Search

Background Cannabinoid (CB) receptor agonists are expected to alleviate ischemic brain damage by modulating neurotransmission and neuroinflammatory responses via CB1 and CB2 receptors, respectively. In a previous study, TAK-937, a novel potent and selective CB1 and CB2 receptor agonist, was shown to exert significant cerebroprotective effects accompanied by hypothermia after transient middle cerebral artery occlusion (MCAO) in rats. Sustained hypothermia itself induces significant neuroprotective effects. In the present studies, we examined the relative contribution of hypothermia and CB1 receptor activation to the cerebroprotective effects of TAK-937. Methodology/Principal Findings Using a multichannel brain temperature controlling system we developed, the brain temperature of freely moving rats was telemetrically monitored and maintained between 37 and 38°C during intravenous infusion of TAK-937 (100 µg/kg/h) or vehicle for 24 h after 2 h MCAO. AM251, a selective CB1 receptor antagonist, was administered intraperitoneally at 30 mg/kg 30 min before starting intravenous infusion of TAK-937 (100 µg/kg/h) for 24 h. Rats were sacrificed and their brains were isolated 26 h after MCAO in both experiments. When the hypothermic effect of TAK-937 was completely reversed by a brain temperature controlling system, the infarct-reducing effect of TAK-937 was attenuated in part, but remained significant. On the other hand, concomitant AM251 treatment with TAK-937 completely abolished the hypothermic and infarct-reducing effects of TAK-937. Conclusions/Significance We conclude that the cerebroprotective effects of TAK-937 were at least in part mediated by induction of hypothermia, and mainly mediated by CB1 receptor activation.

We have previously demonstrated that gastric and intestinal endocrine cell (End-cell) marker expression is important for assessment of the histogenesis of endocrine cell tumors. However, the End-cell phenotypes of carcinoid tumors in the rectum remain largely unclear. We therefore examined marker expression of rectal carcinoid tumors. We evaluated 20 rectal carcinoid tumors (as well as 8 from the stomach for comparison) phenotypically, using gastrin, gastric inhibitory polypeptide (GIP) and glucagons-like peptide-1 (GLP-1) as End-cell markers. Rectal carcinoid tumors were divided into 3 endocrine-gastric (e-G), 16 endocrine-gastric-and-intestinal mixed (e-GI), 1 endocrine-intestinal (e-I), and 0 endocrine-null (e-N) types, thus 19 (e-G+ e-GI types, 95%) had gastric phenotypic expression, while 17 (e-GI+ e-I types, 85%) harbored intestinal elements. Stomach carcinoid tumors were classified as 6 e-G and 2 e-N types, respectively. In conclusion, most rectal carcinoid tumors exhibited the e-GI type, suggesting the importance of gastric End-cell marker expression for histogenesis of the rectal carcinoid tumors. Further studies of pathological and biological analyses are needed to clarify the histogenesis of the carcinoid tumors.

An animal model for the early detection of common fatal diseases such as ischemic diseases and cancer is desirable for the development of new drugs and treatment strategies. Hypoxia-inducible factor 1 (HIF-1) is a transcription factor that regulates oxygen homeostasis and plays key roles in a number of diseases, including cancer. Here, we established transgenic (Tg) mice that carry HRE/ODD-luciferase (HOL) gene, which generates bioluminescence in an HIF-1-dependent manner and was successfully used in this study to monitor HIF-1 activity in ischemic tissues. To monitor carcinogenesis in vivo, we mated HOL mice with rasH2 Tg mice, which are highly sensitive to carcinogens and are used for short-term carcinogenicity assessments. After rasH2-HOL Tg mice were treated with N-methyl-N-nitrosourea, bioluminescence was detected noninvasively as early as 9 weeks in tissues that contained papillomas and malignant lesions. These results suggest that the Tg mouse lines we established hold significant potential for monitoring the early onset of both ischemia and carcinogenesis and that these lines will be useful for screening chemicals for carcinogenic potential.

