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Collagen Periurethral Injection

Collagen periurethral injection

Definition

Collagen periurethral injection is a procedure in which collagen is injected around the urethra and bladder neck as a treatment for stress incontinence in women.


Purpose

The bladder and urethra are supported by muscles, ligaments, and connective tissues around the base of the bladder. This support prevents the leakage of urine, along with the watertight seal provided by the urethra. As a result of pregnancy, childbirth, and aging, or damage by scarring from surgery or radiotherapy, these structures may become damaged or weakened, thus causing stress incontinence, meaning an involuntary loss of urine that occurs during physical activity such as coughing, sneezing, laughing, or exercise .

The injection of bulking agents such as collagen around the urethra aims to improve the lost support of the bladder and urethra. The substance most commonly used for injection is collagen; other bulking agents are being developed, for example, a silicon base suspended in a viscous gel called Macroplastique. Teflon paste, introduced in the 1970s, initially gave good results, but was discontinued after reported problems with excessive scarring and with the migration of Teflon particles to other tissues in the body. The collagen used in the procedure comes from the cartilage of cattle and has been extensively sterilized to produce a viscous paste for injection. There is no risk of bovine spongiform encephalopathy (BSE) transmission because the processing of the paste destroys any bacterial or viral particles.


Description

The collagen periurethral injection procedure is quick, and usually over within 1520 minutes. No incisions are made, meaning that it can be carried out using a local anesthetic or a regional anesthetic such as an epidural. The surgeon uses a fine fiber-optic cystoscope to examine the inside of the urethra and bladder, and then inserts a fine needle to inject the collagen. Usually three injections are made around the urethra. The exact amount of collagen used depends on how much closure the urethra requires.


Aftercare

Since the procedure is very short and there is little discomfort afterwards, it is performed on an outpatient basis, and women can go home the same day. Recovery from the operation is very quick.


Risks

Periurethral injection is not associated with major complications. Urinary tract infection is common in up to a fifth of the women having undergone the procedure, but is usually quickly and easily treated with antibiotics . Some women experience difficulty urinating immediately after the procedure, but this is not unexpected following an operation involving the bladder and urethra that may easily lead to swelling and bruising of the tissues. It is a relatively uncommon problem after periurethral injection, but may occur. The condition usually settles quickly, but may require catheterization. Long-term problems are very rare.


Normal results

Since periurethral injection is so quick and easy with very few complications, it would appear to be an ideal treatment for stress incontinence. However, there is a problem with the longer-term results. Within three months after injection, good results are reported with at least 80% of women cured or improved. However, after two years, less than half of these women will still be cured. Longer-term studies are still being performed, but it is likely that the results will keep becoming poorer as time goes by. This is due to the injected collagen dispersing away from the urethra over time. Injections can be repeated and some women do require more than one injection before they are cured. Ongoing research into newer injection substances may improve these results. The results in younger, physically active women are also less successful, usually lasting for a shorter time. Repeated injections are not the simple solution they may seem, because collagen is very expensive and the long-term effects of repeated injections are unknown. Physicians thus tend to prefer one of the alternative operations if long-term cure of stress incontinence is the aim.

Alternatives

Other treatments are available to treat incontinence. They include:

  • Physiotherapy. This treatment aims to increase the strength and support provided by the pelvic floor muscles.
  • Surgical procedures. Operations such as colposuspension, sling procedures, needle-suspensions, and vaginal repair operations are all based on lifting and re-supporting the bladder and urethra.

Resources

books

Burgio, K. L., L. Pearce, A. J. Lucco, and K. F. Jeter. Staying Dry: A Practical Guide to Bladder Control. Baltimore: Johns Hopkins University Press, 1990.

Kaschak Newman, D. Managing and Treating Urinary Incontinence. Baltimore: Health Professions Press, 2002.

periodicals

Block, C. A., C. S. Cooper, and C. E. Hawtrey. "Long-term Efficacy of Periurethral Collagen Injection for the Treatment of Urinary Incontinence Secondary to Myelomeningocele." Journal of Urology 169 (January 2003): 327329.

