Persius/hicric huggingface dataset:
Nucleic acid test

# Overview
A nucleic acid test, often called a "NAT", (or nucleic acid amplification test - "NAAT") is a molecular technique used to detect a virus or a bacterium.  These tests were developed to shorten the window period, a time between when a patient has been infected and when they show up as positive by antibody tests.
The term includes any test that directly detects the genetic material of the infecting organism or virus.  There are multiple methods that fall in this group, including:
- Methods based on the Polymerase chain reaction.  These tests use a primer to rapidly make copies of the genetic material.
A reverse transcriptase PCR (RT-PCR) is used for HIV and other RNA viruses.
Transcription mediated amplification uses a slightly different molecular method than PCR but has the same basic principle.
- A reverse transcriptase PCR (RT-PCR) is used for HIV and other RNA viruses.
- Transcription mediated amplification uses a slightly different molecular method than PCR but has the same basic principle.
- Branched DNA (quantiplex bDNA) tests use a molecule that links to the specific genetic material.
- Ligase chain reaction

# History
In 1999, new screening methods involving nucleic acid amplification and that protocol approved by FDA.
Nucleic acid Testing - Benefits:
- Detects low levels of viral RNA or DNA.
- Provides additional layer of safety to the blood supply because it allows the detection of infectious agents during their incubation period.
- Have the ability to detect viral mutants and occult infections.
- Highly sensitive and specific for viral nucleic acid.
Different Technology of Nucleic acid testing:
- Polymerase chain reaction (PCR)
- Branched DNA (bDNA)
- Transcription mediated amplification (TMA)
- Nucleic acid Sequence Based Amplification (NASBA)
NSAID nephropathy
- NSAID or Non-steroidal anti-inflammatory drug, are drugs with analgesic, antipyretic and anti-inflammatory effects - they reduce pain, fever and inflammation. The term "non-steroidal" is used to distinguish these drugs from steroids which have similar effects.
- Nephropathy or nephrosis refers to damage to or disease of the kidney.
Therefore NSAID Nephropathy is damage to the kidney as a result of taking NSAID drugs.

# Symptoms
- Acute renal failure secondary to renal hemodynamic changes
- Interstitial nephritis with or without proteinuria/nephrotic syndrome
- Hypertension

# Epidemiology
Epidemiology is the scientific study of factors affecting the health and illness of individuals and populations
- Very low, 1% to 3% of patients exposed experience one of the previously mentioned
- Delayed onset from initial use of NSAID
- Described with use in all types of NSAIDs
The number of people taking NSAIDs is very high, offsetting low rate per user to high rate per population.

# Pathophysiology
Pathophysiology is the study of the disturbance of normal mechanical, physical, and biochemical functions that a disease causes, or that which causes the disease
Inhibition of renal prostaglandin synthesis interferes with renal hemodynamics.
PGI2, PGE2 are responsible for:
- vasodilation in the arterioles and glomeruli
- decreased Na transport and natriuresis in the distal tubules
- Interferes with ADH action in the distal tubules
TXA2 shown to vasoconstrict glomeruli

## Clinical features: NSAID-Induced hemodynamic deterioration of Renal Function
- Prostaglandin Inhibition leads to further renal vasoconstriction
- Especially in the setting of already vasocontricted states such as CHF, nephrotic syndrome, cirrhosis, volume depletion, chronic kidney disease (CKD)
- 30% of patient with CKD on NSAIDS develop this syndrome
- Elderly also at increased risk mostly secondary to pharmacokinetics
- Fully reversible if caught early
- Rarely the sole cause of end-stage renal disease (ESRD)

## Clinical Features: NSAID Associated Tubulointerstitial nephritis
- Heavy Proteinuria/Nephrotic syndrome  83%
- Eosinophilia and Eosinophiluria uncommon  19%
- Focal tubulointerstitial infiltrates on biopsy
- Some + immunofluorescence for IgG, IgA, IgM and C3 in interstitial membranes
- Non-oliguric course typical
- Variable delayed onset
- May take weeks to many months to resolve, after stopping NSAID

## Clinical Features: NSAID associated Hypertension
- Usually only a modest increase in BP  an average increase of 6-8mmHg of MAP in patient on NSAIDs
- NSAIDs mitigate effects of B-blockers and diuretics
- CCB less susceptible to effects of NSAIDs
- Elderly, Blacks, low renin hypertension most susceptible

## Clinical Oddballs
- Minimal change disease/Nephrotic syndrome
- Hyperkalemia  NSAIDs anecdotally used to treat Bartter syndrome.

