By N. Gembak. Pacific Oaks College.
If possible penegra 100 mg lowest price, information centration of an agonist that produces 50% of the about differences in metabolism among species maximal possible response buy generic penegra pills. Kd is the equilibrium Elementary aspects constant for the two processes of drug–receptor combination and dissociation best 50mg penegra. Kd may be found The possibility that time since dose changes the for both agonists and antagonists buy penegra 50mg on-line, although some- relationship between pharmacological effect size times the former poses more technical challenge and drug concentrations in plasma has been known due to alterations to the conformation of the bind- for a long time (Levy, 1964, 1966; Levy and ing site. When an agonist must model may be expressed as: occupy 100% of available receptors to cause Emax, its efﬁcacy may be said to be unity. This model does not imal effect for an agonist with efﬁcacy 1 (we call contain any information about efﬁcacy and these partial agonists or agonist–antagonists). In the latter centration range, the relationship between effect case, the concentration–response curve lies to the and concentration is often observed to be curvi- left of the concentration–receptor occupancy linear. This log transformation of the concentration between observed concentration and effect size, axis facilitates a graphical estimation of the slope as examples from a considerable volume of litera- of the apparently linear segment of the curve: ture. The reader is referred to key texts for com- prehensive coverage of this topic (e. A more general form of the equation is the Levy (1964), Jusko (1971) and Smolen (1971, sigmoid curve: 1976) described the analysis of dose–response time data. Smolen Emax model, it is possible to account for curves (1976) extended the analysis to application which are both shallower and steeper than when of dose–response time data for bioequivalence n ¼ 1 (i. A half-life, bioavailability and potency can be very high exponent can be viewed as indicating an obtained simultaneously from the dose– all-or-none effect (e. Within a narrow con- assuming (a) ﬁrst-order input/output processes centration range, the observed effect goes from all and (b) extravascular dosing, the kinetic model to nothing or vice versa. An exponent less than then drives the inhibition function of the dynamic unity (<1) sometimes indicates active metabolites model. A zero-order The corresponding inhibitory sigmoid Emax input and ﬁrst-order output governs the turnover model is functionally described as follows: of the response. Many other types of examples each other (Segre, 1968; Wagner, 1968; Dahlstrom exist. The rate of The plasma kinetics of the analgesic were change of drug amount (Ae) in a hypothetical effect describable by the following expression after the compartment can be expressed as: intravenous bolus dose, with C0 ¼ 45:0 and À1 K ¼ 0:50 h : dAe ¼ kleA1 À ke0Ae dt À0:50t C ¼ 45:0e where A is the amount of drug in the central com- In the same study, effect measurements were partment of a pharmacokinetic model, linked to the recorded during 80 min, as shown in Figure 8. At steady state, Ce is directly proportional to the where K is the elimination rate constant. Note that the effect equilibration rate constant kleD ÀKt ke0t Ce ¼ ½e À e (ke0) may be viewed as a ﬁrst-order distribution rate Veðke0 À KÞ constant. It can also be thought of in terms of the rate of presentation of a drug to a speciﬁc tissue, At equilibrium, the rates of drug transfer between determined by, for example, tissue perfusion rate, the central and effect compartments are equal: apparent volume of the tissue and eventual diffu- sion into the tissue. The results of the data ﬁtting in k1eA ¼ ke0Ae this exercise with the analgesic are Emax 4. Effect compartment or link models are limited If the partition coefﬁcient, Kp, equals Ce/C at equi- by their applicability to situations in which the librium (steady state), then we can rearrange the equilibrium between plasma and response is due above equation: to distributional phenomena. In reality, there is k V often a delay between occurrence of maximum 1e 1 Ve ¼ drug concentration in the effect compartment and Kpke0 maximum intensity of effect caused by slow devel- Substituting for V in the above equation opment of the effect rather than slow distribution to e (i. The plasma kinetics of (S)-warfarin were described by the fol- This is how the link-model relates the kinetics in lowing mono-exponential expression: plasma to the kinetics of drug in the effect compart- ment. The time to steady state is only governed by 120 the elimination rate constant and not the rate of infusion. It was also possible to estimate As stated before, the intensity of a pharmacologi- the half-life of the apparent ﬁrst-order degradation. Rather, it may be the net allow for distributional effects embedded in the result of several processes only one of which is observed time delay of the onset of the effect inﬂuenced by the drug. The process that is inﬂu- after warfarin administration, was published by enced by the drug must be identiﬁed and an Pitsui et al. Setting the baseline value of attempt be made to relate plasma drug concentra- clotting factor activity in the absence of warfarin tion to changes in that process. Warfarin provides a (P0) to a ﬁxed mean of three predose measure- good example of this, as the anticoagulant (hypo- ments, the program can estimate that parameter. Precision increased of compounds emerging from medicinal chemistry when a ﬁnite lag time was included in the ﬁtting. These detract from their value in chemical, structure– two cases, however, are especially relevant to the activity analyses). Neither does any of these relationship between animal work and