Biomedical subjects

P C Fox

Publications and source records attributed to P C Fox.

At least 91 records · Page 5Linked to original sources

PubMed1992

Effects of ionizing radiation and beta-adrenergic stimulation on the expression of early response genes in rat parotid glands.

There is little known about the regulation of gene expression in rat parotid glands after exposure to ionizing radiation. The present studies investigate the effects of in vivo ionizing radiation, with subsequent stimulation of beta-adrenergic receptors by isoproterenol, on parotid gland function and on the expression of the early response genes, c-fos, c-jun, and jun B. Ionizing radiation diminished parotid gland weight and saliva output. Treatment of irradiated rats with isoproterenol increased the gland weight to levels similar to those in nonirradiated rats. However, such treatment had no effect on saliva output as indicated by measurements of parotid salivary flow rate. Irradiation alone increased the expression of c-fos, c-jun, and jun B. The combination of irradiation and isoproterenol had an additional effect on the levels of c-fos and jun B mRNAs and proteins particularly at earlier experimental times (1 to 8 h). Isoproterenol alone induced high levels of c-fos and jun B mRNA but not of c-jun mRNA. However, c-jun mRNA was induced markedly by radiation and 8 h of isoproterenol treatment, indicating a combined effect on c-jun gene expression. These observations suggest that the expression of the proto-oncogenes c-fos, c-jun, and jun B is probably regulated through differential signal transduction pathways which may be activated by these external stimuli and may be associated with functional changes induced in the rat parotid gland by ionizing radiation and by ionizing radiation and isoproterenol.

Animals↗

PubMed1992

c-myc mRNA expression in minor salivary glands of patients with Sjögren's syndrome.

c-myc protooncogene is implicated in the pathogenesis of B cell lymphoid malignancies and high levels of c-myc mRNA expression are observed in activated blood mononuclear cells. Sjögren's syndrome (SS) is characterized by lymphocytic infiltrates of exocrine glands, remarkable B cell hyperreactivity and a strong predisposition to B cell neoplasia. In this study, c-myc protooncogene mRNA expression in 29 labial minor salivary gland biopsies from patients with primary SS and 15 controls was examined using in situ hybridization histochemistry. Two 40mer oligonucleotides from the 1st and the 2nd exon of the c-myc gene, labeled with 35S, were used as probes. To detect the origin of the cell hybridized with a c-myc probe, a combined immunochemistry in situ hybridization histochemistry technique was used. High c-myc mRNA expression was detected on acinar epithelial cells. c-myc did not correlate with c-fos and c-jun protein expression. Stronger c-myc mRNA expression was detected in labial salivary glands of patients with longer disease duration (p less than or equal to 0.002) and more intense T lymphocyte infiltrates (p less than 0.05) although these patients revealed no hypergammaglobulinemia. No correlation was observed between c-myc mRNA and B lymphocyte monoclonicity or lymphoma. In conclusion, strong c-myc mRNA expression was observed on epithelial cells of labial salivary glands from patients with primary SS. Our findings may indicate the presence of a reactivated virus hosted in these cells.

Adult↗

PubMed1991

Oral mucosal appearance is unchanged in healthy, different-aged persons.

Oral mucosal status in 182 different-aged, healthy, community-dwelling persons was evaluated. Ninety-four men and 88 women, ranging in age between 20 and 95 years, participated in this study. Oral mucosal status was assessed according to both subjective complaints and a semiquantitative clinical rating scale. No changes in either criterion were detected with increasing age. Oral mucosal status of the older subjects of this study was comparable to that found in a previous study with a randomly enrolled, noninstitutionalized older population in Iowa. The results of this study suggest that aging per se does not lead to changes in the appearance of oral mucosa.

Adult↗

PubMed1991

Magnetic resonance imaging of canine salivary glands after ductal ligation and stimulation by pilocarpine.

We performed magnetic resonance imaging in six dogs after submandibular ductal ligation on one side, followed by secretory stimulation with intraperitoneal injection of pilocarpine (5 mg/kg). On the images obtained after ductal ligation but before stimulation, there was no significant change in signal intensity on either side. After injection of pilocarpine the signal intensity of the ligated gland increased significantly (p less than 0.01) in T2-weighted images and nonsignificantly in inversion recovery images, and remained constant in T1-weighted images. Significant (p less than 0.01) volume increases of the glands after ligation and stimulation were measured for the T1, T2, and inversion recovery protocols. These findings likely reflect the retention of saliva caused by pilocarpine stimulation and the absence of drainage through the obstructed duct. The results indicate that the T2-weighted images obtained after pilocarpine stimulation may be useful for studying patients with disturbance of major salivary gland function and may provide an objective basis for the noninvasive diagnosis of unilateral stenosis.

