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81.
Vieira NC Espíndola LS Santana JM Veras ML Pessoa OD Pinheiro SM de Araújo RM Lima MA Silveira ER 《Bioorganic & medicinal chemistry》2008,16(4):1676-1682
Two hundred fifteen compounds isolated from plants of Northeastern Brazil flora have been assayed against epimastigote forms of Trypanosoma cruzi, using the tetrazolium salt MTT as an alternative method. Eight compounds belonging to four different species: Harpalyce brasiliana (Fabaceae), Acnistus arborescens and Physalis angulata (Solanaceae), and Cordia globosa (Boraginaceae) showed significant activity. Among them, a novel and a known pterocarpan, a chalcone, four withasteroids, and a meroterpene benzoquinone were the represented chemical classes. 相似文献
82.
Leonardo Valdés-Reyes Julio Morán Joselín Hernández Magdalena Aguirre-García Laila Gutiérrez-Kobeh 《Experimental parasitology》2009,121(3):199-207
Macrophages (M?) and dendritic cells (DC) are the major target cell populations of the obligate intracellular parasite Leishmania. Inhibition of host cell apoptosis is a method employed by multiple pathogens to ensure their survival in the infected cell. Leishmania has been shown to protect M? and neutrophils from both natural and induced apoptosis. As shown in this study, apoptosis in monocyte-derived dendritic cells (moDC) induced by treatment with camptothecin was downregulated by coincubation with L. mexicana, as detected by morphological analysis of cell nuclei, TUNEL assay, gel electrophoresis of low molecular weight DNA fragments, and annexin V binding to phosphatidylserine. The observed antiapoptotic effect was found to be associated with a significant reduction of caspase-3 activity in moDC. The capacity of L. mexicana to delay apoptosis induction in the infected moDC may have implications for Leishmania pathogenesis by favoring the invasion of its host and the persistence of the parasite in the infected cells. 相似文献
83.
Johanna Thelaus Agneta Andersson Peter Mathisen Anna-Lena Forslund Laila Noppa & Mats Forsman 《FEMS microbiology ecology》2009,67(1):69-80
The natural reservoir of Francisella tularensis , the causative agent of tularaemia, is yet to be identified. We investigated the possibility that Francisella persists in natural aquatic ecosystems between outbreaks. It was hypothesized that nutrient-rich environments, with strong protozoan predation, favour the occurrence of the tularaemia bacterium. To investigate the differences in adaptation to aquatic environments of the species and subspecies of Francisella , we screened 23 strains for their ability to survive grazing by the ciliate Tetrahymena pyriformis . All the Francisella strains tested were consumed at a low rate, although significant differences between subspecies were found. The survival and virulence of gfp -labelled F. tularensis ssp. holarctica were then studied in a microcosm experiment using natural lake water, with varying food web complexities and nutrient availabilities. High nutrient conditions in combination with high abundances of nanoflagellates were found to favour F. tularensis ssp. holarctica . The bacterium was observed both free-living and within the cells of a nanoflagellate. Francisella tularensis entered a viable but nonculturable state during the microcosm experiment. When studied over a longer period of time, F. tularensis ssp. holarctica survived in the lake water, but loss of virulence was not prevented by either high nutrient availability or the presence of predators. 相似文献
84.