phase I studies approaches uses results of invitro functional assays in which only the simplest effects, such as counter- which emerge from screening of the compounds in action of a painful stimulus or raising/lowering of a biochemistry laboratories. This is a postgraduate textbook, and we wish to convey how in vitro and in vivo data In the future, models will exist which will link of various kinds may be used to help extrapolate constants for in vitro binding to cloned human observed drug effects from simple experimental receptors (Kd), data from in vitro functional assays systems to the more complex clinical situation. The ultimate need is to obtain useful predictions A composite prediction matrix will be applied of response in healthy human subjects (phase I rapidly and accurately to the process of synthesis studies) from observed drug effects in animals or of new compounds for phase I testing. In the shorter term, what can we now do to What are the strengths and weaknesses of these expedite the drug selection process? The use of intrinsic clearance in vitro represents a ﬂow chart illustrating one form of permits predictions between species for the parti- metabolism/pharmacokinetics input into the drug cular enzyme/route of metabolism concerned. Arrows (indicating the ﬂow of humans have qualitatively different routes of work and communication) pointing to the right metabolism for any particular compound, then represent perceived progress, whereas arrows point- this will weaken the predictive value of the in ing tothe leftrepresent ‘disappointments’ (and other vitro observation. The works best for compounds with a high component numbered asterisks indicate continuations. The of nonenzymatic elimination, such as our model ‘ﬂow of time’ is from left to right and from the top compound with approximately 90% excretion as panel to the bottom panel. This prediction weakens as var- tasks that are to be completed, and rectangles in a iations in rates of enzymatic reactions become column within a panel represent work done by more important. If preclinical work identiﬁed metabolite(s) to and may not necessarily be based on hard and fast measure in humans, are the pharmacokinetics criteria. Does the relationship between concentration compounds that have the same indication. For example, within the represents the tasks that can be expedited by online box including ‘in vitro intrinsic clearance’, there pharmacokinetic modeling. Among the pharmaco- may be in vitro predictors of oral availability and kinetic questions that will be asked online in the measures of potentially toxic metabolites. The ‘in phase I trial are the following: vivo pharmacokinetics’ in rats may include an increasing number of compartments whose con- 1. As the doses are escalated, do the kinetics of the centrations are measured by microdialysis and may drug appear to be linear or nonlinear over the include measures of a few selected metabolite dose range? However, it does show that the change in kinetics, for example a higher elim- chemists discover new chemical entities with ination rate that might be indicative of autoin- desirable properties. This is not a comprehensive ﬂow diagram for all aspects of drug discovery – it is restricted to the components of the process discussed in this chapter. In this context, phase I serves as the As a chemical series develops, correlations such interface between preclinical research and clinical as that in Figure 8. Eventually, a development, and the validity of the predictions compound or compounds is/are chosen for phase I from animals to humans involved is of paramount studies. In this scheme, phase I is inﬂuenced by pharma- We believe that with enhanced integrated study cokinetic and pharmacodynamic modeling. The objective is expe- lism and pharmacokinetics (Welling and Tse, ditious choice of the best compound, with the ever- 1995). The time saved could be used to permit a present limitations on information available. Note larger number of compounds with better pro- that this scheme can involve feedback from phase I spects, from a single research program, to be to renewed chemical synthesis, as well as choice of compared in phase I studies. Typically, after adequate preclinical char- acterization of a candidate drug and 14-day and/or 3-month multiple-dose toxicology studies in two References mammalian species, a very low dose is chosen for the ﬁrst human exposure to the drug. Doses may be single or short multiple- netics: the dynamics of drug absorption, distribution dose series. PharmacokineticandPha- a-adrenergic receptors and contraction of rat vas rmacodynamic Data Analysis: Concepts and Applica- deferens’. Interspecies scaling and comparisons Pharmacokinetic/Pharmacodynamic Analysis: in drug development and toxicokinetics. Financial pressures, even for the largest pharma- model ceutical companies, are generally much greater than in the past.
Considering that the full exercise of human rights and fundamental freedoms cheap 50 mg penegra free shipping, guaranteed by the European Convention on Human Rights and other national and international instruments order penegra overnight delivery, has as a necessary basis the existence of a peaceful society that enjoys the advantages of order and public safety; 394 Appendix 1 2 order line penegra. Considering that purchase penegra american express, in this respect, police play a vital role in all the member states, that they are frequently called on to intervene in conditions which are dangerous for their members, and that their duties are made yet more difficult if the rules of conduct of their members are not sufficiently precisely defined; 3. Being of the opinion that it is inappropriate for those who have committed vio- lations of human rights while members of police forces, or