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Biomedical subjects

K Maeda

Publications and source records attributed to K Maeda.

At least 685 records · Page 38Linked to original sources
PubMed1995

Pathogenesis of dialysis-related amyloidosis.

Beta 2-microglobulin has been demonstrated to be a major constituent of amyloid fibrils in dialysis-related amyloidosis. However, the molecular pathogenesis of this complication remains unknown. Several lines of evidence suggest that beta 2-microglobulin is not an innocent bystander, but plays an active role in the development of dialysis-related amyloidosis. The evidence remains inconclusive, however, as to whether it is intact or modified beta 2-microglobulin which is amyloidogenic and contributes to bone and joint destruction. Recent biochemical and immunohistological studies have revealed a new modification of beta 2-microglobulin in amyloid fibrils, the advanced glycation end products formed nonenzymatically between aldoses and proteins. Further study has suggested that the interaction of advanced glycation end product-modified beta 2-microglobulin with monocytes/macrophages gives a plausible, albeit incomplete, explanation for the mechanism of bone and joint destruction in dialysis-related amyloidosis. This review focuses on new aspects of the pathogenesis of dialysis-related amyloidosis.

Amyloid beta-Peptides↗
PubMed1995

Natural killer (NK)-like cytotoxicity of murine intraepithelial lymphocytes in the small intestine (iIEL) and the effect of the serine proteases.

The natural killer (NK)-like cytotoxicity of murine intraepithelial lymphocytes in the small intestine (iIEL) and the participation of serine proteases in it were investigated. We monitored the cytotoxicity of iIEL with a sensitive cytotoxic assay using laser flow cytometry. iIEL exhibited NK-like cytotoxicity on YAC-1 target cells. Benzamidine, a serine protease inhibitor, inhibited significantly both Na-CBZ-L-lysine thiobenzyl ester (BLT)-specific serine protease activity and iIEL-mediated NK-like cytotoxicity. These results suggest that BLT-specific serine proteases may participate in NK-like cytotoxicity of murine iIEL.

Amino Acid Sequence↗
PubMed1995

N-acetyltransferase activity in the urine in Japanese subjects: comparison in healthy persons and bladder cancer patients.

The activity of urinary N-acetylamino-transferase was determined by high-performance liquid chromatographic assay of acetylisoniazid and isoniazid after administration of isoniazid to healthy Japanese male and bladder cancer patients in Japan. The healthy subjects were 47 college students and 44 company employees ranging from 18 to 64 years old (mean +/- SC = 34.5 +/- 13.7). The bladder cancer group consisted of 58 male and 13 female patients, ranging from 28 to 82 years old (mean +/- SD = 60.8 +/- 11.6), who were being treated at several hospitals. The slow phenotype, defined as an acetylation ratio (acetylisoniazid/isoniazid) of less than 2.0, was observed in 13 (14.3%) of the 91 healthy subjects, and in 20 (28.2%) of the 71 bladder cancer patients; the difference between the two groups is significant (p < 0.05). A histogram of the acetylation ratio values showed an overall leftward shift of the patient group, indicating low values of acetylation ratio in this group as a whole (p < 0.01).

Acetylation↗
PubMed1995

Colorimetric microtiter plate based assay for detection and quantification of amplified Actinobacillus actinomycetemcomitans DNA.

We developed a colorimetric microtiter plate-based assay for the detection and quantification of polymerase chain reaction-amplified DNA fragment specific for Actinobacillus actinomycetemcomitans. We amplified the 396-bp leukotoxin-specific DNA fragment by using two oligonucleotide primers, one carrying a biotin group at the 5' end and another one with a digoxigenin at the 5' end. Following amplification, the biotinylated polymerase chain reaction products were applied to a microtiter well precoated with avidin. The colorimetric detection and quantification were achieved by an enzyme-linked immunosorbent assay using alkaline phosphatase-conjugated anti-digoxigenin antibody. The detection limit of the colorimetric assay was found to be as little as 500 fg of purified A. actinomycetemcomitans DNA and as few as 50 A. actinomycetemcomitans. Therefore, this colorimetric assay was able to estimate the amount of A. actinomycetemcomitans in subgingival plaque samples. We concluded that the colorimetric assay of the PCR product is a very useful method not only to detect the presence of A. actinomycetemcomitans but also to quantify the amount of A. actinomycetemcomitans in large numbers of subgingival plaque samples.

Aggregatibacter actinomycetemcomitans↗
PubMed1995

Effects of antidepressants on thyroid stimulating hormone release in rats under ether stress.

