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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chronic hypoxemia was produced in 16 dogs by surgical transposition of the caudal vena cava to the left atrium to determine if chronic hypoxemia would alter the response of the myocardium to acute ischemia. An electromagnetic aortic flow probe, left atrial tube, and occlusive cuff on the left circumflex coronary artery were permanently implanted in 11 hypoxemic and 26 normal control dogs. The animals were studied in the conscious state after recovery from the surgery. Dogs with hypoxemia had a blood hematocrit value of 54.3 +/- 1.0% (SE), arterial PO(2) of 43.2 +/- 1.4 mm Hg, and 80.2 +/- 1.6% oxygen saturation. There was no difference from control animals in the ratio of left ventricular weight to body weight, but the right ventricular weight was significantly decreased in the hypoxemic dogs. Cardiac output from the left ventricle was twice that of the right ventricle. Aortic blood flow was 3.68 +/- 0.22 liters/min in hypoxemic animals and 2.64 +/- 0.19 liters/min in normal dogs. Myocardial blood flow measured with 15-mu diameter tracer microspheres was increased from 79 +/- 10 and 59 +/- 8 ml/100 g/min in left ventricular endocardial and epicardial halves, respectively, in normal dogs to 212 +/- 48 and 172 +/- 39 in dogs with chronic hypoxemia. There were no deaths in 10 hypoxemic dogs within 24 hours after complete circumflex coronary artery occlusion; 7 of 26 (27%) normal dogs died after circumflex coronary artery occlusion during the conscious state. Gross infarct size was extremely variable in both groups. Median infarct size was smaller in dogs with hypoxemia and was directly correlated with arterial PO(2) in hypoxemic dogs. There was a mild, but statistically not significant, increase in the anastomotic index of hypoxemic dogs compared with that of normal animals, suggesting that a metabolic adaptive change rather than increased collateral circulation may have been responsible for the decreased mortality and smaller infarct size in hypoxemic dogs.
Am J Pathol 1977 Dec
PMID:The effect of chronic hypoxemia on regional myocardial blood flow in the conscious dog after acute coronary artery occlusion. 59 17

The relationship between myocardial contracture and cell calcium was studied in electrically paced, isolated perfused rabbit hearts. Isovolumic left ventricular dP/dt and end-diastolic pressure were utilized as indexes of contractility and ventricular stiffness. After 60 min of low flow (ischemia) without or with reperfusion at high flow for 10 min, calcium was measured in the mitochondrial fraction and used as an indicator of intracellular calcium. Low flow led to ventricular standstill and contracture, and reperfusion produced partial mechanical recovery with end-diastolic pressure remaining markedly elevated. Nifedipine (10(-7) M), an antagonist of myocardial calcium uptake, prevented contracture and permitted nearly complete mechanical recovery without elevation in diastolic pressure. Increases in mitochondrial calcium paralleled the severity of contracture and the lack of diastolic relaxation after reperfusion. Mitochondrial calcium did not increase in hearts protected by nifedipine. Results demonstrate a close relationship between mechanical changes induced by ischemia and accumulation of intracellular calcium.
Am J Physiol 1977 Dec
PMID:Myocardial contracture and accumulation of mitochondrial calcium in ischemic rabbit heart. 59 65

The validity of a new noninvasive device, the cardiokymograph, was assessed as to its ability to detect regional myocardial wall motion by direct comparison of the analog tracing with that of an epicardial length gauge in 11 open-chest dogs. The correlation of the two methods was excellent both during control conditions and following changes induced by acute coronary occlusion. The average difference between the methods in timing of various cardiac events was only 6.2 +/- 1.9 ms at rest and 6.8 +/- 1.5 ms following ischemia (P = NS). Relative amplitude ratio correlations, determined for the four portions of the cardiac cyele (isovolumic systole, ejection, isovolumic relaxation, and diastole), were also excellent. The average correlation of the kymograph to the length gauge was r = 0.896 +/- 0.018 at rest (K = 0.977 LG + 0.033) and r = 0.932 +/- 0.013 following occlusion (K = 1.071 LG + 0.101). Thus, the cardiokymograph is a sensitive and accurate noninvasive method for detection of regional ischemic dysfunction and produces an analog tracing essentially identical to that of the epicardial length gauge.
Am J Physiol 1977 Dec
PMID:Noninvasive analysis of regional myocardial wall motion: cardiokymography. 59 68

During the forty-month period ending July, 1976, intraaortic balloon counterpulsation was used as an adjunct to medical or surgical therapy in 273 patients. Thirty-seven developed complications. Limb ischemia occurred in 16; it resolved in 12, resulted in gangrene of the toes in 1 and leg gangrene in 2, and was the casue of death in 1 patient. Aortic dissection was confirmed in 7 patients and strongly suspected in another 4. Eight of the 11 patients with dissection underwent cardiac procedures with heparinization at two days to three months after balloon insertion with no untoward effects. Septicemia developed in 2 patients, 1 of whom died of cardiogenic shock. Localized groin sepsis occurred in 8 patients, 2 of whom required removal of infected Dacron graft material. Awareness of the complications of balloon insertion, proper attention to details of balloon management at the time of insertion and removal, and continuous monitoring through a central-lumen balloon should decrease the incidence of complications.
Ann Thorac Surg 1977 Dec
PMID:Results and complications of intraaortic balloon counterpulsation. 59 68

