Persius/hicric huggingface dataset:
Pathognomonic
Pathognomonic (often misspelled as pathognomic) is an adjective of Greek origin ( ), often used in medicine, which means diagnostic for a particular disease. A pathognomonic sign is a particular sign whose presence means, beyond any doubt, that a particular disease is present. It is derived from the Greek pathos (, disease) and gnomon (, "judge"). Labelling a sign or symptom "pathognomonic" represents a marked intensification of a "diagnostic" sign or symptom.
While some findings may be classic, typical or highly suggestive in a certain condition, they may not occur uniquely in this condition and therefore may not directly imply a specific diagnosis. A pathognomonic finding on the other hand allows immediate diagnosing, since there are no other conditions in the differential diagnosis. A pathognomonic sign or symptom can sometimes be absent in a certain disease, since the term only implies that when it is present, the doctor instantly knows the patient's illness.
Singular pathognomonic signs are relatively uncommon. Examples of pathognomonic findings include Koplik's spots inside the mouth in measles, the palmar xanthomata seen on the hands of people suffering from hyperlipoproteinemia, or a tetrad of rash, arthralgia, abdominal pain and kidney disease in a child with Henoch-Schonlein purpura.

# Pathognomonic signs
Sucking louse
Sucking lice (Anoplura) have around 500 species and represent the smaller of the two traditional suborders of lice. The Anoplura are all blood-feeding ectoparasites of mammals. They can cause localised skin irritations and are vectors of several blood-borne diseases.
Children appear particularly susceptible to attracting lice, possibly due to their fine hair.
At least three species of Anoplura are parasites of humans; the human condition of being infested with sucking lice is called pediculosis. Pediculus humanus is divided into two subspecies, Pediculus humanus humanus, or the body louse, sometimes nicknamed "the seam squirrel" for its habit of laying of eggs in the seams of clothing, and Pediculus humanus capitis, or the head louse. Phthirus pubis (the pubic louse) is the cause of the condition known as crabs.
de:Tierlause
eo:Anopluroj
lt:Uteles
sv:Blodsugande loss
Pelvic cavity
The pelvic cavity is a body cavity that is bounded by the bones of the pelvis and which primarily contains reproductive organs, the urinary bladder, and the rectum.

# Borders
The boundaries are as follows:

# Greater and lesser pelvis
The lesser pelvis (or "true" pelvis" only includes structures inferior to the pelvic brim.
For example, the pelvic splanchnic nerves arising at S2-S4 is in the true pelvis, but the femoral nerve from L2-L4 is only in the "false pelvis", or greater pelvis.

# Ligaments

# Arteries
- internal iliac artery
- median sacral artery
- ovarian artery

# Nerves
- sacral plexus
- splanchnic nerves

# Additional images
- Articulations of pelvis. Anterior view.
- The arteries of the pelvis.
- Dissection of side wall of pelvis showing sacral and pudendal plexuses.
- Sacral plexus of the right side.
Pendant group
A pendant group or side group is a group of molecules attached to a backbone chain of a long molecule. Usually, this molecule would be a polymer.
For example, the phenyl groups are the pendant groups on a polystyrene chain.
Large, bulky pendant groups such as adamantyl usually raise the glass transition temperature (Tg) of a polymer by preventing the chains from sliding past each other easily. Short alkyl pendant groups may lower the Tg by a lubricant effect.
Pentachromacy
Pentachromacy is the condition of possessing five independent channels for conveying color information. Organisms with pentachromacy are called pentachromats. For these organisms, the perceptual effect of any arbitrarily chosen light from its visible spectrum can be matched by a mixture of no more than five different pure spectral lights.
The normal explanation of pentachromacy is that the organism's retina contains five types of cone cells with different absorption spectra. In practice the number of such receptor types may be greater than five, since different types may be active at different light intensities.
Some birds (notably pigeons) and butterflies have five or more kinds of color receptors in their retinae, and are therefore believed to be pentachromats, though psychophysical evidence of functional pentachromacy is not easy to come by. As with tetrachromacy, it is suggested that women carriers of genes for both mild forms of color blindness, deuteranomaly and protanomaly, are born with five different types of color-sensing cones though the red- and green-deficient cones are later lost.
Peptidoglycan
Peptidoglycan, also known as murein, is a polymer consisting of sugars and amino acids that forms a mesh-like layer  outside the plasma membrane of eubacteria.  The sugar component consists of alternating residues of -(1,4) linked N-acetylglucosamine and N-acetylmuramic acid residues.  Attached to the N-acetylmuramic acid is a peptide chain of three to five amino acids.  The peptide chain can be cross-linked to the peptide chain of another strand forming the 3D mesh-like layer.  Some Archaea have a similar layer of pseudopeptidoglycan. Peptidoglycan serves a structural role in the bacterial cell wall, giving structural strength, as well as counteracting the osmotic pressure of the cytoplasm. A common misconception is that peptidoglycan gives the cell its shape; however, whereas peptidoglycan helps maintain the structure of the cell, it is actually the MreB  protein that facilitates cell shape.
Peptidoglycan is also involved in binary fission during bacterial cell reproduction.
The peptidoglycan layer is substantially thicker in Gram-positive bacteria (20 to 80 nm) than in Gram-negative bacteria (7 to 8 nm), with the attachment of the S-layer. Peptidoglycan forms around 90% of the dry weight of Gram-positive bacteria but only 10% of Gram-negative strains.  In Gram-positive strains, it is important in attachment roles and sterotyping purposes.

