Aumento de estresse oxidativo no sangue de pacientes com ostomia / Increased oxidative stress in the blood of ostomy patients

ABSTRACT BACKGROUND: Ostomy is a surgical procedure that creates a stoma that aims to construct a new path for the output of feces or urine. The relationship of oxidative stress (OxS) markers in patients with ostomy is still poorly described. OBJECTIVE: The present study was aimed at investigating the changes in oxidative stress parameters in peripheral blood collected from ostomy patients when compared with a healthy control group. METHODS: It was evaluated 29 ostomy patients and 30 healthy control patients. The oxidative stress parameters evaluated were: lipid peroxidation [lipid hydroperoxide (LPO), 8-isoprostane (8-ISO) and 4-hydroxynonenal (4-HNE)], protein oxidation and nitration [carbonyl and 3-nitrotyrosine (3-NT)] and DNA oxidation [8-hydroxy-2'-deoxyguanosine (8-OHDG)] in serum from ostomy patients compared to health controls. RESULTS: The data showed an increase of LPO, 8-ISO, 4-HNE, 3-NT and 8-OHDG in serum collected from ostomy patients when compared to healthy controls. CONCLUSION: The findings support the hypothesis that ostomy triggers the oxidative stress observed in the blood collected from these patients.

RESUMO CONTEXTO: Ostomia é um procedimento cirúrgico que cria um estoma com objetivo de construir um novo caminho para a saída das fezes ou urina. A relação dos marcadores de estresse oxidativo em pacientes ostomizados ainda é pouco descrita. OBJETIVO: O presente estudo tem como objetivo investigar as alterações dos parâmetros de estresse oxidativo em sangue de pacientes ostomizados comparados a controles saudáveis. MÉTODOS: Foram avaliados 29 pacientes ostomizados e 30 controles saudáveis. Os parâmetros de estresse oxidativo avaliados foram: peroxidação lipídica [hidroperóxido de lipídio (LPO), 8-isoprostano (8-ISO) e 4-hidroxinonenal (4-HNE)], oxidação e nitração de proteínas [carbonila e 3-nitrotirosina (3-NT)] e oxidação do DNA [8-hidroxi-2'-desoxiguanosina (8-OHDG)] em soro de pacientes ostomizados comparados a controles saudáveis. RESULTADOS: Os dados mostraram um aumento de LPO, 8-ISO, 4-HNE, 3-NT e 8-OHDG em soro de pacientes ostomizados em comparação a controles saudáveis. CONCLUSÃO: Os achados sustentam a hipótese de que a ostomia desencadeia o estresse oxidativo observado no sangue coletado destes pacientes.

A novel missense mutation pattern of the GCH1 gene in dopa-responsive dystonia

Dopa-responsive dystonia (DRD) is an inherited metabolic disorder now classified as DYT5 with two different biochemical defects: autosomal dominant GTP cyclohydrolase 1 (GCH1) deficiency or autosomal recessive tyrosine hydroxylase deficiency. We report the case of a 10-years-old girl with progressive generalized dystonia and gait disorder who presented dramatic response to levodopa. The phenylalanine to tyrosine ratio was significantly higher after phenylalanine loading test. This condition had two different heterozygous mutations in the GCH1 gene: the previously reported P23L mutation and a new Q182E mutation. The characteristics of the DRD and the molecular genetic findings are discussed.

Distonia dopa-responsiva (DRD), classificada como DYT5, é um erro inato do metabolismo que pode ser causado por dois diferentes tipos de defeito bioquímico: deficiência de GTP ciclo-hidrolase 1 (GCH1) (autossômica dominante) ou de tirosina hidroxilase (autossômica recessiva). Descrevemos o caso de menina de 10 anos com distonia generalizada progressiva e alteração da marcha com importante melhora após uso de levodopa. A relação fenilalanina/tirosina estava aumentada após teste de sobrecarga com fenilalanina. O estudo molecular mostrou que o paciente apresenta uma combinação hererozigótica de mutação no gene GCH1: a já conhecida mutação P23L e uma nova mutação Q182E. Discutem-se as características da DRD e as alterações genéticas possíveis.

