Identification of a Novel ERK5 (MAPK7) Inhibitor, MHJ-627, and Verification of Its Potent Anticancer Efficacy in Cervical Cancer HeLa Cells.

Extracellular signal-regulated kinase 5 (ERK5), a member of the mitogen-activated protein kinase (MAPK) family, is involved in key cellular processes. However, overexpression and upregulation of ERK5 have been reported in various cancers, and ERK5 is associated with almost every biological characteristic of cancer cells. Accordingly, ERK5 has become a novel target for the development of anticancer drugs as inhibition of ERK5 shows suppressive effects of the deleterious properties of cancer cells. Herein, we report the synthesis and identification of a novel ERK5 inhibitor, MHJ-627, and verify its potent anticancer efficacy in a yeast model and the cervical cancer HeLa cell line. MHJ-627 successfully inhibited the kinase activity of ERK5 (IC50: 0.91 µM) and promoted the mRNA expression of tumor suppressors and anti-metastatic genes. Moreover, we observed significant cancer cell death, accompanied by a reduction in mRNA levels of the cell proliferation marker, proliferating cell nuclear antigen (PCNA), following ERK5 inhibition due to MHJ-627 treatment. We expect this finding to serve as a lead compound for further identification of inhibitors for ERK5-directed novel approaches for oncotherapy with increased specificity.

Synthesis of 1,4-Dialkoxynaphthalene-Based Imidazolium Salts and Their Cytotoxicity in Cancer Cell Lines.

In this study, we designed and synthesized novel 1,4-dialkoxynaphthalene-2-alkyl imidazolium salt (IMS) derivatives containing both 1,4-dialkoxynaphthalene and imidazole, which are well known as pharmacophores. The cytotoxicities of these newly synthesized IMS derivatives were investigated in order to explore the possibility of using them to develop anticancer drugs. It was found that some of the new IMS derivatives showed good cytotoxic activities. In addition, an initial, qualitative structure-activity relationship is presented on the basis of observations of activity changes corresponding to structural changes.

Real-world prescribing trends of valproate in women with epilepsy in Korea.

Avoiding valproate is recommended in women of childbearing age due to possible teratogenicity and infertility. We aimed to examine the recent trend of valproate prescriptions in Korea to review the adequacy of anticonvulsant prescriptions in women with epilepsy (WWE). Oral valproate utilization was assessed using nationwide and unselected data from the Korean National Health Insurance Service from 2009 to 2017. The temporal trends of the proportions of valproate prescriptions were analyzed using the Poisson regression model and expressed as average annual percentage change (AAPC). Among the WWE of childbearing age, valproate was prescribed in 37.0% overall and 29.4% as initial prescription in 2017. The proportion of valproate utilization showed a decreasing trend in overall prescription (AAPC = -1.10%) and initial prescription (AAPC = -2.63%). However, the proportion was static over time in the initial monotherapy group (AAPC = -0. 53%), while it was significantly decreasing in the initial polytherapy group (AAPC = -8.25%). A noticeable proportion of WWE was still being prescribed valproate in Korea. In particular, the use of valproate for initial monotherapy has not decreased over the past nine years. This result calls not only for reinforcement of education regarding anticonvulsant selection but also for monitoring the actual prescription.

Δ8(14)-Ergostenol Glycoside Derivatives Inhibit the Expression of Inflammatory Mediators and Matrix Metalloproteinase.

Arthritis is a chronic inflammatory disease accompanied by pathological reactions such as swelling, redness, fever, and pain in various joint areas. The drugs currently available to treat arthritis are associated with diverse side-effects. Therefore, there is a need for safer and more effective treatments to alleviate the inflammation of arthritis with fewer side-effects. In this study, a new sterol, Δ8(14)-ergostenol, was discovered, and its glycosides were synthesized and found to be more efficient in terms of synthesis or anti-inflammatory activity than either spinasterol or 5,6-dihydroergosterol is. Among these synthetic glycosides, galactosyl ergostenol inhibited the expression of inflammatory mediators in TNF-α-stimulated FLS and TNF-α-induced MMPs and collagen type II A1 degradation in human chondrocytes. These results suggest the new galactosyl ergostenol as a treatment candidate for arthritis.

