Biomedical subjects

Kazuhiro Nakamura

Publications and source records attributed to Kazuhiro Nakamura.

70 records · Page 4Linked to original sources

PubMed2003

[Zygomycosis: two case reports and review of reported cases in the literature in Japan].

This article reports two cases of zygomycosis and analyzes the zygomycosis cases reported in the literature in Japan. Case 1 was a 43-year-old male with malignant lymphoma who presented complications of pneumonia and cerebral bleeding, leading to his death. Autopsy findings showed pulmonary lesions were due to zygomycosis. Cerebral lesion was presumed to be due to zygomycosis without pathological examination. Case 2 was a 52-year-old male with acute lymphocytic leukemia from whom 4 sputum cultures were taken that were positive for Cunninghamella elegans. Combination therapy of itraconazole and amphotericin B (AMPH) was begun, and AMPH was changed to liposomal amphotericin B. During the neutropenic period after receiving premedication for a peripheral blood stem cell transplantation performed for his underlying disease, high fever was recognized and Staphylococcus epidermidis was isolated from the blood culture. Despite the change in antibiotics administered, pneumonia also developed as a complication, causing his death. Two hundred four cases of zygomycosis have been reported in the literature in Japan: 55 cases were rhinocerebral zygomycosis, including 29 cases with no underlying disease. A premortem diagnosis was made in 34 cases by pathological findings of operation materials or drainage samples, and 24 cases were postmortem. Pulmonary, disseminated, cardiovascular, gastrointestinal and thyroidal zygomycoses were found in 144 cases, including 66 cases with leukemia. A premortem diagnosis was made in 39 cases and 120 cases were postmortem. Prognosis of rhinocerebral type was better in operated or drainage cases, and for resected cases in all other types. Five cases with allergic zygomycosis were all alive. There were only 14 cases in which isolated fungi were identified (Cunninghamella spp. from 5 cases, Mucor spp. from 2, Rhizomucor spp. from 2, and Rhizopus spp. from 5).

Adult↗

PubMed2002

Phase-locking of spontaneous and elicited ponto-geniculo-occipital waves is associated with acceleration of hippocampal theta waves during rapid eye movement sleep in cats.

We investigated the temporal relationship between hippocampal theta waves and ponto-geniculo-occipital waves (PGO) during rapid eye movement sleep (REM sleep) in cats. In addition, we analyzed the relationship between hippocampal theta waves and PGO as elicited by tone stimulus (PGO(E)) in order to quantitively characterize the PGO wave generator mechanism. The results showed that a spontaneous PGO tended to be phase-locked to the theta wave, which was more clearly observed in the single PGO than in the cluster. However, cluster PGO(E) tended to be phase-locked as well as single PGO(E). It was therefore suggested that the generator of PGO is activated in relation to the hippocampal theta wave. An acceleration of the theta wave associated with PGO occurrence was found, and was more markedly observed than with the cluster PGO. Although the magnitude of it was less than in the spontaneous case, an acceleration around the PGO(E) was also observed. These results suggest that the generators of theta and PGO receive some common activations, especially when a cluster PGO is generated. The interaction between PGO and hippocampal theta waves is expected to be involved in the possible functions of REM sleep.

Acoustic Stimulation↗

PubMed2002

Selective eosinophil adhesion to fibroblast via IFN-gamma-induced galectin-9.

Among galectin family members, galectin-9 was first described as a potent eosinophil chemoattractant derived from Ag-stimulated T cells. In the present study a role of galectin-9 in the interaction between eosinophils and fibroblasts was investigated using a human lung fibroblast cell line, HFL-1. RT-PCR, real-time PCR, and Western blot analyses revealed that both galectin-9 mRNA and protein in HFL-1 cells were up-regulated by IFN-gamma stimulation. On the one hand, IL-4, known as a Th2 cytokine, did not affect the galectin-9 expression in HFL-1 cells. We further confirmed that IFN-gamma up-regulated the expression of galectin-9 in primary human dermal fibroblasts. Flow cytometric analysis revealed that IFN-gamma up-regulated surface galectin-9 expression on HFL-1 cells. Stimulation of HFL-1 cells with IFN-gamma up-regulated adhesion of eosinophils, but not neutrophils, to HFL-1 cells. This adherence of eosinophils to HFL-1 cells was inhibited by both lactose and anti-galectin-9 Ab. These findings demonstrate that IFN-gamma-induced galectin-9 expression in fibroblasts mediates eosinophil adhesion to the cells, suggesting a crucial role of galectin-9 in IFN-gamma-stimulated fibroblasts as a physiological modulator at the inflammatory sites.