# Treatment
- Withdraw NSAIDs
- Avoid Nephrotoxic meds
- +/- Steroids with NSAID associated tubulointerstitial nephritis
Nasolacrimal duct

# Overview
The nasolacrimal duct carries tears from the lacrimal sac into the nasal cavity. Excess tears flow through nasolacrimal duct which opens in the nose. This is the reason the nose starts to run when a person is crying, or why you can sometimes taste eye drops.
Like the lacrimal sac, the duct is lined by stratified columnar epithelium containing mucus-secreting goblet cells, and is surrounded by connective tissue.
Obstruction of the nasolacrimal duct leads to the excess overflow of tears called epiphora. Persons with dry eye conditions can be fitted with punctal plugs that seal the ducts to limit the amount of fluid drainage and retain moisture.
The canal containing the nasolacrimal duct is called the nasolacrimal canal.

# Additional images
- Roof, floor, and lateral wall of left nasal cavity.
Natural reservoir
Natural reservoir or nidus, refers to the long-term host of the pathogen of an infectious disease. It is often the case that hosts do not get the disease carried by the pathogen or it is asymptomatic and non-lethal. Once discovered, natural reservoirs elucidate the complete life cycle of infectious diseases, providing effective prevention and control. Examples of natural reservoirs are:
- Field mice, for hantaviruses and Lassa fever
- Marmots, black rats, prairie dogs, chipmunks and squirrels for bubonic plague
- Armadillos and opossums for Chagas disease
- Ticks for babesiosis and Rocky Mountain spotted fever
- Ground squirrels, porcupines, and chipmunks for Colorado tick fever
- Mosquitoes for filariasis and malaria
- Snails for schistosomiasis and swimmer's itch
- Pigs for cestode worm infections
- Raccoons, skunks, foxes and bats for rabies
- Shellfish for cholera
- Fowl (ducks and geese) for avian flu
Some diseases have no non-human reservoir: poliomyelitis and smallpox are prominent examples.
The concept of natural reservoir could also be extended to asymptomatic human bearers of the infecting agent, exemplified by the famous case of Typhoid Mary.
The natural reservoir of some diseases remain unknown. This is the case of the Ebola disease, which is caused by a virus.
Negative feedback
Negative feedback feeds part of a system's output, inverted, into the system's input; generally with the result that fluctuations are attenuated. Many real-world systems have one or several points around which the system gravitates. In response to a perturbation, a negative feedback system with such point(s) will tend to re-establish equilibrium.
In many physical and biological systems, qualitatively different influences can oppose each other. For example, in biochemistry, one set of chemicals drives the system in a given direction, whereas another set of chemicals drives it in an opposing direction. If one, or both of these opposing influences are non-linear, an equilibrium point(s) results.
In Biology, this process (generally biochemical) is often referred to as Homeostasis.

# Examples

## Biology
Some biological systems exhibit negative feedback such as the baroreflex in blood pressure regulation and erythropoiesis. Many biological process (e.g., in the human anatomy) use negative feedback. Examples of this are numerous, from the regulating of body temperature, to the regulating of blood glucose levels. The disruption of negative feedback can lead to undesirable results: in the case of blood glucose levels, if negative feedback fails, the glucose levels in the blood may begin to rise dramatically, thus resulting in diabetes.

## Social sciences
A meta-analysis of the delivery of negative feedback concluded "negative feedback seemed to be less demotivating when (a) the feedback statement included instructional details on how to improve, (b) criterion-based standards were used to provide feedback, and (c) feedback was delivered in-person"
Nelson's syndrome
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# Overview
Nelson's syndrome is the rapid enlargement of a pituitary adenoma that occurs after the removal of both adrenal glands.

# Historical Perspective

# Classification

# Pathophysiology
Removal of both adrenal glands, or bilateral adrenalectomy, is an operation for Cushing's Disease. Removal of both adrenals eliminates production of cortisol, and the lack of cortisol's negative feedback can allow any preexisting pituitary adenoma to grow unchecked. Continued growth can cause mass effects due to physical compression of brain tissue, along with increased production of adrenocorticotrophic hormone (ACTH) and melanocyte stimulating hormone (MSH).

# Causes

# Differentiating Nelson's syndrome from Other Diseases

# Epidemiology and Demographics
Nelson's syndrome is rare because bilateral adrenalectomy is now only used in extreme circumstances.

