Melanoma and microbiota: Current understanding and future directions

Over the last decade, the composition of the gut microbiota has been found to correlate with the outcomes of cancer patients treated with immunotherapy. Accumulating evidence points to the various mechanisms by which intestinal bacteria act on distal tumors and how to harness this complex ecosystem to circumvent primary resistance to immune checkpoint inhibitors. Here, we review the state of the microbiota field in the context of melanoma, the recent breakthroughs in defining microbial modes of action, and how to modulate the microbiota to enhance response to cancer immunotherapy. The host-microbe interaction may be deciphered by the use of "omics" technologies, and will guide patient stratification and the development of microbiota-centered interventions. Efforts needed to advance the field and current gaps of knowledge are also discussed.

Inhibition of novel lipoprotein(a) receptor major facilitator superfamily domain containing 5 (MFSD5) reduces development of aortic valve calcification

Funding Acknowledgements

Type of funding sources: Other. Main funding source(s): Private grant from Kowa Pharmaceuticals to Brigham and Woman's Hospital

Calcific aortic valve stenosis (CAVS) is the most prevent valvular heart disease in the western world increasing exponentially with age, with an 112% increase in CAVS deaths in the last three decades; however no therapeutic treatment is currently available. Recently, lipoprotein(a) [Lp(a)] has been demonstrated to be an independent and causal risk factor for CAVS, yet the understanding of its cellular uptake and catabolism is limited thus underscoring the need for further investigation.

This study aimed to determine a target receptor, unique for Lp(a) on the surface of valvular interstitial cells (VICs) and ascertain the role of the receptor on the development of VIC calcification.

Unbiased ligand-receptor capture mass spectrometry (TriCEPS) was used to identify target receptor, with western blotting, ELISA, qPCR, alizarin red calcium staining and immunofluorescence used to validate the targets in vitro via siRNA inhibition and overexpression. Transmission electron microscopy (TEM) was used to determine uptake of Lp(a) within excised human valves. Identification of small molecule inhibitors was assessed computationally via the L1000 dataset, with the top hit candidate validated in vitro. Genotype-phenotype studies were examined using the United Kingdom Biobank (UKBB) and the Millions Veterans Program. Linear regression was used to evaluate association between aortic stenosis and plasma Lp(a) levels, and a phenotype-wide association analysis was then performed against this generated ‘genotype’.

Ligand-receptor capture mass spectrometry was used to detect novel membrane proteins with specific binding to Lp(a); MFSD5, MRC2, LDLR were identified as possible candidates. MFSD5 RNAscope demonstrated its presence in human aortic valves. Lp(a) uptake in VICs was confirmed via western blot and TEM. MFSD5 siRNA significantly reduced dil-labelled Lp(a) uptake in human VICs (p=0.003) and HEPG2 cells (p=0.0003), conversely MFSD5 overexpression increased uptake (p=0.0345, p=0.0318), whilst specificity of MFSD5 to Lp(a) alone was shown via no change in LDL uptake following MFSD5 inhibition (p=0.616, p=0.991). MFSD5 inhibition reduced RUNX2 (p=0.0124) and Osteocalcin (p<0.001) RNA expression and reduced alizarin red staining following culture in Lp(a) osteogenic media for 21 days (p<0.0033). Druggability of MFSD5 was confirmed by the L1000 database, which identified aminopurvalanol as a binding partner for MFSD5 and significantly reduced Lp(a) uptake within VICs (p=0.0091). MFSD5-loss of function within the UKBB showed no significant cardiovascular association, however 50kb +/- of the MFSD5 gene showed nominal association with hyperlipidaemia and atrial fibrillation.

The current study demonstrates the novel Lp(a) receptor MFSD5 may be responsible for uptake of Lp(a) within VICs, resulting in the development of aortic valve calcification, highlighting the need for further exploration into the role of MFSD5 in aortic valve disease.

A natural history museum visitor survey of perception, attitude and knowledge (PAK) of microbes and antibiotics

A kiosk-based survey at the American Museum of Natural History in New York City in 2016-2018 allowed us to assess public knowledge of antibiotics and public attitudes toward microbes in museum goers. Over 22,000 visitors from 172 countries and territories answered several carefully designed questions about microbes and antibiotics. These visitors also entered age, gender, and country demographic data that allowed for stratification along these demographic and geographic divisions. Because museum goers are likely to be better informed about these and other science-based topics, the results described here can set a potential upper bound for public knowledge on these topics. Surprisingly, the results of our analysis of museum goers' answers about microbes and antibiotics indicate a substantial lack of familiarity with both topics. For example, overall only about 50% of respondents can correctly identify penicillin as an antibiotic and less than 50% of museum visitors view microbes as beneficial. The results described here suggest that we are perhaps off target with our educational efforts in this area and that a major shift in approach toward more basic microbial topics is warranted in our educational efforts.

