930 resultados para Tetrahydrofolate Dehydrogenase


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Acute myeloid leukemia (AML) with a high white blood cell (WBC) count at presentation has been associated with an increased early mortality rate, usually secondary to leukostasis. However, the value of the WBC count at which there is a high risk of early death (ED) and the efficiency of supportive treatments remain unclear. In this report, a series of 187 consecutive adult patients with AML in our institution was reviewed. The outcome of 40 patients with WBC above 50 x 10(9) L(-1) (hyperleukocytosis) was compared to 147 patients with a leukocyte count lower than 50 x 10(9) L(-1). The group with hyperleukocytosis showed a significantly shorter OS (P < 0.0001) and a higher rate of ED (P = 0.0008). Even when the data from ED patients were removed from analysis, we still detected a shorter OS in patients with hyperleukocytosis (P = 0.0049), which suggests that high WBC number influences long-term survival, and not only ED. We also observed higher lactic dehydrogenase (LDH) and serum creatinine levels in the group of patients with hyperleukocytosis (P = 0.0003 and 0.0406, respectively). Besides considering all the patients with ED, we could observe higher levels of lactic dehydrogenase, a serum creatinine and nitrogen urea (P = 0.0056, P = 0.0008 and P < 0.0001, respectively). Pulmonary involvement was more frequent in patients with ED (P = 0.0277). In conclusion, hyperleukocytosis confers a poorer prognosis in patients with AML.

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Sulfite oxidase is a mitochondrial enzyme encoded by the SUOX gene and essential for the detoxification of sulfite which results mainly from the catabolism of sulfur-containing amino acids. Decreased activity of this enzyme can either be due to mutations in the SUOX gene or secondary to defects in the synthesis of its cofactor, the molybdenum cofactor. Defects in the synthesis of the molybdenum cofactor are caused by mutations in one of the genes MOCS1, MOCS2, MOCS3 and GEPH and result in combined deficiencies of the enzymes sulfite oxidase, xanthine dehydrogenase and aldehyde oxidase. Although present in many ethnic groups, isolated sulfite oxidase deficiency and molybdenum cofactor deficiency are rare inborn errors of metabolism, which makes awareness of key clinical and laboratory features of affected individuals crucial for early diagnosis. We report clinical, radiologic, biochemical and genetic data on a Brazilian and on a Turkish child with sulfite oxidase deficiency due to the isolated defect and impaired synthesis of the molybdenum cofactor, respectively. Both patients presented with early onset seizures and neurological deterioration. They showed no sulfite oxidase activity in fibroblasts and were homozygous for the mutations c.1136A>G in the SUOX gene and c.667insCGA in the MOCS1 gene, respectively. Widely available routine laboratory tests such as assessment of total homocysteine and uric acid are indicated in children with a clinical presentation resembling that of hypoxic ischemic encephalopathy and may help in obtaining a tentative diagnosis locally, which requires confirmation by specialized laboratories. (C) 2009 Published by Elsevier B.V.

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We have studied the variability of glutamate dehydrogenase (gdh) and small subunit ribosomal (SSU) rRNA coding genes of Giardia species in fecal samples isolated from wild and exotic animals in Brazil, and compared with homologous sequences of isolates from human and domestic animals characterized in previous studies. Cysts of Giardia duodenalis were obtained from feces of naturally infected monkeys (Alouatta fusca) (n = 20), chinchillas (Chinchilla lanigera) (n = 3), ostriches (Struthio camelus) (n = 2) and jaguar (Panthera onca) (n = 1). Assemblage AI was assigned to the unique isolate of jaguar. All the samples from monkeys, chinchillas, and ostriches were assigned to Assemblage B. There was little evolutionary divergence between the referred isolates and isolates described elsewhere. The Assemblage B isolates identified in this study were closely related to Assemblage BIV isolated from humans. The molecular identification of Assemblages A and B of G. duodenalis isolates from exotic and wild animals demonstrates that such hosts may be a potential reservoir for zoonotic transmission of G. duodenalis. (C) 2011 Elsevier B.V. All rights reserved.