# Risk Factors

# Screening

# Natural History, Complications, and Prognosis

## Natural History

## Complications

## Prognosis

# Diagnosis

## Diagnostic Criteria

## History and Symptoms
- Muscle weakness

## Physical Examination
- Skin hyperpigmentation due to excess MSH.

## Laboratory Findings

## Imaging Findings

## Other Diagnostic Studies

# Treatment

## Medical Therapy

## Surgery

## Prevention
Nessler's reagent

# Overview
Neler's reagent is a reagent named after Julius Neler and is used to detect small amounts of ammonia. It is a 0.09 mol/L solution of potassium tetraiodomercurate(II) (K2) in 2.5 mol/L potassium hydroxide. A yellow coloration indicates the presence of ammonia: at higher concentrations, a brown precipitate may form. The sensitivity as a spot test is about 0.3 g NH3 in 2 L.

# Toxicity
It is toxic if swallowed, inhaled or absorbed through the skin. It presents a neurological hazard and may act as a carcinogen and be a reproductive hazard. It is corrosive and causes burns.

# Other names
Neler's solution, mercuric potassium iodide, mercury(II) potassium iodide, Channing's solution, potassium mercuric iodide, potassium tetraiodomercurate(II)

# Preparation
Neler's reagent is generally prepared from potassium iodide and mercury(II) chloride. Hot concentrated solution of mercury(II) chloride is added to concentrated solution of potassium iodide, until the precipitate of mercury(II) iodide stops dissolving. The liquid is filtered, and potassium hydroxide and a further bit of mercury(II) chloride solution are added. The resulting solution is then cooled and diluted to required concentration. 

# Reference
- Template:VogelQualitative
Neuropharmacology
Neuropharmacology is concerned with drug-induced changes in the functioning of cells in the nervous system..  
Within the discipline of neuropharmacology there are two branches, behavioral and molecular.
Neuropharmacology is concerned with the study of the neurochemical interactions of neuropeptides, neurohormones, neuromodulators, enzymes, secondary messenger systems of the central nervous system, co-transporters, ion channels, receptor proteins, and more.
Newcastle disease

# Overview
Newcastle disease is a highly contagious zoonotic bird disease affecting many domestic and wild avian species. Its effects are most notable in domestic poultry due to their high susceptibility and the potential for severe impacts of an epidemic on the poultry industries. It is endemic to many countries.
Newcastle Disease was discovered in the East Indies in 1926, but it is named after Newcastle-upon-Tyne, England, where it was rediscovered a year later in 1927.
The causal agent, Newcastle disease virus (NDV), is a negative-sense single-stranded RNA virus. Transmission occurs by exposure to faecal and other excretions from infected birds, and through contact with contaminated feed, water, equipment and clothing.
Exposure of humans to infected birds (for example in poultry processing plants) can cause mild conjunctivitis and influenza-like symptoms, but NDV otherwise poses no hazard to human health. Interest in the use of NDV as an anticancer agent has arisen from the ability of NDV to selectively kill human tumour cells with limited toxicity to normal cells.
Signs of infection with NDV vary greatly depending on factors such as the strain of virus and the health, age and species of the host. They can include respiratory signs (gasping, coughing), nervous signs (depression, inappetence, drooping wings, paralysis), swelling of the eyes and neck, diarrhoea, misshapen, rough- or thin-shelled eggs and reduced egg production.
NDV strains can be categorised as velogenic (highly virulent), mesogenic (intermediate virulence) or lentogenic (nonvirulent). Velogenic strains produce severe nervous and respiratory signs, spread rapidly and cause up to 90% mortality. Mesogenic strains cause coughing, affect egg quality and production and result in up to 10% mortality. Lentogenic strains produce mild signs with negligible mortality.
No treatment for NDV exists, but the use of prophylactic vaccines and sanitary measures reduces the likelihood of outbreaks.

