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Biomedical subjects

H Ninomiya

Publications and source records attributed to H Ninomiya.

At least 289 records · Page 16Linked to original sources
PubMed1988

Nicotinic acetylcholine receptors in the rat stomach: II. Alterations after vagotomy.

Nicotinic and muscarinic acetylcholine receptors were studied in the stomach of vagotomized rats, with ligand binding techniques, and with the concomitant measurement of choline acetyltransferase (ChAT). The maximum binding capacity (Bmax) of the high affinity sites of (-)-[3H]nicotine binding was significantly increased in all the regions of the stomach of subdiaphragmatically vagotomized animals while the values for the low affinity sites remained the same as those in sham-operated animals. On the other hand, [3H]quinuclidinyl benzilate binding to the stomach was unchanged after vagotomy. ChAT activity was significantly reduced in the vagotomized rats. These results suggest that surgical vagal denervation causes an increase in the density of nicotinic acetylcholine receptors presumably located on the parasympathetic ganglion cells. There is also a reduction of ChAT activity, probably due to a degenerative loss of preganglionic cholinergic neurons. Preganglionic denervation (decentralization) has little influence on the muscarinic receptors of postsynaptic effector organs.

Animals↗
PubMed1988

Decay-accelerating factor (DAF) on the blood cell membranes in patients with paroxysmal nocturnal haemoglobinuria (PNH): measurement by enzyme-linked immunosorbent assay (ELISA).

We developed a quantitative enzyme-linked immunosorbent assay (ELISA) for decay-accelerating factor (DAF) on blood cell membranes using monoclonal anti-DAF antibodies. DAF is an integral membrane protein of several blood cells. It regulates the C3 and C5 convertase of the classical and alternative pathways of complement activation. It is partially or completely deficient in the membranes of blood cells of patients with paroxysmal nocturnal haemoglobinuria (PNH). The ELISA we developed for DAF measurement indicated a reliable range of measurement from 2.25 to 11.25 ng of DAF. In particular, ELISA proved to be a technically simple method and its sensitivity was enhanced by using avidin-biotin complex. In this study, DAF levels in extracts of erythrocytes from 30 healthy donors and in extracts of PMN and platelets from 15 healthy donors were measured by ELISA. The DAF content of blood cells from eight patients with PNH and erythrocytes from 13 patients with anaemia were also measured. The DAF levels of normal erythrocytes, PMN and platelets were 3110 +/- 960, 28,000 +/- 13,900 and 3100 +/- 1370 (mean +/- SD) molecules/cell, respectively. In general, the DAF content of PNH cells was below the normal range, although it was within the normal range in some cases of PNH. The DAF levels of PNH-I and -II erythrocytes were estimated from the ratio of PNH-I, -II and -III erythrocytes. And, in four cases of PNH, the DAF levels of PNH-I erythrocytes separated by acidified serum lysis were measured by ELISA. In most cases of PNH, DAF was found to be partially deficient in PNH-I and PNH-II erythrocytes.

Adult↗
PubMed1988

Increased binding of [3H]muscimol and [3H]flunitrazepam in the rat brain under hypoxia.

We examined the effects of in vivo hypoxia (10% O2/90% N2) on the gamma-aminobutyric acid (GABA)/benzodiazepine receptors and on glutamic acid decarboxylase (GAD) activity in the rat brain. Male Wistar rats were exposed to a mixture of 10% O2 and 90% N2 in a chamber for various periods (3, 6, 12, and 24 h). The control rats were exposed to room air. The brain regions examined were the cerebral cortex, striatum, hippocampus, and cerebellum. GABA and benzodiazepine receptors were assessed using [3H]muscimol and [3H]flunitrazepam, respectively. Compared with control values, GAD activity was decreased significantly following a 6-h exposure to hypoxia in all four regions studied. On the other hand, the numbers of both [3H]muscimol and [3H]flunitrazepam binding sites were increased significantly. The increase in receptor number tended to return to control values after 24 h. Treatment of the membrane preparations with 0.05% Triton X-100 eliminated the increase in the binding capacity. These results may represent an up-regulation of postsynaptically located GABA/benzodiazepine receptors corresponding to the impaired presynaptic activity under hypoxia.

Animals↗
PubMed1988

Renal vascular changes in hydronephrosis in rats: scanning electron microscopy of resin casts of glomerular capillaries.

Vascular changes in the hydronephrotic glomeruli of rats were examined using corrosion casts, India ink injection and histological methods. In severe cases, the diameter of the glomerular capillary conglomerations decreased to 40-90 microns as a result of glomerular atrophy. The capillaries of these glomeruli also had reduced diameters, and were strangulated and torn off to varying degrees. The intact capillary network of the renal medulla was destroyed and the normal alignment of capillaries parallel to the tubules was lost. These morphological characteristics may account in part for the difficulty in glomerular capillary blood circulation.

Animals↗
PubMed1988

Chondrosarcoma of the mandible and falx cerebri in a Chinese hamster (Cricetulus griceus): report of a case.

A Chinese hamster (male, 1-month-old) was found to have a large nodular mass at the left mandible. The tumor appeared to replace the entire left mandible, extending from the third molar to the incisor. The tumor mass occupied most of the oral cavity to compress the tongue ventrally. Histologically, the neoplasm was composed of islands of chondrocytes with bizarre and enlarged nuclei which were surrounded by poorly differentiated mesenchymal cells. The tumor involved the falx cerebri to compress the frontal crest of the cerebrum. On the basis of histological features, this tumor was diagnosed as chondrosarcoma.

Animals↗
PubMed1987

Changes in plasma glucose, insulin (IRI), glucagon (IRG) and free fatty acids (FFA) following alanine loading in hyperthyroid patients.

The responses of plasma glucose, insulin (IRI), glucagon (IRG) and free fatty acids (FFA) following alanine loading (0.1 g/kg) were observed in 9 control subjects and 7 hyperthyroid patients, before and after restoration of thyroid function to normal. Despite the persistence of impaired glucose response to alanine, the blunted IRI and IRG responses in the hyperthyroid state were improved with a significant reduction in fasting IRI and IRG after treatment. Markedly increased FFA following alanine loading in hyperthyroid patients was reduced after treatment, but the FFA concentration remained greater than in the control subjects. We tentatively conclude that the impaired alpha and beta-cell responses to alanine were temporarily induced by the direct and/or indirect effects of thyroid hormone excess.

Adult↗
PubMed1987

Postnatal development of the testis in the Mongolian gerbil, Meriones unguiculatus.

The testicular development in gerbils was studied over 16-week periods starting from birth. Testicular weight and seminiferous tubule diameter increased considerably between 1 and 11 weeks of age. At 16 weeks the testicular weight was about 540 mg. Spermatogenesis commenced at about 2 weeks when mitoses first appeared in spermatogonia. Spermatozoa appeared in a few of the seminiferous tubules by 7 weeks and consistently so in all of the tubules at 10 weeks. Epididymal spermatozoa appeared first in the cauda epididymis at 10 weeks and were consistently present at 12 weeks. Formation of mature Leydig cells with a grouped perivascular arrangement appeared by 3 weeks and continuously so thereafter. From these results, it is evident that the male Mongolian gerbil is almost sexually matured by 10 to 12 weeks of age.

Animals↗