Histopathological and immunological studies of nasopharyngeal carcinoma.

From 1968 to 1973, 793 cases of nasopharyngeal malignancies in Japan were examined histopathologically and immunologically. The majority of the carcinomas were undifferentiated squamous cell carcinomas, including transitional cell carcinoma and lymphoepithelioma. These findings correspond well with those of other countries. There were more well differentiated carcinomas in the old than in the young age groups. The positive rate (80%) and the geometric mean of the anti-VCA-antibody titers (more than 1:750) were remarkably high in the lymphoepithelioma group. These two factors seem to be very important to the study of oncogenesis of nasopharyngeal carcinoma (NPC). The relationship between subpopulations of peripheral lymphocytes in NPC and histopathological classification was investigated. The lymphoepithelioma group had a higher proportion of B cells (complement receptor cells) to T cells (erythrocyte rosette forming cells) than healthy persons throughout the clinical course, and its prognosis was not good.     

Relationship between the ATPase activity and the ATP-induced fluorescence enhancement of SH-modified heavy meromyosin during its fractional inactivation by vanadate plus ADP: evidence for heterogeneity in the active sites

We have examined whether heavy meromyosin (HMM) consists of a single kind of active site by analyzing the changes in the relative MgATPase activity and the relative amplitude of the ATP-induced fluorescence enhancement of the protein when the fraction of HMM "affinity"-labeled by vanadate plus ADP was varied. The analysis is based on a prediction that these two changes should be proportional to each other if myosin consists of a single kind of active site and generates the rate-limiting myosin**product complex emitting enhanced fluorescence. Although the difference between these two changes was very small with native HMM, it was large with HMM in which 5 fast-reactive sulfhydryl-groups per head were pre-modified with thimerosal. The difference indicated the existence of heterogeneous active sites in the SH-modified HMM. The results were best explained in terms of the hypothesis that fifty percent of the active site splits MgATP by a mechanism giving a fluorescence enhancement whereas the other fifty percent splits MgATP by another mechanism giving no fluorescence enhancement. Two possible explanations for the existence of heterogeneous active sites in the SH-modified HMM are discussed. One assumes the pre-existence of some sort of 1:1 heterogeneity in the micro-environment of the active sites and the other, which is considered less likely, assumes the introduction of the heterogeneity as a result of the SH-modification.     

Transformation of arachidonic acid into thromboxane B2 by the homogenates of activated macrophages

The homogenates of activated macrophages obtained from liquid paraffin-injected guinea pig peritoneum were incubated with [14C]arachidonic acid or with radioactive prostaglandin endoperoside [14C]prostaglandin H2. The major radioactive metabolite in both cases was thromboxane B2, which was identified by NaBH4 reduction, rechromatography and autoradiography.