Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of chronic ethanol ingestion on the rat kidney were studied. Rats were fed a liquid diet containing ethanol for 5 weeks to induce chronic alcoholism. Renal ischemia was introduced by clamping the renal artery and vein either for 10 or 20 min. The glomerular filtration rate (GFR) and the renal blood flow (RBF) were determined by using I125-iothalamate and I131-iodohippurate. In the absence of renal ischemia, there were no significant differences in the renal function between nonalcoholic rats (n = 5) and alcoholic rats (n = 5): 380 +/- 30 vs. 403 +/- 27 microliters/min/100 g body weight (BW) in GFR, and 3.1 +/- 0.1 vs. 3.1 +/- 0.2 ml/min/100 g BW in RBF. The recovery of GFR measured 2 h following 10-min renal ischemia in both groups was not significantly different; the values returned to 340 +/- 40 microliters/min/100 g BW (nonalcoholic rats) and 246 +/- 22 microliters/min/100 g BW (alcoholic rats), respectively. The changes of RBF following 10 min ischemia were also similar in both groups. However, the effects of alcoholism on the renal function became apparent when animals were subjected to more prolonged renal ischemia. In nonalcoholic rats (n = 5), GFR and RBF measured 2 h following 20 min renal ischemia were 245 +/- 51 microliters/min/100 g BW and 2.5 +/- 0.4 ml/min/100 g BW, whereas in alcoholic rats (n = 5) the GFR and RBF were significantly decreased to 93 +/- 15 microliters/min/100 g BW and 1.1 +/- 0.2 ml/min/100 g BW, respectively (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Nephron 1989
PMID:Kidneys of chronic alcoholic rats are more vulnerable to ischemic insult. 281 70

Regional levels of brain monoamines and their metabolites were examined in a rat model of reversible and diffuse forebrain ischemia with and without reperfusion. During ischemia, blood flow decreased by 87 to 95%, but recovered to control values during recirculation. Norepinephrine and serotonin decreased in the cerebral cortex and hippocampus during ischemia and diminished further during recirculation. On the other hand, dopamine and its metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid, which were not much affected by ischemia, increased markedly in the cerebral cortex and striatum during recirculation, with a decrease in the ratio of dopamine to its metabolites. These results suggest central dopaminergic hyperactivity during recirculation, which may be related to the selective vulnerability of the striatum in similar models of reversible forebrain ischemia.
 ...
PMID:Monoamine neurotransmitters in diffuse reversible forebrain ischemia and early recirculation: increased dopaminergic activity. 287 20

In essential hypertension ventricular function is determined primarily by the degree of hypertrophy (myocardial factor) and by the organic complications in the coronary artery (coronary factor). Ventricular function is inversely correlated with ventricular size and systolic wall stress, inasmuch as ventricular function diminishes when these two variables increase. Even the young hypertensive heart of normal size with no angiographic abnormalities appears to be prone to ischemia, because the coronary reserve is seriously limited even in the absence of coronary stenosis. Unlike ventricular distensibility, myocardial compliance may be normal even in the presence of pronounced myocardial hypertrophy. As myocardial compliance decreases, systolic wall stress increases and ventricular function is reduced. The hypertensive heart, the most common form of an irregular hypertrophy of the ventricular wall, is found in 14% of such cases. Analysis of the degree of hypertrophy shows that the hypertrophy can be inappropriately high (high mass-to-volume ratio, reduced wall stress), appropriate, or inappropriately low (normal mass-to-volume ratio, increased wall stress). Coronary reserve is reduced even in hypertensive hypertrophy without evidence of coronary artery disease. MVO2 per mass unit was directly correlated with systolic wall stress per cross-sectional area of the left ventricular wall. It is concluded that the appropriateness of left ventricular hypertrophy, as a result of mass-to-volume ratio and stress, is a major determinant of left ventricular performance, of coronary blood flow, and of myocardial oxygen consumption. Pharmacotherapeutical means of reversing cardiac hypertrophy (prazosin, clonidine, enalapril, and nifedipine) were analyzed in concentrically, as well as eccentrically, hypertrophied left ventricles. Regression of cardiac hypertrophy, i.e. therapeutic intervention on a critical precursor of hypertensive congestive heart failure, can be obtained by various antihypertensive agents. Prazosin, calcium channel blockers and angiotensin-converting enzyme inhibitors as well as a combined treatment regimen using alpha-receptor blockers together with diuretics and vasodilators can all induce regression of hypertrophy associated with an improvement in left ventricular function. Moreover, an improved coronary reserve may reduce the ischemic risk of the hypertrophied myocardium. However, not all antihypertensive drugs seem equally effective in bringing about coronary regression of left ventricular hypertrophy. No regression or little regression has been found with diuretic monotherapy despite a satisfactory reduction in blood pressure.(ABSTRACT TRUNCATED AT 400 WORDS)
Nephron 1987
PMID:Comparative analysis of cardiac function, geometry, energetics and coronary reserve in hypertensive heart disease. 296 4

