Red Cell Glycolytic Intermediates Research Articles

Lead poisoning: clinical, biochemical, and haematological aspects of a recent outbreak.

The clinical, biochemical, and haematological aspects of a recent outbreak of lead poisoning, in which exposure was related to the oxyacetylene cutting of red lead painted ironwork, were investigated. Initial suspicion was raised when a blood film showed punctate basophilia which remains a simple and useful method of picking up lead toxicity. Estimations of blood lead concentration and conventional laboratory data confirmed the diagnosis. Although there was prominent punctate basophilia, spectrophotometric analysis showed only negligible accumulation of pyrimidine-5'-nucleotides despite severe suppression of pyrimidine-5'-nucleotidase activity. The pattern of the red cell glycolytic intermediates, investigated for the first time, suggested that lead may also affect glycolysis at the hexokinase step. Once the diagnosis was made intravenous chelation treatment was begun with a rapid improvement in symptoms. Long term follow up is required to assess any sequelae of intoxication. These cases emphasise the classic features of lead poisoning, and despite the currently available diagnostic tests, lead intoxication may still go unrecognised unless a thorough occupational history is taken.

Red cell glycolytic intermediates in normal, anaemic and transfused human fetuses.

Normal fetal ranges for red cell glycolytic intermediates at 18-24 weeks gestation, which are useful as reference values for the prenatal diagnosis of erythroenzymopathies, were established for the first time. Characteristic increases in glucose-6-phosphate (G6P), fructose-6-phosphate (F6P) and particularly fructose-1,6-diphosphate (FDP) suggest that there is no metabolic block at the phosphofructokinase (PFK) step of glycolysis as previously suggested by others for premature infants on the first day of life. Neither reticulocytosis nor anaemia consistently led to further increases in the early metabolites as occurs in adults. However, very large increases in G6P, F6P and particularly FDP may occur independently of anaemia and reticulocytosis. This suggests that activation of hexokinase (HK) and/or PFK can take place as in adults but the stimulus is probably different to adults. The 2,3-DPG in normal fetuses is higher than in adults and increases still further in anaemic fetuses with or without transfusion of adult blood. The pattern of intermediates found in the fetus suggests that the controlling mechanism for the increased 2,3-DPG may be an in vivo relative preponderance of PFK activity over that of pyruvate kinase (PK) rather than regulation of HK as proposed for adult subjects with anaemia or high altitude hypoxia.

Red cell glycolytic intermediates and adenosine triphosphate in preterm infants on the first day of life.

Red cell glycolytic intermediates and ATP were evaluated in 47 appropriate for gestational age preterm infants on the 1st day of life who were divided into three groups on the basis of gestational age: 28-30, 31-33, and 34-36 wk. The results were compared to those previously obtained in term infants. The concentrations of glucose-6-phosphate, total triose phosphates, and ATP were significantly higher than in term infants but appeared to be appropriately elevated for the young mean age of the red cell population. The concentration of red cell 2,3-diphosphoglycerate (2,3-DPG) was significantly decreased when compared to term infants and was lowest at 28-30 wk gestation. The content of red cell 3-phosphoglycerate was increased in term infants and was inappropriately elevated for the age of the red cell population at 28-30 wk gestation. This pattern of glycolytic intermediates was suggestive of a young red cell population metabolizing at an increased glycolytic rate with increased flow through the phosphoglycerate kinase step rather than the 2,3-DPG bypass in "normal" preterm infants. Two preterm infants of 28-30 wk gestation with low red cell intracellular pH were also evaluated and had markedly decreased concentrations of red cell 2,3-DPG and ATP and all phosphorylated intermediates distal to the phosphofructokinase reaction, indicative of a cross-over at the phosphofructokinase step secondary to acidosis.(ABSTRACT TRUNCATED AT 250 WORDS)

Genetic components of variations of red cell glycolytic intermediates at two altitudes among the South American Aymara.

