By I. Pranck. Willamette University.
The quality and robustness of such software is crucial to radiation safety and cheap 50 mg naltrexone fast delivery medicine 75 yellow, clearly generic naltrexone 50 mg on line treatment hyperthyroidism, software must meet acceptable standards. The review is to be performed by the radiological medical practitioners, the medical radiation technologists and the medical physicists, and they would essentially ask themselves the questions: ‘How are we really doing? While requirements for individual monitoring are well established for medical uses of radiation, there is an almost inverse relationship between compliance in being monitored and the likelihood of occupational exposure. Those persons unlikely to receive much dose wear their dosimeters as required, while those with a high likelihood of significant occupational exposure seem to not regularly wear their dosimeters. For example, there is strong evidence that personnel performing interventional cardiology procedures are not being effectively monitored . This situation will only improve, using current types of dosimetry, if monitoring is clearly seen as adding value. One way that this can occur is to use the monitoring results to improve occupational radiation protection in the facility. Without good radiation protection practice, some health professionals could easily exceed the new dose limit. There is a clear need for education and training, provision of appropriate protective tools and, again, monitoring to ensure acceptable occupational radiation protection for the more at risk occupationally exposed personnel for the next decade. It not only sets the basic requirements, it also provides the foundation for enabling further actions. In the coming years, specific guidance on radiation could be provided on the following topics: optimization of radiological protection for new technology in medicine; management of patient and staff protection as a global approach; occupational lens doses and extremity doses; radiation risk communication to patients; justification of some medical procedures including the impact of external factors; tissue reactions during complex interventional procedures; patient dose recording and tracking in imaging; expanding the use of diagnostic reference levels; radiation risk assessment in radiotherapy; requirement for sufficient trained staff to support radiological protection in medical installations. It is also prepared to cooperate with other international organizations and to encourage the use of the best possible science as the foundation for radiological protection in medicine. In September 2001, the Board requested the Secretariat to convene a group of experts to formulate — on the basis of the conference’s findings, conclusions and recommendations — an Action Plan for future international work related to radiological protection of patients, and to submit the Action Plan for approval. The objective of the International Action Plan was to improve patient safety as a whole. The involvement of international organizations and professional bodies was considered crucial to performing the actions and achieving the goals outlined in the Action Plan. In addition, external experts are invited to participate as members of the task groups or working parties that produce the documents on radiological protection recommendations. Technology in medicine is evolving very rapidly and the use of ionizing radiation is likely to increase in the coming years. Not only medical and paramedical personnel but also industry engineers and maintenance professionals are to be considered in this issue. Strategies for optimization in reducing organ doses in the cardiovascular and cerebrovascular systems need to be implemented. Since X rays and radium started to be used in medicine, there has been a gigantic development in diagnosis and therapy practices making use of ionizing radiation. There have also been growing international efforts to improve radiological protection in medicine. Thus, the Bonn conference completed a cycle of unprecedented international cooperation for protecting patients and medical staff against the detrimental effects of radiation exposure. The time seems to be ripe for this paper summing up the achievements and the remaining challenges of radiological protection in medicine, the main purpose being to pursue a future strategy for dealing with these issues. The paper is organized under the old Roman motto veni, vidi, vici in three parts, namely: veni — coming from a successful history; vidi — examining new challenges; and vici — successfully moving towards an international regime for radiation safety in medicine. It is noted, however, that his opinions in this paper do not necessarily reflect those of these bodies. An international radiological protection regime would eventually evolve under the aegis of several prestigious international organizations, becoming a network of science, paradigm and regulatory standards. What follows is a summary account of this successful history, with a focus on protection in medicine, particularly of patients. The early stages At the beginning of the twentieth century, the knowledge of radiation and its effects was limited and the main concern was protecting the staff practising the medical use of the sole radiations being employed at that early time, namely X rays and radium emissions. Those early recommendations state that: “the dangers of over-exposure to X rays and radium can be avoided by the provision of adequate protection and suitable working conditions. It is the duty of those in charge of X ray and radium departments to ensure such conditions for their personnel” (para. That early recommendation states that “screening stands and couches should provide adequate arrangements for protecting the operator against scattered radiation from the patient” (para. The early advice included some curious counsel on ergonomics, such as that X ray departments should not be situated below groundfloor level and that all rooms (including dark rooms) should be provided with windows affording good natural lighting and ready facilities for admitting sunshine and fresh air whenever possible, and with adequate exhaust ventilation capable of renewing the air of the room not less than 10 times an hour, and with air inlets and outlets arranged to afford cross-wise ventilation of the room, and, surprisingly, they should preferably be decorated in light colours (paras 3–6 of Ref.
