The HALO Lab has been equipped through a CFI/ORF Leaders Opportunity Fund grant awarded to Dr. Adamo.
Metabolic System
CPX Ultima Metabolic Cart: The amount of energy generated by the body at rest or during exercise can be measured either by direct or indirect calorimetry. Although a human calorimeter can be used to directly measure heat production, and hence energy expenditure at rest or during exercise, such instrumentation is only available at the most sophisticated of laboratories and due to physical constraints usually limited to resting evaluations. For our purposes, indirect calorimetry based upon oxygen consumption is by far the method of choice with which to measure pediatric fitness as well as energy expenditure. The CPX Ultima metabolic cart by MedGraphics can measure energy expenditure in real time on a breath-by-breath basis and provides objective, reproducible data on functional capacity. Knowledge of metabolic rate is vital to nutritional assessment, weight loss planning and care of various medical conditions hence the rate at which oxygen is consumed and carbon dioxide is produced will be measured directly and the resting energy expenditure is calculated from the measured oxygen consumption and CO2 production. The relationship between oxygen consumed and calories burned is defined by the Wier equation 1,2. This system will also provide a measure of substrate oxidation as reflected in the respiratory quotient (RQ=CO2/O2). With a completely digital data acquisition and precise breath-by-breath analysis, the CPX Ultima sets the benchmark for gas exchange systems in the world today.
Corival Cycle Ergometer: The Corival Ergometer is an electronically braked cycle that is ideal for use in a wide range of individuals. This versatile ergometer interfaces directly with the MedGraphics CPX Ultima metabolic cart and enables the user to assess aerobic capacity using ramping or steady state protocols. The workload is continuously adjustable in a range of 7 to 1000 watts and the accuracy of this cycle ergometer is < 3%. This cycle is appropriate for our pediatric population in that there is a low step-through height allowing for effortless mounting tall for all users (children and adolescents). This ergometer includes a pediatric adaptation for smaller users and Zero-Watt start up. For use in very young children there is a pediatric kit including a small seat and adjustable cranks allowing for a minimum leg length of 610 mm and saddle height of 530 mm.
Trackmaster TMX425C Treadmill: The 425 Series treadmills interface directly with the MedGraphics CPX Ultima system. This particular treadmill is smooth, quiet and the most reliable on the market. The TMX425C treadmill is self-calibrating, virtually maintenance-free and it’s well-designed safety features including a low deck profile, smooth belt operation, low guide rails and an easy-to-reach emergency stop switch that will ensure the absolute safety and comfort of our pediatric population. The large 22″ x 63″ deck absorbs impact while providing plenty of room to run or walk and can accommodate users up to 400 lbs, which is a key consideration for our obese population.
Polar HR monitors: The Polar devices are the most well known and critically evaluated HR monitors in the fitness industry. These monitors, worn during the fitness testing, interface with the treadmill or bike system and will record heart rate continuously. Having a measure of HR during exercise at various speeds allow us not only to identify peak HR, but to also match HR with particular exercise intensities. This will permit us to give specific guidelines for exercise training and physical activity.
MedGraphics Pressure Perfect Blood Pressure System: This system is designed to automatically measure and display a patient’s systolic and diastolic pressures during treadmill and cycle ergometer fitness tests. The Pressure Perfect interfaces with the Metabolic cart to automatically and accurately measure blood pressure. The measures determined with this device are equivalent to those obtained by a trained observer using the cuff/stethoscope auscultation method. This system includes an onscreen message and audio alarm tone for user defined blood pressure ranges providing added safety.
How the metabolic system will be used…
This Metabolic System is critical to our planned research as calculating accurate energy requirements will guide diet intervention in obesity treatment approaches, and will allow us to assess precise changes in energy expenditure and aerobic fitness in individuals that occur over time or in response to intervention.
