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1.
Artigo em Inglês | MEDLINE | ID: mdl-32071230

RESUMO

Ammonia oxidation to nitrite and its subsequent oxidation to nitrate provides energy to the two populations of nitrifying chemoautotrophs in the energy-starved dark ocean, driving a coupling between reduced inorganic nitrogen (N) pools and production of new organic carbon (C) in the dark ocean. However, the relationship between the flux of new C production and the fluxes of N of the two steps of oxidation remains unclear. Here, we show that, despite orders-of-magnitude difference in cell abundances between ammonia oxidizers and nitrite oxidizers, the two populations sustain similar bulk N-oxidation rates throughout the deep waters with similarly high affinities for ammonia and nitrite under increasing substrate limitation, thus maintaining overall homeostasis in the oceanic nitrification pathway. Our observations confirm the theoretical predictions of a redox-informed ecosystem model. Using balances from this model, we suggest that consistently low ammonia and nitrite concentrations are maintained when the two populations have similarly high substrate affinities and their loss rates are proportional to their maximum growth rates. The stoichiometric relations between the fluxes of C and N indicate a threefold to fourfold higher C-fixation efficiency per mole of N oxidized by ammonia oxidizers compared to nitrite oxidizers due to nearly identical apparent energetic requirements for C fixation of the two populations. We estimate that the rate of chemoautotrophic C fixation amounts to ∼1 × 1013 to ∼2 × 1013 mol of C per year globally through the flux of ∼1 × 1014 to ∼2 × 1014 mol of N per year of the two steps of oxidation throughout the dark ocean.

2.
J Integr Med ; 2020 Feb 07.
Artigo em Inglês | MEDLINE | ID: mdl-32067923

RESUMO

Hepatocellular carcinoma (HCC) is a prevalent and highly malignant cancer throughout the world. Effective treatment of this disease is impeded by the high rate of metastasis, recurrence, and chemoresistance. Recent studies have revealed the close relationship between the malignant phenotype of HCC and cancer stem cells (CSCs). Therefore, CSC-targeted therapy is considered a promising strategy to eradicate HCC. Traditional Chinese medicine (TCM) can be effective in preventing recurrence and metastasis of some advanced HCC. A growing amount of literature has discovered that extracts or compounds derived from TCM exert an anti-CSC effect. This review introduces some formulas and chemical compounds derived from TCMs that have been reported to inhibit CSCs of HCC; these TCM-related drugs may help to provide an alternative approach to help manage cancers, especially for HCC which has a great potential of metastasis, recurrence, and chemoresistance.

3.
J Integr Plant Biol ; 2020 Feb 18.
Artigo em Inglês | MEDLINE | ID: mdl-32068336

RESUMO

A recent paper by Kidokoro et al. (2020) in The Plant Cell reported a transgene-dependent transcriptional silencing phenomenon in the dominant ice1-1 Arabidopsis mutant containing the CBF3-LUC reporter, and questioned whether ICE1 may regulate CBF genes and may be involved in plant cold response. Here, we evaluate available evidences supporting the involvement of ICE1 in plant cold response, and provide ChIP-seq data showing ICE1 binding to the promoters of CBF genes and other regulatory genes known to be critical for cold response as well as to the promoters of some COR genes. This article is protected by copyright. All rights reserved.

4.
Biomolecules ; 10(2)2020 Feb 03.
Artigo em Inglês | MEDLINE | ID: mdl-32028653

RESUMO

The role of human papillomavirus type 16 (HPV16) in oral potentially malignant disorders (OPMD) and oral cavity carcinoma (OC) is still under debate. We investigated HPV16 prevalence in unstimulated saliva, oral rinse samples, oral swabs and tumour biopsies collected from OPMD (n = 83) and OC (n = 106) patients. HPV16 genotype, viral load, physical status (episomal vs. integrated) and tumour p16INK4a expression were determined. Oral HPV16 prevalence was higher in OC than in OPMD, but this difference was not statistically significant (7.5% (8/106) versus 3.6% (3/83), odds ratio (OR): 2.18, 95% confidence interval (CI): 0.56, 8.48, p = 0.26). There was a significant association (p < 0.05) between oral HPV16 infection and heavy tobacco consumption. Real-time PCR results indicated that no integration events occurred in either OPMD or OC cases based on the HPV16 E2/E6 ratio. HPV16 positive OPMD and OC patients had similar HPV16 E2 and E6 viral loads. The inter-rater agreement between tumour p16INK4a expression and oral HPV16 infection was considered as fair (k = 0.361) for OC. Our data suggest that the involvement of HPV16 in oral carcinogenesis is limited.

