• Korean Journal of Veterinary Research
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• v.1 no.1
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• pp.53-53
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• 1961

During the period from 1956 to 1959, a serological survey was conducted in au effort to assessing the incidence of brucellosis in various domestic animals in Korea. The following results were obtained. 1. Seventy-six dairy cattle which were imported in the year of 1956 had 9 positive reactors (11.84%). Of 1127 goats imported in 1956 and 1958, eleven(0.98%) were reactor animals. 2. In 1956, of 108 dairy cattle tested 10(9.25%) were reactors. In 1937 and 1958, a total of 155 dairy cattle examined hid ten (6.45%) positive reactors. In 1959, of 127 dairy cattle examined two were reactor animals. 3. In 1958 and 1959, 432 goats in some districts in Korea were subject to test for brucellosis and the test revealed five (1.15%) reactors. In 1958, 683 swine serum samples were examined and eleven (1.04%) were positive. In 1959, 1133 Korean cattle were tested and seven samples (0.64%) showed positive reactions. 4. In the month of July in 1939, 580 beef cattle in Cheju National Ranch and Branch were examined and 111 (19.13%) were found to be reactors. In October of the same year, 157 cattle, consisting of reactor and suspicious cattle groups, were tested, of which 71 samples reacted positive and 47 remained suspicious. 5. In December of the year of 1958, there occurred. an outbreak of brucellosis in a swine herd in the Sachon Branch Experimental Station. Seven serological tests on 438 swine serum samples were conducted, of which 122 (27.87%) were found positive. 6. Dairy cattle No. 33 and No. 35 which had been imported in 1956 and detected as highly positive, were examined for a prolonged period to follow the variation of antibody titers. A marked drop in antibody titer was seen two months after the initial test while the re-increase in titer was observer our months after the first examination.

• Korean Journal of Veterinary Research
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• v.40 no.2
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• pp.361-371
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• 2000

It has been recently reported that 2-bromopropane (2-BP) induces male reproductive toxicity in both human and experimental animals. However, delayed effects of 2-BP on male reproductive system have not been investigated in detail. The present study was conducted to investigate the testicular toxicity of 2-BP and to determine the recovery of normal spermatogenesis in Sprague-Dawley rats. Male rats aged 5 weeks were administered 1,000mg/kg 2-BP by gavage daily for 4 weeks and sacrificed sequentially at 1, 2, 3, 4 and 12 weeks after initiation of 2-BP treatment. Testicular toxicity was evaluated qualitatively by histopathological examinations and quantitatively by reproductive organ weights, spermatid head count, and repopulation index. In the 2-BP treated rats, the body weights was significantly suppressed and the weights of testes and epididymides were also decreased in a time-dependent manner. On histopathological examination, spermatogonia in stages I-VI and preleptotene and leptotene spermatocytes in stages VII-IX were strongly depleted at 1 week of dosing. Spermatogonia were depleted extensively in all spermatogenic stages at 2 weeks. Continuing with the evolution of spermatogenic cycle, zygotene spermatocytes, pachytene spermatocytes, and round spermatids were sequentially depleted at 2, 3, and 4 weeks of dosing due to the depletion of their precursor cells. Vacuolization of Sertoli cells and spermatid retention were also observed at all time points, suggesting that 2-BP induced Sertoli cell dysfunction. At 12 weeks, after 8 weeks recovery, most of the tubules appeared severely atrophic and were lined by Sertoli cells only. Leydig cell hyperplasia in the interstitial tissue was also found. In addition, dramatic reductions in the number of spermatid heads and repopulation index were observed, indicating that 2-BP-induced testicular injury is irreversible. These results indicate that 4 weeks repeated-dose of 1,000mg/kg 2-BP results in a progressive germ cell loss due to the depletion of spermatogonia followed by long-term testicular atrophy in SD rats.

• Restorative Dentistry and Endodontics
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• v.31 no.5
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• pp.398-408
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• 2006

The purpose of this study was to verify the usefulness of MTT analysis as a tool of measurement of the periodontal ligament cell viability from the extracted rat molar. A total of 80 Sprague-Dawley white female rat of 4 week-old with a body weight of 100 grams were used. The maxillary left and right, first and second molars were extracted under Ketamine anesthesia. Twenty-four teeth of each group (divided as five groups depending upon the time-lapse after extraction such as Immediate, 10, 20, 40 and 60 minutes) were immersed in $200{\mu}l$ of MTT solution (0.5 mg/ml) and processed for optical density measurements. Another 10 teeth of each group were treated as same as above and sectioned at $10{\mu}m$ for microscopic examination. All measurements values were divided by the value of hematoxylin-eosin staining which represented the volume of each corresponding samples. Immediate and 10 minute groups showed highest MTT values followed by 20, 40, and 60 minutes consecutively. Statistical significance (p<0.05) existed between all groups except in immediate versus 10 minute groups and 40 versus 60 minutes. Histological findings also showed similar findings with MTT results in crystal shape and crystal numbers between the experimental groups. These data indicate that in vivo MTT analysis nay be of value for evaluation of the periodontal ligament cell viability without time- consuming cell culturing processes.

