Faculty Bibliography

OBJECTIVES/OBJECTIVE:To compare postoperative outcomes in patients prescribed long-acting opioids vs opioid-naïve patients who underwent elective noncardiac surgeries. DESIGN/METHODS:Retrospective cohort study. SETTING/METHODS:Single urban academic institution. METHODS AND SUBJECTS/METHODS:We retrospectively compared postoperative outcomes in long-acting opioid users vs opioid-naïve patients who underwent elective noncardiac surgeries. Inpatient and ambulatory surgery cohorts were separately analyzed. Preoperative medication lists were queried for the presence of long-acting opioids or absence of opioids. Multivariable logistic regression was performed to analyze the impact of long-acting opioid use on readmission rate, respiratory failure, and adverse cardiac events. Multivariable zero-truncated negative binomial regression was used to examine length of stay. RESULTS:After exclusions, there were 93,644 adult patients in the study population, 23,605 of whom underwent inpatient surgeries and 70,039 of whom underwent ambulatory surgeries. After adjusting for potential confounders and inpatient surgeries, preoperative long-acting opioid use was associated with increased risk of prolonged length of stay (incidence rate ratio = 1.1, 99% confidence interval [CI] = 1.0-1.2, P < 0.01) but not readmission. For ambulatory surgeries, preoperative long-acting opioid use was associated with increased risk of all-cause as well as pain-related readmission (odds ratio [OR] = 2.1, 99% CI = 1.5-2.9, P < 0.001; OR = 2.0, 99% CI = 0.85-4.2, P = 0.02, respectively). There were no significant differences for respiratory failure or adverse cardiac events. CONCLUSIONS:The use of preoperative long-acting opioids was associated with prolonged length of stay for inpatient surgeries and increased risk of all-cause and pain-related readmission for ambulatory surgeries. Timely interventions for patients on preoperative long-acting opioids may be needed to improve these outcomes.

Amblyopia, a disorder in which vision through one of the eyes is degraded, arises because of defective processing of information by the visual system. Amblyopia often develops in humans after early misalignment of the eyes (strabismus), and can be simulated in macaque monkeys by artificially inducing strabismus. In such amblyopic animals, single-unit responses in primary visual cortex (V1) are appreciably reduced when evoked by the amblyopic eye compared to the other (fellow) eye. However, this degradation in single V1 neuron responsivity is not commensurate with the marked losses in visual sensitivity and resolution measured behaviorally. Here we explored the idea that changes in patterns of coordinated activity across populations of V1 neurons may contribute to degraded visual representations in amblyopia, potentially making it more difficult to read out evoked activity to support perceptual decisions. We studied the visually-evoked activity of V1 neuronal populations in three macaques (M. nemestrina) with strabismic amblyopia and in one control. Activity driven through the amblyopic eye was diminished, and these responses also showed more interneuronal correlation at all stimulus contrasts than responses driven through the fellow eye or responses in the control. A decoding analysis showed that responses driven through the amblyopic eye carried less visual information than other responses.Our results suggest that part of the reduced visual capacity of amblyopes may be due to changes in the patterns of functional interaction among neurons in V1.

Threat avoidance, particularly from predators, is key for survival. Through the use of optogenetics, viral tracing, and electrophysiological recordings, Zhou and colleagues identified a superior colliculus to ventral tegmental area pathway in detecting alarming visual cues and mediating defensive behaviors in mice. These findings provide novel insight into the neural circuit underlying innate predator defense.

Tremor is the most common movement disorder; however, we are just beginning to understand the brain circuitry that generates tremor. Various neuroimaging, neuropathological, and physiological studies in human tremor disorders have been performed to further our knowledge of tremor. But, the causal relationship between these observations and tremor is usually difficult to establish and detailed mechanisms are not sufficiently studied. To overcome these obstacles, animal models can provide an important means to look into human tremor disorders. In this manuscript, we will discuss the use of different species of animals (mice, rats, fruit flies, pigs, and monkeys) to model human tremor disorders. Several ways to manipulate the brain circuitry and physiology in these animal models (pharmacology, genetics, and lesioning) will also be discussed. Finally, we will discuss how these animal models can help us to gain knowledge of the pathophysiology of human tremor disorders, which could serve as a platform towards developing novel therapies for tremor.

