• Journal of Korean Neurosurgical Society
• /
• v.29 no.11
• /
• pp.1437-1444
• /
• 2000

Objectives : Traditionally intracranial meningiomas are regarded as benign and curable tumors. About half of all intracranial meningiomas locate in the skull base region. However, surgical removal of these tumors may be challenging and require special considerations. Here general aspects of skull base meningiomas including clinical presentation, surgical approaches, complications and their recurrence rate are discussed based on our experiences. Methods : A retrospective analysis of 61 consecutive patients with skull base meningioma among 210 patients of meningioma between 1989 and 1998 were done. Results : There were 41 women and 20 men ranging from 13 to 74 years(mean 52 years). These tumors were divided into seven categories according to location : olfactory groove(n＝9), sphenoid ridge(n＝16), cavernous sinus(n ＝2), tuberculum sellae(n＝8), tentorium(n＝13), cerebellopontine angle(n＝12), and foramen magnum meningiomas (n＝1). Surgical approaches were selected on the basis of the tumor attachment, size and extension on preoperative radiologic findings. Total removal(Simpson grade I and II) was achieved in 50 cases(82%), and subtotal removal (Simpson grade III) in 11 patients(18%). According to WHO classification, there were 52 of cases of benign meningioma( 86%), 6 atypical cases(10%), and 3 malignant cases(5%). The most common postoperative complications were CSF leakage(23.0%) and cranial nerve injury(8.2%). Three patient died related with tumor(one was due to surgical complication and the other two due to recurrence) but three patients died from other systemic causes. Mean follow-up period was 51.7 months after surgery. Recurrence occurred in six patients(10.9%) ; three with tentorial meningioma, two with sphenoid ridge, and one in cerebellopontine angle. Conclusion : With advances in neuroradiology and microsurgical techniques, the surgical outcome of miningiomas has been markedly improved with acceptable morbidity and mortality rates. Overall, our surgical results of skull base meningiomas is comparable to other reports. Therefore, with the appropriate operative strategy and techniques, these tumors can be completely removed and good surgical results can be expected.

• Clinical and Experimental Pediatrics
• /
• v.45 no.2
• /
• pp.247-255
• /
• 2002

Purpose : This study was undertaken to obtain basic data about the megakaryocyte colony formation of fetal liver cells by using immunocytochemical staining and ex vivo culture with growth factors. Methods : The mononuclear cells were isolated from fetal liver and bone marrow with idiopathic thrombocytopenic purpura(ITP) and pancytopenia. These mononuclear cells were cultured in $MegaCult^{TM}-C$(Stem Cell Tech, Canada) media in the presence of growth factors and CFU-Megakaryocyte( CFU-Mk) colonies were counted on day 12. The expansion of CD34+ and CD41+ cell was analyzed by flow cytometry after 5 days incubation using flask culture. Results : The numbers of CFU-Mk colonies of mononuclear cells obtained from fetal liver in the 11th week gestational age were more than those in the 19th week specimens; growth factors could not enhance the colony expansion in all cases. Total numbers of CFU-Mk colony of fetal liver cells were higher than bone marrow from ITP or pancytopenia groups. The numbers of pure or large CFU-Mk colonies of fetal liver cells were also higher than bone marrow specimens. The rate of CD34+ cell expression of fetal liver was increased after flask culture and the enhancement effect of epression was seen only in cases which added thrombopoietin. The rate of CD41+ cell expression of fetal liver was increased after incubation, but the enhancement effect of growth factors was unclear. Conclusion : This study revealed good results about the megakaryocyte colony assay of fetal liver mononuclear cells using $MegaCult^{TM}-C$ media. This study suggests that the fetal liver could be a good source of megakaryocytic progenitor cells for clinical application in hematopoietic stem cell transplantation.

• Journal of Intelligence and Information Systems
• /
• v.17 no.4
• /
• pp.255-277
• /
• 2011

