Search

Epigenetics is revealing how "nature is nurtured", with environmental factors such as nutrition, environmental neurotoxicants, and psychological stress influencing DNA expression. In this current opinion paper, we argue that understanding the dynamic interplay between the genome acquired at conception and environmental exposures throughout life requires pregnancy and birth cohorts, and that greater Canadian national commitment to the infrastructure needed for sustaining such cohorts is warranted. We present a framework that is now being implemented in Alberta.

Although changes in the soleus H-reflex (an electrical analog of the tendon jerk) with age have been examined in a number of studies, some controversy remains. Also, the effect of age on inhibitory reflexes has received little attention. The purpose of this paper was to examine some excitatory and inhibitory reflexes systematically in healthy human subjects having a wide range of ages. We confirmed that both the maximum H-reflex (Hmax) and the maximum M-wave (Mmax) (from direct stimulation of motor axons) decrease gradually with age. The decrease in Hmax was larger so the Hmax/Mmax ratio decreased dramatically with age. Interestingly, the modulation of the H-reflex during walking was essentially the same at all ages, suggesting that the pathways that modulate the H-reflex amplitude during walking are relatively well preserved during the aging process. We showed for the first time that the short-latency, reciprocal inhibitory pathways from the common peroneal nerve to soleus muscle and from the tibial nerve to the tibialis anterior muscle also decreased with age, when measured as a depression of ongoing voluntary activity. These results suggest that there may be a general decrease in excitability of spinal pathways with age. Thus, the use of age-matched controls is particularly important in assessing abnormalities resulting from disorders that occur primarily in the elderly.

Skeletal muscle is highly vascularized, with perfusion being tightly regulated to meet wide-ranging metabolic demands. For decades, the capillary supply has been explored mainly in terms of evaluating the capillary numbers and their function in the supply of oxygen and substrates and the removal of metabolic byproducts. This review will focus on recent discoveries concerning the role played by capillaries in facilitating other aspects of cell regulation and maintenance, in health and disease, as well as alterations during the aging process. [ABSTRACT FROM AUTHOR]

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Applied Physiology, Nutrition & Metabolism is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)