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)

We studied whether electrophysiological response to ischemia could be different in hypertrophied left ventricle of spontaneously hypertensive rats (SHRs) and in normal left ventricle of normotensive Wistar-Kyoto (WKY) rats. For that purpose, we used a two-compartment tissue bath in which one-half of a left ventricular strip was exposed to normal conditions and the other part to ischemic conditions (low pH, hypoxia, and hyperkalemia). Electrical activity was recorded using standard microelectrodes in normal and hypertrophied preparations. Under basal conditions, the action potential duration (APD) and effective refractory period (ERP) were longer in SHRs than in WKY rats (118 +/- 9 ms vs 81 +/- 3 ms, p less than 0.05 and 90 +/- 9 ms vs. 74 +/- 4 ms, p less than 0.05, respectively). During ischemia, the APD and ERP changed in opposite ways in both groups and we observed the development of postrepolarization refractoriness that was greater in hypertrophied than in normal hearts. Maximum upstroke velocity (Vmax) values were 229 +/- 12 and 227 +/- 10 V/s in the SHR and the WKY preparations, respectively. Three minutes after the induction of ischemia, Vmax values decreased to 46 +/- 7 V/s in SHRs and to 106 +/- 12 V/s in WKY rats. A significant increase in subendocardial collagen density was measured in SHR left ventricle compared to WKY rats (4.39 +/- 0.34% vs. 1.66 +/- 0.15%, p less than 0.05), which might partly explain the impaired conduction observed in hypertrophied preparations during ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Electrophysiological responses of hypertrophied rat myocardium to combined hypoxia, hyperkalemia, and acidosis. 171 65

Amputated human fingers were used to observe the morphologic changes in degeneration of Pacinian corpuscles, and postoperative moving two-point discrimination of the replanted fingers was examined to analyze sensory recovery after replantation. Normal corpuscles are composed of an axon terminal and inner and outer cores, resembling a sliced onion. The inner core is composed of thin, multilayered lamellar cells, and the outer core consists of multiple layers of thin perineurial cells. Based on our morphologic findings, following mitochondrial degeneration in the axon terminal, the terminal and inner core cells disappeared within 9 to 16 hours, but the outer core did not lose its structure until more than 24 hours after amputation. Collagen fibrils in the corpuscles appeared from 5 hours after amputation and periodically increased their amount up to 27 hours after amputation. Postoperative sensory recovery of the replanted fingers was significantly poorer with 9 hours or more of cold ischemia. These findings suggest that the inner core cells originating from Schwann cells degenerate at over 9 hours after amputation, and this may be related to the poor sensory recovery of replanted fingers. It also appears that the outer core cells originating from the perineurial cells in the amputated fingers survive even up to 27 hours after amputation and produce collagen fibrils in the extramatrix spaces of the outer core cells.
 ...
PMID:Electron microscopic observations of degeneration of human Pacinian corpuscles in amputated fingers. 173 91

The successful resection of an abdominal aortic aneurysm is presented in a patient who had undergone kidney transplantation 4 years previously. Because the transplanted kidney is more sensitive to ischemia than a normal one, a femoro-femoral bypass with a pump oxygenator was used for perfusion of the transplanted kidney during crossclamping. During the clamping time of 40 minutes kidney perfusion was maintained with a perfusion pressure of 60 to 80 mmHg and the flow was 600 to 1000 ml/min. A collagen-seeded Dacron graft (diameter: 18 mm, length: 12 mm) was interposed. The postoperative course was uncomplicated. We believe that performing the femoro-femoral bypass with a pump oxygenator is an effective and simple method for kidney protection in such operations.
 ...
PMID:Abdominal aortic aneurysm repair after renal transplantation with extracorporeal bypass. 178 46

The effect of KW-3635 (sodium (E)-11-[2-(5,6-dimethyl-1-benzimidazolyl) ethylidene]-6,11-dihydrodibenz[b,e] oxepine-2-carboxylate monohydrate, CAS 127166-41-0), a novel thromboxane A2 (TxA2) receptor antagonist, on collagen-induced coronary ischemia was studied in guinea-pigs. Under pentobarbital anaesthesia, intravenous injection (i.v.) of collagen (1 mg/kg) induced abnormal ECG changes such as ST-T changes, elevation of T-wave arrhythmia and cardiac arrest in severe cases. The changes of ECG (leads I, II and III) were recorded for 10 min following collagen injection. KW-3635 (25-50 mg/kg p.o.) remarkably improved the collagen-induced ischemic ECG changes. The effect of KW-3635 was more potent than those of daltroban, isbogrel and ticlopidine. Neither nifedipine nor propranolol had any effect. The plasma thromboxane B2 level in the KW-3635-treated animals was lower in comparison with those in both the control and daltroban-treated animals. These results suggest that TxA2 may play a role in this model of coronary ischemia and that KW-3635 is effective in the treatment of ischemic heart disease.
 ...
PMID:Beneficial effect of the novel thromboxane A2 receptor antagonist sodium (E)-11-[2-(5,6-dimethyl-1-benzimidazolyl)ethylidene]-6,11- dihydrodibenz[b,e]oxepine-2-carboxylate monohydrate on collagen-induced coronary ischemia in guinea-pigs. 181 24

