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)

Ischemia may invalidate hormone-receptor analyses. This study determined the effects of progressive ischemia on steroid hormone-receptor analyses. Breast cancer was induced in 50- to 60-day-old female Holtzman rats by intragastric administration of 25 mg of 7,12-dimethylbenz[a]anthracene. After 90 days, rats were anesthetized and breast tumors were devascularized in vivo. At 0, 30, 60, 90 and 150 minutes, a biopsy specimen from each tumor was taken and rapidly frozen. Steroid binding capacity for estrogen (ER), progesterone (PR), and androgen (AR) receptors was determined by incubation with tracer receptor ligand. Ischemia decreased ER and AR levels by 30 minutes, whereas PR levels were unchanged through 150 minutes of ischemia. Following mastectomy, tylectomy, or breast biopsy, PR may be the most reliable of the hormone receptors for determining endocrine-responsive breast cancer. However, for accurate determination of all hormone receptors, specimens should be frozen in liquid nitrogen immediately, then preserved at -70 degrees C, or processed immediately.
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PMID:Lability of steroid hormone receptors following devascularization of breast tumors. 253 31

The nitroxide OXANO. (2-Ethyl-2,5,5-trimethyl-3-oxazolidinoxyl) which in its reduced form, OXANOH (2-Ethyl-1-hydroxy-2,5,5-trimethyl-3-oxazolidine), is capable of reacting with short-lived radicals, forming a secondary stable radical, was used for ESR-detection of radical production in isolated cells. The properties of OXANO. and OXANOH in terms of stability in cellular and subcellular systems, membrane permeability and effects on cellular viability were evaluated. Ischemia and reperfusion was simulated in vitro in a preparation of cells from rat intestinal mucosa by incubation at high density (4 X 10(8) cells/ml) under an atmosphere of nitrogen for 25 min and resuspended with fresh oxygenated buffer containing 5 mM OXANOH. A significant increase in radical formation during the 15 min reperfusion period studied was obtained in cells exposed to ischemia compared to control cells incubated at normal density under an atmosphere of oxygen. The addition of 5 microM of the scavenging enzyme superoxide dismutase reduced the radical formation by 50%. The time sequence of the superoxide formation was calculated as the difference in radical production in the presence and absence of superoxide dismutase.
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PMID:Detection of oxygen radicals during reperfusion of intestinal cells in vitro. 254 49

Electron paramagnetic resonance spectroscopy has been applied to measure radical generation in the postischemic heart; however, there is controversy regarding the methods used and the conclusion as to whether radicals are generated. In order to resolve this controversy, direct and spin trapping measurements of the time course and mechanisms of radical generation were performed in isolated perfused rabbit hearts. In reperfused tissue, 3 prominent radical signals are observed: A, isotropic g = 2.004 suggestive of a semiquinone; B, anisotropic g parallel = 2.033 and g perpendicular = 2.005 suggestive of ROO.; and C, a triplet g = 2.000 and aN = 24 G suggestive of a nitrogen centered radical. B and C, however, are highly labile and disappear at temperatures probably encountered in some previous studies. In normally perfused hearts, A is observed with only small amounts of B and C. During ischemia, B and C increase reaching a maximum after 45 min while A decreases. On reflow with oxygenated perfusate all 3 signals increase. With varying duration of ischemia and reflow, peak signal intensities occurred after 15 s of reflow following 30 min of ischemia. Reperfusion with superoxide dismutase, deferoxamine, or mannitol abolished the reperfusion increase of B. Measurements performed with the spin trap 5,5'-dimethyl-1-pyrroline-N-oxide (DMPO) demonstrated a similar time course of radical generation with prominent DMPO-OH and DMPO-R signals peaking between 10 and 20 s of reflow. Superoxide dismutase and deferoxamine also quenched these signals. Thus, .O2- derived .OH, R., and ROO. radicals are generated in postischemic myocardium. While the experimental techniques used can result in loss of intrinsic radicals and generation of extraneous radicals, with proper care and controls valid measurements of free radicals in biological tissues can be performed.
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PMID:Measurement and characterization of postischemic free radical generation in the isolated perfused heart. 255 26

