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Biomedical subjects

N Tabata

Publications and source records attributed to N Tabata.

At least 19 recordsLinked to original sources
PubMed2001

Role of natural killer cells in resistance against friend retrovirus-induced leukemia.

We have previously shown that immunization with a synthetic peptide that contains a single CD4(+) T-cell epitope protects mice against immunosuppressive Friend retrovirus infection. Cells producing infectious Friend virus were rapidly eliminated from the spleens of mice that had been immunized with the single-epitope peptide. However, actual effector mechanisms induced through T-helper-cell responses after Friend virus inoculation were unknown. When cytotoxic effector cells detected in the early phase of Friend retrovirus infection were separated based on their expression of cell surface markers, those lacking CD4 and CD8 but expressing natural killer cell markers were found to constitute the majority of effector cells that lysed Friend virus-induced leukemia cells. Depletion of natural killer cells by injecting anti-asialo-ganglio-N-tetraosylceramide antibody did not affect the number of CD4(+) or CD8(+) T cells in the spleen, virus antigen-specific proliferative responses of CD4(+) T cells, or cytotoxic activity against Friend virus-induced leukemia cells exerted by CD8(+) effector cells. However, the same treatment markedly reduced the killing activity of CD4(-) CD8(-) effector cells and completely abolished the effect of peptide immunization. Although the above enhancement of natural killer cell activity in the early stage of Friend virus infection was also observed in mice given no peptide, these results have demonstrated the importance and requirement of natural killer cells in vaccine-induced resistance against the retroviral infection.

Amino Acid Sequence↗
PubMed2001

Cladospolide D, a new 12-membered macrolide antibiotic produced by Cladosporium sp. FT-0012.

A new antibiotic termed cladospolide D was isolated along with the known cladospolides A and B from the fermentation broth of Cladosporium sp. FT-0012 by solvent extraction, ODS column chromatography and preparative HPLC. The structure of cladospolide D was deduced to be (E)-2-dodecen-5-hydroxy-11-olide-4-one. Cladospolide D showed antifungal activity against Pyricularia oryzae and Mucor racemosus.

Anti-Bacterial Agents↗
PubMed2000

Roles of endogenous retroviruses and platelets in the development of vascular injury in spontaneous mouse models of autoimmune diseases.

MRL/MpJ-lpr/lpr (MRL/lpr) mice spontaneously develop immune complex-mediated glomerulonephritis, granulomatous arteritis, and thrombocytopenia. Recent genetic analyses in a few different strains of lupus-prone mice have pointed out a close correlation between autoantibodies reactive with the endogenous retroviral env gene product, gp70, and the development and severity of glomerulonephritis. We have also shown that autoantibodies reactive with endogenous retroviral gp70 are closely correlated with the development of necrotizing polyarteritis in another lupus-prone strain of mice, SL/Ni. However, suggested pathogenicity of anti-gp70 autoantibodies has not yet been directly tested. To examine if anti-gp70 autoantibodies induce glomerular and vascular pathology, we established from unmanipulated MRL/lpr mice hybridoma clones that secrete monoclonal antibodies reactive with endogenous xenotropic viral env gene products. As reported separately, a high proportion of these anti-gp70 antibody-producing hybridoma clones induced in syngeneic non-autoimmune and severe combined immunodeficiency mice proliferative or wire loop-like glomerular lesions with granular deposits of gp70, IgG, and C3 in affected glomeruli. Some mice transplanted with these anti-gp70 autoantibody-producing hybridoma cells also showed massive subendothelial deposition of electron-dense materials in small arterioles in the kidneys. Furthermore, we identified an IgG2a-producing anti-gp70 hybridoma clone that induced microvascular intraluminal platelet aggregation, thrombocytopenia, and amenia upon transplantation into syngeneic non-autoimmune mice. This anti-gp70 autoantibody bound onto the surfaces of mouse platelets, and specifically precipitated a platelet protein with an approximate relative molecular mass of 40000. Attachment of activated platelets to the intimal surfaces of small arteries was also observed by electron microscopy in mice transplanted with the pathogenic anti-gp70 IgG2a-producing hybridoma cells, suggesting an interaction between antibody-bound platelets and endothelial cells.

Animals↗
PubMed2000

A frozen newborn infant: froth in the air-passage after thawing.

