Biomedical subjects

K Kashiwagi

Publications and source records attributed to K Kashiwagi.

At least 19 recordsLinked to original sources

PubMed2001

Human T lymphotropic virus type 1 infection influences hepatitis C virus clearance.

To explore the effect of human T lymphotropic virus type 1 (HTLV-1) infection on hepatitis C virus (HCV) infection, a survey for these viral infections was conducted that involved 2280 residents in an area in which HTLV-1 and HCV are endemic. The response of patients with HCV and HTLV-1 to interferon (IFN)-alpha treatment was also assessed. Antibody to HCV was detected in 13.8% of the residents tested, and antibody to HTLV-1 was detected in 15.4%. The prevalence of HCV RNA was significantly higher among residents who had antibodies to both HCV and HTLV-1 than in those who had antibodies to HCV only (P<.05). Sustained elimination of HCV RNA by IFN was significantly more frequent among patients with HCV alone than among those with HCV and HTLV-1. By logistic regression analysis, HTLV-1 infection was associated with nonresponse to IFN treatment. Thus, HTLV-1 infection affects the clearance, both natural and in association with IFN treatment, of HCV.

Adult↗

PubMed2001

Expression of thyroid hormone receptor betaA gene assayed by transgenic Xenopus laevis carrying its promoter sequences.

The responsiveness of thyroid hormone responsive element (TRE)-containing promoter sequence to thyroid hormone (TH) was studied utilizing Xenopus laevis carrying a transgene containing 5'-upstream region of TRbetaA1 gene and green fluorescent protein (EGFP) gene. EGFP-expression was seen first in neurulae, which continued to stage 45, then became weak, and again started to increase at the prometamorphic stage, culminating at the metamorphic climax stage. Immunohistochemistry identified eyes, viscera, and muscles as the EGFP-expressing larval tissues. The treatment of premetamorphic tadpoles with TH induced the precocious EGFP-expression. We also showed that the transgenic Xenopus adults were responsive to exogenous TH, a high responsiveness being seen in brain, small intestine, kidney, and bone. TRbeta-expression in the embryo, larva, and adult was verified by Western blotting. Thus, TH not only regulates the metamorphosis, but also might play some biological role(s) in embryos and adults.

Animals↗

PubMed2001

Polyamine cytotoxicity in the presence of bovine serum amine oxidase.

The toxicity of extracellular spermine, determined in the presence of fetal calf serum, was studied using three cell lines: FM3A, L1210, and NIH3T3 cells. Amine oxidase in fetal calf serum produces aminodialdehyde generating acrolein spontaneously, H(2)O(2), and ammonia from spermine. Spermine toxicity was prevented by aldehyde dehydrogenase, but not by catalase. Similar concentrations of spermine and acrolein were needed to produce toxicity. Other aldehydes (formaldehyde, acetaldehyde, and propionaldehyde) and hydrogen peroxide were less toxic than acrolein. Spermidine and 3-aminopropanal, which produces acrolein, also exhibited severe cytotoxicity. The degree of cytotoxicity of spermine, spermidine, and 3-aminopropanal was nearly parallel with the amount of acrolein produced from each compound. Thus, it was deduced that acrolein is a major toxic compound produced from polyamines (spermine and spermidine) by amine oxidase.

3T3 Cells↗

PubMed2001

Multiple polyamine transport systems on the vacuolar membrane in yeast.

