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Biomedical subjects

C Costa

Publications and source records attributed to C Costa.

At least 253 records · Page 14Linked to original sources
PubMedDate not supplied

[Acquired renal cystic disease in uremia: a prevalence survey].

The acquired cystic disease of the kidney (ACDK) occurs in uremic patients before and during dialysis treatment. It has been defined as a disease with multiple acquired cystic lesions in patients with advanced renal failure. We evaluated its prevalence in a group of 94 uremic patients employing ultrasonographic examinations. Eighteen patients were not on dialysis treatment (group I) and 76 patients were undergoing hemodialytic treatment (group II). The prevalence of ACDK in groups I and II was 16.7% and 39.5% respectively. There is a noteworthy progression in the prevalence of the disease as the patients are kept alive by dialysis treatment. Primary renal disease, age and sex were not important factors in the disease's prevalence.

Adult↗
PubMedDate not supplied

Effects of two different loading doses of L-tryptophan on the urinary excretion of tryptophan metabolites in rats, mice and guinea pigs. Correlation with the enzyme activities.

The effect of two different loading doses of L-tryptophan (0.5 and 1.0 g/Kg b.w.) on excretion of tryptophan metabolites and the relation to the enzyme activities were studied in rats, mice and guinea pigs. In rats there is no ratio between the dosage used and the levels of the metabolites excreted. Doubling the amount of tryptophan administered, a 5-fold increase in the elimination of the metabolites along the kynurenine pathway is obtained. The 1.0 g/Kg load provides a more complete pattern of the metabolites than with the 0.5 g/Kg b.w. load. Kynurenic acid, kynurenine and xanthurenic acid are the chief metabolites excreted. In mice, the urinary excretion of the metabolites is very low with both loads. In guinea pigs, xanthurenic acid is excreted in the highest amount and kynurenic acid and kynurenine also constitute the large fractions with both loadings. The load of 0.5 g/Kg b.w. is preferable to that of 1.0 g/Kg b.w. for not causing B6-deficiency. Liver tryptophan pyrrolase exists in two forms in rats, while in mice and in guinea pigs it is present only as holoenzyme. This enzyme is more active in rats than in the other two species of animals. Kynureninase activity is lower in guinea pigs, but it apparently correlated to the low levels of excretion of the metabolites following this step. Kynurenine aminotransferase is very active in rats and in mice, while it is apparently depressed in guinea pigs, in contrast with the high excretion of xanthurenic and kynurenic acids, that puts in evidence a B6-deficiency. The excretion of tryptophan metabolites and enzyme activities are better correlated in rats.

Animals↗
PubMedDate not supplied

[Methodological indications for the experimental study of the action of disinfectants on bacterial strains].

The most commonly used techniques for the experimental study of the action of disinfectants with respect to bacterial strains (M.I.C. and B.M.C. determination, phenol coefficient, well test, agar diffusion through plates test, transporter test, contact by suspension test) are reviewed. The methods used personally in numerous experiments, the modified contact test, is then described in detail.

Bacteria↗
PubMedDate not supplied

Metabolites and enzyme activities involved in tryptophan metabolism in two different strains of mouse.

The urinary excretion of the tryptophan metabolites along the kynurenine pathway and the variations of enzyme activities involved in the degradation of tryptophan have been studied in two strains of mice. The total excretion of the metabolites was significantly higher in the strain of albino N.C.L. than in Swiss albino mice, in accordance with the higher activity of tryptophan pyrrolase, which was present only as holoenzyme. In both strains kynurenine, kynurenic and xanthurenic acids were excreted in larger amounts. However, the albino N.C.L. mice excreted a large amount of xanthurenic acid, not correlated with the slightly higher kynurenine aminotransferase activity observed in this strain. The very high excretion of this metabolite indicates that the load of tryptophan causes a B6-deficiency. Liver kynureninase activity was similar in both strains. Correlation between total urinary excretion of the tryptophan metabolites and enzyme activities appears in the same strain of mice, even though differences are present in different strains.

Animals↗
PubMedDate not supplied

Strain differences in the tryptophan metabolite excretion and enzyme activities along the kynurenine pathway in rats.

The strain differences of the urinary excretion of the tryptophan metabolites along the kynurenine pathway and the variations of enzyme activities metabolizing the tryptophan have been studied in different strains of rats. There is a good correlation between urinary excretory values of the metabolites and enzyme activities in the same strain of rats. However, some differences appear when the data are compared among different strains. Wistar, heterozygous Gunn and Sprague-Dawley rats show similar total urinary excretion of tryptophan metabolites, while the Long Evans rats have significantly lower values, in accordance with the lower activity of tryptophan pyrrolase. Kynureninase activity is slightly but not significantly higher in Sprague-Dawley rats, in agreement with the high levels of anthranilic acid excreted. As regards kynurenine aminotransferase, Sprague-Dawley rats show lower activity in the liver, but higher activity in the kidneys in comparison to other strains of Wistar, Long Evans and heterozygous Gunn rats. The importance of considering strain differences is emphasized when making comparisons of measurements carried out in different laboratories.

Animals↗
PubMedDate not supplied

[Heterogeneity of antimicrosomal autoantibodies in chronic hepatitis C virus infection and delta hepatitis].

Microsomal antigen autoantibodies are typical of type 2 autoimmune hepatitis, and a strong association with chronic hepatitis C virus (HCV) infection has been reported in certain geographical areas. These autoantibodies have been denominated LKM-1 to differentiate them from those associated with thienylic acid-induced hepatitis (LKM-2) and from those seen in patients with chronic delta hepatitis (LKM-3). To investigate the antigenic specificity of autoantibodies associated with chronic hepatitis C and delta, we analyzed 52 LKM-1 positive serum samples from patients with chronic hepatitis C and 17 LKM-3 positive serum samples from patients with chronic delta hepatitis by indirect immunofluorescence and Western blotting (immunoblotting). Reactivity of subjects with chronic hepatitis C was heterogeneous: only 5 out of 52 LKM-1 positive patients, tested by Western blot, recognized a single protein of 50 kD, previously identified by Manns et al. with an immunogenic epitope of cytochrome P450IID6. Thirteen of the 52 patients also reacted with a 70 kD microsomal protein, and 12 out of 52 reacted only with a 59 kD protein. Twenty-two sera, notwithstanding the high titer in immunofluorescence, did not evidence any reactivity when tested by Western blot. The same sera tested positive in LKM-1 ELISA when solubilized human microsomal proteins were used. Fourteen out of 17 LKM-3 positive sera from patients with chronic hepatitis delta recognized a 55 kD microsomal protein in Western blot; three sera, HCV and HIV positive, did not react with any protein by Western blot. None of these sera was positive in ELISA LKM-1.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibody Specificity↗