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D Keast

Publications and source records attributed to D Keast.

At least 19 recordsLinked to original sources
PubMed2006

Monitoring 6 weeks of progressive endurance training with plasma glutamine.

The distinction between positive and negative training adaptation is an important prerequisite in the identification of any marker for monitoring training in athletes. To investigate the glutamine responses to progressive endurance training, twenty healthy males were randomly assigned to a training group or a non-exercising control group. The training group performed a progressive (3 to 6 x 90 minute sessions per week at 70 % V.O (2max)) six-week endurance training programme on a cycle ergometer, while the control group did not participate in any exercise during this period. Performance assessments (V.O (2max) and time to exhaustion) and resting blood samples (for haemoglobin concentration, haematocrit, cortisol, ferritin, creatine kinase, glutamine, uric acid and urea analysis) were obtained prior to the commencement of training (Pre) and at the end of week 2, week 4 and week 6. The training group showed significant improvements in time to exhaustion (p < 0.01), and V.O (2max) (p < 0.05) at all time points (except week 2 for V.O (2max)), while the control group performance measures did not change. In the training group, haemoglobin concentration and haematocrit were significantly lower (p < 0.01) than pretraining values at week 2 and 4, as percentage changes in plasma volume indicated a significant (p < 0.01) haemodilution (+ 6 - 9 %) was present at week 2, 4 and 6. No changes were seen in the control group. In the training group, plasma glutamine (week 2, 4 and 6), creatine kinase (week 2 and 4), uric acid (week 2 and 4) and urea (week 2 and 4) all increased significantly from pretraining levels. No changes in cortisol or ferritin were found in the training group and no changes in any blood variables were present in the control group. Plasma glutamine was the only blood variable to remain significantly above pretraining (966 +/- 32 micromol . 1 (-1)) levels at week 6 (1176 +/- 24 micromol . 1 (-1); p < 0.05) The elevation seen here in glutamine levels, after 6 weeks of progressive endurance training, is in contrast to previous reports of decreased glutamine concentrations in overtrained athletes. In conclusion, 6 weeks of progressive endurance training steadily increased plasma glutamine levels, which may prove useful in the monitoring of training responses.

Adult↗
PubMed2004

Educational intervention in the management of acute procedure-related wound pain: a pilot study.

OBJECTIVE: This report describes the pilot testing of an educational intervention to manage acute pain associated with wound care in an outpatient clinic. The intervention included essential elements of pain education identified in the acute pain literature: provision of information; pain measurement; establishing expectations; treatment planning; teaching environment. METHOD: The intervention was tested on five patients attending a wound clinic for scheduled treatment. Patients were aged 65 years or older and had a history of experiencing pain during treatment procedures such as dressing changes and debridement. Before the intervention, the study nurse gave the patients information about the procedure, discussed strategies they could use to make it as comfortable as possible, and explained how they could use a rating scale to denote any physical and emotional distress. RESULTS: All patients used the intervention strategies. Three out of five reported reduced pain and/or distress following the intervention. CONCLUSION: The pilot study supported the use of education as a pain control strategy in wound care and illuminated key methodological issues for further research on this topic.

Aged↗
PubMed2000

Is respite care available for chronically ill seniors?

OBJECTIVE: To determine family physicians' perceptions of how available respite care is and how easy it is to refer chronically ill older people to it, and to examine their opinions of respite care. DESIGN: Mailed survey to family physicians on the Thames Valley Family Practice Research Unit's mailing list. SETTING: London, Ont, and surrounding area. PARTICIPANTS: Of the 448 surveys mailed to eligible physicians, 288 were completed and returned for a response rate of 64.3%. MAIN OUTCOME MEASURES: Respondents' perceptions of how available respite care is and how easy it is to refer chronically ill older people to it and their opinions on the effectiveness of respite care. RESULTS: More than half the respondents reported that outpatient respite care is always available, but how available depended on practice location. Inpatient respite care was reported as less available. More than half the respondents found referral to respite care difficult. Respondents were very positive about the role of respite services in long-term care and in lowering caregiver stress. Respondents' perceptions varied according to where they had attended medical school. Their perceptions of respite care's role in long-term care and in helping patients remain at home were influenced by whether they thought respite care was available. CONCLUSION: Family physicians need education in the value of respite services for their chronically ill older patients and their families. Physicians also need information on the respite services available and strategies for accessing them. Our findings suggest a need for greater attention to regional discrepancies in availability of services.

