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Biomedical subjects

T Hamada

Publications and source records attributed to T Hamada.

At least 505 records · Page 28Linked to original sources
PubMed1991

Immunohistochemical localization of type I, III, IV, V, and VI collagens and laminin in neurofibroma and neurofibrosarcoma.

By using antibodies to type I, III, IV, V, and VI collagens and laminin, we examined the localization of interstitial collagens and basement membrane components with indirect immunofluorescence and immunoelectron microscopy (IEM). Furthermore, the morphological changes of these collagens in malignant transformation were investigated. In neurofibroma, IEM showed type I, III, and V collagens to be present diffusely on cross-striated collagen fibrils, whereas type VI collagen was present between the fibrils. Type IV collagen and laminin were observed to surround tumor cells. In neurofibrosarcoma, tumor collagen bundles that reacted with antibodies to type I, III, V, and VI collagens were irregularly arranged. Immunofluorescent deposits that reacted with anti-type IV collagen and anti-laminin antibodies were decreased in number, showing a thin and sparse arrangement.

Collagen↗
PubMed1991

Endothelin-secreting tumor.

Recently, we have reported two cases with endothelin (ET)-secreting tumor presenting with hypertension and elevated plasma endothelin-1 (ET-1) levels. The present study examines the histopathology of the ET-secreting tumor in one of these cases. The neoplasm was located in the skin and microscopically characterized as a malignant hemangioendothelioma by remarkable intravascular proliferations of atypical endothelium with the expression of Factor VIII-related antigen in the tumor cells. The tumor enlarged rapidly with rising ET-1 and blood pressure levels. The ET-1 content and its messenger RNA expression in the tumor extract were higher than those from normal parts of skin. ET-1 may play a pathophysiological role in patients with ET-secreting malignant hemangioendothelioma.

Aged↗
PubMed1991

Effects of butylated hydroxyanisole on ornithine decarboxylase activity and its gene expression induced by phorbol ester tumor promoter.

Butylated hydroxyanisole (BHA) is a phenolic antioxidant that has been found to suppress the activity of skin tumor promoters. In this study, we investigated the effect of BHA on the activity of ornithine decarboxylase (ODC, an indicator of tumor promotion) and its gene expression induced by 12-O-tetradecanoyl-phorbol-13-acetate (TPA) in mouse skin. TPA-induced ODC activity was markedly inhibited by the topical application of 55 mumol of BHA (the inhibition rate at 6 h was about 80%). In Northern and dot-blot analysis, the TPA-induced increase in ODC mRNA was shown to be markedly reduced by the same dose of BHA (the inhibition rate at 4 h was about 60%). These results suggest the involvement of a decrease in ODC gene expression in the mechanism of the inhibition of ODC activity by BHA.

Animals↗
PubMed1991

Differential effects of cyclosporine A on ornithine decarboxylase activity induced by ultraviolet-B and PUVA in mouse skin.

The inhibitory effect of cyclosporine A (CsA) on the activity of ornithine decarboxylase (ODC) induced by phorbol ester tumor promoter has been reported. In the present study, the effects of CsA on ODC activity induced by ultraviolet-B (UV-B) and PUVA in the skin of the SKH/hr 1 hairless mouse were investigated. Topical application of CsA (1.7 mumol) to the dorsal skin irradiated with 50 mJ/cm2 UV-B did not remarkably change ODC activity. On the other hand, if CsA was applied simultaneously with 3 J/cm2 UV-A 1 h after treatment with 0.3% 8-methoxypsoralen, PUVA-induced ODC activity was suppressed by about 60% at 12 and 24 h after UV-A irradiation. In the dot blotting analysis of ODC-specific mRNA level, a significant but slight decrease in ODC mRNA level (about 20% inhibition) was observed in the PUVA-treated group compared with the control group (vehicle and UV-A). The inhibition of PUVA-induced ODC activity by CsA may have been caused in part by the decrease in ODC mRNA level and in part by a post-transcriptional regulation mechanism.

