By G. Nerusul. Rochester Institute of Technology.
These are the ‘micronutrients’ that are necessary to help the body in all its functions buy discount kamagra polo 100 mg on line, including reproduction generic kamagra polo 100 mg, and to make sure that it can ﬁght infection. People need micronutrients so they can use their brains and have the energy to keep their body working as well as possible. Your job as a Health Extension Practitioner will involve helping people to understand the importance of these components in a diverse diet. Among these micronutrients, three have obtained worldwide attention due to their high public health signiﬁcance. If people don’tgetsufﬁcient vitamin A, iodine and iron, this can lead to grave health as well as social and economic consequences. In this session you will learn more about these micronutrients, as well as the extent and consequences of their deﬁciency. You will also learn how to prevent and treat the major micronutrient deﬁciencies in your community. Learning Outcomes for Study Session 7 When you have studied this session, you should be able to: 7. Vitamins are necessary in small amounts in our diet to facilitate growth, maintenance of health and reproduction. Although minerals make up only a small portion of body tissues, they are essential for normal growth and functioning. Because only very minute quantities of vitamins and minerals are needed for health, they are called micronutrients. These elements are essential; they cannot be manufactured by the human body and must be obtained through 79 dietary means. Among these micronutrients, three have obtained worldwide attention and are the focus of this study session due to their high public health signiﬁcance. Vitamin A, iodine and iron deﬁciencies lead to grave health, social and economic consequences; but the good news is that there are cost- effective strategies to overcome these deﬁciencies. You can also work with the women in your village to help identify potential problems and families who need support. The overall goals and objectives of the prevention and treatment of micronutrient deﬁciencies in Ethiopian are shown in Box 7. To increase coverage of the programmes that improve the micronutrient status of the population. In Ethiopia, one out of every 1000 people is affected and about 50,000 prenatal deaths occur yearly due to iodine deﬁciency disorder. This is in part because of the marked decrease in the amount of iodised salt being consumed in Ethiopian households compared with a decade ago. Anaemia is a widespread health problem affecting more than two billion people worldwide — one third of the world’s population. More than half 80 Study Session 7 Preventing Micronutrient Problems in Ethiopia (54%) of Ethiopian children age 6-9 months and 27 % of Ethiopian women aged 15-49 are anaemic (mainly due to low blood iron status). Iron deﬁciency can delay muscular and nervous system development and mental performance, especially in preschool age children. In adults, anaemia reduces work capacity, mental performance and reduces tolerance to infections. Iron deﬁciency anaemia can also cause increased maternal mortality due to bleeding problems. Maternal anaemia can lead to prenatal infant loss, low birth weight, and pre-term births. Ask teachers if there are children who miss school (children with anaemia may be too tired to attend). Ask family members if there are mothers and children who ﬁnd it difﬁcult to see after dusk and if children frequently get sick (possible signs of vitamin A deﬁciency). Ask community leaders/families if there are any children/adolescents who have swelling in front neck area (goitre: a sign of iodine deﬁciency). Salt iodisation will improve the physical and mental development of millions of people. The intellectual and cognitive development of whole generations of Ethiopian children will be reduced by around 10% unless adequate iodine is provided. For example, if a diet is lacking in oils or fats, vitamin A is not well absorbed and utilised. The immune systems become weak and illness is more common and more severe, increasing under-ﬁve death rates. The eye could be damaged with appearance of lesions, and when severe, blindness can occur. There is an increased risk of a woman dying during pregnancy or during the ﬁrst three months after delivery. Iodine is found naturally in topsoil, but in most areas of the country and especially the highlands, top soil has been lost due to deforestation, erosion and ﬂooding, and thus food crops lack iodine resulting in dietary iodine deﬁciency. Its direct causes can be broadly categorised as poor, insufﬁcient or abnormal red blood cell production, excessive red blood cell destruction, and excessive red blood cell loss. Contributing causes include poor nutrition related to dietary intake and dietary quality (iron deﬁciency in particular), infectious and parasitic diseases; inadequate sanitation and health behaviours; lack of access to health services; and poverty. The two major direct causes of anaemia, with excessive red cell destruction, are malaria and worm infections. Increase access to ﬁve, by one third by 2015 iodised salt among Supplement 70% of households up to 80% postpartum women with high doses of vitamin A within 45 days of delivery 7. The vitamin A intake of a breastfed child depends on the vitamin A status of the mother, the stage of lactation, and the quantity of breastmilk consumed.
