George T. Gallagher

Oral cancer in vivo gene expression profiling assisted by laser capture microdissection and microarray analysis.

Large scale gene expression profiling was carried out on laser capture microdissected (LCM) tumor and normal oral epithelial cells and analysed on high-density oligonucleotide microarrays. About 600 genes were found to be oral cancer associated. These oral cancer associated genes include oncogenes, tumor suppressors, transcription factors, xenobiotic enzymes, metastatic proteins, differentiation markers, and genes that have not been implicated in oral cancer. The database created provides a verifiable global profile of gene expression during oral carcinogenesis, revealing the potential role of known genes as well as genes that have not been previously implicated in oral cancer.

Role of the Adrenal Cortex in Gastric Mucosal Protection by Prostaglandins, Sulfhydryls, and Cimetidine in the Rat

To investigate the possible role of hormones in gastric mucosal protection, the effect of prostaglandin F2 beta, dimercaprol, or cysteamine on ethanol-induced gastric erosions, and of cimetidine on gastric erosions caused by aspirin was studied in intact, adrenalectomized, medullectomized, ovariectomized, or thyroidectomized rats. Cimetidine was administered at a low dose that did not inhibit hydrogen ion secretion. Adrenalectomized animals failed to exhibit the usual mucosal protective response to prostaglandin F2 beta, sulfhydryls, or cimetidine. Ovariectomy or thyroidectomy did not influence mucosal protection with these agents. The inhibition by total adrenalectomy of mucosal protection was not reversed by large intragastric doses or by parenteral administration of prostaglandin F2 beta. Adrenal medullectomy alone significantly diminished (by approximately one-third) ethanol-induced gastric mucosal injury; prostaglandin F2 beta or sulfhydryl drugs produced significant additional protection. Replacement therapy with glucocorticoids (triamcinolone, corticosterone) but not with mineralocorticoids (deoxycorticosterone, 9 alpha-fluorocortisol) restored the cytoprotective effect of prostaglandin F2 beta and sulfhydryls in adrenalectomized rats. The generation of prostaglandin E2- and prostaglandin I2-like activity in the gastric mucosa was unaltered by adrenalectomy. These studies suggest a permissive role for glucocorticoids in gastric mucosal protection induced by prostaglandins, sulfhydryls, and cimetidine.

Eosinophil ablation and tumor development

Tissue eosinophilia in squamous cell carcinoma has long been recognized; however, the role of eosinophils in tumor development remains unclear. Studies have reported both favorable and unfavorable prognoses for patients with tumors exhibiting tumor-associated tissue eosinophilia (TATE). This study seeks to elucidate the potential role of the eosinophil in squamous cell carcinoma development and provide an experimental model for future studies. The carcinogen-induced hamster oral cancer model was found to fulfill these objectives. Eosinophils progressively infiltrate into this carcinogen-induced oral cancer model. We now demonstrate that TATE is completely abolished by the use of an anti-interleukin-5 monoclonal antibody (mAb) preparation, TRFK-5. Clinical observations revealed that TRFK-5-treated hamsters exhibited smaller tumor burden and delayed onset of tumor development. The results suggest that anti-interleukin-5 antibody treatment may delay and/or inhibit tumor development, and that eosinophils may have a tumor-promoting role.

Eosinophil-derived transforming growth factors (TGF-α and TGF-β1) in human periradicular lesions

Inflammatory mediators of periradicular lesions are poorly understood. Transforming growth factors-α and -β 1 (TGF-α and TGF-β 1 ) have been linked with the cellular processes for both soft and hard tissue wound healing. The purpose of this study is to demonstrate the cellular sources of TGF-α and TGF-β 1 mRNA and protein in periapical lesions by in situ hybridization and immunohistochemistry. Nine periapical granulomas and nine periapical cysts were examined. TGF-α mRNA and protein were not detectable in the granulomas examined. However, eosinophils surrounding the periapical cysts demonstrated both TGF-α mRNA and protein. The vast majority of eosinophils present in the periapical granulomas and cysts also demonstrated TGF-β 1 mRNA and protein. Other cells producing TGF-β 1 were lymphocytes, fibroblasts, and monocytes. The presence of wound repair cytokines, such as TGF-α and TGF-β 1 , suggests a mechanism by which the host inflammatory response may participate in the repair and remodeling of periapical tissues.

Cellular Sources of Transforming Growth Factor-Alpha in Human Oral Cancer

Aberrant expression of TGF-a is associated with human malignant oral epithelium. Experiments were initiated to determine the cellular sources of transforming growth factor-alpha (TGF-a) in human oral cancer. Ten freshly resected human oral cancers and four specimens of normal human oral epithelium were studied by in situ hybridization and immunohistochemistry. Tissues were probed with 35S-labeled sense and antisense riboprobes to (i) human TGF-a (hTGF-a), (ii) human epidermal growth factor receptor (EGFR) to determine the distribution of TGF-a responsive cells, and (iii) histone H3 to examine TGF-a and/or EGFRs possible contribution to altered proliferation in transformed epithelium. Results of our experiments showed that TGF-a mRNA could be detected in normal and transformed human oral epithelium. More surprising, we have identified the major source of TGF-a mRNA to be the infiltrating eosinophils. A monoclonal antibody to the mature human TGF-a peptide stained similar areas in normal and malignant specimens. Eosinophils associated with tumors exhibited positive cytoplasmic immunostaining for TGF-a protein. Labeling of EGFR mRNA in human oral epithelium demonstrated uniform labeling of basal layers in normal, hyperplastic, and mildly dysplastic epithelium. In severely dysplastic epithelium and carcinomas (particularly moderate to poorly differentiated types), cellular levels of EGFR mRNA were significantly higher. The profile of altered cellular levels of EGFR mRNA correlated well with the profile of altered proliferation as indicated by H3 mRNA labeling. We hypothesize that the overproduction of EGFR mRNA in tumor epithelium-together with the localized delivery of high amounts of TGF-a by eosinophils at tumor-developing sites-is responsible for the increased proliferation of the tumor epithelium.