Animals↗
PubMed1991

Alteration of cartilagenous proteoglycan in psoriasis.

Articular tissue was obtained at surgery for a femoral neck fracture in a patient with psoriasis without arthritis. The proteoglycan of the cartilage of the sample was analysed biochemically. Normal cartilage is known to produce two types of proteoglycan monomers (fast- and slow-sedimenting groups), which are distinguishable by density-gradient ultracentrifugation. In the psoriatic cartilage analysed in the present study, it was shown that the former group was absent and only the latter group remained.

Cartilage, Articular↗
PubMed1991

Detection of herpes simplex viral DNA in Kaposi's varicelliform eruption using in situ hybridization method.

Herpes simplex viral DNA was detected in biopsy specimens obtained from four patients with Kaposi's varicelliform eruption using an in situ hybridization technique with biotinylated complementary DNA probes. Herpes simplex viral DNA was consistently found almost exclusively in the nuclei of giant cells and balloon cells in vesicles during day 2, 5 and 7 of the disease. In the nuclei, the viral DNA staining pattern was granular or agglomerate. No positive staining was observed in the cytoplasm.

Adolescent↗
PubMed1991

Squamous cell carcinoma developing in epidermolysis bullosa dystrophica.

Two patients with epidermolysis bullosa dystrophica recessiva who had squamous cell carcinoma are presented. Case 1 is a 40-year-old woman who had ulcers on her left lower leg. Case 2 is a 42-year-old man who had a tumor on his left first toe. Wide surgical excision with skin coverage by autograft was performed in case 1. Amputation of the toe in case 2 was performed. A review of the cases of epidermolysis bullosa dystrophica associated with cancer reported in Japan is also presented.

Adult↗
PubMed1991

Effects of ryo-kan-kyomi-sin-ge-nin-to extract on degranulation of and histamine release from rat mast cells.

The effects of Ryo-kan-kyomi-sin-ge-nin-to (RKSG)) extract, a medicinal agent traditionally used in China and Japan for treatment of asthma, on the degranulation of and histamine release from rat mast cells were studied. At a concentration of 5 mg/ml RKSG, degranulation of mast cells stimulated either by antigen (DNP-Ascaris) or compound 48/80 was markedly suppressed. At a concentration of 1-5 mg/ml RKSG, histamine release from mast cells due to application of either antigen or compound 48/80 was inhibited in a dose-dependent fashion. These results suggest that RKSG may be useful for the treatment of type I allergy-related diseases.

Animals↗
PubMed1991

Inherited corneal amyloidosis predominantly manifested in one eye.

We report 2 cases of lattice corneal dystrophy type III and gelatinous drop-like corneal dystrophy predominantly manifested in one eye. These 2 corneal dystrophies are found frequently in Japan. The case of lattice corneal dystrophy type III is the second, and the case of gelatinous drop-like corneal dystrophy is the first report at this time.

Amyloidosis↗
PubMed1991

Pathological study on beagles after long-term oral administration of cadmium.

Histopathological, histochemical, and electron microscopic examinations were performed on beagles after a long-term oral cadmium (Cd) administration of greater than 8 years. Although renal atrophy was remarkable in groups receiving doses of 50 and 100 mg/kg body weight/day, bone lesions could not be demonstrated by roentgenological and histopathologic examination. It was noticed that concomitant regeneration or recovery and cell death of the epithelium occurred in the proximal convoluted tubules. The cell death was consistent with apoptosis, a special feature of cell death, which was shown to play a major part in the tubular damage of cadmium by electron microscopic examination. Fatty degeneration of the pars recta tubules was seen to show dose-dependence. The intrarenal cadmium was localized predominantly in the cytoplasm of the proximal tubular epithelium by histochemical and ultracentrifugal cell fractionation examinations. Although no remarkable changes were found in the other organs, aggregates of siderophages in the liver and focal hemorrhage in the spleen, known as spontaneous lesions, might be related to Cd intoxication. In conclusion, the present study revealed that no bone lesions occur with Cd administration in adult beagles in spite of long-term administration. An excessive cell death to regeneration or recovery in the proximal tubules might result in the renal cortical atrophy. No remarkable changes were seen in the glomeruli and distal nephrons, which were in good agreement with Cd distribution.

