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Occupational exposure to lead and blood cholesterol in glucose-6-phosphate dehydrogenase deficient and normal subjects.

The effect of chronic lead poisoning on blood cholesterol levels of 148 patients, admitted to the Institute of Occupational Medicine of the University of Cagliari (Italy), was studied in connection with the genetic pattern of Glucose-6-Phosphate Dehydrogenase (G6PD) activity. The erythrocyte G6PD activity of twenty-six patients was genetically deficient. Multiple regressions were elaborated including the following in the model as independent variables: age, Quetelet index and blood lead or urinary lead in the 24 hours following 15 mg/Kg of i.v. calcium ethylen-diamine-tetracetate (EDTA) (PbUEDTA), expressed as a ratio with body weight (PbUEDTA/Kg). Dependent variables were alternatively, total cholesterol, cholesterol esters, LDL and HDL cholesterol. The analysis showed that G6PD deficient subjects have generally lower intercepts, but only for HDL the difference approached the statistical significance. Lead poisoning affected blood cholesterol of G6PD deficient subjects differently from normal ones: while total cholesterol and LDL tended to decrease in both, positive slopes were observed for cholesterol esters in G6PD deficient and for HDL in G6PD normal subjects.

Adult↗

Glucose-6-phosphate dehydrogenase from Plasmodium berghei: kinetic and electrophoretic characterization.

Evidence is given for the existence of a parasite-specific glucose-6-phosphate dehydrogenase in Plasmodium berghei by characterization of its kinetic and electrophoretic properties. After separating the parasites from infected RBC the G6PD was purified by affinity chromatography with 2'5'-ADP-Sepharose 4B. In cellulose acetate electrophoresis malarial G6PD significantly differs from the red cell enzyme. The subunits of the parasite-specific G6PD have a molecular weight of 55 kD in contrast to 59 kD of the RBC enzyme. G6PD from P. berghei shows no cross-reactivity with antibodies against G6PD from rat erythrocytes. The Km-value for G6P of malarial G6PD is increased by one order of magnitude compared with the host cell enzyme.

Animals↗

Frequency of glucose-6-phosphate dehydrogenase variants and deficiency in Arabia.

Several variants of G6PD were found in different regions of Saudi Arabia. The variants were separated on the basis of their electrophoretic mobility and activity towards glucose-6-phosphate. G6PD*B was the most common enzyme found in all regions investigated. Variants included G6PD*A, G6PD*A-, G6PD*B weak and G6PD*def. The frequency of the variants shows significant differences among the regions of Saudi Arabia examined.

Cross-Sectional Studies↗

Glucose-6-phosphate dehydrogenase deficiency among three national minorities in Hainan Island, China.

A total of 296 healthy males belonging to three national minority groups, Li, Miao and Hui, in Hainan Island, China, were screened for G6PD deficiency. 9 out of 139 Li (6.47%), 8 out of 48 Miao (16.67%), and 2 out of 109 Hui (1.83%) individuals were found to be G6PD deficient. Of these 19 variant samples, three were subjected to G6PD characterization and found to be different from each other. They were considered to be G6PD Miaozu-Baisha, G6PD Qingyuan, and a new variant tentatively named G6PD Huizu-Sanya.

Asian People↗

Changes in oxidative activities of chondrocytes during the early development of natural murine osteoarthritis.

A high incidence of natural osteoarthritis of the knee joint is found in male mice of the STR/ORT strain. The condition affects mainly the medial tibial cartilage and by the age of 27 weeks most male mice of this strain show some osteoarthritic change. Analysis of the oxidative metabolism of the chondrocytes during the development of the lesion has been facilitated by the techniques of quantitative cytochemistry. The activity of glucose-6-phosphate dehydrogenase (G6PD) has been investigated as indicative of the NADPH-generating pentose-phosphate pathway; the activities of glyceraldehyde-3-phosphate (G3PD) and lactate dehydrogenase (LDH) have been studied as indicators of glycolytic activity. In young STR/ORT mice the G6PD activity of the lateral tibial cartilage was greater and more variable than in the control mice of the CBA/HT6 strain. The activity in the medial cartilage, relative to that in the lateral cartilage, decreased with age; this change was not reflected in the activities of the other enzymes. In the lateral cartilage, the expected relationship was found between the G6PD and the G3PD activities and between the LDH and the G3PD activities. In the medial cartilage, the G6PD activities were not related to the G3PD activities. The decreased proportionality of the G6PD activities in the medial cartilage as against that in the lateral cartilage was detected in mice as young as 9 weeks; by 27 weeks of age nine of the 13 mice showed marked depression of medial as against lateral G6PD activities. In contrast, only four of the 13 mice showed any overt histological charge until up to the age of 28 weeks.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

Heterogeneity of glucose-6-phosphate dehydrogenase enzymopathies in the GDR.

