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排序方式: 共有625条查询结果,搜索用时 15 毫秒
581.
Gianfranco Arroyo Luz Toribio Ana Vargas-Calla Juan F. Calcina Edson Bernal Nancy Chile Miguel Zambrano Luis A. Gomez-Puerta Juan Chacaltana Miguel Marzal Javier A. Bustos Manuela R. Verastegui Robert H. Gilman Seth E. ONeal Armando E. Gonzalez Hector H. Garcia for The Cysticercosis Working Group in Peru 《PLoS neglected tropical diseases》2022,16(6)
BackgroundNeurocysticercosis (NCC) is the infection of the human central nervous system (CNS) by Taenia solium larvae that cause significant neurological morbidity. Studies on NCC pathophysiology, host-parasite interactions or therapeutic agents are limited by the lack of suitable animal models. We have previously reported that carotid injection of activated T. solium oncospheres directs parasites into the CNS and consistently reproduces NCC. This study assessed the minimal dose required to consistently obtain NCC by intracarotid oncosphere injection and compared antigen and antibody response profiles by dose-group.Methods/Principal findingsThree groups of pigs were infected with either 2500 (n = 10), 5000 (n = 11), or 10000 (n = 10) oncospheres. Two pigs died during the study. Necropsy exam at day 150 post-infection (PI) demonstrated viable NCC in 21/29 pigs (72.4%), with higher NCC rates with increasing oncosphere doses (4/9 [44.4%], 9/11 [81.8%] and 8/9 [88.9%] for 2500, 5000, and 10000 oncospheres respectively, P for trend = 0.035). CNS cyst burden was also higher in pigs with increasing doses (P for trend = 0.008). Viable and degenerated muscle cysticerci were also found in all pigs, with degenerated cysticerci more frequent in the 2500 oncosphere dose-group. All pigs were positive for circulating parasite antigens on ELISA (Ag-ELISA) from day 14 PI; circulating antigens markedly increased at day 30 PI and remained high with plateau levels in pigs infected with either 5000 or 10000 oncospheres, but not in pigs infected with 2500 oncospheres. Specific antibodies appeared at day 30 PI and were not different between dose-groups.Conclusion/SignificanceIntracarotid injection of 5000 or more oncospheres produces high NCC rates in pigs with CNS cyst burdens like those usually found in human NCC, making this model appropriate for studies on the pathogenesis of NCC and the effects of antiparasitic treatment. 相似文献
582.
Chimeric yellow fever virus 17D-Japanese encephalitis virus vaccine: dose-response effectiveness and extended safety testing in rhesus monkeys 总被引:7,自引:0,他引:7 下载免费PDF全文
Monath TP Levenbook I Soike K Zhang ZX Ratterree M Draper K Barrett AD Nichols R Weltzin R Arroyo J Guirakhoo F 《Journal of virology》2000,74(4):1742-1751
ChimeriVax-JE is a live, attenuated recombinant virus prepared by replacing the genes encoding two structural proteins (prM and E) of yellow fever 17D virus with the corresponding genes of an attenuated strain of Japanese encephalitis virus (JE), SA14-14-2 (T. J. Chambers et al., J. Virol. 73:3095-3101, 1999). Since the prM and E proteins contain antigens conferring protective humoral and cellular immunity, the immune response to vaccination is directed principally at JE. The prM-E genome sequence of the ChimeriVax-JE in diploid fetal rhesus lung cells (FRhL, a substrate acceptable for human vaccines) was identical to that of JE SA14-14-2 vaccine and differed from sequences of virulent wild-type strains (SA14 and Nakayama) at six amino acid residues in the envelope gene (E107, E138, E176, E279, E315, and E439). ChimeriVax-JE was fully attenuated for weaned mice inoculated by the intracerebral (i.c.) route, whereas commercial yellow fever 17D vaccine (YF-Vax) caused lethal encephalitis with a 50% lethal dose of 1.67 log(10) PFU. Groups of four rhesus monkeys were inoculated by the subcutaneous route with 2.0, 3.0, 4.0, and 5. 0 log(10) PFU of ChimeriVax-JE. All 16 monkeys developed low viremias (mean peak viremia, 1.7 to 2.1 log(10) PFU/ml; mean duration, 1.8 to 2.3 days). Neutralizing antibodies appeared between days 6 and 10; by day 30, neutralizing antibody responses were similar across dose groups. Neutralizing antibody titers to the homologous (vaccine) strain were higher than to the heterologous wild-type JE strains. All immunized monkeys and sham-immunized controls were challenged i.c. on day 54 with 5.2 log(10) PFU of wild-type JE. None of the immunized monkeys developed viremia or illness and had mild residual brain lesions, whereas controls developed viremia, clinical encephalitis, and severe histopathologic lesions. Immunized monkeys developed significant (>/=4-fold) increases in serum and cerebrospinal fluid neutralizing antibodies after i.c. challenge. In a standardized test for neurovirulence, ChimeriVax-JE and YF-Vax were compared in groups of 10 monkeys inoculated i.c. and analyzed histopathologically on day 30. Lesion scores in brains and spinal cord were significantly higher for monkeys inoculated with YF-Vax. ChimeriVax-JE meets preclinical safety and efficacy requirements for a human vaccine; it appears safer than yellow fever 17D vaccine but has a similar profile of immunogenicity and protective efficacy. 相似文献
583.
