Chronic Methamphetamine Administration Causes Differential Regulation of Transcription Factors in the Rat Midbrain

Methamphetamine (METH) is an addictive and neurotoxic psychostimulant widely abused in the USA and throughout the world. When administered in large doses, METH can cause depletion of striatal dopamine terminals, with preservation of midbrain dopaminergic neurons. Because alterations in the expression of transcription factors that regulate the development of dopaminergic neurons might be involved in protecting these neurons after toxic insults, we tested the possibility that their expression might be affected by toxic doses of METH in the adult brain. Male Sprague-Dawley rats pretreated with saline or increasing doses of METH were challenged with toxic doses of the drug and euthanized two weeks later. Animals that received toxic METH challenges showed decreases in dopamine levels and reductions in tyrosine hydroxylase protein concentration in the striatum. METH pretreatment protected against loss of striatal dopamine and tyrosine hydroxylase. In contrast, METH challenges caused decreases in dopamine transporters in both saline- and METH-pretreated animals. Interestingly, METH challenges elicited increases in dopamine transporter mRNA levels in the midbrain in the presence but not in the absence of METH pretreatment. Moreover, toxic METH doses caused decreases in the expression of the dopamine developmental factors, Shh, Lmx1b, and Nurr1, but not in the levels of Otx2 and Pitx3, in saline-pretreated rats. METH pretreatment followed by METH challenges also decreased Nurr1 but increased Otx2 and Pitx3 expression in the midbrain. These findings suggest that, in adult animals, toxic doses of METH can differentially influence the expression of transcription factors involved in the developmental regulation of dopamine neurons. The combined increases in Otx2 and Pitx3 expression after METH preconditioning might represent, in part, some of the mechanisms that served to protect against METH-induced striatal dopamine depletion observed after METH preconditioning

Limitations in clinical outcome after posterior stabilization of thoracolumbar fractures do not correlate with dynamic trunk muscle dysfunction: an ultrasound controlled prospective cohort study

Background and Purpose Posterior stabilization of the spine is associated with iatrogenic muscle damage. This is discussed to represent an important cause of postoperative pain, especially in open reduction and fixation. The aim of this study was to visualize muscular changes after open or percutaneous posterior stabilization of traumatic thoracolumbar spine fractures and to investigate whether or not these changes are related to the clinical outcome. Methods This prospective cohort study was performed between 05/2012 and 10/2014. A group of posteriorly stabilized patients (study group; SG) with traumatic fractures (AOSpine Type A3 or A4) of the thoracolumbar junction (T11–L2) without neurological deficit were matched to a healthy control group (CG) by age, gender and body mass index. Follow-up: 12 months after surgery. Parameters: muscle size, voluntary muscular activation (VMA) using a standardized ultrasound protocol and standardized questionnaires (VAS Spine Score; ODI; SF-36) were analyzed. Statistics: SPSS (Version 20, 76 Chicago, IL, USA). T test, Chi squared test, analysis of variance and a correlation analysis were performed. Significance level was at p  0.07; NS). Conclusion In surgically treated A3 and A4 fractures, there is continuous muscular deficit 1 year after surgery as documented by ultrasound and clinical control. But, by means of our study we conclude that those muscular deficits alone seem not to be decisive for the clinical outcome 1 year after surgery

Sulfur-driven autotrophic denitrification: Diversity, biochemistry, and engineering applications

Sulfur-driven autotrophic denitrification refers to the chemolithotrophic process coupling denitrification with the oxidation of reduced inorganic sulfur compounds. Ever since 1904, when Thiobacillus denitrificans was isolated, autotrophic denitrifiers and their uncultured close relatives have been continuously identified from highly diverse ecosystems including hydrothermal vents, deep sea redox transition zones, sediments, soils, inland soda lakes, etc. Currently, 14 valid described species within α-, β-, γ-, and ε-Proteobacteria have been identified as capable of autotrophic denitrification. Autotrophic denitrification is also widely applied in environmental engineering for the removal of sulfide and nitrate from different water environments. This review summarizes recent researches on autotrophic denitrification, highlighting its diversity, metabolic traits, and engineering applications. © 2010 Springer-Verlag.link_to_subscribed_fulltex

Changes in head and neck position affect elbow joint position sense

Changes in the position of the head and neck have been shown to introduce a systematic deviation in the end-point error of an upper limb pointing task. Although previous authors have attributed this to alteration of perceived target location, no studies have explored the effect of changes in head and neck position on the perception of limb position. This study investigated whether changes in head and neck position affect a specific component of movement performance, that is, the accuracy of joint position sense (JPS) at the elbow. Elbow JPS was tested with the neck in four positions: neutral, flexion, rotation and combined flexion/rotation. A target angle was presented passively with the neck in neutral, after a rest period; this angle was reproduced actively with the head and neck in one of the test positions. The potential effects of distraction from head movement were controlled for by performing a movement control in which the head and neck were in neutral for the presentation and reproduction of the target angle, but moved into flexion during the rest period. The absolute and variable joint position errors (JPE) were greater when the target angle was reproduced with the neck in the flexion, rotation, and combined flexion/rotation than when the head and neck were in neutral. This study suggests that the reduced accuracy previously seen in pointing tasks with changes in head position may be partly because of errors in the interpretation of arm position