Next steps in studying the human microbiome and health in prospective studies, Bethesda, MD, May 16-17, 2017

The National Cancer Institute (NCI) sponsored a 2-day workshop, "Next Steps in Studying the Human Microbiome and Health in Prospective Studies," in Bethesda, Maryland, May 16-17, 2017. The workshop brought together researchers in the field to discuss the challenges of conducting microbiome studies, including study design, collection and processing of samples, bioinformatics and statistical methods, publishing results, and ensuring reproducibility of published results. The presenters emphasized the great potential of microbiome research in understanding the etiology of cancer. This report summarizes the workshop and presents practical suggestions for conducting microbiome studies, from workshop presenters, moderators, and participants.

Abstract 5: The Contribution of Microbiome Alterations to Atherosclerotic Plaque Regression in Mice

Objective: The human microbiome represents an underexplored driver of atherosclerosis. Alterations to the intestinal microbiome are associated with, systemic inflammation and upregulation of M1 macrophages (Mϕ). Our study aims to determine if alterations to the intestinal microbiome by antibiotic treatment interferes with atherosclerotic plaque regression in mice.

Methods: ApoE -/- mice were fed a western diet for 16 weeks to develop complex atherosclerosis in aortic arches. These arches were transplanted into the abdominal aorta of wild-type (WT) mice to model clinical aggressive lipid management and promote plaque regression. To assess the contribution of the microbiome to plaque regression, aortic arches were transplanted in WT mice (n=4), and WT mice pulsed with tylosin (antibiotic, n = 4) 3 days pre-transplant and the duration of the experiment (5 days). Arches were also transplanted into ApoE -/- mice as a plaque progression control (n =4).

Results: Antibiotic treatment of WT mice with tylosin compared to control WT mice did not change circulating total cholesterol (TC, 57 ± 21 mg/dl vs. 46 ± 24 mg/dl, p = 0.5), or HDL-C (42 ± 8 mg/dl vs. 34 ± 11 mg/dl, p = 0.32). No statistically significant difference in plaque size (117,801 ± 70,921 μm 2 vs. 133,286 ± 19,871 μm 2 vs. 132,976 ± 40,347 μm 2 , p = 0.88) or the absolute Mϕ content (44,672 ± 27,154 μm 2 vs. 32,546 ± 21,226 μm 2 vs. 54,154 ± 22,418 μm 2 , p = 0.47) was observed in WT mice which received tylosin, compared to control WT and ApoE -/- mice, respectively. The composition of the plaques however did change: When compared to the control ApoE -/- mice, WT recipient mice had a 26% reduction in the percent of the plaques occupied by Mϕ, while WT mice receiving tylosin had only a 4% reduction (p = 0.07). There was a 20% difference between the percent of plaque Mϕ content in the WT receiving tylosin, compared to WT controls (38% ± 4.3 vs. 30% ± 6.2, p = 0.07).

Conclusion: Tylosin-treated WT mice undergoing regression had Mϕ enrichment in their plaques compared to WT controls. This study suggests that microbiome alterations can negatively influence plaque regression. Intestinal microbiome analysis and further studies are needed to confirm and extend this finding.

Effect of weir impoundments on methane dynamics in a river

We measured CH₄ concentration, CH₄ oxidation in the water column and total CH₄ emissions to the atmosphere (diffusion and ebullition) in three weir impoundments and river reaches between them, in order to understand their role in river methane (CH₄) dynamics. Sediment samples were also collected to determine CH₄ consumption and production potentials together with the contribution of individual methanogenic pathways. The CH₄ surface water concentration increased 7.5 times in the 16km long river stretch. Microbial CH₄ oxidation in the water column reached values ranging from 51 to 403nmoll^-1d^-1 and substantially contributed to the CH₄ removal from surface water, together with CH₄ emissions. The total CH₄ emissions to the atmosphere varied between 0.8 and 207.1mmolCH₄m^-2d^-1 with the highest values observed upstream of the weirs (mean 68.5±29.9mmolCH₄m^-2d^-1). Most of the CH₄ was transported through the air-water interface by ebullition upstream of the weirs, while the ebullition accounted for 95.8±2.0% of the total CH₄ emissions. Both CH₄ production and oxidation potential of sediments were higher upstream of the weirs compared to downstream of the weirs. The contribution of hydrogenotrophic methanogenesis to total CH₄ sediment production was 36.7-89.4% and prevailed upstream of the weirs. Our findings indicate that weirs might influence river CH₄ dynamics, especially by increased CH₄ production and consumption by sediments, followed by increasing CH₄ emissions to the atmosphere.

