{'fraction_non_alphanumeric': 0.03776223776223776, 'fraction_numerical': 0.011888111888111888, 'mean_word_length': 5.012605042016807, 'pattern_counts': {'":': 0, '<': 1, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
[Structural alterations of the smooth muscle and of the EGFR expression and C-kit in congenital pyeloureteral stenosis. Relationship with its pathogenesis].

PURPOSE
To assess the role that the muscular dysplasia, epidermal growth factor (EGFR) and interstitial cells of Cajal (ICC) C-kit +, may have in the pathophysiology of pyeloureteral stenosis (EPU).


MATERIALS AND METHODS
30 samples were studied UPJ (ureteropelvic junction), with 25 UPJ obstruction and 5 controls. Performed with Masson's trichrome staining and immunohistochemical techniques for smooth muscle actin, EGFR (epidermal growth factor) and CD117 (C-kit) (Dako). We compared the results statistically.


RESULTS
The control group was diffuse positivity of EGFR in the muscle layer in samples of EPU was positive in 4%, weak in 16% and negative in 80%. The controls are C-kit + ICC between the muscle cells showed a decreased density in the samples of obstruction. Masson's trichrome highlighted the increase of inter-and intramuscular collagen and attenuated muscle fibers, thinner and individualized, in the inner muscular layer of the cases of EPU also evident with the actin. Differences between groups were statistically significant (p < 0.001).


CONCLUSIONS
Our results suggest that dysplastic changes in the muscle layer, the low expression of EGFR and the decrease or absence of C-kit + ICC, may participate in the pathophysiology of UPJ obstruction.