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Biomedical subjects

R Rosa

Publications and source records attributed to R Rosa.

At least 109 records · Page 6Linked to original sources
PubMed1981

Embryonic and fetal hemoglobin synthesis in K562 cell line.

K562 cell line was grown in liquid suspension and in plasma clot cultures. Morphological studies revealed the presence of a minority of cells, which were identified as erythroblasts. However, the majority of the cells remained unidentified. Biochemical studies confirmed the synthesis of hemoglobin by K562 cells. The pattern of hemoglobin (Hb) production was of the embryonic type, with the presence of small amount of fetal Hb. The addition of several inducers, like Epo and butyrate, was unable to modify the pattern of Hb production of K562. In contrast, the addition of hemin increased the synthesis of Hb and stimulated the synthesis of fetal Hb and probably adult Hb.

Butyrates↗
PubMed1980

Pyruvate kinase hyperactivity genetically determined metabolic consequences and molecular characterization.

Four people from the same family with red cell pyruvate kinase (PK) hyperactivity are described. These people displayed low 2,3-diphosphoglycerate (2,3-DPG) and high adenosine triphosphate (ATP) levels. In vitro metabolism studies of their red cells showed the relationship between the PK activity, low 2,3-DPG, and high ATP levels. The PK electrophoretic pattern of these subjects was abnormal by the presence of several additional bands; one of them migrated like PKM2. PKR from these people was thermounstable and M2-like PK was identical to PKM2 for immunologic reactivity and KO, 5s for phosphoenolpyruvate.

Adenosine Triphosphate↗
PubMed1979

Hormonal regulation of active chloride transport in the dogfish rectal gland.

Active transport of chloride is modulated by cyclic AMP in the rectal gland of Squalus acanthias. Vasoactive intestinal peptide (VIP) specifically activates the production of cyclic AMP by the gland and stimulates the secretion of chloride. Somatostatin inhibits VIP-induced secretion but has no effect alone. Both these peptides are present in the dogfish shark and may play an important role in electrolyte homeostasis.

Animals↗
PubMed1978

The first case of a complete deficiency of diphosphoglycerate mutase in human erythrocytes.

An inherited and complete deficiency of diphosphoglycerate mutase was discovered in the erythrocytes of a 42-yr-old man of French origin whose blood hemoglobin concentration was 19.0 g/dl. Upon physical examination he was normal with the exception of a ruddy cyanosis. The morphology of his erythrocytes was also normal and there was no evidence of hemolysis. The erythrocyte 2,3-diphosphoglycerate level was below 3% of normal values and, as a consequence, the affinity of the cells for oxygen was increased. Diphosphoglycerate mutase activity was undetectable in erythrocytes as was that of diphosphoglycerate phosphatase. The activities of all the other erythrocyte enzymes that were tested were normal except for nomophosphoglycerate mutase which was diminished to 50% of the normal value. The levels of reduced glutathione, ATP, fructose 1,6-diphosphate, and of triose phosphates were elevated, whereas those of glucose 6-phosphate and fructose 6-phosphate were decreased. This report sheds new light on the role of diphosphoglycerate mutase in the metabolism of erythrocytes.

Adult↗
PubMed1977

Electrophoretic and kinetic studies of human erythrocytes deficient in pyrimidine 5'-nucleotidase.

A new case of a defect in red cell pyrimidine 5'-nucleotide (P5N) activity was found in a large family from Guadeloupe in the West Indies. The propositus presented a characteristic hemolytic anemia with red cell basophilic stippling, an increased GSH level, and a shift of the peak in absorbance of nucleotide. The enzyme activity from the deficient red cells differed from that of the normal. The P5N activity of the deficient red cells was about 14% that of normal. The electrophoretic pattern of P5N activity of the deficient red cells was distinct from that of the control in terms of its Km and of the effects of pH on its maximum activity and heat stability. The significance of such differences is discussed.

Anemia, Hemolytic, Congenital↗
PubMed1977

Electrophoretic characterization of pyrimidine 5'-nucleotidase of human erythrocytes and its distinction from acid phosphatase.

Electrophoresis of red cell pyrimidine 5'-nucleotidase was carried out on cellulose acetate strips. One major band of activity was found in preparations from human erythrocytes. This enzyme showed a specificity for the pyrimidine nucleotides UMP and CMP. No activity was detected with AMP. Pyrimidine 5'-nucleotidase activity could be separated from that of acid phosphatase with the use of alpha-glycerophosphate. This method may be useful in the study of pyrimidine 5'-nucleotidase deficiency in red cells.

Acid Phosphatase↗
PubMed1976

Erythrocyte enzyme activities in diploid and triploid salamanders (Pleurodeles waltlii) of both sexes.

Studies of several enzyme activities and of some metabolites in erythrocytes of the newt Pleurodels waltilii are described. The results indicate that differences exist between enzyme activities in males and females and in diploid and triploid animals. Females have higher erythrocyte enzyme activities than males. However, triploid animals have lower enzyme activites in their erythrocytes than diploid animals; this observation is more striking in females than in males.

Alleles↗
PubMed1975

Evidence for three enzymatic activities in one electrophoretic band of 3-phosphoglycerate mutase from red cells.

Electrophoresis of 3-phosphoglycerate mutase from erythrocytes of man and several animal species has been performed on cellulose acetate strips. In most cases the electrophoretic pattern of this enzymatic activity shows three bands. 2,3-diphosphoglycerate phosphatase and diphosphoglycerate mutase from erythrocytes of the same species have been revealed after migration during the same electrophoresis. We found that the band of 2,3-diphosphoglycerate phosphatase and the band of diphosphoglycerate mutase activities migrate at the same level as one of the bands corresponding to 3-phosphoglycerate mutase. Here, we discuss the possible existence of a single molecule carrying three enzymatic activities.

Animals↗