Rapid linear scale-up of a protein separation by centrifugal partition chromatography.

The scaling up of the separation of two proteins with an aqueous two-phase system (ATPS) from 176 mg with a 500 ml laboratory scale centrifugal partition chromatography (CPC) column to 2.2g with a 6.25 litre pilot-scale column is presented. A model sample system of a mixture of lysozyme and myoglobin was chosen for this study using an ATPS system comprising 12.5% (w/w) PEG-1000:12.5% (w/w) K2HPO4. It was found that the maximum sample concentration possible without precipitation was 2.2mg/ml for each constituent. The optimisation of rotor speed, mobile phase flow rate and sample loading was performed on a laboratory-scale device. It was found that a centrifuge speed of 2000 rpm (224 'g'), 10 ml/min mobile phase flow rate with a 43 ml (10% of active column volume) sample volume gave optimum operating conditions. This was linearly scaled up to pilot scale by increasing mobile phase flow rate, fraction size and sample loading in the ratio of the system capacities (i.e. 12.5:1). Flow rate was therefore increased from 10 ml/min to 125 ml/min, fraction size from 10 ml to 125 ml and sample loading from 43 ml to 500 ml. Rotor speed however was reduced from 2000 rpm on the laboratory device to 1293 rpm on the pilot-scale device to maintain the same 224 'g' field in each chamber, as the pilot-scale CPC unit has a larger rotor radius than the laboratory one. Resolution increased from Rs=1.28 on the 500 ml rotor to Rs=1.88 on the 6.25 litre rotor, giving potential throughputs in batch mode of over 40 g/day.

[Impact of hospital infection on medical expenditures in a continuing care and rehabilitation service at a geriatric hospital]. / Impact de l'infection nosocomiale sur les consommations médicales en service de soins de suite et réadaptation dans un hôpital gériatrique.

The costs of medical expenditures such as drugs, medical devices (MD), biological assays and nurses workload, were measured, before and after the onset of nosocomial infection (NI), in rehabilitation care departments of a 1000-beds geriatric teaching hospital. Data were collected retrospectively in medical records and nursing records. Nurse's workload was measured by the French indicator "Soins Infirmiers Personnalisé à la Personne Soignée" (SIIPS). A week before and a week after the diagnosis of hospital-acquired infection, medical consumptions were compared. During the study 38 of the 206 patients admitted in rehabilitation care wards presented hospital-acquired infection. Data were collected for 31 of these 38 patients. Nosocomial infections are associated with an increased pharmaceutical dispensing: medication (mainly antibiotics) and medical device's cost; and an increased nurse's workload. This study suggests that infection surveillance may be helpful to a better understanding of pharmaceutical dispensing variation in geriatric rehabilitation care departments.