Model-based spectroscopic analysis of the oral cavity: impact of anatomy

In order to evaluate the impact of anatomy on the spectral properties of oral tissue, we used reflectance and fluorescence spectroscopy to characterize nine different anatomic sites. All spectra were collected in vivo from healthy oral mucosa. We analyzed 710 spectra collected from the oral cavity of 79 healthy volunteers. From the spectra, we extracted spectral parameters related to the morphological and biochemical properties of the tissue. The parameter distributions for the nine sites were compared, and we also related the parameters to the physical properties of the tissue site. k-Means cluster analysis was performed to identify sites or groups of sites that showed similar or distinct spectral properties. For the majority of the spectral parameters, certain sites or groups of sites exhibited distinct parameter distributions. Sites that are normally keratinized, most notably the hard palate and gingiva, were distinct from nonkeratinized sites for a number of parameters and frequently clustered together. The considerable degree of spectral contrast (differences in the spectral properties) between anatomic sites was also demonstrated by successfully discriminating between several pairs of sites using only two spectral parameters. We tested whether the 95% confidence interval for the distribution for each parameter, extracted from a subset of the tissue data could correctly characterize a second set of validation data. Excellent classification accuracy was demonstrated. Our results reveal that intrinsic differences in the anatomy of the oral cavity produce significant spectral contrasts between various sites, as reflected in the extracted spectral parameters. This work provides an important foundation for guiding the development of spectroscopic-based diagnostic algorithms for oral cancer.

Anatomy-Based Algorithms for Detecting Oral Cancer Using Reflectance and Fluorescence Spectroscopy

Objectives: We used reflectance and fluorescence spectroscopy to noninvasively and quantitatively distinguish benign from dysplastic/malignant oral lesions. We designed diagnostic algorithms to account for differences in the spectral properties among anatomic sites (gingiva, buccal mucosa, etc). Methods: In vivo reflectance and fluorescence spectra were collected from 71 patients with oral lesions. The tissue was then biopsied and the specimen evaluated by histopathology. Quantitative parameters related to tissue morphology and biochemistry were extracted from the spectra. Diagnostic algorithms specific for combinations of sites with similar spectral properties were developed. Results: Discrimination of benign from dysplastic/malignant lesions was most successful when algorithms were designed for individual sites (area under the receiver operator characteristic curve [ROC-AUC], 0.75 for the lateral surface of the tongue) and was least accurate when all sites were combined (ROC-AUC, 0.60). The combination of sites with similar spectral properties (floor of mouth and lateral surface of the tongue) yielded an ROC-AUC of 0.71. Conclusions: Accurate spectroscopic detection of oral disease must account for spectral variations among anatomic sites. Anatomy-based algorithms for single sites or combinations of sites demonstrated good diagnostic performance in distinguishing benign lesions from dysplastic/malignant lesions and consistently performed better than algorithms developed for all sites combined.

Cysteamine-induced adrenocortical necrosis in rats.

Abstract The development of adrenocortical hemorrhagic necrosis following treatment with cysteamine was studied in rats. Increased vascular permeability, originating in the inner cortical layers, resulted in congestion, platelet aggregation, edema, and hemorrhage which, over a 12-hr period, spread outward to the capsule. Paralleling these changes, retrograde emboli of medullary cells were found in the capillaries of the zona reticularis and fasciculata. Subsequently, the lesions progressed to hemorrhagic necrosis. Cysteamine-induced adrenocortical necrosis was significantly suppressed by medullectomy, hypophysectomy, treatment with aminoglutethimide, and somatostatin, while it was moderately reduced by phenoxybenzamine, labetatol, and metyrapone. ACTH and propranolol provided no protection. The lesion may develop through a dual pathway: one mediated via release of catecholamines directly into cortical capillaries, while the other may involve the production of toxic metabolite.

Intraoral liposarcoma: Case report and review of the literature

The purposes of this article are to present a case report of liposarcoma of the tongue and to review the existing literature regarding liposarcomas with intraoral locations.

Secretory Changes Associated with Chemically-Induced Duodenal Ulceration: Simultaneous Measurements of Acid, Pepsin, Base and Pancreatic Enzymes in Rats with Chronic Gastric Fistula

Rats with chronic gastric fistula were used to study gastric and duodenal/pancreatic secretory changes evoked by chemical duodenal ulcerogens. Although the data demonstrate stimulation of gastric output of acid and pepsin by certain doses of cysteamine or propionitrile, cysteamine produced dose-response increases in acid secretion only during the 1st hour following administration. The base output was also elevated at most of the time intervals after cysteamine. Decreased alkaline secretion was only seen following propionitrile injection. Although hyperacidity at the ulcer site may occur during duodenal ulcerogenesis, these results suggest that direct stimulation of acid-pepsin secretion or depression of pancreatic alkaline output are not the primary mechanisms explaining the ulcerogenic action of cysteamine and propionitrile.