Biomedical subjects
Publications and source records attributed to S Ferrari.
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The effect of oral clonidine on prothrombin time, partial thromboplastin time, blood fibrinogen, fibrinolytic activity and platelet count was investigated in 25 hypertensive and 7 normal subjects. High plasma fibrinogen levels were present in 80% of the hypertensive patients and prolonged lysis time in 28%; the means values were 487 +/- 135 mg % and 223 +/- 62 min., respectively. The other coagulation tests were normal. 0,300-0,450 mg/day clonidine per os for 15 days both decreased fibginogen levels (mean 406 +/- 149; p less than 0.05) and shortened lysis time (mean 153 +/- 78 min; p less than 0.005). No changes were noted in the normal subjects. The pathophysiological mechanism of these findings is discussed and their possible implications for the treatment of hypertension are emphasised.
45S ribosomal precursor RNA and large heterogeneous RNA molecules (greater than 45S) extracted from human leukemic cells were incubated in vitro with purified RNase III, which specifically attacks double-helical RNA regions. About 50% of the ribosomal precursor was cleaved into two major fragments sedimenting at 28S and 32S respectively. A limited number of cleavages was also introduced in about 40% of heterogeneous RNA molecules sedimenting faster than 45S, causing a partial 'shift' to a polydisperse distribution in the 10S-45S range.
Whole-cell RNA, extracted from acute myeloid leukemia blast cells, was fractionated by sedimentation through sucrose gradients. The proportion of double-helical segments present in each fraction was then determined by a quantitative microcomplement fixation assay that specifically measures double-helical RNA. Sizable amounts of double-helical segments were detected in all fractions of cellular RNA corresponding to S values higher than approximately 20. In all cell populations examined the highest proportion of double-helical segments was found in RNA fractions sedimenting faster then the 45 S ribosomal precursors RNA, i.e., in fractions including only heterogeneous nuclear RNA.
Ribonuclease activity directed against the synthetic duplex polyrC:polyI was detected in nuclear extracts from both unstimulated and PHA-stimulated human lymphocytes. In the latter cells, the activity was about twice that of small lymphocytes.
Time course and "chase" experiments showed that, after incubation of acute myeloid leukemia blast cells with a labeled RNA precursor, a large proportion of radioactivity remained associated with RNA molecules larger than 45 S even after several hr. Double-labeling experiments with [5-3H]uridine and [methyl-14C]methionine indicated that unmethylated giant heterogeneous RNA larger than 45 S is processed much more slowly than the 45 S ribosomal precursor, so that relatively large amounts of fairly stable RNA of the former class accumulate in the cell. The measurement of labeled giant heterogeneous RNA molecules bound to polyuridylate-fiberglass filters showed that molecules carrying polyadenylate segments seemingly turn over faster than those lacking polyadenylate.
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Cholesterol/phospholipids molar ratio and fatty acid composition have been estimated in erythrocyte membrane of 12 patients suffering from nephrotic syndrome and compared to values obtained in 23 normal subjects matched for sex and age. The membrane lipid composition has been correlated with the activity of erythrocyte Li-Na countertransport of the same subjects. The results show a significant increase in cholesterol/phospholipids ratio and total saturated fatty acids when erythrocytes of nephrotic patients are compared to normal erythrocytes, whereas total unsaturated fatty acids were lower in nephrotics (p less than 0.002). Li-Na countertransport was higher in nephrotics (p less than 0.001) and it was positively correlated with the total amount of saturated fatty acids of the erythrocyte membrane (r = +0.451; p less than 0.01). On the contrary, Li-Na countertransport was negatively correlated with the total amount of unsaturated fatty acids (r = -0.468; p less than 0.01).
Total cholesterol (TC), triglycerides (TG), and lipoproteins (by electrophoresis on agarose gel) were determined in the cord blood of 124 Italian infants (Verona area). The mean TC and TG values, when compared with the values reported in other studies, turned out to be remarkably uniform, suggesting common genetic determinants in the modulation of blood lipids; no sex differences were observed. The TG distribution curve was skewed, overlapping the adult pattern. Cord blood TC and TG were not modified by the presence of perinatal factors. Both beta and alpha bands (on agarose gel electrophoresis) were present in all the cases. The pre-beta band was clearly detectable in 90% of the cases; it was barely visible for TG values below 20 mg/100 ml; occasionally a discrepancy between the intensity of the pre-beta band and the cord blood TG was observed, indicating a variable lipid composition of very low density lipoproteins (VLDL). In 4% of the cases a small band at the origin of the electrophoretic run was observed, consistent with the presence of chylomicrons. In the serum of both a newborn infant and its mother we detected a double band migrating in the pre-beta region. This finding confirms the hypothesis of a familial transmission of this abnormality.
The fatty acid composition of erythrocyte membrane, the glutathione-peroxidase activity of erythrocytes and platelets, the production of malondialdehyde by platelets and the activity of the main systems of transmembrane cation transport have been studied in 5 members of a family, 2 of whom affected by Laurence-Moon-Barter-Biedl Syndrome. A remarkable increase of polyunsaturated fatty acids (particularly arachidonic acid) and of cholesterol/phospholipid molar ratio has been noted. This pattern of membrane lipids was associated to an increment of malondialdehyde production and an increase activity of glutathione-peroxidase. Serum retinol and a-tocopherol were in the normal range, whereas serum selenium was low in 3 out of 5 members. Moreover, the alteration of membrane lipids was associated to a decrease of the maximal velocity of Li-Na countertransport. We speculate that the enrichment of polyunsaturated fatty acids on the cell membranes may represent a condition favoring the lipoperoxidation and therefore the development of the retinitis pigmentosa characteristic feature of Laurence-Moon-Barter-Biedl Syndrome.