Feasibility of full-spectrum endoscopy: Korea's first full-spectrum endoscopy colonoscopic trial.

AIM: To evaluate the full-spectrum endoscopy (FUSE) colonoscopy system as the first report on the utility thereof in a Korean population. METHODS: We explored the efficacy of the FUSE colonoscopy in a retrospective, single-center feasibility study performed between February 1 and July 20, 2015. A total of 262 subjects (age range: 22-80) underwent the FUSE colonoscopy for colorectal cancer screening, polyp surveillance, or diagnostic evaluation. The cecal intubation success rate, the polyp detection rate (PDR), the adenoma detection rate (ADR), and the diverticulum detection rate (DDR), were calculated. Also, the success rates of therapeutic interventions were evaluated with biopsy confirmation. RESULTS: All patients completed the study and the success rates of cecal and terminal ileal intubation were 100% with the FUSE colonoscope; we found 313 polyps in 142 patients and 173 adenomas in 95. The overall PDR, ADR and DDR were 54.2%, 36.3%, and 25.2%, respectively, and were higher in males, and increased with age. The endoscopists and nurses involved considered that the full-spectrum colonoscope improved navigation and orientation within the colon. No colonoscopy was aborted because of colonoscope malfunction. CONCLUSION: The FUSE colonoscopy yielded a higher PDR, ADR, DDR than did traditional colonoscopy, without therapeutic failure or complications, showing feasible, effective, and safe in this first Korean trial.

Effects of combined oleic acid and fluoride at sub-MIC levels on EPS formation and viability of Streptococcus mutans UA159 biofilms.

Despite the widespread use of fluoride, dental caries, a biofilm-related disease, remains an important health problem. This study investigated whether oleic acid, a monounsaturated fatty acid, can enhance the effect of fluoride on extracellular polysaccharide (EPS) formation by Streptococcus mutans UA159 biofilms at sub-minimum inhibitory concentration levels, via microbiological and biochemical methods, confocal fluorescence microscopy, and real-time PCR. The combination of oleic acid with fluoride inhibited EPS formation more strongly than did fluoride or oleic acid alone. The superior inhibition of EPS formation was due to the combination of the inhibitory effects of oleic acid and fluoride against glucosyltransferases (GTFs) and GTF-related gene (gtfB, gtfC, and gtfD) expression, respectively. In addition, the combination of oleic acid with fluoride altered the bacterial biovolume of the biofilms without bactericidal activity. These results suggest that oleic acid may be useful for enhancing fluoride inhibition of EPS formation by S. mutans biofilms, without killing the bacterium.

Analysis of the dihydrofolate reductase-thymidylate synthase gene sequences in Plasmodium vivax field isolates that failed chloroquine treatment.

BACKGROUND: To use pyrimethamine as an alternative anti-malarial drug for chloroquine-resistant malaria parasites, it was necessary to determine the enzyme's genetic variation in dihydrofolate reductase-thymidylate syntase (DHFR-TS) among Korean strains. METHODS: Genetic variation of dhfr-ts genes of Plasmodium vivax clinical isolates from patients who did not respond to drug treatment (n = 11) in Korea were analysed. The genes were amplified using the polymerase chain reaction (PCR) with genomic DNA as a template. RESULTS: Sequence analysis showed that the open reading frame (ORF) of 1,857 nucleotides encoded a deduced protein of 618 amino acids (aa). Alignment with the DHFR-TS genes of other malaria parasites showed that a 231-residue DHFR domain and a 286-residue TS domain were seperated by a 101-aa linker region. This ORF shows 98.7% homology with the P. vivax Sal I strain (XM001615032) in the DHFR domain, 100% in the linker region and 99% in the TS domain. Comparison of the DHFR sequences from pyrimethamine-sensitive and pyrimethamine-resistant P. vivax isolates revealed that nine isolates belonged to the sensitive strain, whereas two isolates met the criteria for resistance. In these two isolates, the amino acid at position 117 is changed from serine to asparagine (S117N). Additionally, all Korean isolates showed a deletion mutant of THGGDN in short tandem repetitive sequences between 88 and 106 amino acid. CONCLUSIONS: These results suggest that sequence variations in the DHFR-TS represent the prevalence of antifolate-resistant P. vivax in Korea. Two of 11 isolates have the Ser to Asn mutation in codon 117, which is the major determinant of pyrimethamine resistance in P. vivax. Therefore, the introduction of pyrimethamine for the treatment of chloroquine-resistant vivax malaria as alternative drug in Korea should be seriously considered.

Production of quail (Coturnix japonica) germline chimeras derived from in vitro-cultured gonadal primordial germ cells.

A previous report from our laboratory documented successful production of quail (Coturnix japonica) germline chimeras by transfer of gonadal primordial germ cells (gPGCs). Subsequently, this study was designed to evaluate whether gPGCs can be maintained in vitro for extended period, and furthermore, these cultured PGCs can induce germline transmission after transfer into recipient embryos. In experiment 1, gonadal cells from the two strains (wild-type plumage (WP) and black (D) quail) were cultured in vitro for 10 days. Using antibody QCR1, we detected a continuous, significant (P = 0.0002) increase in the number of WP, but not D, PGCs. QCR1-positive WP colonies began to form after 7 days in culture. On Day 10 of culture, 803 WP PGCs were present as a result of a continuous increase, whereas no D PGC colonies could be detected and the D gonadal stroma cells were rolled up. Differences in the PGCs or the gonadal stroma cells of the two different strains might account for these differences. In experiment 2, WP PGC colonies were maintained in vitro up to Day 20 of culture, and 10- or 20-day-cultured PGCs were microinjected into dorsal aortas of 181 recipient D embryos. Thirty-five (19.3%) of the transplanted embryos hatched after incubation, and 25 (71.4%) of the hatchlings reached sexual maturity. Testcrossing of the sexually mature hatchlings resulted in three (10 days, 33.3%) and eight (20 days, 50.0%) germline chimeras respectively. This report is the first to describe successful production of germline chimera by transfer of in vitro-cultured gPGCs in quail.

