MR imaging is the single best technique in assessment of patients with suspected tibial stress injuries; in some patients with negative MR imaging findings, CT can depict osteopenia, which is the earliest finding of fatigue cortical bone injury.
The present study defines the location of the laminin alpha1 chain in involved and uninvolved psoriatic skin and suggests a possible role of the alteration of this chain, together with T-cell lymphokines and fibronectin, in the dysregulation of cell morphological processes.
Previous studies have demonstrated the presence in psoriatic lesions of ultrastructural and molecular alterations of the basement membrane and an altered polarized distribution of the integrins; this latter alteration has also been observed in uninvolved skin. The aim of the present study was to determine, by means of immunolocalization with monoclonal antibodies directed against laminin 1 and type IV collagen and using confocal scanning laser microscopy, whether there are also alterations of the main components of the basement membrane in uninvolved skin. The findings showed a discontinuous and fragmented staining of laminin 1 and a normal distribution of type IV collagen. Taking into account both these results and the results of studies on epithelial cell lines, the authors hypothesize the existence of a functional deficit in psoriatic keratinocytes affecting the synthesis of the alpha 1 subunit of laminin. This deficit would explain: (1) the incapacity to produce mature trimeric laminin; (2) the altered assembly into a distinct basal lamina; (3) the loss of keratinocyte adhesion to the basement membrane; (4) alterations in the polarized distribution of the integrins; and (5) the consequent total or partial block of the cell signals regulating the processes of cytomorphosis. Already present in uninvolved skin, and enhanced by various irritative stimuli, this situation could be decisive for the appearance of psoriatic lesions.
Psoriasis is a typical hyperproliferative epidermal disease whose aetiopathogenesis is still to be defined. One of the most likely hypotheses is that it has a neurogenic origin correlated with an altered release of some neuropeptides by sensitive cutaneous nerves via antidromic pathways. As there are conflicting reports about the existence of cutaneous nerve alterations in psoriasis, we carried out an immunolocalization study using the protein gene product 9.5 as a marker for neuronal structures observed by confocal laser scanning microscopy in order to determine the pattern of sensory nerves in psoriatic skin. The investigation was carried out on cutaneous biopsies taken from involved (mature and long-established lesions) and uninvolved skin of ten patients with extensive chronic plaque psoriasis. In uninvolved psoriatic skin a significant decrease in epidermal nerve fibres was found, a further decrease was observed in mature lesions and almost a complete lack of epidermal nerve fibres in long-established psoriatic lesions. The reduction in epidermal nerve fibres and the consequent loss of relationship between these nerve structures and the skin immunocompetent cells (antigen-presenting cells, Langerhans cells, keratinocytes) might be a factor of fundamental importance in the self-maintenance of the disease.
High-resolution CT has high diagnostic accuracy in depicting medial tibial stress syndrome. Cortical abnormalities can also be seen in some asymptomatic distance runners.
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