A potential role of nettle (Urtica dioica) extract on growth, biochemical changes and reproductive performance of convict cichlid (Amatitlania nigrofasciata).

This study was carried out to investigate the effects of methanolic extract of nettle (Urtica dioica) on growth, reproduction, biochemical and immunological parameters of female convict cichlid (Amatitlania nigrofasciata). For this purpose, 54 fish were distributed in 3 treatments included: without supplementation (control), 0.1 g (NE0.1), and 0.5 g (NE0.5) nettle extract per kilogram feed over 56 days. The highest final weight (4.2 ± 0.1 g), weight gain (2.8 ± 0.1 g), and specific growth rate (2.0 ± 0.0% day-1) were recorded in NE0.1 group. Higher and lower feed conversion ratio were obtained in control and NE0.1 treatments, respectively. Hepatosomatic and viscerosomatic indices in NE0.1 treatment were significantly lower compared with control treatment. Fish fed NE0.1 showed significantly lower glucose (55.2 ± 6.5 mg g-1), cholesterol (28.4 ± 3.3 mg g-1), and triglyceride (211.5 ± 39.0 mg g-1) levels. Total protein (36.3 ± 3.4 mg g-1) and albumin (2.7 ± 0.1 mg g-1) showed a marked increase in NE0.1 treatment. Same trend was observed in C3, C4, and IgM concentrations. NE0.1 showed the highest number of eggs per female (183.7 ± 10.2), hatching rate (97 ± 0.7%), and larval survival rate at 3 days post hatch (86.3 ± 0.6%) compared with the other treatments. These findings indicated that 0.1 g methanolic extract of nettle kg feed-1 could enhance growth, improve metabolic, and immune function of convict cichlid. Moreover, this study confirmed that appropriate dose of nettle can positively promote reproductive performance which makes it as a valuable and cost-effective herb in aquaculture industry.

The effects of varying doses of caffeine on cardiac parasympathetic reactivation following an acute bout of anaerobic exercise in recreational athletes.

BACKGROUND: To examine the effects of varying doses of caffeine on autonomic reactivation following anaerobic exercise. METHODS: Recreationally active males (N = 20; 24 ± 2y) participated in a randomized, double-blind, placebo-controlled, crossover study where participants ingested: [1] Control (CON; no supplement), [2] a non-caffeinated placebo (PLA), [3] 3-mg∙kg- 1 of caffeine (CAF3) or [4] 6-mg∙kg- 1 of caffeine (CAF6) prior to Wingate testing. Parasympathetic (lnRMSSD, primary outcome) and global HRV (lnSDNN, secondary outcome) were assessed at rest (i.e., pre-ingestion), 45-min post-ingestion, and 5-min and 35-min post-exercise recovery. We used a GLM to assess mean (95% CI) changes from pre-ingestion baseline. RESULTS: Overall, we observed a significant trend for lnRMSSD and lnSDNN (both, p = 0.001, ηp2 = 0.745). Forty-five minutes after treatment ingestion, we observed a significant increase in lnRMSSD for CAF3 (0.15 ms, 95%CI, 0.07,0.24) and CAF6 (0.16 ms, 95%CI, 0.06,0.25), both being significant (both, p <  0.004) vs. CON (- 0.02 ms, 95%CI, - 0.09,0.04). Five-minutes after exercise, all treatments demonstrated significant declines in lnRMSSD vs. baseline (all, p <  0.001). After 35-min of recovery, lnRMSSD returned to a level not significantly different than baseline for CAF3 (0.03 ms, 95%CI, - 0.05, 0.12) and CAF6 (- 0.03 ms, 95%CI, - 0.17, 0.10), while PLA (- 0.16 ms, 95%CI, - 0.25, - 0.06) and CON (- 0.17 ms, 95%CI, - 0.28, - 0.07) treatments remained significantly depressed. A similar pattern was also observed for SDNN. CONCLUSION: Caffeine ingestion increases resting cardiac autonomic modulation and accelerates post-exercise autonomic recovery after a bout of anaerobic exercise in recreationally active young men. However, no differences between caffeine doses on cardiac autonomic reactivity were observed.

