Analysis of a 452C/T single nucleotide polymorphism in γ-glutamyl hydrolase gene in children with acute leukemia / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the distribution of γ-glutamyl hydrolase gene (GGH) 452C/T genotype and allele frequency in children with acute leukemia (AL) and healthy children.</p><p><b>METHODS</b>Bone marrow samples from 92 children with AL and peripheral blood samples from 124 healthy children were obtained to prepare complementary DNAs (cDNAs). The cDNAs were analyzed for a GGH 452C/T polymorphism by reverse transcriptase-polymerase chain reaction-denaturing gradient gel electrophoresis (RT-PCR-DGGE) and direct sequencing.</p><p><b>RESULTS</b>The frequencies of the AL patients with TT, CT and CC genotypes were 2.2%, 13.0% and 84.8%, and the frequencies of the control children were 1.6%, 16.9% and 81.5%, respectively. There was no significant difference in GGH genotype or T allele frequency between the two groups (P> 0.05). However, the T allele frequency in Han Chinese children was significantly different from those reported in Japanese, Mexican and African-American populations.</p><p><b>CONCLUSION</b>The frequency of 452C/T polymorphism of GGH gene in Han Chinese children has been determined. The results suggested that an ethnic difference may exist.</p>

Folate Content of Fast Foods and Processed Foods

A trienzyme extraction method (use of alpha-amylase, protease and folate conjugase) for food folate assay has been used to release folate from the food matrix. In order to reduce the incubation time with three enzymes, folate values were compared between two incubation protocols; separate incubation (SI, incubated with alpha-amylase and conjugase separately for 2 hours after protease treatment) and combined incubation (CI, incubated with alpha-amylase and conjugase together for 2 hours after protease treatment) using 88 food items from 12 kinds of fast foods and processed foods. We found that folate values by CI were comparable to or higher than those by SI, indicating that CI might be a better extraction procedure to shorten the entire incubation time. We measured folate contents in 49 fast foods and 26 processed foods by microbiological assay after CI. Mean folate contents of one serving of various burgers ranged from 43.1 to 62.0 microgram. One serving of French fries, pizza, sandwich and triangled kimbab contained a mean of 53.3, 28.4, 47.4, and 25.7 microgram of folate, respectively. Folate contents of non-alcoholic beverages were very low, ranging from 1.0 to 5.2 microgram/100 g. Some of our values were comparable to the values in the folate database published in Korean Nutrition Society, however, some of the published values were 140 times higher than the measured values in this study. Folate values measured by the more recent modifications here can be used to update Korean folate database to accurately estimate dietary folate intake

Benzene toxicity in shoemakers and role of vitamin A [as antioxidant]

The burden of liver disease in Egypt is exceptionally high. Unquestionably, additional factors contributing to liver disease burden remain to be elucidated. Human exposure to benzene in work environment is a gbbat occupational health problem; it may represent a risk factor for hepatotoxicity, liver cancer and hematotoxicity. The present study aimed to evaluate the hazardous effects of occupational exposure to benzene on liver and blood, as well as the protective role of the antioxidant [vitamin A] on hematotoxic and hepatotoxic effects among shoemakers who exposed to benzene. Twenty hundred and fifty workers were enrolled in this study after taking an informed consent; 140 occupationally exposed workers to benzene for more than 3 years [workers group; subdivided into non-treated and treated with vitamin A], and 110 workers never occupationally exposed to benzene [control group]. The benzene urine level, complete blood counts [CBC5], the liver enzymes, and the tumor marker, alphafetoprotein [AFP] were estimated. The benzene level in urine samples was significantly increased in shoemakers group. Benzene exposed non-treated workers showed significant increase in the liver enzymes and AFP, while the CBCs were significantly lower compared with both control group and benzene exposed treated group with vitamin A. Occupational exposure to benzene found to have hazardous effects, which were reflected on CBCs, liver enzymes, and AFP. Additionally, the vitamin A was observed to be effectively potent in ameliorating the haematotoxic and hepatotoxic effects in exposed workers. Periodic medical care and CBCs in combination with urinary benzene [UB] level were recommended in benzene workers

