Experimental Verification for Numerical Simulation of Thalamic Stimulation-Evoked Calcium-Sensitive Fluorescence and Electrophysiology with Self-Assembled Multifunctional Optrode.

Owing to its capacity to eliminate a long-standing methodological limitation, fiber photometry can assist research gaining novel insight into neural systems. Fiber photometry can reveal artifact-free neural activity under deep brain stimulation (DBS). Although evoking neural potential with DBS is an effective method for mediating neural activity and neural function, the relationship between DBS-evoked neural Ca2+ change and DBS-evoked neural electrophysiology remains unknown. Therefore, in this study, a self-assembled optrode was demonstrated as a DBS stimulator and an optical biosensor capable of concurrently recording Ca2+ fluorescence and electrophysiological signals. Before the in vivo experiment, the volume of tissue activated (VTA) was estimated, and the simulated Ca2+ signals were presented using Monte Carlo (MC) simulation to approach the realistic in vivo environment. When VTA and the simulated Ca2+ signals were combined, the distribution of simulated Ca2+ fluorescence signals matched the VTA region. In addition, the in vivo experiment revealed a correlation between the local field potential (LFP) and the Ca2+ fluorescence signal in the evoked region, revealing the relationship between electrophysiology and the performance of neural Ca2+ concentration behavior. Concurrent with the VTA volume, simulated Ca2+ intensity, and the in vivo experiment, these data suggested that the behavior of neural electrophysiology was consistent with the phenomenon of Ca2+ influx to neurons.

Validating the diagnosis of acute ischemic stroke in a National Health Insurance claims database.

BACKGROUND/PURPOSE: The National Health Insurance Research Database, which uses claims data from hospitals contracted with the National Health Insurance (NHI) program in Taiwan, has been widely used for stroke research. The diagnostic accuracy of the NHI claims data with regard to acute ischemic stroke (AIS) has rarely been validated. The aim of this study was to validate the diagnosis of AIS in NHI claims data using the Taiwan Stroke Registry (TSR) as a reference. METHODS: We retrieved patients' data with a discharge diagnosis of AIS [five-digit International Classification of Diseases Code, 9(th) version (ICD-9 code): 433xx or 434xx] in a single medical center from August 2006 to December 2008. We then linked these patients to the TSR to validate their AIS diagnosis in the claims data. The positive predictive value (PPV) and sensitivity were determined. RESULTS: We reviewed the claims data of 1736 consecutive AIS patients, of whom 1299 (74.8%) were linked successfully to the stroke registry database. After reviewing the medical records and imaging results of other patients not linked to the registry database (n = 437), 235 patients were found to have had an AIS. The PPV was 88.4% [95% confidence interval (CI): 86.8-89.8%] and sensitivity was 97.3% (95% CI: 96.4-98.1%). Forty-four (21.8%) of the false-positive cases (n = 202) were coded as 433x0 or 434x0. CONCLUSION: The PPV of a diagnosis of AIS in the NHI claims data was high. Using five-digit ICD-9 codes to identify AIS cases will markedly decrease the false-positive rate compared with using the commonly used three-digit method.

Studies on pharmacokinetic mechanism of phenytoin resistance in refractory epilepsy.

P-glycoprotein (P-gp) is a drug efflux pump in many organs, including the intestine and liver. Two single nucleotide polymorphisms (SNPs) of P-gp gene, 2677G>T and 3435C>T, were reported to influence function and expression of P-gp and have the controversial effects on drug disposition. Phenytoin is one substrate of P-gp. Persistent low phenytoin levels in plasma and P-gp overexpression in brain in several refractory epilepsy patients were reported. P-gp polymorphisms may also affect phenytoin efficacy by altering its bioavailability (F). Because two P-gp SNPs, 2677G>T and 3435C>T, may affect P-gp expression in tissue, we examined phenytoin disposition in patients of different P-gp haplotypes, G/G2677C/C3435 and T/T2677T/T3435. We found that the mean absolute F of phenytoin in T/T2677T/T3435 subjects (91%) is slightly higher than in G/G2677C/C3435 subjects (82%). There was no difference in the maximum concentration (Cmax ) and the area under the serum concentration-time curve of phenytoin administered orally between two genotypic groups. However, the time of maximum concentration was higher in T/T2677T/T3435 subjects (10 h) than in G/G2677C/C3435 subjects (6 h). The study ruled out the possibility that genetic polymorphisms of P-gp may affect phenytoin efficacy through the decreased absorption or the increased elimination. P-gp SNPs could affect phenytoin efficacy in refractory epilepsy patients probably because of central nervous system.

