Biomedical subjects

N Tanaka

Publications and source records attributed to N Tanaka.

At least 163 records · Page 9Linked to original sources

PubMed2001

The effects of stimulating protease-activated receptor-1 and -2 in A172 human glioblastoma.

Human glioblastoma cell line A172 expressed protease-activated receptor-1 and -2 (PAR-1 and PAR-2). We investigated the effects of the stimulation of these receptors by receptor-activating agonist peptides on the Ca2+ signaling, protein kinase C translocation, cell morphology and cell proliferation in A172. Both PAR-1 agonist SFLLRN and PAR-2 agonist SLIGKV induced an increase in [Ca2+]i. The prior treatment of A172 with PAR-2 agonist SLIGKV did not influence the [Ca2+]i response to PAR-1 agonist SFLLRN or thrombin, however, the prior treatment with PAR-1 agonist SFLLRN or thrombin completely abolished the second response to PAR-2 agonist SLIGKV. Treatment with each agonist peptide produced thinner and fewer processes in A172. The PAR-2 agonist inhibited the proliferation of A172 significantly while PAR-1 agonist did not. PKC-alpha and gamma were translocated from cytosol to membrane with either PAR-1 or PAR-2 stimulation, however, L was specifically translocated with SFLLRN, and lambda with SLIGKV, respectively. These results indicated that PAR-1 and PAR-2 stimulation produced a similar [Ca2+]i response and morphological changes in A172 glioblastoma while the effects on the cell proliferation and activation of PKC isozymes were distinct, suggesting that different signal transduction pathways were activated by these receptors. The uni-directional cross desensitization implies a functional linkage between PAR-1 and PAR-2 receptors.

Blotting, Western↗

PubMed2001

Malignant melanoma in the oral region: ultrastructural and immunohistochemical studies.

Malignant melanoma in the oral region is reviewed in its clinicopathological aspects. Clinically the melanomas were classified into five types; however, there were no histopathological differences according to these clinical types. Electron microscopic observation of the melanomas and primary culture cells derived from oral malignant melanoma revealed that, in patients whose prognoses were relatively good, many mature-stage melanosomes were found. Immunohistologically, there was a positive reaction for transferrin receptor and the expression of pRb2/p130 was found in only 2 of 13 patients, who are still alive after periods of over 14 years. The radiosensitivity of a cell line derived from human oral malignant melanoma was greater than that in cell lines derived from human cutaneous melanoma and with radiation, the number of melanosomes increased. There are very few clinical cases of oral malignant melanoma and very few cell lines derived from oral malignant melanoma, and so findings in these patients and these cell lines should be accumulated in order to clarify the biological behavior of oral malignant melanoma.

Cell Line↗

PubMed2001

Diagnostic accuracy of intraoperative imprint cytology in ovarian epithelial tumors.

OBJECTIVE: To evaluate imprint cytology (IC) as the intraoperative pathological consultations for ovarian epithelial tumors (OET). METHOD: We reviewed ICs obtained from 354 consecutive surgical specimens of OET. Cytological specimens were classified into five categories. Final pathological diagnoses were made according to the WHO classification. We performed logistic regression analysis, calculated the limits among benign, borderline, and malignant lesions, and analyzed the diagnostic accuracy. We also made receiver operating characteristic (ROC) curves regarding IC. RESULTS: The accuracies to differentiate benign and malignant lesions were 87.1 and 83.6%, respectively. In contrast, that of borderline lesions was 30.0%. The areas under ROC curves to diagnose benign, and malignant lesions were 0.888 (P<0.05) and 0.951 (P<0.05), respectively, that meant IC was significantly useful for diagnosis of malignancy. CONCLUSIONS: IC applied to OET was proved to be practically useful in establishing an intraoperative diagnosis by ROC curves.

Adult↗

PubMed2001

An ellagic compound and iridoids from Cornus capitata root cultures.

An ellagic acid derivative, 3,3'-di-O-methylellagic acid 4-(5"-acetyl)-alpha-L-arabinofuranoside, and two iridoid glucosides, 6alpha-dihydrocornic acid and 6beta-dihydrocornic acid, were isolated from Cornus capitata adventitious roots cultured in Murashige-Skoog (Murashige, T., Skoog, F., 1962. A revised medium for rapid growth and bioassays with tobacco tissue cultures. Physiol. Plant. 15, 473-487) liquid medium containing 10 microM CuSO(4). Three known related metabolites, i.e. stenophyllin H1, dihydrocornin and cornin were also produced in the root cultures. The chemical structures were characterized by analysis of spectroscopic data.

