Background: The 16S rRNA-targeted next-generation sequencing (NGS) has been widely used as the primary tool for microbiome analysis. However, whether the sequenced microbial diversity absolutely represents the original sample composition remains unclear. This study aimed to evaluate whether 16S rRNA gene-targeted NGS accurately captures bacterial community composition. Methods: Mock communities were constructed using equal amounts of DNA from 18 bacterial strains in three formats: genomic DNA, recombinant plasmids, and polymerase chain reaction (PCR) templates. The V3V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq. Results: Data regression analysis revealed that the recombinant plasmid produced more accurate and precise correlation curve than that by the gDNA and PCR products, with a slope closest to 1 (1.0082) and the highest R² value (0.9975). Despite the same input amount of bacterial DNA, the NGS read distribution varied across all three mock communities. Using multiple regression analysis, we found that the guanine-cytosine (GC) content of the V3V4 region, 16S rRNA gene, size of gDNA, and copy number of 16S rRNA were significantly associated with the NGS output of each bacterial species. Conclusion This study demonstrated that recombinant plasmids are the preferred option for quality control and that NGS output is biased owing to certain bacterial characteristics, such as %GC content, gDNA size, and 16S rRNA gene copy number. Further research is required to develop a system that compensates for NGS process biases using mock communities.

Background: The 16S rRNA-targeted next-generation sequencing (NGS) has been widely used as the primary tool for microbiome analysis. However, whether the sequenced microbial diversity absolutely represents the original sample composition remains unclear. This study aimed to evaluate whether 16S rRNA gene-targeted NGS accurately captures bacterial community composition. Methods: Mock communities were constructed using equal amounts of DNA from 18 bacterial strains in three formats: genomic DNA, recombinant plasmids, and polymerase chain reaction (PCR) templates. The V3V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq. Results: Data regression analysis revealed that the recombinant plasmid produced more accurate and precise correlation curve than that by the gDNA and PCR products, with a slope closest to 1 (1.0082) and the highest R² value (0.9975). Despite the same input amount of bacterial DNA, the NGS read distribution varied across all three mock communities. Using multiple regression analysis, we found that the guanine-cytosine (GC) content of the V3V4 region, 16S rRNA gene, size of gDNA, and copy number of 16S rRNA were significantly associated with the NGS output of each bacterial species. Conclusion This study demonstrated that recombinant plasmids are the preferred option for quality control and that NGS output is biased owing to certain bacterial characteristics, such as %GC content, gDNA size, and 16S rRNA gene copy number. Further research is required to develop a system that compensates for NGS process biases using mock communities.

Background: The 16S rRNA-targeted next-generation sequencing (NGS) has been widely used as the primary tool for microbiome analysis. However, whether the sequenced microbial diversity absolutely represents the original sample composition remains unclear. This study aimed to evaluate whether 16S rRNA gene-targeted NGS accurately captures bacterial community composition. Methods: Mock communities were constructed using equal amounts of DNA from 18 bacterial strains in three formats: genomic DNA, recombinant plasmids, and polymerase chain reaction (PCR) templates. The V3V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq. Results: Data regression analysis revealed that the recombinant plasmid produced more accurate and precise correlation curve than that by the gDNA and PCR products, with a slope closest to 1 (1.0082) and the highest R² value (0.9975). Despite the same input amount of bacterial DNA, the NGS read distribution varied across all three mock communities. Using multiple regression analysis, we found that the guanine-cytosine (GC) content of the V3V4 region, 16S rRNA gene, size of gDNA, and copy number of 16S rRNA were significantly associated with the NGS output of each bacterial species. Conclusion This study demonstrated that recombinant plasmids are the preferred option for quality control and that NGS output is biased owing to certain bacterial characteristics, such as %GC content, gDNA size, and 16S rRNA gene copy number. Further research is required to develop a system that compensates for NGS process biases using mock communities.

