Elements of key enteric drug metabolism and disposition pathways are reviewed to aid the assessment of the applicability of current cell-based enteric experimental systems for the evaluation of ...enteric metabolism and drug interaction potential. Enteric nuclear receptors include vitamin D receptor, constitutive androstane receptor, pregnane X receptor, farnesoid X receptor, liver X receptor, aryl hydrocarbon receptor, and peroxisome proliferator-activated receptor. Enteric drug metabolizing enzyme pathways include both cytochrome P450 (P450) and non-P450 drug metabolizing enzymes based on gene expression, proteomics, and activity. Both uptake and efflux transporters are present in the small intestine, with P-glycoprotein found to be responsible for most drug-drug and food-drug interactions. The cell-based in vitro enteric systems reviewed are 1) immortalized cell line model: the human colon adenocarcinoma (Caco-2) cells; 2) human stem cell-derived enterocyte models: stem cell enteric systems, either from intestinal crypt cells or induced pluripotent stem cells; and 3) primary cell models: human intestinal slices, cryopreserved human enterocytes, permeabilized cofactor-supplemented (MetMax) cryopreserved human enterocytes, and cryopreserved human intestinal mucosa. The major deficiency with both immortalized cell lines and stem cell-derived enterocytes is that drug metabolizing enzyme activities, although they are detectable, are substantially lower than those for the intestinal mucosa in vivo. Human intestine slices, cryopreserved human enterocytes, MetMax cryopreserved human enterocytes, and cryopreserved human intestinal mucosa retain robust enteric drug metabolizing enzyme activity and represent appropriate models for the evaluation of metabolism and metabolism-dependent drug interaction potential of orally administered xenobiotics including drugs, botanical products, and dietary supplements. SIGNIFICANCE STATEMENT: Enteric drug metabolism plays an important role in the bioavailability and metabolic fate of orally administered drugs as well as in enteric drug-drug and food-drug interactions. The current status of key enteric drug metabolism and disposition pathways and in vitro human cell-based enteric experimental systems for the evaluation of the metabolism and drug interaction potential of orally administered substances is reviewed.
Continuous monitoring of the central-blood-pressure waveform from deeply embedded vessels, such as the carotid artery and jugular vein, has clinical value for the prediction of all-cause ...cardiovascular mortality. However, existing non-invasive approaches, including photoplethysmography and tonometry, only enable access to the superficial peripheral vasculature. Although current ultrasonic technologies allow non-invasive deep-tissue observation, unstable coupling with the tissue surface resulting from the bulkiness and rigidity of conventional ultrasound probes introduces usability constraints. Here, we describe the design and operation of an ultrasonic device that is conformal to the skin and capable of capturing blood-pressure waveforms at deeply embedded arterial and venous sites. The wearable device is ultrathin (240 μm) and stretchable (with strains up to 60%), and enables the non-invasive, continuous and accurate monitoring of cardiovascular events from multiple body locations, which should facilitate its use in a variety of clinical environments.
We report here a novel in vitro experimental system, the metabolism-dependent cytotoxicity assay (MDCA), for the definition of the roles of hepatic drug metabolism in toxicity. MDCA employs ...permeabilized cofactor-supplemented cryopreserved human hepatocytes (MetMax Human Hepatocytes, MMHH), as an exogenous metabolic activating system, and human embryonic kidney 293 (HEK293) cells, a cell line devoid of drug-metabolizing enzyme activity, as target cells for the quantification of drug toxicity. The assay was performed in the presence and absence of cofactors for key drug metabolism pathways known to play key roles in drug toxicity: NADPH/NAD+ for phase 1 oxidation, uridine 5'-diphosphoglucuronic acid (UDPGA) for uridine 5'-diphospho-glucuronosyltransferase (UGT) mediated glucuronidation, 3'-phosphoadenosine-5'-phosphosulfate (PAPS) for cytosolic sulfotransferase (SULT) mediated sulfation, and glutathione (GSH) for glutathione S-transferase (GST) mediated GSH conjugation. Six drugs with clinically significant hepatoxicity, resulting in liver failure or a need for liver transplantation: acetaminophen, amiodarone, cyclophosphamide, ketoconazole, nefazodone, and troglitazone were evaluated. All six drugs exhibited cytotoxicity enhancement by NADPH/NAD+, suggesting metabolic activation via phase 1 oxidation. Attenuation of cytotoxicity by UDPGA was observed for acetaminophen, ketoconazole, and troglitazone, by PAPS for acetaminophen, ketoconazole, and troglitazone, and by GSH for all six drugs. Our results suggest that MDCA can be applied toward the elucidation of metabolic activation and detoxification pathways, providing information that can be applied in drug development to guide structure optimization to reduce toxicity and to aid the assessment of metabolism-based risk factors for drug toxicity. GSH detoxification represents an endpoint for the identification of drugs forming cytotoxic reactive metabolites, a key property of drugs with idiosyncratic hepatotoxicity. SIGNIFICANCE STATEMENT: Application of the metabolism-dependent cytotoxicity assay (MDCA) for the elucidation of the roles of metabolic activation and detoxification pathways in drug toxicity may provide information to guide structure optimization in drug development to reduce hepatotoxic potential and to aid the assessment of metabolism-based risk factors. Glutathione (GSH) detoxification represents an endpoint for the identification of drugs forming cytotoxic reactive metabolites that may be applied toward the evaluation of idiosyncratic hepatotoxicity.
