Mesoterricola silvestris gen. nov., sp. nov., Mesoterricola sediminis sp. nov., Geothrix oryzae sp. nov., Geothrix edaphica sp. nov., Geothrix rubra sp. nov., and Geothrix limicola sp. nov., six novel members of Acidobacteriota isolated from soils

Forty-eight Acidobacteriota strains were isolated from soils and sediments in Japan. Among them, six representative strains, designated W79T, W786T, Red222T, Red802T, Red803T, and Red804T, were subjected to the taxonomic classification. These six strains are Gram-stain-negative, non-spore-forming, rod-shaped, and facultative anaerobic bacterium that can reduce ferric iron. Phylogenetic and phylogenomic trees based on 16S rRNA genes and multiple single-copy gene sequences showed that strains Red222T, Red802T, Red803T, and Red804T formed a cluster with the type strains of Geothrix species, but strains W79T and W786T created an independent cluster from any other type strains. The former four strains shared 97.95-99.08% similarities of 16S rRNA gene sequence with the type strains of the genus Geothrix, whereas the latter two strains 94.86-95.49% similarities. The average amino acid identity of strains W79T and W786T were <63 % to any other type strains, which were below the genus delineation thresholds. Moreover, colonies of these two strains were white, while those of the other four isolated strains were reddish-yellow as well as the type strain Geothrix fermentans H-5T. Although the known type strains of Geothrix species have been reported to be non-motile, five strains (W79T, W786T, Red222T, Red803T, and Red804T) except for strain Red802T displayed motility. Furthermore, multiple genomic, phylogenetic, and phenotypic features supported the discrimination between these isolated strains. Based on the study evidence, we propose these six isolates as novel members within the Acidobacteriota/Holophagae/Holophagales/Holophagaceae, comprising two novel species of a novel genus, Mesoterricola silvestris gen. nov., sp. nov., and Mesoterricola sediminis sp. nov., and four novel species of the genus Geothrix: Geothrix oryzae sp. nov., Geothrix edaphica sp. nov., Geothrix rubra sp. nov., and Geothrix limicola sp. nov.

Biological nitrogen fixation in the long-term nitrogen-fertilized and unfertilized paddy fields, with special reference to diazotrophic iron-reducing bacteria

Biological nitrogen fixation (BNF) is important to sustain nitrogen fertility of paddy soil and rice yield, while could be affected by nitrogen fertilization. Iron-reducing bacteria, Anaeromyxobacter and Geobacter, are newly found diazotrophic bacteria predominant in paddy soil. Experimental field of this study is a long-term (35 years) nitrogen fertilized (6.0 g N/m2/year) and unfertilized paddy field, where ca. 70% of rice yield was obtained yearly in nitrogen unfertilized plot (443 ± 37 g/m2) compared to fertilized plot (642 ± 64 g/m2). Effects of long-term nitrogen fertilization/unfertilization on soil properties related to BNF were investigated with special reference to diazotrophic iron-reducing bacteria. Soil chemical/biochemical properties, soil nitrogen-fixing activity, and community composition of diazotrophic bacteria were similar between nitrogen fertilized and unfertilized plot soils. In both plot soils, Anaeromyxobacter and Geobacter were the most predominant diazotrophs. Their nifD transcripts were detected at similar level, while those of other general diazotrophs were under detection limit. It was concluded that long-term use/unuse of nitrogen fertilizer in this field did not affect the predominance and nitrogen-fixing activity of diazotrophic iron-reducing bacteria, composition of other general diazotrophs, and the resulting soil nitrogen-fixing activity. BNF, primarily driven by diazotrophic iron-reducing bacteria, might significantly contribute to sustain soil nitrogen fertility and rice yield in both plot soils. Appropriate soil management to maintain BNF, including diazotrophic iron-reducing bacteria, will be important for sustainable soil nitrogen fertility and rice production.

N2O emission factors for organic amendments in Japan from measurement campaign and systematic review

Organic amendments are important sources of nitrous oxide (N₂O) emissions from agricultural soils. In 2020, the total amount of N in organic amendments applied to Japanese agricultural soils (440 ktN) was larger than that of synthetic fertilizer (374 ktN). However, N₂O emissions from organic amendments were estimated by using the country-specific N₂O emission factor (EF) for synthetic fertilizer (0.31 % for rice paddy, 2.9 % for tea, and 0.62 % for other crops) in the National Greenhouse Gas Inventory Report of Japan. Thus, we conducted a N₂O flux measurement campaign at 12 different experimental sites across Japan to estimate fertilizer-induced N₂O EFs for major organic amendments in Japan, that is, poultry manure compost, swine manure compost, cattle manure compost, and organic fertilizer pellets. In addition, we conducted systematic review of N₂O emissions and EFs for organic amendments, including data from our measurement campaign and published data from peer-reviewed papers in Japan. The final dataset, including the field measurement campaign and published data, resulted in 404 observations (including synthetic fertilizer and zero-N control) in 29 sites. Results showed that soil type affected EFs, that is, the mean EF of Andosols was lower than that of non-Andosols, which is similar to the case of EFs for synthetic fertilizer. Mean EFs for poultry manure compost, swine manure compost, cattle manure (compost and slurry), and non-animal manure organic fertilizers were 0.83 % (uncertainty range of 2.5th and 97.5th percentile: 0.09 % to 3.46 %), 0.70 % (0.02 % to 2.45 %), 0.39 % (0.00 % to 1.62 %), and 1.16 % (0.41 % to 3.03 %), respectively, when weighted by area of soil types. The mean EF of all organic amendments was 0.84 % (0.00 % to 2.91 %), when the area of soil type and amount of organic amendment used in Japan were considered. Our study provides country-specific EFs to estimate N₂O emission from organic amendments in Japan.

Genome-Based Taxonomic Rearrangement of the Order Geobacterales Including the Description of Geomonas azotofigens sp. nov. and Geomonas diazotrophica sp. nov

Geobacterales is a recently proposed order comprising members who originally belonged to the well-known family Geobacteraceae, which is a key group in terrestrial ecosystems involved in biogeochemical cycles and has been widely investigated in bioelectrochemistry and bioenergy fields. Previous studies have illustrated the taxonomic structure of most members in this group based on genomic phylogeny; however, several members are still in a pendent or chaotic taxonomic status owing to the lack of genome sequences. To address this issue, we performed this taxonomic reassignment using currently available genome sequences, along with the description of two novel paddy soil-isolated strains, designated Red51^T and Red69^T, which are phylogenetically located within this order. Phylogenomic analysis based on 120 ubiquitous single-copy proteins robustly separated the species Geobacter luticola from other known genera and placed the genus Oryzomonas (fam. Geobacteraceae) into the family ‘Pseudopelobacteraceae’; thus, a novel genus Geomobilimonas is proposed, and the family ‘Pseudopelobacteraceae’ was emended. Moreover, genomic comparisons with similarity indexes, including average amino acid identity (AAI), percentage of conserved protein (POCP), and average nucleotide identity (ANI), showed proper thresholds as genera boundaries in this order with values of 70%, 65%, and 74% for AAI, POCP, and ANI, respectively. Based on this, the three species Geobacter argillaceus, Geobacter pelophilus, and Geobacter chapellei should be three novel genera, for which the names Geomobilibacter, Geoanaerobacter, and Pelotalea are proposed, respectively. In addition, the two novel isolated strains phylogenetically belonged to the genus Geomonas, family Geobacteraceae, and shared genomic similarity values higher than those of genera boundaries, but lower than those of species boundaries with each other and their neighbors. Taken together with phenotypic and chemotaxonomic characteristics similar to other Geomonas species, these two strains, Red51^T and Red69^T, represent two novel species in the genus Geomonas, for which the names Geomonas azotofigens sp. nov. and Geomonas diazotrophica sp. nov. are proposed, respectively.