those who have belonged to any police force that has been disbanded on account of inhumane practices, to be employed as policemen; 4. Being of the opinion that the European system for the protection of human rights would be improved if there were generally accepted rules concerning the profes- sional ethics of the police that take account of the principles of human rights and fundamental freedoms; 5. Considering that it is desirable that police officers have the active moral and physical support of the community they are serving; 6. Considering that police officers should enjoy status and rights comparable to those of members of the civil service; 7. Believing that it may be desirable to lay down guidelines for the behavior of police officers in case of war and other emergency situations and in the event of occupation by a foreign power; 8. Adopts the following Declaration on the Police, which forms an integral part of this resolution; 9. Instructs its Committee on Parliamentary and Public Relations and its Legal Affairs Committee and the Secretary General of the Council of Europe to give maximum publicity to the declaration. A police officer shall fulfill the duties the law imposes upon him by protecting his fellow citizens and the community against violent, predatory, and other harm- ful acts, as defined by law. In particular, he shall refrain from and vigorously oppose all acts of corruption. Summary executions, torture, and other forms of inhuman or degrading treat- ment or punishment remain prohibited in all circumstances. A police officer is under an obligation to disobey or disregard any order or instruction involving such measures. A police officer shall carry out orders properly issued by his hierarchical supe- rior, but he shall refrain from carrying out any order he knows, or ought to know, is unlawful. If immediate or irreparable and serious harm should result from permitting the violation to take place he shall take immediate action, to the best of his ability. If no immediate or irreparable and serious harm is threatened, he must endeavor to avert the consequences of this violation, or its repetition, by reporting the mat- ter to his superiors. No criminal or disciplinary action shall be taken against a police officer who has refused to carry out an unlawful order. A police officer shall not cooperate in the tracing, arresting, guarding, or convey- ing of persons who, while not being suspected of having committed an illegal act, are searched for, detained, or prosecuted because of their race, religion or politi- cal belief. A police officer shall be personally liable for his own acts and for acts of com- mission or omission he has ordered and that are unlawful. It should always be possible to deter- mine which superior may be ultimately responsible for acts or omissions of a police officer. Legislation must provide for a system of legal guarantees and remedies against any damage resulting from police activities. In performing his duties, a police officer shall use all necessary determination to achieve an aim that is legally required or allowed, but he may never use more force than is reasonable. Police officers shall receive clear and precise instructions as to the manner and circumstances in which they should make use of arms. A police officer having the custody of a person needing medical attention shall secure such attention by medical personnel and, if necessary, take measures for the preservation of the life and health of this person. He shall follow the instruc- tions of doctors and other competent medical workers when they place a detainee under medical care. A police officer shall keep secret all matters of a confidential nature coming to his attention, unless the performance of duty or legal provisions require otherwise. A police officer who complies with the provisions of this declaration is entitled to the active moral and physical support of the community he is serving. Document 3 Declaration of Tokyo Guidelines for Medical Doctors concerning Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment in relation to Detention and Imprisonment. The utmost respect for human life is to be maintained even under threat, and no use made of any medical knowledge contrary to the laws of humanity. For the purpose of this Declaration, torture is defined as the deliberate, systematic, or wanton infliction of physical or mental suffering by one or more persons acting alone or on the orders of any authority to force another person to yield information, to make a confession, or for any other reason. Declaration The doctor shall not countenance, condone, or participate in the practice of torture or other forms of cruel, inhuman, or degrading procedures, what- ever the offence of which the victim of such procedure is suspected, accused, or guilty, and whatever the victim’s belief or motives, and in all situations, including armed conflict and civil strife. The doctor shall not provide any premises, instruments, substances, or knowledge to facilitate the practice of torture or other forms of cruel, inhu- man, or degrading treatment or to diminish the ability of the victim to resist such treatment. The doctor shall not be present during any procedure during which tor- ture or other forms of cruel, inhuman, or degrading treatment are used or threat- ened. A doctor must have complete clinical independence in deciding on the care of a person for whom he or she is medically responsible. The doctor’s fundamental role is to alleviate the distress of his or her fellow men, and no motive, whether personal, collective, or political, shall prevail against this higher purpose. Where a prisoner refuses nourishment and is considered by the doctor as capable of forming an unimpaired and rational judgment concerning the con- sequences