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Biomedical subjects

Y Yamada

Publications and source records attributed to Y Yamada.

At least 127 records · Page 7Linked to original sources
PubMed2001

Short arm region of laminin-5 gamma2 chain: structure, mechanism of processing and binding to heparin and proteins.

Laminin-5 is a typical component of several epithelial tissues and contains a unique gamma2 chain which can be proteolytically processed by BMP-1. This occurs in the N-terminal half of the gamma2 chain (606 residues), which consists of two rod-like tandem arrays of LE modules, LE1-3 and LE4-6, that flank a globular L4m module containing the cleavage site. Recombinant analysis of L4m, which includes an additional imperfect LE module essential for proper folding, demonstrated an unusual pattern of disulfide bonding. These connectivities prevented the release of gamma2LE1-3L4 m after BMP-1 cleavage which required in addition disulfide reshuffling by isomerases. The liberated segment bound through its L4 m module to heparin, nidogen-1, fibulin-1 and fibulin-2. A further heparin/sulfatide-binding site could be attributed to some arginine residues in module LE1. The gamma2LE4-6 segment remaining in processed laminin-5 showed only a strong binding to fibulin-2. Immunological studies showed a similar partial processing in cell culture and tissues and the persistence of the released fragment in tissues. This indicated that both N-terminal regions of the gamma2 chain may have a function in vivo.

Amino Acid Sequence↗
PubMed2001

anti-bis(mu-2-ammonioethanethiolato-kappa2S:S)bis[dichloropalladium(II)] dihydrate.

Each of two square-planar Pd(II) ions in the title compound, [Pd2Cl4(mu-Haet-S)2]*2H2O (Haet = 2-ammonioethanethiolate, C2H7NS), which was obtained by rearrangement of [Pd2[Pd(aet-N,S)2]4]4+ in acidic solution, is coordinated by two bridging S atoms from two Haet ligands and by two terminal Cl atoms, forming the dinuclear structure. Since the complex is situated on a center of symmetry, the two monodentate Haet arms are located on opposite sides of the central Pd2S2 square plane, i.e. the present complex is the anti isomer. The S-C-C-N torsion angle is 177.3 (6) degrees and some intermolecular hydrogen bonds are observed.

Journal Article↗
PubMed2001

[A case of acute focal bacterial nephritis].

We report a case of acute focal bacterial nephritis (AFBN). A 30-year-old female patient visited Kyushu Rosai hospital with complaints of right flank pain and a fever of 3 days duration. She was immediately admitted, but still suffered from flank pain after 3 days of antibiotic therapy. Abdominal CT scan detected a focal mass lesion in the mid portion of the right kidney. Her clinical symptoms improved after 7 days of chemotherapy, and she was discharged. The mass lesion in the kidney disappeared after one month, she remained free of symptoms, and renal function was normal when followed up nineteen months later.

Acute Disease↗
PubMed2001

Structure-activity studies on nociceptin analogues: ORL1 receptor binding and biological activity of cyclic disulfide-containing analogues of nociceptin peptides.

Nociceptin/Orphanin FQ is an endogenous peptide ligand for the opioid receptor-like 1 (ORL1) receptor. To investigate the structural and conformational requirements of the nociceptin (NC)-receptor interaction, six cyclic analogues containing Cys disulfide linkages were designed and synthesized. Analogues cyclized at the N-terminal part, cyclo[Cys(0), Cys(7)]NC(1-13)-NH(2) (2) and cyclo[Cys(0), Cys(11)]NC(1-13)-NH(2) (4), and their corresponding linear peptides had very low activities in both the receptor binding and the GTP gamma S functional assays using human ORL1 transfected cell membranes. On the contrary, analogues cyclized at the C-terminal parts by the disulfide linkages at positions 6-10, 7-11, 7-14, and 10-14 sustained relatively high potencies in both assays. Notably, cyclo[Cys(10), Cys(14)]NC(1-14)-NH(2) (12) was found to be a potent NC agonist nearly as active as the parent peptide or NC. The maximum efficacy (Emax) of the C-terminally cyclized analogues and their linear counterparts in the GTP gamma S functional assay showed more than 94% (vs NC as 100%), suggesting that these analogues are full agonists. Analogue 12 is the first conformationally constrained NC analogue with almost full activity, and thus may serve to analyze the bioactive conformations of NC at the receptor site as well as serving as a template for more potent NC agonists.

