Energetics of running in top-level marathon runners from Kenya

On ten top-level Kenyan marathon runners (KA) plus nine European controls (EC, equivalent to KA), we measured maximal oxygen consumption ( $$\dot{V}{\text{O}}_{{ 2 {\text{max}}}}$$ ) and the energy cost of running (C r) on track during training camps at moderate altitude, to better understand the KA dominance in the marathon. At each incremental running speed, steady-state oxygen consumption ( $$\dot{V}{\text{O}}_{ 2}$$ ) was measured by telemetric metabolic cart, and lactate by electro-enzymatic method. The speed requiring $$\dot{V}{\text{O}}_{ 2} = \dot{V}{\text{O}}_{{ 2 {\text{max}}}}$$ provided the maximal aerobic velocity (v max). The energy cost of running was calculated by dividing net $$\dot{V}{\text{O}}_{ 2}$$ by the corresponding speed. The speed at lactate threshold (v ΘAN) was computed from individual Lâb versus speed curves. The sustainable $$\dot{V}{\text{O}}_{{ 2 {\text{max}}}}$$ fraction (F d) at v ΘAN (F ΘAN) was computed dividing v ΘAN by v max. The F d for the marathon (F mar) was determined as F mar=0.92 F ΘAN. Overall, $$\dot{V}{\text{O}}_{{ 2 {\text{max}}}}$$ (64.9±5.8 vs. 63.9±3.7mlkg−1min−1), v max (5.55±0.30 vs. 5.41±0.29ms−1) and C r (3.64±0.28 vs. 3.63±0.31Jkg−1m−1) resulted the same in KA as in EC. In both groups, C r increased linearly with the square of speed. F ΘAN was 0.896±0.054 in KA and 0.909±0.068 in EC; F mar was 0.825±0.050 in KA and 0.836±0.062 in EC (NS). Accounting for altitude, running speed predictions from present data are close to actual running performances, if F ΘAN instead of F mar is taken as index of F d. In conclusion, both KA and EC did not have a very high $$\dot{V}{\text{O}}_{{ 2 {\text{max}}}}$$ , but had extremely high F d, and low C r, equal between them. The dominance of KA over EC cannot be explained on energetic ground

Congenital mirror movements in a new Italian family

Mirror movements (MMs) occur on the contralateral side of a limb being used intentionally. Because few families with congenital MMs and no other neurological signs have been reported, the underlying mechanisms of MMs are still not entirely clear. We report on the clinical, genetic, neurophysiological and neuroimaging findings of 10 of 26 living members of a novel four-generation family with congenital MMs. DCC and RAD51 were sequenced in affected members of the family. Five of the ten subjects with MMs underwent neurophysiological and neuroimaging evaluations. The neurophysiological evaluation consisted of electromyographic (EMG) mirror recordings, investigations of corticospinal excitability, and analysis of interhemispheric inhibition using transcranial magnetic stimulation techniques. The neuroimaging evaluation included functional MRI during finger movements. Eight (all females) of the ten members examined presented MMs of varying degrees at the clinical assessment. Transmission of MMs appears to have occurred according to an autosomal-dominant fashion with variable expression. No mutation in DCC or RAD51 was identified. EMG mirror activity was higher in MM subjects than in healthy controls. Short-latency interhemispheric inhibition was reduced in MM subjects. Ipsilateral motor-evoked potentials were detectable in the most severe case. The neuroimaging evaluation did not disclose any significant abnormalities in MM subjects. The variability of the clinical features of this family, and the lack of known genetic abnormalities, suggests that MMs are heterogeneous disorders. The pathophysiological mechanisms of MMs include abnormalities of transcallosal inhibition and corticospinal decussatio

PTPA variants and impaired PP2A activity in early-onset parkinsonism with intellectual disability

