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Biomedical subjects

D J Lewis

Publications and source records attributed to D J Lewis.

At least 91 records · Page 5Linked to original sources
PubMed1984

Spontaneous lesions of the mouse biliary tract.

During the routine histological examination of 2400 aged mice from lifespan carcinogenicity studies a low prevalence of glandular metaplasia of the gall bladder and of the intra-hepatic bile ducts (all associated with cholelithiasis), cholecystitis, cholangitis, papillomatous hyperplasia, papilloma, intra-mural cysts, and focal epithelial ulceration was found. The lesions were found predominantly in female mice and were not treatment related.

Animals↗
PubMed1984

Malignant mastocytoma in mice.

Four cases of spontaneous malignant mastocytoma were found in some 20 000 mice. Only liver and spleen were involved in one case, but there was widespread dissemination in the three other animals. Involvement of peripheral blood was detected in only one mouse. In all cases the neoplastic cells were well differentiated, with abundant metachromatic granules.

Animal Diseases↗
PubMed1984

Spontaneous ovarian neoplasms of the laboratory rat.

A wide range of spontaneous tumors of the ovary are reported in a group of 5903 aged female Sprague-Dawley rats of the CD and CFY strains examined since 1978 in this laboratory. The most commonly observed tumor was the tubular adenoma. Others recorded were tubular adenocarcinoma, papillary cystadenoma, papillary cystadenocarcinoma, a Sertoli's cell tumor, benign and malignant granulosa cell tumors, benign thecal cell tumors, and classical mesotheliomas of ovarian origin. A system of classification and nomenclature of the ovarian tumors from this group is advanced.

Adenocarcinoma↗
PubMed1981

Factors affecting the distribution of tobacco smoke-induced lesions in the rodent larynx.

Tobacco smoke-induced laryngeal lesions were investigated in rats and hamsters exposed for up to 12 weeks. The distribution of epithelial hyperplasia and squamous metaplasia was non-uniform in both species. The influence of laryngeal anatomy, histology (epithelial type) and airflow, together with the characteristics of the smoke itself, on the distribution of these lesions, are discussed.

Animals↗
PubMed1981

Effect of tobacco smoke exposure on rat tracheal submucosal glands: an ultrastructural study.

The ultrastructural appearance of rat tracheal submucosal glands after exposure to tobacco smoke for up to two years is described. Within the mucous cells many of the rough endoplasmic reticulum cisternae were grossly dilated with an accumulation of amorphous, electron-lucent material. The Golgi zones were prominent, and the secretion granules often contained dense cores, and appeared to have coalesced. Histochemically, increased amounts of sulphated mucus were present in exposed rats. Serous, ciliated, and myoepithelial cells were unaffected by smoke exposure.

Animals↗
PubMed1981

Mitotic indices of rat laryngeal epithelia.

The histology and mitotic indices of rat laryngeal epithelia were investigated. Five distinct types of epithelia were found: stratified squamous, squamoid (low squamous), respiratory and two cuboidal forms. Squamous epithelium was present mainly in the cranial portion of the larynx, whereas the respiratory type was mostly located in caudal regions. One type of cuboidal epithelium often formed intermediate zones between squamous and respiratory areas. Another form of cuboidal epithelium lined the ventral pouch, and the vocal folds were covered by a low squamous or squamoid type. The mitotic index for each type of epithelium was calculated using colchicine and was expressed as the percentage of total epithelial cells of that kind in mitosis. Mitotic indices for laryngeal epithelial types were: 5.6% in squamous epithelium; 2.4% in the squamoid epithelium of the vocal folds; 2.2% in the cuboidal epithelium in the ventrolateral region; 1.5% in the cuboidal epithelium of the ventral pouch, and 0.6% in respiratory epithelium, although in isolated ciliated areas in the lower epiglottis it was considerably higher (2.6%). There were no significant differences between rats examined on different occasions.

Animals↗
PubMed1980

The ultrastructural features of progestagen-induced decidual cells in the rhesus monkey (Macaca mulatta).

Five rhesus monkeys were treated with levonorgestrel-releasing intravaginal rings for 52 weeks. The rings were designed to provide a sustained release of ten times the human dose level of the hormone. Histological examination of the uterine endometrium showed widespread decidualisation of endometrial stromal cells. Ultrastructurally, two distinct cell types were identified: decidual and granular. Some of the decidual cells were ultrastructurally comparable with those reported elsewhere; however, in aproportion of these cells, intracisternal sequestration of the rough endoplasmic reticulum was widespread. The granular cells resembled those described in the metrial gland of rats and, as their name suggests, contained variable numbers of electron-dense granules.

Animals↗
PubMed1980

A quantitative ultrastructural comparison of macrophages from rats exposed to smoke derived from conventional tobacco and a tobacco substitute.

Using an image analysing computer a variety of ultrastructural features from micrographs of alveolar macrophages have been quantified. Macrophages from rats exposed to smoke from conventional tobacco cigarettes, for 6 months, revealed statistically significant changes when compared to controls. The macrophages were larger, rounded with fewer pseudopodia and contained increased numbers of inclusions. There were no statistically significant changes in macrophages from rats exposed to smoke from a tobacco substitute.

Animals↗