Biomedical subjects

Ming-Huei Chen

Publications and source records attributed to Ming-Huei Chen.

5 recordsLinked to original sources

PubMed2025

Genetic study of von Willebrand factor antigen levels ≤ 50 IU/dL identifies variants associated with increased risk of von Willebrand disease and bleeding.

BACKGROUND: von Willebrand disease (VWD) is a common inherited bleeding disorder caused by low levels or activity of circulating von Willebrand factor (VWF). Genetic susceptibility to VWF antigen (VWF:Ag) below normal (≤ 50 IU/dL) in the general population is underexplored. OBJECTIVES: To identify genetic variants influencing VWF:Ag levels ≤ 50 IU/dL. METHODS: We performed a genome-wide association study in 926 cases with VWF:Ag levels ≤ 50 IU/dL and 12 846 controls from 7 studies from the Trans-Omics for Precision Medicine program. We then examined whether significant genome-wide findings were also associated with clinical diagnosis of VWD in 5 biobanks with 708 VWD cases and 1 286 069 controls, and with 6 bleeding and thrombotic disorders in FinnGen. RESULTS: Variants at 2 loci were associated (P < 5 × 10-9) with VWF:Ag levels ≤ 50 IU/dL: ABO and VWF. The VWF index variant, p.Tyr1584Cys, is a rare (0.22%) missense variant with odds ratio (OR) of 78.58, while the ABO index variant is a common intronic variant with a smaller effect (OR = 2.52). Notably, both VWF (OR = 7.16) and ABO (OR = 1.57) variants were also associated (P < .025) with diagnosed VWD. Among p.Tyr1584Cys heterozygotes, the penetrance of VWF:Ag levels ≤ 50 IU/dL was 24.2% and the penetrance of diagnosed VWD was 0.3%. p.Tyr1584Cys was associated (P < .0042) with increased odds of heavy menstrual bleeding (OR = 1.27), iron deficiency anemia (OR = 1.55), and intrapartum hemorrhage (OR = 2.20), but decreased odds of deep vein thrombosis (OR = 0.54). CONCLUSIONS: Although there are currently conflicting interpretations of pathogenicity p.Tyr1584Cys, our results suggest that it is a low penetrance pathogenic variant that contributes to VWF:Ag levels ≤ 50 IU/dL, bleeding, and VWD.

Humans↗

PubMed2006

A cost-effective line-based light-balancing technique using adaptive processing.

The camera imaging system has been widely used; however, the displaying image appears to have an unequal light distribution. This paper presents novel light-balancing techniques to compensate uneven illumination based on adaptive signal processing. For text image processing, first, we estimate the background level and then process each pixel with nonuniform gain. This algorithm can balance the light distribution while keeping a high contrast in the image. For graph image processing, the adaptive section control using piecewise nonlinear gain is proposed to equalize the histogram. Simulations show that the performance of light balance is better than the other methods. Moreover, we employ line-based processing to efficiently reduce the memory requirement and the computational cost to make it applicable in real-time systems.

Algorithms↗

PubMed2005

Identification of polymorphisms explaining a linkage signal: application to the GAW14 simulated data.

We applied three approaches for the identification of polymorphisms explaining the linkage evidence to the Genetic Analysis Workshop 14 simulated data: 1) the genotype-IBD sharing test (GIST); 2) an approach suggested by Horikawa and colleagues; and 3) the homozygote sharing test (HST). These tests were compared with a family-based association test. Two linked regions with highest nonparametric linkage scores were selected to apply these methods. In the first region, Horikawa's method identified the most SNPs within the region containing the disease susceptibility locus, while HST performed best in the second region. However, Horikawa's method also had the most type I errors. These methods show potential as additional tools to complement family-based association tests for the identification of disease susceptibility variants.

Chromosomes, Human, Pair 1↗

PubMed2005

Heritability and a genome-wide linkage scan for arterial stiffness, wave reflection, and mean arterial pressure: the Framingham Heart Study.

