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The blocks rapidly fell into place - Sue had missed her period 2 weeks ago and had just been building up the courage to tell her husband and boys cheap levitra extra dosage 40mg visa erectile dysfunction circumcision. She had developed colicky abdominal pain yesterday and this morning it had got much worse purchase levitra extra dosage 60mg with mastercard jack3d causes erectile dysfunction. Her hands felt cold to touch and she had a rapid thready pulse at 125, the lower half of her belly was rigid and extremely tender. She didn’t really know where to start, Sue needed surgery, and that wasn’t an option. She drew a iv cannula from her bag - it wasn’t actually a cannula - it was the needle from an old cannula - bleached, boiled and sharpened - as sterile as possible - gone where the plastic cannulas - she was back to leaving the metal needles in veins. Sue was lean and muscular and despite her blood loss, several veins popped up as she applied the tourniquet and Alex easily cannulated her. She reached into her bag and pulled out a small jar of coarse brown crystals, a bottle of sterile water, a 10 ml glass syringe, and needles and began the process of making up some heroin. She had a basic idea of the process from her university chemistry and combined with a bit of street knowledge - she had had a go. She had been at medical school at the time, and she remembered talking in clinical chemistry about how they had been extracting the heroin - it was amazingly easy. So now she had a small jar a granular black powder - it probably wasn’t that pure – mostly heroin – but with a small mix of the assorted other opiates and alkaloids found in the poppy. On the few occasions she had used it, it had been very effective - a little trial and error with the dosing - but effective. The main problem now was sterility and removing all the insoluble rubbish - she had adopted - 205 - Survival and Austere Medicine: An Introduction basically the same techniques the addicts had used – but hopefully slightly more sterile - dissolve it in distilled water, filter it as best she could – she had a small supply of cigarette filter paper she had salvaged for the purpose and then heated it to sterilize it. Not perfect by any means, but like everything else in her world now – near enough frequently had to be good enough. But over the next few minutes, her moaning settled and she seemed more comfortable. There was some down in the clinic, but they were too cumbersome to cart around in her medical backpack. The boy reappeared, in a surprisingly short period of time, with one of the farmers from the village and his horse and cart (really a cut down car with a removed engine and a substituted horse) and they half carried and half walked Sue to the back bed of the cart. They moved off slowly down the valley in the cart, with Sue moaning softly as they moved over the broken tar sealed road, Alex again was trying to think what to do next. Always she arrived at the same conclusion – that while setting fractures and perhaps performing an amputation might be possible, she wasn’t ever going to be able to perform open abdominal surgery – and anyone who needed it was going to die. But now faced with Sue Hanson, lying there in front of her, it didn’t seem so black and white anymore. The first 500mls of normal saline had nearly run through, and Sue’s heart rate had come down and the volume of her pulse seemed stronger. Although this didn’t bother her overly, while Sue was still bleeding from her ruptured ectopic she didn’t want to push her blood pressure up anyway – it would just pop what clot might have formed and encourage more bleeding – more the moment, as long as she had a radial pulse and was awake – that was enough – she didn’t need litres of fluid – she needed an operation. The problem had been how to manufacture it and keep it sterile using a pretty rudimentary set-up. Despite the devastating nature - 206 - Survival and Austere Medicine: An Introduction of the “strike”, they hadn’t been completely driven back to the Stone Age, and while she didn’t have access to proper laboratory equipment, early on in there foraging they had striped the county school of much of its science equipment. This had meant that she had a good number of flasks, beakers, test tubes, and bungs and a small glass condensing coil – most useful of all was an old-style hanging scale, with weights for 1-100gms. This motley collection of equipment had enabled her to produce the heroin and also produce small batches of intravenous fluids. Alex had