25,729 articles
Symptoms of endometriosis
Symptoms of endometriosis include severe dysmenorrhea, chronic pelvic pain, deep pain during sex, heavy bleeding, and infertility; symptoms usually begin in adolescence and often improve after menopause.
Synapse
A synapse, or synaptic junction, is where a neuron passes an electrical or chemical signal to another neuron or effector cell; chemical synapses release neurotransmitters, electrical ones pass current directly.
Synapsin
Synapsins (synapsin I, II, III; SYN1, SYN2, SYN3) are neuron-specific phosphoproteins coating synaptic vesicles, regulating neurotransmitter release via phosphorylation, and modulating neuronal development, plasticity, and neurological disease.
Synaptic plasticity
Synaptic plasticity, also called Hebbian plasticity, LTP and LTD, is activity-dependent change in synaptic strength considered the main mechanism of learning and memory storage, spanning potentiation, depression, homeostatic scaling, and metaplasticity.
Synaptic Potentials
Synaptic potentials are graded voltage changes across pre- or postsynaptic membranes, chiefly EPSPs and IPSPs produced by ligand-gated ion channels, that summate temporally and spatially to decide whether a neuron fires.
Synaptic pruning
Synaptic pruning is the developmental elimination of excess neural synapses, driven by activity and executed by microglia, astrocytes, and OPCs via complement and other immune signals; dysregulation links to schizophrenia and autism.
Synaptic scaling
Synaptic scaling, or homeostatic synaptic scaling, is a slow non-Hebbian plasticity first described by Turrigiano in 1998 in which neurons globally multiply all excitatory synapse strengths up or down, via AMPA receptor trafficking, to stabilize firing.
Synaptogenesis
Synaptogenesis is the formation of synapses between neurons, via growth-cone contact and recruitment of scaffold and cell adhesion proteins such as PSD95, neurexin, and neuroligin; it peaks postnatally in rodents (P7–P14) and continues throughout life, with mutations in SHANK and SYNGAP1 linked to autism and intellectual disability.
Synaptotagmin
Synaptotagmin (SYT): a family of 17 mammalian vesicle membrane proteins with tandem C2 domains that act as Ca2+ sensors for exocytosis; Syt1/2/9 trigger fast synchronous neurotransmitter release, Syt7 asynchronous release and facilitation.
Synaptotropic hypothesis
Synaptotropic hypothesis: Vaughn's 1989 proposal that synaptic inputs direct dendritic and axonal arbor growth by selectively stabilizing filopodia on which synapses form; tested in Xenopus and zebrafish optic tectum.
Syncope (medicine)
Syncope (fainting) is transient loss of consciousness from cerebral hypoperfusion, with rapid onset and spontaneous recovery. Covers reflex, cardiac, and orthostatic causes, prevalence near 40%, evaluation, and ACC/AHA/HRS versus ESC guidelines.
Syncope or collapse
Syncope, also known as fainting or collapse, is a brief loss of consciousness from reduced blood flow to the brain, resolving quickly without treatment and affecting one-third to one-half of people.
Syndactyly
Syndactyly, also called webbed fingers or toes, is a congenital fusion of adjacent digits occurring in about 1 in 2,000 births, classified simple or complex, isolated or syndromic, and treated by surgical release.
Syndactyly type 1
Syndactyly type 1 (SD1) is a common hereditary limb malformation with webbing between the third and fourth fingers and/or second and third toes, inherited dominantly.
Syndactyly type 2
Syndactyly type 2, or synpolydactyly (SPD, Vordingborg type), a rare autosomal dominant non-syndromic limb malformation combining 3/4 finger and 4/5 toe webbing with duplicated digits in the web; SPD1 caused by HOXD13 polyalanine expansions, SPD2 by FBLN1, SPD3 mapped to 14q11.2-q13.
Syndactyly type 6
Syndactyly type 6 (mitten-type syndactyly, ORPHA:295012) is a rare non-syndromic congenital digit fusion: unilateral fusion of fingers 2-5 with knot-like distal phalanges and 2nd-3rd toe fusion; inheritance listed as autosomal dominant or unknown.
Syndactyly-telecanthus-anogenital and renal malformations syndrome
STAR syndrome (OMIM 300707), an ultra-rare X-linked dominant malformation disorder from CCNQ/FAM58A loss-of-function on Xq28, causing toe syndactyly, telecanthus, and anogenital and renal malformations in females, likely lethal in males.
Syndrome
Syndrome: a group of signs and symptoms occurring together and characterizing an abnormality, from Greek syndromē 'running together'. Distinguished from disease (known cause) and disorder; examples include Down and metabolic syndrome.
Syndrome of inappropriate antidiuretic hormone secretion
SIADH, also called syndrome of inappropriate antidiuresis (SIAD), is excessive ADH effect causing euvolemic hyponatremia; diagnosed by concentrated urine with exclusion of other causes, treated with fluid restriction or hypertonic saline.
Syndromic congenital sodium diarrhea
Syndromic congenital sodium diarrhea (syndromic congenital tufting enteropathy, OMIM 270420) is a rare autosomal recessive SPINT2-related intestinal disorder with neonatal sodium-losing diarrhea, choanal atresia, and corneal erosions.
Syndromic craniosynostoses
Syndromic craniosynostoses: genetic disorders with premature cranial suture fusion plus other anomalies, mainly Apert, Crouzon, Pfeiffer, Muenke, Saethre-Chotzen, and craniofrontonasal syndromes, mostly FGFR gene mutations, requiring multidisciplinary care.
Synergism
Synergism (synergy, from Greek synergia) is an interaction in which a combined effect exceeds the additive prediction of individual effects; defined in toxicology, pharmacology, ecology, and solvent extraction chemistry.
Synergistic divergence
Synergistic divergence is a rare congenital ocular motility disorder in which the affected eye abducts further on attempted adduction, often classified as type 4 Duane syndrome.
Synflorix
Synflorix (PCV10, PHiD-CV) is GSK's 10-valent pneumococcal conjugate vaccine for children 6 weeks to 5 years, covering serotypes 1, 4, 5, 6B, 7F, 9V, 14, 18C, 19F, 23F; EU-authorized 2009, WHO-prequalified 2009-2010, used mainly in emerging countries.
Syngamosis
Syngamosis is a parasitic disease of birds, and occasionally mammals and humans, caused by gapeworms in the upper respiratory tract, causing gasping, coughing, and breathing difficulty.
SYNGAP1-related developmental and epileptic encephalopathy
SYNGAP1-related developmental and epileptic encephalopathy (SYNGAP1-DEE), also called SYNGAP1-related intellectual disability, is a rare genetic disorder causing developmental delay, epilepsy, and autism, usually with seizures beginning around age 2.
Synovectomy
Synovectomy is surgical, arthroscopic, or radiation removal of a joint's inflamed synovial membrane, first proposed in 1900, used for rheumatoid arthritis, PVNS, and hemophilia; it relieves pain in about 75% of patients but the synovium regrows.
Synovial biopsy
Synovial biopsy is a diagnostic procedure that removes a small sample of the synovium, a joint's lining membrane, when fluid analysis and imaging cannot identify the cause of joint inflammation.
Synovial bursa
Synovial bursa (pl. bursae): thin synovial membrane-lined, fluid-filled sacs, about 160 in the adult body, mostly near large joints, that reduce friction between bone, tendon, muscle, and skin; distinct from adventitious bursae.
Synovial chondromatosis
Synovial chondromatosis (synovial osteochondromatosis): rare benign condition where cartilage nodules form in the joint synovium, most often the knee, men 4:1, treated by loose body removal and synovectomy.