Biomedical subjects

A Shimizu

Publications and source records attributed to A Shimizu.

At least 55 records · Page 3Linked to original sources

PubMed2001

Eosinophilic peroxidase deficiency: Identification of a point mutation (D648N) and prediction of structural changes.

ABSTRACT Hereditary eosinophil peroxidase (EPO; EC 1.11.1.7) deficiency is a rare abnormality without clinical symptoms characterized by decreased or absent peroxidase activity and decreased volume of the granule matrix in eosinophils. Nearly 100 cases have been reported, but a specific mutation has been reported in only one case. We report the genetic analysis of an EPO-deficient subject and his family. The case was found by automated blood analyzer. Sequencing of the entire coding region of the EPO gene disclosed a novel mutation, a 2060 G-A transition (g. 2060G>A) causing an amino acid change from aspartic acid to asparagine (D648N). Both the son and daughter of the propositus inherited the G-A transition, and in vitro expression experiments suggest this transition is responsible for the deficiency. We then analyzed the location of the affected amino acid within this molecule using a structural model of EPO based on myeloperoxidase (MPO). Asn648 is on the inside of the molecule; changing D to N would cause loss of the electrostatic interaction with Arg146 which is crucial for disulfide bonds of the light chain in the N terminus.

Amino Acid Substitution↗

PubMed2001

Fibroblast growth factor receptor 3 lacking the Ig IIIb and transmembrane domains secreted from human squamous cell carcinoma DJM-1 binds to FGFs.

The fibroblast growth factor receptors (FGFRs) are a family of transmembrane tyrosine kinases that play a key role in cell growth and tumorigenesis in response to FGFs. FGFR complexity is increased by the existence of additional isoforms generated by alternative mRNA splicing. We identified that the transcript FGFR3DeltaTM, an alternatively spliced isoform of FGFR3 lacking exons encoding the C-terminal half of Ig III (IIIb) and transmembrane domains, is expressed in the human squamous carcinoma cell line DJM-1. To determine whether FGFR3DeltaTM has the potential to be secreted, we analyzed the protein expression in CHOK1 cells transfected with FGFR3DeltaTM cDNA and DJM-1 cells. Western blot analysis revealed that FGFR3DeltaTM protein was secreted, N-glycosylated, and dimerized by an intermolecular disulfide bond. Cross-linking experiments showed that FGF1 and FGF2 were able to bind to FGFR3DeltaTM, suggesting that the loss of the Ig IIIb domain may confer upon FGFR3DeltaTM the ability to bind to FGF2.

Alternative Splicing↗

PubMed2001

Correlation of genetic etiology with response to beta-adrenergic blockade among symptomatic patients with familial long-QT syndrome.

Mutations in any of the five genes KCNQ1, KCNH2, KCNE1, KCNE2, and SCN5A can be responsible for familial long QT syndrome (LQTS), an arrhythmogenic disorder that entails a high risk of sudden death. beta-Adrenergic blocking agents are the first therapeutic choice, and 80% of patients treated with these agents show symptomatic relief; however the remaining 20% do not respond well. We previously performed a nationwide analysis of familial long QT syndrome (LQTS) in Japan and identified 32 mutations in the KCNQ1 and KCNH2 genes. In the present retrospective study, we found that patients carrying mutations in the KCNQ1 gene responded better to beta-adrenergic blocking agents than those with KCNH2 mutations (12 of 13 vs 1 of 5; P = 0.0077, Fisher's exact test). This is a good example of the power of genetic diagnosis to direct the selection of appropriate therapy for patients with diseases of heterogeneous genetic etiology.

Adolescent↗

PubMed2001

Vascular endothelial growth factor enhances glomerular capillary repair and accelerates resolution of experimentally induced glomerulonephritis.

