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Yasuhiro Yamada

Publications and source records attributed to Yasuhiro Yamada.

At least 55 records · Page 3Linked to original sources
PubMed2003

Lack of interleukin-1beta decreases the severity of atherosclerosis in ApoE-deficient mice.

OBJECTIVE: Atherosclerosis is considered to be a chronic inflammatory disease and many cytokines participate in the development of atherosclerosis. We focused on the role of interleukin-1beta (IL-1beta), one of the proinflammatory cytokines secreted by monocytes/macrophages, in the progression of atherosclerosis. METHODS AND RESULTS: We generated mice lacking both apoE and IL-1beta. The sizes of atherosclerotic lesions at the aortic sinus in apoE-/-/IL-1beta-/-mice at 12 and 24 weeks of age showed a significant decrease of approximately 30% compared with apoE-/-/IL-1beta+/+ mice, and the percentage of the atherosclerotic area to total area of apoE-/-/IL-1beta-/- at 24 weeks of age also showed a significant decrease of about 30% compared with apoE-/-/IL-1beta+/+. The mRNA levels of vascular cell adhesion molecule (VCAM)-1 and monocyte chemotactic protein-1 in the apoE-/-/IL-1beta-/- aorta were significantly reduced compared with the apoE-/-/IL-1beta+/+. Furthermore, VCAM-1 was also reduced at the protein level in apoE-/-/IL-1beta-/- aorta compared with apoE-/-/IL-1beta+/+. CONCLUSIONS: The lack of IL-1beta decreases the severity of atherosclerosis in apoE deficient mice, possibly through increased expressions of VCAM-1 and monocyte chemotactic protein-1 in the aorta.

Animals↗
PubMed2003

Tumor necrosis factor-alpha from bone marrow-derived cells is not essential for the expression of adhesion molecules in lipopolysaccharide-induced nasal inflammation.

Both the role and source of tumor necrosis factor (TNF-alpha) in lipopolysaccharide (LPS)-induced nasal inflammation were investigated using TNF-alpha gene deficient (TNF-alpha -/-) mice and chimeric mice that are TNF-alpha gene deficient only in bone marrow-derived cells. In the present study, intracellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) mRNA expression levels in the nasal mucosa were significantly decreased following intranasal instillation of LPS in TNF-alpha gene deficient mice compared to those in wild type mice. In contrast, ICAM-1 and VCAM-1 mRNA expressions were not significantly decreased although TNF-alpha mRNA expression was dramatically decreased in TNF-alpha gene deficient bone marrow-transplanted-chimeric (TNF-alpha -/--->+/+) mice compared to those in wild type bone marrow-transplanted-control (TNF-alpha +/+-->+/+) mice. These results indicate that the elevation of TNF-alpha mRNA in the nasal mucosa is mainly originated from bone marrow-derived cells. However, even low expression of TNF-alpha at local inflammation sites is sufficient to induce the expression of adhesion molecules in acute LPS-induced experimental rhinitis.

Animals↗
PubMed2003

Perilesional hyperintense rim of malignant hepatic tumors on ferumoxide-enhanced T1-weighted gradient-echo MR images: correlation between MR imaging and histopathologic findings.

PURPOSE: To correlate the perilesional hyperintense rim of malignant hepatic tumors seen on ferumoxide-enhanced T1-weighted gradient-echo (GE) MR images with histopathologic findings. MATERIALS AND METHODS: In 13 tumors in 12 patients, T1-weighted GE images (TE of 1.4 msec, flip angle of 90 degrees) obtained after IV administration of ferumoxide were evaluated. MR imaging was initiated within one hour of the completion of ferumoxide administration. Surgical resection for tumors was performed within an interval of two weeks of the MR imaging. Resected specimens were histopathologically examined for peritumoral sinusoidal congestion, desmoplastic reaction, compressed hepatic parenchyma, lymphocytic infiltration, and vascular proliferation. RESULTS: In twelve tumors (92%), prominently (N = 2), moderately (N = 5), and mildly to minimally (N = 5), a perilesional hyperintense rim was observed. Among histopathologic findings, the degree of peritumoral sinusoidal congestion correlated (R =.75, P <.04) with the degree of perilesional hyperintense rim. The thickness of the perilesional hyperintense rim showed a moderate positive correlation (R =.65, P <.02) with the thickness of peritumoral area with sinusoidal congestion. CONCLUSION: Perilesional hyperintense rim of malignant hepatic tumors on ferumoxide-enhanced T1-weighted GE images may correlate with sinusoidal congestion surrounding malignant hepatic tumors.

