Ultrastructural and biochemical studies have suggested that bronchopulmonary carcinoids and oat cell carcinomas may be derivatives of neuroendocrine cells; their amine and/or peptide secretory ...capabilities may at times be reflected in clinical hormonal syndromes. This investigation was prompted by the hypothesis that dysplastic neuroendocrine bronchial cells may also exhibit structural and functional aberrations of their secretory apparatus. Surgical specimen samples from 5 human dysplastic bronchi were studied ultrastructurally; 7 normal bronchi served as controls. Golgi complexes of dysplastic cells were distinctly less prominent than those of the controls. Moreover, the Golgi vesicles of dysplastic cells appeared significantly smaller than their counterparts in normal cells (P less than 0.01). Also, dysplastic neuroendocrine cells displayed significantly fewer secretory granules per cell than the controls (P less than 0.05). These findings indicate structural abnormalities in the secretory apparatus of neuroendocrine cells in dysplastic bronchi and correlate with experimental observations of aberrant hormonal production associated with bronchial dysplasia. Thus, the possibility arises that bronchial epithelial dysplasias may be detected and monitored through laboratory determinations of their secretory products.
The ultrastructural appearance of viruslike particles in several malaria parasites at different times in sporogony is described in detail. Emphasis is placed on particle size, 42 to 52 nm, density ...and the presence or absence of a geometric configuration of particle aggregations in P. berghei ookinetes, and P. gallinaceum early oocysts. This particle appearance is compared with that noted in later oocysts of P. berghei, P. gallinaceum, and P. c. bastianelli and with negatively-stained particles obtained by fractionation of A. stephensi mosquito midguts heavily infected by P. berghei oocysts. Although particles are dispersed in later oocysts, particle size and shape is similar to that noted in the aggregates found in early forms. Aggregations of particles in a geometric configuration in ookinetes and early oocysts is associated with a particle of smaller diameter and the absence of a limiting membrane or envelope. This suggests an incomplete or nascent virus particle form. The observations of such particles in malaria and other blood parasites is compared with the present findings.
