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Biomedical subjects

R Gay

Publications and source records attributed to R Gay.

At least 19 recordsLinked to original sources
PubMed1979

[Severe drug complications: current prevalence amongst patients admitted to adult intensive care units (author's transl)].

A retrospective study involving nine teaching hospital mixed intensive units provided information concerning severe drug complications amongst patients admitted to these departments over the past ten years. Amongst a total of 63717 patients admitted, there were 1132 drug complications (1.8%) without any predominance in terms of sex. Mortality was high (252 patients, i.e. 22.2%), being all the greater in older patients. Details concerning the various drug complications are given, the most common being anaphylactic shock and haemorrhage due to anticoagulants. These statistics are compared withthose already published by hospital departments of internal medicine.

Age Factors↗
PubMed1979

Immunohistochemical demonstration of basement membrane collagen in normal human skin and in psoriasis.

Antibodies prepared against the collagen C-chain derived from human placenta specifically strain the epidermal basement membrane of normal human skin as well as the basement membrane surrounding the skin appendages and capillaries. Using the antibodies, it was observed that all basement membranes in untreated psoriatic plaques appear fragmented and separted into several layers. The results suggest that psoriatic lesions are associated with a general loss of basement membrane integrity which may play a crucial role in the pathogenesis of the disease.

Antibody Specificity↗
PubMed1979

[The Davenport diagram and the international system of units].

The implantation of the international system of units in medical science leads to revising the Davenport diagram. This diagram has been widely used for 20 years as a system displaying the variations in acid-base equilibrium. In order to conserve its familiar aspect the coordinates are: a pH abscissa complete with a scale of H+ ion concentrations (nmol.l-1) and an ordinate using real plasma HCO-3 concentrations. The isobars of PCO2 are reconstructed for whole and semi-whole kilopascal values (kPa). The real plasma buffer lines are reconstructed for 3, 6 and 9 n.mmol.-1 of monomeric hemoglobin which are the nearest whole values of 5, 10 and 15 g of Hb/100 ml. The diagram is calculated for 37 degrees C and the constants used for pK' and aCO2 are the most recently suggested values.

Acid-Base Equilibrium↗
PubMed1978

Changes in the surface of the mouse blastocyst at implantation.

Implantation is a critical event, and perhaps the earliest one, in the maternal recognition of pregnancy. Information transfer from conceptus to mother might occur during, and subsequent to, implantation at the level of cell surface interaction. Therefore, attempts have been made both to identify the phases of implantation during which changes in the blastocyst surface occur and to characterized such changes. In vitro, blastocysts have been found to go through a series of discrete steps which are analogous to implantation in utero, and these steps can be retarded or prevented by the use of either suboptimal culture media or an inappropriate substratum. Morphological surface changes are not apparent when the blastocyst becomes adherent to the substratum; however, marked differences in blastocyst surface structure are revealed by scanning electron microscopy at the onset of trophoblast outgrowth. Studies at the molecular level implicate collagen as having a role in blastocyst adhesiveness, but other cell surface components are also likely to be involved.

Animals↗
PubMed1978

[Demonstration, kinetic study and solubilization of particular adenylate cyclase from Nocardia restricta].

An adenylate cyclase (EC r.6.1.1.) was found in cell-free extracts of several Nocardia species. The enzyme from Nocardia restricta has been specially studied. It is a membrane enzyme which exhibits a strong specific activity, one hundred times greater than that of mammals. It has an optimal pH of 8.5 in Tris buffer and an absolute requirement for divalent ions, Mg++ or Mn++ (Mn++ ions are the most efficient). The kinetic properties of this adenylate cyclase are similar to those that could be expected of an allosteric enzyme having, as a substrate, the ATP-Mg++ complex and, as an activator, free Mn++ ions. Ca++ ions are activators: they set up the maximum velocity without modification of the KM. GTP is a competitive inhibitor (KI = 5.10(-5) M). Fluoride ions have no detectable effect on activity. Non-ionic detergents, Lubrol WX and Triton X 100, are inhibitors of the enzyme which has been partially solubilized by repeated freezing and thawing, following by brief ultra-sonic treatment. Catalytic sites are not modified after the solubilization, but cooperative effects between moles of substrate ATP-Mn++ are diminished: the KM becomes smaller and the sigmoidal shape of the curve v = f (ATP-Mn++) is attenuated.

Adenylyl Cyclases↗
PubMed1978

[Acute renal insufficiency caused by phenyl-indane-dione. Apropos of 1 case].

One case of Phenindione (PID) adverse reaction is reported. The patient showed a typical picture of immunological reaction to the drug. In spite of severe bacteremia, she recovered. Only 33 cases of PID intolerance are reported in the literature. In all these patients, renal failure occurred. Superinfection is the most frequent cause of death. PID adverse reaction should be evoqued in the presence of signs such a fever, asthenia, anorexia and cutaneous reaction. The PID should be stopped immediatly but renal failure yet develops. During a PID treatment, frequent evaluation of blood azotemia, creatinine and proteinuria should be performed.

Acute Kidney Injury↗
PubMed1977

Transitions in collagen types during matrix-induced cartilage, bone, and bone marrow formation.

The localization of types I, II, and III collagens during bone matrix-induced sequential differentiation of cartilage, bone, and bone marrow was studied by specific immunofluorescence. Subcutaneous transplantation of coarse powders of demineralized rat bone matrix into allogeneic recipients resulted in new bone formation. After a transient appearance of polymorphonuclear leukocytes in the implant, fibroblasts appeared in close continguity to the matrix on day 3. Type III collagen was then localized as a fine network around the invading fibroblasts. On days 4--6 smaller amounts of type I were also detected around these proliferating cells. With the onset of chondrogenesis, type II collagen was detected in the cartilage matrix on day 6 and persisted until the early stages of bone formation. Vascular invasion of the implant was accompanied by osteogenesis on day 10. Type I collagen was demonstrated in the newly deposited bone matrix coating the surfaces of cartilage spicules and particles of implanted bone powder. On day 17 and thereafter, type III collagen was localized as a fibrous array around nests of hematopoietic cells.

Animals↗
PubMed1977

[Study of the NADH and NADPH-ferredoxin oxidoreductase activities in Clostridium acetobutylicum].

The NADH and NADPH-ferredoxin oxidoreductase have been studied in Clostridium acetobutylicum. Acetyl-CoA is an obligatory activator of NADH-ferredoxin reductase activity and NADH a competitive inhibitor of ferredoxin-NAD+ reductase activity. These regulations are the same when C. acetoburylicum moves from 'butylic-type metabolism' to 'butyric-type metabolism'; this demonstrates that NADH-ferredoxin oxidoreductase cna, through its reversible action, meet the very different cell needs imposed by these two types of culture. The physiological function of the clostridial NADPH-ferredoxin oxidoreductase was anabolic as it has been with other clostridia.

Acetyl Coenzyme A↗