F. Michael Beck

Kinetics of glucocorticoid response to restraint stress and/or experimental influenza viral infection in two inbred strains of mice

The murine model of influenza viral infection was used to evaluate the effects of restraint stress on pathogenesis and survival in inbred strains of mice. We recently reported that restraint stress was associated with an enhanced probability of survival in one strain of inbred mouse, DBA/2, and not in another, C57BL/6. Those studies suggested that the protective mechanism(s) of stress on mortality in the DBA/2 mice might be attributable to elevated levels of circulating glucocorticoids. Therefore, daily levels of plasma glucocorticoids were measured during influenza viral infection in both these strains. The present studies demonstrated that influenza infection itself is perceived as a stressor in both C57BL/6 and DBA/2 mice as evidenced by elevated plasma glucocorticoid levels within 48 h of infection. However, augmentation of glucocorticoid levels was not seen in the DBA/2 mice that were also subjected to restraint stress during the course of infection. Thus, corticosterone levels alone did not account for the enhanced survival seen in this group of animals.

Restraint stress differentially affects the pathogenesis of an experimental influenza viral infection in three inbred strains of mice

Genetic variation in the response to stress may play a critical role in susceptibility to inflammatory diseases and development of the immune response. Experimental influenza viral infection was used to study the effects of restraint stress (RST) on pathogenesis and development of the immune response. Three inbred strains of mice (C57BL/6, DBA/2, and C3H/HeN) were infected with influenza A/PR8 and subjected to repetitive cycles of RST during development of the immune response. RST diminished cellular immune and inflammatory responses in all three strains; yet only the DBA/2 strain demonstrated RST-associated reduction in influenza viral-induced mortality.

Osteointegration of implants in radiated bone with and without adjunctive hyperbaric oxygen

A study was undertaken to evaluate the integration of endosseous implants in rabbit tibias that had received a tumoricidal dose of radiation. The effect of hyperbaric oxygen on integration in this compromised situation was also evaluated. Despite clinical and radiographic evidence of success of all implants, there was a significant decrease in amount of histologic bony integration of implants placed in the tibias that had received radiation therapy when compared to contralateral control implants. Adjunctive hyperbaric oxygen therapy significantly improved the amount of histologic integration of implants placed within the radiated tibias evaluated at 10 and 16 weeks after placement. Hyperbaric oxygen was also associated with better soft tissue wound healing in the radiated surgical site. Increased integration time significantly improved the amount of histologic integration in the animals that did not receive hyperbaric oxygen.

Smile esthetics from the layperson’s perspective

INTRODUCTION Computer-based smile esthetic surveys based on slider technology allow more precise control of variables and the possibility of obtaining continuous data. Variations in the perception of smiles from different facial perspectives have not been resolved. The objective of this study was to quantify the ideal and the range of acceptable values for smile variables judged by laypersons from a full-face perspective for comparison with lower-face data. METHODS Mirrored and symmetric male and female full faces previously determined by peers to be of average attractiveness were used. Ninety-six laypersons judged these smile variables: smile arc, buccal corridor fill, maxillary gingival display, maxillary midline to face, maxillary to mandibular midline discrepancy, overbite, central incisor gingival margin discrepancy, maxillary anterior gingival height discrepancy, incisal edge discrepancy, and cant. The judges manipulated the variables using adjustable image technology that allowed the variable to morph and appear continuous on a computer monitor. Medians for each smile variable were compiled, and the Fleiss-Cohen weighted kappa statistic was calculated to measure reliability. Multiple randomization tests with adjusted P values were used to compare these data with those for lower-face views. RESULTS Reliability ranged from 0.25 for ideal overbite to 0.60 for upper midline to face, except for upper and lower buccal corridor limits, which each had a kappa value near 0. There were no statistically significant differences between the ratings of male and female raters. The following variables showed statistically and clinically significant differences (>1 mm) when compared with the lower-face view: ideal smile arc, ideal buccal corridor, maximum gingival display, upper to lower midline, and occlusal cant. Although the smile arc values differed because of model lip curvature variations, the principle of tracking the curve of the lower lip was confirmed. For the full-face view, the raters preferred less maximum gingival display, less buccal corridor, more upper to lower midline discrepancy, and less cant of the occlusal plane. CONCLUSIONS Reliability was fair to moderate with the exception of the buccal corridor limits. Most variables showed no clinically meaningful differences from the lower-face view. The acceptable range was quite large for most variables. Detailed knowledge of the ideal values of the various variables is important and can be incorporated into orthodontic treatment to produce an optimal esthetic smile.

STRESS-INDUCED CHANGES ATTRIBUTABLE TO THE SYMPATHETIC NERVOUS SYSTEM DURING EXPERIMENTAL INFLUENZA VIRAL INFECTION IN DBA/2 INBRED MOUSE STRAIN

The murine model of influenza viral infection was used to evaluate the effects of restraint stress on pathogenesis and survival in the DBA/2 inbred strain of mice. Restraint stress has been associated with an enhanced probability of survival during influenza infection in this strain of mouse. Previous studies suggested that the protective mechanism(s) of stress on mortality might be attributable to elevated levels of circulating glucocorticoids. Subsequent work demonstrated that corticosterone levels alone could not account for the enhanced survival seen in the DBA/2 mice. The present studies examined the role of catecholamines in behavioral stress during influenza infection. It appears that glucocorticoids may play a primary role in trafficking and restriction of inflammation, while catecholamines may play role in limiting activation of virus-specific effector cells. The studies presented here suggest that the interplay between these two physiological response mechanisms needs to be coordinated to optimize development of the immune response to an infection.

