Mechanismen der Mitogen-aktivierten-Proteinkinase (MAPK)-Aktivierung in der Pankreasazinuskarzinom-Zelllinie AR42J

Die Aktivierung der Mitogen-aktivierten Proteinkinase (MAPK) spielt eine Schlüsselrolle in der Vermittlung proliferativer Effekte sowohl von Rezeptoren vom Tyrosinkinase-Typ (RTK) wie dem epidermalen Wachstumsfaktor-Rezeptor (EGFR), als auch von G-Protein gekoppelten Rezeptoren (GPCR). Die MAPK-Aktivierungsmechanismen durch GPCR sind im Gegensatz zum EGFR unzureichend verstanden und stark von Rezeptor- und Zelltyp abhängig. Ziel dieser Arbeit war die nähere Charakterisierung der Signaltransduktion des GPCR-zugehörigen Cholezystokinin (CCK)-Rezeptors bezüglich der Aktivierung der MAPK durch Western-Blot-Analysen in der Pankreasazinus-Karzinomzelllinie AR42J der Ratte. Die Ergebnisse zeigen eine Beteiligung des EGFR im Mechanismus der CCK-induzierten MAPK-Aktivierung mittels einer EGFR-Transaktivierung. Diese ist mit einer Tyrosinphosphorylierung des EGFR und von Shc sowie einer Komplexbildung der Adapterproteine Shc und Grb2 mit dem EGFR verbunden. Diese Vorgänge sind von der intrinsischen Tyrosinkinaseaktivität des EGFR abhängig. Neben dem EGFR konnte durch weitere Untersuchungen eine Aktivierung und Beteiligung von Tyrosinkinasen der Src-Familie (SFTK) an der CCK-induzierten MAPK-Aktivierung gezeigt werden. Dabei stellte sich heraus, dass die CCK-induzierte Shc-Tyrosinphosphorylierung und die EGFR-Shc-Grb2-Komplexbildung im Rahmen der EGFR-Transaktivierung SFTK-abhängig sind. Im Gegensatz dazu ist die EGFR-Tyrosinphosphorylierung SFTK-unabhängig. Diese Daten zeigen, dass die CCK-induzierte Signalvermittlung des EGFR die gemeinsame Aktivierung von SFTK und EGFR benötigt. Neben der EGFR-Transaktivierung konnte im Rahmen der CCK-induzierten MAPK-Aktivierung ein weiterer Signaltransduktionsweg charakterisiert werden, welcher die Aktivierung der Proteinkinase C (PKC) beinhaltet. Es konnte gezeigt werden, dass CCK in AR42J-Zellen eine Aktivierung der PKC-Isoformen alpha, delta und eta induziert. Eine Hemmung aller drei PKC-Isoformen führte zur Hemmung des MAPK-Signals, während die isolierte Hem-mung von PKC alpha und delta keine Effekte verursachte. Diese Resultate deuten darauf hin, dass PKCeta an der CCK-induzierten MAPK-Aktivierung beteiligt ist. Eine Beteiligung der PKC an der EGFR-Transaktivierung konnte nicht nachgewiesen werden. Demnach scheint der PKC-abhängige MAPK-Aktivierungsmechanismus parallel zum EGFR zu verlaufen und erst distal des EGFR mit dem EGFR/SFTK-abhängigen Signaltransduktionsweg zu konvergieren.Activation of mitogen-activated protein kinase (MAPK) plays a key role in mediating proliferative effects of both receptor tyrosine kinases (RTKs) such as the epidermal growth factor receptor (EGFR) and G-protein coupled receptors (GPCR). Compared to the EGFR pathway the mechanism by which GPCR induce MAPK activation is still poorly understood and depends on receptor and cell type. The aim of the present study was to characterize the CCK-induced signal transduction pathways leading to MAPK activation in the pancreatic acinar carcinoma cell line AR42J using immunoblot analyses. The results show an involvement of the EGFR in CCK-induced MAPK activation. CCK induces transactivation of the EGFR which includes tyrosine phosphorylation of both EGFR and Shc and complex formation of the docking proteins Shc and Grb2 with the EGFR. These effects depend on the intrinsic tyrosine kinase activity of the EGFR. Further investigations also demonstrate an involvement of Src family tyrosine kinases (SFTK) in CCK-induced MAPK activation. The data show that CCK-induced EGFR tyrosine phosphorylation is SFTK-independent, whereas CCK-induced complex formation of Shc-Grb2 with the EGFR and Shc tyrosine phosphorylation requires SFTK activity. These results indicate that a concerted action of both EGFR and SFTK is required for CCK-induced EGFR signalling. Beside of EGFR transactivation, activation of a protein kinase C (PKC) appears to be involved in CCK-induced MAPK activation. CCK was shown to activate PKCalpha as well as PKCdelta and -eta. Inhibition of all three PKC isoenzymes reduced CCK-induced MAPK activation while specific inhibition of PKCalpha and PKCdelta had no effect. These findings suggest an involvement of PKCeta in CCK-induced MAPK activation. On the other hand CCK-induced EGFR transactivation was PKC-independent. Taken together, these results indicate that in addition to the EGFR/SFTK pathway CCK-induced MAPK activation also requires activation of another pathway involving PKC which mediates MAPK activation in an EGFR/SFTK-independent manner and converges with the EGFR-dependent pathway downstream of the EGFR

