Reference intervals for four biochemistry analytes in plasma for evaluating oxidative stress and lipid peroxidation in human plasma.
Explore the source record for details and available documents.
Adolescent↗
Biomedical subjects
L F Carbonell
Publications and source records attributed to L F Carbonell.
The NS2 polypeptide of parvovirus MVM is required for capsid assembly in murine cells.
Mutants of minute virus of mice (MVM) which express truncated forms of the NS2 polypeptide are known to exhibit a host range defect, replicating productively in transformed human cells but not in cells from their normal murine host. To explore this deficiency we generated viruses with translation termination codons at various positions in the second exon of NS2. In human cells these mutants were viable, but showed a late defect in progeny virion release which put them at a selective disadvantage compared to the wildtype. In murine cells, however, duplex viral DNA amplification was reduced to 5% of wildtype levels and single-strand DNA synthesis was undetectable. These deficiencies could not be attributed to a failure to initiate infection or to a generalized defect in viral gene expression, since the viral replicator protein NS1 was expressed to normal or elevated levels early in infection. In contrast, truncated NS2 gene products failed to accumulate, so that each mutant exhibited a similar NS2-null phenotype. Expression of the capsid polypeptides VP1 and VP2 and their subsequent assembly into intact particles were examined in detail. Synchronized infected cell populations labeled under pulse-chase conditions were analyzed by differential immunoprecipitation of native or denatured extracts using antibodies which discriminated between intact particles and isolated polypeptide chains. These analyses showed that at early times in infection, capsid protein synthesis and stability were normal, but particle assembly was impaired. Unassembled VP proteins were retained in the cell for several hours, but as the unprocessed material accumulated, capsid protein synthesis progressively diminished, so that at later times relatively few VP molecules were synthesized. Thus in NS2-null infections of mouse cells there is a major primary defect in the folding or assembly processes required for effective capsid production.
Amino Acid Sequence↗
Effect of N omega-nitro-L-arginine methyl ester on cardiac haemodynamic responses to adenosine infusion in conscious rats.
1. The aim of the present study was to evaluate the role of NO in the cardiovascular effects of adenosine in conscious rats. 2. Cardiac index was determinated by thermodilution. In a group of rats, three doses of adenosine were infused (i.v.) at a rate of 150, 300 and 450 micrograms/kg/min in the absence and in the presence of L-NAME (10 mg/kg). In a second group of rats, the experimental protocol was the same as that of the first group, except an infusion of methoxamine (50 micrograms/kg/min) was given during the second adenosine administration, instead of L-NAME. 3. In the absence of L-NAME or methoxamine, adenosine induced a dose-dependent decrease in mean arterial pressure and an increase in vascular conductance although adenosine did not affect cardiac index. 4. L-NAME administration attenuated the decreasing effect on the mean arterial pressure in response to the two lower doses of adenosine. In the presence of L-NAME, adenosine induced a significant increase in cardiac index from 18.7 +/- 1.5 to 29.1 +/- 1.9 and 26.2 +/- 1.4 ml/min/100 g. Administration of L-NAME significantly attenuated the adenosine-induced increase in vascular conductance. 5. Methoxamine infusion induced an enhanced response to adenosine infusion. In the presence of methoxamine, adenosine induced a significant greater decrease in mean arterial pressure, and increase in cardiac index and vascular conductance. 6. These results indicate that part of the cardiovascular effects of adenosine can be mediated by NO, since L-NAME administration partially blocked the adenosine-induced vasodilatation.
Adenosine↗
Role of nitric oxide and prostaglandins in the regulation of blood pressure in conscious rats.
