640 research outputs found
Existence of solution to a new class of coupled variational-hemivariational inequalities
The objective of this paper is to introduce and study a complicated nonlinear
system, called coupled variational-hemivariational inequalities, which is
described by a highly nonlinear coupled system of inequalities on Banach
spaces. We establish the nonemptiness and compactness of the solution set to
the system. We apply a new method of proof based on a multivalued version of
the Tychonoff fixed point principle in a Banach space combined with the
generalized monotonicity arguments, and elements of the nonsmooth analysis. Our
results improve and generalize some earlier theorems obtained for a very
particular form of the system.Comment: 17
Spatiotemporal in vivo tracking of polyclonal human regulatory T cells (Tregs) reveals a role for innate immune cells in Treg transplant recruitment
Supplemental information is available online at: https://www.sciencedirect.com/science/article/pii/S2329050120302515#appsec2 .Regulatory T cells (Tregs) are emerging as a new cell-based therapy in solid organ transplantation. Adoptive transfer of Tregs has been shown preclinically to protect from graft rejection, and the safety of Treg therapy has been demonstrated in clinical trials. Despite these successes, the in vivo distribution and persistence of adoptively transferred Tregs remained elusive, which hampers clinical translation. Here we isolated human Tregs using a GMP-compatible protocol and lentivirally transduced them with the human sodium iodide symporter to render them traceable in vivo by radionuclide imaging. Engineered human Tregs were characterized for phenotype, survival, suppressive capacity, and reporter function. To study their trafficking behavior, they were subsequently administered to humanized mice with human skin transplants. Traceable Tregs were quantified in skin grafts by non-invasive nano-single-photon emission computed tomography (nanoSPECT)/computed tomography (CT) for up to 40 days, and the results were validated ex vivo. Using this approach, we demonstrated that Treg trafficking to skin grafts was regulated by the presence of recipient Gr-1+ innate immune cells. We demonstrated the utility of radionuclide reporter gene-afforded quantitative Treg in vivo tracking, addressing a fundamental need in Treg therapy development and offering a clinically compatible methodology for future Treg therapy imaging in humans.This work was supported by the British Heart Foundation (RG/13/12/30395), the MRC Centre for Transplantation at King's College London (MR/J006742/1), Cancer Research UK (C48390/A21153), and the Wellcome/EPSRC Centre for Medical Engineering (WT203148/Z/16/Z). This research was funded/supported by the National Institute for Health Research (NIHR) Biomedical Research Centre based at Guyās and St Thomasā NHS Foundation Trust and Kingās College London and/or the NIHR Clinical Research Facility
Persistent viral shedding of SARSāCoVā2 in faeces ā a rapid review
Aim
In addition to respiratory symptoms, COVIDā19 can present with gastrointestinal complaints suggesting possible faecoāoral transmission. The primary aim of this review was to establish the incidence and timing of positive faecal samples for SARSāCoVā2 in patients with COVIDā19.
Methods
A systematic literature review identified studies describing COVIDā19 patients tested for faecal virus. Search terms for MEDLINE included āclinicalā, āfaecesā, āgastrointestinal secretionsā, āstoolā, āCOVIDā19ā, āSARSāCoVā2ā and ā2019ānCoVā. Additional searches were done in the American Journal of Gastroenterology , Gastroenterology , Gut , Lancet Gastroenterology and Hepatology , the World Health Organization Database, the Centre for EvidenceāBased Medicine, New England Journal of Medicine , social media and the National Institute for Health and Care Excellence, bioRxiv and medRxiv preprints. Data were extracted concerning the type of test, number and timing of positive samples, incidence of positive faecal tests after negative nasopharyngeal swabs and evidence of viable faecal virus or faecoāoral transmission of the virus.
Results
Twentyāsix relevant articles were identified. Combining study results demonstrated that 53.9% of those tested for faecal RNA were positive. The duration of faecal viral shedding ranged from 1 to 33 days after a negative nasopharyngeal swab with one result remaining positive 47 days after onset of symptoms. There is insufficient evidence to suggest that COVIDā19 is transmitted via faecally shed virus.