Aberrant DNA methylation is deeply involved in carcinogenesis, and Helicobacter pylori infection, a Group-I carcinogen according to IARC classification, is known to induce aberrant methylation in gastric epithelial cells. Therefore, it is likely that methylation induction is the major mechanism by which H. pylori infection induces gastric cancers. In this study, using a Mongolian gerbil model, we aimed to clarify whether a DNA demethylating reagent, 5-aza-2′-deoxycytidine (5-aza-dC), can prevent H. pylori-induced gastric cancers. Administration of N-methyl-N-nitrosourea (20 p.p.m. by drinking water from 5 to 25 weeks of age) and H. pylori infection (∼108 CFU, at 5 weeks of age) induced gastric cancers in 55.2% of the gerbils at 55 weeks of age. By intraperitoneal infection of 5-aza-dC (0.125 mg/kg body weight, twice a week from 5 to 55 weeks of age), the incidence decreased significantly to 23.3% (P Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2002. doi:10.1158/1538-7445.AM2011-2002

Mouse tenascin (TN)-encoding cDNA clones were isolated from a cDNA library of the 2H6GR mammary tumor cell line. Nucleotide (nt) and deduced amino acid (aa) sequences revealed the characteristic primary structure, which begins with a signal peptide and TN unique sequences, follows with 14 case1 2 epidermal growth factor (EGF)-like repeats and 13 fibronectin type-III repeats (FN repeat), and concludes with fibrinogen-homologous sequences. Similar to chicken and human TN the mouse TN cDNA contains five consecutive insertional FN repeats, as well as eight constitutive FN repeats. Three different cDNA clones that may have been generated by alternative splicing of these insertional FN repeats were identified and characterized. Based upon the deduced aa sequence, a polyclonal antibody was produced against a synthetic TN peptide. It specifically recognized two TN isoforms of 230 kDa and 190 kDa in protein extracts of mouse tissues. The tissue distributions of mouse TN mRNAs, revealed by Northern blot analysis, suggest that there is tissue-specific expression of TN isoforms. Two distinct mRNA transcripts (7 kb and 5.5 kb) were detected in brain, skeletal muscle, digestive tract and bladder, but only one was observed in lung, kidney (7 kb) and thymus (5.5 kb). TN mRNA expression was down-regulated 1 month after birth in most tissues. However, the 5.5-kb transcript persisted in cerebellum, thymus, and colon. The spatial and temporal patterns of TN expression seem to be controlled at the level of transcription, because analysis of various tissues by Western blots showed the same pattern as that seen in Northern blots.

Three cases of the pleural effusion complicating radical neck dissection were reported and discussed.Radical neck dissection was performed on the left side neck and thoracic duct was injured intraoperatively in every 3 cases.In 2 cases, extra cellular Sudan III positive granules were found in pleural effusion. In 1 case, lymphangioscintigraphy showed accumulation of radio activity in the thoracic cavity.Therefore, pleural effusion seemed to be the accumulation of chyle or thoracic duct lymph.All 3 cases were healed by the conservative treatment without further complication.

We have previously suggested that an origin of a stomach cancer is from a progenitor cell specializing toward exocrine cell (Exo-cell) lineages. To clarify whether our hypothesis is correct or not, we analyzed the expression of Exo-cell and endocrine cell (End-cell) markers in a series of lesions for comparison. We evaluated chromogranin A (CgA) expression in 37 early and 73 advanced stomach cancers, in 30 stomach adenomas, in 8 carcinoid tumors, and in 4 endocrine cell carcinomas (ECCs) with assessment of gastric and/or intestinal (G/I) phenotypes in both Exo-cell and End-cell by immunohistochemistry. CgA expression was observed in 10.8% of the early and 16.4% of the advanced stomach cancers, respectively. The End-cell G/I phenotypes were in line with the Exo-cell counterparts in the CgA-positive stomach cancerous areas, and there was strong association between Cdx2 expression and the intestinal End-cell markers. All of the adenoma cases had the intestinal Exo-cell phenotypic expression, with the positive link between Exo-cell and End-cell G/I phenotypes. All stomach carcinoids had CgA expression but no expression of Exo-cell markers. In conclusion, most stomach cancers might develop from a progenitor cell specializing towards Exo-cell lineages, but some cases possessed both Exo-cell and End-cell markers with maturely differentiated phenotypes. In such cases, Exo-cell and End-cell phenotypes were found to correlate strongly, suggesting the possibility of histogenesis from “cancer stem cells”.