We performed an autopsy on a frozen newborn infant who was found in a freezer at -18 degrees C. After thawing, froth emerged from the nostrils and was present in the trachea. Sometimes froth may be seen in the air-passage in cases of strangulation and drowning. In our case, however, there was neither proof of asphyxia due to strangulation nor drowning. The existence of the froth indicates that the infant was probably in a state of respiratory distress before death. Histologic findings of the lung showed that the infant did not suffer from respiratory disorders such as respiratory distress syndrome. Karyopyknosis and vacuolation of the keratinocytes, shrinkage of the hepatocytes, dilatation of the sinusoid, spaces between heart muscle fibers and deep staining of the nuclei and hemolysis were characteristic in our case. This case shows that froth persists in the internal air-passage for a long time as a result of freezing. Moreover, the froth in the air-passage, along with the findings of the lungs, demonstrates that the newborn infant was born alive.

Autopsy↗
PubMed2000

Induction of microthrombotic thrombocytopenia in normal mice by transferring a platelet-reactive, monoclonal anti-gp70 autoantibody established from MRL/lpr mice: an autoimmune model of thrombotic thrombocytopenic purpura.

MRL/MpJ-lpr/lpr (MRL/lpr) mice spontaneously develop immune complex-mediated glomerulonephritis and thrombocytopenia. Although the presence of cross-reactive anti-phospholipid antibodies in sera of MRL/lpr mice has been demonstrated, possible relationships between detected autoantibodies and the development of thrombocytopenia have not been elucidated. Recent genetic analyses in a few different strains of lupus-prone mice have pointed out a close correlation between autoantibodies reactive with endogenous retroviral env gene product, gp70, and the development and severity of glomerulonephritis. In the process of establishing possibly nephritogenic anti-gp70 autoantibody-producing hybridoma cells from MRL/lpr mice, we identified an IgG2a-producing anti-gp70 hybridoma clone that induced microvascular intraluminal platelet aggregation, thrombocytopenia, and amenia upon transplantation into syngeneic non-autoimmune mice. This and two other anti-gp70 antibodies bound onto the surface of mouse platelets, and purified IgG2a of the anti-gp70 autoantibody induced glomerular lesions with characteristics of thrombotic thrombocytopenic purpura when injected into non-autoimmune mice. The pathogenic anti-gp70 autoantibody specifically precipitated a platelet protein with an approximate relative molecular mass of 40 000.

Animals↗
PubMed2000

Establishment of monoclonal anti-retroviral gp70 autoantibodies from MRL/lpr lupus mice and induction of glomerular gp70 deposition and pathology by transfer into non-autoimmune mice.

Several strains of mice, including MRL/MpJ mice homozygous for the Fas mutant lpr gene (MRL/lpr mice), F(1) hybrids of New Zealand Black and New Zealand White mice, and BXSB/MpJ mice carrying a Y-linked autoimmune acceleration gene, spontaneously develop immune complex-mediated glomerulonephritis. The involvement of the envelope glycoprotein gp70 of an endogenous xenotropic virus in the formation of circulating immune complexes and their deposition in the glomerular lesions have been demonstrated, as has the pathogenicity of various antinuclear, antiphospholipid, and rheumatoid factor autoantibodies. In recent genetic linkage studies as well as in a study of cytokine-induced protection against nephritis development, the strongest association of serum levels of gp70-anti-gp70 immune complexes, rather than the levels of antinuclear autoantibodies, with the development and severity of glomerulonephritis has been demonstrated, suggesting a major pathogenic role of anti-gp70 autoantibodies in the lupus-prone mice. However, the pathogenicity of anti-gp70 autoantibodies has not yet been directly tested. To examine if anti-gp70 autoantibodies induce glomerular pathology, we established from unmanipulated MRL/lpr mice hybridoma clones that secrete monoclonal antibodies reactive with endogenous xenotropic viral env gene products. Upon transplantation, a high proportion of these anti-gp70 antibody-producing hybridoma clones induced in syngeneic non-autoimmune and severe combined immunodeficiency mice proliferative or wire loop-like glomerular lesions. Furthermore, deposition of gp70 in glomeruli and pathological changes were observed after intravenous injection of representative clones of purified anti-gp70 immunoglobulin G, demonstrating pathogenicity of at least some anti-gp70 autoantibodies.

Animals↗
PubMed2000

Biophysical assessment of persistent effects of moisturizers after their daily applications: evaluation of corneotherapy.

