Biomedical subjects

N Masuda

Publications and source records attributed to N Masuda.

At least 37 records · Page 2Linked to original sources

PubMed2001

Age-dependent and tissue-specific CAG repeat instability occurs in mouse knock-in for a mutant Huntington's disease gene.

Huntington's disease (HD) is a neurodegenerative disorder characterized by the expansion of CAG repeats in exon 1 of the HD gene. To clarify the instability of expanded CAG repeats in HD patients, an HD model mouse has been generated by gene replacement with human exon 1 of the HD gene with expansion to 77 CAG repeats. Chimeric proteins composed of human mutated exon 1 and mouse huntingtin are expressed ubiquitously in brain and peripheral tissues. One or two CAG repeat expansion was found in litters from paternal transmission, whereas contraction of CAG repeat in litters was observed through maternal transmission. Elderly mice show greater CAG repeat instability than younger mice, and a unique case was observed of an expanded 97 CAG repeat mouse. Somatic CAG repeat instability is particularly pronounced in the liver, kidney, stomach, and brain but not in the cerebellum of 100-week-old mice. The same results of expanded CAG repeat instability as observed in this HD model mouse were confirmed in the human brain of HD patients. Glial fibrillary acidic protein (GFAP)-positive cells have been found to be increased in the substantia nigra (SN), globus pallidus (GP), and striatum (St) in the brains of 40-week-old affected mice, although without neuronal cell death. The CAG repeat instability and increase in GFAP-positive cells in this mouse model appear to mirror the abnormalities in HD patients. The HD model mouse may therefore have advantages for investigations of molecular mechanisms underlying instability of CAG repeats.

Age Factors↗

PubMed2001

Expression of p53 protein related to smoking and alcoholic beverage drinking habits in patients with esophageal cancers.

In esophageal squamous cell carcinoma (SCC), we used immunohistochemical analysis to further elucidate the correlation of p53 protein expression with clinicopathological factors, as well as with risk factors, such as tobacco smoking, alcohol consumption and a family history of cancer, using odds ratios (ORs). The expression of p53 protein was demonstrated in 55.1% of 89 esophageal SCC cases examined by immunohistochemistry. The expression of p53 protein did not correlate with gender, age, histological grading, lymph node metastasis, or TNM stage. The prevalence of p53 expression was significantly higher in patients with multiple primary esophageal cancers (P<0.05). p53 expression did not correlate with prognosis in univariate survival analysis. The esophageal SCC in either smokers or alcohol users was 4.67-5.83 times more likely to express p53 protein, while the likelihood of p53 expression in patients who use both tobacco and alcohol was more than 14.0 times. However, a significant association was not found between p53 expression and a family history of cancer, this having an OR as low as 1.85. The expression of p53 protein did not correlate with clinicopathological factors and prognosis in univariate and multivariate survival analyses. In contrast, tobacco smoking and alcohol consumption were shown to be strongly associated with p53 mutations in esophageal carcinogenesis.

Adult↗

PubMed2001

The genomic structure and expression of MJD, the Machado-Joseph disease gene.

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder that is clinically characterized by cerebellar ataxia and various associated symptoms. The disease is caused by an unstable expansion of the CAG repeat in the MJD gene. This gene is mapped to chromosome 14q32.1. To determine its genomic structure, we constructed a contig composed of six cosmid clones and eight bacterial artificial chromosome (BAC) clones. It spans approximately 300kb and includes MJD. We also determined the complete sequence (175,330bp) of B445M7, a human BAC clone that contains MJD. The MJD gene was found to span 48,240bp and to contain 11 exons. Northern blot analysis showed that MJD mRNA is ubiquitously expressed in human tissues, and in at least four different sizes; namely, 1.4, 1.8, 4.5, and 7.5kb. These different mRNA species probably result from differential splicing and polyadenylation, as shown by sequences of the 21 independent cDNA clones isolated after the screening of four human cDNA libraries prepared from whole brain, caudate, retina, and testis. The sequences of these latter clones relative to the MJD gene in B445M7 indicate that there are three alternative splicing sites and eight polyadenylation signals in MJD that are used to generate the differently sized transcripts.

Alternative Splicing↗

PubMed2001

Predictive value of interleukin-8 and granulocyte elastase in pulmonary complication after esophagectomy.

