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Biomedical subjects

V Vulpis

Publications and source records attributed to V Vulpis.

32 records · Page 2Linked to original sources
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↗
PubMed1989

[Changes of cardiac myosin in spontaneously hypertensive rats and control rats, during the various stages of development of essential arterial hypertension].

The aim of this research was to assess left ventricular myosin alterations of Sh, rats during the various phases in which primitive hypertension developed. Two groups of animals were examined: one comprised spontaneously hypertension rats (Shr) and the other controls. Both groups were studied from the 5th to 31st week of life. The Shrs became hypertensive at 9 weeks of age. The animals were sacrificed at: 5-7-9-12-16-24-31 weeks of age. The left ventricles were separated from their hearts and native myosin in non dissociated conditions was then obtained by polyacrylamide gel electrophoresis; heavy chains and light chains were separated with S.D.S. One of the findings showed that in the control rats the myosin iso-enzyme V1 always prevailed over the myosin iso-enzyme V3 during all the stages of life examined. In the Shrs, starting from the iso-enzyme V3 increased proportionally. The heavy chains showed the same behavior as the native protein while there were no significant differences for the light chains in both groups of animals. In conclusion, our findings show that the structural and biochemical compensation variations which several authors have demonstrated in other conditions of experimental hypertension occur in Sh rats as well.

Animals↗
PubMed1989

[In vitro reactivity of the aorta of SHR rats and Wistar rats, in the various developmental phases of arterial hypertension: role of the endothelium].

The mechanical reactivity of SHR and Wistar rats' aortas was evaluated, in vitro, after stimulation by potassium chloride (K+), phenylephrine (Phe), norepinephrine (NE), histamine (H), serotonin (5-HT) and acetylcholine (Ach), before and after the removal of the endothelium. The aortic rings were taken at different ages and stages of the hypertensive state (that in the SHRs started at the ninth week of life) and successively suspended in a bath for isolated organs. The mechanical activity was measured by isometric transducers. In SHR rats an increased sensitivity to K+, NE and Phe compared with the control group, and preceding the hypertensive stage, was found. The removal of the endothelium did not modify the response amplitude to K in both the breeds, while the maximum response amplitude, provoked by NE and Phe, significantly increased in SHRs compared to controls. The relaxation induced by vasodilator agents (Ach, H, 5-HT) was significantly reduced in the SHR rats' aortas with initial hypertension (12th week) if compared with Wistar rats at the same age. The release response was completely absent in the SHR rats' aortas with established hypertension (18th week). In conclusion, these results suggest that, in hypertensive rats, a functional deterioration of the endothelial cells occurs: this may contribute to the increase in peripheral vascular resistance observed during hypertension.

Animals↗
PubMedDate not supplied

Non-invasive haemodynamic study in hypertensive subjects after treatment with verapamil slow release.

Aim of this study is to investigate the haemodynamic effects, after the short and long-term antihypertensive treatment. After a wash-out period and a placebo treatment period, 30 hypertensive patients received verapamil SR (slow release, 240 mg o.d.) for 30 days. A significant decrease in systolic and diastolic blood pressure was obtained already 4 h after the first administration of verapamil; it was more evident and persistent throughout the study. No significant changes of heart rate or PR interval in ECG were observed. A significant decrease in total vascular resistances, both supine and upright, was evident already 4 h after the drug intake and observed throughout the study. The major effect was obtained after one month. No significant changes of cardiac output, cardiac index and stroke volume were recorded. Furthermore, plasma verapamil levels were measured to confirm that the haemodynamic effects are obtained by low drug concentrations. The present study provides evidence that the antihypertensive effect of verapamil, whose mechanism is the reduction of total vascular resistances, is progressive, long acting and achieved by low plasma levels, when slow release formulation is considered.

Adult↗
PubMedDate not supplied

Efficacy of biofeedback treatment compared with drug therapy in hypertensive patients.

To assess the ability of biofeedback (BFB) in controlling hypertension a study was made of 40 hypertensive patients selected by means of the cardiovascular response to an arithmetic test. The patients were divided into four treatment groups: 10 patients were treated with diuretic therapy (D-T), 10 with beta-blocker therapy (Bb-T), 10 with BFB treatment, while 10 had no treatment at all (N-T). The BFB treatment consisted of 36 sittings where patients were requested to control muscular contraction, peripheric temperature and heart rate (HR) by means of a correlated acoustic signal. The results for blood pressure and HR reductions were compared during a 12-month follow-up period. The results for systolic blood pressure, diastolic blood pressure and HR indicate the efficacy of BFB for selected patients and suggest the possibility of using BFB treatment in the first stages of suspected neurogenic hypertension.

Adult↗
PubMedDate not supplied

Short-term preoperative treatment in a case of pheochromocytoma.

The authors show the case of a young drug addict patient with chronic hepatitis affected by pheochromocytoma, owing to his conditions, which was prepared preoperatively with a short term phenoxybenzamine i.v. We had no complications in the perioperative period. Our opinion is that it is possible, when necessary, to administer a short term therapy but this preparation isn't be considered a standard therapeutic program.

Adrenal Gland Neoplasms↗
PubMedDate not supplied

[Plasma levels and noninvasive hemodynamic profile of slow release verapamil (240 mg). A multicenter study].

Aim of this study was to evaluate the antihypertensive efficacy, tolerability, drug plasma levels and hemodynamic effects after long-term treatment with the slow release (SR) formulation of verapamil (240 mg od). After a wash-out period of two weeks, 96 subjects (39 M, 57 F; mean age: 55 +/- 8.4 years; recruited in 9 centers) with mild to moderate, uncomplicated hypertension received verapamil 240 mg SR od for 24 weeks. The following parameters were considered: systolic (SBP) and diastolic (DBP) blood pressure, heart rate (HR), ECG, echocardiogram, routine blood and urine chemistries, drug plasma levels. In addition, hemodynamic parameters were assessed in 30 subjects. A significant decrease in SBP and DBP (p < 0.01) was observed already after 1 week of treatment and was evident during all the study. HR was significantly reduced after 4 weeks (p < 0.01). No changes of ECG and echocardiographic parameters occurred. A significant increase in drug plasma levels was measured after 12 and 24 weeks of treatment (p < 0.05), when compared to the values recorded after 1 week. After 24 weeks drug levels were slightly decreases, even if not significantly, when compared to the values observed at the 12th week. No significant changes of cardiac output (CO), cardiac index (CI), stroke volume (SV) were evident. Total vascular resistances (TVR) decreases significantly (p < 0.001) 80 subjects completed the study. These results confirm the antihypertensive efficacy and tolerability of SR formulation of verapamil and suggest that the effective mechanism by which it reduces blood pressure is the progressive reduction of TVR without a sympathetic reflex stimulation. This hemodynamic effect is achieved by small drug concentrations. In conclusion, SR formulation of verapamil allows a good therapeutic control in hypertensive subjects when it is administered od and, therefore, it can be considered a drug of first choice in the treatment of arterial hypertension.

Delayed-Action Preparations↗