Adaptive filtering methods for identifying cross-frequency couplings in human EEG.

Oscillations have been increasingly recognized as a core property of neural responses that contribute to spontaneous, induced, and evoked activities within and between individual neurons and neural ensembles. They are considered as a prominent mechanism for information processing within and communication between brain areas. More recently, it has been proposed that interactions between periodic components at different frequencies, known as cross-frequency couplings, may support the integration of neuronal oscillations at different temporal and spatial scales. The present study details methods based on an adaptive frequency tracking approach that improve the quantification and statistical analysis of oscillatory components and cross-frequency couplings. This approach allows for time-varying instantaneous frequency, which is particularly important when measuring phase interactions between components. We compared this adaptive approach to traditional band-pass filters in their measurement of phase-amplitude and phase-phase cross-frequency couplings. Evaluations were performed with synthetic signals and EEG data recorded from healthy humans performing an illusory contour discrimination task. First, the synthetic signals in conjunction with Monte Carlo simulations highlighted two desirable features of the proposed algorithm vs. classical filter-bank approaches: resilience to broad-band noise and oscillatory interference. Second, the analyses with real EEG signals revealed statistically more robust effects (i.e. improved sensitivity) when using an adaptive frequency tracking framework, particularly when identifying phase-amplitude couplings. This was further confirmed after generating surrogate signals from the real EEG data. Adaptive frequency tracking appears to improve the measurements of cross-frequency couplings through precise extraction of neuronal oscillations.

The Swiss Systemic lupus erythematosus Cohort Study (SSCS) - cross-sectional analysis of clinical characteristics and treatments across different medical disciplines in Switzerland.

OBJECTIVES: To describe disease characteristics and treatment modalities in a multidisciplinary cohort of systemic lupus erythematosus (SLE) patients in Switzerland. METHODS: Cross-sectional analysis of 255 patients included in the Swiss SLE Cohort and coming from centres specialised in Clinical Immunology, Internal Medicine, Nephrology and Rheumatology. Clinical data were collected with a standardised form. Disease activity was assessed using the Safety of Estrogens in Lupus Erythematosus National Assessment-SLE Disease Activity Index (SELENA-SLEDAI), an integer physician's global assessment score (PGA) ranging from 0 (inactive) to 3 (very active disease) and the erythrocyte sedimentation rate (ESR). The relationship between SLE treatment and activity was assessed by propensity score methods using a mixed-effect logistic regression with a random effect on the contributing centre. RESULTS: Of the 255 patients, 82% were women and 82% were of European ancestry. The mean age at enrolment was 44.8 years and the median SLE duration was 5.2 years. Patients from Rheumatology had a significantly later disease onset. Renal disease was reported in 44% of patients. PGA showed active disease in 49% of patients, median SLEDAI was 4 and median ESR was 14 millimetre/first hour. Prescription rates of anti-malarial drugs ranged from 3% by nephrologists to 76% by rheumatologists. Patients regularly using anti-malarial drugs had significantly lower SELENA-SLEDAI scores and ESR values. CONCLUSION: In our cohort, patients in Rheumatology had a significantly later SLE onset than those in Nephrology. Anti-malarial drugs were mostly prescribed by rheumatologists and internists and less frequently by nephrologists, and appeared to be associated with less active SLE.

CTL activation is induced by cross-linking of TCR/MHC-peptide-CD8/p56lck adducts in rafts.

To investigate the role of the coreceptor CD8 and lipid rafts in cytotoxic T lymphocyte (CTL) activation, we used soluble mono-and multimeric H-2Kd-peptide complexes and cloned S14 CTL specific for a photoreactive derivative of the Plasmodium berghei circumsporozoite (PbCS) peptide 252-260 [PbCS(ABA)]. We report that activation of CTL in suspension requires multimeric Kd-PbCS(ABA) complexes co-engaging TCR and CD8. Using TCR ligand photo-cross-linking, we find that monomeric Kd-PbCS(ABA) complexes promote association of TCR/CD3 with CD8/p56lck. Dimerization of these adducts results in activation of p56lck in lipid rafts, where phosphatases are excluded. Additional cross-linking further increases p56lck kinase activity, induces translocation of TCR/CD3 and other signaling molecules to lipid rafts and intracellular calcium mobilization. These events are prevented by blocking Src kinases or CD8 binding to TCR-associated Kd molecules, indicating that CTL activation is initiated by cross-linking of CD8-associated p56lck. They are also inhibited by methyl-beta-cyclodextrin, which disrupts rafts and by dipalmitoyl phosphatidylethanolamine, which interferes with TCR signaling. Because efficient association of CD8 and p56lck takes place in rafts, both reagents, though in different ways, impair coupling of p56lck to TCR, thereby inhibiting the initial and essential activation of p56lck induced by cross-linking of engaged TCR.

