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Biomedical subjects

T Kusakabe

Publications and source records attributed to T Kusakabe.

At least 163 records · Page 9Linked to original sources
PubMed1992

Intimate apposition of the glomus and smooth muscle cells (g-s connection) in the carotid labyrinth of juvenile bullfrogs.

Intimate apposition of the glomus and smooth muscle cells (g-s connection) was found in almost all glomus cells of the carotid labyrinths in juvenile bullfrogs, Rana catesbeiana. There were three types of g-s connection: between thin processes (0.1-0.2 micron in width) without dense-cored vesicles of glomus cells and smooth muscle cells; between thick processes (1.0-1.5 microns in width) with dense-cored vesicles of glomus cells and smooth muscle cells; and between the tongue-like projections of smooth muscle cells and the flat surface of the glomus cell. In some cases, a single glomus cell made g-s connections with several smooth muscle cells. Exocytosis often occurs at the g-s connection. Afferent and efferent synapses were found on the glomus cells with g-s connections. Reciprocal synapses were also observed. On the basis of these findings, the second and third types of g-s connection are presumed to participate in vascular regulation.

Animals↗
PubMed1992

Ontogeny of substance P-, CGRP-, and VIP-containing nerve fibers in the amphibian carotid labyrinth of the bullfrog, Rana catesbeiana. An immunohistochemical study.

The ontogeny of substance P, CGRP (calcitonin gene-related peptide), and VIP (vasoactive intestinal polypeptide) containing nerve fibers in the carotid labyrinth of the bullfrog, Rana catesbeiana, was examined by the peroxidase-antiperoxidase method. The time of appearance of these three peptides was different for each. First, CGRP fibers appeared in the wall of the carotid arch and external carotid arteries, and in a thin septum between these two arteries at an early stage of larval development (stage III). At stage V, substance P immunoreactive fibers appeared, and VIP fibers were detected at the early metamorphic stage (stage XXII). Up to the completion of metamorphosis, the number of these fibers remained low. From 1 to 5 weeks after metamorphosis, substance P, CGRP, and VIP fibers increased in number to varying degrees. By 8 weeks after metamorphosis, the distribution and abundance of these fibers closely resembled those of the adults. Some CGRP and VIP immunoreactive glomus cells were found at the stages immediately before and after the completion of metamorphosis. These findings suggest that substance P, CGRP, and VIP fibers during larval development and metamorphosis may be nonfunctional, and start to participate in vascular regulation only after metamorphosis. The transient CGRP and VIP in some glomus cells may be important for the development of the labyrinth, or may take part in vascular regulation through the close apposition of the glomus and smooth muscle cells (g-s connection).

Animals↗
PubMed1992

Gene structure and multiple mRNA species of Drosophila melanogaster aldolase generating three isozymes with different enzymatic properties.

Genomic clones encoding the Drosophila aldolase gene were isolated and the organization of the gene was determined. The protein-coding region spanning nearly 3.5 kb consists of five coding exons (exon 2, 3, 4 alpha, 4 beta, and 4 gamma). The insect exon 2 corresponds to exons 2 to 7 of vertebrate aldolase genes and thus appears to have been formed by the fusion of these 6 exons into a single exon during evolution. The Drosophila aldolase gene is predicted to generate mRNAs for three isozymes (alpha-, beta-, and gamma-types) from the primary transcripts by alternative usage of the final three exons. The reverse transcriptase-PCR assay revealed the occurrence of mRNAs for the three isozymic forms at different developmental stages, and tissue-specific expression was also found to occur in adult flies. In addition to the usual type mRNA species for the alpha-, beta-, and gamma-isozymes, two novel forms of mRNAs, alpha beta- and beta gamma-type mRNAs, were detected tissue-specifically in adult flies, although their functions are unpredictable. The alpha beta-mRNA is an alpha-type mRNA in which exon 4 beta remains unspliced, while the beta gamma-mRNA is a beta-type mRNA with the exon 4 gamma remaining unspliced. Recombinant enzymes expressed in Escherichia coli were all active and exhibited different enzymatic properties.

