Guinea pig hearts isolated by the Langendorff technique were perfused with a nitro-blue tetrazolium salt solution. In spite of a homogeneous dark-blue staining at the macroscopic examination, light-microscopic studies showed a spotty staining of the myocardial fibers. Since no microscopic alterations were found which could explain the unstained areas, ultramicroscopic studies were undertaken. At ultrastructural level, striking alterations of myocardial cells were observed. They consisted of mitochondrial lesions, alterations of the transversal tubuli, and intercalated discs. Arteriolar narrowing and capillary edema were found, suggesting that pathological changes in the microcirculation could be a possible reason for the spotty staining of the myocardial fibers. Some speculations on the nature and localization of the formazan granules are also reported.

Comparative histochemical studies with Tetrazolium salt solutions were performed on 25 human and 3 canine hearts. After perfusion of whole hearts with Tetrazolium solutions extensive unstained areas were observed which proved to be artefacts, since they reacted positively after incubation of the heart-slices. The perfusion method of Lichtig, Feldman, Glagov and Wissler (1973) which was proposed for macroscopic and microscopic diagnosis of ischemic cardiac lesions was not found to be suitable for the identification of microcirculatory disturbances. The usual incubation method, however, proved to be useful for the macroscopic localization of recent myocardial infarcts.

Os autores examinaram as lâminas de 264 casos preclassificados como Doença de Hodgkin, pertencendo 159 ao arquivo do Dep. de Patologia da Fac. de Medicina da UFRGS e 105 ao arquivo do Instituto de Patologia de Porto Alegre. Os casos foram classificados de acordo com as determinações da Conferência de Rye em Predominância Linfocitária, Esclerose Nodular, Celularidade Mista e Depleção Linfocitária. Destes 264 casos, 220 foram confirmados como Doença de Hodgkin e com a seguinte distribuição: 93 casos de CM; 55 casos de EN; 46 casos de DL; 11 casos de PL; e 15 casos não classificados. A incidência segundo a idade evidencia uma maior concentração da DH dos 05 aos 20 anos, sendo que 76% dos casos ocorrem antes dos 40 anos. Há uma predominância do sexo masculino, numa proporção de 2:1.91% dos casos pertencem a pessoas de cor branca. Em 66% dos casos a 1ª biópsia foi feita na região cervical, seguida das regiões axilar e ingüinal e cavidade abdominal. Por fim os autores comentam seus resultados em função de alguns aspectos epidemiológicos e metodológicos, comparando-os com os da literatura.