Cardiorespiratory Fitness ( O2peak)
Before testing, subjects will perform a 5-min warm-up on the treadmill or cycle ergometer (depending on the specific testing protocol) at a comfortable workload to prepare for maximal exercise. Subjects will perform a graded exercise test on the same device to determine their peak oxygen uptake ( O2peak). Peak VO2 is considered to be attained when at least one of the following criteria are met; i) an oxygen plateau (< 2ml/kg/min increase in VO2 with increasing work rate, ii) a respiratory exchange ratio > 1.0, or iii) HR > 200 beats/min. An exercise physiologist appropriately trained to evaluate children and adolescents undergoing exercise testing will perform this test.
Metabolic Measures
Metabolic measurements including O2, CO2, RER, and ventilation will be obtained continuously during this test using a metabolic cart. Subjects expire air through a two-way rebreathing valve, which is connected to the metabolic cart. The metabolic cart will be calibrated before each use using medical-grade gasses of known concentrations and a 3.0-L calibration syringe.
Heart Rate and Ratings of Perceived Exertion
Both these measures are obtained at the end of each 60-s period during the O2peak test. Heart rate is obtained via a Polar heart-rate monitor. Subjective ratings of exertion are obtained using Borg’s 6- to 20-point RPE scale.
BIO-SPECIMEN SAMPLING
Benchtop Eppendorf centrifuge
As part of our research program we collect biological samples for measuring various metabolites in serum, plasma or whole blood. Thus a centrifuge, capable of separating substances of differing densities, is thus an instrumental piece of equipment for our team. Depending on the biological specimen and separation requirements different rotor, speed, size and temperature capacities may be required from a centrifuge and for this reason we have a highly adaptive, space-saving, multipurpose refrigerated, swing-bucket centrifuge.
Ultralow temperature Freezer
To preserve the stability of the various biological markers to be analyzed, special care must be taken not only during sample collection, and processing, but storage as well. Ultra low temperature freezers are regularly used to provide the environment needed to stabilize these markers. Each type of marker requires a varying different length of storage time and often analyses cannot be done until a large quantity of samples have been collected.
We have a Thermo Scientific Revco PLUS Series Ultra-Low Temperature Freezer that combines refrigeration engineering expertise, safe storage, and temperature stability with a modern design that focuses on functionality, convenience, and ease of use. It provides safe storage at -50°C to -86°C with a microprocessor controller that maintains a constant temperature and can be set in 1°C increments. Audible/visual alarms (e.g. high/low temp, power fail, probe fail, door open, etc) ensure peace-of-mind monitoring. Acoustical mufflers and sound-absorbing foam in the base of the uprights reduces noise, resulting in more comfortable working conditions in the lab.
Pipettes
– Standard Manual Pipette Set (3) & Electronic multi-channel pipettes (2)
Multimodal Plate reader & Plate shaker
For studies that entail biochemical assays (ELISA, EIA) that require a plate reader, our lab is equipped with a Beckman Coulter DTX 800 detector. This enables multiple detection modes, including fluorescence, luminescence and absorbance in a single reader. A plate shaker is also available that complements the plate reader.
Sample storage and tracking system
As our capacity grows we will be storing and accessing samples from multiple studies, and thus we have accrued the FreezerWorks Bar Code System and software package for bio-specimen labeling and tracking.
Body Composition Analyses
GE Lunar Prodigy ADVANCE: Dual Energy Xray Absorptiometry Analyses (DEXA):
DEXA is rapidly becoming the clinical method of choice for body composition analyses because of it’s low dose, speed, ease of application, and superior reproducibility. Other non-invasive methods estimate tissue characteristics based on variables that are indirect indicators (potassium concentration, water content). Even underwater weighing assumes that bone mass is a constant proportion of lean mass and that tissue hydration is constant. The Body Composition feature of the GE Lunar Prodigy ADVANCE provides direct calculation of total fat, lean and bone tissue and the lowest radiation dose on the market. Additional measurements that only GE Lunar offers are measures of android and gynoid regions, comparison with World Health Organization (WHO) Body Mass Index (BMI) graphs, and reference data for total % fat. Total Body results are calculated automatically for BMD, fat issue, and lean tissue for the total body & sub-regions. Customized regions of interest also can be analyzed for BMD and body composition. Importantly, the Prodigy ADVANCE is twice as fast as other densitometers and has the lowest radiation exposure on the market thereby improving patient comfort and safety, which is of particular importance in the pediatric population. The GE Lunar Prodigy ADVANCE includes gender-specific pediatric reference data as well as an option for measuring total body composition in young children and infants.
