A disorder of neuromuscular transmission characterized by weakness of cranial and skeletal muscles. Autoantibodies directed against acetylcholine receptors damage the motor endplate portion of the NEUROMUSCULAR JUNCTION, impairing the transmission of impulses to skeletal muscles. Clinical manifestations may include diplopia, ptosis, and weakness of facial, bulbar, respiratory, and proximal limb muscles. The disease may remain limited to the ocular muscles. THYMOMA is commonly associated with this condition. (Adams et al., Principles of Neurology, 6th ed, p1459)
Any autoimmune animal disease model used in the study of MYASTHENIA GRAVIS. Injection with purified neuromuscular junction acetylcholine receptor (AChR) (see RECEPTORS, CHOLINERGIC) components results in a myasthenic syndrome that has acute and chronic phases. The motor endplate pathology, loss of acetylcholine receptors, presence of circulating anti-AChR antibodies, and electrophysiologic changes make this condition virtually identical to human myasthenia gravis. Passive transfer of AChR antibodies or lymphocytes from afflicted animals to normals induces passive transfer experimental autoimmune myasthenia gravis. (From Joynt, Clinical Neurology, 1997, Ch 54, p3)
Surgical removal of the thymus gland. (Dorland, 28th ed)
Cell surface proteins that bind acetylcholine with high affinity and trigger intracellular changes influencing the behavior of cells. Cholinergic receptors are divided into two major classes, muscarinic and nicotinic, based originally on their affinity for nicotine and muscarine. Each group is further subdivided based on pharmacology, location, mode of action, and/or molecular biology.
A neoplasm originating from thymic tissue, usually benign, and frequently encapsulated. Although it is occasionally invasive, metastases are extremely rare. It consists of any type of thymic epithelial cell as well as lymphocytes that are usually abundant. Malignant lymphomas that involve the thymus, e.g., lymphosarcoma, Hodgkin's disease (previously termed granulomatous thymoma), should not be regarded as thymoma. (From Stedman, 25th ed)
A cholinesterase inhibitor with a slightly longer duration of action than NEOSTIGMINE. It is used in the treatment of myasthenia gravis and to reverse the actions of muscle relaxants.
Tumors or cancer of the THYMUS GLAND.
Enlargement of the thymus. A condition described in the late 1940's and 1950's as pathological thymic hypertrophy was status thymolymphaticus and was treated with radiotherapy. Unnecessary removal of the thymus was also practiced. It later became apparent that the thymus undergoes normal physiological hypertrophy, reaching a maximum at puberty and involuting thereafter. The concept of status thymolymphaticus has been abandoned. Thymus hyperplasia is present in two thirds of all patients with myasthenia gravis. (From Segen, Dictionary of Modern Medicine, 1992; Cecil Textbook of Medicine, 19th ed, p1486)
A disorder of neuromuscular transmission that occurs in a minority of newborns born to women with myasthenia gravis. Clinical features are usually present at birth or develop in the first 3 days of life and consist of hypotonia and impaired respiratory, suck, and swallowing abilities. This condition is associated with the passive transfer of acetylcholine receptor antibodies through the placenta. In the majority of infants the myasthenic weakness resolves (i.e., transient neonatal myasthenia gravis) although this disorder may rarely continue beyond the neonatal period (i.e., persistent neonatal myasthenia gravis). (From Menkes, Textbook of Child Neurology, 5th ed, p823; Neurology 1997 Jan;48(1):50-4)
Antibodies that react with self-antigens (AUTOANTIGENS) of the organism that produced them.
Drooping of the upper lid due to deficient development or paralysis of the levator palpebrae muscle.
A rapid-onset, short-acting cholinesterase inhibitor used in cardiac arrhythmias and in the diagnosis of myasthenia gravis. It has also been used as an antidote to curare principles.
Drugs that inhibit cholinesterases. The neurotransmitter ACETYLCHOLINE is rapidly hydrolyzed, and thereby inactivated, by cholinesterases. When cholinesterases are inhibited, the action of endogenously released acetylcholine at cholinergic synapses is potentiated. Cholinesterase inhibitors are widely used clinically for their potentiation of cholinergic inputs to the gastrointestinal tract and urinary bladder, the eye, and skeletal muscles; they are also used for their effects on the heart and the central nervous system.
Procedure whereby plasma is separated and extracted from anticoagulated whole blood and the red cells retransfused to the donor. Plasmapheresis is also employed for therapeutic use.
A cholinesterase inhibitor used in the treatment of myasthenia gravis and to reverse the effects of muscle relaxants such as gallamine and tubocurarine. Neostigmine, unlike PHYSOSTIGMINE, does not cross the blood-brain barrier.
A genus of the Torpedinidae family consisting of several species. Members of this family have powerful electric organs and are commonly called electric rays.
The synapse between a neuron and a muscle.
A visual symptom in which a single object is perceived by the visual cortex as two objects rather than one. Disorders associated with this condition include REFRACTIVE ERRORS; STRABISMUS; OCULOMOTOR NERVE DISEASES; TROCHLEAR NERVE DISEASES; ABDUCENS NERVE DISEASES; and diseases of the BRAIN STEM and OCCIPITAL LOBE.
