Blur adaptation: clinical and refractive considerations

The human visual system is amenable to a number of adaptive processes; one such process, or collection of processes, is the adaptation to blur. Blur adaptation can be observed as an improvement in vision under degraded conditions, and these changes occur relatively rapidly following exposure to blur. The potential important future directions of this research area and the clinical implications of blur adaptation are discussed.     

Daily changes in presynaptic cholinergic activity of rat sympathetic superior cervical ganglion

The in vitro capacity of sympathetic superior cervical ganglia (SCG) to take up [³H]choline from the extracellular medium, to synthesize acetylcholine from [³H]choline, and to release [³H]acetylcholine in response to a high K⁺ concentration, were examined in rats throughout a 24-h cycle. Both the release of [³H]acetylcholine and the synthesis of [³H]acetylcholine from [³H]choline exhibited significant diurnal variations, showing maxima during the first half of the night. After these maxima, nocturnal acetylcholine release and synthesis decayed to daytime levels and remained low until the end of the night. [³H]Choline uptake by rat SCG did not vary significantly throughout a 24-h period. A 1.5-h exposure of rats to darkness at the 5th hour of light phase of the daily photoperiod did not change significantly any parameter studied. A 20-min, 5-Hz, electrical stimulation of the preganglionic trunk of SCG excised from rats at noon increased significantly subsequent K⁺-induced [³H]acetylcholine release but did not change [³H]acetylcholine synthesis. In decentralized SCG of rats subjected to a unilateral SCG decentralization and a contralateral sham-operation 7 days earlier, [³H]acetylcholine release and synthesis were highly reduced or abolished at the decentralized side, while [³H]choline uptake remained unaltered. The present results suggest that an activation of preganglionic rat SCG neurons takes place during the first half of the scotophase.     

Serum ionic fluoride levels in haemodialysis and continuous ambulatory peritoneal dialysis patients

High serum fluoride (F-) in patients with chronic renal failure (CRF) and end-stage renal disease (ESRD) is associated with risk of renal osteodystrophy and other bone changes. This study was done to determine F- in normal healthy controls and patients with ESRD on haemodialysis (HD) or peritoneal dialysis (PD). Seventeen healthy controls (12 males, 5 females) and 39 ESRD patients on dialysis (17 males, 22 females) were recruited in the study in a community with 47.4 +/- 3.28 microM/l (range 44-51 microM/l) of F- content in drinking water. Control subjects showed a mean serum F- concentration of 1.08 +/- 0.350 microM/l. Males in control group showed slightly higher F- levels (1.15 +/- 0.334, range 0.55-1.9 microM/l) than females (0.92 +/- 0.370, range 0.6-1.5 microM/l). Mean serum F- concentration did not correlate significantly with age and sex among control subjects, whereas such correlation was observed in patients with ESRD on dialysis. Mean serum F- concentration was significantly higher in patients on dialysis (2.67 +/- 1.09, range 0.8-5.2 microM/l) than normal controls. When grouped according to sex, the mean serum F- concentration in males (3.05 +/- 1.04, range 1.8-5.2 microM/l) was significantly higher than females (2.38 +/- 1.08, range 0.8-5.2 microM/l). When patients were grouped according to age, it was observed that F- concentration was significantly higher in patients with age groups 21-70 (2.86 +/- 1.05) than those with age group 13-20 years (1.42 +/- 0.531). Thus F- concentration correlated with age and sex, being higher in males and above 20 years. Despite appreciable clearance of F- (39-90%) across the peritoneum, patients on CAPD showed higher serum F- concentration than those on HD (3.1 +/- 1.97 vs 2.5 +/- 1.137 microM/l). Of the total 39 patients on dialysis 39% had their serum F- concentration above 3.0 microM/l, posing the risk of renal osteodystrophy.      

Evaluation of the culture of safety: survey of clinicians and managers in an academic medical center

Background: Despite the emphasis on patient safety in health care, few organizations have evaluated the extent to which safety is a strategic priority or their culture supports patient safety. In response to the Institute of Medicine's report and to an organizational commitment to patient safety, we conducted a systematic assessment of safety at the Johns Hopkins Hospital (JHH) and, from this, developed a strategic plan to improve safety. The specific aims of this study were to evaluate the extent to which the culture supports patient safety at JHH and the extent to which safety is a strategic priority.

Methods: During July and August 2001 we implemented two surveys in disparate populations to assess patient safety. The Safety Climate Scale (SCS) was administered to a sample of physicians, nurses, pharmacists, and other ICU staff. SCS assesses perceptions of a strong and proactive organizational commitment to patient safety. The second survey instrument, called Strategies for Leadership (SLS), evaluated the extent to which safety was a strategic priority for the organization. This survey was administered to clinical and administrative leaders.

Results: We received 395 completed SCS surveys from 82% of the departments and 86% of the nursing units. Staff perceived that supervisors had a greater commitment to safety than senior leaders. Nurses had higher scores than physicians for perceptions of safety. Twenty three completed SLS surveys were received from 77% of the JHH Patient Safety Committee members and 50% of the JHH Management Committee members. Management Committee responses were more positive than Patient Safety Committee, indicating that management perceived safety efforts to be further developed. Strategic planning received the lowest scores from both committees.

Conclusions: We believe this is one of the first large scale efforts to measure institutional culture of safety and then design improvements in health care. The survey results suggest that strategic planning of patient safety needs enhancement. Several efforts to improve our culture of safety were initiated based on these results, which should lead to measurable improvements in patient safety.

     

Ciprofloxacin-induced renal insufficiency in cystic fibrosis.

Acute renal insufficiency is known to occur in patients who are taking ciprofloxacin, particularly the elderly. We report two young patients with cystic fibrosis who presented with acute renal insufficiency after 2-3 weeks of oral ciprofloxacin therapy. The incidence of this adverse effect in children and young adults who have cystic fibrosis is unknown. Multiple mechanisms for ciprofloxacin-induced nephrotoxicity have been proposed.