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Some drugs act through simple physical or chemical reactions without interacting with any receptor buy viagra gold 800 mg. Many drugs are similar to or have similar chemical groups to the naturally occurring chemical and have the ability to bind onto a receptor where one of two things can happen- either the receptor will respond or it will be blocked buy cheap viagra gold 800 mg on line. A drug discount generic viagra gold canada, which is able to fit onto a receptor, is said to have affinity for that receptor. An agonist has both an affinity and efficacy whereas antagonist has affinity but not efficacy or intrinsic activity. When a drug is able to stimulate a receptor, it is known as an agonist and therefore mimics the endogenous transmitter. When the drug blocks a receptor, it is known as antagonist and therefore blocks the action of the endogenous transmitter (i. However, as most drug binding is reversible, there will be competition between the drug and the natural stimulus to the receptor. The forces that attract the drug to its receptor are termed chemical bonds and they are (a) hydrogen bond (b) ionic bond (c) covalent bond (d) Vander waals force. Covalent bond is the strongest bond and the drug-receptor complex is usually irreversible. Dose Response relationship The exact relationship between the dose and the response depends on the biological object under observation and the drug employed. When a logarithm of dose as abscissa and responses as ordinate are constructed graphically, the “S” shaped or sigmoid type curve is obtained. The lowest concentration of a drug that elicits a response is minimal dose, and the largest concentration after which further increase in concentration will not change the response is the maximal dose. Graded dose effect: As the dose administered to a single subject or tissue increases, the pharmacological response also increases in graded fashion up to ceiling effect. Quantal dose effect: It is all or none response, the sensitive objects give response to small doses of a drug while some will be resistant and need very large doses. The quantal dose- effect curve is often characterized by stating the median effective dose and the median lethal dose. Penicillin has a very high therapeutic index, while it is much smaller for the digitalis preparation. Structural activity relationship The activity of a drug is intimately related to its chemical structure. Knowledge about the chemical structure of a drug is useful for: (i) Synthesis of new compounds with more specific actions and fewer adverse reactions (ii) Synthesis of competitive antagonist and (iii) Understanding the mechanism of drug action. Slight modification of structure of the compound can change the effect completely. Pharmacokinetics Pharmacokinetics deals with the absorption, distribution, metabolism and excretion drugs in the body. Biotransport of drug: It is translocation of a solute from one side of the biological barrier to the other. Structure of biological membrane: The outer surface of the cell covered by a very thin structure known as plasma membrane. The 5 membrane proteins have many functions like (a) contributing structure to the membrane (b) acting as enzyme (c) acting as carrier for transport of substances (d) acting as receptors. The plasma membrane is a semipermeable membrane allowing certain chemical substances to pass freely e. Drug absorption: Absorption is the process by which the drug enters in to the systemic circulation from the site of administration through biological barrier. In case of intravenous or intra-arterial administration the drug bypasses absorption processes and it enters into the circulation directly. Routes of drug administration: a) From the alimentary tract: (i) Buccal cavity: e. Disadvantages of oral route: Onset of drug action is slow, irritant drugs cannot be administered and it is not useful in vomiting and severe diarrhea, gastric acid and digestive enzymes may destroy some drugs, and water soluble drugs are absorbed poorly. Disadvantages: Pain at local site of injection, the volume of injection should not exceed 10 ml. Advantages: It can be given in large volumes, production of desired blood concentration can be obtained with a well designed dose. Disadvantages: Drug effect cannot be halted if once the drug is injected, expertise is needed to give injection. Bioavailability: It is the rate and amount of drug that is absorbed from a given dosage form and reaches the systemic circulation following non-vascular administration. The route of administration largely determines the latent period between administration and onset of action. Drugs given by mouth may be inactive for the following reasons: a) Enzymatic degradation of polypeptides within the lumen of the gastrointestinal tract e. Factors affecting drug absorption and bioavailability: a) Physico-chemical properties of drug b) Nature of the dosage form c) Physiological factors d) Pharmacogenetic factors e) Disease states. However at the cell surface, the lipid soluble drugs penetrate into the cell more rapidly than the water soluble drugs. Unlike inorganic compounds, the organic drugs are not completely ionized in the fluid. Unionized component is predominantly lipid soluble and is absorbed rapidly and an ionized is often water soluble component which is absorbed poorly. T is impermeable to the ionized form of a weak organic acid or a weak organic base. Disintegration time: The rate of break up of the tablet or capsule into the drug granules. Fillers may not be totally inert but may affect the absorption as well as stability of the medicament. Thus a faulty formulation can render a useful drug totally useless therapeutically. However certain irritant drugs like salicylates and iron preparations are deliberately administred after food to minimize the gastrointestinal irritation. Calcium present in milk and in antacids forms insoluble complexes with the tetracycline antibiotics and reduces their absorption. Thus a drug though absorbed well when given orally may not be effective because of its extensive first pass metabolism. Bioavailability curves Single dose bioavailability test involves an analysis of plasma or serum concentration of the drug at various time intervals after its oral administration and plotting a serum concentration time curve. Formation B = Effect would last much longer and nontoxic Formulation C = gives inadequate plasma level so therapeutically ineffective. Definition: Penetration of a drug to the sites of action through the walls of blood vessels from the administered site after absorption is called drug distribution. Drugs distribute through various body fluid compartments such as (a) plasma (b) interstitial fluid compartment (c) trans-cellular compartment. Protein binding of drug: A variable and other significant portion of absorbed drug may become reversibly bound to plasma proteins.

