摘要:

The relationship between ageing and glucose homeostasis is still an open debate. In fact, the mechanisms by which glucose metabolism is progressively impaired with increasing age are not completely understood. In the present report we have reviewed the possible mechanisms (impaired insulin secretion and action, role of the environmental factors) which may lead to the impairment in glucose handling associated with ageing. We also point out that not all aged subjects are glucose intolerant; in fact, it has been suggested that only those aged subjects who present more than one pathological finding do in fact develop impaired glucose handling.

ISSN:1663-2818    

DOI:10.1159/000184237

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

From epidemiological and experimental evidence it has been concluded that ovarian steroids have a large variety of cardiovascular effects. Among these are a direct action on the vascular wall, alterations in hemodynamics, modification of protein metabolism involved in the arteriosclerosis process, and alterations in the risk of cardiovascular morbidity and mortality. Some of the earlier epidemiological studies indicated an increased risk of cardiovascular disease (CVD) in estrogen users, but later on the majority of the published studies reported consistently a striking decrease in CVD by about 50%. The consistency in the positive results observed in successive epidemiological reports from various countries strongly suggest a protective effect of hormone replacement therapy on CVD morbidity. However, the direct demonstration of a protective effect of estrogens on CVD morbidity and mortality can only be made by long-term prospective controlled studies.

ISSN:1663-2818    

DOI:10.1159/000184238

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Ageing is associated with the appearance of several serum autoantibodies, including thyroid autoantibodies. The biological and clinical significance of this phenomenon is still unknown, since, with the exception of primary myxedema, the prevalence of clinically overt thyroid autoimmune diseases is not increased in the elderly. The peculiar link between autoimmune thyroid failure and ageing is also underscored by the high prevalence of subclinical hypothyroidism in elderly subjects with positive serum thyroid autoantibodies, and could be the consequence of preferential age-dependent expression of destructive effector mechanisms and/or increased target gland susceptibility. Thyroid autoimmunity and subclinical hypothyroidism have also been implicated in the pathogenesis of other age-associated disorders, in particular coronary heart disease. Interestingly, recent data from our laboratories showed that thyroid autoantibodies are rare in healthy centenarians and in other highly selected aged populations, while they are frequently observed in unselected or hospitalized elderly. Taken together, these data suggest that thyroid autoimmune phenomena are not the consequence of the ageing process itself, but rather might be related to age-associated disease.

ISSN:1663-2818    

DOI:10.1159/000184239

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Bone remodeling tightly couples resorption and formation in a cell unit called bone modeling unit (BMU). The activity of the BMU leads to a negative balance of bone mass in adults with physiological osteopenia. The regulation of the BMU is done at a local level by paracrine and autocrine factors such as cytokines and at an endocrine level by hormones. The hormonal level has been widely discussed in previous reviews and recent studies focus on the relations between hormonal triggers and cytokine-mediated responses to their stimulations. This review is dedicated to the means of coupling osteoblasts and osteoclasts and the recruitment of early cell precursors that originate in the hematopoietic bone marrow. Bone should be considered not only as an individual organ but as integrated in the bone-bone marrow organ.

ISSN:1663-2818    

DOI:10.1159/000184240

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Calcium availability is reduced in the elderly because not only of decreased dietary intake of calcium and vitamin D, but also reduced solar exposure and a decrease in the production of provitamin D by the skin. Moreover, calcitriol synthesis and calcitriol activity on calcium absorption by the small intestine are decreased with ageing. The age-related plasma parathormone increase enhances bone remodelling. The decrease of calcitonin secretion in the elderly is possibly related to a loss of sex steroids and calcitriol. 24-hour integrated growth hormone (GH) and insulin-like growth factor I concentrations are also decreased with ageing, but the effectiveness of GH therapy on bone mass in the elderly is still assumed.