Influence of radiation therapy on oralCandida albicans colonization: A quantitative assessment

An increase in quantity of oral Candida albicans was documented in patients receiving head and neck radiation therapy during and after therapy, as assessed by an oral-rinse culturing technique. The amount of the increase was greater in denture wearers and directly related to increasing radiation dose and increasing volume of parotid gland included in the radiation portal. A significant number of patients who did not carry C. albicans prior to radiation therapy developed positive cultures by 1 month after radiation therapy. The percentage of patients receiving head and neck radiation therapy who carried C. albicans prior to radiation therapy did not differ significantly from matched dental patient controls.

Expression of the serine protease DESC1 correlates directly with normal keratinocyte differentiation and inversely with head and neck squamous cell carcinoma progression

As part of ongoing studies aimed at identifying the molecular events involved in head and neck squamous cell carcinoma progression, we recently isolated a novel serine protease, DESC1. This study was conducted to further characterize DESC1.

Transforming growth factor-alpha overexpression in proliferative verrucous leukoplakia and oral squamous cell carcinoma: an immunohistochemical study.

Proliferative verrucous leukoplakia is a unique type of oral leukoplakia that has a high risk of malignant transformation. The aim of this study was to examine the expression of transforming growth factor-alpha in proliferative verrucous leukoplakia, oral squamous cell carcinoma, and normal mucosa. Transforming growth factor-alpha, a potent mitogen, is known to play an important role in various neoplasms including oral squamous cell carcinoma. Immunohistochemical localization of transforming growth factor-alpha in archival paraffin-embedded sections was performed with commercially available monoclonal antibodies. Ten cases each of normal mucosa, proliferative verrucous leukoplakia, and oral squamous cell carcinoma were stained. Quantification of the staining intensity, expressed as the cytoplasmic optical density, was done with the Roche Image Analysis System. The data were statistically analyzed with the one-way analysis of variance and Tukey tests. Notably, the mean cytoplasmic optical density of proliferative verrucous leukoplakia was significantly higher than the mean cytoplasmic optical density of normal mucosa (p < 0.01). The mean cytoplasmic optical density of proliferative verrucous leukoplakia was slightly higher than that of oral squamous cell carcinoma, however, this difference was not significant (p > 0.05). The mean cytoplasmic optical density values demonstrate that increased transforming growth factor-alpha immunoreactivity occurs in proliferative verrucous leukoplakia and oral squamous cell carcinoma relative to normal mucosa.

Factors associated with orthodontists’ assessment of difficulty

The difficulty of achieving an ideal or normal occlusion might lie in the pretreatment occlusion, patient-associated factors, and the treatment. The purpose of this study was to identify factors that were related to the treating orthodontists posttreatment categorization of a case as difficult or easy. Ten orthodontists each identified 10 easy cases and 10 difficult cases that they had treated. The initial malocclusion was measured with the peer assessment rating (PAR) index and the index of orthodontic treatment need (IOTN). Patient and treatment information was obtained from the treatment records. Statistical analysis with parametric or nonparametric testing was performed. Difficult cases had greater severity and need before treatment and greater residual malocclusion and need after treatment. Difficult cases had more chart entries for problems with hygiene and compliance. They were more likely to have had extractions and changes in treatment plan. Difficult cases also required more appointments and a longer treatment duration. Three logistic regression models were developed based on malocclusion severity, patient characteristics, and treatment characteristics. The models support a correlation between greater pretreatment malocclusion severity, 1-phase treatment, and the designation as a difficult case. This study supports a model in which malocclusion severity and factors associated with the patient and the treatment contribute to an orthodontists categorization of a case as easy or difficult.

Distinctive Pattern of Glial Fibrillary Acidic Protein Immunoreactivity Useful in Distinguishing Fragmented Pleomorphic Adenoma, Canalicular Adenoma and Polymorphous Low Grade Adenocarcinoma of Minor Salivary Glands

Objectives Immunohistochemistry (IHC) can be helpful in the diagnosis of minor salivary gland neoplasms including those that have been incisionally biopsied or fragmented during surgery that do not contain key diagnostic features on hematoxylin and eosin sections. IHC has been used as an adjunct to distinguish among many salivary gland neoplasms using both qualitative and quantitative methods. The objective of this study was to determine whether a distinctive immunoreactivity staining pattern to GFAP can be consistently observed among three selected minor salivary gland neoplasms and thus serve as a diagnostic adjunctive procedure. Study Design Glial fibrillary acidic protein (GFAP) reactivity was examined among 78 minor salivary gland neoplasms: 27 canalicular adenomas (CAA), 21 pleomorphic adenomas (PA) and 30 polymorphous low grade adenocarcinomas (PLGA). Each case was evaluated by two oral and maxillofacial pathologists (OMP) blinded to the diagnosis. Consensus was reached on the pattern of GFAP reactivity among the neoplastic cells and on the similarities and differences among the cases. Results Ninety-six percent (96%) of CAAs demonstrated a distinctive linear immunoreactive pattern among cells in proximity to connective tissue interface. All (100%) PAs demonstrated diffuse immunopositivity within tumor cells. All (100%) PLGAs showed little or no intralesional reactivity and no peripheral linear immunoreactivity. Additional challenge cases were examined by outside OMPs to demonstrate the utility of these findings. Conclusions This study demonstrates that the pattern of GFAP immunoreactivity may be an adjunct to diagnosis among PA, CAA and PLGA. The pattern of distinctly linear GFAP immunoreactivity at the tumor/connective tissue interface in CAA has not been reported previously. This distinctive feature may permit the pathologist to differentiate among CAA, PA and PLGA when an incisional biopsy and/or fragmentation cause key diagnostic features to be absent. Because each of these neoplasms requires a different treatment approach, this can be of major significance.