Background. The caudal-type homeobox genes, Cdx1 and Cdx2, are candidates for directing intestinal development, differentiation, and maintenance of the intestinal phenotype. The aims of this study were: (1) to assess the normal tissue expression patterns of Cdx1 and Cdx2 in the human gastrointestinal tract and (2) to ascertain levels in intestinal metaplasia (IM) of the stomach associated with gastritis. Methods. Fresh human tissues were collected by surgical resection from 39 patients after informed consent had been received. RNAs were extracted from 11 distinct sites in the gastrointestinal mucosa (gastric body, gastric antrum, duodenum, jejunum, ileum, cecum, ascending colon, transverse colon, descending colon, sigmoid colon, and rectum), and Northern hybridization was performed for Cdx1 and Cdx2 mRNAs. In addition, RNAs were also extracted from normal gastric mucosa, and gastric mucosa with mild to severe IM, confirmed histopathologically. Reverse-transcriptase polymerase chain reaction (RT-PCR) was then carried out for Cdx1 and Cdx2. Results. The expression of Cdx1 mRNA increased gradually from the duodenum to the distal colon, with no expression detected in the stomach. Compared with the distribution of Cdx1 mRNA in the mouse gastrointestinal tract, the expression of Cdx1 mRNA in the human gastrointestinal tract showed greater predominance in the jejunum and ileum. The expression of Cdx2 mRNA increased gradually from the duodenum to the proximal colon and decreased from the ascending colon to the rectum. Compared with the expression pattern of Cdx2 mRNA in the mouse gastrointestinal tract, the expression of Cdx2 mRNA in the human gastrointestinal tract showed greater predominance in the ileum. By RT-PCR, both Cdx1 and Cdx2 mRNAs were detected in the mild and severe types of IM. However, neither of these mRNAs was identified in normal gastric mucosa without IM. Conclusions. Cdx1 and Cdx2 mRNAs are widely present in the human intestinal and colonic mucosae, but not in the gastric mucosa, suggesting that their expression may contribute to the intestinal phenotype. The high levels of these mRNAs in IM mucosa associated with chronic atrophic gastritis point to an association with this phenotypic shift in the gastric mucosa.

Helicobacter pylori (Hp) is thought to be a stomach carcinogen from epidemiological findings. To determine the effects of infection with the bacteria on experimental carcinogenesis, a study of the glandular stomach of Mongolian gerbils (MGs) was performed. Male MGs were treated with N-methyl-N'-nitro-N-nitrosoguanidine followed by inoculation with Hp or infected with Hp followed by N-methyl-N'-nitro-N-nitrosoguanidine administration. Animals were killed at week 50, and their excised stomachs underwent microbiological and histopathological examinations. In addition, a serological investigation was performed. The incidences of adenocarcinomas were significantly higher in animals treated with 60 or 300 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine for 10 weeks followed by Hp inoculation or Hp followed by 20 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine for 30 weeks than in the respective controls. Moreover, tumour-bearing animals had higher titres of anti-Hp antibodies than tumour-free animals. Of interest was the finding that a dose of 100 p.p.m. N-methyl-N'-nitro-N-nitrosoguanidine given to infected gerbils eradicated the Hp in about half the animals, with a concomitant reduction in the promoting effect. No tumours were found in animals infected with Hp without N-methyl-N'-nitro-N-nitrosoguanidine or non-treated gerbils. Hp infection enhances glandular stomach carcinogenesis in MGs treated with N-methyl-N'-nitro-N-nitrosoguanidine. Animals with high titres of anti-Hp antibodies are at greatest risk of developing neoplasms.

