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1.
J Am Coll Health ; 71(1): 318-324, 2023 01.
Article in English | MEDLINE | ID: mdl-33759715

ABSTRACT

Objective: To identify and evaluate salient beliefs about sport participation among South Korean university students. Participants: Total 234 undergraduate students were recruited in the main study from one university located in Seoul, South Korea. Methods: An elicitation study was conducted to identify salient beliefs about sport participation. Structural equation modeling was used to examine the effects of the elicited salient beliefs on intention to participate in sports and sport participation behavior. Results: Four of ten salient beliefs identified from the elicitation study (i.e., "builds social relationship," "makes me tired," "takes too much time," and "friends") indirectly affected sport participation behavior through intention. Conclusion: The four salient beliefs may play a critical role in developing effective interventions or policies for promoting sport participation.


Subject(s)
Sports , Students , Humans , Universities , Intention , Republic of Korea
2.
Prev Med Rep ; 29: 101919, 2022 Oct.
Article in English | MEDLINE | ID: mdl-35911572

ABSTRACT

NUTRI-SCORE is a front-of-pack labeling method that relies of the computation of a nutrient profiling system by reconstructing and presenting nutritional information about food items. In particular, different scores are assigned to harmful (energy, sugars, saturated fatty acids, and salt) and beneficial (proteins, fibers, fruits, vegetables, nuts, rapeseed oil, walnut oil, and olive oil) nutrients. These scores are combined to assign a final five different 'NUTRI-SCORE' to the food item from healthiest A to most harmful E. This study examined the effect of NUTRI-SCORE labeling on the sales of food items in stores at sports and non-sports facilities. The NUTRI-SCORE label was attached to the price tag of food items sold in two food stores of Seoul National University (sports-related and non-sports-related facilities) for 5 weeks. Baseline sales data from the previous 2 years were obtained from the food stores. The predicted data based on baseline sales were compared to the new sales data during the study period. The data trends were analyzed using interrupted time-series analysis, which showed significant group differences. In the sports-facility store, sales were higher for relatively healthy food items than for less-healthy food items. Conversely, mixed results were observed for sales in the non-sports-facility store. First, sales of Grade A foods decreased but sales of Grade B and Grade E foods increased. Therefore, the results imply that NUTRI-SCORE labeling positively affected sales of healthy foods only in the sports facilities because few people in non-sports facilities sought to purchase healthy foods. These results will help to improve the nutrition-related behavior of food consumers and point to the differences in cognitive consumption patterns between consumers at sports and non-sports facilities.

3.
Am J Mens Health ; 16(1): 15579883221076897, 2022.
Article in English | MEDLINE | ID: mdl-35184574

ABSTRACT

The main aim of the present study is to evaluate reach, dose, fidelity, and outcomes of the interventions for promoting voluntary exercise training among South Korean firefighters. Four interventions for promoting voluntary exercise training among firefighters (i.e., virtual reality exercise system intervention, poster intervention, monitor intervention, and wearable health device intervention) were performed in a fire station located in Seoul, South Korea. To evaluate reach and dose received related to each intervention, participants were asked to answer several simple questions. Three process evaluators completed a 20-item survey to share their impressions related to the quality of intervention delivery. Paired t test was used to examine mean changes in primary (i.e., mean minutes of exercise training per week) and secondary outcomes (i.e., beliefs and intention) between pre- and postinterventions. More than 60% of participants experienced monitor and wearable health device interventions. Process evaluators tend not to agree with a statement saying that the number of the virtual reality exercise equipment was appropriate. Among firefighters who participated in exercise training less than 150 min per week at 1-month follow-up, mean minutes of exercise training per week increased by 67.95 min after interventions. Future studies need to examine whether the monitor and wearable health device interventions effectively increase exercise training participation among firefighters in other fire stations located in Seoul, South Korea.


