...Introduction Myasthenia gravis is an autoimmune disease in which antibodies are produced that block or destroy the nicotine acetylcholine receptors at the postsynaptic membrane, causing muscle weakness and fatigue (Pendleton & Schultz-Krohn, 2006). Myasthenia gravis can occur at any age but onset usually occurs at an earlier age in women than in men. In the United States, there are about 14.2 cases of myasthenia gravis per one million people (Pendleton & Schultz-Krohn, 2006). Myasthenia gravis will be discussed in this paper according to the following: etiology, signs and symptoms, pathology and the progression of myasthenia gravis, diagnosis, prognosis, medical interventions, complications and resulting dysfunction of myasthenia gravis. Etiology Romi, Gilhus, and Aarli (2005) point to a genetic predisposition for myasthenia gravis with 30% of patients having mothers with myasthenia gravis or another autoimmune disease (p. 136). Other precipitating factors may include surgery, certain drugs, infection, and disorders of the thymus (Beers & Porter, 2006, p. 1899). Approximately 12% of babies born to mothers with myasthenia gravis display a passing muscle weakness termed “neonatal myasthenia” (Keesy, 2004, p. 485) not considered autoimmune, due to maternal antibodies crossing the placenta. Myasthenia gravis occurs at any age with the peak onset age in males between 50 and 70 years and in females between the teens and the thirties. Both...
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...Myasthenia gravis is an autoimmune disease that affects neuromuscular transmission. Antibodies attack acetylcholine receptors in the muscles resulting in weakness and fatigue. Symptoms typically first present as ocular myasthenia, intermittent ocular muscle fatigue causes diplopia and ptosis of the upper eyelid. Other symptoms may include: difficulty breathing due to fatigue of the chest wall muscles, trouble with chewing and swallowing, difficulty talking, drooping of the head and difficulty performing daily activities (A.D.A.M. Medical Encyclopedia, 2011). While it is the most common neuromuscular transmission disorder, myasthenia gravis only affects around one out of every ten-thousand persons with a higher incidence in young adult females (Cohen, Camilo, Lawrence, & Thomas, 2008). Normal Neuromuscular Transmission Muscles are controlled by nerve impulses originating in the brain. These impulses are sent via nerve fibers to the muscles being controlled. As the impulse reaches the end of the nerve fiber, vesicles release the neurotransmitter acetylcholine by exocytosis. Acetylcholine crosses the neuromuscular junction to receptor sites on the end plate membrane of the muscle. Muscles contract as a result of the acetylcholine binding to these receptors (Myasthenia Gravis Foundation of America, Inc.). To terminate the neuromuscular transmission, acetycholinesterase and diffusion deactivates the acetylcholine. Pathophysiology and Treatment of Myasthenia Gravis ...
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...The hypothesis is accepted, and the diagnosis is made: this man has myasthenia gravis. Myasthenia gravis is an autoimmune disease that typically affects both men and women who are in their 30’s, and it causes widespread muscle weakness by destroying the acetylcholine receptors. Myasthenia gravis usually begins with progressive muscle weakness that starts with the eyes and progresses to the mouth and other areas of the skeletal muscle. The acetylcholine synapse is a chemical synapse, it is composed of a presynaptic side which releases the neurotransmitter acetylcholine and postsynaptic side which houses gated ion channel receptors that bind to the acetylcholine neurotransmitter. Myasthenia gravis destroys those post-synaptic receptors. Therefore, acetylcholine is unable to bind to the receptors. When the action potential arrives at the axon terminal of the somatic motor...
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...Myasthenia Gravis and Physical Therapy Student’s Name Professor’s Name Class Institution of Affiliation Date of Submission Myasthenia Gravis and Physical Therapy Myasthenia Gravis According to medical research studies, Myasthenia Gravis is an autoimmune disease that develops when an individual’s immune system makes certain antibodies that affect its tissues. The antibodies produced by the body destroy or block muscle receptors that are fundamental in communication between the nerve-to-muscle and muscle contraction. The receptors are often referred to as acetylcholine (National Institute of Neurological Disorders and Stroke, 2010). The condition results in weakness of muscles and the effects tend to increase a lot when one is involved in physical activity that only reduces after resting. The most important fact to note is that the degree by which muscle weakness occurs due to myasthenia differs greatly among the affected individuals. The difference ranges from a localized form that is only limited to ocular myasthenia to a more severe form in which other muscles, such as those that control breathing, are affected (Drachman, 1994). In the traditional context, the condition has often been regarded to affect both genders and all ethnic groups. The most common cases are often found in younger women under the age of 40 and older men over the age of 60, although the condition can occur at any given age within the population. Epidemiological studies done in Greece found a Female...
