Cytochrome c oxidase deficit is associated with the seizure onset zone in young patients with focal cortical dysplasia Type II.

It has been postulated that mitochondrial dysfunction may be an important factor in epileptogenesis of intractable epilepsy. The current study tests the hypothesis that mitochondrial Complex IV (CIV) or cytochrome c oxidase dysfunction is associated with the seizure onset zone (SOZ) in patients with focal cortical dysplasia (FCD). Subjects were selected based on: age <19y; epilepsy surgery between May, 2010 and October, 2011; pathological diagnosis of isolated focal cortical dysplasia Type I (FCDI) or Type II (FCDII); and sufficient residual cortical tissue to conduct analysis of electron transport chain complex (ETC) activity in SOZ and adjacent cortical regions. In this retrospective study, patients were identified who had sufficient unfixed, frozen brain tissue for biochemical analysis in tissue homogenates. Specimens were subtyped using ILAE classification for FCD, and excluded if diagnosed with FCD Type III or dual pathology. Analysis of ETC activity in resected tissues was conducted independently and without knowledge of the identity, diagnosis, or clinical status of individual subjects. Seventeen patients met the inclusion criteria, including 6 FCDI and 11 FCDII. Comparison of adjacent cortical resections showed decreased CIV activity in the SOZ of the FCDII group (P = 0.003), but no significant CIV difference in adjacent tissues of the FCDI group. Because of the importance of CIV as the terminal and rate-limiting complex in the mitochondrial electron transport chain, these authors conclude that 1) a deficit of CIV is associated with the SOZ of patients with FCDII; 2) CIV deficiency may contribute to the spectrum of FCD neuropathology; and 3) further investigation of CIV in FCD may lead to the discovery of new targets for neuroprotective therapies for patients with intractable epilepsy.

Cerebral glucose hypometabolism is associated with mitochondrial dysfunction in patients with intractable epilepsy and cortical dysplasia.

OBJECTIVES: Metabolic imaging studies, such as positron emission tomography (PET), allow for an assessment of physiologic functioning of the brain, and [(18)F]fluoro-2-deoxyglucose (FDG)-PET is now a commonly used technique in presurgical epilepsy evaluations. Focal interictal decreases in glucose consumption are often but inconsistently concordant with the ictal onset area, and the underlying mechanisms are poorly understood. The current study tests the hypothesis that areas of glucose hypometabolism, determined by FDG-PET, are associated with mitochondrial dysfunction in patients with medically intractable epilepsy associated with isolated focal cortical dysplasia (FCD). METHODS: Measures of electron transport chain (ETC) functioning and mitochondrial abnormalities (ETC complex biochemistry, protein kinase B subtype 1 (Akt1), glial fibrillary acidic protein (GFAP)) were assessed in surgical resection specimens that had hypometabolic abnormalities and those that were normal on FDG-PET. Determination of FDG-PET abnormalities was based on coregistration of statistical parametric mapping (SPM) results with postsurgical images. RESULTS: Twenty-two patients (11 male, 11 female; mean age at the time of surgery 10.5 ± 4.4 years), with pathologically confirmed FCD, were included in this retrospective review. Complex IV function was found to be significantly reduced in areas of hypometabolism (p = 0.014), whereas there was a trend toward a significant reduction in complex II and III function in areas of hypometabolism (p = 0.08, p = 0.059, respectively). These decreases were independent of cortical dysplasia severity (p = 0.321) and other clinical epilepsy measures. SIGNIFICANCE: This study suggests an association between glucose hypometabolism and reduced mitochondrial complex IV functioning, which is independent of the degree of cortical dysplasia. This supports the role of cellular energy failure as a potential mechanism for intractable epilepsy.

High-fructose, medium chain trans fat diet induces liver fibrosis and elevates plasma coenzyme Q9 in a novel murine model of obesity and nonalcoholic steatohepatitis.

