Publications by authors named "Jianchun Zhang"

41 Publications

Ultrasensitive fluorescent detection of telomerase activity based on tetrahedral DNA nanostructures as carriers for DNA-templated silver nanoclusters.

Anal Bioanal Chem 2022 Jan 17. Epub 2022 Jan 17.

The Second Hospital of Nanjing, Nanjing University of Chinese Medicine, Nanjing, 210003, China.

Precise evaluation of telomerase activity is essential for the clinical diagnosis of early tumors. Herein, we have ingeniously designed a tetrahedral DNA nanostructure, with hairpin-shaped DNA probes rich in cytosine bases at four vertices for telomerase detection. The DNA-templated silver nanoclusters can be formed after the addition of Ag. Then the introduction of telomerase adds the single-strand TTAGGG extension, which can "turn on" the fluorescence of silver nanoclusters quickly by the proximity of the resulting guanine-rich sequences to silver nanoclusters and realize accurate detection of telomerase activity. In this study, integration of high stability tetrahedral DNA nanostructure and fluorescence signal amplification of four DNA-templated silver nanoclusters offers the advantage of high sensitivity, with a low detection limit of 1 cell. More than that, this method is low-cost, facile, and feasible for practical clinical applications.
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http://dx.doi.org/10.1007/s00216-022-03883-1DOI Listing
January 2022

Efficacy and Safety of Local Radiotherapy to All Oligometastatic Sites in Elderly Patients with Metachronous Oligometastatic Cancers After Initial Treatment for the Primary Tumor.

Cancer Manag Res 2021 18;13:9247-9259. Epub 2021 Dec 18.

Department of Radiation Oncology, Air Force General Hospital, Beijing, People's Republic of China.

Background And Purpose: This study aimed to investigate the efficacy and safety of maintenance therapy combined with local radiotherapy at all oligometastatic sites (LRTOS) in elderly patients with metachronous oligometastatic cancers (MOC).

Patients And Methods: A total of 242 elderly patients with MOC (≤5 metastases) and primary tumor well controlled after definitive treatment was retrospectively analyzed between August 2014 and February 2020 at Beijing Geriatric Hospital and Air Force General Hospital. Patients were divided into maintenance therapy group (maintenance therapy alone) and local radiotherapy group (maintenance therapy combined with LRTOS).

Results: There were 86 patients in the local radiotherapy group and 156 patients in the maintenance therapy group. The median length of follow-up was 36 months (range, 8.0-62 months). Median overall survival (mOS) was 25 months (95% CI: 21.1-28.9) in the local radiotherapy group and 16 months (95% CI: 14.5-17.6) in the maintenance therapy group (p < 0.001). Multivariate analyses demonstrated that LRTOS (hazard ratio (HR) = 0.49, 95% confidence interval (CI): 0.35-0.67, p < 0.001), good Eastern Cooperative Oncology Group Performance Status (ECOG PS, HR = 0.69, 95% CI: 0.49-0.97, p = 0.032), longer duration between diagnosis of primary tumor and occurrence of progression (HR = 0.87, 95% CI: 0.78-0.97, p = 0.015), and subsequent systemic treatment (HR = 0.52, 95% CI: 0.38-0.72, p < 0.001) were independent predictors of good OS. In patients who did not receive subsequent systemic treatment, their mOS was 21 months (95% CI: 12.8-29.2) for those treated with LRTOS and 14 months (95% CI: 11.4-16.6) for those who did not receive local radiotherapy (p = 0.001). Further multivariate analysis showed that LRTOS was the only independent factor for predicting good OS (HR = 0.47, 95% CI: 0.26-0.83, p = 0.010). Patients with metachronous oligometastatic lung cancer, colorectal cancer, prostate cancer, and breast cancer had higher survival benefits following LRTOS. Most patients suffered from grade 1-2 toxicities, but no treatment-related death was recorded.

Conclusion: This retrospective study shows that elderly patients with MOC treated with LRTOS may have better survival outcomes.
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http://dx.doi.org/10.2147/CMAR.S345871DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8694577PMC
December 2021

Xanthotoxin induced photoactivated toxicity, oxidative stress and cellular apoptosis in Caenorhabditis elegans under ultraviolet A.

Comp Biochem Physiol C Toxicol Pharmacol 2022 Jan 19;251:109217. Epub 2021 Oct 19.

College of Plant Protection, Hainan University, Haikou, Hainan 570228, China. Electronic address:

Xanthotoxin (XAT) is widely present in many kinds of plants. Caenorhabditis elegans, a typical model organism, was used to study the effects of XAT on C. elegans developmental toxicity, neurotoxicity, reproductive toxicity induced under ultraviolet A (UVA), oxidative stress and apoptosis in C. elegans. The results showed that after XAT exposure treatment, the hatchability of C. elegans decreased significantly as the concentration increased; the body length and width increased markedly, the external morphology was swollen; the brood sizes had been decreased; and the frequencies of head thrashes and body bend decreased significantly. At 80 and 100 mg/L, XAT reduced the activities of mitochondrial complex enzymes I and III, resulting in the excessive production of ROS, and inhibited SOD and CAT so that the ROS could not be eliminated over time. ROS accumulation in the bodies further caused the contents of MDA, protein carbonyl and lipofuscin to increase significantly, the mitochondrial membrane potential to be severely damaged, apoptosis to occur, and the apoptosis genes ced-3 and ced-4 to be significantly upregulated. Thus, XAT showed photoactivated toxicity to C. elegans under UVA, which will help people to make full and rational use of plants containing XAT.
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http://dx.doi.org/10.1016/j.cbpc.2021.109217DOI Listing
January 2022

Relationship of Anifrolumab Pharmacokinetics With Efficacy and Safety in Patients With Systemic Lupus Erythematosus.

Rheumatology (Oxford) 2021 Sep 16. Epub 2021 Sep 16.

Centre for Inflammatory Disease Monash Health, Monash University, Melbourne, VIC, Australia.

Objectives: To characterize the relationship of anifrolumab pharmacokinetics with efficacy and safety in patients with moderate to severe SLE despite standard therapy, using pooled data from 2 phase 3 trials.

Methods: TULIP-1 and TULIP-2 were randomized, placebo-controlled, 52-week trials of intravenous anifrolumab (every 4 weeks for 48 weeks). For the exposure-response analysis, BILAG-based Composite Lupus Assessment (BICLA) or SLE Responder Index (SRI[4]) response rates at week 52 in each quartile/tertile of average anifrolumab serum concentration (Cave) were compared for anifrolumab and placebo in all-comers, patients who completed treatment, and interferon gene signature (IFNGS)-high patients who completed treatment, using average marginal effect logistic regression. Relationships between exposure and key safety events were assessed graphically.

