By U. Aschnu. Walden University.
The enhanced use of fatty acids for en- Although a limited supply of glucose is available from ergy metabolism spares the blood glucose supply order penegra 100mg visa prostate one a day. There is glycogen stored in the liver effective penegra 100 mg prostate warmer, the more important source of also significant gluconeogenesis in liver from the glycerol blood glucose during the first days of a fast is gluconeoge- released from triglyceride by lipolysis buy discount penegra 50 mg on-line man health 180. In prolonged fast- nesis in the liver and, to some extent, in the kidneys. Amino acids derived from tissue protein are the main rived from triglyceride glycerol. Fasting results in protein breakdown in the Within a few hours of the start of a fast, the increased skeletal muscle and accelerated release of amino acids into delivery to and oxidation of fatty acids in the liver results in the bloodstream. Protein breakdown and protein accretion the production of the ketone bodies. As a result of these in adult humans are regulated by two opposing hormones, events in the liver, a gradual rise in ketone bodies occurs in insulin and glucocorticoids. During fasting, insulin secre- the blood as a fast continues over many days (Fig. As proteins are broken down, the CNS during the later stages of fasting. Two products acids released into the blood by the skeletal muscle are ex- resulting from the breakdown of fatty acids, acetyl CoA tracted from the blood at an accelerated rate by the liver and citrate, inhibit glycolysis. The amino acids then undergo metabolic use of glucose from the blood is reduced. The newly synthesized glucose is then delivered tion to fasting is to provide the body with glucose pro- to the bloodstream. From that point on, the in this process by maintaining gene expression and, there- body uses mainly fat for energy metabolism, and it can fore, the intracellular concentrations of many of the en- survive until the fat depots are exhausted. Glucocorticoids zymes needed to carry out gluconeogenesis in the liver and do not trigger the metabolic adaptations to fasting but kidneys. For example, glucocorticoids maintain the only provide the metabolic machinery necessary for the amounts of transaminases, pyruvate carboxylase, phospho- adaptations to occur. When present in excessive amounts, needed to carry out gluconeogenesis at an accelerated rate. Cushing’s disease is the name of amounts of these enzymes in the liver are greatly reduced. Cushing’s disease CHAPTER 34 The Adrenal Gland 619 may be ACTH-dependent or ACTH-independent. One plasma membrane phospholipids by the hydrolytic action type of ACTH-dependent syndrome (actually called Cush- of phospholipase A2. Glucocorticoids stimulate the syn- ing’s disease) is caused by a corticotroph adenoma, which thesis of a family of proteins called lipocortins in their tar- secretes excessive ACTH and stimulates the adrenal cortex get cells. Lipocortins inhibit the activity of phospholipase to produce large amounts of cortisol. ACTH-independent A2, reducing the amount of arachidonic acid available for Cushing’s syndrome is usually due toa result of an adreno- conversion to prostaglandins and leukotrienes. Whatever the cause, prolonged exposure of the body to Effects on the Immune System. Glucocorticoids have large amounts of glucocorticoids causes the breakdown of little influence on the human immune system under normal skeletal muscle protein, increased glucose production by physiological conditions. When administered in large the liver, and mobilization of lipid from the fat depots. De- doses over a prolonged period, however, they can suppress spite the increased mobilization of lipid, there is also an ab- antibody formation and interfere with cell-mediated immu- normal deposition of fat in the abdominal region, between nity. Glucocorticoid therapy, therefore, is used to suppress the shoulders, and in the face. The increased mobilization the rejection of surgically transplanted organs and tissues. The underutilization of glucose concentrations of glucocorticoids, decreasing the number by skeletal muscle, coupled with increased glucose produc- of circulating lymphocytes. The destruction of immature T tion by the liver, results in hyperglycemia, which, in turn, and B cells by glucocorticoids also causes some reduction in stimulates the pancreas to secrete insulin. Glucocorticoids are required for the normal responses of vas- Evidence also indicates that excessive glucocorticoids de- cular smooth muscle to the vasoconstrictor action of norep- crease the affinity of insulin receptors for insulin. NE is much less active on vascular smooth muscle result is that the individual