James, S. C., Fraser, K., Cooney, J., Günther, C. S., Young, W., Gearry, R. B., … Keenan, J. I., … Roy, N. C. (2023). Concentrations of plasma amino acids and neurotransmitters in participants with functional gut disorders and healthy controls. Metabolites, 13, 313. doi: 10.3390/metabo13020313

Journal - Research Article

Simon, M. H., Heenan, P. E., Frampton, C., Bayer, S., Keenan, J. I., de Boer, N. K., Roy, N. C., … Gearry, R. B. (2023). Economic living standard and abdominal pain mediate the association between functional gastrointestinal disorders and depression or anxiety. Neurogastroenterology & Motility, 35, e14465. doi: 10.1111/nmo.14465

Journal - Research Article

Thompson, N., Gatenby, G., Waddell, O., Purcell, R., Keenan, J., Pearson, J., Frizelle, F., & Glyn, T. (2023). Early onset colorectal cancer in Canterbury, New Zealand. ANZ Journal of Surgery. Advance online publication. doi: 10.1111/ans.18357

Journal - Research Article

Aitchison, A., Pearson, J. F., Purcell, R. V., Frizelle, F. A., & Keenan, J. I. (2022). Detection of Fusobacterium nucleatum DNA in primary care patient stool samples does not predict progression of colorectal neoplasia. PLoS ONE, 17(6), e0269541. doi: 10.1371/journal.pone.0269541

Journal - Research Article

Ho, S. S. C., Hall, S., Keenan, J. I., & Day, A. S. (2022). Australasian pediatric gastroenterologists' perspectives and practices of Celiac disease diagnosis and management. Digestive Diseases & Sciences, 67, 1744-1752. doi: 10.1007/s10620-021-06988-2

Journal - Research Article

Purcell, R. V., Permain, J., & Keenan, J. I. (2022). Enterotoxigenic Bacteroides fragilis activates IL-8 expression through Stat3 in colorectal cancer cells. Gut Pathogens, 14, 16. doi: 10.1186/s13099-022-00489-x

Journal - Research Article

Edwards, T. S., Dawson, K. L., Keenan, J. I., & Day, A. S. (2021). A simple method to generate β-casomorphin-7 by in vitro digestion of casein from bovine milk. Journal of Functional Foods, 85, 104631. doi: 10.1016/j.jff.2021.104631

Journal - Research Article

Ho, S. S. C., Keenan, J. I., & Day, A. S. (2021). Parent Perspectives of Diagnostic and Monitoring Tests Undertaken by Their Child with Inflammatory Bowel Disease. Pediatric Gastroenterology, Hepatology & Nutrition, 24(1), 19-29. doi: 10.5223/pghn.2021.24.1.19

Journal - Research Article

James, S. C., Fraser, K., Young, W., Heenan, P. E., Gearry, R. B., Keenan, J. I., … Roy, N. C. (2021). Concentrations of fecal bile acids in participants with functional gut disorders and healthy controls. Metabolites, 11, 612.

Journal - Research Article

Aitchison, A., Hakkaart, C., Day, R. C., Morrin, H. R., Frizelle, F. A., & Keenan, J. I. (2020). APC mutations are not confined to hotspot regions in early-onset colorectal cancer. Cancers, 12, 3829. doi: 10.3390/cancers12123829

Journal - Research Article

Aitchison, A., Hakkaart, C., Whitehead, M., Khan, S., Siddique, S., Ahmed, R., Frizelle, F. A., & Keenan, J. I. (2020). CDH1 gene mutation in early-onset, colorectal signet-ring cell carcinoma. Pathology: Research & Practice, 216, 152912. doi: 10.1016/j.prp.2020.152912

Journal - Research Article

Heenan, P., Creemers, R. H., Sharma, S., Keenan, J., Bayer, S., Young, W., … Skidmore, P. M., … Roy, N., Gearry, R. B., & COMFORT Cohort Collaborators. (2020). Cohort profile: The Christchurch IBS cOhort to investigate Mechanisms FOr gut Relief and improved Transit (COMFORT). Inflammatory Intestinal Diseases, 5(3), 132-143. doi: 10.1159/000508160