The effect of KoQ4 on the energetics, contractility, and electrogram of the ischemized myocardium was studied in acute experiments on dogs with induced myocardial ischemia. Intracornoary administration of KoQ4, 1.3 mg/kg, directly into the focus of ischemia for 15 min promoted a decrease in the lactate level in blood draining from the ischemic zone as compared to the control data in the absence of a difference in the dynamics of the pyruvic acid content. In distinction to the control experimental series, there was no decrease in the concentration of glucose in samples of venous blood draining from the focus of ischemia. Under the effect of KoQ4 the amplitude of left ventricular pressure and the maximum rate of its growth (dp/dt) increased moderately and the ST segment and ST/R coefficient of the epicardial electrogram from the border zone of ischemia decreased. It was shown in the rat experiments that preliminary intravenous administration of KoQ4 (14 mg/kg) increased myocardial resistance to oxygen deficiency under conditions of diacetylcholine-induced apnoe.
Kardiologiia 1977 Dec
PMID:[Effect of hexahydroubiquinone-4 (KoQ4) on the bioenergetics and functional activity of the myocardium in ischemia]. 59 31

A double lumen Swan Ganz balloon catheter is introduced percutaneously into the renal artery. Temporary and repeated occlusion of the artery by inflation of the balloon are combined with hypothermic perfusion of the kidney. Thus extensive nephrolithotomies can be done without time limit as in warm ischemia. The operation field is blood-less and the parenchym is protected by perfusion. There is no need for pedicle dissection or external cooling. One complication is seen when the catheter is slipping out of the artery in cases of short renal arteries and the patient is in an extremely bent operation position for intercostal approach. Ballon occlusion without perfusion is helpful in tumor nephrectomy. Preoperative embolization is not necessary when this technique is used. Embolization means an additional procedure with further complications.
Radiologe 1977 Dec
PMID:[Balloon occlusion of the renal artery in operative urology (author's transl)]. 60 Dec 37

It has been shown that localized myocardial ischemia is accompanied by microvascular changes which produce capillary obstruction when blood flow is restored. This so-called no-reflow phenomenon has been noted in the brain, kidney, dermis and, more recently, in the myocardium. Ultrastructural studies have pointed out the role of myocardial and endothelial cells swelling. It seems likely that such damage of the vascular bed may constitute the first irreversible change during ischemia and result in failure to obtain successful reperfusion of involved myocardium. It can be suggested on the basis of recent clinical and experimental observations, that this phenomenon may play a role in subendocardial necrosis associated with cardiac surgery, and in myocytolytic necrosis. In both of these conditions, the most salient features are the microcirculatory defect and the reperfusion injury following transient ischemia. Further investigations are needed to determine the basic alterations induced by no-reflow phenomenon and the value of various prophylactic and therapeutic measures.
Biomedicine 1977 Dec
PMID:No-reflow phenomenon and acute myocardial ischemia. The need for further investigation. 60 1

Twenty-seven patients undergoing open-heart surgery were divided into three groups, i.e., control, intermittent aortic crossclamping and coronary perfusion groups. Myocardial oxygen extraction, lactate extraction, arterial-coronary sinus hydrogen ion difference, potassium difference and glucose difference were determined during the operation, as well as, postoperative stroke and cardiac indices and comparisons were made. When the ascending aorta was not crossclamped, myocardial metabolism was well preserved during and after the perfusion at a flow rate of 2.0 L./min/m2. Intermittent aortic crossclamping for 15 minutes alternating with a period of perfusion for five minutes at 30 degrees C was sufficient to protect the myocardium from ischemia. Perfusion of the left coronary artery alone at a flow rate of six per cent of total body perfusion (150 to 200 ml per minute) at 30 degrees C was sufficient to protect the myocardium when the aorta was opened. Since intermittent perfusion of the left coronary artery may produce myocardial derangement, coronary perfusion should be continuous. Otherwise topical cardiac cooling or other means of myocardial protection should be used.
Jpn J Surg 1977 Dec
PMID:Myocardial protection during open-heart surgery: intermittent aortic crossclamping versus coronary perfusion. 60 90

The experience with the treatment of 312 acute blood vessels trauma consecutive cases is generalized in this article. The problems dealing with differential estimation of reconstructive surgery, indications for reconstructive operations on patients with traumatic shock, blood loss and severe ischemia of the injured extremity are considered. Experimental studies on 35 dogs and clinical observations over 95 (30.4%) cases of traumatic shock and blood vessels injury permitted to reveal some peculiarities of homeostasis alterations when the ischemized extremity gets involved into the blood flow, and to show the grounds for using the differential tactics under such conditions.
Vestn Khir Im I I Grek 1977 Dec
PMID:[Unsolved problems of acute injury of major blood vessels of the extremities]. 60 44

Male Wistar rats were used to investigate the effects of stromafree hemoglobin (200 mg Hb/100 g body weights, i.v. as a 16.4% solution) on kidney function and morphology. Ischemia of the kidney was induced by bilateral clamping of the renal pedicle. The most severe disturbances of kidney function occurred in kidneys damaged by ischemia during the peak of Hb excretion; endogenous creatinine clearance decreased to 5% of control values, serum creatinine concentration rose 6 times as high as control values, and Hb excretion in the urine was reduced. Kidney damage after Hb loading and ischemia was more severe than damage caused by ischemia alone. These results demonstrate that the vulnerability of kidneys to damage by ischemia is increased by Hb loading.
Beitr Pathol 1977 Dec
PMID:Effect of hemoglobin loads on the function and morphology of ischemic kidneys in the rat. 61 Jul 8


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