BACKGROUND: Although effective moisturizers can improve xerotic skin changes immediately, their effects are only transient, because the materials applied to the stratum corneum (SC) are easily shed from the skin surface by the daily desquamation process. However, there are a few lines of clinical as well as experimental evidence suggesting that, once application of effective moisturizers is repeated daily, they may produce persistent effects without being influenced by the desquamation of the skin surface. If we can expect such pharmacological effects by simple repeated applications of moisturizers on the skin surface, it will provide a great motivation for the introduction of corneotherapy into the treatment of xerotic skin problems. OBJECTIVE: This study was designed not only to confirm the feasibility of corneotherapy but to propose a practical method to assess such long-lasting effects of moisturizers by using biophysical methods. METHODS: We conducted applications of various moisturizers twice daily to different areas of the flexor surface of the forearms for the initial 5 days of the first week. Thereafter, we performed biophysical measurements of the SC of these areas in the second week, namely 3, 5 and 7 days after their last applications. RESULTS: Daily repeated applications of moisturizers did not induce any change in the water barrier function of the SC or in the size of desquamating corneocytes, a parameter for turnover rate of the SC. However, they substantially increased high-frequency conductance, a parameter for the hydration state of the skin surface, for several days in both normal individuals and patients with atopic xerosis, although the lasting effects were shorter in the latter. The obtained data enabled us to rank the efficacy of moisturizers either according to the duration of the lasting effects or the magnitude of an increase in the hydration levels of the SC. CONCLUSION: The present results confirmed the feasibility of corneotherapy, in which even simple application of moisturizers targeted at the SC can produce unexpected persistent clinical effects after their repeated treatments. The method described in this study constitutes a practical assay system to evaluate the efficacy of topical agents used for dry skin problems objectively and quantitatively.

Adult↗
PubMed1999

Paraquat myopathy: report on two suicide cases.

We describe two suicide cases in which old paraquat was ingested. In conjunction with lung involvement a pronounced degeneration was observed in skeletal muscle of one who died on the 14th day after the ingestion. The following sarcoplasmic or endoplasmic reticulum Ca2+ ATPase (SERCA) monoclonal antibodies were used for skeletal muscle fiber typing by an immunohistochemical method: NCL-SERCA1, reactive with type 2 fiber (fast-twitch), and NCL-SERCA2, reactive with type 1 fiber (slow-twitch). The examination revealed that the remarkably degenerated fibers belonged to type 1 muscle fibers. This case showed an abrupt increase of plasma CK levels (1796 mU/ml) on the fifth day after the ingestion. The authors presume that the damage to the skeletal muscle had occurred in this period. The degeneration of the muscle seemed to be attributable to the long retention of paraquat in the tissue because these findings were not observed in the other case who died on the fifth day. Paraquat-induced myopathy may develop in prolonged paraquat poisoning. The examination of CK levels in plasma will be useful for diagnosis of damage of skeletal muscle.

Aged↗
PubMed1999

A predominant increase of arterial beta-hydroxybutyrate concentration during partial hepatectomies in patients with impaired indocyanine green clearance test.

BACKGROUND: It has been reported that a concentration ratio of two ketone bodies, [acetoacetate]/[beta-hydroxybutyrate], reflects the redox state in the liver mitochondria, but there are few reports which examined each ketone body concentration during hepatectomy. Materials and Methods. (1) Ketone body levels in the radial artery and the hepatic vein were measured simultaneously during hepatectomies in 12 patients. (2) Arterial ketone body levels were measured during hepatectomies (at three points) in 73 patients. RESULTS: (1) Both ketone body levels in the radial artery well reflected those in the hepatic vein (P < 0.001). (2) There was no change in the arterial acetoacetate level. The level of beta-hydroxybutyrate increased significantly from 30.4 to 76.5 micromol/L (P < 0.005) only in the group of 25 patients with seriously impaired indocyanine green clearance test. CONCLUSIONS: Ketosis during hepatectomy was caused by increased beta-hydroxybutyrate, and this phenomenon was observed only in patients with seriously impaired liver function.

3-Hydroxybutyric Acid↗
PubMed1999

Mycobacterium avium infection of the skin associated with lichen scrofulosorum: report of three cases.

We report three Japanese children with Mycobacterium avium infection of the skin who also developed lichen scrofulosorum, a previously undescribed association. They were healthy except for the presence of several noduloulcerative lesions associated with multiple asymptomatic papules on the trunk and extremities. Histology of the ulcerative lesions showed features of mixed-cell granuloma, whereas the papular lesions showed features consistent with lichen scrofulosorum. M. avium was identified by polymerase chain reaction-aided DNA-DNA hybridization analysis in specimens obtained from the noduloulcerative lesions. Both the noduloulcerative and the papular lesions responded well to combination chemotherapy consisting of antituberculous agents and antibiotics.

Anti-Bacterial Agents↗
PubMed1999

Epidemiology and prognosis of plantar melanoma in 62 Japanese patients over a 28-year period.