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...Myasthenia Gravis Diagnosis Myasthenia gravis is a chronic disease characterized by progressive weakness and fatigue of the voluntary muscles. It is caused by an abnormal breakdown in communication between your muscles and nerves. Although it can affect people of any age, it is commonly seen in females below the age of 40 and in males above the age of 60. While there is no cure, treatment for myasthenia gravis helps relieve its signs and symptoms. A myasthenia gravis diagnosis can be made after your doctor reviews your medical history, conducts a physical examination and performs some laboratory tests. Diagnosis of Myasthenia Gravis Myasthenia gravis is arare autoimmune disease characterized by skeletal muscle weakness. This chronic and progressive disorder causes your voluntary muscles to become weaker without thinning out (atrophy). To make a myasthenia gravis diagnosis,...
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...Treatment The treatment of Myasthenia Gravis is dependent upon whether it is seen as an autoimmune disease or a congenital neuromuscular disease within the patient. As an autoimmune disease, MG is treated through the usage of immunosuppressive drugs, medication with the intended goal of reducing the efficacy of the immune system. Some of these drugs include prednisone, azathioprine, cyclosporin, and mycophenolate, in order from most commonly used to least prevalent. Other less commonly used forms of treatment for autoimmune MG includes plasmapheresis, intravenous immunoglobulin therapy, and thymectomy. In general, MG results in antibodies focused against the nicotinic acetylcholine receptor, the cholinergic neuron receptor protein which signals...
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...Analysis of Indirect-acting Cholinergic Stimulants: Pyridostigmine and Neostigmine Vanessa Rhule Drugs can be are related by their chemical structure, the way they work or if they are used for the same purpose (Pubmed Health, 2012). A cholinergic stimulant is a class of drugs used to increase activity at acetylcholine synapses and can be further subdivided into two categories; direct and indirect acting cholinergic stimulants. This categorization is based on their mechanisms of action and specificity for clinical use (Ciccone, 2007). Direct-acting cholinergic stimulants increase activity at the acetylcholine synapses by binding directly with the cholinergic receptor on the other hand; indirect-acting cholinergic stimulants put forth the same effect by inhibiting the acetylcholinesterase enzyme situated on the cholinergic synapse. For the purpose of this paper, an analysis of indirect acting cholinergic stimulants will be completed, with focus on Pyridosigmine and Prostigmin and their implications to physical therapy practice. Indirect-Acting Cholinergic Stimulants Indirect-acting cholinergic stimulants are also known as Cholinesterase inhibitors or Anticholinesterase agents. Cholinesterase inhibitors increase activity at cholinergic synapses by preventing the acetylcholinesterase enzyme from breaking down acetylcholine (ACh) after its release from the presynaptic terminal. Cholinesterase inhibitors inhibit acetylcholinesterase thus allowing more acetylcholine to remain...
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... Myasthenia gravis is a chronic autoimmune neuromuscular disease characterized by varying degrees of weakness of the skeletal (voluntary) muscles of the body. The name myasthenia gravis, which is Latin and Greek in origin, literally means "grave muscle weakness." With current therapies, however, most cases of myasthenia gravis are not as "grave" as the name implies. In fact, for the majority of individuals with myasthenia gravis, life expectancy is not lessened by the disorder. The hallmark of myasthenia gravis is muscle weakness that increases during periods of activity and improves after periods of rest. Certain muscles such as those that control eye and eyelid movement, facial expression, chewing, talking, and swallowing are often, but not always, involved in the disorder. The muscles that control breathing and neck and limb movements may also be affected. Myasthenia gravis is caused by a defect in the transmission of nerve impulses to muscles. It occurs when normal communication between the nerve and muscle is interrupted at the neuromuscular junction - the place where nerve cells connect with the muscles they control. Normally when impulses travel down the nerve, the nerve endings release a neurotransmitter substance called acetylcholine. Acetylcholine travels through the neuromuscular junction and binds to acetylcholine receptors which are activated and generate a muscle contraction. In myasthenia gravis, antibodies block, alter...
