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Biomedical subjects

F Vertongen

Publications and source records attributed to F Vertongen.

64 records · Page 4Linked to original sources
PubMed1984

Immobilized pH gradients and reversed-phase high-performance liquid chromatography: a strategy for characterization of haemoglobin variants with electrophoretic mobility identical to that of Hb A. The case of Hb San Diego.

The preparative aspects of immobilized pH gradients applied to abnormal haemoglobins (Hb) is described. As shown with the example of Hb San Diego, this method is successful even with as small a difference in pHi as 0.01 pH unit. For characterization of such neutral variants, reversed-phase high-performance liquid chromatography is demonstrated to be a very efficient tool.

Amino Acids↗
PubMed1984

Enzymes of purine metabolism in B-chronic lymphocytic leukemia.

In order to study if enzymes of purine metabolism could be used as cell markers in B-chronic lymphocytic leukemia (B-CLL), the activities of adenosine deaminase (ADA), purine nucleoside phosphorylase (PNP), and 5'-nucleotidase (5'N) were repeatedly measured in blood mononuclear cells from B-CLL patients and were compared to those obtained in normal controls. Enzyme activities in patients were also compared to other biological parameters indicative of B-CLL to activities of ADA and PNP in erythrocytes. Results show that B-leukemic cells display abnormal enzyme patterns: subnormal ADA activity is characteristic; 5'N activity is depressed in 60% of the cases but increased in 15%. An inverse relationship between PNP activity and corresponding lymphocytosis is observed in leukemic but not in normal cells. The enzymatic anomalies seem to be linked to the presence of an unusual peripheral lymphocytic population, induced by the leukemic process. Indeed, ADA and PNP are not abnormal in erythrocytes. In untreated nonevolutive patients, the enzyme profile tends to remain stable throughout the course of the illness; normalization of enzyme patterns in treated patients occurs only when therapy induces improvement in T and B cell distribution.

5'-Nucleotidase↗
PubMed1984

Hemodynamic effects of vasopressin, alone and in combination with nitroprusside, in patients with liver cirrhosis and portal hypertension.

We have investigated the effects on systemic, pulmonary, hepatic, and renal hemodynamics, and on blood gases of vasopressin, 0.4 U/min I.V. first alone, then in combination with nitroprusside 1-5 micrograms/kg/min I.V., in 12 patients with liver cirrhosis and portal hypertension. Portal pressures were estimated by the gradient between occluded and free hepatic vein pressures, hepatic blood flow was measured by indocyanine green infusion, renal blood flow by an isotopic method, and cardiac output by thermodilution. Vasopressin alone reduced cardiac output (-23%) and O2 delivery to the tissues (-25%), increased mean arterial pressure (+20%) and filling pressures of the heart (+136%), reduced portal pressures (-36%) (from 19 +/- 1 to 12 +/- 1 mmHg, mean +/- SEM), hepatic blood flow (-35%) (1.33 +/- 0.2 to 0.87 +/- 0.1 l/min), and renal blood flow (-16%) (0.77 +/- 0.07 to 0.65 +/- 0.05 l/min). Adding nitroprusside restored cardiac output, preload and afterload, and renal blood flow to pretreatment values. Oxygen delivery remained depressed (-12%) because of a negative effect on pulmonary gas exchange (physiologic shunt increased from 16 +/- 2 to 28 +/- 4%). Portal pressures remained reduced by 31% and hepatic blood flow by 25%. These results suggest that small doses of I.V. nitroprusside minimize the deleterious hemodynamic effects of vasopressin while maintaining the therapeutic benefit of portal pressure reduction in cirrhotic patients.

Adult↗
PubMed1984

Methylthioadenosine phosphorylase and purine nucleoside phosphorylase in B-chronic lymphocytic leukemia.

Enzymes of purine metabolism have potential utility as biological markers of normal lymphocytes and their neoplastic counterparts. The activity of two of them, methylthioadenosine phosphorylase (MTA phosphorylase) and purine nucleoside phosphorylase (PNP) were measured in peripheral mononuclear cells from 11 patients with B-chronic lymphocytic leukemia (B-CLL) and compared with those obtained in cells from 10 normal volunteers. An inverse relationship between the two phosphorylases was demonstrated in patients, with higher MTA-phosphorylase and lower PNP activities than in control subjects.

Adult↗
PubMed1984

Thymidine kinase and thymidine phosphorylase activities in various types of leukaemia and lymphoma.

