1,510 research outputs found

    Gene Delivery to Nonhuman Primate Preimplantation Embryos Using Recombinant Adeno-Associated Virus

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    Delivery of genome editing tools to mammalian zygotes has revolutionized animal modeling. However, the mechanical delivery method to introduce genes and proteins to zygotes remains a challenge for some animal species that are important in biomedical research. Here, an approach to achieve gene delivery and genome editing in nonhuman primate embryos is presented by infecting zygotes with recombinant adeno-associated viruses (rAAVs). Together with previous reports from the authors of this paper and others, this approach is potentially applicable to a broad range of mammals. In addition to genome editing and animal modeling, this rAAV-based method can facilitate gene function studies in early-stage embryos

    Weakly coupled lithospheric extension in southern Tibet

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    AbstractWest–east extension is a prominent tectonic feature of southern and central Tibet despite ongoing north–south (N–S) convergence between India and Eurasia. Knowledge of deep structure beneath the N–S trending rifts is key to evaluating models proposed for their origin, including gravitational collapse, oblique convergence along the arcuate plate boundary, and mantle upwelling. We model direct S and Moho-reflected SsPmp phases at teleseismic distances to constrain variations in crustal thickness across the major rifts crossed by a ∼900-km long, W–E broadband array in the Lhasa Terrane. Crustal thicknesses are ∼70–80 km. However, Moho depth decreases by ∼10 km within a horizontal distance of 100 km west of the Yadong–Gulu rift (YGR) and Nyainquentanghla mountains (NQTL). This Moho uplift, taken with deep, extensional focal mechanisms and reduced seismic velocity in the upper mantle, suggests that asthenospheric upwelling has significantly contributed to the pattern of extension across the YGR and NQTL. The ∼100-km separation between surface rift and Moho uplift is likely enabled by partial decoupling across a ductile middle crust

    Silica nanofibrous membranes for the separation of heterogeneous azeotropes

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    Nanofibrous materials produced through electrospinning are characterized by a high porosity, large specific surface area, and high pore interconnectivity and, therefore, show potential for, e.g., separation and filtration. The development of more inert nanofibers with higher thermal and chemical resistance extends the application field to high-end purification. Silica nanofibrous membranes produced by direct electrospinning of a sol-gel solution without a sacrificing carrier, starting from tetraethoxysilane, meet these challenging requirements. After electrospinning the membrane is highly hydrophobic. Storage under dry conditions preserves this property. Oppositely, a superhydrophilic membrane is obtained by storage under high humidity (month scale). This switch is caused by the reaction of ethoxy groups, present due to incomplete hydrolysis of the precursor, with moisture in the air, resulting in an increased amount of silanol groups. This transition can be accelerated to hour scale by applying a heat treatment, with the additional increase in cross-linking density for temperatures above 400 degrees C, enabling applications that make use of hydrophobic and hydrophilic membranes by tuning the functionalization. It is showcased that upon designing the water repellent or absorbing nature of the silica material, fast gravity-driven membrane separation of heterogeneous azeotropes can be achieved

    A review of mineral carbonation technologies to sequester CO2

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    Separable Bilayer Microfiltration Device for Viable Label-free Enrichment of Circulating Tumour Cells

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    The analysis of circulating tumour cells (CTCs) in cancer patients could provide important information for therapeutic management. Enrichment of viable CTCs could permit performance of functional analyses on CTCs to broaden understanding of metastatic disease. However, this has not been widely accomplished. Addressing this challenge, we present a separable bilayer (SB) microfilter for viable size-based CTC capture. Unlike other single-layer CTC microfilters, the precise gap between the two layers and the architecture of pore alignment result in drastic reduction in mechanical stress on CTCs, capturing them viably. Using multiple cancer cell lines spiked in healthy donor blood, the SB microfilter demonstrated high capture efficiency (78–83%), high retention of cell viability (71–74%), high tumour cell enrichment against leukocytes (1.7–2 × 10^3), and widespread ability to establish cultures post-capture (100% of cell lines tested). In a metastatic mouse model, SB microfilters successfully enriched viable mouse CTCs from 0.4–0.6 mL whole mouse blood samples and established in vitro cultures for further genetic and functional analysis. Our preliminary studies reflect the efficacy of the SB microfilter device to efficiently and reliably enrich viable CTCs in animal model studies, constituting an exciting technology for new insights in cancer research

