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156 result(s) for "Ta, Thanh Van"
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Feasibility of combining short tandem repeats (STRs) haplotyping with preimplantation genetic diagnosis (PGD) in screening for beta thalassemia
β-thalassemia is an autosomal recessive disease with the reduction or absence in the production of β-globin chain in the hemoglobin, which is caused by mutations in the Hemoglobin subunit beta ( HBB ) gene. In Vietnam, the number of β-thalassemia carriers range from 1.5 to 25.0%, depending on ethnic and geographical areas, which is much higher than WHO’s data worldwide (1.5%). Hence, preimplantation genetic diagnosis (PGD) plays a crucial role in reducing the rate of β-thalassemia affected patients/carriers. In this research, we report the feasibility and reliability of conducting PGD in combination with the use of short tandem repeat (STR) markers in facilitating the birth of healthy children. Six STRs, which were reported to closely linked with the HBB gene, were used on 15 couples of β-thalassemia carriers. With 231 embryos, 168 blastocysts were formed (formation rate of 72.73%), and 88 were biopsied and examined with STRs haplotyping and pedigree analysis. Thus, the results were verified by Sanger sequencing, as a definitive diagnosis. Consequently, 11 over 15 couples have achieved pregnancy of healthy or at least asymptomatic offspring. Only three couples failed to detect any signs of pregnancy such as increased Human Chorionic Gonadotropin (HCG) level, foetal sac, or heart; and one couple has not reached embryo transfer as they were proposed to continue with HLA-matching to screen for a potential umbilical cord blood donor sibling. Thus, these results have indicated that the combination of PGD with STRs analysis confirmed by Sanger sequencing has demonstrated to be a well-grounded and practical clinical strategy to improve the detection of β-thalassemia in the pregnancies of couples at-risk before embryo transfer, thus reducing β-thalassemia rate in the population.
Breast Cancer Survival Defined by Biological Receptor and Menopausal Status in Vietnamese Women
Little is known about breast cancer in Vietnamese women. Previous studies have reported the frequencies of prognostic factors of breast cancer in this population. The aim of this study was to examine the prognostic factors associated with the survival rates of patients with breast cancer treated at the National Cancer Hospital, Hanoi, Vietnam. We recruited 248 women with operable breast cancer treated with surgery and adjuvant therapy. Tumor tissue samples were stained by many immunohistochemical approaches and analyzed for estrogen receptor, progesterone receptor, and HER2 gene amplification status. A Cox model was used to determine the relationship between survival and the prognostic factors. The disease-free survival rate, overall survival rate, and cancer-specific survival rate were 75.8%, 80.6%, and 86.4%, respectively, at 5 years and 62.3%, 68.1%, and 78.9%, respectively, at 10 years. The lung was the most common metastatic site. Women with factors associated with a poor prognosis (eg, advanced clinical stage, high tumor grade, progesterone receptor [PR] negativity, HER2 amplification) had significantly lower survival rates. Patients with PR-negative breast cancer had significantly worse survival rates compared to those who were PR positive, according to multivariate analysis (hazard ratio = 1.77, 95% confidence interval: 1.01-3.11, P = .045); however, there was only a statistically significant difference in postmenopausal patients. The PR was a prognostic factor in postmenopausal women with breast cancer, but not in premenopausal women.
AID mutant analyses indicate requirement for class-switch-specific cofactors
Activation-induced cytidine deaminase (AID) is the essential and sole B cell–specific factor required for class-switch recombination (CSR) and somatic hypermutation (SHM). However, it is not known how AID differentially regulates these two independent events. Involvement of several cofactors interacting with AID has been indicated by scattered distribution of loss-of-function point mutations and evolutionary conservation of the entire 198-amino-acid protein. Here, we report that human AID mutant proteins with insertions, replacements or truncations in the C-terminal region retained strong SHM activity but almost completely lost CSR activity. These results indicate that AID requires interaction with a cofactor(s) specific to CSR.
An Improved All-Digital Background Calibration Technique for Channel Mismatches in High Speed Time-Interleaved Analog-to-Digital Converters
The time-interleaved analog-to-digital converters (TIADCs), performance is seriously affected by channel mismatches, especially for the applications in the next-generation communication systems. This work presents an improved all-digital background calibration technique for TIADCs by combining the Hadamard transform for calibrating gain and timing mismatches and averaging for offset mismatch cancellation. The numerical simulation results show that the proposed calibration technique completely suppresses the spurious images due to the channel mismatches at the output spectrum, which increases the spurious-free dynamic range (SFDR) and signal-to-noise and distortion ratio (SNDR) by 74 dB and 43.7 dB, respectively. Furthermore, the hardware co-simulation on the field programmable gate array (FPGA) platform is performed to confirm the effectiveness of the proposed calibration technique. The simulation and experimental results clarify the improvement of the proposed calibration technique in the TIADC’s performance.
