Phospholipase C beta 1 in the dentate gyrus gates fear memory formation through regulation of neuronal excitability.

Memory processes rely on a molecular signaling system that balances the interplay between positive and negative modulators. Recent research has focused on identifying memory-regulating genes and their mechanisms. Phospholipase C beta 1 (PLCß1), highly expressed in the hippocampus, reportedly serves as a convergence point for signal transduction through G protein-coupled receptors. However, the detailed role of PLCß1 in memory function has not been elucidated. Here, we demonstrate that PLCß1 in the dentate gyrus functions as a memory suppressor. We reveal that mice lacking PLCß1 in the dentate gyrus exhibit a heightened fear response and impaired memory extinction, and this excessive fear response is repressed by upregulation of PLCß1 through its overexpression or activation using a newly developed optogenetic system. Last, our results demonstrate that PLCß1 overexpression partially inhibits exaggerated fear response caused by traumatic experience. Together, PLCß1 is crucial in regulating contextual fear memory formation and potentially enhancing the resilience to trauma-related conditions.

BDNF-TrkB signaling orchestrates the buildup process of local sleep.

Sleep debt accumulates during wakefulness, leading to increased slow wave activity (SWA) during sleep, an encephalographic marker for sleep need. The use-dependent demands of prior wakefulness increase sleep SWA locally. However, the circuitry and molecular identity of this "local sleep" remain unclear. Using pharmacology and optogenetic perturbations together with transcriptomics, we find that cortical brain-derived neurotrophic factor (BDNF) regulates SWA via the activation of tyrosine kinase B (TrkB) receptor and cAMP-response element-binding protein (CREB). We map BDNF/TrkB-induced sleep SWA to layer 5 (L5) pyramidal neurons of the cortex, independent of neuronal firing per se. Using mathematical modeling, we here propose a model of how BDNF's effects on synaptic strength can increase SWA in ways not achieved through increased firing alone. Proteomic analysis further reveals that TrkB activation enriches ubiquitin and proteasome subunits. Together, our study reveals that local SWA control is mediated by BDNF-TrkB-CREB signaling in L5 excitatory cortical neurons.

Liebig's law of the minimum in the TGF-ß/SMAD pathway.

Cells use signaling pathways to sense and respond to their environments. The transforming growth factor-ß (TGF-ß) pathway produces context-specific responses. Here, we combined modeling and experimental analysis to study the dependence of the output of the TGF-ß pathway on the abundance of signaling molecules in the pathway. We showed that the TGF-ß pathway processes the variation of TGF-ß receptor abundance using Liebig's law of the minimum, meaning that the output-modifying factor is the signaling protein that is most limited, to determine signaling responses across cell types and in single cells. We found that the abundance of either the type I (TGFBR1) or type II (TGFBR2) TGF-ß receptor determined the responses of cancer cell lines, such that the receptor with relatively low abundance dictates the response. Furthermore, nuclear SMAD2 signaling correlated with the abundance of TGF-ß receptor in single cells depending on the relative expression levels of TGFBR1 and TGFBR2. A similar control principle could govern the heterogeneity of signaling responses in other signaling pathways.

Therapeutic Drug Monitoring of 6 New-Generation Antiseizure Medications Using a Mass Spectrometry Method: Analysis of 2-Year Experience in a Large Cohort of Korean Epilepsy Patients.

CONTEXT.­: New-generation antiseizure medications (ASMs) are increasingly prescribed, and therapeutic drug monitoring (TDM) has been proposed to improve clinical outcome. However, clinical TDM data on new-generation ASMs are scarce. OBJECTIVE.­: To develop and validate a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for therapeutic drug monitoring (TDM) of 6 new-generation ASMs in serum and analyze the clinical TDM data from a large cohort of Korean patients with epilepsy. DESIGN.­: Stable isotope-labeled internal standards were added to protein precipitations of serum. One microliter of sample was separated on Agilent Poroshell EC-C18 column, and lacosamide, perampanel, gabapentin, pregabalin, vigabatrin, and rufinamide were simultaneously quantified by Agilent 6460 triple-quad mass spectrometer in multiple-reaction monitoring mode. Linearity, sensitivity, precision, accuracy, specificity, carryover, extraction recovery, and matrix effect were evaluated. TDM data of 458 samples from 363 Korean epilepsy patients were analyzed. RESULTS.­: The method was linear with limit of detection less than 0.05 µg/mL in all analytes. Intraassay and interassay imprecisions were less than 5% coefficient of variation. Accuracy was within ±15% bias. Extraction recovery ranged from 85.9% to 98.8%. A total of 88% (403 of 458) were on polypharmacy, with 29% (118 of 403) using concomitant enzyme inducers. Only 38% (175 of 458) of the concentrations were therapeutic, with 53% (244 of 458) being subtherapeutic. Drug concentration and concentration-to-dose ratio were highly variable among individuals in all 6 ASMs. CONCLUSIONS.­: A simple and rapid LC-MS/MS method for TDM of 6 ASMs was developed and successfully applied to clinical practice. This large-scale TDM data could help establish an effective monitoring strategy for these drugs.

