Elevated CSF dynorphin A [1-8] in Tourette's syndrome

A recent neuropathological study has reported decreased levels of dynorphin A immunoreactivity in striato-pallidal fibers in the brain of a patient with severe Gilles de la Tourette's syndrome (TS). This observation, taken with the neuroanatomic distribution of dynorphin and its broad range of motor and behavioral effects, has led to speculation concerning its role in the pathobiology of TS. We report on the presence of elevated concentrations of dynorphin A [1-8] in the CSF of 7 TS patients, aged 20 to 45 years. The increase in CSF dynorphin was found to be associated with the severity of the obsessive compulsive symptoms but not with tic severity in these patients. Although CSF studies lack the precision necessary to address questions of selective involvement of neuronal system in specific CNS locations, these findings suggest that endogenous opioids are involved in the pathobiology of TS and related disorders. Tourette's syndrome (TS) is a chronic neuropsychiatric disorder of childhood onset that is characterized by multiple motor and phonic tics that wax and wane in severity and an array of behavioral problems including some forms of obsessive compulsive disorder (OCD) (1). Once thought to be a rare condition, the prevalence of TS is now estimated to be one case per 1,000 boys and one case per 10,000 girls, and milder variants of the syndrome are likely to occur in a sizeable percentage of the population (2). Although the etiology of TS remains unknown, the vertical transmission of TS within families follows a pattern consistent with an autosomal dominant form of inheritance (3,4). Neurobiologic and pharmacological data have implicated central monoaminergic and neuropeptidergic systems in the pathophysiology of TS, and basal ganglia structures remain the prime candidates as the neuroanatomical origin for TS and related conditions (1). Endogenous opioids, including dynorphin and met-enkephalin are concentrated in structures of the basal ganglia (5), are known to interact with central dopaminergic neurons (6, 7), and may play an important role in the control of motor functions (8). Post-mortem brain studies have directly implicated opioids in the pathophysiology of Parkinson's disease (9), Huntington's disease (10), and most recently in TS (11). The neuropathological study of Haber et al. (11) reported decreased levels of dynorphin A [1-17] immunoreactivity in striatal fibers projecting to the globus pallidus in the brain of a patient with severe TS. This ovservation, taken with the neuroanatomic distribution of dynorphin and its broad range of motor and behavioral effects, has led to speculation concerning its role in the pathobiology of TS.(ABSTRACT TRUNCATED AT 400 WORDS)     

No evidence for a major role of polymorphisms during bupropion treatment

This study evaluated the ability of polymorphisms in five candidate genes to predict weight gain among patients taking bupropion or placebo in a smoking cessation trial. Five hundred fifty-three smokers were enrolled into a randomized double-blind, placebo-controlled trial and followed for 12 months. Five candidate genes [DRD2 Taq1 (rs1800497), DRD2-141 (rs1799732), C957T (rs6277), COMT (rs4818), and SLC6A3] were genotyped. Weights at baseline, at end of treatment, and after 6 and 12 months of follow-up were self-reported. Smoking abstinence at each endpoint was self-reported and confirmed biochemically. A self-reported average weight gain after 12 months of 1.1 +/- 6.0 kg (mean +/- standard deviation) in the bupropion group and 1.8 +/- 4.8 kg in the placebo group was noted. For subjects with biochemically confirmed abstinence from smoking, the HL genotype (alleles coding Val at codon 108 are denoted as H, and those coding Met are denoted as L) at the COMT locus and A1A1 genotype at the DRD2 Taq1 locus were associated with less weight gain at the end of treatment. The TC genotype at the C957T locus was associated with increased weight gain at 6 months of follow-up. However, no polymorphisms or their interactions with bupropion consistently and significantly predicted baseline BMI or weight change during treatment for all study subjects. Overall, our results do not support a major role for these five candidate genes in weight gain after smoking cessation.     

Stuttered swallowing: Electric stimulation of the right insula interferes with water swallowing. A case report

Background  

Various functional resonance imaging, magnetoencephalographic and lesion studies suggest the involvement of the insular cortex in the control of swallowing. However, the exact location of insular activation during swallowing and its functional significance remain unclear.     

New solvent-producing Clostridium sp. strains, hydrolyzing a wide range of polysaccharides, are closely related to Clostridium butyricum

Thirteen new Clostridium strains, previously isolated from soil and found to produce high amounts of solvents from glucose, hydrolyzed a great variety of α- and β-glycans, including raw starch, xylan, pectin, inulin and cellulose. The sequences of the PCR-amplified DNA fragments containing the variable 3′ part of one of the 16S rRNA genes were 99.5% identical. The macrorestriction pattern of two endonucleolytic digests of chromosomal DNA in the pulsed-field gel electrophoresis (PFGE) confirmed their high homogeneity on the DNA level. The complete 16S rRNA gene sequence of three selected strains was 99.8% identical to the 16S rRNA gene sequence from Clostridium butyricum and separates them from C. acetobutylicum. To the closely related four species of solventogenic clostridia a new group of strains has to be added, which has a great potential for the direct fermentation of biomass. Journal of Industrial Microbiology & Biotechnology (2001) 27, 329–335. Received 12 September 2000/ Accepted in revised form 25 July 2001     

Quantitative genetic study of maximal electroshock seizure threshold in mice: evidence for a major seizure susceptibility locus on distal chromosome 1

We conducted a quantitative trait locus (QTL) mapping study to dissect the multifactorial nature of maximal electroshock seizure threshold (MEST) in C57BL/6 (B6) and DBA/2 (D2) mice. MEST determination involved a standard paradigm in which 8- to 12-week-old mice received one shock per day with a daily incremental increase in electrical current until a maximal seizure (tonic hindlimb extension) was induced. Mean MEST values in parental strains were separated by over five standard deviation units, with D2 mice showing lower values than B6 mice. The distribution of MEST values in B6xD2 F2 intercrossed mice spanned the entire phenotypic range defined by parental strains. Statistical mapping yielded significant evidence for QTLs on chromosomes 1, 2, 5, and 15, which together explained over 60% of the phenotypic variance in the model. The chromosome 1 QTL represents a locus of major effect, accounting for about one-third of the genetic variance. Experiments involving a congenic strain (B6.D2-Mtv7(a)/Ty) enabled more precise mapping of the chromosome 1 QTL and indicate that it lies in the genetic interval between markers D1Mit145 and D1Mit17. These results support the hypothesis that the distal portion of chromosome 1 harbors a gene(s) that has a fundamental role in regulating seizure susceptibility.