Results: Of patients in TULIP-1/TULIP-2 who received anifrolumab (150 mg [n = 91], 300 mg [n = 356]) or placebo (n = 366), 574 completed treatment, of whom 470 were IFNGS high. In the exposure-efficacy analyses, BICLA and SRI(4) treatment differences favoring anifrolumab 300 mg vs placebo were observed across Cave subgroups and all analysis populations. Logistic regression identified Cave as a significant covariate for predicted BICLA response, as higher anifrolumab Cave predicted greater efficacy. There was no evidence of exposure-driven incidence of key safety events through week 52 in patients receiving anifrolumab 150 or 300 mg.

Conclusion: While higher Cave predicted greater efficacy, consistent positive benefit favouring anifrolumab 300 mg vs placebo was observed in BICLA and SRI(4) responses across Cave subgroups in the TULIP trials. There was no evidence of exposure-driven safety events.
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http://dx.doi.org/10.1093/rheumatology/keab704DOI Listing
September 2021

A new method for identification of outliers in immunogenicity assay cut point data.

J Immunol Methods 2020 Sep - Oct;484-485:112817. Epub 2020 Jun 29.

AstraZeneca PLC.

The cut point is an important parameter for immunogenicity assay validation and critical to immunogenicity assessment in clinical trials. FDA (2019) recommends using a statistical approach to derive cut point, with an appropriate outlier removal procedure. In general, the industry follows the methods described in Shankar et al. (2008) and Zhang et al. (2013) among others to determine cut point. Outlier removal is a necessary step during the cut point determination exercise to reduce potential false negative classifications. However, the widely used statistical outlier removal method, namely, Tukey's box-plot method (1.5 times inter-quartile range, IQR), is often found to be overly conservative in the sense that it removes too many "outliers". Tukey's box-plot method can be used to flag potential outliers for further investigation, however, it is not a hypothesis testing based statistical method. Removing these suspected "outliers" will lead to lower cut point which might confound immunogenicity assessment due to the presence of many low false positives. Besides, the very nature of assay analytical variability has a non-negligible adverse impact on the reliability of ADA classification in terms of false positive and false negative, demanding as large as possible contribution from biological variability relative to analytical variability. A new outlier removal procedure, which takes into account the relative magnitude between biological variability and analytical variability within the sample population, is proposed and statistically justified. After sequential removal of analytical and biological outliers, a 5% false positive rate and 1% false positive rate in screening and confirmatory assays, respectively, are still targeted without increasing potential false negatives. Internal data shows that this practice has minimal impact on assay sensitivity and has the advantage of selecting true positive samples. It is shown that the new procedure is more appropriate for cut point determination.
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http://dx.doi.org/10.1016/j.jim.2020.112817DOI Listing
March 2021

Confirmatory cut point has limited ability to make accurate classifications in immunogenicity assays.

Bioanalysis 2020 Feb 24;12(4):245-256. Epub 2020 Feb 24.

Clinical Pharmacology and Safety Sciences, AstraZeneca PLC 1, One MedImmune Way, Gaithersburg, MD 20878, USA.

Competitive inhibition with excess unlabeled drug is used to confirm the presence of antidrug antibodies (ADA) in study samples. We evaluated specific and nonspecific responses from both drug-naive and drug-treated subjects to identify conditions required by the confirmatory assay to make accurate ADA classifications. Nonspecific signal measured in drug-naive samples used to determine assay cut points was uniformly low and close to the screening cut point. Confirmatory assays performed on incurred study samples with nonspecific responses significantly above the level observed during cut point determination resulted in incorrect ADA classifications. Intensity of confirmatory response should be proportional to the screening response and therefore, to ensure accurate ADA classifications, the confirmatory responses cannot be considered as independent but need to be evaluated in relation to the screening responses.
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http://dx.doi.org/10.4155/bio-2019-0283DOI Listing
February 2020

[Research progress on the effects of plateau hypoxia on blood-brain barrier structure and drug permeability].

Zhejiang Da Xue Xue Bao Yi Xue Ban 2019 Dec;48(6):668-673

Department of Pharmacy, First Hospital of Chinese People's Liberation Army, Lanzhou 730000, China.

Drugs for the treatment of central nervous system diseases need to enter the brain tissue through the blood-brain barrier to function. In high altitude hypoxic environment, there are changes in tight junction proteins of blood-brain barrier tissue structure, transporters in astrocytes and endothelial cells and ATP in endothelial cells; at the same time the permeability of the blood-brain barrier is increased. These changes are an important reference for rational drug use in patients with central nervous system disease in the plateau region. This article reviews the research progress on the effects of plateau hypoxia on the structure of the blood-brain barrier and related drug permeability.
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December 2019

Neutrophil extracellular traps induced by IL-8 aggravate atherosclerosis via activation NF-κB signaling in macrophages.

Cell Cycle 2019 Nov 8;18(21):2928-2938. Epub 2019 Sep 8.

Department of Cardiovascular, The First Affiliated Hospital of Harbin Medical University , Harbin , Heilongjiang , China.

Here, we sought to explore the underlying role of interleukin (IL)-8 in neutrophil extracellular traps (NETs) formation during atherosclerosis (AS). The concentration of pro-inflammatory cytokines IL-8, IL-6 and IL-1β was determined by enzyme-linked immunosorbent assay (ELISA). NETs formation was evaluated by immunofluorescence and myeloperoxidase (MPO)-DNA complex ELISA. The mRNA levels of IL-8 and Toll-like receptor 9 (TLR9) were measured by quantitative real-time PCR (qRT-PCR). The phosphorylation levels of NF-κB p65 were detected by western blotting. The hematoxylin and eosin (H&E) staining of atherosclerotic lesion areas was performed in ApoE-deficiency mice. Results showed that patients with AS showed higher serum levels of IL-8, a pro-inflammatory cytokine and NETs. IL-8 interacted with its receptor CXC chemokine receptor 2 (CXCR2) on neutrophils, leading to the formation of NETs via Src and extracellular signal-regulated kinase (ERK) and p38 mitogen-activated protein kinases (MAPK) signaling to aggravate AS progression . PMA-induced NETosis directly upregulated the TLR9/NF-κB pathway in macrophages and subsequently initiated the release of IL-8. Our data reveal a neutrophil-macrophage interaction in AS progression, and indicate that NETs represent as a novel therapeutic target in treatment of AS and other cardiovascular diseases (CVD).
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http://dx.doi.org/10.1080/15384101.2019.1662678DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6791689PMC
November 2019

Potential Regulation Mechanisms of P-gp in the Blood-Brain Barrier in Hypoxia.

Curr Pharm Des 2019 ;25(10):1041-1051

School of Pharmacy, Lanzhou University, Lanzhou, China.

