Primary diffuse leptomeningeal primitive neuroectodermal tumor presenting as chronic meningitis.

Primary diffuse leptomeningeal primitive neuroectodermal tumor is a rare meningeal neoplasm which can masquerade as chronic meningitis. While the clinical presentation and radiological features may provide a clue to this condition, meningeal biopsy is essential to clinch the diagnosis. A high index of suspicion and a low threshold for re-evaluating cases of neuroinfection that do not respond to empirical therapy are essential in this scenario. We present the case of a nine year old boy who was initiated on antituberculous treatment for chronic meningitis with hydrocephalus. Meningeal biopsy revealed a primary diffuse leptomeningeal primitive neuroectodermal tumor.

Lymphoid organ size varies among inbred lines 6(3) and 7(2) and their thirteen recombinant congenic strains of chickens with the same major histocompatibility complex.

The objective was to evaluate lymphoid organ size in chickens from a series of 13 recombinant congenic strains (RCS) and their highly inbred parental lines (6(3) and 7(2)). The parental line 6(3) was selected for resistance to tumors induced by Marek's disease virus and avian leukosis viruses, whereas line 7(2) was selected for susceptibility to these tumors. Each RCS on the average contains a random one-eighth of genome from the donor line 7(2). Previous studies have shown that lines 6(3) and 7(2) differ in the size of primary lymphoid organs; i.e., the bursa of Fabricius (BF) and the lobes of the thymus (T) are smaller in line 6(3) than line 7(2). In the current study, the relative size of the T, BF, and spleen was first examined in about 15 males from each of 13 RCS and the 2 parental lines at 60 to 69 d of age. The differences of relative BF, T, and spleen size among the RCS and the parental lines 6(3) and 7(2) differed significantly (P < 0.001). Males and females from 4 RCS and the 2 parental lines were evaluated a second time, and differences in the relative sizes in lymphoid organs among the RCS and parental lines were consistent. In 2 RCS, the size of the T and BF was comparatively large as in line 7(2), leading to the conclusion that different allelic forms at 1 or more loci in these RCS regulate the size of both organs. In 2 other RCS, the BF was large compared with the T, suggesting that allelic forms at some loci in these RCS influence the BF independent of the T. The relative lymphoid organ size among the RCS appeared to cosegregate with the concentration of IgG in the plasma measured previously. The evaluation of genomic variability of these lines is underway, and the RCS are available for research on traits that differ between lines 6(3) and 7(2).

Methods for evaluating and developing commercial chicken strains free of endogenous subgroup E avian leukosis virus.

The genome of nearly all chickens contains various DNA proviral insertions of retroviruses of subgroup E avian leukosis virus (ALVE). However, the elimination or control of ALVE gene expression is desirable to improve productivity, to improve resistance to avian leukosis virus (ALV)-induced tumours, and to develop safer live virus vaccines in chick embryos and cultured chick cells. Restriction fragment length polymorphism and polymerase chain reaction methods are used to define the presence of ALVE genes; and the expression of ALVE in chicken plasma or on cells, and the susceptibility of cells to ALVE is determined by flow cytometry using a specific (R2) antibody. ADOL line 0 chickens have been selected to be free of ALVE genes, while being resistant (i.e. lack receptors to ALVE), but susceptible to exogenous ALV (i.e. ALVA, ALVB, ALVC and ALVJ). To develop improved line 0-type chickens, ADOL line 0 was outcrossed to a commercial line that had one ALVE gene and evidence for ALVE resistance. Rous sarcoma virus (RSV) challenge was used to confirm resistance of F1 chickens to ALVE, and susceptibility of F2 breeders to ALVA and ALVB using test chicks produced by matings to line 7(2). Selected F2 breeders were resistant to ALVE, but susceptible to exogenous ALVA, ALVB, ALVC and ALVJ, based on challenge tests of progeny chick cells using an enzyme-linked immunosorbent assay. The new line, 0(1), has evidence for improved egg size, productivity, fertility and hatchability. Similar procedures may be used for development of productive ALVE free chicken lines with preferred ALV susceptibility traits.