Aged↗
PubMed2000

Preparing the wound bed--debridement, bacterial balance, and moisture balance.

Successful diagnosis and treatment of patients with chronic wounds involve holistic care and a team approach. The integration of the work of an interdisciplinary care team that includes doctors, nurses, and allied health professionals with the patient, family, significant others, and caregivers offers an optimal formula for achieving wound resolution. Such an approach challenges practitioners and everyone participating in wound care to integrate data and information that arise from a number of sources and mitigating factors. In this article, the authors define the changing paradigm that links treatment of the cause and focuses on three components of local wound care: debridement, wound-friendly moist interactive dressings, and bacterial balance. The authors demonstrate that the treatment of chronic wounds can be accomplished through a series of recommendations and rationales based on the literature and their experience. These recommendations lay the groundwork for thorough assessment and evaluation of the wound.

Algorithms↗
PubMed2000

Best practices for the prevention and treatment of pressure ulcers.

In this article, the Canadian Association of Wound Care puts forward 12 recommendations for best practices in the prevention and treatment of pressure ulcers that focus on an interdisciplinary patient-centered approach. These recommendations are a synthesis of the Agency for Health Care Policy and Research guidelines, European guidelines, and current literature as interpreted by the Canadian experience and achieved through a national consensus panel. The article concludes that best practice guidelines must be fluid documents that respond to new evidence and experience.

Bacterial Infections↗
PubMed1998

The case history of an elite ultra-endurance cyclist who developed chronic fatigue syndrome.

An elite ultra-endurance athlete, who had previously undergone physiological and performance testing, developed chronic fatigue syndrome (CFS). An incremental cycling exercise test conducted while he was suffering from CFS indicated decreases in maximum workload achieved (Wmax; -11.3%), the maximum oxygen uptake (VO2max; -12.5%), and the anaerobic threshold (AT; -14.3%) compared to pre-CFS data. A third test conducted after the athlete had shown indications of significant improvement in his clinical condition revealed further decreases in Wmax (-7.9%), VO2max (-10.2%) and AT (-8.3%). These data, along with submaximal exercise data and muscle biopsy electron microscopic analyses, suggest that the performance decrements were the result of detraining, rather than an impairment of aerobic metabolism due to CFS per se. These data may be indicative of central, possibly neurological, factors influencing fatigue perception in CFS sufferers.

Adult↗
PubMed1998

A simple bacterial bioassay for the measurement of L-glutamine.

The amino acid L-glutamine has been shown to be important to numerous cells in the body. However, the routine measurement of glutamine in biological solutions is complicated by its relative instability, particularly at extremes of pH. We report a simple bacterial bioassay method for the estimation of glutamine, carried out at neutral pH, using an Escherichia coli that is specifically dependent on the presence of glutamine for replication. The assay is simple to perform and we have shown it to be highly reproducible. Furthermore, we observed significant correlation between the estimations of glutamine by the bioassay system and current methodologies. The levels of glutamine recorded were higher than by other methods. We also found that deproteinization and neutralization of samples allowed them to be stored at -70 degrees C for up to 24 weeks without deterioration.

Biological Assay↗
PubMed1998

The influence of exercise-induced plasma volume changes on the interpretation of biochemical parameters used for monitoring exercise, training and sport.

A number of studies have demonstrated considerable plasma volume changes during and after exposure to different environmental and physiological conditions. These changes are thought to result from transient fluid shifts into (haemodilution) and out of (haemoconcentration) the intravascular space. If the levels of plasma constituents are to be routinely measured for research purposes or used as indicators of training adaptation or the health of an athlete, then it is important to consider the dynamic nature of plasma volume. Controversy still exists over the relevance of plasma volume interactions with plasma constituent levels, and while some investigators have taken plasma volume shifts into account, others have chosen to ignore these changes. Bouts of acute exercise have been shown to produce a transient haemoconcentration immediately after long distance running, bicycle ergometry and both maximal and submaximal swimming exercise. While these changes are transient, lasting only a few hours, other studies have reported a longer term haemodilution following acute exercise. In addition, endurance training has been shown to cause long term expansion of the plasma volume. It would, therefore, seem important to consider the influence of plasma volume changes on plasma solutes routinely measured for research, and as markers of training adaptation, prior to arriving at conclusions and recommendations based purely on their measured plasma level. To further confound this issue, plasma volume changes are known to be associated with heat acclimatisation, hydration state, physical training and postural changes, all of which may differ from one experiment or exercise bout to the next, and should thus be taken into account.

