Carbon nanodots in endothelial cells and C57BL/6 mice: a study of toxicity and anti-inflammatory effect

The advancement of therapy for cardiovascular disease (CVD) is paramount to public health, as it is the leading global cause of mortality [1]. Nanomedicine provides new opportunities in the ongoing efforts to reduce the economic and healthcare consequences of CVD. Carbon nanodots (CNDs) green-synthesized from microwave pyrolysis of ethylenediamine and citric acid are spherical, ~3 nm in diameter, and possess exceptional hydrophilic, biocompatible, fluorescent, and anti-oxidant properties. However, there is no current report on how these CNDs affect the cardiovascular system, particularly their potential in mediating endothelial dysfunction and cardiovascular disease (CVD). As a known biomarker of inflammation, Oxidized-LDL (Ox-LDL) induces inflammatory gene expression and monocyte extravasation that leads to atherosclerotic development. This study examines the role of CNDs in mediating Ox-LDL induced inflammation in human microvascular endothelial cells (HMEC-1). Our results demonstrate that CNDs can reduce Ox-LDL induced monocyte adhesion in HMEC-1s, which demonstrates their anti-inflammatory effects. The relative gene expression of the cytokine interleukin-8 (IL-8) was reduced by the addition of CNDs, which implies their action in mediating monocyte recruitment to the site of inflammation. While reactive oxygen species (ROS) perform many essential functions, their overproduction disrupts cellular oxidative balance, induces EC dysfunction, and leads to an inflammatory state. Studying the action of CNDs through Electron paramagnetic resonance (EPR) spectroscopy showed direct superoxide and hydroxyl radical-scavenging by CNDs. This result implies that the anti-inflammatory effects of CNDs seen in vitro are attributed to their direct scavenging of ROS. Furthermore, CNDs were found to ameliorate the cytotoxicity caused by Ox-LDL in HMEC-1s. Viability assays showed CNDs were not cytotoxic at measured concentrations to HMEC-1s in vitro. Animal studies involving mice did not show any morphological or physical changes between the CND and control groups. These collective results demonstrate the potential of CNDs to reduce inflammation and cytotoxicity caused by Ox-LDL in HMEC-1s, which implies their use in the development of novel therapy for cardiovascular disease

Regulation of Myc and its localization to Histone Locus Body in Drosophila

Myc is a transcriptional factor required for normal growth and development in vertebrates and invertebrates alike. Loss of function mutations in Myc can cause embryonic lethality in mammals and larval death in flies whereas an increase in its activity can lead to tumorigenesis. Therefore, proper regulation of Myc is very important to ensure normal development. Regulation of Myc occurs by several context specific mechanisms. One such mechanism is the negative feedback autoregulation of Myc and this mechanism is lost in all tumorigenic cell lines. Like its mammalian homolog, the Drosophila Myc (dMyc) undergoes autoregulation in the presence of an ectopic myc gene leading to a Myc null phenotype. Polycomb (Pc), a chromatin binding repressor is required for Myc autoregulation. Upon Pc knockdown, levels of Su(z)2, a Pc group related protein increase significantly, suggesting that Pc represses Su(z)2. We show here that ectopic Su(z)2 can interfere with Myc autorepression and restore endogenous Myc levels as well as rescue larval lethality caused due to Myc autorepression. Su(z)2 does not however, affect general repression by Myc suggesting that repression of myc locus occurs by a different mechanism. During this study we observed that Myc protein forms distinct puncta in certain tissues. Upon investigating we found that these Myc "spots" localize to sub-nuclear organelles known as Histone Locus Body (HLB). HLBs are histone pre-mRNA processing centers formed at histone gene locus. We show here that Myc localizes to the HLBs only during the S phase. Since hisones are transcribed only during S phase we hypothesize that Myc aids in histone transcription, a novel role for Myc

Clinical and Genetic Features of Choroideremia in Childhood.

