We attempted to determine the reliability of surface markers in distinguishing 21 small round cell tumors from lymphoid malignancies. Using immunofluorescence on tumor cell suspensions and immunoperoxidase on fresh frozen sections, we found that specimens of neuroblastoma (n = 7), rhabdomyosarcoma (n = 7), Ewing's tumor (n = 5), and two unclassified small round cell tumors all lacked human HLA-DR antigens. Each of eight tumors tested also lacked common leukocyte antigen (T200). In each of 13 cases studied, neither polyvalent surface immunoglobulin (sIg) nor receptors for sheep erythrocytes (E), complement (EAC), or the Fc portion of IgG immunoglobulin (EA) were found. Conversely, we found HLA-DR and/or T200 antigens, usually one or more receptors for E, EAC, or EA, and not infrequently, monoclonal sIg on malignant cells in each of 42 cases of lymphocytic lymphoma and leukemia. We conclude that study of surface DR and T200 antigens, sIg, and receptors for E, EAC, and EA aids the differential diagnosis of small round cell tumors from lymphocytic lymphoma and leukemia.

The relationship between the primary service area (PSA) of an urban community health center (CHC) program and a federally defined "medically underserved area" (MUA) was assessed. Federal guidelines that most reliably predicted medical underservice were identified. The service area was statistically defined by census tract penetration rates. The MUA was defined by an index of medical underservice (IMU) according to federal parameters of physician supply, poverty level, percentage elderly persons, and infant mortality. An index score was calculated for the county, service area, and each census tract. Analysis by tract determined the most significant discriminating parameters. By excluding two tracts concentrated with managed-care physicians, the service area qualified as an MUA. Tracts that fulfilled MUA and service area criteria were highly associated ( p < 0.0001). Only poverty level and infant mortality were useful discriminating parameters. Federal indicators of demand (elderly population) and supply (physicians) did not adequately address issues to access for the medically underserved in urban neighborhoods. Other parameters that might serve as proxies of care access and underserved are discussed.

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Neighborhood variation in advanced-stage cancer can serve as the basis for efforts to improve access to breast cancer screening.

A peroxidase-antiperoxidase method that demonstrates both free and encysted toxoplasmata in routinely prepared histologic sections is described. This technic and ultrastructural study were employed to confirm the presence of Toxoplasma gondii in the infected tissues of an immunosuppressed patient who had postmortem examination. An immunohistochemical method may be an aid in the diagnosis of toxoplasmosis.