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Biomedical subjects

P J Robson

Publications and source records attributed to P J Robson.

At least 55 records · Page 3Linked to original sources
PubMed2000

Bioavailability of n-3 polyunsaturated fatty acids (PUFA) in foods enriched with microencapsulated fish oil.

OBJECTIVE: Incorporation of fish oil into food products provides a means of increasing n-3 fatty acid intake, particularly in populations where fish consumption remains low. The aim of the present study was to evaluate the bioavailability of n-3 PUFA in microencapsulated fish-oil-enriched foods compared with an equal amount of n-3 PUFAs contained in fish oil capsules. METHODS: Twenty-five healthy female volunteers were randomly assigned to one of two groups for the 4-week intervention: one group received 0.9 g of n-3 PUFA/day as fish oil capsule (capsule group), while the second group (food group) received an equal amount of n-3 PUFA/day from enriched foods. Baseline and post-intervention samples were analysed for platelet fatty acid composition. RESULTS: There was no significant difference in the change in platelet arachidonic acid (AA), eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA) between the two groups following the intervention. CONCLUSIONS: The results indicate that n-3 PUFA from microencapsulated fish-oil-enriched foods are as bioavailable as n-3 PUFA in a capsule. Fortification of foods with microencapsulated fish oil, therefore, offers an effective way of increasing n-3 PUFA intakes and status in line with current dietary recommendations.

Adult↗
PubMed2000

Tracking of nutrient intakes in adolescence: the experiences of the Young Hearts Project, Northern Ireland.

This study evaluated the tracking of energy and nutrient intakes, assessed by diet history, in a random sample of adolescents (boys n 225, girls n 230) at baseline (age 12 years), and subsequently at age 15 years. Median energy (MJ/d) and macronutrient (g/d) intakes increased significantly (all P < 0.001) with increasing age in the boys. The girls' reported energy intake (MJ/d) remained stable over time, despite significant increases in BMI, weight and % body fat. Age-related changes in the girls' macronutrient intakes were inconsistent. When expressed in terms of nutrient density, the diets of both sexes became significantly richer, over time, in total folate (both sexes, P < 0.01), but poorer in Ca (boys P < 0.01, girls P < 0.001) and riboflavin (both sexes P < 0.001). Vitamin B6 (P < 0.001) and Fe (P < 0.05) densities increased in the boys, while the thiamin density of the girls' diets decreased (P < 0.001). Tracking, defined as maintenance of rank over time, was summarised using weighted kappa statistics (kappa). There were some significant changes in intakes at the group level; however, tracking of energy and nutrients in both sexes was only poor to fair (kappa < 0.40), indicating substantial drift of individuals between classes of intake over time. Particularly poor tracking was evident for % energy from sugars (kappa 0.09) and total fat (kappa 0.09) in the girls' diets. In conclusion, the poor to fair tracking observed in this cohort suggests that individual dietary patterns exhibited at 12 years of age are unlikely to be predictive of energy and nutrient intake at age 15 years.

Adolescent↗
PubMed1999

Effects of exercise intensity, duration and recovery on in vitro neutrophil function in male athletes.

The aim of the present study was to compare the effects of exercise at 80% VO2max (resulting in fatigue within 1 h) with more prolonged exercise at a lower work rate (55% VO2max for up to 3 h) on blood neutrophil function and plasma concentrations of cortisol, glutamine and glucose. Eighteen healthy male subjects (mean+/-SD age 22.5+/-3.7 yrs, VO2max 60.1+/-6.6 ml x kg(-1) x min(-1)) cycled on an electrically braked ergometer at 80% VO2max to fatigue (37+/-19 min). On another occasion, separated by at least one week, subjects performed exercise on the same ergometer at 55% VO2max for 3 h or to fatigue, whichever was the sooner. Mean exercise time was 164+/-23 min. The order of the trials was randomised. Both exercise bouts caused significant (p<0.05) elevations of the blood leucocyte count and plasma cortisol concentration and reductions in the in vitro neutrophil degranulation response to bacterial lipopolysaccharide and oxidative burst activity. After exercise at the lower work rate for a longer duration, plasma cortisol concentration was higher, blood leucocyte and neutrophil counts were higher, blood lymphocytes, plasma glucose and indices of neutrophil function were lower than those observed at 80% VO2max. Plasma glutamine only fell significantly during recovery after the more prolonged exercise. We conclude that when exercise is very prolonged, the diminution of innate immune function is greater, or at least as great as that observed after fatiguing exercise at higher work rates. Furthermore, reductions in neutrophil function after exercise at 80% VO2max were not related to changes in the plasma glutamine concentration, although both plasma glutamine and neutrophil function were decreased at 1 and 2.5 h post-exercise in the long duration exercise trial.