The present study was designed to investigate the possible role of endothelium-derived vasodilators, nitric oxide and prostaglandins, in the regulation of blood pressure during the presence and absence of the major pressor systems. Conscious rats were infused with a cocktail of inhibitors of the sympathetic nervous system, renin-angiotensin system, and V1 vascular receptor to vasopressin (achieved with hexamethonium, captopril, phentolamine, propranolol, and the V1 vasopressin (AVP) antagonist des-(CH2)5Tyr(Me)-AVP). The cocktail of vasoconstrictor inhibitors induced a marked fall of mean arterial pressure (MAP) from 109 +/- 2 to 52 +/- 2 mmHg (1 mmHg = 133.3 Pa) (n = 24). In animals with blockade, the specific inhibitor of nitric oxide synthesis, NG-nitro-L-arginine methyl ester (L-NAME), induced a significant increase of MAP from 51 +/- 1 to 84 +/- 2 mmHg (n = 6). In the presence of indomethacin, a cyclooxygenase inhibitor, the pressor response to L-NAME was from 52 +/- 2 to 126 +/- 4 mmHg (n = 6). Neither indomethacin (n = 6) nor vehicle (n = 6) alone altered MAP. In intact animals without blockade, L-NAME caused a similar increase of MAP when it was injected alone (from 107 +/- 3 to 144 +/- 4 mmHg, n = 7) or with indomethacin (from 113 +/- 3 to 144 +/- 3, n = 6). Indomethacin alone (n = 8) did not change MAP. In conclusion, in the absence of the major pressor systems, the pressor effect of the inhibition of the production of endogenous nitric oxide and vasodilator prostanoid synthesis appears to be synergistic. These results suggest that these two endogenous vasodilators are involved in the maintenance of blood pressure.
Animals↗
Indomethacin does not modify the role of nitric oxide on blood pressure regulation of SHR.
1. The endothelium-dependent relaxation is impaired in spontaneously hypertensive rats (SHR) by the release of a vasoconstrictor prostanoid. We evaluated whether such a vasoconstrictor prostanoid is masking the vasodilatation induced by nitric oxide (NO). 2. For this we observed, in SHR, whether indomethacin (INDO) modified both the pressor response to the inhibition of NO biosynthesis with L-nitro-arginine methyl ester (L-NAME) and the acute hypotensive response to acetylcholine. 3. INDO did not modify basal mean arterial pressure (MAP), either the pressor response to L-NAME, or the depressor response to acetylcholine. 4. It shows that, in awake SHR, a vasoconstrictor prostanoid, did not seem to affect the acute regulatory function of NO on MAP.
Acetylcholine↗
Cardiovascular effects of angiotensin II and vasopressin in intact awake rats.
1. In this study we evaluated, in intact awake rats, the effects of angiotensin II (AII) and vasopressin (AVP) on venous tone to explain their different hemodynamic effects. 2. Cardiac index (CI) was measured by thermodilution. AII and AVP were infused at the doses adjusted to increase mean arterial pressure 25, 50 and 70% above baseline. Lower doses of AVP than AII were necessary to increase mean arterial pressure at the same levels. 3. To study whether the different effects of AII and AVP on CI may be explained by their different actions on the venous system, changes in venous tone were evaluated by measuring mean circulatory filling pressure (MCFP) and determining the pressure gradient for venous return (PGVR). 4. AVP induced a decrease in CI from 32.5 +/- 2.2 to 23.1 +/- 1.7 and 15.4 +/- 0.8 ml/min/100 g (P < 0.01) with the second and third level of increase in afterload respectively, whereas AII at the same levels of afterload decreased CI from 34.8 +/- 1.3 to 28.3 +/- 2.3 and 23.4 +/- 1.7 ml/min/100 g (P < 0.01). Furthermore, the rise in total peripheral resistances (TPR) was greater with AVP than with AII at the highest level of afterload (P < 0.05). Heart rate significantly decreased more in the animals infused with AVP than with AII. 5. There were no changes in MCFP and PGVR with either AII or AVP. 6. These results indicate that in intact awake rats the larger fall in CI induced by AVP can not be explained only by a greater decrease in HR since at highest levels of afterload AVP decreased SV.(ABSTRACT TRUNCATED AT 250 WORDS)
Angiotensin II↗
N-acetyl-L-cysteine potentiates depressor response to captopril and enalaprilat in SHRs.
