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Atsushi Sato

Publications and source records attributed to Atsushi Sato.

At least 19 recordsLinked to original sources
PubMed2003

A peptide mimetic of human interferon (IFN)-beta.

Type I interferons (IFNs) are cytokines that are used clinically as antiviral and antitumour agents. The interaction of IFNs with their heterodimeric type I IFN receptor comprised of IFNAR1 and IFNAR2 is a first step to inducing biological actions. Here, we describe the successful mimicry of IFN-beta by a peptide isolated by phage-display screening using a neutralizing anti-IFN-beta monoclonal antibody. The 15-mer peptide, designated SYR6, was shown to compete with IFN-beta for binding to type I IFN receptor in a concentration-dependent manner, and was shown to elicit antiviral activity on cultured cells. This antiviral activity was not eliminated in the presence of neutralizing monoclonal antibodies to IFN-alpha, -beta and -gamma, and a low concentration of soluble type I IFN receptor, suggesting that it was not due to IFN contamination or the induction of endogenous IFNs by SYR6. This peptide might be a potent agonist to provide a mechanism of activating heterodimeric cytokine receptors.

Amino Acid Sequence↗
PubMed2003

Holographic edge-illuminated polymer Bragg gratings for dense wavelength division optical filters at 1550 nm.

We discuss the use of holographic photopolymer materials for use as dense wavelength division multiplexing filters in the C-band of the optical communication spectrum. An edge-illuminated hologram configuration is described that effectively extends the grating length to achieve narrow band filters operating near 1550 nm in photopolymers that are 100-200-microm thick. This configuration enables the formation of apodized and cascaded filter systems. Rouard's method is used to examine the properties of both apodization and cascaded gratings and indicates the potential for narrow spectral bandwidths (< 0.2 nm) and high side-lobe suppression (<-- 30 dB). Initial experimental results with a commercially available photopolymer are provided that verify narrowband spectral-transmittance properties (< 0.6 nm) and the ability to apodize the index profile. The primary limitation of the design is the absorption of existing photopolymer materials. Optimizing the polymer chemistry for filter design at 1550 nm may solve this problem.

Journal Article↗
PubMed2003

Expression of copper-transporting P-type adenosine triphosphatase (ATP7B) as a chemoresistance marker in human oral squamous cell carcinoma treated with cisplatin.

An important clinical problem in the treatment of oral squamous cell carcinoma is the intrinsic/acquired resistance to cisplatin-based chemotherapy. Copper-transporting P-type adenosine triphosphate (ATP7B) has been reported to be associated with cisplatin resistance in vitro (Komatsu et al., Cancer Res 60, 1312-1316,2000). However, the clinical significance of this transporter has not previously been addressed. Our aim of this study was to investigate if ATP7B is expressed in oral squamous cell carcinoma and whether its expression correlates with prognosis and reduced responsiveness to cisplatin treatment. Biopsy tissues were obtained from the tumors of 70 patients with oral SCC, and 51 patients received cisplatin-based preoperative chemotherapy. We performed immunohistochemical analysis of ATP7B using monoclonal antibody against ATP7B in 51 oral SCC and adjacent neoplastic tissues. The significance of ATP7B in the prognosis of patients with oral SCC was also examined in the survival analysis of mortality follow-up data covering the period 1991 through 2000. We retrospectively examined the expression of ATP7B in primary oral SCC carcinoma and its association with chemotherapeutic effect. A variable degree of cytoplasmic staining of tumor cells was observed in 54.9% (28/51 cases) of the analyzed carcinomas. Patients with ATP7B-positive tumors had a significantly inferior response to chemotherapy compared with the patients with ATP7B-negative tumors (P = 0.03). The patients who received cisplatin-based chemotherapy with ATP7B-positive carcinomas had a significantly poorer overall survival than those with ATP7B-negative tumors (P = 0.015). These findings suggest that high levels of ATP7B expression in oral SCC are associated with unfavorable clinical outcome in patients with oral SCCs treated with cisplatin-based chemotherapy. ATP7B expression may be a preoperative indicator for a choice of cisplatin in some patients.

