Тератология (наука): различия между версиями
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== Общие сведения ==
Наука тесно связанная со сравнительной и патологической анатомией, эмбриологией и генетикой. Исследования тератологии имеют большое значение для познания правильного развития организмов, по той причине что у уродов особенно видны специфические свойства развития.
Предметом тератологических исследований есть описание недостатков и уродств, а так же обнаружение причин (тератологические факторы) их появления. У человека важным тератологическим фактором могут быть наркотики, лекарства и другие химические субстанции. Другие причины аномалии
* Ионизирующее излучения.▼
<br />
== История ==
В одном из четверостиший [[Эмпедокл]]а содержится указание на рождение сросшихся близнецов, обезображивающие пороки лица и двуполость.
Ранняя политическая теория Китая зачастую проявляет интерес к природным аномалиям, как отражающим сбой космического баланса, причинённый неумелым управлением. Яркий пример такого рода содержится в «[[Анналы Люй Бувэя|Анналах Люй Бувэя]]», III
=== В России ===
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* [[Талидомид]]
* [[Фетальный алкогольный синдром]]
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== Литература ==
'''Teratology''' (from the [[Greek language|Greek]] {{Polytonic|τέρᾰς}} ([[genitive]] {{Polytonic|τέρᾰτος}}), meaning ''monster'', or ''marvel'' and {{Polytonic|''λόγος''}}, meaning ''word'', ''speech'') as early as 17th century referred to a discourse on prodigies and marvels, of anything so extraordinary as to seem abnormal. In 19th century, it acquired a meaning closer related to biological deformities, mostly in the field of botany. Currently, its most instrumental meaning is that of the medical study of teratogenesis, [[Congenital disorder|congenital malformations]] or grossly deformed individuals. ''Monster'' is a [[pejorative]] term for a grossly deformed individual, although it is interesting to note that, etymologically, this word is related to ''demonstration'', and used to simply mean something worth looking at, for being unusual, without necessarily being pejorative. Another term for this is '''dysmorphology''', which literally means «the study of abnormal form.»
Teratology as a medical term was popularized in the 1960s by Dr. David W. Smith of the [[University of Washington]] Medical School, one of the researchers who became known in 1973 for the discovery of [[Fetal alcohol syndrome]].{{Fact|date=June 2007}} With greater understanding of the origins of birth defects, the field of teratology now overlaps with other fields of medicine, including [[developmental biology]], [[embryology]], and [[genetics]].
== Teratogenesis and teratology ==
Birth defects are known to occur in 3-5 % of all newborns.<ref>{{cite web |url=http://www.marchofdimes.com/pnhec/4439_1206.asp |title=Birth Defects & Genetics: Birth Defects |accessdate=2007-05-30 |format= |work=}}</ref> They are the leading cause of infant mortality in the United States, accounting for more than 20 % of all infant deaths. Seven to ten percent of all children will require extensive medical care to diagnose or treat a birth defect.<ref name="pmid2468064">{{cite journal |author=Dicke JM |title=Teratology: principles and practice |journal=Med. Clin. North Am. |volume=73 |issue=3 |pages=567-82 |year=1989 |pmid=2468064 |doi=}}</ref> Although significant progress has been made in identifying etiologic causes of some birth defects, approximately 65 % have no known or identifiable cause.<ref name="isbn0-471-38225-6">{{cite book |author=Ronan O'Rahilly, Fabiola Müller |title=Human embryology & teratology |publisher=Wiley-Liss |location=New York |year=2001 |pages= |isbn=0-471-38225-6 |oclc= |doi=}}</ref>
It was previously believed that the [[mammalian]] [[embryo]] developed in the impervious uterus of the mother, protected from all extrinsic factors. However, after the [[thalidomide]] disaster of the 1960’s, it became apparent and more accepted that the developing [[embryo]] could be highly vulnerable to certain environmental agents that have negligible or non-toxic effects to adult individuals.