PURPOSE: To review the functional and anatomic characteristics of choroideremia in the pediatric population, aiming to describe the earliest features of the disease and to identify biomarkers useful for monitoring disease progression. DESIGN: Retrospective case series. PARTICIPANTS: Children diagnosed with choroideremia at a single institution. METHODS: Patients were identified using an electronic patient record system. Case notes and retinal imaging (color fundus photography [CFP], spectral-domain [SD] optical coherence tomography [OCT], and fundus autofluorescence [FAF]) then were reviewed. The results of genetic testing also were recorded. MAIN OUTCOME MEASURES: Presenting symptoms, visual acuity, fundus changes (CFP, SD OCT, FAF), and CHM sequencing results. RESULTS: Twenty-nine patients were identified with a mean age at referral of 9 years (range, 3-16 years). CHM mutations were identified in 15 of 19 patients tested. Nyctalopia was the predominant symptom (66%). Five of 29 patients were asymptomatic at presentation. At the final follow-up visit (mean age, 16 years; range, 7-26 years), most maintained excellent visual acuity (mean, 0.98±0.13 decimalized Snellen acuity). The first sign of retinopathy was widespread pigment clumping at the level of the retinal pigment epithelium (RPE). This later evolved to chorioretinal atrophy, most marked in the mid-peripheral retina. Peripapillary atrophy also was an early feature and was progressive in nature. Three different zones of FAF change were visible. Persistence of the inner retinal layers, detected by SD OCT, was visible at presentation in 15 of 27 patients. Subfoveal choroidal thickness decreased with age, whereas central retinal thickness increased over a similar interval. Four patients in whom visual acuity decreased over the follow-up period recorded a reduction in central retinal thickness. CONCLUSIONS: Progressive structural changes occur at a time when central visual function is maintained. Pigmentary changes at the level of the RPE occur early in the disease course. Peripapillary chorioretinal atrophy, central retinal thickness, and subfoveal choroidal thickness are likely to be valuable in monitoring disease progression and should be considered as potential biomarkers in future therapeutic trials

Inhibition of Cytochrome P450 2E1 and Cytochrome P450 2A6 by essential oils: tarragon (Artemisia dracunculus) and basil (Ocimum basilicum)

Cytochrome P450 enzymes are involved in the metabolism of foreign substances that are present within living organisms. These P450s are classified as Phase I metabolizing enzymes that are found mainly in the liver, they belong to a superfamily of heme containing monoxygenases that are required for metabolism for a number of xenobiotics. Mechanistic approach by these enzymes involves carrying out the oxidation of carbon and nitrogen groups usually resulting in the addition of an alcohol. Cytochrome P450 enzymes have been involved in the bioactivation of inactive compounds to active electrophiles that can contribute to the production of reactive oxygen species, such as superoxide, free radicals, and peroxides. These ROS can contribute to oxidative stress, which leads to hepatic cell necrosis, lipid peroxidation, and DNA adduct formation. This study focuses on two specific Cytochrome P450s, CYP2E1 and CYP2A6. These enzymes have shown to have one of the highest rates of uncoupling among all P450s, this uncoupling leads to the production of ROS. This study focuses on finding potential inhibitors that decrease the chances of these uncoupling reactions from occurring. Human, rat, and rabbit liver microsomes were used for these studies. A series of essential oils were screened with these P450s to determine their inhibitory affects on the enzyme. From these studies, tarragon (Artemisia dracunculus) and basil (Ocimum basilicum) showed the highest inhibitory affects on the enzyme. The major constituent for both these oils was estragole, this was also confirmed via GCMS testing, because of this it was thought that it was a major reason to why the enzyme activity is being inhibited. With the initial screening data showing inhibition of CYP2E1 and CYP2A6, next goal was to determine how potent these oils were and what is the mode of inhibition, reversible or irreversible. The results of CYP2E1 and CYP2A6 with human, rat, and rabbit concluded that both essential oils and estragole inhibited the activity of the enzyme. Estragole was the most potent inhibitor of both enzymes in all 3 species. The KI value for estragole with CYP2E1 in humans was 22.4 µM, in rat 143 µM, and in rabbit 108 µM. The KI value for estragole with CYP2A6 in humans was 27.5 µM and in rabbit was 49.3 µM. Results show that the mode of inhibition shown by both these essential oils and estragole was non-competitive and a reversible type of interaction occurred with both Cytochrome P450 enzymes

Managerial risk in information technology investments : effects of framing, narrow framing and time inconsistent preferences on real options exercise decisions