Adenosine Triphosphatases↗
PubMed2003

"Real" three-dimensional constructive interference in steady-state imaging to discern microneurosurgical anatomy. Technical note.

Three-dimensional (3D) neuroimages are generally considered useful for neurosurgical practice. Nevertheless, neuroimaging modalities such as 3D digital subtraction angiography and 3D computerized tomography angiography are still insufficient because the resulting images fail to delineate neural structures. Complex neurosurgical procedures are mostly performed in the cerebrospinal fluid (CSF) space of the basal cistern, where vessels and neural structures are present along with the lesion. The magnetic resonance (MR) imaging-derived 3D constructive interference in steady-state (CISS) imaging displays the margin between the CSF and neural structures, vessels, and dura mater in detail, in a two-dimensional fashion. The authors know that volume-rendered 3D CISS images would be more useful for surgery than conventional ones. Although the usefulness of "virtual MR image endoscopy" was reported previously, the endoscopic view is different from the operative field because of the perspective being emphasized. Therefore, to simulate surgical views, the authors made 3D neuroimages from a 3D CISS MR sequence by using an advanced computer workstation. After generating volume images, a cutting method was used in the desired plane to visualize the lesion with reference to a multiplanar reformatted image. The authors call these "real" 3D CISS images, and they are more comparable to the operative field. This newly developed method of producing a real 3D CISS image was used in 30 cases and contributed to the understanding of the relationship between a lesion and surrounding structures before attempting neurosurgical procedures, with minimal invasiveness to the patient.

Basilar Artery↗
PubMed2003

Clinical and neuroimaging characteristics of hydrocephalus associated with vestibular schwannoma.

OBJECT: The clinical and neuroimaging characteristics of hydrocephalus associated with vestibular schwannoma were retrospectively analyzed to improve the perioperative management of the circulation of cerebrospinal fluid. METHODS: A retrospective analysis was performed in 236 patients with unilateral vestibular schwannomas. The patients' ages ranged from 17 to 83 years (mean 53.6 +/- 13.2 years), and the diameters of the tumors the patients harbored ranged from 5 to 60 mm (mean 30.5 +/- 12.7 mm). Hydrocephalus was present before tumor resection in 33 patients (14%) and in six of these patients focal dilation of the sylvian fissures was noted. There was a significant correlation between the incidence of hydrocephalus and tumor size. The incidence of preoperative hydrocephalus among elderly patients (> or = 65 years of age) was 28.6% and that among younger patients (< 65 years of age) was 10.8%. Tumors in elderly patients with hydrocephalus (mean tumor diameter 32.8 +/- 11.7 mm; 12 patients) were significantly smaller than those in younger patients (mean tumor diameter 41.7 +/- 10.9 mm; 21 patients). Among patients with tumors smaller than 30 mm (114 patients), the incidence of hydrocephalus in elderly patients (25%) was 12-fold higher than that in younger patients (2.1%). Six patients with hydrocephalus who had focal dilation of the sylvian fissures were significantly older than 27 patients with hydrocephalus in whom there was no focal dilation. The dilated sylvian fissures collapsed in two patients spontaneously after tumor resection and in the other four patients after shunt placement. CONCLUSIONS: The incidence of associated hydrocephalus is higher in older patients. Communicating hydrocephalus tends to occur in elderly patients. Enlargement of the ventricles with focal dilation of the sylvian fissures should not be misinterpreted as physiological brain atrophy.

Adolescent↗
PubMed2003

A highly sensitive detection method for somatic mutations in p53 gene.

