Cuantificación de cistina en orina espontánea para la detección de cistinuria / Quantitation of urinary cystine for the detection of cystinuria / Determinagáo quantitativa de cistina urinaria para a detecgáo de cistinuria

La cistinuria es un error innato del metabolismo ocasionado por un defecto en el transporte renal de arginina, ornitina, lisina y cistina. La acumulación de este último aminoácido de baja solubilidad ocasiona episodios de urolitiasis característicos de la enfermedad. En el presente estudio se estandarizó un método espectrofotométrico confiable y de fácil ejecución para la determinación cuantitativa de cistina en orina espontánea. Se realizó el análisis en 184 muestras, correspondientes a 104 controles y 80 pacientes con urolitiasis. Con el objeto de validar el método y posteriormente establecer un rango de excreción normal en la población colombiana se evaluaron los siguientes parámetros: exactitud, precisión, linealidad y límite de detección. La técnica mostró coeficientes de variación intra e inter ensayos inferiores al 10% y una excelente linealidad, con un coeficiente r² entre concentraciones conocidas de cistina y absorbancia generada por el método de 0,998. Usando esta técnica se encontró un valor normal de excreción de 1,35 a 110,11 mg cistina/g creatinina. En cinco pacientes, de los 80 con nefrolitiasis, se hallaron valores elevados de cistina, compatibles con cistinuria. El método utilizado puede implementarse en cualquier laboratorio clínico para confirmar el diagnóstico de cistinuria e iniciar un tratamiento oportuno.

Cystinuria is an inborn error of metabolism, caused by a defect in renal tubular transport of the following aminoacids: arginine, ornithine, lysine and cystine. Accumulation of the latter poorly soluble aminoacid leads to the development of kidney stones, characteristic of the disease. In this study, an easy and dependable spectrophotometric method for the quantitative determination of urinary cystine was standardized. The analysis was performed on 184 samples from 104 controls and 80 patients with kidney stones. In order to validate the method and later establish a range of normal urinary cystine excretion in the Colombian population, the following parameters were evaluated: Accuracy, precision, linearity and lower limit of detection. The technique showed intra and intei assay coefficients of variation below 10%, and excellent linearity, with an R square (r²) coefficient between known cystine concentrations and absorbance generated by the method at 0.998. Using this technique, a normal urinary cystine excretion range of 1.35-110.11 mg cystine/g creatinine was found. Among the 80 patients with kidney stones, elevated urinary cystine levels were found in 5 of them, compatible with the presence of cystinuria. This method can be implemented in any clinical laboratory to confirm the diagnosis of cystinuria and provide opportune treatment.

A cistinúria é um erro inato do metabolismo, causado por um defeito no transporte tubular renal de ar-ginina, ornitina, lisina e cistina. A acumulagáo deste último aminoácido, pouco solúvel, provoca episodios de urolitíase, característicos da doenga. No presente estudo, foi padronizado um método espectrofotomé-trico confiável e de fácil execugáo para a determinagáo quantitativa de cistina em urina espontánea. A análise foi realizada em 184 amostras de 104 controles e 80 pacientes com urolitíase. A fim de validar o método e, posteriormente, estabelecer um intervalo de excregao normal na populagao colombiana, foram avaliados os seguintes parámetros: exatidáo, precisáo, linearidade e limite inferior de detecgáo. O método mostrou coeficientes de variagáo intra e inter ensaios inferiores a 10%, e excelente linearidade, com um coeficiente R quadrado (r²) entre concentragoes conhecidas de cistina e absorváncia gerada pelo método de 0,998. Com esta técnica, foi encontrado um valor normal de excregáo de 1,35-110,11 mg cistina/g de creatinina. Entre os 80 pacientes com urolitíase, foram encontrados níveis elevados de cistina em cinco deles, compatíveis com a presenga de cistinúria. Este método pode ser implementado em qualquer laboratorio clínico para confirmar o diagnóstico de cistinúria e proporcionar um tratamento oportuno.

