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OPEN ACCESS PLUS
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Contents
Pp. 127 - 137
Gwendolen E. Haley, Frederique Berteau-Pavy, Byung Parkv, Jacob Raber and Byung Park
[Open Access Plus] |
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Previously we reported that Apolipoprotein E (ApoE) ε4 negatively affects performance in the novel-image-novel- location (NINL) object recognition test in healthy non-demented elderly human study participants. In this study, the participants were invited to return for testing sessions 6 and 18 months after the baseline session. Using a longitudinal study design, effects of ε4 on NINL test performance were assessed in study “dropouts”, participants that did not return for the second and/or third session(s), and “finishers”, participants that returned for all sessions. There were effects of ε4 on dropout rates and NINL total scores as well as sub-scores in both dropouts and finishers. NINL total score was a predictor of ε4 participant dropout. Compared to non-ε4 dropouts, ε4 dropouts had lower NINL scores. In contrast, ε4 finishers had higher NINL scores than non-ε4 finishers. Thus, the NINL test could be a valuable tool in detecting preclinical signs of age-related cognitive impairments, particularly those associated with ε4 risk.
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Pp. 166 - 168
Sven Kurbel
[Open Access Plus] |
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The left ventricle thickness is a limiting factor of optimal heart size and strength. Due to disappearance of all the features compromising left ventricular compliance, mammalian heart has decreased vascular density and coronary vessel diameter and it requires sufficient diastolic aortic pressure for the left ventricle perfusion. Atrial muscle and the right ventricle are perfused during the entire heart cycle. The systolic pressure in the left ventricle forces blood vessels in the muscle wall to collapse, particularly in the subendocardial muscle layer. This makes the most active part of the heart prone to hypoxia. Optimal perfusion of the left ventricle wall requires sufficient aortic pressure during diastole, making individuals with higher diastolic pressures advantageous, in situations requiring combination of increased heart rate and output. Described mechanisms might have contributed to the hereditary quality of age-related hypertension in humans.
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Pp. 159 - 165
Renata Zadrag, Grzegorz Bartosz and Tomasz Bilinski
[Open Access Plus] |
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The applicability of the free radical theory of aging to the yeast S. cerevisiae is a matter of debate. In order to get an insight into this question, we studied the reproductive potential (the number of buds produced), reproductive lifespan (the time during which a yeast cell is able to divide), postreproductive lifespan (duration of life of yeast cells which ceased to divide) and total lifespan (sum of reproductive lifespan and postreproductive lifespan) of three isogenic pairs of yeast strains. Each pair contained a parent strain and a disruptant of gene(s) coding for important antioxidant enzyme( s) (CuZn-superoxide dismutase, all five peroxiredoxins or glutaredoxin 5). Although the reproductive potential was decreased in all antioxidant enzyme-deficient mutants, the differences in the reproductive lifespan between the parent strains and the mutants were less pronounced while postreproductive lifespan and total lifespan were not diminished in the mutants. These results suggest that either the free-radical theory of aging is not applicable to S. cerevisiae or that this yeast is not a proper model organism for the study of aging of higher organisms. In our opinion the latter possibility is more apparent and the increase in cell volume (unavoidable for a cell propagating by budding) rather than accumulation of oxidative damage may be the main reason for the cessation of budding (and perhaps postreproductive death) in S. cerevisiae.
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