Biomedical subjects
Publications and source records attributed to J Novák.
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The ultrastructural changes of ring-shaped nucleoli in human blood lymphocytes produced with actinomycin D were compared with naturally occurring modification of ring-shaped nucleoli and micronucleoli in mouse thymic lymphocytic. Similarly to those in other nucleoli, these changes were characterized by the segregation of nucleolar components, appearance of very dense granular and fibrillar components, formation of dense plaques as well as dense nucleolar caps and nucleolar fragmentation. In addition, some of the observed changes were specific for the ring-shaped nucleoli i. e. formation of horse shoe-like and beaded nucleoli with the segregation of RNP components in the nucleolar peripheral ring. Some of the nucleolar changes produced with actinomycin D were also similar to the naturally occurring ultrastructural characteristics of micronucleoli in small mouse thymic lymphocytes.
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In the present paper the possibilities of scintigraphic diagnosis of experimental pericarditis are discussed. Pericarditis was induced by either talc or formaldehyde intrapericardially. In all animals the administration of talc as well as formaldehyde produced inflammatory changes which were more serious after formaldehyde. The scan of the talc pericarditis was carried out on the 7th day after operation and of the formaldehyde pericarditis on the 3rd, 7th or 14th days. No positive scintigraphic finding was made in any of the experimental animals, apart from a massive incorporation in the operation scars. The counting of radioactive impulses after the exstirpation of the tissue samples confirmed the scintigraphic findings. Statistical evaluation did not reveal any essential difference between the accumulation of the radiopharmaceutical into the pericarditis as well as into the pericardial bag in comparison with the control animals. Although our model does not exactly reflect the situation of patients suffering from pericarditis it may be assumed that pyrophosphate scintigraphy is not suitable for the diagnosis of acute pericarditis in clinical practice.
Scintigraphic examination of the myocardium using 99mTc-labelled pyrophosphate was carried out in 10 dogs with experimentally produced cardiomyopathy. This was brought about by intravenous administration of high doses of adrenalin and theophylline. The scan was positive in 8 out of 10 dogs. "Hot" foci were very extensive. The degree of accumulation was however low (2+). Histological examination of the myocardium using the light microscope showed only scarcely distinguishable damage to the tissue without the presence of necrosis. ECG examinations were normal in all cases. By means of 99mTc-labelled pyrophosphate even very small myocardial disorders can thus be detected. This fact may be of clinical importance for an early diagnosis of heart lesions.
In 9 dogs a transient myocardial ischemia was provoked using complete occlusion of the ramus interventricularis anterior of the left coronary artery. The occlusion was removed after 5, 10 or 15 min. Four hrs after removal of the occlusion a scan of the myocardium was carried out using 99mTc-labelled pyrophosphate. In 7 out of 9 dogs under study the scan was markedly positive, in 2 dogs negative. ECG demonstrated ischemic changes practically in all dogs; the changes became normal after removal of the occlusion, namely in 5 to 35 min. The histological examination of the tissue demonstrated in all 9 dogs only a slight impairment of the myocardium.
A survey is presented of research results of pyrophosphate myocardial scanning in 130 dogs and 150 patients with various myocardial lesions. The results of experiments in animals were immediately applied in clinical practice. The results showed that acute transmural myocardial lesions yielded practically in all instances positive scintigraphic findings. The findings in nontransmural infarctions were less convincing--they were positive in 60% of cases. Positive scintigraphic findings were also obtained in 80% of dogs with experimentally induced temporary ischaemia, and in 80% of dogs with experimentally induced dystrophy of the myocardium. In patients with angina pectoris positive findings were obtained in 1/3 of the cases, and in patients with cardiomyopathies, in 1/3 to 1/4 of the cases (in dependence on the etiology of the cardiomyopathy). It appears that 99mTc-PYP is a highly sensitive, but nonspecific, detector of myocardial lesions.
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Neuropsychiatrical symptoms occurring during the disease caused by burning are dealt with. Neuropathological alterations lying in the basis of these symptoms are discussed. Oedema of the brain observed in 7 cases out of 9 analysed neuropathologically is described in detail. Considering literary data and findings in the observed cases authors believe, that oedema of the brain plays a role in the mortality caused by burning.
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