Yukio Oomori

Immunocytochemical Study of the Gastroenteropancreatic Endocrine Cells of the Sheep

The gastroenteropancreatic (GEP) endocrine cells of the sheep were studied immunocytochemically and their distribution and frequency were determined. Eleven types of endocrine cells were revealed. In the abomasum, somatostatin-, gastrin-, glucagon- and glicentin-immunoreactive cells were detected with the highest frequency in the pyloric region. In the small intestine, somatostatin-, gastrin-, CCK-, motilin-, neurotensin-, secretin-, substance P-, glucagon-, glicentin- and BPP-immunoreactive cells were found and were most numerous in the duodenum except for neurotensin-, glucagon- and glicentin-immunoreactive cells which were more concentrated in the ileum. In the large intestine, somatostatin-, substance P-, glucagon-, glicentin- and BPP-immunoreactive cells were localized with the last three cell types being more concentrated in the rectum. In the pancreas, somatostatin-, glucagon-, glicentin-, BPP- and insulin-immunoreactive cells predominated within the islets and were also scattered in the exocrine portion and rarely detected in duct epithelial cells. The differences between the distribution and frequency of the GEP endocrine cells of the sheep and those of monogastric species are discussed.

Immunohistochemical and histochemical evidence for the presence of noradrenaline, serotonin and gamma-aminobutyric acid in chief cells of the mouse carotid body

The immunohistochemical study revealed tyrosine hydroxylase (TH), dopamine β-hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), serotonin, glutamate decarboxylase (GAD) and γ-aminobutyric acid (GABA) immunoreactivities in the mouse carotid body. TH and DBH immunoreactivities were found in almost all chief cells and a few ganglion cells, and in relatively numerous varicose nerve fibers of the carotid body. The histofluorescence microscopy showed catecholamine fluorescence in almost all chief cells. However, no PNMT immunoreactivity was observed in the carotid body. Serotonin, GAD and GABA immunoreactivities were also seen in almost all chief cells of the carotid body. From combined immunohistochemistry and fluorescence histochemistry, catecholamine and serotonin or catecholamine and GABA were colocalized in almost all chief cells. Thus, these findings suggest that noradrenaline, serotonin and GABA may be synthesized and co-exist in almost all chief cells of the mouse carotid body and may play roles in chemoreceptive functions.

Ganglion cells immunoreactive for catecholamine-synthesizing enzymes, neuropeptide Y and vasoactive intestinal polypeptide in the rat adrenal gland

Immunohistochemistry has been used to demonstrate tyrosine hydroxylase (TH), dopamine-β-hydroxylase (DBH), phenylethanolamine N-methyltransferase (PNMT), neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) immunoreactivities, and acetylcholinesterase (AChE) activity was demonstrated in rat adrenal glands. The TH, DBH, NPY and VIP immunoreactivities and AChE activity were observed in both the large ganglion cells and the small chromaffin cells whereas PNMT immunoreactivity was found only in chromaffin cells, and not in ganglion cells. Most intraadrenal ganglion cells showed NPY immunoreactivity and a few were VIP immunoreactive. Numerous NPY-immunoreactive ganglion cells were also immunoreactive for TH and DBH; these cells were localized as single cells or groups of several cells in the adrenal cortex and medulla. Use of serial sections, or double and triple staining techniques, showed that all TH- and DBH-immunoreactive ganglion cells also showed NPY immunoreactivity, whereas some NPY-immunoreactive ganglion cells were TH and DBH immunonegative. NPY-immunoreactive ganglion cells showed no VIP immunoreactivity. AChE activity was seen in VIP-immunopositive and VIP-immunonegative ganglion cells. These results suggest that ganglion cells containing noradrenaline and NPY, or NPY only, or VIP and acetylcholine occur in the rat adrenal gland; they may project within the adrenal gland or to other target organs. TH, DBH, NPY, and VIP were colocalized in numerous immunoreactive nerve fibres, which were distributed in the superficial adrenal cortex, while TH-, DBH- and NPY-immunoreactive ganglion cells and nerve fibres were different from VIP-immunoreactive ganglion cells and nerve fibres in the medulla. This suggests that the immunoreactive nerve fibres in the superficial cortex may be mainly extrinsic in origin and may be different from those in the medulla.