AbstractThe production of the architecture engineering and construction (AEC) industry is organized by projects. With the diffusion of information and communication technology in the industry, ...building information modeling (BIM) is widely adopted in AEC projects. However, the systematic implementation of BIM in AEC projects experiences challenges. This study aims to identify critical strategies for enhancing BIM implementation within the AEC project context. Initially, 17 strategies are drawn from a comprehensive review of the relevant literature. Through a questionnaire survey with 116 effective responses from the practitioners, ten critical strategies are identified, with the top five being clearly defined plans and objectives for BIM implementation, financial support, capabilities and skills in BIM technology, availability and interoperability of engineering information and data, and the aligned objective of BIM implementation with the project goal. The study also investigates the possible discrepancy in the different actors’ assessments on the criticality of the strategies to validate the survey. The further principal component analysis groups the strategies and finds five latent factors of the strategies, including institutional governance, change accommodation, technical environment, cooperation, and resources. This finding reveals that systematic BIM implementation is inevitably associated with the AEC project context and indicates that the enhancement of current BIM implementation in projects covers the strategies of the technical, institutional, and managerial aspects to accommodate changes brought by BIM. An international comparison of the top drivers with the found peer studies from Nigeria, Singapore, and Turkey classifies leadership as a driving force to incorporate BIM into the AEC projects. The results provide implications for enhancing BIM implementation in AEC projects and may help improve the efficiency of the industry.
Hepatic gene expression as a function of culture duration was evaluated in prolonged cultured human hepatocytes. Human hepatocytes from seven donors were maintained as near-confluent ...collagen-Matrigelsandwich cultures, with messenger RNA expression for genes responsible for key hepatic functions quantified by real-time polymerase chain reaction at culture durations of 0 (day of plating), 2, 7, 9, 16, 23, 26, 29, 36, and 43 days. Key hepatocyte genes were evaluated, including the differentiation markers albumin, transferrin, and transthyretin; the hepatocyte-specific asialoglycoprotein receptor 1 cytochrome P450 isoforms CYP1A2, CYP2B6, CYP2C8, CYP2C9, CYP2C19, CYP2D6, CYP3A4, and CYP3A7; uptake transporter isoforms SLC10A1, SLC22A1, SLC22A7, SLCO1B1, SLCO1B3, and SLCO2B1; efflux transporter isoforms ATP binding cassette (ABC)B1, ABCB11, ABCC2, ABCC3, ABCC4, and ABCG2; and the nonspecific housekeeping gene hypoxanthine ribosyl transferase 1 (HPRT1). The well established dedifferentiation phenomenon was observed on day 2, with substantial (>80%) decreases in gene expression in day 2 cultures observed for all genes evaluated except HPRT1 and efflux transporters ABCB1, ABCC2, ABCC3 (<50% decrease in expression), ABCC4 (>400% increase in expression), and ABCG2 (no decrease in expression). All genes with a >80% decrease in expression were found to have increased levels of expression on day 7, with peak expression observed on either day 7 or day 9, followed by a gradual decrease in expression up to the longest duration evaluated of 43 days. Our results provide evidence that cultured human hepatocytes undergo redifferentiation upon prolonged culturing. SIGNIFICANCE STATEMENT: This study reports that although human hepatocytes underwent dedifferentiation upon 2 days of culture, prolonged culturing resulted in redifferentiation based on gene expression of differentiation markers, uptake and efflux transporters, and cytochrome P450 isoforms. The observed redifferentiation suggests that prolonged (>7 days) culturing of human hepatocyte cultures may represent an experimental approach to overcome the initial dedifferentiation process, resulting in "stabilized" hepatocytes that can be applied toward the evaluation of drug properties requiring an extended period of treatment and evaluation.
