Habituation of the hypothalamic-pituitary-adrenal (HPA) response to chronic intermittent restraint stress (30 min/day for 15 days) and the cross-sensitization to a heterotypic stress [i.p. lipopolysaccharide (LPS)] were investigated in intact male Sprague Dawley rats, and in rats bearing quinolinic acid lesions to the medial anterior bed nuclei of the stria terminalis (BST) or anterior region of the paraventricular nucleus of the thalamus (PVT). In intact animals, a single period of restraint increased plasma corticosterone levels at 30 min and led to an increase in corticotropin-releasing hormone (CRH) mRNA levels in the PVN at 3 h. LPS had a smaller effect on corticosterone and more variable effect on CRH mRNA. Chronic intermittent restraint stress caused a decrease in body weight and increase in adrenal weights, with concomitant increase in basal corticosterone levels. These animals also displayed marked habituation of the corticosterone and CRH mRNA responses to the homotypic stress of restraint, but no loss of the corticosterone response to the heterotypic stress of LPS and a cross-sensitization of the CRH mRNA response. This pattern of stress responses in control and chronically stressed animals was not significantly affected by lesions to the PVT or BST, two areas which have been implicated in the coping response to stress. Thus, these data provide evidence for independent adaptive mechanisms regulating HPA responses to psychological and immune stressors, but suggest that neither the medial anterior BST nor the anterior PVT participate in the mechanisms of habituation or cross-sensitization.
Geosynthetics have been used as reinforcement in various applications in geotechnical engineering. This paper presents a study on the use of geosynthetic reinforcement to reduce the consumption of good-quality sub-ballast material in a railway track in the state of Minas Gerais, Brazil. Six test sections on the railway were instrumented and monitored for a period of 2 years. Nonwoven geotextile and a geogrid were used as reinforcement in different positions in the subballast. The results obtained showed that the presence of geosynthetic reinforcement reduced the strains mobilised in the sub-ballast, reduced the breakage of ballast element, and allowed the use of a cheaper alternative material in the sub-ballast construction. The results showed the potential of the use of alternative sub-ballast material reinforced with geosynthetic to reduce the costs of construction and maintenance of railway tracks.
We studied the serum levels of IL-2, IFN-gamma and TNF in different clinical forms of Chagas' disease and in patients clinically compensated and decompensated. Cytokines measured in 91 patients with the chronic form of the disease did not differ from those of 13 normal individuals, suggesting the absence of activation of the TH1 pattern of lymphocyte response. There were no statistical differences among the 17 patients in the indeterminate form of the disease, the patients presenting either early (n = 4) or well-developed signs of cardiomyopathy (n = 62), the digestive (n = 4) or the mixed (n = 4) forms of the disease. Serum TNF was undetectable and IFN-gamma levels did not differ between clinical forms and severities of Chagas' disease. However, we found IL-2 higher levels in the 25 non-controlled patients than in the 66 controlled individuals (p < 0.001). We suggest that IL-2 dosage may be useful as an indicator of the need for more aggressive procedures.
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