Culligan, P. J., et al. "The Safety of Reusing Injectable Collagen: A Multicenter Microbiological Study." International Urogynecological Journal of Pelvic Floor Dysfunction 13 (2002): 232234.

Dmochowski, R. R., and R. A. Appell. "Injectable Agents in the Treatment of Stress Urinary Incontinence in Women: Where Are We Now?" Urology 56 (December 2000): 3240.

Kassouf. W., G. Capolicchio, G. Berardinucci, and J. Corcos. "Collagen Injection for Treatment of Urinary Incontinence in Children." Journal of Urology 165 (May 2001): 16661668.

organizations

National Association for Women's Health. 300 W. Adams Street, Suite 328, Chicago, IL 60606-5101. (312) 786-1468. <http://www.nawh.org/>.

other

National Women's Health Information Center. <www.4woman,org/>.

"Periurethral Injection Therapy for Incontinence." eMedicine. <www.emedicine.com/med/topic3049.htm>.

"Stress Incontinence." MEDLINE Encyclopedia. <www.nlm.nih.gov/medlineplus/ency/article/000891.htm>.


Monique Laberge, Ph.D.

WHO PERFORMS THE PROCEDURE AND WHERE IS IT PERFORMED?


Collagen periurethral injection is a procedure that is performed in a hospital or clinic on an outpatient basis by a surgeon.

QUESTIONS TO ASK THE DOCTOR


  • How is a collagen periurethral injection performed?
  • Why is the collagen injection required?
  • What are the risks of the procedure?
  • Is the injection procedure painful?
  • Are there alternatives?
  • How long will it take to recover?
  • What are the after-effects of the injection?
  • How many collagen periurethral injection do you perform each year?

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Laberge, Monique. "Collagen Periurethral Injection." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Encyclopedia.com. 24 Jul. 2016 <http://www.encyclopedia.com>.

Laberge, Monique. "Collagen Periurethral Injection." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Encyclopedia.com. (July 24, 2016). http://www.encyclopedia.com/doc/1G2-3406200101.html

Laberge, Monique. "Collagen Periurethral Injection." Gale Encyclopedia of Surgery: A Guide for Patients and Caregivers. 2004. Retrieved July 24, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3406200101.html

collagen

collagen The word collagen means ‘glue-producing’. Collagen in the body does indeed help to hold it all together, but the notion of glue is not very apt. It strengthens and connects things with a network of tough fibres, rather than sticking them to each other — more like a cat's cradle than an adhesive. Collagen is the protein which forms the ubiquitous white fibres in all the connective tissues of the body, including bone, teeth, cartilage, and tendons; the skin; and all the sheaths, partitions, and supporting frameworks which abound in all organs and tissues. The exception is the central nervous system, which has its own different variety of internal supporting tissue — the glia — though there is collagen in the membranes which cover the brain and spinal cord.

Collagen is one of the ‘structural proteins’ (the other widespread one is elastin), which provide support to the tissues. By crude analogy with string, the principal mechanical property of collagen is its ability to resist distending force (tensile strength), which is vastly greater than its ability to resist compression or twisting (compression and torsion strengths). The tensile strength of collagen is so high as to be comparable, weight for weight, with that of steel. Elastin, by contrast, has a low tensile strength but the important mechanical properties of distensibility and resilience: the capability for relatively long range stretching under load and for returning to the original dimensions when the distending force is removed. Collagen can stretch only by about 2% without damage.

Collagen and elastin fibres often co-exist, notably in tissues which regularly undergo considerable changes in shape, such as skin, lungs, and blood vessels. The essentially inextensible, high tensile strength collagen is able to exist and function alongside the elastic fibres simply by having considerable slack. This can easily be illustrated if you pinch up the skin on the back of the hand: it returns to its original shape on release by virtue of the elastic fibres (a property progressively impaired in old age due to degeneration of the elastic fibres, with consequent increase in skin wrinkling). Now with the fingertips push the same skin on the back of the hand sideways and note that it slides quite freely until displacement comes to a distinct halt (when the collagen has used its slack and the tough fibres are pulled into alignment, resisting the distending force).

