Diffusion-Free Scaling in Rotating Spherical Rayleigh-Bénard Convection.

Direct numerical simulations are employed to reveal three distinctly different flow regions in rotating spherical Rayleigh-Bénard convection. In the high-latitude region I vertical (parallel to the axis of rotation) convective columns are generated between the hot inner and the cold outer sphere. The mid-latitude region I I is dominated by vertically aligned convective columns formed between the Northern and Southern hemispheres of the outer sphere. The diffusion-free scaling, which indicates bulk-dominated convection, originates from this mid-latitude region. In the equator region I I I , the vortices are affected by the outer spherical boundary and are much shorter than in region I I .

Clinical and virological findings in patients with Usutu virus infection, northern Italy, 2018.

BackgroundUsutu virus (USUV) is a mosquito-borne flavivirus, which shares its transmission cycle with the phylogenetically related West Nile virus (WNV). USUV circulates in several European countries and its activity has increased over the last 5 years.AimTo describe human cases of USUV infection identified by surveillance for WNV and USUV infection in the Veneto Region of northern Italy in 2018.MethodsFrom 1 June to 30 November 2018, all cases of suspected autochthonous arbovirus infection and blood donors who had a reactive WNV nucleic acid test were investigated for both WNV and USUV infection by in-house molecular methods. Anti-WNV and anti-USUV IgM and IgG antibodies were detected by ELISA and in-house immunofluorescence assay, respectively; positive serum samples were further tested by WNV and USUV neutralisation assays run in parallel.ResultsEight cases of USUV infection (one with neuroinvasive disease, six with fever and one viraemic blood donor who developed arthralgia and myalgia) and 427 cases of WNV infection were identified. A remarkable finding of this study was the persistence of USUV RNA in the blood and urine of three patients during follow-up. USUV genome sequences from two patients shared over 99% nt identity with USUV sequences detected in mosquito pools from the same area and clustered within lineage Europe 2.ConclusionsClinical presentation and laboratory findings in patients with USUV infection were similar to those found in patients with WNV infection. Cross-reactivity of serology and molecular tests challenged the differential diagnosis.

Long-term preclinical magnetic resonance imaging alterations in sporadic Creutzfeldt-Jakob disease.

An asymptomatic 74-year-old woman, on follow-up for a carotid body tumor, showed magnetic resonance imaging (MRI) focal restricted diffusion confined to the left temporal and occipital cortices. Thirteen months later, diffusion-weighted images revealed a bilateral cortical ribbon sign involving all lobes. After 1 month, the patient developed gait instability and cognitive decline rapidly evolving to severe dementia and death within 3 months. Prion protein gene sequence, molecular, and neuropathological studies confirmed the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) MM1 subtype. Here we show the kinetics of MRI changes and prion spreading in preclinical sCJD MM1. Ann Neurol 2016;80:629-632.

Posttraumatic dystonia and hemiplegic migraine: different expressions of neuronal hyperexcitability?

The development of focal hand dystonia after a traumatic injury of the central or the peripheral nervous system is a rare condition with multifactorial predisposing factors. We report on a patient who developed focal dystonia of the left hand after a cervical whiplash injury. Magnetic resonance imaging did not show cerebral or spinal lesions, whereas a brain F-FDG PET scan revealed hypometabolism of the right primary sensory-motor cortex extending to the inferior and superior parietal lobule. The patient had a history of recurrent migraine attacks. Four months before the whiplash injury, she had transient dystonic posture of the left hand during a hemiplegic migraine attack. Brain magnetic resonance imaging scan and neurovascular investigations were negative. Among the predisposing factors to the development of trauma-induced dystonia, a putative role of neuronal hyperexcitability, shared by migraine and dystonia, is discussed.

Parkinson-like features in ALS with predominant upper motor neuron involvement.

Owing to the frequent observation of poverty of movements, facial hypomimia and balance impairment, amyotrophic lateral sclerosis (ALS) variant with predominance of upper motor neuron involvement (UMN-ALS) is prone to be diagnosed with Parkinsonism. A clinical assessment, including the velocity-dependent stretch response test to differentiate between pyramidal and extrapyramidal stiffness; the Unified Parkinson's Disease Rating Scale and the Berg Balance Scale to assess degree of bradykinesia and postural instability; and (123)I-FP-CIT scintigraphy evaluation to investigate the nigrostriatal circuit involvement, were carried out to characterize Parkinson-like features in UMN-ALS patients. Sixteen UMN-ALS patients were included in the study. The velocity-dependent stretch response indicated spasticity in all the muscles tested. The degree of stiffness was found to be related to bradykinesia and postural instability. Eleven patients (70%) showed a reduction in striatal (123)I-FP-CIT uptake found to be related to disease duration and patients' ages but not to scores of the functional scales. Slowness of movements and postural instability noted in our patients could be mostly attributed to spasticity. The lack of any correlation between UPDRS or BBS scores and the degree of nigrostriatal impairment on DaTSCAN seems to disprove nigrostriatal circuit involvement in these extrapyramidal-like features.

