The present study was undertaken to investigate the changes in composition of the mammary gland volume unit through all phases of lactation in rats subjected to lead acetate administration via drinking water during the first pregnancy and lactation. Stereological analysis was performed on serial slices of the organs. The point of support for our study was the fact that lead, apart from being a poison of wide range, is mostly poisonous for gonads and to their supervisory neuroendocrine structures and the mammary gland, in morpho-functional sense, should be admitted as their integral part. On the 7th day of lactation there was significant difference of the alveolar and ductal epithelium phase, which was significantly reduced in animals treated by lead. In the same animals there were larger lumens of the alveoli and ducti, more abundant connective tissue and greater number of the adipocytes but these differences in comparison to control group were not significant. On the 14th day of lactation there was significantly greater presence of the adipocytes phase and stromal tissue while the volume of the epithelium of alveoli and ducti was significantly reduced in study group. There was also an increase of the alveoloductal lumen phase but this was not significant. On the 21st day of lactation there were significant difference in epithelial and stromal tissue phases in two groups, having a significant decrease in the epithelium, and significant increase of stromal tissue in glands of lactating rats treated by lead acetate. There were non-significant differences as far as the presence of the adipocytes and alveoloductal lumen volume were concerned although the values for both phases in study group were above the control values. On the basis of given results we concluded that lead changes the quantitative characteristics of the mammary gland, i.e. the composition of the volume unit of the organ through all phases of lactation.

This is an immunohistochemical study of the local cellular immune response characteristic in inflammatory-regenerative and dysplastic flat colonic mucosa. The aim of this study is to determine a possible existence of the mononuclear cellular infiltration specificity which could be important for the prognosis in further development of dysplastic lesion. Biopsy specimens from 170 patients (specimens stained by hematoxylin eosin) were examined. 74 specimens showed inflammatory-regenerative changes and 96 had dysplastic changes (38 with mild dys-plasia, 28 with moderate dysplasia and 30 with severe dysplasia). Three monoclonal antibodies were used for the identification of mononuclear cells in the inflammatory cellular infiltration in the lamina propria of colonic mucosa. The inflammatory cells type and their location in respect of the epithelial cells and lesion itself were analysed and their number was determined by the semi-quantitative method. T lymphocytes were the dominant cells of local immune response in dysplastic lesions while macrophages were less present and B lymphocytes, as rare cells, were present in sporadic cases. It is notified that increase in the extent of dysplasia was followed by increase in the number of macrophages and T lymphocytes in particular. Immediate contact between macrophages and T lymphocytes in epithelial dysplasia was found in a small number of cases and was mostly independent from the intensity of dysplasia. Signs of the direct lytical effect of the mononuclear ceils on dysplastic epithelial cells were not observed in this contact. It seems that epithelial dysplasia does not provoke more significant local immune response which is the most probably a part of the chronic non-specific inflammation that has a negative influence on further development of the lesion. The conclusion is that local immune response in the dysplastic alteration of flat colonic mucosa has no importance in further prognosis of the lesion.