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671.
672.
Blocked negative selection of developing T cells in mice expressing the baculovirus p35 caspase inhibitor. 总被引:4,自引:2,他引:2
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M Izquierdo A Grandien L M Criado S Robles E Leonardo J P Albar G G de Buitrago C Martínez-A 《The EMBO journal》1999,18(1):156-166
Clonal deletion in the thymus by apoptosis is involved in purging the immune system of self-reactive T lymphocytes (negative selection). Cysteine proteases (caspases) belonging to the CPP32 family are activated during this process. We have produced transgenic mice expressing baculovirus p35, a broad-range caspase inhibitor. Thymocytes from p35 transgenic mice were resistant in vitro to several apoptosis-inducing agents; this resistance correlated with the inhibition of CPP32-like activity. Negative selection in vivo of thymocytes triggered by two exogenous antigens, staphylococcal enterotoxin B superantigen and an antigenic peptide in the F5 T-cell receptor transgenic model, was specifically inhibited in p35 transgenic mice. Our results provide direct evidence for caspase involvement in negative selection during thymocyte development. 相似文献
673.
Marc Beyer Hongwei Wang Nina Peters Sandra Doths Cordula Koerner-Rettberg Peter JM Openshaw Jürgen Schwarze 《Respiratory research》2005,6(1):70
Background
The integrin CD11c is known as a marker for dendritic cells and has recently been described on T cells following lymphotropic choriomeningitis virus infection, a systemic infection affecting a multitude of organs. Here, we characterise CD11c bearing T cells in a murine model of localised pulmonary infection with respiratory syncytial virus (RSV).Methods
Mice were infected intranasally with RSV and expression of β2 integrins and T lymphocyte activation markers were monitored by flow cytometry. On day 8 post RSV infection CD11c+ CD8+ and CD11c- CD8+ T cells were assessed for cytokine production, cytotoxic activity and migration. Expression of CD11c mRNA in CD8+ T cells was assessed by quantitative PCR.Results
Following RSV infection CD11c+ CD8+ T cells were detectable in the lung from day 4 onwards and accounted for 45.9 ± 4.8% of CD8+ T cells on day 8 post infection, while only few such cells were present in mediastinal lymph nodes, spleen and blood. While CD11c was virtually absent from CD8+ T cells in the absence of RSV infection, its mRNA was expressed in CD8+ T cells of both naïve and RSV infected mice. CD11c+, but not CD11c-, CD8+ T cells showed signs of recent activation, including up-regulation of CD11a and expression of CD11b and CD69 and were recruited preferentially to the lung. In addition, CD11c+ CD8+ T cells were the major subset responsible for IFNγ production, induction of target cell apoptosis in vitro and reduction of viral titres in vivo.Conclusion
CD11c is a useful marker for detection and isolation of pulmonary antiviral cytotoxic T cells following RSV infection. It identifies a subset of activated, virus-specific, cytotoxic T cells that exhibit potent antiviral effects in vivo. 相似文献674.
Mogas T Fernández-Novell JM Palomo MJ Otaegui PJ Gomis RR Ballester J Izquierdo D Guinovart JJ Ferrer JC Rigau T Rodríguez-Gil JE 《Biochemical and biophysical research communications》2002,297(4):841-846
Intra-testicular inoculation of an adenoviral vector carrying the fusion gene Aequorea victoria green fluorescence protein/rat-liver glycogen synthase (GFP/LGS) resulted in the presence of GFP/GLS in spermatozoa from 7days to, at least, 16days after inoculation. The GFP/LGS was detected in the sperm heads after an "in vitro" fertilization procedure, either before or after the oocyte penetration. Our results indicate that spermatozoa carrying GFP/LGS protein conserved their fertilizing ability and were also detectable after oocyte penetration. This technique will allow to develop an easy system to follow the fate of mature sperm proteins. 相似文献
675.
Szapiro G Galante JM Barros DM Levi de Stein M Vianna MR Izquierdo LA Izquierdo I Medina JH 《Neurochemical research》2002,27(11):1491-1498
Memory retrieval is a fundamental component or stage of memory processing. In fact, retrieval is the only possible measure of memory. The ability to recall past events is a major determinant of survival strategies in all species and is of paramount importance in determining our uniqueness as individuals. Most biological studies of memory using brain lesion and/or gene manipulation techniques cannot distinguish between effects on the molecular mechanisms of the encoding or consolidation of memories and those responsible for their retrieval from storage. Here we examine recent findings indicating the major molecular steps involved in memory retrieval in selected brain regions of the mammalian brain. Together the findings strongly suggest that memory formation and retrieval may share some molecular mechanisms in the hippocampus and that retrieval initiates extinction requiring activation of several signaling cascades and protein synthesis. 相似文献
676.
677.