    The Genes Coding for the Conversion of Carbazole to Catechol Are Flanked by IS6100 Elements in Sphingomonas sp. Strain XLDN2-5

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    BACKGROUND: Carbazole is a recalcitrant compound with a dioxin-like structure and possesses mutagenic and toxic activities. Bacteria respond to a xenobiotic by recruiting exogenous genes to establish a pathway to degrade the xenobiotic, which is necessary for their adaptation and survival. Usually, this process is mediated by mobile genetic elements such as plasmids, transposons, and insertion sequences. FINDINGS: The genes encoding the enzymes responsible for the degradation of carbazole to catechol via anthranilate were cloned, sequenced, and characterized from a carbazole-degrading Sphingomonas sp. strain XLDN2-5. The car gene cluster (carRAaBaBbCAc) and fdr gene were accompanied on both sides by two copies of IS6100 elements, and organized as IS6100::ISSsp1-ORF1-carRAaBaBbCAc-ORF8-IS6100-fdr-IS6100. Carbazole was converted by carbazole 1,9a-dioxygenase (CARDO, CarAaAcFdr), meta-cleavage enzyme (CarBaBb), and hydrolase (CarC) to anthranilate and 2-hydroxypenta-2,4-dienoate. The fdr gene encoded a novel ferredoxin reductase whose absence resulted in lower transformation activity of carbazole by CarAa and CarAc. The ant gene cluster (antRAcAdAbAa) which was involved in the conversion of anthranilate to catechol was also sandwiched between two IS6100 elements as IS6100-antRAcAdAbAa-IS6100. Anthranilate 1,2-dioxygenase (ANTDO) was composed of a reductase (AntAa), a ferredoxin (AntAb), and a two-subunit terminal oxygenase (AntAcAd). Reverse transcription-PCR results suggested that carAaBaBbCAc gene cluster, fdr, and antRAcAdAbAa gene cluster were induced when strain XLDN2-5 was exposed to carbazole. Expression of both CARDO and ANTDO in Escherichia coli required the presence of the natural reductases for full enzymatic activity. CONCLUSIONS/SIGNIFICANCE: We predict that IS6100 might play an important role in the establishment of carbazole-degrading pathway, which endows the host to adapt to novel compounds in the environment. The organization of the car and ant genes in strain XLDN2-5 was unique, which showed strong evolutionary trail of gene recruitment mediated by IS6100 and presented a remarkable example of rearrangements and pathway establishments

    Association of preoperative albumin–bilirubin with surgical textbook outcomes following laparoscopic hepatectomy for hepatocellular carcinoma

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    Background and aimsRecently, the effectiveness of “textbook outcomes (TO)” in the evaluation of surgical quality has been recognized by more and more scholars. This study tended to examine the association between preoperative albumin–bilirubin (ALBI) grades and the incidence of achieving or not achieving TO (non-TO) in patients with hepatocellular carcinoma (HCC) undergoing laparoscopic hepatectomy.MethodsThe patients were stratified into two groups: ALBI grade 1 (ALBI ≤ -2.60) and ALBI grade 2/3 (ALBI > -2.60). The characteristics of patients and the incidence of non-TO were compared. Multivariate analyses were performed to determine whether ALBI grade was independently associated with TO.ResultsIn total, 378 patients were enrolled, including 194 patients (51.3%) in the ALBI grade 1 group and 184 patients (48.7%) in the ALBI grade 2/3 group. In the whole cohort, 198 patients (52.4%) did not achieve TO, and the incidence of non-TO in the ALBI grade 2/3 group was obviously higher than that in the ALBI grade 1 group (n = 112, 60.9% vs. n = 86, 44.3%, P = 0.001). The multivariate analyses showed that ALBI grade 2/3 was an independent risk factor for non-TO (OR: 1.95, 95%CI: 1.30–2.94, P = 0.023).ConclusionsMore than half (52.4%) of the patients with hepatocellular carcinoma did not achieve TO after laparoscopic hepatectomy, and preoperative ALBI grade 2/3 was significantly associated with non-TO. Improving the liver function reserve of patients before operation, thereby reducing the ALBI grade, may increase the probability for patients to reach TO and enable patients to benefit more from surgery

