By F. Shakyor. Lake Erie College. 2018.
An action potential as a function of time at one point on the axon is shown in Fig order alendronate 35mg. A negative implies that the voltage is added out of phase with the external input voltage purchase alendronate 35 mg with mastercard. This type of analysis has the advantage that we can learn about the sys- tem without a detailed knowledge of the individual system components order 35 mg alendronate visa. We can vary the frequency, the magnitude, and the duration of the input voltage and measure the corresponding output voltage. From these measurements, we can obtain some information about the ampliﬁer and the feedback compo- nent without knowing anything about the transistors, resistors, capacitors, and other components that make up the device. We could, of course, obtain this information and much more by a detailed analysis of the device in terms of its basic components, but this would involve much more work. In the study of complex biological functions, the systems approach is often very useful because the details of the various component processes are unknown. For example, in the iris control system, very little is known about the processing of the visual signals, the mechanism of comparing these signals to the reference, or the nature of the reference itself. Yet by shining light at various intensities, wavelengths, and durations into the eye and by measuring the corresponding changes in the iris opening, we can obtain signiﬁcant infor- mation about the system as a whole and even about the various subunits. Here the techniques developed by the engineers are useful in analyzing the sys- tem (see Exercises 14-3 and 14-4). However, many biological systems are so complicated with many inputs, outputs, and feedbacks that even the simpliﬁed systems approach cannot yield a tractable formulation. A few years later, Kuhne ﬁxed the retina from the head of a guillotined crim- inal. He observed an image, but he could not interpret it in terms of anything that the man had seen before he was beheaded. As we will describe later, the eye goes far beyond the camera in processing the images that are projected on the retina. The iris is the optical aperture of the eye, and its size varies in accordance with the available light. If there is adequate light, the quality of the image is best with the smallest possible aperture. A small aperture restricts the light path to the center of the lens and eliminates the distortions and aberrations produced by the periphery. A smaller aperture also improves the image quality of objects that are not located at the point on which the eye or the camera is focused. An image is in sharp focus at the retina (or ﬁlm) only for objects at a speciﬁc dis- tance from the lens system. The electron orbits about the nucleus and can occupy only discrete orbits with radii 1, 2, 3, and so on. The Bohr model was very successful in explaining many of the experimen- tal observations for the simple hydrogen atom. But to describe the behavior of atoms with more than one electron, it was necessary to impose an additional restriction on the structure of the atom: The number of electrons in a given orbit cannot be greater than 22, where is the order of the orbit from the nucleus. Thus, the maximum number of electrons in the ﬁrst allowed orbit is 2 (1)2 2; in the second allowed orbit, it is 2 (2)2 8; in the third orbit, it is 2 (3)2 18, and so on. Lithium has three electrons, two of which ﬁll the ﬁrst orbit; the third electron, there- fore, must be in the second orbit. This simple sequence is not completely applicable to the very complex atoms, but basically this is the way the ele- ments are constructed. A speciﬁc amount of energy is associated with each allowed orbital con- ﬁguration of the electron. Therefore, instead of speaking of the electron as being in a certain orbit, we can refer to it as having a corresponding amount of energy. The electrons in the atom can occupy only speciﬁc energy states; that is, in a given atom the elec- tron can have an energy 1, 2, 3, and so on, but cannot have an energy between these two values. This is a direct consequence of the restrictions on the allowed electron orbital conﬁgurations. The lens equations we have presented in this appendix assume that the lenses are thin. By promoting the right “dosage” of physical activity, you are prescribing a highly effective “drug” to your patients for the prevention, treatment, and management of more than 40 of the most common chronic health conditions encountered in primary practice. This Guide acknowledges and respects that today’s modern healthcare provider may have only a brief window of time for physical activity counseling (at times no more than 20-30 seconds) during a normal office visit. Write a prescription for physical activity, depending on the health, fitness level, and preferences of your patients, and 3. Refer your patients to certified exercise professionals, who specialize in physical activity counseling and will oversee your patients’ exercise program. The Physical Activity Assessment, Prescription and Referral Process documents are the core of the guide and will explain how you can quickly assess physical activity levels, provide exercise prescriptions, and refer patients to certified exercise professionals. Print out and display copies of the Office Flyers in your waiting room and throughout your clinic. Regularly assess and record the physical activity levels of your patients at every clinic visit using the Physical Activity Vital Sign.
