By L. Sigmor. University of Pennsylvania. 2019.
Countries with production facilities should support and ensure by all means that rapid and large-scale production can take place during a pandemic cheap 30 gm elimite visa. In some devel- oped nations buy cheap elimite 30gm line, the government considers it to be its responsibility to provide the highest possible protection at the onset of a pandemic. For example, the Dutch gov- ernment is currently negotiating with a manufacturer to ensure that a vaccine against any future pandemic influenza strain is available in the Netherlands as soon as possible following its development (van Dalen 2005). Plans for pandemic vaccine use should include: designation of mass immunisation clinics, strategies for staffing and staff training, strategies to limit distribution to persons in the priority groups, vaccine storage capacity of the cold chain, identifi- cation of current and potential contingency depots, vaccine security (theft preven- tion) during its transport, storage and use in clinics. Antiviral Drugs Antiviral drugs include M2 inhibitors, which are ion channel blockers (amantadine and rimantadine), and the neuraminidase inhibitors (oseltamivir and zanamivir) (Hoffmann 2006b). Treatment with M2 inhibitors can cause emergence of fully pathogenic and transmissible resistant variants in at least 30 % of individuals (Hay- den 1997). After treatment with neuraminidase inhibitors, resistant variants were initially found in approximately 4 % to 8 % of children and < 1 % of adults (McKimm-Breschkin 2003, Stilianakis 2002), and were identified later in 18 % of Japanese children dur- ing treatment with oseltamivir (Kiso 2004). The emergence of resistant influenza A (H5N1) variants during oseltamivir treatment was recently reported in two Viet- namese patients (de Jong 2005). Influenza A (H5N1) viruses with a H274Y substi- tution in the neuraminidase gene, which confers high-level resistance to oseltamivir (Gubareva 2001), were isolated from both patients. Even though oseltamivir was administered at the recommended dose and duration (75 mg twice daily for five days, with a weight-based reduction in the dose for children less than 13 years old) and treatment was started when the greatest clinical benefit could be expected (within 48 hours after the onset of symptoms), both patients died. These observa- tions suggest that the development of drug resistance contributed to the failure of therapy in these patients. New routes of administration of antivirals should also be explored, as altered phar- macokinetics in severely ill influenza patients, who may be affected by diarrhoea, have been reported (Hien 2004). There are concerns that young children and patients with intellectual or co- ordination impairments are not able to inhale zanamivir properly (Imuta 2003). However, as resistance against oseltamivir can emerge during the currently recom- mended regimen, and as zanamivir might be less prone to the development of re- sistance mutations (Moscona 2005), zanamivir might be included in the treatment arsenal for influenza A (H5N1) virus infections. The number of courses of oseltamivir to be stockpiled by each country depends on existing re- sources and population size. The World Health Organisation has been urging coun- tries to stockpile the drug in advance (Abbott 2005). For example, the Dutch gov- ernment has stockpiled approximately 225,000 courses of oseltamivir (Groeneveld 2005). The cost benefit of stockpiling and the optimal strategy for antiviral use were re- cently investigated for the Israeli population by using data (numbers of illness epi- sodes, physician visits, hospitalisations, and deaths) derived from previous influ- 116 Pandemic Preparedness enza pandemics. Costs to the healthcare system and overall costs to the economy, the latter including the value of lost workdays but not the potential value of lost lives, were calculated (Balicer 2005). Three strategies for the use of oseltamivir during a pandemic were defined: therapeutic use, long-term pre-exposure prophy- laxis, and short-term postexposure prophylaxis for close contacts of influenza pa- tients (with index patients under treatment). The first two strategies could target either the entire population or only those at high risk of complications. The most favourable cost-benefit ratio was found when stockpiled antiviral drugs were ad- ministered either solely as a therapeutic measure or as a short-term prophylaxis for exposed contacts, a strategy termed “targeted prophylaxis” (Longini 2004). Therefore, in developing