G6PD variants of 13 patients from 12 German families with different clinical symptoms have been characterized kinetically. Vmax G6PD was nearly zero in red blood cells of all carriers. Therefore G6PD variants were isolated from leucocytes, which proved to be a suitable source for analysis of instable G6PD variants. The testing program included KmG6P, KmNADP, Ki values of NADPH, ATP and 2,3 P2G, rate of utilization of dG6P, Gal6P, dNADP, NAD, and pH dependence. From the results obtained one can conclude that all analyzed G6PD variants represent individual mutations. The degree of metabolic dysregulation can be explained by the different kinetic and physico-chemical properties of these G6PD variants.

Erythrocytes↗

Mechanisms of decreased erythrocyte deformability and survival in glucose 6-phosphate dehydrogenase mutants.

We have studied the nature of the oxidative lesion of the erythrocyte membrane in glucose-6-phosphate dehydrogenase (G6PD) mutants with chronic hemolysis, comparing these membranes with those from normal red cells (RBC) subjected to oxidative stress in vitro. Disulfide-linked polypeptide aggregates are found in membranes from fresh RBC of these G6PD mutants and from aerobically incubated normal erythrocytes. As further evidence of oxidative damage, increased disulfide bonds were found in the RBC membranes from both the mutants and incubated normal RBC. The intermolecular bonds which cross-link membrane polypeptides to form the observed aggregates, however, only accounted for a fraction of the membrane disulfide bonds present. Thus, most of the disulfide bonds in the G6PD mutants were intramolecular. These intramolecular disulfide bonds were widely distributed on the membrane polypeptides, but were found to be concentrated on cytoskeletal anchoring proteins, bands 2.1-2.3, using [14C] iodoacetamide labelling of the sulfhydryls involved in disulfide bonds. The intermolecular bonds, on the other hand, were concentrated in spectrin. When G6PD mutant membranes were examined on sucrose density gradients, a subpopulation of dense membranes was observed which resembled the membranes of oxidatively stressed normal RBC both in increased density and in increased binding of nonhemoglobin cytoplasmic protein. To study the relationship between sulfhydryl oxidation, membrane density and RBC viscosity the sulfhydryl oxidant diamide (diazine dicarboxylic acid bis-[dimethylamide]) was used. Diamide treated erythrocytes, like the G6PD mutants, had decreased GSH, increased polypeptide aggregates, increased viscosity, but no change in ATP. We conclude that in G6PD mutants with chronic hemolysis oxidative damage includes aggregate formation due to intermolecular disulfide bonds, and intramolecular disulfide bond formation associated with increased binding of non-hemoglobin cytoplasmic proteins to the membrane. The relative importance of intermolecular and intramolecular disulfide bond formation and the mechanism whereby these changes may produce decreased RBC deformability and survival remain to be determined.

Anemia, Hemolytic↗

[The detection of the location of glucose-6-phosphate dehydrogenase in the fibroblasts of voles and mice and in rat myoblasts by using monoclonal antibodies against glucose-6-phosphate dehydrogenase].

Monoclonal antibodies (MAs) were produced against glucose-6-phosphate dehydrogenase (G6PD) of two vole species--Microtus arvalis and M. subarvalis. The binding level of the MAs to G6PD in both species were almost the same, which suggested that these MAs may be specific for the antigenic determinants common to G6PD of these species. The MAs produced against the vole G6PD were used for its intracellular localization. The patterns obtained after staining cells with the use of MAs against G6PD were the same as those obtained after staining with the use of antibodies against F-actin. There was a good conformity between the results of light and electron microscopic immunoenzyme analyses with regard to the binding of MAs produced to the actin microfilaments. It is concluded that G6PD is closely associated with actin microfilaments of the cell cytoskeleton.

Animals↗

Henna: a potential cause of oxidative hemolysis and neonatal hyperbilirubinemia.