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The aim of this study was to assess the effect of exogenous DNA and incubation time on the viability of bovine sperm. Sperm were incubated at a concentration of 5 x 10(6)/ml with or without plasmid pEYFP-NUC. Fluorescent probes, propidium iodide/Hoechst 33342, FITC-PSA and JC-1, were used to assess plasma membrane integrity (PMI), acrosome membrane integrity (AMI) and mitochondrial membrane potential (MMP) respectively at 0, 1, 2, 3 and 4 h of incubation. Exogenous DNA addition did not affect sperm viability; however, incubation time was related to sperm deterioration. Simultaneous assessment of PMI, AMI and MMP showed a reduction in the number of sperm with higher viability (integrity of plasma and acrosome membranes and high mitochondrial membrane potential) from 58.7% at 0 h to 7.5% after 4 h of incubation. Lower viability sperm (damaged plasma and acrosome membranes and low mitochondrial membrane potential) increased from 4.6% at 0 h to 25.99% after 4 h of incubation. When PMI, AMI and MMP were assessed separately we noticed a reduction in plasma and acrosome membrane integrity and mitochondrial membrane potential throughout the incubation period. Therefore, exogenous DNA addition does not affect sperm viability, but the viability is reduced by incubation time.

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The aim of this study was to evaluate the effects of infrared diode laser phototherapy (LP) on tissues of the submandibular gland (SMG) and parotid gland (PG). Wistar rats were randomly divided into experimental (A and B) and control (C) groups. A diode laser, 808 nm wavelength, in continuous wave mode, was applied to the PG, SMG and sublingual gland in the experimental groups on two consecutive days. The doses were 4 J/cm(2) and 8 J/cm(2), and total energy was 7 J and 14 J, respectively. The power output (500 mW) and power density (277 mW/cm(2)) were the same for both experimental groups. In order to visualize the area irradiated by the infrared laser, we used a red pilot beam (650 nm) with 3 mW maximum power for the experimental groups. For the control group, the red pilot beam was the only device used. The SMG and PG were removed after 1 week of the first irradiation. Total protein concentration, amylase, peroxidase, catalase and lactate dehydrogenase assays were performed, as well as histological analysis. Statistical tests revealed significant increase in the total protein concentration for groups A and B in the parotid glands (P < 0.05). Based on the results of this study, LP altered the total protein concentration in rats` parotid glands.

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Background Progress in identifying genetic factors protective against alcohol dependence (AlcD) requires a paradigm shift in psychiatric epidemiology. Aims To integrate analysis of research into the genetics of alcoholism. Method Data from prospective questionnaire and interview surveys of the Australian twin panel, and from a subsample who underwent alcohol challenge, were analysed. Results In men, effects of alcohol dehydrogenase ADH2*1/*2 genotype or high alcohol sensitivity (risk-decreasing), and of history of childhood conduct disorder, or having monozygotic co-twin or twin sister with AlcD (risk-increasing) were significant and comparable in magnitude. Religious affiliation (Anglican versus other) was associated with the ADH2 genotype, but did not explain the associations with AlcD symptoms. No protective effect of the ADH2*1/*2 genotype was observed in women. Conclusions The early onset and strong familial aggregation of AlcD, and opportunity for within-family tests of genetic association to avoid confounding effects, make epidemiological family studies of adolescents and young adults and their families a priority.

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The suitability of sedimentation equilibrium for characterizing the self-association of muscle glycogen phosphorylase b has been reappraised. Whereas sedimentation equilibrium distributions for phosphorylase b in 40 mM Hepes buffer (pH 6.8) supplemented with 1 mM AMP signify a lack of chemical equilibrium attainment, those in buffer supplemented additionally with potassium sulfate conform with the requirements of a dimerizing system in chemical as we:ll as sedimentation equilibrium. Because the rate of attainment of chemical equilibrium under the former conditions is sufficiently slow to allow resolution of the dimeric and tetrameric enzyme species by sedimentation velocity, this procedure has been used to examine the effects of thermodynamic nonideality arising from molecular crowding try trimethylamine N-oxide on the self-association behaviour of phosphorylase b. In those terms the marginally enhanced extent of phosphorylase b self-association observed in the presence of high concentrations of the cosolute is taken to imply that the effects of thermodynamic nonideality on the dimer-tetramer equilibrium are being countered by those displacing the T reversible arrow R isomerization equilibrium for dimer towards the smaller, nonassociating T state. Because the R state is the enzymically active form, an inhibitory effect is the predicted consequence of molecular crowding by high concentrations of unrelated solutes. Thermodynamic nonideality thus provides an alternative explanation for the inhibitory effects of high concentrations of glycerol, sucrose and ethylene glycol on phosphorylase b activity, phenomena that have been attributed to extremely weak interaction of these cryoprotectants with the T state of the enzyme.

