Provoked asthma and mast cells

There is now very substantial evidence to implicate mediators in the pathogenesis of asthma during both the early- and late-phase response. It seems likely that mast cells are activated since histamine was detected in early- and late-phase allergen- and exercise-induced asthma. On the other hand, the origin of NCA is still in some doubt, and the possibility exists that it may be derived from other cell types. Furthermore, there is no firm evidence that the mast cell is directly involved in pathogenesis and some evidence that it may have a secondary or amplifying role. There is an urgent need for further details of other mast-cell-associated mediators such as prostaglandins and leukotrienes. Measurements in the blood have the obvious disadvantage of only indirectly reflecting events in the lung. It seems likely that more invasive procedures such as fiberoptic bronchoscopy will yield more critical information regarding mast cells and their mediators in early- and late-phase reactions, as well as the effects of selective drugs and the role of other cell types.     

Comparison of the Effectiveness of Two Bowel Programs for CVA Patients

The purpose of the study described in this article was to compare the effectiveness of two bowel training programs for patients who had experienced a cerebrovascular accident (CVA) and to determine the length of time required to establish a regulated program. A quasi-experimental design was used to compare the existing bowel program that incorporated every-other-day digital stimulation (DS) with a program using daily DS. The convenience sample of 48 CVA patients included 23 in the control group who had DS every other day and 25 in the experimental group who had daily DS. Demographic data showed no significant differences between the two groups. The t-test showed that more subjects in the experimental group established regularity; however, the subjects in the control group who did achieve regularity took less time to do it. Subjects with right-side hemiplegia and less mobility required more time to become established. As a result of these findings, the routine protocol for bowel training in this rehabilitation unit has been changed to include daily digital stimulation.     

Accommodative hysteresis under static and dynamic stimulus conditions

The influence of continuous variation in dioptric demand on the accommodative hysteresis induced at near distances was examined in 14 visually-normal young adults. Tonic accommodation was measured before and after 10 minutes of sustained focus using a constant stimulus at 5 D, 6.5 D, and 8 D, as well as a stimulus which slowly and alternately increased and decreased over the continuous range from 5 D to 8 D. For approximately half the subjects, dioptric demand had to be very high (8 D) under static conditions to produce moderate but significant hysteresis, yet little or no attenuation of the effect occurred under the dynamic condition. For other subjects who consistently showed very large tonic changes (1.4 D or more) under static conditions, the hysteresis effect generated under dynamic conditions was greatly reduced (approximately 50 per cent) in magnitude. These findings suggest that the degree to which continuous variation in dioptric demand will disrupt the adaptive process may depend on individual differences in the rate and/or maximum level of tonic accommodative change. Such a relationship could have bearing on the particular strategy recommended for individuals who tend to experience blur at distance following nearwork.     

Effect of different questionnaire formats on reporting of occupational exposures

During an exposure monitoring study, 78 saw maintenance tradesmen were randomly assigned to be interviewed about their exposures using one of two questionnaire formats: open-ended and partly prompted questions about five categories of materials; and detailed prompting about 75 agents. The more open-ended questionnaire elicited fewer exposure responses overall, but more responses about agents not included on the detailed questionnaire. Composite materials and trade name products were more frequently cited as exposures than individual metals or compounds. Validity of responses was ascertained using air measurements (individual metals) or observations of the employees (composite materials). Sums of sensitivities and specificities were very low (near 1.0) for most of the metals for both types of questionnaire. For composite materials, validity improved substantially. Sensitivities with the partly prompted format (0.44–0.85) were always lower than with detailed prompting (0.80–1.00). Specificities were usually, but not always, higher with partial prompting (0.66–0.92) than with detailed prompting (0.18–0.86). Selection of questionnaire format for an epidemiologic study would depend on the likely prevalence of exposure in controls and the effects of trade-offs in sensitivity and specificity.     

Intravenous anaesthesia for cystoscopy: a comparison of propofol or methohexitone with alfentanil

Sixty out-patients undergoing cystoscopy were allocated randomly into two groups. No premedication was given. Induction of anaesthesia was preceded by intravenous alfentanil 7 micrograms kg-1 given over 20 s, followed by methohexitone 1.5-2 mg kg-1 or propofol 2 mg kg-1, given over 20 s. Anaesthesia was maintained by increments of alfentanil, methohexitone or propofol, given as required.