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V Vulpis

Publications and source records attributed to V Vulpis.

At least 19 recordsLinked to original sources
PubMed1996

Carrier-mediated transport controls hydroxyproline catabolism in heart mitochondria from spontaneously hypertensive rat.

In this study we have investigated hydroxyproline transport in rat heart mitochondria and, in particular, in heart left ventricle mitochondria isolated from both spontaneously hypertensive and Wistar-Kyoto rats. Hydroxyproline uptake by mitochondria, where its catabolism takes place, occurs via a carrier-mediated process as demonstrated by the occurrence of both saturation kinetics and the inhibition shown by phenylsuccinate and the thiol reagent mersalyl. In any case, hydroxyproline transport was found to limit the rate of mitochondrial hydroxyproline catabolism. A significant change in Vmax and Km values was found in mitochondria from hypertensive/hypertrophied rats in which the Km value decreases and the Vmax value increases with respect to normotensive rats, thus accounting for the increase of hydroxyproline metabolism due to its increased concentration in a hypertrophic/hypertensive state.

Animals↗
PubMed1996

[Aging and isomyosin pattern of the left ventricle in spontaneously hypertensive and Wistar Kyoto rats].

Changes of the contractile proteins in the left ventricle from spontaneously hypertensive rats (SHR) are extensively documented with the development of the hypertensive state and with ageing. This study was undertaken to determine whether also the left ventricle from normotensive rats exhibits age-related changes of the myosin pattern. The relative distribution of myosin isoforms was investigated in Wistar Kyoto (WKY, n = 50) and SHR (n = 50), both at the 5th, 9th, 24th, 48th and the 72nd week of life. A significant decrease in V1 as well as an increase in V3 percentage values, compared to the data obtained at the 5th week were observed in SHR from the 9th week, concomitantly to the rise in blood pressure values. These changes were more consistent with ageing (5 weeks: V1 99.0 +/- 0.9%, V2 0.6 +/- 0.1%, V3 0.4 +/- 0.3%; 72 weeks: V1 5.3 +/- 3.9%, V2 3.0 +/- 2.7%, V3 91.7 +/- 9.7%). In WKY rats, a significant decrease in V1 percentage values was detected at the 24th week and it was evident till the 72nd week. V3 significantly changed only at the 48th and the 72nd week (5 weeks: V1 100.0 +/- 0.0%; 72 weeks: V1: 41.4 +/- 6.5%, V2 13.3 +/- 2.8%, V3 45.5 +/- 6.9%). The results of this study confirm that alterations in the left ventricle isomyosin pattern occur early in SHR with the rise in blood pressure values and the increase in left ventricular mass. In contrast, modifications in the myosin isoform distribution were found only in WKY with ageing. These findings may be related to the biochemical changes occurring in the myocardial tissue either gradually, during the advanced ages of life, or early due to the hypertensive state.

Aging↗
PubMed1995

Left ventricular hypertrophy in spontaneously hypertensive rat: effects of ACE-inhibition on myocardiocyte ultrastructure.

The aim of this study is to investigate the effects of two ACE-inhibitors with different chemical formulae, cilazapril (CLZ) and captopril (CPT), on left ventricular myocardiocytes from spontaneously hypertensive rats (SHR), characterized by ultrastructural alterations associated with left ventricular hypertrophy, and from Wistar-Kyoto (WKY) rats, considered as controls. After CLZ-treatment, not remarkable changes are observed in WKY myocardiocytes, whereas SHR ones show a considerable reduction in their original alterations in ultrastructure. After CPT-treatment, both SHR and WKY myocardiocytes are altered in ultrastructure. The morphometric investigation confirms that CPT and CLZ produce different effects. Even if the drugs induce a similar decrease in blood pressure and left ventricular mass index, CLZ unlike CPT seems to improve the ultrastructural abnormalities associated with left ventricular hypertrophy. These changes could be related to the different chemical structure of CLZ and CPT, or to a different affinity of the two drugs for the local renin-angiotensin system.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1995

Changes in enzyme levels in hypertensive heart tissue.

The levels of activity of some enzymes involved in oxidative metabolism have been determined in left ventricular tissue from spontaneously hypertensive rats compared with those in normotensive controls. Levels of pyruvate kinase were increased about 1.3 fold indicative of elevated glycolytic activity. Similarly, enhanced levels of lactate dehydrogenase were found, consistent with a requirement for increased oxidation of cytosolically-generated NADH. In addition a more active malate-aspartate shuttle, which in heart provides the major route for transfer of reducing equivalents to the mitochondria, was suggested by elevated levels of the cytosolic isoenzyme of aspartate aminotransferase; malate dehydrogenase did not increase but the activity of this enzyme is very high and unlikely to be rate-limiting in the shuttle. The levels of expression of mRNAs for three of these enzymes (pyruvate kinase, aspartate aminotransferase and malate dehydrogenase) were also determined and correlated well with the extent of change, if any, in the changes in enzymatic activity. Thus it seems that one response to development of hypertension in rats is an increase in expression of the genes for certain key enzymes involved in oxidative metabolism.

