Embryonic stem (ES) cells have potential for use in evaluation of developmental toxicity because they are generated in large numbers and differentiate into three germ layers following formation of embryoid bodies (EBs). In earlier study, embryonic stem cell test (EST) was established for assessment of the embryotoxic potential of compounds. Using EBs indicating the onset of differentiation of mouse ES cells, many toxicologists have refined the developmental toxicity of a variety of compounds. However, due to some limitation of the EST method resulting from species-specific differences between humans and mouse, it is an incomplete approach. In this regard, we examined the effects of several developmental toxic chemicals on formation of EBs using human ES cells. Although human ES cells are fastidious in culture and differentiation, we concluded that the relevancy of our experimental method is more accurate than that of EST using mouse ES cells. These types of studies could extend our understanding of how human ES cells could be used for monitoring developmental toxicity and its relevance in relation to its differentiation progress. In addition, this concept will be used as a model system for screening for developmental toxicity of various chemicals. This article might update new information about the usage of embryonic stem cells in the context of their possible ability in the toxicological fields.
Animals ; Embryoid Bodies ; Embryonic Stem Cells* ; Germ Layers ; Humans* ; Mass Screening ; Mice

PURPOSE: Recurrent abdominal pain syndrome (RAPS) is not uncommon in school-aged children, but the etiology and pathogenesis are not understood well. But recent studies suggest that motility disorder makes up a majority of the pathogenesis. The aim of this study was to investigate gastric emptying time (GET) which is a method to evaluate gastrointestinal motility in patients with recurrent abdominal pain syndrome. METHODS: Radionuclide GET was investigated in 34 patients who visited the Department of Pediatrics, Pusan National University Hospital due to recurrent abdominal pain from January 1996 to June 1997. After 8 hours of fasting, the patient received two pieces of toast and a fried egg tagged with 2 mci of 99mTc albumin colloid and sequential counting was accomplished. We calculated the geometric mean of two counts measured from AP-PA scans and investigated 60 minutes of intragastric radionuclide retention rate. RESULTS: A total of 34 patients (12 boys, 22 girls, M : F=1 : 1.8) participated in this study. The age ranged from 5 to 12 years and the mean age was 8.8 years. Associated symptoms were headache (7 patients), nausea (7 patients), constipation (2 patients), vomiting (1 patient), and diarrhea (1 patient). Anti-Helicobacter pylori IgG Ab was positive in 4 cases. Endoscopic gastritis was found in 6 cases. The mean of 60 minutes of intragastric radionuclide retention rate was 72 +/- 17% and 27 cases (79%) were delayed significantly. CONCLUSION: The results of our study suggest that delayed gastric emptying time is a cause of abdominal pain in patients with recurrent abdominal pain syndrome.
Abdominal Pain* ; Busan ; Child ; Colloids ; Constipation ; Diarrhea ; Fasting ; Female ; Gastric Emptying* ; Gastritis ; Gastrointestinal Motility ; Headache ; Humans ; Immunoglobulin G ; Nausea ; Ovum ; Pediatrics ; Vomiting

PURPOSE: Aspirin(acetylsalicylic acid) has been used to treat unstable angina and acute myocardial infarction in adults and Kawasaki disease in children. The antithrombotic effect of aspirin was attributed to its ability to inhibit platelet aggregation by inhibiting platelet cyclooxygenase, which leads to decreased thromboxane synthesis. The purpose of this study was to evaluate the effect on the platelet aggregation by low dose aspirin in Kawasaki patients and to learn the side effects of low-dose aspirin. METHODS: Fifty patients with Kawasaki disease who were treated with low-dose aspirin, and 22 normal children were studied from Jan. 1996 to Dec. 1997. The platelet count, bleeding time, clotting time, platelet aggregation test(induced by ADP, epinephrine, collagen and ristocetin) and blood aspirin level by colorimetric method were checked. RESULTS: The platelet count, bleeding time, and clotting time in the patient group were not significantly different from the control group. The mean maximum platelet aggregation was 54.4+/-12.8% induced by ADP, 15.9+/-11.7% by epinephrine, 55.5+/-23.8% by collagen, 52.6+/-32.2% by ristocetin in the patient group. It was significantly lower than the control group(P<0.05). The mean blood aspirin level in the patient group was 5.4+/-3.7mg/dl. Side effects of low-dose aspirin were bruise, epistaxis and hematuria. CONCLUSION: Low-dose aspirin therapy in patients with Kawasaki disease inhibited platelet aggregation, but attention would be needed because of the tendency to bleed in these patients. Further investigations should be focused on the subject such as the onset of the maximal antiplatelet effect and time needed for the recovery of platelet function.
Adenosine Diphosphate ; Adult ; Angina, Unstable ; Aspirin* ; Bleeding Time ; Blood Platelets* ; Child ; Collagen ; Contusions ; Epinephrine ; Epistaxis ; Hematuria ; Humans ; Mucocutaneous Lymph Node Syndrome* ; Myocardial Infarction ; Platelet Aggregation* ; Platelet Count ; Prostaglandin-Endoperoxide Synthases ; Ristocetin

