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Biomedical subjects

Toshiaki Watanabe

Publications and source records attributed to Toshiaki Watanabe.

At least 37 records · Page 2Linked to original sources

Elective colon and rectal surgery differ in risk factors for wound infection: results of prospective surveillance.

OBJECTIVE: The objective of this study was to clarify the incidence and risk factors for developing incisional surgical site infection (SSI) in both elective colon and rectal surgery. SUMMARY BACKGROUND DATA: SSI is a frequent complication after elective colorectal resection. The National Nosocomial Infection Surveillance system surveys all colorectal surgeries together, without differentiating the type of colorectal surgery performed. However, rectal surgery may have a higher risk for SSI, and identifying risk factors that are more specific to each procedure would be more predictive. METHODS: We conducted prospective SSI surveillance of all elective colorectal resections performed by a single surgeon in a single institution from November 2000 to July 2004. The data for colon and rectal surgeries were collected separately. The outcome of interest was incisional SSI. Univariate and multivariate analyses were performed to determine the predictive significance of variables in each type of surgery. RESULTS: A total of 556 colorectal resections, consisting of 339 colon and 217 rectal surgeries, were admitted to the program. The incisional SSI rates in colon and rectal surgeries were 9.4% and 18.0%, respectively (P = 0.0033). Risk factors for developing incisional SSI in colon surgery were ostomy closure (OR = 7.3) and lack of oral antibiotics (OR = 3.3), while in rectal surgery, risk factors were preoperative steroids (OR = 3.7), preoperative radiation (OR = 2.8), and ostomy creation (OR = 4.9). CONCLUSIONS: Colon and rectal surgeries differ with regard to incidence and risk factors for developing incisional SSI. SSI surveillance for such surgeries should be performed separately, as this should lead to more efficient identification of risk factors and a reduction in SSI.

Adolescent↗

hRFI overexpressed in HCT116 cells modulates Bcl-2 family proteins when treated with 5-fluorouracil.

Exogenous overexpression of hRFI, originally isolated in our laboratory, inhibits not only death receptor-mediated apoptosis but also the mitochondrial apoptosis induced by several chemotherapeutic agents including 5-fluorouracil (5-FU). Recently, it has become clear that hRFI targets and degradates caspase-8 and -10 in death receptor-mediated apoptosis by E3 ubiquitin activity in a ring finger domain homologous to that of X-chromosome-linked inhibitor of apoptosis protein (XIAP). However, the cellular mechanism of the inhibition of mitochondrial apoptosis by hRFI has not been fully elucidated. We prepared HCT116 overexpressing hRFI (HCT116/hRFI) cells and comprehensively analyzed the expression changes of 51 apoptosis-related genes with or without 5-FU treatment between HCT116/hRFI and mock cells using microfluidic low-density arrays. As a result, we identified four genes (Bcl-2, Bcl-XL, cIAP2, and CFLAR) whose expression was four or more times higher in HCT116/ hRFI cells than in HCT116/LacZ cells, and found that Bcl-2 and the ratio of Bcl-2/Bax or Bcl-2/Bak were upregulated when HCT116/hRFI cells were treated with 5-FU. Furthermore, we also validated the up-regulation of Bcl-2 and Bcl-XL in HCT116/hRFI cells treated with 5-FU by Western blot analysis. Such evidence suggests that the modulation of Bcl-2 family proteins seen in 5-FU treatment plays an important role in the anti-apoptotic function of HCT116/hRFI cells.

Antimetabolites, Antineoplastic↗

Chronic colitis promotes tumor development.

