Rate of, and risk factors for, white matter hyperintensity growth: a systematic review and meta-analysis with implications for clinical trial design

BackgroundWhite matter hyperintensities (WMHs) are a highly prevalent MRI marker of cerebral small vessel disease (SVD), which predict stroke and dementia risk, and are being increasingly used as a surrogate marker in clinical trials. However, the influence of study population selection on WMH progression rate has not been studied and the effect of individual patient factors for WMH growth are not fully understood.MethodsWe performed a systematic review and meta-analysis of the literature on progression of WMHs in longitudinal studies to determine rates of WMH growth, and how these varied according to population characteristics and cardiovascular risk factors. We used these data to calculate necessary sample sizes for clinical trials using WMH as an endpoint.ResultsWMH growth rate was highest in SVD (2.50cc/year), intermediate in unselected stroke patients (1.29cc/year) and lower in patients with non-stroke cardiovascular disease, and with cognitive impairment. Age was significantly associated with progression (correlation coefficient 0.15cc/year, 95% CI 0.02 to 0.28cc/year) as was baseline lesion volume (0.6cc/year, 95% CI 0.13 to 1.06 cc/year). Both hypertension (OR 1.72, 95% CI 1.19 to 2.46) and current smoking (OR 1.48, 95% CI 1.02 to 2.16) were associated with WMH growth. Sample sizes for a clinical trial varied greatly with patient population selection and baseline lesion volume; estimates are provided.ConclusionsWMH progression varies markedly according to the characteristics of the population being studied and this will have a major impact on sample sizes required in a clinical trial. Our sample size estimates provide data for planning clinical trials using WMH as an outcome measure.PROSPERO registration numberCRD42020191781.

Choosing source populations for conservation reintroductions: lessons from variation in thermal tolerance among populations of the imperilled redside dace

Reintroduction is an increasingly common conservation tool to recover populations of imperilled species, but success depends on the suitability of the introduced animals’ phenotype for their new habitat. For fishes, thermal tolerance may be a key trait in urbanized habitats. We compared thermal tolerance (CTmax) among three lineages (western, central, eastern) of imperilled redside dace Clinostomus elongatus. CTmax of eastern adults was 3-4°C lower than the other lineages, but adults of each lineage had similar thermal acclimation responses. In contrast, the acclimation response of juveniles differed by ~80% between the central and western lineages. Using this data, we predicted how each lineage would fare in a hypothetical reintroduction to relatively warm urbanized habitats. Due to the differences in juvenile acclimation responses, predicted thermal safety margins for the central lineage were double those predicted for the western lineage. Overall, we suggest that CTmax is a useful trait to incorporate into the source population selection process. However, there is an urgent need for the establishment of captive experimental research populations of imperilled species to address remaining uncertainties.

Microbial population selection in integrated fixed-film sequencing batch reactors operated with different lengths of oxic and anoxic conditions

BNR granules rich in amyloid adhesins and denitrifying bacteria were formed in the SBRs that were operated with extended anoxic conditions.

The evaluation of productive traits of pigs with application methods of population selection and molecular genetic markers

The comprehensive evaluation of the productive traits of the initial genotypes of pigs in the creation of breeding herds using population selection methods has been carried out. Based on the results of evaluating the growth and development of breeding animals using the methods of index selection and DNA testing for the genes markers RYR1, ESR, IGF-2, MUC4 the genealogical structure of breeding herds has been formed on the basis of new stud lines of Belarusian stud type of pigs of Yorkshire breed. It has been found that sows of new lines had high reproduction rates: prolifi cacy was 11,6 piglets, milk capacity was 59,1 kg, number of piglets at weaning was 11,2 heads, and litter weight at weaning was 103,6 kg. The breeding herd of two new stud lines is represented by boars of the line Drug 6805 and Dobry 2313. The average productivity of boars-line continuers was: the age of reaching a live weight of 100 kg to 160 days, the average daily gain from birth to reaching the live weight of 100 kg was 636 g. At the age of 12 months, the live weight and body length of replacement boars were 268 kg and 175 cm, the thickness of the fat was 8,9 mm, the height of the longest back muscle was 51,5 mm, the content of lean meat in the body was 62,6 %, which corresponds to the class “elite”. Boars have been separated into reproductive traits. Improvement of lines is carried out through the continuators of related groups. Analysis of genetic studies of animals of new stud lines has shown that they have a high frequency of occurrence of desirable alleles by genes: RYR1 (stress-resistant animals) – 1,0; IGF-2 (fattening and meat traits) – 0,783; ESR (reproductive traits) – 0,608; MUC4 – (resistance to escherichiosis) – 0,786.