Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (D... more Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (DF, dengue fever) to the more severe forms of hemorrhagic fever/dengue shock syndrome (DHF/DSS). The aim of this study was the serological and molecular confirmation of an outbreak of dengue in Falcon state, Venezuela. A total of 54 sera from patients with clinical diagnosis of DV infection were analyzed by an enzyme immunoassays developed in Venezuela (ELISA -IgM e -IgG) and by PCR. From them, 78% exhibited DV infection (PCR+ y/o IgM+), 48% exhibited viremia by PCR and 57% were positive to IgM. An interesting observation was the high percent (76%) of patients with past or secondary infection (IgG positive), which included all the patients exhibiting clinical symptoms of DHF (n = 8). From the PCR positive sera, serotype 1 was found in 27%, serotype 2 in 54% and serotype 4 in 19%. No serotype 3 was found circulating in this population, although this serotype was already circulating in the ...
Pa pel del sis te ma re ni na an gio ten si na en la res pues ta sim pá ti ca in du ci da por la ... more Pa pel del sis te ma re ni na an gio ten si na en la res pues ta sim pá ti ca in du ci da por la prue ba pre so ra al frío en hu ma nos.
Pa pel del sis te ma re ni na an gio ten si na en la res pues ta sim pá ti ca in du ci da por la ... more Pa pel del sis te ma re ni na an gio ten si na en la res pues ta sim pá ti ca in du ci da por la prue ba pre so ra al frío en hu ma nos.
Background: Discrepancies concerning the effect of hypertension on capillaries and muscle fiber t... more Background: Discrepancies concerning the effect of hypertension on capillaries and muscle fiber types in skeletal muscle have been reported. This study demonstrates the effects of hypertension produced by deoxicorticosterone acetate (DOCA) and salt load on the extensor digitorum longus (EDL) and soleus muscles of the rat.
Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (D... more Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (DF, dengue fever) to the more severe forms of hemorrhagic fever/dengue shock syndrome (DHF/DSS). The aim of this study was the serological and molecular confirmation of an outbreak of dengue in Falcon state, Venezuela. A total of 54 sera from patients with clinical diagnosis of DV infection were analyzed by an enzyme immunoassays developed in Venezuela (ELISA -IgM e -IgG) and by PCR. From them, 78% exhibited DV infection (PCR+ y/o IgM+), 48% exhibited viremia by PCR and 57% were positive to IgM. An interesting observation was the high percent (76%) of patients with past or secondary infection (IgG positive), which included all the patients exhibiting clinical symptoms of DHF (n = 8). From the PCR positive sera, serotype 1 was found in 27%, serotype 2 in 54% and serotype 4 in 19%. No serotype 3 was found circulating in this population, although this serotype was already circulating in the ...
Atrial natriuretic peptide (ANP) or an Atriopeptin III analog (PL 058) stimulated cGMP formation ... more Atrial natriuretic peptide (ANP) or an Atriopeptin III analog (PL 058) stimulated cGMP formation in the membrane fraction of rat olfactory bulb, median eminence and paraventricular nucleus, in a dose-dependent manner. The effect of the Atriopeptin III analog was 20-40% greater than that of ANP. Bilateral adrenalectomy, with or without mineralo- or glucocorticoid-replacement, on ANP-stimulated cGMP formation was investigated in rat paraventricular nucleus. 11 days after bilateral adrenalectomy a reduced responsiveness to ANP- or PL 058-induced cGMP production was observed. This effect was prevented by deoxycorticosterone, but not by dexamethasone administration. Our results further support the presence of guanylate cyclase-coupled ANP receptors in brain localized target sites; and they provide evidence suggesting that guanylate cyclase-linked ANP binding sites in the PVN are susceptible to regulatory changes after adrenalectomy-induced activation of the hypothalamus-hypophyso-adrenocortical system.
Losartan, a nonpeptide angiotensin II receptor antagonist, was used to establish the role of brai... more Losartan, a nonpeptide angiotensin II receptor antagonist, was used to establish the role of brain AT1 angiotensin II receptor subtype on the natriuretic, antidiuretic, and dipsogenic actions of centrally administered renin. Intracerebroventricular administration of renin reduces urine volume and increases sodium excretion and water intake in conscious, male, hydrated rats. Losartan (3 or 10 mg/kg, sc) reduced the increased sodium excretion and totally inhibited the antidiuretic action induced by intracerebroventricular renin. When both renin and Losartan were given intracerebroventricularly, at the highest dose, there was a potent inhibition of the antidiuretic and natriuretic actions. Peripheral and central administration of the AT1 receptor blocker significantly lengthened the onset of drinking behavior and reduced the cumulative water intake observed after intracerebroventricular injection of renin. Our results strongly suggest that the brain AT1 receptor subtype mediates the physiologic actions of angiotensin II, such as drinking behavior, the increase in sodium excretion, and vasopressin release.
