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Query: UMLS:C0020672 (hypothermia)
 17,327 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies utilizing in vitro microperfusion were designed to examine whether urea is actively or passively transported across superficial and juxtamedullary straight segments of rabbit proximal tubules. With perfusate and bath solutions containing 1 mM urea and electrolytes similar to normal plasma, the efflux (lumen-to-bath) isotopic permeability (X 10(-5) cm s-1) of superficial segments was 1.37 +/- 0.16 and of juxtamedullary segments was 2.14 +/- 0.20. In the same tubules, the influx (bath-to-lumen) isotopic permeability was 3.70 +/- 0.35 in superficial segments and 4.75 +/- 0.37 in juxtamedullary segments. Despite net water movement in the opposite direction (0.5 nl mm-1 min-1), the influx rate was significantly higher than the efflux rate of urea in both groups. With a low perfusion rate (2 nl/min) and equivalent specific activities of [14C]urea in bath and perfusate, the collected-to-perfused ratio of [14C]urea, corrected for volume marker change, was 1.07 +/- 0.01 in superficial and 1.09 +/- 0.01 in juxtamedullary nephrons, thus indicating net secretion in both segments. In separate studies urea influx was inhibited by hypothermia (decrease from 37 degrees to 28 degrees C), by phloretin (0.1 mM in bath), by cyanide (1 mM), but not by probenecid (0.2 mM). In each case the inhibition was highly significant and reversible. These data suggest that urea is actively secreted by the straight segments of both the superficial and juxtamedullary proximal tubules. These segments may, therefore, contribute significantly to the high urea concentration found at the bend of Henle's loop by micropuncture.
J Clin Invest 1976 Sep
PMID:Urea secretion by the straight segment of the proximal tubule. 95 89

An unusual case of a patient surviving a bilateral congenital anomaly of the major renal conduits is presented. Anatomical features of this case, considered with present embryological ideas in mind, support the concept of a continuum of disorders of the major renal conduits. The literature is reviewed and interesting microsurgical techniques with hypothermia enabling reconstruction of the collecting systems and renal preservation are discussed.
J Urol 1976 Sep
PMID:Hypoplasia of the major renal conduits. 95 6

We present a new approach for anatomic correction of transposition of the great arteries. The two coronary arteries, with a piece of the aortic wall attached, are transposed to the posterior artery. The two aortic openings are closed with a patch. The aorta and pulmonary artery are transected, contraposed, ant then anastomosed. The interventricular septal defect is closed with a patch, through a right ventriculotomy approach, because the right ventricle is no longer part of the systemic circulation. Two patients, aged 3 months and 40 days weighing 4,200 and 3,700 grams, respectively, were operated upon with deep hypothermia and total circulatory arrest. There was good recovery from the operation, with normal cardiocirculatory conditions. Renal failure developed in the first patient, and she died on the third postoperative day. During this time the cardiocirculatory conditions were good. The second patient made an uneventful recovery. Hemodynamic studies 20 days after the operation showed complete correction of the malformation. Five and one-half months after the operation, he weighs 7,500 grams, and his development is very good. We believe that this operation will be reproducible by most cardiovascular septal defect and pulmonary hypertension.
J Thorac Cardiovasc Surg 1976 Sep
PMID:Anatomic correction of transposition of the great vessels. 95 54

The technique of preferential cerebral hypothermia is reported in its application to a patient with a "giant" anterior communicating artery aneurysm. The method utilizes elective ventricular fibrillation and differential or "preferential" hypothermia induced by a combination of external skin cooling and perfusion of core organs with 0 degree buffered electrolyte solution. The value of the technique lies in its provision of a period of safe circulatory arrest approaching one hour without the need for anticoagulation, heart-lung bypass, open chest resuscitation or major vessel clamping. Because of the absence of blood flow and because of the clear fluid washout of the cerebral vessels, it was possible to open the aneurysm, evacuate its contents and resect it in several sections. It was not necessary to clip the feeding arteries until all dissection and total removal of the aneurysm were completed. The application of the technique to neurosurgery and cardiovascular surgery is discussed.
Surg Neurol 1976 Sep
PMID:Preferential cerebral hypothermia with elective cardiac arrest: resection of "giant" aneurysm. 95 90