Is the methanogenic community reflecting the methane emissions of river sediments?-comparison of two study sites

Studies on methanogenesis from freshwater sediments have so far primarily focused on lake sediments. To expand our knowledge on the community composition of methanogenic archaea in river sediments, we studied the abundance and diversity of methanogenic archaea at two localities along a vertical profile (top 50 cm) obtained from sediment samples from Sitka stream (the Czech Republic). In this study, we compare two sites which previously have been shown to have a 10‐fold different methane emission. Archaeal and methanogen abundance were analyzed by real‐time PCR and T‐RFLP. Our results show that the absolute numbers for the methanogenic community (qPCR) are relatively stable along a vertical profile as well as for both study sites. This was also true for the archaeal community and for the three major methanogenic orders in our samples (Methanosarcinales, Methanomicrobiales, and Methanobacteriales). However, the underlying community structure (T‐RFLP) reveals different community compositions of the methanogens for both locations as well as for different depth layers and over different sampling times. In general, our data confirm that Methanosarcinales together with Methanomicrobiales are the two dominant methanogenic orders in river sediments, while members of Methanobacteriales contribute a smaller community and Methanocellales are only rarely present in this sediment. Our results show that the previously observed 10‐fold difference in methane emission of the two sites could not be explained by molecular methods alone.

Carbon Isotope Fractionation during Catabolism and Anabolism in Acetogenic Bacteria Growing on Different Substrates

Homoacetogenic bacteria are versatile microbes that use the acetyl coenzyme A (acetyl-CoA) pathway to synthesize acetate from CO2 and hydrogen. Likewise, the acetyl-CoA pathway may be used to incorporate other 1-carbon substrates (e.g., methanol or formate) into acetate or to homoferment monosaccharides completely to acetate. In this study, we analyzed the fractionation of pure acetogenic cultures grown on different carbon substrates. While the fractionation of Sporomusa sphaeroides grown on C1 compounds was strong (εC1, -49‰ to -64‰), the fractionation of Moorella thermoacetica and Thermoanaerobacter kivui using glucose (εGlu= -14.1‰) was roughly one-third as strong, suggesting a contribution of less-depleted acetate from fermentative processes. ForM. thermoacetica, this could indeed be validated by the addition of nitrate, which inhibited the acetyl-CoA pathway, resulting in fractionation during fermentation (εferm= -0.4‰). In addition, we determined the fractionation into microbial biomass of T. kivui grown on H2/CO2(εanabol.= -28.6‰) as well as on glucose (εanabol.= +2.9‰).

Dynamics of intestinal IgA expression after early-life antibiotic treatment. (MUC9P.738)

Class IgA secretory antibodies (SigA) are an early line of antigen-specific immune defenses that are influenced by commensal microbial populations. Perinatal antibiotic exposures may affect the host microbiota and have long-term consequences on host immunity. We hypothesize that early-life pulsed antibiotic treatment (PAT) perturbs the intestinal microbiota leading to alterations in sIgA expression. To test this hypothesis, C57BL/6 mice were exposed to 5 therapeutic doses of the β-lactam, amoxicillin, or the macrolide, tylosin. Exposure to either the tylosin or amoxicillin delayed sIgA expression. sIgA expression recovered in β-lactam-exposed mice but was abrogated with macrolide exposure. Compared to age-matched controls, 1 or 3 tylosin pulses decreased sIgA levels by 40% and 75%, respectively. Alterations in sIgA production were associated with decreased bacterial richness (α-diversity), altered community structure (β-diversity), and changes in microbial compositional, including increased abundance of Enterobacteriaceae and Bacteroides uniformis. Whereas tylosin had multiple immunological effects on conventional mice, essentially none were detected in germ-free animals; indicating that an antibiotic-perturbed microbiota influences developing immunity. These results provide evidence that early-life alterations of the intestinal microbiota by PAT modulates sIgA production, phenotypes that may persist after microbial recovery, with long-term consequences to host immunity.

