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Biomedical subjects

D B Gibb

Publications and source records attributed to D B Gibb.

13 recordsLinked to original sources

Brian Dwyer and the St. Vincent's Pain Clinic 1962 to 1989.

Brian Dwyer was the Director of the Department of Anaesthetics at St. Vincent's Hospital in Sydney from 1955 to 1985. He developed a major interest in the management of intractable pain and was most impressed by the multidisciplinary pain clinic which was commissioned at the University of Washington in Seattle by John Bonica in 1960. In August 1962, Dr Dwyer established the first pain clinic in Australia, based on the Seattle model. Initially the St. Vincent's Pain Clinic specialized in the management of pain of malignant origin but in the 1970s and 1980s the work expanded to include the treatment of pain arising from a variety of benign conditions. The great strengths of the Pain Clinic were its multidisciplinary approach to pain problems and the realisation of the importance of psychological factors in the persistence of pain. As a result of his work, Brian Dwyer received international recognition as a pioneer in the field of chronic pain management and the St. Vincent's Pain Clinic served as a model for the establishment of similar units, both in Australia and overseas. Brian Dwyer was the first chairman of the Clinic and remained in that position until his retirement in 1989.

Anesthesiology↗

Neurogenic pathways mediating ascending and descending reflexes at the porcine ileocolonic junction.

We studied the pharmacology of the neural pathways mediating the responses of ileo- and coloileo-colonic junction (ICJ) to regional distension in ten anaesthetized pigs. Using manometric pullthroughs and a sleeve sensor, we found the ICJ demonstrated sustained tone that was resistant to tetrodotoxin. Ileal distension decreased ICJ pressure by 22.2 ¿ 10.1% (11.9 ¿ 2.7-10.1 ¿ 2.6 mmHg; P=0.002) and colonic distension augmented ICJ pressure by 23.5 ¿ 8.6% (12.8 ¿ 1.5-15.6 ¿ 2.1 mmHg; P=0.02). Bethanecol and Nw-nitro-L-arginine methyl ester (L-NAME) increased ICJ pressure (P=0.002, P=0.01, respectively). Sodium nitroprusside and isoproterenol reduced ICJ pressure (P=0.004, P=0.02, respectively). In the presence of L-NAME, the early inhibitory ileo-ICJ response was abolished, while early and late inhibitory responses were abolished by further addition of propranolol but not by the addition of hexamethonium, atropine, prazosin or yohimbine. The excitatory colo-ICJ response was replaced by inhibition in the presence of L-NAME. We concluded that: (1) the porcine ICJ displays myogenic tone which is influenced by excitatory muscarinic and inhibitory nitrergic and beta adrenergic pathways (2) an inhibitory ileo-sphincteric reflex mediated by nitrergic and beta adrenergic postganglionic neural pathways (3) both excitatory and inhibitory neurogenic colo-sphincteric reflexes exist, and the excitatory pathway involves nitrergic neurotransmission.

Adrenergic alpha-Antagonists↗

Laboratory and animal model evaluation of the Cryotech LCS 2000 in hepatic cryotherapy.

Hepatic cryotherapy is increasingly used in the treatment of patients with multiple hepatic metastases, particularly from colorectal cancer. The Cryotech LCS 2000 system, with insulated shaft-circulated liquid nitrogen probes, was designed for this purpose and was evaluated on the bench and in an animal model. The 9-mm probe was considerably more effective than the 5-mm probe when judged on time to create an iceball of a given diameter. The use of thawing gas reduced the time until the probe could be removed from 25 to 5 min but heated gas only produced a further reduction of 2 min. In the animal model, significant reduction in treatment times occurred with vascular inflow occlusion. The zone of necrosis as a percentage of the original iceball diameter was significantly higher following a twin freeze/thaw cycle. The relationship of the edge of the iceball to the eventual zone of hepatic necrosis was studied using different unabsorbable markers. India ink and sutures proved unreliable but a Teflon cannula was more successful and the margin was only of the order of 2 mm. The discrepancy between this observation and the percentage of the original iceball diameter which apparently becomes necrotic (64 and 82%) for single- and double-freeze lesions, respectively, suggests that the cryolesion undergoes shrinkage within 1 month and that the diameter of necrosis underestimates the true zone of destruction.

Animals↗