Collagen is synthesized by fibroblasts, the living cells present in all connective tissue, so named because they generate fibres — of collagen. There are in fact several types, with minor variations of molecular structure. Like all proteins, collagens are constructed from amino acid units; they are all glycoproteins, meaning that glucose and other simple sugars are attached to the amino acid chains. Each long, thin molecule consists of three chains of over 1000 units; each chain is helical, and the three in turn form a triple helix. A molecule is about 300 nm long — over 3000 end-to-end would measure 1 mm — but in fully-formed collagen they overlap lengthwise, and are also linked side to side, providing longer, wider, and very tough fibres. Again like all proteins in the body, collagen has a finite life span after which it is degraded to the constituent amino acids and replaced by new fibres. The synthesis within the fibroblasts is a complex process; the three chains are separately assembled, and then wound into the triple helix, which is extruded. Once outside the cell, the molecules aggregate and forge links as described.

The complexity of collagen synthesis involves multiple enzymes, so that a congenital deficiency of any of these can lead to some disorder of its formation. This accounts for there being a wide variety of clinical syndromes associated with such disorders: there can be fragile bones, with fractures from minimal trauma; fragile blood vessels with widespread bruising; dental defects; readily dislocating joints; a bent or twisted spine; thin, hyperelastic skin; and poor wound healing. Apart from these inborn defects, deprivation of ascorbic acid (vitamin C) at any time of life interferes with a step in collagen synthesis; the resulting bleeding, bruising, and poor healing are part of the picture of scurvy.

With ageing, habitually exposed areas of skin in white-skinned people show broken and disordered collagen fibres, related to the effects of UV light. Deficient replacement of collagen also contributes to thinning and wrinkling of the skin, and, together with mineral loss, to osteoporosis — decreasing bone mass.

These changes suggest that the continuous production of new fibroblasts, and by them of new collagen, progressively declines. Fibroblasts in culture outside the body divide again and again, but do not continue to replicate indefinitely. When such cultures from different animal species are compared, it is found that the number of cell divisions is related to the lifespan of each species, and is also related inversely to the age of the donor from any one species: a finding of considerable interest in the study of the ageing process.

Hugh Elder, and Sheila Jennett


See also ageing; connective tissue.

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COLIN BLAKEMORE and SHELIA JENNETT. "collagen." The Oxford Companion to the Body. 2001. Encyclopedia.com. 24 Jul. 2016 <http://www.encyclopedia.com>.

COLIN BLAKEMORE and SHELIA JENNETT. "collagen." The Oxford Companion to the Body. 2001. Encyclopedia.com. (July 24, 2016). http://www.encyclopedia.com/doc/1O128-collagen.html

COLIN BLAKEMORE and SHELIA JENNETT. "collagen." The Oxford Companion to the Body. 2001. Retrieved July 24, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O128-collagen.html

Collagen

Collagen


Collagen is a family of proteins; in animals these proteins play critical roles in tissue architecture, tissue strength, and cell to cell relationships. The major component of all connective tissue matrixes, collagen is found in tissues such as skin, blood vessels, bone, tendon, and ligament, and is characterized by tremendous strength.

The word "collagen" derives from the Greek word for "glue"; this derivation is based on the observation that insoluble collagen, when heated in water, becomes soluble, gummy gelatin that can be used in the manufacture of glues or as a thickener in foods. There are ten known forms of collagen that, because of differences in functional requirements and chemical environments, differ in some details of composition. All forms of collagen share the same basic structure: three polypeptide chains coiled together to form a triple helix . (These triple coils, in turn, become coiled together.) Collagen polypeptide chains generally contain around 1,000 amino acids.

