Physical activity effects on bone metabolism

The incidence of osteoporotic fractures rises exponentially with age and is increasing faster than the demographic increase in the aging population. Physical activity has great potential to reduce the risk for osteoporotic fractures. Three independent but interactive factors contribute to the risk of fractures: bone strength, the risk of falling, and the effectiveness of neuromuscular response that protects the skeleton from injury. Exercise can reduce fracture risk not only by preventing bone loss, but by decreasing the risk of falling and the force of impact by improving strength, flexibility, balance, and reaction time. Extreme inactivity causes rapid bone loss of up to 40%, while athletic activity results in bone hypertrophy of up to 40%. Exercise intervention programs have reduced bone loss or increased bone mass in both men and women of various ages and initial bone status. These benefits have been shown for arm bone mineral content, total body calcium, spine, calcium bone index, tibia, and calcaneus. In both middle-aged and elderly women, physical activity intervention reduced bone loss or increased bone mass. The mechanisms for maintenance of skeletal integrity rely on a cellular response to hormonal and mechanical load stimuli. Studies in animal models show that training affects cellular activity. In osteoporotics, cellular erosion is increased and mineral apposition rate (MAR) decreased compared with normal age-matched controls. In contrast to this, sows trained on a treadmill 20 min per day for 20 weeks had greater active periosteal surface, periosteal MAR, and osteonal MAR than untrained sows.     

衰老对大鼠阴茎组织NO-cGMP通路及端粒酶活性的影响研究

目的探讨衰老对大鼠阴茎组织结构、NO(nitric oxide)-cGMP(cvclic Guanosine Monophosphate)通路及端粒酶活性的影响作用。方法本课题以不同月龄大鼠阴茎组织及培养的平滑肌细胞为研究对象,检测不同月龄大鼠阴茎组织中NO量、NOS(Nitric Oxide Synthase)活性、cGMP量、端粒酶活性及海绵体结构的变化,并比较大鼠、人阴茎组织及大鼠原代海绵体平滑肌细胞的端粒酶活性。结果(1)大鼠阴茎组织中NO量、NOS活性均先升高后降低,各月龄组间有显著差异。阴茎组织cGMP含量逐渐降低,各月龄组间差别显著；(2)随龄增加,平滑肌纤维逐渐减少,胶原纤维增多,粗大成团,窦状隙变少、变窄：(3)大鼠阴茎组织端粒酶活性以2月龄活性最高,随龄增加逐渐下降。人阴茎组织中无端粒酶活性。结论(1)衰老对大鼠阴茎组织结构、NO．cGMP通路及端粒酶活性有显著影响,提示衰老与ED关系密切；(2)大鼠阴茎组织有端粒酶活性,可作为研究细胞衰老与ED关系有关端粒酶的模型。     

Long-term effects of ovariectomy and aging on the rat skeleton

Summary The long-term skeletal effects of ovariectomy and aging were studied in female Sprague-Dawley rats sacrificed at 270, 370, and 540 days after bilateral ovariectomy (OVX) or sham surgery at 90 days of age. The proximal tibia was processed undecalcified for quantitative bone histomorphometry. For continuity, data from these late time points were combined with previously published data from earlier time points (0–180 days). A biphasic pattern of cancellous bone loss was detected in the proximal tibial metaphysis of OVX rats. An initial, rapid phase of bone loss out to 100 days was followed by an intermediate period of relative stabilization of cancellous bone volume at the markedly osteopenic level of 5–7%. After 270 days, a slow phase of bone loss occurred during which cancellous bone volume declined to 1–2%. Both the initial, rapid phase and the late, slow phase of bone loss in OVX rats were associated with increased bone turnover. In control rats, cancellous bone volume remained constant at 25–30% out to 270 days (12 months of age), then decreased to ∼10% by 540 days (21 months of age). This age-related bone loss was also associated with increased bone turnover. It is interesting to note that the proximal tibial growth plates were closed in approximately a quarter of the control rats by 15–21 months of age. Our data indicate that a slow rate of bone loss and increased bone turnover persist in OVX rats during the later stages of estrogen deficiency. Therefore, the development of osteopenia is coincident with increased bone turnover in OVX rats as well as in aged, control rats.     