ISSN:1663-2818    

DOI:10.1159/000184241

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Several recent studies show that bone loss continues in the elderly, and that various regimens are still effective in the elderly to stop bone loss. Thus, diagnostic procedures for osteoporosis should be considered in elderly women, i.e. measurement of bone mass by dual energy X-ray absorptiometry of the hip, spine or forearm that have been shown to predict the subsequent risk of fractures. The rate of bone turnover, and therefore of bone loss, is quite variable from patient to patient and can be assessed with improved sensitivity and specificity with the new markers that are specific for bone formation and bone resorption.

ISSN:1663-2818    

DOI:10.1159/000184242

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Several approaches may be suggested for prevention or treatment of senile osteoporosis. In elderly patients, an association of calcium and vitamin D supplementation has been shown to reduce nonvertebral fractures up to 40% over an 18-month period. Calcitonin, given parenterally or nasally, may prevent further bone loss and has been reported to significantly decrease vertebral and hip fractures. This hormone also possesses an important analgesic effect. Fluoride salts are the most effective way to significantly increase bone mass, mainly at the trabecular site. The optimal doses and regimens remain to be clearly established. The use of new formulations like sodium monofluorophosphate are likely to facilitate the search of the optimal therapeutic window. Bisphosphonates are potent inhibitors of bone resorption. They have been shown to significantly increase trabecular bone mass without impairment of cortical bone. Their use may be associated with a significant decrease in vertebral fractures, mainly in patients with severe osteoporosis. The new, second and third generation of bisphosphonates (tiludronate, risedronate, alendronate) look extremely promising but their widespread use will only be possible after a confirmation of the absence of a deleterious effect on bone quality (alendronate) and after demonstration of a reduction in vertebral and/or hip fractures following a prolonged use.

ISSN:1663-2818    

DOI:10.1159/000184243

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

The observation that topical retinoic acid could attenuate wrinkles and other features of skin photoageing has projected this molecule into the media spotlight. Behind this effect are in fact major basic biological issues related to the role of retinoids in tissue maintenance and their possible interference with the molecular biology of cellular ageing.

ISSN:1663-2818    

DOI:10.1159/000184244

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Growth hormone deficiency (GHD) in adults is now recognized as a specific clinical syndrome with characteristic symptoms and signs. Thus, the patients are overweight, have an abnormal body composition (excess body fat and a decrease in the extracellular water volume) and a low bone mineral content compared to normals. Furthermore, the GHD patients have lipid abnormalities, decreased insulin sensitivity and a decreased fibrinolysis. Finally, the ‘quality of life’ is low in terms of energy and social life. Short- and long-term studies with recombinant human GH (rhGH) treatment have shown normalization of body composition, increase in the lipid pattern and marked improvement of the psychological well-being. The treatment seems safe with no serious side effects reported. In analogy with other hormonal replacement therapies, the rhGH dose should be individuali

ISSN:1663-2818    

DOI:10.1159/000184245

出版商:S. Karger AG    

年代:1995

数据来源: Karger

摘要:

Postmenopausal women are 2-3 times more likely to have a heart attack than premenopausal women. According to the results of the Framingham study, angina is one of the main manifestations of coronary heart disease in women, whereas myocardial infarction and sudden death are more frequent in men. Cigarette smoking, high blood pressure and hypercholesterolemia are major risk factors for coronary heart disease in both men and women, while diabetes mellitus and hypo-high-density lipoproteinemia are more clearly associated with cardiovascular disease in women than in men. Endogenous and exogenous hormones may be a major determinant of the cardiovascular risk in women. Premenopausal women have a considerably lower incidence of coronary heart disease than postmenopausal women, and estrogen therapy is associated with a reduced risk in the latter. Part of this protective effect seems to be due to the influence of estrogen therapy on lipoprotein metabolism, i.e. a decrease in LDL cholesterol and an increase in HDL cholesterol. Progestins, to an extent which depends on their androgenic potency, have the opposite effects. A large study (the Postmenpausal Estrogen Progestin Intervention Trial) has been launched to test the effect of the estrogen-progestin combination on various cardiovascular risk factors.

ISSN:1663-2818    

DOI:10.1159/000184246

出版商:S. Karger AG    

年代:1995

数据来源: Karger