Transcranial sonography in dopa-responsive dystonia.

BACKGROUND AND PURPOSE: Mutations in the GCH1 gene, encoding GTP cyclohydrolase 1, the enzyme critically important for dopamine production in nigrostriatal neurons, are the most common cause of dopa-responsive dystonia (DRD), characterized predominantly by limb dystonia, although parkinsonian features may also be present. It has been suggested that DRD is a neurochemical rather than neurodegenerative disorder. METHODS: Transcranial brain sonography, which might be a risk marker for nigral injury, was obtained from 141 subjects divided into four groups: (i) 11 patients with genetically confirmed DRD; (ii) 55 consecutive patients with Parkinson's disease (PD); (iii) 30 patients diagnosed as isolated adult-onset focal dystonia; and (iv) 45 healthy controls (HCs). RESULTS: Substantia nigra hyperechogenicity was present in 63.6% of patients with DRD, which was significantly different in comparison to patients with dystonia (20%) and HCs (6.7%), but not in comparison to the PD group (87.3%). Also, values of the maximal areas of substantia nigra hyperechogenicity in patients with DRD were higher in comparison to HCs, but significantly lower than among the PD group. CONCLUSIONS: We suggested that the observed transcranial brain sonography features in patients with DRD might primarily be risk markers for particular clinical features (parkinsonism, dystonia) occurring in the specific genetic context (i.e. GCH1 mutations), or might reflect compensated neurodegenerative processes triggered by the long-lasting dopamine deficiency due to the profound delay in levodopa treatment in our patients with DRD.

Molecular-level understanding of the adsorption mechanism of a graphite-binding peptide at the water/graphite interface.

The association of proteins and peptides with inorganic material has vast technological potential. An understanding of the adsorption of peptides at liquid/solid interfaces on a molecular-level is fundamental to fully realising this potential. Combining our prior work along with the statistical analysis of 100+ molecular dynamics simulations of adsorption of an experimentally identified graphite binding peptide, GrBP5, at the water/graphite interface has been used here to propose a model for the adsorption of a peptide at a liquid/solid interface. This bottom-up model splits the adsorption process into three reversible phases: biased diffusion, anchoring and lockdown. Statistical analysis highlighted the distinct roles played by regions of the peptide studied here throughout the adsorption process: the hydrophobic domain plays a significant role in the biased diffusion and anchoring phases suggesting that the initial impetus for association between the peptide and the interface may be hydrophobic in origin; aromatic residues dominate the interaction between the peptide and the surface in the adsorbed state and the polar region in the middle of the peptide affords a high conformational flexibility allowing strongly interacting residues to maximise favourable interactions with the surface. Reversible adsorption was observed here, unlike in our prior work focused on a more strongly interacting surface. However, this reversibility is unlikely to be seen once the peptide-surface interaction exceeds 10 kcal mol(-1).

Clinical consequences of aspirin and clopidogrel resistance: an overview.

The aim of this review is to introduce the concept of personalized medicine in secondary stroke prevention with antiplatelet medication. In the last years, many studies have been conducted regarding aspirin resistance and genotyping of clopidogrel metabolism. A review of the currently published data on this issue emphasizes the importance of focusing on the individualizing approach in antiplatelet therapy to achieve maximal therapeutic beneficial effect. However, many authors suggest that, before new information from ongoing trials become available, good clinical practice should dictate the use of low dose of aspirin that was shown to be effective in the prevention of stroke and death in patients with ischemic cerebrovascular disease, because higher doses do not have significantly better efficacy than lower doses in secondary stroke prevention, but lower-dose aspirin is associated with less side effects. On the other hand, many factors are associated with clopidogrel resistance, and recent genetic studies showed that the CYP2C19*2 genotype (loss-of-function allele) is related to poor metabolism of clopidogrel, but larger studies are needed to definitively confirm or rule out the clinical significance of this genetic effect. The aim of personalized approach in secondary stroke prevention is to take the most appropriate medicine in the right dose in accordance with the clinical condition of the patient and associated risk factors.

Microfluidic hydrodynamic focusing based synthesis of POPC liposomes for model biological systems.

