Immunohistochemical distribution of inwardly rectifying K+ channels in the medulla oblongata of the rat

The inwardly rectifying K+ channels, Kir1.1, Kir2.3 and Kir4.1-Kir5.1, are the candidate chemosensory molecules for CO2/H+. We determined the mRNA expression and immunohistochemical localization of these channels in the medulla oblongata of the rat. RT-PCR analysis revealed mRNAs of Kir1.1, Kir2.3, Kir4.1 and Kir5.1 were detected in the medulla. The immunoreactivities for Kir1.1, Kir2.3, Kir4.1, and Kir5.1 were observed in the medulla, and immunolabeling pattern was varied by the subunit. Immunoreactivities for Kir1.1 and Kir2.3 were observed in the nerve cell bodies and glial cells both in the chemosensory areas [nucleus tractus solitarius (NTS), nucleus raphe obscurus (RO), pre-B?tzinger complex (PreB?tC)] and non-chemosensory area [hypoglossal nucleus (XII), inferior olive nucleus (IO)]. Kir4.1 immunoreactivity was observed in the glial cells and neuropil, especially in XII and IO. Kir5.1 immunoreactivity was observed in the nerve cell bodies in the XII, RO, and PreB?tC, but not in the NTS or IO. In the NTS, a dense network of varicose nerve fibers showed immunoreactivity for Kir5.1. Our findings suggest that Kir channels may not act specific to the central chemoreception, but regulate the ionic properties of cellular membranes in various neurons and glial cells.     

Immunocytochemical and morphometric studies on the effects of dehydration on vasopressin-secreting cells in the hypothalamus of the Mongolian gerbils.

Effects of dehydration on vasopressin-secreting cells (VP cells) of the supraoptic nucleus (SON) and the paraventricular nucleus (PVN) in the Mongolian gerbils were studied immunocytochemically and morphometrically. The plasma osmolality was measured at the time of sacrifice of individual animals and the body weight was measured every day during dehydration. The plasma osmolality increased significantly on day 3 of dehydration, followed by a gradual increase to reach nearly its equibilium state on day 10. The body weight decreased rapidly until day 10, followed by a gradual decrease thereafter. The area of VP cells increased significantly in both the SON and PVN on day 1 of dehydration, the level being nearly the same until days 3 to 5 and going up on day 7 to reach the plateau after day 15. These findings seem to reflect a compensation mechanism between the volume of body fluid and the plasma osmolality and to reflect responses of VP cells to the osmotic stimuli. Electron microscopic observation revealed that, at the beginning and late stages of dehydration, the increase in the area of VP cells was in parallel with the expansion of the Golgi area and with the distension of cisternae of the rough endoplasmic reticulum.     

Immunohistochemical studies on the differential maturation of three types of olfactory organs in the rats

Differential maturation of three types of olfactory organs, the olfactory epithelium (OE), the vomeronasal organ (VNO) and the septal olfactory organ of Masera (MO), was examined immunohistochemically in embryonic and newborn rats by the use of antiprotein gene product 9.5 (PGP 9.5) serum. These olfactory organs were derived in common from the olfactory placode as neuroepithelia. In the OE, PGP 9.5-immunopositive olfactory cells first appeared at 13 days of gestation. The OE maturated completely, and showed the same cytological features as in the adult at 20 days of gestation. The MO first appeared as a dense mass of PGP 9.5-immunopositive sensory cells on the most ventrocaudal part of the nasal septum at 15 days of gestation and was evidently isolated from the OE by the decrease of immunopositive cells in the intercalated epithelium between the OE and the MO at 20 days of gestation. However, even at 7 days after birth, the MO did not complete its development and contained sensory cells aggregating in the mass. The VNO was separated from the nasal cavity at 13 days of gestation as a tubular structure of a neuroepithelium including PGP 9.5-immunopositive sensory cells. These cells gradually increased in number in the sensory epithelium of the VNO and extended their dendritic processes to the free surface at 7 days after birth. These findings clarified the differential maturation of these olfactory organs. That is, the OE completes its development before birth, while the MO and VNO after birth.     

