M Simon

To investigate chromosomal events that underlie formation and progression of meningiomas, we have examined a set of 18 benign (WHO grade I), 15 atypical (grade II), and 13 anaplastic/malignant (grade III) meningiomas for loss of heterozygosity (LOH) on chromosomes 1p, 6p, 9q, 10q, and 14q. Frequent loss of loci on these chromosomes was seen in grade II and grade III tumors, specifically, 14q (II and III, 47 and 55%), 1p (40 and 70%), and 10q (27 and 40%). In contrast, LOH for these loci was infrequent in benign meningiomas, specifically, 14q (0%), 1p (11%), and 10q (12%). The smallest common regions of deletion that could be defined were 14q24-q32, 1p32-pter, and 10q24-qter. These observations indicate the likely presence of tumor suppressor genes in these regions that are involved in the development of WHO grade II and grade III meningiomas. Because LOH for loci on chromosomes 1p and 10q was found in tumors of all grades and because the frequency of LOH in all three regions increased with tumor grade, these results would support a model for the formation of aggressive meningiomas through tumor progression.

The literature apropos of the degradation of ceramics and ceramic-coated metal systems in physiological media is reviewed. Both in vitro and in vivo studies are involved. Generally, ceramics suffer losses of mechanical strength with time in physiological media, and ceramic-metal bonds lose adherence. Carbons seem to be exceptions to this rule. The theory with regard to the mechanisms associated with the said degradation is still in a primitive stage of development. The development of more meaningful experiments than those now in vogue is needed. Effects of material character and the nature of the environment-material interface upon the strength degradation must be investigated.

PRIMARY carcinoma of the trachea is a comparatively rare neoplasm encountered in the tracheobronchial tree. A search of the literature to 1949 uncovered but 211 cases. One of us (M. R. G.) reported 1 case in 1936, and this present case is his second in twenty-five years of observation. This infrequent occurrence prompts the report of this case. A perusal of the literature discloses only fifteen papers dealing with the subject, and three of these, by Culp¹in 1938, Ellman and Whittaker²in 1947 and Engler³in 1948, present excellent reviews of the subject. From the pathologic point of view these tumors are found to involve mostly the distal third of the trachea, in the posterior wall, with frequent extension to the lateral wall on either side. Histologically, they may be classified in three groups: squamous cell carcinoma, adenocarcinoma and basal cell carcinoma. The squamous cell type