25,729 articles
Systemic capillary leak syndrome
Systemic capillary leak syndrome (SCLS), also known as Clarkson disease, is a rare disorder in which plasma leaks from capillaries into tissues in recurrent attacks, causing hypotension and widespread edema.
Systemic contact dermatitis
Systemic contact dermatitis is a widespread skin eruption in a person sensitized through skin contact when the allergen re-enters the body by mouth, injection, or implant.
Systemic Epstein-Barr virus-positive T-cell lymphoproliferative disease of childhood
Systemic EBV-positive T-cell lymphoproliferative disease of childhood, also called systemic EBV-positive T-cell lymphoma of childhood, is a rare, fulminant clonal proliferation of EBV-infected CD8-positive T cells after acute or chronic active EBV infection, prevalent in East Asia and Latin America.
Systemic inflammatory response syndrome
Systemic inflammatory response syndrome (SIRS), defined in 1991 by the ACCP/SCCM consensus, is two or more of fever/hypothermia, tachycardia, tachypnea, and abnormal white cell count; it underpinned Sepsis-1 and -2 definitions until Sepsis-3 (2016) removed it for poor specificity.
Systemic scleroderma
Systemic scleroderma (systemic sclerosis, SSc) is a rare autoimmune connective tissue disease with vasculopathy, autoantibodies, and fibrosis of skin and organs; subsets are limited (lcSSc, CREST) and diffuse (dcSSc).
Systemic-onset juvenile idiopathic arthritis
Systemic-onset juvenile idiopathic arthritis (sJIA), the pediatric form of Still's disease, is an autoinflammatory arthritis with quotidian fever, rash, and high IL-1/IL-6-driven inflammation, treated with anakinra, canakinumab, or tocilizumab.
Systems pharmacology model
A systems pharmacology model is a computational model that uses quantitative equations to predict drug effects, mechanisms, and safety across biological scales, balancing systems biology with PK/PD modeling.
Systole
Systole (Greek systolē, contraction): the cardiac cycle phase of heart-muscle contraction and blood ejection, from AV valve closure to semilunar valve closure; includes isovolumetric contraction and ejection; opposite of diastole.
Systolic Blood Pressure Intervention Trial
SPRINT (Systolic Blood Pressure Intervention Trial), NIH-funded RCT of 9361 high-risk adults without diabetes or stroke, showed systolic BP target <120 mm Hg cut cardiovascular events and death versus <140 mm Hg, with more hypotension, syncope, and kidney injury, reshaping 2017 and 2025 ACC/AHA guidelines.
T cell
A T cell, or T lymphocyte, is a white blood cell of the adaptive immune system that develops in the thymus and recognizes antigens through its T cell receptor.
T wave
T wave: the ECG deflection representing ventricular repolarization; normally upright except in aVR and V1, positive because repolarization runs opposite to depolarization; inversion, hyperacute, or alternans patterns mark ischemia and sudden-death risk.
T-B+NK- severe combined immunodeficiency due to gamma chain deficiency
T-B+NK- SCID due to gamma chain deficiency (SCID-X1, X-linked SCID) is an IL2RG-related immunodeficiency causing absent T and NK cells, neonatal infections, and failure to thrive; treated by HSCT or gene therapy.
T-B+NK+ severe combined immunodeficiency due to FOXN1 deficiency
T-B+NK+ SCID due to FOXN1 deficiency (nude/SCID, ORPHA:169095) is an autosomal recessive primary immunodeficiency with congenital athymia, alopecia totalis, and nail dystrophy; treated by thymus transplantation.
T-cell acute lymphoblastic leukemia
T-cell acute lymphoblastic leukemia (T-ALL), also called precursor T-lymphoblastic leukemia, is an aggressive leukemia of immature T-cell lymphoblasts; about 12-15% of pediatric and 25% of adult ALL, driven by NOTCH1 mutations, with MRD response as the key prognostic factor.
