Biomedical subjects

Jae-Hoon Jung

Publications and source records attributed to Jae-Hoon Jung.

7 recordsLinked to original sources

PubMed2006

MIR166/165 genes exhibit dynamic expression patterns in regulating shoot apical meristem and floral development in Arabidopsis.

The miR166/165 group and its target genes regulate diverse aspects of plant development, including apical and lateral meristem formation, leaf polarity, and vascular development. We demonstrate here that MIR166/165 genes are dynamically controlled in regulating shoot apical meristem (SAM) and floral development in parallel to the WUSCHEL (WUS)-CLAVATA (CLV) pathway. Although miR166 and miR165 cleave same target mRNAs, individual MIR166/165 genes exhibit distinct expression domains in different plant tissues. The MIR166/165 expression is also temporarily regulated. Consistent with the dynamic expression patterns, an array of alterations in SAM activities and floral architectures was observed in the miR166/165-overproducing plants. In addition, when a MIR166a-overexpressing mutant was genetically crossed with mutants defective in the WUS-CLV pathway, the resultant crosses exhibited additive phenotypic effects, suggesting that the miR166/165-mediated signal exerts its role via a distinct signaling pathway.

Arabidopsis↗

PubMed2005

Characterization of an Arabidopsis gene that mediates cytokinin signaling in shoot apical meristem development.

Cytokinins are adenine derivatives that regulate numerous plant growth and developmental processes, including apical and floral meristem development, stem growth, leaf senescence, apical dominance, and stress tolerance. However, not much is known about how cytokinin biosynthesis and metabolism is regulated. We identified a novel Arabidopsis gene, ALL, encoding an aldolase-like enzyme that regulates cytokinin signaling. An Arabidopsis mutant, all-1D, in which ALL is activated by the nearby insertion of the 35S enhancer, exhibited extreme dwarfism with rolled, dark-green leaves and reduced apical dominance, symptomatic of cytokinin-overproducing mutants. Consistent with this, ARR4 and ARR5, two representative primary cytokinin-responsive genes, were significantly induced in all-1D. Whereas SHOOT MERISTEMLESS (STM) and KNAT1, which regulate meristem development, were also greatly induced, expression of REV and PHV that regulate lateral organ polarity was inhibited. ALL encodes an aldolase-like enzyme that belongs to the HpcH/HpaI aldolase family in prokaryotes and is down-regulated by exogenous cytokinin, possibly through a negative feedback pathway. We propose that ALL is involved in cytokinin biosynthesis or metabolism and acts as a positive regulator of cytokinin signaling during shoot apical meristem development and determination of lateral organ polarity.

Aldehyde-Lyases↗

PubMed2005

Clustered localized pigmented villonodular synovitis.

The localized form of pigmented villonodular synovitis (PVNS) is a rare pathologic entity characterized by limited involvement of the synovium. In the knee joint, which is the most commonly affected joint, the disorder generally presents as a single nodular lesion, or rarely as 2 or 3 multiple nodular lesions into the joint. We report 2 cases of localized PVNS in which multiple nodules were clustered in a limited patella fat pad area. Clustered, multiple nodular lesions in a limited area suggested to us to consider a variant of localized forms.

Adult↗

PubMed2005

A white blood cell count in the normal concentration range is independently related to cardiorespiratory fitness in apparently healthy Korean men.

Despite the documented health benefits of physical activity, the mechanism whereby physical activity prevents cardiovascular disease is incompletely understood. In the present study, we investigated the relationship between white blood cell (WBC) count and cardiorespiratory fitness (V o(2)max) after adjusting for several well-known cardiovascular risk factors. Subjects who visited our health promotion center for a medical checkup and treadmill test (n=8241; age: median, 48 years; range, 16-79 years) were classified into 3 groups based on their WBC counts (group 1, 2200-5300 microL, n=2823; group 2, 5301-6500 microL, n=2709; group 3, 6501-10000 microL, n=2709). After adjusting for age, body mass index, body fat percentage, smoking history, systolic blood pressure, diastolic blood pressure, serum lipid profile, and fasting plasma glucose, V o(2)max still showed a significant association with WBC count (partial r=-0.11, P<.001). In logistic regression analyses, subjects in the highest WBC tertile showed lower V o(2)max compared with those in the lowest WBC tertile after adjusting for age and cardiovascular risk factors (odds ratio, 0.42; 95% confidence interval, 0.36-0.49 for the highest V o(2)max tertile). These results suggest that a WBC count in the normal concentration range is independently related to cardiorespiratory fitness in Korean men.

