By F. Lares. University of Alabama, Huntsville.

On physical exam- ination cheap orlistat 60 mg fast delivery, it is often very difficult to localize the problem because when these children are relaxed they have full hip range of motion with no pain generic orlistat 120 mg mastercard. There usually seems to be no reason why these children should not be able to make progress in rehabilitation or gain straight upright stance. Radiographs may show only some slight medial protrusion of the blade plate and, occasion- ally, if the rotation of the femur is not correct, this may not even show as the plate is directed slightly anteriorly. In this clinical scenario, the plate should Figure 10. A common complaint after proximal femoral osteotomy is that the child is not comfortable side lying. An easy solu- tion is to suggest that the caretakers roll up a soft blanket and place it just proximal to the hip joint. This usually makes the side lying much more comfortable. He made slow progress in his re- to probably penetrate the femoral neck anteromedially covery; however, he seemed not to be able to get back to under the iliopsoas tendon (Figure C10. The plate independent standing and walking even by 1 year after was removed and he was walking upright and indepen- surgery. Although the radiograph did not show the plate dent 3 months after the surgery. Degenerative Arthritis Acute degenerative arthritis may occur and cause severe hip pain in the re- habilitation phase between 3 and 6 months following hip reconstruction. Typically, these children do as expected, gaining range of motion and im- proved comfort until approximately 6 to 10 weeks postoperatively, when the hip pain slowly starts getting worse. By approximately 4 months after sur- gery, the pain may be so severe that any movement of the hip joint causes pain. In some of these children, a small range of motion is comfortable, but as soon as the hips are moved outside this window, they are very painful. Ra- diographs will typically demonstrate some narrowing of the hip joint space (Case 10. This narrowing often occurs in children who have a small ridge identified at the level of the triradiate cartilage in the acetabulum. During reconstruction, good coverage and reduction of the femur is ob- tained, but the femoral head sits somewhat laterally against this medial ridge. As the range of motion is started, this medial ridge is worn down, causing symptoms of degenerative arthritis and synovitis in the hip joint. When these symptoms are identified at the initial stage, antiinflammatory medication should be started following an antiinflammatory dose schedule usually using ibuprofen or naproxen. The hip joint should be injected with a deposteroid or 80 mg triamcinolone acetate, with a small dose of approximately 1 ml 10. This local anesthetic injection will quickly demon- strate that acute degenerative arthritis is the source of the pain, as the pain should be gone for 6 to 8 hours. A significant decrease in the pain should be expected in 48 to 72 hours after steroid injection. The hip joint injection of the steroids and bupivacaine hydrochloride can be performed in the outpatient clinic if physicians are confident that they can palpate the anatomy of the hip joint and are able to enter the hip joint. How- ever, in older children or in children with less-clear landmarks, it is better to perform the injection in the radiography suite under fluoroscopic control. Steroids can be injected every 4 weeks for up to three injections if the pain has not made substantial improvement. At the same time, if the children are also having trouble sleeping and are eating poorly, an antidepressant, typi- cally amitriptyline hydrochloride (Elavil) twice a day, should be started. The antidepressant will improve pain control, sleep, and general attitude. The outcome of treatment in this scenario has a very high success rate, with complete resolution of the hip pain in 3 to 6 months. Substantial re- modeling of the hip joint with recreation of hip joint space often occurs as new cartilage seems to heal in the hip joint. However, this remodeling really only works in children who have open growth plates, and we would be very hesitant to expect this kind of outcome in adults. We have had no experience using this regimen except in children with open growth plates. At 1 year af- ter reconstruction, in spite of these problems, there is usually good recreation or maintenance of hip joint space on radiographs. Sudden Pain in Therapy Following hip surgery, children who are doing very well with improved range of motion and a decrease in postoperative pain may suddenly develop in- creased pain in physical therapy. When this sudden increased pain occurs, it is very important to do a careful physical examination to ensure that an acute fracture has not occurred. The most common site of an acute fracture fol- lowing hip reconstruction is in the distal metaphysis of the femur or the prox- imal metaphysis of the tibia (Figure 10. These fractures are frequently missed by emergency room doctors and primary care physicians because families and therapists believe the pain is focused on the hip, where it has been throughout this rehabilitation phase. These fractures are especially com- mon in children who have been in spica casts. The fractures themselves are not hard to diagnose if a careful clinical examination is performed, as there is usually obvious swelling and tenderness present in the area surrounding Figure 10.

