Modelling the growth of popliteal artery aneurysms

Background

Popliteal artery aneurysms (PAAs) comprise up to 85 per cent of all peripheral aneurysms. Few longitudinal studies track their progression. This study aimed to track the growth of asymptomatic PAAs in a hospital-based ultrasound service, and compare models of aneurysm growth.

Methods

This retrospective single-centre cohort study included patients who had a PAA on arterial duplex ultrasound imaging of the lower limbs between 1 January 2011 and 1 January 2016. Progression of PAA size and progression to event or intervention were the primary outcome measures.

Results

Some 282 images were analysed: 47 limbs with PAA were included in a cohort of 32 patients (15 had bilateral PAAs). Twenty patients also had an abdominal aortic aneurysm (AAA). Linear multilevel modelling estimated that PAA growth was 2·4 (95 per cent c.i. 1·6 to 3·7) mm a year. Growth was estimated at 0·8 (0·1 to 1·5) mm per year in patients without an AAA and 3·5 (2·9 to 4·2) mm per year in those with a known AAA (previous open repair, previous endovascular aneurysm repair or AAA under surveillance) (P < 0·001).

Conclusion

Growth rates of PAA were heterogeneous but were optimally predicted by multilevel modelling. Patients with an existing AAA may have faster PAA progression than those without.

Characterizing the PAHs in surface waters and snow in the Athabasca region: Implications for identifying hydrological pathways of atmospheric deposition

The composition of polycyclic aromatic hydrocarbons present in snow and surface waters in the Athabasca Oil Sands Region (AOSR) was characterized in order to identify major contributors to the organics detected in rivers and lakes in the region. PAH concentrations, measured by three monitoring programs in 2011, were used to compare the PAH compositions of snow and surface waters across the AOSR. The 2011 dataset includes total (dissolved+particulate) concentrations of thirty-four parent and alkylated PAH compounds in 105 snow, 272 river, and 3 lake samples. The concentration of PAHs in rivers varies seasonally, with the highest values observed in July. The timing of increases in PAH concentrations in rivers coincides with the high river discharge during the spring freshet, indicating that this major hydrological event may play an important role in delivering PAHs to rivers. However, the composition of PAHs present in rivers during this period differs from the composition of PAHs present in snow, suggesting that direct runoff and release of PAHs accumulated on snow may not be the major source of PAHs to the Athabasca River and its tributaries. Instead, snowmelt may contribute indirectly to increases in PAHs due to hydrological processes such as erosion of stream channels, remobilization of PAH-containing sediments, increased catchment runoff, and snowmelt-induced groundwater inputs during this dynamic hydrologic period. Better understanding of transformations of PAH profiles during transport along surface and subsurface flow paths in wetland-dominated boreal catchments would improve identification of potential sources and pathways in the region. The compositional differences highlight the challenges in identifying the origins of PAHs in a region with multiple potential natural and anthropogenic sources particularly when the potential transport pathways include air, soil and water.

Observation of the Leggett-Rice effect in a unitary Fermi gas

We observe that the diffusive spin current in a strongly interacting degenerate Fermi gas of (40)K precesses about the local magnetization. As predicted by Leggett and Rice, precession is observed both in the Ramsey phase of a spin-echo sequence, and in the nonlinearity of the magnetization decay. At unitarity, we measure a Leggett-Rice parameter γ=1.08(9) and a bare transverse spin diffusivity D(0)(⊥)=2.3(4)ℏ/m for a normal-state gas initialized with full polarization and at one-fifth of the Fermi temperature, where m is the atomic mass. One might expect γ=0 at unitarity, where two-body scattering is purely dissipative. We observe γ→0 as temperature is increased towards the Fermi temperature, consistent with calculations that show the degenerate Fermi sea restores a nonzero γ. Tuning the scattering length a, we find that a sign change in γ occurs in the range 0<(k(F)a)(-1)≲1.3, where k(F) is the Fermi momentum. We discuss how γ reveals the effective interaction strength of the gas, such that the sign change in γ indicates a switching of branch between a repulsive and an attractive Fermi gas.

Evaluation of a psychoeducation programme for parents of children and adolescents with ADHD: immediate and long-term effects using a blind randomized controlled trial

Recent guidelines for the diagnosis and treatment of attention deficit hyperactivity disorder (ADHD) have claimed the possible benefits of psychoeducational techniques in the comprehensive management of ADHD. To evaluate the efficacy of a psychoeducation programme for parents of children and adolescents with ADHD in a clinical setting using a blind randomized trial. 81 children/adolescents with ADHD were randomly assigned for their families to receive either a well-structured psychoeducation programme (intervention group, n = 44), or a parent counselling and support intervention (control group, n = 37). Measures of child ADHD symptoms, psychopathology, quality of life and family stress were taken before and after intervention and after a year follow-up. Parents and evaluators were unaware of the condition received. Compared to the support control group, the psychoeducation group showed ADHD Index and cognitive/inattention levels significantly reduced after the intervention ended (Mann-Whitney U = 3.34; p = 0.001; Mann-Whitney U = 3.47; p = 0.001). An improvement in the pro-social domain was also observed after 1 year follow-up (Mann-Whitney U = -2.37; p = 0.018), and clinical global impression found a statistically significant effect for severity over the time. Differences were initially found for the impact of the disorder in the family in different domains, including emotional and social functioning; these differences were no longer significant after alpha correction. No significant differences in quality of life or family stress were found in comparison with the control group. This psychoeducation programme is a valuable treatment for parents/carers of children/adolescents with ADHD, which needs to be considered when evaluating different non-pharmacological treatment options. Psychoeducation and other kind of non-pharmacological approaches need to be regarded not as a substitute, but as a complementary treatment to medications; these approaches might help other very crucial aspects of ADHD including social and familiar outcomes.

Short communication. The role of animal-sourced insulin in the treatment of type 1 diabetes and its availability

As a result of a number of factors, the treatment of insulin-dependent diabetes has moved away from using insulin of beef or pork origin to using recombinant (biosynthetic) insulin preparations. However, some people with type 1 diabetes can manage their diabetes better using animal-sourced insulin. Despite dwindling options and decreased production, animal-sourced insulin (and pork insulin in particular) is still available on the Canadian market. This communication describes the actions taken by Health Canada with respect to the availability of animal insulin.