# Antibiotic inhibition
Some antibacterial drugs such as penicillin interfere with the production of peptidoglycan by binding to bacterial enzymes known as penicillin-binding proteins or transpeptidases. Penicillin-binding proteins form the bonds between oligopeptide crosslinks in peptidoglycan.  For a bacterial cell to reproduce through binary fission, more than a million peptidoglycan subunits (NAM-NAG+oligopeptide) must be attached to existing subunits.  Mutations in transpeptidases that lead to reduced interactions with an antibiotic are a significant source of emerging antibiotic resistance.
Considered the human body's own antibiotic, lysozymes found in tears work by breaking the -(1,4)-glycosidic bonds in peptidoglycan (see below) and thereby destroying many bacterial cells.  Antibiotics such as penicillin commonly target bacterial cell wall formation (of which peptidoglycan is an important component) because animal cells do not have cell walls.

# Structure
The peptidoglycan layer in the bacterial cell wall is a crystal lattice structure formed from linear chains of two alternating amino sugars, namely N-acetylglucosamine (GlcNAc or NAG) and N-acetylmuramic acid (MurNAc or NAM).  The alternating sugars are connected by a -(1,4)-glycosidic bond. Each MurNAc is attached to a short (4- to 5-residue) amino acid chain, normally containing D-alanine, D-glutamic acid, and mesodiaminopimelic acid. These three amino acids do not occur in proteins and are thought to help protect against attacks by most peptidases. Cross-linking between amino acids in different linear amino sugar chains by an enzyme known as transpeptidase result in a 3-dimensional structure that is strong and rigid. The specific amino acid sequence and molecular structure vary with the bacterial species.
Pericoronitis

# Overview
Pericoronitis is a common problem in young adults with partial tooth impactions. It occurs when the tissue around the wisdom tooth has become infected because bacteria have invaded the area. Food impaction and caries (tooth cavity) are also problems associated with third molar pain.
Treatment for minor symptoms of pericoronitis (spontaneous pain, localized swelling, purulence/drainage, foul taste) is irrigation.  Major symptoms of pericoronitis (difficulty swallowing, enlarged lymph nodes, fever, limited mouth opening, facial cellulitis/infection) are usually treated with antibiotics. In most instances the symptoms will recur and the only definitive treatment is extraction. If left untreated, however, recurring infections are likely, and the infection can eventually spread to other areas of the mouth. The most severe cases are treated in a hospital and may require intravenous antibiotics and surgery.
The removal of the wisdom tooth (extraction) should occur at a time when the "infection" is not present, as extracting this tooth during the time of the acute/painful infection can cause the infection to spread to dangerous area around the throat. Therefore, a dentist will usually clean the area +/- prescribe antibiotics and wait for it to calm down until scheduling the extraction.
nl:Pericoronitis
Perihepatitis

# Overview
Perihepatitis is inflammation of the serous or peritoneal coating of the liver.
Perihepatitis is often caused by one of the inflammatory disorders of the female upper genital tract, known collectively as Pelvic inflammatory disease.
Some patients have sharp right upper abdominal quadrant pain. One of the complications of perihepatitis is Fitz-Hugh-Curtis syndrome.
Common bacterial causes for this disease are Chlamydia trachomatis and Neisseria gonorrhoeae.
Periodic acid
Periodic acid is HIO4 or H5IO6.
In dilute solution, periodic acid exists as H+ and IO4.  When more concentrated, orthoperiodic acid, H5IO6, is formed.  This can be obtained as a crystalline solid.  Orthoperiodic acid can be dehydrated to metaperiodic acid, HIO4.  Further heating gives diiodine pentoxide (I2O5) and oxygen; apparently the anhydride 'diiodine heptoxide' does not exist in nature but can be formed synthetically.
Thus, two forms of periodates exist. One relating to the acid HIO4, the other relating to H5IO6. The former results in metaperiodates (meta- meaning less water) and the latter, orthoperiodates (ortho- meaning more water).  Metaperiodates have solubilities and chemical properties similar to perchlorates (similar but larger ion size) though they are less oxidizing than perchlorates.
Periodic acid is also used in organic chemistry for structural analysis. Periodic acid will cleave a vicinal diol into two aldehyde fragments. This can be useful in determining the structure of carbohydrates.

