Researches on manipulating pluripotent stem cells derived from blastocysts or primordial germ cells (PGCs) have a great advantage for developing innovative technologies in various fields of life science including medicine, pharmaceutics, and biotechnology. Since their first isolation in the mouse embryos(1), stem cells or stem cell-like colonies have been continuously established in the mouse of different strains(21), cattle(2, 3), pig(4, 5), rabbit(6, 7), and human(9). However, full-term development originated from established pluripotent cells, which is an absolute criterion for proving cell pluripotency and differentiation, has only been reported in the mouse(22). Due to technical difficulties, no further progress has been made in the establishment of animal embryonic stem (ES) cell line. Alternatively, the use of embryonic germ (EG) cells was selected to establish an animal stem cell line. EG cells also have pluripotent characteristics, which were proven by morphological assay, intracellular alkaline phosphatase activity, and reactions with cell surface-specific markers. The finding of Labosky et al.(23) on germline chimera development after transfer to embryos clearly proved the pluripotency of EG cells and their similar characteristics with ES cells. Avian transgenesis has an unlimited value in biotechnology industry, since its applicability as a bioreactor has proven to be greater than that of mammalian species(24). In the chicken, EG cells can be extensively utilized instead of ES cells for efficiently inducing transgenesis mediated by germline transmission. Recently, PGCs collected from the embryonic gonad were suggested to be useful in establishing avian stem cells. Technical feasibility and applicability of gonadal PGCs (gPGCs) to germline chimera production were also confirmed(25) and a gPGC culture system to establish EG cells was subsequently developed(15).
Alkaline Phosphatase ; Animals* ; Biological Science Disciplines ; Bioreactors ; Biotechnology ; Blastocyst ; Cell Line ; Chickens ; Chimera ; Embryonic Germ Cells ; Embryonic Stem Cells ; Embryonic Structures ; Gene Transfer Techniques ; Germ Cells ; Gonads ; Mice ; Pluripotent Stem Cells ; Stem Cell Research* ; Stem Cells*

Early postnatal period is considered as the critical period for formation and maturation of the synapses. And cerebellum has the major role in the development of equilibrium and somatic motor function, especially in the early postnatal age. So, I performed this study to investigate the morphological changes of the synapses in the rat cerebellar cortex. Sprague-Dawley rats were used as experimental animals. The ultrastructure of Synapses was observed in six groups ; 3-day, 1-week, 2-week, 3-week, 4-week, 5-week. The results are as followes. 1. After birth, the synaptic density was increased gradually by the forth week. 2. The length of postsynaptic densities was increased significantly in the period between first and second week. 3. There was significant correlation between the length of postsynaptic densities and the area of synaptic vesicle clusters. 4. The frequency of asymmetric and/or frown synapses was increased dramatically with advancing ages. According to the above results, the synaptogenesis in the rat cerebellum is very active in their early postnatal periods. And asymmetric and/or active frown synapses were the major type of synapses with advancing ages.
Animals ; Cerebellar Cortex* ; Cerebellum ; Critical Period (Psychology) ; Parturition ; Post-Synaptic Density ; Rats* ; Rats, Sprague-Dawley ; Synapses* ; Synaptic Vesicles

No abstract available.
Amino Acids* ; Animals ; gamma-Aminobutyric Acid* ; Horns* ; Neurons* ; Rats* ; Receptors, GABA*

Ependymomas constitute no more than 5 to 7% of all primary CNS neoplasm and their biologic behavior is difficult to predict by microscopic appearances. Recently, many studies have attempted to correlate biologic behavior with tumor proliferation index, tumor suppressor gene and oncogene using immunohistochemical stains. We evaluated 25 cases of surgically resected intracranial ependymomas for the proliferation activity using Ki-67, and expression of p53 and bcl-2 protein with regard to the prognosis. The cases were divided into 17 ependymomas (WHO Grade II), 3 papillary ependymomas (WHO Grade II), and 5 anaplastic ependymomas. Clinically, the patients were divided into two groups, recurrent (18 cases) or non-recurrent (7 cases). The Ki-67 proliferation index was significantly higher in the recurrent group (p<0.05) and in the younger ages (correlation index=0.534). Although Ki-67 proliferation index was higher in anaplastic ependymoma, it was not significant statistically (p>0.05). p53 protein expression tended to increase in the patients who had anaplastic ependymoma and in the recurrent group. bcl-2 expression was not correlated with histologic grade or recurrence of the tumor. We conclude that Ki-67 proliferation index and p53 expression are important markers for predicting biologic behavior of ependymoma.
Coloring Agents ; Ependymoma* ; Genes, Tumor Suppressor ; Humans ; Oncogenes ; Prognosis ; Recurrence