The blood-brain barrier (BBB) is a barrier of the central nervous system (CNS), which can restrict the free exchange of substances, such as toxins and drugs, between cerebral interstitial fluid and blood, keeping the relative physiological stabilization. The brain capillary endothelial cells, one of the structures of the BBB, have a variety of ATP-binding cassette transporters (ABC transporters), among which the most widely investigated is Pglycoprotein (P-gp) that can efflux numerous substances out of the brain. The expression and activity of P-gp are regulated by various signal pathways, including tumor necrosis factor-α (TNF-α)/protein kinase C-β (PKC- β)/sphingosine-1-phosphate receptor 1 (S1P), vascular endothelial growth factor (VEGF)/Src kinase, etc. However, it remains unclear how hypoxic signaling pathways regulate the expression and activity of P-gp in brain microvascular endothelial cells. According to previous research, hypoxia affects the expression and activity of the transporter. If the transporter is up-regulated, some drugs enter the brain's endothelial cells and are pumped back into the blood by transporters such as P-gp before they enter the brain tissue, consequently influencing the drug delivery in CNS; if the transporter is down-regulated, the centrally toxic drug would enter the brain tissue and cause serious adverse reactions. Therefore, studying the mechanism of hypoxia-regulating P-gp can provide an important reference for the treatment of CNS diseases with a hypoxia/reoxygenation (H/R) component. This article summarized the mechanism of regulation of P-gp in BBB in normoxia and explored that of hypoxia.
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http://dx.doi.org/10.2174/1381612825666190610140153DOI Listing
February 2020

Mitotic motor CENP-E cooperates with PRC1 in temporal control of central spindle assembly.

J Mol Cell Biol 2020 08;12(8):654-665

MOE Key Laboratory for Cellular Dynamics & Anhui Key Laboratory for Chemical Biology, CAS Center for Excellence in Molecular Cell Science, Hefei National Science Center for Physical Sciences at Microscale & University of Science and Technology of China, Hefei 230027, China.

Error-free cell division depends on the accurate assembly of the spindle midzone from dynamic spindle microtubules to ensure chromatid segregation during metaphase-anaphase transition. However, the mechanism underlying the key transition from the mitotic spindle to central spindle before anaphase onset remains elusive. Given the prevalence of chromosome instability phenotype in gastric tumorigenesis, we developed a strategy to model context-dependent cell division using a combination of light sheet microscope and 3D gastric organoids. Light sheet microscopic image analyses of 3D organoids showed that CENP-E inhibited cells undergoing aberrant metaphase-anaphase transition and exhibiting chromosome segregation errors during mitosis. High-resolution real-time imaging analyses of 2D cell culture revealed that CENP-E inhibited cells undergoing central spindle splitting and chromosome instability phenotype. Using biotinylated syntelin as an affinity matrix, we found that CENP-E forms a complex with PRC1 in mitotic cells. Chemical inhibition of CENP-E in metaphase by syntelin prevented accurate central spindle assembly by perturbing temporal assembly of PRC1 to the midzone. Thus, CENP-E-mediated PRC1 assembly to the central spindle constitutes a temporal switch to organize dynamic kinetochore microtubules into stable midzone arrays. These findings reveal a previously uncharacterized role of CENP-E in temporal control of central spindle assembly. Since CENP-E is absent from yeast, we reasoned that metazoans evolved an elaborate central spindle organization machinery to ensure accurate sister chromatid segregation during anaphase and cytokinesis.
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http://dx.doi.org/10.1093/jmcb/mjz051DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7683015PMC
August 2020

Stilbenoids and cannabinoids from the leaves of Cannabis sativa f. sativa with potential reverse cholesterol transport activity.

Food Funct 2018 Dec;9(12):6608-6617

College of Chemical Engineering, Department of Pharmaceutical Engineering, Northwest University, Taibai North Road 229, Xi'an, Shaanxi 710069, China.

Three new stilbenoids (1-3) and 16 known stilbenoids (4-6) and cannabinoids (7-19) were isolated from the leaves of hemp (Cannabis sativa L.). The structures of the three new compounds were identified as α,α'-dihydro-3',4,5'-trihydroxy-4'-methoxy-3-isopentenylstilbene (HM1), α,α'-dihydro-3,4',5-trihydroxy-4-methoxy-2,6-diisopentenylstilbene (HM2), and α,α'-dihydro-3',4,5'-trihydroxy-4'-methoxy-2',3-diisopentenylstilbene (HM3) by 1D and 2D NMR spectroscopy, LC-MS, and HRESIMS. The known α,α'-dihydro-3,4',5-trihydroxy-4,5'-diisopentenylstilbene (5) and combretastatin B-2 (6) were isolated for the first time from C. sativa f. sativa. These isolated compounds exhibited cytotoxic effects on human cancer cells via inhibiting the proliferation of cancer cells and inducing cell death. Among them, compounds 4, 5, 10, 12, 13, 15, and 19 displayed broad-spectrum cytotoxicity, and 1, 7, and 11 displayed selectivity in inhibition efficiency on MCF-7 and A549 cells, which suppressed the proliferation of cancer cells significantly by inducing cell death. The effects of compounds 1-3 on improving reverse cholesterol transport (RCT) were evaluated by isotope-tracing and western blotting. Results showed that the three stilbenoids showed a cytotoxicity above 1.0 mg L-1, especially that of HM3. They could improve [3H]-cholesterol efflux from Raw 264.7 macrophages to high density lipoproteins by enhancing the protein expression of ABCG1 and SR-B1, and HM1 and HM2 showed a significant difference compared with fenofibrate at 1.0 mg L-1. The three stilbenoids could also significantly improve the protein expression of ABCA1. Further study on HepG2 cells indicated that they improve the protein expression of LDLR, SR-B1 and CYP7A1, especially that of HM1 and HM3. However, they showed no significant effect on PCSK9. The above results indicated that these stilbenoids may elevate the transfer of cholesterol to hepatocytes by improving the protein expression of SR-B1 and LDLR, and the synthesis of bile acid by increasing the protein expression of CYP7A1. In conclusion, HM1 showed lower cytotoxicity and higher activity in improving the RCT-related protein expression. Our study suggests that it may be explored as a novel lipid-lowering drug and as a beneficial ingredient in health functional foods and pharmaceuticals.
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http://dx.doi.org/10.1039/c8fo01896kDOI Listing
December 2018

Excessive outlier removal may result in cut points that are not suitable for immunogenicity assessments.

J Immunol Methods 2018 12 9;463:105-111. Epub 2018 Oct 9.

MedImmune LLC, One MedImmune Way, Gaithersburg, MD 20878, United States.

Cut point determination is an important aspect of immunogenicity assay development. The cut point can be influenced by a myriad of factors. Key among those is the analytical variability of the assay itself and biological variation due to test samples. Since a smaller cut point value may result in improved sensitivity, the existing procedures often employ statistical techniques such as outlier removal to produce a conservative cut point. Although such practices are intended to yield acceptable assay sensitivity, they may fail to fully account for biological variability in the data, thus generating higher than expected number of false positive results. In this paper, we introduce the concept of minimum cut point. It is defined as the cut point that is determined in the absence of biological variability. Under the log-normal assumption of the data used for cut point analysis, closed-form formulas are derived for the minimum cut point. This minimum cut point can be used to benchmark whether a cut point derived from a procedure can compromise assay specificity by being too low.
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http://dx.doi.org/10.1016/j.jim.2018.10.001DOI Listing
December 2018

Association of Difference in Coronary Sinus Diameter by Computed Tomographic Angiography Between Patients in and Not in Stable Atherosclerotic Plaque(S).

