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)

We evaluated effluent blood from extremities of human patients undergoing reconstructive surgical treatment, which is routinely accompanied by upper-extremity exsanguination and application of a tourniquet, resulting in total interruption of arterial blood flow to one upper extremity. After tourniquet release (reperfusion), there were immediate increases in the plasma levels of xanthine oxidase activity, uric acid, and histamine in the ipsilateral limb and much smaller increases, if any, in levels of the same materials in plasma obtained from the contralateral extremity. There was no detectable xanthine dehydrogenase activity in plasma from either limb. Plasma also contained evidence of products consistent with the formation of oxygen-derived free radicals, namely, the appearance predominantly in the reperfused limb of hemoglobin and fluorescent compounds. These data indicate for the first time in humans that ischemia-reperfusion events are associated with the appearance of xanthine oxidase activity and its products in the plasma effluent.
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PMID:Ischemia-reperfusion in humans. Appearance of xanthine oxidase activity. 231 21

Unpurified stroma-free hemoglobin (SFH) from water-lysed human red blood cells, hemoglobin Ao (HbAo), and hemoglobin cross-linked between alpha chains with 3,5-bis-dibromosalicyl-fumarate (HbXLDBBF) were infused into isolated perfused rabbit hearts. Vasoactivity and myocardial performance were determined using an isovolumic Langendorff preparation. With constant coronary flow, infusion of SFH (55 mg/dl) resulted in a 56% increase in aortic pressure as opposed to 29% and 11% increases with HbAo and HbXLDBBF, respectively. Rates of aortic pressure increase were over 6 times greater with SFH than with either HbAo or HbXLDBBF and exhibited concentration dependence only with SFH. Myocardial function remained normal. With constant coronary pressure, coronary flow decreased by 36% with SFH accompanied by a 23% decline in left ventricular developed pressure indicative of ischemia. With HbAo or HbXLDBBF, coronary flow decreased by only 1/3 that with SFH, while developed pressure declined by 4% and 2% with HbAo and HbXLDBBF, respectively. These data suggest that purification of HbAo to a single component can eliminate the dominant of at least two distinct vasoactive factors normally found in SFH. Furthermore, the physiological significance of the vascular response to HbAo is minimal. Preparations of HbXLDBBF accomplish this same result.
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PMID:Coronary vasoconstrictor activity of purified and modified human hemoglobin. 236 50

Clinical studies have demonstrated the efficacy of submucosal epinephrine injection in the control of bleeding ulcers. Since endoscopic techniques for assessing gastroduodenal blood flow are limited, we employed an animal model to study the mechanism of control of bleeding. The effect of submucosal epinephrine injection on local gastric blood flow was studied in the rat using laser Doppler flowmetry and reflectance spectrophotometry. Submucosal injection of 0.1 ml of 1/10,000 epinephrine caused a significantly greater drop in local gastric blood flow (laser Doppler flowmetry) compared with vehicle (10% sodium metabisulfite) injection. The reduction persisted for up to 120 min. This vasoconstrictive effect of epinephrine was confirmed by observations with reflectance spectrophotometry, which documented a pattern of ischemia without congestion (lower index of hemoglobin concentration, lower index of oxygen saturation). The autoregulatory escape from adrenergic vasoconstriction was not evident in either instance. We conclude that, after submucosal injection of epinephrine, the absence of autoregulatory escape from adrenergic vasoconstriction and the marked and prolonged decrease in local gastric blood flow enhance the homeostatic mechanisms (eg, platelets and other coagulative factors) to effect hemostasis in bleeding ulcers.
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PMID:Effect of submucosal epinephrine injection on local gastric blood flow. A study using laser Doppler flowmetry and reflectance spectrophotometry. 238 31

