Persius/hicric huggingface dataset:
Helen B. Taussig
Helen Brooke Taussig, M.D., (May 24, 1898 - May 20, 1986) was an American cardiologist, working in Baltimore and Boston, who founded the field of pediatric cardiology.  Notably, she helped develop the Blalock-Taussig shunt in cooperation with Dr. Alfred Blalock and Vivien Thomas, to treat blue baby syndrome.

# Background
Helen Taussig was born in Cambridge, Massachusetts.  Her father was Harvard economist Frank W. Taussig, and her mother Edith was one of the first students at Radcliffe College. Her mother died when she was eleven.  She struggled with severe dyslexia through her early school years, overcoming it only with diligent work and extensive tutoring from her father.
She graduated Cambridge School for Girls in 1917, then studied for two years at Radcliffe before earning a bachelor's degree from the University of California, Berkeley in 1921.  She then studied at both Harvard Medical School and Boston University before pursuing her postgraduate cardiac research at Johns Hopkins University.
She suffered from deafness throughout the latter part of her career, and learned to use lip-reading to listen to her patients, and her fingers in place of a stethoscope to feel the rhythm of their heartbeats.

# Medicine
Dr. Taussig did extensive work on anoxemia, or blue baby syndrome, which led to the development of the pioneering infants surgery called the Blalock-Taussig shunt, first performed by Taussig and Dr. Alfred Blalock on an 11-month old baby girl on November 29,1944.  Taussig wrote the book Congenital Malformations of the Heart in 1947, and received the 1954 Albert Lasker Award for Clinical Medical Research for her work.  In 1959, she was one of the first women to be awarded a full professorship at Johns Hopkins University.
She was also one of the key doctors to advise the American Food and Drug Administration to prevent thalidomide from going to market in the United States, after studying European children born with phocomelia because of the improperly tested drug.
In 1964, Taussig received the Medal of Freedom from President Lyndon Johnson, and in 1965 she became the first female president of the American Heart Association.  Johns Hopkins University named the "Helen B. Taussig Children's Pediatric Cardiac Center" after her, and in 2005 the School of Medicine named one of its four colleges in her honor.
Hemagglutination

# Overview
Hemagglutination (also haemagglutination) is a specific form of agglutination that involves red blood cells. It has two common uses in the laboratory: blood typing and the quantification of virus dilutions.

# Blood Typing
Using antibodies that bind to the A or B blood group in a sample of blood, one can determine the blood type of the individual being tested.
For example, if antibodies that bound to the A blood group were added and agglutination occurred, it could be concluded that the blood was either type A or type AB.
Then if antibodies that bound the B group were added and agglutination did not occur, it could be concluded that the blood was type A.
In blood grouping the patient's serum is tested against RBCs of known blood groups and also the patient's RBCs are tested against known serum types. In this way the patient's blood group is confirmed from both RBCs and serum. A direct Coombs test is also done on the patient's blood sample in case there are any confounding antibodies.

# Viral Hemagglutination Assay
Many viruses attach to molecules present on the surface of red blood cells. A consequence of this is that - at certain concentrations - a viral suspension may bind together (agglutinate) the red blood cells thus preventing them from settling out of suspension. Usefully, agglutination is rarely linked to infectivity, attenuated viruses can therefore be used in assays.
By serially diluting a virus suspension into an assay tray (a series of wells of uniform volume) and adding a standard amount of blood cells an estimation of the number of virus particles can be made. While less accurate than a plaque assay, it is cheaper and quicker (taking just 30 minutes).
This assay may be modified to include the addition of an antiserum. By using a standard amount of virus, a standard amount of blood cells and serially diluting the antiserum, one can identify the minimum inhibitory concentration of the antiserum (the greatest dilution which inhibits hemagglutination).