Helsinki alert of biodiversity and health

Urban living in built environments, combined with the use of processed water and food, may not provide the microbial stimulation necessary for a balanced development of immune function. Many chronic inflammatory disorders, including allergic, autoimmune, metabolic, and even some behavioural disorders, are linked to alteration in the human commensal microbiota. Sedentary lifestyle is associated with reduced exposure to a broad spectrum of environmental micro-organisms and surplus energy balance, both risk factors of chronic inflammatory disorders. According to the Biodiversity Hypothesis, an environment with diverse macrobiota and microbiota modifies and enriches the human microbiota, which in turn is crucial in the development and maintenance of appropriate immune function. These issues were discussed in the symposium 'Chronic Inflammation, Lifestyle and Environment', held in Helsinki, 20-22 August 2014, under the sponsorship of the Yrjö Jahnsson Foundation. This paper briefly outlines the recent findings in the context of the environment, lifestyle, and health; discusses the forces that undermine immune tolerance in urban environments; and highlights the possibilities to restore broken immune tolerance among urban dwellers, summarizing the main messages in four statements and calling for actions to combat major public health threats.

Understanding the effect of early-life pulsed antibiotic treatment on mucosal T-lymphocyte populations (MUC4P.827)

Broad-spectrum antibiotics are frequently prescribed for children. The gut microbiota have functional roles in the development and differentiation of the host immune system. Early-life antibiotic use may have dynamic effects on the host microbiota, promoting long-term immunologic dysregulation and subsequent allergic and autoimmune pathology. Using a model of early-life antibiotic use, we hypothesize that early-life pulsed antibiotic treatment (PAT) -induced perturbation of the intestinal microbiota leads to alterations in tissue-specific and systemic T-cell populations. To test this hypothesis, we characterized splenic and ileal T-cell populations in control and PAT-treated C57BL/6 mice. Flow cytometric analysis demonstrated that early-life PAT significantly (p<0.05) decreased the frequency of splenic CD4+ and CD8+ T-cells and ileal CD4+ IL-17A+ Th17 populations. In contrast, ileal CD4+ Tbet+ (Th1) T cells and CD4+ Foxp3+ regulatory T-cell populations were significantly increased in PAT-treated mice. Alterations in immune cell populations were associated with microbial compositional changes, including significantly higher relative abundance of Enterobacteriaceae and Akkermansia muciniphila in PAT-treated mice. These results provide evidence that early-life perturbation of the intestinal microbiota by PAT modulates systemic and mucosal T-cell populations, phenotypes that may persist after microbial recovery, promoting life-long consequences to host immunity.

Probiotics, prebiotics, and the host microbiome: the science of translation

Recent advances in our understanding of the community structure and function of the human microbiome have implications for the potential role of probiotics and prebiotics in promoting human health. A group of experts recently met to review the latest advances in microbiota/microbiome research and discuss the implications for development of probiotics and prebiotics, primarily as they relate to effects mediated via the intestine. The goals of the meeting were to share recent advances in research on the microbiota, microbiome, probiotics, and prebiotics, and to discuss these findings in the contexts of regulatory barriers, evolving healthcare environments, and potential effects on a variety of health topics, including the development of obesity and diabetes; the long-term consequences of exposure to antibiotics early in life to the gastrointestinal (GI) microbiota; lactose intolerance; and the relationship between the GI microbiota and the central nervous system, with implications for depression, cognition, satiety, and mental health for people living in developed and developing countries. This report provides an overview of these discussions.

Stable carbon isotope fractionation by methylotrophic methanogenic archaea

In natural environments methane is usually produced by aceticlastic and hydrogenotrophic methanogenic archaea. However, some methanogens can use C(1) compounds such as methanol as the substrate. To determine the contributions of individual substrates to methane production, the stable-isotope values of the substrates and the released methane are often used. Additional information can be obtained by using selective inhibitors (e.g., methyl fluoride, a selective inhibitor of acetoclastic methanogenesis). We studied stable carbon isotope fractionation during the conversion of methanol to methane in Methanosarcina acetivorans, Methanosarcina barkeri, and Methanolobus zinderi and generally found large fractionation factors (-83‰ to -72‰). We further tested whether methyl fluoride impairs methylotrophic methanogenesis. Our experiments showed that even though a slight inhibition occurred, the carbon isotope fractionation was not affected. Therefore, the production of isotopically light methane observed in the presence of methyl fluoride may be due to the strong fractionation by methylotrophic methanogens and not only by hydrogenotrophic methanogens as previously assumed.

Abstract A107: Esophageal and stomach cancer trends by race, gender, subsite, and histology

Background: Esophageal, gastric and gastroesophageal (GE) junction carcinomas have clearly had different trends of incidence over the the past two decades in the world, especially in the United States. What is more alarming is the histological type of subsite cancer appears to be changing and may also differ according to ethnicity and gender as well. The authors examined incidence patterns among Caucasians (C), African Americans (AA) and Asian/Pacific Islanders (API).

