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Age-dependent Differences (age-dependent + difference)
Selected AbstractsCauses and consequences of post-growth age-dependent differences in small intestine size in a migratory sandpiper (Calidris mauri, Western Sandpiper)FUNCTIONAL ECOLOGY, Issue 1 2006R. W. STEIN Summary 1Calidris mauri Cabanis (Western Sandpiper) exhibits a pronounced post-growth age-dependent difference in small intestine size during southward migration, such that the later-migrating juveniles have larger small intestines than do the adults. Potential causes and consequences of this age-dependent difference are examined. 2Premigrant juveniles of full structural size had small intestines that were 10% longer than those of the premigrant adults, even though the juveniles had not attained asymptotic body mass. The elongated small intestines of premigrant juveniles appear to be growth-related. 3Adults and juveniles exhibited parallel increases in intestinal length (7·0%) and circumference (9·5%) in association with the initiation of migration; these effects are consistent with migratory hyperphagia. 4Refuelling juveniles had small intestines that were 8·5% longer than those of the refuelling adults. Retaining an enlarged small intestine during migration confers increased digestive capacity to the juveniles, which may be under selection to minimize stopover duration. 5Refuelling juveniles had a higher prevalence of cestode infection than refuelling adults in one of two years, and the length-corrected mass of the small intestine was 9·7% heavier in infected individuals. Cestode infection may be an important determinant of migration-related mortality for juveniles, by compromising their health and increasing stopover duration. [source] Effect of age on anterior chamber angle configuration in Asians determined by anterior segment optical coherence tomography; clinic-based studyACTA OPHTHALMOLOGICA, Issue 6 2010Mi Hyun Cheon Acta Ophthalmol. 2010: 88: e205,e210 Abstract. Purpose:, To evaluate the distribution of anterior chamber angle (ACA) parameters and to assess association of these parameters with age in Asian subjects. Methods:, Four hundred and thirty-nine consecutive Korean subjects aged from 30 to 89 were enrolled from a university clinic. All participants were scanned using anterior segment optical coherence tomography (AS-OCT, Visante, version 2.0). We measured ACA parameters such as anterior chamber depth (ACD), angle opening distance at 500 and 750 ,m (AOD500,750), angle recess area at 500 and 750 ,m (ARA500,750), trabecular iris space area at 500 and 750 ,m (TISA500,750), and determined age-related changes in these parameters with use of a linear mixed effect model that adjusted for gender, axial length, intraocular pressure, and keratometry data. Slopes of ACA parameters as a function of age were determined. For various AS-OCT parameters, the normalized slope was calculated by dividing the slope by the mean value. Results:, All analysed ACA parameters decreased with age in both nasal and temporal quadrants. Axial length and keratometry data were significant covariates for ACA changes. The slopes of ACD were ,0.02396 mm/year, AOD500, ARA500, and TISA500 measured at the temporal angle were ,0.00634 mm/year, ,0.0019 mm2/year, and ,0.00177 mm2/year, respectively. There was no age-dependent difference in central corneal thickness (p value; 0.4597) Based on the normalized slopes, the AOD showed the steepest slope at both temporal and nasal sectors. Conclusion:, All ACA parameters assessed by AS-OCT, which accounted for other ocular biometric parameters, showed significant negative slopes with increasing age. These results should be considered when assessing changes in the anterior chamber over time. [source] Causes and consequences of post-growth age-dependent differences in small intestine size in a migratory sandpiper (Calidris mauri, Western Sandpiper)FUNCTIONAL ECOLOGY, Issue 1 2006R. W. STEIN Summary 1Calidris mauri Cabanis (Western Sandpiper) exhibits a pronounced post-growth age-dependent difference in small intestine size during southward migration, such that the later-migrating juveniles have larger small intestines than do the adults. Potential causes and consequences of this age-dependent difference are examined. 2Premigrant juveniles of full structural size had small intestines that were 10% longer than those of the premigrant adults, even though the juveniles had not attained asymptotic body mass. The elongated small intestines of premigrant juveniles appear to be growth-related. 3Adults and juveniles exhibited parallel increases in intestinal length (7·0%) and circumference (9·5%) in association with the initiation of migration; these effects are consistent with migratory hyperphagia. 4Refuelling juveniles had small intestines that were 8·5% longer than those of the refuelling adults. Retaining an enlarged small intestine during migration confers increased digestive capacity to the juveniles, which may be under selection to minimize stopover duration. 