Revisiting the involvement of ammonia oxidizers and denitrifiers in nitrous oxide emission from cropland soils

Nitrous oxide (N₂O), an ozone-depleting greenhouse gas, is generally produced by soil microbes, particularly NH₃ oxidizers and denitrifiers, and emitted in large quantities after N fertilizer application in croplands. N₂O can be produced via multiple processes, and reduced, with the involvement of more diverse microbes with different physiological constraints than previously thought; therefore, there is a lack of consensus on the production processes and microbes involved under different agricultural practices. In this study, multiple approaches were applied, including N₂O isotopocule analyses, microbial gene transcript measurements, and selective inhibition assays, to revisit the involvement of NH₃ oxidizers and denitrifiers, including the previously-overlooked taxa, in N₂O emission from a cropland, and address the biological and environmental factors controlling the N₂O production processes. Then, we synthesized the results from those approaches and revealed that the overlooked denitrifying bacteria and fungi were more involved in N₂O production than the long-studied ones. We also demonstrated that the N₂O production processes and soil microbes involved were different based on fertilization practices (plowing or surface application) and fertilization types (manure or urea). In particular, we identified the following intensified activities: (1) N₂O production by overlooked denitrifying fungi after manure fertilization onto soil surface; (2) N₂O production by overlooked denitrifying bacteria and N₂O reduction by long-studied N₂O-reducing bacteria after manure fertilization into the plowed layer; and (3) N₂O production by NH₃-oxidizing bacteria and overlooked denitrifying bacteria and fungi when urea fertilization was applied into the plowed layer. We finally propose the conceptual scheme of N flow after fertilization based on distinct physiological constraints among the diverse NH₃ oxidizers and denitrifiers, which will help us understand the environmental context-dependent N₂O emission processes.

Geomesophilobacter sediminis gen. nov., sp. nov., Geomonas propionica sp. nov. and Geomonas anaerohicana sp. nov., three novel members in the family Geobacterecace isolated from river sediment and paddy soil

Bacteria in the family Geobacteraceae have been proven to fill important niches in a diversity of anaerobic environments and global biogeochemical processes. Here, three bacterial strains in this family, designated Red875^T, Red259^T, and Red421^T were isolated from river sediment and paddy soils in Japan. All of them are Gram-staining-negative, strictly anaerobic, motile, flagellum-harboring cells that form red colonies on agar plates and are capable of utilizing Fe(III)-NTA, Fe(III) citrate, ferrihydrite, MnO₂, fumarate, and nitrate as electron acceptors with acetate, propionate, pyruvate, and glucose as electron donors. Phylogenetic analysis based on the 16S rRNA gene and 92 concatenated core proteins sequences revealed that strains Red259^T and Red421^T clustered with the type strains of Geomonas species, whereas strain Red875^T formed an independent lineage within the family Geobacteraceae. Genome comparison based on  average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH) values clearly distinguished these three strains from other Geobacteraceae members, with lower values than the thresholds for species delineation. Moreover, strain Red875^T also shared low average amino acid identity (AAI) and percentage of conserved proteins (POCP) values with the type species of the family Geobacteraceae. Based on these physiological, chemotaxonomic, and phylogenetic distinctions, we propose that strain Red875^T (=NBRC 114290^T = MCCC 1K04407^T) represents a novel genus in the family Geobacteraceae, namely, Geomesophilobacter sediminis gen. nov., sp. nov., and strains Red259^T (=NBRC 114288^T = MCCC 1K05016^T) and Red421^T (=NBRC 114289^T = MCCC 1K06216^T) represent two novel independent species in the genus Geomonas, namely, Geomonas propionica sp. nov. and Geomonas anaerohicana sp. nov., respectively.

Geomonas silvestris sp. nov., Geomonas paludis sp. nov. and Geomonas limicola sp. nov., isolated from terrestrial environments, and emended description of the genus Geomonas

Three bacterial strains, designated Red330^T, Red736^T and Red745^T, were isolated from forest and paddy soils in Japan. Strains Red330^T, Red736^T and Red745^T are flagella-harbouring and strictly anaerobic bacteria forming red colonies. A 16S rRNA gene sequence-based phylogenetic tree showed that all three strains were located in a cluster, including the type strains of Geomonas species, which were recently separated from the genus Geobacter within the family Geobacteraceae. Similarities of the 16S rRNA gene sequences among the three strains and Geomonas oryzae S43^T, the type species of the genus Geomonas, were 96.3-98.5 %. The genome-related indexes, average nucleotide identity, digital DNA-DNA hybridization, and average amino acid identity, among the three strains and G. oryzae S43^T were 74.7-86.8 %, 21.2-33.3 % and 70.4-89.8 %, respectively, which were lower than the species delineation thresholds. Regarding the phylogenetic relationships based on genome sequences, the three strains clustered with the type strains of Geomonas species, which were independent from the type strains of Geobacter species. The distinguishableness of the three isolated strains was supported by physiological and chemotaxonomic properties, with the profile of availability of electron donors and cellular fatty acids composition being particularly different among them. Based on genetic, phylogenetic and phenotypic properties, the three isolates represent three novel independent species in the genus Geomonas, for which the names Geomonas silvestris sp. nov., Geomonas paludis sp. nov. and Geomonas limicola sp. nov. are proposed. The type strains are Red330^T (=NBRC 114028^T=MCCC 1K03949^T), Red736^T (=NBRC 114029^T=MCCC 1K03950^T) and Red745^T (=NBRC 114030^T=MCCC 1K03951^T), respectively.

Dissimilatory Nitrate Reduction to Ammonium and Responsible Microbes in Japanese Rice Paddy Soil

Nitrification–denitrification processes in the nitrogen cycle have been extensively examined in rice paddy soils. Nitrate is generally depleted in the reduced soil layer below the thin oxidized layer at the surface, and this may be attributed to high denitrification activity. In the present study, we investigated dissimilatory nitrate reduction to ammonium (DNRA), which competes with denitrification for nitrate, in order to challenge the conventional view of nitrogen cycling in paddy soils. We performed paddy soil microcosm experiments using ¹⁵N tracer analyses to assess DNRA and denitrification rates and conducted clone library analyses of transcripts of nitrite reductase genes (nrfA, nirS, and nirK) in order to identify the microbial populations carrying out these processes. The results obtained showed that DNRA occurred to a similar extent to denitrification and appeared to be enhanced by a nitrate limitation relative to organic carbon. We also demonstrated that different microbial taxa were responsible for these distinct processes. Based on these results and previous field observations, nitrate produced by nitrification within the surface oxidized layer may be reduced not only to gaseous N₂ via denitrification, but also to NH₄⁺ via DNRA, within the reduced layer. The present results also indicate that DNRA reduces N loss through denitrification and nitrate leaching and provides ammonium to rice roots in rice paddy fields.

Distinct Community Composition of Previously Uncharacterized Denitrifying Bacteria and Fungi across Different Land-Use Types

Recent studies demonstrated that phylogenetically more diverse and abundant bacteria and fungi than previously considered are responsible for denitrification in terrestrial environments. We herein examined the effects of land-use types on the community composition of those denitrifying microbes based on their nitrite reductase gene (nirK and nirS) sequences. These genes can be phylogenetically grouped into several clusters. We used cluster-specific PCR primers to amplify nirK and nirS belonging to each cluster because the most widely used primers only amplify genes belonging to a single cluster. We found that the dominant taxa as well as overall community composition of denitrifying bacteria and fungi, regardless of the cluster they belonged to, differed according to the land-use type. We also identified distinguishing taxa based on individual land-use types, the distribution of which has not previously been characterized, such as denitrifying bacteria or fungi dominant in forest soils, Rhodanobacter having nirK, Penicillium having nirK, and Bradyrhizobium having nirS. These results suggest that land-use management affects the ecological constraints and consequences of denitrification in terrestrial environments through the assembly of distinct communities of denitrifiers.