Patients with chronic ulcerative colitis have a significantly increased risk of colorectal cancer development. This study was aimed at clarifying whether colitis promotes tumor development or not. A dose of 200 mg/kg body weight 1,2-dimethylhydrazine was given to male Wistar rats. Four weeks later, 5% acetic acid (colitis group) or 0.9% saline (control group) was administered intrarectally once a week for 12 weeks and the rats were sacrificed after 27 weeks of dimethylhydrazine injection. Macroscopic lesions (ML) were more frequently detected in the colitis group than in the control group without statistical significance. However, the number of ML per rat with ML was largest in the colitis group (4.50 vs. 1.33; p=0.039). Eleven of 13 tumors were sessile in the colitis group, while three of five were pedunculated in the control group (p=0.044). All ML of 3 mm or more in diameter in the control group were intramucosal well-differentiated tumors. In the colitis group, 4 of 13 tumors were poorly or moderately differentiated or mucinous carcinomas, and 11 of 13 invaded the submucosal layer or deeper (p=0.003). The number of aberrant crypt foci per rat was smaller in the colitis group than in the control group. The number of crypt orifices was larger in the colitis group than in the control group (23.6 vs. 8.8: p<0.001). Significantly higher proliferative activity of normal-appearing mucosa was noted in the colitis group in all three parts of the colon. Colitis is suggested to promote colonic tumor development.

1,2-Dimethylhydrazine↗

[A treatment for pulmonary metastases from colorectal cancer by pre-operative CPT-11/5'-DFUR combination therapy].

There is no standardized consensus at each institution about a treatment for pulmonary metastases from colorectal cancer. A case of pulmonary radical resection can expect a good result. However, a result of a nonoperative case is extremely poor. A focal control until the time of operation to a metastatic lesion is very important. We want to have a safe and effective chemotherapy. We experienced a resectable case by CPT-11/5'-DFUR combination therapy.

Adenocarcinoma↗

Effect of cystathionine beta-synthase variant 844ins68bp and methylenetetrahydrofolate reductase A1298C polymorphisms in xenografts on 5-FU efficacy and doubling time.

The association of MTHFR and CBS variants with the doubling time and responsiveness to several chemodrugs was analyzed in 26 human cancer xenografts. The tumors homozygous for the absence of insertion (NN) for the CBS 844ins68bp were more chemosensitive than those with insertion (NI) to TS-1 (P=0.0048), suggesting a potential effect of this variant on fluoropyrimidine efficacy. Furthermore, the doubling time of tumors with a variant C allele (AC or CC) in MTHFR-A1298C was significantly longer than that of tumors with a normal allele (AA) (P=0.0008). Twenty-nine cellular proliferation-related genes were associated with MTHFR-A1298C genotyping and with the doubling time.

Antimetabolites, Antineoplastic↗

Lysophosphatidic acid-induced effects in human colon carcinoma DLD1 cells are partially dependent on transactivation of epidermal growth factor receptor.

BACKGROUND: Lysophosphatidic acid (LPA) is a lipid mediator of diverse effects on various cells. LPA is well known to induce phosphorylation of the epidermal growth factor receptor (EGFR), which is termed transactivation, in some cell types. In this study, we investigated the contribution of EGFR transactivation in LPA-induced responses in colon cancer DLD1 cells. MATERIALS AND METHODS: Immunoprecipitation was performed to investigate whether LPA induced EGFR phosphorylation. Then, we investigated LPA-induced migration and IL-8 secretion in DLD1 cells. Migration was measured in a modified Boyden chamber and IL-8 secretion was measured by ELISA. In these experiments we used an EGFR inhibitor, AG1478 or matrix metalloproteinase (MMP) inhibitor, GM6001. RESULTS: Immunoprecipitation analysis revealed that LPA induced a significant level of tyrosine phosphorylation of EGFR in DLD1 cells. The LPA-induced phosphorylation of EGFR was almost completely abrogated by either AG1478 or GM6001. LPA induced significant migration and IL-8 secretion in DLD1, both of which were significantly inhibited by AG1478 or GM6001. However, the inhibitory effects were only partial (migration; 29% +/- 2%, 32 +/- 13% inhibition, IL-8 secretion; 33% +/- 1%, 26% +/- 5% inhibition, respectively). CONCLUSION: These results clearly indicate that LPA acts upstream of EGFR and compensates the EGF signal and antagonism of the EGF signal cannot completely block tumor progression in colon cancer cells. Blockade of the LPA signal may have clinical significance in the treatment of colon cancer.

Cell Line, Tumor↗

Transactivation of epidermal growth factor receptor is involved in leptin-induced activation of janus-activated kinase 2 and extracellular signal-regulated kinase 1/2 in human gastric cancer cells.