Patient Response: Mistrust and Refusal As noted above alendronate 70mg amex, the responses of racial and ethnic minority patients to healthcare providers are also a potential source of disparities cheap alendronate 35mg amex. Little research has been conducted as to how patients may influence the clinical encounter buy 70mg alendronate with visa. It is reasonable to speculate, how- ever, that if patients convey mistrust, refuse treatment, or comply poorly with treatment, providers may become less engaged in the treatment process, and patients are less likely to be provided with more vigorous treatments and services. But these kinds of reactions from minority patients may be understandable as a response to negative racial experi- ences in other contexts, or to real or perceived mistreatment by providers. Survey re- Little research has search, for example, indicates that minority patients perceive higher levels of racial dis- been conducted as to crimination in healthcare than non-minorities. Patients’ and providers’ behavior and atti- how patients may in- tudes may therefore influence each other reciprocally, but reflect the attitudes, expecta- fluence the clinical en- tions, and perceptions that each has developed in a context where race and ethnicity are counter. Given that stereotypes, bias, and clinical uncertainty may influence clinicians’ diag- nostic and treatment decisions, education may be one of the most important tools as part of an overall strategy to eliminate healthcare disparities. Healthcare providers should be made aware of racial and ethnic disparities in healthcare, and the fact that these dispari- ties exist, often despite providers’ best intentions. In addition, all current and future healthcare providers can benefit from cross-cultural education. Cross-cultural education programs have been developed to enhance health professionals’ awareness of how cul- tural and social factors influence healthcare, while providing methods to obtain, negotiate and manage this information clinically once it is obtained. Cross-cultural education can be divided into three conceptual approaches focusing on attitudes (cultural sensitiv- ity/awareness approach), knowledge (multicultural/categorical approach), and skills (cross-cultural approach), and has been taught using a variety of interactive and experien- 5 tial methodologies. Research to date demonstrates that training is effective in improving provider knowledge of cultural and behavioral aspects of healthcare and building effec- Healthcare providers tive communication strategies. Data on patient and provider race and care, and the fact that ethnicity would allow researchers to better disentangle factors that are associated with these disparities exist, healthcare disparities, help health plans to monitor performance, ensure accountability to often despite provid- enrolled members and payors, improve patient choice, allow for evaluation of interven- ers’ best intentions. Unfortunately, standardized data on racial and ethnic differences in care are generally unavailable, and a number of ethical, logistical, and fiscal concerns present challenges to data collection and monitor- ing, including the need to protect patient privacy, the costs of data collection, and resis- tance from healthcare providers, institutions, plans and patients. In addition, health plans have raised significant concerns about how such data will be analyzed and reported. The challenges to data collection should be addressed, as the costs of failing to assess racial and ethnic disparities in care may outweigh new burdens imposed by data collection and analysis efforts. Many other strategies must be undertaken, in conjunction with the training and edu- cational strategies described here, to eliminate racial and ethnic disparities in healthcare. As noted in the report, these include, for example, policy and regulatory strategies that address fragmentation of health plans along socioeconomic lines, and health systems in- terventions to promote the use of clinical practice guidelines and promote the use of in- terpretation services where community need exists. In short, a comprehensive, multi-level strategy is needed to eliminate