5.
Biochim Biophys Acta Mol Cell Res ; 1867(5): 118676, 2020 May.
Artigo em Inglês | MEDLINE | ID: mdl-32044386

RESUMO

In egress routes of malignancy, cancer cells are constantly subjected to shear stress imposed by blood/lymph flow. Increasing evidence points toward the regulatory roles of shear stress in tumor cell adhesion and motility. Although it is known that integrin endocytic trafficking governs focal adhesion (FA) turnover and cell migration, the effect and biological consequences of low shear stress (LSS) on integrin trafficking remain unclear. Here, we identified the critical role of integrin ß1 trafficking and caveolin-1 (Cav-1) mediated endocytosis in LSS-induced cell directional migration. LSS altered the distribution of integrin ß1 in MDA-MB-231 cells and significantly promoted its internalization and recycling, which in turn facilitated FA turnover and directional cell migration. Furthermore, LSS induced cytoskeleton remodeling, which was required for internalization of integrin ß1. LSS down-regulated the acetylation level of microtubules (MTs) via activating ROCK/HDAC6 pathway, resulting in elevation of MTs dynamics, Cav-1 motility, and Cav-1-dependent integrin ß1 recycling. We also showed that high HDAC6 expression was a ROCK-dependent prognostic factor, which was correlated with poor outcomes in breast cancer patients. Taken together, these results defined a novel mechanism by which LSS enhanced integrin ß1 trafficking via actin cytoskeleton remodeling and ROCK/HDAC6 mediated deacetylation of MTs, thereby promoting FAs turnover and directional cell migration.

6.
EBioMedicine ; 52: 102626, 2020 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-31981979

RESUMO

BACKGROUND: Forkhead box protein f1 (Foxf1) is associated with cell differentiation, and may be a key player in bone homoeostasis. However, the effect of Foxf1 on osteogenesis of bone marrow-derived mesenchymal stem cells (BMSCs) and ovariectomy-induced bone loss, as well as its clinical implications, is unknown. METHODS: By quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and western blotting, we assayed Foxf1 expression in bone tissue, BMSCs, and bone marrow-derived macrophages (BMMs), derived from ovariectomised (OVX) mice, and during osteogenic differentiation and osteoclast differentiation. Using a loss-of-function approach (small interfering RNA [siRNA]-mediated knockdown) in vitro, we examined whether Foxf1 regulates osteoblast differentiation of BMSCs via the Wnt/ß-catenin signalling pathway. Furthermore, we assessed the anabolic effect of Foxf1 knockdown (siFoxf1) in OVX mice in vivo. We also assayed the expression of Foxf1 in bone tissue derived from postmenopausal osteoporosis (PMOP) patients and its link with bone mineral density (BMD). Finally, we examined the effect of Foxf1 knockdown on the osteoblastic differentiation of human BMSCs. FINDINGS: Foxf1 expression was significantly increased in bone extract and BMSCs from OVX mice and gradually decreased during osteoblastic differentiation of BMSCs but did not differ significantly in OVX mouse-derived BMMs or during osteoclast differentiation. In vitro, Foxf1 knockdown markedly increased the expression of osteoblast specific genes, alkaline phosphatase (ALP) activity, and mineralisation. Moreover, siFoxf1 activated the Wnt/ß-catenin signalling pathway. The siFoxf1-induced increase in osteogenic differentiation was partly rescued by inhibitor of Wnt signalling (DKK1). In OVX mice, Foxf1 siRNA significantly reduced bone loss by enhancing bone formation. Foxf1 expression levels negatively correlated with reduced bone mass and bone formation in bone tissue from PMOP patients. Finally, Foxf1 knockdown significantly promoted osteogenesis by human BMSCs. INTERPRETATION: Our findings indicate that Foxf1 knockdown promotes BMSC osteogenesis and prevents OVX-induced bone loss. Therefore, Foxf1 has potential as a biomarker of osteogenesis and may be a therapeutic target for PMOP.

