952 resultados para inborn errors of metabolism
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Mode of access: Internet.
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Mode of access: Internet.
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On spine: South Carolina law reports.
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"Vol. I." No more published. Cf. Hicks, Legal research, 1942.
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Propofol infusion syndrome (PRIS) is a rare but often fatal complication as a result of large doses of propofol infusion (4–5 mg/kg/hr) for a prolonged period (>48 h). It has been reported in both children and adults. Besides large doses of propofol infusion, the risk factors include young age, acute neurological injury, low carbohydrate and high fat intake, exogenous administration of corticosteroid and catecholamine, critical illness, and inborn errors of mitochondrial fatty acid oxidation. PRIS manifestation include presence of metabolic acidosis with a base deficit of more than 10 mmol/l at least on one occasion, rhabdomyolysis or myoglobinuria, acute renal failure, sudden onset of bradycardia resistant to treatment, myocardial failure, and lipemic plasma. The pathophysiology of PRIS may be either direct mitochondrial respiratory chain inhibition or impaired mitochondrial fatty acid metabolism mediated by propofol. We report a case of supermorbidly obese patient who received propofol infusion by total body weight instead of actual body weight and developed PRIS.
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The biochemistry of most metabolic pathways is conserved from bacteria to humans, although the control mechanisms are adapted to the needs of each cell type. Oxygen depletion commonly controls the switch from respiration to fermentation. However, Saccharomyces cerevisiae also controls that switch in response to the external glucose level. We have generated an S. cerevisiae strain in which glucose uptake is dependent on a chimeric hexose transporter mediating reduced sugar uptake. This strain shows a fully respiratory metabolism also at high glucose levels as seen for aerobic organisms, and switches to fermentation only when oxygen is lacking. These observations illustrate that manipulating a single step can alter the mode of metabolism. The novel yeast strain is an excellent tool to study the mechanisms underlying glucose-induced signal transduction. © 2004 European Molecular Biology Organization.
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Using ionspray tandem mass spectrometry the glutathione conjugate SMG was identified as a biliary metabolite of DMF in rats (0.003% of a dose of 5OOmg/kg DMF i.p.). Formation of this metabolite was increased five fold after induction of CYP2E1 by acetone, and was inhibited to 20% of control values following pretreatment with disulfrram. Generation of SMG from DMF in vivo was shown to exhibit a large kinetic deuterium isotope effect (KWKD=10.1 ± 1.3), which most likely represents the product of 2 discrete isotope effects on N-demethylation and formyl oxidation reactions.The industrial solvent N,N-dimethylformamide (DMF) and the investigational anti-tumour agent N-methylformamide (NMF) cause liver damage in rodents and humans. The hepatotoxicity of N-alkylformamides is linked to their metabolism to N-alkylcarbamic acid thioesters. The enzymatic details of this pathway were investigated. Hepatocytes isolated from BALB/c mice which had been pretreated with acetone, an inducer of the cytochrome P-450 isozyme CYP2E1, were incubated with NMF (10mM). NMF caused extensive toxicity (> 90% ) as determined by lactate dehydrogenase (LDH) release, compared to cells from untreated animals. Incubation of liver cells with NMF for 6 hrs caused 60±17% LDH release whilst in the presence of DMSO (10mM), an alternative substrate for CYP2E1, LDH release was reduced to 20±10% . The metabolism of NMF to S-(N-methylcarbamoyl)glutathione (SMG) was measured in incubates with liver microsomes from mice, rats or humans. Metabolism of NMF was elevated in microsomes isolated from rats and mice pretreated with acetone, by 339% and 183% respectively. Pretreatment of animals with 4-methylpyrazole induced the metabolism of NMF to 280% by rat microsomes, but was without effect on NMF metabolism by mouse microsomes. The CYP2E1 inhibitors or alternative substrates diethyl dithiocarbamate (DEDTC), p-nitrophenol (PNP) and dimethyl sulphoxide (DMSO) strongly inhibited the metabolism of NMF in suspensions of rat liver microsomes, at concentrations which did not effect aminopyrine N-demethylation. The rate of metabolism of NMF to SMG in human microsomes correlated (r> 0.8) with the rate of metabolism of chlorzoxazone, a CYP2E1 probe. A polyclonal antibody against rat CYP2E1 (10mg/nmol P-450) inhibited NMF metabolism in microsomes from rats and humans by 75% and 80% , respectively. The amount of immunoblottable enzyme in human microsomes, determined using an anti-rat CYP2E1 antibody, correlated with the rate of NMF metabolism (r> 0.8). Purified rat CYP2E1 catalysed the generation of SMG from NMF. Formation of the DMF metabolite N-hydroxymethyl-N-methylformamide (HMMF) in incubations with rat liver microsomes was elevated by 200% following pretreatment of animals with acetone. Co-incubation with DEDTC (100μM) inhibited HMMF generation from DMF by 88% . Co-incubation of DMF (10mM) with NMF (1mM) inhibited the formation of SMG by 95% . A polyclonal antibody against rat CYP2E1 (10mg/nmol P-450) inhibited generation of HMMF in incubates with rat and human liver microsomes by 68.4% and 67.5% , respectively. Purified rat CYP2E1 catalysed the generation of HMMF from DMF. Using ionspray tandem mass spectrometry the glutathione conjugate SMG was identified as a biliary metabolite of DMF in rats (0.003% of a dose of 5OOmg/kg DMF i.p.). Formation of this metabolite was increased five fold after induction of CYP2E1 by acetone, and was inhibited to 20% of control values following pretreatment with disulfrram. Generation of SMG from DMF in vivo was shown to exhibit a large kinetic deuterium isotope effect (KHKD=10.1 ± 1.3), which most likely represents the product of 2 discrete isotope effects on N-demethylation and formyl oxidation reactions.
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Obestatin is a 23-amino acid C-terminally amidated gastrointestinal peptide derived from preproghrelin and which forms an alpha helix. Although obestatin has a short biological half-life and is rapidly degraded, it is proposed to exert wide-ranging pathophysiological actions. Whilst the precise nature of many of its effects is unclear, accumulating evidence supports positive actions on both metabolism and cardiovascular function. For example, obestatin has been reported to inhibit food and water intake, body weight gain, and gastrointestinal motility, and to also mediate promotion of cell survival and prevention of apoptosis. Obestatin-induced increases in β-cell mass, enhanced adipogenesis and improved lipid metabolism have been noted along with upregulation of genes associated with β-cell regeneration, insulin production and adipogenesis. Furthermore, human circulating obestatin levels generally demonstrate an inverse association with obesity and diabetes, whilst the peptide has been shown to confer protective metabolic effects in experimental diabetes, suggesting that it may hold therapeutic potential in this setting. Obestatin also appears to be involved in blood pressure regulation and to exert beneficial effects on endothelial function, with experimental studies indicating that it may also promote cardioprotective actions against, for example, ischaemia-reperfusion injury. This review will present a critical appraisal of the expanding obestatin research area and discuss the emerging therapeutic potential of this peptide for both metabolic and cardiovascular complications of diabetes.
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Background: Infantile Onset Pompe Disease (IOPD) is a rare autosomal recessive neuromuscular disorder. It is associated with cardiomegaly, hypotonia, paresis, and death in the first year of life. Since 2006, following the use of Alglucosidase alfa as Enzyme Replacement Therapy (ERT), the patients’ survival is improved to a noticeable extent. Objectives: The purpose of this study is to examine the outcome of IOPD patients in South of Iran and the degree of responsiveness to ERT. Patients and Methods: All patients who were diagnosed with IOPD on the bases of clinical symptoms, and enzyme assay on dried blood spot, were included in the study; and were followed up regarding cardiac function, locomotor activity, and cognition. Results: Six patients with IOPD were identified. All these six patients suffered from Hypertrophic Cardiomyopathy (HCM). Four (67%) of them also had generalized hypotonia. Three patients expired during the first weeks due to severe respiratory infection. One of them also got involved with Acute Cardiopulmonary Failure while receiving the fifth dose of ERT; and expired. However, the remaining two patients had a significant improvement after the maximum of 117 weeks of following up both cardiac and locomotor findings. These two patients were the same patients who showed cardiac symptoms from the beginning but did not have generalized hypotonia. Conclusions: Although ERT has a significant effect on enhancing the survival of IOPD patients, it should be associated with meticulous heart-respiratory cares during the first months of treatment and preventing infection especially nosocomial infections.
