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Biomedical subjects

J F Stoltz

Publications and source records attributed to J F Stoltz.

At least 181 records · Page 10Linked to original sources
PubMed1983

[Determination of the membrane fluidity of human blood platelets by measuring the anisotrophy of the fluorescence emission].

Incorporation in vitro of 1,6-diphenyl-1,3,5 hexatriene (DPH) in washed human blood platelets was studied to determine a reference value of fluorescence emission anisotropy of DPH and thus the "microfluidity " of platelet lipid zones. Parameters evaluated were the effect of time of incorporation of the marker, of temperature (25 and 37 degrees C), and of cellular concentration, as well as the effect of platelet aging, enabling determination of valid experimental conditions for studying interaction with drug molecules.

Blood Platelets↗
PubMed1982

Hemorheological and biochemical parameters in the "fatty" rat.

The essential part played by rheological factors in genesis of thrombosis and atherosclerosis has often been mentioned. Thus the authors have carried out a study of rheological and biochemical parameters on a genetic animal model with modifications in plasma lipids (homozygous obese "Fatty" rat) compared to the non obese heterozygous animal. The results obtained for the evolution of biochemical parameters (blood glucose, cholesterol, triglycerides) over a 16 months period confirm those published earlier. Further, a significant increase in fibrinogen level was observed in homozygous animals, and correlated with plasma viscosity. There results are also connected with changes in apparent blood viscosity which is considerably increased in homozygous rats, particularly at low shear rates (gamma less than 20 s-1). These results show the value of this animal model and the authors suggest the application of such a genetic animal model and of its heterozygous control population to both theoretical rheological and pharmacological studies on atherogenesis and hyperlipoproteinaemia.

Animals↗
PubMed1982

New device for determination of cell electrophoretic mobility using doppler velocimetry.

Electrical phenomena of cell membranes may be examined by means of cell electrophoresis. Direct microscopic techniques are tedious, inaccurate and rarely reproducible. Therefore, the authors have developed a new device using Doppler velocimetry. After describing the apparatus, they propose two methods for testing treatment against electroosmosis and present the first biological applications on mixed populations of red cells.

Cell Membrane↗
PubMed1982

[Changes of beta-thromboglobulin levels in diabetic patients controlled with the artificial pancreas].

beta-Thromboglobulin (beta-TG), which is a specific platelet protein, is considered to be a fair indication of in vivo platelet activation. Our investigation was aimed at testing the influence of the glucose balance on platelet behaviour by measuring beta-TG levels in insulin-dependent diabetic patients subjected to blood feed-back control via an artificial pancreas over a 24 or 48 hour period. In 19 patients who underwent feed-back control over a 24 hour period, no significant change in beta-TG level was observed on average, compared with the measurements carried out before blood glucose control. In contrast, in the 11 diabetic patients treated over a 48 hour period, this plasma level decreases slightly but significantly compared with the levels observed before glycemia regulation (55.6 +/- 26.6 ng/ml vs. 74.2 +/- 24.9 ng/ml). We were unable to find any correlation in these patients between the beta-TG levels measured at each of the three sampling periods and the blood glucose level-measured simultaneously or continuously-or the glycosylated hemoglobin level measured at the beginning of the study. These results suggest that, in spite of the lag phase, blood glucose control has a beneficial influence on the platelet hyperactivity and therefore a poor glycemia regulation could be largely responsible of this disorder. However, in view of the persistence of abnormally high plasma beta-TG level after 48 hours, we are led to believe that strict blood glucose control has not been sufficiently prolonged.

Adolescent↗
PubMed1982

[Influence of metabolic control on blood viscosity and platelet activity in insulin requiring diabetics].

Blood and plasma viscosities were determined using respectively a Couette type micro-viscometer (LS 30) and an automatic capillary viscometer (FICA). Plasma beta-thromboglobulin (beta-TG) levels were determined by radioimmunoassay. These parameters were measured in a group of 11 poorly controlled insulin requiring diabetics before and after blood glucose normalization using an artificial pancreas (Biostator GCIIS). Before connection to the artificial pancreas, blood and plasma viscosity and beta-TG levels were significantly higher in diabetics than in controls. The strict metabolic control obtained by the artificial pancreas resulted in a normalization of the hemorheological parameters and in a significant reduction of plasma beta-TG levels after 48 h. These results suggest that the metabolic control of diabetes influences the rheological behavior of blood and the metabolism of platelets.