7.
Sci Total Environ ; 712: 136362, 2020 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-31935549

RESUMO

Many developing countries including China have launched command-and-control regulation (CCR) to achieve sustainable development. However, we know little about whether CCR promotes green innovation performance. This study empirically analyses the impact of CCR, which is represented by China's eleventh Five-Year Plan (FYP) environmental regulation, on enterprise green innovation performance and use green innovation efficiency as the measure of innovation. Super-SBM DEA model, difference-in-differences (DID) and difference-in-difference-in-differences (DDD) methods are employed to investigate 496 industrial enterprises in China's A-share market for the 2002-2017 period. Moreover, we distinguish each treat group from the control group by using continuous variables and consider enterprise features in the analysis. The results find that, in general, the eleventh FYP environmental regulation negatively influences enterprise green innovation efficiency in a short-term through reducing cash flows. More specifically, the eleventh FYP CCR generates a detrimental effect on small enterprises, state-owned enterprises, and enterprises in China's western and eastern regions. Overall, this empirical analysis suggests that the government should consider the effect of CCR on economy and focus on the heterogeneity of enterprises during designing environmental policies.

8.
Artigo em Inglês | MEDLINE | ID: mdl-31995465

RESUMO

A pink-pigmented, Gram-negative, rod-shaped, obligate aerobic bacterial strain, MIMD6T, was isolated from biological soil crusts in PR China. Cells grew at 20-37 °C (optimum, 30 °C), at pH 6-8 (optimum, pH 7) and with 0-1 % (w/v) NaCl (optimum, 0 %). Strain MIMD6T could use methanol or formate as a sole carbon source to grow, and carried methanol dehydrogenase genes mxa F and xox F, supporting its methylotrophic metabolism. The respiratory quinone was ubiquinone Q-10, the major fatty acids were C18 : 1ω7c (87.3 %), and the major polar lipids were diphosphatidylglycerol, phosphatidylmonomethylethanolamine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine, one unknown aminolipid and one unidentified glycolipid. The results of phylogenetic analyses based on the sequences of the 16S rRNA gene, seven housekeeping genes (dna K, rec A, rim O, rpI K, rpm G, rps R and rpo B) and methanol dehydrogenase genes indicated that strain MIMD6T formed a phylogenetic linage with members of the genus Methylobacterium. Strain MIMD6T was most closely related to Methylobacterium isbiliense DSM 17168T and Methylobacterium nodulans LMG 21967T with 16S rRNA gene sequence similarities of 95.7 and 95.2 %, respectively. The genomic DNA G+C content calculated via draft genome sequencing was 73.0 mol%. The average nucleotide identity and digital DNA-DNA hybridization values between strain MIMD6T and the type strains of other Methylobacterium species were 70.7-82.0 and 24.6-30.0 %, respectively. Based on phenotypic, chemotaxonomic and phylogenetic characteristics, strain MIMD6T represents a novel species of the genus Methylobacterium, for which the name Methylobacterium crusticola sp. nov. is proposed. The type strain is MIMD6T (=KCTC 52305T=MCCC 1K01311T).

9.
EMBO J ; 39(2): e102602, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31802519

RESUMO

Plants establish mutualistic associations with beneficial microbes while deploying the immune system to defend against pathogenic ones. Little is known about the interplay between mutualism and immunity and the mediator molecules enabling such crosstalk. Here, we show that plants respond differentially to a volatile bacterial compound through integral modulation of the immune system and the phosphate-starvation response (PSR) system, resulting in either mutualism or immunity. We found that exposure of Arabidopsis thaliana to a known plant growth-promoting rhizobacterium can unexpectedly have either beneficial or deleterious effects to plants. The beneficial-to-deleterious transition is dependent on availability of phosphate to the plants and is mediated by diacetyl, a bacterial volatile compound. Under phosphate-sufficient conditions, diacetyl partially suppresses plant production of reactive oxygen species (ROS) and enhances symbiont colonization without compromising disease resistance. Under phosphate-deficient conditions, diacetyl enhances phytohormone-mediated immunity and consequently causes plant hyper-sensitivity to phosphate deficiency. Therefore, diacetyl affects the type of relation between plant hosts and certain rhizobacteria in a way that depends on the plant's phosphate-starvation response system and phytohormone-mediated immunity.

