共查询到20条相似文献,搜索用时 46 毫秒
1.
Garcia SB Paula JS Giovannetti GS Zenha F Ramalho EM Zucoloto S Silva JS Cunha FQ 《Experimental parasitology》1999,93(4):191-197
Our aim was to investigate the possible involvement of nitric oxide (NO) in peripheral denervation during the acute phase of murine experimental Trypanosoma cruzi infection. Wistar male rats were infected with the Y strain of T. cruzi. One group of animals was also treated with the NO synthase inhibitor N-nitro-l-arginine. A group of uninfected animals was the control. At the 18th day of infection the animals were sacrificed. Quantification of neurons in the colon and heart and tissue parasitism in the heart was performed. Serum concentration of nitrate was measured and a histochemical technique for assessing NADPH-diaphorase activity in the colon was also performed. The infected animals presented a statistically significant decrease in the number of peripheral neurons in the colon and heart and a 2-fold increase in serum NO(3) concentration compared with controls. The animals treated with N-nitro-l-arginine showed almost an absence of NO(3) concentration in the serum and did not show loss of neurons compared with controls. These treated animals displayed a 15-fold increase in tissue parasitism compared with nontreated infected animals. The NADPH-diaphorase activity was much more intense in the muscle layers of the colon of the infected animals than in those of the controls. Taken together, these data suggest that NO is involved in the peripheral denervation observed in the acute phase of experimental T. cruzi infection. 相似文献
2.
Morphological changes and EGF expression in the granular convoluted tubule cells of submandibular glands of Trypanosoma cruzi infected rats 总被引:1,自引:0,他引:1
Moreira A Napimoga MH Benatti BB Silva GA Rocha-Rodrigues DB Clemente-Napimoga JT Vieira GA Alves JB 《Tissue & cell》2008,40(4):293-298
We have previously demonstrated in rats that Chagas' disease affects the salivary glands, by promoting an enlargement of the submandibular gland. In order to further investigate possible functional alterations on infected submandibular glands, the objective of the present study was to analyze epidermal growth factor (EGF) expression on rat submandibular glands during Trypanosoma cruzi infection. Results demonstrated that infected rats presented lower levels of testosterone, and morphological changes in the granular convoluted tubule (GCT) cells of the submandibular glands, along with acinar enlargement and delayed ductal maturation at the developing granular ducts. Immunohistochemistry analysis additionally showed that only few cells immunolabelled with anti-EGF on infected rats during the acute phase of Chagas' disease, while after 64 and 90 days (chronic phase) of infection, EGF expression was similar to non-infected rats. The present findings suggest that at the acute phase of Chagas' disease, lower levels of testosterone may lead to a delayed maturation of GCT, which positively correlates with decreased EGF production by submandibular glands cells. 相似文献
3.
We present the first demonstration of oral transmission of Trypanosoma cruzi to raccoons (Procyon lotor), a natural reservoir host in the United States, by ingestion of trypomastigotes and infected bugs, but not infected tissue. To investigate an alternative, non-vector-based transmission method, we tested the hypothesis that raccoons scavenging on infected hosts results in patent infection. Macerated tissue from selected organs infected with amastigote stages of T. cruzi was orally administered to experimental groups of raccoons (n = 2/group) at 2, 12, or 24 hr after collection of the tissue samples. Additionally, raccoons (n=1) in control groups were inoculated intravenously or per os with trypomastigotes. To further elucidate transmission routes of T. cruzi to raccoons, infected Rhodnius prolixus were fed to raccoons (n=2). Raccoons did not become infected after ingestion of amastigote-infected tissues as evidenced by negative polymerase chain reaction results from blood and tissue, lack of seroconversion, and negative parasitemias. However, per os transmission can occur by ingestion of the infective trypomastigote stage or infected reduviid bugs. We conclude from these findings that oral transmission of T. cruzi may be a route of infection for wildlife in sylvatic cycles, but the scavenging behavior of animals is not likely a significant transmission route. 相似文献
4.
