Sudden Stopping in Patients with Cerebellar Ataxia

Stopping during walking, a dynamic motor task frequent in everyday life, is very challenging for ataxic patients, as it reduces their gait stability and increases the incidence of falls. This study was conducted to analyse the biomechanical characteristics of upper and lower body segments during abrupt stopping in ataxic patients in order to identify possible strategies used to counteract the instability in the sagittal and frontal plane. Twelve patients with primary degenerative cerebellar ataxia and 12 age- and sex-matched healthy subjects were studied. Time–distance parameters, dynamic stability of the centre of mass, upper body measures and lower joint kinematic and kinetic parameters were analysed. The results indicate that ataxic patients have a great difficulty in stopping abruptly during walking and adopt a multi-step stopping strategy, occasionally with feet parallel, to compensate for their inability to coordinate the upper body and to generate a well-coordinated lower limb joint flexor–extensor pattern and appropriate braking forces for progressively decelerating the progression of the body in the sagittal plane. A specific rehabilitation treatment designed to improve the ability of ataxic patients to transform unplanned stopping into planned stopping, to coordinate upper body and to execute an effective flexion–extension pattern of the hip and knee joints may be useful in these patients in order to improve their stopping performance and prevent falls.     

猪精子细胞中胰岛素诱导产生的一氧化氮自由基促进精子获能

近期,胰岛素被证实具有诱导猪精子获能的能力。在不同的哺乳动物中,精子获能被认为与一氧化氮信号通路相关;因此,本研究使用荧光激活细胞分选技术探究经胰岛素处理的猪精子中一氧化氮水平。在同一样本中,用金霉素染色、蛋白质酪氨酸磷酸化模式和顶体状态来评估精子获能。结果显示经胰岛素处理的精子内一氧化氮水平及三种评价精子获能的指标均有显著提高;相反,用一氧化氮合成酶抑制剂（N-硝基-L-精氨酸甲酯）或抗胰岛素受体β抗体预处理的精子中胰岛素相关的作用全被逆转。这些结果表明胰岛素具有增强猪精子细胞内一氧化氮浓聚的能力并且提示胰岛素可能通过一氧化氮促进精子获能。     

Ischaemic stroke provoked by sexual intercourse

The association between long term risk factors and stroke has been well established, but very little is known about factors that may precipitate acute stroke. We describe two young women presenting with ischaemic stroke triggered by sexual intercourse. Patient 1 presented with a cardioembolic stroke probably secondary to the interaction between a patent foramen ovale and thrombophilic abnormalities; Patient 2, presenting with orgasmic headache, had a cryptogenic striatocapsular infarct. Sexual intercourse should be considered as an unusual, but possible, trigger of cerebral ischaemia, especially in young patients presenting with cryptogenic stroke.     

Autism in community pre-schoolers: Developmental profiles

Autism is often a complex developmental disorder. The aim of the present study was to describe the developmental characteristics of 129 1–4-year-old children (102 boys, 27 girls) referred for clinical assessment (mean age 2.9 years) due to suspicion of autism spectrum disorder (ASD) after community screening at Child Health Care centers. All children were clinically assessed at the Child Neuropsychiatry Clinic (CNC) in Gothenburg by a research team (neurodevelopmental examination, structured interviews and general cognitive and language examinations). Of the 129 children, 100 met diagnostic criteria for ASD (69 with autistic disorder, and 31 with atypical autism/pervasive developmental disorder-not otherwise specified). The remaining 29 children had a variety of developmental disorders, most often attention-deficit/hyperactivity disorder (ADHD), language disorder, borderline intellectual functioning, and intellectual developmental disorder (IDD) with (n = 25) or without (n = 4) autistic traits (AT). IDD was found in 36% of the 100 children with ASD, and in 4% of the 25 children with AT. Of the children with ASD, 56% had language disorder with no or just a few words at the initial assessment at the CNC, many of whom in combination with IDD. Hyperactivity was found in 37% of those with ASD and in 40% of those with AT. Epilepsy was found in 6% of the total group and in 7% of those with a diagnosis of ASD. Of the latter group 11% had a history of regression, while none of the AT cases had a similar background. When results were compared with a non-screened preschool ASD group of 208 children, referred for ASD intervention at a mean age of 3.4 years, very similar developmental profiles were seen. In conclusion, early community ASD screening appears to systematically identify those children who are in need of intervention and follow-up.     

