Deep brain stimulation (DBS) is currently tested as an experimental therapy for patients with treatment-resistant depression (TRD). Here we report on the short- and long-term (1 yr) clinical outcomes and tolerance of DBS in eight TRD patients. Electrodes were implanted bilaterally in the subgenual cingulate gyrus (SCG; Broadman areas 24-25), and stimulated at 135 Hz (90-μs pulsewidth). Voltage and active electrode contacts were adjusted to maximize short-term responses. Clinical assessments included the 17-item Hamilton Depression Rating Scale (HAMD17; primary measure), the Montgomery-Åsberg Depression Rating Scale (MADRS) and the Clinical Global Impression (CGI) Scale. In the first week after surgery, response and remission (HAMD ⩽7) rates were, respectively 87.5% and 50%. These early responses were followed by an overall worsening, with a response and remission rates of 37.5% (3/8) at 1 month. From then onwards, patients showed a progressive improvement, with response and remission rates of 87.5% and 37.5%, respectively, at 6 months. The corresponding figures at 1 yr were 62.5% and 50%, respectively. Clinical effects were seen in all HAMD subscales without a significant incidence of side-effects. Surgical procedure and post-operative period were well-tolerated for all patients. This is the second independent study on the use of DBS of the SCG to treat chronic depression resistant to current therapeutic strategies. DBS fully remitted 50% of the patients at 1 yr, supporting its validity as a new therapeutic strategy for TRD.

Samples of poly(syndiotactic styrene-co-butadiene) (sPS-B) have been prepared using methylalumoxane (MAO) activated CpTiCl3 under a range of experimental conditions. Copolymerization activities were low (24-36 kg mol -1 of cat. h -1 ) and nearly constant over the range of polymerization temperatures investigated (25-70 °C). Eight sPS-B samples were synthesized at 25 °C with styrene molar fractions (xs) covering a full range of compositions (xs ) 0.15-0.92). The copolymer samples were characterized by solution and solid state 13 C NMR spectroscopy, X-ray powder diffraction analysis, and thermal (DSC) analysis. The 13 C NMR analysis of the copolymer microstructure suggests that the butadiene homosequences are primarily cis-1,4 and the styrene segments are syndiotactic. However, some 1,2-and trans-1,4-butadiene units are occasionally formed during the polymerization process. The 13 C NMR resonances diagnostic of the monomer triads comprising styrene units (SSB, SBS, BBS, BSB, and SSS) were assigned and the average styrene block lengths (nS) calculated. Copolymer samples in which nS > 9 are crystalline due to the syndiotactic polystyrene segments detected in the δ-toluene clathrate form with melting points in the range 205-230 °C. Syndiotactic polystyrene segments with shorter styrene block lengths are amorphous and partially included in the poly(butadiene) rubber domains. TEM images of sample 13 (xS ) 0.37, nS ) 8.8) show the presence of small sPS fibers.