In this study conducted by Sargent (2005) buy viagra gold 800 mg amex, clear proof was given of the association between witnessing scenes of smoking in movies and the tobacco use among adolescents buy generic viagra gold 800mg line. The results conclude that there is a link between exposure to drinking scenes and subsequent alcohol consumption order viagra gold line. Hanewinkel and Sargent (2009) conducted one of the few longitudinal studies on the effect of exposure to audiovisual content in drinking behavior. They measured the prevalence of alcohol consumption in a sample of 2,708 German adolescents who had never consumed alcohol. A year later the rate of television exposure was measured, taking into account whether the youth had television in his or her room and whether he or she had seen movies in which alcohol was drunk, among other variables, and compared with the problematic use of alcohol. The authors concluded that the exposure and having television in the room are independent predictors of problematic alcohol consumption. Other authors define community prevention as all activities carried out in the community setting that stimulate the participation of community representatives or institutions (e. The community context offers a wide range of actuation that can be defined by exclusion from other areas; and therefore, it encompasses everything that is not reserved for more specific areas such as school, family or workplace, to cite the most common areas. One might include the following as the main settings of actuation for community prevention: recreational night life, media, 18 Daniel Lloret Irles and José Pedro Espada Sánchez public urban spaces and public facilities. Developed within these areas are preventive interventions aimed at promoting healthy lifestyles and reducing the influence of those social conditions likely to cause damage, discomfort or tension. Although the legal framework implies a differentiating element, similar preventive principles apply in both cases and the measures and techniques used are aimed at reducing the availability and fostering a social attitude against substance use. Typology of Community Level Prevention Programs The community context provides an extensive panorama of possibilities for intervention. The range of social segments that are accessible through the community context, the emergence of new supports and the definition of new objectives, make attempts to classify the variety of channels and formats used by community prevention inscrutable. A possible classification could be the classic primary, secondary and tertiary one that takes into account the relationship of the target population with drug use. From this perspective, interventions are organized into three levels: universal, selective or indicated. Taking as criterion the format adopted by the program or preventive intervention and the medium used to reach the target population, we arrive at one of the possible classifications which, like any other, contain a certain degree of overlap that make it inexact. According to this criterion, we can sort interventions into four types: a) Interventions through the media. Interventions through the Media Interventions in the media adopt many different formats ranging from short and repeated messages –advertising spots-to more elaborate areas such as reports and interviews. This type of intervention aims to inform and encourage individuals towards a reflection aimed at abstinence, while reinforcing the various prevention actions and programs carried out in specific spheres and the communicative actions launched from the various social communication supports. As with other types of actions, their effectiveness is enhanced when coordinated with more structured prevention programs. There is sufficient evidence on the effectiveness of brief interventions in the media (Derzon and Lipsey, 2002, Longshore, Ghosh-Dastidar and Ellickson, 2003). Analysis of the assessment of the effectiveness of preventive ad exposure concluded a reduction in the likelihood of marijuana, crack and cocaine consumption (Block, Morwitz, Putsis and Sen, 2002). Apart from the content of preventive messages, it becomes necessary to revise the traditional formats of these messages designed for classical media supports (i. The new information and communication technologies offer the possibility to participate in communicative discourse, which increases audience involvement. Empirical evidence maintains that prevention programs that include dynamic and participatory components are more effective than those based on the mere transmission of information. Internet: A new support, a new generation of continuous change Within the broad field of care and prevention of problems arising from drug use, the Internet is turning out to be a breakthrough; since, it facilitates the exchange of knowledge and experience among professionals on the one hand, and on the other the implementation of on-line preventive programs destined for society in