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...Discussion The aim of the present study was to determine the substrate specificity of AChE and BChE by testing these cholinesterases in the presence of a number of cholinergic compounds. Also to investigate the sensitivity of AChE and BChE to various cholinesterase inhibitors. Referring to the results of this experiment, it demonstrated that AChE had limited substrate specificity, whereas BuChE had extensive substrate specificity. BuChE hydrolysed BuCh faster when compared to Ach. It also hydrolysed other esters such as suxamethonium and neostigmine. It is evident that hypothesis for this research are accepted, and the substrate specificity of both compounds can be determined in cholinergic compound and the sensitivity in various cholinesterase inhibitors. George and Balasubramanian’s (1981) the aryl acylamidases and their relationship to cholinesterases in human serum, erythrocytes and liver study concluded that liver and aryl acylamidase when compared with erythrocyte aryl acylamidase was associated with acetylcholinesterase. Erythrocyte and serum aryl acylamidase illustrated some similarities in their sensitivities to amine compounds like serotonin and choline derivatives, the liver enzyme had no effect to any of these compounds. The liver aryl acylamidase differed from cholinesterase inhibitor. This is evident in other researchers work e.g. Miao et al., 2010. Human serum when compared to horse serum cholinesterase showed the differences in specificity. It showed that...
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...The muscular system derives of smooth muscles, skeletal muscles, and cardiac muscle. Smooth muscles are those that surround hollow organs while skeletal muscles attach the skeleton to form the flesh of the body and cardiac muscle is found only in the heart. Just like any other body system, there can be affective problems. Neuromuscular junction disorders impair the transmission of nerve signals to muscles. Myasthenia Gravis is the most common neuromuscular junction disorder. The discovery of Myasthenia Gravis was in early 1970’s and its condition causes a breakdown in communication between nerves and muscles. This characterization considers to cause highly changes of weakness of the skeletal muscles and it can be harder for operation. MG...
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...Ανασκόπηση Όγκοι του Θύμου Αδένα – Τι γνωρίζουμε; ΧΑρΑλΑμπος Ζήςής Χειρ. Θώρακος, Επιμελητής Νοσοκομείου «Ευαγγελισμός» Ο θύμος αδένας θεωρήθηκε για μεγάλο χρονικό διάστημα όργανο χωρίς ιδιαίτερη σημασία στις λειτουργίες του οργανισμού. Η εξαίρεσή του μάλιστα αποφασιζόταν εύκολα, ειδικά στην καρδιοχειρουργική προκειμένου να εξασφαλιστεί καλύτερη προσπέλαση στην καρδιά. Η αντίληψη αυτή άρχισε να αλλάζει από τα μέσα της δεκαετίας του 1960, με την αναγνώριση της κεντρικής θέσης που κατέχει στη διαδικασία της ανοσίας 1 και στην ανάπτυξη των Τ-λεμφοκυττάρων . Στο κείμενο που ακολουθεί παρουσιάζονται συνοπτικά τα τελευταία δεδομένα για την αντιμετώπιση των όγκων του θύμου αδένα. Ανατομία Η εμφάνιση του αδένα ποικίλλει σημαντικά και διαφέρει ανάλογα με την ηλικία. Είναι μεγαλύτερος κατά την πρώιμη περίοδο της ζωής μέχρι την ηλικία των 15 ετών, μολονότι παραμένει ενεργό όργανο ακόμη και σε γεροντική ηλικία. Είναι μαλθακής συστάσεως, δίλοβο όργανο, με συνδετικό ιστό στη μέση γραμμή που συγχωνεύεται με την κάψα του κάθε λοβού. Στα παιδιά είναι περισσότερο πυραμοειδές στο σχήμα και στερεότερο στη σύσταση απ’ό,τι στη μετέπειτα ζωή, όταν πια μειώνεται ο λεμφικός ιστός. Στη γέννηση είναι περίπου 10-15gr, γρήγορα φτάνει τα 20gr και μένει σ’αυτό το επίπεδο ακολούθως, παρά τη μείωση που επέρχεται βαθμιαία στην ποσότητα του λεμφικού ιστού. Η θέση που τυπικά καταλαμβάνει ο θύμος είναι το πρόσθιο-άνω μεσοθωράκιο, ανάμεσα στο στέρνο και το περικάρδιο. Προσθίως βρίσκεται το στέρνο, τα παρακείμενα...