Recently, in vivo and in vitro studies have implicated nitric oxide as a mediator of the vascular effects of angiotensin-converting enzyme inhibitors (ACEIs). In the present study we hypothesized that N-acetyl-L-cysteine (NAC), by increasing the availability of reduced sulfhydryl groups, would enhance the antihypertensive response to the ACEIs captopril and enalaprilat by a mechanism dependent on nitric oxide. The experiments were performed on instrumented, indomethacin-pretreated, awake spontaneously hypertensive rats (SHRs). Thirty minutes after a bolus of captopril (10 mg/kg iv) was administered, blood pressure decreased from 167 +/- 5 to 147 +/- 6 mmHg (n = 8). The pretreatment with the donor of thiol groups NAC (300 mg/kg iv) potentiated the depressor response to captopril because blood pressure decreased from 172 +/- 3 to 139 +/- 4 mmHg (n = 6). At the dose of 60 micrograms/kg iv, the ACEI enalaprilat did not acutely modify the blood pressure of SHRs (from 172 +/- 5 to 167 +/- 4 mmHg; n = 6). However, when the SHRs were pretreated with NAC, the same dose of enalaprilat significantly reduced blood pressure from 176 +/- 5 to 151 +/- 5 mmHg (n = 6). This potentiation of the depressor response to ACEIs, due to NAC, was not observed when SHRs were pretreated with the nitric oxide inhibitor NG-nitro-L-arginine methyl ester (L-NAME; 50 micrograms.kg-1.min-1 iv). The results of this study suggest that NAC, a donor of sulfhydryl groups, potentiates the antihypertensive response to captopril and enalaprilat in SHR by a nitric oxide-dependent mechanism.
Acetylcysteine↗
Increased total vascular capacity in conscious cirrhotic rats.
The purpose of the present study was to determine the role of the systemic venous circulation in the hemodynamic alterations of the cirrhotic disease. Cardiac output (thermodilution; n = 8), mean circulatory filling pressure (balloon technique; n = 6), and blood volume (Evans blue dye; n = 7) were investigated in a rat model of liver cirrhosis without ascites induced by a 12-week individualized CCl4/phenobarbital treatment. Compared with control rats, conscious cirrhotic rats showed a hyperdynamic circulation characterized by normotension, high cardiac output (51 +/- 4.8 vs. 28.6 +/- 1.3 mL.min-1.100 g-1; P less than 0.01), and expanded blood volume (6.5 +/- 0.15 vs. 5.4 +/- 0.22 mL.100 g-1; P less than 0.05). There were no significant differences between control and cirrhotic rats in mean circulatory filling pressure (6.40 +/- 0.27 vs. 5.99 +/- 0.22 mm Hg, respectively) or in the pressure gradient for venous return (6.17 +/- 0.19 vs. 5.8 +/- 0.21 mm Hg, respectively). To further examine the venous tone, effective vascular compliance was estimated with the vascular filling-blood volume relationship by measuring the vascular filling before and after rapid changes in volume (+/- 8 mL.kg-1). Compliance was similar in both control and cirrhotic rats (3.15 +/- 0.26 and 3.41 +/- 0.21 mL.mm Hg-1), but the vascular filling-total blood volume relationship of the cirrhotic rats was displaced toward the volume axis. In conclusion, the increase in blood volume without changes in mean circulatory filling pressure (or venous tone) of the cirrhotic rats indicates a situation with venodilation and elevated total venous capacity; this is likely to be an important mechanism that could explain the hyperdynamic circulation of the cirrhotic disease.
Animals↗
Cardiocirculatory responses to AII and AVP in conscious rats.
