By X. Hengley. United States Military Academy. 2019.
Every researcher has to provide sound scientific reasons for using animals adalat 20mg free shipping, explaining why no realistic alternative exists generic adalat 30 mg mastercard. For the future, we expect that the rapid pace of change in medical research will continue to change the sorts of animal studies we do. As we turn to genetics more and more for clues to understand disease, the importance of research on mice will continue to grow. Some people argue passionately that no animals should ever be used in any research. Others, perhaps the silent majority, accept the process is necessary if the cures and treatments of tomorrow are to be found. We are still a long way from understanding fully how complex living creatures develop correctly, stay healthy, and why disease occurs. Campaigners against animal research argue that the differences between species are so great that information from animals cannot be reliably translated in humans. It is true that data from animal work have to be interpreted with caution but the similarities between species are much greater than the differences. Studying disease patterns in animals as well as their reactions to possible treatments provides powerful clues about what is happening in the human body. The genes that control the basic functions of human cells are often similar to those in very simple creatures, and in the mouse,there are counterparts for nearly every human gene. It is sometimes asked why living animals have to be used to understand the causes of illness, or to find new medicines, when we have ways of analysing cells and tissues. A whole body be it a mouse or a human is a vastly more complicated biological engine than just a few constituent parts. For instance,a diseased liver on its own would not reveal how that illness affected the immune system. Where possible cell cultures, tissue cultures, computers and lower organisms such as bacteria or plants are used as alternatives to animal work,usually in the preliminary stages of research. Cell and tissue cultures The study of living cells maintained outside the body in a glass or plastic container is known as in vitro (in glass) examination. Tissue cultures, taking thin sections of organs like liver and kidney, or encouraging several types of cells to grow together the way they would in nature,can be used to study the possible effects of drugs on these organs. However, they are difficult to maintain,have a limited life span and cannot give wider information for example about possible effects in other parts of the body, or how other parts of the body affect the tissues being studied. Organisms such as invertebrates, plants, micro-organisms and chicken eggs are used to provide early information on biological systems, and how these respond to potential treatments. This is not only providing new information on the activity of chemicals in the living brain,but also means that fewer rats and mice need to be killed. Computers Computers and mathematical modelling to predict biological activity have revolutionised the process of drug discovery by reducing the need to use animals for the very early pre- screening of possibly millions of potential drug candidates. But all computer techniques depend crucially on what information is fed into the computer, and much about the detailed workings of the body are still not known. Computers can only make predictions from previous animal, test-tube and human studies so although we can make better use of the knowledge we still depend on the original data from animals on which to base predictions. Moreover, computers cannot predict how a medicine might react in a complex living system,or whether unexpected side- effects might show up. Powerful asthma drugs and effective anti-depressant drugs owe their origins to animal work. Vaccines against distemper, once a major killer of dogs, and vaccines for cats against feline leukaemia virus, were developed through animal work. The effectiveness of penicillin, which revolutionised the treatment of bacterial infection, was proved in tests on mice. Polio epidemics, which until the 1950s killed and paralysed millions of children, were consigned to history in most parts of the world by vaccines which resulted directly from work on a range of laboratory animals, including monkeys. Blood transfusion, without which much major surgery is impossible,became a reality in 1915 after work on dogs. Major heart surgery such as bypass techniques and heart transplants were developed in the 1960s through work on dogs and pigs. Kidney dialysis, which sustains the life of thousands of people if they are unable to receive kidney transplants, came about through work on rabbits and dogs. The drug heparin, to stop blood clotting during kidney dialysis and after surgery, was discovered in dogs and is still obtained from the liver and lungs of cows. Future treatments for multiple sclerosis, cystic fibrosis, spinal cord injury, Alzheimer s disease and a range of other conditions are being investigated with the help of animal studies. The questions being tackled,and the methods being used,are very different from those used 30 years ago. H oweve r, t h e re is still much t h at is not k n own about h ow the disease develops from t h i s d e fe ct, or what can be done to reverse the pro ce s s. Nor is it well understood why the disease d evelops in diffe re nt ways in d i ffe re nt p at i e nt s. This has Children with cystic fibrosis a l l owed detailed study of what need regular physiotherapy to a ctually goes wrong in the lungs clear their lungs. We now k n ow this includes a fa i l u re to clear t wo import a nt lung ge r m s, k n own as S t a p hy l o coccus aure u s and Burkholderia (Ps e u d o m o n a s).