Construction is a high hazard industry which involves many factors that are potentially dangerous to workers. Safety has always been advocated by many construction companies, and they have been ...working hard to make sure their employees are protected from fatalities and injuries. With the advent of Virtual and Augmented Reality (VR/AR), there has been a witnessed trend of capitalizing on sophisticated immersive VR/AR applications to create forgiving environments for visualizing complex workplace situations, building up risk-preventive knowledge and undergoing training. To better understand the state-of-the-art of VR/AR applications in construction safety (VR/AR-CS) and from which to uncover the related issues and propose possible improvements, this paper starts with a review and synthesis of research evidence for several VR/AR prototypes, products and the related training and evaluation paradigms. Predicated upon a wide range of well-acknowledged scholarly journals, this paper comes up with a generic taxonomy consisting of VR/AR technology characteristics, application domains, safety scenarios and evaluation methods. According to this taxonomy, a number of technical features and types that could be implemented in the context of construction safety enhancement are derived and further elaborated, while significant application domains and trends regarding the VR/AR-CS research are generalized, i.e., hazards recognition and identification, safety training and education, safety instruction and inspection, and so on. Last but not least, this study sets forth a list of gaps derived from the in-depth review and comes up with the prospective research works. It is envisioned that the outcomes of this paper could assist both researchers and industrial practitioners with appreciating the research and practice frontier of VR/AR-CS and soliciting the latest VR/AR applications.
•90 VR/AR-CS related articles from 2000 to 2017 are reviewed•The review taxonomy was consolidated by technology characteristics, application domains, safety enhancement mechanisms, and safety assessment and evaluation•The top three application domains include hazards identification, safety education and training, and safety inspection and instruction
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
The recent developments in the isolation, culturing, and cryopreservation of human hepatocytes, and the application of the cells in drug development are reviewed. Recent advances include the ...improvement of cryopreservation procedures to allow cell attachment, thereby extending the use of the cells to assays that requires prolong culturing such as enzyme induction studies. Applications of human hepatocytes in drug development include the evaluation of metabolic stability, metabolite profiling and identification, drug–drug interaction potential, and hepatotoxic potential. The use of intact human hepatocytes, because of the complete, undisrupted metabolic pathways and cofactors, allows the development of data more relevant to humans in vivo than tissue fractions such as human liver microsomes. Incorporation of key in vivo factors with the intact hepatocytes in vitro may help predictive human in vivo drug properties. For instance, evaluation of drug metabolism and drug–drug interactions with intact human hepatocytes in 100% human serum may eliminate the need to determine in vivo intracellular concentrations for the extrapolation of in vitro data to in vivo. Co-culturing of hepatocytes and nonhepatic primary cells from other organs in the integrated discrete multiple organ co-culture (IdMOC) may allow the evaluation of multiple organ interactions in drug metabolism and drug toxicity. In conclusion, human hepatocytes represent a critical experimental model for drug development, allowing early evaluation of human drug properties to guide the design and selection of drug candidates with a high probability of clinical success.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Silicon nanowire (SiNW) sensors have been developed by using top-down fabrication that is CMOS (complementary metal-oxide-semiconductor) compatible for resistive chemical detection with fast response ...and high sensitivity. Top-down fabrication by electron beam lithography and reactive ion etching of a silicon on insulator (SOI) substrate enables compatibility with the CMOS fabrication process, accurate alignment with other electrical components, flexible design of the nanowire geometry and good control of the electrical characteristics. The SiNW sensors showed a large operation range for pH detection (pH = 4-10) with an average sensitivity of (Delta R/R)/pH = 2.6%/pH and a rise time of 8 s. A small pH level difference (Delta pH = 0.2) near neutral pH conditions (pH = 7) could be resolved with the SiNW sensors. The sensor response to the presence of alkali metal ions and the long term drifting effects were also investigated.
