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991.
The effects of manganese chloride (MnCl2) and verapamil on automaticity of digitlazied Purkinje fibers were studied using conventional microelectrode techniques. The stduied wer made in isolated, spontaneously beating Purkinje prearations. Quabain alone consistently increased the automatic rate, whereas no such increase was observed when the preparations were superfused with a mixture of ouabain adn MnCl2. MnCl2 was also shown to be effective is suppressing the enhanced automaticity induced by ouabain. Mncl2 alone did not have a significant effect on the spontaneous rate of Purkinje fibers. The effect of verapamil was similar to that of MnCl2 in preventing and suppressing the ouabain-induced increase in automaticity. MnCl2 and verapamil have been shown to inhibt tha slow inward calcium current of cardiac fibers. The results therefore suggest that an inward calcium ion current may play a role in the development of digitalis-induced increase in the stope of phase 4 depolarization in Purkinje fibers. 相似文献
992.
993.
A young child with severe mental retardation, skeletal abnormalities and the phenotypic appearance typical of a mucopolysaccharide disorder was found to have a previously unrecognized form of mucopolysaccharide storage disease. Mucopolysaccharide was found to accumulate in perichondrium, coronary arteries, aorta and the glomerular epithelial cells of the kidney; the reticuloendothelial system remained free of mucopolysaccharide. Lipid accumulation was observed in peripheral neurons but not in central neurons. Skin fibroblast cultures accumulated 35SO4 to an extent intermediate between normal cell lines and those from patients with classic mucopolysaccharide storage disorders. 相似文献
994.
The hemodynamic response to diaphragm pacing was studied in eight patients with Ondine's Curse. It was shown that such pacing could lower the pulmonary artery pressure while correction of hypoxemia alone could not. It was demonstrated that on pacing, calculated pulmonary arteriolar resistance decreased and there was normalization of arterial blood gases. The mechanism for these changes was improved alveolar ventilation. 相似文献
995.
W H Frishman J Christodoulou B Weksler C Smithen T Killip S Scheidt 《American heart journal》1978,95(2):169-179
Data collected before the initial reports of myocardial infarction following sudden withdrawal of propranolol are presented here to evaluate possible mechanisms for this phenomenon. Twenty patients with angina pectoris were randomized into placebo and propranolol (160 mg./day) treated groups and followed for 50 weeks at which time treatment was abruptly discontinued. Measurements of exercise tolerance, the product of heart rate and blood pressure at exercise end-point (HR × BP), and platelet aggregation thresholds in response to ADP and epinephrine were made before, during, and after treatment. Prior to propranolol, mean total work performance was 765 ± 125 k.p.m., HR × BP (heart rate-blood pressure product) was 16,800 ± 1,535. Mean platelet aggregation threshold with ADP was 1.32 μM1; with epinephrine 1.26 μM1. Patients treated with propranolol demonstrated significant improvement in exercise performance (1,790 ± 285 k.p.m., p < .01), reduction in HR × BP (12,000 ± 895, p < .01), and an elevation in platelet aggregation threshold; with ADP 3.43 μM1 (p < .01); with epinephrine 12.9 μM1 (p < .01). Following abrupt cessation of propranolol, exercise tolerance and HR × BP fell below pretreatment levels (630 ± 117 k.p.m. and 15,500 ± 513, respectively). Similarly platelet aggregation threshold fell to 1.0 μM1 with ADP and 0.57 μM1 with epinephrine. In six patients platelets were significantly more hyperaggregable than prior to therapy. Anginal frequency increased in all, but no acute infarction was observed. Abrupt withdrawal of propranolol may be deleterious in patients, sometimes causing “rebound” platelet hyperaggregability associated with increasing anginal frequency and decreasing exercise tolerance. 相似文献
996.
997.
