Predictive Association of Smoking with Depressive Symptoms: a Longitudinal Study of Adolescent Twins

Prevention Science - Longitudinal, genetically informative studies of the association between cigarette smoking and depressive symptoms among adolescents are limited. We examined the longitudinal...     

The effectiveness of body weight-supported gait training and floor walking in patients with chronic stroke

OBJECTIVE: To compare body weight-supported exercise on a gait trainer with walking exercise overground. DESIGN: Randomized controlled trial. SETTING: Rehabilitation hospital. PARTICIPANTS: Forty-five ambulatory patients with chronic stroke. INTERVENTIONS: Patients were randomized to 3 groups: (1) gait trainer exercise with functional electric stimulation (GTstim), (2) gait trainer exercise without stimulation (GT), and (3) walking overground (WALK). All patients practiced gait for 15 sessions during 3 weeks (each session, 20 min), and they received additional physiotherapy 55 minutes daily. MAIN OUTCOME MEASURES: Ten-meter walk test (10MWT), six-minute walk test (6MWT), lower-limb spasticity and muscle force, postural sway tests, Modified Motor Assessment Scale (MMAS), and FIM instrument scores were recorded before, during, and after the rehabilitation and at 6 months follow-up. RESULTS: The mean walking distance using the gait trainer was 6900+/-1200 m in the GTstim group and 6500+/-1700 m in GT group. In the WALK group, the distance was 4800+/-2800 m, which was less than the walking distance obtained in the GTstim group (P=.027). The body-weight support was individually reduced from 30% to 9% of the body weight over the course of the program. In the pooled 45 patients, the 10MWT (P<.001), 6MWT (P<.001), MMAS (P<.001), dynamic balance test time (P<.001), and test trip (P=.005) scores improved; however, no differences were found between the groups. CONCLUSIONS: Both the body weight-supported training and walking exercise training programs resulted in faster gait after the intensive rehabilitation program. Patients' motor performance remained improved at the follow-up.     

ERP denoising in multichannel EEG data using contrasts between signal and noise subspaces

In this paper, a new method intended for ERP denoising in multichannel EEG data is discussed. The denoising is done by separating ERP/noise subspaces in multidimensional EEG data by a linear transformation and the following dimension reduction by ignoring noise components during inverse transformation. The separation matrix is found based on the assumption that ERP sources are deterministic for all repetitions of the same type of stimulus within the experiment, while the other noise sources do not obey the determinancy property. A detailed derivation of the technique is given together with the analysis of the results of its application to a real high-density EEG data set. The interpretation of the results and the performance of the proposed method under conditions, when the basic assumptions are violated – e.g. the problem is underdetermined – are also discussed.Moreover, we study how the factors of the number of channels and trials used by the method influence the effectiveness of ERP/noise subspaces separation. In addition, we explore also the impact of different data resampling strategies on the performance of the considered algorithm. The results can help in determining the optimal parameters of the equipment/methods used to elicit and reliably estimate ERPs.     

Self-rated Health and Social Capital Among Aging People Across the Urban–Rural Dimension

Background

Previous studies have found self-rated health to be associated with social capital. However, there is lack of studies examining social capital among aging people and its impact on self-rated health in the urban–rural context.

Purpose

The purpose of this study was to investigate associations between self-rated health and indicators of social capital (trust, various social contacts, social participation, and access to help) among aging people living in urban and rural areas in Finland.

Method

A postal survey was conducted in 2002 among men and women born in 1926–1930, 1936–1940, or 1946–1950 and dwelling in 14 municipalities in the Päijät-Häme hospital district in Finland. A total of 2,815 participants represented 66% of the original stratified (by age, gender, and municipality) sample. Logistic regression analyses were used to examine the associations.

Results

Active social participation and easy access to help from others were associated with good self-rated health, especially in the urban and sparsely populated rural areas. Trust was a particularly important correlate of subjective health in the urban area, though its significance diminished after adjusting to all background variables. No overall disparities in self-rated health between the areas emerged. Social participation and access to help as indicators of social capital seem to be important resources when aging men and women assess their subjective health.

Conclusion

Increasing efforts to encourage social participation and facilitate access to help from other persons should be included among the key priorities in community health promotion.     

Geographical structure and differential natural selection among North European populations

