Guillain-Barré syndrome: advances and future perspectives

The first case of Guillain-Barré syndrome was described in 1916. Since then, knowledge about the pathophysiology and immunogenesis of this acquired inflammatory polyradiculoneuropathy has been growing steadily, especially after the advent of nerve conduction studies and the discovery of pathogenic autoantibodies. In the present study, we conducted a review of the main information available in the literature to date about the syndrome, including its diagnosis and management

StaR Is a Positive Regulator of Topoisomerase I Activity Involved in Supercoiling Maintenance in Streptococcus pneumoniae

The DNA topoisomerases gyrase and topoisomerase I as well as the nucleoid-associated protein HU maintain supercoiling levels in Streptococcus pneumoniae, a main human pathogen. Here, we characterized, for the first time, a topoisomerase I regulator protein (StaR). In the presence of sub-inhibitory novobiocin concentrations, which inhibit gyrase activity, higher doubling times were observed in a strain lacking staR, and in two strains in which StaR was over-expressed either under the control of the ZnSO4-inducible PZn promoter (strain ΔstaRPZnstaR) or of the maltose-inducible PMal promoter (strain ΔstaRpLS1ROMstaR). These results suggest that StaR has a direct role in novobiocin susceptibility and that the StaR level needs to be maintained within a narrow range. Treatment of ΔstaRPZnstaR with inhibitory novobiocin concentrations resulted in a change of the negative DNA supercoiling density (σ) in vivo, which was higher in the absence of StaR (σ = -0.049) than when StaR was overproduced (σ = -0.045). We have located this protein in the nucleoid by using super-resolution confocal microscopy. Through in vitro activity assays, we demonstrated that StaR stimulates TopoI relaxation activity, while it has no effect on gyrase activity. Interaction between TopoI and StaR was detected both in vitro and in vivo by co-immunoprecipitation. No alteration of the transcriptome was associated with StaR amount variation. The results suggest that StaR is a new streptococcal nucleoid-associated protein that activates topoisomerase I activity by direct protein-protein interaction.This research and the APC were funded by project PID2021-124738OB-100 to A.G.d.l.C., financed by MCIN/AEI/10.13039/501100011033/FEDER, UE.S

Association between Knops blood group polymorphisms and susceptibility to malaria in an endemic area of the Brazilian Amazon

Complement receptor 1 (CR1) gene polymorphisms that are associated with Knops blood group antigens may influence the binding of Plasmodium parasites to erythrocytes, thereby affecting susceptibility to malaria. The aim of this study was to evaluate the genotype and allele and haplotype frequencies of single-nucleotide polymorphisms (SNPs) of Knops blood group antigens and examine their association with susceptibility to malaria in an endemic area of Brazil. One hundred and twenty-six individuals from the Brazilian Amazon were studied. The CR1-genomic fragment was amplified by PCR and six SNPs and haplotypes were identified after DNA sequence analysis. Allele and haplotype frequencies revealed that the Knb allele and H8 haplotype were possibly associated with susceptibility to Plasmodium falciparum. The odds ratios were reasonably high, suggesting a potentially important association between two Knops blood antigens (Knb and KAM+) that confer susceptibility to P. falciparum in individuals from the Brazilian Amazon

Neurological Impacts of Covid-19 and Worldwide Scientific Production about the Subject: A Bibliometric Analysis

Introduction: The novel Coronavirus (COVID-19) was first reported by officials in Wuhan City, in December 2019. It has rapidly spread with confirmed cases in almost every country across the world and has caused a global public health crisis.¹ The epidemiological update of the World Health Organization on9th March 2021 showed that over 2.7 million new cases were reported. In this article, a biblometrical analysis of trending topics and what is being researched regarding COVID-19 and its neurological involvement is done. Methods: This research was conducted on the Web of Science Core Collection (WoS). For research in WoS, keywords in English were used, according to DeCS - Descriptors in Health Sciences. The search strategy with Boolean operators was: TS = (SARS-CoV-2 OR COVID-19) AND TS=(Neurologic Findings OR Neurology OR Neurologic Manifestations). Results: In total, 392 scientific productions were identified and included in this bibliometric analysis. The studies were publishedin the period between March 2020 and March 2021, with records prevalent in the themes of clinical neurology (n=234) and neurosciences (n=134), as well as several other areas. The thirty studies collected a total of 3395 citations, with variations from 1433 to 26 and average of 113 citations per study. All werepublished in 2020, with bigger prevalence in July (nine articles) and June (six articles). Conclusion: It is expected that this bibliometric survey will serve as a manner of presenting the main topics of study within neurology before COVID-19, in addition providing guidance for future research.

Estimate of Leaf Area Index in an Old-Growth Mixed Broadleaved-Korean Pine Forest in Northeastern China

Leaf area index (LAI) is an important variable in the study of forest ecosystem processes, but very few studies are designed to monitor LAI and the seasonal variability in a mixed forest using non-destructive sampling. In this study, first, true LAI from May 1st and November 15th was estimated by making several calibrations to LAI as measured from the WinSCANOPY 2006 Plant Canopy Analyzer. These calibrations include a foliage element (shoot, that is considered to be a collection of needles) clumping index measured directly from the optical instrument, TRAC (Tracing Radiation and Architecture of Canopies); a needle-to-shoot area ratio obtained from shoot samples; and a woody-to-total area ratio. Second, by periodically combining true LAI (May 1st) with the seasonality of LAI for deciduous and coniferous species throughout the leaf-expansion season (from May to August), we estimated LAI of each investigation period in the leaf-expansion season. Third, by combining true LAI (November 15th) with litter trap data (both deciduous and coniferous species), we estimated LAI of each investigation period during the leaf-fall season (from September to mid-November). Finally, LAI for the entire canopy then was derived from the initial leaf expansion to the leaf fall. The results showed that LAI reached its peak with a value of 6.53 m2 m−2 (a corresponding value of 3.83 m2 m−2 from optical instrument) in early August, and the mean LAI was 4.97 m2 m−2 from May to November using the proposed method. The optical instrument method underestimated LAI by an average of 41.64% (SD = 6.54) throughout the whole study period compared to that estimated by the proposed method. The result of the present work implied that our method would be suitable for measuring LAI, for detecting the seasonality of LAI in a mixed forest, and for measuring LAI seasonality for each species