being made to their philosophy, aims, structure and organisation. The results obtained since the EQAS were set up, enable us to appreciate the state of the art of immunoassays and its evolution with time. The results, also, point out the need to use control samples of high quality.

Biomarkers, Tumor↗
PubMed1991

Validity and generalizability of global ratings in an objective structured clinical examination.

The performance of foreign medical graduates on multistation standardized patient-based tests and used to determine the validity and generalizability of global ratings of their clinical competence made by expert examiners. Data were derived from the entrance examinations of the 1989 and 1990 applicants to the Ontario Pre-Internship Program and the exit examination of 24 participants from the 1989 cohort. For each candidate, the examiners completed a detailed checklist and two five-point global ratings dealing with the candidate's approach to the patients' problem and attitude toward the patient. Generalizability coefficients for both ratings were satisfactory and stable across cohorts. Construct validity of the global ratings was demonstrated by comparing entry and exit ratings and by evidence of significant and positive correlations between the global ratings and total test scores. Tentative evidence of criterion validity of the global ratings was demonstrated. These findings suggest that global ratings by expert examiners can be used as an effective form of assessment in multistation standardized patient examinations.

Attitude of Health Personnel↗
PubMed1991

[Cefaclor versus penicillin V in staphylococcal infections in children].

Although rheumatic fever virtually no longer occurs in France, pharyngitis due to group A beta-hemolytic streptococci (ABHS) remains a common pediatric problem. American studies have underscored the high rate of bacteriologic treatment failures and recurrences of ABHS pharyngitis. Furthermore, several comparative studies have demonstrated that cephalosporins provide better results on these two parameters. This prospective randomized study compared the effectiveness of penicillin V (50,000 to 100,000 IU/kg/day in three divided doses) and Cefaclor (20 to 40 mg/kg/day in three divided doses), each given for ten consecutive days. From September 1989 through October 1990, 117 children (mean age 5.7 years) were entered into the study. All study subjects were seen as outpatients and found to have ABHS pharyngitis on the basis of a rapid screening test and confirmatory bacteriologic studies. Cefaclor was given to 56 patients and penicillin V to 61. Reevaluation with a repeat bacteriologic study was performed in all patients at the end of the treatment period, or earlier in the event of new clinical manifestations, and towards D40. Among patients given penicillin V, bacteriologic failure rate at completion of therapy was 19.6%, clinical failure rate on D10 was 8%, and recurrence rate on D40 was 16.5%. Cefaclor exhibited greater bacteriologic and clinical effectiveness, with 3.4% bacteriologic failures on D10 (p less than 0.01), 1.7% clinical failures on D10, 8.9% clinical recurrences between D10 and D40, and an overall 10.6% rate of failure or recurrence (p = 0.05).

Adolescent↗
PubMed1991

[An open randomized trial, Pediazole versus cefaclor in the treatment of acute otitis media in children].

The combination of erythromycin ethylsuccinate and acetyl sulfafuroxazole (Pediazole = ES) is effective against Hemophilus influenzae, including beta-lactamase-producing strains, and against Streptococcus pneumoniae, including macrolide-resistant strains. In this study, mean daily dosage was 40-50 mg/kg for cefaclor and 50 mg/kg ES + 150 mg/kg sulfamide for Pediazole. Both products were given in three divided doses per day for ten days. Tolerance was evaluable in 106 children and effectiveness in 103 children including 52 in the ES group and 51 in the cefaclor group. Mean age was 23.5 months and both groups were comparable as concerns age, weight, previous ENT disease, and severity of the otitis media. Tolerance was satisfactory in both groups. Clinical results were as follows: failures before or at completion of the course, 5/52 in the ES group versus 13/51 in the cefaclor for the treatment of children with acute otitis media.

Acute Disease↗
PubMed1990

PCR amplification of CGRP II mRNA. Variable expression in tumoral and non-tumoral human thyroid.

Two genes code for calcitonin gene-related peptides (CGRPs). One expresses by tissue-specific alternate splicing calcitonin and CGRP I mRNAs, the other CGRP II mRNA. Calcitonin is the marker of sporadic or hereditary human medullary thyroid carcinoma (MTC). CGRP II expression is not well established in normal or tumoral thyroid. After amplification by polymerase chain reaction, CGRP I and II mRNAs were detected in six cases of MTC associated with other endocrine neoplasia (MEN IIa) and in two cases of isolated MTC. CGRP I was detected in all non-C cell tumoral thyroids (6 samples), CGRP II was barely detectable in three out of six cases. CGRP II could be a specific tumoral marker of MTC.

Base Sequence↗
PubMed1990

Persistent B19 parvovirus infection in patients infected with human immunodeficiency virus type 1 (HIV-1): a treatable cause of anemia in AIDS.

