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O Ohtani

Publications and source records attributed to O Ohtani.

At least 55 records · Page 3Linked to original sources
PubMed1987

Blood vascular architecture of the rat cerebral hypophysis and hypothalamus. A dissection/scanning electron microscopy of vascular casts.

Complete casts of the hypophyseal and hypothalamic blood vascular beds of newborn, pubescent, adult and aged rats were produced by infusion of low viscosity methacrylate media, dissected under a binocular light microscope, and observed with a scanning electron microscope. The primary capillary plexus projected capillary loops into the median eminence and infundibular stalk. These loops were composed of anastomosing capillaries, being numerous in the central area of the anterior lip of the median eminence. The well developed long loops received their proper afferent arterioles from the arterial terminals in the primary plexus, and emitted their proper efferent venules continuous with the long portal vessels. The loops in newborn rats were poorly developed, appearing as simple ball-like protrusions of the capillaries of the primary plexus. Many branches of the anterior, middle and accessory middle hypophyseal arteries penetrated the primary plexus, and ascended as infundibular ascending arterioles in the median eminence and infundibular stalk. These infundibular ascending arterioles continued into the capillary bed of the hypothalamus, especially in its basilar and peri-ventricular areas. The subependymal capillary network was fairly independent, and located dorsal to the loops. This network received some of the infundibular ascending arterioles, and emitted infundibular descending venules continuous with the long portal vessels. The subependymal network also received the infundibular descending arterioles from the hypothalamic arteries, and emitted the infundibular ascending venules continuous with the hypothalamic veins. Thus, neither a feedback nor a retrograde portal route from the hypophyseal capillaries to the hypothalamic capillaries was noted. The capillary bed of the pars tuberalis was observed only in the adult and aged rats; it was a very coarse network which was derived from the primary capillary plexus and connected to the secondary capillary plexus.

Aging↗
PubMed1987

Three-dimensional organization of the connective tissue fibers of the human pancreas: a scanning electron microscopic study of NaOH treated-tissues.

A method for scanning electron microscope (SEM) study of reticular fibers in their original shapes and locations is described. This technique was employed to demonstrate the three-dimensional organization of the reticular fibers of the human pancreas. The cellular elements were effectively removed by treatment of the tissue pieces with a 10% aqueous solution of NaOH for 3-4 days at room temperature. Thin layers of the reticular fibers surrounding the acini and ducts formed a three-dimensional interstitial compartment. The reticular fiber sheaths for the blood vessels coursed through the compartment. In the lobule, there were scattered round or oval capsules for the islets of Langerhans. The capsule also consisted of reticular fibers. Within the capsule, reticular fiber sheaths for accommodating islet capillaries, representing the pericapillary spaces, formed a three-dimensionally anastomosing network. The channels for the capillaries ensheathed by the reticular fibers in the islet were continuous with those in the surrounding exocrine pancreas; thus, the insulo-acinar portal system was confirmed to exist in the human pancreas. This study also maintains that the present method is useful for examining the microvascular organization of the islet.

Aged↗
PubMed1987

Lymphatics and myenteric plexus in the muscular coat in the rat stomach: a scanning electron microscopic study of corrosion casts made by intra-arterial injection.

Intra-arterially injected low viscosity methacrylate filled the lymphatic system in the muscularis externa of the young rat. Scanning electron microscopy of the corrosion casts revealed that between the inner and outer muscular coat there was a lymphatic network made up of polygonal meshes. The initial lymphatics, about 15 micron diameter drained into the thicker lymphatics, about 20-80 micron diameter. These lymphatics ran along the muscular fibers of either inner or outer layers and formed polygonal (most often rectangular) meshes. The casts of the thicker lymphatics possessed notches indicative of valve locations. The myenteric nervous plexus was also replicated between the inner and outer muscular coats. The plexus consisted of flat astral structures with primary and secondary, and occasionally, tertiary, processes which interconnected with neighboring ones. It is suggested that the enteric neurons are confined in an interconnected channel system.

Animals↗
PubMed1986

Three-dimensional organization of the lymphatics in the rabbit appendix. A scanning electron and light microscopic study.

