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1.  Effects of dietary restriction and exercise on the age-related pathology of the rat 
Age  1997;20(2):107-118.
Intervention of the aging process is an effective, experimental means of uncovering the bases of aging. The most efficacious and commonly used intervention used to retard the aging processes is dietary restriction (DR). It increases mean and maximum life spans, delays the appearance, frequency, and severity of many age-related diseases, and more importantly, attenuates much of the physiological decline associated with age. Although the subject of intense research, the mechanism by which DR alters the aging processes is still unknown. Physical exercise is another effective intervention shown to affect aging phenomena, especially when applied in combination with DR. Mild exercise in concert with DR is beneficial, but vigorous exercise coupled with DR could be deleterious. With regard to pathology, exercise generally exerts a salutary influence on age-related diseases, both neoplastic and non-neoplastic, and this effect may contribute to the increase in median life span seen with exercised rats. Exercise coupled with 40% DR was found to suppress the incidence of fatal neoplastic disease compared to the sedentary DR group. Exercise with mild DR suppressed the incidence of multiple fatal disease and chronic nephropathy, and also delayed the occurrence of many age-related lesions compared to the ad libitum (AL) control group. However, these effects may have little bearing on the aging process per se, as maximum life span is only minimally affected. Although not as intensively studied as DR, results from studies that utilize exercise as a research probe, either alone or in combination with DR, have helped to assess the validity of proposed mechanisms for DR and aging itself. Neither the retardation of growth rate nor the increase in physical activity, observed with either exercise or DR, appear to contribute to the anti-aging action of DR. Moreover, results from lifelong exercise studies indicate that the effects of DR do not depend upon changes in energy availability or metabolic rate. The mechanisms involving effects on adiposity or immune function are also inadequate explanations for the action of DR on aging. Of the proposed mechanisms, only one, as postulated by the Oxidative Stress Hypothesis of Aging, tenably accounts for the known effects of DR and exercise on aging.
doi:10.1007/s11357-997-0010-4
PMCID: PMC3456154  PMID: 23604296
Calories; Food intake; Physical activity; Longevity; Life span; Aging; Disease
2.  Force-Generating Capacity and Contractile Protein Content of Arterial Smooth Muscle 
The Journal of General Physiology  1974;64(6):691-705.
After correction for extracellular space (40%) determined from electron micrographs, the maximum isometric force developed by strips prepared from the media of the hog carotid artery (2.2 x 106 dyn/cm2) can be extrapolated to give a value of 3.7 x 106 dyn/cm2 for the smooth muscle component of the strip. Three independent estimates of the myosin content of the smooth muscle cells were made based on (a) exhaustive extraction and purification with estimates of preparative losses, (b) the myosin catalyzed ATPase activity of media homogenates, and (c) quantitative densitometry of the peaks containing myosin, actin, and tropomyosin after disk electrophoresis of sodium dodecyl sulfate-treated media homogenates. The results were consistent and gave a myosin content of 5–10 mg/g media, or 8–17 mg/g cell. Method (c) gave myosin:actin:tropomyosin weight ratios of 1:3.2:0.8. Although measured force developed by the smooth muscle cell exceeds that of mammalian striated muscle, the myosin content in smooth muscle is about five times lower. The actin content of smooth muscle is relatively high. The actin and myosin contents are consistent with thick and thin filament ratios observed in electron micrographs of vascular smooth muscle.
PMCID: PMC2226183  PMID: 4280433

Results 1-2 (2)