enlisted Tom, the community brewer – he had over the years established a successful little beer brewery and also a still for making various spirits – on which he also made her high proof medical alcohol. His knowledge of brewing and distilling had been and still was vital in her primitive pharmaceutical production. They had first double distilled water to try and get rid of as many impurities as possible. To this they had added the carefully measured out salt – almost certainly not 100% Sodium Chloride – but hopefully pretty pure. Having scrubbed and sterilized the flasks, using the same method they were using for canning, they were filled with the filtered saline solution and the rubber bung inserted. Then they had used the large pressure cooker they had for canning to heat the bottles to 122 degrees for 30 minutes. Alex was happy that when manufactured the saline was sterile, she didn’t really know how long that sterility was going to last. Since the actual production wasn’t that arduous and only took a couple of hours, she had decided to err on the side of caution and had determined a shelf life of 3 months on it. Again resorting to primitive science she had tried some basic tests to check the sterility – at one, three and six months. This had involved injecting 10 mls of the saline into a poor unsuspecting bunny from the communities “rabbit ranch” and seeing what happened – even at six months post production the rabbit didn’t seem to suffer any ill effects from its run in with the home made iv fluids – not a 100% fool proof purity test – but better than nothing. Her and one of the farmers had also experimented on one of the farm dogs to try and get a feel for the dosing for the heroin – they had started off injecting small amounts – so increasing it – seeing how much it took to make the dog drowsy and then how much it took to depress its breathing. From these experiments she worked backwards to come up with a rough grams/kg dose – but she had also learnt that each batch of heroin was slightly different, so the element of trial and error was still there. Alex found it distasteful to be experimenting with doses and sterility on animals – but like all the survivors she was a realist about what had to be done to survive. So here she was, standing in her clinic contemplating what even before the impact had been major surgery – and she was both surgeon and anaesthetist! For the second time today she was cursing her own stupidity for not even thinking of an apprentice before now. Kate wasn’t an apprentice, she was a 68 year old, old school farmers wife - she could stand the sight of blood and had helped two of her daughters have homebirths, back before the Impact - back before it became "fashionable" again, now there was no alternative - so she at least had a few medical clues and didn’t faint at the sight of blood. She had helped her on a - 207 - Survival and Austere Medicine: An Introduction few occasions before and Alex had briefed her about what she was going to do, so she had a rough idea of what she was going to need to do to help. Alex injected another couple of mls of heroin; she was still worried about giving her too much and dropping her blood pressure to her boots. She turned to her instruments - they were a real mix (like everything else) – she had one good set of quality suture instruments they had foraged early on – a needle holder, two forceps, a pair of clips and some scissors - and a average quality university science dissection kit, the most handy item being a reusable scalpel - which she had just sharpened - before having boiled the whole lot for 20 mins. She had no gloves, but catching a viral infection from a patient was really the least of her problems anyway – what choice did she have. She checked her hands and fortunately had no open cuts or grazes – although again it mattered little – she had to do the surgery and while it was good she had no open wounds she would have continued anyway. Wet, lather, scrub, rinse, repeat – hands and forearms – she had always questioned the merits of scrubbing for 5 minutes when you were going to be wearing 2 layers of latex gloves, but now, under these circumstances she understood clearly the origin of these old surgical rituals – with no gloves and very limited antibiotics, she want to reduce as much as she could any bugs living on her hands. When she had finished washing her hands she had Kate pour alcohol over them, and she allowed it to evaporate off as see pondered what she was about to do – she pushed all of her thoughts of self doubt to the side and took a deep breath.

