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.

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.

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.

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.

Salivary gland duct involvement in oral epithelial dysplasia and squamous cell carcinoma.

The clinical implications and prognostic significance of oral dysplastic or cancerous epithelium involving salivary gland ducts have not been previously investigated. Screened routine tissue sections of 1216 cases of oral epithelial dysplasias and squamous cell carcinomas revealed 26 examples (2.14%) that exhibited unequivocal ductal involvement. Ductal involvement was more likely to occur in floor of mouth lesions and in lesions exhibiting severe dysplasia or carcinoma in situ. Clinical follow-up on 23 cases showed that the recurrence rate of the preinvasive lesions that exhibited ductal involvement was equal to that of the squamous cell carcinomas. The depth of ductal dysplasia did not correlate with recurrence rate. These results suggest that the involvement of salivary gland ducts by oral epithelial dysplasias and carcinomas in situ is an uncommon but significant finding. Surgical stripping or ablation of such lesions should extend at least 3 mm below the surface to ensure eradication of these reservoirs of dysplastic cells.

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.

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.

Analgesics in pediatric dental surgery: relative efficacy of aluminum ibuprofen suspension and acetaminophen elixir.

At one and two hours after administration, aluminum ibuprofen provided statistically superior analgesia, compared with acetaminophen and placebo.

Opsonization of Cryptococcus neoformans by human immunoglobulin G: masking of immunoglobulin G by cryptococcal polysaccharide.

Previous studies have shown that attachment of non-encapsulated cryptococci to macrophages is highly dependent on opsonizing immunoglobulin G (IgG) and that cryptococcal polysaccharide inhibits the attachment phase of phagocytosis. We investigated various mechanisms by which cryptococcal polysaccharide might interfere with the opsonizing action of IgG. Cryptococcal polysaccharide did not appreciably prevent binding of opsonizing IgG to the yeast. Furthermore, cryptococcal polysaccharide acted as a noncompetitive inhibitor with respect to the opsonizing action of IgG. These experiments suggested that cell wall-bound IgG is masked in some manner such that it is unable to participate in Fc-mediated phagocytosis. This appeared to be the case, since cryptococcal polysaccharode inhibited agglutination of IgG-opsonized yeast cells by antiserum to IgG. There was good dose-response correlation between the amount of polysaccharide needed to inhibit phagocytosis of non-encapsulated Cryptococcus neoformans and the amount of polysaccharide needed to prevent agglutination of IgG-opsonized cryptococci by antiserum to IgG. The ability of cryptococcal polysaccharide to prevent agglutination of IgG-opsonized cryptococci by antiserum to IgG was lost if dextran, a substance known to enhance agglutination of several particles, was incorporated into the medium.

Opsonization of Cryptococcus neoformans by human immunoglobulin G: role of immunoglobulin G in phagocytosis by macrophages.

The role of immunoglobulin G (IgG) as an opsonin in phagocytosis of Cryptococcus neoformans by macrophages was investigated. Labeling with 125I showed that IgG isolated from normal human serum bound to non-encapsulated C. neoformans. Furthermore, IgG-opsonized cryptococci were agglutinated by anti-serum to IgG heavy chains, indicating that normal human serum contains antibody that will bind to the yeast surface. The IgG isolated from normal serum accounted for all opsonizing activity found in normal human serum, since differences were not noted between the opsonizing activities of whole serum, heat-inactivated serum and purified IgG when these opsonins were compared at equivalent concentrations of IgG. Phagocytosis of IgG-opsonized cryptococci was inhibited by anti-macrophage IgG, a reagent known to block Fc-mediated attachment and ingestion, and by pepsin digestion of opsonizing IgG. Thus, IgG opsonization is an Fc-dependent process. Opsonizing IgG appears to play its major role during the attachment phase of phagocytosis, since antimacrophage IgG blocked attachment of cryptococci to macrophages but could not block ingestion of IgG-opsonized cryptococci that had been allowed to attach to macrophages. Ingestion of opsonized cryptococci was not blocked by 2-deoxy-D-glucose, a reagent known to block Fc-mediated ingestion, thus confirming that IgG has a primary role in attachment and suggesting that ingestion is mediated by a process that is not Fc dependent.