Efficacy Screening Research Articles

Phenalen-1-One-Mediated Antimicrobial Photodynamic Therapy and Chlorhexidine Applied to a Novel Caries Biofilm Model

Antimicrobial photodynamic therapy (aPDT) may be useful as a supportive antimicrobial measure for caries-active subjects. In this study, the antimicrobial efficacy of aPDT with a phenalen-1-one photosensitizer was evaluated in a novel in vitro biofilm model comprising Actinomyces naeslundii, Actinomyces odontolyticus, and Streptococcus mutans and was compared to chlorhexidine. The proposed biofilm model allows high-throughput screening for antimicrobial efficacy while exhibiting a differentiated response to different antimicrobial approaches. While chlorhexidine 0.2% showed a reduction of ≈4 log₁₀ for all species, aPDT led to a more pronounced reduction of S. mutans (2.8 log₁₀) than of Actinomyces spp. (1.2 or 1.3 log₁₀). A similar effect was also observed in monospecies biofilms. Therefore, aPDT may be more effective against S. mutans than against Actinomyces spp. when in biofilms, and this antimicrobial approach merits further investigations.

The Rat Gambling Task as a model for the preclinical development of treatments for gambling disorder

ABSTRACTGambling is a harmless pastime for many, but for some it can become problematic with serious social and financial consequences. To date, no pharmacological treatments for gambling disorder have been approved. Progress in this regard is undoubtedly hampered by the lack of established preclinical models that allow for the screening of the potential efficacy of new approaches. The Rat Gambling Task (rGT), based on the Iowa Gambling Task in humans, is a model of some of the decision-making processes involved in gambling. The purpose of the present review is to summarize the literature to date on the use of the rGT for preclinical testing of pharmacological agents. First, the rGT is described and compared to the IGT. Next, validity is examined to establish the rGT as a viable model for preclinical evaluation of new drugs. Finally, the available data on the effects of pharmacological challenges on the rGT are reviewed focusing on dopamine, norepinephrine, serotonin and opioid systems. It is concluded that the rGT may provide a viable preclinical model for new drug development for the treatment of gambling.

Encountering epidemic effects of leaf spot disease (Alternaria brassicae) on Aloe vera by fungal biocontrol agents in agrifields-An ecofriendly approach.

Aloe vera (L.) Burm.f. is a highly important and extensively cultivated medicinal plant and that is also extensively used in the cosmetic industry. It has been frequently reported to suffer from Alternaria leaf spot disease in various parts of the world. Various fungicides used to combat this disease, have deleterious effects on the environment and on pharmacologically important constituents of Aloe vera. To avoid the harmful effects of fungicides an ecofriendly approach has been adopted here. A weekly survey was conducted during 2013–2015 in and around North 24 Parganas (West Bengal) to obtain the percentage of disease index (PDI). For biological control of the disease, screening of the antagonistic efficacy of biocontrol agents was carried out through the in vitro dual-culture-plate method and scanning electron microscopy (SEM) was used to study the mechanism. The in vitro effects of fungicides on the radial growth of the pathogen were evaluated through the poison food method and were compared with potent antagonistic fungi. Field application of potent antagonistic fungi was conducted through the dip-and-spray method. The results showed that, the PDI peaked during the hot and humid conditions of May to September (76.57%–98.57%) but decreased during the winter, December-January (35.71–46.66%). Trichoderma asperellum exerted the greatest inhibition of the radial growth of A. brassicae acting through non volatile (70.39%) and volatile metabolites (72.17%). A SEM study confirmed the hyperparasitic nature of T. asperellum through hyphal coiling-T. asperellum was similar to 2% blitox-50 (73.92%) and better than 2% bavistin (59.77%) (in vitro). In agricultural field trials (2013–15), Trichoderma application restricted the disease to the smallest area (PDI 24.00–29.33%) in comparison to untreated plots (73.33%). In conclusion, saplings treated with the dip method (108 spores / mL) and sprayed 4 times with a spore suspension of biocontrol agents such as T. asperellum, T. viride and T. harzianum, standardized at a rate of 2.5 L / plot (36 sq ft) (108 spores/ mL) are suggested for the ecofriendly management of this epidemic leaf spot disease of Aloe vera in agricultural fields.