Aziz Sheikh Laila Halani Raj Bhopal Gopalakrishnan Netuveli Martyn R. Partridge Josip Car Chris Griffiths Mark Levy 《PLoS medicine》2009,6(10)
Background
There is international interest in enhancing recruitment of minority ethnic people into research, particularly in disease areas with substantial ethnic inequalities. A recent systematic review and meta-analysis found that UK South Asians are at three times increased risk of hospitalisation for asthma when compared to white Europeans. US asthma trials are far more likely to report enrolling minority ethnic people into studies than those conducted in Europe. We investigated approaches to bolster recruitment of South Asians into UK asthma studies through qualitative research with US and UK researchers, and UK community leaders.Methods and Findings
Interviews were conducted with 36 researchers (19 UK and 17 US) from diverse disciplinary backgrounds and ten community leaders from a range of ethnic, religious, and linguistic backgrounds, followed by self-completion questionnaires. Interviews were digitally recorded, translated where necessary, and transcribed. The Framework approach was used for analysis. Barriers to ethnic minority participation revolved around five key themes: (i) researchers'' own attitudes, which ranged from empathy to antipathy to (in a minority of cases) misgivings about the scientific importance of the question under study; (ii) stereotypes and prejudices about the difficulties in engaging with minority ethnic populations; (iii) the logistical challenges posed by language, cultural differences, and research costs set against the need to demonstrate value for money; (iv) the unique contexts of the two countries; and (v) poorly developed understanding amongst some minority ethnic leaders of what research entails and aims to achieve. US researchers were considerably more positive than their UK counterparts about the importance and logistics of including ethnic minorities, which appeared to a large extent to reflect the longer-term impact of the National Institutes of Health''s requirement to include minority ethnic people.Conclusions
Most researchers and community leaders view the broadening of participation in research as important and are reasonably optimistic about the feasibility of recruiting South Asians into asthma studies provided that the barriers can be overcome. Suggested strategies for improving recruitment in the UK included a considerably improved support structure to provide academics with essential contextual information (e.g., languages of particular importance and contact with local gatekeepers), and the need to ensure that care is taken to engage with the minority ethnic communities in ways that are both culturally appropriate and sustainable; ensuring reciprocal benefits was seen as one key way of avoiding gatekeeper fatigue. Although voluntary measures to encourage researchers may have some impact, greater impact might be achieved if UK funding bodies followed the lead of the US National Institutes of Health requiring recruitment of ethnic minorities. Such a move is, however, likely in the short- to medium-term, to prove unpopular with many UK academics because of the added “hassle” factor in engaging with more diverse populations than many have hitherto been accustomed to. Please see later in the article for the Editors'' Summary 相似文献85.
Background
MHC-II restricted CD4+ T cells are dependent on antigen presenting cells (APC) for their activation. APC dysfunction in HIV-infected individuals could accelerate or exacerbate CD4+ T cell dysfunction and may contribute to increased levels of immunodeficiency seen in some patients regardless of their CD4+ T cell numbers. Here we test the hypothesis that APC from HIV-infected individuals have diminished antigen processing and presentation capacity.Methodology/Principal Findings
Monocytes (MN) were purified by immuno-magnetic bead isolation techniques from HLA-DR1.01+ or DR15.01+ HIV-infected and uninfected individuals. MN were analyzed for surface MHC-II expression and for antigen processing and presentation capacity after overnight incubation with soluble antigen or peptide and HLA-DR matched T cell hybridomas. Surface expression of HLA-DR was 20% reduced (p<0.03) on MN from HIV-infected individuals. In spite of this, there was no significant difference in antigen processing and presentation by MN from 14 HIV-infected donors (8 HLA-DR1.01+ and 6 HLA-DR15.01+) compared to 24 HIV-uninfected HLA-matched subjects.Conclusions/Significance
We demonstrated that MHC class II antigen processing and presentation is preserved in MN from HIV-infected individuals. This further supports the concept that this aspect of APC function does not further contribute to CD4+ T cell dysfunction in HIV disease. 相似文献86.
87.
Kyra Megan Jennings Laila Curtis John Harold Burford Sarah Louise Freeman 《BMC veterinary research》2014,10(Z1):S2
Background
Large colon impactions are a common cause of colic in the horse. There are no scientific reports on the clinical presentation, diagnostic tests and treatments used in first opinion practice for large colon impaction cases. The aim of this study was to describe the presentation, diagnostic approach and treatment at the primary assessment of horses with large colon impactions.Methods
Data were collected prospectively from veterinary practitioners on the primary assessment of equine colic cases over a 12 month period. Inclusion criteria were a diagnosis of primary large colon impaction and positive findings on rectal examination. Data recorded for each case included history, signalment, clinical and diagnostic findings, treatment on primary assessment and final case outcome. Case outcomes were categorised into three groups: simple medical (resolved with single treatment), complicated medical (resolved with multiple medical treatments) and critical (required surgery, were euthanased or died). Univariable analysis using one-way ANOVA and Tukey’s post-hoc test, Kruskal Wallis with Dunn’s post-hoc test and Chi squared analysis were used to compare between different outcome categories.Results
1032 colic cases were submitted by veterinary practitioners: 120 cases met the inclusion criteria for large colon impaction. Fifty three percent of cases were categorised as simple medical, 36.6% as complicated medical, and 9.2% as critical. Most cases (42.1%) occurred during the winter. Fifty nine percent of horses had had a recent change in management, 43% of horses were not ridden, and 12.5% had a recent / current musculoskeletal injury. Mean heart rate was 43bpm (range 26-88) and most cases showed mild signs of pain (67.5%) and reduced gut sounds (76%). Heart rate was significantly increased and gut sounds significantly decreased in critical compared to simple medical cases (p<0.05). Fifty different treatment combinations were used, with NSAIDs (93%) and oral fluids (71%) being administered most often.Conclusions
Large colon impactions typically presented with mild signs of colic; heart rate and gut sounds were the most useful parameters to distinguish between simple and critical cases at the primary assessment. The findings of seasonal incidence and associated management factors are consistent with other studies. Veterinary practitioners currently use a wide range of different treatment combinations for large colon impactions.88.
