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Biomedical subjects

B Zachara

Publications and source records attributed to B Zachara.

At least 19 recordsLinked to original sources
PubMed1986

Effect of dipyridamole on adenosine incorporation into hypoxanthine nucleotides of fresh human red cells.

Fresh human red cells were incubated for 2 hours in a medium containing adenosine, pyruvate and inorganic phosphate (APP medium), or in APP medium supplemented with 10(-4) M dipyridamole (APPD medium). No measureable amount of ITP was found in fresh red cells, and the average IMP content in these cells was 0.18 +/- 0.09 mumol/g Hb. After 2 hours incubation in APP medium, the IMP content increased almost 8.5-fold to 1.52 +/- 0.78 mumol/g Hb. Under these conditions the ITP level also increased to 1.40 +/- 0.84 mumol/g Hb. After 2 hours incubation of red cells in APPD medium, the average IMP content increased to 5.30 +/- 2.33 mumol/g Hb, about 3.5 times that found in APP medium. At the same time ITP content was about 53.6% lower, that is 0.65 mumol/g Hb. In red cells incubated in APPD medium, penetration of 8-14C-adenosine decreased by 50%, and incorporation of this nucleotide into the pool of all free nucleotides also decreased by 18.2% as compared to red cells incubated in APP medium. It is concluded that IMP is probably formed directly from AMP gained by the phosphorylation of adenosine during its penetration.

Adenosine↗
PubMed1986

Effect of dipyridamole on adenine incorporation into hypoxanthine nucleotides of fresh red blood cells.

An investigation was carried out on the penetration of [8-14C]adenine into fresh human red blood cells and of adenine incorporation into hypoxanthine nucleotides of red blood cells incubated in: 1) a medium containing adenosine, pyruvate, inorganic phosphate and NaCl, and 2) APP medium containing 1 X 10(-4) M dipyridamole (APPD medium). It was found that dipyridamole inhibits by about 45% the penetration of adenine into the red blood cells, and by 18% the incorporation of the isotope into the nucleotides of the cells under study. The inhibition of nucleotide synthesis and incorporation of the isotope into them did not apply to IMP, whose content--following erythrocyte incubation in APPD medium--increased 3.5 times, i.e. from 1.52 to 5.30 mumole/g Hb. At the same time there was an increase of the isotope count from 0.12% in IMP isolated from APP incubated erythrocytes to 0.34% in IMP synthesized in APPD incubated erythrocytes. Erythrocyte incubation in APPD medium reduced ITP synthesis by about 53% relative to its synthesis observed after erythrocyte incubation in APP medium equal to 1.40 mumole per g Hb.

Adenine↗
PubMed1984

Red blood cell glutathione peroxidase activity in multiple sclerosis.

Glutathione peroxidase (GSH-Px) activity of red blood cells of 23 multiple sclerosis (MS) patients (10 men and 13 women, aged 22-64 years) was examined and compared to the enzyme activity of 26 healthy persons (15 men and 11 women, aged 19-50 years). It was found that the mean GSH-Px activity was significantly higher (P less than 0.001) in red blood cells of MS patients (39.1 +/- 8.1 IU/g Hb) as compared to the group of healthy persons (25.9 +/- 5.2 IU/g Hb). There was no difference according to sexes in both the MS patients and the control group. The results are discussed based on the hypothesis that organic peroxides play a role in the etiology of multiple sclerosis.

Adult↗
PubMed1983

2,3-diphosphoglycerate concentration in the red blood cells of anaemic pregnant women in various periods of pregnancy.

The purpose of this study was to examine the intraerythrocytic 2,3-diphosphoglycerate (2,3-DPG) concentration in anaemic (haemoglobin concentration below 10.5 g/100 ml blood) and in normal pregnant women (haemoglobin concentration above 12.5 g/100 ml blood). The authors showed that the 2,3-DPG concentration increased systematically between the 16th and 42nd weeks of pregnancy, both in the control group and in pregnant women with anaemia. However, in the group of anaemic pregnant women the 2,3-DPG concentration was higher in each stage of pregnancy.

Adult↗
PubMed1983

Relation between 2,3-diphosphoglycerate concentration in maternal red cells and duration of labour and newborn birth weight in anaemic pregnant women.

We have found a high negative correlation between the 2,3-DPG level and the duration of labour (r = -0.586). The correlation between red cell 2,3-DPG concentration and newborn birth weight was 0.576. Both relations are statistically significant with p less than 0.01. These results suggest that the increased 2,3-DPG concentration in maternal red cells facilitates the release of oxygen to uterine muscle and to the foetus and thus helps the normal intrauterine development of foetus and reduces the duration of labour.