Ellagic Acid↗

PubMed2001

Beta(3)-adrenoceptor agonists for the treatment of frequent urination and urinary incontinence: 2-[4-(2-[[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-1-methylethyl]amino]ethyl)phenoxy]-2-methylpropionic acid.

In a search for novel analogues of beta(3)-adrenoceptor (AR) agonists relaxing the bladder for treatment of urinary dysfunction, 2-[4-(2-[[(1S,2R)-2-hydroxy-2-(4-hydroxyphenyl)-1-methylethyl]amino]ethyl)phenoxy]-2-methylpropionic acids (1a-e), into which a fibrate-like structure had been incorporated, were synthesised. Compound 1a was found to be a selective beta(3)-AR agonist in functional assays using the ferret detrusor (beta(3)-AR), rat uterus (beta(2)-AR), and rat atrium (beta(1)-AR); beta(3): EC(50)=7.8 nM, beta(2): IC(50)=7,300 nM, beta(1): EC(20)=23,000 nM. The introduction of a chlorine atom or methyl substituent at the ortho-position on the phenyl ring of 1a further improved beta(3)-AR selectivity. In an in vivo study, 1a lowered intrabladder pressure (ED(50)=31 microg/kg) in rats, without increasing heart rate, in keeping with the in vitro results. Consequently, it is proposed that 1a and its analogues (1b-e), possess beta(3)-AR agonistic activity in the absence of undesirable beta(1)- or beta(2)-AR mediated actions, and may be useful for clinical treatment and pharmacological studies.

Adrenergic beta-3 Receptor Agonists↗

PubMed2001

Malignant portal venous obstructions treated by stent placement: significant factors affecting patency.

PURPOSE: To identify factors affecting stent occlusion after stent placement in the portal vein in patients with malignant portal vein invasion. MATERIALS AND METHODS: Forty patients were studied. Twenty-three patients had hepatocellular carcinoma, nine patients had pancreatic cancer, and eight patients had bile duct cancer. Stents were placed in the portal venous system across stenotic (n = 28) or obstructive (n = 12) lesions after percutaneous transhepatic portography. Bare stents were used in 33 patients and covered stents were used in seven patients. Twenty-two variables were analyzed with use of univariate and multivariate analyses to identify significant factors affecting stent occlusion. RESULTS: Stents remained patent during a mean follow-up period of 11.9 months (range, 2-61 mo) in 60% of the patients. Stent occlusion was found in 40% of the patients, with a mean period until occlusion of 3.7 months (range, 0.2-16 mo). In the univariate analysis, the following five factors were significantly associated with a higher probability of stent occlusion: (i) splanchnic vein involvement, (ii) Child-Pugh class C, (iii) obstruction of the portal venous system, (iv) pancreatic cancer, and (v) lack of anticancer treatment after stent placement. In the multivariate analysis, the first three factors were found to have independent value for stent occlusion. CONCLUSIONS: Splanchnic vein involvement, severe hepatic dysfunction, and obstruction of the portal venous system are the most important factors affecting stent occlusion in patients with malignant portal vein invasion.

Adult↗

PubMed2001

Use of a catheter with a large side hole for selective catheterization of the inferior phrenic artery.

The authors report the use of a catheter with a large side hole in the catheterization of the right inferior phrenic artery (IPA) arising from the proximal portion of the celiac trunk. A 5-F catheter with a side hole on either the top or the right side of the superior portion near the tip was used in five patients with hepatocellular carcinoma fed by the right IPA, which could not be selected by a conventional coaxial technique. In all patients, a 3-F microcatheter was successfully advanced into the right IPA through the side hole of this catheter introduced into the celiac artery or the common hepatic artery.

Aged↗

PubMed2001

Expression of Rb, pRb2/p130, p53, and p16 proteins in malignant melanoma of oral mucosa.

We previously reported that pRb2/p130 gene, one of the Rb family members, was immunohistochemically abundantly expressed in well-differentiated oral squamous cell carcinomas, whereas in undifferentiated ones the expression was low. Oral malignant melanoma is extremely rare, however the prognosis is poor because it tends to locally invade tissue or metastasize and its biological behavior appears to be different from cutaneous malignant melanoma. The present study dealt with the expression of pRb2/p130, Rb, p53, and p16 in 13 cases of malignant melanoma of oral mucosa as revealed by immunohistochemical staining. The stage classification of the 13 patients was as follows; stage II: eight patients, stage III: three patients, and stage IV: two patients. pRb2/p130 was expressed in only two stage II-cases, neither of which have shown any evidence of recurrence or metastasis for over 14 years. Positive staining for Rb was found in three cases consisting of one stage II-case, one stage III-case, and one stage IV-case. p53 was expressed in two cases, one a stage II and the other a stage IV. Positive staining for p16 was found in seven cases consisting of four stage II-cases, two stage III-cases, and one stage IV-case. pRb2/p130 may be inversely correlated with the malignancy of oral malignant melanoma, but further study is needed.