Development of the clinical assessment scale in autoimmune encephalitis.

OBJECTIVE: There is no scale for rating the severity of autoimmune encephalitis (AE). In this study, we aimed to develop a novel scale for rating severity in patients with diverse AE syndromes and to verify the reliability and validity of the developed scale. METHODS: The key items were generated by a panel of experts and selected according to content validity ratios. The developed scale was initially applied to 50 patients with AE (development cohort) to evaluate its acceptability, reproducibility, internal consistency, and construct validity. Then, the scale was applied to another independent cohort (validation cohort, n = 38). RESULTS: A new scale consisting of 9 items (seizure, memory dysfunction, psychiatric symptoms, consciousness, language problems, dyskinesia/dystonia, gait instability and ataxia, brainstem dysfunction, and weakness) was developed. Each item was assigned a value of up to 3 points. The total score could therefore range from 0 to 27. We named the scale the Clinical Assessment Scale in Autoimmune Encephalitis (CASE). The new scale showed excellent interobserver (intraclass correlation coefficient [ICC] = 0.97) and intraobserver (ICC = 0.96) reliability for total scores, was highly correlated with modified Rankin scale (r = 0.86, p < 0.001), and had acceptable internal consistency (Cronbach α = 0.88). Additionally, in the validation cohort, the scale showed high interobserver reliability (ICC = 0.99) and internal consistency (Cronbach α = 0.92). INTERPRETATION: CASE is a novel clinical scale for AE with a high level of clinimetric properties. It would be suitable for application in clinical practice and might help overcome the limitations of current outcome scales for AE. ANN NEUROL 2019;85:352-358.

The prevalence and clinical significance of sleep disorders in acute ischemic stroke patients-a questionnaire study.

PURPOSE: Sleep disturbances are frequently reported in stroke patients and associated with the outcome of strokes. Using sleep questionnaires, we investigated the prevalence of classified sleep disturbance and the influence of sleep disorders upon a stroke prognosis. METHODS: Patients with acute ischemic strokes or transient ischemic attacks (TIA) were included. We investigated the prevalence of sleep disturbance and the association of outcomes resulting from strokes. The National Institutes of Health Stroke Scale score at day 7 (NIHSS-7) and modified Rankin Scale score at month 3 (mRS-3) stood for short- and long-term outcomes. A series of questionnaires including all Korean versions of the Pittsburgh Sleep Quality Index (PSQI-K), Insomnia Severity Index (ISI-K), Epworth Sleepiness Scale (ESS-K), Berlin Questionnaire, Sleep Obstructive apnea score optimized for Stroke (SOS), Beck Depression Inventory-2, and Hospital Anxiety and Depression Scale were used. RESULTS: A total of 241 (mean age was 64.2 ± 11.9, 146 males; 60.6%) consecutive acute ischemic stroke patients, including 36 TIAs, were enrolled. The NIHSS score at admission, NIHSS-7, and mRS-3 were 3.26 ± 3.64, 1.72 ± 2.29, and 0.21 ± 0.82, respectively. PSQI-K ≥8.5 was reported in 79 subjects (32.8%), ISI-K ≥15.5 in 29 (12.0%), ESS-K ≥11 in 21 (8.7%), and SOS ≥11 in 48 (20.3%). The NIHSS-7 was associated with the SOS (standardized ß = 0.281, p < 0.001) and the mRS-3 with the ISI-K (standardized ß = 0.219, p = 0.001) and the SOS (standardized ß = 0.171, p = 0.011). CONCLUSIONS: Screening for and intervening in the sleep problems of stroke patients could improve their outcome. As sleep disturbances are associated with short-term and/or long-term outcomes of strokes, active screening and intervention for sleep disturbances after strokes are needed.

Perceived stress in patients with migraine: a case-control study.

