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Biomedical subjects

H Inomata

Publications and source records attributed to H Inomata.

At least 163 records · Page 9Linked to original sources
PubMed1988

Lipofuscin granules in human photoreceptor cells.

Twenty-four human retinas were structurally examined in order to study the degradative pathway in inner segment turnover. Lipofuscin granules were found in myoids of photoreceptor inner segments. Cone lipofuscin granules exhibited autofluorescence, in ultraviolet light. Both the cone lipofuscin granules (-1.6 micron) and the rod ones (-0.6 micron) were membrane-limited inclusions comprising different contents. Various vacuoles related to autophagy were found in the myoids of rods and cones. Acid phosphatase activity was demonstrated in lipofuscin granules of the rods and cones, as well as adjacent various vacuoles. A survey of the cone lipofuscin granules in the semithin Epon sections revealed that more than one-half of the eyes from humans over 30 years of age contained cone lipofuscin granules, whereas eyes from those under 30 years of age did not. These results strongly suggest that lipofuscin granules represent an accumulation of residual bodies of autophagy in the photoreceptor inner segments.

Acid Phosphatase↗
PubMed1987

Projection from the pretectal nuclei to the dorsal lateral geniculate nucleus in the cat: a wheat germ agglutinin-horseradish peroxidase study.

To study the projection from the pretectum to the dorsal lateral geniculate nucleus (LGNd) in the cat, we used anterograde and retrograde transport of wheat germ agglutinin-horseradish peroxidase (WGA-HRP). Special attention was directed to the retinotopic maps of the pretectum and LGNd. Multiple restricted injections were made into different parts of the pretectum or LGNd. The pretectogeniculate pathway terminates mostly in the medial interlaminar nucleus (MIN) and layers A and A1, and to some extent in the lamina C within the ipsilateral LGNd. The lateral part of the nucleus of the optic tract (NTO) receives afferents from the superior retina, and the medial part of NTO and posterior pretectal nucleus (NPP) receives afferents from the inferior retina. There is no topographic organization in the retinal projection to the olivary pretectal nucleus (NOL). The lateral part of NTO projects ipsilaterally to the rostral portion of LGNd, which receives afferents from the superior retina. The medial part of NTO projects ipsilaterally to the caudal portion of LGNd, which receives afferents from the inferior retina. The NOL projects to all laminar parts of LGNd, ipsilaterally. The NPP projects largely to the ipsilateral MIN, which receives afferents from the pericentral and peripheral retina. These results suggest that similar parts of the retinotopic maps present in the pretectum and LGNd are connected.

Animals↗
PubMed1987

Alteration of microfibrils in the conjunctiva of patients with exfoliation syndrome.

We electron-microscopically studied 15 specimens of upper limbal conjunctiva obtained from 14 patients with exfoliation syndrome and clinical evidence of glaucoma. Of 15 specimens, four (three patients) contained exfoliation materials in the stroma of the conjunctiva. These exfoliation materials of immature, intermediate, and mature forms were composed of abnormal microfibrils lying adjacent to the fibroblasts and located in close proximity to the elastic and collagen fibers. These observations suggest a sequence of events by which microfibrils develop into exfoliation materials.

Aged↗
PubMed1987

Immunohistochemistry of retinoblastomas.

Immunohistochemical stains using neuronal and glial marker proteins were applied to retinoblastomas tissues from 14 children. Among the neurofilament triplet proteins, NF68Kd positive cells were observed in 12. Few NF160Kd positive cells were noted in 2, and NF210Kd positive cells were not detected. The positive ratio of NF68Kd and gamma-enolase seems to relate to the Flexner-Wintersteiner rosettes. Gamma-enolase positive cells were observed in 13. The distribution in tumor tissues was broader than that of NF68Kd positive cells. The immunoreactivities of NF68Kd were in parallel with those of gamma-enolase. Few GFAP positive cells were present around blood vessels, while S-100 protein and MBP positive cells were never observed. Our results indicate that retinoblastoma possesses predominantly neuronal properties, albeit in an immature form.

Child↗
PubMed1987

Histological study on transient ocular hypertension after laser iridotomy in rabbits.

We performed argon-laser iridotomy on pigmented rabbits and examined histologically the tissue of the anterior chamber angle, the iris, and the ciliary body. After laser iridotomy, 9/10 eyes showed an elevation in transient intraocular pressure. Deposits of blood plasma with fibrin were observed in the tissue of the circumferential anterior chamber angle from eyes enucleated at a period of high intraocular pressure. In the eyes in which ocular pressures returned to the baseline, the quantity of blood plasma was small. In the laser-irradiated iris and iris processes, cells constructing the vessel wall were degenerated, and blood plasma and fibrin exuded. In and around the ciliary body, fibrin was not demonstrated. These observations suggest that argon-laser irradiation to the iris leads to a breakdown of the blood-aqueous barrier mainly in the laser-treated iris, and that deposition of blood plasma with fibrin in the anterior chamber angle tissue may cause transient intraocular pressure elevations after laser iridotomy in rabbits.

