Persius/hicric huggingface dataset:
Macula densa
In the kidney, the macula densa is an area of closely packed specialized cells lining the wall of the thick ascending limb of Henle (TALH) at the point of return of the nephron to the vascular pole of its parent glomerulus glomerular vascular pole.
The cells of the macula densa are sensitive to the ionic content and water volume of the fluid in the TALH, producing molecular signals that promote renin secretion by other cells of the juxtaglomerular apparatus. The release of renin is an essential component of the renin-angiotensin-aldosterone system (RAAS), which regulates blood pressure and volume.

# Histology
The cells of the macula densa cells are taller and have more prominent nuclei than surrounding cells of the thick ascending limb of Henle.
The close proximity and prominence of the nuclei cause this segment of the TALH wall to appear darker in microscopic preparations, hence the name macula densa.

# Function
A decrease in blood pressure results in a decreased concentration of sodium and chloride ions at the macula densa. (This is due to reduced filtration by the glomerulus: less filtrate is expelled into Bowman's space and the proximal convoluted tubule; the resulting fluid reaching the macula will have a lower sodium chloride concentration after the sodium chloride is removed along the thick ascending limb of Henle.)
In response, the macula densa cells release prostaglandins, which triggers granular juxtaglomerular cells lining the afferent arterioles to release renin into the bloodstream.  (The juxtoglomerular cells can also release renin independently of the macula densa, as they are also triggered by baroreceptors lining the arterioles, and release renin if a fall in blood pressure in the arterioles is detected.) Furthermore, activation of the sympathetic nervous system stimulates renin release through activation of beta-1 receptors.
Malacoplakia
Malakoplakia or Malacoplakia is a rare inflammatory condition which makes its presence known as a papule, plaque or ulceration that usually affects the genitourinary tract.:274 However, it may also be associated with other bodily organs. It was initially described in the early 1900s as soft yellowish plaques found on the mucosa of the urinary bladder. Microscopically it is characterized by the presence of foamy histiocytes with basophilic inclusions called Michaelis-Gutmann bodies.
It usually involves gram negative bacteria.

# Causes
Malakoplakia is thought to result from the insufficient killing of bacteria by macrophages. Therefore, the partially digested bacteria accumulate in macrophages and leads to a deposition of iron and calcium. The impairment of bactericidal activity manifests itself as the formation of an ulcer, plaque or papule.
Malakoplakia is associated with patients with a history of immunosuppression due to lymphoma, diabetes mellitus, renal transplantation, or because of long-term therapy with systemic corticosteroids.

# Treatment
Today, antibiotics are used for treatment of malakoplakia.

# Antimicrobial therapy
- Malacoplakia
- Preferred regimen (1): Bethanechol chloride AND Ciprofloxacin 400 mg IV q12h
- Preferred regimen (2): Bethanechol chloride AND TMP-SMX 2 mg/kg (TMP component IV q6h)
Malleability
Malleability is a mechanical property of matter, but is most commonly used in reference to metals and metalloids. A malleable metal is capable of being flattened into thin sheets without cracking by the processes of hammering or rolling. This property is important in metalworking, as materials that crack or break under pressure cannot be hammered or rolled. Malleable materials can be formed using stamping or pressing, whereas brittle metals and plastics must be molded.
Malleability occurs as a result of the specific type of bond found in metals (Main article: metallic bond). In metallic bonds, valence shell electrons are delocalized and shared between many atoms.  This is often referred to as the "sea of electrons" and is responsible for many properties of metal.  The delocalized electrons allow metal atoms to slide past one another without being subjected to strong repulsive forces that would cause other materials to shatter.
Gold is the most malleable metal, followed by aluminium. Many plastics, and amorphous solids such as Play-Doh are also malleable.
It also means changeable, as in "we are all malleable".
See also ductility and deformation.
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Mallinckrodt
Mallinckrodt Incorporated is a set of pharmaceutical, chemical, imaging, and respiratory equipment suppliers based in the St. Louis, Missouri area, which were recently purchased by Tyco Healthcare (Tyco International) and which have been proposed for further reorganization.  One division, Mallinckrodt Baker, was produced by merger with the chemical supplier founded by John Townshend Baker.
Mallinckrodt is the sole legal source for cocaine in the United States, which it receives from a Stepan Company plant in Maywood, New Jersey, which is the only firm in the U.S. licensed to import coca leaves.  Federal restrictions also bar the importation of drugs such as Esterom manufactured from cocaine, which therefore requires that they use this supplier.  Mallinckrodt is also one of the U.S. importers of opium from India.
The Mallinckrodt General Clinical Research Center received contributions from Edward Mallinckrodt, Jr., who headed the firm in the 1940s.
The legal decision Mallinckrodt, Inc. v. Medipart, Inc., 976 F.2d 700, 708 (Fed. Cir. 1992)) established a right of patent holders to limit the use of their products post-sale, and was cited in Arizona Cartridge Remanufacturers Association Inc. v. Lexmark International Inc., the decision that end-user licensing agreements on software boxes can be enforced against customers.
Malonic acid
Malonic acid (IUPAC systematic name: propanedioic acid) is a dicarboxylic acid with structure CH2(COOH)2. The ionised form of malonic acid, as well as its esters and salts, are known as malonates. For example, diethyl malonate is malonic acid's ethyl ester. The name originates from Latin malum, meaning apple.

