The Histochemical Journal最新文献

The ability of tannic acid to enhance binding of glycosaminoglycans to purified collagen was analysed in an in vitro system using amino sugar analysis on an amino acid analyser, transmission electron microscopy, and scanning electron microscopy. Collagen was purified by digestion with trypsin, papain, and hyaluronidase. Purified collagen was incubated with hyaluronic acid or with chondroitin sulphate glycosaminoglycan and then treated with tannic acid. Tannic acid was found to enhance retention during preparation for electron microscopy of either of the glycosaminoglycans onto collagen fibres. The ability of tannic acid to enhance binding of collagen and glycosaminoglycans might explain, at least in part, its structural reinforcement effect on resected synovial joint-apposing surfaces during preparation for scanning electron microscopy.

An antiserum raised against a synthetic peptide derived from the primary amino sequence of rat secretogranin II (chromogranin C) was used for immunological (quantitative radioimmunoassay analysis) and immunohistochemical studies of normal human endocrine and nervous tissues. This antibody recognized a novel and biologically active neuropeptide which was coined as secretoneurin. In endocrine tissues, secretoneurin was mainly co-localized with chromogranin A and B with some exceptions (e.g., parathyroid gland). Secretoneurin was demonstrated immunohistochemically in the adrenal medulla, thyroid C cells, TSH- and FSH/LH-producing cells of the anterior pituitary, A and B cells of pancreatic islets, in endocrine cells of the gastrointestinal tract and the bronchial mucosa, and the prostate. Immunoreactivity determined by radioimmunoassay analysis revealed high secretoneurin levels in the anterior and posterior pituitary and lower levels in pancreatic and thyroid tissue. A strong secretoneurin immunoreactivity was also found in ganglion cells of the submucosal and myenteric plexus of the gastrointestinal tract, and in ganglionic cells of dorsal root ganglia, peripheral nerves, and ganglion cells of the adrenal medulla. Thus, secretoneurin may serve as a useful marker of gangliocytic/neuronal differentiation.

Glucose is actively absorbed in the intestine by the action of the Na(+)-dependent glucose transporter. Using an antibody against the rabbit intestinal Na(+)-dependent glucose transporter (SGLT1), we examined the localization of SGLT1 immunohistochemically along the rat digestive tract (oesophagus, stomach, duodenum, jejunum, ileum, colon and rectum). SGLT1 was detected in the small intestine (duodenum, jejunum and ileum), but not in the oesophagus, stomach, colon or rectum. SGLT1 was localized at the brush border of the absorptive epithelium cells in the small intestine. Electron microscopical examination showed that SGLT1 was localized at the apical plasma membrane of the absorptive epithelial cells. SGLT1 was not detected at the basolateral plasma membrane. Along the crypt-villus axis, all the absorptive epithelial cells in the villus were positive for SGLT1, whose amount increased from the bottom of the villus to its tip. On the other hand, cells in the crypts exhibited little or no staining for SGLT1. Goblet cells scattered throughout the intestinal epithelium were negative for SGLT1. These observations show that SGLT1 is specific to the apical plasma membrane of differentiated absorptive epithelial cells in the small intestine, and suggest that active uptake of glucose occur mainly in the absorptive epithelial cells in the small intestine.

A novel histoprocessing method for paraffin sections is presented in which the combination of vacuum and microwave exposure is the key element. By exploiting the decrease in boiling temperature under vacuum, the liquid molecules in the tissues have been successfully extracted and exchanged at relatively low temperatures during each of the steps from dehydration, clearing, and impregnation. In this vacuum-microwave method, an extremely short time suffices for the preparation of optimal-quality paraffin blocks. No xylene (but isopropanol instead) was used as the intermediate solvent. Thirty biopsies (thickness 2-4 mm) can be processed in 40 min. In addition, this approach can be used to produce large sections of giant blocks (4 x 6 x 1 cm3) which can be easily cut on a routine microtome due to the optimal paraffin impregnation. These giant blocks do not shrink during this vacuum-microwave histoprocessing.

The present immunohistochemical study revealed substance P-immunoreactive neuronal elements in the von Ebner's gland of rats. Immunoreactive ganglion cells were observed as single cells or groups of several immunoreactive ganglion cells among intra-lingual muscles, at the base of the vallate papillae and near the von Ebner's gland. Very numerous substance P-immunoreactive varicose nerve fibres ran closely associated with the serous cells and excretory duct cells, and were seen to run along blood vessels in the gland. Since substance P-immunoreactive ganglion cells were present near the glands, the immunoreactive varicose nerve fibres in the von Ebner's gland may be partly derived from the intra-lingual ganglion cells. These substance P-immunoreactive varicose nerve fibres may have an effect on the secretory activity of the serous cells and duct cells, and on the vasodilation of blood vessels of the von Ebner's gland. Actin immunoreactivity was seen in numerous myoepithelial cells embracing serous cells and duct cells, and in the smooth muscle cells of blood vessels of the gland. By using a double immunolabelling technique with anti-substance P and anti-actin sera, substance P-immunoreactive varicose nerve fibres were found to be in close contact with myoepithelial cells.