general. In this way, the Internet can serve as a medium in which 20 Daniel Lloret Irles and José Pedro Espada Sánchez particular preventive programs are developed, or it can also be a support tool at the service of teachers within the educational framework and parents within the bosom of the family. Prevention programs with the format of web pages provide information, data, and actuation models and offer the following advantages over a traditional format (Lacoste et al. It is an interactive medium that turns the final recipient of the message into a co-author, because he or she can actively collaborate by providing and/or modifying content. It is the communication channel used by young people today, and it will be the form of communication of upcoming generations. Browsing the Internet and feeling part of that virtual world, in which you can find everything under the sun, continues to be one of the greatest attractions of this communication technology. This is very difficult to obtain without the speed and immediacy of the world of links and hypertextuality. Since the inception of the Internet, professionals concerned about public health have used the online format to inform and sensitize the public about the consequences of drug consumption or other deviant behavior. However, only since a few years ago do we find initiatives designed to reach and capture the 21 Analysis of Drug Use Prevention on a Community-wide Scale attention of a young target audience by taking their audiovisual tendencies into account (Garcia del Castillo y Segura, 2009). In this sense, we believe the productions that stand out meet the dual objectives of spreading knowledge based on scientific evidence and transmitting information as a prevention tool. Some examples are: - The Spanish Association against Cancer publishes on its website an info- graphic video on the path of tobacco smoke and its effects along its path inside the body. Mediator training programs This type of action consists of the training of mediators and leaders in the skills needed to produce a transmission of values and attitudes seeking a snowball effect. The mediator acts as a catalyst for social change processes that are considered necessary for the achievement of preventive goals. Generally, the task of the social mediator in community interventions is not to impart knowledge or direct the training process of participants, but rather to put them in a position to learn without becoming the protagonist of their learning. The mediator must be mindful of motivating, facilitating, and eliminating obstacles, clearly showing the ability of groups to solve problems, yet all without directing or offering solutions. In principle, there are a large number of social agents who can exercise the role of mediator: teachers, health 22 Daniel Lloret Irles and José Pedro Espada Sánchez or social professionals, members of religious orders, volunteers, etc. Although there is no profile that ensures optimum performance by the mediator, it seems clear that in no case be must mediators be arrogant, manipulative or incoherent, paternalistic, inflexible or rigid, or biased; neither must they consider themselves essential, nor believe that they are a savior, nor maintain closed or circular discourse. By contrast, the social mediator must show maturity and personal balance, capacity for continuous analysis of reality, critical and creative ability, knowledge of the immediate environment, capacity for teamwork, ability to manage and plan social activities, capacity to relate to the community, capacity for dialogue and communication, some psycho-pedagogic training and ability to dynamize social, group and personal life. Community action groups Community action groups are associations or nonprofit organizations formed to carry out projects of interest in the community. Often these types of social initiatives arise from the interest and motivation of a few, generally those affected by the problem to be resolved. Public interest in the group´s action and the spreading of their work permit others to join and collaborate in the effort. Created to deal with a social problem, they offer advisory assistance and social support to people who are in similar situations and participating in preventive campaigns. Other established and active groups, such as certain neighborhood associations, have taken among their objectives the fight against social scourges and also the prevention of drug dependencies. Accordingly, they have incorporated actions with preventive intentions into their repertoire of activities, which they carry out in their work environment. Plans and strategies to combat drug use commonly include objectives aimed at promoting social participation; to meet these objectives, organizations are provided with budgets to carry out preventive work. Thus, we find in the 23 Analysis of Drug Use Prevention on a Community-wide Scale current "European Union Drugs Action Plan for 2009-2012" objectives aimed at promoting citizenry participation.

