Yuji Mizokami

Case-control study on the association of upper gastrointestinal bleeding and nonsteroidal anti-inflammatory drugs in Japan.

ObjectiveStudies in Western populations have shown the association of nonsteroidal anti-inflammatory drugs (NSAIDs) and upper gastrointestinal bleeding (UGIB). The role of Helicobacter pylori infection in NSAIDs-related UGIB remains to be studied. We conducted a case-control study in Japan to investigate these related topics.MethodsCases of UGIB due to duodenal or gastric ulcer, or gastritis were identified in 14 study hospitals in various areas of Japan. For each case, two controls were identified from population registries in the same district. Information on drugs and other risk factors was obtained from 175 cases and 347 controls by telephone interviews. Anti-H. pylori antibody in the urine was measured in a single laboratory for all the cases and 225 controls.ResultsThe odds ratio (OR) of UGIB was 5.5 for aspirin and 6.1 for other NSAIDs (NANSAIDs) (p<0.01). The OR for regular use was higher than for occasional use both for aspirin (7.7 vs 2.0) and NANSAIDs (7.3 vs 4.1). Loxoprofen (5.9), frequently used in Japan as a safe ‘prodrug’, was significantly associated with UGIB. The odds ratio for H. pylori infection was 4.9 and the relative excess risk due to the interaction between H. pylori and the use of NSAID was 1.2 (95% CI: −5.8–8.1).ConclusionNSAIDs including loxoprofen increase the risk of UGIB in Japan as in Western countries, with a similar magnitude of association. There was no evidence of biological interaction between NSAIDs and H. pylori infection.

Newly Developed Antibiotic Combination Therapy for Ulcerative Colitis: A Double-Blind Placebo-Controlled Multicenter Trial

OBJECTIVES:Fusobacterium varium may contribute to ulcerative colitis (UC). We conducted a double-blind placebo-controlled multicenter trial to determine whether antibiotic combination therapy induces and/or maintains remission of active UC.METHODS:Patients with chronic mild-to-severe relapsing UC were randomly assigned to oral amoxicillin 1500u2009mg/day, tetracycline 1500u2009mg/day, and metronidazole 750u2009mg/day, vs. placebo, for 2 weeks, and then followed up. The primary study end point was clinical response (Mayo score at 3 months after treatment completion) and secondary end points were clinical and endoscopic score improvements at 12 months. Anti-F. varium antibodies were measured by enzyme-linked immunosorbent assay.RESULTS:Treatment and placebo groups each had 105 subjects. At the primary end point, response rates were significantly greater with antibiotics than with placebo (44.8 vs. 22.8%, P=0.0011). Endoscopic scores significantly improved at 3 months (P=0.002 vs. placebo). Remission rates were 19.0% (antibiotics) vs. 15.8% (placebo) at 3 months (P=0.59). At the secondary end point, response rates were significantly greater with antibiotics than with placebo (49.5 vs. 21.8%, respectively, P<0.0001). Endoscopic scores were significantly improved at 12 months after antibiotic treatment (P=0.002 vs. placebo). Remission rates had improved to 26.7% with antibiotics vs. 14.9% for placebo, at 12 months (P=0.041). F. varium antibody titers decreased in responders but not in nonresponders, and more in the antibiotic than in the placebo group. More pretreatment steroid-dependent UC patients discontinued corticosteroids after treatment completion (6 months: 28.6 vs. 11.8%, respectively, P=0.046; 9 months: 34.7 vs. 13.7%, respectively, P=0.019; and 12 months: 34.7 vs. 13.7%, respectively, P=0.019). These effects were greater in the subanalysis of the active group (Mayo scores of 6–12) than in that of total cases (0–12). No serious drug-related toxicities occurred.CONCLUSIONS:The 2-week triple antibiotic therapy produced improvement, remission, and steroid withdrawal in active UC more effectively than a placebo.

Nuclear accumulation of beta-catenin in intestinal-type gastric carcinoma: correlation with early tumor invasion

Abstract. Mutation of the adenomatous polyposis coli gene, which is known to be an early event in the carcinogenesis of intestinal-type gastric carcinoma, leads to accumulation of beta-catenin. In addition, beta-catenin has been found to activate down stream signaling molecules in the wingless/Wnt pathway. In this study, the clinical significance of nuclear accumulation of beta-catenin was evaluated in gastric carcinoma. Immunohistochemical staining showed nuclear localization in 16 (12%) of 139 (94 intestinal-type and 45 diffuse-type) gastric carcinomas, and all 16 lesions with nuclear staining were intestinal-type adenocarcinomas. Of the 16 cases, 15 were in the early clinical stage. In the remaining case, the lesion had invaded the subserosal layer and showed strong nuclear staining at the invasive front. In 14 of the 16 cases with nuclear localization, there were no abnormal mobility shifts detected using polymerase chain reaction-single strand conformational polymorphism analysis. This was confirmed using direct sequencing analysis, which revealed the wild-type sequence in the 12 cases tested. Nuclear accumulation of beta-catenin did not correlate with lymph node metastasis or 5-year survival. These findings suggest that high intranuclear levels of beta-catenin protein play an important role in early tumor growth and may function in initiation of invasive processes in intestinal-type gastric carcinoma.