these disparities. Broad sectors – including healthcare providers, their patients, payors, health plan purchasers, and society at large – must work Many other strategies together to ensure all patients receive a high quality of healthcare. The following is only a partial list of some of these resources, and is not intended as an endorsement of the products or disparities in health- individuals and groups that produced them: care. Cultural Competence: Essential Measure- ments of Quality for Managed Care Organizations. Kaiser Family Foundation and the Robert Wood Johnson Foundation have recently joined forces to sponsor an initiative to increase dialogue among physicians regarding healthcare disparities. Conscious and nonconscious African American stereotypes: Impact on first impression and diagnostic ratings by therapists. The ef- fect of race and sex on physicians’ recommendations for cardiac catherization. The effect of patient race and socio-economic status on physi- cian’s perceptions of patients. The views presented in this report are those of the Institute of Medicine Committee on Understanding and Eliminating Racial and Ethnic Disparities in Health Care and are not necessarily those of the funding agencies. The Institute of Medicine is a private, nonprofit organization that provides health policy advice under a congressional charter granted to the National Academy of Sciences. Cosmetics can have a psychological and social impact that cannot be underestimated. I want to thank all the contributors for participating in this project and particularly the editors, Perry Romanowski and Randy Schueller, for conceiving, organizing, and coordinating this book. It is the second book that they have contributed to this series and we appreciate their efforts. Special thanks are due to Sandra Beberman and Erin Nihill of the editorial and production staff at Marcel Dekker, Inc. Finally, I would like to thank my wife, Eva, without whose constant support and editorial help I would not have undertaken this project. Sunscreens: Development, Evaluation, and Regulatory Aspects, edited by Nicholas J.
Those acting on the end-plate nicotinic receptors (N ) are tubocurarine generic 70 mg alendronate fast delivery, atracurium safe 70 mg alendronate, and succinylcholine order alendronate 35mg with amex. Those acting on muscarinic (M) receptors M include atropine, benztropine, and scopolamine. All M-receptor activators are nonspecific (they act on Ml-3), and, in general, M-receptor activation decreases cardiovascular function and increase secretions and smooth muscle contraction. Table 11- 2-1 summarizes the type of M receptor involved and the specific end-organ responses to M-receptor activators. Table 11-2-2summarizes the effects of nicotinic receptor activation on the adrenal medulla, the autonomic ganglia, and the neuromuscular junction. The effect of autonomic ganglia stimulation depends upon the transmission system used to connect the ganglia to the end organ. Table 11-2-3summarizes the receptor mechanisms used by the various receptor types. Table 11-2-4summarizes the activity, properties, and clinical uses for the direct-acting cholinomimetics, and Table 11-2-5 does the same for the indirect-acting ones. Although these are less toxic for humans, they still provide a hazard, causing poisoning with both acute and chronic symptoms caused by both muscarinic and nicotinic hyperactivity ("dumbbelss"). In simple terms, increasing doses of atropine progressively decreases secretions and causes mydriasis, blurred vision, tachycardia, constipation, and urinary retention. Overdoses of over-the-counter medications containing M blockers are common causes of toxicity. Management is largely symptomatic, although physostigmine may be useful because it helps counteract both central and peripheral effects. The clinical uses and properties of the M-blocking drugs are summarized in Table 11-2-6. Table 11-2-7summarizes specific effects of ganglionic blocking agents and the transmission system employed for various specific organs. Drugs and uses: donidine and methyldopa (mild to moderate hypertension) • See Cardiovascular section. Effect of High-dose Epinephrine Is Similar to Norepinephrine