Biomedical subjects

Aina V H Greig

Publications and source records attributed to Aina V H Greig.

4 recordsLinked to original sources

PubMed2003

Purinergic receptors are part of a functional signaling system for proliferation and differentiation of human epidermal keratinocytes.

We investigated the expression of P2X5, P2X7, P2Y1 and P2Y2 receptor subtypes in normal human epidermis and in relation to markers of proliferation (PCNA and Ki-67), keratinocyte differentiation (cytokeratin K10 and involucrin) and markers of apoptosis (TUNEL and anticaspase-3). Using immunohistochemistry, we showed that each of the four receptors was expressed in a spatially distinct zone of the epidermis, suggesting different functional roles for these receptors. Functional studies were performed on primary cultures of human keratinocytes and on explanted rat skin, where different P2 receptor subtype agonists and antagonists were applied to cultured keratinocytes or injected subcutaneously into the skin, respectively. An increase in cell number was caused by low doses of the nonspecific P2 receptor agonist ATP, the P2Y2 receptor agonist UTP (p<0.001), and the P2Y1 receptor agonist 2MeSADP (p<0.05). There was a significant decrease in cell number as a result of treatment with the P2X5 receptor agonist ATPgammaS (p<0.001) and the P2X7 receptor agonist BzATP (p<0.001). Suramin caused a significant block in the effect of 100 microm ATP (p<0.01) and 1000 microm ATP (p<0.001) on cell number. These results imply that different purinergic receptors have different functional roles in the human epidermis with P2Y1 and P2Y2 receptors controlling proliferation, while P2X5 and P2X7 receptors control early differentiation, terminal differentiation and death of keratinocytes, respectively.

Animals↗

PubMed2003

Expression of purinergic receptors in non-melanoma skin cancers and their functional roles in A431 cells.

We investigated the use of purinergic receptors as a new treatment modality for nonmelanoma skin cancers. Purinergic receptors, which bind adenosine 5'-tri-phosphate, are expressed on human cutaneous keratinocytes. Previous work in rat and human epidermis suggested functional roles for purinergic receptors in the regulation of proliferation, differentiation, and apoptosis. Immunohistochemical analysis of frozen sections in human basal cell carcinomas and squamous cell carcinomas for P2X5, P2X7, P2Y1, P2Y2, and P2Y4 receptors was performed, accompanied by detailed analysis of archive material of tumor subtypes in paraffin sections. Functional studies were performed using a human cutaneous squamous cell carcinoma cell line (A431), where purinergic receptor subtype agonists were applied to cells and changes in cell number were quantified via a colorimetric assay. Immunostaining in paraffin sections was essentially the same as that in frozen sections, although more detail of the subcellular composition was visible. P2X5 and P2Y2 receptors were heavily expressed in basal cell carcinomas and squamous cell carcinomas. P2X7 receptors were expressed in the necrotic center of nodular basal cell carcinomas and in apoptotic cells in superficial multifocal and infiltrative basal cell carcinomas, and squamous cell carcinomas. P2Y1 receptors were only expressed in the stroma surrounding tumors. P2Y4 receptors were found in basal cell carcinomas but not in squamous cell carcinomas. P2X5 receptors appear to be associated with differentiation. The P2X7 receptor agonist benzoylbenzoyl-adenosine 5'-triphosphate and high concentrations of adenosine 5'-triphosphate (1000-5000 microM) caused a significant reduction in A431 cell number (p<0.001), whereas the P2Y2 receptor agonist uridine 5'-triphosphate caused a significant amount of proliferation (p<0.001). We have demonstrated that non-melanoma skin cancers express functional purinergic receptors and that P2X7 receptor agonists significantly reduce cell numbers in vitro.

Aged↗

PubMed2002

Leechcraft.

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Animals↗

PubMedDate not supplied

A study of perceptions of facial hemangiomas in professionals involved in child abuse surveillance.

Facial hemangiomas are common benign tumors of infancy. They can mimic the appearance of bruises and parents report false accusations of child abuse by strangers. We investigated perceptions of facial hemangiomas in two professional groups involved in child abuse surveillance. Thirty health visitors and 30 primary school teachers were sent a clinical case questionnaire about a child with an involuting facial hemangioma with a color photograph of the lesion. Nineteen health visitors (63%) and 18 primary school teachers (60%) responded. Seventy-four percent of the health visitors and 11% of the teachers correctly diagnosed a hemangioma. Fifty percent of the teachers were unable to decide on a diagnosis. However, only one health visitor (5%) and one teacher (5%) thought that the lesion was a nonaccidental injury and would involve a child protection advisor. About one-third of health visitors and one-third of teachers expressed concerns that the child could suffer psychologically from teasing by peers at school and about one-third of health visitors were also concerned about the psychological effects of the lesion on the child's parents. Health visitors and teachers were most unlikely to mistake the facial hemangioma in this study for a nonaccidental injury.

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