Subject(s)
Firefighters , Exercise , Humans , Intention , Outcome Assessment, Health Care , Republic of Korea
4.
Biologicals ; 71: 20-30, 2021 Jun.
Article in English | MEDLINE | ID: mdl-33994086

ABSTRACT

The rabbit pyrogen test (RPT) is a safety test conducted as a part of mandatory requirements of regulatory agencies. RPT is currently performed for routine quality control (QC) by manufacturers and for national lot release of biological products, such as plasma-derived products. However, RPT involves the use of many rabbits, counter to the international efforts to minimize the use of animals in research. Furthermore, pyrogen amount cannot be discerned from the test results and the results may be considerably affected by various factors. Therefore, a need exists for substituting RPT with in vitro assays. As a viable alternative to RPT, we here established a rabbit monocyte activation test (RMAT) based on the human MAT in the European Pharmacopoeia. RMAT uses rabbit peripheral blood mononuclear cells as the source of monocytes instead of live animals. The test detected endotoxin, lipoteichoic acid, peptidoglycan, and zymosan with high sensitivity, showing high correlation with the in vivo RPT results. The results of RMAT and RPT testing of non-pyrogenic plasma-derived products were also consistent. Furthermore, RMAT showed satisfactory recovery rates in an interference test with product samples and spiked-in pyrogens. We conclude that RMAT could replace the existing RPT for routine QC.


Subject(s)
Animal Testing Alternatives , Biological Assay , Monocytes , Pyrogens , Animals , Endotoxins , Leukocytes, Mononuclear , Lipopolysaccharides , Peptidoglycan , Pyrogens/analysis , Quality Control , Rabbits , Teichoic Acids , Zymosan
5.
Article in English | MEDLINE | ID: mdl-33804403

ABSTRACT

Previous studies have identified that a behavior can occur through the strongest predictor intention, but there is a gap between intention and behavior. Dopamine receptor D2 (DRD2) is known to account for a variance in sporting behaviors in human and animal subjects. However, the relationship between DRD2 and sport participation has been poorly studied, and the limited available reports are inconsistent. The present study was performed to examine the impact of DRD2 on sport participation among Korean university students based on the integrated behavioral model (IBM). Data were collected from enrolled university students in Seoul (N = 45). Participants answered survey questions first, and then they gave investigators their hair to provide DNA information (i.e., the A1 allele of DRD2). DRD2 had a significant effect on sport participation, but only in male students. Male students who carried the A1 allele of DRD2 significantly participated in 105.10 min more sporting activities than male students who did not. Moreover, the effect of intention on sport participation was significantly decreased when considering DRD2. Despite the small sample size, the results of this study could be a preliminary case for a larger study and indicate the direction of future research. Our results suggest that DRD2 may have played an important role as the "actual skill" shown in the IBM.


Subject(s)
Intention , Sports , Alleles , Humans , Male , Receptors, Dopamine D2/genetics , Seoul
6.
Toxicol Res ; 34(3): 191-197, 2018 Jul.
Article in English | MEDLINE | ID: mdl-30057693

ABSTRACT

In 2015, a candidate for the second national reference standard (NRS) of Gloydius snake venom was produced to replace the first NRS of Gloydius snake venom. In the present study, the potencies of the candidate were determined by a collaborative study, and the qualification of the candidate was estimated. The potencies of the candidate were determined by measuring the murine lethal titers and lapine hemorrhagic titers of venom against the regional working reference standard (RWRS) for antivenom using the methods described in the previous report for the first NRS of Gloydius snake venom. Three Korean facilities contributed data from a total of 30 independent assays. Subsequently, two foreign national control research laboratories contributed to this collaborative study. The results were calculated using the Reed-Muench method for lethality and determined using a mixed-effects model for hemorrhage. The general common potencies of the lethal and hemorrhagic titers were obtained from the results of the 30 tests performed at three Korean facilities. The results are expressed in micrograms for 1 test dose (TD) with a 95% confidence interval as follows: a lethal titer of 90.13 µg/TD (95% confidence interval = 87.39~92.86 µg) and a hemorrhagic titer of 10.80 µg/TD (95% confidence interval = 10.46~11.14 µg). In addition, the candidate preparation showed good quality evaluation according to the results of the quality estimation of the candidate and is judged to be suitable to serve as the Korean NRS for snake venom. In conclusion, the second NRS of Gloydius snake venom was established in this study and will be used for national quality control, including a national lot release test of Korean antivenom products.

