Histochemistry最新文献

In this report the occurrence of mammosomatotroph (MS) cells was correlated with changes in the somatotroph population of adult rat pituitary gland submitted to various experimental conditions (ovariectomized, orchidectomized and intact males, and after treatment with oestradiol benzoate). Cell and volume density of somatotrophs were assessed in sections stained with the immunogold-silver enhancement technique. Mammosomatotrophs were identified by double immunogold labelling at the electron microscopic level. Colocalization of prolactin (PRL) and growth hormone (GH) in the same cell was rarely observed. Only a few MS cells (0.1-0.2% of all parenchymal cells) were found in some experimental models. Oestrogen treatment decreased both cell and volume density of somatotrophs in ovariectomized rats. In this model, serum GH increased significantly but no changes in the pituitary content of the hormone were observed. Our results demonstrate that MS cells are an uncommon cell type in the pituitary of adult ovariectomized, orchidectomized and intact male rats. The oestrogen treatment, which is well known to induce proliferation of lactotrophs, has no effects on the MS population. Data presented in this report do not support the suggested role for mammosomatotrophs as transitional cells in the presumptive interconversion of PRL and GH producing cells.

Recent studies in fetal lung using immunological and molecular probes have revealed type I and type II cell phenotypic markers in primordial lung epithelial cells prior to the morphogenesis of these cell types. We have recently developed monoclonal antibodies specific for adult type I cells. To evaluate further the temporal appearance of the type I cell phenotype during alveolar epithelial cell ontogeny, we analyzed fetal lung development using one of our monoclonal antibodies (mAb VIII B2). The epitope recognized by mAb VIII B2 first appears in the canalicular stage of fetal lung development, at approx. embryonic day 19 (E19), in occasional, faintly stained tubules. Staining with this type I cell probe becomes more intense and more widespread with increasing gestational age, during which time the pattern of staining changes. Initially, all cells of the distal epithelial tubules are uniformly labelled along their apical and basolateral surfaces. As morphological differentiation of the alveolar epithelium proceeds, type I cell immunoreactivity appears to become restricted to the apical surface of the primitive type I cells in a pattern approaching that seen in the mature lung. We concurrently analyzed developing fetal lung with an antiserum to surfactant apoprotein-A (alpha-SP-A). Consistent with the findings of others, labeling of SP-A was first detectable in scattered cuboidal cells at E18. Careful examination of the double-labeled specimens suggested that some cells were reactive with both the VIII B2 and SP-A antibodies, particularly at E20. Confocal microscopic analysis of such sections from E20 lung confirmed this impression. Three populations of cells were detected: cells labeled only with alpha-SP-A, cells labeled only with mAb VIII B2, and a smaller subset of cells labeled by both.(ABSTRACT TRUNCATED AT 250 WORDS)

The characteristics of a monoclonal antibody produced against osteoclast-like multinucleated cells (MNCs) formed in rat bone marrow cultures were examined immunohistochemically and biochemically. The in vitro immunization was performed using as immunogen the MNCs from rat bone marrow cell culture, which revealed many characteristics of osteoclasts. After screening and cloning of hybridomas, the monoclonal antibody HOK 1 was obtained. This antibody reacted weakly with stromal cells and intensely with both MNCs and their putative migratory traces on culture dishes. Immunofluorescent examination of paraffin sections revealed intense reactivity on the epithelium of the choroid plexus, the ileum and the proximal-convoluted tubules of the kidney, and also on bone cells such as osteocytes, osteoblasts, and osteoclasts. Western blotting using purified rat osteopontin verified that the antigen recognized by HOK 1 was osteopontin. Positive HOK 1 immunoreactivity was further observed in the resorption lacunae formed by a culture of MNCs on human tooth slices and on the surface of osteoclasts. The present data suggested that osteopontin is preferentially present on the resorption lacunae in resorbing calcified matrices and that osteoclasts under a specific state might trap this protein on their cell surface.

Numerous events in the cell, such as gene expression, cell growth and metabolism are regulated by signal transduction pathways involving protein kinase C (PKC). Recent data indicate that a PKC-dependent mechanism also underlies the apoptotic death of cells induced by glucocorticoid hormones. In this report we have analysed the changes of PKC during dexamethasone-induced apoptosis in thymocytes by means of immunocytochemical and immunochemical analysis. The data obtained show an increase and intracellular movement of protein kinase C, which is translocated to the nucleus and linked to the nuclear matrix during the apoptotic process.

The expression of intercellular adhesion molecule-1 (ICAM-1) was studied in 8-week-old non-obese diabetic (NOD) mice and low-dose streptozocin-treated (LDS) mice. ICAM-1 expression in NOD mice was observed at the islet periphery, corresponding to the peri-islet venular network, within the islet and on scattered elements along septa of the exocrine portion of the pancreas. Image analysis demonstrated that LDS-treated animals had less ICAM-1 immunoreactivity within and around the islets compared to NOD mice. At the ultrastructural level the peri-islet vessels were found to be filled with mononuclear elements. Moreover, endothelial cells showed signs of activation, and margination of monocytes and polymorphonuclear leukocytes was observed.

