26
|
Park HM, Lee WM. Helmholtz-Smoluchowski velocity for viscoelastic electroosmotic flows. J Colloid Interface Sci 2007; 317:631-6. [PMID: 17935728 DOI: 10.1016/j.jcis.2007.09.027] [Citation(s) in RCA: 72] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2007] [Revised: 09/03/2007] [Accepted: 09/13/2007] [Indexed: 10/22/2022]
Abstract
Many biofluids such as blood and DNA solutions are viscoelastic and exhibit extraordinary flow behaviors, not existing in Newtonian fluids. Adopting appropriate constitutive equations these exotic flow behaviors can be modeled and predicted reasonably using various numerical methods. However, the governing equations for viscoelastic flows are not easily solvable, especially for electroosmotic flows where the streamwise velocity varies rapidly from zero at the wall to a nearly uniform velocity at the outside of the very thin electric double layer. In the present investigation, we have devised a simple method to find the volumetric flow rate of viscoelastic electroosmotic flows through microchannels. It is based on the concept of the Helmholtz-Smoluchowski velocity which is widely adopted in the electroosmotic flows of Newtonian fluids. It is shown that the Helmholtz-Smoluchowski velocity for viscoelastic fluids can be found by solving a simple cubic algebraic equation. The volumetric flow rate obtained using this Helmholtz-Smoluchowski velocity is found to be almost the same as that obtained by solving the governing partial differential equations for various viscoelastic fluids.
Collapse
|
27
|
Lee BS, Kang BM, Yoon BK, Choi H, Park HM, Kim JG. Efficacy and tolerability of estradiol 1mg and drospirenone 2mg in postmenopausal korean women: A double-blind, randomized, placebo-controlled, multicenter study. Maturitas 2007; 57:361-9. [PMID: 17467203 DOI: 10.1016/j.maturitas.2007.03.004] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2006] [Revised: 03/07/2007] [Accepted: 03/14/2007] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The aim of this study was to demonstrate that the therapeutic efficacy of an estradiol 1mg/drospirenone 2mg (E2/DRSP) preparation is superior to a placebo in postmenopausal Korean women with hot flushes and other climacteric symptoms, and to demonstrate that this treatment is both safe and tolerable. METHODS This was a double-blind, randomized, placebo-controlled, multicenter study over four 28-day treatment cycles. A total of 158 subjects were screened and 90 women were randomized into two treatment groups (E2/DRSP group, n=45; placebo group, n=45). The primary efficacy parameter was the individual relative change of hot flushes. The secondary efficacy parameters such as other climacteric, urogenital symptoms and vaginal bleeding patterns were also evaluated, and the occurrence of any adverse events was noted. In addition, physical, gynecological examinations and laboratory analyses were performed at the beginning and end of the study. RESULTS The mean number of hot flushes per week during treatment weeks 3-16 decreased by 48.1% during treatment with placebo, and by 84.4% during treatment with E2/DRSP (p<0.001). The E2/DRSP combination also reduced the incidence and intensity of menopausal symptoms in postmenopausal women. Most of adverse events was mild or moderate degree of intensity. None of the parameters measured in the study, including laboratory analyses, physical and gynecological examinations, vital signs, and weight, led to any concerns of safety. CONCLUSIONS The E2 1mg/DRSP 2mg combination tested in the study was efficacious and safe in the treatment of hot flushes and other climacteric symptoms in postmenopausal Korean women.
Collapse
|
28
|
Park HM, Hong SM, Lee JS. Estimation of zeta potential of electroosmotic flow in a microchannel using a reduced-order model. Biomed Microdevices 2007; 9:751-60. [PMID: 17530411 DOI: 10.1007/s10544-007-9086-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
A reduced-order model is derived for electroosmotic flow in a microchannel of nonuniform cross section using the Karhunen-Loève Galerkin (KLG) procedure. The resulting reduced-order model is shown to predict electroosmotic flows accurately with minimal consumption of computer time for a wide range of zeta potential zeta and dielectric constant epsilon. Using the reduced-order model, a practical method is devised to estimate zeta from the velocity measurements of the electroosmotic flow in the microchannel. The proposed method is found to estimate zeta with reasonable accuracy even with noisy velocity measurements.