As we said earlier purchase 20mg adalat mastercard, these diseases are associated with overcrowding and insanitary conditions in other words cheap 30 mg adalat amex, they are associated with poverty. They are best prevented by addressing the underlying socioeconomic circumstances that promote louse infestation: overcrowding, poverty, homelessness and population displacement. However, you should also educate people in your community to take the following preventive actions:. Change clothes and bedding at frequent intervals to reduce the number of body lice. Treat louse-infested clothes and bedding with chemicals to kill the lice and their eggs (this is called delousing). In infested situations like those in refugee camps, clothes and bedding should be deloused by trained personnel with appropriate insecticides, such as 0. Treating clothing with liquid permethrin can provide long-term protection against louse infestation. Note that close contact with patients should be avoided and delousing of the patient s clothes and bedding should be done immediately, to prevent transmission of infected body lice from the patient to healthy people including the health workers who are caring for them. If there is an outbreak of relapsing fever or typhus, the spread of infection can be controlled by active case nding and effective treatment of infected persons and their close contacts with the correct antibiotics. Early treatment controls the spread of infection by reducing the reservoir of bacteria in the local population. In the next study session, we complete the discussion of vector-borne diseases by describing four that are of signicant public health importance in Ethiopia. They are vector-borne febrile illnesses caused by bacteria and transmitted by the human body louse. What educational messages do you give the families in that village and what is your health education aiming to prevent? A It is possible to distinguish between relapsing fever and typhus at Health Post level by identifying differences in their symptoms. C Treatment with the correct antibiotics is sufcient to control epidemics caused by relapsing fever or typhus. D The correct antibiotics can effectively treat relapsing fever and typhus if the patient is referred immediately. E Health workers should protect themselves from developing relapsing fever or typhus by avoiding close contact with patients with these diseases. A better understanding of these diseases will help you to identify patients and refer them quickly to a health centre or hospital for specialist treatment. You will also learn about the health education messages that you need to communicate to members of your community, so they can reduce their exposure to the vectors of these diseases and apply appropriate prevention measures. As you will see in this study session, prevention of all of these diseases includes controlling the vectors with chemicals and/or environmental management, using personal protective clothing or bed nets to reduce exposure to the vectors, and rapid case detection and referral for treatment. Early treatment prevents serious complications and can save lives, and it also reduces the reservoir of infectious agents in the human population. Learning Outcomes for Study Session 37 When you have studied this session, you should be able to: 37. In some described as chronic because the symptoms develop gradually, places, the disease is known by its alternative name bilharzia. Approximately 200,000 people die every year in Africa as a result of the complications caused by these parasites. Rural communities living near water bodies such as rivers, lakes and dams may be highly affected by the disease, because the worms have a complex lifecycle in which they spend part of their development living in freshwater snails. First, as a Health Extension Practitioner, you need to know where the disease is common in Ethiopia. Schistosoma mansoni is widespread in several parts of Ethiopia, usually at an altitude of between 1,200 to 2,000 metres above sea level. In many of these locations, more than 60% of schoolchildren are infected with Schistosoma mansoni. A high burden of the disease in children has severe adverse effects on their growth and performance at school. Washing, swimming or standing in infected water exposes people to the risk of infection with Schistosoma parasites. The major reservoirs of Schistosoma parasites are infected humans (the primary hosts) and freshwater snails (the intermediate hosts). The eggs pass out into the water in either the faeces or urine, to continue the infection cycle. The immune reaction causes an acute inammation around the eggs, which can lead to chronic symptoms (see Box 37.