Adolescent↗
PubMed1982

[Climatologic parameters and risk of acute vascular, neurologic and cardiac incidents].

In order to discover a possible correlation between climatic parameters and the occurrence of acute neurological vascular accidents (thrombosis, hemorrhages) and of cardiac accidents (myocardial infarction), the data of a meteorological card-index including climatological parameters [atmospheric pressure in millibars, temperature of the air under shelter in degrees Celsius, relative humidity, speed and direction of the winds, hydrometeors and electrometeors) as well as parameters of solar and ionospheric activity (daily flare index (DFI), index of the geomagnetic activity (AA), daily planetary index (AP), phases of the moon] were compared. The study concerned a period of 731 days and the parameters, subdivided into classes and gradients, were compared with the admission to hospital of 535 patients with myocardial infarction and of 378 patients with stroke. The statistical study consisted in searching for correlations between the parameters considered two by two and in applying the method of the factorial analysis of correspondence for a more extensive analysis. The frequency of the vascular accidents increased when the temperature of the air was less than 12 degrees, when there was hoar-frost with fog, rain or snow and when the DFI was less than 530. The factorial analysis of correspondence enabled to consider 3 fields in which correlations were suggestive for 3 distinct affections: myocardial infarction, cerebral hemorrhages and cerebral thrombo-embolisms.

Cerebrovascular Disorders↗
PubMed1981

[Blood viscosity. Measurement and applications (hyper--and hypoviscosity syndromes) (author's transl)].

Blood has particular rheological properties which partly condition its flow, especially in capillary vessels, and its ability to deliver oxygen. It is not subject to gravitation, pseudoplastic, thixotropic and visco-elastic. Blood viscosity depends upon macroscopic factors, such as erythrocyte aggregation and deformability. Hyperviscosity is observed in cases of increased haematocrit (polycythaemia and relative polycythaemia), increased serum proteins and changes in protein balance (e.g. rise in fibrinogen and immunoglobulins, fall in albumin) as seen in inflammation and dysglobulinaemia, drop in temperature (hypothermia), increased erythrocyte aggregation (shock, fat embolism) or imparied deformability due to various acquired or inherited disorders of red cell membrane or cytoplasma (e.g. sickle cell anaemia, renal failure, hyperlipoproteinaemias, thrombosis, diabetes). The various factors may be combined, as in diabetes. Conversely, hypoviscosity may result from decreased haematocrite, fall in blood proteins and fibrinogen, or hyperthermia. Hyperviscosity can be corrected by acting on its various constituents. Treatments include haemodilution, plasmapheresis, anti-aggregants and drugs improving red cell deformability.

Blood Proteins↗
PubMed1981

Plasma viscosity and biochemical parameters in the "fatty" rat.

The essential part played by rheological factors in the genesis of thrombosis and atherosclerosis has often been mentioned. Thus, we undertook an investigation on plasmatic rheological factors in an animal model with modifications in plasma lipids (homozygotic and heterozygotic "fatty" rats) compared to normal animals (Sprague-Dawley rats). Test parameters were: cholesterol, triglycerides, lipidograms, glucose, total proteins, fibrinogen, plasmatic viscosity. Experiments gave the following results in homozygotic animals as compared to heterozygotic rats and controls: hyperlipidemia with massive increase in triglycerides, hyperfibrinogenemia, increase in total proteins and glucose, modifications in lipidogram in the form of more lipoproteins migrating in the beta-position and fewer proteins migrating in the alpha-position. Such changes were accompanied by an increase in whole blood and plasma viscosity. After considering the various correlations between these parameters, the authors suggest the application of such an animal model to atherogenesis.

Animals↗
PubMed1981

Deformation and orientation of red blood cells in a simple shear flow. Theoretical study and approach at small angle light scattering.

On the basis of a simple theoretical model representing the rheological behaviour of the erythrocyte membrane, the authors have proceeded with a theoretical and experimental investigation on the light-scattering diagrams at small angles of normal red blood cells subjected to Couette flow. The results show that the light-scattering diagrams take into account not only cell deformation, but also cell orientation. The prospects for applying this method to the analytical separation of cells with different deformabilities are considered.

Biophysical Phenomena↗