Carbonic anhydrase (CA) activity was localized in the salivery glands of the cockroach, Periplaneta americana, by (1) Hansson's histochemical technique, and (2) the use of the fluorescent sulphonamide, 5-dimethyl-amino-naphthalene-1-sulphonamide (DNSA). Both techniques reveal the same distribution pattern of CA in the four morphologically different cell types of the glands: peripheral cells, central cells, inner acinar duct cells, and distal duct cells. Positive reactions with Hansson's cobalt/phosphate technique were found in the apical regions of the peripheral cells and the distal duct cells, and were inhibited by 10(-5) M acetazolamide in control experiments. No staining could be detected in the central cells and the inner acinar duct cells. The fluorescent CA inhibitor DNSA (10(-4)M) specifically stained the peripheral cells and the distal duct cells in methanol-fixed cryostat sections, whereas the central cells and the inner acinar duct cells remained unstained. The role of CA in the peripheral cells is not clear. CA activity in the distal duct cells may provide the protons needed to run the vacuolar-type H(+)-ATPase on the apical infoldings of the cells. This ATPase may be involved in modification of the primary saliva.

In situ hybridization (ISH) at the electron microscopic level is essential for elucidating the intracellular distribution and role of mRNA in protein synthesis. We describe our electron microscopic ISH method using biotinylated oligonucleotide probes for rat growth hormone and prolactin mRNAs and compare the preembedding method with the postembedding method. Preembedding electron microscopic ISH localized rat growth hormone and prolactin mRNAs on the polysomes of the rough endoplasmic reticulum (RER). Rat growth hormone mRNA was distributed diffusely on the RER, whereas rat prolactin mRNA was scattered and distributed focally. Thus there might be a specific translational site for prolactin mRNA on the RER. Rat growth hormone mRNA signals were also recognized on the polysomes of the RER, using the postembedding method with streptavidin gold conjugate. The hybridization signal intensity using the postembedding method was lower, and non-specific signals were more frequent, in comparison with the preembedding method. The preembedding method thus appears to be easier and better than the postembedding method from the viewpoint of utility and preservation of mRNA. Electron microscopic ISH is considered to be an important tool for evaluating the intracellular localization of mRNA and the site of specific hormone synthesis on the RER.

The study was aimed at a morphological demonstration of calcitonin (CT) gene expression in cultured TT cells, or, more specifically, hybridocytochemical detection of CT mRNA and calcitonin gene-related peptide (CGRP) mRNA and ultrastructural localization of the two hormones. The TT cells originated from medullary carcinoma of human thyroid gland. Ultrastructural studies of TT cells demonstrated a well-developed rough endoplasmic reticulum, large Golgi apparatus and low number of secretory granules. Hybridocytochemical studies showed the presence of mRNAs for CT and CGRP in all TT cells. At the ultrastructural level, double immunolabelling demonstrated that the two hormones were always expressed together in the same secretory granules. Our results provide a significant addition to the biochemical studies performed up to now and indicate that all TT cells produce both mRNAs and both hormones in parallel.

The aim of the present study was to map immunohistochemically the distribution of the glucocorticoid receptor (GR) in rat skin. Nuclear GR-like immunoreactivity (LI) was found in both epidermis and dermis. In the epidermis, the basal cell layer showed an intense immunoreaction; the lower part of the spinous layer was also labelled. In the dermis, the fibroblasts as well as the sweat glands, sebocytes and adipocytes were GR-immunoreactive (IR). In the root sheath of the hair follicle the staining was most intensive in the outer layer. The endothelial cells comprising the smooth muscle cells of the blood vessels, as well as the arrector pili muscle, showed GR-LI. In the peripheral nerves, the immunoreaction was localized to the nuclei of the Schwann cells and in the perineurial fibroblasts. Mast cells did not show nuclear GR-LI. Based on our immunocytochemical findings that several cell types of the skin are GR-IR, the variable physiological and pharmacological effects of glucocorticoids are easier to understand.

The subpopulations were compared of neurons in human dorsal root ganglia (DRG), as substance P, identified by somatostatin, Glycine max lectin (SBA) specific to terminal N-acetylgalactosamine, and Ulex europaeus I agglutinin (UEA-I) specific to L-fucose. The lectins and neuropeptides all bound to neurons of small diameter. Furthermore, the majority of the SBA binding neurons or somatostatin positive neurons were also UEA-I binding neurons. However, SBA binding neurons were not colocalized with somatostatin or substance P. Less than 20% of substance P positive neurons showed colocalization with L-fucosyl residues, and approximately 10% of L-fucosyl residues showed colocalization with substance P. Our results suggest that both L-fucose and terminal N-acetylgalactosamine containing neurons in the human DRG are subjected to different subpopulations from substance P or somatostatin positive neurons.