Journal - Research Article

Ho, S. S. C., Keenan, J. I., & Day, A. S. (2020). Role of serological tests in the diagnosis of coeliac disease in children in New Zealand. Journal of Paediatrics & Child Health, 56, 1906-1911. doi: 10.1111/jpc.15076

Journal - Research Article

Ho, S. S. C., Ross, M., Keenan, J. I., & Day, A. S. (2020). Fecal calprotectin in combination with standard blood tests in the diagnosis of inflammatory bowel disease in children. Frontiers in Pediatrics, 8, 609279. doi: 10.3389/fped.2020.609279

Journal - Research Article

Ho, S. S., Wall, C., Gearry, R. B., Keenan, J., & Day, A. S. (2020). A pilot study evaluating novel urinary biomarkers for Crohn's disease. Inflammatory Intestinal Diseases, 5(4), 212-220. doi: 10.1159/000510682

Journal - Research Article

Keenan, J., Aitchison, A., Leaman, J., Pearson, J., & Frizelle, F. (2019). Faecal biomarkers do not always identify pre-cancerous lesions in patients who present in primary care with bowel symptoms. New Zealand Medical Journal, 132(1501), 48-56. Retrieved from https://www.nzma.org.nz/journal

Journal - Research Article

Purcell, R. V., Kaakoush, N. O., Mitchell, H. M., Pearson, J. F., & Keenan, J. I. (2018). Gastrointestinal pathobionts in pediatric Crohn's disease patients. International Journal of Microbiology, 2018, 9203908. doi: 10.1155/2018/9203908

Journal - Research Article

Budd, G. R., Aitchison, A., Day, A. S., & Keenan, J. I. (2017). The effect of polymeric formula on enterocyte differentiation. Innate Immunity, 23(3), 240-248. doi: 10.1177/1753425916689333

Journal - Research Article

Chae, A., Aitchison, A., Day, A. S., & Keenan, J. I. (2017). Bovine colostrum demonstrates anti-inflammatory and antibacterial activity in in vitro models of intestinal inflammation and infection. Journal of Functional Foods, 28, 293-298. doi: 10.1016/j.jff.2016.11.016

Journal - Research Article

Flores, S. E., Aitchison, A., Day, A. S., & Keenan, J. I. (2017). Helicobacter pylori infection perturbs iron homeostasis in gastric epithelial cells. PLoS ONE, 12(9), e0184026. doi: 10.1371/journal.pone.0184026

Journal - Research Article

Purcell, R. V., Pearson, J., Aitchison, A., Dixon, L., Frizelle, F. A., & Keenan, J. I. (2017). Colonization with enterotoxigenic Bacteroides fragilis is associated with early-stage colorectal neoplasia. PLoS ONE, 12(2), e0171602. doi: 10.1371/journal.pone.0171602

Journal - Research Article

Aitchison, A., Frizelle, F. A., & Keenan, J. I. (2016). PCR detection of the Bacteroides fragilis enterotoxin gene relies on robust primer design. Journal of Clinical Microbiology, 54(1), 239-240. doi: 10.1128/jcm.02785-15

Journal - Research Article

Keenan, J. I., Aitchison, A., Purcell, R. V., Greenlees, R., Pearson, J. F., & Frizelle, F. A. (2016). Screening for enterotoxigenic Bacteroides fragilis in stool samples. Anaerobe, 40, 50-53. doi: 10.1016/j.anaerobe.2016.05.004

Journal - Research Article

Purcell, R. V., Pearson, J., Frizelle, F. A., & Keenan, J. I. (2016). Comparison of standard, quantitative and digital PCR in the detection of enterotoxigenic Bacteroides fragilis. Scientific Reports, 6, 34554. doi: 10.1038/srep34554

Journal - Research Article

Wakeman, C., Keenan, J., Eteuati, J., Hollington, P., Eglinton, T., & Frizelle, F. (2016). Chemoprevention of colorectal neoplasia. ANZ Journal of Surgery, 87(12), E228-E232. doi: 10.1111/ans.13392