Veloso VM Guedes PM Andrade IM Caldas IS Martins HR Carneiro CM Machado-Coelho GL de Lana M Galvão LM Bahia MT Chiari E 《Memórias do Instituto Oswaldo Cruz》2008,103(6):528-534
The goals of the present study were to evaluate the kinetics of blood parasitism by examination of fresh blood, blood culture (BC) and PCR assays and their correlation with heart parasitism during two years of infection in Beagle dogs inoculated with the Be-78, Y and ABC Trypanosoma cruzi strains. Our results showed that the parasite or its kDNA is easily detected during the acute phase in all infected animals. On the other hand, a reduced number of positive tests were verified during the chronic phase of the infection. The frequency of positive tests was correlated with T. cruzi strain. The percentage of positive BC and blood PCR performed in samples from animals inoculated with Be-78 and ABC strains were similar and significantly larger in relation to animals infected with the Y strain.Comparison of the positivity of PCR tests performed using blood and heart tissue samples obtained two years after infection showed two different patterns associated with the inoculated T. cruzi strain: (1) high PCR positivity for both blood and tissue was observed in animals infected with Be-78 or ABC strains; (2) lower and higher PCR positivity for the blood and tissue, respectively, was detected in animals infected with Y strains. These data suggest that the sensitivity of BC and blood PCR was T. cruzi strain dependent and, in contrast, the heart tissue PCR revealed higher sensitivity regardless of the parasite stock. 相似文献
5.
Talvani A Santana G Barcelos LS Ishii S Shimizu T Romanha AJ Silva JS Soares MB Teixeira MM 《Microbes and infection / Institut Pasteur》2003,5(9):789-796
The generation of an inflammatory response driven by Trypanosoma cruzi or its subproducts appears to be essential for tissue injury and disease pathogenesis. However, this inflammatory response is also relevant in the control of T. cruzi replication. The lipid mediator platelet-activating factor (PAF) has been implicated in a number of pathological conditions characterized by tissue inflammation. In the present study, we aimed at evaluating the role of PAF during T. cruzi infection by using mice that were genetically deficient in the PAF receptor. We observed that infected hearts of PAFR(-/-) mice had an increased number of parasite nests, associated with a more intense inflammatory infiltrate. This was associated with greater parasitemia and lethality. When wild-type and PAFR(-/-) mice were compared, there were no marked changes in the kinetics of the expression of MCP-1, RANTES, IFN-gamma and TNF-alpha in heart tissue of infected animals. Moreover, serum concentrations of TNF-alpha, nitrate and parasite-specific IgM were similar in both groups of mice. In vitro, macrophages from PAFR(-/-) animals did not phagocytose trypomastigote forms when activated with PAF, leukotriene B(4) or MCP-1 and produced less nitric oxide when infected and activated with IFN-gamma. These results are consistent with the hypothesis that endogenous synthesis of PAF and activation of PAF receptors control T. cruzi replication in mice in great part via facilitation of the uptake of the parasite and consequent activation of macrophages. 相似文献
6.
Mitochondrial DNA mutations in the parotid gland of cigarette smokers and non-smokers 总被引:5,自引:0,他引:5
It has previously been demonstrated that mitochondrial DNA (mtDNA) mutations accumulate in the lung and increase in frequency with age. It has also been shown that the level of mtDNA mutations including deletions and base substitutions are elevated in lung tissue of smokers relative to non-smokers. We have previously shown that the 'common' 4977 bp mtDNA deletion is present in the parotid (salivary) gland of smokers and non-smokers and that there is a significant increase in the level of this deletion in Warthins tumour, an oncocytoma of the parotid gland. In this study we used semi-quantitative PCR to confirm the presence of 4977 bp mtDNA deletion in the parotid gland of non-smokers and smokers. Importantly, we show that the deletion accumulates with age regardless of smoking status and that there was no significant difference in the level of the 4977 bp deletion in parotid tissue of smokers and non-smokers. Using strand conformational polymorphism (SSCP) and direct sequencing we also found 5/23 smokers had parotid tissue specific base substitutions: either an A/T to G/C transition at A4767 or a G/C to A/T transition at G4853. These results are evidence of age related increase in the 4977 bp deletion and a higher level of mutations, probably due to oxidative damage, in the parotid gland of smokers. 相似文献
7.
