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Search Results: 1 - 10 of 5297 matches for " Choi KC "
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Hair dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation
Lee HY, Jeong YI, Choi KC
International Journal of Nanomedicine , 2011, DOI: http://dx.doi.org/10.2147/IJN.S26458
Abstract: ir dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation Original Research (3575) Total Article Views Authors: Lee HY, Jeong YI, Choi KC Published Date November 2011 Volume 2011:6 Pages 2879 - 2888 DOI: http://dx.doi.org/10.2147/IJN.S26458 Hye-Young Lee1,*, Young-IL Jeong2,*, Ki-Choon Choi3 1Anyang Science University, Anyang, Gyeonggi, South Korea; 2Chonnam National University Hwasun Hospital, Jeonnam, South Korea; 3Grassland and Forages Research Center, National Institute of Animal Science, Rural Development Administration, Chungnam, South Korea *These authors contributed equally to this work. Background: p-Phenylenediamine (PDA) or its related chemicals are used more extensively than oxidative hair dyes. However, permanent hair dyes such as PDA are known to have potent contact allergy reactions in humans, and severe allergic reactions are problematic. Methods: PDA-incorporated nanoparticles were prepared based on ion-complex formation between the cationic groups of PDA and the anionic groups of poly(γ-glutamic acid) (PGA). To reinforce PDA/PGA ion complexes, glycol chitosan (GC) was added. PDA-incorporated nanoparticles were characterized using field-emission scanning electron microscopy, Fourier-transform infrared (FT-IR) spectroscopy, dynamic light scattering, and powder X-ray diffractometry (XRD). Results: Nanoparticles were formed by ion-complex formation between the amine groups of PDA and the carboxyl groups of PGA. PDA-incorporated nanoparticles are small in size (<100 nm), and morphological observations showed spherical shapes. FT-IR spectra results showed that the carboxylic acid peak of PGA decreased with increasing PDA content, indicating that the ion complexes were formed between the carboxyl groups of PGA and the amine groups of PDA. Furthermore, the intrinsic peak of the carboxyl groups of PGA was also decreased by the addition of GC. Intrinsic crystalline peaks of PDA were observed by XRD. This crystalline peak of PDA was completely nonexistent when nanoparticles were formed by ion complex between PDA, PGA, and GC, indicating that PDA was complexed with PGA and no free drug existed in the formulation. During the drug-release experiment, an initial burst release of PDA was observed, and then PDA was continuously released over 1 week. Cytotoxicity testing against HaCaT human skin keratinocyte cells showed PDA-incorporated nanoparticles had lower toxicity than PDA itself. Furthermore, PDA-incorporated nanoparticles showed reduced apoptosis and necrosis reaction at HaCaT cells. Conclusion: The authors suggest that these microparticles are ideal candidates for a vehicle for decreasing side effects of hair dye.
Hair dye-incorporated poly-γ-glutamic acid/glycol chitosan nanoparticles based on ion-complex formation
Lee HY,Jeong YI,Choi KC
International Journal of Nanomedicine , 2011,
Abstract: Hye-Young Lee1,*, Young-IL Jeong2,*, Ki-Choon Choi31Anyang Science University, Anyang, Gyeonggi, South Korea; 2Chonnam National University Hwasun Hospital, Jeonnam, South Korea; 3Grassland and Forages Research Center, National Institute of Animal Science, Rural Development Administration, Chungnam, South Korea*These authors contributed equally to this work.Background: p-Phenylenediamine (PDA) or its related chemicals are used more extensively than oxidative hair dyes. However, permanent hair dyes such as PDA are known to have potent contact allergy reactions in humans, and severe allergic reactions are problematic.Methods: PDA-incorporated nanoparticles were prepared based on ion-complex formation between the cationic groups of PDA and the anionic groups of poly(γ-glutamic acid) (PGA). To reinforce PDA/PGA ion complexes, glycol chitosan (GC) was added. PDA-incorporated nanoparticles were characterized using field-emission scanning electron microscopy, Fourier-transform infrared (FT-IR) spectroscopy, dynamic light scattering, and powder X-ray diffractometry (XRD).Results: Nanoparticles were formed by ion-complex formation between the amine groups of PDA and the carboxyl groups of PGA. PDA-incorporated nanoparticles are small in size (<100 nm), and morphological observations showed spherical shapes. FT-IR spectra results showed that the carboxylic acid peak of PGA decreased with increasing PDA content, indicating that the ion complexes were formed between the carboxyl groups of PGA and the amine groups of PDA. Furthermore, the intrinsic peak of the carboxyl groups of PGA was also decreased by the addition of GC. Intrinsic crystalline peaks of PDA were observed by XRD. This crystalline peak of PDA was completely nonexistent when nanoparticles were formed by ion complex between PDA, PGA, and GC, indicating that PDA was complexed with PGA and no free drug existed in the formulation. During the drug-release experiment, an initial burst release of PDA was observed, and then PDA was continuously released over 1 week. Cytotoxicity testing against HaCaT human skin keratinocyte cells showed PDA-incorporated nanoparticles had lower toxicity than PDA itself. Furthermore, PDA-incorporated nanoparticles showed reduced apoptosis and necrosis reaction at HaCaT cells.Conclusion: The authors suggest that these microparticles are ideal candidates for a vehicle for decreasing side effects of hair dye.Keywords: p-phenylenediamine, keratinocyte, PDA, PGA
All-trans retinoic acid-incorporated nanoparticles of deoxycholic acid-conjugated dextran for treatment of CT26 colorectal carcinoma cells
Jeong YI, Chung KD, Kim DH, Kim YH, Lee YS, Choi KC
International Journal of Nanomedicine , 2013, DOI: http://dx.doi.org/10.2147/IJN.S40580
Abstract: ll-trans retinoic acid-incorporated nanoparticles of deoxycholic acid-conjugated dextran for treatment of CT26 colorectal carcinoma cells Original Research (872) Total Article Views Authors: Jeong YI, Chung KD, Kim DH, Kim YH, Lee YS, Choi KC Published Date January 2013 Volume 2013:8 Pages 485 - 493 DOI: http://dx.doi.org/10.2147/IJN.S40580 Received: 21 November 2012 Accepted: 28 December 2012 Published: 30 January 2013 Young Il Jeong,1,* Kyu Don Chung,2,* Da Hye Kim,3 Yoon Hyuk Kim,4 Yeon Soo Lee,5 Ki Choon Choi3 1Cancer Center, Chonnam National University Hwasun Hospital, Hwasun, South Korea; 2Department of Anesthesiology and Pain Medicine, Catholic University, Seoul, South Korea; 3Grassland and Forage Research Center, Rural Development Administration, Cheonan, South Korea; 4Department of Mechanical Engineering, Kyung Hee University, Seoul, South Korea; 5Department of Biomedical Engineering, Catholic University of Daegu, Daegu, South Korea *These authors equally contributed to this work Purpose: All-trans retinoic acid (RA)-incorporated nanoparticles were prepared using deoxycholic acid-conjugated dextran (DexDA). Anticancer activity of RA-incorporated DexDA nanoparticles were tested in vitro and in vivo. Methods: RA-incorporated nanoparticles were prepared by dialysis. Antiproliferative and anti-invasive potential of RA-incorporated nanoparticles were studied using CT26 colorectal carcinoma cells. Results: RA-incorporated nanoparticles have small particle sizes of around 70–300 nm and spherical shapes. The higher drug-feeding ratio and higher substitution degree of deoxycholic acid in the conjugates resulted in higher drug contents, lower loading efficiency, and larger particle size. RA release rate became slower at higher drug contents and higher substitution degree of deoxycholic acid in the DexDA conjugates. The antiproliferation activity, anti-invasive activity, and matrix metalloproteinase 2 expression of RA-incorporated nanoparticles against CT26 cells in vitro was similar to RA. However, RA-incorporated nanoparticles had superior antimetastatic activity in an animal pulmonary metastatic model of CT26 cells compared to RA itself. Conclusion: RA-incorporated nanoparticles showed similar anticancer activity in vitro and superior antimetastatic activity in vivo in a pulmonary metastatic model of CT26 cells. We suggest that RA-incorporated nanoparticles are promising vehicles for efficient delivery of RA.
