Hypercalcaemia in patients receiving dialysis.
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Humans↗
Biomedical subjects
A R Morton
Publications and source records attributed to A R Morton.
Cell numbers and in vitro responses of leucocytes and lymphocyte subpopulations following maximal exercise and interval training sessions of different intensities.
In vitro lymphocyte function and the mobilisation of peripheral blood leucocytes was examined in eight trained subjects who undertook an incremental exercise test to exhaustion and a series of interval training sessions. Venous blood samples were obtained before the incremental test, immediately after, and 30, 60, and 120 min after the test. Interval training sessions were undertaken on separate days and the exercise intensities for each of the different sessions were 30%, 60%, 90% and 120% of their maximal work capacity respectively, as determined from the incremental exercise test. There were 15 exercise periods of 1-min duration separated by recovery intervals of 2 min in each session. Venous blood samples were obtained immediately after each training session. Significant increases in lymphocyte subpopulations (CD3+, CD4+, CD8+, CD20+, and CD56+) occurred following both maximal and supramaximal exercise. This was accompanied by a significant decrease in the response of cultures of peripheral blood lymphocytes to Concanavalin A (ConA), a T-cell mitogen. The state of lymphocyte activation in vivo as measured by CD25+ surface antigen was not, however, affected by acute exercise. The total number of lymphocytes, distribution of lymphocyte subpopulations and in vitro lymphocyte response to ConA had returned to pre-exercise levels within half an hour of termination of exercise but serum cortisol concentrations had not begun to fall at this time. There was a significant decrease in the CD4+:CD8+ cell ratio following exercise; this was more the result of increases in CD3-CD8+ cells (CD8+ natural killer cells) than to CD3+CD8+ cells (CD8+ T-lymphocytes). Decreased responsiveness of T-cells to T-cell mitogens, postexercise, may have been the result of decreases in the percentage of T-cells in postexercise mixed lymphocyte cultures rather than depressed cell function. The cause of this was an increase in the percentage of natural killer cells which did not respond to the T-cell mitogen. The results indicated that while a substantial immediate in vitro "immunomodulation" occurred with acute exercise, this did not reflect an immunosuppression but was rather the result of changes in the proportions of reactive cells in mononuclear cell cultures. We have also demonstrated that the degree of the change in distribution of lymphocyte subpopulation numbers and responsiveness of peripheral blood mononuclear cells in in vitro mitogen reactions increased with increasing exercise intensity. Plasma volume changes may have contributed to some of the changes seen in leucocyte population and subpopulation numbers during and following exercise.
CD4-CD8 Ratio↗
Biological responses to overload training in endurance sports.
Five subjects undertook 10 days of twice daily interval training sessions on a treadmill followed by 5 days of active recovery. On days 1, 6, 11, and 16 the subjects were required to undertake a test of submaximal and maximal work capacity on a treadmill combined with a performance test consisting of a run to exhaustion with the treadmill set at 18 km.h-1 and 1% gradient. Also on these days a pre-exercise blood sample was collected and analysed for a range of haematological, biochemical and immunological parameters. The subjects experienced a significant fall in performance on day 11 which had returned to pretraining levels on day 16. Serum ferritin concentrations were depressed significantly from pretraining concentrations at the conclusion of the recovery period while the expression of lymphocyte activation antigens (CD25+ and HLA-DR+) was increased both after the training phase and the recovery phase. The number of CD56+ cells in the peripheral circulation was depressed at the conclusion of the recovery period. Several parameters previously reported to change in association with overload training failing to reflect the decrease in performance experienced by subjects in this study, suggesting that overtraining may best be diagnosed through a multifactorial approach to the recognition of symptoms. The most important factor to consider may be a decrease in the level of performance following a regeneration period. The magnitude of this decreased performance necessary for the diagnosis of overtraining and the nature of an "appropriate" regeneration period are, however, difficult to define and may vary depending upon the training background of the subjects and the nature of the preceding training. It may or may not be associated with biochemical, haematological, physiological and immunological indicators. Individual cases may present a different range of symptoms and diagnosis of overtraining should not be excluded based on the failure of blood parameters to demonstrate variation. However, blood parameters may be useful to identify possible aetiology in each separate case report of over-training. An outstanding factor to emerge from this study was the difficulty associated with an objective diagnosis of overtraining and this is a possible reason why there have been new accounts of overtraining research in the literature.