Collapse
|
29
|
Park HM, Kim TW. Simultaneous estimation of zeta potential and slip coefficient in hydrophobic microchannels. Anal Chim Acta 2007; 593:171-7. [PMID: 17543604 DOI: 10.1016/j.aca.2007.04.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2007] [Revised: 04/26/2007] [Accepted: 04/27/2007] [Indexed: 11/15/2022]
Abstract
Electroosmotic flows through hydrophobic microchannels experience velocity slip at the channel wall, which increases the volumetric flow rate at a given electric potential gradient. The conventional method of zeta potential estimation using the volumetric flow rate may yield quite inaccurate zeta potential unless the velocity slip is appropriately taken care of. In the present investigation we develop a method for simultaneous estimation of zeta potential and velocity slip coefficient in the electroosmotic flow through a hydrophobic microchannel using velocity measurements. The relevant inverse problem is solved through the minimization of a performance function utilizing a conjugate gradient method. The present method is found to estimate the zeta potential and slip coefficient accurately even with noisy velocity measurements.
Collapse
|
30
|
Park HM, Hong SM. Estimation of the zeta potential and the dielectric constant using velocity measurements in the electroosmotic flows. J Colloid Interface Sci 2006; 304:505-11. [PMID: 17046778 DOI: 10.1016/j.jcis.2006.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2006] [Revised: 09/08/2006] [Accepted: 09/08/2006] [Indexed: 11/21/2022]
Abstract
In this paper we develop a method for the determination of the zeta potential zeta and the dielectric constant epsilon by exploiting velocity measurements of the electroosmotic flow in microchannels. The inverse problem is solved through the minimization of a performance function utilizing the conjugate gradient method. The present method is found to estimate zeta and epsilon with reasonable accuracy even with noisy velocity measurements.
Collapse
|
31
|
|
32
|
Park HM, Shekhar Dhir C, Oh SH, Lee SY. A filter bank approach to independent component analysis for convolved mixtures. Neurocomputing 2006. [DOI: 10.1016/j.neucom.2005.09.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
|
33
|
Lee JS, Lee MK, Ha TY, Bok SH, Park HM, Jeong KS, Woo MN, Do GM, Yeo JY, Choi MS. Supplementation of whole persimmon leaf improves lipid profiles and suppresses body weight gain in rats fed high-fat diet. Food Chem Toxicol 2006; 44:1875-83. [PMID: 16904806 DOI: 10.1016/j.fct.2006.06.014] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2006] [Revised: 05/27/2006] [Accepted: 06/07/2006] [Indexed: 11/23/2022]
Abstract
The objective of this study was to investigate the hypolipidemic effects of powdered whole persimmon leaf supplement in rats fed high-fat diet. Three groups of male Sprague-Dawley rats during 6 weeks were fed different diet: normal control (NC), high-fat (HF), and high-fat supplemented with powdered whole persimmon leaf (PL; 5%, wt/wt) groups. Body weight and relative weight of interscapular brown adipose tissue were significantly lower in the PL group than in the HF group, while plasma leptin concentration was higher. The supplementation of persimmon leaf significantly lowered the plasma total cholesterol and triglyceride concentrations, whereas elevated the ratio of HDL-C/total-C and improved the atherogenic index. Persimmon leaf supplementation led the hepatic cholesterol and triglyceride values to similar levels to the NC group. Accumulation of hepatic lipid droplets and the epididymal white adipocyte size of PL group were diminished comparing to the HF group. Hepatic HMG-CoA and ACAT activities were significantly higher in the PL group than in other groups. Contents of fecal triglyceride, cholesterol and acidic sterol were significantly higher in the PL group than in the HF group. Accordingly, we suggest that supplementation of the powdered whole persimmon leaf improves plasma and hepatic lipid levels profile partly via the increased fecal lipids in high-fat fed rats. These beneficial effects may be due to the properties of its phenolic compounds (1.15 g/100g) and high fiber (63.48 g/100g) content in the powdered persimmon leaf.
