Persius/hicric huggingface dataset:
Golfer's elbow
Synonyms and keywords: Medial epicondylitis

# Overview
Golfer's elbow, or medial epicondylitis, is an inflammatory condition of the elbow which in some ways is similar to tennis elbow.
The flexor muscles of the forearm, the muscles responsible for bending the fingers and thumb, clenching the fist and supinating the hand excluding biceps brachialis, come together in a common tendon which is inserted in to the medial epicondyle of the humerus at the elbow joint. In response to minor injury, or sometimes for no obvious reason at all, the point of insertion becomes inflamed.

# Causes
The condition is called Golfer's elbow because in making a golf swing this tendon is stressed; many people, however, who develop the condition have never handled a golf club.  It is also sometimes called Pitcher's elbow due to the same tendon being stressed by the throwing of objects such as a baseball, but this usage is much less frequent.

# History and Symptoms
The predominant symptom is pain on the medial aspect of the elbow joint, which is made much worse if the flexor muscles of the forearm arm under tension but may occur at rest. On examination the medial epicondyle of the humerus is exquisitely tender. There may be some weakness of flexor function, caused by pain-mediated reflex inhibition of function of the flexor muscles.

# Treatment
Simple analgesic medication has a place, as does more specific treatment with oral anti-inflammatory medications. The definitive treatment is, however, the injection into and around the inflamed and tender area of a long-acting glucocorticoid (steroid) agent. After causing an initial exacerbation of symptoms lasting 24 to 48 hours, this will produce a resolution of the condition in some five to seven days.
The ulnar nerve runs in the groove between the medial humeral epicondyle and the olecranon process of the ulna. It is most important that this nerve should not be damaged accidentally in the process of injecting steroid for a Golfer's elbow.

# Related Chapters
- Tennis elbow
Golgi's method
Golgi's method is a nervous tissue staining technique discovered by Italian physician and scientist Camillo Golgi (1843-1926) in 1873.  It was initially named the black reaction (la reazione nera) by Golgi, but it became better known as the Golgi stain or method later.
Golgi' staining was famously used by Spanish neuroanatomist Santiago Ramon y Cajal (1852-1934) to discover a number of novel facts about the organization of the nervous system, inspiring the birth of the neuron doctrine.

# Mechanism
The cells in nervous tissue are densely packed and little information on their structures and interconnections can be obtained if all the cells are stained. Furthermore, its thin filamentary extensionsthe axon and the dendritesare too slender and transparent to be seen with normal staining techniques. Golgi's method stains a limited number of cells at random in their entirety. The mechanism by which this happens is still largely unknown. Dendrites, as well as the cell soma, are clearly stained in brown and black and can be followed in their entire length, which allowed neuroanatomists to track connections between neurons and to make visible the complex networking structure of many parts of the brain and spinal cord.
Golgi's staining is achieved by impregnating fixed nervous tissue with potassium dichromate and silver nitrate. Cells thus stained are filled by microcrystallization of silver chromate.

# Technique
According to SynapseWeb , this is the recipe for Golgi's staining technique:
- Immerse a block (approx. 10x5 mm) of formol-fixed (or paraformaldehyde- glutaraldehyde-perfused) brain tissue into a 2% aqueous solution of potassium dichromate for 2 days
- Dry the block shortly with filter paper.
- Immerse the block into a 2% aqueous solution of silver nitrate for another 2 days.
- Cut sections approx. 20-100 m thick.
- Dehydrate quickly in ethanol, clear and mount (e.g., into Depex or Enthalan).
This technique has since been refined to substitute the silver precipitate with gold by immersing the sample in gold chloride then oxalic acid, followed by removal of the silver by sodium thiosulphate. This preserves a greater degree of fine structure with the ultrastructural details marked by small particles of gold. 