Homocysteine level in renal transplant recipients and its correlation to glomerular filtration rate, cyclosporine level and folate level

Cardiovascular disease [CVD] is the most common cause of death after renal transplantation [RT]. Hyperhomocysteinemia is identified as a risk factor for CVD. RT recipients [RTRs] have an excess prevalence of hyperhomocysteinemia. The objectives of this study were to determine homocysteine [tHCY] level in stable RTRs and correlate its level to graft function, cyslosporine level and folate level. Twenty RTRs of 1[st] living renal allografts, 16 males and 4 females with a mean age of 44.1 +/- 5.1 years and a transplant duration of 22.2 +/- 12.6 months were included in this study. Their mean serum creatinine, blood urea and GFR were 1.5 +/- 0.6 mg/dL, 63 +/- 27.7 mg/dL and 53.9 +/- 32.8 ml/ min respectively. Hyperhomocysteinemia was recorded in all RTRs, mild in 13 [65%] and moderate in 7 [35%] with a mean of 27.9 +/- 12.8 umol/L. Plasma folate level was low [4.5 +/- 5.5 ng/mL]. A significant positive correlation was recorded between tHCY level and both blood urea and serum creatinine [r 0.529, 0.279 respectively, P < 0.05]. There was a significant negative correlation between tHCY level and both GFR and plasma folate level [r - 0.375, - 0.416 respectively, P < 0.05]. No correlation between tHCY level and both duration of renal transplantation and cyclosporine level was recorded. In conclusion, inadequate folate level and or failure to restore normal renal function may be relevant to hyperhomocysteinemia observed in RTRs. tHCY level lowering can be achieved safely, rapidly and in-expensively with B-vitamin intervention

Prevalence of folate deficiency and hyperhomocysteinemia in a developing country: results from a large population study in Venezuela

To evaluate the prevalence of hyperhomocysteinemia in apparently healthy individuals and its relationship to the classical cardiovascular risk factors and nutritional and genetic determinants in a developing country a randomized crosssectional study was made in the Venezuelan population. Apparently healthy subjects (N = 3400; 9 – 60 yr) recruited, on a voluntary basis, from urban and rural areas in 9 states of the country which gather more than 60% of the total population. A Clinical and anthropometric evaluation, fasting plasma glucose, creatinine, blood lipids, fibrinogen, C-reactive protein, plasma total homocysteine (tHcy), folic acid and vitamin B12 were done in all subjects. The C677 --> T polymorphism of MTHFR was evaluated in a random sub-sample of the mixed-blood population (N = 535) and in a sample of Venezuelan blacks (N = 115). Final analysis was done on 3062 subjects (1608 females, 1454 males). An important deficiency in plasma folate was found (~ 50 percent of recommended value), in 86.0 percent of the population. Mean value for tHcy stays below 10.5 μmol/L for both genders in all age ranges studied. Hyperhomocysteinemia (> 12 μm/L) is found in 12 percent of females and 26 percent of males. MTHFR polymorphismreflects the spanish genic penetration. There is no association between hyperhomocysteinemia and the polymorphism. Hyperhomocysteinemia in our population is mainly related to marked deficiency in folic acid. The relatively lower mean values of tHcy, compared to developed countries, seem related to a general nutritional deficit.