Collapse
|
34
|
Park HM, Park MH, Kim YJ, Chun SH, Ahn JJ, Kim CI, Sung SH, Han WS, Kim SC. Mullerian adenosarcoma with sarcomatous overgrowth of the cervix presenting as cervical polyp: a case report and review of the literature. Int J Gynecol Cancer 2004; 14:1024-9. [PMID: 15361219 DOI: 10.1111/j.1048-891x.2004.014546.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
An aggressive variant of adenosarcoma, mullerian adenosarcoma with sarcomatous overgrowth (MASO) in the cervix is extremely rare. This variant contains obvious, high-grade sarcoma in addition to a low-grade form. In this report, we describe a case of MASO of the uterine cervix and review the clinical and pathological features of these tumors. The patient was a 37-year-old woman with a cervical polypoid mass, which was morphologically considered as a benign endocervical polyp. Microscopically, polypoid cervical mass showed diffuse and dense malignant spindle cell proliferation around the benign endocervical glands and also an area of markedly anaplastic and pleomorphic spindle cell proliferation, so called, sarcomatous overgrowth. Total abdominal hysterectomy and bilateral salpingo-oophorectomy with pelvic lymph node dissection were performed. The patient has been followed-up and neither chemotherapy nor other adjuvant therapies have been administered. At present, she has been clinically free of disease for 9 months since she received surgery. It is extremely rare that MASO of the uterine cervix is presented in premenopausal woman. Gynecologists and pathologists should be aware of the difficulties associated with a delay in the diagnosis of MASO when the tumor is present as a benign looking cervical polyp.
Collapse
|
35
|
Choi YK, Lee JY, Kim DY, Park JI, Jeong SW, Park HM, Park C. Uterine extramedullary plasmacytoma in a dog. Vet Rec 2004; 154:699-700. [PMID: 15200080 DOI: 10.1136/vr.154.22.699] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
|
36
|
Park HM, Oh SH, Lee SY. A filter bank approach to independent component analysis and its application to adaptive noise cancelling. Neurocomputing 2003. [DOI: 10.1016/s0925-2312(03)00438-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
37
|
Park HM, Sedrine WB, Reginster JY, Ross PD. Korean experience with the OSTA risk index for osteoporosis: a validation study. J Clin Densitom 2003; 6:247-50. [PMID: 14514994 DOI: 10.1385/jcd:6:3:247] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/14/2002] [Accepted: 01/25/2003] [Indexed: 11/11/2022]
Abstract
The Osteoporosis Self-assessment Tool for Asians (OSTA) was developed to help physicians focus their efforts on patients at increased risk, and encourage appropriate use of bone mineral density (BMD) measurements. Previously, OSTA performed well in a sample of women from eight countries in Asia, and in a validation group of Japanese women. In this study, we evaluate the performance of OSTA using a sample of 1101 postmenopausal women from a clinic in Korea who had femoral neck BMD measurements by dual-energy X-ray absorptiometry (DXA). The OSTA had a high sensitivity (87%), and good specificity (67%) for identifying osteoporosis (BMD T-scores <or= -2.5); the corresponding values were 80% and 72% for identifying T-scores <or= -2.0. The prevalence of osteoporosis ranged from 2% among women classified as low risk (OSTA > -1) to 64% among those classified as high risk (OSTA < -4); these results were almost identical to those reported earlier for a sample of women from eight Asian countries. We conclude that the OSTA risk tool performed well in this sample of postmenopausal Korean women, similar to previous results in other Asian women. The OSTA tool is free and very easy to use; risk can be tabulated by age and weight, so that calculations are not necessary. Using OSTA could encourage patients and clinicians to actively assess osteoporosis, and measure BMD when appropriate, before fractures occur.
