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991.
Rats were trained in a Y-maze on a two-choice simultaneous black-white discrimination with either black or white as S+. Animals were then transferred to one of three discrimination tasks. In task 1 (New S–), a new stimulus, either vertical or horizontal stripes, was substituted for the original S–. In task 2 (New S+), a new stimulus, either vertical or horizontal stripes as in task 1, was substituted for the original S+. In task 3 (New S+/S–) animals were trained on horizontal-vertical discrimination. The pre-trial administration of 1 mg/kg d-amphetamine facilitated the acquisition of the original black-white discrimination with both black as S+ and white as S+. Likewise, the drug improved performance in all three transfer conditions. However, the course of learning in the three transfer tasks was different in the placebo- and amphetamine-treated animals. Amphetamine-treated animals were disrupted more by a change in S+ than by a change in S–, whereas the opposite pattern was evident in the placebo controls. When both discriminative stimuli were changed, placebo animals exhibited pronounced decrement in performance, whereas amphetamine animals exhibited excellent learning. The implications of these findings for the effects of amphetamine on discrimination learning are discussed. 相似文献
992.
V M Kondrakov V I Koledenok P M Suvorov L I Arsen'eva 《Kosmicheskaia biologiia i aviakosmicheskaia meditsina》1987,21(4):67-69
The paper describes the examinations of 353 patients with various cardiovascular pathologies and changes in the end-portion of the ECG ventricular complex. For that purpose potassium chloride, obsidan, orthostatic and hyperventilation tests were used. The examinations demonstrated that the ECG changes were of functional nature in 178 patients, of organic nature in 155 patients and of mixed nature in 20 patients which was important for reliable diagnostic and expertise conclusions. 相似文献
993.
A simple circuit design is described which provides LED readout of transmitted and reflected pulsed rf power. The utility of monitoring these variables in physiological NMR studies is discussed. 相似文献
994.
Functional characteristics of intraepithelial lymphocytes from mouse small intestine. III. Inability of intraepithelial lymphocytes to induce a systemic graft-versus-host reaction is because of failure to migrate in vivo.
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In this study we have investigated whether addition of bone marrow accessory cells or concurrent administration of recombinant IL-2 would allow intraepithelial lymphocytes (IEL) to induce a systemic, lethal GvHR in irradiated hosts. In addition we have studied the ability of IEL to migrate into lymphoid tissues after intravenous injection and compared this with their locomotor capacity in vitro. 相似文献
995.
Congenital esophageal cysts in adults 总被引:1,自引:0,他引:1
Sixteen adult patients with congenital esophageal cysts were operated on between 1957 and 1979. Preoperatively, 7 patients (44%) were asymptomatic and the cyst was found incidentally on a routine chest roentgenogram. Esophageal symptoms were present in only 3 patients (19%), whereas most symptomatic patients had precordial sensations or arrhythmias. A correct preoperative diagnosis was made in only 1 patient. After enucleation of the cyst, preoperative symptoms were alleviated in all patients and short-term results were excellent. However, long-term follow-up 13.2 +/- 5.6 (+/- standard deviation) years later revealed moderate reflux in 9 (64%) of the surviving 14 patients. During esophagoscopy, macroscopic esophagitis was found in 12 (92%) of 13 patients. On histological examination of specimens obtained by forceps biopsy, esophagitis was present in 10 (77%) of 13 patients and included Barrett esophagus in 2. We conclude that, despite excellent early results, long-term follow-up of patients who undergo operation for congenital esophageal cysts is indicated because of the increased incidence of reflux esophagitis. 相似文献
996.
997.
The work gives substantiation of using complete intestinal lavage for certain indications in the complex treatment of incompetent colonic anastomoses. The method was efficiently used in 6 patients. 相似文献
998.
999.
D J Chambers M V Braimbridge D J Hearse 《European journal of cardio-thoracic surgery》1987,1(2):80-90
The isolated perfused working rat heart model of cardiopulmonary bypass was used to assess whether (a) allopurinol pretreatment enhances resistance to normothermic (30 min) or hypothermic (4 h) ischemia; (b) addition of antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) to cardioplegic and/or reperfusion solutions are protective; (c) any protective effects are additive. With normothermic ischemia, allopurinol pretreatment improved recovery of aortic flow from its control value of 25 +/- 3% to 48 +/- 6% (P less than 0.05). Similarly, SOD plus CAT used during both ischemia and reperfusion improved recovery of aortic flow from a control value of 28 +/- 4% to 48 +/- 6% (P less than 0.05). However, various combinations of the two types of intervention afforded no additive protection. Under hypothermic (21 degrees C) conditions, allopurinol pretreatment was not effective, whereas SOD and CAT added during ischemia and reperfusion improved recovery of aortic flow from its control value of 53 +/- 4% to 69 +/- 5% (P less than 0.05). This value was similar to allopurinol pretreatment and SOD plus CAT added during ischemia and reperfusion (69 +/- 6%: P less than 0.05). These results provide further evidence that reperfusion-induced free radical formation may adversely affect postischemic recovery of function. The absence of an additive effect suggests a common mechanism of action, which is likely to involve the free radical-generating enzyme xanthine oxidase; however, other mechanisms may exist. Our results further support the use of antifree radical intervention in conjunction with cardioplegia to protect the heart during ischemia and reperfusion. 相似文献
1000.