OBJECTIVES: We determined whether caloric restriction(CR) has cardiac specific effects that attenuate the established aging-associated impairments in diastolic function(DF). BACKGROUND: Caloric restriction retards t...OBJECTIVES: We determined whether caloric restriction(CR) has cardiac specific effects that attenuate the established aging-associated impairments in diastolic function(DF). BACKGROUND: Caloric restriction retards the aging process in small mammals; however, no information is available on the effects of long-term CR on human aging. In healthy individuals, Doppler echocardiography has established the pattern of aging-associated DF impairment, whereas little change is observed in systolic function(SF). METHODS: Diastolic function was assessed in 25 subjects(age 53± 12 years) practicing CR for 6.5± 4.6 years and 25 age- and gender-matched control subjects consuming Western diets. Diastolic function was quantified by transmitral flow, Doppler tissue imaging, and model-based image processing(MBIP) of E waves. C-reactive protein(CRP), tumor necrosis factor-alpha(TNF-α ), and transforming growth factor-beta1(TGF-β 1) were also measured. RESULTS: No difference in SF was observed between groups; however, standard transmitral Doppler flow DF indexes of the CR group were similar to those of younger individuals, and MBIP-based, flow-derived DF indexes, reflecting chamber viscoelasticity and stiffness, were significantly lower than in control subjects. Blood pressure, serum CRP, TNF-α , and TGF β 1 levels were significantly lower in the CR group(102± 10/61± 7 mm Hg, 0.3± 0.3 mg/l, 0.8± 0.5 pg/ml, 29.4± 6.9 ng/ml, respectively) compared with the Western diet group(131± 11/83± 6 mm Hg, 1.9± 2.8 mg/l, 1.5± 1.0 pg/ml, 35.4± 7.1 ng/ml, respectively). CONCLUSIONS: Caloric restriction has cardiac- specific effects that ameliorate aging-associated changes in DF. These beneficial effects on cardiac function might be mediated by the effect of CR on blood pressure, systemic inflammation, and myocardial fibrosis.展开更多
Thermal losses for a buried vertical thin plate can be expressed as a function of the assigned temperature distribution,the medium conductivity and the geometrical properties that describe the model. When the geometri...Thermal losses for a buried vertical thin plate can be expressed as a function of the assigned temperature distribution,the medium conductivity and the geometrical properties that describe the model. When the geometricalproperties reduce to one, the plate-ground thermal resistance can be expressed regardless of plate dimension, dependingonly on temperature distribution given at surface plate and its temperature difference with medium.展开更多
文摘OBJECTIVES: We determined whether caloric restriction(CR) has cardiac specific effects that attenuate the established aging-associated impairments in diastolic function(DF). BACKGROUND: Caloric restriction retards the aging process in small mammals; however, no information is available on the effects of long-term CR on human aging. In healthy individuals, Doppler echocardiography has established the pattern of aging-associated DF impairment, whereas little change is observed in systolic function(SF). METHODS: Diastolic function was assessed in 25 subjects(age 53± 12 years) practicing CR for 6.5± 4.6 years and 25 age- and gender-matched control subjects consuming Western diets. Diastolic function was quantified by transmitral flow, Doppler tissue imaging, and model-based image processing(MBIP) of E waves. C-reactive protein(CRP), tumor necrosis factor-alpha(TNF-α ), and transforming growth factor-beta1(TGF-β 1) were also measured. RESULTS: No difference in SF was observed between groups; however, standard transmitral Doppler flow DF indexes of the CR group were similar to those of younger individuals, and MBIP-based, flow-derived DF indexes, reflecting chamber viscoelasticity and stiffness, were significantly lower than in control subjects. Blood pressure, serum CRP, TNF-α , and TGF β 1 levels were significantly lower in the CR group(102± 10/61± 7 mm Hg, 0.3± 0.3 mg/l, 0.8± 0.5 pg/ml, 29.4± 6.9 ng/ml, respectively) compared with the Western diet group(131± 11/83± 6 mm Hg, 1.9± 2.8 mg/l, 1.5± 1.0 pg/ml, 35.4± 7.1 ng/ml, respectively). CONCLUSIONS: Caloric restriction has cardiac- specific effects that ameliorate aging-associated changes in DF. These beneficial effects on cardiac function might be mediated by the effect of CR on blood pressure, systemic inflammation, and myocardial fibrosis.
文摘Thermal losses for a buried vertical thin plate can be expressed as a function of the assigned temperature distribution,the medium conductivity and the geometrical properties that describe the model. When the geometricalproperties reduce to one, the plate-ground thermal resistance can be expressed regardless of plate dimension, dependingonly on temperature distribution given at surface plate and its temperature difference with medium.
