Behavioral dysfunction, brain oxidative stress, and impaired mitochondrial electron transfer in aging mice. Am J Physiol Regulatory Integrative Comp Physiol 282: R985-R992, 2002; 10.1152/ajpregu.00537.2001.-Behavioral tests, tightrope success, and exploratory activity in a T maze were conducted with male and female mice for 65 wk. Four groups were defined: the lower performance slow males and slow females and the higher performance fast males and fast females. Fast females showed the longest life span and the highest performance, and slow males showed the lowest performance and the shortest life span. Oxidative stress and mitochondrial electron transfer activities were determined in brain of young (28 wk), adult (52 wk), and old (72 wk) mice in a crosssectional study. Brain thiobarbituric acid reactive substances (TBARS) were increased by 50% in old mice and were ϳ15% higher in males than in females and in slow than in fast mice. Brain Cu,Zn-superoxide dismutase (SOD) activity was increased by 52% and Mn-SOD by 108% in old mice. The activities of mitochondrial enzymes NADH-cytochrome c reductase, cytochrome oxidase, and citrate synthase were decreased by 14-58% in old animals. The cumulative toxic effects of oxyradicals are considered the molecular mechanism of the behavioral deficits observed on aging. neuromuscular impairment; NADH-cytochrome c reductase BOTH AGING AND AGE-ASSOCIATED neurodegeneration are related to the development of behavioral impairments; consequently, decreased performances in neuromuscular coordination and exploratory tests are considered markers of neurological aging (15). The life span of rodent strains was found inversely related to the intensity of their behavioral and neuroendocrine responses to stress, this type of evidence suggesting a genetic linkage between the quality of response to stress, the performance in behavioral tests, the rate of age-dependent neurodegeneration, and life span (12,13,19).The likely molecular candidates responsible for the neuromuscular deficits are oxidizing free radicals and the consequent oxidative stress they generate. The free radical theory of aging, understood as the decline of biological function on time, is complemented with the concept that life span is a consequence of oxygen toxicity at 20 kPa O 2 (18, 21). When the free radical theory of aging (21) is focused in mitochondria, it becomes more attractive as the mitochondrial hypothesis of aging (22,30,37 • that act as intermediates and, among others, the stable products of the oxidation of unsaturated fatty acids, proteins, and DNA. Thiobarbituric acid reactive substances (TBARS), protein carbonyls, and 8-hydroxy-deoxyguanosine (8-OH-dG) are the usual markers of oxidative stress as byproducts of free radical-mediated oxidation of cell components. The first aim of this study, in accordance with the mitochondrial hypothesis of aging, was to assess oxidative stress and mitochondrial electron transfer in aging animals. The second aim was to establish the relationships between oxidative stress mar...

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BackgroundPleural fluid homocysteine (HCY) can be useful for diagnosis of malignant pleural effusion (MPE). There are no published studies comparing the diagnostic accuracy of HCY with other tumour markers in pleural fluid for diagnosis of MPE. The aim was to compare the accuracy of HCY with that of carcinoembryonic antigen (CEA), cancer antigen (CA) 15.3, CA19.9 and CA125 in pleural fluid and to develop a probabilistic model using these biomarkers to differentiate benign (BPE) from MPE.MethodsPatients with pleural effusion were randomly included. HCY, CEA, CA15.3, CEA19.9 and CA125 were quantified in pleural fluid. Patients were classified into two groups: MPE or BPE. By applying logistic regression analysis, a multivariate probabilistic model was developed using pleural fluid biomarkers. The diagnostic accuracy was determined by receiver operating characteristic (ROC) curves and calculating the area under the curve (AUC).ResultsPopulation of study comprised 133 patients (72 males and 61 females) aged between 1 and 96 years (median = 70 years), 81 BPE and 52 MPE. The logistic regression analysis included HCY (p<0.0001) and CEA (p = 0.0022) in the probabilistic model and excluded the other tumour markers. The probabilistic model was: HCY+CEA = Probability(%) = 100×(1+e-z)-1, where Z = 0.5471×[HCY]+0.3846×[CEA]–8.2671. The AUCs were 0.606, 0.703, 0.778, 0.800, 0.846 and 0.948 for CA125, CA19.9, CEA, CA15.3, HCY and HCY+CEA, respectively.ConclusionsPleural fluid HCY has higher accuracy for diagnosis of MPE than CEA, CA15.3, CA19.9 and CA125. The combination of HCY and CEA concentrations in pleural fluid significantly improves the diagnostic accuracy of the test.

T lymphocytes are key players in adaptive immune responses through the recognition of peptide antigens through the T Cell Receptor (TCR). After TCR engagement, a signaling cascade is activated, leading to T cell activation, proliferation, and differentiation into effector cells. Delicate control of activation signals coupled to the TCR is needed to avoid uncontrolled immune responses involving T cells. It has been previously shown that mice deficient in the expression of the adaptor NTAL (Non-T cell activation linker), a molecule structurally and evolutionarily related to the transmembrane adaptor LAT (Linker for the Activation of T cells), develop an autoimmune syndrome characterized by the presence of autoantibodies and enlarged spleens. In the present work we intended to deepen investigation into the negative regulatory functions of the NTAL adaptor in T cells and its potential relationship with autoimmune disorders. For this purpose, in this work we used Jurkat cells as a T cell model, and we lentivirally transfected them to express the NTAL adaptor in order to analyze the effect on intracellular signals associated with the TCR. In addition, we analyzed the expression of NTAL in primary CD4+ T cells from healthy donors and Rheumatoid Arthritis (RA) patients. Our results showed that NTAL expression in Jurkat cells decreased calcium fluxes and PLC-γ1 activation upon stimulation through the TCR complex. Moreover, we showed that NTAL was also expressed in activated human CD4+ T cells, and that the increase of its expression was reduced in CD4+ T cells from RA patients. Our results, together with previous reports, suggest a relevant role for the NTAL adaptor as a negative regulator of early intracellular TCR signaling, with a potential implication in RA.