Bruce J. Baum

Subjective reports of xerostomia and objective measures of salivary gland performance

This study involves collecting saliva under unstimulated and stimulated conditions and asking standardized questions of 100 patients with xerostomia. The study examines which questions are useful in identifying and predicting current major salivary gland output deficiency or dysfunction.

Xerostomia and the geriatric patient

Saliva is essential for the preservation of oral‐pharyngeal health, and disorders of salivary physiology are associated with numerous oral and pharyngeal problems, particularly in older people. Although salivary function is remarkably intact in healthy aging, medical problems, medications, and head and neck radiotherapy can cause salivary dysfunction and complaints of xerostomia among older people. Sjögrens syndrome, an autoimmune exocrinopathy, is the most common medical disease associated with salivary dysfunction. Medications with anticholinergic side effects will impair salivary output, and head and neck radiotherapy for cancer will cause permanent destruction of salivary glands. Treatments for salivary problems are based upon establishing a diagnosis, protecting oral and pharyngeal health, stimulating remaining glands, and replacing lost salivary fluids.

Radioprotectors and Mitigators of Radiation-Induced Normal Tissue Injury

The article reviews agents in clinical use or in development as radioprotectors and mitigators of radiation-induced normal tissue injury.

Clinical Science Evaluation of Stimulated Parotid Saliva Flow Rate in Different Age Groups

The production of stimulated parotid saliva was examined in 208 adults, aged 23-88 yr. Among men and women, taking no prescription medication, there was no diminution of stimulated parotid fluid output with increased age. Of subjects taking medication, post-menopausal women (but not older men) produced stimulated saliva at rates significantly lower than their non-medicated counterparts.

Basic Biological Sciences Unstimulated and Stimulated Parotid Salivary Flow Rate in Individuals of Different Ages

Both unstimulated and stimulated parotid saliva samples were collected from 85 healthy, unmedicated individuals between the ages of 23 and 81 years. There were no significant differences in flow rate related to age with either unstimulated or stimulated secretion.

Neurotransmitter Control of Secretion

It is very well established that the principal control of salivary secretion is derived from autonomic innervation. Transmission of a neural signal to a salivary gland acinar cell occurs chemically via neurotransmitters, the first messengers of a secretory response. Neurotransmitters bind to specific cell surface receptor proteins, an event which activates precise transduction mechanisms which then transfer the neural signal to the inside of the cell. There are two major transduction mechanisms operative in salivary gland acinar cells. One involves the generation of cAMP, the other involves the breakdown of plasma membrane polyphosphoinositides. For both mechanisms, the appropriate stimulated receptor activates a second plasma membrane protein, termed an N (or G) protein. The N protein requires GTP to activate an enzyme (adenylate cyclase or phospholipase C), which then catalyzes the formation of a second messenger (cAMP and inositol trisphosphate/diacylglycerol, respectively). This action provides the intracellular signal for secretory events (protein, fluid, electrolyte secretion) to begin.

Differentiation of human bone marrow-derived cells into buccal epithelial cells in vivo: a molecular analytical study

BACKGROUND Adult bone marrow-derived (BMD) cells could be used to repair damaged organs and tissues, but the intrinsic plasticity of these cells has been questioned by results of in-vitro studies suggesting that such cells might fuse with other cells giving the appearance of differentiation. We aimed to determine whether fusion events are important in vivo. METHODS To test whether BMD cells can colonise an epithelial tissue and differentiate there without fusion, we did in-situ hybridisation with Y and X chromosome probes labelled with 35-sulphur or digoxigenin, or labelled fluorescently. We did immunohistochemistry with anticytokeratin 13 along with fluorescence in-situ hybridisation to identify Y-chromosome positive buccal epithelial cells in cheek scrapings obtained from five females who had received either a bone-marrow transplant or an allogeneic mobilised peripheral-blood progenitor-cell transplant (enriched in CD34+ cells) from male donors. FINDINGS When examined 4-6 years after male-to-female marrow-cell transplantation, all female recipients had Y-chromosome-positive buccal cells (0.8-12.7%). In more than 9700 cells studied, we detected only one XXXY-positive cell (0.01%) and one XXY cell (0.01%), both of which could have arisen when an XY cell fused with an XX cell. INTERPRETATION Male BMD cells migrate into the cheek and differentiate into epithelial cells, an occurrence that does not depend on fusion of BMD cells to recipient cells. This finding might be an example of transdifferentiation of haemopoietic or stromal progenitor cells. Plasticity of BMD cells could be useful in regenerative medicine.

Clinical management of salivary gland hypofunction and xerostomia in head-and-neck cancer patients: Successes and barriers

The most significant long-term complication of radiotherapy in the head-and-neck region is hyposalivation and its related complaints, particularily xerostomia. This review addresses the pathophysiology underlying irradiation damage to salivary gland tissue, the consequences of radiation injury, and issues contributing to the clinical management of salivary gland hypofunction and xerostomia. These include ways to (1) prevent or minimize radiation injury of salivary gland tissue, (2) manage radiation-induced hyposalivation and xerostomia, and (3) restore the function of salivary gland tissue damaged by radiotherapy.

POLARIZED DISTRIBUTION OF KEY MEMBRANE TRANSPORT PROTEINS IN THE RAT SUBMANDIBULAR GLAND

Abstract Immunofluorescence labelling and confocal microscopy were employed to examine the polarized distribution of several membrane transport proteins believed to be essential for salivary secretion in the rat submandibular gland. The Na+/K+-ATPase, Na+/H+ exchanger isoform 1 (NHE1), and the secretory Na+/K+/2Cl–cotransporter isoform were all found in the basolateral membranes of acinar and intralobular duct cells. Anion exchanger isoform 2 (AE2) was found only in the basolateral membranes of acinar cells, while AE1 was absent from glandular epithelial cells. Aquaporin 5 was detected in the apical membranes of acinar cells, while the cystic fibrosis transmembrane conductance regulator was found only in apical membranes of intralobular duct cells. NHEs 2 and 3 were found in the apical membranes of both acinar and intralobular duct cells. Our results are generally consistent with the expected distribution of most transporters based on previous physiological and pharmacological experiments. However, the apical localization of NHEs 2 and 3, and the presence of the secretory isoform of the Na+/K+/2Cl–cotransporter in intralobular duct cells were not predicted.

Pilocarpine for the treatment of xerostomia associated with salivary gland dysfunction

A double-blind placebo-controlled study was conducted to evaluate the efficacy of orally administered pilocarpine in treating oral dryness caused by salivary gland hypofunction. At low dosages, pilocarpine increased the production of saliva by parotid and submandibular and/or sublingual glands and relieved the sensation of oral dryness. The quantity and composition of pilocarpine-stimulated secretions were similar to saliva produced in response to gustatory stimulation with citrate. In appropriate patients, pilocarpine is a safe, easily administered, effective therapy to relieve xerostomia by increasing natural salivary function.