In Vitro Tissue Microarrays for Quick and Efficient Spheroid Characterization

Three-dimensional (3D) in vitro microphysiological cultures, such as spheroids and organoids, promise increased patient relevance and therapeutic predictivity compared with reductionist cell monolayers. However, high-throughput characterization techniques for 3D models are currently limited to simplistic live/dead assays. By sectioning and staining in vitro microtissues, researchers can examine their structure; detect DNA, RNA, and protein targets; and visualize them at the level of single cells. The morphological examination and immunochemistry staining for in vitro cultures has historically been done in a laborious manner involving testing one set of cultures at a time. We have developed a technology to rapidly screen spheroid phenotype and protein expression by arranging 66 spheroids in a gel array for paraffin embedding, sectioning, and immunohistochemsitry. The process is quick, mostly automatable, and uses 11 times less reagents than conventional techniques. Here we showcase the capabilities of the technique in an array made up of 11 different cell lines stained in conventional hematoxylin and eosin (H&E) staining, as well as immunohistochemistry staining for estrogen (ER), progesterone (PR), and human epidermal growth factor (Her-2) receptors, and TP53. This new methodology can be used in optimizing stem cell–based models of disease and development, for tissue engineering, safety screening, and efficacy screens in cancer research.

Ternary copper(II) complex: NCI60 screening, toxicity studies, and evaluation of efficacy in xenograft models of nasopharyngeal carcinoma.

Copper(II) ternary complex, [Cu(phen)(C-dmg)(H2O)]NO3 was evaluated against a panel of cell lines, tested for in vivo efficacy in nasopharyngeal carcinoma xenograft models as well as for toxicity in NOD scid gamma mice. The Cu(II) complex displayed broad spectrum cytotoxicity against multiple cancer types, including lung, colon, central nervous system, melanoma, ovarian, and prostate cancer cell lines in the NCI-60 panel. The Cu(II) complex did not cause significant induction of cytochrome P450 (CYP) 3A and 1A enzymes but moderately inhibited CYP isoforms 1A2, 2C9, 2C19, 2D6, 2B6, 2C8 and 3A4. The complex significantly inhibited tumor growth in nasopharyngeal carcinoma xenograft bearing mice models at doses which were well tolerated without causing significant or permanent toxic side effects. However, higher doses which resulted in better inhibition of tumor growth also resulted in toxicity.

Screening of BCG Vaccine Efficacy among Healthy Vaccinated Adults in Khartoum, Sudan

Tuberculosis (TB) is a major global health problem. The BCG is an attenuated vaccine. Tuberculin test is used as a nonspecific TB vaccination indicator. This study was aimed to determine the efficacy of BCG vaccine through screening of healthy, vaccinated adults’ subjects in Khartoum. A total of one hundred (n=100) healthy and TB symptoms free participants were screened by manteaux test. The participants were involving 55 (55%) males and 45 (45%) female. All participants were over 20 years and most of them had a scar in their vaccination site. All participants were screened through injection of purified protein derivative PPD (only 0.1 mL) intra-dermally into their volar forearm then 48-72 post-injection their induration diameter was measured. The results showed that out one hundred (n=100) participants, only 39 (39%) were positive for Manteaux test (≥ 10 mm diameter), while 61 (61%) were negative (≥ 10 mm diameter). Among the 39 positives, 33 show reading between 10 mm to 15 mm and 6 of them show zone ≥ 15 mm. In the other hand 53 out of 61 tuberculin test negative participants showed no induration post PPD injection and the rest were shows reading zone between 5 to 9 mm. The result shows that among the 39 positive participants 23 (58.97%) were male while only 16 (41.03%) were female. The mean of zone reading among the positive participants is higher in male 13.96 ± 3.29 than female 13.81 ± 2.22. The study concluded that more than half of the participants were negative for tuberculin test and this may be interpreted by either the vaccine was invalid or their cell-mediated immunity against TB is reduced. The discrepancy in the zone reading means between male and female may be related to some physiological difference. Further studies with more sample size and by using a more advanced technique (IFNγ) should be done to clarify the results.