# Quote
Cajal said of the Golgi method:
Goodhart's law
Although Goodhart's law has been expressed in a variety of formulations, the essence of the law is that once a social or economic indicator or other surrogate measure is made a target for the purpose of conducting social or economic policy, then it will lose the information content that would qualify it to play such a role.  The law was named for its developer, Charles Goodhart (a chief economic advisor to the Bank of England).
Point 11
(a) Eliminate work standards (quotas) on the factory floor. Substitute leadership.
(b) Eliminate management by objective. Eliminate management by numbers, numerical goals. Substitute leadership.

# Origin
The law was first stated in a 1975 paper by Goodhart and gained popularity in the context of the attempt by the United Kingdom government of Margaret Thatcher to conduct monetary policy on the basis of targets for broad and narrow money, but the idea is considerably older. It is implicit in the economic idea of rational expectations.  While it originated in the context of market responses the Law has profound implications for the selection of high-level targets in organisations.
It has been asserted that the stability of the economic recovery that took place in the United Kingdom under John Major's government from late 1992 onwards was a result of Reverse Goodhart's Law: that, if a government's economic credibility is sufficiently damaged, then its targets are seen as irrelevant and the economic indicators regain their reliability as a guide to policy.

# Alternate Expressions
- A risk model breaks down when used for regulatory purposes.  (Danielsson, 2002)
- Goodhart's law is a generalized social science expression of the more well-known and economic-specific Lucas critique.
A related dictum is Campbell's Law:
The more any quantitative social indicator is used for social decision-making, the more subject it will be to corruption pressures and the more apt it will be to distort and corrupt the social processes it is intended to monitor.

# Examples in healthcare
- Colorectal cancer screening in U.S. veterans
- Glycemic control guidelines in elderlky patients with diabetes mellitus type 2.
- A possible example is Prostate cancer screening in elderly U.S. veterans

# Physician's role
While improving compliance with guidelines may improve patient outcomes, physicians have an ethical responsbility to balance care of the individual patient and the population health.

# Tactics to avoid harm from Goodhart's Law
The RAND's Assessing Care of Vulnerable Elders (ACOVE Project) proposes:
- Balancing measures such as adding to a quality measure for blood pressure control a quality measure for assessing otherstatic hypotention
- Adjusting measures for life expectancy rather than absolute age and consideration of "Lagtime-to-Benefit"
Other approaches:
- The N-of-1 trial
- Goals should not be viewed as invariable.
Great arteries

# Overview
Great arteries is a term used to refer collectively to the primary arteries of the heart, which include:
- Pulmonary artery: the vessel that carries oxygen-depleted blood from the right ventricle to the lungs.
- Aorta: the blood vessel through which oxygenated blood from the left ventricle enters the systemic circulation.
Nitrogen group
Group 15 of the periodic table(formerly numbered as Group V or Group VA) is also known by the collective name pnictogens.
This group has the defining characteristic that all the component
elements have 5 electrons in their outermost shell, that is 2 electrons in the s subshell and 3 unpaired electrons in the p subshell. They are therefore 3 electrons short of filling their outermost electron shell in their non-ionized state.  
The most important element of this group is nitrogen (N), which in its diatomic form is the principal component of air. 
Other members of the group include phosphorus (P), arsenic (As), antimony (Sb), bismuth (Bi) and ununpentium (Uup) (unconfirmed).
Binary compounds of the group can be referred to collectively as pnictides.  The spelling derives from the Greek  (pnigein), to choke or stifle, which is a property of nitrogen; they are also mnemonic for the two most common members, P and N.  The name pentels (from the Latin penta, five) was also used for this group at one time, stemming from the earlier group naming convention (Group VB).
These elements are also noted for their stability in compounds due to their tendency for forming double and triple covalent bonds. This is the property of these elements which leads to their potential toxicity, most evident in phosphorus, arsenic and antimony. When these substances react with various chemicals of the body, they create strong free radicals not easily processed by the liver, where they accumulate.  Paradoxically it is this strong bonding which causes nitrogen and bismuth's reduced toxicity (when in molecules), as these form strong bonds with other atoms which are difficult to split, creating very unreactive molecules. For example N2, the diatomic form of nitrogen, is used for inert atmosphere in situations where xenon or another noble gas would be prohibitively expensive.
The nitrogen group consits of two non-metals, two metalloids, and one metal.  All the elements in the group are a solid at room temperatue except for Nitrogen which is a gas at room temperature.
Guidewire core

