Cargo adaptors regulate stepping and force generation of mammalian dynein-dynactin.

Cytoplasmic dynein is an ATP-driven motor that transports intracellular cargos along microtubules. Dynein adopts an inactive conformation when not attached to a cargo, and motility is activated when dynein assembles with dynactin and a cargo adaptor. It was unclear how active dynein-dynactin complexes step along microtubules and transport cargos under tension. Using single-molecule imaging, we showed that dynein-dynactin advances by taking 8 to 32-nm steps toward the microtubule minus end with frequent sideways and backward steps. Multiple dyneins collectively bear a large amount of tension because the backward stepping rate of dynein is insensitive to load. Recruitment of two dyneins to dynactin increases the force generation and the likelihood of winning against kinesin in a tug-of-war but does not directly affect velocity. Instead, velocity is determined by cargo adaptors and tail-tail interactions between two closely packed dyneins. Our results show that cargo adaptors modulate dynein motility and force generation for a wide range of cellular functions

CB1 Receptors Regulate Alcohol-Seeking Behavior and Alcohol Self-administration of Female Alcohol-Preferring (P) Rats

Rationale The endogenous cannabinoid (CB) system mediates a number of behaviors associated with drug-seeking and drug self-administration. In this study the effects of CB1 receptor manipulations on operant ethanol (EtOH) responding during EtOH-seeking, EtOH- relapse as well as on-going EtOH self-administration were determined. Methods Alcohol-preferring (P) rats were trained in 2-lever operant chambers to self-administer 15% EtOH (v/v) and water on a concurrent fixed-ratio 5 – fixed-ratio 1 (FR5-FR1) schedule of reinforcement in daily 1-hr sessions. After 10 weeks, rats underwent 7 extinction sessions, followed by 2 weeks in their home cages without access to EtOH or operant chambers. Rats were then returned to the operant chambers for testing of EtOH-seeking behavior (no EtOH present) for 4 sessions. After a week in their home cages following the EtOH-seeking test, rats were returned to the operant chambers with access to EtOH and water (relapse). Rats were then maintained in the operant chambers for daily 1-hr sessions with access to 15% EtOH and water for several weeks. Results The CB1 receptor antagonist (SR141716A), at doses of 1 and 2 mg/kg, i.p. reduced EtOH-seeking and transiently reduced EtOH self-administration during relapse and maintenance. Conversely, treatment with the CB1 receptor agonist CP, 55-940, at doses of 1 and 10 μg/kg i.p., increased EtOH-seeking and EtOH self-administration during relapse. Conclusions The results of this study demonstrate that activation of CB1 receptors are involved in regulating EtOH-seeking as well as the reinforcing effects of EtOH under relapse and on-going self-administration conditions

Serotonin-3 Receptors in the Posterior Ventral Tegmental Area Regulate Ethanol Self-Administration of Alcohol-Preferring (P) Rats

Several studies indicated the involvement of serotonin-3 (5-HT 3 ) receptors in regulating alcohol- drinking behavior. The objective of this study was to determine the involvement of 5-HT 3 receptors within the ventral tegmental area (VTA) in regulating ethanol self-administration by alcohol-preferring (P) rats. Standard two-lever operant chambers were used to examine the effects of 7 consecutive bilateral micro-infusions of ICS205-930 (ICS), a 5-HT 3 receptor antagonist, directly into the posterior VTA on the acquisition and maintenance of 15% (v/v) ethanol self- administration. P rats readily acquired ethanol self-administration by the 4 th session. The three highest doses (0.125, 0.25 and 1.25 ug) of ICS prevented acquisition of ethanol self- administration. During the acquisition post-injection period, all rats treated with ICS demonstrated higher responding on the ethanol lever, with the highest dose producing the greatest effect. In contrast, during the maintenance phase, the 3 highest doses (0.75, 1.0 and 1.25 ug) of ICS significantly increased responding on the ethanol lever; following the 7-day dosing regimen, responding on the ethanol lever returned to control levels. Micro-infusion of ICS into the posterior VTA did not alter the low responding on the water lever, and did not alter saccharin (0.0125% w/v) self-administration.. Micro-infusion of ICS into the anterior VTA did not alter ethanol self- administration. Overall, the results of this study suggest that 5-HT 3 receptors in the posterior VTA of the P rat may be involved in regulating ethanol self-administration. In addition, chronic operant ethanol self-administration, and/or repeated treatments with a 5-HT 3 receptor antagonist may alter neuronal circuitry within the posterior VTA

The stimulating effects of ethanol on ventral tegmental area dopamine neurons projecting to the ventral pallidum and medial prefrontal cortex in female Wistar rats: regional difference and involvement of serotonin-3 receptors