A simple and highly sensitive detection method for somatic mutations, which is applicable to diagnostic samples is developed. This method detects somatic mutations that are lower than several percent in abundance. The unique feature with this method is that single-nucleotide primer extension is carried out in the absence of dye terminators that carry respective bases in the wild type gene. Data of mutation sites and bases in the target genes are obtained from databases. Primers of different nucleotide length are designed so that electrophoreses of the single-nucleotide primer extension products allow identification of respective mutations. Based on somatic mutation data in IARC TP53 mutation database, this method was applied to p53 somatic mutations. Results showed that extension reactions in 5 separate tubes allowed detection of mutations in human p53 gene for the most frequent 12 mutations in a nucleotide sequence of 14,049-14,522, which cover hot spot regions in exons 7 and 8. Confirming these results, reported mutations of p53 in human culture cells, MiaPaCa2, TE-6, RPMI8226, DLD1, and PC-3 are detected at 5% relative abundance in the sample DNA.

DNA Mutational Analysis↗
PubMed2003

[Mucositis].

Mucositis is a significant dose-limiting factor associated with cancer chemotherapy and radiotherapy. For exact management, an early diagnosis and precise evaluation are surely required. A basis of the prevention and care of stomatitis is maintaining cleanliness and moisture in the mouth. The medical treatment plans of oral mucositis are a measure against infection, and prevention against symptoms, and are restoration of a tissue damage, and treatment to sharp pain. However, there is no still established prevention method. As for the present condition, in the clinical practice, there are many portions depending on experiential knowledge. In this paper, it outlined including Empiric therapy about measures of oral mucositis.

Antineoplastic Agents↗
PubMed2003

[Hypersensitivity reactions to cancer chemotherapeutic agents].

Although hypersensitivity reactions to the anticancer drug are rare, since the reactions occasionally are clinical problems enough, that measure is important. The backgrounds (the etiologic mechanisms, the frequency, and etc) differ by each, therefore the knowledge for each medicine is required for measures including prediction and the prevention. This paper reviews the sensitivity reactions of various anticancer drugs (especially, paclitaxel, cisplatin and carboplatin) also including the molecular targeting drugs (trastuzumab, rituximab).

Antibodies, Monoclonal↗
PubMed2002

Mechanism of thrombin-induced vasodilation in human coronary arterioles.

Thrombin (Thromb), activated as part of the clotting cascade, dilates conduit arteries through an endothelial pertussis toxin (PTX)-sensitive G-protein receptor and releases nitric oxide (NO). Thromb also acts on downstream microvessels. Therefore, we examined whether Thromb dilates human coronary arterioles (HCA). HCA from right atrial appendages were constricted by 30-50% with endothelin-1. Dilation to Thromb (10(-4)-1 U/ml) was assessed before and after inhibitors with videomicroscopy. There was no tachyphylaxis to Thromb dilation (maximum dilation = 87.0%, ED(50) = 1.49 x 10(-2)). Dilation to Thromb was abolished with either hirudin or denudation but was not affected by PTX. Neither N(omega)-nitro-l-arginine methyl ester (n = 7), indomethacin (n = 9), (1)H-[1,2,4] oxadiazolo-[4,3-a]quinoxalin-1-one (n = 6), tetraethylammonium chloride (n = 5), nor iberiotoxin (n = 4) reduced dilation to Thromb. However, KCl (maximum dilation = 89 +/- 5 vs. 20 +/- 10%; P < 0.05; n = 7), tetrabutylammonium chloride (maximum dilation = 79 +/- 7 vs. 21 +/- 4%; P < 0.05; n = 5), and charybdotoxin (maximum dilation = 89 +/- 4 vs. 10 +/- 2%; P < 0.05; n = 4) attenuated dilation to Thromb. In contrast to animal models, Thromb-induced dilation in human arterioles is independent of G(i)-protein activation and NO release. However, Thromb dilation is endothelium dependent, is maintained on consecutive applications, and involves activation of K(+) channels. We speculate that an endothelium-derived hyperpolarizing factor contributes to Thromb-induced dilation in HCA.

