			Home About us Contact

Longitudinal Trends (longitudinal + trend)

Distribution by Scientific Domains

Medical Sciences	50%

Selected Abstracts

Longitudinal trends of total and allergen-specific IgE throughout childhood

ALLERGY, Issue 7 2009
P. M. Matricardi
Background:, The development and the quantitative relationship between allergen-specific IgE (S-IgE) responses and total IgE (T-IgE), during childhood and adolescence have not been described and understood in detail. The objective of this study was to describe and compare the longitudinal trends of serum levels of S-IgE and T-IgE during childhood. Methods:, We analysed data from participants in the MAS birth cohort study at 2, 5, 7 and 10 years of age (n = 273) and at 1, 3, 5, 6, 7, 10 and 13 years (n = 84). Total-IgE and the overall level of specific-IgE against nine locally relevant airborne and food allergens were determined by FEIA (ImmunoCAP). Allergic rhino-conjunctivitis and asthma were ascertained by questionnaires. Results:, Longitudinal patterns of T-IgE levels from age 1 to 13 years were highly heterogeneous (declining, flat or increasing with different profiles). From 5 years of age, logarithmic (log10) transformed values of T-IgE and of S-IgE levels tend to follow a parallel trend, so that their relation remained constant throughout school age. A flat trend of T-IgE vs a constantly increasing trend of T-IgE was associated with a low or, respectively, high rate of wheezing at 13 years of age. Conclusions:, Beginning at the age of 5 years, total serum IgE levels in children from an industrialized country evolved in parallel with overall S-IgE levels. Therefore, variations in T-IgE levels at school age closely reflect variations in overall S-IgE levels. Further studies are required to strengthen the biological and clinical implication of this novel finding. [source]

Adaptation to the laboratory environment in Drosophila subobscura

JOURNAL OF EVOLUTIONARY BIOLOGY, Issue 1 2000
Matos
Adaptation to a novel environment is expected to have a number of features. Among these is a temporal increase in fitness and some or all of its components. It is also expected that additive genetic variances for these fitness characters will fall. Finally, it is expected that at least some additive genetic correlations will decrease, from positive toward negative values. In a study of several life-history variables in a Drosophila subobscura population sampled from the wild and then cultured in the laboratory, we did not find any such longitudinal trends over the first 29 generations. However, a temporal comparison (over 14 generations) of the later generations of this laboratory-adapted population with a new population, derived from a more recent wild-caught sample, indicated clearly that laboratory adaptation was nonetheless occurring. This study suggests the need for extensive replication and control in studies of the features of adaptation to a novel environment. [source]

Nested Markov Compliance Class Model in the Presence of Time-Varying Noncompliance

BIOMETRICS, Issue 2 2009
Julia Y. Lin
Summary We consider a Markov structure for partially unobserved time-varying compliance classes in the Imbens,Rubin (1997, The Annals of Statistics25, 305,327) compliance model framework. The context is a longitudinal randomized intervention study where subjects are randomized once at baseline, outcomes and patient adherence are measured at multiple follow-ups, and patient adherence to their randomized treatment could vary over time. We propose a nested latent compliance class model where we use time-invariant subject-specific compliance principal strata to summarize longitudinal trends of subject-specific time-varying compliance patterns. The principal strata are formed using Markov models that relate current compliance behavior to compliance history. Treatment effects are estimated as intent-to-treat effects within the compliance principal strata. [source]

Ultrasonically measured horizontal eye muscle thickness in thyroid associated orbitopathy: cross-sectional and longitudinal aspects in a Danish series

ACTA OPHTHALMOLOGICA, Issue 2 2003
Hans C. Fledelius
Abstract. Purpose:, To analyse horizontal extraocular muscle findings by ultrasound and exophthalmometry in a tertiary endocrinology centre series of patients with thyroid associated orbitopathy (TAO). Methods:, The 90 thyroid patients included underwent ultrasonic measurement of horizontal eye muscle thickness by a B-scan based technique carried out in addition to their general ophthalmic evaluation. As an indicator of mainly advanced TAO, longterm prednisone or cyclosporine A was given to many of the patients, and drug-resistant visual loss indicated decompression surgery in four of the 90 patients. Thirty-four patients underwent repeated muscle recordings over 15,49 months; this allowed for cross-sectional analysis and the outlining of longitudinal trends. Results and Conclusions:, (A) Although marginally overlapping, all four muscle groups were significantly thicker in the study group than in normal control subjects. The mean of the sum of all four muscles was 16.8 mm (range 13.6,21.7 mm) in the control group versus 22.6 mm (range 15.5,36.4 mm) in the thyroid group. (B) Using the clinical NOSPECS grading, more advanced eye involvement was found to generally result in a higher exophthalmometric measurement of protrusion and eye muscle thickness. However, slender rectus muscles and/or normal exophthalmometric values might occur even in advanced orbitopathy. (C) Over a period of 2,4 years, only a few of 34 patients with satisfactory serial ultrasonic measurements returned to their premorbid ophthalmic status. Typically, the extraocular muscles kept their abnormal size after having become clinically quiescent (fibrotic). (D) We found no safe indication regarding disease stage, active or late, from the ultrasonic appearance of the muscle tissue. (E) Discrepancies between various normative eye muscle studies are discussed with regard to computer tomography and magnetic resonance imaging. [source]