PubMed Health⌕ Search

Biomedical subjects

Kohji Miyazaki

Publications and source records attributed to Kohji Miyazaki.

At least 19 recordsLinked to original sources
PubMed2006

Tumor-stromal cell interaction under hypoxia increases the invasiveness of pancreatic cancer cells through the hepatocyte growth factor/c-Met pathway.

The hypoxic environment in tumor is reported to play an important role in pancreatic cancer progression. The interaction between stromal and cancer cells also contributes to the malignant behavior of pancreatic cancer. In the present study, we investigated whether hypoxic stimulation affects stromal as well as pancreatic cancer cells. Our findings demonstrated that hypoxia remarkably elevated the HIF-1alpha expression in both pancreatic cancer (PK8) and fibroblast cells (MRC5). Hypoxic stimulation accelerated the invasive activity of PK8 cells, and invasiveness was thus further accelerated when the hypoxic PK8 cells were cultured with conditioned medium prepared from hypoxic MRC5 cells (hypoxic conditioned medium). MMP-2, MMP-7, MT1-MMP and c-Met expressions were increased in PK8 cells under hypoxia. Hypoxic stimulation also increased the hepatocyte growth factor (HGF) secretion from MRC5 cells, which led to an elevation of c-Met phosphorylation in PK8 cells. Conversely, the elevated cancer invasion, MMP activity and c-Met phosphorylation of PK8 cells were reduced by the removal of HGF from hypoxic conditioned medium. In immunohistochemical study, the HIF-1alpha expression was observed in surrounding stromal as well as pancreatic cancer cells, thus indicating hypoxia exists in both of cancer and stromal cells. Moreover, the stromal HGF expression was found to significantly correlate with not only the stromal HIF-1alpha expression but also the c-Met expression in cancer cells. These results indicate that the hypoxic environment within stromal as well as cancer cells activates the HGF/c-Met system, thereby contributing to the aggressive invasive features of pancreatic cancer.

Blotting, Western↗
PubMed2006

Odd variation of 75 g oral glucose tolerance test results in a Japanese patient with polycystic ovary syndrome: a case report.

We report a young woman of normal body weight who was diagnosed with polycystic ovary syndrome (PCOS) and had an odd variation of 75 g oral glucose tolerance test (OGTT). This woman underwent the 75 g OGTT to evaluate the association between PCOS and insulin secretion capacity. Although the blood sugar levels were within normal range before the OGTT load test, we noted an odd variation of insulin response in which a condition of hyperinsulinemia after the load test was followed suddenly by hypoglycemia. Hyperandrogenism in the PCOS patient and insulin resistance indicated by 75 g OGTT suggest that insulin may influence the ovary and that there could be an association between this disease and insulin resistance. The insulinogenic index in this case showed higher than normal values, demonstrating that there was a positive correlation between hyperinsulinemia and insulin resistance. This patient experienced ovulation followed by pregnancy after treatment with an herbal medicine called Shakuyaku-Kanzo-To. We believed that identifying the subset of PCOS woman who is insulin resistant may be useful, as this resistance could be import in terms of follow-up and future exploration.

Adult↗
PubMed2006

Glucose intolerance in Japanese patients with polycystic ovary syndrome.

BACKGROUND: Hyperinsulinemia, which is related to obesity, played a pathogenic role in polycystic ovary syndrome (PCOS). However, the incidence of obesity in Japanese women with PCOS is different from that reported in patients with PCOS in Europe and USA. We should determine if insulin resistance occurs in Japanese PCOS. The purpose of this study is to assess the presence of insulin resistance in Japanese PCOS, while also considering obesity as a factor. METHODS: We divided the patients with polycystic ovary (PCO) into three groups based on body mass index and levels of gonadotropin. Nine obese PCOS, 34 normal body-weighted PCOS (luteinizing hormone (LH)/follicle stimulating hormone (FSH) >1.0) and 11 normal LH (LH/FSH </= 1.0), normal body-weighted PCO were studied. We compared those patients to 16 control subjects with normal ovulation or with hypothalamic anovulation. Eleven women in the control were normal body-weighted and five were obese. Patients were given an oral glucose tolerance test. Testosterone, plasma glucose and serum immunoreactive insulin after oral administration of 75 g dextrose were studied. We also compared glucose-intolerance [total plasma glucose (SigmaPG) and insulin (SigmaIRI), insulinogenic index (I.I.), fasting plasma glucose/immunoreactive insulin (FPG/IRI), homeostasis model assessment of insulin resistance (HOMA-R)] and testosterone among these groups. RESULTS: There were no differences in SigmaPG, SigmaIRI, I.I., FPG/IRI or HOMA-R between PCOS and controls. However, there were significant differences in SigmaPG, SigmaIRI, FPG/IRI and HOMA-R between obese and normal body-weighted patients. Similarly, there were no differences in SigmaPG, SigmaIRI, I.I., FPG/IRI or HOMA-R between PCOS and controls in the normal body-weighted group. However, there were significant differences in SigmaPG, SigmaIRI, FPG/IRI and HOMA-R between the obese and the normal body-weighted PCOS. There were also significant differences in SigmaPG and I.I. between LH-dominant, normal body-weighted PCOS and normal LH PCO. CONCLUSION: Japanese PCOS might have insulin-resistance but the factor of obesity had a stronger effect on insulin-resistance than did the existence of PCOS. The possibility of a different type of glucose-intolerance was suggested in the patients with ultrasonographical PCO in whom gonadotropin secretion was abnormal.