HD is beneficial for enzymatic conversion of some amino-acids in the elderly

Many different causes of abnormal amino acid profile in uremic patients including: inadequate nutritional intake, uremic disturbances in amino acid metabolism, loss or fibrosis of renal tissues, metabolic acidosis and hormonal derangement. Some of these factors; such as metabolic acidosis are particularly corrected with dialytic therapy; but others such as decreased intake or hormonal disturbances may persist or worsen after initiation of dialysis. This study was done to investigate the plasma amino acids profile in uremic elderly patients. The present study was carried out on three matched groups: [G1] on HD, [G2] CRF and a control. A significant uniform decrease of Threonine, Valine and Leucine in both HD and CRF. However, a peculiar situation of significant increase in phenylalanine in HD in comparison to CRF and to control. This is similar to the significant increase of Arginine in HD group in comparison to the others. In contrast, phenylalanine was significantly decreased in CRF in comparison to both HD group and the control. The latter was similar to the decrease of Leucine in CRF in comparison to the other two groups. Hence, Phenylalanine was the only AA that was found to be significantly increased in HD and significantly decreased in CRF in comparison to control. Moreover, only Phenylalanine and Arginine were significantly increased in HD group in contrast to the rest of the essential amino-acids, which showed either decrease or no change. Tyrosine and lysine were significantly lower in pre -dialysis CRF group in comparison to patients on HD and the control. This may imply that HD can correct the deficiency of tyrosine and lysine in uremic patients probably due to less inhibition of phenylalanine hydrorxylase. Inter-conversion of phenylalanine to tyrosine was reported to be impaired in CRF; whereas tyrosine metabolism per se does not seem to be grossly affected by uremia. However; Serine was significantly lower in both groups of uremic patients in the current study compared with the control group, with no significant difference in-between pre -dialysis patients and patients on HD. In conclusion, our study showed that HD may be beneficial in restoring the enzymatic turnover of certain amino-acids including: Phenylalanine hydroxylase to normalize tyrosine plasma level, Arginine synthetase to convert citrulline to Arginine. On the other hand, HD may be injurious to the production of other amino-acids like serine due to complete lost of the renal tissue that is responsible of its production from glycine

Protein 3-nitrotyrosine formation during Trypanosoma cruzi infection in mice

Nitric oxide (ÀNO) is a diffusible messenger implicated in Trypanosoma cruzi resistance. Excess production of ÀNO and oxidants leads to the generation of nitrogen dioxide (ÀNO2), a strong nitrating agent. Tyrosine nitration is a post-translational modification resulting from the addition of a nitro (-NO2) group to the ortho-position of tyrosine residues. Detection of protein 3-nitrotyrosine is regarded as a marker of nitro-oxidative stress and is observed in inflammatory processes. The formation and role of nitrating species in the control and myocardiopathy of T. cruzi infection remain to be studied. We investigated the levels of ÀNO and protein 3-nitrotyrosine in the plasma of C3H and BALB/c mice and pharmacologically modulated their production during the acute phase of T. cruzi infection. We also looked for protein 3-nitrotyrosine in the hearts of infected animals. Our results demonstrated that C3H animals produced higher amounts of ÀNO than BALB/c mice, but their generation of peroxynitrite was not proportionally enhanced and they had higher parasitemias. While N G-nitro-arginine methyl ester treatment abolished ÀNO production and drastically augmented the parasitism, mercaptoethylguanidine and guanido-ethyl disulfide, at doses that moderately reduced the ÀNO and 3-nitrotyrosine levels, paradoxically diminished the parasitemia in both strains. Nitrated proteins were also demonstrated in myocardial cells of infected mice. These data suggest that the control of T. cruzi infection depends not only on the capacity to produce ÀNO, but also on its metabolic fate, including the generation of nitrating species that may constitute an important element in parasite resistance and collateral myocardial damage.

Tyrosinemia type I: a clinico-laboratory case report.

Progressive hepatocellular dysfunction in a neonate, resulting in elevated serum alpha-fetoprotein together with raised blood levels of tyrosine and methionine, a generalized amino aciduria and the absence of urinary delta-aminolevulinic acid and succinylacetone, suggests a diagnosis of tyrosinemia type Ib. Classical tyrosinemia type I arises from a deficiency of fumarylacetoacetate hydrolase while the variant tyrosinemia type Ib results from a deficiency of maleylacetoacetate isomerase.

Tryptophan and tyrosine catabolic pattern in neuropsychiatric disorders.

