Existence Of Age Research Articles

Quantitative Assessment of Left and Right Atrial Strains Using Cardiovascular Magnetic Resonance Based Tissue Tracking.

Background: Left and right atrium (LA and RA) exert an essential and dynamic role in ventricular filling and hence affect heart performance. Strain quantification has been reported as a novel parameter to assess function. However, the assessment of bi-atrial strains with cardiovascular magnetic resonance (CMR) based techniques is still limited and gender- and age-specific normal values in a healthy population are missing.Methods: One hundred and fifty healthy volunteers (49.8 ± 17.3 years, 75 males) undergoing 1.5 Tesla CMR examination were retrospectively and consecutively recruited. LA and RA free wall (RAFW) radial and longitudinal strains (RS and LS) associated with atrial reservoir, conduit and booster pump functions were evaluated with CMR based tissue tracking (CMR-TT) technique.Results: The reservoir, conduit and pump LS resulted as 30.7 ± 10.2%, 19.5 ± 8.2%, 10.9 ± 3.7% for LA, and 52.2 ± 17.6%, 33.3 ± 14.2%, 19.1 ± 8.5% for RAFW, respectively. The amplitude of RA strains was significantly larger than that of LA strains, except for conduit RS. With the increase of age, the decrement of majority of reservoir and conduit strains were observed, while pump strains remained unaffected. Females presented with significantly larger RAFW strains compared with males, especially in the elderly. In addition to the positive correlation between atrial strains and emptying fraction, the negative correlation between atrial strains and volume index was also confirmed. Intra-observer reproducibility of LA strains was superior to RAFW strains (coefficient of variation: 10.12–17.04% vs. 10.80–27.36%, respectively), and the measurement of reservoir and conduit strains was more reproducible in comparison with pump strain.Conclusion: CMR-TT is a feasible and reproducible technique to quantify LA and RA strains and determine atrial phasic functions. The existence of age- and gender-related difference of strains suggests the necessity to establish specific normal values for individual populations.

Abstract B68: The influence of primary care on breast cancer outcomes among Medicare beneficiaries

Abstract Introduction: Primary care physicians (PCP) are integral in the early detection of cancer. Patients who are referred to a PCP, or who are assigned a PCP, are more likely to undergo most forms of cancer screening including mammograms and clinical breast examinations. PCPs may also ensure more timely diagnosis after screening abnormalities and prevent diagnostic delay. The Medicare-SEER database was used to explore the possibility of an association between primary care visits and breast cancer outcomes. With the usage of Medicare-SEER data, age, gender, and racial disparities exist. Methods: A retrospective cohort study design was used to evaluate 109,188 women that were Medicare beneficiaries and diagnosed with breast cancer in SEER registries during the years of 1994–2005. This data was used to analyze the association between primary care encounters and breast cancer outcomes. Health services related to cancer prevention and screening have been shown to occur in the ambulatory setting. The total number of ambulatory physician encounters and the percentage of such encounters with a primary care physician (PCP) were examined over a 24 month period before cancer diagnosis. Women with invasive cancers odds of late American Joint Commission on Cancer (AJCC) stage at diagnosis (stages III and IV vs. stages I and II) and survival (breast cancer specific and all cause) were examined using logistic regression and proportional hazards models respectively. Whether including non-invasive cancers (such as ductal carcinoma in situ, DCIS) would alter results and whether prior mammography was a potential mediator of associations was also explored. Results: Increasing numbers of ambulatory physician encounters were associated with improved breast cancer outcomes. In addition, subjects having between 40 and 60 percent of all encounters with PCPs were most likely to have had prior mammograms, least likely diagnosed at late stage, and to have lower breast cancer and all-cause mortality. Prior mammography mediated these associations in part but not completely. Results were unchanged when women with DCIS were included in the analysis. The average age of women involved in this study was 77 years old and 86 percent of the sample were non-minority. Conclusions: Although there is the existence of age, racial, and gender disparities because of the use of the Medicare-SEER data, using this information helps to identify better care tactics for aging women. Medicare beneficiaries with breast cancer had better outcomes if they had greater use of ambulatory care and care that was balanced between primary and specialty providers. These findings suggest adequate primary medical care may be an important factor in achieving optimal breast cancer outcomes. Citation Information: Cancer Epidemiol Biomarkers Prev 2011;20(10 Suppl):B68.