10.
Hum Mutat ; 41(1): 212-221, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31489982

RESUMO

Glucose-6-phosphate dehydrogenase (G6PD) deficiency is one of the most common X-linked enzymopathies caused by G6PD gene variant. We aimed to provide the characteristics of G6PD deficiency and G6PD gene variant distribution in a large Chinese newborn screening population. We investigated the prevalence of G6PD in China from 2013 to 2017. Then, we examined G6PD activity and G6PD gene in representative Chinese birth cohort to explore the distribution of G6PD gene variant in 2016. We then performed multicolor melting curve analysis to classify G6PD gene variants in 10,357 neonates with activity-confirmed G6PD deficiency, and DNA Sanger sequencing for G6PD coding exons if hot site variants were not found. The screened population, organizations, and provinces of G6PD deficiency were increased from 2013 to 2017 in China. The top five frequency of G6PD gene variants were c.1376G>T, c.1388G>A, c.95A>G, c.1024C>T, and c.871G>A and varied in different provinces, with regional and ethnic features, and four pathogenic variant sites (c.152C>T, c.290A>T, c.697G>C, and c.1285A>G) were first reported. G6PD deficiency mainly occurs in South China, and the frequency of G6PD gene variant varies in different regions and ethnicities.

11.
J Gene Med ; : e3153, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31881106

RESUMO

BACKGROUND: MicroRNA-647 (miR-647) has been reported to regulate tumor development, although its role in glioma remains unclear. METHODS: miR-647 expression in glioma cells and normal cells was measured using a quantitative real-time polymerase chain reaction. The effects of miR-647 expression on glioma cell proliferation, cell apoptosis, colony formation and cell invasion were measured using a cell counting kit-8 assay, flow cytometry, a colony formation assay and a transwell invasion assay. Luciferase activity reporter and western blot assays were conducted to explore whether homeobox A9 (HOXA9) was a direct target of miR-647. RESULTS: We found that miR-647 expression was downregulated in glioma cell lines compared to the normal cell line. Overexpression of miR-647 inhibits glioma cell proliferation, colony formation and cell invasion, although it promotes apoptosis in vitro. HOXA9 was validated a direct target of miR-647 and the overexpression of HOXA9 reversed the effects of miR-647 on glioma cell behavior. CONCLUSIONS: The identification of the miR-647/HOXA9 axis will advance our understanding underlying glioma progression and provide novel therapeutic targets for glioma treatment.

12.
Mar Genomics ; : 100722, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31677976

RESUMO

Marine Bacteroidetes are well known for their functional specialization on the decomposition of polysaccharides which results from a great number of carbohydrate-active enzymes. Here we represent the complete genome of a Bacteroitedes member Echinicola rosea JL3085T that was isolated from surface seawater of the South China Sea. The genome is 6.06 Mbp in size with a GC content of 44.1% and comprises 4613 protein coding genes. A remarkable genomic feature is that the number of glycoside hydrolase genes in the genome of E. rosea JL3085T is high in comparison with most of the sequenced members of marine Bacteroitedes. E. rosea JL3085T genome harbored multi-gene polysaccharide utilization loci (PUL) systems involved in the degradation of pectin, xylan and arabinogalactan. The large diversity of hydrolytic enzymes supports the use of E. rosea JL3085T as a candidate for biotechnological applications in enzymatic conversion of plant polysaccharides.