## Newcastle disease variant
In 1999, promising results were found using the Newcastle virus in cancer patients. In 2006 researchers from the Hebrew University have succeeded in isolating a variant of the Newcastle Disease Virus (NDV-HUJ), in order to specifically target cancer cells . NDV-HUJ is a natural variant of NDV Virus and is also an attenuated variant (e.g., weakened virus), it innately preferentially targets and replicates in certain types of tumor cells (brain and lung), leaving normal cells almost unaffected. The researchers tested the new Viro-therapy on 14 Glioblastoma multiforme patients and achieved promising results for the first time.
Niacin/lovastatin
Synonyms / Brand Names: ADVICOR

# Overview
Niacin/lovastatin (trade names Advicor, Mevacor) is a drug combination used for the treatment of dyslipidemia. It is a combination of the vitamin niacin and the statin drug lovastatin. The combination preparation is marketed by Abbott Laboratories
It was approved by the FDA on December 17, 2001.

# Category
Combination drugs;Hypolipidemic agents;Cardiovascular Drugs;

# FDA Package Insert
Indications and Usage

# Mechanism of Action

## Niacin
The mechanism by which niacin alters lipid profiles is not completely understood and may involve several actions, including partial inhibition of release of free fatty acids from adipose tissue, and increased lipoprotein lipase activity (which may increase the rate of chylomicron triglyceride removal from plasma). Niacin decreases the rate of hepatic synthesis of VLDL-C and LDL-C, and does not appear to affect fecal excretion of fats, sterols, or bile acids.

## Lovastatin
Lovastatin is a specific inhibitor of 3-hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase, the enzyme that catalyzes the conversion of HMG-CoA to mevalonate. The conversion of HMG-CoA to mevalonate is an early step in the biosynthetic pathway for cholesterol. Lovastatin is a prodrug and has little, if any, activity until hydrolyzed to its active beta-hydroxyacid form, lovastatin acid. The mechanism of the LDL-lowering effect of lovastatin may involve both reduction of VLDL-C concentration and induction of the LDL receptor, leading to reduced production and/or increased catabolism of LDL-C.

# Interaction with Alcohol
ADVICOR should be used with caution in patients who consume substantial quantities of alcohol and/or have a past history of liver disease.Patients should be advised to avoid  ingestion of alcohol, hot beverages and spicy foods around the time of ADVICOR administration.
Niacin receptor 1
Hydroxycarboxylic acid receptor 2 (HCA2), also known as niacin receptor 1 (NIACR1) and GPR109A, is a protein which in humans is encoded by the HCAR2 gene.

# Function
HCA2 is a high-affinity Gi/Go-coupled G protein-coupled receptor (GPCR) for nicotinic acid (niacin), and is a member of the nicotinic acid receptor family of GPCRs. HCA2 activation inhibits lipolytic and atherogenic activity (i.e., it inhibits the breakdown of fats and the development of atherosclerosis), induces vasodilation (i.e., the dilation of blood vessels), and is responsible for niacin-induced flushing.

## 5-oxo-ETE
The mouse ortholog of HCA2, Niacr1, has been proposed to mediate the ability of 5-oxo-ETE, a member of the 5-HETE family of eicosanoids, to stimulate the production of steroidogenic acute regulatory protein mRNA, Steroidogenic acute regulatory protein, and thereby progesterone in mouse cultured MA-10 Leydig cells.  Human tissues respond to 5-oxo-ETE and other 5-HETE family members though the OXER1 G protein-coupled receptor. The roles, if any, of Niacr1 in the response of leydig cells to other 5-HETE family members, of Niacr1 in the response of other mouse cells to 5-HETE family members, and the role of HCA2 in the response of human tissues to 5-HETE family members has not been determined.

# Clinical significance
HCA2 is an important biomolecular target of niacin which is a widely prescribed drug for the treatment of dyslipidemia and to increase HDL cholesterol but whose therapeutic use is limited by flushing. In HCA2 knockout mice, the effects of niacin on both lipids and flushing is eliminated.  Furthermore, in arrestin beta 1 knockout mice, niacin's effect on flushing is greatly reduced while the lipid modifying effects are maintained. At high doses, niacin produces marked anti-inflammatory effects in a variety of tissues  including the brain, gastrointestinal tract, skin, and vascular tissue  through activation of HCA2. Niacin has also been shown to attenuate neuroinflammation in part through NIACR1 binding; consequently, HCA2 has been identified as a potential therapeutic target for treating neuroimmune disorders such as multiple sclerosis and Parkinson's disease.
The precise mechanism of action of niacin therapeutic effects has not been fully elucidated, but appears to work in part through activation of HCA2 which reduces the levels of intracellular cAMP thereby inhibiting lipolysis in adipocytes.  In contrast, the flushing effect is due to HCA2 activation of ERK 1/2 MAP kinase mediated by arrestin beta 1. Activation of MAP kinase in turn causes release of prostaglandin D2 from Langerhans cells in the skin.

