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        검색결과 828

        581.
        2011.03 구독 인증기관 무료, 개인회원 유료
        Teeth develop via a reciprocal induction between the ectomesenchyme originating from the neural crest and the ectodermal epithelium. During complete formation of the tooth morphology and structure, many cells proliferate, differentiate, and can be replaced with other structures. Apoptosis is a type of genetically-controlled cell death and a biological process arising at the cellular level during development. To determine if apoptosis is an effective mechanism for eliminating cells during tooth development, this process was examined in the rat mandible including the developing molar teeth using the transferase-mediated dUTP-biotin nick labeling (TUNEL) method. The tooth germ of the mandibular first molar in the postnatal rat showed a variety of morphological appearances from the bell stage to the crown stage. Strong TUNEL-positive reactivity was observed in the ameloblasts and cells of the stellate reticulum. Odontoblasts near the prospective cusp area also showed a TUNEL positive reaction and several cells in the dental papilla, which are the forming pulp, were also stained intensively in this assay. Our results thus show that apoptosis may take place not only in epithelial-derived dental organs but also in the mesenchyme-derived dental papilla. Hence, apoptosis may be an essential biological process in tooth development.
        4,000원
        582.
        2011.03 구독 인증기관 무료, 개인회원 유료
        Ursolic acid is a triterpenoid compound present in many plants. This study examined the antimicrobial activity of ursolic acid against mutans streptococci (MS) isolated from the Korean population. The antimicrobial activity was evaluated by the minimum inhibitory concentration (MIC) and time kill curves of MS. The cytotoxicity of ursolic acid against KB cells was tested using an MTT assay. The MIC90 values of ursolic acid for Streptococcus mutans and Streptococcus sobrinus isolated from the Korean population were 2 μg/ml and 4 μg/ml, respectively. Ursolic acid had a bactericidal effect on S. mutans ATCC 25175 T and S. sobrinus ATCC 33478 T at > 2 × MIC (4 μg/ml) and 4 × MIC (8 μg/ml), respectively. Ursolic acid had no cytotoxic effect on KB cells at concentrations at which it exerted antimicrobial effects. The results suggest that ursolic acid can be used in the development of oral hygiene products for the prevention of dental caries.
        4,000원
        583.
        2010.12 구독 인증기관 무료, 개인회원 유료
        Angelica decursiva has been used in Korean traditional medicine as an antitussive, an analgesic, an antipyretic and a cough remedy. However, its anti-cancer properties have not yet been well defined. In our current study, we report the cytotoxic activity and the mechanism of cell death induced by ethanol extracts of Angelica decursiva (EEAD) against the human oral cancer cell line, KB. Treatment of KB cells with EEAD induced apoptotic cell death in both a dose- and time-dependent manner as determined by MTT assay and DNA fragmentation. However, no cytotoxic effects of EEAD against human normal oral keratinocytes (HNOK) were evident. By western blot analysis, we found that apoptosis in KB cells is associated with a decrease in procaspase-7 and -9. In addition, the activation of caspase-7 was detectable in living KB cells by fluorescence microscopy. These results suggest that EEAD exhibits anti-cancer activity in KB cells via apoptosis and thus has potential as an anticancer agent in future drug development strategies.
        4,000원
        584.
        2010.12 구독 인증기관 무료, 개인회원 유료
        A nine-month-old male Pekingese weighing 5.7 kg was admitted to the Veterinary Medical Center at Chungbuk National University with a history of acute nonambulatory tetraparesis after minor trauma. A diagnosis of atlantoaxial instability with a dens axis fracture was based on examination of survey spinal radiographs and was confirmed during surgery. A modified ventral fixation technique using cortical screws was used for stabilization of the atlantoaxial joint. Serial evaluation based on radiographic and neurologic assessment was performed eight weeks after surgery. Symptoms of tetraparesis disappeared gradually, and arthrodesis of the atlantoaxial joint using a ventral fixation technique has maintained stable fixation.
        4,000원
        585.
