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Dr Sahar Mohammed


GI Physiologist Lower Gastrointestinal Physiology Unit Clinical Manager


Sahar D Mohammed is Clinical Manager for the Lower gastrointestinal (GI) Physiology Unit. The Unit provides a joint Service between Queen Mary University of London and Barts Health NHS Trust. She spends her time on managing day-to-day clinical GI Physiology Service, undertaking lower GI Physiology testing, improving the delivery of the Service, and supporting on going clinical research. She is also supervising the clinical training for performing Lower GI Physiology within the Unit. She qualified from the University of Al-Mustansiria/ Baghdad in 2004 (MBChB) and undertook a MSc and a PhD in gastroenterology at Queen Mary University of London. She also holds a University Certificate in GI Physiology from De Montfort University.



Research Interests:

Her main clinical interests are in the underlying pathophysiology and current / novel diagnostic tools of:

  1. Functional colorectal disorders e.g. chronic constipation;
  2. Pelvic floor disorders including prolapse and faecal incontinence;
  3. Anorectal disorders following traumatic vaginal birth

Her main research interests are:

  1. Pathophysiology of colonic motility disorders focusing on chronic constipation;
  2. Evaluation of new technologies for investigating colonic motility disorders, specifically chronic constipation


  1. Dinning PG, Zarate N, Szczesniak MM, Mohammed SD, Preston SL, Fairclough PD, Lunniss PJ, Cook IJ, Scott SM. Bowel preparation affects the amplitude and spatiotemporal organization of colonic propagating sequences.  Neurogastroenterol Motil 2010, 22(6): 633 -e176.
  2. Dinning PG, Zarate N, Hunt LM, Fuentealba SE, Mohammed SD, Szczesniak MM, Lubowski DZ, Preston SL, Fairclough PD, Lunniss PJ, Scott SM, Cook IJ. Pancolonic spatiotemporal mapping reveals regional deficiencies in, and disorganization of colonic propagating pressure waves in severe constipation. Neurogastroenterol Motil. 2010; 22 (12): e340 - 9.
  3. Zarate N, Farmer AD, Grahame R, Mohammed SD, Knowles CH, Scott SM, Aziz Q. Unexplained gastrointestinal symptoms and joint hypermobility: is connective tissue the missing link?. Neurogastroenterol Motil. 2010; 22 (3): 252 - e78.
  4. Mohammed SD, Lunniss PJ, Zarate N, Farmer AD, Grahame R, Aziz Q, Scott SM. Joint hypermobility and rectal evacuatory dysfunction: an etiological link in abnormal connective tissue?. Neurogastroenterol Motil. 2010; 22 (10): 1085 - e283.
  5. Zarate N, Mohammed SD, O'Shaughnessy E, Newell M, Yazaki E, Williams NS, Lunniss PJ, Semler JR, Scott SM. Accurate localization of a fall in pH within the ileocecal region: validation using a dual-scintigraphic technique. Am J Physiol Gastrointest Liver Physiol. 2010; 299 (6): 1276 - 86.
  6. Wiklendt L, Mohammed SD, Scott SM, Dinning PG. Classification of normal and abnormal colonic motility based on cross-correlations of pancolonic manometry data. Neurogastroenterol Motil. 2013; 25 (3): e215 - 23.
  7. Farmer AD, Mohammed SD, Dukes GE, Scott SM, Hobson AR. Caecal pH is a biomarker of excessive colonic fermentation. World J Gastroenterol. 2014; 20 (17): 5000 - 7.
  8. Wang YT, Mohammed SD, Farmer AD, Wang D, Zarate N, Hobson AR, Hellström PM, Semler JR, Kuo B, Rao SS, Hasler WL, Camilleri M, Scott SM. Regional gastrointestinal transit and pH studied in 215 healthy volunteers using the wireless motility capsule: influence of age, gender, study country and testing protocol. Aliment Pharmacol Ther. 2015; 42 (6): 761 - 72.
  9. Farmer AD, Pedersen AG, Brock B, Jakobsen PE, Karmisholt J, Mohammed SD, Scott SM, Drewes AM, Brock C.Type 1 diabetic patients with peripheral neuropathy have pan-enteric prolongation of gastrointestinal transit times and an altered caecal pH profile. 2017; 60 (4): 709 - 718.
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