Persius/hicric huggingface dataset:
PallisterKillian syndrome

# Overview
PallisterKillian syndrome (also tetrasomy 12p mosaicism or Pallister mosaic aneuploidy syndrome) is an extremely rare genetic disorder occurring in humans. Pallister-Killian occurs due to the presence of the anomalous extra isochromosome 12p, the short arm of the twelfth chromosome. This leads to the development of tetrasomy 12p. Because not all cells have the extra isochromosome, Pallister-Killian is a mosaic condition.
It was first described by Philip Pallister in 1977 and further researched by Maria Teschler-Nicola and Wolfgang Killian in 1981.

# Characteristics
Characteristics include varying degrees of developmental disability, epilepsy, hypotonia, and both hypopigmentation and hyperpigmentation. Patients also exhibit a distinctive facial structure, characterized by high foreheads, sparse hair on the temple, a wide space between the eyes, epicanthal folds, and a flat nose. Vision and hearing impairments may occur. Patients may also exhibit congenital heart defects, gastroesophageal reflux, cataracts, and supernumerary nipples. Diaphragm problems seen in newborns can lead to death shortly after birth.
As patients pass into adolescence, the syndrome is characterized by a coarse and flat face, macroglossia prognathia, inverted lower lip, and psychomotor retardation with muscular hypertonia and contractures.

# Causes
Pallister-Killian does not appear to be hereditary. Some research has suggested that the presence of the extra chromosome may be linked to premeiotic mitotic errors, both maternally and paternally. Several theories regarding the mechanism of this formation have been introduced.

# Diagnosis
The isochromosome can be primarily detected in samples of skin fibroblasts, as well as in chorionic villus and amniotic fluid cell samples. Very rarely, it can also be detected in blood lymphocytes. It is also possible to detect the isochromosome in circulating lymphocytes, as well as other amniotic and placental samples. There is no strict limit as to where the isochromosome can be found. However, it is often unlikely that these samples will be tested when the blood karyotype is normal.
Using an ultrasound, Pallister-Killian may be diagnosed through observation of hypertelorism, broad neck, shorts limbs, abnormal hands or feet, diaphragmatic hernia, and hydramnios. Once born, a child may be diagnosed by observation of the syndrome's distinct facial features.
Paramethoxymethamphetamine
Para-methoxy-methamphetamine, also called 4-methoxymethamphetamine, Methyl-MA or PMMA, is a stimulant drug related to PMA and methamphetamine.
PMMA reputedly produces similar effects to PMA, but is apparently slightly more similar to MDMA in effects  and has slightly less tendency to produce severe hyperthermia, at least at low doses. At higher doses however the side effects and danger of death are just as severe as those of PMA itself, and PMMA should be considered a dangerous drug similar to its parent compound.
PMMA is a lesser-known psychedelic drug.  It is the 4-methoxy  analog of Methamphetamine (crystal meth). PMMA was probably first synthesized by Alexander Shulgin. In his book PIHKAL (Phenethylamines I Have Known and Loved), the minimum dosage is listed as 100 mg, and the duration unknown. Shulgin reported that Methyl-MA produces an increase in blood pressure and in heart rate, but causes no psychoactive effects, however user reports following the subsequent appearance of this drug on the illicit market as an analogue of "Ecstasy" (MDMA) suggest that PMMA does produce some empathogenic effects. Very little data exists about the pharmacological properties, metabolism, and toxicity of PMMA, and given the known toxicity of the related compound PMA it is likely to have considerable potential to cause harmful side effects or overdose which can be fatal.
Pathology (disambiguation)
The term pathology most often refers to the study of disease: its causes, processes, development, consequences, and anatomic and functional manifestations. A field of medicine specializing in the categorization of medical diseases (as studied in the laboratory) is called Pathology. Physicians who specialize in medical laboratory pathology are called Pathologists.
Any abnormal process can be termed to be pathologic. Some examples of the application of the term are listed.

