512 research outputs found
Psoas Abscess Caused by Spontaneous Rupture of Colon Cancer
Spontaneous rupture of colon cancer, combined with psoas abscess formation, is rare. A 44-year-old male visited for back pain and left buttock mass. Abdominal computed tomography and magnetic resonance image revealed a large abscess in the left psoas muscle and in the left lower quadrant area. Ten days after incision and drainage, a skin defect around the left anterior superior iliac spine remained. A local flap was performed using a superficial skin graft. Ten days after the stitches had been removed, fecal discharge was observed around the anterior superior iliac spine at the flap site. An operation was performed by a general surgeon who had diagnosed this as a case of enterocutaneous fistula. Operative findings included a ruptured tumor mass in the descending colon, which was connected to a retroperitoneal abscess. Pathologic report findings determined adenocarcinoma of the resected colon. Herein, we report a case of psoas abscess resulting from perforating colon cancer
OASIS: Online Application for the Survival Analysis of Lifespan Assays Performed in Aging Research
Aging is a fundamental biological process. Characterization of genetic and environmental factors that influence lifespan is a crucial step toward understanding the mechanisms of aging at the organism level. To capture the different effects of genetic and environmental factors on lifespan, appropriate statistical analyses are needed.We developed an online application for survival analysis (OASIS) that helps conduct various novel statistical tasks involved in analyzing survival data in a user-friendly manner. OASIS provides standard survival analysis results including Kaplan-Meier estimates and mean/median survival time by taking censored survival data. OASIS also provides various statistical tests including comparison of mean survival time, overall survival curve, and survival rate at specific time point. To visualize survival data, OASIS generates survival and log cumulative hazard plots that enable researchers to easily interpret their experimental results. Furthermore, we provide statistical methods that can analyze variances among survival datasets. In addition, users can analyze proportional effects of risk factors on survival.OASIS provides a platform that is essential to facilitate efficient statistical analyses of survival data in the field of aging research. Web application and a detailed description of algorithms are accessible from http://sbi.postech.ac.kr/oasis
Quantitative Understanding of Probabilistic Behavior of Living Cells Operated by Vibrant Intracellular Networks
For quantitative understanding of probabilistic behaviors of living cells, it is essential to construct a correct mathematical description of intracellular networks interacting with complex cell environments, which has been a formidable task. Here, we present a novel model and stochastic kinetics for an intracellular network interacting with hidden cell environments, employing a complete description of cell state dynamics and its coupling to the system network. Our analysis reveals that various environmental effects on the product number fluctuation of intracellular reaction networks can be collectively characterized by Laplace transform of the time-correlation function of the product creation rate fluctuation with the Laplace variable being the product decay rate. On the basis of the latter result, we propose an efficient method for quantitative analysis of the chemical fluctuation produced by intracellular networks coupled to hidden cell environments. By applying the present approach to the gene expression network, we obtain simple analytic results for the gene expression variability and the environment-induced correlations between the expression levels of mutually noninteracting genes. The theoretical results compose a unified framework for quantitative understanding of various gene expression statistics observed across a number of different systems with a small number of adjustable parameters with clear physical meanings.National Research Foundation of Korea (Grant 2011-0016412)National Research Foundation of Korea (Priority Research Center Program 2009-0093817