Animals↗
PubMed1987

Ultrastructure of sheathed vessels in the retina from patients with various diseases.

Retinal sheathed vessels from five patients with various vascular diseases were examined by light and electron microscopy. All of these vessels were characterized by a marked increase and disarrangement of collagen fibrils in the media and adventitia. Cytoplasmic processes of glial cells had invaded the adventitia in sheathed vessels and even in unsheathed ones. Thickening and multilamination of the basal laminae were observed in both the sheathed and unsheathed vessels. The lumens of most sheathed vessels were still patent, and the blood cells and endothelial cells of these vessels appeared to be intact. We found no essential differences in the ultrastructure of these vessels in the five patients with various vascular diseases. It is concluded that the increase and disarrangement of collagen fibrils may be mainly related to the ophthalmoscopic appearance of the sheathing and that other factors seem to be of lesser significance.

Adult↗
PubMed1987

Monitoring treatment of congenital hypothyroidism by highly sensitive immunoradiometric assay for thyroid stimulating hormone.

To assess the clinical value of a sensitive immunoradiometric assay for TSH (IRMA-TSH), serum IRMA-TSH levels were compared with those of a radioimmunoassay (RIA-TSH) in twenty-eight patients with congenital hypothyroidism. Among 144 samples taken from them, 44 samples showed undetectable RIA-TSH, while only 10 samples were undetectable by IRMA-TSH. In two patients prospectively followed, RIA-TSH levels were undetectable when serum T3 and T4 were normal. IRMA-TSH levels, however, were detectable when serum T4 levels were elevated or normal. The basal RIA- and IRMA-TSH levels in 4 groups (22 patients) were compared and classified according to the TSH response to TRH. The RIA-TSH levels were undetectable in any in group 1 (n = 7; absent response) or group 2 (n = 5; low response). At the same time, IRMA-TSH levels were undetectable in only three patients in group 1. In group 3 (n = 16; normal response), RIA-TSH levels were undetectable in three, whereas IRMA-TSH levels were detectable in all. The IRMA- and RIA-TSH levels rose in all in group 4 (n = 15; exaggerated response). These results suggest that the serum basal IRMA-TSH levels indicate the responsiveness of TSH to TRH more accurately than basal serum RIA-TSH levels. Therefore, it was concluded that IRMA-TSH may obviate the need for a TRH test and simplify the evaluation of adequate dosage in patients with congenital hypothyroidism during thyroxine treatment.

Child↗
PubMed1986

Formation of drusen in the human eye.

Light and electron microscopy of drusen formation in the human eye showed yellow-white spots in the fundus with two morphologic patterns: that of typical drusen and a nodular accumulation of cellular components beneath the retinal pigment epithelial cells. By electron microscopy, the progression of drusen formation could be classified into four stages. Stage I showed budding or evagination of retinal pigment epithelial cells into the subpigment epithelial space. This evaginated portion was connected to the retinal pigment epithelial cell cytoplasm and was surrounded by its basement membrane. In Stage II the evaginated portion of the cell was completely separate from the cytoplasm of its parent retinal pigment epithelial cell. In Stage III, the evaginated portion showed degeneration and disintegration. Finally, in Stage IV, an accumulation of vesicular, granular, tubular, and linear material was seen free within the nodular space beneath the retinal pigment epithelial cell.

Aged↗
PubMed1986

Immunohistochemical evidence of the origin of human corneal endothelial cells and keratocytes.

Human corneal endothelial cells and keratocytes were immunohistochemically examined using antisera against neuronal tissue antigens, namely, S-100 protein and neuron-specific enolase (NSE), and intermediate filaments such as vimentin, neurofilament, and glial fibrillary acidic protein (GFAP). The corneal endothelium and keratocytes showed a positive immunoreaction to neuron-specific enolase and S-100 protein antisera, and these cells were also stained with antiserum against vimentin, a main intermediate filament of mesenchymal cells. These immunohistochemical findings provide additional evidence that the corneal endothelium and keratocytes originate from neural crest cells and then differentiate into mesenchymal cells.

Cornea↗
PubMed1986

Relationship between potency of blocking type thyrotropin-binding inhibitor immunoglobulin in three women with primary myxedema and thyroid function of their neonates.

