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Biomedical subjects

C Doi

Publications and source records attributed to C Doi.

At least 19 recordsLinked to original sources
PubMed2000

Expression of facilitative glucose transporter 1 mRNA in colon cancer was not regulated by k-ras.

The expression of facilitative glucose transporter isoforms in colon adenocarcinoma and the possible role of k-ras in inducing GLUT (glucose transporter) mRNA were studied. RT-PCR demonstrated GLUT2 and GLUT3 expression in 100% of the ten normal colon mucosa samples but detected no GLUT1 mRNA. By contrast, GLUT1 mRNA was detected in all 20 (100%) colon cancer samples examined. GLUT4 mRNA was not detected in either normal mucosa or colon cancer tissues. Semiquantitative PCR demonstrated equal amounts of GLUT2 and GLUT3 mRNA in both normal mucosa and colon cancer samples. A point mutation in codon 12 of k-ras was detected in only six of the 20 (30%) colon cancer samples. Thus, a major difference between normal colon epithelia and colon cancer was the acquisition of GLUT1 expression, which was unlikely to have been induced by a point mutation in codon 12 of k-ras.

Adenocarcinoma↗
PubMed2000

Suppression of facilitative glucose transporter 1 mRNA can suppress tumor growth.

We attempted to suppress glucose transporter 1 (GLUT1) expression by transfecting MKN45 cells with cDNA for antisense GLUT1. Glucose transport was significantly decreased in cells with antisense GLUT1 compared with wild-type cells or cells with vector alone. Suppression of GLUT1 mRNA resulted in a decreased number of cells in the S phase. This was accompanied by overexpression of p21 protein. Tumorigenicity in the nude mice injected with antisense GLUT1 expressing cells was significantly slower than in those with wild-type MKN45 cells. These results suggest that antisense GLUT1 mRNA inhibits tumor growth through a G(1) arrest and that expression of antisense GLUT1 mRNA via gene therapy can be used as a tool in the treatment of cancer.

Adenocarcinoma↗
PubMed2000

Effect of cyclooxygenase and nitric oxide synthase inhibitors on tumor growth in mouse tumor models with and without cancer cachexia related to prostanoids.

The potential interaction between cyclooxygenase (Cox) and NO metabolic pathways in the control of local tumor growth was evaluated. Mice bearing either a sarcoma-derived tumor (C57B1; MCG 101) or a malignant melanoma (C3H/HeN; K1735-M2) were used. These models were principally different because they demonstrate, in tumor hosts, conditions with and without cancer cachexia, seemingly related to high and low production of prostanoids, respectively. Cox inhibitors (Cox-1 and Cox-2) decreased tumor growth by 35-40% in MCG 101-bearing mice but had no such effect on melanoma-bearing mice, despite the expression of the Cox-2 protein in melanoma cells. Indomethacin reduced prostanoid production in both tumor (MCG 101) and host tissues and reduced tumor cell proliferation, mainly in vivo. Nitric oxide synthase (NOS) inhibitors (N(omega)-nitro-L-arginine methyl ester and N(omega)-nitro-L-arginine) reduced tumor growth in vivo by approximately 50% in both tumor models. Tumor growth reduction, related to NOS inhibition, was unrelated to prostanoid production and was an in vivo phenomenon in both tumor models. Specific inhibitors of inducible NOS activity, unexpectedly, had no effect in any tumor model, although inducible NOS protein was present in tumor tissues in large amounts. A combination of Cox and NOS inhibitors had no additive effect on tumor growth (MCG 101). Cox inhibition increased tumor tissue (MCG 101) expression of cNOS mRNA but had no significant effect on tumor tissue expression of the transferrin receptor, vascular endothelial growth factor, or basic fibroblast growth factor. NOS inhibition increased tumor tissue content of cNOS mRNA but showed as well a trend to increase mRNA content of the transferrin receptor and vascular endothelial growth factor. Our results suggest that NOS inhibitors can decrease the local growth of tumors that are either responsive or unresponsive to Cox inhibition. This effect may reflect cross-talk between Cox and NOS pathways within or among tumor cells, or it may represent unrelated effects on tumor and host cells. Whether NO inhibition may be used therapeutically in clinical tumors that are unresponsive to eicosanoid intervention remains to be evaluated.