Collapse
|
38
|
Park HM, Jung SW, Rhee CK. Vestibular diagnosis as prognostic indicator in sudden hearing loss with vertigo. ACTA OTO-LARYNGOLOGICA. SUPPLEMENTUM 2002; 545:80-3. [PMID: 11677749] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/22/2023]
Abstract
The majority of episodes of sudden hearing loss are caused by inner ear disorders, often accompanied by vertigo. The patterns of hearing loss usually influence the prognosis. The purpose of this study was to analyze vestibular diagnoses in sudden hearing loss with vertigo, and to correlate them with the recovery of hearing loss. The clinical records of 125 patients with sudden hearing loss were reviewed. Various vestibular evaluations were performed in 36 patients with vertigo. The vertigo in these patients was classified as normal, unilateral hypofunction, directional preponderance, benign paroxysmal positional vertigo (BPPV), non-specific or irritative. The initial and final pure-tone audiograms of these patients were compared. The distribution of vestibular diagnoses was unilateral hypofunction in 30.6% of patients, BPPV in 25.7%, normal in 19.4%, non-specific in 11.1%, directional preponderance in 8.3% and irritative in 8.3%. The recovery of hearing in patients with vertigo was significantly worse than in those without vertigo. The recovery of hearing in patients with spinning vertigo did not differ from that of patients with non-spinning vertigo. The recovery of hearing was worst in the BPPV group, especially in the high frequency range, followed by the unilateral hypofunction group, who showed hearing thresholds between those in the BPPV group and those in the normal vestibular function test group. This study suggests that the diagnostic classification of vestibulopathy is a useful prognostic indicator of hearing recovery in sudden hearing loss with vertigo. We conclude that otolithic and semicircular canal involvement may cause poor hearing results, especially in the high frequency range.
Collapse
|
39
|
Kim KH, Cho YM, Kang WH, Kim JH, Byun KH, Park YD, Bae KS, Park HM. Negative regulation of filamentous growth and flocculation by Lkh1, a fission yeast LAMMER kinase homolog. Biochem Biophys Res Commun 2001; 289:1237-42. [PMID: 11741326 DOI: 10.1006/bbrc.2001.6128] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
We have isolated a full-length cDNA clone that encodes for a Schizosaccharomyces pombe homolog of the dual-specificity protein kinase of the LAMMER family, lkh1 (lammer kinase homolog). The proposed Lkh1 protein contains 575 amino acids. The lkh1(+) null mutant is viable, but exhibits flocculation upon reaching stationary phase in liquid media and filamentous adhesion growth on solid media. Analysis of the flocculation activity of the lkh1(+) null mutant indicates that asexual aggregation of S. pombe cells into floccules is divalent cation-dependent and galactose-specific. We also demonstrate that the Saccharomyces cerevisiae LAMMER kinase homolog, Kns1, can substitute for the Lkh1 function in S. pombe.