We recently identified a gene (TPO1, YLL028w) that encodes a polyamine transport protein on the vacuolar membrane in yeast [Tomitori, Kashiwagi, Sakata, Kakinuma and Igarashi (1999) J. Biol. Chem. 274, 3265-3267]. Because the existence of one or more other genes for a polyamine transport protein on the vacuolar membrane was expected, we searched sequence databases for homologues of the protein encoded by TPO1. Membrane proteins encoded by the open reading frames YGR138c (TPO2), YPR156c (TPO3) and YOR273c (TPO4) were postulated to be polyamine transporters and, indeed, were subsequently shown to be polyamine transport proteins on the vacuolar membrane. Cells overexpressing these genes were resistant to polyamine toxicity and showed an increase in polyamine uptake activity and polyamine content in vacuoles. Furthermore, cells in which these genes were disrupted showed an increased sensitivity to polyamine toxicity and a decrease in polyamine uptake activity and polyamine content in vacuoles. Resistance to polyamine toxicity in cells overexpressing the genes was overcome by bafilomycin A(1), an inhibitor of the vacuolar H(+)-ATPase. Among the four polyamine transporters, those encoded by TPO2 and TPO3 were specific for spermine, whereas those encoded by TPO1 and TPO4 recognized spermidine and spermine. These results suggest that polyamine content in the cytoplasm of yeast is elaborately regulated by several polyamine transport systems in vacuoles. Furthermore, it was shown that Glu-207, Glu-324 (or Glu-323) and Glu-574 of TPO1 protein were important for the transport activity.

Amino Acid Sequence↗

PubMed2001

Polyamine enhancement of the synthesis of adenylate cyclase at the translational level and the consequential stimulation of the synthesis of the RNA polymerase sigma 28 subunit.

The effects of polyamines on the synthesis of various final sigma subunits of RNA polymerase were studied using Western blot analysis. Synthesis of final sigma(28) was stimulated 4.0-fold and that of final sigma(38) was stimulated 2.3-fold by polyamines, whereas synthesis of other final sigma subunits was not influenced by polyamines. Stimulation of final sigma(28) synthesis was due to an increase in the level of cAMP, which occurred through polyamine stimulation of the synthesis of adenylate cyclase at the level of translation. Polyamines were found to increase the translation of adenylate cyclase mRNA by facilitating the UUG codon-dependent initiation. Analysis of RNA secondary structure suggests that exposure of the Shine-Dalgarno sequence of mRNA is a prerequisite for polyamine stimulation of the UUG codon-dependent initiation.

Adenylyl Cyclases↗

PubMed2001

A sequence change (Arg158Gln) in the leucine zipper-like motif region of the MYOC/TIGR protein.

The myocilin/trabecular meshwork-inducible glucocorticoid response (MYOC/TIGR) gene was identified as a gene that caused open angle glaucoma (OAG). Single-strand conformation polymorphism analysis and subsequent sequence analysis were performed for the MYOC/TIGR gene in 120 unrelated Japanese OAG patients with increased intraocular pressure (IOP), 116 unrelated OAG patients without increased IOP, and 106 unrelated control subjects without glaucoma. An Arg158Gln sequence change in the leucine zipper-like motif (LZM) region in the myosin-homology domain was found in 2 OAG patients with or without increased IOP, and in a 56-year-old control subject without glaucoma. This is the first report of missense sequence change in the LZM region of the MYOC/TIGR protein in subjects showing various phenotypes, including a control subject. These findings suggest that Arg158Gln in the LZM region is probably a rare nondisease-causing polymorphism, despite its important role in this region, because it was found in a control subject, although Arg158Gln was previously reported as a probable disease-causing mutation.

Adult↗

PubMed2001

Analysis of myocilin gene mutations in Japanese patients with normal tension glaucoma and primary open-angle glaucoma.

The myocilin gene was identified as a gene (MYOC) that caused primary open-angle glaucoma (POAG). Although a normal tension glaucoma (NTG) patient with the myocilin gene mutation was previously reported, no study using large numbers of patients with NTG has been reported. Single-strand conformation polymorphism analysis and subsequent sequence analysis were performed for genotyping the myocilin gene in 114 unrelated Japanese patients with NTG. One hundred and nineteen patients with POAG and 100 control subjects without glaucoma were studied as reference subjects. Five amino acid sequence changes of the myocilin were identified: Arg46Stop (one NTG), Arg76Lys (four NTG, 10 POAG, seven control), Arg158Gln (one NTG, one POAG, one control) found in only Japanese, Asp208Glu (four NTG, three POAG, one control), Pro481Ser (one control). Pro481Ser was novel. Arg76Lys always occurred with 1-83 from G to A in the promoter as it was reported in Chinese. Although some Japanese patients with NTG had sequence changes of the myocilin gene, there were no apparent specific mutations in patients with NTG.

