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Interplay between glutathione-S-transferase and glucose-6-phosphate dehydrogenase in neonatal cord blood.

Three hundred neonatal cord blood samples were collected from two major cities in Jordan and assayed for glutathione-S-transferase (GST), glutathione, and glucose-6-phosphate dehydrogenase (G6PD). A significant positive correlation between the levels of G6PD and GST activities was detected. When the G6PD activity decreased, the GST activity declined. A similar concurrent decrease in the concentration of reduced glutathione was also observed. When the samples were divided into males and female samples, some significant variations in the levels of the two enzymes were observed. Female samples exhibited higher G6PD and GST activities as compared with male samples. Moreover, the incidence of severe and moderate G6PD deficiencies was higher in male as compared with female samples. Analyses of the samples for total bilirubin, red blood cells, hematocrit, and hemoglobin were also performed, and slight nonsignificant variations were noted.

Bilirubin↗

The potential use of xylitol in glucose-6-phosphate dehydrogenase deficiency anemia.

NADP-linked xylitol dehydrogenase has been found to be present in human red blood cells. This enzyme activity is normal in most glucose-6-phosphate dehydrogenase (G6PD)-deficient red cells. Xylitol was explored as a potential agent for treatment of hemolysis in patients with G6PD-deficiency. Intracellular GSH (glutathione, reduced) was first converted to its oxidized form by incubation of the erythrocytes with acetylphenylhydrazine or by pretreatment with methyl phenyldiazenecarboxylate. The addition of 0.15 M xylitol was shown to be more effective than 0.15 M glucose in maintaining the levels of GSH in G6PD-deficient red cells during such oxidative challenge. Rabbit erythrocytes contain less activity of G6PD and glutathione reductase compared with the normal human adult values, but have an active xylitol dehydrogenase. The rabbit erythrocyte is sensitive to acetylphenylhydrazine and primaquine phosphate. In both in vivo and in vitro experiments, xylitol was found to partially prevent acetylphenylhydrazine induced acute hemolysis of the rabbit red cell and GSH content was found to be preserved. The intravenous injection of xylitol (0.5 g/kg body weight per 6 hr) for 6 days, seemed to be nontoxic to the animal. The results suggest that xylitol should be further investigated as an agent for the treatment of G6PD-deficient patients during acute hemolytic episodes.

Alcohol Oxidoreductases↗

Oxidant injury of caucasian glucose-6-phosphate dehydrogenase-deficient red blood cells by phagocytosing leukocytes during infection.

Patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency of red blood cells (RBC) may develop sudden hemolytic anemia during infection. Since phagocytizing polymorphonuclear leukocytes (PMN) are known to generate hydrogen peroxide, we explored the influence of this oxidant product of PMN on juxtaposed G6PD-deficient and normal RBC. The oxidant stress induced by phagocytosis depleted G6PD-deficient RBC of reduced glutathione (GSH) and this was associated with rapid removal of these cells from the circulation by the liver and spleen. No such effect was observed on normal RBC. Phagocytizing chronic granulomatous disease (CGD) PMN which lack hydrogen peroxide generation, failed to diminish GSH level in G6PD-deficient RBC. Thus, PMN can pose as a source of oxidant damage to G6PD-deficient RBC due to hydrogen peroxide generated during phagocytosis.

Anemia, Hemolytic↗

Control of glucose-6-phosphate dehydrogenase deficiency on the formation of mutagenic and carcinogenic metabolites derived from benzo(a)pyrene.

