Direct Measurements of Oxygen Gradients in Spheroid Culture System Using Electron Parametric Resonance Oximetry.

Advanced in vitro culture from tissues of different origin includes three-dimensional (3D) organoid micro structures that may mimic conditions in vivo. One example of simple 3D culture is spheroids; ball shaped structures typically used as liver and tumour models. Oxygen is critically important in physiological processes, but is difficult to quantify in 3D culture: and the question arises, how small does a spheroid have to be to have minimal micro-environment formation? This question is of particular importance in the growing field of 3D based models for toxicological assessment. Here, we describe a simple non-invasive approach modified for the quantitative measurement and subsequent evaluation of oxygen gradients in spheroids developed from a non-malignant fish cell line (i.e. RTG-2 cells) using Electron Paramagnetic Resonance (EPR) oximetry. Sonication of the paramagnetic probe Lithium phthalocyanine (LiPc) allows for incorporation of probe particulates into spheroid during its formation. Spectra signal strength after incorporation of probe into spheroid indicated that a volume of 20 μl of probe (stock solution: 0.10 mg/mL) is sufficient to provide a strong spectra across a range of spheroid sizes. The addition of non-toxic probes (that do not produce or consume oxygen) report on oxygen diffusion throughout the spheroid as a function of size. We provide evidence supporting the use of this model over a range of initial cell seeding densities and spheroid sizes with the production of oxygen distribution as a function of these parameters. In our spheroid model, lower cell seeding densities (∼2,500 cells/spheroid) and absolute size (118±32 μm) allow control of factors such as pre-existing stresses (e.g. ∼ 2% normoxic/hypoxic interface) for more accurate measurement of treatment response. The applied methodology provides an elegant, widely applicable approach to directly characterize spheroid (and other organoid) cultures in biomedical and toxicological research

Correction: Direct Measurements of Oxygen Gradients in Spheroid Culture System Using Electron Parametric Resonance Oximetry.

[This corrects the article DOI: 10.1371/journal.pone.0149492.]

Evidence of Coronavirus (CoV) Pathogenesis and Emerging Pathogen SARS-CoV-2 in the Nervous System: A Review on Neurological Impairments and Manifestations.

The coronavirus disease 2019 (COVID-19) pandemic is an issue of global significance that has taken the lives of many across the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the virus responsible for its pathogenesis. The pulmonary manifestations of COVID-19 have been well described in the literature. Initially, it was thought to be limited to the respiratory system; however, we now recognize that COVID-19 also affects several other organs, including the nervous system. Two similar human coronaviruses (CoV) that cause severe acute respiratory syndrome (SARS-CoV-1) and Middle East respiratory syndrome (MERS-CoV) are also known to cause disease in the nervous system. The neurological manifestations of SARS-CoV-2 infection are growing rapidly, as evidenced by several reports. There are several mechanisms responsible for such manifestations in the nervous system. For instance, post-infectious immune-mediated processes, direct virus infection of the central nervous system (CNS), and virus-induced hyperinflammatory and hypercoagulable states are commonly involved. Guillain-Barré syndrome (GBS) and its variants, dysfunction of taste and smell, and muscle injury are numerous examples of COVID-19 PNS (peripheral nervous system) disease. Likewise, hemorrhagic and ischemic stroke, encephalitis, meningitis, encephalopathy acute disseminated encephalomyelitis, endothelialitis, and venous sinus thrombosis are some instances of COVID-19 CNS disease. Due to multifactorial and complicated pathogenic mechanisms, COVID-19 poses a large-scale threat to the whole nervous system. A complete understanding of SARS-CoV-2 neurological impairments is still lacking, but our knowledge base is rapidly expanding. Therefore, we anticipate that this comprehensive review will provide valuable insights and facilitate the work of neuroscientists in unfolding different neurological dimensions of COVID-19 and other CoV associated abnormalities

IMPACT OF DIFFERENT STARTING DOSES OF ATORVASTATIN ON REACHING TARGET LOW DENSITY LIPOPROTEIN CHOLESTEROL LEVELS AND HEALTH RELATED QUALITY OF LIFE IN DYSLIPIDEMIC PATIENTS

Methods : A prospective, double blind, parallel groups, unicentric study of patients of dyslipidemia, randomized to receive atorvastatin 10 mg (n=75) or atorvastatin 20 mg (n=75) once daily for 12 weeks. Safety reporting of incidence of adverse events was done. Results : Significantly more number of patients (P<0.05) reached target LDL-C levels at the end of 12 weeks in the 20 mg group (77.27% in the high risk group, 100% in moderately high risk group and 100% in the moderate risk group) when compared to 10 mg group (32% in the high risk group, 75% in moderately high risk group and 83.33% in the moderate risk group). Increase in HRQOL at the end of 12 weeks was also significantly greater (P<0.001) in 20 mg group (27.89%) vs. 10 mg group (19.26%). Conclusions : Selecting the starting dose of atorvastatin according to the patients risk category (by using the Framingham's algorithm for calculating cardiovascular risk) and the percentage reduction in LDL required, will result in greater success in achieving LDL goals and better quality of life

Overcoming drug delivery barriers and challenges in topical therapy of atopic dermatitis: A nanotechnological perspective.