Amino Acid Sequence↗
PubMed1992

Distribution of CGRP, substance P, VIP and somatostatin immunoreactive nerve fibers in the internal gills of larvae of the bullfrog, Rana catesbeiana.

CGRP, substance P (SP), VIP and somatostatin were demonstrated in the internal gills of larval bullfrogs using the immunohistochemical peroxidase-antiperoxidase method. Three groups of immunoreactive fibers were distinguished by their distribution area. The first group includes CGRP, SP and VIP immunoreactive fibers running in the connective tissue of the gill tufts. These fibers were associated with the capillaries. Some CGRP fibers were distributed similarly to SP fibers, and the density of VIP immunoreactive fibers was low. The second group includes CGRP, SP, VIP and somatostatin fibers distributed in the connective tissue surrounding the ceratobranchialia. The third group includes CGRP, SP and somatostatin fibers located in the branchial muscle. Their terminals appeared to be neuromuscular junctions. No immunoreactivity of leu- or met-enkephalins was found in the internal gills. From these findings, the first group of fibers is presumed to be involved in modulating ion transport of the internal gills. The second group of fibers except for the somatostatin fibers is thought to be continuations of the first group of fibers. The third group of fibers may possibly be involved in the modulation of transmissions at the neuromuscular junction. It is unclear whether somatostatin terminals are also involved in this.

Animals↗
PubMed1991

Dense granule-containing cells in the wall of the branchio-cardiac veins of a fresh water crayfish (Astacus leptodactylus).

The anatomical structure of oxygen-sensitive receptors in branchio-cardiac veins of a crayfish (Astacus leptodactylus) was studied with fluorescence and electron microscopy. Fluorescent cells were observed in the wall of a restricted part of the branchio-cardiac veins which was electrophysiologically shown to be a chemoreceptor region. Electron microscopy disclosed that they were dense granule-containing cells, and form, together with supporting cells and nerve terminals, complex structures that show gross similarities with arterial chemoreceptor structures in vertebrates.

Animals↗
PubMed1991

Localization of substance P, CGRP, VIP, neuropeptide Y, and somatostatin immunoreactive nerve fibers in the carotid labyrinths of some amphibian species.

Immunohistochemical localization of substance P (SP), CGRP, VIP, neuropeptide Y (NPY), and somatostatin (SOM) in the carotid labyrinth were compared in some species of amphibians using the peroxidase-antiperoxidase method. Immunoreactivity of SP, CGRP, VIP, and NPY was found in the nerve fibers distributed in the intervascular stroma of the carotid labyrinth. SP, CGRP, and VIP immunoreactive varicose fibers were densely distributed in the peripheral portion of the carotid labyrinth. Some SP-immunoreactive fibers were distributed similarly to CGRP-immunoreactive fibers. The density of NPY and SOM immunoreactive varicose fibers was low. No immunoreactivity of enkephalins was observed in the labyrinth. The intensities of these peptides were varied from species to species. No glomus cells showed immunoreactivity for any of the 7 peptides studied. These results suggest that the vascular regulatory function, which is one of the possible functions of the carotid labyrinth, is controlled by the peptidergic mechanisms in addition to regulation through intimate apposition of glomus and smooth muscle cells (g-s connection).

Ambystoma↗
PubMed1991

Morphogenesis of the carotid labyrinth in the bullfrog, Rana catesbeiana, during larval development and metamorphosis.