Collapse
|
40
|
Takahashi H, Ahn JK, Akikawa H, Aoki S, Arai K, Bahk SY, Baik KM, Bassalleck B, Chung JH, Chung MS, Davis DH, Fukuda T, Hoshino K, Ichikawa A, Ieiri M, Imai K, Iwata YH, Iwata YS, Kanda H, Kaneko M, Kawai T, Kawasaki M, Kim CO, Kim JY, Kim SJ, Kim SH, Kondo Y, Kouketsu T, Lee YL, McNabb JW, Mitsuhara M, Nagase Y, Nagoshi C, Nakazawa K, Noumi H, Ogawa S, Okabe H, Oyama K, Park HM, Park IG, Parker J, Ra YS, Rhee JT, Rusek A, Shibuya H, Sim KS, Saha PK, Seki D, Sekimoto M, Song JS, Takahashi T, Takeutchi F, Tanaka H, Tanida K, Tojo J, Torii H, Torikai S, Tovee DN, Ushida N, Yamamoto K, Yasuda N, Yang JT, Yoon CJ, Yoon CS, Yosoi M, Yoshida T, Zhu L. Observation of a (6)(LambdaLambda)He double hypernucleus. PHYSICAL REVIEW LETTERS 2001; 87:212502. [PMID: 11736336 DOI: 10.1103/physrevlett.87.212502] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2001] [Indexed: 05/23/2023]
Abstract
A double-hyperfragment event has been found in a hybrid-emulsion experiment. It is identified uniquely as the sequential decay of ( 6)(LambdaLambda)He emitted from a Xi(-) hyperon nuclear capture at rest. The mass of ( 6)(LambdaLambda)He and the Lambda-Lambda interaction energy DeltaB(LambdaLambda) have been measured for the first time devoid of the ambiguities due to the possibilities of excited states. The value of DeltaB(LambdaLambda) is 1.01+/-0.20(+0.18)(-0.11) MeV. This demonstrates that the Lambda-Lambda interaction is weakly attractive.
Collapse
|
41
|
Yasui A, Oda K, Usunomiya H, Kakudo K, Suzuki T, Yoshida T, Park HM, Fukazawa K, Muramatsu T. Elevated gastrin secretion by in vivo gene electroporation in skeletal muscle. Int J Mol Med 2001; 8:489-94. [PMID: 11605015 DOI: 10.3892/ijmm.8.5.489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Whether or not in vivo gene transfer of gastrin gene into skeletal muscle by electroporation could modify gastrin secretion was examined. The expression plasmid vector, either pMEPrGaspA encoding the rat gastrin gene or pEGFP-N1 encoding the GFP reporter gene was injected into M. rectus abdominis of rats or M. biceps formis of mice. Subsequently, square electric pulses of direct current were applied six times at 25 V with a loading period of 100 msec per pulse. Clear foreign gene expression in the skeletal muscle was demonstrated by both GFP fluorescence and immunostaining of rat gastrin. Time course changes in plasma gastrin levels after transfection revealed that in rats, gastrin gene transfer significantly increased the plasma gastrin level for 4 weeks post-transfection (P<0.05), but the difference diminished at the end of the 10-week period. In mice, plasma gastrin level elevated similarly for 3 weeks, and pH of gastric contents decreased in the gastrin gene transfected group compared with the control counterpart (P<0.05). These findings suggest that localized in vivo gene transfer by electroporation allows skeletal muscle to become an artificial endocrine tissue for hormonal manipulation of animals.
Collapse
|
42
|
Chung IJ, Choi YS, Hong SW, Park HM. Immobilization of arsenic in tailing by using iron and hydrogen peroxide. ENVIRONMENTAL TECHNOLOGY 2001; 22:831-835. [PMID: 11506207 DOI: 10.1080/095933322086180325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Under environmental conditions, arsenic (As) reveals anionic behavior and is converted into various forms in accordance with the Eh/pH condition. This causes the difficulty of treating As with other heavy metals in tailing. This study was carried out to develop the immobilization method of arsenic in tailing as ferric arsenate (FeAsO4) using hydrogen peroxide. According to experimental results, the extracted concentrations of arsenic and iron (Fe) from tailing were reduced up to 84% and 93%, respectively. In the experiment using pure Pyrite (FeS2) and As solution, As concentration decreased with an increase of hydrogen peroxide dosage. The experimental results of re-extraction showed that only 10% of As and 20% of Fe were extracted in the case of using hydrogen peroxide. As a result, the long-term stability of this method was clarified.