Current efforts are working with a number of strains generic 100 mg kamagra polo free shipping, mostly H5 strains purchase 100mg kamagra polo visa, as this seems to be the most likely origin at the present time. The cells could be grown on microcarri- ers – glass beads – to enable high volume culture (Osterholm 2005). Attenuating the virulence of the virus is important, considering the increased mortality rate of the current highly pathogenic H5N1 avian influenza when it does enter hu- man hosts. While the H5N1 mortality rate in humans at present doesn’t neces- sarily reflect the mortality rate in an eventual pandemic, serious attention must be paid to the pathogenicity of the current H5N1 strain before it can be used in a vaccine. This may open even more doors for potential reassortment, however, and it may take considerable time to demonstrate safety in certain populations, such as the elderly and chil- dren. These vaccines will likely never be used, and are being developed to demonstrate that when the actual pandemic vaccine is needed, the principle is sound, and the technology is in place and proven on previous vaccines – hence the term “mock vaccine”. The important Pandemic Vaccine 141 aspect is the development of established vaccines that do not need lengthy studies before they can enter the market. They need to contain viral antigens humans have not had previous exposure to, such as the H5N1 antigens, and companies need to take them through clinical trials to determine immunogenicity, dose, and safety, and ultimately be licensed for use in the same stringent procedures used for other vac- cines. Currently, an expedited system is in place for the inactivated influenza vaccines against seasonal human influenza – the whole process, from the identification of the strains to be used, to the injection in the consultation room, takes about 6-8 months, because the vaccine is an established one, and only certain aspects need to be con- firmed prior to release. Production capacity In an ideal world, 12 billion doses of monovalent vaccine would be available in order to administer two doses of vaccine to every living human being. Currently, the world’s vaccine production capacity is for 300 million doses of tri- valent vaccine per year. This amounts to 900 million doses of monovalent vaccine, if all production were shifted to make a pandemic vaccine. Considering that at least two doses will be needed, the current capacity serves to provide for only 450 million people. This is further complicated by the fact that the dose of antigen that will be required is not yet known, but studies indicate that it may be higher than current human influenza vaccines (Fedson 2005). The world has suffered from vaccine shortages before – recently in the 2004/5 winter season, and closer to the threatening situation, in the pandemic of 1968. Furthermore, many countries do not have their own production facilities, and will rely on those countries that do. Transition Osterholm asks (Osterholm 2005), “What if the pandemic were to start …” – tonight – within a year – in ten years? The New England Journal of Medicine had an interview with Dr Osterholm, which is available online for listening to or for downloading: http://content. Vaccine and drug production would have to be escalated – for much later in the pandemic, as this will not make a difference in the short term. The world’s healthcare system would have to plan well in order to cope with distribu- tion when they become available – at present, it is doubted that it could handle the distribution and administration of the vaccines, never mind trying to handle that 142 Vaccines under the pressure placed on it by a pandemic. Vaccines may only be available for the second wave of the pandemic, which tends to have a higher mortality than the initial wave. If the pandemic starts in a year’s time, it is likely that we will then have some expe- rience in developing mock vaccines, so that a vaccine could be produced relatively quickly using a variety of the technologies currently under investigation. There would still be a significant delay, and it is likely that there would still be insufficient quantities, with rationing required. If the pandemic is delayed by a few years, we may well have the required vaccine production capacity to minimise the disastrous consequences. Strategies for expediting the development of a pandemic vaccine Shorten the time between emergence of a pandemic virus and the start of commer- cial production. This will require adopting a centralized evaluation team to examine the find- ings of the studies and give clearance for the use of the vaccine. The vaccine needs to become established through “mock” trials in order to be able to be expedited in this way – then, like the current influenza vaccine, it is known, and only brief studies are required to confirm immunogenicity and safety. Increased production capacity must be developed worldwide – for example, changing to cell culture vaccines. Another important means to improve pro- duction is to increase consumption – using more of the current vaccine today will not only decrease the burden of current influenza disease, as well as help- ing to prevent reassortment in humans infected with two strains of virus, but will ultimately enable production to be increased. Antigen sparing methods, such as intradermal injection, need to be researched more thoroughly, as they provide for a potential saving in antigen – the 1 µg of antigen (per strain) in current vaccines could be lowered considerably. If we th could use one 8 of the dose, our current 900 million monovalent doses could be expanded to 7. Adjuvants need to be evaluated – if immunogenicity can be enhanced, less an- tigen would be required for a protective immune response. Mock-up vaccines must be developed and tested in clinical trials to determine the most antigen sparing formulation and the best vaccination schedule (Fedson 2005, Kilbourne 2005). Controversies A number of controversies surrounding the development of a new influenza vaccine need to be dealt with (Fedson 2005, Osterholm 2005). Financial – patents exist for the plasmid-based methods of making virus in cell culture and the legal implications in various countries need to be examined and ad- dressed. Rationing – in the event of vaccine shortage, higher risk groups will need vaccina- tion first, along with those working on the front lines to control the pandemic. In such an event, the definition of “high risk group” may need to be revised – will it include children, for instance? Liability issues – due to increased vaccination with current vaccines, greater atten- tion must be paid to liability. Several countries have legislation that limits and/or covers certain liability for vaccine companies – encouraging such legislation will make vaccine companies feel more free to develop new vaccines, and increase the supply of current vaccines.