BACKGROUND: We investigated whether or not interleukin-8 (IL-8) and granulocyte elastase (GE) can be associated with pulmonary complication after esophagectomy (the most common cause of postoperative death). METHODS: We measured serial changes in the IL-8 concentration and GE activity in the plasma and bronchoalveolar lavage fluid (BALF) of 17 patients who had undergone esophagectomy, and examined the relationship between these mediators and postoperative pulmonary complication. RESULTS: Pulmonary complication occurred in 6 patients (35%, Pneum+ group). Plasma IL-8 increased at the end of the surgery then decreased, but there was no significant difference between the Pneum+ group and the group without pulmonary complication (11[65%], Pneum- group). IL-8 and GE in BALF were significantly higher in the Pneum+ group than in the Pneum- group on days 1 and 3 after the operation. There was a significant and positive correlation between IL-8 and GE in BALF. CONCLUSIONS: Our results indicate that IL-8 and GE in BALF may be useful for the prediction of postoperative pulmonary complication.

Aged↗

PubMed2001

Hypersusceptibility of the Pseudomonas aeruginosa nfxB mutant to beta-lactams due to reduced expression of the ampC beta-lactamase.

The Pseudomonas aeruginosa nfxB mutant lacking mexAB-oprM showed hypersusceptibility to 9 out of 24 beta-lactams tested. This hypersusceptibility was found for the nfxB mutant lacking mexAB-oprM-mexXY (N108) but not for the nfxB mutant lacking both mexAB-oprM-mexXY and ampC. The level of the AmpC beta-lactamase induction was reduced in N108. Thus, the reduced AmpC induction must be the cause of the hypersusceptibility.

Bacterial Outer Membrane Proteins↗

PubMed2001

[Antioxidative effects of fluvastatin, and its major metabolites [II]].

We investigated the antioxidative effects of fluvastatin (FV or (+/-)-FV), each enantiomer ((+)-FV, (-)-FV) and its major metabolites on lipid peroxidation using rat and human liver microsomes. The extent of NADPH induced microsomal (Ms) lipid peroxidation was determined by thiobarbituric acid (TBA) assay. The antioxidative effect of each compound was shown as the percentage of inhibition on the formation of TBA reactive substance (TBARS) against vehicle control. The antioxidative effects of alpha-tocopherol (Toc), a potent antioxidative vitamin, probucol (PR), a potent antioxidative drug, pravastatin (PV) and simvastatin (SV), HMG-CoA reductase inhibitors, were also tested. The (+/-)-FV inhibit the formation of TBARS by 40 to 70% depending on Ms concentrations. The antioxidative effects of PR and TOC were comparable to those of FV. The inhibitory effects of PV and SV on the formation of TBARS were less potent than (+/-)-FV, PR and TOC. (+)-FV, (-)-FV, and (+/-)-FV inhibited the formation of TBARS by approximately 50% using rat hepatic microsomes. The antioxidative effects of (+)-FV was comparable to that of (-)-FV using human hepatic microsomes. These results indicated that the antioxidative effects of (+)-FV were comparable to those of (-)-FV, although the HMG-CoA reductase inhibitory activity of (+)-FV was 30-fold higher than that of (-)-FV.

Animals↗

PubMed2001

Comparison of ticlopidine and cilostazol for the prevention of restenosis after percutaneous transluminal coronary angioplasty.

Prevention of restenosis after percutaneous transluminal coronary angioplasty (PTCA) continues to be a significant problem. Recent controlled studies have demonstrated that cilostazol suppresses restenosis after PTCA. The effects of ticlopidine, another antiplatelet agent, were compared in terms of outcomes of patients randomized for treatment with the two drugs after PTCA. A total of 35 patients (47 lesions) were assigned prospectively and randomly to ticlopidine (17 patients, 24 lesions) and cilostazol (18 patients, 23 lesions) groups. Minimal luminal diameter (MLD) and percentage of stenosis to reference diameter were estimated before PTCA, just after the procedure and after 4 months follow-up. All patients underwent 4 months angiographic follow-up, at the end of which MLD was 2.03+/-0.71 mm in the ticlopidine group and 2.05+/-0.68 mm in the cilostazol group (p = 0.95), and the percentage of stenosis to reference diameter was 31.4+/-16.7% and 30.0+/-17.0%, respectively (p = 0.78). The restenosis rate was 12.5% in the ticlopidine group and 17.4% in the cilostazol group (p = 0.69), relatively low as compared to the 20% to 30% reported in previous studies. Adverse drug reactions during the follow-up period were observed in two of the ticlopidine group and none of the cilostazol group. We conclude that both ticlopidine and cilostazol are effective for the prevention of restenosis after PTCA, however the former may be associated with slight side effects.

