Evaluation of Using Behavioural Changes to Assess Post-Operative Pain in the Guinea Pig (Cavia porcellus).

To manage pain effectively in people and animals, it is essential to recognise when pain is present and to assess its intensity. Currently there is very little information regarding the signs of post-surgical pain or its management in guinea pigs. Studies from other rodent species indicate that behaviour-based scoring systems can be used successfully to detect pain and evaluate analgesic efficacy. This preliminary study aimed to establish whether behaviour-based scoring systems could be developed to assess post-surgical pain in guinea pigs. This prospective, randomised, placebo-controlled study used 16 guinea pigs, and evaluated changes in behaviour following either anaesthesia alone or anaesthesia and orchiectomy. Behaviour was assessed using a combination of manual and automated scoring of remotely obtained video footage. A small number of behaviours were identified that appeared to have high specificity for pain caused by orchiectomy. However, the behaviours were displayed infrequently. The most common was a change in posture from standing to recumbency, sometimes with one hind leg extended either to the side or behind the body. A composite behaviour score incorporating these abnormal behaviours differentiated between the effects of surgery and anaesthesia alone (p<0.0001), and between animals that received analgesia post-operatively compared to an untreated group (p<0.0001). Although behavioural changes occurred in these guinea pigs after orchiectomy, the changes were relatively subtle and the individual specific pain-related behaviours occurred infrequently. However, it may prove possible to develop a behaviour-based scoring system for routine use in this species using a combination of pain-related behaviours.

The use of propofol and sevoflurane for surgical anaesthesia in New Zealand White rabbits.

New Zealand White (NZW) rabbits (n = 34) received intravenous propofol (16 +/- 5 mg/kg) for induction of anaesthesia followed by maintenance with sevoflurane (4.0 +/- 0.5%) in oxygen. All animals underwent ovariohysterectomy. Heart rate, respiratory rate, haemoglobin oxygen saturation, end-tidal carbon dioxide concentration, end-tidal sevoflurane concentration and oesophageal temperature were monitored every 5 min. Time from induction of anaesthesia to tracheal extubation and sternal recumbency were recorded as was the quality of recovery. Direct arterial blood pressure values (mmHg) were recorded every 5 min from 19 rabbits and 22 arterial blood gases analyses were performed (11 postintubation and 11 at the time of recovery). Propofol produced smooth induction of anaesthesia without production of apnoea. Intubation was successfully performed in all but one rabbit in an average of 4 +/- 3 min from the beginning of propofol administration. No ventilatory support was required during the anaesthetic period. Respiratory rate averaged 51 +/- 8 bpm and end-tidal CO(2) (kPa) was 4.0 +/- 0.5 mmHg during anaesthesia. Blood gas values were maintained within normal limits and average mean arterial blood pressure was 73.4 +/- 7.9 mmHg. Time to regain the swallowing reflex following discontinuation of sevoflurane was 2 +/- 1 min and time to sternal recumbency was 8 +/- 0.3 min. No anaesthetic-related mortality occurred and all animals recovered uneventfully. Propofol-sevoflurane anaesthesia produced a good quality of surgical anaesthesia for ovariohysterectomy and stable cardiopulmonary conditions. Propofol-sevoflurane anaesthesia in young healthy NZW rabbits appears to be an effective and practically useful method of anaesthesia.

Characterisation of airborne particles collected within and proximal to an opencast coalmine: South Wales, U.K.

Airborne particulate matter has been collected from within, and proximal to, an opencast coal mine in south Wales. This work forms the first part of a three year project to collect and characterise, then determine the possible toxicology of airborne particles in the south Wales region. High-resolution Field Emission SEM has shown that the coal mine dusts consist largely of an assemblage of mineral grains and vehicle exhaust particles. SEM-EDX has shown that the mineralogical make-up of the PM10 is complex, heterogeneous, and constantly changing. These findings are supported by analytical TEM-EPXMA. However, patterns can be determined relating the mineralogical composition of the airborne particles to collection locations and mining activities within the opencast. At our study opencast, Park Slip West, quartz, which has known health effects, never exceeded 30% of the total collection mass, and average levels were much less. Vehicle exhaust emissions was the largest source in terms of particle numbers. The mass of airborne particulate matter within the pit averaged approximately twice that of outside the pit: importantly however, this higher mass was due to relatively large, and non-respirable, mineral grains. This study demonstrates that the physicochemical and mineralogical characterisation of airborne particles from mining and quarrying is essential to quantify the respirable fraction, and to identify potentially hazardous components within the PM10.