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 splanchnic organs, and especially the pancreas and the small intestine, are susceptible to injury during ischemia and shock and the following reperfusion. This particular tissue injury is associated with a release of cardiotoxic and other toxic mediators which further aggravate the shock condition, leading to further tissue injury etc. Thereby a vicious circle is created, which is likely to contribute to collapse and death.
 ...
PMID:The splanchnic organs as the source of toxic mediators in shock. 328 18

Perioperative coronary spasm after coronary bypass surgery is increasingly recognized as a possible cause of circulatory collapse. Most of the reported cases involved the right coronary artery (RCA). A case where transient right coronary spasm provoked right ventricular ischemia and collapse is described.
 ...
PMID:Perioperative coronary spasm and right ventricular ischemia. 348 66

The renal allograft is host to a number of injuries and all its structural components are prone to damage. The glomeruli respond to these varied stimuli in many ways. The fibrinoid necrosis, thrombosis, and polymorphonuclear cell exudation that accompany hyperacute or accelerated rejection are well-recognized. The transplant may also be afflicted by forms of de novo or recurrent glomerulonephritis. Apart from these, there are other patterns of reaction. The mesangium is often the site of a rapidly reversible change; it expands readily. Arterial changes initiate ischemia and collapse of glomerular capillary spaces. Glomerulitis accompanies cases of acute rejection, but when seen as a predominant feature, usually antedates chronic rejection. Heavy proteinuria may be associated with profound alterations in the peripheral capillary basal lamina including irregular thickening, interposition of mesangial cell cytoplasm, and lamellation. Allografts with these glomerular changes eventually fail.
 ...
PMID:Glomerular changes in renal allografts. 351 May 33

The hemodynamic effects of portal triad clamping (PTC) were studied in 48 adult patients scheduled for elective liver resection. Prior to hepatic resection the effects of a short period of PTC (3-5 min) were evaluated in all 48 patients: mean arterial pressure increased 21%, whereas pulmonary capillary wedge pressure and cardiac index decreased 10 and 17%, respectively. Systemic vascular resistance increased 48%. In 34 patients a liver resection was performed during PTC and hemodynamic measurements were repeated throughout the duration of liver ischemia, which ranged from 14 to 68 min. Hemodynamic changes occurred in the first 3 min and persisted thereafter. After releasing the clamp, hemodynamic parameters returned to initial values in 3 min. These results confirm that PTC does not induce the cardiovascular collapse in humans that it does in common laboratory animals and demonstrate that humans tolerate PTC for periods up to 1 hr.
 ...
PMID:Hemodynamic effects of portal triad clamping in humans. 361 92

Changes in diastolic chamber distensibility (DCD) during hypoxemia and ischemia were studied in isolated-buffer-perfused rabbit hearts. Two minutes of hypoxemia (low PO2 coronary flow) resulted in a shift of the diastolic pressure-volume curve to the left, i.e., distensibility was decreased (hypoxemic contracture). In contrast, 2 minutes of ischemia (zero coronary flow) resulted in an initial shift of the diastolic pressure-volume curve to the right indicating increased distensibility, which was followed by a later (30 minutes) shift to the left (ischemic contracture). Two minutes of ischemia superimposed on hypoxemia caused complete reversal of contracture. A quick stretch and release applied to the myocardium reversed late ischemic contracture but did not effect early hypoxemic contracture. The role of intracellular pH in modulating changes in DCD during hypoxia and ischemia was studied using phosphorus-31 nuclear magnetic resonance spectroscopy of isolated-buffer-perfused rat hearts that demonstrated changes in DCD similar to rabbit hearts during hypoxemia and ischemia. Intracellular pH decreased from 7.03 +/- 0.02 to 6.87 +/- 0.03 (p less than .01) during 2 minutes of ischemia but did not change significantly during 4 minutes of hypoxemia. When 2 minutes of ischemia were superimposed on hypoxemia, pH decreased from 6.99 +/- 0.01 during hypoxemia to 6.88 +/- 0.02 after 2 minutes of ischemia (p less than .01), concomitant with the complete reversal of hypoxemic contracture. These results suggest different mechanisms for late ischemic and early hypoxemic contracture and also suggest an explanation for the opposite initial changes in DCD seen after brief periods of ischemia and hypoxemia. The early development of contracture during hypoxemia and rapid redevelopment of diastolic tension after quick stretching are consistent with the hypothesis that hypoxemic contracture results from persistent Ca++-activated diastolic tension secondary to impaired calcium resequestration by the sarcoplasmic reticulum. In contrast, the late development of contracture during global ischemia and reversal by quick stretching is compatible with rigor bond formation. The initial increase in distensibility during early ischemia and the reversal of hypoxemic contracture by a brief period of superimposed ischemia probably is the result of two factors present during ischemia but not during hypoxemia: the collapse of the coronary vasculature and loss of the "erectile" effect and, the rapid development of intracellular acidosis, which has been shown to affect myofibrillar calcium sensitivity, and this may lead to a decrease in Ca++ activated diastolic tension.
 ...
PMID:Acute alterations in diastolic left ventricular chamber distensibility: mechanistic differences between hypoxemia and ischemia in isolated perfused rabbit and rat hearts. 380 27