Animals↗
PubMed2000

[Combined 5-FU and CDDP in a gastric cancer patient undergoing hemodialysis--pharmacokinetics of 5-FU and CDDP].

The pharmacokinetics of 5-FU and CDDP was examined in a gastric cancer patient receiving regular hemodialysis (HD) for renal failure. The patient received combination chemotherapy of 5-FU and CDDP, then on the day of HD we measured the plasma concentration of 5-FU, total platinum, and non-protein-bound platinum of the patient. In the present case, the 5-FU concentration was kept at an almost even level during HD. Non-protein-bound platinum disappeared after being maintained in blood for a certain time when HD was started 30 minutes after the end of CDDP administration. From these findings, we conclude that combined 5-FU and low-dose CDDP therapy should be done by decreasing the dose of 5-FU, administrating CDDP only on the day the patient undergoes HD, and starting HD 30 minutes after the end of CDDP administration.

Adult↗
PubMed1999

Expression of nitric oxide synthase in gastric cancer.

The expression of endothelial nitric oxide synthase (eNOS) and inducible nitric oxide synthase (iNOS) in samples of normal gastric mucosa and gastric cancer were examined by reverse transcriptase-polymerase chain reaction (RT-PCR) and semi-quantitative Western blot. In normal gastric mucosa, eNOS protein was found in all samples examined (mean, 70.2 +/- 60.1), relative to a standard protein. In gastric cancer specimens, eNOS protein was also detected in all samples, but the quantity (86.5 +/- 76.6) was not different from that found in samples of normal mucosa. The quantity of eNOS in gastric cancer tissues was negatively correlated with serosal invasion. iNbS mRNA, detected in nine of 18 cases, was slightly related to massive lymph node metastasis (n1-3 vs. n4). Neither tumor necrosis factor alpha (TNF-alpha) mRNA nor interleukin-6 (IL-6) mRNA was related to the expression of iNOS mRNA. These results suggest that iNOS not eNOS plays a role in gastric cancer tumor extension, but iNOS mRNA appears not to be induced by either TNF-alpha or IL-6.

Blotting, Western↗
PubMed1999

High incidence of synchronous cancer of the oral cavity and the upper gastrointestinal tract.

A high incidence of synchronous esophageal or gastric carcinoma in preoperative patients with carcinoma of the oral cavity was reported. Esophageal carcinoma was found in seven out of 56 patients (12.5%) and gastric cancer in five patients (8.9%) by videoendoscopy aided with lugol staining in the esophagus and indigocarmine solution in the stomach, although all patients were completely asymptomatic for these lesions. All patients were male, regular drinkers and heavy smokers. The depth of invasion of such tumors was limited to either mucosa or submucosa. Those esophageal and gastric lesions beside the primary oral cancers were positive for p53 protein by immunohistochemistry. Careful preoperative evaluation of not only the esophagus but also the stomach should be a routine procedure in patients with carcinoma of the oral cavity.

Aged↗
PubMed1999

Insulin resistance was connected with the alterations of substrate utilization in patients with cancer.

To elucidate the contribution of insulin resistance to substrate utilization, insulin sensitivity and substrate oxidation were examined in 19 cancer patients and five normal controls using the euglycemic hyperinsulinemic glucose clamp technique combined with indirect calorimetry. Glucose uptake and storage were significantly decreased in cancer patients compared with that of controls. In cancer patients, both glucose storage and oxidation were positively correlated with metabolized glucose as measured by the M value in cancer patients. Decrease in glucose uptake was mainly a reflection of decreased glucose storage rather than glucose oxidation. Inversely fat oxidation was negatively correlated with both the M value and glucose oxidation in cancer patients. In cancer patients with insulin resistance, decreased glucose uptake was closely associated with a rapid decrease in glucose storage, an increase in fat oxidation and a mild decrease in glucose oxidation, suggesting that insulin resistance was connected with the alterations of substrate utilization which may induce host depletion.

Adult↗
PubMed1999

Glucose uptake in the human gastric cancer cell line, MKN28, is increased by insulin stimulation.