7.
Biomol Ther (Seoul) ; 25(3): 266-271, 2017 May 01.
Article in English | MEDLINE | ID: mdl-27871157

ABSTRACT

Synthetic cannabinoids are one of most abused new psychoactive substances. The recreational use of abused drug has aroused serious concerns about the consequences of these drugs on infection. However, the effects of synthetic cannabinoid on resistance to tetanus toxin are not fully understood yet. In the present study, we aimed to determine if the administration of synthetic cannabinoids increase the susceptibility to tetanus toxin-induced motor behavioral deficit and functional changes in cerebellar neurons in mice. Furthermore, we measured T lymphocytes marker levels, such as CD8 and CD4 which against tetanus toxin. JWH-210 administration decreased expression levels of T cell activators including cluster of differentiation (CD) 3ε, CD3γ, CD74p31, and CD74p41. In addition, we demonstrated that JWH-210 induced motor impairment and decrement of vesicle-associated membrane proteins 2 levels in the cerebellum of mice treated with tetanus toxin. Furthermore, cerebellar glutamatergic neuronal homeostasis was hampered by JWH-210 administration, as evidenced by increased glutamate concentration levels in the cerebellum. These results suggest that JWH-210 may increase the vulnerability to tetanus toxin via the regulation of immune function.

8.
Toxicol Res ; 32(4): 269-274, 2016 Oct.
Article in English | MEDLINE | ID: mdl-27818728

ABSTRACT

The potency of influenza vaccine is determined based on its hemagglutinin (HA) content. In general, single radial immunodiffusion (SRID) assay has been utilized as the standard method to measure HA content. However, preparation of reagents for SRID such as antigen and antibody takes approximately 2~3 months, which causes delays in the development of influenza vaccine. Therefore, quantification of HA content by other alternative methods is required. In this study, we measured HA contents of H1N1 antigen and H1N1 influenza vaccine by reverse phase-high performance liquid chromatography (RP-HPLC) methods. The presence of HA1 and HA2 was investigated by silver staining and Western blot assay. In addition, accuracy and repeatability of HA measurement by RP-HPLC were evaluated. Comparison of HA concentration by SRID and RP-HPLC revealed a precise correlation between the two methods. Our results suggest that RP-HPLC assay can replace SRID in the event of a pandemic flu outbreak for rapid vaccine development.

9.
J Korean Med Sci ; 31(3): 360-70, 2016 Mar.
Article in English | MEDLINE | ID: mdl-26955235

ABSTRACT

Cancer stem cells (CSCs) have tumor initiation, self-renewal, metastasis and chemo-resistance properties in various tumors including colorectal cancer. Targeting of CSCs may be essential to prevent relapse of tumors after chemotherapy. Phosphatidylinositol-3-kinase (PI3K) and mammalian target of rapamycin (mTOR) signals are central regulators of cell growth, proliferation, differentiation, and apoptosis. These pathways are related to colorectal tumorigenesis. This study focused on PI3K and mTOR pathways by inhibition which initiate differentiation of SW620 derived CSCs and investigated its effect on tumor progression. By using rapamycin, LY294002, and NVP-BEZ235, respectively, PI3K and mTOR signals were blocked independently or dually in colorectal CSCs. Colorectal CSCs gained their differentiation property and lost their stemness properties most significantly in dual-blocked CSCs. After treated with anti-cancer drug (paclitaxel) on the differentiated CSCs cell viability, self-renewal ability and differentiation status were analyzed. As a result dual-blocking group has most enhanced sensitivity for anti-cancer drug. Xenograft tumorigenesis assay by using immunodeficiency mice also shows that dual-inhibited group more effectively increased drug sensitivity and suppressed tumor growth compared to single-inhibited groups. Therefore it could have potent anti-cancer effects that dual-blocking of PI3K and mTOR induces differentiation and improves chemotherapeutic effects on SW620 human colorectal CSCs.