Leptin is known to act as a growth factor through the Janus-activated kinase (JAK)/signal transducer and activator of transcription signaling pathway as well as the mitogen-activated protein kinase pathway. In this study, we showed a novel signal transduction pathway using two human gastric cancer cell lines, MKN28 and MKN74. Both gastric cancer cells expressed leptin and its receptors (Ob-R) at the protein level. We found that leptin, even at as low as 0.1 ng/mL, induced significant tyrosine phosphorylation of epidermal growth factor receptor (EGFR). Time-course experiments revealed that phosphorylation was maximal after 5 minutes of stimulation and declined thereafter. We also revealed that tyrosine phosphorylation of EGFR induced by leptin was significantly attenuated by two inhibitors, an EGFR tyrosine kinase inhibitor, AG1478, and a broad-spectrum matrix metalloproteinase inhibitor, GM6001. This indicates that the pathway of EGFR transactivation induced by leptin is dependent on proteolytically released EGFR ligands. Leptin induced JAK2 activation and extracellular signal-regulated kinase (ERK) 1/2 activation in these gastric cancer cells, both of which occurred after the peak of EGFR transactivation. Pretreatment of gastric cancer cells with AG1478 significantly reduced the degree of phosphorylation of both JAK2 and ERK1/2. These findings indicate the involvement of EGFR transactivation in the activation of JAK2 and ERK1/2. Our results reveal that EGFR transactivation is involved in the leptin signaling pathway in gastric cancer cells, which extends the physiologic action of leptin beyond its central effects in the hypothalamus to regulate body weight.

Cell Line, Tumor↗

Tumor budding and evidence-based treatment of T2 rectal carcinomas.

BACKGROUND: The validity of the histological criteria in deciding additional bowel resection after local excision of T2 rectal carcinomas is questioned. METHODOLOGY: In 72 T2 colorectal carcinomas resected by major surgery, the associations between lymph node metastasis (LNM) and clinicopathologic parameters were examined statistically, a prediction formula for LNM was constructed and decision analysis was attempted. RESULTS: Multivariate analysis showed that female gender and a greater number of tumor budding were significantly associated with LNM. The probability of LNM can be calculated as follows; Z = 0.037 x (budding number) + 2.08 x (SEX; male, 1; female, 2) - 5.736; Probability = 1/1 + e(-Z). When a 75-year-old patient has pulmonary complications, the operative risk is assumed to be over 2%. If a number of tumor budding is 0, the risk of LNM is calculated as 2.4% in a male and 17.1% in a female patient. On the assumption that the risk of liver metastasis is half of that of LNM, and the salvageabilities after LNM and liver metastasis are 20% and 50%, respectively, observation policy is justified for a male patient, whereas additional surgery should be undertaken for a female patient. CONCLUSIONS: A number of tumor budding may be useful for determining the individualized treatment of T2 rectal carcinomas.

Cell Differentiation↗

Lysophosphatidic acid transactivates both c-Met and epidermal growth factor receptor, and induces cyclooxygenase-2 expression in human colon cancer LoVo cells.

AIM: To examine whether lysophosphatidic acid (LPA) induces phosphorylation of c-Met and epidermal growth factor receptor (EGFR), both of which have been proposed as prognostic markers of colorectal cancer, and whether LPA induces cyclooxygenase-2 (COX-2) expression in human colon cancer cells. METHODS: Using a human colon cancer cell line, LoVo cells, we performed immunoprecipitation analysis, followed by Western blot analysis. We also examined whether LPA induced COX-2 expression, by Western blot analysis. RESULTS: Immunoprecipitation analysis revealed that 10 micromol/L LPA induced tyrosine phosphorylation of c-Met and EGFR in LoVo cells within a few minutes. We found that c-Met tyrosine phosphorylation induced by LPA was not attenuated by pertussis toxin or a matrix metalloproteinase inhibitor, in marked contrast to the results for EGFR. In addition, 0.2-40 micromol/L LPA induced COX-2 expression in a dose-dependent manner. CONCLUSION: Our results suggest that LPA acts upstream of various receptor tyrosine kinases (RTKs) and COX-2, and thus may act as a potent stimulator of colorectal cancer.