Diffusion-weighted imaging does not predict histological grading in meningiomas.

PURPOSE: This study aims to verify the reliability of diffusion-weighted imaging (DWI) and apparent diffusion coefficient (ADC) measurements to differentiate benign from atypical/malignant meningiomas and among different sub-types. METHODS: Pre-operative DWI of 102 patients (74 females, mean age 58 years, age range 34-85 years) affected by a pathologically proven intracranial meningioma were retrospectively reviewed. DWI signal intensity of tumors was classified as hypo-, iso- or hyper-intense to grey matter. ADC values and normalised ADC(ratio) (ADC(meningioma)/ADC(normal appearing white matter)) of the neoplastic tissue (avoiding calcifications and cystic or necrotic areas) were measured by two neuroradiologists unaware of each others' reading. MRI and histological findings were compared. RESULTS: Meningiomas were histologically graded as malignant (1%), atypical (21.5%) and benign (77.5%). Meningothelial, transitional and fibrous were the most frequent benign sub-types (44, 16 and 10 cases, respectively). There was no statistical difference between typical and atypical/malignant meningiomas when considering mean ADC values (0.964 +/- 0.192 x 10(-3) vs 0.923 +/- 0.085 x 10(-3) cm(2)/s, p = 0.3 t-Student) or ADC(ratio) (1.266 +/- 0.290 vs 1.185 +/- 0.115, p = 0.2 t-Student). ADC values or ADC(ratio) did not differ significantly among meningioma sub-types although a nearly significant difference was found between meningothelial and transitional (post hoc analysis p = 0.06). Inter-observer agreement of ADC and ADC(ratio) measurements was high (r = 0.95 and 0.92, respectively, Pearson's linear coefficient). DWI intensity did not reach a significant correlation with meningioma's grading (p = 0.08). CONCLUSIONS: According to our study, DWI and ADC measurement do not seem reliable in grading meningiomas or identifying histological sub-types. Hence, these parameters should not be recommended for surgical or treatment planning.

Age-related changes in grey and white matter structure throughout adulthood.

Normal ageing is associated with gradual brain atrophy. Determining spatial and temporal patterns of change can help shed light on underlying mechanisms. Neuroimaging provides various measures of brain structure that can be used to assess such age-related change but studies to date have typically considered single imaging measures. Although there is consensus on the notion that brain structure deteriorates with age, evidence on the precise time course and spatial distribution of changes is mixed. We assessed grey matter (GM) and white matter (WM) structure in a group of 66 adults aged between 23 and 81. Multimodal imaging measures included voxel-based morphometry (VBM)-style analysis of GM and WM volume and diffusion tensor imaging (DTI) metrics of WM microstructure. We found widespread reductions in GM volume from middle age onwards but earlier reductions in GM were detected in frontal cortex. Widespread age-related deterioration in WM microstructure was detected from young adulthood onwards. WM decline was detected earlier and more sensitively using DTI-based measures of microstructure than using markers of WM volume derived from conventional T1-weighted imaging.

Wernicke's syndrome during parenteral feeding: not an unusual complication.

OBJECTIVE: Wernicke's encephalopathy (WE) is an acute disorder due to thiamine deficiency, characterized by ophthalmoplegia, ataxia, and mental confusion, similar to that classically observed in alcoholism. Some cases of WE were reported to coincide with other conditions such as hyperemesis gravidarum, bariatric surgery, and total parenteral nutrition. In this study the objective was to retrospectively evaluate the prevalence of WE among intravenously fed patients in our hospital during the previous 2 y. METHODS: Among all cases of WE diagnosed by cranial magnetic resonance scan during a 2-y period in the Azienda Ospedaliera of Padua, we identified patients who exhibited WE during parenteral feeding. Albumin plasma levels, measured at the onset of WE symptoms, were used to estimate nutritional status. RESULTS: We found seven cases of WE that coincided with intravenous feeding. WE occurred, on average, 13 d after the start of glucose infusion. The five subjects with albumin plasma levels lower than 35 g/L at the onset of WE received glucose infusion for fewer days. In six cases the clinical signs disappeared the day after thiamine infusion. In one case mental function did not normalize and the patient developed Korsakoff's syndrome despite prolonged thiamine treatment. CONCLUSION: During a 2-y period we observed a high prevalence of WE in intravenously fed patients due to lack of thiamine supplementation. A prophylactic treatment must be performed in at-risk patients and multivitamin infusion containing thiamine must be administered daily during the course of intravenous feeding.