It has been observed that human lymphocytes (HL) and fibroblasts, isolated in vitro from donors carrying the Mediterranean variant of glucose-6-phosphate dehydrogenase (G6PD), show a great decrease in this enzymatic activity, the hexose monophosphate shunt, and the NADPH/NADP+ ratio. This effect is associated with a decreased sensitivity of G6PD-deficient cells to the benzo(a)pyrene (BaP) cytotoxic effect and to a decreased in vitro transformation of BaP-treated fibroblasts. Further, benzo(a)anthracene (BaA)-induced BaP hydroxylase activity is lower in G6PD-deficient cells, when measured in the presence of endogenous NADPH. It has been hypothesized that the NADPH level could be rate-limiting for the NADPH-dependent steps of BaP metabolic activation. To test this hypothesis, the formation of BaP metabolites was studied in normal and G6PD-deficient HL incubated with the carcinogen. HPLC profiles of organic-soluble metabolites revealed that both types of HL produced all the following known BaP metabolites: 9,10-, 4,5- and 7,8-dihydrodiols, quinones, 9- and 3-hydroxy and two peaks of more polar metabolites. There was a great decrease of the various metabolites in the deficient HL. A decrease of total water-soluble BaP metabolites also occurred. HL formed mutagenic metabolites for S. typhimurium TA100 (his-) when incubated with the rat liver S9 fraction. When intact HL substituted S9 fraction, a significant reversed mutation occurred only with normal HL. This could indicate that the NADPH pool is inadequate in G6PD-deficient HL for active BaP metabolism. Accordingly, deficient HL formed lower amounts of BaP:DNA adducts than control during incubation with BaP.

Benzo(a)pyrene↗

Apparent hemolysis in an AIDS patient receiving trimethoprim/sulfamethoxazole: case report and literature review.

OBJECTIVE: To describe a case of acute hemolysis associated temporally with administration of trimethoprim/sulfamethoxazole (TMP/SMX) in a patient with AIDS, review the available literature on TMP/SMX-induced hemolytic anemia, and discuss possible drug- and disease-related factors that may have contributed to the episode of hemolysis. CASE SUMMARY: A precipitous decrease in red blood cell count, hemoglobin, and hematocrit occurred shortly after a black woman with AIDS received a single intravenous dose of TMP/SMX for Pneumocystis carinii pneumonia. Following drug discontinuation and repeated transfusions, the patient's hematologic indices returned to baseline. LITERATURE SOURCES: References were obtained using MEDLINE searches, the bibliographies of articles identified during the searches, review articles, and standard textbooks. DATA SYNTHESIS: Of the two different mechanisms of TMP/SMX-induced hemolytic anemia, the reaction is most likely to occur via dose-related oxidative disruption of the erythrocyte membrane in subpopulations deficient in glucose-6-phosphate dehydrogenase (G6PD) activity. In the US, G6PD deficiency most frequently is encountered among blacks. The potential for hemolysis may be further increased in G6PD-deficient AIDS patients, who also appear to lack adequate intracellular glutathione, which is essential for protecting the erythrocyte membrane from oxidative damage. Although an assay for G6PD activity was not conducted, the case circumstances were consistent with TMP/SMX-induced hemolysis in a G6PD-deficient patient. CONCLUSIONS: Black patients with AIDS who are receiving relatively high (greater than or equal to 50 mg/kg/d) dosages of TMP/SMX should be monitored closely for signs and symptoms of hemolytic anemia.

AIDS-Related Opportunistic Infections↗

Rapid screening for glucose-6-phosphate dehydrogenase deficiency and haemoglobin polymorphisms in Africa by a simple high-throughput SSOP-ELISA method.

BACKGROUND: Mutations in the haemoglobin beta-globin (HbB) and glucose-6-phosphate dehydrogenase (G6PD) genes cause widespread human genetic disorders such as sickle cell diseases and G6PD deficiency. In sub-Saharan Africa, a few predominant polymorphic variants of each gene account for a majority of these deficiencies. Examining at a larger scale the clinical importance of these independent genetic disorders, their possible association with malaria pathogenesis and innate resistance, and their relevance for antimalarial drug treatment, would be easier if an accurate screening method with limited costs was available. METHODS: A simple and rapid technique was developed to detect the most prominent single nucleotide polymorphisms (SNPs) in the HbB and G6PD genes. The method is able to detect the different haemoglobin polymorphisms A, S, C and E, as well as G6PD polymorphisms B, A and A- based on PCR-amplification followed by a hybridization step using sequence-specific oligonucleotide probes (SSOPs) specific for the SNP variants and quantified by ELISA. RESULTS: The SSOP-ELISA method was found to be specific, and compared well to the commonly used PCR-RFLP technique. Identical results were obtained in 98% (haemoglobin) and 95% (G6PD) of the tested 90 field samples from a high-transmission area in Tanzania, which were used to validate the new technique. CONCLUSION: The simplicity and accuracy of the new methodology makes it suitable for application in settings where resources are limited. It would serve as a valuable tool for research purposes by monitoring genotype frequencies in relation to disease epidemiology.