Adult↗
Infusion rate and pharmacokinetics of intravenous pamidronate in the treatment of tumour-induced hypercalcaemia.
We report the results of two consecutive randomized studies in the treatment of malignant hypercalcaemia with intravenous pamidronate. Overall normocalcaemia was achieved in greater than 90% of patients and a single infusion of 60 mg pamidronate given over 2 hours was as effective in restoring normocalcaemia as infusions given over 4, 8 or 24 hours. Similarly duration of normocalcemia after treatment with pamidronate and the control of the symptoms of hypercalcaemia were independent of infusion rate. Study of the pharmacokinetics of pamidronate in the treatment of hypercalcaemia show this drug to have a very high clearance due to calcified tissue retention and renal excretion. The initial half life of the drug in plasma is very short and most of the drug is cleared before distribution equilibrium is achieved. Short infusions of pamidronate are as safe and effective as infusions given over a longer time and are therefore to be preferred because of their greater convenience.
Adult↗
Asthmatic drugs and competitive sport. An update.
Almost all asthmatics are prone to asthma triggered by moderate to severe exercise. Fortunately there are a number of pharmaceutical agents now available which can prevent and/or reverse exercise-induced asthma (EIA) and allow many asthmatics to participate in vigorous physical activities with minimum respiratory disadvantage. Regular exercise is an accepted part of the management of asthma and EIA can now be controlled so successfully that a number of elite sportspersons, in almost all types of sporting events, are asthmatic. This control of EIA, which is essential if asthmatics are to participate safely, requires that the patient and his/her doctor initiate a strategy to manage the disease during sport and other physical activities. In recent years the mortality and morbidity from asthma have been increasing and this has indicated the need to improve patient care. One of the most important innovations aiming to improve the control and treatment of asthma has been the recent development of the 6 point asthma management plan which is a strategy to simplify and optimise the long term management of asthma. It aims to improve the quality of life of most asthmatics and more importantly, prevent deaths due to asthma. Because antidoping controls operate in many high performance sports it is essential that the EIA management plan rely on those medications which are permitted. The list of allowable drugs is in continual flux as new ones are added and others are challenged on the grounds of possible ergogenicity. All aerosol beta 2-agonists except fenoterol, the khellin derivatives, theophylline, ipratropium bromide and the aerosol corticosteroids are currently permitted. Some nonasthmatic athletes who are aware of the improved performance of asthmatic athletes when using pre-exercise medication have been known to take antiasthma medication in the hope that it might improve their performance. Current evidence indicates, however, that the permitted medications are not ergogenic and do not give the asthmatic any advantage over the nonasthmatic athlete but merely removes the respiratory disadvantage under which he/she competes.
Administration, Inhalation↗
Effects of nedocromil sodium, cromolyn sodium, and a placebo in exercise-induced asthma.
The incidence and severity of exercise-induced asthma were determined in nineteen asthmatic patients who performed eight minutes of exercise following four treatments administered in a random order. The treatments were nedocromil sodium, cromolyn sodium, placebo, and no treatment. It was concluded that nedocromil sodium (8 mg) and cromolyn sodium (4 mg) provide equal protection against exercise-induced asthma.
Adolescent↗
Periodisation of training stress--a review.
Athletic performance improves as the athlete adapts to progressively increasing training loads. Empirical observations and studies investigating fluctuations in performance indicate that this adaptation occurs during periods of reduced training, termed regeneration periods. Thus it is essential that adequate regeneration time be included in training programmes so that adaptation can be achieved. In order to induce adaptation, heavy periods of training are used to provide a stimulus for adaptive processes to become functional. The literature and anecdotal accounts suggest that the cycling of light, medium, and heavy periods of training is an optimal method for combining the heavy periods of training with the periods of light training needed to allow adaptation and supercompensation.
