The heat shock/oxidative stress connection

Involvement of free-radical oxidations in the aging process has been a topic of interest since Harman's original contribution. Because of the close association between aging and Alzheimer disease (AD) and the qualitative similarity in the neuropathology of both conditions, it has been proposed by many investigators that oxidative stress may be important in AD. If such modality of injury was indeed involved, one should expect to find markers of oxidation and heat shock (since free radicals are key mediators of heat-shock induction) in brains of patients with AD. In fact, several studies documented abnormal expression of antioxidant enzymes and heat-shock proteins (HSP) along with other markers of oxidation in AD brains. We showed that abnormally expressed antioxidant enzymes are topographically associated with senile plaques and neurofibrillary tangles, and that the activity of these enzymes is (contrary to what one would expect) markedly reduced. These findings have recently been confirmed by other investigators. Despite a large amount of evidence that suggests an association between oxidative stress and the pathogenesis of AD, it is not yet known whether oxidative stress is a cause or consequence of the disorder. Future research efforts regarding the oxidative stress hypothesis of AD should include attempts, at generating AD pathology by oxidative means in laboratory animals, determining the role and integrity of the heat-shock response in AD, as well as that of various antioxidant systems, growth factors, and hormones with antioxidant and neuroprotective properties.     

老年大鼠脑M_1亚型受体的变化及黄芪的调节作用

目的：观察老年大鼠不同脑区胆碱能Ｍ１亚型受体的变化和黄芪对其的调节作用。方法：采用放射自显影技术显示大鼠脑Ｍ１受体，并用图像分析仪进行灰度分析，以反映Ｍ１受体在不同脑区的相对定量分布。结果：所得脑切片自显影灰度层次清晰，主要分布在大脑皮质、海马、纹状体部位，非特异结合灰度很低，老年大鼠皮质、海马、纹状体的灰度显著低于青年鼠，分别降低１５７８％，８６９％，１２３６％（Ｐ＜００５），老年服黄芪组三个部位的灰度均明显高于老年对照组，分别升高１６６３％，９８１％，１０３２％，（Ｐ＜００５）。结论：黄芪对老年大鼠降低的脑胆碱能Ｍ１亚型受体具有上调作用。     

Metabolite changes with age measured by proton magnetic resonance spectroscopy in normal subjects

Abstract  To determine whether there are metabolite changes in the left medial temporal and frontal lobes with aging, we performed proton magnetic resonance spectroscopy in 36 normal subjects. The N-acetylaspartate/creatine-phosphocreatine ratio in the medial temporal lobe tended to be decreased in subjects over 60 years of age. The ratio decrease in the frontal lobe related to aging was lower than that in the medial temporal lobe. There were no significant differences in the metabolite ratios between males and females. These findings suggest that structures in the medial temporal lobe may be more susceptible to neuronal dysfunction associated with aging than those in the frontal lobe.     

The Effect of Aging on Erectile Function Induced by Apomorphine and Electric Field Stimulation to Rat

Population aging has become a world wide tendency and according to the UNproject,the proportion of population above60 years old would exceed the proportionof children below1 5years old by2 0 50 .Erectile dysfunction(ED) seriously affectsthe quality of lif…     

The aging brain

A recent interest in aging of the nervous system is related to the remarkable increase in the numbers of elderly persons throughout the world. As a reflection of the added years, pathologies in the older person have also increased. Primary among those which affect the activities and behavior of these people are the dementias, especially Alzheimer's Disease. To focus on such problems, however, requires an understanding of the changes which take place in the normal aging nervous system. This paper reviews some of the accepted criteria for these changes as well as the possible attempts by the nervous system to alter its structure in response to these changes.     

The effects of aging on the circadian rhythm of serum cortisol in the dog

The purpose of this study was to determine if aging affects the circadian rhythm of serum cortisol. Female beagle dogs belonging to three age groups were used: adult (3.3 ± 0.6 (SD) years), old (12.1 ± 0.3 years), and puppies (8.4 ± 0.2 weeks). Blood samples were collected by cephalic or jugular venipuncture at 3-h intervals during three 24-h periods and analyzed for total serum cortisol concentrations by radioimmunoassay. The circadian rhythm was present in the serum cortisol of adult animals, but no significant changes during a 24-h period could be detected in the old animals. No circadian rhythm in serum cortisol was present in the puppies. It is concluded that the circadian rhythm in plasma cortisol is disrupted in old animals and is not yet developed in puppies.     

Conditions of Alzheimer-type dementia in the old-old and oldest-old patients with special reference to extreme conditions of brain aging

A neuropathological study on 1540 consecutive autopsy brains ranging from 60 to 107 years of age revealed the following points. (1) Of the of the demented cases of the plaque-predominant type, 93% were complicated with multiple tiny cortical infarcts. They showed a tendency for dementia to develop before or after the appearance or worsening of a systemic disorder such as cardiovascular disease, respiratory infection and cancer. However, there was no case showing Alzheimer-type dementia (ATD). (2) The plaque-predominant type might be an extreme condition of brain aging in terms of senile plaques (SP). It is likely that although the pathological appearance of SP alone is not responsible for dementia, its coexistence with multiple cortical infarcts could be the cause of dementia. Therefore, this type should be distinguished from ATD. (3) Primary hippocampal degeneration could also be an extreme condition of brain aging in terms of neurofibrillary tangles. This condition was different pathologically from the hippocampal lesion in ATD. (4) Several characteristics of old-old and oldest-old patients were clarified.     

Density distribution of erythrocytes in class A2 (insulin requiring) gestational diabetes

We evaluated the age distribution of erythrocytes in pregnancy complicated by gestational diabetes class A2 by the density distribution of cells (DDC) method. The values for normal pregnancy and nonpregnant women were obtained from recently published studies. The cumulative density distribution of cells (DDC) of women with gestational diabetes resembled that of normal pregnancy.     

The influence of white matter lesions on neuropsychological functioning in demented and non-demented 85-year-olds

White matter lesions on computed tomography of the head were studied in relation to neuropsychological functioning in subjects from a representative sample of non-demented ( n = 134) and demented ( n = 98) 85-year-olds. Non-demented subjects with white matter lesions ( n = 46) scored significantly lower in tests of verbal ability (Synonyms), spatial ability (Block Design, Clock Test), perceptual speed (Identical forms), secondary memory (Thurstone Picture Memory), basic arithmetic (Coin Test) and the global cognitive screening test Mini-Mental State Examination than non-demented subjects without white matter lesions ( n = 88). Demented subjects with white matter lesions ( n = 67) scored significantly lower in tests of spatial ability (Block Design and Clock Test) and secondary memory (free recall in the MIR memory test, Ten-word memory test I and II) and in the Mini-Mental State Examination than demented subjects without white matter lesions ( n = 31). It is concluded that white matter lesions contribute to cognitive decline in both non-demented and demented elderly subjects.     

Self-efficacy and the maintenance of exercise participation in older adults

The role played by exercise self-efficacy in the maintenance of exercise participation of previously sedentary middle-aged adults 4 months after the termination of a formal exercise program is reported. Correlational and multiple regression analyses examined the influence of self-efficacy, physiological (aerobic capacity, sex, body composition), and behavioral (past exercise frequency and intensity) parameters in the maintenance of exercise participation. Self-efficacy significantly predicted exercise behavior at follow-up when controlling for biological and behavioral influences. Aerobic capacity, exercise efficacy, and exercise behavior in combination were significantly related to current energy expenditure in aerobic physical activity. The discussion focuses on the need to examine the impact of different correlates of exercise behavior at different stages of the exercise process.This project was funded by Grant AG07907 from the National Institute on Aging.