Aged↗
PubMed2003

Carcinoid tumor in the female urethral orifice: rare case report and a review of the literature.

We experienced an extremely rare tumor in the female urethral orifice in a 57-year-old Japanese woman. To our knowledge, only two cases of primary urethral carcinoid tumor have been reported. The previous reports of urethral carcinoid tumor were recognized in the male middle urethra and penile urethra. The present case was resected, and diagnosed as a carcinoid tumor by histological, immunohistochemical and ultrastructural findings. The tumor cells were stained by chromogranin A, synaptophsin and neuron-specific enolase, and neurosecretory granules were confirmed with electron microscopy. The patient did not complain of any symptoms until 5 years after the resection of the tumor. Therefore, the case we describe here is the first known report of carcinoid tumor in the Japanese female urethra.

Biomarkers, Tumor↗
PubMed2003

TNF-alpha contributes to the development of allergic rhinitis in mice.

BACKGROUND: Allergic rhinitis is an inflammation involving T(H)2-type cytokine production, with pathologic eosinophil infiltration in the nasal mucosa. Although TNF-alpha is thought to be a pro-inflammatory cytokine, the relationship between TNF-alpha and allergic rhinitis has not been clarified. OBJECTIVES: The role of TNF-alpha in a murine model of ovalbumin (OVA)-sensitized allergic rhinitis was investigated by using mice deficient in the gene encoding TNF-alpha (TNF-alpha(-/-) mice). METHODS: Both wild-type (TNF-alpha(+/+)) and TNF-alpha(-/-) mice were sensitized with OVA by means of intraperitoneal injection. They were then challenged with intranasal OVA, and various allergic responses were assessed. RESULTS: The production of OVA-specific IgE in the serum (P <.05) and the frequency of sneezes (P <.05) and nasal rubs (P <.05) decreased significantly in TNF-alpha(-/-) mice after OVA sensitization compared with that in TNF-alpha(+/+) mice (P <.05). The mRNA expression of IL-4, IL-10, and eotaxin in nasal mucosa in TNF-alpha(-/-) mice was also significantly suppressed compared with that in TNF-alpha(+/+) mice after OVA sensitization (P <.05). Furthermore, the expression of both endothelial-leukocyte adhesion molecule 1 and vascular cell adhesion molecule 1 mRNA in the nasal mucosa was significantly suppressed (P <.05), although intercellular adhesion molecule 1 mRNA expression did not decrease significantly in TNF-alpha(-/-) mice compared with that in TNF-alpha(+/+) mice after OVA sensitization. In addition, the effect of TNF-alpha on endothelial-leukocyte adhesion molecule 1 and vascular cell adhesion molecule 1 expression by means of Western blot analysis was compatible with the mRNA results. Pathologically, eosinophil infiltration in nasal mucosa was significantly restricted in TNF-alpha(-/-) mice compared with in TNF-alpha(+/+) mice after OVA sensitization (P <.05). CONCLUSION: TNF-alpha is necessary for antigen-specific IgE production and for the induction of T(H)2-type cytokines and chemokines. Furthermore, TNF-alpha might be important for the expression of adhesion molecules to recruit eosinophils to the allergic inflammatory site. We conclude that the lack of TNF-alpha inhibited the development of allergic rhinitis.

Animals↗
PubMed2003

Azoxymethane-induced beta-catenin-accumulated crypts in colonic mucosa of rodents as an intermediate biomarker for colon carcinogenesis.

It is now well established that bile acids act as colon tumor promoters. However, a previous study provided conflicting data showing that dietary exposure of cholic acid (CHA), a primary bile acid, inhibits the carcinogen-induced formation of aberrant crypt foci (ACF), possible preneoplastic lesions, in colonic mucosa of rodents. Recently we found beta-catenin-accumulated crypts (BCAC) in colonic mucosa of rats initiated with azoxymethane (AOM) and provided evidence that BCAC might be preneoplastic lesions independent from ACF. In the present study, we investigated the modifying effects of dietary CHA on the formation of BCAC as well as ACF in male F344 rats after exposure to AOM to determine if the differences in the effect of CHA on these lesions could account for this discrepancy. The results indicate that administration of CHA (0.5%) in the diet during the post-initiation phase significantly reduced the total number, multiplicity and size of ACF (P < 0.00001) in AOM-exposed colonic mucosa as reported previously. The number of ACF even with >4 aberrant crypts/focus was also decreased significantly (P < 0.0002), suggesting that the large ACF are little resistant to continuous feeding of 0.5% CHA diet. Interestingly, the dietary CHA significantly enhanced both the multiplicity (P < 0.002) and size (P < 0.00001), but not the incidence, of AOM-induced BCAC when compared with the control diet group. Importantly, the number of large BCAC with >6 crypts/lesion was increased significantly by the dietary CHA (P < 0.003). Our results support the concept that BCAC are precursors of colon tumors and indicate the usefulness of BCAC as intermediate biomarkers for colon carcinogenesis, although the methodology for their detection requires further improvement.