No abstract available.
Carcinoma, Transitional Cell* ; Tuberculosis, Renal* ; Ureter*

PURPOSE: After extraction, the alveolar bone tends to undergo atrophy in three-dimensions. The amount of alveolar bone loss in the horizontal dimension has been reported to be greater than the amount of bone loss in the vertical dimension, and is most pronounced in the buccal aspect. The aim of this study was to monitor the predictive alveolar bone level following the extraction of anterior teeth seriously involved with advanced chronic periodontitis. METHODS: This study included 25 patients with advanced chronic periodontitis, whose maxillary anterior teeth had been extracted due to extensive attachment loss more than one year before the study. Periapical radiographs were analyzed to assess the vertical level of alveolar bone surrounding the edentulous area. An imaginary line connecting the mesial and the distal ends of the alveolar crest facing the adjacent tooth was arbitrarily created. Several representative coordinates were established in the horizontal direction, and the vertical distance from the imaginary line to the alveolar crest was measured at each coordinate for each patient using image analysis software. Regression functions predicting the vertical level of the alveolar bone in the maxillary anterior edentulous area were identified for each patient. RESULTS: The regression functions demonstrated a tendency to converge to parabolic shapes. The predicted maximum distance between the imaginary line and the alveolar bone calculated using the regression function was 1.43+/-0.65 mm. No significant differences were found between the expected and actual maximum distances. Likewise, the predicted and actual maximum horizontal distances did not show any significant differences. The distance from the alveolar bone crest to the imaginary lines was not influenced by the mesio-distal spans of the edentulous area. CONCLUSIONS: After extraction, the vertical level of the alveolar ridge increased to become closer to the reference line connecting the mesial and distal alveolar crests.
Alveolar Bone Loss ; Alveolar Process ; Atrophy ; Chronic Periodontitis ; Humans ; Periodontitis* ; Tooth Extraction ; Tooth* ; Vertical Dimension

Lynch syndrome is also called Hereditary nonpolyposis colorectal cancer (HNPCC). It is characterized by a risk of colorectal cancer and other cancers of the endometrium, ovary, stomach, small intestine etc. The increased risk is due to inherited mutations that impaired DNA mismatch repair. Two to three percentage of colon cancer is caused by Lynch syndrome. A family history of colon cancer occurs at a young age. We experienced one case of Lynch syndrome who had had stomach cancer, endometrial cancer and colon cancer recently. Hence we report this case with a brief review of literature.
Colonic Neoplasms ; Colorectal Neoplasms ; Colorectal Neoplasms, Hereditary Nonpolyposis ; DNA Mismatch Repair ; Endometrial Neoplasms ; Endometrium ; Female ; Humans ; Intestine, Small ; Ovary ; Stomach ; Stomach Neoplasms

Present study was performed to describe the morphological and molecular characterization of Toxocara tanuki (Nematoda: Ascaridae) from Korean raccoon dog, Nyctereutes procyonoides koreensis, naturally infected in the Republic of Korea (Korea). Juvenile and adult worms of T. tanuki were recovered in 5 out of 10 raccoon dogs examined and the larval worms were detected in 15 out of 20 muscle samples (75%). Small lateral alae were observed on the cranial end of the body in male and female adults and 2 long spicules (3.0–3.5 mm) were characteristically observed in the posterior end of males. In SEM observation, 18 pairs of proximal precloacal, a precloacal median, a postcloacal median and 5 pairs of postcloacal papillae were uniquely revealed in the posterior portion of males, but the proximal papillae were not shown in the lateral ends of females. Molecular analysis on the 18S rRNA partial DNA sequences was revealed the same finding in both samples, adult worms and muscle larvae, which are closely related to T. tanuki. In conclusion, it was confirmed for the first time that T. tanuki is indigenously distributed, the Korean raccoon dog is acted as the natural definitive host of this nematode in Korea and the morphological characteristics of T. tanuki were shown in specific structure for single postcloacal median papilla in male.
Adult ; Base Sequence ; Female ; Humans ; Korea ; Larva ; Larva Migrans ; Male ; Raccoon Dogs ; Raccoons ; Republic of Korea ; Toxocara