T-cell depletion
T-cell depletion (TCD) removes donor T cells from stem cell or bone marrow grafts, ex vivo or with antibodies, to prevent graft-versus-host disease after transplantation.
T-cell immunodeficiency with thymic aplasia
T-cell immunodeficiency with thymic aplasia (Nezelof syndrome, isolated congenital athymia, ORPHA:83471) is a rare recessive primary immunodeficiency with thymic aplasia, profound T-cell deficiency, normal or high immunoglobulins, and infantile infections; treated by thymus transplantation.
T-cell large granular lymphocyte leukemia
T-cell large granular lymphocyte leukemia (T-LGLL, T-LGL leukemia): an indolent clonal leukemia of cytotoxic CD8+ T cells causing neutropenia and anemia, marked by STAT3 mutations, treated with immunosuppression.
T-cell lymphoma
T-cell lymphoma: cancer of T cells, mostly non-Hodgkin lymphoma; under 15% of NHL; groups CTCL, PTCL, T-LBL/ALL; PTCL 5-year survival about 30-40%; classified by WHO-HAEM5 and ICC 2022.
T-cell prolymphocytic leukemia
T-cell prolymphocytic leukemia (T-PLL), also called T-cell chronic lymphocytic leukemia, is a rare aggressive mature T-cell leukemia with TCL1A/MTCP1 rearrangements, marked lymphocytosis, splenomegaly, alemtuzumab therapy, and poor prognosis.
T-cell/histiocyte-rich large B-cell lymphoma
T-cell/histiocyte-rich large B-cell lymphoma (THRLBCL), also called T-cell rich large B-cell lymphoma, is a rare aggressive DLBCL subtype with under 10% neoplastic B cells amid T cells and histiocytes, PD-L1-rich microenvironment, male predominance, and CAR T-cell resistance.
T-FAME-HF trial
T-FAME-HF (NCT04991857) is a University of Hong Kong randomized trial of a 16-week technology-based family-centered empowerment program versus HF education in 270 admitted heart failure patients; completed February 2026, no results posted.
T-REC study
T-REC (NCT06147128) is an Orsi Academy randomized blinded trial comparing proficiency-based progression with traditional training for robotic emergency conversion after vessel injury, in 48 Belgian surgical residents across four arms.
T. Franklin Williams
T. Franklin Williams (1921–2011) was an American geriatrician, professor at the University of Rochester, and second director of the National Institute on Aging from 1983 to 1991.
T1-CMR study
T1-CMR (International T1 Multicentre CMR Outcome Study, NCT02407197), King's College London-led observational study of 1,629 patients testing native T1, ECV, and LGE for predicting mortality in cardiomyopathy and CAD.
T1-weighted imaging
T1-weighted imaging is a magnetic resonance imaging technique in which tissue contrast is set mainly by T1 relaxation times, with fat bright, fluids dark, and gadolinium contrast agents best seen.
T1-weighted MRI
T1-weighted MRI, also known as 3D T1-weighted MRI, is a magnetic resonance imaging technique whose contrast is set by T1 relaxation times, making fat bright and water-rich tissue dark.
T2 mapping
T2 mapping is an MRI technique that converts tissue T2 relaxation times into pixel-by-pixel maps, used to measure heart muscle edema and knee cartilage degeneration.
T2 relaxometry
T2 relaxometry is a quantitative MRI technique measuring tissue T2 relaxation times in milliseconds instead of contrast images, used for myocardial edema, iron overload, myelin, and cartilage.
T2-weighted FLAIR MRI
T2-weighted FLAIR MRI is an MRI sequence that suppresses cerebrospinal fluid signal so white matter lesions, edema, and subarachnoid blood stand out, notably in multiple sclerosis.
T2-weighted MRI
T2-weighted MRI is a magnetic resonance imaging technique using long repetition and echo times so that fluid, edema, and many lesions appear bright against darker solid tissue.