Cardiac and peripheral circulatory responses to changes in afterload with angiotensin II (AII) and vasopressin (AVP) were investigated in ganglion-blocked (hexamethonium) conscious rats. Cardiac output (CO) was measured by thermodilution. Both hormones were infused at a dose adjusted to increase mean arterial pressure 70% above baseline. AVP (11.4 +/- 2.2 ng/kg/min, n = 6) decreased CO from 43.4 +/- 2.3 to 34.1 +/- 2.9 ml/min/100 g (p less than 0.001), whereas AII (33.4 +/- 7.4 ng/kg/min, n = 7) increased CO from 38.7 +/- 2.6 to 44.9 +/- 3.4 ml/min/100 g (p less than 0.01). Heart rate did not change with the increase in afterload with either vasoconstrictor. To study whether the different effects of AII and AVP on CO may be explained by their different actions on the venous system, changes in venous tone were evaluated by measuring mean circulatory filling pressure (MCFP) and determining the pressure gradient for venous return (PGVR). AVP changed neither MCFP nor PGVR, whereas AII increased both these parameters, 20.7 +/- 2.8% (p less than 0.01) and 20.3 +/- 6.4% (p less than 0.01), respectively, above control. We also examined the effects of AII and AVP on ventricular dynamics: left ventricular systolic pressure and left ventricular dP/dtmax increased as aortic pressure was increased in a similar manner with both vasoconstrictors. However, AVP induced a greater increase in left ventricular end diastolic pressure than AII. Our results indicate that AII induces an increase in preload by its effect on venous tone, which is adequate to increase cardiac output. The decrease in cardiac output induced by increasing afterload with AVP can be explained by two mechanisms: an inadequate venous return and a failure of the left ventricle to overcome the increased afterload.
Angiotensin II↗
Limited cardiac preload reserve in conscious cirrhotic rats.
In conscious rats with experimental cirrhosis without ascites, we have studied whether there is a limited cardiac preload reserve by performing cardiac output (CO) curves. CO was determined by thermodilution at basal, 5, 7.5, and 10 cmH2O of right atrial pressure (RAP). RAP was elevated by dextran infusion (1 ml/min iv, 30 min). CO curves were performed by plotting changes in CO with changes in RAP. In the basal state, cirrhotic rats showed a hyperdynamic circulation defined by increased CO and stroke volume, decreased total peripheral resistances, and normotension without changes in heart rate. Blood volume was also elevated in cirrhotic rats compared with the control animals. Between the limits of RAP studied, the CO curve of control rats presented a typical ascending limb. In contrast, the CO curve of the cirrhotic animals showed first an ascending shifted upward limb and afterward a descending limb. These alterations were accompanied by changes in the inotropic state as measured as left ventricular (LV) peak dP/dt in hexamethonium-pretreated animals submitted to the same volume loads described above. With the same increases in RAP, LV dP/dt changed, in every group, in a manner similar to CO. The results of the present study indicate that cirrhotic rats with high blood volume and hyperdynamic circulation show, in the steady state, a limited preload reserve. The partial utilization of the preload reserve can make the cirrhotic heart unable to modulate cardiac performance with changes in loading conditions, thus determining a state of heart failure.
Animals↗
Hemodynamic effects of hypertonic saline in the conscious rat.
The present study examines the role of vasopressin and the sympathetic nervous system on the hemodynamic effects of an infusion of hypertonic saline (NaCl 1.5 M) in conscious rats. The cardiovascular response to hypertonic saline was similar in both untreated and hexamethonium-pretreated rats. Mean arterial pressure increased by 15 mmHg as a consequence of the elevation of total peripheral resistance, while cardiac index was decreased. The administration of an antagonist to the pressor activity of vasopressin in rats with intact reflexes, partially decreased mean arterial pressure and total peripheral resistance and increased cardiac index toward basal values. In contrast, the hemodynamic response to hypertonic saline was totally reverted when the vasopressin antagonist was injected in the hexamethonium-pretreated rats. The results of the present study indicate that the hypertensive response induced by hypertonic saline in conscious rats is due to the vasoconstrictor effects of both vasopressin and the sympathetic nervous system.
Animals↗
Synthesis of a gene coding for an insect-specific scorpion neurotoxin and attempts to express it using baculovirus vectors.