Morphogenesis of the carotid labyrinth in Rana catesbeiana during larval development and metamorphosis was studied using vascular corrosion casting and scanning electron microscopy. The carotid labyrinth was formed at the point where the carotid arch descends to the internal gills. The transformation of the appearance of the carotid labyrinth can be summarized in six phases. 1. Through the early stages of larval development (stages I-V), the slightly expanded region of the external carotid artery becomes closely connected with the carotid arch, and these two arteries are joined by small channels on their opposing faces. 2. By the last stage of foot stages (stage XVII), the expanded region becomes globular. 3. At the middle of the metamorphic stages (stage XXII), many protuberances appear on the surface of the globular expansion. 4. At stage XXIII, these form a rudimentary vascular maze. 5. At stage XXIV, this globular expansion is completely surrounded by a simple maze-like structure that resembles the carotid labyrinth in adults. The origin of the internal carotid artery is located within the vascular maze. 6. At the final stage of metamorphosis (stage XXV) the carotid labyrinth is nearly completed. The vascular ring and vascular routes found in the adult can be recognized at the proximal and distal end of the labyrinth, respectively. These findings suggest that the premetamorphic carotid labyrinth has a vascular regulatory function.

Animals↗
PubMed1991

The occurrence of melanosomes in the newt glomus cell.

Combined light and electron microscopic observations of the carotid labyrinth of the newt, Cynops pyrrhogaster, revealed the occurrence of glomus cells with melanosomes (MG cells), a finding so far unreported in the amphibian carotid labyrinth. These melanosomes, which derived from melanophores, were electron-dense and usually oval (250-700 nm in diameter). They occurred in groups enclosed by a limiting membrane, and the diameter of clusters was approximately 1.5 microns. These clusters were surrounded by a large number of dense-cored vesicles (60-100 nm in diameter), which were predominantly located in the glomus cell cytoplasm. The density of dense-cored vesicles in MG cells was higher than that in regular glomus cells (G cells).

Animals↗
PubMed1991

[Cavernous angioma of falx cerebri; case report].

A first case of cavernous angioma of falx cerebri is reported. A 62-year-old woman who had a history of intermittent headache and dizziness was admitted to our hospital. On admission she had no neurological deficit, but CT scan showed a slightly high density tumor located beneath the falx cerebri. This was markedly and homogeneously enhanced by contrast medium. MRI showed a tumor with low intensity in T1-weighted image and high intensity speckled with low intensity in T2-weighted image. Angiogram revealed a faint tumor-stain fed by the bilateral pericallosal arteries at middle arterial to late venous phases. With the tumor attached to the lower edge, the falx was totally removed through a left front-parietal craniotomy. Histologically the tumor was diagnosed as cavernous angioma and thought to have originated from the dura mater of the falx. A search in the literature revealed that only 7 cases of extracerebral cavernous angiomas excluding ones in the middle cranial fossa have been previously reported. Five of them were located at the tentorium cerebelli and two at the convexity. The MRI finding such as speckled mixed intensity may reflect the vascular lumens or their thromboses in the tumor. Angiographic finding such as faint tumor stain at middle arterial to late venous phases due to slow blood flow in the tumor are thought to be specific to intracranial cavernous angiomas. These findings are of particular importance in differentiating cavernous angiomas from meningiomas.

Aged↗
PubMed1990

Comparative studies on the vascular organization of carotid labyrinths of anurans and caudates.

The three-dimensional structures of the carotid labyrinth in five species of anurans representing four families (Rana nigromaculata, Rana catesbeiana, Bufo japonicus, Hyla arborea, and Xenopus laevis), and three species of caudates representing three families (Cynops pyrrhogaster, Hynobius nebulosus, Ambystoma mexicanum) were compared using vascular corrosion castings and scanning electron microscopy (SEM). Anuran carotid labyrinths are spherical in shape and are classified into two groups according to the origin of the external and internal carotid arteries. One group, which included Rana, Hyla, and Bufo, is characterized by the presence of a vascular ring at the proximal end and some vascular routes at the distal end of the labyrinth. The external and internal carotid arteries originate from these structures. The other group, which includes only Xenopus, is characterized by the external carotid artery opening directly from the central chamber or the common carotid artery, and by the internal carotid artery originating from within the vascular maze. The vascular maze is most complex in Xenopus, less so in Rana and Bufo, and simplest in Hyla. The carotid labyrinths in Cynops and Hynobius are oblong in shape. The fundamental organization in salamanders is similar to that in anurans. The vascular maze, however, is much simpler than in Hyla. There is no specialized swelling in Ambystoma mexicanum. The present findings suggest that most amphibian carotid labyrinths have the appropriate architecture for controlling vascular tone.

