Biomedical subjects

L F Carbonell

Publications and source records attributed to L F Carbonell.

43 records · Page 3Linked to original sources

PubMed1985

Effect of captopril on norepinephrine vascular contractility.

In isolated aortic rings and in vitro perfused mesenteric arteries of Wistar rats the vasoconstrictor responses to norepinephrine (NE) were not affected by captopril (2 X 10(-4) M). However, captopril (1 mg/kg i.v.) in pithed Wistar rats attenuated significantly the increases in diastolic blood pressure induced by NE. In pithed rats the effect of captopril on NE diastolic blood pressure responses disappeared either in the presence of an angiotensin II (5 ng X kg-1 X min) infusion or when the rats were previously nephrectomized. These findings suggest that the effect of captopril on vascular responses to norepinephrine is mediated by an inhibition of the renin-angiotensin system and not by an antagonistic effect on alpha-adrenergic receptors.

Angiotensin II↗

PubMed1985

Baculovirus-mediated expression of bacterial genes in dipteran and mammalian cells.

A recombinant baculovirus containing the Escherichia coli chloramphenicol acetyltransferase (CAT) gene under the control of the Rous sarcoma virus long terminal repeat promoter and the E. coli beta-galactosidase gene under the control of the very late baculoviral polyhedrin promoter was used to determine if Autographa californica nuclear polyhedrosis virus, a baculovirus of Lepidoptera, can enter and express viral DNA in dipteran (Drosophila sp.) and mammalian (Mus sp.) cells that are considered refractory to baculovirus replication. Following infection, CAT gene expression was observed in both dipteran and mammalian cells, but expression in the mammalian cell line was less than 0.05% of that observed in either dipteran or lepidopteran cells. Although the level of CAT gene expression was similar in permissive lepidopteran and nonpermissive dipteran cells, expression of beta-galactosidase activity from the late polyhedrin promoter in dipteran or mammalian cells was less than 0.3% of the levels observed in lepidopteran cells. These results indicate that foreign gene expression in nonpermissive cells is promoter dependent and that late viral gene expression is restricted in these cells. The Rous sarcoma virus long terminal repeat allows substantial CAT gene expression in both a D. melanogaster cell line and Aedes aegypti midgut cells. Baculovirus DNA undergoes a limited number of replications in Drosophila cells. The results are relevant to baculovirus host range, the safety of baculoviruses as pesticides, and the development of baculovirus pesticides with expanded host ranges.

Acetyltransferases↗

PubMed1985

Role of sodium balance on maintenance of blood pressure in the chronic phase of two-kidney, one-clip hypertension.

Blood pressure and sodium balance have been studied after unclipping, nephrectomy and sham operation of ischemic kidney in the chronic phase (16 weeks) of two-kidney, one clip hypertension. In hypertensive rats the fractional excretion of sodium was 85.5 +/- 2.3% and blood pressure (BP) was significantly increased (187.1 +/- 4.5 mmHg, p less than 0.001). Removal of either the constricting clip or ischemic kidney induced a decrease of BP to normal level whereas sham operation did not produce any change. However, rats submitted to these three experimental manipulations showed, at 1, 2, 3 and 4 days, and at 3 weeks, similar changes in sodium excretion. In the groups with unclipping or nephrectomy of ischemic kidney, water intake was less and urine volume smaller than in the sham operated group. These results suggest that a positive sodium balance is not important to maintain hypertension at this stage and that changes in sodium balance, after both unclipping and nephrectomy of ischemic kidney, have no influence in BP normalization.

Animals↗

PubMed1985

Normal hemodynamic parameters in conscious Wistar rats.

The evolution of different hemodynamic parameters with ponderal growth has been studied in conscious Wistar rats. The thermodilution method has been used to determine cardiac output and related variables. The results suggest that, between animal weight and the different hemodynamic parameters, there is a direct proportional relationship to blood volume, mean arterial pressure, cardiac output, stroke volume and total peripheral resistance, and an indirect proportional relationship to heart rate, cardiac index and stroke volume index. Body weight, therefore, plays a major role in hemodynamic determination, this having to be kept in mind when designing the experiment.

Animals↗

PubMed1983

[Participation of the renin-angiotensin system in experimental renovascular hypertension].

Hypertension was induced in Wistar rat by means of a clip in the left renal artery. After two weeks (acute stage) and sixteen weeks (chronic stage) the animals had a significant increase in arterial pressure (AP) and plasma renin activity (PRA). At both stages, nephrectomy or revascularization of the ischemic kidney returned AP and PRA to the normal level, both in the short term (1 day) and long term (60 days).

Animals↗

PubMed1983

[Hemodynamic changes in the acute phase of experimental hypertension].

The arterial pressure, heart rate, cardiac output, stroke volume, total peripheral resistance and plasma angiotensin II were measured in Wistar rats and 24 hours after arterial renal constriction by a clip (0.20 mm d.i.). The results were compared with those obtained in a sham operated group. The experimental group showed an increase in arterial pressure and total peripheral resistance without changes in heart rate, cardiac output and stroke volume. In hypertensive animals there was a greater level of plasma angiotensin II than in control group. These studies have demonstrated that 24 hours after renal arterial stenosis the increase in arterial pressure can be mediated by an increased activity of the renin-angiotensin system.

Angiotensin II↗

PubMedDate not supplied

Role of renin-angiotensin and sympathetic nervous systems in the chronic phase of two-kidney, one-clip hypertension in rats.

The purpose of the present study was to examine the role of the renin-angiotensin and the sympathetic nervous systems during the chronic phase (greater than 16 weeks) of two-kidney, one-clip hypertension in conscious unrestrained rats. During this phase, the mean arterial pressure (MAP) (p less than 0.001) and plasma angiotensin II (31.9 +/- 1.5 to 125.8 +/- 19.9 pg/ml, p less than 0.005) were significantly increased as compared to normotensive group. Converting enzyme inhibition by captopril produced a significant decrease of MAP (181.2 +/- 8.2 to 140.0 +/- 5.5 mmHg, p less than 0.001). This hypotensive response was similar when aprotinin (a Kallikrein inhibitor) and captopril were infused simultaneously. Alpha 1-adrenergic receptor blockade by phenoxybenzamine (POB) significantly decreased but did not normalize MAP (179.8 +/- 12.4 to 135.8 +/- 10.4 mmHg, p less than 0.001). However, when infused after POB, captopril induced a further decrease of MAP to 86.7 +/- 9.4 mmHg (p less than 0.001). This MAP level was not different from that found in normotensive rats after infusion of the two drugs (83.2 +/- 5.3 mmHg). These results suggest that both the renin-angiotensin system and the sympathetic nervous system, by activating peripheral alpha 1-adrenergic receptors, maintain the high blood pressure during the chronic phase (greater than 16 weeks) of two-kidney, one-clip hypertension in conscious rats.

Angiotensin II↗