Journal - Research Article

Wright, E. K., Kamm, M. A., De Cruz, P., Hamilton, A. L., Ritchie, K. J., Keenan, J. I., … Burgess, L., Aitchison, A., … Day, A. S., & Gearry, R. B. (2016). Comparison of fecal inflammatory markers in Crohn's disease. Inflammatory Bowel Diseases, 22(5), 1086-1094. doi: 10.1097/mib.0000000000000671

Journal - Research Article

Flores, S. E., Day, A. S., & Keenan, J. I. (2015). Measurement of total iron in Helicobacter pylori-infected gastric epithelial cells. Biometals, 28, 143-150. doi: 10.1007/s10534-014-9810-z

Journal - Research Article

Keenan, J. I., Hooper, E. M., Tyrer, P. C., & Day, A. S. (2014). Influences of enteral nutrition upon CEACAM6 expression by intestinal epithelial cells. Innate Immunity, 20(8), 848-856. doi: 10.1177/1753425913513309

Journal - Research Article

Meijer, B., Hoskin, T., Ashcroft, A., Burgess, L., Keenan, J. I., Falvey, J., Gearry, R. B., & Day, A. S. (2014). Total soluble and endogenous secretory receptor for advanced glycation endproducts (RAGE) in IBD. Journal of Crohn's & Colitis, 8(6), 513-520. doi: 10.1016/j.crohns.2013.11.004

Journal - Research Article

Tyrer, P. C., Frizelle, F. A., & Keenan, J. I. (2014). Escherichia coli-derived outer membrane vesicles are genotoxic to human enterocyte-like cells. Infectious Agents & Cancer, 9, 2. doi: 10.1186/1750-9378-9-2

Journal - Research Article

Keenan, J. I., Salm, N., Pearson, J. F., Gearry, R. B., & Day, A. S. (2013). Campylobacter seroreactivity in adults with recent onset of Crohn’s disease. Journal of Gastroenterology & Hepatology Research, 2(3), 468-472. doi: 10.6051/j.issn.2224-3992.2013.02.228

Journal - Research Article

Bentley, R. W., Keown, D. A., Gearry, R. B., Cameron, V. A., Keenan, J., Roberts, R. L., & Day, A. S. (2012). Vitamin D receptor polymorphisms in colorectal cancer in New Zealand: An association study. New Zealand Medical Journal, 125(1356). Retrieved from http://www.nzma.org.nz/journal

Journal - Research Article

Coray, D. S., Heinemann, J. A., Tyrer, P. C., & Keenan, J. I. (2012). Human lactoferrin increases Helicobacter pylori internalisation into AGS cells. World Journal of Microbiology & Biotechnology, 28(5), 1871-1880. doi: 10.1007/s11274-011-0984-z

Journal - Research Article

Keenan, J. I., Salm, N., Wallace, A. J., & Hampton, M. B. (2012). Using food to reduce H. pylori-associated inflammation. Phytotherapy Research, 26(11), 1620-1625. doi: 10.1002/ptr.4618

Journal - Research Article

Keown, D. A., Collings, D. A., & Keenan, J. I. (2012). Uptake and persistence of Mycobacterium avium subsp. paratuberculosis in human monocytes. Infection & Immunity, 80(11), 3768-3775. doi: 10.1128/iai.00534-12

Journal - Research Article

Parker, H., & Keenan, J. I. (2012). Composition and function of Helicobacter pylori outer membrane vesicles. Microbes & Infection, 14(1), 9-16. doi: 10.1016/j.micinf.2011.08.007

Journal - Research Article

Day, A. S., & Keenan, J. (2011). Probiotic-mediated modulation of host inflammation. Expert Review of Gastroenterology & Hepatology, 5(3), 319-321. doi: 10.1586/egh.11.34

Journal - Research Article

Glubb, D. M., Gearry, R. B., Barclay, M. L., Roberts, R. L., Pearson, J., Keenan, J. I., McKenzie, J., & Bentley, R. W. (2011). NOD2 and ATG16L1 polymorphisms affect monocyte responses in Crohn's disease. World Journal of Gastroenterology, 17(23), 2829-2837. doi: 10.3748/wjg.v17.i23.2829

Journal - Research Article

Keenan, J. I., Beaugie, C. R., Jasmann, B., Potter, H. C., Collett, J. A., & Frizelle, F. A. (2010). Helicobacter species in the human colon. Colorectal Disease, 12(1), 48-53. doi: 10.1111/j.1463-1318.2008.01672.x