OBJECTIVE: To evaluate the in vitro oxidation potential of lawsone (2-hydroxy-1,4 naphthoquinone). Lawsone is a chemical present in henna, the crushed leaves of which are used worldwide as a cosmetic agent to stain the hair, skin, and nails. METHODOLOGY: Venous blood from glucose-6-phosphate dehydrogenase (G6PD)-normal and G6PD A- subjects were incubated with various amounts of lawsone for 2 hours at 37 degrees C. Reduced glutathione and methemoglobin (MHb) levels were measured before and after incubation. RESULTS: Final molar concentrations of lawsone in normal blood of 1.4, 2.8, 5.7, and 8.6 x 10-3 mol/L increased MHb percentages from 0.5% to 2.2%, 8.3%, 9.5% and 12.5%, respectively. In a C6PD A- blood, MHb percentages were 19.8%, 32.2%, 44.9%, and 53.9%. At a lawsone concentration of 2.8 x 10-3 mol/L, blood from 15 healthy adults formed MHb percentages of 7.4% +/- 3.3% (+/- 1 SD); in blood from 4 G6PD A- adults, percentages were 44.5%, 40.6%, 41.3%, and 42.8%. Simultaneous measurements of reduced glutathione revealed preincubation values of greater than 40 mg/100 mL of red cells in blood of healthy and G6PD A- subjects. Postincubation values were greater than 40 in blood of healthy subjects and less than 40 in blood of G6PD A- subjects. CONCLUSIONS: These in vitro observations indicate that lawsone is an agent capable of causing oxidative hemolysis. In regions of the world where there is a high incidence of G6PD deficiency and unexplained hyperbilirubinemia, oxidative hemolysis secondary to the cutaneous application of henna could be the initiating event.

Adult↗

Mortality of lead smelter workers with the glucose-6-phosphate dehydrogenase-deficient phenotype.

The mortality experience of 1345 male workers in a lead and zinc smelting plant was followed from 1973 to 1991. Information on the erythrocyte glucose-6-phosphate dehydrogenase (G6PD) phenotype was available for 1,222 (90.9%) cohort members, which provided the opportunity to compare the mortality experience of G6PD-deficient subjects to wild-type-G6PD coworkers with similar exposure to lead. A significant decrease in mortality was observed among the total cohort as well as among the subcohort of production and maintenance workers. Most deaths (27 of 31) and all cancer deaths occurred among production and maintenance workers. Lung cancer mortality was lower than expected. Two deaths from stomach cancer were observed versus 0.6 expected. Mortality from all causes and cancer mortality were lower among production and maintenance workers with the G6PD-deficient phenotype compared to coworkers with the wild-type phenotype. Although the low statistical power of this study prevents conclusive inference, lead smelter workers with the G6PD-deficient phenotype did not suffer adverse health outcomes in terms of mortality from all causes and cancer mortality compared to coworkers with the wild-type G6PD.

Adult↗

Leukocyte glucose 6 phosphate dehydrogenase as prognostic indicator in ANLL and CML.

Glucose 6 phosphate dehydrogenase (G6PD) was estimated in the leucocytes of 35 patients with acute non-lymphocytic leukemia (ANLL) and 10 patients with chronic myeloid leukemia (CML). G6PD levels were found to be significantly decreased in majority of the patients with ANLL while it was increased in all CML patients. Variation in G6PD was found to be dependent on the percentage of myelocytes inANLL. Cytogenetic analysis was also carried out in these patients. Correlation analysis of leucocyte G6PD activity and karyotype with prognostic assessment clearly indicated the association of (s) high percentage of chromosomal abnormalities especially translocations, (b) low survival and remission rates, with patients having decreased G6PD activity when compared to patients with normal activity in ANLL. The studies indicate that leucocyte G6PD may be useful as a diagnostic and prognostic tool.

Biomarkers, Tumor↗

Mortality in a cohort of men expressing the glucose-6-phosphate dehydrogenase deficiency.

The objective of this study was to test the hypothesis of a lower mortality from cancer and cardiovascular diseases among men expressing glucose-6-phosphate dehydrogenase (G6PD) deficiency. We designed a mortality study based on death certificates from January 1, 1982 through December 31, 1992 in a cohort of G6PD-deficient men. Cohort members were 1,756 men, identified as expressing the G6PD-deficient phenotype during a 1981 population screening of the G6PD polymorphism. The setting was the island of Sardinia, Italy. Outcome measures were cause-specific standardized mortality ratios (SMRs), which were computed as 100 times the observed/expected ratio, with the general Sardinian male population as the reference. Deaths from all causes were significantly less than expected due to decreased SMRs for ischemic heart disease (SMR, 28; 95% confidence interval [CI], 10 to 62), cerebrovascular disease (SMR, 22; 95% CI, 6 to 55), and liver cirrhosis (SMR, 12; 95% CI, 0 to 66), which explained 95.6% of the deficit in total mortality. All cancer mortality was close to the expectation, with a significant increase in the SMR for non-Hodgkin's lymphoma (SMR, 545; 95% CI, 147 to 1,395). A decrease in mortality from cardiovascular diseases was one of the study hypotheses, based on an earlier human report and experimental evidence. However, selection bias is also a likely explanation. Further analytic studies are warranted to confirm whether subjects expressing the G6PD-deficient phenotype are protected against ischemic heart disease and cerebrovascular disease. This cohort study is consistent with more recent case-control studies in rejecting the hypothesis of a decreased cancer risk among G6PD-deficient subjects. The observed increase in mortality from non-Hodgkin's lymphoma and decrease in mortality from liver cirrhosis were not previously reported.