BACKGROUND: It has been well known that cFos protein, one of the immediate-early gene proteins, was a cellular marker to characterize physiological or anatomical property of neural networks in mammalian brain. The purpose of this study was to evaluate quantitative change of cFos protein expression in rat brain nuclei concerned with regulation of blood pressure according to severity of hypotension and compare the spatial pattern of cFos between hemorrhagic hypotension and non-hemorrhagic hypotension elicited by vasodilatation. METHODS: The mean blood pressure (MBP) in the femoral artery was recorded by using pressure transducer and polygraph. Nitroprusside was injected into the femoral vein with constant flow rate by means of osmotic pump in which the dosage was 5microgram Per kg a minute. Immunohistochemical staining was Performed by using conventional ABC method to visualize cFos-like immunoreactive (cFLI) neurons in many brain nuclei and FLI cells were counted by image analyser. RESULTS: Mild hemorrhage group with MBP of 70-80 mmHg showed significant increase of cFLI expression in the paraventricular nuclei and supraoptic nuclei. In contrast, severe hemorrhage group with MBP of 50 mmHg increased significantly cFLI expression in the rostral ventrolateral medulla, periventricular thalamic nucleus, central gray matter, medial vestibular nuclei as well as the nuclei seen in mild hemorrhage group. Nitroprusside induced hypotension exhibited a similar spatial pattern of ctrl expression to severe hemorrhage group. CONCLUSION: These results suggest that severe reduction of blood pressure induces expression of cFLI neurons in the neural network systems that control vital organs.
Animals ; Blood Pressure ; Brain* ; Femoral Artery ; Femoral Vein ; Genes, Immediate-Early ; Hemorrhage ; Hypotension* ; Neurons ; Nitroprusside ; Rats* ; Transducers, Pressure ; Vasodilation ; Vestibular Nuclei

No abstract available.
Cardiopulmonary Bypass* ; Child* ; Colloids* ; Humans ; Prospective Studies*

To evaluate the correlation between the internal echo patterns and henodynamics in hepatic cavernous hemangioma, we compared the interanal echo pattern with the hemodynamic pattern examined by intravenous bolus CT(multi-phase incremental bolus dynamic CT) in 34 diagnosed hemangiomas (25 patients). We classified cavernous hemangiomas as two different hemodynamic patterns according to the findings of the early phase of intravenous bolus CT scans. Early enhancing type means that most portion of a mass is enhanced during the early hpase and late enhancing type means that only minimal peripheral portion of a mass is enhanced during the early phase. We classified ultrasonogrphic patterns as hypoechoic and hyperechoic according to main echogenicity of the mass. The late enhancing type tends toward the high echo type (20/21) and the early enhancing type tends to ward the low echo type (11/13) (p<0.01) Therefore, we believe that the early enhancing type which represents rapid contrast inflow toward mass, contains large portions of cavernous space and showes hypoechoic, but late enhancing type which represents late contrast inflow toward a mass, contains large portions of fibrous space and showes hyperechoic. In conclusion, there was significant correlation between internal hemodynamics and echo patterns in hepatic cavernous hemangioma.
Hemangioma ; Hemangioma, Cavernous* ; Hemodynamics* ; Tomography, X-Ray Computed

To evaluate the correlation between the internal echo patterns and henodynamics in hepatic cavernous hemangioma, we compared the interanal echo pattern with the hemodynamic pattern examined by intravenous bolus CT(multi-phase incremental bolus dynamic CT) in 34 diagnosed hemangiomas (25 patients). We classified cavernous hemangiomas as two different hemodynamic patterns according to the findings of the early phase of intravenous bolus CT scans. Early enhancing type means that most portion of a mass is enhanced during the early hpase and late enhancing type means that only minimal peripheral portion of a mass is enhanced during the early phase. We classified ultrasonogrphic patterns as hypoechoic and hyperechoic according to main echogenicity of the mass. The late enhancing type tends toward the high echo type (20/21) and the early enhancing type tends to ward the low echo type (11/13) (p<0.01) Therefore, we believe that the early enhancing type which represents rapid contrast inflow toward mass, contains large portions of cavernous space and showes hypoechoic, but late enhancing type which represents late contrast inflow toward a mass, contains large portions of fibrous space and showes hyperechoic. In conclusion, there was significant correlation between internal hemodynamics and echo patterns in hepatic cavernous hemangioma.
Hemangioma ; Hemangioma, Cavernous* ; Hemodynamics* ; Tomography, X-Ray Computed

