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.     

Pattern electroretinography and visual evoked potentials in optic nerve diseases.

BACKGROUND: To evaluate transient pattern electroretinography (PERG) and pattern visual evoked potential (VEP) for the diagnosis, differential diagnosis and follow-up of optic nerve diseases. METHODS: Twenty-nine consecutive patients (14 female, 15 male) with the diagnosis of ischaemic optic neuropathy (n=14) and optic neuritis (n=15) were included in this study. Mean age of the patients with ischaemic optic neuropathy was 63.3+/-3.3 (60-78) years and the mean age of the patients with optic neuritis was 28.3+/-8.4 (19-43) years. In each patient ophthalmological examination and systemic evaluation were done and VEP and PERG were recorded. As a control group, VEP recordings of 35 healthy subjects were included. RESULTS: In the ischaemic optic neuropathy group (group 1), mean VEP amplitude (+/-SD) (1.96+/-0.95 microV) was found to be decreased significantly in the affected eyes in comparison to the control group and the unaffected eyes. The delay in latency (116.3+/-20.14 msec in the affected eyes compared with 101.31+/-6.19 msec in unaffected eyes) was statistically significant when compared with the healthy subjects. In the optic neuritis group (group 2), VEP amplitude was decreased (4.13+/-4.04 microV vs 6.97+/-3.35 microV and 6.97+/-4.43 microV) and latency was increased (122.59+/-20.09 msec vs 101.31+/-6.19 msec and 108.76+/-13.57 msec) in affected eyes significantly in comparison to the unaffected eyes and control group, respectively. Even though there were no significant differences for P50 latency and N95/P50 ratios between affected and unaffected eyes in both groups, N95 amplitude decreased significantly in the affected eyes of the ischaemic optic neuropathy patients and N95 latency was found to be decreased in optic neuritis patients. There was no correlation between VEP and PERG findings in both groups. CONCLUSION: VEP amplitude decreased significantly in ischaemic optic neuropathies while latency delay was more significant in patients with optic neuritis. PERG findings showed decreased N95 amplitude in ischemic optic neuropathy without associated latency changes.     

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.      

Adiponectin levels and atherosclerotic risk factors in pediatric chronic peritoneal dialysis patients.

BACKGROUND: Atherosclerotic vascular diseases are the major cause of mortality in patients with end-stage renal disease (ESRD) treated with chronic peritoneal dialysis (CPD), even in children. Adiponectin (ADPN) is a recently discovered adipocyte-derived plasma protein having anti-atherogenic properties. ADPN levels are elevated in ESRD but it has been reported that ESRD patients with low plasma ADPN levels have a high risk of cardiovascular death. OBJECTIVE: To clarify the atherosclerotic risk and especially the significance of ADPN levels in pediatric patients on CPD. DESIGN: Cross-sectional studyin the pediatric peritoneal dialysis unit of a university hospital. PATIENTS: 18 children, aged 12.6 +/- 5.6 years, being treated with CPD and 20 healthy age- and sex-matched control subjects were enrolled in this study. METHODS: Serum ADPN levels and other risk factors, including blood pressure, blood glucose, serum lipid/lipoprotein fractions, apolipoprotein B, C-reactive protein (CRP), lipoprotein(a), and homocysteine levels, were studied in CPD patients and compared to the controls. RESULTS: Serum ADPN levels were three times higher in the CPD group compared to the control subjects, as was previously reported. Apolipoprotein B and CRP levels were also high in the CPD group. No significant difference was found in other atherosclerotic parameters, including lipoprotein(a) and homocysteine levels. Interestingly, we found a negative correlation between log ADPN and creatinine levels among the CPD patients (r = -0.54, p < 0.05). There was no correlation between log ADPN and duration of CPD. Creatinine and low-density lipoprotein levels could account for 54% of the total variation in ADPN levels. CONCLUSION: Among pediatric CPD patients, serum levels of the anti-atherogenic protein, ADPN, were inversely associated with creatinine. ADPN level might be a novel marker to predict prognosis in pediatric CPD patients.     

Relation of the radial nerve with the sulcus nervi radialis: a morphometric study

The radial nerve's course from the axillary region, branch patterns and the relation of the nerve to fixed anatomical landmarks in the arm region were studied in 27 embalmed intact cadavers. The radial nerve and its relation with the sulcus nervus radialis (SNR) was analyzed. The direct contact of the nerve with humerus in SNR was observed during the dissections. The following measurements were made: the total length of the humerus (the palpable uppermost point of the tuberculum majus and the lateral epicondyle); proximal safe zone (the tuberculum majus and the proximal beginning of the SNR); distal safe zone (the intercondylar axis and the middle of SNR); lateral safe zone (the lateral epicondyle and the distal end of SNR). In conclusion, it was aimed to correlate the osseus palpable landmarks of humerus with the course of the radial nerve for a safe surgery as the sulcus nervi radialis region is one of the main risky areas for the radial nerve palsies.     

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.