Conclusion
There is a high rate of positive polymerase chain reaction tests with persistence of SARSāCoVā2 in faecal samples of patients with COVIDā19. Further research is needed to confirm if this virus is viable and the degree of transmission through the faecoāoral route. This may have important implications on isolation, recommended precautions and protective equipment for interventional procedures involving the gastrointestinal tract
Molecular characterisation of protist parasites in human-habituated mountain gorillas (Gorilla beringei beringei), humans and livestock, from Bwindi impenetrable National Park, Uganda
Over 60 % of human emerging infectious diseases are zoonotic, and there is growing evidence of the zooanthroponotic transmission of diseases from humans to livestock and wildlife species, with major implications for public health, economics, and conservation. Zooanthroponoses are of relevance to critically endangered species; amongst these is the mountain gorilla (Gorilla beringei beringei) of Uganda. Here, we assess the occurrence of Cryptosporidium, Cyclospora, Giardia, and Entamoeba infecting mountain gorillas in the Bwindi Impenetrable National Park (BINP), Uganda, using molecular methods. We also assess the occurrence of these parasites in humans and livestock species living in overlapping/adjacent geographical regions
A new multi-anticipative car-following model with consideration of the desired following distance
We propose in this paper an extension of the multi-anticipative optimal velocity car-following model to consider explicitly the desired following distance. The model on the following vehicleās acceleration is formulated as a linear function of the optimal velocity and the desired distance, with reaction-time delay in elements. The linear stability condition of the model is derived. The results demonstrate that the stability of traffic flow is improved by introducing the desired following distance, increasing the time gap in the desired following distance or decreasing the reaction-time delay. The simulation results show that by taking into account the desired following distance as well as the optimal velocity, the multi-anticipative model allows longer reaction-time delay in achieving stable traffic flows
The effect Akt2 deletion on tumor development in Pten+/ā mice
The serine/threonine kinase Akt is frequently activated in human cancers and is considered an attractive therapeutic target. However, the relative contributions of the different Akt isoforms to tumorigenesis, and the effect of their deficiencies on cancer development are not well understood. We had previously shown that Akt1 deficiency is sufficient to markedly reduce the incidence of tumors in Pten+/ā mice. Particularly, Akt1 deficiency inhibits endometrial carcinoma and prostate neoplasia in Pten+/ā mice. Here, we analyzed the effect of Akt2 deficiency on the incidence of tumors in Pten+/ā mice. Relative to Akt1, Akt2 deficiency had little-to-no effect on the incidence of prostate neoplasia, endometrial carcinoma, intestinal polyps and adrenal lesions in Pten+/ā mice. However, Akt2 deficiency significantly decreased the incidence of thyroid tumors in Pten+/ā, which correlates with the relatively high level of Akt2 expression in the thyroid. Thus, unlike Akt1 deletion, Akt2 deletion is not sufficient to markedly inhibit tumorigenesis in Pten+/ā mice in most tested tissues. The relatively small effect of Akt2 deletion on the inhibition of tumorigenesis in Pten+/ā mice could be explained, in part, by an insufficient decrease in total Akt activity, due to the relatively lower Akt2 versus Akt1 expression, and relatively high blood insulin levels in Pten+/āAkt2ā/ā mice. The relatively high blood insulin levels in Pten+/āAkt2ā/ā mice may elevate the activity of Akt1, and possibly Akt3, thus, limiting the reduction of total Akt activity and preventing this activity from dropping to a threshold level required to inhibit tumorigenesis
A Mutation in MRH2 Kinesin Enhances the Root Hair Tip Growth Defect Caused by Constitutively Activated ROP2 Small GTPase in Arabidopsis
Root hair tip growth provides a unique model system for the study of plant cell polarity. Transgenic plants expressing constitutively active (CA) forms of ROP (Rho-of-plants) GTPases have been shown to cause the disruption of root hair polarity likely as a result of the alteration of actin filaments (AF) and microtubules (MT) organization. Towards understanding the mechanism by which ROP controls the cytoskeletal organization during root hair tip growth, we have screened for CA-rop2 suppressors or enhancers using CA1-1, a transgenic line that expresses CA-rop2 and shows only mild disruption of tip growth. Here, we report the characterization of a CA-rop2 enhancer (cae1-1 CA1-1) that exhibits bulbous root hairs. The cae1-1 mutation on its own caused a waving and branching root hair phenotype. CAE1 encodes the root hair growth-related, ARM domain-containing kinesin-like protein MRH2 (and thus cae1-1 was renamed to mrh2-3). Cortical MT displayed fragmentation and random orientation in mrh2 root hairs. Consistently, the MT-stabilizing drug taxol could partially rescue the wavy root hair phenotype of mrh2-3, and the MT-depolymerizing drug Oryzalin slightly enhanced the root hair tip growth defect in CA1-1. Interestingly, the addition of the actin-depolymerizing drug Latrunculin B further enhanced the Oryzalin effect. This indicates that the cross-talk of MT and AF organization is important for the mrh2-3 CA1-1 phenotype. Although we did not observe an apparent effect of the MRH2 mutation in AF organization, we found that mrh2-3 root hair growth was more sensitive to Latrunculin B. Moreover, an ARM domain-containing MRH2 fragment could bind to the polymerized actin in vitro. Therefore, our genetic analyses, together with cell biological and pharmacological evidence, suggest that the plant-specific kinesin-related protein MRH2 is an important component that controls MT organization and is likely involved in the ROP2 GTPase-controlled coordination of AF and MT during polarized growth of root hairs
Prediction of Ubiquitination Sites by Using the Composition of k-Spaced Amino Acid Pairs
As one of the most important reversible protein post-translation modifications, ubiquitination has been reported to be involved in lots of biological processes and closely implicated with various diseases. To fully decipher the molecular mechanisms of ubiquitination-related biological processes, an initial but crucial step is the recognition of ubiquitylated substrates and the corresponding ubiquitination sites. Here, a new bioinformatics tool named CKSAAP_UbSite was developed to predict ubiquitination sites from protein sequences. With the assistance of Support Vector Machine (SVM), the highlight of CKSAAP_UbSite is to employ the composition of k-spaced amino acid pairs surrounding a query site (i.e. any lysine in a query sequence) as input. When trained and tested in the dataset of yeast ubiquitination sites (Radivojac et al, Proteins, 2010, 78: 365ā380), a 100-fold cross-validation on a 1ā¶1 ratio of positive and negative samples revealed that the accuracy and MCC of CKSAAP_UbSite reached 73.40% and 0.4694, respectively. The proposed CKSAAP_UbSite has also been intensively benchmarked to exhibit better performance than some existing predictors, suggesting that it can be served as a useful tool to the community. Currently, CKSAAP_UbSite is freely accessible at http://protein.cau.edu.cn/cksaap_ubsite/. Moreover, we also found that the sequence patterns around ubiquitination sites are not conserved across different species. To ensure a reasonable prediction performance, the application of the current CKSAAP_UbSite should be limited to the proteome of yeast
- ā¦