13.
Medicine (Baltimore) ; 98(44): e17550, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31689757

RESUMO

BACKGROUND: Cardiac arrest (CA) is a serious threat to human health. Cardiopulmonary resuscitation (CPR) is an effective treatment for CA. Early and high-quality CPR is closely related to the survival rate of patients with CA. But manual chest compression has a lot of defects. To solve the defects and improve the quality of CPR, mechanical CPR device was invented. However, it has still controversy whether manual chest compression or mechanical chest compression is better. This systematic review was aimed to investigate the difference in clinical outcomes between manual chest compression and Lund University Cardiac Assist System (LUCAS) assisted CPR in patients with out-hospital CA. METHODS: Original research studies, conducted on adult out-of-hospital CA, were included. PubMed/Medline, EMBASE, Scopus, Cochrane Library, CNKI, and Wanfang database were searched from the setting to February 21, 2019. Odds ratio (OR) with 95% confidence interval (CI) was selected as effect scale index for evaluation of the difference in return of spontaneous circulation (ROSC), survival to hospital admission, survival to hospital discharge, and survival to 30 days. Random effects model was used in this study to estimate overall mean effects. RESULTS: A total of 6 articles, including 4 randomized controlled trials and 2 nonrandomized controlled trials, were selected. And 8501 subjects were involved to analyze the clinical outcomes of LUCAS and manual chest compression for patients with out-hospital CA. Comparisons of ROSC (33.3% vs 33.0%, P = .98; OR = 1; 95% CI: [0.89,1.13]), survival to hospital admission (22.7% vs 24.3%, P = .32; OR = 0.86; 95% CI: [0.65,1.15]), survival to hospital discharge (8.6% vs 10.7%, P = .50; OR = 0.92; 95% CI: [0.73,1.17]), and survival to 30 days (7.5% vs 8.5%, P = .50; OR = 0.92; 95% CI: [0.73,1.17]) were made. No significant difference was found. CONCLUSION: The synthesis of available evidence does not support that mechanical chest compression with LUCAS device improves clinical outcome in out-of-hospital CA patients compared with manual chest compression. Large scale studies with improved designs are still needed in the future.


Assuntos
Reanimação Cardiopulmonar/instrumentação , Reanimação Cardiopulmonar/métodos , Parada Cardíaca Extra-Hospitalar/mortalidade , Parada Cardíaca Extra-Hospitalar/terapia , Ensaios Clínicos como Assunto , Hospitalização/estatística & dados numéricos , Humanos , Análise de Sobrevida
14.
Cancer Biomark ; 26(3): 375-383, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31594213

RESUMO

BACKGROUND: p16 has often been found to be overexpressed in patients oral squamous cell carcinoma (OSCC), but its prognostic value between anatomic subsites is still unclear. OBJECTIVE: The aim of this study was to investigate the diagnostic and prognostic values of p16 in OSCC originating from tongue, gingiva or buccal mucosa. METHODS: A total of 147 OSCC patients with tumors arising from the tongue, gingiva or buccal mucosa were enrolled in this study. p16 expression was detected using immunohistochemistry (IHC), and the presence of HPV16 was determined by real-time PCR in p16 positive patients. The correlation of p16 expression with the clinical parameters was evaluated. RESULTS: Only one p16 positive patient with a cut off value of 25% and 75% was HPV16 positive. Although overall survival (OS), recurrence free survival (RFS) and metastasis free survival (MFS) had no significant differences between the p16 positive and negative patients, p16 negative patients (cut off value 25%) had more RFS in the buccal mucosa cancer (p= 0.03) than the p16-positive patients. CONCLUSIONS: The prevalence of HPV16 in Chinese OSCC patients was low. p16 overexpression decoupled from HPV infection was not a prognostic marker for OSCC patients except for patients with the buccal mucosa cancer.

