Influence of growth factors erythropoietin and granulocyte macrophage colony stimulating factor on mechanical strength and healing of colonic anastomoses in rats.

OBJECTIVE: To find out what influence erythropoietin and granulocyte macrophage colony stimulating factor (GM-CSF) had on the healing of left colonic anastomoses in rats. DESIGN: Experimental study. SETTING: University hospital of Ioannina, Greece. ANIMALS: 40 rats. INTERVENTIONS: An end to end anastomosis was created in the left colon. The rats in the experimental groups were treated with erythropoietin, or GM-CSF, or the two in combination. MAIN OUTCOME MEASURES: Tensile breaking strength of the anastomosis, histological characteristics of the anastomosed segment, changes in body weight, and packed cell volume (PCV) during the experiment. RESULTS: The tensile breaking strength of the anastomosis on the seventh postoperative day was significantly greater in the erythropoietin group (mean 2.8N, 95% confidence interval (CI) 0.12N, p 0.0004) than in the control group (mean 1.60N, 95% CI 0.12N). It did not differ from the GM-CSF groups (mean 1.67N, 95% CI 0.21N, p 0.68) or erythropoietin GM-CSF (mean 1.67N, 95% CI 0.11N, p 0.44). The PCV was significantly higher in the two groups given erythropoietin (p < 0.001) but not in the GM-CSF group (p 0.8) while that in the control group was significantly lower (p < 0.001). The body weight followed the same pattern, being significantly more in the two groups given erythropoietin (p = 0.03 and 0.003) but not in controls (p = 0.09) or the GM-CSF group (p = 0.2). CONCLUSIONS: Erythropoietin enhances the healing of anastomosis in rat colon by increasing the number of fibroblasts and accelerating the maturation of new vessels.

Immunohistochemical detection of ras P21 oncoprotein in human skin lesions.

This study was undertaken to investigate the role of the human ras family gene product [P21] in various benign, precancerous and malignant skin lesions. A streptavidin-biotin peroxidase method was performed using the monoclonal antibody (Mab)Y13259 in paraffin tissue sections of a total of 69 skin lesions (5 benign hyperplasias, 12 seborrheic keratoses, 9 solar keratoses, 20 basal cell carcinomas and 23 squamous cell carcinomas). The adjacent normal skin was also studied in all cases. The expression of ras P21 was evaluated and graded in relation to the intensity of cytoplasmic immunostaining and the percentage proportion of positive epidermal cells. The following findings were noted in this study: 1) The positivity of ras P21 increased towards the keratin layer, according to cell maturation, in all normal, hyperplastic and "borderline" lesions, and to a lower degree in the seborrheic ones. 2) Comparing B.C.C. and S.C.C., higher expression was demonstrated in the latter, probably due to the high percentage of the well differentiated component.