Changes in activity and isozyme patterns of peroxidase and chitinase in kiwifruit pollen
In this study, changes in activity and isozyme patterns of peroxidase (POD) and chitinase in kiwifruit (Actinidia chinensis) pollen were investigated under different storage conditions. Although residual activity was detected in heat-treated pollen, changes in POD activity were observed due to difference in storage conditions as revealed by preliminary studies in which pollen germination varied with different storage conditions. POD activity of kiwifruit pollen increased as proportions of viable pollen increased, indicating a positive correlation (R2=0.993) between pollen viability and POD activity. There was a detectable difference in the relative activity of POD enzyme between heat-treated and viable pollen. Decoloration of Congo Red was observed in germination medium which fresh pollen was cultured. The activity of individual chitinase isozymes present in kiwifruit pollen differed depending on storage conditions, which had a direct impact on pollen vigor. Although direct evidence showing that chitinase isozymes are implicated in pollen vigor is still uncertain, distinction of isozymes may facilitate more precise identification of viable pollen which possesses germination potential from non-viable pollen. Taken together, these results suggest that monitoring the activity of POD and chitinase can be an attractive alternative to evaluate pollen vigor in kiwifruit
Bioconversion of CO to formate by artificially designed carbon monoxide:formate oxidoreductase in hyperthermophilic archaea
Ferredoxin-dependent metabolic engineering of electron transfer circuits has been developed to enhance redox efficiency in the field of synthetic biology, e.g., for hydrogen production and for reduction of flavoproteins or NAD(P)+. Here, we present the bioconversion of carbon monoxide (CO) gas to formate via a synthetic CO:formate oxidoreductase (CFOR), designed as an enzyme complex for direct electron transfer between non-interacting CO dehydrogenase and formate dehydrogenase using an electron-transferring Fe-S fusion protein. The CFOR-introduced Thermococcus onnurineus mutant strains showed CO-dependent formate production in vivo and in vitro. The maximum formate production rate from purified CFOR complex and specific formate productivity from the bioreactor were 2.2????????0.2 ??mol/mg/min and 73.1????????29.0 mmol/g-cells/h, respectively. The CO-dependent CO2 reduction/formate production activity of synthetic CFOR was confirmed, indicating that direct electron transfer between two unrelated dehydrogenases was feasible via mediation of the FeS-FeS fusion protein
Fabrication and evaluation of bilateral Helmholtz radiofrequency coil for thermo-stable breast image with reduced artifacts
PURPOSE: The positron emission tomography (PET)-magnetic resonance (MR) system is a newly emerging technique that yields hybrid images with high-resolution anatomical and metabolic information. With PET-MR imaging, a definitive diagnosis of breast abnormalities will be possible with high spatial accuracy and images will be acquired for the optimal fusion of anatomic locations. Therefore, we propose a PET-compatible two-channel breast MR coil with minimal disturbance to image acquisition which can be used for simultaneous PET-MR imaging in patients with breast cancer.
MATERIALS AND METHODS: For coil design and construction, the conductor loops of the Helmholtz coil were tuned, matched, and subdivided with nonmagnetic components. Element values were optimized with an electromagnetic field simulation. Images were acquired on a GE 600 PET-computed tomography (CT) and GE 3.0 T MR system. For this study, we used the T1-weighted image (volunteer; repetition time (TR), 694 ms; echo time (TE), 9.6 ms) and T2-weighted image (phantom; TR, 8742 ms; TE, 104 ms) with the fast spin-echo sequence.
RESULTS: The results of measuring image factors with the proposed radiofrequency (RF) coil and standard conventional RF coil were as follows: signal-to-noise ratio (breast; 207.7 vs. 175.2), percent image uniformity (phantom; 89.22%-91.27% vs. 94.63%-94.77%), and Hounsfield units (phantom; -4.51 vs. 2.38).