Background: The 16S rRNA-targeted next-generation sequencing (NGS) has been widely used as the primary tool for microbiome analysis. However, whether the sequenced microbial diversity absolutely represents the original sample composition remains unclear. This study aimed to evaluate whether 16S rRNA gene-targeted NGS accurately captures bacterial community composition. Methods: Mock communities were constructed using equal amounts of DNA from 18 bacterial strains in three formats: genomic DNA, recombinant plasmids, and polymerase chain reaction (PCR) templates. The V3V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq. Results: Data regression analysis revealed that the recombinant plasmid produced more accurate and precise correlation curve than that by the gDNA and PCR products, with a slope closest to 1 (1.0082) and the highest R² value (0.9975). Despite the same input amount of bacterial DNA, the NGS read distribution varied across all three mock communities. Using multiple regression analysis, we found that the guanine-cytosine (GC) content of the V3V4 region, 16S rRNA gene, size of gDNA, and copy number of 16S rRNA were significantly associated with the NGS output of each bacterial species. Conclusion This study demonstrated that recombinant plasmids are the preferred option for quality control and that NGS output is biased owing to certain bacterial characteristics, such as %GC content, gDNA size, and 16S rRNA gene copy number. Further research is required to develop a system that compensates for NGS process biases using mock communities.

Background: The 16S rRNA-targeted next-generation sequencing (NGS) has been widely used as the primary tool for microbiome analysis. However, whether the sequenced microbial diversity absolutely represents the original sample composition remains unclear. This study aimed to evaluate whether 16S rRNA gene-targeted NGS accurately captures bacterial community composition. Methods: Mock communities were constructed using equal amounts of DNA from 18 bacterial strains in three formats: genomic DNA, recombinant plasmids, and polymerase chain reaction (PCR) templates. The V3V4 region of the 16S rRNA gene was amplified and sequenced using the Illumina MiSeq. Results: Data regression analysis revealed that the recombinant plasmid produced more accurate and precise correlation curve than that by the gDNA and PCR products, with a slope closest to 1 (1.0082) and the highest R² value (0.9975). Despite the same input amount of bacterial DNA, the NGS read distribution varied across all three mock communities. Using multiple regression analysis, we found that the guanine-cytosine (GC) content of the V3V4 region, 16S rRNA gene, size of gDNA, and copy number of 16S rRNA were significantly associated with the NGS output of each bacterial species. Conclusion This study demonstrated that recombinant plasmids are the preferred option for quality control and that NGS output is biased owing to certain bacterial characteristics, such as %GC content, gDNA size, and 16S rRNA gene copy number. Further research is required to develop a system that compensates for NGS process biases using mock communities.

BACKGROUND: This study aimed to assess the outcome of stem cell transplantation (SCT), including overall survival (OS), failure-free survival (FFS) and graft-versus-host disease (GvHD)-free/failure-free survival (GFFS), and to analyze prognostic factors in children with aplastic anemia (AA).METHODS: From 1991 to 2018, 43 allogeneic SCT recipients were enrolled in the study to investigate the demographic characteristics, survival outcomes and prognostic factors.RESULTS: With the median follow-up of 7.1 years, the estimated 10-year OS, FFS, GFFS were 86.0%, 60.5%, and 51.2%, respectively. Matched related donors (MRD, n = 28) showed better 10-year OS than unrelated donors (n = 15) (96.4% vs. 66.7%; P = 0.006). Engraftment failure was seen in 13 patients (30.2%). Donor-type aplasia was seen in 13.8% (4/29) after fludarabine (Flu)-based conditioning (Flu-group), while in 42.6% (6/14) after cyclophosphamide (Cy)-based regimen (Cy-group) (P = 0.035). Six patients died. The 10-year OS in Cy-group was 92.9% (n = 14, all MRD), while that of Flu-group was 82.1% (n = 29; P = 0.367). But Flu-group tended to have better FFS and GFFS than Cy-group, although Flu-group had less MRDs (41.4% vs. 100%; P = 0.019), and higher proportion of previous immunosuppressive treatment (IST; 62% vs. 21.4%, P = 0.012). In MRD transplants, OS was similar between Flu-group (100%, n = 14) and Cy-group (92.9%, n = 14), while FFS (100.0% vs. 42.9%; P = 0.001) and GFFS (85.7% vs. 35.7%; P = 0.006) were significantly better in Flu-group. Stem cell sources, irradiation in the conditioning, and method of GvHD prophylaxis did not significantly influence the outcome.CONCLUSION: This study reviewed SCT outcomes for pediatric AA with changes of transplant strategies over the last 25 years. The FFS and GFFS were higher in Flu-group than in Cy-group, especially in matched related transplantation. Graft failure including donor-type aplasia remains troublesome even with Flu-based conditioning. Further refinement of transplant strategies to ensure better quality-of-life should be pursued.
Anemia, Aplastic ; Child ; Cyclophosphamide ; Follow-Up Studies ; Graft vs Host Disease ; Humans ; Methods ; Stem Cell Transplantation ; Stem Cells ; Tissue Donors ; Transplants ; Unrelated Donors