Collapse
|
43
|
Koh LK, Sedrine WB, Torralba TP, Kung A, Fujiwara S, Chan SP, Huang QR, Rajatanavin R, Tsai KS, Park HM, Reginster JY. A simple tool to identify asian women at increased risk of osteoporosis. Osteoporos Int 2001; 12:699-705. [PMID: 11580084 DOI: 10.1007/s001980170070] [Citation(s) in RCA: 318] [Impact Index Per Article: 13.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Patients with low bone mineral density (BMD) have a high risk of future fractures, and should be actively considered for treatment to reduce their risk. However, BMD measurements are not widely available in some communities, because of cost and lack of equipment. Simple questionnaires have been designed to help target high-risk women for BMD measurements, thereby avoiding the cost of measuring women at low risk. However, such tools have previously focused on evaluation of non-Asian women. We collected information about numerous risk factors from postmenopausal Asian women in eight countries in Asia using questionnaires, and evaluated the ability of these risk factors to identify women with osteoporosis as defined by femoral neck BMD T-scores < or =-2.5. Multiple variable regression analysis and item reduction yielded a final tool based on only age and body weight. This risk index had a sensitivity of 91% and specificity of 45%, with an area under the curve of 0.79. Previously published risk indices based on larger numbers of variables performed similarly well in this Asian population. Large differences in risk were identified using our index to create three categories: 61% of the high-risk women had osteoporosis, compared with only 15% and 3% of the intermediate- and low-risk women, respectively. The low-risk group represented 40% of all women, for whom BMD measurements are probably not needed unless important risk factors, such as prior nonviolent fracture or corticosteroid use, are present. An existing population-based sample of postmenopausal Japanese women was used to validate our index. In this sample of Japanese women the sensitivity was 98% and specificity was 29%; the low-risk category, for whom BMD is probably unnecessary, represented 25% of all women. We conclude that our index performed well for classifying the risk of osteoporosis among postmenopausal Asian women and applying it would result in more prudent use of BMD technology.
Collapse
|
44
|
Muramatsu T, Arakawa S, Fukazawa K, Fujiwara Y, Yoshida T, Sasaki R, Masuda S, Park HM. In vivo gene electroporation in skeletal muscle with special reference to the duration of gene expression. Int J Mol Med 2001; 7:37-42. [PMID: 11115606 DOI: 10.3892/ijmm.7.1.37] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To determine the limits of the duration of in vivo transferred foreign gene expression, we conducted electroporation (EP), a powerful non-viral means of gene transfer for living animals, into skeletal muscle of rats and mice with a luciferase, GFP or erythropoietin (EPO)-encoding reporter plasmid. The luciferase reporter plasmid was used for optimization of EP conditions, while GFP and EPO plasmids were used for monitoring the duration of gene expression. In the rat, increased hematocrit levels were maintained for at least 9 weeks with approximately a 3-fold increase in plasma EPO protein concentration at 4 weeks post-transfection. In the mouse, the GFP plasmid transfer confirmed that the reporter gene expression lasted as long as 3 months post-transfection. By introducing the EPO gene in vivo in the mouse, increased hematocrit levels revealed that duration of reporter gene expression was at least 14.5 months after in vivo gene EP into skeletal muscle. These results implicate an excellent potential of in vivo gene EP, applicable to both experimental and therapeutic purposes.
Collapse
|
45
|
Muramatsu T, Ito N, Tamaoki N, Oda H, Park HM. In vivo gene electroporation confers nutritionally-regulated foreign gene expression in the liver. Int J Mol Med 2001; 7:61-6. [PMID: 11115610 DOI: 10.3892/ijmm.7.1.61] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Whether or not nutritionally-regulated foreign gene expression in vivo is achievable was examined in mouse liver after in vivo gene transfer by electroporation (EP). Electric pulses were applied to a left liver lobe immediately after injection of a luciferase reporter gene driven by the liver-type phosphoenolpyruvate carboxykinase (PEPCK) gene promoter. Cooling treatments especially with solid carbon dioxide in the transfection site prior to the in vivo gene EP increased reporter gene expression by a factor of 100. Body bioluminescence imaging also confirmed strong expression of the in vivo transferred reporter gene in a transfected area of the liver. Fasting conferred a 13-fold increase in the reporter gene expression in vivo in the liver when driven by the liver-type PEPCK promoter, whereas virtually no induction was found either by the SV40 promoter or by the same PEPCK promoter in the muscle when the mice were fasted. The administration of cAMP mimicked the fasting-induced reporter gene expression by the PEPCK promoter in the liver of fed mice. These results implicate that nutritionally-regulated foreign gene expression in vivo is attainable at least locally in the liver by a simple and convenient non-viral gene EP method.
