• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.445-456
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• 2009

Statement of problem: Many studies have been conducted to improve the primary stability of implants by providing bioactive surfaces via surface treatments. Increase of surface roughness may increase osteoblast activity and promote stronger bonding between bone and implant surface and it has been reported that bioactive surface or titanium can be obtained through alkali and heat treatment. Purpose: The purpose of this study was to evaluate the stability of alkali and heat treated implants via histomorphometric analysis. Material and methods: Specimens were divided into three groups; group 1 was the control group with machined surface, the other groups were treated for 24 hours in 5 M NaOH solution and heat treated for 1 hour at $600^{\circ}C$ in the atmosphere (group 2) and vacuum (group 3) conditions respectively. Surface characteristics were analyzed and fixtures were implanted into rabbits. The specimens were histologically and histomorphometrically compared according to healing periods and change in bone composition were analyzed with EPMA (Electron Probe Micro Analyzer). Results: 1. Groups treated with alkali and heat showed increase of oxidization layer and Na ions. Groups 2 which was heat treated in atmosphere showed significant increase of surface roughness (P<.05). 2. Histomorphometric analysis showed significant increase in BIC (bone to implant contact) according to increase in healing period and there was significant increases in groups 2 and 3 (P<.05). 3. BA(bone area) ratio showed similar results as contact ratio, but according to statistical analysis there was significant increase according to increase in healing period in group 2 only (P<.05). 4. EPMA analysis revealed no difference in gradation of bone composition of K, P, Ca, Ti in surrounding bone of implants according to healing periods but groups 2 and 3 showed increase of Ca and P in the initial stages. Conclusion: From the results above, it can be considered that alkali and heat treated implants in the atmosphere have advantages in osseointegration in early stages and may decrease the time interval between implantation and functional adaptation.

• Sleep Medicine and Psychophysiology
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• v.6 no.1
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• pp.52-60
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• 1999

Objectives: With the object of finding the appropriate conditions and algorithms for dimensional analysis of human EEG, we calculated correlation dimensions in the various condition of sampling rate and data aquisition time and improved the computation algorithm by taking advantage of bit operation instead of log operation. Methods: EEG signals from 13 scalp lead of a man were digitized with A-D converter under the condition of 12 bit resolution and 1000 Hertz of sampling rate during 32 seconds. From the original data, we made 15 time series data which have different sampling rate of 62.5, 125, 250, 500, 1000 hertz and data acqusition time of 10, 20, 30 second, respectively. New algorithm to shorten the calculation time using bit operation and the Least Trimmed Squares(LTS) estimator to get the optimal slope was applied to these data. Results: The values of the correlation dimension showed the increasing pattern as the data acquisition time becomes longer. The data with sampling rate of 62.5 Hz showed the highest value of correlation dimension regardless of sampling time but the correlation dimension at other sampling rates revealed similar values. The computation with bit operation instead of log operation had a statistically significant effect of shortening of calculation time and LTS method estimated more stably the slope of correlation dimension than the Least Squares estimator. Conclusion: The bit operation and LTS methods were successfully utilized to time-saving and efficient calculation of correlation dimension. In addition, time series of 20-sec length with sampling rate of 125 Hz was adequate to estimate the dimensional complexity of human EEG.

• Journal of Yeungnam Medical Science
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• v.2 no.1
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• pp.103-111
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• 1985

Childhood epilepsy which has high prevalence rate and inception rate is one of the commonest problem encountered in pediatrician. In contrast with epilepsy of adult, in childhood epilepsy, more variable and varying manifestations are found because the factors of age, growth and development exert their influences in the manifestations and the courses of childhood epilepsy. Moreover epileptic children have associated problems such as physical and mental handicaps, psychologicaldisorders and learning disability. For these reasons pediatrician who deals with epileptic children experiences difficulties in making diagnosis and managing them. In order to improve understanding and management of childhood epilepsy, authors reviewed 103 cases of epileptic patients seen at pediatric department of Yeungnam University Hospital retrospectively. The patients were classified according to the type of epileptic seizure. Suspected causes of epilepsy, associated conditions of epileptic patients, age incidence and the findings of brain CT were reviewed. Large numbers of epileptic patients (61.2%) developed their first seizures under the age of 5. The most frequent type of epileptic seizure was generalized ionic-clonic, tonic, clonic seizure (49.5%), followed by simple partial seizure with secondary generalization (17.5%), simple partial seizure (7.8%), a typical absence (5.8%) and unclassified seizure (5.8%). In 83.5% of patients, we could not find specific cause of it, but in 16.5% of cases, history of neonatal hypoxia (4.9%), meningitis (3.9%), prematurity (1.9%), small for gestational age (1.0%), CO poisoning (1.0%), encephalopathy (1.0%), DPT vaccination (1.0%), cerebrovascular accident (1.0%) and neonatal jaundice (1.0%) were found, 30 cases of patients had associated diseases such as mental retardation, hyperactivity, delayed motor milestones or their combinations. The major abnormal findings of brain CT performed in 42 cases were cortical atrophy, cerebral infarction, hydrocephalus and brain swelling. This review stressed better designed classification of epilepsy is needed and with promotion of medical care, prevention of epilepsy is possible in some cases. Also it is stressed that childhood epilepsy requires multidisplinary therapy and brain CT is helpful in the evaluation of epilepsy with limitation in therapeutic aspects.

