A novel plasma etching and emission monitoring system (PEEMS) to assess protein and lipid spoilation for hydrogel contact lenses

The work presents a new method that combines plasma etching with extrinsic techniques to simultaneously measure matrix and surface protein and lipid deposits. The acronym for this technique is PEEMS - Plasma Etching and Emission Monitoring System. Previous work has identified the presence of proteinaceous and lipoidal deposition on the surface of contact lenses and highlighted the probability that penetration of these spoilants will occur. This technique developed here allows unambiguous identification of the depth of penetration of spoilants to be made for various material types. It is for this reason that the technique has been employed in this thesis. The technique is applied as a 'molecular' scalpel, removing known amounts of material from the target. In this case from both the anterior .and posterior surfaces of a 'soft' contact lens. The residual material is then characterised by other analytical techniques such as UV/visible .and fluorescence spectroscopy. Several studies have be.en carried out for both in vivo and in vitro spoilt materials. The analysis and identification of absorbed protein and lipid of the substrate revealed the importance of many factors in the absorption and adsorption process. The effect of the material structure, protein nature (in terms of size, shape and charge) and environment conditions were examined in order to determine the relative uptake of tear proteins. The studies were extended to real cases in order to study the. patient dependent factors and lipoidal penetration.

Sensor and software use for the glycaemic management of insulin-treated type 1 and type 2 diabetes patients

Lowering glucose levels, while avoiding hypoglycaemia, can be challenging in insulin-treated patients with diabetes. We evaluated the role of ambulatory glucose profile in optimising glycaemic control in this population. Insulin-treated patients with type 1 and type 2 diabetes were recruited into a prospective, multicentre, 100-day study and randomised to control (n = 28) or intervention (n = 59) groups. The intervention group used ambulatory glucose profile, generated by continuous glucose monitoring, to assess daily glucose levels, whereas the controls relied on capillary glucose testing. Patients were reviewed at days 30 and 45 by the health care professional to adjust insulin therapy. Comparing first and last 2 weeks of the study, ambulatory glucose profile-monitored type 2 diabetes patients (n = 28) showed increased time in euglycaemia (mean ± standard deviation) by 1.4 ± 3.5 h/day (p = 0.0427) associated with reduction in HbA1c from 77 ± 15 to 67 ± 13 mmol/mol (p = 0.0002) without increased hypoglycaemia. Type 1 diabetes patients (n = 25) showed reduction in hypoglycaemia from 1.4 ± 1.7 to 0.8 ± 0.8 h/day (p = 0.0472) associated with a marginal HbA1c decrease from 75 ± 10 to 72 ± 8 mmol/mol (p = 0.0508). Largely similar findings were observed comparing intervention and control groups at end of study. In conclusion, ambulatory glucose profile helps glycaemic management in insulin-treated diabetes patients by increasing time spent in euglycaemia and decreasing HbA1c in type 2 diabetes patients, while reducing hypoglycaemia in type 1 diabetes patients.