• Restorative Dentistry and Endodontics
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• v.35 no.3
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• pp.211-221
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• 2010

Proteoglycan is highly hydrophilic and negatively charged which enable them attract the water. The objective of study was to investigate the effects of Proteoglycan on microtensile bond strength of dentin adhesives and on architecture of dentin collagen matrix of acid etched dentin by removing the chondroitin sulphate attached on Proteoglycan. A flat dentin surface in mid-coronal portion of tooth was prepared. After acid etching, half of the specimens were immersed in 0.1 U/mL chondroitinase ABC (C-ABC) for 48 h at $37^{\circ}C$, while the other half were stored in distilled water. Specimens were bonded with the dentin adhesive using three different bonding techniques (wet, dry and re-wet) followed by microtensile bond strength test. SEM examination was done with debonded specimen, resin-dentin interface and acid-etched dentin surface with/without C-ABC treatment. For the subgroups using wet-bonding or dry-bonding technique, microtensile bond strength showed no significant difference after C-ABC treatment (p > 0.05). Nevertheless, the subgroup using rewetting technique after air dry in the Single Bond 2 group demonstrated a significant decrease of microtensile bond strength after C-ABC treatment. Collagen architecture is loosely packed and some fibrils are aggregated together and relatively collapsed compared with normal acid-etched wet dentin after C-ABC treatment. Further studies are necessary for the contribution to the collagen architecture of noncollagenous protein under the various clinical situations and several dentin conditioners and are also needed about long-term effect on bond strength of dentin adhesive.

• Korean Journal of Cognitive Science
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• v.28 no.1
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• pp.1-26
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• 2017

This study investigated the cortical generators of P300 in college students with schizotypal traits by using an auditory oddball paradigm, event-related potentials (ERPs) and standardized low resolution brain electromagnetic tomography (sLORETA) model. We also investigated the relationship between the current density of P300 and the clinical symptoms of schizophrenia. Based on the scores of Schizotypal Personality Questionnaire(SPQ), schizotypal trait (n=37) and control (n=42) groups were selected. For the measurement of P300, an auditory oddball paradigm, in which frequent standard tones (1000Hz) and rare target tones (1500Hz) were presented randomly, was used. Participants were required to count the number of the target tones during the task and report this at the end of the experiment. The two groups did not differ significantly in the accuracy of the oddball task. The schizotypal trait group showed significantly smaller P300 amplitudes than control group. In terms of source localization, both groups showed the P300 current density over bilateral frontal, parietal, temporal and occipital lobes. However, the schizotypal trait group showed significantly reduced activations in the left superior temporal gyrus and the right middle temporal gyrus, but increased activations in both left inferior frontal gyrus and right superior frontal gyrus compared to the control group. Furthermore, a negative correlation between the current density of the right superior frontal gyrus and SPQ disorganization score was found in the schizotypal trait group. These findings indicate that the individuals with schizotypal traits have dysfunctions of frontal and temporal areas, which are known to be the source of P300, as observed in patients with schizophrenia. In addition, the present results indicate that the disorganization score, rather than total score, of the SPQ is useful in predicting the risk of future schizophrenia.

• The Journal of the Korea Contents Association
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• v.8 no.11
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• pp.210-216
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• 2008

