• Applied Chemistry for Engineering
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• v.32 no.5
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• pp.509-515
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• 2021

In this study, poly lactic-co-glycolic acid (PLGA) nanoparticles (PNP) were prepared through double (w/o/w) emlusion and emulsifying solvent-evaporation technique using PLGA, which has biocompatibility and biodegradability. To maximize stability and bioavailability of the particles, chitosan-coated PLGA nanoparticles (CPNP) were prepared by charge interaction between PNP and chitosan. We demonstrated that CPNP can be utilized as a drug carrier of oral administration. The chemical structure of CPNP was analyzed by ¹H-NMR and FT-IR, and all characteristic peaks appeared, confirming that it was successfully prepared. In addition, particle size and zeta potential of CPNP were analyzed using dynamic light scattering (DLS) while morphological images were obtained using transmission electron microscope (TEM). Thermal decomposition behavior of CPNP was observed through thermogravimetric analysis (TGA). In addition, the cytotoxicity of CPNP was confirmed by MTT assay at HEK293 and L929 cell lines, and it was proved that there is no toxicity confirmed by the cell viability of above 70% at all concentrations. These results suggest that the CPNP developed in this study may be used as an oral drug delivery carrier.

• The Journal of Korea Assosiation for Disability and Oral Health
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• v.6 no.2
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• pp.77-83
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• 2010

This article discusses the issues of benefit and risk associated with outpatient general anesthesia and deep sedation for the special need dental patients. The purpose of administering anesthesia for patients with special needs is to provide effect dental treatment. But there are many complications such as sore throat, nausea and vomiting, airway trauma, airway obstruction and hypoxic brain damages, etc. In order to decrease incidence of complication, before general anesthesia meticulous patient evaluation is much important. But, there are a number of factors that make it difficult to accurately assess the anesthetic risk for many people with special needs. These include limited medical workups, uncooperative behavior, and difficulties in postoperative cares, etc. But Judging from several years experience of many contries, it appears that the incidence of mortalities for people with special needs in dental setting is minimal and the incidence of morbidity is limited. In the long run, the delivery of general anesthesia and deep sedation for people with special needs can be considered a very safe and successful procedure.

• Journal of Microbiology and Biotechnology
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• v.19 no.3
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• pp.217-228
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• 2009

Mobile genetic segments, or transposons, are also referred to as jumping genes as they can shift from one position in the genome to another, thus inducing a chromosomal mutation. According to the target site-specificity of the transposon during a transposition event, the result is either the insertion of a gene of interest at a specific chromosomal site, or the creation of knockout mutants. The former situation includes the integration of conjugative transposons via site-specific recombination, several transposons preferring a target site of a conserved AT-rich sequence, and Tn7 being site-specifically inserted at attTn7, the downstream of the essential glmS gene. The latter situation is exploited for random mutagenesis in many prokaryotes, including IS (insertion sequence) elements, mariner, Mu, Tn3 derivatives (Tn4430 and Tn917), Tn5, modified Tn7, Tn10, Tn552, and Ty1, enabling a variety of genetic manipulations. Randomly inserted transposons have been previously employed for a variety of applications such as genetic footprinting, gene transcriptional and translational fusion, signature-tagged mutagenesis (STM), DNA or cDNA sequencing, transposon site hybridization (TraSH), and scanning linker mutagenesis (SLM). Therefore, transposon-mediated genetic engineering is a valuable discipline for the study of bacterial physiology and pathogenesis in living hosts.

• Journal of Pharmaceutical Investigation
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• v.35 no.6
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• pp.445-451
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• 2005

As a selective ${\alpha}_{1A}-adrenoreceptor$ antagonist, tamsulosin has been used clinically for urinary obstructed patients with benign prostatic hyperplasia. The single and multi-layered pellets containing tamsulosin hydrochloride were prepared in an effort to control the drug release, avoiding dose-dependent side effects of tamsulosin hydrochloride upon oral administration. The drug release from multi-layered pellets was substantially controlled, compared with single layered pellets. The drug release from coated pellets with single or multi layer was affected by the nature of coating agent, the percentage of coating level and the presence of hydrophilic material in coating layer. In conclusion, the controlled release oral delivery system using multi-layered pellet is very useful for tamsulosin hydrochloride, resulting in improvement of patient compliance and therapeutic drug levels for a longer period of time.