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Background: The significant association between alcohol dehydrogenase (ADH)-2 genotype and alcohol-dependence risk, demonstrated in both Asian and non-Asian populations, suggests a link between the metabolism of alcohol (ethanol) and individual differences in susceptibility to dependence. Methods: We tested this hypothesis by following up on subjects who took part in the Alcohol Challenge Twin Study conducted in 1979-1981 and comparing the blood and breath alcohol results in that study between subjects who subsequently did or did not meet diagnostic criteria for lifetime alcohol dependence in 1992-1993. Results: Subjects who met DSM-III-R criteria for lifetime alcohol dependence at follow-up had higher blood and breath alcohol values after alcohol challenge than never-dependent subjects. Multivariate analysis showed independent effects of susceptibility to alcohol dependence and smoking status on blood alcohol concentrations, whereas habitual alcohol intake at the time of the initial study had marginally significant effects. The risk of alcohol dependence was 2-fold higher in men and 3-fold higher in women with blood or breath alcohol concentrations in the highest quartile than in the lowest quartile. Conclusions: In view of this association and the known genetic influences on both alcohol pharmacokinetics and alcohol dependence, it is probable that part of the heritability of dependence is mediated by genes (other than the known ADH2 and ADH3 polymorphisms) affecting alcohol metabolism.

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This article represents the proceedings of a workshop at the 2000 ISBRA Meeting in Yokohama, Japan. The chairs were Geoffrey M. Thiele and Simon Worrall. The presentations were (1) The chemistry of malondialdehyde-acetaldehyde (MAA) adducts, by Dean J. Tuma; (2) The formation and clearance of MAA adducts in ethanol-fed rats, by Simon Worrall; (3) Immune responses to MAA adducts may play a role in the development of alcoholic liver disease, by Lynell W. Klassen; (4) Unique biological responses to MAA-modifled proteins that may play a role in the development and/or progression of alcoholic liver disease, by Geoffrey M. Thiele; (5) MAA-adducted bovine serum albumin activates protein kinase C and stimulates interleukin-8 release in bovine bronchial epithelial cells, by Todd A. Wyatt; and (6) An enzyme immune assay for serum antiacetaldehyde adduct antibody using low-density lipoprotein-adduct and its significance in alcoholic liver injury and ALDH2 heterozygotes, by Naruhiko Nagata.

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The plasma membrane Ca2+ pump is a key regulator of cytosolic free Ca2+. Recent studies have demonstrated the dynamic expression of the plasma membrane Ca2+ pump in a variety of cell types. Furthermore, alterations in plasma membrane calcium pump activity have now been implicated in human disease. In this study, the development of a technique to quantitatively assess mRNA expression of the human plasma membrane Ca2+ ATPase (PMCA1) isoform of the plasma membrane Ca2+ pump, using a real-time reverse transcriptase-polymerase chain reaction (real-time RT-PCR) assay in a human breast epithelial cell line (MCF-7) is described. The sequences of the PMCA1 primers and probe for real-time RT-PCR are presented. The results also indicate that PMCA1 mRNA can be normalized to both 18S ribosomal RNA (18S rRNA) and human glyceraldehyde-3-phosphate dehydrogenase (hGAPDH) in MCF-7 cells. Real-time RT-PCR will be most useful in assessing PMCA1 mRNA expression in cases where only low amounts of RNA are available and/or when numerous samples must be assessed simultaneously. (C) 2001 Elsevier Science Inc. All rights reserved.

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The adaptations of muscle to sprint training can be separated into metabolic and morphological changes. Enzyme adaptations represent a major metabolic adaptation to sprint training, with the enzymes of all three energy systems showing signs of adaptation to training and some evidence of a return to baseline levels with detraining. Myokinase and creatine phosphokinase have shown small increases as a result of short-sprint training in some studies and elite sprinters appear better able to rapidly breakdown phosphocreatine (PCr) than the sub-elite. No changes in these enzyme levels have been reported as a result of detraining. Similarly, glycolytic enzyme activity (notably lactate dehydrogenase, phosphofructokinase and glycogen phosphorylase) has been shown to increase after training consisting of either long (> 10-second) or short (< 10-second) sprints. Evidence suggests that these enzymes return to pre-training levels after somewhere between 7 weeks and 6 months of detraining. Mitochondrial enzyme activity also increases after sprint training, particularly when long sprints or short recovery between short sprints are used as the training stimulus. Morphological adaptations to sprint training include changes in muscle fibre type, sarcoplasmic reticulum, and fibre cross-sectional area. An appropriate sprint training programme could be expected to induce a shift toward type Ha muscle, increase muscle cross-sectional area and increase the sarcoplasmic reticulum volume to aid release of Ca2+. Training volume and/or frequency of sprint training in excess of what is optimal for an individual, however, will induce a shift toward slower muscle contractile characteristics. In contrast, detraining appears to shift the contractile characteristics towards type IIb, although muscle atrophy is also likely to occur. Muscle conduction velocity appears to be a potential non-invasive method of monitoring contractile changes in response to sprint training and detraining. In summary, adaptation to sprint training is clearly dependent on the duration of sprinting, recovery between repetitions, total volume and frequency of training bouts. These variables have profound effects on the metabolic, structural and performance adaptations from a sprint-training programme and these changes take a considerable period of time to return to baseline after a period of detraining. However, the complexity of the interaction between the aforementioned variables and training adaptation combined with individual differences is clearly disruptive to the transfer of knowledge and advice from laboratory to coach to athlete.

