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Biomedical subjects

S Sugai

Publications and source records attributed to S Sugai.

At least 37 records · Page 2Linked to original sources
PubMed2000

4-Sulfenyl-2-carbamoyl-4-isoxazolin-3-ones: biological isostere to 4-chloro-2-carbamoyl-4-isoxazolin-3-ones.

4-Sulfenyl-2-carbamoyl-4-isoxazolin-3-ones (4) were designed on the basis of biological isosterism and prepared in four steps. Some of these compounds showed sufficient pre-emergent herbicidal activities against various kinds of weeds. Among the synthesized compounds, 2-(N-(4-chlorophenyl)-N-isopropylcarbamoyl)-4-ethylthio-5-methyl-4 -isoxazolin-3-one (4cd) exhibited the most promising activity.

Carbamates↗
PubMed2000

[Histiocytic necrotizing lymphadenitis (Kikuchi-Fujimoto's disease) accompanied by hemophagocytosis and salivary gland swelling in a patient with systemic lupus erythematosus].

After 2 years of steroid therapy that had effectively controlled her systemic lupus erythematosus, a 37-year-old woman presented with fever, erythema (face, upper chest), and low CH50. Increased oral steroid (prednisolone from 15 mg to 40 mg) and intravenous methylprednisolone (mPSL) (80 mg for 3 days) alleviated these symptoms except for the fever. Subsequently, the patient's fever worsened and leukocytopenia, abnormal liver function, lymphadenopathy (neck, axilla), and salivary gland swelling developed. Lymph node histology revealed features characteristic of Kikuchi-Fujimoto's disease (KFD). Laboratory examinations showed WBC 600/microliter, Hb 9.5 g/dl, platelets 90,000/microliter, GOT 766 IU/l, GPT 646 IU/l, LDH 4,228 IU/l, TG 1,622 mg/dl, and ferritin 6,330 ng/ml. Serum interferon gamma was also elevated (673 U/ml). Because a bone marrow smear revealed hemophagocytosis, mPSL pulse therapy (1 g for 3 days) was started for treatment of hemophagocytic syndrome. The fever promptly disappeared, and the patient's clinical symptoms resolved within 2 weeks. The abnormal laboratory data related to KFD and hemophagocytosis returned to normal within 4 weeks after the initiation of mPSL pulse therapy. We speculated that the hemophagocytosis and salivary gland involvement in this patient were also symptoms of KFD. This case indicated that corticosteroid pulse therapy is effective for KFD with serious clinical symptoms.

Adult↗
PubMed1999

Expression of a dominant negative SHP-2 in transgenic mice induces insulin resistance.

To elucidate the roles of SHP-2, we generated transgenic (Tg) mice expressing a dominant negative mutant lacking protein tyrosine phosphatase domain (DeltaPTP). On examining two lines of Tg mice identified by Southern blot, the transgene product was expressed in skeletal muscle, liver, and adipose tissues, and insulin-induced association of insulin receptor substrate 1 with endogenous SHP-2 was inhibited, confirming that DeltaPTP has a dominant negative property. The intraperitoneal glucose loading test demonstrated an increase in blood glucose levels in Tg mice. Plasma insulin levels in Tg mice after 4 h fasting were 3 times greater with comparable blood glucose levels. To estimate insulin sensitivity by a constant glucose, insulin, and somatostatin infusion, steady state blood glucose levels were higher, suggesting the presence of insulin resistance. Furthermore, we observed the impairment of insulin-stimulated glucose uptake in muscle and adipocytes in the presence of physiological concentrations of insulin. Moreover, tyrosine phosphorylation of insulin receptor substrate-1 and stimulation of phosphatidylinositol 3-kinase and Akt kinase activities by insulin were attenuated in muscle and liver. These results indicate that the inhibition of endogenous SHP-2 function by the overexpression of a dominant negative mutant may lead to impaired insulin sensitivity of glucose metabolism, and thus SHP-2 may function to modulate insulin signaling in target tissues.

Animals↗
PubMed1999

Absence of genetic alteration at codon 531 of the human c-src gene in 479 advanced colorectal cancers from Japanese and Caucasian patients.

