The synthesis of virulence factors in Staphylococcus aureus is controlled by a regulatory RNA molecule, RNAIII, encoded by the agr locus. Transcription of genes coding for secreted toxins and enzymes is stimulated, while transcription of cell‐surface protein genes is repressed by RNAIII. In the case of staphylococcal alpha‐toxin, RNAIII also seems to stimulate translation by an independent mechanism. In this report we show that in a mutant lacking RNAIII the rate of alpha‐toxin (hla) production relative to the cellular concentration of hla mRNA was reduced 10‐fold as compared with the wild‐type strain. A 75% complementarity between the 5′ end of RNAIII and the 5′ untranslated region of the hla transcript suggests a direct interaction between the RNAs. A complex of RNAIII and hla mRNA was demonstrated in extracts of total RNA from the wild‐type strain, and also with in vitro synthesized RNAs. Ribonuclease T1 digestion experiments revealed that the ribosome binding site of the hla transcript is blocked by intramolecular base‐pairing. Hybridization with RNAIII prevents this intramolecular base‐pairing and makes the hla mRNA accessible for translation initiation. This is, to our knowledge, the first example of an ‘antisense RNA’ that stimulates translation of the target mRNA.

Obesity is a risk factor for stroke and neurodegenerative disease. Excess body fat has been linked to impaired glucose metabolism, insulin resistance, and impulsivity and may be a precursor to decline in attention and executive cognitive function. Here, we investigated the effects of high BMI on regional cerebral blood flow (rCBF) using single photon emission computed tomography (SPECT) imaging in healthy subjects. A total of 16 adult men and 20 adult women were recruited from the community between January 2003 and July 2009 as part of a healthy brain study (HBS) conducted at the Amen Clinics, a private medical facility. Participants in the study were screened to exclude medical, neurological, and psychiatric conditions, including substance abuse. Subjects were categorized as normal or overweight according to BMI. Using a two sample t-test, we determined the effects of BMI on rCBF in normal vs. overweight subjects. Subjects were matched for age and gender. Statistical parametric mapping (SPM) revealed a higher BMI in healthy individuals that is associated with decreased rCBF in Broadmann areas 8, 9, 10, 11, 32, and 44, brain regions involved in attention, reasoning, and executive function (P < 0.05, corrected for multiple comparisons). We found that an elevated BMI is associated with decreased rCBF in the prefrontal cortex of a healthy cohort. These results indicate that elevated BMI may be a risk factor for decreased prefrontal cortex function and potentially impaired executive function.

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This is a preliminary report on the safety and efficacy of 1.5 ATA hyperbaric oxygen therapy (HBOT) in military subjects with chronic blast-induced mild to moderate traumatic brain injury (TBI)/post-concussion syndrome (PCS) and post-traumatic stress disorder (PTSD). Sixteen military subjects received 40 1.5 ATA/60 min HBOT sessions in 30 days. Symptoms, physical and neurological exams, SPECT brain imaging, and neuropsychological and psychological testing were completed before and within 1 week after treatment. Subjects experienced reversible middle ear barotrauma (5), transient deterioration in symptoms (4), and reversible bronchospasm (1); one subject withdrew. Post-treatment testing demonstrated significant improvement in: symptoms, neurological exam, full-scale IQ (+14.8 points; p<0.001), WMS IV Delayed Memory (p=0.026), WMS-IV Working Memory (p=0.003), Stroop Test (p<0.001), TOVA Impulsivity (p=0.041), TOVA Variability (p=0.045), Grooved Pegboard (p=0.028), PCS symptoms (Rivermead PCSQ: p=0.0002), PTSD symptoms (PCL-M: p<0.001), depression (PHQ-9: p<0.001), anxiety (GAD-7: p=0.007), quality of life (MPQoL: p=0.003), and self-report of percent of normal (p<0.001), SPECT coefficient of variation in all white matter and some gray matter ROIs after the first HBOT, and in half of white matter ROIs after 40 HBOT sessions, and SPECT statistical parametric mapping analysis (diffuse improvements in regional cerebral blood flow after 1 and 40 HBOT sessions). Forty 1.5 ATA HBOT sessions in 1 month was safe in a military cohort with chronic blast-induced PCS and PTSD. Significant improvements occurred in symptoms, abnormal physical exam findings, cognitive testing, and quality-of-life measurements, with concomitant significant improvements in SPECT.

