These results suggest that chronic AT1 blockade with losartan decreases the post-transcriptional synthesis of fibril-forming collagen type I molecules in young SHR. This effect may be involved in the ability of this drug to reverse left ventricular fibrosis in young rats with genetic hypertension. Apart from its antihypertensive action, other mechanisms may mediate the antifibrotic effect of losartan in this animal model.

Bilateral ovariectomy or adrenalectomy are experimental tools used to understand the mechanisms regulating the hypothalamus-pituitary-ovarian and the hypothalamus-pituitary-adrenal axis. There is evidence that acute unilateral perforation of the dorsal peritoneum in rats results in significant changes in progesterone, testosterone and estradiol serum concentrations. Because different surgical approaches for unilateral or bilateral ovariectomy or adrenalectomy, sectioning the superior ovarian nerve or the vagus nerve are used, we compare the acute effects on hormone serum concentrations resulting from the unilateral or bilateral dorsal approach to performing bilateral ovariectomy or adrenalectomy with those obtained when an unilateral incision is performed in the ventral abdomen. In general, the progesterone, testosterone and estradiol serum concentrations were higher in animals with ventral approach than in those with dorsal surgery, the effects varying depending on the day of the estrous cycle when surgery was performed. The results suggest that the neural signals arising from different zones of the peritoneum and/or the abdominal wall play different roles in the mechanisms regulating steroid hormones concentrations.

Introduction: Rainfed agriculture is one of the most vulnerable forms of crop to the effects of climate change producing either drought or excess moisture and thus damaging crops and causing substantial economic damage. In developing countries with scarce resources for technological investment, rainfed agriculture is extremely important for the food production. The sowing of seasonal maize in the Bajo Balsas is for self-consumption, thence the importance of identifying climatic hazard indicators that threaten agricultural production of this culture. The purpose of this study was to build and validate climatic hazard indicators considering the different phenological stages of the plant.                       Method: First, we identify the climatic variables and characterize the phenological cycle of maize variety that is cultivated in the region; then we elaborate a database with the following daily and monthly climatic parameters: pluvial precipitation, maximum temperature and minimum temperature. We applied data mining with the WEKA software to validate and classify the maize production of 18 years, then, the years were classified by production defining three classes: 1) low hazard: a sinister area from 0 to 10%, without drought reports; 2) moderate hazard: a sinister area from 11 to 50%, with moderate drought reports; 3) high hazard: a sinister area from 51 to 100%, with reports of severe drought.                       Results: We determined ten climatic hazard indicators of which four correspond to the number of days with precipitation lower than zero in the months of June, July, August and September (DDE0jun, DDE0jul, DDE0aug, DDE0sep); two indicators with rainfall equal to 5 mm for June and August (DDL5jun, DDL5aug); two indicators associated with the maximum temperature of July and August (TX38jul, TX38aug), and two indicators with precipitation equal to or greater than 10 mm in October and November (WDH10oct, WDH10nov). The result of the Kappa statistic was 0.91, indicating a high reliability in the classification of three hazardness categories: high, moderate and low.                       Conclusion: The proposed method on the validation of climatic hazard with the WEKA software allowed to identify the most important indicators that affect the maize phenological cycle and therefore its yield; the mathematical validation of the method shows three primary indicators, which indicates that there are primary and secondary variables that determine its climatic hazard. The indicators of climatic hazard were automated and adjusted using ICC® (Indicators of Climatic Change) which offers a useful tool for future research on climate hazard analysis of other rainfed crops.