Invasive Mold Infection of the Central Nervous System in Immunocompromised Children

Background: Due to the difficulties in the definite diagnosis, data on brain imaging in pediatric patients with central nervous system (CNS)-invasive mold infection (IMD) are scarce. Our aim was to describe brain imaging abnormalities seen in immunocompromised children with CNS-IMD, and to analyze retrospectively whether specific imaging findings and sequences have a prognostic value. Methods: In a retrospective study of 19 pediatric patients with proven or probable CNS-IMD, magnetic resonance imaging (MRI)-findings were described and analyzed. The results were correlated with outcome, namely death, severe sequelae, or no neurological sequelae. Results: 11 children and 8 adolescents (11/8 with proven/probable CNS-IMD) were included. Seven of the patients died and 12/19 children survived (63%): seven without major neurological sequelae and five with major neurological sequelae. Multifocal ring enhancement and diffusion restriction were the most common brain MRI changes. Diffusion restriction was mostly seen at the core of the lesion. No patient with disease limited to one lobe died. Perivascular microbleeding seen on susceptibility weighted imaging (SWI) and/or gradient-echo/T2* images, as well as infarction, were associated with poor prognosis. Conclusions: The presence of infarction was related to poor outcome. As early microbleeding seems to be associated with poor prognosis, we suggest including SWI in routine diagnostic evaluation of immunocompromised children with suspected CNS-IMD

Abdominal Actinomycosis Associated with a Sigmoid Colon Perforation in a Patient with a Ventriculoperitoneal Shunt

Abdominal actinomycosis causing hydronephrosis in a patient with a ventriculoperitoneal shunt is very rare. A 27-year-old female patient was admitted complaining of lower abdominal pain. She had undergone ventriculoperitoneal shunt surgery 10 years ago. Abdominal Ultrasonography and a CT scan demonstrated an inflammatory mass in the lower left quadrant of the abdomen causing obstructive hydroureter and hydronephrosis. Laparotomy revealed a diffusely infiltrating mass involving the small bowel, mesentery, and sigmoid colon, and a 1 cm perforation in the sigmoid colon. Actinomycosis was diagnosed upon histological examination. After treatment with antibiotics and surgery, the patient's condition improved

Identification of major rice allergen and their clinical significance in children

PurposeRecently, an increase in the number of patients sensitized to rice allergen with or without clinical symptoms has been reported. This study was designed to determine the major allergens in rice and their clinical significance.MethodsTwenty-four children (15 boys and 9 girls; mean age, 16.3 months) with allergic disease, who were sensitized to rice antigen (by UniCAP) in the Pediatric Allergy Respiratory Center at Soonchunhyang University Hospital, were enrolled in this study. The allergenicity of various types of rice (raw, cooked, and heat-treated, simulated gastric fluid [SGF], and simulated intestinal fluid [SIF]) was investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and immunoglobulin E (IgE) immunoblots. The patients' medical records, including laboratory data and allergy symptoms after ingestion of rice were reviewed.ResultsPatients were sensitized to an average of 13.5 food antigens and their mean total IgE was 6,888.7 kU/L. In SDS-PAGE, more than 16 protein bands were observed in the raw rice, whereas only 14-16 kDa and 31-35 kDa protein bands were observed in cooked rice. The common SDS-PAGE protein bands observed in SGF-, SIF-, and heat-treated rice were 9, 14, and 31 kDa. In a heated-rice IgE immunoblot, protein bands of 9, 14, and 31-33 kDa were found in 27.8%, 38.9%, and 38.9% of all sera, respectively, and in 50%, 50%, and 75%, of ser a from the 4 symptomatic patients, respectively.ConclusionThe 9-, 14-, and 31-kDa protein bands appeared to be the major allergens responsible for rice allergy symptoms

Ginkgo biloba extract (GbE) enhances the anti-atherogenic effect of cilostazol by inhibiting ROS generation

