PubMed Health⌕ Search

Biomedical subjects

O C Barretto

Publications and source records attributed to O C Barretto.

At least 19 recordsLinked to original sources
PubMed2000

Enzymes and membrane proteins of ADSOL-preserved red blood cells.

CONTEXT: The preservative solution ADSOL (adenine, dextrose, sorbitol, sodium chloride and mannitol) maintains red cell viability for blood trans-fusion for 6 weeks. It would be useful to know about its preservation qualities over longer periods. OBJECTIVE: To determine some red cell biochemical parameters for peri-ods of up to 14 weeks in order to determine whether the red cell metabo-lism integrity would justify further studies aiming at increasing red cell preservation and viability. DESIGN: Biochemical evaluation designed to study red cell preservation. SETTING: São Paulo University erythrocyte metabolism referral center. SAMPLE: Six normal blood donors from the University Hospital of the Universidade Federal do Paraná, Curitiba, Brazil. MAIN MEASUREMENTS: Weekly assay of erythrocyte adenosine-5;-triphosphate (ATP), 2, 3-diphosphoglycerate (2,3DPG), hexokinase (HX), phosphofructokinase (PFK), pyruvate kinase (PK), glucose-6-phosphate dehydrogenase (G-6-PD), 6-phosphogluconic dehydrogenase (6-PGD), glyceraldehyde-3-phosphate dehydrogenase (GAPD), glutathione reduc-tase (GR), glutathione peroxidase (GSHPx), plasma sodium and potas-sium, blood pH, and membrane proteins of red cells preserved in ADSOL were studied during storage for 14 weeks storage. RESULTS: During ADSOL preservation, erythrocyte ATP concentration decreased 60% after 5 weeks, and 90% after 10 weeks; the pH fell from 6.8 to 6. 4 by the 14th week. 2,3-DPG concentration was stable during the first week, but fell 90% after 3 weeks and was exhausted after 5 weeks. By the end of the 5th week, an activity decrease of 16-30% for Hx, GAPD, GR, G-6-PD and 6-PGD, 35% for PFK and GSHPx, and 45% for PK were observed. Thereafter, a uniform 10% decay was observed for all enzymes up to the 14th week. The red blood cell membrane pro-teins did not show significant alterations in polyacrylamide gel electro-phoresis (SDS-PAGE) during the 14 weeks. CONCLUSION: Although the blood viability was shown to be poor from the 6th week up to the 14th week of storage due to ATP and 2,3-DPG depletion, the other biochemical parameters remained in fairly good condition for longer storage. As there is a gradual and uniform decay in activity throughout these 14 weeks, it seems that ADSOL-preserved red cells may be used as red cell enzyme standards and membrane proteins as well.

2,3-Diphosphoglycerate↗
PubMed2000

Increased fetal hemoglobin levels in patients infected with human immunodeficiency virus (HIV1/2).

Fetal hemoglobin was measured in HIV1/2 patients under treatment with combined therapy (zidovudine and a protease inhibitor). A total of 143 patients and 103 normal individuals were investigated by the quantitative method of Betke and the semi-quantitative acid elution method of Kleihauer. In the normal person, hemoglobin F makes up less than 1% and an increase higher than 1.5% was observed in 21.4% of HIV patients by the method of Betke and in 24.8% of HIV-infected patients by the method of Kleihauer. The quantitative biochemical method of Betke showed that the populations were significantly different (two-tailed Mann-Whitney test). The reason for this hemoglobin F increase might be ascribed to the effect of zidovudine or to direct viral action on gamma chain expression. The finding of a higher F cell frequency indicated by the method of Kleihauer rather suggests that there is an increased F cell clone proliferation rather than an increase in hemoglobin F level in every cell.

Anti-HIV Agents↗
PubMed1999

The erythrocyte cytoskeleton protein 4.2 is not demonstrable in several mammalian species.

