Masayuki Tatemichi

Chemical basis of inflammation-induced carcinogenesis ☆

Chronic inflammation induced by biological, chemical, and physical factors has been associated with increased risk of human cancer at various sites. Inflammation activates a variety of inflammatory cells, which induce and activate several oxidant-generating enzymes such as NADPH oxidase, inducible nitric oxide synthase, myeloperoxidase, and eosinophil peroxidase. These enzymes produce high concentrations of diverse free radicals and oxidants including superoxide anion, nitric oxide, nitroxyl, nitrogen dioxide, hydrogen peroxide, hypochlorous acid, and hypobromous acid, which react with each other to generate other more potent reactive oxygen and nitrogen species such as peroxynitrite. These species can damage DNA, RNA, lipids, and proteins by nitration, oxidation, chlorination, and bromination reactions, leading to increased mutations and altered functions of enzymes and proteins (e.g., activation of oncogene products and/or inhibition of tumor-suppressor proteins) and thus contributing to the multistage carcinogenesis process. Appropriate treatment of inflammation should be explored further for chemoprevention of human cancers.

Induction of matrix metalloproteinase gene transcription by nitric oxide and mechanisms of MMP-1 gene induction in human melanoma cell lines.

Expression of 12 matrix metalloproteinases (MMPs) after exposure of human melanoma cell lines C32TG and Mewo to nitric oxide (NO) was investigated by the reverse transcription‐polymerase chain reaction. Expression of the mRNA of MMP‐1, ‐3, ‐10 and ‐13 in C32TG cells was transcriptionally enhanced in a dose‐dependent manner by exposure to an NO donor, S‐nitroso‐N‐acetyl‐DL‐penicillamine (SNAP) and mRNA expression of MMP‐1 and ‐10 was similarly enhanced in Mewo cells. Exposure of C32TG cells to NO increased the MMP‐1 protein concentration in the culture medium. Testing with the luciferase gene fused to the 1.5 Kbp 5′‐flanking region of the human MMP‐1 gene showed that exposure to NO upregulated MMP‐1 promoter activity in C32TG cells. Endogenous NO production after introduction of inducible NO synthase cDNA also enhanced MMP‐1 promoter activity in C32TG cells. Deletion and mutational analysis identified a critical AP‐1 binding site required for NO regulation of MMP‐1. A neighboring Ets motif from the AP‐1 site in the promoter region acted as an accessory to enhance MMP‐1 expression. Electromobility shift analysis using the AP‐1 binding site showed that NO enhanced the AP‐1 binding ability of nuclear factors in C32TG cells. PD98059, a selective MEK inhibitor and SB202190, a p38 MAPK inhibitor, attenuated the MMP‐1 mRNA expression enhanced by NO. Thus, MMP‐1 was transcriptionally enhanced by NO via MAPK (ERK and p38) pathways. The results of our study suggest that the increased expression of MMPs in response to NO may be associated with tumor progression under inflammation.

The out-patient management of patients with acute mild-to-moderate colonic diverticulitis

Background : There are no management criteria for optimum out‐patient care in mild‐to‐moderate acute colonic diverticulitis.

Enhanced expression of inducible nitric oxide synthase in chronic gastritis with intestinal metaplasia.

Nitric oxide produced by inducible nitric oxide synthase (iNOS) has been claimed to be involved in gastritis; however, its characteristics are largely unknown. We assessed (1) iNOS expression in the human gastric mucosa in chronic gastritis and (2) the cytokines associated with iNOS expression. Gastric biopsy specimens were obtained from patients with chronic gastritis. Total RNA was isolated and reverse transcription-polymerase chain reaction (PCR) was performed semiquantitatively using specific primer sets for iNOS, interleukin (IL)-1beta, IL-8, IL-6, interferon-y, tumor necrosis factor-alpha (TNF-alpha), TNF receptors, IL-6 receptors, and sucrase, respectively. Helicobacter pylori infection was examined by the PCR assay. Reverse transcription-PCR analysis showed that expression of iNOS was detected in 10 of 23 samples. Expression of iNOS mRNA was closely correlated with expression of TNF-alpha and was observed frequently in subjects with intestinal metaplasia. The Helicobacter pylori gene was detected by PCR assay in all iNOS-positive cases. These results indicate that iNOS is predominantly expressed in the gastric mucosa with intestinal metaplasia and H. pylori infection. TNF-alpha is thought to be an important cytokine associated with iNOS expression.

