Persius/hicric huggingface dataset:
Benzidine

# Overview
Benzidine is the trivial name for 4,4'-diaminobiphenyl, a carcinogenic aromatic amine which has been used as part of a test for cyanide and also in the synthesis of dyes. It has been linked to bladder cancer and pancreatic cancer.
In common with benzidine some other aromatic amines such as 2-aminonaphthalene have been withdrawn from use in almost all industries because they are so carcinogenic.
In the past a common test for blood used benzidine but this has largely been replaced by tests using phenolphthalein / hydrogen peroxide and luminol. An enzyme in blood causes the benzidine to be oxidized to a polymer which is blue coloured. The test for cyanide uses similar chemistry to give the blue colour.
Benzidine is a known human carcinogen. 

# Benzidine rearrangement
In a classic rearrangement reaction called the benzidine rearrangement benzidine is formed by reaction of the 1,2-diphenylhydrazine (PhNHNHPh) with acids. One plausible reaction mechanism has both hydrazine nitrogen atoms protonated after which a sigmatropic reaction takes place .
Dipeptide
A dipeptide is a molecule consisting of two amino acids joined by a single peptide bond.
Dipeptides are produced from polypeptides by the action of the hydrolase enzyme dipeptidyl peptidase. Dietary proteins  are digested to dipeptides and amino acids, and the dipeptides are absorbed more rapidly than the amino acids, because their uptake involves a separate mechanism. Dipeptides activate G-cells found in the stomach to secrete gastrin.
The Bergmann azlactone peptide synthesis is a classic organic synthesis for the preparation of dipeptides.  

# Examples of dipeptides
- Carnosine (beta-alanyl-L-histidine) is highly concentrated in muscle and brain tissues.
- Anserine (beta-alanyl-N-methyl histidine) is found in the skeletal muscle and brain of mammals.
- Homoanserine (N-(4-Aminobutyryl)-L-histidine) is another dipeptide identified in the brain and muscles of mammals.
- Kyotorphin (L-tyrosyl-L-arginine) is a neuroactive dipeptide which plays a role in pain regulation in the brain.
- Balenine (or ophidine) (beta-alanyl-N tau-methyl histidine) has been identified in the muscles of several species of mammal (including man), and the chicken.
- Aspartame (N-L-a-aspartyl-L-phenylalanine 1-methyl ester) is an artificial sweetener.
- Glorin (N- propionyl--L-glutamyl-L-ornithine--lac ethyl ester) is a chemotactic dipeptide for the slime-mould Polysphondylium violaceum.
- Barettin (cyclo-) is a cyclic dipeptide from the marine sponge Geodia barretti.
- Pseudoproline
Galactose
Galactose (Gal) (also called brain sugar) is a type of sugar which is less sweet than glucose and not very water-soluble. It is considered a nutritive sweetener because it has food energy.
Galactan is a polymer of the sugar galactose. It is found in hemicellulose and can be converted to galactose by hydrolysis.

# Sources
It is found in dairy products, in sugar beets and other gums and mucilages.
It is also synthesized by the body, where it forms part of glycolipids and glycoproteins in several tissues.

# Relationship to lactose
Galactose is a monosaccharide constituent, together with glucose, of the disaccharide lactose. The hydrolysis of lactose to glucose and galactose is catalyzed by the enzyme lactase, a -galactosidase. In the human body, glucose is changed into galactose in order to enable the mammary glands to secrete lactose.
Galactose and glucose are produced by hydrolysis of lactose by -galactosidase. This enzyme is produced by the lac operon in Escherichia coli (E. coli).

# Clinical significance
Two studies have suggested a possible link between galactose in milk and ovarian cancer.  Other studies show no correlation, even in the presence of defective galactose metabolism.  More recently, pooled analysis done by the Harvard School of Public Health showed no specific correlation between lactose containing foods and ovarian cancer, and showed statistically insignificant increases in risk for consumption of lactose at 30 g/d.  More research is necessary to ascertain possible risks.
There are some ongoing studies which suggest that galactose may have a role in treatment of focal segmental glomerulosclerosis (a kidney disease resulting in kidney failure and proteinuria). This effect is likely to be a result of binding of galactose to FSGS factor.

# Structure and isomerism
The first and last -OH groups point the same way and the second and third -OH groups point the other way. D-Galactose has the same configuration at its penultimate carbon as D-glyceraldehyde.
Galactose is a diastereomer of glucose.

