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Cyclopia
Cyclopia (named after the Greek mythology character cyclopes) is the most extreme form of holoprosencephaly and is a congenital disorder (birth defect) characterized by the failure of the embryonic prosencephalon to properly divide the orbits of the eye into two cavities. Its incidence is 1 in 16,000 in born animals and 1 in 200 in miscarried fetuses. Signs and symptoms Typically, the nose is either missing or not functional. This deformity (called proboscis) forms above the center eye and is characteristic of a form of cyclopia called rhinencephaly or rhinocephaly. Most such embryos are either naturally aborted or are stillborn upon delivery. Although cyclopia is rare, several cyclopic human babies are preserved in medical museums (e.g. The Vrolik Museum, Amsterdam, Trivandrum Medical College). Some extreme cases of cyclopia have been documented in farm animals (horses, sheep, pigs, and sometimes chickens). In such cases, the nose and mouth fail to form, or the nose grows ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopamine
Cyclopamine (11-deoxojervine) is a naturally occurring chemical that belongs in the family of steroidal alkaloids. It is a teratogen isolated from the corn lily ('' Veratrum californicum'') that causes fatal birth defects. It prevents the embryonic brain from separating into two lobes (an extreme form of holoprosencephaly), which in turn causes the development of a single eye ( cyclopia). The chemical was named after this effect, as it was originally noted by Idaho lamb farmers who contacted the US Department of Agriculture after their herds gave birth to cycloptic lambs in 1957. It then took more than a decade to identify the corn lily as the culprit. Later work suggested that different rain patterns caused the sheep to graze differently, impacting the amount of corn lily ingested by pregnant sheep. The poison interrupts the sonic hedgehog signaling pathway during development, thus causing birth defects. Discovery and naming In 1957, Idaho sheep ranchers contacted the US Depar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Proboscis (anomaly)
In teratology, a proboscis is a blind-ended, tube-like structure, commonly located in the middle of the face. It is commonly seen in severe forms of holoprosencephaly that include cyclopia and is usually the result of abnormal development of the nose. Types Proboscis formation is classified in four general types: holoprosencephalic proboscis, lateral nasal proboscis, supernumerary probosci, and disruptive proboscis. Holoprosencephalic proboscis A holoprosencephalic proboscis is found in holoprosencephaly (a condition in which the forebrain of the embryo fails to develop into two hemispheres as it should). In cyclopia or ethmocephaly, proboscis is an abnormally formed nose. In cyclopia, a single eye in the middle of the face is associated with arrhinia (absence of the nose) and usually with proboscis formation above the eye. In ethmocephaly Ethmocephaly is a type of cephalic disorder caused by holoprosencephaly. Ethmocephaly is the rarest phenotypic variant of a group of def ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holoprosencephaly
Holoprosencephaly (HPE) is a cephalic disorder in which the prosencephalon (the forebrain of the embryo) fails to develop into two hemispheres, typically occurring between the 18th and 28th day of gestation. Normally, the forebrain is formed and the face begins to develop in the fifth and sixth weeks of human pregnancy. The condition also occurs in other species. Holoprosencephaly is estimated to occur in approximately 1 in every 250 conceptions and most cases are not compatible with life and result in fetal death in utero due to deformities to the skull and brain. However, holoprosencephaly is still estimated to occur in approximately 1 in every 8,000 live births. When the embryo's forebrain does not divide to form bilateral cerebral hemispheres (the left and right halves of the brain), it causes defects in the development of the face and in brain structure and function. The severity of holoprosencephaly is highly variable. In less severe cases, babies are born with normal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holoprosencephaly
Holoprosencephaly (HPE) is a cephalic disorder in which the prosencephalon (the forebrain of the embryo) fails to develop into two hemispheres, typically occurring between the 18th and 28th day of gestation. Normally, the forebrain is formed and the face begins to develop in the fifth and sixth weeks of human pregnancy. The condition also occurs in other species. Holoprosencephaly is estimated to occur in approximately 1 in every 250 conceptions and most cases are not compatible with life and result in fetal death in utero due to deformities to the skull and brain. However, holoprosencephaly is still estimated to occur in approximately 1 in every 8,000 live births. When the embryo's forebrain does not divide to form bilateral cerebral hemispheres (the left and right halves of the brain), it causes defects in the development of the face and in brain structure and function. The severity of holoprosencephaly is highly variable. In less severe cases, babies are born with normal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cyclopes
In Greek mythology and later Roman mythology, the Cyclopes ( ; el, Κύκλωπες, ''Kýklōpes'', "Circle-eyes" or "Round-eyes"; singular Cyclops ; , ''Kýklōps'') are giant one-eyed creatures. Three groups of Cyclopes can be distinguished. In Hesiod's ''Theogony'', the Cyclopes are the three brothers Brontes, Steropes, and Arges, who made for Zeus his weapon the thunderbolt. In Homer's ''Odyssey'', they are an uncivilized group of shepherds, the brethren of Polyphemus encountered by Odysseus. Cyclopes were also famous as the builders of the Cyclopean walls of Mycenae and Tiryns. In ''Cyclops'', the fifth-century BC play by Euripides, a chorus of satyrs offers comic relief based on the encounter of Odysseus and Polyphemus. The third-century BC poet Callimachus makes the Hesiodic Cyclopes the assistants of smith-god Hephaestus; as does Virgil in the Latin epic ''Aeneid'', where he seems to equate the Hesiodic and Homeric Cyclopes. From at least the fifth century BC, Cy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hellebore