An individual collagen polypeptide chain has a large number of repeating amino acid sequences, most often glycineXY, where X is often proline and Y is often hydroxyproline. Lysine, in its pure form or modified to hydroxylysine, is also found in collagen. Both hydroxyproline and hydroxylysine are formed via the enzyme-catalyzed oxidations of the proline and lysine amino acid side chains, which occur after the collagen polypeptide has been synthesized. These enzymatic reactions require ascorbic acid (vitamin C) as a cofactor .

Individual collagen polypeptides form an extended, left-handed triple helix, which is longer and less compact than the α -helixes often seen in proteins. Three of these helixes then form a molecule of tropocollagen , the basic building block of collagen, by coiling around a central axis in a right-handed, triple-helical arrangement. The side chain of every third amino acid is very close to the central axis of this superhelix . Glycine, with the smallest side chain of any amino acid, is more easily accommodated in these arrangements than the larger, bulkier amino acids.

Tropocollagen molecules associate in a staggered fashion to form collagen fibrils , which are stronger than steel wire of similar size. Collagen fibrils are strengthened and stabilized mainly by covalent cross-links, existing both within and between individual tropocollagen molecules. These crosslinks represent the enzyme-catalyzed formation of covalent bonds involving lysine and hydroxylysine side chains. The extent of cross-linking depends on the specific function of the collagen molecule involved and the age of the animal; older animals have more highly cross-linked and therefore more rigid collagen.

There are a number of collagen-related disorders that have been identified. Many of these are the result of derangements in the biosynthesis of collagen. Scurvy, characterized by bleeding gums, loose teeth, skin lesions, and weakened blood vessels, results from severe vitamin C deficiency, which makes it almost impossible for afflicted individuals to form hydroxyproline and hydroxylysine. The conditions, known collectively as the EhlersDanlo syndromes, result from defects in the processing of collagen polypeptides.

In addition to its importance in the production of animal glue, collagen is the basis for gelatin, which forms when collagen fibers are denatured as a result of heating and then get tangled up with each other. Collagen is also used for various biomedical applications.

see also Denaturation; Peptide Bond; Proteins.

Matthew A. Fisher

Bibliography

Branden, Carl, and Tooze, John (1999). Introduction to Protein Structure, 2nd edition. New York: Garland Publishing.

Meyers, Robert A., ed. (1995). Molecular Biology and Biotechnology: A Comprehensive Desk Reference. New York: VCH.

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Fisher, Matthew A.. "Collagen." Chemistry: Foundations and Applications. 2004. Encyclopedia.com. 24 Jul. 2016 <http://www.encyclopedia.com>.

Fisher, Matthew A.. "Collagen." Chemistry: Foundations and Applications. 2004. Encyclopedia.com. (July 24, 2016). http://www.encyclopedia.com/doc/1G2-3400900121.html

Fisher, Matthew A.. "Collagen." Chemistry: Foundations and Applications. 2004. Retrieved July 24, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1G2-3400900121.html

collagen

collagen (kŏl´əjən), any of a group of proteins found in skin, ligaments, tendons, bone and cartilage, and other connective tissue. Cells called fibroblasts form the various fibers in connective tissue in the body. The fibroblasts produce three types of fibers to form the ground substance: collagen, elatin, and the reticulum. Collagen consists of groups of white inelastic fibers with great tensile strength. These fibers include fine fibrils, which are composed of even finer filaments, visible only through the electron microscope. Collagen protein contains an unusually high percentage of the amino acids proline and hydroxyproline. X-ray diffraction studies provide evidence that the protein forms a wavy band, a coiled chain with periodic, i.e., repeating, arrangement of its amino acids. Cartilage is composed of fibrous collagen in an amorphous gel. The organic (nonmineral) content of bone is made up largely of collagen fibers with calcium salt crystals lying adjacent to each segment of the fiber; the fibers and salt crystals combined form a structure with compressional and tensile strength comparable to that of reinforced concrete. A group of diseases, often termed collagen, or connective tissue, diseases, involve a variety of alterations in the connective tissue fibers; rheumatoid arthritis, rheumatic fever, lupus, and scleroderma are included in this group. Some of these diseases may involve an autoimmune response, in which the immune mechanism injures or destroys the individual's own tissues (see immunity). Collagen dissolved in boiling water becomes denatured to form gelatin.