Animals↗
PubMed1994

Left-ventricular hypertrophy in the spontaneously hypertensive rat: effect of ACE inhibitors on ultrastructural morphology.

The ACE inhibitors cilazapril and captopril were administered at 10 and 100 mg/day, respectively, to spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto rats (WKY) from the 12th to the 22nd week of life. Both drugs produced statistically significant reductions in systolic and diastolic blood pressure, left-ventricular mass and index of left-ventricular hypertrophy in SHR. After cilazapril treatment, the morphology of SHR cardiocytes became similar to that in untreated normotensive rats, while in captopril-treated rats, myofibrils were disarranged, obliquely oriented and smaller than normal, with areas of electron-transparent sarcoplasm separating the myofibril bundles; mitochondria were also altered. In WKY rats, we observed no statistically significant changes in blood pressure, ventricular weight and hypertrophy index between the two drugs; however, there were different effects of the two drugs on the ultrastructural morphology of the myocardium. These observations suggest that these two molecularly dissimilar ACE inhibitors act differently at the tissue level despite similar effects on blood pressure and left-ventricular mass.

Animals↗
PubMed1994

Decrease of phagocytic functions in hypertensive rats.

The present investigation was aimed to examine non-specific immunologic capabilities of spontaneously hypertensive rats (SHR) during the development of hypertension. In vitro phagocytosis and oxidative killing exerted by monocytes, polymorphonuclear cells (PMN) and splenic macrophages (SpM0) were evaluated in SHR at 5-, 8-, and 24-weeks of age. Age-matched normotensive Wistar-Kyoto (WKY) rats were used as controls. Results showed that in pre-hypertensive stage (5-wk) there was no difference between SHR and WKY rats with regard to non-specific immunologic functions. Statistically significant differences in both phagocytosis and oxidative killing arose in early hypertensive stage (8-wk) and became more marked in adult SHR with established hypertension (24-wk). In conclusion, our data provide evidence of novel immunologic abnormalities in SHR in terms of ingestion and bactericidal phagocytic capabilities. The mechanisms responsible for these impaired immunologic functions may depend on various suppressive factors which will be object of discussion.

Aging↗
PubMed1994

[Clinical experience with alpha blockers and calcium antagonists in the perioperative treatment of pheochromocytoma].

This study aims to value the efficacy of the association between alpha-blockers and calcium channel-blockers, administered per os, in the reduction of preoperative preparation in patients with phaeochromocytoma and the calcium channel-blockers utility when are administered e.v. in the control of development of arterial paroxysmal hypertension during surgical manipulations. The trial had been conducted on 5 patients which have undergone the operation, before the operation we administered per os nifedipine and phonoxybenzamine for 8 days and during the operation we administered diltiazem e.v. The association between alpha-blockers and calcium-blockers per os, has reduced the preparation stage and has controlled the pressure parameters during the preoperative treatment. When we utilized diltiazem during the operation, we haven't note a good hemodynamic stability; these results are opposed to Tokioka's. Calcium channel-blockers and alpha-blockers seem to be a good therapy in the preoperative preparation of patients with phaeochromocytomas and they seem to be able to take fastly the standard of preoperative preparation.

Adolescent↗
PubMed1991

Comparison of the new alpha 1-blocker alfuzosin with propranolol as first-line therapy in hypertension.

The new alpha 1-blocker alfuzosin was compared with propranolol as monotherapy for hypertension in a double-blind, parallel group study of 8-week duration in 40 patients with essential hypertension. The patients (11 males, 29 females; mean age 47.8 +/- 2.2 years in the alfuzosin group and 46.6 +/- 2.4 years in the propranolol group) randomly received either alfuzosin from 2.5 mg b.i.d. up to 10 mg b.i.d. or propranolol from 40 mg b.i.d. up to 160 mg b.i.d. according to an individualized dose-titration schedule. The two groups were comparable with respect to disease history, cardiovascular risk factors, concomitant diseases, previous treatments and end-placebo blood pressure and heart rate values. Four patients did not complete the study, two patients in the alfuzosin group: one patient because of postural hypotension and the second one because of breast cancer; and two patients in the propranolol group: one patient for inefficacy and the second one lost to follow-up. At the end of the 8-week trial the mean daily doses were 12.2 +/- 0.61 mg and 196 +/- 9.82 mg for alfuzosin and propranolol, respectively. The antihypertensive effects of the two drugs were comparable. Upright and supine blood pressures decreased significantly with both treatments from the second week on (P less than 0.001 for all BP values). At the end of the 8-week double-blind trial, 83% of alfuzosin patients and 67% of propranolol patients were normalized. The two treatments differed significantly with respect to their effect on heart rate. Alfuzosin did not induce marked changes in heart rate: only a slight increase was observed. In contrast, propranolol caused bradycardia, more marked in the upright position. Palpitations, headache, asthenia and orthostatic hypotension were reported in the alfuzosin group. Asthenia and decreased libido were reported in the propranolol group. These data prove that alfuzosin has antihypertensive effects equivalent to propranolol and it is an interesting agent for the therapy of essential hypertension. It can be used as a first agent at doses between 5 and 20 mg/day with satisfactory therapeutic response and without relevant side-effects.