15.
Med Sci Monit ; 25: 7361-7369, 2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31570688

RESUMO

BACKGROUND This study aimed to investigate a rabbit model of osteochondral regeneration using three-dimensional (3-D) printed polycaprolactone-hydroxyapatite (PCL-HA) scaffolds coated with umbilical cord blood mesenchymal stem cells (UCB-MSCs) and chondrocytes. MATERIAL AND METHODS Nine female New Zealand white rabbits were included in the study. The 3-D PCL-HA scaffolds were prepared using fused deposition modeling 3-D printing technology. Seeding cells were prepared by co-culture of rabbit UCB-MSCs and chondrocytes with a ratio of 3: 1. A total of 4×106 cells were seeded on 3-D PCL-HA scaffolds and implanted into rabbits with femoral trochlear defects. After 8 weeks of in vivo implantation, 12 specimens were sampled and examined using histology and scanning electron microscopy (SEM). The International Cartilage Repair Society (ICRS) macroscopic scores and histological results were recorded and compared with those of the unseeded PCL-HA scaffolds. RESULTS Mean ICRS scores for the UCB-MSCs and chondrocyte-seeded PCL-HA scaffolds (group A) were significantly higher than the normal unseeded control (NC) PCL-HA scaffold group (group B) (P<0.05). Histology with safranin-O and fast-green staining showed that the UCB chondrocyte-seeded PCL-HA scaffolds significantly promoted bone and cartilage regeneration. CONCLUSIONS In a rabbit model of osteochondral regeneration using 3-D printed PCL-HA scaffolds, the UCB chondrocyte-seeded PCL-HA scaffold promoted articular cartilage repair when compared with the control or non-seeded PCL-HA scaffolds.

16.
Biomed Pharmacother ; 120: 109540, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31639648

RESUMO

BACKGROUND: To investigate the effect of hydrogen peroxide (H2S) on myocardial clock gene Bmal1 in ischemic cardiomyocytes. MATERIALS & METHODS: Quantitative PCR (qPCR) was used to detect the expression of Bmal1 at the mRNA level in H9C2 rat cardiomyocytes. The protein expressions of Bax and Bcl-2, PI3K/Akt, caspase-3 were measured by western blotting. The levels of reactive oxygen species (ROS) were determined by ELISA. RESULTS: The expression level of clock gene Bmal1 demonstrated a clock rhythm of periodic oscillation within 24 h. Compared with the control group, H2S treatment maintained the rhythm of the clock gene in ischemic cardiomyocytes and increased the transcription and expression levels of Bmal1. H2S increased cell survival by activating PI3K/Akt signaling pathway, inhibiting mitochondrial apoptosis signaling, and reducing intracellular oxidative stress. PI3K/Akt and Bmal1 were demonstrated to be involved in H2S protection of cardiomyocyte ischemia. Knockout of Bmal1 gene affects the degree of phosphorylation of Akt and Erk proteins, and the level of ROS production, resulting in a decrease in the protective effects of H2S. CONCLUSION: The expression level of Bmal1 has effects on the function of cardiomyocytes such as ROS production. The potential mechanism by which H2S regulates clock genes may be related to the effect of clock genes on protein phosphorylation levels in ischemic cardiomyocytes.

17.
Int J Mol Sci ; 20(19)2019 Sep 26.
Artigo em Inglês | MEDLINE | ID: mdl-31561542

RESUMO

We designed and synthesized a series of novel 3-arylquinoxaline derivatives and evaluated their biological activities as potential dengue virus (DENV) replication inhibitors. Among them, [3-(4-methoxyphenyl)quinoxalin-2-yl](phenyl)methanol (19a), [6,7-dichloro-3-(4-methoxyphenyl)quinoxalin-2-yl](phenyl)methanol (20a), and (4-methoxyphenyl)(3-phenylquinoxalin-2-yl)methanone (21b) were found to significantly inhibit the DENV RNA expression in Huh-7-DV-Fluc cells with a potency better than that of ribavirin. Compound 19a reduced DENV replication in both viral protein and messenger RNA (mRNA) levels in a dose-dependent manner and exhibited no significant cell cytotoxicity. Notably, compound 19a exhibited a half maximal effective concentration (EC50) value at 1.29 ± 0.74 µM. We further observed that the inhibitory effect of 19a on DENV replication was due to suppression of DENV-induced cyclooxygenase-2 (COX-2) expression. Docking studies also showed that 19a caused hydrophobic interactions at the active sites with Arg29, Glu31, Tyr116, Leu138, Pro139, Lys454, Arg455, and Gln529. The calculated lowest binding energy between the 19a and COX-2 was -9.10 kcal/mol. In conclusion, compound 19a might be a potential lead compound for developing an anti-DENV agent.

