Biomedical subjects

B N Appel

Publications and source records attributed to B N Appel.

At least 19 recordsLinked to original sources

PubMed1996

Loss of heterozygosity of the short arm of chromosomes 3 and 9 in oral cancer.

Loss of heterozygosity (LOH) on chromosomes 3p and 9p has been documented in a variety of malignancies, which suggests the presence of tumor suppressor gene loci on these chromosomes. We have studied 77 oral carcinomas for LOH using 16 microsatellite markers distributed over 5 human chromosomes. Fifty-five (71%) of these tumors showed LOH at one or more loci. A significant proportion of LOH at the informative tumors was observed at chromosomes 3p and 9p: 58% and 48%, respectively. A majority of the tumors showed losses at multiple loci on chromosomes 3p or 9p or on both. Our results suggest that tumor suppressor genes located on the short arms of chromosomes 3 and 9 may be involved in the pathogenesis of oral carcinoma. These regions of deletion observed in oral cancers overlap those reported in other neoplasms. However, we did not find any evidence of these changes in tumor margins with early pathological changes.

Carcinoma, Squamous Cell↗

PubMed1995

Microsatellite instability in oral cancer.

Generalized genomic instability, detected as somatic changes in allele sizes at microsatellite loci in tumors compared to peripheral lymphocyte DNA, is a recently recognized mechanism of mutation in cancer. Such instability results from the somatic loss of DNA mismatch repair capability. Germ-line mutations at DNA mismatch repair loci confer susceptibility to colon cancer in hereditary non-polyposis colorectal cancer. Somatic loss of DNA mismatch repair has been reported in a large variety of other tumor types. Our goal was to determine the frequency of microsatellite instability in a large series of oral tumors. Out of 91 tumors analyzed for microsatellite instability, 6 (7%) showed microsatellite instability. Instability was observed at multiple loci with a range of 50-74% of loci affected. Alterations include both increase (74%) and decrease (26%) in allele sizes. The proportion of alleles affected ranged from 30-58% of all alleles. Our data suggest that somatic genomic instability plays a role in the pathogenesis of a small subset of oral tumors.

Adult↗

PubMed1995

Visualization of INT2 and HST1 amplification in oral squamous cell carcinomas.

Oral squamous cell carcinoma (OSCC) develops along a multistep genetic pathway including loss of tumor suppressor genes and alteration of oncogenes. We characterized seven OSCC cell lines by classical and molecular cytogenetic analysis and fresh tumor and adjacent oral mucosa corresponding to three of the cell lines by molecular cytogenetics. We observed homogeneously staining regions (hsrs) in four of the seven cell lines, at 11q13 in three and at 11q23 and in an unidentified marker chromosome in the fourth. Amplification of band 11q13 occurs in 30-60% of head and neck squamous cell carcinomas. To determine whether INT2 and HST1, both located in band 11q13, are amplified in the tissues and cell lines and to confirm the chromosomal location(s) of the amplification, we used dual-color fluorescence in situ hybridization (FISH) with DNA probes for these genes and the chromosome 11 centromere. We report chromosomal localization of INT2/HST1 amplification in OSCC. Coamplification of INT2 and HST1 was detected in the hsrs in cultured tumor cells from the four hsr-containing tumors and in directly harvested tumor cells, which were available from only two of these tumors. Amplification was not present in tumors lacking hsrs or adjacent oral mucosa corresponding to any of the seven tumors. The observation of amplification in fresh tumor cells suggests that the amplification was present in the patients, may play a key role in the development and/or progression of OSCC, and is not due to karyotypic evolution in vitro. The absence of amplification in the adjacent mucosa suggests that 11q13 amplification is a relatively late event in OSCC tumorigenesis.

Biopsy↗

PubMed1989

Toxicity testing of sealants: a tissue implant study.

The toxicity of pit and fisure sealants implanted into the subcutaneous tissues of guinea pigs was tested using the protocol for toxicity testing derived from the ADA/ANSI Document No. 41, 1982. The materials tested were Delton autopolymerized and photopolymerized, and Concise White autopolymerized and photopolymerized. After two weeks, reactive fibrosis and mild to moderately severe foreign body reactions were noted. After 12 weeks, only thin fibrous walls infiltrated occasionally by small numbers of chronic inflammatory cells were observed. The results of this investigation appear to indicate that following subcutaneous implantation of a pit and fissure sealant, a foreign body reaction will most likely take place during the first two weeks, but will be resolved by 12 weeks. Furthermore, than an initial reactive fibrosis will give way to a thin fibrosis wall by 12 weeks, and the initial inflammatory response will subside. It can also be stated that in this study, Delton and Concise White sealant materials produced similar tissue reactions, and that there were few differences between materials which were autopolymerized or photopolymerized.

Animals↗

PubMed1988

Acute nonlymphocytic leukemia, monocytic variant. Report of a case.

