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Biomedical subjects

S Hirano

Publications and source records attributed to S Hirano.

At least 163 records · Page 9Linked to original sources
PubMed1997

Elicitor actions of N-acetylchitooligosaccharides and laminarioligosaccharides for chitinase and L-phenylalanine ammonia-lyase induction in rice suspension culture.

When a series of chitin oligosaccharides was added into a rice suspension culture, N-acetylchitohexaose, N-acetylchitopentaose, and N-acetylchitotetraose caused an increase in extracellular chitinase activity, mainly due to induction of a class III chitinase. In the case of N-acetylchitohexaose, a substantial increase in the chitinase activity was observed at a concentration higher than 0.01 micrograms/ml, and a maximum effect was reached at 1 microgram/ml. In contrast, N-acetylchitotriose, N-acetylchitobiose, N-acetyl-D-glucosamine, and chitohexaose (a chitosan oligosaccharide) were not very effective. Chitinase induction was also observed with laminarihexaose (a beta-1,3-glucan oligosaccharide), but about a 10-fold higher concentration, compared with N-acetylchitohexaose, was needed to get the maximum effect. beta-1,3-Glucanase activity was found in cells (but not in medium), and the activity was increased by neither N-acetylchitohexaose nor laminarihexaose. When cells were incubated with N-acetylchitohexaose, L-phenylalanine ammonia-lyase (PAL) activity increased promptly. A biphasic profile was obtained when a dose-dependent effect of the elicitor on the PAL induction was examined; the first phase was observed in a range from 0.01 to 1 microgram/ml and the second phase from 3 to 300 micrograms/ml. Laminarihexaose also acted as an elicitor for PAL induction.

Antineoplastic Agents↗
PubMed1997

Acute cutaneous barrier perturbation induces maturation of Langerhans' cells in hairless mice.

Perturbation of the cutaneous water permeability barrier has been shown to result in many physiological events in keratinocytes, including upregulation of proinflammatory cytokine production. However, little is known about the effect of barrier disruption on Langerhans' cells (LC). In the present study, we examined whether acute barrier perturbation by acetone treatment or tape stripping affects the phenotypes and functions of LC in male hairless mice. Both procedures resulted in a two- to five-fold increase in the expression of MHC class II antigens, B7-2 and intercellular adhesion molecule-1 on LC, whereas no significant changes were detected in levels of B7-1. Levels of intracellular interleukin-1 beta, as determined by flowcytometry, were also increased 1 h after acetone treatment or tape stripping. LC obtained from barrier-disrupted mice induced a significant increase in syngeneic and allogeneic T-cell proliferation, compared to those from saline-treated mice. These results indicate that LC play a crucial role in maintaining cutaneous homeostasis against increasing exposure to external substances resulting from barrier disruption.

Acetone↗
PubMed1997

Quantitative time-course profiles of bronchoalveolar lavage cells following intratracheal instillation of lipopolysaccharide in mice.

This report shows the quantitative time-course profiles of transpulmonary migration of polymorphonuclear leukocytes (PMN) and the adhesive interaction of alveolar macrophages to the alveolar surface in response to intratracheally (i.t.) instilled endotoxin. Groups of mice received i.t. instillation of lipopolysaccharide (LPS), and free cells in the bronchoalveolar lavage (BAL) fluid were counted. PMN remaining in the lung tissue after the BAL procedure were also enumerated following enzymatic tissue digestion. Recovery of macrophages from the alveolar space by BAL was significantly decreased at 0.5 and 2 h post i.t. instillation and returned to the control value after 5 h, suggesting that alveolar macrophages became adhesive to the alveolar wall in response to LPS. Neither BAL nor lung tissue-associated PMN were increased until 0.5 h post i.t. instillation of LPS. The lung tissue-associated PMN peaked at 2 h, while the number of BAL PMN peaked at 5 h post instillation. Furthermore, although the number of BAL PMN remained at the maximum value even at 24 h post i.t. instillation of LPS, the lung tissue-associated PMN returned to the control level at this point. These results suggest that (1) the adhesive interaction of alveolar macrophages to the alveolar surface increased rapidly (< 0.5 h), (2) accumulation of PMN in the lung occurred later than the adhesion of alveolar macrophages (0.5 to 2 h) and (3) transpulmonary infiltration of PMN was completed within 24 h following i.t. instillation of LPS.

Algorithms↗
PubMed1997

Sound-induced activation of auditory cortices in cochlear implant users with post- and prelingual deafness demonstrated by positron emission tomography.