Idiopathic and L-tryptophan-associated eosino- philic fasciitis before and after L-tryptophan contamination discount naltrexone 50 mg visa medicine 95a pill. Interactions among leucine buy naltrexone 50mg fast delivery treatment bulging disc, isoleucine, and valine with special reference to the branched-chain amino acid antagonism. Threonine require- ment of healthy adults, derived with a 24-h indicator amino acid balance tech- nique. Moderate homocysteinemia— A possible risk factor for arteriosclerotic cerebrovascular disease. Brattstrom L, Israelsson B, Norrving B, Bergqvist D, Thorne J, Hultberg B, Hamfelt A. Impaired homocysteine metabolism in early-onset cerebral and peripheral occlusive arterial disease. Development of a minimally invasive protocol for the determination of phenylalanine and lysine kinetics in humans during the fed state. Determination of amino acid require- ments by indicator amino acid oxidation: Applications in health and disease. Proline ameliorates arginine deficiency during enteral but not parenteral feeding in neonatal piglets. Treatment of episodic hyperammonemia in children with inborn errors of urea synthesis. Relation of protein content of mother’s diet during pregnancy to birth length, birth weight, and condition of infant at birth. Longitudinal changes in milk composition of mothers delivering preterm and term infants. Cysteine-induced enhancement of lipid peroxidation in substantia nigra: Comparative effect with exogenous administration of reduced glutathione. Variation in endogenous nitrogen excretion and dietary nitrogen utilization as determinants of human protein requirement. Increased protein requirements in elderly people: New data and retrospective reassessments. Effects of resis- tance training and dietary protein intake on protein metabolism in older adults. The recommended dietary allowance for protein may not be adequate for older people to maintain skeletal muscle. Stimulation of pituitary hormone secretion by neurotransmitter amino acids in humans. Elderly women accommo- date to a low-protein diet with losses of body cell mass, muscle function, and immune response. Methionine overcomes neural tube defects in rat embryos cultured on sera from laminin- immunized monkeys. Human serum teratogenicity studied by rat embryo culture: Epilepsy, anticonvulsant drugs, and nutrition. Influence of pro- gressive tumor growth on glutamine metabolism in skeletal muscle and kidney. Comparative nitrogen balance study between young and aged adults using three levels of protein intake from a combination wheat-soy-milk mixture. Protein turnover in the human fetus studied at term using stable isotope tracer amino acids. Determination of anserine, carnosine, and other histidine compounds in muscle extractives. Direct measurement by continuous intravenous tracer infusions of L-[ring-2H ] 13 5 phenylalanine and L-[1- C] tyrosine in the postabsorptive state. Methionine and neural tube closure in cultured rat embryos: Morphological and biochemical analyses. Effects of dietary and intraperitoneal excess of L-lysine and L-leucine on rat pregnancy and offspring.