Thymidine kinase (TK) isoenzymes and thymidine phosphorylase (TP) activities have been measured in peripheral mononuclear cells of patients with acute lymphoblastic and monoblastic leukaemia or B-chronic lymphocytic leukaemia, as well as in normal subjects, and also in lymph node cells from patients with non-Hodgkin's lymphoma, with Hodgkin's disease and with benign adenopathies. TK1 isoenzyme activity was highest in acute lymphoblastic leukaemia and in centroblastic lymphoma. Then in progressively decreasing order appeared the Hodgkin's disease values, the centroblastic centrocytic lymphoma values and the benign reactive lymph node cell values. When compared to normal blood mononuclear cells, TP was greatly decreased in acute lymphoblastic leukaemia and slightly but significantly decreased in chronic leukaemia. Monoblastic cells exhibited a unique enzyme pattern; moderately increased TK1 activity and high TP activity. Our results suggest that both enzymes are indicative of the maturation status of leukaemic cells from B lineage. They demonstrate that in lymph node cells, TK1 reflects the proliferative status of both malignant and non-malignant cells and that in monoblastic cells the synthesis of dTMP through de novo synthesis is favoured.

Humans↗
PubMed1982

In vitro study of the incorporation and transport of nonesterified fatty acids into the phospholipids of the red blood cell membranes of cystic fibrosis patients.

The in vitro incorporation and transport of plasma nonesterified fatty acids into phospholipids of red cell membranes have been studied in cystic fibrosis and healthy children. Red blood cells were labeled in vitro by an active "acyltransferase"-dependent incorporation of radioactively labeled nonesterified fatty acids. [3H]-Palmitic and [14C]-linoleic acid, bound to albumin, have been studied simultaneously because it has been shown before that the concentration of palmitic acid increases and the concentration of linoleic acid decreases both in the plasma nonesterified fatty acid fraction and in the various phospholipids of the erythrocyte membranes of cystic fibrosis patients. The labeled cells were reincubated in autologous serum and the radioactivity present in the serum lipids and in the major phospholipid fractions of the erythrocyte membranes was measured. A general conclusion is that the in vitro turnover of labeled palmitic and linoleic acids in the phospholipids of the erythrocyte membranes is higher for cystic fibrosis patients than for healthy children. No difference is detectable between the in vitro behaviour of [14C]-linoleic versus [3H]-palmitic acid in cystic fibrosis patients compared with healthy children.

Biological Transport↗
PubMed1981

Oxidative haemolysis in protein malnutrition.

A study of the haemolytic anaemia observed in protein-energy malnutrition (PEM) in Kivu disclosed the following results. The in vitro resistance to oxidative aggressions of PEM patients' erythrocytes was decreased: when incubated with acetylphenylhydrazine, a higher percentage of the cells showed Heinz bodies, as compared with erythrocytes of local controls. Normal or increased activities were found for certain erythrocyte enzymes involved in the detoxification of activated oxygen: glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and glutathione reductase. The level of reduced glutathione was not decreased. Reduced activities were observed for two enzymes containing trace elements: glutathione peroxidase and superoxide dismutase. It is suggested that the shortened erythrocyte lifespan observed in PEM patients corresponds to an oxidative process which results from the decrease of both enzyme activities. The hypothesis that depletion of trace elements could be responsible for the decreased activity of those enzymes is discussed.

Adolescent↗
PubMedDate not supplied

Malabsorption of liposoluble vitamins in a child with bile acid deficiency.

A male born to first cousins presented at 12 months with hypocalcemic convulsions, rickets, epistaxis due to vitamin K deficiency, and extremely low serum levels of beta-carotene and vitamin A. Liver function was altered moderately (glutamic-oxaloacetic transaminase, 55 U/L; glutamic-pyruvic transaminase, 37 U/L; lactate dehydrogenase, 255 U/L; alkaline phosphatase, 437 U/L). To correct the deficiencies, 8,000 IU vitamin D/day, 10,000 IU vitamin A/day, and intramuscular administration of vitamin K1 were required. At 9 years, he presented signs of neuromuscular affection, and the serum vitamin E level (measured for the first time) was extremely low. Classic lipid malabsorption syndromes (abetalipoproteinemia, chronic cholestasis, mucoviscidosis, coeliac disease, Whipple's disease) were excluded by appropriate examinations. Composition of duodenal bile acids was characterized by undetectable levels of cholic acid metabolites, and only chenodeoxycholic acid metabolites were present. Serum total bile acid concentration was normal, with an atypical low cholic acid/chenodeoxycholic acid ratio and abnormal presence of 3 beta-OH-delta 5-cholenic acid and 6-OH-bile acids. Urinary bile acid composition was also characterized by elevated 6-OH-bile acids. Known enzymopathies of the bile acid synthetic pathway were excluded (cerebrotendinous xanthomatosis, cerebro-hepato-renal syndrome of Zellweger, coprostanic acidemia). Bile acid pool sizes were determined by using stable isotopes: cholic acid pool size [2.90 (N, 32 +/- 16) microM/kg] and chenodeoxycholic acid pool size [10.8 (N, 32.6 +/- 9.9) microM/kg] were extremely low; fractional turnover rates of both bile acids were in a normal range.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