Stimulatory effects of short-term calcitonin administration on plasma calcium, magnesium, phosphate, and glucose in juvenile Siberian sturgeon Acipenser baerii.

Calcitonin (CT) has a potential function in calcium (Ca) regulation, but there are conflicting observations in fishes. Because of the lack of calcified endoskeleton, sturgeons have low Ca circulating compared with teleost fish and the function of CT on Ca in sturgeon is very less understood. The purpose of this study was to investigate the impact of injection of salmon CT on plasma Ca, magnesium (Mg), phosphate (PHO), and glucose levels of juvenile Siberian sturgeon Acipenser baerii. Sixteen-month-old fish (429.6 ± 12.1 g) were intraperitoneally injected with a single dose of CT (5 µg kg-1 BW) and saline solution as a control group. Thereafter, blood sampling was performed at 0, 1, 2, 4, 6, 12, 24, and 48 h after injection. CT produced marked increases in all variables measured. The highest levels of Ca (6.77 ± 0.53 mg dL-1), Mg (9.79 ± 0.16 mg dL-1) and PHO (1.74 ± 0.05 mg dL-1) were recorded at 2 h after CT injection and showed significant difference compared with control treatment (Ca 4.75 ± 0.12 mg dL-1; Mg 5.47 ± 0.16 mg dL-1 and PHO 1.23 ± 0.06 mg dL-1). It also likely produced hyperglycemia. However, the differences with the controls were not statistically significant, possibly due to interference with the hyperglycemia induced by the stress of injection. Our results showed that the injection of 5 µg kg-1 BW CT to Siberian sturgeon has an incremental effect on plasma Ca, Mg, and PHO. The increase in plasma Ca level indicated that CT has a potent hypercalcemic effect in sturgeon under laboratory condition, in contrast to the hypocalcemic effects reported for teleosts.

High neurofilament levels are associated with clinically definite multiple sclerosis in children and adults with clinically isolated syndrome.

BACKGROUND: A promising biomarker for axonal damage early in the disease course of multiple sclerosis (MS) is neurofilament light chain (NfL). It is unknown whether NfL has the same predictive value for MS diagnosis in children as in adults. OBJECTIVE: To explore the predictive value of NfL levels in cerebrospinal fluid (CSF) for MS diagnosis in paediatric and adult clinically isolated syndrome (CIS) patients. METHODS: A total of 88 adult and 65 paediatric patients with a first attack of demyelination were included and followed (mean follow up-time in adults: 62.8 months (standard deviation (SD) ±38.7 months) and 43.8 months (SD ±27.1 months) in children). Thirty control patients were also included. Lumbar puncture was done within 6 months after onset of symptoms. NfL was determined in CSF using enzyme-linked immunosorbent assay (ELISA). COX regression analyses were used to calculate hazard ratios (HR) for clinically definite multiple sclerosis (CDMS) diagnosis. RESULTS: After adjustments for age, oligoclonal bands (OCB), and asymptomatic T2 lesions on baseline magnetic resonance imaging (MRI), increased NfL levels in both paediatric and adult CIS patients were associated with a shorter time to CDMS diagnosis (children HR = 3.7; p = 0.007, adults HR = 2.1; p = 0.032). For CIS patients with a future CDMS diagnosis, children showed higher NfL levels than adults (geometric mean 4888 vs 2156 pg/mL; p = 0.007). CONCLUSION: CSF NfL levels are associated with CDMS diagnosis in children and adults with CIS. This makes NfL a promising predictive marker for disease course with potential value in clinical practice.

Application of the 2017 Revised McDonald Criteria for Multiple Sclerosis to Patients With a Typical Clinically Isolated Syndrome.

