Search PubMed⌕ Search

Biomedical subjects

K Nemoto

Publications and source records attributed to K Nemoto.

At least 127 records · Page 7Linked to original sources
PubMed1996

Ganglioneuroma: computed tomography and magnetic resonance features.

12 patients who had histological proven ganglioneuromas were investigated by computed tomography (CT) and magnetic resonance (MR) imaging. CT scans (n = 11), conventional spin-echo MR images (n = 10) and dynamic MR images (n = 5) were acquired. All lesions showed a well defined, oval shape. Five lesions (42%) showed calcification which was punctate in four and coarse in one on CT. CT attenuation was predominantly low in three of 10 (30%) and intermediate in the remaining seven (70%). In all lesions MR signals were mainly of low intensity on T1 weighted images (T1WI) and of high intensity on T2 weighted images (T2WI). Dynamic MR studies in five cases showed a lack of early enhancement but gradual increasing enhancement. One case had a ganglioneuroblastoma component which showed soft-tissue density and coarse calcifications on CT scans, MR images with intermediate intensity on T1WI and T2WI and early enhancement and little washout on dynamic MR images. In conclusion, ganglioneuroma typically shows punctate calcification and low attenuation on CT and marked hyperintensity on T2WI with gradual increasing enhancement on dynamic MR images. If a ganglioneuroma has atypical CT and MR features, coexistence of a malignant component should be considered.

Adolescent↗
PubMed1996

[Analysis of locally controlled esophageal carcinomas treated with radiotherapy].

Of 227 esophageal carcinomas treated with a radiation dose of 60 Gy or more, 100 patients had no tumor or ulceration (with or without stenosis) of the esophagus after irradiation. We analyzed local control factors of these 100 patients to determine the need for further treatment. The cumulative local control rate at five years was 40% in all cases, 37% in 21 cases without any stenosis of the esophagus and 40% in 79 cases with stenosis. The presence of stenosis of the esophagus after irradiation was not a critical factor in predicting final local control. Local recurrence of tumors with findings of Borrmann III or Borrmann IV by the pretreatment esophageal barium study, tumors controlled after a total dose of more than 80 Gy, tumors without low dose rate telecobalt therapy (LDRT; 1 Gy/hour, 5 to 7Gy/day, a total dose of 12 to 15 Gy) as boost therapy, and apparently controlled tumors with a stenotic ratio of 60% or more or with 5 cm or more length of stenosis of the esophagus after irradiation was significantly higher than that of the others (p < 0.05). Multivariate analysis revealed that findings of pretreatment barium study, total dose, with or without LDRT, and length of stenosis of the esophagus after irradiation were significantly important factors in local control. Members of the high risk group of apparently controlled tumors should undertake surgical treatment or further intensive chemotherapy.

Aged↗
PubMed1995

Effects of a structural change in collagen upon binding to conditioned dentin studied by 13C NMR.

To develop a better adhesive functional monomer, it is imperative to understand the adhesion mechanisms of the resin to the dentin surface. Bond strength to the decalcified dentin surface pretreated with dentin primer, an aqueous ethanol solution of N-methacryloyl glycine, increases by increasing the water content in the primer. The aqueous primer could increase the thickness of the hybrid layer. The structural change of dentinal collagen with NM alpha A was studied by using a model compound for collagen,--(1Pro-2Pro-3Gly)10--, by 13C nuclear magnetic resonance (NMR). The model compound was aggregated in ethanol but dissociated in water. It was found that NM alpha A effectively dissociated the aggregated model compound in water. The dissociation of decalcified dentin was essential to create a thick hybrid layer that could afford a higher bond strength to dentin.

Adhesiveness↗
PubMed1995

A case of uterine cervical adenoid cystic carcinoma: immunohistochemical study for basement membrane material.