There is a growing evidence for the role of oxygen free radicals (OFR) in mediating myocardial tissue injury during myocardial ischemia and particularly during reperfusion. But almost all of the evidence was indirect, using electron spin resonance (ESR) spectroscopy, we have directly measured OFR generated in ischemic and reperfused isolated rabbit hearts. 17 hearts were rapidly frozen in liquid nitrogen after their arrest by cardioplegic solution and sampled after 150 min of sustained hypothermic global ischemia or after reperfusion. The ESR spectra obtained from experiment have directly demonstrated that OFR is produced in significant amounts in the isolated rabbit hearts during early stage of reperfusion but only small amount during ischemia. The mitochondrial electron transport chain appeared to be the main source of OFR. We found that superoxide dismutase scavenged OFR generated during reperfusion efficiently, but catalase did not. We believe that superoxide anion, not hydroxyl radical, is the main OFR which is responsible for myocardial reperfusion injury. We also found that Salvia, a traditional Chinese medicine, a very efficient OFR scavenger, had the similar effect as superoxide dismutase.
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PMID:[Direct detection of oxygen free radicals produced by myocardial reperfusion using electron spin resonance spectroscopy]. 255 94

A case is described of gangrene of the foot and lower leg due to cold injury following exposure to liquid nitrogen. The severe damage to the entire microcirculation was followed by irreversible ischemia finally requiring amputation of the lower leg. Histology revealed conspicuous lesions of the small vessels within the entire soft tissues, with subsequent thrombotic occlusion and circulatory blockade. Some recommendations concerning occupational exposure to liquid nitrogen are added.
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PMID:[An unusual cause of gangrene: cold injury caused by liquid nitrogen]. 256 95

To determine the timing and location of renal cell regeneration after ischemic injury to the kidney and to assess whether exogenous epidermal growth factor (EGF) enhances this regenerative repair process to accelerate recovery of renal function, experiments were undertaken in rats undergoing 30 min of bilateral renal artery clamp ischemia followed by reperfusion for varying time intervals. Renal cell regeneration, as reflected by incorporation of radiolabeled thymidine within the kidney, began between 24 to 48 h and reached a peak at 72 h after renal ischemia. As demonstrated by histoautoradiography, renal thymidine incorporation was essentially confined to tubule cells. Morphometric analysis of histoautoradiograph sections of renal tissue demonstrated that the majority of labeled cells were found in renal cortex, but some labeled cells were also located in the inner stripe of the outer medulla, suggesting that injury to medullary thick ascending limbs also occurs in this ischemic model. Exogenous EGF administration produced increases in renal thymidine incorporation compared with non-treated animals at 24, 48, and 72 h after ischemic injury. This accelerated DNA replicative process was associated with significantly lower peak blood urea nitrogen (BUN) and serum creatinine levels, averaging 63 +/- 20 and 3.1 +/- 0.4 mg/dl in EGF-treated ischemic rats compared with 149 +/- 20 and 5.1 +/- 0.1 mg/dl, respectively, in nontreated ischemic rats, and was also associated with a return to near normal BUN and serum creatinine levels in EGF-treated animals approximately 4 d earlier than that observed in nontreated animals. This report is the first demonstration that EGF accelerates the repair process of a visceral organ after an injurious insult.
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PMID:Epidermal growth factor enhances renal tubule cell regeneration and repair and accelerates the recovery of renal function in postischemic acute renal failure. 259 59