In response generic 800 mg viagra gold otc, aldosterone increases the excretion of K and the retention of Na buy viagra gold uk, which in turn increases blood volume and blood pressure cheap viagra gold on line. Renin then catalyzes the conversion of the blood protein angiotensinogen, produced by the liver, to the hormone angiotensin I. Hormones of the Zona Fasciculata The intermediate region of the adrenal cortex is the zona fasciculata, named as such because the cells form small fascicles (bundles) separated by tiny blood vessels. The cells of the zona fasciculata produce hormones called glucocorticoids because of their role in glucose metabolism. Their overall effect is to inhibit tissue building while stimulating the breakdown of stored nutrients to maintain adequate fuel supplies. In conditions of long-term stress, for example, cortisol promotes the catabolism of glycogen to glucose, the catabolism of stored triglycerides into fatty acids and glycerol, and the catabolism of muscle proteins into amino acids. These raw materials can then be used to synthesize additional glucose and ketones for use as body fuels. The hippocampus, which is part of the temporal lobe of the cerebral cortices and important in memory formation, is highly sensitive to stress levels because of its many glucocorticoid receptors. You are probably familiar with prescription and over-the-counter medications containing glucocorticoids, such as cortisone injections into inflamed joints, prednisone tablets and steroid-based inhalers used to manage severe asthma, and hydrocortisone creams applied to relieve itchy skin rashes. These drugs reflect another role of cortisol—the downregulation of the immune system, which inhibits the inflammatory response. Hormones of the Zona Reticularis The deepest region of the adrenal cortex is the zona reticularis, which produces small amounts of a class of steroid sex hormones called androgens. In adult women, they may contribute to the sex drive, but their function in adult men is not well understood. In post-menopausal women, as the functions of the ovaries decline, the main source of estrogens becomes the androgens produced by the zona reticularis. Adrenal Medulla As noted earlier, the adrenal cortex releases glucocorticoids in response to long-term stress such as severe illness. Epinephrine is produced in greater quantities—approximately a 4 to 1 ratio with norepinephrine—and is the more powerful hormone. Because the chromaffin cells release epinephrine and norepinephrine into the systemic circulation, where they travel widely and exert effects on distant cells, they are considered hormones. Both epinephrine and norepinephrine signal the liver and skeletal muscle cells to convert glycogen into glucose, resulting in increased blood glucose levels. These hormones increase 762 Chapter 17 | The Endocrine System the heart rate, pulse, and blood pressure to prepare the body to fight the perceived threat or flee from it. It also prompts vasodilation, further increasing the oxygenation of important organs such as the lungs, brain, heart, and skeletal muscle. At the same time, it triggers vasoconstriction to blood vessels serving less essential organs such as the gastrointestinal tract, kidneys, and skin, and downregulates some components of the immune system. Hormones of the Adrenal Glands Adrenal gland Associated hormones Chemical class Effect Adrenal cortex Aldosterone Steroid + Increases blood Na levels Adrenal cortex Cortisol, corticosterone, cortisone Steroid Increase blood glucose levels Adrenal medulla Epinephrine, norepinephrine Amine Stimulate fight-or-flight response Table 17. For example, Cushing’s disease is a disorder characterized by high blood glucose levels and the accumulation of lipid deposits on the face and neck. Other common signs of Cushing’s disease include the development of a moon-shaped face, a buffalo hump on the back of the neck, rapid weight gain, and hair loss. Chronically elevated glucose levels are also associated with an elevated risk of developing type 2 diabetes. In addition to hyperglycemia, chronically elevated glucocorticoids compromise immunity, resistance to infection, and memory, and can result in rapid weight gain and hair loss. In contrast, the hyposecretion of corticosteroids can result in Addison’s disease, a rare disorder that causes low blood glucose levels and low blood sodium levels. The signs and symptoms of Addison’s disease are vague and are typical of other disorders as well, making diagnosis difficult. They may include general weakness, abdominal pain, weight loss, nausea, vomiting, sweating, and cravings for salty food. Inferior but somewhat posterior to the thalamus is the pineal gland, a tiny endocrine gland whose functions are not entirely clear. The pinealocyte cells that make up the pineal gland are known to produce and secrete the amine hormone melatonin, which is derived from serotonin. In contrast, as light levels decline—such as during the evening—melatonin production increases, boosting blood levels and causing drowsiness. The secretion of melatonin may influence the body’s circadian rhythms, the dark-light fluctuations that affect not only sleepiness and wakefulness, but also appetite and body temperature. Interestingly, children have higher melatonin levels than adults, which may prevent the release of gonadotropins from the anterior pituitary, thereby inhibiting the onset of puberty. Jet lag occurs when a person travels across several time zones and feels sleepy during the day or wakeful at night. Traveling across multiple time zones significantly disturbs the light-dark cycle regulated