Increased risk of gastric cancer in Japanese subjects is associated with microsatellite polymorphisms in the heme oxygenase-1 and the inducible nitric oxide synthase gene promoters

Microsatellite polymorphism in the promoter region of the heme oxygenase-1 (HO-1) gene was analyzed jointly with that of the inducible nitric oxide synthase (iNOS) gene among Japanese subjects (control and gastric cancer patients). A higher promoter activity genotype of the HO-1 gene was associated with increased risk for gastric cancer in women. Gastric cancer risk was notably increased in subjects carrying a higher promoter activity genotype for both HO-1 and iNOS compared to those with a lower promoter activity genotype for both genes. Our data suggest that genetic polymorphisms of HO-1 and iNOS modulate individual susceptibility to gastric cancer risk.

Altered expression of a putative progenitor cell marker DCAMKL1 in the rat gastric mucosa in regeneration, metaplasia and dysplasia

BackgroundDoublecortin and calcium/calmodulin-dependent protein kinase-like-1 (DCAMKL1) is a candidate marker for progenitor cells in the gastrointestinal mucosa. Lineage cells in the gastric mucosa are derived from progenitor cells, but this process can be altered after injury. Therefore, we explored DCAMKL1 expression under pathological conditions.MethodsAn immunohistochemical analysis was performed in rat stomach with acute superficial injury, chronic ulcer, intestinal metaplasia and dysplasia.ResultsDCAMKL1 was exclusively expressed in immature quiescent cells in the isthmus of normal fundic glands, where putative progenitor cells are thought to reside. DCAMKL1-positive cells and proliferating cells shed into the lumen after superficial injury and re-appeared during the regenerative process, mainly in the superficial mucosa. In the marginal mucosa around the active ulcer, parietal and chief cells diminished, foveolar hyperplasia was evident, and trefoil factor family 2 (TFF2)/spasmolytic polypeptide-expressing metaplasia (SPEM) emerged at the gland base. DCAMKL1 cells re-emerged in the deep mucosa juxtaposed with SPEM and proliferating cells. In the healing ulcer, the TFF2 cell population expanded and seemed to redifferentiate to chief cells, while proliferating cells and DCAMKL1 cells appeared above and below the TFF2 cells to promote healing. SPEM appeared and PCNA cells increased in the intestinalized mucosa, and DCAMKL1 was expressed in the proximity of the PCNA cells in the deep mucosa. DCAMKL1, PCNA and TFF2 were expressed in different dysplastic cells lining dilated glands near SPEM.ConclusionThe ultrastructural appearance of DCAMKL1-positive cells and the expression patterns of DCAMKL1 in normal and pathological states indicate that the cells belong to a progenitor cell population. DCAMKL1 expression is closely associated with TFF2/SPEM cells after injury. DCAMKL1 cells repopulate close to proliferating, hyperplastic, metaplastic and dysplastic cells, and the progenitor zone shifts according to the pathological circumstances.

Clinical Significance of IgG Antibody Titer against Helicobacter pylori

Background: We clarified the clinical significance of measurement of IgG antibody titers against Helicobacter pylori using data from a nested case–control study from a large‐scale cohort study in Japan.

Laterality of the performance of glaucoma mass screening using frequency-doubling technology.

