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Biomedical subjects

R Fukuda

Publications and source records attributed to R Fukuda.

At least 19 recordsLinked to original sources
PubMed2000

Myopathy phenotype of transgenic mice expressing active site-mutated inactive p94 skeletal muscle-specific calpain, the gene product responsible for limb girdle muscular dystrophy type 2A.

A defect of the gene for p94 (calpain 3), a skeletal muscle-specific calpain, is responsible for limb girdle muscular dystrophy type 2A (LGMD2A), or 'calpainopathy', which is an autosomal recessive and progressive neuromuscular disorder. To study the relationships between the physiological functions of p94 and the etiology of LGMD2A, we created transgenic mice that express an inactive mutant of p94, in which the active site Cys129 is replaced by Ser (p94:C129S). Three lines of transgenic mice expressing p94:C129S mRNA at various levels showed significantly decreased grip strength. Sections of soleus and extensor digitorum longus (EDL) muscles of the aged transgenic mice showed increased numbers of lobulated and split fibers, respectively, which are often observed in limb girdle muscular dystrophy muscles. Centrally placed nuclei were also frequently found in the EDL muscle of the transgenic mice, whereas wild-type mice of the same age had almost none. There was more p94 protein produced in aged transgenic mice muscles and it showed significantly less autolytic degradation activity than that of wild-type mice. Although no necrotic-regenerative fibers were observed, the age and p94:C129S expression dependence of the phenotypes strongly suggest that accumulation of p94:C129S protein causes these myopathy phenotypes. The p94:C129S transgenic mice could provide us with crucial information on the molecular mech-anism of LGMD2A.

Animals↗
PubMed2000

Diagnostic accuracy of a new non-invasive enzyme immunoassay for detecting Helicobacter pylori in stools after eradication therapy.

BACKGROUND: Helicobacter pylori eradication therapy has been commonly performed for patients with peptic ulcer. An inexpensive, reliable, non-invasive test would be useful for evaluation of the effectiveness of eradication therapy. AIM: To evaluate the diagnostic potential of a new non-invasive enzyme immunoassay (HpSA) for H. pylori antigen in stools. METHODS: A total of 112 peptic ulcer patients with H. pylori infection (82 male, 30 female; age range 22-81 years, mean 54 years) received a course of eradication therapy. Four weeks after the end of the therapy, stool samples were collected from all patients and tested using the HpSA. The diagnostic accuracy of the HpSA EIA was evaluated in comparison with the results of a 13C-urea breath test. RESULTS: The diagnostic sensitivity of HpSA EIA after eradication therapy was 90%, the specificity 98%, the positive predictive value 82% and the negative predictive value 99%. CONCLUSION: The HpSA stool test is potentially useful for the diagnosis of H. pylori infection 4 weeks after the end of eradication therapy.

Adult↗
PubMed2000

Role of hepatitis B virus in non-B, non-C chronic liver disease: in vitro proliferation and interferon-gamma production of peripheral blood mononuclear cells in response to hepatitis B core antigen and its relation to hepatitis activity.

OBJECTIVE: Although hepatitis B virus (HBV) DNA has been detected in the sera of patients with chronic liver disease with neither hepatitis B surface antigen nor antihepatitis C virus antibody (non-B, non-C [NBNC] CLD), whether HBV has some pathogenic role in NBNC CLD has not been made clear. METHODS: To investigate the significance of HBV DNA in NBNC CLD, we performed in vitro stimulation assays of peripheral blood mononuclear cells (PBMCs) in response to hepatitis B core antigen (HBcAg) in 17 NBNC CLD patients. RESULTS: HBV DNA with an 8-nucleotide deletion in the core promoter region was detected in 13 (76%) of the 17 patients by nested polymerase chain reaction. Interferon-gamma (IFN-gamma) production and proliferation of PBMCs of HBV DNA-positive patients showed a significant increase in response to HBcAg. The histological activity of hepatitis was also found to be significantly associated with the magnitude of IFN-gamma production and proliferation of PBMCs in response to HBcAg. Although five (38%) of the 13 HBV DNA-positive NBNC CLD patients had anti-HBs and/or anti-HBc, there was no difference in response of PBMCs to HBcAg between the HBV DNA-positive and -negative groups. CONCLUSION: Our observation suggests that HBV may have a pathogenic role in HBV DNA-positive NBNC CLD, even in those patients without any serological markers of HBV.

