Subungual squamous cell carcinoma presenting with minimal nail changes: A factor in delayed diagnosis?

Squamous cell carcinoma of the nail bed is a relatively uncommon tumour that may be diagnosed only after considerable delay. The first case presented is a 79-year-old man with a history of discomfort and discoloration affecting the right thumbnail of 3 years duration. The second case is a 70-year-old man who presented with a recurrent, offensive discharge from beneath the left thumbnail of 40 years duration. Clinical examination of the affected digits revealed minor nail abnormalities. The presence of tumour was fully apparent only after removal of the nail plate and inspection and biopsy of the nail bed. The cases demonstrate that subungual squamous cell carcinoma may present with prolonged symptoms and a deceptively benign appearance. The importance of consideration of the possibility of malignancy, removal of the nail plate for inspection of the nail bed and appropriate biopsy is emphasized.     

Human breast cancer in vivo: H-1 and P-31 MR spectroscopy at 1.5 T

To assess the potential of in vivo magnetic resonance (MR) spectroscopy for breast cancer, hydrogen-1 and phosphorus-31 MR spectra of five malignant human breast tumors were compared with those of unaffected breast tissue. The water-to-fat ratio was high in the tumors (average, 2.2) but low in the unaffected tissue (average, 0.3). The P-31 spectrum of normal breast tissue showed low levels of phosphomonoesters (PMEs), inorganic phosphate, phosphodiesters (PDEs), and ATP. In addition, an intense phosphocreatine (PCr) signal was observed in breast tissue of young women: The relative intensities of the PCr and ATP signals had a mean value of 1.9. The tumor spectrum showed elevated levels of PMEs, Pi, and PDEs, while no PCr was seen (PCr/ATP less than 0.2). In two breast cancers treated with radiation therapy, resulting in a decrease of tumor volume of more than 50%, a similar change in the tumor P-31 spectrum was observed: An intense PCr signal developed (PCr/ATP = 1.1). Control experiments indicated that the appearance of PCr after radiation therapy was the result of a radiation-induced metabolic change in the tumor itself.     

Contractile proteins participate in release of erythroid growth regulators from mononuclear cells

We have investigated the role of contractile proteins of circulating mononuclear cells in generation of membrane-associated, erythroid growth regulatory molecules. Lymphocytes and monocytes were incubated under serum-free conditions without and with cytochalasin B, cytochalasin D, or colchicine, and effects on positive and negative erythropoietic activities were determined in cell membranes and in surface membrane vesicle-rich pellets and supernatants of dialyzed medium conditioned by the cells. In serum-free cultures of human bone marrow, plasma membranes and exfoliated membrane-derived vesicles from cytochalasin-treated lymphocytes lost their capacity to support the formation of erythroid bursts, while monocyte membrane-associated inhibitory activity was abolished by preincubation with cytochalasin. In contrast, membrane-associated activities of colchicine-treated cells were unaffected. Cytochalasin-induced alterations of membrane regulatory molecules were observed in a dose-dependent fashion over a wide range of concentrations (1 to 100 micrograms/mL) tested. However, the capacity of membrane vesicle-free supernatants of medium conditioned by lymphocytes or monocytes was unaffected by cytochalasins, regardless of drug concentration used. Lysates of cytochalasin B-treated cells inhibited the activity of deoxyribonuclease I to a greater degree than did lysates of untreated cells, suggesting that the relative amount of monomeric actin is increased in the cytoplasm of treated cells. Furthermore, results of experiments with D-glucose and with cytochalasin D suggest that cytochalasin effects are independent of alterations in glucose metabolism. The data indicate that expression of plasma membrane- associated regulators is sensitive to agents that block polymerization of actin. They raise the possibility that changes in distribution of actin between unpolymerized and filamentous pools may influence the organization and/or function of mononuclear cell surface-associated erythroid regulatory molecules.