Red cell haemoglobin (Hb), haematocrit (Ht), 2,3-diphosphoglycerate (DPG), and adenosine triphosphate (ATP) levels were measured in 876 individuals from six villages at two altitude levels (altiplano and coast) of the Departmento de Arica of Northern Chile. Of these, data on 761 individuals are subjected to analysis to search for the evidence of genetic adaptation to a hypoxic environment at a high altitude. Total phenotypic variance for each of the variables is higher at the altiplano as compared to their counterparts at the coastal level. Data on 1127 pairs of relatives of six degrees of relationships are used to determine the genetic component of variation in each of these four traits. To a certain extent the larger familial correlations as well as higher variances at altiplano are explained by the apparent assortative mating (which may again be due to their restricted population size) at the higher elevation. Yet, at least in three variables (Hb, Ht, and DPG) no reduction in the additive genetic component of variation is noticed at the higher altitude. ATP seems to have the highest degree of genetic component of variance, particularly at the coastal level. Some implications of these results are discussed in the light of their roles in the glycolytic pathway.

Red cell metabolic alterations in postnatal life in term infants: possible control mechanisms.

Red cell glycolytic intermediates and enzymes in term infants in the first year of life were correlated with the fetal hemoglobin concentration (%F), intra- and extracellular venous pH, plasma inorganic phosphorus (Pi) and pyruvate kinase (PK) activity. Changes in the non-age-dependent enzymes phosphoglycerate kinase, enolase, and phosphofructokinase correlated most significantly with the postnatal decline in %F (P less than 0.001), not the age of the red cell population, as reflected in PK activity. The age-dependent enzymes, hexokinase and glucose-6-phosphate dehydrogenase, however, correlated well with PK activity (P less than 0.001). The concentration of glucose-6-phosphate did not correlate significantly with the postnatal decline in %F (P greater than 0.05) or PK (P greater than 0.10), but correalted significantly with the plasma Pi concentration (P less than 0.001). "Total triose phosphate" and 2,3-diphosphoglycerate did not correlate with Pi. It appears from these studies that an extracellular factor, Pi alters the pattern of glycolytic intermediates in term infants and that the postnatal changes in phosphoglycerate kinase, enolase, and phosphofructokinase are unique to the "fetal" red cell and reflect passage from fetal to "adult" erythropoiesis.

A path analysis of the causal relationships between red cell glycolytic intermediates, ADP and ATP in sickle cell anemia

The statistical relationships among the glycolytic intermediates (GIs) of the Embden-Meyerhof pathway, adenine nucleotides (ANs) and various hematological measures were estimated for 34 sickle cell anemia patients. Heterogeneity in linear and quadratic regressions of hemoglobin and hematocrit, both singly and jointly, on the GI and AN variables implied 1) that any single formula to standardize optical density measures of the GIs and ANs on a per gram hemoglobin or per liter cell water basis would not uniformly remove hemoglobin and hematocrit effects; 2) that ignoring significant hematological effects could bias the estimates of correlation among GIs and ANs; and 3) that hemoglobin and hematocrit measures do not reflect the same source of variability. The correlations among the GIs and ANs, after adjustment for hematological variability, were analyzed by path analysis to determine which of five proposed path models for cause and effect relationships were compatible with the data. AMP had a greater influence on ADP (coefficient of determination (CD) = 23%) than all the GIs together, while G6P and ADP influenced ATP variability the most (CD = 33% and 12%). The contributions of unknown factors to ADP and ATP variability were large for all models (CD = 56–77%) possibly due to stress of sickle cell disease. The path model with AMP and the four GIs (G6P, F6P, FDP, DHAP) influencing ADP variation, and the same GIs and ADP influencing ATP was the model most compatible with the data.

The effect of epinephrine on the in vivo concentration of erythrocyte glycolytic intermediates.

SummaryErythrocyte adenosine triphos-phate (ATP) concentration was found to increase in adult rhesus monkeys which have been injected with 3.5 mg of epinephrine. The average increase in red cell ATP concentration was 19.5% (significant at the 1% probability level). Epinephrine injection also increased the concentration of the early red cell glycolytic intermediates, glucose 6-phosphate (G6P), fructose 6-phos-phate (F6P), and dihydroxyacetone phosphate (DHAP). Respiratory alkalosis, which might have been induced by the epinephrine, is not responsible for the glycolytic changes. This effect of epinephrine on rhesus red cell glycolysis is compatible with an in vivo stimulation of red cell hexokinase by epinephrine or some substance elicited by epinephrine and suggests the possibility that such a stimulation may have a physiologic role in the mammalian erythrocyte.The authors wish to thank John A. Faulkner and Daniel H. Ringler for their help in the experiments involving the injection of monkeys with epinephr...