BACKGROUND: Adenoid cystic carcinoma is a rare neoplasm of the cervix. Only two reports of immunohistochemical studies for basement membrane material in adenoid cystic carcinoma of the cervix have been reported. CASE: An 80-year-old Japanese woman complained of atypical vaginal bleeding and underwent removal of a cervical polyp; the biopsy specimen revealed a solid variant of adenoid cystic carcinoma. The tumor was composed of nests and nodules of small carcinoma cells, and there were few characteristic cribriform patterns. Immunohistochemical findings for type IV collagen and laminin revealed intercellular cylinders composed of basement membrane material in the solid area without a cribriform pattern. CONCLUSION: The immunohistochemical finding of intercellular cylinders that reacted for type IV collagen was useful for the diagnosis of a solid variant of adenoid cystic carcinoma.

Aged↗
PubMed1995

Adhesion of composite to polished dentin retaining its smear layer.

OBJECTIVES: This study was designed to measure the adhesion of a composite to the smear layer. METHODS: An experimental aqueous bonding agent was supplied in the form of two liquids. One contained methacryloyl tyrosine amide (MTYA), glyceryl methacrylate (GM), dimethylaminoethylmethacrylate and benzene sulfinic acid sodium salt, and the other contained glutaraldehyde, succinic acid and 2-hydroxy-3-(3,4-dimethyl-9-oxo-9H-thioxanthen-2-yloxy)-N,N, N-trimethy-1-propanaminium chloride (QTX). QTX is a unique water-soluble photo polymerization initiator. The application times and irradiation times of the experimental aqueous bonding agent were varied. RESULTS: The highest mean bond tensile strength was obtained by irradiating the bonding agent for 1 min. A 3 min irradiation decreased the mean bond strength when the bonding agent was applied to the polished dentin surface for 1, 3 or 5 min. The mean values resulting from the application of experimental aqueous bonding agent were higher than those from a commercially available bonding agent which preserved or modified the smear layer. There was a significant decrease in the bond strength after 500 or 2000 thermocycles in specimens with a 5 min application of the bonding agent, but there was no significant decrease in the bond strength when the application time was for 1 or 3 min. SEM observation showed the formation of a hybrid layer with a thickness of approximately 1-1.5 micrometers. SIGNIFICANCE: The aqueous bonding agent tested in this investigation was capable of penetrating the smear layer and the bond strength exceeded the values obtained by bonding agents that remove the smear layer.

Analysis of Variance↗
PubMed1995

Autoimmune-prone (NZW x BXSB)F1 (W/BF1) mice escape severe thrombocytopenia after treatment with deoxyspergualin, an immunosuppressant.

Male (NZW x BXSB)F1 mice spontaneously develop a disease which closely resembles human systemic autoimmune disease, involving idiopathic thrombocytopenic purpura and glomerulonephritis. We investigated whether autoimmune thrombocytopenia in the mice responded to deoxyspergualin, as immunosuppressant. Deoxyspergualin completely prevented the development of thrombocytopenia and suppressed the increase in circulating autoantibodies against platelets. This agent also ameliorated lupus nephritis. These findings suggest that deoxyspergualin may be effective in the prevention of idiopathic thrombocytopenic purpura.

Animals↗
PubMed1995

Cross-reactivity between human sialyl Lewis(x) oligosaccharide and common causative oral bacteria of infective endocarditis.

The expression of sialy-Lewis(x) (sLe(x); Neu5Ac alpha 2-3 Gal beta 1-4) (Fuc alpha 1-3) GlcNAc-R) on oral bacteria producing infective endocarditis was determined by a whole-cell enzyme linked immunosorbent assay and an immunoelectron microscopy using the well-characterized anti-sLe(x) monoclonal antibody SNH-3 (mAb SNH-3; IgM class). mAb SNH-3 reacted strongly with whole cells of oral bacteria: Streptococcus sanguis, Streptococcus mutans, Streptococcus mitis, Streptococcus salivarius, Streptococcus intermedius, Streptococcus constellatus, Streptococcus anginosus, Streptococcus pyogenes, Actinobacillus actinomycetemcomitans, Eikenella corrodens and Porphyromonas gingivalis. The negatively stained immuno-electron micrograph of Streptococcus pyogenes showed many reactive gold particles on the cell surface. Our findings demonstrated the existence of immunologic mimicry between the sLe(x) oligosaccharide and cell surface antigens of many species associated with infective endocarditis. We propose the hypothesis that if these bacteria escape their normal habitats, the surface components that mimic the sLe(x) oligosaccharide might bind to host antigens of the selectin family which could promote binding to endothelial cells and, consequently, initiation of the events leading to infective endocarditis.

