Conversion of gastric mucosa to intestinal metaplasia in Cdx2-expressing transgenic mice

Gastric intestinal metaplasia occurs as a pathological condition in the gastric mucosa. To clarify how an intestine-specific homeobox gene, Cdx2, affects the morphogenesis of gastric mucosa, we generated transgenic mice expressing Cdx2 in parietal cells. Until Day 18 after birth, the number of parietal cells inthegastric mucosa of transgenic mice was the same as for their normal littermates. However, at Day 19, we detected several glands in which parietal cells disappeared and the proliferating zone moved from the isthmus to the base of the glands. Thereafter, parietal cells decreased gradually and disappeared at Day 37. All of the gastric mucosal cells, except for enterochromaffin-like (ECL) cells, were completely replaced by intestinal metaplasia, consisting of goblet cells, enteroendocrine cells, and absorptive cells expressing alkaline phosphatase. Pseudopyloric gland metaplasia was also formed. The transgenic mouse is a very useful model for clarifying physiological differentiation of gastric and intestinal cell lineages and analyzing the molecular events from intestinal metaplasia to adenocarcinoma.

Aberrant expression of CDX2 in Barrett's epithelium and inflammatory esophageal mucosa

BACKGROUND

There have been no detailed reports directly comparing the expression of CDX1 with that of CDX2 in the inflammatory esophageal mucosa and Barrett's epithelium. The present study was designed to examine the expression of CDX 1/2 in inflammatory esophageal mucosa with or without Barrett's epithelium.

METHODS

The expression of CDX1/2 genes was analyzed using the reverse transcriptase-polymerase chain reaction (RT-PCR) in 34 human esophageal biopsy specimens, and CDX2 expression was also evaluated immunohistochemically, using anti-human CDX2 monoclonal antibody. The biopsy specimens for RNA extraction were taken endoscopically from esophageal mucosa with mucosal break due to gastroesophageal reflux disease (GERD), Barrett's epithelium, and normal epithelium. The expressions of mucin markers (MUC2) and intestine-specific genes (sucrase-isomal-tase, human defensin-5, alkaline phosphatase) were also comparatively analyzed.

RESULTS

CDX1/2 expression was not found in the normal esophageal mucosa. The prevalence of CDX1/2 mRNA expression was significantly higher in the mucosa with Barrett's epithelium than in the mucosa without Barrett's epithelium. It is noteworthy, however, that the CDX2 mRNA expression was initiated at the stage of esophagitis, when neither CDX1 nor intestine-specific genes had emerged yet. In contrast to CDX2, CDX1 was expressed only in Barrett's epithelium. Immunohistochemical study demonstrated strong and extensive nuclear immunoreactivity for CDX2 in Barrett's epithelium. Furthermore, fine granular cytoplasmic staining was also observed in the cytoplasm in Barrett's epithelium, as well as in inflammatory esophageal mucosa.

CONCLUSIONS

We report here, for the first time, that CDX2 is expressed in patients with Barrett's epithelium and inflammatory esophageal mucosa. These findings imply that the expression of CDX2 may be an early event leading to the development of Barrett's esophagus.

Aluminum-induced 1-->3-beta-D-glucan inhibits cell-to-cell trafficking of molecules through plasmodesmata. A new mechanism of aluminum toxicity in plants

Symplastic intercellular transport in plants is achieved by plasmodesmata (PD). These cytoplasmic channels are well known to interconnect plant cells to facilitate intercellular movement of water, nutrients, and signaling molecules including hormones. However, it is not known whether Al may affect this cell-to-cell transport process, which is a critical feature for roots as organs of nutrient/water uptake. We have microinjected the dye lucifer yellow carbohydrazide into peripheral root cells of an Al-sensitive wheat (Triticum aestivum cv Scout 66) either before or after Al treatment and followed the cell-to-cell dye-coupling through PD. Here we show that the Al-induced root growth inhibition is closely associated with the Al-induced blockage of cell-to-cell dye coupling. Immunofluorescence combined with immuno-electron microscopic techniques using monoclonal antibodies against 1-->3-beta-D-glucan (callose) revealed circumstantial evidence that Al-induced callose deposition at PD may responsible for this blockage of symplastic transport. Use of 2-deoxy-D-glucose, a callose synthesis inhibitor, allowed us to demonstrate that a reduction in callose particles correlated well with the improved dye-coupling and reduced root growth inhibition. While assessing the tissue specificity of this Al effect, comparable responses were obtained from the dye-coupling pattern in tobacco (Nicotiana tabacum) mesophyll cells. Analyses of the Al-induced expression of PD-associated proteins, such as calreticulin and unconventional myosin VIII, showed enhanced fluorescence and co-localizations with callose deposits. These results suggest that Al-signal mediated localized alterations to calcium homeostasis may drive callose formation and PD closure. Our data demonstrate that extracellular Al-induced callose deposition at PD could effectively block symplastic transport and communication in higher plants.