BACKGROUND: Perceived stress is the most common trigger for migraine. The objective of this study was to examine the clinical significance of perceived stress in migraine patients. METHODS: This is a case-control study. Consecutive migraine patients who visited a tertiary care hospital were enrolled for this study. They completed self-reported questionnaires including Perceived Stress Scale (PSS), 12-item Allodynia Symptom Checklist (ASC-12), Migraine Disability Assessment Scale (MIDAS), Patient Health Questionnaire-9 (PHQ-9), Generalized Anxiety Disorder-7 (GAD-7), Epworth Sleepiness Scale (ESS), Insomnia Severity Index (ISI), and Migraine-Specific Quality of Life Questionnaire (MSQ). Degree of perceived stress in migraine patients was measured and compared to that in healthy controls. Predictors for perceived stress and their impact on quality of life (QOL) of migraine patients were also determined. RESULTS: A total of 227 migraine patients were eligible for this study, including 103 (45.4%) who had chronic migraine (CM). Mean PSS score was significantly (p < 0.05) higher in CM patients than that in controls after adjusting for education, depression, and anxiety. Although several factors were associated with PSS score, major predictors for PSS were GAD-7 score (ß = 0.358, p < 0.001), PHQ-9 score (ß = 0.304, p < 0.001), ISI score (ß = 0.154, p = 0.005), and CM (ß = -0.104, p = 0.027). There was an inverse relationship between PSS scores and three-dimensional scores of MSQ (p < 0.001). CONCLUSIONS: Chronic migraine is a critical factor for perceived stress. Perceived stress affects QOL of migraine patients.

Perceived stress and its predictors in people with epilepsy.

OBJECTIVE: Perceived stress in people with epilepsy (PWE) is one of the major precipitants for seizures. We investigated the degree of perceived stress in PWE and its predictors. We also aimed to reveal the interrelationships among the predictors. METHODS: This was a case-control study. Consecutive patients visiting a tertiary care epilepsy clinic completed self-reported questionnaires including the Perceived Stress Scale (PSS), Revised Stigma Scale (RSS), Korean version of the Neurological Disorders Depression Inventory for Epilepsy (K-NDDI-E), Generalized Anxiety Disorder - 7 (GAD-7), and short forms of the Patient-Reported Outcomes Measurement Information System - Sleep Disturbance (PROMIS-SD) and Patient-Reported Outcomes Measurement Information System - Sleep-Related Impairment (PROMIS-SRI) scales. RESULTS: The mean score of the PSS was significantly lower in patients with well-controlled epilepsy (WCE) and higher in those with uncontrolled epilepsy compared with controls. Although several factors including demographic, socioeconomic, psychosomatic, and epilepsy-related factors were associated with the PSS score, the strongest predictor for the PSS score was the K-NDDI-E score, followed by the PROMIS-SRI score, the GAD-7 score, and seizure control. Psychosomatic factors exerted both a direct effect on the PSS score and an indirect effect on the PSS score through seizure control. CONCLUSION: Rapid detection and appropriate management of psychiatric and sleep-related problems in PWE may lessen stress and aid in preventing further seizures.

Augmentation in restless legs syndrome patients in Korea.

PURPOSE: Augmentation has been known as the major complication of long-term dopaminergic treatment of restless legs syndrome (RLS). However, there have been no reports on the prevalence of augmentation in Korea. Thus, we aimed to assess the rate of augmentation and evaluate related factors in Korean RLS patients. METHODS: Ninety-four idiopathic RLS patients who have been treated over a period of at least 6 months were enrolled. Thirty subjects were treated with a dopamine agonist only, and 64 were treated with a dopamine agonist and alpha two delta ligands. We assessed the clinical characteristics of those RLS subjects and evaluated the rate of augmentation. Augmentation was assessed using the NIH criteria for augmentation by two RLS experts independently. RESULTS: Eleven subjects (11.7%) were classified as having definitive or highly suggestive clinical indication of augmentation. In comparing the augmentation group with the non-augmentation group, there were no significant differences of baseline clinical characteristics. Four (13.3%) of the dopamine agonists monotherapy group and seven (10.9%) of the combination therapy group were categorized as augmentation. There was no significant difference in the augmentation rate between these two groups. CONCLUSIONS: We found an 11.7% augmentation rate in Korean RLS subjects. There was no difference in the rate of RLS augmentation between the dopaminergic monotherapy group and the combined treatment group. It may be related with using a similar dosage of dopaminergic drugs.

Validation of the generalized anxiety disorder-7 in people with epilepsy: a MEPSY study.