of such voluntary refusal of nourishment, he or she shall not be fed artificially. The decision regarding the capacity of the prisoner to form such a judgment should be confirmed by at least one other independent doctor. The consequences of the refusal of nourishment shall be explained by the doctor to the prisoner. The World Medical Association will support and should encourage the international community the national medical associations and fellow doctors to support the doctor and his or her family in the face of threats or reprisals resulting from a refusal to condone the use of torture or other forms of cruel, inhuman, or degrading treatment. Principle 1 Health personnel, particularly physicians, charged with the medical care of prisoners and detainees have a duty to provide them with protection of their physical and mental health and treatment of disease of the same quality and standard as is afforded to those who are not imprisoned or detained. Principle 2 It is a gross contravention of medical ethics, as well as an offense under applicable international instruments, for health personnel, particularly physi- cians, to engage, actively, or passively, in acts that constitute participation in, complicity in, incitement to or attempts to commit torture or other cruel, inhu- man or degrading treatment or punishment. Principle 3 It is a contravention of medical ethics for health personnel, particularly physicians, to be involved in any professional relationship with prisoners or detainees the purpose of which is not solely to evaluate, protect or improve their physical and mental health. Principle 4 It is a contravention of medical ethics for health personnel, particularly physicians: a. To apply their knowledge and skills in order to assist in the interrogation of pris- oners and detainees in a manner that may adversely affect the physical or mental health or condition of such prisoners or detainees and which is not in accordance with the relevant international instruments; b. To certify or to participate in the certification of the fitness of prisoners or detainees for any form of treatment or punishment that may adversely affect their physical or mental health and which is not in accordance with the relevant international instruments or to participate in any way in the infliction of any such treatment or punishment that is not in accordance with the relevant inter- national instruments. Principle 6 There may be no derogation from the foregoing principles on any ground whatsoever, including public emergency. At the meeting of the Council of National Representatives of the Interna- tional Council of Nurses in Singapore in August 1975, a statement on the role of the nurse in the care of detainees and prisoners was adopted. The fundamental responsibility of the nurse is fourfold: to promote health, to prevent illness, to restore health, and to alleviate suffering. The nurse, when acting in a professional capacity, should at all times maintain standards of personal conduct that reflect credit on the profession. The nurse takes appropriate action to safeguard the individual when his or her care is endangered by a coworker or any other person. Members of the armed forces, prisoners and persons taking no active part in the hostilities a. The following acts are and shall remain prohibited at any time and in any place whatsoever with respect to the above-mentioned persons: a. Everyone is entitled to all the rights and freedoms, set forth in this Declara- tion, without distinction of any kind, such as race, color, sex, language, reli- gion, political or other opinion, national or social origin, property, birth or other status (Article 2), b. No one shall be subjected to torture or to cruel, inhuman, or degrading treat- ment or punishment (Article 5). In relation to detainees and prisoners of conscience, interrogation proce- dures are increasingly being employed resulting in ill effects, often perma- nent, on the person’s mental and physical health. Nurses having knowledge of physical or mental ill-treatment of detain- ees and prisoners must take appropriate action, including reporting the matter to appropriate national and/or international bodies. Nurses participate in clinical research carried out on prisoners only if the freely given consent of the patient has been secured after a complete explana- tion and understanding by the patient of the nature and risk of the research. The nurse’s first responsibility is to the patients, notwithstanding con- siderations of national security and interest. It will come into effect at some future date (unknown at the time of writing), and the Act will give effect to rights and freedoms guaranteed under the European Convention on Human Rights. No one shall be deprived of his life intentionally save in the execution of a sentence of a court following his conviction of a crime for which this penalty is provided by law. Deprivation of life shall not be regarded as inflicted in contravention of this article when it results from the use of force that is no more than absolutely necessary: a.