Med Sci Monit 2018 May 18;24:3265-3273. Epub 2018 May 18.

Department of Radiology, Beijing Luhe Hospital, Capital Medical University, Beijing, China (mainland).

BACKGROUND Pathological finding fail to describe the morphology of coronary arterial plaques. Retrograde cardiac arteriography is a complicated procedure and does not detect all left posterior and marginal veins of the heart. Magnetic resonance angiography has long scan time and low spatial resolution. The objective of the present study was to assess the possible utility of the difference in coronary sinus diameter to quantify stable atherosclerotic plaque(s) using 256-slice coronary computed tomographic angiography. MATERIAL AND METHODS A total of 336 patients were divided into 2 groups with 168 patients each. Patients who had heart failure were included in the study group and those who did not were included in the non-study group. Patients were subjected to cross-sectional study. Cardiovascular images were performed with 256-slice coronary computed tomographic angiography with a prospective electrocardiogram and clinical manifestation. Two-tailed paired t test following Dunnett's multiple comparison tests was performed for the quantitative measurement of coronary computed tomographic angiography and clinical manifestation at 99% confidence level. RESULTS The clinical manifestation did not clearly show cardiac abnormality. The diameters of the superoinferior coronary sinus ostium was than that of the anteroposterior coronary sinus ostium, (p<0.0001, q=26.325). There was the difference in size of the coronary sinus ostium between patients in and not in heart failure (p<0.0001). The study group patients had longer coronary sinuses than patients in the non-study group (p<0.0001). CONCLUSIONS 256-slice computed tomographic angiography is a feasible and is non-invasive bio-tool for evaluation of coronary artery anatomy.
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http://dx.doi.org/10.12659/MSM.907934DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5987609PMC
May 2018

Low-dose IL-2 expands CD4 regulatory T cells with a suppressive function in vitro via the STAT5-dependent pathway in patients with chronic kidney diseases.

Ren Fail 2018 Nov;40(1):280-288

a The Kidney Disease Research Center , Jingdong Yumei Kidney Disease Hospital , Beijing , China.

Background: Patients with chronic kidney disease (CKD) often have CD4+ regulatory T cells (Tregs) dysfunction and chronic inflammation. We aim to investigate the effect, function, and related mechanism of low-dose IL-2 on CD4 regulatory T cells expansion in vitro from patients with CKD.

Methods: A total of 148 newly diagnosed patients with CKD at Stage III and 35 healthy volunteer subjects were recruited into our studies. The number of peripheral Tregs in peripheral blood mononuclear cells isolated from CKD patients, which were characterized by FACS as CD4CD25 and CD4CD25FoxP3. The effect of low-dose IL-2 on expansion of Tregs, and the suppressive function of expanded Tregs were also analyzed by FACS. The levels of FoxP3 mRNA were detected by qRT-PCR. The activation of IL-2 induced Stat5 and blocking experiments were assessed by Western Blotting and FACS.

Results: We found that the frequency of peripheral Tregs from CKD patients was significantly lower than that in healthy volunteer subjects. We also showed that IL-2 selectively expanded CD4CD25 and CD4CD25FoxP3 regulatory T cells, and also upregulated the expression of FoxP3 mRNA. Our in vitro studies demonstrated that expanded CD4 regulatory T cells from CKD patients suppressed proinflammatory Th1 and Th17 cell response. Furthermore, STAT5 activation is required for IL-2-induced expansion of regulatory T cells and expression of FoxP3 mRNA from CKD patients.

Conclusions: Our findings support the clinical Treg defects in CKD patients with glomerular diseases, and the rationale of evaluating low-dose IL-2 treatment for selectively modulating CD4 Tregs.
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http://dx.doi.org/10.1080/0886022X.2018.1456462DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6014482PMC
November 2018

Passivation Characteristics of Alloy Corrosion-Resistant Steel Cr10Mo1 in Simulating Concrete Pore Solutions: Combination Effects of pH and Chloride.

Materials (Basel) 2016 Sep 1;9(9). Epub 2016 Sep 1.

School of Materials Science and Engineering, Southeast University, Nanjing 211189, Jiangsu, China.

The electrochemical behaviour for passivation of new alloy corrosion-resistant steel Cr10Mo1 immersed in alkaline solutions with different pH values (13.3, 12.0, 10.5, and 9.0) and chloride contents (0.2 M and 1.0 M), was investigated by various electrochemical techniques: linear polarization resistance, electrochemical impedance spectroscopy and capacitance measurements. The chemical composition and structure of passive films were determined by XPS. The morphological features and surface composition of the immersed steel were evaluated by SEM together with EDS chemical analysis. The results evidence that pH plays an important role in the passivation of the corrosion-resistant steel and the effect is highly dependent upon the chloride contents. In solutions with low chloride (0.2 M), the corrosion-resistant steel has notably enhanced passivity with pH falling from 13.3 to 9.0, but does conversely when in presence of high chloride (1.0 M). The passive film on the corrosion-resistant steel presents a bilayer structure: an outer layer enriched in Fe oxides and hydroxides, and an inner layer, rich in Cr species. The film composition varies with pH values and chloride contents. As the pH drops, more Cr oxides are enriched in the film while Fe oxides gradually decompose. Increasing chloride promotes Cr oxides and Fe oxides to transform into their hydroxides with little protection, and this is more significant at lower pH (10.5 and 9.0). These changes annotate passivation characteristics of the corrosion-resistant steel in the solutions of different electrolyte.
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http://dx.doi.org/10.3390/ma9090749DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5457108PMC
September 2016

Immunogenicity assay cut point determination using nonparametric tolerance limit.

J Immunol Methods 2017 03 5;442:29-34. Epub 2017 Jan 5.

MedImmune LLC, Gaithersburg, MD, United States. Electronic address:

The newly released FDA guidance on immunogenicity assay development and validation recommends use of a lower confidence limit of the percentile of the negative subject population as the cut point in order to guarantee a pre-specified false positive rate with high confidence. The limit is, in essence, a lower tolerance limit. Although in literature several methods are available for determining the tolerance limit, they either fail to take into account the repeated measurement of the data from a typical immunogenicity assay quantification/validation experiment or rely heavily on normality assumption of the data, which is rarely correct. As a result, the methods may result in biased estimates of the cut point, causing the false positive rate to be either lower or higher than expected. To overcome this drawback, we propose two non-parametric methods under repeated measure data structure and without normal distribution assumption. Simulation studies were carried to compare the performance of the two non-parametric approaches with the current methods. The results of the simulation studies show that one of the two nonparametric methods outperforms all the other methods and provides a satisfactory coverage probability even with moderate sample sizes. In addition, it is simple and straightforward to implement. Therefore, it is a preferred method for immunogenicity assay cut point determination.
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http://dx.doi.org/10.1016/j.jim.2017.01.001DOI Listing
March 2017

Chemotherapeutic drug selectivity between wild-type and mutant BRaf kinases in colon cancer.