# Ligands
Full agonists of HCA2 include:
- Niacin (also known as vitamin B3 and nicotinic acid)
- Butyric acid and butyrate
Niacin receptor 2
Hydroxycarboxylic acid receptor 3 (HCA3), also known as niacin receptor 2 (NIACR2) and GPR109B, is a protein which in humans is encoded by the HCAR3 gene.

# Function
HCA3 is a low affinity receptor for nicotinic acid (niacin) and is a member of the hydroxycarboxylic acid family of G protein-coupled receptors (the other identified member being HCA2).
HCA3 is a Gi/Go-coupled G protein-coupled receptor with low affinity for nicotinic acid.
Nigella damascena
Nigella damascena (Love-in-a-mist) is an annual garden flowering plant, belonging to the buttercup family (Ranunculaceae).
It is native to southern Europe (but adventive in more northern countries of Europe), north Africa and southwest Asia. It is also commonly grown in gardens in North America. It is found on neglected, damp patches of land.
The plant's common name comes from the flower being nestled in a ring of multifid, lacy bracts. It's also sometimes called Devil in the Bush.
It grows to 20-50 cm tall, with pinnately divided, thread-like,  alternate leaves.
The flowers are white, pink, pale blue or pale purple, with 5-10 sepals. The actual petals are located at the base of the stamens and are minute and clawed. The sepals are the only colored part of the perianth. The 4-5 carpels of the compound pistil have each an erect style. The flowers blossom in May and June.
The fruit is a large and inflated capsule, growing from a compound ovary, and is  composed of several united follicles, each containing numerous seeds. This is rather exceptional for a member of the buttercup family. The capsule becomes brown in late summer.
They are much used in dried flower bouquets.
There are several cultivars available with flowers in shades of pink and purple, including 'Albion', 'Blue Midget', 'Cambridge Blue', 'Miss Jekyll',  'Mulberry Rose', 'Oxford Blue' and 'Persian Jewels'.

# Related Species
The related Nigella sativa (and not N. damascena) is the source of the spice variously known as Nigella, Kalonji or Black Cumin.
Nitrosyl chloride
Nitrosyl chloride is the chemical compound NOCl.  It is a yellow gas that is most commonly encountered as a decomposition product of aqua regia, a mixture of hydrochloric acid and nitric acid. The related nitrosyl halides nitrosyl fluoride, NOF, and nitrosyl bromide, NOBr, are also known.

# Structure and synthesis
Although its formula is written NOCl, the structure is better represented ONCl.  A double bond exists between N and O (distance = 1.16 A) and a single bond between N and Cl (distance = 1.69 A).  The O-N-Cl angle is 113.
NOCl can be prepared by the direct combination of chlorine and nitric oxide.   Alternatively, nitrosylsulfuric acid and HCl also affords the compound:
It also arises from the combination of hydrochloric and nitric acids according to the following reaction:
Although this mixture was used for dissolving gold for a long time the first description of the gas was done by Edmund Davy in 1831.

# Reactions
- NOCl reacts with halide acceptors to give the nitrosyl cation, +.  This species is available as NOBF4.
- NOCl reacts with water to release HCl.
- Heating NOCl above 100 C gives back Cl2 and NO.
- In organic synthesis, NOCl is often employed.  It adds to alkenes to afford -chloro oximes.

# Safety
NOCl is toxic and irritating to the lungs.
Nodular fasciitis
Synonyms and keywords: Nodular pseudosarcomatous fasciits; subcutaneous pseudosarcomatous fibromatosis

# Overview
Nodular fasciitis, also known as Nodular pseudosarcomatous fasciits and Subcutaneous pseudosarcomatous fibromatosis:992, is a benign lesion most commonly found in the superficial fascia. It is most common in young persons on the upper extremities and trunk.  Commonly mistaken for a sarcoma.

# Pathophysiology

## Histology
- Histologically vast array of patterns.
- Short S-shaped fascicles, inflammation, accelerated mitotic index with normal mitoses.
- Essentially spindle cell proliferation.
- Stroma is rich in collagen and/or myxoid ground substance.

# Natural History and Prognosis
Similar to a dermatofibroma, it is believed to be a reparative process secondary to trauma, which is frequently not remembered. It evolves rapidly, but is usually less than 3 cm in diameter.  There is an extremely low incidence of recurrence after resection.