Involvement of Arp2/3 complex in the process of colorectal carcinogenesis

Increased motility is one of the characteristics of cancer cells, and actin polymerization and disassembly are essential for cellular motility. Since actin-related protein (Arp) 2/3 complex acts as a nucleus for actin polymerization, in this study, we immunohistochemically investigated the expression of Arp2 and Arp3 in 175 colorectal tumors in various stages of neoplastic progression. Arp2 and Arp3 showed identical expression patterns, and both were expressed in the stromal cells around neoplastic tubules or glands and in the tumor cells themselves. The frequency of expression of Arp2 and Arp3 (Arp2&3) by the stromal cells increased with the atypia of the colorectal neoplasms, from 5.5% (3/55) in adenoma with mild or moderate atypia, to 11.8% (2/17) in adenoma with severe atypia, 53.3% (16/30) in intramucosal carcinoma, and 91.8% (67/73) in invasive carcinoma (P<0.0001). The frequency of expression of Arp2&3 in the tumor cells was similar and was 1.8% (1/55) in adenoma with mild or moderate atypia, 23.5% (4/17) in adenoma with severe atypia, 23.5% (7/30) in intramucosal carcinoma, and 32.9% (24/73) in invasive carcinoma. Expression of Arp2&3 by the stromal cells was significantly correlated with nuclear accumulation of p53 in the tumor cells and stromal expression of CD10. These results suggest that formation of Arp2/3 complex by both neoplastic and stromal cells contributes to the increased motility of both cell types and thus provides suitable conditions for invasion.

Tumor-detecting capacity and clinical usefulness of SPIO-MRI in patients with hepatocellular carcinoma

Abstract: The tumor-detecting capacity and clinical usefulness of superparamagnetic iron oxide (SPIO) magnetic resonance imaging (MRI) were examined in patients with hepatocellular carcinoma. The tumor detection rate of SPIO-MRI (64.5%) was comparable to those of dynamic computed tomography (CT) and plain MRI, but lower than that for Gd dynamic MRI (93.5%; P < 0.01%). A combination of Gd dynamic MRI and SPIO-MRI improved the detection rate; further, the tumor stage with respect to tumor blood-flow pattern was predicted by combining plain MRI with SPIO-MRI. This combination procedure may also be useful for selecting therapeutic strategies.

The effects of cyclooxygenase2-prostaglandinE2 pathway on Helicobacter pylori-induced urokinase-type plasminogen activator system in the gastric cancer cells.

Background:u2002 Urokinase‐type plasminogen activator (uPA) and its receptor (uPAR) play an important role in the destruction of the extracellular matrix and basement membrane. The induction of uPA and uPAR in the gastric cancer cells with H. pylori has been demonstrated previously. The involvement of COX‐2‐PGE2 pathway in the uPA system (uPA and uPAR) expression is unclear.

Involvement of Cyclooxygenase-2–Prostaglandin E2 Pathway in Interleukin-8 Production in Gastric Cancer Cells

Prostaglandin E2 (PGE2) is thought to play an important role in both inflammatory and anti-inflammatory effects. The effect of PGE2 on the proinflammatory chemokine interleukin-8 (IL-8) in the gastric epithelial cells has not been defined yet. A gastric cancer cell line (MKN45) and primary gastric fibroblasts were cocultured with Helicobacter pylori standard strain (NCTC11637). The expressions of IL-8 and cyclooxygenase 2 (COX-2) mRNA were examined by reverse transcription polymerase chain reaction (RT-PCR) amplification. The amount of IL-8 antigen secreted by the MKN45 cells and gastric fibroblasts was measured by enzyme-linked immunosorbent assay (ELISA). We examined the effects of H pylori stimulation on IL-8 and COX-2 expression levels and the effects of COX-2 inhibitor on H pylori-induced IL-8 production in the MKN45 cells and gastric fibroblasts. Furthermore, we examined the expressions of subtypes of PGE2 receptors, the effects of arachidonic acid and PGE2 on IL-8 production, and the effects of PGE2 on the total cellular cyclic adenosine monophosphate (cAMP) in MKN45 cells. MKN45 cells and gastric fibroblasts expressed IL-8 and COX-2 mRNA under stimulation with H pylori. The MKN45 cells produced IL-8 and PGE2 antigen into the culture medium with H pylori stimulation, and the production level of IL-8 and PGE2 antigen decreased significantly with COX-2 inhibitor pretreatment (concentration: 50 μM). On the other hand, the gastric fibroblasts strongly produced IL-8 antigen even in the unstimulated condition, and the amount of IL-8 antigen was not affected by H pylori stimulation and/or COX-2 inhibitor pretreatment. The MKN45 cells expressed IL-8 mRNA and released IL-8 antigen slightly, and the expression level of IL-8 mRNA and the amount of IL-8 antigen increased significantly with PGE2 treatment in a dose-dependent manner. PGE2-induced IL-8 production was inhibited by pretreatment with EP2 and EP4 antagonists. The MKN45 cells expressed EP2 and EP4 subtypes of PGE2 receptors, and these expression levels were not affected by H pylori stimulation or PGE2 treatment. The amount of IL-8 antigen increased slightly, but not significantly, with arachidonic acid treatment. PGE2 treatment for 15 minutes increased the total cellular cAMP in the MKN45 cells. These results suggest that the COX-2–PGE2 pathway may be involved in IL-8 production in gastric epithelial cells.