Total 513 heterophyid flukes were collected from a carcass of wild Korean raccoon dog, Nyctereutes procyonoides koreensis, in Korea. With morphological and molecular characteristics, the flukes were identified to Cryptocotyle lata. The adult C. lata were minute, transparent, pentagonal, 522 µm long by 425 µm wide. Ceca extended into post-testicular region. Ventrogenital sac elliptical, 79 µm by 87 µm with genital pore and ventral sucker. Two testes semielliptical and slightly lobed, located in the posterior region, right testis 173 µm by 155 µm, left testis 130 µm by 134 µm. In a phylogenetic tree, the fluke specimen of this study was grouped with C. lata divergent from Cryptocotyle lingua. We report here N. procyonoides koreensis first as a natural definitive host of C. lata.

We report a species of diplostomid fluke recovered from 3 carcasses of wild Korean raccoon dog, Nyctereutes procyonoides koreensis, in Korea. A total of 107 diplostomid flukes were recovered from the small intestines of Korean raccoon dogs, which were obtained from the Gangwon Wildlife Medical Rescue Center. Worms fixed with 10% neutral formalin were subjected to microscopic observation and those fixed in 70% ethanol were used for molecular genomic analysis. The worm was divided into 2 separate parts, forebody and hindbody, with a total length of 3,020-4,090 (3,855) µm and a width of 1,210-1,770 (1,562) µm. The boat-shaped forebody has a pair of characteristic tentacular appendage, 2 suckers, holdfast organ, and vitelline follicles. The oval to cylindrical hindbody has reproductive organs. The ovary was round or elliptical and located in the anterior of the testes. Two large testes were slightly segmented and tandemly arranged, occupying almost half of hindbody. The short uterus contained a relatively small number of unembryonated eggs sized 130-140×85-96 µm. The partial sequence of 18S rRNA of this fluke was consistent with Alaria alata. Based on the morphological and molecular characteristics, the diplostomid flukes recovered from the small intestine of Korean raccoon dogs were identified as A. alata (Digenea: Diplostomidae).

OBJECTIVE: To investigate the influence of transforming growth factor-alpha (TGF-alpha) on preimplantation development, implantation and epidermal growth factor receptor (EGFR) expression in mouse embryos. MATERIALS AND METHODS: Eight-cell stage mouse embryos were cultured for 48 hours with TGF-alpha at concentrations of 1.0, 10 and 100 ng/ml. Embryos not treated with TGF-alpha served as control. The percentages of embryos which developed to blastocyst stage, expanded, hatched blastocyst stage and in vitro implantation at 48 hours were determined. Riverse transcription-polymerase chain reaction (RT-PCR) has been used to examine the expression of EGFR in developed hatched blastocysts. Following reverse transcription, strategically designed nested primers, optimized for specificity, were used for amplification from the cDNA equivalent of a single embryo. The products were then verified by restriction enzyme digestion and sequence analysis. RESULTS: The percentages of embryos which developed to blastocyst stage were significantly higher following incubation with TGF-alpha at concentration of 10 ng/ml(p<0.05). The percentages of embryos which developed to expanded blastocyst stage were significantly higher in TGF-alpha treatment group at concentration of 100 ng/ml(p<0.05). The percentages of embryos which developed to hatched blastocyst stage were significantly higher following incubation with TGF-alpha at concentration of 10 ng/ml and 100 ng/ml(p<0.05). The percentages of implanted blastocyst in vitro were significantly higher following incubation with TGF-alpha at concentrations of 100 ng/ml compared to the control(p<0.05). The mRNA concentration of EGFR in embryos treated with 100 ng/ml of EGF was significantly higher than those of the control and other EGF treatment groups(p<0.005, p<0.05, p <0.05, respectively). CONCLUSION: TGF-alpha may stimulatory role in embryonic development, implantation and expression of EGFR in embryo itself. These results suggest that TGF-alpha may act directly on the mouse embryo and favor its implantaion, irrespective of the presence or absence of the endometrium.
Animals ; Blastocyst ; Digestion ; DNA, Complementary ; Embryonic Development ; Embryonic Structures* ; Endometrium ; Epidermal Growth Factor* ; Female ; Mice* ; Pregnancy ; Receptor, Epidermal Growth Factor* ; Reverse Transcription ; Rivers ; RNA, Messenger ; Sensitivity and Specificity ; Sequence Analysis ; Transforming Growth Factor alpha