The Generalized Anxiety Disorder-7 (GAD-7) is a valuable instrument to screen for anxiety in primary care patients. However, it has not been validated in people with epilepsy (PWE). Therefore, we validated the GAD-7 and examined its differential effect from adverse effects of antiepileptic drugs (AEDs) on the detection of anxiety in Korean PWE. Eligible patients who visited outpatient clinics in 4 tertiary care hospitals and 1 secondary care hospital underwent several instruments including the Mini International Neuropsychiatric Interview-Plus Version 5.0.0 (MINI-Plus 5.0.0), the Korean version of the Neurological Disorders Depression Inventory for Epilepsy (K-NDDI-E), the Korean version of the Liverpool Adverse Event Profile (K-LAEP), and the Quality of Life in Epilepsy-10 (QOLIE-10). Two hundred forty-three patients were enrolled in the study, and 51 (21.0%) patients had GAD by the MINI-Plus 5.0.0. Cronbach's α coefficient for the GAD-7 was 0.924. At a cutoff score of 6, the GAD-7 had a sensitivity of 92.2%, a specificity of 89.1%, a positive predictive value of 69.1%, and a negative predictive value of 97.7%. The GAD-7 score was well correlated with the K-NDDI-E score, the K-LAEP score, and the QOLIE-10 overall and subscale scores. The impact of adverse effects of AEDs on the GAD-7 was less than that on the K-NDDI-E. In conclusion, the GAD-7 is a reliable and valid screening tool for detecting GAD in PWE.

Topiramate increases the risk of valproic acid-induced encephalopathy.

Metabolic encephalopathy is a rare but serious complication of valproic acid (VPA) therapy that usually presents with impaired consciousness or increased seizure frequency. Although it has been suggested that topiramate (TPM) increases the risk of VPA-induced encephalopathy, the additional risk in patients receiving TPM therapy has not been evaluated. We reviewed all adult patients who took VPA between January 2005 and February 2009 at the Seoul National University Hospital and identified patients with VPA-induced encephalopathy based on clinical and electroencephalography (EEG) data. Information on sex, age, serum ammonia level, serum VPA level, liver function test, and EEG was collected from patient registry and medical data. We enrolled 8,372 patients who received VPA therapy and 1,236 patients who received VPA/TPM combination therapy. We identified 11 patients with VPA-induced encephalopathy (0.13%), 7 of whom received a combination therapy of VPA and TPM. The odds ratio of VPA-induced encephalopathy with TPM over that without TPM was 10.16. There were no significant differences in sex distribution, number of antiepileptic agents, ammonia level, VPA serum level, underlying diseases, dosage of VPA, duration of VPA treatment, treatment of encephalopathy, and outcomes between the two groups. Our study showed that the prevalence of VPA-induced encephalopathy is approximately 0.1% among patients treated with VPA and that the risk of this condition, although still low, can increase by approximately 10 times in the presence of TPM therapy. Based on these results, we suggest that TPM should be carefully used in patients receiving VPA treatment.

Premature Mortality and Causes of Death Among People With Epilepsy: A Nationwide Population-Based Incident Cohort Study.

BACKGROUND AND OBJECTIVES: People with epilepsy (PWE) are at risk of premature death with considerable variability according to the study population. We aimed to estimate the risk and causes of death in PWE according to age, disease severity, disease course, comorbidities, and socioeconomic status in Korea. METHODS: We conducted a nationwide population-based retrospective cohort study using the National Health Insurance database linked with the national death register. Newly treated PWE from 2008 to 2016 who were identified by antiseizure medication (ASM) prescriptions and diagnostic codes for epilepsy/seizure were included and observed until 2017. We assessed all-cause and cause-specific crude mortality rates and standardized mortality ratios (SMRs). RESULTS: Among 138,998 PWE, 20,095 deaths were identified, and the mean follow-up period was 4.79 years. The SMR was 2.25 in the overall group of PWE, with a higher value in the younger age group at diagnosis and a shorter time interval after diagnosis. The SMR in the monotherapy group was 1.56, while that in the group with 4 or more ASMs was 4.93. PWE without any comorbidities had an SMR of 1.61. PWE who were rural residents had a higher SMR than those who were urban residents (2.47 vs 2.03, respectively). The causes of death among PWE were cerebrovascular disease (18.9%, SMR 4.50), malignant neoplasms outside the CNS (15.7%, SMR 1.37), malignant neoplasms of the CNS (6.7%, SMR 46.95), pneumonia (6.0%, SMR 2.08), and external causes (7.2%, SMR 2.17), including suicide (2.6%, SMR 2.07). Epilepsy itself and status epilepticus accounted for 1.9% of the overall death. The excess mortality associated with pneumonia and external causes was persistently high, whereas the excess mortality associated with malignancy and cerebrovascular diseases tended to decrease with increasing time since diagnosis. DISCUSSION: This study showed excess mortality in PWE, even in those without comorbidities and those receiving monotherapy. Regional disparities and sustained risks of deaths from external causes over 10 years imply potential points of intervention. In addition to active control of seizures, education about injury prevention, monitoring for suicidal ideation, and efforts to improve accessibility to epilepsy care are all required to reduce mortality.

