n.

萎縮

WordNet

a decrease in size of an organ caused by disease or disuse (同)wasting, wasting away
undergo atrophy; "Muscles that are not used will atrophy"
any weakening or degeneration (especially through lack of use) (同)withering
check the growth of; "the lack of sunlight dwarfed these pines"
a plant or animal that is atypically small
a person who is markedly small (同)midget, nanus
reduction in size of an organ or part (as in the return of the uterus to normal size after childbirth)
the action of enfolding something (同)enfolding
a long and intricate and complicated grammatical construction
decrease in phase; "the moon is waning"
become smaller; "Interest in his novels waned"
relating to or characterized by atrophy; "atrophic arthritis"

PrepTutorEJDIC

(栄養不良などによる)萎縮(いしゅく) / (一般的に)衰退,退化 / 萎縮する,衰退する / …'を'萎縮させる,衰退させる
(童話の)『こびと』,一寸法師 / (人間の)こびと / 普通よりずっと小さい動物(植物) / (対照的に)…‘を'小さく見せる / 〈植物など〉‘の'自然な成長を妨げる / (並みはずれて)小さい[種類の]
巻き(包み)込むこと,巻き込まれた状態 / 複雑なもの,込み入ったもの
〈月が〉『欠ける』;〈潮が〉引く《+away》 / 〈光・勢力などが〉衰える,弱まる / 〈季節などが〉終りに近づく / 月が欠けること / 衰え,衰弱

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/04/16 21:50:37」(JST)

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[Wiki en表示]

For the American thrash metal band, see Atrophy (band).

Atrophy (from Ancient Greek ἀτροφία atrophia, "a wasting away", from ἀ- a-, "not" and τροφή trophē, "food") is the partial or complete wasting away of a part of the body. Causes of atrophy include mutations (which can destroy the gene to build up the organ), poor nourishment, poor circulation, loss of hormonal support, loss of nerve supply to the target organ, excessive amount of apoptosis of cells, and disuse or lack of exercise or disease intrinsic to the tissue itself. Hormonal and nerve inputs that maintain an organ or body part are referred to as trophic [noun] in medical practice ('trophic" is an adjective that can be paired with various nouns). Trophic describes the trophic condition of tissue. A diminished muscular trophic is designated as atrophy.

Atrophy is the general physiological process of reabsorption and breakdown of tissues, involving apoptosis. When it occurs as a result of disease or loss of trophic support due to other disease, it is termed pathological atrophy, although it can be a part of normal body development and homeostasis as well.

Atrophy examples

Normal development

Examples of atrophy as part of normal development include shrinking and the involution of the thymus in early childhood, and the tonsils in adolescence. In old age, effects include, but are not limited to, loss of teeth, hair, thinning of skin that creates wrinkles, weakening of muscles, loss of weight in organs and sluggish mental activity.^[1]

Muscle atrophies

Main article: Muscle atrophy

Disuse atrophy of muscles and bones, with loss of mass and strength, can occur after prolonged immobility, such as extended bedrest, or having a body part in a cast (living in darkness for the eye, bedridden for the legs etc.). This type of atrophy can usually be reversed with exercise unless severe. Astronauts in microgravity must exercise regularly to minimize atrophy of their limb muscles.

There are many diseases and conditions which cause atrophy of muscle mass. For example diseases such as cancer and AIDS induce a body wasting syndrome called "cachexia", which is notable for the severe muscle atrophy seen. Other syndromes or conditions which can induce skeletal muscle atrophy are congestive heart failure and liver disease.

During aging, there is a gradual decrease in the ability to maintain skeletal muscle function and mass. This condition is called "sarcopenia", and may be distinct from atrophy in its pathophysiology. While the exact cause of sarcopenia is unknown, it may be induced by a combination of a gradual failure in the "satellite cells" which help to regenerate skeletal muscle fibers, and a decrease in sensitivity to or the availability of critical secreted growth factors which are necessary to maintain muscle mass and satellite cell survival.^[2]

Dystrophies, myositis, and motor neuron conditions

Pathologic atrophy of muscles can occur with diseases of the motor nerves, or diseases of the muscle tissue itself. Examples of atrophying nerve diseases include CMT (Charcot Marie Tooth syndrome) poliomyelitis, amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), and Guillain-Barré syndrome. Examples of atrophying muscle diseases include muscular dystrophy, myotonia congenita, and myotonic dystrophy.