Erythrocyte membrane proteins from 44 representative mammals were studied. Protein 4.2 was not detected in guinea pigs (Cavia porcellus) (N = 14), Southern Brazilian swamp large rats (Myocastor coypus) (N = 2), cutias (Dasyprocta sp) (N = 4), and horses (Equus caballus) (N = 13). These animals also presented high ankyrin concentrations except for the horse which did not exhibit a sharp band, although minor components located between proteins 2 and 3 could account for the ankyrin family. The rodents studied did present band 6, which was not detectable in other common rodents such as white rats (Rattus norvegicus) (N = 9) and mice (Mus musculus) (N = 12). Since the absence of protein 4.2 does not disrupt the cytoskeleton membrane, we suggest that it is not an essential protein. Its absence may be compensated physiologically by the higher ankyrin concentration observed.

Animals↗
PubMed1998

Erythrocyte glucose-6-phosphate dehydrogenase activity assay and affinity for its substrate under "physiological" conditions.

Glucose-6-phosphate dehydrogenase (G6PD) activity and the affinity for its substrate glucose-6-phosphate were investigated under conditions similar to the physiological environment in terms of ionic strength (I: 0.188), cation concentration, pH 7.34, and temperature (37 degrees C). A 12.4, 10.4 and 21.4% decrease was observed in G6PD B, G6PD A+ and G6PD A- activities, respectively. A Km increase of 95.1, 94.4 and 95.4% was observed in G6PD B, G6PD A+ and G6PD A-, respectively, leading to a marked decrease in affinity. In conclusion, the observation of the reduced activity and affinity for its natural substrate reflects the actual pentose pathway rate. It also suggests a much lower NADPH generation, which is crucial mostly in G6PD-deficient individuals, whose NADPH availability is poor.

Blood Physiological Phenomena↗
PubMed1997

Correlation of discocyte frequency and ATP concentration in preserved blood. A morphological indicator of red blood cell viability.

Red blood cells (RBC) are viable if kept in an adequate preservative solution, although gradual changes in morphology and metabolism may occur. There is a gradual decrease in adenosine-5'-triphosphate (ATP) concentration, pH, glucose consumption, and enzyme activity during preservation. The normal discocyte shapes are initially replaced by echinocytes and stomatocytes and, at final stages, by spherocytes, the last step before splenic sequestration. Post-transfusional survival has been correlated with the ATP concentration. RBC preserved in ADSOL, a solution containing adenine, dextrose, sodium chloride, and mannitol, are viable for transfusion for up to 6 weeks. Erythrocytes from 10 blood units taken from healthy adult donors were preserved for 12 weeks in ADSOL at 4 degrees C. We now report a significant correlation (r2 = 0.98) between the percentage of discocytes (89 to 7%) and ATP (100 to 10%) concentration in ADSOL-preserved RBC. The results suggest that the percent of discocyte shapes used as an indicator of ATP concentration may be a useful indicator for quality control of RBC viability in centers which have limited assay facilities.

Adenosine Triphosphate↗
PubMed1996

Vitamin dependent erythrocyte enzymes in newborns in relation to gestational age and birth weight.

In order to search for any difference in riboflavin and pyridoxine nutrition between term appropriate for gestational age (TAGA), term small for gestational age (TSGA) and preterm appropriate for gestational age (PTAGA) newborns, cord blood from 23, 19 and 20 infants, respectively, were studied, and red cell glutathione reductase (riboflavin-dependent) and glutamic oxaloacetic transaminase (pyridoxine-dependent) activities were measured, as well as their respective activity coefficients (GRase AC and GOT AC). Red cell enzymes were assayed according to BEUTLER [4] in a Gilford recording spectrophotometer model 2451 at 37 degrees C. Values of 1.42, 1.39 and 1.32 of GRase AC and values of 1.17, 1.02 and 1.08 GOT AC, respectively were obtained. These data indicate that there is no significant difference between the three categories of newborns with regard to riboflavin and pyridoxine nutrition, and suggest that neither maturity nor adequacy of intrauterine growth were related to differences in the availability of these vitamins. All groups demonstrate a uniform mild deficiency of riboflavin and an adequate level of pyridoxine, probably the effect of maternal diet.

Aspartate Aminotransferases↗
PubMed1995

Physiological red cell, 2,3-diphosphoglycerate increase by the sixth hour after birth.