Anemia, Sickle Cell↗

Frequency of malaria and glucose-6-phosphate dehydrogenase deficiency in Tajikistan.

BACKGROUND: During the Soviet era, malaria was close to eradication in Tajikistan. Since the early 1990s, the disease has been on the rise and has become endemic in large areas of southern and western Tajikistan. The standard national treatment for Plasmodium vivax is based on primaquine. This entails the risk of severe haemolysis for patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. Seasonal and geographical distribution patterns as well as G6PD deficiency frequency were analysed with a view to improve understanding of the current malaria situation in Tajikistan. METHODS: Spatial and seasonal distribution was analysed, applying a risk model that included key environmental factors such as temperature and the availability of mosquito breeding sites. The frequency of G6PD deficiency was studied at the health service level, including a cross-sectional sample of 382 adult men. RESULTS: Analysis revealed high rates of malaria transmission in most districts of the southern province of Khatlon, as well as in some zones in the northern province of Sughd. Three categories of risk areas were identified: (i) zones at relatively high malaria risk with high current incidence rates, where malaria control and prevention measures should be taken at all stages of the transmission cycle; (ii) zones at relatively high malaria risk with low current incidence rates, where malaria prevention measures are recommended; and (iii) zones at intermediate or low malaria risk with low current incidence rates where no particular measures appear necessary. The average prevalence of G6PD deficiency was 2.1% with apparent differences between ethnic groups and geographical regions. CONCLUSION: The study clearly indicates that malaria is a serious health issue in specific regions of Tajikistan. Transmission is mainly determined by temperature. Consequently, locations at lower altitude are more malaria-prone. G6PD deficiency frequency is too moderate to require fundamental changes in standard national treatment of cases of P. vivax.

Adult↗

Dynamic simulation of red blood cell metabolism and its application to the analysis of a pathological condition.

BACKGROUND: Cell simulation, which aims to predict the complex and dynamic behavior of living cells, is becoming a valuable tool. In silico models of human red blood cell (RBC) metabolism have been developed by several laboratories. An RBC model using the E-Cell simulation system has been developed. This prototype model consists of three major metabolic pathways, namely, the glycolytic pathway, the pentose phosphate pathway and the nucleotide metabolic pathway. Like the previous model by Joshi and Palsson, it also models physical effects such as osmotic balance. This model was used here to reconstruct the pathology arising from hereditary glucose-6-phosphate dehydrogenase (G6PD) deficiency, which is the most common deficiency in human RBC. RESULTS: Since the prototype model could not reproduce the state of G6PD deficiency, the model was modified to include a pathway for de novo glutathione synthesis and a glutathione disulfide (GSSG) export system. The de novo glutathione (GSH) synthesis pathway was found to compensate partially for the lowered GSH concentrations resulting from G6PD deficiency, with the result that GSSG could be maintained at a very low concentration due to the active export system. CONCLUSION: The results of the simulation were consistent with the estimated situation of real G6PD-deficient cells. These results suggest that the de novo glutathione synthesis pathway and the GSSG export system play an important role in alleviating the consequences of G6PD deficiency.

Computer Simulation↗

Red blood cell disorders in Rwandese neonates: screening for sickle cell disease and glucose-6-phosphate dehydrogenase deficiency.