Adult↗
PubMed1999

The effects of carbohydrate supplementation on immune responses to a soccer-specific exercise protocol.

The aim of this study was to determine the effect of carbohydrate (CHO) versus placebo (PLA) beverage consumption on the immune and plasma cortisol responses to a soccer-specific exercise protocol in 8 university team soccer players. In a randomized, counterbalanced design, the players received carbohydrate or placebo beverages before, during and after two 90 min soccer-specific exercise bouts (3 days apart) designed to mimic the activities performed and the distance covered in a typical soccer match. Blood and saliva samples were collected before, during and after the exercise protocol. Plasma lactate concentration increased to approximately 4 mmol x l(-1) at 45 and 90 min of exercise in both treatments (P<0.01). Plasma glucose concentration was significantly lower after 90 min of exercise with ingestion of the placebo than the carbohydrate (PLA: 4.57+/-0.12 mmol x l(-1); CHO: 5.49+/-0.11 mmol x l(-1); P<0.01). The pattern of change in plasma cortisol, circulating lymphocyte count and saliva immunoglobulin A secretion did not differ between the carbohydrate and placebo trials. Blood neutrophil counts were 14% higher 1 h after the placebo trial than the carbohydrate trial (PLA: 4.8+/-0.5x10(9) cells x l(-1); CHO: 4.2+/-0.5x10(9) cells x l(-1); P = 0.06), but the treatment had no effect on the degranulation response of blood neutrophils stimulated by bacterial lipopolysaccharide. We conclude that, although previous studies have shown that carbohydrate feeding is effective in attenuating immune responses to prolonged continuous strenuous exercise, the same cannot be said for a soccer-specific intermittent exercise protocol. When overall exercise intensity is moderate, and changes in plasma glucose, cortisol and immune variables are relatively small, it would appear that carbohydrate ingestion has only a minimal influence on the immune response to exercise.

Adult↗
PubMed1999

The effects of high-intensity intermittent exercise on saliva IgA, total protein and alpha-amylase.

The aim of this study was to assess the effect of an acute bout of high-intensity intermittent exercise on saliva IgA concentration and alpha-amylase activity, since this type of training is commonly incorporated into the training programmes of endurance athletes and games players. Eight well-trained male games players took part in the study. They reported to the laboratory after an overnight fast and performed a 60-min cycle exercise task consisting of twenty 1-min periods at 100% VO2max, each separated by 2 min recovery at 30% VO2max. Unstimulated whole saliva was collected over a 5-min period into pre-weighed tubes and analysed for total protein, saliva IgA and alpha-amylase. The saliva flow rate ranged from 0.08 to 1.40 ml x min(-1) at rest and was not significantly affected by the exercise. The performance of the intermittent exercise bout did not affect the saliva IgA concentration, but caused a five-fold increase in alpha-amylase activity (P<0.01 compared with pre-exercise) and a three-fold increase in total protein concentration (P<0.01). These returned to pre-exercise values within 2.5 h post-exercise. It has been suggested that IgA concentration should be expressed as the ratio to total protein concentration, to correct for any concentrating effect due to evaporative loss of saliva water when breathing through the mouth (as in strenuous exercise). The present study clearly demonstrates that this is not appropriate, since there is an increase in salivary protein secretion rate immediately after exercise (571+/-77 microg x min(-1) compared with 218+/-71 microg x min(-1) pre-exercise; P<0.05). The increased saliva alpha-amylase activity after exercise may improve the protective effect of saliva, since this enzyme is known to inhibit bacterial attachment to oral surfaces. The saliva alpha-amylase secretion rate was lower immediately pre-exercise than at any other instant, which may have been due to anticipatory psychological stress, although the subjects were all familiar with interval exercise. This emphasizes the need for true resting non-stressed control conditions in future studies of the effects of exercise on saliva constituents.