In experimental murine infections with Trypanosoma rangeli it has been observed development immune response to Trypanosoma cruzi. The aim of the present work was to analyze the result of antigenic stimuli and the protective effect with T. rangeli in T. cruzi infections. Mice groups immunized with metacyclic trypomastigotes of T. rangeli (Choach -2V strain), derived from haemolymph and salivary gland and reinfected with T. cruzi virulent populations (Tulahuen strain, SA strain and Dm28c clone) from infected in vitro cells, showed decrease severity of disease outcomes, low parasitemia levels and 100% survival of all mice immunized, in comparison with groups infected only with T. cruzi populations, which demonstrated tissue affection, high parasitemia levels and the death of all animals. The above mentioned data contribute to understand the biological behaviour of T. cruzi and T. rangeli and their interaction with vertebrate host. 相似文献
8.
This study involved 48 subjects of both sexes with ages ranging from 22 years to 90 years. Computerised tomography was used to scan the right and left parotid gland. Gland mean density was calculated in Hounsfield units and regression graphs drawn. A significant fall in gland density was noted with subject age but no differences were noted between male and female subjects. A significant correlation was observed between the mean density of right and left glands in the same individuals. It is postulated that the fall in gland density is related an increase in fibro-fatty tissue within the gland. This study provides evidence that age related changes occur in the human parotid gland from youth to old age. This work supports the earlier findings of Scott's who studied the superficial lobe of the parotid gland histologically and found an increase in adipose tissue in this area of the gland with age. 相似文献
9.
A P Legey A P Pinho S C Chagas Xavier L L Leon A M Jansen 《Memórias do Instituto Oswaldo Cruz》1999,94(3):371-376
Philander opossum and Didelphis marsupialis considered the most ancient mammals and an evolutionary success, maintain parasitism by Trypanosoma cruzi without developing any apparent disease or important tissue lesion. In order to elucidate this well-balanced interaction, we decided to compare the humoral immune response kinetics of the two didelphids naturally and experimentally infected with T. cruzi and immunized by different schedules of parasite antigens, employing an indirect fluorescence antibody test (IFAT). Both didelphids responded with high serological titers to different immunization routes, while the earliest response occurred with the intradermic route. Serological titers of naturally infected P. opossum showed a significant individual variation, while those of D. marsupialis remained stable during the entire follow-up period. The serological titers of the experimentally infected animals varied according to the inoculated strain. Our data suggest that (1) IFAT was sensitive for follow-up of P. opossum in natural and experimental T. cruzi infections; (2) both P. opossum and D. marsupialis are able to mount an efficient humoral immune response as compared to placental mammals; (3) experimentally infected P. opossum and D. marsupialis present distinct patterns of infection, depending on the subpopulation of T. cruzi, (4) the differences observed in the humoral immune responses between P. opossum and D. marsupialis, probably, reflect distinct strategies selected by these animals during their coevolution with T. cruzi. 相似文献
10.
An important target tissue for murine cytomegalovirus (CMV) infection is the submaxillary salivary gland. Submaxillary salivary gland biopsy specimens from BALB/c mice latently infected with murine CMV were examined for murine CMV DNA by in vitro enzymatic amplification using the polymerase chain reaction preceding oligonucleotide hybridization. The amplified sequence was a 152-base pair segment from within the immediate early gene of murine CMV. Biopsy and whole gland specimens from acutely infected BALB/c mice and latently infected, immunosuppressed BALB/c mice were compared for active murine CMV infection. After acute infection with murine CMV, virus was recovered in all cultures of both biopsy and whole salivary gland specimens but from none of the latently infected animals. Reactivated virus was detected by culture of both biopsy (90%) and whole salivary gland specimens (100%) from latently infected mice that received antithymocyte serum. Viral nucleic acid was detected in 90% of biopsy specimens from latently infected animals. Hence, active murine CMV infection can be detected in biopsy specimens from mice with acute and reactivated infection and murine CMV DNA can be amplified and detected in salivary gland biopsy specimens from latently infected animals. Biopsy of this or other target tissues can be useful for obtaining tissue for viral studies where the survival of the animal is important and it is useful to distinguish latent from acute or reactivated infection. 相似文献
11.
