Human health and medicine

Nkosi Johnson

Nkosi Johnson (Xolani Nkosi, 1989-2001), South African child born with HIV and AIDS activist; foster son of Gail Johnson, founder with him of Nkosi's Haven, famed for his 2000 Durban AIDS conference speech.

NKX6-2-related autosomal recessive hypomyelinating leukodystrophy

NKX6-2-related autosomal recessive hypomyelinating leukodystrophy, also known as spastic ataxia 8 (SPAX8), is a rare genetic white-matter disease caused by NKX6-2 variants, ranging from severe infantile spasticity to later-onset ataxia.

NLRP12-associated hereditary periodic fever syndrome

NLRP12-associated hereditary periodic fever syndrome, also called FCAS2 or NAPS12 (OMIM 611762), is a rare autosomal dominant autoinflammatory disease with cold-triggered recurrent fever, urticaria-like rash and arthralgia caused by NLRP12 gene variants, most often p.F402L.

NLST trial

The National Lung Screening Trial (NLST) was an American trial of 53,454 heavy smokers showing low-dose CT screening lowered lung cancer deaths 15 to 20 percent versus chest X-ray.

NMDA receptor antagonist

NMDA receptor antagonists are drugs blocking the NMDA glutamate receptor, via competitive, channel-blocker (ketamine, memantine, MK-801), or allosteric (ifenprodil) mechanisms; used in anesthesia, depression (esketamine), and pain, limited by psychotomimetic and neurotoxic side effects.

NMESWAL trial

NMESWAL trial (NCT07445204), Istanbul Arel University randomized controlled trial comparing sensory, motor, and modified combined VitalStim NMES protocols with conventional swallowing therapy for acute stroke-related dysphagia and hemiparesis.

NNZ-2591

NNZ-2591 (ercanetide), also called cyclo-L-glycyl-L-2-allylproline, is Neuren Pharmaceuticals' oral IGF-1 metabolite analog in Phase 3 (Koala trial) for Phelan-McDermid syndrome and in development for Pitt Hopkins, Angelman, HIE, and SYNGAP1-related disorder.

No Nut November

No Nut November (NNN) is an annual internet challenge, coined on Urban Dictionary in 2011 by bicboi6969696969, in which participants abstain from masturbation and ejaculation for November; it went viral in 2017 and has contested health claims.

No pain, no gain

No pain, no gain: English proverb meaning suffering is needed for progress, dating to the 1500s and John Ray's 1670 collection, popularized by Jane Fonda's 1982 aerobics videos, now questioned by exercise science showing soreness is unnecessary for strength gains.

No trade name

No trade name is the FDA's trade-name entry for Adenovirus Type 4 and Type 7 Vaccine, Live, Oral (BLA 125296), a live oral adenovirus vaccine approved March 16, 2011, used only by the U.S. military.

Nobel Prize in Physiology or Medicine

Nobel Prize in Physiology or Medicine, annual award under Alfred Nobel's 1895 will, given since 1901 by the Nobel Assembly at Karolinska Institutet for major life-science discoveries; 2025 went to Brunkow, Ramsdell, and Sakaguchi, 2026 to Deisseroth, Hegemann, and Nagel for optogenetics.

Nobel Prize in Physiology or Medicine for neuroscience research

Nobel Prizes in Physiology or Medicine have honored neuroscience since 1906, when Golgi and Cajal shared the first, through at least 17 prizes and 40 laureates to 2021.

Nocardiosis

Nocardiosis, infection by soil-dwelling Nocardia bacteria (including N. farcinica, N. brasiliensis), affects lungs, brain, and skin, mainly in immunocompromised people, treated with months of antibiotics such as trimethoprim-sulfamethoxazole.

NOCARH syndrome

NOCARH syndrome, first described in 2019, is a rare autoinflammatory disease caused by CDC42 gene mutations, marked by neonatal low blood counts, painful rash, and life-threatening HLH episodes.

