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Biomedical subjects

N Abe

Publications and source records attributed to N Abe.

At least 55 records · Page 3Linked to original sources
PubMed2000

Porphyromonas gingivalis proteinases as virulence determinants in progression of periodontal diseases.

Porphyromonas gingivalis, one of the major causative agents of periodontal diseases, produces large amounts of arginine- and lysine-specific cysteine proteinases in cell-associated and secretory forms, which are now referred to as Arg-gingipain (Rgp) and Lys-gingipain (Kgp), respectively. A number of studies have revealed that these proteinases are closely associated with the periodontopathogenesis of this bacterium: destruction of periodontal connective tissues, disruption of host defense mechanisms, and development and maintenance of inflammation in periodontal pockets. With respect to the physiology of the bacterium, Rgp and Kgp are indispensable for it to obtain nutrients from the environment, since it cannot utilize saccharides as carbon/energy sources for growth and totally depends on peptides and amino acids that are provided from environmental proteins by Rgp and Kgp. Furthermore, proteolytic activities of Rgp and Kgp contribute to processing/maturation of various cell-surface proteins of P. gingivalis, such as fimA fimbrilin (a subunit of major fimbriae), 75-kDa protein (a subunit of minor fimbriae), hemagglutinins, and the hemoglobin receptor protein, which are important for the bacterium to colonize and proliferate in the gingival crevice and to invade the periodontium. These findings strongly indicate critical roles of Rgp and Kgp in the virulence of P. gingivalis.

Adhesins, Bacterial↗
PubMed2000

Design and synthesis of sensitive fluorogenic substrates specific for Lys-gingipain.

Lys-gingipain (Kgp) is a major cysteine proteinase produced by the oral anaerobic bacterium Porphyromonas gingivalis, and has been implicated as a major pathogen in the development and progression of advanced adult periodontitis. This enzyme is believed to act as a major virulence factor of the disease, yet there exist no convenient and sensitive substrates for analyzing its biological activity. For a better understanding of the importance of this enzyme in the organism, there is an urgent need for specific substrates. Here we designed and synthesized two peptide 4-methyl-coumaryl-7-amides (MCA), carbobenzoxy (Z)-His-Glu-Lys-MCA, and Z-Glu-Lys-MCA, and tested their possible use as sensitive substrates for Kgp with limited specificity. Both substrates exhibited greater k(cat)/K(m) values than the best known Kgp substrates described so far. Both substrates were resistant to Arg-gingipain, another pathogenic cysteine proteinase from P. gingivalis, as well as trypsin and cathepsins B, L, and H. The levels of Kgp in various microorganisms and human cells were determined with Z-His-Glu-Lys-MCA. Little or no Kgp-like activity was detected in either other microorganisms or human cells tested. These results indicate that the present substrates are a valuable and fast tool for routine assays and for mechanistic studies on Kgp.

Adhesins, Bacterial↗
PubMed2000

Genomic analysis of Blastocystis hominis strains isolated from two long-term health care facilities.

The genotype Blastocystis hominis is highly polymorphic. Therefore, a genetic marker would be a powerful tool for the identification or classification of B. hominis subtypes and could be used as a means to resolve the transmission route or origin of the parasite. To this end, 32 B. hominis isolates were collected from patients and/or staff members of two long-term health care facilities (facilities A and B), and these organisms were subjected to genotype analysis based on diagnostic PCR primers and restriction fragment length polymorphism (RFLP) of small subunit rRNA gene (rDNA). Based on PCR amplification using diagnostic primers which were developed from randomly amplified polymorphic DNA analysis of known strains of B. hominis, the 32 isolates of B. hominis were classified into three different subtypes. Thirty isolates, including twenty-four that were isolated from patients and a staff member, from facility A and all isolates isolated from six patients from facility B showed the same genotype. Two of six patients of facility B had been transferred from facility A, and these two patients also had the same-genotype B. hominis that corresponded to 24 isolates from facility A. This genotype strain may have been transmitted by these two patients from facility A to facility B, suggesting human-to-human transmission. In contrast, 2 of 26 isolates from facility A showed distinct genotypes, suggesting that the colonization by these two isolates is attributable to another infectious route. These different subtypes were subjected to RFLP analysis, and the RFLP profiles were correlated with the results obtained by diagnostic PCR primers. This study presents the first molecular evidence of possible human-to-human B. hominis infection between and/or among two small communities.