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What to do… Surgical procedures such as lung volume reduction surgery or lung transplantation may be helpful for ✔ Stop smoking and avoid smoke exposure cheap 60 mg levitra extra dosage with amex erectile dysfunction drug companies. The information appearing in this series is for educational purposes only and should not be used as a substitute for the medical advice one one’s personal health care provider generic levitra extra dosage 40 mg with visa erectile dysfunction drug stores. Two principal approaches to improving women’s nutritional status are outlined: nutritional supplementation and behavior change. They include cardiovascular disease, cancers, respiratory diseases, diabetes, obesity, and musculoskeletal disorders. Following birth, environmental exposures during infancy, childhood and adult life can then further modify the risk of developing these chronic diseases in later life. The approach sees optimization of growth and development as being fundamental to the prevention of disease. A Lifecourse Approach Lifecourse epidemiology is the study of the long-term effects on later health and disease risk ofLifecourse epidemiology is the study of the long-term effects on later health and disease risk physical or social exposures during gestation, childhood, adolescence, young adulthood, and later adultof physical or social exposures during gestation, childhood, adolescence, young adulthood, and life. The aim of the approach is to find out about processes (biological, behavioral, and psychosocial)later adult life. The aim of the approach is to find out about processes (biological, behavioral, and that operate across an individual’s lifecourse or across generations, to influence risk of disease. The lifecourse approach is increasingly focused on the development and evaluation of interventions to improve health and prevent disease. Improved understanding of the mechanismsThe lifecourse approach is increasingly focused on the development and evaluation of that underlie associations between early life and later disease is facilitating the development ofinterventions to improve health and prevent disease. Improved understanding of the mechanisms that interventions that can optimize growth and development of body composition, and maintainunderlie associations between early life and later disease is facilitating the development of interventions physical and cognitive function at all stages of childhood and adolescence. Figure 1 accumulated effects of inadequate responses to new challenges (brown triangle). The greatestshows how risk increases as a result of declining plasticity (green triangle) and the resulting increase in risk is acquired in adult life. The greatest increase Maternal factors such as diet and body composition will influence risk of disease before and duringin risk is acquired in adult life. Fetal, infant and childhood nutrition and development will influence risk of diseasefactors such as diet and body composition will influence risk of disease before and during pregnancy. Taking a lifecourse approach enables early identification of phenotypes and markers ofFetal, infant and childhood nutrition and development will influence risk of disease thereafter. Taking a risk, and this in turn facilitates the development of nutritional and other lifestyle interventionslifecourse approach enables early identification of phenotypes and markers of risk, and this in turn aimed at preventing disease. Relatively modest interventions in early life (red area) can have a largefacilitates the development of nutritional and other lifestyle interventions aimed at preventing disease. Later intervention (pink area) can have an impact on diseaseRelatively modest interventions in early life (red area) can have a large effect on disease risk later risk for vulnerable groups (pink arrow). Later intervention (pink area) can have an impact on disease risk for vulnerable groups investment but can lead to large reductions in disease risk. Adulthood No intervention Chronic Late intervention non-communicable impactful for disease risk vulnerable groups Late intervention Childhood & Earlier intervention adolescence improves functional capacity & responses Mother to new challenges & infant Early intervention Life course Developmental plasticity Inadequate response to new challenges Figure 1. Observational Evidence of a Link between Early Development and Later Disease The last three decades has seen the emergence of evidence demonstrating the importance of the environment during early life for the establishment of disease risk in later life and in future generations. Observational Evidence of a Link between Early Development and Later Disease The last three decades has seen the emergence of evidence demonstrating the importance of the environment during early life for the establishment of disease risk in later life and in future generations. In Hertfordshire, sixteen thousand men and women born between 1911 and 1930 were traced. Death rates from coronary heart disease fell steadily across the birth weight distribution such that rates at the higher end of the distribution were roughly half