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)

A variety of infectious processes produce cutaneous and soft-tissue involvement of the lower extremities. Patients with conditions leading to ischemia and devitalized tissues, and those with diabetes mellitus are predisposed to developing these infections. The signs and symptoms and bacteriology of many of these infections may overlap, leading to confusion in diagnosis and subsequent management. Very often the progression of some of these infections is rapid and life-threatening, although mutilating-type infections are not uncommon. Optimal management requires a multidisciplinary approach, with the surgeon, microbiologist, pathologist, internist, and infectious disease specialist working in close cooperation with each other.
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PMID:Infections involving the skin and soft tissues of the lower extremities. 355 52

Optimal infrainguinal revascularization should provide limb salvage for the longest duration of time. It is not known whether limb salvage is longer with an initial below-knee popliteal or tibial in situ saphenous vein graft or with staged bypasses; that is, an initial above-knee popliteal prosthetic bypass if feasible, followed by a more distal vein graft should the above-knee prosthetic graft fail. A retrospective review of 197 lower extremity vascular reconstructions performed since 1976 utilizing polytetrafluoroethylene (PTFE), umbilical vein, or in situ saphenous vein was completed. The data were analyzed for differences in limb salvage and prevention of limb threatening ischemia among three subgroups: above-knee prosthetic bypass, below-knee or tibial in situ saphenous vein bypass, and staged reconstructions (above-knee prosthetic bypass with subsequent in situ bypass). The groups were similar with respect to severity of limb threatening ischemia as indicated by mean preoperative ankle-brachial indices. Cumulative secondary limb salvage at 36 months was 73 percent for prosthetic grafts in the above-knee position, 78 percent for in situ saphenous vein grafts in the below-knee or tibial position, and 87 percent for staged reconstruction with an initial prosthetic graft to the above-knee position followed by a distal in situ vein bypass when the prosthetic graft fails.
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PMID:Staged infrainguinal revascularization: initial prosthetic above-knee bypass followed by a distal vein bypass for recurrent ischemia. A valid concept for extending limb salvage? 374 Mar 61

Antithrombotic therapy in prevention and management of stroke is evolving rapidly as new clinical data better define indications. Stroke is a syndrome with several pathophysiologic bases, not one clinical entity. Optimal use of medical and surgical therapy requires definition of the specific mechanism of brain ischemia in the individual patient.
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PMID:Antithrombotic therapy for cerebrovascular disease. Prevention and treatment of stroke. 378 78

The isolated perfused organ is more sensitive to the toxicity of oxygen since hypothermia reduces the activities of enzymes responsible for minimizing oxygen toxicity. To protect the organ under these conditions reducing agents must be added to the perfusate. Quantitation of the resulting reduction is best obtained by measurement of the oxidation-reduction potential of the perfusate. A device was designed for this purpose and, by electrochemical principle, controlled reduction of the oxidized form of the oxidation-reduction couple was affected. Kidneys were perfused with cryoprecipitated plasma. With the electrochemical cell in the circuit, the oxidation-reduction potential of the perfusate was adjusted by the addition of ascorbic acid and glutathione and the cell was driven by a battery-powered potentiostat. Kidneys subjected to 60 minutes of warm ischemia had optimal survival at -20 mV. Preservation for six days in a monitored group had no survivors, whereas kidneys with oxidation-reduction support maintained life. Optimal oxidation-reduction support maintained life. Optimal oxidation-reduction was at or near -17 mV. These data show a requirement of an optimal oxidation-reduction potential to reverse warm ischemia damage and to prolong the period of ex vivo preservation of isolated perfused organ.
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PMID:Oxidation-reduction maintenance in organ preservation. 398 89

