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Biomedical subjects

A Ohtsuka

Publications and source records attributed to A Ohtsuka.

At least 127 records · Page 7Linked to original sources
PubMed1990

[Bronchoconstriction in isocapnic hyperventilation-induced asthma].

It is well known that some asthmatic patients develop bronchoconstriction after exercise challenge (exercise-induced asthma, EIA). Recently, it has been pointed out that isocapnic hyperventilation also induces similar bronchoconstriction (hyperventilation-induced asthma, HIA) in the same asthmatic subjects. However, the mechanism of HIA has not yet been determined. In the present study, we performed exercise and hyperventilation challenge in the same patients and pulmonary function data and neutrophil chemotactic factor (NCF) in peripheral blood were examined before and after both challenges. Twelve asthmatic patients with normal pulmonary function data on testing days were subjected to exercise test on a bicycle ergometer and then isocapnic hyperventilation tests in subsequent days. Subjects breathed dry air from the cylinder. Isocapnic hyperventilation was performed by monitoring minute ventilation and each patient followed the same minute ventilation exercise. The reduction of FEV1.0 and time course of airway obstruction were almost the same after exercise and hyperventilation testing. All patients who developed EIA also developed HIA and other patients did not develop both EIA and HIA. Changes of Rrs, V50 and V25 and their time course after each test were also similar in EIA(+) and HIA(+), and in EIA(-) and HIA(-). NCF increased significantly after both challenges in EIA(+) and HIA(+) patient, although increment of NCF was much less these the increases of HIA(+). These data may suggest that the development of bronchoconstriction was compatible after exercise and hyperventilation in each asthmatic patient, however, the mechanism of HIA may differ from EIA, although NCF slightly but significantly increased in HIA, suggesting the possible role of a chemical mediator.

Adolescent↗
PubMed1989

The blood vascular architecture of the rat thyroid gland: a scanning electron microscope study of corrosion casts.

The blood vascular bed of the rat thyroid gland was reproduced by injection of a methacrylate casting medium and observed with a scanning electron microscope. The rat thyroid gland received the superior and inferior thyroid arteries and emitted the superior and inferior thyroid veins. Anastomosis between the interlobular arteries or between the interlobular veins was frequently observed in the thyroid gland. The arteriovenous anastomosis was rarely observed between the terminal branches of the lobular arteries and veins. The thyroid blood vascular bed was divided into lobular units which consisted of basket-like capillary networks surrounding the thyroid follicles; a small lobular unit consisted of a few networks, whereas a large one of fifty or more networks. Sizes and forms of the networks varied widely in each case. However, the networks in the superficial layers of the lateral parts of the thyroid gland were typically most developed. Regardless of its size and form, each network always received a proper efferent vessel continuous with the lobular vein, though it was sometimes provided with an accessory afferent or efferent vessel. Only occasionally were the adjacent networks fused with each other or connected by transfollicular capillaries. Thus, the present data suggest that each follicular capillary network is a fairly independent functional-unit in the thyroid microcirculation. The capillaries of the network were sinusoidal in nature and sometimes protruded fine projections which indicated the neogenesis of capillaries. The blood vascular bed of the newborn rat thyroid gland was not always differentiated into basket-like capillary networks.

Animals↗
PubMed1989

The blood vascular architecture of the rat testis: a scanning electron microscopic study of corrosion casts followed by light microscopy of tissue sections.

The blood vascular bed of the rat testis was studied by scanning electron microscopy (SEM) of corrosion casts and by light microscopy of tissue sections. The testicular artery penetrates the pampiniform plexus and gives rise to the intertubular arterioles. Each of these arterioles courses in the intertubular connective tissue column, and gives off intertubular and peritubular capillaries. The intertubular capillaries pass the intertubular connective tissue column, whereas the peritubular capillaries reach the peritubular connective tissue sheet. The intertubular and peritubular capillaries anastomose with each other and converge into the intertubular venules in the intertubular connective tissue columns. Thus, the blood vascular bed of the rat testis consists of hexago- or pentago-columnar capillary networks which commonly surround the seminiferous tubules. The Leidig's cells are preferentially observed in the intertubular connective tissue columns. One of the intertubular capillaries is consistently thick, and directly continues into the intertubular venules (arteriolo-venular capillary channels), which finally drain into the pampiniform plexus. These findings suggest that the male sex hormone, testosterone, as secreted by the Leidig's cells, is discharged into the intertubular capillaries and then mainly carried by the arteriolo-venular capillary channels and intertubular venules into the pampiniform plexus. This specialized drainage may ensure the presence of highly concentrated testosterone in the pampiniform plexus and allow the testosterone-exchange from the pamipiniform plexus to the testicular artery. The arteriolo-venular capillary channels may also eliminate blood congestion in the testis to enhance the efficiency of the heat-exchange mechanism between the testicular artery and pampiniform plexus. Many arterio-arterial and arterio-venous anastomoses occur, which may regulate the blood flow within the testis.