In essential hypertension, ventricular function is determined primarily by the degree of hypertrophy (myocardial factor) and by organic complications in the coronary artery (coronary factor). Ventricular function is inversely correlated with ventricular size and systolic wall stress, inasmuch as ventricular function diminishes when these two variables increase. Even the young hypertensive heart of normal size with no angiographic abnormalities appears to be prone to ischemia, because the coronary reserve is seriously limited even in the absence of coronary stenosis. Unlike ventricular distensibility, myocardial compliance may be normal, even in the presence of pronounced myocardial hypertrophy. As myocardial compliance decreases, systolic wall stress increases and ventricular function is reduced. The hypertensive heart, the most common form of an irregular hypertrophy of the ventricular wall, is found in 14% of such cases. Analysis of the degree of hypertrophy shows that the hypertrophy can be inappropriately high (high mass-to-volume ratio, reduced wall stress), appropriate, or inappropriately low (normal mass-to-volume ratio, increased wall stress). One of the profound mechanisms influencing both myocardial and coronary function in hypertensive heart disease is the pressure-dependent development of smooth vascular hypertrophy (media) or coronary resistance vessels. Consequently, the oxygen supply to the myocardium is impaired and secondary lesions occur such as fibrosis, increased myocardial and perivascular collagen content and scars within the heart muscle. Diastolic dysfunction develops, as well as an increase in myocardial stiffness, thus promoting the transition from the concentric (compensated) to the eccentric or dilated (decompensated) state, with the consequence of the occurrence of cardiac failure. On the basis of both functional and morphological criteria, evidence is presented in this report that coronary small vessel disease is one of the underlying mechanism for the development of cardiac failure in hypertensive heart disease.
 ...
PMID:Development of cardiac failure by coronary small vessel disease in hypertensive heart disease? 183 64

Changes in left ventricular remodeling due to antihypertensive therapy have been demonstrated in experimental animal studies although no quantitative relationship has been shown between correction of blood pressure and regression of myocardial mass. As regards the qualitative aspects of regression, only the ACE inhibitors have been shown to prevent the development and induce regression of the excess collagen content of the myocardium submitted to chronic pressure overload. The problems posed by remodeling in clinical practice are more complex: should regression of myocardial mass itself be the therapeutic objective in the absence of a practical method of analysing the interstitial factor of hypertensive disease or should we concentrate on the satellite problems of hypertrophy which are correction of ischemia, left ventricular filling abnormalities and arrhythmias. For each of these clinical problems, the benefits attributed to changes in remodeling, though probable, are to a large degree hypothetical. The benefits offered by these drugs which reduce ventricular hypertrophy are, however, considerable.
 ...
PMID:[Left ventricular remodeling and hypertension. Course with antihypertensive therapy]. 183 22

We investigated incidence, severity, and distribution of coronary atherosclerosis, acute thrombosis, and plaque fissuring in ischemic heart disease (both unstable-acute syndromes and chronic ischemia) and in nonischemic controls. We also studied the structural, immunohistochemical, and biochemical profile of plaques, with and without thrombus, including morphometry, immunophenotyping of inflammatory infiltrates, cytokine presence, and ultrastructural features. Critical coronary stenosis was almost the rule in both acute and chronic ischemic series (greater than 90%) whereas it reached 50% in control subjects. Thrombosis was principally characteristic of unstable-acute ischemic syndromes (unstable angina, 32%; acute myocardial infarction, 52%; cardiac sudden death, 26%) but was also found in chronic ischemia (stable angina, 12%; ischemic cardiomyopathy, 14%) and in control subjects (4%). Plaque fissuring without thrombus occurred in low percentages in lipid-rich, severe eccentric plaques in most series. Major differences were found between pultaceous-rich versus fibrous plaques rather than between plaques with or without thrombus. Pultaceous-rich plaques were frequent in sites of critical stenosis, thrombosis, and ulceration. Inflammatory infiltrates, i.e., T cells, macrophages, and a few beta cells, mostly occurred in lipid-rich, plaques unrelated to thrombus. In adventitia, infiltrates were a common finding unrelated to any syndrome. Necrotizing cytokines such as alpha-TNF were immunohistochemically detected in macrophages, smooth muscle, and intimal cells and detected by immunoblotting in 67% of pultaceous-rich plaques, either with or without thrombus. Immune response mediators such as IL-2 were also expressed in analogous plaques but in a minor percentage (50%-40%). Media were extensively damaged in severely diseased vessels with and without thrombus. Ultrastructural study showed that the fibrous cap was either highly cellular or densely fibrillar. Intimal injury with collagen exposure was often associated with platelet adhesion, whereas foamy cell exposure was not. In conclusion, investigated parameters were essentially similar in plaques, both with and without thrombus, whereas major differences were found between pultaceous-rich and fibrous plaques. Since platelets adhere to exposed collagen and not to foam cells, the type of exposed substrates could play a major role in thrombosis.
 ...
PMID:Coronary atherosclerotic plaques with and without thrombus in ischemic heart syndromes: a morphologic, immunohistochemical, and biochemical study. 189 66

