Response to “isolated head tremor: A DAT SPECT and somatosensory temporal discrimination study.”

In response to Ferrazano and colleagues’ observation of normal DAT binding in patients with isolated head tremor but with abnormal STDT, we report normal 123-IBZM SPECT in a cohort of patients with adult-onset idiopathic focal dystonia with cervical dystonia and their unaffected first-degree relatives both with normal and abnormal TDTs. We discuss molecular imaging findings in dystonia.     

Primary writing tremor: report of a case successfully treated with botulinum toxin A injections and discussion of underlying mechanism.

Primary writing tremor (PWT) is a rare motor disorder of unknown etiology, where tremor is elicited primarily or exclusively with writing. We describe a patient with PWT, present a video before and after successful treatment with botulinum toxin type A injections, and discuss a possible underlying dystonic mechanism.     

Dizziness and Panic Disorder: A Review of the Association Between Vestibular Dysfunction and Anxiety

Dizziness is a common and costly condition that causes significant distress and impairment yet often confounds appropriate diagnosis and treatment. Among patients presenting for evaluation and treatment of dizziness, rates of panic disorder are elevated to 5 to 15 times the general population rates. In addition, the limited studies to date of dizziness in patients with panic disorder suggest that panic patients frequently experience significant dizziness and often demonstrate evidence of vestibular dysfunction. In this paper we review studies investigating the relationship between panic disorder and vestibular dysfunction. Currently, there are three main explanatory models for the association between panic disorder and vestibular dysfunction: the psychosomatic model, the somatopsychic model, and the network alarm theory. Systematic investigations of the treatment of patients with vestibular symptoms and panic disorder are lacking, though prevalence, associated costs, and disability suggest that they are needed. Serotonin selective reuptake inhibitors are good candidates for future treatment studies.     

NR4A2 genetic variation in sporadic Parkinson's disease: a genewide approach.

The NR4A2 gene, which may cause autosomal dominant Parkinson's disease (PD), has also been reported to be a susceptibility factor for sporadic PD. Here, we use a haplotype-tagging approach in 802 PD patients and 784 controls and demonstrate that common genetic variation, including NR4A2 haplotypes, does not influence the risk of PD in the Caucasian population.     

Association of VAMP-2 and Syntaxin 1A Genes with Adult Attention Deficit Hyperactivity Disorder

Objective

The etiology of attention deficit hyperactivity disorder (ADHD) has not been entirely clarified yet. Structural and metabolic differences at the prefrontal striatal cerebellary system and the interaction of gene and environment are the main factors that thought to play roles in the etiology. Genetic investigations are performed especially about the dopamine pathways and receptors. In this study; it was aimed to investigate the association of the synaptobrevin-2 (VAMP-2) gene Ins/Del polymorphism and syntaxin 1A gene intron 7 polymorphism, which take place in encoding presynaptic protein, with adult ADHD.

Methods

One hundred thirty-nine patients, having ADHD aging between 18 and 60 years and 106 healthy people as controls were included into the study. DNA samples were extracted from whole blood and genetic analysis were performed.

Results

A significant difference was determined between ADHD and VAMP-2 Ins/Del polymorphism and syntaxin 1A intron 7 polymorphism according to the control group. These polymorphisms were found not to be associated with subtypes of ADHD.

Conclusion

It is supposed that synaptic protein genes together with dopaminergic genes might have roles in the etiology of ADHD.     

COL4A1/A2基因变异与出血性脑血管病及梗死后出血转化研究进展

4型胶原作为基底膜的重要组成部分,与脑出血过程中血脑屏障的破坏相关,是许多出血性脑血管病动物实验中血脑屏障破坏的观测指标之一。随着基因测序及分析技术的发展,借助全基因组关联分析等策略的临床研究发现,COL4A1/A2基因的变异不仅与一些单基因遗传综合征相关,也与散发性出血性脑血管病相关。研究COL4A1/A2变异与脑出血、蛛网膜下腔出血、梗死后出血转化为代表的散发性出血性脑血管病相关性,对于出血性脑血管病的发病机制、高危人群筛查、早期干预、治疗新思路是有益的。     

4‐hydroxy‐2‐nonenal upregulates and phosphorylates cytosolic phospholipase A2 in cultured Ra2 microglial cells via MAPK pathways