RATIONALE: The ventral tegmental area (VTA) mediates the local stimulating effects of ethanol (EtOH) in a region-dependent manner, with EtOH administration in the posterior but not anterior VTA stimulating the mesolimbic system. The serotonin-3 (5-HT(3)) receptor has been involved in the effects of EtOH on the mesolimbic system. OBJECTIVES: The current study tested the hypothesis that EtOH would stimulate mesopallidal and mesocortical dopamine neurons in the posterior but not anterior VTA and that the stimulating effects of EtOH in the VTA would involve activation of local 5-HT(3) receptors. METHODS: Wistar female rats were surgically implanted with two cannulae, one in one sub-region of the VTA for microinjection and the other in the ventral pallidum (VP) or medial prefrontal cortex (mPFC) for microdialysis. Artificial cerebrospinal fluid or EtOH (200 mg%; 44 mM) was microinjected in the anterior or posterior VTA, and extracellular dopamine was measured in the VP or mPFC with microdialysis-HPLC. RESULTS: EtOH injections in the posterior but not anterior VTA significantly increased extracellular dopamine levels in the VP and mPFC. Co-injections of the 5-HT(3) receptor antagonist ICS-205,930 with EtOH in the posterior VTA significantly reduced the effects of EtOH on extracellular dopamine levels in the VP and mPFC. CONCLUSIONS: The results indicate that posterior VTA dopamine neurons projecting to the VP and mPFC are stimulated by local administration of EtOH and that the local stimulating effects of EtOH are mediated, at least in part, by 5-HT(3) receptors

Nicotine Modulates Alcohol-Seeking and Relapse by Alcohol-Preferring (P) Rats in a Time Dependent Manner

Background— Alcohol is frequently co-abused with smoking. In humans, nicotine use can increase alcohol craving and consumption. The objectives of the current study were to assess the acute effects of nicotine on alcohol seeking and relapse at two different time points. Method— Adult female alcohol-preferring (P) rats were trained in 2-lever operant chambers to self-administer 15% EtOH (v/v) and water on a concurrent fixed-ratio 5 – fixed-ratio 1 (FR5-FR1) schedule of reinforcement in daily 1-hr sessions. Following 10 weeks of daily 1-hr sessions, rats underwent 7 extinction sessions, followed by 2 weeks in their home cages. Rats were then returned to the operant chambers without EtOH or water being present for 4 sessions (Pavlovian Spontaneous Recovery [PSR]). Rats were then given a week in their home cage before being returned to the operant chambers with access to EtOH and water (relapse). Nicotine (0, 0.1, 0.3, or 1.0 mg/kg) was injected s.c. immediately or 4-hr prior to PSR or relapse testing. Results— Injections of nicotine immediately prior to testing reduced (5–10 responses PSR; 50– 60 responses relapse), whereas injections of nicotine 4-hr prior to testing increased (up to 150 responses for PSR; up to 400 responses for relapse with 1.0 mg/kg dose) responses on the EtOH lever during PSR and relapse tests. Discussion— The results of this study demonstrate that acute effects of nicotine on EtOH- seeking and relapse behaviors may be time-dependent, with the immediate effects being a result of nicotine possibly acting as a substitute for EtOH whereas, with a delay of 4-hr, priming effects of nicotine alterations in nicotinic receptors, and/or the effects of nicotine’s metabolites (i.e., cotinine, nornicotine) may enhance the expression of EtOH-seeking and relapse behaviors

Effects of Alcohol and Saccharin Deprivations on Concurrent Ethanol and Saccharin Operant Self-Administration by Alcohol-Preferring (P) Rats

Consumption of sweet solutions has been associated with a reduction in withdrawal symptoms and alcohol craving in humans. The objective of the present study was to determine the effects of EtOH and saccharin (SACC) deprivations on operant oral self-administration. P rats were allowed to lever press concurrently self-administer EtOH (15% v/v) and SACC (0.0125% g/v) for 8 weeks. Rats were then maintained on daily operant access (non-deprived), deprived of both fluids (2 weeks), deprived of SACC and given 2 ml of EtOH daily, or deprived of EtOH and given 2 ml of SACC daily. All groups were then given two weeks of daily operant access to EtOH and SACC, followed by an identical second deprivation period. P rats responded more for EtOH than SACC. All deprived groups increased responding on the EtOH lever, but not on the SACC lever. Daily consumption of 2 ml EtOH decreased the duration of the ADE. Home cage access to 2 ml SACC also decreased the ADE but to a lesser extent than access to EtOH. A second deprivation period further increased and prolonged the expression of an ADE. These results show EtOH is a more salient reinforcer than SACC. With concurrent access to EtOH and SACC, P rats do not display a saccharin deprivation effect. Depriving P rats of both EtOH and SACC had the most pronounced effect on the magnitude and duration of the ADE, suggesting that there may be some interactions between EtOH and SACC in their CNS reinforcing effects

