Human health and medicine

Simufilam

Simufilam (PTI-125), an oral small molecule from Cassava Sciences/Filana Therapeutics binding filamin A; its two Phase 3 Alzheimer's trials (RETHINK-ALZ, REFOCUS-ALZ) failed, the program ended in 2025, and development now targets TSC-related epilepsy.

Simultaneous liver-kidney transplantation

Simultaneous liver-kidney transplantation (SLKT) is a single operation replacing both a failing liver and failing kidneys, accounting for roughly 10% of US liver transplants, a share that grew over 400% after MELD-based allocation began in 2002.

Simultaneous resection

Simultaneous resection is a surgical strategy in which a primary bowel tumor and its liver metastases, most often colorectal cancer, are removed in a single operation under one general anesthetic rather than in two staged procedures.

Simvastatin

Simvastatin, sold as Zocor, is a statin drug developed by Merck and approved in 1991 that lowers LDL cholesterol by blocking HMG-CoA reductase, the enzyme behind cholesterol synthesis.

Sina Hospital

Sina Hospital (بیمارستان سینا) is a public teaching hospital in central Tehran, founded under Naser al-Din Shah Qajar in the early 1870s and generally described as the oldest hospital in Tehran.

Sincalide

Sincalide (Kinevac) is a synthetic C-terminal octapeptide of cholecystokinin, FDA-approved since 1976, injected intravenously to stimulate gallbladder contraction, pancreatic secretion, and barium meal transit in diagnostic testing.

Oct 20, 2026

Sinding-Larsen-Johansson disease

Sinding-Larsen-Johansson disease (SLJ syndrome), a traction osteochondrosis causing pain at the inferior pole of the patella in active adolescents aged about 10-14; distinguished from Osgood-Schlatter disease by the injured end of the patellar tendon.

Single Embryo Transfer

Single embryo transfer (SET, elective eSET) places one IVF embryo per cycle to avoid multiple pregnancy; fresh live birth is lower than double transfer but cumulative outcomes match, and ESHRE, NICE, and ASRM recommend it for good-prognosis patients.

Single episode depressive disorder

Single episode depressive disorder is an ICD-11 diagnosis (code 6A70) for a person who has had exactly one depressive episode, with no prior episodes and no history of mania.

Single organ vasculitis

Single organ vasculitis (SOV), per the 2012 Chapel Hill nomenclature, is vasculitis of any vessel size confined to one organ without systemic vasculitis; focal forms are often cured by resection, diffuse forms need immunosuppression.

Oct 20, 2026

Single spontaneous delivery

Single spontaneous delivery (ICD-11 JB20; ICD-10 O80): birth of one neonate by unassisted, nonoperative vaginal delivery without induction, instruments, or cesarean; subcategories JB20.0 vertex and JB20.1 breech.

Single transverse palmar crease

Single transverse palmar crease, also called single palmar crease or formerly simian crease, is a fusion of the two transverse palm creases into one line, seen in about 1 in 30 people, twice as often in males, and associated with Down syndrome and other conditions.

Single umbilical cord artery

Single umbilical artery (SUA, two-vessel cord): a cord with one artery instead of two, seen in about 1% of pregnancies; associated with renal and cardiac anomalies, growth restriction, and increased stillbirth risk, managed with surveillance.

Single unprovoked seizure

A single unprovoked seizure is a seizure with no structural or metabolic cause, affecting about 150,000 US adults each year and carrying a 43% risk of recurrence by 2 years.

Single-balloon enteroscopy

Single-balloon enteroscopy is an endoscopic technique using an overtube with a single balloon to reach the small intestine for biopsy and therapy, mainly for obscure gastrointestinal bleeding.

Single-blind study

A single-blind study is a randomized trial design in which participants do not know which treatment they were assigned, while researchers do, reducing biased self-reporting of outcomes.

Single-Parent Family

A single-parent family is a household with children headed by one adult parent, most often a mother, arising mainly through divorce, separation, or births to unmarried mothers.

Single-payer healthcare

Single-payer healthcare: one public entity finances and pays for universal health coverage, as in Canada's Medicare and Taiwan's National Health Insurance; defined by CBO's four features, contrasted with multipayer systems.

Single-Tooth Dental Implants

A single-tooth dental implant is a titanium post placed in the jawbone to replace one missing tooth and its root, bonding to bone through osseointegration and carrying a crown.

Single-ventricle physiology

Single-ventricle physiology: one functional ventricle pumps to both lungs and body with mixing of blood. Treated by staged Norwood, Glenn, and Fontan palliation; Fontan circulation causes venous hypertension, liver disease, and transplant-dependent failure.

Single-voxel spectroscopy

Single-voxel spectroscopy (SVS) is a magnetic resonance spectroscopy technique that acquires a metabolite spectrum from one small, precisely defined tissue volume, applied mostly to the brain.

Singleton-Merten dysplasia

Singleton-Merten dysplasia, also known as Singleton-Merten syndrome, is a rare autosomal dominant condition causing abnormal tooth development, thoracic aorta calcification, and osteoporosis, first described in 1973.

Sino-Nasal Outcome Test

The Sino-Nasal Outcome Test, or SNOT-22, is a validated 22-item questionnaire that patients with chronic rhinosinusitis complete, scored 0 to 110 with higher scores indicating worse disease.

Sinoatrial block

Sinoatrial block (SA block) is a cardiac conduction disturbance in which the sinus node's impulse fails to reach the atria, so no P wave appears on the ECG.

Sinoatrial node

The sinoatrial node, also called the SA node, is a cluster of cells in the right atrium that generates the heartbeat's electrical rhythm as the heart's natural pacemaker.

Sinoatrial node dysfunction and deafness

Sinoatrial node dysfunction and deafness (SANDD, OMIM 614896) is an ultra-rare autosomal recessive CACNA1D channelopathy combining congenital severe-to-profound deafness with bradycardia, syncope, and pacemaker-based management.

Sinopharm Wuhan inactivated COVID-19 vaccine (WIBP)

WIBP-CorV is the Sinopharm Wuhan inactivated COVID-19 vaccine (Vero cell), developed with the CAS Wuhan Institute of Virology from strain WIV04; conditionally approved in China February 2021, phase 3 efficacy 72.8% against symptomatic COVID-19, WHO EUL dossier withdrawn in 2022.