UNLABELLED: Diets high in saturated fat and fructose have been implicated in the development of obesity and nonalcoholic steatohepatitis (NASH) in humans. We hypothesized that mice exposed to a similar diet would develop NASH with fibrosis associated with increased hepatic oxidative stress that would be further reflected by increased plasma levels of the respiratory chain component, oxidized coenzyme Q9 ((ox)CoQ9). Adult male C57Bl/6 mice were randomly assigned to chow, high-fat (HF), or high-fat high-carbohydrate (HFHC) diets for 16 weeks. The chow and HF mice had free access to pure water, whereas the HFHC group received water with 55% fructose and 45% sucrose (wt/vol). The HFHC and HF groups had increased body weight, body fat mass, fasting glucose, and were insulin-resistant compared with chow mice. HF and HFHC consumed similar calories. Hepatic triglyceride content, plasma alanine aminotransferase, and liver weight were significantly increased in HF and HFHC mice compared with chow mice. Plasma cholesterol (P < 0.001), histological hepatic fibrosis, liver hydroxyproline content (P = 0.006), collagen 1 messenger RNA (P = 0.003), CD11b-F4/80+Gr1+ monocytes (P < 0.0001), transforming growth factor beta1 mRNA (P = 0.04), and alpha-smooth muscle actin messenger RNA (P = 0.001) levels were significantly increased in HFHC mice. Hepatic oxidative stress, as indicated by liver superoxide expression (P = 0.002), 4-hydroxynonenal, and plasma (ox)CoQ9 (P < 0.001) levels, was highest in HFHC mice. CONCLUSION: These findings demonstrate that nongenetically modified mice maintained on an HFHC diet in addition to developing obesity have increased hepatic ROS and a NASH-like phenotype with significant fibrosis. Plasma (ox)CoQ9 correlated with fibrosis progression. The mechanism of fibrosis may involve fructose inducing increased ROS associated with CD11b+F4/80+Gr1+ hepatic macrophage aggregation, resulting in transforming growth factor beta1-signaled collagen deposition and histologically visible hepatic fibrosis.

Systematic evaluation of muscle coenzyme Q10 content in children with mitochondrial respiratory chain enzyme deficiencies.

Coenzyme Q10 content, pathology evaluation, and electron transport chain (ETC) enzyme analysis were determined in muscle biopsy specimens of 82 children with suspected mitochondrial myopathy. Data were stratified into three groups: "probable" ETC defects, "possible" ETC defects, and disease controls. Muscle total, oxidized, and reduced coenzyme Q10 concentrations were significantly decreased in the probable defect group. Stepwise logistic regression indicated that only total coenzyme Q10 was significantly associated with probable ETC defect. Receiver operator characteristic (ROC) analysis suggested that total muscle coenzyme Q10 was the best predictor of an ETC complex abnormality. Determination of muscle coenzyme Q10 deficiency in children with suspected mitochondrial disease may facilitate diagnosis and encourage earlier supplementation of this agent.

Validation and application of an HPLC-EC method for analysis of coenzyme Q10 in blood platelets.

Previous studies have indicated that analysis of coenzyme Q10 (CoQ10) in platelets may be clinically useful. The study objectives are to describe, validate and provide application of an HPLC-EC method for platelet CoQ10 analysis. This method analyzes oxidized (ubiquinone-10) and reduced (ubiquinol-10) forms of CoQ10 using two separate injections with the electrochemical analytical cell set at neutral and oxidizing potentials. Results showed that chromatograms were free of interfering peaks. Calibration curves were constructed over a concentration range 116-2317 nmol/L (r(2) = 0.99). The extraction recovery was >95%. The within-run precision CV% was < or =4.2%, and the day-to-day precision was < or =9.9%. Platelets were isolated by differential centrifugation, and frozen at -70 degrees C until analysis. The application of the method was used to compare accumulation of CoQ10 in platelets vs plasma in eight adult volunteers during a 28 day supplementation period (5 mg/kg/day of ubiquinol-10). Mean platelet total CoQ10 was 164 pmol/10(9) cells, and ubiquinol-10:total CoQ10 ratio was 0.56. During supplementation platelet CoQ10 levels were more consistent and predictable than plasma CoQ10 levels. The results indicate that this validated method for platelet ubiquinol-10 and ubiquinone-10 analysis is acceptable for use in the clinical laboratory, and that platelet CoQ10 may have important advantages over plasma during CoQ10 supplementation.