Changes of regional cerebral blood flow (rCBF) in the auditory cortices induced by sound stimulation were examined in nine postlingually and five prelingually deaf cochlear implant (CI) users by 15O-labeled water Positron Emission Tomography, and the results were compared with those of eight normal volunteers. Speech stimulation caused significantly greater rCBF increase compared with noise stimulation in the auditory association area in normal and postlingually deaf subjects. In prelingually deaf subjects, however, speech activation of the auditory association area was much less than that found in either of the other two groups. Neuronal networks for speech sound processing in the auditory association area in postlingually deaf individuals are thought be similar to those in normal subjects, while those in prelingually deaf patients who received CI after the speech acquisition period may not develop completely.

Acoustic Stimulation↗
PubMed1997

Tinnitus remission by lidocaine demonstrated by auditory-evoked magnetoencephalogram. A preliminary report.

An auditory-evoked magnetic field was recorded before and during tinnitus remission induced by an intravenous lidocaine injection. One and 4 kHz probe tones were presented monaurally in four tinnitus patients, and the responses were recorded using a 122-channel magnetometer. Three normal volunteers were also examined as controls. In tinnitus patients, the N100 m peak became sharper, while there was no marked change except for slight reduction in amplitude in normal subjects. Tinnitus remission by lidocaine may be related to attenuation of a masking-like effect of tinnitus on the sound-evoked responses.

Aged↗
PubMed1997

Epoxyquinomicins A, B, C and D, new antibiotics from Amycolatopsis. II. Effect on type II collagen-induced arthritis in mice.

The anti-arthritic effects of epoxyquinomicins on type II collagen-induced arthritis in DBA/1J mice were examined. Prophylactic treatment with epoxyquinomicins A, B, C and D (1-4 mg/kg) had potent inhibitory effects on type II collagen-induced arthritis. In contrast to nonsteroidal anti-inflammatory drugs (NSAIDs), epoxyquinomicin C (1-30 mg/kg) had neither an anti-inflammatory effect on carrageenan-induced paw edema in rats nor an analgesic effect on acetic acid-induced writhing in mice. These results suggest that the mode of action of epoxyquinomicins is different from that of NSAIDs and that epoxyquinomicins may become useful drugs for the treatment of rheumatoid arthritis.

Actinobacteria↗
PubMed1997

[A case of far-advanced gastric cancer treated with neoadjuvant combination chemotherapy of UFT, low-dose CDDP and leucovorin, followed by subtotal gastrectomy with curative intent].

We herein present a case of a 70-year-old man with the tentative diagnosis of far-advanced gastric cancer supposed to be beyond surgical intervention. Neoadjuvant chemotherapy enabled us to perform subtotal gastrectomy with curative intent. The man was admitted to our hospital with the chief complaint of poor appetite. Because preoperative examinations revealed a mass adjacent to the portal vein and common bile duct, which was suspected to be lymphnode metastasis or gastric cancer directly invading those vital structures, 4 weeks of neoadjuvant combination chemotherapy (NACC) (CDDP 10 mg/body, day 1 through day 5/week, UFT 600 mg/body, every day, Leucovorin 15 mg/body, every day) was given with resultant curative resection of the tumor one month after completion of NACC.

Aged↗
PubMed1997

[A child showing memory disorders].

We report a girl with memory disorders. Her memory remained disturbed regardless of input or output modalities. She could recognize items and recall them randomly, but she could not recall them in the correct order. She showed memory impairment with regard to temporal context. We could clearly demonstrate this by cognitive psychological and neuropsychological tests and by analyzing the results of ordinary intelligence tests by input and output modalities. These results suggest that subjects who show memory disorders should undergo further resting to clarify the qualitative aspects of these disorders and the possibility that learning disabilities caused by memory disorders should be considered a specific type of learning disability.

Child↗
PubMed1997

[A case of congenital hypomyelination neuropathy with type I Chiari malformation and mental retardation].

A four-year old boy with congenital hypomyelination neuropathy (CHMN) had mental retardation and a tic disorder, the latter commencing at 2 years of age. The diagnosis of CHMN was confirmed by electron microscopy of his biopsied sural nerve which showed loss of large myelinated fibers, decreased density of myelinated fibers, many naked axons and atypical onion bulb formation. MR imaging showed type I Chiari malformation in the absence of clinical signs attributable to it. Auditory brainstem response (ABR) showed delayed wave I peak latency, prolonged I--III interpeak latency, broad wave II duration and normal III--V interpeak latency, suggesting abnormal peripheral and normal central myelination. The association of CHMN with mental retardation. Chiari malformation and tic disorder has never been reported, the significance of which remained unclear.

