Associate Professor Jacqui Keenan

2026

Journal - Research Article

Carco, C., Young, W., Mullaney, J., Heenan, P. E., Gearry, R. B., Forbes-Blom, E., Keenan, J. I., … Roy, N. C. (2026). Taxonomical and functional characterisation of the faecal microbiota and symptom integrative analysis in subjects with disorders of gut-brain interactions. Heliyon, 12, e44952. doi: 10.1016/j.heliyon.2026.e44952

Dowrick, J. M., Roy, N. C., Carco, C., James, S. C., Heenan, P. E., Frampton, C. M. A., … Keenan, J. I., … Bayer, S. B., … Gearry, R. B., & Angeli-Gordon, T. R. (2026). Integrated multi-omic and symptom clustering reveals lower-gastrointestinal disorders of gut-brain interaction heterogeneity. Gut Microbes, 18(1), 2604871. doi: 10.1080/19490976.2025.2604871

Journal - Research Other

Dawson, K. L., Waddell, O., Frizelle, F., & Keenan, J. I. (2026). Dietary sugar intake as a risk factor for early-onset colorectal cancer in young New Zealanders. New Zealand Medical Journal/Te ara tika o te hauora hapori, 139(1633), 100-103. doi: 10.26635/6965.e1633

2025

Journal - Research Article

Waddell, O., McCombie, A., Glyn, T., Pearson, J., Keenan, J., & Frizelle, F. (2025). The pathway to diagnosis of early-onset colorectal cancer: Exploring diagnostic intervals and their effect on outcomes. Future Oncology. Advance online publication. doi: 10.1080/14796694.2025.2526319

Conference Contribution - Published proceedings: Abstract

Waddell, O., McCombie, A., Keenan, J., Frizelle, F., Glyn, T., & Pearson, J. (2025). Early-onset colorectal cancer: Diagnostic pathways and their impact on outcomes. ANZ Journal of Surgery, 95(Suppl. 1), CR071P. doi: 10.1111/ans.70063

Waddell, O., McCombie, A., Keenan, J., Pearson, J., Glyn, T., & Frizelle, F. (2025). A prospective cohort study of quality of life in early-onset colorectal cancer. ANZ Journal of Surgery, 95(Suppl. 1), CR029P. doi: 10.1111/ans.70063

2024

Journal - Research Article

Fraser, K., James, S. C., Young, W., Gearry, R. B., Heenan, P. E., Keenan, J. I., … Roy, N. C. (2024). Characterisation of the plasma and faecal metabolomes in participants with functional gastrointestinal disorders. International Journal of Molecular Sciences, 25, 13465. doi: 10.3390/ijms252413465

Waddell, O., Pearson, J., McCombie, A., Marshall, H., Purcell, R., Keenan, J., Glyn, T., & Frizelle, F. (2024). The incidence of early onset colorectal cancer in Aotearoa New Zealand: 2000–2020. BMC Cancer, 24, 456. doi: 10.1186/s12885-024-12122-y

Vernon-Roberts, A., Premaratne, M., Wright, R., Keenan, J. I., & Day, A. S. (2024). Profile of Helicobacter pylori infections among children in the South Island of New Zealand (2010-2021). Helicobacter, 29, e13037. doi: 10.1111/hel.13037

Journal - Research Other

Waddell, O., Keenan, J., & Frizelle, F. (2024). Challenges around diagnosis of early onset colorectal cancer, and the case for screening. ANZ Journal of Surgery, 94, 1687-1692. doi: 10.1111/ans.19221

Conference Contribution - Published proceedings: Abstract

Dawson, K., Day, A., & Keenan, J. I. (2024). Colonic mucus attenuates the genotoxic effect of the Bacteroides fragilis toxin. Journal of Gastroenterology & Hepatology, 39(Suppl. 1), (pp. 264). doi: 10.1111/jgh.16703

Waddell, O., Keenan, J., & Frizelle, F. (2024). Early onset colorectal cancer and screening. ANZ Journal of Surgery, 94(Suppl. 1), GS036P. 80. doi: 10.1111/ans.18951

Waddell, O., Pearson, J., McCombie, A., Marshall, H., Glyn, T., Purcell, R., Keenan, J., & Frizelle, F. (2024). The rising incidence of early onset colorectal cancer in Aotearoa New Zealand: Changing trends from 2000 to 2020. ANZ Journal of Surgery, 94(Suppl. 1), GS003. doi: 10.1111/ans.18951

Conference Contribution - Verbal presentation and other Conference outputs

Keenan, J. (2024, October). Other colorectal cancer risk factors in Canterbury. Verbal presentation at the New Zealand Institute of Agricultural & Horticultural Science Canterbury Forum: Nitrogen: Friend or Foe? Lincoln, New Zealand.