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.

Protein and plasma amino acid metabolism in cancer patients

Proteins present in the human body have numerous functions. Amino acids are the building blocks of proteins used for structural and regulatory functions of body. In cancer cachexia the patients develop anorexia, diminished intake of calories with significant abnormalities in carbohydrate, lipid and protein metabolism and progressive tissue depletion accompanied by weight loss. The gradual loss of host protein stores is central to this process which leads to amino acid imbalance in the blood and some times decreased levels of certain amino acids. Increased urinary amino acids occur in patients of certain cancers. These changes in the amino acid result into altered host defence against cancer and also the therapeutic complications in these patients. Extra nutritional support through gut and total parenteral nutrition [TPN] can alter the tumour host nutrition balance and repletion occur

Aminoacidos urinarios: electroforesis por alto voltaje y acetato de celulosa gelatinizado / Urinary amino acids: electrophoresis for high voltage and in gelatinized cellulose acetate

El estudio de las alteraciones del metabolismo de los aminoacidos urinarios ha motivado el desarrollo de dos tecnicas simples, rapidas y economicas, para el uso en Quimica clinica. Se describe la celda electroforetica disenada, asi como todas las operaciones requeridas para lograr dicho objetivo (tratamiento de los soportes usados y de las muestras, buffers, condiciones de corrida, distintos metodos y reactivos de revelado, desintometria). Se comparan los resultados obtenidos para los soportes empleados, papel y acetato de celulosa gelatinizado, usando para ambos igual sistema de refrigeracion y los resultados obtenidos en comparacion con otra forma de enfriamiento del sistema, utilizada previamente. Tambien se discute la aplicacion de mayores voltajes y la importancia de la estandarizacion en la coloracion. Trabajando con acetato de celulosa gelatinizado se pueden valorar por densitometria las corridas, lo cual brinda una util herramienta a los laboratorios clinicos

Aminoaciduria: a possible marker of renal tubular damage in children with collagen vascular disease [CVD]

Forty seven children with CVD and fifty age and sex matched controls was studied. Careful clinical evaluation and laboratory investigations were carried out to both cases and controls. C reactive protein [CRP] and rheumatoid factor [by latex] were unsuitable for diagnosing [CVD]. Antinuclear antibodies [ANA] were highly positive among SLE group versus the other groups and controls. However ANA-ve SEL, cases were also found. Anti-ds DNA antibodies were highly specific for SEL. 68.1% of CVD patients had renal involvement whether in the form of an abnormal urinary sediment or elevated serum urea and creatinine. Most had an abnormal urinary amino-gram. In some cases an elevated urinary amino-aciduria was the only evidence of renal affection. Proteinuria correlated positively with amino-aciduria

Síndrome de Borjeson-Forssman-Lehmann: relato de um caso / Borjeson-Forssman-Lehmann syndrome: report of a case

Apresentamos um caso de síndrome de Börjeson-Forssman-Lehmann, caracterizado pela presença de hipogonadismo, aparência facial grotesca, microcefalia, orelhas grandes, obesidade e convulsöes. Além desses achados, comuns aos demais casos descritos na literatura, o paciente apresentava hiperglicemia e aminoacidúria. Assim, concluímos que a presença dessas alteraçöes e a má evoluçäo do caso, com morte ainda no primeiro ano de vida, contribuem para ampliar o espectro fenotípico da síndrome de Börjeson-Forssman-Lehmann

study of plasma amino acid pattern in patients with Schistosomal hepatic fibrosis

This study was carried out on thirty patients with Schistosomal hepatic fibrosis and ten non Schistosomal normal control. The results obtained showed, that there was a significant - increase in 3 plasma amino acids, methionine, phenyl alamine and tyrosine in the ascitics, and a significant rise in plasma methionine in the bleeders. All the Schistosomal cases showed a significant amino-aciduria. The significance of these changes are discussed