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Extracellular matrix of small round cell tumors of childhood: an immunohistochemical study of 67 cases
No full textSixty-seven childhood tumors were studied immunohistochemically for the extracellular matrix element type IV collagen, laminin, and fibronectin. Tumors included Ewing's sarcoma, primitive neuroectodermal tumor, small cell osteosarcoma, neuroblastoma or ganglioneuroblastoma, rhabdomyosarcoma, and lymphoma. It was found that small cell osteosarcoma was often positive for fibronectin but not type IV collagen or laminin, a new observation. In the lymphomas, matrix proteins were rarely found. Ewing's sarcoma was variably positive for type IV collagen and laminin, but fibronectin was absent. Extracellular laminin and fibronectin were found in one of two cases of primitive neuroectodermal tumor. In neuroblastoma and ganglioneuroblastoma, the matrix components were rarely found. These results, discrepant with findings in cultured cells, may reflect the altered capacity of tumors to produce these proteins in vitro, which suggests that caution should be exercised in drawing conclusions regarding the nature or histogenesis of tumors from data obtained with cultured tumor cells. Embryonal rhabdomyosarcoma frequently contained all matrix elements in the extracellular space and in a dotlike pattern in the cytoplasm; alveolar rhabdomyosarcoma rarely contained these proteins and never exhibited the dotlike pattern. The frequent finding of matrix proteins in embryonal rhabdomyosarcoma but only rarely in alveolar rhabdomyosarcoma and the unique immunostaining pattern in embryonal rhabdomyosarcoma may prove to be a useful adjunct in the diagnosis of childhood tumors
Leukemia and liver disease in chilhood: clinical and histological evaluation
No full textSeventy-two consecutive patients with acute lymphocytic leukemia (ALL) who had undergone liver biopsy within 3 months of completing chemotherapy were studied to evaluate histological features after 2 to 3 years of chemotherapy and to correlate liver disease to the treatment schedule, the number of transfused blood units, and the identified etiology. Fibrosis due to antiblastic drugs was the most frequent histological finding. Histological liver disease was not related either to the chemotherapy schedule or the number of transfused blood units. HBV with or without delta virus and HCV infections were related to a more severe histological liver disease. In about 40% patients with chronic liver disease, no etiology was demonstrated. Immunohistochemistry revealed HBcAg in the liver of 3 HBsAg-negative patients. In conclusion, liver biopsy could be useful in patients with persistent abnormal liver function tests after the completion of chemotherapy and in patients with markers for hepatotropic virus infectio
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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