Adult↗
PubMed2002

Decreased expression of DFF45/ICAD is correlated with a poor prognosis in patients with esophageal carcinoma.

BACKGROUND: DNA fragmentation factor 45 (DFF45)/inhibotor of caspase activated DNAse (ICAD) forms a complex with DFF40/CAD and inhibits its DNA cleaving function during apoptosis. DFF45 also functions as a chaperone for native DFF40 and is necessary for its function. It has been indicated that defects in the apoptotic pathway may exist in neoplastic cells. METHODS: The authors investigated mRNA expression of DFF45 in a series of 46 esophageal squamous cell carcinoma (ESCC) specimens using polymerase chain reaction amplification. The results were correlated with the patients' clinicopathologic characteristics. RESULTS: DFF45 mRNA expression was significantly lower in tumors with higher pathologic stage, higher tumor status (T status), lymph node metastasis, or more extensive lymphatic invasion. Patients who had low DFF45 mRNA expression (indicated by the ratio of DFF45 mRNA expression in tumor to DFF45 mRNA expression in normal esophageal mucosa [tumor:normal] < 1) had a significantly shorter survival after undergoing surgery compared with patients who had high DFF45 mRNA expression (tumor:normal > 1, P = 0.0006; log-rank test, P = 0.0003; median follow-up, 14.6 months). CONCLUSIONS: Patients with ESCC with decreased DFF45 mRNA expression levels had a poor prognosis compared with patients who had high DFF45 mRNA expression levels.

Aged↗
PubMed2002

Uridine phosphorylase is a potential prognostic factor in patients with oral squamous cell carcinoma.

BACKGROUND: Uridine phosphorylase (UPase) catalyzes the reversible phosphorolysis of uridine to uracil. The expression levels and the enzymatic activity of UPase are reported to be higher in human solid tumors than in adjacent normal tissues. However, to the authors' knowledge the clinical significance of UPase expression as determined by immunohistochemical analysis has not been demonstrated in human malignancies. METHODS: The authors prepared the antibody against UPase, examined the staining of UPase in 72 cases of oral squamous cell carcinoma (SCC) with immunohistochemical analysis using the antibody, and analyzed its relation to clinical and pathologic factors. RESULTS: UPase stained mainly within the invasive edges of tumors and macrophages. UPase-positive staining was observed in 56 of the 72 tumors (77.8%). High staining of UPase (defined as > 50% of cells in a tumor biopsy that are positive for UPase) in primary tumors frequently was associated with the presence of metastasis to lymph nodes (P = 0.007 by the Fischer exact test) and with lower overall survival (P = 0.03 by the log-rank test). CONCLUSIONS: The high rate of UPase staining in biopsies from patients with oral SCC may be a prognostic marker for these individuals.

Adult↗
PubMed2002

Interactions of sildenafil with various coronary vasodilators in isolated porcine coronary artery.