Intraarterial thrombolysis by remote intravenous or direct intraarterial infusion of streptokinase is possible. The latter may be more effective with a lesser potential for systemic hemorrhagic complications because of the smaller dose administered directly in the area. Fifty patients with prosthetic graft, embolic, and renal artery occlusions were evaluated. Embolic occlusion responded dramatically, particularly since lytic therapy was initiated at an early stage. Patients with severe ischemia or those with simple localized occlusion were best treated by surgical means. Successful thrombolysis was also obtained with renal artery occlusions combined with percutaneous transluminal angioplasty. The management of patients with prosthetic graft occlusion by lytic therapy is complex. Optimal results can be obtained in patients presenting with occluded grafts after the immediate postoperative period and in those in whom previous satisfactory runoff has been demonstrated. Failure of lysis in this group is associated with a high incidence of limb loss due to unreconstructable obliterative disease. Successful lysis of occluded prosthetic grafts will often require corrective angioplasty or surgical revision.
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PMID:Improved patient selection for enzymatic lysis of peripheral arterial and graft occlusions. 623 54

The ability of dl-verapamil to enhance myocardial protection when given before, during, or after myocardial ischemia was assessed with the use of an isolated working rat heart model of cardiopulmonary bypass and ischemic cardiac arrest. Under conditions of normothermic ischemic arrest (30 minutes at 37 degrees C), the addition of verapamil enhanced the protective properties of the St. Thomas' Hospital cardioplegic solution. Optimal protection was observed with verapamil concentrations of 0.5 mg/L (1.09 mumol/L) of cardioplegic solution. Under these conditions, postischemic enzyme leakage was reduced by 32.2% and the postischemic recovery of aortic flow was improved by 18.7%. Despite the additional protection at normothermia, the drug at several concentrations appeared unable to improve functional recovery after an extended period of hypothermic arrest (150 minutes at 20 degrees C), although under these conditions its inclusion in the cardioplegic solution could substantially reduce enzyme leakage. In other studies, the ability of various doses of verapamil alone as a substitute for the cardioplegic solution was examined. At the optimal dose (again 0.5 mg/L), and under normothermic conditions, verapamil alone was a good protection against ischemic injury, although this protection did not match that afforded by the St. Thomas' Hospital cardioplegic solution. In similar studies under hypothermic conditions, the drug failed to afford tissue protection, perhaps indicating some common modality between hypothermia and verapamil-induced protection. Pretreatment with verapamil (0.1 mg/L) prior to ischemia offered moderate additional protection, but its use during reperfusion failed to enhance overall recovery.
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PMID:Cardioplegia and slow calcium-channel blockers. Studies with verapamil. 687 61

A reproducible noninvasive monkey model for global brain ischemia with exact insult (no flow x 16 min) to the brain, with survival and with standardized preischemic, ischemic and postischemic variables is described. This model allowed us to demonstrate for the first time: 1) that a substantial part of brain damage early postischemia is reversible and amenable especially to barbiturate treatment; 2) that the postischemic brain shows increased vulnerability for additional insults. Optimal postischemic intensive monitoring and immobilization for 24-48 hours is important for improved outcome; 3) that immediate postischemic reperfusion pressure (MAP 110-150 mm Hg) significantly improves the outcome; 4) that heparinisation during ischemia has no protective effect and 5) that postischemic heparinisation and intravenous hemodilution does not ameliorate the outcome. The protective effect of trimetaphan against neurogenic pulmonary edema can be explained by the prevention of pulmonary hypertension but its protective effect on the development of secondary cerebral edema has to be elucidated.
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PMID:[Pathogenesis and treatment of anoxic encephalopathy. Definition and importance of experimental animal models (author's transl)]. 746 71

In laryngoplasty procedures, laryngotracheal soft tissue defects are often repaired using skin grafts. While stenting is necessary to approximate and immobilize the graft, prolonged stenting causes increased bacterial counts, granulation tissue formation, tissue ischemia, and graft failure. Optimal time for stent removal has not been experimentally defined. Using the ferret animal model, 24 laryngoplasty procedures were performed. The subjects were stented by group for 0, 3, 7, 14, or 28 days. Analysis consisted of quantitative bacteriology, dye perfusion, and quantitative histologic assessment of graft viability. Tissue culture results revealed that by 3 days after the procedure all groups had 10(5) CFU of bacteria per gram of tissue. Graft viability in successful procedures was maximal in the 7-day group and statistically significant from the 3-day to the 28-day groups. In conclusion, while stenting is necessary for graft adherence, prolonged exposure to local tissue sepsis leads to progressive graft destruction.
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PMID:The fate of the skin graft in laryngoplasty. 766 31

