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

Longitudinal studies of large cohorts of patients with Raynaud's Phenomenon have addressed the predictors of developing a secondary disease. New insights have been reported into the pathogenesis of Raynaud's phenomenon and the consequences of ischemia. Studies have suggested that more than one defect may cause Raynaud's phenomenon, including increased alpha-2 sympathetic receptor activity on vessels, endothelial dysfunction, deficiency of calcitonin gene related peptide protein--containing nerves or some central thermoregulatory defect. The vasoconstricting and profibrotic cytokine endothelin-1 was found to be elevated in scleroderma but did not correlate with disease subset or with evidence of pulmonary hypertension. Oxidant stress is thought to be increased in scleroderma, causing tissue damage and provoking fibrosis. Treatment with infusion of prostacyclin for primary pulmonary hypertension was approved, paving the way for studies of secondary forms of pulmonary hypertension. Oral prostanoids are being tested for the treatment of Raynaud's phenomenon.
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PMID:Raynaud's phenomenon and other features of scleroderma, including pulmonary hypertension. 901 60

Ischemia is a common clinical event with potentially serious consequences. The major part of tissue damage occurs upon reperfusion and is mediated by activated neutrophils. Ischemia reperfusion injury is manifested by oedema and increased microvascular permeability. This study tested cardiopulmonary functions following 2 h of lower limb ischemia. Anesthetized dogs were randomized into three groups: nonischemic sham dogs (n = 4), ischemic control dogs (n = 8) and ischemic dogs pretreated with prostaglandin (PG)E1 (n = 8). In control animals, mean pulmonary artery pressure (mPAP) increased 1 min after declamping from 13.37 +/- 2.61 mmHg to 16.88 +/- 3.68 mm Hg (P < 0.05). Pulmonary microvascular pressure (Pmv) increased within 1 minute of reperfusion from 7.71 +/- 1.87 mm Hg to 10.54 +/- 3.71 mm Hg (P < 0.05). These changes are consistent with increased lung microvascular permeability. White blood cell count fell slightly but not significantly and lung histology showed leukosequestration in alveoli of 171 +/- 22 polymorphonuclear leukocyte (PMN)/10 high powered fields (HPF) in the ischemic control group compared with 121 +/- 56 PMN/10 HPF in the sham group (P < 0.05). Systemic arterial pressure, cardiac output, central venous pressure and pulmonary artery wedge pressure were unaffected. In animals pretreated with PGE1, mPAP and Pmv were unchanged during reperfusion. Lung histologic findings appeared normal and leukosequestration was not observed. PMN counts in alveoli showed 95 +/- 26 PMN/10 HPF, lower than in ischemic control animals (P < 0.05). These data indicate that lower limb ischemia during reperfusion leads to pulmonary hypertension and leukosequestration, PGE1 infusion is effective in limiting ischemia reperfusion injury.
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PMID:Ischemia and reperfusion injury: prevention of pulmonary hypertension and leukosequestration following lower limb ischemia. 905 20

The effects of chronic hypobaric hypoxia (CHH, 28 days, simulated altitude 5,500 m) on the cardiac expression of myosin heavy chain (MHC) and creatine kinase (CK) was studied in rat left (LV) and right (RV) ventricle. To separate the effects of hypoxia from its associated perturbations, anorexia and pulmonary hypertension (resulting in RV hypertrophy), CHH animals were compared with normoxic controls (C) and with rats restricted in food supply (pair fed, PF). In RV, the increased proportion of beta-MHC in CHH (20 +/- 3%) vs. C (7 +/- 2%, P < 0.01) and vs. PF (12 +/- 2%, P < 0.05) rats was mainly attributed to hypertension. In contrast, the higher beta-MHC of CHH (23 +/- 2%) vs. C (13 +/- 2%, P < 0.05) in LV was mainly ascribed to anorexia (PF = 21 +/- 3%, not significant). A major contribution of anorexia was also evidenced in the isozymic profile of CK; anorexia accounted for a 25% decrease in mito-CK specific activity in LV, whereas hypertension partly accounted for the threefold increase in BB-CK in RV. CHH specifically induced a twofold rise in LV BB-CK. This suggests that both the expression of slow myosin, improving the economy of contraction, and the changes in CK isozymic profile could provide a biochemical basis for the CHH resistance to ischemia.
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PMID:Adaptation of cardiac myosin and creatine kinase to chronic hypoxia: role of anorexia and hypertension. 913 52

