Botulinum Toxin

Botulinum toxin is a potent toxin. It is derived from botulinum clostridium botulinum.It is a poisonous biological substance and it acts as a neurotoxin. It binds to the nerve endings at the point, the nerve joins a muscle. It blocks the realizing of the principle neurotransmitter. It is called acetylcholine. Acetylcholine at the neuromuscular junction prevent the muscle from antracting.Tise course to weakness and paralysis of the muscle. This blackase of releasing acetylcholine is irreversible. Sprouting of nerve terminals and the formation of new synaptic ontracts, the function can be recorrecd.It takes 2 to 3 months.

There are many types of Botulinum toxin. They are named as type A, B, C, D, E, F and G different strand for bacteria produce them and defined by the international strands for clostridium botulinum.The seven types of designated A to G distinct neurotoxins have a similar molecular weight and structure consisting of a heavy chain and light chain, joined by disulfide bond. All the types act in a similar manner. The toxin is heat labile. If it is heated at 800 C for about 10 minutes or more it can be destroyed. (1).

Very small amounts of botulinum toxin can be caused botulism. There are two ways of it By ingesting the toxin itself (food borne botulism) as in produce and release the toxin in the body (infectious botulism).The infection may occur in the intensive (intestinal botulism) as in newborn, or deep within a wound (wound botulism) only the Types A, B, E and F are known to cause botulism in human all the types.
As first line therapy Botulinum toxin is used for some muscular disorders. It is efficacious in treating hypersecretory and some point syndromes. It has a god safety profile. A number of conditions have been evaluated in treating. There is no obvious effective or benhicial treat mint yet. The use of Botulinum toxin will be increased with the grater acceptance. For the physicians the understanding of pharmacology and potential adverse effects are essential. When prevents having or who are benefited from Botulinum from Botulinum therapy.(2)

Clostridium Botulinum

A group of bacteria commonly found in soil is named as clostridium Botulinum. It is strictly anaerobic gram negative rod shaped bacillus. It is motile with meretricious flagella and has spores. They are oval and sub terminal until they are exposed to conditions that can be supported to their growth, spores’ abow them to survive in dormant state. The exposed conditions can be found in vegetables, fruits, leaves, silage, and manure, the mud in the lakes and the mud in the sea. The optimum growth temperature is about 350c but at 1- 50 c temperature some strains have been shown to grow and produce toxin.

The nature of clostridium Botulinum is its ability to produce a potent neuron toxin in food. The resistance of its spores to inactivation combine to male a formidable pathogen of humans and a range of animals and birds. When boiling in water for several hours the spores of some stains with stand. When they are heated up to 1200 c for 5 minutes they are destroyed. Spore of type E strains are much less heat resistance. In the causation of botulism insufficient heating in the presence of preserving food is an important factor and great care must be taken in canning factories to ensure that adequate heating is achieved in all part of the can. in the food processing the resistance of the spores to radiation is a special relevance.(3)

(1)The structure of Botulinum Toxin and Mechanism of Toxic Action;

All outline toxins are synthesized as single-chain polypeptides with a molecular weight of
Approximately 150KDa.The complete amino acid sequences for the various serotypes are known and region of sequence homology among the serotypes suggest that all employ similar mechanism of biological action..In the single- chain form, toxins have relatively little potency as neurotoxins. Neurotoxic activation requires a tow-step modification in the tertiary structure of the protein.In the first step ,the parent chain is cleaved between amino acids 448 and 449.The result is one light chain(amino acids 1-448,approx 100KDa) and one heavy chain ( amino acid 449-1295, approx.100KDa) connected via disulfide bond. The light chain is associated with one atom of zinc..In this form, the toxin enters the axon terminal. The second activating step, disulfide reduction, occurs only after internalization by the target cell.