Adult↗
PubMed1999

Nutritional aspects of immunosuppression in athletes.

The literature suggests that a heavy schedule of training and competition leads to immunosuppression in athletes, placing them at a greater risk of opportunistic infection. There are many factors which influence exercise-induced immunosuppression, and nutrition undoubtedly plays a critical role. Misinterpretation of published data and misleading media reports have lead many athletes to adopt an unbalanced dietary regimen in the belief that it holds the key to improved performance. Some sports have strict weight categories, whilst in others low body fat levels are considered to be necessary for optimal performance or seen as an aesthetic advantage. This leads some athletes to consume a diet extremely low in carbohydrate content which, whilst causing rapid weight loss, may have undesirable results which include placing the athlete at risk from several nutrient deficiencies. Complete avoidance of foods high in animal fat reduces the intake of protein and several fat-soluble vitamins. On the other hand, diets with a very high carbohydrate content are usually achieved at the expense of protein. In addition, anecdotal and media reports have often promoted the supposed performance benefits of certain vitamins and minerals, yet most athletes do not realise that micronutrient supplementation is only beneficial when correcting a deficiency, and to date there is little scientific evidence to substantiate claims that micronutrients act as an ergogenic aid. Moreover, excessive intakes of micronutrients can be toxic. Deficiencies or excesses of various dietary components can have a substantial impact on immune function and may further exacerbate the immunosuppression associated with heavy training loads. This review examines the role of nutrition in exercise-induced immunosuppression and the effect of both excessive and insufficient nutrient intake on immunocompetence. As much of the present literature concerning nutrition and immune function is based on studies with sedentary participants, the need for future research which directly investigates the relationship between exercise, training, immunity and nutrition is highlighted.

Diet↗
PubMed1998

The effects of high-intensity intermittent exercise on the plasma concentrations of glutamine and organic acids.

Glutamine is an essential substrate for the proper functioning of cells of the immune system. Falls in plasma glutamine concentration after exercise may have deleterious consequences for immune cell function and render the individual more susceptible to infection. The purpose of the present study was to examine changes in plasma glutamine concentration (measured using a validated enzymatic spectrophotometric method) following an acute bout of intermittent high-intensity exercise. Eight well-trained male games players took part in the study. Subjects reported to the laboratory following an overnight fast and performed a 1-h cycle exercise task consisting of 20 1-min periods at 100% maximal O2 consumption (VO2max) each separated by 2 min of recovery at 30% VO2max. Venous blood samples were taken before exercise and at 5 min, 1 h, 2.5 h, 5 h and 24 h post-exercise. Glutamine was measured by enzymatic spectrophotometric determination of the ammonia concentration before and after treatment of the plasma with glutaminase (EC 3.5.1.2). Plasma glutamine concentration did not fall in the immediate post-exercise period [pre-exercise 681 (23) microM compared with 663 (46) microM at 5 min post-exercise, mean (SEM)], but fell to 572 (35) microM at 5 h post-exercise (P < 0.05 compared with pre-exercise). Plasma lactate concentration rose to 8.8 (1.0) mM at the end of exercise and fell to 1.8 (0.4) mM at 1 h post-exercise, but plasma concentrations of free fatty acids and beta-hydroxybutyrate both rose substantially in the post-exercise period (to 240% and 400% of pre-exercise levels, respectively). The circulating leucocyte count increased significantly during exercise (P < 0.01), continued to increase in the hours following exercise and peaked at 2.5 h post-exercise (mainly due to a neutrophilia). The fall in the plasma glutamine concentration at 5 h post-exercise could be due to increased renal uptake of glutamine, which generally occurs in conditions of metabolic acidosis or due to a greater removal of glutamine from the plasma resulting from the elevated circulating leucocyte count.