Importance: In 2017, the International Panel on Diagnosis of Multiple Sclerosis revised the McDonald 2010 criteria for the diagnosis of multiple sclerosis (MS). The new criteria are easier to apply and could lead to more and earlier diagnoses. It is important to validate these criteria globally for their accuracy in clinical practice. Objective: To evaluate the diagnostic accuracy of the 2017 criteria vs the 2010 criteria in prediction of clinically definite MS in patients with a typical clinically isolated syndrome (CIS). Design, Setting and Patients: A total of 251 patients at Erasmus MC, Rotterdam, the Netherlands, in collaboration with several regional hospitals, fulfilled the inclusion criteria. Thirteen patients received another diagnosis early in the diagnostic process and therefore were excluded from the analyses. Nine patients with CIS declined to participate in the study. This left 229 patients who were included between March 2006 and August 2016 in this prospective CIS cohort. Patients underwent a baseline magnetic resonance imaging scan within 3 months after onset of symptoms and, if clinically required, a lumbar puncture was performed. Data were analyzed between December 2017 and January 2018. Main Outcomes and Measures: Sensitivity, specificity, accuracy, and positive and negative predictive value were calculated after 1, 3, and 5 years for the 2017 vs the 2010 criteria. Results: Among the 229 patients with CIS, 167 were women (73%), and the mean (SD) age was 33.5 (8.2) years. One hundred thirteen patients (49%) were diagnosed as having CDMS during a mean (SD) follow-up time of 65.3 (30.9) months. Sensitivity for the 2017 criteria was higher than for the 2010 criteria (68%; 95% CI, 57%-77% vs 36%; 95% CI, 27%-47%; P < .001), but specificity was lower (61%; 95% CI, 50%-71% vs 85%; 95% CI, 76%-92%; P < .001). Using the 2017 criteria, more MS diagnoses could be made at baseline (n = 97 [54%]; 95% CI, 47%-61% vs n = 46 [26%]; 95% CI, 20%-32%; P < .001). In the group with at least 5 years of follow-up, 33% of patients who were diagnosed as having MS using the 2017 criteria did not experience a second attack during follow-up vs 23% when using the 2010 criteria. Conclusions and Relevance: The 2017 revised McDonald criteria are associated with greater sensitivity but less specificity for a second attack than the previous 2010 criteria. The tradeoff is that it leads to a higher number of MS diagnoses in patients with a less active disease course.

Growth performance and plasma metabolites in juvenile Siberian sturgeon Acipenser baerii (Brandt, 1869) subjected to various feeding strategies at different sizes.

The effect of various feeding strategies was evaluated on growth performance and biochemical parameters in two sizes of Siberian sturgeon (465.75 ± 11.18 and 250.40 ± 12 g) during 45 days. Fish were distributed into six experimental treatments including large fish with satiation feeding (LA), small fish with satiation feeding (SA), large fish with 50% satiation feeding (LR), small fish with 50% satiation feeding (SR), large starved fish (LS), and small starved fish (SS). Differences in final weight between LA and LR treatments were not noticeable, whereas SA and SR treatments showed significant differences. Growth parameters were more affected in small fish. In condition factor and weight gain in starved treatments, a considerable reduction occurred by interaction between feeding strategies and fish size, so the lowest values were obtained in SS treatment. Glucose levels significantly decreased in small fish during the starvation. Interaction between feeding strategy and fish size indicated the highest and lowest albumin level in SA and SS treatment, respectively. Cholesterol, triglyceride, total protein, and globulin showed no significant differences. It can be deduced that small fish are more sensitive to starvation than the large fish. Since glucose and albumin showed significant decrease in starved small fish, these parameters can help to monitor nutritional status and feeding practices. It was indicated that in both sizes of Siberian sturgeon, feeding 50% satiation reduced the food cost without negative impact on physiological condition, and it can be considered as an appropriate strategy to face unfavorable circumstances.

Fatigue after a first attack of suspected multiple sclerosis.