Aged↗

PubMed2001

Irinotecan in the treatment of small cell lung cancer.

Combination chemotherapy is the cornerstone of treatment of small cell lung cancer, leading to a meaningful survival benefit for these patients. However, there have been no major advances in therapy in the last decade. Therefore, more effective new treatments are necessary to improve the outcome of therapy. Irinotecan is one of the new active agents that provide hope for more effective therapies in the 21st century. A Phase III trial carried out in Japan clearly demonstrated a survival advantage of a combination of cisplatin and irinotecan over the standard regimen of cisplatin and etoposide. This review outlines the treatment results of irinotecan as a single agent as well as in combination with other cytotoxic agents.

Antineoplastic Agents, Phytogenic↗

PubMed2001

Carboplatin calculated with Chatelut's formula plus etoposide for elderly patients with small-cell lung cancer.

OBJECTIVE: This dose escalation was conducted to evaluate the applicability of Chatelut's dosing, and to determine the efficacy and toxicity of carboplatin with etoposide in previously untreated elderly patients (>70 years) with small cell lung cancer. PATIENTS AND METHODS: Seventeen patients were treated with etoposide for 3 days and carboplatin calculated dose using Chatelut's formula on day 1 intravenously. The starting doses of etoposide on days 1 to 3, and carboplatin using the area under the concentration versus time curve (AUC) were 90 mg/m2 and 4 mg/ml x min, respectively. RESULTS: The median age was 77 years (range 71 to 87). Dose-limiting toxicity (DLT) was seen at level 4 (AUC 5 mg/ml x min of carboplatin and etoposide 100 mg/m2). Hematologic toxicity was the primary DLT. Grade 4 thrombocytopenia and Grade 4 leukopenia were observed at level 4. Non-hematologic toxicity was insignificant. The overall response rate was 94%. CONCLUSION: Etoposide at 100 mg/m2 and AUC of carboplatin of 4.5 mg/ml x min as calculated using Chatelut's formula every four weeks is the recommended dose for further phase II trials for elderly patients with small cell lung cancer.

Aged↗

PubMed2001

Establishment of the standard regimen for non-small-cell lung cancer in Japan.

Preclinical data suggest that irinotecan (Camptosar, CPT-11), a novel topoisomerase I inhibitor, has exhibited promising activity in the treatment of lung cancer. In a phase II study of non-small-cell lung cancer, irinotecan demonstrated a 32% response rate. Combinations of irinotecan and cisplatin (Platinol) have also demonstrated synergistic activity against non-small-cell lung cancer. A phase I trial of irinotecan combined with cisplatin in previously untreated non-small-cell lung cancer patients showed an encouraging response rate of 54%, with irinotecan at 60 mg/m2 on days 1, 8, and 15, plus cisplatin at 80 mg/m2. In a phase II study of chemotherapy-naive patients with stage IIIB/IV non-small-cell lung cancer, irinotecan/cisplatin yielded a response rate of 52% and a mean survival time of 44 weeks. Data from a phase III trial comparing cisplatin at 80 mg/m2 on day 1 plus vindesine at 3 mg/m2 on days 1, 8, and 15 with two irinotecan-containing regimens--cisplatin at 80 mg/m2 on day 1 plus irinotecan at 60 mg/m2 on days 1, 8, and 15, and single-agent irinotecan at 100 mg/m2 on days 1, 8, and 15--have also been reported. Responses were observed in 32%, 44%, and 21% of patients for the vindesine/cisplatin, irinotecan/cisplatin, and irinotecan arms, respectively, with corresponding median survival times of 45.6, 50.0, and 46.0 weeks; there were no significant differences in response rate or survival between treatment groups for all patients. However, subset analysis of stage IV patients indicated a significant survival advantage for irinotecan/cisplatin; the median survival time was 50 weeks for patients receiving irinotecan/cisplatin, 36.4 weeks for vindesine/cisplatin, and 42.1 weeks for irinotecan (P = .004 for the irinotecan/cisplatin arm vs vindesine/cisplatin; P = .018 for irinotecan vs vindesine/cisplatin). Another phase III study compared irinotecan/cisplatin and vindesine/cisplatin. There was no difference in overall median survival time, and the median survival times were not significantly different for stage IV patients in the respective irinotecan/cisplatin and vindesine/cisplatin arms (44.7 vs 45.3 weeks). Further studies are needed to determine whether irinotecan/cisplatin combinations improve survival in comparison with other promising platinum-containing regimens.