Vascular endothelial growth factor (VEGF) regulates angiogenesis through endothelial cell proliferation and plays an important role in capillary repair in damaged glomeruli. We tested the hypothesis that VEGF might be beneficial in rats with severe glomerular injury in glomerulonephritis (GN) based on its angiogenic and vascular remodeling properties. Acute GN with severe glomerular destruction was induced in rats by injection of anti-Thy-1.1 antibody (day 0) and Habu-snake venom (day 1). Rats were intraperitoneally injected with recombinant human VEGF(165) (10 microg/100 g body wt/day) or vehicle from day 2 to day 9, and monitored changes in glomerular capillaries, development of glomerular inflammation, and progression to glomerular sclerosis after acute glomerular destruction in both groups. Rats that received anti-Thy-1.1 antibody and Habu-snake venom showed severe mesangiolysis and marked destruction of capillary network on day 2. VEGF was expressed on glomerular epithelial cells, proliferating mesangial cells, and some infiltrating leukocytes, and VEGF(165) protein levels increased in damaged glomeruli during day 5 to day 7. Normal, damaged, and regenerating glomerular endothelial cells expressed VEGF receptor flk-1. However, endothelial cell proliferation and capillary repair was rare in vehicle-treated rats with severe glomerular damage, which progressed to global sclerosis and chronic renal failure by week 8. In contrast, in the VEGF-treated group, VEGF(165) significantly enhanced endothelial cell proliferation and capillary repair in glomeruli by day 9 (proliferating endothelial cells: VEGF(165), 4.3 +/- 1.1; control, 2.2 +/- 0.9 cells on day 7, P < 0.001; and glomerular capillaries: VEGF(165), 24.6 +/- 4.8; control, 16.9 +/- 3.4 capillaries on day 7, P < 0.01). Thereafter, damaged glomeruli gradually recovered after development of capillary network by week 8, and significant improvement of renal function was evident in the VEGF-treated group during week 8 (creatinine: VEGF(165), 0.3 +/- 0.1; control, 2.6 +/- 0.9 mg/dl, P < 0.001; proteinuria: VEGF(165), 54 +/- 15; control, 318 +/- 60 mg/day, P < 0.001). We conclude that the beneficial effect of VEGF(165) in severe glomerular injury in GN emphasizes the importance of capillary repair in the resolution of GN, and may allow the design of new therapeutic strategies against severe GN.

Animals↗

PubMed2001

Dicationic dithiocarbamate carbapenems with anti-MRSA activity.

A new class of 1 beta-methylcarbapenems bearing a doubly quaternarized 1,4-diazabicyclooctane (DABCO) substituted dithiocarbamate moiety at the C-2 side chain was prepared, and the biological profiles of the compounds, including in vitro and in vivo anti-MRSA activity and DHP-I susceptibility, were evaluated to identify a carbapenem derivative that was superior to BO-3482 (1). As a result, we discovered a 1 beta-methyl-2-[4-(4-carbamoylmethyl-1,4-diazabicyclo[2,2,2]octanediium-1-yl)methyl-1,2,3,6-tetrahydropyridinylthiocarbonylthio]carbapenem, 14a showing greater than 2-fold better anti-MRSA activity in a mouse infection model and 3-fold better DHP-I susceptibility as compared with BO-3482 (1).

Animals↗

PubMed2001

The IL-7 receptor controls the accessibility of the TCRgamma locus by Stat5 and histone acetylation.

The IL-7 receptor (IL-7R) plays critical roles in expansion and V(D)J recombination during lymphocyte development. Here we demonstrate that cytokine stimulation rapidly recruits Stat5 and transcriptional coactivators to the Jgamma germline promoter and induces histone acetylation, germline transcription, and accessibility in Ba/F3 cells. We also show that histone acetylation of the TCRgamma locus is significantly reduced in IL-7R-deficient thymocytes and that the introduction of active Stat5 restores the histone acetylation and accessibility of the locus. Furthermore, treatment with histone deacetylase inhibitor recovers the histone acetylation and accessibility in IL-7R-deficient thymocytes. Therefore, these results suggest that Stat5 may recruit the transcriptional coactivators to the Jgamma germline promoter and control the accessibility of the TCRgamma locus by histone acetylation.