• Clinical and Experimental Reproductive Medicine
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• v.26 no.2
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• pp.171-178
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• 1999

The follicular fluid (FF) of ovary contains various biological active products which affected on the growth of follicles and the fertilization of oocyte in physiological reproductive process of mammals. This study was designed to determine the effects of human FF on fertilization of oocyte and embryonal development in vitro culture. The FF was prepared as clear without blood contamination by needle aspiration from mature follicles of human at the time of oocytes retrieval for in vitro fertilization (IVF). As the medium for culture in vitro of embryonal cells, human tubal fluid (HTF) supplemented with follicular fluids at concentrations of 10%, 40% and pure FF were used. These effects were compared to control group of cultured embryos in HTF supplemented with 0.4% BSA (bovine serum albumin). For IVF, 64 eggs in control group, 67 eggs in 10% FF, 57 eggs in 40% FF and 64 eggs in pure FF were respectively allocated. And the rates of fertilization were almost similar in all groups as resulting 82.81% in control, 85.07% in 10% FF, 87.71% in 40% FF and 81.25% in pure FF. On the examination for embryonal cleavage from fertilized eggs, the rates of developing to 4 cell stage was similar in all groups, as results 98.11% in control, 98.27% in 10% FF and 98% in 40% FF but 78.84% in pure FF. And the rates of developing to 8-16 cell stage were significantly reduced as 44% in 40% FF and 44.23% in pure FF (p<0.05) compare to 71.69% in control media. As likewise, the rates of developing to morular stage were also significantly reduced to 36% (p<0.05) and 21.15% (p<0.01) respectively in 40% FF and pure FF. And the rates to blastocystic stage of embryo was lowest as 7.69% in pure FF (Table 1). The quality of embryonal cells on cleavage to the 8-16 cell stage was poorer, higher concentrations of FF. The rates of grade 1 in pure FF, as 23.07%, was lowest compare to those of other groups, in which the rates of grade 1 in control, 10% FF and 40% FF were 58.49%, 47.36% and 34% respectively. And on the contrary, the rate of grade 4 in pure FF was highest as 23.07%, while those were 5.66% in control, 8.77% in 10% FF and 20% in 40% FF (Table 2). On the viability of embryos, the rate of embryonal cell death was more rise, at the higher concentrations as well as longer exposure in the follicular fluid. At 48 hours after in vitro culture of embryos, the rate of survival embryos in pure FF was markedly lowered as 44.23%, compare to that of control (p<0.05). But there was not significant difference between the rates of survival embryos in each group beside the pure FF, which the rates were 77.35% in control, 70.17% in 10% FF and 60% in 40% FF respectively. And at 72 hours after in vitro culture, the rates of survival embryos were also significantly dropped to 21.15% in pure and 36% in 40% at concentration of FF compare to 62.26% in control (p<0.05, p<0.01). Finally, the rate of embryonal death at 96 hours after in vitro culture was highest as 82.69% in pure FF among all groups which those were 35.84 in control, 56.14% in 10% FF and 64% in 40% FF respectively (Fig. 1, 2, 3). In conclusion, this study suggests that the FF has no effects, in particular, to the in vitro fertilization of oocytes but exerted a bad effect to the cleavage, quality and viability of the embryonal cells during in vitro culture. However, the FF is harmful on embryonal development at conditions in higher concentration and especially on the embryos after $8{\sim}16$ cell stage.

• The korean journal of orthodontics
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• v.26 no.2 s.55
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• pp.153-162
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• 1996