Adult↗
PubMed1999

Characterization of cleavage enzymes for sterol regulatory element binding protein in hamster liver microsomes.

Sterol regulatory element binding proteins (SREBP-1 and SREBP-2) are the key transcription factors for the regulation of the cellular cholesterol level. To identify proteolytic enzymes for SREBPs, a fluorogenic peptide substrate, MOCAc-GRSVLSFK(Dnp)rr-NH2, was synthesized according to the proposed cleavage site of human SREBP-2. In microsome fractions from hamster liver, we found a peptidase activity inhibitable by the synthetic inhibitor Ac-GRSVL-aldehyde with an IC50 of 40 nM. This peptidase separated into three peaks of approximately 400 kDa, 60 kDa, and 30 kDa (Mp400, Mp60 and Mp30 respectively) upon gel permeation chromatography. Mp30 was purified to apparent homogeneity with an Mr of 32 kDa. The partial amino acid sequence of Mp30 possessed homology to cathepsin B (EC 3.4.22.1). A 109 kDa protein band on SDS-PAGE which corresponded to Mp400 exhibited homology to neprilysin (EC 3.4.24.11) in partial amino acid sequence. These findings suggest several degradative pathways for SREBP in liver microsome membranes.

Amino Acid Sequence↗
PubMed1999

Serologically silent hepatitis B virus coinfection in patients with hepatitis C virus-associated chronic liver disease: clinical and virological significance.

Frequent coinfection of surface antigen-negative hepatitis B virus (silent HBV) in hepatitis C virus (HCV)-associated chronic liver disease (CLD) has been reported. The clinical and virological significance of silent HBV infection was investigated in 65 patients with HCV-associated CLD who subsequently received interferon (IFN) therapy. HBV DNA was detected in 34 (52.3%) patients by a nested polymerase chain reaction (PCR). Virologically, all of the 34 patients were found to have HBV with an eight-nucleotide deletion in the core promoter. Coinfection of silent HBV was more frequent with HCV genotype 1b than in 2a (64.3% vs. 28.6%, P<.01). With HCV genotype 1b, the serum RNA level was significantly higher (> or =10(6) copies per milliliter vs. < or =10(5) copies per milliliter) in patients with silent HBV than those without coinfection (P<.01). Clinically, silent HBV was associated with a higher level of serum alanine aminotransferase (158.5+/-104.8 vs. 121.8+/-78.6 IU/I; mean +/- SD) and a greater histological activity of hepatitis as evaluated by histological activity index score (9.4+/-3.8 vs. 8.6+/-4.5; mean +/- SD), although it was not statistically significant. Silent HBV was also associated with poor efficacy of IFN therapy (P<.01). The results suggest that silent HBV has some promoting effect for HCV replication, at least for HCV genotype 1b, and may affect the histological activity of hepatitis and IFN response in HCV-associated CLD.

Adult↗
PubMed1999

Growth inhibitory effects of somatostatin on human leukemia cell lines mediated by somatostatin receptor subtype 1.

Reverse transcription polymerase chain reaction analysis revealed that only somatostatin receptor (SSTR) 1 mRNA was expressed in Ball-1 B-, Jurkat T-, and HL60 leukemia cell lines. In contrast, human normal mononuclear cells expressed the mRNA of all five subtypes of SSTR, although the expression level of SSTR1 was the highest. A binding study, revealed that [125I]-somatostatin bound specifically to HL60 cells and this binding was inhibited concentration-dependently by unlabeled somatostatin (SS). A [3H]thymidine incorporation study showed that SS significantly and concentration-dependently inhibited HL60 and BALL-1 leukemia cell growth. Furthermore, this inhibition of leukemia cell growth was associated with reduces c-fos gene expression. These data indicate that leukemia cells express SSTR1 and SS reduce c-fos gene expression with resultant suppression of leukemia cell growth, possibly mediated by the SSTRI.