• Clinical and Experimental Reproductive Medicine
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• v.35 no.2
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• pp.143-153
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• 2008

Objective: To investigate the effects of aromatase inhibitor on reproductive hormone profiles and evaluate it's ovulation inducing capability in anovulatory infertile women. Methods: We quantified the blood levels of reproductive hormones from 30 healthy normal cycling women in natural cycle (control) and letrozole medicated cycle (study). LH, FSH, estradiol, testosterone, DHEA-S were quantified on third, 11th, 21th day in both cycles, and on 21th day, progesterone was added. Sixth anovulatory infertile women received either letrozole or clomiphene citrate for ovulation induction (n=30 in each groups). We compared the clinical parameters such as ovulation rate, pregnancy rate, the day of LH surge, number of follicles and endometrial thickness, cervical mucus amount, spinnbarkeit, mean diameter of follicles on the day of LH surge. Results: Letrozole had no effect on the LH, FSH, estradiol, DHEA-S secretion but there were significant increase in testosterone level on day 11 and progesterone level on day 21 in letrozole medicated cycle compared than control cycle ($0.40{\pm}0.16$ vs $0.28{\pm}0.11\;ng/ml$, p=0.002, $18.18{\pm}13.07$ vs $8.38{\pm}7.64\;ng/ml$, p=0.001, respectively). In comparison between letrozole and clomiphene groups, there were no significant difference in ovulation rate, pregnancy rate, number of mature follicle, mean diameter of follicles, but showed earlier LH surge, thicker endometrium, more cervical mucus, and higher spinnbarkeit in letrozole group ($12.12{\pm}2.46$ vs $14.52{\pm}3.18$ days, p=0.006, $10.48{\pm}1.23$ vs $8.52{\pm}0.93\;mm$, p=0.000, $2.04{\pm}0.61$ vs $1.57{\pm}0.59$, p=0.012, $6.00{\pm}1.12$ vs $4.95{\pm}1.61\;cm$, p=0.003, respectively). Conclusion: Letrozole may augment folliculogenesis and improve the endometrial condition for implantation in normal cycling women. Ovulation efficacy of letrozole in anovulatory women was comparable to clomiphene citrate and letrozole may be more physiological in ovulation induction.

• Tuberculosis and Respiratory Diseases
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• v.40 no.6
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• pp.669-676
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• 1993

Background: DNA content analysis of human solid tumor is now widely performed by flow cytometric study. One of the most interesting and potentially important observation in this field is that proliferative activity(S-Phase fraction of cell cycle) may profoundly affect prognosis. Method: S-Phase fraction(SPF) have been measured by flow cytometric method using tumor cells isolated from paraffin embedded tissue. To evaluate the prognostic significance, SPF of squamous lung cancer cell was assessed in 21 patients who died without any specific treatment. Results: 1) Mean survival time of squamous lung cancer patients was 225(${\pm}162$) days. Survival time were shortened, when TNM stage and PS scale were advanced. 2) Mean value of SPF of squamous lung cancer patients was 23.4(${\pm}11.3$)%. SPF had nothing to do with advance of TNM stage and PS scale. 3) Mean survival time of high SPF group(more than 20% of cell proliferation cycle) and low SPF group were 153(${\pm}99$) days and 342(${\pm}180$) days(p<0.01). In each identical TNM stage and PS scale, there were also statistic significant differences in mean survival time between high and low SPF group. Conclusion: On multivariate analysis including TNM stage and performance status, SPF was the significant and independent prognostic factor in the primary squamous lung cancer patients group.

