11 research outputs found
A Meta-Analysis and Genome-Wide Association Study of Platelet Count and Mean Platelet Volume in African Americans
Several genetic variants associated with platelet count and mean platelet volume
(MPV) were recently reported in people of European ancestry. In this
meta-analysis of 7 genome-wide association studies (GWAS) enrolling African
Americans, our aim was to identify novel genetic variants associated with
platelet count and MPV. For all cohorts, GWAS analysis was performed using
additive models after adjusting for age, sex, and population stratification. For
both platelet phenotypes, meta-analyses were conducted using inverse-variance
weighted fixed-effect models. Platelet aggregation assays in whole blood were
performed in the participants of the GeneSTAR cohort. Genetic variants in ten
independent regions were associated with platelet count
(N = 16,388) with p<5×10−8 of
which 5 have not been associated with platelet count in previous GWAS. The novel
genetic variants associated with platelet count were in the following regions
(the most significant SNP, closest gene, and p-value): 6p22 (rs12526480,
LRRC16A, p = 9.1×10−9), 7q11
(rs13236689, CD36, p = 2.8×10−9),
10q21 (rs7896518, JMJD1C,
p = 2.3×10−12), 11q13 (rs477895,
BAD, p = 4.9×10−8), and 20q13
(rs151361, SLMO2, p = 9.4×10−9).
Three of these loci (10q21, 11q13, and 20q13) were replicated in European
Americans (N = 14,909) and one (11q13) in Hispanic
Americans (N = 3,462). For MPV
(N = 4,531), genetic variants in 3 regions were significant
at p<5×10−8, two of which were also associated with
platelet count. Previously reported regions that were also significant in this
study were 6p21, 6q23, 7q22, 12q24, and 19p13 for platelet count and 7q22,
17q11, and 19p13 for MPV. The most significant SNP in 1 region was also
associated with ADP-induced maximal platelet aggregation in whole blood (12q24).
Thus through a meta-analysis of GWAS enrolling African Americans, we have
identified 5 novel regions associated with platelet count of which 3 were
replicated in other ethnic groups. In addition, we also found one region
associated with platelet aggregation that may play a potential role in
atherothrombosis
Artifact Rejection Methodology Enables Continuous, Noninvasive Measurement of Gastric Myoelectric Activity in Ambulatory Subjects
Abstract The increasing prevalence of functional and motility gastrointestinal (GI) disorders is at odds with bottlenecks in their diagnosis, treatment, and follow-up. Lack of noninvasive approaches means that only specialized centers can perform objective assessment procedures. Abnormal GI muscular activity, which is coordinated by electrical slow-waves, may play a key role in symptoms. As such, the electrogastrogram (EGG), a noninvasive means to continuously monitor gastric electrical activity, can be used to inform diagnoses over broader populations. However, it is seldom used due to technical issues: inconsistent results from single-channel measurements and signal artifacts that make interpretation difficult and limit prolonged monitoring. Here, we overcome these limitations with a wearable multi-channel system and artifact removal signal processing methods. Our approach yields an increase of 0.56 in the mean correlation coefficient between EGG and the clinical “gold standard”, gastric manometry, across 11 subjects (p < 0.001). We also demonstrate this system’s usage for ambulatory monitoring, which reveals myoelectric dynamics in response to meals akin to gastric emptying patterns and circadian-related oscillations. Our approach is noninvasive, easy to administer, and has promise to widen the scope of populations with GI disorders for which clinicians can screen patients, diagnose disorders, and refine treatments objectively