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K Arima

Publications and source records attributed to K Arima.

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

Amino acid sequence and some properties of phytolacain G, a cysteine protease from growing fruit of pokeweed, Phytolacca americana.

A protease, phytolacain G, has been found to appear on CM-Sepharose ion-exchange chromatography of greenish small-size fruits of pokeweed, Phytolacca americana L, from ca. 2 weeks after flowering, and increases during fruit enlargement. Reddish ripe fruit of the pokeweed contained both phytolacain G and R. The molecular mass of phytolacain G was estimated to be 25.5 kDa by SDS-PAGE. Its amino acid sequence was reconstructed by automated sequence analysis of the peptides obtained after cleavage with Achromobacter protease I, chymotrypsin, and cyanogen bromide. The enzyme is composed of 216 amino acid residues, of which it shares 152 identical amino acid residues (70%) with phytolacain R, 126 (58%) with melain G, 108 (50%) with papain, 106 (49%) with actinidain, and 96 (44%) with stem bromelain. The amino acid residues forming the substrate binding S(2) pocket of papain, Tyr67, Pro68, Trp69, Val133, and Phe207, were predicted to be replaced by Trp, Met, His, Ala, and Ser in phytolacain G, respectively. As a consequence of these substitutions, the S(2) pocket is expected to be less hydrophobic in phytolacain G than in papain.

Amino Acid Sequence↗
PubMed2000

Two brothers with frontotemporal dementia and parkinsonism with an N279K mutation of the tau gene.

OBJECTIVE: To characterize the clinical diagnostic features, neuropathologic phenotype of tau deposition, and subunit structure of tau filaments in patients who had an asparagine-to-lysine substitution at codon 279 (the N279K missense mutation) of the gene for microtubule-associated tau protein. BACKGROUND: The N279K mutation is a causative genetic defect for pallidopontonigral degeneration in an American kindred that presents with frontotemporal dementia (FTD) and parkinsonism. METHODS: The authors analyzed retrospectively the clinical symptoms of two Japanese brothers who carry this mutation. Postmortem neuropathologic and electron microscopic studies, and Western blot analysis of insoluble tau were performed to correlate tau-mediated lesions with neurologic deficits. RESULTS: Both patients exhibited impairment in recent memory, parkinsonism, and corticospinal disturbances in addition to FTD. Parkinsonism in one patient was responsive temporarily to l-dopa. There was intense tau deposition in the medial temporal cortices and upper and lower motor neurons with accompanying corticospinal tract degeneration. Two distinct tau isoforms with four microtubule-binding repeats, in hyperphosphorylated forms, were the primary constituents of insoluble tau, which aggregated to the filamentous component, termed "paired tubules," in neurons, oligodendrocytes, and astrocytes. The elemental filaments were hollow tubules measuring 11 to 12 nm in diameter, two of which adhered to each other along their longitudinal axes to form "paired tubules." CONCLUSIONS: Early memory loss and pyramidal signs, which are atypical of FTD, can be presenting symptoms in this disorder. The authors demonstrated that the subunit structure of tau filaments is a pair of hollow tubules despite the prevailing twisted ribbon model.

Amino Acid Substitution↗
PubMed2000

Genetic variants of IL-13 signalling and human asthma and atopy.

