No abstract

HIV testing: changing trends SIR,-Dr E J Beck and colleagues (18 July, p 191) drew attention to steep increases in the number of requests from patients in London for tests for antibody to the human immunodeficiency virus (HIV) in October and November 1986 and March 1987, which coincided with the publicity campaigns associated with the government's educational programme about the acquired immune deficiency syndrome (AIDS). In Liverpool a similar trend was observed at the Public Health Laboratory, where these tests are performed on specimens submitted mainly from clinics for sexually transmitted diseases but also from hospital departments, drug dependency clinics, and general practitioners. The table shows the numbers of specimens for this test received monthly in the laboratory between May 1986 and June 1987, together with the number that were positive for antibody to HIV and the number of these that were from new patients. Sharp increases occurred in Liverpool at about the same time as in London, and, although, as in London, there was a pronounced fall in numbers from the peak in March 1987, the level maintained since then is much higher than that in the corresponding period in 1986. Though the proportion of patients who were found to be positive was much lower in Liverpool than in London, we also found that as the number of tests increased so the proportion that yielded positive results tended to decrease.

The aminopyrine breath test has been performed on Day 1 and Day 7 in pigs following experimental liver allografting. The results show that at 24 hr after surgery there was a significant reduction in liver function in all animals as measured by the elimination rate constant of 14CO2 in the breath. This was very profound in the group that died within 5 days (0.09 +/- 0.01 hr-1) and was significantly different from the group that survived (0.16 +/- 0.01 hr-1). There appears to be a critical value of the elimination rate constant (= 0.12 hr-1) which predicts death within 5 days. These results would justify a trial of the aminopyrine breath test in patients after liver transplantation.

Objective-To evaluate the effectiveness of arm traction for cervical spine imaging in trauma patients and devise a scheme to predict the probability of visualising the C7/T1 level in trauma patients. Methods-98 trauma patients were studied. Each vertebral body was divided into three equal horizontal zones, the disc space between vertebral bodies being equivalent to one zone. The fifth cervical vertebra was used as the starting level (zone 1). Zones obtained pre and post arm traction on the lateral cervical spine radiographs were recorded. Results were analysed to show the probability of imaging the lower cervical spine, including the cervico-thoracic junction. Results-If the initial film showed less than zone 10 (mid-C7 vertebra), the probability of showing zone 13 (upper body of Ti) with arm traction was only 7-7%, that is, one success in every 13 pulls; or conversely, 12 failures in every 13 pulls. Conclusions-Unless an initial cervical spine radiograph includes the upper one third of the body of the C7 vertebra, the probability of attaining the C7IT1 level with arm traction is < 15%. It is suggested that all initial radiographs of the lateral cervical spine in major trauma patients be done with arm traction, and where the upper one third of the body of C7 vertebra is not seen, then computerised tomography, swimmer's, or oblique views be considered.