Animals↗
PubMed2003

beta-Catenin mutation is selected during malignant transformation in colon carcinogenesis.

Activating mutations in the beta-catenin gene is thought to be responsible for the excessive beta-catenin signaling involved in the majority of colon carcinomas in rodent models. Our recent study which indicated that beta-catenin mutations are present frequently in early dysplastic lesions of rat colon induced by a colon-specific carcinogen, azoxymethane led us to perform more specifically a comparative study regarding types of the beta-catenin mutation as well as K-ras mutations between such early appearing lesions and colon tumors. Male F344 rats, 6 weeks old, received s.c. injections of azoxymethane (15 mg/kg body weight) once a week for 3 weeks, and were killed at 16 and 46 weeks of age. Colons of animals killed at 16 weeks of age were processed for early altered lesions. Colon tumors from animals killed at 46 weeks of age were evaluated histopathologically. Laser capture microdissection system was used to obtain DNA of epithelial cells in both intramucosal lesions and colon tumors. After amplification of exon 3 of the beta-catenin gene and exon 1 of the K-ras gene, the products were then sequenced directly in both directions. Mutations in the exon 3 of beta-catenin gene were detected in 22 of 56 early lesions (39.3%) and 21 of 37 colon cancers (56.8%). Remarkably, all beta-catenin mutations detected in the colon tumors converged at codons encoding functionally important residues that may directly mediate beta-catenin degradation, whereas mutations in the early appearing lesions were found to be scattered in the exon 3 of the gene. K-ras mutations were also detected in 24 of 56 early lesions (42.9%) and 11 of 37 colon cancers (29.7%). All K-ras mutations converged at codon 12 and codon 13, even in the early lesions. The results of this study provide evidence for the first time that beta-catenin mutation is selected during the colon carcinogenesis. Our results also suggest that the activation of beta-catenin signaling pathway is not only an initiating event, but also plays a pivotal role in the promotion stage of colorectal carcinogenesis.

Animals↗
PubMed2003

A novel inflammation-related mouse colon carcinogenesis model induced by azoxymethane and dextran sodium sulfate.

To develop an efficient animal model for colitis-related carcinogenesis, male Crj: CD-1 (ICR) mice were given a single intraperitoneal administration (10 mg/kg body weight) of a genotoxic colonic carcinogen, azoxymethane (AOM), and a 1-week oral exposure (2% in drinking water) to a non-genotoxic carcinogen, dextran sodium sulfate (DSS), under various protocols. At week 20, colonic neoplasms (adenocarcinomas, 100% incidence with 5.60 +/- 2.42 multiplicity; and adenomas, 38% incidence with 0.20 +/- 0.40 multiplicity) with dysplastic lesions developed in mice treated with AOM followed by DSS. Protocols in which AOM was given during or after DSS administration induced a few tubular adenomas or no tumors in the colon. Immunohistochemical investigation of such dysplasias and neoplasms revealed that all lesions were positive for beta-catenin, cyclooxygenase-2 and inducible nitric oxide synthase, but did not show p53 immunoreactivity. The results indicate that 1-week administration of 2% DSS after initiation with a low dose of AOM exerts a powerful tumor-promoting activity in colon carcinogenesis in male ICR mice, and may provide a novel mouse model for investigating colitis-related colon carcinogenesis and for identifying xenobiotics with modifying effects.

Adenocarcinoma↗
PubMed2003

Inhibitory effects of troglitazone, a peroxisome proliferator-activated receptor gamma ligand, in rat tongue carcinogenesis initiated with 4-nitroquinoline 1-oxide.