584.
585.
David Gonzlez del Portillo Beatriz Arroyo Guillermo García Simn Manuel B. Morales 《Ecology and evolution》2021,11(7):3219
Agriculture intensification threatens farmland bird populations because, among other reasons, it reduces the availability of food resources required to rear their offspring. In our study, we sampled and analyzed total arthropod abundance, biomass and richness, and orthopteran and coleopteran abundance and biomass in different agricultural habitats (alfalfa fields, stubble fields, grazed fields, and field margins) across 4 study localities with different levels of agriculture abandonment–intensification, comparing between areas used and not used by one of the most threatened farmland birds in Europe, the little bustard (Tetrax tetrax), during the chick‐rearing season. Field margins were the taxonomically richest habitat, while alfalfa fields presented significantly higher total arthropod abundance and biomass than other habitats. All arthropod variables were the highest in the localities with clear conservation‐focused agrarian management, and the lowest in the most intensive one. Areas used by little bustards had higher orthopteran and coleopteran abundance and biomass than nonused areas, except for coleopteran biomass in grazed fields. These results highlight the relevance of these arthropods for the species, the importance of dry alfalfa fields as food reservoirs in this critical time of year, the food scarcity in sites where agrarian management disregards farmland bird conservation, and the role of stubbles as providers of food resources during the chick‐rearing season in areas used by the species. The adequate management of alfalfa fields and stubbles to provide those key resources seems crucial to improve little bustard breeding success. 相似文献
586.
B. Arroyo 《Bird Study》2013,60(3):383-384
587.
Juan Carlos Senar José Carrillo‐Ortiz Lluïsa Arroyo 《Journal of Field Ornithology》2012,83(2):180-185
ABSTRACT Most parakeets, parrots, and cockatoos are difficult to mark because of their strong beaks and ability to manipulate items with their feet. We developed a marking method that consists of a numbered tag hung on a neck collar. We used this method to successfully monitor Monk Parakeets (Myiopsitta monachus) and Ring‐necked Parakeets (Psittacula krameri) in Barcelona, Spain, from 2003 to 2009. We marked 881 Monk Parakeets and 88 Ring‐necked Parakeets with collars. Fifteen tags placed on adult Monk Parakeets in 2003 (N= 57) lasted until 2008 and nine until 2009. Three of 12 Ring‐necked Parakeets marked in 2003 were resighted in 2008. We estimated that 4.5% of Monk Parakeets and 5.8% of Ring‐necked Parakeets lost their tags, with median intervals between attachment and tag loss of 347 and 370 d, respectively. Behavioral observations revealed no differences in the time budgets of marked and unmarked Monk Parakeets. In addition, the mass of marked Monk Parakeets did not change between successive recaptures. These results suggest that neck collars had no adverse effects on the birds. Neck collars may also be a suitable marking method for other psittacines, with stronger, more durable components likely needed for larger species. 相似文献
588.
A case of squamous cell carcinoma associated with amebiasis is presented. Protozoa identified as Entamoeba histolytica were found in a routine Papanicolaou smear and in the cervical biopsy of a young woman following the initial diagnosis of cervical cancer and the institution of a radiation therapy regimen. No amoebae were found in repeated stool specimens. The late detection and diagnosis of amebiasis precluded any possible changes in the management of the case. Initial follow-up for the carcinoma demonstrated that the patient was not responding well to therapy; her failure to return to the clinic precluded long-term follow-up and treatment for the amebiasis. 相似文献
589.
Angélica Domingues Hristov Maria Carmen Arroyo Sanchez José Jarbas Bittencourt Ferreira Giselle Fernandes Maciel de Castro Lima Juliana Inoue Maria de Jesus Costa-Nascimento Arianni Rondelli Sanchez Eduardo Milton Ramos-Sanchez Silvia Maria Di Santi 《Memórias do Instituto Oswaldo Cruz》2014,109(8):1014-1020
Studies on autochthonous malaria in low-transmission areas in Brazil have acquired
epidemiological relevance because they suggest continued transmission in what remains
of the Atlantic Forest. In the southeastern portion of the state of São Paulo,
outbreaks in the municipality of Juquitiba have been the focus of studies on the
prevalence of Plasmodium, including asymptomatic cases. Data on the occurrence of the
disease or the presence of antiplasmodial antibodies in pregnant women from this
region have not previously been described. Although Plasmodium falciparum in pregnant
women has been widely addressed in the literature, the interaction of Plasmodium
vivax and Plasmodium malariae with this cohort has been poorly explored to date. We
monitored the circulation of Plasmodium in pregnant women in health facilities
located in Juquitiba using thick blood film and molecular protocols, as well as
immunological assays, to evaluate humoural immune parameters. Through real-time and
nested polymerase chain reaction, P. vivax and P. malariae were detected for the
first time in pregnant women, with a positivity of 5.6%. Immunoassays revealed the
presence of IgG antibodies: 44% for ELISA-Pv, 38.4% for SD-Bioline-Pv and 18.4% for
indirect immunofluorescence assay-Pm. The high prevalence of antibodies showed
significant exposure of this population to Plasmodium. In regions with similar
profiles, testing for a malaria diagnosis might be indicated in prenatal care. 相似文献
590.