MPSS profiling of embryonic gonad and primordial germ cells in chicken.

The massively parallel signature sequencing (MPSS) provides a greater depth of coverage than expressed sequence tag scan or microarray and provides a comprehensive expression profile. We used the MPSS technology to uncover gene expression profiling in the early embryonic gonads and primordial germ cells (PGCs) in the chicken. Total numbers of sequenced signatures were 1,012,533 and 995,676 for the PGCs and gonad, respectively. Using a noise distribution model, we found that 1.67% of all signatures are expressed at a higher level in PCGs and 2.81% of all signatures are expressed at a higher level in the gonad. The MPSS data are presented via an interactive web interface available at http://snugenome.snu.ac.kr/MPSS. The MPSS data have been submitted to the Gene Expression Omnibus of the National Center for Biotechnology Information (accession number GSM137300 and GSM137301 for PGCs and gonad, respectively).

Gene expression profiling of chicken primordial germ cell ESTs.

BACKGROUND: Germ cells are the only cell type that can penetrate from one generation to next generation. At the early embryonic developmental stages, germ cells originally stem from primordial germ cells, and finally differentiate into functional gametes, sperm in male or oocyte in female, after sexual maturity. This study was conducted to investigate a large-scale expressed sequence tag (EST) analysis in chicken PGCs and compare the expression of the PGC ESTs with that of embryonic gonad. RESULTS: We constructed 10,851 ESTs from a chicken cDNA library of a collection of highly separated embryonic PGCs. After chimeric and problematic sequences were filtered out using the chicken genomic sequences, there were 5,093 resulting unique sequences consisting of 156 contigs and 4,937 singlets. Pearson chi-square tests of gene ontology terms in the 2nd level between PGC and embryonic gonad set showed no significance. However, digital gene expression profiling using the Audic's test showed that there were 2 genes expressed significantly with higher number of transcripts in PGCs compared with the embryonic gonads set. On the other hand, 17 genes in embryonic gonads were up-regulated higher than those in the PGC set. CONCLUSION: Our results in this study contribute to knowledge of mining novel transcripts and genes involved in germline cell proliferation and differentiation at the early embryonic stages.

Production of quail (Coturnix japonica) germline chimeras by transfer of gonadal primordial germ cells into recipient embryos.

The possibility of producing quail germline chimeras by the transfer of gonadal primordial germ cells (gPGCs) into recipient embryos was investigated. Japanese quail of the black (D: homozygous for the autosomal incomplete dominant gene D) and wild-type plumage (WP: d+/d+) strains were used as donors and recipients, respectively. Gonadal cells were retrieved from the gonads of 5-day-old D embryos, and gPGCs were enriched by magnetism-activated cell sorting. Fresh (noncultured) gPGCs or those isolated after culture for 3 days with gonadal stromal cells present in the mixed cell population were introduced into the dorsal aorta of 2-day-old recipient WP embryos. Hatchability of the recipient embryos was 23.7% (31/131) and 34.4% (31/90) for those transfused with cultured or noncultured gPGCs, respectively. Of the hatched quail, 28 acquired sexual maturity; among these animals, 7.1% (1/14) and 21.4% (3/14) of those that received cultured or noncultured gPGCs, respectively, were proved to be germline chimeras. The percentage of germline transmission to the donor-derived gametes in the chimeras that received cultured and noncultured gPGCs were 1.9 and 2.2-4.7%, respectively. In conclusion, quail gPGCs retrieved from 5-day-old embryos were thus transmitted in the germline after their transfer to quail embryos of a different strain. This property of the gPGCs was not adversely affected by culture for up to 3 days.

Enriched gonadal migration of donor-derived gonadal primordial germ cells by immunomagnetic cell sorting in birds.

This study was conducted to evaluate whether immunomagnetic treatment could improve the retrieval and migration capacity of avian gonadal primordial germ cells (gPGCs) collected from gonads in 5.5-day-old chick and 5-day-old quail embryos, respectively. Collected gPGCs were loaded into a magnetic-activated cell sorter (MACS) after being conjugated with specific gPGC antibodies and either MACS-treated or non-treated cells in each species were subsequently transferred to the recipient embryos. MACS treatment significantly (P < 0.05) increased the population ratio of gPGCs in gonadal cells retrieved (0.74 to 33.4% in the chicken and 2.68 to 45.1% in the quail). This was due to decreased number of non-gPGCs in total cell population. MACS treatment further enhanced gonadal migration of gPGCs transferred in both species (10% vs. 80-85% in the chicken and 10-15% vs. 70-80% in the quail). Increase in the number of microinjected cells up to 600 cells/embryo did not eliminate such promoting effect. In conclusion, MACS treatment greatly increased the population ratio of avian gPGCs in gonadal cells, resulting improved gonadal migration in recipient embryos.