2023

Journal - Research Article

Waddell, O., Frizelle, F. A., & Keenan, J. I. (2023). The role of biomarkers to increase the detection of early-onset colorectal cancer. Medical Research Archives, 11(11). doi: 10.18103/mra.v11i11.4690

Keenan, J. I., Aitchison, A., Frizelle, F. A., & Hock, B. D. (2023). Detection of chitinase 3-like 1 in symptomatic primary care patient faecal samples is not a reliable biomarker of colonic lesions. Asian Pacific Journal of Cancer Prevention, 24(7), 2289-2293. doi: 10.31557/APJCP.2023.24.7.2289

Ali, H., Douwes, J., Burmanje, J., Gokhale, P., Crane, J., Pattemore, P., Stanley, T., Keenan, J., & Brooks, C. (2023). Sputum inflammatory, neural, and remodeling mediators in eosinophilic and noneosinophilic asthma. Annals of Allergy, Asthma & Immunology, 130, 776-783. doi: 10.1016/j.anai.2023.03.015

Thompson, N., Gatenby, G., Waddell, O., Purcell, R., Keenan, J., Pearson, J. F., Frizelle, F., & Glyn, T. (2023). Early onset colorectal cancer in Canterbury, New Zealand. ANZ Journal of Surgery, 93, 2148-2154. doi: 10.1111/ans.18357

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

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 Other

Li, S., Keenan, J. I., Shaw, I. C., & Frizelle, F. A. (2023). Could microplastics be a driver for early onset colorectal cancer? Cancers, 15, 3323. doi: 10.3390/cancers15133323

Conference Contribution - Verbal presentation and other Conference outputs

Pearson, J., Waddell, O., McCombie, A., Marshall, H., Purcell, R., Keenan, J., Glyn, T., & Frizelle, F. (2023, November-December). The incidence of early-onset colorectal cancer in Aotearoa: 2000-2020. Verbal presentation at the International Biometric Society Australasian Region (IBS-AR) and the Statistical Ecology and Environmental Monitoring (SEEM) Joint Conference, Waitangi, New Zealand.

2022

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

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

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 Other

Waddell, O., Keenan, J., & Frizelle, F. (2022). Early-onset colorectal cancer: Never too young. New Zealand Medical Journal, 135(1563), 7-11. Retrieved from https://journal.nzma.org.nz/

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, 20(4), 509-513. doi: 10.5217/ir.2022.00064

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. Journal of Pediatric Gastroenterology & Nutrition, 75(1), 48-51. doi: 10.1097/mpg.0000000000003477

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

Conference Contribution - Published proceedings: Abstract

Thompson, N., Gatenby, G., Waddell, O., Keenan, J., Frizelle, F., & Glyn, T. (2022). Characteristics of early-onset colorectal cancer in the Canterbury population. ANZ Journal of Surgery, 92(Suppl. 1), (pp. 34). doi: 10.1111/ans.17609

2021

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.

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

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

Conference Contribution - Published proceedings: Abstract

Ho, S. S., Keenan, J., & Day, A. (2021). Chitinase-3-like protein 1 levels in feces but not urine as an emerging biomarker of pediatric inflammatory bowel disease. Journal of Gastroenterology & Hepatology, 36(Suppl. 3), (pp. 164). doi: 10.1111/jgh.15617

2020

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

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

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

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

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

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 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

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

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

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

Conference Contribution - Published proceedings: Abstract

Heenan, P., Frampton, C., Young, W., Roy, N., Keenan, J., Wall, C., … Gearry, R. (2020). Gastrointestinal and mental health symptoms group participants in an irritable bowel syndrome cohort. Journal of Gastroenterology & Hepatology, 35, (pp. 173). doi: 10.1111/jgh.15273

Ho, S. S., Keenan, J., & Day, A. (2020). Patient perceptions of current and potential inflammatory bowel disease diagnostic and monitoring tests. Journal of Gastroenterology & Hepatology, 35(Suppl. 1), (pp. 109-110). doi: 10.1111/jgh.15271