Product Service System(PSS), which is an integrated combination of product and service, provides new value to customer and makes companies sustainable as well. The objective of this paper draws Critical Successful Factors(CSF) of PSS through multiple case study. First, we review various concepts and types in PSS and Platform business literature currently available on this topic. Second, after investigating various cases with the characteristics of PSS and platform business, we select four cases of 'iPod of Apple', 'Kindle of Amazon', 'Zune of Microsoft', and 'e-book reader of Sony'. Then, the four cases are categorized as successful and failed cases according to criteria of case selection and PSS classification. We consider two methodologies for the case selection, i.e., 'Strategies for the Selection of Samples and Cases' proposed by Bent(2006) and the seven case selection procedures proposed by Jason and John(2008). For case selection, 'Stratified sample and Paradigmatic cases' is adopted as one of several options for sampling. Then, we use the seven case selection procedures such as 'typical', 'diverse', 'extreme', 'deviant', 'influential', 'most-similar', and 'mostdifferent' and among them only three procedures of 'diverse', 'most?similar', and 'most-different' are applied for the case selection. For PSS classification, the eight PSS types, suggested by Tukker(2004), of 'product related', 'advice and consulancy', 'product lease', 'product renting/sharing', 'product pooling', 'activity management', 'pay per service unit', 'functional result' are utilized. We categorize the four selected cases as a product oriented group because the cases not only sell a product, but also offer service needed during the use phase of the product. Then, we analyze the four cases by using cross-case pattern that Eisenhardt(1991) suggested. Eisenhardt(1991) argued that three processes are required for avoiding reaching premature or even false conclusion. The fist step includes selecting categories of dimensions and finding within-group similarities coupled with intergroup difference. In the second process, pairs of cases are selected and listed. The second step forces researchers to find the subtle similarities and differences between cases. The third process is to divide the data by data source. The result of cross-case pattern indicates that the similarities of iPod and Kindle as successful cases are convenient user interface, successful plarform strategy, and rich contents. The differences between the successful cases are that, wheares iPod has been recognized as the culture code, Kindle has implemented a low price as its main strategy. Meanwhile, the similarities of Zune and PRS series as failed cases are lack of sufficient applications and contents. The differences between the failed cases are that, wheares Zune adopted an undifferentiated strategy, PRS series conducted high-price strategy. From the analysis of the cases, we generate three hypotheses. The first hypothesis assumes that a successful PSS system requires convenient user interface. The second hypothesis assumes that a successful PSS system requires a reciprocal(win/win) business model. The third hypothesis assumes that a successful PSS system requires sufficient quantities of applications and contents. To verify the hypotheses, we uses the cross-matching (or pattern matching) methodology. The methodology matches three key words (user interface, reciprocal business model, contents) of the hypotheses to the previous papers related to PSS, digital contents, and Information System (IS). Finally, this paper suggests the three implications from analyzed results. A successful PSS system needs to provide differentiated value for customers such as convenient user interface, e.g., the simple design of iTunes (iPod) and the provision of connection to Kindle Store without any charge. A successful PSS system also requires a mutually benefitable business model as Apple and Amazon implement a policy that provides a reasonable proft sharing for third party. A successful PSS system requires sufficient quantities of applications and contents.

• Clinical and Experimental Pediatrics
• /
• v.46 no.10
• /
• pp.1003-1007
• /
• 2003

Purpose : To review the seizure-related complaints and analyze the relationship between admission rates and clinical features in children who had visited the emergency department with seizures. Methods : Retrospectively, we reviewed 180 patients(male 100, female 80) suffering from seizures, who had visited to the emergency department of Chosun University Hospital from January 2000 to June 2002. We have analyzed the correlation between admission rate and clinical features such as age, seizure type, seizure duration and individual laboratory findings(CT or MRI, and CSF). Results : Out of 4,865 total children who visited the emergency department, 180 patients(3.7%) were seizure related. The most common seizure type was simple febrile seizure(52.2%). The admission rate of children with seizures was 48.9%. The admission rate according to age, sex and abnormal laboratory findings revealed no significant correlations(P>0.05). There was a significant correlation between admission and both status epilepticus 82.4%(14/17) and complex febrile seizure 63.6%(14/22) (P<0.05). According to the duration of convulsions, admission rates were 41.2% when within five minutes, 60% when six-15 minutes, 58.8% when 16-30 minutes, 85.7% when 30 minutes, to one hour and 66.7% when above one hour of duration. According to the seizure frequency, admission rates of recurrent seizure patients(61.4%=43/70) was higher compared to the first time seizure patients(40.9%=45/110). Conclusion : We found that the admission rate of children visiting the emergency department for seizure treatment was 48.9% and significantly correlated with duration, type and frequency of seizure.

• Pediatric Infection and Vaccine
• /
• v.13 no.2
• /
• pp.130-136
• /
• 2006

Purpose : The purpose of this study is to confirm the epidemiologic change of the causative organisms of neonatal and pediatric bacterial meningitis in Korea. And we tried to evaluate the risk factors correlated with prognosis which was available on the day of admission. Methods : Retrospectively, we reviewed the medical records of 57 patients admitted for bacterial meningitis at six hospitals affiliated with Catholic Medical Center for 6 years(Jan. 2000~Dec. 2005). Results : 22 cases(38.6%) of them were neonates under 28 days and 35 cases were infants and children ; 16 cases(28.1%), under 1 year ; 6 cases(10.5%), under 5 years ; 13 cases (22.8%), under 15 years. In neonates, 16 cases(72.7%) were caused by group B streptococcus (GBS). In infants and children, S. pneumoniae(25.7%), H. influenzae type b(Hib)(22.8%) and N. meningitidis(22.8%) were common cause of bacterial meningitis in order. In the informations available on the day of admission, weight deficit for age under 3 percentile, increased CRP level and decreased glucose level of CSF were related to poor prognosis(P<0.05). Conclusion : GBS became a leading cause of neonatal bacterial meningitis. Though, pneumoccocal, Hib and meningococcal meningitis were confirmed as major causes of bacterial meningitis. The routine immunization of pneumococcal and Hib vaccines will be considered, and it is necessary to introduce meningococcal vaccines to our country in the future.