# Notes and references
-  The name is not derived from "period", but from "iodine": per-iodic acid (compare iodic acid, perchloric acid), and it should thus be pronounced per-iodic and not as in the usual meaning of periodic.
de:Periodsaure
it:Acido periodico
Perseveration

# Overview
Perseveration is defined as uncontrollable repetition of a particular response, such as a word, phrase, or gesture, despite the absence or cessation of a stimulus, usually caused by brain injury or other organic disorder.
If an issue has been fully breached and discussed to a point of resolution it is not uncommon for something to trigger the re-investigation of the matter.  This can happen at any time during a conversation.  This is particularly true with those who have had traumatic brain injuries.
Those with Asperger's syndrome also display a form of perseveration in that they focus on one or a number of narrow interests. A person with Asperger's might go to a department store repeatedly to look at air conditioners.
Several researchers have tried to connect perseveration with a lack of inhibition; however, this connection could not be found, or was small.
Temporal bone
The temporal bones are situated at the sides and base of the skull.
The temporal bone supports that part of the face known as the temple.

# Parts
Each consists of five parts:
- Squama temporalis
- Mastoid portion
- Petrous portion
- Tympanic part
- Styloid process (temporal)

# Composition
The structure of the squama is like that of the other cranial bones: the mastoid portion is spongy, and the petrous portion dense and hard.

# Diagnosis

## Physical Examination

### Ear Nose and Throat
- Axial CT scan showing oblique left temporal bone fracture .
- Hemotympanum (blood in the middle ear) causes a bluish discoloration of the drum .
- Ruptured tympanic membrane and blood in the ear canal (surgeon's view).
- Battle's Sign. Bluish discoloration of the post-auricular region, associated with temporal bone fractures .
- Cerebrospinal fluid (CSF) otorrhea .
- Oblique left temporal bone  fracture line crossing the mastoid process, into Henle's spine and the external auditory canal (surgeon's view).

# Additional images
- The skull from the front.
- Sphenoid bone visible center right.
- Side view of the skull.
- Left infratemporal fossa.
- Sagittal section of skull.
- Articulation of the mandible. Lateral aspect.
- Base of the skull. Upper surface.
Phenoperidine

# Overview
Phenoperidine, marketed as its hydrochloride as Operidine or Lealgin, is an opioid used as a general anesthetic. It is a derivative of isonipecotic acid, like pethidine, and is metabolized in part to norpethidine. It is 20-200 times as potent as pethidine as an analgesic.
In humans 1 milligram is equipotent with 10 mg morphine. It has less effect on the circulatory system and is less hypnotic than morphine, but it has about the same emetic effect. The nausea can be prevented by giving droperidol or haloperidol. After an intravenous dose the analgesia sets in after 3-5 minutes.
Phenoperidine shares structural similarities with both pethidine and haloperidol (and related butyrophenone antipsychotics, e.g. droperidol). While not commonly used today in clinical practice, it is of historical interest as a precursor in the development of some of the most widely used neuroleptic drugs on the market today.
Phenylacetone
Phenylacetone, sometimes abbreviated P2P is an organic compound. It is a clear oil with a refractive index of 1.5168. This chemical is used in the manufacture of methamphetamine and amphetamine. Due to the illicit uses in clandestine chemistry, it was made a controlled substance in 1979 in the United States.

# Preparation
There are many methods in the scientific literature to prepare phenylacetone, and due to its controlled nature there is crossover into popular literature such as works by Uncle Fester and Alexander Shulgin. Not surprisingly there is also a fair amount of data available on the Internet relating to the preparation of phenylacetone.
A conceptually simple, although low-yielding, example of phenylacetone organic synthesis is the Friedel-Crafts alkylation of benzene with chloroacetone. The reaction is low yielding because the monoalkylation product is activated towards additional substitution at the ortho and para positions.
Phenylacetone synthesis via the Friedel-Crafts alkylation of Benzene with chloroacetone.
Phenylacetone can also be produced from many other chemicals.  For example, phenylacetic acid is distilled with lead acetate to yield phenylacetone.  Another is, benzaldehyde is reacted with nitroethane yielding phenyl-2-nitropropene, which is reduced, usually in the presence of acid, to phenylacetone.