        2010.12 구독 인증기관 무료, 개인회원 유료
        Influenza virus infection is a zoonosis that results in high mortality in animals and humans. Several recent avian influenza outbreaks have posed a significant public health threat to humans because there have been many cases of direct interspecies transmission from birds to humans. Influenza virus infection causes acute respiratory failure, which is the main cause of death, while chronic influenza virus infection in the central nervous system results in neural dysfunction. Of particular interest, according to one report, a group of patients who recovered from influenza virus infection during pandemics showed neuropsychiatric disorders, including depression, schizophrenia, and Parkinsonism. Thus, study of the etiology of neuropsychiatric disorders caused by influenza virus infection is needed. In order to conduct necessary experiments, it is essential to reproduce neurological phenomena that are manifested by human patients who have recovered from influenza virus infection using laboratory animals. In this review, we will discuss some of the facts that should be considered when establishing an animal model for study of central nervous system responses to influenza virus infection using mice.
        4,000원
        586.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was to investigate the effects of upper and lower limb composing patterns of PNF(proprioceptive neuromuscular facilitation) on the static balance ability by 20 subjects for 6 weeks. This study was measured left one leg standing and right one leg standing with closed eyes on Good Balance system. These results led us to the conclusion that the mean speed of X, Y direction, COP(center of Pressure) velocity moment showed a statistical decrease when applying post-exercise. The above results from this study indicated that upper and lower limb composing patterns of PNF exercise has improved the static balance ability. As a result, this study showed that upper and lower limb composing patterns exercise improve the ability of balance in young adults. Based on this study, it may be applied to old people.
        4,000원
        587.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The purpose of this study was to determine the difference of the pinch strength according to testing posture(standing and sitting) and elbow flexion degree(0。, 45。, 90。and 135。). Forty normal young adults(male: 20, female: 20, mean age: 22.68±2.91 years) participated in this study. The methods of this study were categorized as follows: 1) One set of measurement was performed on four elbow flexion degrees(0。, 45。, 90。and 135。) in two testing postures(standing and sitting) and all subjects were measured for 3 sets testing procedures in every experimental sessions. 2) Pinch strength in various elbow flexion degree was measured after 2 min rest time, and then each test set was repeatedly performed with 5 min rest time to prevent fatigue of muscles involved in the elbow joint. The result was obtained as follow: 1) In standing posture, there was statistically significant difference at 0。and 45。, 0。and 90。, 0。and 135。, 45。and 90。, 45。and 135。, 90。and 135。. 2) In sitting posture, there was statistically significant difference at 0。and 45。, 0。and 90。, 0。and 135。, 45。and 90。, 45。and 135。, 90。and 135。. 3) Statistically, there was no significant difference between standing and sitting posture in same elbow flexion degree, however pinch strength in standing posture was higher than sitting posture.
        4,000원
        588.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The majority of strokes are caused by ischemia and result in brain tissue damage, leading to problems of the central nervous system including hemiparesis, dysfunction of language and consciousness, and dysfunction of perception. The purpose of this study was to investigate the effects of Poly(ADP-ribose) polymerase(PARP) on necrosis in neuronal cells that have undergone needle electrode electrical stimulation(NEES) prior to induction of ischemia. Ischemia was induced in male SD rats(body weight 300g) by occlusion of the common carotid artery for 5 min, after which the blood was reperfused. After induction of brain ischemia, NEES was applied to Zusanli(ST 36), at 12, 24 and 48 hours. Protein expression was investigated using immuno-reactive cells, which react to PARP antibodies in cerebral nerve cells, and Western blotting. The results were as follows: In the cerebral cortex, the number of PARP reactive cells after 24 hours significantly decreased(p<.05) in the NEES group compared to the GI group. PARP expression after 24 hours significantly decreased(p<.05) in the NEES group compared to the GI group. As a result, NEES showed the greatest effect on necrosis- related PARP immuno-reactive cells 24 hours after ischemia, indicating necrosis inhibition, blocking of neural cell death, and protection of neural cells. Based on the results of this study, NEES can be an effective method of treating dysfunction and improving function of neuronal cells in brain damage caused by ischemia.
        4,000원
        589.
        2010.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study is intended to examine the motor skill learning and treadmill exercise on motor performance and synaptic plasticity in the cerebellar injured rats by harmaline. Experiment groups were divided into four groups and assigned 15 rats to each group. GroupⅠ was a normal control group(induced by saline); GroupⅡ was a experimental control group(cerebellar injured by harmaline); GroupⅢ was a group of motor skill learning after cerebellar injured by harmaline; GroupⅣ was a group of treadmill exercise after cerebellar injured by harmaline. In motor performance test, the outcome of groupⅡ was significantly lower than the groupⅢ, Ⅳ(especially groupⅢ)(p<.001). In histological finding, the experimental groups were destroy of dendrities and nucleus of cerebellar neurons. GroupⅢ, Ⅳ were decreased in degeneration of cerebellar neurons(especially groupⅢ). In immunohistochemistric response of synaptophysin in cerebellar cortex, experimental groups were decreased than groupⅠ. GroupⅢ's expression of synaptophysin was more increased than groupⅡ, Ⅳ. In electron microscopy finding, the experimental groups were degenerated of Purkinje cell. These result suggest that improved motor performance by motor skill learning after harmaline induced is associated with dynamically altered expression of synaptophysin in cerebellar cortex and that is related with synaptic plasticity.
