Carcinogenesis concerns several changes that eventually result in the inactivation of tumor suppressor genes and activation of protooncogenes, leading to loss of cell cycle control. Inactivation of p16 seems to be an early event in this process and occurs in approximately 80% of squamous cell carcinoma cases. The aims of this study were to evaluate the immunohistochemical expression of p16 protein in oral and oropharyngeal squamous cell carcinoma cases, with both the tumoral area itself and its surgical margin being analyzed (dysplastic areas and histologically normal epithelium adjacent to carcinoma), and to verify the presence of human papillomavirus (HPV) and its relation to p16 expression. Paraffin-embedded biopsy tissues from 26 patients, 13 with oral squamous cell carcinoma and 13 with oropharyngeal squamous cell carcinoma, comprised the analyzed samples. To detect HPV, a nested polymerase chain reaction test using PGMY 09/11 and GP5*/GP6* primers and visualization of the product on a 2% agarose gel was performed. Demographic data were obtained from medical records. The results showed low expression of p16 in the tumor area (38.46%), compared with surgical margins in the histologically normal epithelium (84.6%) and dysplastic areas (57.7%). These findings indicate the inactivation of p16 in the process of malignant transformation. The association described in the literature between expression of p16 and presence of HPV could not be verified in this study, because none of the cases was HPV positive.
Endothelin (ET) and its precursor big-ET were synchronously analyzed by RIA in liver biopsies and systemic plasma during porcine orthotopic liver transplantation (OLT) before graft harvesting (phase A), after cold storage (phase B), and early (phase C) and late reperfusion (phase D). Tissue and plasma concentrations were correlated with length of survival and reperfusion. Increased tissue ET/big-ET levels were already detected during phase B (ET: 46 ± 20; big-ET: 245 ± 119 pg/mg cytosolic protein) and remained elevated in phase C (ET: 49 ± 16; big-ET: 306 ± 144 pg/mg) compared to baseline (ET: 32 ± 13; big-ET: 185 ± 164 pg/mg; p < 0.05). In phase D, a rapid concentration decline was detected (ET: 36 ± 26; big-ET: 163 ± 138 pg/mg). Systemic ET levels were elevated in phase B (3.4 ± 3.0 pg/ml), C, (2.8 ± 1.2 pg/ml) and D (2.6 ± 2.0 pg/ml), compared to baseline (1.7 ± 1.1 pg/ml; p < 0.05). ET/big-ET kinetics in liver tissue and systemic plasma showed analogous characteristics. Intrahepatic ET accumulation during storage and early reperfusion could be of relevance for harvest-related disturbances of hepatic microcirculation.
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