Human health and medicine

LCAT deficiency

LCAT deficiency (lecithin-cholesterol acyltransferase deficiency), including familial LCAT deficiency (FLD) and fish-eye disease (FED), is a rare autosomal recessive lipoprotein disorder causing corneal opacities, hemolytic anemia, very low HDL-C, and progressive renal failure.

LDIR-CT-AD trial

LDIR-CT-AD (NCT03597360), a 2019 Canadian single-arm pilot trial treating four advanced Alzheimer's dementia patients with repeated 40 mGy brain CT scans, reporting qualitative cognitive improvements and minor quantitative gains.

LDL apheresis

LDL apheresis is an extracorporeal treatment that removes LDL cholesterol and lipoprotein(a) from the blood, used for severe familial hypercholesterolemia uncontrolled by drugs, with sessions repeated weekly or biweekly.

LDR2402

LDR2402 is an investigational small interfering RNA drug for mild to moderate hypertension, developed by Leaderna Therapeutics, a subsidiary of China's HitGen, now in phase 2.

Le Fort fracture of skull

Le Fort fracture of skull: bilateral midface fracture separating facial skeleton from cranial base; types I (horizontal), II (pyramidal), III (craniofacial dissociation); pterygoid plate fracture unifies all; from René Le Fort's 1901 cadaver experiments.

Le Fort Osteotomy

Le Fort osteotomy: surgical cuts of the maxilla along René Le Fort's 1901 fracture lines (Le Fort I, II, III). Le Fort I repositions the tooth-bearing maxilla for malocclusion, sleep apnea, and midface deficiency; complications about 6.4%.

Lead extraction (cardiology)

Lead extraction is the percutaneous removal of a pacemaker or defibrillator lead implanted for more than one year, using locking stylets, sheaths, or laser energy, most often for infection.

Lead implantation (cardiology)

Lead implantation is the cardiology procedure of placing insulated electrode wires into the heart chambers and connecting them to a pacemaker, ICD, or CRT pulse generator.

Lead poisoning

Lead poisoning, also called lead toxicity, is the toxic condition caused by absorption of lead into blood and tissues, particularly harmful to young children and women of child-bearing age.

LEAD-1 trial

LEAD-1 SU (NCT00318422), first trial of the LEAD liraglutide phase 3 program: 26-week, five-arm trial adding liraglutide 0.6–1.8 mg, rosiglitazone, or placebo to glimepiride in 1041 type 2 diabetes patients; HbA1c fell 1.1% with higher doses.

LEAD-2 trial

LEAD-2 (NCT00318461) trial: 26-week phase-III randomized trial by Nauck et al. testing liraglutide 0.6–1.8 mg added to metformin versus glimepiride or placebo in 1,091 type 2 diabetes patients; HbA1c −1.0%, weight loss, low hypoglycemia.

LEAD-3 trial

LEAD-3 (LEAD-3 Mono, NCT00294723) is a phase III trial comparing liraglutide 1.2 and 1.8 mg with glimepiride 8 mg monotherapy in 746 patients with early type 2 diabetes over 52 weeks plus a 2-year extension, showing greater HbA1c, weight, and blood pressure benefits with liraglutide.

LEAD-4 trial

LEAD-4 (NCT00333151), a Novo Nordisk phase 3 trial in the LEAD program, tested liraglutide 1.2 or 1.8 mg versus placebo added to metformin plus rosiglitazone in 533 type 2 diabetes patients over 26 weeks.

LEAD-5 trial

LEAD-5 (LEAD-5 met+SU), NCT00331851, a 26-week Novo Nordisk-funded trial comparing liraglutide 1.8 mg with placebo and insulin glargine added to metformin and glimepiride in 581 type 2 diabetes patients across 107 centers in 17 countries.

LEAD-6 trial

LEAD-6 (Liraglutide Effect and Action in Diabetes 6, NCT00518882) was a 2009 Lancet-published 26-week open-label trial comparing liraglutide 1.8 mg once daily with exenatide 10 µg twice daily in type 2 diabetes; liraglutide cut HbA1c more (−1.12% vs −0.79%) with less nausea and hypoglycemia.