Low blood C levels of vitamin E have been linked to increased risk of cataracts and some research shows protective beneﬁts with supplements generic penegra 50mg otc. Consistent and long-term use of antioxidants order 50mg penegra overnight delivery, along with lifestyle changes purchase penegra 100 mg without prescription, are your best defence 100mg penegra for sale. In one study, people who took multivitamins or supplements containing vitamins C or E for more than 10 years had a 60 percent lower risk of devel- oping cataracts (Archives of Ophthalmology, 2000: 118;1556–1563). Complementary Supplements B-complex: Vitamins B2 and B3 protect glutathione in the eye, and some evidence shows protective beneﬁts with supplements. Boost antioxidant and carotenoid intake by eating lots of berries, carrots, peppers, kale, collard greens, spinach, and broccoli. When a person with celiac disease eats gluten-containing food, the immune sys- tem reacts by producing antibodies, which attack the villi in the small intestine, reducing their ability to absorb nutrients. Over time, the reduced absorption of nutri- C ents leads to malnutrition and vitamin, mineral, and essential fatty acid deﬁciencies. This can damage the health of every organ and body system and increase the risk of many diseases, such as osteoporosis and depression. The cause of celiac is not known; however, three factors are typically present in those who develop the disease: genetic predisposition, a diet containing gluten, and a triggering event. Possible triggers include: introduction of grains into a baby’s diet, puberty, pregnancy, menopause, stress, viral or bacterial infection, and trauma (ac- cident, surgery). There is no cure for celiac disease, but the condition can be managed by following a gluten-free diet for life. Those who do not adhere to a gluten-free diet are at greater risk of developing os- teoporosis; cancer of the intestines, mouth, esophagus, or bowel; and neurological diseases (seizures and nerve damage). Once gluten is removed from the diet, the villi start to heal and intestinal inﬂammation subsides. Complete healing and regrowth of the villi may take several months in younger people and as long as two to three years in older people. For severe cases that don’t respond to dietary changes, medications such as prednisone are temporarily used to suppress the immune response. Vitamin, mineral, and essential fatty acid supplements are recommended to correct deﬁciencies and restore health. Dietary Recommendations Read labels carefully; look for products labelled gluten-free. When eating out, ask to speak directly to the chef as service staff may not be familiar with gluten and the many possible hidden sources. Cross-contamination can occur if gluten-free foods are prepared in unwashed bowls previously containing gluten, or cooked in the same pots or deep-fryer. Foods to include: • Lean meats, ﬁsh and poultry, fruits, vegetables, corn, potato, rice, quinoa, and soy. Healthy fats (ﬁsh, nuts, and seeds) are very important to help restore essential fatty acids, which are depleted in those with celiac disease. Foods to avoid: • Foods containing wheat, barley, rye, bulgur, Kamut, spelt, and triticale, such as breads, pasta, cereals, baked goods, crackers, and pies. Note: Dairy should be limited initially as damage to the intestines reduces the ability to di- gest lactose (dairy sugar). These studies used pure oats, free of gluten contamination, and the amount per day was limited. The Canadian Celiac Association has stated that consump- tion of pure, uncontaminated oats is safe in the amount of 50–70 g per day (1/2–3/4 166 cup of dry rolled oats) by adults and 20–25 g per day (1/4 cup of dry rolled oats) by children with celiac disease. Note: Some individuals may not tolerate even pure oats, in which case they should be completely avoided. Lifestyle Suggestions To promote healing and support immune function, it is important to get adequate rest, reduce stress, and strictly adhere to the gluten-free diet. C Top Recommended Supplements Digestive enzymes: May be depleted in those with celiac; they aid proper digestion of food and are particularly important in newly diagnosed individuals. Essential fatty acids: Are highly recommended to correct deﬁciencies, reduce inﬂammation, and promote healing of intestinal cells. Look for a product that provides both omega-3 (ﬁsh) and omega-6 (borage, primrose) fatty acids. Multivitamin and mineral complex: This is absolutely essential to correct deﬁciencies and promote healing. The most common deﬁciencies include calcium, magnesium, iron, zinc, vitamins D and K, and folic acid. Even those who are stable on a gluten-free diet and in remission may still have nutrient deﬁciencies and would beneﬁt from a supplement. Those with severe malnutrition and deﬁciencies may require higher than typical amounts. Complementary Supplements Fibre: Often deﬁcient in a gluten-free diet due to the elimination of many grains, so supple- ments can help improve bowel function and prevent constipation. Green Food supplement: Provides vitamins, minerals, and ﬁbre; improves energy and recovery. Probiotics: Support intestinal health, restore normal ﬂora, and improve bowel function. Look for a product that is non-dairy, stable at room temperature and provides at least 1 bil- lion live cells. Eat a healthy diet, including fruits, vegetables, lean protein, healthy fats, and glu- ten-free grains. There are various grades of cervical dysplasia, which are classiﬁed upon the extent of the abnormal cell growth. Low-grade cervical dysplasia progresses very slowly and typically resolves on its own. High-grade cervical dyspla- sia tends to progress quickly and usually leads to cervical cancer. An estimated 66 percent of cervical dysplasia cases progress to cancer within 10 years. Cervical cancer constitutes more than 10 percent of cancers worldwide and is the second leading cause of death in women between the ages of 15 and 34. With early identiﬁca- tion, treatment, and consistent follow-up, nearly all cases of cervical dysplasia can be cured and cervical cancer can be prevented. In some cases woman may notice: • Abnormal bleeding • Genital warts • Low back pain • Spotting after intercourse • Vaginal discharge Note: These symptoms are not unique to cervical dysplasia and may indicate a different problem. Every woman should have an annual Pap test beginning at age 18 and con- tinuing on past menopause. Many women stop having this done later in life, which is dangerous since