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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of two diuretics, indapamide (3 mg/kg/day) and hydrochlorothiazide (20 mg/kg/day), were analyzed over a 44-day period on the cardiovascular hypertrophy of stroke-prone spontaneously hypertensive rats (SHR-SP). Untreated SHR-SP developed severe hypertension and cardiac hypertrophy when compared to normotensive Wistar-Kyoto (WKY) rats after 8 weeks on 1% sodium chloride. In diuretic-treated animals, systolic blood pressure was moderately decreased by the end of the treatment when compared with untreated SHR-SP (-13 and -18%, respectively, p < or = 0.05). Morphometric analysis of myocyte cross-sectional areas evidenced that indapamide was the most effective in preventing myocyte hypertrophy (-33%, p < or = 0.0001). Small coronary artery wall thickness was efficiently prevented in the two treated groups, but medial hypertrophy was prevented by hydrochlorothiazide only. Among markers of smooth-muscle cell phenotype (contractile or extracellular matrix proteins) EIIIA-fibronectin (FN), one FN cellular isoform, was shown to be the most sensitive marker by an immunohistochemical technic. Medial expression of EIIIA-FN, which was characteristic of SHR-SP coronary arteries, was prevented by the two treatments. The two diuretic treatments, despite similar effects on blood pressure and smooth-muscle phenotype, prevent SHR-SP cardiovascular hypertrophy with a drug-specific efficiency.
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PMID:Comparative effects of indapamide and hydrochlorothiazide on cardiac hypertrophy and vascular smooth-muscle phenotype in the stroke-prone, spontaneously hypertensive rat. 750 58

The question addressed in this study was whether a relation between myocardial lipid droplet accumulation and depressed myocardial function existed following intralipid infusion for 45 min in open chest, anaesthetized rabbits. One group of rabbits (n = 8) received intralipid infusion whereas a control group (n = 8) received sodium chloride. Local myocardial performance was obtained by sonomicrometry and the fractional volume of myocardial lipid droplets was measured by morphometric methods. The fractional volume of lipid droplets was 0.667 +/- 0.116% in the intralipid group compared with 0.318 +/- 0.080% in the control group (P < 0.03). Cardiac output and stroke volume fell 26% (P < 0.0001) and 34% (P < 0.0001), respectively, as a result of intralipid infusion. However, myocardial blood flow obtained by radiolabelled microspheres remained unchanged. Local myocardial function was reduced for both segments after intralipid infusion; maximal systolic shortening was reduced from 15.63 +/- 1.45 to 12.07 +/- 1.55% (P < 0.002) in the circumferential segment and from 9.46 +/- 1.17 to 7.40 +/- 0.53% (P < 0.05) in the longitudinal segment. The end-diastolic length of the circumferential segment was reduced by 3% (P < 0.05) after intralipid infusion. The reduced end-diastolic length of circumferential segments together with unchanged left ventricular end-diastolic pressure might indicate reduced left ventricular end-diastolic compliance. We conclude that acute intralipid infusion in rabbits results in myocardial lipid droplet accumulation and depressed local myocardial function.
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PMID:Intravenous lipid infusion results in myocardial lipid droplet accumulation combined with reduced myocardial performance in heparinized rabbits. 777 56

The contribution of chloride to the haemodynamic changes of salt-dependent deoxycorticosterone (DOC) hypertension was studied in young Wistar rats subjected to dietary loading with sodium chloride (NaCl) or sodium bicarbonate (NaHCO3). Mean arterial pressure (MAP), cardiac output, systemic resistance (TPR) and arterial rigidity (estimated from pulse pressure/stroke volume ratio, PP/SV) were determined in conscious chronically cannulated rats. DOC-induced increase of MAP and TPR appeared earlier in NaCl-loaded than in NaHCO3-loaded rats. After 4-6 weeks of hypertensive treatment MAP, TPR and PP/SV ratio were higher in DOC-treated rats fed NaCl diet than in those fed NaHCO3 diet. In contrast, after a long-term hypertensive regimen (lasting for 7-9 weeks) there was no significant difference in either MAP or TPR between rats loaded with NaCl or NaHCO3. On the other hand, DOC hypertension induced by a long-term feeding of NaHCO3 diet was not associated with an increase of arterial rigidity which was characteristic for DOC-NaCl hypertensive rats. Thus, a sufficiently long selective dietary sodium loading is capable to increase the systemic resistance but not to alter the arterial rigidity. This was also confirmed by a comparison of blood pressure-matched DOC hypertensive rats fed NaCl or NaHCO3 diets. These animals did not differ in the degree of systemic resistance elevation but the arterial rigidity was increased only in NaCl-loaded rats.
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PMID:Haemodynamic changes induced by short- and long-term sodium chloride or sodium bicarbonate intake in deoxycorticosterone-treated rats. 794 57