A previous article (Part I) described the patient population and operative management of 666 patients who had surgery for nonruptured abdominal aortic aneurysms. This article details the perioperative complications and, by chi-square and logistic regression analysis, identifies the variables that are associated with each complication. In summarizing the results (below) the incidence of each complication is listed, along with the predictive risk factors in parentheses that have significance levels less than 0.05. Vascular morbidity data are as follows: intraoperative bleeding, 4.8%; postoperative bleeding requiring transfusion, 2.3% or repeat operation, 1.4% (large volume of blood transfusion and/or use of an autotransfusion device); intraoperative limb ischemia, 3.5%; graft thrombosis, 0.9% (femoropopliteal disease and/or distal anastomosis at the femoral level); distal thromboembolism, 3.3% (male sex, femoral popliteal disease, and/or intraoperative graft thrombosis); amputation, 1.2%; graft infection, 1 case. General morbidity data are as follows: cerebrovascular event, 0.6%; paraplegia, 1 case; cardiac event, 15.1% (age, previous episode of congestive heart failure, and/or electrocardiogram [ECG] evidence of a previous myocardial infarction); myocardial infarction, 5.2% (advancing age, angina, and/or prolonged aortic cross-clamp time); congestive heart failure, 8.9% (previous history of congestive heart failure, ECG evidence of ischemia, and/or chronic obstructive lung disease); arrhythmia requiring treatment, 10.5% (preoperative ventricular premature beats and/or respiratory failure requiring ventilation for more than 48 hours); new arrhythmia, 8.4% (angina and/or chronic obstructive lung disease); respiratory failure, 8.4% (chronic obstructive lung disease, large volume of blood transfused, and/or occurrence of postoperative bleeding, cerebrovascular accident, congestive heart failure, or myocardial infarction); renal damage with rise in creatinine or blood urea nitrogen, 5.4% and/or renal failure requiring dialysis, 0.6% (elevated preoperative creatinine, suprarenal aortic cross-clamping, and/or renal vein ligation); diarrhea without evidence of ischemia colitis, 7.1% and ischemic colitis, 0.6% (pelvic flow interrupted); prolonged ileus, 11.0% (aortoiliac occlusive disease, deterioration of renal function, prolonged ventilation, and/or preoperative history of angina); superficial wound infection, 1.5% and deep infection, 0.5% (femoral anastomosis and/or female sex); coagulopathy, 1.1% (large volume of blood transfused).(ABSTRACT TRUNCATED AT 400 WORDS)
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PMID:Multicenter prospective study of nonruptured abdominal aortic aneurysm. Part II. Variables predicting morbidity and mortality. 264 60

Polyclonal antibodies to a series of radiation chemically produced 2-nitroimidazole-protein adducts have been used in the indirect immunofluorescent detection of hypoxic cells in EMT6/Ed spheroids. The spheroids were incubated with the radioactive 2-nitrioimidazoles under atmospheres of air, several intermediate oxygen concentrations, and nitrogen. The fluorescence intensity of the marker across radii of spheroids labeled at various oxygen tensions, as measured by video image analysis, paralleled the autoradiographic grain density. Thus, we conclude that the immunohistochemical approach provides a quantitative measure of the distribution of 2-nitroimidazole adducts in spheroids. The advantages of speed, technical simplicity, economy, and independence from the requirement of radiolabeled precursor render the fluorescent marker of potential use in the clinical detection of cellular hypoxia and tissue ischemia.
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PMID:Quantitation of hypoxia in multicellular spheroids by video image analysis. 264 66

Renal atherosclerosis and fibromuscular dysplasia are the most common causes of curable human renovascular hypertension and renal failure. Vascular reconstruction often preserves renal function, but renal failure is rarely reversed, especially after days of anuria. We report a case of a 23-year-old woman who as a child underwent a nephrectomy for congenital hydroureter and renal hypoplasia. She later experienced fibromuscular dysplasia of the remaining renal artery, which ultimately progressed to a complete occlusion and 31 days of total anuria. The patient was revascularized, and within 2 months renal function returned with a blood urea nitrogen and creatinine of 9.0 and 1.0 mg/dl, respectively. After a follow-up of 6 months the patient's blood pressure remained 120/80 to 130/80 mm Hg without administration of hypertension medication. In this report we emphasize that under selected circumstances a kidney can survive prolonged ischemia and that delayed revascularization may reestablish renal function.
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PMID:Successful revascularization of an occluded renal artery after prolonged anuria. 272 67

Hippocampal brain slices that were 1000 mu thick were prepared from Sprague-Dawley rats and studied using in vitro glucose utilization under well-oxygenated conditions or after a 15 min anoxic insult produced with a nitrogen atmosphere. Autoradiography reveals that glucose utilization is increased in CA1 and CA3 stratum radiatum of 1000 mu slices, even with full oxygenation, compared to the same regions in 540 mu slices. Following anoxia, there is an initial addition increase in stratum oriens of CA1 and CA3 glucose utilization that is followed by a decline in glucose utilization in all slice regions within an hour of the insult. Because increased glucose utilization is apparent at the slice surfaces as well as at the interior, it is suggested that thick brain slices are a model of brain ischemia, not just hypoxia.
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PMID:Glucose utilization of ischemic hippocampal slices. 272 13


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