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Biomedical subjects

A Angelini

Publications and source records attributed to A Angelini.

At least 127 records · Page 7Linked to original sources
PubMed1985

Biochemical characterization of ventricular myosin from spontaneously hypertensive turkeys.

Several stimuli are able to alter the synthesis of cardiac myosin isoenzymes. Particularly in the rat a shift toward a low-ATPase isomyosin is generally observed during development and in cardiac hypertrophy due to pressure overload. On the contrary in spontaneously hypertensive turkeys both ageing and the increasing degree of cardiac hypertrophy are accompanied by a different behaviour of ventricular myosin. In fact in a previous study we have shown that the Ca2+-activated ATPase activity of ventricular myosin increases about three folds from young normotensive to old hypertensive animals. Accordingly the peptide pattern obtained after chymotryptic digestion of myosin showed that some peptides, which are not evident or barely discernible in young animals, are present in the adult ones. In this study we compare the ventricular myosin from young normotensive and adult hypertensive turkeys with atrial myosin. The results obtained suggest that in the ventricles of hypertensive turkeys the synthesis of an isomyosin with biochemical properties close to those of atrial myosin occurs.

Adenosine Triphosphatases↗
PubMed1985

Evidence of reduced atherosclerotic lesions in broad breasted white turkeys treated with oxprenolol.

Male Broad Breasted White Turkeys (BBWT) are naturally hypertensive and prone to develop atherosclerosis. Hypertension is characterized by high levels of circulating and tissue catecholamines; atherosclerosis affects mainly the aorto-iliac tract. To evaluate the effect of a beta-blocker on both hypertension and atherosclerosis, 2 groups of BBWT were studied. First group: 12 BBWT treated from the 8th week of age with daily p.o. placebo; second group: 6BBWT treated from the 8th week with 2 mg/kg p.o. daily oxprenolol. Blood pressure (BP) and heart rate (HR) were periodically measured with an indirect method. Seven and 5 BBWT of the first group were sacrificed at 24 and 51 weeks respectively. The 6 animals of the second group were sacrificed at 51 weeks. No significant difference in mean BP and HR values was found between the two groups of animals. On the contrary the oxprenolol treated group displayed a significant reduction in extent and severity of the atherosclerotic lesions. These results seem to substantiate that oxprenolol might positively interfere with the setting of atherosclerosis in these animals independently of BP reduction. One possible explanation could be a direct effect of oxprenolol on the arterial wall.

Aging↗
PubMed1983

[Evaluation of the efficacy of various hypotensive drugs in broad-breasted white turkeys as an experimental model of arterial hypertension with high catecholamine levels].

Male Broad Breasted White Turkeys (BBWT) represent an experimental model of arterial hypertension characterized by high levels of circulating and tissue catecholamines. We thought interesting to evaluate the efficacy of the long term treatment with different antihypertensive drugs. 59 male BBWT were studied, divided in five groups. The first group (13 animals) was treated with placebo; the second (14 animals) with oxprenolol 4 mg/Kg/q.d.; the third (10 animals) with labetalol 25 mg/Kg/q.d.; the fourth (11 animals) with verapamil 15 mg/Kg/ q.d.; the fifth (11 animals) with captopril 8 mg/Kg/ q.d. and furosemide 2,5 mg/Kg/q.d. All drugs were given p.o, from the 8th to the 33rd week of age. Weekly or every two weeks Blood Pressure (BP) and Heart Rate (HR) were measured by an indirect method. In all animals BP progressively increased and HR progressively decreased with age. Only the labetalol-treated animals showed a significant reduction of BP and HR through the study period as compared with the placebo-treated animals. These results confirm the preminent role played by the high levels of circulating catecholamines in determining and maintaining the arterial hypertension.

Animals↗
PubMed1982

The in vitro effect of a calf thymus extract (thymostimulin) on T cell phenotypes in cord blood lymphocytes.

An investigation was carried out on the in vitro effect of a calf thymus extract, thymostimulin, on the distribution of T cell phenotypes as defined by OKT3, OKT4, and OKT8 murine monoclonal antibodies and on E-rosetting cells in human cord blood lymphocytes from healthy newborns. The percentages of E-rosette-forming lymphocytes and OKT3+ total T population were lower in newborns than in adults (E-rosettes: 43.8% +/- 13% vs 57.9% +/- 7.9%, p less than 0.01; OKT3+ cells: 53.3% +/- 15.5% vs 79.9% +/- 4.7%, p less than 0.01), while the OKT4+/OKT8+ (helper/suppressor) cell ratio was normal in both (newborns: 3.40; adults: 2.44-NS). Thymostimulin increased the number of E-rosette-forming cells from 43.8% +/- 13% to 49.9% +/- 12.7% (p less than 0.01), as well as the percentage of phenotypic T lymphocytes. The highest increases were observed in the OKT4+ cells (37.7% +/- 14% to 49.1% +/- 13.8%, p less than 0.001), while smaller changes were observed in the OKT3+ cells (53.3% +/- 15.5% to 58.1% +/- 13.3%, p less than 0.02) and OKT8+ cells (12.8% +/- 6.4% to 16.6% +/- 6.5%, p less than 0.02). The results of the present study suggest that thymostimulin mainly provokes an increase in the helper T cell phenotype in cord blood lymphocytes.

