Human resource management (HRM) research has documented the importance of high performance work practices (HPWPs) to organizations, and recent efforts have argued for increasing attention to the role ...of line manager implementation of HPWPs. To date, research in this area has focused largely on the organizational or employee implications of HPWP implementation, ignoring the process through which implementation affects outcomes. In this article, we use theory on impression formation to describe the perceptual process through which line manager implementation of HPWPs facilitates the formation of different employee impressions of manager leadership styles. We argue that this process is contingent upon employee attributions of implementation intent, which are influenced by the interaction of employee affective and attributional tendencies with line manager implementation style (i.e., political skill). Our conceptualization of this process contributes to HRM research by demonstrating the benefits of integrating it with leadership theory, as well as identifying the role of interpersonal perceptual processes in the effects of HPWPs.
•We argue that employee characteristics' influence attributions of HPWPs.•We argue that HPWPs are transactional or transformational dependent on context.•We argue that employee attributions affect impression formation of manager leadership.
Background Psychomotor stimulant drugs such as cocaine and amphetamine activate brain dopamine (DA) neurotransmission and support self-administration in humans and laboratory animals. Cocaine ...amplifies DA signaling by blocking the DA transporter (DAT), and this has been described as the most important mechanism underlying cocaine's reinforcing effects. Amphetamine has the added mechanism of reverse transport of intracellular DA through the DAT. Methods We used cocaine and amphetamine self-administration under a fixed-ratio 1 schedule followed by microdialysis in freely moving rats to measure extracellular DA levels and fast scan cyclic voltammetry in brain slices to measure subsecond DA release and uptake parameters. Results Following a high dose (1.5 mg/kg intravenous) cocaine self-administration paradigm (40 injections/day × 5 days), the DAT was markedly less sensitive to cocaine, as measured by microdialysis and voltammetry in the nucleus accumbens core. In contrast, the DAT substrate amphetamine retained the same efficacy at the DAT in cocaine self-administering animals, and amphetamine did not mimic cocaine's effect on the DAT when self-administered. A single session of cocaine self-administration caused a significant decrease in the ability of cocaine to inhibit the DAT, a finding that may provide a neurochemical basis for rapid tolerance. The effects of cocaine returned to normal within a few weeks following cessation of self-administration. Conclusions Here, we, for the first time, demonstrate an in vivo, pharmacologically induced alteration in the sensitivity of the DAT to cocaine that is specific to cocaine, spares DAT and substrate/releaser interactions, and is independent of maximal rate of DA uptake (Vmax ).
There is great interest in outlining biological factors and behavioral characteristics that either predispose or predict vulnerability to substance use disorders. Response to an inescapable novel ...environment has been shown to predict a “drug‐use‐prone” phenotype that is defined by rapid acquisition of cocaine self‐administration. Here, we showed that response to novelty can also predict the neurochemical and behavioral effects of acute and repeated cocaine in rats. We used cocaine self‐administration under a fixed‐ratio 1 schedule followed by fast‐scan cyclic voltammetry in brain slices to measure subsecond dopamine (DA) release and uptake parameters in drug‐use‐prone and ‐resistant phenotypes. Despite no significant differences in stimulated release and uptake, animals with high responses to a novel environment had DA transporters that were more sensitive to cocaine‐induced uptake inhibition, which corresponded to greater locomotor activating effects of cocaine. These animals also acquired cocaine self‐administration more rapidly and, after 5 days of extended access cocaine self‐administration, high‐responding animals showed robust tolerance to DA uptake inhibition by cocaine. The effects of cocaine remained unchanged in animals with low novelty responses. Similarly, the rate of acquisition was negatively correlated with DA uptake inhibition by cocaine after self‐administration. Thus, we showed that tolerance to the cocaine‐induced inhibition of DA uptake coexists with a behavioral phenotype that is defined by increased preoccupation with cocaine as measured by rapid acquisition and early high intake.
There is great interest in outlining biological factors and behavioral characteristics that either predispose or predict vulnerability to substance use disorders. We used cocaine self‐administration under a fixed‐ratio one schedule followed by fast scan cyclic voltammetry in brain slices to measure sub‐second DA release and uptake parameters in drug‐use prone and resistant phenotypes. We show a supersensitivity in the ability of cocaine to inhibit dopamine uptake following acute administration in animals with higher locomotor response to a novel environment. Following a history of cocaine self‐administration, however, tolerance in the ability of cocaine to inhibit dopamine uptake coexists with a behavioral phenotype that is defined by increased preoccupation with cocaine as measured by rapid acquisition and early high intake.