Acetylation↗

PubMed2001

Stabilization of mutant Cu/Zn superoxide dismutase (SOD1) protein by coexpressed wild SOD1 protein accelerates the disease progression in familial amyotrophic lateral sclerosis mice.

Transgenic mice carrying familial amyotrophic lateral sclerosis (FALS)-linked mutant Cu/Zn superoxide dismutase (SOD1) genes such as G93A (G93A-mice) and G85R (G85R-mice) genes develop limb paresis. Introduction of human wild type SOD1 (hWT-SOD1) gene, which does not cause motor impairment by itself, into different FALS mice resulted in different effects on their clinical courses, from no effect in G85R-mice to acceleration of disease progression in G93A-mice. However, the molecular mechanism which causes the observed difference, has not been clarified. We hypothesized that the difference might be caused by the stability of mutant SOD1 proteins. Using a combination of mass spectrometry and enzyme-linked immunosorbent assay, we found that the concentration of G93A-SOD1 protein was markedly elevated in tissues of transgenic mice carrying both G93A- and hWT-SOD1 genes (G93A/hWT-mice) compared to that in G93A-mice, and also found that the concentration of G93A-SOD1 protein had a close relation to the disease duration. The concentration of metallothionein-I/II in the spinal cord, reflecting the degree of copper-mediated oxidative stress, was highest in G93A/hWT-mice, second in G93A-mice, and normal in the mice carrying hWT-SOD1 gene. These results indicated that the increase of G93A-SOD1 protein was responsible for the increase of oxidative stress and disease acceleration in G93A/hWT-mice. We speculate that coexpression of hWT-SOD1 protein is deleterious to transgenic mice carrying a stable mutant such as G93A-SOD1, because this mutant protein is stabilized by hWT-SOD1 protein, but not to transgenic mice carrying an unstable mutant such as G85R-SOD1, because this mutant protein is not stabilized by hWT-SOD1.

Amyotrophic Lateral Sclerosis↗

PubMed2001

Primary cutaneous nocardiosis due to Nocardia nova in a healthy woman.

We describe a 68-year-old healthy woman with an unusual skin manifestation of mycetoma. A dark reddish erythematous plaque was present on the dorsum of the left hand for over 10 years. A skin biopsy revealed sulphur granules in the abscess, and Nocardia nova was identified from the specimen. Treatment with dapsone resulted in significant improvement. We review the clinical features of cutaneous N. nova infections.

Aged↗

PubMed2001

Prolongation of activation-recovery interval over a preexcited region before and after catheter ablation in patients with Wolff-Parkinson-White syndrome.

INTRODUCTION: Preexisting changes in repolarization properties play an important role in T wave abnormalities (cardiac memory) after ablation in patients with Wolff-Parkinson-White (WPW) syndrome. However, no report has provided direct evidence for prolongation of action potential duration (APD) over a preexcited region before and after ablation. METHODS AND RESULTS: We studied 10 patients with ventricular preexcitation due to a left-sided accessory pathway (AP) (group M) and 12 patients with concealed left-sided AP (group C) to clarify prolongation of APD using activation-recovery intervals (ARIs) from epicardial and endocardial unipolar electrograms in patients with WPW syndrome. ARI was calculated from unipolar electrograms at the His bundle and the coronary sinus adjacent to the AP during atrial pacing (100 beats/min) before and 30 minutes after ablation. Before ablation, ARIs at the AP site were significantly longer in group M than in group C (255+/-21 msec vs 211+/-24 msec; P < 0.01), whereas ARIs at the His bundle did not differ between the two groups (255+/-20 msec vs 245+/-27 msec; P = NS). After ablation, group M showed no significant changes in ARIs at the AP and His bundle (256+/-19 msec and 253+/-15 msec) compared with before ablation. CONCLUSION: We found by direct analysis of ARIs from the epicardium that APD prolongation over the preexcited region was present before catheter ablation and persisted after catheter ablation. The gradual changes in repolarization properties, including APD prolongation after discontinuation of AP, may be one mechanism of cardiac memory after catheter ablation in patients with WPW syndrome.