PURPOSE:Although Hashimoto's thyroiditis is the most common cause of goiter in children and adolescents, it is not clear what proportion of patients become hypothyroid and which tests are the best predictors of this state. To determine whether these kinds of variations occur in the course of Hashimoto's thyroiditis and whether the size of the thyroid gland or immunologic markers correlate with the course or outcome of Hashimoto's thyroiditis are main objects of our study. METHODS:A total number of 48 patients who were diagnosed as having Hashimoto's thyroiditis at the Department of Pediatrics, Asan Medical Center during the period of January, 1992 to December, 1997 were included in this study. Retrospectively, we reviewed medical records as to their clinical and labaratory data. RESULTS:Thyroid function status at initial diagnosis of Hashimoto's thyroiditis were euthyroidism(33.3%), compensatory hypothyroidism(33.3%), overt hypothyroidism (27.1%), hyperthyroidism(8.3%) in order. Positivity of antithyroglobulin antibodies and antimicrosomal antibodies were 77.1% and 66.7% respectively. In 33 patients, 12(36.4 %) were on remission status after 3 years from initial diagnosis. Antithyroglobulin antibody titer was significantly decreased after 2-year follow up in remission group. Initial antithyroglobulin antibody titer and thyroid function status were not related to remission status after 3-year from diagnosis. CONCLUSION: About 36% of patients with Hashimoto's thyroiditis can be in remission after 3-year from diagnosis. Decrease of antithyroglobulin antibody titer is related to remission status. Further study is necessary to know what can be the predicting factors for early remission, for example, initial thyroid function status, initial antithyroid antibody titier, circulating immune complex, age, sex and size of thyroid.
Adolescent ; Antibodies ; Antigen-Antibody Complex ; Biomarkers ; Child ; Chungcheongnam-do ; Diagnosis ; Follow-Up Studies ; Goiter ; Humans ; Hypothyroidism ; Medical Records ; Pediatrics ; Retrospective Studies ; Thyroid Gland* ; Thyroiditis*

PURPOSE:Craniopharyngioma is one of the most important intracranial tumors in pediatric age which causes multiple pituitary hormone deficiencies. We have studied clinical characteristics in patients with craniopharyngioma, focusing on changes of endocrine function, change of growth pattern, and change of body mass index before and after surgery. In addition, we wanted to know the effect of growth hormone therapy on growth velocity and body mass index, and to identify contributing factors for spontaneous growth in spite of growth hormone deficiency. METHODS:A total number of 17 patients who were diagnosed as having craniopharyngioma at the Department of Pediatrics, Asan Medical Center during the period of January, 1991 to December, 1997 were included in this study. Retrospectively, we reviwed medical records as to their endocrine function tests and auxoloogical data before, after surgery. RESULTS: 1)The number of patients of male and female were 9 and 8 respectively. Mean age was 7.3+/-4.3 years. 2)Preoperatively, 3 patients were thyroid hormone deficient, 3 patients were corticosteroid deficient, and 3 patients suffered from diabetes inspidus. 3)Postoperatively, GH and TSH deficiency were found in 100%, ACTH in 88.2%, ADH in 82.3%, and LH/FSH in 60%, 53% respectively. 4) Mean growth velocity in 14 GH deficient patients without growth hormone treatment for 2 years were 3.5+/-2.4cm/year during the 1st year and 3.1+/-1.7cm/year during the 2nd year. Although height standard deviation score(Ht. SDS) was decreasing trend as -0.24+/-2.19 at diagnosis, -0.94+/-1.73 at 1 year later, and -0.76+/-1.76 at 2 years later, it was not statistically significant. To our suprise, 4 out of 14 patients achieved greater growth velocity than nomal in spite of growth hormone deficiency during the 1st year after operation. 5) Although the mean body mass index of 14 GH deficient patients without GH treatment was increasing trend as 17.9+/-3.5 at diagnosis, 19.0+/-4.5 at 1 year later, and 19.9+/-4.8 at 2 year later, it was not statistically significant. 6) The mean Ht. SDS increased significantly in 7 patients treated with growth hormone(P<0.05) for 2 years, but change of body mass index was not significant. 7) Comparision of postoperative serum prolactin levels and changes of body mass index between spontaneous growth and stunted growth group did not reveal significant difference. CONCLUSION: Since most patients with craniopharyngioma become multiple pituitary hormone deficient after operation, it is important to predict and detect pituitary dysfunction to manage it effectively. Although patients with postoperative GH deficiency responded well to GH treatment, further study is needed to clarify what are the main contributing or prognostic factors for spontaneous growth without growth hormone treatment.
Adrenocorticotropic Hormone ; Body Mass Index ; Chungcheongnam-do ; Craniopharyngioma* ; Diagnosis ; Female ; Growth Hormone ; Humans ; Male ; Medical Records ; Obesity ; Pediatrics ; Prolactin ; Retrospective Studies ; Thyroid Gland