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Welcome to the gastrointestinal surgery laboratory web page. Our lab is
engaged in several areas of research all relating to gastrointestinal
1) We are currently studying the mechanism of stress-induced GI motility disorders. Restraint stress delays solid gastric emptying, while it accelerates colonic transit in conscious rats. Our recent study indicates that the inhibitory effect of restraint stress on solid gastric emptying is mediated via central corticotropin releasing factor (CRF) and peripheral sympathetic neurons. In contrast, the stimulatory effect of restraint stress on colonic transit is mediated via central CRF and peripheral parasympathetic neurons. We will further study the interaction between central CRF and peripheral autonomic nervous system.
2) Although acupuncture
has been used to treat gastrointestinal (GI) symptoms in China for more than
3,000 years, mechanism of the beneficial effects of acupuncture remains
mysterious. We are currently studying the mechanism and effect of
acupuncture on gut motility using conscious dogs and rats. We have
previously showed that acupuncture on the abdomen causes a relaxation of the
stomach, while acupuncture on the lower leg causes a contraction in rats.
Acupuncture-induced gastric relaxation is mediated via somato-sympathetic
contractile effect of acupuncture on the hind limb is mediated via
In conscious dogs, acupuncture at the wrist prevents emesis induced by
vasopressin. The anti-emetic effect of acupuncture is mediated via a
central opioid pathway. This information will be conveyed to the clinic and
the beneficial effects acupuncture will be tested in patients with
functional GI disorders.
Several of our recent projects have also focused on the mechanisms of
intestinal inflammation. These studies examined the role sensory neurons and
their receptors in the initiation of inflammation. Recently, we have
investigated a novel sodium channel receptor, the vanilloid receptor –1
(VR-1) on acute and chronic models of colitis and esophagitis. By
pharmacologically blocking VR-1 and using VR-1 knock-out mice we have found
a significant attenuation in the inflammation in these models. Further
research will examine potential endogenous ligands for VR-1 and also examine
more chronic inflammatory models.
We have participated in several pre-clinical trials and clinical trials of
bio-scaffolding agents and bio-sealants. We have examined the usefulness of
a porcine submucosal matrix (Surgisis) as a biodegradable graft for
gastrointestinal healing and have also initiated a trial of a bio-sealants
in an intestinal anastomotic failure model.
We continue to investigate clinical projects that relate to gastrointestinal
surgical diseases. Numerous projects have been and a currently being
investigated such as the use of neo-adjuvant therapy for rectal cancer,
measurements of quality for colorectal cancer, and a NSQIP analysis of
vagotomy and drainage versus vagotomy and resection procedures for bleeding
peptic ulcer disease.