Abstract Prostate cancer is the second most common cancer among men in western populations, and despite its high mortality, its etiology remains unknown. Inflammatory processes are related to the etiology of various types of tumors, and prostate inflammation, in particular, has been associated with prostate cancer carcinogenesis and progression. Human papillomavirus (HPV) is associated with benign and malignant lesions in the anogenital tract of both females and males. The possible role of HPV in prostate carcinogenesis is a subject of great controversy. In this study, we aimed to examine the prevalence of HPV infections in prostate carcinomas of patients from northeastern Brazil. This study included 104 tissue samples from primary prostate carcinoma cases. HPV DNA was purified and then amplified using MY09/11 and GP5+/GP6+ degenerate primer sets that detect a wide range of HPV types, and with specific PCR primers sets for E6 and E7 HPV regions to detect HPV 16. None of the samples showed amplification products of HPV DNA for primer sets MY09/11 and GP5+/GP6+, or the specific primer set for the E6 and E7 HPV regions. HPV infection, thus, does not seem to be one of the causes of prostate cancer in the population studied.

Two nondestructive methods for estimating the individual leaf area (AFi) of two sweet sorghum hybrids [Sorghum bicolor (L.) Moench] were studied. Samples of 435 and 497 leaf blades of Argensil 165 Bio and Padrillo, respectively, were extracted in successive phenological stages. In each leaf blade, length and maximum width were measured and leaf area pattern (AFP) was determined. AFP data in function of length (method 1) and length by maximum width of leaf blade (method 2) were analyzed by regression analysis to determine the best adjusted equations. Results indicated that for Padrillo, the model for method 1 was AFi= 0.260*length 1.661 (R²= 0.905), and for method 2, AFi= 0.722* (length x maximum width) (R²= 0.986). In the case of Argensil 165 Bio, the function for method 1 was AFi= 0.205* length 1.743 (R²= 0.927), whereas for method 2 it was AFi= 0.737* (length x maximum width) (R²= 0.983). For both hybrids, method 2 was the most precise and the slope comparison test indicated that it is necessary to use the specific models for each hybrid.

Se estudiaron dos métodos no destructivos de estimación del área de hojas individuales (AFi) en dos híbridos de sorgo azucarado [Sorghum bicolor (L.) Moench]. Se trabajó con muestras de 435 y 497 láminas foliares de Argensil 165 Bio y Padrillo, respectivamente, extraídas en sucesivos estadios fenológicos. En cada lámina, se midieron el largo y el ancho máximo y, además, se determinó el área foliar patrón (AFP). Los datos del AFP en función del largo (método 1) y del largo por el ancho máximo de la lámina (método 2) se sometieron a un análisis de regresión para determinar las ecuaciones de mejor ajuste. Los resultados indicaron que en Padrillo, el modelo para el método 1 fue AFi = 0,260*largo1,661(R²: 0,905) y para el método 2 fue AFi = 0,722 *(largo x ancho máximo) (R²=0,986). En Argensil 165 Bio, la función para el método 1 fue AFi = 0,205*largo1,743 (R²: 0,927) y, para el método 2, AFi = 0,7370*(largo x ancho máximo) (R²=0,983). En ambos híbridos, el método 2 otorgó la mayor precisión y el test de comparación de las pendientes indicó que debe emplearse el modelo específico para cada híbrido.

Aberrant methylation of CpG islands located in promoter regions represents one of the major mechanisms for silencing cancer-related genes in tumor cells. We determined the frequency of aberrant CpG island methylation for several tumor-associated genes: DAPK, MGMT, p14ARF, p16INK4a, TP73, RB1 and TIMP-3 in 55 brain tumors, consisting of 26 neuroepithelial tumors, 6 peripheral nerve tumors, 13 meningeal tumors and 10 metastatic brain tumors. Aberrant methylation of at least one of the seven genes studied was detected in 83.6% of the cases. The frequencies of aberrant methylation were: 40% for p14ARF, 38.2% for MGMT, 30.9% for, p16INK4a, 14.6% for TP73 and for TIMP-3, 12.7% for DAPK and 1.8% for RB1. These data suggest that the hypermethylation observed in the genes p14ARF, MGMT and p16INK4a is a very important event in the formation or progression of brain tumors, since the inactivation of these genes directly interferes with the cell cycle or DNA repair. The altered methylation rate of the other genes has already been reported to be related to tumorigenesis, but the low methylation rate of RB1 found in tumors in our sample is different from that so far reported in the literature, suggesting that perhaps hypermethylation of the promoter is not the main event in the inactivation of this gene. Our results suggest that hypermethylation of the promoter region is a very common event in nervous system tumors.