Antibodies, Monoclonal↗
PubMed1995

Immediate-early, transient induction of the interleukin-1 beta gene in mouse spleen macrophages by ionizing radiation.

In murine spleen cells, x ray irradiation induces the expression of the IL-1 beta gene at multiple phases of the peak time. We analyzed the immediate-early phase of IL-1 beta mRNA accumulation. To determine the lineage of cells that showed the immediate response to irradiation, normal spleen cells were analyzed by Northern blotting and in situ hybridization after separation by magnetic antibodies against specific cell-surface antigens. Although most of the spleen macrophages continuously expressed a low level of IL-1 beta mRNA, a portion of the macrophage population transiently accumulated large amounts of IL-1 beta message immediately after irradiation. A macrophage-like leukemia cell line that resembles these inducible macrophages was identified. A similar immediate-early and transient increase in the IL-1 beta mRNA level occurred when cultured spleen cells were irradiated with a low dose (3 Gy) of x rays. In contrast, the x ray-inducible expression of the IL-1 beta gene was immediate and continuous, not transient, in spleen cells from whole-body irradiated mice. Results of the run-on transcription assay and the determination of the decrease in the message using cultured spleen and macrophage-like leukemia cells indicated that x ray irradiation appears to activate the transcription of the IL-1 beta gene and partially stabilize the message. The results show that the x ray-induced immediate-early accumulation of IL-1 beta mRNA is regulated at both the transcriptional and post-transcriptional levels in an as yet unidentified population of spleen macrophages.

Animals↗
PubMed1995

Expression of IL-1 beta mRNA in mice after whole body X-irradiation.

IL-1 beta is a stimulator of hematopoietic and inflammatory systems, and also acts as a radioprotector. After whole-body exposure to sublethal doses of ionizing radiation, the IL-1 beta mRNA level in spleen cells increases for a short time prior to regeneration of the spleen. We analyzed spleen cells of C3H/He mice after whole-body irradiation with 3 Gy x-rays to determine the cause of this short-term increase in the transcription level. An increase in the level of the message in spleen cells, found by Northern blot hybridization, reached its peak 5 to 7 days after irradiation. There was a low correlation between the curves of the mRNA level and the ratio of monocyte/macrophage lineage cells; a typical source of the message. Spleen macrophages that produce a large amount of the message were found 7 days after irradiation in an in situ hybridization experiment in which heterogeneous spleen cell populations were used. In contrast, spleen cells had no detectable levels of macrophages rich in IL-1 beta mRNA before and 17 days after irradiation. Additionally, the population of message-rich cells was 9.4% of the total number of monocytes/macrophages in the spleen. These results suggest that the short-term increase in IL-1 beta mRNA is a result of the heterogeneous differentiation of a subpopulation of spleen macrophages before regeneration of the spleen.

Animals↗
PubMed1995

An investigation of gram-negative tannin-protein complex degrading bacteria in fecal flora of various mammals.