5Refuelling juveniles had a higher prevalence of cestode infection than refuelling adults in one of two years, and the length-corrected mass of the small intestine was 9·7% heavier in infected individuals. Cestode infection may be an important determinant of migration-related mortality for juveniles, by compromising their health and increasing stopover duration. [source] Age-related plasma reference ranges for two heparin-binding proteins , vitronectin and platelet factor 4INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 6 2009F. NEWALL Summary This study was conducted to establish age-related reference ranges for two heparin-binding proteins , vitronectin and platelet factor 4 (PF4) , and to determine if the quantitative values of these proteins may contribute to the reported age-dependent effect of unfractionated heparin (UFH). Plasma samples were obtained from healthy children aged between 1 month and 16 years and from healthy adult volunteers. Two commercial kits were used to measure plasma vitronectin and PF4 levels. Results were reported as mean and boundaries including 95% of the population. Plasma vitronectin levels for children aged 1,5 years were significantly higher compared with adults. Plasma PF4 levels for infants <1 year of age were significantly lower compared with adults. The differences between reference values for both proteins in all other age-groups were not statistically significant. This study for the first time has established age-related reference ranges for vitronectin and PF4. In establishing these ranges, the quantitative values of these proteins do not appear to be the major contributory cause for the age-dependent variation in UFH effect. Future studies are required to evaluate the possible impact of age-dependent differences in binding between heparin-binding proteins and UFH. [source] Aging alters regional multichemical profile of the human brain: an in vivo1H-MRS study of young versus middle-aged subjectsJOURNAL OF NEUROCHEMISTRY, Issue 2 2001Igor D. Grachev Age-related differences in the multichemical proton magnetic resonance spectroscopy (1H-MRS) profile of the human brain have been reported for several age groups, and most consistently for ages from neonates to 16-year-olds. Our recent 1H-MRS study demonstrated a significant age-related increase of total chemical concentration (relative to creatine) in the prefrontal and sensorimotor cortices within young adulthood (19,31-year-olds). In the present study we test the hypothesis that the level of brain chemicals in the same cortices, which show increased chemical levels during normal development, are reduced with normal aging after young adulthood. The multichemical 1H-MRS profile of the brain was compared between 19 young and 16 middle-aged normal subjects across multiple brain regions for all chemicals of 1H-MRS spectra. Chemical concentrations were measured relative to creatine. Over all age groups the total relative chemical concentration was highest in the prefrontal cortex. Middle-aged subjects demonstrated a significant decrease of total relative chemical concentration in the dorsolateral prefrontal (F = 54.8, p < 10,7, anova), orbital frontal (F = 3.7, p < 0.05) and sensorimotor (F = 15.1, p < 0.0001) cortices, as compared with younger age. Other brain regions showed no age-dependent differences. The results indicate that normal aging alters multichemical 1H-MRS profile of the human brain and that these changes are region-specific, with the largest changes occuring in the dorsolateral prefrontal cortex. These findings provide evidence that the processes of neuronal maturation of the human brain, and neurotransmitters and other chemical changes as the marker of these neuronal changes are almost finished by young adulthood and then reduced during normal aging toward middle age period of life. The present data also support the notion of heterochronic regressive changes of the aging human brain, where the multichemical brain regional profile seems to inversely recapitulate cortical chemical maturation within normal development. [source] Contact calls of common marmosets (Callithrix jacchus): influence of age of caller on antiphonal calling and other vocal responsesAMERICAN JOURNAL OF PRIMATOLOGY, Issue 2 2009H.-C. Chen Abstract Marmosets, as do many other primates, live in forest environments, are group living and constantly at risk of predation. Retaining contact with one another is therefore a matter of survival. We ask here whether their contact calls (phee and twitter vocalizations) are in some way ordered acoustically by sex or age and whether the calls of older marmosets elicit different responses than those of younger marmosets. In our study, marmosets (2,14 years) were visually isolated from conspecifics and the vocal responses to each isolated caller by other marmosets in the colony were recorded. Vocal responses to phee calls largely consisted of phee calls and, less commonly, twitter calls. No differences between the responses to calls by males and females were apparent. However, we found a strong positive and significant correlation between the caller's age and the percentage of its phee calls receiving a phee response, and a significant negative correlation between the caller's age and the percentage of its phee calls receiving a twitter response. The older the marmoset, the more antiphonal calling occurred. Two-syllable phee calls were emitted more often by older marmosets (10,14 years) than by younger ones (2,6 years). Hence, we have found age-dependent differences in phee-call production and a consistent change in the response received across the adult life-span. This age-dependent effect was independent of kinship relations. This is the first evidence that marmosets distinguish age by vocal parameters alone and make social decisions based on age. Am. J. Primatol. 71:165,170, 2009. © 2008 Wiley-Liss, Inc. [source] | |||||||||||||