By K. Akrabor. Queens College.
In human muscle order kamagra 50mg free shipping, glutamine has an exceptionally large free pool cheap kamagra 50 mg without prescription, containing about 10 to 15 g of nitrogen purchase 50mg kamagra. After trauma kamagra 50mg visa, this pool can become depleted by more than 50 percent (Labow and Souba order kamagra 50 mg with amex, 2000); its loss may then make a significant contribution to the total loss of nitrogen. Although the plasma compartment is most easily sampled, the concen- tration of most amino acids is higher in tissue intracellular pools. Typically, large neutral amino acids, such as leucine and phenylalanine, are essen- tially in equilibrium with the plasma. Others, notably glutamine, glutamic acid, and glycine, are 10- to 50-fold more concentrated in the intracellular pool. Dietary variations or pathological conditions can result in substantial changes in the concentrations of the individual free amino acids in both the plasma and tissue pools (Furst, 1989; Waterlow et al. Pathways of Amino Acid Metabolism The exchange between body protein and the free amino acid pool is illustrated by the highly simplified scheme shown in Figure 10-2. Similarly, there is a second pool, consisting of the free amino acids dis- solved in body fluids. The arrows into and out of the protein pool show the continual degradation and resynthesis of these macromolecules (i. The other major pathways that involve the free amino acid pool are the supply of amino acids by the gut from the absorbed amino acids derived from dietary proteins, the de novo synthesis in cells (includ- ing those of the gut, which are a source of dispensable amino acids), and the loss of amino acids by oxidation, excretion, or conversion to other metabolites. Amino Acid Utilization for Growth Dietary protein is not only needed for maintaining protein turnover and the synthesis of physiologically important products of amino acid metabolism but is, of course, laid down as new tissue. Studies in animals show that the composition of amino acids needed for growth is very simi- lar to the composition of body protein (Dewey et al. It is important to note, however, that the amino acid composition of human milk is not the same as that of body protein (Dewey et al. Maintenance Protein Needs Even when mammals consume no protein, nitrogen continues to be lost. Provided that the energy intake is adequate, these “basal” losses are closely related to body weight and basal metabolic rate (Castaneda et al. In man, normal growth is very slow and the dietary requirement to support growth is small in relation to maintenance needs except at very young ages. It follows that maintenance needs are of particular impor- tance to humans and account for a very large majority of lifetime needs for dietary protein. It has been known for decades (Said and Hegsted, 1970) that the body’s capacity to conserve individual amino acids at low intakes varies, so the pattern of amino acids needed in the diet to match their individual catabolic rates does not correspond precisely with the composition of body protein. This implies that there is very effective recycling of indispensable amino acids released continuously from protein degradation back into protein synthesis. Under conditions where the diet is devoid of protein, the efficiency of amino acid recycling is over 90 percent for both indis- pensable and dispensable amino acids (Neale and Waterlow, 1974). While highly efficient, some amino acids are recycled at different rates than others. Physiology of Absorption, Metabolism, and Excretion Protein Digestion and Absorption After ingestion, proteins are denatured by the acid in the stomach, where they are also cleaved into smaller peptides by the enzyme pepsin, which is activated by the increase in stomach acidity that occurs on feed- ing. The proteins and peptides then pass into the small intestine, where the peptide bonds are hydrolyzed by a variety of enzymes. These bond- specific enzymes originate in the pancreas and include trypsin, chymotrypsins, elastase, and carboxypeptidases. The resultant mixture of free amino acids and small peptides is then transported into the mucosal cells by a number of carrier systems for specific amino acids and for di- and tri-peptides, each specific for a limited range of peptide substrates. After intracellular hydrolysis of the absorbed peptides, the free amino acids are then secreted into the portal blood by other specific carrier systems in the mucosal cell or are further metabolized within the cell itself. Absorbed amino acids pass into the liver, where a portion of the amino acids are taken up and used; the remainder pass through into the systemic circulation and are utilized by the peripheral tissues. Thus, a significant portion (at least 50 percent) of fecal nitrogen losses represents the fixation by the colonic and cecal bacteria of nitrogenous substances (urea, ammonia, and protein secretions) that have been secreted into the intestinal lumen. Some authors have argued that the host-colon nitrogen cycle, by which nitrogenous compounds that diffuse into the gut are converted to ammonia by the microflora and are reabsorbed, is a regulated function and serves as a mechanism of nitrogen conservation (Jackson, 1989). The theoretical basis of this proposition has been partly confirmed by the recent demon- stration of the availability to the host of indispensable amino acids synthe- sized by intestinal microbes (Metges et al.