by melatonin. It can take up to several days for melatonin synthesis to adjust to the light-dark patterns in the new environment, resulting in jet lag. The primary hormone produced by the male testes is testosterone, a steroid hormone important in the development of the male reproductive system, the maturation of sperm cells, and the development of male secondary sex characteristics such as a deepened voice, body hair, and increased muscle mass. The primary hormones produced by the ovaries are estrogens, which include estradiol, estriol, and estrone. Estrogens play an important role in a larger number of physiological processes, including the development of the female reproductive system, regulation of the menstrual cycle, the development of female secondary sex characteristics such as increased adipose tissue and the development of breast tissue, and the maintenance of pregnancy. Another significant ovarian hormone is progesterone, which contributes to regulation of the menstrual cycle and is important in preparing the body for pregnancy as well as maintaining pregnancy. The placenta supplies oxygen and nutrients to the fetus, excretes waste products, and produces and secretes estrogens and progesterone. Commonly used for performance enhancement, anabolic steroids are synthetic versions of the male sex hormone, testosterone. The use of performance-enhancing drugs is banned by all major collegiate and professional sports organizations in the United States because they impart an unfair advantage to athletes who take them. For example, anabolic steroid use can increase cholesterol levels, raise blood pressure, and damage the liver. Altered testosterone levels (both too low or too high) have been implicated in causing structural damage to the heart, and increasing the risk for cardiac arrhythmias, heart attacks, congestive heart failure, and sudden death. Paradoxically, steroids can have a feminizing effect in males, including shriveled testicles and enlarged breast tissue. In females, their use can cause masculinizing effects such as an enlarged clitoris and growth of facial hair. In both sexes, their use can promote increased aggression (commonly known as “roid-rage”), depression, sleep disturbances, severe acne, and infertility. Although it is primarily an exocrine gland, secreting a variety of digestive enzymes, the pancreas has an endocrine function. Its endocrine function involves the secretion of insulin (produced by beta cells) and glucagon (produced by alpha cells) within the pancreatic islets. Cells and Secretions of the Pancreatic Islets The pancreatic islets each contain four varieties of cells: • The alpha cell produces the hormone glucagon and makes up approximately 20 percent of each islet. Glucagon plays an important role in blood glucose regulation; low blood glucose levels stimulate its release.

Deposition of foreign particles depends on their size: inhalation of very small particles does not result in absorption through the alveoli or bronchial system buy viagra gold 800mg mastercard. Much larger particles are either not able to enter the respiratory system or are deposited in the upper respiratory tract (Figure 1A) order online viagra gold. The respiratory tract is covered with a mucociliary layer con- sisting of ciliated cells generic 800mg viagra gold, mucus-secreting cells and glands (Figure 1 B). Foreign par- ticles in the nasal cavity or upper respiratory tract are trapped in mucus, carried back to the throat, and swallowed. From the lower respiratory tract foreign particles are brought up by the ciliary action of epithelial cells. In the alveoli that lack cilia or mucus, macrophages are responsible for destroying particles (Figure 1). Binding to the host cells The main targets of the influenza virus are the columnar epithelial cells of the respi- ratory tract. However, this simplified model is often insufficient to explain viral tropism since the receptor distribution in the host is generally more widespread than the observed virus tro- pism. Hosts may prevent the attachment by several mechanisms: (1) specific immune response and secretion of specific IgA antibodies, (2) unspecific mechanisms, such as mucociliary clearance or production of mucoproteins that able to bind to viral hemagglutinin, and (3) genetic diversifi- cation of the host receptor (sialic acid), which is highly conserved in the same spe- cies, but differs between avian and human receptors (Matrosovich 2000). As a re- sult, the avian virus needs to undergo mutations at the receptor binding site of he- magglutinin to cross the interspecies barrier between birds and humans. In pigs, polymorphisms of sialic acid species and linkage to galactose of both humans and birds are co-expressed in the tissue. Therefore, co-infection with avian and human influenza can occur in pigs and allow genetic reassortment of antigenic properties of both species in the co-infected cells. Recently, it has been shown that certain avian influenza viruses in human and birds are able to bind to different target cells (Matrosovich 2004). This could explain the observation of several cases since the end of the 1990s with transmission of avian influenza directly from poultry to hu- mans. H5N1 and some other subtypes of influenza A virus are able to bind to re- ceptors in the human eye (Olofson 2005). Pathogenesis 95 As essential as the binding of the influenza virus is its cleavage from the binding site at the host cell. The virulence of the influenza virus depends on the compatibility of neura- minidase with hemagglutinin. A virulent virus which has undergone mutations in the hemagglutinin