Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.3.1 (alkaline phosphatase)
 47,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Studies on the maturational lineages of thymic lymphocytes have revealed several subclasses which are distinguishable on the basis of cell size, topographic distribution within the thymus, DNA synthetic and mitotic activity, migratory behavior, and other properties. Strain C57BL/Ka mice were inoculated with radiation leukemia virus at different concentrations, and tissues were removed at defined intervals. Sequential sections were analyzed for virus-specific cytoplasmic antigen expression, for morphological evidence of neoplastic transformation, and for alkaline phosphatase activity. The first detectable sign of MuLV infection was the focal appearance of cytoplasmic viral antigens in cells of the outer thymic cortex, followed by coalescence of such foci and, several weeks later, by the appearance of morphologically transformed and alkaline phosphatase-positive cells, again often focally distributed in the outer thymic cortex. These observations strongly suggest that the large, mitotically active cells of the outer thymic cortex are the principal source of target cells for both productive infection and subsequent lymphoma induction by the virus.
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PMID:Focal infection and transformation in situ of thymus cell subclasses by a thymotropic murine leukemia virus. 17 27

Cytochemical methods at the light and electron microscopic level were used to define the pattern of alkaline phosphatase (APase) activity in normal thymus and to study its modifications after inoculation with the thymotropic leukemogenic radiation leukemia virus in correlation with the emergence of preleukemic cells and their thymus dependency. APase was found in numerous lymphoblasts of the fetal thymus. The enzyme was also detected in a few lymphoid blast cells of the normal young adult thymus, which were closely associated with thymic nurse cells. The observed distribution of APase in normal thymus suggests that its expression could be limited to an early stage of the T-cell differentiation pathway. After inoculation with radiation leukemia virus, APase activity remained normal for almost the entire latency period, during which virus replication spread to the cortex and thymus-dependent preleukemic cells appeared. An important increase in the number of APase-positive cells occurred later, i.e., at the end of the latency period, in nontumoral thymus, which displayed lymphocytic depletion and contained autonomous thymus-independent preleukemic cells. These latter features obviously reflected the malignant transformation of thymus lymphoblasts, which eventually led to the development of the thymic lymphomas. The results raise the question of the possible filiation between the thymic nurse cell-associated APase-positive lymphoid cells of the normal thymus and the target cells susceptible to productive infection and to neoplastic transformation after radiation leukemia virus infection.
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PMID:Correlation of alkaline phosphatase activity to normal T-cell differentiation and to radiation leukemia virus-induced preleukemic cells in the C57BL mouse thymus. 631 7