3-Hydroxybutyric Acid↗
PubMed1998

The effect of severe eccentric exercise-induced muscle damage on plasma elastase, glutamine and zinc concentrations.

The aim of this study was to determine if severe exercise-induced muscle damage alters the plasma concentrations of glutamine and zinc. Changes in plasma concentrations of glutamine, zinc and polymorphonuclear elastase (an index of phagocytic cell activation) were examined for up to 10 days following eccentric exercise of the knee extensors of one leg in eight untrained subjects. The exercise bout consisted of 20 repetitions of electrically stimulated eccentric muscle actions on an isokinetic dynamometer. Subjects experienced severe muscle soreness and large increases in plasma creatine kinase activity indicative of muscle fibre damage. Peak soreness occurred at 2 days post-exercise and peak creatine kinase activity [21714 (6416) U x l(-1) mean (SEM)] occurred at 3 days post-exercise (P < 0.01 compared with pre-exercise). Plasma elastase concentration was increased at 3 days post-exercise compared with pre-exercise (P < 0.05), and is presumably indicative of ongoing phagocytic leucocyte infiltration and activation in the damaged muscles. There were no significant changes in plasma zinc and glutamine concentrations in the days following eccentric exercise. We conclude that exercise-induced muscle damage does not produce changes in plasma glutamine or zinc concentrations despite evidence of phagocytic neutrophil activation.

Adult↗
PubMed1998

The effect of exercising to exhaustion at different intensities on saliva immunoglobulin A, protein and electrolyte secretion.

The quality and quantity of saliva may be important in defending against pathogens transmitted via the buccal cavity. The aim of the present study was to examine the effect of cycling to exhaustion at moderate and high intensity on various salivary parameters and the time course of recovery. Eighteen male subjects of mixed physical fitness took part in the study. Subjects performed two bouts of exercise on separate occasions at least one week apart. Following an overnight fast, subjects cycled on an electrically braked cycle ergometer at a work rate equivalent to 80% VO2max until exhaustion. On another occasion they cycled on the same ergometer at 55% VO2max for 3 h or to fatigue (whichever was sooner). The order of the rides was randomised. Timed, unstimulated saliva samples were collected pre-exercise, during exercise, at cessation of exercise and at 1, 2.5, 5 and 24 h post-exercise. Saliva samples were analysed for IgA, total protein and osmolality. Saliva flow rate was significantly reduced by exercise (P < 0.01). Saliva IgA concentration, secretion rate and ratio to osmolality increased during exercise (P < 0.01). IgA to protein ratio did not change significantly during exercise. Since saliva protein secretion rate increased during exercise (P < 0.01) it appears that correcting for loss of saliva water by expressing IgA relative to protein is misleading. IgA secretion rate and IgA to osmolality ratio are more appropriate measures and neither parameter was lowered by exercise. The results of this study indicate that exercise may detrimentally affect the quantity of saliva produced, but not the quality of saliva. Furthermore, when exercise is to exhaustion, the intensity of the bout does not appear to influence the saliva response. Neither exercise protocol had any long term effect on saliva as all variables recovered within 1 h post-exercise.

Adult↗
PubMed1998

Glutamine, exercise and immune function. Links and possible mechanisms.