Botulinum neurotoxins are potent blockers of synaptic transmission in peripheral cholinergic nervous system synapses; thereby causing paralysis .Resent studies on the biochemical dissection of the components involved in the fusion of secretary vesicles with the plasma membrane have set outline toxins at center of this process. Outline toxins are Zn+2-metalloproteases that selectively cleave proteins implicated in fusion process and accordingly, block neurotransmitter release Into the synaptic cleft .Outline toxin A, E and C proteolyses the plasma membrane associated proteins SNAP-25 and outline toxin C cleave still syntax in .Outline toxins B, D, F, and G proteolyses synaptobrevin, a vesicle-associated membrane protein, also known as VAMP. The protease activity of the toxins is confined ton there light chains .Botulinum toxins have an inherent propensity to insert into membranes, especially at acidic PH. This property is compatible with ion channel activity observed. When outline toxins B, C, D, and E are reconstituted in lipid bilayers A novel combination of theoretical approaches was exploited to predict which amino acid residues of various botulinum neurotoxin serotypes participate in forming ion channels Image reconstruction analysis of electron micrographs of outline toxin inserted in membrane suggests the occurrence of a tetramer as the structural entity underling the outline toxin channel (4)

Preparation of botulinum toxin

Botulinum toxin is harvested from a culture medium after fermentation of producing strain of a botulinum c toxin. It is extracted, precipitated, purified and finally crystallized with ammonium sulfate. Toxin A should be diluted with preservation free saline. It should be diluted with preservative free saline. It should be prepared with in four hours of its reconstitution. The solution should be include pH 4.2-6.8 for stamility. Its temperature should be less than 20c .This solution can be inactivated easily.

Scientific background-botulinum toxin

Botulinum toxin is a potent neurotoxin that block cholinergic nerve terminals, symptoms of botulism include cessation of sweating. Therefore, intracutaneous injections have been investigation as a treatment of gustatory hyperhidrosis and focal primary hyperhidrosis, most frequently involving the axillae or palms. Askew and colleagues reported on the outcomes of 19 patients with gustatory hyperhidrosis treated with botulinum toxin injected with every 4 cm 2 of involved skin. (20In all cases, gustatory sweating ceased within two days, with a mean duration of effect of 17 months. There is a considerable body of published literature regarding outline toxin injecting for the treatment of auxiliary hyperhidrosis, all of which substantiates its effectiveness. Two of these were double-blind, randomized trials that de palmer hyperhhidrosis. The drawback of this approach is the need for repeated injections, which has led some to consider surgical approaches to treatment.(5)

Toxicity and Botulism

Very small amount of Botulism toxin can lead to botulism, a descending paralysis and often affecting the autonomic system. .Clinical features of Botulism;
Food born botulism is caused by ingestion of performed toxin produced in food by c botulism. The most frequent source in home-canned foods, in which spores that survive an inadequate cooking and canning process germinate and produce toxin in the anaerobic environment of the canned food. In the event of intentional food borne poisoning with botulism toxin, the signs and symptoms developing after ingestion would probably resemble those of naturally occurring food borne botulism. If aerosolized toxin was inhaled the incubation period might be slightly longer and gastrointestinal symptoms might not occur The clinical syndrome of food borne botulism is dominated by neurological symptoms resulting (cont.p.16-Botox) (Botox-fromp.15) from a toxin-induced block of the voluntary motor and autonomic cholinergic junctions. With food borne botulisum, symptoms begin within 6 hours to 2 weeks (most commonly between 12 and 36 hors ) after eating toxin-containing food. Although the syndrome is similar for each toxin type ,type A toxin has been associated with more severe disease and a higher fatality rate than type or type E toxin.Symptoms from any toxin type may range from subtle motor `weakness or cranial nerve palsies to rapid respiratory arrest. The initial symptoms of food borne botulism may be gastrointestinal and can include nausea ,vomiting ,abdominal cramps ,or diarrhea, after the onset of neurology symptoms, constipation is more typical. Dry mouth ,blurred vision, and diplopia are usually the earliest neurologic symptoms. These initial symptoms may be followed by dysphonia ,dysarthria, dysphagia, and peripheral muscle weakness symmetric decending paralysis is characteristic he of botulism paralysis begins with the cranial nerves ,the upper extremities in a proximal-to-distal pattern. Onset usually occurs 18 to 36 hours after exposure . In severe cases extensive respiratory muscle paralysis leads to ventilator failure and death unless supportive care is provided. Patients have required ventilator support for up to 7 months before the return of muscular function, but ventilator support is most commonly needed for 2 to 8 weeks. Clinical recovery generally occurs over weeks to months; electron microscopic evidence suggests that clinical recovery correlates with the formation of new presynaptic end plates and neuromuscular junctions (26). Before mechanical ventilation and intensive supportive care. Up to 60% of patient’s deed. Death now occurs in 5% to 10% of cases of food borne botulism ; early deaths result from a failure to recognize the severity of disease, whereas deaths after 2 weeks result from complications of long- term mechanical ventilator management .
The demonstration of the toxin in serum is definitive, but the test may be negative, particularly in infant or wound botulism. The demonstration of toxin or the organism in vomit, gastric fluid, or stool is strongly suggestive, because intestinal carriage is rare. Isolation of the organism from food without the toxin is insufficient for the diagnosis. Wound cultures showing the organism are suggestive. Cerebrospinal fluid examination is normal, unless dehydration or starvation are present. The electromyography may demonstrate a defect in neuromuscular transmission, and a typical finding is facilitation (potentiation) of the evoked muscle action potential at high frequency stimulation (6)