Several recent studies evaluated alkali therapy for lactic acidosis (LA). We studied the effects of sodium bicarbonate (NaHCO3) on LA due to hemorrhagic shock in dogs. After inducing hemorrhagic shock in twelve mongrel dogs, we divided them into two groups: the first group was treated with 7% NaHCO3 and the second with 4.9% sodium chloride (NaCl). We measured pyruvate, lactate, acetoacetate (AcAc) and 3-hydroxybutyrate (3OHBA) while monitoring hemodynamics and blood gases, and calculated pyruvate/lactate and AcAc/3OHBA ratios. There was no statistically significant difference between the two groups in hemodynamic parameters, except for stroke volume index, and oxygen consumption throughout this experiment. Arterial pH and base excess increased significantly in the NaHCO3 group. The increases of pyruvate and lactate were significantly greater in the NaHCO3 group than in the NaCl group, but the other metabolic data were not significantly different. We did not find that NaHCO3 had greater beneficial effect than NaCl in hemorrhagic shock model, and the use of NaHCO3 for LA due to hemorrhagic shock may not be recommended.
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PMID:[Effect of sodium bicarbonate on lactic acidosis in dogs with hemorrhagic shock]. 801 58

Increased dietary intake of regular salt (sodium chloride) interferes markedly with the therapeutic effects of angiotensin converting enzyme inhibitors. To study further the interactions between dietary salt intake and antihypertensive drug treatment, we examined the effects of felodipine, a dihydropyridine derivative Ca2+ channel antagonist with natriuretic properties, on blood pressure and the development of left ventricular hypertrophy in the stroke-prone spontaneously hypertensive rats during different levels of sodium chloride in the diet. We also compared the influence of regular salt on the cardiovascular effects of felodipine with that of a novel K(+)-, Mg(2+)- and l-lysine-enriched and Na(+)-reduced salt alternative, which in previous studies markedly improved the therapeutic effects of enalapril and ramipril. During the 28-day experiment regular salt produced a marked rise in blood pressure and induced left ventricular hypertrophy, while the salt alternative neither induced any rise of blood pressure nor caused cardiac hypertrophy. Felodipine had an enhanced antihypertensive effect during the increased intake of sodium chloride, and lowered the blood pressure to the same normotensive level as it did during the control and the salt alternative diets. Felodipine also completely blocked the development of the sodium chloride-induced cardiac hypertrophy. The heart rate of the felodipine-treated animals was significantly increased during the first two study weeks but thereafter it did not differ from that of the controls. Hence, unlike regular salt, the novel Na(+)-reduced, K(+)-, Mg(2+)-, and l-lysine-enriched salt alternative did not raise blood pressure and produced little if any left ventricular hypertrophy.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Cardiovascular effects of felodipine are not antagonized by dietary salt. 802 56

1. The influence of salt (sodium chloride; NaCl) (an additional 6% in the diet) and that of a novel sodium-reduced, potassium-, magnesium-, and L-lysine-enriched salt alternative on the cardiovascular effects of ramipril was studied in stroke-prone spontaneously hypertensive rats in a 6-week study. The intake of sodium chloride was adjusted to the same level by adding the salt alternative at a 1.75 times higher amount than regular salt. 2. Salt produced a marked rise in blood pressure and induced cardiac hypertrophy and significant mortality, while the salt alternative neither increased blood pressure nor caused any mortality and produced less cardiac hypertrophy than salt. 3. Ramipril treatment at a daily dose of 3 mg kg-1 normalized blood pressure and prevented the development of cardiac hypertrophy of rats on control diet. These effects of ramipril were blocked by the addition of salt but were only slightly attenuated by the addition of the salt alternative. The mortality in the salt group was prevented by ramipril. 4. Responses of mesenteric arterial rings in vitro were examined at the end of the study. Salt, but not the salt alternative, increased vascular contractile responses to noradrenaline. Ramipril treatment improved the arterial relaxation responses to acetylcholine and to sodium nitroprusside. The vascular relaxation enhancing effect of ramipril was blocked by salt but only slightly attenuated by the salt alternative. 5. Ramipril treatment did not significantly increase plasma renin activity in the presence or in the absence of salt supplementation. The salt alternative did not cause hyperkalaemia, either alone or in combination with ramipril treatment. 6. Both salt supplementations, irrespective of ramipril treatment, induced a six to eight fold increase in the urinary excretion of calcium. There was an expected 90 to 140% rise in the urinary excretion of magnesium and 200% rise in the urinary excretion of potassium in the salt alternative group. Salt also produced an approximately 50% increase in magnesuria.7. Our findings suggest that replacement of salt by the potassium-, magnesium- and L-lysine-enriched salt alternative improves the cardiovascular effects of ramipril. In the present study the beneficial effect was related to the increased intakes of potassium and/or magnesium and L-lysine from the salt alternative because the amount of sodium chloride was the same.
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PMID:Replacement of salt by a novel potassium- and magnesium-enriched salt alternative improves the cardiovascular effects of ramipril. 803 5

