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11.
Expression in Escherichia coli of a dominant immunogen of Trypanosoma cruzi recognized by human chagasic sera. 下载免费PDF全文
P C Cotrim G S Paranhos R A Mortara J Wanderley A Rassi M E Camargo J F da Silveira 《Journal of clinical microbiology》1990,28(3):519-524
A genomic clone expressing a Trypanosoma cruzi antigen in Escherichia coli was identified using human chagasic sera. Chagasic antibodies affinity purified on extracts of this clone recognized a high-molecular-weight protein expressed in all developmental stages of the parasite life cycle, as well as in various T. cruzi strains. The antigen is associated with the cytoskeleton of the parasite and localizes along the attachment region between the flagellum and the cell body. Antibodies to the recombinant antigen were detected in the sera of 115 chagasic patients from different endemic regions, but not in sera of patients with leishmaniasis, T. rangeli infection, or other parasitic diseases. Our data suggest that the presence of antibodies to this antigen may be specifically associated with Chagas' disease. 相似文献
12.
Mylne Lesnchal Laurence Becquart Xavier Lacoux Laurent Ladavire Renata C. P. Baida Glaucia Paranhos-Baccal Jos Franco da Silveira 《Clinical and Vaccine Immunology : CVI》2005,12(2):329-333
Tc40 is an immunodominant antigen present in natural Trypanosoma cruzi infections. This immunogen was thoroughly mapped by using overlapping amino acid sequences identified by gene cloning and chemical peptide synthesis. To map continuous epitopes of the Tc40 antigen, an epitope expression library was constructed and screened with sera from human chagasic patients. A major, linear B-cell epitope spanning residues 403 to 426 (PAKAAAPPAA) was identified in the central domain of Tc40. A synthetic peptide spanning this region reacted strongly with 89.8% of the serum samples from T. cruzi-infected individuals. This indicates that the main antigenic site is defined by the linear sequence of the peptide rather than a conformation-dependent structure. The major B-cell epitope of Tc40 shares a high degree of sequence identity with T. cruzi ribosomal and RNA binding proteins, suggesting the existence of cross-reactivity among these molecules. 相似文献
13.
Andrade MM Tomé MF Santiago ES Lúcia-Santos A de Andrade TG 《Physiology & behavior》2003,78(1):125-133
We conducted a longitudinal study about daily variation of Wistar male rats' behavior in the elevated plus-maze (EPM) evaluated in the 1st, 2nd, 3rd, 6th, 12th, and 18th months of life. Animals were submitted to the plus-maze in 12 sessions at 2-h intervals (n=72, 6 per time point). Spontaneous rest-activity rhythm of four animals was assessed by observation of 24-h videotape records. Time series were analyzed by Cosinor method. Behavioral rates on the six occasions and in light and dark phases were compared by means of two-way ANOVA with repeated measures. Exploratory behavior in EPM was smaller in the light phase and in older animals. Higher values of open and closed arms exploration were observed in the first and third months of the dark phase, and in the first month of the light phase. Adjustment to the 24-h period was significant at all stages for rest-activity data, number of entries in closed arms, and time on center, and for three to five stages for open-arm exploration. In general, 24 h variability was more pronounced in younger animals compared with older ones. The present study showed that: (1). a significant amount of total variability of the behavioral indexes analyzed could be attributed to 24 h variation, (2). light/dark phases differences in EPM exploration were present at all developmental stages, (3). older Wistar rats explored less the EPM and were less active in their home cage compared with younger ones, and (4). behavioral indexes (EPM) decrease was phase related and partially related to a reorganization of rest-activity rhythm. 相似文献
14.
15.
Christophe Cornu Maria-Izabel Almeida Silveira F. Goubel 《European journal of applied physiology》1997,76(3):282-288
The objective of this work was to study the effects of plyometric training on the mechanical properties of the ankle joint
in humans. Changes in the mechanical parameters of this musculo-articular structure were quantified with the aid of a sinusoidal
perturbation technique. This technique allowed the expression of the mechanical impedance of the musculo-articular system
in terms of stiffness, viscosity and inertia. Measurements were performed under passive conditions and when the subject performed
plantar flexion. A 7-week period of training induced a decrease in the slope of the relationship between stiffness and plantar
flexion torque, whereas passive stiffness was increased. A slight decrease in viscosity and an invariability in inertia were
also found. These results are interpreted in terms of the possible adaptations of the musculo-articular structure and ultrastructure
involved in the performance of plantar flexion.
Accepted: 11 April 1997 相似文献
16.
