Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 91 records · Page 5Linked to original sources

PubMed2000

A novel gene derived from developing spinal cords, SCDGF, is a unique member of the PDGF/VEGF family.

We isolated a novel gene designated spinal cord-derived growth factor (SCDGF). Its expression was increased in chick spinal cords with embryonic development and decreased after hatching. The amino acid sequences of chick and human SCDGFs revealed a putative signal sequence followed by a CUB domain and a region homologous to the members of the platelet-derived growth factor/vascular endothelial growth factor family. Furthermore, human SCDGF secreted from the cells showed a mitogenic activity for 10T1/2 cells in vitro. These results led us to speculate that SCDGF plays an important role in the development of the spinal cord.

Amino Acid Sequence↗

PubMed2000

Switch of histamine receptor expression from H2 to H1 during differentiation of monocytes into macrophages.

It is known that histamine suppresses gene expression and synthesis of tumor necrosis factor alpha (TNF-alpha) induced by lipopolysaccharide (LPS) in human peripheral blood mononuclear monocytes (HPM) or alveolar macrophages via histamine H2 receptors. We investigated the effect of histamine and differentiation in macrophages on the expression and secretion of TNF-alpha, TNF-alpha-converting enzyme (TACE), and histamine H1 and H2 receptors by use of a leukemia cell line, U937, and HPM. Differentiation of U937 and HPM cells with 12-O-tetradecanoylphorbol-13-acetate (TPA) enhanced the H1 receptor expression and rather suppressed the H2 receptor, resulting in up-regulation of the histamine-induced expression and secretion of TNF-alpha, modulated via TACE. Therefore, histamine failed to inhibit up-regulated expression of TNF-alpha induced by LPS in macrophages. The switch from H2 to H1 receptors during differentiation in the monocyte/macrophage lineage could participate in the pathogenic processes of atherosclerosis and inflammatory reactions in the arterial wall.

ADAM Proteins↗

PubMed2000

A solitary bone cyst in the spinous process of the cervical spine: a case report.

STUDY DESIGN: A case report. OBJECTIVES: To illustrate a rare case of histologically confirmed solitary bone cyst involving the spinous process of C7. SUMMARY OF BACKGROUND DATA: A solitary bone cyst involving the spine is very unusual. Although four cases of a solitary bone cyst in the spine have been reported in the literature, the current authors have been able to find only one case of solitary bone cyst in the spinous process. All four patients reported in the literature were over 30 years of age. The patient in the current case was a 13-year-old girl with no history of trauma. METHODS: Radiographs and a computed tomography scan of the cervical spine were performed before the operation, as was a histologic examination to make a diagnosis of the lesion. RESULTS: The intraoperative findings from examination of the stagnant fluid within the lesion and the histologic examination indicated the diagnosis of a solitary bone cyst. CONCLUSIONS: A solitary bone cyst in the spine is rare, especially in the young. An osteolytic lesion in the spinous process of the spine tends to be diagnosed as an osteoblastoma or as a giant cell tumor of the bone. A solitary bone cyst of the spine, although rare, must be considered as a differential diagnosis.

Adolescent↗

PubMed2000

Detection of mononuclear cells as the source of the increased tissue factor mRNA in the liver from lipopolysaccharide-treated rats.

Tissue factor (TF) triggers the coagulation cascade reaction in vivo. Overexpression of TF mRNA is one leading cause of disseminated intravascular coagulation and thrombosis-related organ failure. In response to lipopolysaccharide (LPS) stimulation, various cell types can produce TF mRNA in vitro. However, there is currently no agreement on what types of cells in the liver overexpress TF mRNA after LPS treatment. For the first report, we found the increased TF mRNA with reverse transcription-polymerase chain reaction (RT-PCR), and confirmed a fourfold increase (p<0.001 vs. control, t-test) of the TF mRNA level with RT-competitive PCR in the liver of LPS-treated (2.0 mg/kg i.v. injection) rats. There was no significant difference in the glyceraldehyde-3-phosphate dehydrogenase mRNA level between LPS-treated rats and control rats. To clarify the localization and cellular source of LPS-induced TF mRNA, we performed in situ hybridization analysis with [35S]-labeled oligonucleotides probes, which we originally designed. We detected intense signals of TF mRNA in mononuclear cells but not in endothelial cells around the hepatic vein of LPS-treated rats. In this study, we showed that the TF mRNA level induced by LPS treatment, which may indicate mononuclear cells associated, significantly increased in the liver of rats. These results will provide circumstantial support for the therapeutic strategy that mononuclear cell should be one of the target cells to be treated in the early phase of disseminated intravascular coagulation in the liver, and that the need to suppress its overexpression of TF mRNA is essential for preventing hypercoagulable condition.