Animal studies Researchers have used animal models to examine the effect of cold on muscle physiology buy 60mg orlistat visa. There are generic orlistat 60mg with visa, of course, limitations to this research and temperature effect cannot always be generalised to humans. A number of studies confirm the effect of ice in reducing muscle temperature and, in a study of ice application for 20 minutes in sheep,21 intramuscular temperature reduction did not return to pretreatment levels after two hours. When ice was applied a second time, intramuscular temperature continued to fall. Higher temperatures were recorded in the traumatised limb. In a study of cold applied to the skin of the mouse, increased blood vessel permeability with fluid extravasation and oedema occurred with temperatures below 15ºC. In a study of the effect of ice on injured rat muscle, however, cryotherapy did not reduce microvascular diameters or decrease microvascular perfusion. Human studies Animal studies can help us understand the physiological effect of temperature reduction but the key to clinical care is to understand the therapeutic effect in clinical practice. A number of researchers have examined the effect of tissue temperature reduction, but it is difficult to compare the results of the different studies because of variation in research methods and measurements. The temperature reduction at tissue level is illustrated in one study where ice was applied continuously for 85 minutes27 and the temperature dropped by 5ºC, 9ºC and 7ºC at depths of 7 cm, 6 cm and 4 cm. Compression may also enhance temperature reduction28 with the changes at 1 cm below the fat layer and at 2 cm below the fat layer being greater with compression at 12⋅8ºC and 10⋅1ºC. Subcutaneous fat, being an insulating material, inhibits the cooling effect and while significant cooling occurs with 10 minutes of ice application to a depth of 2 cm in those with less than 1 cm of fat,29 athletes with more than 2 cm of fat, required 20–30 minutes. There is an inverse relationship between adipose tissue and temperature decrease so that subcutaneous fat may mean that short duration ice application may be ineffective in cooling deeper tissue levels. The above paragraphs highlight only some of the studies on ice application. The consensus from studies of ice application, for periods varying from five minutes to 85 minutes, is that the temperature is reduced in the first 10 minutes with little further reduction from 10 to 20 minutes. The temperature drop is determined by the area of contact between the ice and the skin, the temperature difference and tissue conductivity but most published studies do not measure the area of ice application, subcutaneous fat, nor use comparable methods of calculating depth, or measuring temperature. Where temperature is 48 The role of ice in soft tissue injury management measured, in human and animal studies, there is wide variation in the temperature recorded at different depths in different studies with wide standard deviations. It is almost impossible to consider the dynamic effect of tissue movement and blood flow on temperature and experimental measurements of tissue temperature cannot be directly compared to the effect on the injured athlete. Summary Subcutaneous fat is an insulator so may impair cold conduction A barrier should be used to prevent ice burns A wet towel is a most effective barrier and conductor Ice therapy may cause temporary neurological impairment Ice may temporarily impair muscle strength Application of different modalities Ice, or cold, is used in different ways. The standard ice application of melting iced water ensures a constant temperature of 0ºC. Ice taken straight from a freezer may be considerably below freezing point and reusable chemical gel packs may be as cold as −5 to −15ºC. Iced water may also be used in different ways, such as frozen in paper cups or in moulded packs, and convenience packs (for example frozen peas) have also been recommended. A temperature of 0ºC is certain with melting iced water, which is important as there is a risk of tissue damage and frostbite with excess cold. The traditional method of cryotherapy is through melting iced water, but there are a number of proprietary preparations available including chemical packs, reusable gels, sprays and applications. There is little research on comparison of the various methods although one animal study gives us particular insight. Ice can cause burns if applied directly to the skin34 so a barrier is usually recommended. This can, of course, act as an insulator and prevent cold conduction but this depends on the nature of the barrier. The effect of different barriers was clear after 30 minutes of ice application. Repeated 10 minute applications through a wet towel are most effective. Ice taken straight from a freezer may be below freezing point. Reusable chemical gel packs, may be as cold as −5 to −15°C. There is little research on comparison of the various methods. Effect on blood flow Cold is a vasoconstrictor, but there is some discussion about the possible paradoxical effect of cold application. This is described as the “hunting reflex”, and it is a physiological protective reflex to protect tissue from ice damage. This has been studied by Knight and Londeree37 who compared blood flow to the ankle under six experimental conditions using a cold pack and concluded that there was no cold induced vasodilation. These findings have been confirmed by Baker and Bell. Possible adverse affects Cooling is used to reduce swelling and muscle damage after injury but there are potential adverse effects associated with ice application which may be important if an athlete wishes to compete or train immediately after injury. Muscle cooling may inhibit muscle strength40 and Meeusen and Lievens41 suggest that motor performance is impaired at a critical temperature of 18ºC.