Adolescent↗

PubMed2005

microRNA-directed cleavage of ATHB15 mRNA regulates vascular development in Arabidopsis inflorescence stems.

Class III homeodomain-leucine zipper proteins regulate critical aspects of plant development, including lateral organ polarity, apical and lateral meristem formation, and vascular development. ATHB15, a member of this transcription factor family, is exclusively expressed in vascular tissues. Recently, a microRNA (miRNA) binding sequence has been identified in ATHB15 mRNA, suggesting that a molecular mechanism governed by miRNA binding may direct vascular development through ATHB15. Here, we show that miR166-mediated ATHB15 mRNA cleavage is a principal mechanism for the regulation of vascular development. In a gain-of-function MIR166a mutant, the decreased transcript level of ATHB15 was accompanied by an altered vascular system with expanded xylem tissue and interfascicular region, indicative of accelerated vascular cell differentiation from cambial/procambial cells. A similar phenotype was observed in Arabidopsis plants with reduced ATHB15 expression but reversed in transgenic plants overexpressing an miR166-resistant ATHB15. ATHB15 mRNA cleavage occurred in standard wheat germ extracts and in Arabidopsis and was mediated by miR166 in Nicotiana benthamiana cells. miR166-assisted ATHB15 repression is likely to be a conserved mechanism that regulates vascular development in all vascular plants.

Arabidopsis↗

PubMed2005

Fasting plasma glucose cutoff value for the prediction of future diabetes development: a study of middle-aged Koreans in a health promotion center.

We determined optimal fasting plasma glucose (FPG) cutoff values predictive of future diabetes development in a group of middle-aged Koreans who visited a health promotion center. The medical records of 2,964 subjects, who attended the Health Promotion Center in 1998 and 2003, were examined. Subjects were classified into four groups according to their baseline FPG values (Group 1:FPG <5.0 mM/L; Group 2: 5.0< or =FPG <5.6 mM/L; Group 3: 5.6< or =FPG <6.1 mM/L; Group 4: 6.1< or =FPG <7.0 mM/L). No significant difference was observed between Group 1 and Group 2 in terms of diabetes incidence. However, incidence in Group 3 was significantly higher than that in Group 1 [hazards ratio 4.88 (1.65-14.41), p=0.004] and the hazards ratio in Group 4 for diabetes was 36.91 (13.11-103.61), p<0.001, versus Group 1. Receiver operator characteristics curve analysis showed that an FPG of 5.97 mM/L represents the lower limit and gives the best combination of sensitivity and specificity. Our data shows that the risk of future diabetes development started to increase below an FPG of 6.1 mM/L and suggests the importance of efforts to modify diabetes development risk factors at lower impaired fasting glucose levels.

Adult↗

PubMed2004

Lipoma arborescens of the knee.

Lipoma arborescens are rare lesions, typically located in the knee. They have a predilection for the suprapatellar pouch in the knee joint, but can also occur in any area of the knee joint. Magnetic resonance imaging of lipoma arborescens often reveals subchondral bone cyst and/or bone erosions, and there may appear to be a correlation between lipoma arborescens and osteoarthritis. We describe a case of histologically proven lipoma arborescens in the suprapatellar pouch and infrapatellar area of the knee with no damage to the posterior compartment and bone erosion in the proximal tibia without osteoarthritis.

Adipose Tissue↗