Development of gastric carcinoma from intestinal metaplasia in Cdx2-transgenic mice

In the progression of chronic gastritis, gastric mucosal cells deviate from the normal pathway of gastric differentiation to an intestinal phenotype. Many epidemiologic studies have found an association between the formation of intestinal metaplasia and the development of gastric carcinoma. However, there is no direct evidence that shows intestinal metaplasia is a precursor lesion of gastric carcinoma, to date. We periodically examined the intestinal metaplastic mucosa of Cdx2-transgenic mice we have previously generated. Gastric polyps developed from intestinal metaplastic mucosa in all stomachs of Cdx2-transgenic mice examined. These gastric polyps consisted of intestinal-type adenocarcinoma that invaded the submucosa and muscularis propria and occasionally spread into the subserosa. p53 and APC gene mutations were recognized in the adenocarcinomas. The participation of APC and p53 gene mutations in gastric carcinogenesis from the intestinal metaplasia was verified by the Cdx2-transgenic mice, carrying Apc(Min) mutation or p53 deficiency, that developed gastric polyps much earlier than Cdx2 alone. We successfully showed that long-term intestinal metaplasia induces invasive gastric carcinoma. These results indicate that intestinal metaplasia itself plays a significant role in the genesis and progression of gastric carcinoma.

Impaired production of gastric ghrelin in chronic gastritis associated with Helicobacter pylori

Ghrelin is primarily secreted from the stomach and has been implicated in the coordination of eating behavior and weight regulation. The effects of Helicobacter pylori infection on plasma ghrelin concentration and gastric ghrelin production still have not been well known. We determined plasma ghrelin concentration in a total of 160 consecutive individuals with normal body mass index including 110 H. pylori-infected and 50 H. pylori-negative subjects. The expression levels of ghrelin mRNA and ghrelin-producing cells in the gastric mucosa were quantified with real-time quantitative RT-PCR and immunohistochemistry, respectively. The severity of gastric atrophy was evaluated by serum pepsinogen concentrations. Plasma ghrelin concentration, gastric ghrelin mRNA, and ghrelin-positive cell numbers in gastric mucosa were significantly lower in H. pylori-infected subjects. The decrease in plasma ghrelin concentration in H. pylori-positive subjects was accompanied by an attenuation of ghrelin mRNA expression and a reduction of ghrelin-positive cell numbers in the gastric mucosa. Moreover, lower serum pepsinogen I concentrations and I/II ratio were significantly associated with lower plasma ghrelin concentrations in H. pylori-positive subjects. These findings suggest that impaired gastric ghrelin production in association with atrophic gastritis induced by H. pylori infection accounts for the decrease in plasma ghrelin concentration.

Expression of homeobox gene CDX2 precedes that of CDX1 during the progression of intestinal metaplasia

BACKGROUND

The CDX1 and CDX2 genes are intestinal transcription factors that may be involved in the regulation of proliferation and differentiation of intestinal epithelial cells. There have been no detailed reports directly comparing the expression of CDX1 with that of CDX2 in chronic gastritis and intestinal metaplasia. Accordingly, we examined the expression of CDX1/2 and its association with the expression of other intestinal metaplasia-associated genes during the development of intestinal metaplasia.

METHODS

The expression of CDX1/2 genes was analyzed, using the reverse transcriptase-polymerase chain reaction, in 44 human gastric tissue samples obtained endoscopically. The expressions of mucin markers (MUC2, MUC5AC), intestine-specific genes (sucrase-isomaltase, human defensin-5, alkaline phosphatase), a gene marker for fundic gland area (H+/K+ATPase beta subunit), and a gene for entire gastric glands (pepsinogen C) were also comparatively analyzed.

RESULTS

There was no expression of CDX1/2 in gastric mucosa not infected by Helicobacter pylori. The prevalence of CDX1 mRNA expression was significantly higher in mucosa with intestinal metaplasia than in mucosa without intestinal metaplasia. It is noteworthy that CDX2 was expressed in the antral and fundic mucosa in the absence of the expression of CDX1 and gene markers for intestinal metaplasia.

CONCLUSIONS

The expression of CDX2 precedes those of CDX1, sucrase-isomaltase, other intestine-specific genes (human defensin-5, alkaline phosphatase), and MUC2 during the progression of intestinal metaplasia. These findings imply that the expression of CDX2 may trigger the initiation and development of intestinal metaplasia.