A single, unpaired primary lymphoid organ situated in the MEDIASTINUM, extending superiorly into the neck to the lower edge of the THYROID GLAND and inferiorly to the fourth costal cartilage. It is necessary for normal development of immunologic function early in life. By puberty, it begins to involute and much of the tissue is replaced by fat.
'Rats, Inbred Lew' is a strain of laboratory rat that is widely used in biomedical research, known for its consistent genetic background and susceptibility to certain diseases, which makes it an ideal model for studying the genetic basis of complex traits and disease processes.
Disorders that are characterized by the production of antibodies that react with host tissues or immune effector cells that are autoreactive to endogenous peptides.
One of the two major classes of cholinergic receptors. Nicotinic receptors were originally distinguished by their preference for NICOTINE over MUSCARINE. They are generally divided into muscle-type and neuronal-type (previously ganglionic) based on pharmacology, and subunit composition of the receptors.
Disorders that feature impairment of eye movements as a primary manifestation of disease. These conditions may be divided into infranuclear, nuclear, and supranuclear disorders. Diseases of the eye muscles or oculomotor cranial nerves (III, IV, and VI) are considered infranuclear. Nuclear disorders are caused by disease of the oculomotor, trochlear, or abducens nuclei in the BRAIN STEM. Supranuclear disorders are produced by dysfunction of higher order sensory and motor systems that control eye movements, including neural networks in the CEREBRAL CORTEX; BASAL GANGLIA; CEREBELLUM; and BRAIN STEM. Ocular torticollis refers to a head tilt that is caused by an ocular misalignment. Opsoclonus refers to rapid, conjugate oscillations of the eyes in multiple directions, which may occur as a parainfectious or paraneoplastic condition (e.g., OPSOCLONUS-MYOCLONUS SYNDROME). (Adams et al., Principles of Neurology, 6th ed, p240)
Ocular disorders attendant upon non-ocular disease or injury.
Paralysis of one or more of the ocular muscles due to disorders of the eye muscles, neuromuscular junction, supporting soft tissue, tendons, or innervation to the muscles.
Recording of the changes in electric potential of muscle by means of surface or needle electrodes.
An autoimmune disease characterized by weakness and fatigability of proximal muscles, particularly of the pelvic girdle, lower extremities, trunk, and shoulder girdle. There is relative sparing of extraocular and bulbar muscles. CARCINOMA, SMALL CELL of the lung is a frequently associated condition, although other malignancies and autoimmune diseases may be associated. Muscular weakness results from impaired impulse transmission at the NEUROMUSCULAR JUNCTION. Presynaptic calcium channel dysfunction leads to a reduced amount of acetylcholine being released in response to stimulation of the nerve. (From Adams et al., Principles of Neurology, 6th ed, pp 1471)
The specialized postsynaptic region of a muscle cell. The motor endplate is immediately across the synaptic cleft from the presynaptic axon terminal. Among its anatomical specializations are junctional folds which harbor a high density of cholinergic receptors.
Contractile tissue that produces movement in animals.
Neurotoxic proteins from the venom of the banded or Formosan krait (Bungarus multicinctus, an elapid snake). alpha-Bungarotoxin blocks nicotinic acetylcholine receptors and has been used to isolate and study them; beta- and gamma-bungarotoxins act presynaptically causing acetylcholine release and depletion. Both alpha and beta forms have been characterized, the alpha being similar to the large, long or Type II neurotoxins from other elapid venoms.
Immunoglobulin molecules having a specific amino acid sequence by virtue of which they interact only with the ANTIGEN (or a very similar shape) that induced their synthesis in cells of the lymphoid series (especially PLASMA CELLS).
An immunosuppressive agent used in combination with cyclophosphamide and hydroxychloroquine in the treatment of rheumatoid arthritis. According to the Fourth Annual Report on Carcinogens (NTP 85-002, 1985), this substance has been listed as a known carcinogen. (Merck Index, 11th ed)
A vague complaint of debility, fatigue, or exhaustion attributable to weakness of various muscles. The weakness can be characterized as subacute or chronic, often progressive, and is a manifestation of many muscle and neuromuscular diseases. (From Wyngaarden et al., Cecil Textbook of Medicine, 19th ed, p2251)
A genus of fish, in the family GYMNOTIFORMES, capable of producing an electric shock that immobilizes fish and other prey. The species Electrophorus electricus is also known as the electric eel, though it is not a true eel.
Conditions characterized by impaired transmission of impulses at the NEUROMUSCULAR JUNCTION. This may result from disorders that affect receptor function, pre- or postsynaptic membrane function, or ACETYLCHOLINESTERASE activity. The majority of diseases in this category are associated with autoimmune, toxic, or inherited conditions.
The muscles that move the eye. Included in this group are the medial rectus, lateral rectus, superior rectus, inferior rectus, inferior oblique, superior oblique, musculus orbitalis, and levator palpebrae superioris.
Removal of plasma and replacement with various fluids, e.g., fresh frozen plasma, plasma protein fractions (PPF), albumin preparations, dextran solutions, saline. Used in treatment of autoimmune diseases, immune complex diseases, diseases of excess plasma factors, and other conditions.
The major immunoglobulin isotype class in normal human serum. There are several isotype subclasses of IgG, for example, IgG1, IgG2A, and IgG2B.