Lipid vesicles have received significant attention in areas ranging from pharmaceutical and biomedical engineering to novel materials and nanotechnology. Microfluidic-based synthesis of liposomes offers a number of advantages over the more traditional synthesis methods such as extrusion and sonication. One such microfluidic approach is microfluidic hydrodynamic focusing (MHF), which has been used to synthesize nanoparticles and vesicles of various lipids. We show here that this method can be utilized in synthesis of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) vesicles with controllable size. Since POPC is among the primary constituents of cellular membranes, this work is of direct applicability to modelling of biological systems and development of nano-containers with higher biologic compatibility for pharmaceutical and medical applications.

Transcranial brain sonography findings in two main variants of progressive supranuclear palsy.

BACKGROUND AND PURPOSE: Progressive supranuclear palsy (PSP) can occur with two main clinical presentations, classified as classical Richardson's syndrome (PSP-RS) and as PSP-parkinsonism (PSP-P), the most common atypical PSP variant. The differential diagnosis between them is challenging. Therefore, we studied different ultrasound markers by transcranial sonography in individuals with PSP-RS and PSP-P, to test their value in the diagnostic work up of these patients. METHODS: Transcranial sonography was performed in 21 patients with PSP-RS and 11 patients with PSP-P. Echogenic sizes of the substantia nigra (SN) and the lenticular nuclei (LN), as well as the width of the third ventricle, were measured. RESULTS: Among the patients with PSP-RS and PSP-P, three (14%) and eight (73%) patients had a hyperechogenic SN (P = 0.020), respectively. Uni- or bilateral hyperechogenicity of the LN was observed in 67% and 36% of patients with PSP-RS and PSP-P, respectively (P = 0.101). Third ventricle was significantly wider in patients with PSP-RS (11.2 ±â€…2.3 mm) when compared with patients with PSP-P (7.5 ±â€…1.4 mm; P = 0.001). CONCLUSION: Our data, possibly reflecting pathological differences, primarily contribute supporting the view that the neurodegenerative process differs in the two PSP variants.

Increased total homocysteine level is associated with clinical status and severity of white matter changes in symptomatic patients with subcortical small vessel disease.

OBJECTIVE: Elevated plasma total homocysteine (tHcy) is an independent risk factor for ischemic stroke and has been linked to cerebral small vessel disease (SVD), in particular. Controversy persists as to whether increased tHcy is associated with functional status and cognitive decline in these patients. METHODS: Plasma tHcy, MTHFR polymorphism, vascular risk factors, functional and cognitive status and severity of lesions on MRI, assessed with the Age-Related White Matter Changes (ARWMC) visual grading scale, were analyzed in 95 patients with SVD and 41 healthy control subjects. RESULTS: Plasma tHcy levels were higher in patients with SVD (14.4±5.0 µmol/L) compared to healthy SVD-free controls (8.9±3.9 µmol/L). In SVD patients, tHcy levels strongly correlated with cognitive status (age-adjusted risk 5.8, 95% CI 1.3-25.3, p=0.015), functional status (age-adjusted risk 3.2, 95% CI 1.2-8.8, p=0.022) and severity of MRI lesions (age-adjusted risk 1.2, 95% CI 1.1-1.4; p=0.004). Only total ARWMC score was independently associated with increased tHcy levels (OR 1.2, 95%CI 1.1-1.4, p=0.004). Independent predictors of WMC occurrence were tHcy levels (OR 1.2, 95%CI 1.1-1.3, p=0.003) and mRS score (OR 2.2, 95%CI 1.2-4.1, p=0.017). CONCLUSIONS: In patients with cerebral SVD there is a positive association of increased plasma tHcy levels with clinical status and severity of WMC.

Three-dimensional multivoxel spectroscopy of the healthy hippocampus-are the metabolic differences related to the location?

