Search PubMed⌕ Search

Biomedical subjects

Y Taniguchi

Publications and source records attributed to Y Taniguchi.

At least 523 records · Page 29Linked to original sources
PubMed1984

Electron microscopic immunocytochemistry by the protein A-gold method of two types of rat anterior pituitary ACTH cells.

Immunocytochemical detection of ACTH using the protein A-gold method was performed in the adult male rat anterior pituitary gland after simple glutaraldehyde fixation and double fixation with glutaraldehyde and osmium tetroxide. Immunoreactive ACTH cells of the rat anterior pituitary can be classified into two groups: typical and atypical ACTH cells. The typical ACTH cells are small stellate cells extending slender processes, and contain secretory granules aligned in a single row along the cell surface. The atypical ACTH cells are rather fat, polygonal or oval cells with a few stout processes. Secretory granules are very numerous and fill the entire cytoplasm, and are not limited to the cell periphery. The latter cell's granules vary widely in electron density after glutaraldehyde and osmium. Among these variable secretory granules, the dense ones are strongly labeled with ACTH-reactive colloidal gold particles, but less dense ones are not. The typical ACTH cells reported here correspond to the Type II ACTH cells, while the atypical ones are the Type I ACTH cells previously reported. The results of protein A-gold immunocytochemistry of ACTH favor the view that two types of ACTH cells are present in the rat anterior pituitary. An intermediate type of ACTH cells was also observed, suggesting a transition between the above mentioned two types of ACTH producers.

Adrenocorticotropic Hormone↗
PubMed1984

Immunohistochemical evidence against the coexistence of a corticotropin-releasing factor and oxytocin or vasopressin in the rat paraventricular nucleus.

A corticotropin-releasing factor (CRF), oxytocin and arginine-vasopressin were localized immunohistochemically in the paraventricular nucleus of colchicine-treated male rats. Small CRF-containing neurons were distributed in the parvocellular region. Some magnocellular neurons were also immuno-stained with anti-CRF serum, but after preabsorption of the antiserum with pure synthetic CRF, the staining of these magnocellular neurons was unaffected, which suggests that this CRF-positive reaction was non-specific. By comparing the distribution of CRF and oxytocin or vasopressin on serial 5 micron cryostat sections, it was revealed that CRF and oxytocin or CRF and vasopressin do not coexist in the same neuron.

Animals↗
PubMed1984

Development of early lesions of microangiopathy in chronically diabetic monkeys.

A chronic diabetic state was produced in Macaca fuscatus , and these diabetic monkeys were kept without insulin treatment for up to 25 mo. The metabolic derangements were characterized by hyperglycemia, insulinopenia, hyperglucagonemia, ketonemia, and hyperlipidemia. Significant thickening of the capillary basement membrane of the gastrocnemius muscle was observed in the chronically diabetic monkeys, and became obvious in the course of diabetic state; 732 +/- 35 A in controls, 750 +/- 58 A in diabetic monkeys with duration of 4 mo, and 1165 +/- 112 A in those with duration of more than 11 mo. In addition to duration of the diabetic state, severity of hyperglycemia is also thought to play an important role in the capillary basement membrane thickening judging from the fact that diabetic monkeys with constant hyperglycemia showed a greater membrane thickening. Ultrastructural alterations, such as significant thickening of glomerular basement membrane and increase of mesangial matrix, were observed in kidney as well. These results indicate that diabetic microangiopathy has been produced by metabolic derangements characterized by chronic hyperglycemia, insulinopenia, and hyperlipidemia.

Animals↗
PubMed1984

[Mechanism of inhibition of hypothalamic pituitary-ovarian function in streptozotocin-diabetic mature female rats].