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Although the mechanisms are not well understood cheap orlistat 60 mg, this decrease in insulin secretion leads to increased hepatic glucose output (leading to fasting hyperglycemia) and reduced suppression of hepatic glucose output after meals generic orlistat 60mg, leading to postprandial hyperglycemia as well. If the patient has an underlying genetic predisposition to dia- betes mellitus, the superimposition of the mechanisms outlined above will lead to an earlier and more significant breakdown in glucose tolerance in these specific patients. BIOCHEMICAL COMMENTS Extensive and progressive fibrosis of the hepatic parenchyma leads to cir- rhosis of the liver, a process that has many causes. The development of fibrosis requires the activities of hepatic stellate cells, cytokines, proteases, and protease inhibitors. This occurs because of both an increased synthesis of a different type of collagen than is normally produced and a reduction in the turnover rate of existing extracel- lular matrix components. The supportive tissues of the normal liver contain an extracellular matrix that, among other proteins, includes type IV collagen (which does not form fibers), gly- coproteins, and proteoglycans. After a sustained insult to the liver, a threefold to eightfold increase occurs in extracellular matrix components, some of which con- tain fibril-producing collagen (types I and III), glycoproteins, and proteoglycans. The accumulation of these fibril-producing compounds leads to a loss of endothe- lial cell fenestrations and, therefore, a loss of the normal sieve-like function of the basement membranes. These changes interfere with normal transmembrane meta- bolic exchanges between the blood and hepatocytes. The hepatic stellate cell is the source of the increased and abnormal collagen production. These cells are activated by growth factors whose secretion is induced by injury to the hepatocytes or endothelial cells. Growth factors involved in cellu- lar activation include TGF- 1 (which is derived from the endothelial cells, Kupffer cells, and platelets) and platelet-derived growth factor (PDGF) and epidermal growth factor (EGF) from platelets. The release of PDGF stimulates stellate cell proliferation and, in the process, increases their synthesis and release of extracellu- lar matrix materials and remodeling enzymes. These enzymes include matrix metalloproteinases (MMPs) and tissue inhibitors of MMPs, as well as converting (activating) enzymes. This cascade leads to the degradation of the normal extracel- lular matrix and replacement with a much denser and more rigid type of matrix material. These changes are, in part, the result of an increase in the activity of tis- sue inhibitors of MMP’s for the new collagen relative to the original collagen in the extracellular matrix. One consequence of the increasing stiffness of the hepatic vascular channels through which hepatic blood must flow is a greater resistance to the free flow of blood through the liver as a whole. Resistance to intrahepatic blood flow is also increased by a loss of vascular endothelial cell fenestrations, loss of free space between the endothelial cells and the hepatocytes (space of Disse), and even loss of vascular channels per se. This increased vascular resistance leads to an elevation in intrasinusoidal fluid pressure. When this intrahepatic (portal) hypertension reaches a critical threshold, the shunting of portal blood away from the liver (portosystemic shunting) further contributes to hepatic dysfunction. If the portal hypertension can- not be reduced, portal blood will continue to bypass the liver and return to the heart through the normally low-pressure esophageal veins. When this increasing intrae- sophageal venous pressure becomes severe enough, the walls of these veins thin dramatically and expand to form varices, which may suddenly burst, causing life- threatening esophageal variceal hemorrhage. This is a potentially fatal complication of cirrhosis of the liver. Liver metabolism, in Metabolic Regulation in Mammals. Hepatic cirrhosis, in Diseases of the Liver and Biliary System, Chapter 21. Hepatobiliary