The three-dimensional organization of the lymphatics in the rabbit appendix was demonstrated by scanning electron microscopy of lymphatic corrosion casts and intact tissues. In the glandular mucosa a polygonal network of lymphatics led into perpendicularly oriented lymphatics continuous with the lymphatics in the thymus-dependent area. In the thymus-dependent area a plexus consisting of anastomosing tubular lymphatics led into the upper ends of the perifollicular sinuses. Each follicle was surrounded by a well-developed perifollicular sinus. From the bottoms of the sinuses thin lymphatics descended into the submucosal lymphatics. The cast of submucosal lymphatics showed notches corresponding to the locations of bicuspid valves. Lymphocytes migrating through the lymphatics and high-endothelial venules were only observed in the thymus-dependent area. The results indicate that the potential capacity of the perifollicular sinuses as a reservoir and as a drainage route for fluid and lymphocytes is great, but that the lymphatics in the thymus-dependent area are sites for lymphocyte migration from the follicles into the lymphatics. The well-developed lymphatic network in the glandular layer suggests great participation in fluid flux.

Animals↗
PubMed1986

Microcirculation of the pancreas in the rat and rabbit with special reference to the insulo-acinar portal system and emissary vein of the islet.

Microcirculation of the pancreas in the rat and rabbit with special reference to the islets was studied by scanning electron microscopy (SEM) of vascular corrosion casts, light microscopy (LM) of India ink-injected/cleared tissues, and intravital microscopy of in situ organs. The following observations were made: Approximately 10-20% of the total terminal arterioles supplied the islets, while the remainder directly supplied the exocrine pancreas. The vas afferens of the islets divided into sinusoidal capillaries with frequent U-shaped turns in the cortical A and D cell area of the islets, and their secondary branches supplied the core B cell area. Intravital microscopy confirmed that blood irrigated the cortex of the islets first and the core portion second. All islets observed possessed insulo-acinar portal vessels. About 60% of the islets in the rat possessed emissary veins leading directly into the systemic circulation, while in the rabbit, less than 5% of islets possessed emissary venules of small diameter. Thus, the well-developed emissary veins of the islets seemed characteristic of the rat, as compared with the rabbit and several other mammals examined previously. The insulo-acinar portal system seems to represent a short vascular route through which islet secretions are transported in high concentrations to the exocrine pancreas, there to exert their actions. The emissary veins of the islet seem to serve for the quick conveyance of insular secretions into general circulation. It is suggested that the pancreatic lobule is made up of subdivisions or microcirculatory units, each of which is supplied centrally by the insulo-acinar portal system, while peripherally the unit also receives direct branches of intralobular arterioles. The veins run the periphery of the unit. The occurrence of sphincters in the vas afferens and the emissary veins of the islets is suggested as being involved in the regulation of the islet blood flow.

Animals↗
PubMed1985

Three-dimensional organization of lymphatics and their relationship to blood vessels in rabbit small intestine. A scanning electron microscopic study of corrosion casts.

Casts of small intestinal blood vessels and lymphatics in the rabbit were made with methacrylate and observed under a scanning electron microscope (SEM). In casting the lymphatics, a specially diluted low viscosity medium was injected intraparenchymally into the intestinal submucosa. This parenchymal injection allowed good reproduction of fine lymphatics, including the initial lacteals in the villi. The central lacteals were completely surrounded externally by the subepithelial blood capillary networks of the intestinal villi. Individual villi in the lower intestine contained only one central lacteal that drained through a thin lymphatic in the glandular layer into the submucosal lymphatic plexus. Villi in the upper small intestine were broader than those in the lower small intestine, and contained two to five lacteals. They anastomosed with each other at the villous base and formed a markedly expanded sinus. The cast submucosal lymphatics frequently showed constrictions strongly suggestive of valves. It was constantly observed that well-developed lymphatics in the submucosa ran in pairs and held an arteriole or artery between them. This close association of the lymphatics with arteries suggests that arterial vasomotion might provide an important hydrodynamic energy source for lymph formation and transport.

Animals↗
PubMed1985

Blood vascular bed of the rat pituitary intermediate lobe, with special reference to its development and portal drainage into the anterior lobe. A scanning electron microscope study of vascular casts.