OBJECTIVE: To determine the role of B19 parvovirus in red cell aplasia of patients infected with human immunodeficiency virus type 1 (HIV-1). DESIGN: Uncontrolled clinical trial, with assay of serum, peripheral blood cells, and bone marrow for virus using DNA hybridization and immunocytochemistry techniques; these assays were then correlated with clinical findings, results of immunoassays for antivirus antibodies, and with immunoglobulin (Ig) therapy. SETTING: Government medical referral center, and university and private hospitals. PATIENTS: Seven patients with pure red cell aplasia and serologic evidence of infection with HIV-1. MEASUREMENTS AND MAIN RESULTS: All patients had giant pronormoblasts in the bone marrow (present in transient aplastic crisis caused by acute B19 parvovirus infection). High concentrations of B19 parvovirus were demonstrated in sera, in several cases in samples separated by weeks or months. Viral DNA and capsid protein were present in the bone marrow of three patients studied, and active viral replication was detected by southern analysis. There was no antivirus IgG in capture immunoassay and no or very low levels of antivirus IgM. The patients did not have symptoms of fifth disease, the illness caused by this virus in immunologically normal persons. Six patients were treated with a regimen of intravenous commercial immunoglobulin. In all cases, this therapy resulted in rapid reduction in serum virus concentrations and full recovery of erythropoiesis. Relapses in two cases were predicted by DNA hybridization studies, and these cases were successfully retreated. CONCLUSIONS: The B19 parvovirus is a remediable cause of severe chronic anemia in HIV-infected patients. Recognition of and therapy for parvovirus in this population will avoid erythrocyte transfusion and should prevent transmission of the virus to other persons, including immunosuppressed persons and women of child-bearing age.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Immunocytochemical characterization of lung tumors in fine-needle aspiration. The use of cytokeratin monoclonal antibodies for the differential diagnosis of squamous cell carcinoma and adenocarcinoma.

In the current study, immunocytochemical typing of intermediate filaments was used for a differential diagnosis of human lung tumors from transthoracic fine-needle aspiration biopsies (TFNAB). The authors have compared the cytologic diagnosis of 53 lung cancer cases with the immunofluorescence patterns obtained using a panel of monoclonal antibodies, five of which (KG 8.13, KM 4.62, Ks B.17, KS 8.12, KK 8.60) react with specific cytokeratin polypeptides and one with vimentin (VIM 13.2). Only in six of 23 samples cytologically diagnosed as squamous cell carcinoma did the immunocytochemical typing of cytokeratins (ICTC) confirm the cytologic diagnosis. In seven cases some of the tumor cells stained positively with antibody Ks B.17 specific for simple epithelial keratin (No: 18), suggesting the presence of some cells of glandular origin. In ten additional cases the ICTC was in conflict with the cytologic diagnosis of squamous cell carcinoma (i.e., antibodies Ks 8.12 and KK 8.60 were negative, and antibody Ks B.17, positive) supporting a diagnosis of adenocarcinoma. In 14 of 18 cases cytologically diagnosed as adenocarcinoma, the ICTC confirmed the diagnosis whereas in four cases additional presence of some squamous cells was noticed. The ICTC labeling of cases cytologically diagnosed as undifferentiated and large cell carcinomas was similar to that of the group of adenocarcinomas. Thus, the application of cytokeratin typing for TFNAB samples seems to provide a vital complementation to routine cytologic study, especially for cases cytologically diagnosed as squamous carcinoma.

Adenocarcinoma↗
PubMed1990

Identification and characterization of an adenovirus 2 major late promoter CAP sequence DNA-binding protein.

DNase I footprint analysis of the core adenovirus 2 (Ad2) major late promoter (MLP) has revealed distinct patterns of protection corresponding to the assembly of transcription components during transcriptional initiation (VanDyke, M. W., Sawadogo, M., and Roeder, R. G. (1989) Mol. Cell Biol. 7, 3371-3379). By using partially purified transcription factors, DNase I protection over the TATA box element and the CAP sequence was attributed to the binding of a single factor, TFIID. We have determined, however, that protection of the CAP region results from the binding of a novel factor, designated CAP-site binding factor (CBF), which is chromatographically and functionally distinct from TFIID. DNase I footprint analysis and gel electrophoresis mobility shift competition assays confirm that distinct polypeptides bind to the Ad2 MLP upstream promoter sequence, TATA box, and CAP sequences. When the CAP sequence is mutated, transcriptional activity of the Ad2 MLP is reduced both in vitro and in vivo. The decrease in transcriptional activity correlates with decreased CBF binding activity. Nuclear extracts depleted of CBF also exhibit reduced Ad2 MLP transcriptional activity. The addition of DNA affinity purified CBF, free of TFIID or major late transcription factor, restores the activity to control levels.

Adenoviruses, Human↗