La prevalencia de hiperhomocisteinemia y su relación con determinantes genéticos, nutricionales y factoresclásicos de riesgo cardiovascular, fue evaluada a través de un estudio epidemiológico, al azar, de tipo corte transversal, en una muestra razonablemente representativa de la población en Venezuela para el período del estudio. Se evaluaron sujetos aparentemente sanos (n = 3400; de 9 a 60 años de edad), provenientes de áreas rurales y urbanas de 9 estados del país. A todos los sujetos se les realizó una evaluación clínica y antropométrica y se les determinó glucosa sanguínea en ayunas, perfil lipídico, creatinina, fibrinógeno, proteína C reactiva, homocisteína total plasmática (tHcy), ácido fólico, vitamina B12. El polimorfismo MTHFR C677 T fue evaluado en una muestra al azar total de 650 sujetos (Mestizo = 535; Negros = 115). La muestra total analizada fue de 3062 sujetos (Femeninos = 1608; Masculinos = 1454). Se encontró una importante deficiencia de ácido fólico (86% de la población tiene valores cercanos al 50 por ciento del valor de folato recomendado). EL valor promedio de tHcy fue menor de 10,5 μM para ambos sexos en todos los grupos etarios evaluados. La prevalencia de hiperhomocisteinemia (>12 μM) fue de 12 por ciento en mujeres y 26 por ciento en hombres. El polimorfismo MTHFR C677 T, refleja la penetración génica española. La prevalencia de hiperhomocisteinemia en la población venezolana está principalmente relacionada con la deficiencia de ácido fólico.

Bases moleculares de la función excretora de tipo hepatobiliar de la placenta / Molecular basis of excretory function placental hepatobiliary type

The liver plays an important excretory role eliminating from the body potentially toxic compounds that are xenobiotics or produced endogenously, such as bile acids and biliary pigments. This involves both transport and biotransformation processes. During intrauterine life, the inmature fetal liver cannot carry out this function. Therefore, the placenta performs a hepatobiliary-like excretory role, transferring cholephilic compounds from the fetus to the mother. The similarity of this function in the placenta and the adult liver is probably accounted for by the presence in both organs of proteins of the OATP family, involved in the uptake of organic anions across the basolateral membrane of several epithelia, and of members of the superfamily of ATP-binding cassette (ABC) proteins, which are involved in the export of substances out of many different cells. Thus, several studies have shown that, in addition to a difussional component, that may become particularly important for unconjugated bilirubin, the main mechanisms for bile acids and bilirubin transplacental transfer from the fetus to the mother are carrier-mediated transport systems, which have vectorial properties and also play an important role in the placental barrier by preventing or reducing the net flux of noxious substances from the mother to the fetus.

El hígado juega un papel determinante en la excreción de sustancias potencialmente tóxicas de origen externo o producidas por el organismo, como ácidos biliares y bilirrubina. Esta función implica tanto procesos de transporte como de biotransformación. Durante la vida intrauterina, el hígado fetal no es aún capaz de realizar esta función, por lo que es la placenta la que asume un papel excretor similar al que desempeña el sistema hepatobiliar en el adulto. La similitud entre ambas funciones se debe a la presencia en ambos órganos de proteínas transportadoras de la familia OATP, que llevan a cabo la captación de aniones orgánicos en varios epitelios, y de miembros de la superfamilia de proteínas ABC ("ATP-binding cassette"), capaces de bombear al exterior celular una gran variedad de sustancias. Estudios recientes demostraron que, además de un componente difusional, que es más relevante en el caso de la bilirrubina no conjugada, la vía mayoritaria en la transferencia placentaria de ácidos biliares y bilirrubina está mediada por sistemas de transporte que, en conjunto, presentan características de vectorialidad feto-materna, y que por ello también juegan un papel en la barrera placentaria reduciendo el flujo de sustancias nocivas desde la madre al feto.

Assessment of the role of hypephomccysteinemia and its metabolic consequences in the vascular access thrombosis among hemodialysis patients