J Mol Model 2017 Jan 5;23(1). Epub 2016 Dec 5.

Department of Gastroenterology, Linyi People's Hospital, Linyi, 276003, China.

Oncogenic BRaf V600E mutation is involved in the development, invasion and metastasis of colon cancer. Selective inhibition of BRaf mutant has been recognized as a therapeutic strategy for the cancer. Here, we carried out atomistic molecular dynamics (MD) simulations to characterize the structural basis, energetic property, and dynamics behavior of conformational change in BRaf activation loop upon the mutation. It is found that V600E mutation destabilizes inactive DFG-out conformation of activation loop and promotes its conversion to the active DFG-in conformation, thus conferring constitutive activity for BRaf kinase. A further analysis revealed that the conformational change is induced by electrostatic effect of the negatively charged mutant residue Glu600, which can form a potent salt bridge with the positively charged residue Lys570; this is naturally consistent with phosphorylation of activation loop to activate the kinase. Both of them introduce a negative charge to activation loop and, consequently, the DFG-out is destabilized and conversed to DFG-in. Energetic analysis unraveled that small-molecule kinase inhibitor PLX4720 has a similar selectivity profile for mutant over wild-type kinases and for phosphorylated and dephosphorylated kinases. This can be substantiated in part by in vitro kinase assay that the inhibitor exhibits 12.6 and 10.4-fold higher potencies against mutant than wild type and against phosphorylated than dephosphorylated, respectively. It is suggested that the activation loop conformation, but neither V600E mutation nor phosphorylation, directly determines inhibitor affinity; the mutation and phosphorylation can only indirectly influence inhibitor binding via regulation of activation loop conformation. Graphical Abstract Chemotherapeutic drug selectivity between wild-type and mutant BRaf kinases in colon cancerᅟ.
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http://dx.doi.org/10.1007/s00894-016-3177-8DOI Listing
January 2017

Serum A08 C1q antibodies are associated with disease activity and prognosis in Chinese patients with lupus nephritis.

Kidney Int 2016 12 10;90(6):1357-1367. Epub 2016 Oct 10.

Renal Division, Department of Medicine, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China and Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, PR China; Peking-Tsinghua Center for Life Sciences, Beijing, PR China.

Systemic lupus erythematosus (SLE) is an autoimmune disease characterized by overproduction of numerous autoantibodies. Many studies have sought to identify such biomarkers to distinguish patients with active lupus nephritis from SLE patients without renal involvement. Because antibodies to complement C1q appear to be prevalent in patients with active lupus nephritis, we analyzed the frequency of antigenic epitopes of C1q and their clinical significance in a large multicenter study of Chinese patients. The lupus cohort consisted of 210 patients with active lupus nephritis as a discovery cohort, 130 active patients as a validation cohort along with 130 SLE patients without clinical renal involvement, and 100 healthy controls. Serum antibodies to intact C1q, the collagen-like region, the globular head region, and the new linear A08 epitope to C1q were screened by specific ELISA. The frequency of antibodies to intact C1q, the C1q-collagen-like region, and the A08 antibodies in the discovery cohort were significantly higher than that in patients without renal involvement or healthy controls. Antibodies to the globular head region were not prevalent enough for further study. The results were confirmed in the validation cohort. The area under the curve for anti-A08 antibodies was significantly greater than those for both the intact and collagen-like region antibodies to discriminate between active lupus nephritis and active SLE without clinical renal involvement. The A08 antibodies were all negative at remission. The serum A08 antibody level correlated better with disease relapse than that of antibodies to either the intact or the collagen-like region, significantly predicting renal prognosis. Thus, serum levels of A08 C1q antibodies are closely associated with disease activity and prognosis in lupus nephritis.
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http://dx.doi.org/10.1016/j.kint.2016.08.010DOI Listing
December 2016

A Sputum Proteomic Signature That Associates with Increased IL-1β Levels and Bacterial Exacerbations of COPD.

Lung 2016 06 15;194(3):363-9. Epub 2016 Apr 15.

VA WNY Healthcare System and University at Buffalo, State University of New York, Buffalo, NY, USA.

Purpose: Activation of the interleukin-1β (IL-1β) signaling pathway has been implicated in COPD, but the proportion of COPD subjects whose disease is principally driven by activation of this pathway is poorly understood. In this study, we sought to differentiate an IL-1β-associated sputum signature from other inflammation-associated COPD phenotypes.

Methods: Luminex-multiplex assays were used to study IL-1β-mediated signature proteins within airway epithelium, smooth muscle, and vascular endothelial cell cultures. The IL-1β-mediated signature was tested in a longitudinal study comprising of 35 paired stable-COPD and acute exacerbation (AECOPD) sputum samples. The presence of respiratory pathogens (H. influenzae, M. catarrhalis, S. pneumoniae, and P. aeruginosa) was evaluated by sputum cultures.

Results: Five proteins namely TNF-α, GCSF, IL-6, CD-40L, and MIP-1β were found to be IL-1β-regulated across all donors and cell types. All five of these IL-1β-mediated proteins were significantly increased (p < 0.05) in sputum corresponding to AECOPD events showing at least a twofold increase in IL-1β (IL-1β(+) events, 18 of 35 total events), relative to preceding stable-COPD state. Sputum IL-1β levels showed no significant association (p > 0.05, spearman) with known markers of other major COPD inflammation phenotypes. In addition, there was a significant association with bacterial presence in sputum culture with an odds ratio of 9 (95 % CI 1.56, 51.9) in IL-1β(+) events versus IL-1β(-) events.

Conclusion: Our findings provide insights into potential markers of IL-1β-associated AECOPD, and reaffirm association between IL-1β pathway activation and airway bacterial infection in COPD. Taken together, our findings could help identify COPD patient subsets who may benefit from therapies targeting IL-1β pathway.
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http://dx.doi.org/10.1007/s00408-016-9877-0DOI Listing
June 2016

The Effects of Indoxyl Sulfate on Human Umbilical Cord-Derived Mesenchymal Stem Cells In Vitro.

Cell Physiol Biochem 2016 29;38(1):401-14. Epub 2016 Jan 29.

The Kidney Disease Research Center, Jingdong Yumei Kidney Disease Hospital, Beijing, China.