Endoscopic submucosal dissection for superficial duodenal neoplasms

Endoscopic submucosal dissection (ESD) has emerged as a novel technique for achieving en bloc resection for superficial neoplasms limited to the mucosa. ESD was originally developed in Japan as a method of endoscopic resection of superficial gastric cancers. In our hospital, ESD has been used concurrently in other parts of the gastrointestinal tract, including the esophagus and colorectum from the beginning of its development. However, ESD in the duodenum is considered more challenging than other parts. From August 2005 to March 2008, a total of 15 superficial duodenal neoplastic lesions in 14 patients were treated with endoscopic resection. Of these, nine underwent ESD. We report our experience with duodenal ESD with a combination of ST hood and hook knife.

Cdx1 induced intestinal metaplasia in the transgenic mouse stomach: comparative study with Cdx2 transgenic mice

BACKGROUND AND AIMS

Gastric intestinal metaplasia, which is mainly induced by Helicobacter pylori infection, is thought to be a precancerous lesion of gastric adenocarcinoma. Intestinal metaplastic mucosa expresses intestine specific homeobox genes, Cdx1 and Cdx2, in the human gastric mucosa. We and others have reported that ectopic expression of Cdx2 in the gastric epithelium generates intestinal metaplasia in the transgenic mouse model.

METHODS

To clarify the differences in the roles of Cdx1 and Cdx2 in intestinal metaplasia, we generated transgenic mice expressing Cdx1 in the gastric mucosa and compared Cdx1 induced gastric mucosal morphological changes with Cdx2 induced intestinal metaplasia.

RESULTS

The gastric mucosa in Cdx1 transgenic mice was completely replaced by intestinal metaplastic mucosa, consisting of all four intestinal epithelial cell types: absorptive enterocytes, goblet, enteroendocrine, and Paneth cells. Paneth cells, which were not recognised in Cdx2 transgenic mice, were in the upper portion of the intestinal metaplastic mucosa. Pseudopyloric gland metaplasia, which was induced in Cdx2 transgenic mice, was not recognised in Cdx1 transgenic mice. Proliferating cell nuclear antigen (PCNA) positive cells were diffusely scattered in Cdx1 induced intestinal metaplastic mucosa while PCNA positive cells in Cdx2 induced intestinal metaplastic mucosa were in the base of the metaplastic mucosa. Intestinal metaplastic mucosa of Cdx1 transgenic mouse stomach was significantly thicker than that of wild-type or Cdx2 transgenic mouse stomach.

CONCLUSIONS

We have confirmed that Cdx1 induced gastric intestinal metaplasia but that it differed from Cdx2 induced intestinal metaplasia in differentiation, structure, and proliferation.

Sonographic diagnosis of fatty liver using a histogram technique that compares liver and renal cortical echo amplitudes

Accurate diagnosis of fatty liver using ultrasonography was attempted based on the difference between the echo intensities of the liver and kidney determined from ultrasonic histograms. Livers were then classified as having fatty infiltration, normal histology, or intermediate histology based on CT ratios established previously in earlier work comparing non-contrast-enhanced liver and spleen. The hepatorenal difference was significantly greater in the fatty liver group than in the normal liver group (8.9 +/- 2.0 dB vs 2.5 +/- 4.5 dB, p < 0.001). When a hepatorenal difference of > or = 7.0 dB was taken as the criterion, this method had a sensitivity of 91.3%, a specificity of 83.8%, and an accuracy of 86.7% for the diagnosis of fatty liver. Thus, quantitative ultrasonic diagnosis of fatty liver can be performed using echo intensity histograms.

Present and future status of flexible spectral imaging color enhancement and blue laser imaging technology

The usefulness of flexible spectral imaging color enhancement (FICE) has been reported for evaluating the esophagus, stomach, and small and large intestine. Higher contrast is shown between cancer and the surrounding mucosa in the esophagus and stomach and may facilitate the detection of gastric cancers missed by white light imaging alone. The surface patterns of gastric mucosa are clearly visualized in non-malignant areas but are irregular and blurred in malignant areas, leading to clear demarcation. Capsule endoscopy with FICE detects angiodysplasia and erosions of the small intestine. The surface and vascular pattern with FICE is useful for the differential diagnosis of colorectal polyps. However, FICE remains somewhat poor at visualizing mucosal microvasculature on a tumor surface. Narrow-band imaging (NBI) is dark in observing whole gastric mucosa and poor at visualizing mucosal microstructure. Blue laser imaging (BLI) has the potential to resolve these limitations. Narrow-band laser light combined with white light shows irregular microvessels on both differentiated and undifferentiated gastric cancer similar to those using NBI. In addition, irregular surface patterns including minute white zones are clearly seen on the uneven surface of differentiated lesions, resulting in exclusion of undifferentiated lesions. Using both distant and close-up views, a high contrast between green intestinal metaplasia and brown gastric cancer may lead to early detection of gastric cancers and determination of a demarcation line. BLI produces high-contrast images in esophageal cancer with clear vision of intrapapillary capillary loops and also predicts the histopathological diagnosis and depth of invasion in colorectal neoplasms.