countries targeted prophylaxis is particularly important for saving resources. While in most developing countries the use of antiviral agents is not expected, in developed nations the use of antiviral agents depends on whether the drugs are in short or large supply (see Table 3). When the pandemic first reaches the Netherlands Treat Provide prophylaxis to a Index patients Families, housemates and other contacts of index patients: post-exposure prophylaxis 2. In a manifest pandemic or in the event of large-scale virus introduction from abroad If neuraminidase Treat inhibitors are in b c Risk groups , professionals , and short supply (when relevant) people in pan- a demic-specific risk group ; other- wise healthy people: in the event of hospitalisation due to complications If neuraminidase Treat Provide prophylaxis to d inhibitors are not in Patients displaying symptoms con- Individual patients and risk short supply sistent with influenza groups, professionals, and (where relevant) people in pandemic-specific risk e group a. As soon as possible following the appearance of the first symptoms; if treatment is not started within 48 hours, it may not be effective. Patients with serious respiratory, pulmonary or cardiovascular abnormalities or dysfunction, who, if infected with the pandemic influenza virus, would be at serious risk of pulmonary or cardiovascular function decompensation, patients with an insulin-dependent form of diabetes. All persons responsible for the diagnosis, treatment and care of influenza patients, or for logistic management of the necessary resources. Inter-Pandemic Period and Pandemic Alert Period 117 Personal stockpiling of oseltamivir is strongly discouraged (Brett 2005, Moscona 2005) as this would likely lead to the use of insufficient doses or inadequate courses of therapy, and thus facilitate the emergence of oseltamivir-resistant variants. Moreover, personal stockpiling of oseltamivir further depletes the current supply that is already inadequate to meet the demand. Antibiotics should be stockpiled for the treatment of Staphylococcus aureus and other secondary infections by each hospital. General Measures Non-medical interventions have been shown to be relevant for controlling emergent infectious diseases. In Thailand, community participation at different levels was considered in the national program against H5N1 avian influenza.
In addition generic elimite 30gm online, accessory muscles (primarily the internal intercostals) help to compress the rib cage order elimite 30gm visa, which also reduces the volume of the thoracic cavity. Respiratory Volumes and Capacities Respiratory volume is the term used for various volumes of air moved by or associated with the lungs at a given point in the respiratory cycle. There are four major types of respiratory volumes: tidal, residual, inspiratory reserve, and expiratory reserve (Figure 22. Respiratory volume is dependent on a variety of factors, and measuring the different types of respiratory volumes can provide important clues about a person’s respiratory health (Figure 22. Explain how spirometry test results can be used to diagnose respiratory diseases or determine the effectiveness of disease treatment. In addition to the air that creates respiratory volumes, the respiratory system also contains anatomical dead space, which is air that is present in the airway that never reaches the alveoli and therefore never participates in gas exchange. Alveolar dead space involves air found within alveoli that are unable to function, such as those affected by disease or abnormal 1054 Chapter 22 | The Respiratory System blood flow. Total dead space is the anatomical dead space and alveolar dead space together, and represents all of the air in the respiratory system that is not being used in the gas exchange process. Respiratory Rate and Control of Ventilation Breathing usually occurs without thought, although at times you can consciously control it, such as when you swim under water, sing a song, or blow bubbles. Respiratory rate can be an important indicator of disease, as the rate may increase or decrease during an illness or in a disease condition. The respiratory rate is controlled by the respiratory center located within the medulla oblongata in the brain, which responds primarily to changes in carbon dioxide, oxygen, and pH levels in the blood. A child under 1 year of age has a normal respiratory rate between 30 and 60 breaths per minute, but by the time a child is about 10 years old, the normal rate is closer to 18 to 30. By adolescence, the normal