the highest incidence of cervical cancer is among those over age 65. Cervical dysplasia is curable, although the lifetime recurrence rate is 20 percent. For early stages of cervical dysplasia doctors may simply recommend frequent moni- toring, as pre-cancerous changes may disappear on their own. The most commonly used procedures include laser therapy, cryocauterization (use of extreme cold to de- stroy abnormal tissue), and loop excision (using a wire loop to remove tissue). Your doctor takes a little scraping of cells in the cervical area for analysis by a laboratory. These natural therapies do not replace the need for regular medical examinations and doctor’s supervision. Dietary Recommendations Foods to include: • Increase intake of whole grains, fresh vegetables, and fruits. They also contain vitamin C, folate, and beta-carotene, which have been found to be deﬁcient in those who develop cervical dys- plasia. Foods to avoid: • Alcohol, caffeine, reﬁned foods, food additives, sugar, and saturated fats may affect hor- mone balance, impair immune function, and worsen symptoms. C • Red meat and dairy products may contain dioxins and chemicals that act as estrogen- mimickers. Lifestyle Suggestions • Minimize exposure to environmental estrogens or xenoestrogens (phthalates, parabens, and dioxins), which are present in pesticides, plastics, and certain skin care products. Indole-3-carbinol: A compound found naturally in cruciferous vegetables that aids in de- toxiﬁcation of estrogen, protects liver function, and may protect against hormonal cancers. In one study supplements were found to improve lesions in those with cervical dysplasia. Complementary Supplements B-vitamins: Some research has shown that women with low dietary intakes of vitamins B1, B2, B12, and folic acid are at greater risk of developing cervical dysplasia and those with higher intakes of these nutrients from food and supplements are at lower risk. Not speciﬁcally studied for cervical dysplasia, but may help by reducing the harm- ful effects of estrogen.
The greater the area of contact proven 100mg penegra, the stronger are the van der Waals forces purchase penegra online now, and the greater is the amount of energy required to overcome these forces buy 50mg penegra. Thus penegra 50 mg low cost, butane molecules have a greater surface area for interaction with each other than isobutane. It is an unusually strong force of attraction between highly polar molecules in which hydrogen is covalently bonded to nitrogen, oxygen or ﬂuorine. A hydrogen bond is formed whenever a polar covalent bond involving a hydrogen atom is in close proximity to an electronegative atom such as O or N. The attractive forces of hydrogen bonding are usually indicated by a dashed line rather than the solid line used for a covalent bond. Acceptor H H The above diagram shows a cluster of water molecules in the liquid state. Water is a polar molecule due to the electronegativity difference between hydrogen and oxygen atoms. The polarity of the water molecule with the attraction of the positive and negative partial charges is the basis for the hydrogen bonding. Hydrogen bonding occurs with hydrogen atoms covalently bonded to oxygen, ﬂuorine or nitrogen, but not with chlorine, which has larger atom size. The strength of a hydrogen bond involving an oxygen, a ﬂuorine or a nitrogen atom ranges from 3 to 10 kcal/mol, making hydrogen bonds the strongest known type of intermolecular interaction. The intermolecular hydrogen bonding in water is responsible for the unexpectedly high boiling C). Hydrogen bonding is usually stronger than normal dipole forces between molecules, but not as strong as normal ionic or covalent bonds. The nature of the hydrogen bonds in proteins dictates their properties and behaviour. Intramolecular hydrogen bonds (within the molecule) in proteins result in the formation of globular proteins, e. On the other hand, intermolecular hydrogen bonds (between different mole- cules) tend to give insoluble proteins such as ﬁbrous protein. Cellulose, a polysaccharide, molecules are held together through hydrogen bonding, which provides plants with rigidity and protection (see Section 6. A receptor is the speciﬁc chemical constituents of the cell with which a drug interacts to produce its pharmacological effects. One may consider that every protein that acts as the molecular target for a certain drug should be called a receptor. However, this term mainly incorporates those proteins that play an important role in the intercellular communication via chemical messengers. As such, enzymes, ion channels and carriers are usually not classiﬁed as receptors. The term receptor is mostly reserved for those protein structures that serve as intracellular antennas for chemical messen- gers. Upon recognition of the appropriate chemical signal (known as the ligand), the receptor proteins transmit the signal into a biochemical change in the target cell via a wide variety of possible pathways. A minimum three-point attachment of a drug to a receptor site is essential for the desired effect. In most cases, a speciﬁc chemical structure is required for the receptor site and a complementary drug structure. Slight changes in the molecular structure of the drug may drastically change speciﬁcity, and thus the efﬁcacy. However, there are some drugs that act exclusively by physical means outside cells, and do not involve any binding to the receptors. A variety of chemical forces may result in a temporary binding of the drug to its receptor. Interaction takes place by utilizing the same bonding forces as involved when simple molecules interact, e. However, most useful drugs bind through the use of multiple weak bonds (ionic and weaker). Since the drug– receptor interaction is a reversible process, covalent bond