In this study, image comparisons were carried out using a MRI contrast medium which was derived by mixing a polyaminocarboxylic ligand and a gadolinium (III) transition metal which is paramagnetic and has good neutron absorbing capabilities with Gd-DTPA which is currently being used widely in the clinical setting. By using a 1.0T (Harmony, SIEMENS) MR equipment, phantoms of which 100cc of saline was diluted with a diethylenetriaminetriacetic acid derivative and Gd-DTPA were imaged. The amount of diethylenetriaminetriacetic acid and Gd-DTPA which was diluted into the 100cc of saline was 0.05mmol/L, 0.1mmol/L, 0.15mmol/L, 0.2mmol/L, 0.3mmol/L, 0.5mmol/L, 1.0mmol/L, 2.0mmol/L, 3.0mmol/L and 4.9mmol/L respectively. Head coils were used and while fixing the SE pulse sequence and image variable (as TE is 14ms, 1NEX with a 256x201 matrix), the signal intensity and simple contrast ratios according to changing concentrations and TR were compared with various TR at 300ms, 400ms, 500ms, 600ms, 700ms, 800ms, 900ms, 1000ms, 1200ms, 1400ms and 1600ms. According to the comparison results of the signal intensity of the image based on changes in contrast medium concentrations and TR, the differences in signal intensity between the two contrast mediums were found to be small at $1.0{\sim}2.0mmol/L$ when the highest signal intensity was achieved. However, at concentrations of 1.0mmol/L or less, the signal intensity was markedly higher in the Diethylenetriaminetriacetic acid derivative than in the Gd-DTPA complex. It was also found that the differences in the signal intensities demonstrated by the concentrations of the contrast mediums were affected by the TR. Accordingly, the efficacy of the Diethylenetriaminetriacetic acid derivative was shown to be better than the Gd-DTPA and also possible to get the optimum image quality by the use of an appropriate TR with appropriate concentrations of contrast medium.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.186-190
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• 2005

Purpose : The purpose of this study was to evaluate the responses and toxicities of risk-adapted chemotherapy in pediatric intracranial germ cell tumors(IC-GCT). Methods : Fourteen patients who were diagnosed as IC-GCT from October 2002 to December 2003 received chemotherapy as an initial treatment modality. The low risk(LR) group was defined as follows : Pure germinoma and normal AFP level. Beta-hCG level 50 mIU/mL or less. The others belonged to the high risk(HR) group. Chemotherapy was composed of cisplatin, cyclophosphamide, etoposide and vincristine. Double doses of cisplatin and cyclophosphamide was used in HR patients. Results : Pathologic confirmation was done in all but one. Median age at diagnosis was 11.6 yr (1.2-18.7 yr), and nine patients belonged to the HR group. Tumor markers were normalized after chemotherapy in all patients whose tumor markers had been elevated. Four LR patients(80 percent) and seven HR patients(77.8 percent) showed complete response(CR) at the end of chemotherapy. An additional two of the three patients with partial response(PR) achieved CR after radiation therapy (RT), and the remaining one relapsed before RT. Four LR and all HR patients experienced infectious episodes that required hospitalization. Four of the nine HR patients(44.4 percent) suffered from tinnitus, three of whom developed sensorineural hearing loss. All but one are surviving, event-free, with a median follow-up of 13.9 mo(8.1-22.3 mo). Conclusion : Risk-adapted cisplatin-based chemotherapy was effective even in HR patients, but regimen modification seems to be necessary to avoid an unacceptably high toxicity rate.

• Clinical and Experimental Pediatrics
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• v.48 no.2
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• pp.178-185
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• 2005

Purpose : The purpose of this study was to evaluate the outcome of children with juvenile myelomonocytic leukemia(JMML) treated with allogeneic hematopoietic stem cell transplantation(allo-HSCT). Methods : Eleven JMML patients aged 8-39 months underwent allo-HSCT. The sources of grafts were unrelated donors(n=7), HLA-matched siblings(n=3) and an HLA 1-antigen mismatched familial donor. All patients had received chemotherapy ${\pm}13$-cis-retinoic acid(CRA) before transplant, and CRA was used, posttransplant, in six patients. Results : Only three patients were in complete remission(CR) at the time of transplantation. Initial chimeric status revealed complete donor chimerism(CC) in five patients, mixed chimerism(MC) in five and autologous recovery(AR) in one. One patient with MC having persistent splenomegaly eventually turned to CC and CR after rapid tapering of cyclosporine, combined with daily use of CRA. An AR case relapsed shortly after transplant but was rescued with second, unrelated cord blood transplantation. Ultimately, six patients are alive, event-free, with a median follow-up of 15.5 months posttransplant. All three deaths occurred in patients who failed to achieve CC, leading to disease progression. Conclusion : We suggest that graft-versus-leukemia effect play an important role and CRA a possible role in posttransplant leukemic involution in JMML. In patients whose leukemic burden is still high with MC after transplant, early tapering of immunosuppressants and introduction of CRA might provide a chance of a cure for some patients.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1534-1539
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• 2002

