Evaluation of the acceptability of a needleless vascular-access system by nurses

BACKGROUND: Needleless intravenous-access devices have been introduced in an effort to reduce needlestick injuries and possible transmission of blood-borne pathogens to health care workers. However, there are no data on the acceptance of these devices by nursing personnel. METHODS: A survey of nursing personnel was taken at Indiana University Medical Center after introduction of a needleless intravenous device to determine their opinion after use of the needleless device. RESULTS: The majority of the nurses (72 of 94, 70%) had a favorable overall opinion of the device. Among those with a favorable opinion, 76% (55/72) responded that reduced risk of needlestick injury was the most important reason. Among those who had a negative opinion about the needleless-device system, 32% (7/22) reported that contamination risk was their major concern. Those who were trained before device use were more likely to properly use and maintain the needleless intravenous-access system. Of 89 respondents, 75.3% (67/89) believed that the initial training was adequate; however, 43% (29/67) thought that additional training after using the device for some time would have been beneficial. CONCLUSIONS: Comprehensive education programs that include training before and after device use are necessary if new needleless intravenous-access systems are to be successfully introduced and accepted by nursing personnel.     

Amino acid residues that influence Fc epsilon RI-mediated effector functions of human immunoglobulin E

Immunoglobulin E (IgE) mediates its effector functions via the Fc region of the molecule. IgE binding to and subsequent aggregation of the high-affinity receptor (Fc epsilon RI) by allergen plays a pivotal role in type I hypersensitivity responses. Earlier studies implicated the C epsilon 2 and 3 interface and the A-B loop in C epsilon 3 in the IgE-Fc epsilon RI interaction. These regions and glycosylation sites in C epsilon 3 were now targeted by site-specific mutagenesis. IgE binding to Fc epsilon RI was compared with surface plasmon resonance (SPR) measurements, which assessed the binding of the soluble extracellular domain of Fc epsilon RI to IgE. Kinetic analysis based on a pseudo-first-order model agrees with previous determinations. A more refined SPR-based kinetic analysis suggests a biphasic interaction. A model-free empirical analysis, comparing the binding strength and kinetics of native and mutant forms of IgE, identified changes in the kinetics of IgE-Fc epsilon RI interaction. Conservative substitutions introduced into the A-B loop have a small effect on binding, suggesting that the overall conformation of the loop is important for the complementary interaction, but multiple sites across the C epsilon 3 domain may influence IgE-Fc epsilon RI interactions. Asn394 is essential for the generation of a functional IgE molecule in mammalian cells. A role of Pro333 in the maintenance of a constrained conformation at the interface between C epsilon 2-3 emerged by studying the functional consequences of replacing this residue by Ala and Gly. These substitutions cause a dramatic decrease in the ability of the ligand to mediate stimulus secretion coupling, although only small changes in the association and dissociation rates are observed. Understanding the molecular basis of this phenomenon may provide important information for the design of inhibitors of mast cell degranulation.     

Characterization of T-cell subsets infiltrating post-burn hypertrophic scar tissues

In this study, skin-infiltrating cells were characterized in both the active and remission phases of post-burn hypertrophic scar biopsies. Immunohistochemistry examination of active phase samples showed an abundant presence of Langerhans cells, T cells, macrophages, a low presence of natural killer cells and the lack of B lymphocytes. In active hypertrophic scars T lymphocytes infiltrate deep into the superficial dermis and are also observed in the epidermis: CD3+ cells were present at about 222 +/- 107 per 0.25 mm2. In particular the analysis of lymphocyte subpopulations showed that CD4+ T cells predominate in the dermis as well as in the epidermis of active hypertrophic scars whereas CD8+ cells were less well represented (CD4/CD8 ratio is 2.06). This distribution was also shown in remission phase samples and in normotrophic scar specimens, although the lymphocyte number was significantly lower. Approximately 70 per cent of T lymphocytes present in the tissue involved in active phase hypertrophic scar samples were activated (positive with anti-HLA-DR and IL-2 receptor antibodies) which is significantly higher than remission phase hypertrophic and normotrophic scars, in which positivity was 40 and 38 per cent, respectively. Upon activation, the lesional lymphocytes release several cytokines, locally and transiently, that interact with specific receptors in response to different stimulation. Central to the immune hypothesis of hypertrophic scars is that some of the T-cell lymphokines act on keratinocytes, fibroblasts and other cell types to induce changes characteristic of these scars. The presence and close proximity of activated T lymphocytes and antigen-presenting cells of various phenotypes in both the epidermis and dermis of hypertrophic tissues provides strong circumstantial evidence of a local immune response. However, the manner in which T cells achieve and maintain their activated state in hypertrophic tissues is not yet known, and both antigen-dependent and independent mechanisms may contribute.     