Subject(s)
Cell Differentiation/drug effects , Phosphoinositide-3 Kinase Inhibitors , Signal Transduction/drug effects , TOR Serine-Threonine Kinases/antagonists & inhibitors , AC133 Antigen/genetics , AC133 Antigen/metabolism , Animals , Antineoplastic Agents/pharmacology , Antineoplastic Agents/therapeutic use , Cell Line, Tumor , Cell Survival/drug effects , Chromones/pharmacology , Chromones/therapeutic use , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/metabolism , Colorectal Neoplasms/pathology , Humans , Imidazoles/pharmacology , Imidazoles/therapeutic use , Male , Mice , Mice, Inbred BALB C , Mice, Nude , Morpholines/pharmacology , Morpholines/therapeutic use , Neoplastic Stem Cells/cytology , Neoplastic Stem Cells/drug effects , Neoplastic Stem Cells/metabolism , Paclitaxel/pharmacology , Paclitaxel/therapeutic use , Phosphatidylinositol 3-Kinases/metabolism , Quinolines/pharmacology , Quinolines/therapeutic use , SOXB1 Transcription Factors/genetics , SOXB1 Transcription Factors/metabolism , Sirolimus/pharmacology , Sirolimus/therapeutic use , TOR Serine-Threonine Kinases/metabolism , Xenograft Model Antitumor Assays
10.
J Foot Ankle Surg ; 54(6): 1053-6, 2015.
Article in English | MEDLINE | ID: mdl-26232175

ABSTRACT

Haglund syndrome is characterized by chronic posterior heel pain associated with a posterosuperior calcaneal prominence. We assessed the clinical and radiologic outcomes after operative treatment of Haglund syndrome using the central tendon-splitting approach. Fifteen feet in 15 patients were investigated retrospectively after surgery. Of the 15 patients, 14 were males (93.3%) and 1 was female (6.7%). Their mean age was 33.1 ± 8.2 (range 20 to 50) years. The mean follow-up duration was 3.5 ± 1.5 years (range 24 to 90 months). The American Orthopaedic Foot and Ankle Society ankle-hindfoot Scale and Victorian Institute of Sport Assessment-Achilles scores were investigated to assess the clinical outcomes. Patient satisfaction was assessed at the latest follow-up visit. The lateral talo-first metatarsal angle, calcaneal pitch angle, Fowler-Philip angle, and parallel pitch line were measured to assess the foot shape and radiographic outcomes. Clinically, the mean American Orthopaedic Foot and Ankle Society ankle-hindfoot scale score increased from 62.1 ± 7.5 preoperatively to 92.5 ± 3.5 at the latest follow-up visit. The mean Victorian Institute of Sport Assessment-Achilles score increased from 53.2 ± 7.4 to 89.6 ± 3.4. All patients were satisfied with the operative results. Radiographically, all patients had cavus feet with an increased lateral talo-first metatarsal angle (mean +5.9° ± 5.0°) and calcaneal pitch angle (mean 26.0° ± 3.8°). The mean Fowler-Philip angle decreased from 58.9° ± 15.0° to 32.5° ± 7.2° postoperatively, and the positive parallel pitch line had changed to a negative value in all cases. Operative treatment with the central tendon-splitting approach appears to be safe and satisfactory for intractable Haglund syndrome.


Subject(s)
Achilles Tendon/surgery , Calcaneus/surgery , Foot Deformities, Acquired/surgery , Heel Spur/surgery , Pain/etiology , Tendinopathy/surgery , Adult , Female , Heel Spur/complications , Humans , Male , Middle Aged , Retrospective Studies , Tendinopathy/complications , Young Adult
11.
Biosci Biotechnol Biochem ; 79(9): 1438-46, 2015.
Article in English | MEDLINE | ID: mdl-25964982

ABSTRACT

We investigated the role of profilin 2 in the stemness, migration, and invasion of HT29 cancer stem cells (CSCs). Increased and decreased levels of profilin 2 significantly enhanced and suppressed the self-renewal, migration, and invasion ability of HT29 CSCs, respectively. Moreover, profilin 2 directly regulated the expression of stemness markers (CD133, SOX2, and ß-catenin) and epithelial mesenchymal transition (EMT) markers (E-cadherin and snail). CD133 and ß-catenin were up-regulated by overexpression of profilin 2 and down-regulated by depletion of profilin 2. SOX2 was decreased by profilin 2 depletion. E-cadherin was not influenced by profilin 2- overexpression but increased by profilin 2- knockdown. The expression of snail was suppressed by profilin 2- knockdown. We speculated that stemness and the EMT are closely linked through profilin 2-related pathways. Therefore, this study indicates that profilin 2 affects the metastatic potential and stemness of colorectal CSCs by regulating EMT- and stemness-related proteins.