Gram-negative tannin-protein complex degrading bacteria (T-PCDB) were first isolated from animals except for the koala. The occurrence of T-PCDB in feces of 15 species of mammals with different feeding habits was investigated. T-PCDB occurred in 7 of 54 horses but they could not be isolated from other mammals tested. These T-PCDB comprised less than 0.1% of the facultative anaerobic microflora in horse feces and it was much less than that previously reported in koala feces ( > 60%). A total of 7 T-PCDB fecal isolates showed a range of phenotypic diversities. They were all Gram-negative rods of various sizes and shapes including coccoidal rod. Although all produced tannase, no strain showed to have gallate decarboxylase. A total of 23 representative strains belonging to the family Pasteurellaceae were also tested for tannase production. Two strains, Haemophilus actinomycetemcomitans NIAH-10202T and Haemophilus segnis NIAH-10183T which were isolated from human oral cavity were detected positive for tannase.

Animals↗
PubMed1995

In vitro study of deoxymethylspergualin on functions of lymphocytes and bone marrow cells from healthy volunteers.

15-Deoxy-11-O-methylspergualin (MeDSG) is an analogue of 15-deoxyspergualin, which has potent immunosuppressive activity. The present study was designed to evaluate the in vitro effects of MeDSG on the functions of peripheral blood mononuclear cells (PBMC) and bone marrow cells derived from healthy volunteers. MeDSG failed to suppress the proliferation of PBMC stimulated with mitogens. In the allogeneic mixed lymphocyte reaction, MeDSG strongly suppressed both the proliferation of lymphocytes and the generation of alloreactive cytotoxic T lymphocytes, but did not affect the cytolytic activity of the established cytotoxic T lymphocytes. MeDSG had no effect on the cytolytic activity of natural killer cells. Concerning positive hematopoietic regulators, MeDSG had a slight enhancing effect on the release of granulocyte-macrophage colony-stimulating factor and a slight inhibitory effect on the release of interleukin-6 and granulocyte-colony-stimulating factor from PBMC stimulated with mitogens. Significantly, MeDSG completely suppressed the colony formation of bone marrow cells in the presence of granulocyte colony-stimulating factor.

Bone Marrow↗
PubMed1995

[A case of spastic paraparesis, mental retardation and thinning of corpus callosum].

There are several reports of the patients who have peculiar clinical presentation, that is, spastic paraparesis, mental disturbance and thinning of corpus callosum. We presented a sporadic case with similar symptoms. He was born by normal vaginal delivery without problems from consanguineous parents. His development had delayed since his infantile period. He started to have spasticity of the legs at the age 13 years and it worsened with advancing age. On examination at age 19, he was mentally slow, his full-scale IQ being 35. The tone in the arms was slightly increased and marked in the legs. The finger to nose test caused mild dysmetria. Rest of the neurological examinations were normal. MRI demonstrated characteristic thinning of corpus callosum, dominant in anterior portion. In addition, it showed wide cavum vergae and cavum septi pellucidi, and abnormal high intensity in periventricular white matter. The findings of MRI were possibly suggestive of the static developmental disturbance of brain.

Adult↗
PubMed1995

Deoxyspergualin is a new radioprotector in mice.

A novel immunosuppressant, deoxyspergualin, given at doses of 2.5 to 20 mg/kg/day on days -3, -2 and -1 before X irradiation protected BALB/c mice from the lethal effects of radiation in a dose-dependent manner. The dose of radiation that killed 50% of the mice within 30 days was 5.63 Gy for mice receiving radiation alone, but was 7.13 Gy in the mice given deoxyspergualin at 20 mg/kg. Prior administration of deoxyspergualin ameliorated leukopenia and thrombocytopenia induced by sublethal irradiation, and significantly increased the number of femoral spleen colony-forming units (CFU-S) that survived irradiation. Deoxyspergualin also reduced the proportion of CFU-S in S phase, as determined by in vitro sensitivity to hydroxyurea. These findings suggest that deoxyspergualin may be effective in the prevention of hematopoietic injury caused by radiotherapy.

Animals↗
PubMed1995

Effect of repeated cold stress on mouse stomach histidine decarboxylase.

