72,234 articles
Facial skeleton
Facial skeleton (viscerocranium, splanchnocranium): the 14 bones at the front of the human skull, including the maxilla and the mandible, the skull's only movable bone; supports the face and houses sensory and respiratory structures.
Facies (medicine)
Facies (medicine): the characteristic facial appearance suggesting a specific disease, e.g., elfin facies of Williams syndrome; Latin for face; a MeSH-indexed physical examination sign, not to be confused with facial expression.
Facilitated diffusion
Facilitated diffusion (facilitated transport, carrier-mediated diffusion): passive membrane transport through channel or carrier proteins (GLUT uniporters, ion channels) down the electrochemical gradient, saturating at Vmax with no ATP use.
Facilitator of iron transport 2
Facilitator of iron transport 2 (Fit2p, FIT2, YOR382W) is a GPI-anchored Saccharomyces cerevisiae cell wall mannoprotein, Aft1p-regulated, that retains siderophore-iron and aids uptake of ferrichrome and ferrioxamine B; unrelated to mammalian lipid-droplet FIT2.
Faciocardiorenal syndrome
Faciocardiorenal syndrome, also called Eastman-Bixler syndrome, is a very rare autosomal recessive disorder marked by intellectual disability, horseshoe kidney, and congenital heart defects, first described by Eastman and Bixler in 1977.
Facioscapulohumeral muscular dystrophy
Facioscapulohumeral muscular dystrophy (FSHD), also called Landouzy-Dejerine dystrophy, is an autosomal dominant muscle disease caused by DUX4 derepression via D4Z4 contraction (FSHD1) or SMCHD1-related hypomethylation (FSHD2), affecting face, shoulders, and upper arms.
Factitious disorder
Factitious disorder (Munchausen syndrome; FDIA, ICD-11 6D51): intentional feigning or induction of illness without external reward, distinct from malingering and somatic symptom disorder; about 1% clinical prevalence, 6-9% mortality in proxy cases.
Factitious disorder imposed on another
Factitious disorder imposed on another (FDIA), formerly Munchausen syndrome by proxy, is a DSM-5-TR disorder in which a caregiver falsifies or induces illness in a dependent, usually a child, for attention rather than material gain.
Factitious disorder imposed on self
Factitious disorder imposed on self, formerly Munchausen syndrome, is a mental disorder in which a person deliberately fakes or induces illness in themselves to assume the sick role, without external rewards, distinguished from malingering by internal motivation.
Factor H
Factor H (CFH) is a 150-kDa, 20-domain soluble plasma glycoprotein that regulates the complement alternative pathway by competing with factor B, accelerating convertase decay, and serving as factor I cofactor; linked to aHUS, AMD, and C3 glomerulopathy.
Factor H binding protein
Factor H binding protein (fHbp, GNA1870, LP2086) is a 27-kDa Neisseria meningitidis surface lipoprotein that binds human complement factor H to evade killing and serves as the key antigen in the licensed MenB vaccines Bexsero and Trumenba.
Factor V Leiden
Factor V Leiden (FVL, factor V R506Q) is the most common inherited thrombophilia, an F5 gene mutation causing activated protein C resistance; carried by 3–8% of Europeans, it raises venous thromboembolism risk but only marginally increases recurrence.
Factor VIII
Factor VIII (antihemophilic factor) is the clotting cofactor deficient in hemophilia A; carried by von Willebrand factor, half-life 8–16 h, cloned 1984, recombinant since 1992, extended half-life and mimetic alternatives now available.
Factor X
Factor X (Stuart–Prower factor) is a vitamin K-dependent liver serine protease, first enzyme of the common coagulation pathway, encoded by F10 on 13q34; its inherited deficiency affects about 1 per million people.
Facultative anaerobic organism
Facultative anaerobe (facultative anaerobic organism): microbe that grows with or without oxygen, using aerobic respiration when O2 is present and fermentation or anaerobic respiration otherwise; examples include E. coli, staphylococci, and yeasts.
Facundo Batista
Facundo D. Batista is an Argentinian immunologist who studies B cells, leads research at the Ragon Institute and MIT, and was elected to the National Academy of Medicine in 2025.
FAD and FMN biosynthesis
FAD and FMN biosynthesis is the two-step enzymatic pathway converting riboflavin (vitamin B2) into FMN and FAD: riboflavin kinase phosphorylates riboflavin, then FAD synthetase adenylylates FMN.
Fad diet
Fad diet, also called crash diet: an eating plan promoted as the fastest way to lose weight without standard dietetic basis. Evidence shows popular diets produce similar ~5% short-term loss, weight regain, and health risks.
FADD
FADD (Fas-associated via death domain) is a 208-amino-acid adaptor protein with N-terminal DED and C-terminal DD domains that assembles the death-inducing signaling complex, recruiting caspase-8/10 to death receptors like Fas, TRAILR, and TNFR1, and also regulates cell cycle, necroptosis, and tumor immunity.
Fadi G. Lakkis
Fadi G. Lakkis is a transplantation immunologist and physician-scientist known for work on innate allorecognition and memory T cells in transplant rejection, long at the Starzl Transplantation Institute in Pittsburgh and now at Stanford.
FADS1
FADS1 (fatty acid desaturase 1, delta-5 desaturase gene) at 11q12-q13.1 encodes D5D, converting DGLA to arachidonic acid and ETA to EPA; common haplotypes strongly determine blood PUFA levels, lipid traits, and disease risk.
FaDu
FaDu (CVCL_1218, ATCC HTB-43) is a human hypopharyngeal squamous cell carcinoma cell line established in 1968 from a 56-year-old male patient from Calcutta, India; a standard HNSCC model with CDKN2A and TP53 mutations used in cisplatin, radiation, and 3D culture studies.
Faecal calprotectin
Faecal calprotectin: stool measure of the neutrophil S-100 protein calprotectin, used to distinguish IBD from IBS and monitor IBD activity; typical cut-off 50 µg/g, high negative predictive value.
Faecal egg count reduction test
Faecal egg count reduction test (FECRT), also called drench-fecal egg count reduction, a veterinary field test comparing nematode egg counts before and after anthelmintic treatment; reduction below 95% (90% in pigs) indicates anthelmintic resistance in livestock and horses.
Faecal incontinence
Faecal (fecal, bowel) incontinence is the recurrent involuntary passage of stool, affecting about 8% of adults worldwide, more often women and older people; managed first with diet, medication, and pelvic floor exercises.
Faecal smearing
Faecal smearing (便汚染), ICD-11 code ME07.0, is a specified subtype of faecal incontinence (ME07), classified alongside incomplete defaecation and faecal urgency, with encopresis excluded.
Faecal urgency
Faecal urgency, also called fecal urgency, is a sudden, compelling need to defecate that is difficult to defer, and a major risk factor for fecal incontinence.
Faecalibacterium
Faecalibacterium is a genus of strictly anaerobic gut bacteria, among the most abundant in healthy adults and a major producer of butyrate, which fuels the gut lining.
Faecalibacterium prausnitzii
Faecalibacterium prausnitzii, formerly Fusobacterium prausnitzii, is an anaerobic Oscillospiraceae bacterium, a dominant human gut commensal and major butyrate producer, depleted in IBD and a next-generation probiotic candidate.
Fagaceae
Fagaceae (beech family), oaks Quercus, beeches Fagus, chestnuts Castanea; 8 genera, ~1,000 Northern Hemisphere tree species; nuts in woody cupules; major hardwood timbers.