2,3-Diphosphoglycerate↗
PubMed1981

Activity of inosine triphosphate pyrophosphohydrolase in fresh and stored human erythrocytes.

The accumulation of inosine triphosphate (ITP) in human erythrocytes incubated with inosine depends on the activity of inosine triphosphate pyrophosphohydrolase (ITPH). High activity of this enzyme is accompanied by a low concentration of ITP and conversely. We showed that ITPH activity decreases with the prolongation of blood preservation time. As a consequence there is a lower accumulation of ITP in fresh erythrocytes incubated in a medium containing high concentrations of inosine, pyruvate and phosphate (IPP) than in red blood cells preserved at 4 degrees C. Synthesis of ITP in erythrocytes incubated in IPP medium being so intensive, it seems possible that during incubation an intermediate accumulates which decreases ITPH activity.

Blood Preservation↗
PubMed1981

Hypoxanthine nucleotides synthesis in fresh and stored human erythrocytes.

Human erythrocytes incubated in inosine-pyruvate-phosphate (IPP) medium are able to accumulate great amounts of inosine monophosphate (IMP) and inosine triphosphate (ITP). Accumulation of ITP is low in freshly drawn cells. It increases during blood storage in acid-citrate-dextrose solution. Addition of labelled inosine or hypoxanthine to the IPP medium allowed to show the synthesis of small amounts of inosine diphosphate and the appearance of radioactivity in the ATP fraction. Conditions of incubation and the pathways of hypoxanthine nucleotides synthesis are discussed.

Blood Preservation↗
PubMed1981

Concentration of 2,3-diphosphoglycerate and adenosine triphosphate in erythrocytes following acute blood loss in the beagle.

The effect of experimental anaemia induced by phlebotomy and the effect of infusion of various fluids on the 2,3-DPG, ATP and total organic phosphate (Porg) concentration were examined in the red cells of beagles made anaemic by withdrawal of 30% of the circulating blood. Particular groups of dogs 30 min after phlebotomy were infused with own blood, blood with inosine, pyruvate and phosphate (IPP), Fluigel and Fluigel with IPP. The changes were most distinct in dogs which were not infused with any fluid. After 24 hours the content of 2,3-DPG, ATP and Porg increased by 17, 27 and 20%, respectively, in comparison with the results obtained before blood loss. Twenty-four hours following the reinfusion of own blood, a slight increase occurred in the 2,3-DPG and Porg content. Infusion of Fluigel caused a decrease of the phosphate compounds concentration after 3 and 6 hours and then the concentration almost returned to normal. Infusion of own blood as well as Fluigel enriched with inosine, pyruvate and phosphate did not lead to any change in 2,3-DPG concentration. The red cells of dogs do not utilize inosine for 2,3-DPG or nucleotide synthesis. The increased cardiac output seems to the main mechanism for oxygen transport to tissues after an acute haemorrhage.

2,3-Diphosphoglycerate↗
PubMed1975

The effect of inosine, pyruvate, and inorganic phosphate on 2,3-diphosphoglycerate, adenine, and hypoxanthine nucleotide synthesis in outdated human erythrocytes.

Phosphate compounds of red cells stored at 4 degrees C. in acid-citrate-dextrose solution for 15 to 44 days, incubated at 37 degrees C. for 2 and 4 hours with inosine, pyruvate, and inorganic phosphate, and then stored for 2 weeks have been examined by ion-exchange column chromatography. After 2 and 4 hours of incubation the 2,3-diphospholycerate level increased to 1,385 and 1,819 mumoles per 100 ml. of erythroeytes, respectively. After 4 hours of incubation the content of AIP increased to about 80 per cent of the physiologic level, while the content of AMP and ADP decreased considerably. These data suggest that the elevation of ATP is in part connected with the phosphorylation of AMP and ADP. The incorporation of inosine or hypoxanthine into the IMP and ITP has been proved. Four hours incubation period caused the synthesis of IMP and ITP to the mean value of 187 and 141 mumoles per 100 ml. of erythrocytes, respectively. No evidence of IDP formation was observed during the chromatographic separations of erythrocytic phosphate compounds. Storage of the erythrocyte suspension which has been incubated for 4 hours leads to the slower decomposition of 2,3-diphosphoglycerate, ATP, ITP, and IMP, and to the increase of AMP and ADP.

Adenine Nucleotides↗