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.     

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.      

The CTLA-4 gene region of chromosome 2q33 is linked to, and associated with, type 1 diabetes. Belgian Diabetes Registry

Susceptibility to autoimmune insulin-dependent (type 1) diabetes mellitus is determined by a combination of environmental and genetic factors, which include variation in MHC genes on chromosome 6p21 (IDDM1) and the insulin gene on chromosome 11p15 (IDDM2). However, linkage to IDDM1 and IDDM2 cannot explain the clustering of type 1 diabetes in families, and a role for other genes is inferred. In the present report we describe linkage and association of type 1 diabetes to the CTLA-4 gene (cytotoxic T lymphocyte associated-4) on chromosome 2q33 (designated IDDM12). CTLA-4 is a strong candidate gene for T cell- mediated autoimmune disease because it encodes a T cell receptor that mediates T cell apoptosis and is a vital negative regulator of T cell activation. In addition, we provide supporting evidence that CTLA-4 is associated with susceptibility to Graves' disease, another organ- specific autoimmune disease.      

Outcomes of gastrostomy placement with and without concomitant tracheostomy among ventilator dependent children

IntroductionSimultaneous gastrostomy tube (GT) and tracheostomy placement in young children offers potential benefit in limiting anesthetic exposure, but it is unknown whether combining these procedures introduces additional morbidity. This study compared outcomes after combined GT and tracheostomy placement versus GT placement alone among similar ventilator-dependent patients.MethodsVentilator-dependent children <2-years-old who underwent GT placement alone (MV-GT), simultaneous GT and tracheostomy placement (GT+T), and GT placement alone with a pre-existing tracheostomy (T-GT) were identified using 2012–2018 NSQIP-Pediatric Participant User Files. Multiple logistic regression models were used to compare outcomes while adjusting for other group differences.ResultsAmong 1100 children, 351 underwent MV-GT, 494 GT+T, and 255 T-GT. Major complications occurred in 23.6%, 17.0%, and 14.5% of the respective groups (p = 0.01). Major complications with GT+T were similar to T-GT (adjusted odds ratio [aOR]=1.19, 95%CI:0.78–1.83, p = 0.4) and lower than MV-GT (aOR=0.67, 95%CI:0.47–0.95, p = 0.02). Severe complications including mortality, cardiac arrest, and stroke were similar between the three groups (p = 0.8).ConclusionsChildren <2-years-old undergoing GT+T did not experience higher post-operative complications compared to children undergoing T-GT or MV-GT. Utilizing GT+T to limit anesthetic exposure may be reasonable within this high-risk population.Type of StudyTreatment StudyLevel of EvidenceLevel III     

The costs and effects of a nutritional education program following work-site cholesterol screening.

OBJECTIVES. The purpose of this study was to assess the costs and impact of a nutrition education program following a cholesterol screening. METHODS. Forty work-sites were randomly assigned to one of two educational interventions: a "usual" intervention of 5 minutes of counseling, or a "special" intervention of 2 hours of behaviorally based education on dietary changes to lower serum cholesterol. Costs were monitored, and cholesterol levels were retested 6 and 12 months later. RESULTS. The total per-person cost for screening and the educational intervention was about $50. Cholesterol levels differed little between the two intervention groups 6 months after screening, but after 12 months those in the special intervention worksites showed a 6.5% drop in cholesterol, whereas those at the usual intervention worksites showed a drop of only 3.0%. Hence a 3.5% cholesterol reduction was attributable to the special intervention. CONCLUSIONS. A behaviorally based nutrition education program following cholesterol screening can have a meaningful impact on long-term cholesterol levels at a low cost. Nutrition education in work-sites may therefore be a useful way to lower the risk of heart disease in communities.     

The vasa vasorum and angioplasty

Interruption of flow in the vasa vasorum may lead to medial necrosis and aneurysm formation. The purpose of this study was to determine whether angioplasty produces significant alterations in the morphology or blood flow of the vasa vasorum of the dilated artery. The morphology of the canine vasa vasorum was studied before and after angioplasty; in a separate experiment vessel wall blood flow (VWBF) in canine carotid arteries was measured after angioplasty to determine whether physiologic regulation of the blood flow was disrupted by arterial dilation. No morphologic changes could be demonstrated in the vasa vasorum of the dilated artery; however, VWBF was increased by 1194 +/- 215% (mean +/- standard error, p less than 0.01) between 90 and 120 minutes after angioplasty. VWBF in the adjacent nondilated arterial segment was also increased (720 +/- 177% between 10-30 minutes, p less than 0.01) but returned toward normal after 60 minutes. Adenosine caused a "paradoxical" decrease in VWBF (p less than 0.05) of the dilated arterial segment while causing increased VWBF (p less than 0.05) in the thoracic aorta. Angioplasty appears to produce persistent hyperemia in the dilated arterial wall. A paradoxical response to adenosine suggests that vasa vasorum in the dilated arterial segment are maximally vasodilated. This may be due to mechanical disruption of vasomotor tone or to release of vasoactive substances.