Asthma and atopy show epidemiological association and are biologically linked by T-helper type 2 (T(h)2) cytokine-driven inflammatory mechanisms. IL-4 operates through the IL-4 receptor (IL-4R, a heterodimer of IL-4Ralpha and either gammac or IL-13Ralpha1) and IL-13 operates through IL-13R (a heterodimer of IL-4Ralpha and IL-13Ralpha1) to promote IgE synthesis and IgE-based mucosal inflammation which typify atopy. Recent animal model data suggest that IL-13 is a central cytokine in promoting asthma, through the stimulation of bronchial epithelial mucus secretion and smooth muscle hyper-reactivity. We investigated the role of common genetic variants of IL-13 and IL-13Ralpha1 in human asthma, considering IgE levels. A novel variant of human IL-13, Gln110Arg, on chromosome 5q31, associated with asthma rather than IgE levels in case-control populations from Britain and Japan [peak odds ratio (OR) = 2.31, 95% CI 1.33-4.00]; the variant also predicted asthma and higher serum IL-13 levels in a general, Japanese paediatric population. Immunohistochemistry demonstrated that both subunits of IL-13R are prominently expressed in bronchial epithelium and smooth muscle from asthmatic subjects. Detailed molecular modelling analyses indicate that residue 110 of IL-13, the site of the charge-modifying variants Arg and Gln, is important in the internal constitution of the ligand and crucial in ligand-receptor interaction. A non-coding variant of IL-13Ralpha1, A1398G, on chromosome Xq13, associated primarily with high IgE levels (OR = 3. 38 in males, 1.10 in females) rather than asthma. Thus, certain variants of IL-13 signalling are likely to be important promoters of human asthma; detailed functional analysis of their actions is needed.

Adult↗
PubMed2000

The developmental and aging changes of Down's syndrome cell adhesion molecule expression in normal and Down's syndrome brains.

We studied the expression of Down's syndrome cell adhesion molecule (DSCAM) in Down's syndrome (DS) and control brains, using antisera against peptide fragments of DSCAM. On Western blots of human, mouse and rat brain homogenates, the antisera recognized a product at approximately 200 kDa. In the brain of a 2-year-old patient with DS, Western blotting revealed an overexpression of DSCAM compared to an age-matched control. Immunohistochemistry demonstrated DSCAM in the cerebral and cerebellar white matter of both control and DS subjects, in accordance with the temporal and spatial sequence of myelination. In DS brains, immunoreactivity for DSCAM, compared to that for controls, was enhanced in the Purkinje cells at all ages, and in the cortical neurons during adulthood. In demented DS patients, DSCAM immunoreactivity was observed in the core and periphery of senile plaques. The pattern of DSCAM expression suggests that it may play a role as an adhesion molecule regulating myelination. The overexpression of DSCAM may also play a role in the mental retardation and the precocious dementia of DS patients, although the mechanism of neuronal dysfunction is undetermined.

Adolescent↗
PubMed2000

NACP/alpha-synuclein and tau constitute two distinctive subsets of filaments in the same neuronal inclusions in brains from a family of parkinsonism and dementia with Lewy bodies: double-immunolabeling fluorescence and electron microscopic studies.

The co-localization of NACP/alpha-synuclein and tau epitopes was examined in the brain stem and hippocampal formation in two patients from a family of autosomal dominant parkinsonism and dementia with Lewy bodies (LBs) without two reported missense mutations in the NACP gene. Double-labeling immunofluorescence study revealed that some brain stem LBs, cortical LBs, pale bodies, Lewy-related neurites, and neurofibrillary tangles expressed both NACP epitopes and the PHF tau AT8 epitope. Double-immunolabeling electron microscopy demonstrated that the NACP antibody selectively labeled 9- to 13-nm-thick straight filaments (LB filaments), whereas AT8 recognized twisted tubules with 80-to 100-nm-interval constrictions in the same neuronal inclusions. We show that NACP and tau aggregate into different filamentous components even if both proteins are incorporated into the same inclusions.

Adult↗
PubMed2000

Physiological expression of the gene for PrP-like protein, PrPLP/Dpl, by brain endothelial cells and its ectopic expression in neurons of PrP-deficient mice ataxic due to Purkinje cell degeneration.