Differential association of HLA with three subtypes of type 1 diabetes: fulminant, slowly progressive and acute-onset

AIM/HYPOTHESIS

We sought to clarify similarities and differences in the contribution of HLA to genetic susceptibility to three subtypes of type 1 diabetes: acute-onset, fulminant and slowly progressive.

METHODS

We genotyped 545 Japanese patients with type 1 diabetes (338 acute-onset, 80 fulminant, 127 slowly progressive) and 396 control participants at HLA-DRB1, -DQB1, -A, -B and -C, and at 101 candidate single nucleotide polymorphisms (SNPs) in an 8.5 Mb region of the extended HLA.

RESULTS

DRB1*0405-DQB1*0401, DRB1*0802-DQB1*0302 and DRB1*0901-DQB1*0303 were associated with acute-onset type 1 diabetes, with the DRB1*0405-DQB1*0401/DRB1*0802-DQB1*0302 genotype achieving the highest odds ratio of 42.7. DRB1*1501-DQB1*0602 and DRB1*1502-DQB1*0601 were negatively associated with acute-onset type 1 diabetes. A similar tendency was observed for slowly progressive type 1 diabetes. In contrast, only DRB1*0405-DQB1*0401 was associated with fulminant type 1 diabetes, with the DRB1*0405-DQB1*0401/DRB1*0405-DQB1*0401 genotype showing the highest odds ratio of 11.2. DRB1*0802-DQB1*0302, DRB1*0405-DQB1*0401/DRB1*0802-DQB1*0302 and DRB1*1501-DQB1*0602 were not associated with fulminant type 1 diabetes. The association of class I alleles and a panel of SNPs in an extended HLA region with fulminant type 1 diabetes was also different from that seen for the acute-onset and slowly progressive forms. The presence of both one and two susceptible haplotypes conferred susceptibility to slowly progressive type 1 diabetes, whereas the presence of two susceptible haplotypes was required to confer susceptibility to acute-onset and fulminant type 1 diabetes.

CONCLUSIONS/INTERPRETATION

These data suggest that HLA associations with fulminant type 1 diabetes are qualitatively different from those with other subtypes of type 1 diabetes, whereas the HLA contribution to slowly progressive type 1 diabetes is qualitatively similar to, but quantitatively different from, that in acute-onset type 1 diabetes.

Analysis of the signaling pathway involved in the regulation of hexokinase II gene transcription by insulin

The hexokinases, by converting glucose to glucose 6-phosphate, help maintain the glucose concentration gradient that results in the movement of glucose into cells through the facilitative glucose transporters. Hexokinase II (HKII) is the major hexokinase isoform in skeletal muscle, heart, and adipose tissue. Insulin induces HKII gene transcription in L6 myotubes, and this, in turn, increases HKII mRNA and the rates of HKII protein synthesis and glucose phosphorylation in these cells. Inhibitors of distinct insulin signaling pathways were used to dissect the molecular mechanism by which HKII gene expression is induced by insulin in L6 myotubes. Treatment with wortmannin, an inhibitor of phosphatidylinositol 3-kinase (PI 3-kinase), or with rapamycin, an inhibitor of the pathway from the insulin receptor to p70/p85 ribosomal S6 protein kinase (p70(s6k)), prevented the induction of HKII mRNA by insulin. In contrast, treatment with PD98059, an inhibitor of mitogen-activated protein kinase activation, had no effect on insulin-induced HKII mRNA. In addition, rapamycin blocked the insulin-induced expression of an HKII promoter-chloramphenicol acetyltransferase fusion gene transiently transfected into L6 myotubes, whereas PD98059 had no such effect. These results suggest that a phosphatidylinositol 3-kinase/p70(s6k)-dependent pathway is required for regulation of HKII gene transcription by insulin and that the Ras-mitogen-activated protein kinase-dependent pathway is probably not involved.