Animals↗
PubMed2000

Properties of NADPH oxidase in specific granule-rich fraction prepared from guinea pig neutrophils.

Both the plasma membrane-rich fraction and specific granule-rich fraction prepared from human neutrophil lysate by Percoll centrifugation have been reported to contain cytochrome b558, a membrane activation factor for NADPH oxidase. In this study, the plasma membrane-rich fraction and specific granule-rich fraction of guinea pig neutrophils were prepared, and the abilities of both fractions to activate NADPH oxidase in a cell-free system consisting of either fraction, cytosol and arachidonate were compared. There was no difference in the Km value for NADPH between NADPH oxidase activated by specific granules or by plasma membranes. Optimum concentrations of arachidonate for the activation of NADPH oxidase in both the fractions were also the same. However, after freeze-thawing, the specific granules markedly lost the ability, compared to plasma membranes. Such instability of specific granules was also observed on hypotonic- or deoxycholate-treatment. The inactivation by freeze-thawing was not suppressed by proteinase inhibitors, and gp91-phox, a large subunit of cytochrome b558, was not degraded by freeze-thawing. Freeze-thawed specific granules did not affect the ability in plasma membranes, indicating the absence of an inactivating factor in specific granules. The increase in the amount of cytosol in the cell-free assay mixture did not compensate for the markedly decreased ability of freeze-thawed specific granules. Translocation of p47-phox, one of the cytosolic activation factors, to specific granules was not affected by freeze-thawing. We found that the ability of specific granules to activate NADPH oxidase was fragile, though it is unclear what is responsible for the instability, at present.

Animals↗
PubMed2000

Determination of left ventricular mass by echocardiography in normotensive diabetic patients.

Patients with Type 2 diabetes mellitus (DM) have excessive cardiovascular morbidity and mortality, even in the absence of hypertension. Left ventricular hypertrophy (LVH), which is an ominous prognostic sign and an independent risk factor for cardiac events, is often present in Type 2 DM patients. Forty-two Type 2 DM patients without hypertension, all of whom had been diagnosed more than 10 years ago, were examined in the present study. They had no evidence of renal dysfunction and had not received any anti-hypertensive drugs. Age-matched healthy normal subjects (n=47) were recruited as controls. All participants were classified according to the left ventricular mass index (LVMI) using M-mode echocardiography and their systolic function (fractional shortening) was examined. The systolic function was not significantly different between the Type 2 DM and control groups. LVH can be seen even in the normotensive Type 2 DM patients, with these patients still having a higher LVMI than the normal control subjects. Although the plasma insulin levels were not significantly increased in the Type 2 DM patients, the LVMI significantly correlated with plasma insulin levels. However, the LVMI did not significantly correlate with plasma fasting glucose and hemoglobin A1c in the Type 2 DM patients. These results suggest that LVH in Type 2 DM patients without hypertension may be associated with elevated plasma insulin levels.

Age Factors↗
PubMed2000

1,1-Diphenyl-2-picrylhydrazyl radical-scavenging compounds from soybean miso and antiproliferative activity of isoflavones from soybean miso toward the cancer cell lines.

Guided by their DPPH radical-scavenging activity, nine compounds were isolated from soybean miso. Of these, 8-hydroxydaidzein, 8-hydroxygenistein and syringic acid had as high DPPH radical-scavenging activity as that of alpha-tocopherol. The antiproliferative activity of four of the isolated isoflavones toward three cancer cell lines was examined. 8-Hydroxygenistein showed the highest activity (IC50=5.2 microM) toward human promyelocytic leukemia cells (HL-60).

Animals↗
PubMed2000

Studies on the 1,1-diphenyl-2-picrylhydrazyl radical scavenging mechanism for a 2-pyrone compound.

The radical scavenging mechanisms for the 2-pyrone compound, 4-hydroxy-3,6-dimethyl-2H-pyrane-2-one (1), and the 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical (4) in several solvent systems were evaluated by the quantitative change in compounds detected at 270 nm and subsequent HPLC analyses. The HPLC profile for each condition suggested that the reaction proceeded by a different mechanism in each solvent system. In organic solvents (CHCl3, iso-propanol, and EtOH), 1-[4-(3,4-dihydro-3,6-dimethyl-2,4-dioxo-2H-pyran-3-yl) phenyl]-1-phenyl-2-picrylhydrazine (2) was produced as an adduct of the DPPH radical and 1. On the other hand, the reaction in a buffer solution (an acetate buffer at pH 5.5) gave several degradation products with 1[4-(2,3-dihydro-2,5-dimethyl-3-oxo-fur-2-yl) phenyl]-1-phenyl-2-picrylhydrazine (5), this being structurally elucidated by spectroscopic analyses. The decrease of the DPPH radical in each reaction system suggests that compound 1 could scavenge about 1.5-1.8 equivalents of the radical in organic solvents and about 3.5-3.9 in the buffer solution.