# Biochemistry
The calcium salt of malonic acid occurs in high concentrations in beetroot.

# Organic synthesis
A classical preparation of malonic acid starts from acetic acid. This acid is chlorinated to chloroacetic acid. Sodium carbonate generates the sodium salt which is then reacted with sodium cyanide to the cyano acetic acid salt in a nucleophilic substitution. The nitrile group can be hydrolysed with sodium hydroxide to sodium malonate and acidification affords malonic acid.

# Organic reactions
In a well known reaction malonic acid condenses with urea to barbituric acid.  Malonic acid is frequently used as an enolate in Knoevenagel condensations or condensed with acetone to form Meldrum's acid.
Mantoux test
Synonyms and keywords: PPD, TB skin test, TST, tst

# Overview
The Mantoux tuberculin skin test (TST) is the standard method of determining whether a person is infected with Mycobacterium tuberculosis.  Reliable administration and reading of the TST requires standardization of procedures, training, supervision, and practice.

# Procedure
The TST is performed by injecting 0.1 ml of tuberculin purified protein derivative (PPD) into the inner surface of the forearm.  The injection should be made with a tuberculin syringe, with the needle bevel facing upward.  The TST is an intradermal injection.  When placed correctly, the injection should produce a pale elevation of the skin (a wheal) 6 to 10 mm in diameter.
The skin test reaction should be read between 48 and 72 hours after administration. A patient who does not return within 72 hours will need to be rescheduled for another skin test.
The reaction should be measured in millimeters of the induration (palpable, raised, hardened area or swelling). The reader should not measure erythema (redness). The diameter of the indurated area should be measured across the forearm (perpendicular to the long axis).

# Classification of Tuberculin Reaction
Skin test interpretation depends on two factors:
- Measurement in millimeters of the induration.
- Persons risk of being infected with TB and of progression to disease if infected.

# Contraindications
TST is contraindicated only for persons who have had a severe reaction (e.g., necrosis, blistering, anaphylactic shock, or ulcerations) to a previous TST. It is not contraindicated for any other persons, including infants, children, pregnant women, persons who are HIV-infected, or persons who have been vaccinated with BCG.

# False-Poisitve and False-Negative Reactions
In some persons who are infected with M. tuberculosis, the ability to react to tuberculin may wane over time. When given a TST years after infection, these persons may have a false-negative reaction. However, the TST may stimulate the immune system, causing a positive, or boosted reaction to subsequent tests. Giving a second TST after an initial negative TST reaction is called two-step testing.