Food-born:botulism After the ingestion of contaminated food, the illness varies from mild, which needs no medical attention; to severe disease, which can result in death in less than 24 hours. The incubation period is usually 18 to 36 hours, but may range from a few hours to many days depending on the amount of toxin ingested. The shorter the incubation period, the more severe the clinical manifestations are. The onset of the symptoms is characterized by cranial nerve involvement, mainly in those innervating the bulbar musculature. This results in the appearance of diplopia, difficulty in close-range focusing, dysphonia, dysartria, and dysphagia. The weakness progresses rapidly to involve the neck, shoulder, thorax, abdomen, arms, and legs. Nausea, vomiting, and abdominal pain may appear before or after the onset of paralysis. The weakness is usually symmetric, but may be asymmetric as well. Autonomic involvement may cause dizziness, blurred vision, dry mouth, very dry and sore throat, ileus, and salivary retention. The tendon reflexes may be normal, but are usually diminished. The pupillary reflexes are depressed, and the pupils may be fixed and dilated. The patient is alert and conscious, and mentation is spared. The gag reflex is also diminished or abolished. Typically there is no fever, but the descending paralysis also attacks the respiratory muscles. This, along with bulbar paralysis and secondary infections, is the main cause of death together.(7)
Wound botulism : This form of botulism appears after a wound is contaminated by the spores of C. botulinum, which is found in soil. The spores then germinate into vegetative forms that produce toxin The period of incubation for this form of botulism is longer, ranging from 4 to 14 days, with a median average of 10 days. The clinical manifestations are identical to the food-borne, botulism with the exception of gastrointestinal symptoms. The illness occurs even after preventative antibiotics are administered.(8)
Infant : This usually differs in apparent initial symptoms of the illness, simply because infants cannot verbalize them. Almost invariably, the first indication of illness is constipation, defined as three or more days without defecation. Parents usually notice lethargy, listlessness, poor appetite, a weak cry, and diminished movements. Dysphagia may be seen as “drooling” from the mouth. Gag, suck, and corneal reflexes diminish as paralysis advances. Oculomotor palsies also occur. The pupillary reflex may be spared until the child is severely ill. Loss of head control is a prominent sign, and respiratory arrest may occur suddenly.(9)
Adult-infant: In this form of botulism the clinical manifestations are the same as mentioned above. The disease affects adults and children, who are older than 12 months old, by the C. botulinum colonization of the intestines. It is there that the disease-causing toxin is produced.
Diagnosis
botulism should be suspected in any mentally intact patient who has an afebrile, descending paralysis without sensory manifestations. In these cases analysis (searching for C. botulinum or it toxin ) of serum, stool, gastric contents or vomit, food, and wounds is necessary.(10)
Treatment
Any patient suspected of having botulism should be hospitalized and monitored closely-both clinically and by spirometry, pulse oximetry, and measurement of arterial blood gases to prevent respiratory failure. Intubation and mechanical ventilation should be considered when vital capacity falls below 30% of prediction-especially when paralysis is progressing rapidly and hypercarbia is present.
In food-borne illness, trivalent antitoxin should be administered as soon as possible after material for laboratory analysis is obtained. Since toxin may persist in the blood for extended periods, the antitoxin should be given irrespectively to the time of progression of the illness. One should not wait for laboratory confirmation before initiating treatment . After testing for horse serum hypersensitivity, two vials of trivalent antitoxin, containing 7500I of type A, 5500I of type B, and 8500I of type E should be administered; one intravenously, and another intramuscularly. This dose may be repeated 2 to 4 hours later. Hypersensitivity reactions may occur since the antitoxin is made of horse serum. Anaphylaxis and serum sickness are feared reactions, and allergic patients should be desensitized prior to the administration. If there is no ileus, cathartics and enemas should be given to eliminate toxin from the gut. Emetics and gastric lavage are also used if the ingestion of the contaminated food has been recent within a few hours. Other therapeutic considerations are the use of guanidine hydrochloride (15 to 50mg/kg daily), to enhance acetylcholine release, and antibiotics (penicillin), to eliminate the bacteria from the intestine.(11)