BACKGROUND: Fatigue is reported by more than 75% of multiple sclerosis (MS) patients. In an earlier study, we showed that fatigue is not only a common symptom in patients at time of clinically isolated syndrome (CIS; fatigued 46%) but also predicts subsequent diagnosis of clinically definite multiple sclerosis (CDMS). The course of fatigue after CIS is unknown. OBJECTIVE: We aimed to explore the long-term course of fatigue after CIS. METHODS: In this study, 235 CIS patients, aged 18-50 years, were prospectively followed. Patients filled in the Krupp's Fatigue Severity Scale (FSS) and the Hospital Anxiety and Depression Scale (HADS) at baseline and annually. After reaching CDMS diagnosis, Expanded Disability Status Scale (EDSS) was obtained annually. Mixed-effects models were used to analyse longitudinal FSS measurements. RESULTS: Fatigue at baseline was an independent predictor for CDMS diagnosis (hazard ratio (HR): 2.6, 95% confidence interval (CI): 1.6-4.4). The evolution of FSS was the same in CIS patients who remained monophasic and patients who were diagnosed with CDMS during follow-up. However, FSS increased by 0.86 units after reaching CDMS diagnosis ( p = 0.01). After this increase, the FSS course remained unaltered ( p = 0.44). CONCLUSION: Fatigue, which is often present at time of CIS, probably persists over time and increases after a second attack.

Soluble CD27 Levels in Cerebrospinal Fluid as a Prognostic Biomarker in Clinically Isolated Syndrome.

Importance: There is a growing number of therapies that could be administered after the first symptom of central nervous system demyelination. These drugs can delay multiple sclerosis (MS) diagnosis and slow down future disability. However, treatment of patients with benign course may not be needed; therefore, there is a need for biomarkers to predict long-term prognosis in patients with clinically isolated syndrome (CIS). Objective: To investigate whether the T-cell activation marker soluble CD27 (sCD27) measured in cerebrospinal fluid of patients at time of a first attack is associated with a subsequent diagnosis of MS and a higher relapse rate. Design, Setting, and Participants: This prospective study included 77 patients with CIS between March 2002 and May 2015 in a tertiary referral center for multiple sclerosis, in collaboration with several regional hospitals. Patients with CIS underwent a lumbar puncture and magnetic resonance imaging scan within 6 months after first onset of symptoms. Main Outcomes and Measures: Soluble CD27 levels were determined in cerebrospinal fluid using a commercially available enzyme-linked immunosorbent assay. Cox regression analyses was used to calculate univariate and multivariate hazard ratios for MS diagnosis. Association between sCD27 levels and relapse rate was assessed using a negative binomial regression model. Results: Among 77 patients with CIS, 50 were female (79.5%), and mean (SD) age was 32.7 (7.4) years. Mean (SD) age in the control individuals was 33.4 (9.5) years, and 20 were female (66.7%).Patients with CIS had higher cerebrospinal fluid sCD27 levels than control individuals (geometric mean, 31.3 U/mL; 95% CI, 24.0-40.9 vs mean, 4.67 U/mL; 95% CI, 2.9-7.5; P < .001). During a mean (SD) follow-up of 54.8 (35.1) months, 39 of 77 patients (50.6%) were diagnosed as having MS. In a model adjusted for magnetic resonance imaging and cerebrospinal fluid measurements, sCD27 levels were associated with a diagnosis of MS (hazard ratio, 2.4 per 100 U/mL increase in sCD27 levels; 95% CI, 1.27-4.53; P = .007). Additionally, patients with MS with high sCD27 levels (median, >31.4 U/mL) at the time of CIS had a 5.5 times higher annualized relapse rate than patients with low sCD27 levels (annualized relapse rate, 0.06 vs 0.33; P = .02). Conclusions and Relevance: Soluble CD27 in cerebrospinal fluid of patients with CIS was associated with MS diagnosis and a high relapse rate. Therefore, sCD27 is an activation molecule directly related to the immunopathology of the disease and is a potential clinical marker to help in treatment decisions after a first attack of suspected MS.

Chitinase 3-like 1: prognostic biomarker in clinically isolated syndromes.