Animals↗

PubMed1991

An investigation of parotid gland function and histopathology in autoimmune disease-prone mice of different age groups.

This work aimed to characterize parotid gland function in autoimmune disease-prone murine strains (MRL/n, MRL/l and NZB/W) in relation to increasing age and to relate the extent of functional impairment to the intensity of histopathologic changes observed at the different ages. Pilocarpine-stimulated parotid saliva was collected to assess salivary flow rate and composition. Parotid tissue was then removed for histopathologic assessment. Parotid flow rates were not significantly reduced in autoimmune strains compared to controls but were reduced with age in NZB/W mice and in males of the C57 (control) strain. Age-related salivary compositional changes were present in MRL/l mice and in male NZB/W mice. Focal lymphocytic adenitis increased with age in prevalence and intensity in both sexes. The functional and histopathologic changes were not closely correlated. These results suggest that the parotid gland of autoimmune disease-prone mice provides only a poor replication of the salivary changes in human Sjögren's syndrome. Nevertheless, both the functional and histopathological changes developing in these strains, even though of limited extent, are significantly influenced by age.

Aging↗

PubMed1991

Interactions of the salivary and gastrointestinal systems. I. The role of saliva in digestion.

Considerable evidence now demonstrates that saliva and its components have multiple functions in the GI tract. Saliva aids in bolus formation; it lubricates, protects and cleanses the pharyngeal and esophageal mucosa. Salivary bicarbonate buffers esophageal acid in common reflux. Normal salivary flow decreases the duration of acid contact with esophageal mucosa, an important factor in the development of GERD. If salivary flow is depressed or if the esophagosalivary reflex is lost, a patient may be predisposed to develop GERD. Salivary EGF stimulates GI mucosal proliferation via a direct lumenal effect in the esophagus and stomach. The salivary enzymes LL and salivary amylase initiate fat and starch digestion. They are particularly significant in patients with pancreatic insufficiency such as neonates and patients with cystic fibrosis.

Amylases↗

PubMed1991

Interactions of the salivary and gastrointestinal systems. II. Effects of salivary gland dysfunction on the gastrointestinal tract.

Salivary gland dysfunction is uniformly detrimental to the oral cavity. Its effects on the GI tract have begun to be explored. Dry mouth is a common complaint among older adults, probably due to systemic disease and its therapy rather than the aging process per se. Evaluation of complaints of dry mouth should include medical history, sialometry and physical examination. Numerous medications can elicit drug-induced xerostomia. Patients who have received radiation therapy to the head and neck region often have permanent radiation-induced xerostomia, which has been linked to esophagitis. SS is an autoimmune systemic exocrinopathy resulting in irreversible salivary gland dysfunction. SS has numerous GI manifestations, including dysphagia, temporal defects of deglutition, esophageal dysmotility, gastritis, pancreatitis and liver disease. Management of salivary hypofunction is directed toward preserving the dentition and improving patient comfort. Drug-induced xerostomia is often correctable by altering the therapeutic modality.

Aging↗

PubMed1991

How much saliva is enough? 'Normal' function defined.

Saliva is important for the preservation and maintenance of oral health. It is unclear, however, how much saliva is required to maintain normal oral function. Major salivary gland flow rates, objective measurements of oral health, and subjective complaints of oral problems were assessed in different-aged, healthy persons. Results suggest that the comparison of major salivary gland flow rates of an individual with population standards to identify patients susceptible to the effects of salivary dysfunction is unreliable. Changes in salivary function over time are a more meaningful gauge of the impact of saliva on oral health. The clinician should monitor salivary production to identify patients with declining salivary gland output.

Adult↗

PubMed1991

Saliva and salivary gland alterations in HIV infection.

HIV-1 infection may involve saliva and the salivary glands. The virus may be recovered from the mouth and anti-viral antibodies are found in saliva. Salivary dysfunction after infection ranges from xerostomia to a Sjogren's syndrome-like condition with persistent glandular enlargement and marked secretory hypofunction.

Acquired Immunodeficiency Syndrome↗

PubMed1991

Bacterial infections of salivary glands.