Adolescent↗
PubMed2006

Dopamine D(2) receptor expression and regulation of gonadotropin alpha-subunit gene in clonal gonadotroph LbetaT2 cells.

This study investigated the role of dopamine on the regulation of gonadotropin secretion at the gonadotroph cell line. We examined the function of the dopamine D(2) receptor in the regulation of pituitary gonadotropin gene expression using LbetaT2 cells, a mature, well differentiated clonal gonadotroph cell line. The presence of the dopamine D(2) receptor in the LbetaT2 cells was confirmed by both RT-PCR and Western blot. Gonadotropin releasing hormone (GnRH) stimulation resulted in gonadotropin LHbeta, FSHbeta and alpha-subunit promoter activation, and none were inhibited by quinpirol, a specific dopamine D(2) receptor agonist. Pituitary adenylate cyclase-activating polypeptide (PACAP) increased gonadotropin alpha-subunit promoter activity, but not LHbeta and FSHbeta promoter activity. The activity of PACAP was significantly inhibited in the presence of quinpirol. The protein kinase A inhibitor, H89, also inhibited PACAP-induced alpha-subunit gene expression. PACAP increased intracellular cAMP more than GnRH did in LbetaT2 cells, and the elevation of cAMP was strongly inhibited in the presence of various dopamine D(2) agonists. These results suggest that in pituitary gonadotrophs, the dopamine D(2) receptor is a negative regulator of gonadotropin alpha-subunit gene expression which is induced by cAMP-elevating factors in a cAMP-dependent pathway.

Animals↗
PubMed2006

Expression and activation of mitogen-activated protein kinase in the human endometrium during the menstrual cycle.

OBJECTIVE: The purpose of this study was to investigate the fluctuation of expression and activation of mitogen-activated protein kinase in normal human endometrium throughout the menstrual cycle. STUDY DESIGN: Thirty-three normal endometrial tissues were obtained from fertile women who had undergone hysterectomies for reasons other than endometrial disease. Extracellular signal-regulated kinase, -1, and -2 expression were studied by immunohistochemistry. Moreover, extracellular signal-regulated kinase activity was analyzed by gel kinase assay. RESULTS: Western blotting analysis with anti-pan-extracellular signal-regulated kinase antibody mainly demonstrated an immunoreactive band of 42 kd that corresponded to extracellular signal-regulated kinase 2 in the endometrium. The expression of extracellular signal-regulated kinase 2 tended to increase in the secretory phase. Immunohistochemical analysis for extracellular signal-regulated kinase 1 in endometrial sections revealed a weak staining of glands and almost no staining of stromal cells. Immunohistochemical analysis for extracellular signal-regulated kinase 2 in endometrial sections revealed a distinct staining of glands in both proliferative and secretory phases and a weak staining of stromal cells. Although the intensity of staining for extracellular signal-regulated kinase 2 in stromal cells did not change during the secretory phase, in the glands the extracellular signal-regulated kinase 2 was highly stained in the mid-to-late secretory phase. In gel kinase assay revealed that extracellular signal-regulated kinase activity was increased significantly in the mid-to-late secretory phase. CONCLUSION: Expression and activation of extracellular signal-regulated kinase in the human endometrium was increased particularly during the secretory phase. We suggest that fluctuation of extracellular signal-regulated kinase in the human endometrium may be induced by ovarian steroid hormones.

Adult↗
PubMed2006

Left ventricular hypertrophy in mice with a cardiac-specific overexpression of interleukin-1.