• The Korean Journal of Nuclear Medicine
• /
• v.32 no.6
• /
• pp.490-496
• /
• 1998

Purpose: We evaluated brain perfusion SPECT findings of MELAS syndrome and mitochondrial myopathy in correlation with MR imaging in search of specific imaging features. Materials and Methods: Subjects were five patients (four females and one male; age range, 1 to 25 year) who presented with repeated stroke-like episodes, seizures or developmental delay or asymptomatic but had elevated lactic acid in CSF and serum. Conventional non-contrast MR imaging and Tc-99m-ethyl cysteinate dimer (ECD) brain perfusion SPECT were Performed and imaging features were analyzed. Results: MRI demonstrated increased T2 signal intensities in the affected areas of gray and white matters mainly in the parietal (4/5) and occipital lobes (4/5) and in the basal ganglia (1/5), which were not restricted to a specific vascular territory. SPECT demonstrated decreased perfusion in the corresponding regions of MRI lesions. In addition, there were perfusion defects in parietal (1 patient), temporal (2), and frontal (1) lobes and basal ganglia (1) and thalami (2). In a patient with mitochondrial myopathy who had normal MRI, decreased perfusion was noted in left parietal area and bilateral thalami. Conclusion: Tc-99m ECD SPECT imaging in patients with MELAS syndrome and mitochondrial myopathy showed hypoperfusion of parieto-occipital cortex, basal ganglia, thalamus and temporal cortex, which were not restricted to a specific vascular territory. There were no specific imaging features on SPECT. The significance of abnormal perfusion on SPECT without corresponding MR abnormalities needs to be evaluated further in larger number of patients.

• Clinical and Experimental Pediatrics
• /
• v.51 no.10
• /
• pp.1077-1084
• /
• 2008

Purpose : Despite the seriousness of bacterial meningitis in children, there is little information on the incidence, causative organisms, mortality rate and age distribution. We studied the frequency by age group and causal pathogens, and clinical characteristics in children with bacterial meningitis in the private sector in Korea. Methods : The medical records containing the data on bacterial meningitis patients under 18 years of age confirmed by cerebrospinal fluid (CSF) findings were retrospectively analyzed from September, 1993 to August, 2006 at Ewha Womans University Mokdong Hospital. Results : Eighty-one cases of bacterial meningitis were observed. Overall the most common organism was Streptococcus agalactiae (group B streptococcus, GBS) (30 cases, 37.0%) followed by Haemophilus influenzae (22 cases, 27.2%), Streptococcus pneumoniae (12 cases, 14.8%), Escherichia coli (3 cases, 3.7%), Neisseria meningitidis (1 case, 1.2%) and others (13 cases, 16.0%). In neonates and young infants under 2 months, the most common organism was GBS. In children between 3 months, and 5 years, the most common organism was H. influenzae. S. pneumoniae was the most common organism in children over 5 years of age. Thirty-one patients (38.3%) had complications. Of all ages, the mortality rate of bacterial meningitis markedly decreased compared with the previously reported rate. Conclusion : In neonates, GBS meningitis was most common. The frequency of H. influenzae meningitis decreased after the introduction of H. influenzae type b vaccination. A strategy for the prevention of GBS meningitis in neonates should be established. The influence of the pneumococcal conjugate vaccine on S. pneumoniae meningitis should be studied.

• Clinical and Experimental Pediatrics
• /
• v.46 no.12
• /
• pp.1224-1229
• /
• 2003

Purpose : Bacterial meningitis is a serious disease, especially in the neonatal period, and it carries a significant degree of mortality and morbidity. Group B streptococcus(GBS) is a common cause of neonatal bacterial meningitis. The purpose of this study was to evaluate the clinical manifestations, treatment results and complications of GBS meningitis. Methods : We analyzed 29 cases retrospectively who had been admitted to the pediatric ward or NICU in Asan Medical Center from May 1990 to January 2002. They had proven GBS in culture or latex agglutination test in CSF. Results : The male to female ratio was 1 : 1.9. There were two cases of early onset type and 27 cases of late onset type. All cases had normal birth weight with full term at delivery. The perinatal predisposing factors were premature rupture of membrane(two cases), and maternal colonization(two cases). The most common presenting symptoms were fever and irritability. Associated diseases were GBS sepsis(21 cases). There was relatively high sensitivity to penicillin derivatives. There were abnormal brain CT or MRI findings in 16 cases(64%), such as infarction, encephalomalatic change, effusion, hydrocephalus, hemorrhage and abscess. The intensive care unit admission rate and the incidence of DIC were higher in the group with complications. Two cases were discharged against advice. Conclusion : We recommend early detection and active treatment in Group B streptococcal meningitis to improve the prognosis.