Blood vascular beds of the rat pituitary intermediate lobes were reproduced by injection of low viscosity methacrylate media, and then observed with a scanning electron microscope. Although the intermediate lobes of newborn and pubescent rat were poorly vascularized, the adult rat intermediate lobe contained numerous capillaries forming a fairly independent network whose density, however, was not so great as in the anterior and posterior lobes. The vascular network of the intermediate lobe could be divided into two parts: a superficial plexus close to the anterior lobe, and a deep one close to the posterior lobe, though the two plexuses were continuous with each other. The superficial plexus consisted of anastomosing capillaries, and the deep one of non-anastomosing capillaries with a palisade-fashioned arrangement. The superficial plexus seemed crucially important for the blood supply of the intermediate lobe since it developed or thickened as the animals aged. The superficial plexus received its proper afferent vessels from the middle and posterior hypophyseal arteries and emitted its proper efferent vessels continuous with the sinusoidal capillaries of the anterior lobe. The capillaries of the deep plexus usually communicated with the arterial capillaries of the posterior lobe and possibly represented another afferent route to the superficial plexus. This paper, thus, strongly suggests a portal circulation from the intermediate lobe to the anterior lobe though its functional significance is unknown.

Aging↗
PubMed1984

Review of scanning electron and light microscopic methods in microcirculation research and their application in pancreatic studies.

The methods reviewed here include: scanning electron microscopy (SEM) of vascular corrosion casts, SEM of intact tissue, SEM of HCl-collagenase treated tissues, light microscopy (LM) of India ink or silicon rubber injected tissues, with stereomicrography, LM of tissue stained by perfusion with hematoxylin, and a correlative study of intravital microscopy with SEM of vascular corrosion casts or LM of India ink-injected tissue. The last technique allowed for both the examination of the microvascular architecture and blood flow in a particular tissue area. This paper shows that an adequate understanding of the microvasculature of the pancreas can only be gained when a variety of SEM techniques, together with other LM and TEM techniques are employed in a coordinated fashion. The intralobular arterioles of the pancreas supply the islets of Langerhans, exocrine acini, and duct system. Blood leaving the islets flows into the capillaries in the exocrine region through the insulo-acinar portal system and insulo-ductular portal system, although some fraction of the blood drains through venules into nearby veins. Thus, these studies in the pancreas indicate that the islets of Langerhans are situated in the center of the pancreatic microcirculatory bed so that the insular secretions are transferred in high concentrations through short vascular routes to the exocrine region of both the duct system and acini, presumably to act upon these structures.

Animals↗
PubMed1984

The microvascular architecture of the rabbit stomach corpus in vascular corrosion casts.

The blood vessels of the rabbit gastric mucosa were reproduced with a methacrylate casting medium and observed in a scanning electron microscope. The submucosal arteries gave off short and long arterioles. The short arterioles connected at the base of the fundic glands with the capillary network surrounding the glands. The long arterioles ascended along the glands and supplied the capillary network beneath the surface epithelium. This capillary network was denser than the capillary network around the glands. In the glandular neck region, there were many capillary connections between the surface epithelial and glandular capillary systems, but both of these capillary networks drained into common venules which descended along the glands and emptied into the submucosal veins. The isolated arterial supply of the surface mucous cell layer may assure enough blood circulation in this layer for the surface mucous cells to produce a sufficient amount of HCl-resistant mucous or to protect the epithelium against the acid in the gastric lumen.

Animals↗
PubMed1983

The microvasculature of rat salivary glands. A scanning electron microscopic study.

The blood vessels together with the parenchymal components of rat salivary glands were studied by scanning electron microscopy (SEM) after removal of stromal connective tissue by acid hydrolysis plus enzymatic digestion. The three-dimensional vascular architecture was also studied by SEM of vascular corrosion cats. Each cluster of 4-5 polymorphous acini is connected with the convoluted duct via an intercalated duct. The convoluted duct usually has a sigmoid course and drains to the intralobular striated duct (about 20 microns in diameter); this has a rather straight course before connecting with the interlobular excretory duct. Myoepithelial cells with radiating processes were observed on the stromal surface of the secretory acini. Pericytes with longitudinal and circular processes were also observed surrounding the stromal surface of capillaries. The acini and convoluted ducts are surrounded by plexuses of capillaries derived from terminal arterioles which run along the intralobular duct system. The sinusoidal capillary plexus enveloping the striated duct receives blood from capillaries surrounding the acini and convoluted ducts through portal venules. The interlobular excretory ducts are richly supplied by a subepithelial network of capillaries which receive blood directly from the interlobular artery and drain into the interlobular vein. Thus, the excretory duct circulation is separated from the intralobular circulation. No arterio-venous anastomoses were observed in the gland. However, veno-venous and arterio-arterial anastomoses were often seen along the excretory duct; such anastomoses may participate in controlling the direction of blood flow through the vascular plexus around the excretory duct. The well-developed subepithelial plexus of capillaries observed around this duct is appropriate for its known absorptive/secretory functions. The capillary network around the acini is densest in the parotid gland and sparsest in the sublingual gland. The subepithelial capillary network of the excretory ducts of the submaxillary gland is denser than those of the other two glands which had similar densities.

