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Biomedical subjects

B Porcelli

Publications and source records attributed to B Porcelli.

48 records · Page 3Linked to original sources
PubMed1990

Plasma oxypurines in gastric and colorectal cancer.

Reverse phase high performance liquid chromatography has been used for the determination of plasma hypoxanthine, xanthine, and uric acid in normal subjects and in patients with gastric and colorectal cancer. Plasma oxypurines are significantly elevated in either type of cancer, while uric acid concentration is only higher in gastric cancer. The variations are related to the stage of the tumors, and the physiopathology of their occurrence is discussed.

Adenocarcinoma↗
PubMed1990

[Enzymes of the inosinic crossing point in human lymphocytes].

At the "inosinic branch point", inosinic acid (IMP) can be channelled either to guanylic acid (GMP) or to adenylic acid (AMP). The 4 enzymes involved in these processes are IMP-dehydrogenase (IMP-DH) and GMP synthetase for the formation of GMP and adenylosuccinate (AMP-S) synthetase and lyase for the formation of AMP. The Authors study the behavior of these enzymes in peripheral blood lymphocytes from normal and leukemic patients. The cells were isolated as previously reported. GMP synthetase was assayed with radiochemical method, IMP-DH and AMP-S synthetase with a radiochemical method coupled to HPLC, while AMP-S lyase was determined following the formation of AMP separated by AMP-S by HPLC, without using labelled precursors. Except for GMP synthetase, which was very low, no activity was detectable in normal lymphocytes; while AMP-S was absent also in leukemic cells, the remaining three activities were well evident. The results open the possibility of using the inosinic branch point enzymes as tumor markers.

Adenylosuccinate Lyase↗
PubMed1990

[Behavior of the enzymes of the salvage pathway of purine bases in leukemia lymphocytes].

The Authors present a procedure for the determination of adenine phosphoribosyltransferase (APRT) and hypoxanthine phosphoribosyltransferase (HPRT) in lymphocytes which exhibits high sensitivity and requires low quantities of lymphocytes. 5 normal subjects and 4 patients affected by chronic lymphocytic leukemia (CLL) were considered. Human lymphocytes were prepared and treated as previously reported. To the incubation mixtures buffered with 50 mM TRIS-HCl pH 7.4 either 14C-adenine or 14C-hypoxanthine was added: after deproteinization and neutralization we followed the formation of either 14C-adenylic acid (AMP) or 14C-inosinic acid (IMP) by HPLC. A Supelcosil C18 5 microns (250 X 4.5 mm) column was used: IMP was eluted with 20 mM KH2PO4 pH 5.5 while AMP with a linear gradient to 40% B in 20 min., where A was 20 mM KH2PO4 pH 5.5 and B methanol/water 60:40. Evaluation of AMP and IMP formed was carried out by determination of the radioactivity of the collected peaks. The values of APRT in leukemic patients were enhanced when referred to the proteins and those of HGPRT decreased: the Authors propose to complete the study evaluating the intracellular content of adenine and hypoxanthine.

Adenine Phosphoribosyltransferase↗
PubMed1989

The excretion of oxypurines in normal subjects.

Reverse phase high performance liquid chromatography was used for the determination of urinary hypoxanthine and xanthine in normal subjects. The values observed in normal subjects agree with those reported by other authors. Excretion of hypoxanthine and xanthine was not related to sex. Urinary oxypurines were related to age, and, when corrected for body surface area (1.73 m2), they were significantly higher in normal children under 15 years of age than in adults.

Adolescent↗
PubMed1989

[Analysis of uric acid and oxypurines in normal subjects and in gout patients].

The behavior of plasma and urine oxypurines (hypoxanthine and xanthine) and of uric acid has been studied in normal subjects and in gout patients. Oxypurines and uric acid were increased in the plasma of gout patients but only the urinary excretion of hypoxanthine was higher in this group. The interpretation of the observed variations is discussed.

Adult↗
PubMed1989

[Clearance of oxypurines in normal subjects and in gout patients subjected to a purine-free diet. Effects of allopurinol].

The clearance of uric acid, hypoxanthine and xanthine has been examined in gout patients and in normal subjects compared to creatinine, after a purine-free diet. The treatment decreased the clearance in normal subjects, but showed an opposite effect in gout patients. The clearances both of uric acid, hypoxanthine and xanthine were enhanced by allopurinol. The interpretation of the observed variations is discussed.

Adult↗
PubMedDate not supplied

Purine bases and atheromatous plaque.

In this work we determined hypoxanthine (HX), xanthine (X), uric acid (UA), allantoin (ALL) and free radicals in atheromatous plaques to improve the comprehension of oxidative stress, a phenomenon which characterizes the evolution of atherosclerotic lesions. Carotid artery plaque were obtained from subjects undergoing endoarterectomy. Pulverized plaque, extracted by water, was used for analysis of oxidative stress factors (allantoin, uric acid, xanthine, hypoxanthine, free radicals). The peroxidation UA-->ALL was very high in the plaque, as was the level of free radicals. The results show that oxidative degradation of nucleotides, such as LDL oxidation, plays a specific role not only in the progression of atherosclerotic lesions but also in the advanced plaque.

Allantoin↗
PubMedDate not supplied

[Behavior of plasma and urine purines, after a purine-free diet, in normal subjects and patients with gout].

Plasma and urine oxypurines (hypoxanthine and xanthine) and uric acid, were evaluated in normal subjects and in gouty patients before and after a purine free diet. After a 7-days period, plasma oxypurines were remarkably higher in normal subjects, while they did not undergo variations in gouty patients, which showed higher in basal conditions. No significant changes in urinary excretion were observed in both cases. The interpretation of the observed variations is discussed.

Adult↗
PubMedDate not supplied

[Clearance of oxypurines and uric acid in patients with gout].

The clearance of uric acid, hypoxanthine and xanthine has been examined in gouty patients and in normal subjects comparatively to the creatinine clearance. The clearance of the three purine compounds was lower in the gouty patients, while the creatinine clearance showed a normal behavior. These results indicate that either the tubular excretion or the carriers of the considered metabolites probably undergo specific alterations in the gout.

Adult↗
PubMedDate not supplied

[Purine metabolism in human tumors].

Levels of oxypurines (hypoxanthine and xanthine) and uric acid were measured in plasma and urine of tumor bearing patients (gastric and colon rectal tumors), and of subjects affected by non specific diseases. In both groups, an increase in plasma purine bases and a decrease of their excretion was observed as compared to healthy controls; no substantial variations concerning uric acid were found. Possible mechanisms inducing alterations of purine metabolism in so different conditions are discussed.

Biomarkers, Tumor↗