Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

To determine whether perfusion preservation affected the structure and survival of kidney transplants, we correlated clinical and histologic data in 77 kidneys biopsied one hour after transplantation. Twenty-one of 36 perfusion-preserved kidneys had a glomerular capillary lesion suggestive of intravascular coagulation. None of 41 kidneys preserved by hypothermia alone had this lesion. Presence of the lesion did not correlate with donor or recipient characteristics, warm or cold ischemia time, HLA match, percentage of preformed lymphocytotoxic antibody titers or perfusion characteristics. Of 21 transplants with the lesion, nine required nephrectomy by one month, and one-month serum creatinine was less than 2.0 mg per deciliter in only three of the remaining 12 transplants. We conclude that perfusion preservation may cause pathologic changes that may adversely affect kidney-transplant function. The causes of the pathologic process remain unclear.
 ...
PMID:Perfusion nephropathy in human transplants. 79 Jan 84

Renal preservation has contributed to improvements in human cadaver kidney transplantation in terms of viability testing and logistics. Unfortunately, the antigenicity of a kidney has not been reduced by our present preservation methods; consequently, immunologic problems in cadaver kidney transplantation still remain. Simple cold storage is an acceptable method for kidneys subjected to minimal warm ischemia. It can be used where anticipated storage time will not exceed 10 to 15 hours. Pulsatile or nonpulsatile machine perfusion will give better results especially when kidneys have sustained up to 60 minutes warm ischemia. Where there is also a need for storage time longer than 15 hours, perfusion should be used. Cryoprecipitated millipore-filtered plasma remains the most commonly used perfusate. Preservation really begins before the harvesting. Present preservation techniques cannot revive a dying kidney. No single test will determine the degree of viability of a kidney. A systematic multidisciplinary effort is needed to augment our understanding and knowlege about the effect of hypothermia on organs. Hopefully these efforts will result in the development of an organ bank whereby many more kidneys will be available for transplantation.
 ...
PMID:Controversy in organ preservation. 79 Jul 30

Subendocardial ischemia develops in hearts that are fibrillated during cardiopulmonary bypass when: (1) the normal ventricle is fibrillated with a sustained electrical stimulus, (2) the hypertrophied ventricle is allowed to fibrillate spontaneously, (3) the fibrillating heart becomes distended, or (4) the perfusion pressure is reduced to approximately 50 mm Hg. Myocardial hypothermia reduces cardiac oxygen requirements during fibrillation but does not prevent ischemia when perfusion pressure falls to levels frequently attained during clinical open-heart operations. The ischemia occurs because flow cannot rise sufficiently to meet the metabolic demands of ventricular fibrillation. The forces interacting to impede adequate flow to the subendocardium during ventricular fibrillation are: (1) the compressive forces exerted on subendocardial muscle by the strength of fibrillation, (2) the compressive forces resulting from raised intracavitary pressure due to occlusion or malfunction of the ventricular vent, and (3) the evolution of myocardial edema as ischemia is prolonged. We have abandoned the use of ventricular fibrillation in clinical open-heart operations and now allow the heart to beat continually with adequate perfusion pressure. We have not needed to use inotropic drugs postoperatively after aortic or mitral valve replacement since adopting this technique.
 ...
PMID:Ventricular fibrillation. Its effect on myocardial flow, distribution, and performance. 80 60

A large number of clinical conditions are associated with a transient or permanent disturbance of brain function. Common to all of them is that, in some way, brain metabolism is changed from the normal. These changes cover a vast spectrum, ranging from the subtle alterations of metabolism encountered in mental disease to those underlying death and dissolution of cells in conditions of oxygen lack. This communication is concerned with brain metabolism in the critically ill with emphasis on conditions of hypoglycemia, hypoxia, and ischemia. We begin by briefly recalling the salient features of brain metabolism in the healthy individual. Since clinicians caring for critically ill patients take an interest in factors that may aggravate the primary disease and in measures that may prevent or minimize its final effect on the brain, we will also briefly consider how brain metabolism is influenced by potentially harmful factors (hyperthermia, anxiety and stress, and tissue acidosis due to CO2 retention) as well as by measures that are often instituted to ameliorate the effects of hypoxia and ischemia (hypothermia, administration of anesthetics and sedatives). We refer the reader to selected references with preference to recent articles reviewing previous literature.
 ...
PMID:Brain metabolism in the critically ill. 80 79

