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Dental enamel exhibits a highly mineralised structure and contains not only mineral substances but also organic components. The fine organic elements in the enamel cannot be detected by clinical examinations and most frequently are recognised by in vitro studies. The aim of the present study was to assess selected organic elements of enamel: lamellae, tufts, spindles, bulbs and spheroids and to appraise the suitability of permanent bovine teeth as substitutes of permanent human teeth in dental studies. Examinations were performed on 205 permanent bovine teeth obtained from healthy 2.5- to 4.5-year-old individuals (of black-white lowland race). Tooth sections were obtained by cutting crowns, using a slow revolving diamond disc saw, cooled with distilled water. Following preliminary appraisal and within 24 hours, the sections were stained with various techniques, including azane, picric acid, hematoxylin + picric acid, hematoxylin, eosin, fuchsin, H+E according to Mallory and were then analysed under a Nikon Optiphot-2 light microscope. Variable distributions of the evaluated organic elements of enamel were noted but most of them were located in the projection of smooth surfaces, compared to their location in the projections of incisal margins or masticator surfaces in bovine teeth. Bovine permanent frontal teeth may provide a substitute for human teeth but bovine lateral teeth, however, seem to be of limited use in dental studies.
The aim of the study was to investigate the presence, localisation and function of brain nitric oxide synthase (bNOS) in the male genital accessory glands of rats in the course of their postnatal development. Localisation of the bNOS was immunocytochemically investigated in the epididymis, seminal vesicle and ventral prostate of male Wistar strain rats at 1, 5, 10, 20, 28, 35, 45 and 59 days of age. The method employed involved mouse monoclonal antibodies against rat bNOS in combination with tyramide signal amplification (CSA). The intensity of the reaction in the organs studied was determined using computer software to demonstrate the optical density of the reaction product obtained. In the epididymis a weak reaction was observed in the connective tissue/muscular sublayer on the 28th and 45th days of life. In the seminal vesicle and ventral prostate a positive reaction appeared in the epinuclear portions of glandular epithelial cells on the 20th day of life, reaching a maximum intensity on the 28th day and thus before the rats reached maturity. The results obtained allow the conclusion to be drawn that nitric oxide resulting from bNOS-activity participates in the processes of differentiation and of function in the epididymis, seminal vesicle and ventral prostate.
The study aimed at determining effects of monosodium glutamate (MSG), introduced in the perinatal period, on the reproductive system of .sexually mature female rats. ln days 2, 4, 6, 8, l0 the: newborns received s.c. injections of MSG (4 mg/g body weight) or2% NaCl solution. When the animals reached the age of 6, l2 or l8 months, their ovaries and uteri were isolated for histological and morphometric studies while in their sera estradiol level was estimated by the RIA technique. The perinatal injection of MSG was found to decrease relative weights of ovaries and uteri. In the ovaries increased numbers of primordial follicles and deceased numbers of graafian follicles were detected . Also the thickness of endometrium and of the epithelium, which lined the endometrium, were lowered in females, which received perinatal injections of MSG, as compared to the controls. Serum estradiol level in MSG injected females was lowered at the age of 12 and 18 month old females the alterations were accompanied by obesity and a decreased body length.
Computer-assisted analysis of histologic images of rat testis in the course of postnatal period demonstrated its stepwise development. Three stages of the development could be distinguished, associated with different number of Leydig cells and with distinct secretive activity of the cell, as reflected by serum testosterone levels.
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