Catabolism of tryptophan and tyrosine in relation to the isoprenoid pathway was studied in neurological and psychiatric disorders. The concentration of trytophan, quinolinic acid, kynurenic acid, serotonin and 5-hydroxyindoleacetic acid was found to be higher in the plasma of patients with all these disorders; while that of tyrosine, dopamine, epinephrine and norepinephrine was lower. There was increase in free fatty acids and decrease in albumin (factors modulating tryptophan transport) in the plasma of these patients. Concentration of digoxin, a modulator of amino acid transport, and the activity of HMG CoA reductase, which synthesizes digoxin, were higher in these patients; while RBC membrane Na+-K+ ATPase activity showed a decrease. Concentration of plasma ubiquinone (part of which is synthesised from tyrosine) and magnesium was also lower in these patients. No morphine could be detected in the plasma of these patients except in MS. On the other hand, strychnine and nicotine were detectable. These results indicate hypercatabolism of tryptophan and hypocatabolism of tyrosine in these disorders, which could be a consequence of the modulating effect of hypothalamic digoxin on amino acid transport.

Endogenous strychnine, nicotine, and morphine--description of hypo and hyper-strychninergic, nicotinergic and morphinergic state in relation to neuropsychiatric diseases.

Previous work from this laboratory had demonstrated the presence of endogenous morphine, strychnine and nicotine in the mammalian brain and human serum samples. Morphine is synthesised from tyrosine and strychnine and nicotine from tryptophan. This study examines the role of strychnine, nicotine and morphine in neuropsychiatric disorders. The blood levels of tyrosine, tryptophan, strychnine, nicotine and morphine were studied as also RBC membrane Na(+)-K+ ATPase activity. It was found that serum tyrosine levels were reduced and tryptophan levels elevated in all neuropsychiatric disorders studied with a reduction in RBC Na(+)-K+ ATPase activity. Nicotine was present in significant amounts in serum of patients with schizophrenia, CNS glioma and syndrome X with multiple lacunar state. Morphine was present in significant amounts only in the serum of patients with multiple sclerosis and MDP. Strychnine was present in significant amounts in the serum of patients with epilepsy, Parkinson's disease and MDP. The presence of nicotine and strychnine in significant amounts could be related to elevated tryptophan levels suggesting the synthesis of these alkaloids from tryptophan. Morphine was not detected in most of the disorders owing to low tyrosine levels noted in them. Na(+)-K+ ATPase inhibition noticed in most of the disorders could be related to decreased hyperpolarising morphinergic transmission and increased depolarising nicotinergic and strychinergic transmission. The role of morphine, strychnine and nicotine in the pathogenesis of these disorders in the setting of membrane Na(+)-K+ ATPase inhibition is discussed.

Persistent tyrosinemia detected by thin-layer chromatography.

Screening for tyrosinemia is not routinely performed worldwide. Using a low expense thin-layer chromatography (TLC) for amino acids we detected a high frequency of transient tyrosinemia with secondary hyperphenylalaninemia in some newborns. Serum follow up showed the need to introduce adequate therapy in these babies.

Tyrosinaemia type II: an easily diagnosed metabolic disorder with a rewarding therapeutic response

We retrospectively reviewed clinical and biochemical data of four patients diagnosed with tyrosinaemia type II. Diagnosis was established by high plasma tyrosine and normal plasma phenylalanine levels using plasma high-pressure liquid chromatography and tandem mass spectrometry. All patients were mildly mentally retarded and had painful non-pruritic and hyperkeratotic plaques on the soles and palms. There were no ophthalmic symptoms. The patients dramatically responded clinically and biochemically to a diet restricted in tyrosine and phenylalanine

Tirosemia neonatal transitória: uma alteraçäo freqüente / Transient neonatal tyrosinemia: a frequent abnormality

