The American journal of pathology
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Hepatic ischemia-reperfusion (I/R) is characterized by circulatory and metabolic derangements, liver dysfunction, and tissue damage. However, little is known about the causative role of I/R-induced microcirculatory disturbance on the manifestation of postischemic reperfusion injury. Therefore, the intention of the study was to assess changes of hepatic microvascular perfusion (intravital fluorescence microscopy) as related to hepatic morphology (light/electron microscopy), hepatocellular integrity (serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) activities), and excretory function (bile flow). ⋯ Prolongation of lobar ischemia (group C, 60 minutes) aggravated postischemic reperfusion injury (sinusoidal perfusion rate: 87.4 +/- 2.9%; erythrocyte flux: 62.1 +/- 8.4%) and was paralleled by severed hepatocellular damage. Electron microscopy of postischemic tissue demonstrated alteration of nonparenchymal cells (swelling of sinusoidal lining cells and widening of Disse's space) and substantial parenchymal cell damage (swelling of mitochondria, disarrangement of rough endoplasmatic reticulum, vacuolization, complete cytoplasmic degeneration). Initial postischemic increase in serum AST and ALT activities and reduction of bile flow directly correlated with the extent of microcirculatory failure (P < 0.01), ie, impairment of sinusoidal perfusion and decrease of erythrocyte flux, indicating the decisive role of microvascular perfusion failure for the manifestation of hepatic tissue damage and liver dysfunction.
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Several recent reports have suggested that nodular lymphocyte predominance Hodgkin's disease (NLPHD) may be distinct from other forms of Hodgkin's disease and may be more closely related to B-cell non-Hodgkin's lymphoma. This is primarily based on immunophenotypic studies that have shown that the L & H cells in NLPHD demonstrate a B-cell phenotype. In 1989, Poppema reported that the T cells in NLPHD differ from T cells in other forms of Hodgkin's disease in that they demonstrate reactivity for Leu 7 (CD57). ⋯ While scattered Leu 7 (CD57)-reactive lymphocytes were found in the other disorders, the percentage of reactive cells and the pattern of reactivity were significantly different in NLPHD. These results suggest that Leu 7 (CD57) reactivity may be used as an additional immunophenotypic criterion in distinguishing NLPHD from nodular sclerosing Hodgkin's disease, T-cell-rich B-cell lymphoma, and follicular lymphoma. The clinical and biological significance of Leu 7 (CD57) reactivity of small lymphocytes in NLPHD merits further investigation.
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Thermal energy causes an immediate, irreversible injury at the burn site, followed by a delayed, reversible tissue loss in the area surrounding the burn site due to progressive ischemia. We investigated the role of lipid peroxidation in the pathogenesis of progressive ischemia in a rat burn model. The burn model consisted of a row of four 10 x 20 mm burns separated by three unburned 5 x 20 mm skin bridges (interspaces). ⋯ Four separate burn wounds healed between three viable strips of hair-bearing interspaces. The treatment was effective, when given systemically during the period between 2 hours before and 1 hour after the burn. U75412E prevented progressive burn ischemia and the expansion of tissue loss.
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The authors studied four chordomas with malignant spindle cell components (SCs) and 12 conventional chordomas (CCs) by DNA flow cytometry using paraffin-embedded tissue. In addition, immunohistochemical stains for a variety of epithelial and mesenchymal markers were performed. The four SCs contained areas histologically identical to conventional chordomas, as well as a high-grade malignant spindle cell component. ⋯ In two cases, the staining for EMA and cytokeratin highlighted a gradual transition between the areas of conventional chordoma and the spindle cell areas. The immunohistochemical staining pattern of the 12 conventional chordomas was similar to that seen in the conventional chordoma components of the four chordomas with malignant spindle cell components. These results suggest that: 1) aneuploidy is more common in SCs than in CCs, and 2) some SCs are multipotential neoplasms in which the neoplastic cells are capable of differentiation along both epithelial and mesenchymal pathways.
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Kaposi's sarcoma is a neoplasm that develops as multifocal lesions, often involving the skin, characterized by a complex histologic picture including numerous vascular spaces, perivascular and interstitial spindle-shaped cells, and extravasated erythrocytes, lymphocytes, and plasma cells. Using an antibody against factor XIIIa, which identifies dermal dendrocytes, numerous factor XIIIa-positive dermal dendrocytes were detected among the spindle-shaped cells in 12 acquired immune deficiency syndrome (AIDS)-associated, and five non-AIDS-associated Kaposi's sarcoma lesions. The factor XIIIa-positive dermal dendrocytes were also increased in histologic simulators of Kaposi's sarcoma such as dermatofibroma, angiomatoid malignant fibrous histiocytoma, granuloma annulare, and early wound healing, but were absent in keloids. ⋯ Apparently a diverse array of stimuli, including human immunodeficiency virus type-1 (HIV-1) infection and trauma, can stimulate the accumulation of factor XIIIa expressing dermal dendrocytes in the skin. These cells can then participate in different stages of a variety of cutaneous alterations including Kaposi's sarcoma, dermatofibroma, granuloma annulare, and early wound healing. Thus, the factor XIIIa-positive dermal dendrocyte is a common cellular denominator among diverse clinical entities that share some histologic features.