Administration, Oral↗
PubMed1991

Two cases of neoplastic angioendotheliomatosis presenting with myelopathy.

We describe two patients with autopsy-proven neoplastic angioendotheliomatosis (NAE) presenting only as a transverse myelopathy for 10 to 12 months, followed by disseminated intracranial manifestations. Postmortem examination disclosed a vasculocentric distribution of neoplastic cells in various organs that stained positively with B-lymphocyte-specific monoclonal antibody. These cases were unusual because they manifested as an isolated myelopathy for many months.

Brain↗
PubMed1991

Inherited type of allelic methylation variations in a mouse chromosome region where an integrated transgene shows methylation imprinting.

It is still unclear whether or not parent-of-origin-dependent differential methylation observed in some transgenes reflects genomic imprinting of endogenous genes. We have characterized a transgene locus showing such methylation imprinting together with the corresponding native chromosome region. We show that only part of the transgene is affected by methylation imprinting and the methylation pattern is established before early prophase I during spermatogenesis. Interestingly, the native genomic region, which is mapped to the proximal chromosome 11, shows no evidence of methylation imprinting but displays heritable, strain-specific type of allelic methylation differences. The results demonstrate that transgenes do not necessarily reflect the methylation status of either the surrounding or corresponding chromosome region. In addition, inherited type of allelic methylation variations previously described in human may be widespread in mammals.

Animals↗
PubMed1991

Cisplatin suppository: preparation, release characteristics and clinical evaluation.

Cisplatin (CDDP) has attracted attention as a chemotherapeutic agent for the treatment of uterine endometrial carcinoma but causes serious side effects, including renal toxicity. CDDP suppositories containing NaCl at different concentrations were prepared to enhance the efficacy and to reduce the side effects of CDDP. The release characteristics, melting point and viscosity of the suppositories were first studied. The rate of CDDP release increased as the NaCl concentration increased: it was 12% 12 h after administration of suppositories containing no NaCl, but 32% with 0.2% NaCl. The melting point was raised by addition of NaCl: 35.5 degrees C without NaCl and 36.5 degrees C with 0.2% NaCl. Addition of 0.2% NaCl doubled the viscosity. Clinically, the suppository containing 0.06% NaCl was given to 3 patients with endometrial carcinoma twice a week for 3 weeks to examine serum CDDP levels and endometrial absorption. Patients with endometrial carcinoma showed different peak plasma platinum (Pt) levels which were as low as 0.12, 0.06 and 0.22 micrograms Pt/ml with similar patterns of change in the level. Radiographic analysis revealed many Pt particles in sections of necrosed endometria after 21d of the treatment. No side effects of CDDP were found in biochemical testing or subjective symptoms.

Aged↗
PubMed1991

Recalculation of data on 32P activity induced in sulfur in Hiroshima.

Historical data for 32P activity induced in sulfur by fast neutrons have been corrected for decay with a recent half-life value of 32P and recalculated with an experimentally determined efficiency ratio of the electroscope for beta rays from 32P and natural uranium used as a standard. Most samples would have been pure enough so that no correction for the weight of sulfur has been made. The possibility of interference with 32P activity measurements due to induced activity of other elements in the samples could also be excluded. The revised data show little difference from the original ones except for one sample which contained much impurity. Uncertainty of the data was also discussed.

Humans↗
PubMed1991

Determination of 60Co activity in steel samples in Hiroshima.

Specific activity of 60C in two steel samples taken at 687m S and 1295m NNW from the hypocenter was measured by gamma-ray spectrometry and neutron activation analysis. The results are consistent with previous data by Hashizume et al. for steel rings on the surface of roofs of buildings. content of nickel and copper in the samples was found to be too small to account for any significant 60Co production by fast neutron reactions.

Cobalt Radioisotopes↗