Antisense Oligonucleotide Targeting of 3'-UTR of mRNA for Expression Knockdown.

With the recent conditional approval of an antisense oligonucleotide (AON) that restores the reading frame of DMD transcript in a subset of Duchenne muscular dystrophy patients, it has been established that AONs sharing similar chemistry have clear clinical potential. Genetic diseases, such as facioscapulohumeral dystrophy (FSHD), can be the result of gain-of-function mutations. Since mRNA processing in terms of termination of transcription, its transport from the nucleus to the cytoplasm, its stability and translation efficiency are dependent on key 3'UTR elements, it follows that targeting theseelements with AONs have the potential to induce gene silencing. Aberrant expression of the Double homeobox 4 (DUX4) transcription factor and the downstream consequences of such expression is the hallmark of FSHD. Here we describe the bioinformatic strategies behind the design of AONs targeting polyadenylation signals and the methodologies relevant to their in vitro screening for efficacy and safety, including analysis of expression at the transcript and protein level of the specific target and downstream genes, and measurement of the effect on the fusion index of myotubes. The targeting of permissive DUX4 and MSTN are used as examples. MSTN encodes for myostatin, a negative regulator of myogenesis; the downregulation of MSTN expression has the potential to address the muscular atrophy associated with muscular dystrophies, sarcopenia, cancer and acquired immunodeficiency syndrome.

Soybean Aphid Efficacy Screening Program, 2017

Soybean Aphid Efficacy Screening Program, 2017

Development of the Digital Arthritis Index, a Novel Metric to Measure Disease Parameters in a Rat Model of Rheumatoid Arthritis.

Despite a broad spectrum of anti-arthritic drugs currently on the market, there is a constant demand to develop improved therapeutic agents. Efficient compound screening and rapid evaluation of treatment efficacy in animal models of rheumatoid arthritis (RA) can accelerate the development of clinical candidates. Compound screening by evaluation of disease phenotypes in animal models facilitates preclinical research by enhancing understanding of human pathophysiology; however, there is still a continuous need to improve methods for evaluating disease. Current clinical assessment methods are challenged by the subjective nature of scoring-based methods, time-consuming longitudinal experiments, and the requirement for better functional readouts with relevance to human disease. To address these needs, we developed a low-touch, digital platform for phenotyping preclinical rodent models of disease. As a proof-of-concept, we utilized the rat collagen-induced arthritis (CIA) model of RA and developed the Digital Arthritis Index (DAI), an objective and automated behavioral metric that does not require human-animal interaction during the measurement and calculation of disease parameters. The DAI detected the development of arthritis similar to standard in vivo methods, including ankle joint measurements and arthritis scores, as well as demonstrated a positive correlation to ankle joint histopathology. The DAI also determined responses to multiple standard-of-care (SOC) treatments and nine repurposed compounds predicted by the SMarTRTM Engine to have varying degrees of impact on RA. The disease profiles generated by the DAI complemented those generated by standard methods. The DAI is a highly reproducible and automated approach that can be used in-conjunction with standard methods for detecting RA disease progression and conducting phenotypic drug screens.

Abstract 20919: Manipulation-Free Particle Image Velocimetry Method of Screening Drugs Using Human iPSC-Derived Cardiomyocytes