D A Conetta E A Geiser D J Skorton N G Pandian R E Kerber C R Conti 《The American journal of cardiology》1984,53(9):1374-1379
Echocardiographic cross-sectional areas of 10 formalin-fixed animal left ventricles were determined by 5 independent observers using black-white (B-W) and mid-spot (M-S) endocardial boundary identification techniques. The echocardiographic cross-sectional areas were compared with the true anatomic cross-sectional areas of the same 10 hearts to determine the accuracy, variability and reliability of each technique. The results of these comparisons revealed that the M-S technique was more accurate than the B-W technique (3.3 +/- 7.2 vs 34.9 +/- 8.6% error). However, the B-W technique was more reliable in that it had a smaller interobserver and estimated intraobserver variability. The M-S technique had a 6% greater intraobserver variability. 相似文献
998.
Previous investigations in our unit indicated that acute cardiogenic pulmonary edema is associated not only with an increase in left ventricular end-diastolic pressure and pulmonary arterial wedge pressure but also with a relative increase in colloid osmotic (oncotic) pressure and peripheral hemoglobin concentration. This combination of changes suggested that acute congestive heart failure with pulmonary edema, unlike chronic congestive heart failure, is associated with a contraction of intravascular blood volume. In this study, plasma volume changes were measured before and during the treatment of acute cardiogenic pulmonary edema in 14 patients with arteriosclerotic heart disease. The plasma volume measurement in all 14 patients before the initiation of treatment was either normal or decreased. After treatment with the alpha adrenergic blocking agent phentolamine, the plasma volume increased rather than decreased when measured 4 and 12 hours after the initiation of treatment. During this time colloid osmotic pressure and peripheral hemoglobin concentration progressively decreased. These findings suggest that acute cardiogenic pulmonary edema is associated with the extravasation of large quantities of plasma water from the intravascular compartment into the interstitial compartment and contraction of the intravascular plasma volume. The treatment of acute cardiogenic pulmonary edema is associated with the return of hypo-oncotic fluid from the interstitial compartment back into the intravascular compartment with expansion of plasma volume and reduction of colloid osmotic pressure and hemoglobin concentration. 相似文献
999.
Cesar A. Conde MD Jose Meller MD Ephraim Donoso MD FACC Simon Dack MD FACC 《The American journal of cardiology》1975,35(6):912-917
A case is presented of bacterial endocarditis with a ruptured sinus of Valsalva and formation of an aorticocardiac fistula from the right coronary sinus into the right atrium and right ventricle. The pathologic, clinical and surgical aspects of bacterial endocarditis complicated by a ruptured sinus of Valsalva and an aorticocardiac fistula are analyzed. This complication of bacterial endocarditis is still uncommon, but alertness to its diagnosis makes possible early and successful surgical treatment. 相似文献
1000.
L De Marinis A Mancini S Minnielli R Masala C Anile G Maira A Barbarino 《Metabolism: clinical and experimental》1985,34(10):917-922
Recently, it has been shown that patients with a PRL-secreting pituitary adenoma have a greater thyroid stimulating hormone (TSH) release after dopamine (DA)-receptor blockade than normal subjects. We have compared the TSH and PRL responses to metoclopramide (MCP) in normal and postpartum lactating women with those in 28 patients with hyperprolactinemia of different origin. Patients with a PRL-secreting pituitary adenoma were also tested after transsphenoidal removal of the tumor in order to establish the prognostic value of this test in such patients. Following MCP administration, percent increases in plasma PRL levels were greater in normal female subjects than postpartum lactating women. Plasma TSH levels did not increase in postpartum women and had a modest increment in normal subjects. In patients with hypothalamic tumors and empty sella syndrome plasma PRL and TSH levels showed modest or no increases after MCP administration. In ten patients harboring a microprolactinoma, plasma TSH levels showed an exaggerated increment after DA-receptor blockade. Postoperatively, despite normal or borderline PRL levels in the immediate postoperative period, a TSH response to MCP was present (in five patients one to two weeks after the operation, and in five patients one to three years after the operation), suggesting an increased DA activity even in the absence of hyperprolactinemia. In conclusion, the TSH test can easily detect increased DA-activity in patients with a microprolactinoma both preoperatively and postoperatively. It is possible that some patients with increased DA-activity in presence of normal PRL levels and normal PRL responsiveness to stimulation will experience a recurrence of hyperprolactinemia.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献