Cephalosporins provide good clearance of nasal carriage in the patient generic adalat 20 mg on line, but penicillins do not cheap adalat 20mg with amex. Poor givenstill demonstrates the causative organism in many prognostic markers include hypotension, confusion and cases. Abroad-spectrum antibiotic such as a cephalosporin at high doses is initially recommended due to the increasing emergence of penicillin-resistant strepto- Viral meningitis cocci. Once cultures and sensitivities are available, the course and choice of agent can be determined Denition (ceftriaxone/cefotaxime for Haemophilus inuenzae Acute viral infection of the meninges is the most com- andStreptococcuspneumoniae,penicillinforN. Aetiology Pathophysiology Mayarise as a complication of miliary tuberculosis or In viralmeningitis there is a predominantly lymphoid in primary or post primary infections. Ifatuberculous focus develops in the brain, meninges or Rash, upper respiratory symptoms and occasionally di- skull and ruptures into the subarachnoid space, a hyper- arrhoeamaybepresent. This inammation can directly involve the cranial are absent in recurrent infections. Clinical features Culture is possible, but rarely useful clinically as it The onset is usually insidious over days or weeks, al- takes up to 2 weeks. Focal neurology may develop If bacterial meningitis is suspected, broad-spectrum an- at this time including cranial nerve signs and hemi- tibiotics must be given without delay. Macroscopy/microscopy The subarachnoid space is lled with a viscous green exudate, the meninges are thickened and tubercles and Tuberculous meningitis chronic inammation may be seen in the brain and on Denition the meninges. Treatment Metastatic carcinoma and should be initiated on clinical suspicion, before conr- adenocarcinomas mation, as deterioration can occur within days, and even Auto-immune/ Systemic lupus erythematosus Inammatory Behcet s disease when treated mortality is as high as 15 40%. Sarcoid Corticosteroids have been shown to reduce vascular Drugs Particularly nonsteroidal complications, and improve survival and neurological anti-inammatory drugs function. If it is not clear whether the process is bacterial or vi- Aetiology ral, antibiotics may be given empirically whilst awaiting The differential diagnosis for these cases of aseptic further investigation. Acute viral encephalitis Investigations/management In many cases of aseptic meningitis, the diagnosis is of Denition aself-limiting, benign viral meningitis. However, it is Inammation of the brain parenchyma caused by important to consider these other causes, particularly if viruses. Around the world, arthropod- In all cases except herpes simplex encephalitis there is borne viruses cause epidemics and rabies causes an no effective treatment apart from supportive manage- almost invariably fatal encephalitis. Sus- pected cases of herpes encephalitis are treated urgently Pathophysiology with high dose i. Inammation affects the meninges and parenchyma causing oedema and hence Prognosis raised intracranial pressure, diffuse and focal neurolog- Herpes simplex encephalitis has a mortality of 20% de- ical dysfunction. Seizures (par- ticularly temporal lobe seizures) are also a presenting Tetanus feature. Denition Tetanus is a toxin mediated condition causing muscle Macroscopy/microscopy spasms following a wound infection. The meninges are hyperaemic, the brain is swollen, sometimes with evidence of petechial haemorrhage and necrosis. There is cufng of blood vessels by mononu- Aetiology clear cells and viral inclusion bodies may be seen. Clostridium tetani (the causative organism), an anaero- bic spore forming bacillus, originates from the faeces of domestic animals. Tracheostomy and ventilatory support may r Generalisedtetanusisthemostcommonpresentation, be necessary for severe laryngeal spasm. The Childrenareroutinelyvaccinatedagainsttetanusfrom facial muscles may contort to cause a typical expres- age 2 months. Any sensory stimulation such asnoiseresultsingeneralisedmusclespasmsincluding Poliomyelitis arching of the back (opisthotonos). Spasms of the lar- ynx can impede respiration, and autonomic dysfunc- Denition tion causes arrhythmias, sweating and a labile blood Infection of a susceptible individual with poliovirus type pressure. Geography Acute poliomyelitis has been eradicated in developed Complications countries, apart from rare cases due to the live, atten- Muscle spasms may lead to injury, in severe cases res- uated oral polio vaccine. Thevirusisneurotropic,withpropensityfortheanterior r A booster dose with tetanus toxoid (which is an in- horn cells of the spinal cord and cranial nerve motor activated toxin which induces active immunisation), neurones. The virus enters via the gastrointestinal tract, or course of three injections, should additionally be then migrates up peripheral nerves. Theincubationperiodis7 14days,anumberofpatterns Active tetanus:Patients should be nursed in a quiet, occur: dark area to reduce spasms. Surgical wound debride- r Subclinical infection occurs in 95% of infected indi- ment should be performed where indicated and intra- viduals. However, the immunoglobulin can only neu- r Paralytic poliomyelitis occurs in about 0.