# Two-step Testing
Two-step testing is useful for the initial skin testing of adults who are going to be retested periodically, such as health care workers or nursing home residents. This two-step approach can reduce the likelihood that a boosted reaction to a subsequent TST will be misinterpreted as a recent infection.
Medetomidine
Medetomidine (active form medetomidine hydrochloride) is a synthetic drug used as both a surgical anesthetic and analgesic. It is a crystalline white alpha-two adrenergic agonist that can be administered as an intravenous drug solution with sterile water. It is currently approved for dogs in the United States, and distributed by Pfizer Animal Health under the product name Domitor.
It is often used in combinations with opioids (butorphanol, buprenorphine etc) as premedication (before a general anaesthetic) in healthy cats and dogs.  It can be given by intramuscular injection (IM), subcutaneous injection (SI) or intravenous injection (II). When delivered intravenously, a significantly decreased dose is used.  Some authors suggest a sublingual route is also effective.
Following administration, marked peripheral vasoconstriction and bradycardia are noted.  Often the dosage of induction agents (i.e. propofol) may be drastically reduced, as may the volumes of anaesthetic gases (i.e. halothane, isoflurane, sevoflurane) used to maintain general anaesthesia.
It is sometimes used in combination with butorphanol and ketamine (given IM) to produce general anaesthesia for short periods in healthy but fractious felines that will not allow an intravenous induction agent to be given.
Medetomidine has also been used in combination with morphine (or methadone), lignocaine and ketamine in constant rate infusion analgesia in canines.  It is often used in so called microdoses for this analgesic effect.
It's effects can be reversed using atipamezole (distributed as Antisedan by Pfizer).

# See Also
- Veterinary anesthesia
Median plane

# Overview
The median plane is a sagittal plane which bisects the body through the umbilicus.
It is one of the lines used to define the right upper quadrant of the human abdomen.
The midsternal line can be interpreted as a segment of the median plane.
Ximelagatran

# Overview
Ximelagatran (Exanta or Exarta, H 376/95) is an anticoagulant that has been investigated extensively as a replacement for warfarin that would overcome the problematic dietary, drug interaction, and monitoring issues associated with warfarin therapy. In 2006, its manufacturer AstraZeneca announced that it would not attempt to market ximelagatran after reports of hepatotoxicity (liver damage) during trials, and to discontinue its distribution in countries where the drug had been approved.

# Method of action
Ximelagatran was the first member of the drug class of direct thrombin inhibitors that can be taken orally. It acts solely by inhibiting the actions of thrombin. It is taken orally twice daily, and rapidly absorbed by the small intestine. Ximelagatran is a prodrug, being converted in vivo to the active agent melagatran. This conversion takes place in the liver and many other tissues through dealkylation and dehydroxylation (replacing the ethyl and hydroxyl groups with hydrogen).

# Uses
Ximelagatran was expected to replace warfarin and sometimes aspirin and heparin in many therapeutic settings, including deep venous thrombosis, prevention of secondary venous thromboembolism and complications of atrial fibrillation such as stroke. The efficacy of ximelagatran for these indications had been well-documented (Eriksson et al 2003, Frances et al 2004, Schulman et al 2004).
An advantage, according to early reports by its manufacturer, was that it could be taken orally without any monitoring of its anticoagulant properties. This would have set it apart from warfarin and heparin, which require monitoring of the international normalized ratio (INR) and the partial thromboplastin time (PTT), respectively. A disadvantage recognised early was the absence of an antidote in case acute bleeding develops, while warfarin can be antagonised by vitamin K and heparin by protamine sulfate.

# Side-effects
Ximelagatran was generally well tolerated in the trial populations, but a small proportion (5-6%) developed elevated liver enzyme levels, which prompted the FDA to reject an initial application for approval in 2004. The further development was discontinued in 2006 after it turned out hepatic damage could develop in the period subsequent to withdrawal of the drug. According to AstraZeneca, a chemically different but pharmacologically similar substance, AZD0837, is undergoing testing for similar indications (AstraZeneca press release 2006).
Melanophilin
Melanophilin is a carrier protein which in humans is encoded by the MLPH gene. Several alternatively spliced transcript variants of this gene have been described, but the full-length nature of some of these variants has not been determined.

# Function
This gene encodes a member of the exophilin subfamily of Rab effector proteins. The protein forms a ternary complex with the small Ras-related GTPase Rab27A in its GTP-bound form and the motor protein myosin Va. A similar protein complex in mouse functions to tether pigment-producing organelles called melanosomes to the actin cytoskeleton in melanocytes, and is required for visible pigmentation in the hair and skin.
In melanocytic cells MLPH gene expression may be regulated by MITF.

