A mechanobiological model for tumor spheroid evolution with application to glioblastoma: A continuum multiphysics approach

Background: Spheroids are in vitro quasi-spherical structures of cell aggregates, eventually cultured within a hydrogel matrix, that are used, among other applications, as a technological platform to investigate tumor formation and evolution. Several interesting features can be replicated using this methodology, such as cell communication mechanisms, the effect of gradients of nutrients, or the creation of realistic 3D biological structures. The main objective of this work is to link the spheroid evolution with the mechanical activity of cells, coupled with nutrient consumption and the subsequent cell dynamics. Method: We propose a continuum mechanobiological model which accounts for the most relevant phenomena that take place in tumor spheroid evolution under in vitro suspension, namely, nutrient diffusion in the spheroid, kinetics of cellular growth and death, and mechanical interactions among the cells. The model is qualitatively validated, after calibration of the model parameters, versus in vitro experiments of spheroids of different glioblastoma cell lines. Results: Our model is able to explain in a novel way quite different setups, such as spheroid growth (up to six times the initial configuration for U-87 MG cell line) or shrinking (almost half of the initial configuration for U-251 MG cell line); as the result of the mechanical interplay of cells driven by cellular evolution. Conclusions: Glioblastoma tumor spheroid evolution is driven by mechanical interactions of the cell aggregate and the dynamical evolution of the cell population. All this information can be used to further investigate mechanistic effects in the evolution of tumors and their role in cancer disease

Dealing with uncertainty in calibration of a stormwater biofilter model

Uncertainty is a part of every modelling process and is caused by many different sources. Therefore, good and reliable model predictions are often very hard to obtain. Stormwater biofilter models are no exception. For a modeler to reduce uncertainty, first it is necessary to map and understand all the sources of uncertainty and their impact on the modelling processes. This paper is focused on understanding and reduction of uncertainties during calibration process of a model for prediction of treatment efficiency of stormwater biofilters (bioretentions and raingardens). The model was applied to Monash Car Park Biofilter, to simulate removal of atrazine for which removal performance data have been available over 6 simulated storm tests. The model was first calibrated, and then sensitivity analysis has been carried out for the most sensitive model parameters. The results show the key sources of uncertainties and links between them. The predictive uncertainty intervals were constructed, suggesting that the developed model is sound

Stories of dying and death as told by family members’ of Adolescents and Young Adults (AYAs) who have died from cancer

Research of AYAs with cancer has developed significantly over the last 20 years. The research has demonstrated that AYAs with cancer are a forgotten population, who require closer study in order to understand their unique issues. This paper examines family members’ experiences of adolescents and young adults (AYAs) during the dying stage of their cancer trajectory. The results are drawn from a larger study titled ‘From Go to Woe; Family Members’ Stories of Adolescents and Young People Living with and Dying from Cancer, which storied the family members’ experience of the diagnosis, treatment, dying and death of an AYA family member, utilizing Armstrong-Coster’s (2004) four stages of the cancer trajectory. The principal researcher’s motivation to understand and story these experiences was related to her own isolation and lack of information when her 16 year old son Anthony, was diagnosed with and eventually died of cancer at 17 years of age. The significance of this study is the contribution made to the identification of issues that can inform health policy/ guidelines. The findings have the potential to increase understanding of, and prepare family members and AYAs with cancer, for the experience of the death and dying stage of the cancer trajectory

Assessing Uncertainty of a Biofilter Micropollutant Transport Model MPiRe

MPiRe (Micro-Pollutants In RaingardEns) model was developed to predict both flows and removal of micropollutants by stormwater biofilters. It is a conceptual 1D model that includes sorption/desorption, biodegradation and volatilization processes. This paper presents an uncertainty evaluation of MPiRe using the GLUE methodology with atrazine as a representative pollutant. The uncertainty analysis shows that the soil-water partitioning coefficient (normalized to organic carbon content) is the most sensitive model parameter, while there is some correlation between sorption parameters and high uncertainty in the degradation rate estimation. It is hypothesized that the correlation between sorption parameters can be diminished by choosing two different combinations of calibration parameters (e.g. variations of their mutual products), and this hypothesis will be further tested. The practical implication of this analysis is that particular care should be given to measurements of initial outflow concentrations of events (to decrease the uncertainty in the degradation rate estimation). Additionally, if it is necessary to prioritize between monitoring procedures, the most attention should be given to sorption kinetics.</p

Phenolic Content, and Antioxidant and Antimicrobial Activities of Crataegus Oxyacantha L (Rosaceae) Fruit Extract from Southeast Serbia