# Liver galactose metabolism
In the liver, galactose is converted to glucose 1-phosphate.  Glucose 1-phosphate is later on converted to glucose 6-phosphate by the action of the enzyme phosphoglucomutase.  Shown below is a diagram  depicting galactose metabolism and the different enzymes involved in it.

# Metabolic disorders
There are 3 important disorders involving galactose depending on the type of deficient enzyme:
Beta cell

# Overview
Beta cells (beta-cells, -cells) are a type of cell in the pancreas in areas called the islets of Langerhans. They make up 65-80% of the cells in the islets.

# Function
Beta cells make and release insulin, a hormone that controls the level of glucose in the blood. There is a baseline level of insulin maintained by the pancreas, but it can respond quickly to spikes in blood glucose by releasing stored insulin while simultaneously producing more. The response time is fairly quick, taking approximately 10 minutes.
Apart from insulin, beta cells release C-peptide, a byproduct of insulin production, into the bloodstream in equimolar quantities. Measuring the levels of C-peptide can give a practitioner an idea of the viable beta cell mass.
-cells also produce amylin, also known as IAPP, islet amyloid polypeptide, a protein with unknown function.

# Pathology
- Diabetes mellitus type 1 is caused by the destruction or dysfunction of insulin-producing beta cells by the cells of the immune system.
- In Diabetes mellitus type 2, by contrast, beta cells decline gradually over time, and insulin resistance plays at least as large a role in the disease 
- Insulinoma is a rare tumor (usually benign) derived from beta cells. It results in recurrent and prolonged attacks of hypoglycemia.

# Research
Much research is being done in the field of beta-cell physiology and pathology. One major research topic is its effects on diabetes.  Many researchers are trying to find ways to use these beta-cells to help control or prevent diabetes. A major topic is the replication of adult beta-cells and the application of these to diabetes. The Larry L. Hillblom Islet Research Center at UCLA is a leading research center in the field, within the Diabetes and Endocrinology Research Center, directed by Dr.
Peter Butler. 
A team science effort also exists, known as the Beta Cell Biology Consortium (BCBC).  The BCBC is responsible for facilitating interdisciplinary approaches that will advance the understanding of pancreatic islet development and function. The long-term goal of the BCBC is to develop a cell-based therapy for insulin delivery.
Bevirimat
Bevirimat is a anti-HIV drug derived from a betulinic acid-like compound, first isolated from Syzygium claviflorum, a Chinese herb. It is believed to inhibit HIV by a novel mechanism, so-called maturation inhibition.   It is not currently FDA-approved, but is undergoing clinical trials conducted by the pharmaceutical company Panacos.

# Clinical trials
In December 2007, some results of the Phase IIb trial were released.  Thomson Financial News reported that, "some patients respond 'very well' to the drug, while another population 'does not respond as well at current dose levels.'" Panacos said it intends to add a group to the study at a higher dosage.

# Pharmacokinetics
According to the only currently available study, "the mean terminal elimination half-life of bevirimat ranged from 56.3 to 69.5 hours, and the mean clearance ranged from 173.9 to 185.8 mL/hour." 

# Mechanism of action
Bevirimat targets the gag polyprotein precursor, the main structural protein responsible for assembly and budding of virion particles. By binding to the gag polyprotein, bevirimat prevents its cleavage by the protease enzyme into functional subunits.  Unlike the protease inhibitors, bevirimat binds the gag protein, not the protease enzyme. The resulting virus particles are structurally defective and are incapable of spreading infection around the body.   For unknown reasons, protease inhibitor-resistant HIV-1 was hypersensitive to bevirimat in vitro.
Biguanide
Biguanides (ATC A10 BA) form a class of oral antihyperglycemic drugs used for diabetes mellitus or prediabetes treatment.

# Examples
Examples of biguanides:
- metformin - widely used in treatment of diabetes mellitus type 2 combined with obesity
- phenformin - withdrawn from the market in most countries due to toxic effects
- buformin - withdrawn from the market due to toxic effects
Proguanil is a biguanide used not for diabetes, but rather as an antimalarial drug.