Adult↗

PubMed2002

Developmental changes in expression of small GTPase RhoG mRNA in the rat brain.

We have recently reported that RhoG, a member of Rho family small GTPases, is involved in neurite outgrowth in cultured neuronal cells. Here, we report the expression of RhoG mRNA in the developing rat brain by in situ hybridization analysis. At embryonic day 16, RhoG expression was observed throughout the ventricular zone, but was down-regulated in the region at birth. On the other hand, RhoG expression at postnatal day 20 was highly enriched in white matter tracts, including the corpus callosum, the anterior commissure, and the cerebellar white matter, and double-labeling experiments demonstrated that major RhoG-expressing cells in white matter tracts were oligodendrocytes. These results suggest distinct pre- and postnatal roles of RhoG in the development of the central nervous system.

Animals↗

PubMed2002

Transcriptional regulation of Fcgr2b gene by polymorphic promoter region and its contribution to humoral immune responses.

FcgammaRIIB1 molecules serve as negative feedback regulator for B cell Ag receptor-elicited activation of B cells; thus, any impaired FcgammaRIIB1 function may possibly be related to aberrant B cell activation. We earlier found deletion polymorphism in the Fcgr2b promoter region among mouse strains in which systemic autoimmune disease-prone NZB, BXSB, MRL, and autoimmune diabetes-prone nonobese diabetic, but not NZW, BALB/c, and C57BL/6 mice have two identical deletion sites, consisting of 13 and 3 nucleotides. In this study, we established congenic C57BL/6 mice for NZB-type Fcgr2b allele and found that NZB-type allele down-regulates FcgammaRIIB1 expression levels in germinal center B cells and up-regulates IgG Ab responses. We did luciferase reporter assays to determine whether NZB-type deletion polymorphism affects transcriptional regulation of Fcgr2b gene. Although NZW- and BALB/c-derived segments from position -302 to +585 of Fcgr2b upstream region produced significant levels of luciferase activities, only a limited activity was detected in the NZB-derived sequence. EMSA and Southwestern analysis revealed that defect in transcription activity in the NZB-derived segment is likely due to absence of transactivation by AP-4, which binds to the polymorphic 13 nucleotide deletion site. Our data imply that because of the deficient AP-4 binding, the NZB-type Fcgr2b allele polymorphism results in up-regulation of IgG Ab responses through down-regulation of FcgammaRIIB1 expression levels in germinal center B cells, and that such polymorphism may possibly form the basis of autoimmune susceptibility in combination with other background contributing genes.

Alleles↗

PubMed2002

C1q regulatory region polymorphism down-regulating murine c1q protein levels with linkage to lupus nephritis.

Much of the pathology of systemic lupus erythematosus (SLE) is caused by deposition of immune complexes (ICs) into various tissues, including renal glomeruli. Because clearance of ICs depends largely on early complement component C1q, homozygous C1q deficiency is a strong genetic risk factor in SLE, although it is rare in SLE patients overall. In this work we addressed the issue of whether genetic polymorphisms affecting C1q levels may predispose to SLE, using the (NZB x NZW)F(1) model. C1q genes are composed of three genes, C1qa, C1qc, and C1qb, arranged in this order, and each gene consists of two exons separated by one intron. Sequence analysis of the C1q gene in New Zealand Black (NZB), New Zealand White (NZW), and BALB/c mice showed no polymorphisms in exons and introns of three genes. However, Southern blot analysis revealed unique insertion polymorphism of a total of approximately 3.5 kb in the C1qa upstream region of NZB mice. C1q levels in sera and culture supernatants of LPS-stimulated peritoneal macrophages and C1q messages in spleen cells were all lower in disease-free young NZB and (NZB x NZW)F(1) mice than in age-matched non-autoimmune NZW and BALB/c mice. Quantitative trait loci analysis using (NZB x NZW)F(1) x NZW backcrosses showed that NZB microsatellites in the vicinity of the C1q allele on chromosome 4 were significantly linked to low serum C1q levels and the development of nephritis. These data imply that not only C1q deficiency but also regulatory region polymorphisms down-regulating C1q levels may confer the risk for lupus nephritis by reducing IC clearance and thus promoting IC deposition in glomeruli.

