Actelion Ltd
Actelion Ltd is the holding company which encompasses Actelion Pharmaceuticals Ltd, and the subsidiaries of Actelion Pharmaceuticals, headquartered in Allschwil.

Actelion Pharmaceuticals Ltd
Actelion is a biopharmaceutical company specializing in the research, development and marketing of new medicines with a mechanism of action that is based on the functions of the endothelium. The head office of Actelion is located at Gewerbestrasse 16, CH-4123 Allschwil, Switzerland. The subsidiaries of Actelion Ltd carry the name Actelion Pharmaceuticals (plus the country name, i.e., Actelion Pharmaceuticals Canada) and are responsible for sales and marketing of Actelion's pharmaceutical products.

ADME
Absorption dissolution metabolism excretion (ADME)

Alzheimer's disease
Senile dementia occurring at an early age. One of Actelion's major drug discovery projects focuses on Alzheimer's disease.

Antagonist
A substance that opposes or alleviates the pharmacological effect of another compound.

Aspartyl protease
One of two protein families that Actelion focuses on as therapeutic targets. Aspartyl proteases (or acid proteases) consist of a family of enzymes. Today more than 50 members of the aspartyl protease family are known. Eight are currently known in humans (pepsin, gastricsin, napsin, renin, cathepsin D and E, BACE 1 & 2). Their physiological roles are emerging as well as their links to pathophysiological states such as cancer, inflammation, cardiovascular and neurological diseases. Actelion has chosen several targets from this class. See also G-protein coupled receptors.

Aspartyl protease inhibitor
A substance that inhibits the pharmacological effect of a specific aspartyl protease enzyme.

Automated fluorescence technologies
Fluorescent dyes are employed to monitor enzymatic activities in test tubes or to follow changes in intracellular second messenger levels in whole cells. At Actelion such fluorescence assays were made amenable for automation and high-throughput.

Biopharmaceutical company
A biopharmaceutical company uses biological science and techniques to produce pharmaceutical products.

Bosentan (Tracleer®)
The first oral dual endothelin receptor antagonist for the treatment of pulmonary arterial hypertension, developed by Actelion Pharmaceuticals Ltd. Tracleer® has been approved in the US, Canada, Australia, Switzerland and Europe to date for the treatment of pulmonary arterial hypertension (PAH), including primary pulmonary hypertension (PPH) and PAH related to other diseases such as scleroderma.

Calcium channel blockers
Group of vasodilating drugs that are effective in high blood pressure; and of some use in pulmonary arterial hypertension (PAH) at high doses.

Cardiovascular disease
Disease relating to, or involving, the heart and blood vessels. One of Actelion's major drug discovery projects focuses on cardiovascular disease from the two protein families: G-protein coupled receptors and Aspartyl proteases.

Computer aided molecular modeling
Structural representation of large and small molecules in three dimensions with the help of powerful computer graphics and cleverly-written programs. Attractive as well as repulsive forces between molecules can be calculated and used by chemists in order to improve the properties of substances that eventually should become a drug.

Connective tissue disease (CTD)
The connective tissue diseases (CTDs), such as scleroderma and systemic lupus erythematosus (SLE), comprise a group of syndromes of unknown aetiology affecting as many as one person in 40, predominantly affecting women.

CREST syndrom
Special form of a collagenous disease associated with calcifications of the skin, blood flow disorder in the fingers, gastrointestinal function disorders, etc.; the disease is one of the risk factors for the development of PAH related to other conditions.

Crystallography and x-ray analysis
The process of focusing an x-ray beam onto protein or biomolecule crystals. The resulting interference pattern can be analyzed to determine the precise three-dimensional structure of a protein at atomic level.

Diastolic pressure
The lowest pressure to which blood pressure falls between contractions of the ventricles or when the heart relaxes.

Diuretics
A group of drugs that helps remove excess salt and water from the body by increasing the amount eliminated through urination, thereby reducing the heart's workload.

Drug discovery
The process of studying chemical entities in the laboratory to identify potential compounds for further pre-clinical and clinical development. This is the “research“ portion of drug research and development, or R & D.

Dual endothelin receptor antagonist
Substance that blocks the deleterious actions of endothelin (ET-1) at both endothelin receptors (ETA and ETB), since both receptors are involved in the vasoconstrictive, proliferative and profibrotic effects of ET in pathological situations like pulmonary arterial hypertension (PAH); Tracleer™ (bosentan) from Actelion is the first and only agent with the indication for PAH and the only endothelin receptor antagonist (ERA) currently available. Tracleer® and Veletri™ are “dual“ endothelin receptor antagonists.

Dyspnea
Shortness of breath, difficulty breathing. See PAH.

Echocardiography
Ultrasound examination of the heart by which the structure of the heart walls and heart valves, the wall thickness of heart atria and heart ventricles and their movement cycles are evaluated; important examination for the diagnosis of pulmonary arterial hypertension (PAH).

Edema
Swelling, resulting from fluid accumulation in tissue. When standing, edema occurs at the lower parts of the limbs.

Endothelin (ET-1)
Group of hormone-like substances (messenger substances) that are formed in the endothelium; endothelin-1 (ET-1) is the substance with the most powerful vasoconstricting effect in the body; ET-1 causes the growth of inelastic connective tissue in the vessel wall and promotes inflammation. In pathological situations increased local production of ET-1 seems to contribute to the development and severity of diseases like pulmonary arterial hypertension (PAH).

Endothelin is actually highly homologous to a potent venom toxin - called sarafotoxin - from a snake which kills its prey by myocardial infarction due to exaggerated contraction of cardiac vessels and interruption of blood supply to the heart.

Endothelin also participates in bronchoconstriction and plays a role in neurotransmitter release, inflammation, cell proliferation, and fibrosis. At the intracellular level, endothelin enhances the effects of other mediators, such as angiotensin II and catecholamines