Cilostazol is used for the treatment of intermittent claudication, ulceration and pain. This study was conducted to develop a population pharmacodynamic (PD) model for cilostazol's closure time (CT) prolongation effect in healthy Korean subjects based on a pharmacokinetic (PK) model previously developed. PD data were obtained from 29 healthy subjects who participated in a study conducted in 2009 at Severance Hospital. The PK model used was a two-compartment model with first order absorption. CT data were best described by a turnover model with a fractional turnover rate constant (K(out)) inhibited by drug effects (Eff), which were represented by a sigmoid E(max) model [Eff = E(max) · C(γ) / (EC₅₀(γ)+C(γ))] with E(max) being maximum drug effect, EC₅₀ drug plasma concentration at 50% of E(max), C drug plasma concentrations, and γ the Hill coefficient. For the selected PD model, parameter estimates were 0.613 hr⁻¹ for K(out), 0.192 for E(max), 730 ng/ml for EC₅₀ and 5.137 for γ. Sex and caffeine drinking status significantly influenced the baseline CT, which was 85.36 seconds in male non-caffeine drinkers and increased by 15.5% and 16.4% in females and caffeine drinkers, respectively. The model adequately described the time course of CT. This was the first population PD study for cilostazol's CT prolongation effect in a Korean population.
Absorption ; Caffeine ; Colon, Sigmoid ; Drinking ; Female ; Healthy Volunteers ; Humans ; Intermittent Claudication ; Male ; Plasma ; Ulcer

Pneumothorax, pneumomediastinum and pneumopericardium usually develop during emergency situations and these conditions may result in cardiopulmonary compromise, so an early and accurate diagnosis is seen as crucial for proper treatment. For diagnosis of pneumothorax, pneumomediastinum and pneumopericardium, chest radiography is a primary modality and CT can help for diagnosing them earlier and detecting associated abnormalities. The purpose of this pictorial essay is to describe the pathophysiology, various radiographic signs and diagnostic pitfalls of pneumothorax, pneumomediastinum and peumopericardium on chest radiographs that are correlated with CTs, and to aid the physician in the radiographic diagnosis.
Diagnosis ; Emergencies ; Mediastinal Emphysema* ; Pneumopericardium* ; Pneumothorax* ; Radiography ; Radiography, Thoracic ; Thorax

A trocar site hernia is a rare complication. We report a patient who had an abdominal wall mass at a previous trocar site after laparoscopic distal gastrectomy. It was diagnosed as omental herniation and fat necrosis. We conclude that patients with trocar site masses exhibiting fat density on a computed tomography scan could be followed up without surgery, and that fascial defects located at 10-mm or larger trocar sites should be closed whenever possible to prevent hernia formation.
Abdominal Wall ; Fat Necrosis ; Gastrectomy ; Hernia ; Humans ; Laparoscopy ; Omentum ; Stomach Neoplasms ; Surgical Instruments

PURPOSE: To evaluate the NMR relaxation properties and imaging characteristics of tissue-specificity for a newly developed macromolecular MR agent. MATERIALS AND METHODS: Phthalocyanine (PC) was chelated with paramagnetic ion, Mn. 2.01g(5.2 mmol) of Phthalocyanine was mixed with 0.37g (1.4 mmol) of Mn chloride at 310 degrees C for 36 hours and then purified by chromatography (CHC13/CH3OH 98/2 v/v, Rf, 0.76) to obtain 1.04g (46%) of MnPC (molecular weight = 2000d), The T1/T2 relaxivity of MnPC was measured in 1.5T(64 MHz) MR using 0.1 mM MnPC. The MR image characteristics of MnPC was evaluated using spin-echo (TR/TE = 500/14 msec) and gradient-echo (FLASH) (TR/TE = 80/4 msec, flip angle = 60) techniques in 1.5T MR scanner. The images of rabbit liver were obtained every 10 minutes up to 4 hours. To study the effect of concentration on image, 20 mM, 50 mM, 100 mM of MnPC were tested. RESULTS: The relaxivities of MnPC at 1.5T (64MHz) were R1 = 7.28 mM-1S-1, R2 = 55.56 mM-1S-1. Compared to the values of Gd-DTPA (R1[= 4.8 mM-1S-1), R2[= 5.2 mM-1S-1]), both T1/T2 relaxivities of MnPC were higher than those of Gd-DTPA. For both of SE and FLASH techniques, the contrast enhancement reached maximum at 10 minutes after bolus injection and the enhancement continued for more than 2 hours. When compared with small molecular weight liver agents such as Gd-EOB-DTPA, Gd-BOPTA and MnDPDP, MnPC was characterized by more prolonged enhancement time. The time course of MR images also revealed biliary excretion of MnPC. CONCLUSION: We developed a new macromolecular MR agent, MnPC. The relaxivities of MnPC were higher than those of small molecular weight Gd-chelate. Hepatic uptake and biliary excretion of MnPC suggests that this agent is a new liver-specific MR agent.
Chromatography ; Gadolinium DTPA ; Liver ; Molecular Weight ; Relaxation