Subject(s)
Colorectal Neoplasms/genetics , Neoplasm Proteins/biosynthesis , Neoplastic Stem Cells , Profilins/genetics , Cell Line, Tumor , Cell Movement/genetics , Colorectal Neoplasms/pathology , Epithelial-Mesenchymal Transition/genetics , Gene Expression Regulation, Neoplastic , Gene Knockdown Techniques , HT29 Cells , Humans , Neoplasm Invasiveness/genetics , Profilins/biosynthesis , Wnt Signaling Pathway/genetics , beta Catenin/biosynthesis
12.
Clin Orthop Surg ; 6(3): 361-4, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25177465

ABSTRACT

During imaging studies or surgical procedures, anomalous forearm and wrist muscles are occasionally encountered. Among them, the flexor carpi radialis brevis is very rare. Because the trend is growing toward treating distal radius fractures with volar plating, the flexor carpi radialis brevis is worth knowing. Here, we report two cases with a review of the literature.


Subject(s)
Forearm/abnormalities , Muscle, Skeletal/abnormalities , Wrist/abnormalities , Female , Fractures, Comminuted/surgery , Humans , Middle Aged , Radius Fractures/surgery , Ulna Fractures/surgery
13.
J Microbiol ; 52(5): 435-40, 2014 May.
Article in English | MEDLINE | ID: mdl-24610332

ABSTRACT

We previously reported the development of a neutralization assay system for evaluating Japanese Encephalitis Virus (JEV) neutralizing antibody (NAb) using pseudotyped-JEV (JEV-PV). JEV-PV-based neutralization assay offers several advantages compared with the current standard plaque-reduction neutralization test (PRNT), including simplicity, safety, and speed. To evaluate the suitability of the JEV-PV assay as new replacement neutralization assay, we compared its repeatability, reproducibility, specificity, and correlated its results with those obtained using the PRNT. These analyses showed a close correlation between the results obtained with the JEV-PV assay and the PRNT, using the 50% plaque reduction method as a standard for measuring NAb titers to JEV. The validation results met all analytical acceptance criteria. These results suggest that the JEV-PV assay could serve as a safe and simple method for measuring NAb titer against JEV and could be used as an alternative approach for assaying the potency of JEV neutralization.


Subject(s)
Antibodies, Neutralizing/analysis , Antigens, Viral , Encephalitis Viruses, Japanese/immunology , Neutralization Tests/methods , Viral Plaque Assay/methods , Encephalitis Viruses, Japanese/genetics , Reproducibility of Results , Sensitivity and Specificity
14.
Vaccine ; 31(41): 4466-9, 2013 Sep 23.
Article in English | MEDLINE | ID: mdl-23933367

ABSTRACT

Typhoid fever is a gastrointestinal disease transmitted through the ingestion of contaminated water or food. The bacterium, Salmonella enterica subspecies enterica serovar Typhi is an important cause of illness and death in many poor countries where access to safe water and basic sanitation is limited. Humans are the only natural host and reservoir of S. Typhi. Typhoid fever causes around 21 million cases and at least 200,000 deaths per year. Currently, several groups are developing typhoid conjugate vaccines that are expected to be safe and effective in infancy or early childhood. The World Health Organization convened a meeting, in collaboration with the Korea Food and Drug Administration, with experts group in September 2012 to develop guidelines for regulatory evaluation of the quality, safety and efficacy of typhoid conjugate vaccines. This report summarizes collective views on scientific and technical issues that need to be considered in the guidelines.