The dilemma of treating vertebrobasilar dolichoectasia.

Vertebrobasilar dolichoectasia (VBD) is a common phenomenon among people over 50 years old, and the related clinical expressions are varied. One of our VBD patients presented with brainstem infarction initially, received low molecular weight heparin treatment, and developed rupture of the dolichoectasia segment. Another patient with a similar-sized VBD experienced recurrent brainstem infarction three times over 2 years, despite higher bleeding tendency and long-term antiplatelet treatment. The third patient with a smallersized VBD, had left hemiplegia and received intravenous recombinant tissue plasminogen activator within 3 h, totally recovered with no lesions detected on brain Magnetic Resonance Imaging (MRI). The pathophysiology of VBD is unique, its prevalence and risks of ischemic stroke and intracranial hemorrhage both increase as the degree of arterial dolichoectasia extends, making the strategy of management quite a challenge. The best management of VBD is controlling arterial hypertension and following up with image studies regularly to detect the early extension of VBD degree.

Validation of the National Health Insurance Research Database with ischemic stroke cases in Taiwan.

OBJECTIVE: The National Health Insurance Research Database (NHIRD) is commonly used for pharmacoepidemiological research in Taiwan. This study evaluated the validity of the database for patients with a principal diagnosis of ischemic stroke. STUDY DESIGN AND METHODS: This cross-sectional study compares records in the NHIRD with those in one medical center. Patients hospitalized for ischemic stroke in 1999 were identified from both databases. The discharge notes, laboratory data, and medication orders during admission and the first discharge visit were reviewed to validate ischemic stroke diagnoses and aspirin prescribing in the NHIRD. Agreement between the two databases in comorbidities of ischemic stroke diagnosis was evaluated using ICD-9 codes. RESULTS: Three hundred and seventy two cases were identified from the NHIRD; among them, 364 cases (97.85%) were confirmed as ischemic stroke by radiology examination and clinical presentation. Among these confirmed cases, 344 (94.51%) were assigned 'ischemic stroke' as the principal diagnosis in the NHIRD. The overall agreement of comorbid diagnoses between the databases was 48.39%. The PPV for selected conditions also varied widely, from 0.50 for fracture to 1.00 for colon cancer. The accuracy of recorded aspirin prescriptions was higher in first post-discharge visits (PPV = 0.94) than during hospitalization (PPV = 0.88). CONCLUSION: The accuracy of the NHIRD in recording ischemic stroke diagnoses and aspirin prescriptions was high, and the NHIRD appears to be a valid resource for population research in ischemic stroke.

Reversible postvaccination paraneoplastic encephalomyelitis in a patient with lung adenocarcinoma.

Encephalomyelitis occurs in paraneoplastic syndrome and acute disseminated encephalomyelitis through different autoimmune mechanisms. No postvaccinal encephalomyelitis other than acute disseminated encephalomyelitis has been reported in patients with malignancy. A 68-year-old woman was admitted because of a headache followed by a gait disturbance and psychomotor retardation 2 days after she had received an influenza vaccination followed by abulia, limb rigidity and hyperreflexia of both legs, and meningeal irritation. Cerebrospinal fluid studies showed increased intracranial pressure, elevated immunoglobulins G and A, and pleocytosis. Contrasted brain magnetic resonance imaging revealed ventriculomegaly and multiple symmetric leptomeningeal enhancement, without demyelinating changes or cortical ribbon signs. Somatosensory evoked potentials and nerve conduction velocity studies suggested myelitis. Encephalomyelitis was diagnosed on the basis of clinical and laboratory examinations. The etiological survey identified a lung adenocarcinoma. Both the encephalomyelitis and the lung adenocarcinoma simultaneously progressed after the vaccination and then, after targeted therapy for lung cancer, simultaneously subsided. In conclusion, postinfluenza-vaccination paraneoplastic encephalomyelitis may occur in patients with lung adenocarcinoma.

Get With the Guidelines-Stroke performance indicators: surveillance of stroke care in the Taiwan Stroke Registry: Get With the Guidelines-Stroke in Taiwan.