OBJECTIVES: To determine the prevalence of haemoglobin (Hb) variants and glucose-6-phosphate dehydrogenase (G6PD) deficiency in Rwanda. METHODS: During a two-month period in 2005, 987 cord blood samples were obtained in two hospitals in Kigali and Butare, Rwanda. Screening for sickle cell disorders, other Hb disorders, G6PD deficiency and other rare erythroenzymopathy deficiencies was done using isoelectric focusing techniques and quantitative kinetic assays, respectively. RESULTS: The prevalence of Hb S trait was 2.7% and that of G6PD deficiency was 3.8%. No neonate suffered from a sickle cell disease (homozygous for Hb S or compound heterozygous for Hb S), from another clinically significant haemoglobinopathy, or from pyruvate kinase or glucose phosphate isomerase deficiency. CONCLUSIONS: Sickle cell disorders should be considered a public health problem in Kigali and Butare. A systematic neonatal screening programme for those disorders, and to diagnose G6PD deficiency, seems reasonable, but local health priorities must be considered. Adapted management of hereditary sickle cell and G6PD disorders should be available.

Anemia, Sickle Cell↗

Enhancement of riboflavin-mediated photo-oxidation of glucose 6-phosphate dehydrogenase by urocanic acid.

We have investigated the riboflavin (RF)-sensitized inactivation of glucose 6-phosphate dehydrogenase (G6PD) in the presence and absence of trans-urocanic acid (UCA). The inactivation of the enzyme results from its direct oxidation by the excited triplet RF in a Type-I-photosensitized reaction whose efficiency increases at low oxygen concentration. The addition of histidine to the system produced no change in the inactivation rate, discarding the participation of singlet oxygen in the reaction. On the other hand, the presence of UCA results in its bleaching, with a significant enhancement of RF-mediated inactivation of G6PD. Both the consumption of UCA and G6PD are faster at low oxygen concentrations. UCA also produced a decrease in the sensitizer photodecomposition yield. These results indicate that the enhancement of the RF-mediated G6PD inactivation observed in the presence of UCA is not a singlet oxygen-mediated process. It is proposed that UCA consumption and its effect on G6PD inactivation are due to a complex reaction sequence initiated by a direct oxidation of UCA by the excited sensitizer triplet. The oxidation of the semireduced flavin gives rise to reactive oxygen species (ROS) responsible for the increased rate of the process. This is supported by the protection afforded by several additives with ROS removal capacity: benzoate, superoxide dismutase and catalase.

Glucosephosphate Dehydrogenase↗

Extraction and characterization of a cytochemically assayable Na+/K+-ATPase inhibitor/glucose-6-phosphate dehydrogenase stimulator in the hypothalamus and plasma of man and the rat.

Some physicochemical properties of partially purified hypothalamic material from the spontaneously hypertensive rat, and of plasma from man and the rat, have been characterized using a validated cytochemical bioassay which measures the ability of biological fluids to stimulate fresh guinea-pig kidney glucose-6-phosphate dehydrogenase (G6PD) after 2 min of exposure to the test substance, as an indication of their ability to inhibit Na+/K+ adenosine triphosphatase (Na+/K+-ATPase) after 4-6 min of exposure. The G6PD-stimulating activity of both hypothalamic extract and plasma is soluble in water and insoluble in chloroform. During electrophoresis the activity from both sites appears in the same fractions and travels considerably further than lysine. After high-pressure liquid chromatography the activity of hypothalamic extract appears in a discreet fraction which does not absorb u.v. light. The activity of both the hypothalamic extract and plasma survives boiling and acid hydrolysis, but is substantially inhibited by prior incubation with digoxin antibody. From ultrafiltration studies, the substance responsible for the ability to stimulate G6PD appears to have a molecular weight of less than 500. The G6PD-stimulating activity of hypothalamic extracts was destroyed by ashing and by base hydrolysis. The ability of plasma of high activity to stimulate G6PD is considerably increased by incubating at 37 degrees C for 15 min and destroyed by incubation for 45 min. It is concluded that these and several other previously noted similarities suggest that the cytochemically assayable Na+/K+-ATPase-inhibiting/G6PD-stimulating activity in the plasma and hypothalamus may be due to the same ouabain-like substance.