Journal - Research Article

Keenan, J. I., Salm, N., Hampton, M. B., & Wallace, A. J. (2010). Individual and combined effects of foods on Helicobacter pylori growth. Phytotherapy Research, 24(8), 1229-1233. doi: 10.1002/ptr.3167

Journal - Research Article

Parker, H., Chitcholtan, K., Hampton, M. B., & Keenan, J. I. (2010). Uptake of Helicobacter pylori outer membrane vesicles by gastric epithelial cells. Infection & Immunity, 78(12), 5054-5061. doi: 10.1128/IAI.00299-10

Journal - Research Article

Munday, J. S., Keenan, J. I., Beaugie, C. R., & Sugiarto, H. (2009). Ovine small intestinal adenocarcinomas are not associated with infection by herpesviruses, Helicobacter species or Mycobacterium avium subspecies paratuberculosis. Journal of Comparative Pathology, 140(2-3), 177-181. doi: 10.1016/j.jcpa.2008.11.005

Journal - Research Article

Bentley, R. W., Keenan, J. I., Gearry, R. B., Kennedy, M. A., Barclay, M. L., & Roberts, R. L. (2008). Incidence of Mycobacterium avium subspecies paratuberculosis in a population-based cohort of patients with Crohn's disease and control subjects. American Journal of Gastroenterology, 103(5), 1168-1172. doi: 10.1111/j.1572-0241.2007.01742.x

Journal - Research Article

Chitcholtan, K., Hampton, M. B., & Keenan, J. I. (2008). Outer membrane vesicles enhance the carcinogenic potential of Helicobacter pylori. Carcinogenesis, 29(12), 2400-2405. doi: 10.1093/carcin/bgn218

Journal - Research Article

Keenan, J. I., Davis, K. A., Beaugie, C. R., McGovern, J. J., & Moran, A. P. (2008). Alterations in Helicobacter pylori outer membrane and outer membrane vesicle-associated lipopolysaccharides under iron-limiting growth conditions. Innate Immunity, 14(5), 279-290. doi: 10.1177/1753425908096857

Journal - Research Article

Piuhola, J., Kerkelä, R., Keenan, J. I., Hampton, M. B., Richards, A. M., & Pemberton, C. J. (2008). Direct cardiac actions of erythropoietin (EPO): Effects on cardiac contractility, BNP secretion and ischaemia/reperfusion injury. Clinical Science, 114(4), 293-304. doi: 10.1042/CS20070229

Journal - Research Article

Mandhan, P., Qi, B. Q., Keenan, J. I., Ismail, S., Beasley, S. W., & Sullivan, M. J. (2006). Counterstaining improves visualization of the myenteric plexus in immunolabelled whole-mount preparations. Journal of Fluorescence, 16, 655-658.

Journal - Research Article

Hynes, S. O., Keenan, J. I., Ferris, J. A., Annuk, H., & Moran, A. P. (2005). Lewis epitopes on outer membrane vesicles of relevance to Helicobacter pylori pathogenesis. Helicobacter, 10(2), 146-156.

Journal - Research Article

Keenan, J. I., Peterson, II, R. A., & Hampton, M. B. (2005). NADPH oxidase involvement in the pathology of Helicobacter pylori infection. Free Radical Biology & Medicine, 38, 1188-1196.

Journal - Research Article

Arsic, D., Cameron, V., Ellmers, L., Quan, Q. B., Keenan, J., & Beasley, S. (2004). Adriamycin disruption of the Shh-Gli pathway is associated with abnormalities of foregut development. Journal of Pediatric Surgery, 39(12), 1747-1753.

Journal - Research Article

Bland, M. V., Ismail, S., Heinemann, J. A., & Keenan, J. I. (2004). The action of bismuth against Helicobacter pylori mimics but is not caused by intracellular iron deprivation. Antimicrobial Agents & Chemotherapy, 48(6), 1983-1988.

Journal - Research Article

Keenan, J. I., Peterson, R. A., Fraser, R., Frampton, C. M., Walmsley, T. A., Allardyce, R. A., & Roake, J. A. (2004). The effect of Helicobacter pylori infection and dietary iron deficiency on host iron homeostasis: A study in mice. Helicobacter, 9(6), 643-650.