The effect of repeated cold stress (RCS) on both mRNA level and enzyme activity of stomach histidine decarboxylase (HDC) was studied in ddY mice. Following 1-day treatment of RCS, stomach HDC activity, but not its mRNA level, increased two fold. Following 3-day treatment of RCS, which is the essential period for the induction of hyperalgesia in mice, HDC mRNA level and enzyme activity increased in the stomach. After cessation of RCS treatment, HDC mRNA level decreased and reached the level of non-RCS treated mice, but HDC activity did not. The stomach from the 1-day RCS-treated mouse contained proteolytic activity, which converts the in vitro-translated 74 kD HDC species into the 53 kD HDC species. These data demonstrate that RCS-treated mouse stomach induces both the de novo synthesis of the 74 kD HDC species and its proteolytic cleavage to 53 kD HDC species.

Animals↗
PubMed1994

Mutation of low affinity nerve growth factor receptor gene in spontaneously hypertensive and stroke-prone spontaneously hypertensive rats: one of the promising candidate genes for hypertension.

There is evidence that abnormal formation of the sympathetic nervous system might be important for pathogenesis of hypertension. In the present study we analyzed nucleotide sequences of low affinity nerve growth factor receptor (LNGFR) genes in the spontaneously hypertensive rat and its stroke-prone substrain. There was a point mutation generating an amino acid substitution in signal peptide of these LNGFRs. This result suggested that the mutated LNGFR gene is one of the promising candidate genes for hypertension.

Amino Acid Sequence↗
PubMed1994

Identification of matrix metalloproteinase 9 in rabbit osteoclasts.

Osteoclasts are multinucleate giant cells that play key roles in bone resorption. To identify genes predominantly expressed in osteoclasts, we screened a cDNA library of osteoclasts with cDNA probes of osteoclasts and alveolar macrophages. Clones specifically hybridizing to the osteoclast probe were isolated and sequenced. The nucleotide sequence of one such clone, F17, was found to share significant similarity with the sequences of human and mouse matrix metalloproteinase 9 (MMP-9) cDNA. By isolation and sequencing of the full-length cDNA, F17 was revealed to encode the rabbit counterpart of MMP-9. By Northern blotting, messenger RNA for MMP-9 was found to be highly and predominantly expressed in isolated osteoclasts when compared with its level in alveolar macrophages and other tissues. By gelatin zymography, gelatinase activity was detected in conditioned medium of isolated osteoclasts, suggesting that MMP-9 is secreted by isolated osteoclasts. Expression of MMP-9 was also observed in in vivo osteoclasts in metacarpal bones of newborn rabbits by in situ hybridization. These facts suggest that MMP-9 is one of the major proteases produced by osteoclasts and possibly plays a role in osteoclastic bone resorption.

Amino Acid Sequence↗
PubMed1994

Molecular cloning of a possible cysteine proteinase predominantly expressed in osteoclasts.

Osteoclasts are multinucleate giant cells playing key roles in bone resorption. These cells solubilize mineralized bone matrix by means of acid and protease action; however, the precise mechanism of this process is not well known. Recently, we succeeded in the isolation of pure osteoclasts from rabbit bones and constructed a cDNA library. Using a differential screening procedure, two genes expressed predominantly in osteoclasts compared with spleen cells were isolated (Tezuka, K., Sato, T., Kamioka, H., Nijweide, P. J., Tanaka, K., Matsuo, T., Ohta, M., Kurihara, N., Hakeda, Y., and Kumegawa, M. (1992) Biochem. Biophys. Res. Commun. 186, 911-917). One of them, OC-2, was found to encode a possible cysteine proteinase structurally related to cathepsins L and S. By in situ hybridization, OC-2 was confirmed to be expressed in osteoclasts in vivo. By Northern blot analysis, OC-2 was highly and preferentially expressed in osteoclasts compared with other tissues such as kidney, liver, spleen, and lung. The predominant expression of OC-2 in osteoclasts may suggest that OC-2 encodes a protein, possibly a cysteine proteinase, that plays an important role in osteoclastic bone resorption.

Amino Acid Sequence↗