Adult↗

PubMed2001

[Management of axillary and internal mammary lymph nodes in primary breast cancer].

Axillary lymph node dissection (ALND) is an effective staging procedure and is essential for local control of breast cancer. The regimen of the adjuvant systemic therapy is largely based on the number of nodes involved. There is as yet no evidence of survival benefit from axillary treatment by either surgery or radiotherapy, but this issue remains controversial. In general, the standard treatment of the axilla is surgical clearance of nodes from level I and II (partial ALND). If these nodes are involved, the clearance of level III nodes (complete ALND) is indispensable from the viewpoint of local control. Because a high rate of adverse events is observed, the extent of ALND should be determined by considering the balance between side effects and therapeutic benefit on a case-by-case basis. For the management of internal mammary nodes, most reports on randomized trials indicate that neither surgical treatment nor radiotherapy influences survival. However, the prognostic significance of internal mammary node status is high and a selected biopsy of lymph nodes with adenopathy should be considered for staging purposes. The significance of local control in this region is still controversial at present. About 30% to 40% of all invasive breast cancers are node positive. Thus, in most cases, the potential morbidity of ALND could be avoided if the status of the axillary nodes was ascertained with a less invasive procedure. The technique of sentinel lymph node biopsy may eventually prove to decrease the need for standard ALND. The randomized trial NSABP-B32 is ongoing and the results should indicate the clinical need for ALND.

Axilla↗

PubMed2001

[The significance of neoadjuvant intra-arterial chemotherapy for locally advanced breast cancer by different methods].

For neoadjuvant intra-arterial (IA) chemotherapy in locally advanced breast cancer patients, Seldinger's methods were found to be convenient and had the same effect and outcome as conventional methods. The prognosis of the patients in whom IA chemotherapy was locally effective and had fewer than n 1 lymph node metastases was comparatively favorable. However, several patients who underwent IA chemotherapy later experienced local recurrence, and the cause of these patient's death was distant metastases in almost all cases. We recommend neoadjuvant IA and systemic chemotherapy, and systemic adjuvant chemotherapy.

Adult↗

PubMed2001

[A case of locally advanced breast cancer successfully treated with wide resection and reconstruction of chest wall with A-O metallic plates].

A 63-year-old female with locally advanced breast cancer was treated with preoperative chemotherapy using docetaxel. The therapeutic regimen was comprised of four cycles at 3-week intervals. One cycle consisted of 80 mg of docetaxel which was administered on day 1. A remarkable response was confirmed. The side effects such as leukopenia, general fatigue and alopecia were moderate and had no influence on the patient's QOL. After preoperative chemotherapy, a full thickness chest wall resection was performed. Chest wall defect was reconstructed with orthopedic A-O metallic plates, Marlex mesh and rectus abdominis myocutaneous flap. These metal plates were very useful because it was easy to bend and twist them manually to fit the defect at the time of operation. Moreover, the curved metal plates preserved the cone form of the chest cage. The postoperative course was favourable without frail chest or wound infection.

Antineoplastic Agents, Phytogenic↗

PubMed2000

Mutation and expression of the metastasis suppressor gene KAI1 in esophageal squamous cell carcinoma.

BACKGROUND: KAI1/CD82, a tumor metastasis suppressor gene, is correlated inversely with the progression and invasion of several tumors. It also has been reported that the KAI1 gene is related to the tumor suppressor gene p53. This study was performed to clarify the correlation between KAI1/CD82 expression and clinicopathologic characteristics and p53 expression in patients with esophageal squamous cell carcinoma (ESCC). The authors also investigated mutation of the KAI1 gene coding region to determine whether this may reduce KAI1 expression in ESCC. METHODS: Using immunohistochemistry with anti-KAI1 polyclonal antibody and monoclonal antibody against p53, KAI1/CD82 and p53 expression were detected in 55 patients with ESCC who had undergone surgery. The authors examined the KAI1 gene mutation in 22 patients with ESCC by polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis and DNA sequencing. RESULTS: KAI1/CD82 expression was positive in 36 of 55 patients (65.5%). There was a significant inverse correlation between KAI1/CD82 expression and regional lymph node metastasis (P = 0.0045), distant metastasis (P = 0.0092), the number of lymph node metastases (P = 0.0019), and pathologic stage (P = 0.0046). The survival rates of KAI1/CD82 negative patients were poorer than those of positive patients (P = 0. 024). The correlation between KAI1 positive and p53 positive tumors was not statistically significant. None of the 22 patients with ESCC showed mutation of the KAI1 gene by PCR-SSCP. In one patient, there was polymorphism in the SSCP assay and DNA sequencing. CONCLUSIONS: The authors demonstrated immunohistochemically that the expression of KAI1 protein appeared to be correlated with lymph node metastasis. Mutation does not seem to be a mechanism for dysregulation of the KAI1 protein in ESCC.