A procedure was developed in the laboratory for pancreatic allotransplantation in pancreatectomized dogs. Dogs with such grafts have survived for many months when treated with azathioprene and prednisone to prevent rejection. Contrary to usual beliefs, the pancreas is not unduly sensitive to total ischemia since it has been possible to successfully preserve a canine pancreas in vitro with hypothermia for periods up to 24 hours. Such preserved pancreas' have then been allotransplanted into pancreatectomized dogs with survival of the dogs for long periods. We have now done pancreaticoduodenal allotransplantation in 13 patients with juvenile onset diabetes mellitus. Nine of these patients also had renal failure and received simultaneously a renal allograft taken from the same cadaver. In all but one of these patients the pancreas functioned immediately. Two patients with juvenile onset diabetes mellitus and severe retinopathy but without terminal renal failure have received pancreaticoduodenal allografts alone. In both of these patients the pancreas functioned immediately but problems with the duodenum necessitated the removal of the pancreaticoduodenal allograft which did not show signs of rejection. As a result of the findings of increased sensitivity of the kidney and duodenum to rejection we have now modified our technique to transplant the pancreas alone. This technique was used in one patient with juvenile onset diabetes mellitus and severe retinopathy. Her renal function was only moderately reduced. The pancreatic allograft initially functioned normally but then was removed at 28 days because of clinical signs of rejection of the pancreas which were confirmed by the microscopic findings. Despite the promise of islet-cell transplantation, no long term functioning allografts have resulted in animals or man. Thus we need to continue with whole organ pancreatic allografts by various techniques if diabetes mellitus is to be controlled.
 ...
PMID:Transplantation of the pancreas. 82 66

This study compares the effects of normothermic and hypothermic spontaneous fibrillation at perfusion pressures of 100 and 50 mm. Hg on the adequacy and distribution of coronary blood flow. During normothermia (37 degrees C.), subendocardial oxygen delivery decreased 45 per cent ( p less than 0.01) and left ventricular flow became redistributed away from the subendocardium (endo-epi flow ratio fell from 1.2 to 0.8) when perfusion pressure was lowered to 50 mm. Hg; abnormal glycolysis (lactate washout) became evident when perfusion pressure was raised to 100 mm. Hg and ischemia was demonstrated by histochemical stains. Hypothermia (28 degrees C) reduced myocardial oxygen uptake 52 per cent (p less than 0.01) at 100 mm. Hg perfusion pressure; left ventricular flow, distribution, and metabolism did not change from control values. Lowering perfusion 50 mm Hg caused a pronounced reduction in subendocardial oxygen delivery (63 per cent, p less than 0.01); abnormal glycolysis developed and histochemical ischemia was seen. These studies show that lowering perfusion pressure in normothermic fibrillating hearts impairs oxygen delivery to the left ventricular subendocardium. While hypothermia significantly reduces left ventricular oxygen requirements, the ventricle is not protected against subendocardial ischemia if perfusion pressure falls to levels frequently used during clinical open-heart surgery.
 ...
PMID:Studies of the effects of hypothermia on regional myocardial blood flow and metabolism during cardiopulmonary bypass. III. Effects of temperature, time, and perfusion pressure in fibrillating hearts. 83 Sep 99