The ganglion cell response to optic nerve injury in the cat: differential responses revealed by neurofibrillar staining 总被引:3,自引:0,他引:3
Summary The early responses of cat retinal ganglion cells to axotomy have been examined using neurofibrillar and Nissl-stained wholemounts. We were interested to learn whether the enhanced neurofilament expression, seen in a number of neuronal systems, was also present in different neuronal populations of the cat retina and could be used to study the distribution of these cells. We found that beta ganglion cells degenerate very rapidly after axotomy with the nuclei becoming pyknotic within a few days. Few beta cells showed increased neurofibrillar staining of the dendrites. The cell body degenerated prior to any visible degenerative changes in the axon. A proportion of the alpha and gamma ganglion cells degenerated in the first two to three weeks after axotomy. The alpha cells underwent markedly enhanced neurofibrillar staining of their dendrites prior to degeneration. The Nissl material of the cell bodies diminished as the cells degenerated but we have not observed pyknotic nuclei. The dendritic trees of some axotomised gamma cells were also revealed by the neurofibrillar stain three weeks after axotomy. These results show that retinal ganglion cells do not degenerate by a dying back process. We suggest that the rapid degeneration of the beta ganglion cell population comes about by excitotoxic cell death, a consequence of their large glutamatergic input from bipolar cells. The degenerating beta ganglion cells have the morphological appearance of cells undergoing apoptosis. 相似文献
17.
18.
Regulation of the antibody response to sheep erythrocytes by monoclonal IgG antibodies 总被引:1,自引:0,他引:1
Ilana Zalcberg Quintana Angela V. Silveira Güran Mller 《European journal of immunology》1987,17(9):1343-1349
Monoclonal antibodies directed against sheep erythrocytes of the isotypes IgG1, IgG2b and IgG2a were used to analyze the specificity of antibody-induced suppression of the immune response. It was first shown that all monoclonals reacted against different antigenic determinants and they all suppressed the immune response to sheep erythrocytes when given shortly after the antigen to more than 50% as compared to 90-96% inhibition obtained with a polyclonal antiserum. Increasing the doses of monoclonals did not increase suppression. However, two different monoclonals administered together caused an additive, but not a synergistic inhibitory effect. No enhancement of the immune response was observed with any of the Ig classes tested. These findings show that four different antigenic determinants on sheep erythrocytes induced the synthesis of corresponding antibodies, with little or no signs of a dominant determinant. Passively administered monoclonal antibodies, even at supraoptimal doses, never suppressed the immune response to the same extent as a polyclonal antiserum, suggesting that each monoclonal only suppressed the synthesis of the corresponding antibody and did not affect antibody synthesis to other determinants. 相似文献
19.
Central chemoreceptors and sympathetic vasomotor outflow 总被引:1,自引:1,他引:1
Thiago S. Moreira Ana C. Takakura Eduardo Colombari Patrice G. Guyenet 《The Journal of physiology》2006,577(1):369-386
The present study explores how elevations in brain P CO2 increase the sympathetic nerve discharge (SND). SND, phrenic nerve discharge (PND) and putative sympathoexcitatory vasomotor neurons of the rostral ventrolateral medulla (RVLM) were recorded in anaesthetized sino-aortic denervated and vagotomized rats. Hypercapnia (end-expiratory CO2 from 5% to 10%) increased SND (97 ± 6%) and the activity of RVLM neurons (67 ± 4%). Injection of kynurenic acid (Kyn, ionotropic glutamate receptor antagonist) into RVLM or the retrotrapezoid nucleus (RTN) eliminated or reduced PND, respectively, but did not change the effect of CO2 on SND. Bilateral injection of Kyn or muscimol into the rostral ventral respiratory group (rVRG-pre-Bötzinger region, also called CVLM) eliminated PND while increasing the stimulatory effect of CO2 on SND. Muscimol injection into commissural part of the solitary tract nucleus (commNTS) had no effect on PND or SND activation by CO2 . As expected, injection of Kyn into RVLM or muscimol into commNTS virtually blocked the effect of carotid body stimulation on SND in rats with intact carotid sinus nerves. In conclusion, CO2 increases SND by activating RVLM sympathoexcitatory neurons. The relevant central chemoreceptors are probably located within or close to RVLM and not in the NTS or in the rVRG-pre-Bötzinger/CVLM region. RVLM sympathoexcitatory neurons may be intrinsically pH-sensitive and/or receive excitatory synaptic inputs from RTN chemoreceptors. Activation of the central respiratory network reduces the overall sympathetic response to CO2 , presumably by activating barosensitive CVLM neurons and inhibiting RTN chemoreceptors. 相似文献
20.
Costa Davidson Ribeiro Pessoa Diego Rodrigues Seefeldt Vanessa Borelli Costa David Ribeiro Maia Daniel Tineu Leite dos Santos Maciel Thiago Mota Brenda Barros Magalhães Delpasso Carolina Alves Ribeiro Camila Alves Delpasso Nicolau Renata Amadei 《Lasers in medical science》2021,36(8):1681-1689
Lasers in Medical Science - This study compared the effects of LED therapy associated with occlusal splint (OS) on the signs and symptoms of temporomandibular disorder (TMD). In this randomized,... 相似文献