• Tuberculosis and Respiratory Diseases
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• v.45 no.5
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• pp.935-941
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• 1998

Background: As living and dead Mycobacteria could be amplified by polymerase chain reaction(PCR), it was considered that PCR was inappropriate for the monitoring of pulmonary tuberculosis after treatment. But we found negative conversion of PCR after successful treatment. We would like to know about the negative conversion rate of PCR and its conversion time after antituberculous treatment. Methods: We collected 113 sputums from the 16 patients of pulmonary tuberculsosis visiting Catholic University Hospital of Taegu Hyosung. We consecutively tested AFB smear, AFB culture and PCR by 2 to 4 weeks after antituberculous therapy. The patients were classified according to the chest X ray findings. Results: We detected negative conversion of PCR from all 16 patients of the pulmonary tuberculosis within 30 weeks after treatment. The average negative conversion time was $16{\pm}8$ weeks. The conversion time according to the chest X -ray findings were as follows : For the 8 cases of minimum were $9{\pm}5$ weeks, 4 cases of modreate advanced were $20{\pm}8$ weeks, and 4 cases of far advanced were $23{\pm}2$ weeks. The product of PCR was gradually decreased according to the duration of treatment. Conclusions: From the results of our study, we could utilize M. tubercuosis PCR for the prediction of therapy response and monitoring of the patient with pulmonary tuberculosis after treatment.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.831-837
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• 1995

Background: We conducted a study to determine the factors associated with, patterns of, and proportion of cases of pulmonary tuberculosis with multiple drug-resistance at Kosin medical center in Pusan. Methods: We abstracted data from 141 patients, who had active pulmonary tuberculosis and report forms of drug susceptibility between 1986 and 1994, and related the previous treatment history, the extent of lung involvement and the presence of cavities on chest X-ray films to the drug resistance. Results: Overall, 59(41.8%) of the 141 cases of tuberculosis were resistant to at least one drug and 29(20.9%) of the 139 cases were resistant to isoniazid(INH) and rifampin(RIF). Among the 63 patients with previous tuberculosis therapy, 40(63.5%) had isolates that were drug-resistant and 24(38.1%) were multi-drug resistant. Among the 78 without previous therapy, 19(24.4%) had isolates that were drug-resistant and 5(7.5%) were multi-drug resistant. For all 141, resistance to INH was most common(39.0%) followed by RIF(21.6%), ethambutol(EMB, 16.3%), $\rho$- aminosalicylic acid(10.8%), streptomycin(SM, 8.7%), and pyrazinamide(PZA, 8.0%). INH, RIF and PZA resistances were independently associated with a history of previous tuberculosis therapy (odds ratio; 3.3, 7.2 and 10.8 respectively), and RIF and SM resistance were significantly high according to the extent of lung involvement on the chest films(odds ratio; 2.9 and 2.8 respectively). Conclusions: We conclude, (1) that all persons in whom pulmonary tuberculosis is diagnosed should initially receive at least four-drug therapy(INH, RIF, PZA, and EMB or SM), (2) that susceptibility testing be done in all culture-positive patient, and (3) that those with a history of previous tuberculosis therapy or those who have advanced pulmonary tuberculosis need very careful clinical and microbiological follow-up.

• Tuberculosis and Respiratory Diseases
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• v.45 no.2
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• pp.280-289
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• 1998

Background: It is sometimes difficult to differentiate tuberculous pleural effusion from malignant pleural effusion by clinical symptoms, signs, by routine tests of pleural fluid, and by pathologic studies. And recently, it was discovered that cytokines such as IL-2, IFN-$\gamma$, TNF-$\alpha$ are elevated in tuberculous pleural fluid, and there have been several attempts to diagnose tuberculous pleural effusion by using these immunological mediators. There are several studies regarding the diagnostic value of IFN-$\gamma$, and there are two studies in Korea. But the diagnostic values of IFN-$\gamma$ in these studies were slightly lower than those in other countries. To compare the diagnostic value of IFN-$\gamma$ with those of CEA and ADA, and to determine the sensitivity and specificity of IFN-$\gamma$ in Korean, we mesured IFN-$\gamma$, CEA level and ADA activity in pleural effusions. Methods: ADA activity, IFN-$\gamma$ level and CEA level as well as cell count, differential count, and biochemical assays such as protein content and lactate dehydrogenase were measured in 40 cases of tuberculous pleuritis and 42 cases of malignant pleural effusion. Results: Tuberculous pleural fluid showed higher levels of IFN-$\gamma$ and ADA ($832.6{\pm}357.2$ pg/ml and $82.5{\pm}25.9$ U/L, respectively) than those of malignant pleural effusion ($2.6{\pm}8.0$ pg/ml and $19.2{\pm}10.9$ U/L, respectively) (p<0.01). Malignant pleural effusions showed higher median value (102.2 ng/ml) than tubercalous pleural effusions (1.8 ng/ml) (p<0.01). The sensitivities of IFN-$\gamma$, ADA, CEA were 0.97, 0.87, 0.67 and the specificities of IFN-$\gamma$, ADA, CEA were 1.0, 0.97, 1.0, respectively. There was no significant correlation between ADA activity and IFN-$\gamma$ level. Conclusion: This study showed that IFN-$\gamma$ test would be a very useful clinical test for differential diagnosis of tuberculous pleuritis and malignant pleural effusion because it is very sensitive and specific, although it is an expensive test.