Subject(s)
Drug Approval/methods , Polysaccharides, Bacterial/adverse effects , Polysaccharides, Bacterial/immunology , Typhoid Fever/prevention & control , Typhoid-Paratyphoid Vaccines/adverse effects , Typhoid-Paratyphoid Vaccines/immunology , Vaccination/methods , Global Health , Guidelines as Topic , Humans , Polysaccharides, Bacterial/administration & dosage , Typhoid-Paratyphoid Vaccines/administration & dosage , Vaccination/adverse effects , World Health Organization
15.
Diagn Interv Radiol ; 19(1): 76-80, 2013.
Article in English | MEDLINE | ID: mdl-23019056

ABSTRACT

A 61-year-old male patient with atherosclerotic critical limb ischemia in the left leg underwent stent insertion into the left superficial femoral artery. Stenting procedures improved Rutherford grade from III-5 to II-4. Granulocyte colony-stimulating factor stimulated the production of white blood cells over four-fold and mononuclear cells (MNCs) 1.5-fold in the whole blood. Transplantation of 7.9x10(9) autologous MNCs into the left femoral artery rapidly decreased the leg pain intensity, with further improvement of Rutherford grades from II-4 to 0-0 without any side effects. In the four-year follow-up, significant improvement was found in terms of ankle brachial index, from nondetectable to 0.67, and peak systolic velocity, from 14.8 to 36.1 cm/s. Limb salvage and decreased resting pain were the notable outcomes of the treatment.


Subject(s)
Ischemia/surgery , Leg/blood supply , Neovascularization, Physiologic , Peripheral Blood Stem Cell Transplantation/methods , Stents , Transplantation, Autologous/methods , Atherosclerosis/complications , Constriction, Pathologic/etiology , Constriction, Pathologic/surgery , Critical Illness , Follow-Up Studies , Humans , Ischemia/etiology , Limb Salvage/methods , Male , Middle Aged , Treatment Outcome
16.
Knee Surg Relat Res ; 24(1): 34-9, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22570850

ABSTRACT

PURPOSE: We aimed to compare cross-pin fixation and Endobutton femoral fixation for hamstring anterior cruciate ligament (ACL) reconstruction with respect to clinical and radiographic results, including tunnel widening and the progression of knee osteoarthritis (OA). MATERIALS AND METHODS: Between August 2002 and August 2005, 126 autogenous hamstring ACL reconstructions were performed using either cross pins or Endobutton for femoral fixation. Fifty-six of 75 patients in the cross-pin group and 35 of 51 patients in the Endobutton group were followed up for a minimum of 4 years. We compared the clinical and radiological results between the groups using the International Knee Documentation Committee (IKDC) evaluation form, the KT-2000 arthrometer side to side difference, the amount of tunnel widening and the advancement of OA on radiographs. RESULTS: There were no significant differences in the IKDC grades between the groups at the 4 year follow-up. There was no significant difference in the side to side difference according to KT-2000 arthrometer testing. Also, there were no significant differences in terms of tunnel widening or advancement of OA on radiographs. CONCLUSIONS: Endobutton femoral fixation showed good results that were comparable to those of cross pins fixation in hamstring ACL reconstruction.

17.
J Korean Med Sci ; 25(2): 211-9, 2010 Feb.
Article in English | MEDLINE | ID: mdl-20119572

ABSTRACT

This study aimed to characterize and MRI track the mesenchymal stem cells labeled with chitosan-coated superparamagnetic iron oxide (Chitosan-SPIO). Chitosan-SPIO was synthesized from a mixture of FeCl(2) and FeCl(3). The human bone marrow derived mesenchymal stem cells (hBM-MSC) were labeled with 50 microg Fe/mL chitosan-SPIO and Resovist. The labeling efficiency was assessed by iron content, Prussian blue staining, electron microscopy and in vitro MR imaging. The labeled cells were also analyzed for cytotoxicity, phenotype and differentiation potential. Electron microscopic observations and Prussian blue staining revealed 100% of cells were labeled with iron particles. MR imaging was able to detect the labeled MSC successfully. Chitosan-SPIO did not show any cytotoxicity up to 200 microg Fe/mL concentration. The labeled stem cells did not exhibit any significant alterations in the surface markers expression or adipo/osteo/chondrogenic differentiation potential when compared to unlabeled control cells. After contralateral injection into rabbit ischemic brain, the iron labeled stem cells were tracked by periodical in vivo MR images. The migration of cells was also confirmed by histological studies. The novel chitosan-SPIO enables to label and track MSC for in vivo MRI without cellular alteration.