Chitinase 3-like 1 (CHI3L1) has been proposed as a biomarker associated with the conversion to clinically definite multiple sclerosis in patients with clinically isolated syndromes, based on the finding of increased cerebrospinal fluid CHI3L1 levels in clinically isolated syndrome patients who later converted to multiple sclerosis compared to those who remained as clinically isolated syndrome. Here, we aimed to validate CHI3L1 as a prognostic biomarker in a large cohort of patients with clinically isolated syndrome. This is a longitudinal cohort study of clinically isolated syndrome patients with clinical, magnetic resonance imaging, and cerebrospinal fluid data prospectively acquired. A total of 813 cerebrospinal fluid samples from patients with clinically isolated syndrome were recruited from 15 European multiple sclerosis centres. Cerebrospinal fluid CHI3L1 levels were measured by enzyme-linked immunosorbent assay. Multivariable Cox regression models were used to investigate the association between cerebrospinal fluid CHI3L1 levels and time to conversion to multiple sclerosis and time to reach Expanded Disability Status Scale 3.0. CHI3L1 levels were higher in patients who converted to clinically definite multiple sclerosis compared to patients who continued as clinically isolated syndrome (P = 8.1 × 10(-11)). In the Cox regression analysis, CHI3L1 levels were a risk factor for conversion to multiple sclerosis (hazard ratio = 1.7; P = 1.1 × 10(-5) using Poser criteria; hazard ratio = 1.6; P = 3.7 × 10(-6) for McDonald criteria) independent of other covariates such as brain magnetic resonance imaging abnormalities and presence of cerebrospinal fluid oligoclonal bands, and were the only significant independent risk factor associated with the development of disability (hazard ratio = 3.8; P = 2.5 × 10(-8)). High CHI3L1 levels were associated with shorter time to multiple sclerosis (P = 3.2 × 10(-9) using Poser criteria; P = 5.6 × 10(-11) for McDonald criteria) and more rapid development of disability (P = 1.8 × 10(-10)). These findings validate cerebrospinal fluid CHI3L1 as a biomarker associated with the conversion to multiple sclerosis and development of disability and reinforce the prognostic role of CHI3L1 in patients with clinically isolated syndrome. We propose that determining cerebrospinal fluid chitinase 3-like 1 levels at the time of a clinically isolated syndrome event will help identify those patients with worse disease prognosis.

Fatigue at time of CIS is an independent predictor of a subsequent diagnosis of multiple sclerosis.

OBJECTIVE: Fatigue is a common, disabling symptom of multiple sclerosis (MS), but little is known about fatigue in patients with clinically isolated syndrome (CIS), often the presenting symptom of MS. We aimed to investigate the prevalence and severity of fatigue in patients with CIS, and its association with a diagnosis of clinically definite MS (CDMS). METHODS: 127 patients were consecutively included in our ongoing prospective CIS study. At baseline, clinical, demographic, laboratory and MRI data were collected, and fatigue severity was assessed using Krupp's Fatigue Severity Scale (FSS); fatigue was defined as FSS≥5.0. Fatigue scores were compared with scores of 113 healthy controls and with scores from the literature. The association of fatigue with CDMS was calculated using Cox regression models. RESULTS: The mean FSS of patients with CIS was 4.3, similar to MS patients, and significantly higher than that of healthy individuals (p<0.001). Fatigue prevalence in patients with CIS (46.5%) was significantly higher than in controls (p<0.001). Fifty-two patients (40.9%) reached CDMS during follow-up. Fatigue was associated with a diagnosis of CDMS in univariate analysis (HR 2.6, 95% CI 1.5 to 4.6) and in multivariate analysis correcting for sex, age, neuroanatomical localisation of CIS, 25-OH-vitamin D, anxiety, depression, MRI dissemination in space and gadolinium enhancement (HR 4.5, 95% CI 1.9 to 10.6). CONCLUSIONS: Already at the stage of CIS, fatigue is a very common symptom, with a severity similar to fatigue in MS patients. This fatigue seems unrelated to the type or severity of the attack. Importantly, we found that fatigue was an independent predictor of a subsequent diagnosis of MS.

Perspectives on the use of multiple sclerosis risk genes for prediction.