The uptake and distribution of coenzyme Q10.

This review describes recent advances in our understanding of the uptake and distribution of coenzyme Q10 (CoQ10) in cells, animals, and humans. These advances have provided evidence of important pharmacokinetic factors, such as non-linear absorption and enterohepatic recirculation, and may facilitate the development of new CoQ10 formulations. Studies providing data which support the claim of tissue uptake of exogenous CoQ10 are also discussed. Improved CoQ10 dosing and drug level monitoring guidelines are suggested for adult and pediatric patient populations. Future CoQ10 research should consider uptake and distribution factors to determine cost-benefit relationships.

Coenzyme Q10 (ubiquinol-10) supplementation improves oxidative imbalance in children with trisomy 21.

Endogenous coenzyme Q10 is an essential cofactor in the mitochondrial respiratory chain, a potent antioxidant, and a potential biomarker for systemic oxidative status. Evidence of oxidative stress was reported in individuals with trisomy 21. In this study, 14 children with trisomy 21 had significantly increased (P < 0.0001) plasma ubiquinone-10 (the oxidized component of coenzyme Q10) compared with 12 age- and sex-matched healthy children (historical controls). Also, the mean ratio of ubiquinol-10 (the biochemically reduced component):total coenzyme Q10 was significantly decreased (P < 0.0001). After 3 months of ubiquinol-10 supplementation (10 mg/kg/day) to 10 patients with trisomy 21, the mean ubiquinol-10:total coenzyme Q10 ratio increased significantly (P < 0.0001) above baseline values, and 80% of individual ratios were within normal range. No significant or unexpected adverse effects were reported by participants. To our knowledge, this is the first study to indicate that the pro-oxidant state in plasma of children with trisomy 21, as assessed by ubiquinol-10:total coenzyme Q10 ratio, may be normalized with ubiquinol-10 supplementation. Further studies are needed to determine whether correction of this oxidant imbalance improves clinical outcomes of children with trisomy 21.

Coenzyme Q10 absorption and tolerance in children with Down syndrome: a dose-ranging trial.

Controlled studies of coenzyme Q(10) dosing and tolerance have been reported in adults, but not in pediatric patients. This study compares low- and high-dose coenzyme Q(10) (LiQ-NOL syrup) absorption and tolerance in children with Down syndrome. After a 1-month low-dose (1.0 mg/kg/day) run-in period, all participants received high-dose coenzyme Q(10) (10.0 mg/kg/day) for two additional months (in randomized sequence as one daily dose or split into two daily doses). Chemistry profiles and complete blood counts were determined just before and at the study completion. Plasma coenzyme Q(10) concentrations were determined initially and at each study visit. Parents reported adverse events and study drug evaluations using standardized forms. Most of the 16 children who completed this study tolerated high-dose coenzyme Q(10) well. Uncooperative behavior resulted in premature withdrawal of two participants, and may have been treatment-related. Pre- and posttreatment laboratory test changes were considered to be clinically nonsignificant. Study results indicate that high-dose coenzyme Q(10) (10 mg/kg/day) is well-absorbed and well-tolerated by most children with Down syndrome, and appears to provide plasma concentrations which are comparable to previous adult studies administering much higher coenzyme Q(10) dosages.

Ubiquinol: a potential biomarker for tissue energy requirements and oxidative stress.