Journal - Research Article

Arsic, D., Keenan, J. I., Quan, Q., & Beasley, S. W. (2003). Differences in the levels of Sonic hedgehog protein during early foregut development caused by exposure to Adriamycin give clues to the role of the Shh gene in oesophageal atresia. Pediatric Surgery International, 19, 463-466.

Journal - Research Article

Ismail, S., Hampton, M. B., & Keenan, J. I. (2003). Helicobacter pylori outer membrane vesicles modulate proliferation and interleukin-8 production by gastric epithelial cells. Infection & Immunity, 71(10), 5670-5675.

Journal - Research Article

Keenan, J. I., Rijpkema, S., Durrani, Z., & Roake, J. A. (2003). Differences in immunogenicity and protection in mice and guinea pigs following intranasal immunization with Helicoba pylori outer membrane antigens. FEMS Immunology & Medical Microbiology, 36(3), 199-205.

Journal - Research Article

Hampton, M. B., Vissers, M. C., Keenan, J. I., & Winterbourn, C. C. (2002). Oxidant-mediated phosphatidylserine exposure and macrophage uptake of activated neutrophils: possible impairment in chronic granulomatous disease. Journal of Leukocyte Biology, 71(5), 775-781.

Journal - Research Article

Keenan, J. I., Neal, S., Allardyce, R. A., & Roake, J. A. (2002). Serum-derived IgG1-mediated immune exclusion as a mechanism of protection against H.pylori infection. Vaccine, 20, 2981-2988.

Journal - Research Article

Keenan, J. I., & Allardyce, R. A. (2000). Iron influences the expression of Helicobacter pylori outer membrane vesicle-associated virulence factors. European Journal of Gastroenterology & Hepatology, 12, 1-7.

Journal - Research Article

Keenan, J. I., Day, T., Neal, S., Cook, B., Perez-Perez, G., Allardyce, R. A., & Bagshaw, P. F. (2000). A role for the bacterial outer membrane in the pathogenesis of Helicobacter pylori infection. FEMS Microbiology Letters, 182, 259-264.

Journal - Research Article

Keenan, J., Oliaro, J., Domigan, N., Potter, H., Aitken, G., Allardyce, R., & Roake, J. (2000). Immune response to an 18-kilodalton outer membrane antigen identifies lipoprotein 20 as a Helicobacter pylori vaccine candidate. Infection & Immunity, 68(6), 3337-3343. doi: 10.1128/IAI.68.6.3337-3343.2000

Journal - Research Article

Keenan, J. I., Allardyce, R. A., & Bagshaw, P. F. (1998). Lack of protection following immunisation with H-pylori outer membrane vesicles highlights antigenic differences between H-felis and H-pylori. FEMS Microbiology Letters, 161(1), 21-27.

Journal - Research Article

Allardyce, R. A., Chapman, B. A., Tie, A. B., Burt, M. J., Yeo, K. J., Keenan, J. I., & Bagshaw, P. F. (1997). 37 kBq ¹⁴C-urea breath test and gastric biopsy analysis of H. pylori infection. Australian & New Zealand Journal of Surgery, 67(1), 31-34. doi: 10.1111/j.1445-2197.1997.tb01890.x

Journal - Research Article

Keenan, J. I., Allardyce, R. A., & Bagshaw, P. F. (1997). Dual silver staining to characterise helicobacter spp. outer membrane components. Journal of Immunological Methods, 209(1), 17-24.

Journal - Research Article

Allardyce, R. A., Bagshaw, P. F., & Keenan, J. I. (1995). The outcome of Helicobacter pylori infection. British Journal of Hospital Medicine, 54, 372-377.