Action Potentials↗

PubMed2001

Prospective study of laparoscopic findings with regard to the development of hepatocellular carcinoma in patients with hepatitis C virus-associated cirrhosis.

BACKGROUND: The laparoscopic findings of hepatocarcinogenesis are not well defined. The purpose of this prospective study was to evaluate the predictive value of laparoscopic findings with regard to the development of hepatocellular carcinoma (HCC) in patients with hepatitis C virus (HCV)-associated cirrhosis. METHODS: One hundred nineteen patients with HCV-associated cirrhosis who underwent laparoscopy were enrolled in this study. Ten laparoscopic variables, including degree of development and size of regenerating nodules, irregularity of regenerating nodules, and size of both hepatic lobes, were measured. The predictive value of each finding for the development of HCC was investigated by using univariate and multivariate analyses. RESULTS: HCC developed in a total of 42 of the 119 patients (35.3%) during a mean follow-up period of 62.9 months. The degree of regenerating nodules, the presence of irregular regenerative nodules, and atrophic right lobe were significant predictive factors for HCC with univariate analysis. In particular, 67.1% of patients with irregular regenerative nodules had HCC develop within 5 years. Multivariate analysis revealed that irregular regenerative nodules (relative risk 6.32, p = 0.012), the degree of regenerative nodules (relative risk 4.78, p = 0.029), and atrophic right lobe (relative risk 3.87, p = 0.048) were independent predictive factors. CONCLUSIONS: Morphologic observation of the liver surface by laparoscopy is important and provides information on factors that are statistically significant early predictors of the development of HCC.

Adult↗

PubMed2001

Interferon-gamma production in peripheral lymphocytes of patients with tinea pedis: comparison of patients with and without tinea unguium.

The precise mechanism of the host defense that protects the nail from dermatophyte invasion is not known. Recent immunological findings in dermatophytosis suggest the hypothesis that the T helper 1 (Th1) response may play a role in protecting the nail from dermatophyte invasion. Our present study focused on interferon-gamma (IFN-gamma) release in patients with tinea pedis with or without tinea unguium, and pathogenesis of tinea unguium is discussed in relation to the association with a possible deficiency of Th1 response in the host defense mechanism. The production of IFN-gamma by peripheral blood mononuclear cells from the patients with tinea unguium in response to stimulation with trichophytin was not impaired in contrast to that from the patients without tinea unguium. Comparable lymphocyte proliferation to trichophytin was observed in both groups. Normal healthy persons with no clinical evidence of tinea could be divided into two groups based on lymphocyte proliferation and IFN-gamma production in response to trichophytin: high responder and low responder, with high responders being correlated with a clinical history of previous tinea pedis. In this study, a lack of a Th1 response to dermatophyte antigen was not shown in patients with tinea unguium by measuring the release of IFN-gamma, which plays a role in the effector phase of the delayed-type hypersensitivity reaction. A deficiency in the Th1 response to dermatophyte antigen, therefore, does not appear to play an important role in the establishment of tinea unguium.

Female↗

PubMed2001

An experimental sclerosing encapsulating peritonitis model in mice.