Cell Division↗
PubMed1999

Prevalence of non-ulcer dyspepsia in the Japanese population.

BACKGROUND: Non-ulcer dyspepsia (NUD) is one of the most frequently encountered disorders in general practice in Western countries. The prevalence of this disorder in the Japanese, however, has not been fully investigated. This study is designed to clarify the characteristics and prevalence of dyspepsia in the Japanese. METHODS: The subjects were 1139 people who visited our institutes for their annual medical check up for gastric cancers. After routine medical examination, all subjects were asked standardized questions in order to check for the presence of any symptoms suggesting dyspepsia. RESULTS: The results of the study showed that dysmotility-like dyspepsia, characterized by the presence of nausea, fullness and early satiety, is the most frequently observed dyspepsia in Japanese and that this type of dyspepsia decreases with age. Ulcer-like dyspepsia, which is the major type of dyspepsia in Western countries, is the least frequently experienced dyspepsia in the Japanese. CONCLUSIONS: This study clarified that NUD is also one of the most prevalent disorders in the Japanese, although its characteristics may be somewhat different from those in Western countries.

Adult↗
PubMed1999

Effect of candesartan cilexetil (TCV-116) in rats with chronic renal failure.

BACKGROUND: Inhibition of the renin-angiotensin system by both angiotensin II type 1 receptor antagonists (AT1As) and angiotensin I-converting enzyme inhibitors (ACEIs) shows renoprotective effects in rats with chronic renal failure when treatment is started in the early phase of renal injury. In this study, we examined the renal protective effects of candesartan cilexetil (TCV-116), an AT1A, and enalapril, an ACEI, in the progressive phase of renal injury in 5/6 nephrectomized rats. METHODS: Candesartan cilexetil (1 mg/kg/day) and enalapril (10 mg/kg/day) were orally administered once a day for 4 weeks (the short-term experiment) or 16 weeks (the long-term experiment) to 5/6 nephrectomized rats beginning 15 weeks after the nephrectomy, that is, after they had already showed marked proteinuria. RESULTS: In vehicle-treated rats, proteinuria, glomerulosclerosis, and interstitial fibrosis developed. Moreover, enhanced expression of transforming growth factor-beta1 (TGF-beta1) in the injured glomeruli was observed. These adverse changes progressed with time, and in the short-term experiment, both drugs inhibited them. In the long-term experiment, the progressive proteinuria and the elevation of blood pressure were similarly attenuated by both drugs. However, candesartan cilexetil significantly inhibited the progression of glomerulosclerosis, the expression of TGF-beta1, and interstitial fibrosis, whereas enalapril did not. CONCLUSION: These results indicate that candesartan cilexetil shows potent and long-term preventive effects against the progression of previously developed renal injury.

Angiotensin Receptor Antagonists↗
PubMed1999

A case of a malignant melanoma with late metastases 16 years after the initial surgery.

We report a case of a pulmonary metastasis 16 years after the initial surgery for a malignant melanoma. The patient was a 58-year-old Japanese man. In 1976, he had a pigmented skin lesion with a diameter of 8 mm on his right third finger. He received an amputation of the finger and a dissection of the right axillary. Histological examinations of the tumor revealed a feature of a malignant melanoma with infiltration of the papillary layers of the dermis, 1.5 mm in thickness. The histological subtype was considered to be an acral lentiginous melanoma with a mixed spindle-epithelioid cell pattern. There was no regional lymph node metastasis. In December 1992, when he was 74-years-old, a round tumor in the left lower lung was discovered by chest radiography. In February 1993, he received a left lower lobectomy of the lung. Histological examination revealed a feature of a malignant melanoma with predominantly epithelioid cells and this was considered to be a metastasis from the initial skin lesion. Five months after the lobectomy, he died from a hemorrhage of a metastatic brain tumor. This case indicated the importance of periodic, life-long follow-up in treating malignant melanomas.

