Biomedical subjects

Jae-Hyun Park

Publications and source records attributed to Jae-Hyun Park.

23 records · Page 2Linked to original sources

PubMed2003

Downregulation of FUSE-binding protein and c-myc by tRNA synthetase cofactor p38 is required for lung cell differentiation.

p38 is associated with a macromolecular tRNA synthetase complex. It has an essential role as a scaffold for the complex, and genetic disruption of p38 in mice causes neonatal lethality. Here we investigated the molecular mechanisms underlying lethality of p38-mutant mice. p38-deficient mice showed defects in lung differentiation and respiratory distress syndrome. p38 was found to interact with FUSE-binding protein (FBP), a transcriptional activator of c-myc. Binding of p38 stimulated ubiquitination and degradation of FBP, leading to downregulation of c-myc, which is required for differentiation of functional alveolar type II cells. Transforming growth factor-beta (TGF-beta) induced p38 expression and promoted its translocation to nuclei for the regulation of FBP and c-myc. Thus, this work identified a new activity of p38 as a mediator of TGF-beta signaling and its functional importance in the control of c-myc during lung differentiation.

Amino Acyl-tRNA Synthetases↗

PubMed2003

The effect of long-term aerobic exercise on maximal oxygen consumption, left ventricular function and serum lipids in elderly women.

The purpose of this study was to investigate the changes of maximal oxygen consumption, left ventricular function and serum lipids after 36 weeks of aerobic exercise in elderly women without the influence of drugs. Eight elderly women were studied by M-mode and Doppler echocardiography to assess left ventricular size, mass and function. Maximal oxygen consumption (VO(2)max) was determined for each subject by administering a treadmill exercise test. The training intensity was decided by heart rate reserve. Subjects performed exercise for 40 minutes a day, 3 days a week at 50-60% of the heart rate reserve during the 36 weeks. Exercise capacity was assessed by VO(2)max with a graded exercise test of the treadmill. Weight and % body fat decreased after training. Cardiorespiratory function improved because of the increase in VO(2)max and VO(2)max normalized for body weight after training. Systolic blood pressure significantly decreased. There are no significant difference in all left ventricular's parameters (end-diastolic dimension, end-systolic dimension, end-diastolic volume, end-systolic volume, stroke volume, cardiac output, ejection fraction, fractional shortening) after 36 weeks. Exercise training did not induce left ventricular (LV) enlargement as evidence of an absence of increase in left ventricular end-diastolic volume. The total cholesterol level and triglyceride level decreased after training. High density lipoprotein-cholesterol significantly increased and low density lipoprotein-cholesterol significantly decreased, atherogenic index (AI) significantly decreased and apolipoprotein A-I increased and apolipoprotein B decreased after training. In conclusion, although there was no significant change in left ventricular function, aerobic training showed a positive influence on body composition, maximal oxygen consumption and serum lipids.

Apolipoprotein A-I↗

PubMed2003

The effect of combined aerobic and resistance exercise training on abdominal fat in obese middle-aged women.

The purpose of this study was to investigate the effect of combined aerobic and resistance training on abdominal fat. Our participants in the study consisted of thirty obese women. They were separated into three groups: a control group (n=10), an aerobic training group (n=10) and a combined training group (n=10). The aerobic training group was composed of 60-70% HRmax (intensity), 60 minutes a day (duration) for 6 days a week (frequency). The combined training group was separated into resistance training (3 days a week, Mon, Wed, Fri) and the aerobic training (3 days a week, Tue, Thu, Sat). The levels for abdominal fat volume were measured by determining the subcutaneous fat volume (SFV), visceral fat volume (VFV), and VFV/SFV by CT (computed tomography). The VO(2max) was significantly (p<0.05) increased in both groups. The subcutaneous fat and visceral fat levels were decreased in the combined training group more than in the aerobics training group. Also, the lean body mass (LBM) was significantly increased only in the combined training group. In addition, the total cholesterol, triglyceride and LDL-C were significantly (p<.05) decreased and the HDL-C was significantly (p<.05) increased in both groups. In conclusion, our results observed that combined training decreased abdominal subcutaneous fat and visceral fat more than aerobic training only.

Abdomen↗

PubMed2002

Germline mutations of BRCA1 and BRCA2 in Korean breast and/or ovarian cancer families.

Germline mutations in the BRCA1 and BRCA2 genes are responsible for the predisposition and development of familial breast and/or ovarian cancer. Most mutations of BRCA1 and BRCA2 associated with breast and/or ovarian cancer result in truncated proteins. To investigate the presence of BRCA1 and BRCA2 germline mutations in Korean breast and/or ovarian cancer families, we screened a total of 27 cases from 21 families including two or more affected first- or second-degree relatives with breast and/or ovarian cancer. PTT, PCR-SSCP, and DHPLC analysis, followed by sequencing were used in the screening process. In nine families, we found BRCA1 and BRCA2 germline mutations that comprised four frameshift mutations and five nonsense mutations. All nine mutations led to premature termination producing shortened proteins. Among the nine mutations, three novel BRCA1 mutations (E1114X, Q1299X, 4159delGA) and two novel BRCA2 mutations (K467X, 8945delAA) were identified in this work.

BRCA1 Protein↗

PubMed2002

RET oligonucleotide microarray for the detection of RET mutations in multiple endocrine neoplasia type 2 syndromes.

Multiple endocrine neoplasia type 2 (MEN2) syndromes are inherited in an autosomal dominant fashion with high penetrance. There are three subtypes, namely, MEN2A (multiple endocrine neoplasia type 2A), MEN2B (multiple endocrine neoplasia type 2B), and familial medullary thyroid carcinoma. The variations in the RET gene play an important role in the MEN2 syndromes. In this work, we have developed a RET oligonucleotide microarray of 67 oligonucleotides to quickly detect RET mutations in MEN2 syndromes. The predominant RET mutations are missense mutations and are restricted to nine codons (codons 609, 611, 618, 620, 630, 634, 768, 804, and 918) in MEN2 syndromes. Missense mutations at codons 609, 611, 618, 620, and 634 have been identified in 98% of MEN2A families and in 85% of familial medullary thyroid carcinoma families. More than 95% of MEN2B patients also had a predominant mutation type at codon 918 (Met-->Thr). RET oligonucleotide microarray can detect RET missense mutations at these nine codons. Theoretically, a total of 55 missense mutation types can occur at eight codons (codons 609, 611, 618, 620, 630, 634, 768, and 804). RET oligonucleotide microarray is designed to detect all of these 55 missense mutation types at these eight codons and one predominant type at codon 918. Fifty-six oligonucleotides were designed for the 56 mutation types at nine codons, and 11 oligonucleotides were designed for the wild types and positive controls. We found RET mutations in all eight of the Korean MEN2A families (a total of 75 members; 27 affected members, 19 gene carriers, and 29 unaffected members) using the developed RET oligonucleotide microarray and an automatic sequencing. Because we found only five mutation types from eight MEN2A families, the international collaborations are required to see whether the RET oligonucleotide microarray may be used as a genetic diagnostic tool. Taken together, the RET oligonucleotide microarray can function as a fast and reliable genetic diagnostic device, which simplifies the process of detecting RET mutations.

Cloning, Molecular↗