Roy, N., Heenan, P., Wall, C., Young, W., Carco, C., Keenan, J., … Gearry, R. (2020). Association of habitual dietary fiber intake and fecal microbiome gene abundance with gastrointestinal symptoms in an irritable bowel syndrome cohort. Current Developments in Nutrition, 4(Suppl. 2), (pp. 1581). doi: 10.1093/cdn/nzaa062_038

2019

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 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. New Zealand Veterinary Journal, 67(6), 329-332. doi: 10.1080/00480169.2019.1651233

Conference Contribution - Published proceedings: Abstract

Ho, S., Ross, M., Keenan, J., & Day, A. (2019). The role of fecal calprotectin in the diagnosis of inflammatory bowel disease in children. Journal of Gastroenterology & Hepatology, 34(Suppl. 2), (pp. 206). doi: 10.1111/jgh.14795

Ho, S., Keenan, J., & Day, A. (2019). The role of combination serological tests in the diagnosis of celiac disease in children. Journal of Gastroenterology & Hepatology, 34(Suppl. 2), (pp. 206). doi: 10.1111/jgh.14795

2018

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

Conference Contribution - Published proceedings: Abstract

Aitchison, A., Hakkaart, C., Kahn, S., Whitehead, M., Frizelle, F., & Keenan, J. (2018). E-cadherin in early-onset colorectal signet-ring cell carcinoma. Proceedings of the New Zealand Society for Oncology (NZSO) Conference. Retrieved from http://www.nzsoncology.org.nz/

Conference Contribution - Poster Presentation (not in published proceedings)

Swan, J., Aitchison, A., Hampton, M., & Keenan, J. (2018, September). Asprin's role in preventing e-cadherin cleavage by the carcinogenic Bacteroides Fragilis toxin. Poster session presented at the Otago Spotlight Symposium on Infectious Disease, Wellington, New Zealand.

2017

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

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

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

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 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

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

Conference Contribution - Published proceedings: Abstract

Sharma, S., Heenan, P., Keenan, J., Willington, A., & Gearry, R. (2017). The association between smoking and belly pain in participants from the Christchurch IBS cOhort to investigate Mechanisms FOr gut Relief and improved Transit (COMFORT). Proceedings of the New Zealand Society of Gastroenterology and the NZNO Gastroenterology Nurses' College Annual Scientific Meeting. 67. Retrieved from http://gastro2017.co.nz

Heenan, P., Sharma, S., Keenan, J., Willington, A., & Gearry, R. (2017). Anxiety and depression are associated with irritable bowel syndrome: Preliminary results from Christchurch IBS cOhort to investigate Mechanisms FOr gut Relief and improved Transit (COMFORT) study. Proceedings of the New Zealand Society of Gastroenterology and the NZNO Gastroenterology Nurses' College Annual Scientific Meeting. 22. Retrieved from http://gastro2017.co.nz

2016

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

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

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

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

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

Conference Contribution - Verbal presentation and other Conference outputs

Keenan, J. (2016, September). Bugs and bowel cancer. Verbal presentation at the Colorectal Surgical Society of Australia and New Zealand (CSSANZ) and the Colon & Rectal Surgery Section, Royal Australasian College of Surgeons (RACS) Spring Colorectal Meeting, Queenstown, New Zealand.

Purcell, R., Pearson, J., Keenan, J., Schmeier, S., & Frizelle, F. (2016, August-September). Bacterial dysbiosis and the development of colorectal cancer. Verbal presentation at the Queenstown Molecular Biology (QMB) Meetings, Nelson, New Zealand.

2015

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

Conference Contribution - Poster Presentation (not in published proceedings)

Hock, B. D., McKenzie, J. L., & Keenan, J. I. (2015, November). Helicobacter pylori outer membrane vesicles modulate human immune responses. Poster session presented at the 18th International Conference on Campylobacter, Helicobacter, and Related Organisms (CHRO), Rotorua, New Zealand.