An increase in antigen load is clearly a participating factor buy 100mg kamagra polo fast delivery, as shown by the striking linkage of the Th1/Th2 balance to the dose after immunization with particulate antigens such as mycobacteria (Hernandez-Pando 1994) or Leshmania (Bretscher 1992) purchase 100mg kamagra polo mastercard. Indeed, Th1 cell apoptosis can partly be in- duced by foamy macrophages through a Fas/Fas ligand mechanism. Due to these properties, foamy macrophages are long-lived cells that harbor mycobacteria for long periods, and at the same time are a significant source of immunosuppress- ing cytokines that facilitate bacilli proliferation. When prosta- glandin production was suppressed in animals suffering from advanced disease, a significant reduction of pneumonia and bacillary load, with a striking increment in 5. Reactivation or progression of infection is sensitive to activation of the hypotha- lamic-pituitary adrenal axis. The exposure of humans to the stress of war or poverty (Spence 1993), or cattle to the stress of transportation, is efficient in causing reactivation of latent infection. In mice, it has been demonstrated that this is due to glucocorticoid release (corticosterone in mice) (Brown 1995, Tobach 1956), which reduces macrophage activation and Th1-cell activity (Daynes 1991), while syner- gizing with some Th2 functions (Rook 1994). Tuberculous patients lose the cir- cadian glucocorticoid rhythm, provoking constant exposure of peripheral lympho- cytes to cortisol (Sarma 1990). In addition, the total output of cortisol derivatives and of androgens is frequently reduced (Rook 1996). The lung enzyme 11-beta-hydroxysteroid dehydrogenase converts inactive cortisone to active cortisol, producing higher concentrations of cortisol in the tuberculous lung (Rook 2000). This factor induces adrenocorticotropic hormone production in the pituitary and in turn, this hormone stimulates the adrenals to produce glucocor- ticoid. The stimulus is so strong that both adrenals duplicate their weight due to nodular and diffuse hyperplasia (Hernandez-Pando 1995). In consequence, high concentrations of corticosterone are produced, contributing to the activation of Th2 cells and bacilli cell growth. Perhaps this immuno-endocrine response is another mechanism to avoid excess lung inflammation due to the well-known anti- inflammatory activity of glucocorticoids, but at the same time, this response con- tributes to deregulation of the protective immunity and bacilli growth. Interestingly, during experimental late progressive disease, a striking adrenal atrophy is produced (Hernandez-Pando 1995). Tuberculosis pathogenesis and pathology related to the immune response 181 in control animals (Zuckerman 1989, Bertini 1998). It is also im- portant to consider that the function of cortisol within lymphoid tissue is regulated by local production of the metabolites of dehydroepiandrosterone sulfate, an an- drogenic adrenal steroid that has “anti-glucocorticoid effects”, inducing strong activation of Th1 cells (Hernandez-Pando 1998). Administration of dehydroepian- drosterone or its derivative 3,17-androstenediol causes a Th1 bias, so this could be an efficient form of immunotherapy, as discussed below. As mentioned above, the vast majority never develop active disease (Bloom 1992), but in those persons that become sick, a wide spec- trum of possible clinical manifestations may occur, and the immune response, as seen for example in in vitro T- and B-cell reactivity against mycobacterial antigens, differs significantly from person to person. Thus, the clinical course of the infection and its epidemiological consequences depend on a complex