Blood Chemical Analysis↗
PubMed1997

Acute intensive interval training and in vitro t-lymphocyte function.

Five male endurance-trained runners completed an interval running session of 15 x 1-min intervals at 95% VO2 max. Venous blood samples were collected pre-exercise and then immediately, 30- and 60-minutes post-exercise. The response of cultures of total lymphocytes to mitogen (phytohaemagglutinin) were significantly reduced immediately after exercise, but returned to resting levels by 30-min of recovery. Conversely, the mitogen response of cultures of pure T-lymphocytes (CD4+ and CD8+ cells), separated using a magnetic separation technique, showed no significant change during the exercise and recovery periods. These data showed directly that there was no apparent change in the functional capability of T-lymphocytes following an intensive interval training session. Furthermore, there were significant changes in the composition of the total lymphocyte cultures immediately post-exercise; increased numbers of natural killer (NK) cells (CD56+) and T-suppressor cells (CD8+) and decreased numbers of T-helper cells (CD4+). There were also significant correlations between total mitogen response and the composition of the cultured lymphocytes. These data indicated that the large increases in NK cells, relative to T-cells, following intensive exercise, were the most likely cause of the reduced mitogen response of total lymphocyte cultures.

Adult↗
PubMed1997

The influence of blood volume changes on leucocyte and lymphocyte subpopulations in elite swimmers following interval training of varying intensities.

The effect that exercise induced blood volume (BV) changes may have on the concentrations of leucocyte and lymphocyte subpopulations following exercise is controversial. Eight nationally ranked swimmers undertook 15 x 100 m swimming intervals (ITS) at 70% and 95% of maximal exercise intensity separated by 2 min recovery periods. Venous blood samples were collected prior to exercise (PRE), immediately post exercise (POST) and at 30, 60, 120 and 150-min post exercise. Control samples were taken on a rest day (R). Only the 95% ITS induced a significant (p < 0.01) reduction in PV (-7.3 +/- 1.1%) and BV (-4.0 +/- 0.6%) POST as calculated according to changes in haemoglobin and haematocrit. Total leucocyte and subset numbers (neutrophils, lymphocytes, monocytes), with the exception of eosinophils, increased significantly (p < 0.01) POST following the 95% ITS, and total leucocyte and neutrophils remained elevated (30% and 114% respectively) (p < 0.01) while lymphocytes progressively decreased by 36% (p < 0.01) at 150-min after exercise. The 70% ITS elicited a decrease (30%) (p < 0.01) only in lymphocyte cell numbers at 60 and 120-min post exercise. The 95% ITS induced significant increases (p < 0.01) in most lymphocyte cell subsets [CD19+ (27%); CD16+ (525%); CD16+ CD25+ (58%); CD4+ (48%); CD8+ (65%)] POST, with a significant reduction (32%) (p < 0.01) in the CD4+:CD8+ lymphocyte ratio. Numbers of CD19+; CD16+; CD5+; CD4+ and CD8+ lymphocytes, while not significantly changed POST following the 70% ITS, were significantly depressed (p < 0.01) during the recovery period. No significant changes were seen in leucocyte or lymphocyte subset numbers during R. All measured leucocyte and lymphocyte subset cell numbers at each ITS were corrected for changes in BV, and there were no significant differences between measured or BV corrected values for any of the cell populations at either of the ITS. Results suggest that while high intensity swimming exercise stress caused significant changes in the numbers and proportions of leucocytes, lymphocytes and their sub-classes, BV changes did not contribute significantly to the changes which occurred. The cell changes therefore, were truly representative of cell movements into and out of the peripheral blood circulation.

Adolescent↗
PubMed1997

Training adaptation and biological changes among well-trained male triathletes.

The distinction between training and overtraining responses is an important prerequisite for any potential marker for monitoring overtraining in athletes. In this study, eight well-trained male triathletes undertook physical performance assessments, at 6 weekly intervals, throughout a 9-month intensive training season. At each assessment, a resting blood sample was obtained for determination of a number of biological parameters previously associated with overtraining. All athletes produced significant (P < 0.05) improvements in running speed at anaerobic threshold (ATRS) from 15.6 +/- 0.2 k.h-1 at the start of the season to 16.6 +/- 0.6 k.h-1 at the time of major competitions. This improvement in performance was taken as evidence of well balanced training programs. Significant changes (P < 0.05) in plasma glutamine and plasma uric acid concentrations were observed during the training season, and both correlated moderately with ATRS (r = 0.365 and r = -0.328, respectively). None of the other parameters measured showed any significant changes during the training season. The elevations in plasma glutamine concentration observed in response to long-term balanced training may be distinguishable from previous reports of decreased glutamine concentrations in overtrained athletes, making it a potentially valuable tool in the monitoring of overtraining in athletes.