Rats pretreated with sodium bicarbonate were functionally protected from the damage of bilateral renal artery occlusion. The rise in serum creatinine (day 1 minus day 0) during the first 24 h after ischemia was 2.88 +/- 0.28 mg% in the bicarbonate-loaded animals versus 3.90 +/- 0.26 mg% in their matched controls (p less than or equal to 0.01). Pretreatment with acetazolamide produced a similar alkaline urine as the bicarbonate loading (pH 8.3 vs. 7.0 in controls) and a similar degree of protection (delta creatinine 2.85 +/- 0.41 vs. 4.23 +/- 0.26 mg%; p less than or equal to 0.01). A direct effect of sodium loading was excluded by comparing NH4HCO3 with NaHCO3 loading and observing no difference in delta creatinine levels after ischemia (3.39 +/- 0.69 vs. 3.20 +/- 0.61 mg%). These data indicate that NaHCO3 protects in this model of acute renal failure and further suggest that the mechanism of protection is not related to either systemic alkalosis or sodium loading.
Nephron 1986
PMID:Effect of sodium bicarbonate preloading on ischemic renal failure. 301

We performed a study of hyperthermia while injecting 0.05% of Noradrenaline following MMC for 10 minutes into the feeding artery of Walker-256 carcinosarcomas implanted 6 days earlier into the s.c. dorsum side of hindpaw of Wistar rats. The tumor growth rates on the 6th day after treatment by warning tumor in hot water (40 degrees C, 44 degrees C) for 10 minutes with or without Noradrenaline, were 0.7 +/- 0.6, 2.1 +/- 0.9 (40 degrees C) and 0.2 +/- 0.3, 0.0 +/- 0.0 (44 degrees C), respectively. The data suggested that tumor ischemia induced by a vasoconstrictive drug may enhance the antitumor effect in low grade warning therapy (40 degrees C). An injection of warmed physiological saline (50 degrees C) may heat the tumor vessels on the tumor surface and showed enhanced antitumor effects as a from of hyperthermia. The target area of the tumor for hyperthermia can be considered to be the tumor vessels on the tumor surface.
 ...
PMID:[Enhancement of antitumor effect of MMC on Walker 256 by intra-arterial administration of noradrenaline in hyperthermia]. 313 74

The present work was performed on uninephrectomized rabbits recovering from ischemic acute renal failure (ARF) in an attempt to elucidate whether or not intraglomerular events are a determinant factor in the development of resistance to ARF. 14 days after a 2-hour clamping of the renal artery (the recovery phase), the animals did not show resistance to an additional ischemia. On the other hand, glomeruli derived from normal kidneys displayed a contractile response to angiotensin II, arginine vasopressin or norepinephrine in Eagle's minimum essential medium, whereas glomeruli from rabbits recovering from ischemic ARF were refractory to the vasoconstrictor agents. The findings suggest that glomerular refractoriness to contractile stimuli does not provide resistance to an additional renal ischemia in the ischemic model of ARF.
Nephron 1988
PMID:Glomerular refractoriness to contractile stimuli in rabbits recovering from ischemic acute renal failure. 336 77

Calcium-independent noradrenaline release was studied in the isolated perfused rat heart under conditions of normoxia, cyanide intoxication, and ischemia. The release of endogenous noradrenaline and dihydroxyphenylglycol were determined by high-performance liquid chromatography. The release of dihydroxyphenylglycol, the main neuronal noradrenaline metabolite, was used as an indicator of the free axoplasmic amine concentration. When storage function of neuronal vesicles was disturbed by Ro 4-1284 or trimethyltin, high dihydroxyphenylglycol release was observed without concomitant overflow of noradrenaline. If, however, these agents were combined with inhibition of Na+K+-ATPase or with veratridine-induced entry of sodium into the neuron, both dihydroxyphenylglycol and noradrenaline were released. Noradrenaline release was independent of extracellular calcium and was suppressed by blockade of neuronal catecholamine uptake (uptake1), indicating nonexocytotic noradrenaline liberation from the sympathetic nerve ending. This release critically depended on two conditions: 1) increased cytoplasmic concentrations of noradrenaline within the sympathetic neuron and 2) intraneuronal sodium accumulation. Both conditions together were required to induce noradrenaline efflux across the plasma membrane using the uptake1 carrier in reverse of its normal transport direction. A disturbed energy status of the sympathetic neuron, induced by cyanide intoxication or ischemia, likewise caused calcium-independent noradrenaline release by interfering with both vesicular storage function and neuronal sodium homoeostatis. Again, release was sensitive to uptake1 blockade. Since neuronal sodium accumulation was the rate-limiting step, release was further accelerated when residual Na+,K+-ATPase activity was inhibited. Na+-H+ exchange was identified as the predominant pathway of sodium entry into the sympathetic nerve ending in ischemia, and its inhibition by amiloride and ethylisopropylamiloride markedly suppressed ischemia-induced noradrenaline release.
 ...
PMID:Neuronal sodium homoeostatis and axoplasmic amine concentration determine calcium-independent noradrenaline release in normoxic and ischemic rat heart. 338 76