Leaden paralysis

Leaden paralysis is the sensation of arms or legs feeling heavy as lead during depressive episodes; a DSM-IV atypical features specifier criterion and ICD-11 term, not true muscular paralysis, linked to bipolar and chronic atypical depression.

LEADER® trial

LEADER (Liraglutide Effect and Action in Diabetes: Evaluation of Cardiovascular Outcome Results), NCT01179048: randomized double-blind trial of liraglutide 1.8 mg daily vs placebo in 9,340 high-risk type 2 diabetes patients; MACE HR 0.87, reduced CV and all-cause death.

LEADERS trial

LEADERS (Limus Eluted From A Durable Versus ERodable Stent Coating) trial: 1,707-patient randomized noninferiority trial comparing biodegradable-polymer biolimus-eluting stents with durable-polymer sirolimus-eluting stents; noninferior at 9 months, fewer very late stent thromboses at 5 years.

Leadless pacemaker implantation

Leadless pacemaker implantation is a catheter-based procedure that places a self-contained pacemaker capsule inside the right ventricle, avoiding the leads and generator pocket of conventional pacemakers.

Lean (drug)

Lean, also called purple drank, sizzurp, or dirty Sprite, is a Houston-originated recreational drink of codeine-promethazine cough syrup mixed with soda and candy, popularized by Southern hip hop and linked to respiratory depression, addiction, and overdose deaths.

Leana Wen

Leana Wen, American emergency physician and public health professor at George Washington University; former Baltimore health commissioner (2015-2018) and Planned Parenthood president (2018-2019); CNN medical analyst and Washington Post columnist known for COVID-19 commentary.

LEARNERS study

LEARNERS (NCT06589323) is a completed prospective observational cohort study at Gemelli IRCCS, Rome, defining the learning curve for residents in TTFM and HRUS graft assessment during CABG; endpoint reached after a median of 3 cases and 7 anastomoses.

Learning disability

Learning disability, clinically called specific learning disorder (DSM-5) or Developmental Learning Disorder (ICD-11), is a neurodevelopmental disorder causing persistent reading, writing, or math impairment despite adequate intelligence and instruction, affecting an estimated 5 to 15% of school-age children.

Leber congenital amaurosis

Leber congenital amaurosis (LCA, amaurosis congenita of Leber) is a group of inherited retinal dystrophies causing severe vision loss or blindness in the first year of life, usually autosomal recessive, involving over 20 genes including CEP290, GUCY2D, CRB1, and RPE65; RPE65-related disease is treatable with Luxturna gene therapy.

Leber hereditary optic neuropathy

Leber hereditary optic neuropathy, or Leber optic atrophy, is an inherited mitochondrial disease causing sudden, painless loss of central vision, typically in young adulthood, mainly in men.

Leber plus disease

Leber plus disease, also called LHON plus disease, is a rare inherited mitochondrial disease in which Leber hereditary optic neuropathy occurs alongside neurological or systemic abnormalities.

Lebrikizumab

Lebrikizumab (Ebglyss, lebrikizumab-lbkz) is an IgG4 monoclonal antibody interleukin-13 antagonist approved in 2024 for moderate-to-severe atopic dermatitis in patients 12 and older weighing at least 40 kg, dosed 250 mg every 2 weeks after loading.

Lecanemab

Lecanemab (Leqembi, BAN2401), an Eisai-Biogen humanized IgG1 antibody against amyloid-beta protofibrils for early Alzheimer's disease; FDA-approved 2023, slows CDR-SB decline 27% in CLARITY-AD, main risk ARIA.

Lecankitug (LZM012)

Lecankitug (莱康奇塔单抗, LZM012/XKH004) is a Chinese-developed IL-17A/F dual-target humanized monoclonal antibody by Livzon and Kanova, approved by NMPA in August 2026 for plaque psoriasis after beating secukinumab head-to-head.