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"collagen." The Columbia Encyclopedia, 6th ed.. 2016. Encyclopedia.com. 24 Jul. 2016 <http://www.encyclopedia.com>.

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Collagen Vascular Diseases

Collagen Vascular Diseases

What are Collagen Vascular Diseases?

What Happens When People Have Collagen Vascular Diseases?

Living with Collagen Vascular Diseases

Resources

Collagen vascular diseases are a diverse group of diseases in which the body reacts against its own tissues, often causing joint pain and inflammation, fever, rash, fatigue, and difficulty swallowing.

KEYWORDS

for searching the Internet and other reference sources

Autoimmunity

Dermatomyositis

Inflammation

Lupus

Polyarteritis nodosa

Polymyositis

Rheumatology

Scleroderma

Sjögrens syndrome

Collagen vascular diseases have been recognized for a long time. Rheumatoid arthritis is a chronic inflammatory* disease that causes stiffness in the joints (places where bones meet), and can lead to disfigurement. It is an ancient disease; bone changes showing this condition have been identified in skeletons thousands of years old. Systemic lupus erythematosus (er-i-thee-ma-TO-sis), which affects multiple organs and tissues throughout the body, was first described in 1828.

* inflammation
is the bodys reaction to irritation, infection, or injury that often involves swelling, pain, redness, and warmth.

What are Collagen Vascular Diseases?

Collagen vascular diseases, sometimes called connective tissue diseases (CTDs) or autoimmune diseases, cover a wide array of disorders in which the bodys natural immune or self-protection system fails to recognize its own tissues and goes on attack against itself. Some of these diseases limit their damage to a single organ, and others spread problems throughout the body.

Immune responses to foreign bodies

In a healthy immune system, antigens (foreign bodies such as viruses and bacteria) are recognized as different from regular body tissues. When an antigen enters the bloodstream, it triggers the production of antibodies, substances that attack the alien substance. Lymphocytes (LIM-fo-sites) and leukocytes (LOO-ko-sites) are the special white blood cells responsible for creating these antibodies.

Lymphocytes include two subtypes (T cells and B cells), which have the unique ability to recognize the invading alien and alert the immune system to destroy it. The process is highly specialized: different lymphocytes recognize specific antigens and produce antibodies against only that particular antigen.

Autoimmune responses

In collagen vascular diseases, this immune system malfunctions. Rather than responding to foreign antigens, the body produces antibodies (autoantibodies) against its own antigens and normal proteins. Researchers do not understand what gets this autoimmune process started, but they have a fairly good idea of how it proceeds once it begins.

Systemic lupus erythematosus (SLE)

People with lupus develop antibodies to their own nucleic (noo-KLAY-ic) acids* and cell structures,

including those in the heart, kidneys, and joints. As a result of a faulty interaction between lymphocyte B and T cells, the cells fail to identify a protein as normal, mistake it for a foreign antigen, and then move on to produce autoantibodies called antinuclear antibodies. These antinuclear antibodies attack the nucleus and DNA (genetic material) in healthy cells. Immune complexes are the result of this mistaken battle. When they accumulate in the kidney, blood vessels, joints, and other sites, they cause inflammation and tissue damage.

* nucleic acids
are the cell structures that transfer genetic information: DNA (deoxyribonucleic acid) transfers information to RNA (ribonucleic acid), which leads to the production of body proteins.