# Health Pathologies
- Anatomic pathology refers to the study of abnormal structures in medicine. The term encompasses gross (visible to the naked eye), microscopic (cellular), and molecular structural abnormalities. Surgical pathology, autopsy pathology, and forensic pathology refer to specific settings in which analysis of structural abnormalities is undertaken.
- Speech pathology is an area of rehabilitative medicine concerned with the treatment of speech or swallowing impediments.

# Psychological / Behavioural Pathologies
Psychopathology is a term which is used synonymously with mental illness.
Pathological can be used to describe a person's actions in such a way as to credit the action to a disease process.
- Pathological purchasing
- Pathological consumption
- Pathological narcissism
- Pathological liar
- Pathological gambling
- Pathological jealousy

# Other Scientific Usage
- phytopathology is the study of abnormalities in plant structure and function.
Pathological is also used in mathematics, physics, and statistics to describe an exceptionally atypical example or set of data:
- pathological (mathematics)
- pathological science

# Media
- Pathology (film), an upcoming film starring Milo Ventimiglia and Alyssa Milano.
Perfusion weighted imaging

# MR Perfusion
Perfusion weighted imaging or MR perfusion is a term used to denote a variety of MRI techniques able to give insights into the perfusion of tissues by blood.

## Techniques
There are three techniques in wide use to derive one or more perfusion values.
- Dynamic susceptibility contrast imaging (DSC)
- Dynamic contrast enhanced imaging (DCE)
- Arterial spin labelled imaging (ASL)

## Derived values
- Time to peak (TTP)
- Mean transit time (MTT)
- Cerebral blood volume (CBV)
- Cerebral blood flow (CBF)
- Negative enhancement integral (NEI)
- K-trans
The main role of perfusion imaging is in evaluation of ischemic conditions (e.g. acute cerebral infarction to determine ischemic penumbra, moya-moya disease to identify vascular reserve) and neoplasms (e.g. identify highest grade component of diffuse astrocytomas, help distinguish glioblastomas form cerebral metastases).
Pica (patient information)
For the WikiDoc page for this topic, click here

# Overview
Pica is a pattern of eating non-food materials (such as dirt or paper).

# What are the symptoms of Pica?
- Children and adults with pica may eat:
- Animal feces
- Clay
- Dirt
- Hairballs
- Ice
- Paint
- Sand
- This pattern of eating should last at least 1 month to fit the diagnosis of pica.

# What causes Pica?
- Pica is seen more in young children than adults. Between 10 and 32% of children ages 1 - 6 have these behaviors.
- Pica can occur during pregnancy.
- In some cases, conditions due to a lack of certain nutrients, such as iron deficiency anemia and zinc deficiency, may trigger the unusual cravings.
- Pica may also occur in adults who crave a certain texture in their mouth.

# When to seek urgent medical care?
Call your health care provider if you notice that a child (or adult) often eats non-food materials.

# Diagnosis
- There is no single test that confirms pica. However, because pica can occur in people who have lower than normal nutrient levels and poor nutrition (malnutrition), the health care provider should test blood levels of iron and zinc.
- Blood tests can also be done to test for anemia.
- Lead levels should always be checked in children who may have eaten paint or objects covered in lead-paint dust to screen for lead poisoning.
- The health care provider should test for infection if the person has been eating contaminated soil or animal waste.

# Treatment options
- Treatment should first address any missing nutrients or other medical problems, such as lead exposure.
- Treatment involves behavioral, environmental, and family educational approaches.
- Other successful treatments include associating the pica behavior with bad consequences or punishment (mild aversion therapy) followed by positive reinforcement for eating the right foods.
- Medications may help reduce the abnormal eating behavior, if pica occurs as part of a developmental disorder such as mental retardation.

# Where to find medical care for Pica?
Directions to Hospitals Treating Pica

# What to expect (Outlook/Prognosis)?
- Treatment success varies. In many cases, the disorder lasts several months, then disappears on its own.
- In some cases, it may continue into the teen years or adulthood, especially when it occurs with developmental disorders.