Summary Abnormal *polyglutamine (polyQ) tracts are the only common feature in nine proteins that each cause a dominant neurodegenerative disorder. In Huntington’s disease (HD), tracts longer than 36 glutamines in the protein huntingtin (htt) cause degeneration. In situ, monoclonal antibody 3B5H10 binds to different htt fragments in neurons in proportion to their toxicity. Here, we determined the structure of the 3B5H10 Fab to 1.9Å by x-ray crystallography. Modeling demonstrates that the paratope forms a groove suitable for binding two β-rich polyQ strands. Using small-angle x-ray scattering (SAXS), we confirmed that the polyQ epitope recognized by 3B5H10 is a compact, two-stranded hairpin within monomeric htt and is abundant in htt fragments unbound to antibody. Thus, disease-associated polyQ stretches preferentially adopt compact conformations. Since 3B5H10 binding predicts degeneration, this compact polyQ structure may be neurotoxic.

Apparent insensitivity to pain, ritualistic patterns of behavior, and improvement in symptoms after administration of opiate receptor blockers implicated the endogenous opioid system in the initiation and maintenance of SIB. This study was designed to determine whether plasma levels of proopiomelanocortin (POMC)-derived peptides, beta-endorphin-like activity (beta E), ACTH, and adrenal cortisol immediately after an episode of SIB predicted subsequent response to an opiate blocker. Blood samples were collected from 10 patients with mental retardation within minutes of a self-injuring act and during an SIB-free control period. On another day, morning and afternoon samples were collected at least one week apart from the other samples. Effects on SIB of naltrexone hydrochloride (NTX) were examined in a double-blind, placebo-controlled crossover study. After an SIB episode, beta E, but not ACTH, was elevated compared with morning levels, p < .003. Patients with increased plasma levels of beta E after SIB had the most positive response to 2 mg/kg NTX, p < .03. Results suggest that changes in the hypothalamic-pituitary-adrenal axis after SIB may predict differences in individual patient response to opiate blockers.

A cross-over study of 24 Ss with self-injurious behavior (SIB) was conducted over a continuous 10-week period. Treatment with naltrexone (NTX) was provided for 3 weeks in a randomized, reversal design with different doses or placebo each week. Videotaped observations (20 hr/subject), neurological examinations, and ratings of adaptive and maladaptive behavior were collected. Treatment with 2 mg/kg NTX produced at least a 50% reduction in SIB in a significant (p < .01) number of Ss. The 1.0 mg/kg was less effective (p < .02), and no significant change was observed at 0.5 mg/kg. Eighteen of 21 Ss achieved at least a 25% reduction in SIB after treatment of at least 1 dose of NTX (p < .0001). More than half of the Ss (52%) had a >50% reduction (p < .001), and a significant number of Ss (33%) decreased SIB by more than 75% after at least 1 dose of NTX. Significant improvement was measured after NTX on measures of learning and attention.

Suicide has a high comorbidity with impulsivity and depression, and finding imaging biomarkers indicative of patients at high risk for suicidal behavior is invaluable to the clinician. Using single-photon emission computed tomography (SPECT) imaging, we have previously reported regional cerebral blood flow (rCBF) decreases in the medial prefrontal cortex, ventral tegmental area and subgenual cingulate cortex (Brodmann area 25 (BA 25)), a region found to be hypoperfused with treatment-resistant depression. From 2007 to 2010, we have extended our analysis to include nine additional completed suicides. In all, 27 healthy, age- and gender-matched subjects from a previously acquired healthy brain study served as controls to our 21 completed suicides. All 21 suicides had been previously diagnosed with depression according to Diagnostic and Statistical Manual of Mental Disorder-IV criterion. Voxel-by-voxel analyses were performed using statistical parametric mapping to compare the differences in technetium-99m hexamethylpropylene amine oxime brain uptake between the groups. Factor analysis of the data identified the top 10 regions of hypoperfusion in the suicidal group, including the bilateral superior frontal lobes, the right precuneus, the rolandic operculum, postcentral gyrus, left caudate and insular cortex. We also demonstrate more focal decreases in rCBF in the subgenual cingulate cortex (BA 25) in 18 subjects, supporting our previous hypothesis that hypoperfusion of BA 25 may be a risk factor for suicide in depressed patients. This work suggests that SPECT might be useful in predicting risk for suicide completion in subjects with depression or treatment-resistant depression. Further investigation of this work is necessary to better understand the predictive value of this finding.