Geomonas oryzae gen. nov., sp. nov., Geomonas edaphica sp. nov., Geomonas ferrireducens sp. nov., Geomonas terrae sp. nov., Four Ferric-Reducing Bacteria Isolated From Paddy Soil, and Reclassification of Three Species of the Genus Geobacter as Members of the Genus Geomonas gen. nov

In paddy soil, bacteria from the family Geobacteraceae have been shown to strongly contribute to the biogeochemical cycle. However, no Geobacteraceae species with validly published names have been isolated from paddy soil. In this study, we isolated and characterized four novel ferric reducing bacteria in the family Geobacteraceae from the paddy soils of three different fields in Japan. The four strains, S43T, Red53T, S62T, and Red111T, were Gram-stain negative, strictly anaerobic, chemoheterotrophic, and motile with peritrichous flagella. Phylogenetic studies based on 16S rRNA gene sequences, five concatenated housekeeping genes (fusA, rpoB, recA, nifD, and gyrB) and 92 concatenated core genes revealed that the four strains belong to the family Geobacteraceae and are most closely related to Geobacter bemidjiensis BemT (97.4-98.2%, 16S rRNA gene sequence similarities) and Geobacter bremensis Dfr1T (97.1-98.0%). Genomic analysis with average nucleotide identity (ANI) and digital DNA-DNA hybridization (GGDC) calculations clearly distinguished the four isolated strains from other species of the family Geobacteraceae and indicated that strains S43T, Red53T, S62T, and Red111T represent independent species, with values below the thresholds for species delineation. Chemotaxonomic characteristics, including major fatty acid and whole cell protein profiles, showed differences among the isolates and their closest relatives, which were consistent with the results of DNA fingerprints and physiological characterization. Additionally, each of the four isolates shared a low 16S rRNA gene sequence similarity (92.4%) and average amino acid identity (AAI) with the type strain of the type species Geobacter metallireducens. Overall, strains S43T, Red53T, S62T, and Red111T represent four novel species, which we propose to classify in a novel genus of the family Geobacteraceae, and the names Geomonas oryzae gen. nov., sp. nov. (type strain S43T), Geomonas edaphica sp. nov. (type strain Red53T), Geomonas ferrireducens sp. nov. (type strain S62T), and Geomonas terrae sp. nov. (type strain Red111T) are proposed. Based on phylogenetic and genomic analyses, we also propose the reclassification of Geobacter bremensis as Geomonas bremensis comb. nov., Geobacter pelophilus as Geomonas pelophila comb. nov., and Geobacter bemidjiensis as Geomonas bemidjiensis comb. nov.

Predominant but Previously-overlooked Prokaryotic Drivers of Reductive Nitrogen Transformation in Paddy Soils, Revealed by Metatranscriptomics

Waterlogged paddy soils possess anoxic zones in which microbes actively induce reductive nitrogen transformation (RNT). In the present study, a shotgun RNA sequencing analysis (metatranscriptomics) of paddy soil samples revealed that most RNT gene transcripts in paddy soils were derived from Deltaproteobacteria, particularly the genera Anaeromyxobacter and Geobacter. Despite the frequent detection of the rRNA of these microbes in paddy soils, their RNT-associated genes have rarely been identified in previous PCR-based studies. This metatranscriptomic analysis provides novel insights into the diversity of RNT microbes present in paddy soils and the ecological function of Deltaproteobacteria predominating in these soils.

Higher diversity and abundance of denitrifying microorganisms in environments than considered previously

Denitrification is an important process in the global nitrogen cycle. The genes encoding NirK and NirS (nirK and nirS), which catalyze the reduction of nitrite to nitric oxide, have been used as marker genes to study the ecological behavior of denitrifiers in environments. However, conventional polymerase chain reaction (PCR) primers can only detect a limited range of the phylogenetically diverse nirK and nirS. Thus, we developed new PCR primers covering the diverse nirK and nirS. Clone library and qPCR analysis using the primers showed that nirK and nirS in terrestrial environments are more phylogenetically diverse and 2-6 times more abundant than those revealed with the conventional primers. RNA- and culture-based analyses using a cropland soil also suggested that microorganisms with previously unconsidered nirK or nirS are responsible for denitrification in the soil. PCR techniques still have a greater capacity for the deep analysis of target genes than PCR-independent methods including metagenome analysis, although efforts are needed to minimize the PCR biases. The methodology and the insights obtained here should allow us to achieve a more precise understanding of the ecological behavior of denitrifiers and facilitate more precise estimate of denitrification in environments.

Seasonal transition of active bacterial and archaeal communities in relation to water management in paddy soils

Paddy soils have an environment in which waterlogging and drainage occur during the rice growing season. Fingerprinting analysis based on soil RNA indicated that active microbial populations changed in response to water management conditions, although the fundamental microbial community was stable as assessed by DNA-based fingerprinting analysis. Comparative clone library analysis based on bacterial and archaeal 16S rRNAs (5,277 and 5,436 clones, respectively) revealed stable and variable members under waterlogged or drained conditions. Clones related to the class Deltaproteobacteria and phylum Euryarchaeota were most frequently obtained from the samples collected under both waterlogged and drained conditions. Clones related to syntrophic hydrogen-producing bacteria, hydrogenotrophic methanogenic archaea, rice cluster III, V, and IV, and uncultured crenarchaeotal group 1.2 appeared in greater proportion in the samples collected under waterlogged conditions than in those collected under drained conditions, while clones belonging to rice cluster VI related to ammonia-oxidizing archaea (AOA) appeared at higher frequency in the samples collected under drained conditions than in those collected under waterlogged conditions. These results suggested that hydrogenotrophic methanogenesis may become active under waterlogged conditions, whereas ammonia oxidation may progress by rice cluster VI becoming active under drained conditions in the paddy field.

Percutaneous ethanol injection therapy for hepatocellular-carcinoma (review)

Recently, ultrasound-guided percutaneous ethanol injection therapy (PEIT) has been widely performed in the treatment of hepatocellular carcinoma. Histopathologic examinations after the therapy have revealed that PEIT can destroy the tumor completely in most cases. Findings in imaging modalities and serum tumor marker levels have also shown a remarkable anticancer effect of this procedure. In addition, PEIT has achieved considerably high long-term survival rates. PEIT is a generally safe procedure and serious complications are rare. PEIT seems to be a valuable therapy and could even be an alternative to surgery in the treatment of hepatocellular carcinoma. This paper reviews the pertinent literature on this new therapy.

Alcohol consumption appears to protect against non-alcoholic fatty liver disease

BACKGROUND

Moderate alcohol consumption may have certain beneficial effects against non-alcoholic fatty liver disease, which is associated with metabolic syndrome.

AIM

To determine the association between drinking pattern and fatty liver in Japanese men and women.

METHODS

A cross-sectional study was performed with health checkup data including information concerning alcohol consumption and ultrasonographic assessment of fatty liver.

RESULTS

We analysed 4957 men and 2155 women without reported liver diseases (median age, 49 years). In men, 40% of nondrinkers and 28% of drinkers had fatty liver. Alcohol consumption was inversely associated with fatty liver (adjusted odds ratio, 0.54; 95% confidence interval, 0.46-0.63). The prevalence of fatty liver in each category of drinking frequency was 38% (1-3 days/week), 29% (4-6 days/week), and 24% (daily drinking); there was a significant inverse correlation between drinking frequency and the prevalence of fatty liver (P < 0.001). In women, 16% of nondrinkers and 10% of drinkers had fatty liver. Drinking less than 20 g on 1-3 days/week was associated with low prevalence of fatty liver (adjusted odds ratio, 0.47; 95% confidence interval, 0.23-0.96).