Animals↗

PubMed2002

The rostral raphe pallidus nucleus mediates pyrogenic transmission from the preoptic area.

Fever is the widely known hallmark of disease and is induced by the action of the nervous system. It is generally accepted that prostaglandin (PG) E(2) is produced in response to immune signals and then acts on the preoptic area (POA), which triggers the stimulation of the sympathetic system, resulting in the production of fever. Actually, the EP3 subtype of PGE receptor, which is essential for the induction of fever, is known to be localized in POA neurons. However, the neural pathway mediating the pyrogenic transmission from the POA to the sympathetic system remains unknown. To identify the neuronal groups involved in the fever-inducing pathway, we first investigated Fos expression in medullary regions of rats after central administrations of PGE(2). PGE(2) application to the lateral ventricle or directly to the POA strikingly increased the number of Fos-positive neurons in the rostral part of the raphe pallidus nucleus (rRPa). Most of these neurons did not exhibit serotonin immunoreactivity. Microinjection of muscimol, a GABA(A) receptor agonist, into the rRPa blocked fever and thermogenesis in brown adipose tissue induced by intra-POA as well as by intracerebroventricular PGE(2) applications. Furthermore, neural tract tracing studies revealed a direct projection from EP3 receptor-expressing POA neurons to the rRPa. Our results demonstrate that the rRPa, which has never been associated with the fever mechanism, mediates the pyrogenic neurotransmission from the POA to the peripheral sympathetic effectors contributing to fever development.

Adipose Tissue, Brown↗

PubMed2002

Significance of the detection of antineutrophil antibodies in children with chronic neutropenia.

We evaluated the clinical characteristics of 41 children with chronic neutropenia based on the quantitative analysis of antineutrophil antibodies in serum by flow cytometry. According to the strength of antineutrophil antibodies, the patients were divided into 3 groups: 12 patients presented negative antibodies, 13 patients showed weak positive antibodies, and 16 patients showed strong positive antibodies. No significant differences were seen in age of diagnosis, severity of neutropenia, and infectious complications associated with neutropenia among the 3 groups. The spontaneous resolution of neutropenia was observed in all patients with negative antibodies and in 22 of 29 patients with positive antibodies. The age of the recovery of neutropenia and the duration until spontaneous resolution of neutropenia were significantly dependent on the antibody strength at the time of diagnosis. These results demonstrate that the quantification of antineutrophil antibodies at the time of diagnosis may be useful in considering the clinical course of chronic neutropenia in childhood.

Agglutination Tests↗

PubMed2002

Globus sensation caused by gastroesophageal reflux disease.

OBJECTIVES: This study was designed to examine whether or not gastro esophageal reflux disease (GERD) is implicated in globus sensation. METHODS: The subjects were 25 patients (16 men/9 women; mean age: 51, range 25-69 years) complaining of globus sensation with one or more of four laryngeal findings suspected of having GERD, such as pooling of saliva, erythema of posterior one-third of larynx, inter-arytenoids edema, and granuloma. All 25 patients were administrated a proton pump inhibitor (PPI) for a period of 8 weeks. All were given esophageal endoscopies, laryngoscopes, and questionnaire before and after PPI dosing. The questionnaire survey was conducted to investigate changes in globus sensation and three symptoms specific to GERD including heartburn, regurgitation, and belching. Subjective symptoms were totalled by the over all scores of the three subjective symptoms which served as an index of severity of GERD. RESULTS: Fifty-two percent (13/25) of patients had reflux esophagitis. The esophagitis were improved after PPI administration except one case. The incidences of GERD symptoms were high (heart burn 68% (17/25), belching 49% (10/25) and regurgitation 76% (19/25)), and most of these symptoms ameliorated by PPI administration. The laryngeal findings were improved in all patients. Subjective symptoms were improved in 68% (17/25) of globus patients. The improvement rate of total score (before PPI dosing/after PPI dosing) was compared between the two groups: one with improved globus sensation (17 patients) and the other without (8 patients). The improvement rate was significantly higher in the group with improved globus sensation (P<0.05). This means that globus sensation improved because of the improvement in GERD. CONCLUSION: GERD is therefore concluded to be an inducing factor of globus sensation.

Adult↗

PubMed2002

MMP9 induction by vascular endothelial growth factor receptor-1 is involved in lung-specific metastasis.