Population structure can provide novel insight into the human past, and recognizing and correcting for such stratification is a practical concern in gene mapping by many association methodologies. We investigate these patterns, primarily through principal component (PC) analysis of whole genome SNP polymorphism, in 2099 individuals from populations of Northern European origin (Ireland, United Kingdom, Netherlands, Denmark, Sweden, Finland, Australia, and HapMap European-American). The major trends (PC1 and PC2) demonstrate an ability to detect geographic substructure, even over a small area like the British Isles, and this information can then be applied to finely dissect the ancestry of the European-Australian and European-American samples. They simultaneously point to the importance of considering population stratification in what might be considered a small homogeneous region. There is evidence from F_ST-based analysis of genic and nongenic SNPs that differential positive selection has operated across these populations despite their short divergence time and relatively similar geographic and environmental range. The pressure appears to have been focused on genes involved in immunity, perhaps reflecting response to infectious disease epidemic. Such an event may explain a striking selective sweep centered on the rs2508049-G allele, close to the HLA-G gene on chromosome 6. Evidence of the sweep extends over a 8-Mb/3.5-cM region. Overall, the results illustrate the power of dense genotype and sample data to explore regional population variation, the events that have crafted it, and their implications in both explaining disease prevalence and mapping these genes by association.Patterns of genetic variation within and between human populations have long provided novel insights into the origin and history of different groups. The advent of whole genome association (WGA) mapping has also highlighted the practical importance of identifying and understanding these patterns. A mismatch in the ancestry of individuals in a simple case/control association paradigm can lead to false positives and/or reduced power to detect associations.Studies of population-level whole genome (WG) polymorphism were initially restricted to the International HapMap populations (Yoruban, Japanese, Chinese, and European-Americans) but provided valuable information on intercontinental variation across the human genome, including structural variation, recombination, and selection (International HapMap Consortium 2005, 2007). The whole genome approach has now begun to be applied to more nuanced intracontinental variation within Europe. First generation studies using European-Americans or small numbers of in situ Europeans (but with relatively few markers) quickly identified a clear North–South split in the continent''s population and hinted at further structure (Seldin et al. 2006; Bauchet et al. 2007; Price et al. 2008; Seldin and Price 2008; Tian et al. 2008). Analysis of WG variation in larger numbers of individuals sampled in situ from multiple European populations has recently extended these findings. Using principal component analysis (PCA) of up to ≈300,000 SNPs, they have shown a remarkable correlation of an individual''s position in genetic space to their geographic origin (Heath et al. 2008; Lao et al. 2008; Novembre et al. 2008).We continue this progression by exploring subcontinental WG (300K) variation in 2099 individuals from six Northern European populations (Ireland, United Kingdom, Netherlands, Sweden, Denmark, and Finland), as well as two descendent New World populations (European-Australians and the European-American HapMap sample). The data demonstrate and confirm an ability to dissect regional to subregional geographic structure and also point to the discernable impact of differential natural selection on the recently diverged Northern European populations. Both of these observations have important present-day consequences in explaining disease incidence and in mapping complex traits through association methods.     

Compensation by reduced L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor responses in a mouse model with reduced gamma-aminobutyric acid type A receptor-mediated synaptic inhibition

L-alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor antagonists increase the threshold for electroshock-induced convulsions. Here, we show that a transgenic mouse line overexpressing cerebellum-restricted gamma-aminobutyric acid type A (GABA(A)) receptor alpha6 subunit in the hippocampal CA1 pyramidal cells (Thy1alpha6 mouse line) exhibits about a 20% increase in the electroshock current intensity inducing tonic hindlimb extension convulsion in 50% of the mice compared with that of their wild-type controls. AMPA receptor-mediated miniature excitatory postsynaptic currents (mEPSCs) in patch clamp recordings of CA1 pyramidal neurons in hippocampal slices had decreased amplitudes (8.4 +/- 2.2 pA) in the transgenics compared with the wild types (10.3 +/- 2.5 pA) but showed no change in current decay or frequency. Our results suggest that decreased AMPA-mediated neurotransmission might explain the increased threshold for electroconvulsions and warrant further studies on the regulation between various components of inhibition and excitation in neurons.     

The prevalence of alexithymia and its relationship with Youth Self-Report problem scales among Finnish adolescents

This study investigated the relationship between alexithymia, depressive symptoms, and Youth Self-Report (YSR) self-image profiles among 13 to 18-year-old adolescents (n = 7087) attending school in Kuopio, Finland. The final sample consisted of 3936 adolescents (1801 boys, 2135 girls) who completed structured self-rating questionnaires (Toronto Alexithymia Scale [TAS] 20, Beck Depression Inventory [BDI], and YSR) during class periods at school. The overall prevalence of alexithymia was 7.3%. However, girls in all age groups were more frequently alexithymic than boys. Regardless of sex, alexithymic youths reported more depressive symptoms as well as internalizing and externalizing problems than the others. A YSR total score of more than 70 was recorded among 33.4% of alexithymic compared with 3.7% of nonalexithymic adolescents. The TAS-20 correlated significantly with the BDI score, YSR total score, and with internalizing problems. This study revealed alexithymia among adolescents to be associated with various complications such as depressive symptoms, high scores in YSR problem scales, and difficulties in social relationships. Our findings indicate that these adolescents are at high risk of mental disorders and require treatment interventions.     

Quantitative real-time RT-PCR assay for PCA3

Objectives:To develop a quantitative, internally standardized real-time RT-PCR assay for prostate cancer antigen 3 (PCA3), a non-translated gene found to be prostate-specific and highly overexpressed in cancer, and examine the role of PCA3 in peripheral blood with a small sample cohort.Design and methods:The RT-PCR assay for PCA3 is based on target-specific lanthanide probes. Peripheral blood from 91 prostatic cancer/disorder patients and healthy controls was assayed for PCA3 and prostate-specific antigen (PSA) expression.Results:The dynamic range of the assay reaches over eight orders of magnitude and the limit of quantification is 800 copies per milliliter blood. Peripheral blood from 2/9 patients with metastasized cancers were PCA3 positive, whereas all the other samples were negative. Eight samples were PSA positive.Conclusions:The degree of PCA3 positivity in circulating cells from prostate cancer patients is low compared to that of PSA. In contrast to some previous reports, we found no PCA3 expression in healthy individuals.