Low Profile Visualized Intraluminal Support (LVIS) Stent in Endovascular Coil Embolization of Cerebral Aneurysms: A Review  [PDF]
Ujjwol KC, Gang Deng
Open Journal of Radiology (OJRad) , 2019, DOI: 10.4236/ojrad.2019.92009
Abstract:
Cerebral or intracranial aneurysm is a leading cause of subarachnoid hemorrhage. It was initially treated with open surgical clipping but as rapid development of technology a less invasive endovascular coiling technique of aneurysm revolutionized the treatment. Due to tortuous anatomy of parent artery and complicated morphology and location of aneurysm there is ongoing challenge in the complete obliteration of aneurysms. To aid in the advances of treating aneurysm stent assisted endovascular coiling was introduced to give more scaffold support to parent artery and decrease events of coil protrusion from aneurysms. Many types and generation of stents were developed. One of the most recently introduced stent is low profile visualized intraluminal support (LVIS) stent. Due to its low profile nature it can be used in 0.017-inch inner diameter microcatheter and reach small and complex vessels providing high aneurysmal neck coverage which was not possible through other traditional stent. In addition, its braided design with tantalum strands and radiopaque markers make it more visible during stent placement and post procedure stent evaluation. Despite of many advantages of LVIS stent it is related to high rate of thromboembolic complications and technical complications. Aim of this review paper was to evaluate therapeutic safety, effectiveness and feasibility of LVIS stent in endovascular coil embolization of intracranial aneurysms.
How can schools build learning organisations in difficult education contexts?
KC Moloi
South African Journal of Education , 2010,
Abstract: There is paucity in the study of learning organisations within the education sector and particularly in schools working in difficult socio-economic contexts, such as those studied in this investigation. In this qualitative study I therefore sought evidence from teachers, in one of the districts of Gauteng province, through in-depth, semi-structured focus group interviews to establish what a learning organisation is. Using data obtained through two in-depth, semistructured focus group interviews with 16 teachers, themes were constructed to theorise their experiences on what a learning organisation is. The results showed that teacher commitment to personal learning enhanced student achievement. This study contributes to the understanding of theories on learning organisations from the experiences of these teachers working in disadvantaged townships schools.
Corneal biomechanical parameters and intraocular pressure: the effect of topical anesthesia
Ogbuehi KC
Clinical Ophthalmology , 2012, DOI: http://dx.doi.org/10.2147/OPTH.S32322
Abstract: rneal biomechanical parameters and intraocular pressure: the effect of topical anesthesia Original Research (1736) Total Article Views Authors: Ogbuehi KC Published Date June 2012 Volume 2012:6 Pages 871 - 878 DOI: http://dx.doi.org/10.2147/OPTH.S32322 Received: 28 March 2012 Accepted: 20 April 2012 Published: 21 June 2012 Kelechi C Ogbuehi Cornea Research Chair, Department of Optometry and Vision Sciences, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia Background: The intraocular pressures and biomechanical parameters measured by the ocular response analyzer make the analyzer a useful tool for the diagnosis and management of anterior segment disease. This observational study was designed to investigate the effect of topical anesthesia on the parameters measured by the ocular response analyzer: corneal hysteresis, corneal resistance factor, Goldmann-correlated intraocular pressure (IOPg), and corneal-compensated intraocular pressure (IOPcc). Methods: Two sets of measurements were made for 78 eyes of 39 subjects, approximately 1 week apart. In session 1, each eye of each subject was randomized into one of three groups: polyvinyl alcohol (0.5%), tetracaine hydrochloride (0.5%), or oxybuprocaine hydrochloride (0.4%). In session 2, eyes that were in the polyvinyl alcohol group in session 1 were assigned to the tetracaine group, those in the tetracaine group in session 1 were assigned to oxybuprocaine group, and those in the oxybuprocaine group in session 1 were assigned to the polyvinyl alcohol group. For both sessions, each subject first had his or her central corneal thickness assessed with a specular microscope, followed by measurements of intraocular pressure and corneal biomechanical parameters with the Ocular Response Analyzer. All measurements were repeated for 2 minutes and 5 minutes following the instillation of either polyvinyl alcohol, tetracaine, or oxybuprocaine. The level of statistical significance was 0.05. Results: Polyvinyl alcohol, tetracaine hydrochloride, and oxybuprocaine hydrochloride had no statistically significant (P > 