Rapid maxillary expansion is widely used for the correction of anteroposterior discrepancies, constriction of the maxillary arch, etc. This experiment was undertaken to examine the serial changes in the osteogenesis as well as the collagen fiber bundles in the intermaxillary suture during the rapid maxillary expansion treatment. Four young female dogs aged 6 to 8 months old and not showing menarche yet were used for the experiment. The maxillary impression of dogs were taken, expansion device cast and Hyrax screw soldered at the midline in the 1st premolar area. RME device was delivered to the dogs and the activation of 0.25 mm per quarter-turn was done 2 times per day for 10 days until 5 mm separation was made. Separation of the maxilla was confirmed by X-ray. The animals were sacrificed on 0, 15, 30, 60 days from the finish of maxillary separation and preparations for light microscopy and surface electron microscopy were made. The sutures were cut into frontal serial sections for examination of the histological reactions. The following results were obtained and the conclusions made. 1. The edges of the two palatal plates bordering the midpalatal suture which at the beginning of the retention period were mainly composed of compact bone, underwent extensive resorption followed by new bone formation and gradually became spongy bone rich in bone marrow which in the 60 day retention animal became the compact bone with short intermaxillary suture space. During this transformation, newly formed trabecular bone tissues were added to the original margin. 2. Throughout the expansion period, the collagen fibers underwent successive changes such as stretching, loss of polarity, and finally fibrillogenesis. Towards the end of the expansion procedure, sharpey's fiber formation in newly formed bones were observed. 3. Bony spicules were found in the initial stage of retention on occlusal topographic X-rays, which later were confirmed to have ossified. 4. Judging from the histological changes occuring during the experimental expansion, excessive expansion will cause an excessive bleeding, and retard the remodeling of intermaxillary suture. According to the above results, the bone remodeling after rapid maxillary expansion was preceded by the migration of migratory cells into the intermaxillary suture area. The bone remodeling phenomena were on-going during the 2 months retention sample.

• Journal of dental hygiene science
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• v.11 no.6
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• pp.521-526
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• 2011

The purpose of this study was to evaluate the long term effect of school-based oral health program on decrease of dental caries among elementary school children. The subjects of this study were total 727 students of one elementary school in Deagu, Korea. They had received school-based oral health programs for more than one year since 2004. This school-based oral health program included regular oral examination, fluoride mouth-rinsing, pit-and-fissure sealing, APF gel application, tooth brushing instruction and take the xylitol tablet after lunch during school days. The subjects' oral health status were examined by two calibrated dentists every year from 2004 to 2009. The DMFS index of $1^{st}$ grade to $6^{th}$ grade experimental and control group was 0.07, 0.39, 0.55, 0.67, 0.81, 1.79 and 0.31, 0.86, 1.07, 1.04, 2.71, 3.08 respectively. It's significantly different in $5^{th}$ grade(p<0.001) and $6^{th}$ grade(p=0.018) when it compare with control group. This study partially showed effect of school-based oral health programs on decrements of dental caries. This program should be expanded widely among elementary school in Korea. Xylitol tablet also recommended to included in school-based oral health programs.

• Proceedings of the KOR-BRONCHOESO Conference
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• 1977.06a
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• pp.4.4-5
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• 1977

The vibratory energy introduced into the external ear canal is changed by the mechanical factors of eardrum itself, the motility of ossicles, and the air cushion of tympanic cavity and the like. This study was designed to investigate the volume of middle ear cavity and mastoid air cell system as a factor of determining the accoustic impedance of middle ear system. The author studied how the increase in air volume of middle ear cavity effects on the acoustic impedance of middle ear system with dogs' ears and researched the correlation between the degree of pneumatization of temporal bones and the acoustic impedance of middle ear system by comparing the radiological findings of pneumatization (Law's and Towne's projection) with the acoustic impedance measurements with Madsen ZO 70. The result is as follows: 1 The tympanometric findings in control state revealed the curves of type A, and did not change in its configuration by the increase in the air volume of dogs middle ear system. 2. The static compliance of middle ear revealed a distinct and linear increase in proportion to the increase in air volume of middle ear system; the rate of increase was $0.05{\pm}0.02$ cc of static compliance per cc of air volume. 3. Authenticated in the above result and the tendency to increase in static compliance in proportion to the increase in the degree of pneumatization of temporal bones, there was significant regression equation between the degree of pneumatization of temporal bones (x variable) and the static compliance of middle ear system; $y=0.19x{\pm}0.16{\pm}0.05$ It is suggested that the difference in volume of middle ear system plays an important role in the change of the static compliance of middle ear, and the author concludes that the measurement of static compliance of middle ear has clinical value as diagnostic means of evaluating the degree of pneumatization of temporal bones along with some radiological examination.