BACKGROUND: Sclerosing encapsulating peritonitis (SEP) is a life-threatening complication of continuous ambulatory peritoneal dialysis. To elucidate the mechanism and develop treatments for this condition, an experimental SEP model in mice was constructed. METHODS: C57BL/6 mice were administered 0.3 ml of 0.1% chlorhexidine gluconate and 15% ethanol dissolved in saline, intraperitoneally, on a daily basis for 56 days (group 1, n=15). A control group of C57BL/6 mice were administered 0.3 ml of phosphate-buffered saline only in the same manner (group 2, n=15). The mice were sacrificed on days 3, 7, 21, 56 and were prepared for histological analysis. RESULTS: In group 1, all mice had developed macroscopic evidence of SEP 56 days after the injection. Microscopically we observed peritoneal fibrosis and an increase in infiltrates of mononuclear cells over time. The peritoneal fibrosis reached the chronic inflammatory stage by 56 days after the injection. CONCLUSION: We have developed a convenient experimental model of SEP in mice, which may be useful in elucidating the pathogenesis of SEP and in establishing possible treatments.

Animals↗

PubMed2001

Tolerance to solid organ transplants through transfer of MHC class II genes.

Donor/recipient MHC class II matching permits survival of experimental allografts without permanent immunosuppression, but is not clinically applicable due to the extensive polymorphism of this locus. As an alternative, we have tested a gene therapy approach in a preclinical animal model to determine whether expression of allogeneic class II transgenes (Tg's) in recipient bone marrow cells would allow survival of subsequent Tg-matched renal allografts. Somatic matching between donor kidney class II and the recipient Tg's, in combination with a short treatment of cyclosporine A, prolonged graft survival with DR and promoted tolerance with DQ. Class II Tg expression in the lymphoid lineage and the graft itself were sequentially implicated in this tolerance induction. These results demonstrate the potential of MHC class II gene transfer to permit tolerance to solid organ allografts.

Animals↗

PubMed2001

Practical synthesis of a 1beta-methylcarbapenem, J-111,225, using 4-mercapto-2-[4-(N-methylaminomethyl)phenyl]pyrrolidine as a precursor.

An effective and practical procedure for the synthesis of J-111,225 (1), a new 1beta-methylcarbapenem, was developed using 4-mercapto-2-14-(N-methylaminomethyl)phenyl]pyrrolidine (2a) as a precursor. The coupling reaction of 2a with p-nitrobenzyl (PNB)-protected 1beta-methylcarbapenem enolphosphate 3a and successive removal of PNB group afforded J-111,225 (1) in significantly increased yield compared to the ordinary procedure using a C-2 side-chain thiol with amino-protective groups.

Anti-Infective Agents↗

PubMed2001

Activation-recovery intervals of 12-lead electrocardiograms before and after catheter ablation in patients with Wolff-Parkinson-White syndrome.

Preexcitation in Wolff-Parkinson-White syndrome (WPW) has been reported to induce long-lasting changes in ventricular recovery properties. However, there has not been a report concerning changes in the activation-recovery interval (ARI) in 12-lead ECGs before and after catheter ablation (CA) in patients with WPW syndrome. The present study compared changes in ARIs from 12-lead ECGs with those from body surface unipolar leads before and after CA to examine whether ARIs from limb leads of 12-lead ECGs provide useful information on changes in recovery properties in addition to the ARIs from precordial leads. The study population consisted of 27 manifest WPW patients with a left- (n=18, group A) or right-sided accessory pathway (n=9, group B). ARIs in leads I, II, and III were strongly correlated with those in unipolar leads over the left lateral, left lower, and right lower chest, respectively. ARIs in leads aVR, aVL, and aVF showed a significant correlation with those in unipolar leads over the right upper, left upper, and lower anterior chest, respectively. These correlations were maintained before and after CA. Furthermore, in group A, ARIs in lead V1 tended to increase on day 7 post CA compared with before CA and on day 1. In group B, ARIs in lead III significantly decreased on day 7 compared with before CA and on day 1. These findings suggest that ARIs from the limb leads of 12-lead ECGs may represent those from unipolar leads of a particular area over the body surface, and that ARIs from 12-lead ECGs may provide useful quantitative information on changes in recovery properties before and after CA in patients with manifest WPW syndrome.