# History
Galega officinalis was used for diabetes treatment in traditional medicine for centuries. In the 1920s, guanidine compounds were discovered in Galega extracts. Animal studies showed that these compunds lowered blood glucose levels. Some less toxic derivatives, synthalin A and synthalin B, were used for diabetes treatment, but after the discovery of insulin they were forgotten for the next several decades. Biguanides were reintroduced into Type 2 diabetes treatment in the late 1950s. Initially phenformin was widely used, but its potential for sometimes fatal lactic acidosis resulted in its withdrawal from pharmacotherapy in most pharmacopeias (in the U.S. in 1977). Metformin has a much better safety profile, and it is the principal biguanide drug used in pharmacotherapy worldwide.

# Pharmacotherapy
Biguanides do not affect the output of insulin, unlike other hypoglycemic agents such as sulfonylureas and meglitinides.  Therefore, they are not only effective in Type 2 diabetics, but they can also be effective in Type 1 patients in concert with insulin therapy.

# Mode of action
The exact mode of action of biguanides is not fully elucidated. However, in hyperinsulinemia, biguanides can lower fasting levels of insulin in plasma.  Their therapeutic uses derive from their tendency to reduce gluconeogenesis in the liver, and as a result, reduces the level of glucose in the blood.  Biguanides also tend to make the cells of the body more willing to absorb glucose already present in the blood stream, and there again reducing the level of glucose in the plasma.

# Side effects and toxicity
The most common side effect is diarrhea and dyspepsia, occurring in up to 30% of patients.  The most important and serious side effect is lactic acidosis. Phenformin and buformin are more prone to cause acidosis than metformin therefore they have been practically replaced by it.  However, when metformin is combined with other drugs (combination therapy), hypoglycemia and other side effects are possible.
Bile duct

# Overview
A bile duct is any of a number of long tube-like structures that carry bile.
Bile, required for the digestion of food, is excreted by the liver into passages that carry bile toward the hepatic duct, which joins with the cystic duct (carrying bile to and from the gallbladder) to form the common bile duct, which opens into the intestine.
The biliary tree (see below) is the whole network of various sized ducts branching through the liver.
The path is as follows: Bile canaliculi  Canals of Hering   interlobular bile ducts  intrahepatic bile ducts  left and right hepatic ducts merge to form   common hepatic duct exits liver and joins   cystic duct (from gall bladder) forming   common bile duct   joins with pancreatic duct   forming ampulla of Vater   enters duodenum

# Common bile duct
The top half of the common bile duct is associated with the liver, while the bottom half of the common bile duct is associated with the pancreas, through which it passes on its way to the intestine. It opens in the part of the intestine called the duodenum into a structure called the ampulla of Vater.

# Pathology
Blockage of the bile duct by a cancer, gallstones, or scarring from injury prevents the bile from being transported to the intestine and the active ingredient in the bile (bilirubin) instead accumulates in the blood. This condition is called jaundice and the skin and eyes become yellow from the bilirubin in the blood. This condition also causes severe itchiness from the bilirubin deposited in the tissues. In certain types of jaundice, the urine will be noticeably darker, and the stools will be much paler than usual. This is caused by the bilirubin all going to the bloodstream and being filtered into the urine by the kidneys, instead of some being lost in the stools through the ampulla of Vater.
Jaundice is commonly caused by conditions such as pancreatic cancer, which causes blockage of the bile duct passing through the cancerous portion of the pancreas; cholangiocarcinoma, cancer of the bile ducts; blockage by a stone in patients with gallstones; and from scarring after injury to the bile duct during gallbladder removal.

# Additional images
- Section across portal canal of pig. X 250.
Biopterin
Biopterin is a coenzyme that is produced within the body.
Defects in biopterin synthesis or regeneration can cause a form of hyperphenylalaninemia ("PKU") .
Biopterin is synthesized in several parts of the body, including the pineal gland and ???.
Biopterin deficiency has been associated with a variety of disorders, including dystonia  and ???.
Biosafety
Biosafety: prevention of large-scale loss of biological integrity, focusing both on ecology and human health.
Biosafety is related to several fields
- in ecology (referring to imported life forms from beyond ecoregion borders),
- in agriculture (reducing the risk of alien viral or transgenic genes, or prions such as BSE/"MadCow", reducing the risk of food bacterial contamination)
- in medicine (referring to organs or tissues from biological origin, or genetic therapy products, virus; levels of lab containment protocols measured as 1, 2, 3, 4 in rising order of danger),
- in chemistry (i.e., nitrates in water, PCB levels affecting fertility) and
- in exobiology (i.e., NASA's policy for containing alien microbes that may exist on space samples - sometimes called "biosafety level 5").
The international Biosafety Protocol deals primarily with the agricultural definition but many advocacy groups seek to expand it to include post-genetic threats: new molecules, artificial life forms, and even robots which may compete directly in the natural food chain.
Biosafety in agriculture, chemistry, medicine, exobiology and beyond will likely require application of the precautionary principle, and a new definition focused on the biological nature of the threatened organism rather than the nature of the threat.
When biological warfare or new, currently hypothetical, threats (i.e., robots, new artificial bacteria) are considered, biosafety precautions are generally not sufficient. The new field of biosecurity addresses these complex threats.
Biosafety level refers to the stringency of precautions deemed necessary by the Centers for Disease Control and Prevention (CDC) for laboratory work with infectious materials.