Adult↗

[Investigation of electrophoretical enzyme phänotypes glucose-6-phosphate dehydrogenase, red cell acid phosphatase, phosphoglucomutase and adenosine deaminase of permanent human cell lines (author's transl)].

Isoenzymes of 11 cell lines were investigated by electrophoretical separation. All lines have been cultivated from tissues of white persons, all but one (Leuc. Th. B.) were phosphoglucomutase 1 and all were adenosine deaminase 1. Three out of 11 cell lines did show glucose-6-phosphate dehydrogenase (G6PD) type B as expected. Two out of 8 cell lines with G6PD A were distinguishable by their specific type of "red cell" acid phosphatase (SEP). We conclude that in vitro the electrophoretical G6PD phänotyp B changed to phänotype A. Further 4 lines had other peculiarities which are indicative to their originality, though they were G6PD A. Our investigations did show that G6PD may become type A if a cell line changes to permanent growth capacity in vitro. The enzyme marker G6PD A alone may not be valuated as an absolute evidence for contamination or mix up with He-La Cells.

Acid Phosphatase↗

Frequency of glucose-6-phosphate dehydrogenase deficiency in some ethnic groups of Pakistan.

OBJECTIVE: To determine the frequency of G6PD deficiency in young healthy adult males of some ethnic groups in Pakistan. DESIGN: Descriptive study. PLACE AND DURATION OF STUDY: Study performed in Combined Military Hospital, Attock in collaboration with Armed Forces Institute of Pathology, Rawalpindi from October 2003 to January 2004. PATIENTS AND METHODS: Asymptomatic and healthy adult males were included in the study. A brief clinical record including age, ethnic group, place of residence, and history of past illnesses including fever, episodes of recurrent jaundice were recorded. Met-hemoglobin reduction test for G6PD screening was performed. Hemoglobin, red cell indices and total leukocyte count of G6PD deficient cases were measured on Sysmex KX 32 hematology analyzer. RESULTS: Three thousand adult males with age between 17 years to 23 years were screened. G6PD deficiency was detected in 1.8%. Deficiency state was 1.07% in Kashmiris, 1.47% in Punjabis, 2.77% in Sindhis, and 3.17% in Pathans. Past history of recurrent jaundice was present in 5.7%. Mild anemia was present in 3.8%. CONCLUSION: Frequency of G6PD deficiency was 1.8% in young healthy adults with insignificant difference among various ethnic groups except in Pathans.

Adolescent↗

Paternal transcripts for glucose-6-phosphate dehydrogenase and adenosine deaminase are first detectable in the human preimplantation embryo at the three- to four-cell stage.

The transition between dependence on maternal transcripts and proteins inherited in the oocyte and embryonic gene expression in the human preimplantation embryo occurs at the four- to eight-cell stage. Recently, studies using reverse transcriptase polymerase chain reaction (RT-PCR) have detected paternal transcripts for the Y-linked genes, ZFY and SRY, and the myotonic dystrophy associated protein kinase gene, DK, as early as the late pronucleate one-cell stage. However, expression at the protein level has not been demonstrated and its function at these early stages is unknown. Using coding sequence polymorphisms to distinguish maternal and paternal transcripts, we have examined the transcription of two ubiquitously expressed genes: X-linked glucose-6-phosphate dehydrogenase (G6PD) and adenosine deaminase (ADA). Both G6PD and ADA are housekeeping genes with TATA-less promoters which, because of their roles in metabolism and ubiquitous expression, may provide a more reliable indication of the timing of activation of the embryonic genome. They also each have biallelic polymorphisms with a high heterozygosity ratio which can be detected by restriction digestion. Couples undergoing in vitro fertilization (IVF) were screened for these polymorphisms. Individual spare oocytes and embryos at different stages of preimplantation development were analyzed by RT-PCR and appropriate restriction digestion in those cases in which the male partner carried a different allele to the female partner. In addition, since only female embryos inherit the paternal allele of X-linked G6PD, cDNA was also analyzed for ZFX/ZFY transcripts to identify the sex of each embryo. One hundred and twenty three individual oocytes and embryos were analyzed by RT-PCR and restriction digestion to detect the paternal transcripts from the polymorphic alleles. Maternal transcripts for G6PD, ADA, and ZFX were detected in all oocytes and embryos and at all stages. Following restriction digestion, paternal G6PD and ZFY transcripts were first detected at the four-cell stage and paternal ADA transcripts in an embryo at the three-cell stage coinciding with the onset of dependency on transcription from the embryonic genome. This approach should be widely applicable to other genes since similar polymorphisms exist in the coding regions of many genes.