2014

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

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

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 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

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

Conference Contribution - Published proceedings: Abstract

Keenan, J., Aitchison, A., Greenlees, R., & Frizelle, F. (2014). Are toxin-producing strains of Bacteroides fragilis involved in colorectal cancer? ANZ Journal of Surgery, 84(Suppl. 1), (pp. 36). doi: 10.1111/ans.12609

Wright, E. K., De Cruz, P., Kamm, M. A., Hamilton, A. L., Ritchie, K. J., Krejany, S., … Keenan, J. I., … Day, A. S., Gearry, R. B., & Desmond, P. V. (2014). Faecal calprotectin is superior to faecal lactoferrin and S100A12 as a surrogate marker for post-operative Crohn's disease endoscopic recurrence: Prospective longitudinal endoscopic validation: Results from the POCER Study. Gastroenterology, 146(5, Suppl. 1), (pp. S-174). doi: 10.1016/S0016-5085(14)60617-X

Conference Contribution - Poster Presentation (not in published proceedings)

Braun, J., Keenan, J., Schultz, M., & Butt, G. (2014, November). Polarization of Caco2 cells impedes uptake of outer membrane vesicles. Poster session presented at the New Zealand Society of Gastroenterology & New Zealand Nurses Organisation Gastroenterology Section Annual Scientific Meeting, Auckland, New Zealand.

Conference Contribution - Verbal presentation and other Conference outputs

Keenan, J., Aitchison, A., Greenlees, R., Pearson, J., & Frizelle, F. (2014, October). Are toxin-producing strains of Bacteroides fragilis involved in colorectal cancer? Verbal presentation at the New Zealand Society for Oncology (NZSO) Conference, Tauranga, New Zealand.

Keenan, J. (2014, August). The role of gut bacteria. Workshop presentation at the South General Practice Conference & Medical Exhibition (GP CME), Dunedin, New Zealand.

2013

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 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

Conference Contribution - Verbal presentation and other Conference outputs

Keenan, J. (2013, August). Gut bacteria and colorectal cancer. Verbal presentation at the National Rectal Cancer Summit, Wellington, New Zealand.

Keenan, J. (2013, February). Unravelling gastrointestinal disease. Verbal presentation at the Christchurch Medical School 40th Anniversary Celebrations, Christchurch, New Zealand.

2012

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

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

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

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

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 - Professional & Other Non-Research Articles

Keenan, J. (2012). Laboratory mice: Are you getting more than you paid for? ANZCCART News, 25(2), 5-6.

Conference Contribution - Published proceedings: Abstract

Falvey, J. D., Munday, J. S., Keenan, J. I., Dyer, A. E., Gearry, R. B., & Hampton, M. B. (2012). Clinical assessment of murine Dextran Sodium Sulphate (DSS) colitis: Prospective validation of a novel scoring tool. New Zealand Medical Journal, 125(1367). Retrieved from http://www.nzma.org.nz/journal

Conference Contribution - Poster Presentation (not in published proceedings)

Keown, D. A., Collings, D. A., & Keenan, J. I. (2012, June). Mycobacterium avium subspecies paratuberculosis impairs phagosome trafficking in human monocytes. Poster session presented at the American Society for Microbiolgoy (ASM) 112th General Meeting, San Francisco, USA.

Conference Contribution - Verbal presentation and other Conference outputs

Keenan, J. (2012, May). Gut bacteria: A cause of cancer? Verbal presentation at the New Zealand Society for Oncology (NZSO) Conference, Wellington, New Zealand.

2011

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

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 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

Conference Contribution - Published proceedings: Abstract

Braun, J. H., Butt, A. G., Keenan, J. I., & Schultz, M. (2011). Outer membrane vesicles (OMV) from intestinal bacteria as means of communication: Comparison of the effects of OMV from three different Escherichia coli strains on intestinal epithelial cells in vitro. New Zealand Medical Journal, 124(1347). Retrieved from http://journal.nzma.org.nz/journal/124-1347/5015/content.pdf

Falvey, J. D., Munday, J. S., Keenan, J. I., Gearry, R. B., & Hampton, M. B. (2011). Assessing the efficacy of isothiocyanates in experimental colitis. New Zealand Medical Journal, 124(1347). Retrieved from http://journal.nzma.org.nz/journal/124-1347/5015/content.pdf

2010

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

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

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

2009

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

2008

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

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

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

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

Conference Contribution - Published proceedings: Abstract

Chitcholtan, K., Hampton, M., & Keenan, J. (2008). Outer membrane vesicles (OMVs) of Helicobacter pylori alter cellular signalling pathways in human gastric epithelial cells. New Zealand Medical Journal, 121(1271). Retrieved from http://journal.nzma.org.nz/journal/121-1271/2990/content.pdf

Conference Contribution - Verbal presentation and other Conference outputs

Keenan, J., Stebbings, S., Bentley, R., Roberts, R., Lindstroem, A., Woods, P., Duncan, A., … and others. (2008, November). 2nd Workshop on Intestinal Permeability. Verbal presentation at the Satellite Symposium, Medical Sciences Congress, Queenstown, New Zealand.