Background: Reduced endocannabinoid "tone" has been posited in the pathophysiology of ASD animal models; children with ASD have been found to have lower peripheral endocannabinoid levels. Additionally, anecdotal reports suggest cannabinoids may be beneficial for some aspects of ASD.
Method(s): Double-blind placebo-controlled comparison (NCT02956226) of whole plant cannabis extract containing cannabidiol (CBD) and DELTA9-tetrahydrocannabinol (THC) in a 20:1 ratio and (2) purified CBD and THC in the same ratio. Participants were 150 children and adolescents with ASD, both males (80%) and females (mean age 11.8 +/-4.1 yrs). They received either placebo or cannabinoids for 12-weeks (testing efficacy) followed by a 4-week washout, and crossed-over to receive another treatment for 12 weeks to further assess tolerability.
Result(s): There were no treatment related severe or serious adverse events. None of the outcomes differed significantly between cannabinoid preparation, in either treatment period. Considering cannabinoids together, in the first period, 43% of 90 children who received cannabinoids were either much or very much improved on the CGI-I compared with 21% of 47 on placebo (p = 0.009). Placebo-cannabinoid differences were not significant on the other primary outcome, the Home Situations Questionnaire for ASD (HSQ-ASD). A positive response on the Social Responsiveness Scale-2 (SRS-2) was defined as 15% decrease or better from baseline. In the first treatment period, 44% of participants who received cannabinoids had a positive response compared with 19% on placebo (p = 0.013). In terms of possible mediators of treatment effects on the SRS-2, male sex and milder ASD symptoms at baseline were independently associated with better response to cannabinoid treatment.
Conclusion(s): Novel pharmacological treatments for the core and comorbid symptoms of ASD are urgently needed. Preclinical studies implicate the endocannabinoid system in the pathophysiology of ASD. In a controlled study of 150 children, a combination of CBD and THC, in a 20:1 ratio, either as a whole plant extract or as pure cannabinoids, improved disruptive behaviors and an index of ASD core symptoms, with relatively few adverse events. These data suggest that further investigation of cannabinoids in ASD is likely to be promising

Appropriate dosing of cystine-binding thiol drugs in the management of cystinuria has been based on clinical stone activity. When new stones form, the dose is increased. Currently, there is no method of measuring urinary drug levels to guide the titration of therapy. Increasing cystine capacity, a measure of cystine solubility, has been promoted as a method of judging the effects of therapy. In this study, we gave increasing doses of tiopronin or D-penicillamine, depending on the patients' own prescriptions, to ten patients with cystinuria and measured cystine excretion and cystine capacity. The doses were 0, 1, 2, 3 g per day, given in two divided doses, and administered in a random order. Going from 0 to 1 g/day led to an increase in cystine capacity from - 39.1 to 130.4 mg/L (P < 0.009) and decreased 24 h cystine excretion from 1003.9 to 834.8 mg/day (P = 0.039). Increasing the doses from 1 to 2 to 3 g/day had no consistent or significant effect to further increase cystine capacity or decrease cystine excretion. Whether doses higher than 1 g/day have additional clinical benefit is not clear from this study. Limiting doses might be associated with fewer adverse effects without sacrificing the benefit of higher doses if higher doses do not offer clinical importance. However, trials with stone activity as an outcome would be desirable.

It is a question many patients ask in stone clinic - does it matter what water I drink? Often patients cite scaling up of their water pipes or kettles as demonstrating the influence that the hardness of the water has on stone formation. This article is protected by copyright. All rights reserved.