Cell Line↗
PubMed2001

Relationship between evaluation by quantitative fatty acid myocardial scintigraphy and response to beta-blockade therapy in patients with dilated cardiomyopathy.

Predicting the effect of beta-blockade therapy on the clinical outcome of patients with dilated cardiomyopathy (DCM) is difficult prior to the initiation of therapy. Myocardial fatty acid metabolism has been shown to be impaired in patients with DCM. We examined whether the extent of myocardial injury, as assessed by iodine-123 15-( p-iodophenyl)-3- R, S-methylpentadecanoic acid (BMIPP) myocardial scintigraphy, is related to the response of patients with DCM to beta-blockade therapy. Thirty-seven patients with DCM were examined using BMIPP myocardial scintigraphy before and after 6 months of treatment with metoprolol. Myocardial BMIPP uptake (%BM uptake) was estimated quantitatively as a percentage of the total injected count ratio. The left ventricular end-diastolic and end-systolic dimensions (LVDd, LVDs) and ejection fraction (LVEF) were also evaluated. The patients were divided into two groups according to their functional improvement (>10% elevation of LVEF) after 6 months of metoprolol therapy. Twenty-eight patients responded to the therapy, while nine did not. Prior to the therapy, no significant differences in LVDd, LVDs or LVEF were observed between the responders and non-responders. However, the %BM uptake was significantly lower in the non-responders than in the responders (1.0%+/-0.2% vs 2.1%+/-0.5%, P<0.001). The %BM uptake could be used to distinguish the responders from the non-responders with a sensitivity of 0.93 and a specificity of 1.00 at a threshold value of 1.4. After the metoprolol therapy, the %BM uptake improved significantly in the responders (2.5%+/-0.5%, P<0.01) but did not change in the non-responders. These results indicate that myocardial BMIPP uptake could predict the response of DCM patients to beta-blockade therapy.

Adrenergic beta-Antagonists↗
PubMed2001

Cloning of a functional splice variant of L-type calcium channel beta 2 subunit from rat heart.

L-type Ca(2+) channels are heteromultimeric and finely tuned by auxiliary subunits in different tissues and regions. Among auxiliary subunits, beta subunit has been shown to play important roles in many functional aspects of Ca(2+) channel. Rat heart was reported to specifically express beta(2a) subunit. However, the slow inactivation rates of Ca(2+) currents recorded from recombinant Ca(2+) channels with the beta(2a) subunit, and the reported inability to detect beta(2a) subunit in rabbit heart by reverse transcription-PCR analysis raise the possibility of the existence of other beta subunits. We cloned a splice variant of beta(2) subunit from rat heart, using rapid amplification of cDNA 5' ends. The splice variant is highly similar to human beta(2c) subunit that was cloned from human ventricle. Northern blot analysis detected the rat beta(2c) subunit abundantly in rat heart and brain. The deduced amino acid sequence of the beta(2c) subunit was different from that of the beta(2a) subunit only in the N-terminal region. When the beta(2c) subunit was expressed along with alpha(1c) and alpha(2)delta subunits in baby hamster kidney cells, the inactivation rates were comparable with those from native cardiac myocytes, although those with the beta(2a) subunit were slow. Taken together, these observations suggest that the beta(2c) subunit is a functional beta(2) subunit expressed in heart and that the short N-terminal region plays a major role in modifying inactivation kinetics.

Alternative Splicing↗
PubMed2001

Tongue and jaw muscle activities during chewing and swallowing in freely behaving rabbits.

To study the function of the tongue and the coordination among jaw, tongue, and hyoid muscles during chewing and swallowing, we recorded the electromyographic activities from the masseter (Mas), digastric (Dig), mylohyoid (Myl), thyrohyoid (Thy), genioglossus (Gg) and styloglossus (Sg) muscles as well as jaw movement trajectories in the freely behaving rabbit. Three phases were identified in the chewing cycle (fast- and slow-closing and opening phases). The Gg (main tongue protruder) was active synchronously with the Dig during opening. The Sg (tongue retractor) showed two peaks in each cycle, one in the opening phase and the other in the closing phase. The latter may have a role in retracting the tongue during jaw closing. The co-contraction of the antagonists (i.e. Gg and Sg) during opening may contribute to shape the tongue to be appropriate to gather the foodstuff. In the swallowing cycle, five phases were identified, two in the closing phase and three in the opening phase. Regression analysis revealed that swallowing cycles had a longer cycle duration than that of the chewing cycles due to an extra phase (a pause) inserted in the opening phase, where there was a small co-activation in the jaw opening and closing muscles. The findings suggest that the swallowing center affects masticatory center in the central nervous system, and may also support the view that the masticatory burst timing begins with the Dig activities in the middle of the opening phase.