respiratory rate is similar to that of adults, 12 to 18 breaths per minute. Ventilation Control Centers The control of ventilation is a complex interplay of multiple regions in the brain that signal the muscles used in pulmonary ventilation to contract (Table 22. The result is typically a rhythmic, consistent ventilation rate that provides the body with sufficient amounts of oxygen, while adequately removing carbon dioxide. The major brain centers involved in pulmonary ventilation are the medulla oblongata and the pontine respiratory group (Figure 22. The second respiratory center of the brain is located within the pons, called the pontine respiratory group, and consists of the apneustic and pneumotaxic centers. Factors That Affect the Rate and Depth of Respiration The respiratory rate and the depth of inspiration are regulated by the medulla oblongata and pons; however, these regions of the brain do so in response to systemic stimuli. It is a dose-response, negative-feedback relationship in which the greater 1056 Chapter 22 | The Respiratory System the stimulus, the greater the response. The major factor that stimulates the medulla oblongata and pons to produce respiration is surprisingly not oxygen concentration, but rather the concentration of carbon dioxide in the blood. A central chemoreceptor is one of the specialized receptors that are located in the brain and brainstem, whereas a peripheral chemoreceptor is one of the specialized receptors located in the carotid arteries and aortic arch. Concentration changes in certain substances, such as carbon dioxide or hydrogen ions, stimulate these receptors, which in turn signal the respiration centers of the brain. As will be explained in more detail later, increased carbon dioxide levels lead to increased levels of hydrogen ions, decreasing pH. The increase in hydrogen ions in the brain triggers the central chemoreceptors to stimulate the respiratory centers to initiate contraction of the diaphragm and intercostal muscles. As a result, the rate and depth of respiration increase, allowing more carbon dioxide to be expelled, which brings more air into and out of the lungs promoting a reduction in the blood levels of carbon dioxide, and therefore hydrogen ions, in the blood. In contrast, low levels of carbon dioxide in the blood cause low levels of hydrogen ions in the brain, leading to a decrease in the rate and depth of pulmonary ventilation, producing shallow, slow breathing. Another factor involved in influencing the respiratory activity of the brain is systemic arterial concentrations of hydrogen + ions. Increasing carbon dioxide levels can lead to increased H levels, as mentioned above, as well as other metabolic activities, such as lactic acid accumulation after strenuous exercise. Peripheral chemoreceptors of the aortic arch and carotid arteries sense arterial levels of hydrogen ions. When peripheral chemoreceptors sense decreasing, or more acidic, pH levels, they stimulate an increase in ventilation to remove carbon dioxide from the blood at a quicker rate. If blood oxygen levels become quite low—about 60 mm Hg or less—then peripheral chemoreceptors stimulate an increase in respiratory activity. The chemoreceptors are only able to sense dissolved oxygen molecules, not the oxygen that is bound to hemoglobin. As you recall, the majority of oxygen is bound by hemoglobin; when dissolved levels of oxygen drop, hemoglobin releases oxygen.
The glycolytic pathway is common to virtually all organisms Both eukaryotes and prokaryotes In eukaryotes generic elimite 30gm with visa, it occurs in the cytosol 7 1 cheap elimite 30 gm on-line. Glyceraldehyde 3-Phosphate Dehydrogenase Energy transformation: Phosphorylation is coupled to the oxidation of glyceraldehyde 3-phosphate. Glyceraldehyde 3-Phosphate Dehydrogenase Energy transformation: Phosphorylation is coupled to the oxidation of glyceraldehyde 3-phosphate. Glyceraldehyde 3-Phosphate Dehydrogenase The enzyme-bound thioester intermediate reduces the activation energy for the second reaction: 24 1. Phosphoglycerate Mutase The next two reactions convert the remaining phosphate ester into a phosphate having a high phosphoryl transfer potential The first is an isomerization reaction 26 1. Enolase The next two reactions convert the remaining phosphate ester into a phosphate having a high phosphoryl transfer potential The second is a dehydration (lyase) reaction 27 1. Maintaining Redox Balance The solution to this problem lies in what happens to the pyruvate that is produced in glycolysis: Fermentation Pathways 32 1. Maintaining