Background/aims: Indoxyl sulfate, an important protein-bound uremic toxin, can damage stem cells, thus hampering stem cell-based regenerative medicine approaches targeting chronic kidney diseases (CKD). Human umbilical cord-derived mesenchymal stem cells (hUC-MSCs) are thought to have promising clinical application because of their high proliferative potential and ease of isolation than MSCs from other sources. In the present study, we aimed to determine the harmful effects of indoxyl sulfate on the phenotype and functional potential of hUC-MSCs in vitro.

Methods: The toxicity and cell viability was examined by Trypan blue exclusion and MTT assay. The cellular surface markers and the percentage of apoptotic cells by Annexin-V/PI staining were analyzed by flow cytometry. Proliferation was evaluated based on cell number counting and Ki-67 immunostaining. Cell senescence was measured using senescence-associated β-Galactosidase activity. The ability to stimulate the development of CD4+CD25+FoxP3+ regulatory T cells was assessed by incubating hUC-MSCs with peripheral blood mononuclear cells from the healthy volunteers.

Results: Our results demonstrated that the immunophenotype of hUC-MSCs was not affected by indoxyl sulfate flow cytometry. However, a significant decrease in cell numbers and fraction of Ki-67 positive proliferating cells, along with a significant increase in cellular senescence were detected in hUC-MSCs after exposure to indoxyl sulfate. Additionally, their ability to stimulate CD4+CD25+FoxP3+ regulatory T cell production was compromised when hUC-MSCs were pretreated with indoxyl sulfate.

Conclusion: Taken together, our study clearly demonstrated that the molecular alterations and functional incompetence in hUC-MSCs under the challenge of indoxyl sulfate in vitro.
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http://dx.doi.org/10.1159/000438639DOI Listing
October 2016

Pentraxin 3 Is Closely Associated With Tubulointerstitial Injury in Lupus Nephritis: A Large Multicenter Cross-Sectional Study.

Medicine (Baltimore) 2016 Jan;95(3):e2520

From the Renal Division, Department of Medicine, Peking University First Hospital, Beijing, P.R. China (YP, YT, FY, M-HZ); Institute of Nephrology, Peking University, Beijing, P.R. China (YP, YT, FY, M-HZ); Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, P.R. China (YP, YT, FY, M-HZ); Key Laboratory of CKD Prevention and Treatment, Ministry of Education of China, Beijing, P.R. China (YP, YT, FY, M-HZ); Department of Rheumatology and Clinical Immunology, Peking Union Medical College Hospital, Beijing, P.R. China (YL); Chinese Academy of Medical Sciences & Peking Union Medical College, Beijing, P.R. China (YL); Key Laboratory of Rheumatology and Clinical Immunology, Ministry of Education, Beijing, P.R. China (YL); Renal Division, Jing Dong Yu Mei Traditional Chinese Medicine and Western Medicine Integrative Kidney Disease Hospital, Hebei, P.R. China (JZ); Department of Nephrology, Anyang District Hospital, Henan, P.R. China (YG); Department of Nephrology, First Affiliated Hospital of Henan University of Science and Technology, Henan, P.R. China (ZG); Department of Nephrology, Beijing General Hospital of Armed Police Forces, Beijing, P.R. China (CZ); Department of Nephrology, Peking University International Hospital, Beijing, P.R. China (FY); and Peking-Tsinghua Center for Life Sciences, Beijing, P.R. China ( M-HZ).

Lupus nephritis always elicits immune inflammatory tissue damages in kidney. Pentraxin 3 (PTX3), mainly produced at inflammatory sites, is known to be involved in the regulation of the innate immunity system. The aim of this study was to investigate the serum and urine levels of PTX3, and the expression of PTX3 in renal tissues in lupus nephritis patients from a large Chinese cohort.The study used cross-sectional survey and 288 active lupus nephritis patients, including discovery cohort and validation cohort, 115 systemic lupus erythematosus (SLE) patients without clinical renal involvement and 46 healthy controls were enrolled. Serum and urine PTX3 were screened by enzyme-linked immunosorbent assay (ELISA). The renal deposition of PTX3 was detected by immunohistochemistry and immunofluorescence.The average level of serum PTX3 in the discovery cohort of lupus nephritis was significantly higher than that in nonrenal involvement SLE group and normal controls (P < 0.001, P < 0.001, respectively), which was confirmed by the validation cohort. Serum PTX3 levels of 15 lupus nephritis patients in remission decreased significantly compared with that in active phase. Serum PTX3 levels were significantly higher in patients with hematuria (P = 0.014), leucocyturia (P = 0.002), acute renal failure (P = 0.001), and nephrotic syndrome (P = 0.036). There were significant correlations between serum PTX3 levels and Systemic Lupus Erythematosus Disease Activity Index (SLEDAI) scores, serum creatinine value, renal pathological activity indices, and serum complement 3 (C3) in active lupus nephritis patients. The urinary PTX3 levels were significantly higher in active lupus nephritis patients compared with patients in remission and normal controls (P = 0.011, P = 0.008, respectively). There were significant associations between urinary PTX3 levels and multiple indices of tubulointerstitial lesions, including urinary KIM-1 (r = 0.368, P = 0.016), neutrophil gelatinase-associated lipocalin (NGAL) (r = 0.320, P = 0.039), microalbumin (r = 0.621, P = 0.003), transferring (r = 0.451, P = 0.040) levels and renal pathological indices scores, especially interstitial inflammation (r = 0.349, P = 0.025) in active lupus nephritis patients. A significant correlation was found between serum and urine PTX3 levels (r = 0.431, P = 0.006). PTX3 staining was mainly observed in tubulointerstitial areas of patients with lupus nephritis, and immunofluorescence study showed that PTX3 could colocalize with fibroblast in interstitium.Circulating and local PTX3 levels were significantly increased in patients with active lupus nephritis and might be a biomarker for the disease progression, especially of tubulointerstitial injury.
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http://dx.doi.org/10.1097/MD.0000000000002520DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4998266PMC
January 2016

A Bayesian Approach to Residual Host Cell DNA Safety Assessment.

PDA J Pharm Sci Technol 2016 Mar-Apr;70(2):157-62. Epub 2016 Jan 21.

MedImmune LLC, Gaithersburg, MD.

Unlabelled: Biological medicinal products inevitably contain residual DNA from host cells. Therefore, there is a theoretical possibility that cellular DNA in a medicinal product may cause oncogenic or infective events. Over the past decades, quantification of such risk has been the subject of intense scientific and regulatory interest. While several methods have been proposed in the literature, they are primarily concerned with point estimation of the oncogenic and infective risk. In this article, we propose a full Bayesian procedure to assess the safety risk. Safety risk is redefined as the posterior probability for the safety factor to be above an acceptable limit. The formulation of the problem in the Bayesian framework makes it possible to incorporate the uncertainties of key parameters into the safety risk assessment. It also allows for taking full use of prior knowledge of the risk associated with residual DNA and the understanding of DNA removal process. As a result, the method not only provides a more accurate estimation of oncogenicity or infectivity risk but also a probabilistic interpretation of the risk estimation.