Methods: We used data from the Surveillance Epidemiology and End Results (SEER) database of the National Cancer Institute. SEER 9 data was used to identify all patients who were diagnosed with esophageal, stomach and GE junction carcinomas between 1975 and 2006. Age-adjusted rates and age specific rates were computed by anatomic subsite, histology, race, and gender. Incidence trend patterns were analyzed accordingly.

Results: Major differences were seen for the distribution of esophageal cancer based on subsite, histology and ethnicity. White males had the predominant histology adenocarcinoma in the distal esophagus (83.9%) compared to AA having squamous cell carcinoma (63.8%) and API having similar distribution of both adenocarcinoma (43.6%) and squamous (48%). This trend was not seen in white females. In Caucasian men, adenocarcinoma of the distal esophagus is now outnumbering adenocarcinoma of the stomach. This trend is not seen in any other ethnic and/or gender group. For stomach cancer, white males had more proximal tumors compared to black males. Black males were diagnosed with distal tumors compared to white males.

Conclusions: There are large differences in incidence trends according to ethnicity, gender, anatomic subsite and histology. The variation in cancer incidence patterns by race does not seem to be completely explained or accounted for by differences in known risk factors.

Citation Information: Cancer Epidemiol Biomarkers Prev 2010;19(10 Suppl):A107.

Genetic variation in a4GnT in relation to Helicobacter pylori serology and gastric cancer risk

BACKGROUND

Helicobacter pylori, a known risk factor of gastric cancer, rarely colonize the deeper portion of normal gastric glands, where the mucus is rich in alpha-1,4-linked N-acetylglucosamine capped O-glycans, that strongly inhibit H. pylori growth in vitro.

MATERIALS AND METHODS

We investigated the association between genetic variation in the O-glycan transferase encoding gene (a4GnT) and H. pylori infection and gastric cancer risk using a Polish population-based case-control study (273 gastric cancer patients and 377 controls).

RESULTS

A haplotype at the rs2622694-rs397266 locus was associated with H. pylori infection, with the A-A haplotype associated with a higher risk compared with the most frequent G-G haplotype (odds ratio 2.30; 95% confidence interval 1.35-3.92). The association remained significant after correction for multiple tests (global p value: nominal 0.002, empirical 0.045). Neither this haplotype nor the tagSNPs were associated with overall gastric cancer risk.

CONCLUSION

a4GnT genetic variation may be relevant to H. pylori infection, but not to gastric cancer risk.

4-Hydroxyphenylacetate Decarboxylases: Properties of a Novel Subclass of Glycyl Radical Enzyme Systems†

The 4-hydroxyphenylacetate decarboxylases from Clostridium difficile and Clostridium scatologenes, which catalyze the formation of p-cresol, form a distinct group of glycyl radical enzymes (GREs). Cresol formation provides metabolic toxicity, which allows an active suppression of other microbes and may provide growth advantages for the producers in highly competitive environments. The GRE decarboxylases are characterized by a small subunit, which is not similar to any protein of known function in the databases, and provides unique properties that have not been observed in other GREs. Both decarboxylases are functional hetero-octamers (beta(4)gamma(4)), which contain iron-sulfur centers in addition to the glycyl radical prosthetic group. The small subunit is responsible for metal binding and is also involved in the regulation of the enzymes' oligomeric state and activity, which are triggered by reversible serine phosphorylation of the glycyl radical subunits. Biochemical data suggest that the iron-sulfur centers of the decarboxylases could be involved in the radical dissipation of previously activated enzymes in the absence of substrate. The cognate activating enzymes differ from their Pfl and Nrd counterparts in that up to two iron-sulfur centers, in addition to the characteristic SAM cluster, were found. Biochemical data suggested that these [4Fe-4S] centers are involved in the electron transfer to the SAM cluster but do not directly participate in the reductive cleavage of SAM. These data imply a tight regulation of p-cresol formation, which is necessary in order to avoid detrimental effects of the toxic product on the producers.

Determinants of virulence for the parasite Nosema whitei in its host Tribolium castaneum

For many parasites, especially those that obligately kill the host for transmission, host age is crucially important to determine success. Here, we have experimentally investigated this relationship with the microsporidian parasite, Nosema whitei, in its host, the Red Flour Beetle, Tribolium castaneum. We find that infection is only possible in young larvae and that spore load at the time of transmission (i.e., host death) correlates with host body size. The data suggested that an infection by N. whitei prolongs the life span of the infected larva and prevents them from pupation. Together, virulence to the host and success for the parasite is mainly determined by the host age at infection. The patterns are consistent with theoretical predictions for obligate killer parasites.