formation is rather rare except in a few situations. Anthramycin has a preference for purine–G–purine sequences (purines are adenine and guanine) with bonding to the middle G. Cisplatin, an anticancer drug, is a transition metal complex, cis-diamine-dichloro-platinum. Similarly, the dissociated carboxylic group on the drug can bind with amino groups on the receptor. Ion–dipole and dipole–dipole bonds have similar interactions, but are more complicated and are weaker than ionic bonds. Formation of hydrophobic bonds between nonpolar hydrocarbon groups on the drug and those in the receptor site is also common. Although these bonds are not very speciﬁc, the interactions take place to exclude water molecules. Repulsive forces that decrease the stability of the drug–receptor interaction include repulsion of like charges and steric hindrance. Chemistry for Pharmacy Students Satyajit D Sarker and Lutfun Nahar # 2007 John Wiley & Sons, Ltd. A clear understanding of stereochemistry is crucial for the study of complex mole- cules that are biologically important, e. Before we go into further detail, let us have a look at different types of isomerism that may exist in organic molecules. For example, 1-butene and 2-butene have the same mole- cular formula, C4H8, but structurally they are different because of the different positions of the double bond. For example, ethanol and dimethylether have same molecular formula, C2H6O, but they differ in the sequence of bonding. For example, in a-glucose and b-glucose, the atoms are connected in the same order, but the three 3. Similarly, cis- and trans-cinnamic acid only differ in the three dimensional orientation of the atoms or groups. Conﬁgurational isomers include optical isomers, geometrical isomers, enantiomers and diastereomers. Conformational isomers Atoms within a molecule move relative to one another by rotation around single bonds. Such rotation of covalent bonds gives rise to different conforma- tions of a compound. Conformational isomerism can be presented with the simplest example, ethane (C2H6), which can exist as an inﬁnite number of conformers by the 3 rotation of the C–C s bond. Ethane has two sp -hybridized carbon atoms, and the tetrahedral angle about each is 109. The most signiﬁcant conformers of ethane are the staggered and eclipsed conformers. H H H H H H Rotation about the C-C bond in ethane Visualization of conformers There are four conventional methods for visualization of three-dimensional structures on paper. These are the ball and stick method, the sawhorse method, the wedge and broken line method and the Newman projection method. Using these methods, the staggered and eclipsed conformers of ethane can be drawn as follows. At any moment, more molecules will be in staggered form than any other conformation. Torsional energy and torsional strain Torsional energy is the energy required for rotating about the C–C s bond. Torsional strain is the strain observed when a conformer rotates away from the most stable conformation (i. Torsional strain is due to the slight repulsion between electron clouds in the C–H bonds as they pass close by each other in the eclipsed conformer. The energy difference between the eclipsed and staggered forms of propane is greater than that of ethane.
Those on a strict vegetarian diet may also have difﬁculty in getting enough essential nutrients from diet alone effective penegra 50 mg. Taking a daily multivitamin ensures that your body gets all the essential nu- trients it needs to function optimally purchase genuine penegra online. For example: • Children who are picky eaters could be lacking in various nutrients buy 50 mg penegra visa, such as vitamin C and iron proven 50mg penegra. Vitamin B12 and other B vitamins may be deﬁcient in older individuals depending on diet, medical conditions, and prescription drug use. Chapter 2 provides extensive information on vitamins and minerals, including dos- age ranges based on age and gender, as well as nutrients that may be depleted by prescription drugs or certain health conditions. Principles of Safe Supplementing | 69 Green Foods Most people ﬁnd it difﬁcult to consume the recommended seven to 10 servings of fruits and vegetables per day that provide our primary dietary source of vitamins and minerals. To complement your diet, you may want to consider taking a green foods supplement. Green foods such as chlorella, spirulina, barley grass, and wheat grass provide vital nutrients such as antioxidants, minerals, and ﬁbre, which can help boost energy levels, support detoxiﬁcation, and enhance well-being. You can add your greens+ to your morning pro- tein shake, or mix with juice or water. They are required for growth and development of the brain, nervous system, adrenal glands, sex organs, and eyes. They maintain the health of cell membranes, produce hormones and brain chemicals, and regulate various cell processes. Omega-3s are present in ﬁsh and, to a lesser extent, in some plants (ﬂaxseed and leafy green vegetables). Omega-3 deﬁciency is thought to be quite common, and supplementing with omega-3s offers a number of health beneﬁts, such as reducing the risk of heart attack, and improving brain function and skin health. Omega-3 supplements are also recommended for women who are trying to get preg- nant or who are pregnant as these good fats are essential to the growing brain, eyes, and nervous system of the baby. Look for a pharmaceutical- grade, cold-pressed ﬁsh oil from a reputable manufacturer. For example, if you have osteoporosis, you may require extra minerals, vitamin D, and other nutrients. If you have heart disease, it would be wise to take coenzyme Q10 along with extra antioxidants. In Section 3 I provide concise guidelines on supplement recommendations for various health conditions. Keep in