Preclinical screening of histone deacetylase inhibitors combined with ABT-737, rhTRAIL/MD5-1 or 5-azacytidine using syngeneic Vk*MYC multiple myeloma

Multiple myeloma (MM) is an incurable malignancy with an unmet need for innovative treatment options. Histone deacetylase inhibitors (HDACi) are a new class of anticancer agent that have demonstrated activity in hematological malignancies. Here, we investigated the efficacy and safety of HDACi (vorinostat, panobinostat, romidepsin) and novel combination therapies using in vitro human MM cell lines and in vivo preclinical screening utilizing syngeneic transplanted Vk*MYC MM. HDACi were combined with ABT-737, which targets the intrinsic apoptosis pathway, recombinant human tumour necrosis factor-related apoptosis-inducing ligand (rhTRAIL/MD5-1), that activates the extrinsic apoptosis pathway or the DNA methyl transferase inhibitor 5-azacytidine. We demonstrate that in vitro cell line-based studies provide some insight into drug activity and combination therapies that synergistically kill MM cells; however, they do not always predict in vivo preclinical efficacy or toxicity. Importantly, utilizing transplanted Vk*MYC MM, we report that panobinostat and 5-azacytidine synergize to prolong the survival of tumor-bearing mice. In contrast, combined HDACi/rhTRAIL-based strategies, while efficacious, demonstrated on-target dose-limiting toxicities that precluded prolonged treatment. Taken together, our studies provide evidence that the transplanted Vk*MYC model of MM is a useful screening tool for anti-MM drugs and should aid in the prioritization of novel drug testing in the clinic.     

Studies on the paradox of seedling rarity in Vaccinium myrtillus L. in NE Scotland

Summary

On the moors studied Vaccinium myrtillus produced many berries containing highly viable seed, yet seedlings were rare. Offtake of berries by birds or mammalian herbivores was apparently minor, most berries simply falling from the bushes when ripe. Fallen berries quickly disappeared, probably being removed by small rodents. Berries were fed experimentally to captive field voles and capercaillies, and it was found that only c. 1% of the seeds survived. For the voles, most of these viable seeds probably resulted from contamination of the droppings with partially-eaten berries or discarded extracted seeds, processes which must contribute to dispersal in the wild. The soil seed-bank was shown to be small, and the viability of buried seed declined from c. 90% to c. 20% in 3 years, due to decay in the soil H horizon and premature germination in the litter layer. Fewer seedlings established from experimental sowings on grass and Vaccinium myrtillus turf than on bare peat. We conclude that Vaccinium myrtillus has a seed-dispersal strategy which secures some long-distance movement by frugivores at the expense of much lost seed, and that the small seed-bank and low numbers of seedlings result from poor defence of the seeds and weak competitive ability of the seedlings; other attributes of Vaccinium myrtillus, e.g. efficient vegetative reproduction, compensate for these losses and enable it to be a successful species.     

Impact of Obesity on Pregnancy Outcome in Different Ethnic Groups: Calculating Population Attributable Fractions

Objectives

To quantify the proportion of adverse pregnancy outcome attributable to maternal obesity.

Design

Cross sectional analysis of routine obstetric dataset.

Setting

Guy’s and St Thomas’s NHS Foundation Trust (GSTFT).

Population

23,668 women who had singleton deliveries at GSTFT between 2004 and 2008.

Methods

Logistic regression was used to estimate the association between BMI and outcome in different ethnic groups. Adjusted odds ratios, and the proportions of obese women, were used to calculate population attributable risk fractions (PAFs).

Main Outcome Measures

(i) Maternal outcomes: diabetes, type of delivery, post-partum haemorrhage, and preterm delivery. (ii) Perinatal outcomes: macrosomia, low birth weight, admission to neonatal intensive care/special care baby unit, and perinatal death.

Results

The prevalence of maternal obesity was 14%. Increasing BMI was independently associated with increasing risk of adverse obstetric and neonatal outcome. At the individual level, the effect of obesity on diabetes was highest in Asian women compared to white women (p for interaction = 0.03). Calculation of population attributable risk fractions demonstrated that one third of diabetes cases and one in six Caesarean sections could be avoided in this population if all obese women were of normal BMI. At the population level, the contribution of obesity to diabetes was highest for Black women (42%), and lowest for oriental women (8%). Seven percent of neonatal macrosomia in all the population, and 13% in Black mothers, were attributable to obesity.

