Convoluted lymphocytic lymphoma in adults: a clinicopathologic entity

Twelve adults had a distinct clinicopathologic type of malignant lymphoma that closely resembles the mediastinal lymphomas of childhood. Nine patients presented with mediastinal masses, and seven had symptoms related to intrathoracic compression. Seven patients presented with or developed leukemia, and in four of these patients the central nervous system (CNS) became involved. Structurally, the tumor cells had a distinctive stippled chromatin pattern, in addition to the characteristic nuclear convolutions. Tumor cells from five patients were studied immunologically, and, in each case, the tumor cells formed rosettes with sheep erythrocytes. The response to combination chemotherapy was rapid and dramatic, but usually transient, with relapse in the CNS or previously involved sites. The above data strongly suggest that these cases represent a distinct clinicopathologic entity that should be treated similarly to childhood leukemia and lymphoma, with intensive multiple agent induction, CNS prophylaxis, possibly radiation therapy to initially involved sites, and prolonged maintenance.

Too old to teach?

The scores obtained by 71 generalpractitioner trainers on a 100-question multiple choice question paper were analyzed in relation to the number of years since the trainer qualified. No evidence was found that older trainers had poorer recall of clinical facts.

The ultrastructure of osteosarcoma. A review of twenty cases

The ultrastructural features of 20 cases of osteosarcoma are discussed. Characteristically, the malignant cells (osteoblasts) contained large quantities of dilated, anastomosing rough endoplasmic reticulum, ofter forming large lakes. Mitochondria were sparse. Similar features are seen in osteoblasts in normal developing bone. Marked ultrastructural similarities of cells from chondrosarcomatous, fibrosarcomatous and typical osteosarcomatous areas of these tumors strongly supports the concept that these neoplastic cells all arise from the same progenitor cell. Malignant giant cells were readily differentiated from benign osteoclasts. The most significant ultrastructural findings were the varying degrees of calcification in the intercellular areas (osteoid), ranging from an extensive dense deposition of hydroxyapatite crystals which obscured the underlying collagen fibers, to focal collectors, or puffs, of slender needle-shaped hydroxyapatite crystals deposited on or along collagen fibers. The earliest apparent evidence of calcification was the presence of small electron-dense particles on or in collagen fibers.

Improved method for the estimation of plasma ammonia by ion exchange

Care in the preparation and preservation of reagents, together with certain modifications in apparatus and technique, have eliminated the difficulties from plasma ammonia analysis. Ammonia contamination from the laboratory atmosphere has not proved an especial hazard, and no major setback has been encountered in the analysis of several thousand specimens over the last few years. The method has been found particularly suited to the performance of the occasional estimation, since, once prepared, all reagents are stable for a considerable time.