0.05) effect on any of the biomechanical parameters of the cornea. There was no statistically significant effect on either IOPg (P > 0.05) or IOPcc (P > 0.05) 2 minutes after the eye drops were instilled in either session. Five minutes after the eye drops were instilled, polyvinyl alcohol showed no statistically significant effect on either IOPg (P > 0.05) or IOPcc (P > 0.05) in either session. Oxybuprocaine and tetracaine caused statistically significant (P < 0.05) reductions in IOPg in session 1, but only tetracaine had a significant (P < 0.05) effect in session 2. Tetracaine also caused a statistically significant (P < 0.05) reduction in IOPcc in session 1. Conclusion: The statistically significant effect of topical anesthesia on IOPg varies with the anesthetic used, and while this effect was statistically significant in this study, the small effect is probably not clinicall
AN ADULT PATIENT WITH NAIL ABNORMALITY
KOH KC
Malaysian Family Physician , 2011,
Abstract:
WHO 2009 GUIDELINES FOR ANTI-RETROVIRAL THERAPHY: ITS IMPLICATION FOR PRIMARY CARE PHYSICIAN
KOH KC
Malaysian Family Physician , 2010,
Abstract: -The HIV epidemic in Malaysia is slowing down but has now spread to spouses and sexual partners of traditional at risk populations, via heterosexual transmission. -The WHO 2009 guideline advocates starting HAART at CD4 level of 350 cells/mm3, marking a significant departure from starting at CD4 level of 200 cells/mm3 previously. -The WHO 2009 guideline recommended replacing stavudine with either zidovudine or tenofovir as part of the first line HAART regimen due to the former’s adverse effects. -Early detection of HIV infection and earlier initiation of HAART translates into better quality of life and lower risk of Tuberculosis co-infection. -Earlier detection of HIV infection requires picking up on subtle signs of the infection as well as employing a host of available diagnostic tests in cases where HIV infection is strongly suspected. -HIV test should be offered as a part of a routine health check screening. This facilitates early detection of HIV infection and early referral to the hospital for further management. -Collaboration and communications with non-governmental organizations involved in care of HIV infected people can be a good mean of providing support and counselling to newly diagnosed HIV infected individuals. -Asymptomatic undiagnosed HIV infected patients may pose a risk for disease transmission to health care workers in the primary care setting. Steps must be taken to minimize the risk of transmission and easy access to post-exposure prophylaxis. -The primary care physician should be well versed with the many possible drug interactions between HAART and other commonly used medications for other illnesses in order to avoid potentially fatal adverse reactions or treatment failure in patients taking HAART.
Impact of extended-release dalfampridine on walking ability in patients with multiple sclerosis
Hayes KC
Neuropsychiatric Disease and Treatment , 2011,
Abstract: Keith C HayesDepartment of Physical Medicine and Rehabilitation, The University of Western Ontario, London, ON, CanadaAbstract: Dalfampridine extended release (ER) 10 mg is an oral tablet form of the potassium (K+) channel-blocking compounded dalfampridine, also known as fampridine, and chemically 4-aminopyridine or 4-AP, which received regulatory approval in the United States for the treatment of walking in patients with multiple sclerosis (MS) in January 2010. Two pivotal Phase 3 clinical trials demonstrated significant improvements in walking in patients with the four primary forms of MS following administration of dalfampridine ER tablets 10 mg twice daily. The drug is thought to act by restoring conduction in focally demyelinated axons and by enhancing neurotransmission, thereby leading to improved neurological function. This review describes how dalfampridine represents a new pharmacotherapeutic approach to the clinical management of mobility impairment. It describes the mechanism of action and chemistry of dalfampridine ER, its pharmacokinetics, tolerability, and side effects, and the outcomes of multicenter trials showing its efficacy in improving walking speed. Clinician and patient global assessments, as well as patient self-assessment of the impact of MS on their gait disability, confirm clinically relevant benefit from the therapy. Patients tolerate the drug well and their improvement in terms of household and community ambulation, inferred from analysis of pooled data from several studies, is likely to translate into benefits in the performance of instrumental activities of daily living and a reduction in the neuropsychiatric burden of disease.Keywords: dalfampridine ER, Ampyra , fampridine-SR, 4-aminopyridine, multiple sclerosis, demyelination
Burn-out-Syndrom - erkennen und verhindern
Steinwachs KC
Blickpunkt der Mann , 2009,
Abstract:
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