Adult↗
PubMed1997

Influence of exercise-induced plasma volume changes on the interpretation of biochemical data following high-intensity exercise.

OBJECTIVE: To assess the effects that exercise-induced plasma volume changes (PVCs) have on the interpretation of biochemical and hormonal parameters in the blood of athletes after high-intensity exercise. It was hypothesized that two unrelated high-intensity exercise protocols, performed by two separate subject groups each using different exercise modes, would result in similar percentage changes in plasma volume (% delta PV). It was further hypothesized that the % delta PV, measured in both protocols, would comparably influence the interpretation of biochemical variables measured following exercise. DESIGN: An experimental before-after trial on volunteers was performed. Two different exercise modes employing two different high-intensity acute exercise protocols were investigated. Eight male swimmers performed an interval training session (ITS) consisting of 15 x 100-m freestyle efforts at 95% of their maximal exercise intensity, and eight male runners performed a multistage discontinuous treadmill test (MSD) to volitional exhaustion. SETTING: The Human Performance Laboratory at the Department of Human Movement at the University of Western Australia. MAIN OUTCOME MEASURES: Blood samples obtained before, immediately after, and 30, 60, and 120 min during recovery were analyzed for plasma volume changes, urea, uric acid, creatinine, albumin, calcium, iron, transferrin, testosterone, cortisol, and sex hormone-binding globulin (SHBG). MAIN RESULTS: The ITS and MSD protocols produced similar and significant alterations (p < 0.01) in plasma volume. Both protocols also elicited significant fluctuations (p < 0.01) in the concentration of most of the parameters measured (excluding iron). When albumin, transferrin, testosterone, and SHBG values were adjusted for the significant % delta PV, their concentrations did not change over the experimental period, suggesting that the changes in measured concentration of these parameters may be, in part, due to changes in plasma volume. However, urea, uric acid, creatinine, calcium, and cortisol, when corrected for % delta PVC, still demonstrated significant changes (p < 0.01). CONCLUSIONS: It is recommended, when sampling biochemical and hormonal parameters in blood following an acute bout of exercise, that corrections for PVCs should be conducted. Apparent changes in blood solutes may reflect PVCs. PVCs should be taken into consideration when interpreting results regardless of exercise protocol and exercise mode performed.

Blood Chemical Analysis↗
PubMed1996

The emerging role of glutamine as an indicator of exercise stress and overtraining.

Glutamine is an amino acid essential for many important homeostatic functions and for the optimal functioning of a number of tissues in the body, particularly the immune system and the gut. However, during various catabolic states, such as infection, surgery, trauma and acidosis, glutamine homeostasis is placed under stress, and glutamine reserves, particularly in the skeletal muscle, are depleted. With regard to glutamine metabolism, exercise stress may be viewed in a similar light to other catabolic stresses. Plasma glutamine responses to both prolonged and high intensity exercise are characterised by increased levels during exercise followed by significant decreases during the post-exercise recovery period, with several hours of recovery required for restoration of pre-exercise levels, depending on the intensity and duration of exercise. If recovery between exercise bouts is inadequate, the acute effects of exercise on plasma glutamine level may be cumulative, since overload training has been shown to result in low plasma glutamine levels requiring prolonged recovery. Athletes suffering from the overtraining syndrome (OTS) appear to maintain low plasma glutamine levels for months or years. All these observations have important implications for organ functions in these athletes, particularly with regard to the gut and the cells of the immune system, which may be adversely affected. In conclusion, if methodological issues are carefully considered, plasma glutamine level may be useful as an indicator of an overtrained state.

Animals↗
PubMed1996

Inter-relationships between glutamine and other biochemical and immunological changes after major vascular surgery.