Adult↗

PubMed2000

Nitrotyrosine in esophageal squamous cell carcinoma and relevance to p53 expression.

We have examined the expression of nitrotyrosine, a marker of peroxynitrite formation, in 55 esophageal cancers by immunohistochemistry. Nitrotyrosine was detected in 21 of 55 (38.2%) esophageal cancers. Comparison of nitrotyrosine expression and the pathological findings showed that there was a significant association between the expression of nitrotyrosine and each of the depth of tumor invasion (P<0.01), occurrence of metastasis (P<0.05), pathological stage (P<0.01), smoking status (P<0.05) and alcohol intake (P<0.05). The survival rate of patients with nitrotyrosine-negative cancer was significantly higher than that of patients with nitrotyrosine-positive cancer (log-rank test, P<0.01). p53 was detected in 29 of 55 (52.7%) esophageal cancers, however, p53 expression did not correlate with nitrotyrosine expression. In conclusion, nitrotyrosine, a product of nitrogen species, is expressed in esophageal squamous cell carcinoma, which suggests that exogenous risk factors, such as tobacco and alcohol, through NO, are associated with carcinogenesis and progression of esophageal squamous cell carcinoma.

Adult↗

PubMed2000

Nuclear receptor binding factor-2 (NRBF-2), a possible gene activator protein interacting with nuclear hormone receptors.

A protein named nuclear receptor binding factor-2 (NRBF-2) was identified by yeast two-hybrid screening, as an interaction partner of peroxisome proliferator-activated receptor alpha as well as several other nuclear receptors. NRBF-2 exhibited a gene activation function, when tethered to a heterologous DNA binding domain, in both mammalian cells and yeast.

Amino Acid Sequence↗

PubMed2000

Cloning and expression study of the mouse tetrodotoxin-resistant voltage-gated sodium channel alpha subunit NaT/Scn11a.

We have cloned a tetrodotoxin-resistant (TTX-R) voltage-gated sodium channel alpha subunit from a mouse cDNA library and designated it as NaT. It encodes 1765 amino acid residues and is virtually identical to that of Scn11a, which has been reported recently, except for 40 nt and 14 aa substitutions. The amino acid identity of NaT/Scn11a with rat NaN/SNS2 is 88%. NaT/Scn11a was mapped to mouse chromosome 9F3-F4 by fluorescence in situ hybridization (FISH). While rat NaN/SNS2 has been reported to be expressed specifically in the peripheral sensory neurons, NaT/Scn11a is expressed not only in the peripheral sensory neurons but also in the spinal cord, uterus, testis, ovary, placenta, and small intestine. NaT is detectable in mouse embryos 15 days postcoitus (p.c.), around the phase of organogenesis and gonadal differentiation. These findings demonstrate a unique distribution of NaT/Scn11a and suggest some of its roles in the above-mentioned processes.

Amino Acid Sequence↗

PubMed2000

Identification of a novel human voltage-gated sodium channel alpha subunit gene, SCN12A.

We have cloned a cDNA encoding a novel human voltage-gated sodium channel alpha subunit gene, SCN12A, from human brain. Two alternative splicing variants for SCN12A have been identified. The longest open reading frame of SCN12A encodes 1791 amino acid residues. The deduced amino acid sequence of SCN12A shows 37-73% similarity with various other mammalian sodium channels. The presence of a serine residue (S360) in the SS2 segment of domain I suggests that SCN12A is resistant to tetrodotoxin (TTX), as in the cases of rat Scn10a (rPN3/SNS) and rat Scn11a (NaN/SNS2). SCN12A is expressed predominantly in olfactory bulb, hippocampus, cerebellar cortex, spinal cord, spleen, small intestine, and placenta. Although expression level could not be determined, SCN12A is also expressed in dorsal root ganglia (DRG). Both neurons and glial cells express SCN12A. SCN12A maps to human chromosome 3p23-p21.3. These results suggest that SCN12A is a tetrodotoxin-resistant (TTX-R) sodium channel expressed in the central nervous system and nonneural tissues.

Amino Acid Sequence↗