Amputation, Surgical↗
PubMed1999

Functional domain structure of human heterochromatin protein HP1(Hsalpha): involvement of internal DNA-binding and C-terminal self-association domains in the formation of discrete dots in interphase nuclei.

Human heterochromatin protein HP1(Hsalpha) possesses two evolutionarily conserved regions in the N- and C-terminal halves, so-called chromo and chromo-shadow domains, and DNA-binding domain in the internal non-conserved region. Here, to examine its in vivo properties, we expressed HP1(Hsalpha) as a fusion product with green fluorescent protein in human cells. HP1(Hsalpha) was observed to form discrete dots in interphase nuclei and to localize in the centromeric region of metaphase chromosomes by fluorescence microscopy. Interestingly, this dot-forming activity was also found in the N-terminal half retaining the chromo and DNA-binding domains and in the C-terminal chromo-shadow domain. However, the chromo domain alone stained nuclei homogeneously. To correlate this dot-forming activity with self-associating activity in vitro, the chromo and chromo-shadow domain peptides were independently expressed in Escherichia coli, affinity purified, and chemically cross-linked with glutaraldehyde. In a SDS-polyacrylamide gel, the former mainly produced a dimer, while the latter produced a ladder of bands up to a tetramer. When passed through a gel filtration column in a native state, these peptides were exclusively separated as a dimer and a tetramer, respectively. These results suggested that the internal DNA-binding and C-terminal chromo-shadow domains are both involved in heterochromatin formation in vivo.

Binding Sites↗
PubMed1999

Mutant influenza viruses with a defective NS1 protein cannot block the activation of PKR in infected cells.

A short model genome RNA and also the genome RNA of influenza A virus bearing both 5'- and 3'-terminal common sequences activated the interferon-induced double-stranded-RNA-dependent protein kinase, PKR, by stimulating autophosphorylation in vitro. The activated PKR catalyzed phosphorylation of the alpha subunit of eucaryotic translation initiation factor 2 (eIF2alpha). The NS1 protein efficiently eliminated the PKR-activating activity of these RNAs by binding to them. Two mutant NS1 proteins, each harboring a single amino acid substitution at different regions, exhibited temperature sensitivity in their RNA binding activity in the mutant virus-infected cell lysates as well as when they were prepared as fusion proteins expressed in bacteria. The virus strains carrying these mutant NS1 proteins exhibited temperature sensitivity in virus protein synthesis at the translational level, as reported previously, and could not repress the autophosphorylation of PKR developing during the virus growth, which is normally suppressed by a viral function(s). As a result, the level of eIF2alpha phosphorylation was elevated 2.5- to 3-fold. The defect in virus protein synthesis was well correlated with the level of phosphorylation of PKR and eIF2alpha.

Defective Viruses↗
PubMed1999

No changes in paired viral antibody titers during the course of acute schizophrenia.

Although there have been many studies surveying the prevalence of specific viral antibodies in a large cohort of patients with schizophrenia, changes in antibody levels during the course of acute illness have not been fully investigated. We conducted a preliminary study investigating levels of antibodies to 5 herpesviruses (herpes simplex virus type 1, cytomegalovirus, Epstein-Barr virus, varicella-zoster virus and human herpesvirus type 6) and 6 other viruses (measles, rubella, mumps, influenza A and B and Japanese encephalitis viruses) in paired sera of 8 patients with acute onset or exacerbation of schizophrenia. Assay for specific immunoglobulin M (IgM) antibody was also performed for herpesviruses and mumps. Neither any relevant change in antibody levels nor appearance of specific IgM antibody was observed for any of the viruses in any of the patients investigated. It is unlikely that the active infection or reactivation of these viruses has direct causal relationship to schizophrenia in these patients.

