[Type II atrial septal defects in adulthood]. / Defekty sínového septa II. typu v dospelosti.

Indication criteria of adult patients with atrial septal defects type II for surgery are not uniform so far. In a group of 150 adult patients with atrial septal defects type II operated in 1978-1987 at the cardiosurgical department in Brno the authors report the following results: a mortality on operation of 0.7% and a very satisfactory postoperative condition in almost all patients. In a group of 16 patients examined in 1978-1987 but not operated because of a defect of the atrial septum type II of minor haemodynamic impact the authors observed after long-term follow up a deterioration of the health status in four patients and they express therefore doubts on the rigorous criterium for operation a 1.5:1 left-to-right shunt in adult patients and assume that in some instances the defect is indicated for surgery even when the shunt is small.

A T-helper/suppressor ratio in renal allograft recipients after various long-term immunosuppressive regimens.

The response of T-helper and T-suppressor cells to various immunosuppressive regimens was studied in long surviving cadaveric renal allograft recipients. Eight patients were immunosuppressed with Azathioprine and corticosteroids, 12 recipients were treated with a combination of Cyclosporin A, corticosteroids and Azathioprine for 1 year. Both regimens decreased the Th/Ts ratio significantly as compared with healthy controls (p less than 0.05). No correlation between the Th/Ts ratio and the serum creatinine concentration was found. Likewise, the Th/Ts ratio did not correlate with Cyclosporin A blood levels.

Surgical aspects of the implantation of a left ventricle assist device.

The authors have summarised their experience with short-term use of a left ventricle assist device (LVAD). Nine experiments were carried out in healthy calves. A polyurethane pump of their own design, placed extracorporeally, was used. Its in-flow cannula was placed in the left atrium, the outflow one in the initial segment of the descending aorta. The LVAD was operated for a period of 5 days. Fourteen days after its disconnection, the animal was sacrificed and both the bypass system and parenchymal organs were examined. No surgical complications were observed during the experiments. Macro- and microscopical pictures showed minor infarctions in the renal tissue which, however, did not impair renal function. The findings in other organs were related to anaesthesia, the operative procedure and way of animal sacrificing. The experiments have proved the safety of the bypass system used over a short period and, consequently, its potential for future clinical application.

Innervation of atrial stumps in calves living with the TNS-Brno II artificial heart.

The remnant stumps of the atria in six calves surviving with the artificial TNS-Brno II methacrylate heart for up to 5 months were examined by means of the Bodian silver-impregnating technique and by the formalin-induced fluorescence technique visualizing noradrenaline in monoaminergic nerve terminals. The degeneration of the nerve terminal system detected in animals surviving for 2 days and 1 week was followed by regeneration of the vegetative nerve system in four animals surviving for greater than 1 month. Moreover, thick myelinated nerves afferent in character were detected within the atrium of one animal surviving for 5 months.

The occurrence of chronic rejection and biliary sludge in long-surviving pigs after liver transplantation.

Autopsy and histological findings in the livers of pigs long-term surviving liver orthotopic allotransplantation indicate that there is no correlation between chronic rejection of the graft and the presence of biliary sludge in the bile tract.

The border zone of the early myocardial infarction in dogs; its characteristics and viability.

In open-chest dogs, the left anterior descending coronary artery was ligated for 150 min. The heart was semiserially cut on a cryomicrotome and areas of ischemic damage were visualized by means of glycogen depletion (PAS reaction) and tissue acidosis (a "sandwich" technique with pH indicator dispersed in a layer of gel). The extent of myocardial damage was determined morphometrically. The mass of the glycogen-depleted heart muscle was greater than the mass of the ischemic tissue detected by means of decreased pH (p less than 0.01). The border zone was characterized by glycogen depletion without acidosis. Circulation studies using intravital fluorescein staining have shown that perfusion is partially retained in the border zone; it is assumed that the hypoperfusion triggers glycogenolysis. Nevertheless, the level of perfusion suffices to wash out the acidic end products. Comparison of contrapulsation-treated dogs and untreated dogs shows that the amount of damaged tissue comprising the border zone can be reduced by this therapeutic intervention (p less than 0.02) - in contrast to the acidotic tissue, the amount of which is not significantly influenced. Therefore the border zone contains damaged but still viable muscle cells.