Commonly known as hellebores (), the Eurasian genus ''Helleborus'' consists of approximately 20 species of herbaceous or evergreen perennial flowering plants in the family Ranunculaceae, within which it gave its name to the tribe of Helleboreae. Despite names such as "winter rose", "Christmas rose" and "Lenten rose", hellebores are not closely related to the rose family (Rosaceae). Many hellebore species are poisonous. Description The flowers have five petal-like sepals surrounding a ring of small, cup-like nectaries which are actually petals modified to hold nectar. The sepals do not fall as petals would, but remain on the plant, sometimes for many months. Recent research in Spain suggests that the persistence of the sepals contributes to the development of the seeds. Taxonomy The genus was established by Carl Linnaeus in volume one of his ''Species Plantarum'' in 1753. The scientific name ''Helleborus'' could derive from the Ancient Greek word (), the common name for '' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Veratrum Californicum
''Veratrum californicum'' (California corn lily, white or California false hellebore) is an extremely poisonous plant native to western North America, including the Sierra Nevada and Rocky Mountains, as far north as Washington and as far south as Durango; depending on latitude, it grows from near sea level to as high as 11,000 feet. It grows 1 to 2 meters tall, with an erect, unbranched, heavily leafy stem resembling a cornstalk. It prefers quite moist soil, and can cover large areas in dense stands near streams or in wet meadows. Many inch-wide flowers cluster along the often-branched top of the stout stem; they have 6 white tepals, a green center, 6 stamens, and a 3-branched pistil (see image below). The buds are tight green spheres. The heavily veined, bright green leaves can be more than a foot long. ''Veratrum californicum'' displays mast seeding; populations bloom and seed little in most years, but in occasional years bloom and seed heavily in synchrony. The species us ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
United Kingdom
The United Kingdom of Great Britain and Northern Ireland, commonly known as the United Kingdom (UK) or Britain, is a country in Europe, off the north-western coast of the European mainland, continental mainland. It comprises England, Scotland, Wales and Northern Ireland. The United Kingdom includes the island of Great Britain, the north-eastern part of the island of Ireland, and many List of islands of the United Kingdom, smaller islands within the British Isles. Northern Ireland shares Republic of Ireland–United Kingdom border, a land border with the Republic of Ireland; otherwise, the United Kingdom is surrounded by the Atlantic Ocean, the North Sea, the English Channel, the Celtic Sea and the Irish Sea. The total area of the United Kingdom is , with an estimated 2020 population of more than 67 million people. The United Kingdom has evolved from a series of annexations, unions and separations of constituent countries over several hundred years. The Treaty of Union between ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sonic Hedgehog (protein)
Sonic hedgehog protein (SHH) is encoded for by the ''SHH'' gene. The protein is named after the character ''Sonic the Hedgehog''. This signaling molecule is key in regulating embryonic morphogenesis in all animals. SHH controls organogenesis and the organization of the central nervous system, limbs, digits and many other parts of the body. Sonic hedgehog is a morphogen that patterns the developing embryo using a concentration gradient characterized by the French flag model. This model has a non-uniform distribution of SHH molecules which governs different cell fates according to concentration. Mutations in this gene can cause holoprosencephaly, a failure of splitting in the cerebral hemispheres, as demonstrated in an experiment using SHH knock-out mice in which the forebrain midline failed to develop and instead only a single fused telencephalic vesicle resulted. Sonic hedgehog still plays a role in differentiation, proliferation, and maintenance of adult tissues. Abnormal act ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pax6
Paired box protein Pax-6, also known as aniridia type II protein (AN2) or oculorhombin, is a protein that in humans is encoded by the ''PAX6'' gene. Function PAX6 is a member of the Pax gene family which is responsible for carrying the genetic information that will encode the Pax-6 protein. It acts as a "master control" gene for the development of eyes and other sensory organs, certain neural and epidermal tissues as well as other homologous structures, usually derived from ectodermal tissues. However, it has been recognized that a suite of genes is necessary for eye development, and therefore the term of "master control" gene may be inaccurate. Pax-6 is expressed as a transcription factor when neural ectoderm receives a combination of weak Sonic hedgehog (SHH) and strong TGF-Beta signaling gradients. Expression is first seen in the forebrain, hindbrain, head ectoderm and spinal cord followed by later expression in midbrain. This transcription factor is most noted for its ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Medical Genetics
Medical genetics is the branch tics in that human genetics is a field of scientific research that may or may not apply to medicine, while medical genetics refers to the application of genetics to medical care. For example, research on the causes and inheritance of genetic disorders would be considered within both human genetics and medical genetics, while the diagnosis, management, and counselling people with genetic disorders would be considered part of medical genetics. In contrast, the study of typically non-medical phenotypes such as the genetics of eye color would be considered part of human genetics, but not necessarily relevant to medical genetics (except in situations such as albinism). ''Genetic medicine'' is a newer term for medical genetics and incorporates areas such as gene therapy, personalized medicine, and the rapidly emerging new medical specialty, predictive medicine. Scope Medical genetics encompasses many different areas, including clinical practice ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colt (horse)
A colt is a male horse, usually below the age of four years. Description The term "colt" only describes young male horses and is not to be confused with foal, which is a horse of either sex less than one year of age. Similarly, a yearling is a horse of either sex between the ages of one and two. A young female horse is called a filly, and a mare once she is an adult animal. In horse racing, particularly for Thoroughbreds in the United Kingdom, a colt is defined as an uncastrated male from the age of two up to and including the age of four. The term is derived from Proto-Germanic *''kultaz'' ("lump, bundle, offspring") and is etymologically related to "child." An adult male horse, if left intact, is called either a " stallion" if used for breeding, or a horse (sometimes full horse); if castrated, it is called a gelding. In some cases, particularly informal nomenclature, a gelding under four years is still called a colt. A rig or ridgling is a male equine with a retained ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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