Glutamine is the most abundant free amino acid in human muscle and plasma and is utilised at high rates by rapidly dividing cells, including leucocytes, to provide energy and optimal conditions for nucleotide biosynthesis. As such, it is considered to be essential for proper immune function. During various catabolic states including surgical trauma, infection, starvation and prolonged exercise, glutamine homeostasis is placed under stress. Falls in the plasma glutamine level (normal range 500 to 750 mumol/L after an overnight fast) have been reported following endurance events and prolonged exercise. These levels remain unchanged or temporarily elevated after short term, high intensity exercise. Plasma glutamine has also been reported to fall in patients with untreated diabetes mellitus, in diet-induced metabolic acidosis and in the recovery period following high intensity intermittent exercise. Common factors among all these stress states are rises in the plasma concentrations of cortisol and glucagon and an increased tissue requirement for glutamine for gluconeogenesis. It is suggested that increased gluconeogenesis and associated increases in hepatic, gut and renal glutamine uptake account for the depletion of plasma glutamine in catabolic stress states, including prolonged exercise. The short term effects of exercise on the plasma glutamine level may be cumulative, since heavy training has been shown to result in low plasma glutamine levels (< 500 mumol/L) requiring long periods of recovery. Furthermore, athletes experiencing discomfort from the overtraining syndrome exhibit lower resting levels of plasma glutamine than active healthy controls. Therefore, physical activity directly affects the availability of glutamine to the leucocytes and thus may influence immune function. The utility of plasma glutamine level as a marker of overtraining has recently been highlighted, but a consensus has not yet been reached concerning the best method of determining the level. Since injury, infection, nutritional status and acute exercise can all influence plasma glutamine level, these factors must be controlled and/or taken into consideration if plasma glutamine is to prove a useful marker of impending overtraining.

Animals↗
PubMed1995

Ondansetron and opiate craving. A novel pharmacological approach to addiction.

BACKGROUND: Pharmacological approaches to opiate addiction have for the most part been limited to a role in detoxification. A high percentage of patients who complete detoxification programmes relapse. METHOD: In the present study, we used a simple laboratory method to investigate suggestions from preclinical studies that 5-(hydroxytryptamine) HT3 receptor antagonists have a role in the treatment of addiction. RESULTS: We showed that addicts stably maintained on methadone experienced significant craving, dysphoria, and withdrawal-like symptoms when exposed to a video containing drug-related cues. The craving was not lessened by treatment with the 5-HT3 receptor antagonist, ondansetron (4 mg orally). CONCLUSION: Our current findings do not support a role for 5-HT3 receptor agonists in the reduction of craving in opiate addicts.

Female↗
PubMed1994

Estimates of food and macronutrient intake in a random sample of Northern Ireland adolescents.

Estimates of food consumption and macronutrient intake were obtained from a randomly selected population sample (2%) of 1015 adolescents aged 12 and 15 years in Northern Ireland during the 1990/1991 school year. Dietary intake was assessed by diet history with photographic album to estimate portion size. Reported median energy intakes were 11.0 and 13.1 MJ/d for boys aged 12 and 15 years respectively and 9.2 and 9.1 MJ/d for girls of these ages. Protein, carbohydrate and total sugars intakes as a percentage of total energy varied little between the age and sex groups and were approximately 11, 49 and 20% respectively of daily total energy intakes. Median dietary fibre intakes were approximately 20 and 24 g/d for boys aged 12 and 15 years respectively and 18 and 19 g/d for girls of these ages. Major food sources of energy (as a percentage of total energy intakes) were bread and cereals (15-18%), cakes and biscuits (12-14%), chips and crisps (13-14%), dairy products (9-11%), meat and meat products (9-11%) and confectionery (9%). Fruit and vegetable intakes were low at about 2.5% and 1.5% respectively of total energy intakes. Median fat intakes were high at 39% of total daily energy intakes. Major food sources of fat as a percentage of total fat intakes were from the food groupings: chips and crisps (16-19%), meat and meat products (14-17%), fats and oils (14-16%), cakes and biscuits (13-16%) and dairy products (12-15%). Median intakes of saturated fatty acids were also high at approximately 15% of daily total energy intake while intakes of monounsaturated fatty acids averaged 12% of daily total energy intake. Median polyunsaturated fatty acid (PUFA) intakes were low, comprising 5.2 and 5.5% of daily total energy intake for boys aged 12 and 15 years respectively and were lower than the PUFA intakes (5.9 and 6.3% of daily total energy intake) for girls of these ages. About 1.3% for boys and 1.4% for girls of daily total energy intake was in the form of n-3 PUFA. Ca and Mg intakes were adequate for both sexes. Based on these results, some concern about the dietary habits and related health consequences in Northern Ireland adolescents appears justified.