Purpose: The aim of this work was to determine the content of total phenols, total flavonoids, anthocyanins, as well as antioxidant and antimicrobial activities of hawthorn ( Crataegus oxyacantha L.) alcohol, hydroalcohol and aqueous extracts. Methods: The content of total phenols, flavonoids and anthocyanins of the alcohol, hydroalcohol and aqueous extracts of hawthorn were determined using spectrophotometric methods. Antioxidant assay was based on the measurement of DPPH absorbance at 517 nm caused by the reaction of DPPH with the test sample. Antimicrobial activity was evaluated by measuring the zone of inhibition against selected test microorganisms: Bacillus subtilis , Staphylococcus aureus , Escherichia coli , Pseudomonas aeruginosa , and Salmonella abony while antifungal activity was tested against two organisms: Aspergillus niger and Candida albicans . Results: The results of spectrophotometric investigations indicate that the content of total phenol compounds in the investigated extracts varied from 2.12 to 30.63 mg GAE g-1 of fresh hawthorn sample. The content of anthocyanins ranged from 0.3207 to 3.168 mg of cyanidin-3-O-glucoside g-1 of fresh hawthorn fruit. The fruit extracts showed high antioxidant activity with DPPH radical transformation value as high as 89.9 % in the methanol-water (50/50, v/v%)) extract. The ethanol extract exhibited antimicrobial activity against all test microorganisms except two, Bacillus subtilis and Staphylococcus aureus, and one species of fungi, Aspergillus niger.Flavonoid structure influenced the extract’s selectivity towards Gram-positive and Gram negative bacteria. Conclusion: Extracts of the fruit of Crataegus oxyacantha L. can be used as natural antioxidant and antimicrobial preparations

Phenolic Content, and Antioxidant and Antimicrobial Activities of Crataegus Oxyacantha L (Rosaceae) Fruit Extract from Southeast Serbia

Total phenolic and flavonoid contents of different extracts of Papaver rhoeas L. were examined. High contents of total phenolic compounds (9.73 -19.91 mg GAE/g of fresh petals) and total flavonoids (7.904 -11.45 mg QE/g of fresh petals) were determined. Red pigment present in the flowers of P. rhoeas L. originates from anthocyanins, which may act as natural antioxidants. Anthocyanins content in the investigated extracts is very unified and ranged from 4.72 to 5.193 mg of cyanidin-3-O-glukoside/g of fresh petals. The antioxidant activity of different extracts was tested using the spectrophotometric method by means of the ability of extracts to scavenge stable 1,1-Diphenyl-2-picrylhydrazyl (DPPH). All tested extracts exhibited strong scavenging activity against DPPH radicals, that is higher then 80%. Total phenolic and flavonoid contents may be related to the percentages of the scavenging activity of DPPH assay (estimated correlation coefficient are R 2 = 0.965 and 0.752, respectively). The ethanol extract of P. rhoeas L. showed antimicrobial activity against the yeast Candida albicans, and all tested bacteria except Bacillus subtilis. This paper suggests that the investigated extracts of plant P. rhoes L. could be potentially applied as an antioxidant and antimicrobial agents. Key words: Papaver rhoeas L., phenolic content, anthocyanins content, flavonoid content, antioxidant activity, antibacterial activity. INTRODUCTION Papaver rhoeas L. (Papaveraceae) is an annual herb indigenous to numerous regions in the world. In traditional medicine until synthetic drugs are developed, extracts of this plant have been used for the treatment of a wide range of diseases including inflammation, diarrhea, sleep disorders and, moreover, for cough, analgesia and also the reduction of withdrawal signs of the opioid addiction. It is also claimed that plant P. rhoeas exhibits sedative, narcotic, and emollient effects ( In the present paper, the evaluation of P. rhoeas L. from Southeast Serbia with respect to phenolic content and the antioxidant data of different extracts obtained from plant petals are reported. As it is stated earlier, numerous polyphenols are known to possess excellent antioxidant effects, especially in vitro, and the amount of total polyphenols present in a plant has been suggested to correlate with the antioxidant activity. Therefore, this work represents the first report on phenolic content and related antioxidant activity of the extracts of P. rhoeas L. from Southeast Serbia. Antimicrobial activity of ethanol extract of P. rhoeas was investigated, too. EXPERIMENTAL Plant material The plant was collected at bloom stage in few villages from the South-eastern Cape Province of Serbia in July, 2009. The plant was firstly identified by its vernacular name and later validated by voucher number of the deposited herbarium specimens at the Department of Botany (University of Novi Sad, Serbia). Preparation of plant extracts The fresh petals of P. rhoeas L. were milled by an appropriate blender. Three samples (each weighed 2.0 g) were separated from the previously homogenized plant material, and extracted with the desired volumes (30, 20 and 20 ml, respectively) of the chosen solvents (methanol, ethanol, methanol-water mixture, ethanol-water mixture and water) three times in the further course. Samples were mixed in an ultrasound bath during the extraction procedure. Such obtained extracts were filtered using the Buchner funnel and Whatman No. 1 filter paper. Solid residues were rinsed for several times in order to gain transparent extracts. Finally, the obtained plant extracts were collected in graduated flask of the same volume of 100 ml. Chemicals and reagents 1,1-Diphenyl-2-picrylhydrazyl (DPPH), quercetin and AlCl3 were purchased from Sigma Chemical Co. (St. Louis, MO, USA). FolinCiocalteu&apos;s phenol reagent and sodium carbonate were purchased from Merck Chemical Suppliers (Darmstadt, Germany). Sodium chlorate buffer (pH 1.0) and acetate buffer (pH 4.5) were purchased from the same producer. The other used chemicals including solvents were of analytical grade. Determination of the total phenolics Total phenolic contents in the extracts were determined by the modified Folin-Ciocalteu method Determination of the total monomeric anthocyanins The total monomeric anthocyanin content in the plant extracts was determined using the pH-differential method previously described by (1) Content of the monomeric antocyanin pigment (MAP) was calculated by Equation 2