Minimal radiologic changes are common in many cases of sterile sinusitis as well as in asymptomatic individuals proven 20 mg adalat. Such information is essential for assessing the need for surgical intervention in the treatment of chronic sinusitis order 30 mg adalat fast delivery. A coronal section exhibits significant sinus disease on the left with a relatively normal appearance on the right. Complications In the age of antibiotics, severe life-threatening complications of acute sinusitis are relatively uncommon. However, the clinician must be able to recognize clinical manifestations of potentially fatal complications of sinusitis so that prompt medical and surgical treatments can be initiated in a timely fashion. Symptoms commonly associated with acute frontal sinusitis include frontal pain, local erythema and swelling, fever, and purulent nasal discharge. Serious complications of frontal sinusitis may be attributed to the proximity of the frontal sinus to the roof of the orbit and anterior cranial fossa. Osteomyelitis can result from acute frontal sinusitis and may present as a localized subperiosteal abscess (Pott puffy tumor). Sinus radiographs exhibit sclerotic changes in the bone contiguous to the frontal sinus. Intracranial complications of frontal sinusitis include extradural, subdural, and brain abscesses as well as meningitis and cavernous sinus thrombosis (57). Extension of inflammation into the orbit can result in unilateral orbital and periorbital swelling with cellulitis. This presentation can be distinguished from cavernous sinus thrombosis by the lack of focal cranial neurologic deficits, absence of retroorbital pain, and no meningeal signs. Affected patients usually respond to antibiotics, and surgical drainage is rarely necessary. Cavernous sinus thrombosis is a complication of acute or chronic sinusitis, which demands immediate diagnosis and treatment ( 57). The cavernous sinuses communicate with the venous channels draining the middle one third of the face. Cavernous sinus thrombosis often arises from a primary infection in the face or paranasal sinuses. Vital structures that course through the cavernous sinus include the internal carotid artery and the third, fourth, fifth, and sixth cranial nerves. Symptoms of venous outflow obstruction caused by cavernous sinus thrombosis include retinal engorgement, retrobulbar pain, and visual loss. Impingement of cranial nerves in the cavernous sinus can result in extraocular muscle paralysis and trigeminal sensory loss. If not treated promptly with high doses of parenteral antibiotics, septicemia and central nervous system involvement lead to a fatal outcome. Affected patients report occipital and retroorbital pain, or the pain distribution may be nonspecific. Because of the posterior location of the sphenoid sinus, diagnosis of sphenoiditis may be delayed until serious complications are recognized. It long has been recognized that chronic or recurrent sinusitis may exacerbate asthma. Successful prevention and treatment of chronic sinusitis can be effective in controlling patients with difficult or refractory asthma. Slavin ( 58) described a group of steroid-dependent asthmatics with sinusitis in whom sinus surgery (i. Asthma symptoms, steroid requirements, and nonspecific airway reactivity were reduced after surgery. The primary goal of treatment should be facilitation of drainage of affected sinuses and elimination of causative organisms. These data suggest that antibiotics are being used unnecessarily in many patients who could also have viral infections. Judicious use of antibiotics is essential, especially in light of increasing problems with antibiotic resistance. Oral decongestants alone or combined with antihistamines may diminish nasal mucosal edema and enhance sinus drainage. A 12-hour sustained-release oral preparation containing pseudoephedrine or phenylpropanolamine combined with antibiotics is recommended. Frequent nasal lavage with saline can be effective for improvement of sinus drainage. Intranasal glucocorticoids may be a useful adjunctive treatment for decreasing mucosal inflammation and edema. Antibiotics should be considered in those who fail the aforementioned drainage measures. For treating acute sinusitis, amoxicillin (250 500 mg three times daily) is still the antibiotic of choice.