Cell Line, Tumor↗

Early-outgrowth of endothelial progenitor cells can function as antigen-presenting cells.

Endothelial progenitor cells (EPCs) have been recently found to exist circulating in peripheral blood of adults, and home to sites of neovascularization in peripheral tissues. They can also be differentiated from peripheral blood mononuclear cells (PBMNCs). In tumor tissues, EPCs are found in highly vascularized lesions. Few reports exist in the literature concerning the characteristics of EPCs, especially related to their surface antigen expressions, except for endothelial markers. Here, we aimed to investigate the surface expression of differentiation markers, and the functional activities of early-outgrowth of EPCs (EO-EPCs), especially focusing on their antigen-presenting ability. EO-EPCs were generated from PBMNCs, by culture in the presence of angiogenic factors. These EO-EPCs had the morphological and functional features of endothelial cells and, additionally, they shared antigen-presenting ability. They induced the proliferation of allogeneic lymphocytes in a mixed-lymphocyte reaction, and could generate cytotoxic lymphocytes, with the ability to lyze tumor cells in an antigen-specific manner. The antigen-presenting ability of EO-EPCs, however, was weaker than that of monocyte-derived dendritic cells, but stronger than peripheral blood monocytes. Since EO-EPCs play an important role in the development of tumor angiogenesis, targeting EPCs would be an effective anti-angiogenic strategy. Alternatively, due to their antigen-presenting ability, EO-EPCs can be used as the effectors of anti-tumor immunotherapy. Since they share endothelial antigens, the activation of a cellular immunity against angiogenic vessels can be expected. In conclusion, EO-EPCs should be an interesting alternative for the development of new therapeutic strategies to combat cancer, either as the effectors or as the targets of cancer immunotherapy.

Antigen-Presenting Cells↗

Heating and coagulation volume obtained with high-intensity focused ultrasound therapy: comparison of perflutren protein-type A microspheres and MRX-133 in rabbits.

PURPOSE: To compare the efficiency of different microbubble contrast agents in the heating and coagulation of rabbit liver tissue by using high-intensity focused ultrasound therapy. MATERIALS AND METHODS: The use of and protocols for Japan white rabbits were approved by the University of Tokyo Committee on Animal Resources. In vitro experiments were conducted in a 1-mL cylindric space of polyacrylamide gel, which contained different microbubble contrast agents (MRX-133 or perflutren protein-type A microspheres). In vivo experiments were performed in six Japan white rabbits (two for the perflutren protein-type A microsphere group, two for the MRX-133 group, and two for the control group). In each rabbit, the liver was directly subjected to high-intensity focused ultrasound after intravenous injection of different microbubble contrast agents. Natural saline was used as a control. High-intensity focused ultrasound was applied for 30 seconds by using a 2.18-MHz transducer, and the temperature increase and volume of coagulation necrosis were evaluated. Statistical analysis was performed by using an analysis of variance test, which was followed by a Student-Newman-Keuls test; a P value of <.05 was considered to indicate a statistically significant difference. RESULTS: In the MRX-133 group, the mean temperature increase was significantly greater and faster than that in the control group (P < .01) or in the perflutren protein-type A microsphere group (P < .05). In the perflutren protein-type A microsphere group, the mean temperature increase was greater and faster than that of the control group (P < .01) for both in vitro and in vivo experiments. The mean volume of the coagulation necrosis lesion was 117.9 mm3 +/- 48.4 (+/-standard deviation) for the MRX-133 group, 45.4 mm3 +/- 24.9 for the perflutren protein-type A microsphere group, and 17.7 mm3 +/- 9.0 for the control group. In the MRX-133 group, the mean volume of coagulation necrosis was significantly greater than that of the control or the perflutren protein-type A microsphere group (P < .01), and in the perflutren protein-type A microsphere group, the volume of coagulation necrosis was greater than that of the control group (P < .05). CONCLUSION: MRX-133 had greater efficiency than perflutren protein-type A microspheres in high-intensity focused ultrasound-induced heating and coagulation of rabbit liver tissue.