Infectious agents and cancer: criteria for a causal relation

Infectious agents, mainly viruses, are among the few known causes of cancer and contribute to a variety of malignancies worldwide. The agents and cancers considered here are human papillomaviruses (cervical carcinoma); human polyomaviruses (mesotheliomas, brain tumors); Epstein-Barr virus (B-cell lymphoproliferative diseases and nasopharyngeal carcinoma); Kaposi's Sarcoma Herpesvirus (Kaposi's Sarcoma and primary effusion lymphomas); hepatitis B and hepatitis C viruses (hepatocellular carcinoma); Human T-cell Leukemia Virus-1 (T-cell leukemias); and helicobacter pylori (gastric carcinoma), which account for up to 20% of malignancies around the globe. The criteria most often used in determining causality are consistency of the association, either epidemiologic or on the molecular level, and oncogenicity of the agent in animal models or cell cultures. However use of these generally applied criteria in deciding on causality is selective, and the criteria may be weighted differently. Whereas for most of the tumor viruses the viral genome persists in an integrated or episomal form with a subset of viral genes expressed in the tumor cells, some agents (HBV, HCV, helicobacter) are not inherently oncogenic, but infection leads to transformation of cells by indirect means. For some malignancies the viral agent appears to serve as a cofactor (Burkitt's lymphoma-EBV; mesothelioma - SV(40)). For others the association is inconsistent (Hodgkin's Disease, gastric carcinomas, breast cancer-EBV) and may either define subsets of these malignancies, or the virus may act to modify phenotype of an established tumor, contributing to tumor progression rather than causing the tumor. In these cases and for the human polyomaviruses the association with malignancy is less consistent or still emerging. In contrast despite the potent oncogenic properties of some strains of human adenovirus in tissue culture and animals the virus has not been linked with any human cancers. Finally it is likely that more agents, most likely viruses, both known and unidentified, have yet to be implicated in human cancer. In the meantime study of tumorigenic infectious agents will continue to illuminate molecular oncogenic processes.

Distinguishing human ethnic groups by means of sequences from Helicobacter pylori: lessons from Ladakh

The history of mankind remains one of the most challenging fields of study. However, the emergence of anatomically modern humans has been so recent that only a few genetically informative polymorphisms have accumulated. Here, we show that DNA sequences from Helicobacter pylori, a bacterium that colonizes the stomachs of most humans and is usually transmitted within families, can distinguish between closely related human populations and are superior in this respect to classical human genetic markers. H. pylori from Buddhists and Muslims, the two major ethnic communities in Ladakh (India), differ in their population-genetic structure. Moreover, the prokaryotic diversity is consistent with the Buddhists having arisen from an introgression of Tibetan speakers into an ancient Ladakhi population. H. pylori from Muslims contain a much stronger ancestral Ladakhi component, except for several isolates with an Indo-European signature, probably reflecting genetic flux from the Near East. These signatures in H. pylori sequences are congruent with the recent history of population movements in Ladakh, whereas similar signatures in human microsatellites or mtDNA were only marginally significant. H. pylori sequence analysis has the potential to become an important tool for unraveling short-term genetic changes in human populations.

Population attributable risks of esophageal and gastric cancers

BACKGROUND

Several risk factors have been identified for esophageal adenocarcinoma, gastric cardia adenocarcinoma, esophageal squamous cell carcinoma, and noncardia gastric adenocarcinoma, but no study has comprehensively examined their contributions to the cancer burden in the general population. Herein, we estimate the population attributable risks (PARs) for various risk factors observed in a multicenter population-based case-control study.

METHODS

We calculated PARs by using 293 patients with esophageal adenocarcinoma, 261 with gastric cardia adenocarcinoma, 221 with esophageal squamous cell carcinoma, 368 with noncardia gastric adenocarcinoma, and 695 control subjects. We included smoking for all four tumor types and Helicobacter pylori infection for noncardia gastric adenocarcinoma as established causal risk factors as well as several other factors for which causality is under evaluation.

