Facilitators and barriers to enhancing physical activity in older patients during acute hospital stay:a systematic review

Background To improve older patients' physical activity (PA) behavior, it is important to identify facilitators and barriers to enhancing PA in older patients (>= 65 years) during hospitalization from the perspectives of patients, caregivers, and healthcare professionals (HCPs). Methods In this systematic review, a search of PubMed, CINAHL, PsycINFO, EMBASE, and Web of Science (January 2000-May 2021) was performed, and quantitative, qualitative, and mixed-methods studies were included. The methodological quality of included studies was assessed using the Mixed Methods Appraisal Tool. Identified facilitators and barriers were categorized using the social ecological model at the intrapersonal, interpersonal, and institutional levels. Results The 48 included articles identified 230 facilitators and 342 barriers. The main facilitators at the intrapersonal level included: knowledge, awareness, and attitudes; interpersonal level: social support, including encouragement and interdisciplinary collaboration; and institutional level: stimulating physical environment, patient activities and schedules, and PA protocols. The main barriers at the intrapersonal level included: physical health status, having lines or drains, patients' fear, and HCPs' safety concerns; interpersonal level: patient-HCP relation and HCPs' unclear roles; and institutional level: lack of space and resources, including time and equipment. Best evidence synthesis provided moderate level of evidence for three barriers: patients' unwillingness or refusal to move, patients having symptoms, and patients having lines or drains. No moderate level of evidence was found for facilitators. Conclusion The PA behavior of older adults during hospitalization is multidimensional. Our overview highlights facilitators and barriers on multilevel scale (intrapersonal, interpersonal, and institutional levels) that guides patients, caregivers, HCPs, and researchers in future clinical practice, and intervention development and implementation

Binding of Pramipexole to Extrastriatal Dopamine D2/D3 Receptors in the Human Brain: A Positron Emission Tomography Study Using 11C-FLB 457

The purpose of this study was to determine the binding sites of pramipexole in extrastriatal dopaminergic regions because its antidepressive effects have been speculated to occur by activating the dopamine D2 receptor subfamily in extrastriatal areas. Dynamic positron emission tomography (PET) scanning using 11C-FLB 457 for quantification of D2/D3 receptor subtype was performed on 15 healthy volunteers. Each subject underwent two PET scans before and after receiving a single dose of pramipexole (0, 0.125, or 0.25 mg). The study demonstrated that pramipexole significantly binds to D2/D3 receptors in the prefrontal cortex, amygdala, and medial and lateral thalamus at a dose of 0.25 mg. These regions have been indicated to have some relation to depression and may be part of the target sites where pramipexole exerts its antidepressive effects

Discovery of a Novel Muscarinic Receptor PET Radioligand with Rapid Kinetics in the Monkey Brain

Positron emission tomography (PET), together with a suitable radioligand, is one of the more prominent methods for measuring changes in synaptic neurotransmitter concentrations in vivo. The radioligand of choice for such measurements on the cholinergic system is the muscarinic receptor antagonist <i>N</i>-[1-¹¹C]­propyl-3-piperidyl benzilate (PPB). In an effort to overcome the shortcomings with the technically cumbersome synthesis of [¹¹C]­PPB, we designed and synthesized four structurally related analogues of PPB, of which (<i>S</i>,<i>R</i>)-1-methylpiperidin-3-yl)­2-cyclopentyl-2-hydroxy-2-phenylacetate (<b>1</b>) was found to bind muscarinic receptors with similar affinity as PPB (3.5 vs 7.9 nM, respectively). (<i>S</i>,<i>R</i>)<b>-1</b> was radiolabeled via <i>N</i>-¹¹C-methylation at high radiochemical purity (>99%) and high specific radioactivity (>130 GBq/μmol). In vitro studies by autoradiography on human brain tissue and in vivo studies by PET in nonhuman primates demonstrated excellent signal-to-noise ratios and a kinetic profile in brain comparable to that of [¹¹C]­PBB. (<i>S</i>,<i>R</i>)-[¹¹C]<b>1</b> is a promising candidate for measuring changes in endogenous acetylcholine concentrations