Animals↗

PubMed2000

p21 and parathyroid hormone-related peptide in the growth plate.

It is essential for terminal chondrocytes to die before the conversion of calcified cartilage to bone. We have previously demonstrated that apoptosis occurred in the terminal hypertrophic chondrocyte of the growth plate. However, the essential mechanism by which the differentiation of chondrocytes is regulated has not yet been characterized. The purpose of this study was to investigate the mechanism for regulating chondrocyte differentiation. We focused on PTHrP and p21 which regulated the differentiation of chondrocytes and investigated how these factors interacted with each other in chondrocyte differentiation in the growth plate. PTHrP was strongly positive on immunostaining at the interface between the proliferating and the upper zone of the hypertrophic chondrocytes, whereas p21 was negative. On the other hand, p21 was positive in the lower zone of hypertrophic chondrocytes. Furthermore, PTHrP up-regulated the cell proliferation and down-regulated the expression of the p21 messengers in SW-1353 chondrosarcoma cells. These findings indicated that PTHrP might be a negative regulator for p21 in the differentiation of chondrocytes.

Animals↗

PubMed2000

Genomic HLA profiles of MS in Hokkaido, Japan: important role of DPB1*0501 allele.

The polymorphism of the HLA class II genes was investigated in 97 patients with multiple sclerosis (MS) in Hokkaido, the northernmost main island of Japan. Of these, 80 patients were classified as having conventional MS and 17 as having opticospinal MS (OS-MS). Our findings confirmed a previous report that the DPB 1*0501 allele is positively associated with OS-MS (P = 0.0043). The frequency of DPB 1*0501 was also found to be higher in conventional MS patients than in controls (79% vs. 58%, P = 0.0084), although the differences were not statistically significant. Our results indicate that OS-MS is a DPB 1*0501-associated subgroup of MS, and that DPB1*0501 is also correlated with risk of conventional MS in Japanese.

Adolescent↗

PubMed2000

Dynamic viscoelastic properties and the age changes of long-term soft denture liners.

The dynamic viscoelastic properties of long-term soft denture liners were measured over a wide range of frequencies using a dynamic viscoelastometer based on a non-resonance-forced vibration principle. Changes in properties over a 3 yr period have also been monitored. One acrylic material, one fluoroelastomer, one heat cured silicone and one self-curing addition silicone were used. Complex dynamic tensile modulus (E*), tensile storage modulus (E'), tensile loss modulus (E") and loss tangent (tan delta) were determined over the frequency range from 0.01 to 100 Hz on administration of a 0.27% strain at 37 degrees C. The dynamic viscoelasticity of the acrylic and fluoroelastomer products was more sensitive to changes in frequency than that of silicone products. The acrylic material and fluoroelastomer exhibited viscoelastic behaviour whilst silicones exhibited elastic behaviour. The silicone products remained unchanged after soaking for 3 yr whilst the acrylic and fluoroelastomer products underwent significant change.

Acrylates↗

PubMed2000

Genetics of multiple sclerosis.

Multiple sclerosis (MS) is a chronic inflammatory demyelinating disease of the central nervous system. Although environmental risk factors are clearly involved in MS, the importance of genetic factors has been strongly supported by the results of studies on multiplex families, though a weak association with major histocompatibility complex (MHC) has been the only genetic feature of MS consistently observed to date. Other candidates genes have been pointed out, but none has been confirmed. Recent genome scans suggest that no single MS susceptibility locus is necessary or sufficient to cause MS, and this finding is compatible with a polygenic etiology. Furthermore, MS is a heterogeneous disorder, and thus different genes may influence its course or presentation. Actually, some candidate genes have been proposed, which contribute to the genotype-phenotype interactions in MS.

Cytokines↗

PubMed2000

Both the HLA-CPB1 and -DRB1 alleles correlate with risk for multiple sclerosis in Japanese: clinical phenotypes and gender as important factors.