those at the lower end [4]. Findings from the Swedish cohort study, which followed up 14,611 babies, also supported the inverse association between cardiovascular disease and birth weight [5]. The associations of birth weight with these diseases were independent of lifestyle risk factors, including smoking and alcohol intake, and of socio-economic status. The developmental origins model of disease pathogenesis is supported by biological evidence from animal experiments. These have shown that alteration of maternal diet during pregnancy can modify offspring physiological processes, and that these modifications are lasting rather than transient [6]. Such a phenomenon is an example of phenotypic plasticity where a genotype can give rise to different physiological or morphological states depending on the prevailing environmental conditions during development. Studies in experimental animals have made it clear that the long-term effects of early life nutrition act through developmental changes to organs and tissues such as the pancreas, liver, kidneys, skeletal muscle and adipose tissue. Newborn size (equivalent to birth weight in human studies) is frequently used as an indicator of the intra-uterine experience, because it is easy to measure, but can only be a crude proxy of these changes at tissue level. Animal experiments have shown that overfeeding mothers with high fat or high energy diets, leading to maternal diabetes and obesity, will increase insulin resistance, diabetes and cardiovascular changes in their offspring [7,8]. Recently, there has been accumulating evidence that paternal diet, body composition and health can also affect the health of the offspring [9]. Low birth weight, an indicator of poor nutrition in utero, is associated with higher infant mortality, poorer educational outcomes in childhood and poorer long term health [11]. Social, psychological and occupational exposures during infancy, childhood and adult life will modify risk of ill health and disease. Maternal Nutrition Observational evidence of a link between early life and later disease has led to an interest in maternal influences on the development of the fetus. A girl or woman’s nutritional status before and during pregnancy influences outcomes both for her pregnancy and for the developing fetus [12]. It also has a strong influence on risk of pre-term delivery and impaired growth and development in utero and after birth. Recent studies have shown that prenatal exposure to gestational diabetes could lead to epigenetic alterations that increase the risk of type 2 diabetes later in life. In India, for example, findings of the Pune maternal nutrition study suggest that micronutrient deficiencies (such as vitamin B12) can also lead to low birth weight and an increased risk of later diabetes [13]. Healthcare 2017, 5, 14 4 of 12 Maternal undernutrition is usually caused by food shortage or economic hardship which leads to food insecurity and result in inadequate intake of nutrients. Exposure to undernutrition in utero is associated with low birth weight and stunting in childhood, which are in turn associated with shorter adult height and reduced economic productivity [14,15]. Undernutrition in utero also has adverse effects on cognitive development and so is also associated with lower levels of educational attainment. Overnutrition occurs when the energy consumed outstrips energy expended and usually leads to overweight and obesity. For women during pregnancy, overnutrition leads to greater risk of gestational diabetes and hypertensive disorders of pregnancy. For the fetus, maternal gestational diabetes leads to an increased risk of macrosomia, high blood glucose and insulin and these are associated with neonatal hypoglycemia, congenital anomalies, preterm birth, stillbirth and neonatal death.

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Kidney Disorders If you have a history or presence of a kidney infection discount 40mg levitra extra dosage overnight delivery erectile dysfunction mayo, limit the initial amount of oral urine therapy you take to small doses such as 1-5 drops once or twice a day order 60 mg levitra extra dosage with visa erectile dysfunction jet lag, or use a homeopathic dilution as described in the section on. Also, check your acidity levels with pH strips, and begin urine therapy when your acid levels have normalized or decreased substantially. Refer to these studies for directions and 196 again, begin with one or two drops and then gradually increase the number of drops, or as Wilson suggests, take the drops until you can no longer sense the urine taste or temperature. Dunne, are also excellent for allergies, as you can preserve the urine collected at the height of allergy symptoms for long term treatment of the allergy. Food Poisoning Several of the research studies show that urea is a proven anti- bacterial agent (Drs. Fasting Fasting on urine is an excellent therapy that can produce extraordinary results, especially for intractable diseases and tough chronic conditions, but always work into a fast slowly. Begin with oral drops for two to three weeks, increase your dosage to 1- 3 ounces during the next two or three