1. The influence of sodium chloride (NaCl)-enrichment of the diet (6% of the dry weight) and that of a novel sodium-reduced, potassium-, magnesium-, and L-lysine-enriched salt alternative on the cardiovascular effects of the beta 1-adrenoceptor blocking drug, metoprolol, was studied in stroke-prone spontaneously hypertensive rats. 2. Increased dietary sodium chloride intake produced a marked rise in blood pressure and induced left ventricular and renal hypertrophy. By contrast, the salt alternative did not increase blood pressure and caused remarkably less cardiac and renal hypertrophy than did sodium chloride. 3. Metoprolol treatment at a daily dose of 250 mg kg-1 lowered blood pressure and decreased left ventricular hypertrophy index during the control diet. Sodium chloride-enrichment blocked the antihypertensive effect of metoprolol, while a partial protective effect on left ventricular and renal hypertrophy persisted. In the presence of the salt alternative-enrichment both at the level of 6% and 10.5% (corresponding to a NaCl level of 6%), metoprolol was fully able to exert its beneficial cardiovascular and renal effects. 4. Both salt supplementations, irrespective of metoprolol treatment, induced a 3 to 4 fold increase in the urinary excretion of calcium. There was a linear correlation between the urinary excretions of sodium and calcium. The urinary excretion of magnesium rose by 90% and that of potassium by 110% in the salt alternative group. 6. Our findings suggest that replacement of common salt by a potassium-, and magnesium-enriched salt alternative in the diet produces beneficial cardiovascular effects and improves the antihypertensive efficacy of metoprolol in stroke-prone spontaneously hypertensive rats. Increased intake of potassium and/or magnesium and L-lysine from the salt alternative is involved in the beneficial effects of the salt alternative. The NaCl-induced myocardial and renal hypertrophies appear to be partially mediated by Beta-adrenoceptor activation.
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PMID:Improvement of cardiovascular effects of metoprolol by replacement of common salt with a potassium- and magnesium-enriched salt alternative. 807 82

Overwhelming hypoxic acidosis due to poor tissue oxygen delivery from low cardiac output, pulmonary failure, and other causes has devastating effects postoperatively on patient outcome. Whereas conventional therapeutics often can not reverse the downward spiral of these patients, dichloroacetate (DCA) has been shown to be beneficial. This study investigated the metabolic and hemodynamic effects of DCA given after the onset of overwhelming hypoxic acidosis in a canine model. A hypoxically ventilated canine model of severe induced acidosis was established and dogs surviving the development of acidosis were randomized to receive DCA or sodium chloride (NaCl) treatment. Dogs receiving DCA after development of hypoxic lactic acidosis showed no further change in metabolic parameters during the 90-minute treatment period (pH, 7.24 to 7.23; HCO3, 17.7 to 18 mmol/L; lactate, 2.04 to 1.05 mM/L); whereas animals receiving an equivalent sodium load showed progressive, significant deterioration in all parameters (pH, 7.24 to 7.12; HCO3, 16.8 to 13.2 mM/L; lactate, 2.05 to 3.55 mM/L). Myocardial blood flow was significantly increased by hypoxia in all dogs. Finally, cardiac output and stroke volume were significantly increased at 90 minutes by DCA versus control. Myocardial oxygen utilization efficiency (LV work/M VO2) was improved during DCA treatment. DCA, a carboxylic acid, increases pyruvate dehydrogenase activity, thereby enhancing lactate use a metabolic substrate. DCA had an ameliorative metabolic effect, and benefitted myocardial performance without a direct inotropic effect. DCA treatment appears to enhance myocardial performance on a metabolic and not primarily inotropic basis, does not increase the "cost" of myocardial work, and warrants further study.
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PMID:The use of dichloroacetate in the treatment of overwhelming hypoxic acidosis. 816 89