Birth hypoxia, asphyxia and ischemia have often been thought to be major causes of early hearing loss or deafness. The purpose of the present review is to focus on the role of these particular factors for perinatal auditory disorders. On the whole, only a small proportion of neonatal hearing loss is caused by perinatal factors. The exact etiology of neonatal hearing loss in children with complicated deliveries is difficult to evaluate due to the large number of causative factors that might be involved. After reviewing the literature covering the past 15-20 years, it is not possible to say that we understand the relative importance of different factors and their interactions. However, in the majority of studies, birth asphyxia is not correlated with hearing loss in babies with complicated deliveries Prolonged artificial ventilation, the presence of severe hypoxic ischemic encephalopathy or persistent pulmonary hypertension are important factors. The brain is more susceptible to anoxia than the ear and both are more likely to be damaged after prolonged pre-, peri- and postnatal hypoxia-ischemia than pure hypoxia during delivery. Perinatal hypoxia is more likely to cause a temporary hearing loss than a permanent one. Preterm babies are more vulnerable than term babies. The total number of risk factors, e.g. medicated by total length of stay in the neonatal intensive care unit and length of artificial ventilation, is the best predictor of risk for hearing loss of perinatal origin. The similarities between hearing loss and cerebral palsy are pointed out; only 8% of the cases of cerebral palsy are considered to be caused by conditions during delivery.
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PMID:Perinatal asphyxia, hypoxia, ischemia and hearing loss. An overview. 918

Plasma L-arginine is usually deficient immediately after hepatic reperfusion in orthotopic liver transplantation, which may also contribute to the occurrence of either hepatic ischemia-reperfusion injury or pulmonary hypertension. In this study, exogenous L-arginine was thus experimentally used to reverse the deficient status of the L-arginine/NO pathway. An in vivo model of 1 hr hepatic ischemia and reperfusion was thus tested in both rats (Experiment A) and pigs (Experiment B). In Experiment A, 10 mg/kg of L-arginine (group 1, n = 7), D-arginine (group 2, n = 7), or saline (group 3, n = 7) was administered through the portal vein. The hepatic tissue blood flow, at 20 min after reperfusion, improved in group 1 (70.7 +/- 7.0% of the preclamp levels) compared to groups 2 and 3. The serum glutamate oxaloacetate transaminase levels at 24 hr after reperfusion were also lower in group 1 (320 +/- 22.2 IU/L) than in either group 2 or group 3. The intrahepatic NO levels showed a temporal burst (> 15,000 pA current) after reperfusion only in group 1. In Experiment B, 10 mg/kg of L-arginine (group 4, n = 5), D-arginine (group 5, n = 5), or 10 ml of saline (group 6, n = 5) was administered through the portal vein. In group 4, the MPAP (mean pulmonary arterial pressure)/MAP (mean arterial pressure) was lower than that observed in groups 5 and 6. In conclusion, exogenous L-arginine administered from the portal vein was thus found to be effective in mitigating both portal hypertension and reperfusion injury by producing an increased amount of NO immediately after reperfusion.
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PMID:Role of exogenous L-arginine in hepatic ischemia-reperfusion injury. 922 19

It has already been shown that pulmonary injury is induced after intestinal or hind limb ischemia-reperfusion injury. The purpose of this study was to determine the effect of renal ischemia-reperfusion injury on the pulmonary system. We compared the pulmonary effects of 60 and 90 minutes ischemia followed by 24 hour reperfusion in sheep kidneys. Standard hemodynamic measurements, arterial and mixed venous blood gas analysis, urine output, creatinine clearance, and blood urea nitrogen concentration were measured at baseline, during ischemia and reperfusion periods. After 24 hours of reperfusion, animals were sacrificed and underwent autopsy with collection of samples for wet/dry lung-weight ratio, lung tissue conjugated dienes, and renal histology. As expected, renal ischemia resulted in an increased serum creatinine and blood urea nitrogen concentrations, decreased creatinine clearance, and histological evidence of renal damage. There was no evidence of pulmonary hypertension or hypoxemia during renal ischemia-reperfusion. There was also no significant difference in the wet/dry lung-weight ratios or lung tissue conjugated denies between the two ischemic groups (60 and 90 minutes) and nonischemic control group. These results suggest that renal ischemia-reperfusion injury was not associated with a significant degree of pulmonary dysfunction.
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PMID:Renal ischemia-reperfusion injury does not induce pulmonary dysfunction in sheep. 925 13

Inhibition of nitric oxide (NO) production may reduce post-hypoxic-ischemic (HI) neonatal brain damage, but may also induce pulmonary hypertension by inhibiting endogenous NO production in the pulmonary vascular bed. The aim of this study was to evaluate the effect of nitric oxide inhibition on pulmonary artery pressure and oxygen need after hypoxic ischemia. Severe HI was produced in 18 newborn lambs. After completion of HI the lambs were divided into three groups of 6 animals receiving either placebo (Cont), low dose N omega-nitro-L-arginine (10 mg/kg i.v., NLA-10) or high dose (40 mg/kg i.v., NLA-40) to block NO production. Pulmonary artery pressure (Pap), aortic pressure, blood gases, inspiratory oxygen concentration and ventilator settings were recorded before and 15, 60, 120 and 180 min after HI. Mean Pap rose initially significantly as compared to baseline in all groups at 15 min post-HI, decreased to normal in Cont but not in treated animals; 180 min post-HI mean Pap was significantly higher in both treated groups as compared to control (NLA-10: 32 mm Hg, NLA-40: 34 mm Hg, Cont: 25 mm Hg, p < 0.05 for NLA-10 and NLA-40 vs. Cont). Moreover, in both NLA-treated groups the oxygenation index was significantly elevated 120 and 180 min post-HI as compared to those of the Cont group. NO synthase inhibition after HI causes a prolonged increase in pulmonary artery pressure leading to a higher oxygen need.
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PMID:Nitric oxide inhibition after hypoxia-ischemia elevates pulmonary arterial pressure and increases oxygen need. 933 94