Flávia Cal Sabino Amanda Oliveira Ribeiro Sérgio Tufik Laila Brito Torres José Américo Oliveira Luiz Eugênio Araújo Moraes Mello Jeferson Souza Cavalcante Mario Pedrazzoli 《PloS one》2014,9(9)
The PER3 gene is one of the clock genes, which function in the core mammalian molecular circadian system. A variable number of tandem repeats (VNTR) locus in the 18th exon of this gene has been strongly associated to circadian rhythm phenotypes and sleep organization in humans, but it has not been identified in other mammals except primates. To better understand the evolution and the placement of the PER3 VNTR in a phylogenetical context, the present study enlarges the investigation about the presence and the structure of this variable region in a large sample of primate species and other mammals. The analysis of the results has revealed that the PER3 VNTR occurs exclusively in simiiforme primates and that the number of copies of the primitive unit ranges from 2 to 11 across different primate species. Two transposable elements surrounding the 18th exon of PER3 were found in primates with published genome sequences, including the tarsiiforme Tarsius syrichta, which lacks the VNTR. These results suggest that this VNTR may have evolved in a common ancestor of the simiiforme branch and that the evolutionary copy number differentiation of this VNTR may be associated with primate simiiformes sleep and circadian phenotype patterns. 相似文献
89.
Yousry Hawash Laila Sh. Dorgham Ayman S. Al-Hazmi Mohammed S. Al-Ghamdi 《The Korean journal of parasitology》2014,52(5):479-485
Cryptosporidium diarrhea represents a relevant clinical problem in developing countries. In Al-Taif, a city of Saudi Arabia that lies at an altitude of an around 2 km above the sea level, Cryptosporidium infection seems to be undiagnosed in nearly all clinical laboratories. Furthermore, nothing was published regarding Cryptosporidium-associated diarrhea in this area. The objectives of this research were to (1) determine the Cryptosporidium prevalence among patients with diarrhea and (2) to estimate the performances of 3 different diagnostic methods. Total 180 diarrheal fecal samples, 1 sample per patient, were collected between January and August 2013. Samples were screened for Cryptosporidium with modified Zeihl Neelsen (ZN) microscopy, RIDA® Quick lateral flow (LF) immunotest, and a previously published PCR. The Cryptosporidium prevalence rate was 9.4% (17/180), 10% (18/180), and 11.6% (21/180) by microscopy, LF, and PCR test, respectively. Infection was significantly (P=0.004) predominant among children <5 years (22%) followed by children 5-9 years (11.1%). Although infection was higher in males than in females (16.2% males and 8.5% females), the difference was not statistically significant (P=0.11). Compared to PCR, the sensitivity of microscopy and the LF test were 80.9%, 85.7%, respectively. To conclude, high Cryptosporidium-associated diarrhea was found in this area especially in children ≤9 years. The PCR test showed the best performance followed by the LF test and ZN staining microscopy. The primary health care providers in Al-Taif need to be aware of and do testing for this protozoon, particularly for children seen with diarrhea. 相似文献
90.
The effects of staurosporine, a potent protein kinase C inhibitor, and okadaic acid, a non-TPA tumour promoter, on the adhesion of BHK fibroblast were investigated. Staurosporine at 2.5 and 5 microM was found to stimulate a gradual increase in BHK cell adhesion as well as spreading in 3% serum-containing medium. An increase of approximately 27% over the control value was found at 5 microM concentration in 20 minutes. No such effect was seen in serum-free conditions. Staurosporine at 5 microM, enhanced BHK cell-cell adhesion in 3% serum and in serum-free conditions. Okadaic acid, a phosphatase inhibitor, at concentrations between 0.25 and 1 microgram/ml, was found to inhibit BHK cell-substratum adhesion and spreading. The inhibitory effect was time and concentration dependent. These findings suggest that protein kinase C might be involved in the mechanism(s) controlling BHK cell attachment. 相似文献