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.     

Early experience with laparoscopic herniorrhaphy: results after the first 60 procedures.

The results of the first 60 consecutive laparoscopic hernia repairs performed in Calderdale are presented. These results are encouraging as recovery from surgery is much quicker and allows a shorter hospital stay and a speedier return to work than conventional operations. The laparoscopic procedure takes longer to perform, although this does not seem unacceptable once experience is gained. At present it remains quite expensive and further reductions in hospital stay will need to be achieved to ensure that there is no overall increase in the financial resources required.     

Development of a high performance zinc-62/copper-62 radionuclide generator for positron emission tomography.

Clinical utilisation of positron emission tomography could be enhanced by the availability of short-lived radionuclides derived from generator systems. The zinc-62/copper-62 combination is one such system which could be used as a source for a number of copper-62 radiopharmaceuticals. We have developed and optimised a high activity (5.6 GBq, 150 mCi) zinc-62/copper-62 generator to provide 62Cu in a form that is suitable for direct labelling of pyruvaldehyde-bis-(N4-methylthiosemicarbazone)-copper(II), Cu(PTSM). The distribution coefficients of Zn(II) and Cu(II) between anion-exchange resin and various hydrochloric acid/organic solvent mixtures were measured. Based on these measurements a generator eluent of 0.3 M HCl/40% ethanol provided 62Cu in greater than 90% yield in a 3-ml volume. A very low 62Zn breakthrough of less than 3 x 10(-7)% was achieved. Copper-PTSM was successfully labelled with the no-carrier-added 62Cu eluent directly from the generator with 94% radiochemical yield.     

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.      

Butyrate increases production of human chimeric IgG in CHO-K1 cells whilst maintaining function and glycoform profile

The influence of sodium butyrate on the production and glycosylation of recombinant mouse/human chimeric antibody by transfected CHO-K1 cells was investigated. We selected cells expressing 'wild-type' antibody with a human IgG3 heavy chain and a mutant of this molecule in which Phe 243 is replaced by Ala. These proteins have previously been shown to exhibit very different glycoform profiles with the mutant IgG being comprised of glycoforms having a high galactose and sialic acid content. Cell culture with 0-5 mM butyrate was shown to effect a 2-4-fold increase in antibody production whilst the induction of apoptosis was observed in a dose-dependent manner. The optimal butyrate concentration was observed to be 2 mM. The glycoform profile of each antibody produced in the presence of butyrate was analyzed by HPAEC-PAD and shown to be unchanged, relative to that produced in the absence of butyrate. Biological activity was evaluated by the ability of the antibodies to trigger superoxide generation, through Fc gamma RI, and shown to be independent of production in the presence or absence of butyrate. A similar increase in production was observed for a high antibody-producing cell line when expanded in a hollow fibre bioreactor under low-serum conditions (1%). These results demonstrated that butyrate is of value for increasing the productivity of CHO-K1 for recombinant IgG and does not compromise either glycosylation or biological activity.