CONCLUSIONS

Alcohol consumption appears to protect against non-alcoholic fatty liver disease.

Predictive factors of efficacy of leukocytapheresis for steroid-resistant ulcerative colitis patients

BACKGROUND

The effectiveness of leukocytapheresis against ulcerative colitis has been reported. However, the efficacy of this therapy for steroid-resistant ulcerative colitis patients has hardly been examined.

AIMS

The aims of this study are to evaluate the efficacy of leukocytapheresis for steroid-resistant ulcerative colitis patients and to identify clinical factors that predict the efficacy of this therapy for these patients.

METHODS

Clinical factors of 71 steroid-resistant ulcerative colitis patients who underwent leukocytapheresis analysed.

RESULTS

Of those analysed, 53 (75%) patients showed an initial response to leukocytapheresis. Among cases with initial response, however, only 19 (27%) patients maintained remission for more than 6 months. Steroid-dependent course (Odds ratio =5.53, 95% confidence interval; 1.24-24.73) and a high C-reactive protein degree (Odds ratio=1.6, confidence interval; 1.09-2.35) were predictors of initial response to leukocytapheresis. Rapid response, which means remission induction within three leukocytapheresis sessions, was the only predictor of maintenance of remission for more than 6 months after successful leukocytapheresis therapy (odds ratio=8.01, confidence interval; 1.08-59.37).

CONCLUSIONS

Leukocytapheresis was effective for steroid-resistant ulcerative colitis patients. However, relapse was frequently observed within short periods after the initial response to this therapy. Patients without a rapid response should be treated with alternative or additional therapies.

Helicobacter pylori eradication reduced the incidence of gastric cancer, especially of the intestinal type

BACKGROUND

Although Helicobacter pylori infection is closely associated with gastric cancer development, follow-up studies after H. pylori eradication are still scarce.

AIM

To clarify the cancer preventive effect of H. pylori eradication, with special attention to differences in effect according to histology.

METHODS

Patients who underwent H. pylori eradication therapy and were followed-up endoscopically for at least 1 year were analysed. The incidence of gastric cancer and factors associated with cancer development were investigated.

RESULTS

A total of 1807 patients were enrolled. Six of 1519 H. pylori eradicated and five of 288 persistent subjects developed gastric cancer. Four of the eradicated subjects developed the intestinal type and two the diffuse type, while four of the persistent subjects developed the intestinal type and one the diffuse type. Kaplan-Meier analysis indicated a significantly lower incidence in eradicated patients than in persistent patients. The incidence of intestinal type was significantly lower than in eradicated patients, while the diffuse type could not be evaluated because of the low incidence.

CONCLUSIONS

Helicobacter pylori-eradicated patients had a reduced incidence of gastric cancer compared with H. pylori-persistent patients, particularly the intestinal type, suggesting that H. pylori is strongly associated with intestinal-type gastric cancer.

Therapeutic efficacy of leukocytapheresis in a pregnant woman with severe active ulcerative colitis

Leukocytapheresis has recently been used to induce remission in patients with ulcerative colitis (UC) who fail to respond to corticosteroids. We could not find a report in the literature on leukocytapheresis for UC with gestational exacerbation. We have recently encountered this unique condition and report the details here. A 30-year-old Japanese woman with left-sided severe UC was corticosteroid-dependent and had recurrence of the active disease during tapering of corticosteroid. She declined any dose increase and the use of any immunosuppressive agent because she was in the 13th week of pregnancy. Then, concomitant leukocytapheresis was performed without increasing the corticosteroid dose. Recovery was rapid and dramatic. Mucous and bloody stool decreased after the first session, and she had remission 2 weeks later. She underwent a total of four sessions without complications. After 6 weeks, she was discharged from our hospital and underwent maintenance treatment as an outpatient with mesalazine and corticosteroid tapering. Subsequently, she gave birth to a healthy baby girl by an uncomplicated vaginal delivery while keeping the remitted stage of UC.

Clinical characteristics of synchronous colorectal cancer are different according to tumour location

AIMS

The purpose of this study was to investigate the clinical characteristics of synchronous cancer patients, with particular attention given to variations in tumour location.

METHODS

A retrospective evaluation of 249 synchronous cancer cases out of 3061 consecutive colorectal cancer patients.

RESULTS

Multivariate analysis of risk factors for synchronous cancer according to tumour location revealed that male gender was a significant risk for synchronous lesions in the left colon only (odds ratio=2.05, 95% confidence interval 1.34-3.13). Meanwhile, aging was a risk factor for synchronous cancer in the right colon only (odds ratio=1.05, 95% confidence interval 1.02-1.08), and in both sides of the colon (odds ratio=1.03, 95% confidence interval 1.01-1.05), but not in the left colon only (odds ratio=0.98, 95% confidence interval 0.97-1.00). In addition, patients with synchronous lesions in the right colon only tended to have adenomas in the right colon, while those with synchronous lesions in the left colon only tended to have adenomas in the left colon (each P value <0.05).

CONCLUSION

The risk factors and status of concurrent adenomas of synchronous cancer cases varied according to tumour location, suggesting that the colonic site susceptible to neoplasia varies according to patient characteristics.

Persistent elevation of serum alanine aminotransferase levels leads to poor survival and hepatocellular carcinoma development in type 1 autoimmune hepatitis

BACKGROUND

Although the prognosis of type 1 autoimmune hepatitis is generally good with immunosuppressive treatment, the disease progresses in some patients despite the treatment. The prognosis may be determined by the clinical course.

AIM

To evaluate the long-term prognosis and assess the predictive factors for a serious event, including the development of hepatocellular carcinoma or death.

METHODS

Sixty-nine patients with type 1 autoimmune hepatitis were prospectively followed up regularly, with a median follow-up period of 96 months (49-201 months).

RESULTS

During the follow-up period, three patients (4%) developed hepatocellular carcinoma, and two of these three patients died. Another patient died of liver failure. The 10-year survival rate was 98%, and the 10-year hepatocellular carcinoma-free rate was 93%. The four patients experiencing a serious event received higher maintenance doses of corticosteroid during their follow-up periods than those did not. However, serum alanine aminotransferase levels during the follow-up period were higher in these four patients than in the others.

CONCLUSIONS

Persistent elevation of serum alanine amniotransferase levels during the follow-up period, rather than factors existing prior to medical treatment is considered to be an important prognostic factor, and it is indicated that poor outcomes may result from the resistance to immunosuppressive treatment.

Endoscopic submucosal dissection for early gastric cancer: results and degrees of technical difficulty as well as success

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) is a new method for the curative treatment of early gastrointestinal neoplasms, which was developed in order to increase the en bloc and R0 resection rate, especially for lesions larger than 20 mm in diameter. Drawbacks of ESD include the fact that it is technically a substantially more difficult procedure and that it is associated with a higher perforation rate. A retrospective study was therefore carried out to analyze cases in relation to the procedure time and resection success, and these factors were correlated with the characteristics of the lesions.

PATIENTS AND METHODS

From January 2002 to November 2005, 196 lesions in 185 patients with early gastric cancer were treated using ESD in our hospital. The rates of curative en bloc resection, the incidence of perforation, and the procedure times were analyzed in relation to lesion size (small, 20 mm or less in diameter; large, over 20 mm), location (upper, middle, or lower third of the stomach) and the presence or absence of ulceration.