Antigens, Surface↗
PubMed1981

Rapid test on amniotic fluid for diagnosis of foetal pulmonary maturity.

The Authors have carried out a study on samples of amniotic fluid taken at various gestational ages. They compare the optic density at 650 nm and the Lecithin/Sphingomyelin ratio, evaluated from the quantitative point of view according to the method of Gluk and Coll. The results show a significant correlation between samples with optic density greater than or equal to 0.15 and those with L/S ratio greater than or equal to 2.0. Finally, the Authors analyze the possible usefulness of this method as a rapid test to assess foetal pulmonary maturity.

Amniotic Fluid↗
PubMedDate not supplied

Expression of AP-2 transcription factor and of its downstream target genes c-kit, E-cadherin and p21 in human cutaneous melanoma.

The AP-2 transcription factor plays a pivotal role in regulating the expression of several genes involved in tumor growth and progression of melanoma. We determined, by Western blot, variation in the level of expression of AP-2 and three of its downstream targets, c-kit, E-cadherin, and p21 in several human melanoma cell lines and, by immunohistochemistry, in a group of 99 histological samples including benign and malignant melanocytic lesions. A significant negative correlation between AP-2 expression level and tumor thickness was found. Moreover, AP-2 expression was positively associated with E-cadherin and c-kit expression. In contrast, there was a significant negative association between AP-2 and p21 expression levels. These findings suggest that p21 is independent of AP-2 transactivator function during the latest phases of melanoma progression. Finally, AP-2, c-kit, E-cadherin, and p21 expression levels did not show to be able to distinguish between dysplastic nevi and nevi without dysplasia. We conclude that changes in the expression of these proteins are involved in the later phases of melanoma progression, and may be responsible for the transition from local invasive melanoma to metastasis.

Blotting, Western↗
PubMedDate not supplied

Ventricular myosin pattern of spontaneously hypertensive turkeys is unaffected by labetalol treatment.

In most animal species, left ventricular hypertrophy due to pressure overload is associated with an advantageous increase of the "slow" V3 isomyosin. In contrast, in spontaneously hypertensive turkeys, the development of left ventricular hypertrophy is associated with the synthesis of a "fast" V1-like isomyosin, with high incidence of cardiac failure. This could be related to the high catecholamine levels found in these animals. This is why we studied the ventricular myosin pattern after lowering of blood pressure and regression of cardiac hypertrophy obtained by means of labetalol, and alpha- and beta-blocking drug which inhibits the effects of catecholamines. From the 2nd to the 32nd week of age, 22 turkeys were treated with increasing doses of p.o. labetalol (from 20 to 35 mg/kg body weight daily) and 16 other turkeys were given daily p.o. placebo. Blood pressure and heart rate were periodically measured by an indirect method. After sacrifice, the degree of cardiac hypertrophy was evaluated by the biventricular weight to body weight ratio, ventricular myosin was purified, Ca++-activated ATPase activity assessed, and ventricular myosin pattern was determined by two-dimensional gel electrophoresis of myosin heavy chains. Plasma and cardiac catecholamines were measured by high performance liquid chromatography. Throughout the study period, blood pressure and heart rate were significantly reduced in the labetalol-treated animals as compared to the untreated ones. At the end of the study period, the ventricular mass was significantly lower in the labetalol group. Nevertheless, no differences were observed in ventricular myosin pattern and Ca++-activated ATPase activity levels between the two groups. In the labetalol group, an increase in plasma catecholamines and only a slight, but not significant, increase in cardiac catecholamines was found. These data indicate that in spontaneously hypertensive turkeys, the synthesis of the "fast" V1-like isomyosin is not influenced by known pathophysiological stimuli like blood pressure, cardiac hypertrophy and catecholamines.

Animals↗
PubMedDate not supplied

Isomyosin redistribution in chronic pressure overload: comparison between peptide mapping and electrophoresis under non-denaturing conditions.

Chronic pressure overload induces a redistribution in myosin isoenzymes as demonstrated by Ca++-activated ATPase activity, electrophoresis under non-denaturing conditions and immunohistochemistry. We compared, in two groups of renal hypertensive rats and control rats, the isoenzymic patterns obtained by electrophoresis under non-denaturing conditions with those observed after heavy chains digestion with S. Aureus V8 protease. In the hypertensive animals in which a shift towards the "slow" V2 and V3 isomyosins was evident, peptide mapping always gave origin to a band which was not present in the controls. Since we consider this peptide as a marker of the redistribution towards the "slow" isoforms, peptide mapping according to Cleveland appears to be a simple and useful method to assess differences in isomyosin composition, at least between hypertrophic pressure-overloaded and normal rat ventricles. Moreover, in our experience this technique is simple, the patterns obtained from highly purified substrates are very reproducible and the digestion allows easy and clear comparisons.

Animals↗