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Biomedical subjects

Y Isayama

Publications and source records attributed to Y Isayama.

At least 37 records · Page 2Linked to original sources
PubMed1987

Evidence for sialyl glycoconjugates as receptors for Bordetella bronchiseptica on swine nasal mucosa.

The nature of the receptors for Bordetella bronchiseptica was investigated by using the in vitro adherence assay system. The results indicated that sialyl glycoconjugates acted as receptors on swine nasal mucosa. These results were obtained by two independent approaches: inhibition of epithelial cell adherence with sialic acid-containing compounds but not with compounds lacking sialic acid residues and loss of adherence after treatment of epithelial cells with periodate or neuraminidase. B. bronchiseptica seems to have strong affinity for mucin. This may help the bacterium to colonize the mucosal surfaces of the swine nasal cavity.

Animals↗
PubMed1987

Effect of antigenic modulation and phase variation on adherence of Bordetella bronchiseptica to porcine nasal epithelial cells.

In parallel with bacterial density, Bordetella bronchiseptica phase-I, X-mode cells adhered well to porcine nasal epithelial cells, whereas C-mode cells and variant cells in phases II, III, and rough adhered feebly. Cell surface components lost, on transition from X to C mode or from phase I to degraded phases, may confer much of the organism's adherence ability.

Agglutination↗
PubMed1986

Bordetella bronchiseptica phase variation induced by crystal violet.

A method for effective induction of phase variation in Bordetella bronchiseptica by treatment with crystal violet (CV) is presented. When grown in CV-broth, phase I cells dissociated into three serial phases. Appearance of variant cells was observed simultaneously with the beginning of cell multiplication. The maximum effect of CV was obtained at a concentration of 8 micrograms/ml, when the proportion of variants in the population reached 100%. The main factors which affected phase variation were concentration of CV, culture age, and temperature of treatment. The phase variants obtained were phenotypically stable upon serial passages on Bordet-Gengou agar plates. By this treatment, no reversion of phase descendants to former phases was observed.

Agglutination Tests↗
PubMed1984

Visual fatigue phenomenon and prescribing tinted lenses in patients with optic neuritis.

The fatigue phenomenon of grating visual acuity was examined in 36 patients with optic nerve disorders by means of a laser interferometric acuity device. The phenomenon was found in 6 of 36 cases even under a luminance corresponding to the Japanese standards of office illumination. This fact indicated that the patients suffered visual fatigue in their everyday vision. After they were prescribed tinted lenses to eliminate the fatigue, the patients had comfortable sustained vision in their daily work.

Adult↗
PubMed1984

Calcium ion and phospholipid-dependent protein kinase in rod outer segment.

The protein kinase in a suspension of bovine rod outer segment was activated by the calcium ion. After the enzyme was extracted from the rod outer segment, the enzymatic activity required not only the calcium ion but also a membrane-associated factor for full activity. This factor resisted proteolysis and was extractable with a 2:1 mixture of chloroform/methanol. The factor could be replaced by the phospholipid fraction prepared from the ghosts of erythrocytes. Calcium ion and phospholipid-dependent protein kinase was partially purified by DEAE-Cellulose and Sephadex G-150 column chromatography. The purified protein kinase showed the molecular weight of 8.7 X 10(4) and a sedimentation coefficient of 5.1 S. Among phospholipids, phosphatidylserine and phosphatidylinositol were the most effective as cofactor. Other phospholipids such as phosphatidic acid, diphosphatidylglycerol and phosphatidylethanolamine were less effective. Phosphatidylcholine and sphingomyelin were inactive. Calcium was the most potent of all divalent cations examined for activation of the protein kinase, and full enzymatic activity was obtained at 4 X 10(-4) M. Strontium was 9% as potent as calcium, but other divalent cations such as barium, zinc, cobalt and magnesium had no effect.

Animals↗
PubMed1984

Unusual case of melanocytoma in optic disk.

An unusual case of melanocytoma in the optic disk was reported. At the initial examination, unilateral papilledema and irregular concentric contraction of the visual field with fair vision were observed. In the follow-up study, central retinal artery occlusion occurred and vision deteriorated to blindness. Subsequently, a darkly pigmented lesion appeared and enlarged slowly during the period of 14 years. The pathogenesis of visual disturbance caused by the melanocytoma was discussed.

Adult↗
PubMed1983

Retinoblastoma in a 26-year-old adult.

Retinoblastoma in a 26-year-old woman is reported clinicopathologically, and the difficulties in this clinical diagnosis are presented. Clinical and morphologic findings of this case suggest that rare embryonal retinal cells can persist and be subject to late malignant transformation.

Adult↗
PubMed1983

Serogrouping of Rhodococcus equi.

The serological relationships among 27 isolates of Rhodococcus equi selected from a total of 1,195 isolates were investigated by cross-agglutination and absorption tests. The presence of capsular material was demonstrated in all the 27 isolates by electron microscopic observation. Antisera were prepared by employing formalized antigen of each isolate. In the cross-agglutination test with formalized antigen, 13 antisera reacted with homologous antigens alone, but the remaining 14 antisera reacted not only with homologous antigens but also with one to four heterologous antigens. When these 14 antisera possessing heterologous agglutinins were absorbed with each of the cross-reacting antigens, 14 specific antisera were obtained. The cross-agglutination test with these 27 antisera proved the 27 strains examined to be serologically distinct from one another. These strains were designated serogroups 1 to 27. Thus the same number of grouping antisera were prepared. The distribution of each serogroup among the 1,195 isolates and 15 reference strains was investigated by the slide agglutination test. All the strains were found to be groupable. Most of them belonged to serogroups 1 to 4, 7 to 9, 11, 14, and 15. Of the serogroups designated, 4, 16, 2, 12, 21, 1, and 9 were identical with Prescott's serovars 1, 2, 3, 4, 5, 6, and 7, respectively.