=== Wilson’s 6 principles ===
Along with this new awareness of the [[in utero]] vulnerability of the developing [[mammalian]] [[embryo]] came the development and refinement of ''The Six Principles of Teratology'' which are still applied today. These principles of teratology were put forth by Jim Wilson in 1959 and in his monograph Environment and Birth Defects.<ref name="isbn0-12-757750-5">{{cite book |author=James G. Wilson, |title=Environment and Birth Defects (Environmental Science Series) |publisher=Academic Pr |location=London |year= |pages= |isbn=0-12-757750-5 |oclc= |doi=}}</ref> It is these principles that guide the study and understanding of teratogenic agents and their effects on developing organisms
* Susceptibility to teratogenesis depends on the genotype of the conceptus and the manner in which this interacts with adverse environmental factors.
* Susceptibility to teratogenesis varies with the developmental stage at the time of exposure to an adverse influence. There are critical periods of susceptibility to agents and organ systems affected by these agents.
* Teratogenic agents act in specific ways on developing cells and tissues to initiate sequences of abnormal developmental events.
* The access of adverse influences to developing tissues depends on the nature of the influence. Several factors affect the ability of a teratogen to contact a developing conceptus, such as the nature of the agent itself, route and degree of maternal exposure, rate of placental transfer and systemic absorption, and composition of the maternal and embryonic/fetal genotypes.
* There are four manifestations of deviant development (Death, Malformation, Growth Retardation and Functional Defect).
* Manifestations of deviant development increase in frequency and degree as dosage increases from the No Observable Adverse Effect Level (NOAEL) to a dose producing 100 % Lethality (LD100).
Studies designed to test the teratogenic potential of environmental agents use animal model systems (e.g., rat, mouse, rabbit, dog, and monkey). Early teratologists exposed pregnant animals to environmental agents and observed the fetuses for gross visceral and skeletal abnormalities. While this is still part of the teratological evaluation procedures today, the field of Teratology is moving to a more [[molecular]] level, seeking the mechanism(s) of action by which these agents act. In addition, pregnancy registries are large, prospective studies that monitor exposures women receive during their pregnancies and record the outcome of their births. These studies provide information about possible risks of medications or other exposures in human pregnancies.
Understanding how a [[teratogen]] causes its effect is not only important in preventing congenital abnormalities but also has the potential for developing new therapeutic drugs safe for use with pregnant women.
== Teratology education ==
It is estimated that 10 % of all birth defects are caused by a prenatal exposure or teratogen.<ref name="isbn0-471-38225-6" /> These exposures include, but are not limited to, medication or drug exposures, maternal infections and diseases, and environmental and occupational exposures. Teratogen-caused birth defects are potentially preventable. Studies have shown that nearly 50 % of pregnant women have been exposed to at least one medication during gestation.<ref name="pmid7266953">{{cite journal |author=Bracken MB, Holford TR |title=Exposure to prescribed drugs in pregnancy and association with congenital malformations |journal=Obstetrics and gynecology |volume=58 |issue=3 |pages=336-44 |year=1981 |pmid=7266953 |doi=}}</ref> An additional study found that of 200 individuals referred for genetic counseling for a teratogenic exposure, 52 % were exposed to more than one potential teratogen.<ref name="pmid3703408">{{cite journal |author=King CR |title=Genetic counseling for teratogen exposure |journal=Obstetrics and gynecology |volume=67 |issue=6 |pages=843-6 |year=1986 |pmid=3703408 |doi=}}</ref>
Despite scientific advances in clinical teratology, exposures prior to and during pregnancy still cause great anxiety and misunderstanding among both the public and health care professionals. Teratology Information Services (TIS) are comprehensive and multi-disciplinary resources for medical consultation on prenatal exposures. Pregnant women, health care providers, and the general public may call the toll-free number of their local TIS to receive up-to-date, evidence-based information about exposures during pregnancy.