mind that it is always wise to consult with a professional for advice on which supple- ments to take, the appropriate dosage, and any precautions. Do’s • Research your options—consult with your pharmacist or health care provider and ﬁnd out as much as you can about the products you are considering. In particular ask if there are any possible interactions with medications or side effects. This will keep the amount of pills you take to a minimum and will also be easier on your budget. Depending on your diet and needs, you may still need to take additional vitamin C, E, and cal- cium as it is difﬁcult to ﬁt all of these nutrients into one tablet. Don’ts • Don’t take supplements with sugar, starch, corn, wheat, iron, dairy, salt, artiﬁcial ﬂavourings and colourings (dyes), and preservatives. These are unnecessary ingre- dients that can cause allergic reactions in some people. Some vitamins are more expensive due to company marketing and advertising costs and are not necessarily made with bet- ter ingredients. After that, ask yourself what’s missing from your diet and what concerns you the most about your health. Focus on one concern at a time, exploring different nutritional supplements that may offer help. If you invest the time into creat- ing a supplement program that’s right for your individual needs, your reward should be improved quality of life. In the last 20 years, there has been a strong resurgence of homeopathy, which has become the fastest-growing ﬁeld of integrative medicine in Canada, and is the second most popular form of any medicine worldwide. Even though the nature of homeopathy, its scope, and its applications in health care are less understood in Canada, it remains clear that more than ever, Canadians are turning to homeopathy as an addition to their preventative routines as well as a solution to their most common health complaints. Homeopathy is part of a trillion- dollar, North American natural health care industry. Homeopathic medicine is second in popularity only to mainstream or conventional medicine. Because homeopathy is an inexpensive alternative with little proﬁt margin and no possibility for patenting, its marketability to mainstream practitioners is low, so few are aware of its beneﬁts in a clinical setting. Contemporary Canadian society’s newfound understanding of health care as preven- tion of disease has led to a new perspective of natural approaches like homeopathy as mainstream. In line with this new deﬁnition of health care, homeopathy helps the body to do what it should be able to do on its own to keep the body healthy and free of disease. Conventional approaches, such as drugs and surgery, are sometimes necessary, but these approaches should soon become known as the complementary approach! For over 200 years, Canadians have been using homeopathic medicines suc- cessfully to treat acute and chronic illnesses. Interestingly, homeopaths were recognized under government structure before practitioners of conventional med- icine. In Upper Canada in 1859, homeopathic doctors were acknowledged and regulated under the Act Respecting Homeopathy. In 1865, An Act to Regulate the Qualiﬁcations of Practitioners in Medicine and Surgery in Upper Canada was pro- claimed. A clause in this act prohibited any repeal or action that would in any way affect the Homeopathic Act of 1859 and the Eclectic Act of 1861. In 1866, An Act Respecting the Medical Board and Medical Practitioners authorized the 74 | Chapter 9 formation of a licensing board for conventional doctors, exempting homeopaths and midwives. As a consequence of these two acts, the Council of Education and Registration of Upper Canada was established in 1866, with the authority to grant licences to practise medicine in Upper Canada. Homeopathic medicines are micro doses of plant, mineral, and other naturally occurring substances. They are regulated by Health Canada and are manufactured ac- cording to the highest drug safety standards. Homeopathic medicines are safe and efﬁcient with no side effects and no drug interactions, allowing people to take conventional medications, if necessary, at the same time as their homeopathic treatment. In this way, homeopathy is able to help the body regain balance by get- ting it to do better what it is already equipped to do on its own. If necessary, when disease has progressed too far, conventional approaches like drugs and surgery may be prudent to use adjunctively. The ﬁrst is the law of similars, which states that the same things that cause an illness will ultimately cure it. The second is that inﬁnitesimal doses are all that are needed to trigger the body’s natural defence system. The third is that homeopathic medicines are prescribed in a very individualized way, taking into account not only physical symptoms but also the patient’s behavioural and mental/emotional condition. Scientiﬁc studies have demonstrated that highly diluted biological products (ho- meopathic medicines) can have a veriﬁable effect on humans. Homeopathy offers a simple, effective, and safe medical therapy free from known side effects. While it is always good to consult with a qualiﬁed practitioner, there are many homeopathic remedies that are safe for self-medication. Research centres around the world are conducting studies of homeopathic medi- cines and a growing number of these studies are being published in peer-reviewed journals. One of many such studies that has become very well known was published in The Lancet in 1997. The authors concluded that “The results of this meta-analysis are not compatible with the hypothesis that the clinical effects of homeopathy are completely due to placebo. Oddly enough, these and other trials and studies have not been given sufﬁcient prominence, either within the scientiﬁc community or by media.Share this