        4,000원
        591.
        2010.05 구독 인증기관·개인회원 무료
        Attacin is a well-studied glycine-rich antibacterial protein in insect immune response, which has limitary antibacterial effect to some Gram-negative bacteria. A cDNA encoding the attacin gene was screened and isolated from the immunized larvae of the swallowtail butterfly, Papilio xuthus. The complete P. xuthus attacin cDNA is 949 nucleotides encoding a 250 amino acid precursor that contains a putative 18-residue signal peptide, a common 42-residue propeptide sequence and a presumed 190-residue mature protein with a theoretical mass of 19904.01 and a pI of 9.13. The putative mature protein of P. xuthus attacin showed 48%~52% and 24%~30% identity in amino acid sequences with that of lepidopteran and dipteran insects, respectively. The attacin transcript was induced at significant level after injection with bacterial lipopolysaccharide (LPS). Recombinant attacin was highly expressed in E. coli BL21 (DE3) cells by fusing with an N-terminal S-tag/thrombin cleavage site configuration protein to avoid the cell death during induction. The expressed fusion protein was purified by Ni-NTA immobilized metal affinity chromatography (IMAC). After desalting and cleavage with thrombin, the recombinant attacin was released and showed considerably antibacterial activity against Gram-negative bacteria, E. coli ML 35. Our results proved that this protein family with a potent antibacterial activity may play a role in the immune response of butterflies.
        592.
        2010.05 구독 인증기관·개인회원 무료
        The phylogenetic relationships among true butterfly families (superfamily Papilionoidea) have been a matter of substantial controversy, and that debate has led to several competing hypotheses. Two of the most compelling of those hypotheses involve the relationships of (Nymphalidae + Lycaenidae) + (Pieridae + Papilionidae) and (((Nymphalidae + Lycaenidae) + Pieridae) + Papilionidae). In this study, approximately 3,500 nucleotide sequences from cytochrome oxidase subunit I (COI), 16S ribosomal RNA (16S rRNA), and elongation factor-1 alpha (EF-1α) were sequenced from 83 species belonging to four true butterfly families, along with those of eight outgroup species belonging to the skipper family (superfamily Hesperioidea). These sequences were subjected to phylogenetic reconstruction via Bayesian Inference (BI), Maximum Likelihood (ML), and Maximum Parsimony (MP) algorithms. All phylogenetic analyses among the four true butterfly families strongly indicated a sister relationship between the Nymphalidae and Lycaenidae on one hand, and relatively strongly indicated a sister relationship between the Pieridae and Papilionidae on another hand, thus supporting the hypothesis: (Nymphalidae + Lycaenidae) + (Pieridae + Papilionidae).
        593.
        2010.05 구독 인증기관·개인회원 무료
        The bumblebee, Bombus ignitus (Hymenoptera: Apidae), is a valuable natural resource that is one of the most notably utilized for greenhouse pollination in Korea. In order to understand the nature of genetic relationships, gene flow, and population structure of the species we sequenced a partial COI gene of mitochondrial DNA (mtDNA) corresponding to “animal barcode” region and the complete internal transcribed spacer 2 (ITS2) of the nuclear ribosomal DNA (nrDNA) collected from Korean localities. Although the 658-bp long mtDNA sequence provided only six haplotypes with the maximum sequence divergence of 0.61% (4 bp), the ITS sequences provided 84 sequence types with the maximum sequence divergence of 1.02% (21 sites), confirming better applicability of the ITS sequences to the study of intraspecific variation. The complete ITS2 sequences of B. ignitus were shown to be longest among known insects, ranging in size from 2,034 bp ~ 2,052 bp, harboring two duplicated repeats. Overall, a very high per generation migration ratio, a very low level of genetic fixation, and no discernable hierarchical population/ population group were noted to exist among populations of B. ignitus on the basis of both molecules, thus suggesting that the B. ignitus populations on the Korean peninsula are panmictic, which is consistent with our understanding of the dispersal capability of the species
        594.