Physical exam skills: Students should be able to perform a physical exam to establish the diagnosis and severity of disease trusted kamagra 50mg, including: • Jaundice cheap kamagra 100 mg with amex. Differential diagnosis: Students should be able to generate a prioritized differential diagnosis recognizing specific history and physical exam findings that suggest a specific etiology of liver disease 50 mg kamagra with mastercard. Laboratory interpretation: Students should be able to recommend when to order diagnostic and laboratory tests and be able to interpret them order kamagra 100mg amex, both prior to and after initiating treatment based on the differential diagnosis 50 mg kamagra for sale, including consideration of test cost and performance characteristics as well as patient preferences. Communication skills: Students should be able to: • Communicate the diagnosis, treatment plan, and subsequent follow-up to the patient and his or her family. Basic and advanced procedural skills: Students should be able to: • Assist in performing a paracentesis after explaining the procedure to the patient. Management skills: Students should able to develop an appropriate evaluation and treatment plan for patients that includes: • The diagnostic evaluation of asymptomatic, isolated elevation of the transaminases and/or Alk Phos. Demonstrate commitment to using risk-benefit, cost-benefit, and evidence- based considerations in the selection of diagnostic and therapeutic interventions for liver disease. Recognize the importance of patient needs and preferences when selecting among diagnostic and therapeutic options for liver disease. Respond appropriately to patients who are nonadherent to treatment for liver disease. Appreciate the impact liver disease has on a patient’s quality of life, well- being, ability to work, and the family. Recognize the importance of and demonstrate a commitment to the utilization of other healthcare professionals in the diagnosis and treatment of liver disease. Discuss the public health role physicians play in the prevention of viral hepatitis. Most often the primary care provider is the first health care professional to see a depressed patient. Frequently, the initial presentation is associated with somatic complaints that bring the patient to the physician. Major depression is also a relatively common accompaniment to serious medical conditions. There is significant evidence that primary care physicians commonly fail to diagnose major depression. With relatively recent improvements in available treatment, it is even more important for internists to screen for major depression and to know the common presenting symptoms. The internist should also be familiar with available therapeutic options and be prepared to treat selected patients, including those who decline consultation with a mental health professional. The epidemiology of major depression in the general population and the impact of major illness on the prevalence of major depression (e. Common somatic complaints that accompany depressive disorders and the potential for the occurrence of these symptoms without obvious psychological symptoms (e. The distinguishing features of major depression with psychotic features, bipolar disorder, dementia, and delirium. The differential diagnosis of major depression, including: • Other psychiatric disorders. Indications and efficacy of the basic therapeutic options for major depression, including: • Psychotherapy (cognitive behavioral therapy or interpersonal psychotherapy). The side effects of the major classes of antidepressants and common interaction with other medications. History-taking skills: Students should be able to obtain, document, and present an age-appropriate medical history, that differentiates among etiologies of disease including: • Eliciting the symptoms of major depression. Physical exam skills: Students should be able to perform a physical exam to establish the diagnosis and severity of disease, including: • A complete neurologic examination. Differential diagnosis: Students should be able to generate a prioritized differential diagnosis recognizing specific history and physical exam findings that suggest a specific etiology for major depression (psychiatric and nonpsychiatric). Laboratory interpretation: Students should be able to recommend when to order diagnostic and laboratory tests and be able to interpret them, both prior to and after initiating treatment based on the differential diagnosis, including consideration of test cost and performance characteristics as well as patient preferences. Laboratory and diagnostic tests should include, when appropriate: • Blood and urine drug screening. Communication skills: Students should be able to: • Communicate the diagnosis, treatment plan, and subsequent follow-up to the patient and his or her family. Management skills: Students should able to develop an appropriate evaluation and treatment plan for patients that includes: • An appreciation of the fact that major depression is not generally a “diagnosis of exclusion” and that ruling out all other possible medical causes is typically not necessary. Recognize major depression as an important and potentially life-threatening disease.