Ligands for peroxisome proliferator-activated receptor (PPAR) gamma have been implicated in growth inhibition and cell differentiation in certain malignancies. In this study, the effects of troglitazone, a PPAR gamma ligand, given during the postinitiation phase of oral carcinogenesis initiated with 4-nitroquinoline 1-oxide (4-NQO) were investigated in male F344 rats. Rats aged 6 weeks were given 4-NQO at 20 ppm for 8 weeks to induce tongue neoplasms. Starting 1 week after the cessation of 4-NQO exposure, animals were fed diets containing 0, 30 or 100 ppm troglitazone for 22 weeks. At the end of the study (week 32), the incidences of 4-NQO-induced tongue neoplasms and preneoplasms were determined histopathologically and cell proliferation activity was estimated by counting bromodeoxyuridine (BrdU)-labeling indices and cyclin D1-positive cell ratios. In addition, immunohistochemical expression of cyclooxygenase (COX)-2 and PPAR gamma was assessed in the tongue lesions. Feeding with 100 ppm troglitazone significantly decreased the incidence of squamous cell carcinoma when compared to the group without troglitazone treatment (5.0% vs. 45.8%, P < 0.005). Interestingly, the BrdU-labeling index and cyclin D1-positive cell ratio assessed in the non-lesional tongue squamous epithelium were reduced by dietary administration of troglitazone (P < 0.0001-0.005). Additionally, the immunoreactivity of COX-2 in the tongue lesions was also decreased by the treatment (P < 0.01-0.05). These results clearly showed that dietary troglitazone inhibits 4-NQO-induced tongue carcinogenesis and such inhibition is related to suppression of increased cell proliferation and/or COX-2 expression. This study warrants further investigation on the use of PPAR gamma ligands as a novel preventive approach for oral malignancy.

4-Nitroquinoline-1-oxide↗
PubMed2003

Nucleotide sequences of genes encoding allosamidin-sensitive and -insensitive chitinases produced by allosamidin-producing Streptomyces.

Allosamidin is a strong inhibitor of family 18 chitinases. We previously reported the presence of allosamidin-sensitive and -insensitive chitinases (chitinase S and IS) in the culture filtrate of the allosamidin-producing strain, Streptomyces sp. AJ9463. In this study, we cloned and sequenced the genes encoding the two chitinases, which clarified that chitinase S and IS belong to the family 18 and 19 chitinase, respectively.

Acetylglucosamine↗
PubMed2003

[Clinical significance of MMP-3 in patients with rheumatoid arthritis: comparison with other inflammatory markers(IL-6, IL-8)].

We determined serum metalloproteinase-3(MMP-3) and inflammatory cytokine(IL-6, IL-8) levels in patients with rheumatoid arthritis(RA). Sera were obtained from 307 healthy subjects(female 140, male 167), 54 RA patients, and 17 osteoarthritis (OA). The MMP-3 concentrations in healthy female and male were 43.3 +/- 15.3 ng/ml and 90.7 +/- 26.0 ng/ml, respectively. The serum MMP-3 levels in male were significantly higher than those in female (p < 0.0001). MMP-3 levels in RA patients(259.1 +/- 34.2 ng/ml) were significantly higher than OA(43.6 +/- 6.1 ng/ml) or healthy controls. There was a significant correlation between MMP-3 and CRP(r = 0.586), IL-6(r = 0.345) levels in serum. In contrast, no significant correlation was observed between MMP-3 and IL-8(r = 0.19), or CA-RF(r = 0.052) levels. However, there were some cases with high MMP-3 levels in CA-RF-negative patients definitely diagnosed as RA. These findings suggest that MMP-3 determination is useful for the early diagnosis and the follow-up during the treatment for RA patients.

Adult↗
PubMed2003

Stabilization of affinity-tagged recombinant protein during/after its production in a cell-free system using wheat-germ extract.

We found that the affinity tag fused to the carboxyl (C-) terminal of a single-chain Fv (scFv) antibody was proteolytically degraded in a wheat germ cell-free protein synthesis system. The addition of two extra residues of glycine to the tail of the cMyc tag significantly increased the stability of the tag, suggesting that wheat endogenous carboxypeptidase(s) play a primary role in the C-terminal tag-specific degradation. In addition to the modification of the tag sequence, addition of diisopropyl fluorophosphate, which is known as an inhibitor of carboxypeptidases, prevented the cMyc tag sequence degradation. The effects of other protease inhibitors on the translation reaction and stability of the synthesized protein are also reported.

Journal Article↗
PubMed2002

Microadenomatous lesions involving loss of Apc heterozygosity in the colon of adult Apc(Min/+) mice.