Configuration of myoepithelial cells in various exocrine glands of guinea pigs

To study the configuration of myoepithelial cells, we isolated glandular endpieces of various guinea pig glands by collagenase, and visualized the myoepithelial cells by immunohistochemistry for actin, or by Bodipy-phallacidin, under both a light microscope and laser scanning confocal microscopes. In parotid and mandibular glands, the glandular acini were small (about 20–30 μm diameter) and spherical, and each acinus had one or two myoepithelial cells attached that were stellate in shape (central cell body and four to six thin processes). Most of the basal surface of the glandular cells was not covered by myoepithelial cells, and processes often extended to the neighboring acinus. The tubular glandular endpieces of the major sublingual gland, which secretes a mucous substance, were almost fully encircled by bandlike myoepithelial cells (about 3–6 μm wide). Although there were many differences between the lacrimal gland and the Harderian gland (e.g., the secretory product of the lacrimal gland was mucous, and glandular lumina were narrow; the Harderian gland secreted lipids and showed wide lumina), the outer contours of both glandular endpieces were the same (about 50–100 μm diameter, ellipsoid or spherical in shape). In both glands, 5–20 stellate myoepithelial cells were attached onto a glandular endpiece, and their arrangement had a lacy appearance. Actin filaments in myoepithelial cells aggregated and formed bundles in the broad processes and cell bodies. The bundles ran across the cell body, but there was no point where the bundles converged. In the arborization, some distal processes reversed their direction. We conclude that the configuration of myoepithelial cells depends on the outer contour of the glandular endpieces rather than on the secretory material or luminal width. The variety of myoepithelial cell configurations in the different exocrine glands we examined suggests that it is quite difficult to assign to myoepithelial cells the general role of expelling secretory products from glandular lumina. These cells seem to maintain the contour of the glandular endpieces, serving as the exoskeleton of the endpieces.

Satisfactory Remission Achieved by PUVA Therapy in Langerhans Cell Hisiocytosis in an Elderly Patient

Langerhans cell histiocytosis is currently regarded as a reactive proliferative process of Langerhans cells rather than a malignancy. The disease is characterized by Langerhans cell infiltration of skin, lung, bone and other organs. We report a 74‐year‐old man with Langerhans cell histiocytosis who had generalized hemorrhagic and crusted papules. He also had diabetes insipidus. Because he did not have any severe constitutional symptoms or failure of vital organs, we applied topical PUVA treatment to his skin lesions, which responded well to the therapy. Diabetes insipidus, however, remained, in spite of X ray radiotherapy for the pituiary lesion.

Immunocytochemical study of tyrosine hydroxylase and dopamine β-hydroxylase immunoreactivities in the rat pancreas

An immunohistochemical and immunoelectron microscopic study was used to demonstrate tyrosine hydroxylase (TH) and dopamine β-hydroxylase (DBH) immunoreactivities in the rat pancreas. Small TH immunoreactive cells were found in close contact with large TH immunonegative ganglion cells among the exocrine glands and were occasionally found in some islets. Some of these TH immunoreactive cells were also DBH immunopositive. The immunoreaction product was seen diffusely in the cytoplasm and in the granule cores of TH immunoreactive cells. All intra-pancreatic ganglion cells were immunoreactive for DBH, but not for TH. The TH immunoreactive cells were identified as small intensely fluorescent (SIF) cells due to their localization and morphological characteristics and showed no insulin, glucagon, somatostatin or pancreatic polypeptide immunoreactivities. These results indicate that SIF cells may release dopamine or noradrenaline to adequate stimuli while the intra-pancreatic ganglion cells with only DBH may not synthesize catecholamines in a normal biosynthetic pathway. TH immunoreactive nerve bundles without varicosities and fibers with varicosities, associated or unassociated with blood vessels, were found in both the exocrine and endocrine pancreas. Close apposition of TH immunoreactive nerve fibers to the smooth muscle and endothelial cells of the blood vessels was observed. A close apposition between TH immunoreactive nerve fibers and exocrine acinar cells and islet endocrine cells was sometimes found in the pancreas. The immunoreaction product was seen diffusely in the axoplasm and in the granular vesicles of the immunoreactive nerve fibers. Since no TH immunoreactive ganglion cells were present in the rat pancreas, the present study suggests that noradrenergic nerve fibers in the pancreas may be extrinsic in origin, and may exert an effect on the regulation of blood flow and on the secretory acitivity of the acinar cells, duct cells and endocrine cells.