Recent studies have identified the importance of proinflammatory cytokines in the development of left ventricular (LV) hypertrophy. However, the precise role of interleukin-1 (IL-1), one of the major proinflammatory cytokines, in the myocardium is not fully understood. In this study, we investigated the pathophysiological consequences of cardiac expression of IL-1 in vivo. We generated mice with a cardiac-specific overexpression of human IL-1alpha. We then analyzed their heart morphology and functions. Histological and echocardiographic analyses revealed concentric LV hypertrophy with preserved LV systolic function in the mice. Our results suggest that myocardial expression of IL-1 is sufficient to cause LV hypertrophy.

Animals↗
PubMed2006

Expression of new human inorganic pyrophosphatase in thyroid diseases: its intimate association with hyperthyroidism.

Inorganic pyrophosphatase (PPase) controls the level of inorganic pyrophosphate produced by biosynthesis of protein, RNA, and DNA. Thus, PPase is essential for life. PPase expression is unclear in the thyroid. We cloned a new human PPase, phospholysine phosphohistidine inorganic pyrophosphate phosphatase (LHPPase), and established a rabbit polyclonal anti-LHPPase antibody. This is the first study to determine the PPase expression by immunohistochemistry and Western blot. Intranuclear LHPPase expression of thyrocytes was enhanced most prominently in Graves' disease and autonomously functional thyroid nodule. To estimate a regulating factor of subcellular localization of LHPPase, we examined its expression of Graves' disease-derived thyrocytes in vitro with the disease-originated serum. Nuclear expression of LHPPase was lost in cultured thyrocytes even with the serum, while its cytoplasmic expression was retained. The data suggest that increased expression of LHPPase is associated with hyperthyroidism. Intranuclear expression of LHPPase may not be regulated by Graves' disease-derived serum factors.

Antibodies↗
PubMed2006

Aberrant promoter hypermethylation in biliary tract carcinoma.

Biliary tract carcinoma is a relatively rare tumor with a poor survival rate. The molecular biological mechanisms underlying the development of biliary tract carcinomas are not well understood. Promoter methylation is an important epigenetic mechanism for suppressing tumor-suppressor gene activity. There is limited information regarding the abnormal methylation of cancer-related genes in biliary tract carcinoma; however, a few insights have been obtained into the role of epigenetic silencing in the progression of biliary tract carcinoma. In this review, we summarize recent data on gene silencing by promoter hypermethylation, and we discuss the implications for biliary tract carcinomas.

Bile Duct Neoplasms↗
PubMed2006

Gastrointestinal function and quality of life after pylorus-preserving pancreatoduodenectomy.

The pylorus-preserving pancreatoduodenectomy (PPPD) has taken the place of the conventional Whipple pancreatoduodenectomy as the standard procedure for various periampullary disease. With recent advances in surgical techniques and improvements in perioperative management, the number of long-term survivors after PPPD is increasing. As a result, surgeons should pay more attention to the patients' postoperative gastrointestinal function, nutrition, and quality of life (QOL). Gastric stasis, which is a frequent complication during the early postoperative period after PPPD, prolongs the hospital stay and impairs the QOL in the intermediate term. Several possible pathogeneses for this gastric stasis have been postulated; however, the precise mechanism remains unclear. The gastric emptying function gradually recovers to the preoperative level by 6 months after PPPD. Pancreatic functions are likely to be maintained for at least 1 year after PPPD; however, in some cases, they tend to gradually deteriorate over time after the operation, depending on the type of pancreatic reconstruction or the preoperative condition of the pancreas. It is important to note that preoperative and postoperative pancreatic exocrine function strongly influence the postoperative outcome regarding such factors as pancreatic fistula, body weight maintenance, nutrition, and the QOL. The QOL, as assessed by questionnaire, normally returns to the preoperative level within 6 months after PPPD, and this correlates with the changes in gastrointestinal function and nutritional status. It still remains an unresolved question, however, whether the Billroth-I PPPD really leads to better long-term nutritional status, but worse early gastric emptying function, than the Billroth-II type of reconstruction.

Gastric Emptying↗
PubMed2006

The significance of aberrant CHFR methylation for clinical response to microtubule inhibitors in gastric cancer.

BACKGROUND: We studied the correlations between CHFR (checkpoint with FHA and RING finger) gene methylation and responses to microtubule inhibitors (MI) in gastric cancer. METHODS: We examined 9 gastric cancer cell lines and 46 gastric cancer specimens from patients who underwent surgical resection. Promoter methylation was determined by methylation-specific polymerase chain reaction (MSP). CHFR mRNA expression was estimated by quantitative reverse transcription-PCR. The MI-induced growth inhibition was assayed by a standard MTT method. RESULTS: CHFR expression was silenced by aberrant promoter methylation in 3 of 9 gastric cancer cell lines. The level of CHFR mRNA expression was closely correlated with IC(50) in the MI-treated cells (R=0.889, P=0.005). In 46 patients with gastric cancers, 24 (52%) presented aberrant CHFR methylation. Among them, 12 patients had received treatment with MI because of advanced-stage tumor or tumor recurrence after surgery. The responders to the MI treatment were 29% in patients with CHFR methylation and 20% in those without the methylation. However, 6 (86%) of 7 patients with methylated CHFR tumor showed some regression or no progression, whereas 4 (80%) of 5 patients with unmethylated CHFR tumor manifested progressive deterioration. CONCLUSIONS: These observations indicated that CHFR methylation may be a clinically useful approach to predict the responsiveness of gastric cancers to treatment with MI.