Recently, a novel gene encoding a prion protein (PrP)-like glycoprotein, PrPLP/Dpl, was identified as being expressed ectopically by neurons of the ataxic PrP-deficient (PRNP(-/-)) mouse lines exhibiting Purkinje cell degeneration. In adult wild-type mice, PrPLP/Dpl mRNA was physiologically expressed at a high level by testis and heart, but was barely detectable in brain. However, transient expression of PrPLP/Dpl mRNA was detectable by Northern blotting in the brain of neonatal wild-type mice, showing maximal expression around 1 week after birth. In situ hybridization paired with immunohistochemistry using anti-factor VIII serum identified brain endothelial cells as expressing the transcripts. Moreover, in the neonatal wild-type mice, the PrPLP/Dpl mRNA colocalized with factor VIII immunoreactivities in spleen and was detectable on capillaries in lamina propria mucosa of gut. These findings suggested a role of PrPLP/Dpl in angiogenesis, in particular blood-brain barrier maturation in the central nervous system. Even in the ataxic Ngsk PRNP(-/-) mice, the physiological regulation of PrPLP/Dpl mRNA expression in brain endothelial cells was still preserved. This strongly supports the argument that the ectopic expression of PrPLP/Dpl in neurons, but not deregulation of its physiological expression in endothelial cells, is involved in the neuronal degeneration in ataxic PRNP(-/-) mice.

Adenosine Triphosphatases↗
PubMed2000

Isolation and characterization of a serine protease from the sprouts of Pleioblastus hindsii Nakai.

An endopeptidase has been purified from sprouts of bamboo (Pleioblastus hindsii Nakai) to electrophoretic homogeneity by four purification steps. Its Mr was estimated to be 82 kDa by SDS-PAGE. Enzyme activity was inhibited strongly by diisopropyl fluorophosphate, and weakly by p-chloromercuriphenylsulfonic acid, but not at all by EDTA or pepstatin, indicating that it was a serine protease. The preferential cleavage sites for this protease were found to be large hydrophobic and amide residues at the P1 position. The specificity of the bamboo serine protease differed from that of cucumisin [EC 3.4.21.25], which cleaved the charged amino acid residues at the P1 position.

Amino Acid Sequence↗
PubMed2000

Cleavage specificity of cucumisin, a serine protease, with synthetic substrates.

The substrate specificity of a plant serine protease, cucumisin (EC 3.4.21.25), was studied by the use of synthetic oligopeptides and peptidyl-pNA substrates. Since P1'-Ser, Ala, and Gly substrates were hydrolyzed rapidly, cucumisin appears to prefer a small side chain at the P1' position of the oligopeptide substrate. The k(cat)/Km for the hydrolysis of P1-Leu, Ala, Phe, and Glu substrates demonstrated that they were preferentially cleaved over P1-Lys, diaminopropionic acid (Dap), Gly, Val, and Pro substrates. From the digestion of peptidyl-pNAs, the specificity of the protease was determined to be broad, but the preferential cleavage sites were hydrophobic amino acid residues at the P1 position.

Cucurbitaceae↗
PubMed2000

Cucumisin-like protease from the latex of Euphorbia supina.

A protease has been purified from the latex of Euphorbia supina Rafin by two steps of chromatography. The Mr was estimated by SDS-PAGE to be 80 kDa. Its activity was inhibited strongly by diisopropyl fluorophosphate, but not by EDTA, pepstatin, or cysteine protease inhibitors, indicating that the enzyme is a serine protease. The specificity of the protease is broad, but the preferential cleavage sites were C-terminal sites of hydrophobic amino acid residues. The N-terminal sequence of the first fifteen residues was determined and six of the residues match those in cucumisin [EC 3.4.21.25], a protease from the sarcocarp of melon fruit (Cucumis melo L. var. Prince). The results indicate that the E. supina protease is a cucumisin-like serine protease.

Amino Acid Sequence↗
PubMed2000

Cardiopulmonary cerebral resuscitation using emergency cardiopulmonary bypass, coronary reperfusion therapy and mild hypothermia in patients with cardiac arrest outside the hospital.