Library of Congress Cataloging-in-Publication Data Dietary reference intakes for energy generic naltrexone 50mg mastercard xanthine medications, carbohydrate naltrexone 50 mg with mastercard medications keppra, fiber, fat, fatty acids, cholesterol, protein, and amino acids / Panel on Macronutrients, Panel on the Definition of Dietary Fiber, Subcommittee on Upper Reference Levels of Nutrients, Subcommittee on Interpretation and Uses of Dietary Reference Intakes, and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes, Food and Nutrition Board. The serpent has been a symbol of long life, healing, and knowledge among almost all cul- tures and religions since the beginning of recorded history. The serpent adopted as a logo- type by the Institute of Medicine is a relief carving from ancient Greece, now held by the Staatliche Museen in Berlin. The National Academy of Sciences is a private, nonprofit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research, dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its mem- bers, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engi- neering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. The Institute of Medicine was established in 1970 by the National Academy of Sciences to secure the services of eminent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. The National Research Council was organized by the National Academy of Sciences in 1916 to associate the broad community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has become the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. His expertise in protein and amino acid metabolism was a special asset to the panel’s work, as well as a contribution to the understanding of protein and amino acid requirements. Close attention was given throughout the report to the evidence relating macronutrient intakes to risk reduction of chronic disease and to amounts needed to maintain health. Thus, the report includes guidelines for partitioning energy sources (Acceptable Macronutrient Distribution Ranges) compatible with decreasing risks of various chronic diseases. Thus, although governed by scientific rationales, informed judgments were often required in setting reference values. The quality and quantity of information on overt deficiency diseases for protein, amino acids, and essential fatty acids available to the com- mittee were substantial. Unfortunately, information regarding other nutri- ents for which their primary dietary importance relates to their roles as energy sources was limited most often to alterations in chronic disease biomarkers that follow dietary manipulations of energy sources. Also, for most of the nutrients in this report (with a notable exception of protein and some amino acids), there is no direct information that permits estimating the amounts required by children, adolescents, the elderly, or pregnant and lactating women. Dose–response studies were either not available or were suggestive of very low intake levels that could result in inadequate intakes of other nutrients. These information gaps and inconsistencies often precluded setting reli- able estimates of upper intake levels that can be ingested safely. The report’s attention to energy would be incomplete without its substantial review of the role of daily physical activity in achieving and sustaining fitness and optimal health (Chapter 12). The report provides recommended levels of energy expenditure that are considered most com- patible with minimizing risks of several chronic diseases and provides guid- ance for achieving recommended levels of energy expenditure. Inclusion of these recommendations avoids the tacit false assumption that light sedentary activity is the expected norm in the United States and Canada. With more experience, the proposed models for establishing reference intakes of nutrients and other food components that play significant roles in pro- moting and sustaining health and optimal functioning will be refined. Also, as new information or new methods of analysis are adopted, these reference values undoubtedly will be reassessed. Many of the questions that were raised about requirements and recommended intakes could not be answered satisfactorily for the reasons given above. Thus, among the panel’s major tasks was to outline a research agenda addressing information gaps uncovered in its review (Chapter 14). The research agenda is anticipated to help future policy decisions related to these and future recommendations. This agenda and the critical, com- prehensive analyses of available information are intended to assist the private sector, foundations, universities, governmental and international agencies and laboratories, and other institutions in the development of their respective research priorities for the next decade.