The objective of this study was to compare the in vivo effects of sodium bicarbonate (NaHCO3) and Carbicarb infusion on regional contractile performance and acid-base status in the setting of hypercarbic acidosis. Animals (N = 9) were anesthetized and paralyzed using sodium pentothal, halothane, and pancuronium bromide, and mechanically ventilated with an air-O2 mixture so that arterial PO2 was > or = 300 mm Hg. Following beta-adrenergic blockade, alveolar ventilation was gradually reduced over a 50-minute period to increase arterial PCO2 to 60 to 80 mm Hg. Each of the following solutions was then infused in consecutive order directly into the left anterior descending artery coronary artery for 15 minutes: (1) 8.4% NaHCO3 at 2 mL/min; (2) 5% sodium chloride at 2 mL/min, equivalent to NaHCO3 in osmolality; (3) 6.3% Carbicarb at 0.5 mL/min, equivalent to NaHCO3 in buffer capacity; and (4) 6.3% Carbicarb at 2 mL/min, equivalent to NaHCO3 in volume. Regional stroke work analog (ultrasonic dimension transducers), interstitial myocardial pH (Khuri electrode), coronary blood flow (doppler flow probe), and hemodynamic/metabolic variables (heart rate, blood pressure, arterial and coronary venous blood gases) were measured at 1, 5, 10, and 15 minutes during each infusion and 10 minutes after the infusion was discontinued, ie, at 25 minutes. Animals were allowed to recover for 45 minutes between interventions. Values at each time point were compared with baseline for statistical significance. Small reductions in interstitial myocardial pH (P < .05) and stroke work (P > .05) were observed within 1 minute of NaHCO3 administration. Both parameters increased significantly from baseline levels thereafter, ie, interstitial myocardial pH at 5 minutes and stroke work at 15 minutes. Infusion of Carbicarb invariably was associated with an increase (P < .05) in interstitial myocardial pH. Stroke work increased (P < .05) during low-dose Carbicarb administration, but infusion of the higher dose was accompanied by a biphasic response, ie, an increase (P < .05) from 0 to 5 minutes, followed by a gradual decrease that achieved statistical significance 10 minutes after termination of the infusion. End-diastolic length was inversely proportional to changes in stroke work, and coronary blood flow varied directly with changes in coronary venous Pco2. Myocardial O2 consumption decreased (P < .05) during Carbicarb infusion, but changes during NaHCO3 did not reach statistical significance. Our findings lend support to the hypothesis that intramyocardial pH determines myocardial function independent of CO2 production by buffer therapy.(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Sodium bicarbonate versus Carbicarb in canine myocardial hypercarbic acidosis. 834 53

The effects of Carbicarb, sodium bicarbonate, and sodium chloride on arterial blood gases, lactate concentrations, hemodynamics, and myocardial intracellular pH were compared in hypoxic lactic acidosis with controlled carbon dioxide elimination. Twenty-one young mongrel dogs were anesthetized, mechanically ventilated, and randomly allocated into one of three treatment groups. After hypoxic lactic acidosis was induced and maintained, 2.5 mEq/kg of one of the agents was infused over 30 min. Arterial blood gases, pH, lactate concentrations, and hemodynamic variables were measured immediately prior to the infusion of the agent and 30 min after the infusion was completed. With sodium bicarbonate administration, there was a significant increase in arterial PCO2 as compared to both Carbicarb or sodium chloride administration. With Carbicarb administration, there was a significant increase in arterial pH, base excess, and cardiac index, without a significant increase in arterial lactate concentration as compared to sodium bicarbonate or sodium chloride administration. Stroke volume index was also increased significantly with decreased heart rate. The data suggest that Carbicarb administration in hypoxic lactic acidosis improved hemodynamics compared with sodium bicarbonate or sodium chloride administration. The increased stroke volume and cardiac contractility appear to be due to improved myocardial intracellular pH.
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PMID:Carbicarb, sodium bicarbonate, and sodium chloride in hypoxic lactic acidosis. Effect on arterial blood gases, lactate concentrations, hemodynamic variables, and myocardial intracellular pH. 777 77


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