Several studies have suggested the involvement of neuroinflammation in the pathomechanism of neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). We recently demonstrated increased levels of protein‐bound 4‐hydroxy‐2‐nonenal (HNE) as a highly reactive lipid peroxidation product and cytosolic phospholipase A₂ (cPLA₂) as a proinflammatory enzyme in glial cells as well as motor neurons in the spinal cord of sporadic ALS patients. However, a link between HNE and cPLA₂ in ALS remains to be determined. To address this issue, we investigated effects of HNE stimulation on the state of cPLA₂ expression in cultured microglial cell line (Ra2). Exposure of Ra2 cells to HNE significantly increased expression levels of cPLA₂ and its activated form phosphorylated at amino acid residue S⁵⁰⁵ (p‐cPLA₂) on immunoblots. Pretreatment of Ra2 cells with the antioxidant N‐acetylcysteine, the extracellular signal‐regulated kinase (ERK) inhibitor PD98059 or the p38 mitogen‐activated protein kinase (MAPK) inhibitor SB203580 prevented the HNE‐induced increased expression of cPLA₂ and p‐cPLA₂. Immunocytochemical analysis revealed that staining for p‐cPLA₂ in Ra2 cells was localized in the cytoplasm and more intense in the HNE‐stimulated group than in the vehicle group. The present results provide in vitro evidence that HNE upregulates and phosphorylates cPLA₂ in microglia via the ERK and p38 MAPK pathways.     

2nd to 4th digit ratio (2D:4D) and number of sex partners: evidence for effects of prenatal testosterone in men

The number of sexual partners per individual (NSP) is an important component of sexual behaviour. Here, we report two studies concerning the relationship between a probable negative correlate of prenatal testosterone, the ratio of the length of 2nd and 4th digits (2D:4D), and NSP in men. The right hand 2D:4D ratio appears to be more strongly related to prenatal testosterone than does the left hand. Accordingly we found: (a) in a sample of 99 German heterosexual male undergraduates right hand 2D:4D (but not left hand 2D:4D) was significantly negatively associated with reported lifetime NSP. The relationship between NSP and 2D:4D was independent of free testosterone, but free testosterone also showed a weak positive association with NSP (b) in a sample of 79 heterosexual and 95 homosexual Austrian men we found a significant negative association between right hand 2D:4D (but not left hand 2D:4D) and reported NSP in past year for heterosexual but not for homosexual men. The association in heterosexuals was independent of age, years of education, occupation and relationship status. We conclude that male NSP is likely to be influenced by the long-term organisational effects of prenatal testosterone. The relationship between NSP and 2D:4D appears to be confined to heterosexual men.     

S100A8 contributes to postoperative cognitive dysfunction in mice undergoing tibial fracture surgery by activating the TLR4/MyD88 pathway

Neuro-inflammation plays a key role in the occurrence and development of postoperative cognitive dysfunction (POCD). Although S100A8 and Toll-like receptor 4 (TLR4) have been increasingly recognized to contribute to neuro-inflammation, little is known about the interaction between S100A8 and TLR4/MyD88 signaling in the process of systemic inflammation that leads to neuro-inflammation. Firstly, we demonstrated that C57BL/6 wide-type mice exhibit cognitive deficit 24 h after the tibial fracture surgery. Subsequently, increased S100A8 and S100A9 expression was found in the peripheral blood mononuclear cells (PBMCs), spleen, and hippocampus of C57BL/6 wide-type mice within 48 h after the surgery. Pre-operative administration of S100A8 antibody significantly inhibited hippocampal microgliosis and improved cognitive function 24 h after the surgery. Secondly, we also observed TLR4/MyD88 activation in the PBMCs, spleen, and hippocampus after the surgery. Compared with those in their corresponding wide-type mice, TLR4^−/− and MyD88^−/− mice showed lower immunoreactive area of microglia in the hippocampal CA3 region after operation. TLR4 deficiency also led to reduction of CD45^hiCD11b⁺ cells in the brain and better performance in both Y maze and open field test after surgery, suggesting a new regulatory mechanism of TLR4-dependent POCD. At last, the co-location of S100A8 and TLR4 expression in spleen after operation suggested a close relationship between them. On the one hand, S100A8 could induce TLR4 activation of CD11b⁺ cells in the blood and hippocampus via intraperitoneal or intracerebroventricular injection. On the other hand, TLR4 deficiency conversely alleviated S100A8 protein-induced hippocampal microgliosis. Furthermore, the increased expression of S100A8 protein in the hippocampus induced by surgery sharply decreased in both TLR4 and MyD88 genetically deficient mice. Taken together, these data suggest that S100A8 exerts pro-inflammatory effect on the occurrence and development of neuro-inflammation and POCD by activating TLR4/MyD88 signaling in the early pathological process of the postoperative stage.     

A family study of DRD3 rs6280, SLC1A2 rs3794087 and MAPT rs1052553 variants in essential tremor

Background/Objective: Despite many data suggesting a role of genetic factors in the risk for essential tremor (ET), the responsible genes have not been identified. We analyzed in ET Spanish families three single nucleotide polymorphisms (SNPs): DRD3 rs6280, SLC1A2 rs3794087, and MAPT rs1052553) previously related to an increased risk for developing the disease.

Methods: We recruited 45 subjects with ET and 13 subjects without tremor belonging to 11 families who were evaluated because of familial tremor. Diagnosis of probable or definite ET was done according to TRIG criteria. Genotyping of the 3 SNPs was done using TaqMan-based qPCR assays. Data were compared with those of healthy controls of our laboratory. Family-based association testing for disease traits was performed as well.