Lay Abstract: Medicines produced from biological sources like cells can contain DNA. It is not clear what health risk the DNA can pose to the product recipients, but often it can be designed to minimize the risk by reducing the levels of DNA during manufacture. This article characterizes residual DNA risk in terms of probability, and a Bayesian approach to assessing the health risk is proposed.
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http://dx.doi.org/10.5731/pdajpst.2015.006296DOI Listing
January 2018

A Generalized Pivotal Quantity Approach to Analytical Method Validation Based on Total Error.

PDA J Pharm Sci Technol 2015 Nov-Dec;69(6):725-35

MedImmune, LLC.

Unlabelled: The primary purpose of method validation is to demonstrate that the method is fit for its intended use. Traditionally, an analytical method is deemed valid if its performance characteristics such as accuracy and precision are shown to meet prespecified acceptance criteria. However, these acceptance criteria are not directly related to the method's intended purpose, which is usually a gurantee that a high percentage of the test results of future samples will be close to their true values. Alternate "fit for purpose" acceptance criteria based on the concept of total error have been increasingly used. Such criteria allow for assessing method validity, taking into account the relationship between accuracy and precision. Although several statistical test methods have been proposed in literature to test the "fit for purpose" hypothesis, the majority of the methods are not designed to protect the risk of accepting unsuitable methods, thus having the potential to cause uncontrolled consumer's risk. In this paper, we propose a test method based on generalized pivotal quantity inference. Through simulation studies, the performance of the method is compared to five existing approaches. The results show that both the new method and the method based on β-content tolerance interval with a confidence level of 90%, hereafter referred to as the β-content (0.9) method, control Type I error and thus consumer's risk, while the other existing methods do not. It is further demonstrated that the generalized pivotal quantity method is less conservative than the β-content (0.9) method when the analytical methods are biased, whereas it is more conservative when the analytical methods are unbiased. Therefore, selection of either the generalized pivotal quantity or β-content (0.9) method for an analytical method validation depends on the accuracy of the analytical method. It is also shown that the generalized pivotal quantity method has better asymptotic properties than all of the current methods.

Lay Abstract: Analytical methods are often used to ensure safety, efficacy, and quality of medicinal products. According to government regulations and regulatory guidelines, these methods need to be validated through well-designed studies to minimize the risk of accepting unsuitable methods. This article describes a novel statistical test for analytical method validation, which provides better protection for the risk of accepting unsuitable analytical methods.
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http://dx.doi.org/10.5731/pdajpst.2015.01081DOI Listing
January 2018

HIV-1 prevalence and subtype/recombinant distribution among travelers entering China from Vietnam at the HeKou port in the Yunnan province, China, between 2003 and 2012.

J Med Virol 2015 Sep 10;87(9):1500-9. Epub 2015 Apr 10.

Faculty of Life Science and Technology, Center for Molecular Medicine in Yunnan province, Kunming University of Science and Technology, Yunnan, China.

The aim of this study was to assess HIV-1 prevalence and the distribution of HIV-1 subtypes among travelers crossing the border at the HeKou land port. Between 2003 and 2012, 22,799 persons were randomly recruited from people entering China from Vietnam. In this crossing border population, a total of 161 (0.71%) travelers were determined as HIV-1-positive. From them, 140 HIV-1-positive serum samples were collected for RNA extraction and subsequent RT-nested PCR amplification of the group-specific antigen (gag)-RT with a length of 2.6 kb. The DNA sequences were analyzed to determine the HIV-1 subtypes/recombinants. We found that the circulating recombinant form 01_AE (CRF01_AE) was the most common HIV-1 subtype, accounting for 49.4% (41/83) of the subtyped 83 samples, followed by CRF08_BC (26.5%, 22/83) and CRF07_BC (7.2%, 6/83). Only 1 sample was classified as subtype C. Thirteen cases could not be clustered into any known subtypes or CRFs and presented as unique recombinant forms (URFs). Of them, 6 recombination patterns were identified. They had distinct structures consisting of fragments of subtypes B, C, CRF01_AE, CRF07_BC and CRF08_BC. Between 2003 and 2012, CRF01_AE and CRE08_BC were shown to be the most prevalent recombinant forms identified each year. But yearly change of each subtype is uncertain regular among in these travelers during the past decade. Understanding the distribution of HIV-1 subtypes/recombinants and how it changes across time among individuals entering China from Vietnam through this land port is crucial to establish strategies for the prevention of HIV cross-border transmission.
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http://dx.doi.org/10.1002/jmv.24202DOI Listing
September 2015

Non-normal random effects models for immunogenicity assay cut point determination.

J Biopharm Stat 2015 ;25(2):295-306

a MedImmune LLC , Gaithersburg , Maryland , USA.

Administration of biological therapeutics can generate undesirable immune responses that may induce anti-drug antibodies (ADAs). Immunogenicity can negatively affect patients, ranging from mild reactive effect to hypersensitivity reactions or even serious autoimmune diseases. Assessment of immunogenicity is critical as the ADAs can adversely impact the efficacy and safety of the drug products. Well-developed and validated immunogenicity assays are required by the regulatory agencies as tools for immunogenicity assessment. Key to the development and validation of an immunogenicity assay is the determination of a cut point, which serves as the threshold for classifying patients as ADA positive(reactive) or negative. In practice, the cut point is determined as either the quantile of a parametric or nonparametric empirical distribution. The parametric method, which is often based on a normality assumption, may lead to biased cut point estimates when the normality assumption is violated. The non-parametric method, which yields unbiased estimates of the cut point, may have low efficiency when the sample size is small. As the distribution of immune responses are often skewed and sometimes heavy-tailed, we propose two non-normal random effects models for cut point determination. The random effects, following a skew-t or log-gamma distribution, can incorporate the skewed and heavy-tailed responses and the correlation among repeated measurements. Simulation study is conducted to compare the proposed method with the current normal and nonparametric alternatives. The proposed models are also applied to a real dataset generated from assay validation studies.
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http://dx.doi.org/10.1080/10543406.2014.972515DOI Listing
July 2015

Preparation and antibacterial property of silver-containing mesoporous 58S bioactive glass.

Mater Sci Eng C Mater Biol Appl 2014 Sep 11;42:22-30. Epub 2014 May 11.

The Quartermaster Research Institute of the General Logistic Department of CPLA, Beijing 100082, China.