BACKGROUND: Coenzyme Q (CoQ) has been suggested as a biomarker for tissue redox status. The aims are (1) to compare ubiquinol-9, ubiquinol-10, ubiquinone-9, ubiquinone-10, total CoQ content and CoQ redox ratio in quadriceps muscle, heart, brain and liver tissues of mdx mice with wild-type controls; and (2) to determine if ubiquinol content and CoQ redox ratio changes are associated with pathological findings in mdx mouse. METHODS: CoQ contents were determined in homogenized quadriceps muscle, heart, liver and brain of age-matched mdx and wild-type control mice by HPLC-EC. Light and electron microscopy studies were conducted using standard pathology methods. RESULTS: Ubiquinol-9 and ubiquinol-10 concentrations are significantly increased in quadriceps and heart muscle of mdx mouse. Increased redox ratios of coenzyme Q(9) and coenzyme Q(10) are also evident in quadriceps, heart and liver tissues in mdx mouse, but not brain. Pathological examination shows marked myofiber regeneration and evidence of mitochondrial proliferation for mdx muscle. CONCLUSIONS: Evidence that changes in ubiquinol content and CoQ redox ratio are related to pathological features in mdx skeletal and heart myofibers suggests that tissue ubiquinol content and CoQ redox ratio may be useful biomarkers for evaluating muscle disorders associated with mitochondrial proliferation and defects in oxidative phosphorylation.

Muscle coenzyme Q: a potential test for mitochondrial activity and redox status.

The aim of this study is to determine whether coenzyme Q (CoQ) muscle concentrations and redox state are associated with pathologic changes in muscle biopsy specimens. Skeletal muscle biopsies were collected (January 2002-February 2004) and underwent pathologic evaluation. Quadriceps specimens (n = 47) were stratified accordingly: Group 1, controls without evidence of pathologic abnormalities; Group 2, type I myofiber predominance; Group 3, type II myofiber atrophy; Group 4, lower motor unit disease; and Group 5, muscular dystrophy. Ubiquinol-10, ubiquinone-10, total coenzyme Q10 (CoQ10), coenzyme Q9 (CoQ9), total CoQ (CoQ9+CoQ10) concentrations were analyzed in biopsy muscle by high-performance liquid chromatography. Ubiquinone-10, total CoQ10, and total CoQ concentrations were significantly decreased in Group 5. Significant positive correlations (r congruent with 0.40) were found between muscle ubiquinone-10, total CoQ10, and total CoQ concentrations vs the percentage of myofibers having subsarcolemmal mitochondrial aggregates. CoQ redox ratio and the fraction CoQ9/total CoQ were negatively correlated with subsarcolemmal mitochondrial aggregates. A significant correlation (r = 0.328) also occurred between ubiquinol-10 concentration and citrate synthase activity. This study suggests that total CoQ concentration provides a new method for estimating mitochondrial activity in biopsy muscle; and that the muscle CoQ test is feasible and potentially useful for diagnosing CoQ deficiency states.

Clinical laboratory monitoring of coenzyme Q10 use in neurologic and muscular diseases.

Coenzyme Q10 (Q10) is available as an over-the-counter dietary supplement in the United States. While its use could be considered a form of alternative therapy, the medical profession has embraced the use of Q10 in specific disease states, including a series of neurologic and muscular diseases. Clinical laboratory monitoring is available for measurement of total Q10 in plasma and tissue and for measurement of redox status, ie, the ratio of reduced and oxidized forms of Q10. Many published studies have been anecdotal, in part owing to the rarity of some diseases involved. Unfortunately, many studies do not report Q10 levels, and, thus, the relationship of clinical response to Q10 concentration in plasma frequently is not discernible. Consistent laboratory monitoring of patients treated with this compound would help ease interpretation of the results of the treatment, especially because so many formulations of Q10 exist in the marketplace, each with its own bioavailability characteristics. Q10 has an enviable safety profile and, thus, is ideal to study as an adjunct to more conventional therapy. Defining patient subpopulations and characteristics that predict benefit from exogenous Q10 and defining therapeutic ranges for those particular applications are major challenges in this field.

Anticoagulant effects on plasma coenzyme Q(10) estimated by HPLC with coulometric detection.