As the available hemoglobin A1 at birth ranges from 20 to 30% a possible mechanism to favor oxygen release to the tissues could be a decrease of hemoglobin A1 affinity to oxygen. This may be accomplished by an increase in blood pH soon after birth and by an elevation in red cell 2,3-diphosphoglycerate (2,3-DPG). This hypothesis is supported by Valleri and Hirsch, who described a rapid 2,3-DPG recovery of transfused depleted 2,3-DPG red cells. That being so, we carried out this current study by assaying the 2,3-DPG of cord blood from 22 newborns and at 6, 24 and 72 hours after birth, as well as those enzymes assumed to be envolved in the 2,3-DPG levels regulation. 2,3-DPG (nmoles g-1 Hb) demonstrated the following values: cord blood: 9,770 +/- 1,026; 6h: 12,773 +/- 1,726; 72 h: 11,990 +/- 728, unveiling a distinct behavior of a sharp increase of 30% by the sixth hour. This confirmed our hypothesis. Regarding the metabolic mechanisms which can account for the 2,3-DPG increase, besides the rise of blood pH, we detected a significant decrease of the 2,3-DPG phosphatase activity, which might diminish the 2,3-DPG breakdown.

2,3-Diphosphoglycerate↗
PubMed1993

Genetic and environmental effects on blood cells.

In a sample of 105 concordant sex MZ and DZ twin pairs, the following characteristics were measured: red cell count, haemoglobin concentration, package cell volume, mean cell volume, mean cell haemoglobin, mean cell haemoglobin concentration, reticulocytes, platelets, white cell count and the six types of leucocytes, lymphocytes, monocytes, band and segmented neutrophils, eosinophils and basophils. The statistical model employed in the univariate twin analysis allows for three sources of variation: genetic (h2), shared environmental (c2) and specific environmental influences (e2). A genetic component was significant for red cell count, haemoglobin and mean cell haemoglobin (0.64, 0.60 and 0.46 respectively), with heritable variation suggested for package cell volume, mean cell volume, mean cell haemoglobin, lymphocytes and monocytes. Shared environmental variation was only present for neutrophils.

Blood Cells↗
PubMed1992

[The prevalence of iron deficiency in pregnant women at their first consultation in health centers in a metropolitan area, Brazil. Etiology of anemia].

Three hundred and sixty-three pregnant women enrolled in the Pregnancy Medical Care Program of S. Paulo Health Department in the district of Butantan, S. Paulo city, Brazil, were studied at their first routine consultation between April and October, 1988. Their average age was 25 and 65.9% of them belonged to families with a monthly income below US$50.00 per capita. Only 3.1% presented an income above US$150.00 per capita. Taking the minimum transferrin saturation threshold of 15% as determining iron deficiency, a 4.6% prevalence of iron deficiency was observed in the first trimester, 17.3% in the second trimester and 42.8% in the third trimester, resulting in an overall prevalence of 12.4%. There was no significant difference between prevalences of iron deficiency according to the number of pregnancies. The prevalence of iron deficiency was higher in women presenting incomes below US$50.00 per capita.

Adult↗
PubMed1991

Gd(-) Carapicuiba, a rare glucose-6-phosphate dehydrogenase variant associated with moderate enzyme deficiency and chronic hemolysis.

1. A 27 year old Brazilian male of both Portuguese and Spanish origin presenting nonspherocytic chronic hemolytic anemia was found to have a rare glucose-6-phosphate dehydrogenase variant herein named Gd(-) Carapicuiba. 2. The red blood cell enzyme variant is characterized by a moderate enzyme deficiency (47%), high Km for its substrates G6P and NADP, decreased activity against deamino-NADP, increased Ki for NADPH and decreased heat stability. 3. The clinical signs of the patient are probably related to these properties of the enzyme variant.

Adult↗
PubMed1990

Red cell enzymes and intermediates in AGA term newborns, AGA preterm newborns and SGA term newborns.

Red cell enzyme activities and 2,3-diphosphoglycerate and adenosine-triphosphate levels in cord blood of three groups of newborn infants were studied. The groups were classified according to birthweight in relation to intrauterine growth and gestational age. Only phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase and enolase activity values differed significantly among the groups. The activity of phosphofructokinase was lower in small-for-date term infants (TSGA) and preterm adequate for gestational age (PTAGA) in comparison to term infants adequate for gestational age (TAGA). Glyceraldehyde-3-phosphate dehydrogenase activity was higher in TAGA, in comparison to PTAGA, with no other difference among the groups. Enolase activity was found to be higher in TSGA compared to TAGA and higher in PTAGA compared to TAGA. No differences were found between PTAGA and TSGA.

