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Biomedical subjects

T McGaw

Publications and source records attributed to T McGaw.

9 recordsLinked to original sources
PubMed2001

Submandibular gland transfer: a new method of preventing radiation-induced xerostomia.

OBJECTIVE: Radiation-induced xerostomia is a significant morbidity of radiation therapy in the management of patients with head and neck cancers. We have recently reported a method of transfer of one submandibular gland to the submental space in a small pilot series of eligible surgical patients. The submental space was shielded during postoperative radiation therapy. The transferred gland continued to function after the completion of radiation therapy and none of the patients developed xerostomia. The purpose of this article is to present the technique of submandibular gland transfer in detail and to evaluate the postoperative survival and function of the transferred submandibular glands. DESIGN: Prospective clinical trial. METHODS: The submandibular gland was transferred on eligible patients as part of their surgical intervention. The patients were followed clinically, with salivary flow and radioisotope studies. RESULTS: We performed the surgical transfer of the submandibular salivary gland in 24 of 25 patients placed on the protocol. All the glands survived transfer and functioned well postoperatively as demonstrated on the salivary flow and the radioisotope studies. The surgical transfer was relatively simple and added 45 minutes to the surgical procedure. There were no complications attributed to the submandibular gland transfer. CONCLUSIONS: We have successfully demonstrated that the submandibular gland can be surgically transferred to the submental space with its function preserved. The gland seems to continue functioning even after radiation therapy with the appropriate shielding. This surgical transfer procedure has the potential to change the way we currently manage patients with head and neck cancer.

Adult↗
PubMed2000

Submandibular salivary gland transfer prevents radiation-induced xerostomia.

BACKGROUND: Xerostomia is a significant morbidity of radiation therapy in the management of head and neck cancers. We hypothesized that the surgical transfer of one submandibular salivary gland to submental space, outside the proposed radiation field, prior to starting radiation treatment, would prevent xerostomia. METHODS: We are conducting a prospective clinical trial where the submandibular gland is transferred as part of the surgical intervention. The patients are followed clinically, with salivary flow studies and University of Washington quality of life questionnaire. RESULTS: We report early results of 16 patients who have undergone this procedure. Seven patients have finished and 2 patients are currently undergoing radiation treatment. In 2 patients, no postoperative radiation treatment was indicated. Two patients are waiting to start radiation treatment and 2 patients refused treatment after surgery. The surgical transfer was abandoned in 1 patient. All of the transferred salivary glands were positioned outside the proposed radiation fields and were functional. The patients did not complain of any xerostomia and developed only minimal oral mucositis. There were no surgical complications. CONCLUSIONS: Surgical transfer of a submandibular salivary gland to the submental space (outside the radiation field) preserves its function and prevents the development of radiation-induced xerostomia.

Adult↗
PubMed2000

Dental Students with Hepatitis B e Antigen: A Survey of Canadian Dental Schools.

BACKGROUD: Health care workers who are e-antigen-positive carriers of hepatitis B virus have become a significant focus of concern in the development of public health policy. In cases of needle-stick injury, the risk of transmission of HBV has been estimated at 60-fold greater if the carrier is positive for e antigen than if the carrier does not have the e antigen. Debate continues regarding proposed public health policies to restrict e-antigen-positive health care workers from performing "exposure-prone procedures". Given the potentially greater risk of disease transmission to patients and the potential career implications for infected students, dental schools must responsibly address the issue of dental students and dental school applicants who have the hepatitis B e antigen. This paper reviews the controversies surrounding this issue and reports a survey of Canadian dental schools.

Journal Article↗
PubMed1998

Nitric oxide relaxes human myometrium by a cGMP-independent mechanism.

The role of intracellular guanosine 3',5'-cyclic monophosphate concentration ([cGMP]i) in nitric oxide (NO)-mediated relaxations in the uterus has become controversial. We found the NO donor S-nitroso-L-cysteine (CysNO) to potently (IC50 = 30 nM) inhibit spontaneous contractions in the nonpregnant human myometrium. CysNO treatment increased [cGMP]i significantly (P < 0.001), and this increase was blocked by the guanylyl cyclase inhibitors methylene blue (10 microM) or LY-83583 (1 microM); however, pretreatment with these guanylyl cyclase inhibitors failed to block CysNO-mediated relaxations. Intracellular cAMP concentrations were not altered by treatment of tissues with 10 microM CysNO. Incubation with the cGMP analogs 8-bromo-cGMP or beta-phenyl-1,N2-etheno-cGMP did not significantly affect spontaneous contractility. Pretreatment of tissues with charybdotoxin [a calcium-dependent potassium channel (BK) blocker] completely reversed CysNO-induced relaxations. We conclude that NO is a potent inhibitor of spontaneous contractile activity in the nonpregnant human uterus and that, although guanylyl cyclase and BK activities are increased by NO, increases in [cGMP]i are not required for NO-induced relaxations in this tissue.

Aminoquinolines↗
PubMed1988

Assessment of intraperitoneal adhesion formation in a rat model: can a procoagulant substance prevent adhesions?

Previous studies have shown oxidized cellulose to decrease adhesion formation in rats. A recent report showed a decrease in adhesions after application of a fibrin sealant containing thrombin, fibrinogen, and aprotinin, raising the question of whether procoagulants block adhesions by something other than a mechanical barrier effect. To assess the value of a procoagulant in preventing adhesion formation, we compared the efficacy of thrombin with that of oxidized cellulose in decreasing postoperative adhesions in rats. Eighty-five Sprague-Dawley rats underwent midline abdominal incisions and subsequent removal of a small area of right anterior abdominal wall peritoneum. Defects were left open or were closed with interrupted sutures and then treated with thrombin, oxidized cellulose, or nothing. Results obtained at postmortem seven days later showed a decrease in adhesion number and severity among animals treated with oxidized cellulose. No such effect was noted in the thrombin group. No treatment increased adhesion formation. We conclude that although oxidized cellulose appears to be of some benefit in decreasing postoperative adhesion formation in the rat, thrombin alone shows no similar effect. Further conclusions regarding adhesion induction, histologic correlates of adhesion formation, and validity of some methods of adhesion analysis are also addressed.

Animals↗
PubMed1987

Cyclosporin-induced gingival overgrowth: correlation with dental plaque scores, gingivitis scores, and cyclosporin levels in serum and saliva.

Gingival overgrowth, dental plaque, and gingivitis were assessed by means of standardized semiquantitative indices in thirty renal transplant patients undergoing immunosuppression with cyclosporin-A (Cy-A). Radioimmunoassay techniques were used to determine Cy-A in serum samples and in parotid, submandibular, and whole saliva samples from each patient. A significant positive correlation was found between gingival overgrowth scores and both dental plaque and gingivitis scores. A significant positive correlation was found between whole-saliva Cy-A and both plaque and gingival overgrowth scores. No such correlation was found when parotid Cy-A or submandibular Cy-A was considered. This was attributed to differences in saliva-collection methods, and a possible role of dental plaque as a local reservoir of Cy-A is proposed.

Adult↗