Adolescent↗
PubMed1988

Self-esteem--a psychiatric view.

The literature relating to the acquisition, maintenance, and clinical significance of self-esteem reveals theoretical differences between earlier investigators. The nature of self-esteem remains controversial, and attention is drawn to some of the problems of construct validation and measurement. Despite the difficulties, self-esteem is a concept worthy of further pursuit. This will require a measuring instrument that captures the concept more effectively than those currently available.

Adult↗
PubMed1983

Clinical review of parenteral meptazinol.

The literature on the clinical use of parenteral meptazinol and its clinical pharmacology, is reviewed. Meptazinol is a centrally acting drug which produces analgesia of comparable intensity to the opiates, but there is evidence that this is more rapid in onset and of shorter duration. This potent analgesic effect is associated with a benign respiratory and cardiovascular profile. The incidence of "minor" side effects is similar to that seen following the opiates, except that central nervous system effects such as euphoria, dysphoria and hallucinations are rare. The route of metabolism of meptazinol makes it particularly suitable for use in obstetrics.

Absorption↗
PubMed1983

Reversibility of the analgesic effect of meptazinol in volunteers.

A double-blind randomized placebo-controlled study was carried out in 8 healthy volunteers to determine whether the analgesic and other actions of meptazinol could be reversed by naloxone or hyoscine. Heart rate, blood pressure, respiratory rate, pupil diameter, forearm ischaemic exercise tolerance and dental pain threshold were measured before and up to 45 minutes after intramuscular meptazinol 100 mg or placebo, when 'reversal' was attempted with intravenous naloxone 2 mg, hyoscine 1.6 mg or placebo. Meptazinol caused mild pupillary constriction which is unlikely to be clinically significant. Forearm ischaemic exercise tolerance failed to show any analgesic effect of meptazinol. Measurement of dental pain threshold strongly suggested reversal of meptazinol analgesia by naloxone but not by hyoscine, but inter-subject variation in analgesic response was great and these results require confirmation in a group pre-selected for consistent response.

Adult↗
PubMed1983

Preliminary clinical and pharmacokinetic experiences in the newborn when meptazinol is compared with pethidine as an obstetric analgesic.

Preliminary results on the disposition of meptazinol in the neonate are reviewed. Meptazinol has a half-life of 3.4 hours compared with 22.7 hours for pethidine. In a randomised double blind trial of 100 patients the depressant effects in the newborn of meptazinol and pethidine were compared. There was no difference in the Apgar scores at 1 and 3 minutes. Weight loss and the incidence of neonatal jaundice were less when mothers received meptazinol although these differences did not reach statistical significance. However, the number of infants considered fit for discharge by the 6th day was significantly greater in the meptazinol groups. In 43 cases transcutaneous monitoring of arterial PO2 was carried out for 30 minutes following delivery. Although the mean PaO2 was similar for meptazinol and pethidine, significant variations in the PaO2 of 2.0 kPa or greater and significant neonatal activity as judged by episodes of crying and movement, were recorded in the meptazinol group. The results of the trial suggest that meptazinol may have less depressant effects on the newborn, and may be preferable to pethidine as an obstetric analgesic.

Anesthesia, Obstetrical↗
PubMed1983

Administration of meptazinol to opiate-dependent patients.

A double blind comparison of the effect of intravenous meptazinol 100 mg and placebo was carried out on 8 opiate-dependent patients who were on a prolonged methadone withdrawal regime. Psychological and physiological measurements revealed no significant differences between meptazinol and placebo, and no patient reported pleasurable effects following meptazinol injection. These findings support the evidence from animal studies that meptazinol is unlikely to be abused by opiate addicts or to lead to dependence.

Adolescent↗