Three neonates born to three mothers with primary myxedema who have thyrotropin-binding inhibitor immunoglobulin (TBII) were continually examined after birth. One neonate showed a high TSH level in mass-screening for congenital hypothyroidism and developed transient hypothyroidism. Her TBII disappeared at 114 days of age, and she remained euthyroid after discontinuation of thyroxin replacement at 146 days of age. The other two neonates were euthyroid, though they had positive TBII. In three mothers, the doses of IgGs that inhibited 125I-TSH binding to the level of 50% were compared. The potency of IgG from the mother whose neonate developed hypothyroidism was stronger than that of IgG from the other two mothers. And the elevation of cAMP induced by bovine TSH in suspension culture with porcine thyroid follicles was significantly reduced in the presence of IgG from the three mothers when compared with normal IgG. The thyroid-stimulation blocking activity was more potent in the mother whose neonate developed hypothyroidism than in the other two mothers. This study suggests that the thyroid function of neonates born to primary myxedema with blocking type TBII is influenced by the potency of TSH-binding inhibitor and thyroid-stimulation blocking activity of the mother.

Autoantibodies↗
PubMed1986

Relation between superficial capillaries and foveal structures in the human retina.

When examining semithin Epon sections of human retinas, it became evident that superficial capillaries showed four different positions, according to the thickness of the ganglion cell layer. For the clear view of the distribution of the position of superficial capillaries, the intrafoveal region was subdivided into four zones, based on the thickness of the ganglion cell layer; the foveola and the A-, B-, and C-zone. The foveola has no ganglion cell layer, and the A-zone has a ganglion cell layer thinner than 15 microns. These regions lack superficial capillaries. In the B-zone, the ganglion cell layer is 15-45 microns thick, and here the superficial capillaries lie in the outer boundary of the ganglion cell layer. The C-zone and parafovea have a ganglion cell layer thicker than 45 microns, and superficial capillaries are present within the ganglion cell layer. The perifovea has a ganglion cell layer 15-45 microns thick. In the temporal perifovea, where the nerve fiber layer is not so distinct, superficial capillaries are located on the outer boundary of the ganglion cell layer. In the other portion of the perifovea, superficial capillaries lie in the inner boundary of the ganglion cell layer. Out of the perifovea, where the ganglion cell layer is thinner than 15 microns, most of superficial capillaries touch both boundaries of the ganglion cell layer. Major retinal vessels touch the ganglion cell layer and lie in the similar position to that of superficial capillaries.

Adult↗
PubMed1985

Decrease in membrane conductance induced by noradrenaline in the smooth muscle of guinea-pig vas deferens.

The electrical response of the smooth muscle of guinea-pig vas deferens to exogenously applied noradrenaline (NA) was examined using the double sucrose-gap method. NA evoked a depolarization of the smooth muscle membrane which was associated with an increase in the size of electrotonic potentials. A conditioning depolarization of the membrane induced by current application enhanced the size of NA-induced depolarization, whereas a conditioning hyperpolarization reduced it. When a conditioning hyperpolarization of 25 mV in magnitude was applied, the direction of potential change induced by NA was reversed. These results are discussed with respect to the ionic mechanism of the electrical event in response to NA in this tissue.

Adenosine Triphosphate↗
PubMed1985

Evidence for an increase in membrane conductance during adenosine triphosphate-induced depolarization in the guinea-pig vas deferens.

The effects of exogenously applied adenosine triphosphate (ATP) on the smooth muscle of guinea-pig vas deferens were studied with the double sucrose-gap method. ATP evoked a membrane depolarization which was associated with a decrease in the size of electrotonic potentials. Conditioning hyperpolarization induced by current application caused an increase in the magnitude of the ATP-induced depolarization; the larger the conditioning hyperpolarization, the greater the ATP-induced depolarization. These results are discussed with respect to the ionic mechanism of the electrical event in response to ATP in this tissue.

Adenosine Triphosphate↗
PubMed1985

Adrenergic excitatory and cholinergic inhibitory innervations in the human iris dilator.

To investigate the pattern of innervation in the human iris dilator muscle, effects of field stimulation on the isometric tension of dilator muscle were investigated in vitro. Throughout the experiments, spontaneous contractions did not occur. Application of repetitive field stimulations evoked biphasic mechanical responses (i.e. an initial phasic contraction followed by long lasting relaxation) of the isolated human iris dilator. These mechanical responses were abolished by 10(-7) M tetrodotoxin (a nerve poison), thereby indicating that the mechanical responses were neurogenic. Furthermore, the initial phasic contractions and following muscle relaxation were selectively blocked by phentolamine (10(-5) M) and atropine (10(-5) M), respectively. The degree of the muscle relaxation to that of contraction was much larger than that assumed by other investigators who used tissues from different species. The present results indicate that the human iris dilator muscle is innervated by adrenergic excitatory and cholinergic inhibitory nerves, and that cholinergic inhibitory innervations in this muscle may support the cholinergic miosis in the iris sphincter muscle.

Biomechanical Phenomena↗