Conversion syndrome

In view of the variety of possible immunological reactions directed towards the canaliculi or bile-duct epithelia and the difficulties involved in making a definitive histological diagnosis and classification, it would be feasible to include a so-called overlap syndrome or conversion syndrome in the hypothesis of autoimmune cholangitis. 

Conversion syndromes are also possible (1.) transition of PBC into AMA-negative PBC, then into ANA-posi-tive autoimmune hepatitis (AIH), (2.) transition of AIH into primary sclerosing cholangitis (PSC). 

In the presence of an overlap syndrome (or a conversion syndrome), the therapy concept depends on the respective predominant component, which as a rule is AIH. Consequently, prednisolone + UDCA or prednisolone + azathioprine + UDCA are applied. 

Fast-channel syndrome. The clinical features resemble those of autoimmune myasthenia gravis (see below) with variable severity. Conversely to what is found in slow-channel syndrome, the open state of the AChR is destabilized, manifesting as fast dissociation of ACh from the receptor and/or excessively reduced open times. One mutation has also caused multiple congenital joint contractures owing to fetal hypomotility in utero. In most cases, the mutant allele causing the kinetic abnormality... 

Opioids also interact with excitatory amino acid neurotransmitters. At lower micromolar concentrations, p agonists (e.g., DAMGO) enhance NMDA activity in the nucleus accumbens, but inhibit non-NMDA activity (Martin et al. 1997). At higher concentrations (5 pM), NMDA currents are reduced. Conversely, central administration of glutamate can precipitate a withdrawal syndrome in morphine-dependent animals, similar to the opioid antagonist naloxone. NMDA mechanisms also appear to be involved in the development of morphine tolerance. Competitive and noncompetitive NMDA antagonists and inhibitors of nitric oxide synthase reduce or eliminate tolerance to morphine (Elliott et al. 1995 Bilsky et al. 1996). However, this does not occur for tolerance to k opioids. Pharmacokinetics... 

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