Developmental competence of prepubertal goat oocytes selected with brilliant cresyl blue and matured with cysteamine supplementation 总被引:4,自引:0,他引:4
Rodríguez-González E López-Bejar M Izquierdo D Paramio MT 《Reproduction, nutrition, development》2003,43(2):179-187
The aim of this study was to assess the effect of oocyte selection using the brilliant cresyl blue (BCB) test plus the addition of cysteamine to the in vitro maturation (IVM) medium to improve the in vitro embryo development of prepubertal goat oocytes. The oocytes were exposed to 26 microM BCB and classified according to their cytoplasm coloration: BCB+ (oocytes with blue cytoplasm) and BCB- (unstained oocytes). The oocytes were matured in a conventional IVM medium supplemented with cysteamine 100 microM. The control group consisted of oocytes not exposed to BCB and matured without cysteamine. The IVM-oocytes were inseminated and cultured in synthetic oviductal fluid (SOF) for 7 days. The normal fertilisation rate (oocytes showing 2 pronuclei and 1 sperm tail) of BCB+ oocytes (40%) was higher than those of BCB- (21%) and control oocytes (22%). The percentage of morulae plus blastocysts was higher (P < 0.05) in the BCB+ group than in the BCB- group (23.8 vs. 5.1%, respectively). In conclusion, the integration of the BCB test and the addition of cysteamine in the protocol of in vitro embryo production from prepubertal goat oocytes has improved the developmental rates of embryo development. 相似文献
678.
Kraemer WJ Koziris LP Ratamess NA Hakkinen K TRIPLETT-McBRIDE NT Fry AC Gordon SE Volek JS French DN Rubin MR Gomez AL Sharman MJ Michael Lynch J Izquierdo M Newton RU Fleck SJ 《Journal of strength and conditioning research / National Strength & Conditioning Association》2002,16(3):373-382
The object of this study was to examine changes in muscular strength, power, and resting hormonal concentrations during 6 weeks of detraining (DTR) in recreationally strength-trained men. Each subject was randomly assigned to either a DTR (n = 9) or resistance training (RT; n = 7) group after being matched for strength, body size, and training experience. Muscular strength and power testing, anthropometry, and blood sampling were performed before the experimental period (T1), after 3 weeks (T2), and after the 6-week experimental period (T3). One-repetition maximum (1RM) shoulder and bench press increased in RT at T3 (p = 0.05), whereas no significant changes were observed in DTR. Peak power output and mean power output significantly decreased (9 and 10%) in DTR at T2. Peak torque of the elbow flexors at 90 degrees did not change in the RT group but did significantly decrease by 11.9% at T3 compared with T1 in the DTR group. Vertical jump height increased in RT at T2 but did not change in DTR. Neither group displayed any changes in 1RM squat, body mass, percent body fat, or resting concentrations of growth hormone, follicle-stimulating hormone, luteinizing hormone, sex hormone-binding globulin, testosterone, cortisol, or adrenocorticotropin. These data demonstrate that 6 weeks of resistance DTR in recreationally trained men affects power more than it does strength without any accompanying changes in resting hormonal concentrations. For the recreational weight trainer, losses in strength over 6 weeks are less of a concern compared with anaerobic power and upper arm isometric force production. Anaerobic power exercise with a high metabolic component coming from glycolysis might be of importance for reducing the impact of DTR on Wingate power performances. A minimal maintenance training program is recommended for the recreational lifter to offset any reductions in performance. 相似文献
679.
Structure-Related Oxidative Damage in Rat Brain After Acute and Chronic Electroshock 总被引:2,自引:0,他引:2
Barichello T Bonatto F Agostinho FR Reinke A Moreira JC Dal-Pizzol F Izquierdo I Quevedo J 《Neurochemical research》2004,29(9):1749-1753
The role of oxidative stress in electroconvulsive therapy-related effects is not well studied. The purpose of this study was to determine oxidative stress parameters in several brain structures after a single electroconvulsive seizure or multiple electroconvulsive seizures. Rats were given either a single electroconvulsive shock or a series of eight electroconvulsive shocks. Brain regions were isolated, and levels of oxidative stress in the brain tissue (cortex, hippocampus, striatum and cerebellum) were measured. We demonstrated a decrease in lipid peroxidation and protein carbonyls in the hippocampus, cerebellum, and striatum several times after a single electroconvulsive shock or multiple electroconvulsive shocks. In contrast, lipid peroxidation increases both after a single electroconvulsive shock or multiple electroconvulsive shocks in cortex. In conclusion, we demonstrate an increase in oxidative damage in cortex, in contrast to a reduction of oxidative damage in hippocampus, striatum, and cerebellum. 相似文献
680.
Rücker B Pereira GS Fürstenau CR Izquierdo I Bonan CD Sarkis JJ 《Neurochemical research》2004,29(12):2231-2237
Studies demonstrated that endogenous levels of estrogen affect the long-term potentiation (LTP) and long-term depression (LTD). ATP and adenosine may play a role in the modulation of LTP. Our laboratory observed in previous studies that inhibitory avoidance task is associated with a decrease in hippocampal ectonucleotidase activities in adult male rats. To explore if ectonucleotidases are modulated in memory formation in female rats, as observed in males, we evaluated the effect of inhibitory avoidance training on synaptosomal NTP Dase and 5-nucleotidase activities in rat hippocampus from both sexes. The results demonstrated a decrease in ATP, ADP and AMP hydrolysis (37%, 38% and 32%, respectively) immediately after training and a significant inhibition only in ATP hydrolysis (36%) 30 min post-training in male rats. There were no changes in ectonucleotidase activities from female rats. These findings provide support for the view that could exist biochemical differences in ectonucleotidase activities between males and females. 相似文献