RESULTS

Ever smoking, body mass index above the lowest quartile, history of gastroesophageal reflux, and low fruit and vegetable consumption accounted for 39.7% (95% confidence interval [CI] = 25.6% to 55.8%), 41.1% (95% CI = 23.8% to 60.9%), 29.7% (95% CI = 19.5% to 42.3%), and 15.3% (95% CI = 5.8% to 34.6%) of esophageal adenocarcinomas, respectively, with a combined PAR of 78.7% (95% CI = 66.5% to 87.3%). Ever smoking and body mass index above the lowest quartile were responsible for 45.2% (95% CI = 31.3% to 59.9%) and 19.2% (95% CI = 4.9% to 52.0%) of gastric cardia adenocarcinomas, respectively, with a combined PAR of 56.2% (95% CI = 38.1% to 72.8%). Ever smoking, alcohol consumption, and low fruit and vegetable consumption accounted for 56.9% (95% CI = 36.6% to 75.1%), 72.4% (95% CI = 53.3% to 85.8%), and 28.7% (95% CI = 11.1% to 56.5%) of esophageal squamous cell carcinomas, respectively, with a combined PAR of 89.4% (95% CI = 79.1% to 95.0%). Ever smoking, history of gastric ulcers, nitrite intake above the lowest quartile, and H. pylori infection were responsible for 18.3% (95% CI = 6.5% to 41.8%), 9.7% (95% CI = 5.4% to 16.8%), 40.7% (95% CI = 23.4% to 60.7%), and 10.4% (95% CI = 0.3% to 79.6%) of noncardia gastric adenocarcinomas, respectively, with a combined PAR of 59.0% (95% CI = 16.2% to 91.4%).

CONCLUSION

In this population, a few known risk factors account for a majority of esophageal and gastric cancers. These results suggest that the incidence of these cancers may be decreased by reducing the prevalence of smoking, gastroesophageal reflux, and being overweight and by increasing the consumption of fruits and vegetables.

Cutaneous anthrax associated with microangiopathic hemolytic anemia and coagulopathy in a 7-month-old infant

A 7-month-old infant with cutaneous anthrax developed severe systemic illness despite early treatment with antibiotics. The infant displayed severe microangiopathic hemolytic anemia with renal involvement, coagulopathy, and hyponatremia. These findings are unusual with cutaneous anthrax, but have been described in illness resulting from spider toxin and may delay correct diagnosis. The systemic manifestations of the disease persisted for nearly a month despite corticosteroid therapy, but resolved.

Helicobacter pylori seropositivity and subsite-specific gastric cancer risks in Linxian, China

BACKGROUND

Helicobacter pylori carriage (i.e., persistent exposure to the organism without gastric epithelial cell invasion) is an established risk factor for noncardia gastric cancer. However, its association with the risk of cancer of the gastric cardia is controversial. Consequently, we designed this prospective, nested case-control study to further explore the subsite-specific gastric cancer risks associated with H. pylori seropositivity (a surrogate marker for persistent exposure).

METHODS

A total of 99 patients with gastric cardia cancer, 82 patients with noncardia gastric cancer, and 192 cancer-free subjects were selected from among the participants (n = 29 584) of a nutrition intervention trial previously conducted in Linxian, China. H. pylori seropositivity was determined by assaying for the presence of H. pylori whole cell and CagA antibodies in baseline serum samples from all subjects. Seropositivity was defined as one or both serum assays being positive. Odds ratios (ORs) for subsite-specific gastric cancer were estimated by multivariate logistic regression analyses. All statistical comparisons were two-sided (alpha =.05).

RESULTS

H. pylori seropositivity rates for subjects with gastric cardia cancer, noncardia gastric cancer, and gastric cardia and noncardia cancers combined were 70% (P =.02), 72% (P: =.01), and 71% (P =.003) compared with 56% for cancer-free control subjects. OR estimates for H. pylori seropositivity were 1.87 (95% confidence interval [CI] = 1.10 to 3.17) for gastric cardia cancer, 2.29 (95% CI = 1.26 to 4.14) for noncardia gastric cancer, and 2.04 (95% CI = 1.31 to 3.18) for gastric cardia and noncardia cancers combined.

CONCLUSIONS

H. pylori seropositivity was associated with increased risks for both gastric cardia cancer and noncardia gastric cancer in this well-characterized cohort. Thus, H. pylori carriage may increase the risk of cancer throughout the stomach.

Thermophilic multidrug-resistant Campylobacter fetus infection with hypersplenism and histiocytic phagocytosis in a patient with acquired immunodeficiency syndrome

We present a case report of a patient who had acquired immunodeficiency syndrome (AIDS) and Campylobacter fetus infection with a number of unusual clinical and microbiological features. The patient had prominent gastrointestinal symptoms, splenic infarction, splenomegaly with hypersplenism, and hemophagocytic histiocytosis in the spleen and lymph nodes; the organism displayed growth on Campy-selective blood agar, thermotolerance, and resistance to quinolones, piperacillin/tazobactam, ceftazidime, and erythromycin.