Bacterial infections of the salivary glands are most often seen in the setting of diminished salivary function. In uncompromised individuals, such infections are rare. With the widespread use of prophylactic antibiotics and better maintenance of fluid balance, even the postoperative patient rarely presents with bacterial sialadenitis. The major recent advance in knowledge in this area is the recognition of the pathogenic role of gram-negative facultative anaerobes and strict anaerobic organisms in bacterial infections of salivary glands.

Anti-Bacterial Agents↗

PubMed1991

T cell subpopulations in the labial minor salivary gland histopathologic lesion of Sjögren's syndrome.

The majority of T cells constituting the focal lymphocytic infiltrates in the labial minor salivary glands of patients with Sjögren's syndrome bear the helper phenotype (CD4); activation is expressed by class II (HLA-DR) MHC products. In our immunohistologic study of snap frozen minor salivary gland biopsies from 16 patients with primary Sjögren's syndrome, it was shown that the majority (77%) of the infiltrating T cells exhibit the memory helper/inducer phenotype (UCHL-1) and express LFA-1 molecules. In addition most of the T cells express the alpha beta receptor while only 2.8% express the gamma delta receptor. Our findings suggest that these T cell infiltrates in patients with primary Sjögren's syndrome may explain the intense B lymphocyte hyperreactivity observed in the exocrine glands of patients with Sjögren's syndrome.

Adult↗

PubMed1991

Pilocarpine treatment of salivary gland hypofunction and dry mouth (xerostomia).

We studied the effects of pilocarpine hydrochloride, a para-sympathomimetic agent, on major salivary gland output and subjective responses in 31 patients with salivary hypofunction. Pilocarpine hydrochloride (5-mg capsules, three times daily) was given for 5 months and a placebo was randomly assigned for 1 month in a double-blind fashion. Objective measurements of major salivary gland output, subjective impressions of oral moisture, treatment-related side effects, and a number of physiologic measures were assessed monthly. Pilocarpine significantly increased salivary output in 21 of the 31 patients. Subjective improvement in the feeling of oral dryness, speaking, chewing, and swallowing were reported by 27 individuals. Side effects, while common, generally were mild and tolerable. There were no significant alterations in cardiovascular or other physiologic measures. We conclude that pilocarpine is an effective and safe treatment for salivary gland hypofunction and xerostomia in selected patients. The increase in major gland output provides beneficial natural secretions and relief of oral dryness.

Adolescent↗

PubMed1990

Sjögren's syndrome in patients with primary biliary cirrhosis.

Symptomatology and objective findings of Sjögren's syndrome were evaluated in 38 consecutive patients with primary biliary cirrhosis. Symptoms of Sjögren's syndrome were present in 18 (47.4%) patients, but were severe enough to warrant therapy in only four (10.5%). Nineteen patients consented to evaluation for Sjögren's syndrome, which included Schirmer's I test, measurement of parotid flow rate and serum autoantibodies, labial minor salivary gland biopsy and human leukocyte antigen typing. Histological changes diagnostic of Sjögren's syndrome were present in five patients (26.3%). All five patients had symptoms of Sjögren's syndrome and three had abnormal Schirmer's I tests, but none had corneal ulcerations or decreased parotid flow rates. Results of serological tests and human leukocyte antigen typing were not similar to those described in patients with primary Sjögren's syndrome but were similar to those described in patients with rheumatoid arthritis and Sjögren's syndrome. These findings indicate that Sjögren's syndrome associated with primary biliary cirrhosis is a form of secondary Sjögren's syndrome resembling that associated with rheumatoid arthritis.

Aged↗

PubMed1990

Oral mucosal status and major salivary gland function.

Normal salivary function is considered to be critical for the maintenance of healthy oral mucosa. However, few studies have examined mucosal changes in patients with objectively documented salivary gland performance. In the present report, the mucosal status of 298 subjects being evaluated in a dry mouth clinic was assessed. A complete oral examination was performed and unstimulated and stimulated salivary samples were collected separately from the parotid and submandibular/sublingual glands. Data were analyzed according to diagnosis and salivary output after the assignment of an oral mucosal rating to each subject. In general, the mucosal surfaces were well preserved and infections were not seen. Patients evaluated for Sjögren's syndrome and radiation-induced xerostomia had the lowest salivary gland performance but displayed a mucosal status similar to denture-wearing healthy subjects or patients with normal salivary flow who had idiopathic xerostomia. However, those patients with a total lack of salivary flow rarely had normal-appearing oral mucosa. These results confirm a role for saliva in oral mucosal preservation and also suggest that other factors may act to maintain oral mucosal integrity.