Animals↗
PubMed1989

Flow of egg white ovalbumin into the yolk sac during embryogenesis.

Western blot analyses of yolk proteins of the White Leghorn hens showed that an ovalbumin-like molecule was included in day 16 eggs but not in the ovarian follicles, and very little in newly deposited eggs. Northern hybridization, as well as in vitro translation, of poly(A)+ RNAs prepared from the yolk sac membranes of developing embryos gave no signal for ovalbumin messages. These results imply that the present ovalbumin-like protein of yolk has its origin in egg white, not being a de novo synthesis product in the yolk sac membranes.

Animals↗
PubMed1989

Substance P immunoreactivity in the vagal nerve of mice.

After horseradish peroxidase was applied to the main trunk of the mouse vagal nerve, anterogradely labeled cells in the vagal ganglia and fibers in the solitary complex, and retrogradely labeled cells in the dorsal motor nucleus and the ambiguous nucleus were observed. Most of the cells in the nodose ganglion were labeled, but only a few cells in the jugular ganglion were labeled. Heavily labeled nerve terminals and fibers were found in 3 areas in the solitary nucleus: i.e., the lateral half of the medial nucleus, the ventrolateral nucleus, and the commissural nucleus. There was only weak labeling in the dorsolateral nucleus, ventral nucleus, and intermediate nucleus. Substance P immunoreactive neurons in the vagal ganglia were found in the jugular ganglion and the dorsal part of the nodose ganglion, but not in the ventral part of the nodose ganglion. Substance P immunoreactivity in the solitary nucleus was moderate in the commissural nucleus and the intermediate nucleus, but was lacking or very weak in the lateral half of the medial nucleus, ventral nucleus, dorsolateral nucleus, and ventrolateral nucleus. We conclude that most substance P containing fibers in the main trunk of the vagal nerve project centrally to the commissural nucleus and peripherally to some of the thoracic viscera.

Animals↗
PubMed1989

[Determinations of silicon and phosphorus in rice planted in a district of high incidence of amyotrophic lateral sclerosis by neutron activation and X-ray fluorescence analyses].

Silicon and phosphorus contents in polished and unpolished rice planted in a district of high incidence of amyotrophic lateral sclerosis (ALS) have been determined by neutron activation and X-ray fluorescence methods, and compared with those from control areas. In the neutron activation analysis, beta-ray spectra of 32P produced by the 31P(n, gamma)32P reaction on polished and unpolished rice were measured with a low background beta-ray spectrometer. In the X-ray fluorescence analysis, characteristic X-rays were analyzed with a wavelength dispersive X-ray fluorescence spectrometer. Silicon contents in polished and unpolished rice from the ALS area are 42 micrograms.g-1 and 370 micrograms.g-1, respectively, and the corresponding phosphorus contents are 1,210 micrograms.g-1, and 3,370 micrograms.g-1, respectively. The data for ALS area are equal to those for the control area within standard deviation.

Amyotrophic Lateral Sclerosis↗
PubMed1987

A possible role of the glomus cell in controlling vascular tone of the carotid labyrinth of Xenopus laevis.