Mutations in the human adenomatous polyposis coli (APC) gene are causative for familial adenomatous polyposis (FAP), a rare condition in which numerous colonic polyps arise during puberty and, if left untreated, lead to colon cancer. Mouse model for human FAP, Apc(Min/+) mouse, contains a truncating mutation in the Apc gene and spontaneously develops intestinal adenomas. However, the distribution of tumors along the intestine found in Apc(Min/+) mice is different from that in human FAP. A majority of intestinal polyps in the Apc(Min/+) mice is known to be located in the small intestine but rarely detected in the colon. We report here that adult Apc(Min/+) mice develop dozens of microadenomatous lesions in the colon (>20 lesions/colon). Surprisingly, the vast majority of such adenomatous lesions consisting of colonic crypts were <300 microm in their greatest dimension, whereas lesions in the small intestine showed various sizes. The allelic loss analysis revealed that these adenomatous crypts in the colon have already lost the remaining allele of Apc. Such findings suggest that, in contrast to tumorigenesis in the small intestine, loss of heterozygosity of the Apc gene is not sufficient for tumor development in the colon of Apc(Min/+) mice. Our results may give an account for the low incidence of colonic tumors in Apc(Min/+) mice.

Adenomatous Polyposis Coli↗
PubMed2002

Metachronous colon tumors: risk factors and rationale for the surveillance colonoscopy after initial polypectomy.

PURPOSE: We analyzed the possible risk factors for metachronous colon tumors after endoscopic resection of initial tumors. METHODS: Three hundred and twenty-one patients entered the surveillance study after colonoscopic resection of initial tumors between 1985 and 1999. Histology of initial tumors was adenoma in 214 patients and carcinoma in 107 patients. Solitary tumor was observed in 196 patients and multiple tumors in 125 at initial endoscopy. The median surveillance period was 39 (range, 12-112) months, and the median frequency of surveillance colonoscopy was three (range, 2-10) times. RESULTS: Metachronous neoplasms were identified in 114 of 321 surveillance cases (36%). In the 114 cases, the number of patients with metachronous adenoma was 103 (90%) and that of carcinoma was 11 (10%). Clinical characteristics at entry - including age, gender, multiplicity of polyp, histology of polyp, and site of polyp - were not different between patients with metachronous tumors and those without metachronous tumors. Kaplan-Meier analysis revealed that patients with a histology of carcinoma and those with multiple polyps at entry developed metachronous tumors significantly earlier than did patients with initial adenomas and initial solitary polyp, respectively ( P<0.001, P<0.001). However, other characteristics at entry did not produce significant differences in the rate of the development of metachronous tumors using Kaplan-Meier analysis. Proportional hazards model analysis revealed that histology of the initial tumor as carcinoma (relative risk, 1.690, 95% confidence interval, 1.118-2.555) and multiplicity (1.472, 1011-2.143) were significant risk factors for metachronous colon tumors. The 75%, 50%, and 25% metachronous tumor-free periods after initial polypectomy were 14, 21, and 39 months, respectively. CONCLUSIONS: These results may help optimizing surveillance strategies for metachronous colon tumors and raising the economic benefit of colonoscopy.

Adenocarcinoma↗
PubMed2002

Improved myocardial ischemia/reperfusion injury in mice lacking tumor necrosis factor-alpha.

OBJECTIVES: This study sought to assess the role of tumor necrosis factor-alpha (TNF-alpha) in myocardial ischemia/reperfusion (I/R) injury using TNF-alpha knockout (KO) mice. BACKGROUND: Tumor necrosis factor-alpha is thought to be involved in the pathogenesis of myocardial I/R injury by promoting leukocyte infiltration of the myocardium. However, the precise role of TNF-alpha in I/R injury is still unknown. METHODS: The hearts in TNF-alpha KO and wild-type (WT) mice were exposed by left lateral thoracotomy, and the left coronary artery was occluded for 30 min then reperfused for 120 min. RESULTS: The infarct size in TNF-alpha KO mice was significantly reduced compared with WT mice. The frequency of arrhythmia was decreased, and cardiac function during reperfusion was significantly improved in TNF-alpha KO mice compared with WT mice. The activation of nuclear factor-kappaB (NF-kappaB), the expression of chemokines and adhesion molecules and the infiltration of leukocytes were also significantly reduced in TNF-alpha KO mice, compared with WT mice. These findings provide evidence that TNF-alpha aggravates I/R injury. CONCLUSIONS: Tumor necrosis factor-alpha exacerbates myocardial I/R injury at an early stage of reperfusion by activating NF-kappaB, thereby inducing chemokines and adhesion molecules and facilitating leukocyte infiltration.

Animals↗