The premise to the design of atracurium and several of its congeners stemmed from the knowledge that a bis-quaternary structure is essential for neuromuscular-blocking activity: ideally, therefore, a chemical entity devoid of this bis-quaternary structure via susceptibility to inactive breakdown products by enzymic-independent processes would prove to be invaluable in the clinical use of a drug with a predictable onset and duration of action. Hofmann elimination provided precisely this basis: It is a chemical process in which a suitably activated quaternary ammonium compound can be degraded by the mildly alkaline conditions present at physiological pH and temperature. In effect, Hofmann elimination is a retro-Michael addition chemical process. It is important to note here that the physiological process of Hofmann elimination differs from the non-physiological Hofmann degradation process: the latter is a chemical reaction in which a quaternary ammonium hydroxide solid salt is heated to 100 °C, or an aqueous solution of the salt is boiled. Regardless of which Hofmann process is referenced, the end-products in both situations will be the same: an alkene and a tertiary amine. The approach to utilizing Hofmann elimination as a means to promoting biodegradation had its roots in much earlier observations that the quaternary alkaloid petaline (obtained from the Lebanese plant Leontice leontopetalum) readily underwent facile Hofmann elimination to a tertiary amine called leonticine upon passage through a basic (as opposed to an acidic) ion-exchange resin.
Heberdens nodes are hard or bony swellings that can develop in the distal interphalangeal joints (DIP) (the joints closest to the end of the fingers and toes). They are a sign of osteoarthritis and are caused by formation of osteophytes (calcific spurs) of the articular (joint) cartilage in response to repeated trauma at the joint.Heberdens nodes typically develop in middle age, beginning either with a chronic swelling of the affected joints or the sudden painful onset of redness, numbness, and loss of manual dexterity. This initial inflammation and pain eventually subsides, and the patient is left with a permanent bony outgrowth that often skews the fingertip sideways. Bouchards nodes may also be present; these are similar bony growths in the proximal interphalangeal (PIP) joints (middle joints of the fingers), and are also associated with osteoarthritis. Heberdens nodes are more common in women than in men, and there seems to be a genetic component involved in predisposition to the condition. They are named after William Heberden (1710–1801). See also
Bouchards nodes Also present in martial artists, in particular judoka and Brazilian jiu-jitsu practitioners. References


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