J. Althoff

Oral leukoplakia : a scanning electron microscopic study of epithelial surface patterns

Biopsies from oral leukoplakias of different anatomic locations were studied by light- and scanning electron microscopy. Clinically, 11 cases showed the homogenous, flat type, and 3 represented the inhomogenous, nodular type of oral leukoplakia. The surface patterns of lining epithelial cells, as well as the cut surface structures were compared with those obtained by light microscopy. The results were compared with other published findings of normal oral mucosa, oral leukoplakia, oral carcinoma, and lesions of the uterine cervical mucosa. The epithelial surface cells revealed micropatterns comparable to normal ortho- or parakeratotic cells in the cases of homogenous oral leukoplakia. Biopsies showing varying degrees of dysplasia revealed cell surfaces with irregular microvilli or swollen microridges; cell forms also showed varying profiles and shapes as well as pleomorphism. Cell desquamation was seen in all cases. Since cell maturation and differentiation is linked to a specific surface morphology, SEM has to be considered as a further valuable diagnostic method.

A chronic study of praziquantel in syrian golden hamsters and Sprague-Dawley rats

Groups of Syrian golden hamsters and Sprague-Dawley rats received 100 mg or 250 mg praziquantel/kg body weight, intragastrically by oral gavage once weekly for 80 weeks and 104 weeks, respectively. In both hamsters and rats the observed differences in tumour incidence, latency and multiplicity revealed no positive dose response effect. Tumours observed corresponded in their origin and morphology to those which develop spontaneously in these species. Haematological and clinico-chemical values were normal. Whereas the average survival time was slightly shortened in rats, female hamsters showed reduced weight gains in the high dose level groups, although water intake and food consumption were increased.

Study of biopsies from lesions of the oral mucosa by scanning electron microscopy (S.E.M.)

Surface epithelial cells from 55 biopsies including lichen planus, leukoplakia and squamous cell carcinoma were studied by scanning electron microscopy. The surface structures of the various oral lesions demonstrated morphological differences. After more information has been collected, the method of SEM may be of value for the recognition of pre- and early neoplastic lesions in the oral cavity.