This study assessed the effect of non-peptide angiotensin II receptor subtype antagonists on the ... more This study assessed the effect of non-peptide angiotensin II receptor subtype antagonists on the cardiovascular response to footshock. Effects of electric stimulation (1, 2 or 5 Hz) on mean arterial pressure (MAP) and heart rate (HR) were determined. Peripheral or central administration of losartan, an angiotensin AT 1 receptor antagonist (1 or 10 mg/kg s.c., or at 10, 30 or 100 /~g/5 Izl i.c.v.), inhibited the mean arterial pressure response but not the heart rate response to footshock. In contrast, the MAP response to exogenous administration of norepinephrine was not inhibited by subcutaneous administration of losartan (10 mg/kg). Given at 100/~g/5/el i.c.v., the angiotensin ATe-selective receptor antagonist, PD 123319, did not reduce hemodynamic responses to electric stimulation. These results suggest that, in acute stress, endogenous angiotensin II facilitation of noradrenergic transmission is mediated through the angiotensin AT 1 receptor.
ISRAEL, A., M. TORRBS, M. CIERCO AND Y. BARBBLLA. Further evidence for a dopaminergic involvement... more ISRAEL, A., M. TORRBS, M. CIERCO AND Y. BARBBLLA. Further evidence for a dopaminergic involvement in the renal action of centrally administered atrial natriuretic peptide in rats. BRAIN RES BULL 27(S) 739-742, 1991. -Intracerebroventricular (ICV) administration of atria1 natriuretic peptide (ANP) induces an increase of urinary volume and sodium excretion in conscious male hydrated rats. The involvement of brain dopaminergic neurones in the ICV-ANP renal action was investigated. Diuretic and natriuretic action of ANP was prevented by inhibition of tyrosine hydroxylase activity with alpha-methyl-p-tyrosine treatment and was absent following selective central dopaminergic denervation with ICV administration of 6-hydroxydopamine in combina-
The aim of this study was to evaluate the effect of short-term administration of the AT 1 angiote... more The aim of this study was to evaluate the effect of short-term administration of the AT 1 angiotensin II receptor antagonists, eprosartan, on 10 the sympathetic response to cold pressor test (CPT) in normotensive healthy volunteers. Sixty-nine healthy volunteers were included in this 11 double-blind placebo-controlled study. Blood pressure and heart rate were determined before and 175min after oral administration of 12 placebo, losartan (50 mg) or eprosartan (600 mg). Immediately, the subjects underwent CPT and then the same hemodynamic variables were 13 measured. CPT increased arterial blood pressure (systolic, diastolic and mean) and HR in placebo-treated group. Pretreatment with a single 14 dose of losartan or eprosartan blunted CPT-induced pressor response, but not the rise in heart rate. Our results demonstrate that endogenous 15 angiotensin II, through stimulation of AT 1 receptor, supports sympathetic mediated stress-response in humans. 16 D
Footshocks increases mean arterial pressure and heart rate. Systemic or intracerebroventricular (... more Footshocks increases mean arterial pressure and heart rate. Systemic or intracerebroventricular (IVT) administration of losartan, a specific angiotensin AT1 receptor antagonist, not only inhibited the pressor response to footshocks but resulted in vasodepression. Peripheral or IVT administration of PD 123319, a specific angiotensin AT2 receptor antagonist, did not alter the haemodynamic response to footshocks. However, simultaneous blockade of angiotensin AT1 and AT2 receptors by combined systemic or central administration of losartan and PD 12319, eliminated the vasodepressor response to footshocks unmasked in losartan pretreated rats. Our data suggest that activation of peripheral or brain angiotensin AT2 receptor mediated the vasodepressor response to footshocks in the presence of angiotensin AT1 receptor antagonist. We studied the role of kinins and nitric oxide in the vasodepressor response observed after footshocks. The decrease in mean arterial pressure observed after footshocks in losartan treated rats was blunted by systemic or IVT administration of icatibant (HOE 140) or N(G)-nitro-L-arginine-methyl ester, indicating that peripheral or brain kinins and nitric oxide are involved in the hypotensor response to footshocks during angiotensin AT1 receptor blockade. Our results suggest a role for angiotensin AT2 receptor in the regulation of arterial blood pressure, possibly through the release of vasodilator autacoids such as bradykinins and nitric oxide.
Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (D... more Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (DF, dengue fever) to the more severe forms of hemorrhagic fever/dengue shock syndrome (DHF/DSS). The aim of this study was the serological and molecular confirmation of an outbreak of dengue in Falcon state, Venezuela. A total of 54 sera from patients with clinical diagnosis of DV infection were analyzed by an enzyme immunoassays developed in Venezuela (ELISA -IgM e -IgG) and by PCR. From them, 78% exhibited DV infection (PCR+ y/o IgM+), 48% exhibited viremia by PCR and 57% were positive to IgM. An interesting observation was the high percent (76%) of patients with past or secondary infection (IgG positive), which included all the patients exhibiting clinical symptoms of DHF (n = 8). From the PCR positive sera, serotype 1 was found in 27%, serotype 2 in 54% and serotype 4 in 19%. No serotype 3 was found circulating in this population, although this serotype was already circulating in the ...
Pa pel del sis te ma re ni na an gio ten si na en la res pues ta sim pá ti ca in du ci da por la ... more Pa pel del sis te ma re ni na an gio ten si na en la res pues ta sim pá ti ca in du ci da por la prue ba pre so ra al frío en hu ma nos.
Pa pel del sis te ma re ni na an gio ten si na en la res pues ta sim pá ti ca in du ci da por la ... more Pa pel del sis te ma re ni na an gio ten si na en la res pues ta sim pá ti ca in du ci da por la prue ba pre so ra al frío en hu ma nos.
Background: Discrepancies concerning the effect of hypertension on capillaries and muscle fiber t... more Background: Discrepancies concerning the effect of hypertension on capillaries and muscle fiber types in skeletal muscle have been reported. This study demonstrates the effects of hypertension produced by deoxicorticosterone acetate (DOCA) and salt load on the extensor digitorum longus (EDL) and soleus muscles of the rat.
Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (D... more Dengue virus (DV) is responsible for a spectrum of diseases, from a self-limited fever disease (DF, dengue fever) to the more severe forms of hemorrhagic fever/dengue shock syndrome (DHF/DSS). The aim of this study was the serological and molecular confirmation of an outbreak of dengue in Falcon state, Venezuela. A total of 54 sera from patients with clinical diagnosis of DV infection were analyzed by an enzyme immunoassays developed in Venezuela (ELISA -IgM e -IgG) and by PCR. From them, 78% exhibited DV infection (PCR+ y/o IgM+), 48% exhibited viremia by PCR and 57% were positive to IgM. An interesting observation was the high percent (76%) of patients with past or secondary infection (IgG positive), which included all the patients exhibiting clinical symptoms of DHF (n = 8). From the PCR positive sera, serotype 1 was found in 27%, serotype 2 in 54% and serotype 4 in 19%. No serotype 3 was found circulating in this population, although this serotype was already circulating in the ...
Atrial natriuretic peptide (ANP) or an Atriopeptin III analog (PL 058) stimulated cGMP formation ... more Atrial natriuretic peptide (ANP) or an Atriopeptin III analog (PL 058) stimulated cGMP formation in the membrane fraction of rat olfactory bulb, median eminence and paraventricular nucleus, in a dose-dependent manner. The effect of the Atriopeptin III analog was 20-40% greater than that of ANP. Bilateral adrenalectomy, with or without mineralo- or glucocorticoid-replacement, on ANP-stimulated cGMP formation was investigated in rat paraventricular nucleus. 11 days after bilateral adrenalectomy a reduced responsiveness to ANP- or PL 058-induced cGMP production was observed. This effect was prevented by deoxycorticosterone, but not by dexamethasone administration. Our results further support the presence of guanylate cyclase-coupled ANP receptors in brain localized target sites; and they provide evidence suggesting that guanylate cyclase-linked ANP binding sites in the PVN are susceptible to regulatory changes after adrenalectomy-induced activation of the hypothalamus-hypophyso-adrenocortical system.
Losartan, a nonpeptide angiotensin II receptor antagonist, was used to establish the role of brai... more Losartan, a nonpeptide angiotensin II receptor antagonist, was used to establish the role of brain AT1 angiotensin II receptor subtype on the natriuretic, antidiuretic, and dipsogenic actions of centrally administered renin. Intracerebroventricular administration of renin reduces urine volume and increases sodium excretion and water intake in conscious, male, hydrated rats. Losartan (3 or 10 mg/kg, sc) reduced the increased sodium excretion and totally inhibited the antidiuretic action induced by intracerebroventricular renin. When both renin and Losartan were given intracerebroventricularly, at the highest dose, there was a potent inhibition of the antidiuretic and natriuretic actions. Peripheral and central administration of the AT1 receptor blocker significantly lengthened the onset of drinking behavior and reduced the cumulative water intake observed after intracerebroventricular injection of renin. Our results strongly suggest that the brain AT1 receptor subtype mediates the physiologic actions of angiotensin II, such as drinking behavior, the increase in sodium excretion, and vasopressin release.