The modified mesoporous 58S bioglass (SM58S) was prepared through surface modification of the mesoporous 58S bioglass (M58S) with γ-aminopropyl triethoxysilane (KH550). The results of Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) showed that the amino groups were grafted to the surface of M58S after modification with KH550. The silver-containing SM58S (Ag-SM58S) and M58S (Ag-M58S) were prepared by the dipping method. The Ag(+) loading capacity, release rate and antibacterial properties of Ag-SM58S and Ag-M58S were investigated. It is indicated that surface modification of M58S with KH550 can improve the Ag(+) loading capacity. The result of antibacterial property showed that Ag-SM58S exhibited significant anti-bacterial effects against Escherichia coli and Staphylococcus aureus. The sustained release of Ag(+) from Ag-SM58S for 768h ensured excellent antibacterial property of Ag-SM58S. In vitro osteoblast proliferation and differentiation tests showed that Ag-SM58S was a good matrix for the growth of osteoblasts. Consequently, the results of the study suggested that Ag-SM58S might be a promising bone repair material.
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http://dx.doi.org/10.1016/j.msec.2014.05.004DOI Listing
September 2014

LC-MS/MS method for the simultaneous determination of PA-824, moxifloxacin and pyrazinamide in rat plasma and its application to pharmacokinetic study.

J Pharm Biomed Anal 2014 Aug 5;97:1-8. Epub 2014 Apr 5.

Department of Medicinal Chemistry, School of Pharmacy, The Fourth Military Medical University, Xi'an 710032, China.

A simple, sensitive and rapid LC-MS/MS method has been developed and validated for simultaneous determination of PA-824, moxifloxacin, and pyrazinamide in rat plasma using metronidazole as internal standard. Sample preparation involved a simple one-step protein precipitation with methanol, followed by centrifugation and evaporation of the organic solvent. The residue was redissolved in mobile phase and analyzed by LC-MS/MS. An Inertsil(®) ODS3 C18 column (150mm×4.6mm, 5μm), a mobile phase composed of methanol-0.03% TEA (triethylamine) in water (85:15, v/v), and a flow rate of 0.5mL/min were employed, and the total run time was 6.0min. The mass spectrometer was run in positive ion ESI-APCI combined mode using multiple reaction monitoring (MRM) to monitor the mass transitions. The method was validated for accuracy, precision, linearity, range, selectivity, lower limit of quantification (LLOQ), recovery, and matrix effect. All validation parameters met the acceptance criteria according to regulatory guidelines. The LLOQ was 1.0μg/mL for pyrazinamide and 0.1μg/mL for PA-824 and moxifloxacin. The recoveries obtained for PA-824, moxifloxacin and pyrazinamide were ≥85%. Intra-day and inter-day coefficients of variation were less than 10%. The method had been successfully applied to a pharmacokinetic study of fixed dose administration of PA-824, moxifloxacin, pyrazinamide and their combination in SD rat. Significant differences of Tmax, Cmax, AUC(0-t) and CLz/F were observed between the single and combined groups after equal dose of PA-824 and moxifloxacin administration, which revealed the possibility of drug-drug interaction (DDI) between the PaMZ combination.
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http://dx.doi.org/10.1016/j.jpba.2014.03.046DOI Listing
August 2014

Sample size consideration for immunoassay screening cut-point determination.

J Biopharm Stat 2014 ;24(3):535-45

a MedImmune LLC , Gaithersburg , Maryland , USA.

Past decades have seen a rapid growth of biopharmaceutical products on the market. The administration of such large molecules can generate antidrug antibodies that can induce unwanted immune reactions in the recipients. Assessment of immunogenicity is required by regulatory agencies in clinical and nonclinical development, and this demands a well-validated assay. One of the important performance characteristics during assay validation is the cut point, which serves as a threshold between positive and negative samples. To precisely determine the cut point, a sufficiently large data set is often needed. However, there is no guideline other than some rule-of-thumb recommendations for sample size requirement in immunoassays. In this article, we propose a systematic approach to sample size determination for immunoassays and provide tables that facilitate its applications by scientists.
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http://dx.doi.org/10.1080/10543406.2014.889921DOI Listing
December 2014

Determination of pork spoilage by colorimetric gas sensor array based on natural pigments.

Food Chem 2014 Feb 4;145:549-54. Epub 2013 Sep 4.

School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Rd., 212013 Zhenjiang, Jiangsu, China.

A new colorimetric gas-sensor array based on four natural pigments, that were extracted from spinach (Spinacia oleracea), red radish (Raphanus sativus L.), winter jasmine (Jasminum nudiflorum), and black rice (Oryza sativa L. indica), was developed for pork freshness evaluation. A colour change profile for each sample was obtained by differentiating the images of the sensor array before and after exposure to the odour of sample. The total viable count (TVC) per gram of pork was obtained by classical microbiological plating methods, and the biogenic amines were measured by HPLC. Biogenic amine index (BAI) for the determination of meat freshness was developed from the sum of putrescine and cadaverine. The colour change profiles were analysed using principal component analysis and correlated with conventional methods (BAI, TVC). A partial least squares (PLS) prediction model was obtained with r=0.854 and 0.933 for BAI and TVC, respectively.
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http://dx.doi.org/10.1016/j.foodchem.2013.08.101DOI Listing
February 2014

Prediction of outcomes in crescentic IgA nephropathy in a multicenter cohort study.

J Am Soc Nephrol 2013 Dec 12;24(12):2118-25. Epub 2013 Sep 12.

Renal Division, Peking University First Hospital, Institute of Nephrology, Peking University, Key Laboratory of Renal Disease, Ministry of Health of China, Beijing, China;

Crescentic IgA nephropathy (IgAN), defined as >50% crescentic glomeruli on kidney biopsy, is one of the most common causes of rapidly progressive GN. However, few studies have characterized this condition. To identify risk factors and develop a prediction model, we assessed data from patients ≥ 14 years old with crescentic IgAN who were followed ≥ 12 months. The discovery cohort comprised 52 patients from one kidney center, and the validation cohort comprised 61 patients from multiple centers. At biopsy, the mean serum creatinine (SCr) level ± SD was 4.3 ± 3.4 mg/dl, and the mean percentage of crescents was 66.4%± 15.8%. The kidney survival rates at years 1, 3, and 5 after biopsy were 57.4%± 4.7%, 45.8%± 5.1%, and 30.4%± 6.6%, respectively. Multivariate Cox regression revealed initial SCr as the only independent risk factor for ESRD (hazard ratio [HR], 1.32; 95% confidence interval [CI], 1.10 to 1.57; P=0.002). Notably, the percentage of crescents did not associate independently with ESRD. Logistic regression showed that the risk of ESRD at 1 year after biopsy increased rapidly at SCr>2.7 mg/dl and reached 90% at SCr>6.8 mg/dl (specificity=98.5%, sensitivity=64.6% for combined cohorts). In both cohorts, patients with SCr>6.8 mg/dl were less likely to recover from dialysis. Analyses in additional cohorts revealed a similar association between initial SCr and ESRD in patients with antiglomerular basement membrane disease but not ANCA-associated systemic vasculitis. In conclusion, crescentic IgAN has a poor prognosis, and initial SCr concentration may predict kidney failure in patients with this disease.
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http://dx.doi.org/10.1681/ASN.2012101017DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3839544PMC
December 2013
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