The epithelial changes observed during hamster cheek pouch-DMBA carcinogenesis were classified as hyperplasia, dysplasia and carcinoma stages; carcinomas were usually well differentiated. During carcinogenesis, epithelial thickness increased and in dysplasia and carcinoma stages superficial cells exhibited a marked shift from ortho- to parakeratinization. Marked changes in intercellular organelles were observed and intracellular spaces increased progressively in size. Desmosomes were less commonly seen during carcinogenesis whereas the frequency of gap junctions appeared to increase. The epithelial-connective tissue junction exhibited prominent changes with increasing irregularity, discontinuity and duplication of the lamina densa and a decreasing frequency of hemidesmosomes. Cytoplasmic processes, some containing lysosomal dense bodies, often passed through breaks in the lamina densa and extended into a relatively structureless connective tissue. The results are discussed in relation to the changes in cellular organelles occurring in abnormal epithelial differentiation mediated by the carcinogen and to possible factors which might be involved in the process of cellular invasion.

9,10-Dimethyl-1,2-benzanthracene↗

PubMedDate not supplied

Leptospira interrogans serovars hardjo and pomona: causes of infections in dairy cows and humans in Florida.

Leptospirosis was diagnosed in 11 milkers on 3 dairy farms in a Florida county. Serologic test results identified Leptospira interrogans serovar hardjo as the infecting organism in milkers and cows on one farm, and hardjo was isolated from two cows. On the second farm, serovars hardjo and pomona were implicated serologically in the cows and milkers, and pomona was isolated from two milkers. On the third farm, hardjo infection was identified by serologic tests in one milker, and hardjo was isolated from another.This was the first isolation of hardjo from a human being reported in the United States. Leptospiral infection is an occupational hazard for dairy milkers in some areas of the United States. Thus, the authors recommend that preventive measures should be taken. These measures should include boots and other protective clothing and protection from urine spray for the eyes and nose.

Adolescent↗