We have explored the possibility of improving baculovirus pesticides by incorporating an insect-specific neurotoxin gene into a baculovirus genome. A 112-bp gene (BeIt) encoding insectotoxin-1 of the scorpion Buthus eupeus was synthesized and cloned in Escherichia coli. For expression, BeIt was transferred to the DNA genome of Autographa californica nuclear polyhedrosis virus (AcMNPV). Three different recombinant AcMNPVs, carrying BeIt under the control of the strong AcMNPV polyhedrin promoter, were constructed and expression of BeIt was monitored upon infection of Spodoptera frugiperda (Sf) cells. Toxin expression was low using a recombinant virus in which BeIt was inserted 6 nucleotides (nt) downstream from the intact polyhedrin mRNA leader. More expression was observed when a signal-peptide was attached in-frame to the N terminus of BeIt. The highest level of expression was observed with a fusion gene comprised of the 58 N-terminal codons of polyhedrin fused to BeIt; however, the level of expression was ten- to twenty-fold below that for polyhedrin. Polyhedrin promoter-directed transcripts of all three recombinants accumulated to levels similar to those of wild-type polyhedrin transcripts, indicating that the limitation to expression of unfused BeIt was not at the level of transcription but rather at the posttranscriptional level including translation or protein stability. Paralytic activity of the toxin products was not detected.
Amino Acid Sequence↗
Effects of a kinin antagonist on mean blood pressure.
Administration of high doses of a kinin antagonist produces an increase in blood pressure. Thus, endogenous kinins may be involved in the regulation of blood pressure. Kinins can induce the release of vasoactive substances such as catecholamines, renin, vasopressin, histamine, and prostaglandins. To determine whether the blood pressure changes induced by high doses of kinin antagonist are due to agonistic activity mediated by these vasoactive substances, we studied the effect on blood pressure of a kinin antagonist (DArg0-Hyp3-Thi5,8-DPhe7-bradykinin) administered to control, nephrectomized, and adrenalectomized rats, and to rats treated with vasopressin V1-receptor antagonist, ganglionic and alpha- and beta-adrenergic receptor blockers (either separately or combined), histamine H1- and H2-receptor blockers, and indomethacin, a prostaglandin synthesis inhibitor. Blood pressure changes were monitored on awake, restrained rats. In the control rat, the kinin antagonist injected as a bolus (4 mg/kg) into the ascending aorta produced a transient biphasic blood pressure response, first a pressor effect (delta BP = 7 +/- 1 mm Hg; p less than 0.05), then a depressor effect (delta BP = -20 +/- 6 mm Hg; p less than 0.05). The pressor response to the kinin antagonist was not affected by any of the treatments; however, the depressor effect of the kinin antagonist appeared to be caused by the release of vasodilator prostanoids from the kidney, since it was not observed in the nephrectomized rats or in those treated with indomethacin. The pressor effect induced by the kinin antagonist suggests that kinins may contribute to the regulation of blood pressure.
Adrenal Glands↗
Effect of a kinin antagonist on the acute antihypertensive activity of enalaprilat in severe hypertension.
The purpose of this study was to assess the role of kinins in the acute antihypertensive effect of the converting enzyme inhibitor (CEI) enalaprilat in rats with severe hypertension induced by aortic ligation between both renal arteries. For this study, we used a bradykinin analogue, D-Arg-Arg-Pro-Hyp-Gly-Thi-Ser-DPhe-Thi-Arg-TFA, with in vivo antagonistic properties. Hypertensive rats were infused intra-aortically for 15 minutes with either saline (30 microliters/min) or the kinin antagonist (40 micrograms/kg/min). Five minutes after the infusion was begun, a bolus injection of enalaprilat (60 micrograms/kg) was given. The blood pressure of the saline-infused animals decreased 48 +/- 6 mm Hg (from 180 +/- 7 to 132 +/- 7 mm Hg), while that of the rats treated with the antagonist decreased only 21 +/- 4 mm Hg (from 175 +/- 3 to 154 +/- 3 mm Hg). The difference between both decrements was significant (p less than 0.01). In another group of hypertensive animals (n = 9), we measured kinin concentration in plasma from arterial blood before and after administration of CEI (41 +/- 10 vs 68 +/- 20 pg/ml, respectively; NS). These results are consistent with the hypothesis that kinins play a role in the acute antihypertensive effect of CEIs in rats with severe hypertension. However, since arterial blood kinin concentrations were not increased significantly after CEI administration, the effect of the CEI may be due to an increase in tissue kinins, which could act as autacoids regulating vascular resistance.
