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an abnormality of development; in pathology, alteration in size, shape, and organization of adult cells. See also dysgenesis. adj., adj dysplas´tic.
bronchopulmonary dysplasia chronic lung disease of premature infants with hyaline membrane disease who have needed high concentrations of oxygen and assisted ventilation. Factors related to its development include alveolar damage due to hyaline membrane disease, oxygen toxicity, positive pressure ventilation, and endotracheal intubation. Treatment includes supportive measures and oxygen therapy. Recovery and normal pulmonary function usually occur by the age of 6 months to 1 year; however, some infants may exhibit limited tolerance to exercise.
craniometaphyseal dysplasia metaphyseal dysplasia associated with overgrowth of the head bones, leonine facies, and increased distance between the eyes.
cretinoid dysplasia a developmental abnormality characteristic of cretinism, consisting of retarded ossification and smallness of the internal and reproductive organs.
cystic renal dysplasia renal dysplasia in which there are cysts.
developmental dysplasia of the hip (DDH) instability of the hip joint leading to dislocation in the neonatal period. Although it may be associated with various neuromuscular disorders, such as myelodysplasia, or occur in utero, it most commonly occurs in neurologically normal infants and is multifactorial in origin. Usually there is laxity of the hip ligaments. Most affected infants are first-born children and 30 to 50 per cent present in the breech position. About 90 per cent of those affected are girls. The condition was formerly called congenital dislocation of the hip, but because the dislocation is not normally present at birth but develops later, the term developmental dysplasia of the hip is preferred.
ectodermal dysplasia any of a group of hereditary disorders involving absence or deficiency of tissues and structures derived from the embryonic ectoderm, such as teeth, hair, nails, and certain glands.
fibromuscular dysplasia dysplasia with fibrosis of the muscular layer of an artery wall, with collagen deposition and hyperplasia of smooth muscle, causing stenosis and hypertension. It most commonly occurs in the renal arteries and is a major cause of renovascular hypertension.
fibrous dysplasia of bone thinning of the cortex of bone and replacement of bone marrow by gritty fibrous tissue containing bony spicules, causing pain, disability, and gradually increasing deformity; it may affect a single bone (monostotic fibrous dysplasia) or several or many bones (polyostotic fibrous dysplasia). When associated with melanotic pigmentation of the skin and endocrine disorders, it is known as albright's syndrome.
metaphyseal dysplasia a disturbance in enchondral bone growth, failure of modeling causing the ends of the shafts to remain larger than normal in circumference.
oculodentodigital dysplasia a rare hereditary condition, characterized by bilateral microphthalmos, abnormally small nose with anteverted nostrils, hypotrichosis, dental anomalies, camptodactyly, syndactyly, and missing phalanges of the toes.
renal dysplasia a congenital disorder of the kidney, with persistence of cartilage, undifferentiated mensenchyme, and immature collecting tubules, as well as with abnormal lobar organization and nearly always cysts; it may be unilateral or bilateral and total or subtotal. Total bilateral dysplasia is rapidly fatal in the neonatal period, while milder disease may be asymptomatic.
retinal dysplasia a general term for a congenital defect resulting from the abnormal growth and differentiation of a retina that fails to develop into functioning tissue.
an overgrowth of glial tissue compensating for aplasia of sensory elements.
1. pertaining to the retina.
2. the aldehyde of retinol, having vitamin A activity. One isomer(11-cis-retinal) combines with opsin in the retinal rods (scotopsin) to form rhodopsin (visual purple); another, all-trans-retinal, or visual yellow, results from the bleaching of rhodopsin by light, in which the 11-cis-form is converted to the all-trans-form. Retinal also combines with opsins in the retinal cones to form the three pigments responsible for color vision.
inherited as a recessive character in foals.
central progressive retinal atrophy
a disease of the retinal pigmented epithelium, generally in middle-aged Labrador retrievers, Border collies, Golden retrievers, Irish setters, and English springer spaniels. There are pigmentary changes in the tapetal fundus, with attenuation of retinal vasculature, and atrophy of the optic disk. Day vision is affected first, followed by impairment, but not always blindness, in any situation. Called also CPRA.
see retinal detachment.
retinal dialysis, retinal disinsertion
separation of the sensory retinal layer from the pigment layer at the ora ciliaris retinae.
a congenital anomaly in many species, consisting of an abnormal differentiation of retinal cells and proliferation of photoreceptors, forming rosettes. May be caused by viral infections such as feline panleukopenia, bluetongue, bovine virus diarrhea and canine herpesvirus; an inherited defect in some breeds of dogs and cattle.
retinal ganglionic cell layer
the layer of the retina which contains ganglion cell bodies.
occur in association with many systemic diseases and intoxications in most species, including ethylene glycol poisoning, ehrlichiosis, severe anemia and thromboembolic meningoencephalitis in cattle.
inner retinal nuclear layer
the layer of the retina which contains the cell bodies of bipolar neurons and association neurons.
light-induced retinal degeneration
a phototoxic degeneration in rats and mice caused by exposure to continuous light and high temperatures.
retinal nuclear layer
the layer of the retina which includes inner and outer nuclear layers of the retina.
retinal optic nerve fiber layer
retinal layer of axonal processes of the ganglion cells as they approach the optic papilla and emerge as the optic nerve.
outer retinal nuclear layer
the layer of the retina which contains the cell nuclei of the photoreceptor cells.
retinal photoreceptor layer
the retinal layer which contains rods and cones, modified neuronal processes of the photoreceptor rod and cone cells.
retinal pigment epithelial layer
retinal layer just beneath the choroidal basal complex of the eye; probably serves as a store of vitamin A. Long cellular processes extend to and between the photoreceptor cells in the next layer.
retinal plexiform layer
the retinal layer which includes inner and outer plexiform layers; both consist of a network of cell processes of adjacent nerve cells, especially photoreceptor and ganglion cells.
progressive retinal atrophy
a group of inherited, degenerative diseases of the retina, occurring most commonly in dogs and consisting of a progressive, noninflammatory degeneration or dysplasia of rods and cones or purely cones, leading to blindness. Specific features, such as age of onset, pattern of degeneration, and ultrastructural and biochemical changes vary between the many breeds in which the disease is found. Night blindness followed by a loss of day vision are clinical signs common to most. There may also be an associated cataract formation. See also central progressive retinal atrophy (above), cone dysplasia, rod-cone dysplasia. Called also PRA.
progressive retinal degeneration
in one system of classification, a term encompassing a range of retinal disorders otherwise referred to as various types of retinal atrophy, retinal dysplasias or retinal degenerations. The inherited rod-cone dysplasias of dogs and cats are included in Type I; pigment epithelial dystrophy (central progressive atrophy) is Type II; and hemeralopia of Alaskan malamutes and miniature poodles is Type III. Called also PRD.
sudden acquired retinal degeneration
a nonspecific degeneration of rods and cones that progresses to complete retinal atrophy and blindness in mature dogs. The cause is unknown. Called also silent retina syndrome, metabolic toxic retinopathy, SARD.