Conclusions

Preventing obesity prior to pregnancy will substantially reduce the burden of obstetric and neonatal morbidity in this population. This reduction will be higher in Black women.     

Determining Immune System Suppression versus CNS Protection for Pharmacological Interventions in Autoimmune Demyelination

A major hallmark of the autoimmune demyelinating disease multiple sclerosis (MS) is immune cell infiltration into the brain and spinal cord resulting in myelin destruction, which not only slows conduction of nerve impulses, but causes axonal injury resulting in motor and cognitive decline. Current treatments for MS focus on attenuating immune cell infiltration into the central nervous system (CNS). These treatments decrease the number of relapses, improving quality of life, but do not completely eliminate relapses so long-term disability is not improved. Therefore, therapeutic agents that protect the CNS are warranted. In both animal models as well as human patients with MS, T cell entry into the CNS is generally considered the initiating inflammatory event. In order to assess if a drug protects the CNS, any potential effects on immune cell infiltration or proliferation in the periphery must be ruled out. This protocol describes how to determine whether CNS protection observed after drug intervention is a consequence of attenuating CNS-infiltrating immune cells or blocking death of CNS cells during inflammatory insults. The ability to examine MS treatments that are protective to the CNS during inflammatory insults is highly critical for the advancement of therapeutic strategies since current treatments reduce, but do not completely eliminate, relapses (i.e., immune cell infiltration), leaving the CNS vulnerable to degeneration.     

Acoustic sequences in non‐human animals: a tutorial review and prospectus

Animal acoustic communication often takes the form of complex sequences, made up of multiple distinct acoustic units. Apart from the well‐known example of birdsong, other animals such as insects, amphibians, and mammals (including bats, rodents, primates, and cetaceans) also generate complex acoustic sequences. Occasionally, such as with birdsong, the adaptive role of these sequences seems clear (e.g. mate attraction and territorial defence). More often however, researchers have only begun to characterise – let alone understand – the significance and meaning of acoustic sequences. Hypotheses abound, but there is little agreement as to how sequences should be defined and analysed. Our review aims to outline suitable methods for testing these hypotheses, and to describe the major limitations to our current and near‐future knowledge on questions of acoustic sequences. This review and prospectus is the result of a collaborative effort between 43 scientists from the fields of animal behaviour, ecology and evolution, signal processing, machine learning, quantitative linguistics, and information theory, who gathered for a 2013 workshop entitled, ‘Analysing vocal sequences in animals’. Our goal is to present not just a review of the state of the art, but to propose a methodological framework that summarises what we suggest are the best practices for research in this field, across taxa and across disciplines. We also provide a tutorial‐style introduction to some of the most promising algorithmic approaches for analysing sequences. We divide our review into three sections: identifying the distinct units of an acoustic sequence, describing the different ways that information can be contained within a sequence, and analysing the structure of that sequence. Each of these sections is further subdivided to address the key questions and approaches in that area. We propose a uniform, systematic, and comprehensive approach to studying sequences, with the goal of clarifying research terms used in different fields, and facilitating collaboration and comparative studies. Allowing greater interdisciplinary collaboration will facilitate the investigation of many important questions in the evolution of communication and sociality.     

Numerical investigations of rib fracture failure models in different dynamic loading conditions

Rib fracture is one of the most common thoracic injuries in vehicle traffic accidents that can result in fatalities associated with seriously injured internal organs. A failure model is critical when modelling rib fracture to predict such injuries. Different rib failure models have been proposed in prediction of thorax injuries. However, the biofidelity of the fracture failure models when varying the loading conditions and the effects of a rib fracture failure model on prediction of thoracic injuries have been studied only to a limited extent. Therefore, this study aimed to investigate the effects of three rib failure models on prediction of thoracic injuries using a previously validated finite element model of the human thorax. The performance and biofidelity of each rib failure model were first evaluated by modelling rib responses to different loading conditions in two experimental configurations: (1) the three-point bending on the specimen taken from rib and (2) the anterior–posterior dynamic loading to an entire bony part of the rib. Furthermore, the simulation of the rib failure behaviour in the frontal impact to an entire thorax was conducted at varying velocities and the effects of the failure models were analysed with respect to the severity of rib cage damages. Simulation results demonstrated that the responses of the thorax model are similar to the general trends of the rib fracture responses reported in the experimental literature. However, they also indicated that the accuracy of the rib fracture prediction using a given failure model varies for different loading conditions.     