# Related chapters
- Hemagglutination assay

# Resources
- Hemagglutination: Presented by the University of Virginia
- Hemagglutination at the US National Library of Medicine Medical Subject Headings (MeSH)
Hemangioblastoma

# Overview
Hemangioblastoma of the central nervous system is a benign tumor (WHO grade I) that is typically cystic and can occur throughout the central nervous system. It is a tumor composed of hemangioblasts, a type of stem cell that normally give rise to blood vessels or blood cells. Its name breaks down to Greek roots as follows: Haema (blood), angeion (vessel), blastos (embryonic), oma (tumor).

# Locations
Predominant locations include the cerebellum and spinal cord.

# Causes
Hemangioblastomas can occur "sporadically", or as a component of the von Hippel-Lindau disease (VHL).
VHL is inherited in an autosomal dominant pattern. The VHL gene behaves as a tumor suppressor, i.e. mutation of the VHL gene predisposes individuals to development of a wide variety of benign and malignant tumors. These tumors occur in target tissues such as the kidneys, adrenal gland, central nervous system and retina.
The most common tumors in VHL besides hemangioblastomas are pheochromocytomas, retinal angiomas, clear cell renal cancer and renal cysts, pancreatic cysts and pancreatic islet cell tumors, and cystadenomas of the epididymis. All of these tumors can also occur sporadically outside VHL, presumably with a similar underlying pathophysiology.)

# Presentation
These tumors, whether benign (usual) or malignant (rarer), may cause clinically significant problems, for example angiomas in the brain or spinal cord may press on nerve or brain tissue.
As an angioma grows, the walls of the blood vessels may weaken and leak, causing damage to surrounding tissues. Blood leakage from angiomas in the retina can interfere with vision.
Cysts may also grow around angiomas.
Cerebral hemangioblastomas are commonly seen at MR imaging as cystic lesion with a solid enhancing mural nodule. The solid nodule give low signal on diffusion weighted imaging (DWI) with resultant increase in the apparent diffusion coefficient (ADC).
- T2
- T1
- T1 with GAD
- T1 with GAD

# Differentiating hemangioblastoma from Other Diseases
Hemangioblastoma  must be differentiated from other diseases that cause seizure, visual disturbance, and constitutional symptoms, such as:
- Oligodendroglioma
- Meningioma
- Astrocytoma
- Pituitary adenoma
- Schwannoma
- primary CNS lymphoma
- Medulloblastoma
- Ependymoma
- Craniopharyngioma
- Pinealoma
- AV malformation
- Brain aneurysm
- Bacterial brain abscess
- Tuberculosis
- Toxoplasmosis
- Hydatid cyst
- CNS cryptococcosis
- CNS aspergillosis
- Brain metastasis
For more information click here.
Hemostatic agent

# Overview
Hemostatic agents (also spelled haemostatic) are substances that promote hemostasis (stop bleeding).  Styptics (also spelled stiptics) are a specific type of hemostatic agent that work by contracting tissue to seal injured blood vessels.  Other hemostatic agents used in medicine work by adsorbing water from blood, causing platelet aggregation and promoting coagulation.

# Medicine
Hemostatic agents have been gaining popularity for use in emergency bleeding control, especially in military medicine. They are available in two forms - as a granular powder poured on wounds, or embedded in a dressing.
There are currently two hemostatic chemicals used in commercial products. Chitosan is used in Celox (a granular powder) and HemCon (a dressing). Zeolite is used in QuikClot (a dressing).

# Styptics
Styptics for personal use are typically made from alum or titanium dioxide, and come in the form of styptic pencils, used to treat shaving cuts, and styptic powder, for staunching wounds from cutting animal nails.

## Pencil
A styptic or hemostatic pencil is a short stick of medication, usually anhydrous aluminum sulfate (a type of alum) or titanium dioxide, which is used for staunching blood by causing blood vessels to contract at the site of the wound.
Before safety razors were invented, it was an essential part of a shaving kit and was used to seal cuts caused by improper shaving.  Some people continue to use styptic pencils for minor skin wounds from safety or electric razors.
While effective at stopping blood loss, some who use it feel that the sting of the medication as it takes effect can be worse than the pain of the cut itself. More "natural" ingredients such as aloe add a "more soothing alternative".
A frequent source of confusion appears to be the difference between styptic and caustic pencils which are not used to staunch minor cuts.