RESULTS

The rate of curative en bloc resection was 84 % (93 % of the lesions overall were resected in one piece), with a perforation rate of 6.1 % (all perforations were managed endoscopically) and a mean procedure time of 68 min. The rate of curative en bloc resection differed significantly depending on the location of the lesion (upper vs. middle vs. lower, 74 % vs. 77 % vs. 91 %; P < 0.05), as well as on the size of the lesion (> 20 mm vs. 20 mm or less, 59 % vs. 89 %; P < 0.0001). There were also significant differences in the mean procedure times in relation to the location of the lesion (upper vs. middle vs. lower, 105 min vs. 81 min vs. 45 min; P < 0.0001) and the size of the lesion (> 20 mm vs. 20 mm or less, 124 min vs. 55 min; P < 0.0001), as well as the presence of ulceration (positive vs. negative, 97 min vs. 65 min; P < 0.05). With regard to perforation rates, significant differences were also observed in relation to the location of the lesion (upper vs. middle vs. lower, 22.6 % vs. 2.8 % vs. 3.2 %; P < 0.0005) and size of the lesion (> 20 mm vs. 20 mm or less, 16.2 % vs. 3.8 %; P < 0.005). No local recurrences of curatively resected lesions (n = 119) were observed after a follow-up period of 1 year.

CONCLUSIONS

The difficulty of ESD depends on the location and size of the lesion, as well as on the presence of ulceration. We would recommend that trainees should begin by carrying out ESD on lesions with a diameter of less than 20 mm without ulceration that are located in the lower third of the stomach.

Endoscopic submucosal dissection for early gastric cancer: results and degrees of technical difficulty as well as success

BACKGROUND AND STUDY AIMS

Endoscopic submucosal dissection (ESD) is a new method for the curative treatment of early gastrointestinal neoplasms, which was developed in order to increase the en bloc and R0 resection rate, especially for lesions larger than 20 mm in diameter. Drawbacks of ESD include the fact that it is technically a substantially more difficult procedure and that it is associated with a higher perforation rate. A retrospective study was therefore carried out to analyze cases in relation to the procedure time and resection success, and these factors were correlated with the characteristics of the lesions.

PATIENTS AND METHODS

From January 2002 to November 2005, 196 lesions in 185 patients with early gastric cancer were treated using ESD in our hospital. The rates of curative en bloc resection, the incidence of perforation, and the procedure times were analyzed in relation to lesion size (small, 20 mm or less in diameter; large, over 20 mm), location (upper, middle, or lower third of the stomach) and the presence or absence of ulceration.

RESULTS

The rate of curative en bloc resection was 84 % (93 % of the lesions overall were resected in one piece), with a perforation rate of 6.1 % (all perforations were managed endoscopically) and a mean procedure time of 68 min. The rate of curative en bloc resection differed significantly depending on the location of the lesion (upper vs. middle vs. lower, 74 % vs. 77 % vs. 91 %; P < 0.05), as well as on the size of the lesion (> 20 mm vs. 20 mm or less, 59 % vs. 89 %; P < 0.0001). There were also significant differences in the mean procedure times in relation to the location of the lesion (upper vs. middle vs. lower, 105 min vs. 81 min vs. 45 min; P < 0.0001) and the size of the lesion (> 20 mm vs. 20 mm or less, 124 min vs. 55 min; P < 0.0001), as well as the presence of ulceration (positive vs. negative, 97 min vs. 65 min; P < 0.05). With regard to perforation rates, significant differences were also observed in relation to the location of the lesion (upper vs. middle vs. lower, 22.6 % vs. 2.8 % vs. 3.2 %; P < 0.0005) and size of the lesion (> 20 mm vs. 20 mm or less, 16.2 % vs. 3.8 %; P < 0.005). No local recurrences of curatively resected lesions (n = 119) were observed after a follow-up period of 1 year.

CONCLUSIONS

The difficulty of ESD depends on the location and size of the lesion, as well as on the presence of ulceration. We would recommend that trainees should begin by carrying out ESD on lesions with a diameter of less than 20 mm without ulceration that are located in the lower third of the stomach.

Clinical features of Japanese male patients with type 1 autoimmune hepatitis

BACKGROUND

Recently, unusual patients with autoimmune hepatitis, such as male patients, have increased.

AIM

To assess clinical feature of Japanese males with type 1 autoimmune hepatitis compared with females.

METHODS

We investigated consecutive 160 patients with type 1 autoimmune hepatitis, who consisted of 20 males and 140 females, with a median age of 55 (16-79) years.

RESULTS

Compared with females, males had a lower frequency of definite diagnosis according to the revised scoring system proposed by the International Autoimmune Hepatitis Group (40% vs. 85%) and lower serum levels of immunoglobulin G [1932 (1085-3850) mg/dL vs. 2624 (1354-6562) mg/dL]. However, they were similar in age, form of clinical onset, symptomatic concurrent autoimmune disease, human leucocyte antigen DR status and frequency of cirrhosis at the time of diagnosis. The normalization of serum alanine aminotransferase levels within 6 months after the introduction of corticosteroid treatment was lower in males compared with females (73% vs. 93%).

CONCLUSIONS

In male patients, a diagnosis of autoimmune hepatitis should be made carefully. In Japanese patients with a dominant frequency of human leucocyte antigen DR4, gender may affect the response to corticosteroid treatment.

Clinical characteristics of fulminant-type autoimmune hepatitis: an analysis of eleven cases

BACKGROUND

Although a few adult cases of fulminant-type autoimmune hepatitis have been reported, their clinical features and prognosis have remained uncertain.

AIM

To assess the clinical features and prognosis of patients with fulminant-type autoimmune hepatitis.

METHODS

Eleven patients (10%) diagnosed with fulminant-type autoimmune hepatitis in accordance with the 1999 criteria of the International Autoimmune Hepatitis Group were analysed.

RESULTS

All 11 patients were female, with a median age of 53 years. Five patients survived without liver transplantation, one received a liver transplantation, and five died without liver transplantation. Nine patients (82%) survived for 2 weeks or more following diagnosis, without liver transplantation. Except for the patient receiving a liver transplantation, serum total bilirubin levels measured during the clinical course were significantly higher in non-survivors than in survivors, although the accompanying serum alanine aminotransferase levels measured for the two groups were similar. Most significantly, serum total bilirubin levels in non-survivors worsened during days 8-15, while levels in survivors improved during the same period.

CONCLUSIONS

The short-term prognosis for patients with fulminant-type autoimmune hepatitis may be good. However, patients whose serum total bilirubin levels worsen during days 8-15 should be considered for liver transplantation.

Evaluation of covered metallic stents in malignant biliary stenosis--prominent effectiveness in gallbladder carcinoma

BACKGROUND/AIMS

The survival time of patients with unresectable malignant biliary stenosis and the patent period of metallic biliary stents are different in each disease. The efficacy of the covered metallic stent was analyzed according to the primary disease.

METHODOLOGY

Seventy-three patients with bile duct carcinoma (12 cases), gallbladder carcinoma (22 cases), and pancreas carcinoma (39 cases) were retrospectively enrolled. Covered metallic stents were used in 42 patients and uncovered metallic stents in 31 patients. The patency of covered stents was compared with that of uncovered stents for each disease.

RESULTS

The patent rate at 6 months after insertion was 80.6% (95% CI [72.6%, 88.6%]) for the covered stent, and 49.5% (95% CI [37.6%, 61.4%]) for the uncovered stent. The mean patent periods of the covered stent and the uncovered stent were 14.6 and 27.6 months for bile duct carcinoma (p=0.424), 12.7 and 3.0 months for gallbladder carcinoma (p=0.003), and 11.9 and 9.6 months for pancreas carcinoma (p=0.919), respectively.

CONCLUSIONS

The covered metallic stent was the most effective in patients with gallbladder carcinoma.

Eradication of Helicobacter pylori increases platelet count in patients with idiopathic thrombocytopenic purpura in Japan

BACKGROUND

The effect of Helicobacter pylori eradication on the platelet count in patients with thrombocytopenic purpura is controversial. In this multicentre study, we prospectively assessed the effect of H. pylori eradication therapy in idiopathic thrombocytopenic purpura patients.

