Dennis R. Trune

Tumor angiogenesis, the p53 antigen, and cervical metastasis in squamous cell carcinoma of the tongue

A more accurate method of detecting nodal disease in squamous cell carcinoma of the tongue is needed so that treatment of the neck with its associated morbidity can safely be reserved for patients who actually have metastatic disease. Tumor angiogenesis and the expression of the p53 antigen—which have each been shown to be predictive of metastasis in breast and colon cancer, respectively—are examined for their ability to predict neck metastasis in tongue cancer. Fifty-seven patients with T1 and T2 squamous cell carcinoma of the oral tongue, whose neck disease was examined by dissection or by 2-year follow-up, were studied. Twenty-eight patients (49%) were node positive and 29 patients (51%) were node negative. The primary tumors were immunohistochemically stained for the p53 antigen and for factor VIII, which allowed the blood vessels within the tumor to be quantitated. The mean vessel counts per × 200 high-power field were 59.8 and 61.5 for node-positive and node-negative patients, respectively (p = 0.8). Node-positive patients showed overexpression of p53 43% of the time, vs. 61% for node-negative patients (p = 0.17). Multivariate analysis confirmed that no difference in tumor angiogenesis or the expression of the p53 antigen was found between tumors that had metastasized and those that had not. Therefore neither tumor angiogenesis nor the p53 tumor marker is clinically useful in determining lymph node metastasis in these patients.A more accurate method of detecting nodal disease in squamous cell carcinoma of the tongue is needed so that treatment of the neck with its associated morbidity can safely be reserved for patients who actually have metastatic disease. Tumor angiogenesis and the expression of the p53 antigen--which have each been shown to be predictive of metastasis in breast and colon cancer, respectively--are examined for their ability to predict neck metastasis in tongue cancer. Fifty-seven patients with T1 and T2 squamous cell carcinoma of the oral tongue, whose neck disease was examined by dissection or by 2-year follow-up, were studied. Twenty-eight patients (49%) were node positive and 29 patients (51%) were node negative. The primary tumors were immunohistochemically stained for the p53 antigen and for factor VIII, which allowed the blood vessels within the tumor to be quantitated. The mean vessel counts per x200 high-power field were 59.8 and 61.5 for node-positive and node-negative patients, respectively (p = 0.8). Node-positive patients showed overexpression of p53 43% of the time, vs. 61% for node-negative patients (p = 0.17). Multivariate analysis confirmed that no difference in tumor angiogenesis or the expression of the p53 antigen was found between tumors that had metastasized and those that had not. Therefore neither tumor angiogenesis nor the p53 tumor marker is clinically useful in determining lymph node metastasis in these patients.

Perivascular-resident macrophage-like melanocytes in the inner ear are essential for the integrity of the intrastrial fluid–blood barrier

The microenvironment of the cochlea is maintained by the barrier between the systemic circulation and the fluids inside the stria vascularis. However, the mechanisms that control the permeability of the intrastrial fluid–blood barrier remain largely unknown. The barrier comprises endothelial cells connected to each other by tight junctions and an underlying basement membrane. In a recent study, we found that the intrastrial fluid–blood barrier also includes a large number of perivascular cells with both macrophage and melanocyte characteristics. The perivascular-resident macrophage-like melanocytes (PVM/Ms) are in close contact with vessels through cytoplasmic processes. Here we demonstrate that PVM/Ms have an important role in maintaining the integrity of the intrastrial fluid–blood barrier and hearing function. Using a cell culture-based in vitro model and a genetically induced PVM/M-depleted animal model, we show that absence of PVM/Ms increases the permeability of the intrastrial fluid–blood barrier to both low- and high-molecular-weight tracers. The increased permeability is caused by decreased expression of pigment epithelial-derived factor, which regulates expression of several tight junction-associated proteins instrumental to barrier integrity. When tested for endocochlear potential and auditory brainstem response, PVM/M-depleted animals show substantial drop in endocochlear potential with accompanying hearing loss. Our results demonstrate a critical role for PVM/Ms in regulating the permeability of the intrastrial fluid–blood barrier for establishing a normal endocochlear potential hearing threshold.

Issues, indications, and controversies regarding intratympanic steroid perfusion

Purpose of reviewOffice-based intratympanic inner ear steroid perfusion (ITPs) treatment for Ménières disease, autoimmune inner ear disease, and sudden sensorineural hearing loss has been expanding over the past 10–15 years, yet remains controversial. The purpose of this review is to examine the current literature of basic science and human studies of ITPs treatment. Recent findingsAnimal studies exist regarding the delivery, distribution, biochemical, and microbiological changes in the inner ear post ITPs. However, few clinical studies exist on ITPs treatment in sudden sensorineural hearing loss and even less in treating Ménières disease. There are no consistent studies regarding drug delivery methods, type, and concentration of steroids. Moreover, there are no studies comparing ITPs results to the natural history of Ménières disease. SummaryITPs has impacted otology and neurotology practice due to increased utilization. A sound understanding of the basic science and clinical studies is needed to establish long-term efficacy of ITPs in controlling hearing loss in Ménières disease by comparison to its natural history, as well as, potential application to other disorders.