The molecular mechanism of tissue-specific metastasis in tumors endogenously expressing members of the vascular endothelial growth factor (VEGF) family is not yet clear. Here we demonstrate that MMP9 is specifically induced in premetastatic lung endothelial cells and macrophages by distant primary tumors via VEGFR-1/Flt-1 tyrosine kinase (TK) and that it significantly promotes lung metastasis. In a genetic approach using mice, suppression of MMP9 induction by deletion of either VEGFR-1TK or MMP9 markedly reduced lung metastasis. Furthermore, the MMP9 levels in endothelial cells of normal lung lobes from patients carrying distant tumors were significantly elevated as compared with those from patients without tumors. Thus, a block of MMP9 induction via VEGFR-1 inhibition could be useful for the prevention of tumor metastasis in lung.

Animals↗

PubMed2002

Molecular characterization of a novel nuclear transglutaminase that is expressed during starfish embryogenesis.

We report the constitution and molecular characterization of a novel transglutaminase (EC 2.3.2.13) that starts to accumulate specifically in the nucleus in the starfish (Asterina pectinifera) embryo after progression through the early blastula stage. The cDNA for the nuclear transglutaminase was cloned and the cDNA-deduced sequence defines a single open reading frame encoding a protein with 737 amino acids and a predicted molecular mass of 83 kDa. A comparison of this transglutaminase with other members of the gene family revealed an overall sequence identity of 33-41%. A special sequence feature of this transglutaminase, which is not found in other transglutaminases, is the presence of nuclear localization signal-like sequences in the N-terminal region. Microinjection of hybrid constructs that encode the N-terminal segment fused to reporter proteins into the germinal vesicle of an oocyte produced chimeric proteins by transcription-coupled translation. It was found that the N-terminal segment alone was sufficient to effect nuclear accumulation of an otherwise cytoplasmic protein. These results suggest that the nuclear accumulation of the transglutaminase may play an important role in nuclear remodeling during early starfish embryogenesis.

Amino Acid Sequence↗

PubMed2002

Elicited ponto-geniculo-occipital waves by auditory stimuli are synchronized with hippocampal theta-waves.

The study demonstrated that ponto-geniculo-occipital (PGO) waves are phase-locked with hippocampal theta-waves during rapid eye movement (REM) sleep. A possible mechanism for influencing a PGO wave generator by hippocampal theta-waves was hypothesized. The generator is known to receive afferent inputs such as auditory input. To test this hypothesis, the temporal relationship between hippocampal theta-waves and elicited PGO waves (PGO(E)) by auditory stimuli was analysed. The analysis showed that PGO(E) were synchronized with theta-waves, but did not reset the phase of a theta-wave. Because the occurrence of PGO(E) and spontaneous PGO waves shared the same phase-dependency on theta-waves, the results strongly suggest that the PGO wave generator was driven by theta-waves, as originally hypothesized.

Animals↗

PubMed2002

Intratumoral hemorrhage due to hemangioblastoma arising from a cervical nerve root--a case report.

We describe a case of a 70 year old man suffering from sudden weakness of the left foot. Preoperative neuroimaging examinations showed an oval mass 2 cm in maximal diameter with intratumoral hemorrhage at the seventh cervical vertebra. The mass was supplied by the right lateral thoracocervical artery and was drained to the anterior spinal vein. The intraoperative findings showed the hard reddish tumor was not attached to the pia and the posterior root of the fifth cervical nerve was totally encased by the tumor. A histopathological examination revealed that hemangioblastoma encasing the posterior nerve root totally, so that the tumor was thought to arise from it. Unusual presentation of the neuroimaging examinations is described.

Aged↗

PubMed2002

Regulation of galectin-9 expression and release in Jurkat T cell line cells.

Ecalectin/galectin-9 was recently described as a novel eosinophil chemoattractant highly expressed in immune tissues. We investigated the regulation of galectin-9 expression and release in Jurkat (a T cell line) cells. We demonstrated that medium and long-sized galectin-9 isoforms were constitutively expressed, and phorbol 12-myriastate 13-acetate (PMA) upregulated the level of galectin-9 mRNA in Jurkat cells. Western blotting and flow cytometry analyses revealed that PMA stimulation resulted in the upregulation of both intracellular and surface galectin-9 protein. The stimulated Jurkat cells simultaneously released evident eosinophil chemoattractant activity (ECA). Main ECA was adsorbed by both lactose and anti-galectin-9 antibody affinity column, suggesting that the ECA was ascribed to galectin-9. When Jurkat cells were stimulated with PMA in the presence of a BB94, a matrix metalloproteinase (MMP) inhibitor, but not tissue inhibitor of metalloproteinase-1 (TIMP-1), the release of galectin-9 was suppressed in a dose-dependent manner. We further found that calphostin c, a protein kinase c (PKC) inhibitor, weakly but significantly suppressed the release of galectin-9. The present data suggested that galectin-9 production in Jurkat cells is provoked by the stimulation with PMA and that some MMP and PKC is, at least, partly involved in the release of galectin-9 from Jurkat cells.

