placebo administration
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Author(s):  
Joseph C. Watso ◽  
Mu Huang ◽  
Luke Belval ◽  
Frank A. Cimino III ◽  
Caitlin P. Jarrard ◽  
...  

Our knowledge about how low-dose (analgesic) fentanyl affects autonomic cardiovascular regulation is primarily limited to animal experiments. Notably, it is unknown if low-dose fentanyl influences human autonomic cardiovascular responses during painful stimuli in humans. Therefore, we tested the hypothesis that low-dose fentanyl reduces perceived pain and subsequent sympathetic and cardiovascular responses in humans during an experimental noxious stimulus. Twenty-three adults (10F/13M; 27±7 y; 26±3 kg•m-2, mean ± SD) completed this randomized, crossover, placebo-controlled trial during two laboratory visits. During each visit, participants completed a cold pressor test (CPT; hand in ~0.4 °C ice bath for two minutes) before and five minutes after drug/placebo administration (75 μg fentanyl or saline). We compared pain perception (100 mm visual analog scale), muscle sympathetic nerve activity (MSNA; microneurography, 11 paired recordings), and beat-to-beat blood pressure (BP; photoplethysmography) between trials (at both pre- and post-drug/placebo time points) using paired, two-tailed t-tests. Before drug/placebo administration, perceived pain (p=0.8287), Δ MSNA burst frequency (p=0.7587), and Δ mean BP (p=0.8649) during the CPT were not different between trials. After the drug/placebo administration, fentanyl attenuated perceived pain (36 vs. 66 mm, p<0.0001), Δ MSNA burst frequency (9 vs. 17 bursts/minute, p=0.0054), and Δ mean BP (7 vs. 13 mmHg, p=0.0174) during the CPT compared to placebo. Fentanyl-induced reductions in pain perception and Δ mean BP were moderately related (r=0.40, p=0.0641). These data provide valuable information regarding how low-dose fentanyl reduces autonomic cardiovascular responses during an experimental painful stimulus.


Author(s):  
Fabrizio Benedetti ◽  
Martina Amanzio ◽  
Fabio Giovannelli ◽  
Karen Craigs‐Brackhahn ◽  
Aziz Shaibani

2021 ◽  
Author(s):  
Alexandra Dumitrescu ◽  
Erin C Hanlon ◽  
Marilyn Arosema ◽  
Olga Duchon ◽  
Matthew Ettleson ◽  
...  

Background: Liothyronine (LT3) has been increasingly used in combination with levothyroxine (LT4) in the treatment of hypothyroidism. A metal coordinated form of LT3, known as poly-zinc-liothyronine (PZL), avoided in rats the typical T3 peak seen after oral administration of LT3. Objectives: To evaluate in healthy volunteers (i) the pharmacokinetics of PZL-derived T3 after a single dose, (ii) the pharmacodynamics of PZL-derived T3, (iii) monitoring for the adverse events; (iv) exploratory analysis of the sleep patterns after LT3, PZL or placebo administration. Methods: 12 healthy volunteers 18 to 50 years of age were recruited for a Phase 1, double-blind, randomized, single-dose placebo-controlled, cross-over study to compare PZL against LT3 or placebo. Subjects were admitted three separate times to receive a randomly assigned capsule containing placebo, 50-mcg LT3, or 50-mcg-PZL, and were observed for 48h. A 2-week wash-out period separated each admission. Results: LT3-derived serum T3 levels exhibited the expected profile, with a Tmax at 2h and return to basal levels by 24-36h. PZL-derived serum T3 levels exhibited a ~30% lower Cmax that was 1 h delayed and extended into a plateau that lasted up to 6h. This was followed by a lower but much longer plateau; by 24 hours serum T3 levels still exceeded 1/2 of Cmax. TSH levels were similarly reduced indistinguishably in both groups. Conclusion: PZL possesses the necessary properties to achieve a much improved T3 pharma-cokinetic. Drug product development of PZL should improve the delivery of T3 even further. PZL is on track to provide hypothyroid patients with stable levels of serum T3.


2021 ◽  
pp. 216770262110097
Author(s):  
Tao Liu

Placebo effects have increasingly aroused scientific and public interest for their clinical and research values. However, underlying mechanisms of this mind–body phenomenon are not yet fully understood. In this article, I propose a new model according to which context-based placebo effects source from positive treatment beliefs but are directly caused by benefit expectations. By virtue of mediating belief-expectation transformation, placebo administration triggers, and thus has a pivotal role in, subsequent therapeutic responses.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0249167
Author(s):  
Yasuki Ono ◽  
Tetsu Hirosawa ◽  
Chiaki Hasegawa ◽  
Takashi Ikeda ◽  
Kiwamu Kudo ◽  
...  