Results: rs6280 and rs3794087 genotype and allelic frequencies did not differ significantly between subjects with ET and healthy controls. However, rs1052553AA genotype and the allele rs1052553A allele were significantly more frequent among ET patients. rs1052553A allele was non-significantly overrepresented in ET patients compared with controls when considering only the more severely affected member of each ET family. Family-based association test for disease traits showed lack of association between ET and the three SNPs studied.

Conclusions: Our results showed a lack of association between rs6280 and rs3794087 with the risk for ET, though a marginal increased risk for ET was observed among the rs1052553A allele carriers, which was not confirmed with a family-based association study.     

Microglia‐derived purines modulate mossy fibre synaptic transmission and plasticity through P2X4 and A1 receptors

Recent data have provided evidence that microglia, the brain‐resident macrophage‐like cells, modulate neuronal activity in both physiological and pathophysiological conditions, and microglia are therefore now recognized as synaptic partners. Among different neuromodulators, purines, which are produced and released by microglia, have emerged as promising candidates to mediate interactions between microglia and synapses. The cellular effects of purines are mediated through a large family of receptors for adenosine and for ATP (P2 receptors). These receptors are present at brain synapses, but it is unknown whether they can respond to microglia‐derived purines to modulate synaptic transmission and plasticity. Here, we used a simple model of adding immune‐challenged microglia to mouse hippocampal slices to investigate their impact on synaptic transmission and plasticity at hippocampal mossy fibre (MF) synapses onto CA3 pyramidal neurons. MF–CA3 synapses show prominent forms of presynaptic plasticity that are involved in the encoding and retrieval of memory. We demonstrate that microglia‐derived ATP differentially modulates synaptic transmission and short‐term plasticity at MF–CA3 synapses by acting, respectively, on presynaptic P2X₄ receptors and on adenosine A₁ receptors after conversion of extracellular ATP to adenosine. We also report that P2X₄ receptors are densely located in the mossy fibre tract in the dentate gyrus–CA3 circuitry. In conclusion, this study reveals an interplay between microglia‐derived purines and MF–CA3 synapses, and highlights microglia as potent modulators of presynaptic plasticity.     

Regulation of oligodendrocyte differentiation: Protein kinase C activation prevents differentiation of O2A progenitor cells toward oligodendrocytes

Oligodendrocytes differentiate on a specific schedule in vivo in order to myelinate axons at the precise time and at the appropriate position. The current study was undertaken to obtain further insight as to how this timed appearance is regulated intracellularly. We observed that exposure of O2A progenitor cells in culture to phorbol 12-myristate 13-acetate (PMA; an activator of protein kinase C, PKC) inhibited their differentiation to oligodendrocytes by suppressing the expression of specific myelin markers at the O4-stage. To positively identify a role of PKC per se in differentiation, the use of a minimal medium with low serum content turned out to be essential. This was demonstrated by showing that the inhibitory effect of PMA on oligodendrocyte differentiation could be completely abolished by a combined action of insulin, triiodothyronine (T3), hydrocortisone and other components of a chemically defined medium (CDM). Furthermore, the PMA-mediated inhibition of oligodendrocyte differentiation could be partially restored by activation of the cAMP signal transduction pathway. The results indicate that PKC plays a crucial role in the differentiation of O2A progenitor cells toward oligodendrocytes: PKC activation prevents differentiation of O2A progenitor cells, whereas differentiation toward oligodendrocytes is dependent on other signaling compounds which may counteract the PKC signal transduction route. GLIA 22:121–129, 1998. © 1998 Wiley-Liss, Inc.     

Cerebral small vessel disease with hemorrhagic stroke related to COL4A1 mutation: A case report

Stroke is a major cause of mortality and morbidity with a wide variety of etiological risk factors. Cerebral small vessel disease (SVD) is an important cause of stroke in the young with several hereditary disorders affecting these small blood vessels. Mutations in the COL4A1 gene (COL4A1) have been shown to be associated with a broad range of disorders including hemorrhagic stroke, myopathy, glaucoma and others. We report a rare case of stroke in an intellectually disabled 18-year-old girl with radiological evidence of basal ganglia microbleeds, periventricular white matter signal changes and porencephalic cyst. Ophthalmic examination revealed bilateral microcornea and Axenfeld–Rieger anomaly. At autopsy there were hemorrhagic lesions at multiple sites within the brain. Histology revealed thickened small-caliber vessels which demonstrated disruption and fragmentation of the basement membrane by collagen type IV alpha 1 immunohistochemistry and by electron microscopy. A missense COL4A1 mutation involving glycine residue was detected in the patient. The present case illustrates the clinicopathological spectrum of COL4A1-related cerebral SVD presenting as hemorrhagic stroke in the young with porencephaly, intellectual disability, and Axenfield–Rieger anomaly and thus adds to the clinical heterogeneity of this genetic disorder.