Objective: To investigate the clinical feasibility of synthetic diffusion-weighted imaging (sDWI) at different b-values in patientswith breast cancer by assessing the diagnostic image quality and the quantitative measurements compared with conventionaldiffusion-weighted imaging (cDWI). Materials and Methods: Fifty patients with breast cancer were assessed using cDWI at b-values of 800 and 1500 s/mm2 (cDWI800and cDWI1500) and sDWI at b-values of 1000 and 1500 s/mm2 (sDWI1000 and sDWI1500). Qualitative analysis (normal glandulartissue suppression, overall image quality, and lesion conspicuity) was performed using a 4-point Likert-scale for all DWI setsand the cancer detection rate (CDR) was calculated. We also evaluated cancer-to-parenchyma contrast ratios for each DWI setin 45 patients with the lesion identified on any of the DWI sets. Statistical comparisons were performed using Friedman test,one-way analysis of variance, and Cochran’s Q test. Results: All parameters of qualitative analysis, cancer-to-parenchyma contrast ratios, and CDR increased with increasingb-values, regardless of the type of imaging (synthetic or conventional) (p< 0.001). Additionally, sDWI1500 provided better lesionconspicuity than cDWI1500 (3.52 ± 0.92 vs. 3.39 ± 0.90, p< 0.05). Although cDWI1500 showed better normal glandular tissuesuppression and overall image quality than sDWI1500 (3.66 ± 0.78 and 3.73 ± 0.62 vs. 3.32 ± 0.90 and 3.35 ± 0.81, respectively;p< 0.05), there was no significant difference in their CDR (90.0%). Cancer-to-parenchyma contrast ratios were greater insDWI1500 than in cDWI1500 (0.63 ± 0.17 vs. 0.55 ± 0.18, p< 0.001). Conclusion sDWI1500 can be feasible for evaluating breast cancers in clinical practice. It provides higher tumor conspicuity,better cancer-to-parenchyma contrast ratio, and comparable CDR when compared with cDWI1500.

OBJECTIVE: Clear depiction of the common bile duct is important when evaluating neonatal cholestasis in order to differentiate biliary atresia from other diseases. During MR cholangiopancreatography, the T2-shortening effect of gadolinium can increase the contrast-to-noise ratio (CNR) of the bile duct and enhance its depiction. The purpose of this study was to confirm, by performing a phantom study, the T2-shortening effect of gadolinium, to evaluate the effect of different gadolinium chelates with different gadolinium concentrations and different magnetic field strengths for investigating the optimal combination of these conditions, and for identifying the maximum CNR for the evaluation of the biliary system. MATERIALS AND METHODS: MR imaging using a T2-weighted single-shot fast spin echo sequence and T2 relaxometry was performed with a sponge phantom in a syringe tube. Two kinds of contrast agents (Gd-DTPA and Gd-EOB-DTPA) with different gadolinium concentrations were evaluated with 1.5T and 3T scanners. The signal intensities, the CNRs and the T2 relaxation time were analyzed. RESULTS: The signal intensities significantly decreased as the gadolinium concentrations increased (p < 0.001) with both contrast agents. These signal intensities were higher on a 3T (p < 0.001) scanner. The CNRs were higher on a 1.5T (p < 0.001) scanner and they showed no significant change with different gadolinium concentrations. The T2 relaxation time also showed a negative correlation with the gadolinium concentrations (p < 0.001) and the CNRs showed decrease more with Gd-EOB-DTPA (versus Gd-DTPA; p < 0.001) on a 3T scanner (versus 1.5T; p < 0.001). CONCLUSION: A T2-shortening effect of gadolinium exhibits a negative correlation with the gadolinium concentration for both the signal intensities and the T2 relaxation time. A higher CNR can be obtained with Gd-DTPA on a 1.5T MRI scanner.
Analysis of Variance ; Biliary Atresia/diagnosis ; Cholangiopancreatography, Magnetic Resonance/*methods ; Cholestasis/diagnosis ; Contrast Media/*administration & dosage/diagnostic use ; Diagnosis, Differential ; Gadolinium DTPA/*administration & dosage/diagnostic use ; Humans ; Image Processing, Computer-Assisted ; Linear Models ; *Phantoms, Imaging