• Journal of Pharmaceutical Investigation
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• v.35 no.3
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• pp.157-163
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• 2005

The pellets with multiple drug release system (MDRS) of Diltiazem. HCl which consist of immediate drug release layer, drug reservoir layer and controlled release rate membrane, were prepared by using CF-Coater. As main factors for more effective MDRS of Diltiazem. HCl, ethylcellulose was used for the controlling drug release rate, and diethylphthalate was used for plasticizer, respectively. In vitro evaluation study was performed by comparative dissolution test between our test MDRS and reference Diltiazem. HCl preparation. The physical tests were performed using FT-IR and SEM. In vivo evaluation was also performed by observing the behavior of a plasma drug concentration after oral administration. The bioavailability was determined by analyzing the blood sample after oral administration to healthy, male volunteers once a day. As a result, there were no significant differences in bioequivalence parameters $(AUC_{\infty},\;C_{max},\;t_{1/2})$ between two systems. It might be concluded that our MDRS of Diltiazem. HCl could be an alternative delivery system to reference drug preparation.

• Journal of Pharmaceutical Investigation
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• v.32 no.4
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• pp.327-330
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• 2002

Alginate based polymeric matrices were designed for controlled release and stabilization of cefaclor in gastrointestinal fluid. Cefaclor is known to be acid stable and subjected to be degraded at neutral and alkaline pHs. In order to achieve an effective release profile of cefaclor in gastrointestinal tract, a particular strategy in dosage form design should be required from the view point of maintaining its activity. The amphiphilic nature of cefaclor allowed its controlled release using ionic polymers based on ionic interaction between the drug and polymers. The thrust of this study was to develop a technique that delivers cefaclor keeping effective release rate in the intestinal tract. Considering the fast degradation of cefaclor in the intestinal fluid, the matrices were designed to release surplus amount of cefaclor. The alginate based matrices demonstrated increase in release rate in the simulated intestinal fluid, which was favorable to compensate the degraded portion of cefaclor. In addition, stabilization of cefaclor in the intestinal fluid was obtained by employing citric acid that provides an local acidic environment. The matrices might be valuably used for the development of an oral cefaclor dosage form.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.10 no.1
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• pp.9-14
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• 1980

The author studied on the effects of X-ray irradiation to the development of periodontal ligament in gestation rats. They were irradiated in their abdomen with 100, 200 and 300 rads respectively in one shot irradiation with deep radiation therapy equipment (MAXIMAR 250-Ⅲ), In 7th, 14th, 21th and 28th day after delivery, those new born rats were respectively sacrificed with ether anesthesia and removed of their mandibles. After removal, those mandibles were fixed in 10% neutral buffer formalin, decalcified with 5% trichloroacetic acid for 5 days and embedded with paraffine. Staining was performed with H-E, Van Gieson, Mallory azan, Bielshowsky-Gomori silver stain and Halmi's oxytalan fiber stain. The results were as follows: 1. Before tooth eruption, all the fiber: components in dental sac were almost always oriented near the outer enamel epithelial \layer. But in irradiated new born rats, those collagen fiber orientation was more irregular than those of control groups, and this phenomenon was more severe in proportion to the amount of irradiation in the gestation period. 2. Before tooth eruption, the connective tissue fibers in periodontal ligament were stained with lighter in the irradiated groups than those of control groups. Oxytalan fibers of irradiated groups were thin and splitting pattern of their fiber morphology to compare with those of control groups. 3. After tooth eruption, the periodontal ligament fibers of irradiated groups were oriented functionally and their morphology was thick, fine and heavy staining. Oxytalan fibers were revealed with oblique parallel arrangement in the periodontal ligament of irradiated groups.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.35 no.4
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• pp.248-252
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• 2009