Erythrocytes↗
PubMed1990

[The prevalence of anemia in pregnant women in their first visit to health centers of a metropolitan area, Brazil].

Three hundred and sixty-three pregnant women enrolled in the Pregnancy Medical Care Program of S. Paulo Health Department from the district of Butantan, S. Paulo city, Brazil, were studied at the first routine consultation. At the time they were examined they were not given any medicine containing iron, folic acid or vitamin B12. Their average age was 25 and 65.9% belonged to families with a monthly per capita income below US$ 50.00. Only 3.1% had a per capita income above U$$ 150.00. The prevalence of anemia was 12.4%. The hemoglobin concentration (grams/dl) in the first trimester was significantly higher than in the second and third trimester of pregnancy. The prevalence of anemia in the first trimesters (3.6%) was significantly smaller than that found in the second (20.9%) and third semesters (32.1%). Those women who had had more than three gestations presented a higher prevalence of anemia than those with less than three, and the prevalence of anemia was higher in the group whose families had a monthly per capita income below US$ 25.00.

Adolescent↗
PubMed1988

Metabolism and preservation of fresh and stored erythrocytes in blood treated with gentian violet.

1. The metabolism of the erythrocytes in the gentian violet (GV)-treated blood from ten donors was studied weekly from time zero to the 28th day of storage in order to evaluate the efficacy of the use of GV in the chemoprophylaxis of transfusional Chagas' disease. 2. Adenosine triphosphate (ATP) levels in erythrocytes of GV-treated blood were similar to the control until and including the 21st day, with a significant decrease of approximately 40% in relation to control detected only on the 28th day. 2,3-Diphosphoglycerate levels of GV-treated blood significantly decreased from the 21st to the 28th day in relation to the control. However, they were above the minimum accepted for good preservation. pH, partial oxygen pressure (pO2), partial carbon dioxide pressure (pCO2), sodium and potassium levels were similar to the respective controls. 3. The use of gentian violet in the chemoprophylaxis of transfusional Chagas' disease is strongly recommended in endemic areas and/or where no safe serologic tests are available.

2,3-Diphosphoglycerate↗
PubMed1987

Gd(+)Cuiabá, a new rare glucose-6-phosphate dehydrogenase variant presenting normal activity.

A 33-year-old Brazilian male of Portuguese extraction was found to have a new glucose-6-phosphate dehydrogenase variant, herein named Gd(+)Cuiabá. The enzyme variant is characterized by normal activity, normal electrophoretic mobility, high Km for glucose-6-phosphate, high Ki for NADPH, decreased thermal stability, normal utilization of substrate analogues and normal pH curve.

Adult↗
PubMed1986

Acquired erythroenzymopathy in a monozygotic twin with acute myeloid leukemia.

The specific activity of several red cell enzymes was studied in a pair of monozygotic twins, one of whom presented acute myeloblastic leukemia. When the intrapair variation of these twins was compared with that of a series of nine normal twins, a significant decrease in phosphoglycerate kinase, diphosphoglycerate mutase, pyruvate kinase, lactic dehydrogenase, adenylate kinase and glucose-6-phosphate dehydrogenase activities and an increase in 6-phosphogluconate dehydrogenase activity were demonstrable for the leukemic twin. The heat stability of the leukemic proband's pyruvate kinase at pH 8.0 and 56 degrees C was less than that of the normal twin, suggesting an acquired qualitative disorder.

Adenylyl Cyclases↗
PubMed1985

Erythrocyte sorbitol dehydrogenase of selected non-mammalian vertebrates.

Erythrocyte sorbitol dehydrogenase activity (EC 1.1.1.14) from selected non-mammalian vertebrates was studied showing great variability not related to their phylogenetical position. The Michaelis-Menten constant (Km) for sorbitol exhibited moderate low values in the studied animals. In snakes the Km for sorbitol was low with moderate activity of sorbitol dehydrogenase, suggesting that the enzyme could reach maximum activity with lower sorbitol concentration in comparison to other vertebrates. In the snakes the enzyme showed the same affinity for all the studied polyols, indicating that we are probably dealing with a very ancient enzyme, an unspecific enzyme.

Animals↗