Rheumatoid arthritis

In rheumatoid arthritis, the autoimmune process begins in connective tissue and the cushiony membranes that surround joints and the ends of bones. Collagen (KOL-a-jen) is the tough glue-like protein that gives joints their support and flexibility, and it represents 30 percent of the bodys protein. Rheumatoid arthritis is thought to begin when T cells mistake the bodys own collagen cells for foreign antigens and alert B cells to produce antibodies to fight the invader. The leukocytes rush in and produce cytokines (SY-to-kines), small proteins that are essential in healing the body but that cause serious damage in large doses. The inflammation and joint damage that result can lead to joint deformities and can spread throughout the body, wherever there is connective tissue.

Causes

Researchers are studying the causes of autoimmune diseases. Some autoimmune diseases have strong genetic components and may be passed down from parents to children. Environmental factors may act to trigger these diseases in some way. Fatigue, stress, and higher levels of certain antibodies also may lead to these diseases. Even ultraviolet rays of sunlight have been suggested as possible contributing causes. Collagen vascular diseases are not contagious; people cannot catch these diseases from one another.

What Happens When People Have Collagen Vascular Diseases?

Symptoms Symptoms differ depending on the illness, but they often include joint pain, fever, rash, recurrent infections, fatigue, mouth ulcers, dry mouth and dry eyes, hair loss, difficulty swallowing, swollen glands, or fingers and toes that get overly cold when exposed to cooler temperatures. In addition to systemic lupus erythematosus and rheumatoid arthritis, collagen vascular diseases include:

  • Scleroderma: This progressive and systemic sclerosis (skle-RO-sis) causes skin to thicken and tough fibrous tissue to form in the internal organs of the digestive tract, kidneys, heart, and lungs.
  • Sjögrens syndrome: This causes dry mouth, dry eyes, and other symptoms.
  • Polymyositis and dermatomyositis: These are inflammatory muscle disorders that may also affect the skin, the heart, and the lungs.
  • Mixed connective tissue diseases: These combine features of lupus, scleroderma, and polymyositis.
  • Polyarteritis nodosa: This disorder can damage small and medium-sized arteries of almost any organ, including the kidneys, heart, and intestines.

Diagnosis A complete medical history and a physical examination are the basis for the diagnosis of autoimmune disease. A number of laboratory tests can be used to help diagnose collagen vascular diseases. Blood tests can check levels of autoantibodies. Other tests include rheumatoid factor tests, urinalysis, blood counts, liver and kidney tests, and a sedimentation rate, which will give a nonspecific indicator of inflammation. A chest x-ray and other tests of specific lung function also may be done, since collagen vascular disorders occasionally produce breathing difficulties.

Treatment At present, there are no cures for autoimmune diseases, although some may go into remission as symptoms disappear for periods of time. Treatment depends on the extent of the disease. Doctors may prescribe steroid creams or anti-inflammatory medications to ease discomfort. In advanced cases, immunosuppressant drugs may help lessen the immune systems over-reaction.

Living with Collagen Vascular Diseases

These serious diseases often require adjustments in activities of daily living. People with rheumatoid arthritis often have early morning stiffness that lasts for about an hour, after which they can go on about their day. Avoiding certain foods, and reducing physical and emotional stresses, also seem to reduce symptoms for some people.

See also

Arthritis

Fever

Hair Loss

Infection

Lupus

Resources

American Autoimmune Related Diseases Association, 15475 Gratiot Avenue, Detroit, MI 48205

Telephone 313-371-8600
http://www.aarda.org

Lupus Foundation of America, 1300 Piccard Drive, Suite 200,
Rockville, MD 20850-4303
Telephone 301-670-9292
http://www.lupus.org

Sjögrens Syndrome Foundation, 333 North Broadway,
Jericho, NY 11753
Telephone 800-4-SJOGRENS
http://sjogrens.com

Scleroderma Foundation, 89 Newbury Street, Suite 201,
Danvers, MA 01923
Telephone 800-722-HOPE
http://www.scleroderma.org

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collagen

collagen A fibrous scleroprotein that is almost inert, of high tensile strength, and relatively inelastic, which is a major constituent of connective tissue and the organic material in bone. It may represent up to 6% of the total body weight. It is unusual among proteins in that glycine, proline, and hydroxyproline represent over 50% of the total amino-acid residues; and these are arranged in a tight, triple left-handed helix. When boiled, collagen yields gelatin.