disposition and targeting of drugs and genes, in Oxford Textbook of Clinical Hepatology, vol 1, 2nd Ed. CHAPTER 46 / LIVER METABOLISM 861 REVIEW QUESTIONS—CHAPTER 46 1. Drinking grapefruit juice while taking statins can lead to potentially devastating side effects. This is due to a component of grapefruit juice doing which of the following? Which one of the following characteristics of cytochrome P450 enzymes is correct? Fairly predictable changes occur in the various metabolic pathways of lipid metabolism in patients with moderately advanced hepatocellular disease. Which one of the following changes would you expect to see under these conditions? After a 2-week alcoholic binge, Jean Ann Tonich ingested some Tylenol to help her with a severe headache. She took three times the suggested dose because of the severity of the pain. However, within 24 hours Jean Ann became very lethargic, vom- ited frequently, and developed severe abdominal pain. The symptoms Jean Ann is experiencing are attributable to a reaction to the Tylenol due to which of the following? An individual displays impaired glucose tolerance; blood glucose levels remain elevated after a meal for a longer time than is normal, although they do eventually go down to fasting levels. The patient has a normal release of insulin from the pancreas in response to elevated blood glucose levels.

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Abstracts/Parkinson- ism Rel Disord 2001 discount orlistat 120 mg without prescription; (suppl 7):S60 orlistat 120mg without a prescription. Finberg JPM, Lamensdorf I, Commissiong JW, Youdim MBH. Pharmacol- ogy and neuroprotective properties of rasagiline. Rabey JM, Sagi I, Huberman M, Melamed E, for the Rasagiline Study Group. Rasagiline mesylate, a new MAO-B inhibitor for the treatment of Parkinson’s disease: a double-blind study as adjunctive therapy to levodopa. Pfeiffer University of Tennessee Health Science Center, Memphis, Tennessee, U. The introduction of levodopa therapy for Parkinson’s disease (PD), initially by Birkmayer and colleagues in 1961 and Barbeau and colleagues in 1962, and in its ultimately successful form by Cotzias and colleagues in 1967, still represents the defining landmark in the treatment of PD (1–3). This dramatic advance was preceded by methodical basic laboratory research in the late 1950s and early 1960s, which formed a groundwork documenting the presence of striatal dopamine deficiency in PD (4–8) and paved the road for the application of this knowledge in the clinical arena. These developments took place against a broader backdrop in which both the role of catecholamines and their metabolic pathways in body and brain were being unraveled (9). As part of this panorama, Axelrod, in 1957, first suggested that one of the metabolic pathways for catecholamines might be via O-methylation (9–11), and in the same year Shaw and colleagues proposed that catechol-O-methyltransferase (COMT) might be important in the inactivation of dihydroxyphenylalanine (DOPA) and dopamine (12). By 1964 the metabolic pathways for DOPA and dopamine had been delineated and the involved enzymes identified. Aromatic amino acid decarboxylase (AAAD) and COMT were identified as being responsible for converting Copyright 2003 by Marcel Dekker, Inc. DOPA to dopamine and 3-O-methyldopa (3-OMD), respectively, while monoamine oxidase (MAO) and COMT were documented as being responsible for converting dopamine to 3,4-dihydroxyphenylacetic acid (DOPAC) and 3-methoxytyramine (3-MT), respectively. As early as 1964 it was suggested that agents inhibiting COMT might potentiate the effects of DOPA (13). COMT is found throughout the body, with highest concentrations in the liver, kidneys, gastrointestinal tract, spleen, and lungs (14–17). It is also present in the brain, where it resides primarily in nonneuronal cells, such as glia. There is little COMT in neurons, and none has been identified in nigrostriatal dopaminergic neurons (18). It is principally a cytoplasmic enzyme, although a membrane-bound component has also been identified (11). A number of substrates are acted upon by COMT, including catecholamines such as epinephrine, norepinephrine, and