Enabling cell recovery from 3D cell culture microfluidic devices for tumour microenvironment biomarker profiling

The tumour microenvironment (TME) has recently drawn much attention due to its profound impact on tumour development, drug resistance and patient outcome. There is an increasing interest in new therapies that target the TME. Nonetheless, most established in vitro models fail to include essential cues of the TME. Microfluidics can be used to reproduce the TME in vitro and hence provide valuable insight on tumour evolution and drug sensitivity. However, microfluidics remains far from well-established mainstream molecular and cell biology methods. Therefore, we have developed a quick and straightforward collagenase-based enzymatic method to recover cells embedded in a 3D hydrogel in a microfluidic device with no impact on cell viability. We demonstrate the validity of this method on two different cell lines in a TME microfluidic model. Cells were successfully retrieved with high viability, and we characterised the different cell death mechanisms via AMNIS image cytometry in our model

Suturas mecânicas

The authors review the use of staplers in General Surgery, mainly in Gastroenterological Surgery highlighting safety and effectiveness. They emphasize that the mechanic anastomosis are a viable technique and in some conditions, the best way to perform the anastomosis. The use of staplers makes surgery faster and easier and complications are, generally related to surgeon's experience in using them. Although its costs are higher compared to handsewn suture, it can make the patient total cost lower

Optimizing the enzymatic release of MMAE from isoDGR-based small molecule drug conjugate by incorporation of a GPLG-PABC enzymatically cleavable linker

Antibody-Drug Conjugates (ADCs) and Small Molecule-Drug Conjugates (SMDCs) represent successful examples of targeted drug-delivery technologies for overcoming unwanted side effects of conventional chemotherapy in cancer treatment. In both strategies, a cytotoxic payload is connected to the tumor homing moiety through a linker that releases the drug inside or in proximity of the tumor cell, and that represents a key component for the final therapeutic effect of the conjugate. Here, we show that the replacement of the Val-Ala-p-aminobenzyloxycarbamate linker with the Gly-Pro-Leu-Gly-p-aminobenzyloxycarbamate (GPLG-PABC) sequence as enzymatically cleavable linker in the SMDC bearing the cyclo[DKP-isoDGR] alpha V beta(3) integrin ligand as tumor homing moiety and the monomethyl auristatin E (MMAE) as cytotoxic payload led to a 4-fold more potent anti-tumoral effect of the final conjugate on different cancer cell lines. In addition, the synthesized conjugate resulted to be significantly more potent than the free MMAE when tested following the "kiss-and-run" protocol, and the relative potency were clearly consistent with the expression of the alpha V beta(3) integrin receptor in the considered cancer cell lines. In vitro enzymatic cleavage tests showed that the GPLG-PABC linker is cleaved by lysosomal enzymes, and that the released drug is observable already after 15 min of incubation. Although additional data are needed to fully characterize the releasing capacity of GPLG-PABC linker, our findings are of therapeutic significance since we are introducing an alternative to other well-established enzymatically sensitive peptide sequences that might be used in the future for generating more efficient and less toxic drug delivery systems