The purpose of this study was to clarify the association of HLA-DRB1 and -DPB1 alleles with multiple sclerosis (MS) in Japanese, to determine whether optico-spinal MS (OS-MS) and conventional MS are immunogenetically distinct, and to verify the role of gender difference in HLA associations of MS. We studied HLA-DRB1 and -DPB1 polymorphisms in 166 Japanese patients with MS. Forty-seven patients were classified as having the optico-spinal MS (OS-MS) and 119 as having conventional MS. A lack of DPB1*0301 and a higher frequency of DPB1*0501 compared with controls (corrected P<0.0074; odds ratio=9.48) were found in OS-MS. By contrast, we found for the first time an association of DPB1*0301 with conventional MS in Japanese (corrected P=0.0444; odds ratio=3.28). Logistic analysis, adjusted for sex and age, revealed independent associations of DPB1*0301 (P=0.0004, adjusted odds ratio (aOR)=4.70), DPB1*0501 (P=0.0081, aOR= 2.50) and DRB1*1501 (P=0.0252, aOR=2.21) with conventional MS. However, the frequencies of DRB1*1501 and DPB1*0501 in male patients with conventional MS were equal to those in male controls while the DPB1*0301 frequency was increased in both male and female patients. We did not find any association of these HLA alleles with disease course and severity. In conclusion, OS-MS is a DPB1*0501-associated distinct subtype of MS, and DPB1*0301 is the most strongly associated allele with conventional MS in Japanese. In addition, gender plays an important role in HLA association with MS.

Alleles↗

PubMed2000

Sub-therapeutic exposure to polyene antimycotics elicits a post-antifungal effect (PAFE) and depresses the cell surface hydrophobicity of oral Candida albicans isolates.

Post-antifungal effect (PAFE) is defined as the suppression of growth that persists following limited exposure of fungi to antimycotics and subsequent removal of the drug. The fungal pathogen Candida albicans is the major aetiologic agent of oral candidosis, and the cell surface hydrophobicity (CSH) of this yeast is considered a critical factor contributing to its colonisation potential. As the concentration of topically prescribed antifungals reach sub-therapeutic levels at dosage intervals, the study of the polyene-induced PAFE and its impact on the CSH of oral C. albicans should be of clinical relevance. Hence the aims of this investigation were to measure the PAFE and CSH of 12 isolates of C. albicans following limited exposure (1 h) to nystatin and amphotericin B and also to investigate the ultrastructural features of yeast cells following such antifungal exposure. The yeasts were exposed to sub-lethal concentrations of nystatin (x2 MIC) and amphotericin B (x2 MIC) for a period of 1 h. Following subsequent removal of the drug, the PAFE and the CSH of the isolates were assessed by a turbidometric measurement of growth and a biphasic aqueous-hydrocarbon assay, respectively. The mean duration of PAFE of nystatin and amphotericin B were 5.99 (+/-0.49) h and 8.73 (+/-0.93) h, respectively, while the reduction in CSH following exposure to these drugs were 17.32% (P<0.05 for 83% of the isolates) and 14.26% (P<0.05 for 66% of the isolates), respectively. On scanning electron microscopy the exposed cells were seen to undergo collapse of the internal cell membrane, leaving an intact cell wall, while a proportion of cells were deflated. Some cells showed intense puckering of the cell wall, resulting in a mulberry appearance. Taken together, these data elucidate additional mechanisms by which polyene antimycotics may operate in vivo to suppress candidal pathogenicity.

Amphotericin B↗

PubMed2000

Suppression of adjuvant arthritis of rats by a novel matrix metalloproteinase-inhibitor.