        2010.05 구독 인증기관·개인회원 무료
        In an effort to gain a better understanding of the nature of the population genetic structure of the pest insect, Spodoptera litura (Lepidoptera: Noctuidae), tobacco cutworms were collected from six Korean and five Chinese localities and their mitochondrial A+T-rich region and nuclear internal transcribed spacer 2 (ITS2) regions were cloned and sequenced. A total of 106 A+T-rich region haplotypes and 92 ITS2 sequence types were obtained from 158 individuals. Compared to the preliminary mitochondrial COI gene sequence data that provided all identical sequence types in all samples, the A+T-rich region and nuclear ITS2 are highly variable. Overall, a low level of genetic fixation in the A+T-rich region (FST = 0 ~ 0.02965) and nuclear ITS2 (FST = 0 ~ 0.34491), and no discernable isolated population was noted to exist among most S. litura populations. The presence of a majority of within-population variations, rather than variations among populations or between China and Korea, indicates that the S. litura populations are composed of heterogeneous individuals. The fixation index at hierarchical level of among regions shows no significance, suggesting that the S. litura populations in both Korea and China are profoundly interrelated with one another. This finding is in accord with the current knowledge that S. litura has sufficient flight capacity for dispersal.
        595.
        2010.05 구독 인증기관·개인회원 무료
        Two complete mitochondrial genomes (mitogenomes) of the endangered, lycaenid butterflies, Spindasis takanonis and Protantigius superans (Lepidoptera: Lycaenidae), were sequenced. Each 15,349 bp and 15,248 bp-long genome contained both the lepidopteran specific gene arrangement that differ from the most common arrangement of insects by the movement of tRNAMet to a position 5’-upstream of tRNAIle. Neither of the species have typical COI start codon. Instead, the CGA (arginine) sequence that is commonly present in all other lepidopterans was also found in both lycaenids. The possible binding site for the transcription termination peptide, TACTA sequence, also was well retained in both species. The high A+T-content, which is a characteristic of insect mitogenomes was well reflected in the genomes in the form of higher frequency of codons with A/T nucleotides, severe A/T bias in 3rd codon position, and extremely high A/T content in the A+T-rich region. The 19 bp-long poly-T stretch and the downstream conserved motif ATAG, which were suggested previously to function as a structural signal for minor-strand mtDNA replication, was also well conserved in the A+T-rich region of both lycaenids. Phylogenetic analysis among lepidopteran superfamilies supported the relationships of either (((((Bombycoidea + Geometroidea) + Noctuoidea) + Papilionoidea) + Pyraloidea) + Tortricoidea) by concatenated amino acid sequence or (((((Bombycoidea + Geometroidea) + Noctuoidea) + Pyraloidea) + Papilionoidea) + Tortricoidea) by concatenated nucleotide sequences of 1st and 2nd codon positions of 13 protein-coding genes, two rRNA genes, and 22 tRNA genes, revealing fluctuating positions of Papilionoidea and Pyraloidea between the two data sets.
        596.
        2010.03 구독 인증기관 무료, 개인회원 유료
        Prostatic calculi are common finding in radiographic examination, however, the true incidence and the clinical significance are not clearly known. We investigated the prevalence of prostatic calculi and the relationship between prostatic calcification and urolithiasis. From a database, 305 consecutive subjects older than 30 years of age who had undergone regular health checks in our hospital from January 2007 to July 2009 were enrolled in this study. Prostatic calculi and urinary stones were confirmed by non-enhanced CT. According to the presence of prostatic calculi, they were divided into two groups and the relationship with urolithiasis was determined using statistical analysis. Among 305 male subjects, prostatic calculi were found in 97 (31.9%), which revealed a linear trend with aging (r=0.928, p=0.023), while asymptomatic upper urinary tract stones were found in 45 subjects (14.9%). A significant difference was observed in mean age (p<0.001), however, no difference was observed in prevalence of diabetes mellitus (DM), hypertension (HT), and body mass index (BMI). In the prostatic calculi group, 24 (24.7%) subjects had previously unknown urolithiasis, while only 21 subjects (10.1%) in the non-prostatic calculi group had urinary stones. The prevalence of urolithiasis was significantly higher in men with prostatic calcification than in those without prostatic calcification (OR=2.92, 95% CI: 1.53-5.58, p=0.001). No significant differences in serum chemistry were observed between the two groups. Among the 45 patients with urolithiasis, no significant differences were observed in the mean stone size according to the presence of prostatic calcification. Our data showed that prostatic calcification was prevalent up to approximately 31.9% and was frequently combined with upper urinary tract stones. These results indicate that evaluation for urolithiasis might be needed in patients with incidentally detected prostatic calcification.