Background: Serotonin and dopamine are neurotransmitters associated with multiple psychiatric disorders. How they interact during development to affect subsequent behavior remains unknown. Knockout of the serotonin transporter or administration of selective-serotonin-reuptake inhibitors (SSRIs) during early-life lead to novelty-induced exploration deficits in adulthood.
Method(s): Using a combination of optogenetics, behavioral testing and electrophysiology we tested the effects of perinatal exposure to fluoxetine (PN-FLX) on dopaminergic system's function in the adult. Between 10 to 15 mice per group, male and female, were administered with saline or fluoxetine (10 mg/kg IP) from P2 to P11. Mice were tested after 8 weeks of age.
Result(s): Here we show that Raphe nucleus serotonin neurons activate ventral tegmental area (VTA) dopamine neurons via glutamate cotransmission and that this cotransmission is impaired in postnatally SSRI treated animals. Moreover, we show that the SSRI-induced hypolocomotion is mimicked by blocking serotonin neuron glutamate cotransmission. Optogenetic activation of dopamine neurons rescued this hypolocomotor phenotype.
Conclusion(s): Our data demonstrate that serotonin neurons modulate dopaminergic activity via glutamate cotransmission and that this pathway is developmentally malleable, with high serotonin levels during early life blunting this capacity, resulting in reduced novelty-induced exploration in adulthood

Nanoparticle-mediated drug delivery is especially useful for targets within endosomes because of the endosomal transport mechanisms of many nanomedicines within cells. Here, we report the design of a pH-responsive, soft polymeric nanoparticle for the targeting of acidified endosomes to precisely inhibit endosomal signalling events leading to chronic pain. In chronic pain, the substance P (SP) neurokinin 1 receptor (NK₁R) redistributes from the plasma membrane to acidified endosomes, where it signals to maintain pain. Therefore, the NK₁R in endosomes provides an important target for pain relief. The pH-responsive nanoparticles enter cells by clathrin- and dynamin-dependent endocytosis and accumulate in NK₁R-containing endosomes. Following intrathecal injection into rodents, the nanoparticles, containing the FDA-approved NK₁R antagonist aprepitant, inhibit SP-induced activation of spinal neurons and thus prevent pain transmission. Treatment with the nanoparticles leads to complete and persistent relief from nociceptive, inflammatory and neuropathic nociception and offers a much-needed non-opioid treatment option for chronic pain.

Naturalistic stimuli such as watching a movie while in the scanner provide an ecologically valid paradigm that has the potential of extracting valuable information on how the brain processes complex stimuli in realistic visual and auditory contexts. Naturalistic viewing is also easier to conduct with challenging participant groups including patients and children. Given the high temporal resolution of MEG, in the present study, we demonstrate how a short movie clip can be used to map distinguishable activation and connectivity dynamics underlying the processing of specific classes of visual stimuli such as face and hand manipulations, as well as contrasting activation dynamics for auditory words and non-words. MEG data were collected from 22 healthy volunteers (6 females, 3 left handed, mean age - 27.7 ± 5.28 years) during the presentation of naturalistic audiovisual stimuli. The MEG data were split into trials with the onset of the stimuli belonging to classes of interest (words, non-words, faces, hand manipulations). Based on the components of the averaged sensor ERFs time-locked to the visual and auditory stimulus onset, four and three time-windows, respectively, were defined to explore brain activation dynamics. Pseudo-Z, defined as the ratio of the source-projected time-locked power to the projected noise power for each vertex, was computed and used as a proxy of time-locked brain activation. Statistical testing using the mean-centered Partial Least Squares analysis indicated periods where a given visual or auditory stimuli had higher activation. Based on peak pseudo-Z differences between the visual conditions, time-frequency resolved analyses were performed to assess beta band desynchronization in motor-related areas, and inter-trial phase synchronization between face processing areas. Our results provide the first evidence that activation and connectivity dynamics in canonical brain regions associated with the processing of particular classes of visual and auditory stimuli can be reliably mapped using MEG during presentation of naturalistic stimuli. Given the strength of MEG for brain mapping in temporal and frequency domains, the use of naturalistic stimuli may open new techniques in analyzing brain dynamics during ecologically valid sensation and perception.