Bepridil↗
PubMed2000

Novel fungal metabolites, demethylsorbicillin and oxosorbicillinol, isolated from Trichoderma sp. USF-2690.

The novel compounds, demethylsorbicillin (1) and oxosorbicillinol (2), were isolated from a fermentation broth of Trichoderma sp. USF-2690. The structures of these compounds, which were determined from spectroscopic evidence, suggest the possibility that methylation at C-6 and oxidation at C-1 and C-6 of sorbicillin were controlled in the early polyketide stage before the formation of oxidized sorbicillin dimers. In a 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical-scavenging assay, 2 gave an ED50 value of 87.7 microM.

Anti-Bacterial Agents↗
PubMed2000

[Video assisted thoracic surgery for the treatment of catamenial pneumothorax].

Video assisted thoracic surgery (VATS) was applied in 3 cases of pneumothorax combined with pathologic changes in the diaphragm (two cases of catamenial pneumothorax and one case of suspected catamenial pneumothorax). Case 1, 39-year-old woman, was preoperatively diagnosed as catamenial pneumothorax in the right lung. Thoracoscope was inserted through the 5th intercostal anterior axillary line and the lesion with the pathologic changes in the central tendon of the diaphragm was incised and sutured with Endo-GIA and Endo-STAPELAR. Case 2, 42-year-old woman, was confirmed to have pathologic changes in the central tendon after insertion of thoracoscope through the 5th intercostal anterior axillary line. Minithoracotomy of 50 mm in size was added close to the center of the diaphragm and direct incision and suture of that part were performed. Case 3, 47-year-old woman, underwent thoracoscopy through the 5th intercostal mid-axillary line and bulla in the S2 interlobar surface was incised with Endo-GIA. In this case, the diaphragm was partially incised through additional minithoracotomy because some lesions were detected on that part. VATS can fully be carried out for pathologic changes in the diaphragm in catamenial pneumothorax. Since catamenial pneumothorax may be complicated with another pathologic changes in the diaphragm (Case 1) or in the visceral pleura (Case 3), the whole thoracic cavity, including diaphragm and visceral pleura, should be carefully observed under thoracoscopy. Application of minithoracotomy-associated thoracoscopic surgery is a useful method in the case to whom catamenial pneumothorax is definite or suspected.

Adult↗
PubMed1999

Genetic analyses of proteolysis, hemoglobin binding, and hemagglutination of Porphyromonas gingivalis. Construction of mutants with a combination of rgpA, rgpB, kgp, and hagA.

Porphyromonas gingivalis produces arginine-specific cysteine proteinase (Arg-gingipain, RGP) and lysine-specific cysteine proteinase (Lys-gingipain, KGP) in the extracellular and cell-associated forms. Two separate genes (rgpA and rgpB) and a single gene (kgp) have been found to encode RGP and KGP, respectively. We constructed rgpA rgpB kgp triple mutants by homologous recombination with cloned rgp and kgp DNA interrupted by drug resistance gene markers. The triple mutants showed no RGP or KGP activity in either cell extracts or culture supernatants. The culture supernatants of the triple mutants grown in a rich medium had no proteolytic activity toward bovine serum albumin or gelatin derived from human type I collagen. Moreover, the mutants did not grow in a defined medium containing bovine serum albumin as the sole carbon/energy source. These results indicate that the proteolytic activity of P. gingivalis toward bovine serum albumin and gelatin derived from human type I collagen appears to be attributable to RGP and KGP. The hemagglutinin gene hagA of P. gingivalis possesses the adhesin domain regions responsible for hemagglutination and hemoglobin binding that are also located in the C-terminal regions of rgpA and kgp. A rgpA kgp hagA triple mutant constructed in this study exhibited no hemagglutination using sheep erythrocytes or hemoglobin binding activity, as determined by a solid-phase binding assay with horseradish peroxidase-conjugated human hemoglobin, indicating that the adhesin domains seem to be particularly important for P. gingivalis cells to agglutinate erythrocytes and bind hemoglobin, leading to heme acquisition.