This study assessed the effect of non-peptide angiotensin II receptor subtype antagonists on the ... more This study assessed the effect of non-peptide angiotensin II receptor subtype antagonists on the cardiovascular response to footshock. Effects of electric stimulation (1, 2 or 5 Hz) on mean arterial pressure (MAP) and heart rate (HR) were determined. Peripheral or central administration of losartan, an angiotensin AT 1 receptor antagonist (1 or 10 mg/kg s.c., or at 10, 30 or 100 /~g/5 Izl i.c.v.), inhibited the mean arterial pressure response but not the heart rate response to footshock. In contrast, the MAP response to exogenous administration of norepinephrine was not inhibited by subcutaneous administration of losartan (10 mg/kg). Given at 100/~g/5/el i.c.v., the angiotensin ATe-selective receptor antagonist, PD 123319, did not reduce hemodynamic responses to electric stimulation. These results suggest that, in acute stress, endogenous angiotensin II facilitation of noradrenergic transmission is mediated through the angiotensin AT 1 receptor.
ISRAEL, A., M. TORRBS, M. CIERCO AND Y. BARBBLLA. Further evidence for a dopaminergic involvement... more ISRAEL, A., M. TORRBS, M. CIERCO AND Y. BARBBLLA. Further evidence for a dopaminergic involvement in the renal action of centrally administered atrial natriuretic peptide in rats. BRAIN RES BULL 27(S) 739-742, 1991. -Intracerebroventricular (ICV) administration of atria1 natriuretic peptide (ANP) induces an increase of urinary volume and sodium excretion in conscious male hydrated rats. The involvement of brain dopaminergic neurones in the ICV-ANP renal action was investigated. Diuretic and natriuretic action of ANP was prevented by inhibition of tyrosine hydroxylase activity with alpha-methyl-p-tyrosine treatment and was absent following selective central dopaminergic denervation with ICV administration of 6-hydroxydopamine in combina-
The aim of this study was to evaluate the effect of short-term administration of the AT 1 angiote... more The aim of this study was to evaluate the effect of short-term administration of the AT 1 angiotensin II receptor antagonists, eprosartan, on 10 the sympathetic response to cold pressor test (CPT) in normotensive healthy volunteers. Sixty-nine healthy volunteers were included in this 11 double-blind placebo-controlled study. Blood pressure and heart rate were determined before and 175min after oral administration of 12 placebo, losartan (50 mg) or eprosartan (600 mg). Immediately, the subjects underwent CPT and then the same hemodynamic variables were 13 measured. CPT increased arterial blood pressure (systolic, diastolic and mean) and HR in placebo-treated group. Pretreatment with a single 14 dose of losartan or eprosartan blunted CPT-induced pressor response, but not the rise in heart rate. Our results demonstrate that endogenous 15 angiotensin II, through stimulation of AT 1 receptor, supports sympathetic mediated stress-response in humans. 16 D
Footshocks increases mean arterial pressure and heart rate. Systemic or intracerebroventricular (... more Footshocks increases mean arterial pressure and heart rate. Systemic or intracerebroventricular (IVT) administration of losartan, a specific angiotensin AT1 receptor antagonist, not only inhibited the pressor response to footshocks but resulted in vasodepression. Peripheral or IVT administration of PD 123319, a specific angiotensin AT2 receptor antagonist, did not alter the haemodynamic response to footshocks. However, simultaneous blockade of angiotensin AT1 and AT2 receptors by combined systemic or central administration of losartan and PD 12319, eliminated the vasodepressor response to footshocks unmasked in losartan pretreated rats. Our data suggest that activation of peripheral or brain angiotensin AT2 receptor mediated the vasodepressor response to footshocks in the presence of angiotensin AT1 receptor antagonist. We studied the role of kinins and nitric oxide in the vasodepressor response observed after footshocks. The decrease in mean arterial pressure observed after footshocks in losartan treated rats was blunted by systemic or IVT administration of icatibant (HOE 140) or N(G)-nitro-L-arginine-methyl ester, indicating that peripheral or brain kinins and nitric oxide are involved in the hypotensor response to footshocks during angiotensin AT1 receptor blockade. Our results suggest a role for angiotensin AT2 receptor in the regulation of arterial blood pressure, possibly through the release of vasodilator autacoids such as bradykinins and nitric oxide.
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