interplay of host, envi- ronmental and bacterial factors (Nardell 1993, Hill 1998, Bellamy 1998, Stead 1992, Kramnik 2000). However, it seems that the independent participation of these genes is not sufficient to confer full protection against virulent M. As illustrated in this chapter, the host immune response against mycobacterial infection is the most investigated factor; but recent studies indicate that the genetic variability of M. Therefore, most of the immunological research has been done with a limited number of laboratory strains, including H37Rv or Erdman. This genetic variability is related to recent epidemi- ological data indicating striking differences in virulence and transmissibility (Val- way 1998, Caminero 2001). Particular outbreak strains were found to elicit distinct immune paths and mortality rates in the course of experimental infection. The clinical and epidemiological differences in this strain have there- fore now been linked with immunological and genetic differences (McShane 2003). This study demonstrated marked differences in virulence, cytokine induc- tion and immunopathology among the different strains. This is important, considering that the Beijing genotype is the predominant strain in several distinct geographical areas, presumably due to a selective advantage over other strains (van Soolingen 1995). Latency and maintenance of the immune response 183 using different clinical isolates and mutant strains are necessary to evaluate how the genetic differences translate into functional differences. The initial infection usually occurs in the lungs and in most cases is controlled by the immune system. These types of immune responses, of which the tuberculin skin test is a conspicuous exponent, is also crucial for protection in latently infected individuals. Interestingly, in the mouse model of latent infection, we occasionally observed intracytoplasmic bacilli in bronchial cells and type 2 pneumocytes, suggesting that, as happens in vitro (Bermudez 1996), mycobacteria can also infect the lung epithelium during experimental latent infection, but in a microenvironment that is completely different from that found in 184 Immunology, Pathogenesis, Virulence chronic granulomas. It is also important to consider that epithelial cells have a short life span, thus the maintenance of latent bacilli in this cell type should be different from those located in chronic granulomas. In those cases, it is likely that the growth of the bacilli re- sumes directly from the reactivation site rather than from pulmonary sites. Animal work suggests that it might be possible to potentiate the immune system to destroy the organisms more efficiently and even to eliminate bacilli that persist in latently infected tissues. As mentioned before, the injection of culture fil- trate led to necrotic reactions, both at the site of injection and in distant lesions, and was abandoned (Anderson 1891). However, during the last decade, several studies have demonstrated striking therapeutic effects in experimental animal models by 5. In general, two approaches have been used: the first one consists of direct stimulation of the Th1 response; and the second aims at the inactivation of factors that suppress the cellular immune response, which are also, usually natural anti-inflammatory factors. Both compounds were protec- tive, particularly 3β,17β androstenediol, which caused reduction in bacterial counts and prolonged survival. Transfer factors or leukocyte dialyzates are subcellular leukocyte components that appear to be able to transmit information for specific immune responses from expe- rienced or memory leukocytes to naïve leukocytes (Lawrence 1955).