becomes insensitive or resistant in the absence of glucocorticoids and is another example of to the action of insulin and little glucose is removed from the permissive action of glucocorticoids. The persisting hyperglycemia continually stimulates the pan- Glucocorticoids and Stress. The result is a form of “diabetes” ing, but least understood, of all glucocorticoid action is the similar to Type 2 diabetes mellitus (see Chapter 35). All that is really The opposite situation occurs in the glucocorticoid-de- known is that the body cannot cope successfully with even ficient individual. Little lipid mobilization and use occur, so mild stresses in the absence of glucocorticoids. One must there is little restriction on the rate of glucose use by tis- presume that the processes that enable the body to defend sues. The glucocorticoid-deficient individual is sensitive to itself against physical or emotional trauma require gluco- insulin in that a given concentration of blood insulin is corticoids. This, again, emphasizes the permissive role they more effective in clearing the blood of glucose than it is in play in physiological processes. The administration of even small doses of Stress stimulates the secretion of ACTH, which in- insulin to such individuals may produce hypoglycemia. In humans, this increase in glucocor- The Anti-inflammatory Action of Glucocorticoids. Tis- ticoid secretion during stress appears to be important for sue injury triggers a complex mechanism called inflamma- the appropriate defense mechanisms to be put into place. A is well known, for example, that glucocorticoid-deficient host of chemical mediators are released into the damaged individuals receiving replacement therapy require larger area by neighboring cells, adjacent vasculature, and phago- doses of glucocorticoid to maintain their well-being during cytic cells that migrate to the damaged site. These substances exert a multitude of actions at physiological action of glucocorticoids is the ability to reg- the site of injury and directly or indirectly promote the lo- ulate their own secretion. This effect is achieved by a neg- cal vasodilation, increased capillary permeability, and ative-feedback mechanism of glucocorticoids on the secre- edema formation that characterize the inflammatory re- tion of corticotropin-releasing hormone (CRH) and sponse (see Chapter 11). ACTH and on proopiomelanocortin (POMC) gene ex- Because glucocorticoids inhibit the inflammatory re- pression (see Chapter 32). Their regulation of the production of PRODUCTS OF THE ADRENAL MEDULLA prostaglandins and leukotrienes is the best understood. These substances play a major role in mediating the in- The catecholamines, epinephrine and norepinephrine, are flammatory reaction. They are synthesized from the unsat- the two hormones synthesized by the chromaffin cells of urated fatty acid arachidonic acid, which is released from the adrenal medulla.
Estrogen therapy is controversial at this time (results of the Women’s Health Initiative) 6 cheap penegra 50mg mens health six pack. Bisphosphonates are the drugs of choice aldendronate (daily or weekly) risedronate research studies: ✧ calcitonin ✧ parathyroid hormone CHAPTER 18: PRIMARY CARE NEEDS 93 8 discount penegra 100mg amex prostate quebec. Conclusion—preventing bone loss and vertebral fractures can be attained to some degree with any of the currently approved medications best 50mg penegra balance androgen hormones naturally, exercise, and possibly diet. A person who has sustained a fracture is certainly a candidate for pharmacologic therapy. Pulmonary dysfunction secondary to MS is a leading cause of morbidity and mortality in MS. Assessment should include history of pneumonia, aspiration, dypnea, weak cough, hypophonia, and fatigue. Treatment is predicated on noninvasive interventions whose goals are to: 1. Avoid upper respiratory infections, particularly during the influenza season ADDITIONAL READING Halper J. This page intentionally left blank Chapter 19 The Nurse’s Role in MS Research Objectives: Upon completion of this chapter, the learner will: Describe the roles and responsibilities of the nurse in MS research Identify key concepts in the research processResponsibilities of the research coordinator A. Investigator’s brochure—a detailed, confidential description of the structure and formulation of the drug, and a summary of the studies and adverse events. Source documents—documents that contain all the clinical information gathered during a visit. Case report forms—concise information reflective of the source documents entered into duplicate forms that are collected and returned to the sponsor for data entry. Open label—the investigators and patients