Biomedical subjects

H-J Yoon

Publications and source records attributed to H-J Yoon.

7 recordsLinked to original sources

PubMed2004

A novel small-molecule inhibitor of the chromosome segregation process in yeast.

The centromeres of budding yeasts contain specific and essential DNA sequences, in contrast to the regional heterochromatic centromeres found in higher organisms. Small molecules that perturb centromere function in budding yeast could be valuable candidates for identifying yeast-specific growth inhibitors. A combination of two in vivo assays, one based on transcription blockade of a reporter gene by the centromeric DNA-protein complex, the other on a test for mitotic minichromosome stability, was used to identify small molecules that affect the process of chromosome segregation. One compound, here named incentrom A, leads to a minichromosome loss phenotype, and is cytotoxic to the budding yeast Saccharomyces cerevisiae. Furthermore, whereas cells carrying a conditional mutation in a gene for an essential kinetochore protein, skp1-4, are hypersensitive to incentrom A, cells that overexpress the SKP1 gene are resistant to the compound. Incentrom A also results in mitotic loss of a centromere-bearing plasmid, and inhibits the growth of the pathogenic yeast Candida glabrata. Incentrom A will therefore be a useful tool for studying the molecular basis of yeast chromosome segregation and could form the basis for the development of novel antifungal drugs.

Candida glabrata↗

PubMed2003

Comparison of general and epidural anesthesia in elective cesarean section for placenta previa totalis: maternal hemodynamics, blood loss and neonatal outcome.

There are few consistent guidelines in choosing anesthesia for cesarean section for a parturient with placenta previa. This prospective randomized trial was organized to compare the maternal hemodynamics, blood loss and neonatal outcome of general versus epidural anesthesia for cesarean section with the diagnosis of grade 4 placenta previa. After giving informed consent, 12 patients received general anesthesia and 13 received epidural. Intraoperative blood pressures demonstrated a more stable course in the epidural group than in the general group. Blood loss did not differ significantly between the groups (1622 +/- 775 mL vs. 1418 +/- 996 mL). General anesthesia resulted in lower immediate postoperative hematocrit level (28.1 +/- 3.5% vs. 32.5 +/- 5.0%, P < 0.05). The patients in the general group received a significantly larger transfusion than the epidural group (1.08 +/- 1.6 vs. 0.38 +/- 0.9 units, P < 0.05). The Apgar scores at 1 and 5 min were similar in the two groups (8 [4-9] vs. 8 [7-9] and 10 [6-10] vs. 9 [9-10], respectively). We concluded that epidural anesthesia is superior to general anesthesia in elective cesarean section for grade 4 placenta previa with regard to maternal hemodynamics and blood loss. There was no difference in neonatal outcome.

Journal Article↗

PubMed2003

The TB structural genomics consortium: a resource for Mycobacterium tuberculosis biology.

The TB Structural Genomics Consortium is an organization devoted to encouraging, coordinating, and facilitating the determination and analysis of structures of proteins from Mycobacterium tuberculosis. The Consortium members hope to work together with other M. tuberculosis researchers to identify M. tuberculosis proteins for which structural information could provide important biological information, to analyze and interpret structures of M. tuberculosis proteins, and to work collaboratively to test ideas about M. tuberculosis protein function that are suggested by structure or related to structural information. This review describes the TB Structural Genomics Consortium and some of the proteins for which the Consortium is in the progress of determining three-dimensional structures.

Amino Acid Sequence↗

PubMed2003

Association of the CD14 gene -159C polymorphism with progression of IgA nephropathy.

The risk factors associated with the progression of IgA nephropathy (IgAN), the most common form of glomerulonephritis, are unclear. It has been suggested that CD14 signalling in response to various microbes affects the natural history of chronic inflammatory conditions. It has been hypothesised that variants in the promoter region of the CD14 gene might alter the expression of CD14, and this in turn could influence the progressive nature of IgAN. PCR-RFLP was used to determine the polymorphism at the -159 site (T to C). The distribution of the CD14/-159 polymorphism was no different in patients with IgAN (n=216) compared to 171 healthy controls. After follow up for 86 months, it was found that an excess of the C genotype occurred in patients with progressive disease (p=0.03) and the risk of disease progression increased as the number of C alleles increased (p for trend = 0.002). The hazard ratio for progression in the patients with the CC genotype was 3.2 (p=0.025) compared with the patients possessing the TT genotype. After LPS stimulation, sCD14 was released more abundantly from the PBMCs of the TT subjects than from that of the CC subjects (p=0.006), even though mCD14 expression level was no different. In addition, the TT subjects released less IL-6 than the CC subjects after stimulation (p=0.0003). These results suggest that the CD14/-159 polymorphism is an important marker for the progression of IgAN and may modulate the level of the inflammatory responses.