A computational framework to investigate retinal haemodynamics and tissue stress

Biomechanics and Modeling in Mechanobiology - The process of vision begins in the retina, yet the role of biomechanical forces in the retina is relatively unknown and only recently being explored....     

Atmospheric photochemical transformations enhance 1,3-butadiene-induced inflammatory responses in human epithelial cells: The role of ozone and other photochemical degradation products

Chemistry of hazardous air pollutants has been studied for many years, yet little is known about how these chemicals, once reacted within urban atmospheres, affect healthy and susceptible individuals. Once released into the atmosphere, 1,3-butadiene (BD) reacts with hydroxyl radicals and ozone (created by photochemical processes), to produce many identified and unidentified products. Once this transformation has occurred, the toxic potential of atmospheric pollutants such as BD in the ambient environment is currently unclear. During this study, environmental irradiation chambers (also called smog chambers), utilizing natural sunlight, were used to create photochemical transformations of BD. The smog chamber/in vitro exposure system was designed to investigate the toxicity of chemicals before and after photochemical reactions and to investigate interactions with the urban atmosphere using representative in vitro samples. In this study, we determined the relative toxicity and inflammatory gene expression induced by coupling smog chamber atmospheres with an in vitro system to expose human respiratory epithelial cells to BD, BDs photochemical degradation products, or the equivalent ozone generated within the photochemical mixture. Exposure to the photochemically generated products of BD (primarily acrolein, acetaldehyde, formaldehyde, furan and ozone) induced significant increases in cytotoxicity, IL-8, and IL-6 gene expression compared to a synthetic mixture of primary products that was created by injecting the correct concentrations of the detected products from the irradiation experiments. Interestingly, exposure to the equivalent levels of ozone generated during the photochemical transformation of BD did not induce the same level of inflammatory cytokine release for either exposure protocol, suggesting that the effects from ozone alone do not account for the entire response in the irradiation experiments. These results indicate that BDs full photochemical product generation and interactions, rather than ozone alone, must be carefully evaluated when investigating the possible adverse health effects to BD exposures. The research presented here takes into account that photochemical transformations of hazardous air pollutants (HAPs) does generate a dynamic exposure system and therefore provides a more realistic approach to estimate the toxicity of ambient air pollutants once they are released into the atmosphere.     

Asymmetric deceleration of ClpB or Hsp104 ATPase activity unleashes protein-remodeling activity

Two members of the AAA+ superfamily, ClpB and Hsp104, collaborate with Hsp70 and Hsp40 to rescue aggregated proteins. However, the mechanisms that elicit and underlie their protein-remodeling activities remain unclear. We report that for both Hsp104 and ClpB, mixtures of ATP and ATP-gammaS unexpectedly unleash activation, disaggregation and unfolding activities independent of cochaperones. Mutations reveal how remodeling activities are elicited by impaired hydrolysis at individual nucleotide-binding domains. However, for some substrates, mixtures of ATP and ATP-gammaS abolish remodeling, whereas for others, ATP binding without hydrolysis is sufficient. Remodeling of different substrates necessitates a diverse balance of polypeptide 'holding' (which requires ATP binding but not hydrolysis) and unfolding (which requires ATP hydrolysis). We suggest that this versatility in reaction mechanism enables ClpB and Hsp104 to reactivate the entire aggregated proteome after stress and enables Hsp104 to control prion inheritance.     

Brazilian red propolis reduces orange-complex periodontopathogens growing in multispecies biofilms

This study investigated the antimicrobial effects of the ethanolic extract of Brazilian red propolis (BRP) on multispecies biofilms. A seven-day-old subgingival biofilm with 32 species was grown in a Calgary device. Biofilms were treated with BRP (1,600, 800, 400 and 200?μg ml^?1) twice a day for 1?min, starting from day 3. Chlorhexidine (0.12%) and dilution-vehicle were used as positive and negative controls, respectively. On day 7, metabolic activity and the microbial composition of the biofilms by DNA-DNA hybridization were determined. The viability data were analyzed by one-way ANOVA followed by Tukey’s post hoc, whereas the microbial composition data were transformed via BOX-COX and analyzed using Dunnett’s post hoc. BRP (1,600?μg ml^?1) decreased biofilm metabolic activity by 45%, with no significant difference from chlorhexidine-treated samples. BRP (1,600?μg ml^?1) and chlorhexidine significantly reduced levels of 14 bacterial species compared to the vehicle control. Taken together, BRP showed promising antimicrobial properties which may be useful in periodontal disease control.