Aged↗

PubMed2001

Clinicopathological features of serum TTV DNA-positive non-A-G liver diseases in Japan.

This study was undertaken to detect TTV DNA in serum samples from patients with non-A, non-B, non-C, non-E, and non-G (non-A-G) liver diseases and from blood donors, and to investigate the clinicopathological features of TTV infection including its prevalence and influence on liver disease. The study population consisted of 20 patients with non-A-G liver diseases (nine with chronic hepatitis (CH), six with liver cirrhosis (LC), and five with hepatocellular carcinoma (HCC), as well as 47 blood donors. Detection of TTV DNA was conducted with 200 &mgr;l of serum by the nested polymerase chain reaction. The detection rate of TTV DNA by subject category was CH 55.9; LC 66.7; HCC 60%; and blood donors 28%. Regarding blood biochemistry, TTV DNA-positive patients tended to show higher levels of aspartate aminotransferase and alanine aminotransferase, as well as lower levels of platelet counts. Long-term follow-up revealed that TTV DNA-positive patients exhibited characteristic, multiple peaks of alanine aminotransferase (ALT) levels. The histologic findings in the livers of TTV DNA-positive patients with CH consisted of moderate necro-inflammatory reactions. In conclusion, it is possible that the TTV genotype 1b infection caused liver injury.

Journal Article↗

PubMed2001

Characterization of a vitamin B12 compound from unicellular coccolithophorid alga (Pleurochrysis carterae).

A unicellular coccolithophorid alga, Pleurochrysis carterae, contained 125.4 +/- 1.2 microg of vitamin B12 per 100 g dry cell weight of the lyophilized algal cells. A vitamin B12 compound was purified from the lyophilized algal cells and partially characterized. The silica gel 60 TLC and reversed-phase HPLC patterns of the purified pink-colored compound were identical to those of authentic vitamin B12, but not those of vitamin B12 analogues inactive for humans. When 22-week-old B12-deficient rats which excreted substantial amounts of methylmalonic acid (75.5 +/- 12.3 mg/day) in urine were fed the P. carterae (10 g per kg diet)-supplemented diet for 12 d, urinary methylmalonic acid excretion (as an index of vitamin B12 deficiency) of the rats became undetectable and hepatic vitamin B12 level of the rats was significantly increased.

Animals↗

PubMed2001

Vitamin B-12-deficiency affects immunoglobulin production and cytokine levels in mice.

To clarify the role of B-12 in the immunological function, serum C3, IgM, IgG, IgE contents, splenocytes expression of CD4, CD8, and CD4 positive intracellular IFN-gamma and IL-4 were examined in B-12-deficient mice, and the effect of the administration of CH3-B-12 was also studied. Serum C3, IgM and IgG contents were lower in B-12-deficient mice than in the control mice. On the other hand, serum IgE content was significantly higher in B-12-deficient mice, and the value in CH3-B-12 administered mice, administered CH3-B-12 to B-12-deficient mice for 48 h before the end of feeding period, showed a tendency to recovery. CD4+CD8- cells and CD4+CD8-/CD4-CD8+ ratio in splenocytes were significantly higher in B-12-deficient mice than in control mice. CD4+IFN-gamma+ cells was significantly lower in B-12-deficient mice than in control mice, and CD4+IL-4+ was significantly higher in B-12-deficient mice than in control mice. These results suggest that B-12-deficiency causes CD4+CD8-T cells shift from the T helper type 1 to the T helper type 2, which participate in the IgE production and elevates CD4+CD8-/CD4-CD8+ ratio. Thus, B-12 plays a role in maintaining the immune function in mice.

Animals↗

PubMed2001

Effect of naturally occurring E2F-4 alterations on transcriptional activation and proliferation in transfected cells.