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MICHAEL ALLABY. "collagen." A Dictionary of Zoology. 1999. Encyclopedia.com. 24 Jul. 2016 <http://www.encyclopedia.com>.

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collagen

collagen An insoluble fibrous protein found extensively in the connective tissue of skin, tendons, and bone. The polypeptide chains of collagen (containing the amino acids glycine and proline predominantly) form triple-stranded helical coils that are bound together to form fibrils, which have great strength and limited elasticity. Collagen accounts for over 30% of the total body protein of mammals.

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"collagen." A Dictionary of Biology. 2004. Encyclopedia.com. 24 Jul. 2016 <http://www.encyclopedia.com>.

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collagen

collagen Fibrous scleroprotein of high tensile strength which is a major constituent of connective tissue and the organic material in bone. It may represent up to 6% of the total body weight. When boiled, collagen yields gelatin.

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collagen

collagen (kol-ă-jin) n. a protein that is the principal constituent of white fibrous connective tissue (as occurs in tendons). Collagen is also found in skin, bone, cartilage, and ligaments.

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collagen

col·la·gen / ˈkäləjən/ • n. Biochem. the main structural protein found in animal connective tissue, yielding gelatin when boiled.

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collagen

collagen Protein substance that is the main constituent of bones, tendons, cartilage, connective tissue and skin. It is made up of inelastic fibres that form a mesh.

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collagen

collagen Insoluble protein in connective tissue, bones, tendons, and skin of animals and fish; converted into the soluble protein, gelatine, by moist heat.

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DAVID A. BENDER. "collagen." A Dictionary of Food and Nutrition. 2005. Encyclopedia.com. (July 24, 2016). http://www.encyclopedia.com/doc/1O39-collagen.html

DAVID A. BENDER. "collagen." A Dictionary of Food and Nutrition. 2005. Retrieved July 24, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O39-collagen.html

collagen

collagenabrasion, Australasian, equation, Eurasian, evasion, invasion, occasion, persuasion, pervasion, suasion, Vespasianadhesion, cohesion, Friesian, lesion •circumcision, collision, concision, decision, derision, division, elision, envision, excision, imprecision, incision, misprision, precisian, precision, provision, scission, vision •subdivision • television • Eurovision •LaserVision •corrosion, eclosion, erosion, explosion, implosion •allusion, collusion, conclusion, confusion, contusion, delusion, diffusion, effusion, exclusion, extrusion, fusion, illusion, inclusion, interfusion, intrusion, obtrusion, occlusion, preclusion, profusion, prolusion, protrusion, reclusion, seclusion, suffusion, transfusion •Monaghan • Belgian •Bajan, Cajun, contagion, TrajanGlaswegian, legion, Norwegian, region •irreligion, religion •Injun • Harijan • oxygen • antigen •sojourn • donjon • Georgian •theologian, Trojan •Rügen •bludgeon, curmudgeon, dudgeon, gudgeon, trudgen •dungeon • glycogen • halogen •collagen • Imogen • carcinogen •hallucinogen • androgen •oestrogen (US estrogen) •hydrogen • nitrogen •burgeon, sturgeon, surgeon

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"collagen." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. 24 Jul. 2016 <http://www.encyclopedia.com>.

"collagen." Oxford Dictionary of Rhymes. 2007. Encyclopedia.com. (July 24, 2016). http://www.encyclopedia.com/doc/1O233-collagen.html

"collagen." Oxford Dictionary of Rhymes. 2007. Retrieved July 24, 2016 from Encyclopedia.com: http://www.encyclopedia.com/doc/1O233-collagen.html

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