We found inhibitory effects of antidepressants (clomipramine, maprotyline, mianserin and zimelidine) and 5-hydroxytryptophan (5-HTP) on thyroid stimulating hormone (TSH) release induced by ether stress in freely moving rats. We confirmed that ether stress suppressed the plasma TSH levels after 30 min. We then injected intravenously 250 ng thyrotropin releasing hormone (TRH), 0.1 mg/kg clomipramine, 2.5 mg/kg maprotyline, 2.5 mg/kg mianserin, 0.5 mg/kg zimelidine and 25 mg/kg 5-HTP simultaneously. These materials blocked the influences on plasma TSH levels by the ether stress. Serotonergic antidepressants (clomipramine, zimelidine) and 5-HTP (precursor of serotonin) had a higher potency against the ether stress. These results suggest that antagonizing effects against the ether stress may involve the serotonergic system in the pituitary gland.

5-Hydroxytryptophan↗
PubMed1995

Lipopolysaccharides from periodontal pathogens prime neutrophils for enhanced respiratory burst: differential effect of a synthetic lipid a precursor IVA (LA-14-PP).

When neutrophils are incubated with bacterial lipopolysaccharide (LPS), they become primed for enhanced release of superoxide anion (O2-) in response to stimulation by FMLP. We investigated the human neutrophil-priming activity of LPS from the periodontal pathogens, Porphyromonas gingivalis (Pg), Prevotella intermedia (Pi) and Actinobacillus actinomycetemcomitans (Aa) in comparison with that of LPS from Escherichia coli (E. coli). The optimum conditions for LPS to prime neutrophils were assessed for every LPS and found to be as follows: Neutrophils were incubated with LPS in the presence of 10% heat-inactivated plasma and 1 mM EDTA at 37 degrees C for 30 min and then stimulated with 1 microM FMLP at 37 degrees C for 7 min. Under these conditions, half-maximum priming was observed at 6.2 ng/ml Pg-LPS, 45 ng/ml Pi-LPS, 1.5 ng/ml Aa-LPS and 1.5 ng/ml E. coli-LPS. The priming activity of each LPS was neutralized by polymyxin B. Anti-CD14 monoclonal antibody inhibited priming by all LPS. The priming by Aa-LPS and E. coli-LPS was inhibited by LA-14-PP, a synthetic lipid A precursor IVA, but that by Pg-LPS and Pi-LPS was not. Priming by tumor necrosis factor alpha was not affected by polymyxin B, anti-CD14 antibody or LA-14-PP. Gelation of Limulus amebocyte lysate occurred at 10 pg/ml Pg-LPS, 30 pg/ml Pi-LPS, 3 pg/ml Aa-LPS and 3 pg/ml E. coli-LPS. Thus LPS from different periodontal pathogens primed neutrophils with different efficacy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aggregatibacter actinomycetemcomitans↗
PubMed1995

[A case of sepsis due to Escherichia coli isolated from blood, transtracheal aspiration and urine].

We reported a 53-year-old female who was admitted due to partial loss of consciousness. She had been diagnosed as old pulmonary tuberculosis and diabetes mellitus. She was diagnosed as diabetic keto-acidosis on admission. We isolated Escherichia coli in the blood, transtracheal aspiration (TTA) and from the urine. We have experienced 6 cases where the same bacteria was isolated from the blood and TTA at the same time. In all 6 cases, we have found single bacteria in the blood and a few other bacteria in TTA. Blood culture is the most certain method to detect the origin of infectious diseases. But the compromised host, as in this case, has multifocal infections in many cases. In order to understand the pathological aspects of the infection, we must obtain many kinds of samples and as many as possible.

Blood↗
PubMed1995

[Determination of the neutrophil function in the respiratory infection by chemiluminescence (CL). III: Changes in neutrophil and whole blood CL after chemotherapy against the acute respiratory infection].

We measured the chemiluminescent activity (CL-index) in both the whole blood and isolated neutrophils from 12 patients with acute respiratory infection (7 cases; pneumonia, 4 cases; in the exacerbated phase, chronic lower tract infection, and one; acute bronchitis) two times per each case: before and after chemotherapy. Before the initiation of chemotherapy, neutrophil and whole blood CL was high but whole blood CL was higher. After the completion of chemotherapy, whole blood CL was decreased more significantly than neutrophil CL. There was no correlation between neutrophil CL and whole blood CL. However the neutrophil CL-index.N (neutrophil numbers x neutrophil CL-index) was correlated with the whole blood CL. Thus, we think the number of neutrophils is a critical factor for phagocytic function of neutrophils as determined by CL.

Acute Disease↗
PubMed1995

Restriction endonuclease analysis of field isolates of feline herpesvirus type 1 and identification of heterogeneous regions.

