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Biomedical subjects

M G Norman

Publications and source records attributed to M G Norman.

9 recordsLinked to original sources

Regranulation of islets of Langerhans and normalization of in vivo insulin secretion in ob/ob mice treated with oxytetracycline.

Oxytetracycline (OTC) treatment was associated with regranulation of the islet cells and increased pancreatic insulin content in the ob/ob mouse. This was accompanied by an improvement of the in vivo insulin secretory response to glucose. Because of the wide-ranging effects of OTC on other membrane-related functions, it is postulated that this compound may exert ist effect by altering the composition of cellular membranes.

Animals

Case report and ultrastructural study of intracranial embryonal carcinoma.

A case of a primary intracranial embryonal carcinoma, the first with ultrastructural study, is reported. The tumor was associated with precocious puberty in a 6 1/2-year-old female. Characteristic embryoid bodies were present. At the ultrastructural level three cell types were noted: undifferentiated, differentiated, and intermediate types. The undifferentiated showed scanty cytoplasmic organelles and numerous free polysomes, while the differentiated cells contained well-developed mitochondria, Golgi apparatus, rough endoplasmic reticulum, and some contained secretory granules. The intermediate cells possessed dilated and irregularly-shaped mitochondria but still retained large numbers of free polysomes. The authors suggest that intracranial germ cell tumors be named in conformity with germ cell tumors in other sites, and that terms such as "ectopic pinealoma" and "atypical teratoma of the pineal" be used no longer.

Brain Neoplasms

The ultrastructure of Sturge-Weber disease.

Five infantile and one adult case of Sturge-Weber disease were studied pathologically. The calcification occurring under the leptomeningeal angiomatosis increased with advancing age. Light and electron microscopy of two cases showed the smallest, and therefore possibly the earliest, calcifications occurred in perithelial cells. It is hypothesized the cause of calcification is anoxic injury to endothelial, perithelial and possibly glial mitochondria due to stasis and abnormal vessel permeability in the cerebral vessels composing the Sturge-Weber angioma.

Adult

Lissencephaly.

The first reported case of lissencephaly resulting from a consanguinous union strengthens the supposition that in some cases, it is transmitted as an autosomal recessive trait. Comparison of this case with a sporadically occurring case of lissencephaly, with different cortical morphology, suggests that lissencephaly may be an example of either varying gene expressivity or genetic heterogeneity. Lissencephaly and pachygyria may eventually be shown to be due to different causes, some inherited, some acquired. The classical examples of lissencephaly are different morphologically from a case in which antenatal cytomegalovirus infection had produced a small smooth brain. This suggests that antenatal viral infections are destructive rather than teratogenic.

Abnormalities, Multiple

Bilateral dissecting aneurysms of the intracranial internal carotid arteries in an 8-year-old boy.

Nontraumatic intracranial dissecting aneurysms have rarely been reported as the cause of acute infantile and childhood hemiplegia. The present case is unique because dissecting aneurysms occurred bilaterally in two clinically distinct episodes. A recent dissecting aneurysm of the right intracranial internal carotid artery was present with a healed dissecting aneurysm of left internal carotid artery in an 8-year-old boy.

Aneurysm