Botulinism toxin Use as.

Introduction :- The role of botulinum toxin as a therapeutic agent for several conditions is expanding. We sought to determine if botulinum toxin is safe and effective in treating patients with cervical dystonia and maxillofacial conditions. Our purpose was to establish a safety and efficacy profile to determine whether or not this treatment may be used prophylactically in patients undergoing dental implant therapy,
Methods- We performed a systematic search of the literature to identify randomized clinical trials evaluating patient treated with botulinum as an adjunct to dental implant
therapy, maxillofacial conditions including TM disorders (TMD) and cervical dystonia.

Results: – For randomized controlled trials (RCTS) met our search criteria in the area of cervical dystonia and chronic facial pain. No RCTS were identified evaluating dental implant therapy. Patient with chronic facial pain improved significantly from baseline in terms of pain compared to placebo. Rates of adverse events were less than 1% .

Conclusion; Botulinum toxin appears relatively safe and effective in treating cervical dystonia and ohronic facial pain associated with masticatory hyperactivity. No literature exists evaluating its use in dental implantology. Randomized clinical trials are warranted to determine its safety and efficacy in dental implantology and other maxilliaryfacial conditions such as bruxism
Migraine is a chronic headache disorder manifesting in attacks lasting 4-72 hours .Characteristics of headache are unilateral location pulsative quality, moderate , or severe intensity ,aggravation by routing physical activity ,and association with nausea ,photophobia and phonophobia. The migraine aura is a complex of neurological symptoms, which occurs just before or at the onset of migraine headache. Botulinum toxin A represents a completely new option for patients with chronic pain conditions. Numerous retrospective open-label chart reviews and 4 double-blind, placebo –controlled studies have demonstrated that botulinum toxin type A is significantly effective in migraine prophylaxis and reduces the frequency, severity, and disability associated with migraine headache. Studies have generally reported a good and consistent efficacy. The differential therapeutic use of botulinum toxin appears to be worth attempting in migraine patients with the following characteristic features.