Subject(s)
Chitosan/chemistry , Coordination Complexes/chemistry , Ferric Compounds/chemistry , Mesenchymal Stem Cells/chemistry , Metal Nanoparticles/chemistry , Animals , Brain Ischemia/chemically induced , Brain Ischemia/pathology , Brain Ischemia/therapy , Cell Differentiation , Coordination Complexes/toxicity , Humans , Magnetic Resonance Imaging , Magnetics , Mesenchymal Stem Cell Transplantation , Mesenchymal Stem Cells/cytology , Phenotype , Rabbits
18.
J Biol Chem ; 284(35): 23426-35, 2009 Aug 28.
Article in English | MEDLINE | ID: mdl-19567870

ABSTRACT

Dihydropterin deaminase, which catalyzes the conversion of 7,8-dihydropterin to 7,8-dihydrolumazine, was purified 5850-fold to apparent homogeneity from Drosophila melanogaster. Its molecular mass was estimated to be 48 kDa by gel filtration and SDS-PAGE, indicating that it is a monomer under native conditions. The pI value, temperature, and optimal pH of the enzyme were 5.5, 40 degrees C, and 7.5, respectively. Interestingly the enzyme had much higher activity for guanine than for 7,8-dihydropterin. The specificity constant (k(cat)/K(m)) for guanine (8.6 x 10(6) m(-1).s(-1)) was 860-fold higher than that for 7,8-dihydropterin (1.0 x 10(4) m(-1).s(-1)). The structural gene of the enzyme was identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry analysis as CG18143, located at region 82A1 on chromosome 3R. The cloned and expressed CG18143 exhibited both 7,8-dihydropterin and guanine deaminase activities. Flies with mutations in CG18143, SUPor-P/Df(3R)A321R1 transheterozygotes, had severely decreased activities in both deaminases compared with the wild type. Among several red eye pigments, the level of aurodrosopterin was specifically decreased in the mutant, and the amount of xanthine and uric acid also decreased considerably to 76 and 59% of the amounts in the wild type, respectively. In conclusion, dihydropterin deaminase encoded by CG18143 plays a role in the biosynthesis of aurodrosopterin by providing one of its precursors, 7,8-dihydrolumazine, from 7,8-dihydropterin. Dihydropterin deaminase also functions as guanine deaminase, an important enzyme for purine metabolism.


Subject(s)
Drosophila Proteins/metabolism , Drosophila melanogaster/enzymology , Guanine Deaminase/metabolism , Pigments, Biological/biosynthesis , Pterins/metabolism , Amino Acid Sequence , Animals , Drosophila Proteins/chemistry , Drosophila Proteins/genetics , Drosophila Proteins/isolation & purification , Drosophila melanogaster/chemistry , Drosophila melanogaster/genetics , Electrophoresis, Polyacrylamide Gel , Eye Color , Female , Guanine Deaminase/chemistry , Guanine Deaminase/genetics , Guanine Deaminase/isolation & purification , Kinetics , Male , Molecular Sequence Data , Sequence Alignment , Substrate Specificity
19.
Contrast Media Mol Imaging ; 4(3): 118-26, 2009.
Article in English | MEDLINE | ID: mdl-19308999