# Clinical significance
A mutation in this gene results in Griscelli syndrome type 3, which is characterized by a silver-gray hair color and abnormal pigment distribution in the hair shaft.
Mutations in melanophilin cause the "dilute" coat color phenotype in dogs and cats. Variation in this gene appears to have been a target for recent natural selection in humans, and it has been hypothesized that this is due to a role in human pigmentation.
Mental model
A mental model is an explanation in someone's thought process for how something works in the real world.  It is a kind of internal symbol or representation of external reality, hypothesized to play a major role in cognition and decision-making. Once formed, mental models may replace carefully considered analysis as a means of conserving time and energy. A simple example is the mental model of a wild animal as dangerous: upon encountering a raccoon or a snake, one who holds this model will likely retreat from the animal as if by reflex. Retreat is the result of the application of the mental model, and would probably not be the immediate reaction of one whose mental model of wild animals was formed solely from experience with similar stuffed toy animals, or who had not yet formed any mental models about wild raccoons or snakes.
The term is believed to have been originated by Kenneth Craik in his 1943 book The Nature of Explanation.  After the early death of Craik in a bicycle accident, the idea was not elaborated on until much later. Before Craik, Georges-Henri Luquet had already developed this idea to some extent: in his seminal book Le dessin enfantin (Children's Drawings), published in 1927 by Alcan, Paris, he argued that children obviously construct internal models, a view that influenced, among others, Jean Piaget.
Two books, both titled Mental Models, appeared in 1983 .  One was by Philip Johnson-Laird, a psychology professor at Princeton University.  The other was a collection of articles edited by Dedre Gentner and Albert Stevens.  The first line of this book helps explain the idea further: "One function of this chapter is to belabor the obvious; people's views of the world, of themselves, of their own capabilities, and of the tasks that they are asked to perform, or topics they are asked to learn, depend heavily on the conceptualizations that they bring to the task." See Mental Models (Gentner-Stevens book).  Since then there has been much discussion and use of the idea in human computer interaction and usability by people such as Donald Norman and by Steve Krug in his book Don't Make Me Think. Walter Kintsch and Teun A. van Dijk, using the term situation model (in their book Strategies of Discourse Comprehension, 1983), showed the relevance of mental models for the production and comprehension of discourse.

# Researchers who study mental models
- Ruth Byrne
- Dedre Gentner
- Philip Johnson-Laird
- Stephen J. Payne, Internet Archive version
- Walter Kintsch
- Teun A. van Dijk
- Norbert M. Seel

# Software
- CONSIDEO MODELER
- STELLA / iThink
- VENSIM
Mesoridazine

# Overview
Mesoridazine (Serentil) is a piperidine neuroleptic drug belonging to the class of drugs called phenothiazines, used in the treatment of schizophrenia. It is a metabolite of thioridazine. The drug's name is derived from the methylsulfoxy and piperidine functional groups in its chemical structure.
It has central antiadrenergic, antidopaminergic, antiserotonergic and weak muscarinic anticholinergic effects.
Serious side effects include akathisia, tardive dyskinesia and the potentially fatal neuroleptic malignant syndrome.
Mesoridazine was withdrawn from the United States market in 2004 due to dangerous side effects, namely irregular heart beat and QT-prolongation of the electrocardiogram.
It currently appears to be unavailable worldwide.

# Chemistry
Mesoridazine (10--2-(methylsufinyl)phenothiazine) is synthesized by an analogous scheme to that seen already for thioridazine.
However, it is also synthesized by alkylating the acidic form of 2-methylthiophenothiazine -methylsulfonylphenothiazine- using 2-(2-chloroethyl)-1-methylpiperidine. 2-methylthiophenothiazine is initially acylated at the nitrogen atom using acetic anhydride, giving 10-acetyl-2-methylthiophenothiazine. The resulting acetyl derivative is further oxidized by hydrogen peroxide into 10-acetyl-2-methylsulfonylpenothiazine. Deacylation of this product in potassium carbonate methanol solution gives 2-methylsulfanylphenothiazine, which is alkylated by 2-(2-chlorethyl)-1-methylpiperidine in the presence of sodamide, affording the desired mesoridazine.
Metanauplius
Metanauplius is an early larval stage of some crustaceans such as krill. It follows the nauplius stage.
In sac-spawningTemplate:Fn krill, there is an intermediary phase called pseudometanauplius, a newly hatched form distinguished from older metanauplii by its extremely short abdomen. In some species, this form is not considered a separate developmental stage as it develops into a metanauplius without molting; in other species such as Nyctiphanes couchii, it can be separated from the metanauplius stage by the molt of a very thin cuticle soon after hatching.
Broadcast-spawning species of krill do not have a pseudometanauplius stage. They generally hatch in the nauplius 1 stage, but recently have been discovered to hatch sometimes as metanauplius or even as calyptopis stages.