== Teratogenic agents ==
A wide range of different chemicals and environmental factors are suspected or are known to be teratogenic in humans and in animals. A selected few include:
* Ionizing radiation: [[atomic weapons]], [[radioiodine]], [[radiation therapy]]
* Infections: [[cytomegalovirus]], [[herpes virus]], [[parvovirus|parvovirus B-19]], [[rubella|rubella virus (German measles)]], [[syphilis]], [[toxoplasmosis]], [[Venezuelan equine encephalitis virus]]
* Metabolic imbalance: [[alcoholism]], [[cretinism|endemic cretinism]], [[diabetes]], [[folic acid deficiency]], [[hyperthermia]], [[phenylketonuria]], [[rheumatic disease]] and [[heart block|congenital heart block]], [[Virilization|virilizing tumors]]
* Drugs and environmental chemicals: [[retinoic acid|13-cis-retinoic acid]], [[isotretinoin|isotretinoin (Accutane)]], [[aminopterin]], [[androgenic|androgenic hormones]], [[busulfan]], [[captopril]], [[enalapril]], [[Polychlorinated biphenyl|chlorobiphenyls (PCBs)]], [[Dioxin]], [[coumarin]], [[cyclophosphamide]], [[diethylstilbestrol]], [[phenytoin|diphenylhydantoin (Phenytoin, Dilantin, Epanutin)]], [[ethanol]], [[ethidium bromide]], [[etretinate]], [[lithium]], [[methimazole]], [[mercury (element)|organic mercury]], [[penicillamine]], [[tetracyclines]], [[thalidomide]], [[trimethadione]], [[uranium]], [[methoxyethyl ethers]] and [[valproic acid]].
The status of some of the above substances (e.g. diphenylhydantoin) is subject to debate, and many other compounds are under varying degrees of suspicion. These include [[Agent Orange]],<ref name="pmid6137083">{{cite journal |author=Linnainmaa K |title=Sister chromatid exchanges among workers occupationally exposed to phenoxy acid herbicides 2,4-D and MCPA |journal=Teratog., Carcinog. Mutagen. |volume=3 |issue=3 |pages=269-79 |year=1983 |pmid=6137083 |doi=}}</ref> [[nicotine]],<ref name="pmid15033289">{{cite journal |author=Vaglenova J, Birru S, Pandiella NM, Breese CR |title=An assessment of the long-term developmental and behavioral teratogenicity of prenatal nicotine exposure |journal=Behav. Brain Res. |volume=150 |issue=1-2 |pages=159-70 |year=2004 |pmid=15033289 |doi=10.1016/j.bbr.2003.07.005}}</ref> [[aspirin]] and other [[NSAID]]s. Other compounds are known as severe teratogens based on veterinary work and animal studies, but aren’t listed above because they have not been studied in humans, e.g. [[cyclopamine]]. Teratogenic effects also help to determine the [[pregnancy category]] assigned by regulatory authorities; in the United States, a pregnancy category of X, D, or C may be assigned if teratogenic effects (or other risks in pregnancy) are documented or cannot be excluded.
[[Isotretinoin]] (13-cis-retinoic-acid; brand name Accutane), which is often used to treat severe [[Acne vulgaris|acne]], is such a strong teratogen that just a single dose taken by a pregnant woman may result in serious [[birth defect]]s. Because of this effect, most countries have systems in place to ensure that it is not given to pregnant women, and that the patient is aware of how important it is to prevent pregnancy during and at least one month after treatment. Medical guidelines also suggest that pregnant women should limit [[vitamin A]] intake to about 700 [[μg]]/day, as it has teratogenic potential when consumed in excess.<ref name="pmid8602195">{{cite journal |author=Hunt JR |title=Teratogenicity of high vitamin A intake |journal=N. Engl. J. Med. |volume=334 |issue=18 |pages=1197 |year=1996 |pmid=8602195 |doi=}}</ref><ref name="pmid16028634">{{cite journal |author=Hartmann S, Brørs O, Bock J, ''et al'' |title=Exposure to retinoic acids in non-pregnant women following high vitamin A intake with a liver meal |journal=International journal for vitamin and nutrition research. Internationale Zeitschrift für Vitamin- und Ernährungsforschung. Journal international de vitaminologie et de nutrition |volume=75 |issue=3 |pages=187-94 |year=2005 |pmid=16028634 |doi=}}</ref>
== Teratogenic outcomes ==
Exposure to teratogens can result in a wide range of structural abnormalities such as [[cleft lip]], [[cleft palate]], [[dysmelia]], [[anencephaly]], [[ventricular septal defect]]. In most cases, specific agents produce a specific teratogenic response.
== References ==
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== Ссылки ==
* {{Из БСЭ|заглавие=Тератология}}
* {{ВТ-ЭСБЕ+|Тератология}}
=== На английском языке ===
* [http://www.teratology.org/ Society of Teratology]
* [http://www.etsoc.com/ European Teratology Society]
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