Changes in Na+ channel isoform expression and spontaneous activity in muscle called fibrillation can also result in muscle atrophy.

Gland atrophy

The adrenal glands atrophy during prolonged use of exogenous glucocorticoids like prednisone. Atrophy of the breasts can occur with prolonged estrogen reduction, as with anorexia nervosa or menopause. Testicular atrophy with prolonged use of enough exogenous sex steroid (either androgen or estrogen) to reduce gonadotropin secretion.

Vaginal atrophy

In post-menopausal women, the walls of the vagina become thinner (atrophic vaginitis). The mechanism for the age-related condition is not yet clear, though there are theories that the effect is caused by decreases in estrogen levels.^[3] This atrophy, and that of the breasts concurrently, is consistent with the homeostatic (normal development) role of atrophy in general, as after menopause the body has no further functional biological need to maintain the reproductive system which it has permanently shut down.

Research

It has been reported that some drugs might prevent the loss of the muscle wasting that occurs in immobile, bedridden patients.^[4] Testing upon mice showed that it blocked the activity of a protein present in the muscle that is involved in muscle atrophy.^[5] However the concerns for the drug's long-term effects on the heart preclude its routine use in humans for this indication, and further alternative drugs are being sought.^[4]

References

^ W. T. Councilman (1913). "Chapter Two". Disease and Its Causes. New York Henry Holt and Company London Williams and Norgate The University Press, Cambridge, U.S.A.
^ Campellone, Joseph V. (2007-05-22). "Muscle atrophy". MedlinePlus. Archived from the original on 13 October 2007. Retrieved 2007-10-02.
^ "Types of Atrophy". Archived from the original on 28 September 2007. Retrieved 2007-10-02.
^ ^a ^b "Drug could stop muscle wasting'". NetDoctor.co.uk. 2006-05-25. Retrieved 2006-05-27. ^{[dead link]}
^ Wang X, Hockerman GH, Green Iii HW, Babbs CF, Mohammad SI, Gerrard D, Latour MA, London B, Hannon KM, Pond AL (May 24, 2006). "Merg1a K+ channel induces skeletal muscle atrophy by activating the ubiquitin proteasome pathway". FASEB J 20 (9): 1531. doi:10.1096/fj.05-5350fje. PMID 16723379.

UpToDate Contents

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1. 脊髄性筋萎縮症 spinal muscular atrophy
2. 膣萎縮症の治療 treatment of vaginal atrophy
3. 筋力低下の評価における筋力検査 muscle examination in the evaluation of weakness
4. Rapid eye movement sleep behavior disorder
5. 遺伝性痙性対麻痺 hereditary spastic paraplegia

English Journal

Pathophysiology in the comorbidity of Bipolar Disorder and Alzheimer's Disease: pharmacological and stem cell approaches.

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Emerging roles of ER stress and unfolded protein response pathways in skeletal muscle health and disease.

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Identification of Genetic Disorders Causing Disruption of Selenoprotein Biosynthesis.

Schoenmakers E1, Chatterjee K2.
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Voxel-based mapping of grey matter volume and glucose metabolism profiles in amyotrophic lateral sclerosis.

Buhour MS1, Doidy F1, Mondou A1, Pélerin A1, Carluer L1, Eustache F1, Viader F1, Desgranges B2.
EJNMMI research.EJNMMI Res.2017 Dec;7(1):21. doi: 10.1186/s13550-017-0267-2. Epub 2017 Mar 6.
PMID 28266002

Japanese Journal

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NAID 130005110891

対策型胃X線検診での萎縮度評価とABC分類の年齢階級別対比 : 高齢者ではA群でも萎縮進行例が多い

日本消化器がん検診学会雑誌 = Journal of gastroenterological cancer screening 53(6), 766-774, 2015-11
NAID 40020658641

Joint effect of the SMN2 and SERF1A genes on childhood-onset types of spinal muscular atrophy in Serbian patients

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症例報告音楽嗜好症(musicophilia)を呈した右側優位側頭葉萎縮の1例

Brain and nerve : 神経研究の進歩 67(11), 1443-1448, 2015-11
NAID 40020653156

Related Pictures

★リンクテーブル★

リンク元	「involution」「dwarf」「萎縮」「萎縮症」「atrophic」
拡張検索	「progressive muscular atrophy」「congenital microvillus atrophy」