Profile of neurohumoral agents on mesenteric and intestinal blood flow in health and disease.
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The mesenteric and intestinal blood flow is organized and regulated to support normal intestinal function, and the regulation of blood flow is, in part, determined by intestinal function itself. In the process of the development and adaptation of the intestinal mucosa for the support of the digestive processes and host defense mechanisms, and the muscle layers for propulsion of foodstuffs, a specialized microvascular architecture has evolved in each tissue layer. Compromised mesenteric and intestinal blood flow, which can be common in the elderly, may lead to devastating clinical consequences. This problem, which can be caused by vasospasm at the microvascular level, can cause intestinal ischaemia to any of the layers of the intestinal wall, and can initiate pathological events which promote significant clinical consequences such as diarrhea, abdominal angina and intestinal infarction. The objective of this review is to provide the reader with some general concepts of the mechanisms by which neurohumoral vasoactive substances influence mesenteric and intestinal arterial blood flow in health and disease with focus on transmural transport processes (absorption and secretion). The complex regulatory mechanisms of extrinsic (sympathetic-parasympathetic and endocrine) and intrinsic (enteric nervous system and humoral endocrine) components are presented. More extensive reviews of platelet function, atherosclerosis, hypertension, diabetes mellitus, the carcinoid syndrome, 5-hydroxytryptamine and nitric oxide regulation of vascular tone are presented in this context. The possible options of pharmacological intervention (e.g. vasodilator agonists and vasoconstrictor antagonists) used for the treatment of abnormal mesenteric and intestinal vascular states are also discussed. (+info)
Survival of healthy older people.
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The purpose of this study was to discover any relationships which might exist between measurable variables recorded when a healthy group of men and women, aged 70 years and over, were examined and their subsequent survival time. It was found that height, body weight, systolic and diastolic blood pressures, haemoglobin, hand grip power, cardiothoracic ratio, and pulse rate are of no predictive value in the estimation of survival time. Survival is not influenced by marital status or occupational class. For both sexes the degree of kyphosis and age are useful predictive criteria in respect of survival time. However, much research work requires to be done to explain why many people die at the time they do. (+info)
Does justice require genetic enhancements?
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It is argued that justice in some cases provides a pro tanto reason genetically to enhance victims of the genetic lottery. Various arguments--both to the effect that justice provides no such reason and to the effect that while there may be such reasons, they are overridden by certain moral constraints--are considered and rejected. Finally, it is argued that justice provides stronger reasons to perform more traditional medical tasks (treatments), and that therefore genetic enhancements should not play an important role in a public health care system. (+info)
The social nature of disability, disease and genetics: a response to Gillam, Persson, Holtug, Draper and Chadwick.
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The dominance of the biomedically informed view of disability, genetics, and diagnosis is explored. An understanding of the social nature of disability and genetics, especially in terms of oppression, adds a richer dimension to an understanding of ethical issues pertaining to genetics. This is much wider than the limited question of whether or not such technology discriminates. Instead, it is proposed that such technology will perpetuate the oppression and control of people with disability, especially if the knowledge of people with disability is not utilised in bioethical debates. (+info)
Preimplantation genetic diagnosis and the 'new' eugenics.
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Preimplantation genetic diagnosis (PID) is often seen as an improvement upon prenatal testing. I argue that PID may exacerbate the eugenic features of prenatal testing and make possible an expanded form of free-market eugenics. The current practice of prenatal testing is eugenic in that its aim is to reduce the numbers of people with genetic disorders. Due to social pressures and eugenic attitudes held by clinical geneticists in most countries, it results in eugenic outcomes even though no state coercion is involved. I argue that technological advances may soon make PID widely accessible. Because abortion is not involved, and multiple embryos are available, PID is radically more effective as a tool of genetic selection. It will also make possible selection on the basis of non-pathological characteristics, leading, potentially, to a full-blown free-market eugenics. For these reasons, I argue that PID should be strictly regulated. (+info)
History of medicine and concepts of health.
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It was not until the exemplary social reform of the 19th century and the introduction of modern health insurance schemes that people started to consider health as some kind of basic right which could be ensured by insurance and doctors, rather than by individual responsibility. The recent explosion of health system costs in countries like Germany has given rise to an unprecedented situation whereby the limited capacities of insurance systems and state organizations are becoming more and more evident. Health economists are now questioning the feasibility of optimal medical treatment for everybody. One consequence of this situation is that people are being forced to recall the old virtue of individual responsibility for one's own physical and mental well-being. This article examines the nature of health from a historical point of view. The point is made that health is not the same thing as a life free from complaints, although this erroneous belief is wide-spread today. Galen himself identified a neutral physical state between health and illness (neutralitas), that could be observed in many people who could not be described as being either healthy or ill. It is necessary to accept this state as part of the natural fate of humankind and to understand that individual responsibility and the demands on society and insurance companies for well-being or absolute freedom from ailments are not one and the same thing. (+info)
Toward a utility theory foundation for health status index models.
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The axioms of utility theory are restated in terms of health outcomes, and some additional assumptions, consistent with the assumptions implicit in health status index models, are adduced to develop a consistent theory of the utility of health states. On the basis of the axioms and specific assumptions, techniques for measuring the health utility functions of individuals are described, and it is shown how these axioms and assumptions may be used to determine the utility to the individual of health programs that will affect him in various ways. (+info)
Child health interventions in urban slums: are we neglecting the importance of nutrition?
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During the early part of the twentieth century, there were dramatic falls in the mortality rates in many cities in the West. The reasons for this improvement are of considerable relevance today because the conditions which prevailed at that time in cities such as New York are comparable to those prevailing in many slums of the Third World today. Some early studies linked the improvements in health, as measured by mortality rates, to a better level of nutrition. The importance of nutrition is now widely accepted and there are many studies which show the association between nutrient intake and both mortality and morbidity, and in particular between breast feeding and infant mortality rates. It is sometimes assumed that, because nutrition indicators for city populations have improved, there is no longer a major problem of malnutrition in urban areas. However, it is likely that the figures hide disparities through aggregation, and studies in slums rather than cities as a whole give a much less encouraging picture. Poverty is at the root of many of the nutritional and associated health problems, but the children who will be born over the coming decades cannot afford to wait for a new economic order to provide the solution. Through the promotion of breast feeding, education, growth monitoring and food supplementation, necessary help can be targeted at this vulnerable population. (+info)