Animals↗
PubMed2001

Analysis of codon usage diversity of bacterial genes with a self-organizing map (SOM): characterization of horizontally transferred genes with emphasis on the E. coli O157 genome.

With increases in the amounts of available DNA sequence data, it has become increasingly important to develop tools for comprehensive systematic analysis and comparison of species-specific characteristics of protein-coding sequences for a wide variety of genomes. In the present study, we used a novel neural-network algorithm, a self-organizing map (SOM), to efficiently and comprehensively analyze codon usage in approximately 60,000 genes from 29 bacterial species simultaneously. This SOM makes it possible to cluster and visualize genes of individual species separately at a much higher resolution than can be obtained with principal component analysis. The organization of the SOM can be explained by the genome G+C% and tRNA compositions of the individual species. We used SOM to examine codon usage heterogeneity in the E. coli O157 genome, which contains 'O157-unique segments' (O-islands), and showed that SOM is a powerful tool for characterization of horizontally transferred genes.

Algorithms↗
PubMed2001

Nonsense and frameshift mutations in ZFHX1B, encoding Smad-interacting protein 1, cause a complex developmental disorder with a great variety of clinical features.

Mutations in ZFHX1B, encoding Smad-interacting protein 1 (SIP1), have been recently reported to cause a form of Hirschsprung disease (HSCR). Patients with ZFHX1B deficiency typically show mental retardation, delayed motor development, epilepsy, microcephaly, distinct facial features, and/or congenital heart disease, in addition to the cardinal form of HSCR. To investigate the breadth of clinical variation, we studied DNA samples from six patients with clinical profiles quite similar to those described elsewhere for ZFHX1B deficiency, except that they did not have HSCR. The results showed the previously reported R695X mutation to be present in three cases, with three novel mutations-a 2-bp insertion (760insCA resulting in 254fs262X), a single-base deletion (270delG resulting in 91fs107X), and a 2-bp deletion (2178delTT resulting in 727fs754X)-newly identified in the other three. All mutations occurred in one allele and were de novo events. These results demonstrate that ZFHX1B deficiency is an autosomal dominant complex developmental disorder and that individuals with functional null mutations present with mental retardation, delayed motor development, epilepsy, and a wide spectrum of clinically heterogeneous features suggestive of neurocristopathies at the cephalic, cardiac, and vagal levels.

Abnormalities, Multiple↗
PubMed2001

Annexin II overexpression correlates with stromal tenascin-C overexpression: a prognostic marker in colorectal carcinoma.

BACKGROUND: Overexpression of annexin II, a calcium-dependent phospholipid-binding protein, has been reported in various carcinomas. One of its ligands is tenascin-C, an extracellular matrix glycoprotein with predominantly antiadhesive qualities that also has been reported to be a prognostic marker for several carcinomas. In the current study, the authors investigated the correlation between the overexpression of annexin II and tenascin-C in colorectal carcinoma. METHODS: Western blot analysis of annexin II expression was examined in four human colorectal carcinoma cell lines. Using immunohistochemical methods, the authors also examined expression of annexin II and tenascin-C in 105 primary colorectal carcinoma cases. RESULTS: Although annexin II was expressed in human colon carcinoma cell lines, there was no apparent correlation between its expression level and the metastatic potential of these cell lines. The authors observed overexpression of annexin II and tenascin-C proteins in 29.5% and 49.5%, respectively, of colorectal carcinoma cases. Overexpression of annexin II was found to be correlated significantly with histologic type, tumor size, depth of invasion, and pTNM stage, whereas tenascin-C overexpression was noted to be correlated significantly with histologic type, depth of invasion, lymphatic invasion, venous invasion, lymph node metastasis, and pTNM stage. Expression of annexin II was shown to be correlated significantly with that of tenascin-C. Multivariate analysis demonstrated that annexin II and tenascin-C cooverexpression was an independent factor of poor prognosis in patients with colorectal carcinoma. CONCLUSIONS: The data from the current study suggest that both annexin II and tenascin-C are overexpressed in advanced colorectal carcinoma and that they may be related to the progression and metastatic spread of colorectal carcinoma.

