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Biomedical subjects

I Myara

Publications and source records attributed to I Myara.

At least 55 records · Page 3Linked to original sources
PubMed1989

Monitoring of heart allograft rejection by simultaneous measurement of serum beta 2-microglobulin and urinary neopterin.

In patients with heart transplant, the combined determination of serum beta 2-microglobulin and urinary neopterin, as rejection marker, prevented the interference by renal function and cyclosporin therapy. Unfortunately, the simultaneous measurement of these two parameters cannot distinguish between a rejection episode and the early stage of viral infection.

Biopterins↗
PubMed1989

Collagen biosynthesis anomalies in prolidase deficiency: effect of glycyl-L-proline on the degradation of newly synthesized collagen.

Prolidase deficiency is a rare hereditary disease characterized by an iminodipeptiduria especially composed by glycyl-L-proline which is not further degraded. The study of collagen metabolism in fibroblast cultures from three prolidase-deficient patients showed an increase in the rapidly degraded collagen and a decrease in the proline pool. In order to elucidate the mechanism of this metabolic disturbance, glycyl-L-proline was added to the cell cultures. In the control cultures, the addition of this dipeptide caused an increase in the rapidly degraded collagen and a decrease in the proline pool. The effects on the patient fibroblasts depended on the severity of the deficiency. The metabolic function of the dipeptide glycyl-L-proline was discussed in the light of these results.

Adult↗
PubMed1988

Plasma prolidase and prolinase activity in alcoholic liver disease.

Prolidase (EC 3.4.13.9) and prolinase (EC 3.4.13.8) activity was measured in the plasma of 53 patients with alcoholic liver disease. Plasma prolinase activity was not correlated with histological characteristics in liver biopsies. In contrast, prolidase activity rose significantly (p less than 0.02) in cirrhotic patients with alcoholic hepatitis in comparison with those without alcoholic hepatitis. It also showed a significant positive correlation with ASAT activity (r = 0.505, p less than 0.001) and with the ASAT/ALAT ratio (r = 0.452, p less than 0.001). Plasma prolidase activity did not allow the differentiation of patients with reversible fibrosis from those with cirrhosis. The interest of this new marker is discussed.

Adult↗
PubMed1988

Prolinase activity in prolidase-deficient fibroblasts.

The activity of prolinase (EC 3.4.13.8) was studied in cultured skin fibroblasts derived from three patients with deficient prolidase (EC 3.4.13.9). With pro-val as substrate and manganese in the reaction buffer, prolinase activity was higher in prolidase-deficient cells than in control cells (mean (SEM) 917 (67) nmol min-1 mg-1, n = 3, control mean (SEM) 294, (50), n = 11). The Michaelis constants were not different for the pro-val and progly substrates in control and prolidase deficient fibroblasts. However, the constants for Vmax rose for both substrates in deficient cells. These results demonstrate that prolinase activity increases in prolidase-deficient fibroblasts as also shown in the plasma of patients with prolidase deficiency. We suggest that in prolidase-deficient fibroblasts, this rise in prolinase activity constitutes an attempt to compensate for the prolidase deficiency by increasing the greatly reduced intracellular proline pool.

Adult↗
PubMed1987

Effect of long preincubation on the two forms of human erythrocyte prolidase.

The effect of prolonged preincubation for 24 h at 37 degrees C in the presence of 1 mmol/l manganese at pH 7.8 was investigated on the two forms of human erythrocyte prolidase after their separation by DEAE-Sephadex chromatography. Prolidase I activity, which was eluted in chromatographic fractions of low ionic strength of about 160 mmol/l NaCl, increased after preincubation and this activation was maintained throughout the subsequent steps of chromatofocusing, chromatography on Sephacryl S-200 in tandem with Blue-Sepharose, and Phenyl-Sepharose chromatography. It disappeared after the last step consisting of a second Blue-Sepharose chromatography. When the protein environment was restored, isolated prolidase I was reactivated by preincubation, and as a result, gly-pro procollagen dipeptide became the best substrate. Gly-pro-hyp procollagen tripeptide was also observed to have a strong activator effect. The activity of prolidase II, which was eluted in high ionic strength fractions of about 260 mmol/l NaCl during DEAE-Sephadex chromatography, diminished markedly after preincubation and was very low against the gly-pro substrate. These results seem to indicate that prolidase I is much more active than prolidase II in the intracellular degradation of procollagen.

Blood Specimen Collection↗
PubMed1987

Metabolic studies of a sustained galactose overload in rat.

In order to obtain an experimental model for studying inherited disorders of galactose metabolism in man, we administered to adult rats a diet supplemented with 50% of galactose during 38 days. The results showed clinical symptoms such as polyuria, polydipsia, growth retardation and bilateral cataract. The main biochemical features were an increase in the galactokinase and uridyltransferase activities in liver, an ubiquitous accumulation in tissues and a considerable urinary elimination of galactose and galactitol, a weak accumulation of galactose-1-phosphate in tissue and a hyperaminoaciduria. This work led us to quantify the respective importance of the major pathway and minor pathways of galactose in the rat after a galactose-rich diet.

Animals↗
PubMed1987

Changes in prolinase and prolidase activity during CCl4 administration inducing liver cytolysis and fibrosis in rat.

In earlier papers, we reported that the activity of prolidase (EC 3.4.13.9) increased in the plasma of patients with cirrhosis, while that of serum prolinase (EC 3.4.13.8) was normal and was affected only by necrosis. In this work, we investigated prolinase and prolidase activity during short and long-term CCL4 administration in the rat. After a single dose, prolinase activity increased in serum faster than did prolidase activity and it also decreased more slowly. Within the liver, no significant change in these two enzyme activities was observed during the acute phase of necrosis. During chronic CCl4 intoxication, the rises in prolidase and prolinase activity in rat serum were difficult to interpret, because of the liver necrosis present throughout the experiment. However, within the liver, prolinase activity was not affected, unlike that of prolidase which rose at week 3, reached a maximum value at week 6 (reversible fibrosis) and remained elevated at weeks 10 and 12 (irreversible fibrosis). The increase in prolidase activity was specific for liver and was not observed in other tissues. These results are in agreement with those obtained in humans; they highlight the possible physiological significance of enhanced liver prolidase activity during the fibrotic process.

Alanine Transaminase↗