Real options theory has been advocated as a solution to risky IT investment decisions. IT investments decisions are risky due to uncertainty around future outcomes and the inability of traditional financial measures (like NPV, IRR) to account for inherent managerial flexibility. On the one hand, it is argued that real options analysis captures and formalizes managers' intuition, hence creating a disciplined decision making process. On the other hand, the intuitive valuation of the options is criticized due to the prevalent effects of various judgmental biases. In this dissertation, we explore three potential biases that can affect the real option exercise decisions in terms of either suboptimal option exercise choice due to framing and narrow framing effects, or suboptimal exercise time due to time inconsistent preferences of IT managers. We test for framing effects in individual IT project decisions and narrow framing effects in IT portfolio decisions, by conducting an online experiment among top and mid-level IT professionals. The results show that IT professionals are prone to framing real options at exercise time and simplifying complicated real option exercise decisions by isolating them in IT portfolios. Further, their decisions are influenced by their personal risk preferences. We analyze the effect of time-inconsistent preferences of present-biased managers on the exercise time of real growth and abandonment options and the realized values using a discrete time option valuation model. The results show that present-biased managers are more likely to exercise growth options early when the net payoffs are low, the growth option payoffs have high volatility, and the risk free discount rate is small. Also, present-biased managers are more likely to exercise abandonment option late when the net payoffs from continuing the project are high, salvage value of the project is low, and the rate of change in the salvage value over the period of time is low. In addition, present biased managers are more likely to exercise a growth option early in its life when the project is performing well. We provide implications for practice and IT governance

ACOUSTIC SIGNAL PROPAGATION CHARACTERIZATION OF CONDUIT NETWORKS

Analysis of acoustic signal propagation in conduit networks has been an important area of research in acoustics. One major aspect of analyzing conduit networks as acoustic channels is that a propagating signal suffers frequency dependent attenuation due to thermo-viscous boundary layer effects and the presence of impedance mismatches such as side branches. The signal attenuation due to side branches is strongly influenced by their numbers and dimensions such as diameter and length. Newly developed applications for condition based monitoring of underground conduit networks involve measurement of acoustic signal attenuation through tests in the field. In many cases the exact installation layout of the field measurement location may not be accessible or actual installation may differ from the documented layout. The lack of exact knowledge of numbers and lengths of side branches, therefore, introduces uncertainty in the measurements of attenuation and contributes to the random variable error between measured results and those predicted from theoretical models. There are other random processes in and around conduit networks in the field that also affect the propagation of an acoustic signal. These random processes include but are not limited to the presence of strong temperature and humidity gradients within the conduits, blockages of variable sizes and types, effects of aging such as cracks, bends, sags and holes, ambient noise variations and presence of variable layer of water. It is reasonable to consider that the random processes contributing to the error in the measured attenuation are independent and arbitrarily distributed. The error, contributed by a large number of independent sources of arbitrary probability distributions, is best described by an approximately normal probability distribution in accordance with the central limit theorem. Using an analytical approach to model the attenuating effect of each of the random variable sources can be very complex and may be intractable. A tractable approach is to develop an empirical model of the attenuation that has a stochastic component of a finite mean and variance to account for the random variable error akin to addition of a normally distributed random variable shadowing component in the path loss models of radio frequency (RF) wireless communication channels. This approach forms the crux of the present study. To develop an empirical model, a large number of measurements in conduit networks were made in the field and in a laboratory test set up to measure the variability of attenuation with variation in four parameters. These parameters include distance of the receiver from the source, frequency, numbers and lengths of side branches. Variation in signal attenuation with distance at each transmitted frequency is predicted by using linear regression through the scatter plot of the measured data. Variations in signal attenuation due to change in frequency, number and lengths of side branches are measured in the field and laboratory tests by comparing the reference transmitted pressure with the received pressure at either the open end or at some distance away from the source along the conduit length. Residuals between measured and predicted sound pressure levels are computed and tested for normal probability distribution through a graphical method as well as a statistical goodness of fit test for quantifiable results. The findings indicate that an empirical model of signal attenuation, which includes a normally distributed random variable component to account for random variable errors in the attenuation measurements, gives a more accurate prediction of received acoustic signal strength in a conduit compared to existing theoretical models

Slider crank wave energy converter performance analysis with adaptive autoregressing filtering

This study investigates a performance analysis of wave excitation force prediction to extract wave power for a slider crank power take-off system (PTOS) based on auto regressive (AR) filters. To efficiently convert wave energy into electricity, the prediction of wave excitation forces into near future to keep the generator and the wave excitation force in sync is important for maximum energy extraction. The study shows a prediction methodology of half period and zero crossings in the practical scenario of irregular ocean waves. The prediction has been tested for different wave periods and with different filter orders in noisy and noiseless environment. The prediction results have been used in the PTOS simulation to analyze the energy extraction. It has been shown that the prediction accuracy in the wave half period between the truth data and the predicted data drives the WEC energy extraction efficiency. The amplitude of the wave force is not used and hence the prediction deviation in the wave force amplitude does not affect the PTOS energy extraction. Further analysis shows that the optimum energy can be extracted at 15th order filter with moderate prediction horizon length