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Spondylocostal dysostosis (SCD) is a genetic disorder characterized by vertebral segmentation and formation defects associated with changes of the ribs. Autosomal dominant and recessive modes of inheritance have been reported. Methylmalonic aciduria (MMA) is an inborn error of propionate or cobalamin metabolism. It is an autosomal recessive disorder and one of the most frequent forms of branched-chain organic acidurias. Here we report on a case of a Brazilian boy with both diseases. As we know, it is the first case in the literature with the occurrence of both SCD and MMA-the first a skeletal disease and the latter an inborn error of metabolism.
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BACKGROUND: Methylmalonic aciduria is an inborn error of metabolism characterized by accumulation of methylmalonate (MMA), propionate and 2-methylcitrate (2-MCA) in body fluids. Early diagnosis and current treatment strategies aimed at limiting the production of these metabolites are only partially effective in preventing neurological damage. METHODS: To explore the metabolic consequences of methylmalonic aciduria on the brain, we used 3D organotypic brain cell cultures from rat embryos. We challenged the cultures at two different developmental stages with 1 mM MMA, propionate or 2-MCA applied 6 times every 12 h. In a dose-response experiment cultures were challenged with 0.01, 0.1, 0.33 and 1 mM 2-MCA. Immunohistochemical staining for different brain cell markers were used to assess cell viability, morphology and differentiation. Significant changes were validated by western blot analysis. Biochemical markers were analyzed in culture media. Apoptosis was studied by immunofluorescence staining and western blots for activated caspase-3. RESULTS: Among the three metabolites tested, 2-MCA consistently produced the most pronounced effects. Exposure to 2-MCA caused morphological changes in neuronal and glial cells already at 0.01 mM. At the biochemical level the most striking result was a significant ammonium increase in culture media with a concomitant glutamine decrease. Dose-response studies showed significant and parallel changes of ammonium and glutamine starting from 0.1 mM 2-MCA. An increased apoptosis rate was observed by activation of caspase-3 after exposure to at least 0.1 mM 2-MCA. CONCLUSION: Surprisingly, 2-MCA, and not MMA, seems to be the most toxic metabolite in our in vitro model leading to delayed axonal growth, apoptosis of glial cells and to unexpected ammonium increase. Morphological changes were already observed at 2-MCA concentrations as low as 0.01 mM. Increased apoptosis and ammonium accumulation started at 0.1 mM thus suggesting that ammonium accumulation is secondary to cell suffering and/or cell death. Local accumulation of ammonium in CNS, that may remain undetected in plasma and urine, may therefore play a key role in the neuropathogenesis of methylmalonic aciduria both during acute decompensations and in chronic phases. If confirmed in vivo, this finding might shift the current paradigm and result in novel therapeutic strategies.
Bebé Obeso Dislipémico con Displasia Optica Bilateral, Hipotiroidismo Terciario y Retraso Madurativo
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Multiple Sulfatase Deficiency (MSD; OMIM 272200) is a rare autosomal recessive inborn error of metabolism caused by mutations in the sulfatase modifying factor 1 gene, encoding the formyglycine-generating enzyme (FGE), and resulting in tissue accumulation of sulfatides, sulphated glycosaminoglycans, sphingolipids and steroid sulfates. Less than 50 cases have been published so far. We report a new case of MSD presenting in the newborn period with hypotonia, apnoea, cyanosis and rolling eyes, hepato-splenomegaly and deafness. This patient was compound heterozygous for two so far undescribed SUMF1 mutations (c.191C¿>¿A; p.S64X and c.818A¿>¿G; p.D273G).
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Primary hyperoxaluria type I is a rare inborn error of metabolism caused by a deficiency of a liver-specific peroxisomal enzyme. It manifests by increased oxalate production that ultimately results in kidney failure, due to urolithiasis and nephrocalcinosis, and finally induces systemic oxalosis and risk of premature death. Primary hyperoxaluria type 2 is mainly responsible of urolithiasis. Enteric hyperoxaluria is a commonly seen adverse event of Crohn disease or after extensive intestinal resection. These affections represent the main etiologies of massive hyperoxaluria. If not recognized very soon and adequately treated, these conditions can progress rapidly to end stage renal failure.