Adhesins, Bacterial↗
PubMed1999

Determination of high mobility group I(Y) expression level in colorectal neoplasias: a potential diagnostic marker.

High mobility group I(Y) [HMGI(Y)] proteins are architectural factors abundantly expressed during embryogenesis, and their overexpression is known to be closely associated with neoplastic transformation of cells. This study was performed to investigate whether determination of HMGI(Y) expression level could assist in (a) differential diagnosis between colorectal carcinoma, adenoma, and normal tissue and (b) determination of the prognosis of patients with colorectal cancer. To this end, HMGI(Y) expression was determined at both the protein and mRNA levels in 30 colorectal carcinomas, 26 adenomas, and 23 normal mucosa samples, and further correlations between the protein expression levels and various clinicopathological parameters, such as depth of tumor invasion, lymphatic and/or venous involvement, regional lymph node metastasis, and Dukes' stage, were determined in 30 carcinoma cases. The expression of HMGI(Y) proteins was significantly increased in carcinoma and adenoma with severe atypia compared with that in adenoma with less atypia and normal colorectal mucosa. This increase in HMGI(Y) protein expression was found to be because of an increase in its mRNA expression by RNA in situ hybridization analysis. Clinicopathological analysis revealed that the level of HMGI(Y) protein expression was significantly correlated with parameters known to be indicative of a poor prognosis in colorectal cancer patients. These findings indicate that the determination of the HMGI(Y) protein expression level could be a potential marker for the diagnosis of colorectal neoplasias and can be of great value in predicting the prognosis of patients with colorectal cancer.

Adult↗
PubMed1999

The essential role of phorbol ester-sensitive protein kinase C isoforms in activation-induced cell death of Th1 cells.

Th1 and Th2 cells, which were induced from naive T cells of TCR-transgenic mice, showed differential sensitivity to activation-induced cell death (AICD) triggered by stimulation with anti-CD3 monoclonal antibody. The Th1 cells showed more rapid AICD than Th2 cells. This accelerated AICD of Th1 cells was strongly blocked by protein kinase C (PKC) inhibitors (H-7 or GF 109203X). Moreover, long-term treatment of Th1 cells with phorbol 12-myristate 13-acetate (PMA) caused the abrogation of anti-CD3-induced AICD in parallel with the disappearance of PMA-sensitive PKC isoforms such as PKC alpha, gamma, epsilon and theta. Therefore, it was clearly demonstrated that PMA-sensitive PKC isoforms are essential for AICD of Th1 cells. The different susceptibility to AICD between Th1 and Th2 cells was not due to their differential expression levels of PMA-sensitive PKC isoforms but appeared to be due to their differential requirement for PMA-sensitive isoforms in the up-regulation of Fas ligand which is involved in suicide killing of activated Th1 cells.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1999

Hb Ube-2 in a diabetic case with an abnormally low HbA1C value.

A 69-year-old male diabetic patient had an abnormally low HbA1C value of 2.8%, which was inconsistent with his elevated fasting plasma glucose of 8.2 mmol/l. Hb analysis disclosed that the abnormal Hb was Hb Ube-2 [alpha68 (E17) Asn --> Asp] and it accounted for 21.5% of the total Hb. Since the glycated abnormal Hb emerged at the same position as did HbF on high performance liquid chromatography, the HbA1C value was falsely low. The present case demonstrates that Hb Ube-2 is one of the abnormal Hbs in which caution should be exercised when monitoring diabetic control.

Aged↗
PubMed1998

Arg-gingipain acts as a major processing enzyme for various cell surface proteins in Porphyromonas gingivalis.

Arg-gingipain (RGP) is an Arg-X-specific cysteine proteinase produced by the Gram-negative anaerobe Porphyromonas gingivalis and has been shown to be a potent virulence factor in progressive periodontal disease (Nakayama, K., Kadowaki, T., Okamoto, K., and Yamamoto, K. (1995) J. Biol. Chem. 270, 23619-23626). In this study, we provide evidence that RGP acts as a major processing enzyme for various cell surface and secretory proteins in P. gingivalis. Fimbrilin, a major component of fimbriae, remained in the precursor form in the RGP-null mutant. Prefimbrilin expressed in Escherichia coli was converted to the mature fimbrilin in vitro when incubated with purified RGP, but its conversion was suppressed by potent RGP inhibitors. The results were consistent with the electron microscopic observation indicating little or no fimbriation in the RGP-null mutant. The immunogenic 75-kDa cell surface protein was also shown to retain its proform in the RGP-null mutant. In addition, Lys-gingipain (KGP) was found to be abnormally processed in the RGP-null mutant. In contrast, both prefimbrilin and the 75-kDa protein precursor were processed to their respective mature forms in the KGP-null mutant, suggesting that KGP is not involved in the normal processing mechanisms of these proteins. These results suggest that RGP not only acts as a direct virulence factor but also makes a significant contribution as a major processing enzyme to the virulence of P. gingivalis.

