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PubMed2005

Reference values for methacholine reactivity (SAPALDIA study).

BACKGROUND: The distribution of airway responsiveness in a general population of non-smokers without respiratory symptoms has not been established, limiting its use in clinical and epidemiological practice. We derived reference equations depending on individual characteristics (i.e., sex, age, baseline lung function) for relevant percentiles of the methacholine two-point dose-response slope. METHODS: In a reference sample of 1567 adults of the SAPALDIA cross-sectional survey (1991), defined by excluding subjects with respiratory conditions, responsiveness during methacholine challenge was quantified by calculating the two-point dose-response slope (O'Connor). Weighted L1-regression was used to estimate reference equations for the 95th , 90th , 75th and 50th percentiles of the two-point slope. RESULTS: Reference equations for the 95th , 90th , 75th and 50th percentiles of the two-point slope were estimated using a model of the form a + b* Age + c* FEV1 + d* (FEV1)2 , where FEV1 corresponds to the pre-test (or baseline) level of FEV1. For the central half of the FEV1 distribution, we used a quadratic model to describe the dependence of methacholine slope on baseline FEV1. For the first and last quartiles of FEV1, a linear relation with FEV1 was assumed (i.e., d was set to 0). Sex was not a predictor term in this model. A negative linear association with slope was found for age. We provide an Excel file allowing calculation of the percentile of methacholine slope of a subject after introducing age--pre-test FEV1--and results of methacholine challenge of the subject. CONCLUSION: The present study provides equations for four relevant percentiles of methacholine two-point slope depending on age and baseline FEV1 as basic predictors in an adult reference population of non-obstructive and non-atopic persons. These equations may help clinicians and epidemiologists to better characterize individual or population airway responsiveness.

Age Distribution↗
PubMed1996

[Indicator of adrenoreceptors in cell membranes: reference values and informative validity in the assessment of the functional state of the cardiovascular system].

A new method of individual determination of sympathoadrenal activity (SAA) uses the parameter of beta-adrenoreception in cell membranes (beta-ARM) based on the erythrocyte model. Correlation of an individual reference beta-ARM value with specific features of hypertension states, and CVS responses to psychoemotional stress was studied. Described are the method, and normal distribution of individual beta-ARM values in healthy flyers, aviation students, non-flyers, and aviators with diagnosed the neurocirculatory dystonia of hypertensive type and patients with the hypertonic disease of 2nd stage (the overall numbers of subjects = 221). Another group of healthy subjects and patients with the hypertonic disease of 1st stage and different reference beta-ARM values (n = 39) participated in determination of HR and BP levels during the verbal count test. On the evidence of individual beta-ARM distribution in the test groups, the upper limit of the beta-ARM physiological norm (16.0 arbitrary units) was suggested to be a critical parameter in diagnosis of a hyperadrenergic state. Analysis of hemodynamics and the quality of verbal count during performance of a psychoemotional test by subjects with varying reference beta-ARM values revealed hyperreactive cardiovascular systems in and less successful fulfillment of the count test by subjects with high beta-ARM.

Adolescent↗
PubMed1984

[Parenteral administration of amino acids. Reference values--study technic--interpretation of the study results--amino acid pattern as a criterion of the regulation of homeostasis].

The concentrations of free amino acids were measured in lithium-heparinat-plasma with a standardized quality controlled analytical procedure in 200 healthy persons (blood donors). The distribution of the measured values were statistically evaluated in the total group and differentiated in the male and female subcollective. The absolute total concentrations of the free amino acids vary in a broad range between 1.7 and 4.4 mmol/l. This large range is also seen for the single amino acid. In a new system for documentation and interpretation of analytical data the measured values are collected and mean, median, standard deviation, mini-max-range and 95% confidence interval are automatically computed. On this basis of data a physiological reference range is defined. The broad variability of the absolute concentrations is not found in the relative composition of the pattern. The relations of the amino acid concentrations which are important for the quality of the cellular support are very constant. Their importance is caused by the fact that only few different transport systems exist for at least 20 amino acids, which means that the different amino acids are competing at the same system for cellular uptake. The essential of the results in this study is that the liver guarantees the constancy of the physiological pattern also in cases where the exogenous supply differs from the characteristics of elimination of the single amino acid from blood. Only when the oxidative capacity of the liver is insufficient as in pathological states like infections pathological concentrations are found. In these cases the true change is undiscovered when the absolute concentrations are considered, because the insufficient functions of the liver causes initially high total concentrations. For the interpretation of an analysis of amino acids in blood plasma two main criteria are necessary: the total concentration of amino acid characterizes the quantitative support while the concentration pattern determines the quality of the cellular uptake.

Adult↗
PubMedDate not supplied

[Bone density--reference values in German men. A study of the lumbar spine with the Lunar-DPX-densitometer].

UNLABELLED: The DXA-technique is a well established method to study bone mineral density (BMD). Until now there are no reliable reference data based on the male population of Germany. QUESTION: Are the data base, given by the manufacturer transferable to the male population in Germany? METHODS: So a cross sectional study based on 715 healthy males with German ethnic background (age 20-89) was carried out. Comparison was made to the ap spine reference data of northern Europe. RESULTS: The peak bone mass was 1,26 +/- 0,17 g/cm2 at the age of 20-24 years. After that the BMD decreases to the sixth decade (1,09 +/- 0,18 g/cm2), further on there is an increase to 1,18 +/- 0,21 g/cm2 in the ninth decade. CONCLUSION: Looking at a comparable Swedish study there are no significant differences, looking at a Finnish study there are statistically significant differences in the sixth decade (t = 3,246) and seventh decade (t = 2,413). The results of our study complete the data base until now, but one should be careful to transfer the data base provided by the manufacturer.

Absorptiometry, Photon↗
PubMedDate not supplied

Echocardiographic reference values for aortic root size: the Framingham Heart Study.

The objectives of this study were to develop sex-, age-, and body size-specific nomograms and partition values for upper and lower limits of M-mode echocardiographic aortic root measurements derived from a large population-based cohort. The study sample consisted of 1433 male and 1816 female participants in the Framingham Heart Study and Framingham Offspring Study who were normotensive and free of clinically apparent heart disease at the baseline examination. Aortic root measurements were obtained by M-mode echocardiography by a leading-edge to leading-edge technique. The relations of age and measures of body size with aortic root dimensions were evaluated with sex-specific correlations and multiple stepwise linear regression analyses. Age was the most important determinant of aortic root size in both men and women in the multivariable regression models. Models with age and body surface area yielded R2 values of 0.214 in men and 0.222 in women. Models with age and height yielded lower R2 values of 0.136 in men and 0.181 in women. Thus aortic root dimensions vary widely with the age, sex, and body size of individuals. Sex-specific reference nomograms of aortic root dimensions in relation to age and body size (body surface area or height) are presented to facilitate the detection of abnormalities of aortic root size.

Adult↗