The protein phosphatase 2A complex (PP2A), the major Ser/Thr phosphatase in the brain, is involved in a number of signalling pathways and functions, including the regulation of crucial proteins for neurodegeneration, such as alpha-synuclein, tau and LRRK2. Here, we report the identification of variants in the PTPA/PPP2R4 gene, encoding a major PP2A activator, in two families with early-onset parkinsonism and intellectual disability. We carried out clinical studies and genetic analyses, including genome-wide linkage analysis, whole-exome sequencing, and Sanger sequencing of candidate variants. We next performed functional studies on the disease-associated variants in cultured cells and knock-down of ptpa in Drosophila melanogaster. We first identified a homozygous PTPA variant, c.893T&gt;G (p.Met298Arg), in patients from a South African family with early-onset parkinsonism and intellectual disability. Screening of a large series of additional families yielded a second homozygous variant, c.512C&gt;A (p.Ala171Asp), in a Libyan family with a similar phenotype. Both variants co-segregate with disease in the respective families. The affected subjects display juvenile-onset parkinsonism and intellectual disability. The motor symptoms were responsive to treatment with levodopa and deep brain stimulation of the subthalamic nucleus. In overexpression studies, both the PTPA p.Ala171Asp and p.Met298Arg variants were associated with decreased PTPA RNA stability and decreased PTPA protein levels; the p.Ala171Asp variant additionally displayed decreased PTPA protein stability. Crucially, expression of both variants was associated with decreased PP2A complex levels and impaired PP2A phosphatase activation. PTPA orthologue knock-down in Drosophila neurons induced a significant impairment of locomotion in the climbing test. This defect was age-dependent and fully reversed by L-DOPA treatment. We conclude that bi-allelic missense PTPA variants associated with impaired activation of the PP2A phosphatase cause autosomal recessive early-onset parkinsonism with intellectual disability. Our findings might also provide new insights for understanding the role of the PP2A complex in the pathogenesis of more common forms of neurodegeneration.</p

Gray and white matter structural changes in corticobasal syndrome

We investigated gray matter and white matter (WM) changes in corticobasal syndrome (CBS). T1-weighted and diffusion tensor images (3T-magnet) were obtained in 11 patients and 11 healthy subjects (HS). Magnetic resonance imaging data were analyzed using FreeSurfer and Tracts Constrained by Underlying Anatomy to evaluate cortical thickness (CTh), surface area, and subcortical volumes as well as diffusion tensor image parameters along the major WM tracts. Compared with HS, the whole patient group showed decreased CTh in the prefrontal cortex, precentral gyrus, supplementary motor area, insula, and temporal pole bilaterally. When we divided patients into 2 subgroups (left: L-CBS, right: R-CBS) on the basis of the clinically more affected upper limb, the most prominent decrease in CTh occurred in the hemisphere contralateral to the more affected side. The whole patient group also had volume loss in the putamen, hippocampus, and accumbens bilaterally, in the corpus callosum and right amygdala. Finally, we found diffusion changes in several WM tracts with axial diffusivity being altered more than radial diffusivity. The upper limb motor severity negatively correlated with the contralateral CTh in the precentral and/or postcentral gyri and contralateral volumes of putamen and accumbens. The CTh asymmetry in postcentral and/or paracentral gyri also negatively correlated with disease duration. Cortical thinning, volume loss, and fiber tract degeneration in specific brain regions are important pathophysiological abnormalities in CB

Freezing of gait in parkinson's disease. gray and white matter abnormalities

Freezing of gait (FOG) is a disabling disor- der that often a ects Parkinson’s disease (PD) patients in advanced stages of the disease. To study structural gray mat- ter (GM) and white matter (WM) changes in PD patients with and without FOG, twenty-one PD patients with FOG (PD-FOG), 16 PD patients without FOG (PD-nFOG) and 19 healthy subjects (HS) underwent a standardized MRI protocol. For the gray matter evaluation, cortical volume (CV), cortical thickness (CTh), and surface area (SA) were analyzed using the FreeSurfer pipeline. For the white mat- ter evaluation, DTI images were analyzed using tracts con- strained by underlying anatomy (TRACULA) toolbox in FreeSurfer. PD-FOG patients exhibited lower CTh than HS in the mesial surface of both cerebral hemispheres, includ- ing the superior frontal gyrus, paracentral lobule, posterior cingulate cortex, precuneus and pericalcarine cortex, and in the right dorsolateral prefrontal cortex. Moreover, sig- ni cant WM changes were observed in PD-FOG patients in comparison with HS in the superior longitudinal fasciculus, uncinate fasciculus, cingulum cingulate gyrus and inferior longitudinal fasciculus (prevalently in the right hemisphere) and in the frontal radiations of the corpus callosum. DTI abnormalities in speci c WM bundles correlated signi - cantly with cognitive measures. The damage of multiple cortical areas involved in high-level gait control together with WM disruption between motor, cognitive and limbic structures may represent the anatomical correlate of FOG