Animals↗
PubMed1983

Zinc-binding proteins of newborn rat epidermis.

Hematoxylin stain was used to demonstrate localization of Zn2+-binding proteins in the skin of the newborn rat. The binding protein showed different solubilities and the zinc binding was dissociated at pH 4.5. Epidermal proteins were extracted stepwise in Tris-HCl buffer containing NaCl at 4 degrees C and 37 degrees C, 1 M potassium phosphate, and 4 M urea. Zn2+-binding protein was obtained from each extract by means of Zn2+ chelate affinity chromatography. We detected elution of histidine-rich protein from the affinity column with a pH 4.5 buffer by 3H-histidine labeling and immunoreactivity to rabbit IgG directed to histidine-rich protein. Amino acid analysis demonstrated that the compositions of the Zn2+-binding proteins soluble in the different extracts not only resemble each other, but are essentially the same as those of histidine-rich protein of the newborn rat skin as previously reported. However, sodium dodecylsulfate gel electrophoresis showed multiple protein bands ranging from Mr less than 25,000 to Mr greater than 200,000. The findings indicate that histidine-rich protein of different forms and solubility exists, in the epidermis and may be involved in the biological function of the cells through metal-binding.

Amino Acids↗
PubMed1983

Microvasculature as studied by the microvascular corrosion casting/scanning electron microscope method. I. Endocrine and digestive system.

This paper reviews firstly the microvascular corrosion casting/scanning electron microscope method and secondly the microvascular organization of endocrine and digestive system as revealed by this technique. Detailed descriptions of the microvascular arrangement of the hypophysis, pineal body, thyroid gland, pancreas, adrenal gland, salivary gland, liver, stomach and small intestine are given. Various hypotheses are also proposed regarding the physiological significance of the microcirculatory patterns observed.

Adrenal Glands↗
PubMed1983

Conductive staining of biological specimens for scanning electron microscopy with special reference to ligand-mediated osmium impregnation.

Biological specimens for scanning electron microscopy are made electron-conductive and non-charging by intense osmication with tannic acid, thiocarbohydrazide, hydrazine hydrate or other bifunctional ligands (or mordants). Such osmication also minimizes tissue shrinkage during dehydration and drying, reduces tissue damage during metal coating and scanning observations, and circumvents the use of a thick metal coating which hinders high resolution. Intense osmication when repeated eliminates the need for a metal coating and produces a well-contrasted scanning image with good resolution. Moreover, such osmication reduces tissue damage during ion implanting, enhances the depth of imaging, allows x-ray microanalysis without coated metals, and permits resin-embedded observations, as well as continuous or repeated microdissections in the scanning electron microscope without charging. Intense osmication forms a surface coat or thickens the cell membrane. This surface coat consists of electron dense deposits of 4-20 nm thickness. The hydrazine hydrate-osmium method can be used in the vapor phase. The vapor phase application has the advantage of staining even plastic samples for non-metal-coated scanning electron microscopy.

Animals↗
PubMed1983

Microcirculation of the pancreas: a correlative study of intravital microscopy with scanning electron microscopy of vascular corrosion casts.

The microcirculation of the pancreas in anesthetized rats was examined by intravital microscopy. Scanning electron microscopic observation of vascular corrosion casts of the same parts of the pancreas as viewed light microscopically in vivo, allowed detailed analysis of microcirculation in particular vessels. Blood vessels with flowing blood cells were clearly observed under incident ultraviolet illumination following systemic injection of an intravascular fluorescent tracer. The islets of Langerhans were easily identified by their brighter appearance than the exocrine portions under incident ultraviolet illumination. Blood leaving the islets passed through the insulo-acinar portal vessels into the capillary network around the acini. The periductular plexus received blood from the periacinar capillary network via either venules or capillaries as well as directly from the inter- or intralobular arteries. The periductular plexus also received blood from the islets located close to the ductules. The results obtained show blood in the pancreas flowing in a manner in which it carries insular secretions in high concentrations through short and direct vascular routes from the islets to the pancreatic exocrine tissues, including their duct system.

