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Biomedical subjects

A Paraf

Publications and source records attributed to A Paraf.

At least 91 records · Page 5Linked to original sources
PubMed1976

Plasma membrane studies on drug-sensitive and -resistant cell lines. II. Ouabain sensitivity of (Na+ +K+)-stimulated Mg2+-ATPase.

Mutant cell lines have been selected from the murine plasmocytoma MOPC 173 for their resistance to ouabain, dibutyryl cyclic AMP, theophyllin and concanavalin A. We have compared three wild-type cell lines with their seven resistant counterparts. All resistant mutants exhibited a (Na+ + K+)-stimulated Mg2+-ATPase resistance to ouabain inhibition when measured in microsomes. The homogeneity of ouabain binding sites has been found in most of the cell lines; however, two different populations of sites have been detected in one wild-type and in one resistant cell lines. These results led us to hypothetise the (Na+ + K+)-ATPase-ouabain interaction being modulated by a non-specific membrane structure.

Adenosine Triphosphatases↗
PubMed1976

[Senile common bile duct. Radiological study].

From this study carried out under sufficiently strict conditions to analyze normal common bile ducts of the third to the tenth decade, with radio-geometric measurement redusurement reducing errors as far as possible, it appears that: a) there is no difference in the frequency and the density of opacification of the bile duct in young or elderly subjects, b) that the radiological diameter of the normal bile duct becomes enlarged with time, according to the formula: (see article) which may be considered in routine clinical practice as a true increase in diameter of about 1 mm per decade. The limits of true diameter of the bile duct, in our experience, were +/- 3 mm at 30 years to +/- 7 mm after 80 years.

Adult↗
PubMed1976

[The role of distinct membrane components of the enzyme in the ouabain sensitivity of Na+/K+ ATPase].

Purified plasma membranes from a cell line derived from the murine plasmocytoma MOPC 173 exhibited a 50% inhibition of the Na+K+ ATPase by 120 muM ouabain. EDTA treatment of such membranes induced a drop in the ouabain concentration needed for 50% inhibition to 0.4 muM. Supernatants obtained after EDTA treatment were able to complement with Ca(++) + Mg++ the washed EDTA treated membranes which recover their original resistance.

Adenosine Triphosphatases↗
PubMed1976

Differences in cell surface proteins of drug resistant and sensitive cell lines.

Lactoperoxidase catalyzed iodination of cell surface proteins has been used to compare theophylline and ouabain resistant variants with the drug sensitive parental cell lines. In cells showing contact inhibition a high molecular weight protein was observed to be preferentially labelled. In contrast this was not observed for non contact inhibited cells. These results support a previously suggested correlation between growth regulation and the exposure of this cell surface protein.

Animals↗
PubMed1976

[Transient acanthocytosis in a patient with liver cirrhosis. Study of red cell and plasma lipids (author's transl)].

The authors report a case of major acanthocytosis which regressed spontaneously in a cirrhotic patient. The usual lipid abnormalities: considerable rise in free red cell cholesterol and lesser rise in phospholipid, regressed concommitantly to the disappearance of acanthocytes. No change in the main liver function tests was, however, observed. The etiological mechanisms of acanthocytosis in cirrhosis are probably multiple, and their interactions are compplex. The exchange of abnormal lipoproteins between the plasma and the red cell membrane is the last theory to be considered. On the other hand, no argument could explain the disappearance of the acanthocytosis, this phenomenon is considered up to now irreversible and a sign of the gravity of hepatic lesions.

Acanthocytes↗
PubMed1976

Scintillation splenoportography: hemodynamic and morphological study of the portal circulation.

The intrasplenic injection of 99mTc-labeled albumin microspheres, followed 30 sec later by an injection of 99mTc-labeled red blood cells with recording of the progression of the two tracers, were performed in 110 patients. This also enabled the plotting of activity versus time curves on splenic, hepatic, cardiac, and pulmonary areas of interest, there by giving access to several hemodynamic variables. Scintillation image demonstrated splenoportal obstruction in 8 cases. Intrahepatic obstruction with reflux via collaterals were observed in 53 cases, 14 with umbilical reflux. In 13 cases, the patency of surgical portacaval anastomoses were verified. The splenoportal blood flow velocity was not significantly different in patients with cirrhosis (V = 10.1 cm per sec +/- 3.0 SD) and in normal subjects (V = 13.2 cm per sec +/- 5.8 SD). The fraction of shunted splenic flow in the case of cirrhosis varied from 0 to 100%; there was no relationship between this percentage and the seriousness of the clinical status. In 3 cases, the presence of intrahepatic shunts was detected. There was a very significant difference between mean transit time (MTT) of red blood cells in patients with cirrhosis (t = 12.2 sec +/- 4.4 SD) and those without cirrhosis (t = 19.9 sec +/- 3.7 SD). Among patients with cirrhosis, those with a history of jaundice had a shorter MTT than those without such a history. On the other hand, the MTT was not significantly different whether the patients with cirrhosis had or did not have hemorrhage, ascites or encephalopathy. There was a positive correlation (P less than 0.01) between MTT and plasma albumin concentration,and between MTT and prothrombin (P less than 0.01). Finally, there was a high negative correlation (P less than 0.001) between MTT and total serum bilirubin. Scintillation splenoportography is a useful technique for assessing hepatic hemodynamics and for demonstrating abnormalities of the intrahepatic circulation.

Blood Flow Velocity↗
PubMed1975

[Selection of cell lines resistant to cyclic AMP and theophylline from murine plasmocytoma MOPC 173. Cross resistance to ouabain and concanavalin A].

Using cAMP or theophyllin as selective agents, we obtained from contact inhibited and non contact inhibited cell lines, derived from the same plasmocytoma, different resistant cell lines. All of them were cAMP and theophyllin resistant and also ouabain and con A resistant as judged by the growth curves in presence of the different drugs.

Cell Division↗
PubMed1975

Relationship between intracellular K+ concentrations and K+ fluxes in growing and contact-inhibited cells.

The K+ content and the K+ flux were measured in the cell lines ME2 and MF2 isolated from plasmocytoma MOPC 173. Both cell lines were shown to have the seem K+ content and the same K+ steady state flux per unit of surface area. In ME2 cells, no modification of the exchange movement was observed during contact inhibition. However, contact-inhibited cells exhibited an increased resistance to depletion, characterized by a lower K+ net movement. The (Na+ plus K+)-ATPase measured in homogenates is poorly correlated to in vivo cation fluxes both because of the enhancement due, presumably, to the drop of K+ concentration on the cytoplasmic face of the membrane and because of losses during preparation which can be conspicuous, especially in contact-inhibited cells. The K+ net flux is considerable increased when the intracellular K+ level is reduced after preincubation of the cells in a K+ -free medium. Thus, internal K+ seems to regulate the K+ influx.

Adenosine Triphosphatases↗