Analysis of silver binding nucleolar organizer regions in exfoliative cytology smears of potentially malignant and malignant oral lesions

Nucleolar organizer regions are nucleolar components that contain proteins that are stained selectively by silver methods; they can be identified as black dots throughout the nucleolus and are known as silver binding nucleolar organizer regions (AgNOR). The number of AgNOR is related to the cell cycle and the proliferative activity of the cells. We investigated AgNOR using exfoliative cytology smears of potentially malignant oral lesions. Eighty individuals were divided into four equal groups: healthy controls, oral leukoplakia, oral submucous fibrosis and oral squamous cell carcinoma. The mean number of AgNOR in each study group gradually increased from control to oral leukoplakia to oral submucous fibrosis to oral squamous cell carcinoma. The proliferative index was increased in the oral premalignant and malignant patients compared to normal subjects. The mean AgNOR size gradually increased from control to oral leukoplakia to oral submucous fibrosis to oral squamous cell carcinoma. Spherical shaped AgNOR were most common in controls, whereas large, clustered and kidney shapes were most common in oral squamous cell carcinoma. Multiparameter analysis of AgNOR in oral exfoliative smears is a simple, sensitive and cost-effective method for differentiating premalignant from malignant lesions and can be used in conjunction with routine cytomorphological evaluation.     

The immunological properties of the main outer membrane protein of Legionella

The immunogenic properties of Legionella outer membrane main protein (OMMP) were studied by its effect on the proliferative activity of lymphocytes in guinea pigs. Preliminary immunization with OMMP activated only the specific and nonspecific proliferation of spleen cells. After infection with Legionella, secondary immune response developed in the spleen and lungs of previously immunized animals, in contrast to intact ones, and the nonspecific proliferative activity of lymphocytes in the spleen and lungs of previously immunized animals considerably increased. These results are indicative of the fact that Legionella OMMP, similarly to other Legionella antigens and immunomodulators, may be used for the formation of protective immunity.     

Site of fidget gene action and its interaction with the ocular retardation gene in cultured mouse embryo retinas

The eye rudiments of 10 and 11 days old mouse embryos of the genotypes +/+ +/+, fi/fi +/+, +/+ or/or, fi/fi or/or and 11 days old embryos of the genotype fi/+ or/+ were cultivated in vitro during 24, 48 and 72 hrs. The expression of the fi gene was shown in the cells of the cultivated fi/fi +/+ retina: its proliferative activity was inhibited. The fi gene was not active in the cells of the developing lens and the anomalies of the latter in homozygotes arose secondarily, due to the inhibition of growth of the retinal rudiment. The fi and or genes interacted synergically in the cultivated fi/fi or/or retina, thus resulting in the marked inhibition of its mitotic activity. This suggests that both the genes act in the retinal cells and, apparently, affect different links of the biochemical chain of events in the preparation of DNA replication.     

Cell differentiation of the head ectoderm in mouse embryos in vitro

Cell differentiation has been studied in the explants of head ectoderm of 8, 9 and 10 day old mouse (CBA) embryos and of head epidermis of 13 day old embryos. Pieces of ectoderm were taken from the temporal region. It was established by indirect immunofluorescence that within 10, 15 and 20 days of cultivation spheroids with keratins or crystallins in some groups of fibres formed in the head ectoderm explants from 9 and 10 day old embryos. When cultivating the regions of head epidermis from 13 day old embryos, spheroids formed with keratin only in their cells. The data obtained suggest that there appear to be two clones of cells determined to the synthesis of keratins or crystallins in the head ectoderm of early mouse embryos. During embryogenesis, the number of cells determined to the synthesis of keratins appears to increase in the regions not related to the eye area. At the same time, the clone of cells determined to the synthesis of crystallins appears to be eliminated.