Adhesins, Bacterial↗
PubMed1998

Involvement of a lysine-specific cysteine proteinase in hemoglobin adsorption and heme accumulation by Porphyromonas gingivalis.

The oral anaerobic bacterium Porphyromonas gingivalis, a major pathogen of advanced adult periodontitis, produces a novel class of cysteine proteinases in both cell-associated and secretory forms. A lysine-specific cysteine proteinase (Lys-gingipain, KGP), as well as an arginine-specific cysteine proteinase (Arg-gingipain), is a major trypsin-like proteinase of the organism. Recent studies indicate that the secreted KGP is implicated in the destruction of periodontal tissue and the disruption of host defense mechanisms. In this study, we have constructed a KGP-deficient mutant to determine whether the cell-associated KGP is important for pathophysiology of the organism. Although the mutant retained the strong ability to disrupt the bactericidal activity of polymorphonuclear leukocytes, its hemagglutination activity was reduced to about one-half that observed with the wild-type strain. More important, the mutant did not form black-pigmented colonies on blood agar plates, indicating the defect of hemoglobin adsorption and heme accumulation. Immunoblot analysis showed that the expression of a 19-kDa hemoglobin receptor protein, which is thought to be responsible for hemoglobin binding by the organism, was greatly retarded in this mutant. The mutant also showed a marked decrease in the ability to degrade fibrinogen. These results suggest the possible involvement of KGP in the hemoglobin binding and heme accumulation of the organism and in the bleeding tendency in periodontal pockets.

Adhesins, Bacterial↗
PubMed1998

Accumulation of IL-12-activated antitumor effector cells into lymph nodes of tumor-bearing mice.

Simultaneous administration of high dose of IL-12 into tumor-inoculated mice resulted in a marked reduction of tumor growth in parallel with the augmented generation of cytotoxic T-cells, natural killer (NK) cells and IFN-gamma-producing Th cells. We found that these IL-12-activated antitumor effector cells preferentially accumulated in peripheral lymph nodes concomitantly with lymphadenopathy. However, IL-12 rather induced disappearance of antitumor effector cells including CD4+ T, CD8+ T and NK cells from spleen in spite of inducing splenomegaly. Lymph node cells obtained from IL-12-treated B16F0-bearing mice showed a marked IFN-gamma production in response to not only IL-2, IL-12, anti CD3 mAb but also B16F0 melanoma cells. Moreover, they could lyse B16F0 melanoma cells in a long-term cytotoxicity assay. It was also confirmed that IL-12-activated IFN-gamma producing Th1 cells were accumulated in tumor local site. Thus, IL-12 appeared to have a capability of stimulating selective migration of antitumor cells into lymph nodes and tumor local sites.

Animals↗
PubMed1998

Cross-sectional area measurement of the semitendinosus tendon for anterior cruciate ligament reconstruction.

We measured the cross-sectional area (CSA) of the semitendinosus tendon (SMT) in 79 anterior cruciate ligament (ACL)-injured patients using magnetic resonance imaging (MRI) to scrutinize their appropriateness for ACL grafts. Measurements of the CSAs of the SMT with MRI were closely correlated with intraoperative direct measurement (y = 0.697). The mean CSAs of the SMT measured with MRI ranged from 6.3 to 15.0 mm2 with a mean of 10.1+/-2.1 mm2. The CSA of the SMT measured with MRI proved to be a useful indicator to determine preoperatively whether the SMT graft would be of adequate dimensions (7 mm or more in diameter, 60 mm or more in length) for ACL reconstruction. If the CSA of the SMT was more than 11 mm2, a sufficiently thick and long graft could be prepared with a tripled or quadrupled SMT in 89% of cases. We conclude that tissue CSA measurements using MRI could potentially be implemented as a useful tool for determining the most appropriate donor autograft tissue preoperatively, thus minimizing harvest-site morbidity.

Adolescent↗