OBJECTIVES: The purpose of this study was to evaluate the efficacy of an alternative cardiopulmonary cerebral resuscitation (CPCR) using emergency cardiopulmonary bypass (CPB), coronary reperfusion therapy and mild hypothermia. BACKGROUND: Good recovery of patients with out-of-hospital cardiac arrest is still inadequate. An alternative therapeutic method for patients who do not respond to conventional CPCR is required. METHODS: A prospective preliminary study was performed in 50 patients with out-of-hospital cardiac arrest meeting the inclusion criteria. Patients were treated with standard CPCR and, if there was no response, by emergency CPB plus intra-aortic balloon pumping. Immediate coronary angiography for coronary reperfusion therapy was performed in patients with suspected acute coronary syndrome. Subsequently, in patients with systolic blood pressure above 90 mm Hg and Glasgow coma scale score of 3 to 5, mild hypothermia (34 C for at least two days) was induced by coil cooling. Neurologic outcome was assessed by cerebral performance categories at hospital discharge. RESULTS: Thirty-six of the 50 patients were treated with emergency CPB, and 30 of 39 patients who underwent angiography suffered acute coronary artery occlusion. Return of spontaneous circulation and successful coronary reperfusion were achieved in 92% and 87%, respectively. Mild hypothermia could be induced in 23 patients, and 12 (52%) of them showed good recovery. Factors related to a good recovery were cardiac index in hypothermia and the presence of serious complications with hypothermia or CPB. CONCLUSIONS: The alternative CPCR demonstrated an improvement in the incidence of good recovery. Based upon these findings, randomized studies of this hypothermia are needed.

Adolescent↗
PubMed2000

Early appearance but lagged accumulation of detergent-insoluble prion protein in the brains of mice inoculated with a mouse-adapted Creutzfeldt-Jakob disease agent.

1. To elucidate mechanisms for the generation of the detergent-insoluble, proteinase K-resistant prion protein (PrP(Sc)) from the detergent-soluble, proteinase K-sensitive PrP (PrP(C)) and the replication of the infectious agent in prion diseases, we followed the kinetics of detergent-insoluble PrP and PrP(Sc) levels, infectious titers, and associated pathological changes in the brains of mice inoculated with a mouse-adapted Creutzfeldt Jakob disease agent. 2. PrP(Sc) in brain homogenate and detergent-insoluble PrP enriched by two-cycle ultracentrifugation were detected by immunoblotting and their relative amounts were estimated according to a standard curve plotted between the amount of PrP and signal intensity on immunoblotting. The titer of infectivity was determined by the incubation periods of mice inoculated with the unfractionated homogenate on the basis of a standard curve plotted between the titer and incubation period. 3. Detergent-insoluble PrP became detectable 4 weeks postinoculation (p.i.) well before the detection of PrP(Sc). The low level of detergent-insoluble PrP continued until dramatic accumulation occurred at 14 weeks p.i., correlating well with the accumulation of PrP(Sc) and development of pathological changes. The infectious titer was undetectable at 4 weeks p.i. and its logarithmic increase occurred 10 weeks p.i. preceding the logarithmic accumulation of PrPs. 4. The lag time of detergent-insoluble PrP accumulation and the discrepancy between infectious titers and PrPs observed during the early period after inoculation suggest a slow and rate-limiting step for the detergent-insoluble PrP to become the infectious agent-associated PrP(Sc).

Animals↗
PubMed2000

Identification of a novel gene encoding a PrP-like protein expressed as chimeric transcripts fused to PrP exon 1/2 in ataxic mouse line with a disrupted PrP gene.

1. Mouse lines lacking prion protein (PrP(C)) have a puzzling phenotypic discrepancy. Some, but not all, developed late-onset ataxia due to Purkinje cell degeneration. 2. Here, we identified aberrant mRNA species in the brain of Ngsk Prnp0/0 ataxic, but not in nonataxic Zrch Prnp0/0 mouse line. These mRNAs were chimeric between the noncoding exons 1 and 2 of the PrP gene (Prnp) and the novel sequence encoding PrP-like protein (PrPLP), a putative membrane glycoprotein with 23% identity to PrP(C) in the primary amino acid structure. The chimeric mRNAs were generated from the disrupted Prnp locus of Ngsk Prnp0/0 mice lacking a part of the Prnp intron 2 and its splice acceptor signal. 3. In the brain of wild-type and Zrch Prnp0/0 mice, PrPLP mRNA was barely detectable. In contrast, in the brain of Ngsk Prnp0/0 mice, PrP/PrPLP chimeric mRNAs were expressed in neurons, at a particularly high level in hippocampus pyramidal cells and Purkinje cells under the control of the Prnp promoter. 4. In addition to the functional loss of PrP(C), ectopic PrPLP expression from the chimeric mRNAs could also be involved in the Purkinje cell degeneration in Ngsk Prnp0/0 mice.