At the site of infection, pro-inflammatory cytokines locally produced by macrophages infected with Trypanosoma cruzi can activate surrounding non-professional phagocytes such as fibroblasts, epithelial and endothelial cells, which can be further invaded by the parasite. The effect of secreted soluble factors on the invasion of these cells remains, however, to be established. We show here that two epithelial cell lines become significantly susceptible to the infection by the Y strain of T. cruzi after tumour necrosis factor (TNF) treatment. The increase in the invasion was correlated with the increasing concentration of recombinant TNF added to cultures of HEK293T or LLC-MK2 cells. Supernatants taken from PMA-differentiated human monocytes infected with T. cruzi also increased the permissiveness of epithelial cells to subsequent infection with the parasite, which was inhibited by a TNF monoclonal antibody. Furthermore, the permissiveness induced by TNF was inhibited by TPCK, and led to significant decrease in the number of intracellular parasites, providing evidence that activation of NF-κB induced by TNF favours the invasion of the epithelial cell lines by T. cruzi through yet an unidentified mechanism. Our data indicate that soluble factors released from macrophages early in the infection favours T. cruzi invasion of non-professional phagocytic cells. 相似文献
12.
Trypanosoma cruzi: plasma corticosterone after repetitive stress during the acute phase of infection
Santos CD Prado JC Toldo MP Levy AM Franci CR Caldeira JC 《Experimental parasitology》2007,117(4):405-410
An increased level of plasma corticosterone is one manifestation of severe environmental or physiologic stress. The stress response mediated by the hypothalamic-pituitary-adrenal axis is already known to suppress immunoglobulin production and to impair immune function, but there are few studies relating stress and plasma corticosterone to the outcome of Trypanosoma cruzi infection. In this study, male Wistar rats were infected with the Y strain of T. cruzi and then subjected to repetitive stress by exposure to ether vapor for 1min twice a day during the acute phase of infection. Stressed animals showed decreased lytic antibody activity and lowered levels of peritoneal macrophages. Despite an increase in the weight of the spleen, histological analyses demonstrated tissue alterations, the presence of amastigote nests, and a complete absence of activated lymphoid follicles. These results suggest that stress-induced increases in plasma corticosterone can suppress the immune response and worsen tissue injury during the acute phase of T. cruzi infection. 相似文献
13.
Balb/cJ mice fail to mount an immune response capable of clearing infection with larval Taenia crassiceps. Additionally, male Balb/cJ mice display a lag in larval growth of approximately 3 wk as compared to growth in female mice. It has been reported that male Balb/ cAnN mice generate a protective immune response early in infection, and become permissive to larval growth after they feminize (200-fold increase in serum estradiol and 90% decrease in serum testosterone). To determine if a different strain of Balb/c mice (Balb/cJ) also feminize, serum was collected from infected male mice for 16 wk and levels of 17-beta-estradiol and testosterone were measured via ELISA. In addition, the mounting responses of 12- and 16-wk infected male mice, as well as uninfected control mice, were determined after isolation with a female mouse. The results of these experiments show that male Balb/cJ mice do not feminize during infection with larval T. crassiceps. There was no significant change in serum levels of either 17-beta-estradiol or testosterone during the course of infection (> 16 wk). Moreover, there was no significant decrease in the number of times infected male mice mounted the female mouse as compared to uninfected controls. These results suggest that there may be variances between the substrains of Balb/c mice that lead to the phenotypic differences reported for male Balb/cJ and Balb/cAnN mice. 相似文献
14.