# Overview
The core of a coronary guidewire determines many of the performance characteristics of the device.  The core of a coronary guidewire is usually ground to a taper towards the end and this is where the tip attaches to the core.  If guidewire core starts tapering more towards the tip, the coronary guidewire as a whole becomes more rigid, steerable and torquable.  The opposite happens when the core other coronary guidewire tapers more proximally allowing for a longer tip and a more flexible tip.  The core may be either continuous or joined.  If the core is joined then it is more likely to bend or prolapse when the guidewire is advanced.  Coronary guidewire cores that are made of stainless steel are stiffer, provide greater support, and provide greater torque control.  In contrast, coronary guidewire cores that are made of nitinol are much more flexible.

# Guidewire Core Composition
The guidewire core can be composed of either nitinol, stainless steel or a similar metal.

## Nitinol Guidewire Cores
Shown below is the structure of a guidewire with a nitinol core:

### Advantages Of A Nitinol Core
- Super-elastic alloy designed for kink resistance
- Excellent flexibility and steering
- Probably more durable in nature
- Better trackability
- Reduced prolapse

### Disadvantages Of A Nitinol Core
- A nitinol guidewire may be less torquable
- A nitinol guidewire core may store torque without necessarily transmitting the torque to the tip
- Wires with single nitinol cores sometimes "wind up" and store the torque

### Clinical Scenarios In Which A Nitinol Core May Be Useful
- As a result of their flexibility and durability, coronary guidewires with a nitinol core are more likely to enter a retroflexed circumflex coronary artery.

# Stainless Steel Guidewire Cores
Stainless steel was the original core material used in coronary guidewires.  Shown below is the structure of a stainless steel guidewire core (Courtesy of Abbott Vascular)

## Advantages Of A Stainless Steel Core
- The stainless steel core provides greater pushability, support, torquability, and good shapeability in core-to-tip wires.

## Disadvantages Of A Stainless Steel Core
- Tendency to kink
- Less flexible than newer core materials

# High Tensile Strength Stainless Steel
Shown below is the structure of a high tensile strength stainless steel guidewire core:

## Advantages of the High Tensile Strength Stainless Steel Core
- More durable than regular stainless steel
- Retains shape more
- Improved flexibility
- Improved steering and tracking

# Asahi Tru Torque Steel
Shown below is the structure of a Asahi Tru Torque Steel guidewire core:
HACEK organism

# Overview
HACEK organisms is a group of fastidious, slow growing, pleomorphic Gram negative bacilli which form part of the oropharynx commensals and require enhanced carbon dioxide tension for recovery in culture.

# Microbiology
HACEK refers to the initials of organisms including:
- Haemophilus influenzae, Haemophilus parainfluenzae, Aggregatibacter aphrophilus (formerly Haemophilus aphrophilus and Haemophilus paraphrophilus)
- Aggregatibacter actinomycetemcomitans (formerly Actinobacillus actinomycetemcomitans)
- Cardiobacterium hominis, Cardiobacterium valvarum
- Eikenella corrodens
- Kingella kingae, Kingella denitrificans

# Pathophysiology
The pathogenesis of HACEK endocarditis is presumed to be related to colonization of the oropharynx with bacteria that gain access to the vascular space following either trauma or local infection. In addition to valvular infections in the heart, these organisms can also produce other infections such as bacteremia, abscesses, peritonitis, otitis media, conjunctivitis, pneumonia, peritonitis, arthritis and osteomyelitis, and periodontal infections.

# Epidemiology and Demographics
HACEK organisms account for about 3% of cases of endocarditis,  with an insidious onset and subacute course. They are the most common Gram negative casue of endocarditis among patients who do not use intravenous drugs. Most patients with HACEK endocarditis have preexisting cardiac defects or prior dental manipulations. The duration of symptoms prior to diagnosis is reported to be longer than 2 weeks but shorter than 6 months.