OBJECTIVE: A recent collaborative genome-wide association study replicated a large number of susceptibility loci and identified novel loci. This increase in known multiple sclerosis (MS) risk genes raises questions about clinical applicability of genotyping. In an empirical set we assessed the predictive power of typing multiple genes. Next, in a modelling study we explored current and potential predictive performance of genetic MS risk models. MATERIALS AND METHODS: Genotype data on 6 MS risk genes in 591 MS patients and 600 controls were used to investigate the predictive value of combining risk alleles. Next, the replicated and novel MS risk loci from the recent and largest international genome-wide association study were used to construct genetic risk models simulating a population of 100,000 individuals. Finally, we assessed the required numbers, frequencies, and ORs of risk SNPs for higher discriminative accuracy in the future. RESULTS: Individuals with 10 to 12 risk alleles had a significantly increased risk compared to individuals with the average population risk for developing MS (OR 2.76 (95% CI 2.02-3.77)). In the simulation study we showed that the area under the receiver operating characteristic curve (AUC) for a risk score based on the 6 SNPs was 0.64. The AUC increases to 0.66 using the well replicated 24 SNPs and to 0.69 when including all replicated and novel SNPs (n = 53) in the risk model. An additional 20 SNPs with allele frequency 0.30 and ORs 1.1 would be needed to increase the AUC to a slightly higher level of 0.70, and at least 50 novel variants with allele frequency 0.30 and ORs 1.4 would be needed to obtain an AUC of 0.85. CONCLUSION: Although new MS risk SNPs emerge rapidly, the discriminatory ability in a clinical setting will be limited.

The association between cigarette smoking and multiple sclerosis.

Genetic factors partially explain the susceptibility of multiple sclerosis (MS) and might even relate to the clinical course. Still, many epidemiological studies point at an important role for environmental factors in MS. Smoking is one of the major candidates. In this review we provide an overview of the epidemiological studies on cigarette smoking and the association on MS risk and MS clinical course. In addition, we discuss the possible biological pathways that may influence neurological damage in MS. Moreover, the relation of smoking with other environmental MS risk factors will be addressed.

Infectious mononucleosis-linked HLA class I single nucleotide polymorphism is associated with multiple sclerosis.

BACKGROUND: Multiple sclerosis is a presumed autoimmune disease associated with genetic and environmental risk factors such as infectious mononucleosis. Recent research has shown infectious mononucleosis to be associated with a specific HLA class I polymorphism. OBJECTIVES: Our aim was to test if the infectious mononucleosis-linked HLA class I single nucleotide polymorphism (rs6457110) is also associated with multiple sclerosis. METHODS: Genotyping of the HLA-A single nucleotide polymorphism rs6457110 using TaqMan was performed in 591 multiple sclerosis cases and 600 controls. The association of multiple sclerosis with the HLA-A single nucleotide polymorphism was tested using logistic regression adjusted for age, sex and HLA-DRB1*1501. RESULTS: HLA-A minor allele (A) is associated with multiple sclerosis (OR = 0.68; p = 4.08 × 10( -5)). After stratification for HLA-DRB1*1501 risk allele (T) carrier we showed a significant OR of 0.70 (p = 0.003) for HLA-A. CONCLUSIONS: HLA class I single nucleotide polymorphism rs6457110 is associated with infectious mononucleosis and multiple sclerosis, independent of the major class II allele, supporting the hypothesis that shared genetics may contribute to the association between infectious mononucleosis and multiple sclerosis.

No evidence for intrathecal IgG synthesis to Epstein Barr virus nuclear antigen-1 in multiple sclerosis.