Dose-dependent effects: - Low-dose. Table 11-3-1summarizes the distribution and physiologic effects associated with the activation of alpha 1 and 2, beta 1 and 2, and D] receptors. The cardiovascular effects of epinephrine (E) are betalike at low doses and alphalike at high doses. The properties, clinical uses, and adverse effects of the nonselective beta receptor antagonist propranolol are described. A comparison of beta adrenoceptor antagonists that are cardioselective and those that have intrinsic sympathomimetic activity is made (Table 11-3-3). Emergency drug management prior to surgery usually involves cholinomimetics, carbonic anhydrase inhibitors, and/or mannitol. Note Drug Drug Class Mechanism of Action Antimuscarinic drugs and Pilocarpine, Cholinomimetic Activation of M receptors causes contraction echothiophate of ciliary muscle, which increases flow (;(1 agonists are contraindicated through the canal of Schlemm; echothiophate in closed-angle glaucoma. Figure 11-4-8 Arterial contraction Heart rate t t Time 1 2 3 4 5 Given the following information: o Contractile force is measured in an isolated arterial preparation, and heart rate is measured in an isolated heart preparation. The effects of autonomic drugs affecting the cardiovascular system are summarized visually in Figures 11-4-2through 11-4-11. Which one of the following effects is not caused by the ingestion of mushrooms that contain pilocarpine? An increase in the cytosolic concentration of norepinephrine in sympathetic nerve end- ings leads to A. A 5-year-old child becomes ill while visiting relatives who have a farm in Arkansas. His symptoms include severe abdominal cramps with vomiting and diarrhea and profuse lacrimation and salivation. If these symptoms are due to chemical toxicity, the most likely cause is exposure to A. The activation of muscarinic receptors in bronchiolar smooth muscle is associated with A. Overuse of certain decongestants that are indirect-acting sympathomimetics can lead to a diminished response. With this principle in mind, one can anticipate that hexa- methonium will cause A. The presumptive diagnosis was drug toxicity due to the ingestion of a compound similar to A. Reflex tachycardia is most likely to occur after the systemic administration of A. Which one of the following sites is characterized by adrenergic neurohumoral transmis- sion? Activation of prejunctional 0:2 receptors on sympathetic nerve endings is associated with A. The data in the table below show the effects of four drugs (#1-4) on mean blood pressure administered as individual agents before and after treatment with prazosin.
The effects of various drugsondeﬁbrillation energy requirements are summarized in Table 9 generic 35 mg alendronate. In thisﬁnal sec- tion generic alendronate 70 mg online, that informationisapplied to the use of antiarrhythmic drugs in the treatmentofspeciﬁccardiac arrhythmias buy alendronate 70mg mastercard. Chapter 10 reviews some basic principles that should be kept in mind whenusing an- tiarrhythmic drugs. On the basisofthegenerally limited efﬁcacyofantiarrhythmic drugsaswell as their inherent propensity to cause serious problems, the ﬁrst principle should be completely self-evident;namely, one should avoid using antiarrhythmic drugs whenever possible. Thus, when one has decided to prescribe an antiarrhythmic drug, the ﬁnal step before actually writing the order should be to ask, “Does this patient really need this drug? Before prescribing an antiarrhythmic drug, the physician should be certain that the arrhythmia meets one of these two conditions. The second basic principle istokeep the goal of treatment clearly in mind and to tailor the aggressiveness of one’s therapyaccordingly. If one is treating an arrhythmiatoprevent death or permanent in- jury, for instance, a relatively aggressive approach may be appropri- ate and necessary. In theory, if the object istospare life and limb, one should err on the side of efﬁcacy, perhaps willingly accepting the risk of certain drug toxicities. Inpractice, however, as we will see in Chapters 11 and 12, there are relatively fewinstances today where oneought to rely primarily on antiarrhythmic drugs to treat arrhythmias that