PURPOSE: The aims of this study were to evaluate the safety and pharmacokinetics of levetiracetam (LEV) in neonates with seizures and to establish a population pharmacokinetics (PPK) model by using the software NONMEM. METHODS: A retrospective analysis of 18 neonatal patients with seizures, who were treated with LEV, including 151 serum samples, was performed. The mean loading dose was 20 mg/kg, followed by a mean maintenance dose of 29 mg/kg/day. RESULTS: Seventeen neonates (94%) had seizure cessation within 1 week and 16 (84%) remained seizure-free at 30 days under the LEV therapy. The mean serum concentration of LEV was 8.7 µg/mL. Eight samples (5%) were found above the therapeutic range. No serious adverse effects were detected. In the PPK analysis for Korean neonates, the half-life was 9.6 hours; clearance, 0.357 L/hr; and volume of distribution, 4.947 L, showing differences from those in adults. CONCLUSION: LEV is a safe and effective option for the treatment of neonatal seizures with careful therapeutic drug monitoring.
Adult ; Drug Monitoring ; Half-Life ; Humans ; Infant, Newborn* ; Pharmacokinetics* ; Retrospective Studies ; Seizures*

Purpose: The purpose of this study was to investigate the concordance rate of PIK3CA mutations between primary and matched distant metastatic sites in patients with breast cancer and to verify whether there are differences in the frequency of PIK3CA hotspot mutations depending on the metastatic sites involved. Materials and Methods: Archived formalin-fixed paraffin-embedded (FFPE) specimens of primary breast and matched distant metastatic tumors were retrospectively obtained for 49 patients. Additionally, 40 archived FFPE specimens were independently collected from different breast cancer metastatic sites, which were limited to three common sites: the liver, brain, and lung. PIK3CA mutations were analyzed using droplet digital PCR, including hotspots involving exons 9 and 20. Results: After analysis of 49 breast tumors with matched metastasis sites, 87.8% showed concordance in PIK3CA mutation status. According to PIK3CA hotspot mutation testing in 89 cases of breast cancer metastatic sites, the proportion of PIK3CA mutations at sites of metastasis involving the liver, brain, and lung was 37.5%, 28.6%, and 42.9%, respectively, which did not result in statistical significance. Conclusion The high concordance of PIK3CA mutation status between primary and matched metastasis sites suggests that metastatic sites, regardless of the metastatic organ, could be considered sample sources for PIK3CA mutation testing for improved therapeutic strategies in patients with metastatic breast cancer.

PURPOSE: Before laparoscopic gastrectomy for gastric cancer can be planned, it is very important to know the precise location of the tumor. The aim of this study was to evaluate 3 methods of predicting the exact location of the tumor: preoperative gastrofibroscopy (GFS), preoperative computed tomography gastroscopy (CT), and intraoperative gastroscopy-guided laparoscopy (Lap). METHODS: In this study, 15 patients were prospectively identified, and endoscopic clips were preoperatively placed on the proximal 1 cm of the tumor, at the angle on the greater curvature and opposite the angle on the greater curvature. The distances between the pylorus and the proximal tumor clip (PT), the angle clip (PA), the greater curvature clip (PG), and the gastroesophageal junction were measured by preoperative GFS, preoperative CT, intraoperative Lap, and visual inspection (Vis). RESULTS: PT, PA, and PG values measured by preoperative GFS differed significantly from the Vis values (P < 0.01). However, preoperative CT measurements of PT, PA, and PG did not differ from the Vis values (P = 0.78, P = 0.48, and P = 0.53, respectively). Intraoperative Lap and Vis PT values differed by only 1.1 cm on an average (P = 0.10), but PA and PG values varied by 1.9 and 3.4 cm, respectively (P = 0.01 for both). CONCLUSION: Endoscopic clipping combined with preoperative CT gastroscopy is more useful than preoperative GFS for preoperatively predicting the location of early gastric cancers and will be helpful for planning laparoscopic gastrectomy.
Esophagogastric Junction ; Gastrectomy ; Gastroscopy ; Humans ; Laparoscopy ; Prospective Studies ; Pylorus ; Stomach Neoplasms ; Tomography, X-Ray Computed

Intussusception is rare in adults accounting for 5% of all cases. It can be caused by various lesions but is rarely the result of trauma. Recently we encountered a case of adult intussusception after blunt abdominal trauma without any other leading causes. We report this case with a review of the relevant literatures.
Abdomen, Acute ; Adult* ; Humans ; Intussusception*