Active oxygen species including hydrogen peroxide (H2O2) play a major role in ischemia-reperfusion injury. In the present study, changes in myocardial H2O2 content as well as its subcellular distribution were examined in rat hearts subjected to ischemia-reperfusion. Isolated perfused rat hearts were made globally ischemic for 20 or 30 minutes and were reperfused for different durations. H2O2 content in these hearts was studied biochemically and changes were correlated with the recovery of function. These hearts were also analyzed for subcellular distribution of H2O2. Optimal conditions of tissue processing as well as incubation medium were established for reacting cerium chloride with H2O2 to form cerium perhydroxide, an insoluble electron-dense product. The chemical composition of these deposits was confirmed by x-ray micro-analysis. Global ischemia caused complete contractile failure in minutes and after 30 minutes of ischemia, these was a > 250% increase in the myocardial H2O2 content. Depressed contractile function recovery in the early phase of reperfusion was accompanied by approximately a 600% increase in the myocardial H2O2 content. Brief pre-fixation with low concentrations of glutaraldehyde, inhibition of alkaline phosphatase, glutathione peroxidase, and catalase, post-fixation but no post-osmication, and no counterstaining yielded the best cytochemical definition of H2O2. In normal hearts, extremely small amounts of cerium hydroperoxide precipitates were located on the endothelial cells. X-ray microanalysis confirmed the presence of cerium in the reaction product. Ischemia resulted in a stronger reaction, particularly on the sarcolemma as well as abluminal side of the endothelial cells; and upon reperfusion, cerium precipitate reaction at these sites was more intense. In the reperfused hearts, the reaction product also appeared within mitochondria between the cristae as well as on the myofibrils, but Z-lines were devoid of any precipitate. The data support a significant increase in myocardial H2O2 during both the phase of ischemia and the first few minutes of reperfusion. A stronger reaction on the sarcolemma and abluminal side of endothelial cells may also indicate enhanced H2O2 accumulation as well as vulnerability of these sites to oxidative stress injury.
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PMID:Hydrogen peroxide changes in ischemic and reperfused heart. Cytochemistry and biochemical and X-ray microanalysis. 767 88

Optimal techniques of heart-lung preservation are yet to be defined. The aim of this study was to develop, in a canine model, a method of heart-lung preservation which would permit distant procurement of the organs. The animals were divided into 2 groups. In the experimental group (N = 6) the method of preservation consisted of cold cardioplegic arrest of the heart with St. Thomas' Hospital solution containing superoxide dismutase, catalase and deferoxamine, followed by cold pulmonary artery flush with modified Euro-Collins solution to which prostaglandin E1, superoxide dismutase, catalase, deferoxamine and Dextran 40 were added. Following harvesting, the heart-lung block was stored for 8 hours in cold (4 degrees C) Euro-Collins solution containing superoxide dismutase, catalase, deferoxamine, lactobionic acid, raffinose, mannitol, Dextran 40, magnesium sulfate, insulin and penicillin. In the control group (n = 6), the heart-lung block underwent the same treatment as the experimental group except that lactobionic acid, raffinose and insulin were omitted from the storage solution, and that oxygen radical scavengers were excluded from the cardioplegic, pneumoplegic and storage solutions. Histologic and electron microscopic examinations of heart-lung specimens taken before and after 8 hours cold storage of the organs suggested that our preservation technique may be effective in preventing ischemia-induced injury.
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PMID:Heart-lung protection from ischemic injury during 8 hour hypothermic preservation. 771 31


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