There are reports of serious hypotension or circulatory shock when sildenafil citrate, a selective cyclic nucleotide phosphodiesterase type 5 inhibitor, which was developed for the treatment of erectile dysfunction, is given to patients taking certain coronary vasodilators. We thus examined the interaction of sildenafil with various coronary vasodilators including nitric oxide (NO) donors in isolated porcine coronary artery. Sildenafil caused concentration-dependent relaxations of the artery precontracted with U46619 (9,11-dideoxy-9 alpha,11 alpha-methanoepoxy-prostaglandin F(2alpha)). Incubation with the NO synthase inhibitor NG-nitro-L-arginine or the soluble guanylate cyclase inhibitor ODQ (1H-[1,2,4]oxadiazolo[4,3-alpha]quinoxalin-1-one) significantly shifted the concentration-response curve for sildenafil to the right without affecting the maximum response, indicating that some part of the relaxant response to sildenafil may be the result of the inhibition of phosphodiestrase type 5-induced degradation of cyclic GMP (cGMP) that is produced through guanylate cyclase activation by NO released spontaneously. The relaxant effects of the vasodilators with an NO donor property, isosorbide dinitrate, sodium nitroprusside, nicorandil and nipradilol, were significantly enhanced by sildenafil, as shown by a significant leftward shift of their concentration-response curves. In contrast, the relaxant responses to the drugs without a property as an NO donor, diltiazem, celiprolol and pinacidil, were not affected by sildenafil. The cGMP level of the tissue was elevated after adding sildenafil, and the cGMP-generating effect of a combination of sildenafil and sodium nitroprusside was higher than that of each drug alone. The cyclic AMP level determined simultaneously was not changed by sildenafil. These results suggest that sildenafil potentiates specifically the relaxant responses of porcine coronary artery to the drugs which behave as an NO donor, providing basic evidence that the benefit of sildenafil in the treatment of erectile dysfunction can be limited by a risk of marked vasodilation when used together with NO-related coronary vasodilators.

Animals↗
PubMed2002

Telomerase activity in esophageal squamous cell carcinoma: down-regulation by chemotherapeutic agent.

BACKGROUND AND OBJECTIVES: Telomerase has been suggested as being necessary for continued cell growth and progression of cancer. Esophageal cancer and matched normal esophageal tissue from 54 patients were analyzed for telomerase activity, human telomerase reverse transcriptase (hTERT) mRNA expression, and their correlation with clinicopathological factors. METHODS: Telomeric repeat amplification protocol was used for detection of telomerase activity and real time quantitative RT-PCR was used for hTERT mRNA. An esophageal carcinoma cell line was used to study the effect of chemotherapeutic agent on telomerase. RESULTS: Telomerase activity was detectable in 79.6% of the tumor and 59.3% of the normal esophageal tissue. The level of telomerase activity in the tumor was significantly higher than that in the normal tissue. A significantly higher telomerase activity was observed in tumors with extensive blood vessel invasion. A significantly lower telomerase activity was observed in tumors that showed good response to preoperative chemotherapy than those with poor response. TE-9 cells exposed to 5-FU showed a diminished telomerase activity preceded by a time-dependent decrease in the mRNA expression of hTERT. CONCLUSIONS: Telomerase activity was high in esophageal cancer tissue and showed positive correlation with blood vessel invasion. Chemotherapeutic agents may down-regulate telomerase activity.

Aged↗
PubMed2002

Role of matrix metalloproteinase-9 in in vitro invasion of esophageal carcinoma cells.

BACKGROUND AND OBJECTIVES: Although some investigators recently suggested that MMP-9 may play a critical role in invasion and metastasis, along with MMP-2, in esophageal carcinoma, there has been no direct evidence that MMPs play a critical role in the actual invasion of esophageal carcinoma cells. Here, we investigated the role of MMPs in the in vitro invasion of esophageal carcinoma cell lines (TE-series). METHODS: Our methods included in vitro invasion assay, gelatin zymography, and enzyme-linked immunosorbent assay (ELISA). RESULTS: Four cell lines (but not TE-5) secreted MMP-2 and MMP-9 in the culture medium. Using a quantitative in vitro invasion assay, we found a significant (P = 0.002) correlation between the extent of in vitro invasion and the amount of MMP-9, but not of MMP-2, secreted into the conditioned medium in the four cell lines. In these cell lines, R-94138, a specific MMP-9 inhibitor, inhibited in vitro invasion in a dose-dependent manner. Although TE-5 did not secrete MMP-2 or MMP-9, the cells showed a strong in vitro invasion. CONCLUSIONS: Our data suggest that most of the esophageal carcinoma cell lines use MMP-9 for in vitro invasion, but others may use proteinase(s) other than MMP-9.

Carcinoma, Squamous Cell↗
PubMed2002

Distribution and variation of bacitracin synthetase gene sequences in laboratory stock strains of Bacillus licheniformis.