Mutation causing congenital myasthenia reveals acetylcholine receptor beta/delta subunit interaction essential for assembly. (1/4)

We describe a severe postsynaptic congenital myasthenic syndrome with marked endplate acetylcholine receptor (AChR) deficiency caused by 2 heteroallelic mutations in the beta subunit gene. One mutation causes skipping of exon 8, truncating the beta subunit before its M1 transmembrane domain, and abolishing surface expression of pentameric AChR. The other mutation, a 3-codon deletion (beta426delEQE) in the long cytoplasmic loop between the M3 and M4 domains, curtails but does not abolish expression. By coexpressing beta426delEQE with combinations of wild-type subunits in 293 HEK cells, we demonstrate that beta426delEQE impairs AChR assembly by disrupting a specific interaction between beta and delta subunits. Studies with related deletion and missense mutants indicate that secondary structure in this region of the beta subunit is crucial for interaction with the delta subunit. The findings imply that the mutated residues are positioned at the interface between beta and delta subunits and demonstrate contribution of this local region of the long cytoplasmic loop to AChR assembly.  (+info)

Surgical correction of blepharoptosis in patients with myasthenia gravis. (2/4)

PURPOSE: To describe the results of surgical correction of blepharoptosis in a series of patients with myasthenia gravis. METHODS: We reviewed the medical records of all patients with myasthenia gravis who underwent surgical correction for blepharoptosis at the Mayo Clinic between 1985 and 1999. The primary outcome measure was change in interpalpebral eyelid fissure height. RESULTS: Eighteen blepharoptosis procedures were performed on 11 patients with myasthenia gravis. Eight of the 11 patients had ocular myasthenia gravis, and 3 had systemic myasthenia gravis. Of the 18 procedures performed, 11 were external levator advancements (ELA), 6 were frontalis slings, and 1 was a tarsomyectomy. Patients were followed up postoperatively for an average of 34 months (range, 9 to 126 months). The amount of ptosis was quantified preoperatively and postoperatively for 9 of the 11 eyelids that underwent ELA. For these eyelids, there was a statistically significant improvement in the mean interpalpebral eyelid fissure height, from 4.2 mm preoperatively to 8.1 mm postoperatively, with a mean difference of 3.9 mm (95% confidence interval, 2.3 to 5.5 mm; P = .0005). Postoperative complications included worsened diplopia in 1 patient who underwent ELA and exposure keratopathy in 1 patient who underwent a frontalis sling procedure. Two of the eyelids that underwent ELA developed recurrent ptosis, requiring additional surgery more than 2 years after the initial procedure. CONCLUSION: Surgical correction of blepharoptosis is an appropriate treatment option in patients with myasthenia gravis who fail medical therapy. Potential complications include worsened diplopia and exposure keratopathy.  (+info)

Seronegative neonatal myasthenia gravis in one of the twins. (3/4)

Neonatal myasthenia gravis has been described as a transient condition affecting only a small percent of neonates. We report a twin gestation in a seronegative mother with myasthenia gravis, in which only one twin was affected.  (+info)

The emerging diversity of neuromuscular junction disorders. (4/4)

Research advances over the last 30 years have shown that key transmembrane proteins at the neuromuscular junction are vulnerable to antibody-mediated autoimmune attack These targets are acetylcholine receptors (AChRs) and muscle specific kinase (MuSK) in myasthenia gravis, voltage-gated calcium channels (VGCCs) in the Lambert-Eaton myasthenic syndrome (LEMS), and voltage-gated potassium channels (VGKCs) in neuromyotonia. In parallel with these immunological advances, mutations identified in genes encoding pre-synaptic, synaptic and postsynaptic proteins that are crucial to neuromuscular transmission have revealed a similar diversity of congenital myasthenic syndromes (CMS). These discoveries have had a major impact on diagnosis and management.  (+info)

Myasthenia Gravis is a long-term autoimmune neuromuscular disorder that leads to muscle weakness. It occurs when communication between nerves and muscles is disrupted at the nerve endings, resulting in fewer impulses being transmitted to activate the muscles. This results in muscle weakness and rapid fatigue. The condition can affect any voluntary muscle, but it most commonly affects muscles of the eyes, face, throat, and limbs. Symptoms may include drooping eyelids (ptosis), double vision (diplopia), difficulty swallowing, slurred speech, and weakness in the arms and legs. The severity of symptoms can vary greatly from person to person, ranging from mild to life-threatening.

The disorder is caused by an abnormal immune system response that produces antibodies against the acetylcholine receptors in the postsynaptic membrane of the neuromuscular junction. These antibodies block or destroy the receptors, which leads to a decrease in the number of available receptors for nerve impulses to activate the muscle fibers.

Myasthenia Gravis can be treated with medications that improve communication between nerves and muscles, such as cholinesterase inhibitors, immunosuppressants, and plasmapheresis or intravenous immunoglobulin (IVIG) to remove the harmful antibodies from the blood. With proper treatment, many people with Myasthenia Gravis can lead normal or nearly normal lives.

Myasthenia gravis is a neuromuscular disorder characterized by muscle weakness and fatigability. In autoimmune myasthenia gravis, the immune system produces antibodies that attack the receptors at the junction between the nerve and muscle (the neuromuscular junction), impairing communication between the nerve and muscle and leading to muscle weakness.

The term "experimental" in this context typically refers to a research setting where the condition is being studied, rather than a specific medical definition for a type of myasthenia gravis. Experiments may involve investigating new treatment approaches, understanding the underlying mechanisms of the disease, or exploring potential causes and risk factors.

Therefore, 'Myasthenia Gravis, Autoimmune, Experimental' generally means that researchers are studying autoimmune myasthenia gravis in an experimental setting to advance our knowledge and develop better treatment strategies for this condition.

Thymectomy is a surgical procedure that involves the removal of the thymus gland. The thymus gland is a part of the immune system located in the upper chest, behind the sternum (breastbone), and above the heart. It is responsible for producing white blood cells called T-lymphocytes, which help fight infections.