Differential glial activation during the degeneration of Purkinje cells and mitral cells in the PCD mutant mice

Purkinje Cell Degeneration (PCD) mice harbor a nna1 gene mutation which leads to an early and rapid degeneration of Purkinje cells (PC) between the third and fourth week of age. This mutation also underlies the death of mitral cells (MC) in the olfactory bulb (OB), but this process is slower and longer than in PC. No clear interpretations supporting the marked differences in these neurodegenerative processes exist. Growing evidence suggests that either beneficial or detrimental effects of gliosis in damaged regions would underlie these divergences. Here, we examined the gliosis occurring during PC and MC death in the PCD mouse. Our results demonstrated different glial reactions in both affected regions. PC disappearance stimulated a severe gliosis characterized by strong morphological changes, enhanced glial proliferation, as well as the release of pro‐inflammatory mediators. By contrast, MC degeneration seems to promote a more attenuated glial response in the PCD OB compared with that of the cerebellum. Strikingly, cerebellar oligodendrocytes died by apoptosis in the PCD, whereas bulbar ones were not affected. Interestingly, the level of nna1 mRNA under normal conditions was higher in the cerebellum than in the OB, probably related to a faster neurodegeneration and stronger glial reaction in its absence. The glial responses may thus influence the neurodegenerative course in the cerebellum and OB of the mutant mouse brain, providing harmful and beneficial microenvironments, respectively. © 2012 Wiley Periodicals, Inc.     

Immunohistochemical localization of TRPC6 in the rat substantia nigra

Transient receptor potential channels (TRPC) are plasma membrane, nonselective cationic channels and have been proposed as candidates involved in the regulation of cellular Ca2+ influx [D.E. Clapham, L.W. Runnels, C., Strubing, The TRP ion channel family, Nat. Rev. Neurosci. 2 (2001) 387-396; A. Martorana, C. Giampa, Z. DeMarch, M.T. Viscomi, S. Patassini, G. Sancesario, G. Bernardi, F.R. Fusco, Distribution of TRPC1 receptors in dendrites of rat substantia nigra: a confocal and electron microscopy study, Eur. J. Neurosci. 24 (2006) 732-738]. Studies on regional localization patterns of TRPCs are necessary to provide helpful guidelines for correlating current types with particular channels. In this study, we examined the distribution of one particular member of TRPC superfamily, namely, TRPC6, in the substantia nigra of normal rat brain. Single and double label immunohistochemistry were employed to perform both light and confocal microscopy observations. Our single label studies showed that, in the substantia nigra, TRPC6 labeled the perikarya with a diffuse and intense immunoreaction product distributed throughout cell cytoplasm whereas only a light immunostaining was observed in the cell nuclei. No labeling of axon or terminals was observed, although TRPC6 was evenly distributed in the neuropil. Our dual label studies showed a TRPC6 immunoreactivity pattern that was localized into the proximal dendrites and axon hillock of the large dopaminergic neurons identified by TH immunoreaction. Furthermore, our double label immunofluorescence study for TRPC6 and mGluR1 showed a complete co-localization of the two markers in the substantia nigra. Moreover, TRPC6 did not co-localize with synaptophysin. Thus, our study shows the postsynaptic localization of TRPC6 and its association with mGluR1 in the midbrain dopamine neurons.     

Tau Phosphorylation is Impacted by Rare <Emphasis Type="Italic">AKAP9</Emphasis> Mutations Associated with Alzheimer Disease in African Americans

We studied the effect of two rare mutations (rs144662445 and rs149979685) in the A-kinase anchoring protein 9 (AKAP9) gene, previously associated with Alzheimer disease (AD) in African Americans (AA), on post-translational modifications of AD-related pathogenic molecules, amyloid precursor protein (APP) and microtubule-associated protein Tau using lymphoblastoid cell lines (LCLs) from 11 AA subjects with at least one AKAP9 mutation and 17 AA subjects lacking these mutations. LCLs were transduced by viral vectors expressing causative AD mutations in APP or human full-length wild type Tau. Cell lysates were analyzed for total APP, Aβ₄₀, and total and T181 phospho-Tau (pTau). AKAP9 mutations had no effect on Aβ₄₀/APP, but significantly increased pTau/Tau ratio in LCLs treated with phosphodiesterase-4 inhibitor rolipram, which activates protein kinase A. Proteomic analysis of Tau interactome revealed enrichment of RNA binding proteins and decrease of proteasomal molecules in rolipram-treated cells with AKAP9 mutations. This study shows the impact of rare functional AKAP9 mutations on Tau, a central mechanism of AD pathogenesis, in LCLs derived from AD and control subjects.