E2F is a family of transcription factors implicated in the regulation of gene expression required for progression through the G(1)-S transition. We have previously detected tumor-specific mutations at a trinucleotide repeat coding sequence of E2F-4 gene in a subset of human sporadic colorectal cancers. The purpose of this study was to investigate the potential functional consequences of these E2F-4 mutations. We transfected NIH3T3 fibroblasts with expression constructs containing wild-type as well as mutant E2F-4 cDNA, and the effect of the E2F-4 mutations on proliferation was examined. Alteration in transactivation of the E2F consensus promoter sequence was also examined by transient cotransfection of a E2F-4 with a DP-2 construct into cultured human cells. Transfected cell clones overexpressing mutant E2F-4 grew more rapidly and showed higher proliferative activity by increased immunohistochemical staining for proliferating cell nuclear antigen (PCNA). All three mutant forms of E2F-4 showed elevated transactivation of the E2F consensus promoter sequence. Thus, expression of mutant E2F-4s confers a growth advantage in vivo, and this effect may be related to the acquisition of a neoplastic phenotype.

3T3 Cells↗

PubMed2001

Prospective monitoring of the Epstein-Barr virus DNA by a real-time quantitative polymerase chain reaction after allogenic stem cell transplantation.

Epstein-Barr virus (EBV)-related lymphoproliferative disorder (LPD) is a serious complication of haematopoietic stem cell transplantation (HSCT). To clarify the frequency, natural course and risk factors for LPD, we prospectively monitored 38 allogeneic (allo)-HSCT patients, focusing on the use of anti-thymocyte globulin (ATG). We used a recently developed real-time polymerase chain reaction assay to monitor EBV genome load. The subjects consisted of 19 patients given ATG for conditioning and 19 patients not given ATG. Of the 19 patients given ATG, 47.4% (nine patients) had a significant increase in EBV genome load (10(2.5) copies/microg DNA). Of these nine patients, two developed LPD. Therefore, 10.5% of the patients receiving allo-HSCT with ATG developed LPD. In contrast, none of the 19 patients without ATG had a significantly increased EBV load. The increases in viral load were observed in the second or third month after HSCT. We found that the peak viral loads of LPD patients were > 10(4.0 ) copies/microg DNA. On the other hand, the viral loads of most patients with no symptoms were < 10(2.5) copies/microg DNA. In conclusion, routine monitoring of EBV load during the second and third months after transplantation may benefit patients undergoing HSCT with ATG. We propose that an EBV load > 10(2.5) copies/microg DNA is the reactivation of EBV, and that an EBV load > 10(4.0) copies/microg DNA is indicative of developing LPD.

Adolescent↗

PubMed2001

Cross talk of the interferon-alpha/beta signalling complex with gp130 for effective interleukin-6 signalling.

BACKGROUND: Signalling cross talk provides a molecular basis for modulating a given signalling pathway by another, and it is often critical for regulating cellular responses elicited by cytokines. Previously, we reported on the critical role of the IFN-alpha/beta signalling complex, generated by spontaneously produced IFN-alpha/beta, in efficient IFN-gamma signalling. RESULTS: In the present study, we have demonstrated that the IFN-alpha/beta signalling complex also contributes to efficient IL-6 signalling. In fact, IL-6-induced activation of the Stat1 and Stat3 transcription factors is markedly diminished in the absence of the IFN-alpha/beta signalling complex. The induction of several target genes for these factors is also diminished, both in vitro and in vivo. We provide evidence that the cytoplasmic tyrosine residues of IFNAR-1, which remains phosphorylated by a weak IFN-alpha/beta stimulation, provide docking sites for Stat1 and Stat3 to form homo- or heterodimers following IL-6 stimulation. Furthermore, a chemical cross-linking experiment revealed that IFNAR-1 and gp130, a common signal transducer for the IL-6 family of cytokines, exist in close proximity. CONCLUSIONS: The constitutive weak IFN-alpha/beta signal provides a foundation for strong cellular responses to IL-6, IFN-gamma, and possibly other cytokines. Our results also suggest the assembly of cytokine receptor subunits, which may represent a 'receptosome'-like structure, allowing the unique signalling cross talks to occur.

Animals↗

PubMed2001

In situ observation of the initial growth process of carbon nanotubes by time-resolved high resolution transmission electron microscopy.

We succeeded in plan-view dynamic observation of the initial formation process of carbon nanotubes from beta-SiC( 1 1 1) surfaces by time-resolved high resolution transmission electron microscopy. At 1360 degrees C, the flakes of graphite layers of a fibre orientation were formed on the SiC( 1 1 1) surfaces. From the graphite layers, carbon nanotubes were formed perpendicular to the ( 1 1 1) plane of the SiC. A scanning tunnelling microscopy observation showed that the end of carbon nanotube was closed. These results indicate that the caps of the carbon nanotubes are formed by a lift of a part of the graphene along the [ 1 1 1] direction of the SiC through generation of pentagons and heptagons. Two types of carbon nanotube, single-wall and double-wall, were observed in plan-view images. Different image intensity between an outer ring and an inner ring in double-wall nanotubes suggests that the inner layers of multiwall nanotubes are formed after the outer ones.