Adult↗
PubMed2006

Iliac lymph node metastasis of an unknown primary tumor: report of a case.

Metastasis to the lymph nodes around the iliac vessels from cancer of an unknown primary (CUP) tumor has not yet been reported in either the English or Japanese literature and it is therefore described herein for the first time. The patient was a 70-year-old woman with persistent right leg edema. Computed tomography (CT) displayed a mass around the iliac vessels while physical, laboratory, and other imaging examination did not show any other tumor. Preoperatively diagnosed as a retroperitoneal tumor, the patient underwent a tumor resection, but a histopathological examination revealed the tumor to be poorly differentiated squamous cell carcinoma. Only residual lymph nodes in the pelvis were detected by postoperative fluorine-18 fluorodeoxyglucose-positron emission tomography. Neither a primary lesion nor any signs of recurrence were demonstrated for 13 months after radiotherapy for the residual nodes. We herein discuss the diagnosis, treatment, and follow-up of this less common CUP.

Aged↗
PubMed2006

Ethanol injection for ablation of an intractable digestive tract fistula: report of a case.

We successfully occluded an intractable digestive tract fistula by injecting it with absolute ethanol after all other treatments failed. A 48-year-old man suffered from a complex and relapsing digestive tract fistula after curative surgery for advanced colon cancer invading the pancreas and duodenum. After conservative management by fasting, drainage, and irrigation failed, fibrin glue infusion achieved only transient occlusion. We performed surgical repair and he was discharged from hospital, at which time fistulography showed no fistula. However, 1 month later fistulography showed that the fistula had recurred and involved the transverse colon, stomach, and intrahepatic bile duct via the jejunum. Finally, we gave five injections of absolute ethanol into the fistula, which resulted in complete occlusion within 6 months. Considering its clinical efficacy, safety, and cost efficiency, we think that ethanol sclerotherapy is a feasible treatment for intractable digestive tract fistula when conservative therapy fails.

Ethanol↗
PubMed2006

Primary colonic malignant melanoma.

Primary malignant melanoma originating in the digestive tract is extremely rare. A case of primary malignant melanoma in the descending colon is described. The tumor was an elevated mass with surface necrosis. Histologically, tumor cells were arranged with compact nests surrounded by fibrous stroma. The tumor cells had pleomorphic nuclei and rich cytoplasm. In some areas, cells of signet ring-like appearance were found. An immunohistochemical examination showed that most of the tumor cells were positive for S-100 protein, HMB-45, melan-A, vimentin and CD38. Ultrastructural examination confirmed some premelanosomes. EWS-ATF-1 fusion transcript, which is usually detected in clear cell sarcoma, was not demonstrated on reverse transcriptase-polymerase chain reaction. Because there was no evidence of either cutaneous or ocular primary melanoma, the tumor was thus diagnosed as primary colonic malignant melanoma. The patient has remained free of recurrent disease for 3 years after a surgical resection. Colonic malignant melanoma must be differentiated from other intestinal tumor, and the possibility of metastasis from another more common primary site must be ruled out.

Adenocarcinoma↗
PubMed2006

Deficient expression of the DPD gene is caused by epigenetic modification in biliary tract cancer cells, and induces high sensitivity to 5-FU treatment.