weeks, and begin fasting the following week. When I first started urine therapy, I was so seriously ill with so many different conditions and in such extreme pain, that I rushed into aweek-long fast on urine and water alone. Pushing your body too quickly can produce often severe detoxifying symptoms such as headaches, fever, nausea, depression, or fatigue that you can lessen or avoid by. During the fast, ingest as much urine as you pass during the day until it becomes completely dear; stop ingesting for a few hours 197 and then resume. Decrease or stop your intake at night and begin again when you awake in the morning. Force-drinking water, in addition to urine ingestion, may also stress the kidneys. Combine urine fasting with urine skin massages, particularly on the face, neck and feet. John Armstrong insisted on this method because he felt that it gave extra nourishment to the body while fasting and eliminated possible headaches and nausea. When breaking the fast, start by eating a simple homemade fresh vegetable soup broth such as one made of fresh kale, carrots, fresh green leeks, scallion tops and a little fresh ginger. Eat only the broth for a day or two, the broth and vegetable the next day, and begin gradually adding in more vegetables and carbohy-drates such as rice and millet over the next few days. Short periods of fasting (1-3 days) can be an extremely effective method for cleansing and healing the body; long fasts should always be under-taken with caution and supervision. Homeopathy and Urine Therapy In the course of using urine therapy, I found that combining the therapy with homeopathic medicines in particular can produce incredible results, even for the toughest, most stubborn chronic conditions. Severely weakened, debilitated, chronically ill individuals often develop extreme sensitivities to ordinarily helpful herbal, vitamin, mineral and other medicinal preparations, but are able to tolerate homeopathic medidnes very well. Homeopathic medicines are simply extremely diluted natural sub- stances such as plants, minerals, etc. A homeopathic medicine is prepared by diluting a minute amount of a particular natural substance with water; the dilution is shaken several tunes and then alcohol may be added to the solution as a preservative. You can take the homeopathic medicine in its liquid form, or as a small sucrose pill 198 which has been saturated with the liquid. Homeopathic urine is excellent for children and may be helpful to those with extreme sensitivities. It also provides a means of preserving urine collected during the first stages or the onset of illness, at,which time the urinary antibodies and iinmune defense agents are most reported to be most numerous and active. Pre-prepared homeopathic urea can also be purchased, although this would contain only urea and none of the antibodies or immune factors of a whole urine homeopathic preparation. The traditional book for selecting and using homeopathic medicines is referred to as the Materia Medica, which contains a listing of the remedies and Lndications for their use. To 5 mis (1/6 of an ounce) of distilled water in a sterile bottle add one drop of fresh urine. Place three drops under the tongue hourly until there is obvious improvement or temporary exacerbation of symptoms. For beginners who feel unsure about how to use homeopathy, the best book I have found as an overall introduction to self-care through home-opathy is The Fanfily Guide to Homeopathy, Symptoms and Natural Solutions, by Dr. This book is an extraordinary adjunct to urine therapy and contains helpful material about a wide range of disorders that I have never found anywhere else. When using homeopathy, you have a choice of two different dilutions referred to as "x " potencies or "c " potencies. I have found that the c potencies are excellent for home use, as their effect seems more pronounced than the commercial preparations; many homeopathic doctors also prefer the “c” potencies. Combining homeopathy with urine therapy was, for me, incredibly effective for a wide variety of serious disorders as well as for mild disorders such as headaches, colds, indigestion, etc. External Use Skin Applications Applying urine to the skin is an excellent treatment for every 200 imaginable type of skin disorder including all rashes, eczema, psoriasis, acne, etc. The urea in urine, as the research studies demonstrated, is also excellent for cosmetic use as an overall skin beautifier and moisturizer. Use either fresh or old urine for skin applications, although old urine has a higher ammonia content and has been found to be more effective in treating many stubborn skin disorders such as eczema or psoriasis. Discard the pad and saturate another clean pad with fresh urine and reapply, lightly patting and soaking the affected area. Continue reapplying in this manner for 5-10 minutes or as many times as desired - the more that the affected area is treated, the better. Secure a clean soaked pad to the affected area with a gauze or cotton ~vrap and leave secured for several hours for additional healing. These urine packs are also incredibly effective for any type of insect sting, bite or poison oak or ivy. Another