MATERIALS AND METHODS

Thirty-five consecutive patients with chronic idiopathic thrombocytopenic purpura (11 males and 24 females, a median age of 57) were assessed for H. pylori infection by use of a urea breath test. All patients received 1-week triple therapy (amoxicillin, clarithromycin, and lansoprazole) to eradicate H. pylori. At 6 months, idiopathic thrombocytopenic purpura patients with a platelet count recovery of greater than 100 x 10(9) L(-1) were defined as idiopathic thrombocytopenic purpura responders.

RESULTS

Helicobacter pylori infection was observed in 25 (71%) of the 35 patients. All infected patients were cured. Eleven patients were identified as idiopathic thrombocytopenic purpura responders; 24 were considered nonresponders. Platelet counts improved by more than 100 x 10(9) L(-1) in 11 (44%) of the 25 patients cured of H. pylori infection, while none of the 10 patients H. pylori-negative patients experienced the same improvement (P = 0.015). Univariate analysis showed that H. pylori infection and its eradication were significant factors associated with platelet recovery (P = 0.015).

CONCLUSIONS

Helicobacter pylori infection played a role in the pathogenesis of idiopathic thrombocytopenic purpura in approximately 30% of all patients assessed and 45% of the patients with H. pylori infection. Eradication of H. pylori in idiopathic thrombocytopenic purpura patients led to improved disease activity.

A prospective randomised study of "covered" versus "uncovered" diamond stents for the management of distal malignant biliary obstruction

BACKGROUND AND AIM

Covered self-expandable metal stents (EMS) were recently developed to overcome tumour ingrowth in conventional EMS. However, supporting evidence for the efficacy of covered EMS is lacking.

PATIENTS AND METHODS

We enrolled 112 patients with unresectable distal biliary malignancies. They were randomly assigned to polyurethane covered (n = 57) or original diamond stent (n = 55).

RESULTS

Stent occlusion occurred in eight patients (14%) after a mean of 304 days in the covered group, and in 21 patients (38%) after a mean of 166 days in the uncovered group. The incidence of covered EMS occlusion was significantly lower than that of uncovered EMS (p = 0.0032). The cumulative stent patency of covered stents was significantly higher than that of uncovered stents (p = 0.0066). No tumour ingrowth occurred in the covered group while it was observed in 15 patients in the uncovered group. In subgroup analysis, the cumulative patency of the covered EMS was significantly higher in pancreatic cancer (p = 0.0363) and metastatic lymph nodes (p = 0.0354). There was no significant difference in survival between the two groups. Acute cholecystitis was observed in two of the covered group and in none of the uncovered group. Mild pancreatitis occurred in five of the covered group and in one of the uncovered group.

CONCLUSIONS

Covered diamond stents successfully prevented tumour ingrowth and were significantly superior to uncovered stents for the treatment of patients with distal malignant biliary obstruction. However, careful attention must be paid to complications specific to covered self-expandable metal stents, such as acute cholecystitis and pancreatitis.

Coronary Flow Reserve after Coronary Intervention is Similar in Patients with Preserved Viability in Previous Myocardial Infarction and in Those with Angina Pectoris

The relationship between coronary flow reserve (CFR) and viability in the infarcted myocardium has not been fully clarified. We measured coronary blood flow velocity immediately after coronary intervention (with percutaneous transluminal coronary angioplasty [PTCA] or stenting) in 38 patients with previous myocardial infarction and preserved viability and 48 with angina pectoris. CFR was calculated and was similar between the two patient groups. No differences in the incidence of post-intervention CFR > 2.0 were detected; there were no differences in postintervention CFR between patients with preserved myocardial viability and those with angina pectoris who underwent PTCA. Coronary stenting reduced the percentage diameter stenosis in both groups compared with PTCA and slightly increased the post-intervention CFR. No differences were, however, detected in postintervention CFR between patients with preserved myocardial viability and those with angina pectoris who underwent additional stenting. These results reveal that in patients with preserved myocardial viability, post-intervention CFR was restored to values similar to those in patients with angina pectoris.

Benefit of interferon therapy in hepatocellular carcinoma prevention for individual patients with chronic hepatitis C

BACKGROUND

An increase in the incidence of hepatocellular carcinoma (HCC) in Japan since the 1980s suggests an imminent outbreak in other countries where viral spread occurred more recently. Interferon therapy for chronic hepatitis C, in general, has been shown to prevent HCC.

AIMS

To determine the scale of benefit in individual patients.

SUBJECTS

Histologically proven chronic hepatitis C patients in the Inhibition of Hepatocarcinogenesis by Interferon Therapy (IHIT) cohort (Ann Intern Med 1999;131:174), as updated in March 2003.

METHODS

The lifetime risk for HCC was calculated based on HCC incidence rates, stratified by sex, age, fibrosis stage, and outcome of interferon therapy. The gain in HCC free survival was defined as the difference between expected HCC free survival with sustained virological response and that without.

RESULTS

The gain in HCC free survival was greater when a patient was younger and fibrosis was more advanced. For example, a 30 year old male with F3 fibrosis gained 12.4 years by attaining sustained response while a patient with F1 fibrosis older than 60 years gained less than one year. For a treatment protocol with a given sustained response rate, prior estimation of the gain can be obtained by multiplying the calculated HCC free survival for responders by the response rate.

CONCLUSIONS

The gain in HCC free survival may serve as an indicator of the benefit of interferon therapy in terms of HCC prevention and be useful in the consideration of indication and selection of treatment protocol for individual patients.

Histological analysis of the papilla after endoscopic papillary balloon dilation

BACKGROUND/AIMS

Endoscopic papillary balloon dilation is an effective procedure in the management of bile duct stones and is believed to preserve the papillary function. The papillary architecture is also considered to be preserved. However, little is known about the effects of balloon dilation on papillary structure. The present study was conducted to elucidate these effects.

METHODOLOGY

Since May 1994, endoscopic papillary balloon dilation was performed in 467 patients (407 patients for removal of bile duct stone, 57 for insertion of stent and 3 for baby cholangioscope). Of those, histological examinations were undertaken in 10 patients. The indications of endoscopic papillary balloon dilation were bile duct stone removal in 2 patients, stent insertion in 8. The specimens were obtained 2 to 63 weeks after endoscopic papillary balloon dilation during surgical operation in 6 patients and autopsy in 4 patients. Serial sections through the papilla were stained by hematoxylin and eosin and Masson's trichrome. The specimens were also obtained from 4 patients without biliary disease as control.

RESULTS

No smooth muscle disruption nor architectural distortion was observed except for one patient who had mild disruption of smooth muscle caused by a biliary drainage tube. However, mild to moderate inflammation and fibrosis were seen in 9 patients and in 8, respectively.

CONCLUSIONS

The papillary architecture is not affected by endoscopic papillary balloon dilation. This may imply that endoscopic papillary balloon dilation preserves papillary function.

A proton-pump inhibitor, rabeprazole, improves ventilatory function in patients with asthma associated with gastroesophageal reflux

BACKGROUND

Treatment of gastroesophageal reflux (GER) with proton-pump inhibitors (PPI) improves symptoms of asthma in some patients. However, the effects of a PPI on ventilatory function are still controversial. In this study, we measured ventilatory function in asthma patients treated with a PPI in order to identify those in whom a therapeutic effect on asthma can be expected from the acid suppression.

METHODS

From a cohort of 114 consecutive patients with bronchial asthma, 53 patients agreed to participate in the study and were treated with rabeprazole 20mg daily for 8 weeks during an asymptomatic, stable period with no exacerbations of their asthma. Of the 53 patients, 22 were diagnosed as GER on the basis of the QUEST questionnaire and endoscopic examination. The patients were monitored for improvement in ventilatory function.