Activation of c-src, a cellular human gene homologous in sequence to the v-src gene of Rous sarcoma virus, had been thought to play an important role in the progression of several types of human cancers, without having undergone any genetic changes. However, recently truncating mutations at codon 531 of the c-src gene were reported in 12% of the advanced colon cancers, and it was also demonstrated that this change was activating, transforming, tumorigenic, and metastasis promoting. To investigate whether the codon 531-specific mutation could be involved in the carcinogenesis of colorectal cancer in the Japanese and Caucasian populations, we examined a total of 479 advanced colorectal cancers from 421 Japanese patients (46 of them with liver or lung metastases) and from 58 Caucasian patients (11 of them with liver metastases). Using the PCR-RFLP assay and additional single-strand conformation polymorphism analysis, we detected no genetic alteration in any of the advanced colorectal cancers. Our results suggest that the codon 531-specific mutational activation of c-src is unlikely to play a significant role in the malignant progression of colorectal cancers among most Japanese and Caucasian patients.

Asian People↗
PubMed1999

Folding-unfolding equilibrium and kinetics of equine beta-lactoglobulin: equivalence between the equilibrium molten globule state and a burst-phase folding intermediate.

The denaturant-induced equilibrium unfolding transition of equine beta-lactoglobulin was investigated by ultraviolet absorption, fluorescence, and circular dichroism (CD) spectra. An equilibrium intermediate populates at moderate denaturant concentrations, and its CD spectrum is similar to that of the molten globule state previously observed for this protein at acid pH [Ikeguchi, M., Kato, S., Shimizu, A., and Sugai, S. (1997) Proteins: Struct., Funct., Genet. 27, 567-575]. The unfolding and refolding kinetics were also investigated by the stopped-flow CD and fluorescence. A significant change in the CD intensity was observed within the dead time of measurements (25 ms) when the refolding reaction was initiated by diluting the urea-unfolded protein solution, indicating the transient accumulation of the folding intermediate. The CD spectrum of this burst-phase intermediate agrees well with that of the molten globule state at acid pH. The stability of the burst-phase intermediate was also estimated from the urea-concentration dependence of the burst-phase amplitude, and it shows a fair agreement with that of the equilibrium intermediate. These results indicate that the molten globule state of equine beta-lactoglobulin populates at moderate urea concentration as well as at acid pH and it is equivalent with the kinetic folding intermediate.

Animals↗
PubMed1999

Association of the glutathione S-transferase M1 homozygous null genotype with susceptibility to Sjögren's syndrome in Japanese individuals.

OBJECTIVE: To investigate the role of polymorphisms of the glutathione S-transferase M1 (GSTM1) and GSTT1 genes in determining susceptibility to Sjögren's syndrome (SS) and autoantibody production. METHODS: Polymorphisms of the GSTM1 and GSTT1 genes in 106 Japanese patients with primary SS and in 143 healthy controls were analyzed by polymerase chain reaction. RESULTS: Frequency of the GSTM1 homozygous null genotype was significantly increased in SS patients compared with controls (57.5% versus 44.1%; P = 0.035). Moreover, a significantly greater frequency of SSA antibodies was found among SS patients with the GSTM1 null genotype than among those with the GSTM1 non-null genotype (P = 0.0013). Frequency of the GSTT1 polymorphism was not different between SS patients and controls. CONCLUSION: The GSTM1 homozygous null genotype could be a genetic factor that determines susceptibility to SS and may be involved in SSA antibody production.

Adult↗
PubMed1999

Expression of tumor necrosis factor-alpha and interleukin-6 in oral squamous cell carcinoma.