Annexin A2↗
PubMed2001

Recovery of function and mass of endogenous beta-cells in streptozotocin-induced diabetic rats treated with islet transplantation.

Islet transplantation corrects chronic hyperglycemia by augmentation of insulin supply from the graft tissue, but the role of endogenous beta-cells after transplantation is not clear. In the present study, we examined endogenous beta-cell function after glucose homeostasis had been reestablished by islet graft in streptozotocin (STZ)-induced diabetic rats. Fed plasma glucose levels in diabetic rats transplanted with a large number of islets (2500 islets) into the left kidney capsule soon became lower (139.8 +/- 8.2 mg/dl) and close to the level in controls (129.7 +/- 11.3 mg/dl), and IPGTT exhibited a pattern of plasma glucose response almost identical to control. The insulin and DNA contents, islet area, and the distribution of beta-cells that were markedly deteriorated in islets of STZ rats were significantly restored in transplanted rats. The insulin release in response to glucose or alpha-ketoisocaproate was less in STZ rats, while in islets of transplanted rats the secretion recovered to levels similar to controls. On the other hand, arginine-induced insulin release was conversely hyperresponsive in STZ rats, but in transplanted rats, the response was decreased similar to controls. Thus, as the plasma glucose level normalizes, residual beta-cells show a recovery of function that cannot be accounted for by the increase in mass alone.

Animals↗
PubMed2001

ATRA-regulated Asb-2 gene induced in differentiation of HL-60 leukemia cells.

Suppressors of cytokine signaling (SOCS) proteins possess common structures, a SOCS box at the C-terminus and a SH2 domain at their center. These suppressors are inducible in response to cytokines and act as negative regulators of cytokine signaling. The ASB proteins also contain the SOCS box and the ankyrin repeat sequence at the N-terminus, but do not have the SH2 domain. Although Socs genes are directly induced by several cytokines, no Asb gene inducers have been identified. In this study, we screened the specific genes expressed in the course of differentiation of HL-60 cells, and demonstrated that ASB-2, one of the ASB proteins, was rapidly induced by all-trans retinoic acid (ATRA). Typical retinoid receptors (RARs) or retinoid X receptors (RXRs) binding element (RARE/RXRE) were presented in the promoter of the Asb-2 gene. We showed that RARalpha, one of the RARs, binds to the RARE/RXRE in the Asb-2 promoter. In addition, we demonstrated by luciferase reporter assay that this element was a functional RARE/RXRE. These findings indicate that ASB-2 is directly induced by ATRA and may act as a significant regulator, underlying such physiological processes as cell differentiation.

Adaptor Proteins, Signal Transducing↗
PubMed2001

Cell proliferation in cancer prevention; effects of preventive agents on estrogen-related endometrial carcinogenesis model and on an in vitro model in human colorectal cells.

Proto-oncogenes such as c-fos, c-jun and c-myc are known to relate to cell proliferation and differentiation. Some oriental herbal medicines like Glycyrrhizae radix or Juzen-taiho-to were found to suppress estradiol-17 beta (E2)-induced expression of c-fos/jun in uterine corpus and inhibited N-methyl-N-nitrosourea and E2-induced endometrial carcinogenesis in mice. It is suggested that the effects of such oriental drugs are exerted probably through suppression of estrogen-induced c-fos/jun expression and they are promising preventing agents for endometrial cancers. In the combined in vitro assay for cell proliferation (MTS assay) and apoptosis (DNA fragmentation) in human colorectal cancer cells (Colo 320), a number of naturally occurring chemopreventive agents such as curcumin, quercetin, auraptene, 1'-acetoxychavicol acetate (ACA) and indole-3-carbinol were shown to generate apoptosis as well as to inhibit cell proliferation. The results suggest a mode of action of these chemopreventive agents and also imply that such in vitro short term assay is useful for detection of new agents for cancer prevention.

