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Biomedical subjects

D Levy

Publications and source records attributed to D Levy.

At least 433 records · Page 24Linked to original sources
PubMed1977

Bovine leukemia virus specific antibodies among French cattle. I. Comparison of complement fixation and hematological tests.

Complement fixation (CF) and hematological studies were performed on 517 cows living in normal conditions in different geographical areas of France. The animals belonged to three different categories: (1) multiple or single case herds, in which lymphosarcomas had been detected in the past five years. (2) Leukemia free herds of high risk regions. (3) Leukemia free and apparently unexposed herds. Positive animals were found with both methods in the first two categories but not in the third. Persistent lymphocytosis and CF antibodies were more frequent in leukemia than in exposed but leukemia free herds. Approximately 2 times more animals were found positive by serologic than by hematologic tests. The mean geometrical titer of CF antibodies was higher in lymphocytotic than in normal animals and highest in lymphosarcomatous cows. Persistent lymphocytosis was first detected in 3-years-old animals whereas 22% of younger cows were positive in the CF test.

Animals↗
PubMed1977

[New methods in the treatment of weather sensitivity].

Changing weather fronts produce severe changes of daily rhythms. Electrical impulses arrive 1-2 days before the weather and create either atmospherics or "positive ions". They are responsible for the epidemic appearance of migraine and of thrombo-embolism. The impact of atmospheric electricity has been assessed in 1000 patients by daily urinalysis of serotonin, 5-HIAA, adrenaline, noradrenaline, histamine, thyroxine, 17-KS, 17-OH, Na, K, creatinine and diureses. The changes found in these 12 parameters allowed a classification of heat reactions into three clinical entities: 1. serotonin hyperproduction causing a typical irritation syndrome: 2. adrenal deficiency producing a typical exhaustion syndrome; 3. hyperthyroidism "Forme fruste" with subclinical "apathetic" thyroid symptoms. These sufferings, typical for Föhn, Tramontana, Sirocco, Sharkiye, Chamssin, Sharav and Santa Ana Winds, are mainly due to positive ionisation of the air. They can be prevented by negative ionising apparatuses or specific drug treatment.

Electric Stimulation Therapy↗
PubMed1977

Photocatalyzed labeling of adipocyte plasma membranes with an aryl azide derivative of glucose.

The photoreactive glucose derivative, N-(4-azido-2-nitrophenyl)-2-amino-2-deoxy-D-glucose, has been synthesized and used as a site-directed probe to label adipocyte plasma membranes. In the absence of photoactivation, the glucose derivative was shown to inhibit D-glucose and 3-O-methyl-glucose uptake in the isolated adipocyte system. Glucose was also shown to partially inhibit the uptake of the photoreactive probe. Photolysis of this reagent with light of wavelength greater than 300 nm in the presence of intact adipose cells resulted in the covalent incorporation of radioactivity into the plasma membrane fraction. Analysis of this material by sodium dodecyl sulfate-polyacrylamide gel electrophoresis indicated that four membrane components were significantly labeled and that two of these components corresponded in electrophoretic mobility to the major glycoproteins with apparent molecular weights of 100,000 and 81,000. Photolysis of the glucose analog in the presence of the particulate pellet derived from homogenized adipocytes resulted in the incorporation of the radioactive label into most of the membrane proteins. Although the cells appear to be permeable to the photoreactive probe, only a few membrane components are labeled when the cells are intact, suggesting that the probe has a high affinity for these membrane components which may be functionally involved in the glucose transport system.

Adipose Tissue↗
PubMed1977

Proteins of bovine leukemia virus. I. Characterization and reactions with natural antibodies.

The bovine leukemia virus (BLV) was purified from a chronically infected fetal lamb kidney cell line. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis of this virus revealed the presence of eight distinguishable viral components with molecular weights ranging from 80,000 to 11,000. The major component is a non-glycosylated protein having a molecular weight of 24,000 (p24). At least three heavier polypeptides were found, one of them representing a glycoprotein (gp 60). In addition, four minor polypeptides with respective molecular weights of 19,000, 16,000, 13,000, and 11,000 were identified. In a complement fixation assay using naturally occurring antibodies of a leukemic cow, four polypeptides, which included gp 60, p35, p24, and p16, were found to be reactive.

Antibodies, Viral↗
PubMed1977

Relationship between acute respiratory illness and air pollution levels in an industrial city.