Another line of evidence often cited to indicate that dietary fat is not an important contributor to obesity is that although there has been a reduction in the percent of energy from fat consumed in the United States discount 50 mg naltrexone mastercard medicine dictionary prescription drugs, there has been an increase in energy intake and a marked gain in average weight (Willett 50mg naltrexone with amex medications similar buspar, 1998). Survey data showed an increase in total energy intake over this period (McDowell et al. Another study that used food supply data showed that fat intake may indeed be rising in the United States (Harnack et al. Several mechanisms have been proposed whereby high fat intakes could lead to excess body accumulation of fat. Foods containing high amounts of fat tend to be energy dense, and the fat is a major contributor to the excess energy con- sumed by persons who are overweight or obese (Prentice, 2001). The energy density of a food can be defined as the amount of metabolizable energy per unit weight or volume (Yao and Roberts, 2001); water and fat are the main determinants of dietary energy density. Energy density is an issue of interest to the extent that it influences energy intake and thus plays a role in energy regulation, weight maintenance, and the subsequent development of obesity. Three theoretical mechanisms have been identified by which dietary energy density may affect total energy intake and hence energy regulation (Yao and Roberts, 2001). Some studies suggest that, at least in the short- term, individuals tend to eat in order to maintain a constant volume of food intake because stomach distension triggers vagal signals of fullness (Duncan et al. Thus, consumption of high energy-dense foods could lead to excess energy intake due to the high energy density to small food volume ratio. A survey of American adults reported that taste is the primary influence for food choice (Glanz et al. In single-meal studies, high palatability was also associated with increased food consumption (Bobroff and Kissileff, 1986; Price and Grinker, 1973; Yeomans et al. These results suggest that high energy-dense foods may be overeaten because of effects related to their high palatability. The third mechanism is that energy-dense foods reduce the rate of gastric emptying (Calbet and MacLean, 1997; Wisen et al. This reduction, however, does not occur proportionally to the increase in energy density. Although energy-dense foods reduce the rate at which food leaves the stomach, they actually increase the rate at which energy leaves the stomach. Thus, because energy-containing nutrients are digested more quickly, nutrient levels in the blood fall quicker and hunger returns (Friedman, 1995). While a subjective measure, highly palatable meals have also been shown to produce an increased glycemic response compared with less palatable meals that contain the same food items that are com- bined in different ways (Sawaya et al. This suggests a generalized link among palatability, gastric emptying, and glycemic response in the underlying mechanisms determining the effects of energy density on energy regulation. Researchers have used instruments such as visual analogue scales to measure differences in appetite sensations (e. A number of studies have been conducted in which preloads of differing energy density were given and hunger and satiety were measured either at the subsequent meal or for the remainder of the day. In the studies that administered preloads that had constant volume but different energy content (energy density was altered by chang- ing dietary fat content), there was no consistent difference in subsequent satiety or hunger between the various test meals (Durrant and Royston, 1979; Green et al. However, in those studies using isoenergetic preloads that differed in volume (energy density was altered by changing dietary fat content), there was consistently increased satiety and reduced hunger after consumption of the low energy-dense preload meals (i. It has been reported, however, that diets low in fat and high in carbo- hydrate may lead to more rapid return of hunger and increased snacking between meals (Ludwig et al. Because individuals were blinded to the dietary content of the treatment diets, the results from these studies demonstrate the short- term effects of energy density after controlling for cognitive influences on food intake. It is important that cognitive factors are taken into account during the interpretation of results of preload studies. When individuals were aware of dietary changes, they generally (Ogden and Wardle, 1990; Shide and Rolls, 1995; Wooley, 1972), but not always (Mattes, 1990; Rolls et al. In well-controlled, short-term intervention studies lasting several days or more, high fat diets were consistently associated with higher spontaneous energy intake (Lawton et al. From short- and longer-term studies, volunteers consistently con- sumed less dietary energy on low fat, low energy dense diets compared to high energy-dense diets (Glueck et al.
