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Glossary

This glossary provides definitions for terms widely used in beta cell biology and related fields of research. Browse through the categories.

» Glossary contains 56 entries as of July 28, 2014, 11:34 pm


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A1C

A diagnostic test that detects how much glucose has been present in the bloodstream over the last 2 to 3 months prior.  It is also called HbA1C, Hemoglobin A1C, and glycohemoglobin testing.

Specifically, the test measures the amount of glucose that is attached to hemoglobin, the oxygen-carrying molecule in the bloodstream.  The amount is proportional to the amount of glucose present in the bloodstream.

acinar cells

Acinar cells are located in the pancreas and secret digestive enzymes (exocrine function).

adult stem cell

An undifferentiated (unspecialized) precursor cell found in a differentiated (specialized) tissue that can proliferate indefinitely.  Under certain conditions, adult stem cells can differentiate into all the specialized cell types of the tissue from which they originated.

alloimmunity

The process by which an organism is immune to components (proteins, cells, or other antigens) from members of its own species, due to genetic diversity.  Alloimmunity is a common issue in organ transplantation.

alpha cells

Highly specialized cells found in the islets of Langerhans in the pancreas that produce and secrete glucagon into the bloodstream.

amino acid
One of the 20 building blocks of proteins. All amino acids contain an amino (NH2) group, a carboxyl group (COOH) and a side group (R). In proteins, amino acids are joined together when the NH2 group of one forms a bond with the COOH group of the adjacent amino acid. The side group is what distinguishes each of the amino acids from the others.

amino-terminus

The amino terminus is also known as the N-terminus.  It is the beginning region of a polypeptide chain.

anabolic

Referring to anabolism, a process by which molecules are constructed from smaller ones.

antibody

Any of a large family of glycoprotein molecules known as immunoglobulins.  There are normally present in the body and are produced by B-lymphocytes in response to an antigen which it neutralizes thereby creating an immune response.  Their name of immunoglobulin is derived from the fact that they migrate with globular proteins when antibody-containing serum is placed in an electric field.

antigen

A substance, whether innate to the organism or foreign to it, that stimulates an immune response in the form of production or mobilization of antibodies.

autoimmunity

A condition by which the host immune system mounts a response against its own tissues or organs.  Autoimmune responses typically lead to a wide array of medical conditions such as Type I (juveline) diabetes, rheumatoid arthritis, lupus erythematosus, etc...

beta cell

Highly specialized cells found in the islets of Langerhans in the pancreas that produce and secrete insulin into the bloodstream.

blood plasma
It is the liquid in which blood cells are suspended. It contains nutrients, proteins, metabolic products, hormones, electrolytes, and more.
carbachol
A cholinergic agonist capable of stimulating insulin release even under low glucose conditions.
carbohydrate

An organic molecule  that constitutes a major class of nutrients from foods like breads, fruit, vegetables, and dairy products.  Typically, carbohydrates are divided into two classes: simple (mono- and di-saccharides) and complex (polysaccharides).  Simple carbohydrates are sugars such as glucose, fructose, and sucrose, while complex carbohydrates include cellulose, glycogen, and starch.

carboxy-terminus

The end of a (poly)peptide chain. It is composed of the free Cα carboxyl group of the last amino acid in the peptide chain.

chromosome
The large and complex assembly of DNA and protein found in the cell nucleus (in eukaryotes).  The genetic information of all organisms is located in the genes that are a subset of DNA, and therefore a subset of chromosomes (in the case of eukaryotes).
C-peptide
A post-translational cleavage product in the reaction from proinsulin to insulin. 
diabetes insipidus
Diabetes insipidus is a disorder where insufficient vasopressin, a hormone produced by the brain that instructs kidneys to retain water, exists. The net effect resembles diabetes mellitus only in that the patient drinks and passes large amounts of water.
diabetes mellitus

A chronic metabolic disorder where a lack of insulin secretion and/or an increased cellular resistance to insulin results in elevated blood levels of glucose.  There are two types of diabetes mellitus, Type I (insulin-dependent or juvenile-onset) which is caused by an autoimmune response and Type II (non-insulin dependent or adult-onset).  Type II is the more common form and accounts for almost 90% of all cases. 

Complications include damage to the eyes, nervous system, kidneys, as well as the vascular system. There is no cure for this disorder, but there are methods to control it, including a proper diet, regular exercise, and insulin (if required). 

diaphoretic
An agent, or medicine, that promotes perspiration.
diuretic
An agent, or medicine, that lowers the blood pressure by promoting fluid loss, by urination.
duodenum

The proximal portion of the small intestine, between the stomach and the jejenum.  Interestingly, the word originates from the Latin duodenarius meaning twelve, as in twelve finger-breadths long.

Edmonton Protocol

A procedure developed by researcher James Shapiro and coworkers in Alberta, Canada for transplanting healthy insulin-producing pancreatic islets into patients with Type 1 diabetes.Once implanted, the new islets begin to make and release insulin.

Additional online resources which outline the procedure and its success are available:

embryonic stem cell

Embryonic stem cells (ESC) are isolated from the inner cell mass (ICM) of the blastocyst ? the stage of embryonic development when implantation occurs.  The cells have the potential to make any differentiated cell in the body and thus offer potential development of in cell-based therapies for clinical treatments.

emetic
An agent, or medicine, that causes nausea and vomiting.
endocrine

Related to internal secretion. Secretions from an endocrine gland include hormones, such as insulin, diffuse into the bloodstream and carried throughout the body to produce a physiological effect.

ghrelin cells

A recently characterized fifth cell type in the endocrine pancreas.  Also known as ε-cells.