Thymectomy is often performed as a treatment option for patients with certain medical conditions, such as:

* Myasthenia gravis: an autoimmune disorder that causes muscle weakness and fatigue. In some cases, the thymus gland may contain abnormal cells that contribute to the development of myasthenia gravis. Removing the thymus gland can help improve symptoms in some patients with this condition.
* Thymomas: tumors that develop in the thymus gland. While most thymomas are benign (non-cancerous), some can be malignant (cancerous) and may require surgical removal.
* Myasthenic syndrome: a group of disorders characterized by muscle weakness and fatigue, similar to myasthenia gravis. In some cases, the thymus gland may be abnormal and contribute to the development of these conditions. Removing the thymus gland can help improve symptoms in some patients.

Thymectomy can be performed using various surgical approaches, including open surgery (through a large incision in the chest), video-assisted thoracoscopic surgery (VATS, using small incisions and a camera to guide the procedure), or robotic-assisted surgery (using a robot to perform the procedure through small incisions). The choice of surgical approach depends on several factors, including the size and location of the thymus gland, the patient's overall health, and the surgeon's expertise.

Cholinergic receptors are a type of receptor in the body that are activated by the neurotransmitter acetylcholine. Acetylcholine is a chemical that nerve cells use to communicate with each other and with muscles. There are two main types of cholinergic receptors: muscarinic and nicotinic.

Muscarinic receptors are found in the heart, smooth muscle, glands, and the central nervous system. They are activated by muscarine, a type of alkaloid found in certain mushrooms. When muscarinic receptors are activated, they can cause changes in heart rate, blood pressure, and other bodily functions.

Nicotinic receptors are found in the nervous system and at the junction between nerves and muscles (the neuromuscular junction). They are activated by nicotine, a type of alkaloid found in tobacco plants. When nicotinic receptors are activated, they can cause the release of neurotransmitters and the contraction of muscles.

Cholinergic receptors play an important role in many physiological processes, including learning, memory, and movement. They are also targets for drugs used to treat a variety of medical conditions, such as Alzheimer's disease, Parkinson's disease, and myasthenia gravis (a disorder that causes muscle weakness).

Thymoma is a type of tumor that originates from the thymus gland, which is a part of the immune system located in the chest behind the breastbone. Thymomas are typically slow-growing and often do not cause any symptoms until they have grown quite large or spread to other parts of the body.

Thymomas can be classified into different types based on their appearance under a microscope, such as type A, AB, B1, B2, and B3. These classifications are important because they can help predict how aggressive the tumor is likely to be and how it should be treated.

Symptoms of thymoma may include cough, chest pain, difficulty breathing, or swelling in the face or neck. Thymomas can also be associated with autoimmune disorders such as myasthenia gravis, which affects muscle strength and mobility. Treatment for thymoma typically involves surgical removal of the tumor, often followed by radiation therapy or chemotherapy to help prevent recurrence.

Pyridostigmine Bromide is a medication that belongs to the class of drugs known as cholinesterase inhibitors. It is primarily used in the treatment of myasthenia gravis, a neuromuscular disorder characterized by muscle weakness and fatigue.

Pyridostigmine works by blocking the action of acetylcholinesterase, an enzyme that breaks down acetylcholine, a neurotransmitter essential for muscle contraction. By preventing the breakdown of acetylcholine, pyridostigmine helps to increase its levels at the neuromuscular junction, thereby improving muscle strength and function.

The bromide salt form of pyridostigmine is commonly used because it is more soluble in water, which makes it easier to administer orally as a liquid or tablet. The medication's effects typically last for several hours, and its dosage may be adjusted based on the patient's response and any side effects experienced.

Common side effects of pyridostigmine include nausea, vomiting, diarrhea, increased salivation, sweating, and muscle cramps. In some cases, higher doses of the medication can lead to more severe side effects such as respiratory distress, seizures, or cardiac arrhythmias. Therefore, it is essential to monitor patients closely while they are taking pyridostigmine and adjust the dosage as necessary to minimize side effects and optimize treatment outcomes.

Thymus neoplasms are abnormal growths in the thymus gland that result from uncontrolled cell division. The term "neoplasm" refers to any new and abnormal growth of tissue, also known as a tumor. Thymus neoplasms can be benign or malignant (cancerous).

Malignant thymus neoplasms are called thymomas or thymic carcinomas. Thymomas are the most common type and tend to grow slowly, invading nearby tissues and organs. They can also spread (metastasize) to other parts of the body. Thymic carcinomas are rarer and more aggressive, growing and spreading more quickly than thymomas.

Symptoms of thymus neoplasms may include coughing, chest pain, difficulty breathing, or swelling in the neck or upper chest. Treatment options for thymus neoplasms depend on the type, size, location, and stage of the tumor, as well as the patient's overall health. Treatment may include surgery, radiation therapy, chemotherapy, or a combination of these approaches.

Thymus hyperplasia is a condition where the thymus gland, which is a part of the immune system located in the upper chest beneath the breastbone, becomes enlarged due to an increase in the number of cells. This is different from a tumor, where there is an abnormal growth of cells that can be benign or cancerous.

Thymus hyperplasia can be classified into two types: true hyperplasia and lymphoid hyperplasia. True hyperplasia refers to an increase in the number of thymic epithelial cells, while lymphoid hyperplasia is an increase in the number of lymphocytes (a type of white blood cell) within the thymus gland.

Thymus hyperplasia can occur as a result of various factors, including autoimmune diseases, infections, and certain medications. In some cases, it may not cause any symptoms and may be discovered incidentally during imaging studies or other medical tests. However, in other cases, it may cause symptoms such as cough, chest pain, difficulty breathing, and swallowing.