Adaptation, Physiological↗
Periodisation and the prevention of overtraining.
It may be essential for the athlete to train in cycles in order to induce optimal improvements and prevent overtraining. Without sufficient recovery time, adaptation may not occur and the athlete may develop the symptoms of overtraining due to continuous and/or excessive exposure to training stress. Training in cycles provides guidelines for the times in the training programme when regeneration should be complete, and therefore the times when the athlete can be screened for overtraining without confusing the fatigue of overload training with that of overtraining. A periodised training structure provides guidelines for conducting research into the mechanisms of training adaptation and overtraining.
Adaptation, Physiological↗
Acute intensive interval training and T-lymphocyte function.
Immune suppression has been suggested to occur as a result of acute exercise although results of previous studies are variable, possibly due to the failure of some researchers to control exercise intensity and duration. Most of the studies so far have investigated immediate effects after bouts of exercise mainly in subjects undertaking lower body exercise (running or cycling), and the time course of recovery has rarely been determined. We chose two groups of athletes for our studies. One group represented subjects of a range of fitness levels from recreational runners to high-performance runners. The second group represented kayakists with a similar range of fitness levels. Following interval training designed to stress either the lower or upper body anaerobically, we have now shown that upper body exercise (kayaking) induces similar in vitro responses to those described for lower body exercise. There were no differences between the responses of low-fitness versus high-fitness subjects. In addition we have studied the in vitro responses of leukocytes following acute anaerobic exercise over a 24-h recovery period. The results showed that the reduced lymphocyte proliferative response, in vitro, to the T-cell mitogen CONA experienced immediately after exercise returned to normal levels within 2 h of recovery time. This suggests that the reduction in lymphocyte proliferative response is a short transient one.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Monitoring exercise stress by changes in metabolic and hormonal responses over a 24-h period.
Metabolic and endocrine responses of 14 subjects of varying levels of fitness to an intensive anaerobic interval training session were assessed before exercise and at 2 h, 4 h, 8 h and 24 h postexercise. The endocrine response of the same subjects to a control day, where they were required not to exercise, was also assessed and compared with the values obtained on the interval training day. Uric acid, urea, and creatine phosphokinase concentrations still remained elevated above pre-exercise values 24 h postexercise. Lactate, creatinine, testosterone and cortisol concentrations were significantly elevated above pre-exercise values immediately postexercise but these had reversed by 2 h postexercise. Over the remainder of the recovery period testosterone concentrations remained significantly lower than values measured at similar times on the control day. This was shown to be due directly to a change in testosterone as sex hormone binding globulin concentration remained constant throughout the recovery period. The data indicate that when comparisons of data were made to control (rest) days, imbalances in homeostasis, due to intensive training, are not totally reversed within the next 24-h. The data also demonstrate that the parameters measured undergo the same variations in subjects with a wide range of physical fitness, indicating that these parameters could be used to monitor exercise stress and recovery in athletes of a wide range of abilities.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Parathyroid hormone-related protein(50-69) and response to pamidronate therapy for tumour-induced hypercalcaemia.
A region-specific radioimmunoassay has been employed to measure levels of immunoreactive parathyroid hormone-related protein(50-69) (iPTHrP(50-69)) in patients with tumour-induced hypercalcaemia (TIH). This assay is based on an antiserum raised against synthetic human PTHrP(50-69). The assay showed no cross-reactivity with human or bovine parathyroid hormone(1-84). The effect of a single dose (60 mg) of pamidronate was studied in 25 consecutive patients with TIH. All were rehydrated prior to treatment. All but 2 patients (8%) became normocalcaemic after treatment; both of these had very high levels of iPTHrP(50-69). Time to achieve normocalcaemia, as an index of relative resistance to pamidronate, correlated positively with pretreatment level of iPTHrP(50-69). Absence of radiological evidence of bone metastases also predicted relative resistance to pamidronate. In this study, iPTHrP(50-69)-induced osteoclastic bone resorption was a more important mechanism in the causation of TIH than PTHrP-induced renal reabsorption of calcium as assessed by the renal thresholds for calcium and phosphate.