In order to clarify the mechanism of the failure of reproductive function in diabetic rats, the hypothalamic pituitary-ovarian function in streptozotocin-induced diabetic mature female rats was investigated. Estrous cycle patterns were disturbed in diabetic rats and these rats showed constant diestrus. In diabetic rats no preovulatory LH or FSH-surge were observed on presumed proestrus, and the number of ovulated ova and the weights of ovary and uterus were significantly less than those seen in control rats on presumed estrus. The response of the pituitary gland to LH-RH in diabetic rats and diabetic castrated rats was not significantly different from that in control rats on diestrous day and castrated control rats, respectively. However, the response of the hypothalamic-pituitary axis to steroidal feedback in diabetic castrated rats was significantly less than that in castrated control rats. The number of ovulated ova and ovarian growth induced by hCG in diabetic rats were also significantly lower than those in control rats. These results indicate that the impaired site in streptozotocin diabetic rats is not the pituitary gland, but the ovary and hypothalamic-pituitary function.

Animals↗
PubMed1983

Focal hyperplasia of intracytoplasmic filaments in the canine parathyroid gland treated with nalidixic acid.

Focal hyperplasia of intracytoplasmic filaments of 100A in diameter was observed within chief cells of the parathyroid gland in dogs treated with nalidixic acid. The structure, as a rule, was located in the neighborhood of the nucleus and no other cell organelles were detected within it. Its size had a wide spectrum from a small part of the cytoplasm to as large as half a cell. Golgi apparatus and rough endoplasmic reticulum in the involved cells had a tendency to atrophy. These cells occasionally contained less secretory granules. Lipid droplets are diffusely increased. The pathogenesis and significance of the present intracytoplasmic filaments remain to be determined. However, as lipid deposition, atrophy of Golgi apparatus, poorly developed rough endoplasmic reticulum occur in a hypofunctional or degenerative state, it might be possible that filamentous hyperplasia is closely associated with that state.

Animals↗
PubMed1983

A new protocol for individualized hMG therapy by estrogen priming and cervical mucus monitoring.

A new protocol of estrogen-priming and cervical mucus monitoring for individualized hMG therapy was devised. Prior to treatment, the amount of cervical mucus ("a" mm3) should be determined. Then the peak value ("b" mm3) on the amount of cervical mucus resulting from the exogenous 2-day injection of 1 mg of estradiol benzoate is confirmed. After a decrease of the amount of cervical mucus is noted, daily dose of 225(1 - a/b) IU of hMG is administered until the amount of cervical mucus reaches or exceeds the "b" value. hCG is given 36 hours later than the last previous injection of hMG. This new individualized hMG therapy induced 51 ovulations (69.9%), 9 pregnancies (17.6%), and no multiple pregnancies (0%) out of 73 treated anovulatory cycles. This new protocol appears promising for prevention of multiple pregnancy due to hMG therapy, perhaps based on the mechanism of estrogen priming and individualization of both daily dose and duration of hMG administration.

Anovulation↗
PubMed1983

Choroidal neovascularization in long-standing case of Vogt-Koyanagi-Harada disease.

The eyes in a case of Vogt-Koyanagi-Harada disease (VKH) with long-standing uveitis for 26 years after the onset were studied histopathologically. It was found that typical granulomatous inflammation was persistent in the uveal tract and the choroidal neovascularization occurred in the peripheral fundus accompanied by proliferation of the retinal pigment epithelial cells (RPE). Some of the new vessels under the pigment epithelium extended into the vitreous. It was concluded that the ocular inflammation of VKH was essentially granulomatous even in this long-standing case. Disappearance of choroidal melanocytes, existence of epithelioid cells containing pigment granules, and accumulation of lymphocytes and plasma cells in the lesion indicated that the inflammation was an autoimmune reaction against uveal melanocytes, although the trigger initiating the disease remains unknown. It was further concluded that the peripheral fundus as well as the peripapillary and macular areas was a predilected site for choroidal neovascularization in chronic uveitis. The choroidal neovascularization may develop in such a way that the uveal inflammation damages the Bruch's membrane and choriocapillaris and consequently causes retinal ischemia, thus stimulating the endothelium of the choriocapillaris and the overlying RPE to proliferate. There is a close relation between choroidal neovascularization and proliferation of RPE. Choroidal neovascularization may cause reactive proliferation of the RPE and vice versa.