# Gallery
- Centers for Disease Control microbiologist, and Special Pathogens Branch (SPB) staff member, as he was in the process of counting viral plaques within fixed monolayers of cells, set atop a light box. From Public Health Image Library (PHIL).
Birthmark
A birthmark is a blemish on the skin formed before birth. They are part of the group of skin lesions known as naevi. The cause of birthmarks is unknown, but may include cellular damage due to radiation or chemicals. Some types seem to run in families.
In Italian and Middle Eastern cultures they are called voglie in Italian or wiham in Arabic, both of which translate to "wishes" because, according to folklore, they are caused by unsatisfied wishes of the mother during pregnancy. For example, if a pregnant woman does not satisfy a sudden wish or craving for strawberries, it's said that the infant might bear a strawberry mark.

# Types
A number of different types of birthmarks are known that include, but are not limited to, stork bites, Mongolian blue spots, strawberry marks, cafe au lait spots, congenital melanocytic nevi, and port-wine stains.
Bisabolol
Bisabolol, or more formally -(-)-bisabolol or also known as levomenol, is a natural monocyclic sesquiterpene alcohol.   It is a colorless viscous oil that is the primary constituent of the essential oil from German chamomile (Matricaria recutita).  It is almost insoluble in water and glycerin, but well soluble in ethanol.  The enantiomer, -(+)-bisabolol, is also found naturally but is rare.  Synthetic bisabolol is usually a racemic mixture of the two, -()-bisabolol.
Bisabolol has a weak sweet floral aroma and is used in various fragrances.  It has also been used for hundreds of years in cosmetics because of its perceived skin healing properties.  Bisabolol is known to have anti-irritant, anti-inflammatory and anti-microbial properties.
A structurally related compound known as -bisabolol (CAS# ) differs only in the position of the tertiary alcohol functional group.
Bisulfide
Bisulfide(or Bisulphide in UK Enlgish spelling), also called hydrosulfide, refers the anion with the formula HS, commonly written SH.  This species is the conjugate base of hydrogen sulfide:
In aqueous solutions, at pH less than 7, hydrogen sulfide is the dominant species; at pH > 7, bisulfide dominates.
A variety of salts are known, including sodium hydrosulfide, potassium hydrosulfide, and ammonium hydrosulfide.  Some compounds described as salts of the sulfide dianion contain primarily hydrosulfide.  For example, the hydrated form of sodium sulfide, nominally with the formula Na2S(H2O)9, is better described as NaSHNaOH(H2O)8.
Aqueous bisulfide absorbs light at around 230nm in the UV/VIS spectrum. Groups have used field spectrometers to measure the absorption due to bisulfide (and hence its concentration) continuously in the ocean and in sewage.
Bisulfide is sometimes confused with the disulfide dianion, S22.
ms:Bisulfida
Blackhead
A blackhead (medically known as an open comedo , plural comedones ) is a yellowish or blackish bump or plug on the skin. A blackhead is a type of acne vulgaris. It is caused by excess oils that have accumulated in the sebaceous gland's duct. Blackheads are typically caused by excessive oil and makeup, which can facilitate the multiplication of the bacterium Propionibacterium acnes, the predominant anaerobe of the normal skin flora. The substance found in these bumps mostly consists of keratin and modified sebum (an oily secretion of the sebaceous gland), which darkens (resembling dirt) as it oxidizes. 
Blackheads may be extracted by a professional such as a doctor, and should not be picked at without sterilized instruments designed for blackhead removal.
For information on the causes and treatment of blackheads, see the above linked acne vulgaris.
Blanching
Blanching is a cooking term that describes a process of food preparation wherein the food substance, usually a vegetable or fruit, is plunged into boiling water, removed after a brief, timed interval and finally plunged into iced water or placed under cold running water (shocked) to halt the cooking process.
Uses of blanching
- Peeling Blanching loosens the skin on some fruits or nuts, such as onions, tomatoes, plums, peaches, or almonds.
- Flavor Blanching enhances the flavor of some vegetables, such as broccoli, by releasing bitter acids stored in the cellular structure of the food.
- Appearance Blanching enhances the color of some (particularly green) vegetables by releasing gases trapped in the cellular material that obscure the greenness of the chlorophyll.  Since blanching is done - and halted - quickly, the heat does not have time to break down chlorophyll as well.
- Shelf life Blanching neutralizes bacteria and enzymes present in foods, thus delaying spoilage.  This is often done as a preparatory step for freezing and refrigerating vegetables.
Blanching can also describe deep frying in oil at a lower temperature as with the initial cooking of chips.
Blanching also weakens the structure of vegetables rendering them softer than fresh, this is beneficial for canning vegetables where the air in vegetables needs to be minimal.
Capillary
Capillaries are the smallest of a body's blood vessels, measuring 5-10 m, which connect arterioles and venules, and are important for the interchange of oxygen, carbon dioxide, and other substances between blood and tissue cells.