method is to pour old or fresh urine into clean, plastic spray bottle and spray the rash, eczema, etc. Skin Massages Always augment your use of oral urine therapy with skin massages particuJariy on the face, neck and feet John Armstrong recommended this practice especially when fasting for an acute condition, and people who use it, swear by it. These massages have a tonifying, refreshing, relaxing effect and are said to allow for gradual absorption of urine nutrients through the skin. Pour either old or fresh urine into a wide, shallow container and dip your hands into the liquid. Shake off excess, then vigorously massage into a small area of skin anywhere on the body until hands and skin are dry. Rewet hands and begin massaging another area until dry; repeat this step until all skin areas have been well massaged. If your own urine is dark, turbid or abnormal looking, wait until you have used the urine internally over the course of two or three days, at which time the urine usually appears clear and can then be used for massages. Urine from a normal healthy person other than yourself may also be used for your external massage. If you are a heavy smoker, or are taking therapeutic or recreational drugs, do not use your own urine externally or internally (or use only extremely small amounts). For cosmetic use or moisturizing, pour a very small amount of nor mal fresh urine or urme which has been stored, for a day or two into your hand and massage lightly into the skin until dry; then pour additional urine into your hand, massage it into another area of the skin until dry and so on. Also, you can add a few drops of urine to a small amount of your moisturizing cream each time you apply the cream. As the research studies show, urea replenishes the water content of the skin because it binds hydrogen and attracts moisture to the skin in a way that no mineral oil or glycerin-based lotions or creams can.

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Moreover discount levitra extra dosage 40 mg on-line erectile dysfunction co.za, each method has peculiar theoretical and practical disadvantages levitra extra dosage 40 mg visa erectile dysfunction and high blood pressure, thus the level of consis- tency of estimates based on different approaches should be examined. Nitrogen Balance Method This classical method is discussed earlier in more detail under “Selection of Indicators for Estimating the Requirement for Protein (Nitrogen). Many explanations have been put forward for the lower results using nitrogen balance methodology, including the fact that excess nonprotein energy may have been used in many nitrogen balance studies (Garza et al. The design of that study allowed for the determination of between- individual variance by studying each individual at several levels of lysine intake. In fact, within the large nitrogen balance and amino acid require- ment literature, only one other study (Reynolds et al. The reanalysis of the 1956 Jones study produced an estimate of nitrogen equi- librium for lysine of 30 mg/kg/d, which is comparable to the values derived by the other methods described below (Rand and Young, 1999). In addition, most of the classic amino acid work using nitrogen balance (Leverton et al. Unfortunately, for infants and children the only data available are those based on nitrogen balance, and considerable uncertainty about the accuracy of the estimates remains. However, recent factorial estimates are in reasonable agreement with the nitrogen balance estimates (Dewey et al. Plasma Amino Acid Response Method This method was the first that focused on the physiology of the indi- vidual amino acid (Longnecker and Hause, 1959; Munro, 1970). The reasoning behind this approach is that when the intake of the test amino acid is below its dietary requirement, then its circulating concentration is not only low, but also is relatively insensitive to changes in intake. As intakes of the target amino acid approach the requirement level by increasing the intake of the limiting amino acid, the plasma level of the amino acid starts to increase progressively (see Figure 10-4). The point at which the “constant” portion of the relationship between intake and plasma concen- tration intersects the linear portion is considered to be an estimate of the requirement. A variation on this method involves the examination of the changes in the plasma concentration of the test amino acid as the adult moves from the post absorptive to the fed state post-consumption (Longnecker and Hause, 1961). The main difficulty is that amino acid metabolism is so complex that factors other than the level of amino acid intake, such as gastric emptying time, can influence its concentration (Munro, 1970). Furthermore, the relationship between the intake of the amino acid and its circulating concentration is not necessarily bilinear, so it is difficult to determine a “breakpoint” (Young et al. Although in some regards this problem applies also to the oxidation methods discussed below, over the last 20 years these later methods have supplanted plasma amino acid concentration–based approaches. This marked a major theoretical advance over the nitrogen balance