Sleep and Circadian Rhythm in Relation to COVID-19 and COVID-19 Vaccination-National Sleep Survey of South Korea 2022.

BACKGROUND: Currently, information on sleep and circadian patterns in relation to COVID-19 or vaccination remains limited. We aimed to investigate sleep and circadian patterns according to history of COVID-19 and COVID-19 vaccination side effects. METHODS: We used data from the National Sleep Survey of South Korea 2022, a nationwide cross-sectional population-based survey regarding sleep-wake behaviors and sleep problems among Korean adults. Analysis of covariance (ANCOVA) and logistic regression analyses were performed to explore the different sleep and circadian patterns according to the history of COVID-19 or self-reported side effects of the COVID-19 vaccination. RESULTS: The ANCOVA showed that individuals with a history of COVID-19 presented a later chronotype than individuals without a history of COVID-19. Individuals who had experienced vaccine-related side effects had a shorter sleep duration, poorer sleep efficiency, and worse insomnia severity. Multivariable logistic regression analysis showed a later chronotype related to COVID-19. A short sleep duration, poorer sleep efficiency, and worse insomnia severity were associated with self-reported side effects of the COVID-19 vaccination. CONCLUSIONS: Individuals who recovered from COVID-19 had a later chronotype than those without a history of COVID-19. Individuals who had experienced vaccine-related side effects presented with poorer sleep than those without side effects.

Synthesis and anti-inflammatory effects of Δ7-Cholestenol and Δ8(14)-Cholestenol derivatives.

In this study, O-glycosides of cholesterol derivatives Δ7-cholestenol and Δ8(14)-cholestenol were prepared by Schmidt glycosylation with various glycosyl imidates. In addition, 1,2,3-triazole-linked N-glycosides of Δ8(14)-cholestenol were prepared via the "click" reaction of proparzylic Δ8(14)-cholestenol with glycosyl azides. The anti-inflammatory activities of these molecules were investigated for inhibitory mRNA expression activity of CCL17 and CCL22, which are important biomarkers of atopic dermatitis. Both the O- and N-glycosides Δ7-cholestenol and Δ8(14)-cholestenol were observed to exhibit good anti-inflammatory activity in vitro. In particular, the 1,2,3-triazole-linked N-glycoside of Δ8(14)-cholestenol exhibited anti-inflammatory activity similar to that of O-glycoside in vitro and is expected to be more potent in vivo due to better stability.

Trends in Prescribing of Antiseizure Medications in South Korea: Real-World Evidence for Treated Patients With Epilepsy.

BACKGROUND AND PURPOSE: We investigated the trends in the prescribing of antiseizure medication (ASM) over a 9-year period, and provide real-world data regarding ASM prescriptions of patients with epilepsy in South Korea. METHODS: This study used data in the Korean National Health Information Database for the period from 2009 to 2017. We included 18 oral ASMs, which were classified into older and newer ASMs based on them first becoming available on the market before or after 1991, respectively. The annual trends in ASM prescriptions were plotted over the 9-year study period, and changes in these trends were evaluated as average annual percentage changes (AAPCs) using Poisson regression. Age- and sex-stratified analyses were also conducted. RESULTS: Overall, the proportion of prescriptions involving polytherapy with three or more ASMs increased from 10.08% in 2009 to 10.99% in 2017 (AAPC=0.9%, p<0.001) over the 9-year study period. Among monotherapies, although valproate (VPA) was the most frequently prescribed ASM, the prescription rate of levetiracetam (LEV) steadily increased regardless of age and sex over the study period. The monotherapy prescription trends differed depending on age and sex. In the five most frequently used ASM combination regimens, the prescription rates of VPA/LEV, LEV/oxcarbazepine, and LEV/lamotrigine regimens showed increasing tendencies. In contrast, prescription rates for all combined regimens of older ASMs declined over time in all age groups. CONCLUSIONS: This is the first epidemiological study of the changes in prescription trends for ASM in South Korea based on nationwide data from 2009 to 2017. We found progressive increases in the use of newer ASMs for both monotherapy and duotherapy, and for polytherapy with three or more ASMs over the 9-year study period.