Treatment for thymus hyperplasia depends on the underlying cause and severity of symptoms. In some cases, no treatment may be necessary, while in others, medications or surgery may be required.

Neonatal Myasthenia Gravis is a condition characterized by muscle weakness in newborn babies, caused by the passive transfer of antibodies from the mother to the fetus. These antibodies target and disrupt the acetylcholine receptors at the neuromuscular junction, which are essential for normal muscle function.

The mother may have myasthenia gravis, an autoimmune disorder that causes muscle weakness due to the production of these harmful antibodies. During pregnancy, these antibodies can cross the placenta and affect the baby's neuromuscular system, leading to symptoms such as weak sucking, poor muscle tone, feeble movements, and respiratory distress.

Neonatal myasthenia gravis is usually temporary and resolves within a few weeks or months as the antibodies are cleared from the baby's circulation. In some cases, treatment with medications that improve neuromuscular transmission, such as anticholinesterase drugs, may be necessary to help manage symptoms until the condition resolves.

Autoantibodies are defined as antibodies that are produced by the immune system and target the body's own cells, tissues, or organs. These antibodies mistakenly identify certain proteins or molecules in the body as foreign invaders and attack them, leading to an autoimmune response. Autoantibodies can be found in various autoimmune diseases such as rheumatoid arthritis, lupus, and thyroiditis. The presence of autoantibodies can also be used as a diagnostic marker for certain conditions.

Blepharoptosis is a medical term that refers to the drooping or falling of the upper eyelid. It is usually caused by weakness or paralysis of the muscle that raises the eyelid, known as the levator palpebrae superioris. This condition can be present at birth or acquired later in life due to various factors such as aging, nerve damage, eye surgery complications, or certain medical conditions like myasthenia gravis or brain tumors. Blepharoptosis may obstruct vision and cause difficulty with daily activities, and treatment options include eyedrops, eye patches, or surgical correction.

Edrophonium is a type of medication called an anticholinesterase agent. It works by blocking the breakdown of acetylcholine, a neurotransmitter in the body that is important for muscle contraction. This results in an increase in the amount of acetylcholine available to stimulate muscle contraction.

Edrophonium is used as a diagnostic aid in the diagnosis of myasthenia gravis, a neuromuscular disorder characterized by muscle weakness and fatigue. It is also used to reverse the effects of non-depolarizing muscle relaxants, which are medications that are sometimes given during surgery to temporarily paralyze muscles.

Edrophonium is administered intravenously (through a vein) and its effects usually begin within 30 seconds to 1 minute after injection and last for about 5 to 10 minutes. Common side effects of edrophonium include sweating, increased salivation, and muscle twitching. More serious side effects, such as seizures or cardiac arrest, can occur but are rare.

It is important to note that edrophonium should only be used under the supervision of a healthcare professional, as it can cause serious side effects if not used properly.

Cholinesterase inhibitors are a class of drugs that work by blocking the action of cholinesterase, an enzyme that breaks down the neurotransmitter acetylcholine in the body. By inhibiting this enzyme, the levels of acetylcholine in the brain increase, which can help to improve symptoms of cognitive decline and memory loss associated with conditions such as Alzheimer's disease and other forms of dementia.

Cholinesterase inhibitors are also used to treat other medical conditions, including myasthenia gravis, a neuromuscular disorder that causes muscle weakness, and glaucoma, a condition that affects the optic nerve and can lead to vision loss. Some examples of cholinesterase inhibitors include donepezil (Aricept), galantamine (Razadyne), and rivastigmine (Exelon).

It's important to note that while cholinesterase inhibitors can help to improve symptoms in some people with dementia, they do not cure the underlying condition or stop its progression. Side effects of these drugs may include nausea, vomiting, diarrhea, and increased salivation. In rare cases, they may also cause seizures, fainting, or cardiac arrhythmias.

Plasmapheresis is a medical procedure where the liquid portion of the blood (plasma) is separated from the blood cells. The plasma, which may contain harmful substances such as antibodies or toxins, is then removed and replaced with fresh plasma or a plasma substitute. The remaining blood cells are mixed with the new plasma and returned to the body. This process is also known as therapeutic plasma exchange (TPE). It's used to treat various medical conditions including certain autoimmune diseases, poisonings, and neurological disorders.

Neostigmine is a medication that belongs to a class of drugs called cholinesterase inhibitors. It works by blocking the breakdown of acetylcholine, a neurotransmitter in the body, leading to an increase in its levels at the neuromuscular junction. This helps to improve muscle strength and tone by enhancing the transmission of nerve impulses to muscles.

Neostigmine is primarily used in the treatment of myasthenia gravis, a neurological disorder characterized by muscle weakness and fatigue. It can also be used to reverse the effects of non-depolarizing muscle relaxants administered during surgery. Additionally, neostigmine may be used to diagnose and manage certain conditions that cause decreased gut motility or urinary retention.

It is important to note that neostigmine should be used under the close supervision of a healthcare professional due to its potential side effects, which can include nausea, vomiting, diarrhea, increased salivation, sweating, and muscle cramps. In some cases, it may also cause respiratory distress or cardiac arrhythmias.

I believe you may be mistaken when referring to "torpedo" in the context of medicine. The term "torpedo" is not typically used as a medical definition. Instead, it is a term that has various meanings in different fields such as physics, military, and anatomy (in relation to electric fishes).

