Anatomically specific patterns of glial activation in the periaqueductal gray of the sub-population of rats showing pain and disability following chronic constriction injury of the sciatic nerve.

Neuropathic pain conditions for which treatment is sought are characterized by complex behavioural disturbances, as well as "pain." Recent studies using chronic constriction injury of the sciatic nerve have shown that rats develop three distinct patterns of disability characterized by changes in social-interactions and sleep-wake cycle behaviours post-injury: (i) Persistent Disability, (ii) Transient Disability and (iii) No Disability. These patterns occur despite all rats showing identical levels of allodynia and hyperalgesia (i.e., pain). In rats, social-interactions and sleep-wake cycle behaviours are regulated in part, by neural networks, which converge on the periaqueductal grey (PAG). We sought therefore to identify neural adaptations in the PAG, 6 days following chronic constriction injury (CCI), the time at which rats in which disabilities persist are first distinguished from those without disabilities (i.e., No Disability and Transient Disability). GeneChips, RT-PCR and Western blotting revealed the select up-regulation in translation and transcription of glial fibrillary acidic protein (GFAP) and Vimentin in rats with Persistent Disability. Significant increases in GFAP immunoreactivity were localized histologically to the lateral and caudal ventrolateral columns of the PAG. This anatomically specific pattern of increased GFAP suggests activation of astrocytes by select neural pathways, which likely include afferents of both spinal and nucleus of the solitary tract (NTS) origin. The PAG columns in which astrocytes are activated play significant roles in modulating both social-interactions and the sleep-wake cycle. It is possible therefore that the persistent disabilities seen in a subgroup of CCI rats are in part a functional consequence of this specific pattern of astrocyte activation.

Cardiovascular responses and anaerobic threshold for bicycle and arm ergometer exercise.

Cardiovascular responses occurring at the anaerobic threshold (AT) were compared during intermittent bicycle and arm ergometry in eight healthy college students. Arm and bicycle tests used time-matched, discontinuous protocols (three-minute work stages alternated with three-minute rest intervals). Anaerobic threshold was determined by plotting expired minute volume (Ve) on oxygen consumption (VO2) and expressed as the percentage of the respective peak VO2 at which the deflection occurred. Analysis of variance revealed AT was similar for arm and bicycle tests. Absolute VO2 at AT was higher for bicycle than for arm ergometer exercise (p less than .05). Heart rate (HR) and rate pressure product (RPP) were higher for bicycle than for arm ergometry at AT (p less than .05). Moreover, a similarity in percent maximum RPP and percent maximum VO2 was observed at AT for arm ergometry, whereas percent maximum RPP was higher than percent maximum VO2 at AT for bicycle ergometry. Because AT has been suggested as an appropriate intensity of exercise for conditioning, it was concluded that a sufficient level of exercise intensity can be elicited at a lower percentage of the cardiovascular reserve for arm than for bicycle ergometer exercise.

Sonographically guided percutaneous aspiration of intra abdominal - abstract

Percutaneous sonographically-guided drainage (PSGD) of intra-abdominal fluid collections is a relatively new techniqe which can often achieve the results of open surgery without having to take the patient through a major operative procedure. Eighteen consecutive cases treated by this technique are presented. There were 12 liver abscesses, 3 paracolic abscesses and 3 renal cysts. One abscess recurred and was successfully treated by repeat PSGD. One patient died from preceding overwhelming sepsis which persisted 4 hours after PSGD. In no case was there any evidence of spread of infection or other complications of PSGD. Because many patients with intra-abdominal abscesses are very ill, the additional morbidity of open surgery can be avoided by using PSGD. Our success with this technique suggest that it should be more widely used throughout the region wherever appropriate ultrasonography is available (AU)