Purpose: This retrospective study was performed to analyze the relationship between complications of the posterior mandibular single crowns and distance from the adjacent teeth to the implant. Subjects and Methods: Of the patients who presented Ewha Womans University Mokdong Hospital & Yonsei University Dental Hospital with missing of the posterior mandibular molar and restored with implant-supported 18 Single crowns between 1996 thru 2007, 115 patients had been followed after crown delivery. The subjects were divided into complication-followed group and a control without any problems. The distance from the most distal tooth to the implant were measured. The prosthetic & biologic complications were reviewed by the cantilever distance and analyzed by abutment type, age & gender statistically using SAS version 9.1 (SAS Inc., USA). Results and Conclusion The results were as follows; 1) The posterior mandibular single crown with cantilever showed higher incidence of follow-up complications upon logistic analysis (p<0.05). 2) The prosthetic and biologic complications are related with the cantilever distance with 2.1 odds ratio and 3.39 cut-off value of specificity & sensitivity by SPSS 12.0. 3) The complications are neither significant in abutment types nor age & gender.

• Archives of Pharmacal Research
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• v.27 no.1
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• pp.118-126
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• 2004

The aqueous extract of European mistletoe (Viscum album, L.) has been used in cancer therapy. The purified mistletoe lectins, main components of mistletoe, have demonstrated cytotoxic and immune-system-stimulating activities. Korean mistletoe (Viscum album L. coloratum), a subspecies of European mistletoe, has also been reported to possess anticancer and immunological activities. A galactose- and N-acetyl-D-galactosamine-specific lectin (Viscum album L. coloratum agglutinin, VCA) with Mr 60 kDa was isolated from Korean mistletoe. Mistletoe preparations have been given subcutaneously due to the low stability of lectin in the gastrointestinal (GI) tract. In the present study, we investigated the possibility of alginate/chitosan microcapsules as a tool for oral delivery of mistletoe lectin. In addition, our strategy has been to develop a system composed of stabilizing cores (granules), which contain mistletoe lectin, extract or powder, coated by a biodegradable polymer wall. Our results indicated that successful incorporation of VCA into alginate/chitosan microcapsules has been achieved and that the alginate/chitosan microcapsule protected the VCA from degradation at acidic pH values. And coating the VCA with polyacrylic polymers, Eudragit, produced outstanding results with ideal release profiles and only minimal losses of cytotoxicity after manufacturing step. The granules prepared with extract or whole plant produced the best results due to the stability in the extract or whole plant during manufacturing process.

• Science of Emotion and Sensibility
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• v.25 no.2
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• pp.79-86
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• 2022

With external air pollution forcing many people indoors, new methods of facilitating healthier indoor life are necessary. This study, therefore, investigates the effects of indoor oxygen concentration and respiration methods on biosignals and cognitive ability. The study included twenty healthy subjects who inhaled air through a mask from a gas delivery system. All subjects were asked to perform three types of breathing (nasal, oral, and oral breathing with high oxygenation) and respond to cognitive stimuli (rest close eye, rest open eye, 1-back and 2-back working memory tasks). The changes in cognitive load according to respiration were analyzed by measuring response time, accuracy, and biosignals to stimuli. The result showed that, in all three respirations, heart rate significantly increased with the increase in cognitive load. Also, in oral respiration, the airway respiration rate significantly increased according to the increase in cognitive load. The change appeared to compensate for insufficient oxygen supply in oral respiration during cognitive activity. Conversely, there was no significant change in airway respiration rate during oral respiration with a high concentration oxygen supply as in nasal respiration. This result suggests that a high concentration oxygen supply might play a role in compensating for insufficient oxygen concentration or inefficient oxygen inhalation, such as oral respiration. Based on the results of this study, a follow-up study is necessary to determine the impact of changes in the autonomic nervous system, such as stress and emotions, to find out more precise and comprehensive effects of oxygen concentration and breathing type.