BRCA1/2 Mutations in Vietnamese Patients with Hereditary Breast and Ovarian Cancer Syndrome
(1) Background: Individuals with BRCA1/2 gene mutations are at increased risk of breast and ovarian cancer. The prevalence of BRCA1/2 mutations varies by race and ethnicity, and the prevalence and the risks associated with most BRCA1/2 mutations has not been unknown in the Vietnamese population. We herein screen the entire BRCA1 and BRCA2 genes for breast and ovarian cancer patients with a family history of breast cancer and ovarian cancer, thereby, suggesting a risk score associated with carrier status and history for aiding personalized treatment; (2) Methods: Between December 2017 and December 2019, Vietnamese patients who had a pathological diagnosis of breast and epithelial ovarian cancer were followed up, prospectively, after treatment from two large institutions in Vietnam. Blood samples from 33 Vietnamese patients with hereditary breast and ovarian cancers (HBOC) syndrome were collected and analyzed using Next Generation Sequencing; (3) Results: Eleven types of mutations in both BRCA1 (in nine patients) and BRCA2 (in three patients) were detected, two of which (BRCA1:p.Tyr1666Ter and BRCA2:p.Ser1341Ter) have not been previously documented in the literature. Seven out of 19 patient’s relatives had BRCA1/2 gene mutations. All selected patients were counselled about the likelihood of cancer rising and prophylactic screening and procedures. The study established a risk score associated with the cohorts based on carrier status and family history; (4) Conclusions: Our findings suggested the implications for the planning of a screening programme for BRCA1 and BRCA2 genes testing in breast and ovarian cancer patients and genetic screening in their relatives. BRCA1/2 mutation carriers without cancer should have early and regular cancer screening, and prophylactic measures. This study could be beneficial for a diverse group in a large population-specific cohort, related to HBOC Syndrome.
Family based and case–control designs reveal an association of TFAP2A in nonsyndromic cleft lip only among Vietnamese population
Aims Dozens of causative genes and their mechanisms of nonsyndromic cleft lip with or without cleft palate (NSCL/P) were revealed through genome‐wide association and linkage studies. Results were, however, not always replicated in different populations or methodologies. This study used case–control and family based approaches to investigate the etiology of NSCL/P and its two subtypes: nonsyndromic cleft lip only (NSCLO) and nonsyndromic cleft lip and palate (NSCLP) among the Vietnamese population. Methods Two hundred and seventeen NSCL/P case‐parent trios (one affected child and two parents), including 105 NSCLO and 112 NSCLP were involved for a family based design; and 273 ethnic and region‐matched healthy controls with no cleft history in their families were recruited for a case–control design. Three SNPs consisting of TFAP2A (rs1675414 and rs303048) and 8q24 (rs987525) were genotyped using the TaqMan SNP genotyping assay. Results TFAP2A rs1675414 was associated with NSCLO, replicated by both case‐control and family based tests. Other SNPs yielded no evidence of susceptibility to NSCL/P or two subtypes. Conclusion The current investigation suggests an intriguing role of TFAP2A in the etiology of NSCLO among the Vietnamese population. This study used case‐control and family‐based approaches to investigate the etiology of NSCL/P and its two subtypes: nonsyndromic cleft lip only (NSCLO), nonsyndromic cleft lip and palate (NSCLP) among Vietnamese population. TFAP2A rs1675414 was associated with NSCLO, replicated by both case‐control and family‐based tests.