needs compensatory mutations in the neuraminidase to maintain its virulence (Baigent & McCauley 2003, Hulse 2004). As a consequence, viral fitness and virulence were found to be reduced in influenza viruses resistant to neu- raminidase inhibitors (Yen 2005). Once the cell membrane and the virus have been closely juxtaposed by virus- + receptor interaction, the complex is endocytosed. Cellular proteases are often required to cleave viral proteins to form the mature in- fectious virus particle. In humans, the replication of the influenza virus is generally restricted to the epithelial cells of the upper and lower respiratory tract. This is be- cause of the limited expression of serine protease, tryptase Clara, secreted by non- ciliated Clara cells of the bronchial epithelia. This may cause altered tropism and additional sites of rep- lication in animals and humans (Gamblin 2004). Thus, H5N1 viral replication in humans may be restricted to the respiratory and intestinal tract in contrast to disseminated infections documented in other mammals and birds. Once influenza has efficiently infected respiratory epithelial cells, replication oc- curs within hours and numerous virions are produced. Infectious particles are pref- erentially released from the apical plasma membrane of epithelial cells into the air- ways by a process called budding. This favors the swift spread of the virus within the lungs due to the rapid infection of neighboring cells. This would explain why many of the individuals infected with avian influenza (H5N1) in Hong Kong had gastrointestinal, hepatic, and renal, as well as respiratory symptoms and why viruses from these patients were neurovirulent in mice (Park 2002). Whether these symptoms result from hematogenic spread or reflect non-pulmonal means of viral entry into the host re- mains unclear. These findings suggest a means by which influenza A viruses, and perhaps other viruses as well, could become highly pathogenic in humans. Finally, animal studies have revealed that the site of inoculation can determine the pathway of spread of the influenza virus in the host. Although a frequent disease, the specific inflammatory patterns or regulation of immune response and the pathogenesis of cytopathic effects in human influenza is incompletely understood. Cytokines and fever A central question is how an infection essentially localized to the respiratory tract can produce such severe constitutional symptoms. As in many other infectious dis- eases, it is the unspecific and adaptive immune response that contributes substan- tially to the clinical signs and symptoms in influenza and finally to the control of infection. Cytokines, rapidly produced after infection by epithelial and immune cells of the respiratory mucosa, are local hormones that activate cells, especially within the immune system. For example, influenza infection induces in human plasmacytoid and myeloid dendritic cells a chemokine secretion program which allows for a coordinated attraction of the different immune effectors (Piqueras 2005, Schmitz 2005). Most of these cytokines have been detected in nasopharyngeal washes of humans who have been experimentally or naturally infected with influenza (Brydon 2005). It is proposed that these cytokines, produced locally or systemically following in- teraction of exogenous pyrogens (e. There is a small area in the hypothalamus, called the Organum vasculosum laminae terminalis, which has a reduced blood-brain-barrier and allows the passage of pyrogens. At this site, in a dose-dependent manner, they induce the production of prostaglandins and especially prostaglandin E2. These mediators in- crease the thermostatic set point and trigger complex thermoregulatory mechanisms to increase body temperature. The fact that none of the cytokines mentioned above correlated with the severity of disease in influenza infection, argues in favor of their pleiotropy and cross-talk amongst signaling pathways. Individual virion components were, however, not pyrogenic probably explaining why whole virus vaccines can produce influenza-like symp- toms while subunit vaccines do not (Brydon 2005). Respiratory symptoms Hyperreactivity of the bronchial system (Utell 1980, Little 1978), obstruction pre- dominantly of small airways (Hall 1976) and impaired diffusion capacity (Horner 1973) is common in influenza infection. Hyperreactivity and broncho-obstruction may persist for a prolonged period, especially in allergic disease (Kondo & Abe 1991), and might be a result of a pro-inflammatory cytokine profile which interferes with the ability to induce tolerance to aerosolized allergens (Tsitoura 2000). In human influenza infection, severe alveolar inflammation presenting as primary viral pneumonia, is rare. It usually presents with extended inflammation of both lower and upper respiratory tracts with loss of ciliated cells, and imposed hypere- mic or hemorrhagic areas on hyaline membranes and infiltrates of neutrophils and mononuclear cells (Yeldandi & Colby 1994). In contrast to primary viral pneumonia, bacterial superinfection is common in hu- man influenza and causes serious morbidity and mortality predominantly in elderly adults. Several factors have been identified, which could explain the increased risk for bacterial infection of the respiratory tract, including damage of columnar epithelial cells with disruption of the epithelial cell barrier (Mori 1995), decreased mucociliary clearance (Levandovsi 1985), enhancement of bacterial adherence (McCullers 2002), and functional alteration of neutrophils (Abramson 1986, Cas- sidy 1988).

M. Umul. Nazarene Bible College.