Exploring an Impaired Sphingosine-1-Phosphate Response to Skeletal Muscle Damage in a Murine Model of Type 1 Diabetes Mellitus

Skeletal muscle is an adaptive tissue that possesses an innate ability to fully regenerate from a damaging stimulus. Type 1 diabetes mellitus (T1DM) elicits a pathophysiological environment that prevents normal skeletal muscle regeneration by dysregulating key events in the regenerative process. It has been shown that the sphingosine-1-phosphate (S1P) response to skeletal muscle damage is blunted in murine models of T1DM. S1P content normally increases in skeletal muscle acutely (within seven days) following damage to promote regeneration, and an absence of this response results in inadequate recovery. Thus, the lack of S1P accumulation seen in skeletal muscle of diabetic rodents following damage has the potential to contribute to impaired muscle regeneration. This investigation aimed to elucidate the mechanisms underlying this response by assessing: 1) S1P content via Liquid-Chromatography Mass-Spectrometry and 2) expression level of proteins that regulate S1P content via SDS-PAGE and Western Blot analysis. Results from this study show a blunted S1P response to skeletal muscle damage in a T1DM model as S1P content is reduced in Akita mice five days into regeneration. Furthermore, it was found that while sphingosine lyase (SPL) expression increased in both the T1DM models and WT mice following muscle damage, this expression was significantly greater in the diabetic condition. Total sphingosine kinase 1 content was also found to be increased five days following damage, but there was no significant effect of diabetes. Thus, the greater expression of SPL in the T1DM model suggests that S1P is degraded at a faster rate, preventing the normal accumulation of S1P following skeletal muscle damage. Future research should aim to identify the cause of this overexpression and the impact it has on skeletal muscle regeneration

Economics methods in Cochrane systematic reviews of health promotion and public health related interventions.

Peer reviewedPublisher PD

Anthropometric Normative-Reference Standards For Canadian University-Aged Students

ANTHROPOMETRIC NORMATIVE-REFERENCE STANDARDS FOR CANADIAN UNIVERSITY-AGED STUDENTS Jordan Deneau1, Michael Mallender1, Paula van Wyk1, Adriana Duquette1, 1Department of Kinesiology, University of Windsor, Windsor, ON Structural anthropometric measurements are based on the standard fixed postures of the human body and are used by ergonomists to design products and environments that accommodate the unique physical constraints of their users [1]. As a result of variability among demographics, it is important that anthropometric normative-reference standards are current [2] and specific to the population they describe [3]. Therefore, the purpose of this investigation was to create current anthropometric normative-reference standards for a young Canadian adult population. Thirty-six structural body dimensions were manually measured on 279 Canadian university-aged participants (150 male, 129 female). All measurements were taken on the right side of the participants’ body for standardization, and two measurements were taken for each body dimension in a circuit/rotational order to reduce the potential for error. If there was a discrepancy greater than 25mm between the two measurements, a third measurement was taken; and the average of the two closest measurements was recorded. All participants consented to the collection of their anthropometric data as part of a university laboratory based course. A variety of demographic statistics were calculated. As an example, anthropometric measure percentiles were determined for Stature (M: 5th%ile 1668.65mm; 50th%ile 1782.00mm; 95th%ile 1892.58mm F: 5th%ile 1546.25mm; 50th%ile 1640.00mm; 95th%ile 1759.50mm), Sitting Height (M: 5th%ile 845.50mm; 50th%ile 931.25mm; 95th%ile 1282.75mm F: 5th%ile 793.50mm; 50th%ile 870.00mm; 95th%ile 935.24mm), and Hip Breadth (M: 5th%ile 295.50mm; 50th%ile 363.75mm; 95th%ile 440.00mm F: 5th%ile 281.75mm; 50th%ile 358.00mm; 95th%ile 456.50mm). Few studies have reported current Canadian anthropometric normative-reference standards in young adults. The authors are unaware of any Canadian studies that have measured as many as 36 body dimensions on a significant sample size. Thus, the reported anthropometric data can be used as a relevant consideration in Canadian product and environment design. References [1] Pheasant, S. (1996). Bodyspace: Anthropometry, ergonomics, and the design of work. United Kingdom: Taylor & Francis. [2] Pagano, B. T., Parkinson, M. B., & Reed, M. P. (2015). An updated estimate of the body dimensions of US children. Ergonomics, 58(6), 1045-1057. [3] Behara, D. N., & Das, B. (2010). Structural anthropometric measurements of the Canadian adult population: the fallacy of the \u27average person\u27 concept. Theoretical Issues in Ergonomics Science, 13(3), 380-392

Determining Normative Gait Patterns in a Healthy University-Aged Canadian Population Utilizing the GAITRite® System.

Human gait can consist of both the walking and running aspects of the human locomotion pattern and may be analyzed from a kinetic and/or kinematic focus (Hamil & Knutzen, 2009). Abnormal gait patterns often arise in part due to physical declines resulting from an injury, the aging process (Owings & Grabiner, 2004), or due to neurological disorders such as Parkinson’s and Huntington’s disease (Hausdorff et al, 1998). In order to compare gait throughout the lifespan, or throughout a rehabilitation process, it is important to determine the standards of a healthy population. The aim of this investigation was to establish the normative standards of specific temporal and spatial characteristics of gait in a healthy university-aged Canadian population. Twenty temporal measures and eleven spatial measures of gait were collected using the GAITRite® system (CIR Systems, Inc., New York, USA). Using a standardized protocol, participants (n=225; 127 male, 98 female) were instructed to begin walking approximately two meters behind where the GAITRite® system pressure sensor embedded mat was located on the floor, and to walk across the mat using their normal gait pattern at their preferred pace. All participants were Canadian university-aged adults and consented to the data collection and analysis as part of a kinesiology laboratory based course. Descriptive statistics, reported by sex, were analyzed on twenty temporal measures [e.g. Mean Step Time Left (M= 0.56s, F= 0.52s), Mean Cycle Time Left (M= 1.11s, F= 1.02s)] and eleven spatial measures [e.g. Mean Step Length Left (M= 82.55 cm, F= 77.26 cm), Mean Heel to Heel base of support Left (M= 10.74 cm, F= 9.16 cm)]. The literature lacks an extensive analysis of temporal and spatial gait characteristics for a young, healthy Canadian population during unaltered conditions; which the results of this study can now provide. Future research and rehabilitation programs can apply these results when comparing to data collected in clinical and laboratory settings. References Hamill J, & Knutzen KM. Biomechanical Basis of Human Movement. 3rd. Philadelphia: Lippincott, Williams & Wilkins; 2009. Hausdorff J, Cudkowicz M, Firton R, Wei J, & Goldberger A. (1998). Gait variability and basal ganglia disorders: Stride to Stride Variations of gait cycle timing in Parkinson’s disease and Huntington’s disease. Movement Disorders, 13(3), 428-437. Owings T, & Grabiner M. (2004). Variability of step kinematics in young and older adults. Gait & Posture, 20(1), 26-35