### TV ad
In the 1970s, a TV ad for a popular brand of razor featured a father teaching his son how to shave, cautioning him that the blade on his old, generic razor was "sharp, very sharp", and made an audible scraping sound as he showed his son the proper method. Cut to the sales pitch for the improved Gillette or Schick product. Cut back to the father and son: "Now, this, this thing here, is a styptic pencil."

## Powder
Styptic powder is used to stop bleeding from nails that are clipped too closely. This powder is generally used on animals, such as dogs, cats, rabbits, and birds, where the vein is found in the center of the nail.
Styptic powder can also be used to stop bleeding caused by cuts and nicks while shaving.
Herbert C. Brown
Herbert Charles Brown (May 22, 1912  December 19, 2004) was a chemist and Nobel Prize in Chemistry laureate for his work with organoboranes
Brown was born Herbert Brovarnik in London to Ukrainian Jewish immigrants. He moved to the United States in June 1914, at the age of two.  In autumn 1935, he entered the University of Chicago, completed two years of studies in three quarters, and earned a B.S. in 1936.  That same year, he became a naturalized US citizen.  On February 6, 1937, Brown married Sarah Baylen, the person he credits with making him interested in hydrides of boron, a topic related to the work in which he with Georg Wittig won the Nobel prize in Chemistry in 1979.  Two years after starting graduate studies, he earned a Ph.D. in 1938, also from the University of Chicago.  Unable to find a position in industry, he decided to accept an offer for a position as a post-doctorate.  This became the beginning of his academic career.  He became an Instructor at the University of Chicago in 1939, and held the position for four years before moving to Wayne University in Detroit as an Assistant Professor.  In 1946, he was promoted to an Associate Professor.  He became a Professor of Inorganic Chemistry at Purdue University in 1947 and joined Alpha Chi Sigma there in 1960.  He held the position of Professor Emeritus from 1978 until his death in 2004. The Herbert C. Brown Laboratory of Chemistry was named after him on Purdue University's campus. He was an honorary member of the International Academy of Science.
During World War II, while working with Hermann Irving Schlesinger, Brown discovered a method for producing sodium borohydride (NaBH4), which can be used to produce boranes, compounds of boron and hydrogen. His work led to the discovery of the first general method for producing asymmetric pure enantiomers. The elements found as initials of his name H, C and  B were his working field.
Brown was quick to credit his wife Sarah with supporting him and allowing him to focus on creative efforts by handling finances, maintaining the house and yard, etc. According to Brown, after receiving the Nobel prize in Stockholm, he carried the medal and she carried the US$100,000 award.
He died December 19, 2004, at a hospital in Lafayette, Indiana after a heart attack.  Surviving are his son and his granddaughters.
Milroy's Disease
Synonyms and keywords: Milroy's syndrome; Nonne-Milroy-Meige syndrome; Hereditary lymphedema

# Overview
Milroy's disease is a familial disease characterised by lymphedema, commonly in the legs, caused by congenital abnormalities in the lymphatic system. Disruption of the normal drainage of lymph leads to fluid accumulation and hypertrophy of soft tissues.

# Historical Perspective
It was named by Sir William Osler for William Milroy, an American physician, who described a case in 1892, though it was first described by Rudolf Virchow in 1863.

# Pathophysiology

## Genetics
An association with the gene FLT4 has been described.

# Epidemiology and Demographics
This disease is more common in women.

# Natural History, Complications, Prognosis
The defect in Milroy's disease is present from birth and symptoms are usually first experienced in childhood.

# Diagnosis

## Symptoms
- Unilateral leg edema: The most common problem is one-sided leg swelling, unilateral edema, which is progressive and can affect both legs.
- Steatorrhea: Impaired intestinal lymphatics can cause steatorrhea due to impaired transport of chylomicrons.