Hepatitis C virus infection and membranoproliferative glomerulonephritis in Japan

The prevalence of hepatitis C virus (HCV) infection was determined in 146 adult patients with various types of glomerulonephritis and renal diseases monitored between 1990 and 1993. Serum HCV antibody (HCV Ab) was evaluated, and positive cases were tested for HCV RNA by polymerase chain reaction. HCV infection was present in 1 (1.7%) of 58 cases of immunoglobulin A nephropathy, 0 (0%) of 14 cases of lupus nephritis, 0 (0%) of 12 cases of minimal change nephrosis, and 0 (0%) of 28 cases of other renal diseases, which is similar to the 2% prevalence observed in healthy blood donors in Japan. In contrast, HCV Ab was observed in 2 (8.3%) of 24 cases of membranous nephropathy and 6 (60%) of 10 cases of membranoproliferative glomerulonephritis (MPGN) Type I. The prevalence of HCV infection in MPGN patients was significantly higher than the frequency of HCV infection observed in the other patients with renal diseases (P < 0.001). HCV RNA was present in all cases in which HCV Ab was present. The six patients with HCV-MPGN were similar to the four patients with idiopathic MPGN with respect to age, presence of nephrotic syndrome, and renal dysfunction, but had a higher incidence of liver dysfunction, cryoglobulinemia, rheumatoid factor, and hypocomplementemia (low C3). HCV infection is present in a large percentage of patients with MPGN in Japan and clinically may differ slightly from other cases of MPGN.

Expression of gelatinase A, tissue inhibitor of metalloproteinases-2, matrilysin, and trypsin(ogen) in lung neoplasms: an immunohistochemical study

Lung cancer is a heterogeneous tumor in terms of clinical and biological behavior, and its aggressiveness depends on its invasive and metastatic properties. Matrix metalloproteinases and serine proteinases are believed to play a crucial role in invasion and metastasis of malignant tumor cells. In the present study, the authors evaluated immunohistochemically the expression of gelatinase A; tissue inhibitor of metalloproteinases-2 (TIMP-2), an inhibitor of gelatinase A; matrilysin; and trypsin(ogen) in 67 lung tumors from a variety of histological types including 17 squamous cell carcinomas, 16 adenocarcinomas, 15 small cell carcinomas, and 12 carcinoids. Interestingly, normal bronchial, bronchiolar, and alveolar epithelial cells expressed gelatinase A, TIMP-2, matrilysin, and trypsin(ogen) at varying frequencies and intensities. Bronchial smooth muscle cells and cartilage cells expressed gelatinase A alone, whereas endothelial cells, fibroblasts, and macrophages expressed gelatinase A and TIMP-2. Gelatinase A was expressed at high levels in most lung tumors examined (47% to 80%). TIMP-2 was also expressed at high levels except in the small cell carcinomas, which showed TIMP-2 expression at a lower frequency (60%) compared with other types of lung tumors (80% to 100%). Although matrilysin was expressed by tumor cells of all the histological types at various frequencies (13% to 63%), its expression was most common in adenocarcinomas. Expression of trypsin(ogen) was observed almost exclusively in adenocarcinomas (56%); other types of lung tumors expressed trypsin(ogen) far less frequently (0% to 12%). The present results, taken together with those of previous studies, suggest that gelatinase A is associated with malignant behavior of all the types of lung tumors, whereas its activity may be controlled by the endogenous inhibitor TIMP-2. The aggressive clinical behavior of small cell carcinoma may be attributable, at least in part, to a loss of the inhibitory effect of TIMP-2, as a significant proportion of these tumors showed negative or low levels of TIMP-2 expression. Matrilysin and trypsin(ogen) expressions are unlikely to be correlated with the aggressiveness of lung tumors. The expression of trypsin (ogen) may rather reflect the differentiation of adenocarcinoma cells toward normal airway epithelial cells.

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

OBJECTIVE

Studies 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.

METHODS

Cases 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.

RESULTS

The 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).

CONCLUSION

NSAIDs 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.

Nucleotide sequence of mouse IL-2 receptor cDNA and its comparison with the human IL-2 receptor sequence

We have cloned cDNA encoding the mouse interleukin-2 (IL-2) receptor from a murine T cell line, CTLL using human IL-2 receptor cDNA as probe. COS 7 cells transfected with the cDNA expressed the antigen recognized by the monoclonal antibody against the murine IL-2 receptor. The cDNA identified 4 species of mRNA (4.5, 3.5, 2.2 and 1.5 kb) of the mouse IL-2 receptor in CTLL cells. Difference in the length of mRNA seems to be ascribed to the variable length of the 3' untranslated sequence. Total nucleotide sequence (approximately 1400 bp) of this cDNA was determined and compared with the human receptor. The nucleotide and amino acid sequences of the IL-2 receptor are 70% and 60%, respectively, homologous in average between the two species. The comparison has revealed several conserved regions localized to particular exons such as transmembrane and cytoplasmic portions, suggesting that these regions are important for receptor function and its regulation.