Adolescent↗

PubMed2001

Efficacy of treatment with chimeric monoclonal antibody (Infliximab) to tumor necrosis factor-alpha for Crohn's disease in Japan: evaluation by rapid turnover proteins, and radiologic and endoscopic findings.

BACKGROUND: Several studies have reported that the chimeric monoclonal antibody to tumor necrosis factor (TNF)-alpha (Infliximab) is extremely valuable in the treatment of Crohn's disease. The aim of this study was to clarify the efficacy of this treatment in Japanese patients with Crohn's disease. METHODS: A 12-week multicenter, open trial of Infliximab was carried out and involved 25 patients with moderate to severe Crohn's disease who were resistant to conventional treatment. Patients received a single 2-h intravenous infusion of Infliximab at a dose of 1, 3, 5 or 10 mg/kg bodyweight. Clinical evaluation of this treatment response was defined as a reduction in the index of the inflammatory bowel disease (IOIBD) and of the Crohn's disease activity index scores (CDAI), and in serum levels of C-reactive protein (CRP) at 2, 4, 8 and 12 weeks, and as an increase in serum levels of rapid turnover proteins as well as improvement of radiologic and endoscopic findings at 4 weeks. RESULTS: The IOIBD score was reduced after 4 weeks in 66.7% of the group receiving 1 mg/kg Infliximab, 71.4% in the group receiving 3 mg/kg, 80.0% in the group receiving 5 mg/kg, and 85.7% in the group receiving 10 mg/kg. Improvement was better maintained over 12 weeks in the 5 and 10 mg/kg groups compared with the 1 and 3 mg/kg groups. Similar results were obtained for the CDAI scores. Serum levels of rapid turnover proteins significantly increased to within the normal ranges after infusion in all groups. Seven of the 11 (63.6%) patients evaluated showed improvement of radiologic and endoscopic findings. CONCLUSIONS: A single infusion of Infliximab was effective for the treatment of Japanese patients with Crohn's disease. Serum rapid turnover proteins reflected the clinical response to antibody for TNF-alpha well.

Adult↗

PubMed2001

Matrix metalloproteinases in human diabetic and nondiabetic vitreous.

PURPOSE: To compare matrix metalloproteinase (MMP) activities in human vitreous samples from patients with diabetic retinopathy (DR) and other vitreoretinal diseases, and to investigate the factors influencing the MMP activities in human DR vitreous samples. METHODS: Thirty-one diabetic and 17 nondiabetic vitreous samples (from nine patients with macular holes and eight patients with epiretinal membranes) were examined. Samples collected at the time of pars plana vitrectomy were subjected to substrate zymography to conduct a quantitative analysis of MMP activity. Immunoblotting against antihuman MMP-1, 2, and 9 was performed to identify MMP in vitreous samples. The effects of posterior vitreous detachment (PVD), vitreous hemorrhage, proliferative membrane, traction detachment, and cystoid macular edema on MMP activities were investigated. RESULTS: All vitreous samples from both DR and non-DR patients showed a single band at the position of 72 kD, corresponding to MMP-2. Another band at 99 kD, corresponding to MMP-9, was detected significantly more often in DR samples than in non-DR samples: 45.2% and 0%, respectively (P = 0.0007). The number of samples showing a band from MMP-9 was significantly higher in partial PVD samples than in complete PVD samples: 66.7% and 15.4%, respectively (P = 0.001). CONCLUSION: The results indicated that MMP-9 may be involved in DR and that partial PVD may be related to the MMP-9 activity in DR.

Adult↗

PubMed2001

Cystoid macular edema associated with topical latanoprost in glaucomatous eyes with a normally functioning blood-ocular barrier.