Mechanisms causing the death of 8 calves surviving with implanted artificial heart from 31 to 173 days.

Causes of the death of four animals from the total of eight were technical failures (diaphragm perforations, disconnection of the quick-connector, and a failure of the supply of electric current which could not be prevented). Causes of the death of the remaining four animals were embolisation in the brain stem, embolisation in the superior mesenteric artery leading to diffuse peritonitis, ruptures of aorta and hemocoagulation disorder causing fatal gastrointestinal bleeding.

Reperfusion of coronary arteries after temporary occlusion in dogs.

The influence of previous pharmacotherapy or intra-aortic balloon counterpulsation (with thiamine infusion) on the effectiveness of reperfusion of the left anterior descending (LAD) coronary artery after 150 minutes of occlusion has been studied in dogs. The infarct size was determined by morphometric method 20 hours after the onset of ischaemia. Reperfusion 150 minutes after the occlusion of the LAD coronary artery resulted in a smaller infarct; however, no protective effect from pharmacological or mechanical heart support during the period of ischaemia was observed.

Interaction of DNA and deoxyribonucleoprotein with methylene blue. Influence of acid fixation and pretreatment used in chromosome G-banding techniques.

Influence of fixation and so-called pretreatment procedures used in visualization of chromosome G-bands on staining capacity of isolated biopolymers in solution and on chromatin of cell nuclei was investigated. Whereas acid fixation as well as pretreatment procedures generally decreased the maximum binding capacity of isolated DNA and DNP for methylene blue, the dye content in acid-fixed nuclei was increased as compared with chromatin of neutral-fixed and non-fixed nuclei. The role of dehistonization and aggregation in an acid medium on the dye-binding properties of these two types of DNP was examined and the relation of higher-order structure of chromatin to its staining properties as reflected in G-banding pattern was discussed.

[Cystic degeneration of adventitia]. / Cystická degenerace adventicie.

A description is presented of the cystic degeneration of the adventitia of the external iliac and femoral arteries. Numerous cysts in the adventitia compressed the arterial lumen and resulted in thrombotic occlusion. The histologic picture was similar to that of tendinous sheath ganglion. A list is given of cases already described with a discussion of the views concerning its aetiology and pathogenesis.

Suppression of the progress of necrosis after coronary artery ligation in the dog by pharmacologic interventions.

A study was carried out of a therapy supporting the anaerobic glycolysis and coronary perfusion of ischemic myocardium and preserving its potassium and magnesium contents, which consisted in combined administration of hyaluronidase, glucose, insulin, Tris, methoxamine, and potassium and magnesium aspartate. The drugs were administered to Beagle dogs between 30 minutes and 20 hours after the ligation of the left anterior descending coronary artery. The size of infarction was determined by the Nachlas method, which is based on the detection of activities of dehydrogenases in heart slices. Treated animals showed a reduced infarction size (p less than 0.001). The evidence of the favourable effect of the therapy used was brought also by hemodynamic measurements. The heart rate was slower (p less than 0.02) and the mean arterial blood pressure was higher (p less than 0.001) in treated animals than in control ones (as evaluated at the end of the experimental period). Significant correlation between the infarction size and the heart rate on the one hand and the mean arterial pressure on the other hand was found (r = 0.59, p less than 0.01; r=--0.47, p less than 0.05, respectively).

Interaction of DNA and deoxyribonucleoprotein with methylene blue after the treatment with fixation solutions used in chromosome G-banding techniques.

Maximum binding capacity of calf thymus DNA and deoxyribonucleoprotein for methylene blue was investigated. The binding capacity of native and heat-denatured solutions of the biopolymers was compared with that of the solutions incubated with fixatives used in cytology, viz. 4% formaldehyde and methanol-acetic acid (3 : 1) mixture. The binding capacity of DNA and DNP is strongly reduced after the treatment with both fixation agents. Thermal denaturation leads to a small decrease in the binding capacity of DNA, but does not influence that of DNP. These results were compared with microphotometric determination of nuclear methylene blue content in thymocyte spreads. Fixation with MeAc increased the dye content as compared with air-dried thymocytes, whereas 4% formaldehyde exhibited practically no influence. The mechanisms connected with the different staining properties after incubating with fixation agents DNA and DNP solutions on the one hand and the nuclear material of thymocyte spreads on the other hand are discussed.