        4,000원
        597.
        2009.12 구독 인증기관 무료, 개인회원 유료
        There have been significant changes to family values and the types of families have diversi-fied. This phenomenon gave way to the rise of the lower fertility and aging society, and could also cause disorganization or crisis of family in the future. It has now become necessary to build family-friendly values through the new education envi-ronment, Web 2.0. Social Network Service (SNS), the main idea of this study, represents one type of the new environment. It is a vital and well-matched concept with family-friendly val-ues. The paradigm shift in education has features such as interaction, relationship and com-munication. The purpose of this study was to suggest feasibility of Social Network Service for forming family-friendly values. To verify the feasibility, four family websites in Korea were examined with the research method of SWOT Analysis. To find strategies, SWOT factors were identified as follows; 1) Strength factors of Social Network Service for family-friendly values formation: free ser-vice, diverse functions, and global interactivity through language service. 2) Weakness factors: unstable, virtual disorder resulting from too many functions, and lack of user directedness. 3) Opportunity factors: increasing needs of family value education and improvement to mul-ticultural society. 4) Threat factors: digital literacy divide between old and new generation and decreasing time to communicate with family. In this study, the following seven strategies were extracted through SWOT analysis: 1) Practice educational paradigm shift: Web 2.0 2) Change educational settings in multicultural society 3) Challenge media convergence 4) Represent ability of ubiquitous learning 5) Promote interactivity across all age groups, taking into account life cycle 6) Present user-directed interfaces 7) Conduct instructional contents or curriculum with blended learning at K-12 Keywords: Family friendly values, Web 2.0, Learning 2.0, SWOT Analysis
        4,600원
        599.
        2009.10 구독 인증기관·개인회원 무료
        Inflammatory bowel disease (IBD) is a group of chronic disorders of unknown etiology characterized by inflammation of the gastrointestinal tract. Recent data showed that the development of IBD is associated with the interplay of genetic, bacterial, and environmental factors and dysregulation of the intestinal immune system. We investigated how the gut cells were repaired after injury in Drosophila melanogaster. In this study we made D. melanogaster intestine damage model by oral feeding with variety IBD inducer such as pathogenic bacteria Serratia marcescens, Dextran Sulfate Sodium (DSS) and bleomycin, because its function is very similar with human, even though D. melanogaster has relatively simple organism. We repeated oral feeding with variety IBD inducer and got the survival rate and 50% lethal dose (LD50). After feeding with IBD inducer, we investigated the change of the intestinal stem cells, innate immune-related gene expression, and apoptosis in D. melanogaster gut. We examined the Delta, stem cell marker, staining image in the gut after feeding with DSS and S. marcescens with LD50 concentration. The Delta positive cells greatly increased in gut cells damaged by DSS or S. marcescens. This result supports the idea that intestinal gut stem cells are increased after gut cell damage and play very important role in damaged cell repair. Expression level of antimicrobial peptides was dramatically up-regulation after gut damage. As a result of TUNEL (terminal deoxynucleotidyl transferase mediated X-dUTP nick end labeling) assay, we confirmed that cell death by apoptosis was very increased in DSS feeding flies. Accordingly, we suggest that D. melanogaster is a proper IBD model organism to study how intestine damage can be repaired.
        600.
        2009.10 구독 인증기관·개인회원 무료
        The Nilaparvata lugesn(BPH) and Laodelphax striatellus(SBPH) are major insect pests of rice in Korea. These BPHs migrate from China to Korea, but we have not exactly known about the route of long-distance migration of them. Molecular markers including microsatellite will be critical to asses gene flow in relation to geographical distance. In our work several microsatellite markers were developed for basic population genetic analysis of BPH and SBPH. Among each 21 microsatellite markers in BPH and SBPH, we could select 6 markers for BPH and 2 markers for SBPH as putative markers for analysis of population genetics. Others are further investigated for the possibility as markers. Development of polymorphic microsatellite loci are final stage of our work. But for good microsatellite markers to population genetics, we should do more experiments. Our work for development of microsatellites should facilitate the study of future population genetics of BPH and SBPH, and eventually elucidate the route of BPH and SBPH migration to Korea.