• The Journal of Korean Academy of Prosthodontics
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• v.47 no.2
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• pp.206-214
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• 2009

Statement of problem: There are common clinical cases in which the mandibular first and second molars are missing unilaterally. Purpose: This study was designed to compare and evaluate the magnitude and distribution of stress produced by four kinds of mandibular unilateral free-end removable partial dentures that could be applied clinically in Kennedy class II cases. Material and methods: Four unilateral free-end removable partial dentures using clasp, Konus crown, resilient attachment, and flexible resin were fabricated on the photoelastic models of the Kennedy class II cases. The vertical load of 6㎏ was applied on the central fossa of the first molar of every removable partial denture in the stress freezing furnace and the photoelastic models were frozen according to the stress freezing cycle. After these models were sliced mesio-distally to a thickness of 6mm, the photoelastic isochromatic white and black lines of the sliced specimens were examined with the transparent photoelastic experiment device and photographs were taken with a digital camera. The fringe order numbers at eight measuring points in the photograph were measured with the naked eye. Results: The maximum fringe order number of each sliced specimen and the fringe order number at the residual ridge just below the loading point were in the decreasing order of the unilateral removable partial dentures using flexible resin followed by clasp, resilient attachment, and Konus crown. The fringe order number at the root apex of the second premolar was in the decreasing order of the unilateral removable partial dentures using clasp followed by flexible resin, Konus crown, and resilient attachment. Conclusion: The removable partial denture using Konus crown showed the most equalized stress distribution to the supporting alveolar bone of abutment teeth and residual ridge under the vertical loads. The removable partial denture using flexible resin can be applied to the case that has a better state of residual ridge than abutment teeth.

• The Journal of Korean Academy of Prosthodontics
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• v.58 no.3
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• pp.177-184
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• 2020

Purpose: The purpose of this study was to compare and evaluate the tensile bond strength of chairside reline resin to denture base resin fabricated by different methods (subtractive manufacturing, additive manufacturing, and conventional heat-curing). Materials and methods: Denture base specimens were fabricated as cuboid specimens with a width of 25 mm × length 25 mm × height 3 mm by subtractive manufacturing (VITA VIONIC BASE), additive manufacturing (NextDent Base) and conventional heat-curing (Lucitone 199). After storing the specimens in distilled water at 37℃ for 30 days and drying them, they were relined with polyethyl methacrylate (PEMA) chairside reline resin (REBASE II Normal). The subtractive and additive manufacturing groups were set as the experimental group, and the heat-curing group was set as the control group. Ten specimens were prepared for each group. After storing all bound specimens in distilled water at 37℃ for 24 hours, the tensile bond strength between denture bases and chairside reline resin was measured by a universal testing machine at a crosshead speed of 10 mm/min. The fracture pattern of each specimen was analyzed and classified into adhesive failure, cohesive failure, and mixed failure. Tensile bond strength, according to the fabrication method, was analyzed by 1-way ANOVA and Bonferroni's method (α=.05). Results: Mean tensile bond strength of the heat-curing group (2.45 ± 0.39 MPa) and subtractive manufacturing group (2.33 ± 0.39 MPa) had no significant difference (P>.999). The additive manufacturing group showed significantly lower tensile bond strength (1.23 ± 0.36 MPa) compared to the other groups (P<.001). Most specimens of heat-curing and subtractive manufacturing groups had mixed failure, but mixed failure and adhesive failure showed the same frequency in additive manufacturing group. Conclusion: The mean tensile bond strength of the subtractive manufacturing group was not significantly different from the heat-curing group. The additive manufacturing group showed significantly lower mean tensile bond strength than the other two groups.