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Biomedical subjects

H Atlan

Publications and source records attributed to H Atlan.

At least 73 records · Page 4Linked to original sources

Carcinoma of the bronchus with atypical presentation: report of a case.

A 64-year-old man presented with dysphagia due to obstruction of lower third of the esophagus. Esophagoscopy showed narrowing of the esophagus with normal mucosa. Chest X rays were normal, but on lung scan there was no perfusion of the left lung. That patient died of aspiration and on post mortem a carcinoma of the bronchus with abscess formation and perforation into the esophagus was found.

Bronchial Neoplasms

Radionuclide assessment of aortocoronary bypass surgery.

Rest and exercise thallium 201 myocardial scintigraphy and multiple gated radionuclide angiography were correlated with the results of clinical status, exercise electrocardiography, coronary arteriography, and contrast left ventriculography in a series of 12 prospectively studied consecutive patients before and after aortocoronary bypass operation. Patients were divided into two groups based on a comparison between preoperative and postoperative 201T1 scintigrams. Group 1 (6 patients) demonstrated improved or normal postoperative perfusion scintigrams and excellent correlation between the site of a patent graft and the improvement in myocardial perfusion on the postoperative exercise scintigrams. Regional wall motion remained normal in 3 patients and improved in 3. In Group 2 (6 patients) the postoperative 201T1 scintigrams were unchanged or worse. Each patient demonstrated graft occlusion, graft stenosis, distal disease, or a perioperative myocardial infarction. No improvement in regional wall motion occurred in 4 of these 6 patients. Neither the symptomatic response to aortocoronary bypass operation nor the response to exercise testing successfully predicted graft patency.

Adult

[Study of muscle hemodynamics during exercise: Physiological and pathological variations in Xe 133 elimination: A new method of interpretation (author's transl)].

Muscle blood flow measurements are of physiological (and pathological) significance only during effort. For this reason, the authors used Xe 133, which has been known since 1964, to measure regional muscle blood flow after its injection into the muscle, to quantify results during effort (pedalling). Effort is controlled by two measurable parameters: the weight lifted by the pedal and the frequency of movements. Curves showing the reduction in intramuscular Xe 133 levels cannot be mathematically formulated. It is easy, however, to measure their areas and thus define a mean elimination time (Tm) between times T1 and T2, beginning and end of effort, corresponding to activities A1 and A2 such that: formula: (see text). Normal Tm value, measured in 58 normal subjects with variable frequencies and weights lifted is: Tm = 1.70 +/- 0.38 min. The values in 70 patients with arteritis were significantly longer and can be greater than 3.5 min. This objective test could be of value in quintifying the effects of so-called vasodilators, both in patients with arteritis and venous insufficiency.

Humans

Interaction between membrane properties and proteins synthesis in reticulocytes - a two step inhibition of protein synthesis by valinomycin.

In this work we consider the differential effect of Valinomycin used at different concentrations both on the protein synthesis of reticulocytes and on 42K exchange. We demonstrate that there is a two step action of this antibiotic. At 10(-6)M and below the drug has no effect on the 42K exchange, but it stops, however reversibly, protein synthesis. At 10(-5)M the drug has a very sharp action on the 42K exchange and stops protein synthesis in an irreversible way. Ribosomal population checked by two ways, sucrose gradient and direct counting on E.M. sections shows that at low concentrations of Valinomycin (10(-8)M to 10(-6)M) there is no breakdown of the polysomes which can be detected by either one of these methods. On the contrary, after short incubation with 10(-5)M of Valinomycin the breakdown of ribosomes is very clear, as evidenced by sucrose gradient analysis. By direct ribosomes clusters counting on E.M. sections this breakdown is seen only after long incubation.

Animals

[Variability of cultures and genetic variability].

Cultural selection is defined as a modification in gene frequency distributions within a population under the effects of socio-cultural factors. The conditions are examined which determine the efficiency of such a selection mechanism as a driving force for the evolution of the genetic pool of a social group in a state of relative isolation. The possible effect of the cultural variation on the genetic variation of the human species is discussed.

Culture