It has been suggested that increased susceptibility to infection sometimes seen following surgery might be related to levels of circulating glutamine. However, previous studies have not investigated the degree of immune cell activation in relation to availability of glutamine after surgery. In seven patients plasma glutamine concentration decreased by about 50% immediately after major vascular surgery, and took 5 days to recover to normal levels. Although plasma glutamate concentration was inversely related to glutamine, glutamate levels were some three times lower. The circulating numbers of platelets, neutrophils, monocytes and lymphocytes (specifically CD4+ cells) were significantly related to both the concentration of glutamine and glutamate irrespective of time. However, there was no evidence of cell activation as indicated by expression of activation markers (CD69, CD25, CD71 or HLA-DR) on lymphocytes. Creatine kinase activity significantly increased after operation, indicating the presence of substantial post-operative trauma. Transferrin, iron and magnesium were the other biochemical parameters which significantly decreased after surgery, while albumin levels suggested that blood transfusions may have contributed to the changes seen.

Aged↗
PubMed1995

Depression of plasma glutamine concentration after exercise stress and its possible influence on the immune system.

OBJECTIVE: To determine whether plasma glutamine levels can be used as an indicator of exercise-induced stress, and to consider the possible effects of low plasma glutamine concentrations on the immune system. METHODS: We used two exercise regimens: in Trial 1 seven male subjects were randomly stressed on a treadmill at 0, 30%, 60%, 90% and 120% of their maximal oxygen uptake (VO2max); in Trial 2 five highly trained male subjects underwent intensive interval training sessions twice daily for ten days, followed by a six-day recovery period. RESULTS: Plasma glutamine concentrations decreased significantly from an average of 1244 +/- 121 mumol/L to 702 +/- 101 mumol/L after acute exercise at 90% VO2max (P < 0.05) and to 560 +/- 79 mumol/L at 120% VO2max (P < 0.001). Four of the five subjects showed reduced plasma glutamine concentrations by Day 6 of the overload training trial, with all subjects displaying significantly lower glutamine levels by Day 11. However, glutamine levels showed a variable rate of recovery over the six-day recovery period, with two subjects' levels remaining low by Day 16. CONCLUSIONS: Reduced plasma glutamine concentrations may provide a good indication of severe exercise stress.

Exercise↗
PubMed1995

The haematological, biochemical and immunological profile of athletes suffering from the overtraining syndrome.

To help clarify the overtraining syndrome (OTS), a combination of parameters were measured in ten athletes who were suffering from OTS. Blood samples were obtained at rest and a range of haematological, biochemical and immunological tests were carried out on the samples. For each parameter, the mean value for the group was compared to an established normal range amongst age-matched controls. The subjects were also asked to complete a questionnaire to establish the severity of their condition. The data indicated that the debilitating fatigue experienced by the OTS sufferers was not related to any of the blood parameters traditionally associated with chronic exercise stress, since levels were normal in OTS. The only parameter measured which deviated significantly from the normal range for both the sedentary controls and the athletes was the plasma concentration of glutamine. Although the data in this study would suggest that plasma glutamine concentrations represented an objective, measurable difference between OTS subjects and normal controls, it remains to be shown that there is any correlation between glutamine concentrations and other clinical symptoms of OTS such as physical capability.

Adult↗
PubMed1995

Serum free cortisol responses to a standard exercise test among elite triathletes.

Eighteen elite male triathletes completed an incremental treadmill run to volitional exhaustion, followed by two maximal cycle ergometer sprints. Venous blood samples were obtained at rest (R), immediately post- (P) and one hour postexercise (H). Serum was analysed for total cortisol (TC) by a radioimmunoassay, and free cortisol (FC) by a temperature and time dependent ultrafiltration/dialysis method. Mean (+SE) resting cortisol levels were 627 + or - 23 (TC) and 12.5 + or - 2.5 nmol 1(-1)(FC). The mean percentage increase in TC (P vs. R) was 49.0 + 73%, accompanied by a 344 + or - 47% increase in FC. Significantly divergent (p<0.001) total cortisol responses (H vs. P) were observed within the group, and the athletes were divided into two subgroups (A and B) on this basis. In group A, both TC and FC returned to resting levels. In group B, there was a further slight increase in TC, accompanied by a significant (p<0.01) increase in FC reaching 851 + or - 268% of resting levels. These data suggest that exercise-induced increases in free cortisol, and hence its catabolic effect, are of much greater relative magnitude than TC changes. The relationship between TC and FC was best fitted to an exponential regression, with a clearcut change in slope at 700 nmol 1(-1)(TC) suggesting saturation of the binding protein. We suggest that the measurement of cortisol in athletes be reassessed, favouring determination of FC in the future.

Adult↗