National estimates of self-reported sitting time in adults with multiple sclerosis.

BACKGROUND: Limited data exist on the prevalence and distribution of sedentary behavior (SB) in multiple sclerosis (MS). OBJECTIVE: The objective of this paper is to describe sitting time as a metric of SB in a large national sample of people with MS. METHODS: A total of 8004 individuals from the North American Research Committee on MS (NARCOMS) Registry completed the sitting time question from the International Physical Activity Questionnaire in spring 2015. We present descriptive data on sitting time for the total sample and across sociodemographic, clinical, and behavioral characteristics. RESULTS: The final sample included 6483 individuals. Of these, 36.7% were classified with mild disability, 24.7% with moderate disability, and 38.6% with severe disability. Median sitting time for the total sample was 480 min/day (P25 = 310 min/day, P75 = 720 min/day). Sitting time was highest for individuals with MS who were male (540 min/day), not married (540 min/day), had a disease duration >30 years (540 min/day), were underweight (540.5 min/day), had an annual income of < $15,000 (585 min/day), presented with a progressive form of MS (600 min/day), were classified as insufficiently active (600 min/day), or presented with severe disability (661 min/day). CONCLUSION: Sitting time is twice as high in individuals with MS compared to the general population (240 min/day).

Calibrating a novel multi-sensor physical activity measurement system.

Advancing the field of physical activity (PA) monitoring requires the development of innovative multi-sensor measurement systems that are feasible in the free-living environment. The use of novel analytical techniques to combine and process these multiple sensor signals is equally important. This paper describes a novel multi-sensor 'integrated PA measurement system' (IMS), the lab-based methodology used to calibrate the IMS, techniques used to predict multiple variables from the sensor signals, and proposes design changes to improve the feasibility of deploying the IMS in the free-living environment. The IMS consists of hip and wrist acceleration sensors, two piezoelectric respiration sensors on the torso, and an ultraviolet radiation sensor to obtain contextual information (indoors versus outdoors) of PA. During lab-based calibration of the IMS, data were collected on participants performing a PA routine consisting of seven different ambulatory and free-living activities while wearing a portable metabolic unit (criterion measure) and the IMS. Data analyses on the first 50 adult participants are presented. These analyses were used to determine if the IMS can be used to predict the variables of interest. Finally, physical modifications for the IMS that could enhance the feasibility of free-living use are proposed and refinement of the prediction techniques is discussed.

The discriminative stimulus effects of methamphetamine in pigeons.

This experiment was designed to elucidate the neurotransmitter systems that mediate the discriminative stimulus effects of methamphetamine. Four pigeons were trained to peck one key following saline injections and a second key following methamphetamine injections (1.0 or 1.7 mg/kg, IM). Substitution tests revealed drug-appropriate responding following administration of the psychomotor stimulants methamphetamine, amphetamine and cocaine, the dopamine (DA) reuptake inhibitor bupropion, norepinephrine (NE) reuptake inhibitors imipramine and tomoxetine, and the serotonin (5-HT) releaser fenfluramine. Saline-key responding occurred following administration of the D1 agonist SKF-38393, the D1 antagonist SCH-23390, the alpha 2 receptor agonist clonidine, the alpha 1 antagonist prazosin, a nonselective beta-antagonist propranolol and the selective 5-HT reuptake inhibitor fluoxetine. The D2/D3 agonist quinpirole produced drug-appropriate responding in two pigeons and partial substitution in the remaining two pigeons. The 5HT1A agonist 8-OH-DPAT produced drug-appropriate responding at higher doses (0.3-1.0 mg/kg), whereas much lower doses (0.003-1.0 mg/kg) antagonized the methamphetamine stimulus. The stimulus effects of methamphetamine were attenuated by pretreatment with prazosin, SCH-23390 and eticlopride, whereas pretreatment with propranolol and the 5-HT3 antagonist, MDL 72222, failed reliably to attenuate drug key responding. These results suggest that NE and DA reuptake inhibition and 5-HT release mediate the discriminative stimulus effects of methamphetamine as do the 5-HT1A and DA D1 and D2 receptors.