Redox Balance Lactic acid fermentation is use by bacteria and human muscles and produces lactate. Usually due to loss of uridyl transferase activity Symptoms include Failure to thrive infants Enlarged liver and jaundice, sometimes cirrhosis Cataracts Mental retardation 41 2. Control of Glycolysis In metabolic pathways, control is focused on those steps in the pathway that are irreversible. Control of Glycolysis The different levels of control have different response times: Level of Control Response Time Allosteric milleseconds Phosphorylation seconds Transcriptional hours 44 2. Fructose 2,6-bisphosphate A regulated bifunctional enzyme synthesizes and degrades fructose 2,6-bisphosphate: 49 2. The brain has a strong preference for glucose, while the red blood cells have and absolute requirement for glucose. Gluconeogenesis The three kinase reactions are the ones with the greatest positive free energies in the reverse directions 54 3. Gluconeogenesis The hexokinase and phosphofructokinase reactions can be reversed simply with a phosphatase 55 3. Formation of Phosphoenopyruvate The conversion of pyruvate into phosphoenolpyruvate begins with the formation of oxaloacetate. Oxaloacetate Shuttle Oxaloacetate is synthesized in the mitochondria and is shuttled into the cytosol where it is converted into phosphoenolpyruvate 60 3. Regulation of Glycolysis and Gluconeogenesis Reciprocal regulation of glycolysis and gluconeogenesis in the liver 62 4. Evolution of Glycolysis and Gluconeogenesis Glycolysis and Gluconeogenesis are evolutionarily intertwined. Therapy for Anaphylactoid Reactions Bronchosapsm Minor-Uticaria, with or Oxygen without Skin Itching Mild- albuterol inhaler, 2 puffs No therapy Moderate-Epinephrine 0. Patients with prior evidence of an anaphylactoid reaction to contrast media should receive appropriate steroid and antihistamine prophylaxis prior to repeat contrast administration. In patients with prior history of allergic reactions to shellfish or seafood, anaphylactoid prophylaxis for contrast reaction is not beneficial. Patients undergoing cardiac catheterization with contrast media should receive adequate preparatory hydration. In patients with chronic kidney disease (creatinine clearance <60cc/min), the volume of contrast media should be minimized. Patient Total Air Kerma at the Interventional Reference Point (K , a,r Dose Gy) is the x-ray energy delivered to air 15cm from for patient dose burden Assessment for deterministic skin effects. The Procedure/Patient As patient size increases… Image quality poor Input dose of radiation increases exponentially Scatter radiation more As complexity increases. Procedure Related Issues to Minimize Exposure to Patient and Operator Utilize radiation only when imaging is necessary Minimize use of cine Minimize use of steep angles of X-ray beam Minimize use of magnification modes Minimize frame rate of fluoroscopy and cine Keep the image receptor close to the patient Utilize collimation to the fullest extent possible Monitor radiation dose in real time to assess patient risk/benefit during the procedure Tube Position and Scatter The scatter profile tilts as the x-ray tube is moved from the posterior to the anterior projection or when the tube is moved toward the cranial or caudal projections. Procedure Related Issues to Specifically Minimize Exposure to Operator Use and maintain appropriate protective garments Maximize distance of operator from X-ray source and patient Keep above-table and below-table shields in optimal position at all times Keep all body parts out of the field of view at all times Inverse Square Law 2 2 I / I = (d ) / (d ) 1 2 2 1 This relationship shows that doubling the distance from a radiation source will decrease the exposure rate to 1/4 the original. Staff Radiation Protection Shielding Lead>90%;Proper care of aprons Thyroid shielding; <40 yo The Next Armani? Staff Exposure Limits Whole Body 5 rem (50 mSv)/yr Eyes 15 rem (150 mSv)/ yr Pregnant Women 50 mrem (0. Risk Management of Skin Effects in Interventional Procedures Individualized management by an experienced radiation wound care team should be provided for wounds related to high dose radiation. M alalignment of the teeth such as crowding, abnormal the teeth that results in localized dissolution and destruction spacing, etc. It is the second m ost com m on cause of tooth loss and is found universally, irrespective of age, Saliva5–8 sex, caste, creed or geographic location. N orm ally, 700– be a disease of civilized society, related to lifestyle factors, 800 ml of saliva is secreted per day.
