States of imino groups in pepsin measured by the reactivity with tertiary-butylhypochlorite.
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Biomedical subjects
Publications and source records attributed to T Hosoi.
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Mouse macrophage galactose/N-acetylgalactosamine-specific calcium-type lectin (mMGL) has a calcium-dependent conformational epitope which is a ligand-induced binding site. A monoclonal antibody (mAb) specific for this epitope (LOM-11) stabilize lectin activity. We performed mapping for this conformational epitope using trypsin fragments that contain a carbohydrate recognition domain (CRD) and chimeric recombinant proteins between mMGL and a human counterpart of this molecule. Binding site for the mAb LOM-11 was mapped within the C-terminal 59 amino acids of CRD. Binding sites for all four mAbs that block carbohydrate ligand binding were also mapped in the C-terminal half of CRD. These results indicated that the calcium-dependent site potentially involved in protein-protein interaction, regulatory or for coordinated binding, is mapped within CRD in addition to the independent carbohydrate binding site, and that both of the distinct sites may have spatial proximity.
1. The present study was designed to investigate the role of nitric oxide (NO) in modulating 2,4,6-trinitrobenzene sulphonic acid (TNBS)-induced colitis in rats. 2. Damage scores and NO synthase (NOS) activity were measured. 3. The damage scores and NOS activity reached a peak on the 4th day after administration of TNBS solution (day 0), thereafter gradually decreasing, and were significantly higher than in the group treated with saline throughout the experimental period. 4. Subsequently, we divided the stage of colitis into two groups, one from day 0 to day 3 after induction of colitis, and the other from day 4 onwards. We evaluated the effects of the NOS inhibitor N(G)-monomethyl-L-arginine (L-NMMA), on TNBS-hapten-induced colitis and colonic mucosal blood flow. Two different methods of L-NMMA administration, from day 0 to day 3, and from day 4 onwards, were undertaken. 5. The damage score in the early L-NMMA treatment group was significantly higher than in the group without L-NMMA on day 14. In contrast, the damage score in the late L-NMMA treatment group was not significantly different from the group without L-NMMA. Colonic mucosal blood flow in the early L-NMMA treatment group was not significantly different from that in the late L-NMMA treatment group. 6. These data suggest that NO is important for inhibiting inflammation during the early stages.
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BACKGROUND: Tumour necrosis factor alpha (TNFalpha) has come to be regarded as a potential osteoporotic factor, because it has stimulatory effects on cells of the osteoclast lineage and has been implicated in the pathogenesis of bone loss associated with oestrogen deficiency. We recently described genetic linkage between the TNFalpha locus and human osteoporosis by sib-pair analysis. However, the molecular mechanism by which this locus regulates bone mineral density (BMD) remains unknown. AIM: We investigated whether the observed linkage reflects a sequence variation which might affect expression of the TNFalpha gene or alter the function of TNFalpha protein. SUBJECTS AND METHODS: We examined three single-nucleotide polymorphisms (SNPs) of the TNFalpha gene in a group of 390 postmenopausal Japanese women living in northern Japan. Minor-allele frequencies for the three SNPs (-1031C, -863A and -857T) in this population were 0.16, 0.13 and 0.20, respectively. RESULTS: Among the three SNPs examined, we observed a significant correlation only between the presence of a T allele at nt -1031 and decreased BMD, by analysis of variance. Among the three genotypic groups at nt -1031, mean BMD values were significantly higher in the T-negative genotype (C/C homozygotes; mean SD = 0.342 +/- 0.052 g cm(-2)), compared with T-positive genotypes (T/T homozygotes, 0.309 +/- 0.062 g cm(-2); p = 0.0253 and T/C heterozygotes, 0.305 +/- 0.062 g cm(-2); p = 0.0164). CONCLUSIONS: Given the lines of evidence from different genetic studies, we suggest that TNFalpha may play a role in pathogenesis of osteoporosis.
Introduction of two tyrosine residues into human granulocyte colony-stimulating factor (G-CSF) allowed us to obtain radioiodinated material efficiently. By using this material, specific receptors for human G-CSF were analyzed. It was found that human G-CSF receptors were expressed on several myelocytic and monocytic leukemia cell lines. Furthermore, they were also expressed on two choriocarcinoma cell lines. However, the human G-CSF receptors were not detected on other nonhematopoietic tumor cell lines examined, indicating that expression of G-CSF receptors is strictly limited as compared with receptors for granulocyte/macrophage colony-stimulating factor (GM-CSF), which are widely distributed on nonhematopoietic tumors.