In this study, the synergistic effect of 6-[4-(1-cyclohexyl-1H-tetrazol-5-yl) butoxy]-3,4-dihydro-2(1H)-quinolinone (cilostazol) and Ginkgo biloba extract (GbE) was examined in apolipoprotein E (ApoE) null mice. Co-treatment with GbE and cilostazol synergistically decreased reactive oxygen species (ROS) production in ApoE null mice fed a high-fat diet. Co-treatment resulted in a significantly decreased atherosclerotic lesion area compared to untreated ApoE mice. The inflammatory cytokines and adhesion molecules such as monocyte chemoattractant-1 (MCP-1), soluble vascular cell adhesion molecule-1 (sVCAM-1), and VCAM-1 which can initiate atherosclerosis were significantly reduced by the co-treatment of cilostazol with GbE. Further, the infiltration of macrophages into the intima was decreased by co-treatment. These results suggest that co-treatment of GbE with cilostazol has a more potent anti-atherosclerotic effect than treatment with cilostazol alone in hyperlipidemic ApoE null mice and could be a valuable therapeutic strategy for the treatment of atherosclerosis

Clinical Effects of Activated Charcoal Unavailability on Treatment Outcomes for Oral Drug Poisoned Patients

Background. Activated charcoal is the most frequently and widely used oral decontaminating agent in emergency departments (EDs). However, there is some debate about its clinical benefits and risks. In Korea, activated charcoal with sorbitol was unavailable as of the mid-2015, and our hospital had been unable to use it from September 2015. This study examined the differences of clinical features and outcomes of patients during the periods charcoal was and was not available. Methods. We retrospectively reviewed the electronic medical records of patients who had visited an urban tertiary academic ED for oral drug poisoning between January 2013 and January 2017. Results. For the charcoal-available period, 413 patients were identified and for the charcoal-unavailable period, 221. Activated charcoal was used in the treatment of 141 patients (34%) during the available period. The mortality rates during the available and unavailable periods were 1.9 and 0.9%, respectively (p = 0.507). There was also no interperiod difference in the development of aspiration pneumonia (9.9 versus 9.5%, p = 0.864), the endotracheal intubation rate (8.4 versus 7.2%, p = 0.586), and vasopressor use (5.3 versus 5.0%, p = 0.85). Intensive care unit (ICU) admission was higher in the unavailable period (5.8 versus 13.6%, p = 0.001). ICU days were lower in the unavailable period (10 [4.5-19] versus 4 [3-9], p = 0.01). Hospital admission (43.3 versus 29.9%, p = 0.001) was lower in the unavailable period. Conclusions. In this single center study, there appeared to be no difference in mortality, intubation rates, or vasopressor use between the charcoal-available and charcoal-unavailable periods

Analysis of equivalent circuit models in lithium-ion batteries

This study investigates lithium-ion (Li-ion) battery discharge at a constant current by comparing equivalent circuit simulation data with experimental data. The simulations employ Thévenin equivalent circuit models consisting of a resistance, capacitance, and power source. Voltage and resistance are measured during battery discharge at a constant 2 A direct current (DC). The experimental output results of the resistor-capacitor (RC) circuit are calculated and compared to the simulation results over the time of discharge. Both single and triple RC circuits are utilized in the experiment, with the triple RC circuit model demonstrating less error than the single RC circuit when compared to the simulated data. This study suggests that the output voltage of a Li-ion battery generally obeys a simulated Thévenin equivalent circuit model composed of the multiple RC elements under constant current discharge

Comparative risk of infections between JAK inhibitors versus TNF inhibitors among patients with rheumatoid arthritis: a cohort study

Abstract Background To compare infectious risk between JAK inhibitors (JAKis) versus TNF inhibitors (TNFis) among rheumatoid arthritis (RA) patients in Korea. Methods Using 2009–2019 Korea National Health Insurance Service database, we conducted a cohort study on RA patients initiating a JAKi or TNFi. The primary outcomes were herpes zoster (HZ), serious bacterial (SBI), and opportunistic infections (OI). Propensity-score fine-stratification (PSS) and weighting were applied to adjust for > 70 baseline covariates. Hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox proportional hazard models comparing JAKi versus TNFi users. Results We included 2963 JAKi initiators PSS-weighted on 5169 TNFi initiators. During a follow-up of 1.16 years, the most frequent type of infections was HZ with incidence rate (IR) per 100 person-years of 11.54 and 4.88 in JAKi and TNFi users, respectively. The IR of SBI was 1.39 and 1.32, respectively. The OI was rare with a majority being tuberculosis and showed an IR of 0.11 and 0.49 in JAKi and TNFi users, respectively. The PSS-weighted HR (95% CI) for individual types of infections was 2.37 (2.00–2.80) for HZ, 1.04 (0.71–1.52) for SBI, and 0.25 (0.09–0.73) for OI. Conclusions This population-based cohort study on RA patients treated with JAKi or TNFi in Korea showed an exceptionally high IR of HZ in both treatment groups compared to that from Western countries, with an approximately doubled risk associated with JAKi versus TNFi use. The risk of SBI was comparable, but the risk of OI, particularly tuberculosis, was less among JAKi than TNFi initiators

Stability-Enhanced Liquid Crystal Mode for Flexible Display Applications

Abstract We demonstrated stability-enhance