BACKGROUND: Stroke is a leading cause of death around the world. Improving the quality of stroke care is a global priority, despite the diverse healthcare economies across nations. The American Heart Association/American Stroke Association Get With the Guidelines-Stroke program (GWTG-Stroke) has improved the quality of stroke care in 790 US academic and community hospitals, with broad implications for the rest of the country. The generalizability of GWTG-Stroke across national and economic boundaries remains to be tested. The Taiwan Stroke Registry, with 30 599 stroke admissions between 2006 and 2008, was used to assess the applicability of GWTG-Stroke in Taiwan, which spends ≈ 1/10 of what the United States does in medical costs per new or recurrent stroke. METHODS AND RESULTS: Taiwan Stroke Registry, sponsored by the Taiwan Department of Health, engages 39 academic and community hospitals and covers the entire country with 4 steps of quality control to ensure the reliability of entered data. Five GWTG-Stroke performance measures and 1 safety indicator are applicable to assess Taiwan Stroke Registry quality of stroke care. Demographic and outcome figures are comparable between GWTG-Stroke and Taiwan Stroke Registry. Two indicators (early and discharge antithrombotics) are close to GWTG-Stroke standards, while 3 other indicators (intravenous tissue plasminogen activator, anticoagulation for atrial fibrillation, lipid-lowering medication) and 1 safety indicator fall behind. Preliminary analysis shows that compliance with selected GWTG-Stroke guidelines is associated with better outcomes. CONCLUSIONS: Results suggest that GWTG-Stroke performance measures, with modification for ethnic factors, can become global standards across national and economic boundaries for assessing and improving quality of stroke care and outcomes. GWTG-Stroke can be incorporated into ongoing stroke registries across nations.

Inhibition of CYP3A4 expression by ketoconazole is mediated by the disruption of pregnane X receptor, steroid receptor coactivator-1, and hepatocyte nuclear factor 4alpha interaction.

BACKGROUND: Earlier studies have shown that ketoconazole inhibits CYP3A4 expression through pregnane X receptor (PXR)-mediated transcription and coactivator interaction. The involvement of other nuclear receptors remains to be elucidated. It was recently reported that hepatocyte nuclear receptor 4alpha (HNF4alpha), a master regulator of several nuclear receptors, associates with PXR thus regulates the expression of CYP3A4 under rifampin treatment. We therefore focused on the role of PXR-HNF4alpha interaction in the transcriptional regulation of CYP3A4 under rifampin-mediated ketoconazole inhibition. METHODS AND RESULTS: Several approaches were used to characterize this role and to investigate the relation between the regulatory function of the PXR-HNF4alpha complex and CYP3A4 expression, including a mammalian two-hybrid system, DNA affinity precipitation assay, co-immunoprecipitation, and HNF4alpha silencing by RNA interference. Here, we report that HNF4alpha plays a critical role in CYP3A4 promoter activation, and the interaction between PXR and HNF4alpha, which is closely related to the expression of CYP3A4, might be involved in ketoconazole-mediated inhibition of CYP3A4 gene expression. These observations indicate that the inhibition of the interaction of PXR with HNF4alpha is likely an important mechanism of drug-drug interaction.

The effects of ergoloid mesylates and ginkgo biloba on the pharmacokinetics of ticlopidine.

Ticlopidine is sometimes coadministered with ergoloid mesylates or ginkgo biloba in clinical situations. Our objective was to examine the effect of ergoloid mesylates and ginkgo biloba on ticlopidine pharmacokinetics. Ticlopidine, ergoloid mesylates, and ginkgo biloba significantly inhibited the organic anion transporting polypeptide (OATP-B)-mediated uptake of [(3)H]-estrone-3-sulfate in a concentration-dependent manner. When ergoloid mesylates was coadministered with ticlopidine, the ticlopidine area under the plasma drug concentration-time profile (AUC) from 0 to 12 hours was decreased 30% and the peak plasma drug concentration (C(max)) was decreased 29%, compared with ticlopidine administration alone. There were no significant changes in the pharmacokinetic parameters of ticlopidine when it was coadministered with ginkgo biloba. In summary, ergoloid mesylates is a more potent inhibitor of OATP-B than is ginkgo biloba, and it can reduce the oral bioavailability of drugs transported by OATP-B. Ergoloid mesylates markedly decreased the AUC and C(max) of ticlopidine, probably by inhibiting the OATP-B-mediated uptake of ticlopidine during the intestinal absorption phase. The results support a new model of intestinal drug-drug interaction.

Organic anion transporting polypeptide-C mediates arsenic uptake in HEK-293 cells.