The expression of the insulin-responsive glucose transporter (GLUT) 4 was studied in three histologically different human gastric cancer cell lines, MKN28, MKN45, and STSA. RT-PCR demonstrated GLUT1 and GLUT4 mRNA in all three cell lines. MKN28 cells expressed GLUT4 protein more than MKN45 and STSA cells by immunohistochemistry. Insulin stimulation of MKN28 cells resulted in a 22% increase in glucose uptake over that found under basal conditions (0.60 +/- 0.05 fmol/cell per min after insulin stimulation versus 0.53 +/- 0.07 fmol/cell per 3 min at basal). No increase in glucose uptake occurred with insulin stimulation in MKN45 or STSA cells. We conclude that the insulin responsive GLUT4 is expressed in MKN28, MKN45, and STKM1 human gastric cancer cell lines, albeit in different amounts. The greater expression of this transporter in MKN28 cells is likely responsible for the cell's ability to increase glucose uptake with insulin stimulation. However, the role played by GLUT4 in regulating the amount of glucose uptake would not be large in those human gastric cancer cell lines.

Biological Transport↗
PubMed1998

Insulin resistance in cancer patients is associated with enhanced tumor necrosis factor-alpha expression in skeletal muscle.

The roles of tumor necrosis factor (TNF)-alpha and the facilitative glucose transporter (GLUT) 4 on the induction of insulin resistance in peripheral tissues of cancer patients was examined by quantitative competitive PCR on biopsies of abdominal rectal muscle from patients with gastrointestinal cancer. The degree of insulin resistance in these patients was measured by the euglycemic hyperinsulinemic glucose clamp using a high physiologic insulin concentration (100 microU/ml). Quantitative competitive PCR was carried out using DNA competitors constructed by deleting 20-30 bp between the two primer annealing sites. Decreased glucose uptake (M value) in peripheral tissues was accompanied by a significantly increased TNF-alpha mRNA in skeletal muscle (r=0.867, p=0.0025). GLUT4 mRNA, however, was positively correlated with M values (r=0.739, p=0.015). The amounts of mRNAs for TNF-alpha and GLUT4 in skeletal muscle were not correlated. Serum TNF-alpha concentrations remained below the limit of detection. These findings suggest that the insulin resistance in peripheral tissues of cancer patients is in part due to the induction TNF-alpha mRNA and the down regulation of GLUT4 mRNA in peripheral tissues.

Female↗
PubMed1998

Circulating interleukin 6 concentrations and insulin resistance in patients with cancer.

BACKGROUND: The mechanism of insulin resistance in patients with cancer is not clear. This study was conducted to evaluate the possible role of circulating cytokines in inducing insulin resistance in patients with cancer. METHODS: Twenty-three patients with a variety of cancers were studied, including one patient with oesophageal cancer, 12 with gastric cancer, four with colon cancer and six with lung cancer. Six normal volunteers served as controls. Insulin resistance was evaluated by euglycaemic hyperinsulinaemic glucose clamp with a high physiological insulin concentration of 100 microunits/ml. Metabolized glucose, the M value, was compared between patients with cancer and controls. Serum concentrations of interleukin (IL) 6 and other cytokines (tumour necrosis factor (TNF) alpha, IL-8 and IL-10) were measured by enzyme-linked immunosorbent assay. RESULTS: The mean(s.d.) M value for patients with cancer (5.47(1.59) mg per kg per min) was significantly lower than that for controls (8.23(0.79) mg per kg per min) (P< 0.001). There was no relationship between the M value and degree of body-weight loss. Serum IL-6 concentration was measurable in eight of 23 patients: four with lung cancer, two with gastric cancer, and one each with oesophageal and colon cancer. None of the controls had a measurable serum IL-6 concentration. There was no significant relationship between serum IL-6 concentration and body-weight loss. TNF-alpha was undetectable in the serum of both patients with cancer and controls. Serum IL-8 and IL-10 were detected in seven and one of 23 patients respectively. These cytokines were not detected in the serum of controls. The M value was significantly smaller in those with measurable serum IL-6 (4.01(1.22) mg per kg per min) than in those with no measurable IL-6 (6.26(1.16) mg per kg per min) (P< 0.001). IL-6 and IL-8 levels were raised more frequently in the same patient but there was no significant relationship between IL-8 and M values. CONCLUSION: These results may suggest that IL-6 is related to insulin resistance in patients with cancer.

Aged↗
PubMed1998

Alteration in immunoexpression of glucose transporter 2 in liver of tumour-bearing rats.