Animals↗
PubMed1989

Blood vascular beds of rat adrenal and accessory adrenal glands, with special reference to the corticomedullary portal system: a further scanning electron microscopic study of corrosion casts and tissue specimens.

Blood vascular casts of the rat adrenal glands were observed with a scanning electron microscope. The cortical capillary plexus drains, through the corticomedullary venous radicles, into the subcortical veins continuous with the medullary collecting veins. The medullary capillary plexus drains into the corticomedullary venous radicles, subcortical veins and medullary collecting veins. No portal vessel was noted between the cortical and medullary capillaries. These findings indicate that the cortical blood rich in glucocorticoids preferentially and continuously flows into the corticomedullary venous radicles, subcortical veins and medullary collecting veins all three of which are fenestrated in type, and also suggest that the vascular route from the cortical capillaries to the medullary collecting veins functions as a substitute for the portal system, controlling the biosynthesis of catecholamines in the adrenal medulla. The vascular bed of the accessory adrenal gland (extra-adrenal cortical or chromaffin body) is sometimes annexed to that of the adrenal gland. On rare occasions, the vascular beds of the extra-adrenal cortical and chromaffin bodies fuse with each other. Additional scanning of tissue samples confirmed the direct drainage of cortical capillaries into the medullary veins and also the endothelial fenestrations of these capillaries and veins.

Adrenal Glands↗
PubMed1989

[Role of plasma histamine and neutrophil chemotactic factor in exercise-induced asthma].

The mechanism of exercise-induced asthma (EIA) is still controversial, although the role of chemical mediator is strongly suspected. In the present study, 50 asthmatic patients were observed after exercise on bicycle ergometer during dry air breathing, and changes of plasma histamine and neutrophil chemotactic factor (NCF) were measured and effect of anti-allergic drugs was examined. 31 patients developed postexertional bronchoconstriction and their % reduction of FEV1 after exercise correlated significantly with the degree of airway hyperresponsiveness to inhaled methacholine determined by Astograph. Plasma histamine levels were examined in 20 EIA positive cases and 13 EIA negative cases, but no significant changes were observed between pre- and post-histamine levels in either group. On the other hand, NCF was elevated significantly after exercise in both EIA positive and negative cases, but postexertional NCF levels were significantly higher in EIA positive than in EIA negative cases. The relationship between % increase of NCF and the % reduction of FEV1 after exercise was significant (r = 0.472, p less than 0.05). DSCG and Azelastine protected the development of EIA in 14 out on 19 cases and 7 out of 12 cases, respectively. Pretreatment with DSCG significantly reduced the increase of NCF after exercise. These results indicates that one of the chemical mediator, NCF, may play an important role in producing postexertional bronchoconstriction in asthmatic patients.

Adolescent↗
PubMed1988

Obstructive hydrocephalus due to a giant aneurysm of the internal carotid bifurcation.

A rare case of obstructive hydrocephalus associated with a giant aneurysm of the internal carotid artery is presented. The giant aneurysm, which was located in the prepontine cistern, was initially thought to be of basilar artery origin. Cerebral computed angiotomography had the most diagnostic value in disclosing the partially thrombosed giant aneurysm and its relationship with the surrounding arteries. After undergoing a ventriculoperitoneal shunt operation, the patient's clinical symptoms markedly improved.

Aged↗
PubMed1988

The blood vascular architecture of the extra-adrenal chromaffin body in the adult rat: a scanning electron microscopic study of corrosion casts.

A well developed extra-adrenal chromaffin body with an axis of 200-400 micron was found in seven out of thirty adult male Wistar rats under a stereomicroscope. All seven bodies were located between the left and right kidneys. Blood vascular beds of the five bodies were reproduced with a methacrylate casting medium and observed with a scanning electron microscope. It was revealed that the extra-adrenal chromaffin body contained remarkedly numerous capillaries, which anastomosed with each other to form a conglomerated network. The blood capillaries were of small and uniform caliber and did not represent swollen sinusoids as in the adrenal medulla. The capillary network was denser than that in the adrenal medulla and had no direct vascular linkage with the adrenal cortex or an extra-adrenal cortical body. Histological examination of the two bodies treated with dichromate containing fixatives confirmed that they mainly consisted of chromaffin cells. These findings suggest that in the rat, extra-adrenal chromaffin bodies survive throughout life, actively producing catecholamines.