Journal Article↗

PubMed2001

Participation of ATP in cell volume regulation in the endothelium after hypotonic stress.

1. The role of ATP in the regulatory volume decrease (RVD) after hypotonic cell swelling was examined in cultured endothelial cells isolated from the rat caudal artery. 2. Hypotonic stress increased [Ca2+]i in addition to increasing the overflow of ATP and cell volume. The hypotonicity induced increase in [Ca2+]i was prevented by pyridoxalphosphate-6-azophenyl-1-2',4'-disulphonic acid (PPADS; a P2 purinoceptor antagonist), U-73122 (a phospholipase C inhibitor) and thapsigargin (a Ca2+ pump inhibitor). However, the hypotonicity induced increase in cell volume was potentiated by PPADS, U-73122 and thapsigargin. 3. Similar changes were observed in cells treated with 2-methylthioATP, a P2Y purinoceptor agonist, but not by alpha,beta-methylene ATP, a P2X purinoceptor agonist. Thus, it appears that the responses observed following hypotonic stress are mediated by activation of P2Y purinoceptors. 4. On the basis of these findings, it is suggested that ATP, which is released by hypotonicity, may participate in the RVD as a substantial regulator or initiator via P2 purinoceptor-induced increases in [Ca2+]i.

Adenosine Triphosphate↗

PubMed2001

Basaloid-squamous cell carcinoma of the esophagus: diagnosis based on immunohistochemical analysis.

Basaloid-squamous cell carcinoma of the esophagus (BSCC) is an extremely rare tumor. Histologically, this tumor should be differentiated from adenoid cystic carcinoma (ACC) and small cell undifferentiated carcinoma (SCUC). Biologically, this tumor is very aggressive, with a propensity for distant metastasis. We report a 64-year-old male with esophageal BSCC. The patient complained of dysphagia and was found to have a torous lesion in the esophagus on radiological examination. Upper gastrointestinal fiberscopy showed a localized ulcerative type tumor, which was diagnosed as squamous cell carcinoma (SCC) on biopsy. Surgery resulted in curative resection. A histological examination of the resected tumor showed features of BSCC. Immunohistochemical examination demonstrated AE3/1- and CAM 5.2-positive tumor cells, and laminin-positive cells in the periphery of the nests. These data were useful in differentiating this tumor from ACC and SCUC. Six months after surgery, the patient developed hepatic metastases, which were successfully treated by regional chemotherapy via the hepatic artery by using fluorouracil. The patient is currently being followed up at the outpatient clinic and shows no signs of any recurrence.

Biomarkers↗

PubMed2001

Advanced gastric cancer with multiple lymph node metastasis successfully treated with etoposide, adriamycin and cisplatin.

Gastric cancer usually shows poor sensitivity to chemotherapy, and the presence of lymph node metastases is associated with extremely poor prognosis, especially when the number of such nodes is more than 10. We report here a case of advanced gastric cancer with histopathologically confirmed metastases in 15 regional lymph nodes, in which the recurrent tumor was sensitive to combination chemotherapy. Distal gastrectomy with lymphadenectomy was performed for the primary tumor. A hard (recurrent) tumor was detected in the upper abdomen 5 months postoperatively. Abdominal CT revealed two tumors measuring 3.5 x 1.8 and 3.3 x 2 cm in diameter at the front of the pancreatic head, which suggested recurrence. Etoposide, adriamycin and cisplatin (EAP) chemotherapy (20 mg/kg adriamycin, 100 mg/kg etoposide and 50 mg/kg cisplatin (CDDP)) was administered every 6 weeks. The tumors regressed and became undetectable on CT after four cycles. At that stage, CDDP was replaced with 400 mg/kg carboplatin, which was administered every 1 or 2 months. The patient had no recurrence 8 years after surgery. For treatment of advanced gastric cancer with multiple lymph node metastases, a wide resection of the tumor should be performed followed by treatment of the residual tumor cells with a suitable combination chemotherapy taking into consideration the characteristics of the tumor and the condition of the host. We present a patient with gastric cancer and histopathologically confirmed metastases in 15 regional lymph nodes, who was successfully treated by surgery followed by EAP adjuvant chemotherapy. The patient remains alive and well at 8 years after surgery.

Adult↗