Animals↗

PubMed2002

Association of galectin-9 with eosinophil apoptosis.

BACKGROUND: There is no information whether galectin-9 (a novel eosinophil chemoattractant) was associated with pathogenesis of eosinophilic disorders. METHODS: We assessed the expression of galectin-9 with imunostaining and in situ hybridization both in the lesion of angiolymphoid hyperplasia with eosinophilia, and peripheral blood eosinophils of eosinophilic patients (E-Eos) in comparison with those of normal volunteers (N-Eos). Regulation of expression of galectin-9 on eosinophils and the effect of galectin-9 on apoptosis of eosinophil were also evaluated. RESULTS: Many eosinophils infiltrating the site were positive for galectin-9. Surface and intracellular immunoreactive galectin-9 was more evident in E-Eos than N-Eos. When eosinophils were cultured with IL-5 in vitro, the surface galectin-9 expression of E-Eos was significantly downregulated, although that of N-Eos was not affected. Treatment of eosinophils with dexamethasone or anti-Fas antibody significantly upregulated the surface galectin-9 expression of E-Eos. In contrast, dexamethasone partially downregulated the surface galectin-9 of N-Eos, although anti-Fas antibody failed to affect on the surface galectin-9 expression. We also found that recombinant galectin-9 significantly suppressed apoptosis of E-Eos (p = 0.0431), whereas it apparently enhanced apoptosis of N-Eos (p = 0.0173). Furthermore, dexamethasone-induced apoptosis of N-Eos was significantly suppressed by galectin-9 (p = 0.0431), whereas galectin-9 failed to induce significant change in dexamethasone-induced apoptosis of E-Eos. In contrast, apoptosis induced by anti-Fas antibody in both N-Eos (p = 0.0431) and E-Eos (p = 0.0431) was enhanced by galectin-9. CONCLUSIONS: These findings suggested that galectin-9 was produced by eosinophils, and galectin-9 showed heterogeneous effects and kinetics to eosinophils, and this factor might be one of crucial factors in eosinophilic inflammation.

Angiolymphoid Hyperplasia with Eosinophilia↗

PubMed2002

Defects of granulopoiesis in patients with severe congenital neutropenia.

To confirm the abnormalities of primitive myeloid progenitor cells in patients with severe congenital neutropenia (SCN), we studied their responsiveness to hematopoietic factors including granulocyte colony-stimulating factor (G-CSF). In all SCN patients studied no abnormalities of granulocyte colony-stimulating factor receptor (G-CSFR) gene were detected by polymerase chain reaction-single-strand conformation polymorphism analysis and sequence analysis. A flow cytometric analysis of bone marrow cells based on the expression of CD34, Kit receptor, and G-CSFR demonstrated a reduced frequency of CD34+/Kit+/G-CSFR+ cells in patients with SCN. The granulocyte/macrophage (GM)-colony formation of CD34+/Kit+/G-CSFR+ cells in patients was markedly decreased at all concentrations of G-CSF in serum-deprived semisolid culture. The responsiveness of CD34+/Kit+/G-CSFR+ cells in patients showed a reduced response to the combination of stem cell factor, the ligand for flk2/flt3, and interleukin-3 with or without G-CSF in serum-deprived semisolid and liquid suspension cultures. In contrast, no difference in the responsiveness of CD34+/Kit+/G-CSFR- cells was noted between SCN patients and normal subjects. The bone marrow cells from a patient who underwent bone marrow transplantation showed a restoration of both the reduced frequency and the decreased level of GM-colony formation of CD34+/Kit+/G-CSFR+ cells. These results demonstrate that the presence of qualitative and quantitative abnormalities of primitive myeloid progenitor cells expressing G-CSFR may play an important role in the impairment of granulopoiesis in patients with SCN.

Antigens, CD34↗