HAMILTON'S FORCES OF NATURAL SELECTION AFTER FORTY YEARS

In 1966, William D. Hamilton published a landmark paper in evolutionary biology: "The Moulding of Senescence by Natural Selection." It is now apparent that this article is as important as his better-known 1964 articles on kin selection. Not only did the 1966 article explain aging, it also supplied the basic scaling forces for natural selection over the entire life history. Like the Lorentz transformations of relativistic physics, Hamilton's Forces of Natural Selection provide an overarching framework for understanding the power of natural selection at early ages, the existence of aging, the timing of aging, the cessation of aging, and the timing of the cessation of aging. His twin Forces show that natural selection shapes survival and fecundity in different ways, so their evolution can be somewhat distinct. Hamilton's Forces also define the context in which genetic variation is shaped. The Forces of Natural Selection are readily manipulable using experimental evolution, allowing the deceleration or acceleration of aging, and the shifting of the transition ages between development, aging, and late life. For these reasons, evolutionary research on the demographic features of life history should be referred to as "Hamiltonian."

Secular Trends in Deaths From Cardiovascular Diseases

Although age-adjusted cardiovascular disease (CVD) mortality has declined over the past decades, controversies remain about whether this trend was similar across locations of death and disease categories and about the existence of age and sex disparities. We examined CVD mortality trends in Olmsted County, Minnesota, between 1979 and 2003 using the categories defined by the American Heart Association, including coronary heart disease (CHD), non-CHD diseases of the heart, and noncardiac circulatory diseases. Data on demographics, cause, and location of death of all 6378 residents who died of CVD were analyzed. Although decreases in the age-adjusted rates occurred in all groups, the magnitude of the decline varied widely. Lesser annual declines were noted in out-of-hospital than in-hospital deaths (1.8% versus 4.8%; P<0.001), in older than in younger persons (1.5% at age > or =85 years versus 3.9% for those < or =74 years of age; P<0.001), and in women relative to men (2.5% versus 3.3%; P=0.007). Furthermore, although CHD showed a marked annual decrease (3.3%), more modest decrements were found for non-CHD diseases of the heart (2.1%) and noncardiac circulatory diseases (2.4%) (P=0.02 and P=0.04 for the comparison with CHD decline, respectively). Over the past 25 years, CVD mortality declined markedly in the community, but there were large disparities in the magnitude of the decline, resulting in a shift in the distribution toward out-of-hospital and non-CHD deaths. Further reduction in CVD mortality will require strategies directed at elderly persons and women, in whom out-of-hospital rates have improved only minimally.

Effect of Advanced Glycation End Products on Lens Epithelial Cells in Vitro

The extended exposure of proteins to reducing sugars leads to nonenzymatic glycation with the accumulation of advanced glycation end products (AGEs). Long-lived proteins, such as collagen and crystallins, are subjected to this modification, and are implicated as causal factors in several diseases including diabetic complications, cataracts, and arteriosclerosis. One means through which AGEs modulate cellular interactions is via binding to specific receptors. In the current study, the existence of AGEs in human anterior polar lens capsules of cataracts was confirmed using a combination of dot-immunoblot and fluorescent detection. Human lens epithelial cells (LECs) attached to anterior lens capsules expressed mRNA for the receptor for AGEs (RAGE). The interaction of LECs with AGEs using bovine lens epithelial explants demonstrated that AGEs induced mRNAs and proteins of fibronectin, collagen type I, aberrant extracellular matrix proteins, and α-SMA, a specific marker for myofibroblastic cells. These findings suggest that AGEs may alter cellular functions which induce mRNAs and proteins associated with fibrosis in LECs.

Glauber Dynamics and Ageing

The Glauber dynamics of various models (REM-like trap models, Brownian motion, BM model, Ising chain and SK model) is analyzed in relation with the existence of ageing. From a finite size Glauber matrix, we calculate a time $\tau_w(N)$ after which the system has relaxed to the equilibrium state. The case of metastability is also discussed. If the only non zero overlaps between pure states are only self-overlaps (REM-like trap models, BM model), the existence or absence of ageing depends only on the behavior of the density of eigenvalues for small eigenvalues. We have carried out a detailed numerical and analytical analysis of the density of eigenvalues of the REM-like trap models. In this case, we show that the behavior of the density of eigenvalues for typical trap realizations is related to the spectral dimension of the equivalent random walk model.

Dietary effects on beef composition: III. Weight, composition and potassium–40 content of fat-free muscles

SUMMARYThe effects of several dietary regimens on the fat-free mass and the dry-matter, ash and potassium-40 content of selected bovine muscles were estimated. Muscle data from 104 half-sib Angus steers were secured at several stages of growth and after several feeding regimens. The results indicated that a hay diet, by comparison to a higher energy silage diet in the early feeding period (216–340 kg live weight), suppressed the fat-free weight, reduced the dry-matter content and increased the ash content of several muscles. These effects of early diet were reversed, however, when the animals were subsequently fed higher-energy rations and slaughtered at heavier weights (409 and 454 kg live weight). Data on potassium-40 gamma emissions by composite muscle samples confirmed the existence of age- or weight-associated decreases and suggested possible dietary influences on potassium levels in bovine muscles. The trends in these data indicated that low dietary energy (hay feeding) in the early feeding period delayed the decline in muscle potassium that normally accompanies maturation.