The effect on immunity of long-term intensive training in elite swimmers

The impact of long-term training on systemic and mucosal immunity was assessed prospectively in a cohort of elite swimmers over a 7-month training season in preparation for national championships. The results indicated significant suppression (P < 0.05) of serum IgA. IgG and IgM and salivary IgA concentration in athletes associated with long-term training at an intensive level. There was also a trend towards lower IgG2 subclass levels in serum in athletes compared with controls (P= 0.07). There were no significant changes in numbers or percentages of B or T cell subsets, but there was a significant fall in natural killer (NK) cell numbers and percentages in athletes over the training season (P < 0.05). After individual training sessions there was a significant decrease in salivary IgA levels for athletes compared with controls (P= 0.02). In athletes there was a downward trend in salivary IgA levels over the 7-month training period in both the pre-exercise (P= 0.06) and post-exercise samples (P= 0.04). There were no significant trends in salivary IgG levels over the study period in either athletes or controls. The only significant change in salivary IgM levels was an increase in detection rate in the pre-competition phase in athletes (P= 0.03). The study suggests that training of elite athletes at an intensive level over both short- and long-time frames suppresses both systemic and mucosal immunity. Protracted immune suppression linked with prolonged training may determine susceptibility to infection, particularly at times of major competitions.     

Placebo Controlled Trial of Systemic Corticosteroids in Acute Childhood Asthma

ABSTRACT. In a randomised controlled trial 38 asthmatic children aged 2-11 yr who had not received regular oral or inhaled steroids during the previous year, were treated with a standard regime of nebulised salbutamol and intravenous aminophylline plus either hydrocortisone and oral prednisolone for 5 days, or placebo. The children were observed throughout their hospital stay and for 3 months afterwards. There was a greater fall in heart rates in the steroid treated group on the second day of treatment (mean diff. 16 beats/min) and at discharge (mean diff. 13 beats/min); p < 0.025. Peak Expiratory Flow Rates recorded in 26 children, 13 in each group, showed more improvement on day 2 in those given steroids (mean diff 16% predicted); p < 0.05. This difference was not apparent at discharge but 9 children treated with steroids were clinically wheeze-free when they left hospital compared with 3 in the placebo group, p < 0.05. There were no differences in respiratory rate, pulsus paradoxus and arterial oxygen saturation. Trends in duration of hospital stay and relapse rate during the succeeding 3 months favoured active treatment. These findings support the use of systemic corticosteroids in addition to high dose bronchodilators to treat 'non steroid dependent' children hospitalised with acute severe asthma.     

A clinical evaluation in children of the Pharmacia ImmunoCAP system for inhalant allergens

Background The Pharmacia ImmunoCAP system (CAP) for assaying serum IgE specific antibodies was evaluated in a clinical setting against skin-prick test (SPT) perfonncd using Dome/Hollister-Steir allergen extracts. The five cotnmon inhalant allergens D. pteronyssinus. D. farinae, mould mix, grass mix and cat epithelium were tested concurrently by both methods in 167 children aged 7.5–12 years. The specific SPT for D. pteronyssinus and D. farinae were also tested against the CAP house dust mite (HDM) mix. Objective The purpose of the study was to determine the sensitivity and specificity of the Pharmacia ImmunoCAP system Tor detecting serum IgE specific antibodies to inhalant allergens in a clinical setting, using the SPT result as the ‘gold standard’. Methods The SPTs were performed using Dome/Hollister-Steir allergen extracts. The serum IgE specific antibodies were quantitated using the radioimmunoassay version of the Pharmacia ImmunoCAP system. A history of allergic disease was assessed using a validated questionnaire. Results SPT gave more positive reactions than CAP with the exception of cat epithelium. The concordance between SPT and CAP results was 91% over all the tests. The concordance with SPT was slightly higher for the specific CAP for D. pteronyssinus and D. farinae (93% and 95% respectively) than for the CAP HDM mix (86% and 90% respectively). There was a higher proportion of positive results for both SPT and CAP in the 115 children defined as having a history of allergic disease. Using SPT defined allergy as the gold standard, the sensitivity of the CAP system was 87% for the two specific house dust mites but was lower for cat epithelium (67%), mould mix (59%) and grass mix (46%). The sensitivity of the CAP system improved for D. pteronyssinus (96%) and the HDM mix (91%) when tested in subjects defined as having a history of allergy associated disease. The specificity of the CAP system showed less variation between allergens and ranged from 90–99%. Conclusion The results of this study of children aged 7.5–12 years demonstrate that, for the inhalent allergens tested, the Pharmacia ImmunoCAP system perfoms well in the setting of known allergic disease.     

