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Neuromuscular Junction Disease
Neuromuscular junction disease is a medical condition where the normal conduction through the neuromuscular junction fails to function correctly. Autoimmune In diseases such as myasthenia gravis, the end plate potential (EPP) fails to effectively activate the muscle fiber due to an autoimmune reaction against acetylcholine receptors, resulting in muscle weakness and fatigue. Myasthenia gravis is caused most commonly by auto-antibodies against the acetylcholine receptor. It has recently been realized that a second category of gravis is due to auto-antibodies against MuSK. A different condition, Lambert–Eaton myasthenic syndrome, is usually associated with ''presynaptic'' antibodies to the voltage-dependent calcium channel. It is possible for these conditions to coexist. Neuromuscular junction The neuromuscular junction is a specialized synapse between a neuron and the muscle it innervates. It allows efferent signals from the nervous system to contract muscle fibers causing them ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neurology
Neurology (from el, wikt:νεῦρον, νεῦρον (neûron), "string, nerve" and the suffix wikt:-logia, -logia, "study of") is the branch of specialty (medicine), medicine dealing with the diagnosis and treatment of all categories of conditions and disease involving the brain, the spinal cord and the peripheral nerves. Neurological practice relies heavily on the field of neuroscience, the scientific study of the nervous system. A neurologist is a physician specializing in neurology and trained to investigate, diagnose and treat neurological disorders. Neurologists treat a myriad of neurologic conditions, including stroke, seizures, movement disorders such as Parkinson's disease, autoimmune neurologic disorders such as multiple sclerosis, headache disorders like migraine and dementias such as Alzheimer's disease. Neurologists may also be involved in clinical research, clinical trials, and basic research, basic or translational research. While neurology is a nonsurgical sp ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Excitation–contraction Coupling
Muscle contraction is the activation of tension-generating sites within muscle cells. In physiology, muscle contraction does not necessarily mean muscle shortening because muscle tension can be produced without changes in muscle length, such as when holding something heavy in the same position. The termination of muscle contraction is followed by muscle relaxation, which is a return of the muscle fibers to their low tension-generating state. For the contractions to happen, the muscle cells must rely on the interaction of two types of filaments which are the thin and thick filaments. Thin filaments are two strands of actin coiled around each, and thick filaments consist of mostly elongated proteins called myosin. Together, these two filaments form myofibrils which are important organelles in the skeletal muscle system. Muscle contraction can also be described based on two variables: length and tension. A muscle contraction is described as isometric if the muscle tension changes b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electromyography
Electromyography (EMG) is a technique for evaluating and recording the electrical activity produced by skeletal muscles. EMG is performed using an instrument called an electromyograph to produce a record called an electromyogram. An electromyograph detects the electric potential generated by muscle cells when these cells are electrically or neurologically activated. The signals can be analyzed to detect abnormalities, activation level, or recruitment order, or to analyze the biomechanics of human or animal movement. Needle EMG is an electrodiagnostic medicine technique commonly used by neurologists. Surface EMG is a non-medical procedure used to assess muscle activation by several professionals, including physiotherapists, kinesiologists and biomedical engineers. In Computer Science, EMG is also used as middleware in gesture recognition towards allowing the input of physical action to a computer as a form of human-computer interaction. Clinical uses EMG testing has a variety of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Repetitive Nerve Stimulation
Repetitive nerve stimulation is a variant of the nerve conduction study where electrical stimulation is delivered to a motor nerve repeatedly several times per second. By observing the change in the muscle electrical response (CMAP) after several stimulations, a physician can assess for the presence of a neuromuscular junction disease, and differentiate between presynaptic and postsynaptic conditions. The test was first described by German neurologist Friedrich Jolly in 1895, and is also known as Jolly's test. Medical uses Repetitive nerve stimulation is used to diagnose neuromuscular junction (NMJ) disorders, the most common of which is myasthenia gravis. A decremental response (a smaller and smaller muscle response with each repetitive stimulus) is abnormal and indicates NMJ dysfunction. This can be further confirmed if the response normalizes after administration of edrophonium or neostigmine. Mechanism Stimulation of a motor neuron causes it to release acetylcholine, which is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylcholinesterase
Acetylcholinesterase (HGNC symbol ACHE; EC 3.1.1.7; systematic name acetylcholine acetylhydrolase), also known as AChE, AChase or acetylhydrolase, is the primary cholinesterase in the body. It is an enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. A ... that catalysis, catalyzes the breakdown of acetylcholine and some other choline esters that function as neurotransmitters: : acetylcholine + H2O = choline + acetate It is found at mainly neuromuscular junctions and in chemical synapses of the cholinergic type, where its activity serves to terminate neurotransmission, synaptic transmission. It belongs to the carboxylesterase family of enzymes. It is the primary target of inhibition by organophosphorus compounds such as nerve agents and pesticides. Enzyme structure and mechani ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hypermagnesemia