# See Also
- MDP2P - a phenylacetone with a methylenedioxy group, using for making MDMA (Ecstasy).
de:Phenylaceton
Phenylethanol
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Phenethyl alcohol, or 2-phenylethanol, is the organic compound with the formula C6H5CH2CH2OH.  This colourless liquid occurs widely in nature, being found in a variety of essential oils, including rose, carnation, hyacinth, Aleppo pine, orange blossom, ylang-ylang, geranium, neroli, and champaca.  It is slightly soluble in water (2 mL/100 mL H2O), but miscible with ethanol and ether.
Phenethyl alcohol is an alcohol with a pleasant floral odor.  It is therefore a common ingredient in flavors and perfumery, particularly when the smell of rose is desired. It is used an an additive in cigarettes. It is also used as a preservative in soaps due to its stability in basic conditions. In biology it is of interest due to its antimicrobial properties.
Phospholamban
Phospholamban, also known as PLN or PLB, is a micropeptide protein that in humans is encoded by the PLN gene. Phospholamban is a 52-amino acid integral membrane protein that regulates the Calcium (Ca2+) pump in cardiac muscle cells.

# Function
This protein is found as a pentamer and is a major substrate for the cAMP-dependent protein kinase (PKA) in cardiac muscle. In the unphosphorylated state, phospholamban is an inhibitor of cardiac muscle sarcoplasmic reticulum Ca++-ATPase (SERCA2) which transports calcium from cytosol into the sarcoplasmic reticulum. When phosphorylated (by PKA) - disinhibition of Ca++-ATPase of SR leads to faster Ca++ uptake into the sarcoplasmic reticulum, thereby contributing to the lusitropic response elicited in heart by beta-agonists. The  protein is a key regulator of cardiac diastolic function. Mutations in this gene are a cause of inherited human dilated cardiomyopathy with refractory congestive heart failure.
When phospholamban is phosphorylated by PKA, its ability to inhibit SERCA2 is lost. Thus, activators of PKA, such as the beta-adrenergic agonist epinephrine (released by sympathetic stimulation), may enhance the rate of cardiac myocyte relaxation. In addition, since SERCA2 is more active, the next action potential will cause an increased release of calcium, resulting in increased contraction (positive inotropic effect). When phospholamban is not phosphorylated, such as when PKA is inactive, it can interact with and inhibit SERCA. The overall effect of phospholamban is to decrease contractility and the rate of muscle relaxation, thereby decreasing stroke volume and heart rate, respectively.

# Clinical significance
Gene knockout of phospholamban results in animals with hyperdynamic hearts, with little apparent negative consequence.
Mutations in this gene are a cause of inherited human dilated                cardiomyopathy             with refractory                congestive heart failure            .

# Discovery
Phospholamban was discovered by Arnold Martin Katz and coworkers in 1974.

# Interactions
PLN has been shown to interact with SLN and SERCA1.
Photomedicine
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Photomedicine is an interdisciplinary branch of medicine that involves the study and application of light with respect to health and disease.  Photomedicine may be related to the practice of various fields of medicine including dermatology, surgery, dentistry, optical diagnostics, cardiology, and oncology.

# Examples
- PUVA for the treatment of psoriasis
- Photodynamic therapy (PDT) for treatment of cancer and macular degeneration
- Free electron laser
- Laser hair removal
- Optical diagnostics, for example Optical Coherence Tomography using infrared light of coronary plaques
- Confocal microscopy and fluorescence microscopy of in vivo tissue
- Diffuse reflectance spectroscopy for in vivo quantification of pigments (normal and cancerous), and hemoglobin
- Perpendicular-polarized flash and fluorescence photography of the skin
Photoreceptor
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# Overview
Photoreceptor can refer to:
In anatomy/cell biology:
- Photoreceptor cell: a photosensitive cell, most commonly referring to a specialized type of neuron found in the retina of vertebrate eyes that is capable of phototransduction;
- Ocellus (invertebrate photoreceptor): a photoreceptor organ ("simple eye") of invertebrates often comprised of a few sensory cells and a single lens;
- Eyespot apparatus (microbial photoreceptor): the photoreceptor organelle of a unicellular organism that allows for phototaxis.
In biochemistry:
- Photoreceptor protein: a chromoprotein that responds to being exposed to a certain wavelength of light by initiating a signal transduction cascade;
- Photopigment: an unstable pigment that undergoes a physical or chemical change upon absorbing a particular wavelength of light; also see:
Photosynthetic pigment: molecules involved in transducing light into chemical energy.
- Photosynthetic pigment: molecules involved in transducing light into chemical energy.
In technology:
- Photodetector or photosensor: a device that detects light by capturing photons