The Journal of pathology
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The Journal of pathology · Jul 2004
Possible linkage between specific histological structures and aberrant reactivation of the Wnt pathway in adamantinomatous craniopharyngioma.
This study concerns the significance of nuclear/cytoplasmic expression of beta-catenin and mutation of the beta-catenin gene in craniopharyngiomas. Fourteen adamantinomatous type and one squamous papillary type craniopharyngiomas were studied. Histologically, 13 of 14 adamantinomatous type craniopharyngiomas showed typical features, ie mixtures of 'palisading cells', 'stellate cells', and 'ghost cells'. ⋯ Using direct sequencing of amplified nucleic acids, nine of the 13 typical adamantinomatous type craniopharyngiomas with nuclear beta-catenin accumulation showed heterozygous one-base substitution mutation of the beta-catenin gene. The other unusual adamantinomatous type and squamous papillary type craniopharyngiomas showed no obvious nuclear/cytoplasmic beta-catenin immunoreactivity and no mutation of the beta-catenin gene, suggesting molecular heterogeneity. These findings suggest that the pathogenesis of typical adamantinomatous type craniopharyngioma is associated with abnormalities of Wnt signalling that act as a morphogenetic signal towards whorl-like arrays and ghost cells rather than as simple proliferation stimuli.
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The Journal of pathology · Jun 2004
Organ distribution of severe acute respiratory syndrome (SARS) associated coronavirus (SARS-CoV) in SARS patients: implications for pathogenesis and virus transmission pathways.
We previously identified the major pathological changes in the respiratory and immune systems of patients who died of severe acute respiratory syndrome (SARS) but gained little information on the organ distribution of SARS-associated coronavirus (SARS-CoV). In the present study, we used a murine monoclonal antibody specific for SARS-CoV nucleoprotein, and probes specific for a SARS-CoV RNA polymerase gene fragment, for immunohistochemistry and in situ hybridization, respectively, to detect SARS-CoV systematically in tissues from patients who died of SARS. SARS-CoV was found in lung, trachea/bronchus, stomach, small intestine, distal convoluted renal tubule, sweat gland, parathyroid, pituitary, pancreas, adrenal gland, liver and cerebrum, but was not detected in oesophagus, spleen, lymph node, bone marrow, heart, aorta, cerebellum, thyroid, testis, ovary, uterus or muscle. ⋯ In addition to viral spread through a respiratory route, SARS-CoV in the intestinal tract, kidney and sweat glands may be excreted via faeces, urine and sweat, thereby leading to virus transmission. This study provides important information for understanding the pathogenesis of SARS-CoV infection and sheds light on possible virus transmission pathways. This data will be useful for designing new strategies for prevention and treatment of SARS.
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The Journal of pathology · Apr 2004
Gene expression profiles from hypertrophic scar fibroblasts before and after IL-6 stimulation.
The structural rearrangement of collagen fibres in hypertrophic scar causes abnormal contracture, low tensile strength, and raised scars, which cause functional impairment and disfigurement. It is hypothesized that changes in the genes of cytokines, extracellular matrix proteins, and proteins regulating programmed cell death are related to hypertrophic scar formation. To test this hypothesis, fibroblasts were cultured from hypertrophic scars and their response to interleukin-6 (IL-6) stimulation was studied by defining their gene expression profiles. ⋯ Values are means +/- SEM. The absence of any up-regulation of MMP-1 and MMP-3 in hypertrophic scar fibroblasts, in response to IL-6, suggests that suppression of matrix metalloproteinases may play a role in the excessive accumulation of collagen formed in hypertrophic scars. While the pathogenesis of abnormal hypertrophic scars remains poorly understood, the use of gene expression arrays may prove helpful in identifying the mechanisms responsible for this type of abnormal scar formation and in formulating an effective therapeutic protocol.
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The Journal of pathology · Apr 2004
Gastrointestinal stromal tumours (GISTs) negative for KIT (CD117 antigen) immunoreactivity.
Gastrointestinal stromal tumours (GISTs) are currently defined as mesenchymal tumours of the gastrointestinal tract that express KIT receptor tyrosine kinase. However, a small subgroup of tumours that fulfil the clinical and morphological criteria for GISTs lack KIT expression. So far, the biological features of these tumours have rarely been addressed. ⋯ None of these three tumours expressed KIT, while all specimens showed expression of PKC theta protein. These findings indicate that there is a subgroup of KIT-negative GISTs that exhibit the same morphological, cytogenetic, and molecular features as KIT-positive tumours. While intragenic PDGFRA activating mutations are present in some of these tumours, the oncogenic events underlying the pathogenesis of the others remain unknown.
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The Journal of pathology · Feb 2004
ReviewRole of inflammatory mediators in the pathophysiology of acute respiratory distress syndrome.
Inflammatory response leading to organ dysfunction and failure continues to be the major problem after injury in many clinical conditions such as sepsis, severe burns, acute pancreatitis, haemorrhagic shock, and trauma. In general terms, systemic inflammatory response syndrome (SIRS) is an entirely normal response to injury. Systemic leukocyte activation, however, is a direct consequence of a SIRS and if excessive, can lead to distant organ damage and multiple organ dysfunction syndrome (MODS). ⋯ Inflammatory mediators play a key role in the pathogenesis of ARDS, which is the primary cause of death in these conditions. This review summarizes recent studies that demonstrate the critical role played by inflammatory mediators such as tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, platelet activating factor (PAF), IL-10, granulocyte macrophage-colony stimulating factor (GM-CSF), C5a, intercellular adhesion molecule (ICAM)-1, substance P, chemokines, VEGF, IGF-I, KGF, reactive oxygen species (ROS), and reactive nitrogen species (RNS) in the pathogenesis of ARDS. It is reasonable to speculate that elucidation of the key mediators in ARDS coupled with the discovery of specific inhibitors would make it possible to develop clinically effective anti-inflammatory therapy.