Expression of the sweet receptor protein, T1R3, in the human liver and pancreas

The expression of T1R3, a taste receptor essential for the perception of sweetness and umami-taste, was examined by immunohistochemistry to determine whether and where it may be localized in the liver and pancreas. In the liver, both immunopositive and immunonegative reactions were detected; bile ducts and intercalated portions of the bile ductules were immunopositive to T1R3, while arterioles and venules were immunonegative in interlobular connective tissue. In the hepatic lobule, all other cells including liver cells (hepatocytes) and bile capillaries were immunonegative. In the pancreas, all endocrine portions of the pancreas were immunonegative to T1R3. Within the exocrine portions, immunopositive reactions were detected in excretory duct cells, intercalated cells, and centroacinar cells. In contrast, acinar cells were immunonegative, as were vessels, lymph capillaries, nerve fibers, and connective tissue cells in the exocrine portions. The restricted localization of T1R3 in the duct cells of the liver and pancreas in the present study may indicate that T1R3 is involved in monitoring changes in the makeup of bile and pancreatic juices in the hepatic and pancreatic duct systems.     

Morphometrical analysis of the kidney from nonobese diabetic (NOD) mice in the non-diabetic stage

The kidneys of non-diabetic NOD and wild type ICR mice were examined morphometrically at 3 and 6 months of age. Kidney weights and diameter of renal corpuscles of non-diabetic NOD mice were less than those of ICR mice. No lesions were observed in glomeruli or uriniferous tubules. Renin-positive areas were more common in NOD mice than in ICR mice, but no differences were detected in the Western blot analyses.     

Differential expression of histochemical characteristics in the developing olfactory receptor cells in a flatfish, barfin flounder (Verasper moseri)

Differentiation of the histochemical characteristics of the olfactory receptor cells (ORC) was examined by immunohistochemistry for protein gene product 9.5 (PGP 9.5) and calretinin (CR) and lectin histochemistry for Phaseolus vulgaris agglutinin-L (PHA-L) in the developing olfactory epithelium (OE) of the barfin flounder. PGP 9.5 immunoreactivity was diffuse and CR immunoreactivity was restricted at day 7, but these immunoreactivities became intense in the OE toward day 91. Crypt cells were first identified at day 56. PHA-L staining was faint at day 28, but became intense toward day 91. These findings suggest that PGP 9.5-immunopositive cells, CR-immunopositive cells, crypt cells and PHA-L-reactive cells differentiate independently in the developing OE and constitute subsets of the ORC in the OE.     

Retrospective study of porcine circovirus 2 infection in Japan: seven cases in 1989

Retrospectively, we demonstrated that seven pigs necropsied in 1989 had characteristic porcine circovirus 2 (PCV-2) lymphoid tissue lesions of severe lymphoid depletion, syncytial giant cell formation, and intracytoplasmic inclusion bodies in macrophages. Immunohistochemically, PCV-2 antigen was detected in these tissues and the distribution of positive staining corresponded to the distribution of inclusion bodies. Electron microscopy demonstrated viral particles compatible with porcine PCV-2. Therefore, the disease occurred in Japan as early as 1989.     

Giant nonlocality near the Dirac point in graphene

Transport measurements have been a powerful tool for discovering electronic phenomena in graphene. We report nonlocal measurements performed in the Hall bar geometry with voltage probes far away from the classical path of charge flow. We observed a large nonlocal response near the Dirac point in fields as low as 0.1 tesla, which persisted up to room temperature. The nonlocality is consistent with the long-range flavor currents induced by the lifting of spin/valley degeneracy. The effect is expected to contribute strongly to all magnetotransport phenomena near the neutrality point.     

Cloning and expression of the human interleukin-6 (BSF-2/IFN beta 2) receptor

Interleukin-6 (IL-6/BSF-2/IFN beta 2) is a multifunctional cytokine that regulates the growth and differentiation of various tissues, and is known particularly for its role in the immune response and acute phase reactions. A complementary DNA encoding the human IL-6 receptor (IL-6-R) has now been isolated. The IL-6-R consists of 468 amino acids, including a signal peptide of approximately 19 amino acids and a domain of approximately 90 amino acids that is similar to a domain in the immunoglobulin (Ig) superfamily. The cytoplasmic domain of approximately 82 amino acids lacks a tyrosine/kinase domain, unlike other growth factor receptors.     

Mechanism of self-sterility in a hermaphroditic chordate

Hermaphroditic organisms avoid inbreeding by a system of self-incompatibility (SI). A primitive chordate (ascidian) Ciona intestinalis is an example of such an organism, but the molecular mechanism underlying its SI system is not known. Here, we show that the SI system is governed by two gene loci that act cooperatively. Each locus contains a tightly linked pair of polycystin 1-related receptor (s-Themis) and fibrinogen-like ligand (v-Themis) genes, the latter of which is located in the first intron of s-Themis but transcribed in the opposite direction. These genes may encode male- and female-side self-recognition molecules. The SI system of C. intestinalis has a similar framework to that of flowering plants but utilizing different molecules.