Nicotine Produces a High-Approach, Low-Avoidance Phenotype in Response to Alcohol-Associated Cues in Male Rats.

BACKGROUND: Nicotine and alcohol use are highly comorbid. Modulation of drug-paired extrinsic and intrinsic cues likely plays a role in this interaction, as cues can acquire motivational properties and augment drug seeking. The motivational properties of cues can be measured through Pavlovian conditioning paradigms, in which cues either elicit approach following pairing with the reinforcing properties of alcohol or elicit avoidance following pairing with the aversive consequences of alcohol. The present experiments tested whether nicotine would enhance the incentive properties of an appetitive ethanol (EtOH) cue and diminish the avoidance of an aversive EtOH cue in Pavlovian paradigms. METHODS: In experiment 1, male Long-Evans rats with or without prior chronic intermittent access to EtOH were administered nicotine or saline injections prior to Pavlovian conditioned approach (PavCA) sessions, during which conditioned approach to the cue ("sign-tracking") or the EtOH delivery location ("goal-tracking") was measured. In experiment 2, male Long-Evans rats were administered nicotine or saline injections prior to pairing a flavor cue with increasing doses of EtOH (i.p.) in an adaptation of the conditioned taste avoidance (CTA) paradigm. RESULTS: Results from PavCA indicate that, regardless of EtOH exposure, nicotine enhanced responding elicited by EtOH-paired cues with no effect on a similar cue not explicitly paired with EtOH. Furthermore, nicotine reduced sensitivity to EtOH-induced CTA, as indicated by a rightward shift in the dose-response curve of passively administered EtOH. The ED50 , or the dose of EtOH that produced a 50% reduction in intake relative to baseline, was significantly higher in nicotine-treated rats compared to saline-treated rats. CONCLUSIONS: We conclude that nicotine increases the approach and diminishes the avoidance elicited by Pavlovian cues paired, respectively, with the reinforcing and aversive properties of EtOH consumption in male rats. As such, nicotine may enhance alcoholism liability by engendering an attentional bias toward cues that predict the reinforcing outcomes of drinking.

An Increase in Same-day Discharge After Total Joint Arthroplasty During the COVID-19 Pandemic Does Not Influence Patient Outcomes: A Retrospective Cohort Analysis.

Background: The coronavirus disease 2019 (COVID-19) pandemic caused major transitions in total joint arthroplasty (TJA), notably with the increased utilization of same-day discharge (SDD) pathways. This study assessed the effect of accelerated discharge pathways following the resumption of elective cases during the COVID-19 pandemic on SDD rates, adverse events, and characteristics associated with successful SDD following total hip and total knee arthroplasty. Methods: This retrospective study split patients into cohorts: TJA prior to COVID-19 (pre-COVID, July 2019-December 2019) and TJA following the resumption of elective surgeries (post-COVID, July 2020-December 2020). Patient characteristics such as age, sex, body mass index, American Society of Anesthesiologists score, and pertinent comorbidities were analyzed, and length of stay, 30-day emergency department (ED) visit rates, readmissions, and reoperations were compared. Results: A total of 1333 patients met inclusion criteria that were divided into pre-COVID (692) and post-COVID (641) cohorts. The pre-COVID group had a median age of 69 years (interquartile range 63-76), and the post-COVID group had a median age of 68 years (interquartile range 61-75) (P = .024). SDD increased from 0.1% to 28.9% (P < .001), and length of stay decreased from 1.3 days to 0.89 days (P < .001). There was no change in 30-day ED visits, readmissions, or reoperations (P = .817, P = .470, and P = .643, respectively). There was no difference in ED visits, readmissions, or reoperations in SDD patients. The odds of SDD were associated with age (P < .001, odds ratio [OR] = 0.94), body mass index (P = .006, OR = 0.95), male sex (P < .001, OR = 1.83), and history of tobacco use (P < .001, OR = 1.87). Conclusions: At our institution, the COVID-19 pandemic accelerated the utilization of SDD pathways without increasing ED visits, readmissions, or reoperations.