In silico validation revealed the role of SCN5A mutations and their genotype–phenotype correlations in Brugada syndrome
Background Brugada syndrome (BrS) is a rare genetic disease that causes sudden cardiac death (SCD) and arrhythmia. SCN5A pathogenic variants (about 30% of diagnosed patients) are responsible for BrS. Aims Lack of knowledge regarding molecular characteristics and the correlation between genotype and phenotype interfere with the risk stratification and finding the optimal treatment in Vietnam. Therefore, we identified SCN5A variants and evaluated the genotype–phenotype correlation of BrS on 117 Vietnamese probands. Materials and Methods The clinical characteristics and blood samples of BrS patients were collected. To determine SCN5A variants, Sanger sequencing was conducted, and subsequently, these variants were analyzed by bioinformatic tools. Results In this cohort, the overall rate of detected variants in SCN5A was 25.6%, which could include both pathogenic and benign variants. In genetic testing, 21 SCN5A variants were identified, including eight novels and 15 published variants. Multiple bioinformatic tools were used to predict variant effect with c.551A>G, c.1890+14G>A, c.3338C>T, c.3578G>A, and c.5484C>T as benign, while other variants were predicted as disease‐causing. The family history of SCD (risk ratio [RR] = 4.324, 95% CI: 2.290–8.269, p < 0.001), syncope (RR = 3.147, 95% CI: 1.668–5.982, p = 0.0004), and ventricular tachycardia/ventricular fibrillation (RR = 3.406, 95% CI: 1.722–5.400, p = 0.0035) presented a significantly higher risk in the SCN5A (+) group, consisting of individuals carrying any variant in the SCN5A gene, compared to SCN5A (−) individuals. Conclusion The results contribute to clarifying the impact of SCN5A variants on these phenotypes. Further follow‐up studies need to be carried out to understand the functional effects of these SCN5A variants on the severity of BrS. This study aims to identify SCN5A variants and evaluate the genotype‐phenotype correlation of Brugada syndrome on 117 Vietnamese probands. Multiple bioinformatic tools were carried out to classify SCN5A variants as benign and disease‐causing. In addition, the genotype‐phenotype correlation was also revealed.
Mutation spectrum of retinoblastoma patients in Vietnam
Retinoblastoma (RB), an intraocular malignancy commonly diagnosed in children, is mostly caused by inactivating mutations of both alleles of the RB1 gene. Early genetic screening for RB1 gene mutations would greatly improve treatment outcomes and patient management. In this study, both somatic and germline mutations were detected in blood and tumour samples of 42 RB patients using direct sequencing and multiplex ligation-dependent probe amplification. In total, 34 different mutations were found in 36 patients, including 1 SNP, 4 large deletions, 5 splicing sites, 1 missense, 7 frameshifts and 17 nonsense mutations. There were five novel mutations and one unreported which have not been found in large databases such as Leiden Open Variation Database (LOVD) and ClinVar. A higher rate of RB patients carrying heterozygous germline mutation and highly prevalent with pathogenic truncated mutation, hence, early detection of RB is essential for vision salvation and genetic counselling.
All-Digital Background Calibration Technique for Offset, Gain and Timing Mismatches in Time-Interleaved ADCs
This paper presents a method for all-digital background calibration of multiple channel mismatches including offset, gain and timing mismatches in time-interleaved analog to digital converters (TIADCs). The averaging technique is used to remove the offset mismatch at each channel. The gain mismatch is calibrated by calculating the power ratio of the subADC over the reference ADC. Timing skew is compensated by using Hadamard transform for error correction and least mean squares (LMS) algorithm for estimation of the clock skew. The performance improvement of TIADCs employing these techniques is demonstrated through numerical simulations.
The Impact of Vaccination on COVID-19 Outcomes in Vietnam
Objectives: This study aimed to assess the effectiveness of the COVID-19 vaccine on the outcomes of patients in three hospitals in Vietnam. Methods: An observational study involved 3102 confirmed COVID-19 patients from Vietnam. Participants were classified into unvaccinated, partially vaccinated (one dose) (PV), fully vaccinated (two doses) (FV), and boosted (three doses) groups. We used a regression model to assess the relationship between vaccine status and disease outcome, including mortality, persistent symptoms after treatment, and hospital duration. Results: The proportions of unvaccinated, PV, FV, and boosted groups were 43.39%, 4.63%, 43.93%, and 8.05%, respectively, and 48% of the participants had at least one comorbidity. The proportion of severe clinical disease was significantly higher in the unvaccinated compared with the vaccinated. Biomarkers of cellular injury and organ failure, e.g., aspartate aminotransferase (AST), ferritin, troponin T, proBNP, D-dimer, and urea plasma concentration were significantly higher in unvaccinated and PV patients compared with FV and boosted patients. Age was the most crucial predictor of critical illness, followed by vaccine status, hypertension, diabetes, heart disease, and chronic kidney disease. The unvaccinated group had the highest proportion of deaths (5.2% vs. 1.4% and 0.3% in FV and boosted groups, respectively). Conclusions: Vaccination reduced mortality and both hospitalization length and disease severity in COVID-19 survivors, especially the older and patients with chronic comorbidities.