Background: Rixubis (recombinant factor IX, nonacog gamma) is indicated for the control and prevention of bleeding episodes, perioperative management, and routine prophylaxis in hemophilia B patients. This real-world, postmarketing surveillance study aimed to evaluate the safety and effectiveness of Rixubis in adult and pediatric hemophilia B patients in South Korea. Methods: This prospective, observational, multicenter study (clinicaltrials.gov identifier: NCT029 22231) was conducted in hemophilia B patients between April 2015 and April 2019, who were observed for up to 6 months after the initiation of Rixubis treatment. Safety was evaluated based on the number and severity of adverse events (AEs) and serious AEs (SAEs). Hemostatic effectiveness was assessed by physicians and patients by using a four-point scale and rated as excellent, good, fair, or no response based on treatment type. Results: In all, 58 patients were enrolled from four centers by seven physicians during the study period. The safety and effectiveness analysis sets included 57 and 54 patients, respectively. Overall, 11 AEs were reported in eight patients (14.0%), of which three were SAEs and occurred in three patients (5.3%). All 11 AEs were reported as unexpected and mild in severity, with no anaphylactic reaction, and 10 AEs (90.9%) resolved. The majority of AEs (10) were unrelated to Rixubis. Of the 142 hemostatic effectiveness assessments, 123 (86.6%) were reported as good or excellent. Conclusion Rixubis demonstrated an acceptable safety and effectiveness profile in the treatment of bleeding, perioperative management, and prophylaxis in hemophilia B patients in a real-world setting in South Korea.

BACKGROUND: This study aimed to assess the outcome of stem cell transplantation (SCT), including overall survival (OS), failure-free survival (FFS) and graft-versus-host disease (GvHD)-free/failure-free survival (GFFS), and to analyze prognostic factors in children with aplastic anemia (AA). METHODS: From 1991 to 2018, 43 allogeneic SCT recipients were enrolled in the study to investigate the demographic characteristics, survival outcomes and prognostic factors. RESULTS: With the median follow-up of 7.1 years, the estimated 10-year OS, FFS, GFFS were 86.0%, 60.5%, and 51.2%, respectively. Matched related donors (MRD, n = 28) showed better 10-year OS than unrelated donors (n = 15) (96.4% vs. 66.7%; P = 0.006). Engraftment failure was seen in 13 patients (30.2%). Donor-type aplasia was seen in 13.8% (4/29) after fludarabine (Flu)-based conditioning (Flu-group), while in 42.6% (6/14) after cyclophosphamide (Cy)-based regimen (Cy-group) (P = 0.035). Six patients died. The 10-year OS in Cy-group was 92.9% (n = 14, all MRD), while that of Flu-group was 82.1% (n = 29; P = 0.367). But Flu-group tended to have better FFS and GFFS than Cy-group, although Flu-group had less MRDs (41.4% vs. 100%; P = 0.019), and higher proportion of previous immunosuppressive treatment (IST; 62% vs. 21.4%, P = 0.012). In MRD transplants, OS was similar between Flu-group (100%, n = 14) and Cy-group (92.9%, n = 14), while FFS (100.0% vs. 42.9%; P = 0.001) and GFFS (85.7% vs. 35.7%; P = 0.006) were significantly better in Flu-group. Stem cell sources, irradiation in the conditioning, and method of GvHD prophylaxis did not significantly influence the outcome. CONCLUSION This study reviewed SCT outcomes for pediatric AA with changes of transplant strategies over the last 25 years. The FFS and GFFS were higher in Flu-group than in Cy-group, especially in matched related transplantation. Graft failure including donor-type aplasia remains troublesome even with Flu-based conditioning. Further refinement of transplant strategies to ensure better quality-of-life should be pursued.