Adrenergic alpha-Antagonists↗
PubMed1991

[The effects of bisoprolol and atenolol on glucose metabolism in hypertensive patients with non-insulin-dependent diabetes mellitus].

Effects of bisoprolol and atenolol on glucose metabolism in hypertensive patients NIDDM. The aim of the study was to compare the antihypertensive efficacy and the effects on glucose metabolism of a new beta 1-selective beta-blocker with high beta 1 selectivity, bisoprolol and atenolol in 12 hypertensive patients (WHO classes I e II) suffering from untreated not insulin-dependent diabetes mellitus (NIDDM). According to a cross-over design after a placebo run-in period of 4 weeks, the patients were randomly allocated to receive bisoprolol 10 mg o.d. or atenolol 100 mg o.d. for 4 weeks, with a four-week wash-out period between the two active treatments. In basal condition and after each therapy an intravenous glucose tolerance test (i.v. GTT, 20 g) was performed, with evaluation of serum glucose and insulin at 0, 15, 30, 60, 90, 120 minutes and glycosuria during the test. At the same time blood pressure, heart rate (supine, upright), ECG, laboratory tests were assessed and subjective tolerability was evaluated. The glucose and insulin responses to the i.v. GTT did not significantly change to basal condition. Similarly glycosuria did not show significative increment during the test with both beta-blocking therapies. Blood pressure and heart rate values were significantly reduced (p less than 0.001) after bisoprolol and atenolol treatment. During the study no side effects were reported and laboratory tests and ECG remained substantially unchanged. These data confirm the antihypertensive efficacy of bisoprolol and atenolol and demonstrate the absence of important effects of these drugs on glucose metabolism in hypertensive patients with NIDDM.

Adrenergic beta-Antagonists↗
PubMed1990

[Effects of long-term treatment with captopril on the isomyosin profile of the heart from SHR and Wistar rats].

Heart myosin isoforms and arterial blood pressure changes were studied in 30 SHR rats following a long-term treatment with captopril. 30 Wistar rats were included in the same trial as control. Twelve week old SHR rats with an already established hypertension and ventricular hypertrophy were orally administered with between 25 and 100 mg/Kg/die of captopril. After a ten-week treatment, animals were sacrificed and heart myosin isoforms (V1, V2, V3) analysed by polyacrylamide gel electrophoresis. Our results showed that captopril can: a) reduce blood pressure; b) reduce the cardiac hypertrophy; c) reverse the isomyosin enzymes (V1 V3) previously altered by the hypertrophy condition (V3 V1) to normal value. Furthermore we have detected an increase of V myosin isoform in SHR rats (35%) and to a lower extent in treated Wistar rats (17%). Since SHR and Wistar rats usually do not express V isoform, our results suggest that captopril may be responsible for this phenomenon by acting directly on myocardial cells.

Animals↗
PubMed1990

[Effects of long-term treatment with calcium antagonists on the isomyosin composition of the hearts of spontaneously hypertensive rats].

Purpose of this study was to evaluate the long-term effects of treatment by calcium antagonists on blood pressure (BP) and cardiac isomyosins of SHR. From the fourth week of life we studied 40 SHRs and 20 Wistars in standard conditions and at the twelfth week, when SHRs already showed high BP and left ventricular hypertrophy (LVH), we treated 10 of them by nifedipine (N) (30 mg/Kg/die) and 10 by verapamil (V) (100 mg/Kg/die). BP was measured by tail-cuff technique. At the tenth week of treatment when the rats were sacrificed, LVH index and isomyosinic profile were evaluated. The results obtained demonstrate that: at the twenty-second week, V1 was 17% in untreated SHR, 90% in N and 75% in V while V3 was 80% in the untreated group, 8% in N and 15% in V, respectively. In conclusion, the treatment by calcium antagonists reduced BP and LVH re-establishing the predominance of V1 on V3.

Animals↗
PubMed1990

[Reactivity of the aorta from spontaneously hypertensive rats before and after endothelial removal].

In the present study the mechanic activity of SHR and Wistar rat's aorta was evaluated, in vitro, after stimulation by chloride of potassium, phenylephrine, norepinephrine, histamine, serotonin and acetylcholine, before and after the removal of the endothelium. The aorta rings of the rats were taken before the development of the hypertensive state (7th week) and at 18th week (when the SHR rats already showed established hypertension starting since IXth week of life), and successively suspended in a bath for isolated organ. The mechanic activity was measured by isometric transductor. The obtained findings show an increased sensitivity, in SHRs, to (K+), NA and FeE, if these are compared with the control group, since the prehypertensive stage (7th week). The removal of the endothelium didn't modify the response amplitude to K in both the breeds, while the maximum response amplitude, provoked by NA and FeE, significantly increased in SHRs compared to controls. The relaxation induced by the vasodilator agents (Ach-H-5HT) was completely absent in the SHR rats' aorta with established hypertension. In conclusion, these results suggest a functional deterioration of the endothelial cells, in the hypertensive animals, that could contribute to increase the peripheric vascular resistances observed during hypertension.

Animals↗