Arsenic is an established human carcinogen. The role of aquaglyroporins (AQPs) in arsenic disposition was recently identified. In order to examine whether organic anion transporting polypeptide-C (OATP-C) also plays a role in arsenic transport, OATP-C cDNA was transfected into cells of a human embryonic kidney cell line (HEK-293). Transfection increased uptake of the model OATP-C substrate, estradiol-17beta-D-glucuronide, by 10-fold. In addition, we measured uptake and cytotoxicity of arsenate, arsenite, monomethylarsonate(MMA(V)), and dimethylarsinate (DMA(V)). Transfection of OATP-C increased uptake and cytotoxicity of arsenate and arsenite, but not of MMA(V) or DMA(V). Rifampin and taurocholic acid (a substrate of OATP-C) reversed the increased toxicity of arsenate and arsenite seen in OATP-C-transfected cells. The increase in uptake of inorganic arsenic was not as great as that of estradiol-17beta-D-glucuronide. Our results suggest that OATP-C can transport inorganic arsenic in a (GSH)-dependent manner. However, this may not be the major pathway for arsenic transport.

Screening CYP3A single nucleotide polymorphisms in a Han Chinese population with a genotyping chip.

Human cytochrome P450 (CYP)3A is a major P450 enzyme found in the liver and gastrointestinal tract. It plays an important role in the metabolism of a wide variety of drugs, some endogenous steroids and harmful environmental contaminants. It has been shown that CYP3A alleles encoding enzymes with little or no activity are largely created by single nucleotide polymorphisms (SNPs) in the sequences of these genes. The most prevalent of these SNPs are often of low allelic frequency, and many are specific to certain ethnic groups. Therefore, an accurate determination of their frequency in any given ethnic population requires investigations involving large sample sizes. A genotyping chip with enzyme-colorimetric detection was developed and used for simultaneous analysis of 22 known CYP3A SNPs in 451 Han Chinese subjects. Following multiplex polymerase chain reaction and allele-specific primer extension labeling, an enzymatic colorimetry detection system was employed to visualize genotype patterns on a nylon membrane. With this robust system, accurate discrimination ratios were obtained, and approximately 9,922 genotypes were determined. We found that the major CYP3A SNPs in the Chinese subjects were CYP3A4*4 (allele frequency 2.4%), CYP3A4*5 (0.7%), CYP3A4*18A (2.7%) and CYP3A5*3C (70.2%). Most of the major CYP3A4 SNPs found in other ethnicities were not found in this study. Using these SNPs, 11 haplotypes were identified. Comparison between present and previous studies shows that CYP3A4*4 and CYP3A4*5 alleles were Chinese-specific. The genotyping chip developed in this study is an efficient, economic and accurate system for screening multiple SNPs in a large population. Application of such technology is expected to be less labor intensive and easier to adapt to specific searches when compared with other methodologies.

Platelet glycoprotein Ia C807T, Ib C3550T, and IIIa Pl(A1/A2) polymorphisms and ischemic stroke in young Taiwanese.

Platelet plays a pivotal role in the pathogenesis of thrombotic cardiovascular diseases. Recently, the polymorphism of platelet glycoprotein (GP) genes has been reported to be associated with an increased risk for ischemic stroke. The purpose of this study is to evaluate the association between platelet GP genetic variants and ischemic stroke in young Taiwanese. We conducted a case-control study in 157 young ischemic stroke patients recruited between September 2001 and March 2003 and 157 age- and sex-matched controls. The genotypes of platelet GP Ia C807T, GP Ib C3550T, and GP IIIa Pl(A1/A2) polymorphisms were analyzed by polymerase chain reaction-restriction fragment length polymorphism. Student's t-test, chi-square test, and logistic regression modeling were used for data analyses. The GP Ia C807T CC, CT and TT genotype frequencies were similar between patients (50.3%, 43.9%, 5.7%) and controls (53.5%, 38.9%, 7.6%; p=0.58). There were no significant differences in GP Ib C3550T CC and CT genotype distributions between patients (91.1%, 8.9%) and controls (91.7%, 8.3%; p=0.84). Of all subjects, none carries GP IIIa Pl(A2) mutation. In conclusion, platelet GP Ia C807T and GP Ib C3550T polymorphisms in our population are less common compared with Caucasians, and GP IIIa Pl(A1/A2) genetic mutation is not found, and all of them are not associated with ischemic stroke in young Taiwanese.

4G/5G promoter polymorphism of plasminogen activator inhibitor-1, lipid profiles, and ischemic stroke.