Piuhola, J., Kerkelä, R., Keenan, J. I., Hampton, M. B., Richards, A. M., & Pemberton, C. (2008, November). Direct cardiac actions of erythropoietin (EPO): Effects on cardiac contractility, BNP secretion and ischemia-reperfusion injury. Verbal presentation at the Medical Sciences Congress, Queenstown, New Zealand.

Bentley, R., Glubb, D. M., Keenan, J. I., Gearry, R. B., Barclay, M. L., & Roberts, R. L. (2008, November). Mycobacterium Avium subsp. Paratuberculosis associated with Crohn's disease in New Zealand. Verbal presentation at the Medical Sciences Congress, Queenstown, New Zealand.

Keenan, J. (2008, November). Bacterial outer membrane vesicles. Verbal presentation at the Medical Sciences Congress, Queenstown, New Zealand.

2007

Conference Contribution - Published proceedings: Abstract

Bentley, R. W., Gearry, R. B., Keenan, J. I., Aitken, J. M., Kennedy, M. A., Barclay, M. L., & Roberts, R. L. (2007). Relative incidence of Mycobacterium avium subsp. paratuberculosis in a population-based cohort of Crohn's disease patients. Gut. 56(Suppl. III), (pp. A127). [Abstract]

Bentley, R. W., Gearry, R. B., Keenan, J. I., Aitken, J. M., Kennedy, M. A., Barclay, M. L., & Roberts, R. L. (2007). Relative incidence of Mycobacterium avium subsp. paratuberculosis in a population-based cohort of Crohn's disease patients. Journal of Gastroenterology and Hepatology. 22(Suppl. 3), (pp. A317). [Abstract]

Chitcholtan, K., Hampton, M., & Keenan, J. (2007). H. pylori outer membrane vesicles induce DNA damage in gastric epithelial cells. Zoonoses and Public Health. 54(Suppl. 1), (pp. 155). [Abstract]

Salm, N., Hampton, M., Wallace, A. J., & Keenan, J. (2007). Broccoli sprouts inhibit the release of interleukin-8 from AGS cells co-cultured with Helicobacter pylori. Zoonoses and Public Health. 54(Suppl. 1), (pp. 97-98). [Abstract]

Davis, K. A., Chitcholtan, K., Hampton, M., & Keenan, J. I. (2007). Helicobacter pylori outer membrane vesicles induce cytoskeletal rearrangements and cell signaling events in gastric epithelial cells. Zoonoses and Public Health. 54(Suppl. 1), (pp. 151). [Abstract]

Conference Contribution - Verbal presentation and other Conference outputs

Bentley, R. W., Roberts, R. L., Gearry, R. B., Keenan, J. I., Kennedy, M. A., & Barclay, M. L. (2007, November). Relative incidence of Mycobacterium avium subsp. paratuberculosis in a New Zealand population-based cohort of patients with Crohn's disease. Verbal presentation at the New Zealand Society of Gastroenterology & NZNO Gastroenterology Nurses Section Annual Scientific Meeting combined with the RACP and IMSANZ, Christchurch, New Zealand.

2006

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.

2005

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.

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 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

Conference Contribution - Published proceedings: Abstract

Ismail, S., Jasmann, B., Potter, H., & Keenan, J. (2005). Extragastric Helicobacter species in patients presenting for colonoscopy. In V. Korolik, A. Lee, H. Mitchell, G. Mendz, B. Fry & P. Coloe (Eds.), Proceedings of the 13th International Workshop on Campylobacter, Helicobacter and Related Organisms. (pp. 58). [Abstract]

Parker, H., Ismail, S., Neal, S., Hampton, M., & Keenan, J. (2005). Association of Helicobacter pylori outer membrane vesicles with gastric epithelial cells. In V. Korolik, A. Lee, H. Mitchell, G. Mendz, B. Fry & P. Coloe (Eds.), Proceedings of the 13th International Workshop on Campylobacter, Helicobacter and Related Organisms. (pp. 72). [Abstract]

Conference Contribution - Verbal presentation and other Conference outputs

Keenan, J., Peterson, R., Ismail, S., Hock, B., Frampton, C., & Hampton, M. (2005, September). Host iron deficiency alters the outcome of infection in Helicobacter pylori-infected mice. Verbal presentation at the 13th International Workshop on Campylobacter, Helicobacter and Related Organisms, Gold Coast, Australia.