Adenocarcinoma↗
PubMed2001

Reduced myocardial sarcoplasmic reticulum Ca(2+)-ATPase mRNA expression and biphasic force-frequency relations in patients with hypertrophic cardiomyopathy.

BACKGROUND: The relationship between left ventricular (LV) contractile functional reserve and gene expression of Ca(2+)-handling proteins in patients with hypertrophic cardiomyopathy (HCM) remains to be clarified. METHODS AND RESULTS: We calculated the maximum first derivative of LV pressure (LV dP/dt(max)) and the LV pressure half-time (T(1/2)) during pacing in 14 patients with nonobstructive HCM (LV ejection fraction >55%) and 7 control subjects. Endomyocardial tissue was obtained, and mRNA levels of sarcoplasmic reticulum Ca(2+)-ATPase (SERCA2), ryanodine receptor-2, phospholamban, calsequestrin, and Na(+)/Ca(2+) exchanger were quantified by use of a real-time quantitative reverse transcription-polymerase chain reaction method. Group A consisted of 7 HCM patients who showed a progressive rise in the LV dP/dt(max) with increased heart rate. Group B consisted of 7 HCM patients in whom the heart rate-LV dP/dt(max) relation was biphasic at physiological pacing rates. Both the mean maximal wall thickness and the LV hypertrophy score in group B were greater than in group A (20+/-5 versus 15+/-3 mm and 7+/-1 versus 5+/-2 points, respectively). SERCA2 mRNA levels were significantly lower in group B (SERCA2/GAPDH ratio 0.34+/-0.15) compared with group A (0.72+/-0.27) and control subjects (0.85+/-0.47), whereas the mRNA expression of ryanodine receptor-2, phospholamban, calsequestrin, and Na(+)/Ca(2+) exchanger were similar in all groups. CONCLUSIONS: These results suggest that downregulation of SERCA2 mRNA, resulting in altered Ca(2+) handling, may contribute to impaired LV contractile reserve in HCM patients with severe hypertrophy, even in the absence of detectable baseline systolic dysfunction.

Adult↗
PubMed2001

Crystallization and preliminary X-ray analysis of catalase-peroxidase from the halophilic archaeon Haloarcula marismortui.

Catalase-peroxidases are bifunctional enzymes found in many microorganisms. Crystals of catalase-peroxidase from the halophilic archaeon Haloarcula marismortui were obtained using the hanging-drop vapour-diffusion method. The rhombic plate-shaped crystals were grown from purified protein solution using (NH(4))(2)SO(4) as precipitant at 293 K. The crystal belongs to the monoclinic system, space group C2, and diffracted beyond 2.0 A resolution.

Archaeal Proteins↗
PubMed2001

Impact of genetic polymorphisms of 17-hydroxylase cytochrome P-450 (CYP17) and steroid 5alpha-reductase type II (SRD5A2) genes on prostate-cancer risk among the Japanese population.

Steroid hormones, especially testosterone, play important roles in the carcinogenesis of prostate cancer, and several studies have reported changes in risk with polymorphisms of genes involved in steroid metabolism. One example is the CYP17 gene, which has a polymorphic T-to-C substitution in the 5'-untranslated region giving rise to A1 (T) and A2 (C) alleles. Steroid 5alpha-reductase type II (SRD5A2), which converts testosterone to the metabolically more active dihydrotestosterone, exhibits 2 polymorphisms: V89L, which substitutes leucine for valine at codon 89, and A49T, which substitutes threonine for alanine at codon 49. We therefore designed a case-control study of 105 prostate-cancer patients and 210 controls with benign prostatic hyperplasia for the purpose of investigating the association between prostate-cancer risk and polymorphisms in the SRD5A2 and CYP17 genes among the Japanese. The frequency of the CYP17 A2/A2 genotype in cases (18.8%) was higher than in controls (14.5%). Compared with the A1/A1 genotype, the odds ratio for the A2/A2 genotype was 2.39 (95% confidence interval 1.04-5.46, p = 0.04). The frequency of the SRD5A2 LL genotype in cases (29.3%) was also slightly higher than in controls (24.6%), but this was not significant. Regarding the A49T polymorphism of SRD5A2, we could not detect the T allele in any of the examined samples. These data suggest a significant association between the CYP17 polymorphism and prostate-cancer risk among the Japanese.

3-Oxo-5-alpha-Steroid 4-Dehydrogenase↗