Introduction: Currently available drug screening models are not efficient in detecting cardiac toxicity. Here we demonstrate the in vitro Particle Image Velocimetry (PIV) assays followed by fourier spectrum and heatmap analyses for measuring the impact of different cardiac drugs on the spontaneous beat frequency (SBF) and spontaneous beat amplitude (SBA) of beating cardiomyocytes (CMCs). Hypothesis: Our PIV method of measuring CMCs contractility could be beneficial for drug testing and preclinical screening to detect cardio-toxicity. Methods and Results: The novelty of our system is that we can record the spatiotemporal maturation of human iPSC-derived CMCs at specific positions. We have evaluated the contractility of CMCs with the response to various chemical compounds such as Verapamil (Ca2+ blocker), Isoproterenol (Ca2+ activator), E-4031 (K+ inhibitor) and NS-1643 (K+ activator). Our optically recorded beat patterns were in good agreement with the calcium-imaging signal ( Fig 1 ). Our data also show that Isoproterenol, the β adrenergic agonist influencing intracellular Ca2+ dynamics, induced a substantial and sustained increase in SBF without triggering arrhythmias (Fig 2A, B) . Fourier analysis clearly indicates a shift in the SBF (Fig. 2C , dotted line). Power spectra of consecutive recordings are shown as heat maps ( Fig. 2D ). The reversibility of the Isoproterenol effect is indicated by the SBF returning to the baseline value after drug removal (Fig 2B, E ). Conclusions: We report for the first time the applications of PIV assays for prospective cardiac drug efficacy screening by measuring the contractility of CMCs from the video image without jeopardizing the biology of cells.

A clicking hip in a newborn baby should never be ignored

Screening of the hip in neonates was introduced in the United Kingdom in 1969. The debate on its efficacy, selective versus universal screening, and risk factors, continues. In this month’s issue, a paper from Professor Paton and colleagues provides an analysis of contemporary practice from an

Emerging tumor spheroids technologies for 3D in vitro cancer modeling.

Cancer is a leading cause of mortality and morbidity worldwide. Around 90% of deaths are caused by metastasis and just 10% by primary tumor. The advancement of treatment approaches is not at the same rhythm of the disease; making cancer a focal target of biomedical research. To enhance the understanding and prompts the therapeutic delivery; concepts of tissue engineering are applied in the development of in vitro models that can bridge between 2D cell culture and animal models, mimicking tissue microenvironment. Tumor spheroid represents highly suitable 3D organoid-like framework elucidating the intra and inter cellular signaling of cancer, like that formed in physiological niche. However, spheroids are of limited value in studying critical biological phenomenon such as tumor-stroma interactions involving extra cellular matrix or immune system. Therefore, a compelling need of tailoring spheroid technologies with physiologically relevant biomaterials or in silico models, is ever emerging. The diagnostic and prognostic role of spheroids rearrangements within biomaterials or microfluidic channel is indicative of patient management; particularly for the decision of targeted therapy. Fragmented information on available in vitro spheroid models and lack of critical analysis on transformation aspects of these strategies; pushes the urge to comprehensively overview the recent technological advancements (e.g. bioprinting, micro-fluidic technologies or use of biomaterials to attain the third dimension) in the shed of translationable cancer research. In present article, relationships between current models and their possible exploitation in clinical success is explored with the highlight of existing challenges in defining therapeutic targets and screening of drug efficacy.

Contactless Particle Image Velocimetry (PIV) Method of Screening Drugs Using Human iPSC-derived Cardiomyocytes

Introduction: The development of cardiac arrhythmias as a pharmacological side effect has become the single most common cause of the withdrawal or restriction of previously marketed drugs. Currently available drug screening models are not efficient in detecting cardiac toxicity. Here we demonstrate in vitro Particle Image Velocimetry (PIV) assays followed by fourier spectrum and heatmap analyses for measuring the impact of different cardiac drugs on the rate and frequency of beating cardiomyocytes (CMCs). Hypothesis: Our PIV method of measuring CMCs contractility could be beneficial for drug testing, preclinical screening to detect cardio toxicity without jeopardizing the biology of cells. Methods and Results: The novelty of our system is that we can record the spatiotemporal maturation of human iPSC-derived CMCs at specific positions. We have evaluated the contractility of CMCs with the response to various chemical compounds such as Verapamil (Ca2+ channel blocker), Isoproterenol (Ca2+ channel activator), E-4031 (K+ channel inhibitor) and NS-1643 (K+ channel activator). Our data shows that the chronotropic effect of verapamil and E-4031 at the concentration of 1 μM and 500 nM respectively, has significantly reduced the beating frequency. Similarly, the chronotropic effect of Isoproterenol and NS-1643 at the concentration of 1 μM and 60 nM respectively, has meaningfully increased the beating frequency. Moreover, our fourier spectrum and heatmap analyses further confirmed the spatiotemporal changes occur due to the addition of chronotropic drugs. Conclusions: We report for the first time the applications of PIV assays for prospective cardiac drug efficacy screening by measuring the contractility of CMCs from the video image without jeopardizing the biology of cells.