PURPOSE: To study prospectively using optical coherence tomography (OCT) whether topical latanoprost induces retinal disorders, such as cystoid macular edema, in patients with glaucoma and a normally functioning blood-ocular barrier. METHODS: Sixty-eight eyes of 38 patients with glaucoma and no history of intraocular surgery, uveitis, or laser trabeculoplasty were studied. Before initiation of latanoprost treatment and after 1, 3, and 6 months of treatment, OCT images were taken, and the following tests were performed: visual acuity examination, fundus ophthalmoscopy, intraocular pressure measurement, and fundus color photography. To evaluate retinal thickness in the fovea accurately. OCT scanning was repeated six times, and the smallest value was used as the retinal thickness in the fovea. RESULTS: Latanoprost ophthalmic solution did not influence retinal thickness in the fovea at any investigated time points compared with the time before instillation, and no changes were observed in visual acuity, ophthalmoscopic findings, and fundus photographs. The intraocular pressure was reduced significantly at all investigated time points compared with the time before instillation. CONCLUSIONS: It is unlikely that topical latanoprost induces retinal disorders, such as cystoid macular edema, in glaucomatous eyes with a normally functioning blood-ocular barrier.

Adult↗

PubMed2001

Isopropyl unoprostone increases the activities of matrix metalloproteinases in cultured monkey ciliary muscle cells.

PURPOSE: The mechanism by which the prostaglandin F2alpha-related antiglaucoma compound isopropyl unoprostone (referred to as unoprostone) reduces intraocular pressure is largely unknown. Another prostaglandin F2alpha-related compound, latanoprost, influences the activities of matrix metalloproteinases in ciliary muscle. Unoprostone ophthalmic solution is metabolized to oxidized metabolites, mainly M1 and M2, in the eye. The aim of this study was to investigate whether intraocular metabolites of unoprostone, M1 and M2, change the metalloproteinase activity in cultured monkey ciliary muscle cells. MATERIALS AND METHODS: Monkey ciliary muscle cells and trabecular meshwork cells were grown separately to confluence in monolayer cell cultures. M1 (10 nM, 100 nM, or 1 microM), M2 (10 nM, 100 nM, or 1 microM), 100 nM prostaglandin F2alpha, or vehicle solutions were added to each culture medium for 48 hours. The media were then assayed to measure metalloproteinase activities quantitatively by means of substrate zymography. RESULTS: Compared with the vehicle controls, M1, M2, and prostaglandin F2alpha significantly increased the metalloproteinase-2 activity in cultured ciliary muscle cells in a dose-dependent manner, but did not affect the metalloproteinase-2 activity in cultured trabecular meshwork cells. All experimented prostaglandins slightly increased metalloproteinase-9 activity in ciliary muscle cells, although these changes were not significant. CONCLUSIONS: The current results show that unoprostone influences the metabolism of the extracellular matrix in the ciliary muscle and that remodeling of the extracellular matrix in the ciliary muscle may be a possible mechanism by which unoprostone ophthalmic solution reduces intraocular pressure.

Animals↗

PubMed2001

Iridial pigmentation induced by latanoprost ophthalmic solution in Japanese glaucoma patients.

PURPOSE: To investigate the incidence of iridial pigmentation induced by latanoprost ophthalmic solution in Japanese glaucoma patients by a prospective and observer-masked study. PATIENTS AND METHODS: Sixty-nine eyes of 69 glaucoma patients were included. Patients who had undergone intraocular surgery, laser trabeculoplasty, and laser iridotomy within 12 months before enrollment, and patients with history of uveitis and any changes in antiglaucoma drugs within 6 months before enrollment were excluded. Iridial photographs were taken by one examiner under the same conditions at 1, 3, and 6 months after the initiation of latanoprost treatment. Three glaucoma specialists, masked of patient information, independently assessed the iridial pigmentation. Cases with iridial pigmentation diagnosed by three specialists were categorized as showing a definite increase in iridial pigmentation. RESULTS: A definite increase in iridial pigmentation occurred in 3.5%, 9.7%, and 35.0% of eyes within 1, 3, and 6 months of treatment, respectively. Age, gender, or concomitantly used eyedrops did not significantly influence the incidence of iridial pigmentation within 6 months of instillation. A reduction of intraocular pressure by latanoprost did not differ significantly between patients with and without iridial pigmentation. CONCLUSION: The incidence of iridial pigmentation by latanoprost ophthalmic solution in Japanese patients was higher than previously reported values in pigmented races.