However, if you are referring to the use of "torpedo" in the context of neuromuscular disorders, it may refer to a type of treatment called "neuromuscular electrical stimulation" or NMES. In this case, the term "torpedo" is used metaphorically to describe the electrical impulse that is delivered to the muscle to cause a contraction. This can be used as a therapeutic intervention for various neuromuscular conditions such as muscle weakness or paralysis.

If you have any further questions, please let me know and I will do my best to assist you!

The neuromuscular junction (NMJ) is the specialized synapse or chemical communication point, where the motor neuron's nerve terminal (presynaptic element) meets the muscle fiber's motor end plate (postsynaptic element). This junction plays a crucial role in controlling muscle contraction and relaxation.

At the NMJ, the neurotransmitter acetylcholine is released from the presynaptic nerve terminal into the synaptic cleft, following an action potential. Acetylcholine then binds to nicotinic acetylcholine receptors on the postsynaptic membrane of the muscle fiber, leading to the generation of an end-plate potential. If sufficient end-plate potentials are generated and summate, they will trigger an action potential in the muscle fiber, ultimately causing muscle contraction.

Dysfunction at the neuromuscular junction can result in various neuromuscular disorders, such as myasthenia gravis, where autoantibodies attack acetylcholine receptors, leading to muscle weakness and fatigue.

Diplopia is a medical term that refers to the condition where a person sees two images of a single object. It is commonly known as double vision. This can occur due to various reasons, such as nerve damage or misalignment of the eyes. Diplopia can be temporary or chronic and can affect one or both eyes. If you're experiencing diplopia, it's essential to consult an eye care professional for proper evaluation and treatment.

The thymus gland is an essential organ of the immune system, located in the upper chest, behind the sternum and surrounding the heart. It's primarily active until puberty and begins to shrink in size and activity thereafter. The main function of the thymus gland is the production and maturation of T-lymphocytes (T-cells), which are crucial for cell-mediated immunity, helping to protect the body from infection and cancer.

The thymus gland provides a protected environment where immune cells called pre-T cells develop into mature T cells. During this process, they learn to recognize and respond appropriately to foreign substances while remaining tolerant to self-tissues, which is crucial for preventing autoimmune diseases.

Additionally, the thymus gland produces hormones like thymosin that regulate immune cell activities and contribute to the overall immune response.

I'm happy to help! "Rats, Inbred Lew" is a specific strain of laboratory rats that have been inbred for research purposes. The "Lew" part of the name refers to the location where they were first developed, the Lewis Institute in Lake Bluff, Illinois, USA.

Inbreeding is a process of mating closely related individuals over many generations to create a genetically homogeneous population. This results in a high degree of genetic similarity among members of the strain, making them ideal for use as experimental models because any differences observed between individuals are more likely to be due to the experimental manipulation rather than genetic variation.

Inbred Lew rats have been widely used in biomedical research, particularly in studies related to hypertension and cardiovascular disease. They exhibit a number of unique characteristics that make them useful for these types of studies, including their susceptibility to developing high blood pressure when fed a high-salt diet or given certain drugs.

It's important to note that while inbred strains like Lew rats can be very useful tools for researchers, they are not perfect models for human disease. Because they have been bred in a controlled environment and selected for specific traits, they may not respond to experimental manipulations in the same way that humans or other animals would. Therefore, it's important to interpret findings from these studies with caution and consider multiple lines of evidence before drawing any firm conclusions.

Autoimmune diseases are a group of disorders in which the immune system, which normally protects the body from foreign invaders like bacteria and viruses, mistakenly attacks the body's own cells and tissues. This results in inflammation and damage to various organs and tissues in the body.

In autoimmune diseases, the body produces autoantibodies that target its own proteins or cell receptors, leading to their destruction or malfunction. The exact cause of autoimmune diseases is not fully understood, but it is believed that a combination of genetic and environmental factors contribute to their development.

There are over 80 different types of autoimmune diseases, including rheumatoid arthritis, lupus, multiple sclerosis, type 1 diabetes, Hashimoto's thyroiditis, Graves' disease, psoriasis, and inflammatory bowel disease. Symptoms can vary widely depending on the specific autoimmune disease and the organs or tissues affected. Treatment typically involves managing symptoms and suppressing the immune system to prevent further damage.

Nicotinic receptors are a type of ligand-gated ion channel receptor that are activated by the neurotransmitter acetylcholine and the alkaloid nicotine. They are widely distributed throughout the nervous system and play important roles in various physiological processes, including neuronal excitability, neurotransmitter release, and cognitive functions such as learning and memory. Nicotinic receptors are composed of five subunits that form a ion channel pore, which opens to allow the flow of cations (positively charged ions) when the receptor is activated by acetylcholine or nicotine. There are several subtypes of nicotinic receptors, which differ in their subunit composition and functional properties. These receptors have been implicated in various neurological disorders, including Alzheimer's disease, Parkinson's disease, and schizophrenia.

Ocular motility disorders refer to a group of conditions that affect the movement of the eyes. These disorders can result from nerve damage, muscle dysfunction, or brain injuries. They can cause abnormal eye alignment, limited range of motion, and difficulty coordinating eye movements. Common symptoms include double vision, blurry vision, strabismus (crossed eyes), nystagmus (involuntary eye movement), and difficulty tracking moving objects. Ocular motility disorders can be congenital or acquired and may require medical intervention to correct or manage the condition.

Eye manifestations refer to any changes or abnormalities in the eye that can be observed or detected. These manifestations can be related to various medical conditions, diseases, or disorders affecting the eye or other parts of the body. They can include structural changes, such as swelling or bulging of the eye, as well as functional changes, such as impaired vision or sensitivity to light. Examples of eye manifestations include cataracts, glaucoma, diabetic retinopathy, macular degeneration, and uveitis.