are aware of what drug or treatment is being tested. Single-blinded study—the patient is blinded to the treatment but the investigator is aware of what is being tested. Double-blinded study—neither the investigator nor the patient knows who has been randomly assigned to what treatment (active therapy or placebo). Cross-over study—participants receive either placebo or tested therapy over a specific time, then investigational drug for the remainder of the study. Informed consent is obtained from the subjects or from a legal representative. The research plan makes adequate provision for monitoring the data to ensure the safety of subjects. The consent must be easily understood by a lay person and must contain the following: A. An explanation of the purpose of the research, the design or the study, and procedures that are experimental C. A description of any foreseeable risks or discomforts including, for women who are able to have children, risks to childbearing or to the fetus. A disclosure of appropriate alternative procedures or course of treatment, if any, that may be advantageous to the subject F. A statement describing the extent to which confidentiality of records will be maintained, including the fact that the FDA might inspect the records G. For research involving more than a minimal risk, an explanation as to whether compensation and medical treatments are available H. An explanation of who should be contacted for answers to pertinent questions about the research and the research subject’s rights I. A statement that participation is voluntary, refusal to partici- pate will not result in any penalty or loss of service to which the subject is otherwise entitled, and that the subject may withdraw at any time without penaltyAdverse events A. Adverse drug experience—any unfavorable and unintended sign, symptom, or disease temporally associated with the use of investigational product B. Serious adverse drug experience—any experience that results in death, a life-threatening adverse event, inpatient hospitalization 98 NURSING PRACTICE IN MULTIPLE SCLEROSIS: A CORE CURRICULUM or prolongation of hospitalization, a persistent or significant disability or incapacity related to the research C. Unexpected adverse drug experience—any adverse experience, the specificity or severity of which is not consistent with the current investigator’s brochureNursing assessment A. How realistic are the patient’s expectations of what the drug under study will and will not do for MS? Does the person understand that there might be a chance of receiving a placebo (in placebo-controlled studies)? Is the patient committed to the frequency of visits, testing requirements, and procedures outlined in the consent form and protocol? How successful has the patient been in the past in terms of keeping appointments and adhering to treatments? Does the patient lack adequate insurance for currently available treatments? Is the patient experiencing a decline in functional status despite aggressive therapeutic interventions? Keep in touch with other nurse coordinators for support and information. Participate in the investigators’ meeting; this is your opportunity to share experiences with others and with the sponsor. Think of research questions you may want to incorporate into the study; sponsors often are interested in other research questions. Chapter 20 Study Guide in Multiple Sclerosis Additional Readings The Canadian Multiple Sclerosis Nursing Care Plan. Using the transtheoretical model to facilitate behavior change in patients with chronic illness. Defining the course of multiple sclerosis: Results of an international survey. Evidence-based management strategies for urinary dysfunction in multiple sclerosis. Multiple Sclerosis: Key Issues in Nursing Management: Adherence, Cognitive Function, Quality of Life. Best Practices in Nursing Care: Disease Management, Pharmacological Treatment, Nursing Research. Chapter 21 Case Studies Case Study 1 Sally is thirty-four years old and was diagnosed with MS in 1992. She initially experienced a relapsing-remitting course in which her exac- erbations were mild and occurred infrequently. After her second preg- nancy, about 6 months postpartum, she had a severe exacerbation that resulted in paralysis of both lower extremities. Following hospitaliza- tion for intravenous steroids, she was treated in an inpatient rehabili- tation hospital for strengthening and improvement of function. When she was discharged, she was able to walk with a wheeled walker and she used a motorized tricart for longer distances. Her ability to walk has diminished, she is able to stand and pivot for transfers, and only take a few steps to and from chairs and her bed.
