353 research outputs found
Kaposi's Sarcoma-Associated Herpesvirus Latency Locus Compensates for Interleukin-6 in Initial B Cell Activation
Interleukin 6 (IL-6) is considered a proliferation and survival factor for B cells. To assess the role of IL-6 in Kaposi sarcoma-associated herpesvirus (KSHV) latency, KSHV latency locus-transgenic mice (referred to as latency mice) lacking IL-6 were evaluated. IL-6 −/− latency mice had the same phenotypes as the latency mice, i.e., increased frequency of marginal zone B cells, hyperplasia, and hyperglobulinemia, indicating that the KSHV latency locus, which includes all viral microRNAs (miRNAs), can compensate for lack of IL-6 in premalignant B cell activation
Suppression of HBV by Tenofovir in HBV/HIV coinfected patients : a systematic review and meta-analysis
Background: Hepatitis B coinfection is common in HIV-positive individuals and as antiretroviral therapy has made death due to AIDS less common, hepatitis has become increasingly important. Several drugs are available to treat hepatitis B. The most potent and the one with the lowest risk of resistance appears to be tenofovir (TDF). However there are several questions that remain unanswered regarding the use of TDF, including the proportion of patients that achieves suppression of HBV viral load and over what time, whether suppression is durable and whether prior treatment with other HBV-active drugs such as lamivudine, compromises the efficacy of TDF due to possible selection of resistant HBV strains.
Methods: A systematic review and meta-analysis following PRISMA guidelines and using multilevel mixed effects logistic regression, stratified by prior and/or concomitant use of lamivudine and/or emtricitabine.
Results: Data was available from 23 studies including 550 HBV/HIV coinfected patients treated with TDF. Follow up was for up to seven years but to ensure sufficient power the data analyses were limited to three years. The overall proportion achieving suppression of HBV replication was 57.4%, 79.0% and 85.6% at one, two and three years, respectively. No effect of prior or concomitant 3TC/FTC was shown. Virological rebound on TDF treatment was rare.
Interpretation: TDF suppresses HBV to undetectable levels in the majority of HBV/HIV coinfected patients with the proportion fully suppressed continuing to increase during continuous treatment. Prior treatment with 3TC/FTC does not compromise efficacy of TDF treatment. The use of combination treatment with 3TC/FTC offers no significant benefit over TDF alone
Quantitative Excited State Spectroscopy of a Single InGaAs Quantum Dot Molecule through Multi-million Atom Electronic Structure Calculations
Atomistic electronic structure calculations are performed to study the
coherent inter-dot couplings of the electronic states in a single InGaAs
quantum dot molecule. The experimentally observed excitonic spectrum [12] is
quantitatively reproduced, and the correct energy states are identified based
on a previously validated atomistic tight binding model. The extended devices
are represented explicitly in space with 15 million atom structures. An excited
state spectroscopy technique is presented in which the externally applied
electric field is swept to probe the ladder of the electronic energy levels
(electron or hole) of one quantum dot through anti-crossings with the energy
levels of the other quantum dot in a two quantum dot molecule. This technique
can be applied to estimate the spatial electron-hole spacing inside the quantum
dot molecule as well as to reverse engineer quantum dot geometry parameters
such as the quantum dot separation. Crystal deformation induced piezoelectric
effects have been discussed in the literature as minor perturbations lifting
degeneracies of the electron excited (P and D) states, thus affecting
polarization alignment of wave function lobes for III-V Heterostructures such
as single InAs/GaAs quantum dots. In contrast this work demonstrates the
crucial importance of piezoelectricity to resolve the symmetries and energies
of the excited states through matching the experimentally measured spectrum in
an InGaAs quantum dot molecule under the influence of an electric field. Both
linear and quadratic piezoelectric effects are studied for the first time for a
quantum dot molecule and demonstrated to be indeed important. The net
piezoelectric contribution is found to be critical in determining the correct
energy spectrum, which is in contrast to recent studies reporting vanishing net
piezoelectric contributions.Comment: Accepted for publication in IOP Nanotechnology Journa
Holographic Charged Fluid with Anomalous Current at Finite Cutoff Surface in Einstein-Maxwell Gravity
The holographic charged fluid with anomalous current in Einstein-Maxwell
gravity has been generalized from the infinite boundary to the finite cutoff
surface by using the gravity/fluid correspondence. After perturbing the boosted
Reissner-Nordstrom (RN)-AdS black brane solution of the Einstein-Maxwell
gravity with the Chern-Simons term, we obtain the first order perturbative
gravitational and Maxwell solutions, and calculate the stress tensor and
charged current of the dual fluid at finite cutoff surfaces which contains
undetermined parameters after demanding regularity condition at the future
horizon. We adopt the Dirichlet boundary condition and impose the Landau frame
to fix these parameters, finally obtain the dependence of transport
coefficients in the dual stress tensor and charged current on the arbitrary
radical cutoff . We find that the dual fluid is not conformal, but it has
vanishing bulk viscosity, and the shear viscosity to entropy density ratio is
universally . Other transport coefficients of the dual current turns
out to be cutoff-dependent. In particular, the chiral vortical conductivity
expressed in terms of thermodynamic quantities takes the same form as that of
the dual fluid at the asymptotic AdS boundary, and the chiral magnetic
conductivity receives a cutoff-dependent correction which vanishes at the
infinite boundary.Comment: 19 pages, v2: references added, v3: typos corrected, v5: typos
corrected, version accepted for publication in JHE
The use of multi-omics data and approaches in breast cancer immunotherapy: a review
