A flow cytometric approach to study intracellular-free Ca2+ in Crassostrea gigas haemocytes.

Bivalve haemocytes are essential in defence mechanisms including phagocytosis. They also produce molecules including hydrolytic enzymes and antimicrobial peptides that contribute to pathogen destruction. Although haemocyte activities have been extensively studied, relatively little is known about the intracellular signalling pathways that are evoked during haemocyte activation and especially the role of calcium. Flow cytometry has been used for the first time to define the effect of cell incubation in haemolymph and artificial sea water (ASW) on Pacific oyster, Crassostrea gigas, haemocytes. Cell viability, enzymatic activities (esterases and aminopeptidases), phagocytosis and granulocyte percentage were analysed. Viability and some activities were different in haemolymph and ASW. Cytoplasmic-free calcium in circulating haemocytes was then investigated by flow cytometry in both media using a calcium probe (Fluo-3/AM). To explore calcium homeostasis, different calcium modulators were tested. The calcium chelator Bapta/AM (10 microM) reduced significantly the percentage of Fluo-3-positive cells in ASW. In addition, ryanodine (5 microM) induced a significant enhancement of the percentage of Fluo-3 positive cells in haemolymph and in ASW. Flow cytometry may be used to study calcium movements in C. gigas haemocytes, but several haemocyte incubation media need to be tested in order to confirm results. The objective of the study should be considered before selecting a particular experimental medium.

Reduction in injury rates in nursing personnel through introduction of mechanical lifts in the workplace.

BACKGROUND: Health care workers incur frequent injuries resulting from patient transfer and handling tasks. Few studies have evaluated the effectiveness of mechanical lifts in preventing injuries and time loss due to these injuries. METHODS: We examined injury and lost workday rates before and after the introduction of mechanical lifts in acute care hospitals and long-term care (LTC) facilities, and surveyed workers regarding lift use. RESULTS: The post-intervention period showed decreased rates of musculoskeletal injuries (RR = 0.82, 95% CI: 0.68-1.00), lost workday injuries (RR = 0.56, 95% CI: 0.41-0.78), and total lost days due to injury (RR = 0.42). Larger reductions were seen in LTC facilities than in hospitals. Self-reported frequency of lift use by registered nurses and by nursing aides were higher in the LTC facilities than in acute care hospitals. Observed reductions in injury and lost day injury rates were greater on nursing units that reported greater use of the lifts. CONCLUSIONS: Implementation of patient lifts can be effective in reducing occupational musculoskeletal injuries to nursing personnel in both LTC and acute care settings. Strategies to facilitate greater use of mechanical lifting devices should be explored, as further reductions in injuries may be possible with increased use.

Randomized prospective study of the impact of three needleless intravenous systems on needlestick injury rates.

OBJECTIVE: To determine the impact of three needleless intravenous systems on needlestick injury rates. DESIGN: Randomized controlled trial. SETTING: 1,000-bed tertiary-care Midwestern hospital. PARTICIPANTS: Nursing personnel from general medical, general surgical, and intensive-care units. INTERVENTIONS: From June 1992 through March 1994, a metal blunt cannula (MBC), two-way valve (2-way), and plastic blunt cannula (PBC) were introduced into three study areas, and needlestick injury rates were compared to three control areas using traditional needled devices. RESULTS: 24 and 29 needlestick injuries were reported in study and control areas. Intravenous-therapy-related injuries comprised 45.8% and 57.1% of injuries in each area. Thirty-seven percent and 20.7% of study and control area needlestick injuries were considered to pose a high risk of bloodborne infection. The 2-way group had similar rates of total and intravenous-related needlestick injuries compared to control groups. The PBC group had lower rates of total and intravenous-related needlestick injuries per 1,000 patient-days (rate ratios [RR], 0.32 and 0.24; 95% confidence intervals [CI95], 0.12-0.81 and 0.09-0.61; P = .02 and P = .003, respectively) and per 1,000 productive hours worked (RR, 0.11 and 0.08; CI95, 0.01-0.92 and 0.01-0.69; P = .03 and P = .005, respectively) compared to controls. CONCLUSIONS: Needlestick injuries continued in study areas despite the introduction of needleless devices, and risks of bloodborne pathogen transmission were similar to control areas. The PBC device group noted lower rates of needlestick injuries compared to controls, but there were problems with product acceptance, correct product use, and continued traditional device use in study areas. Low needlestick injury rates make interpretations difficult. Further studies of safety devices are needed and should attempt greater control of worker behavior to aid interpretation.