Archives d'anatomie microscopique et de morphologie experimentale最新文献

Hypercalcemia was induced in Clarias batrachus by treating them with vitamin D3 (5,000 I.U./100 g body wt.) and/or 0.5% solution of CaCl2. The animals were killed on 1st, 3rd, 5th, 9th, 13th and 17th days after the initiation of the experiment. Histological preparations of the ultimobranchial gland (UBG) were made. The gland exhibits nuclear hypertrophy, hyperplasia and loss of staining response corresponding to the rise in serum calcium levels. At later intervals, the UBG shows exhaustion and degeneration which is evident from vacuolization and nuclear shrinkage of the ultimobranchial cells after day 13 in groups B and C and day 9 in group D.

Cat mandibular symphysis was investigated with histological methods in animals of ages between 3 weeks of intra-uterine life and 56 days post-natal. As in rodents, carnivores and insectivores, Meckel's cartilages fuse in the midline and form a cartilaginous nodule which persists in the symphysis until birth. This nodule, which we have called the symphyseal Meckelian islet, is isolated from Meckel's cartilage, of which only very small calcified islets are left as intramandibular traces after endochondral ossification. Both hemimandibles are bordered by secondary cartilage, which undergoes endochondral ossification, and by chondroid tissue, which is less abundant than in man. At birth, secondary cartilage of both hemimandibles forms a synchondrosis, the lingual part of which undergoes gradual resorption in the 4-week-old cat. The vestibular part is still present at 8 weeks.

Tamoxifen or 4-hydroxytamoxifen were injected either alone or in combination with oestradiol into 4-5 day-old chick embryos in order to study their action on the sex differentiation of the gonads. The results of the histological study of the gonads performed at the stage of 16-19 days warrant the following conclusions: None of both anti-oestrogens exerts an effect on the testes. None of both compounds modifies the sex differentiation of the female gonads. Tamoxifen exerts an antagonistic action on the feminization of the testes by oestradiol. These conclusions do not lend support to the hypothesis according to which oestrogens play a role in normal sex differentiation of the female gonads.

The cytotoxic properties of purified antibodies reacting specifically with an antigen of the proximal secretory tubule cells have been studied. Intravenous injections of these antibody preparations together with complement (Guinea pig serum) into 2-3,5 day old or 12-13 day old chick embryos do not interfere with the development of either the meso-or metanephros. Furthermore, when suspensions of live metanephric cells treated first with anti-proximal segment antibodies and second with complement are cultured under organotypic conditions, one observes the reconstitution of all the characteristic segments (proximal, intermediate, distal and collecting) of the urinary tubule. It appears therefore that, in vivo as well as in vitro, these antibody preparations do not exert any cytolytic activity although it can be demonstrated that, at least under in vitro conditions, they bind to the surface of the proximal secretory cells and that the antibody-sensitised cells fix complement.

The histopathological status and histologically demonstratable succinate dehydrogenase activity were evaluated on contiguous heart sections of rats fed low erucic acid rapeseed oil for 18 weeks. The histologically demonstratable SDH activity was quantified and could be related with the severity of the lesion at the same location. These results were discussed in terms of effects of dietary fat on mitochondria.

Studies were made to compare the impact of immersion fixations with different concentrations of paraformaldehyde (10%, 6% + 0,25% glutaraldehyde, 4% and 1%) on the cellular and subcellular structure preservation. The study was performed on 3 animals. Similar conditions existed for all the preparative steps, since they were done in one operation. Cellular parameters as the volume densities of hepatocytes (VVH), nuclei (VVNH), cytoplasm (VVCYT) and extra-hepatocytic space (VVEX) were assessed by light microscopy on toluidine blue stained semi-thin sections at X 1 000. The volume (VVM), the surface density of mitochondria (SVMO) and their mean profile size (am) were measured at the electron microscopic level (X 15 000). The most striking differences were observed in the volume density (VVM), surface to volume ratio (SV) and mean profile area of the mitochondria (am). Qualitative results revealed that the zone of good electron microscopic observation varied according to the concentrations of the fixative. In conclusion, the best qualitative and quantitative preservation is assumed with 4% paraformaldehyde and at a less degree with 6% paraformaldehyde + 0,25% glutaraldehyde.

Previous studies performed on different species have shown that these cells could be recognized by their morphologic and immuno-histological features. In early stages, these cells are able to take up and decarboxylate amine precursors. Therefore the aim of the present work was to determine if this uptake could be correlated with ultrastructural modifications. A processing technique allowing amine detection and correlative ultrastructural examination was used. Rabbit foetuses 13, 14, 17 and 21 day old were studied. The gastro-intestinal tracts of L-DOPA treated or untreated foetuses were removed in a glutaraldehyde-formaldehyde mixture and embedded in epoxy-resin. Semi-thin sections allowed to locate fluorescent cells in U.V light microscopy; adjacent thin sections were observed in electron microscopy. The first green fluorescent cells appeared in the 13 day old foetuses treated with L-DOPA. By this stage, these cells were very scarce and appeared poorly differentiated in electron microscopy. Between the 15th and the 18th day, the green fluorescent cells contained only small round granules. By the day 19, orange-yellow cells can be observed in L-DOPA treated and untreated foetuses. These cells possessed characteristic enterochromaffin granules. The green fluorescent cells of 21 day old foetuses, treated with L-DOPA, exhibited various fluorescence intensities correlated with the heterogeneity of the secretory granules. Some foetuses of each stage were treated with Falck's technique. This method gave similar results concerning the chronology of fluorescent cell detection.

The crooked neck dwarfism (cn/cn) is characterized, among other anomalies, by a muscular hypoplasia, particularly conspicuous in the tibiotarsal segment. Histological observations were performed between day 6 and day 12.5 of incubation. They show, in the tibiotarsal segment, that the hereditary muscular hypoplasia is not caused by a defect of the normal muscular splitting pattern. Indeed, in the mutant, the splitting of muscle masses proceeds normally up to the last partition (day 7-7.5), but is followed by the secondary fusion of individuated muscles into an unpatterned muscle tissue. Thus the mutant phenotype is the result of an inability of the muscle pattern to become stabilized into definitive structures.

The study of the embryonic origin of the striated satellite cells is based 1) on a comparison of the specific morphology of the nuclei in satellite cells and in myofibers, in late embryonic and postnatal chick and quail muscles; 2) on a species-identification of the satellite cell nuclei in hetero-specific muscle tissues where myofibers derive from implanted quail somite and connective tissue fibroblasts from the chick host somatopleura. Observations clearly demonstrate that myofibers and satellite cells are of the same somitic origin. It is concluded that satellite cells represent a portion of the myogenic cell lineage.

Syncytiotrophoblast from human term placenta, studied by stereological methods both by light and electron microscopy, was shown to account for 19.49% of the placenta volume. Significant differences in volume density were observed in syncytiotrophoblast from villi obtained from different regions of the cotyledon. These differences may be caused by the heterogeneous conditions of oxygenation in the intervillous space blood and its effect on trophoblastic growth. The volume density of the organelles, related to syncytioplasm volume, was 0.0524, 0.0122, 0.0033 and 0.1136, for mitochondria, lysosomes, Golgi complex and endoplasmic reticulum, respectively. There were no differences in the volume densities of the different organelles among the four cotyledonary regions studied.