A meta-analysis on dose-response relationship between night shift work and the risk of breast cancer.

This study aimed to conduct a systematic review to sum up evidence of the associations between different aspects of night shift work and female breast cancer using a dose-response meta-analysis approach. We systematicly searched all cohort and case-control studies published in English on MEDLINE, Embase, PSYCInfo, APC Journal Club and Global Health, from January 1971 to May 2013. We extracted effect measures (relative risk, RR; odd ratio, OR; or hazard ratio, HR) from individual studies to generate pooled results using meta-analysis approaches. A log-linear dose-response regression model was used to evaluate the relationship between various indicators of exposure to night shift work and breast cancer risk. Downs and Black scale was applied to assess the methodological quality of included studies. Ten studies were included in the meta-analysis. A pooled adjusted relative risk for the association between 'ever exposed to night shift work' and breast cancer was 1.19 [95% confidence interval (CI) 1.05-1.35]. Further meta-analyses on dose-response relationship showed that every 5-year increase of exposure to night shift work would correspondingly enhance the risk of breast cancer of the female by 3% (pooled RR = 1.03, 95% CI 1.01-1.05; Pheterogeneity < 0.001). Our meta-analysis also suggested that an increase in 500-night shifts would result in a 13% (RR = 1.13, 95% CI 1.07-1.21; Pheterogeneity = 0.06) increase in breast cancer risk. This systematic review updated the evidence that a positive dose-response relationship is likely to present for breast cancer with increasing years of employment and cumulative shifts involved in the work.

Bactericidal and sporicidal performance of a polymer-encapsulated chlorine dioxide-coated surface.

AIMS: To investigate the physical characteristics and the bactericidal and sporicidal potential of a polymer-encapsulated ClO(2) coating. METHODS AND RESULTS: An antimicrobial coating based on polymer-encapsulated ClO(2) was developed. A low viscosity, water/oil/water double emulsion coating was formulated for easy on-site application. Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis and Staphylococcus aureus were applied onto the coating to study the bactericidal capabilities of the coating. The bactericidal performance of the coating increased when the contact time with the tested bacteria increased. Over 99% of the E. coli, Ps. aeruginosa, B. subtilis were killed with a contact time of 30 min. Although endospores of B. subtilis are more resistant, about 75% of the spores were killed after 72 h on the coating. Moreover, a sustained release of gaseous ClO(2) was achieved to maintain about 90% removal of B. subtilis with a 10-min contact time during a 28-day study period. The coating also exhibits antiadhesive properties against bacteria. CONCLUSIONS: A polymer-encapsulated ClO(2) coating with sustained release of ClO(2) and promising bactericidal and sporicidal features was tested for 28 days. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides a new direction for developing polymer-encapsulated ClO(2) coatings that possess persistent bactericidal and sporicidal properties.

Evaluation of a simplified therapeutic intervention scoring system (TISS-28) and the modified early warning score (MEWS) in predicting physiological deterioration during inter-facility transport.

INTRODUCTION: There is an emerging demand for inter-facility transport (IFT) of patients in recent years following changes in the healthcare framework in Hong Kong but this carries certain risks. Anticipation of possible deterioration of patients is important for patient safety and therefore risk stratification of patients before transport is important. OBJECTIVE: This study evaluated the simplified therapeutic intervention scoring system (TISS-28) and modified early warning score (MEWS) in predicting physiological deterioration en route. METHODS: This is a prospective single centre study of all emergency IFT for adult patients, excluding patients with obstetric conditions, occurring between 1 January 2005 and 30 June 2006. The severity of illness was quantified in terms of TISS-28 and MEWS. Mann-Whitney test and receiver operator characteristic (ROC) curves were used to illustrate and compare their performance. RESULTS: Among 102 patients requiring IFT, 28 had physiological deterioration en route (27%). The TISS-28 scores upon dispatch ranged from 5 to 34 with a mean of 16.5+/-5.71 whereas MEWS ranged from 0 to 11 with a mean of 2.82+/-2.01. The incidence of physiological deterioration en route was significantly greater with a higher MEWS score (P=0.001) but this was not seen with the TISS-28 score. The area under the ROC curve for the predictive value of MEWS was 0.71 which performed better than TISS-28 (area under the curve=0.53). CONCLUSION: IFT represents a group of patients with vast heterogeneity. TISS-28 is not a useful tool for risk stratification prior to transport. MEWS was able to identify patients at risk but was not ideal.

A microplate compression method for elastic modulus measurement of soft and viscoelastic collagen microspheres.

Hydrogel-based microspheres are commonly used for drug and cell delivery in regenerative medicine. Characterization of their physical and mechanical properties is important in monitoring their quality during fabrication and in predicting their performance upon injection. However, existing methods have limitations in measuring these micron-sized, soft and viscoelastic spherical structures. In this study, a protocol is developed to measure the elastic modulus of non-linear viscoelastic spheres by microplate compression, and is applied to collagen microspheres fabricated with or without cells. During the measurement, a microsphere is placed on a rigid surface and is compressed by a calibrated flexible microplate gripped to a rigid end. A step increase in the displacement rate of the rigid end of the flexible microplate is introduced and the reduced elastic modulus of the microsphere is calculated from the deformation response of the microsphere, using an equation derived in this study. The reduced elastic modulus of collagen microspheres with and without mesenchymal stem cells measured by this method was 9.1 kPa and 132 Pa, respectively.

