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Biomedical subjects

J C Weir

Publications and source records attributed to J C Weir.

At least 19 recordsLinked to original sources
PubMed1997

Atypical cartilage in reactive osteocartilagenous metaplasia of the traumatized edentulous mandibular ridge.

Eighteen cases of reactive osteocartilagenous metaplasia of the edentulous mandibular alveolar ridge forming clinical masses that mimic neoplasms are reported. Although most of these lesions appeared histologically benign, three exhibited atypical microscopic features suggestive of chondrosarcoma. Of those cases that were followed, none of the lesions recurred after simple surgical excision. Because many investigators consider all cartilagenous lesions of the jaws potentially malignant, the importance of recognizing this benign condition is stressed.

Adult↗
PubMed1988

Labial salivary gland tumors.

A study was conducted on labial salivary gland tumors from four oral pathology laboratories. Of the 103 identified tumors, 87 (84.5%) were from the upper lip, whereas 16 (15.5%) were from the lower lip. Of the 87 upper lip tumors, 80 (92.0%) were benign. Forty-three of these were monomorphic adenomas and 37 were pleomorphic adenomas. Seven malignant tumors of the upper lip were as follows: four adenoid cystic carcinomas, two acinic cell carcinomas, and one adenocarcinoma. Of the 16 lower lip tumors, 15 (93.8%) were malignant. Thirteen of these were mucoepidermoid carcinomas and two were acinic cell carcinomas. The only benign lower lip tumor was an intraductal papilloma. These results confirm the findings of previous investigations, showing that minor salivary gland tumors are much more common in the upper lip than the lower lip, but that lower lip tumors are more likely to be malignant.

Adolescent↗
PubMed1988

Effects of excess vitamin A and canthaxanthin on salivary gland tumors.

The effects of feeding semipurified diets supplemented with excess retinyl palmitate (20,000 and 100,000 IU/kg), beta-carotene (250 mg/kg), and canthaxanthin (250 mg/kg) on 7,12-dimethylbenz[a]anthracene (DMBA)-induced salivary gland tumors were studied in rats. None of the dietary supplements had a significant effect on tumor incidence. Tumor weights, however, tended to be lower in rats fed the dietary supplements compared with the controls. The incidence of tumor-bearing rats with large tumors was significantly lower in rats fed canthaxanthin than in the control rats. At termination of the experiment, the levels of vitamin A were higher in plasma, liver, normal salivary glands, and the tumor of rats fed diets supplemented with the higher level of retinyl palmitate. Feeding the canthaxanthin-supplemented diet had the opposite effect on tissue and plasma vitamin A levels. beta-Carotene supplementation was associated with higher vitamin A concentrations in the liver but not in plasma, salivary glands, or the tumor. The levels of beta-carotene were increased in tissues and plasma of rats fed the beta-carotene-supplemented diet. The results suggest that in this experimental model, the diet-induced modification of tissue or plasma vitamin A levels did not have an effect on tumor incidence.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1987

A diagnostic and epidemiologic survey of 15,783 oral lesions.

Tissue specimens submitted to an oral pathology biopsy service during a 17 1/2-year period were studied to determine the types of diagnoses rendered, the general types of pathological processes represented, and the epidemiologic distribution of patients. A total of 15,783 cases were studied. Normal structures were observed in 480 cases, mostly dental follicles, and were eliminated from the study. The remaining 15,303 cases had been diagnosed as pathological entities. A majority of the oral biopsies were taken from either infectious or reactive conditions. Fibromas, periapical granulomas, periodontitis, mucoceles, and radicular cysts were the most frequently encountered lesions. Neoplasms constituted nearly 15% of all the specimens, with approximately 18% of these being malignant. An additional 360 lesions (2.4% of the total number of specimens) harbored dysplasia and might be considered premalignant. The peak age groups represented in these patients were the third through sixth decades of life. More oral biopsies were performed on females than males. A majority of the patients were white. The purpose of this study was to determine the relative frequency of oral lesions that were considered to be of sufficient clinical significance to merit a biopsy. Although this data might be used as a guide for forming clinical impressions about oral lesions, the clinician must always be aware of the possible occurrence of more rare lesions.

Adolescent↗
PubMed1985

Oral malignancy: a regional incidence observed over a 13-year period.

In this study slightly more than two out of every 100 biopsy specimens from the set population of 10,414 specimens showed malignant oral lesions. The most common sites for oral malignancy were the floor of the mouth and the alveolar ridge, respectively. Lesions were most common during the fifth decade of life, followed by the sixth. Eighty-eight percent of the malignant lesions occurred in whites and 12% inn blacks. This does not deviate significantly from the percentage in the total biopsies reported. Of the categories of neoplasms, surface ectodermal neoplasms predominated, followed by salivary and mesenchymal lesions, respectively. There did not appear to be a significant difference in sex incidence.

Adult↗
PubMed1984

Maxillary sinus mucocele. Report of an unusual case.

The maxillary sinus mucocele occupying the entire sinus is rarely reported by dentists. This article discusses one such case diagnosed as an exceptionally large maxillary sinus cyst occupying the whole sinus. Unlike their findings in the medical literature, the authors were unable to find many similar cases reported in the dental literature. The location of these mucoceles necessitates the use of diagnostic radiographs, especially those of the panoramic type. Because etiology is still not fully understood after almost 100 years, the authors suggest and discuss four possible mechanisms of sinus mucocele formation and growth.

Adult↗
PubMed1984

Chemopreventive effects of beta-carotene and 13-cis-retinoic acid on salivary gland tumors.

The chemopreventive effects of beta-carotene and 13-cis-retinoic acid (RA) on chemically induced salivary gland tumors were studied in rats. Young male Sprague-Dawley rats were injected in one of the submandibular salivary glands with 1 mg of dimethylbenzanthracene (DMBA) dissolved in olive oil. The contralateral gland was injected with the vehicle alone. Rats were divided into four groups and were fed ad libitum a semisynthetic diet supplemented with 0 or 100 mg beta-carotene/kg diet, or 20 or 100 mg RA/kg diet. Rats were killed at 22 weeks after the DMBA treatment, and tumors were examined histologically. Tumors were generally found to be squamous cell carcinomas or poorly differentiated neoplasms resembling squamous cell carcinomas. The tumor incidence was slightly lower in rats fed the diet supplemented with beta-carotene. RA had no appreciable effect on tumor incidence. A high activity of gamma-glutamyl transpeptidase was histochemically demonstrated in the tumors. There were some mortalities in the beta-carotene and RA supplemented groups, especially in the group fed high levels of RA. This mortality appeared to be related to vitamin K becoming somewhat limited.

9,10-Dimethyl-1,2-benzanthracene↗
PubMed1982

Periapical actinomycosis. Report of a case and review of the literature.

An analysis of actinomycosis in periapical inflammatory lesions in the English-language literature was carried out. Nineteen cases were found, and an additional case is presented. The most frequent locations for these infections were the maxillary central incisor region and the mandibular first molar region. The average age of the patients was 27.5 years, and a slight male predilection was noted. Formation of draining sinuses, local swelling, and pain were the most common presenting symptoms. Many of the cases were diagnosed following endodontic procedures, suggesting that such procedures might be responsible for introducing the organisms into the periapical tissues or that the organisms might be responsible for some cases of endodontic failure.

Actinomycosis↗