Bromodeoxyuridine (BrdUrd), a thymidine analogue incorporated into DNA, can be quantified by fluorescent or chromophoric quenching of dyes bound to DNA or with antibodies to BrdUrd. These technologies have been used since the 1970s as tools for measuring DNA synthesis in isolated chromosomes and in cells and tissues. This paper is Part I of a three-part comprehensive review of the literature over the last 20 years (to the end of 1993) describing the histochemical methods for measuring BrdUrd in cells and tissues. Fixation, denaturation and staining procedures are compared for quantifying BrdUrd for microscopy and flow cytometry. Non-immunochemical methods related to the quenching of fluorescent DNA stains by BrdUrd are also described. Methods are described for the comparative assay of cell kinetic parameters by tritiated thymidine and bromodeoxyuridine. The multivariate BrdUrd/DNA assay of Ts and Tc, and a comparison of recent methods based on the single biopsy bivariate analysis of Tpot, is presented. Recent developments in the use of double halopyrimidine label to determine kinetic parameters are also reviewed.

The populations of cells which produce immunoreactive growth hormone (GH) and thyroid stimulating hormone (TSH) in the rat pituitary gland do not occur in fixed percentages but vary greatly under different physiological and experimental conditions. These variations can be directly correlated to the levels of stimulation and/or inhibition of the specific secretory activity. In both types of cell, sustained stimulation with trophic hormones or blockage of the feedback mechanisms induces remarkable growth in the specific cell population. Conversely, the interruption or inhibition of the stimulus thwarted the hormonal secretion and caused a massive degeneration of redundant cells. The stimulation of both GH and TSH cells is accompanied by an enhanced secretory activity as judged by their higher concentrations in serum and hypertrophy of the cytoplasmic organelles involved in synthesis and intracellular processing of the hormones. By contrast, interruption of the stimulus is followed by a variable degree of disruption of the cytoplasmic organization, including a sizable degeneration of cells. In stimulated rats, the concentrations of both GH and TSH decreased significantly in pituitary tissue due to mobilization of the hormonal stores contained in secretory granules. On the other hand, the withdrawal of stimuli blocked the hormonal release; this is reflected by the accumulation of both hormones and secretory granules in pituitary tissue. The strict correlation between the size of the GH and TSH populations with stimulation and inhibition of hormonal secretory activity reported in this investigation further supports the critical role played by the cell renewal process in endocrine secretion.

The mRNA for rat liver serine dehydratase, a gluconeogenic enzyme, exhibits a circadian rhythm with a maximum at the onset of darkness marking the end of the fasting period and a minimum at the onset of light that marks the end of the feeding period, when rats have free access to food and water. In situ hybridization with an antisense cRNA probe revealed that serine dehydratase mRNA was localized in the periportal area of rat liver parenchyma in the evening, whereas it was scarce in the liver in the morning. The predominant localization of serine dehydratase mRNA in the periportal area also occurred in livers of rats that underwent laparotomy, glucagon and dexamethasone administration, and streptozotocin-induced diabetes mellitus, all of which are known to induce serine dehydratase mRNA levels remarkably. Immunostaining revealed that the localization of serine dehydratase protein agreed with that of succinate dehydrogenase, another enzyme known to be predominant in the periportal zone. Thus, the periportal serine dehydratase gene expression strongly supports the idea of metabolic zonation that gluconeogenesis from amino acids occurs preferentially in the periportal parenchyma of rat liver.

At neutral pH, poly-L-lysine-gold complexes labelled the predentine extensively, whereas in dentine the number of gold complexes was reduced by half. Hyaluronidase pretreatment of the section at pH 6.8, prior to labelling, suppressed most of the staining in predentine and did not affect dentine. In contrast, alkaline phosphatase pretreatment at pH 9 enhanced the gold complex labelling in predentine and removed most of the labelling in dentine. This proves that at pH 7.2, the polyanions which are stained include a heterogeneous population of glycosaminoglycans, located in predentine, and phosphoproteins, visualized in dentine. At acidic pH levels (2.9 and 1.1), the number of scored gold complexes decreased, but the ratio between predentine and dentine labelling remained constant. Hyaluronidase pretreatment removed or firmly reduced the gold complex labelling both in predentine and dentine, whereas alkaline phosphatase pretreatment of the sections at pH 9 prior to labelling did not induce any change. This argues in favour of an increased specificity of polylysine-gold complex staining for glycosaminoglycans, stained at low pH in both predentine and dentine. Differential staining of glycosaminoglycans and phosphoproteins according to the pH provides a useful tool for studying the role played respectively by the two matrix components in dentine mineralization.

Previous in situ hybridization studies from our laboratory have shown that expression of certain milk protein genes, e.g. alpha-lactalbumin, is very high in most parts of the mammary glands of sheep and cattle, while in other areas containing an abundance of fat globules it is virtually zero (Molenaar et al., 1992). One possible explanation is that some areas of the mammary gland are dedicated to protein synthesis and some to fat synthesis. To check this possibility, the cRNA for butyrophilin, a milk-fat globule membrane protein, and hence a putative marker of milk fat synthesis, was used as a probe in in situ hybridization studies. The results show quite clearly that the patterns of expression for this gene are similar, cell type for cell type, as those for milk protein genes such as alpha-lactalbumin and alpha S1casein. In addition, we found that butyrophilin gene expression more closely matches that of alpha S1casein than that of alpha-lactalbumin. If it is shown in the future that butyrophilin is indeed a marker for milk fat synthesis, then these results support the current assumption that fat and protein synthesis do occur in the same cell.