Distribution and variation of bacitracin synthetase gene (bac) sequences in 22 laboratory stock strains of Bacillus licheniformis were studied by Southern hybridization of bac gene probes from B. licheniformis ATCC 10716 to genomic PstI or HindIII restriction fragments. Eleven strains gave hybridization signals. These hybridization patterns were classed into two types. Eight strains showed similar patterns to that of ATCC 10716 and all, except one, produced bacitracin. The three strains showed fairly different hybridization patterns from that of ATCC 10716, and one (ATCC 33632) of them produced bacitracin. None of the remaining 11 strains, including ATCC 14580 (type strain), gave any hybridization signals. All strains carrying bac gene sequences were erythromycin resistant. With one exception, all strains without bac gene sequences were erythromycin sensitive. These results show that B. licheniformis strains are divided into two groups with respect to presence of bac gene sequences and erythromycin resistance.

Anti-Bacterial Agents↗
PubMed2002

The effectiveness of palliative resection for advanced esophageal carcinoma: analysis of 24 consecutive cases.

PURPOSE: In some patients who already have advanced esophageal cancer at the time of presentation, symptoms like the inability to eat, and complications such as bronchoesophageal fistula are so debilitating that palliative resection may be beneficial. However, resection of the esophagus is associated with significant risk, and whether this operation should be performed for palliation remains controversial. Because few reports have been published on this subject, we retrospectively analyzed 24 patients with esophageal cancer who underwent palliative resection. METHODS: Esophageal resection was performed with palliative intent in 12 patients and with curative intent in another 12 who were left with residual cancer. RESULTS: There was no operative death. All of the ten patients who had been unable to eat preoperatively were able to eat after the operation, and four patients with a life-threatening bronchoesophageal fistula were free of symptoms after the operation. Two patients died in hospital during the postoperative chemotherapy but the other 22 were discharged. The mean survival period was 264 days. CONCLUSIONS: With improved postoperative care, the risk of palliative esophageal resection is no longer considered unacceptable.

Adult↗
PubMed2002

Effectiveness of doxifluridine (5'-DFUR)/docetaxel against advanced/recurrent gastric cancer showing resistance to various anticancer drug regimens.

A 58-year-old man was diagnosed as having type 3 gastric cancer (poorly differentiated adenocarcinoma). He underwent total gastrectomy with splenectomy, as well as D3 dissection, and received postoperative chemotherapy combining oral uracil and futrafur (UFT) with cisplatin (CDDP), but results showed recurrence of multiple abdominal lymph node metastases around the aorta. He therefore received various anticancer drug regimens (irinotecan [CPT-11]/CDDP; 1 M tegafur-0.4 M gimeracil-1 M oteracil potassium [TS-1], methotrexate (MTX)/5-fluorouracil); however, final results showed growth of lymph node metastasis and simultaneous worsening of his general condition. The patient then received combined administration of doxifluridine (5'-DFUR)/docetaxel (5'-DFUR, 1000 mg/body [666.7 mg/m(2)], given by consecutive daily administration, orally, for days 1-14; and docetaxel, 80 mg/body [60 mg/m(2)], on day 8, by venous drip, every 3 weeks). Three courses of this regimen resulted in approximately 90% reduction of the abdominal lymph node size, disappearance of the right cervical lymph node metastasis, reductions of the levels of two tumor markers (carcinoembryonic antigen [CEA] and carbohydrate antigen [CA]19-9), and improvement of his general condition. In total, seven courses of the regimen were carried out. The patient died on day 298 after starting this combined regimen and showed a response period of 126 days. The primary toxicity identified was neutropenia (grade 4), as well as other low-grade (grade 1, 2) hematological and nonhematological toxicities. In the field of gastric cancer treatment, especially for patients showing multiple resistance to anticancer drugs, an effective therapy is critically needed.

Adenocarcinoma↗