Prior acute renal failure (ARF) induced by either glycerol (G) or mercury provides protection against rechallenge with the same agent or the other. To ascertain whether the widely employed ischemic renal failure model also shares a similar pathogenesis, two protocols were designed. In the first protocol, unilaterally nephrectomized rats with or without a prior episode of G-induced ARF two weeks previously were subjected to an ischemic insult [60-min total left renal artery clamp (LRAC)]. At 24 or 48 h after LRAC there was no difference in renal function in the rats with or without prior ARF. In the second protocol the sequence of G and ischemia was reversed. In rats having undergone LRAC two weeks prior to G, glomerular filtration rate was virtually identical from the right (control) and left (prior ARF) kidney (right, 138 +/- 30; left, 101 +/- 22 microliter/min/100 g body weight), and not different from rats receiving G alone. We conclude that protection against ARF conferred by prior insult is not a feature of all models.
Nephron 1987
PMID:Protection against acute renal failure by prior acute renal failure: differences between myohemoglobinuric and ischemic models. 368 91

The levels and the turnover of noradrenaline were measured in the left and right ventricles following left coronary artery ligation for 2 h in untreated, adrenalectomized or hexamethonium-treated rats. Noradrenaline in the left ventricles was decreased by ligation and unaffected in the right ventricles, whether of untreated, adrenalectomized or hexamethonium-treated animals. Turnover in the left ventricles, as estimated by the decrease of noradrenaline under dopamine beta-hydroxylase inhibition with bis-(4-methyl-1-homo-piperazinyl-thiocarbonyl)-disulfide (FLA-63), was unaffected by ligation whether in untreated, adrenalectomized, or hexamethonium-treated rats. Ligation accelerated turnover in the right ventricles of untreated rats or attenuated it in adrenalectomized rats and caused no changes in hexamethonium-treated rats. These results suggest that noradrenaline turnover in ischemic myocardium is not affected by regional ischemia and that such ischemia might accelerate turnover in the non-ischemic area, probably as a result of increased activity of sympatho-adrenal reflexes.
 ...
PMID:Noradrenaline turnover after left coronary artery ligation in rat heart. 369 57

Changes in cerebral free amino acids, catecholamines and uric acid levels were explored for up to 7 days after cerebral ischemia in the rat. Fifty male Sprague-Dawley rats were subjected to occlusion of the middle cerebral artery on the olfactory tract, under halothane anesthesia. The animals were decapitated at 2, 4, 6, 12, 24 hours and 2, 3, 5, 7 days after the surgery, respectively. The brains were rapidly removed. The cerebral hemispheres were divided into right and left halves, and homogenized in sulfosalicylic acid solution. Free amino acids were analyzed by colormetric method. Cathecholamines and uric acid were analyzed by high-performance liquid chromatography. Each parameters were measured both on the ischemic and contralateral hemispheres. The time course of changes in each parameters were observed by means of the ratio, which is the value of ischemic side divided by that of contralateral side. Free amino acids Dicarboxylic group; Decreases in glutamate and increases in glutamine suggest one aspect of detoxication of ammonia within the ischemia tissue. Monocarboxylic group; GABA, glycine, alanine were increased in early ischemic state, and gradually lowered to the normal values. These suggest the impairment of tricarboxylic acid (TCA) cycle in the ischemic tissues, since these amino acids are closely related to TCA cycle. Essential amino acids, except for tryptophan, were increased until the end of study. These increases suggest the utilization of essential amino acids for protein synthesis might be disturbed in the ischemic tissues. Catecholamines and precursors; Norepinephrine and dopamine were lowered gradually. On the other hand, phenylalanine and tyrosine were increased during ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:[Biochemical studies of the cerebral ischemia in the rat--changes in cerebral free amino acids, catecholamines and uric acid]. 370 75


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>