An Update to Changing Patterns of Anal Carcinoma in the United States

Approximately 8,200 new cases (2,950 males; 5,250 females) of anal carcinoma will be diagnosed in the United States in 2017. Specifically, anal squamous cell carcinoma accounts for about 70% of all anal cancers in the US and is associated with human papillomavirus (HPV) and human immunodeficiency virus (HIV) infections. As cancer prevention and treatments have evolved over time, medical management of HIV has improved, and sexual behaviors have changed, anal carcinoma incidence rates may have also changed. The Surveillance, Epidemiology, and End Results (SEER) database was used to identify and determine incidence rates for 6,607 men and 5,729 women diagnosed with anal cancer from 1973-2013. Carcinoma in situ (CIS) and invasive disease (SCC), as defined by the SEER historical stage category, were analyzed separately. Joinpoint regression models identified time points at which histology-specific incidence trends changed. Age-adjusted incidence rate changes over time are expressed as annual percent changes (APC), which represent the log-transformed slopes across time. Joinpoint regression was performed using the Joinpoint software program (v4.3.1.0) and all other analyses were performed using SEER*Stat software (v8.3.2) and Stata/SE (v13.1). Results: Joinpoint analyses identified 1994 and 2011 as the inflection points at which combined anal CIS and SCC average annual incidence rates shifted most markedly among 12,336 patients from 1973-2013. The slope of incidence rates recently decreased (2011, 95% CI 2008-2011; APC -4.92, 95% CI -16.8 to 8.6). Separate joinpoint analyses were conducted for noninvasive disease (CIS) and invasive cancer (SCC). Although men and women were more likely to present with CIS (risk ratio [RR] 1.51, 95% CI 1.45-1.59) after 2011, the slope of incidence rates for CIS have statistically decreased (2010, 95% CI 2008-2011; APC -6.96, 95% CI -13.3 to -0.2), especially for men (2010, 95% CI 2007-2011, APC -9.25, 95% CI -16.0 to -1.9). Moreover, both men and women were less likely to present with localized (RR 0.81, 95% CI 0.76-0.87), regional (RR 0.69, 95% CI 0.63-0.76), and distant SCC (RR 0.89, 95% CI 0.75-1.06). During 2011-2013, men were more likely to present with CIS (RR 2.58, 95% CI 2.34-2.86) but less likely to present with localized (RR 0.46, 95% CI 0.41 - 0.53), regional (RR 0.41, 95% CI 0.34 - 0.49), and distant SCC (RR 0.37, 95% CI 0.26 - 0.51) compared to women. The later time period also included younger age at diagnosis. Anal cancer incidence rates have decreased since 2011. Moreover, patients are more likely to present with CIS than invasive disease at any stage, and this trend is more pronounced in men. These changes in anal carcinoma patterns may reflect improved HIV management, increased use of barrier protection for men, and efficacious screening and management of anal squamous intraepithelial lesions.

An integrative microfluidic chip for combined compound separation and enhanced biological activity and efficacy screening

Cylindrospermopsin (CYN) was found to occur in Portugal for the first time. In this study CYN values varied from a minimum of 1.4 μg L−1 to a maximum of 12 μg L−1 detected through HPLC technique and confirmed by LC-MS method. Amplification of the cyrC gene was done and was confirmed to be from the genera Aphanizomenon. This study is therefore an important contribution to the knowledge on the dispersal and biogeography of CYN.