CONCLUSIONS: Our study focused on the feasibility of proposed two-channel Helmholtz loops (by minimizing metallic components and soldering) for PET-MR imaging and found the comparable image quality to the standard conventional coil. We believe our work will help significantly to improve image quality with the development of a less metallic breast MR coil
Inferior vena cava filter insertion through the popliteal vein: enabling the percutaneous endovenous intervention of deep vein thrombosis with a single venous access approach in a single session
PURPOSE:We aimed to evaluate the efficiency of placing an inferior vena cava (IVC) filter through the same popliteal vein access site used for percutaneous endovenous intervention in patients with extensive lower extremity deep vein thrombosis.METHODS:This retrospective study included 21 patients who underwent IVC filter insertion through the popliteal vein over a three-year period. Patient medical records were reviewed for the location of the deep vein thrombosis, result of filter removal, and total number of endovascular procedures needed for filter insertion and recanalization of the lower extremity venous system. Follow-up lower extremity computed tomography (CT) venography was also reviewed in each patient to assess the degree of filter tilt in the IVC.RESULTS:All patients had extensive lower extremity deep vein thrombosis involving the iliac vein and/or femoral vein. Seventeen patients showed deep vein thrombosis of the calf veins. In all patients, IVC filter insertion and the recanalization procedure were performed during a single procedure through the single popliteal vein access site. In the 17 patients undergoing follow-up CT, the mean tilt angle of the filter was 7.14°±4.48° in the coronal plane and 8.77°±5.49° in the sagittal plane. Filter retrieval was successful in 16 of 17 patients (94.1%) in whom filter retrieval was attempted.CONCLUSION:Transpopliteal IVC filter insertion is an efficient technique that results in low rates of significant filter tilt and enables a single session procedure using a single venous access site for filter insertion and percutaneous endovenous intervention
Endovascular treatment of wide-necked aneurysms of the visceral and renal arteries using the double microcatheter technique via a single access route
PURPOSEWe aimed to evaluate the utility of and complications associated with the double microcatheter technique for the treatment of wide-necked visceral and renal artery aneurysms (VRAAs).METHODSNine patients (mean age, 58 years; age range, 42–69 years; 4 men, 5 women) with wide-necked VRAAs who underwent treatment with the double microcatheter technique from January 2016 to July 2018 were included in the study. For all patients, anatomical features were confirmed using cone-beam computed tomography (CT) with rotational angiography. The aneurysmal location, size, volume, neck-to-dome ratio, number of coils used, and coil packing density were investigated. Technical success, complications (coil migration and organ ischemia), changes in the complete blood count or serum creatine level, and recurrence were also evaluated.RESULTSThree renal artery aneurysms and 6 splenic artery aneurysms were treated by the double microcatheter technique. The mean size of the aneurysms was 26.09±4.76 mm, mean volume was 6.19±3.69 cm3, and mean neck-to-dome ratio was 1.53±0.24. The number of coils used ranged from 7 to 16. The mean packing density was 11.32%±3.72%. Technical success was achieved in all 9 patients. Renal ischemia occurred in two patients with renal artery aneurysm, one of whom showed minimal scar formation on follow-up CT after infarction. No coil migrations or disease recurrences were observed.CONCLUSIONThe double microcatheter technique for the treatment of wide-necked VRAAs appears to be relatively safe and useful. However, complex renal artery aneurysm should be carefully managed in order to prevent infarction
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AKAP12 Mediates Barrier Functions of Fibrotic Scars during CNS Repair
The repair process after CNS injury shows a well-organized cascade of three distinct stages: inflammation, new tissue formation, and remodeling. In the new tissue formation stage, various cells migrate and form the fibrotic scar surrounding the lesion site. The fibrotic scar is known as an obstacle for axonal regeneration in the remodeling stage. However, the role of the fibrotic scar in the new tissue formation stage remains largely unknown. We found that the number of A-kinase anchoring protein 12 (AKAP12)-positive cells in the fibrotic scar was increased over time, and the cells formed a structure which traps various immune cells. Furthermore, the AKAP12-positive cells strongly express junction proteins which enable the structure to function as a physical barrier. In in vivo validation, AKAP12 knock-out (KO) mice showed leakage from a lesion, resulting from an impaired structure with the loss of the junction complex. Consistently, focal brain injury in the AKAP12 KO mice led to extended inflammation and more severe tissue damage compared to the wild type (WT) mice. Accordingly, our results suggest that AKAP12-positive cells in the fibrotic scar may restrict excessive inflammation, demonstrating certain mechanisms that could underlie the beneficial actions of the fibrotic scar in the new tissue formation stage during the CNS repair process
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