Advanced diagnostic genetic testing in inherited retinal disease: experience from a single tertiary referral centre in the UK National Health Service

In 2013, as part of our genetic investigation of patients with inherited retinal disease, we utilized multigene panel testing of 105 genes known to cause retinal disease in our patient cohorts. This test was performed in a UK National Health Service (NHS) accredited laboratory. The results of all multigene panel tests requested between 1.4.13 and 31.8.14 were retrospectively reviewed. All patients had been previously seen at Moorfields Eye Hospital, London, UK and diagnosed with an inherited retinal dystrophy after clinical examination and detailed retinal imaging. The results were categorized into three groups: (i) Testing helped establish a certain molecular diagnosis in 45 out of 115 (39%). Variants in USH2A (n = 6) and RP1 (n = 4) were most common. (ii) Definitive conclusions could not be drawn from molecular testing alone in 13 out of 115 (11%) as either insufficient pathogenic variants were discovered or those identified were not consistent with the phenotype. (iii) Testing did not identify any pathogenic variants responsible for the phenotype in 57 out of 115 (50%). Multigene panel testing performed in an NHS setting has enabled a molecular diagnosis to be confidently made in 40% of cases. Novel variants accounted for 38% of all identified variants. Detailed retinal phenotyping helped the interpretation of specific variants. Additional care needs to be taken when assessing polymorphisms in genes that have been infrequently associated with disease, as historical techniques were not as rigorous as contemporary ones. Future iterations of sequencing are likely to offer higher sensitivity, testing a broader range of genes, more rapidly and at a reduced cost

Knowledge of pelvic floor problems: a study of third trimester, primiparous women

INTRODUCTION AND HYPOTHESIS: Pelvic floor problems in women (urinary incontinence, faecal incontinence, uterovaginal prolapse) are common, and have an adverse effect on quality of life. We hypothesized that there is low knowledge of these problems amongst primiparous women in their third trimester of pregnancy. METHODS: We conducted a cross-sectional study in antenatal clinics of three hospitals in London, UK, from 2011 to 2013. Primiparous women aged ≥18 years and in the third trimester of pregnancy answered questions on pelvic floor problems. Knowledge scores were calculated based on the proportion of questions answered correctly. RESULTS: A total of 249 women completed the question set. The average knowledge score across all domains was low at 45 %. Scores were lowest for the less common problems of faecal incontinence (35 %) and prolapse (36 %). The score for urinary incontinence was higher at 63 %, but low when questions explored more detailed levels of knowledge (41 %). Knowledge scores were positively associated with both education to tertiary level and the use of books as the information source on pregnancy and delivery. Only 35 % of women cited antenatal classes as a source. CONCLUSIONS: Knowledge of pelvic floor problems is low amongst third-trimester, primiparous women in this London-based population. Adequate knowledge of these problems is important for women to be able to make informed choices about their antenatal care and to seek help if problems arise. The data suggest scope for health-care professionals to raise these issues early during pregnancy, and to help women access accurate sources of information

Complement C3 variant and the risk of age-related macular degeneration

Background: Age-related macular degeneration is the most common cause of blindness in Western populations. Susceptibility is influenced by age and by genetic and environmental factors. Complement activation is implicated in the pathogenesis.Methods: We tested for an association between age-related macular degeneration and 13 single-nucleotide polymorphisms (SNPs) spanning the complement genes C3 and C5 in case subjects and control subjects from the southeastern region of England. All subjects were examined by an ophthalmologist and had independent grading of fundus photographs to confirm their disease status. To test for replication of the most significant findings, we genotyped a set of Scottish cases and controls.Results: The common functional polymorphism rs2230199 (Arg80Gly) in the C3 gene, corresponding to the electrophoretic variants C3S (slow) and C3F (fast), was strongly associated with age-related macular degeneration in both the English group (603 cases and 350 controls, P=5.9 x 10(sup -5)) and the Scottish group (244 cases and 351 controls, P=5.0 x 10(sup -5)). The odds ratio for age-related macular degeneration in C3 S/F heterozygotes as compared with S/S homozygotes was 1.7 (95% confidence interval [CI], 1.3 to 2.1); for F/F homozygotes, the odds ratio was 2.6 (95% CI, 1.6 to 4.1). The estimated population attributable risk for C3F was 22%.Conclusions: Complement C3 is important in the pathogenesis of age-related macular degeneration. This finding further underscores the influence of the complement pathway in the pathogenesis of this disease