# Physical examination

## Gallery

### Extremities
- url = >
- url = >

## Laboratory Findings
Defective lymphocyte circulation can cause lymphopenia and impaired cell-mediated immunity.
Herpetic whitlow

# Overview
A herpetic whitlow is a lesion on a finger or thumb caused by the herpes simplex virus.  In children the primary source of infection is the orofacial area, and it is commonly inferred that the virus (in this case commonly HSV-1) is transferred by the chewing or sucking of fingers or thumbs.  In adults it is more common for the primary source to be the genital region, with a corresponding preponderance of HSV-2. It is also seen in adult health care workers such as dentists because increased exposure to the herpes virus.

# Pathophysiology

## Transmission
It is typically contracted by healthcare workers that come in contact with the virus; it is most commonly contracted by dental workers and medical workers exposed to oral secretions. Again, the HSV seronegative person is at highest risk of acquiring this condition. It is often observed in thumb-sucking children with primary HSV-1 infection, and in adults aged 20 to 30 following contact with by HSV-2-infected genitals.

# Causes
- Herpes whitlow is a painful infection that typically manifest itself on fingers or thumbs and occasionally on the toes, or on the nail cuticle, and is caused by HSV-1 or HSV-2.
- Herpes whitlow is also caused by autoinoculation of HSV into broken skin prior to an infected person developing antibodies against the virus (e.g. during primary infection before seroconversion).
- If someone has a cold sore and puts their finger in their mouth then a herpes infection whitlow may appear. Herpes whitlows are frequently found among dentists and dental hygienists.

# Natural History, Complications and Prognosis
The herpes whitlow lesion usually heals in two to three weeks.

# Diagnosis

## History and Symptoms
Symptoms of herpetic whitlow include swelling, reddening, and tenderness of the skin of infected finger. This may be accompanied by fever and swollen lymph nodes.

## Physical Examination

### Extremities
Small, clear vesicles initially form that merge and becomes cloudy. Associated pain often seems large relative to the physical symptoms.
- Herpetic whitlow in a young child who had earlier developed herpes gingivostomatitis
- Vesiculobullous lesions of the fingers of a patient with Herpetic Whitlow

# Treatment

## Medical Therapy
Although it is a self-limited illness, topical antivirals, particularly topical acyclovir, have been shown to be effective in decreasing the duration of symptoms. One should never try to lance or surgically debride the lesion, as it may make it worse (cause a superinfection or cause encephalitis).
Historadiography
Historadiography is a technique formerly utilized in the fields of histology and cellular biology to provide semiquantitative information regarding the density of a tissue sample.  It is usually synonymous with microradiography.  This is achieved by layering a ground section of mineralized tissue (such as bone) with photographic emulsion on a glass slide and exposing the sample to a beam of X-rays. After developing the emulsion, the resulting radiograph can be viewed with a microscope. A side-by-side comparison with a slide containing radiographs of various substances of known mass can provide a rough mass estimate, and therefore a rough approximation of the concentration of calcium salts in the sample.
Historadiography has also been used to visualize staining of tissue, such as spinal cord samples with thorotrast, which contains thorium that is opaque to X-rays.
Over recent decades researchers have generally lost interest in historadiography.  The most recent publication using the term (1998) to be indexed in PubMed referred to autoradiography of tritium incorporated in thymidine.
Homoscedasticity
In statistics, a sequence or a vector of random variables is homoscedastic if all random variables in the sequence or vector have the same finite variance. This is also known as homogeneity of variance.
The complement is called heteroscedasticity.  (Note: The alternative spelling homo- or heteroskedasticity is equally correct and is also used frequently.)
Serious violations in homoscedasticity (assuming a distribution of data is homoscedastic when in actuality it is heteroscedastic) result in underemphasizing the  Pearson coefficient.  Assuming homoscedasticity assumes that variance is fixed throughout a distribution.

# Assumptions of a Regression Model
In simple linear regression analysis, one assumption of the fitted model is that the standard deviation of the error terms are constant and does not depend on the x-value. Consequently, each probability distributions for each y (response variable) has the same standard deviation regardless of the x-value (predictor). In short, this assumption is homoscedasticity.