BACKGROUND: The proportion of reduced coenzyme Q(10) (Q(10)H(2)) in total coenzyme Q(10) (TQ(10)), referred to as the Q(10)H(2):TQ(10) ratio, may be used as a possible marker of in vivo oxidative stress. However, the ranges for Q(10)H(2):TQ(10) ratio from previous reports are quite variable. Sample handling and preparation appear to have a profound effect on the stability of Q(10)H(2). METHODS: Paired tests were used to estimate TQ(10), Q(10)H(2), oxidized coenzyme Q(10) (Q(10)), and Q(10)H(2):TQ(10) ratio in patient samples collected in vacutainers containing heparin or EDTA. Sample tubes were immediately placed on ice and promptly centrifuged. After harvesting plasma, 100 microl of plasma was extracted with 1-propanol and centrifuged. The supernatant was injected directly into a high-performance liquid chromatography (HPLC) system. RESULTS: Significantly higher values (p=0.0015) of TQ(10), Q(10)H(2), and Q(10)H(2):TQ(10) ratio were noted in heparinized plasma as compared to EDTA plasma; Q(10) concentrations were lower in heparinized plasma. When vacutainers containing specimen were opened and kept refrigerated, the Q(10)H(2):TQ(10) ratios in heparinized samples were stable over 7 h with variation <3%. Blood Q(10)H(2) in closed heparin vacutainers kept refrigerated was stable up to 24 h. CONCLUSIONS: Our results indicate that the heparinized plasma is superior to the EDTA plasma in all measurements for coenzyme Q(10).

Coenzyme Q10 changes are associated with metabolic syndrome.

BACKGROUND: The purpose of this study was to determine whether coenzyme Q10 (CoQ) concentrations and redox status are associated with components of the metabolic syndrome. METHODS: This is a cross-sectional survey of 223 adults (28-78 years), who were drawn from the ongoing Princeton Follow-up Study in greater Cincinnati. Individuals were assessed for measures of fatness, blood pressure, glucose, lipid profiles, C-reactive protein (CRP), reduced CoQ (ubiquinol), oxidized CoQ (ubiquinone), total CoQ and CoQ redox ratio (ubiquinol/ubiquinone). RESULTS: After adjusting for age, sex and race, we found that total CoQ, ubiquinol and CRP levels are significantly increased in metabolic syndrome. Comparison of minimal risk and high-risk metabolic syndrome groups indicates an increased CoQ redox ratio in the high risk group (p<0.05). Step-wise logistic regression analysis, using age, sex, race, (ln)CRP, total cholesterol, LDL, ubiquinol, ubiquinone and total CoQ as predictors, shows that only age (p=0.001), total CoQ adjusted for plasma lipids (p<0.0001) and (ln)CRP (p<0.005) were significant predictors of metabolic syndrome. CONCLUSIONS: The presence of metabolic syndrome components are associated with increased plasma total CoQ and ubiquinol concentrations after adjusting for age, sex and race. An increase in CoQ redox ratio may indicate a gender-specific adaptive response to oxidative stress in females, but not males.

Measurement of reduced and oxidized coenzyme Q9 and coenzyme Q10 levels in mouse tissues by HPLC with coulometric detection.

BACKGROUND: Ubiquinone-responsive multiple respiratory chain dysfunction due to coenzyme Q(10) (CoQ(10)) deficiency has been previously identified in muscle biopsies. However, previous methods are unreliable for estimating CoQ(10) redox status in tissue. We developed an accurate method for measuring tissue concentrations of reduced and oxidized coenzyme Q (CoQ). METHODS: Mouse tissues were weighed in the frozen state and homogenized with cold 1-propanol on ice. After solvent extraction, centrifugation and filtration, the filtrate was subsequently analyzed by reversed-phase HPLC with coulometric detection. RESULTS: Reference calibration curves were used to determine reduced and oxidized coenzyme Q(9) (CoQ(9)) and CoQ(10) concentrations in tissues. The method is sensitive ( approximately 15 microg/l), reproducible (6% CV) for CoQ(9) and CoQ(10), and linear up to 20 mg/l for CoQ(9) and CoQ(10). Analytical recoveries were 90-104%. In mouse tissues the amounts of total CoQ (TQ) ranged from 261 to 1737 nmol/g of protein. Total CoQ(9) levels are comparable with the values of those previously reported. CoQ is found to be mostly in the reduced form in mouse liver ( approximately 87%), heart ( approximately 60%), and muscle tissues ( approximately 58%); in the brain, most of the CoQ is in the oxidized state ( approximately 65%). CONCLUSION: This procedure provides a precise, sensitive, and direct assay method for the determination of reduced and oxidized CoQ(9) and CoQ(10) in mouse hindleg muscle, heart, brain, and liver tissues.