Acute Disease↗
PubMed1999

Schizophrenia and the HLA-DRB1 gene in the Japanese population.

OBJECTIVE: Small Japanese studies have suggested that patients with schizophrenia have higher rates of the HLA-DR1 gene than normal subjects. The authors' goal in the present study was to confirm this finding in a larger number of Japanese subjects. They also investigated the rate of DR4 in Japanese patients with schizophrenia because it has been reported that Caucasian patients with schizophrenia have higher rates of DR4. METHOD: They studied the occurrence of the HLA-DRB1 gene in 233 unrelated Japanese patients with schizophrenia compared with the occurrence of the gene in a group of 493 healthy Japanese volunteers. RESULTS: A larger proportion of the patients with schizophrenia (15.9%) than the comparison subjects (10.5%) were found to have DR1 (DRB1*0101). The proportion of patients (36.9%) and comparison subjects (40.6%) with DR4 did not differ significantly. CONCLUSIONS: Consistent with the findings of three other Japanese studies, the findings of the present study suggest that the rate of HLA-DR1 may be higher in Japanese patients with schizophrenia than in normal Japanese subjects. No evidence for an association between schizophrenia and the rate of DR4 was obtained in this study, although the combined data from the present study and other Japanese studies support the finding of lower rates of DR4 among patients with schizophrenia.

Adult↗
PubMed1998

Unusual relapse of adult T-cell leukemia/lymphoma after spontaneous remission.

A 42-year-old man was diagnosed with acute adult T-cell leukemia/lymphoma (ATL/L). Abnormal peripheral blood cells (45% of white blood cells) (Fig. 1a), hypercalcemia, and systemic lymphadenopathy were observed. Flow cytometric analysis (FCM) using peripheral mononuclear cells (PMNC) revealed that the immunophenotype of tumor cells was CD4+ CD8- CD25+ CD45RA- CD45RO+. Nevertheless, he developed a spontaneous remission 6 months later. At remission, the number of CD4-, CD25-, and CD45RO-positive cells decreased, while CD8- and CD45RA-positive cells increased to normal levels as previously reported by Suzuki et al. [1]. He was then referred to the outpatient clinic where he was periodically evaluated and received no therapy. Because of a serious sense of fullness he was re-admitted 30 months after diagnosis. Physical examination revealed ascites and small lymphadenopathy in the right axilla. Atypical lymphoid cells were not observed on microscopic examination of the blood smear. FCM using PMNC revealed that CD4+ CD25+ cells (3%) were within the normal range. Serum calcium was also within the normal range. Abdominal ultrasound examination showed massive ascites. Paracentesis demonstrated that the ascitic fluid had a high white blood cell count (3.15 x 10(9)/l) with a marked increase in abnormal large cells (Fig. 1b). FCM using mononuclear cells in the fluid revealed that 87.3% of the cells were double-positive for CD4 and CD25. Southern blot analysis of the cells confirmed monoclonal integration of human T-lymphotropic virus type 1 (HTLV-1) proviral DNA. The integrated genome was considered to be identical with that detected at initial presentation (Fig. 2). A diagnosis of relapsed ATL/L, with the same clone as was detected at initial diagnosis, was made. Although he was treated with cytotoxic drugs, he did not respond and he died of renal failure 1 month after relapse. Autopsy revealed nodular invasive lesions at the rectovesical pouch, omentum, diaphragm, and pericardium with peritoneal dissemination.

Adult↗
PubMed1998

C677T polymorphism in methylenetetrahydrofolate reductase gene and psychoses.