Demographic predictors of asthma treatment site: outpatient, inpatient, or emergency department

We evaluated physical activity changes resulting from a six-month public health model intervention that encouraged seniors (N = 89) 62-91 years of age (mean = 76) living in two low-income congregate housing facilities to increase their physical activity by participating in existing community-based physical activity classes and programs of their choice. The program was offered to everyone regardless of their health problems. Enrollees were encouraged to adopt activities tailored to their preferences, physical abilities, health status, income, and transportation resources. Using a comparison-group design, the intervention group was more active for all comparison months of the intervention period (p values < .05). The intervention also was associated with improvements in self-esteem (p < .05), though not with an array of other measures of health-related quality-of-life. Those who adopted and maintained a new physical activity over the six-month intervention period experienced improvements in anxiety, depression, and overall psychological well-being relative to those who did not. The intervention was subsequently replicated through a senior center (N = 22). A much larger proportion of the senior center sample adopted and maintained a new activity for six months (68%) compared to the congregate facilities sample (35%), which may have been due to differences in recruitment methods and sample characteristics in the two settings. An intervention promoting increased physical activity through the use of existing community resources may help increase physical activity in older adults.     

Insulin has a limited effect on the cell cycle progression in 3T3 L1 fibroblasts

Insulin has pleiotropic effects on the regulation of cellular growth, differentiation, and metabolism. The biochemical events ultimately leading to cell proliferation after insulin treatment have been demonstrated in detail by numerous research groups. However, depending on cell types, it has been shown that insulin has various effects on cell proliferation. Therefore, we attempted to more critically evaluate the effect of insulin on cell proliferation in 3T3 L1 fibroblasts. In this study, we investigated insulin's effect on cell proliferation by using [3H]thymidine incorporation, flow cytometry, and cell counting. In 3T3 L1 fibroblasts studied in 0.5% serum, insulin induced a two-fold increase in [3H]thymidine incorporation over at 48 h, and the maximal rate of DNA synthesis was observed during 8-12 h incubation. The flow cytometric analysis also showed that insulin increased the cell population in the S phase. After insulin treatment for 48 h, cell numbers increased approximately 45% in comparison with 0.5% serum control. Cell division was found to occur only once in 60 h after staining 3T3 L1 fibroblasts with carboxyfluorescein diacetate succinimidyl ester (CFSE). Taken together, this data indicates that insulin stimulated the transit from the G0/G1 to S phase, progressed the cell cycle through the G2/M phase, and increased the cell number. However, under our experimental conditions, cells divided only once in 60 h in the presence of insulin.     

Deconvolution of the fluorescence emission spectrum of human antithrombin and identification of the tryptophan residues that are responsive to heparin binding

Heparin causes an allosterically transmitted conformational change in the reactive center loop of antithrombin and a 40% enhancement of tryptophan fluorescence. We have expressed four human antithrombins containing single Trp --> Phe mutations and determined that the fluorescence of antithrombin is a linear combination of the four tryptophans. The contributions to the spectrum of native antithrombin at 340 nm were 8% for Trp-49, 10% for Trp-189, 19% for Trp-225, and 63% for Trp-307. Trp-225 and Trp-307 accounted for the majority of the heparin-induced fluorescence enhancement, contributing 37 and 36%, respectively. Trp-49 and Trp-225 underwent spectral shifts of 15 nm to blue and 5 nm to red, respectively, in the antithrombin-heparin complex. The blue shift for Trp-49 is consistent with partial burial by contact with heparin, whereas the red shift for Trp-225 and large enhancement probably result from increased solvent access upon heparin-induced displacement of the contact residue Ser-380. The enhancement for Trp-307 may result from the heparin-induced movement of helix H seen in the crystal structure. The time-resolved fluorescence properties of individual tryptophans of wild-type antithrombin were also determined using the four variants and showed that Trp-225 and Trp-307 experienced the largest change in lifetime upon heparin binding, providing support for the steady-state fluorescence deconvolution.     

Transient gene expression from yeast artificial chromosome DNA in mammalian cells is enhanced by adenovirus

The introduction of high molecular weight DNA into mammalian cells is useful for gene expression studies. However, current transfection strategies are inefficient, necessitating propagation of stable DNA transformants prior to analysis of gene expression. Here we demonstrate that transient lipid-mediated DNA transfection can be used to assess gene expression from yeast artificial chromosomes (YACs) containing the 230 kb cystic fibrosis transmembrane conductance regulator gene ( CFTR ) and Escherichia coli lacZ . We also show that psoralen-UV inactivated adenovirus significantly enhances transfection efficiency. The ability to deliver high molecular weight DNA using lipid-mediated transfection should expedite the analysis of large human genes contained within artificial chromosome vectors.     

Solitary pancreas allografts. The role of percutaneous biopsy and standardized histologic grading of rejection

Murine models such as NZB/W F1, NZB.H-2bm12 and MRL.lpr/lpr mice have provided greater insight into the pathogenic mechanisms of lupus. To understand further the roles of T cells and cytokines in the pathogenesis of murine lupus, 11 cloned anti-DNA antibodies augmenting autoreactive T cell lines were derived from NZB/W F1 mice. All these autoreactive cells responded to syngeneic splenic cells and helped syngeneic B cells to produce anti-DNA antibodies, especially the IgG antibody. Ten out of 11 autoreactive T cell lines expressed neither CD4 nor CD8 cell surface markers on their surface. In addition, the cytokine production pattern of these autoreactive T cell lines was predominantly of type 0 (Th0) or type 2 T helper cells (Th2). To further investigate the role of accessory molecules in the activation of these autoreactive T cell lines, expression of IL-2R and heat-stable antigen (HSA) on these autoreactive T cells was analysed. Results suggest that the HSA played a critical role in the activation and function of these double-negative cloned autoreactive T cells.