Age-related changes in plasma coenzyme Q10 concentrations and redox state in apparently healthy children and adults.

BACKGROUND: Coenzyme Q10 (CoQ) is an endogenous enzyme cofactor, which may provide protective benefits as an antioxidant. Because age-related CoQ changes and deficiency states have been described, there is a need to establish normal ranges in healthy children. The objectives of this study are to determine if age-related differences in reduced CoQ (ubiquinol), oxidized CoQ (ubiquinone), and CoQ redox state exist in childhood, and to establish reference intervals for these analytes in healthy children. METHODS: Apparently healthy children (n=68) were selected from individuals with no history of current acute illness, medically diagnosed disease, or current medication treatment. Self-reported healthy adults (n=106) were selected from the ongoing Princeton Follow-up Study in greater Cincinnati. Participants were assessed for lipid profiles, ubiquinol concentration, ubiquinone concentration, total CoQ concentration, and CoQ redox ratio. RESULTS: Mean total CoQ and ubiquinol concentrations are similar in younger children (0.2-7.6 years) and adults (29-78 years); however, lipid-adjusted total CoQ concentrations are significantly increased in younger children. Also CoQ redox ratio is significantly increased in younger and older children compared with adults. CONCLUSIONS: Elevated CoQ and redox ratios in children may be an indication of oxidative stress effects, which are associated with early development of coronary heart disease.

Plasma coenzyme Q10 reference intervals, but not redox status, are affected by gender and race in self-reported healthy adults.

BACKGROUND: Abnormal concentrations of coenzyme Q(10) have been reported in many patient groups, including certain cardiovascular, neurological, hematological, neoplastic, renal, and metabolic diseases. However, controls in these studies are often limited in number, poorly screened, and inadequately evaluated statistically. The purpose of this study is to determine the reference intervals of plasma concentrations of ubiquinone-10, ubiquinol-10, and total coenzyme Q(10) for self-reported healthy adults. METHODS: Adults (n=148), who were participants in the Princeton Prevalence Follow-up Study, were identified as healthy by questionnaire. Lipid profiles, ubiquinone-10, ubiquinol-10, and total coenzyme Q(10) concentrations were measured in plasma. The method used to determine the reference intervals is a procedure incorporating outlier detection followed by robust point estimates of the appropriate quantiles. RESULTS: Significant differences between males and females were present for ubiquinol-10 and total coenzyme Q(10). Blacks had significantly higher Q(10) measures than whites in all cases except for the ubiquinol-10/total Q(10) fraction. CONCLUSIONS: The fraction of ubiquinol-10/total coenzyme Q(10) is a tightly regulated measure in self-reported healthy adults, and is independent of sex and racial differences. Different reference intervals for certain coenzyme Q(10) measures may need to be established based upon sex and racial characteristics.

Correlation of lamotrigine concentrations between serum and saliva.

STUDY OBJECTIVE: To compare the relationship between serum and salivary concentrations of lamotrigine in pediatric and adult epilepsy populations. DESIGN: Paired-sample pharmacokinetic study. SETTING: University neurology clinic. PATIENTS: Thirty-seven patients with epilepsy, aged 2-60 years, who were taking lamotrigine and whose physicians had ordered a lamotrigine serum concentration. MEASUREMENTS AND MAIN RESULTS: Patients spit a minimum of 0.25 ml into a cup to provide saliva samples. Blood samples were obtained by phlebotomy. Serum and salivary lamotrigine concentrations were determined by high-performance liquid chromatography. Linear regression analysis was used to evaluate correlations. Six patients' results were omitted due to the lack of a serum or saliva specimen or clearly erroneous results, leaving 31 patients for analysis. There was a strong correlation between the serum results reported by two reference laboratories (coefficient of correlation [r] = 0.988). The correlations between salivary and serum lamotrigine concentrations were similar for reference laboratory A (r = 0.81) and reference laboratory B (r = 0.84). Saliva:serum concentration ratios ranged from 0.41-1.26 (mean +/- SD 0.62 +/- 0.19) for reference laboratory A and from 0.40-1.19 ((mean +/- SD 0.64 +/- 0.18) for reference laboratory B. CONCLUSION: There is a good correlation between salivary and serum concentrations for lamotrigine. However, there is wide interpatient variability in the saliva:serum ratio. The data suggest that salivary monitoring may play a role in the monitoring of lamotrigine for adult and pediatric patients.