The authors retrospectively studied victims of sudden cardiac death who experienced cardiac arrest before and after arrival of emergency personnel in order to define possible etiologic factors. There were 265 patients in the arrest-after-arrival (AAA) group and 414 patients in the arrest-before-arrival (ABA) group. All patients in the AAA group had symptoms prior to cardiac arrest. Approximately half the patients in the ABA group had symptoms. The presence or absence of symptoms prior to cardiac arrest appeared strongly associated with the cardiac rhythm at time of collapse and with discharge. Of patients with symptoms, 61% were in ventricular fibrillation or ventricular tachycardia, as compared with 93% of patients without symptoms (P less than 0.001); 32% of patients with symptoms were discharged, as compared with 57% of patients without symptoms (P less than 0.001). These data suggest two potential etiologies for sudden cardiac arrest; thrombosis/ischemia (associated with symptoms) and electrical (associated with no symptoms). Inasmuch as the AAA group represented 14% of witnessed cardiac arrests, patients with symptoms of myocardial ischemia or infarction should be aggressively treated.
 ...
PMID:Out-of-hospital cardiac arrest: significance of symptoms in patients collapsing before and after arrival of paramedics. 394 38

Lightning streaks of Moore are recurrent stereotypic vertical visual phenomena that must be distinguished from similar symptoms due to retinal ischemia, optic disk abnormalities, or mechanical retinal or optic nerve stimulation. These brief flashes are oriented vertically and are perceived in the temporal visual field after eye movement. Senescent posterior vitreous changes induce collapse and detachment with persistent vitreoretinal adhesions through which mechanical forces exert traction on the macula and retina, inducing photopsias. Clinical recognition of these symptoms avoids unnecessary diagnostic interventions.
 ...
PMID:Lightning streaks of Moore: a cause of recurrent stereotypic visual disturbance. 401 Sep 52

It has been suggested that histamine contributes to lethal circulatory collapse after acute superior mesenteric artery occlusion. The activity of the histamine inactivating enzyme diamine oxidase, the release of the amine, and the effect of histamine receptor antagonists was therefore studied in rabbits. The main results were: (a) Diamine oxidase activity decreased by 60% after intestinal ischemia and reperfusion. A monoexponential dose-response relationship was found between the specific diamine oxidase inhibitor aminoguanidine and reduced survival time. (b) Plasma histamine levels in the right atrium rose only slightly after ischemia, but considerably during reperfusion of the gut, and remained high for at least 20 min. In sham-operated animals the plasma histamine concentration was unchanged throughout the experiment. The histamine content in the intestinal wall did not fall significantly at any time after mesenteric artery occlusion and reperfusion. (c) The aminoguanidine-induced reduction in survival time was completely reversed by pre-treatment of the animals with the H1-receptor antagonist dimethylpyridine and the H2-receptor antagonist cimetidine. This study provides strong evidence for the protective role of intestinal diamine oxidase in intestinal ischemia.
 ...
PMID:Intestinal diamine oxidase and histamine release in rabbit mesenteric ischemia. 616 12

The findings of elevated BMP in the preradiologic stages of INFH and the histologic findings of extensive bone marrow ischemia and necrosis preceding trabecular death support the pathogenetic concept that INFH represents a compartment syndrome similar to the anterior tibial compartment syndrome following tibial fracture and increased intracranial pressure following closed head injury. The documentation by multiple authors that decompression instituted in the preradiologic stage leads to a high percentage of success both in relief of symptoms and lack of radiographic progression further supports this hypothesis. The compartment syndrome can be viewed as the final common path down which multiple etiologic entities proceed to a clinical syndrome that has a remarkably uniform clinical and radiographic expression. Acceptance of this pathogenetic concept leads to an aggressive approach to early diagnosis and treatment. Even in these circumstances, the majority of patients with INFH will seek help for the first side only after collapse has begun, at which time a decompression offers only a temporary relief of symptoms but does not appear to significantly alter the course of the disease over the long term. However, since the majority of patients with nontraumatic INFH will develop the disease on the second side and since only a small percentage have bilaterally collapsed femoral heads, an opportunity frequently exists to salvage the second side.
 ...
PMID:Pathogenesis of ischemic necrosis of the femoral head. 654 72

The indications for operation to correct acute mechanical defects after myocardial infarction are clearly established. Less clear is the use of surgical procedures for nonmechanical complications such as persistent ischemia or circulatory collapse. Between 1974 and 1981, 80 patients underwent coronary artery bypass grafting (CABG) within 2 weeks of infarction. Continued pain was the indication in 83% and cardiogenic shock in 17%. Seventeen patients were operated upon within 24 hours of infarction, 35 from 1 to 7 days, and 28 from 8 to 14 days. Eighty-one percent were men; mean age was 58 years. In 39% of patients the infarction was the premier symptom of coronary artery disease. Sixty-two percent had impaired left ventricular function as judged by left ventricular end-diastolic pressure greater than 15 mm Hg or abnormal wall motion seen on ventriculogram. Overall operative mortality was 5.0%; early mortality by indication was 3.0% for pain and 14.3% for shock. Operation for pain carried a 7.7% mortality if done within 48 hours of infarction and was 0% for those patients operated upon after that time. The status of 90% of all patients was known as of December, 1981, with a mean follow-up of 2.9 years. Life-table analysis demonstrates a 5 year survival rate of 85% +/- 6% in the group operated upon for pain. CABG in the immediate postinfarction period can be done safely with a 5 year survival in patients without hemodynamic compromise comparable to that of patients with chronic angina undergoing elective operation. These results should encourage the application of early postinfarction CABG in other high-risk subgroups of patients.
 ...
PMID:Coronary bypass operation following acute complicated myocardial infarction. 660 Dec 8


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