Die Wirkung länger dauernder Hydrochlorothiazid-Gaben auf die Plasma-Renin-Aktivität und die Aldosteron-Exkretionsrate bei Normalpersonen

Zusammenfassung Die Wirkung von Hydrochlorothiazid auf die Plasma-Renin-Aktivität (PRA) und die Aldosteron-Exkretionsrate (AER) wird bei 10 Normalpersonen untersucht. Gleichzeitig werden Bestimmungen der Serum- und Urinelektrolyte, des Hämatokrits und der Flüssigkeitsbilanz durchgeführt. In derjenigen Gruppe, die während 7 Tagen täglich 50 mg Hydrochlorothiazid (Esidrex®) erhielt, steigen die PRA am 2. und 4. Tag und die AER am 3. Tag nach Beginn der Diuretikagabe signifikant an, während am 6. bzw. am 7. Tag ein Abfall beider Parameter zur Norm einsetzt. Wesentliche Änderungen der Serumelektrolyte und des Hämatokrits werden nicht registriert. Die Stimulation des Renin-Angiotensin-Aldosteron-Systems (RAAS) kann mit einer erhöhten Natriurese und Diurese korreliert werden. Die Kaliurese steigt ebenfalls deutlich an, so daß der Na/K-Quotient im Urin unter 1 abfällt.In derjenigen Gruppe, die während 6 Wochen täglich 50 mg Hydrochlorothiazid erhielt, werden nach 2, 4 und 6 Wochen der Diuretikaverabreichung keine signifikanten Veränderungen der PRA, AER, Serumelektrolyte und des Hämatokrits festgestellt. Es entwickelt sich demnach unter längerdauernden Saluretikagaben kein sekundärer Hyperaldosteronismus.Die Wirkung sowohl einer Natriumrestriktion als auch einer saluretikainduzierten Natriumexkretion auf das RAAS wird besprochen. Schließlich werden die Möglichkeiten diskutiert, die einen Rückgang der Stimulation des RAAS trotz andauernder Diuretikagaben bewirken können.

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Summary The effect of hydrochlorothiazide on plasma renin activity (PRA) and aldosterone excretion rate (AER) were examined in 10 normal persons. At the same time, determinations of serum and urine electrolytes, of hematocrit and of fluid balance were carried out. In that group which recieved 50 mg hydrochlorothiazide (Esidrex®) daily for 7 days, the PRA rose significantly on the 2nd and 4th day and the AER on the 3rd day after the beginning of diuretic treatment. A decline to normal in both parameters set in on the 6th and 7th day, respectively. Considerable changes in serum electrolytes and hematocrit were not registered. The stimulation of the renin-angiotensin-aldosterone system (RAAS) could be correlated with elevated natriuresis and diuresis. Kaliuresis rose considerably as well so that the Na/K quotient in urine fell under 1.In that group which recieved 50 mg hydrochlorothiazide daily for a period of 6 weeks, no significant changes were noticed in PRA, AER, serum electrolytes or hematocrit after 2, 4 and 6 weeks of diuretic treatment. There was no development of secondary hyperaldosteronism under extended saluretic treatment.The effect of sodium restriction as well as saluretica-induced sodium excretion on the RAAS is discussed. Finally, the possibilities are discussed which can cause a retreat in stimulation of the RAAS despite extended treatment with diuretics.

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Diese Arbeit wurde durch die Hilfe des Schweizerischen Nationalfonds zur Förderung der wissenschaftlichen Forschung und der Stiftung zur wissenschaftlichen Forschung an der Universität Zürich ermöglicht.     

Working conditions and health behavior as causes of educational inequalities in self-rated health: an inverse odds weighting approach

Objective:Using a novel mediation method that presents unbiased results even in the presence of exposure–mediator interactions, this study estimated the extent to which working conditions and health behaviors contribute to educational inequalities in self-rated health in the workforce.Methods:Respondents of the longitudinal Survey of Health, Ageing, and Retirement in Europe (SHARE) in 16 countries were selected, aged 50–64 years, in paid employment at baseline and with information on education and self-rated health (N=15 028). Education, health behaviors [including body mass index (BMI)] and working conditions were measured at baseline and self-rated health at baseline and two-year follow-up. Causal mediation analysis with inverse odds weighting was used to estimate the total effect of education on self-rated health, decomposed into a natural direct effect (NDE) and natural indirect effect (NIE).Results:Lower educated workers were more likely to perceive their health as poor than higher educated workers [relative risk (RR) 1.48, 95% confidence interval (CI) 1.37–1.60]. They were also more likely to have unfavorable working conditions and unhealthy behaviors, except for alcohol consumption. When all working conditions were included, the remaining NDE was RR 1.30 (95% CI 1.15–1.44). When BMI and health behaviors were included, the remaining NDE was RR 1.40 (95% CI 1.27–1.54). Working conditions explained 38% and health behaviors and BMI explained 16% of educational inequalities in health. Including all mediators explained 64% of educational inequalities in self-rated health.Conclusions:Working conditions and health behaviors explain over half of the educational inequalities in self-rated health. To reduce health inequalities, improving working conditions seems to be more important than introducing health promotion programs in the workforce.     

