Genetic evidence supports recolonisation by Mya arenaria of western Europe from North America

The softshell clam Mya arenaria (L.) is currently widespread on the east and west coasts of North America. This bivalve also occurs on western European shores, where the post-Pleistocene origin of the species, whether introduced or relict, has been debated. We collected 320 M. arenaria from 8 locations in Europe and North America. Clams (n = 84) from 7 of the locations were examined for mitochondrial DNA variation by sequencing a section of the cytochrome oxidase 1 (COX1) gene. These were analysed together with 212 sequences, sourced from GenBank, from the same gene from 12 additional locations, chiefly from eastern North America but also 1 site each from western North America and from western Europe. Ten microsatellite loci were also investigated in all 320 clams. Nuclear markers showed reduced levels of variation in certain European samples. The same common COX1 haplotypes and microsatellite alleles were present throughout the range of M. arenaria, although significant differences were identified in haplotypic and allelic composition between many samples, particularly those from the 2 continents (Europe and North America). These findings support the hypothesis of post-Pleistocene colonisation of European shores from eastern North America (and the recorded human transfer of clams from the east to the west coast of North America in the 19th century).

Polypharmacy and inappropriate medication use in patients with dementia: an underresearched problem

Multimorbidity and polypharmacy are increasingly prevalent across healthcare systems and settings as global demographic trends shift towards increased proportions of older people in populations. Numerous studies have demonstrated an association between polypharmacy and potentially inappropriate prescribing (PIP), and have reported high prevalence of PIP across settings of care in Europe and North America and, as a consequence, increased risk of adverse drug reactions, healthcare utilisation, morbidity and mortality. These studies have not focused specifically on people with dementia, despite the high risk of adverse drug reactions and PIP in this patient cohort. This narrative review considers the evidence currently available in the area, including studies examining prevalence of PIP in older people with dementia, how appropriateness of prescribing is assessed, the medications most commonly implicated, the clinical consequences, and research priorities to optimise prescribing for this vulnerable patient group. Although there has been considerable research effort to develop criteria to assess medication appropriateness in older people in recent years, the majority of tools do not focus on people with dementia. Of the limited number of tools available, most focus on the advanced stages of dementia in which life-expectancy is limited. The development of tools to assess medication appropriateness in people with mild-to-moderate dementia or across the full spectrum of disease severity represents an important gap in the research literature and is beginning to attract research interest, with recent studies considering the medication regimen as a whole, or misprescribing, overprescribing or underprescribing of certain medications/medication classes including anticholinergics, psychotropics, antibiotics and analgesics. Further work is required in development and validation of criteria to assess prescribing appropriateness in this vulnerable patient population, to determine prevalence of PIP in large cohorts of people with the full spectrum of dementia variants and severities and to examine the impact of PIP on health outcomes.