Mortality, Disability, and Prognostic Factors of Status Epilepticus: A Nationwide Population-Based Retrospective Cohort Study.

BACKGROUND AND OBJECTIVES: The outcome of status epilepticus (SE) largely varies depending on clinical characteristics. Risk stratification is necessary for tailoring the aggressiveness of treatment and predicting outcomes of individual patients with SE. In this study, we assessed differences in mortality, neurologic disability, and prognostic factors associated with SE across sociodemographic and clinical characteristics. METHODS: We conducted a nationwide population-based retrospective cohort study using the National Health Insurance Service (NHIS) database linked with the national death and disability registries. SE was identified from admission or emergency department visits using a diagnostic code of G41 from the International Classification of Diseases, 10th Revision. Individuals with new-onset SE that occurred from January 1, 2010, to December 31, 2018, were included. Active epilepsy, refractoriness of SE, potential etiology, and comorbidities were ascertained by diagnostic codes and/or prescription records from the NHIS database as potential prognostic factors. Outcomes included 30-day and 1-year mortality and neurologic disabilities after SE. Prognostic factors for mortality were assessed by the Cox regression hazard model. We performed a subgroup analysis according to age: pediatric SE (age <20 years) and adult SE (age ≥20 years). RESULTS: A total of 33,814 patients with new-onset SE were included (6,818 children/adolescents and 26,996 adults). The 30-day mortality was 8.5% (1.8% in pediatric SE and 10.2% in adult SE), and the 1-year mortality was 25.1% (4.6% in pediatric SE and 30.3% in adult SE). Overall, 10.7% of patients newly acquired neurologic disabilities after SE, with the highest incidence in children aged 5-9 years (21.3%). Intractable epilepsy developed in 0.8% of entire SE. Old age, presence of acute etiology, and refractoriness were poor prognostic factors for mortality in both pediatric and adult SE. Male sex, low economic status, no active epilepsy, and comorbidities were additional factors for a poor prognosis in adults. DISCUSSION: New-onset SE was associated with substantial mortality and disability. Although SE-related mortality was higher in adults, disabilities developed more commonly in children and adolescents. The major determinants of mortality differed between pediatric and adult SE.

Identification of a potent NAFLD drug candidate for controlling T2DM-mediated inflammation and secondary damage in vitro and in vivo.

Accumulation of glucose/sugar results in the formation of reactive di-carbonyl compounds such as MGO and GO that interact with several amino acids and proteins to form toxic advanced glycation end products (AGEs). Induction of AGEs breakdown can control symptoms and severity in T2DM and other related complications like NAFLD where AGEs are the key players. Therefore, an AGE cross-link breaker has been suggested for preventing the onset/progression of NAFLD. In this study, we reported novel synthetic naphthalene-2-acyl thiazolium derivatives (KHAGs). Among synthesized KHAG derivatives, we observed that a novel KHAG-04, a 1,4-dimethoxynaphthalen-2-acyl thiazolium salt which is an analog of alagebrium, dramatically cleaves MGO/GO-AGE cross-links, and it also inhibited inflammation by lowering the level of nitric oxide production and IL-1ß and TNF-α secretion in LPS and/or MGO-AGE-activated macrophage. Moreover, it also reduced FFA and MGO-AGE-induced lipogenesis in Hep-G2 cells. In mice, KHAG-04 significantly reduced the level of glyoxal in the liver, which was induced by DMC. Furthermore, KHAG-04 treatment significantly reduced blood glucose levels, lipid accumulation, and inflammation in the NAFLD/T2DM animal model. Novel KHAG-04-mediated induction of AGEs breakdown could be the possible reason for its anti-inflammatory, antihyperglycemic, and anti-lipidemic effects in cells and NAFLD in the T2DM animal model, respectively. Further research might explore the pharmacological efficacy and usefulness and consider the ability of this compound in the treatment strategy against various models of NAFLD in T2DM where MGO/GO-AGEs play a key role in the pathogenesis.