Adenosine Deaminase↗

Characteristics of parathyroid hormone-specific cyclic changes of glucose-6-phosphate dehydrogenase activity in the distal convoluted tubule of the guinea pig.

The effect of parathyroid hormone (PTH) on the time course of glucose-6-phosphate dehydrogenase (G6PD) activity in the distal convoluted tubule of a vitamin D-depleted guinea pig was determined using quantitative cytochemistry. G6PD activity decreased to the stable basal level 5 hrs after the initiation of the kidney segment maintenance cultures. The exposure of the tissues to 1 pg/ml of bovine PTH-(1-84) induced a cyclic change of G6PD activity, whereas neither carboxyl-terminal PTH nor other hormones tested showed such activity. After a 16-min exposure to bovine PTH-(1-84), the peak height of each cycle began to decrease until it disappeared at 34 min. The second exposure to this hormone at 46 min reinduced a similar cyclic change with a similar peak, indicating full viability of the cells. When bovine PTH-(1-84) was incubated with an excess amount of anti-bovine PTH antibody, the PTH-induced G6PD activity was completely abolished. Throughout a 14-min exposure to either human PTH-(1-84), human PTH-(1-34) or bovine PTH-(1-84), similar cyclic changes were observed with the constant peak height regardless of the dose (10(-16)-10(-12) M), although the cycle length shortened progressively as the dose was increased. They were equipotent on a molar basis between the concentrations of 10(-16) and 10(-13) M at 6 min of hormone exposure. The present data demonstrate that the cytochemical bioassay of PTH in a vitamin D-depleted animal is based on a dose-dependent difference in the time course of G6PD activity.

Animals↗

Relationship of heat labile glucose-6-phosphate dehydrogenase and multiple molecular forms of the enzyme in senescent human fibroblasts.

Human fibroblasts derived from newborn foreskin and designated CF-3 were assayed for heat labile glucose-6-phosphate dehydrogenase (G6PD) when they had grown to confluency, as well as when they were arrested in an essentially nonmitotic state. Under both culture conditions there was an increase in heat labile G6PD (up to 25% of the total activity) as cells progressed through their in vitro lifespan; however, arrested cells exhibited less heat labile G6PD than did comparable growth controls (5-10% decrease). Acrylamide gel electrophoresis of crude G6PD preparations revealed three distinct bands of enzymatic activity. One of the bands was tentatively identified as the dimeric form of the enzyme and another as the tetrameric form. The tetrameric form was more heat sensitive, and the percent of the total activity of this form increased as the cells became senescent. The percent of total activity of the tetrameric form was comparable to the percent heat labile enzyme assayed at a given population doubling level. These results indicated that the observed increase in heat lability of G6PD with age may be due to a shift in equilibrium to the tetrameric form of the enzyme rather than the synthesis of aberrant enzyme molecules.

Cell Division↗

Glucose-6-phosphate dehydrogenase and NADPH-consuming enzymes in the rat olfactory bulb.

The resistance to oxidative stress is a multifactorial reaction involving the clustering of transcriptionally regulated genes. Because glucose-6-phosphate dehydrogenase (G6PD), the principal enzyme responsible for reducing power, is highly expressed in the olfactory bulb (OB), it is of interest to verify whether other enzymes utilizing NADPH are also highly expressed. The level and localization of G6PD- and NADPH-consuming enzymes, such as NADPH-cytochrome P450 oxidoreductase (P450R), glutathione reductase (GR), and NADPH-diaphorase (NADPH-d), were analyzed in the rat olfactory bulb (OB) by quantitative histochemistry and immunohistochemistry. The highest concentration of G6PD, P450R, and GR was observed in the olfactory nerve layer (ONL), suggesting a correlation in the expression of these enzymes at the gene level. Correlation in staining intensity between G6PD and NADPH-d activities occurred only in part of the ONL, some glomeruli, and scattered periglomerular cells. This peculiar distribution of NADPH-d could reflect a spatial patterning of the nose to bulb projections. Taken together, these results indicate that G6PD expression in the ONL could be related to the importance of generating a substantial supply of NADPH to sustain the detoxifying systems represented by GR and P450R reactions and, only in discrete zones, by NADPH-d activity.

Animals↗