Cellular immune response of bladder tumor patients: effects of aging on cytotoxic activity against T24

The cytotoxic activity of peripheral blood lymphocytes of 39 control subjects, 42 bladder tumor patients and 15 patients with urological cancer other than bladder tumor against human bladder tumor cultured cell T24 was tested by a 51Cr-release assay. In the healthy donor group, high cytotoxic activity was found in younger people and negative correlation was significantly found between the cytotoxicity and age. On the other hand, high cytotoxic activity was frequently found in older patients with bladder tumors and no correlation between the cytotoxicity and age was found in this group. The mean % cytotoxicity for patients over 50 years old in the bladder tumor group was significantly higher than that for the healthy donor group and other carcinoma group. A large proportion of the cytotoxicity of the control subjects and the bladder tumor patients to T24 was due to lymphocytes that did not form spontaneous rosettes with sheep erythrocytes.     

The effects of morphology and histopathologic findings on the mobility of the sacroiliac joint

The sacroiliac joints of seven pelvic specimens were examined to determine functional, morphologic, and histopathologic aspects. The movements were measured in four intact pelvises (from two men and two women). The joint surfaces of all pelvises (from three men and four women) then were examined topographically by means of a photogrammetric method. After this, they were examined histologically to characterize any effects on function. The morphologic investigation revealed sex-specific differences. All joint surfaces from the female pelvises showed circular contours, the centers of which coincided with the iliac tuberosities. These morphologic characteristics were not discernible in the joint surfaces from the male pelvises; these had interlocking irregularities without a topographic pattern. As expected, this configuration involved distinct differences in mobility. Rotation of the sacrum was markedly less in the sacroiliac joints of men than in those of women.     

The effects of normal aging on the response of the pituitary-gonadal axis to chronic clomiphene administration in men

Serum androgens decline with age in normal men, despite normal or elevated bioactive serum gonadotropins, suggesting that primary testicular dysfunction occurs with aging. The authors further assessed the question of age-related testicular dysfunction by evaluating whether raising serum gonadotropins above the normal serum range for an extended time in healthy elderly men might result in bringing their gonadal function to a level similar to that found in young adult men. Five elderly (65 to 85 years old) and five young adult men (26 to 33 years old) were given 50 mg of clomiphene citrate (CC) twice a day for 8 weeks to stimulate gonadotropin production. During that time, testosterone (T), non-sex hormone-binding globulin bound T, and estradiol increased significantly in both age groups, while serum inhibin increased significantly only in the young adult men. The increases in serum androgens with CC administration were significantly greater in the young adult men than in the elderly men. These hormone changes occurred in the setting of serum gonadotropins that increased significantly in both age groups, although there was a tendency for the elderly men to have a smaller increase in luteinizing hormone. Despite 8 weeks of stimulation of the pituitary-gonadal axis by CC administration, the elderly men demonstrated significantly diminished testicular responses compared with the young adult men. Sertoli cell function, as determined by inhibin production, was more diminished in the elderly men than was Leydig cell function. These data strengthen the hypothesis that normal aging in men is accompanied by a decline in testicular function.     

Long-term effects of exercise on the range of motion of aging women

Loss of mobility is important to everyone, particularly the elderly. The purpose of this retrospective, longitudinal study was to determine the long-term (5-year) effects of exercise on the shoulder and hip range of motion of a group of 12 women aged 50-71 years. Shoulder flexion, shoulder extension, shoulder transverse extension, hip flexion, and hip rotation were measured a minimum of five times throughout the 5-year period. A flexometer was used to measure range of motion. The results of the study indicated that range of motion increased significantly (p < 0.05) throughout the study in four of the five measurements. The fifth measurement (shoulder flexion) also improved but not significantly. These data indicate that aging women can improve and/or maintain shoulder and hip range of motion through participation in regular exercise done thee times per week for 5 years. J Orthop Sports Phys Ther 1992;16(1):37-42.     

Physical activity in the treatment of fibromyalgia

International treatment recommendations for fibromyalgia (FM) highlight the importance of adapted physical activity (APA) combined with patient education. Cognitive and behavioral therapies as well as an interdisciplinary approach can be proposed for more complex or severe clinical situations, with a biopsychosocial vision of rehabilitation. To personalize the rehabilitation's therapeutic approach, a clinician can use simple and validated instruments for measuring physical performance that will highlight levels of physical conditioning, which range from low to very low in FM patients. Several systematic reviews and meta-analyses have found strong evidence that supervised aerobic and resistance-training programs reduce the pain intensity and significantly improve the quality of life and the physical and psychological functioning of female FM subjects. These therapeutic approaches appear safe and promising in terms of cost-effectiveness and should be the subject of more randomized controlled trials among male FM subjects and adolescents.     