Journal - Research Article

Ho, S. S. C., Keenan, J. I., & Day, A. S. (2022). Urinary chitinase 3-like 1 and intestinal fatty-acid binding proteins are not elevated in children with inflammatory bowel disease. Intestinal Research. Advance online publication. doi: 10.5217/ir.2022.00064

Journal - Research Other

Keenan, J. I., & Frizelle, F. A. (2022). Biomarkers to detect early-stage colorectal cancer. Biomedicines, 10(2), 255. doi: 10.3390/biomedicines10020255

Journal - Research Other

Permain, J., Appleton, L., Ho, S. S. C., Coffey, M., Ooi, C. Y., Keenan, J. I., & Day, A. S. (2022). Children with cystic fibrosis have elevated levels of fecal chitinase-3-like-1 [Short communication]. Journal of Pediatric Gastroenterology & Nutrition. Advance online publication. doi: 10.1097/mpg.0000000000003477

Journal - Research Other

Day, A. S., Keenan, J. I., & Tannock, G. W. (2020). The intestinal microbiota in health and disease. Journal of the Royal Society of New Zealand, 50(3), 367-370. doi: 10.1080/03036758.2020.1760896

Journal - Research Other

Heenan, P. E., Keenan, J. I., Bayer, S., Simon, M., & Gearry, R. B. (2020). Irritable bowel syndrome and the gut microbiota. Journal of the Royal Society of New Zealand, 50(3), 470-490. doi: 10.1080/03036758.2019.1695635

Journal - Research Other

Ho, S. S. C., Keenan, J. I., & Day, A. S. (2020). The role of gastrointestinal-related fatty acid-binding proteins as biomarkers in gastrointestinal diseases. Digestive Diseases & Sciences, 65, 376-390. doi: 10.1007/s10620-019-05841-x

Journal - Research Other

Keenan, J. I., & Frizelle, F. A. (2020). Toxigenic gut bacteria, diet and colon carcinogenesis. Journal of the Royal Society of New Zealand, 50(3), 418-433. doi: 10.1080/03036758.2019.1695636

Journal - Research Other

Keenan, J. I., Aitchison, A., Pearson, J. F., Frizelle, F. A., & Munday, J. S. (2019). Detection of the Bacteroides fragilis toxin gene in sheep with and without small intestinal adenocarcinoma [Short communication]. New Zealand Veterinary Journal, 67(6), 329-332. doi: 10.1080/00480169.2019.1651233

Journal - Research Other

Hock, B. D., McKenzie, J. L., & Keenan, J. I. (2017). Helicobacter pylori outer membrane vesicles inhibit human T cell responses via induction of monocyte COX-2 expression [Short communication]. Pathogens & Disease, 75(4), ftx034. doi: 10.1093/femspd/ftx034

Journal - Research Other

Keenan, J., Aitchison, A., & Frizelle, F. (2017). Are young people eating their way to bowel cancer? New Zealand Medical Journal, 130(1460), 90-92. Retrieved from https://www.nzma.org.nz/journal

Journal - Research Other

Keenan, J. I., & Frizelle, F. A. (2014). Bacteria flying under the radar: Linking a bacterial infection to colon carcinogenesis. Infectious Agents & Cancer, 9, 31. doi: 10.1186/1750-9378-9-31

Journal - Research Other

Keenan, J. I., Leaman, J. D., Greenlees, R., & Day, A. S. (2014). Is Campylobacter consisus an unrecognised cause of diarrhoea in New Zealand? New Zealand Medical Journal, 127(1391). Retrieved from http://www.nzma.org.nz/journal

Journal - Research Other

Keenan, J. I., & Day, A. S. (2013). Risks for celiac disease: Bacteria make it three. Digestive Diseases & Sciences, 58(11), 3066-3067. doi: 10.1007/s10620-013-2839-y

Journal - Research Other

Keenan, J. I., Mitchell, H. M., & Day, A. S. (2011). Interactions between gastric and enteric infections: Clues to the pathogenesis of inflammatory bowel disease? [Viewpoint]. New Zealand Medical Journal, 124(1332). Retrieved from http://journal.nzma.org.nz/journal/124-1332/4606/content.pdf

Journal - Research Other

Gearry, R. B., Aitken, J. M., Roberts, R. L., Ismail, S. L., Keenan, J., & Barclay, M. L. (2005). Gastrointestinal: Mycobacterium avium paratuberculosis and Crohn's disease. Journal of Gastroenterology & Hepatology, 20(12), 1943. doi: 10.1111/j.1440-1746.2005.04187.x

Journal - Research Other