OBJECTIVE: To evaluate the efficacy of etidronate (EHDP) on lumbar spine bone mineral density (LSBMD) and total bone mineral density (TBMD) in elderly women with primary hyperparathyroidism (PHPT), we compared changes in LSBMD and TBMD between patients treated by EHDP therapy and parathyroidectomy (PTX). SUBJECTS AND METHODS: Twenty-two PHPT patients were enrolled and randomized into two groups; 9 received EHDP and 13 underwent PTX. All patients were followed up for 1 year by measuring LSBMD, TBMD, serum calcium, inorganic phosphate, parathyroid hormone, 1,25-dihydroxyvitamin D, serum alkaline phosphatase, intact osteocalcin, urinary pyridinoline (U(pyd)) and urinary deoxypyridinoline (U(dpd)). The presence of spinal fractures was evaluated by X-ray photography before and after treatment. RESULTS: EHDP treatment produced a significant increase in LSBMD of 10% compared with pretreatment levels after 1 year (p < 0.03, compared to baseline), while PTX produced a significant increase in LSBMD of 20% compared to pretreatment levels (p < 0.01). However, TBMD remained unchanged for 1 year after both EHDP administration and PTX. Among biochemical bone turnover markers, EHDP administration resulted in significant decreases in alkaline phosphatase by 78%, U(pyd) by 64% and U(dpd) by 37% after 12 months compared with the pretreatment levels (p < 0.05) and intact osteocalcin by 67% after 6 months (p < 0.05). There were no differences in the fracture rate between the EHDP and PTX groups during 1 year. CONCLUSION: EHDP administration results in a somewhat lower increase in LSBMD than that following PTX and suppresses bone formation and resorption in elderly PHPT patients for 1 year. We conclude that PTX is preferable to EHDP therapy for the management of elderly PHPT patients; however, EHDP administration should also be considered for elderly patients with many complications or who are unfit for surgery.
Wild-type p53 causes cell-cycle arrest at late G1 phase and induction of apoptosis by up- regulation of waf1 and bax, respectively. Although in many cancer cells p53 is frequently mutated and loses its functions, we have proposed that mutant p53 may be involved in the anticancer mechanism of 9-hydroxy ellipticine (9HE). It was shown using flow cytometry that 9HE (10 microM) caused induction of apoptosis in G1 phase of the cell cycle in mutant p53 (p53ala143, p53his175, orp53his273) transfected Saos-2 cells, but not in p53-deficient parental Saos-2 cells. Similar induction of apoptosis was observed 24-48 h after treatment with 9HE in mutant p53-containing SW480, SK-BR-3 and MKN-1, but not in p53-deficient KATO m cells. Using G1 phase cells isolated by centrifugal elutriation, it was confirmed that 9HE caused cell cycle arrest at G1 phase and subsequently induced G1 phase-restricted apoptosis. In accordance with the induction of arrest and apoptosis in G1 phase, 9HE caused up-regulation of waf1 and bax mRNA in mutant p53-containing cells, but not in p53-deficient parental Saos-2 cells. In control experiments, adriamycin (ADR) showed neither G1-restricted apoptosis nor elevation of bax mRNA. It is suggested that 9HE may cause G1 arrest and induction of G1 phase-restricted apoptosis by restoring the wild-type function of mutant p53 protein.
A differentiation inducing factor for human monocytic leukemia cells was purified to homogeneity from conditioned medium of WI-26VA4, a human fibroblast cell line. The purification scheme consisted of micro bead silica gel chromatography, hydroxyapatite chromatography, gel filtration chromatography, chromatofocusing and reverse phase high performance liquid chromatography. The purified protein was almost homogeneous when determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and N-terminal sequence analysis. The protein has a molecular weight of approximately 27,000 and an isoelectric point of 5.4. The sequence of the first 13 N-terminal amino acid residues was consistent with that of B-cell stimulatory factor 2 (interleukin-6) except for the absence of the N-terminal proline. The purified factor induced differentiation of human monocytic leukemia U-937 cells into a monocyte/macrophage pathway.
Prostaglandin E2 (PGE2) induced differentiation of human monoblastic leukemia U-937 cells into cells with macrophage characteristics. PGE2 synergistically increased the differentiation, of U-937, ML-1 and HL-60 cells when combined with TNF. PGE1 and PGF2 also induced differentiation of U-937 cells; however, PGD2, deoxy-delta 9,12-13, 14-dihydro-PGD2 (delta 12-PGJ2), and PGI2 did not induce differentiation, either alone or in combination with TNF. PGE2 changed the dissociation constant of TNF for its receptors on U-937 cells only marginally, but it approximately doubled the number of binding sites.
Caroli's disease is a rare congenital disorder with multiple cystic dilatations of the intrahepatic bile ducts. In addition to the nonobstructive localized dilatation of the bile ducts, intraluminar bulbar protrusions of the wall and bridge formation across dilated lumina have been demonstrated on sonography and computed tomography. We present a case in which color Doppler sonography clearly showed a blood flow signal toward the periphery of the liver in the protrusion of the dilated intrahepatic bile ducts. Color Doppler sonography is a useful noninvasive method for evaluating the malformation of Caroli's disease.