dopamine and their hydroxylated metabolites, but all known substrates have a catechol configuration (11). COMT mediates the transfer of a methyl group from S- adenosylmethionine to a hydroxyl group on the catechol molecule. Its actions, especially in peripheral structures such as intestinal mucosa, seem to be primarily directed toward protecting the body by inactivating biologi- cally active or toxic catechol compounds (11,18,19). Both levodopa and dopamine are examples of such biologically active compounds. Recognition of the wretched bioavailability of orally administered levodopa in the treatment of PD, with perhaps only 1% of the levodopa actually reaching the brain because of extensive peripheral metabolism by both AAAD and COMT (18,20), fueled the search for drugs that might inhibit the two enzymes and improve levodopa therapeutic efficacy. This led relatively quickly to the introduction of two inhibitors of AAAD, carbidopa and benserazide, as adjunctive agents administered concomitantly with levodopa to PD patients (21,22). This approach of administering levodopa in conjunction with an AAAD inhibitor remains the standard today. However, use of these agents only expands the amount of levodopa reaching the brain to an estimated 10% of an administered dose, primarily because blocking AAAD simply shunts levodopa into the COMT metabolic pathway, with increased peripheral formation of 3-OMD (20). FIRST-GENERATION COMT INHIBITORS During the 1960s and 1970s a number of COMT inhibitors were identified and studied. Pyrogallol (1,2,3-trihydroxybenzene) was perhaps the first COMT inhibitor to be identified (23,24), but its short duration of action, toxicity (methemoglobinemia and renal impairment), and probable lack of COMT specificity precluded its clinical use (11). The list of additional ‘‘first- Copyright 2003 by Marcel Dekker, Inc. Catechol itself, adnamine and noradnamine, various flavonoids, tropolone and its derivatives, 8- hydroxyquinolines, S-adenosylhomocysteine, sulfhydryl binding agents, pyrones and pyridones, papaveroline, methylspinazarin, 2-hydroxylated estrogens, and 3-mercaptotyramine represent only a partial listing of such compounds (11). Even the two agents that are primarily recognized as inhibitors of AAAD, carbidopa and benserazide, have some modest COMT-inhibiting properties, although not enough to be clinically relevant (11). Several of these early COMT inhibitors did undergo pilot testing in humans. N-Butyl gallate (GPA 1714), a derivative of gallic acid, was found to be effective in alleviating signs and symptoms of PD when administered to 10 patients in a pilot study (25). The dose of levodopa was reduced by an average of 29%, and the drug was also noted to alleviate nausea and vomiting in affected patients. No significant adverse effects were noted in this initial study, but testing was eventually abandoned because of toxicity (26). Another compound, 3,4-dihydroxy-2-methylpropiophenone (U-0521), demonstrated significant COMT inhibition in animal studies in the laboratory, but when it was administered orally to a single human in progressively increasing doses it demonstrated no effect on erythrocyte COMT activity (26). SECOND-GENERATION COMT INHIBITORS Little literary attention was devoted to the subject of COMT inhibitors for the treatment of PD during the mid-1980s, but the dawning of the 1990s ushered in renewed interest in the potential clinical usefulness of these compounds. This attention was prompted by the development of a ‘‘second generation’’ of COMT inhibitors, substances that were more potent, more selective, and less toxic than their predecessors. Several nitrocatechol compounds, eventually bearing the names nitecapone, entacapone, and tolcapone, became the favored subjects of laboratory, and eventually clinical, focus. Nitecapone Nitecapone (OR 462) was demonstrated to be well tolerated and modestly effective when administered to mice, rats, and monkeys (27–29). Its actions were confined to the periphery since it did not cross the blood-brain barrier (30), and, in fact, its primary action appeared to be in the intestinal mucosa (31,32).

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