Dimethylsulfoxide (DMSO) has been in clinical use since the early 1960s. In 1967 the discovery that DMSO can greatly reduce ischemia in experimental pedicle flaps stimulated its use in plastic surgery by the authors since 1976. In 1987 its ability to soften collagen, thus permitting degrees of immediate intraoperative tissue expansion hitherto unknown, was applied clinically for the first time. Evolving use of topical 70% DMSO alone, in combination with intravenous DMSO, and intravenous DMSO alone with greater efficacy is discussed. Cases of intraoperative tissue expansion for large lesion excision and use in abdominoplasty to maximize skin resection are discussed. In breast reconstruction, maximal tissue expansion in minutes with immediate placement of large permanent prostheses ends the delay of reconstruction and problems of chronic tissue expander capsule formation and gives this technique a clear advantage over other reconstructive techniques.
 ...
PMID:Dimethylsulfoxide (DMSO) for human single-stage intraoperative tissue expansion and circulatory enhancement. 195 Aug 7

Serum levels of type III procollagen peptide (P-III-P) were measured by radioimmunoassay in clinically normal adult ponies (n = 15) and horses (n = 10). The mean serum levels of P-III-P from the ponies, 10.4 +/- 2.9 (SD) ng/mL, and the horses, 12.2 +/- 2.6 (SD) ng/mL, were not significantly different. Segments of jejunum were made ischemic to induce fibrous peritoneal adhesions in two ponies, and serum P-III-P levels were measured on days 4, 5, 7, 14, and 21. An exploratory celiotomy on day 21 revealed that the ischemic injury had induced fibrosis of the mesentery and bowel, but no adhesions had formed. The fibrotic mesentery contained type III collagen. The highest mean serum level of P-III-P, 23.0 +/- 3.5 (SD) ng/mL on day 7, was more than 4 SD above the mean from the normal ponies. There was a significant difference in the serum P-III-P levels in the ponies on days 0 (7.1 +/- 1.6 ng/mL) and 7 (23.0 +/- 3.5 ng/mL). Serum levels of P-III-P may be useful to study fibrosis associated with intestinal ischemia.
 ...
PMID:Serum levels of type III procollagen peptide in Equidae before and after intestinal ischemia. 196 14

The Caerphilly Collaborative Heart Disease Study is based on a large cohort of men (2,398) aged 49-66 years at the time of study. Platelet aggregation induced by collagen, thrombin, and ADP was measured in fasting blood samples and was related to prevalent angina, past myocardial infarction, and electrocardiographic evidence of ischemic heart disease. A number of subjects had taken aspirin, other nonsteroidal anti-inflammatory drugs, or other drugs affecting platelet aggregation 7 days before blood sample collection; after the exclusion of these subjects, data were available for 1,811 men. No relations were demonstrated with angina, but significant relations were shown between past myocardial infarctions and electrocardiographic evidence of ischemia and ADP-induced aggregation (both primary and secondary) and between electrocardiographic evidence of ischemia and thrombin-induced aggregation. The strongest relation indicated more than a twofold increase in the odds of a past myocardial infarction in subjects of the highest fifth of ADP-induced primary platelet aggregation compared with the lowest fifth. No significant relations were detected with collagen-induced aggregation. Accounting for a number of possible confounding factors had a relatively small impact on the relations between platelet aggregation and ischemic heart disease. Other evidence, including the well-established effect of aspirin on reducing the incidence of ischemic heart disease, indicates that the relations we describe are unlikely to be simply an effect of IHD on platelets.
 ...
PMID:Ischemic heart disease and platelet aggregation. The Caerphilly Collaborative Heart Disease Study. 198 96


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