# Diagnosis

## Laboratory Studies
Given the fastidious growth requirements, HACEK bacteria are a recognized cause of culture-negative endocarditis. The organisms can be identified after subculture on 5 to 8% sheep blood and chocolate agar at 35 to 37C for 48 to 72 hours in an aerobic atmosphere containing 5 to 10% CO2. Although the mean duration for incubation of blood cultures until detection of growth is 3 to 5 days, up to 30 days may be required. Biochemical properties are used to differentiate members of the HACEK group. However, biopatterns may be varied by inoculum volume and growth conditions, which prompts the utilization of molecular techniques such as 16S rRNA sequencing.

# Treatment
The treatment of endocarditis caused by HACEK organisms should be based on antimicrobial susceptibility tests, including tests for -lactamase ctivity. Since many of these organisms are slow growing, such tests can be problematic. Although there are limited published clinical data demonstrating the efficacy of ceftriaxone or ampicillin-sulbactam therapy, these drugs should be considered the regimens of choice for the treatment of patients with HACEK endocarditis. Fluoroquinolones should be considered as an alternative agent for patients unable to tolerate -lactam therapy. The American Heart Association recommends that native-valve and prosthetic-valve endocarditis be treated for 4 weeks and 6 weeks, respectively. HACEK endocarditis is associated with a favorable prognosis, with a cure rate of 82 to 87% of patients with medical treatment alone or associated with surgery.
Haldane effect
The Haldane effect is a property of hemoglobin first described by the British physician John Scott Haldane.
Deoxygenation of the blood increases its ability to carry carbon dioxide; this property is the Haldane effect. Conversely, oxygenated blood has a reduced capacity for carbon dioxide. This  is a consequence of the fact that reduced (deoxygenated) hemoglobin is a better proton acceptor than the oxygenated form.
In red blood cells, the enzyme carbonic anhydrase catalyzes the conversion of dissolved carbon dioxide to carbonic acid, which rapidly dissociates to bicarbonate and a free proton:CO2 + H2O -> H2CO3 -> H+ + HCO3-
By Le Chatelier's principle, anything that stabilizes the proton produced will cause the reaction to shift to the right, thus the enhanced affinity of deoxyhemoglobin for protons enhances synthesis of bicarbonate and accordingly increases capacity of deoxygenated blood for carbon dioxide.  The majority of carbon dioxide in the blood is in the form of bicarbonate.  Only a very small amount is actually dissolved as carbon dioxide, and the remaining amount of carbon dioxide is bound to hemoglobin.
In addition to enhancing removal of carbon dioxide from oxygen-consuming tissues, the Haldane effect promotes dissociation of carbon dioxide from hemoglobin in the presence of oxygen. In the oxygen-rich capillaries of the lung, this property causes the displacement of carbon dioxide to plasma as venous blood enters the alveolus and is vital for alveolar gas exchange.
The general equation for the Haldane Effect is:
H+ + HbO2  H+.Hb + O2

# Clinical significance
In patients with lung disease, lungs may not be able to increase alveolar ventilation in the face of increased amounts of dissolved CO2.
This partially explains the observation that some patients with emphysema might have an increase in PaCO2 (arterial dissolved carbon dioxide) following administration of supplemental oxygen.
Hamelia patens
Hamelia patens (Firebush, hummingbird bush, scarlet bush or "redhead") is a large perennial shrub or small tree from subtropical and tropical America. The Firebush has a native range that runs from Texas in southern United States to as far south as Argentina.
It has orangish-red tubular flowers, which recruit hummingbirds and butterflies for pollination. Their corolla varies much in length, making it attractive to a wide range of pollinators. The fruit is a small dark red berry.
Despite its somewhat scraggy appearance, this is a valuable garden tree in warmer climates and even in temperate ones, as long as the soil remains above freezing. Hummingbirds attracted by its flowers and other birds feeding on the fruit will also forage on small insects found in the vicinity, helping to keep down pests. The fruit have an refreshing, acidic taste and besides being much liked by some birds, they are also edible for humans; in Mexico, they are made into a fermented drink.
Also, the plants are used in folk medicine against a range of ailments. A number of active compounds have been found in firebush, but no scientific study of its medical usefulness has been conducted yet.