PurposeThis study investigated laterality during the performance of glaucoma mass screening with a frequency-doubling technology perimetry test. Materials and MethodsA frequency-doubling technology screening mode (C-20–1, version 2.6) test was performed on both eyes of 14,784 persons. Subjects with visual field abnormalities detected by the frequency-doubling technology test or with fixation error underwent retesting without a specified interval for rest. Consequently, 206 subjects who fulfilled the screening criteria of the frequency-doubling technology-based glaucoma screening protocol [FDT-GSP(+)] were further investigated using the Humphrey visual field analyzer (30–2). As a result, 74 right eyes and 57 left eyes were shown to have definite glaucoma. ResultsFrequency-doubling technology data for the left eye demonstrated a significantly (P <0.001) higher rate of artifacts, such as no reproducibility of results between the first and second tests (left/right: 2.4%/1.7%) as well as fixation errors (left/right: 2.8%/1.0%). The false-positive rate of the FDT-GSP for glaucoma was more than 1.5-fold higher in the left eye than in the right eye (16.3%/9.8%). In the case that either eye exhibited FDT-GSP(+), the positive predictive value of the FDT-GSP for definite glaucoma in the left eye was almost half of that in the right eye (28.4% vs. 53.8%). Specificity of the FDT-GSP for detection of definite glaucoma also exhibited a lower trend (P = 0.097) in the left eye (44.6%) than in the right eye (55.3%), but the sensitivity of the test was similar in both eyes (91.2% vs. 90.5%, respectively). ConclusionsWhen frequency-doubling technology-based mass screening is performed on the general population, performance is lower for the left eye than for the right eye. This performance disparity is likely to be primarily associated with a difference in specificity.

Ethnic difference in serology of Helicobacter pylori CagA between Japanese and non-Japanese Brazilians for non-cardia gastric cancer

The usefulness of serology against CagA of Helicobacter pylori as a biomarker to identify high‐risk individuals for non‐cardia gastric cancer (ncGC) remains unclear among several ethnic populations with a high prevalence of cagA‐positive strains. We investigated ethnic differences of CagA serology in two sets of case‐control subjects, Japanese‐Brazilians (JB) and non‐Japanese Brazilians (NJB). We performed a cross‐sectional comparison of IgG antibody titers to CagA (CagA‐Ab) and the combination of CagA‐Ab with conventional surface antigen (Hp‐Ab) in 80 JB and 178 NJB ncGC patients and their controls (160 JB and 178 NJB). The level of CagA‐Ab titer in cancer cases was significantly higher in NJB than in JB. The strength of the association between CagA‐Ab seropositivity (+) (>10 U/ml) and ncGC was almost 2‐fold higher in NJB than in JB [odds ratio (OR) (95% confidence interval), 4.5 (2.6–7.8) and 2.1 (1.2–3.6), respectively]. However, in both JB and NJB, the OR was highest in CagA‐Ab(+) subjects with low titer (10–29 U/ml), and decreased inversely with elevating CagA‐Ab titer. In addition, the serological status of CagA‐Ab(+) and Hp‐Ab(‐) showed a similar close association with ncGC between JB and NJB [5.4 (1.9–15.3) and 5.4 (2.0–15.0), respectively]. These results suggest that although the roles of CagA in the carcinogenic process of ncGC might be different between JB and NJB, the CagA‐Ab could be a useful marker for ncGC, independently of ethnicity, particularly in high‐risk individuals with the serological status of CagA‐Ab(+) with low IgG titer or combined with Hp‐Ab(‐). (Cancer Sci 2003; 94: 64–69)

In vivo visualization of lymphatic microvessels and lymphocyte migration through rat Peyer's patches

BACKGROUND/AIMS In the small intestine, lymphocytes migrate through Peyers patches. The distribution of lymphatic microvessels in rat Peyers patches and lymphocyte traffic through them were studied. METHODS Vital dyes were injected via a micropipette into the Peyers patches tissue to fill lymphatic microvessels and to stain lymphocytes in lymphatic microvessels. RESULTS Direct microscopic observation revealed a dense plexus of lymphatic microvessels in the perifollicular and interfollicular areas. Injection of the dyes into the germinal center failed to delineate lymphatic microvessels. The lymphatic microvessels in the perifollicular area were filled with lymphocytes. Most lymphocytes in the perifollicular lymphatics stayed in the lymphatic microvessels. Some lymphocytes became detached and drained into lymphatic microvessels in the interfollicular areas. Lymphocytes then moved toward the submucosal lymphatics beneath the villi around the Peyers patches. The interfollicular lymphatics did not display contractile activity but had valves. Opening and closing of valves was synchronized with the respiration and the back and forth flow of lymphocytes. CONCLUSIONS There are numerous lymphocytes in a dense lymphatic network in the perifollicular and interfollicular areas of Peyers patches. This well-developed lymphatic network has the potential capacity for storage of lymphocytes and modulation of lymphocyte migration.