Breast cancer is projected to be the most common cancer in women in 2020 in the USA. Despite high remission rates treatment side effects remain an issue, hence the interest in novel approaches such as immunotherapies which aim to utilize patients’ immune systems to target cancer cells. This review summarizes the basics of breast cancer including staging and treatment options, followed by a discussion on immunotherapy, including immune checkpoint blockade. After this, examples of the role of omics-type data and computational biology/bioinformatics in breast cancer are explored. Ultimately, there are several promising areas to investigate such as the prediction of neoantigens and the use of multi-omics data to direct research, with noted appropriate in clinical trial design in terms of end points
Phylogeographic reconstruction of a bacterial species with high levels of lateral gene transfer
Background Phylogeographic reconstruction of some bacterial populations is hindered by low diversity coupled with high levels of lateral gene transfer. A comparison of recombination levels and diversity at seven housekeeping genes for eleven bacterial species, most of which are commonly cited as having high levels of lateral gene transfer shows that the relative contributions of homologous recombination versus mutation for Burkholderia pseudomallei is over two times higher than for Streptococcus pneumoniae and is thus the highest value yet reported in bacteria. Despite the potential for homologous recombination to increase diversity, B. pseudomallei exhibits a relative lack of diversity at these loci. In these situations, whole genome genotyping of orthologous shared single nucleotide polymorphism loci, discovered using next generation sequencing technologies, can provide very large data sets capable of estimating core phylogenetic relationships. We compared and searched 43 whole genome sequences of B. pseudomallei and its closest relatives for single nucleotide polymorphisms in orthologous shared regions to use in phylogenetic reconstruction. Results Bayesian phylogenetic analyses of >14,000 single nucleotide polymorphisms yielded completely resolved trees for these 43 strains with high levels of statistical support. These results enable a better understanding of a separate analysis of population differentiation among >1,700 B. pseudomallei isolates as defined by sequence data from seven housekeeping genes. We analyzed this larger data set for population structure and allele sharing that can be attributed to lateral gene transfer. Our results suggest that despite an almost panmictic population, we can detect two distinct populations of B. pseudomallei that conform to biogeographic patterns found in many plant and animal species. That is, separation along Wallace's Line, a biogeographic boundary between Southeast Asia and Australia. Conclusion We describe an Australian origin for B. pseudomallei, characterized by a single introduction event into Southeast Asia during a recent glacial period, and variable levels of lateral gene transfer within populations. These patterns provide insights into mechanisms of genetic diversification in B. pseudomallei and its closest relatives, and provide a framework for integrating the traditionally separate fields of population genetics and phylogenetics for other bacterial species with high levels of lateral gene transfer
Innate Immune Responses of Pulmonary Epithelial Cells to Burkholderia pseudomallei Infection
10.1371/journal.pone.0007308PLoS ONE410
The synthesis of chalcones as anticancer prodrugs and their bioactivation in CYP1 expressing breast cancer cells
The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI linkAbstract: Background: Although the expression levels of many P450s differ between tumour and
corresponding normal tissue, CYP1B1 is one of the few CYP subfamilies which is significantly
and consistently overexpressed in tumours. CYP1B1 has been shown to be active within tumours
and is capable of metabolising a structurally diverse range of anticancer drugs. Because of this,
and its role in the activation of procarcinogens, CYP1B1 is seen as an important target for anticancer
drug development.
Objectives: To synthesise a series of chalcone derivatives based on the chemopreventative agent
DMU-135 and investigate their antiproliferative activities in human breast cancer cell lines which
express CYP1B1 and CYP1A1.
Method: A series of chalcones were synthesised in yields of 43-94% using the Claisen-Schmidt
condensation reaction. These were screened using a MTT assay against a panel of breast cancer
cell lines which have been characterised for CYP1 expression.
Results: A number of derivatives showed promising antiproliferative activities in human breast
cancer cell lines which express CYP1B1 and CYP1A1, while showing significantly lower toxicity
towards a non-tumour breast cell line with no CYP expression. Experiments using the CYP1 inhibitors
acacetin and -naphthoflavone provided supporting evidence for the involvement of CYP1
enzymes in the bioactivation of these compounds.
Conclusions: Chalcones show promise as anticancer agents with evidence suggesting that CYP1
activation of these compounds may be involved
An Integrated TCGA Pan-Cancer Clinical Data Resource to Drive High-Quality Survival Outcome Analytics
For a decade, The Cancer Genome Atlas (TCGA) program collected clinicopathologic annotation data along with multi-platform molecular profiles of more than 11,000 human tumors across 33 different cancer types. TCGA clinical data contain key features representing the democratized nature of the data collection process. To ensure proper use of this large clinical dataset associated with genomic features, we developed a standardized dataset named the TCGA Pan-Cancer Clinical Data Resource (TCGA-CDR), which includes four major clinical outcome endpoints. In addition to detailing major challenges and statistical limitations encountered during the effort of integrating the acquired clinical data, we present a summary that includes endpoint usage recommendations for each cancer type. These TCGA-CDR findings appear to be consistent with cancer genomics studies independent of the TCGA effort and provide opportunities for investigating cancer biology using clinical correlates at an unprecedented scale. Analysis of clinicopathologic annotations for over 11,000 cancer patients in the TCGA program leads to the generation of TCGA Clinical Data Resource, which provides recommendations of clinical outcome endpoint usage for 33 cancer types
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