This study compares (1) the effects of slowing heart rate by topical hypothermia in hearts perfused at 37 degrees C. with bradycardia produced by perfusion hypothermia (28 degrees C.) and (2) the consequences of counteracting the bardycardic effects of perfusion hypothermia by atrial pacing. Topical atrial hypothermia (myocardial temperature 37 degrees C.) produced a level of bradycardia comparable to perfusion hypothermia (82 vs. 71 beats per minute), but reduced myocardial oxygen requirements 25 per cent more than perfusion with 28 degrees C. blood. Myocardial oxygen uptake per beat did not change with topical atrial hypothermia but increased 40 per cent with perfusion hypothermia. Counteracting the bradycardic effects of perfusion hypothermia with atrial pacing (to 130 beats per minute) reduced subendocardial flow 25 per cent, caused a redistribution of flow away from the subendocardium, and produced evidence of ischemia on the intracavitary electrocardiogram. This study shows that (1) topical atrial hypothermia with systemic normothermia reduced myocardial oxygen demands as effectively as perfusion hypothermia and (2) subendocardial ischemia develops in beating empty hearts when the expected bradycardia of hypothermia does not occur.
 ...
PMID:Studies of the effects of hypothermia on regional myocardial blood flow and metabolism during cardiopulmonary bypass. IV. Topical atrial hypothermia in normothermic beating hearts. 83 58

A total of 204 patients, ages 3 months to 84 years, underwent open-heart surgery with the aid of cardiopulmonary bypass with moderate hypothermia. For protection of the myocardium, cardioplegia was induced by washing out the coronary arteries with an iced, buffered, isoosmolar, potassium-based infusate. After aortic cross-clamping, the aortic root or individual coronary arteries were perfused with 500 to 2,000 c.c. of an aqueous solution (at zero to 4 degrees C.) containing 20 mEq. of potassium. Periods of ischemic arrest as long as 208 minutes have been well tolerated, with only two of the eleven hospital deaths considered heart related. Defibrillation occurred spontaneously in 41 per cent and after one shock in 47 per cent of patient, without apparent correlation between duration of ischemia and restoration of effective rhythm.
 ...
PMID:Myocardial protection with cold, ischemic, potassium-induced cardioplegia. 83 26

Transfemoral cannulation of renal vessels with the Seldinger technique has been used as well as routine angiography in the following urologic indications. 1. Hypothermic in situ perfusion of the kidney in difficult surgical procedures on the renal parenchyma, e.g., multiple stones, stag-horn calculi, benign and malignant tumors in solitary, residual or functionally residual kidneys. The advantages of this method are sufficient time for surgery, no contamination of blood and therefore excellent view by means of complete ischemia and good long-term results of the renal function. 2. Embolization of inoperable renal tumors to reduce tumor growth and control bleeding. The material used for embolization was a modified preparation of homogenized autologous muscle tissue. 3. Occlusion of the renal artery prior to tumor nephrectomy by a flow-guided balloon catheter in order to reduce the difficulty of the surgical produce, e.g., in massive carcinomatous infiltration of the hilus vessels. 4. Retrograde phlebography of the left internal spermatic vein in recurrent or persistent varicocele and in infertility with only insignificant or doubtful varicocele. The advantage compared with orthograde phlebography via plexus pampiniformis is the direct evidence that the venous reflux causes the varicocele. When the technique has been mastered transfemoral cannulation of the renal vessels can be used in routinely in the clinic Critical consideration of the indications, however, is necessary.
 ...
PMID:[Transfemoral cannulation of the renal vessels. Diagnostic and therapeutic use in urology (author's transl)]. 84 52

Necrotizing enterocolitis continues to be a perplexing problem in the newborn and, in particular, the premature. Its pathogenesis is controversial, although there are well established clinical risk factors. Three patients had necrotizing enterocolitis while under close clinical observation and monitoring, despite the fact that these patients were not at high risk for necrotizing enterocolitis. All three had necrotizing enterocolitis after hypothermia and total circulatory arrest--a complication which until now has not been reported. Because of the close monitoring, these patients provide a unique clinical setting which eliminates most of the etiologic factors that have been implicated in the pathogenesis of necrotizing enterocolitis. The onset of necrotizing enterocolitis shortly after total circulatory arrest and the selective ischemic organ damage observed suggest local perfusion inadequacy. The authors postulate that splanchnic vasoconstriction as a result of marked sympathetic stimulation contributes to this local ischemia and subsequent necrotizing enterocolitis.
 ...
PMID:Necrotizing enterocolitis after cardiac surgery: a local ischemic lesion?. 84 68


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