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Biomedical subjects

Richard Simpson

Publications and source records attributed to Richard Simpson.

9 recordsLinked to original sources
PubMed2007

Impact of repeated prolonged exercise bouts on cardiac function and biomarkers.

PURPOSE: The present study examined the impact of repeated bouts of prolonged (< 60 min) exercise on left ventricular function and cardiac biomarkers. METHODS: Ten athletes completed a 15.3-mile hill run on three consecutive days and were assessed before, immediately after, 1 h after, and 20 h after each bout. Six of the athletes completed a fourth bout. Left ventricular (LV) function was examined echocardiographically using two-dimensional M-mode, Doppler, and flow propagation velocity (Vp). Venous blood samples were analyzed for cardiac biomarkers including cardiac troponin T (cTnT). RESULTS: Ejection fraction (EF) significantly decreased (P = 0.027) after the third exercise bout compared with baseline (mean +/- SD: 56.3 +/- 4.4 vs 51.3 +/- 5.9%), accompanied by a nonsignificant decrease in systolic blood pressure/end systolic volume (SBP/ESV) ratio. A sustained depression in systolic function 20 h after bout 3 also persisted in the subset who completed a fourth bout, yet this did not reach clinical levels. Significant (P < 0.01) reductions in early to late diastolic filling (E:A) ratio pre-to post-bout 1 (mean +/- SD: 1.9 +/- 0.5 vs 1.4 +/- 0.3) and pre- to post-bout 3(2.0 +/- 0.5 vs 1.3 +/- 0.4) normalized after each 20-h recovery period. A similar pattern of change was observed in Vp. Cardiac troponin T was elevated in four individuals 1 h after bout 1 (range: 0.013-0.125 microg.L(-1)) but was undetectable thereafter except in one athlete. CONCLUSION: Repeated bouts of prolonged exercise induce short-term reductions in diastolic filling and a cumulative decrease in systolic function, yet these alterations seem to have minimal clinical or functional impact. Elevated cTnT after the initial bout, but not thereafter, may represent an adaptive response to prolonged exercise.

Adult↗
PubMed2005

A prototype power assist wheelchair that provides for obstacle detection and avoidance for those with visual impairments.

BACKGROUND: Almost 10% of all individuals who are legally blind also have a mobility impairment. The majority of these individuals are dependent on others for mobility. The Smart Power Assistance Module (SPAM) for manual wheelchairs is being developed to provide independent mobility for this population. METHODS: A prototype of the SPAM has been developed using Yamaha JWII power assist hubs, sonar and infrared rangefinders, and a microprocessor. The prototype limits the user to moving straight forward, straight backward, or turning in place, and increases the resistance of the wheels based on the proximity of obstacles. The result is haptic feedback to the user regarding the environment surrounding the wheelchair. RESULTS: The prototype has been evaluated with four blindfolded able-bodied users and one individual who is blind but not mobility impaired. For all individuals, the prototype reduced the number of collisions on a simple navigation task. CONCLUSION: The prototype demonstrates the feasibility of providing navigation assistance to manual wheelchair users, but several shortcomings of the system were identified to be addressed in a second generation prototype.

Journal Article↗
PubMed2005

N-terminal isotope tagging with propionic anhydride: proteomic analysis of myogenic differentiation of C2C12 cells.

N-Terminal isotope tagging (NIT) is an important proteomic tool for quantifying proteins in complex mixtures. Here we describe a modified version of the isotope-coded propionylation procedure of Zhang et al. [Zhang et al., Rapid Commun. Mass Spectom. 16 (2002) 2325], which uses 'light' D0 and 'heavy' D10-propionic anhydride. The method has been extensively modified to improve both the kinetics and overall yield of propionylation. Using albumin as a model protein, the overall variation in quantification yields, calculated using several tryptic peptides, was within +/-10% (S.D. +/-0.2) error. The efficacy of the method is demonstrated by the quantitative differences obtained for vimentin in cell lysates of C2C12 myoblasts upon their myogensis to myotubules.

Amino Acid Sequence↗
PubMed2005

Virtual reality and computer-enhanced training applied to wheeled mobility: an overview of work in Pittsburgh.

Some aspects of assistive technology can be enhanced by the application of virtual reality. Although virtual simulation offers a range of new possibilities, learning to navigate in a virtual environment is not equivalent to learning to navigate in the real world. Therefore, virtual reality simulation is advocated as a useful preparation for assessment and training within the physical environment. We are engaged in several efforts to develop virtual environments and devices for mobility skills assessment and training, exercise training, and environment assessment. Virtual reality offers wheelchair users a training tool in different risk-free environments without any indoor (e.g., walls, furniture, and stairs) and outdoor (e.g., curb cuts, uneven terrain, and street traffic) physical constraints. Virtual reality technology will probably become more common in the field of assistive technology, especially given the rapid expansion of gaming technology and the continued exponential growth of computing power.

Computer Simulation↗
PubMed2004

Effects of QD insulin detemir or neutral protamine Hagedorn on blood glucose control in patients with type I diabetes mellitus using a basal-bolus regimen.