BACKGROUND: Arterial stiffness and mean arterial pressure variably contribute to systolic hypertension and increased cardiovascular risk. However, few prior community-based studies have evaluated the genetics of arterial stiffness and separate mean and pulsatile components of blood pressure. METHODS AND RESULTS: Using arterial tonometry, we evaluated heritability and linkage of forward and reflected wave amplitude, mean arterial pressure, and carotid-femoral pulse wave velocity (CFPWV) in 1480 participants representing 817 pedigrees in the Framingham Study offspring cohort. In 204 families with tonometry data, a genome-wide scan was performed with microsatellite markers that covered the genome at 10-cM intervals. Heritability estimates were moderate for reflected wave amplitude (h2=0.48), forward wave amplitude (h2=0.21), CFPWV (h2=0.40), and mean arterial pressure (h2=0.33). Variance components linkage analysis identified 2 regions of linkage for reflected wave amplitude: chromosome 4 at 181 cM (logarithm of odds [LOD]=4.93, permuted P=0.002) and chromosome 8 at 33 cM (LOD=3.27, permuted P=0.058). There was 1 region of linkage for forward wave amplitude on chromosome 7 at 174 cM (LOD=2.88, permuted P=0.017). There were several regions of suggestive linkage for CFPWV: chromosome 2 at 94 cM (LOD=2.46), chromosome 7 at 29 cM (LOD=2.50), chromosome 13 at 108 cm (LOD=2.10), and chromosome 15 at 108 cM (LOD=2.48). There was 1 region of suggestive linkage for mean arterial pressure on chromosome 1 at 192 cM (LOD=2.18). CONCLUSIONS: Arterial stiffness measures and mean and pulsatile components of blood pressure are heritable and appear to have genetic determinants that may be linked to separate genetic loci in humans.

Aged↗

PubMed2002

Limited feasibility of routinely analyzing fetal cells from maternal blood by using magnetic activated cell sorting and polymerase chain reaction for prenatal diagnosis.

BACKGROUND: To assess the feasibility of analyzing fetal cells from maternal circulation by using magnetic activated cell sorting (MACS) and polymerase chain reaction (PCR) for prenatal diagnosis. METHODS: Thirty-one high-risk (either advanced maternal age or abnormal serum Down screening) pregnant women (14-22 weeks) were enrolled. Twenty ml of venous blood from each woman after amniocentesis were pretreated with density gradient centrifugation and sorted by MACS with monoclonal antibodies: anti-CD71 (n = 26) or anti-GPA (n = 5). Nested PCR with Y-specific probes--Y1.5-Y1.8 (n = 10) and Amelogenin (n = 21) were then applied to the sorted nucleated red blood cells (NRBCs) for fetal sex determination. These results were compared with cytogenetic data. To assess the sensitivity of PCR, different proportions of known male and female cultured amniocytes were mixed and amplified for gender identification. RESULTS: Karyotypes were normal in all fetuses (18 females and 13 males). The proportions of NRBCs (in total cells) sorted by MACS--anti-GPA or anti-CD71 were 50% (2000 +/- 1500) and 85% (350 +/- 280), respectively. Accuracies of sex determination by PCR-Amelogenin or Y1.5-Y1.8 were 76.2% (16/21) and 50% (5/10), respectively. Three cases resulted in PCR failure. Assay of nested PCR inferred that after cell sorting, existence of at least 20% of male fetal cells mixed in maternal blood circulation was required for prenatal diagnosis under current methodology. CONCLUSIONS: We confirmed the existence of fetal NRBCs in maternal blood during pregnancy. The low accuracy of sex determination (76.2%) may be attributed to contamination of either maternal NRBCs or non-NRBCs. No conclusive data, however, so far demonstrates the ideal marker to identify the origin of NRBCs. Without specific fetal cell marker and more sophisticated fetal cell analysis methodologies, in our experience, the feasibility of routinely analyzing fetal cells from maternal blood for prenatal diagnosis is limited.

Erythrocytes↗