Auditing paediatric diabetes care and the impact of a specialist nurse trained in paediatric diabetes

AIMS: To define outcome measures for auditing the clinical care of children and adolescents with insulin dependent diabetes mellitus (IDDM) and to assess the benefit of appointing a dedicated paediatric trained diabetes specialist nurse (PDSN). METHODS: Retrospective analysis of medical notes and hospital records. Glycaemic control, growth, weight gain, microvascular complications, school absence, and the proportion of children undergoing an annual clinical review and diabetes education session were assessed. The effect of the appointment of a PDSN on the frequency of hospital admission, length of inpatient stay, and outpatient attendance was evaluated. RESULTS: Children with IDDM were of normal height and grew well for three years after diagnosis, but grew suboptimally thereafter. Weight gain was above average every year after diagnosis. Glycaemic control was poor at all ages with only 16% of children having an acceptable glycated haemoglobin. Eighty five per cent of patients underwent a formal annual clinical review, of whom 16% had background retinopathy and 20% microalbuminuria in one or more samples. After appointing the PDSN the median length of hospital stay for newly diagnosed patients decreased from five days to one day, with 10 of 24 children not admitted. None of the latter was admitted during the next year. There was no evidence of the PDSN affecting the frequency of readmission or length of stay of children with established IDDM. Non-attendance at the outpatient clinic was reduced from a median of 19 to 10%. CONCLUSIONS: Outcome measures for evaluating the care of children with IDDM can be defined and evaluated. Specialist nursing support markedly reduces the length of hospital stay of newly diagnosed patients without sacrificing the quality of care.     

Inflammatory bowel disease and predisposition to osteopenia

The prevalence of osteopenia in children with inflammatory bowel disease (IBD) is unknown. The effect of nutritional state, disease activity, and steroid therapy on bone mineral content (BMC) of whole body, lumbar spine, and left femoral neck measured by dual energy x ray absorptiometry in 32 children with IBD was assessed by comparison with 58 healthy local school children. Using the control data, a predicted BMC was calculated taking into account bone area, age, height, weight, and pubertal stage. The measured BMC in children with IBD was expressed as a percentage of this predicted value (% BMC). Mean (SD) % BMC was significantly reduced for the whole body and left femoral neck in the children with IBD (97.0 (4.5)% and 93.1 (12.0)% respectively, p < 0.05). Of the children with IBD, 41% had a % BMC less than 1 SD below the mean for the whole body and 47% at the femoral neck. Reduction in % BMC was associated with steroid usage but not with the magnitude of steroid dose, disease activity, or biochemical markers of bone metabolism. In conclusion, osteopenia is relatively common in childhood IBD and may be partly related to the previous use of steroids.     

Phenotypic diversity in siblings with partial androgen insensitivity syndrome

The androgen insensitivity syndrome is a heterogeneous disorder with a wide spectrum of phenotypic abnormalities, ranging from complete female to ambiguous forms that more closely resemble males. The primary abnormality is a defective androgen receptor protein due to a mutation of the androgen receptor gene. This prevents normal androgen action and thus leads to impaired virilisation. A point mutation of the androgen receptor gene affecting two siblings with partial androgen insensitivity syndrome is described. One had cliteromegaly and labial fusion and was raised as a girl, whereas the other sibling had micropenis and penoscrotal hypospadias and was raised as a boy. Both were shown to have the arginine 840 to cysteine mutation. The phenotypic variation in this family is thus dependent on factors other than abnormalities of the androgen receptor gene alone.     

Immunobiology of T helper cells and antigen-presenting cells in autoimmune thrombocytopenic purpura (ITP)

Autoimmune thrombocytopenic purpura (AITP) is a bleeding disease in which autoantibodies are directed against the individual's own platelets, resulting in enhanced Fc-mediated platelet destruction by macrophages in the reticuloendothelial system. Most research in AITP has focused on characterization of the autoantibodies, while little has been devoted to the cellular immune mechanisms leading to autoantibody production. This report summarizes the current state of the literature and argues that enhanced T helper cell/antigen-presenting cell interactions in patients with AITP are the primary stimulus for the development of antiplatelet autoantibody production. Understanding these events is important for eventually identifying disease-initiating platelet autoantigens and ultimately developing specific immunotherapies for AITP.     

Analytical and simulation methods for estimating the potential predictive ability of genetic profiling: a comparison of methods and results

Various modeling methods have been proposed to estimate the potential predictive ability of polygenic risk variants that predispose to various common diseases. However, it is unknown whether differences between them affect their conclusions on predictive ability. We reviewed input parameters, assumptions and output of the five most common methods and compared their estimates of the area under the receiver operating characteristic (ROC) curve (AUC) using hypothetical data representing effect sizes and frequencies of genetic variants, population disease risk and number of variants. To assess the accuracy of the estimated AUCs, we aimed to reproduce the AUCs of published empirical studies. All methods assumed that the combined effect of genetic variants on disease risk followed a multiplicative risk model of independent genetic effects, but they either assumed per allele, per genotype or dominant/recessive effects for the genetic variants. Modeling strategy and input parameters differed. Methods used simulation analysis or analytical formulas with effect sizes quantified by odds ratios (ORs) or relative risks. Estimated AUC values were similar for lower ORs (<1.2). When AUCs were larger (>0.7) due to variants with strong effects, differences in estimated AUCs between methods increased. The simulation methods accurately reproduced the AUC values of empirical studies, but the analytical methods did not. We conclude that despite differences in input parameters, the modeling methods estimate similar AUC for realistic values of the ORs. When one or more variants have stronger effects and AUC values are higher, the simulation methods tend to be more accurate.