Knowledge of inter-facility transport among emergency nurses in Hong Kong: a questionnaire survey.

INTRODUCTION: Inter-facility transport (IFT) is a dynamic process and its quality largely depends on pre-transport preparation, emergency equipment support and recognition of possible en route adverse events. This study aims to evaluate knowledge of IFT among emergency nurses of three Accident and Emergency Departments in Hong Kong. METHODS: Questionnaires were distributed to registered nurses of the three departments. Data was sought on participants' characteristics, knowledge on equipment preparation and management of en route adverse events. Four clinical IFT scenarios were set for participants and answers were scored. Measured outcomes were defined as (1) relationships between clinical experience and relevant training in IFT with questionnaire results, (2) staff knowledge of the equipment carried routinely in ambulances and (3) the en route adverse events encountered according to the participants' past experience. RESULTS: Participants' test scores ranged from 24 to 37 (out of 40) with a mean of 30.6 (95% confidence interval 29.7-31.5). Participants with more clinical experience demonstrated significantly better test scores (p<0.05). Most participants were familiar with the monitoring devices carried in ambulances but were less familiar with the pharmacologic agents and airway devices available routinely in Hong Kong ambulances. Thirty participants (59%) had encountered en route adverse events in the past. CONCLUSION: Nurses in emergency departments in Hong Kong have good knowledge of IFT. Extensive clinical experience is related to better IFT knowledge. IFT training for nurses should emphasize available ambulance service resources and capabilities.

Effects of additives on heat denaturation of rhDNase in solutions.

PURPOSE: To study the thermal stability of recombinant human deoxyribonuclease I (rhDNase) in aqueous solutions. METHODS: Differential scanning calorimetry (DSC) was used to measure the denaturation or melting temperature (T(m)) and enthalpy (H(m)) of rhDNase. The effects of denaturants (guanidine HCl and urea) and additives (mainly divalent cations and disaccharides) were investigated at pH 6-7. RESULTS: The T(m) and H(m) of rhDNase in pure water were measured as 67.4 degrees C and 18.0 J/g respectively, values typical of globular proteins. The melting peak disappeared on re-running the sample after cooling to room temperature, indicating that the thermal denaturation was irreversible. The latter was due to the occurrence of aggregation accompanying the unfolding process of rhDNase. Size exclusion chromatography indicated that during heat denaturation, rhDNase formed soluble high molecular weight aggregates with a molecular size >300kD estimated by the void volume. Of particular interest are the divalent cations: Ca(2+) stabilizes rhDNase against thermal denaturation and elevates T(m) and H(m) while Mg(2+), Mn(2+) and Zn(2+) destabilize it. Sugars also stabilize rhDNase. As expected, denaturants destabilize the protein and lower the T(m) and H(m). All destabilization of rhDNase can be prevented by adding Ca(2+) to the solutions. CONCLUSIONS: CaCl(2) and sugars were found to stabilize rhDNase against thermal denaturation while divalent cations, urea and guanidine HCl destabilize the protein. The effects could be explained by a mixture of mechanisms. For Ca(2+) the protective effect is believed to be due to an ordering of the rhDNase structure in its native state, and by prevention of breaking of a disulfide bridge, thus making it less susceptible to unfold under thermal stress.

Development of a mathematical model for the water distribution in freeze-dried solids.

PURPOSE: Development of a mathematical model to provide information about the amount of water associated with a protein and an excipient in a lyophilized product. METHODS: The moisture content of the product and the mass fraction of each component were used to derive a model for the calculation of the mass of water associating with each component. The model was applied to lyophilized formulations of rhDNase containing various amounts of mannitol or lactose. The total water content was investigated by thermogravimetry, crystalline properties by X-ray powder diffraction and water uptake behaviour using a moisture microbalance system. RESULTS: Calculations based on the model suggest that in a lyophilized rhDNase-mannitol formulation where the sugar is crystalline, most of the water is taken up by the protein. However, in the lyophilized rhDNase-lactose formulation where the sugar is amorphous, water is taken up by both the sugar and protein to a comparative extent. At high relative humidities when the amorphous sugar undergoes crystallization, the model can accommodate such a change by allowing for the formation of an additional crystalline phase. CONCLUSIONS: The rhDNase-sugar formulations show excellent conformity to the model which provides quantitative information about the distribution of water in the lyophilized binary protein-excipient products.

Provision of an out-of-hours blood banking service at a satellite hospital without blood bank staff.

With limited health care resources and financial constraints, many hospitals have to reduce their service. Computer crossmatching has been accepted as a safe crossmatching procedure for patients without clinically significant alloantibodies. We report here a novel way of providing an out-of-hours blood banking service at a satellite hospital. The system is easy to introduce and can provide a safe transfusion service to small hospitals without stationing blood banking staff at these hospitals after regular working hours.