Ophthalmoplegia is a medical term that refers to the paralysis or weakness of the eye muscles, which can result in double vision (diplopia) or difficulty moving the eyes. It can be caused by various conditions, including nerve damage, muscle disorders, or neurological diseases such as myasthenia gravis or multiple sclerosis. Ophthalmoplegia can affect one or more eye muscles and can be partial or complete. Depending on the underlying cause, ophthalmoplegia may be treatable with medications, surgery, or other interventions.

Electromyography (EMG) is a medical diagnostic procedure that measures the electrical activity of skeletal muscles during contraction and at rest. It involves inserting a thin needle electrode into the muscle to record the electrical signals generated by the muscle fibers. These signals are then displayed on an oscilloscope and may be heard through a speaker.

EMG can help diagnose various neuromuscular disorders, such as muscle weakness, numbness, or pain, and can distinguish between muscle and nerve disorders. It is often used in conjunction with other diagnostic tests, such as nerve conduction studies, to provide a comprehensive evaluation of the nervous system.

EMG is typically performed by a neurologist or a physiatrist, and the procedure may cause some discomfort or pain, although this is usually minimal. The results of an EMG can help guide treatment decisions and monitor the progression of neuromuscular conditions over time.

Lambert-Eaton Myasthenic Syndrome (LEMS) is a rare autoimmune disorder characterized by muscle weakness and fatigability. It is caused by the presence of antibodies against voltage-gated calcium channels (VGCC) in the neuromuscular junction, which disrupts the normal transmission of signals between nerves and muscles.

The symptoms of LEMS include proximal muscle weakness, which may affect the legs more than the arms, and autonomic dysfunction such as dry mouth and constipation. The weakness tends to improve with exercise but worsens after periods of rest. In some cases, LEMS can be associated with cancer, particularly small cell lung cancer.

Diagnosis of LEMS typically involves a combination of clinical evaluation, electromyography (EMG) studies, and blood tests to detect VGCC antibodies. Treatment may include medications such as pyridostigmine, which improves neuromuscular transmission, or intravenous immunoglobulin and plasma exchange, which help to reduce the immune response. In cases where LEMS is associated with cancer, treatment of the underlying malignancy can also improve muscle strength and function.

A motor endplate, also known as the neuromuscular junction, is the site where a motor neuron's axon terminal synapses with a muscle fiber. It is a specialized chemical synapse that allows for the transmission of electrical signals from the nervous system to the skeletal muscles, resulting in muscle contraction. The motor endplate is composed of several structures including the presynaptic membrane, which contains neurotransmitter-filled vesicles, and the postsynaptic membrane, which contains numerous nicotinic acetylcholine receptors. When an action potential reaches the axon terminal, it triggers the release of acetylcholine into the synaptic cleft, where it binds to receptors on the postsynaptic membrane and causes the opening of ion channels, leading to the generation of an endplate potential that can trigger muscle contraction.

A muscle is a soft tissue in our body that contracts to produce force and motion. It is composed mainly of specialized cells called muscle fibers, which are bound together by connective tissue. There are three types of muscles: skeletal (voluntary), smooth (involuntary), and cardiac. Skeletal muscles attach to bones and help in movement, while smooth muscles are found within the walls of organs and blood vessels, helping with functions like digestion and circulation. Cardiac muscle is the specific type that makes up the heart, allowing it to pump blood throughout the body.

Bungarotoxins are a group of neurotoxins that come from the venom of some species of elapid snakes, particularly members of the genus Bungarus, which includes kraits. These toxins specifically bind to and inhibit the function of nicotinic acetylcholine receptors (nAChRs), which are crucial for the transmission of signals at the neuromuscular junction.

There are three main types of bungarotoxins: α, β, and κ. Among these, α-bungarotoxin is the most well-studied. It binds irreversibly to the nicotinic acetylcholine receptors at the neuromuscular junction, preventing the binding of acetylcholine and thus blocking nerve impulse transmission. This results in paralysis and can ultimately lead to respiratory failure and death in severe cases.

Bungarotoxins are widely used in research as molecular tools to study the structure and function of nicotinic acetylcholine receptors, helping us better understand neuromuscular transmission and develop potential therapeutic strategies for various neurological disorders.

Antibodies are proteins produced by the immune system in response to the presence of a foreign substance, such as a bacterium or virus. They are capable of identifying and binding to specific antigens (foreign substances) on the surface of these invaders, marking them for destruction by other immune cells. Antibodies are also known as immunoglobulins and come in several different types, including IgA, IgD, IgE, IgG, and IgM, each with a unique function in the immune response. They are composed of four polypeptide chains, two heavy chains and two light chains, that are held together by disulfide bonds. The variable regions of the heavy and light chains form the antigen-binding site, which is specific to a particular antigen.

Azathioprine is an immunosuppressive medication that is used to prevent the rejection of transplanted organs and to treat autoimmune diseases such as rheumatoid arthritis, lupus, and inflammatory bowel disease. It works by suppressing the activity of the immune system, which helps to reduce inflammation and prevent the body from attacking its own tissues.

Azathioprine is a prodrug that is converted into its active form, 6-mercaptopurine, in the body. This medication can have significant side effects, including decreased white blood cell count, increased risk of infection, and liver damage. It may also increase the risk of certain types of cancer, particularly skin cancer and lymphoma.