Angiotensin-Converting Enzyme Inhibitors↗
Baculovirus interaction with nontarget organisms: a virus-borne reporter gene is not expressed in two mammalian cell lines.
The safety of baculoviruses with respect to mammalian species was studied by using a genetically engineered recombinant of Autographa californica nuclear polyhedrosis virus. This recombinant contains the chloramphenicol acetyltransferase (CAT) gene under the control of a mammalian-active promoter and expresses substantial levels of CAT activity on infection of permissive and nonpermissive insect cells (L.F. Carbonell, M.J. Klowden, and L.K. Miller, J. Virol. 56:153-160, 1985). Extremely low levels of CAT activity were detected in mouse and human cell lines that were continuously exposed to the A. californica nuclear polyhedrosis virus recombinant. The appearance of CAT was not inhibited by cycloheximide. Isopycnic centrifugation of purified inoculum showed that a low level of CAT activity was associated with the insect-derived viral particles. Thus, the observed CAT activity is carried into the cells with the virus inoculum, and active expression of the baculovirus-borne CAT gene is not observed in either cell line. The inability of the CAT gene to be expressed in these cell lines with this model system provides additional assurance of the safety of insect baculoviruses with respect to mammalian species.
Acetyltransferases↗
Hemodynamic alterations in chronically conscious unrestrained diabetic rats.
Important cardiovascular dysfunctions have been described in streptozotocin (STZ)-diabetic rats. To determine the influence of these changes on the hemodynamic state and whether insulin treatment can avoid them, different hemodynamic parameters, obtained by the thermodilution method, were studied in STZ-induced (65 mg/kg) diabetic male Wistar rats, as well as in age-control, weight-control, and insulin-treated diabetic ones. All rats were examined in the conscious, unrestrained state 12 wk after induction of diabetes or acidified saline (pH 4.5) injection. At 12 wk of diabetic state most important findings were normotension, high blood volume, bradycardia, increase in stroke volume, cardiac output, and cardiosomatic ratio, and decrease in total peripheral resistance and cardiac contractility and relaxation (dP/dtmax and dP/dtmin of left ventricular pressure curves). The insulin-treated diabetic rats did not show any hemodynamic differences when compared with the control animals. These results suggest that important hemodynamic alterations are present in the chronic diabetic state, possibly conditioning congestive heart failure. These alterations can be prevented by insulin treatment.
Animals↗
Blood pressure control in pithed rat.
In the pithed Wistar rats Captopril (2 mg/kg) decreased the mean arterial pressure (MAP) 21%. Further injection of a specific antagonist decreased the vasoconstrictor action of vasopressin (aAVP, 10 micrograms/kg) an additional 6%. Reversal in the order of drug administration did not change these percentages. The osmotic stimulus evoked by the infusion of hypertonic saline (ClNa 9%, 0.018 ml/min, 2 hr) significantly increased MAP, this increase being almost totally reversed by the aAVP (10 micrograms/kg). These findings suggest a greater role of the renin-angiotensin system than of the vasopressin (AVP) in the maintenance of MAP in the pithed rat; AVP, moreover, can be released by means of an osmotic stimulus.
Animals↗
Dopamine-beta-hydroxylase activity in adrenal gland and spleen of rats after fasting and cold exposure.
Fasting (48 h) results in dopamine-beta-hydroxylase (DBH) release both in adrenal gland and spleen, suggestive of an increase in the activity of these organs. Cold exposure (48 h) produces a dissociation of the sympathoadrenal response. When both stimuli are simultaneously employed, the DBH response suggests the preponderance of the response to fasting. Plasma DBH is decreased in all groups studied, this could be due to its half-life and the splenic DBH depletion.
Adrenal Glands↗