Enzymatic hydrolysis of PTT polymers and oligomers.

Oligomers and polymers (film, fabrics) of the linear aromatic polyester poly(trimethylene terephthalate) (PTT) were treated with polyesterases from Thermomyces lanuginosus, Penicillium citrinum, Thermobifida fusca and Fusarium solani pisi. The cutinase from T. fusca was found to release the highest amounts of hydrolysis products from PTT materials and was able to open and hydrolyse a cyclic PTT dimer according to RP-HPLC-UV detection. In contrast, the lipase from T. lanuginosus also showed activity on the PTT fibres and on bis(3-hydroxypropyl) terephthalate (BHPT) but was not able to hydrolyse the polymer film, mono(3-hydroxypropyl) terephthalate (MHPT) nor the cyclic dimer of PTT. As control enzymes inhibited with mercury chloride were used. Surface hydrophilicity changes were investigated with contact angle measurements and the degree of crystallinity changes were determined with DSC.

Drug-induced headache: long-term follow-up of withdrawal therapy and persistence of drug misuse.

Patients suffering from migraine, tension-type headache (TTH), or combined headache (CH) are at risk of developing drug-induced headache (DIH) due to regular use of analgesics, ergot alkaloids, and triptans. The aim of our study was to determine (1) the clinical features of DIH, (2) the outcome of withdrawal therapy using high methodological standards, and (3) predictors which could explain the high relapse rate (more than 40%) after a previously successful withdrawal therapy. We retrospectively reviewed 103 patients with migraine or TTH who underwent withdrawal therapy between 1994 and 1998. The long-term follow-up (2-4 years after therapy) was conducted by phone and by specially trained psychologists using a structured interview which enclosed characteristics of headache and medication behavior as well as patients global assessment of success. Complete sets of data were available from 83 patients (38 migraine, 26 TTH, 19 CH). The most frequently abused drugs were caffeine-combined analgesics (24%), followed by caffeine-combined ergotamines (19%), pure ergot alkaloids (17%), and monoanalgesics (17%). 48.5% of the patients suffered an abuse relapse within 4 years and developed the complete features of DIH again. Analgesic and ergot alkaloid combinations with caffeine lead significantly more often to a relapse. A long-term successful therapy is connected with a significant reduction of the frequency of headache attacks. Under relapse conditions, the patients reached their former headache frequency level. The data show a higher relapse rate than previously assumed and that certain substance groups bear a higher relapse risk.