• Investigative Magnetic Resonance Imaging
• /
• v.4 no.1
• /
• pp.34-41
• /
• 2000

Purpose: To evaluate the clinical usefulness of diffusion weighted MR imaging(DWI) in the differential diagnosis of brain tumors. Materials and methods: DWI and conventional MR images of nineteen patients with brain tumors(10 metastatic tumors, 4 high grade gliomas, 4 low grade astrocytomas, one oligodendroglioma)were obtained on 1.5T unit. DWI was obtained using single shot spin echo planar imaging with b-value near 1000. We analyzed the signal intensities of lesions including solid portion, necrotic or cystic portion and peritumoral edema of brain tumors (classified five grades comparison with the signal intensities of brain parenchyma and CSF)and calculate the SIR(signal intensity ratio)of lesions to the contralateral normal brain parenchyma. We analyzed statistically the signal intensities and SIR of tumors using independence T test. Results: In solid portions of tumors, all the metastatic tumors and high grade gliomas showed high signal intensities, but low grade astrocytomas and oligodendroglioma showed iso or slight high signal intensities to the normal brain parenchyma. The SIR of solid portion has positive correlation with malignant pot ential(metastatic tumors 1.52, high grade gliomas 1.38, low grade astrocytomas 1.16, oligodendroglioma 1.31)(p < 0.05). In peritumoral edema where seen in 14 tumors, seven of 10 metastatic tumors and two of 4 high grade gliomas showed iso signal intensities, whereas edemas in other 5 brain tumors showed hyperintense to the normal brain parenchyma. The SIRs of peritumoral edemas in metastatic tumors (1.14) was lower than high grade gliomas(1.31),but statistically insignificant. The SIR of cystic or necrotic portion of brain tumors was 0.63. In non enhancing solid portions, three of six cases showed hyperintense to the adjacent peritumoral edema. Conclusion: On DWI, the signal intensities of solid portion has positive correlation with malignant potential, and perilesional edema of brain tumors appear various signal intensities owing to "T2 shine through effect" and the extensiveness of vasogenic edema. Another merit using DWI on the evaluation of brain tumors is to improved better delineation of tumor margins from the adjacent edemas, especially at the non enhancing solid portion of the tumors.

• Tuberculosis and Respiratory Diseases
• /
• v.46 no.1
• /
• pp.44-52
• /
• 1999

Background : Airway infiltration by inflammatory cells, particularly of eosinophils, is one of the characteristic features of asthma. Several mechanisms for the recruitment of eosinophil is focused on the CD4+ T lymphocyte for the preferential production of Th2-c1erived cytokines. Interleukin-10(IL-10) is identified cytokine with potent antiinflammatory activity. This molecule has been shown to inhibit the release of cytokine from inflammatory cells including Th2 cell, and also to inhibit eosinophil survival. We therefore attempted to determine whether decreased synthesis of IL-10 in the lung of bronchial asthma may contribute to inflammation that is characteristics of this dease. Method: Subjects were patients with bronchial asthma(n=23) and normal controls(n=11). IL-10 produced from peripheral mononuclear cell(PBMC) and in bronchoalveolar lavage(BAL) fluid was measured by ELISA method. Degree of bronchial inflammation was assessed by total cell counts and eosinophil percents in BAL fluid, eosinophil infiltration on bronchial biopsy tissue and $PC_{20}$ for methacholine. Results: The IL-10 level produced by PBMC and in BAL fluid from patient with bronchial asthma were not different with normal controls(respectively, $901.6\pm220.4$ pg/ml, $810.9\pm290.8$ pg/ml for PBMC, $24.5\pm9.5$ pg/mL $30.5\pm13.5$ pg/ml for BAL fluid p>0.05). There were significant negative correlation between IL-10 in BAL fluid and eosinophil percents in BAL fluid or degree of eosinophil infiltration in bronchial biopsy (respectively r=-0.522, r=-0.4486 p<0.05). However there was no difference of IL-10 level according to $PC_{20}$ for methacholine. There were no correlation between IL-10 production by PBMC and peripheral blood eosinophil counts or serum eosinophilic cationic protein levels(respectively r=0.1146, r=0.0769 p>0.05). Conclusion: These observation suggest that IL-10 may participate but not acts the crucial role in regulation of the airway inflammation in bronchial asthma.