1. muscular stress as migraine trigger. e.g. in craniocervical dystonia, pericranial painful muscular trigger points or tender points ,oromandibular dysfunctions.
2. concurrent chronic tension.- type headache with the aggravating factors of muscular stress or oromandibular dysfunction.
3. chronic migraine with frequent migraine attacks on more than 15 days per month for longer than three months and if other therapeutic options have been either ineffective of have not been tolerated. The use of agent does not cause CNS side effects. Migraine patients in particular , often suffer the drugs used , frown fatigue, dizziness, reduced
concentration , loss of appetite, weight gain, hairless and changes in libido. These sideeffects are not known in association with botulinum toxin A. To date neither organic damage nor allergic complications have been reported. Thus both the tolerability and the safety of this therapeutic measure are high. The mode of action by which outline toxin is effective in migraine prophylaxis is not fully understood and is order investigation .
Tension type Headaches;
Tension type headaches are described as a band-like pain that encompasses the frontal to occipital region. Associated with this type of headache ,there m ay be an associated cervical Myofacial pain syndrome (MPS).MPS is characterized by acute pain in one or more trigger point located within the affected muscles. The goal for treatment of these conditions is to provide relaxation to the affected muscles. Standard therapies have included non-steroidal anti-inflammatory drugs, corticosteroids, and antidepressants, injections of local anesthetic in combination with or without corticosteroids. Additional therapies have included dry needing and physical therapy.

Migraines; Recently botulinum toxin has come into vague as a treatment for facial wrinkles, it was discovered that people who suffered from migraines had a decrease in the frequency and severity of these types of headaches. Since then several authors have described the treatment of migraines with Botulinum toxin.
Botulinum toxin has demonstrated its efficacy in a number of conditions associated with dysregulated muscle contractions. In addition to the muscle relaxation, secondary effects include release of entrapped nerve and pain relief physiotherapy associated with this treatment will assist in breaking the cycle of pain and spasm. This combination of effects is designed to achieve neuromuscular re – education improving posture & restoring normal muscle and tendon movement.

(1)Tennis elbow (lateral epicondylitis) is a frequent cause of elbow pain. Repetitive use of arm, especially repeated extension of the wrist and elbow causes strain and inflammation of muscles and tendons. These movements are common in many activities besides tennis. Commonly used treatments include nonsteroidal anti-inflammatory drugs physical therapy corticosteroid injections and surgery. Researchers do not know if any of these therapies are really effective because tennis elbow eventually improves by itself. Botulinum toxin (Botox) is another potential treatment. Botulinum toxin is a protein produced by bacteria that blocks conduction of nerve impulses. It may reduce pain by blocking the nerve impulses that cause painful muscle spasms small studies suggest that botulinum toxin is an effective treatment for tennis elbow but studies are not definitive.
References
(1) Hackett R, kam Pc, Botulinum toxin: pharmacology and clinical developments, a literature review. Medic hem 3rd July 2007
(2) Animals of internal Medicine.
Established in 1927 by the .American collage of physicians
. Botulinum toxin as a treatment for Tennis Elbow.
6, Dec, 2005
(3) J Cutan Med Surg . 2005 Jan 6; {Epub ahead of print

(4) Nature, 2004 Dec 16, 432(7019), 925 – 9 Epub 2004 Dec 12
(5) Botulinum toxin in migrane prophylaxis Gobel H
Neurologists-Verhaltenseidizinische Scherzklini Kiel ,Heikendorfer Weg 9-27,
(6) Department of Epidemiology, Military Medical Academy, Hradec Kralove, Czech Republic.
The ASA Newsletter
www.asanltr.com/ newsletter/ 02-1/ articles/ Botulinum htm-371 cached

(7).ABUTYN, Elias. In: ISSELBACHER, Kurt; BRAUNWALD, Eugene et al. Harrison`s Principles of Internal Medicine. 13th ed. McGraw-Hill Inc, 1994.

(8).ADAMS, Raymond; VICTOR, Maurice & ROPPER, Allan H. Principles of Neurology. 6th ed. McGraw-Hill Inc, 1997.

(9).ARNON, Stephen S. botulism In: BEHRMAN, Richard E; KLIEGMAN, Robert M & ARVIN, Ann M. Nelson Textbook of Pediatrics. 15th ed. W.B. Saunders Co., 1996.

(10).BARTLETT, John G . In: BENNET, J Claude & PLUM, Fred. Cecil Textbook of Medicine. 20th ed. W.B. Saunders Co., 1996.

(11) Trakads Ramachandran, MD, chief Department of Neurology, university of Newyork
Medicine
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• RUM 2006/3377.