Epileptic seizures heralding a relapse in high grade gliomas

Abstract PURPOSE: Seizures are a common clinical symptom in high-grade gliomas (HGG). The aim of the study was to investigate the relationship between seizures and HGG relapse (HGG-R). METHODS: We retrospectively evaluated 145 patients who were surgically treated for HGG-R. By analyzing clinical characteristics in these patients (all operated and treated by the same protocol), we identified 37 patients with seizures during follow-up. This cohort was divided into four subgroups according to a) presence or absence of seizures at the time of diagnosis and b) temporal relationship between seizure occurrence and HGG-R during follow-up: subgroup A (25pts) had seizures at follow-up but not at onset, subgroup B (12pts) had seizures both at follow-up and onset, subgroup C (30pts) had seizures before MRI-documented HGG-R, and subgroup D (7pts) had seizures after MRI-documented HGG-R. RESULTS: Although the datum was not statistically significant, survival was longer in patients with seizures during follow-up than in those without seizures (59.3% vs 51.4% alive at 2 years). In 30 patients (subgroup C) seizures heralded HGG-R. In a correlation analysis for this last subgroup, the time interval between seizure and the HGG-R was significantly associated with the number of chemotherapy cycles (r=0.470; p=0.009) and follow-up duration (r=0.566; p=0.001). A linear regression model demonstrated a reciprocal association between the above factors and that it may be possible to estimate the timing of HGG-R by combining these data. CONCLUSIONS: Seizures may herald HGG-R before MRI detection of relapse, thus suggesting that seizures should always be considered a red flag during follow-up

Risk factors of Parkinson\u2019s disease: simultaneous assessment, interactions and etiological subtypes

Objective: To perform a simultaneous evaluation of potential risk/protective factors of Parkinson's disease (PD) in order to identify independent risk/protective factors, assess interaction among factors and determine whether identified risk factors predict etiological subtypes of PD. Methods: We designed a large case-control study assessing 31 protective/risk factors of PD, including environmental and lifestyle factors, comorbidities, and drugs. The study enrolled 694 PD patients and 640 healthy controls from six neurological centers. Data were analyzed by logistic regression models, additive interaction models, and cluster analysis. Results: The simultaneous assessment of 31 putative risk/protective factors of PD showed that only coffee consumption (odds ratio [OR]: 0.6; 95% confidence interval [CI]: 0.4-0.9), smoking (OR: 0.7; 95% CI: 0.6-0.9), physical activity (OR: 0.8; 95% CI: 0.7-0.9), family history of PD (OR: 3.2; 95% CI: 2.2- 4.8), dyspepsia (OR: 1.8; 95% CI:1.3-2.4), exposure to pesticides (OR: 2.3; 95% CI:1.3- 4.2), oils (OR: 5.6; 95% CI: 2.3-13.7), metals (OR: 2.8; 95% CI: 1.5-5.4), and general anesthesia (OR: 6.1; 95% CI: 2.9-12.7) were independently associated with PD. There was no evidence of interaction among risk/protective factors, but cluster analysis identified four subtypes with different risk factor profiles. In Group 1, all patients had a family history of PD, while dyspepsia or exposure to toxic agents were present in 30% of patients. In Group 2 and 3, a family history of PD was lacking, while exposure to toxic agents (Group 2) and dyspepsia (Group 3) played major roles. Group 4 consisted of patients with no risk factors. Conclusions: This study demonstrated that nine factors independently modify PD risk by coexisting in the same patient rather than interacting with others. Our study suggests the need for future preventive strategies aimed at reducing the coexistence of different risk factors within the same subject

Expert recommendations for diagnosing cervical, oromandibular, and limb dystonia

Background: Diagnosis of focal dystonia is based on clinical grounds and is therefore open to bias. To date, diagnostic guidelines have been only proposed for blepharospasm and laryngeal dystonia. To provide practical guidance for clinicians with less expertise in dystonia, a group of Italian Movement Disorder experts formulated clinical diagnostic recommendations for cervical, oromandibular, and limb dystonia. Methods: A panel of four neurologists generated a list of clinical items related to the motor phenomenology of the examined focal dystonias and a list of clinical features characterizing neurological/non-neurological conditions mimicking dystonia. Thereafter, ten additional expert neurologists assessed the diagnostic relevance of the selected features and the content validity ratio was calculated. The clinical features reaching a content validity ratio > 0.5 contributed to the final recommendations. Results: The recommendations retained patterned and repetitive movements/postures as the core feature of dystonia in different body parts. If present, a sensory trick confirmed diagnosis of dystonia. In the patients who did not manifest sensory trick, active exclusion of clinical features related to conditions mimicking dystonia (features that would be expected to be absent in dystonia) would be necessary for dystonia to be diagnosed. Discussion: Although reliability, sensitivity, and specificity of the recommendations are yet to be demonstrated, information from the present study would hopefully facilitate diagnostic approach to focal dystonias in the clinical practice and would be the basis for future validated diagnostic guidelines