Topiramate concentration in saliva: an alternative to serum monitoring.

This study examines the relationship between serum and saliva topiramate concentrations, and attempts to determine if saliva may be a useful alternative to serum for therapeutic monitoring. Saliva and blood specimens were collected from 31 epilepsy patients (mean age 10.5 +/- 6.0 years; range 2.5 years to 24.8 years), and topiramate concentrations were determined by fluorescence polarization immunoassay. One patient's results were omitted because the saliva concentration was below the limit of quantitation of the assay. A strong correlation exists between serum and saliva topiramate concentrations (adjusted r(2) = 0.97, n = 30, P < 0.0001). The mean fraction of saliva to serum concentration is 89.8% +/- 12.1% (range 62.9% to 112.7%). The results of this study support the use of saliva as a viable alternative to serum for monitoring topiramate therapy. Topiramate concentration in saliva: an alternative to serum monitoring.

Interaction between akt1-positive neurons and age at surgery is associated with surgical outcome in children with isolated focal cortical dysplasia.

To identify pathologic characteristics that are associated with outcome, we performed a retrospective analysis of the clinical, radiologic, and pathologic features of 44 children with isolated focal cortical dysplasia (FCD) after epilepsy surgery. Based on the International League Against Epilepsy Classification, 16 patients had FCD Type I and 28 subjects had FCD Type II. A significantly higher percentage of subjects with FCD Type IIb versus Types I and IIa were seizure-free after surgery. Akt (also known as protein kinase B) is the main downstream target of phosphatidylinositol 3'-kinase and has been implicated in epilepsy pathogenesis. Semiquantitative analysis of cortical gliosis and quantitation of Akt1-immunoreactive neurons indicated that individuals with FCD Type II were more likely to have diffuse astrogliosis and higher counts of Akt1-positive neurons versus those with FCD Type I. A logistic regression model, including Akt1-positive neurons, age at surgery, and the interaction of these factors, was significantly associated with seizure-free outcome. This study provides evidence that astrogliosis and overexpression of neuronal Akt1 protein may be important factors in the pathogenesis of FCD and suggests that the pathogenesis of FCD Type I may differ from that of FCD Type II in children.

Measurement of oxidized and reduced coenzyme Q in biological fluids, cells, and tissues: an HPLC-EC method.

Direct measure of coenzyme Q (CoQ) in biological specimens may provide important advantages. Precise and selective high-performance liquid chromatography (HPLC) methods with electrochemical (EC) detection have been developed for the measurement of reduced (ubiquinol) and oxidized (ubiquinone) CoQ in biological fluids, cells, and tissues. EC detection is preferred for measurement of CoQ because of its high sensitivity. Reduced and oxidized CoQ are first extracted from biological specimens using 1-propanol. After centrifugation, the 1-propanol supernatant is directly injected into HPLC and monitored at a dual-electrode. The EC reactions occur at the electrode surface. The first electrode transforms ubiquinone into ubiquinol, and the second electrode measures the current produced by the oxidation of the hydroquinone group of ubiquinol. The methods described provide rapid, precise, and simple procedures for determination of reduced and oxidized CoQ in biological fluids, cells, and tissues. The methods have been successfully adapted to meet regulatory requirements for clinical laboratories, and have been proven reliable for analysis of clinical and research samples for clinical trials and animal studies involving large numbers of specimens.