Observation of this reflex may require a second person due to the lateral placement of the globes elimite 30gm otc. The equine pupil responds slower than the cat or dog and as with all animals order elimite 30 gm on line, its presence does not confirm sight. Finnoff Transilluminator Excitement or opacity of the ocular media from blood, pus or cataract will not override the reflex from a bright focal light source. Inexpensive Lights Intermediate Examination Process Now a more through evaluation of the external eye can be done and systemic analgesic/sedatives could be given at this point if deemed necessary, which will not affect the subsequent portions of the examination. Use of an neck twitch or lip twitch is also often necessary during the moment of more uncomfortable examination procedures. Such as, at the time the periocular nerve block injections are made, eversion of the eyelids, especially the third eyelid and perhaps when the nasolacrimal system is flushed. Close Inspection For the majority of the examination minimal restraint is usually optimal and holding the horse by the halter seems to work well. Close evaluation of the eyelid margins, conjunctiva, cul de sacs and cornea for abnormalities can effectively be done with a bright light source and magnification. A head loupe such as an "Opti-Visor" is very helpful in addition to an adequate light source. The otoscope will provide a 3 x – 5x magnification and a powerful light source all in one. Opacities in the Ocular Media With the direct ophthalmoscope set at 0 diopters and viewing the eye from a distance of about one to two feet, an evaluation of the of the ocular media for opacities. Opacities in the Ocular Media The best situation is when the pupil is dilated artificially with tropicamide (1%) – do not use atropine for diagnostic purposes. This will allow the examiner to briefly evaluate the lens and vitreal space in this indirect manner for synechia, cataracts, vitreal floaters and retinal detachments. Opacities in the Ocular Media Later, when it is more appropriate to use a mydriatic, this indirect examination with the direct ophthalmoscope can be repeated when the pupil is large. Opacities that are anterior to the center of the lens will move in the same direction of the globe and ones posterior to the center of the lens will move in the opposite direction. Retinal detachments, if large will be seen easier with this method than looking directly. Ocular Opacity Focal Beam Examination Using a focal beam and or a slit beam directed into the eye at an angle evaluate the anterior chamber. Evaluation of the chamber contents and depth are essential as well as the character of the pupillary margin with regard to adhesions of the iris to the lens and pigment deposits on the anterior surface of the lens and the physical condition of the corpora nigra. Slit Light Examination Localization of an opacity Slit Light Examination Localization of an opacity Slit Light Examination Flare The aqueous is normally optically clear. When the blood aqueous barrier is broken down due to inflammation, the aqueous becomes more like plasma, or plasmoid. If a focal light is then shown in to the eye from an angle, the light will reflect off the protein and or cells as a haze or dust when there is flare or if inflammatory cells are present, respectively. Observation of the beam or slit of light passing through the anterior chamber with the aid of magnification (head loupe) increases the observers ability to see these changes. Retinal Examination Direct Ophthalmoscopy At this point the examiner can move close (1-2") and focus on the retina by adjusting the diopter wheel (usually 0 to -3). The magnification is about 15 times and the field of view is slightly larger than the optic disc. Direct Ophthalmoscopy Most inexperienced examiners usually get a good view of the tapetal retina and disc but not the nontapetal zone. Direct Ophthalmoscopy After the retina has been evaluated the examiner can move the diopter wheel to more positive numbers to evaluate the vitreous and lens. This instrument is a bit cumbersome for these structures because the depth of field at this magnification is so narrow. Indirect ophthalmoscopy Indirect ophthalmoscopy can also be done using a bright hand held light source and a hand lens (5 - 7 x). The hand lens could be as simple as a 7 - 5 x (28 -20 diopter) Bausch and Lomb plastic lens or a aspheric 20, 2. Indirect ophthalmoscopy Periocular Nerve Blocks Subsequent examination techniques that involve manipulations, especially in an animal that is already exhibiting signs of ocular pain usually require the additional assistance of one or several periocular nerve blocks. Periocular Nerve Block 1 Periocular Nerve Block 1 Periocular Nerve Block 1 Periocular Nerve Block Method 1 Inject 0. A 25 x 5/8" needle should enter at a point just below the arch and penetrate until the tip hits the bone, then slide needle foward until the tip is at the crest of the arch. Periocular Nerve Block 2 Palpate a cord of tissue at the lowest point of the cranial portion of the zygomatic arch and place 0. Periocular Nerve Block 3 Find the supraorbital foramen by placing your thumb on the superior orbital rim and your middle finger on the edge of the supraorbital fossa; then slide your hand medially and as your two fingers separate; drop your index finger down to touch the skull. Usually your index finger will fall into the foramen at this point, unless you are dealing with a draft horse. There is a branch of the auriculpalpebral nerve that passes over the surface of the foramen and this block will provide mostly akinesia of the upper lid with some analgesia to the central upper lid.
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