A retrospective study relating air pollution levels to hospital admissions for acute exacerbations among adults with chronic respiratory illness and children with acute respiratory disease was carried out in a highly industralized Canadian city. A total of 1,780 patient records were collated, and daily, weekly, and monthly hospital admission rates were related to a standard air pollution index that took into account floating particles and sulfur dioxide. A correlation coefficient of 0.77 (P less than 0.01) between number of admissions and level of air pollution was found for the city as a whole, and the strength of the association varied inversely with the distance of the hospital from the industrial area.

Acute Disease↗
PubMed1976

Fluorine nuclear magnetic resonance studies of trifluoroacetylinsulin derivatives. Effects of salts and denaturants.

19F nuclear magnetic resonance spectroscopy has been used to study the effects of salts and denaturants on the structure and aggregation properties of several trifluoroacetyl derivatives of insulin. This technique has been shown to be a powerful tool in the study of specific sites on the protein molecule. Circular dichroic and sedimentation velocity studies were also carried out to aid in the interpretation of the magnetic resonance data. At pH 6.8 Zn2+ had no effect on the 19F magnetic resonance spectrum, however, citrate and acetate ions significantly sharpened the signal from the trifluoroacetyl probe at the N-terminal end (glycine A-1) of the insulin A chain. No alterations were observed in the S20,W value of circular dichroic spectra, suggesting that the probe had gained a considerable degree of motional freedom without changes in aggregation or conformational properties. In the absence of perturbants the trifluoroacetyl group on glycine A-1 showed considerably more motional freedom than on phenylalanine B-1. Guanidine hydrochloride and sodium dodecyl sulfate were used to study the unfolding of several trifluoroacetylinsulin derivatives. The results suggested differential alterations in the environments of the probes located at glycine A-1, phenylalanine B-1, and lysine B-29 in the insulin molecule as the concentration of perturbant was increased.

Binding Sites↗
PubMed1976

Clinical, epidemiologic, and pulmonary function studies in alpha,-antitrypsin-deficient subjects of Pi Z type.

The results of pulmonary function testing and systematic medical history and epidemiologic data collection are reported for 20 persons with alpha 1-antitrypsin deficiency of Pi Z phenotype. The most common symptom, reported in 19 subjects (95 per cent), was dyspnea on exertion; 16 subjects (80 per cent) gave a history of wheezing, and 8 (40 percent) reported chronic cough and sputum production. The 8 women who had been pregnant reported a miscarriage rate of 29 per cent for all pregnancies. Respiratory symptoms and disease were commonly reported in the children of study subjects. Pulmonary function testing revealed abnormalities for 18 of 20 subjects, all of those 26 or more years of age. The test that was most frequently abnormal was the 1-sec forced expiratory volume expressed as a per cent of the forced vital capacity. All pulmonary function studies demonstrated a trend toward increased impairment with increased age, which was evident by the fourth decade. Within this group of persons having severe alpha1-antitrypsin deficiency, there was no correlation between serum concentrations of antitrypsin and subjective or objective indices of pulmonary disease. A group of 7 subjects who were incidentally found to have Pi Z alpha1-antitrypsin deficiency exhibited symptoms and pulmonary function abnormalities comparable to those of 13 subjects who were originally referred for known or suspected pulmonary disease. These data suggest that if interventions such as smoking cessation and occupational counseling are to be effective, they should be initiated before the fourth decade of life.

Adult↗
PubMed1976

[Role of peridural anesthesia in thoracic surgery].

Periduralaneaesthesia by the cervical route (C6-C7 or C7-D1) or by the upper lumbar route with an ascending catheter, permit thoracic surgery in all its applications. The reduction in operative bleeding is an appreciable advantage of the method, and automatic nervous stability is remarkable. On the other hand, keeping the patient in the waking state is a definite disadvantage, especially in removal of one lung. As far as the anaesthetist is concerned he will be faced with difficulties of ventilation and bronchial aspiration. On the other hand, combined with slight general anaesthesia and tracheal intubation, peridural anaesthesia is definitely of interest. Furthermore, during the post-operative period, it is precious permitting a cough without pain and, in this respect, the comparison with anaesthesia of the inter-costal nerves, is worth discussins, each technique having special advantages.

Anesthesia, Epidural↗