Guedes PM Veloso VM Caliari MV Carneiro CM Souza SM de Lana M Chiari E Bahia MT Galvão LM 《Memórias do Instituto Oswaldo Cruz》2007,102(2):141-147
Trypanosoma cruzi is a hemoflagelate parasite associated with heart dysfunctions causing serious problems in Central and South America. Beagle dogs develop the symptoms of Chagas disease in humans, and could be an important experimental model for better understanding the immunopathogenic mechanisms involved in the chagasic infection. In the present study we investigated the relation among biological factors inherent to the parasite (trypomastigote polymorphism and in vitro infectivity) and immunoglobulin production, inflammation, and fibrosis in the heart of Beagle dogs infected with either T. cruzi Y or Berenice-78 strains. In vitro infectivity of Vero cells as well as the extension of cardiac lesions in infected Beagle was higher for Y strain when compared to Berenice-78 strain. These data suggested that in vitro infectivity assays may correlate with pathogenicity in vivo. In fact, animals infected with Y strain, which shows prevalence of slender forms and high infectivity in vitro, presented cardiomegaly, inflammation, and fibrosis in heart area. Concerning the immunoglobulin production, no statistically significant difference was observed for IgA, IgM or IgG levels among T. cruzi infected animals. However, IgA together IgM levels have shown to be a good marker for the acute phase of Chagas disease. 相似文献
15.
Brazão V Del Vecchio Filipin M Caetano LC Toldo MP Caetano LN do Prado JC 《Experimental parasitology》2008,118(4):549-554
It is well recognized that zinc is an essential trace element, influencing growth and affecting the development and integrity of the immune system. The use of oligoelements as zinc can be considered a tool in modulating the effectiveness of the immune response. In this work zinc was daily and orally supplied in male Wistar rats infected with the Y strain of Trypanosoma cruzi. Parasitemia was evaluated and a significant reduction on blood parasites was observed. In order to check some immunological parameters peritoneal macrophages were counted revealing higher percentages for zinc supplied group. Consequently enhanced concentrations of IFN-gamma was found and for the first time NO was evaluated in T. cruzi infected animals under the influence of zinc therapy, revealing enhanced concentrations when compared to unsupplied counterparts. We conclude that zinc is able to up-regulate the host's immune response against parasite replication. 相似文献
16.
The intracellular distribution of epidermal growth factor was investigated in human parotid gland by immunogold cytochemistry at the electron-microscopy level. Epidermal growth factor immunoreactivity was demonstrated in both acini and ducts. In acinar cells, secretory granules appeared moderately stained, clearly indicating that parotid gland contributes to salivary epidermal growth factor through granule exocytosis. In ductal cells, gold particles were found to decorate numerous cytoplasmic vesicles, particularly abundant in striated duct cells. Since epidermal growth factor reactive vesicles were seen not only at the cellular apex, but nearby lateral plasma membranes as well, it leads to the hypothesis that epidermal growth factor may be discharged both apically into the saliva, and basally into the interstitium. 相似文献
17.
Cabrine-Santos M dos Santos VM de Lima MA de Abreu ME Lages-Silva E Ramírez LE 《Memórias do Instituto Oswaldo Cruz》2003,98(4):523-528
Authors describe genitourinary changes in male hamsters infected and reinfected with Trypanosoma cruzi. Changes in genital organs have been described in human and in experimental chagasic infection. Genital dysfunctions in chronic chagasic patients affect ejaculation, libido and sexual potency, and testis biopsies may show arrested maturation of germ cells, oligozoospermia and azoospermia. Sixty-five male hamsters were inoculated and reinoculated with 2x10 trypomastigotes of T. cruzi VIC strain, and 22 non-infected animals constituted the control group. Animals were necropsied and fragments from testis, epididymis, seminal vesicle and bladder were collected and stained with hematoxylin-eosin. Peroxidase anti-peroxidase procedure was utilized to detect tissue parasitism. T. cruzi nests were found in testis, epididymis and seminal vesicle of these hamsters. Such parasitism plays a role in the origin of genital lesions observed in humans and laboratory animals during chronic chagasic infection. 相似文献
18.