Programmable RNA base editing with photoactivatable CRISPR-Cas13.

CRISPR-Cas13 is widely used for programmable RNA interference, imaging, and editing. In this study, we develop a light-inducible Cas13 system called paCas13 by fusing Magnet with fragment pairs. The most effective split site, N351/C350, was identified and found to exhibit a low background and high inducibility. We observed significant light-induced perturbation of endogenous transcripts by paCas13. We further present a light-inducible base-editing system, herein called the padCas13 editor, by fusing ADAR2 to catalytically inactive paCas13 fragments. The padCas13 editor enabled reversible RNA editing under light and was effective in editing A-to-I and C-to-U RNA bases, targeting disease-relevant transcripts, and fine-tuning endogenous transcripts in mammalian cells in vitro. The padCas13 editor was also used to adjust post-translational modifications and demonstrated the ability to activate target transcripts in a mouse model in vivo. We therefore present a light-inducible RNA-modulating technique based on CRISPR-Cas13 that enables target RNAs to be diversely manipulated in vitro and in vivo, including through RNA degradation and base editing. The approach using the paCas13 system can be broadly applicable to manipulating RNA in various disease states and physiological processes, offering potential additional avenues for research and therapeutic development.

Real-time visualization of structural dynamics of synapses in live cells in vivo.

The structural plasticity of synapses is crucial for regulating brain functions. However, currently available methods for studying synapse organization based on split fluorescent proteins (FPs) have been limited in assessing synaptic dynamics in vivo due to the irreversible binding of split FPs. Here, we develop 'SynapShot', a method for visualizing the structural dynamics of intact synapses by combining dimerization-dependent FPs (ddFPs) with engineered synaptic adhesion molecules. SynapShot allows real-time monitoring of reversible and bidirectional changes of synaptic contacts under physiological stimulation. The application of green and red ddFPs in SynapShot enables simultaneous visualization of two distinct populations of synapses. Notably, the red-shifted SynapShot is highly compatible with blue light-based optogenetic techniques, allowing for visualization of synaptic dynamics while precisely controlling specific signaling pathways. Furthermore, we demonstrate that SynapShot enables real-time monitoring of structural changes in synaptic contacts in the mouse brain during both primitive and higher-order behaviors.

Single-sided magnetic resonance-based sensor for point-of-care evaluation of muscle.

Magnetic resonance imaging is a widespread clinical tool for the detection of soft tissue morphology and pathology. However, the clinical deployment of magnetic resonance imaging scanners is ultimately limited by size, cost, and space constraints. Here, we discuss the design and performance of a low-field single-sided magnetic resonance sensor intended for point-of-care evaluation of skeletal muscle in vivo. The 11 kg sensor has a penetration depth of >8 mm, which allows for an accurate analysis of muscle tissue and can avoid signal from more proximal layers, including subcutaneous adipose tissue. Low operational power and shielding requirements are achieved through the design of a permanent magnet array and surface transceiver coil. The sensor can acquire high signal-to-noise measurements in minutes, making it practical as a point-of-care tool for many quantitative diagnostic measurements, including T2 relaxometry. In this work, we present the in vitro and human in vivo performance of the device for muscle tissue evaluation.

High-resolution assessment of multidimensional cellular mechanics using label-free refractive-index traction force microscopy.

A critical requirement for studying cell mechanics is three-dimensional assessment of cellular shapes and forces with high spatiotemporal resolution. Traction force microscopy with fluorescence imaging enables the measurement of cellular forces, but it is limited by photobleaching and a slow acquisition speed. Here, we present refractive-index traction force microscopy (RI-TFM), which simultaneously quantifies the volumetric morphology and traction force of cells using a high-speed illumination scheme with 0.5-Hz temporal resolution. Without labelling, our method enables quantitative analyses of dry-mass distributions and shear (in-plane) and normal (out-of-plane) tractions of single cells on the extracellular matrix. When combined with a constrained total variation-based deconvolution algorithm, it provides 0.55-Pa shear and 1.59-Pa normal traction sensitivity for a 1-kPa hydrogel substrate. We demonstrate its utility by assessing the effects of compromised intracellular stress and capturing the rapid dynamics of cellular junction formation in the spatiotemporal changes in non-planar traction components.

Clinical and radiological findings in community-acquired pneumonia: A comparison between viral and bacterial infection / 동물의과학연구지