Adult↗
Medical and social outcome in adolescents with end-stage renal failure.
Clinical information was collected on 118 adolescents who developed ESRF at age 143 months or older and were treated between 1966 and 1986 at the Toronto Hospital for Sick Children. The cumulative survival rate in transplanted patients (N = 109) was 80.1% after 15 years. Survival rates after four years were 93.9% in transplanted and 46.9% in nontransplanted patients (P less than 0.001). No patient receiving dialysis alone (N = 9) was followed longer than four years. Nine patients received three transplants and had an 89% survival rate. Six of these had a functioning graft at end of the follow-up. The cumulative survival of the entire group was 76.4% at eighteen years. Forty-two (35.6%) patients had a height below the third percentile. Functional status obtained by a structure telephone interview with a member of the present treating nephrology service was good (G) or excellent (E) for 66.7% of all patients (73.5% of transplant patients (N = 68) and 45% of dialysis patients (N = 20). Hemodialysis patients functioned less well [25% G/E (N = 12)] than peritoneal dialysis patients [75% G/E (N = 8)]. Most patients achieved an appropriate level of formal education although more slowly than normal adolescents. Only 11 patients were neither enrolled in an educational institution nor employed. We conclude that aggressive treatment for adolescents with ESRF is an appropriate application of health care resources.
Adolescent↗
A controlled study of the effects of aerobic exercise on antihypertensive drug requirements of essential hypertensive patients in the general practice setting.
1. To investigate the effect of an exercise training programme on antihypertensive drug requirements, 19 sedentary subjects (14 men and five women) with mild essential hypertension (systolic blood pressure greater than 140 mmHg but less than 180 mmHg), aged 29-55 years, were randomly assigned to 16 weeks of moderate intensity exercise or light intensity exercise (control), and titrated on antihypertensive drug therapy (captopril and hydrochlorothiazide) until resting systolic blood pressure (sitting) of less than 140 mmHg was achieved. 2. The moderate exercise group (n = 11) followed a graded walk-jog programme to greater than 60% age-predicted maximum heart rate (HRmax), attending 45 min sessions, three times each week. The light exercise group (n = 8) followed a programme of flexibility (stretching exercises) and walking to less than 60% age-predicted HRmax, attending 45 min sessions, three times each week. 3. There was no difference between treatment groups for the level of reduction in both resting systolic and diastolic blood pressure over the 16 weeks (15.64 +/- 10.6/12.81 +/- 9.97 mmHg in the moderate intensity group and 15.31 +/- 10.9/7.7 +/- 7.1 mmHg in the light intensity group). The change in 24 h ambulatory blood pressure profile was also similar in both treatment groups. The final antihypertensive drug requirements to achieve these changes in blood pressure was not significantly different between the two treatment groups. This was despite a significant improvement in submaximal exercise performance in the moderate intensity exercise group (P less than 0.001). 4.(ABSTRACT TRUNCATED AT 250 WORDS)
Adolescent↗
Overtraining in athletes. An update.
Overtraining appears to be caused by too much high intensity training and/or too little regeneration (recovery) time often combined with other training and nontraining stressors. There are a multitude of symptoms of overtraining, the expression of which vary depending upon the athlete's physical and physiological makeup, type of exercise undertaken and other factors. The aetiology of overtraining may therefore be different in different people suggesting the need to be aware of a wide variety of parameters as markers of overtraining. At present there is no one single diagnostic test that can define overtraining. The recognition of overtraining requires the identification of stress indicators which do not return to baseline following a period of regeneration. Possible indicators include an imbalance of the neuroendocrine system, suppression of the immune system, indicators of muscle damage, depressed muscle glycogen reserves, deteriorating aerobic, ventilatory and cardiac efficiency, a depressed psychological profile, and poor performance in sport specific tests, e.g. time trials. Screening for changes in parameters indicative of overtraining needs to be a routine component of the training programme and must be incorporated into the programme in such a way that the short term fatigue associated with overload training is not confused with the chronic fatigue characteristic of overtraining. An in-depth knowledge of periodisation of training theory may be necessary to promote optimal performance improvements, prevent overtraining, and develop a system for incorporating a screening system into the training programme. Screening for overtraining and performance improvements must occur at the culmination of regeneration periods.