18.
IEEE Trans Biomed Circuits Syst ; 13(6): 1405-1416, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31562104

RESUMO

Monolithic integration of photoacoustic (PA) sensor with compact size, lightweight, and low power consumption is attractive to be implemented on wearable medical devices for in vivo blood metabolic sensing and imaging. This work presents a miniaturized chip-scale mixed-signal photoacoustic sensor system which can achieve coherent lock-in function to detect weak target PA signals noninvasively at in vivo scenarios of poor signal to noise ratio (SNR) and strong interferences. A low-noise amplifier (LNA), a 3rd order Butterworth low-pass filter (LPF), and a variable-gain amplifier (VGA) chain with 10 MHz cutoff frequency are implemented on-chip to attain a high-quality sensing performance with 50-dB dynamic range. A Gilbert-cell type multiplier is integrated on-chip to fulfill the coherent lock-in process on acquired PA signals in a closed-loop process with an embedded FPGA system. Fabricated in 65-nm CMOS technology, the prototype PA sensor system demonstrated 50 µV sensitivity. The functions of the chip-scale PA sensor system enhanced by coherent lock-in process were validated through the experiments on temperature monitoring and vessel imaging. The PA receiver chip occupies an area of 0.6 mm2 and consumes 20 mW at a 1.8-V supply.

19.
Int J Mol Sci ; 20(18)2019 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-31540106

RESUMO

Staphylococcus aureus resistance to current antibiotics has become the greatest global challenge facing public health. The development of new antimicrobial agents is urgent and important and is needed to provide additional therapeutic options. In our previous study, we found out that pterostilbene exhibited potent antibacterial activity, especially against methicillin-resistant Staphylococcus aureus (MRSA). According to previous studies, 1,2,3-triazole, with the characteristic of increasing the interaction with the target readily and enhancing water solubility, were widely used in the approved anti-bacterial drugs. Therefore, these results attract our interest to use the structure of pterostilbene as a scaffold for the hybrid 1,2,3-triazole moiety to develop a novel anti-MRSA infection agent. In this study, we demonstrated the design and synthesis of a series of triazolylpterostilbene derivatives. Among these compounds, compound 4d exhibited the most potent anti-MRSA activity with a minimum inhibitory concentration (MIC) value of 1.2-2.4 µg/mL and a minimum bactericidal concentration (MBC) value of 19.5-39 µg/mL. The structure-activity relationship and antibacterial mechanism were investigated in this study. Molecular docking studies were carried out to verify and rationalize the biological results. In this study, the results confirmed that our design could successfully increase the inhibitory activity and specificity against MRSA. Compound 4d could be used as a candidate for anti-bacterial agents and in depth vivo studies should be further investigated.

20.
IEEE Trans Biomed Circuits Syst ; 13(6): 1417-1424, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31502987

RESUMO

Medical monitoring is undergoing a translation from the hospital-based system to the personalized home-based system. With the aim of wearable application of photoacoustic technique, we propose a miniaturized photoacoustic 3D imager for superficial medical imaging. By employing the compact continuous-wave laser diode based optical irradiation and an ultrathin 2D matrix array based photoacoustic detection in the coherent frequency domain, a wearable imaging probe with a size of about 80 × 25 × 24 mm3 and a weight of 21 g is developed. At the backend, an FPGA controlled Howland current source drives the laser diodes to excite linear frequency modulated optical irradiation. Recorded by a portable multichannel data acquisition system, the generated photoacoustic responses are firstly compressed with the coherent frequency domain photoacoustic method and then extrapolated in the wavenumber-frequency domain for fast image reconstruction. With three-wavelength (450 nm, 638 nm, and 808 nm) laser irradiation, photoacoustic imaging can be operated multispectrally, endowing the developed imager with functional imaging capability in 3D space. With the imager worn on the human forearm, hemoglobin oxygen saturation level in superficial arm vasculature can be long-term monitored with high stability. When the imager is applied for imaging in a relatively large area (e.g., early melanoma detection in the human breast), flexible scanning in a handheld manner can be performed. This work opens the application potential of photoacoustic technique in a broad range of areas, including personalized healthcare, home health monitoring, and long-term physiologic monitoring.

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