OBJECTIVE: The purpose of this trial was to compare the effects of QD basal insulin replacement using insulin detemir versus neutral protamine Hagedorn (NPH) insulin in basal-bolus therapy in combination with regular human insulin (HI) in patients with type 1 diabetes mellitus (DM). METHODS: This was a 6-month, prospective, randomized, open-label, controlled, parallel-group trial conducted at 92 sites in Europe and Australia. The trial population included men and women with type 1 DM for at least 1 year aged > or = 18 years with glycosylated hemoglobin (HbA(1c)) <== 12% already taking QD basal-bolus treatment with an intermediate- or long-acting insulin and a fast-acting human insulin or insulin analogue as bolus insulin. Patients were randomly assigned (2:1) to 6 months of treatment with insulin detemir or NPH at bedtime in combination with HI with main meals. Main outcome measures were blood glucose control as assessed by HbA(1c), fasting plasma glucose (FPG), 9-point self-monitored blood glucose (SMBG) profiles, 24-hour continuous blood glucose profiles, hypoglycemia, weight gain, and adverse events. RESULTS: Of the 749 patients randomized to treatment, 747 were exposed to trial products and included in the intent-to-treat analysis set. Seven hundred patients completed the trial: 465 (94.7%) in the insulin detemir group and 235 (91.8%) in the NPH group. After 6 months, FPG was lower with insulin detemir than with NPH (-1.16 mmol/L difference; P = 0.001), whereas HbA(1c) did not differ significantly between treatments (-0.12% [95% CI, -0.25 to 0.02]; P = NS). Day-to-day variability in self-measured fasting blood glucose was lower with insulin detemir (SD, 2.82 vs 3.60 mmol/L; P < 0.001). The overall shape of the 9-point SMBG profiles differed significantly between treatments (P = 0.006), with lower glucose levels before breakfast with insulin detemir than with NPH (P < 0.001). There was a 26% reduction in the relative risk of nocturnal hypoglycemia with insulin detemir compared with NPH (P = 0.003). Gain in body weight was significantly lower after 6 months with insulin detemir than with NPH (-0.54 kg difference; P = 0.024). The frequency and type of adverse events were similar between treatment groups. CONCLUSIONS: In this study, QD administration of insulin detemir at bedtime resulted in lower fasting blood glucose levels with less day-to-day variability and less fluctuation from ean blood glucose levels over 24 hours than NPH insulin, combined with an overall reduction in the risk of nocturnal hypoglycemia. These findings suggest that evening administration of insulin detemir may provide an opportunity to further improve fasting blood glucose targets.

Adult↗
PubMed2004

The development and preliminary evaluation of a decision aid based on decision analysis for two treatment conditions: benign prostatic hyperplasia and hypertension.

This paper discusses the development and evaluation of a computerised decision aid that provides individualised information about Benign Prostatic Hyperplasia (BPH) and Hypertension to patients. The program is based on decision analysis, using decision trees as a way of providing users with information regarding the probability of different outcomes occurring, obtaining an individual evaluation of the different outcomes, before providing guidance on what might be the 'best' option for that patient. It is intended that the program can be used as the basis for helping patients to become more involved in decisions about their medical treatment. Eight health care professionals and 19 patients (9 with BPH and 10 with Hypertension) evaluated the program. Overall it was assessed positively by both health care professionals and patients. However, before it can be integrated into health care practice, the program is to be evaluated further in a randomised trial.

Aged↗
PubMed2004

A common open representation of mass spectrometry data and its application to proteomics research.

A broad range of mass spectrometers are used in mass spectrometry (MS)-based proteomics research. Each type of instrument possesses a unique design, data system and performance specifications, resulting in strengths and weaknesses for different types of experiments. Unfortunately, the native binary data formats produced by each type of mass spectrometer also differ and are usually proprietary. The diverse, nontransparent nature of the data structure complicates the integration of new instruments into preexisting infrastructure, impedes the analysis, exchange, comparison and publication of results from different experiments and laboratories, and prevents the bioinformatics community from accessing data sets required for software development. Here, we introduce the 'mzXML' format, an open, generic XML (extensible markup language) representation of MS data. We have also developed an accompanying suite of supporting programs. We expect that this format will facilitate data management, interpretation and dissemination in proteomics research.

Database Management Systems↗
PubMed2004

The smart wheelchair component system.

While the needs of many individuals with disabilities can be satisfied with power wheelchairs, some members of the disabled community find it difficult or impossible to operate a standard power wheelchair. To accommodate this population, several researchers have used technologies originally developed for mobile robots to create "smart wheelchairs" that reduce the physical, perceptual, and cognitive skills necessary to operate a power wheelchair. We are developing a Smart Wheelchair Component System (SWCS) that can be added to a variety of commercial power wheelchairs with minimal modification. This paper describes the design of a prototype of the SWCS, which has been evaluated on wheelchairs from four different manufacturers.

Electric Power Supplies↗