Functional and developmental morphology最新文献

The involution of Wolffian duct in female rat fetuses from 15 to 21 days of gestation was studied in electron microscope. The female Wolffian duct stopped its differentiation on day 17 and the onset of duct regression was found in 18 days old fetuses. The involution was accompanied by degeneration and disintegration of epithelial cells, removal of basal lamina and elimination of altered cells into periductal mesenchyme. Although the mechanism of programmed cell death contributed to the WD regression the findings of non-altered epithelial cells supported the opinion of possible migration of some WD cells into the mesenchymal cell compartment.

In this work the author examined the histological and submicroscopical picture of the seminiferous parenchyma in 5 breeding rams from a herd in which intoxication with copper oxide from industrial emissions of a copper producing plant had been diagnosed. The toxic effect irreversibly damages all developmental stages of the germ cells. It injures the cell membranes of both germ cells and Sertoli cells. Similar changes were observed on the interstitial cells. The degree of injury to the germinative epithelium confirms its significant role in the decreased reproduction rate of the herd under examination.

C6 glioma cell suspension has been inoculated into the brain of adult Long Evans rats. Animals were allowed to survive 2 to 60 days and then immunohistochemical detection of S100 protein and glial fibrillary acidic protein (GFAP) in tumors was carried out on paraffin-embedded sections. In our in vivo model the maximum positivity for both S 100 protein and GFAP was observed in C6 glial cells at 10 days after implantation. At that time increased levels of S 100 protein were expressed both in central areas containing more differentiated C6 glioma cells and in host reactive astrocytes at tumor boundary. Almost no S 100 protein was found in dividing and invading, i.e. less differentiated, C6 glioma cells at tumor periphery and in perivascular spaces of adjacent blood vessels. The distribution of GFAP positive cells followed a similar pattern as that of S 100 protein containing C6 cells. GFAP expressing cells were revealed in quiescent central tumor portions which were occupied by more differentiated cells. Tumors were surrounded by strongly GFAP positive host reactive astrocytes. Later on, when signs of tumor regression appeared there was a decrease in S 100 protein and GFAP immunoreactivity of C6 glioma cells. To summarize, we developed an in vivo model for observation of cell differentiation within a growing glioma. Less differentiated and more malignant glioma cells expressed almost no S 100 protein and GFAP in contradistinction to central and more quiescent tumor portions.

The purpose of the present study was to describe geometry of branching, topography and sources of blood vessels supplying the mesonephros of three different species of amphibia and to infere from the results their common and species-specific features. The detailed information on arrangement of portal and arterial blood supply to mesonephros is necessary for better understanding of the conditions under which these kidneys function. For this reason the blood vessels of the mesonephros of adult Hynobius Keyserlingi, Triturus vulgaris and Rana temporaria were injected with stained gelatin. The urodelian kidneys were shown to be supplied by numerous segmental arteries. Three types of arterial supply to glomeruli were distinguished: those mediated by short, medium and long branches, which create different physical conditions for the glomerular filtration in pertinent nephrons--as the blood pressure necessarily decreases with the increasing distance from the aorta. The tributaries to the renal portal vein were identified in all three species as the veins draining hind limbs, tail, pelvis and body wall. It is being suggested that the purpose of this large drainage area is to secure a sufficient volume of blood to the peritubular network.

The horns of bicornic uterus in the rat develop from the middle parts of Müllerian ducts. Female rat fetuses for this study were taken on 16-21 days of gestation. On the 16th prenatal day the uterine part of Müllerian duct was short, lined with a columnar epithelium and basal lamina around the duct was incomplete. During further development the duct enlarged, epithelial cells became taller and basement membrane was formed. Until birth the epithelium remained relatively indifferent as far as the periductal mesenchyme. Contrary to the animals with a long gestational period and human, the differentiation of uterine wall including uterine mucosa in the rat takes place after birth.

The nucleolar test was used for evaluation of the rRNA biosynthesis in two populations of chick embryonic cells. In chick embryos, practically 100 per cent of proerythroblasts (starting from embryonic day 3) as well as hepatocytes (starting with embryonic day 5) synthetized nucleolar, i.e. ribosomal RNA. In consequence of a single administration of the well known teratogens--actinomycin D, cyclophosphamide or hydrocortisone--the percentage of rRNA synthetizing proerythroblasts and hepatocytes decreased characteristically--in dependence on the teratogenic drug. The presented method can be employed when toxicity of drugs or other chemical compounds is evaluated in cell populations possessing high metabolic and proliferative activity.

Basic morphometric parameters of melanosomes isolated from mouse hair, hamster eye and hamster hair are given and tabelized with those published formerly to enlarge the widest published collection of melanosomes isolated from different types of pigmented tissues up to 17 types. The splitting of melanosomes isolated from mixed tissue of hamster eyes into two subpopulations confirmed the presence of double origin of melanosomes in the eye. The close correspondence of subpopulations of hamster eye melanosomes with hamster hair and hamster melanoma (type Bomirski) respectively supports the hypothesis of high structural stability of melanosomes even under pathological conditions.

The present study describes a well developed rete ovarii in the ovary of the adult Indian vespertilionid bat, Scotophilus heathi, and supports the role of the rete system in early follicular growth in the ovary. A close contacts between the rete tubules and follicles have been found at the beginning of the follicular growth in the mature ovary. Ultrastructural features of connecting rete cells indicate the active protein synthesis, while those of intraovarian rete cells suggest their role in transportation of secretory materials.