These results show that glimepiride maintains myocardial preconditioning, while glibenclamide might be able to prevent it.

We investigated the morphologic structure and fluid content of atherosclerotic specimens of fresh human postmortem artery segments before and after application of a pressure of 5 atmospheres simulated by a weight of 5 kg per 1 cm2. After applying pressure in nonorganized atheromata, we noticed a marked reduction in thickness while in fibrotic atheromata we observed only smaller differences in thickness. Reduction in fluid content was significantly more pronounced in nonorganized atheromatous tissue. Reduction in thickness was closely related to reduction in weight (i e, fluid content). The time of pressure application necessary to achieve the optimal result averaged 60 sec. The conclusions drawn from these experiments were incorporated into clinical application of coronary angioplasty. Prolonged balloon inflation was applied to the last 400 out of a total of 600 coronary angioplasty procedures, performed between October 1977 and October 1983. Stenoses not sufficiently responsive to balloon inflation periods of 5-10 sec were exposed to periods of 60 sec (30-120 sec). The number of "non dilatable" stenoses was 15% with the standard short pressure procedure, but only 5% with the prolonged pressure application. No serious complications related to prolonged pressure application were observed. Thus, from experimental data and clinical experience the application of longer pressure periods appears justified and beneficial.

Cardiac transplantation entails surgical disruption of the sympathetic nerve fibres from their somata, resulting in sympathetic denervation. In order to investigate the occurrence of sympathetic re-innervation, neurotransmitter scintigraphy using the norepinephrine analogue iodine-123 metaiodobenzylguanidine (MIBG) was performed in 15 patients 2-69 months after transplantation. In addition, norepinephrine content and immunohistochemical reactions of antibodies to Schwann cell-associated S100 protein, to neuron-specific enolase (NSE) and to norepinephrine were examined in 34 endomyocardial biopsies of 29 patients 1-88 months after transplantation. Anterobasal 123I-MIBG uptake indicating partial sympathetic re-innervation could be shown in 40% of the scintigraphically investigated patients 37-69 months after transplantation. In immunohistochemical studies 83% of the patients investigated 1-72 months after transplantation showed nerve fibres in their biopsies but not positive reaction to norepinephrine. Significant norepinephrine content indicating re-innervation could not be detected in any biopsy. It was concluded that in spite of the lack of norepinephrine content there seemed to be immunohistological and scintigraphic evidence of sympathetic re-innervation. An explanation for this contradictory finding may be the reduced or missing norepinephrine storage ability compared to the restored uptake ability of regenerated sympathetic nerve fibres.

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Summary:It is known from experiments that angiotensinconverting enzyme inhibitors can limit infarct size. In a prospective. randomized, placebo-controlled double-blind study, 22 patients were given 1.5-2.0 mg captoprilh I.V., while 24 patients were given placebo. Medication was started between 2 and I8 h from the onset of infarction. The two groups were matched for age, infarct location, and time of intervention. With the exception of one patient in either group, all were concurrently given nitroglycerin. The necrosis parameters were provided by the quantitative measurement of the QRS complex. The Q wave decreased with captopril treatment (-0.003 mV), but increased with placebo (+0.14 mV, p < 0.05). The number of ventricular premature beats at 24 h from the start of treatment was 2 5 h with placebo, and 9/h with captopril (p < 0.02). Ventricular fibrillation occurred seven times in the placebo group, but did not occur in the captopril group. The creatine kinase infarct weight was 59 gram-equivalents (gEq) with placrebo, and 45 gEq with captopril (p = NS). Mean arterial pressure was reduced by 12 mmHg with captopril treatment. The results show a beneficial effect of captopril on infarct size and electrical instability, over and above the effect of standard management with nitroglycerin and thrombolysis.

We describe a fully automated method for quantification of left ventricular performance by equilibrium radionuclide ventriculographic studies, based on subdivision of the left ventricular region into 9 equiangular sectors. The precise identification of the left ventricular contours is achieved by the use of morphological and functional criteria in a sequential edge detection algorithm with a success rate of 96%. In addition to left ventricular global and sectorial ejection fraction the first harmonic of the corresponding Fourier spectrum is approximated to each sectorial time-activity curve and to the global one. Sectorial phase is calculated as the difference between the phase of the sectorial and global first Fourier component. Computerized comparison between the sectorial parameters at rest and during peak exercise localizes and classifies the degree of global and regional impairment in response to exercise. The processing time of 60 sec makes this method suitable for routine use. The validity of our procedure has been tested in 34 patients before and after successful transluminal coronary angioplasty. In these patients, 73% of the stenosed vessels before dilatation were localized by sectorial ejection fraction, 77% by sectorial phases, and 88% by the combination of both.

Iodine-123 metaiodobenzylguanidine (MIBG) is a noradrenaline analogue which can be used as a tracer to investigate the cardiac sympathetic nervous system. Regional ischaemia leads to noradrenaline depletion with functional denervation which can be demonstrated by reduced MIBG uptake. In order to evaluate the reversibility of ischaemia-associated damage to the sympathetic nervous system, neuronal scintigraphy with 123I-MIBG and myocardial rest and stress perfusion scintigraphy with technetium-99m sestamibi was performed in 16 patients with coronary artery disease before and 3-4 months after percutaneous transluminal coronary angioplasty (PTCA). Partial re-innervation occurred in five patients, the degree of stenosis of remaining lesions being estimated by repeat angiography to be below 40%. Unchanged MIBG defects could be confirmed in four patients with residual lesions of between 40% and 50%. Increased MIBG defects were shown in three patients with significant restenoses of more than 70%. In all patients the neuronal defects exceeded the ischaemia-induced or scar-associated perfusion defects. Three patients dropped out of this study: one for technical reasons, one due to emergency aortocoronary bypass surgery and one due to diabetic polyneuropathy. This investigation shows that the sympathetic nervous system is highly sensitive to ischaemia. Further studies need to be done to assess the conditions allowing re-innervation after PTCA.

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