Watching another person’s hand movement modulates somatosensory evoked magnetic fields (SEFs). Assuming that the mirror neuron system may have a role in this phenomenon, oxytocin should enhance these effects. This single-blinded, placebo-controlled, crossover study therefore used magnetoencephalography (MEG) to investigate SEFs following electrical stimulation of the right median nerve in 20 healthy male participants during hand movement observation, which were initially presented as static images followed by moving images. The participants were randomly assigned to receive either oxytocin or saline during the first trial, with the treatment being reversed during a second trial. Log-transformed ratios of the N20 and N30 amplitudes were calculated and compared between moving and static images observations. Phase locking (calculated using intertrial phase coherence) of brain oscillations was also analyzed to evaluate alpha, beta and gamma rhythm changes after oxytocin administration. Log N30 ratios showed no significant changes after placebo administration but showed a decreasing tendency (albeit not significant) after placebo administration, which may suggest mirror neuron system involvement. In contrast, log N20 ratios were increased after placebo administration, but showed no significant change after oxytocin administration. Interestingly, the gamma band activity around N20 increased after placebo administration, suggesting that oxytocin exerted an analgesic effect on median nerve stimulation, and inhibited the gamma band increase. Oxytocin might therefore modulate not only the mirror neuron system, but also the sensory processing associated with median nerve stimulation.


2020 ◽  
Vol 21 (1) ◽  
Author(s):  
Dimos D. Mitsikostas ◽  
◽  
Charlotte Blease ◽  
Elisa Carlino ◽  
Luana Colloca ◽  
...  

Abstract Background and aim Despite recent publications, practitioners remain unfamiliar with the current terminology related to the placebo and nocebo phenomena observed in clinical trials and practice, nor with the factors that modulate them. To cover the gap, the European Headache Federation appointed a panel of experts to clarify the terms associated with the use of placebo in clinical trials. Methods The working group identified relevant questions and agreed upon recommendations. Because no data were required to answer the questions, the GRADE approach was not applicable, and thus only expert opinion was provided according to an amended Delphi method. The initial 12 topics for discussion were revised in the opinion of the majority of the panelists, and after a total of 6 rounds of negotiations, the final agreement is presented. Results/recommendations Two primary and mechanism-based recommendations are provided for the results of clinical trials: [1] to distinguish the placebo or nocebo response from the placebo or nocebo effect; and [2] for any favorable outcome observed after placebo administration, the term “placebo response” should be used, and for any unfavorable outcome recorded after placebo administration, the term “nocebo response” should be used (12 out of 17 panelists agreed, 70.6% agreement). The placebo or nocebo responses are attributed to a set of factors including those that are related to the medical condition (e.g. natural history, random comorbidities, etc.), along with idiosyncratic ones, in which the placebo or nocebo effects are attributed to idiosyncratic, or nonspecific mechanisms, exclusively (e.g. expectation, conditioning, observational learning etc.). To help investigators and practitioners, the panel summarized a list of environmental factors and idiosyncratic dynamics modulating placebo and nocebo effects. Some of them are modifiable, and investigators or physicians need to know about them in order to modify these factors appropriately to improve treatment. One secondary recommendation addresses the use of the terms “placebo” and “nocebo” (“placebos” and “nocebos” in plural), which refer to the triggers of the placebo/nocebo effects or responses, respectively, and which are inert agents or interventions that should not be confused with the placebo/nocebo responses or effects themselves (all panelists agreed, 100% agreement). Conclusion The working group recommends distinguishing the term response from effect to describe health changes from before to after placebo application and to distinguish the terms placebo(s) or nocebo(s) from the health consequences that they cause (placebo/nocebo responses or effects).


2020 ◽  
Vol 72 ◽  
pp. 138-143
Author(s):  
Sifan Hu ◽  
Jie Chen ◽  
Yuezhen Li ◽  
Yan Shao ◽  
Xiaoxia Zhao ◽  
...  

2020 ◽  
Author(s):  
Ortal Shimon-Raz ◽  
Roy Salomon ◽  
Miki Bloch ◽  
Gabi Aisenberg Romano ◽  
Talma Hendler ◽  
...  

AbstractReorganization of the maternal brain, primed by oxytocin surge during childbirth, triggers the species-typical maternal social behavior. These brief social moments carry profound effects on the infant’s social brain and likely have a distinct signature in the maternal brain. Utilizing a double-blind, oxytocin/placebo administration crossover design, we imaged mothers twice while observing three naturalistic maternal-infant contexts in the home ecology; “unavailable”, “unresponsive”, and “social”, when mothers engaged in synchronous pick-a-boo play. We found four processes by which mother’s brain registers social moments. Salience - social moments increased activations throughout the maternal brain network; Brain-behavior coupling - caregiving behavior linked with socially-driven neural response; Oxytocin sensitivity – administration impacted neural response mainly to the social context; and Temporal engrams–consistent temporal patterns in insula and TP characterized response to social play. Findings describe how mother’s brain compiles and amplifies these precious social moments to generate dyad-specific brain-behavior patterns that initiate the cross-generational transmission of human sociality.


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