Amino Acid Sequence↗
PubMed2000

The usefulness of power Doppler ultrasonography for diagnosing prostate cancer: histological correlation of each biopsy site.

OBJECTIVE: To correlate the findings of power Doppler ultrasonography (PDUS) of the prostate with those of site-specific transrectal ultrasonography (TRUS)-guided biopsy. PATIENTS AND METHODS: The study comprised 28 patients referred to our institution for TRUS-guided prostate biopsy because of an elevated PSA level and/or abnormal digital rectal examination. PDUS findings were graded 0, 1 or 2; grades 0-1 were considered as negative and grade 2 as positive. The blood volume of each biopsy site was also determined using the mean number (MN) value that represents the average vascularity in a 5-mm square sample. PDUS values were correlated with the histological findings of 147 biopsies with 19 focal lesions. RESULTS: Grade 2 was assigned to 19 sites, grade 1 to 52 sites, and grade 0 to 76 sites. Fourteen of the 19 PDUS findings of grade 2 sites revealed carcinoma and five were grade 1. Ten of 35 TRUS-positive sites were carcinomas, three benign prostatic hyperplasia (BPH) and 22 normal. The MN value for prostatic carcinoma was 4.33, for BPH 11.7 and for normal tissue 4.7. The overall sensitivity of PDUS was 74%, the specificity 96% and the positive predictive value 74%. CONCLUSIONS: Because TRUS alone cannot detect all cancers, PDUS should be used routinely in all patients undergoing TRUS-guided biopsy, to improve the diagnostic yield of prostate cancer.

Aged↗
PubMed2000

Production of interleukin (IL)-6 and IL-8 by a choriocarcinoma cell line, BeWo.

To clarify the biological and pathological features of choriocarcinoma, we evaluated the in vitro production of cytokines by a choriocarcinoma cell line, BeWo. We measured the concentration of interleukin (IL)-6 and IL-8 in the culture media of BeWo cells after stimulation with various modulatory agents of cytokine expression by enzyme-linked immunosorbent assays. Northern blot analysis was used to examine the expression of IL-6 and IL-8 mRNA in these cells. A weak expression of IL-6 and IL-8 was detected in unstimulated BeWo cells by both methods. IL-6 transcription and secretion were dose-dependently enhanced by stimulation with IL-1beta, tumour necrosis factor (TNF)-alpha, transforming growth factor (TGF)-beta1 and 12-O-tetradecanoyl phorbol-13-acetate (TPA). Forskolin, lipopolysaccharide and interferon-gamma had no effect on these cytokines production. The TNF-alpha-induced secretion of IL-6 was inhibited by dexamethasone. The TPA-induced production of IL-6 was inhibited by 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine and sphyngosine, suggesting the involvement of a protein kinase C-dependent pathway. Levels of IL-8 mRNA and protein were also dose-dependently increased by stimulation with IL-1beta, TNF-alpha and TPA. In contrast to IL-6, the expression of IL-8 was not affected by TGF-beta1. It is suggested that, in addition to the production of steroidal and non-steroidal hormones, these cytokines may serve as part of a cytokine network that modulates the proliferation and angiogenesis of choriocarcinomas.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2000

Characterization of IL-4 and IL-13 signals dependent on the human IL-13 receptor alpha chain 1: redundancy of requirement of tyrosine residue for STAT3 activation.