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...As. J. Food Ag-Ind. 2012, 5(05), 364-373 Asian Journal of Food and Agro-Industry ISSN 1906-3040 Available online at www.ajofai.info Research Article Kinetics of the reduction of pesticide residues in vegetables by ultrasonic cleaning Ratikorn Buakham1, Sirichai Songsermpong1* and Chutima Eamchotchawalit2 1 Food Engineering Program, Department of Food Science and Technology, Faculty of Agro-Industry, Kasetsart University, Jatujak, Bangkok 10900, Thailand. Thailand Institute of Scientific and Technological Research. Klong Luang, Pathumthani 12120, Thailand. 2 Email: sirichai.so@ku.ac.th Abstract The problem of pathogen and pesticide residues in vegetables is a big concern to both consumers and exporters. This study introduced a new method of cleaning vegetables with high frequency sound waves (ultrasonic) as a way to solve the problem. This research aimed at studying the kinetics of reduction of pesticide residues in four kinds of vegetables: coriander, kale, yard long bean and red chili by using the ultrasonic cleaner (60 kHz 140 W) with tap water compared with soaking in tap water. The cleaning was done at 20, 25 and 30oC for 0, 3, 7 and 10 minutes. The determination of the toxicity levels was done by means of cholinesterase inhibition technique. The decimal reduction time, the reaction rate constant and the activation energy were determined. It was found that ultrasonic cleaning at 25oC and soaking in tap water at 30oC was the best combination to reduce...
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...talking, that he has a slurring of his words. The patients also stated he has an appointment with his primary care provider later on this week. What could be causing the symptoms thispatient is experiencing? Myasthenia gravis (MG) is an acquired, autoimmune-neuromuscular disease that has many signs, symptoms and some treatment options, dental professionals will need to alter their treatment to accommodate these patients. Pathophysiology Myasthenia gravis is pronounced ( my- as-thenia -grav- is). MG is...
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...The lymphocytes are very small. When doctors look at the sample of the affected lymph node under the microscope, they see lots of lymphocytes with very few Red Sternberg Cells”. Myasthenia Gravis is an autoimmune condition that affects the nerves and muscles present in the body. These types of conditions occur due to the body’s immune system incorrectly attacking healthy tissues. In Myasthenia Gravis, the immune system produces antibodies (also known as proteins), that block/damage muscle receptor cells. This blockage/damage prevents messages being passed from the nerve endings to the muscles thus preventing the muscles from contracting and results in them becoming weak. In a healthy individual the thymus gland is of normal size and carries out its function correctly without any problems. In an individual who has Myasthenia Gravis, the thymus gland will develop a tumour. This is called thymoma. This is usually non-cancerous (benign), however in a very small number of cases it can be cancerous...
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...ANT250 I Anatomy and Physiology I The Muscular System Module Three Case Assignment 20 May 2013 Professor: Dr. Koronika Q1. Describe normal anatomy/physiology of muscle contraction. Anatomy of Skeletal Muscle: A single skeletal muscle, such as the triceps muscle, is attached at its • Origin to a large area of bone; in this case, the humerus. • At its other end, the insertion, it tapers into a glistening white tendon which, in this case, it’s attached to the ulna, one of the bones of the lower arm. As the triceps contracts, the insertion are pulled toward the origin and the arm is straightened or extended at the elbow. Thus the triceps is an extensor. Because skeletal muscle exerts force only when it contracts, a second muscle a flexor is needed to flex or bend the joint. The biceps muscle is the flexor of the lower arm. Together, the biceps and triceps make up an antagonistic pair of muscles. Similar pairs, working antagonistically across other joints, provide for almost all the movement of the skeleton. The Muscle Fiber Skeletal muscle is made up of thousands of cylindrical muscle fibers often running all the way from origin to insertion. The fibers are bound together by connective tissue through which run blood vessels and nerves. Each muscle fibers contains: • An array of myofibrils that are stacked lengthwise and run the entire length of the fiber; • Mitochondria; • An extensive smooth endoplasmic reticulum (SER) ...
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