Purpose : This study was designed to exclude radiation in advanced(stage 3, 4) Wilms tumor (WT) by increasing the chance of complete surgical removal with preceding neoadjuvant chemotherapy, thereby reducing the incidence of late effects. Methods : Between December 1998 and July 2002, we conducted neoadjuvant chemotherapy after needle aspiration biopsy on patients who had advanced WT. If needle biopsy was accessible, we conducted neoadjuvant chemotherapy(vincristine, adriamycin, dactinomycin) for 12 weeks and then performed surgical removal, excluded radiation therapy and conducted postoperative chemotherapy (vincristine, dactinomycin${\pm}$adriamycin). In other cases, we firstly conducted the operation and then performed radiation and postoperative chemotherapy. Results : Of the 17 patients diagnosed as WT, 12 patients had an advanced stage of disease. In two of the 12 patients, initial surgical removal was conducted. The median age of patients was 21 months(5-103 months). Of the 10 the patients who received neoadjuvant chemotherapy, eight patients were stage 1, one patient was stage 2, and the other was stage 3 at operation. In nine patients except one with stage 3 disease, we could perform complete surgical resection and therefore could omit radiation. In four cases we could also exclude adriamycin after operation. All but one patient was alive, disease-free, for a median follow-up of 21 months(9-43 months). Conclusion : After neoadjuvant chemotherapy, we could increase the chance of complete tumor resection, exclude radiation and decrease the intensity of postoperative chemotherapy in selected cases. Long term follow-up is needed to determine whether our method would significantly decrease late effects.

• Clinical and Experimental Pediatrics
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• v.45 no.11
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• pp.1403-1410
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• 2002

Purpose : In previous studies, various risk factors for recurrent febrile seizures have been identified. But none of these risk factors alone could sufficiently discriminate children at high or low risk for recurrent seizures. Therefore, we tried to identify patients at high risk of recurrent febrile seizures by combining risk factors. Methods : Two hundred and four children who had been admitted to our hospital from March, 1997 to July, 1999 with their first febrile seizures were enrolled in our study, and followed up over 2 years. We investigated the recurrence rate according to variables such as sex, age at first febrile seizure, family history of febrile seizures or epilepsy, type of the first seizure, neurologic abnormality and EEG abnormality. Results : Family history of febrile seizures and age at first febrile seizure(<12 months) were significant independent risk factors for recurrent febrile seizures. With these two combined factors, four groups were allocated and the recurrence rate by each group was designated as follows: group with no family history of febrile seizures and age at first febrile seizure ${\geq}12$ months (no risk factor), 43.8%; the group with no family history and age <12 months(one risk factor), 61.7%; group with family history and age ${\geq}12$ months(one risk factor), 64.5%; group with family history and age <12 months(two risk factors), 90.4%. Conclusion : A correlation between numbers of risk factors and recurrence rate was present and the children with a family history of febrile seizures and a young age at onset(<12 months) were regarded as a high risk group of recurrence.