Adult↗

PubMed2002

Interdependent effect of angiotensin-converting enzyme and platelet-activating factor acetylhydrolase gene polymorphisms on the progression of immunoglobulin A nephropathy.

In order to investigate the interdependent action of the insertion/deletion polymorphism of the angiotensin-converting enzyme (ACE) gene and polymorphism in exon 11 (C1136-->T; Ala379Val) of the platelet-activating factor acetylhydrolase (PAF-AH) gene, which encodes a functional antagonist of PAF, on the progression of immunoglobulin A (IgA) nephropathy, we analysed both polymorphisms in patients with primary IgA nephropathy, who were followed-up for longer than 3 years. During the follow-up (87.3 +/- 50.0 months), the disease progressed in 38 of the 191 patients (19.9%). The D allele of the ACE gene in the absence of the T allele of the PAF-AH gene did not affect the prognosis [odds ratio (OR), 3.6; 95% confidence interval (CI), 0.8-16.4] and neither did the T allele in the absence of the D allele (OR, 3.0; 95% CI, 0.4-24.2). However, the presence of both was a significant prognostic factor (OR, 6.6; 95% CI, 1.4-31.3). After adjusting for other risk factors, the presence of both proved to be an independent risk factor (OR, 4.5; 95% CI, 1.6-12.7). These results suggest that the interdependent effects of ACE and PAF-AH polymorphisms on the progression of IgA nephropathy might be more important than the effect of the individual polymorphisms.

1-Alkyl-2-acetylglycerophosphocholine Esterase↗

PubMed2002

Diagnostic survey of bovine abortion in Korea: with special emphasis on Neospora caninum.

Causes of bovine abortion were surveyed in Korea within a designated period from the cases submitted to the Department of Veterinary Pathology, College of Veterinary Medicine, Seoul National University. One hundred and eighty aborted fetuses and maternal sera were evaluated by necropsy, histopathology, bacteriology, virology, PCR, and serologic tests. The causes of abortion were identified in 108 (60%) cases, of which 38 (21.1%) were due to the infection with Neospora caninum. None of the 38 cases showed any co-infection with either virus or bacteria. Viral and bacterial causes were diagnosed in 28 (15.5%) and 13 (7.2%) aborted fetuses, respectively. Non-infectious causes such as multiple pregnancy, maternal weakness or torsion of umbilical cord were observed in 22 (12.3%) cases. Results of the present study suggest that N. caninum is believed to be the leading cause of bovine abortion in Korea. Thus, more attention should be paid to this emerging disease in Korea. However, the causes of many aborted fetuses remain undiagnosed in this study. Therefore, this enigma should be clarified through further studies such as chromosomal analysis.

Abortion, Veterinary↗

PubMed1999

Special cell surface structure, and novel macromolecule transport/depolymerization system of Sphingomonas sp A1.

A bacterium isolated from soil as an alginate lyase producer shows characteristic morphological and taxonomical properties consistent with being classified in the genus Sphingomonas. The bacterium utilizes high molecular weight (HMW)-alginate for growth by depolymerization of the polymer with intracellular alginate lyases, which are generated from a common precursor protein through autoregulated post-translational modifications. Electron microscopic observations of the cell surface and of thin sections of cells grown on HMW-alginate revealed dynamic changes in both cell surface and membrane structures. The most remarkable change is recognized in the formation of mouth-like pits which open and close depending on the presence or absence of HMW-alginate. Enzymatic and genetic analyses of HMW-alginate incorporation processes confirmed the presence of a pit-dependent and macromolecule-specific ABC transporter system in cells of Sphingomonas species A1. This is the first description of a bacterium with a pit on the cell surface and a pit-dependent endocytosic uptake system for macromolecules.

Journal Article↗