Schoolgirls’ experience and appraisal of menstrual absorbents in rural Uganda: a cross-sectional evaluation of reusable sanitary pads

BACKGROUND: Governments, multinational organisations, and charities have commenced the distribution of sanitary products to address current deficits in girls’ menstrual management. The few effectiveness studies conducted have focused on health and education outcomes but have failed to provide quantitative assessment of girls’ preferences, experiences of absorbents, and comfort. Objectives of the study were, first, to quantitatively describe girls’ experiences with, and ratings of reliability and acceptability of different menstrual absorbents. Second, to compare ratings of freely-provided reusable pads (AFRIpads) to other existing methods of menstrual management. Finally, to assess differences in self-reported freedom of activity during menses according to menstrual absorbent. // METHODS: Cross-sectional, secondary analysis of data from the final survey of a controlled trial of reusable sanitary padand puberty education provision was undertaken. Participants were 205 menstruating schoolgirls from eight schools in rural Uganda. 72 girls who reported using the intervention-provided reusable pads were compared to those using existing improvised methods (predominately new or old cloth). // RESULTS: Schoolgirls using reusable pads provided significantly higher ratings of perceived absorbent reliability across activities, less difficulties changing absorbents, and less disgust with cleaning absorbents. There were no significant differences in reports of outside garment soiling (OR 1.00 95%CI 0.51–1.99), or odour (0.84 95%CI 0.40–1.74) during the last menstrual period. When girls were asked if menstruation caused them to miss daily activities there were no differences between those using reusable pads and those using other existing methods. However, when asked about activities avoided during menstruation, those using reusable pads participated less in physical sports, working in the field, fetching water, and cooking. // CONCLUSIONS: Reusable pads were rated favourably. This translated into some benefits for self-reported involvement in daily activities, although reports of actual soiling and missing activities due to menstruation did not differ. More research is needed comparing the impact of menstrual absorbents on girls’ daily activities, and validating outcome measures for menstrual management research

An Application of a Service-oriented System to Support ArrayAnnotation in Custom Chip Design for Epigenomic Analysis

We present the implementation of an application using caGrid, which is the service-oriented Grid software infrastructure of the NCI cancer Biomedical Informatics Grid (caBIGTM), to support design and analysis of custom microarray experiments in the study of epigenetic alterations in cancer. The design and execution of these experiments requires synthesis of information from multiple data types and datasets. In our implementation, each data source is implemented as a caGrid Data Service, and analytical resources are wrapped as caGrid Analytical Services. This service-based implementation has several advantages. A backend resource can be modified or upgraded, without needing to change other components in the application. A remote resource can be added easily, since resources are not required to be collected in a centralized infrastructure

Towards a free-free template for CMB foregrounds

A full-sky template map of the Galactic free-free foreground emission component is increasingly important for high sensitivity CMB experiments. We use the recently published \ha data of both the northern and southern skies as the basis for such a template. The first step is to correct the \ha maps for dust absorption using the 100 $\mu$m dust maps of Schlegel, Finkbeiner & Davis (1998). We show that for a range of longitudes, the Galactic latitude distribution of absorption suggests that it is 33 per cent of the full extragalactic absorption. A reliable absorption-corrected \ha map can be produced for $\sim 95$ per cent of the sky; the area for which a template cannot be recovered is the Galactic plane area $|b| < 5^{\circ}$, $l=260^{\circ}-0^{\circ}-160^{\circ}$ and some isolated dense dust clouds at intermediate latitudes. The second step is to convert the dust-corrected \ha data into a predicted radio surface brightness. The free-free emission formula is revised to give an accurate expression (1 per cent) for the radio emission covering the frequency range 100 MHz to 100 GHz and the electron temperature range 3000 to 20000 K. The main uncertainty when applying this expression is the variation of electron temperature across the sky. The emission formula is verified in several extended H{\sc ii} regions using data in the range 408 to 2326 MHz. A full-sky free-free template map is presented at 30 GHz; the scaling to other frequencies is given. The Haslam et al. all-sky 408 MHz map of the sky can be corrected for this free-free component, which amounts to a $\approx 6$ per cent correction at intermediate and high latitudes....Comment: 18 pages, 11 figures, accepted for publication in M.N.R.A.S. High-resolution versions of figs 2,7 (in colour), 9 and 11 can be obtained from ftp://ftp.jb.man.ac.uk/pub/cdickins/ff_paper/FINAL_FIGURES