Glucan is a potent reticuloendothelial stimulant whose immunobiological activity is mediated, in part, by an increase in the number and function of macrophages. In studying the role of glucan as a mediator of antibacterial activity, we attempted to ascertain the ability of glucan to modify the mortality of mice with experimentally induced Gram-positive bacteremia, and to enhance antibacterial defenses in rats as denoted by serum lysozyme and phagocytic activity. After intravenous administration of glucan, serum lysozyme concentrations were increased approximately sevenfold over control concentrations. The increase in serum lysozyme appeared to parallel the glucan-induced increase in phagocytosis and induced hyperplasia of macrophages. Prior treatment of mice with glucan significantly enhanced their survival when they were challenged systemically with Staphylococcus aureus. These studies indicate that glucan confers an enhanced state of host defense against bacterial infections.
In earlier studies of the cytogenetic characteristics of leukemic lymphoblasts from children with pre-B-cell acute lymphoblastic leukemia (ALL), we concluded that certain chromosomal abnormalities explain, in part, the increased presence of high-risk features at diagnosis and the less favorable response to therapy among patients with this immunologic subclass of ALL. With extended follow-up and a larger patient population, we have further evaluated the biologic and clinical aspects of pre-B leukemia. Of 686 cases of ALL with adequate immunophenotyping, 150 were classified as pre-B cell. Seventy-seven (69%) of the 112 pre-B cases with fully banded karyotypes had a translocation. The t(1;19) accounted for 28 (25%) of these pre-B cases and 31 (6.5%) of all 480 consecutively banded ALL cases. Three (2.6%) of the pre-B cases had a novel dicentric (7;9)(p1?3;p11) translocation. A t(9;22)(q34;q11) and a t(4;11)(q21;q23) were observed in seven (6%) and three (2.6%) of the cases, respectively. Within the pre-B subgroup, comparison of t(1;19) cases (n = 28) with those having other translocations (n = 49) or no identifiable translocations (n = 35) indicated that higher leukocyte counts (P = .002), absence of DNA indexes greater than 1.16 (P = .02), higher serum lactate dehydrogenase levels (P less than .0001), and a higher frequency of nonwhite race (P = .006) were significantly related to the t(1;19). Both the t(1;19) and other chromosomal translocations were associated with an adverse prognosis in the subset of patients treated from 1979 to 1984 (Total Therapy study X). In a more recent and more intensive chemotherapy program (Total Therapy study XI), neither the t(1;19) nor other chromosomal translocations has conferred an inferior outcome, suggesting that effective treatment can offset the negative impact of chromosomal rearrangements in cases of childhood pre-B ALL.
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