BAY 12-9566 (4-[4-(chlorophenyl)phenyl]-4-oxo-2S-(phenylthiomethyl) butanoic acid) is a newly developed, synthetic matrix metalloproteinase (MMP) inhibitor (MMPI) that selectively inhibits MMP-2, MMP-3 and MMP-9 isozymes. We study the effect of BAY 12-9566 on inflammation and cartilage destruction in adjuvant-induced arthritis (AA) in rats. Rats were injected with adjuvant and treated for 21 days with vehicle, Indomethacin or BAY 12-9566. AA was assessed: by measuring arthritic index, paw volume, urinary pyridinoline (Pyr) and deoxypyridinoline (Dpyr); by examining joint inflammation; and by microscopic morphometry of articular cartilages. Oral treatment of rats for 22 days with 50 mg kg(-1) body weight/d BAY 12-9566 showed decreased AA as determined by improvement in body weight gain (P<0.01), arthritic index (P<0.05) and swelling of paws contralateral to the adjuvant injection site (P<0.05). Neutrophil infiltration and collagen degradation were also significantly lower (P<0.01) in this treatment group. Cartilage destruction was successfully suppressed (P<0.01) in rats treated with either 50 mg kg(-1) body weight/d BAY 12-9566 or 1 mg kg(-1) body weight/d Indomethacin. These results indicate that BAY 12-9566 successfully suppressed inflammation and cartilage destruction in rats with AA. Moreover, these results also suggested that MMP-2, MMP-3 and MMP-9 are involved in arthritic diseases such as rheumatoid arthritis.

Amino Acids↗

PubMed2000

Combined cutaneous hamartoma encompassing benign melanocytic naevus, vellus hair cyst and epidermoid cyst.

We describe a combined cutaneous hamartoma in a 57-year-old man, which comprised a vellus hair cyst, an epidermoid cyst and an intradermal melanocytic naevus in a single facial tumour. The vellus hair cyst was filled with keratinous material with unusual slit-like lacunae. While numerous cases of epidermoid cyst have been reported in association with an intradermal melanocytic naevus, our case is a rare example of a lesion combining several hamartomatous elements.

Cysts↗

PubMed2000

Chemotherapy-induced acral erythema: report of a case and immunohistochemical findings.

Chemotherapy-induced acral erythema (CAE) is an uncommon and distinct reaction seen in patients receiving high-dose chemotherapy. The exact pathogenic mechanisms of this disorder are still unknown. We report a 27-year-old woman who presented with red, swollen and painful macules on both palms, clinically consistent with this disease. Histological examination demonstrated vacuolar degeneration of the basal cell layer and spongiotic blisters in the epidermis, especially in the atrophied eccrine ducts and papillary oedema with mild perivascular infiltration of mononuclear and hypersegmented neutrophils. Immunohistochemistry showed that the infiltrating mononuclear cells were CD3-CD16+CD56+ leucocyte function antigen-1+, possibly natural killer cells. The eccrine ducts expressed HLA-DR and intracellular adhesion molecule-1 (ICAM-1). Our findings suggest that cell-to-cell interaction between NK cells and keratinocytes in the eccrine apparatus may induce CAE and may be involved in the pathogenesis of the skin reaction in our patient and possibly in this disease.

Adrenal Cortex Hormones↗

PubMed2000

Interactions between thermal cycled resilient denture lining materials, salivary and serum pellicles and Candida albicans in vitro. Part I. Effects on fungal growth.

In the present study, the growth of a single isolate of Candida albicans on seven saliva-, serum-coated or protein free (uncoated), thermocycled (4-70 degrees C for 1 min, respectively; 0, 1000 and 10 000 times) commercial resilient lining materials was investigated by monitoring pH changes in growth media. The inhibitory effect of the tissue conditioners on fungal growth was observed using three parameters, i.e. (i) the delay in the onset of the rapid decline in pH, (ii) the reduction in the rate of pH change and (iii) the pH minima reached. In the case of control soft liners (not thermocycled and uncoated), the antifungal effect appeared to depend upon the type of commercial soft liner used. Thus, an initial delay in pH decline and a very high pH minima were observed with fluoric and heat-cured silicone materials. High pH minima were also observed with cold-cured acrylic soft liners, whereas cold-cured silicone materials did not significantly differ from heat-cured acrylic resin (P>0.05). However, the antifungal effect of the materials was significantly reduced both by thermal cycling (ANOVA, P<0.01) and a layer of protein coating (saliva, P<0.05; serum, P<0.01). These results, taken together, suggest that the ageing of the materials and the biological fluids of the host, particularly serum, promote yeast growth on soft lining materials.

Analysis of Variance↗

PubMed2000

Interactions between thermal cycled resilient denture lining materials, salivary and serum pellicles and Candida albicans in vitro. Part II. Effects on fungal colonization.