ABSTRACT
Methylphenidate (MPH) is a commonly abused psychostimulant prescribed for the treatment of attention deficit hyperactivity disorder. MPH has a mechanism of action similar to cocaine (COC) ...and is commonly characterized as a dopamine transporter (DAT) blocker. While there has been extensive work aimed at understanding dopamine (DA) nerve terminal changes following COC self‐administration, very little is known about the effects of MPH self‐administration on the DA system. We used fast scan cyclic voltammetry in nucleus accumbens core slices from animals with a 5‐day self‐administration history of 40 injections/day of either MPH (0.56 mg/kg) or COC (1.5 mg/kg) to explore alterations in baseline DA release and uptake kinetics as well as alterations in the interaction of each compound with the DAT. Although MPH and COC have similar behavioral effects, the consequences of self‐administration on DA system parameters were found to be divergent. We show that COC self‐administration reduced DAT levels and maximal rates of DA uptake, as well as reducing electrically stimulated release, suggesting decreased DA terminal function. In contrast, MPH self‐administration increased DAT levels, DA uptake rates and DA release, suggesting enhanced terminal function, which was supported by findings of increased metabolite/DA tissue content ratios. Tyrosine hydroxylase messenger RNA, protein and phosphorylation levels were also assessed in both groups. Additionally, COC self‐administration reduced COC‐induced DAT inhibition, while MPH self‐administration increased MPH‐induced DAT inhibition, suggesting opposite pharmacodynamic effects of these two drugs. These findings suggest that the factors governing DA system adaptations are more complicated than simple DA uptake blockade.
While methylphenidate and cocaine have similar inhibitory mechanisms of action at the dopamine transporter (DAT), the neurochemical consequences of i.v.self‐administration of the two drugs are completely different. While a five‐day history of cocaine self‐administration selectively reduced cocaine potency at the DAT without affecting methylphenidate potency, methylphenidate self‐administration selectively increased its own potency, as measured using voltammetry in the nucleus accumbens core. These findings suggest that the factors governing dopamine system adaptations are more complicated than simple DAT blockade.
Most pediatric nephrologists work in academia. Mentor-mentee relationships provide support and guidance for successful research career. Mentorship program implementation is valuable in medical fields ...for providing research opportunities to young faculty.
The American Society of Pediatric Nephrology (ASPN) established a research mentorship program to (a) assist with matching of appropriate mentor-mentee dyads and (b) establish metrics for desirable mentor-mentee outcomes with two independent components: (1) the grants review workshop, a short-term program providing mentor feedback on grant proposals, and (2) the longitudinal program, establishing long-term mentor-mentee relationships. Regular surveys of both mentors and mentees were reviewed to evaluate and refine the program.
Twelve mentees and 17 mentors participated in the grant review workshop and 19 mentees were matched to mentors in the longitudinal program. A review of NIH RePORTER data indicated that since 2014, 13 NIH grants have been awarded. Mentees in the longitudinal program reported that the program helped most with identifying an outside mentor, improving grant research content, and with general career development. Mentors perceived themselves to be most helpful in assisting with overall career plans. Email communications were preferred over phone or face-to-face communications. Mentees endorsed strong interest in staying in touch with their mentors and 100% of mentors expressed their willingness to serve in the future.
This mentorship program was initiated and supported by a relatively small medical society and has shown early success in cultivating mentoring relationships for a future generation of clinician-scientists.
Objective
This study sought to screen for the burden of work-related posttraumatic stress disorder (PTSD) symptoms in internal medicine residents.
Methods
A cross-sectional survey of internal ...medicine residents from three academic institutions was conducted using the PCL-5 screening tool.
Results
Off all residents surveyed, 5.2% screened positive for PTSD symptoms (
N
= 194). 86.1% of all trainees identified stressors during training. Positive PTSD screens were significantly higher in PGY3 residents (
X
2
= 15.24,
p
= 0.0005). Of all PGY3 residents, 9.8% (
N
= 4) and 14.6% (
N
= 6) of residents screened positive for PTSD symptoms based on absolute and cluster score criteria, respectively. Verbal/physical assault by patients/families/colleagues were triggers for the most cases of positive screens.
Conclusions
Self-reported stressors are highly prevalent in internal medicine trainees. Verbal/physical assault by patients and families appear to be the triggering event for most positive screens. These observations will help with future study designs to quantify the burden of work related PTSD in internal medicine trainee physicians so that appropriate supportive measures can be provided.
The identification of a series of imidazo1,2-b1,2,4triazines with high affinity and functional selectivity for the GABAA α3-containing receptor subtype is described, leading to the identification of ...a clinical candidate, 11. Compound 11 shows good bioavailability and half-life in preclinical species, and it is a nonsedating anxiolytic in both rat and squirrel monkey behavioral models.
OBJECTIVE To estimate the potential public health impact of the findings of the Age-Related Eye Disease Study (AREDS) on reducing the number of persons developing advanced age-related macular ...degeneration (AMD) during the next 5 years in the United States. METHODS The AREDS clinical trial provides estimates of AMD progression rates and of reduction in risk of developing advanced AMD when a high-dose nutritional supplement of antioxidants and zinc is used. These results are applied to estimates of the US population at risk, to estimate the number of people who would potentially avoid advanced AMD during 5 years if those at risk were to take a supplement such as that used in AREDS. RESULTS -->An estimated 8 million persons at least 55 years old in the United States have monocular or binocular intermediate AMD or monocular advanced AMD. --> They are considered to be at high risk for advanced AMD and are those for whom the AREDS formulation should be considered. Of these people, 1.3 million would develop advanced AMD if no treatment were given to reduce their risk. -->If all of these people at risk received supplements such as those used in AREDS, more than 300 000 (95% confidence interval, 158 000-487 000) of them would avoid advanced AMD and any associated vision loss during the next 5 years. --> CONCLUSION If people at high risk for advanced AMD received supplements such as those suggested by AREDS results, the potential impact on public health in the United States would be considerable during the next 5 years.Arch Ophthalmol.2003;121:1621-1624
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