黄芪延缓小鼠皮肤衰老的实验研究

目的：从形态学角度研究黄芪延缓小鼠皮肤衰老的作用。方法：小鼠随机分成3组,空白组（C）灌胃生理盐水20ml/kg,黄芪低剂量组（L）和黄芪高剂量组（H）分别灌胃黄芪提取液4g/kg、16g/kg,每次20ml/kg。30天后做组织学切片检测。结果：与C组比较,L组和H组皮肤组织中真皮厚度和胶原纤维面积增加（P〈0.01）。H组与L组比较,真皮厚度和胶原纤维面积显著增加（P〈0.05）。结论：高剂量黄芪可使真皮厚度和胶原纤维面积明显增加,具有延缓小鼠皮肤衰老的作用。     

The effects of aging on the neural correlates of subjective and objective recollection

High-functioning older adults can exhibit normal recollection when measured subjectively, via "remember" judgments, but not when measured objectively, via source judgments, whereas low-functioning older adults exhibit impairments for both measures. A potential explanation for this is that typical subjective and objective tests of recollection necessitate different processing demands, supported by distinct brain regions, and that deficits in these tests are observed according to the degree of age-related changes in these regions. Here, we used event-related functional magnetic resonance imaging to measure the effects of aging on neural correlates of subjective and objective measures of recollection, in young, high-functioning (Old-High) and low-functioning (Old-Low) older adults. Behaviorally, the Old-High group showed intact subjective ("remember" judgments) but impaired objective recollection (for 1 of 2 spatial or temporal sources), whereas the Old-Low group was impaired on both measures. Imaging data showed changes in parietal subjective recollection effects in the Old-Low group and in lateral frontal objective recollection effects in both older adult groups. Our results highlight the importance of examining performance variability in older adults and suggest that differential effects of aging on brain regions are associated with different patterns of performance on tests of subjective and objective recollection.     

Selective delay activity in the cortex: phenomena and interpretation

The present article does not intend to present technical progress nor recent successes in accounting for experiments, as this issue of the journal presents a rich inventory. Rather, the paper presents a retrospective reflection on the history of the subject; on the relation between the different aspects of the concepts and the phenomena involved; on its strengths and weaknesses; and on some future prospects. It is a tribute to an extremely rich and growing wealth of physiological phenomena and of interpretative concepts. Yet the extent of achievement is used to expose open questions, which appear to become ever deeper. It is also an attempt to make the subject a matter of discourse between biologists and modelers, without the distraction of technical details.     

Effects of aging on mitochondrial enzyme activity of rat urinary bladder

OBJECTIVES: Our previous study showed that aged rat bladders became fatigued faster than young bladders following repeated contraction induced by electrostimulation. One factor might be a lower energy-producing capability secondary to a decreased mitochondrial enzyme activity of the aged bladder. This study examined this possibility. MATERIALS AND METHODS: Mitochondria from 3- (n = 11) and 24-month-old (n = 10) Sprague-Dawley rats were isolated. Activities of the following enzymes were assayed: two key enzymes in the citric acid cycle, citrate synthase and malate dehydrogenase, and three enzymes in the respiratory chain reaction, NADH-cytochrome c reductase, succinate-cytochrome c reductase and cytochrome c oxidase. The concentration of phosphocreatine and ATP in the aged rat bladders and a separate group of young bladders (n = 12) was determined using high-performance liquid chromatography. RESULTS: (1) The aged bladders have a significantly lower level of phosphocreatine and ATP content than those of young bladders. (2) The activities of all five enzymes assayed were significantly lower in the aged bladders than in young bladders, especially for citrate synthase, which had only 46.8% of the activity of young bladders. CONCLUSIONS: Aging reduces the mitochondrial enzyme activity of the rat bladder resulting in a lower energy-production capability, which might explain some of the voiding dysfunctions found in the elderly.     

Physical activity and the strength of the lumbar spine

The cadaveric lumbar spines of nine young men killed in road accidents were subjected to a range of mechanical tests, and the results compared with the men's occupational and recreational histories. It was found that the compressive strength of the spines tended to increase with the level of physical activity in life, but the increase was significant only in the eight spines aged 18 or over. Compressive failure usually occurred in the vertebral body, but in three cases, the disc prolapsed into the vertebral canal; these discs came from three of the four most physically active individuals. It is concluded that physical activity strengthens both the vertebrae and the discs. A high level of activity can cause vertebral strength to exceed that of the discs.     