Agglutination Tests↗
PubMed1983

In vitro susceptibility of Haemophilus somnus to 33 antimicrobial agents.

Minimal inhibitory concentrations of 33 antimicrobial agents for Haemophilus somnus were determined by the agar dilution method. The tested H. somnus strains were highly susceptible to penicillin G, ampicillin, colistin, and novobiocin. They were not susceptible to spiramicin and sulfadimethoxine, and streptomycin-resistant strains were found.

Anti-Bacterial Agents↗
PubMed1983

Posterior ischemic optic neuropathy. I. Blood supply of the optic nerve.

The blood supply of the posterior optic nerve was investigated in 10 monkeys after an injection of synthetic resin into the carotid arteries. The posterior intraorbital and intracanalicular optic nerves were supplied by a centripetal vascular system, formed by the pial vessels arising from the first branches of the ophthalmic artery. Superior and inferior vascular semicircles were detected in the intracanalicular optic nerve. The intracranial optic nerve was supplied by branches of the internal carotid artery, anterior cerebral artery and/or anterior communicating artery, and ophthalmic artery.

Animals↗
PubMed1983

Posterior ischemic optic neuropathy. II. Histopathology of the idiopathic form.

The optic nerve and chiasm, obtained at autopsy, from 53 cases with clinical histories of cerebrovascular disturbances were histopathologically investigated, and ischemic changes in the posterior portion of the optic nerve were revealed in 12 cases. The progress of posterior ischemic optic neuropathy might be divided into necrotic, liquefactive and scar stages. The lesions were located in the transverse, peripheral, altitudinal and axial areas of the optic nerve. Occlusive changes of the vascular lumina due to atherosclerosis, arteriolosclerosis, capillosclerosis and emboli were demonstrated in association with the ischemic changes in the optic nerve parenchyma.

Adult↗
PubMed1983

Posterior ischemic optic neuropathy. III. Clinical diagnosis.

14 cases of posterior ischemic optic neuropathy (PION) were clinically analyzed, in whom we excluded known etiologies of optic nerve disturbances and confirmed the decreased blood supply to the posterior portion of the optic nerve. On the basis of our clinical findings, we have proposed the following criteria for the diagnosis of idiopathic PION: (1) sudden onset of unilateral visual disturbance in older patients; (2) normal optic disc, subsequently developing simple optic atrophy; (3) hypertensive and arteriosclerotic changes in the retinal vessels; (4) varying degrees of impaired vision, variable visual field defects; (5) associated systemic disease such as hypertension, diabetes mellitus, hyperlipemia, hypotension, etc.; (6) exclusion of other demonstrable causes of optic nerve disturbances, and (7) confirmation of abnormal hemodynamics in the posterior portion of the optic nerve by carotid angiography, ophthalmodynamography, ophthalmodynamometry and fluorescein fundus angiography.

Adult↗
PubMed1983

Cardiac beat-to-beat variation as an indicator of neuropathy and the frequency of its abnormality in diabetes mellitus.

The cardiac beat-to-beat variation and the maximum constriction velocity and acceleration of the pupillary light reflex have been considered indices of parasympathetic neuropathy. The abnormality of these indices was evaluated in 191 non-diabetics and 151 diabetics. The cardiac beat-to-beat variation decreased gradually with age in non-diabetics as well as diabetics. It was small in diabetics compared to non-diabetics in corresponding age group between 10 and 59 years. In diabetics it was still smaller in the presence of peripheral neuropathy than in its absence. The overall prevalence of this abnormality was 30.1% in diabetics but only 3.0% in non-diabetics. In diabetics it rose to 40.0, 42.6 and 52.2% in the presence of motor, sensory and motor plus sensory nerve neuropathy, respectively. In 63 diabetics examined for both cardiac beat-to-beat variation and pupillary light reflex, no statistical difference was observed between the frequency of these abnormalities. These observations indicate an extremely high prevalence of abnormality in autonomic nerve function in diabetics especially in the presence of abnormality in autonomic nerve function in diabetics especially in the presence of other types of neuropathy, so that diabetics with peripheral neuropathy should be carefully examined for autonomic neuropathy and vice versa. Besides, the measurement of the cardiac beat-to-beat variation is similar in sensitivity in the detection of neuropathy to the measurement of pupillary light reflex.

Adolescent↗
PubMed1983

Chordoma.

Four cases of intracranial chordomas are reported. Intracranial chordomas initially tend to occur with sixth nerve paresis and subsequently with visual disturbance and optic disc changes. Computed tomography demonstrated an isodense mass in one case, a low-density mass in another case, and both an isodense and a partial high-density in two cases. Histopathologically, isodense areas were coincident with regions of compact tumor cells, low-density areas coincided with abundant mucinous intercellular matrices, and high-density areas were coincident with cartilaginous matrices or calcifications.

Abducens Nerve↗
PubMed1983

Craniopharyngioma--analysis of surgical procedure.

Twenty cases of craniopharyngiomas treated surgically between 1972 and 1979 have been studed neuro-ophthalmologically. The visual fields demonstrated asymetrical bitemporal hemianopsia, occasionally homonymous hemianopsia and central scotomas. The visual function was followed up for a period of one to 8 years after the operation. Improvement and retention of the visual function were observed in 88% of cases with subtotal resection and irradiation, 45% of cases with partial resection and irradiation, and 0% of totally resected cases. Histopathologically, the dense adhesion and tumor invasion in the optic chiasm were observed in autopsy cases. From the viewpoint of operative results and autopsy findings, the subtotal excision with irradiation is advocated for the treatment of craniopharyngiomas, particularly in the adult cases.

Adolescent↗