The aim of this work was, to determine whether hyperhomocysteinemia and its metabolic consequences are associated with vascular access thrombosis in patients with end stage renal disease [ESRD], undergoing chronic hemodiahysis [HD]. This study included 3 groups. Group I: 15 ESRD patients on regular HD, with history of more than one episode of vascular access thrombosis. Group II: 15 ESRD patients on regular HD, with no episodes of vascular access thrombosis. Group III: 10 healthy, age and sex matched individuels as a control group. Plasma total homocysfeine [tHcy] and Von Willebrand Factor [vWF] were estimated by ELISA. Determination of plasma folate was done by Radioimmunoassay [RIA]. Plasma glutathione peroxidase activity was estimated by modified Paglia and Valentine method. Plasma methionine and cysteine levels were estimated by amino acid autoanalyser. plasma Hcy levels of both HD groups [GI and GII] were significantly higher than control groups [GIII] [F value = 44,487, P<0.0001], while no significant difference was found between GI and GII. Plasma folic acid levels of both patients' groups were significantly higher than control group [F value = 29.063, P<0.0001], while there was no significant difference between its level in GI and GII. Plasma vWF of HD patients with vascular access thrombosis [GI] was significantly higher than that of both GII and GIII and that of GII was significantly higher than GIII [F value = 62.010, P<0.0001]. Plasma glutathione peroxidase activity of both HD groups [GI and GII] was significantly lower than the control group [GIII] [F value = 69.446, P<0.0001], also its activity in patients with vascular access thrombosis [GI] was significantly lower than that of patients without vascular access thrombosis [GII]. Plasma cysteine and methionine levels of both HD groups were not significantly different from control group, also there was no significant difference in their levels between GI and GII. Plasma Hcy levels showed no significant correlation with number of vascular access thrombosis, whereas it showed a significant positive correlation with plasma vWF [r = 0.474, P<0.01] and negative correlation with plasma glutathione peroxidase activity [r = 0.643, P<0.0001]. From the previous study we concluded that: Hyperhomocyteinemia is not a direct cause of vascular access thrombosis. It is linked with increased plasma vWF levels. Endlothelial injury induced by hyperhomocysteinemia may be the cause. The lower levels of plasma glutathione peroxidase activity reflect increased oxidative stress induced by hyperhomocyteinemia in hemodialysis patients

Denaturation of pteroylpoly-gamma-glutamyl hydrolase from chicken liver by urea, thiourea and guanidine hydrochloride: altered catalytic properties of the enzyme activated by urea.

The effects of varying concentrations of urea, thiourea and guanidine hydrochloride on the enzyme activity and the isoenzymic polypeptide association of pteroylpoly-gamma-glutamyl hydrolase (EC 3.4.22.12) from chicken liver were studied. Incubation of the enzyme at 4 degrees C with low concentrations of the buffered (100 mM sodium acetate containing 1% ascorbate, pH 4.1) solutions of urea (0.55 M) and guanidine hydrochloride (0.05 M) resulted in stimulation (5- and 2-fold respectively) of the activity of the enzyme whereas at higher concentrations of the denaturants (6 M urea, 1 M thiourea or 2 M guanidine hydrochloride) the enzyme was completely inactivated. However, there was no enzyme activation in response to thiorea treatment. Under specific denaturing conditions the association of two isoenzymic polypeptides was studied. The 0.55 M urea- and 0.05 M guanidine hydrochloride-activated enzyme displayed its disaggregated nonidentical polypeptides I and II (M(r) = 41,000 and 17,300 respectively) on Sephadex G-100 gel filtration, SDS-PAGE and sedimentation analyses. The 8 M urea- and 3 M guanidine hydrochloride-inactivated enzyme on the other hand exhibited a single protein aggregate species of an M(r), 57,000 like the native enzyme. Both unmodified native enzyme and the pCMB-modified PtepolyGlu hydrolase responded similarly to these denaturants. The two constituent active polypeptides polyp-I and polyp-II of the heterodimeric gamma-glutamyl glutamyl hydrolase are dissociated in the presence of 0.55 M urea as evident from the PAGE analyses. Some catalytic properties of the activated enzyme were studied and compared with those of the native enzyme. The urea-activated enzyme displayed a shift in the second pH optimum of the double pH-activity profile (optima at pH 4.1 and pH 5.2) from pH 5.2 to pH 6.0. The activated enzyme has a Km value of 0.59 x 10(-6) M (Vmax, 0.10) for 5-CH3-H4PteGlu4 while the native enzyme has the Km of 0.83 x 10(-6) M (Vmax, 0.03) for this substrate. When the reaction mixtures were incubated with the urea-activated gamma-glutamyl hydrolase, a maximum stimulatory effect on the enzyme activity was observed with the bivalent metal ion Ca2+ whereas the most potent inhibitory effect was observed with the trivalent anion citrate.