超声波技术治疗皮肤老化临床效果的初步观察

目的观察超声波技术治疗颜面部皮肤老化的临床疗效。方法采用超声波治疗仪的特定声波强度,对60例颜面部皮肤老化者进行治疗。颜面部皮肤老化的治疗10次为一个疗程,每隔一天治疗一次,观察临床效果。针对每例患者治疗前后的对比照片,并做好记录,进行临床疗效的评估。结果本组患者60例,其中额部皱纹:显效12例,有效36例,无效12例;鱼尾纹:显效15例,有效36例,无效9例;眉间皱纹:显效6例,有效42例,无效12例。无一例出现面部红斑及损伤等不良反应。结论使用超声波皮肤治疗仪能改善面部皮肤松弛与老化,操作简单,安全可靠,患者无痛苦,易于接受,是目前具有临床推广价值的方法。     

面部埋线对女性老化皮肤的作用效应

目的 观察面部埋线疗法对女性老化皮肤的作用效应.方法 选取60例面部皮肤老化的女性志愿者,随机分为埋线组和假埋线对照组,每组各30例.埋线组接受埋线治疗;对照组同样接受埋线针刺入,但不注线.各组均操作2次,21d1次,共计42 d.分别于治疗前后用VISIA皮肤图像分析仪和CK皮肤性质检测仪对志愿者面部皮肤进行定量分析和评价.结果 埋线组面部皮肤皱纹、纹理、毛孔、水分、弹性改善明显（P＜0.05）,紫外线色斑、红血丝、色素变化不明显（P＞0.05）.对照组皮肤无明显变化（P＞0.05）.结论 面部埋线疗法可一定程度地改善女性面部皮肤老化,无明显不良反应,可以作为改善面部皮肤老化的方法之一.     

Model of global spontaneous activity and local structured activity during delay periods in the cerebral cortex

We investigate self-sustaining stable states (attractors) in networks of integrate-and-fire neurons. First, we study the stability of spontaneous activity in an unstructured network. It is shown that the stochastic background activity, of 1-5 spikes/s, is unstable if all neurons are excitatory. On the other hand, spontaneous activity becomes self-stabilizing in presence of local inhibition, given reasonable values of the parameters of the network. Second, in a network sustaining physiological spontaneous rates, we study the effect of learning in a local module, expressed in synaptic modifications in specific populations of synapses. We find that if the average synaptic potentiation (LTP) is too low, no stimulus specific activity manifests itself in the delay period. Instead, following the presentation and removal of any stimulus there is, in the local module, a delay activity in which all neurons selective (responding visually) to any of the stimuli presented for learning have rates which gradually increase with the amplitude of synaptic potentiation. When the average LTP increases beyond a critical value, specific local attractors (stable states) appear abruptly against the background of the global uniform spontaneous attractor. In this case the local module has two available types of collective delay activity: if the stimulus is unfamiliar, the activity is spontaneous; if it is similar to a learned stimulus, delay activity is selective. These new attractors reflect the synaptic structure developed during learning. In each of them a small population of neurons have elevated rates, which depend on the strength of LTP. The remaining neurons of the module have their activity at spontaneous rates. The predictions made in this paper could be checked by single unit recordings in delayed response experiments.      

超声波技术治疗皮肤老化临床效果的初步观察

目的观察超声波技术治疗颜面部皮肤老化的临床疗效。方法采用超声波治疗仪的特定声波强度，对60例颜面部皮肤老化者进行治疗。颜面部皮肤老化的治疗10次为一个疗程，每隔一天治疗一次，观察临床效果。针对每例患者治疗前后的对比照片，并做好记录，进行临床疗效的评估。结果本组患者60例，其中额部皱纹：显效12例，有效36例，无效12例；鱼尾纹：显效15例，有效36例，无效9例；眉间皱纹：显效6例，有效42例，无效12例。无一例出现面部红斑及损伤等不良反应。结论使用超声波皮肤治疗仪能改善面部皮肤松弛与老化，操作简单，安全可靠，患者无痛苦，易于接受，是目前具有临床推广价值的方法。