This report documents a case of a patient presenting unusual oral features of one of the rarer variants of acute nonlymphocytic leukemia, a malignancy whose oral manifestations may be the first indication of the presence of an underlying blood dyscrasia. The findings at the initial appointment and the patient's progress for the following 13 months until his death are presented. Initial suspicion of the clinical symptoms and an immediate, subsequent hospital hematology report established the diagnosis. The histologic features of a gingival biopsy taken during the oral examination were strongly suggestive of leukemia. Since the leukemias may imitate other oral conditions, especially various diseases of the periodontium, it is of paramount importance that the dental clinician recognize their clinical manifestations. As future treatment modalities improve, the dental clinician is seeing more leukemic patients in remission as well as more cases that have relapsed.

Biopsy↗

PubMed1985

Myoepithelioma of the head and neck: case report and review.

The clinical, light, and ultrastructure features of a myoepithelioma occurring on the hard palate of a 24-year-old woman are presented and compared with 41 myoepithelioma of the head and neck described in the English literature. These 42 tumors (39 benign and 3 malignant) occurred in individuals from 14 to 81 years of age, affected both sexes about equally, and most often presented as a slowly enlarging, asymptomatic mass. The parotid gland and palate were the most common sites of occurrence. The tumors are typically circumscribed and encapsulated, vary from 1 to 5 cm in the greatest dimension, and are composed of spindled and/or plasmacytoid myoepithelial cells. Prognosis correlates with histologic appearance and parallels that of the pleomorphic adenoma. Conservative excision with a margin of uninvolved tissue is curative. The differential diagnosis and histogenic relationship with other closely related neoplasms are discussed.

Adenoma, Pleomorphic↗

PubMed1979

Acquired toxoplasma lymphadenitis.

Toxoplasmosis is a common parasitic infection that is widely distributed throughout the world, including the United States. Its occurrence in the oral cavity, however, is uncommon. This report concerns a case of toxoplasmosis that manifested as an intraoral lymphadenitis in a 14-year-old white girl. The etiology, clinical, microscopic, and laboratory findings, and treatment are reviewed. The importance of recognizing lymphadenopathy as a clinical sign of this disorder is discussed.

Adolescent↗

PubMed1977

Comparative study of vitreous carbon, pyrolytic carbon, pyrolytic graphite/silicon-carbide, and titanium implants in rabbit mandibles.

The purpose of the present investigation was to evaluate the biocompatibility of vitreous carbon, pyrolytic carbon, and pyrolytic graphite/silicon-carbide with rabbit mandibular tissues. Titanium was employed as the control material. Twelve New Zealand albino rabbits were implanted with each of the four materials described. Groups of four animals each were killed at 14 days, 45 days, and 90 days. Block sections containing the implants were then removed from the rabbit mandibles, and representative sections were evaluated histologically. All of the implants elicited similar reactions, including fibrous connective tissue capsule formation, multinucleated phagocytic cells, a mild inflammatory infiltrate, and reactive bone. On the basis of these findings, it appears that further detailed investigations are necessary to elucidate the biologic ramifications of the implantation of carbons in mammalian tissues.

Animals↗

PubMed1977

Clinicopathologic effects of cancer chemotherapeutic agents on human buccal mucosa.

Specimens of buccal mucosa obtained at autopsy from 216 patients were examined for histopathologic alterations. Atrophic oral epithelium was found in thirty cases. A retrospective study of the hospital records revealed that thirteen of these latter patients had been on a cancer chemotherapeutic regimen prior to death. There was a significantly higher incidence of atrophy in the chemotherapy group (p less than 0.001) than in control patients. These findings, as well as the expected inherent susceptibility of rapidly replicating oral epithelial cells to metabolic inhibitors, suggest a causal relationship between oral atrophy and the administration of cancer chemotherapeutic agents. This atrophy may therefore represent a preliminary stage of mucosal alteration that ultimately progresses to the clinical sequelae of stomatitis and oral ulcerations frequently encountered during cancer chemotherapy. Some alternative mechanisms are also discussed.

Adult↗

PubMed1976

Multifocal adenoid cystic carcinoma of the lip.

A 62-year-old Caucasian woman had several distinct and separate adenoid cystic carcinomas which involved both sides of the upper lip. Microscopic examination of the surgical specimens suggested that at least one of these malignant neoplasms arose from a pre-existing basal-cell adenoma.

Carcinoma, Adenoid Cystic↗

PubMed1975

Effect of infection with Trichinella spiralis and BCG on thymic histology.

The histology of mouse thymic tissue was examined following infection with Trichinella spiralis and/or BCG. ICR/CD-1 mice were orally infected with 200 T. spiralis 56 days preceding intravenous administration of 4x10-6 viable BCG. Following assessment of delayed hypersensitive foot pad reactions to BCG, the mice were bled and sacrificed. The thymus was removed from each animal, fixed in 10% neutral buffered formalin, embedded in paraffin and cut in 4 mum sections. Examination of serial sections indicated that T. spiralis and T. spiralis-BCG infections induced distinct anatomical changes within the thymic cortex and medulla, which may be related to previously described functional alterations of the immune system.

Animals↗

PubMed1974