A controlled trial of methylprednisolone in the early emergency department treatment of acute asthma in children

Asthma continues to be a leading cause for pediatric hospitalizations. A study using high-dose intravenous (i.v.) steroids early in the emergency department (ED) care of adults with acute asthma reported a 60% reduction in hospitalization rate. Limited data are available for children. We hypothesized that the addition of early administration of high-dose methylprednisolone (MP) in routine ED care of asthmatic children would reduce the need for hospitalization by 50%. Eighty-eight children with asthma, aged four to 18 years, were enrolled into a prospective, randomized, double-blind, placebo-controlled study of MP given within 45 (mean 23) minutes of arrival to the ED. After initial evaluation, children received either 2 mg/kg of MP IV or an equivalent amount of placebo (P). Patients then received the usual ED management of their acute exacerbation. Groups were similar in age, sex, and severity of illness (by asthma scoring, respiratory rate, and peak flow). ED treatment (number of aerosols and the use of theophylline) was similar for both groups. The mean time to disposition was 2.9 hours. Sixty-four percent of the children were discharged from the ED. No significant differences were found between the admission rates of the MP and P groups (41% MP vs 33% P, P = 0.44, chi 2, 95% CI for decrease in MP vs P groups -28 to +12%). The average hospital stay was shorter for those children treated with MP (79 hours vs 90 hours). We conclude that IV methylprednisolone given as an adjunct to routine ED care of children with acute asthma is unlikely to markedly reduce hospitalization rates.

Seroprevalence of Helicobacter pylori infection is not increased in pediatric inflammatory arthritides

OBJECTIVE

To determine the seroprevalence of H. pylori infection among children with inflammatory arthritides receiving antiinflammatory drug therapy.

METHODS

An enzyme linked immunosorbent assay (ELISA) was used to detect H. pylori specific immunoglobulin G antibody in 95 children with inflammatory arthritides, 53 children with chronic inflammatory bowel diseases and 47 parents of children with inflammatory arthritis.

RESULTS

The frequency of seropositivity in children with arthritis (9/95, 9.5%) was not significantly higher than in children with chronic inflammatory bowel diseases (1/53, 1.9%; p = 0.16). Serum samples from parents were positive in 16 of 47 (34%), including 4 parents with children who also demonstrated a positive immune response.

CONCLUSION

These data do not provide evidence for an increased frequency of H. pylori infection among children with inflammatory arthritides. The therapeutic use of ulcerogenic medications is likely to be an independent risk factor predisposing to dyspeptic symptoms and gastritis in this patient population.

Clinical comparison of systemic methylprednisolone acetate versus topical budesonide in patients with seasonal allergic rhinitis

Thirty patients with seasonal allergic rhinitis entered a double blind study comparing budesonide (nasal spray, 400 micrograms/d) and i.m. injection of 80 mg methylprednisolone acetate. Symptoms were assessed over a "run in" period of 3-7 days followed by a treatment period of 3 weeks. Pollen counts were evaluated daily. Both the systemic and topical corticosteroid treatment resulted in a significant improvement of nasal and ocular symptoms and were accompanied by reduced antihistamine intake. A comparison of the two treatments in relation to the pollen count yielded statistically significantly fewer nasal symptoms, such as itching, secretion, and sneezing in the budesonide-treated group. Nasal blockage and ocular symptoms remained unchanged, but the use of eyedrops was significantly reduced in the methylprednisolone-treated group. Side effects of both treatments were mild and the incidence negligible. Methylprednisolone-treated patients had a significantly lower cortisol value after 7 days but still had a normal response to ACTH-stimulation. We conclude that the acute symptoms of allergic rhinitis are at least as well ameliorated by regular topical application of budesonide as by a single injection of methylprednisolone acetate. The accompanying allergic conjunctivitis may require additional treatment.

Epidemiologic and clinical features of endemic Campylobacter jejuni infection in Bangladesh

Epidemiologic and clinical features of infection with Campylobacter jejuni in Bangladesh were examined in (1) diarrheal patients infected with C jejuni, (2) healthy control subjects, and (3) village children who were cultured monthly and at each diarrheal episode during a 10-month period. C jejuni was isolated from 437 (14%) of 3,038 outpatients with diarrhea. These patients had no distinct clinical presentation and were more likely to have a mixed infection than were patients infected with other pathogens (59% vs 42%, P less than 0.01). Age-specific infection rates were greatest in infants and did not differ significantly from those in control subjects. C jejuni was isolated less frequently from village children with diarrhea than from those cultured routinely (5% vs 9%, P less than 0.05). Forty percent of 47 patients with C jejuni vs 23% of 48 control subjects (P less than 0.01) had an elevated convalescent-phase antibody titer as determined by complement fixation test. In Bangladesh, enteric infection with C jejuni is common but often asymptomatic, although pathogenicity is suggested by serologic response in some patients.