Secretion Mode of the Harderian Gland of Rats after Stimulation by Cholinergic Secretagogues

We studied the morphological changes in rat Harderian glands 30 min after injection of cholinergic secretagogues. In controls, the glands exhibited a tubuloalveolar structure with relatively wide lumina, in which some osmiophilic dense droplets exocytosed from glandular cells were observed. Also two types of glandular cells (type A cells and type B cells sometimes showing exocytotic figures of lipid-secretory vacuoles) and myoepithelial cells were recognized. After injection of carbamylcholine chloride (subcutaneously, 0.1 mg/kg body weight), which has both nicotinic and muscarinic actions, many of the alveolar lumina dilated and contained a small number of osmiophilic droplets. Exocytotic figures in both types of cells and a pronounced decrease in the number of vacuoles in the glandular cells were observed. However, there was no evidence of apocrine or holocrine secretion. The injection of the higher dose of carbamylcholine (1.0 mg/kg) caused fusion of secretory vacuoles in the apical cytoplasm and contraction of myoepithelial cells. Most alveoli showed no clear lumina; their centers were jammed with cytoplasmic fragments and accumulated secretory products. Massive discharge of cytoplasmic fragments containing some secretory vacuoles was often observed. This may be classified as apocrine secretion. Bethanechol chloride (subcutaneous injection, 1.0 mg/kg), a muscarinic agonist, stimulated the Harderian-gland secretion, and enhanced exocytosis was observed. The discharge from the glandular cells, following injection of various doses of carbamylcholine, were almost inhibited by atropine sulfate, a muscarinic antagonist. The present results suggested that the cholinergic systems regulate the secretion of rat Harderian-gland cells which have muscarinic receptors.

Gamma-aminobutyric acid (GABA) immunoreactivity in the mouse adrenal gland

Gamma-aminobutyric acid (GABA) immunoreactivity was revealed by immunocytochemistry in the mouse adrenal gland at the light and electron microscopic levels. Groups of weakly or faintly GABA immunoreactive chromaffin cells were often seen in the adrenal medulla. By means of immunohistochemistry combined with fluorescent microscopy, these GABA immunoreactive chromaffin cells showed noradrenaline fluorescence. The immunoreaction product was seen mainly in the granular cores of these noradrenaline cells. These results suggest the co-existence of GABA and noradrenaline within the chromaffin granules. Sometimes thick or thin bundles of GABA immunoreactive nerve fibers with or without varicosities were found running through the cortex directly into the medulla. In the medulla, GABA immunoreactive varicose nerve fibers were numerous and were often in close contact with small adrenaline cells and large ganglion cells; a few, however, surrounded clusters of the noradrenaline cells, where membrane specializations were formed. Single GABA immunoreactive nerve fibers, and thin or thick bundles of the immunoreactive varicose nerve fibers ran along the blood vessels in the medulla. The immunoreaction deposits were observed diffusely in the axoplasm and in small agranular vesicles of the GABA immunoreactive nerve fibers. Since no ganglion cells with GABA immunoreactivity were found in the adrenal gland, the GABA immunoreactive nerve fibers are regarded as extrinsic in origin.

Immunohistochemical observations of lysozyme in the Paneth cells of specific-pathogen-free and germ-free mice.

The localization of lysozyme, which may function as an antibacterial agent, was immunohistochemically studied on the mouse Paneth cell secretory granules showing bipartite substructures (central core and peripheral halo). The lysozyme immunoreactivity was observed in the core, but not in the halo. Even in germ-free mice, Paneth cells have many secretory granules and their cores show lysozyme immunoreactivity. It seems likely that mice Paneth cells possess the ability to produce secretory granules containing lysozyme in disregard of the intestinal bacterial milieu.

Gamma-Aminobutyric Acid Immunoreactivity in the Enterochromaffin Cells of the Rat Stomach

The present immunocytochemical study revealed gamma-aminobutyric acid (GABA) immunoreactivity in the oxyntic and pyloric mucosa of the rat stomach at light- and electron-microscopic levels. GABA-immunoreactive endocrine cells were numerously seen in the lower half portion of the pyloric mucosa but rarely in the oxyntic mucosa. These cells were round or oval in shape and sometimes had a short cytoplasmic process. Serotonin-immunoreactive enterochromaffin (EC) cells were also observed in the oxyntic and pyloric mucosa of the stomach. The distribution and shapes of the immunoreactive cells were similar to those of the GABA-immunoreactive cells. With a double immunolabeling technique using anti-GABA and antiserotonin serum, GABA-immunoreactive endocrine cells showed serotonin immunoreactivity and were identified as EC cells. At the electron-microscopic level the GABA-immunoreactive cells contained round or oval, spindle-like, pear-shaped granules in EC cells. The immunoreaction product in the EC cells was generally confined to the granular cores. These findings suggest that GABA may be synthesized in the EC cells and be released from the granules of the cells after adequate stimuli.