5-FU is the drug most frequently used to treat biliary tract cancer, while dihydropyrimidine dehydrogenase (DPD) is known to be a principal factor in 5-FU drug resistance. However, whether DPD activity and mRNA levels correlate with response to 5-FU is unknown for biliary tract cancers. The precise mechanism of DPD regulation also remains to be elucidated. In the present study, we quantitatively analyzed DPD mRNA in 8 biliary tract cancer cell lines using real-time RT-PCR, and assessed whether DPD mRNA levels correlate with DPD activity or the sensitivity to 5-FU. Finally, we examined the epigenetic gene silencing of DPD using one of the 8 lines, a gallbladder cancer cell line with deficient DPD expression, KMG-C. Strong correlation was found between DPD activity and DPD mRNA expression in the 8 cancer cell lines (R=0.797, P=0.0148). DPD mRNA expression and DPD activity exhibited positive correlation with the IC50 for 5-FU (R=0.658, R=0.644, respectively), although these relationships were not statistically significant. In the KMGC cells with deficient DPD mRNA levels, restoration of DPD expression was observed by 5-Aza-2' deoxycytidine (5-aza-C) treatment in a dose-dependent manner, suggesting gene suppression by promoter hypermethylation. Combined bisulfite restriction analysis was performed to analyze the methylation on CpG islands around the 5'-flanking region and intron 1 of the DPD gene, however, no methylated CpG sites were identified in these regions. In addition, the restored DPD expression level was more strongly induced by the histone deacetylase (HDAC) inhibitor, trichostatin A (TSA), than 5-aza-C treatment. These findings suggest that other mechanisms, including histone modification, may be important for DPD suppression. In conclusion, these results may aid the selection of 5-FU chemotherapy following determination of DPD expression in biliary tract cancers. Furthermore, epigenetic gene silencing appears to be an important mechanism of DPD suppression in biliary tract cancer.

Antimetabolites, Antineoplastic↗
PubMed2005

Differential expression of Janus kinase 3 (JAK3), matrix metalloproteinase 13 (MMP13), heat shock protein 60 (HSP60), and mouse double minute 2 (MDM2) in human colorectal cancer progression using human cancer cDNA microarrays.

In this study, we applied commercially available cDNA microarray systems (1068 genes) to investigate the genetic changes in six colorectal cancers (CRC). Thirty-two genes fell into the group of commonly upregulated genes. In addition, we immunohistochemically investigated the expression of the four top ranked upregulated genes, Janus kinase 3 (JAK3), matrix metalloproteinase 13 (MMP13), heat shock protein 60 (HSP60), and mouse double minute 2 (MDM2), in 44 CRC. JAK3 staining was located in the cancer cells. A comparison of JAK3 immunostaining and clinicopathological parameters showed a significant association of tumor differentiation, pT, and TMN stage. Staining of MMP13 and HSP60 was noted mainly in the cytoplasm of cancer cells. A significant association of these expressions was observed with tumor differentiation and pT. MDM2 staining was noted in the nucleus of cancer and non-cancer cells. No significant association of clinicopathological parameters with MDM2 expression was observed. In multivariate analysis, JAK3 immunoreactivity showed independent prognostically unfavorable predictors. These data suggest that JAK3, in particular, is a highly significant, prognostic immunohistochemical marker in CRC. This study proves that cDNA microarrays, plotted by a small number of genes from a few samples, are both practical and useful.

Adenoma↗
PubMed2005

MRI evaluation of the uterine structure after myomectomy.

Myomectomy is a good indication for women with uterine leiomyoma who desire to preserve their child-bearing potential. However, there are still no reports about how long it takes the uterus to reach a stable state after myomectomy. We evaluated the changes in uterine structure during the recovery process after myomectomy by MR images. MR images were used to analyze the time-dependent changes in the length of the uterine cavity, the volume of the uterus, recovery of the junctional zone, prevalence of modification of the endometrium, and uterine structure in the region of the enucleated myoma. The cavity length and the volume of the uterus, and the myometrium were stabilized at six weeks after the myomectomy. With regard to the endometrium, 12 weeks were required for it to achieve a stable state after myomectomy. However, even at 12 weeks postoperatively, 14.2% of the cases showed an unusual view near the uterine incision on MR images. We concluded that the recovery process is complete at 12 weeks after the operation if there are no clear findings of hematoma or edema formation in the myometrium on MR images.

Adult↗
PubMed2005

Influence of ovarian cystectomy on the ovulatory function of the residual ovary.

BACKGROUND: Whether the surgery for benign ovarian disease affect ovulatory function on residual ovarian tissue has not yet been established. METHODS: We investigated the post-operative function of residual ovaries in 62 patients who underwent laparoscopic ovarian cystectomy or abdominal ovarian cystectomy. RESULTS: The results based on an average of 7.9 monitored ovulatory cycles after surgery showed that 53% of patients did not have natural ovulation from the diseased ovary. The number of developing follicles after ovulation-induction treatments was significantly less in the diseased ovary than in the healthy ovary. However, in 13 of 24 women who became pregnant after surgery, ovulation occurred in the diseased ovary. Although a reduction in maturation of follicles was suggested after cystectomy, some women became pregnant after ovulation from the diseased ovary. CONCLUSION: Our results suggest that careful attention should be given to preventing post-operative adhesion in the diseased and surgically managed ovary in cases that undergo cystectomy.

Adult↗