Intratympanic injection of dexamethasone: time course of inner ear distribution and conversion to its active form.

Hypothesis: Intratympanically injected dexamethasone 21-phosphate is converted to its active form dexamethasone in the inner ear and follows the distribution of the glucocorticoid receptor. Background: Although dexamethasone is routinely delivered intratympanically for hearing loss, we know little of its inner ear pharmacokinetics. Dexamethasone 21-phosphate is the pharmaceutical compound available for injection, but it must be converted to its biologically active form (dexamethasone) to bind to the glucocorticoid receptor. Therefore, the current study was conducted to determine the time course of dexamethasone 21-phosphate movement from the middle ear into the inner ear, its conversion to dexamethasone, and the distribution of both forms relative to the glucocorticoid receptor. Methods: BALB/c mice were injected intratympanically with the prodrug dexamethasone 21-phosphate and inner ears collected at postinjection times ranging from 5 minutes to 7 days. Ears were immunohistochemically stained for dexamethasone 21-phosphate, dexamethasone, and the glucocorticoid receptor. Results: Both forms of dexamethasone were seen in the inner ear within 15 minutes, reaching their highest staining intensity at 1 hour. Neither drug was seen after 24 hours. The strongest staining occurred in the spiral ligament, organ of Corti, spiral ganglion, and vestibular sensory epithelia. Distribution of the drug paralleled locations of the glucocorticoid receptor except in the stria vascularis marginal cells, which stained heavily for the receptor but not the drug. Conclusion: Dexamethasone rapidly travels from the middle ear into the inner ear and converts to its active form. The drug distribution follows that of the glucocorticoid receptor. However, it probably has little impact on ear tissues after 24 hours.

Effects of topically applied biomaterials on paranasal sinus mucosal healing.

Background Recently, nasal packing made of absorbable biomaterial has become increasingly popular. Although absorbable packs are effective for hemostasis, their impact on healing mucosa is unknown. Some have felt that a biocompatible sinus dressing actually may enhance healing, particularly in areas where the mucosa has been stripped. The aim of this study was to determine the effect of topical MeroGel and FloSeal on paranasal sinus mucosal healing in a rabbit model. Methods Bilateral maxillary sinuses of 12 New Zealand white rabbits were surgically opened and stripped of mucosa. The left maxillary sinus of six rabbits had sterile saline-soaked MeroGel placed in the antrum, and the other six rabbits received FloSeal. The right maxillary sinuses of all 12 animals were stripped and otherwise untreated to serve as stripped controls. The animals were killed at 2 weeks and specimens were examined by light microscopy. Results MeroGel-treated mucosa showed extensive fibrosis of the basal lamina and lamina propria, complete loss of surface epithelium, and loss of the mucociliary blanket. There was minimal resorption of the MeroGel, and MeroGel fibers were frankly incorporated into the regenerated epithelium, associated with an exuberant lymphocytic infiltrate. FloSealtreated mucosa showed similar fibrosis of the basal lamina and lamina propria with loss of the mucociliary blanket, although to a lesser degree than the MeroGel- treated group. FloSeal showed similar incorporation into the healed mucosa with lymphocytosis. Controls showed expected submucosal gland reduction, lamina propria fibrosis, and loss of cilia, but the lamina propria fibrosis seen in the MeroGel and FloSeal groups was markedly more prominent. Conclusion In a rabbit model, MeroGel and FloSeal appear to increase reactionary fibrosis of healing mucosa. These agents also appear to be incompletely resorbed and grossly incorporated into healing tissue. Mucosal healing may be impaired by the application of these agents.

The relative importance of head size, gender and age on the auditory brainstem response

Correlations between the ABR (auditory brainstem response) and subject characteristics of gender, age, and head diameter were established in simple and multiple regression analyses of normal hearing individuals. The simple regression tests demonstrated that head diameter and gender were significantly correlated with the latencies and amplitudes of waves I, III, and V and the I-V and III-V interpeak intervals. In nearly all cases, head diameter correlated more highly with the ABR waves than did gender. Males had longer latencies than females with comparable head diameter, suggesting that factors other than head size are differentiating them. Age was significantly correlated only with the latency of wave III. All significant subject variables also were compared simultaneously in a multiple regression analysis to determine their order of significance and relative contributions to the ABR wave latencies. This permitted the establishment of regression equations for each wave latency to predict the ABR with measurable subject characteristics.

Mineralocorticoid receptor mediates glucocorticoid treatment effects in the autoimmune mouse ear.

