Biomedical subjects

R C Horn

Publications and source records attributed to R C Horn.

At least 19 recordsLinked to original sources

PubMed2001

Genotoxicity assessment in aquatic environments under the influence of heavy metals and organic contaminants.

The genotoxicity of river water and sediment including interstitial water was evaluated by microscreen phage-induction and Salmonella/microsome assays. Different processes used to fractionate the sediment sample were compared using solvents with different polarities. The results obtained for mutagenic activity using the Salmonella/microsome test were negative in the water and interstitial water samples analysed using the direct concentration method. The responses in the microscreen phage-induction assay showed the presence of genotoxic or indicative genotoxic activity for at least one water sample of each site analysed using the same concentration method. Similar results were obtained for interstitial water samples, i.e. absence of mutagenic activity in the Salmonella/microsome test and presence of genotoxic activity in the microscreen phage-induction assay. Metal contamination, as evidenced by the concentrations in stream sediments, may also help explain some of these genotoxic results. Stream sediment organic extracts showed frameshift mutagenic activity in the ether extract detected by Salmonella/microsome assay. The concentrates evaluated by microscreen phage-induction assay identified the action of organic compounds in the non-polar, medium polar and polar fractions. Thus, the microscreen phage-induction assay has proven to be a more appropriate methodology than the Salmonella/microsome test to analyse multiple pollutants in this ecosystem where both organic compounds and heavy metals are present.

Animals↗

PubMed1976

Primary diffuse microscopical hyperplasia of the parathyroid glands: surgical importance.

In two of 182 patients with verified primary hyperparathyroidism, microscopical hyperplasia was present in all parathyroid glands that were normal in size or only slightly enlarged. All parathyroid glands in another two patients showed microscopical hyperplasia and varied from a normal size of 190 mg. In seven additional patients, microscopical hyperplasia was present in one, several, or all parathyroid glands, which varied in weight from normal to 350 mg. Familial hyperparathyroidism or multiple endocrine neoplasia was evident in five of 11 patients. Contributing to difficulties was the experience in five patients in whom removal of mildly enlarged parathyroid glands corrected hypercalcemia, but definite microscopical abnormalities were not evident by routine histologic study of the glands. Thus, there appears to be a spectrum of abnormalities relative to size and microscopical changes in parathyroid glands of patients with primary hyperparathyroidism. The surgeon should be aware of these patterns of parathyroid hyperplasia that require a search for a fifth parathyroid gland and a subtotal parathyroidectomy.

Adult↗

PubMed1975

Lobular carcinoma of the breast in situ. Are we too radical in its treatment?

Twenty-four patients (average age, 46 years) with 29 instances of lobular carcinoma in situ of the breast have been treated from 1952 to 1971 at the Henry Ford Hospital (incidence, 1%). Six patients had bilateral lesions, one synchronous and 5 metachronous. The initial complaint in 23 of 24 patients was a mass in the breast. Diagnosis was based on permanent histologic section as mammorgraphy and frozen section analysis were inconclusive. Treatment consisted of radical mastectomy in six, modified radical mastectomy in five, and simple mastectomy in 20. All lymph nodes recovered showed no metastatic disease. All patients are alive and well with no evidence of disease. Based on our experience, we recommend a simple mastectomy for treatment of lobular carcinoma in situ with contraleteral bipsy examination in those instances when clinical or roentgenographic evidence suggests a pathologic process.

Adult↗

PubMed1975

The ultrastructure of smooth muscle tumors with a consideration of the possible relationship of glomangiomas, hemangiopericytomas, and cardiac myxomas.

Tumors classified as being of smooth muscle origin by light microscopy were studied with the electron microscope. Their ultrastructure verified the diagnosis in all of the seven leiomyomas but in only eight of the twelve (66 percent) tumors that were finally classified as leiomyosarcoma. The discrepancy of the light microscopic and ultrastructural findings in these four sarcomas may be due to sampling problems likely to be encountered in poorly differentiated tumors or simply the failure of development of specific ultrastructural features in the face of a characteristic growth pattern at the light microscopic level. Among other tumors that have been considered to be of smooth muscle origin--hemangiopericytoma, glomangioma, and cardiac myxoma--only the glomangioma showed ultrastructure features identical to those of smooth muscle.

Adolescent↗

PubMed1974