Read a BCBC perspectives articles about ghrelin cells.

glucagon

A hormone secreted by pancreatic alpha cells in the pancreas that causes the body to release stores of energy in the form of glucose when blood sugar levels are low.

glucose

GlucoseA simple sugar (carbohydrate, monosaccharide) obtained from digested food and used a source of physiological energy in the body.

Its molecular formula is C6H12O6.

GLUT2
A facilitative glucose transporter that is present in pancreatic beta cells. This transporter uptakes the circulating glucose into the beta cells which serves as the initial trigger in insulin secretion.
GLUT4

GLUT4 is a glucose transporter.  Insulin regulates glucose uptake, by muscles and other tissues, into the cells by recruiting membrane vesicles containing the GLUT4 glucose transporter.  The process of facultative diffusion drives the uptake of glucose into the cells, removing it from the blood stream.

hemoglobin

The protein molecule that carries oxygen (to the cells of the body from the lungs) and carbon dioxide (from the cells to the lungs) in the bloodstream.  Hemoglobin contains iron as cofactor which gives blood its characteristic color due to the oxidation state of the cofactor.

homeostasis

The physiological process by which the internal bodily systems are maintained at equilibrium despite variations in environmental conditions.  Examples of such processes are body temperature, acid-base balance (pH), and blood pressure.

hormone

A chemical manufactured in specialized cells that are secreted and used by other cells and tissues to perform their function.

hyperglycemia

An abnormally high concentration of glucose (sugar) in the circulating blood, seen especially in patients with untreated diabetes mellitus.

hypoglycemia

An abnormally low concentration of glucose (sugar) in the circulating blood.

As related to diabetes, it is also known as "insulin shock" and is a grave medical condition that can lead to shaking, palpitations, seizure, coma and even death.

immunosuppressive

A treatment or medication that suppresses the immune system.

insulin

A hormone secreted by pancreatic beta cells that allow other cells in the body to absorb glucose to use as energy.

insulinopathy
A monogenic form of adult-onset diabetes due to mutations in the insulin gene.
intron
Segment of DNA, in eukayotes,  which is interspersed among the protein-coding sequences (exons) in a gene.  It is excised from the mRNA transcript in order to convert it into a mature messenger RNA molecule containing only coding sequences that can be translated into the amino acid sequence of a coded polypeptide.
islets of Langerhans

The islets of Langerhans comprise a cluster of highly specialized cells in the pancreas. These cells produce and secrete hormones that help the body break down and use food.

Discovered in 1869 by Paul Langerhans, the islets contain four types of cells: alpha cells, which produce glucagon; beta cell, which produce insuline; delta cells, which produce somatostatin; and PP, which produce pancreatic polypeptide.

molecule

The smallest unit of any substance that retains all the physical and chemical properties of that substance and which can exist alone in a free state. It consists of a single atom or a group of atoms covalently bonded together.

For example,a single water molecule (H2O) consists of a single oxygen (O) atom bonded to two hydrogen (H) atoms. A single droplet of water contains millions of water molecules! Larger molecules such as DNA, proteins, lipids, hormones work in concert to maintain life.

neurite

Neurite outgrowth is the extension of axonal processes from the cell body. It is a natural part of early development.

pancreas

A gland the size of a fist that is located behind the stomach.   It secretes both digestive enzymes into the lower end of the stomach and it also secretes hormones vital to the regulation of various processes, including the regulation of blood sugar by the hormone insulin.

PDX-1
An early transcription factor involved in pancreatic development and regeneration.
phosphorylation

Phosphorylation is the covaleng addition of a phosphate (PO4) group to a protein or a small molecule. The activity of many proteins is regulated by phosphorylation of hydroxyl-containing residues (serine, threonine, tyrosine) by various protein kinases.

pluripotent

A cell that is able to differentiate into any of three major tissue types: ectoderm, mesoderm, and ectoderm. Despite their ability to differentiate into any type of cell, they cannot however develop into a full organism.

polyuria
Excessive urination. A common symptom of diabetes.
preproinsulin

Preproinsulin is the primary translation product of the insulin gene.  It is composed of 110 amino acids with the following sequence:

MALWMRLLPLLALLALWGPDPAAAFVNQ
HLCGSHLVEALYLVCGERGFFYTPKTRREA
EDLQVGQVELGGGPGAGSLQPLALEGSLQ
KRGIVEQCCTSICSLYQLENYCN

(swissprot accession ID P01308)

In this initial state, preproinsulin is inactive and needs to be processed to proinsulin and then to insulin in order to be biologically active.

somatostatin

A hormone believed to play a role in regulating growth hormone and also playing a role in the regulation of glucagon and insulin.

stem cell

An undifferentiated (unspecialized) precursor cell found in a differentiated (specialized) tissue that can proliferate indefinitely and eventually differentiate into a single type of cell.

Stem cells come in two forms: adult stem cells and embryonic stem cells.

teratogen

A chemical or physical agent or substance that can lead to non-heritable birth defects.

transcription

The process where the genetic information encoded in a linear sequence of nucleotides in one strand of DNA is copied into an exactly complementary sequence of RNA.

translation

The conversion of genetic information, in the form of mRNA, into polypeptides, with the aid of ribosomes and tRNAs.

triglyceride
A triester of glycerol and fatty acids commonly found in fats and oils.