Evaluating FINDRISC as a screening tool for type 2 diabetes among overweight adults in the PREVIEW:NZ cohort

AimsThis study aimed to evaluate the efficacy of a high (≥12) Finnish diabetes risk (FINDRISC) score in identifying undiagnosed prediabetes and type 2 diabetes (T2D) in an New Zealand population of overweight and obese individuals, across a variety of ethnic groups. MethodsWe estimated the efficacy of elevated FINDRISC scores in predicting prediabetes and T2D in 424 overweight adults with no prior diagnosis recruited for the PREVention of diabetes through lifestyle Interventions in Europe and Worldwide (PREVIEW) study. All participants who completed the FINDRISC questionnaire during a pre-screening phase with a score of ≥12 were then screened using a 2h oral glucose tolerance test (2h-OGTT) to identify undiagnosed dysglycaemia. ResultsOf the 424 participants, 65% (n=280) were pre-diabetic and 7% (n=32) had undiagnosed T2D. A higher FINDRISC score was significantly associated with prediabetes and T2D (P=0.02). There was a significant association between ethnicity and glycaemic status (normal vs prediabetes/T2D, P=0.02). Increasing the FINDRISC cut-off to ≥15 resulted in a non-significant increase in the proportion of participants correctly classified with dysglycaemia. ROC-AUC=0.6 with sensitivity=0.6026 (95% CI: 0.5459–0.6573) and specificity=0.5536 (95% CI: 0.4567–0.6476). Isolated impaired fasting glucose (IFG) was more efficient in predicting dysglycaemia than isolated impaired glucose tolerance (IGT). ConclusionsThe FINDRISC questionnaire is a useful and efficacious screening tool to identify unknown prediabetes and T2D in overweight New Zealanders, particularly in Maori individuals.

Return of the lysergamides. Part IV: Analytical and pharmacological characterization of lysergic acid morpholide (LSM-775).

Lysergic acid diethylamide (LSD) is perhaps one of the best-known psychoactive substances and many structural modifications of this prototypical lysergamide have been investigated. Several lysergamides were recently encountered as 'research chemicals' or new psychoactive substances (NPS). Although lysergic acid morpholide (LSM-775) appeared on the NPS market in 2013, there is disagreement in the literature regarding the potency and psychoactive properties of LSM-775 in humans. The present investigation attempts to address the gap of information that exists regarding the analytical profile and pharmacological effects of LSM-775. A powdered sample of LSM-775 was characterized by X-ray crystallography, nuclear magnetic resonance spectroscopy (NMR), gas chromatography mass spectrometry (GC-MS), high mass accuracy electrospray MS/MS, high performance liquid chromatography (HPLC) diode array detection, HPLC quadrupole MS, and GC solid-state infrared analysis. Screening for receptor affinity and functional efficacy revealed that LSM-775 acts as a nonselective agonist at 5-HT1A and 5-HT2A receptors. Head twitch studies were conducted in C57BL/6J mice to determine whether LSM-775 activates 5-HT2A receptors and produces hallucinogen-like effects in vivo. LSM-775 did not induce the head twitch response unless 5-HT1A receptors were blocked by pretreatment with the antagonist WAY-100,635 (1mg/kg, subcutaneous). These findings suggest that 5-HT1A activation by LSM-775 masks its ability to induce the head twitch response, which is potentially consistent with reports in the literature indicating that LSM-775 is only capable of producing weak LSD-like effects in humans.

Combination of MALDI-MSI and cassette dosing for evaluation of drug distribution in human skin explant.

Study of skin penetration and distribution of the drug compounds in the skin is a major challenge in the development of topical drug products for treatment of skin diseases. It is crucial to have fast and efficacious screening methods which can provide information concerning the skin penetration and the distribution of the drug molecules in the region of the target. Mass spectrometry imaging (MSI) such as matrix-assisted laser desorption/ionization (MALDI)-MSI offers the opportunity to analyze the drug distribution at micrometer scale, but is a low throughput technique. Cassette dosing of drug molecules has been widely used for two decades as a high throughput screening tool for plasma pharmacokinetic analysis. The purpose of this study is to evaluate the utility of combining MALDI-MSI with cassette dosing to obtain a medium throughput screening technique for drug distribution in the skin directly from thin tissue sections. Excised fresh human skin was treated with two different formulation types containing both single drugs and a cassette with four drugs. Biopsies were taken and analyzed with traditional UHPLC-MS/MS and MALDI-MSI. The results reveal that skin penetration data of the four drugs administered together were in agreement with skin penetration data obtained when the molecules were administered individually. Furthermore, the MALDI-MSI data reveal different distribution profiles of the four drugs which were not possible to deduce from the UHPLC-MS/MS bioanalysis. These findings suggest that combination of MALDI-MSI and cassette dosing can be used as a medium throughput screening tool at an early stage in the drug discovery/development process. Graphical abstract Investigation of drug distribution in human skin explant by MALDI-MSI after cassette dosing.