We report in this work successful isolation and cryopreservation of enterocytes from human small intestine. The enterocytes were isolated by enzyme digestion of the intestinal lumen, followed by ...partial purification via differential centrifugation. The enterocytes were cryopreserved directly after isolation without culturing to maximize retention of in vivo drug-metabolizing enzyme activities. Post-thaw viability of the cryopreserved enterocytes was consistently over 80% based on trypan blue exclusion. Cryopreserved enterocytes pooled from eight donors (four male and four female) were evaluated for their metabolism of 14 pathway-selective substrates: CYP1A2 (phenacetin hydroxylation), CYP2A6 (coumarin 7-hydroxylation), CYP2B6 (bupropion hydroxylation), CYP2C8 (paclitaxel 6
-hydroxylation), CYP2C9 (diclofenac 4-hydroxylation), CYP2C19 (
-mephenytoin 4-hydroxylation), CYP2D6 (dextromethorphan hydroxylation), CYP2E1 (chlorzoxazone 6-hydroxylation), CYP3A4 (midazolam 1'-hydroxylation and testosterone 6
-hydroxylation), CYP2J2 (astemizole O-demethylation), UDP-glucuronosyltransferase (UGT; 7-hydroxycoumarin glucuronidation), sulfotransferase (SULT; 7-hydroxycoumarin sulfation), and carboxylesterase 2 (CES2; irinotecan hydrolysis) activities. Quantifiable activities were observed for CYP2C8, CYP2C9, CYP2C19, CYP2E1, CYP3A4, CYPJ2, CES2, UGT, and SULT, but not for CYP1A2, CYP2A6, CYP2B6, and CYP2D6. Enterocytes from all 24 donors were then individually evaluated for the quantifiable drug metabolism pathways. All demonstrated quantifiable activities with the expected individual variations. Our results suggest that cryopreserved human enterocytes represent a physiologically relevant and convenient in vitro experimental system for the evaluation of intestinal metabolism, akin to cryopreserved human hepatocytes for hepatic metabolism.
Current challenges in accurately predicting intestinal metabolism arise from the complex nature of the intestine, leading to limited applicability of available in vitro tools, as well as knowledge ...deficits in intestinal physiology, including enzyme abundance. In particular, information on regional enzyme abundance along the small intestine is lacking, especially for non-cytochrome P450 (non-CYP) enzymes such as carboxylesterases (CES), UDP-glucuronosyltransferases (UGTs), and sulfotransferases (SULTs). We used cryopreserved human intestinal mucosa (CHIM) samples from nine donors as an in vitro surrogate model for the small intestine and performed LC-MS/MS-based quantitative proteomics for 17 non-CYP enzymes, using stable isotope-labeled peptides. Relative protein quantification was done by normalization with enterocyte marker proteins, i.e., villin-1, sucrase isomaltase, and fatty acid binding protein 2, and absolute protein quantification is reported as pmol per mg protein. Activity assays in glucuronidations and sequential metabolisms were conducted to validate the proteomics findings. Relative or absolute quantifications are reported for CES1, CES2, five UGTs, and four SULTs along the small intestine: duodenum, jejunum, and ileum for six donors and in ten segments along the entire small intestine (A - J) for three donors. Relative quantification using marker proteins may be beneficial in further controlling for technical variabilities. Absolute quantification data will allow for scaling factor generation and in vivo extrapolation of intestinal clearance using physiologically-based pharmacokinetic (PBPK) modeling. SIGNIFICANCE STATEMENT: Current knowledge gaps exist in intestinal protein abundance of non-cytochrome P450 (non-CYP) enzymes. Here, we employ quantitative proteomics to measure non-CYP enzymes along the human small intestine in 9 donors, using cryopreserved human intestinal mucosa (CHIM) samples. Absolute protein abundances are reported, as well as relative protein abundance normalized with enterocyte markers. Corresponding activities are also examined.
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