# Possible complications
- Bezoar (a mass of undigestible material trapped inside the body, usually in the stomach)
- Infection
- Intestinal obstruction
- Lead poisoning
- Malnutrition

# Prevention
There is no specific prevention. Getting enough nutrition may help.

# Source
Retinal pigment epithelium

# Overview
The retinal pigment epithelium is the pigmented cell layer just outside the neurosensory retina that nourishes retinal visual cells, and is firmly attached to the underlying choroid and overlying retinal visual cells.

# Appearance
The RPE is composed of a single layer of hexagonal cells that are densely packed with pigment granules.
When viewed from the outer surface, these cells are smooth and hexagonal in shape. When seen in section, each cell consists of an outer non-pigmented part containing a large oval nucleus and an inner pigmented portion which extends as a series of straight thread-like processes between the rods, this being especially the case when the eye is exposed to light.

# Function
The retinal pigment epithelium is involved in the phagocytosis of the outer segment of photoreceptor cells and it is also involved in the vitamin A cycle where it isomerizes all trans retinol to 11-cis retinal.
The retinal pigment eptihelium also serves as the limiting transport factor that maintains the retinal environment by supplying small molecules such as amina acid, ascorbic acid and D-glucose while remaining a tight barrier to choroidal blood borne substances. Homeostasis of the ionic environment is maintained by a delicate transport exchange system.

# Pathology
In the eyes of albinos, the cells of this layer contain no pigment.
Pineocytoma Classification

# Overview
There is no established system for the classification of .
OR
 may be classified according to  into  subtypes/groups: , , , and .
OR
 may be classified into  subtypes based on , , and .
 may be classified into several subtypes based on , , and .
OR
Based on the duration of symptoms,  may be classified as either acute or chronic.
OR
If the staging system involves specific and characteristic findings and features:
According to the , there are  stages of  based on the , , and . Each stage is assigned a  and a  that designate the  and .
OR
The staging of  is based on the .
OR
There is no established system for the staging of .

# Classification
There is no established system for the classification of .
OR
 may be classified according to  into  subtypes/groups:
OR
 may be classified into  subtypes based on:
 may be classified into several subtypes based on:
OR
Based on the duration of symptoms,  may be classified as either acute or chronic.
OR
If the staging system involves specific and characteristic findings and features:
According to the , there are  stages of  based on the , , and . Each stage is assigned a  and a  that designate the  and .
OR
The staging of  is based on the .
OR
There is no established system for the staging of .

# Classification
The 2007 WHO classification of central nervous system tumors divides pineal gland tumors into four groups:
- Pineocytoma (grade I)
- Pineal parenchymal tumors of intermediate differentiation (grade II or III)
- Papillary tumor of the pineal region (grade II or III)
- Pineoblastoma (grade IV)
According to the WHO classification of tumors of the central nervous system, pineocytoma is classified into a WHO grade I tumor.
Pontocerebellar hypoplasia

# Overview
Pontocerebellar hypoplasia (PCH) is a heterogeneous group of rare neurodegenerative disorders caused by genetic mutations and characterised by progressive atrophy of various parts of the brain such as the cerebellum or brainstem (particularly the pons). Where known, these disorders are inherited in an autosomal recessive fashion. There is no known cure for PCH.

# Classification
Pontocerebellar hypoplasia is classified as follows:
Pontine and cerebellar hypoplasia is also observed in certain phenotypes of X-linked mental retardation (so called MICPCH, OMIM: 300749).

# Signs and symptoms
There are different signs and symptoms for different forms of pontocerebellar hypoplasia, at least six of which have been described by researchers. All forms involve abnormal development of the brain, leading to slow development, movement problems, and intellectual impairment.
The following values seem to be aberrant in children with CASK gene defects: lactate, pyruvate, 2-ketoglutaric acid, adipic acid, and suberic acid which seems to support the thesis that CASK affects mitochondrial function.

