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Biomedical subjects

M Pizzichini

Publications and source records attributed to M Pizzichini.

At least 73 records · Page 4Linked to original sources
PubMed1991

Some aspects of purine nucleotide metabolism in lymphocytes of B-CLL.

The authors studied the behavior of some enzymes involved in purine nucleotide metabolism in human peripheral blood lymphocytes from normal and B-cell chronic lymphocytic leukemia subjects. Determinations were made with radiochemical methods associated with high performance liquid chromatography. Results indicated a marked increase in de novo purine synthesis enzymes, particularly those of the "inosinic branch point". The latter were absent in normal lymphocytes, whereas they were well evident in leukemic lymphocytes, with the exception of AMP-S synthetase. Whereas the enzymes of the "salvage pathway" were spared in comparison to other proteins, those of the "catabolic pathway" significantly decreased. The authors discuss the possibility that such enzymes may be used as tumor markers.

AMP Deaminase↗
PubMed1991

Effects of testosterone on the liver of castrated rats: morphologic study.

It is well known that castration in rats causes atrophy of the sexual organs and, to a lesser extent, of other organs. We have observed that castration causes a reduction of the liver weight due to a reduction (-10%) of the numerical density of the hepatocytes after castration (p less than 0.01). Testosterone administration at high concentration (2.5 mg/100 g b. wt.) as well as at low concentration (0.025 mg/100 g) in the castrated rats causes an increase of the liver weight due to an increase (+30%) in the cellular area (p less than 0.001) as well as in the nuclear area (+20%) (p less than 0.01) of the hepatocytes, revealing a powerful hypertrophic effect of the hormone in the liver.

Animals↗
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

Influence of testosterone on purine nucleotide turnover in rat kidney.

The influence of testosterone on purine nucleotide metabolism in rat kidney has been investigated in adult and in prepubertal castrated rats. Results have been evaluated through biomathematical model. Castration enhanced the turnover of purine nucleotides in adult rats and reduced it in young castrated rats. Treatment with testosterone in the castrated rats further enhanced nucleotide turnover both in the adult rats and also in the second group, with an oscillatory profile. A clear effect on the inosinic branch point was demonstrated, and specifically on GMP formation, which was opposite according to the age of the animal. The different behavior in the two groups after castration was partially ascribed to the action of other hormones in the absence of testosterone. The observed changes show that the action of the hormone is not limited to sexual organs; they might be at the basis of variations in cellular size and number which probably occur in the kidney after orchiectomy and following androgen administration.

Animals↗
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↗