RESULTS

Four patients dropped out because of adverse drug reactions. All the patients with GER noted an improvement in reflux symptoms with PPI treatment. An improvement of more than 20% in peak expiratory flow (PEF) was observed in 8 of 21 GER patients but in none of the non-GER patients. Factors predictive of improvement in PEF with rabeprazole therapy were the QUEST score (odds ratio: 1.47, 95% CI: 1.06-2.04, P = 0.022) and steroid-dependency of asthma (odds ratio: 0.01, 95% CI: 0.001-0.31, P = 0.008).

CONCLUSIONS

Treatment with rabeprazole is expected to ameliorate asthma in non-steroid-dependent patients who have symptomatic GER defined by the QUEST score.

Presence on human chromosome 10 of omeprazole-sensitivity gene whose product mediates CYP1A1 induction

Previously, we showed that CYP1A1 expression can be induced by omeprazole (OP) in the human cell line HepG2, but not in the mouse cell line Hepa-1. Now we show induction of CYP1A1 by alpha-naphthoflavone (alphaNF) in Hepa-1 cells. This induction was inhibited by the tyrosine kinase inhibitor herbimycin A, but not by the aromatic hydrocarbon (Ah)-receptor antagonist PD98059, suggesting the presence of a ligand-independent signal-transduction pathway in the mouse cell line too. We utilized the lack of CYP1A1 induction by OP in Hepa-1 cells to map a putative human gene for OP-respon- siveness in cell hybrids produced by fusion of Hepa-1 and HepG2 cells. OP-induced CYP1A1 expression was detected in four out of the 32 Hepa-1 x HepG2 cell hybrids analyzed. To help identify the gene locus, a radiation-hybrid cell (E11) was constructed. Use of reverse-fluorescence in situ hybridization revealed that these five cell lines commonly retained human chromosome 10p. These results suggest that the human gene for OP-responsiveness is present on chromosome 10p.

Reverse seroconversion of hepatitis B virus after hematopoietic stem cell transplantation

Hepatitis B virus (HBV) reactivation in patients previously positive for hepatitis B surface antibody (HBsAb), so-called reverse seroconversion, has been considered to be a rare complication after hematopoietic stem cell transplantation (HSCT). We experienced two patients who developed reverse seroconversion among nine who were HBsAb positive and Hepatitis B core antibody (HBcAb) positive before HSCT; one after autologous bone marrow transplantation (BMT) and another after allogeneic peripheral blood stem cell transplantation (PBSCT). We reviewed the literature and considered that reverse seroconversion of HBV after HSCT is not uncommon among HBsAb positive recipients. The use of corticosteroids, the lack of HBsAb in donor, and a decrease in serum HBsAb and HBcAb levels may predict reverse seroconversion after HSCT.

Analysis of apoptotic and antiapoptotic signalling pathways induced by Helicobacter pylori

BACKGROUND AND AIMS

Although it is reported that Helicobacter pylori induces apoptosis on gastric epithelial cells, the mechanism remains unknown. Antiapoptotic effects generated by H pylori have not yet been evaluated.

METHODS

(1) H pylori strains (type 1 wild, TN2-deltacagE, TN2-deltavacA) were cocultured with MKN45, TMK1, and HeLa cells, and cell viability and apoptosis were assessed by trypan blue exclusion and DNA laddering, respectively. (2) Activation of caspases-3, 7, and 8, cytochrome c release from the mitochondria, and Fas, Fas associated death domain protein (FADD), Bax, Bak, and Bcl-X expression were evaluated by immunoblot analysis. (3) To investigate whether nuclear factor kappa B (NFkappaB) activation induced by cag pathogenicity island (PAI) positive H pylori affects antiapoptosis, MKN45 cells stably expressing super-repressor IkappaBalpha were cocultured with H pylori, and cell viability and caspase activation were evaluated. NFkappaB regulated gene expression was also evaluated by ribonuclease protection assay.

RESULTS

(1) Wild-type and deltavacA mutant H pylori induced apoptosis more potently than the deltacagE mutant. Inhibition of cell contact between H pylori and cancer cells and heat killing H pylori diminished cell death. (2) Caspases-3, 7, and 8 were activated time dependently by H pylori as well as by the agonist anti-Fas. Cytochrome c release from mitochondria was observed and was not inhibited by caspase-8 inhibitor. Although protein expression of Fas, FADD, Bax, Bak, and Bcl-X in the whole cell lysates was not changed by H pylori, Bax was decreased from mitochondria free cytosol suggesting that Bax was translocated into mitochondria. (3) Cell death and the activities of caspases-3 and 8 were promoted in MKN45 cells stably expressing super-repressor IkappaBalpha that inhibits NFkappaB activation. Antiapoptotic proteins c-IAP1 and c-IAP2 were upregulated by the wild-type strains.

CONCLUSION

cag PAI positive H pylori is capable of inducing apoptotic effects mainly through the mitochondrial pathway. Antiapoptotic effects mediated by NFkappaB activation were also observed.

Vertebral fracture and cortical bone changes in corticosteroid-induced osteoporosis

Despite an intriguing understanding of trabecular bone dynamics, little is known about corticosteroid-induced cortical bone loss and fractures. Recently, we verified a steroid-induced decrease in cortical bone volume and density using peripheral quantitative computed tomography (pQCT) in adult asthmatic patients given oral corticosteroids. Subsequently, the pQCT parameters and presence of vertebral fractures were investigated to further clarify the role of cortical bone quality in fractures in 86 postmenopausal (>5 years after menopause) asthmatic patients on high-dose oral steroid (>10 g cumulative oral prednisolone) (steroid group) and 194 age-matched controls (control group). Cortical and trabecular bone was subjected to measurement of various parameters using pQCT (Stratec XCT960). Relative Cortical Volume (RCV) was calculated by dividing the cortical area by the total bone area. Strength Strain Index (SSI) was determined in the radius based on the density distribution around the axis. Spinal fracture was assessed on lateral radiographs. Patients treated with high doses of oral steroid (>10 g cumulative oral prednisolone) were found to have an increased risk of fracture compared with control women receiving no steroid medication (odds ratio, 8.85; 95% CI, 4.21-18.60) after adjustment was made for years since menopause, body mass index and RCV. In both groups, the diagnostic and predictive ability of the pQCT parameters for vertebral fracture was assessed by the areas under their receiver operating characteristic (ROC) curves. All parameters were found to be significant predictors ( p<0.0001) in the control group. In the steroid group, however, the cortical bone mineral density (BMD) ( p = 0.001), RCV ( p<0.0001) and SSI ( p = 0.001) were found to be significant predictors, but not trabecular BMD ( p = 0.176). For comparison between the two groups, thresholds of all parameters for vertebral fracture were also calculated by the point of coincidence of sensitivity with specificity in ROC testing and the 90th percentile value. Although a rise in fracture threshold in the steroid group was suggested, considerable difference in the values obtained by the two methods of calculation precluded any conclusion. High-dose oral steroid administration was associated with an increased risk of fracture. Cortical bone parameters obtained by pQCT could play a role as good predictors of future corticosteroid-induced vertebral fractures.

