Deep brain stimulation in addiction: a review of potential brain targets

Deep brain stimulation (DBS) is an adjustable, reversible, non-destructive neurosurgical intervention using implanted electrodes to deliver electrical pulses to areas in the brain. DBS is currently investigated in psychiatry for the treatment of refractory obsessive-compulsive disorder, Tourette syndrome and depressive disorder. Although recent research in both animals and humans has indicated that DBS may be an effective intervention for patients with treatment-refractory addiction, it is not yet entirely clear which brain areas should be targeted. The objective of this review is to provide a systematic overview of the published literature on DBS and addiction and outline the most promising target areas using efficacy and adverse event data from both preclinical and clinical studies. We found 7 animal studies targeting six different brain areas: nucleus accumbens (NAc), subthalamic nucleus (STN), dorsal striatum, lateral habenula, medial prefrontal cortex (mPFC) and hypothalamus, and 11 human studies targeting two different target areas: NAc and STN. Our analysis of the literature suggests that the NAc is currently the most promising DBS target area for patients with treatment-refractory addiction. The mPFC is another promising target, but needs further exploration to establish its suitability for clinical purposes. We conclude the review with a discussion on translational issues in DBS research, medical ethical considerations and recommendations for clinical trials with DBS in patients with addiction.

Isolation and characterization of porcine circovirus type 2 from pigs showing signs of post-weaning multisystemic wasting syndrome in The Netherlands

Pigs with wasting syndrome were examined for macroscopic and histopathological lesions, and for porcine circovirus (PCV). Histopathological lesions were comparable to those previously documented for post-weaning multisystemic wasting syndrome (PMWS). In addition, in seven out of ten examined PMWS-affected pigs focal-to-slight mononuclear meningitis and focal cerebral mononuclear infiltrates (4 out of 10) were observed. A virus was isolated from organs and sera from pigs showing wasting syndrome. An immunoperoxidase monolayer assay and an indirect immunofluorescence assay were performed on the infected PK-15 and Dulac cell cultures, respectively, and both assays indicated the presence of PCV type 2 (PCV2). The nested-polymerase chain reaction (nPCR) technique, based on the use of PCV2 specific oligonucleotides, revealed specific amplified products of 481 bp. Nucleotide sequence analysis of the entire genome of the Dutch PCV isolate 24657 NL showed a homology with known nucleotide sequences of porcine PCV type 1 (PCV1) and PCV2 isolates of 77.1% and >96%, respectively. This is the first report of the isolation and characterization of PCV2 in PMWS-affected pigs in the Netherlands.

[Delayed parturition in sheep by clenbuterol (author's transl)]

The effect of treatment with clenbuterol on lambing during the period from 9 p.m. to 5 a.m. was studied in a field trial in sheep, which was continued for twenty-two days. The date of tupping was not known. The sheep were divided into an experimental and a control group, each numbering 106 animals. Animals of the experimental group were assessed every day at approximately 7.30 p.m., using a system of scoring for the development of udders and vulvae, and were treated with oral administration of 200 micrograms of clenbuterol when the findings suggested that parturition would occur that night. Seventy-nine animals of the experimental group lambed. twelve of them lambing during the night (two of these had been treated in the evening before lambing); of the group of controls, seventy-two lambed, twenty-three doing so during the night (difference significant: P greater than 0.05). The difference in the number of lambings during the night between treated and untreated animals was highly significant (P less than 0.001). Side-effects of clenbuterol were not recorded. The amount of clenbuterol used in the group of controls was: 3.49 tablets/lambing sheep, 5.03 tablets/treated sheep and 5.02 tables/treated and lambing sheep. This high consumption rate is attributed to the fact that the date of tupping was not known as well as to the defectiveness of the criteria on which the decision to treat or not to treat was based.