Collapse
|
46
|
Lee MW, Lee YA, Park HM, Toh SH, Lee EJ, Jang HD, Kim YH. Antioxidative phenolic compounds from the roots of Rhodiola sachalinensis A. Bor. Arch Pharm Res 2000; 23:455-8. [PMID: 11059822 DOI: 10.1007/bf02976571] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
The acetone extract of the roots of Rhodiola sachalinensis has furnished six phenolic compounds which exhibited significant scavenging effects against DPPH free radical. The structures of these compounds were identified and determined as gallic acid (1), (-)-epigallocatechin 3-O-gallate (2), kaempferol (3), kaempferol 7-O-alpha-L-rhamnopyranoside (4), herbacetin 7-O-alpha-L-rhamnopyranoside, (5) and rhodiolinin (6) by physico-chemical and spectral evidences.
Collapse
|
47
|
Sugihara K, Park HM, Muramatsu T. In vivo gene electroporation confers strong transient expression of foreign genes in the chicken testis. Poult Sci 2000; 79:1116-9. [PMID: 10947179 DOI: 10.1093/ps/79.8.1116] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
To attain foreign gene expression in vivo in the testis of living chickens, chloramphenicol acetyltransferase (CAT) and firefly luciferase reporter genes were transfected by electroporation (EP). Bioluminescence imaging indicated clear expression of the luciferase reporter gene localized in and around the injection site of the chicken testis. The CAT activity decreased sharply from 7 to 14 d posttransfection (P < 0.01) and remained low until 28 d. The presence of the self-replication sequence of Epstein-Barr virus did not give significantly higher CAT gene expression over the 28-d posttransfection. The results suggest that in vivo gene EP confers strong, likely transient, foreign gene expression in the testis of living chickens.
Collapse
|
48
|
Park HM, Haecker SE, Hagen SG, Sanders MM. COUP-TF plays a dual role in the regulation of the ovalbumin gene. Biochemistry 2000; 39:8537-45. [PMID: 10913260 DOI: 10.1021/bi0005862] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The ovalbumin (Ov) gene contains a number of regulatory elements that control its transcriptional activity and restrict expression to avian oviduct. One major regulatory region, the steroid-dependent regulatory element (SDRE), is required for induction by estrogen and corticosterone. Another region, the negative regulatory element (NRE), downstream of the SDRE, acts primarily to repress gene expression. In addition, experiments within indicate that the binding site for the COUP transcription factor (COUP-TF) is also required for Ov gene transcription. To examine the interactions involving the SDRE, the NRE, and the COUP binding sites on Ov gene transcription, mutations in these regions were made and transfected into primary oviduct cell cultures. These experiments show that without the NRE, the SDRE is sufficient for induction by estrogen and corticosterone, irrespective of the COUP site. However, with the NRE intact, the COUP site is required for steroid induction, although without the NRE, the COUP site attenuates transcriptional activity. More interestingly, overexpression of COUP-TF1 with the Ov wild-type reporter construct alleviates the requirement for steroid hormones. These results demonstrate that the COUP site is essential and has a dual role in Ov gene transcription and that steroid hormones might directly or indirectly regulate the activity of COUP-TF1.