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There have been few replicated examples of genotype x environment interaction effects on behavioral variation or risk of psychiatric disorder. We review some of the factors that have made detection of genotype x environment interaction effects difficult, and show how genotype x shared environment interaction (GxSE) effects are commonly confounded with genetic parameters in data from twin pairs reared together. Historic data on twin pairs reared apart can in principle be used to estimate such GxSE effects, but have rarely been used for this purpose. We illustrate this using previously published data from the Swedish Adoption Twin Study of Aging (SATSA), which suggest that GxSE effects could account for as much as 25% of the total variance in risk of becoming a regular smoker. Since few separated twin pairs will be available for study in the future, we also consider methods for modifying variance components linkage analysis to allow for environmental interactions with linked loci.

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The dietary supply of folates and their measurement are both affected, potentially, by the instability of some folates. Labile folates appear to be stabilized by binding to folate-binding protein (FBP); this paper reports measurements of that stabilization. The degradation rates of the very labile tetrahydrofolate (H(4)folate) and moderately labile 5-methyltetrahydrofolate (5-CH(3)H(4)folate) were measured with the compounds free or bound to either soluble or immobilized bovine milk FBP. Complexation increased stability from 2- to > 1000-fold, depending on buffer and temperature conditions. H(4)folate at 4degreesC and pH 6.7 appeared to be quite stable for > 100 d when bound to soluble FBP but had a half-life of < 1 h when free. Stabilization of milk folates may be a role of FBP and would improve the bioavailability of milk folate to newborns and other consumers.

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Cushing's syndrome is associated with hypertension in approximately 80% of cases. Hypertension contributes to the marked increased mortality risk of past or current Cushing's syndrome, largely because of increased cardiovascular risk. Observation of the pathophysiological effect of chronically elevated ACTH and cortisol values in patients with ectopic ACTH secretion complements the available data from acute studies of the effects of ACTH and glucocorticoid infusions in normal volunteers. In a retrospective case review, we identified 58 patients with Cushing's syndrome caused by ectopic ACTH secretion, who were treated at the National Institutes of Health between 1983-1997. The diagnosis of an ectopic ACTH cause was confirmed by inferior petrosal sinus sampling and/or pathologic examination of tumor. The commonest causes were bronchial carcinoid (40%) and thymic carcinoid (10%), but 18 of 58 (31%) patients had an unknown source of ectopic ACTH. Hypertension (systolic blood pressure >140 mmHg and/or diastolic blood pressure >90 mmHg in adults) was noted in 45 of 58 (78%) ectopic Cushing's patients, a prevalence similar to that noted in other endogenous Cushing's syndrome etiologies. Hypertension was severe, deemed to require 3 or more drugs by the treating physicians, in 26 of 58 (45%) patients. Hypokalemia was much more prevalent than in patients with other causes of Cushing's syndrome, affecting 33 of 58 (57%) patients. The range of plasma ACTH (17-1557 pg/mL, normal

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PRL and placental lactogen (PL) play key roles in maintaining the rodent corpus luteum through pregnancy. Suppressors of cytokine signaling (SOCS) have been shown to decrease cell sensitivity to cytokines, including PRL, and so here we have addressed the issue of whether luteolysis induced by prostaglandin F-2alpha (PGF(2alpha)) might up-regulate SOCS proteins to inhibit PRL signaling. In d 19 pregnant rats, cloprostenol, a PGF(2alpha) analog, rapidly induced transcripts for SOCS-3 and, to a lesser extent, SOCS-1. We also found increased SOCS-3 protein in the ovary by immunoblot and in the corpus luteum by immunohistochemistry. Increased SOCS-3 expression was preceded by an increase in STAT3 tyrosine phosphorylation 10 min after cloprostenol injection and was maintained for 4 h, as determined by gel shift and immunohistochemistry. Induction of SOCS-3 was accompanied by a sharp decrease in active STAT5, as determined by gel-shift assay and by loss of nuclear localized STAT5. Four hours after cloprostenol administration, the corpus luteum was refractory to stimulation of STAT5 by PRL administration, and this was not due to down-regulation of PRL receptor. Therefore, induction of SOCS-3 by PGF(2alpha) may be an important element in the initiation of luteolysis via rapid suppression of luteotropic support from PL.