# Causes
Pontocerebellar hypoplasia is caused by mutations in genes including VRK1 (PCH1); TSEN2, TSEN34 (PCH2); RARS2 (PCH6); and TSEN54 (PCH2 and PCH4). The genes associated with PCH3 and PCH5 have not yet been identified.
The mutated genes in PCH are autosomal recessive, which means that parents of an affected child each carry only one copy of the damaged gene. In each parent the other copy performs its proper function and they display no signs of PCH. A child inheriting two damaged copies of the gene will be affected by PCH.

# Mechanism
Mutations in the genes that cause PCH produce faults in the production of chemicals, usually enzymes, that are required for the development of nerve cells (neurons) and for properly processing RNA, which is needed for any cell to function normally. The exact mechanism by which PCH affects the development of the cerebellum and pons is not well understood.

# Outcomes
The severity of different forms of PCH varies, but many children inheriting the mutated gene responsible do not survive infancy or childhood; nevertheless, some individuals born with PCH have reached adulthood.
Popliteal vein compression
Keywords and synonyms: poplitieal vein syndrome, popliteal vein entrapment

# Overview
Popliteal vein compression is a disorder in which there is either anatomic or funcitonal compression of outflow from the popliteal vein.

# Pathophysiology

## Anatomic Compression
There can be non dynamic / static compression of the vein from extrinsic anatomic structures.  In this scenario there is a muscle or fibrous tissue surrounding the vein that is compressing it.

## Functional Compression
In this scenario, the calf muscles on either side of the vein are in normal anatomic location, however when the muscle of the calf are tensed, the vein is compressed.  There is no fixed anatomic structure compressing the vein, and there is dynamic compression.

# Epidemiology and Demographics
This is a very rare disorder.

# Risk Factors
Symptoms may develop in the following scenarios:
- Muscle building exercises in young women
- Recurrence of varicose veins in the region supplied by the short saphenous vein
- Sural vein thrombosis in the absence of thrombophilia

# Diagnosis

## Symptoms
- The patient may be asymptomatic and the disorder can go unrecognized.
- Muscle cramps with exertion or prolonged standing

## Physical Examination

### Extremities
- Edema or swelling of the lower extremity that is positional
- Non edematous swelling of the calf muscle in athletes
- Asymmetry of the circumference of the anterior tibialis muscle and the posterior tibialis muscle

# Laboratory Findings

## Duplex Ultrasound
The diagnosis is confirmed by duplex scanning investigation with active and passive maneuvers, whose aim is to detect the position that triggers this condition.

## Dynamic Venography

## MRI
MRI is more sensitive than ultrasound in detecting compression of the venous structures.

# Treatment
Although popliteal artery entrapment is a well-defined anatomic entity, whose treatment has received a broad consensus of approval, extrinsic compression of the popliteal vein syndrome, more recently recognized, is rarely systematically sought. Treatment of this condition is subject to differences in terms of methods and indications. Some have proposed the term popliteal vein entrapment syndrome to associate so-called functional forms and anatomical forms, observed more rarely.  An anatomic form involves our ability to specifically see a muscle or fibrous tissue surrounding the vein or artery. A functional form involves our ability to see venous compression on imaging studies, but no evidence of a discrete abnormal structure compressing the vein. 
explore the popliteal space of one leg and divide any fibrous tissue or muscle surrounding the vein, and see if this gives you some degree of relief in the postoperative period.

## Complications of Surgery
- There can be a long incision post operatively given that the vein must be explored along its entire course.
- Nerve damage
- Deep vein thrombosis
Posterior auricular artery
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The posterior auricular artery is a small artery and arises from the external carotid artery, above the Digastric muscle and Stylohyoid muscle, opposite the apex of the styloid process.
It ascends posteriorly beneath the parotid gland, along the styloid process of the temporal bone, between the cartilage of the ear and the mastoid process of the parietal bone along the lateral side of the head. The posterior auricular artery supplies blood to the scalp posterior to the auricle and to the auricle itself.
Posterior ethmoidal artery
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The posterior ethmoidal artery, smaller than the anterior ethmoidal artery, branches off from the ophthalmic artery when it reaches the medial wall of the orbit. It passes between the upper border of the medial rectus muscle and superior oblique muscle to pass through the posterior ethmoidal canal, to supply posterior ethmoidal cells, and, entering the cranium, gives off a meningeal branch to the dura mater, and nasal branches which descend into the nasal cavity through apertures in the cribriform plate, anastomosing with branches of the sphenopalatine.
This artery supplies the posterior ethmoidal air sinuses, dura of the anterior cranial fossa, and the upper part of the nasal mucosa.
Posterior scrotal arteries
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The posterior scrotal arteries are branches of the internal pudendal artery.
Potassium-sparing diuretic
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Potassium-sparing diuretic refers to diuretic drugs that do not promote the secretion of potassium into the urine. They are used as adjunctive therapy, together with other drugs, in the treatment of hypertension and management of congestive heart failure.