The enzymatic basis for the conversion of nonfucosylated to fucosylated alpha-fetoprotein by acyclic retinoid treatment in human hepatoma cells: activation of alpha1-6 fucosyltransferase

The purpose of the present study was to investigate the mechanism by which nonfucosylated alpha-fetoprotein (AFP) is converted to fucosylated AFP in human hepatoma cell lines exposed to acyclic retinoid (AR), an effective drug for the secondary prevention of hepatocellular carcinoma. AR treatment (100 microM) of HepG2 and Hep3B cells significantly increased the activity and mRNA levels of alpha1-6 fucosyltransferase (alpha1-6 FucT), the enzyme responsible for the fucosylation of AFP, leading to an increase in fucosylated glycoproteins as evidenced by lectin binding measurements. Lectin immunoelectrophoresis of AFP obtained from culture media indicated that the relative percentage of nonfucosylated AFP (L1 fraction) was decreased and alpha1-6 fucosylated AFP (L3 fraction) was increased in these hepatoma cell lines after treatment with AR. The total AFP levels were, however, markedly suppressed by AR treatment, and therefore the absolute L3 fraction on the basis of the total AFP present was extremely low. These results demonstrate that AR enhances the conversion of the L1 to the L3 fraction due to the activation of alpha1-6 FucT in human hepatoma cell lines despite clinical outcome with AR treatment and the L3 fraction of AFP. Even though the dramatic decrease in AFP is the limiting factor in the synthesis of the L3 fraction and, therefore, the absolute value of fucosylated AFP is extremely low, the conversion from L1 to L3 as judged by lectin immunoelectrophoresis represents a good marker for the progress of AR treatment.

Analysis of apoptotic and antiapoptotic signalling pathways induced by Helicobacter pylori

BACKGROUND AND AIMS

Although it is reported that Helicobacter pylori induces apoptosis on gastric epithelial cells, the mechanism remains unknown. Antiapoptotic effects generated by H pylori have not yet been evaluated.

METHODS

(1) H pylori strains (type 1 wild, TN2-DeltacagE, TN2-DeltavacA) were cocultured with MKN45, TMK1, and HeLa cells, and cell viability and apoptosis were assessed by trypan blue exclusion and DNA laddering, respectively. (2) Activation of caspases-3, 7, and 8, cytochrome c release from the mitochondria, and Fas, Fas associated death domain protein (FADD), Bax, Bak, and Bcl-X expression were evaluated by immunoblot analysis. (3) To investigate whether nuclear factor kappa B (NFkappaB) activation induced by cag pathogenicity island (PAI) positive H pylori affects antiapoptosis, MKN45 cells stably expressing super-repressor Ikappabetaalpha were cocultured with H pylori, and cell viability and caspase activation were evaluated. NFkappaB regulated gene expression was also evaluated by ribonuclease protection assay.

RESULTS

(1) Wild-type and DeltavacA mutant H pylori induced apoptosis more potently than the DeltacagE mutant. Inhibition of cell contact between H pylori and cancer cells and heat killing H pylori diminished cell death. (2) Caspases-3, 7, and 8 were activated time dependently by H pylori as well as by the agonist anti-Fas. Cytochrome c release from mitochondria was observed and was not inhibited by caspase-8 inhibitor. Although protein expression of Fas, FADD, Bax, Bak, and Bcl-X in the whole cell lysates was not changed by H pylori, Bax was decreased from mitochondria free cytosol suggesting that Bax was translocated into mitochondria. (3) Cell death and the activities of caspases-3 and 8 were promoted in MKN45 cells stably expressing super-repressor Ikappabetaalpha that inhibits NFkappaB activation. Antiapoptotic proteins c-IAP1 and c-IAP2 were upregulated by the wild-type strains.

CONCLUSION

cag PAI positive H pylori is capable of inducing apoptotic effects mainly through the mitochondrial pathway. Antiapoptotic effects mediated by NFkappaB activation were also observed.

Weak response of helicobacter pylori antibody is high risk for gastric cancer: a cross-sectional study of 10,234 endoscoped Japanese

BACKGROUND

A large number of endoscoped members of the general Japanese population were surveyed to investigate the relationship between Helicobacter pylori infection and gastric cancer. Special attention was given to antibody titer and age of the subjects.

METHODS

We performed gastrointestinal endoscopy and measured serum anti-H. pylori antibody in 10,234 consecutive Japanese who participated in a health examination program. Gastric cancer, when suspected, was confirmed by histology. We graded the H. pylori antibody titer into three groups in accordance with optical density values by ELISA: 'strongly positive', 'weakly positive', and 'negative'.

RESULTS

Among the 10,234 subjects (men/women, 7.021/3,213; mean age, 49.1 years), 4,909 (48%) were strongly positive, 1,750 (17%) were weakly positive, and 3,575 (35%) were negative for H. pylori antibody. Thirty-seven cases of gastric cancer were found among the 10,234 subjects (0.36%); 23/4,909 (0.47%) in the strongly positive group, 9/1,750 (0.51%) in the weakly positive group, and 5/3,575 (0.14%) in the negative group. Both the strongly and weakly positive groups showed a higher risk of gastric cancer than the negative group. In the subjects over age 60, the weakly positive group seemed to show the highest risk for gastric cancer.

CONCLUSIONS

In this investigation of 10,234 Japanese, based on endoscopy results, those with serum H. pylori antibody had an increased risk for gastric cancer, while those 'weakly positive' showed a high risk, particularly in the elderly.

Extensive mesenteric vein and portal vein thrombosis successfully treated by thrombolysis and anticoagulation

Mesenteric vein thrombosis is generally difficult to diagnose and can be fatal. A case of extensive thrombosis of the mesenteric and portal veins was diagnosed early and successfully treated in a 26-year-old man with Down syndrome who was admitted to hospital because of abdominal pain, severe nausea and high fever. Ultrasonography revealed moderate ascites, and there was minimal flow in the portal vein (PV) on the Doppler examination. Computed tomography (CT) showed remarkable thickening of the walls of the small intestine and extensive thrombosis of the mesenteric, portal and splenic veins. Because neither intestinal infarction nor peritonitis was seen, combined thrombolysis and anticoagulation therapy without surgical treatment was chosen. Urokinase was administered intravenously and later through a catheter in the superior mesenteric artery. Heparin and antibiotics were given concomitantly. The patient's symptoms and clinical data improved gradually. After 10 days, CT revealed that collateral veins had developed and the thrombi in the distal portions of the mesenteric veins had dissolved, although the main trunk of the PV had not recanalized. The only risk factor of thrombosis that was detected was decreased protein S activity.

Distinct mechanism of Helicobacter pylori-mediated NF-kappa B activation between gastric cancer cells and monocytic cells

NF-kappaB is a critical regulator of genes involved in inflammation. Gastric epithelial cells and macrophages are considered the main sources of pro-inflammatory cytokines. We investigated NF-kappaB activation by Helicobacter pylori in MKN45 gastric epithelial cells and THP-1 monocytic cells. Although, cag pathogenicity island (PAI)-positive H. pylori (wild type) activated NF-kappaB in both cells, isogenic mutant of cagE (DeltacagE) activated it only in THP-1 cells. Supernatant from the wild type culture could activate NF-kappaB in THP-1 cells but not in MKN45 cells. High density cDNA array analysis revealed that mRNA expression of NF-kappaB-regulated genes such as interleukin (IL)-8, tumor necrosis factor-alpha (TNFalpha), and IL-1beta was significantly up-regulated by the wild type in both cells, whereas it was up-regulated by DeltacagE only in THP-1 cells. Experiments using CD14-neutralizing antibody and IL-1 receptor-associated kinase (IRAK) assay showed that both wild type and DeltacagE H. pylori activated NF-kappaB through CD14 and IRAK in THP-1 cells but not in MKN45 cells. Macrophages from C3H/HeJ mice carrying point mutation in the Toll-like receptor 4 (TLR4) gene showed decreased NF-kappaB activation and TNFalpha secretion compared with C3H/HeN mouse macrophage when treated with H. pylori. In conclusion, H. pylori-induced NF-kappaB activation in epithelial cells is dependent on cag PAI and contact but does not involve CD14 and IRAK, whereas in macrophage/monocytic cells it is independent of cag PAI or contact but involves CD14 and TLR4.