To clarify the physiological significance of the g-s connection (intimate apposition of the glomus cell to the smooth muscle) in the Xenopus carotid labyrinth, experiments were carried out morphologically and physiologically. Results obtained are as follows. Efferent electrical stimulation of the glossopharyngeal nerve resulted in concentrating dense-cored vesicles on the peripheral region of the glomus cell, and a decrease of vesicles as a whole. In the carotid labyrinth perfused artificially, outflow of the internal and the external carotid arteries decreased with administration of catecholamines (adrenaline, noradrenaline and dopamine). Acetylcholine reduced only the internal outflow. This response was depressed by atropine, hexamethonium and phentolamine, whereas accelerated by propranolol. Sodium cyanide reduced the internal outflow without affecting the external outflow, and its effect is depressed by phentolamine. From these results, a possibility that the glomus cell participates in controlling the blood flow in the labyrinth through the intervention of the g-s connection was discussed.

Acetylcholine↗
PubMed1985

Electrophysiological aspects of reflexogenic area in the chelonian, Geoclemmys reevesii.

Electrophysiological and anatomical experiments were performed to determine the baro- and chemoreceptive area of the turtle, Geoclemmys reevesii. The baro- and chemoreceptive sites are located in the aortic and pulmonary arches and the truncal region. The aortic arch is innervated by both the superior truncal nerve (aortic nerve) and a branch of the inferior truncal nerve arising from the ganglion trunci of the vagus. The pulmonary arch is innervated by a fine branch of the inferior truncal nerve, a branch containing mainly barosensitive and a few chemosensory fibers. On the peripheral cut end of these nerves, afferent electrical baro- and chemosensory activities were induced by NaCN and hyperoxia. Fluorescence microscopy revealed that the glomus cells are located in these regions.

Afferent Pathways↗
PubMed1985

Chemo- and baroreceptor innervation of the aortic trunk of the toad Bufo vulgaris.

In the toad Bufo vulgaris, afferent impulses were recorded from the fine branch of the vagus which terminates in the aortic trunk. Spontaneous single unit discharge was random. When the aorta was artificially perfused, units fired in response to flow change, hypoxia and hypoxia-hypercapnia of the perfusion fluid, and administration of NaCN or Ach. A few baroreceptor fibers fired synchronously with the blood pressure fluctuation. In anesthetized toads with other reflexogenic areas denervated, the intravenous administration of NaCN caused an increase in breathing and a slight elevation of blood pressure. When the nerve concerned was cut, these responses were abolished. Electrical stimulation of the nerve's central cut end brought about the same type of response as that to NaCN. Special cells closely resembling the glomus cells in the carotid labyrinth were found in the aortic wall. In amphibia, there is an aortic nerve corresponding to that of mammals, and the aorta is one of receptive areas predominantly contributing to respiratory control.

Animals↗
PubMed1984

[Glomus cell in controlling vascular tone of the carotid labyrinth (Xenopus laevis)].

To clarify the physiological significance of g-s connection (intimate apposition of the glomus cell to the smooth muscle), vascular responses of the carotid labyrinth to both catecholamines and chemoreceptor stimulants were investigated using Xenopus laevis. The results obtained were as follows. Density of dense-cored vesicles in the glomus cell was significantly varied in three different parts of the cytoplasm (N, M, P). In the part of the cytoplasm containing the nucleus (N) the density was lowest, and in the processes (P) it was highest. This bias in distribution was intensified by efferent stimulation of the glossopharyngeal nerve. In the artificially perfused labyrinth, the administration of catecholamines (adrenaline, noradrenaline and dopamine) decreased the outflow of the internal carotid artery in many cases. In a few cases it increased the internal outflow. Phentolamine changed the decrease of the outflow to an increase, while propranolol changed the increase to decrease. Acetylcholine strongly reduced the internal outflow. This response was depressed by atropine, hexamethonium and phentolamine, while intensified by propranolol. Sodium cyanide reduced the internal outflow. This effect was depressed by phentolamine. The possibility that the glomus cell participates in controlling the blood flow of the labyrinth as a result of the secretion of catecholamine through the g-s connection is discussed.

Acetylcholine↗