Enterobiasis and strongyloidiasis and associated co-infections and morbidity markers in infants, preschool- and school-aged children from rural coastal Tanzania: a cross-sectional study.

Background. There is a paucity of data pertaining to the epidemiology and public health impact of Enterobius vermicularis and Strongyloides stercoralis infections. We aimed to determine the extent of enterobiasis, strongyloidiasis, and other helminth infections and their association with asymptomatic Plasmodium parasitaemia, anaemia, nutritional status, and blood cell counts in infants, preschool-aged (PSAC), and school-aged children (SAC) from rural coastal Tanzania.MethodsA total of 1,033 children were included in a cross-sectional study implemented in the Bagamoyo district in 2011/2012. Faecal samples were examined for intestinal helminth infections using a broad set of quality controlled methods. Finger-prick blood samples were subjected to filariasis and Plasmodium parasitaemia testing and full blood cell count examination. Weight, length/height, and/or mid-upper arm circumference were measured and the nutritional status determined in accordance with age.Results E. vermicularis infections were found in 4.2% of infants, 16.7%, of PSAC, and 26.3% of SAC. S. stercoralis infections were detected in 5.8%, 7.5%, and 7.1% of infants, PSAC, and SAC, respectively. Multivariable regression analyses revealed higher odds of enterobiasis in children of all age-groups with a reported anthelminthic treatment history over the past six months (odds ratio (OR): 2.15; 95% confidence interval (CI): 1.22 - 3.79) and in SAC with a higher temperature (OR: 2.21; CI: 1.13 - 4.33). Strongyloidiasis was associated with eosinophilia (OR: 2.04; CI: 1.20-3.48) and with Trichuris trichiura infections (OR: 4.13; CI: 1.04-16.52) in children of all age-groups, and with asymptomatic Plasmodium parasitaemia (OR: 13.03; CI: 1.34 - 127.23) in infants. None of the investigated helminthiases impacted significantly on the nutritional status and anaemia, but moderate asymptomatic Plasmodium parasitaemia was a strong predictor for anaemia in children aged older than two years (OR: 2.69; 95% CI: 1.23 ¿ 5.86).Conclusions E. vermicularis and S. stercoralis infections were moderately prevalent in children from rural coastal Tanzania. Our data can contribute to inform yet missing global burden of disease and prevalence estimates for strongyloidiasis and enterobiasis. The association between S stercoralis and asymptomatic Plasmodium parasitaemia found here warrants further comprehensive investigations.

Serological cross-reactivity between different Chlamydia-like organisms.

The serological cross-reactivity between different recently described Chlamydia-related organisms was determined. Mouse sera exhibited a strong reactivity against autologous antigen and closely related heterologous antigen but no cross-reactivity with distantly related species. These results are important to better interpret serological studies and assess the pathogenic role of these obligate intracellular bacteria.

The relationship between muscle strength and physiological age: a cross-sectional study in boys aged from 11 to 15.

OBJECTIVE: To investigate the relationships between isokinetic knee flexor and extensor muscle strength and physiological and chronological age in young soccer players. MATERIAL AND METHODS: Seventy-nine young, healthy, male soccer players (mean+/-standard deviation age: 12.78+/-2.88, range: 11 to 15) underwent a clinical examination (age, weight, height, body mass index and Tanner puberty stage) and an evaluation of bilateral knee flexor and extensor muscle strength on an isokinetic dynamometer. Participation in the study was voluntary. RESULTS: The peak torque increased progressively (by 50%) between the ages of 11 and 15 and most significantly between 12 to 14. The knee flexor/extensor ratios only decreased significantly between 14 and 15 years of age. Puberty stage was the most important determinant of the peak torque level (ahead of chronological age, weight and height) for all angular velocities (p<0.0001). Muscle strength increased significantly between Tanner stages 1 and 5, with the greatest increase between stages 2 and 4. CONCLUSION: The present study showed that isokinetic muscle strength increases most between 12 and 13 years of age and between Tanner stages 2 and 3. There was strong correlation between muscle strength and physiological age.