Choroid↗
PubMed1983

[Effects of Hachimijiogan on hypothalamo-pituitary-testicular system].

Effects of Kampo (Chinese) drugs on hypothalamo-pituitary-gonadal system were investigated in immature male rats of Holtzman strain. Hachimijiogan(H), its components and Ninjin(N) were administered orally to the animals for 28 days, and the weight of the various organs, pituitary content of FSH, LH and PRL, and serum concentration of FSH, LH, PRL and testosterone were measured. H caused a significant increase in the weight of seminal vesicles while H, Sanyaku(S) and N caused a significant increase in the weight of the prostate, respectively. The pituitary content of FSH was significantly increased by H and S, respectively, while the testosterone concentration was significantly decreased by Jio, S and N, respectively. No increase in the weight of the prostate or seminal vesicles followed the administration of H, S and N to orchiectomied immature rats. This result clearly shows that these three drugs have no androgenic activity. After the administration of H to immature male rats, the character of dihydrotestosterone(DHT) receptor was studied by the DCC method. The number of binding sites of DHT receptor was significantly increased by 32% (p less than 0.001) by H. These results demonstrate that H has a stimulatory effect on androgen target organs through the increase in androgen receptor in these organs.

Animals↗
PubMed1983

Distributions of 35S-sulfate and 3H-glucosamine in the angular region of the hamster: light and electron microscopic autoradiography.

The distribution of 35S-sulfate and 3H-glucosamine in the angular region of the hamster was studied by light and electron microscopic autoradiography following intraperitoneal injection of these compounds to hamsters. Exposed silver grains of 35S-sulfate were concentrated in the trabecular meshwork, sclera, and cornea, and grains of 3H-glucosamine were localized in the trabecular region. The radioactivity of both isotopes was observed in the Golgi apparatuses of the endothelial cells of the angular aqueous plexus and the trabecular meshwork. The grains were noted over the entire cytoplasm, except for the nucleus, and then were incorporated into the amorphous substance and collagen fibers in the region adjacent to the angular aqueous sinus. These results suggest that endothelial cells in the angular region synthesize and secrete the sulfated glycosaminoglycans and hyaluronic acid.

Animals↗
PubMed1983

Localization fo 3H-glucosamine and 35S-sulfate in the hamster retina--light and electron microscopic autoradiography.

The localization of 3H-glucosamine and 35S-sulfate in the hamster retina was studied by light and electron microscopic autoradiography. Exposed silver grains were concentrated in the nerve fiber, inner plexiform, outer plexiform and inner segment layers. The heaviest labeling was observed over the inner segment layer in the glucosamine experiment and over the nerve fiber layers in the sulfate experiment. Specimens from 12- and 16-day-old hamsters showed slightly heavier labeling than did those from adult animals. In the electron microscopic autoradiography using 3H-glucosamine, grains were initially associated with the retinal pigment epithelium, the inner segment and the Müller cell and were subsequently displaced into the spaces between the retinal pigment epithelium and the other segment and into the nerve fiber layers. The labelled sulfates in the electron microscopic autoradiography were seen in the nerve fiber, plexiform and photoreceptor layers. These data indicate that glycosaminoglycans may be synthesized in the retinal pigment epithelium, the inner segment and the Müller cell.

Animals↗
PubMed1983

Electron microscopic study of uveal circulatory disturbance in experimental diabetic rats--intraluminal changes of uveal vessels.

Intraluminal changes of uveal vessels in streptozotocin--diabetic rats, maintained for 1-12 months, were studied electron microscopically. In diabetic rats maintained for 10-12 months, microthrombus formation was observed in the various sized choroidal, ciliary and iridial vessels. The microthrombi were mainly composed of fibrin strands and platelets and there was no definite evidence of detachment or loss of endothelial cells. This microthrombus formation may play an important role in the development of diabetic uveal circulatory disturbance.

Animals↗