Arnold-Chiari Malformation↗
PubMed1997

[Malignant lymphoma of the testis: report of two cases].

Two cases on non-Hodgkin's malignant lymphoma (NHL) of the testis are reported. A 63-year-old man with left painless scrotal swelling underwent orchiectomy. Although prophylactic irradiation was performed under the diagnosis of seminoma, subsequent immunohistochemistry revealed NHL, large diffuse cell type (B type). He had stage IEA disease. Chemotherapy with cyclophosphamide, adriamycin vincristine and prednisolone was performed. The second case was in a 63-year old man with right painless scrotal swelling. Orchiectomy revealed NHL, diffuse medium cell type (B type). Because of tumor in the retrosternum, he had stage IIIEA disease. Chemotherapy and irradiation to the contralateral testis was performed.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Cortical speech processing mechanisms while vocalizing visually presented languages.

To elucidate cortical processing during vocalization, we used positron emission tomography to measure regional cerebral blood flow during vocalization in six Japanese subjects. During reading Japanese sentences used daily or short syllables aloud, the visual cortices, the left Heschl's gyrus, Broca's area, the primary motor area of the articulatory organs, the supplementary motor area and the cerebellum were significantly activated, compared with resting conditions. The superior temporal gyri were rarely activated. Significant activation of the cerebellum was observed by comparing cortical activity during reading sentences used daily with that during reading meaningless short syllables. These results suggest that vocalization of familiar materials is taken over by the cerebellum, rather than cortical speech areas, and without engagement of the superior temporal gyri.

Adult↗
PubMed1996

Visual projection map specified by topographic expression of transcription factors in the retina.

Topographical maps of neuronal connectivity occur in various brain regions. In the visual system of birds, retinal ganglion-cell axons from the anterior retina connect to a posterior part of the optic tectum, and posterior retinal axons connect to the anterior part, thereby establishing a point-to-point projection map. The chemoaffinity theory predicts that the orderly retinotectal projection is generated by a topographical arrangement of molecules. We report here that we have found several genes topographically expressed along the nasotemporal (anterior-posterior) axis in the embryonic chicken retina. Among these, two transcriptional regulators, belonging to the winged-helix family are expressed in a mutually exclusive manner in either the nasal or temporal part of the retina. Misexpression of each factor causes misprojection on the tectum along the rostrocaudal axis, showing that topographical expression of these transcription factors controls formation of the retinotectal map.

Alkaline Phosphatase↗
PubMed1996

Morphological analysis of the early development of the chick neural tube separated from the floor plate and notochord.

When the neural tube of avian embryos is separated from the notochord and floor plate, motoneurons in the spinal cord fail to develop. In order to investigate the factors involved in this phenomenon, cell proliferation activity and cell death were observed following paramedian incision of the neural tube at the level of the segmental plate using colchicine, BrdU, and TUNEL methods. If the notochord and/or floor plate produces a substance(s) that promotes cell division in the basal plate neuroepithelium or that supports the survival of the motoneuron's neuroblasts, mitotic figures should not be present in the neuroepithelium nor should substantial cell death be observed in the ventral aspect of the notochord- and floor plate-deprived neural tube. Surprisingly, however, neither result was observed in the present experiments, with the exception of a considerable amount of homogeneously distributed cell death. Neuroepithelial cells continued to proliferate and gave rise to neuroblasts. Nevertheless, motoneurons failed to develop, and the neural tube was enveloped by only the basement membrane of the alar plate (S. Hirano and H. Tanaka, 1994, Dev. Growth Differ: 36, 481-488). These morphological results revealed that the cause of the development of the anterior horn lacking a neural tube in the notochord- and neural tube-eliminated embryos is not the elimination of the source of the surviving factor(s) of the motoneuron's neuroblasts, but rather the elimination of the signals to induce the motoneurons, derived from the notochord and/or floor plate. The larger amount of cell death in the neural tube on the experimental side suggests that a nonspecific survival factor(s), necessary for the survival of a variety of types of neuroblasts, is also produced by the notochord and/or floor plate.

Animals↗
PubMed1996

Interaction of rat alveolar macrophages with pulmonary epithelial cells following exposure to lipopolysaccharide.