Adult↗

PubMed2001

Properties of a revertant of Escherichia coli viable in the presence of spermidine accumulation: increase in L-glycerol 3-phosphate.

Escherichia coli CAG2242 cells are deficient in the speG gene encoding spermidine acetyltransferase. When these cells were cultured in the presence of 0.5 to 4 mM spermidine, their viability was greatly decreased through the inhibition of protein synthesis by overaccumulation of spermidine. When the cells were cultured with a high concentration of spermidine (4 mM), a revertant strain was obtained. We found that a 55-kDa protein, glycerol kinase, was overexpressed in the revertant and that synthesis of a ribosome modulation factor and the RNA polymerase sigma(38) subunit, factors important for cell viability, was increased in the revertant. Levels of L-glycerol 3-phosphate also increased in the revertant. Transformation of glpFK, which encodes a glycerol diffusion facilitator (glpF) and glycerol kinase (glpK), to E. coli CAG2242 partially prevented the cell death caused by accumulation of spermidine. It was also found that L-glycerol 3-phosphate inhibited spermidine binding to ribosomes and attenuated the inhibition of protein synthesis caused by high concentrations of spermidine. These results indicate that L-glycerol 3-phosphate reduces the binding of excess amounts of spermidine to ribosomes so that protein synthesis is recovered.

Amino Acid Sequence↗

PubMed2001

Polymyositis, pulmonary fibrosis and malignant lymphoma associated with hepatitis C virus infection.

Polymyositis has been associated with various viral infections, and a spectrum of immune-related diseases may occur with hepatitis C (HCV) infection. Both polymyositis and HCV infection may be accompanied by pulmonary fibrosis. An association between polymyositis and malignancy has also been reported. We report a 55-year-old woman accompanied cryoglobulinemia with HCV infection and manifesting polymyositis, pulmonary fibrosis and malignant lymphoma. Steroid therapy was effective to improve interstitial pneumonia, polymyositis, and liver function.

Cryoglobulinemia↗

PubMed2001

Effects of retinal glial cells on isolated rat retinal ganglion cells.

PURPOSE: The effect of retinal glial cells on retinal ganglion cell (RGC) survival was investigated in cocultures of pure, isolated retinal glial cells with pure, isolated RGCs. METHODS: RGCs from 2-day-old rats were cocultured for 48 hours, avoiding direct contact between cell types, with either nonconfluent retinal glial cells from 3-day-old rats or confluent retinal glial cells from 3-day-old, 12-day-old, or 1-year-old rats. Survival of RGCs was evaluated by flow cytometry. Amino acids were determined in culture medium. The effects of glutamate antagonists, 6-cyano-7-nitroquinoxaline-2,3-dione and MK801, a nitric oxide (NO) scavenger, 2-(4-carboxyphenyl)-4,4,5,5tetramethylimidazoline-1-oxyl-3-oxide potassium salt (c-PTIO), and an NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME), were examined. RESULTS: Nonconfluent retinal glial cells significantly reduced the survival of small and large RGCs, but confluent retinal glial cells reduced the survival of only small RGCs, regardless of the rat's age at the time of retinal glial cell harvesting. Profiles of some amino acids significantly varied, depending on the culture condition. Cocultures of RGCs with nonconfluent retinal glial cells released significantly more glutamate into the medium than cocultures of RGCs with confluent retinal glial cells or RGCs in pure culture. The glutamate antagonists improved the survival of RGCs cocultured with nonconfluent retinal glial cells, especially when the two were administered in combination, and in the case of large RGCs. c-PTIO and L-NAME, also improved the survival of RGCs cocultured with nonconfluent retinal glial cells. CONCLUSIONS: Adverse effects of retinal glial cells on the survival of RGCs varied by size of the RGCs and retinal glial cell confluence. Glutamate and NO may be involved in retinal glial cell-related antisurvival effects.