# Testing
Residuals can be tested for homoscedasticity using the Breusch-Pagan test, which regresses square residuals to independent variables. The BP test is sensitive to normality so for general purpose the Koenkar-Basset or generalized Breusch-Pagan test statistic is used. For testing for groupwise heteroscedasticity, the Goldfeld-Quandt test is needed.
Hormone receptor
A hormone receptor is a receptor protein on the surface of a cell or in its interior that binds to a specific hormone. The hormone causes many changes to take place in the cell.
Binding of hormones to hormone receptors often trigger the start of a biophysical signal that can lead to further signal transduction pathways, or trigger the activation or inhibition of genes.

# Types of Hormone Receptors
- Peptide hormone receptors are often transmembrane proteins. They are also called G-protein-coupled receptors, sensory receptors or ionotropic receptors. These receptors generally function via intracellular second messengers, including  cyclic AMP (cAMP), inositol 1,4,5-trisphosphate (IP3) and the calcium (Ca2+)-calmodulin system.
- Steroid hormone receptors and related receptors are generally soluble proteins that function through gene activation.  Their response elements are DNA sequences (promoters) that are bound by the complex of the steroid bound to its receptor.  The receptors themselves are zinc-finger proteins.  These receptors include those for glucocorticoids, estrogens, androgens, thyroid hormone (T3), calcitriol (the active form of vitamin D, and the retinoids (vitamin A).
Hospital network
A hospital network is a network or group of hospitals that work together to coordinate and deliver a broad spectrum of services to their community.  A  hospital system or health care system is 2 or more hospitals owned, sponsored, or contract managed by a central organization. 

# Benefits and controveries
To avoid financial losses due to shrinking reimbursements and rising costs as well as improving quality of care and avoid duplication of services, hospitals may consolidate certain services at one hospital. However, patients may need to travel further if those services are no longer offered at their local hospital. 

# International
- Adventist Health International - 13 countries
- Aga Khan Health Services - Central and South Asia and East Africa - 9 hospitals
- Apollo Hospitals is an Indian healthcare corporation that operates 38 hospitals in South Asia

# Canada
- Eastern Health  - 7 hospitals
- Health Care Corporation of St. John's 

# United States

## US Government networks
- Indian Health Service - 33 hospitals
- Veterans Health Administration
- Military medicine - United States Department of Defense - See Category:United States military hospitals
Air Force Medical Service
Army Medical Department
Navy Bureau of Medicine and Surgery 
- Air Force Medical Service
- Army Medical Department
- Navy Bureau of Medicine and Surgery
Hounsfield scale

# Overview
The Hounsfield scale is a quantitative scale for describing radiodensity.

# Definition
The radiodensity of distilled water at standard pressure and temperature (STP) is defined as zero Hounsfield units (HU).  The  radiodensity of air at STP is defined as -1000 HU. For a material X with linear attenuation coefficient \mu_{X} , it is defined as
\frac{\mu_X-\mu_{H_2O}}{\mu_{H_2O}}\times 1000
where \mu_{H_2O} is the linear attenuation coefficient of water at the same (effective) energy.

## Rationale
The above standards were chosen as they are universally available references and suited to the key application for which computed axial tomography was developed: imaging the internal anatomy of living creatures based on organized water structures and mostly living in air, e.g. humans.

# The HU of common substances

# History
It was established by Sir Godfrey Newbold Hounsfield, one of the principal engineers and developers of computed axial tomography (CAT, or CT scans).
CT machines were the first imaging devices for detailed visualization of the internal three-dimensional anatomy of living creatures, initially only as tomographic reconstructions of slice views or sections.  Since the early 1990s, with advances in computer technology and scanners using spiral CT technology, internal three-dimensional anatomy is viewable by three-dimensional software reconstructions, from multiple perspectives, on computer monitors. By comparison, conventional X-Ray images show only compressed two-dimensional images of complex anatomy, i.e. radiodensity shadows.