Bulletin No. 12: System dynamics modelling using a stocks and flows approach

One of the key components of the first phase of the DPMP project has been to develop a quantitative dynamic model of drug use in Australia. Using a stocks and flows approach, derived from similar work undertaken in the US on cocaine prevalence by Caulkins and collaborators, the key aim of this component of the DPMP has been to examine whether methods can be applied to the Australian context using available data. If a plausible model could be developed, then the subsequent aims were to use the model to describe: 1.The prevalence of drug use in Australia over time; and 2. the effects of changes in model parameters upon the prevalence of injecting drug use and the associated social costs

Bulletin No. 6: Illicit drugs in Australia: What do we know about the role of price?

There has been an increasing awareness of the importance of using price information to understand illicit drug markets. Internationally, researchers have found relationships between illicit drug prices and other market characteristics such as the numbers of drug users, the proportion of arrestees testing positive to drugs and the number of drug-related emergency department incidents. This work aimed to assess whether the Australian heroin market shares the same basic characteristics (e.g. real prices falling over time, significant price variability) as other illicit drug markets where more price analysis has been done; and begin to explore the relationship between price and harm. It is hard to measure how much heroin is being consumed with any precision, making it extremely difficult to understand the relationship between drug use and the harmful consequences that result from use. On the other hand other market characteristics, such as price, can be better measured. If there are relationships between price (as an indirect measure of consumption) and harms, we can use price (and potentially other market data) to assess harms and policy responses

“PMA Sounds Fun”: Negotiating Drug Discourses Online

In 2007, a young woman, Annabel Catt, died after consuming a capsule sold as “ecstasy” that contained para-methoxyamphetamine. In this paper, we describe how this death was depicted in online drug-user communities and illustrate how the meanings of drug use are negotiated in online settings. News articles, public online discussions, and online fieldwork formed the data. This paper demonstrates how dominant drug discourses may be resisted by drug users, drawing on theories of health resistance and Kane Race’s concept of counter public health. Online environments may offer ways of engaging people who use drugs that acknowledge both pleasure and safety. The study’s limitations are noted

Erratum: Sequence data and association statistics from 12,940 type 2 diabetes cases and controls.

This corrects the article DOI: 10.1038/sdata.2017.179

The Type 2 Diabetes Knowledge Portal: an open access genetic resource dedicated to type 2 diabetes and related traits

Associations between human genetic variation and clinical phenotypes have become a foundation of biomedical research. Most repositories of these data seek to be disease-agnostic and therefore lack disease-focused views. The Type 2 Diabetes Knowledge Portal (T2DKP) is a public resource of genetic datasets and genomic annotations dedicated to type 2 diabetes (T2D) and related traits. Here, we seek to make the T2DKP more accessible to prospective users and more useful to existing users. First, we evaluate the T2DKP's comprehensiveness by comparing its datasets with those of other repositories. Second, we describe how researchers unfamiliar with human genetic data can begin using and correctly interpreting them via the T2DKP. Third, we describe how existing users can extend their current workflows to use the full suite of tools offered by the T2DKP. We finally discuss the lessons offered by the T2DKP toward the goal of democratizing access to complex disease genetic results

Skeletal Adaptation to Intramedullary Pressure-Induced Interstitial Fluid Flow Is Enhanced in Mice Subjected to Targeted Osteocyte Ablation

Interstitial fluid flow (IFF) is a potent regulatory signal in bone. During mechanical loading, IFF is generated through two distinct mechanisms that result in spatially distinct flow profiles: poroelastic interactions within the lacunar-canalicular system, and intramedullary pressurization. While the former generates IFF primarily within the lacunar-canalicular network, the latter generates significant flow at the endosteal surface as well as within the tissue. This gives rise to the intriguing possibility that loading-induced IFF may differentially activate osteocytes or surface-residing cells depending on the generating mechanism, and that sensation of IFF generated via intramedullary pressurization may be mediated by a non-osteocytic bone cell population. To begin to explore this possibility, we used the Dmp1-HBEGF inducible osteocyte ablation mouse model and a microfluidic system for modulating intramedullary pressure (ImP) to assess whether structural adaptation to ImP-driven IFF is altered by partial osteocyte depletion. Canalicular convective velocities during pressurization were estimated through the use of fluorescence recovery after photobleaching and computational modeling. Following osteocyte ablation, transgenic mice exhibited severe losses in bone structure and altered responses to hindlimb suspension in a compartment-specific manner. In pressure-loaded limbs, transgenic mice displayed similar or significantly enhanced structural adaptation to Imp-driven IFF, particularly in the trabecular compartment, despite up to ∼50% of trabecular lacunae being uninhabited following ablation. Interestingly, regression analysis revealed relative gains in bone structure in pressure-loaded limbs were correlated with reductions in bone structure in unpressurized control limbs, suggesting that adaptation to ImP-driven IFF was potentiated by increases in osteoclastic activity and/or reductions in osteoblastic activity incurred independently of pressure loading. Collectively, these studies indicate that structural adaptation to ImP-driven IFF can proceed unimpeded following a significant depletion in osteocytes, consistent with the potential existence of a non-osteocytic bone cell population that senses ImP-driven IFF independently and potentially parallel to osteocytic sensation of poroelasticity-derived IFF