Oxygen affinity of hemoglobin, erythrocyte 2,3-diphosphoglycerate (DPG) and adenosine triphosphate (ATP) concentrations were compared before and after oral administration of vinpocetine (TCV-3B) (15 mg/d), a primarily vasodilating agent, for three weeks in eight patients with vascular dementia of the Biswanger type which is characterized by diffuse myelin pallor and multiple lacunes in the cerebral white matter. After vinpocetine administration, oxygen affinity of hemoglobin (P50) was significantly increased (26.5 +/- 0.55 to 27.6 +/- 0.62 mmHg; mean and standard deviation, p less than 0.05), red blood cell (RBC) ATP concentrations were significantly increased (846 +/- 168 to 1,158 +/- 130 mumol/l RBC, p less than 0.05), while DPG concentrations were unaltered (4.46 +/- 0.48 to 4.59 +/- 0.57 mmol/l RBC). There was a significant positive correlation between the increase of P50 and the increase of erythrocyte ATP concentrations (r = 0.67, p less than 0.05). The effect of vinpocetine of enhancing oxygen release of hemoglobin may offer an additional benefit to its primary vasodilating action in the treatment of vascular dementia of the Binswanger type due to chronic ischemia.
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PMID:Effect of vinpocetine on oxygen release of hemoglobin and erythrocyte organic polyphosphate concentrations in patients with vascular dementia of the Binswanger type. 239 97

With the technique of laser-Doppler velocimetry, cutaneous blood flows in the forearm of patients with stable sickle cell disease after graded periods of proximal ischemia were compared with normal subjects matched for age, race, and sex, and with patients with anemia caused by beta(+)-thalassemia. In the sickle cell patients the reactive hyperemia was characterized by an increased time interval between the release of the occlusion and the peak amplitude response (time-to-peak) and by a greater period of blood flow above the base-line value (payback ratio) compared with controls. In addition, prolongation of the occlusion period led to an augmentation in the magnitude of the characteristic basal flow oscillations or an induction of this phenomenon at sites not exhibiting it before ischemia. Base-line or ischemia-provoked flow oscillations of either this magnitude or frequency were only observed in normal or thalassemic controls during brief intervals in the rapidly decaying portion of the hyperemic response and in one subject with homozygous hemoglobin C disease. These results would support a model of a local integrative control of microcirculatory blood flow, which appears to become augmented, synchronized, and sustained in sickle cell subjects.
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PMID:Microcirculatory adaptations in sickle cell anemia: reactive hyperemia response. 240 12

Sickle cell retinopathy in its advanced form is complicated by preretinal neovascularization, vitreous hemorrhage, and retinal detachment. Treatment of neovascularization can be performed with photocoagulation. Complications such as retinal breaks, retinal detachments, and choroidally fed neovascularization may result from such treatment. The risks vs. the benefits of various types of photocoagulation are currently being evaluated. Cryotherapy also may be used to treat neovascularization. It is currently being used in eyes with media that are too hazy to permit photocoagulation. It is used commonly during scleral buckling and vitrectomy procedures. In eyes with decreased visual acuity secondary to prolonged vitreous hemorrhage, pars plana vitrectomy can be utilized to produce optically clear media. Complications (including erythrocyte-induced glaucoma), however, may be severe. Retinal detachment can be treated by scleral buckling, but the markedly increased risk of anterior segment ischemia in patients with sickle cell hemoglobin necessitates preoperative, intraoperative, and postoperative prophylactic measures to minimize the risk of this potentially devastating complication. In eyes with retinal detachment with cloudy media and severe vitreous traction, combined scleral buckling and vitrectomy may be necessary. These eyes are extremely fragile, and a successful result is currently obtained in only about 50% of such cases. Hyphemas in patients with sickle cell hemoglobinopathies, whether traumatically or surgically induced, may have devastating effects on the eye. If elevated IOP results decreased vascular perfusion of the eye may cause irreversible damage to the retina and optic nerve. Most antiglaucoma medications, when used in the sickle cell patient, have a narrow margin of safety. Therefore, early surgical intervention for the treatment of sickle cell hyphemas is currently being evaluated.
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PMID:Diagnosis and management of ocular complications of sickle hemoglobinopathies: Part V. 242 44

