Paraffin-embedded Liver Sections Research Articles

Failure to detect hypnozoites in hepatic tissue containing exoerythrocytic schizonts of Plasmodium knowlesi.

Sections of paraffin-embedded rhesus liver containing numerous nearly mature exoerythrocytic schizonts of the non-relapsing malaria parasite, Plasmodium knowlesi, were examined for the presence of hypnozoites by indirect immunofluorescence, employing both homologous and strongly cross-reacting heterologous sera. No hypnozoites or evident hypnozoite equivalents were detected in tissue which, by analogy with results obtained for the relapsing species, P. cynomolgi bastianellii, should have contained 35--50 of the uninucleate forms. These observations are presented as additional evidence in favor of the hypnozoite theory of malarial relapse.

Heterogeneous staining of rat hepatocyte nuclei by HBFP technique.

The non-enzymatic histochemical technique Haematoxylin--Basic Fuchsin--picric acid (HBFP) was studied in fresh-frozen and Carnoy-fixed, paraffin-embedded rat liver sections. The hepatocyte nuclei fell into two populations and showed either a crimson red or purple staining in frozen as well as paraffin sections. The heterogeneous staining of the rat heptocyte nuclei was also present when the tissue sections were stained by Methyl Green--Pyronin stain. The differing nuclear staining was present in the isolated nuclei also. The HBFP technique, therefore, appears potentially useful when applied to liver and other tissues as well.