Chronic ethanol exposure differentially regulates NOS1 mRNA levels depending on rat brain area

In vitro experiments were performed on brainstem – spinal cord preparations from mouse neonates to compare the noradrenergic regulations of the respiratory network in the control C3H/HeJ strain and the transgenic Tg8 strain which has been created from the C3H/HeJ strain by deletion of the gene encoding monoamine oxidase A (MAOA), the main enzyme for serotonin degradation. In both control and MAOA-deficient strains, we show: (i) that the pontine A5 area exerts a potent inhibitory modulation on the respiratory rhythm generator; (ii) that noradrenaline application induces a tonic phrenic activity; and (iii) that noradrenaline increases the respiratory rhythm. The latter effect is however delayed and weak in the Tg8 strain. Therefore, MAOA-deficiency has only slightly altered the noradrenergic regulations of the respiratory network.     

Increased resistance to anthelmintics of Haemonchus contortus eggs associated with changes in membrane fluidity of eggshells during embryonation

The embryonation of nematode eggs has been shown to increase their resistance to anthelmintics when parasites are submitted to egg hatch assays. Nevertheless, no mechanism has been suggested to explain this phenomenon. Earlier observations by other authors showed that the biochemical composition of eggshells is altered during the embryonation of eggs. The functional consequences of these changes have not been identified. We studied the changes in membrane environment (eggshells) of Haemonchus contortus eggs during the embryonation by fluidity measurements and their effects on nonspecific mechanisms of resistance to anthelmintics. We previously demonstrated that these mechanisms imply P-glycoproteins (Pgp) belonging to the multi-drug resistance (MDR) system and that the Pgp activity is very susceptible to their lipidic environment. The results obtained here show that the embryonation induced a significant and gradual increase in eggshell fluidity which was associated with an increased resistance to anthelmintics. Differences were observed between H. contortus isolates with various levels of resistance which might result from their specific biology and/or membrane composition. The membrane environment changes could act both on the solubilization of anthelmintics into the eggs and on the efflux of these lipophilic molecules by Pgp.     

Patients’ and Psychologists’ Preferences for Feedback Reports on Expected Mental Health Treatment Outcomes: A Discrete-Choice Experiment

In recent years, there has been an increasing focus on routine outcome monitoring (ROM) to provide feedback on patient progress during mental health treatment, with some systems also predicting the expected treatment outcome. The aim of this study was to elicit patients’ and psychologists’ preferences regarding how ROM system-generated feedback reports should display predicted treatment outcomes. In a discrete-choice experiment, participants were asked 12–13 times to choose between two ways of displaying an expected treatment outcome. The choices varied in four different attributes: representation, outcome, predictors, and advice. A conditional logistic regression was used to estimate participants’ preferences. A total of 104 participants (68 patients and 36 psychologists) completed the questionnaire. Participants preferred feedback reports on expected treatment outcome that included: (a) both text and images, (b) a continuous outcome or an outcome that is expressed in terms of a probability, (c) specific predictors, and (d) specific advice. For both patients and psychologists, specific predictors appeared to be most important, specific advice was second most important, a continuous outcome or a probability was third most important, and feedback that includes both text and images was fourth in importance. The ranking in importance of both the attributes and the attribute levels was identical for patients and psychologists. This suggests that, as long as the report is understandable to the patient, psychologists and patients can use the same ROM feedback report, eliminating the need for ROM administrators to develop different versions.

     

Segment-embedded frame definition affects the hip joint centre precision during walking

Due to marker-specific soft tissue artefacts, the choice of the markers defining the segment-embedded frame affects the functional joint centre location, with subsequent error propagation to joint kinematics and kinetics in gait analysis. Our aim was to assess the effect of the number and placement of markers on the precision of the hip joint centre (HJC) location during walking.Twelve markers (2 x 6) were attached to the pelvis and left thigh of 15 young male subjects. Set-up movements were collected to locate an optimised functional HJC. For all permutations of three from six markers, a HJC was located and subsequently reconstructed in a static trial and during walking. Precision measures with two different definitions of the origin, namely a single maker or their mean-point, and using three, four, five and six were calculated. Finally, marker triads that reduced the variability of the HJC location were determined. Both the number of markers and method for defining the origin significantly affected the HJC precision during static and walking trials. For walking, precision of 39 mm using three markers improved to 5 mm using redundant markers and the mean marker position as the segment origin. Markers placed close to the joint gave more consistent results.     

An aminoacyl-tRNA synthetase-like protein encoded by the Escherichia coli yadB gene glutamylates specifically tRNAAsp

The product of the Escherichia coli yadB gene is homologous to the N-terminal part of bacterial glutamyl-tRNA synthetases (GluRSs), including the Rossmann fold with the acceptor-binding domain and the stem-contact fold. This GluRS-like protein, which lacks the anticodon-binding domain, does not use tRNA(Glu) as substrate in vitro nor in vivo, but aminoacylates tRNA(Asp) with glutamate. The yadB gene is expressed in wild-type E. coli as an operon with the dksA gene, which encodes a protein involved in the general stress response by means of its action at the translational level. The fate of the glutamylated tRNA(Asp) is not known, but its incapacity to bind elongation factor Tu suggests that it is not involved in ribosomal protein synthesis. Genes homologous to yadB are present only in bacteria, mostly in Proteobacteria. Sequence alignments and phylogenetic analyses show that the YadB proteins form a distinct monophyletic group related to the bacterial and organellar GluRSs (alpha-type GlxRSs superfamily) with ubiquitous function as suggested by the similar functional properties of the YadB homologue from Neisseria meningitidis.     