The standard treatment for many hearing disorders is glucocorticoid therapy, although the cochlear mechanisms involved in steroid-responsive hearing loss are poorly understood. Cochlear dysfunction in autoimmune mice has recently been shown to be controlled with the mineralocorticoid aldosterone as effectively as with the glucocorticoid prednisolone. Because aldosterone regulates sodium, potassium, and other electrolyte homeostasis, this implied the restoration of hearing with the mineralocorticoid was due to its impact on cochlear ion transport, particularly in the stria vascularis. This also suggested glucocorticoids may be controlling hearing recovery in part through their binding to the mineralocorticoid receptor in addition to their glucocorticoid receptor-mediated anti-inflammatory and immunosuppressive functions. Therefore, the aim of the present study was to better delineate the role of the mineralocorticoid receptor in steroid control of hearing in the autoimmune mouse. Spironolactone, a mineralocorticoid receptor antagonist, was administered to MRL/MpJ-Fas(lpr) autoimmune mice in combination with either aldosterone or prednisolone to compare their hearing and systemic disease with mice that received either steroid alone. ABR thresholds showed either aldosterone or prednisolone alone preserved hearing in the mice, but spironolactone prevented both steroids from maintaining normal cochlear function. This suggested both steroids are preserving hearing through the mineralocorticoid receptor within the ear to regulate endolymph homeostasis. The spironolactone treatment did not block normal glucocorticoid receptor-mediated immune-suppression functions because mice receiving prednisolone, either with or without spironolactone, maintained normal body weights, hematocrits, and serum immune complexes. Thus, reducing systemic autoimmune disease was not sufficient to control hearing if mineralocorticoid receptor-mediated functions were blocked. It was concluded the inner ear mineralocorticoid receptor is a significant target of glucocorticoids and a factor that should be considered in therapeutic treatments for steroid-responsive hearing loss.

Breakdown of stria vascularis blood-labyrinth barrier in C3H/lpr autoimmune disease mice☆☆☆★

Sensorineural hearing loss related to autoimmune disease is a well-recognized condition, although the exact pathophysiologic mechanisms remain unclear. One current theory postulates immune complex-induced interference with blood-labyrinth barrier integrity in the stria vascularis. The C3H/lpr autoimmune mouse was chosen to study the permeability of capillaries in the stria vascularis because this mouse model has demonstrated abnormalities of the stria vascularis and shifts in the auditory brain stem response threshold during active disease. C3H/lpr mice with active disease were compared with younger mice without disease, as well as age-matched C3H/HeJ control mice. The mice were injected with the tracer ferritin and examined by transmission electron microscopy to evaluate the integrity of the capillary tight junctions in the stria vascularis. Four of five mice with active disease were noted to have extensive leakage of ferritin into the perivascular tissues. Neither the young, disease-free autoimmune mice nor the nonautoimmune control mice demonstrated vessel leakage. Thickening of the basement membrane was also noted in the diseased animals. The results imply that active disease leads to a breakdown in the blood-endolymph barrier, which could underlie the hearing loss accompanying autoimmune and other immune diseases.

Histochemical localization of carbonic anhydrase in the inner ear

Carbonic anhydrase was histochemically located in chinchilla inner ear tissues. A strong carbonic anhydrase reaction was observed in the spiral ligament cells, Boettchers cells, the external sulcus cells, and the stria vascularis (intermediate and/or basal cells). The enzymatic reaction was also positive in the supporting cells of all vestibular sensory epithelia, as well as in the dark cells and transitional cells of the utricle and saccule. Some epithelial cells of the endolymphatic sac were also positive. It is speculated that this enzyme may be involved in: 1) ionic or fluid regulation of the endolymph, 2) removal of CO2 from the inner ear tissue near the sensory cells, and 3) otoconia formation and maintenance.

Variables affecting the auditory brainstem response: Audiogram, age, gender and head size

Correlations between the ABR (auditory brainstem response) and the variables of hearing loss, gender, head size and age were determined in simple and multiple regression analyses in 334 ears. The stepwise multiple regression analyses for waves I, III and V of the ABR was used to determine the relative importance of the variables. Regression equations were calculated for the latency of each wave. Wave I latency for all subjects is best predicted by hearing threshold at 8 kHz, gender and age, in that order. Wave III latency depends upon hearing threshold at 4 kHz, age and gender. The latency of wave V is best predicted by gender, age and head diameter with threshold at 4 kHz being of minor importance. The I-V interval depends upon head diameter and threshold at 8 and 4 kHz with age of minor importance. Hearing loss at 8 kHz would shorten the I-V interval, while a loss at 4 kHz would be expected to lengthen the interval. Correlations of these variables with the amplitude of I, III and V are also described. Latency and amplitude are correlated with different subject variables suggesting differences in their generation.