Because both alveolar macrophages and pulmonary epithelial cells are primary target cells of inhaled endotoxin, it is of interest to study the interaction of alveolar macrophages with epithelial cells following exposure to lipopolysaccharide (LPS). Repeated bronchoalveolar lavage suggested that rat alveolar macrophages became adhesive to epithelial cells in response to intratracheally instilled LPS at 0.5 h post-exposure in vivo. Adherence of alveolar macrophages to SV40T2 (rat type II pulmonary epithelial cells transformed by SV40) was also increased following 0.5-h stimulation with LPS in vitro. The adherence was increased with dose and reached a plateau at 2 micrograms/ml LPS. The transepithelial resistance of the SV40T2 monolayer was decreased by coculture with macrophages in the presence of LPS for 4 h. The transepithelial resistance was not changed by exposure of SV40T2 alone to LPS or conditioned medium obtained from LPS-stimulated macrophages, suggesting that the intercellular interaction between alveolar macrophages and epithelial cells or unstable products of LPS-exposed alveolar macrophages was associated with the decrease in transepithelial resistance. Following the decrease in transepithelial resistance, lysis of SV40T2 was observed in the LPS-exposed coculture system. However, the lysis of SV40T2 did not occur until 12 h after the addition of LPS, indicating that the junctional change of the monolayer preceded cell death in SV40T2. Cytotoxicity of LPS-stimulated macrophages was significantly reduced by NG-monomethyl-L-arginine (NMMA), an inhibitor of nitric oxide synthase, but NMMA did not reduce the decrease in transepithelial resistance. These results suggest that the greater adherence of alveolar macrophages to epithelial cells, the junctional change of the epithelial monolayer and the lysis of epithelial cells occur in this order in the LPS-exposed alveolar macrophage-SV40T2 coculture system, and the greater adherence of alveolar macrophages may play a role in LPS-induced inflammation in the rat lung.

Animals↗
PubMed1996

Apoptotic cell death following exposure to fluoride in rat alveolar macrophages.

Since inhaled fluoride is implicated in the acute respiratory failure, cytotoxic effects of fluoride on alveolar macrophages, primary target cells of inhaled toxicants, were investigated. The LC50 of sodium fluoride was estimated to be 0.41 mM, while 1 mM sodium chloride, bromide and iodide had virtually no effects on the viability of alveolar macrophages. Photomicroscopic observation revealed that nuclei of the fluoride-exposed alveolar macrophages were fragmented. The ladder formation was observed when DNA isolated from fluoride-exposed alveolar macrophages was electrophoresed in agarose gel. These results suggest that cytotoxicity of fluoride is associated with apoptosis in rat alveolar macrophages.

Animals↗
PubMed1996

Some novel N-fatty acyl derivatives of a microbial galactosaminan.

Novel seven N-fatty acyl derivatives (degree of substitution 0.78-0.96) of a microbial galactosaminan were prepared in 59-79% yields by its reaction with fatty acid anhydrides in aqueous acetic acid-methanol. N-Acetyl and N-propionyl derivatives were soluble in water, aqueous 2% sodium hydroxide, and aqueous 2% acetic acid, but N-higher fatty acyl (> C6) derivatives were insoluble. Gel was not formed in these reactions.

Acylation↗
PubMed1996

Association of eosinophil granule major basic protein with atopic cataract.

PURPOSE: To investigate the mechanism of atopic cataract development, we examined a tissue-destroying major basic protein, derived from eosinophils, in the anterior capsule of cataractous lenses and the aqueous fluid of atopic dermatitis patients. METHODS: Major basic protein deposition in anterior capsule tissues was evaluated immunohistochemically using anti-major basic protein monoclonal antibody in three consecutive eyes from three atopic cataract patients and three consecutive eyes from three senile cataract patients. Also, major basic protein concentration in aqueous fluid obtained during cataract surgery was measured by radioimmunoassay in 12 consecutive eyes from 11 atopic cataract patients and 15 consecutive eyes from 15 senile cataract patients. RESULTS: Immunohistochemical investigation demonstrated lens epithelial major basic protein deposition in all three atopic cataracts but not in any of the senile cataracts. Major basic protein was detected in the aqueous fluid by radioimmunoassay in four of the 12 atopic cataract eyes and ranged in concentration from 11 to 70 ng/ml. No major basic protein was detected in the aqueous fluid of the 15 senile cataract eyes. CONCLUSION: Major basic protein in anterior capsule tissues and in the aqueous fluid of eyes with atopic cataract may be associated with the pathogenesis of atopic cataract.

Adolescent↗