ABSTRACT

Magnetic resonance imaging of cells labeled with superparamagnetic iron oxide (SPIO) could be a valuable tool for tracking transplanted cells in living organisms. Human bone marrow-derived mesenchymal stem cells (hBMMSC) were labeled with a novel polyvinyl pyrrolidone (PVP)-coated SPIO. Prussian blue staining and electron microscopy revealed that almost all of the cells were efficiently labeled with PVP-SPIO nanoparticles. There were no signs of cytotoxicity, even at concentrations of up to 1600 microg Fe/ml of the nanoparticles, and the labeled cells were successfully visualized by in vitro cellular MRI. In addition, there was no significant alteration of the phenotype or the adipo/osteo/chondrogenic differentiation potential of the cells. This was in contrast to Feridex IV labeling that led to the inhibition of hBMMSC chondrogenesis. Following intramuscular injection in a rabbit hind limb ischemia model, the intercellular migration of the labeled cells toward the ablated site was clearly tracked through in vivo MRI. The localization of the transplanted cells observed by MRI correlated well with postmortem histological studies. These results demonstrate that the novel PVP-SPIO nanoparticles appear to be efficient MR contrast agents and may enable non-invasive in vivo tracking of stem cells in experimental and clinical settings during cell therapy.


Subject(s)
Ferric Compounds/metabolism , Magnetics , Mesenchymal Stem Cells/cytology , Mesenchymal Stem Cells/metabolism , Povidone/metabolism , Staining and Labeling , Animals , Biomarkers , Cell Death , Cell Differentiation , Cell Survival , Humans , Magnetic Resonance Imaging , Mesenchymal Stem Cells/ultrastructure , Phantoms, Imaging , Phenotype , Rabbits
20.
Biochem J ; 398(3): 451-60, 2006 Sep 15.
Article in English | MEDLINE | ID: mdl-16712527

ABSTRACT

The eye colour mutant sepia (se1) is defective in PDA {6-acetyl-2-amino-3,7,8,9-tetrahydro-4H-pyrimido[4,5-b]-[1,4]diazepin-4-one or pyrimidodiazepine} synthase involved in the conversion of 6-PTP (2-amino-4-oxo-6-pyruvoyl-5,6,7,8-tetrahydropteridine; also known as 6-pyruvoyltetrahydropterin) into PDA, a key intermediate in drosopterin biosynthesis. However, the identity of the gene encoding this enzyme, as well as its molecular properties, have not yet been established. Here, we identify and characterize the gene encoding PDA synthase and show that it is the structural gene for sepia. Based on previously reported information [Wiederrecht, Paton and Brown (1984) J. Biol. Chem. 259, 2195-2200; Wiederrecht and Brown (1984) J. Biol. Chem. 259, 14121-14127; Andres (1945) Drosoph. Inf. Serv. 19, 45; Ingham, Pinchin, Howard and Ish-Horowicz (1985) Genetics 111, 463-486; Howard, Ingham and Rushlow (1988) Genes Dev. 2, 1037-1046], we isolated five candidate genes predicted to encode GSTs (glutathione S-transferases) from the presumed sepia locus (region 66D5 on chromosome 3L). All cloned and expressed candidates exhibited relatively high thiol transferase and dehydroascorbate reductase activities and low activity towards 1-chloro-2,4-dinitrobenzene, characteristic of Omega class GSTs, whereas only CG6781 catalysed the synthesis of PDA in vitro. The molecular mass of recombinant CG6781 was estimated to be 28 kDa by SDS/PAGE and 56 kDa by gel filtration, indicating that it is a homodimer under native conditions. Sequencing of the genomic region spanning CG6781 revealed that the se1 allele has a frameshift mutation from 'AAGAA' to 'GTG' at nt 190-194, and that this generates a premature stop codon. Expression of the CG6781 open reading frame in an se1 background rescued the eye colour defect as well as PDA synthase activity and drosopterins content. The extent of rescue was dependent on the dosage of transgenic CG6781. In conclusion, we have discovered a new catalytic activity for an Omega class GST and that CG6781 is the structural gene for sepia which encodes PDA synthase.


Subject(s)
Glutathione Transferase/classification , Ketone Oxidoreductases/genetics , Ketone Oxidoreductases/metabolism , Amino Acid Sequence , Animals , Animals, Genetically Modified , Cloning, Molecular , Drosophila melanogaster/genetics , Gene Expression Regulation, Enzymologic , Glutathione Transferase/genetics , Glutathione Transferase/metabolism , Molecular Sequence Data , Molecular Structure , Mutation , Pteridines/chemistry , Pteridines/metabolism
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