On-chip drop-to-drop liquid microextraction coupled with real-time concentration monitoring technique.

This paper demonstrates a novel drop-to-drop liquid-liquid micro-extraction (DTD-LLME) device, which is based on an electrowetting on dielectric (EWOD) digital microfluidic chip. Droplets of two immiscible liquids, one of which is an ionic liquid, are formed in nanoliter volumes, driven along electrodes, merged and mixed for extraction, and finally separated upon the completion of the extraction process. All the steps are carried out on a microfluidic chip using combined electrowetting and dielectrophoretic forces, which act on the droplet upon the application of electric potential. Specially, the phase separation of two immiscible nanoliter-scale liquid drops was achieved for the first time on an EWOD digital microfluidic chip. To study the on-chip extraction kinetics, an image-based concentration measurement technique with suitable color parameters was studied and compared with the typical UV absorption based technique. Finally, the effect of applied ac voltage frequency on the extraction kinetics was studied. The observations on DTD-LLME, particularly phase separation, are discussed. The image-based method was found to be applicable for precise concentration measurements with the right choice of the color parameter. Results from experiments on finding the frequency dependence on extraction kinetics demonstrate that the application of higher frequencies can be a factor in accelerating the extraction on the proposed microextraction device.

Axonal conduction block at intermediate nerve segments in pure motor Guillain-Barré syndrome.

The pathophysiology of axonal Guillain-Barré syndrome (GBS) is not simple axonal degeneration, but includes reversible conduction failure. Acute motor axonal neuropathy (AMAN) and acute motor conduction block (CB) neuropathy are the two subtypes of pure motor axonal GBS, but their nosologic boundary is still in debate. We investigated clinical and electrophysiological features of 21 consecutive patients with GBS in Korea. Analysis was focused on the presence of CB at intermediate nerve segments (iCB) in pure motor GBS, and its serial changes during the acute phase of disease. Pure motor GBS was common (81%), and iCB was observed in 12 patients with pure motor GBS. Clinical features of pure motor GBS with iCB were distinct from sensorimotor GBS, but similar to pure motor GBS without iCB, characterized by frequent preceding diarrhea, uncommon cranial nerve palsy, and fast recovery. The iCB was not restricted to common entrapment sites, and the distal segments were also commonly involved in the nerves with iCB. The temporal course of iCB was marked by a rapid and often disproportionate increase of proximal and distal amplitudes without remyelinating slow components. Clinical and electrophysiological features of pure motor GBS in patients with iCB suggest that acute motor CB neuropathy may constitute a spectrum of axonal GBS, sharing a common pathomechanism with AMAN.

Drop-to-drop liquid-liquid extraction of DNA in an electrowetting-on-dielectric digital microfluidics.

Recent advancements in microfluidics and lab-on-a-chip technologies enabled miniaturization and automation of many downstream nucleic acid analysis steps such as PCR. However, DNA extraction/isolation protocol remains a stand-alone sample preparation step. For a quick sample-to-result solution, downstream protocols and sample preparation protocols need to be seamlessly integrated into a single lab-on-a-chip platform. As a step toward such integration, this paper introduces microfluidic DNA isolation using the liquid-liquid extraction (LLE) method in the drop-to-drop (DTD) format. The electrowetting-on-dielectric digital microfluidic platform is capable of handling a two-phase liquid system easily, which enables DTD LLE. In this study, the extraction of plasmid DNA (pDNA) from an aqueous sample to an ionic liquid is demonstrated. Prior to pDNA extraction study, the DTD LLE protocol was developed and optimized using organic dyes as solutes. The selective extraction of pDNA in the presence of proteins as interfering molecules is also demonstrated. This work implies that DTD LLE can substitute for magnetic beads steps in standard DNA isolation protocols.