Highly sensitive assay of HMG-CoA reductase activity by LC-ESI-MS/MS

We have developed a new sensitive and specific nonradioisotope assay method to measure the activity of HMG-CoA reductase, the rate-controlling enzyme in the cholesterol biosynthetic pathway. This method was based upon a stable isotope dilution technique by liquid chromatography-tandem mass spectrometry using electrospray ionization in positive mode. Mevalonic acid, the product of HMG-CoA reductase, was converted to mevalonolactone (MVL) in an incubation mixture, extracted by a salting-out procedure, derivatized into the mevalonyl-(2-pyrrolidin-1-yl-ethyl)-amide, and then purified using a disposable silica cartridge. The resulting mevalonylamide was quantified by selected reaction monitoring using the positive electrospray ionization mode. The detection limit of this mevalonylamide was found to be 240 amol (signal-to-noise ratio = 3), ∼833 times more sensitive than that of MVL measured by a conventional radioisotope (RI) method (200 fmol). The variances between sample preparations and between measurements by this method were analyzed by one-way layout and calculated to be 3.2% and 1.8%, respectively. The recovery experiments were performed using incubation mixtures spiked with 0.77–2.31 nmol MVL/mg protein and were validated by a polynomial equation. These results showed that the estimated concentration within a 95% confidence limit was 0.47 ± 0.07 nmol/mg protein, which coincided completely with the observed X̄0 nmol/mg protein with a mean recovery of 94.6%. This method made it possible to measure HMG-CoA reductase activity with a high degree of reproducibility and reliability, and especially with sensitivity superior to that of the conventional RI method.

Lung cancer with metastases to the stomach and duodenum. report of three cases

Over a period of about 1.5 years between September 1999 and April 2000, three cases of lung cancer that metastasized to the stomach and duodenum were encountered. Case 1 was a 74‐year‐old man with lung cancer at stage IV. During chemotherapy, he passed tarry feces, which led to an endoscopic examination. Subsequently, submucosal tumorous nodules were recognized in the stomach and descending portion of the duodenum, which were diagnosed as metastases. Case 2, a 59‐year‐old man, underwent radiotherapy for treatment of lung cancer at stage IV. He developed obstructive jaundice 15 months later and, following percutaneous drainage to correct the icteric condition, endoscopic examination was conducted. A 5‐cm submucosal tumor was found at the descending portion of the duodenum and a diagnosis of obstructive jaundice caused by a duodenal metastasis was given. Case 3, an 81‐year‐old male with stage IIIb lung cancer had been receiving oral Tegafur uracil. Because of hypochondriac pain that had lasted for 2 weeks, an endoscopic examination was conducted. A tumorous lesion was discovered in the horizontal part of the duodenum, which proved to be a metastasis. Metastasis of a lung cancer to the digestive system is rare: gastric metastasis is only 4.5% and metastasis to the small intestine, 5.8%. However, our experience suggests that metastases to the digestive system occur more frequently than reports would indicate. Endoscopic screening should be aggressively used, not only for those cases that develop subjective symptoms, but also for the asymptomatic cases to assess accuracy in staging, which may contribute to choosing the most appropriate therapeutic plan.

Liver abscess that developed after a long interval of transcatheter arterial embolization followed by formation of hepatoduodenal fistula

A 55‐year‐old male patient with hepatocellular carcinoma underwent transcatheter arterial embolization (TAE). He became febrile and experienced pain at the right hypochondrial region 323 days later, which led to the discovery of a liver abscess that fistulated into the duodenal bulb. There have been no reports on the fistulation of liver abscesses into the digestive system following TAE. Rhodococcus equi was isolated as a causative agent, which distinguished the case further.