threaten life and limb. In these cases, one generally shoulduse a stepwise strategy, beginning with milder, less risky forms of treatment, and carefully reassessing the risk-to-beneﬁt ratio before each potential escalation of therapy. All too oftenphysicians pursue the treatment of relatively insigniﬁcant arrhythmias with Ninja-like intensity, an error that can result in unnecessary injury or death. The ﬁnal basic principle of using antiarrhythmic drugs is that, if one feels compelled to expose a patient to the risk of the drugs, one should also feel compelled to take every reasonable precaution to reduce the risks. For instance, given the almost universal risk of proarrhythmia, one should oftenconsider placing patients on a cardiacmonitor while antiarrhythmic drugs are being initiated be- cause, although proarrhythmia can occuranytime during the course of treatment, a signiﬁcant proportion of these events occur during the ﬁrst 3 or 4days of drug usage. The accompanying tables summarize the factors that should be consideredinchoosing antiarrhythmic drugs for patients with and withoutsigniﬁcant underlying cardiacdisease. Pro- cainamide, for instance, shouldnot be usedinpatients with systemic lupus erythematosus; quinidine shouldnot be usedinpatients with chronic colitis;patients with severe lung disease (in whommild drug-inducedpulmonary toxicity goes a long way) ideally shouldnot receive amiodarone;patients with a history of heart failure should not receive drugs with negative inotropic effects. Beyond these obvious individual considerations, the presenceor absenceofunderlying heart disease is the most important variable in choosing an antiarrhythmic drug,because heart disease predisposes patients to reentrant circuits and, therefore, to proarrhythmia. Amiodarone rises in rank because of its relatively low risk of producing proarrhythmia. Sotalol and dofetilide carry a moderate risk of torsades de pointes for all patients. Amiodarone carries a substantial risk of signiﬁcantend-organ toxicity for all patients, thoughonly a rela- tively small risk of proarrhythmia. The drug of choice in treating both atrial and ventricular tach- yarrhythmias dependson the presence or absenceofunderlying cardiacdisease. For ventricular arrhythmias, the primary con- siderationinpatients without underlying heart disease (i. As soon as one moves beyond these two classes of drugs, onebeginsaccepting asubstantial risk of proarrhythmia or other signiﬁcant toxicity. On the other hand, for patients with underlying heart disease who require therapy for ven- tricular arrhythmias, efﬁcacy(which here includes avoiding proar- rhythmia) is often the primary consideration. Thus, amiodarone is often the ﬁrst drug considereddespite its potential for causing long-term end-organ toxicity. To summarize, whenit comes to using antiarrhythmic drugs, there are no pretty choices. If this is not possible, one must proceedwith the goals of treatment clearly in mind and take every precaution to avoid producing more problems than are caused by the arrhythmias being treated. Such maneuvers include Valsalva, carotid massage, ocular massage, and dunking one’s face in ice water. Antitachycardia pacing techniques are also highly effective in termi- nating supraventricular arrhythmias, butsincesomany less invasive options are available, pacing is rarely usedunless an atrial pacemaker is already in place. Prior to the 1990s, pharmacologic therapy was the only viable option for most patients. Given that choice, many patients quite reasonably opted for no therapy at all and accepted the fact that they would have to make periodic pilgrimages to emergency rooms to terminate acute episodes. With thistechnique, critical components of the reentrant path- ways responsible for a patient’s arrhythmia can be mappedinthe electrophysiology catheterization laboratory and cauterized (usually with radiofrequencyenergy) directly through the electrophysiology catheter. Therefore, treatmentaimed at maintain- ing sinus rhythmis inherently difﬁcult and relatively risky. Often, it is more appropriate to accepta“lesser” therapeutic goal—that is, to allow the underlying arrhythmiatopersist while controlling the ventricular rate.