Because accurate measures of body composition are of paramount importance for evaluating response to treatment intervention or changes over time in fat distribution, our DEXA’s low dose (0.4 μGy), rapid speed (<5 min/scan), ease of application (no need for lead shielding or radiology specialist to operate) and superior reproducibility (CV=1%), is a central component of our laboratory infrastructure.
Infant Skin fold calipers
We have expanded our research streams and established collaborative relationships with other specialists, one of which will allow us to look at obesity development trajectories in infants. For this reason our infrastructure also includes a set of skin-fold calipers which are needed for body composition measurement in infants for whom the DEXA scanner measures are not appropriate.
Dietary Analyses Software
Our lab infrastructure includes the dietary analyses package: FoodProcessor SQL, a comprehensive, up-to-date and user-friendly dietary analysis software package that includes Canadian nutrient intake values.
Physical Activity Monitoring
Actical® Physical Activity Monitor: While PA can be measured by questionnaires, this approach relies on the ability of the subject (or parent) to recall activity accurately and the literature suggests that children are able to recall only 50% of the previous week’s PA 3. It is also difficult to translate qualitative information (played for ½ hour) on PA to quantitative data (i.e. kcal consumed), as there is limited information available on the specific energy costs of different activities in children. To solve these problems we intend to measure PA by portable accelerometry. Accelerometry is based on the relationship between muscular force and body acceleration during physical movement. The Actical multidirectional, piezoelectric accelerometer is sensitive to 0.05g. The Actical device is warn around the waist and the degree and intensity of motion acting upon the sensor produces a variable voltage output signal and digital integration data acquisition incorporates intensity of movement into a total activity count. The Actical software will produce data on: i) average energy expenditure (kcals per minute), total activity (counts), average activity (counts per minute), Time Interval Duration (minutes), total energy expenditure within each activity range (kcals) sedentary, light, moderate, and vigorous activity ranges, average energy expenditure within each activity range (kcals per minute), accumulated time within each activity range (minutes), ratio of accumulated time within each activity range to total time (%), active energy expenditure (AEE) and metabolic equivalent (MET). Actical’s activity count data is converted into minute-by-minute energy expenditure. This is used to calculate daily, hourly, and custom interval caloric consumption. Algorithms are based on carefully validated studies in which a wide range of subjects 4,5, including children ages 3-5 6, performed a variety of physical tasks.
The Actical device is worn around the waist and held in place by the specifically designed waistband. In order to download the data gathered by the Actical accelerometer an Actireader- interface and cable system are also available.
Actiwatch®: similar to the Actical the Actiwatch® is a small accelerometer device that uses actigraphy principles to provide sleep schedule variability, sleep quantity and quality statistics and daytime activity patterns so you can better identify therapeutic options and understand responses to treatment for patients. One of our research interests relates the role that maternal obesity and gestation weight gain plays in programming downstream infant and child obesity. It is therefore necessary for us to assess self-generated & spontaneous movement in infants post delivery. These measurements will be made by placing an Actiwatch®, that records a digitally integrated measure of gross motor activity via accelerometry, on the right ankle using an ankle band and another just above the iliac crest on the infants’ right side. 24-h activity data will be analyzed to determine the separation of moderate-to-vigorous activity and sedentary-to-light activity, the classification of sleep and wake state for each data point, and the transition points from day to night and night to day.