In the present study, the growth of a single isolate of Candida albicans on saliva-, serum-coated or protein free (uncoated), thermocycled (4-70 degrees C for 1 min, respectively; 0, 1000 and 10 000 times) seven commercial soft lining materials were investigated, by adenosine triphosphate (ATP) analysis. In the case of control resilient liners (not thermocycled and uncoated), the fungal colonization appeared to depend upon the type of commercial resilient liner used. Thus, the lowest colonization was observed with fluoric and heat-cured silicone materials, cold-cured silicone materials, except for one product, and heat-cured acrylic resin exhibited the highest colonization capacity, and cold-cured acrylic resilient liners exhibited the intermediate. However, the fungal colonization on the materials was significantly promoted both by thermal cycling (ANOVA, P<0.01) and a layer of protein coating (saliva, P<0.01; serum, P<0.01). These results, taken together, suggest that the ageing of the materials and the biological fluids of the host promote yeast colonization on resilient lining materials.

Acrylic Resins↗

PubMed2000

Effect of serum concentration on Candida biofilm formation on acrylic surfaces.

The biofilm formation of the oral fungal pathogen Candida on denture acrylic strips coated with saliva, serum and, saliva-serum pellicle were examined in vitro using Candida albicans (four isolates), Candida glabrata (three isolates) and Candida tropicalis (three isolates). The degree of biofilm activity varied depending upon both the isolate and the pellicle. Significantly increased biofilm activity on the pellicle (particularly serum)-coated strips was observed with three isolates of C. albicans and another of C. glabrata on protein-coated acrylics, with increasing concentration of serum in the pellicle. Similar trends were observed with one isolate of C. albicans and C. glabrata, although the effects of pellicles were not significant. In contrast, with all three isolates of C. tropicalis and a single isolate of C. glabrata, although the biofilm activity on the protein-free control strips was significantly higher than that of saliva-coated strips, the increase in activity of pellicle-admixed biofilm depended upon the serum concentration. Candidal biofilm formation on acrylic surfaces is essentially promoted with increasing concentration of serum in the pellicle. This suggests that inflammation in the oral environment would facilitate fungal colonization on denture acrylic.

Acrylic Resins↗

PubMed2000

Ovarian yolk sac tumor with virilization during pregnancy: immunohistochemical demonstration of Leydig cells as functioning stroma.

A case is reported of yolk sac tumor occurring in the left ovary and complicated by pregnancy. The 22-year-old patient presented at 28 weeks gestation with virilization and elevated serum levels of testosterone and alpha-fetoprotein. The tumor showed the typical features of yolk sac tumor with a mixture of islands of Leydig cells. The accumulations of Leydig cells were well demarcated from the cellular components of the yolk sac tumor and were distributed throughout the tumor, although with predominant localization at the periphery. By immunohistochemistry the Leydig cells were intensely positive for vimentin and negative for cytokeratins, allowing clear distinction from the cell components of the yolk sac tumor, which were positive for cytokeratins and negative for vimentin. Testosterone was also identified in the cytoplasm of the Leydig cells. After tumor resection the testosterone and alpha-fetoprotein levels declined simultaneously; this, together with the immunohistochemical demonstration of testosterone, indicates that the Leydig cells were responsible for the endocrine manifestations. Furthermore, antibodies against inhibin alpha-subunit and calretinin could be used to detect the Leydig cells. The present case, a combination of yolk sac tumor and Leydig cells acting as a functioning stroma and causing virilization during pregnancy, is very rare.

Adult↗

PubMed2000

Synaptotagmin IV is present at the Golgi and distal parts of neurites.

Synaptotagmin IV (SytIV) is an immediate early gene induced by membrane depolarization in PC12 cells and in rat brain. However, little is known about the function of SytIV or the functional relationship between SytIV and SytI, because SytIV has yet to be localized. Here we show that SytIV was localized at the Golgi and distal part of neurites in nerve growth factor-differentiated PC12 cells and cultured hippocampal neurons by immunocytochemistry using an isoform-specific antibody (anti-SytIV). These SytIV signals were not colocalized well with SytI signals. Upon membrane depolarization, SytIV signals were increased at both the Golgi and distal part of neurites within several hours in both types of cells. We further show that the increase of SytIV protein levels results from protein kinase A-dependent gene up-regulation. In hippocampal neurons, SytIV was developmentally regulated. These results suggest that SytIV may play a role at the Golgi and tips of neurites during development and synaptic plasticity.

Animals↗