Adaptation, Physiological↗
Physiological and kinanthropometric attributes of elite flatwater kayakists.
Physical and physiological factors accounting for the variability of performance in 500, 1000, 10,000, and 42,000 m flatwater kayaking were investigated using linear regression. Times achieved for each distance were used as the dependent variable for analysis while the independent variables were the parameters derived from the test battery. The 38 kayakists who participated were categorized as either state team members or nonselected paddlers, based on an objective selection policy. Several of the participant subjects were Australian international representatives. All selected paddlers were grouped together and Student's t-tests performed to determine which variables could distinguish between selected and nonselected paddlers. Simple regression was used to determine the strength of association of each parameter with performance time over each race distance, and multiple regression was used to generate equations for the prediction of performance times. Aerobic power and variables related to the aerobic-anaerobic transition were examined using gas analysis during an incremental workload test on a kayak ergometer. A 1-min all-out test also on a kayak ergometer was used to obtain an indication of anaerobic capacity and power. Muscular strength and fatigue were assessed using a simulated kayak stroke on a Cybex isokinetic dynamometer. Physical characteristics were determined using kinanthropometric tests. Aerobic power, anaerobic power and capacity, muscular strength, resistance to muscular fatigue, and measures of body size were significantly greater in more successful kayakists. All of the parameters measured correlated significantly with performance time over at least one of the four race distances.(ABSTRACT TRUNCATED AT 250 WORDS)
Adaptation, Physiological↗
Dose of bisphosphonate for hypercalcaemia of malignancy.
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Aged↗
Controlled comparison of effects of exercise and alcohol on blood pressure and serum high density lipoprotein cholesterol in sedentary males.
1. Seventy-two sedentary male drinkers, aged 20-45 years, and with mean blood pressure (BP) at entry of 132 +/- 1.2/73 +/- 0.9 mmHg, completed a 4 week study during which they were assigned randomly to either drink a low alcohol beer (effectively reducing their weekly alcohol intake from 481 +/- 47 mL to 52 +/- 5 mL) or to continue their normal drinking habits. 2. Within these two groups subjects were further assigned to either a moderate exercise programme of three 30 min sessions per week of stationary cycling at 60-70% maximum workload or to a control light exercise programme where they pedalled against zero or minimal resistance. 3. Both alcohol restriction and moderate exercise were associated with mean falls in bodyweight of 0.5 kg. After adjustment for bodyweight a significant main effect of alcohol restriction on systolic BP (-4.1 +/- 1.7 mmHg, P less than 0.05) and diastolic BP (-1.6 +/- 0.8 mmHg, P = 0.05) was demonstrated. There was no significant main effect of moderate exercise on systolic or diastolic blood pressure despite a significant improvement in physical fitness (maximal oxygen uptake increasing from 33.2 +/- 0.8 mL/kg per min to 35.5 +/- 0.1 mL/kg per min). 4. Significant falls in high density lipoprotein cholesterol (HDLC) and triglyceride levels seen with alcohol restriction were unaffected by the increase in fitness, the magnitude of the fall being similar in both the moderate and light exercise groups.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
CO2 sensitivity changes during the menstrual cycle.
A study of the changes in CO2 sensitivity at rest was undertaken in 20 regularly menstruating females in an attempt to determine the influence of the menstrual cycle on this variable. A biphasic oral temperature graph was used to signify fertility and demarcate three phases of the cycle. A CO2-rebreathing test was conducted 3 times/wk for 6 wk to obtain CO2 sensitivity and CO2 threshold measures. An analysis of variance was used to compare the results collected in each phase of the cycle for each of the variables. A significant increase was found in the sensitivity to CO2 between the follicular and luteal phases, a significant decrease between the luteal and menstrual phases, and no significant difference between the follicular and menstrual phases. The change between follicular and luteal phases was attributed to the effect of progesterone, which is elevated during the luteal phase. No significant change was found in the CO2 threshold level.
Adolescent↗