To explore the role of cytokines in tumor development and clinical manifestations, we examined the expressions of tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6) in tumor tissues obtained from 57 patients with oral squamous cell carcinoma (OSCC) and their relationships to pathological grade and staging. Enzyme-linked immunosorbent assay on the tumor tissues demonstrated elevated concentrations of TNF-alpha and IL-6 proteins and upregulated mRNA levels were detected by the reverse transcription-polymerase chain reaction method when compared to those in normal control tissues. These cytokines and their transcripts were localized in stromal macrophages and in the tumor cells in particular of the front area of tumor tissues, possibly indicating active synthesis of these cytokines by tumor cells. Larger-sized tumors (T3, 4) contained significantly greater levels of IL-6 proteins than small-sized tumors (T1, 2) (P<0.05). The levels of these cytokines were significantly reduced in cases with effective pre-treatment with radiation or anti-cancer agents compared to those in the less effective group (P<0.05, grade IIa vs. grade IV for both TNF-alpha and IL-6). The present study thus demonstrated enhanced expression of cytokines in OSCC tissues.

Carcinoma, Squamous Cell↗
PubMed1999

[Evaluation of the histologic criteria for the diagnosis of Sjögren's syndrome].

OBJECTIVE: The most important diagnostic criterion in Sjögren's syndrome (SS) is considered to be the histologic focus score of the labial salivary glands. The focus score is defined as the number of lymphocytic foci per 4 mm2 of the salivary gland according to the criterion of Chisholm & Mason. On the other hand, in the criteria of the Sjögren's Disease Research Committee of the Ministry of Health and Welfare in Japan it is defined as the number of lymphocytic foci per a lobule of the salivary gland. By setting the limited criteria for SS on the basis of objective signs of both dry eyes and dry mouth, we compared the usefulness of these two diagnostic criteria for the diagnosis of SS in terms of the sensitivity, the specificity and laboratory data. METHODS: The biopsy of labial salivary glands was performed in 245 patients (230 females and 15 males, with a mean age of 54.9 years) who were suspected of SS in our hospital during the time between 1975 and 1996. Labial salivary glands were histologically assessed and the focus score was calculated according to the criterion of Chisholm & Mason and to that of the Sjögren's Disease Research Committee, respectively. RESULTS: The average area per a lobule of the salivary gland was 0.70 mm2. According to the limited criteria for SS, the Japanese histologic diagnostic criteria showed a higher specificity (93.3%) and a lower sensitivity (23.5%). The sensitivity of the criterion of Chisholm & Mason was 72.1%, and the specificity was 80.0%. The margin of the lobule was sometimes difficult to be identified because of the fatty change and fibrosis in some salivary glands. CONCLUSIONS: By comparing the two different histologic criteria using our limited criteria, it was better to use the histologic criterion of Chisholm & Mason as a criterion for the diagnosis of SS than that of the Sjogren's Disease Research Committee of the Ministry of Health and Welfare in Japan in terms of the sensitivity, the specificity and laboratory data.

Adult↗
PubMed1999

Epstein-Barr virus study in malignant lymphoma in Sjögren's syndrome.

The association of Epstein-Barr virus (EBV) with Sjögren's syndrome (SS) is controversial. Reports suggest there is an increased risk of developing lymphoid malignancy in SS. Among our 425 cases of SS, 17 cases of malignant lymphoma (4%), 16 cases of non-Hodgkin's lymphoma (NHL), and 1 case of Hodgkin's disease were found. We looked for an association between EBV and 14 cases of NHL, 13 cases of B-cell lymphoma, and 1 case of T-cell lymphoma in which tissue specimens were available. Epstein-Barr virus-encoded RNA in situ hybridization study and polymerase chain reaction (PCR) study using primers to detect the Bam HI W fragment of EBV with DNA extracts were positive in 2 NHLs: 1 diffuse, large B-cell-type lymphoma, 1 out of 13 cases (8%) of B-cell lymphoma, and 1 angioimmunoblastic T-cell lymphoma with dysproteinemia. In the Bam HI W PCR study of DNA obtained from the labial small salivary glands of 55 cases with SS, 3 cases (5%) were positive. These 3 cases were not associated with malignant lymphoma. Our study revealed that EBV association in SS did not lead to an increased occurrence.

Aged↗
PubMed1998

Transition state in the folding of alpha-lactalbumin probed by the 6-120 disulfide bond.