Atopic dermatitis (AD) is an inflammatory disorder centered around loss of epidermal barrier function, and T helper 2 (Th2) immune responses. The current understanding of disease heterogeneity and complexity, limits the rational use of existing topical, systemic therapeutic agents, but paves way for development of advanced therapeutic agents. Additionally, advanced nanocarriers that deliver therapeutics to target cells, seem to offer a promising strategy, to overcome intrinsic limitations and challenges of conventional, and traditional drug delivery systems. Ever-evolving understanding of molecular target sites and complex pathophysiology, adverse effects of current therapeutic options, inefficient disease recapitulation by existing animal models are some of the challenges that we face. Also, despite limited success in market translatibility, nanocarriers have demonstrated excellent preclinical results and have been extensively studied for AD. Detailed research on behavior of nanocarriers in different patients and tailored therapy to account for phenotypic variability of the disease are the new research avenues that we look forward to

Formulation and Development of Adapalene Topical Nanohydrogel Using Different Surfactants and Cosurfactants for Antiacne Activity: In Vitro and Ex Vivo Evaluation

A formulation of an adapalene nanohydrogel (ADP-NH) using different surfactants and cosurfactants for topical application was developed and characterized. The best formulation was obtained with nanohydrogel (NH) containing Tween-80- (NH-Tween-80-) incorporated carbopol-940 and ethanol, 0.67% and 3.00% w / w , respectively. The optimized formulations of NH-Tween-80, nanohydrogel containing sodium lauryl sulphate (NH-SLS), and nanohydrogel containing glycerol (NH-glycerol) were separately evaluated to examine their in vitro and ex vivo permeability characteristics and compared with 0.3% dimethyl sulfoxide (control) solution. The polydispersity index of NH-Tween-80, NH-SLS, and NH-glycerol were found to be 0.264 ± 0.312 , 0.382 ± 0.0045 , and 0.310 ± 0.412 , respectively. All NH formulations showed pH within human skin pH ranges throughout the stability period. The NH-Tween-80 revealed 191.22 μg/mL of ADP permeation through Strat-M® membrane which was statistically significant ( p &lt; 0.05 ) compared to NH-SLS, NH-glycerol, and control solution. At 24 h, NH-Tween-80 demonstrated 305.11 μg/mL of ADP permeation in Wistar rat abdominal skin which was 1.99-, 1.56-, and 4.89-fold higher in comparison with NH-SLS, NH-glycerol, and control solution, respectively. Moreover, the ex vivo permeability of NH-Tween-80 was also compared with conventional gel (market sample) which was 3.38-fold greater at 24 h. During the 6th month of accelerated stability analysis, the NH-Tween-80, NH-SLS, and NH-glycerol demonstrated 99.25 % ± 0.15 , 91.23 % ± 0.41 , and 96.08 % ± 0.20 drug content, respectively. There were no noticeable physical changes observed up to 6 months for NH-Tween-80, while color change was observed in the 1st month and 3rd month of accelerated stability samples of NH-SLS and NH-glycerol, respectively. In this study, only NH-Tween-80 was considered both physically and chemically stable formulation. Therefore, it was concluded that the topical application of ADP-NH containing Tween-80 could be a very promising alternative for the treatment of acne vulgaris.</jats:p

Mean-Payoff Optimization in Continuous-Time Markov Chains with Parametric Alarms

Continuous-time Markov chains with alarms (ACTMCs) allow for alarm events that can be non-exponentially distributed. Within parametric ACTMCs, the parameters of alarm-event distributions are not given explicitly and can be subject of parameter synthesis. An algorithm solving the $\varepsilon$-optimal parameter synthesis problem for parametric ACTMCs with long-run average optimization objectives is presented. Our approach is based on reduction of the problem to finding long-run average optimal strategies in semi-Markov decision processes (semi-MDPs) and sufficient discretization of parameter (i.e., action) space. Since the set of actions in the discretized semi-MDP can be very large, a straightforward approach based on explicit action-space construction fails to solve even simple instances of the problem. The presented algorithm uses an enhanced policy iteration on symbolic representations of the action space. The soundness of the algorithm is established for parametric ACTMCs with alarm-event distributions satisfying four mild assumptions that are shown to hold for uniform, Dirac and Weibull distributions in particular, but are satisfied for many other distributions as well. An experimental implementation shows that the symbolic technique substantially improves the efficiency of the synthesis algorithm and allows to solve instances of realistic size.Comment: This article is a full version of a paper accepted to the Conference on Quantitative Evaluation of SysTems (QEST) 201

Optimizing Performance of Continuous-Time Stochastic Systems using Timeout Synthesis

We consider parametric version of fixed-delay continuous-time Markov chains (or equivalently deterministic and stochastic Petri nets, DSPN) where fixed-delay transitions are specified by parameters, rather than concrete values. Our goal is to synthesize values of these parameters that, for a given cost function, minimise expected total cost incurred before reaching a given set of target states. We show that under mild assumptions, optimal values of parameters can be effectively approximated using translation to a Markov decision process (MDP) whose actions correspond to discretized values of these parameters