Aims: The intake of salt and salty food is known as a risk factor for gastric cancer. We have previously demonstrated that a high-salt diet dosedependently enhances Helicobacter pylori (H. pylori)- associated gastritis and stomach carcinogenesis in Mongolian gerbils. In this study, we focused on the influence of excessive salt intake on the expression of inflammatory mediators involved in progression of H. pylori-induced chronic gastritis. Methods and Results: A total of 45 stomach samples from Mongolian gerbils were evaluated by immunohistochemistry. The animals were infected with H. pylori and fed basal (0.32%) or a high-salt (10%) diet, and sacrificed after 40 weeks. Proliferative activity and expression of cyclooxygenase-2 (COX-2) in gastric mucosa were significantly increased in H. pyloriinfected gerbils. The additional high-salt diet significantly up-regulated the expression of inducible nitric oxide synthase (iNOS) and COX-2 in H. pyloriinfected groups (P

Expression of cathepsin E in epithelial cells of the normal glandular stomach and small intestine, intestinal metaplasia, stomach and small intestinal tumors, was investigated in rats treated with N-methyl-N'-nitro-N-nitrosoguanidine (MNNG). Immunohistochemically, parietal cells were found to be moderately positive while surface mucous and pyloric gland cells demonstrated marked staining. Intestinal metaplastic glands in the stomach and normal small intestinal epithelial cells did not have any cathepsin E reactivity although some regenerative small intestinal epithelium proved positive. Histochemical staining for mucin demonstrated all stomach tumors (adenomatous hyperplasias and well-differentiated adenocarcinomas) to be mainly comprised of gastric epithelial type cells (pyloric gland and surface mucous cells), with intestinal epithelial type cells (goblet and intestinal absorptive cells) being only occasional findings. Almost all of the gastric epithelial type cells showed cathepsin E reactivity in their cytoplasm while the intestinal epithelial cell type cells were mainly consisted of cathepsin E negative one like those in small intestinal cancers. Catepsin E may thus be a useful marker for cell differentiation of stomach tumors and their intestinalization. Cancers arising in the small intestine consisted of intestinal epithelial cell type cells, but no stomach tumors consisted predominantly of this type, so that there was no suggestion of any derivation from intestinal metaplasias in rats.

The effects of D-galactosamine (D-gal) and carbon tetrachloride (CCl4) administration on induction of liver cell proliferation in a medium term liver bioassay for detection of initiation activity of 1,2-dimethylhydrazine (DMH) were investigated with special emphasis on kinetics of cell proliferation and cytochrome P450 (CYP) expression. In experiment I, fluctuation of cell proliferation and CYP 2E1, which is one of the enzymes involved in bioactivation DMH to ultimate form, levels of liver cells after D-gal administration (4000 mg/kg, i.g.) or CCl4 administration (1 ml/kg, i.g.) was analyzed by bromodeoxyuridine labeling and western blotting, respectively. In experiment II, induction of glutathione S-transferase placental form (GST-P)-positive foci by DMH in a model for detection of initiation activities using D-gal or CCl4 administration as a toxicity-regeneration dependent proliferative stimulus was evaluated. Although high BrdU labeling indices continued from 36 h to 72 h after D-gal and CCl4 treatment, cell proliferation after intragastric D-gal administration was very low compared with the CCl4 case. Decrease of CYP 2E1 apoprotein content in the microsomes was slight after D-gal administration, whereas decrease up to about 40% of the control level was evident from 12 h until 60 h after CCl4. When the carcinogen was injected 60 h after D-gal administration, there was appreciable increase in the area and numbers of GST-P positive foci, similar to the case with CCl4 administration. Sensitivities for detection of initiation activity with intragastric D-gal or CCl4 administration were equal, despite the kinetics of cell proliferation and CYP 2E1 being very different. With CCl4 administration, initiation depended on fluctuation of CYP 2E1, reversibly in intragastric D-gal treatment, initiation depended on cell kinetics.