Effects of ascending buprenorphine doses on measures of experimental pain: A pilot study.

BACKGROUND: Buprenorphine is widely used in the treatment of opioid use disorder and pain management. Little is known about the analgesic effects of high-dose sublingual buprenorphine, particularly in doses of >8 mg. The aim of this study was to examine the effect of ascending doses of buprenorphine upon acute pain measures in patients stabilized on buprenorphine as treatment for opioid dependence. METHODS: The pilot study (n = 7) was a randomised, controlled, double-blind, double-dummy, within-subject crossover study examining cold-pressor threshold and tolerance testing under different buprenorphine dose conditions. Each participant attended three sessions to test the analgesic effect of buprenorphine in their usual dose (100%), 150% and 200% of their usual daily dose. RESULTS: No significant effects of increased dose were seen on experimental pain measures. Expected physiological effects on pupil size and pulse were observed with increasing dose. No effect of buprenorphine condition was seen on subjective ratings of drug strength, or self-reported sedation, though lower ratings drug liking were seen with 150% and 200% conditions, and lower ratings of 'bad effects' and intoxication were reported with the 200% buprenorphine dose condition. No safety concerns with the 150 and 200% buprenorphine dose condition were observed. DISCUSSION: This pilot study suggests that a ceiling effect on analgesia may be observed in people maintained on buprenorphine, though larger studies may confirm this finding. Clinical Trial Number: ACTRN12614001038684.

Blood flow of free gingival grafts measured by xenon-133 clearance.

Blood circulation of free gingival grafts by Xe-133 clearance was evaluated in this study with special attention to the relationship between the amount of circulation and graft thickness, surface area and contraction during the initial healing phase. Following baseline clinical examination and initial periodontal therapy, 32 patients received mucogingival surgery with free gingival grafts for treatment of insufficient attached gingiva. Blood flow in recipient and donor areas was measured by injection of Xe-133. Xenon clearance in the free gingival grafts was measured at the first, tenth, twentieth, and fortieth days. Mean blood flow was observed to decrease on the first day and then gradually increased at 10 and 20 days and finally reached the initial value of the recipient area on the fortieth day. It was observed that circulation in the grafted tissue was positively correlated with graft thickness, but negatively correlated with graft contraction during healing.

Bilateral globus pallidus lesions in a patient with Tourette syndrome and related disorders.

BACKGROUND: The neuroanatomic and pathologic basis of Tourette's syndrome or related disorders such as obsessive-compulsive disorder and attention deficit-hyperactivity disorder remains unknown. Although a substantial body of neuroimaging and other data implicate basal ganglia and some point out specifically the globus pallidus in the etiopathogenesis of these three related disorders, no clear or pathologically significant isolated lesions restricted to this region have yet been demonstrated, with the exception of obsessive-compulsive disorder. METHODS: A seventeen-year-old male case of Tourette syndrome with comorbid obsessive-compulsive disorder, attention deficit-hyperactivity disorder, stuttering and gait disturbance, who had negative family history is presented. RESULTS: The patient has failed to respond to drug treatment and his MRI scan revealed bilateral and symmetrical globus pallidus lesions with specific "tiger's eye" appearance of unknown etiology. CONCLUSIONS: Well-localized lesions in the globus pallidus support growing data suggesting the involvement of this brain region in Tourette syndrome and related disorders.