Adolescent↗

PubMed1990

In Vitro Interaction of Nuclear Proteins with the Promoter of Soybean Heat Shock Gene Gmhsp17.5E.

Proteins present in crude nuclear extracts of soybean (Glycine max) plumules were shown to bind in vitro to the 5' flanking sequences of the soybean heat shock gene Gmhsp17.5E. The specificity of binding activity present in extracts from both control (28 degrees C) and heat shocked (40 degrees C) tissues was demonstrated by reciprocal competition experiments using gel mobility retardation assays. Footprinting experiments using DNase I with crude nuclear extracts indicated that a continuous stretch of 5' flanking sequences extending from -40 to -153 was protected from digestion in vitro. Nuclear proteins that were partially purified by heparin agarose chromatography were shown to bind specific TATA-proximal sequences containing the heat shock consensus elements (HSEs) (-73 to -49; -107 to -84) and AT-rich motifs (-119 to -153). Other binding sites within AT-rich sequences (-906 to -888, -868 to 863, -859 to 853, and -841 to -830), distal HSE elements (-568 to -532) and a TATA/dyad (-234 to -207) were also identified by DNase I footprinting of TATA-distal probes. DNA binding activities specific for the HSE and AT-rich sequences were present in nuclear extracts from both control and heat shocked tissues. Both types of binding activity were increased after heat shock treatment; HSE binding increased from 1.8- to 2.7-fold, and binding to AT-rich sequences showed an increase from 1.3- to 1.7-fold.

Journal Article↗

PubMed1990

Histologic assessment of the submandibular glands in autoimmune-disease-prone mice.

Submandibular glands were examined from three autoimmune-disease-prone strains of mice (NZB/W, MRL/l and MRL/n) and controls (C57BL/6J). Focal lymphocytic adenitis was more prevalent and more severe in autoimmune-disease-prone strains than controls and in females than males. Lymphocytic foci were more frequent in older age groups, but female MRL/1 mice exhibited high levels of focal lymphocytic adenitis irrespective of age. Salivary parenchyma was generally well preserved. In the strain-age groups with the highest focal lymphocytic scores proportional acinar volumes were significantly less than in controls. However, the proportion of acinar tissue showed no consistent relation to the severity of focal lymphocytic adenitis across all strains and age groups of either sex. Sexual dimorphism in granular duct prominence was weakened in NZB/W and MRL/l strains compared to controls.

Aging↗

PubMed1990

A method for measuring the flow of saliva from the minor salivary glands.

This investigation evaluated a procedure to measure the quantity of secretion by the minor salivary glands from various locations in the mouth before and after citric acid stimulation. Fourteen healthy non-medicated adults were assessed on each of two morning visits at the same specific areas of the mucosa (labial, buccal, and palatal). During each assessment, an absorbent paper strip was placed on each designated location for 30 s, removed, and its moisture content determined with a calibrated Periotron. Calibration procedures indicated that readings were linearly associated with known saliva volumes and were negligibly influenced by differences in salt concentration and viscosity. At each visit, the buccal flow was significantly greater than those from the lip and palate. The flow from glands in each area was unaffected by a single application of the gustatory stimulant. The mean flow rates at each specified site were similar during the two visits.

Adult↗

PubMed1990

Magainin-like immunoreactivity in human submandibular and labial salivary glands.

Magainins, antimicrobial peptides secreted by granular glands of frog skin, may be related to the high resistance to infections of this epithelial surface. The oral mucosa of healthy individuals is another tissue in which infection is not frequent, probably owing to the activity of potent salivary and mucosal defense mechanisms. To investigate if magainin-like factors are a component of these oral defense mechanisms, human and animal minor (mucosal) and major salivary glands were examined by immunohistochemistry, using a polyclonal rabbit anti-magainin antibody. Cryostat sections of (para) formaldehyde-fixed tissues were incubated with the antibody and then stained with fluorescein-complexed anti-rabbit IgG. Specific staining was observed in the apical portion of the cytoplasm of ductal epithelial cells of human submandibular and labial salivary glands. Diffuse staining was present in submandibular acinar cells. Bovine, rat, hamster, and mouse tissues were unreactive. The presence of magainin-like substances in human salivary gland duct cells is consistent with reports of the occurrence of other biologically active substances in salivary gland ducts.

Adult↗