BACKGROUND: The plantar surface is one of the commonest sites of malignant melanoma in the Japanese; however, the biological behavior is not sufficiently clarified, because of the paucity of long-term studies. We attempted an epidemiologic survey of the cases of plantar melanoma treated in our institute to study the survival rate in the recent period. METHODS: Of the 207 cases of malignant melanoma observed over the past 28 years, 62 patients were diagnosed as having plantar melanoma. The proportion of plantar melanoma to all melanomas, the sex and age of the patients, and the histologic type, stage, and prognosis were evaluated by comparing those registered in the first half (1969-1982) and the second half (1983-1996) of the period. RESULTS: The proportions of plantar melanoma in the first and second half periods were 31% (28 out of 90) and 29% (34 out of 117), respectively. No sex difference in the patients was observed. The mean age of the patients was 67 years. Fifty-one lesions were histologically proven to be acral lentiginous melanoma (ALM), two were superficial spreading melanoma (SSM), and nine were nodular melanoma (NM). Of the nine NMs, eight were registered in the second half period. The heel was affected in 33 (53%), the metatarsal regions in nine (14%), the toes in six (10%), and the arch areas in 14 (23%). The proportion of the weight-bearing areas, including the heel, metatarsal areas, and toes, decreased in the second half period. A comparison of the stages of plantar melanoma showed that, in the first half period, there were 18% of patients with stage IV disease in contrast to none in the second half period. Conversely, the proportion of stage I and II disease was 50% in the second half period, whereas it was only 39% in the first half period. The 5-year survival rates in the first and second half periods were 56% and 71%, respectively. CONCLUSIONS: The prognosis of plantar melanoma has improved recently at our institute. The possible explanation for a trend to better survival in the second half period may be related to a decrease in stage IV disease as well as to an increase in the frequency of diagnosis of early stage disease.

Aged↗
PubMed1999

Nummular eczema: An addition of senile xerosis and unique cutaneous reactivities to environmental aeroallergens.

BACKGROUND: The pathogenesis of nummular eczema (NE) is still unknown. It often develops on the lower legs of elderly individuals with xerotic changes during the winter months. Such winter exacerbation is also observed in atopic dermatitis, in which there is a high incidence of cutaneous immune reactivities against environmental aeroallergens. OBJECTIVE: Because of the total lack of information about skin reactivities in NE patients, we performed immunological as well as functional studies in their uninvolved skin. METHOD: Prick tests and chamber scarification patch tests for representative aeroallergens were conducted on the flexor surface of the forearm in 26 NE patients, in 21 age-matched elderly persons without NE and in 43 healthy young controls. RESULTS: We found that the elderly subjects, regardless of their background, showed a significantly higher immediate skin reactivity to Candida albicans than the young controls. In contrast, patch testing revealed that, unlike the age-matched elderly subjects who showed a decrease in incidence of positive patch test reactions, the NE patients retained delayed contact sensitivity at a level comparable to that of the young healthy controls. They showed a significantly higher percentage of positive patch test reactions to Dermatophagoides farinae allergen (46%) and house dust allergen (35%) than the age-matched controls. Moreover, they also showed a significantly higher percentage of delayed hypersensitive reactions to C. albicans allergen (85%) than the age-matched controls (48%). Noninvasive functional assessment of the stratum corneum (SC) in unaffected skin areas of the lower legs in 8 NE patients demonstrated that, though the water barrier function of the SC was comparable to that of the age-matched controls, they showed a significantly lower hydration state of the SC than the age-matched controls. CONCLUSION: The xerotic skin of elderly individuals facilitates the development of cracking and fissuring of the skin surface in dry and cold winter. Such damage in the SC is sometimes aggravated by inadvertent scratching due to pruritus, allowing skin permeation of various environmental allergens. They may induce eczematous changes in those with preserved adequate delayed hypersensitivity despite their advanced age.

Aged↗
PubMed1999

Ferroverdins, inhibitors of cholesteryl ester transfer protein produced by Streptomyces sp. WK-5344. I. Production, isolation and biological properties.

Streptomyces sp. WK-5344, a soil isolate, was found to produce structurally related inhibitors of cholesteryl ester transfer protein (CETP). New active compounds, designated ferroverdins B and C, were isolated along with known ferroverdin A from the fermentation broth by solvent extraction, ODS column chromatography and silica gel column chromatography. All ferroverdins showed a dose-dependent inhibitory activity against human CETP. The IC50 values were 21, 0.62 and 2.2 microM for ferroverdins A, B and C, respectively, indicating that ferroverdin B is one of the most potent CETP inhibitors of microbial origin.

Bacteria↗