Adrenal Cortex↗
PubMed1988

Blood vascular architecture of the rat extra-adrenal cortical body: a scanning electron microscopic study of corrosion casts.

A well developed extra-adrenal cortical body with an axis of 200-700 micron was found in eighteen of thirty adult male Wistar rats under a stereomicroscope. All eighteen bodies were located between the kidneys. Blood vascular beds of sixteen of the eighteen bodies were reproduced with a methacrylate casting medium and observed with a scanning electron microscope. The extra-adrenal cortical body was found to contain remarkably numerous capillaries which anastomosed with each other to form a conglomerated network; it received one afferent vessel and issued one to three (usually, one) efferent vessels. The blood capillaries were of sinusoidal and uniform calibers, and resembled those of the adrenal cortex. The network with an axis of 300-700 micron possessed a typical, deep efferent rootlet which corresponds to the central vein of the adrenal gland. Histological examination of the two bodies treated with Orth's or Helley's fixative confirmed that they consisted of non-chromaffin cells similar to those of the adrenal cortex. These findings suggest that in the rat, the extra-adrenal cortical bodies persist throughout life, actively producing cortical hormones.

Adrenal Cortex↗
PubMed1988

The blood vascular wreath of rat ovarian follicle, with special reference to its changes in ovulation and luteinization: a scanning electron microscopic study of corrosion casts.

Blood vascular casts of rat ovaries were prepared by injection of a low viscosity methacrylate medium, and observed by scanning electron microscopy. The proper vascular pattern of the rat ovarian follicle starts as a basket-like wreath of fine capillaries around the primary follicle. As the follicle grows larger, the wreath becomes more developed. The fully developed wreath around the Graafian follicle consists of sinusoidal capillaries. In ovulation, the apical area of the wreath is opened and the basal area of the wreath is elevated. After ovulation, the wreath shrinks and its opened area is closed, with markedly dilated vessels directly continuous with the arterial capillaries. The wreath then transforms, by intense new formation of capillaries, into a conglomerated sinusoidal capillary plexus with an avascular area within it. The avascular area soon disappears by continued intense formation of capillaries, in the plexus, and a complete and dense vascular network of the corpus luteum is formed. The capillaries of the fully developed corpus luteum are small in caliber and not sinusoidal in nature. Discontinuities of the capillaries and a flattening of the efferent branches are the initial signs of the degeneration of the corpus luteum. The small markedly degenerated corpus luteum contains only scattered thready capillaries. The corpus albicans contains few blood vessels.

Animals↗
PubMed1988

The blood vascular architecture of the rat pineal gland: a scanning electron microscopic study of corrosion casts.

The blood vascular bed of the rat pineal gland was reproduced through a low viscosity methacrylate casting medium and observed with a scanning electron microscope. The pineal gland was located in front of the confluens sinuum which was formed by the confluence of the left and right transverse sinuses and the superior sagittal and great cerebral veins. The pineal gland was found to contain a rich vascular network of freely anastomosing capillaries. This network received a few afferent arteries from the posterior cerebral arteries while emitting ten to fifteen efferent veins. Most of these efferent veins drained into the upper segment of the great cerebral vein; the remaining one or two efferent veins continued directly into the confluens sinuum. A marked constriction, probably representing a venous valve or valve-like projection, was observed in the opening area of the great cerebral vein. Circular constrictions, probably representing sphincters, were imprinted in the efferent vessels. No direct vascular connection was noted between the pineal gland and the nervous tissues or between the pineal gland and the choroid plexuses of the third and lateral ventricles.

Animals↗
PubMed1988

Homology of the adductor pollicis and contrahentes muscles: a study of monkey hands.