It should be recognized that for several of these questions kamagra 100 mg line, certain infer- ences have been widespread for long periods of time cheap kamagra 100mg with visa; thus 50 mg kamagra free shipping, it may seem unnecessary to raise these uncertainties anew purchase 100 mg kamagra amex. When several sets of animal toxicology data are available generic kamagra 100 mg mastercard, for example, and data are not sufficient for identifying the set (i. In the absence of definitive empirical data applicable to a specific case, it is generally assumed that there will not be more than a tenfold variation in response among members of the human population. In the absence of absorption data, it is generally assumed that humans will absorb the chemi- cal at the same rate as the animal species used to model human risk. In the absence of complete understanding of biological mechanisms, it is gener- ally assumed that, except possibly for certain carcinogens, a threshold dose must be exceeded before toxicity is expressed. The use of defaults to fill knowledge and data gaps in risk assessment has the advantage of ensuring consistency in approach (the same defaults are used for each assessment) and minimizing or eliminating case-by-case manipulations of the conduct of risk assessment to meet predetermined risk management objectives. The major disadvantage of the use of defaults is the potential for displacement of scientific judgment by excessively rigid guidelines. The risk assessors’ obligation in such cases is to provide explicit justification for any such departure. The use of preselected defaults is not the only way to deal with model uncertainties. Another option is to allow risk assessors complete freedom to pursue whatever approaches they judge applicable in specific cases. Because many of the uncertainties cannot be resolved scientifically, case- by-case judgments without some guidance on how to deal with them will lead to difficulties in achieving scientific consensus, and the results of the assessment may not be credible. Another option for dealing with uncertainties is to allow risk assessors to develop a range of estimates based on application of both defaults and alternative inferences that, in specific cases, have some degree of scientific support. Indeed, appropriate analysis of uncertainties seems to require such a presentation of risk results. Although presenting a number of plausible risk estimates has the advantage that it would seem to more faith- fully reflect the true state of scientific understanding, there are no well- established criteria for using such complex results in risk management. The various approaches to dealing with uncertainties inherent in risk assessment are summarized in Table L-1. As can be seen in the nutrient chapters, specific default assumptions for assessing nutrient risks have not been recommended. Assessment of protein en- ergy needs of Indian adults using short-term nitrogen balance methodology. Protein-Energy Requirement Studies in Developing Countries: Results of International Research. Human protein requirements: Obligatory urinary and faecal nitrogen losses and the factorial estimation of protein needs of Nigerian male adults. Long-term evaluation of the adequacy of habitual diets to provide protein needs of adult Nigerian men. Nitrogen balance study in young Nigerian adult males using four levels of protein intake. Obligatory urinary and fecal nitrogen losses in young women, older men, and young men and the factorial estimation of adult human protein requirements. Nitrogen balance response of young male adults fed predicted requirement levels of a Mexican rural diet. Protein-Energy Requirement Studies in Developing Countries: Results of International Research. A study of the endogenous nitrogen output of college women, with particular reference to use of the creatinine output in the calcu- lation of the biological values of the protein of egg and of sunflower seed flower. 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. Comparative nitrogen balance study between young and aged adults using three levels of protein intake from a combination wheat-soy-milk mixture. Nitrogen balances of adult human subjects who consumed four levels of nitrogen from a combination of rice, milk and wheat. The protein requirements of Brazilian rural workers: Studies with a rice and bean diet.