AIM: The aim of this study was to determine the bilateral distribution of proton metabolites along the long axis of the hippocampus. MATERIALS AND METHODS: Forty-one healthy volunteers were examined using a 1.5T magnetic resonance imaging system, using proton three-dimensional spectroscopic imaging (3D CSI) of the left and the right hippocampus separately. Three dominant signals were measured: choline (Cho), total creatine (tCr), and n-acetylaspartate (NAA) and expressed as ratios of Cho:tCr, NAA:tCr, NAA:Cho and NAA:(Cho+tCr). We compared the data from three hippocampal regions: head, body and tail. RESULTS: Lower NAA:tCr ratios were found in head compared with the body (p<0.05) and in the head compared with the tail (p<0.05) bilaterally. Lower NAA:Cho and NAA:(Cho+tCr) ratios were found in the head compared with the body (p<0.05), in the body compared with the tail (p<0.05), and in the head compared with the tail (p<0.05) bilaterally. There was no statistically significant difference between the left and the right hippocampus. CONCLUSION: Ratios of NAA:tCr, NAA:Cho, and NAA:(Cho+tCr) in hippocampal tissue were significantly higher posteriorly than anteriorly. As the differences are present in healthy volunteers, the appearance in patients related to approximate voxel positioning within hippocampi may result in false-positive results.

Medication overuse headache: clinical features predicting treatment outcome at 1-year follow-up.

We present a prospective study of 240 patients with medication overuse headache (MOH) treated with drug withdrawal and prophylactic medications. At 1-year follow-up, 137 (57.1%) patients were without chronic headache and without medication overuse, eight (3.3%) patients did not improve after withdrawal and 95 (39.6%) relapsed developing recurrent overuse. Age at time of MOH diagnosis, regular use of benzodiazepines, frequency and Migraine Disability Assessment (MIDAS) score of chronic headache, age at onset of primary headache, frequency and MIDAS score of primary headache, ergotamine compound overuse and daily drug intake were significantly different between successfully and unsuccessfully treated patients. Multivariate analysis determined the frequency of primary headache disorder, ergotamine overuse and disability of chronic headache estimated by MIDAS as independent predictors of treatment efficacy at 1-year follow-up.

Symmetry of post-movement beta-ERS and motor recovery from stroke: a low-resolution EEG pilot study.

The inter-hemispheric symmetry of electroencephalographic (EEG) post-movement beta-event-related synchronization (PMBS) after movements on a drawing board was studied in eight acute stroke subjects with mild hemiparesis and eight normal subjects. A follow-up testing was conducted 3 months after the initial recordings with a twofold purpose: (1) to validate the reproducibility of the experimental protocol in normal subjects; and (2) to study changes of inter-hemispheric PMBS-symmetry as a response to recovery of motor function. PMBS values were calculated and their topographic distributions illustrated at various time instances following movement offset. Significant PMBS patterns were present in all normal subjects, with only minor differences within consecutive recordings. The side of hemiparesis in acute stroke subjects could be distinguished (P = 0.04) on the basis of the signed symmetry index, a quantitative measure of lateralization. The follow-up testing on three recovered stroke subjects revealed a trend of changes in the lateralization towards the contralateral side of movement, an indication that the cortical organization of movement following recovery turned out as reported for normal subjects. Further clinical investigations need to be carried out to evaluate the relationship between recovery and PMBS symmetry on a large number of subjects, using the method presented here.

Cluster headache and paroxysmal hemicrania: differential diagnosis.

The utility of the differences between cluster headache (CH) and paroxysmal hemicrania (PH) is limited by the considerable overlap of their clinical characteristics. We compared 54 patients with CH and eight patients with PH in terms of demographic features, characteristics of headache attacks, associated autonomic features, temporal forms of disorders, and response to verapamil. According to our results, clinical features that distinguished CH and PH patients were: maximal pain localization, ocular in CH patients and extra-ocular in PH group; mean attack duration was longer and mean attack frequency was lower in CH patients in comparison with PH patients. Conjuctival injection was the only autonomic sign seen more frequently in CH patients. There were more CH patients with episodic and more PH patients with unremitting form of the disorder in examined groups. Although statistical analysis pointed out a significant difference between these clinical features, there was no clinical characteristic that exclusively belonged to one of these headache entities. Demographic characteristics (age, gender, social background), the other headache attack features (nocturnal attacks, interattack tenderness), the other autonomic signs, as well as the response to verapamil did not differ significantly between two groups.