Mepilex Border Sacrum and Heel Dressings for the Prevention of Pressure Ulcers: A NICE Medical Technology Guidance.

Mepilex Border Sacrum and Heel dressings are self-adherent, multilayer foam dressings designed for use on the heel and sacrum aiming to prevent pressure ulcers. The dressings are used in addition to standard care protocols for pressure ulcer prevention. The National Institute for Health and Care Excellence (NICE) selected Mepilex Border Sacrum and Heel dressings for evaluation. The External Assessment Centre (EAC) critiqued the company's submission. Thirteen studies (four randomised controlled trials and nine nonrandomised comparative studies) were included. The majority of studies compared Mepilex Border Sacrum dressings (plus standard care) with standard care alone. Comparative evidence for Mepilex Border Heel dressings was limited. A meta-analysis indicated a non-statistically significant difference in favour of Mepilex Border Sacrum dressings for pressure ulcer incidence [RR 0.51 (95% CI 0.22-1.18)]. The company produced a de novo cost model, which was critiqued by the EAC. After the EAC updated input parameters, cost savings of £19 per patient compared with standard care alone for pressure ulcer prevention were estimated with Mepilex Border dressings predicted to be cost saving in 57% of iterations. The Medical Technologies Advisory Committee reviewed the evidence and judged that, although Mepilex Border Heel and Sacrum dressings have potential to prevent pressure ulcers in people who are considered to be at risk in acute care settings, further evidence is required to address uncertainties around the claimed benefits of the dressings and the incidence of pressure ulcers in an NHS acute-care setting. After a public consultation, NICE published this as Medical Technology Guidance 40.

Capillary electrochromatography on silica columns: factors influencing performance.

Much capillary electrochromatography (CEC) work is carried out on bonded silica packings which offer many advantages: the number of such packings which are available; the fact that the chemistry of bonding and the separation process are fairly well understood; and the possibility of the transfer to CEC of existing HPLC methods. Packing methods for the preparation of CEC columns have been investigated. The problems inherent in the use of burned-in frits remains an obstacle, but can be at least partially overcome by minimising the length and by silanisation. The influence of a variety of mobile phase variables on aspects of CEC is in agreement with theory for: ionic strength, organic content (including isoeluotropy), and pH. Temperature can be used as a variable to change column selectivity in CEC. The influence of pH on electroosmotic flow (EOF) by changing the degree of ionisation of residual silanol groups is similar for a wide range of neutral bonded groups, but is much less marked for bonded sulphonic acid groups. The EOF may be reversed for bonded groups containing nitrogen.

Behavior of cation-exchange materials in capillary electrochromatography.

The behavior of a strong, cation-exchange material (propanesulfonic acid, SCX) has been studied in capillary electrophoresis (CE) and capillary electrochromatography (CEC) by the use of coated and packed capillaries. In aqueous electrolytes, the SCX-coated capillary showed a far more consistent electroosmotic flow over the pH range 3.6-10.5, compared to untreated fused silica. However, in similar electrolytes containing 80% (v/v) acetonitrile, both coated and untreated capillaries performed similarly, casting doubts upon the stability of the SCX coating. The effect of voltage and mobile-phase parameters such as pH, ionic strength, and organic content was studied in CEC for both 3-µm SCX and C(18) packing materials, and the results were compared in terms of linear velocities, currents, and conductivities. Only at pH 5 and below was a higher EOF velocity than expected observed for the SCX column. In accordance with theory, the EOF was seen to increase with decreasing ionic strength for the C(18) column. However, for the SCX column, this was not the case: the EOF showed a general reduction as the ionic strength was decreased. The greatest anomaly was observed on changing the acetonitrile composition: the EOF showed a consistent decline with increasing organic, whereas the EOF in both the open capillary and C(18) column decreased and then started to rise with acetonitrile contents above 70% (v/v).

Interaction of chick oviduct progesterone receptor with immobilized aurintricarboxylic acid.

Aurintricarboxylic acid (ATA) was immobilized on Sepharose 4B via a carbodiimide coupling mechanism. A majority of the chick oviduct progesterone receptor was retained on the affinity resin and could be recovered upon washing the column with buffer containing free ligand or 3 M guanidine-HCl. The [3H]progesterone-receptor complex retained its integrity following the chromatography on ATA-Sepharose as judged by sedimentation analysis. The procedure allowed significant purification of progesterone receptor: SDS-polyacrylamide gel electrophoresis of the purified preparation revealed elimination of many peptide bands present in the cytosol prior to ATA-Sepharose chromatography. The technique thus has a clear potential in characterization and purification of progesterone receptor.