The pattern evoked response in disorders of the optic nerve

The pattern evoked electroretinogram (PERG) was investigated in 11 patients with unilateral optic nerve disease and in a series of age-matched controls. The visually evoked potential (VEP) was also measured. The PERG showed a similar reduction to the VEP in optic nerve disease. Serial studies indicate that the PERG may not be affected immediately in some instances but may show a gradual decline over several months.     

Respiratory health status in swine producers using respiratory protective devices

A cross-sectional survey on respiratory health in swine producers showed that 30% of 301 examined men usually used a dust mask when working inside a barn. They did not differ significantly from dust mask nonusers in respect to respiratory symptoms and lung function. This analysis was undertaken to determine whether the respiratory health of dust mask users was associated with reasons why they had started individual respiratory protection. The subjects were recontacted in order to identify those who started using a mask to deliberately prevent symptoms (42 men) and those who started protection because of pre-existing respiratory symptoms (44 men). Not unexpectedly, betweengroup comparisons of respiratory symptoms and lung function suggest that swine producers who wear dust masks for preventive purposes have better respiratory health than those who wear dust masks because of symptoms or those who do not use individual respiratory protection. The individual reasons for starting dust mask usage should be examined among potential determinants of the outcomes of prospective studies which can then provide more valid assessment of the effect of individual respiratory protection. © 1993 Wiley-Liss, Inc.     

Time taken to produce dispensing labels in hospital pharmacies,and factors affecting it

The time taken in hospital pharmacies to produce labels for individual patients' medication was measured, and factors affecting the labelling process investigated. Labelling time was measured by direct observation using a stopclock at randomly chosen semi-stratified time periods. Four combinations of major London hospitals and computer systems were studied. The time to produce 2,167 labels was measured and 59 operators were observed. There were significant differences in average labelling time between the studied hospitals/systems (16.6 to 39.3 seconds per label). Operators' experience with their system and the occurrence of interruptions were found to affect labelling significantly (P<0.0001 in both cases). There was an overall trend for labelling time to decrease with increasing experience (P<0.0001), and interruptions added 11 to 12 seconds on average. Operator experience also affected the rate and duration of interruptions, which subsequently affected labelling time. Fewer interruptions occurred with more experienced staff (P=0.0015) and when interrupted, they took less time than inexperienced staff to complete the labelling process. A performance indicator of person-days per 100,000 labels varied from 62.3 to 147.6. Pharmacy managers should be aware that there are significant differences in performance using different labelling systems and that staff training and systems of work may have a marked effect on labelling time.     

Using a dense PTFE membrane without primary closure to achieve bone and tissue regeneration.

The most common types of barrier membranes used for bone or tissue regeneration are made of expanded-polytetrafluoroethylene (e-PTFE) or resorbable materials, such as collagen. Both the e-PTFE and resorbable membranes require primary soft tissue coverage. This article explores the use of a dense-polytetrafluoroethylene (d-PTFE) membrane, which does not require primary soft tissue coverage. The advantages of d-PTFE in contrast to the other more commonly used types of barrier membranes and the clinical significance of these advantages for implant surgical and restorative treatment are discussed.     

A phospholipid spin label used as a liposome-associated MRI contrast agent

Given current clinical use of phospholipid bilayer structures (liposomes/vesicles) as nontoxic drug delivery vehicles, we have addressed the possibility of employing the phospholipids themselves as MRI contrast agents. To this end we have synthesized phosphatidylcholine with a nitroxide spin label replacing one methyl residue of the choline headgroup. This material was mixed with natural phosphatidylcholine in mole ratios from 1:50 to 1:1 and used to prepare sonicated unilamellar vesicles in saline. Expected structural features of these vesicles were verified by freeze-fracture electron microscopy. Proton T1 values of saline were readily decreased to less than 0.3 s by such preparations, yielding a net relaxivity of 0.6 M-1 s-1. The approach seems to be a realistic way of firmly associating a contrast agent of minimal toxicity with ordinary liposomes/vesicles in a manner that is not subject to leakage.