Reversible limbic encephalitis caused by ovarian teratoma

A 19-year-old woman developed memory loss followed by psychosis, coma, convulsion, and central hypoventilation requiring mechanical ventilation. MRI of the brain showed minimal changes, and SPECT imaging revealed a small region of increased uptake in the cortex. Intravenous acyclovir and high-dose corticosteroids were administered without any effect. An extensive work-up revealed an elevated serum alpha-fetoprotein (AFP) concentration and the presence of an ovarian tumor. Following resection of the tumor, an immature teratoma by pathology, the patient had significant recovery of her cognitive function with some psychotic sequela. Serum anti-neuronal antibody (anti-Hu) was negative both by immunohistochemistry and by Western blot analysis. A rare combination of paraneoplastic limbic encephalitis and brainstem encephalitis was the suspected diagnosis. Because the tumor contained a neuronal component, we propose an immunologic cross-reaction as the pathomechanism, but the lack of a specific antibody may suggest cell-mediated rather than globulin-mediated immunity.

Retroviral expression of the human IL-2 gene in a murine T cell line results in cell growth autonomy and tumorigenicity

In mature T lymphocytes (T cells) the regulated expression of the genes for interleukin-2 (IL-2) and its receptor (IL-2R) constitutes an essential part in controlling the cell growth. Evidence has been provided which suggests the involvement of an aberrant function of the IL-2 system in developing T cell neoplasms, particularly the adult T cell leukemia/lymphoma (ATL). As an approach to examine the extent of the IL-2 system contribution to T cell neoplasms, we created the experimental conditions wherein both IL-2 and IL-2R are expressed constitutively in a murine T cell line. We made use of a retroviral vector to infect an IL-2-dependent CTLL-2 line and lead to the expression of human IL-2. Here, we show that the virus-infected cells not only proliferate in vitro in the absence of exogenously supplied IL-2 under certain conditions, but also develop tumors (lymphomas) in nude and syngeneic mice.

Aberrant expression of CDX2 in the gastric mucosa with and without intestinal metaplasia: effect of eradication of Helicobacter pylori

BACKGROUND

The intestine-specific transcription factor CDX2 plays an important role in differentiation and maintenance of intestinal epithelial cells. Development and progression of intestinal metaplasia (IM) in the stomach is closely associated with Helicobacter pylori-gastritis. We investigated expression of CDX2 protein in the gastric mucosa with and without IM before and after eradication of H. pylori.

MATERIALS AND METHODS

The subjects comprised five normal controls and 29 H. pylori-positive patients (15 with antral IM and 14 without IM), who were followed for 12 months after eradication of H. pylori. Biopsies were taken from the greater curvatures of the antrum and middle body. Expression of CDX2 was evaluated immunohistochemically using anti-CDX2 antibody.

RESULTS

CDX2 expression was not found in controls. Strong nuclear staining was observed extensively in IM, but rarely in the gastric epithelium, except for the focal area in only four antral biopsies (three with and one without IM). Fine granular cytoplasmic staining was also observed in the perinuclear regions of IM and the gastric epithelial cells in half of the patients. In 13 of the 15 patients with IM, IM did not regress after eradication of H. pylori, and the extent of nuclear staining in IM did not change. The extent of cytoplasmic staining did not change either.

CONCLUSIONS

Our results indicate that CDX2 expression in the gastric mucosa is found in patients with chronic gastritis and is closely associated with IM. CDX2 expression in IM or the gastric epithelial cells did not disappear after eradication of H. pylori.

A comparison of conventional endoscopy, chromoendoscopy, and the optimal-band imaging system for the differentiation of neoplastic and non-neoplastic colonic polyps

BACKGROUND

The diagnostic accuracy of conventional endoscopy for small colonic polyps is not satisfactory. Optimal band imaging (OBI) enhances the contrast of the mucosal surface without the use of dye.

OBJECTIVE

To evaluate the diagnostic accuracy for the differentiation of neoplastic and non-neoplastic colorectal polyps by using magnified OBI colonoscopy.

DESIGN

An open prospective study.

SETTING

Jichi Medical University, Japan.

PATIENTS

A total of 133 colonoscopy cases.

MAIN OUTCOME MEASUREMENT

A comparative study of the overall accuracy, sensitivity, and specificity for the differentiation of neoplastic and non-neoplastic colorectal polyps < or =5 mm in size by capillary-pattern diagnosis by using conventional colonoscopy, capillary-pattern diagnosis in OBI, and pit-pattern diagnosis in chromoendoscopy with low magnification.