The deep palmar muscles in monkey hands were studied. The contrahentes muscles mainly arose from the capitate bone, descended palmar to the deep palmar branch of the ulnar nerve and the palmar metacarpophalangeal nerves, and attached to the proximal phalanges or wing tendons of the second, fourth and fifth fingers. In relation to the deep palmar branch of the ulnar nerve and the palmar metacarpophalangeal nerves, the contrahentes muscles are homologous with the adductor pollicis and flexor indicis radialis muscles. The contrahentes muscles occasionally gave off some accessory slips which blended with the interosseous muscles. These findings suggest that the human adductor pollicis muscle is a well-developed remnant of a contrahens muscle, and that the human interosseous muscles contain some remnant of the contrahentes muscle. In fact, a well-developed remnant of a contrahens muscle was found in the fourth finger of a human hand. It is further considered that the human adductor pollicis muscle contains an element of the interosseous muscle of the thumb.

Animals↗
PubMed1988

The interosseous and lumbrical muscles in the human hand, with special reference to the insertions of the interosseous muscles.

The interosseous and lumbrical muscles in twenty-five hands of Japanese adult cadavers were dissected. The palmar and dorsal interosseous muscles continued, with few exceptions, into the wing tendons. The dorsal interosseous muscles gave off tendons which pierced the transverse laminae or passed deep to the transverse laminae, and attached to the bases of the proximal phalanges. The palmar interosseous muscles seldom had such attachments. The palmar and dorsal interosseous muscles sometimes gave off additional tendons which passed superficial to the transverse laminae and attached to the bases of the proximal phalanges. These latter attachments were typical in the contrahentes muscles. Thus, the present findings suggest that the human dorsal interosseous muscles are composite muscles derived from the dorsal abductor, flexor brevis and contrahens muscles, and that the human palmar interosseous muscles are composite muscles derived from the flexor brevis and contrahens muscles. The lumbrical muscles rarely gave off accessory slips with atavistic attachments to the proximal phalanges.

Adult↗
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

Lysine-mediated tissue osmication in combination with a tannin-osmium conductive staining method for non-coated scanning electron microscopy of biological specimens.

Glutaraldehyde fixed rat kidney blocks showed no charging effect when treated with lysine and osmic acid and viewed in a scanning electron microscope using an acceleration voltage of 5-30 kV and a specimen current of 1 X 10(-10) A. The podocyte processes and endothelial micropores of the glomerulus were visible without metal coating. Glutaraldehyde fixed, tannin-osmium impregnated and lysine-osmium treated specimens also showed no charging effect in the scanning electron microscope, yielding instead much clearer scanning images which were comparable to those obtained from gold-coated specimens or from tannin-osmium-thiocarbohydrazide-osmium impregnated specimens (Murakami and Jones, 1980).

Animals↗
PubMed1987

Blood vascular architecture of the rat parathyroid glands: a scanning electron microscopic study of corrosion casts.

Blood vascular beds of the rat parathyroid glands were reproduced with a methacrylate casting medium and observed with a scanning electron microscope. The rat possesses only a single pair (one left and the other right) of parathyroid glands. Each gland was found to contain a rich capillary network which was completely isolated from the capillary plexus of the thyroid gland. Each parathyroid gland received some small afferent arteries from the superior thyroid artery and emitted a thick efferent vein continuous with the superior thyroid vein. The capillary network of the parathyroid gland consisted of freely anastomosing capillaries. The afferent arteries were divided in the superficial and deep layers of the gland. The thick efferent vein arose in the deep layer of the gland. Some small or accessory efferent veins arose in the superficial layers of the gland. These also drained into the superior thyroid vein.

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

A modified method of fine-granular cationic iron colloid preparation: its use in light and electron microscopic detection of anionic sites in the rat kidney glomerulus and certain other tissues.

Ferric chloride, when boiled with hydrazine hydrate and cacodylic acid, is converted into a fine cationic iron (ferric hydroxide) colloid which consists of 0.5-1.5 nm electron-dense granules, and gives a distinct Prussian blue reaction. This colloid allows light and electron microscopic detection of ionized anionic sites in tissues at a wide pH range of 0.8-7.6. It is smaller in size and more stable, and assures longer and greater staining of tissues, especially at low pH levels, than the iron colloid prepared with sodium or ammonium cacodylate by Seno and his associates (1983, 1984, 1985). Some light and electron micrographs of the rat kidney, spleen and other organs stained with our colloid are presented as examples. These micrographs confirm that the glomerular podocyte end-foot surface facing the Bowman's capsular space is strongly negative-charged. They also show that almost all lymphoid cells around the arteries in the splenic white pulp and thymic cortex contain strongly negative-charged nuclei and that the distal convoluted and collecting urinary tubules are more negative-charged than the proximal convoluted tubules.

Animals↗