Abstract 810: Establishing patient derived preclinical in vitro and in vivo models of pediatric brain cancers

Abstract The recent surge in understanding genomic aberrations of some of the deadliest childhood brain cancers has highlighted the need for robust preclinical models. Such models will allow for robust drug screening and preclinical evaluation of efficacy, toxicity, and tumor penetrance in vivo. Given the rarity and importance of patient derived specimens, handling and processing methods are perhaps the most critical steps for successful establishment of viable and reproducible in vitro and in vivo models. Since specimen source varies (biopsy, autopsy, or cryo-preserved), processing methods should be refined to allow for optimal extraction of maximum numbers of viable cells from each specimen type. We have developed standardized procedures for handling and processing of tissue samples obtained from biopsy, autopsy, or cryo-preserved specimens as well as necropsy tissue obtained from existing xenograft models. Two processing methods for generating viable cell suspensions are described. The first method, which uses collagenase-DNAse mediated digestion of the tissue is efficient with bulky samples and can be used with tissues obtained at autopsy. The second method uses a commercially available enzymatic dissociation kit optimal for small volume samples such as biopsy, cryo-preserved and mouse necropsy specimens. We show that obtaining viable cell suspension from precious tumor tissue by these methods results in successful generation of pre-clinical in vitro and in vivo models of DIPG, pilocytic astrocytoma and medulloblastoma that represent the exact genetic makeup of the original patient tumor. We further demonstrate intracranial injections of these cells into P2 mice for generating orthotopic xenograft models of brainstem or cortical tumors. Our methods and results allow for rapid establishment of preclinical models using rare and valuable childhood brain tumor specimens. These pre-clinical models serve as valuable tools for understanding the molecular mechanisms of the disease, identifying targetable molecules, and screening of novel therapeutics. Citation Format: Sridevi Yadavilli, Madhuri Kambhampati, Jamila Gittens, Eshini Panditharatna, Mojca Stampar, Lindsay B. Kilburn, Suresh Magge, Roger J. Packer, Javad Nazarian. Establishing patient derived preclinical in vitro and in vivo models of pediatric brain cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 810. doi:10.1158/1538-7445.AM2017-810

Rapid screening of the antimicrobial efficacy of Ag zeolites

A semi-quantitative screening method was used to compare the killing efficacy of Ag zeolites against bacteria and yeast as a function of the zeolite type, crystal size and concentration. The method, which substantially reduced labor, consumables and waste and provided an excellent preliminary screen, was further validated by quantitative plate count experiments. Two pairs of zeolite X and zeolite beta with different sizes (ca. 200nm and 2μm for zeolite X and ca. 250 and 500nm for zeolite beta) were tested against Escherichia coli (E. coli) and Candida albicans (C. albicans) at concentrations in the range 0.05–0.5mgml−1. Reduction of the zeolite crystal size resulted in a decrease in the killing efficacy against both microorganisms. The semi-quantitative tests allowed convenient optimization of the zeolite concentrations to achieve targeted killing times. Zeolite beta samples showed higher activity compared to zeolite X despite their lower Ag content, which was attributed to the higher concentration of silver released from zeolite beta samples. Cytotoxicity measurements using peripheral blood mononuclear cells (PBMCs) indicated that Ag zeolite X was more toxic than Ag zeolite beta. However, the trends for the dependence of cytotoxicity on zeolite crystal size at different zeolite concentrations were different for the two zeolites and no general conclusions about zeolite cytotoxicity could be drawn from these experiments. This result indicates a complex relationship, requiring the necessity for individual cytotoxicity measurements for all antimicrobial applications based on the use of zeolites.