Body build and the desire for slenderness in young people

The median weight-for-height of young people in Brisbane are below the 'standard' values. In most groups the weight-for-height are symmetrically distributed, suggesting that this is the range of normal variation. Only among girls aged 15-19 years was there an excess of 'obese' subjects.
Almost all girls and young women say they want to lose weight, even though many are already well below the 'standard'. This trend is also present, but is less marked, among boys and young men. In these young people the desire for slenderness is causing unhappiness that seems out of proportion to the possible benefits of change. Health professionals should encourage a more balanced attitude to physiological variations in weight-for-height among young people.     

The Variability of Immunoglobulins and Albumin in Salivary Secretions of Children

The variation of concentrations of immunoglobulins and albumin in consecutive daily collections of saliva was studied in 33 infants, aged 6 months to 5 years, for periods ranging from 16 to 26 days. The concentration and the within-child variability of IgA and albumin and the detection of IgG and IgM in saliva increased with age. Between-child variances were greater than the within-child variances by a factor of 2.8 for log (IgA) and 1.3 for log (albumin). The geometric mean IgA levels were consistently higher and IgG was detected more frequently during upper respiratory tract infections compared with periods of non-infection. There were no changes in albumin levels between infection and non-infection periods, suggesting a local immune response rather than serum leakage. There were significant within-child correlations (autocorrelations) between levels of IgA in saliva collected on consecutive days and samples collected up to 3 days apart. The autocorrelations between levels of albumin were significant for samples collected up to 2 days apart. The autocorrelation for IgA was significantly greater during infection periods compared with non-infection periods for samples collected on consecutive days.     

General practitioner and paediatrician self-reported capacity for the diagnosis and management of childhood and adolescent overweight and obesity

Aim:  The purpose of the present study was to assess and document the self-reported capacity, knowledge, skill and confidence of Central Coast general practitioners and paediatricians in the identification and management of overweight and obesity in children and adolescents, to investigate the barriers they experience in this area of practice and to consider how the local public sector nutrition service may assist.
Methods:  Forty general practitioners and three paediatricians were interviewed using a semistructured purpose-designed questionnaire.
Results:  Most participating doctors perceived that public sector dietitians are not available to assist them in managing overweight and obese paediatric patients. Few (23%) doctors reported using published guidelines and most reported significant barriers limiting their capacity to identify and manage this patient group effectively. All doctors identified at least one way in which the public health system can better support doctors in this role.
Conclusions:  The findings suggest that many doctors may benefit from increased training and a health system that better remunerates them for the time investment needed to provide management consistent with best practice. Reorientation of local public sector nutrition services may also provide them with better support when managing overweight and obese paediatric clients. Future research should examine the actual practices of doctors and how public sector dietitians can best communicate and interact with them to facilitate effective management of these patients.     

Effect of acute bile acid pool depletion on total and ionized calcium concentrations in human bile*

Abstract. Although calcium salts are important components of gallstones, there are few data on the total and ionized calcium content of human bile. Therefore, in 14 fasting T-tube patients studied 7–11 days after cholecystectomy, we measured bile flow, bile acid [BA], total [Ca_TOt] and free ionized [Ca⁺⁺] calcium concentrations, in 20–30 min bile collections during acute BA pool depletion induced by 6–8 h of continuous bile drainage. During washout of the BA pool there were parallel falls in bile flow, BA output and total calcium output (correlation coefficients ranging from 0.59 to 0.99; P< 0.02–0.001). In 12 of the 14 patients, [Ca_TOT] also fell (from 1.84 ± 0.29 to l.32 ± 0.34 mmol L^-1) in parallel with [BA] (from 34.0 ± 14.0 to 8.2 ± 8.0 mmol L^-1; r= 0.75–0.98; P<0.005). In contrast, biliary [Ca⁺⁺] remained virtually unchanged. These data suggest that the BAs are linked to the bound, rather than to the free, ionized, fraction of biliary calcium, which is consistent with in vivo calcium binding by BAs. A model is proposed in which BA-induced biliary calcium secretion results from (i) bile acid-induced water flow via solvent drag; and (ii) calcium binding in the bile canaliculus by bile acids, which induces paracellular diffusion of Ca⁺⁺, thereby maintaining [Ca⁺⁺] independent of [BA].