# Footnotes
-  USDA (2006)
-  Jump up to: 2.0 2.1 Welch (2003)
-  Fenster (1991)
-  Including maruquine and isomaruquine, pteropodine and isopteropodine, palmirine, rumberine, seneciophylline and stigmast-4-ene-3,6-dione. The bark contains significant amounts of tannins. See Duke (2007).
Hamlet (cigar)
Hamlet are a well known brand of cigar produced by Benson and Hedges. They are available in several varieties, miniatures and also a regular length. They are regularly referred to as the 'mild cigar' in their advertising.
Hamlet cigars were first launched in the UK in 1964. More recently, Hamlet cigars have been launched in a number of western European markets.
They are most famous in the UK for their comical advertisements, cast by Paul de Freitas, which feature someone in an unfavourable position who finds that lighting a Hamlet cigar and smoking it relives them of their problems temporarily - played to the tune of Bach's Air on a G String.
Since the ban on tobacco advertising in the UK and much of Europe was implemeted, the adverts are no longer aired.
Hayflick limit
The Hayflick limit was discovered by Leonard Hayflick in 1965. Hayflick observed that cells dividing in cell culture divided about 50 times before dying. As cells approach this limit, they show more signs of old age.
The limit to the number of times a cell divides has been noted in all human cell types that have been fully differentiated, as well as in other organisms.  It varies from cell type to cell type, and more significantly from organism type to organism type.  The human limit is around 52.  The limit has been linked to the shortening of telomeres, a region of DNA at the end of chromosomes.
The limit is believed to be one of the causes of aging.  It is believed that if the shortening of telomeres can be slowed or prevented, life expectancy can be extended.  Much research is happening in this area. The only known way of circumventing the Hayflick limit is with the enzyme telomerase, which regenerates telomeres during DNA replication.
Stem cells, by definition, have not yet been fully differentiated, and therefore many of these cells may continue to regenerate new cells for the entire lifespan of the organism, without limit, thus constituting a notable exception to the Hayflick limit in humans and other organisms.  While the manifestations of the constant regenerative effects of stem cells is most easily seen in tissues which must constantly produce replacements for existing cells, such as skin and blood cells, stem cells of one form or another are found in every tissue of the human body, even if only as dormant stem cells known as "spore-like cells".
Cancer cells constitute the other main exception to the limits on cell division.  It is believed that the Hayflick limit exists principally to help prevent cancer.  If a cell becomes cancerous and the Hayflick limit is approaching, the cell will only be able to divide a certain number of times.  Once it reaches this limiting number of divisions, the formed tumour will no longer be able to reproduce and the cells will die off.  Cancers become problems after having reactivated telomerase-encoding genes.  Cells that have found a way around the limit are referred to as "immortal". Individual cells will still die, but the group of immortalized cells produced from cell division of an immortal cell has no limit as to how many times cell division might take place among the cells that constitute such a group of immortalized cells.
It is believed by some that some or all cancers start off as stem cells that become genetically damaged over their long lives .  This would mean they already aren't limited by the Hayflick limit and can easily metastasize into the pool of cells in their final cell type destination.
Head of radius

# Overview
The head of the radius has a cylindrical form, and on its upper surface is a shallow cup or fovea for articulation with the capitulum (or capitellum) of the humerus.
The circumference of the head is smooth; it is broad medially where it articulates with the radial notch of the ulna, narrow in the rest of its extent, which is embraced by the annular ligament.
The deepest point in the fovea is not axi-symmetric with the long axis of the radius, creating a cam effect during pronation and supination.