• Clinical and Experimental Pediatrics
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• v.45 no.11
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• pp.1340-1345
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• 2002

Purpose : We studied the prevalence of snoring and its association with diseases, obesity and environmental factors, as well as sleep disturbance arising from snoring, in school-aged children. Methods : The survey was performed by a special questionnaire on 1,707 children at elementary schools from 1 to 30 July 2001 in Gwangju City. The prevalence of snoring, associated factors, and sleep disturbance were evaluated. Results : 266(16.5%) of the children snored at least once a week. 73(4.3%) of the children snored almost every day. Regarding the associated factors of snoring : There was a statistically significant difference between snoring and nonsnoring groups due to gender, obesity, sinusitis, tonsillar hypertrophy, bronchial asthma and allergic rhinitis. Of them, male gender, tonsillar hypertrophy, and obesity were significant risk factors for development of snoring. Especially, the odds ratio increased to 1.048(CI, 1.004-1.659), 1.748(CI, 1.175-2.599), and 2.266(CI, 1.300-3.950) in children with an obesity index of 20-29%, 30-49%, ${\geq}50%$, respectively. There was a statistically significant association of snoring with decreased sleep duration, sleep talking, and drowsiness during the day as a result of sleep disturbance. Conclusion : 16.5% of school-aged children snored at least once a week. The association of snoring with tonsillar hypertrophy, obesity and gender as risk factors was demonstrated in this study.

• Clinical and Experimental Pediatrics
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• v.45 no.11
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• pp.1332-1339
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• 2002

Purpose : Through a survey undertaken among doctors practicing pediatric patients in primary medical facilities on nutrition during infancy, the present study was done to determine whether these doctors were giving appropriate advice on infant nutrition. Methods : We visited pediatric specialists(group one) and non-pediatric specialists or general practitioners(group two) who were practicing in Daegu to ask them to fill out a questionaire on infant nutrition. Results : When 10 points were given to each question for a total of 100 points, the results of the evaluation showed that the score in group one was $73.0{\pm}15.8$ points and $45.1{\pm}18.4$ points in group two, showing a significant difference. No statistical difference was seen in the scores between non-pediatric specialists and general practitioners. Each answer to each question on the feeding period of breast milk, on loose stools during breast milk feeding, methods to deal with jaundice during breast milk feeding, choice of commercial baby food, criteria on directing soy milk, and criteria of guiding infant cereal was different between group one and two. Conclusion : The results of the present investigation showed that specialists in other fields or general practitioners were giving inappropriate advice on nutrition during the infant stage compared with pediatric specialists; thus, we need to confirm methods to prevent inappropriate consultations by specialists of other fields, together with continued education of pediatric specialists.

• Clinical and Experimental Pediatrics
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• v.45 no.12
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• pp.1512-1518
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• 2002

Purpose : Twins have a higher mortality and morbidity than singletons. Co-twin with one fetal death is particularly at risk. We investigated the neonatal outcome of live co-twins when one fetus had died after the 20th gestational week, and associated risk factors. Methods : A retrospective study was performed in fifteen cases of twin pregnancy with single intrauterine fetal deaths after the 20th gestational week during the period from January 1996 to December 2000 at Chonnam University Hospital. Results : Gestational age was $33.7{\pm}3.2weeks$, birth weight was $1,992{\pm}592g$. Interval between one fetal death being detected and the delivery of a live co-twin was $32.4{\pm}29.5days$. There were 11 cases(73.3%) of premature babies less than 37 gestational weeks. Main causes of preterm delivery were preterm labor and premature rupture of membranes. Hematologic findings suggesting disseminated intravascular coagulopathy(DIC) were not found in all mothers before delivery, and was not associated with DIC and encephalomalacia of the live co-twin. Perinatal outcome of fifteen live co-twins was as follows : six were normal(40%), three were DIC(20.0%), three were encephalomalacia(20.0%), one suffered intrauterine growth retardation, there was one case of twin to twin transfusion syndrome, and one of congenital heart disease(atrial septal defect with pulmonary stenosis). The occurrence of DIC and encephalomalacia in live co-twins was not related to placental chorionicity, birth weight, gestational week, and the interval between the detection one fetal death and the delivery of a live co-twin. Conclusion : We could not find any maternal hematologic problems in twin pregnancies complicated by one fetal death. Twenty percent of live co-twins showed DIC and encephalomalacia. However, its associated risk factors were not found. We need to investigate more closely the cases of live co-twins with one intrauterine fetal death.