The 4G allele of common 4G/5G polymorphism in the promoter of the plasminogen activator inhibitor-1 (PAI-1) gene is associated with increased PAI-1 transcription and has been proposed as a candidate genetic risk factor for thrombotic diseases. We investigated the relationship between this polymorphism and lipid profiles and stroke risk. One hundred patients with ischemic stroke and 150 age- and sex-matched control subjects were enrolled. PAI-1 genotype was determined with the use of polymerase chain reaction and restriction-length analysis. Genotype distribution in the stroke group was 40% 4G/4G, 46% 4G/5G, and 14% 5G/5G; in the control group it was 38.7% 4G/4G, 45.3% 4G/5G, and 16% 5G/5G. The allele and genotype frequencies of 4G/5G polymorphism were not different between the stroke and control groups. Control subjects who were homozygous for the 4G allele had significantly lower high-density lipoprotein (HDL) cholesterol levels than did those carrying the 5G allele (51.2 +/- 11.8 vs 58.4 +/- 15.8 mg/dL; P =.002). In the control group, regression analysis revealed a significant contribution of 4G/4G genotype to increased triglyceride (P =.042) and to decreased HDL cholesterol (P <.001) levels. Our findings suggest that PAI-1 4G/5G promoter polymorphism alone is not associated with ischemic stroke. However, this polymorphism influences lipid levels, and the underlying mechanism must be determined.

Dose-response relationships of propranolol in Chinese subjects with different CYP2D6 genotypes.

BACKGROUND: For clinical treatment, a smaller dosage of propranolol is often used among Chinese people. Propranolol is metabolized by polymorphic CYP2D6. We postulate that the lower propranolol dosage in Chinese is due to a slower CYP2D6 metabolism. A majority of the Chinese population has the nucleotide T188 in the CYP2D6 gene (CYP2D6*10) instead of C188 (CYP2D6*1), which most white subjects have. Chinese subjects of different CYP2D6*1/CYP2D6*10 genotypes have been shown to have different propranolol pharmacokinetic characteristics. In this study, we compared the beta-blockade effects of propranolol in Chinese subjects of the two different CYP2D6 genotypes. METHODS: Based on the nucleotide 188 genotypes, two groups of 10 healthy subjects each were selected. Each subject was given a 10-, 20-, or 40-mg rac-propranolol tablet three times a day for 3 days in 3 different phases. Heart rate and blood pressure were measured in both supine and upright positions. The heart rate was also determined during treadmill exercise test. Plasma concentration of S-propranolol at 2 hrs after the last-dose administration was measured. RESULTS: Despite therebeing higher S-propranolol plasma concentration in CYP2D6*10 subjects than in CYP2D6*1 subjects at 10- and 20-mg dosage, the dose-response relationship was not significantly different in these subjects. CONCLUSIONS: Our results do not support the hypothesis that CYP2D6*1/CYP2D6*10 polymorphism may affect the beta-blockade effect of propranolol in Chinese subjects.

Lamotrigine-related skin rashes in adults.

Skin rash is a common adverse effect of lamotrigine (LTG) in both add-on and monotherapy trials and is also the most common adverse event causing LTG withdrawal. From our series of 254 prospectively registered adult patients treated with LTG at a dosage of 25-100 mg/ day, the incidence of allergic and non-allergic skin reactions was 5.1% (13/254) and 1.9% (5/254), respectively. Meanwhile, the rate of allergic skin rashes causing LTG withdrawal was 3.9% (10/254). Co-medication with valproic acid (9.1%) resulted in a higher risk than co-medication with enzyme-inducing antiepileptic medications (2.8%). Moreover, another risk factor was higher initiation and relatively rapid dosage escalation. Among the 13 patients with allergic skin reaction, skin rash appeared during the initiation phase in 12 patients. All the allergic skin lesions were mild, except one presenting with Stevens-Johnson syndrome (0.4%). The patient was an 85-year-old female treated with LTG monotherapy. Three of 13 patients with allergic skin responses were maintained on LTG with concomitant use of anti-allergic medications, and their rashes gradually disappeared. Another three patients agreed on rechallenge with LTG with a smaller dose of no more than 12.5 mg/day after the disappearance of their skin rashes and there was no recurrence of allergic reaction. In conclusion, the incidence and risk factors of LTG-related skin rashes in the present study of adults with epilepsy were comparable to findings from clinical trials in Western countries.