Hypermagnesemia is an electrolyte disorder in which there is a high level of magnesium in the blood. Symptoms include weakness, confusion, decreased breathing rate, and decreased reflexes. Complications may include low blood pressure and cardiac arrest. It is typically caused by kidney failure or is treatment-induced such as from antacids that contain magnesium. Less common causes include tumor lysis syndrome, seizures, and prolonged ischemia. Diagnosis is based on a blood level of magnesium greater than 1.1 mmol/L (2.6 mg/dL). It is severe if levels are greater than 2.9 mmol/L (7 mg/dL). Specific electrocardiogram (ECG) changes may be present. Treatment involves stopping the magnesium a person is getting. Treatment when levels are very high include calcium chloride, intravenous normal saline with furosemide, and hemodialysis. Hypermagnesemia is uncommon. Rates among hospitalized patients in renal failure may be as high as 10%. Signs and symptoms Symptoms includ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Autoimmune Disorders
An autoimmune disease is a condition arising from an abnormal immune response to a functioning body part. At least 80 types of autoimmune diseases have been identified, with some evidence suggesting that there may be more than 100 types. Nearly any body part can be involved. Common symptoms can be diverse and transient, ranging from mild to severe, and generally include low grade fever and feeling tired. The cause is unknown. Some autoimmune diseases such as lupus run in families, and certain cases may be triggered by infections or other environmental factors. Some common diseases that are generally considered autoimmune include celiac disease, diabetes mellitus type 1, graves' disease, inflammatory bowel disease, multiple sclerosis, alopecia areata, addison’s disease, pernicious anemia, psoriasis, rheumatoid arthritis, and systemic lupus erythematosus. The diagnosis can be difficult to determine. Treatment depends on the type and severity of the condition. Nonsteroida ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
HIV/AIDS
Human immunodeficiency virus infection and acquired immunodeficiency syndrome (HIV/AIDS) is a spectrum of conditions caused by infection with the human immunodeficiency virus (HIV), a retrovirus. Following initial infection an individual may not notice any symptoms, or may experience a brief period of influenza-like illness. Typically, this is followed by a prolonged incubation period with no symptoms. If the infection progresses, it interferes more with the immune system, increasing the risk of developing common infections such as tuberculosis, as well as other opportunistic infections, and tumors which are rare in people who have normal immune function. These late symptoms of infection are referred to as acquired immunodeficiency syndrome (AIDS). This stage is often also associated with unintended weight loss. HIV is spread primarily by unprotected sex (including anal and vaginal sex), contaminated blood transfusions, hypodermic needles, and from mother to ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Immune-mediated
An immune disorder is a dysfunction of the immune system. These disorders can be characterized in several different ways: * By the component(s) of the immune system affected * By whether the immune system is overactive or underactive * By whether the condition is congenital or acquired According to the International Union of Immunological Societies, more than 150 primary immunodeficiency diseases (PIDs) have been characterized. However, the number of acquired immunodeficiencies exceeds the number of PIDs. It has been suggested that most people have at least one primary immunodeficiency. Due to redundancies in the immune system, though, many of these are never detected. Autoimmune diseases An autoimmune disease is a condition arising from an abnormal immune response to a normal body part. There are at least 80 types of autoimmune diseases. Nearly any body part can be involved. Common symptoms include low-grade fever and feeling tired. Often symptoms come and go. List of some au ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Botulism
Botulism is a rare and potentially fatal illness caused by a toxin produced by the bacterium ''Clostridium botulinum''. The disease begins with weakness, blurred vision, feeling tired, and trouble speaking. This may then be followed by weakness of the arms, chest muscles, and legs. Vomiting, swelling of the abdomen, and diarrhea may also occur. The disease does not usually affect consciousness or cause a fever. Botulism can be spread in several ways. The bacterial spores which cause it are common in both soil and water. They produce the botulinum toxin when exposed to low oxygen levels and certain temperatures. Foodborne botulism happens when food containing the toxin is eaten. Infant botulism happens when the bacteria develops in the intestines and releases the toxin. This typically only occurs in children less than six months old, as protective mechanisms develop after that time. Wound botulism is found most often among those who inject street drugs. In this situation, spore ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Congenital Myasthenic Syndrome
Congenital myasthenic syndrome (CMS) is an inherited neuromuscular disorder caused by defects of several types at the neuromuscular junction. The effects of the disease are similar to Lambert-Eaton Syndrome and myasthenia gravis, the difference being that CMS is not an autoimmune disorder. There are only 600 known family cases of this disorder and it is estimated that its overall frequency in the human population is 1 in 200,000. Types The types of CMS are classified into three categories: presynaptic, postsynaptic, and synaptic. * ''Presynaptic'' symptoms include brief stops in breathing, weakness of the eye, mouth, and throat muscles. These symptoms often result in double vision and difficulty chewing and swallowing. * ''Postsynaptic'' symptoms in infants include severe muscle weakness, feeding and respiratory problems, and delays in the ability to sit, crawl, and walk. * ''Synaptic'' symptoms include early childhood feeding and respiratory problems, reduced mobility, curva ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
