Maf/ham1-like pyrophosphatases of non-canonical nucleotides are host-specific partners of viral RNA-dependent RNA polymerases.

Cassava brown streak disease (CBSD), dubbed the "Ebola of plants", is a serious threat to food security in Africa caused by two viruses of the family Potyviridae: cassava brown streak virus (CBSV) and Ugandan (U)CBSV. Intriguingly, U/CBSV, along with another member of this family and one secoviridae, are the only known RNA viruses encoding a protein of the Maf/ham1-like family, a group of widespread pyrophosphatase of non-canonical nucleotides (ITPase) expressed by all living organisms. Despite the socio-economic impact of CDSD, the relevance and role of this atypical viral factor has not been yet established. Here, using an infectious cDNA clone and reverse genetics, we demonstrate that UCBSV requires the ITPase activity for infectivity in cassava, but not in the model plant Nicotiana benthamiana. HPLC-MS/MS experiments showed that, quite likely, this host-specific constraint is due to an unexpected high concentration of non-canonical nucleotides in cassava. Finally, protein analyses and experimental evolution of mutant viruses indicated that keeping a fraction of the yielded UCBSV ITPase covalently bound to the viral RNA-dependent RNA polymerase (RdRP) optimizes viral fitness, and this seems to be a feature shared by the other members of the Potyviridae family expressing Maf/ham1-like proteins. All in all, our work (i) reveals that the over-accumulation of non-canonical nucleotides in the host might have a key role in antiviral defense, and (ii) provides the first example of an RdRP-ITPase partnership, reinforcing the idea that RNA viruses are incredibly versatile at adaptation to different host setups.

[An open study evaluating the efficacy and security of magnesium and vitamin B(6) as a treatment of Tourette syndrome in children]. / Estudio piloto sin grupo control del tratamiento con magnesio y vitamina B(6) del síndrome de Gilles de la Tourette en niños.

BACKGROUND AND OBJECTIVE: We intended to ascertain the effectiveness and safety of oral solutions of magnesium and vitamin B(6) in alleviating the symptoms emerged during clinical exacerbations in children aged 7-14 years suffering from Tourette syndrome (TS). We also aimed to determine the mean and the standard deviation of such an improvement in order to estimate sample sizes in future assays with a control group. PATIENTS AND METHOD: The treatment under investigation was administered to children diagnosed with TS, in accordance with Diagnostic and Statistical Manual of Mental Disorders, fourth edition -IV, under conditions of clinical exacerbation. The effects were scored on the Yale Global Tics Severity Scale (YGTSS) at 0, 15, 30, 60 and 90 days. RESULTS: The total tics score decreased from 26.7 (t0) to 12.9 (t4) and the total effect on the YGTSS was a reduction from 58.1 to 18.8. Both results were statistically significant. With respect to the application of conventional treatment or otherwise, no significant differences were observed. No side effects were seen. CONCLUSIONS: The treatment assayed is safe and effective in reducing the harmful effects of TS in children. Further studies are needed, with a control group, and evaluation of different doses of the drugs.

New therapeutic approach to Tourette Syndrome in children based on a randomized placebo-controlled double-blind phase IV study of the effectiveness and safety of magnesium and vitamin B6.

BACKGROUND: Tourette Syndrome (TS) is a neurological condition presenting chronic motor and phonic tics, and important degree of comorbidity. Considered an uncommon illness, it first becomes apparent during childhood. Current standard treatment only achieves partial control of the condition, and provokes frequent, and sometimes severe, side effects. METHODS AND DESIGN: Main aim: To show that, with respect to placebo treatment, the combination of 0.5 mEq/Kg magnesium and 2 mg/Kg vitamin B6 reduces motor and phonic tics and incapacity in cases of exacerbated TS among children aged 7-14 years, as measured on the Yale Global Tic Severity Scale (YGTSS). Secondary aims: Assess the safety of the treatment. Describe metabolic changes revealed by PET. Measure the impact of the experimental treatment on family life. METHODOLOGY: Randomized, blinded clinical trials. Phase IV study (new proposal for treatment with magnesium and vitamin B6). SCOPE: children in the geographic area of the study group. Recruitment of subjects: to include patients diagnosed with TS, in accordance with DSM-IV criteria (307.23), during a period of exacerbation, and provided none of the exclusion criteria are met. INSTRUMENTATION: clinical data and the YGTSS score will be obtained at the outset of a period of exacerbation (t0). The examinations will be made after 15 (t1), 30 (t2), 60 (t3) and 90 days (t4). PET will be performed at the t0 and t4. We evaluated decrease in the overall score (t0, t1, t2, t3, t4), PET variations, and impact made by the treatment on the patient's life (Psychological General Well-Being Index). DISCUSSION: Few clinical trials have been carried out on children with TS, but they are necessary, as current treatment possibilities are insufficient and often provoke side effects. The difficulty of dealing with an uncommon illness makes designing such a study all the more complicated. The present study seeks to overcome possible methodological problems by implementing a prior, phase II study, in order to calculate the relevant statistical parameters and to determine the safety of the proposed treatment. Providing a collateral treatment with magnesium and vitamin B6 could improve control of the illness and help reduce side effects. This protocol was approved by the Andalusian Government Committee for Clinical Trials (Spain). This study was funded by the Health Department of the Andalusian Regional Government and by the Healthcare Research Fund of the Carlos III Healthcare Institute (Spanish Ministry of Health). TRIAL REGISTRATION: Current Controlled Trials ISRCTN41082378.