Animals↗

Mucinous carcinomas of the colon and rectum show higher rates of microsatellite instability and lower rates of chromosomal instability: a study matched for T classification and tumor location.

BACKGROUND: The clinicopathologic significance of mucinous carcinomas (Muc) of the colon and rectum has been widely discussed, but there have been few studies on Muc regarding genetic and epigenetic alterations. The current study analyzed genetic and epigenetic alterations of Muc to clarify their differences from well differentiated adenocarcinomas (WD). METHODS: Thirty-nine cases of Muc and 39 cases of WD were investigated. Cases of WD were matched with cases of Muc for T classification and tumor location. Microsatellite instability (MSI) status and loss of heterozygosity (LOH) of four loci (2p, 5q, 17p, 18q) were evaluated. The methylation status of the hMLH1 promoter region in Muc was also examined. RESULTS: "MSI tumors" were defined as those that showed MSI-high, and "chromosomal instability (CIN) tumors" were defined as those that showed LOH but not MSI-high. MSI tumors were significantly more frequent in Muc (30.8%) than in WD (5.1%). CIN tumors were significantly less frequent in Muc (53.8%) than in WD (87.2%). In Muc, MSI tumors were significantly more frequent in the proximal colon (55.6%) than in the distal colon (9.5%). Also, methylation of the hMLH1 promoter region in Muc was significantly more frequent in MSI tumors (83.3%) than in CIN tumors (27.8%) (P = 0.0077). CONCLUSIONS: When matched for T classification and tumor location, Muc shows higher rates of MSI and lower rates of CIN than WD.. Muc shows different characteristics according to tumor location, and methylation of the hMLH1 promoter region strongly correlates with Muc tumors showing MSI.

Adaptor Proteins, Signal Transducing↗

Use of a microbubble agent to increase the effects of high intensity focused ultrasound on liver tissue.

In order to find out whether high intensity focused ultrasound (HIFU) might be useful against hepatocellular carcinoma, we analyzed the effect of a microbubble agent (Levovist) on the temperature rise and tissue necrosis induced by HIFU. Rabbits were given 7 ml Levovist (300 mg/ml) or saline intravenously. Up to six areas per rabbit liver were exposed to HIFU for 60 s (2.18 MHz, I(SPTA)=400 W/cm(2)). The volume of the tissue coagulated by HIFU was measured 10 min after the start of HIFU. HIFU-induced lesions were larger in the animals given Levovist: (mm(3), Levovist versus saline) 371+/-104 versus 166+/-71 (P<0.001). Temperatures in the animals given Levovist were also higher 60 s after the start of exposure: ( degrees C, Levovist versus saline) 20.3+/-3.5 versus 13.2+/-3.8 (P<0.001). The amount of damage differed greatly, but the pathological changes caused by HIFU with Levovist were the same as those caused by HIFU with saline. Hemorrhagic areas and implosion cysts were seen, and many cells had been disrupted or destroyed. Microbubble agents developed for diagnostic uses could also be used in anticancer therapy.

Animals↗

Lysophospholipids transactivate HER2/neu (erbB-2) in human gastric cancer cells.

The ligand-less receptor HER2/neu (erbB-2) has been proposed as a prognostic marker of gastric cancer that correlates with poor clinical outcome, indicating that HER2 signals play an important role in gastric cancer progression. This study demonstrated that two major natural lysophospholipids, lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P), induce rapid and transient phosphorylation of HER2 in two human gastric cancer cell lines, MKN28 and MKN74 cells. We also revealed that tyrosine phosphorylation of HER2 induced by both lysophospholipids was significantly attenuated by two inhibitors, an epidermal growth factor receptor (EGFR) tyrosine kinase inhibitor, AG1478, and a broad-spectrum matrix metalloproteinase inhibitor, GM6001. This suggests that the pathway of HER2 transactivation induced by these lysophospholipids is dependent on the proteolytically released EGFR ligands. Our results indicate that LPA and S1P act upstream of HER2 in gastric cancer cells, and thus may act as potent stimulators of gastric cancer.

Electrophoresis, Polyacrylamide Gel↗