2004

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.

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.

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.

Conference Contribution - Published proceedings: Abstract

Keenan, J. I., Peterson, R. A., & Hampton, M. B. (2004). Role of neutrophil oxidants in the gastric pathology associated with Helicobacter pylori infection. Helicobacter. 9(5), (pp. 591-592). [Abstract]

Keenan, J. I., Ismail, S., McGovern, J. J., & Moran, A. P. (2004). Iron availability influences lipopolysaccharide expression on Helicobacter pylori bacteria and outer membrane vesicles. Helicobacter. 9(5), (pp. 500). [Abstract]

Mandhan, P. L., Beasley, S. W., Quan, Q. B., Keenan, J., Ismail, S., & Sullivan, M. (2004). Counterstaining improves visualization of the myenteric plexus in immunolabelled whole-mount preparations. Australian & New Zealand Journal of Surgery, 74(Suppl.), (pp. A87-A88). [Abstract]

2003

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.

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.

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 - Professional & Other Non-Research Articles

Keenan, J., Neal, S., & Gearry, R. B. (2003). Non-pylori Helicobacter [Medical image]. New Zealand Medical Journal, 116(1179). Retrieved from http://journal.nzma.org.nz/journal/116-1179/546/content.pdf

Conference Contribution - Published proceedings: Abstract

Ismail, S., Parker, H., Hampton, M. B., & Keenan, J. I. (2003). Helicobacter pylori outer membrane vesicles modulate proliferation and IL-8 production by gastric epithelial cells. International Journal of Medical Microbiology, 293(Suppl. 35), (pp. 116). [Abstract]

Conference Contribution - Verbal presentation and other Conference outputs

Beasley, S. W., Arsic, D., Keenan, J. I., & Quan, Q. (2003, May). Disruption of Shh Gli signalling pathway associated with abnormal foregut development. Verbal presentation at the 36th Annual Meeting of the Pacific Association of Pediatri Surgeons with Australasian Association of Paediatric Surgeons, Australia.

2002

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.

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.

Conference Contribution - Published proceedings: Abstract

Arsic, D., Keenan, J. I., Beasley, S. W., & Qi, B.-Q. (2002). Expression of SHH protein in the rat foregut varies according to the embryological stage. Australian and New Zealand Journal of Surgery. 72(Suppl.), (pp. A76). [Abstract]

2001

Conference Contribution - Published proceedings: Abstract

Keenan, J. I., Fraser, R., Allardyce, R. A., & Roake, J. A. (2001). H. pylori infection, iron deficiency and disease expression in mice. International Journal of Medical Microbiology. 291(Suppl.31), (pp. 134). [Abstract]

Keenan, J. I., Rijpkema, S., Durrani, Z., & Roake, J. A. (2001). Differences in immunogenicity and protection in mice and guinea pigs following intra-nasal immunization with rLpp20. International Journal of Medical Microbiology. 291(Suppl.31), (pp. 156). [Abstract]

2000

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

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.

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.

Conference Contribution - Published proceedings: Abstract

Keenan, J. I., Hampton, M. B., & Allardyce, R. A. (2000). H. pylori proteases and the develpoment of gastric cancer. Gut. 47(Suppl. 1), (pp. A27). [Abstract]

Keenan, J. I., & Allardyce, R. A. (2000). IgG1-mediated immune exclusion of H. pylori in vivo. Gut. 47(Suppl. 1), (pp. A61). [Abstract]

1999

Conference Contribution - Published proceedings: Abstract

Keenan, J. I., & Allardyce, R. A. (1999). Iron levels during growth influence the expression of H. pylori virulence factors. 10th International Workshop on Campylobacter, Helicobacter & Related Organisms. HP36, (pp. 154). [Abstract]

1998

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.

1997

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

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.

Conference Contribution - Published proceedings: Abstract

Keenan, J. I., Allardyce, R. A., & Bagshaw, P. F. (1997). Identification of a novel H. pylori vaccine candidate. Gut. 41, (pp. 61). [Abstract]

Keenan, J. I., Allardyce, R. A., & Bagshaw, P. F. (1997). A role for the bacterial outer membrane in the pathogenesis of H. pylori infection. Gut. 41, (pp. 18). [Abstract]

1995

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.