Objetivos: Avaliar a freqüência da tirosinemia neonatal transitória, com ou sem hiperfenilalaninemia secundária, observada através da triagem neonatal para erros inatos do metabolismo ("teste do pezinho"), e a necessidade de monitoramento e eventual intervençäo medicamentosa o/ou dietética em casos específicos. Métodos: Foram analisadas 457.870 amostras de sangue seco obtido por punçäo de calcâneo de crianças de 3 a 20 dias de vida, através de cromatografia qualitativa de aminoácidos em camada delgada. Os casos positivos foram confirmados quantitativamente em amostras séricas pelas dosagens fluorimétricas da tirosina e da fenilalanina. Resultados: 1.231 amostras de sangue seco impregnado em papel filtro apresentaram resultados positivos para tirosina na avaliaçäo cromatográfica. A análise sérica por método fluorimétrico revelou valores normais de tirosina e fenilalanina em 822 pacientes; os restantes 409 apresentaram tirosina elevada e foram divididos em três grupos de acordo com a concentraçäo de tirosina observada. Em 118 destes pacientes foram observados também níveis de fenilalanina superiores ao limite de referência. Conclusöes: A tirosinemia neonatal transitória é um distúrbio muito freqüente em recém-nascidos (1/372), sendo que em alguns casos também säo registrados elevados níveis de fenilalanina. Enquanto näo estiver demonstrado que esse achado é completamente inócuo, o monitoramento desses pacientes e o eventual emprego de medidas que reduzem os níveis de tirosina e fenilalanina devem ser considerados pelo pediatra.

Hepatic phenylalanine-hydroxylase and tyrosine-aminotransferase mRNA levels in rats adapted to diets with different concentrations of protein

Se estudió el efecto de la concentración de la proteína de la dieta sobre concentraciones de ARNm de la tirosina aminotransferasa (TAT) y la fenilalanina hidroxilasa (PAH) hepáticas en ratas adaptadas a consumir dietas con 18 ó 50 por ciento de caseína en un horario restringido de 7 horas (9 a 16 h) durante 5 días. Las concentraciones de ARNm de TAT de ratas adaptadas a una dieta de 18 por ciento de caseína y alimentadas en forma aguda con dietas que contenían 6, 18 ó 50 por ciento de caseína, fueron 0.15, 0.84 y 5.08 veces más altas a las 6 horas en comparación con las concentraciones de ARNm antes de la administración de la dieta. Las concentraciones de ARNm de TAT después de 17 horas de ayuno en las ratas alimentadas con 6, 18 ó 50 por ciento de caseína fueron respectivamente -0.45, 1.76 y 9.11 veces mayores en comparación con el valor basal. Las concentraciones ARNm de PAH mostraron un patrón similar; en las ratas adaptadas a 18 por ciento de caseína se observó un aumento de -.68, 1.63 y 2.5 veces en las concentraciones de ARNm de PAH en las ratas alimentadas en forma aguda con 6, 18 y 50 por ciento de casína respectivmanete y un aumento de -0.86, 2.32 y 9.33 veces después de 17 horas de ayuno. La concentraciones de ARNm de TAT y PAH en ratas adaptadas a consumir 50 por ciento de caseína y luego alimentadas con 6 ó 50 por ciento de caseína mostraron un pico máximo a las 6 horas de ayuno. Estos resultados sugieren que las concentraciones crecientes de proteína en la dieta son capaces de producir aumentos en la concentración de los ARNm de las dos enzimas, posiblemente para eliminar el exceso de aminoácidos consumidos, ya que la concentración de los ARNm dependió más del contenido de proteína de la dieta de adaptación

Two cases of tyrosinemia type II and its rare occurrence in two brothers

Tyrosinemia type II is a rare autosomal recessive disorder which can present itself with recurrent epithelial keratitis, hyperkeratotic skin lesions and mental retardation. This article reports the rare occurrence of this disease in both offsprings [two brothers] of a family [consanguinous marriage] who were managed with a low protein diet and a special regimen

Separación de aminoácidos mediante cromatografía líquida de alta resolución / Amino acid analysis by high-performance liquid chromatography

Se presenta una compilación de la aplicación de la cromatografía líquida de alta resolución en el análisis de aminoácidos. Se analizan las formas de derivatización, se comparan los distintos derivados según sus alcances y limitaciones, la forma de detección y los distintos modos cromatográficos: cromatografía de intercambio iónico, cromatografía en fase normal, cromatografía en fase reversa y cromatografía en fase quiral. También se presentan los métodos automatizados comerciales más recientes para este tipo de análisis. Se dan ejemplos de aplicación de interés en el campo clínico-bioquímico, con el análisis de muestras de líquido cafalorraquídeo, de orina y de plasma/sangre o manchas de sangre seca. El análisis de los aminoácidos de hidrolizados de proteínas y de péptidos resulta más complejo y las condiciones de hidrólisis juegan un rol muy importante en los resultados, que son tratados en esta compilación. Se incluyen, además, aspectos referidos al análisis de los aminoácidos lábiles en proteínas, la preparación de las muestras, las recomendaciones prácticas al hacer HPLC y la influencia de los buffers