Ventricular septal defect repair had been performed in 57 infants ages 21 days to 21 months and under 10 kg in weight using profound hypothermia-circulatory arrest technics. Severe congestive heart failure was the indication for operation in all but two infants under 6 months of age, and in those under 3 months there was usually an associated moderate or large sized atrial septal defect or patent ductus arteriosus or a coarctation. In infants over 6 months controlled heart failure was accompanied by failure to thrive and often recurrent respiratory infections. The main indication for surgery in three infants was repeated severe respiratory infections and in 7 infants, ages 10-15 months, an elevation of pulmonary vascular resistance of 6 units M2 or more. There were two hospital deaths among the 49 infants without coarctation (ages 6 and 20 months) and two among the 8 with coarctation. Postoperative respiratory and other complications were uncommon. On late review there was no significant residual VSD amongst the 11 recatheterized patients. Psychometric studies in 19 children who had reached the age of three to four years gave no evidence of cerebral damage due to the circulatory arrest period. In view of these results palliative pulmonary artery banding is no longer performed for VSD in infancy unless there is a Swiss cheese septum or an associated severe coarctation.
Ann Surg 1976 Sep
PMID:Repair of ventricular septal defect in the first two years of life using profound hypothermia-circulatory arrest techniques. 96 2

A total of 74 patients under 24 months of age with large ventricular septal defects (VSD) and pulmonary hypertension were subjected to surgical treatment from 1969 through 1975. Emergency pulmonary artery (PA) banding was performed in 13 patients during the first year of life with 1 death from postoperative respiratory failure. Primary closure of the VSD was performed in 61 patients using simple hypothermia and short-term coronary perfusion, with an operative mortality of 1.6%. There were no late deaths or neurological disturbances. Normal hemodynamic data were obtained in all 7 patients who underwent postoperative cardiac catheterization from one month to five years after the primary correction. It is concluded that primary closure of a VSD in infancy is reasonable and that PA banding is indicated only for those patients less than 6 months old with a complicated defect or in an emergency situation.
Ann Thorac Surg 1976 Sep
PMID:Surgical treatment of large ventricular septal defect with pulmonary hypertension in the first 24 months of life. 96 6

The authors examined in 25 patients, of which 15 were normo- and 10 in hypothermic, the cardiovascular effects of 1 mg atropine i.v. In normothermia the heart rate increased significantly from 100 to 110 beats/min after atropine. At the same time the stroke index and stroke work decreased significantly. The mean arterial pressure, the heart index, the left ventricular minute- and stroke work and the total peripheral resistance did not change. In two patients with an arteriovenous fistula and hypervolaemia, the atropine injection caused an increased of heart- and stroke index. Arrhythmias did not occur after atropine. In hypothermia on the other hand atropine was shown to have no effect on heart frequency and all other examined parameters. In one patient in which the P-R interval was shortened, the atropine injection was followed by an total atrio-ventricular block. The authors cannot recommend atropine therapy in cases of hypothermic bradycardia, because of its lack of effect on the heart rate in hypothermia.
Anaesthesist 1976 Sep
PMID:[Cardiovascular changes caused by atropine in normo- and hypothermic methoxyflurane anaesthesia (author's transl)]. 97 May 97