# Footnotes
Methyl group

# Overview
In chemistry, a methyl group is a hydrophobic alkyl functional group derived from methane CH4). It has the formula -CH3 and is very often abbreviated as -Me in the structure of a molecule. This hydrocarbon unit can be found in many organic compounds. It is customarily written as H3C when on the left of a bond; for example, ethane is represented as H3C-CH3.
Methyl groups can be incorporated in organic compounds by an SN2 reaction on iodomethane, or by the reaction of methyl lithium or MeMgCl with a carbon atom that is substituted with a leaving group.

# Reactivity
The introduction of methyl groups as new substituents in a compound usually increases the lipophilicity of the compound and reduces its water solubility. It should improve the ease of absorption of the analogue into a biological membrane but will make its release from biological membranes into the aqueous media more difficult. The incorporation of a methyl group can have one of three general effects on the rate of metabolism of an analogue:
- an increased rate of metabolism due to oxidation of the methyl group
- an increase in the rate of metabolism due to demethylation by the transfer of the methyl group to another compound, or a reduction of the analogue.
Chemically, the reactivity of a methyl group depends partially on what it is attached to. For example, when a methyl group is part of an alkane, it is extremely unreactive and resists all but the strongest of acids, bases, oxidizing agents, and reducing agents. However, in the compound toluene, C6H5CH3, the methyl group is considerably more reactive due to the electron donating abilities of the ring.Electrophilic reagents are then able to attack the methyl group; for example, oxidation with permanganate converts the methyl group to carboxyl (-COOH), which produces benzoic acid.

# Methyl radical
The methyl radical is the substance CH3 on its own, with an unpaired electron. Though it readily dimerizes to ethane, it is stable enough (unlike atomic hydrogen) to be observed as a dilute gas. It can be produced by thermal decomposition of certain compounds, especially those with a -N=N- linkage, which lose the extremely stable dinitrogen molecule on heating.
Methysergide

# Overview
Methysergide (1-methyl-D-lysergic acid butanolamide or UML-491) is a prescription drug formerly used for prophylaxis of cluster headaches/migraine headaches, but is no longer recommended due to retroperitoneal/retropulmonary fibrosis.

# Medical uses
Methysergide is used to treat headaches such as migraine and other recurrent throbbing headaches. Methysergide is one of the most effective medications for the prevention of migraine, but not for the treatment of an acute attack.
It is also used in carcinoid syndrome to treat severe diarrhea. It may also be used in the treatment of serotonin syndrome.

# Side effects
It has a known side effect, retroperitoneal fibrosis, which is severe, although uncommon. Other severe but uncommon side effects include pleural fibrosis, and subendocardial fibrosis.
In addition, there is an increased risk of left-sided cardiac valve dysfunction.

# Pharmacology
Methysergide interacts with serotonin (5-HT) receptors. Its therapeutic effect in migraine prophylaxis has been associated with its antagonism at the 5-HT2B receptor.
Furthermore, it is an antagonist at the 5-HT2C receptor, while at the 5-HT1A receptor it serves as a partial agonist. It is known to have partial agonist effects on some of the other 5-HT receptors as well. Methysergide is metabolised into methylergometrine in humans, which is responsible for its psychedelic effects.

# History
Methysergide was approved by the U.S. Food and Drug Administration (FDA) in 1962.
Novartis withdrew it from the U.S. market after taking over Sandoz, but currently lists it as a product.

# Synthesis