Human health and medicine

Smallpox vaccine

Smallpox vaccine: vaccinia-based vaccine created by Edward Jenner in 1796, the first successful vaccine; 95% effective historically, it enabled WHO's 1980 eradication of smallpox and now exists as stockpiled ACAM2000, JYNNEOS, and APSV.

SMARCA4-deficient sarcoma of thorax

SMARCA4-deficient sarcoma of thorax, also called thoracic SMARCA4-deficient undifferentiated tumor (SMARCA4-UT), is a rare aggressive adult thoracic tumor with SMARCA4/SMARCA2 loss, rhabdoid morphology, strong smoking and male association, and median survival of months.

SMART study

SMART study (SNP-based Microdeletion and Aneuploidy RegisTry, NCT02381457): Natera-funded, 21-center prospective registry of over 20,000 pregnancies evaluating SNP-based cfDNA screening; reported 83.3% sensitivity and 52.6% PPV for 22q11.2 deletion syndrome with genetic confirmation of all samples.

Oct 20, 2026

SMART-RESCUE study

SMART-RESCUE (NCT02985008) is a Korean multicenter retrospective and prospective registry of 1,247 cardiogenic shock patients from 12 centers (2014-2018), reporting 33.6% in-hospital mortality and spawning risk scores and substudies.

SMARTT study

SMARTT (Surveillance Monitoring for ART Toxicities) is a PHACS prospective cohort study, since 2007 at 22 US sites, monitoring safety of in utero antiretroviral exposure in HIV-exposed uninfected children using a trigger-based design.

Smartwatch

Smartwatch: wrist-worn wearable computer with touchscreen, sensors, and apps, pairing with iPhone or Android. Tracks heart rate via PPG, activity, and sleep; used in remote patient monitoring; FDA warns against noninvasive glucose claims.

SMC study

SMC study: the Swedish Mammography Cohort, a population-based prospective cohort of 61,433 women recruited via mammography screening in Uppsala and Västmanland counties from 1987, now part of SIMPLER with COSM.

Smear examination

A smear examination is a diagnostic method in which cells or microorganisms from a specimen are fixed, stained, and examined under a microscope, mainly for tuberculosis and malaria.

Smear microscopy

Smear microscopy is the light-microscopic examination of stained smears, most often sputum, to detect acid-fast bacilli such as Mycobacterium tuberculosis; it remains the primary TB diagnostic in many high-burden settings.

Smegma

Smegma: a natural buildup of sebum, dead skin cells, and moisture under the foreskin or around the clitoral hood; harmless, not an STI, and not carcinogenic despite a long medical myth.

Oct 20, 2026

Smell

Smell, or olfaction, is the chemical sense by which gaseous odorant molecules are detected and identified, mediated by the olfactory nerve and closely coupled to taste in flavor perception.

Smell training

Smell training, also called olfactory training, is a rehabilitation therapy in which patients sniff a fixed set of odorants twice daily for months to recover lost smell.

Smelling salts

Smelling salts, also called ammonia inhalants or aromatic ammonia, are ammonium carbonate preparations releasing ammonia gas to trigger an inhalation reflex; historically used for fainting since the 13th century, now common in sports despite weak performance evidence and FDA warnings.

SMET12

SMET12 is a recombinant anti-EGFR/CD3 bispecific antibody and T-cell engager developed by China's Zhejiang Shimai Pharmaceutical, in trials for EGFR-positive solid tumors including lung cancer and esophageal cancer.

SMIS-Max trial

SMIS-Max (NCT06081192) is a single-center prospective trial at the Federal University of Goias, Brazil, testing a partially guided protocol for six Straumann Ti-Zr one-piece mini implants retaining maxillary overdentures, with placement accuracy as the primary outcome.

Smith machine

Smith machine: guided-barbell gym equipment with a fixed vertical or angled bar path, safety hooks, and stops. Invented in the 1950s from Jack LaLanne's design by Rudy Smith; free weight squats show 43% higher overall EMG.

Smith-Magenis syndrome

Smith-Magenis syndrome (SMS, 17p11.2 deletion syndrome) is a rare neurodevelopmental disorder caused by a 17p11.2 deletion (~90%) or RAI1 variant (~10%), with intellectual disability, inverted melatonin secretion, sleep disturbance, and self-injurious behavior.

Smith-McCort dysplasia

Smith-McCort dysplasia (SMC, OMIM 607326/615222), a rare autosomal recessive spondylo-epi-metaphyseal dysplasia with barrel chest, double-humped vertebrae, lacy iliac crests, and normal intelligence, unlike DMC; caused by DYM or RAB33B variants.

Smoking

Smoking: inhalation of burning tobacco, mainly via cigarettes; over 7 million deaths yearly, 1.2 billion users, global prevalence down from 33.1% (2000) to 19.5% (2024); distinct from vaping and smokeless tobacco.

Smoking cessation

Smoking cessation: quitting tobacco smoking via behavioral counseling, quitlines, and medications (NRT, bupropion, varenicline, cytisine, e-cigarettes). Combined treatment roughly doubles quit rates; WHO issued a 2024 clinical guideline.

Smoking topography

Smoking topography is a clinical research method measuring how a smoker puffs on a cigarette, including puff count, volume, duration, and interpuff interval, to quantify actual smoke exposure.

Oct 20, 2026

Smoldering systemic mastocytosis

Smoldering systemic mastocytosis (SSM) is a nonadvanced WHO subtype of systemic mastocytosis defined by two or more B-findings without C-findings, higher mast cell burden than indolent SM, about 9% progression risk, and antimediator therapy.

Smooth muscle

Smooth muscle: involuntary, non-striated muscle of hollow organs and vessels; single-unit and multi-unit types; myosin light chain phosphorylation via Ca2+-calmodulin-MLCK; latch state sustains tone cheaply; VSMC plasticity drives vascular disease.

Smooth Muscle Contraction

Smooth muscle contraction: calcium-calmodulin activation of myosin light-chain kinase phosphorylates myosin regulatory light chains, driving actin-myosin sliding anchored at dense bodies and focal adhesions; also caldesmon pathway, Rho kinase calcium sensitization, latch-bridges.

Smooth pursuit

Smooth pursuit: continuous eye movement tracking a slowly moving object to hold its image on the fovea; requires a moving target, has 100–125 ms latency, and involves MT/MST, FEF, cerebellum, and vestibular nucleus pathways.

Smouldering myeloma

Smouldering myeloma (smouldering multiple myeloma, SMM) is an asymptomatic precursor of multiple myeloma with 10–60% clonal bone marrow plasma cells and no CRAB damage; high-risk SMM progresses at 40–50% in 2 years and daratumumab was FDA-approved for it in 2025.

SMS DPpostop trial

SMS DPpostop (NCT04313855) was a completed 306-patient diagnostic trial at Groupe Hospitalier Paris Saint Joseph testing SMS text messaging plus the DN2 questionnaire for early detection of postoperative neuropathic pain after ambulatory surgery; no results posted.

Snakebite

Snakebite envenoming, a WHO category A neglected tropical disease, causes 4.5–5.4 million bites and 81,000–138,000 deaths yearly, mostly in South Asia and Africa; antivenom is the only effective treatment.

SNAP trial

SNAP trial names several clinical trials: the weight-gain prevention RCT (NCT01183689) in 599 young adults, the Staphylococcus aureus Network Adaptive Platform trial (NCT05137119), a nab-paclitaxel breast cancer phase II trial, a pregnancy nicotine-replacement trial, and the SNaPP anesthesia trial.