IL-4 and IL-13 are pleiotropic cytokines whose biological activities overlap with each other. IL-13 receptor alpha chain 1 (IL-13R alpha 1) is necessary for binding to IL-13, and the heterodimer composed of IL-13R alpha 1 and IL-4R alpha chain transduces IL-13 and IL-4 signals; however, the functional mapping of the intracellular domain of IL-13R alpha 1 is not fully understood. In this study, we constructed wild and mutated types of human IL-13R alpha 1, and analyzed IL-4 and IL-13 signals using an IL-13R alpha 1-transfected human B cell line. Expression of IL-13R alpha 1 evoked STAT3 activation by IL-4 and IL-13, and in stimulated human B cells, on which IL-13R alpha 1 was highly expressed, IL-4 and IL-13 induced STAT3 activation. Replacement of the two tyrosine residues completely abolished STAT3 activation, although replacing either tyrosine residue alone retained it. Furthermore, we found that the Box1 region and the C-terminal tail of IL-13R alpha 1 were critical for binding to Tyk2, and activation of Jak1, Tyk2, the insulin receptor substrate-1 and STAT6 respectively. These results suggest that STAT3 activation is involved with IL-4 and IL-13 signals in human B cells along with the activation of STAT6, and that there is a unique sequence in IL-13R alpha 1 to activate STAT3.

Animals↗
PubMed2000

Expression of the p53 tumor suppressor gene is up-regulated by depletion of intracellular zinc in HepG2 cells.

Expression and activation of the p53 tumor suppressor protein are modulated by various cellular stimuli. The objective of this work was to examine the influence of zinc depletion on the expression of p53 in HepG2 cells. Two different low Zn (ZD) media, Zn-free Opti-MEM and a ZD medium containing Chelex-100 treated serum, were used to deplete cellular zinc over one passage. Cellular zinc levels of ZD cells were significantly lower than in their controls in both the Opti-MEM and Chelex studies. p53 mRNA abundance was 187% higher in ZD Opti-MEM cells and >100% higher in ZD Chelex cells compared with their respective controls. To examine whether the effects were specific to zinc depletion, a third, zinc-replenished group (ZDA) was included in the Opti-MEM study in which cells were cultured in ZD media for nearly one passage before a change was made to zinc-adequate (ZA) medium for the last 24 h. Zinc levels in the ZDA cells were significantly higher than in ZD cells, and p53 mRNA abundance was normalized to control levels. Nuclear p53 protein levels were >100% higher in the ZD Opti-MEM cells than in ZA cells. Interestingly, the ZDA Opti-MEM cells had significantly lower levels of nuclear p53 protein than both the ZA and ZD cells. These data suggest that expression of p53, a critical component in the maintenance of genomic stability, may be affected by reductions in cellular zinc.

Carcinoma, Hepatocellular↗
PubMed2000

Effects of lipopolysaccharide and cytokines on production of RANTES by cultured human endometrial stromal cells.

RANTES (regulated upon activation, normal T cell expressed and secreted), which is a potent chemoattractant for eosinophils, lymphocytes, and monocytes, was recently detected in the human endometrium. The effects of modulators of endometrial function, including lipopolysaccharide (LPS), tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-4 and interferon-gamma (IFN-gamma), on the production of RANTES by endometrial stromal cells (ESC) were examined by an enzyme-linked immunosorbent assay and Northern blot analysis. The concentration of RANTES in the culture media of non-stimulated ESC was below the level of detection. The concentration of RANTES was increased by the addition of TNF-alpha, IL-1beta and LPS. IFN-gamma synergistically enhanced the TNF-alpha- and LPS-induced RANTES expression, but had no effect on the IL-1beta-induced RANTES expression. The TNF-alpha-induced production of RANTES by ESC was inhibited by IL-4. The transcription of RANTES in ESC was also stimulated by TNF-alpha, IL-1beta and LPS in a dose-dependent manner. It is suggested that the LPS and cytokines secreted by the maternal decidual tissue and the developing embryo may regulate the production of RANTES by ESC. The modulation of RANTES concentration in the local environment may contribute to the pathophysiological processes of human reproduction by regulating the immunological reaction at the fetal-maternal interface.

Adult↗