BACKGROUND: Acute leukemia (AL), not clearly assigned to myeloid, B-lymphoid, or T-lymphoid lineage, is classified as either biphenotypic acute leukemia (BAL) based on the European Group for Immunological Classification of Leukemias (EGIL) or acute leukemia of ambiguous lineage (ALAL) encompassing acute undifferentiated leukemia (AUL) and mixed-phenotype acute leukemia (MPAL) based on the World Health Organization (WHO) criteria. METHODS: Medical records of children newly diagnosed with BAL or ALAL, based on the EGIL or the 2008/2016 WHO criteria, respectively, admitted at Chonnam National University Hospital in 2001–2017 were retrospectively reviewed. RESULTS: Twelve (3.2%) of 377 AL patients satisfied the BAL or ALAL definitions based on the EGIL or the WHO criteria, respectively. Among 12 patients including 11 with BAL and another with undefined case based on the EGIL criteria, 7 (1.9%) had ALAL based on more stringent 2016 WHO criteria (AUL, 2; MPAL, 5). One patient had MPAL with t(9;22)(q34;q11.2), BCR-ABL+, and two had MLL gene abnormality. ALL-directed regimen was associated with better complete remission rate compared with AML-directed regimen (100.0% vs. 16.7%; P=0.015). The 5-year overall survival (OS) and event-free survival (EFS) were 51.1±15.8% and 51.9±15.7%, respectively. AUL was associated with poor OS and EFS compared with MPAL (0.0% vs. 75.0±21.7%; P=0.008). CONCLUSION: Due to the rarity of the cases, future multicenter, prospective studies incorporating large number of cases are urgently warranted to identify the clinical, biologic, and molecular markers for the prediction of prognosis and determine the best tailored therapy for each patient.
Child ; Classification ; Disease-Free Survival ; Humans ; Immunophenotyping ; Jeollanam-do ; Leukemia ; Leukemia, Biphenotypic, Acute ; Medical Records ; Prognosis ; Prospective Studies ; Retrospective Studies ; World Health Organization

Dogs serve human society in various ways by working at tasks that are based on their superior olfactory sensitivity. However, it has been reported that only about half of all trained dogs may qualify as working dogs through conventional breeding management because proper temperament and health are needed in addition to their innate scent detection ability. To overcome this low efficiency of breeding qualified working dogs, and to reduce the enormous costs of maintaining unqualified dogs, somatic cell nuclear transfer has been applied in the propagation of working dogs. Herein, we review the history of cloning working dogs and evaluate the health development, temperaments, and behavioral similarities among the cloned dogs. We also discuss concerns about dog cloning including those related to birth defects, lifespan, and cloning efficiency.
Animals ; Breeding ; Clone Cells ; Cloning, Organism ; Congenital Abnormalities ; Dogs ; Humans ; Temperament