Animals↗

Increase in glucose-6-phosphate dehydrogenase in adipocytes stimulates oxidative stress and inflammatory signals.

In adipocytes, oxidative stress and chronic inflammation are closely associated with metabolic disorders, including insulin resistance, obesity, cardiovascular disease, and type 2 diabetes. However, the molecular mechanisms underlying these metabolic disorders have not been thoroughly elucidated. In this report, we demonstrate that overexpression of glucose-6-phosphate dehydrogenase (G6PD) in adipocytes stimulates oxidative stress and inflammatory responses, thus affecting the neighboring macrophages. Adipogenic G6PD overexpression promotes the expression of pro-oxidative enzymes, including inducible nitric oxide synthase and NADPH oxidase, and the activation of nuclear factor-kappaB (NF-kappaB) signaling, which eventually leads to the dysregulation of adipocytokines and inflammatory signals. Furthermore, secretory factors from G6PD-overexpressing adipocytes stimulate macrophages to express more proinflammatory cytokines and to be recruited to the adipocytes; this would cause chronic inflammatory conditions in the adipose tissue of obesity. These effects of G6PD overexpression in adipocytes were abolished by pretreatment with NF-kappaB inhibitors or antioxidant drugs. Thus, we propose that a high level of G6PD in adipocytes may mediate the onset of metabolic disorders in obesity by increasing the oxidative stress and inflammatory signals.

3T3 Cells↗

A contradiction between in vivo and in vitro activities of normal and variant glucose 6-phosphate dehydrogenase.

The presumed "physiologic activity" of normal glucose 6-phosphate dehydrogenase (G6PD), i.e. activity assayed in the presence of physiologic concentrations of ATP, 2,3-diphosphoglycerate, glucose 6-phosphate, NADP and NADPH in the normal red cells, is comparable to shunt pathway activity of intact normal red cells. In contrast, the presumed "physiologic activity" of G6PD variants associated with enzyme deficiency (Gd A- and Gd Mediterranean) is one order of magnitude higher than actual shunt pathway activity of the variant red cells. The difference of kinetic parameters of the enzyme in artificial buffer media and presumed physiologic medium in red cells cannot explain the discrepancy. The apparent discrepancy could be attributed either to (a) over-estimation of NADP and under-estimation of NADPH concentrations in the G6PD deficient red cells due to rapid oxidation of NADPH to NADP in preparation of hemolysate, or to (b) a large portion of NADP which accumulated in the G6PD deficient red cells binds with cellular components of intact red cells and is not available as substrate for G6PD.

Erythrocytes↗

Test for fused-cell origin of tumors with Mus caroli carrying glucose-6-phosphate dehydrogenase cellular mosaicism.

A test system for examining the fused cell-origin of tumors was developed by application of Mus caroli carrying the X-chromosome inactivation cellular mosaicism for G6PD. A G6PD heterodimer pattern is expected if a tumor is initiated from a fused cell. Among tumors induced by subcutaneous injection of a high dose of MCA, three tumors exhibited a single G6PD phenotype and one tumor exhibited a multiple G6PD phenotype; however, the G6PD heterodimer pattern was not found. Although the results obtained were not conclusive, this system is thought to be useful for detecting a possible fused cell-origin of tumors.

Animals↗

Glucose-6-phosphate dehydrogenase in rat lung alveolar epithelial cells. An ultrastructural enzyme-cytochemical study.

Glucose-6-phosphate dehydrogenase (G6PD) is the key enzyme of the pentose phosphate pathway in carbohydrate metabolism, and it plays an important role in cell proliferation and antioxidant regulation within cells in various organs. Although marked cell proliferation and oxidant/antioxidant metabolism occur in lung alveolar epithelial cells, definite data has been lacking as to whether cytochemically detectable G6PD is present in alveolar epithelial cells. The distribution pattern of G6PD within these cells, if it is present, is also unknown. The purpose of the present study was to investigate the subcellular localization of G6PD in alveolar cells in the rat lung using a newly-developed enzyme-cytochemistry (copper-ferrocyanide) method. Type I cells and stromal endothelia and fibroblasts showed no activities. Electron-dense precipitates indicating G6PD activity were clearly visible in the cytoplasm and on the cytosolic side of the endoplasmic reticulum of type II alveolar epithelial cells. The cytochemical controls ensured specific detection of enzyme activity. This enzyme may play a role in airway defense by delivering substances for cell proliferation and antioxidant forces, thus maintaining the airway architecture.