    Genetic factors associated with patient-specific warfarin dose in ethnic Indonesians

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    <p>Abstract</p> <p>Background</p> <p><it>CYP2C9 </it>and <it>VKORC1 </it>are two major genetic factors associated with inter-individual variability in warfarin dose. Additionally, genes in the warfarin metabolism pathway have also been associated with dose variance. We analyzed Single Nucleotide Polymorphisms (SNPs) in these genes to identify genetic factors that might confer warfarin sensitivity in Indonesian patients.</p> <p>Methods</p> <p>Direct sequencing method was used to identify SNPs in <it>CYP2C9, VKORC1, CYP4F2, EPHX1, PROC </it>and <it>GGCX </it>genes in warfarin-treated patients. Multiple linear regressions were performed to model the relationship warfarin daily dose requirement with genetic and non-genetic variables measured and used to develop a novel algorithm for warfarin dosing.</p> <p>Results</p> <p>From the 40 SNPs analyzed, <it>CYP2C9 </it>rs17847036 and <it>VKORC1 </it>rs9923231 showed significant association with warfarin sensitivity. In our study population, no significant correlation could be detected between <it>CYP2C9*3, CYP2C9C</it>-65 (rs9332127), <it>CYP4F2 </it>rs2108622, <it>GGCX </it>rs12714145, <it>EPHX1 </it>rs4653436 and <it>PROC </it>rs1799809 with warfarin sensitivity.</p> <p>Conclusions</p> <p><it>VKORC1 </it>rs9923231 AA and <it>CYP2C9 </it>rs17847036 GG genotypes were associated with low dosage requirements of most patients (2.05 ± 0.77 mg/day and 2.09 ± 0.70 mg/day, respectively). <it>CYP2C9 </it>and <it>VKORC1 </it>genetic variants as well as non-genetic factors such as age, body weight and body height account for 15.4% of variance in warfarin dose among our study population. Additional analysis of this combination could allow for personalized warfarin treatment in ethnic Indonesians.</p

    Serum alpha-fetoprotein response as a preoperative prognostic indicator in unresectable hepatocellular carcinoma with salvage hepatectomy following conversion therapy: a multicenter retrospective study

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    BackgroundThis study evaluates the efficacy of alpha-fetoprotein (AFP) response as a surrogate marker for determining recurrence-free survival (RFS) in patients with unresectable hepatocellular carcinoma (uHCC) who undergo salvage hepatectomy following conversion therapy with tyrosine kinase inhibitor (TKI) and anti-PD-1 antibody-based regimen.MethodsThis multicenter retrospective study included 74 patients with uHCC and positive AFP (&gt;20 ng/mL) at diagnosis, who underwent salvage hepatectomy after treatment with TKIs and anti-PD-1 antibody-based regimens. The association between AFP response—defined as a ≥ 80% decrease in final AFP levels before salvage hepatectomy from diagnosis—and RFS post-hepatectomy was investigated.ResultsAFP responders demonstrated significantly better postoperative RFS compared to non-responders (P&lt;0.001). The median RFS was not reached for AFP responders, with 1-year and 2-year RFS rates of 81.3% and 70.8%, respectively. In contrast, AFP non-responders had a median RFS of 7.43 months, with 1-year and 2-year RFS rates at 37.1% and 37.1%, respectively. Multivariate Cox regression analysis identified AFP response as an independent predictor of RFS. Integrating AFP response with radiologic tumor response facilitated further stratification of patients into distinct risk categories: those with radiologic remission experienced the most favorable RFS, followed by patients with partial response/stable disease and AFP response, and the least favorable RFS among patients with partial response/stable disease but without AFP response. Sensitivity analyses further confirmed the association between AFP response and improved RFS across various cutoff values and in patients with AFP ≥ 200 ng/mL at diagnosis (all P&lt;0.05).ConclusionThe “20-80” rule based on AFP response could be helpful for clinicians to preoperatively stratify the risk of patients undergoing salvage hepatectomy, enabling identification and management of those unlikely to benefit from this procedure
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