40 patients with ischemic heart disease were studied. In 60% of them a higher content of HbA2 was found. These data for higher frequency of HbA2 among the patients with ischemic heart disease do not correspond with the average incidence of the genetically determined anomaly A2-beta-thalassemia among the Bulgarian population. The negative data for increased methemoglobin, the shift of the oxygen dissociation curve to the right toward increased oxygen release from the hemoglobin molecule, the normalization of HbA2 after several days, the lack of anomalous fraction in the analyses lead to the conclusion that HbA2 plays a compensatory role in patients with ischemic heart disease and its dynamic changes could be used as a diagnostic test for ischemia.
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PMID:[Changes in the hemoglobin A2 level of patients with ischemic heart disease]. 247 9

Mental disability, variables associated with it and predictors of mental disability in late life were studied in 716 men from eastern and southwestern Finland in connection with the 25-year follow-up of the east-west study, which formed the Finnish part of the seven-countries study. The examinations were carried out in autumn 1984, when the men were 65-84 years of age. According to a 10-item mental status questionnaire, 95% of the men had normal mental capacities. There were no differences between the 2 areas. Old age, low educational level, low functional capacity, low body mass index, low serum cholesterol, low diastolic blood pressure, low alcohol or coffee consumption, low hemoglobin, low serum calcium, low serum triiodothyronine, high scores on the Zung Self-rating Depression Scale, and presence of transient ischemia or stroke were associated with mental disability in 1984. In the prospective analysis, low forced vital capacity, low forced expiratory volume in 0.75 s and high blood pressure in middle age predicted mental disability in old age.
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PMID:Mental disability among elderly men in Finland: prevalence, predictors and correlates. 259 44

The combination of continuous light spectrophotometry (CWS) and time resolved spectrophotometry (TRS) afford for the first time a quantitation of the optical path and the concentration changes detected by the CWS instrument. The application of these two techniques and magnetic resonance spectroscopy (MRS) to muscle during exercise affords a correlation of the biochemical activation and the response of the peripheral circulation (NRS) to the exercise stress (MRS). In preliminary experiments, the well-trained endurance performance limb shows a near perfect homeostasis to exercise stress while ischemia will cause a significant deoxygenation and an impairment of the work output. The use of this device in evaluation of peripheral vascular disease is obvious and hemoglobin deoxygenation may well occur at work levels less than those at which the diseased limb is capable.
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PMID:Time resolved spectroscopic (TRS) and continuous wave spectroscopic (CWS) studies of photon migration in human arms and limbs. 278 47

Using isolated hemoglobin-free perfused rat livers we studied the effect of low oxygen supply on ethanol hepatotoxicity in two models. In the first model resembling low blood supply, perfusion rate was lowered from 60 to 10 ml/min after a 30 min-equilibration phase and kept low for 60 min. As a consequence, oxygen consumption fell from 1.76 +/- 0.15 mumol/min/g to 0.51 +/- 0.02 mumol/min/g. In the second model, total ischemia was accomplished by interruption of the perfusion for 30 min and was followed by reperfusion at a perfusion rate of 60 ml/min for a further 30 min. In this model, oxygen consumption returned immediately to normal values upon reperfusion. In both models, low oxygen supply had no toxic effects of its own on livers from fed rats. While ethanol (3 g/l) given under normoxic conditions led to a moderate hepatotoxicity, its application in both models of partial as well as total ischemia and reperfusion resulted in a marked liver damage as evidenced by a strong release of sorbitol dehydrogenase, glutamate-pyruvate-transaminase, lactate dehydrogenase and glutathione, as well as by an increase in hepatic calcium content. Inhibition of ethanol metabolism by 4-methylpyrazol prevented liver damage in both models indicating that metabolism of ethanol is a prerequisite for its toxicity to occur. Also, hepatotoxicity was inhibited partially by catalase and superoxide dismutase and nearly totally by deferrioxamine and allopurinol. Thus, reactive oxygen species which are produced during ethanol metabolism as well as under conditions of low oxygen supply are mediators of hepatic damage in both models employed.
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PMID:Enhancement of acute ethanol hepatotoxicity under conditions of low oxygen supply and ischemia/reperfusion. The role of oxygen radicals. 281 46


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