BACKGROUND: Recent studies suggest an intrathecal IgG response against Epstein Barr virus (EBV) in multiple sclerosis (MS), implicating a pathogenic role for the virus in MS. OBJECTIVES: To determine the spectrum of anti-EBV antibodies and B-cell epitopes within EBV nuclear antigen-1 (EBNA-1). Furthermore, to determine whether EBNA-1-specific IgG is produced intrathecally. STUDY DESIGN: Immunoblot analysis was used to study the anti-EBV IgG response in serum and cerebral spinal fluid (CSF) in MS and controls. EBNA-1 B-cell epitopes were identified by immunoscreening of 12 residue long peptides, with 11 residue overlap, spanning EBNA-1. Thirteen peptides containing all immunoreactive regions were constructed and used in paired serum and CSF of MS patients (n=17) and controls (n=18). Subsequently, reactivity to the identified immunodominant peptide was analysed in a large cohort of serum and CSF of MS patients (n=114) and disease controls (n=62). RESULTS: No difference was observed in the overall anti-EBV antibody diversity, but EBNA-1 reactivity was increased in MS patients versus controls for immunoblot and ELISA (p<0.0001). Epitope analysis on EBNA-1 revealed one immunodominant region covering residues 394-451: EBNA-1(394-451). Anti-EBNA-1(394-451) IgG levels in serum and CSF were significantly higher in MS patients compared to controls. However, normalization for total IgG content of paired serum and CSF samples abrogated this disease association. CONCLUSIONS: MS patients have normal overall anti-EBV antibody responses with increased reactivity to EBNA-1(394-451). No evidence was found for intrathecal EBNA-1-specific IgG synthesis in MS.

Neurofilament ELISA validation.

BACKGROUND: Neurofilament proteins (Nf) are highly specific biomarkers for neuronal death and axonal degeneration. As these markers become more widely used, an inter-laboratory validation study is required to identify assay criteria for high quality performance. METHODS: The UmanDiagnostics NF-light (R)enzyme-linked immunoabsorbent assays (ELISA) for the neurofilament light chain (NfL, 68kDa) was used to test the intra-assay and inter-laboratory coefficient of variation (CV) between 35 laboratories worldwide on 15 cerebrospinal fluid (CSF) samples. Critical factors, such as sample transport and storage, analytical delays, reaction temperature and time, the laboratories' accuracy and preparation of standards were documented and used for the statistical analyses. RESULTS: The intra-laboratory CV averaged 3.3% and the inter-laboratory CV 59%. The results from the test laboratories correlated with those from the reference laboratory (R=0.60, p<0.0001). Correcting for critical factors improved the strength of the correlation. Differences in the accuracy of standard preparation were identified as the most critical factor. Correcting for the error introduced by variation in the protein standards improved the correlation to R=0.98, p<0.0001 with an averaged inter-laboratory CV of 14%. The corrected overall inter-rater agreement was subtantial (0.6) according to Fleiss' multi-rater kappa and Gwet's AC1 statistics. CONCLUSION: This multi-center validation study identified the lack of preparation of accurate and consistent protein standards as the main reason for a poor inter-laboratory CV. This issue is also relevant to other protein biomarkers based on this type of assay and will need to be solved in order to achieve an acceptable level of analytical accuracy. The raw data of this study is available online.

Cigarette smoking and risk of MS in multiplex families.

Recent studies suggest that a history of cigarette smoking is a risk factor for multiple sclerosis (MS). We aimed to test the smoking effect in multiplex families, matching for both environmental and genetic factors. In a matched case-control study, 136 MS patients from 106 multiplex MS families were compared with their 204 healthy siblings as controls. Participants completed self-report questionnaires. Conditional logistic regression was used to analyse smoking and MS risk association while controlling for confounding by age and sex. Smoking history was classified in different variables. Within our survey the smoking history of MS patients and the controls did not differ. The odds of MS were comparable for different smoking levels. However, more intense exposure and women showed higher odds ratios, although non-significant. Association studies in families with relatively high genetic loading are unlikely to be confounded by smoking history.

Genetic variation in the KIF1B locus influences susceptibility to multiple sclerosis.

The few loci associated with multiple sclerosis (MS) are all related to immune function. We report a GWA study identifying a new locus replicated in 2,679 cases and 3,125 controls. An rs10492972[C] variant located in the KIF1B gene was associated with MS with an odds ratio of 1.35 (P = 2.5 x 10(-10)). KIF1B is a neuronally expressed gene plausibly implicated in the irreversible axonal loss characterizing MS in the long term.