Skin grafts may speed healing order naltrexone 50 mg mastercard medicine 93, but only if venous pres- Clinically lesions can be divided into two categories: sure is reduced buy 50 mg naltrexone with mastercard symptoms 3 days after embryo transfer, e. Surgery to remove r Acyanotic heart disease, which include the left to right incompetent veins before ulceration occurs. Deﬁnition Prevalence Abnormal defect in the ventricular septum allowing pas- Up to 1% of live born infants are affected by some form sage of blood ﬂow between the ventricles. Chapter 2: Congenital heart disease 85 Age continued large left to right shunt, the combination of Congenital increased pulmonary blood volume and high-pressure shear forces causes hypertrophy and deposition of col- Sex lagen in the walls of pulmonary arterioles. Eventually M = F these changes become irreversible and pulmonary hy- pertension develops, usually during childhood. The re- sultant high pressure in the right side of the heart causes Aetiology areductionand eventual reversal of the shunt with as- In most cases the aetiology is unknown but may include sociated development of cyanosis termed Eisenmenger maternal alcohol abuse. On ex- r Small defects result in little blood crossing to the right amination there is usually a pulmonary ejection mur- sideoftheheartandnohaemodynamiccompromise– mur and there may be tachypnoea and tachycardia if ‘maladie de Roger’. The murmur is, however, causes a loud pulmonary component to the second quieter as there is less turbulent ﬂow. Initially increased pulmonary blood ﬂow does not cause arise in pressures within the pulmonary circulation Investigations due to the vascular compliance. If, however, there is a r Chest X-ray: Abnormalities are only seen with large defects when cardiomegaly and prominent pul- monary vasculature may be seen. Measurement of the size of the defect and the blood ﬂow allows prediction of the outcome. The shunting of blood from left to right increases the volume of blood passing through the right side of the Incidence heart leading to right ventricular volume overload and 10% of congenital heart defects. Prolongedhigh volume blood ﬂow through lungs can occasionally lead Sex to pulmonary hypertension due to changes in the pul- F > M monary vasculature similar to ventricular septal defects (see page 84). Aetiology Defects in the ostium primum occur in patients with Clinical features Down syndrome often as part of an atrioventricular sep- Atrialseptaldefectsareoftenasymptomaticinchildhood tal defect. On examination Pathophysiology there is a ﬁxed widely split second heart sound due to the The atrial septum is embryologically made up of two high volumes ﬂowing through the right side of the heart parts: the ostium primum and the ostium secundum, and the equalisation of right and left pressures during which forms a ﬂap over the defect in the ostium pri- respiration. A diastolic murmur may through the fossa ovalis and hence shunts blood away also occur due to ﬂow across the tricuspid valve. In normal individuals Rarely patients may present with paradoxical emboli at birth the vasculature within the lungs dilate at birth (where thrombus from a deep vein thrombosis crosses and hence the right heart pressures fall. Once the left the atrial septal defect and causes stroke or peripheral atrial pressure exceeds the right, the ostium secundum arterial occlusion). Ostium secundum tends to produce right axis Chapter 2: Congenital heart disease 87 deviation, whereas ostium primum produces left axis Neonatal coarctation is often associated with a patent deviation. Eighty per cent of cases occur in association with a Management bicuspid aortic valve. The defect may be closed using an umbrella-shaped Clinical features occluder placed at cardiac catheterisation. Traditional Proximal hypertension may cause headache and dizzi- open surgical repair requires cardiopulmonary bypass ness, distal hypotension results in weakness and poor pe- and may use a pericardial or Dacron patch to close the ripheral circulation. Surgicalinterventioninostiumprimumdefectsis are weak or absent and there is radiofemoral delay. Four- morecomplexduetoinvolvementoftheatrioventricular limb blood pressure measurement will demonstrate the valves. Coarctation of the aorta Investigations Deﬁnition r Chest X-ray may show left ventricular hypertrophy Localised narrowing of the descending aorta close to the and rib notching due to dilated intercostal arteries site of the ductus arteriosus. Pathophysiology Coarctation of the aorta tends to occur at the site of the ductus/ligamentus arteriosus, which is usually opposite Management the origin of the left subclavian artery (see Fig. The Surgical treatment is used in the majority of cases and left ventricle hypertrophies to overcome the obstruction is an emergency in coarctation complicated by a patent and cardiac failure may occur. The chest is opened by left lateral tho- develops with hypotension in the lower body. Prognosis Without treatment 50% of patients die within the ﬁrst year of life from cardiac failure and complications of hypertension such as intracranial bleeds. This reduces the right to left intracardiac shunt and provides some symptomatic relief.