To elucidate interactions between the glucose transport system and hepatic glucose production in the tumour-bearing state, glycogen storage, expression of glucose transporter isoform 2 (Glut 2) and activities of glucose-6-phosphatase (G-6-Pase) and hexokinase were histochemically examined in hepatocytes of tumour-bearing rats. Five male F344 rats, subcutaneously inoculated with methylcholanthrene (MCA)-induced sarcoma cells were compared with five pair-fed animals and four ad libitum fed controls. Glycogen storage was markedly decreased in liver cells of tumour-bearing rats compared to in those of control animals. Glut 2 immunoreactivity was uniformly seen in the cellular membrane of hepatocytes from control animals. In rats bearing sarcoma, the staining intensity was significantly decreased, suggesting that Glut 2 with its bi-directional transport capacity was down-regulated in the tumour-bearing state. Positive staining for hexokinase activity was located in the perivenous area in livers from control animals and was more diffusely located and more intense in livers from tumour-bearing animals. G-6-Pase activity, limited to the peripheral area in livers from controls, extended to the intermediate area and had stronger reactivity in livers from tumour-bearing animals. In the tumour-bearing cachectic condition, glucose may be partially consumed by a futile cycle, hepatic metabolic zonation was disturbed, and the release of glucose from the liver may not be mediated by a facilitative glucose transporter-2.

Animals↗
PubMed1998

Lectin histochemistry of dorsal skin of Wistar-derived hypotrichotic WBN/Ila-Ht rats.

A lectin histochemical study was carried out on the dorsal skin of Wistar-derived hypotrichotic WBN/Ila-Ht rats (HtRs) and Wistar rats (WRs) at 3, 7 and 24 weeks of age to clarify the lectinhistochemical characteristics of the skin during their development. The lectins examined were Concanavalia ensiformis (Con A), Dolichos biflorus agglutinin (DBA), Griffonia simpliciolia (GS-I), Helix pomatia agglutinin (HPA), Arachis hypogaea (PNA), Glycine maximus agglutinin (SBA), Ulex europeus agglutinin (UEA-I) and Triticum vulgaris agglutinin (WGA). None of the nucleated cell layers of the epidermis had DBA-binding sites, but they were all stained intensely with HPA and weakly with Con A irrespective of the strain and age of the rats. As to the other 5 lectins, the intensity of binding activity was generally weaker in HtRs than in WRs and at 3 weeks of age than at 7 or 24 weeks of age, respectively. Among them, UEA-I mainly bound to the spinous cell layer but not to the basal cell layer, suggesting that alpha-L-fucose would be expressed on the cell surface according to the differentiation of keratinocytes. In addition, GS-I, HPA and UEA-I bound to the hair follicle epithelium and many lectins stained sebaceous gland epithelial cells. In conclusion, except for the binding intensity of some lectins, there were no specific differences between HtRs and Wrs in the lectinhistochemical characteristics of the dorsal skin epidermis. The present data on the rat skin would be useful from the viewpoint of comparative lectinhistochemistry.

Animals↗
PubMed1995

Encephalomyocarditis (EMC) virus infection in the common vole, Microtus arvalis.

Encephalomyocarditis (EMC) virus infection in the common vole was examined for the first time. Sixteen 8-week-old males inoculated intraperitoneally with 10(5) plaque-forming units (pfu)/animal of the D variant of EMC virus were killed 3 and 7 days after inoculation (3 and 7 DAI). Viral replication was detected in the brain (10(5) pfu/g), heart (10(4) pfu/g) and pancreas (10(7) pfu/g) of all 8 animals at 3DAI. It was found in the pancreas (10(3) pfu/g) of all 8 animals and in the brain (10(4) pfu/g) of 2 of 8 animals at 7 DAI. Histopathological changes were observed in the brain (mild mononuclear cell infiltration around capillaries and sporadic pyknosis of neurons), heart (minimal myocardial necrosis) and pancreas (prominent acinar cell necrosis with inflammatory exudation) at 3DAI. At 7 DAI, replacement of necrotic tissues by mesenchymal cells and regeneration of acinar cells were conspicuous in the pancreas. Throughout the experimental period, no evidence for diabetogenic effect was found.

Animals↗