The upside to immunity discount kamagra polo 100 mg on-line, however cheap kamagra polo 100 mg overnight delivery, is so much greater: The benefit of staying alive far outweighs the negatives caused when the system does sometimes go awry. Therefore, the immune system is required to interact with other organ systems, sometimes in complex ways. Thirty years of research focusing on the connections between the immune system, the central nervous system, and the endocrine system have led to a new science with the unwieldy name of called psychoneuroimmunology. The physical connections between these systems have been known for centuries: All primary and secondary organs are connected to sympathetic nerves. What is more complex, though, is the interaction of neurotransmitters, hormones, cytokines, and other soluble signaling molecules, and the mechanism of “crosstalk” between the systems. For example, white blood cells, including lymphocytes and phagocytes, have receptors for various neurotransmitters released by associated neurons. Additionally, hormones such as cortisol (naturally produced by the adrenal cortex) and prednisone (synthetic) are well known for their abilities to suppress T cell immune mechanisms, hence, their prominent use in medicine as long-term, anti-inflammatory drugs. One well-established interaction of the immune, nervous, and endocrine systems is the effect of stress on immune health. In the human vertebrate evolutionary past, stress was associated with the fight-or-flight response, largely mediated by the central nervous system and the adrenal medulla. The physical action of fighting or running, whichever the animal decides, usually resolves the problem in one way or another. On the other hand, there are no physical actions to resolve most modern day stresses, including short-term stressors like taking examinations and long-term stressors such as being unemployed or losing a spouse. The effect of stress can be felt by nearly every organ system, and the immune system is no exception (Table 21. Effects of Stress on Body Systems System Stress-related illness Integumentary system Acne, skin rashes, irritation Headaches, depression, anxiety, irritability, loss of appetite, lack of motivation, Nervous system reduced mental performance Muscular and skeletal Muscle and joint pain, neck and shoulder pain systems Circulatory system Increased heart rate, hypertension, increased probability of heart attacks Indigestion, heartburn, stomach pain, nausea, diarrhea, constipation, weight gain Digestive system or loss Immune system Depressed ability to fight infections Male reproductive Lowered sperm production, impotence, reduced sexual desire system Female reproductive Irregular menstrual cycle, reduced sexual desire system Table 21. First, most short-term stress does not impair the immune system in healthy individuals enough to lead to a greater incidence of diseases. However, older individuals and those with suppressed immune responses due to disease or immunosuppressive drugs may respond even to short-term stressors by getting sicker more often. It has been found that short-term stress diverts the body’s resources towards enhancing innate immune responses, which have the ability to act fast and would seem to help the body prepare better for possible This OpenStax book is available for free at http://cnx. The diverting of resources away from the adaptive immune response, however, causes its own share of problems in fighting disease. Chronic stress, unlike short-term stress, may inhibit immune responses even in otherwise healthy adults. The suppression of both innate and adaptive immune responses is clearly associated with increases in some diseases, as seen when individuals lose a spouse or have other long-term stresses, such as taking care of a spouse with a fatal disease or dementia. The new science of psychoneuroimmunology, while still in its relative infancy, has great potential to make exciting advances in our understanding of how the nervous, endocrine, and immune systems have evolved together and communicate with each other. Primary lymphoid organs, the bone marrow and thymus gland, are the locations where lymphocytes of the adaptive immune system proliferate and mature. Many immune system cells use the lymphatic and circulatory systems for transport throughout the body to search for and then protect against pathogens. Whereas barrier defenses are the body’s first line of physical defense against pathogens, innate immune responses are the first line of physiological defense. Innate responses occur rapidly, but with less specificity and effectiveness than the adaptive immune response. Innate responses can be caused by a variety of cells, mediators, and antibacterial proteins such as complement. Within the first few days of an infection, another series of antibacterial proteins are induced, each with activities against certain bacteria, including opsonization of certain species. They do not recognize self-antigens, however, but only processed antigen presented on their surfaces in a binding groove of a major histocompatibility complex molecule. There are several functional types of T lymphocytes, the major ones being helper, regulatory, and cytotoxic T cells. B cells have their own mechanisms for tolerance, but in peripheral tolerance, the B cells that leave the bone marrow remain inactive due to T cell tolerance. Some B cells do not need T cell cytokines to make antibody, and they bypass this need by the crosslinking of their surface immunoglobulin by repeated carbohydrate residues found in the cell walls of many bacterial species. The components of the immune response that have the maximum effectiveness against a pathogen are often associated with the class of pathogen involved. Bacteria and fungi are especially susceptible to damage by complement proteins, whereas viruses are taken care of by interferons and cytotoxic T cells. Pathogens have shown the ability, however, to evade the body’s immune responses, some leading to chronic infections or even death. Over-reactive immune responses include the hypersensitivities: B cell- and T cell-mediated immune responses designed to control pathogens, but that lead to symptoms or medical complications. The worst cases of over- reactive immune responses are autoimmune diseases, where an individual’s immune system attacks his or her own body because of the breakdown of immunological tolerance. These diseases are more common in the aged, so treating them will be a challenge in the future as the aged population in the world increases. Blood needs to be typed so that natural antibodies against mismatched blood will not destroy it, causing more harm than good to the recipient. Although this has been shown to occur with some rare cancers and those caused by known viruses, the normal immune response to most cancers is not sufficient to control cancer growth. Thus, cancer vaccines designed to enhance these immune responses show promise for certain types of cancer. What are the three main components of the lymphatic Phagocyte chemotaxis is the movement of phagocytes system?
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