The guanidine hydrochloride concentration dependence of the folding and unfolding rate constants of a derivative of alpha-lactalbumin, in which the 6-120 disulfide bond is selectively reduced and S-carboxymethylated, was measured and compared with that of disulfide-intact alpha-lactalbumin. The concentration dependence of the folding and unfolding rate constants was analyzed on the basis of the two alternative models, the intermediate-controlled folding model and the multiple-pathway folding model, that we had proposed previously. All of the data supported the multiple-pathway folding model. Therefore, the molten globule state that accumulates at an early stage of folding of alpha-lactalbumin is not an obligatory intermediate. The cleavage of the 6-120 disulfide bond resulted in acceleration of unfolding without changing the refolding rate, indicating that the loop closed by the 6-120 disulfide bond is unfolded in the transition state. It is theoretically shown that the chain entropy gain on removing the cross-link from a random coil chain with helical stretches can be comparable to that from an entirely random chain. Therefore, the present result is not inconsistent with the known structure in the molten globule intermediate. Based on this result and other knowledge obtained so far, the structure in the transition state of the folding reaction of alpha-lactalbumin is discussed.

Animals↗
PubMed1998

Dissemination of Epstein-Barr virus associated B-cell lymphoma of the brain after development of immunological incompetence with Evans syndrome.

A 54-year-old female with Epstein-Barr virus (EBV)-associated B-cell lymphoma of the brain and Evans syndrome is presented. After treatment of the lymphoma with irradiation to the brain and chemotherapy she developed Evans syndrome with autoimmune hemolytic anemia and thrombocytopenia. Further immunosuppressive treatment for Evans syndrome caused the dissemination of EBV-associated B-cell lymphoma. The dissemination of EBV-associated B-cell lymphoma was confirmed by in situ hybridization with EBV encoded small RNAs (EBER), polymerase chain reaction with Bam HI-W fragment of EBV and lymphocyte determined membrane antigen (LYDMA) and immunohistochemistry with latent membrane protein (LMP). Since only a few cases of lymphomas associated with EBV occurring during autoimmune diseases have been reported, this is an illustrative case.

Autoimmune Diseases↗
PubMed1998

Determination of Epstein-Barr virus association with B-cell lymphomas in Japan: study of 72 cases--in situ hybridization, polymerase chain reaction, immunohistochemical studies.

The association of Epstein-Barr virus (EBV) with B-cell lymphoma was examined in 72 human immunodeficiency virus-negative Japanese patients using the polymerase chain reaction (PCR) on DNA obtained from formalin-fixed paraffin-embedded tissues and an in situ hybridization (ISH) technique. EBV-encoded RNA 1 (EBER-1) was detected in 12 of 72 cases (17%); five of 33 cases (15%) of nodal B-cell lymphomas and seven of 39 cases (18%) of extranodal B-cell lymphomas. Three cases of post-bone marrow transplantation and one case of autoimmune disease (Evans syndrome) were included among seven EBER-1 positive extranodal lymphomas. A combined study of immunohistochemistry and EBER-1 revealed that some L26 positive cells were EBER-1 positive. A DNA band was also observed in 13 of 70 examined cases (19%) (four of 33 cases of nodal B-cell lymphomas (12%) and nine of 37 cases of extranodal B-lymphomas (24%)) in the PCR study using primers to detect the Bam HI-W fragment of EBV. In the immunohistochemical study using a monoclonal antibody to the latent membrane protein 1 (LMP-1) of the EBV, one of the EBV-encoded latent gene products, LMP-1, was expressed in six of 34 cases (18%) of extranodal B-lymphomas, but none of the cases with nodal B-cell lymphomas were shown to be LMP-1 positive. Oncoprotein bcl-2 was examined by immunohistochemistry and found to be expressed in seven cases of nodal lymphomas and three cases of extranodal lymphomas, and two of these nodal cases were EBER ISH positive. In EBV serology, only two cases of nodal and one case of extranodal EBER positive B-cell lymphomas revealed a reactivation pattern. In the PCR study using primers to detect the lymphocyte-determined membrane antigen (LYDMA), the same sized monoclonal bands were observed in case 36 in the PCR products from the nose and skin, suggesting the monoclonal proliferation of the tumor. These findings suggested a low incidence of EBV association with B-cell lymphomas unless patients were in an immunologically impaired condition such as post-organ transplantation or autoimmune diseases.

Adult↗