# Structure
The walls of capillaries are composed of only a single layer of cells, the endothelium. This layer is so thin that molecules such as oxygen, water and lipids can pass through them by diffusion and enter the tissues. Waste products such as carbon dioxide and urea can diffuse back into the blood to be carried away for removal from the body.
Capillary permeability can be increased by the release of certain cytokines.

# Transport across endothelium
The endothelium also actively transports nutrients, messengers and other substances.
Large molecules may be too big to diffuse across endothelial cells. In some cases, vesicles contained in the capillary membrane use endocytosis and exocytosis to transport material between blood and the tissues. Blood hydrostatic pressure varies along the length of the capillar, and is roughly 40 mm Hg at the atreiolar end and 15 mm Hg at the venus end. The opposing force from outside the capillary is osmotic pressure and is 25 mm Hg. The result is an outward movement of fluid and ions at the atreiolar end, and an influx of fluid at the venus end of the capillary.

# Immune response
In an immune response, the endothelial cells of the capillary will upregulate receptor molecules, thus "catching" immune cells as they pass by the site of infection and aiding extravasation of these cells into the tissue.

# Capillary bed
The "capillary bed" is the network of capillaries supplying an organ. The more metabolically active the cells, the more capillaries it will require to supply nutrients.
The capillary bed usually carries no more than 25% of the amount of blood it could contain, although this amount can be increased through autoregulation by inducing relaxation of smooth muscle.
The capillaries do not possess this smooth muscle in their own walls, and so any change in their diameter is passive.  Any signalling molecules they release (such as endothelin for constriction and nitric oxide for dilation) act on the smooth muscle cells in the walls of nearby, larger vessels, e.g. arterioles.

# Types
Capillaries come in three types:
- Continuous - Continuous capillaries have a sealed endothelium and only allow small molecules, water and ions to diffuse.
- Fenestrated - Fenestrated capillaries (derived from "fenestra," the Latin word for "window") have openings that allow larger molecules to diffuse.
- Sinusoidal - Sinusoidal capillaries are special forms of fenestrated capillaries that have larger openings in the epithelium allowing red blood cells and serum proteins to enter.
Dyscrasia
Dyscrasia (from Greek "Dyskrasia", meaning bad mixture), in Ancient Greek medicine,(This word is given in Aphorism 79 or Organon of Medicine by Dr. Samuel Hahnemann.) 
is the imbalance of the four humours (blood, black bile, yellow bile, and water(phlegm)) which were believed to exist in the body, and were believed to be the direct cause of all disease. This is similar to the Asian concept of Yin and Yang; it was believed that imbalance of the two polarities caused ailment.
It is still occasionally used in medical context for an unspecified disorder of the blood. Specifically it is defined in current medicine as a morbid general state resulting from the presence of abnormal material in the blood, usually applied to diseases affecting blood cells or platelets. 1
Antimetabolitic Agents such as Leucovorin, Methotrexate, etc. may cause blood dyscrasias.