Animals↗
PubMed1983

Generation of biologically active, complement-(C5) derived peptides by cathepsin H.

The thiol proteinase cathepsin H, isolated and purified from rat liver lysosomes, provokes acute inflammation characterized by the accumulation of polymorphonuclear leukocytes (PMN) when injected intracutaneously into newborn rats. We have examined the possibility that the accumulation of PMN at skin sites injected with cathepsin H is due, in part, to generation locally of C-derived chemotactic factors. We have found that cathepsin H acts in a concentration- and time-dependent fashion in whole human (and rat) EDTA-plasma to generate C5-derived peptides with chemotactic activity for PMN. Chemotactic activity was not generated in EDTA-plasma by either heat-inactivated cathepsin H or by a combination of active enzyme and a thiol proteinase inhibitor isolated from rat epidermis. Cathepsin H also acted in a concentration- and time-dependent fashion on isolated (functionally pure) human C5 to yield chemotactic activity for PMN as well as PMN lysosomal enzyme-releasing activity. Whereas 10 ng/ml cathepsin H generated significant chemotactic activity from isolated C5 (1000 CH50 U/ml), 7 to 10 micrograms/ml were required to generate chemotactic activity in whole EDTA-plasma. Cathepsin H not only was capable of generating biologically active, C5-derived peptides, but also was capable of degrading these peptides. Incubation of either whole EDTA-plasma or isolated C5 with high concentrations of cathepsin H (e.g., 25 micrograms/ml and 100 ng/ml, respectively) caused the rapid appearance of chemotactic activity followed by an equally rapid disappearance. PMN accumulated more rapidly in the skin of newborn rats injected with cathepsin H-treated C5 than in the skin of animals injected with cathepsin H alone. These data suggest that generation by cathepsin H of C-derived chemotactic activity contributes to the ability of this enzyme to induce dermal inflammation.

Animals↗
PubMed1982

Further characterization of cysteine proteinase inhibitors purified from rat and human epidermis.

Cysteine proteinase inhibitors isolated from rat and human epidermis were purified to homogeneity and had isoelectric points of pH 4.31 and pH 5.10, respectively, Both inhibitors caused noncompetitive inhibition to the same degree against papain (EC 3.4.22.2), but the activity of human inhibitor against rat liver cathepsins B (EC 3.4.22.1), H (EC 3.4.22.16), and L (EC 3.422.-) was more effective than that of rat inhibitor. Dependency on pH was observed with rat inhibitor for cathepsins B and H, and with human inhibitor for cathepsin L. The reaction of the inhibitors with papain and cathepsins H and L occurred immediately, while the inhibition reaction of cathepsin B increased progressively during a preincubation time up to 40 min. Incubation at pH 7.0 maximized the progressive inhibitory activity. These findings demonstrate that cysteine proteinase inhibitors from rat and human epidermis inhibited a variety of cysteine proteinases. However, the inhibitor and enzyme interaction depends upon the enzyme, inhibitor source, and experimental conditions such as pH and preincubation time.

Animals↗
PubMed1982

Cellular localization of thiol-proteinase inhibitor in the epidermis of the newborn rat.

Subcellular distribution of a thiol-proteinase inhibitor protein was determined in the epidermis of the newborn rat by light and electron microscopy. This protein was highly soluble in basal cells and concentrated on ribosomes in the perinuclear region. Solubility in Tris buffer decreased in granular and cornified cells in which the protein appeared on polysomes which were attached on other cellular structures such as dense homogenous deposits and tonofilaments. The protein also appeared to be deposited on the plasma membrane and became insoluble in Tris buffer at 37 degrees C, but solubilized in 1 M phosphate buffer. Location of the protein around keratohyalin granules or by the plasma membrane suggested that the inhibitor protein bound to cysteine-rich protein of the epidermis with or without forming a thiol-proteinase inhibitor complex. The thiol-proteinase inhibitor protein seems to contribute to epidermal cell differentiation at multiple points through changes in its solubility and subcellular localization from basal cells to cornified cells.

Animals↗