The genomic heterogeneity of 78 isolates of feline herpesvirus type 1 (FHV-1) recently isolated from cats suspected to have feline viral rhinotracheitis was analyzed by examining the digestion patterns found with restriction endonuclease MluI. The FHV-1 field isolates were classified into at least three genotypes, namely, the C7301, F2 (an attenuated vaccine strain), and C7805 types. The C7301 type seems to be a major type, since 64 of the 78 isolates belonged to this type. Eight and six isolates belonged to the F2 and C7805 types, respectively. Compared with the C7301 type, the heterogeneous region of the F2 type was localized to a 4.3-kbp EcoRI fragment within the US segment and the heterogeneous region of the C7805 type was localized to a 5.5-kbp XbaI fragment within the UL segment. Northern (RNA) blot analysis revealed no differences in the products transcribed from these regions. In addition, nucleotide sequence analysis showed that the MluI sites not found in the F2 and C7805 types were located in the regions homologous to the herpes simplex virus type 1 gI and UL5 genes, respectively.

Animals↗
PubMed1995

Factor(s) present in sera from patients on long-term hemodialysis increase(s) mRNAs for collagenase and stromelysin in synovial cells.

Rheumatic disorders are common complications in patients on long-term hemodialysis (HD), and abnormalities of collagen metabolism in the musculoskeletal system have been suggested in these patients. Since collagenase, which catalyzes the initial step in the proteolytic degradation of collagen, plays an important role in the metabolism of collagen, the present study investigated whether factor(s) present in the sera from patients on long-term HD stimulates collagenase gene expression in synovial cells. The addition of sera from 8 patients on long-term HD resulted in 1.5- to 4.0-fold increases in the collagenase mRNA level in human synovial cells as compared with that of sera from normal subjects. The collagenase-inducing factor(s) in uremic sera is more than 3,000 D in molecular mass and shows no binding to heparin. Uremic sera also increased stromelysin mRNA, but failed to exert any effect on mRNAs for tissue inhibitor of metalloproteinases and pro alpha 1(I)collagen. Our findings suggest that there exists a factor(s) to enhance degradation of synovial collagen in sera from long-term HD patients.

Cells, Cultured↗
PubMed1995

Interleukin 8 and biocompatibility of dialysis membranes.

To determine whether interleukin 8 (IL-8) can be used as an index of biocompatibility of dialysis membranes, the effects of hemodialysis (HD) on plasma IL-8 levels and the expression of IL-8 mRNA in peripheral blood mononuclear cell (PBMC) were compared among regenerated cellulose (RC), polyacrylonitrile (PAN) and polymethylmethacrylate (PMMA) dialyzers. HD using RC dialysers significantly increased plasma IL-8 levels and induced abundant expression of IL-8 mRNA in PBMC. HD using PMMA dialyzers also increased plasma IL-8 levels and induced slight expression of IL-8 mRNA. In contrast, HD using PAN dialyzers neither increased plasma IL-8 levels nor induced the expression of IL-8 mRNA. In vitro studies demonstrated that IL-8 was considerably adsorbed by PAN membranes and not at all by RC and PMMA. These studies indicate that plasma IL-8 level and expression of PBMC IL-8 mRNA can be used as indices of biocompatibility of dialysis membranes.

Acrylic Resins↗
PubMed1995

Elevated serum levels of 3-deoxyglucosone, a potent protein-cross-linking intermediate of the Maillard reaction, in uremic patients.

3-Deoxyglucosone (3-DG) has been identified as an intermediate of the Maillard reaction in vitro. We measured serum 3-DG levels using gas chromatography/mass spectrometry and found a marked elevation in serum 3-DG levels in uremic patients compared with healthy subjects. The uremic patients with diabetes showed significantly higher serum concentrations of 3-DG than those without diabetes. 3-DG was demonstrated to be a potent protein-cross-linking agent in the reaction with lysozyme, leading to browning, fluorescence formation and polymerization of the protein by formation of advanced glycation end products (AGE). The increase in serum 3-DG levels in the uremic patients suggests that 3-DG may be responsible for the development of uremic complications by promoting the formation of AGE.

Adult↗
PubMed1995

Observation of T cell surface antigens in the clinical course of adult T-cell leukemia: case report of a spontaneous remission.

A patient with acute adult T-cell leukemia (ATL) in whom spontaneous remission was observed without any specific treatment having been given is described. The abnormal cell phenotype was CD4+, CD45RO+ and CD8-. As the number of abnormal cells decreased, CD4+ cell count decreased and CD8+ cells and CD45RA+ cells increased to normal levels (45 and 77%, respectively). Further, the number of cells with CD45RO antigen of intermediate fluorescence intensity increased. Five months after admission, we assessed the patient as being in a state of complete clinical remission; no abnormal cells were detected in peripheral blood, lymph node enlargement had disappeared and the serum chemistry was normal. When the abnormal cells in peripheral blood had disappeared, Southern blot analysis for HTLV-I proviral DNA still revealed a weak monoclonal band with EcoRI digestion, and HTLV-I proviral DNA was detected by polymerase chain reaction analysis. Thus, it appeared that very few abnormal cells persisted although the laboratory findings for ATL were normal. Our case could contribute to the understanding of the mechanism that underlies spontaneous remission in ATL.

Adult↗