Adolescent↗

PubMed2001

Antimicrobial susceptibility of Staphylococcus intermedius isolated from healthy and diseased dogs.

A total of 90 strains of Staphylococcus intermedius isolated from dogs were examined for antimicrobial susceptibility. There were no significant differences in the distribution patterns of MICs between strains from 1982 to 1985 and those from 1999, and between strains from healthy dogs and those from diseased dogs. All of the strains were susceptible to ABPC, DMPPC, CEX, TDM, ERFX, BFLX, and FF at concentrations of 0.05 to 6.25 microg/ml. The MICs of OTC, KM, EM, AIV-TS, and LCM were distributed in a broad range of 0.1 to >100 microg/ml, indicating the existence of resistant as well as susceptible populations of S. intermedius. Thirty-three strains (36.7%) were resistant to one or more anitmicrobial agents such as OTC (n=32), KM (n=9), EM (n=7), AIV-TS (n=7), and LCM (n=7).

Animals↗

PubMed2001

Functional defect of B lymphocytes in a patient with selective IgM deficiency associated with systemic lupus erythematosus.

Selective IgM deficiency (SIgMD) is a rare primary immunodeficiency disease, which is found in some patients with autoimmune diseases. The pathogenesis of SIgMD and the relationship of these diseases have remained unclear. The absence of secreted IgM was recently reported to accelerate the development of autoimmune diseases in lupus-prone lymphoproliferative (Ipr) mice. The reduction of secreted IgM production may relate with the progression of autoimmune diseases in human. We present a case of SIgMD associated with systemic lupus erythematosus (SLE), and examined the function and the IgM heavy chain gene of patient's lymphocytes. The number and the surface IgM expression of the patient's B cells were normal. In vitro stimulation of peripheral mononuclear cells by recombinant IL-2 and a B cell activator, Staphylococcus aureus Cowan strain I, could not overcome the reduction of IgM production, although the secreted form of IgM mRNA was detected. Sequence analysis of the IgM heavy chain gene and the IgM mRNA revealed no mutation or deletion. These findings suggested that SIgMD in this case was involved in the abnormality during B cell maturation. Further analysis is required to reveal the pathogenesis of SIgMD associated with SLE.

Antibody Formation↗

PubMed2001

The elevation of natural killer cell activity induced by laughter in a crossover designed study.

The elevation of natural killer cell activity (NKCA) by laughter was not confirmed due to incomplete methodology of previous studies although positive emotion is believed to be favorable for health. To verify NKCA elevation by laughter in a crossover design, we measured NKCA before and after watching films, presenting 75-min comic film and non-emotional control film at different days to the same 21 healthy male subjects. Electromyogram of left major zygomatic muscle was obtained during the films to quantify the magnitude of laughter as an index of emotional expression. As indices of emotional experience, the self-rated pleasantness of the comic film and mood state before and after film were measured using visual analogue scale and Profiles of Mood State (POMS), respectively. The comic film significantly elevated NKCA (26.5-29.4%, p<0.05), whereas the control film did not (27.1-24.8%, not significant). This is the first study to demonstrate NKCA elevation by laughter in a crossover designed study. To examine the contribution of experiential and expressive aspects of laughter to NKCA elevation, correlation of NKCA elevation with the self-rated pleasantness, mood scores before and after comic film and the magnitude of laughter was statistically tested. We found that NKCA elevation was negatively correlated with the scores of negative mood scales of POMS while NKCA elevation had no significant correlation with self-rated pleasantness and the magnitude of laughter. Further group analysis revealed that high scores of depression and anger-hostility suppressed NKCA elevation by laughter. We also found that NKCA before and after comic film had tendency of correlation with self-rated pleasantness of the comic film while NKCA had no correlation with the magnitude of laughter. These findings suggest that NKCA elevation and NKCA before and after comic film seem to be related with the experiential aspects of laughter rather than with the expressive aspects.

Adolescent↗