Animals↗

A diagnostic kit to screen individuals with glucose-6-phosphate dehydrogenase defect and its application on anti-malaria spot in the countryside.

OBJECTIVE: To prepare a kit for screening individuals with glucose-6-phosphate dehydrogenase (G6PD) defect. The kit is easy to use and to get the fast as well as reliable results. Especially it is suitable for the anti-malaria spots usually located in the remote countryside where no electricity is available. METHODS: The double filter paper method and other 2 techniques, the quantitative method and the single filter paper method, were used to determine G6PD activity in 70 samples of human erythrocytes. It was found that the results of the double filter paper method and those of the single filter paper method in the first 8 hours after the drying of the blood-soaked filter paper were consistent with those of the quantitative method. When a piece of blood-soaked paper is left under room temperature more than 24 hours, G6PD in the erythrocytes deteriorated spontaneously and consequently the number of positive cases increased along with the elapse of time. RESULTS: Satisfactory results were achieved when the kit was used to screen cases of G6PD defect from 151 farmers who were receiving anti-malaria therapy. The kit was made according to a technique named "double filter paper" method. CONCLUSIONS: These findings suggest that the double filter paper method can reveal the level of G6PD activity and the results are rapidly obtained when the method is used on the anti-malaria spot.

Anemia, Hemolytic↗

[Study on G487A mutation of the glucose-6-phosphate dehydrogenase gene].

OBJECTIVE: In order to reveal the molecular evolution and ethnic origin and immigration, on the basis of G6PD G487A mutation, and estimate the incidence of the mutation in Bai, Dai, and Han people in Yunnan and Guangxi. METHOD: G6PD deficient individuals were studied by using PCR-RE, PCR-SSCP and DNA sequencing. RESULTS: The G487A mutation in Bai and Dai people was identified for the first time and its relative incidences were 6/66 and 1/52, respectively. The individuals of G6PD G487A mutation showed the features of G6PD clinic type III. No G487A was found in Han people in Guangxi(0/46). CONCLUSION: The G6PD G487A mutation revealed in some ethnic groups of China implies that different national minorities of Chinese may be origined from a common ancestor.

Asian People↗

Effect of primaquine standard dose (15 mg/day for 14 days) in the treatment of vivax malaria patients in Thailand.

Primaquine (8-aminoquinoline), the only effective drug to prevent relapses of the persistent liver forms of Plasmodium vivax and Plasmodium ovale, can induce hemolytic anemia in patients with glucose-6-phosphate dehydrogenase (G6PD) deficiency. The severity varies considerably among affected individuals. Three hundred and sixty-four Plasmodium vivax cases (342 G6PD-normal and 22 G6PD-deficient) were given a 3-day course of chloroquine (total dose 1,500 mg) followed by primaquine 15 mg a day for 14 days and completed a 28-day follow-up. All G6PD-deficient patients were male; there were no relapses or serious adverse events during the study. Although a significant decrease in hematocrit levels and an increase in the percent reduction of hematocrit levels were observed on day 7 (34.9+/-5.0 vs 26.7+/-5.4; (-1.2)+/-14.4 vs (-24.5) +/-13.9 respectively) and on day 14 (35.7+/-4.3 vs 30.9+/-3.1; 1.6+/-17.8 vs (-11.0) +/-19.3 respectively) blood transfusion was not required. Daily doses of 15 mg of primaquine for 14 days following a full course of chloroquine when prescribed to Thai G6PD deficient patients where Mahidol variant is predominant, are relatively safe.

Adult↗