Healthcare professionals must carefully monitor patients taking azathioprine for these potential side effects. They may need to adjust the dosage or stop the medication altogether if serious side effects occur. Patients should also take steps to reduce their risk of infection and skin cancer, such as practicing good hygiene, avoiding sun exposure, and using sunscreen.

Muscle weakness is a condition in which muscles cannot develop the expected level of physical force or power. This results in reduced muscle function and can be caused by various factors, including nerve damage, muscle diseases, or hormonal imbalances. Muscle weakness may manifest as difficulty lifting objects, maintaining posture, or performing daily activities. It is essential to consult a healthcare professional for proper diagnosis and treatment of muscle weakness.

'Electrophorus' is a scientific term that refers to a genus of electric fishes found in the Amazon River basin in South America. The name is most commonly associated with one species in particular, Electrophorus electricus, which is more popularly known as the electric eel. Despite its common name, the electric eel is not a true eel but rather a knifefish, related to catfishes and carps.

The term 'Electrophorus' comes from the Greek words "electron," meaning amber or electron (with a nod to its electrical properties), and "pherein," meaning to carry or bear. This name is fitting for the electric eel, as it has the remarkable ability to generate strong electric fields that it uses for hunting, navigation, and defense.

Electric eels possess specialized electric organs in their body, which are made up of electrocytes - cells that function like tiny batteries when stimulated. By stacking thousands of these electrocytes together, the electric eel can produce powerful electrical discharges reaching up to 600 volts and 1 ampere of current, enough to stun or even kill prey and deter potential predators.

In summary, 'Electrophorus' is a medical definition for a genus of electric fishes, with the most well-known species being the electric eel (Electrophorus electricus). These unique creatures have the ability to generate strong electric fields using specialized electric organs, which they use for hunting, navigation, and defense.

Neuromuscular junction diseases are a group of disorders that affect the functioning of the neuromuscular junction, which is the site where nerve impulses are transmitted to muscles. These diseases are characterized by muscle weakness and fatigue, and can be caused by various factors such as autoimmune disorders, genetic mutations, or toxins.

Examples of neuromuscular junction diseases include myasthenia gravis, Lambert-Eaton myasthenic syndrome (LEMS), congenital myasthenic syndromes (CMS), and botulism. Myasthenia gravis is an autoimmune disorder that causes the immune system to attack the receptors in the neuromuscular junction, leading to muscle weakness and fatigue. LEMS is a rare autoimmune disorder that affects the nerve endings at the neuromuscular junction, causing muscle weakness and decreased reflexes.

Congenital myasthenic syndromes are genetic disorders that affect the functioning of the neuromuscular junction from birth, leading to muscle weakness and fatigue. Botulism is a rare but serious condition caused by the ingestion of botulinum toxin, which can lead to paralysis of the muscles due to interference with nerve impulse transmission at the neuromuscular junction.

Treatment for neuromuscular junction diseases may include medications such as cholinesterase inhibitors, immunosuppressive drugs, or plasma exchange therapy, depending on the specific diagnosis and severity of the condition.

The oculomotor muscles are a group of extraocular muscles that control the movements of the eye. They include:

1. Superior rectus: This muscle is responsible for elevating the eye and helping with inward rotation (intorsion) when looking downwards.
2. Inferior rectus: It depresses the eye and helps with outward rotation (extorsion) when looking upwards.
3. Medial rectus: This muscle adducts, or moves, the eye towards the midline of the face.
4. Inferior oblique: The inferior oblique muscle intorts and elevates the eye.
5. Superior oblique: It extorts and depresses the eye.

These muscles work together to allow for smooth and precise movements of the eyes, enabling tasks such as tracking moving objects, reading, and maintaining visual fixation on a single point in space.

Plasma exchange, also known as plasmapheresis, is a medical procedure where the liquid portion of the blood (plasma) is separated from the blood cells. The plasma, which may contain harmful substances such as antibodies, clotting factors, or toxins, is then removed and replaced with fresh plasma or a plasma substitute. This process helps to remove the harmful substances from the blood and allows the body to replenish its own plasma with normal components. Plasma exchange is used in the treatment of various medical conditions including autoimmune diseases, poisonings, and certain types of kidney diseases.

Immunoglobulin G (IgG) is a type of antibody, which is a protective protein produced by the immune system in response to foreign substances like bacteria or viruses. IgG is the most abundant type of antibody in human blood, making up about 75-80% of all antibodies. It is found in all body fluids and plays a crucial role in fighting infections caused by bacteria, viruses, and toxins.

IgG has several important functions:

1. Neutralization: IgG can bind to the surface of bacteria or viruses, preventing them from attaching to and infecting human cells.
2. Opsonization: IgG coats the surface of pathogens, making them more recognizable and easier for immune cells like neutrophils and macrophages to phagocytose (engulf and destroy) them.
3. Complement activation: IgG can activate the complement system, a group of proteins that work together to help eliminate pathogens from the body. Activation of the complement system leads to the formation of the membrane attack complex, which creates holes in the cell membranes of bacteria, leading to their lysis (destruction).
4. Antibody-dependent cellular cytotoxicity (ADCC): IgG can bind to immune cells like natural killer (NK) cells and trigger them to release substances that cause target cells (such as virus-infected or cancerous cells) to undergo apoptosis (programmed cell death).
5. Immune complex formation: IgG can form immune complexes with antigens, which can then be removed from the body through various mechanisms, such as phagocytosis by immune cells or excretion in urine.

IgG is a critical component of adaptive immunity and provides long-lasting protection against reinfection with many pathogens. It has four subclasses (IgG1, IgG2, IgG3, and IgG4) that differ in their structure, function, and distribution in the body.

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