Data on a unique phenomenon of annual involution and neogenesis of thymus gland in hibernating animals are reviewed. In accordance with morphological findings, the annual thymus involution in hibernating animals is close to the age-dependent thymus involution occurring in all mammals once in a lifetime. In opposite, thymus involution in hibernating animals is totally different from the accidental involution. During hibernation, the thymus tissue is substituted by the brown fat tissue. In the spring, thymus gland neogenesis stats with intensive growth of epithelial tissue followed by lymphocyte infiltration and exhaustion of brown tissue. Morphological changes in the thymus gland within the annual cycle were compared with seasonal dynamics of structural and functional changes in peripheral lymphoid organs (spleen, lymphoglandular, peritoneal fluid). A general regularity was observed involving a decreased functional activity of immune cells in autumn, its sharp depression during winter hibernation, and obvious increase in summer with the onset of a season of animal activity. It is supposed that a sharp increase in the tumor necrosis factor (TNF) production observed during short-term awakenings in winter may serve an important link in this unique immune adaptation mechanism. The season changes in cellular TNF secretion suggest a mobilization of protective resources in hibernating animals in autumn and winter, i.e. in seasons when the thymus gland activity is depressed. The annual involution of thymus gland cannot be related to droppings in the environmental or body temperatures, as it comes long before their fall. Additionally, it is not related to ageing, as it occurs already in young hibernating animals. The role of hormones, including melatonine and corticosteroids, in mechanisms regulating thymus gland involution in hibernating animals is discussed. 相似文献
19.
S G Reed 《Journal of immunology (Baltimore, Md. : 1950)》1988,140(12):4342-4347
Recombinant murine IFN-gamma (rMu-IFN-gamma) was demonstrated to be a potent in vivo activator of mouse peritoneal macrophages to kill Trypanosoma cruzi in vitro and to be capable of conferring protection against death from acute T. cruzi infection. Following i.p. injections of rMu-IFN-gamma, resident peritoneal macrophages were cultured and infected with T. cruzi in vitro. Numbers of intracellular parasites were determined at different times thereafter. Ten or 100 micrograms (1 microgram = 6.5 X 10(5) U) of Mu-IFN-gamma, injected both 24 and 4 h before macrophage harvest, induced up to 99% inhibition of T. cruzi. One microgram of rMu-IFN-gamma was not effective under these conditions. In vitro inhibition of T. cruzi by peritoneal macrophages occurred by 24 h after infection and continued until at least 120 h after infection. There were no significant differences in initial parasite uptake by macrophages from IFN-gamma-treated or control mice, indicating that the rMu-IFN-gamma induced parasite killing. One i.p. dose of 10 micrograms was as effective as two doses if the single injection was given 24 h before macrophage harvest. In subsequent experiments, mice were given multiple injections of 10 micrograms rMu-IFN-gamma beginning 24 h before or 2 h after infection with virulent T. cruzi. Mice treated with rMu-IFN-gamma had significantly lower parasitemias and decreased morbidity compared with control mice. Proliferative responses to Con A and antibody responses to SRBC were not significantly lowered in IFN-gamma-treated mice, in contrast to untreated infected controls. All of the IFN-gamma-treated mice survived acute T. cruzi infection, whereas 100% of saline-treated infected mice died. It was demonstrated in this study that rMu-IFN-gamma activated mouse macrophages in vivo to kill T. cruzi and that rMu-IFN-gamma significantly reduced morbidity and immune suppression, and eliminated mortality resulting from acute infection with this parasite. 相似文献
20.
Trypanosoma cruzi, the causative agent of Chagas disease, is able to reproduce intracellularly in many host cell types while in the mammalian host. Although cellular immunity is known to be important in resistance to infection, the ability of immune cells to interfere with the completion of the intracellular growth cycle of T. cruzi has not been described. Using a tissue culture system to study the parasite growth cycle, we have found that spleen cells from infected mice are able to decrease the number of parasites released from infected fibroblasts. Spleen cells from mice infected for as few as 14 days and as long as 300 days display this inhibitory ability. Parasite egress from infected cells is inhibited by factor(s) released by immune cells during coculture with infected fibroblasts. Immune cell depletion studies indicate that the inhibitory activity requires the presence of both CD4+ T cells and mu+ B cells. These results suggest a direct ability of immune cells to somehow interfere with the completion of the intracellular cycle, and this ability may play a role in control of this parasite. 相似文献