• Clinical and Experimental Reproductive Medicine
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• v.11 no.1
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• pp.17-32
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• 1984

There are numerous reports on the relative risk of pelvic inflammatory disease among the users versus the nonusers of intrauterine device. Reported relative risk varied from no difference between the two groups to 3-9 fold increase in the users. In an attempt to define this relative risk of pelvic inflammatory disease and related microorganisms ,pelvic organ observation and bacteriological study were done through laparoscopy. Specimens for microbiologic culture were obtained simultaneously from the fallopian tubes via laparoscopy and from the endocervix via regular pelvic examination method. The study population was consisted of 30 I.U.D.users and 35 J.U.D.nonusers who visited the Yonsei University Severance Hospital and the Sung-Ga Hospital for laparoscopic sterilization. The results obtained were as follows: 1. There was no difference in age distribution, economic status and numbers of parity and abortion between I.U.D. users and I.U.D. nonusers. 2. The pelvic inflammatory findings were noted on laparoscopy in 2 cases of I.U.D. users, with an incidence of 6.6%. And no pelvic inflammatory finding was noted in any of the nonusers,but this difference was not statistically significant (p>0.005). 3. All the bacteriologic culture of the specimens from the fallopian tubes of both groups yielded negative results. 4. The bacteriologic culture of the spec imens f rom the endocervix revealed more frequent isolation of possible pathogen such as Hem ophilus ,alpha-Streptococcus ,Corynebacteria, Bacteroides in the I.U.D.users than in the nonusers.But,this difference was also not statistically significant (p>0.005).

• Restorative Dentistry and Endodontics
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• v.34 no.5
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• pp.406-414
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• 2009

The purpose of this study was to examine the effect of hydrogen peroxide at different application time and concentrations on the microtensile bond strength of resin restorations to the deep and the pulp chamber dentin. A conventional endodontic access cavity was prepared in each tooth, and then the teeth were randomly divided into 1 control group and 4 experimental groups as follows: Group 1, non treated; Group 2, with 20% Hydrogen peroxide ($H_2O_2$); Group 3, with 10% $H_2O_2$; Group 4, with 5% $H_2O_2$; Group 5, with 2.5% $H_2O_2$; the teeth of all groups except group 1 were treated for 20, 10, and 5min. The treated teeth were filled using a Superbond C&B (Sun medical Co., Shiga, Japan). Thereafter, the specimens were stored in distilled water at $37^{\circ}C$ for 24-hours and then sectioned into the deep and the chamber dentin. The microtensile bond strength values of each group were analyzed by 3-way ANOVA and Tukey post hoc test(p < 0.05). In this study, the microtensile bond strength of the deep dentin (D1) was significantly greater than that of the pulp chamber dentin (D2) in the all groups tested. The average of microtensile bond strength was decreased as the concentration and the application time of $H_2O_2$ were increased. Analysis showed significant correlation effect not only between the depth of the dentin and the concentration of $H_2O_2$ but also between the concentration of H202 and the application time(p < 0.05), while no significant difference existed among these three variables(p > 0.05). The higher $H_2O_2$ concentration, the more opened dentinal tubules under a scanning electron microscope(SEM) examination.

• Korean Journal of Veterinary Research
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• v.44 no.4
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• pp.507-513
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• 2004

Aflatoxins are produced mainly by Aspergillus flavus and Aspergillus parasiticus that grow in improperly stored cereals. Aflatoxin B1 ($AFB_1$) is a potent hepatocarcinogen in a variety of experimental animals including human beings. In spite of a high attention to the hepatocarcinogenecity of $AFB_1$, the relative toxicity of aflatoxins ($AFB_2$ and $AFG_1$) is not fully clarified. Sprague-Dawley male rats were orally administered with $AFB_1$, $AFB_2$, and $AFG_1$ at the dose of 250 ${\mu}g/kg$ (additionally including a dose of $1250{\mu}g/kg $ for $AFB_1$) body weight. Animals were then killed at 12, 24 or 48 hrs following aflatoxin exposure. Subsequently the immunohistochemical examination of p53, cytochrome p450 1A1 (CYP450 1A1), and glutathione-S-transferase placental form (GST-P) were performed. The level of the 8-OxodG in the liver was determined. Expressions of CYP450 1A1 and p53 were high in the liver of rats through 48 hrs after treatment of $AFB_1$ at the single dose of $250{\mu}g/kg $. This pattern was more clear as increasing doses. The treatment of $AFB_2$ and $AFG_1$ did not affect the expression of CYP450 1A1 but it caused weak expression of p53. The activity of GST were not found in the liver of rats treated with aflatoxins. The formation of 8-OxodG by $AFB_1$ increased in a dose-dependent manner up to 24 hrs after a single treatment of $AFB_1$ thereafter decreased to the level of control. The treatment of $AFB_2$ and $AFG_1$ did not affect the levels of 8-OxodG in the liver of rats with increasing time. These results in the present study indicate that $AFB_1$ among aflatoxins with low comparable levels is the most toxic as determined by early biomarkers such as CYP450 1A1, p53, GST-P, and 8-OxodG.