Collapse
|
49
|
Bang KH, Lee DW, Park HM, Rhee YH. Inhibition of fungal cell wall synthesizing enzymes by trans-cinnamaldehyde. Biosci Biotechnol Biochem 2000; 64:1061-3. [PMID: 10879482 DOI: 10.1271/bbb.64.1061] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
This study examined the inhibitory effects of trans-cinnamaldehyde (CA), an aromatic aldehyde derived from Cinnamomi Cortex, on Saccharomyces cerevisiae cell wall synthesizing enzymes in vitro. This compound was found to be a noncompetitive inhibitor of beta-(1,3)-glucan synthase and a mixed inhibitor of chitin synthase 1 with 50% inhibitory concentrations (IC50) of 0.84 and 1.44 mM, respectively. Chitin synthases 2 and 3 were less sensitive than chitin synthase 1 to CA. CA can be useful as a model compound of cell wall inhibitors for the development of effective antifungal agents.
Collapse
|
50
|
Wagner JD, Corbett L, Park HM, Davidson D, Coleman JJ, Havlik RJ, Hayes JT. Sentinel lymph node biopsy for melanoma: experience with 234 consecutive procedures. Plast Reconstr Surg 2000; 105:1956-66. [PMID: 10839392 DOI: 10.1097/00006534-200005000-00007] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Sentinel lymph node biopsy is increasingly used to identify occult metastases in regional lymph nodes of patients with melanoma. Selection of patients for sentinel lymph node biopsy and subsequent lymphadenectomy is an area of debate. The purpose of this study was to describe a large clinical series of these biopsies for cutaneous melanoma and to identify patients most likely to gain useful clinical information from sentinel lymph node biopsy. The Indiana University Melanoma Program computerized database was queried to identify all patients who underwent this procedure for clinically localized cutaneous melanoma. It was performed using preoperative technetium Tc 99m lymphoscintigraphy and isosulfan blue dye. Pertinent demographic, surgical, and histopathologic data were recorded. Univariate and multivariate logistic regression and classification table analyses were performed to identify clinical variables associated with sentinel node and nonsentinel node positivity. In total, 234 biopsy procedures were performed to stage 291 nonpalpable regional lymph node basins. Mean Breslow's thickness was 2.30 mm (2.08 mm for negative sentinel lymph node biopsy, 3.18 mm for positive). The mean number of sentinel nodes removed was 2.17 nodes per basin (range, 1 to 8). Forty-seven of 234 melanomas (20.1 percent) and 50 of 291 basins (17.2 percent) had a positive biopsy. Positivity correlated with AJCC tumor stage: T1, 3.6 percent; T2, 8.1 percent; T3, 27.4 percent; T4, 44 percent. By univariate logistic regression, Breslow's thickness (p = 0.003, continuous variable), ulceration (p = 0.003), mitotic index > or = 6 mitoses per high power field (p = 0.008), and Clark's level (p = 0.04) were significantly associated with sentinel lymph node biopsy result. By multivariate analysis, only Breslow's thickness (p = 0.02), tumor ulceration (p = 0.02), and mitotic index (p = 0.02) were significant predictors of biopsy positivity. Classification table analysis showed the Breslow cutpoint of 1.2 mm to be the most efficient cutpoint for sentinel lymph node biopsy result (p = 0.0004). Completion lymphadenectomy was performed in 46 sentinel node-positive patients; 12 (26.1 percent) had at least one additional positive nonsentinel node. Nonsentinel node positivity was marginally associated with the presence of multiple positive sentinel nodes (p = 0.07). At mean follow-up of 13.8 months, four of 241 sentinel node-negative basins demonstrated same-basin recurrence (1.7 percent). Sentinel lymph node biopsy is highly reliable in experienced hands but is a low-yield procedure in most thin melanomas. Patients with melanomas thicker than 1.2 mm or with ulcerated or high mitotic index lesions are most likely to have occult lymph node metastases by sentinel lymph node biopsy. Completion therapeutic lymphadenectomy is recommended after positive biopsy because it is difficult to predict the presence of positive nonsentinel nodes.
Collapse
|