Systemic adrenocorticosteroids are sometimes indicated to treat dermatologic diseases and there is a small collection of these agents (Box 13 buy alendronate 70mg with amex. The frequency of con- genital anomalies was not increased among 43 infants born to women who took pred- nisone during early pregnancy (Heinonen et al purchase alendronate 70mg otc. Perinatal deaths were increased in frequency among infants born to women who took this steroid throughout preg- nancy discount alendronate 35mg with visa, but the disease being treated (e. Fetal growth retardation was associated with prednisone use during gestation by one research group (Reinisch et al. Prednisone and prednisolone Prednisone and prednisolone are active adrenoglucocorticoids. Numerous animal studies reported an increase in the fre- quency of cleft palate with prednisolone (as well as other steroids) when given in large doses (e. The association between oral clefts and prednisone exposure was assessed among humans using data from well-regarded case–control studies (Carmichael and Shaw, 1999; Rodriguez-Pinilla and Martinez-Frias, 1998) and it was concluded that the risk of nonsyndromic cleft palate may be associated with prednisone/prednisolone and other glucocorticoid exposure during embryogenesis. Note that most oral clefts can be surgically corrected and this isolated defect is not associated with other physical or mental abnor- malities. Hydrocortisone Hydrocortisone, another glucocorticoid, is the main steroid produced by the adrenal glands. The frequency of congenital anomalies was not increased among infants whose mothers took hydrocortisone during early pregnancy, including the first trimester (Heinonen et al. As with prednisone/prednisolone, an increased frequency of cleft palate was found among the offspring of experimental animals whose mothers were given hydrocortisone during embryogenesis (Chaudhry and Shah, 1973; Harris et al. It is possible that a small risk for cleft palate in humans exists with hydrocortisone use during embryogenesis, but it is likely that the risk is small at less than 1 percent (Shepard et al. Adrenocorticosteroids 247 Dexamethasone and betamethasone These agents (dexamethasone and betamethasone) are glucocorticoids that are closely related to prednisone (see Prednisone and prednisolone above). No human teratology studies of dexamethasone or betamethasone have been published. These drugs are com- monly used in the late second and early third trimesters to promote fetal lung maturity, preventing respiratory distress syndrome (Collaborative Group on Antenatal Steroid Therapy, 1984; Liggins, 1976; Liggins and Howie, 1974). Consistent with other corti- costeroids, dexamethasone and betamethasone are reported to be associated with an increased frequency of cleft palate in the offspring of pregnant animals that received these agents during embryogenesis (Mosier et al. Fetal body and organ weight were decreased in several animal studies with exposure to these glucocorticoids during pregnancy (Barrada et al. As with other glucocorticoids, it is possible that a small risk for cleft palate in humans exists with dexamethasone and betametha- sone use during early pregnancy. Triamcinolone No human epidemiological studies of triamcinolone use during early pregnancy have been published. The published case–control studies are confounded and it is not possi- ble to interpret them for triamcinolone exposures. The cause of concern for triamci- nolone exposure during embryogenesis is an increased frequency of congenital anom- alies found in offspring of three species of nonhuman primates that received this corti- costeroid during embryogenesis (Bacher and Michejda, 1988; Hendrickx and Tarara, 1990; Hendrickx et al. The collection of congenital anomalies included neural tube defects, craniofacial malformations, and skeletal anomalies. Therefore, triamcinolone should be avoided dur- ing pregnancy, especially during the first trimester (Friedman and Polifka, 2006). Triamcinolone will most probably be associated with an increased risk of birth defects in humans when these studies are reported. This warning is issued to attempt a reduc- tion of the number of infants who will be damaged, i. Cortisone The risk of congenital anomalies among women who used cortisone during pregnancy and its possible adverse fetal effects cannot be assessed with the available published data. Among only 34 infants exposed to cortisone during early pregnancy, the frequency of congenital anomalies was not increased (Heinonen et al. Cortisone is in the drug class (glucocorticoids) noted above to be associated with an increased frequency of cleft palate in several animal models, including nonhuman primates (Biddle and Fraser, 1976; Walker, 1971). The nonhuman primate association, even with small sample sizes, is an ominous indicator. Based mostly on primate data, these agents will predictably be shown to be associated with an increased frequency of isolated cleft palate in human 248 Use of dermatologics during pregnancy infants exposed to glucocorticoids during embryogenesis. Glucocorticoids summary In summary, limited human data are published of adrenocorticosteroid use during early human pregnancy and possible association with congenital anomalies or other possible adverse fetal effects. Although these agents were used for many years in pregnant women without apparent adverse effects, no systematic studies are available. Recent analyses based upon reputable case–control studies indicate that a low risk (< 1 percent) for cleft palate may be associated with glucocorticoid exposure during the first trimester. Triamcinolone effects are possibly more severe, suggesting that it would be prudent to avoid this drug during pregnancy – especially during early gestation. However, the con- sequence of not treating certain conditions during pregnancy, such as systemic lupus ery- thematosus and asthma, generally outweigh any theoretical risk of these medications. Failure to treat lupus and asthma during pregnancy may result in congenital heart block or maternal death, respectively.