A common missense mutation of the methylenetetrahydrofolate reductase (MTHFR) gene (C677T) has been shown to be a risk factor for premature cardiovascular disease and neural tube defect. Deficient activity of MTHFR has also been implicated in the pathogenesis of psychiatric conditions such as schizophrenia and affective disorders. Arinami et al found an increased frequency of homozygosity for the mutated type (T677) of the MTHFR gene in schizophrenia and depression. We tried to replicate this finding in a sample of 343 patients with schizophrenia, 143 with bipolar disorder, 71 with unipolar depression, and 258 controls; however, there was no significantly increased frequency of homozygosity for the T677 allele in any of the diagnostic groups, compared to the controls. Our results suggest that homozygosity for the T677 allele of the MTHFR gene is unlikely to play a major role in the pathogenesis of schizophrenia or affective disorders in our sample.

Adult↗
PubMed1998

An assessment of local curability of endoscopic surgery in early gastric cancer without satisfaction of current therapeutic indications.

BACKGROUND AND STUDY AIMS: Therapeutic endoscopy for early gastric cancer has been established with strict criteria for indications. In the present study, we evaluated the efficacy of endoscopic treatment in cases that did not fulfil the standard therapeutic criteria, consisting of well differentiating mucosal adenocarcinomas less than 2 cm in size and without an ulcer or a scar. PATIENTS AND METHODS: Sixty nine early gastric cancers in 64 patients that did not fulfil the standard criteria were treated endoscopically, and a rate of cure was retrospectively assessed during a mean follow-up of 5.2 years. Endoscopic treatment consisted of mucosal resection or thermal methods, or both. RESULTS: Curative resection was achieved in 19/20 (95%) of cases which came into one of the following categories, all being well differentiated adenocarcinomas, less than 3.0 cm in size, without ulcer or the scar of an ulcer, with invasion limited to mucosal layer (depth m); tumors less than 2.0 cm, with an ulcer or scar, depth m; tumors less than 2.0 cm, without ulcer or scar, invading the submucosa but in which invasion was limited to the superficial portion (depth sm-1); and poorly differentiated tumors less than 1.0 cm in size, without an ulcer or scar, depth m. The rate of cure in this group was statistically similar to the cure rate of cases that fulfilled the standard criteria (98%). CONCLUSIONS: Our retrospective results suggest that the indications for curative treatment of early gastric cancer could be expanded. Prospective studies are required.

Adenocarcinoma↗
PubMed1998

Direct determination of carbon and nitrogen contents of natural bacterial assemblages in marine environments

In order to better estimate bacterial biomass in marine environments, we developed a novel technique for direct measurement of carbon and nitrogen contents of natural bacterial assemblages. Bacterial cells were separated from phytoplankton and detritus with glass fiber and membrane filters (pore size, 0.8 &mgr;m) and then concentrated by tangential flow filtration. The concentrate was used for the determination of amounts of organic carbon and nitrogen by a high-temperature catalytic oxidation method, and after it was stained with 4',6-diamidino-2-phenylindole, cell abundance was determined by epifluorescence microscopy. We found that the average contents of carbon and nitrogen for oceanic bacterial assemblages were 12.4 +/- 6.3 and 2.1 +/- 1.1 fg cell-1 (mean +/- standard deviation; n = 6), respectively. Corresponding values for coastal bacterial assemblages were 30.2 +/- 12.3 fg of C cell-1 and 5.8 +/- 1.5 fg of N cell-1 (n = 5), significantly higher than those for oceanic bacteria (two-tailed Student's t test; P < 0.03). There was no significant difference (P > 0.2) in the bacterial C:N ratio (atom atom-1) between oceanic (6.8 +/- 1.2) and coastal (5.9 +/- 1.1) assemblages. Our estimates support the previous proposition that bacteria contribute substantially to total biomass in marine environments, but they also suggest that the use of a single conversion factor for diverse marine environments can lead to large errors in assessing the role of bacteria in food webs and biogeochemical cycles. The use of a factor, 20 fg of C cell-1, which has been widely adopted in recent studies may result in the overestimation (by as much as 330%) of bacterial biomass in open oceans and in the underestimation (by as much as 40%) of bacterial biomass in coastal environments.

Journal Article↗