The effect of prolonged light halothane anesthesia (0.8%) on the proliferation rate of different mouse tissues was investigated, using [5-125I]5-iodo-2-deoxyuridine uptake into DNA as the test parameter. It was found that DNA synthesis in spleen, femoral bone marrow, and, occasionally, the small intestine was significantly depressed after exposure for 24 hr to halothane in vivo. The time course of DNA synthesis inhibition was then investigated by utilizing a shorter (6-hr) exposure time. This period was found to be insufficient to cause DNA synthesis inhibition in any of test tissues. Because anesthesia was found to be associated with hypothermia at normal room temperatures, it was established that the inhibition of DNA synthesis was not due to cooling of the mice under anesthesia by demonstrating that inhibition in sensitive tissues occurred at warmer temperatures as well. To examine the specificity of this finding, the DNA synthesis rate of cells in other normal tissues, e.g., skin and muscle, and in s.c.-growing tumor cells of a mouse mammary carcinoma, L1210 leukemia, and a first transplant AKR lymphoma were examined. In none were responses noted with 24 hr of halothane exposure. However, halothane was found to inhibit DNA synthesis in regenerating marrow. Finally, it was found that after significant exposure to halothane, complete recovery was seen in the spleen after 24 hr, whereas femur DNA synthesis was still depressed by 20% at the same time.
Cancer Res 1976 Sep
PMID:Preferential inhibition of DNA synthesis in mouse hemopoietic cells by halothane. 97 81

Hypothermia (4 degrees C) reversibly inhibits metabolism of prostaglandin A1 (PGA1) in the perfused rabbit lung and decreases the transit time of PGA1 through the lung. Co-perfusion of PGA1 (0.28 muM) and PGE1 (2.8 muM) resulted in 48% inhibition of PGA1 metabolism. Ouabain and phenoxybenzamine (10(-5) M) did not significantly affect PGA1 metabolism. We examined the effect of diphloretin phosphate (DPP; 6.0 mu/ml) on the metabolism of prostaglandin A1 (0.28-5.03 muM) and E1 (PGE1;0.28-11.56 muM). The metabolism of both prostaglandins appeared to be saturable processes and, in the case of PGE, the data conformed to Michaelis-Menten kinetics: the apparent Km (muM) and apparent Vmax (nmol/lung X min-1) in control lungs were 9.0 +/- 0.3 and 87.9 +/- 1.4, respectively, and in the DPP-treated lungs were 9.6 +/- 0.5 and 57.7 +/- 1.8. This suggests that DPP acts in a noncompetitive manner. The magnitude of inhibition of PGA1 and PGE1 metabolism (both at 0.28 muM) was linearly related to the DPP concentration, over the range of 0.06 to 25.0 mug/ml. The ID50 values of DPP inhibition of PGA1 and PGE1 metabolism were 2.2 and 8.4 mug/ml, respectively. Perfusion of PGA1 at 2.96 muM or higher concentrations caused reversible vasoconstriction which was significantly inhibited (P less than .05) by DPP (6.0 mug/ml) by an average of 77.2 +/- 5.8% (n = 7).
J Pharmacol Exp Ther 1976 Sep
PMID:Metabolism of prostaglandins A and E in the perfused rabbit lung and the effects of selected inhibitors. 97 71

Nine-day-old S-W mice receiving deep body hypothermia or hyperthermia immediately after escape training were retested 1 or 24 hr later. Results indicated that hypothermia impaired 24-hr retention but had no effect upon 1-hr memory. Hyperthermia had no effect, with the mice demonstrating retention of the escape response at both retest intervals. In Experiment 2, administration of hypothermia or hyperthermia 23 hr after original training had no effect upon memory nor did either treatment produce motoric deficits upon retest 1 hr following thermal exposure. Experiment 3 indicated that hypothermia administered immediately after training produced retention deficits directly related to amount of body temperature reduction following hypothermia. These data are similar to those obtained with adult mice and suggest that memory processes occurring in 9-day-old mice may represent the onset of functioning of processes underlying adult long-term memory.
Dev Psychobiol 1976 Sep
PMID:Hypothermia causes adult-like retention deficits of prior learning in infant mice. 98 75


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