Nociceptor

A nociceptor, also called a pain receptor, is a sensory neuron that responds to noxious, tissue-damaging stimuli, triggering pain signals in the spinal cord and brain.

Nocturnal and diurnal enuresis

Nocturnal and diurnal enuresis (ICD-11 6C00.2) is repeated involuntary or intentional urination into bed or clothes both during sleep and waking hours after age 5; also called combined enuresis, treated with alarms or desmopressin.

Nocturnal emission

Nocturnal emission (wet dream, nightfall): involuntary ejaculation during sleep, a normal part of male puberty, typically first occurring at 13-14 years with 70-90% prevalence; occurs with or without erotic dreams and has clinical uses in anejaculation.

Nocturnal enuresis

Nocturnal enuresis, or bedwetting, is involuntary urination during sleep in children aged 5 or older; primary or secondary, monosymptomatic or not, treated with alarm or desmopressin.

Nocturnal penile tumescence

Nocturnal penile tumescence (sleep-related erection): spontaneous REM-sleep erections in healthy males, measured clinically with the RigiScan NPTR test to distinguish psychogenic from organic erectile dysfunction, mainly in selected and medico-legal cases.

Nodal marginal zone lymphoma

Nodal marginal zone B-cell lymphoma (NMZL) is a rare indolent B-cell lymphoma of the lymph nodes, one of three marginal zone lymphoma subtypes, distinguished from splenic and MALT lymphoma by PTPRD mutations and purely nodal dissemination.

Sep 29, 2026

Nodal radiotherapy

Nodal radiotherapy is the irradiation of regional lymph nodes in cancers such as lymphoma, prostate, and breast, ranging from elective whole-basin coverage to stereotactic treatment of single nodes.

Nodal T-follicular helper cell lymphoma, follicular type

Nodal T-follicular helper cell lymphoma, follicular type (nTFHL-F), formerly follicular T-cell lymphoma, is a rare nodal T-cell lymphoma of TFH-cell origin with follicular growth, lacking AITL-type vascular changes.

Nodular acne

Nodular acne, also called cystic or nodulocystic acne (ICD-11 ED80.3), is severe inflammatory acne with firm, painful nodules deep in the skin. Systemic isotretinoin is the strongly recommended treatment; untreated nodules scar.

Nodular cutaneous amyloidosis

Nodular cutaneous amyloidosis (PLCNA), the rarest form of primary cutaneous amyloidosis: AL light-chain amyloid from local plasma cells forms waxy 5–20 mm nodules on acral sites, with about 7–10% risk of systemic progression.

Nodular fasciitis

Nodular fasciitis, also called pseudosarcomatous fasciitis, is a benign, self-limited soft tissue tumor that grows rapidly over weeks, mimics sarcoma, and rarely recurs after simple excision.

Nodular lichen myxedematosus

Nodular lichen myxedematosus (atypical tuberous myxedema of Jadassohn-Dosseker), ORPHA:90393, is a rare localized cutaneous mucinosis with skin-coloured mucinous nodules on limbs and trunk, without monoclonal gammopathy or thyroid disease.

Nodular lymphocyte predominant Hodgkin lymphoma

Nodular lymphocyte predominant Hodgkin lymphoma (NLPHL, NLPBL) is a rare, indolent Hodgkin lymphoma subtype with CD20-positive LP cells, early-stage presentation, and risk of DLBCL transformation.

Nodular neuronal heterotopia

Nodular neuronal heterotopia (periventricular nodular heterotopia, PNH) is a rare malformation of cortical development in which neurons fail to migrate, forming gray-matter nodules along the ventricles; causes include FLNA and ARFGEF2 mutations, with epilepsy in 80-90% of patients.

Nodular non-suppurative panniculitis

Nodular non-suppurative panniculitis, also called Weber-Christian disease or idiopathic lobular panniculitis, is a rare disorder with recurrent fever and subcutaneous fat nodules, first described by Pfeifer in 1892 and now largely reclassified into specific panniculitides.