We investigated the long-term efficacy and the contraindications of single-session percutaneous ethanol injection (PEI) under general anesthesia in hepatocellular carcinoma (HCC). One hundred patients were treated from October, 1991, to April, 1996: 24 patients had a single capsulated HCC, 4.5 to 10 cm phi (group A); 62 had a single infiltrating tumor or multiple lesions (3 to 6), with 10 cm maximum phi (group B); 14 patients were in an advanced stage because of Child class C or of infiltrating tumors with portal thrombosis, with 14 cm lesion maximum phi (group C). Group A patients were treated because they were not operable or refused surgery. Three to 22 injections were performed (mean: 13) depending on tumor size and ethanol spread. The maximum injected volume of ethanol was 190 ml (mean: 57 ml). The procedure took 20 to 50 minutes (mean: 30 minutes). The mean hospital stay was 3.5 days. Tumor necrosis was complete in 58% of encapsulated tumors and > 70% in infiltrating lesions. The greatest lesion with complete post-PEI necrosis was 8.2 cm phi. A transient and variable increase in transaminase, bilirubin, white cell and D-dimer levels and a decrease in red cell, platelet, hemoglobin, fibrinogen and haptoglobin levels were observed. These changes were due to hepatic cell necrosis, hemolysis and focal thrombosis. One death (bleeding esophageal varices in the Child C patient)(1%) and four major complications (one peritoneal bleeding, one liver decompensation, two chemical segmentectomies with pain)(4%) were observed. 1, 2, 3 year survival rates for groups A, B and C were: 80, 63, 63%; 70, 50, 30% and 58, 14 and 0% respectively. In our experience, PEI was an efficacious procedure. The risk conditions are: superficial lesion site with severe coagulation defects, severe portal and/or pulmonary hypertension, esophageal varices at risk of bleeding, cardiac ischemia, advanced cirrhosis.
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PMID:[Single-session alcohol administration for hepatocarcinoma]. 942 44

Biophysical factors have been implicated in the development of pulmonary ischemia-reperfusion injury. In isolated rabbit lungs, the impact of vascular and alveolar distension, with and without alveolar oxygen supply, was investigated. With interruption of both perfusion (zero intravascular pressure) and ventilation, reperfusion after 120 min of warm ischemia resulted in transient pulmonary hypertension, with largely unchanged microvascular pressures, followed by a dramatic leakage response with approximately 10-fold increased capillary filtration coefficients (Kfc) and severe edema. Maintenance of vascular distension during ischemia (intravascular pressure of approximately 2 to 3 mm Hg) reduced the hypertension and fully suppressed the leakage. Employing ischemic periods of 180 and 240 min, ventilation of the lungs with 21 or 100% oxygen > ventilation with nitrogen during perfusion stop, but not static anoxic inflation, further enhanced the protective effect of vascular distension. At optimal biophysical support (vascular distension and ongoing normoxic ventilation), even 240 min of warm ischemia was tolerated with only moderate Kfc increase. We conclude that biophysical factors exert marked influence on pulmonary ischemia-reperfusion injury. Maintenance of vascular distension possesses strong protective potency, further enhanced by continued ventilation and alveolar oxygen supply during ischemia. These results may have important implications for organ preservation in lung transplantation.
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PMID:Vascular distension and continued ventilation are protective in lung ischemia/reperfusion. 944 96

Mechanical assisted circulation by the means of cardiac assist devices is a routine procedure in modern cardiac surgery and cardiology. We investigated the impact of mechanical unloading on regional myocardial "stunning" and the influence of assisted circulation on left heart and right heart failure persevered by an ultimate addition of pulmonary hypertension in experimental set ups. We found that mechanical unloading either during ischemia or in the early reperfusion phase attenuates stunning and enhances the return of synchronous heart performance. In our global dysfunction model we showed that the right heart is dispensable. Sufficient inflow to the left heart is provided unless pulmonary hypertension is present. Also additional left heart support can not overcome the deleterious situation and in select cases only additional right heart support can prevent the "low LVAD output" syndrome. We conclude that mechanical assisted circulation and mechanical unloading are beneficial in case of regional and global dysfunction persevered by pulmonary hypertension, however, the knowledge about interactions of assist systems and the circulation has to be improved in order to optimize clinical assist device performance.
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PMID:Pathophysiological considerations concerning uni- and biventricular mechanical cardiac assist. 950 83


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