# Mechanism of action
Potassium-sparing diuretics decrease sodium reabsorption at collecting tubules, inducing diuresis; decrease activity of aldosterone at collecting tubules.

# Indications
Potassium-sparing diuretics are generally used in combination with other diuretic drugs (e.g. loop diuretics) that would otherwise tend to lower the potassium levels to potentially dangerous low levels (hypokalemia). The combination therefore helps maintain a normal reference range for potassium.

# Side effects
On their own this group of drugs may raise potassium levels beyond the normal range, termed hyperkalemia, which risks potentially fatal arrhythmias.

# Chemical structure
Potassium-sparing diuretics do not share any obvious chemical similarities, except for the steroid-structure of the aldosterone antagonists. Those in clinical use include:
- Amiloride
- Triamterene
- Aldosterone antagonists:
Spironolactone
Eplerenone
- Spironolactone
- Eplerenone
Praseodymium(III) chloride
Praseodymium(III) chloride (PrCl3), also known as praseodymium trichloride, is a compound of praseodymium and chlorine.  It is a blue-green solid which rapidly absorbs water on exposure to moist air to form a light green heptahydrate.

# Chemical properties
Praseodymium(III) chloride is a moderately strong Lewis acid, which ranks as "hard" according to the HSAB concept.  Rapid heating of the hydrate may cause small amounts of hydrolysis.  PrCl3 forms a stable Lewis acid-base complex K2PrCl5 by reaction with potassium chloride; this compound shows interesting optical and magnetic properties.
Aqueous solutions of praseodymium(III) chloride can be used to prepare insoluble praseodymium(III) compounds, for example praseodymium(III) phosphate or  praseodymium(III) fluoride:
PrCl3(aq)  +  K3PO4(aq)    PrPO4(s)  +  3 KCl(aq)
PrCl3(aq)  +  3 NaF(aq)   PrF3(s)  +  3 NaCl(aq)

# Preparation
Praseodymium(III) chloride can be prepared as a green aqueous solution by reaction of either praseodymium metal or praseodymium(III) carbonate and hydrochloric acid.  The anhydrous halide may alternatively be prepared from praseodymium metal and hydrogen chloride.
2 Pr(s)  +  6 HCl(aq)    2 PrCl3(aq)  +  3 H2(g)
Pr2(CO3)3(s)  +  6 HCl(aq)    2 PrCl3(aq)  +  3 CO2(g)  +  3 H2O(l)
Anhydrous PrCl3 can be made by dehydration of the hydrate either by slowly heating to 400 C with 4-6 equivalents of  ammonium chloride under high vacuum,, or by heating with an excess of thionyl chloride for four hours,.  The anhydrous halide may alternatively be prepared from praseodymium metal and hydrogen chloride.  It is usually purified by high temperature sublimation under high vacuum.

# Uses
PrCl3 has been used to increase the activity of Template:Praseodymium6O11 catalysts, which can be used for the oxidation of methane to ethene.  This process is becoming an important route to ethene for the manufacture of polyethylene (a common plastic).  There are no major uses for praseodymium(III) chloride, though it can be used as a starting point for the preparation of other praseodymium salts.

# Precautions
Praseodymium compounds are of low to moderate toxicity, although their toxicity has not been investigated in detail.  Wear gloves and goggles.