RESULTS

A total of 107 polyps, composed of 80 neoplastic and 27 non-neoplastic polyps, were evaluated. OBI clearly showed the capillary network of the surface mucosa of neoplastic polyps at low magnification, whereas the surface mucosa of non-neoplastic polyps showed up as a pale lesion. The capillary pattern in conventional colonoscopy had 74% accuracy, 71% sensitivity, and 81% specificity for neoplastic polyps. The accuracy and sensitivity were significantly lower than those that used the capillary pattern in OBI (accuracy 87% and sensitivity 93%) and the pit pattern in chromoendoscopy (accuracy 86% and sensitivity 90%). There were no significant differences in specificity (OBI 70% and chromoendoscopy 74%). The kappa analysis indicated good agreement in both OBI and chromoendoscopy.

CONCLUSIONS

Capillary-pattern diagnosis in OBI is superior to that in conventional endoscopy and is not significantly different from pit-pattern diagnosis for predicting the histology of small colorectal polyps.

Aluminum inhibits the H(+)-ATPase activity by permanently altering the plasma membrane surface potentials in squash roots

Although aluminum (AL) toxicity has been widely studied in monocotyledonous crop plants, the mechanism of Al impact on economically important dicotyledonous plants is poorly understood. Here, we report the spatial pattern of Al-induced root growth inhibition, which is closely associated with inhibition of H(+)-ATPase activity coupled with decreased surface negativity of plasma membrane (PM) vesicles isolated from apical 5-mm root segments of squash (Cucurbita pepo L. cv Tetsukabuto) plants. High-sensitivity growth measurements indicated that the central elongation zone, located 2 to 4 mm from the tip, was preferentially inhibited where high Al accumulation was found. The highest positive shifts (depolarization) in zeta potential of the isolated PM vesicles from 0- to 5-mm regions of Al-treated roots were corresponded to pronounced inhibition of H(+)-ATPase activity. The depolarization of PM vesicles isolated from Al-treated roots in response to added Al in vitro was less than that of control roots, suggesting, particularly in the first 5-mm root apex, a tight Al binding to PM target sites or irreversible alteration of PM properties upon Al treatment to intact plants. In line with these data, immunolocalization of H(+)-ATPase revealed decreases in tissue-specific H(+)-ATPase in the epidermal and cortex cells (2--3 mm from tip) following Al treatments. Our report provides the first circumstantial evidence for a zone-specific depolarization of PM surface potential coupled with inhibition of H(+)-ATPase activity. These effects may indicate a direct Al interaction with H(+)-ATPase from the cytoplasmic side of the PM.

The interleukin-2 receptor, its physiology and a new approach to a selective immunosuppressive therapy by anti-interleukin-2 receptor monoclonal antibodies

In this report we have summarized our findings on the IL-2 receptor and our attempts to find an IL-2 receptor targeted immunosuppressive therapy. IL-2 receptors are detectable in two different forms: as monomeric, surface expressed, and as dimeric, presumably non-surface expressed molecules. The dimeric form seems to be non-covalently bound to an as yet undefined 110 KD molecule. The functions of the monomeric versus the dimeric form, as well as that of the noncovalently bound molecule, and their relationship to high and low affinity IL-2 receptors are not yet clear and remain to be elucidated. Upon antigenic or mitogenic stimulation, IL-2 receptors became expressed at the surface of T-lymphocytes. Receptor expression is accompanied by the capacity of the cells to proliferate in response to IL-2. Resting T-cells do not proliferate in response to IL-2. IL-2 dependent proliferation of cells without external stimulation is either due to the presence of a small number of IL-2 receptor bearing cells in the respective population or due to a small number of IL-2 receptors present on the surface of cells. IL-2 itself does not induce IL-2 receptor expression on resting cells but has been shown to up-regulate its own receptor once expressed. In contrast to resting lymphocytes, some leukemic cells and early embryonic thymocytes in the species tested constitutively express IL-2 receptors. The role of such constitutively expressed receptors is not yet clear. As demonstrated in mice, the requirement(s) for induction of IL-2 receptor expression for the helper/inducer subset (Lyt-2+) are different from those of the cytotoxic/suppressor subset (L3T4+). In contrast to Lyt-2+ cells, the accessory cell requirement for L3T4+ cells could not be replaced by cytokines. Whether Lyt-2+ cells require an additional, not yet defined receptor inducing factor (RIF) besides IL-2 in order to become IL-2 receptor positive and to consequently proliferate in response to IL-2, is a matter of controversy. There is evidence that interleukin-1 and some functionally related factors produced by leukemic cells enhance expression and/or function of the IL-2 receptors. IL-2 receptors of the high and low affinity type expressed upon antigenic stimulation are cleared from the cell surface. As demonstrated in this report, the vast majority of them, probably those of low affinity type, are released from the cells continuously. The mechanism of their release and the possible immunoregulatory role of circulating receptors found in the serum of animals is not yet clear.(ABSTRACT TRUNCATED AT 400 WORDS)

Autocrine loop between TGF-beta1 and IL-1beta through Smad3- and ERK-dependent pathways in rat pancreatic stellate cells