Beta cyclodextrins bind,stabilize, and remove lipofuscin bisretinoids from retinal pigment epithelium

Accumulation of lipofuscin bisretinoids (LBs) in the retinal pigment epithelium (RPE) is the alleged cause of retinal degeneration in genetic blinding diseases (e.g., Stargardt) and a possible etiological agent for age-related macular degeneration. Currently, there are no approved treatments for these diseases; hence, agents that efficiently remove LBs from RPE would be valuable therapeutic candidates. Here, we show that beta cyclodextrins (β-CDs) bind LBs and protect them against oxidation. Computer modeling and biochemical data are consistent with the encapsulation of the retinoid arms of LBs within the hydrophobic cavity of β-CD. Importantly, β-CD treatment reduced by 73% and 48% the LB content of RPE cell cultures and of eyecups obtained from Abca4-Rdh8 double knock-out (DKO) mice, respectively. Furthermore, intravitreal administration of β-CDs reduced significantly the content of bisretinoids in the RPE of DKO animals. Thus, our results demonstrate the effectiveness of β-CDs to complex and remove LB deposits from RPE cells and provide crucial data to develop novel prophylactic approaches for retinal disorders elicited by LBs.The retinal pigment epithelium (RPE), strategically situated between the neural retina and the choroid blood vessels, is essential for photoreceptor (PR) function. It recycles vitamin A, which is required for the visual cycle and clears debris generated by the circadian shedding of PR outer segments (1, 2). Each RPE cell phagocytoses and digests the material produced by 30–50 overlying PRs, which shed 10% of their mass daily. The intense and continual phagocytic activity of RPE cells results in the progressive accumulation of indigestible products or “lipofuscin” in their lysosomal compartment (3, 4). Unlike lipofuscins found in other body tissues, which are composed mainly of protein, RPE lipofuscin consists predominantly of lipid-bisretinoids and only 2% protein (5). Lipofuscin bisretinoids (LBs) are vitamin A-derived side products of the visual cycle. Light converts 11-cis-retinal (11CR), the visual pigment chromophore, into all-trans-retinal (ATR), which is immediately flipped by the ATP-binding cassette transporter 4 (Abca4) transporter from the lumen of the outer segment discs to the cytoplasm, where it is reduced to inert all-trans-retinol by retinol dehydrogenase 8 (Rdh8), in mice (6, 7). Small fractions of 11CR and ATR are converted into N-retinylidine-N-ethanolamine (A2E) and other less abundant bisretinoids, which once accumulated in the lysosomes of RPE cells are refractory to all known lysosomal hydrolases (8, 9). The concept that LB accumulation causes retinal degeneration is supported by in vitro and in vivo data that show that excessive LBs are toxic for cultured RPE cells (10, 11), that photoreceptors overlying A2E-laden RPE are more prone to degeneration (12) and that excessive accumulation of LBs in Stargardt’s disease precedes macular degeneration (13). Mice carrying null mutations in Abca4 and Rdh8 develop blindness, basal laminar deposits, and focal accumulations of extracellular debris between the RPE and the Bruch membrane (drusen) (6).Here we report that a family of modified cyclic oligosaccharides, beta cyclodextrins (β-CDs), formed by seven d-glucose units, can encapsulate the hydrophobic arms of A2E within their nonpolar cavity, protect A2E from oxidation, and remove A2E from RPE cells. Our data demonstrate a direct correlation between the ability of β-CDs to perform these protective functions and their affinity for A2E.     

Chronic ethanol consumption induces tolerance to the spatial memory impairing effects of acute ethanol administration in rats

A large number of studies in rats have investigated the effects of acute and chronic ethanol administration on performance on many spatial learning and memory tasks. However, no study has addressed the problem of whether chronic ethanol consumption induces tolerance to acute ethanol-induced spatial memory deficits. In this study, we analyzed the behavioral effects of acute ethanol administration on spatial memory and locomotor activity in rats chronically intoxicated by ethanol. Male Sprague-Dawley rats were given as their only available liquid source a 10% (v/v) aqueous ethanol solution for 2 weeks before behavioral testing and during the 1-week behavioral testing period. They were treated intraperitoneally with 1.5 g/kg of ethanol 30 min before daily training in the Morris water maze, a spatial memory task sensitive to hippocampal damage. Our results demonstrate that learning and spatial memory of ethanol-consuming animals were not altered compared with control rats. Chronic ethanol consumption had no effect on spatial reference memory in terms of either the distance traveled to find the hidden platform during the acquisition phase of the experiment, or the time spent in the training quadrant during the retention trial. Acute ethanol administration impaired spatial memory in control rats and this impairment was reversed in chronic ethanol-consuming animals, revealing that chronic ethanol consumption did induce tolerance to the spatial memory deficits induced by acute ethanol injection, although plasma ethanol levels did not differ between the two groups. In contrast, chronic ethanol consumption did not induce tolerance to the acute ethanol-induced stimulatory locomotor activity measured in the same animals. Our results, therefore, indicate that chronic ethanol consumption induces tolerance to the cognitive impairing effects, but not to the locomotor stimulatory effects of acute ethanol administration in rats, suggesting that these two behavioral effects of ethanol do not share a common mechanism in the CNS.