Effective treatment for community-acquired pneumonia (CAP) requires administration of appropriate empirical therapy based on etiologic, clinical, and radiological features. However, in Korea, CAP is poorly characterized, and data on viral CAP are particularly sparse. Therefore, improper use of antibiotics is common, and is detrimental the potential for development of bacterial. Thus, we investigated clinical and radiological findings for discrimination of viral CAP from bacterial CAP. Etiologic, clinical, and radiological data from 467 patients with CAP at Chungbuk National University Hospital from October 2010 to September 2011 were analyzed retrospectively. Viruses were identified in 23 cases (11.4%); the influenza virus A was the most common virus detected (N=18, 25.4%), followed by the respiratory syncytial virus A (N=14, 17.9%). Bacteria were identified in 48 cases (23.8%); Streptococcus-pneumonia was the most common (N=24, 25.5%), followed by Staphylococcus aureus (N=20, 21.3%). Depending on hospitalization time, the following significant differences were observed between viral and bacterial CAP: on admission, (1) high fever (> or = 38.5degrees C), (2) purulent sputum, (3) white blood cell count, (4) C-reactive protein levels, (5) and bilateral lung involvement on chest X-ray were higher in bacterial CAP; and at discharge, (1) duration of high fever and (2) radiologic improvement within three days were higher in viral CAP. Regarding seasonal patterns, both viruses and bacteria have been identified with relative frequency in the winter season. This study described the etiological, clinical, and radiological findings of viral and bacterial CAP. Conduct of additional large-scale, prospective investigations will be required in order to improve the appropriate treatment of CAP.

Invasive Aspergillosis Involving the Lungs and Brain after Short Period of Steroid Injection: A Case Report / 결핵및호흡기질환

Invasive pulmonary aspergillosis (IPA) has emerged as a severe infection in patients with immunocompromised hosts. However, recently, several IPA cases, without an apparent predisposition to immunodeficiency, has been reported. A 72-year-old woman was admitted for evaluation of general weakness and poor oral intake. She reported no medical history, except for intraarticular injection of a corticosteroid for joint pain for the duration of two months. A chest radiography revealed multiple cavitary nodules in both lungs. Examination of specimens, obtained by percutaneous needle biopsy, led to a diagnosis of invasive aspergillosis. Brain magnetic resonance imagining revealed numerous peripheral thin enhancing cystic nodules in both cerebral hemispheres. We initiated intravenous administration of amphotercin B. However, the patient died after nine days. Here, we report an invasive aspergillosis case, which involves the lungs and brain after a short period of steroid injection.

Factors Associated or Related to with Pathological Severity of Nonalcoholic Fatty Liver Disease

BACKGROUND: Nonalcoholic fatty liver disease (NAFLD) has been more and more often regarded as a serious disorder, because nonalcoholic steatohepatitis (NASH), a part of NAFLD, may progress to the end stage of liver disease. Though an advanced age, obesity, diabetes mellitus (DM) etc. being not infrequent conditions in Korea, are known to exacerbate the severity of this disease, there are only a few Korean reports on this subject. The purpose of this study is to identify possible factors that might add up to the pathological severity of this disorder in Korean patients. METHODS: Of 60 patients with steatosis found at liver biopsy, 43 NAFLD patients were reviewed retrospectively after exclusion of other liver diseases. RESULTS: The cases of steatosis were mild, moderate, and severe in 9, 10, and 24 patients, respectively. The degree of necroinflammatory activity was mild, moderate, and severe in 33, 9, and 1 patients, respectively. There were no established factors directly related to these classes. As to fibrosis, the cases were classified as none, mild, moderate, severe, and cirrhotic in 9, 11, 16, 7, and 0 patients, respectively. The stage of fibrosis correlated with the age (p< 0.001), BMI (body mass index) (p=0.032), and the platelet count (p=0.009), but the presence of NASH was associated only with BMI (p=0.002) and obesity (p=0.001). CONCLUSION: It seems that there are no factors that are directly related to the degree of steatosis or necroinflammatory activity. BMI seems to be a unique factor directly related to both the severity of fibrosis and the presence of NASH. The age and the platelet count are factors that are directly related to the degree of fibrosis but not to the presence of NASH.

Development of ARDS by Hemothorax as a Complication of Subclavian Catheter Insertion / 대한신장학회잡지

Subclavian catheters were used in the treatment of chronic renal failure patients waiting for the maturation of AV fistula. But, it sometimes causes fatal complications. Of these, massive bleeding into pleural cavity after subclavian vein cannulation is a rather rare but causes very serious complication. Most of patients with hemothorax are successfully treated with conservative treatment(i.e. pleural drainage, maintaining the circulatory volume, treatment of possible coagulopathy) but it sometimes needs surgery. We recently experienced a case of ARDS complicated by hemothorax which was successfully treated with thracooscopic drainage. We reviewed the pathogenesis of ARDS by hemothorax and suggested the guidlines for the treatment of massive hemothorax using video-assisted thoracoscopic surgery.

Retroperitoneal Abscess by Citrobacter and Klebsiella in a Renal Transpant Recipient / 대한이식학회지

Infectious complications are common causes of morbidity in renal transplant recipients. To date, only two cases of retroperitoneal abscess caused by Norcardia asteroides and Mycobacterium fortuitum were reported in renal transplant recipients in the literature. We report a case of retroperitoneal abscess caused by gram negative bacilli-Citrobacter freundi, Klebsiella pneumoniae. The patient was admitted to the hospital due to flank pain. Abdominal CT scan and CT scan-guided aspiration confirmed retroperitoneal abscess. It is likely that the abscess in our patient was related to the anti-rejection treatment which included high-dose steroids, and mycophenolate mofetil. To our knowledge, this is the first report of retroperitoneal absces caused by gram-negative bacilli.