Pancreatic stellate cells (PSCs) are activated during pancreatitis and promote pancreatic fibrosis by producing and secreting ECMs such as collagen and fibronectin. IL-1beta has been assumed to participate in pancreatic fibrosis by activating PSCs. Activated PSCs secrete various cytokines that regulate PSC function. In this study, we have examined IL-1beta secretion from culture-activated PSCs as well as its regulatory mechanism. RT-PCR and ELISA have demonstrated that PSCs express IL-1beta mRNA and secrete IL-1beta peptide. Inhibition of TGF-beta(1) activity secreted from PSCs by TGF-beta(1)-neutralizing antibody attenuated IL-1beta secretion from PSCs. Exogenous TGF-beta(1) increased IL-1beta expression and secretion by PSCs in a dose-dependent manner. Adenovirus-mediated expression of dominant-negative (dn)Smad2/3 expression reduced both basal and TGF-beta(1)-stimulated IL-1beta expression and secretion by PSCs. Coexpression of Smad3 with dnSmad2/3 restored IL-1beta expression and secretion by PSCs, which were attenuated by dnSmad2/3 expression. In contrast, coexpression of Smad2 with dnSmad2/3 did not alter them. Furthermore, inhibition of IL-1beta activity secreted from PSCs by IL-1beta-neutralizing antibody attenuated TGF-beta(1) secretion from PSCs. Exogenous IL-1beta enhanced TGF-beta(1) expression and secretion by PSCs. IL-1beta activated ERK, and PD-98059, a MEK1 inhibitor, blocked IL-1beta enhancement of TGF-beta(1) expression and secretion by PSCs. We propose that an autocrine loop exists between TGF-beta(1) and IL-1beta in activated PSCs through Smad3- and ERK-dependent pathways.

Optimal band imaging system can facilitate detection of changes in depressed-type early gastric cancer

BACKGROUND

The endoscopic diagnosis of depressed-type early gastric cancers is difficult because these cancers manifest as subtle changes in color and shape. The newly developed optimal band imaging (OBI) system can reconstruct the best spectral images derived from ordinary endoscopic images and enhances the mucosal surface without the use of dyes. This imaging technique is based on narrowing the bandwidth of conventional image arithmetically by using spectral estimation technology.

OBJECTIVE

Evaluation of the usefulness of the OBI system for identifying the demarcation line of depressed-type early gastric cancers.

DESIGN

Prospective study.

SETTING

Jichi Medical University in Japan.

PATIENTS

Twenty-seven cases with depressed-type early gastric cancer.

MAIN OUTCOME MEASUREMENT

Comparative study for the success rate of identifying the demarcation line of depressed-type early gastric cancer by using optimal band images and conventional endoscopic images.

RESULTS

Demarcation of the depressed-type early gastric cancer was easily identified by optimal band images without magnification in 26 of 27 cases (96%), because distinct demarcation was observed endoscopically between the reddish images of the cancerous lesion and the yellowish images of the surrounding noncancerous area. With 40-fold magnification of optimal band images, the demarcation was also clearly recognized in all cases. Medical students could point out the demarcation line with significantly greater accuracy by observing the new nonmagnified optimal band images than by the conventional images (P< .0001).

LIMITATION

Small sample size.

CONCLUSIONS

The new contrasting images of the OBI system can delineate the depressed-type early gastric cancer more easily than conventional endoscopy.

Possible involvement of protein phosphorylation in aluminum-responsive malate efflux from wheat root apex

In many plants, efflux of organic anions from roots has been proposed as one of the major Al resistance mechanisms. However it remains unknown how plants regulate efflux of organic anions in response to Al. In this study, the regulatory mechanisms of Al-responsive malate efflux in wheat (Triticum aestivum) were characterized focusing on the role of protein phosphorylation. Al-resistant wheat (cv Atlas) initiated malate efflux at 5 min after addition of Al, and this response was sensitive to temperature. K-252a, a broad range inhibitor of protein kinases, effectively blocked the Al-induced malate efflux accompanied with an increased accumulation of Al and intensified Al-induced root growth inhibition. A transient activation of a 48-kD protein kinase and an irreversible repression of a 42-kD protein kinase were observed preceding the initiation of malate efflux, and these changes were canceled by K-252a. Malate efflux was accompanied with a rapid decrease in the contents of organic anions in the root apex, such as citrate, succinate, and malate but with no change in the contents of inorganic anions such as chloride, nitrate, and phosphate. These results suggest that protein phosphorylation is involved in the Al-responsive malate efflux in the wheat root apex and that the organic anion-specific channel might be a terminal target that responds to Al signaling mediated by phosphorylation.