For the research community discount 50 mg penegra prostate cancer osteoblastic, it is also important to learn about the invasiveness and risks of the reference standard used cheap penegra 100mg online prostate gland enlargement. For example buy penegra 100mg mastercard prostate cancer proton therapy, if in the evaluation of the positive test results of Haemoccult screening colonoscopy, sigmoidoscopy or double contrast barium enema were to be used, one might expect complications (perforation or haemorrhage) once in 300–900 subjects investigated. To evaluate the relationship between a dichotomous test and the presence of a disorder, one can use the usual programs for sample size estimation. For example, for a case–referent study with equal group sizes, accepting certain values for type I and type II errors (for example 0. For the example above the calculation using the program EPI-Info29 would yield a required number of 27 cases and 27 referents. Of course, when performing a cross-sectional study prospectively in a consecutive series with a low 55 THE EVIDENCE BASE OF CLINICAL DIAGNOSIS expected prevalence of the target disorder (unequal group sizes), the required sample will be much higher. Also, if a number of determinants is simultaneously included in the analysis, the required sample size is higher: as a rule of thumb, for each determinant at least 10 subjects with the target disorder are needed. For single tests the first step is a Bivariate analysis focused on one predictive variable only, for example in a 2 2 table in the case of a dichotomous test. It is possible to stratify for modifiers of accuracy, thereby distinguishing relevant clinical subgroups, and to adjust for potential confounding variables. Point estimates and confidence intervals for the measures of diagnostic accuracy can be determined. Subsequently, there are various options for multivariable analysis, taking the influence of multiple independent variables into account simultaneously. Multiple logistic regression is especially useful for analysing accuracy data. It is important to distinguish the analytical approach focusing on the accuracy of individual tests from the analysis where an optimal prediction of the presence of the studied disorder in patients is at stake. In the first, the dependent variable may even be test accuracy itself, as a function of various determinants. In the latter, a diagnostic prediction model can be derived with disease probability as the dependent variable, and with various tests, demographic, and clinical covariables as independent variables. Further- more, using multivariate analysis such as multiple logistic regression, the combined predictive power of sets of test variables can be determined. Moreover, starting from the least invasive and most easily available test (such as history taking), it can be evaluated whether adding more invasive or more expensive tests contributes to the diagnosis. For example, the sub- sequent contributions of history, physical examination, laboratory testing, and more elaborate additional investigations can be analysed, supported by displaying the ROC curves (with areas under the curve) of the respectively extended test sets (see Chapter 7). The principal difference is that aetiologic analysis usually focuses on the effect of a hypothesised aetiologic factor adjusted for the influence of possible confounders, thereby aiming at a causal interpretation. In diagnostic research the focus is on identifying the best correlates of the target disorder irrespective of any causal interpretations. It is sufficient if these correlates (tests) can be systematically and reproducibly used for diagnostic prediction. Whereas in 56 ASSESSING THE ACCURACY OF DIAGNOSTIC TESTS aetiologic analysis there is a natural hierarchical relation between the possible aetiologic factor of interest and the covariables to be adjusted for, such a hierarchy is absent for the possible predictors in diagnostic research. This implies that diagnostic data analysis can be more pragmatic, seeking for the best correlates. External validation Analyses of diagnostic accuracy in the collected data set, especially the results of multivariable analyses, may produce too optimistic results that may not be reproducible in clinical practice or similar study populations. This approach is not addressing the issue of external validation: in fact, it only evaluates the degree of random error at the cost of possibly increasing such error by reducing the available sample size by 50%. An exploratory approximation, however, could be to compare the performance of the diagnostic model in the chronologically first enrolled half of the patients, with that in the second half. The justification is that the second half is not a random sample of the total, but rather a subsequent clinically similar study population. However, totally independent studies in other, clinically similar settings will be more convincing. In fact, over time, various studies can be done in comparable settings, enabling diagnostic systematic reviews and meta-analyses to be performed. This may yield a constantly increasing insight into the performance of the studied diagnostic test, both in general and in relevant clinical subgroups (Chapter 8). Multimorbidity in general practice: prevalence, incidence, and determinants of co-occurring chronic and recurrent diseases. Empirical evidence of design-related bias in studies of diagnostic tests. Limitations of sensitivity, specificity, likelihood ratio, and Bayes’s theorem in assessing diagnostic probabilities: a clinical example. Problems of spectrum and bias in evaluating the efficacy of diagnostic tests. The influence of referral patterns on the characteristics of diagnostic tests. Statistical and knowledge-based approaches to clinical decision support systems, with an application to gastroenterology. Application of logistic regression to the analysis of diagnostic data: exact modeling of a probability tree of multiple binary variables. Obstructive micturition problems in elderly males, prevalence and diagnosis in general practice. The effect of validation group bias on screening tests for coronary artery disease. The effects of disease verification and referral on the relationship between symptoms and diseases. Assessment of diagnostic tests when disease verification is subject to selection bias. Diagnostic value of the erythrocyte sedimentation rate in general practice. Screening for colorectal cancer using the faecal occult blood test,hemoccult. Multivariable prognostic models: issues in developing models, evaluating assumptions and adequacy, and measuring and reducing errors. The diagnostic value of scoring models for organic and non-organic gastrointestinal disease, including the irritable-bowel syndrome. Depending on the clinical problem under study, the type of information needed, and the costs of tests or follow up, one design can be preferred over another. For scientific purposes it is worth knowing whether or not a result from a medical test corresponds to the truth. These are the first questions that come to the mind in the evaluation of medical tests. From a patient perspective, mere knowledge about the present, true state of things is in most cases not enough.