and plasma amino acid response methods. Thus by analogy to the 2 concentration method, it is assumed that below the requirement the test amino acid is conserved and that there is a low constant oxidation rate, but once the requirement is reached, the oxidation of the test amino acid increases progressively. The most salient problem arises from the reliance on the determination of a breakpoint in the oxidation of the test amino acid. However, at these low dietary intakes, the intake of the infused labeled amino acid becomes significant in relation to dietary intake. This limits its use largely to the branched chain amino acids, phenylalanine, and lysine. Other amino acids, such as threonine and tryptophan, pose particular problems (Zhao et al. A criticism of this method has been that measurements were only made during a short period during which food was given at regular hourly intervals. A later modification of this approach was to infuse the labeled amino acid during a period of fasting followed by a period of hourly meals, thus acknowledging the discontinuous way in which food is normally taken (Young et al. However, although this was an advance on the earlier approach, assumptions still had to be made to extrapolate the results from the short periods to a full day. Thus the 24-hour amino acid balance method was developed to determine the balance of the test amino acid over a 24-hour period that encompassed periods of fasting and feeding. This marked a significant advance in deter- mining amino acid requirements because it moved investigations away from the simple study of nitrogen metabolism and allowed, in principle at least, direct measurements of the quantities of the amino acid lost under different nutritional circumstances. The first limitation arises from the unresolved questions related to the method’s theoretical basis. This is difficult because amino acid metabolism is compartmentalized and measurements of plasma amino acid labeling likely underestimate true turnover, and hence true oxidative loss, of the amino acid. Although for some amino acids this problem can be circumvented by administering a labeled metabolic product of the amino acid (e. The second drawback is practical—measuring the oxidation of the test amino acid over a complete 24-hour period makes the method labor intensive. This probably underlies the fact that to date this method has been applied to only three amino acids: leucine (El-Khoury et al. The reasoning is that when a single indispensable amino acid is provided below its requirement, it acts as the single and primary limitation to the ability to retain other nonlimiting amino acids in body protein. These other amino acids, including the indicator amino acid, are then in nutritional excess and are oxidized (Zello et al. As the intake of the test amino acid is increased, protein retention increases and the oxidation of the indicator amino acid falls until the requirement level of the test amino acid is reached, after which the oxidation of the indicator amino acid is lower and essentially constant. The data are then analyzed to obtain as estimate of the intersection of the constant and linear portions of the relationship (the breakpoint). The first advantage is that the metabolic restrictions of carbon dioxide release apply only to the indicator amino acid. Second, the pool size of the indicator amino acid does not change radically as the intake of the test amino acid is varied. Thus to some extent, potential problems of compart- mentation are minimized and, in principle, the method does not require estimates of the turnover of the indicator amino acid. Second, the dependence of the result on the amount of total protein given during the isotope infusion has not been established. Third, the choice of the best indicator is still under study so that data obtained with the method are dependent on the assumption of the general applica- bility of the indicator amino acids (phenylalanine and lysine) that have been used most frequently. Classical nitrogen balance studies in humans show that it takes 7 to 10 days for urinary nitrogen to equilibrate in adults put on a protein-free diet (Rand et al. On the other hand, it has been shown that most (about 90 percent) of the adaptation in leucine kinetics is complete in 24 hours (Motil et al. These investigators were unable to show any effect of prior adaptation to these two different phenylalanine intakes on the rates of phenylalanine oxidation at changing phenylalanine intakes, where the adaptation to the test level was about 4 hours. Clearly, from this study, adaptations in amino acid metabolism appear to take place much more quickly than do adaptations in urinary nitrogen excretion and are (at least for leucine [Motil et al. For the regression models to work, ranges of intake (particularly at the low end) have to be fed. In practical terms, this has greatly hampered studies in infants, children, and other vulnerable groups. On the other hand, if the individual only needs to be on a low or even zero intake of the test amino acid for a matter of 8 hours, then it becomes feasible to study indispensable amino acids in these and other vulnerable groups.