Abnormal Red Cell Metabolism in Patients With Chronic Uremia: Nature of the Defect and Its Persistence Despite Adequate Hemodialysis

A red cell metabolic abnormality, which diminishes the maximum activity of the pentose phosphate shunt, occurs in some uremic patients, even those adequately dialyzed with fluids prepared from distilled or charcoal-filtered water. Within individual patients the severity of this abnormality does not change even after 9 mo of consecutive hemodialyses. However, between patients it does correlate inversely with hematocrit. When erythrocytes from patients with the abnormality are stressed with oxidant compounds, such as ascorbate, erythrocyte glucose consumption and lactate formation are abnormally increased, while lactate/pyruvate ratios abnormally diminish. Concomitantly, red cell glycolytic intermediates, including fructose-1,6-diphosphate, glyceraldehyde-3-phosphate, 3-phosphoglycerate, phosphoenol pyruvate, and pyruvate, markedly accumulate. Surprisingly, no increase of 2-phosphoglycerate occurs, which suggests that inefficient phosphoglyceromutase activity underlies this perturbation of erythrocyte metabolism and its associated hemolytic process.

Abnormal red cell metabolism in patients with chronic uremia: Nature of the defect and its persistence despite adequate hemodialysis

A red cell metabolic abnormality, which diminishes the maximum activity of the pentose phosphate shunt, occurs in some uremic patients, even those adequately dialyzed with fluids prepared from distilled or charcoal-filtered water. Within individual patients the severity of this abnormality does not change even after 9 mo of consecutive hemodialyses. However, between patients it does correlate inversely with hematocrit. When erythrocytes from patients with the abnormality are stressed with oxidant compounds, such as ascorbate, erythrocyte glucose consumption and lactate formation are abnormally increased, while lactate/pyruvate ratios abnormally diminish. Concomitantly, red cell glycolytic intermediates, including fructose-1,6-diphosphate, glyceraldehyde-3-phosphate, 3-phosphoglycerate, phosphoenol pyruvate, and pyruvate, markedly accumulate. Surprisingly, no increase of 2- phosphoglycerate occurs, which suggests that inefficient phosphoglyceromutase activity underlies this perturbation of erythrocyte metabolism and its associated hemolytic process.

Red cell metabolic changes in acute and chronic exposure to high altitude.

The red blood cell has occupied a central position in studies of how man adapts to high altitudes. With the discovery that the level of DPG has important implications for erythrocyte oxygen affinity, the study of red cell metabolism at high altitudes has taken on new and greater significance. Change in the level of DPG is most certainly related to changes in the levels of other red cell glycolytic intermediates. The appropriate next steps in understanding the mechanism of the increase in DPG are to ascertain which of the enzymes of glycolysis are activated by altitude exposure, and to identify the stimuli which are operating on this enzyme or enzymes. We initiated this next step with studies in Leadville, Colorado, elevation 10,200 feet.

RED CELL METABOLISM IN THE NEWBORN INFANT. V. GLYCOLYTIC INTERMEDIATES AND GLYCOLYTIC ENZYMES

Previous studies demonstrated that the erythrocytes of the newborn infant have a relative phosphofructokinase deficiency and inappropriate glucose consumption for cell age. In view of these findings, an analysis of red cell glycolytic intermediates and all Embden-Meyerhof pathway enzyme activities was made in the red cells of infants, normal adults, and subjects with reticulocytosis to define further differences in metabolism and search for evidence of a metabolic blockade. The erythrocytes of subjects with reticulocytosis were found to possess increased quantities of glucose-6-phosphate, fructose-6-phosphate and 2,3-diphosphoglycerate. The elevation of the hexose phosphates was even greater in the red cells of the premature infants and was associated with a decrease in levels of 2,3-diphosphoglycerate and phosphoenolpyruvate. Measurement of enzyme activities indicated that, in addition to the phosphofructokinase deficiency, the cells of the newborn infant have markedly increased activities of enolase and phosphoglycerate kinase. It is suggested that the increase in the level of the hexose phosphates in the erythrocytes of the infants and subjects with reticulocytosis is a reflection of this relative phosphofructokinase deficiency, with this deficiency being greater in newborn infants. The differences in the enzymatic profile between the erythrocytes of the newborn and those of the normal adult is not solely a function of their younger age. Some of the differences are a reflection of the presence of a cell unique to this period of life.