Animals↗

PubMed2000

Identification of the putrescine recognition site on polyamine transport protein PotE.

The PotE protein can catalyze both uptake and excretion of putrescine. The K(m) values of putrescine for uptake and excretion are 1.8 and 73 microm, respectively. Uptake of putrescine is dependent on the membrane potential, whereas excretion involves putrescine-ornithine antiporter activity. Amino acids involved in both activities were identified using mutated PotE proteins. It was found that Cys(62), Trp(201), Trp(292), and Tyr(425) were strongly involved in both activities, and that Tyr(92), Cys(210), Cys(285), and Cys(286) were moderately involved in the activities. Mutations of Tyr(78), Trp(90), and Trp(422) mainly affected uptake activity, and the K(m) values for putrescine uptake by these PotE mutants increased greatly, indicating that these amino acids are involved in the high affinity uptake of putrescine by PotE. Mutations of Lys(301) and Tyr(308) mainly affected excretion activity (putrescine-ornithine antiporter activity), and excretion by these mutants was not stimulated by ornithine, indicating that these amino acids are involved in the recognition of ornithine. It was found that the putrescine and ornithine recognition site on PotE is located at the cytoplasmic surface and the vestibule of the pore consisting of 12 transmembrane segments. Based on the results of competition experiments with various putrescine analogues and the disulfide cross-linking of PotE between cytoplasmic loops and the COOH terminus, a model of the putrescine recognition site on PotE consisting of the identified amino acids is presented.

Amino Acid Sequence↗

PubMed2000

Antioxidative galloyl esters as enzyme inhibitors of p-hydroxybenzoate hydroxylase.

Gallic acid and its esters were evaluated as enzyme inhibitors of recombinant p-hydroxybenzoate hydroxylase (PHBH), a NADPH-dependent flavin monooxygenase from Pseudomonas aeruginosa. n-Dodecyl gallate (DG) (IC(50)=16 microM) and (-)-epigallocatechin-3-O-gallate (EGCG) (IC(50)=16 microM), a major component of green tea polyphenols, showed the most potent inhibition, while product-like gallic acid did not inhibit the enzyme significantly (IC(50)>250 microM). Inhibition kinetics revealed that both DG and EGCG inhibited PHBH in a non-competitive manner (K(I)=18.1 and 14.0 microM, respectively). The enzyme inhibition was caused by specific binding of the antioxidative gallate to the enzyme, and by scavenging reactive oxygen species required for the monooxygenase reaction. Molecular modeling predicted that EGCG binds to the enzyme in the proximity of the FAD binding site via formation of three hydrogen bonds.

4-Hydroxybenzoate-3-Monooxygenase↗

PubMed2000

Increase in cap- and IRES-dependent protein synthesis by overproduction of translation initiation factor eIF4G.

The role of eIF4G during the initiation of protein synthesis was studied using mouse mammary carcinoma FM3A cells and FM4G cells that overproduce an N-terminally truncated form of eIF4G, which lacks the binding site of poly(A)-binding protein. An increase in eIF4G was correlated with an increase in protein synthesis and RNA helicase activity. Translation of mRNAshaving both short and long 5'-untranslated regions (5'-UTR) increased significantly in FM4G cells compared to that in FM3A cells. Both full-length and N-terminally truncated eIF4G transfectants of NIH3T3 cells formed colonies in soft agar and increased the saturation density of cell growth, indicating that both eIF4Gs function similarly. We also found that an internal ribosome entry site (IRES) exists in the 5'-UTR of ornithinedecarboxylase mRNA and that IRES-dependent protein synthesis increased in FM4G cells. Our results indicate that an increase in eIF4G contributes to the formation of active eIF4F similarly to that caused by an increase in eIF4E, as well as to a stimulation of IRES-dependent protein synthesis.

3T3 Cells↗