Isolation and characterization of transposon-induced mutants of Pseudomonas aeruginosa deficient in production of exoenzyme S.

Exoenzyme S is an extracellular product of Pseudomonas aeruginosa. This enzyme catalyzes the transfer of ADP-ribose from NAD to a number of as yet unidentified eucaryotic proteins, but it is distinct from toxin A. To evaluate the role of exoenzyme S in the pathogenicity of P. aeruginosa, we isolated transposon-induced mutants of strain 388, a clinical isolate that produces exoenzyme S but no toxin A. The transposon Tn1 was introduced by using a temperature-sensitive derivative of plasmid RP1. A Tn1-induced mutant was found which had no detectable exoenzyme S activity or antigen in culture supernatants or in cell lysates. Except for its lack of exoenzyme S and resistance to carbenicillin, this mutant was indistinguishable from the parent strain. When tested in an experimental mouse burn infection model, this Tn1-induced mutant was reduced in virulence by at least 2,000-fold, suggesting a role for exoenzyme S in the virulence of this strain.     

Preferential inhibition of growth and protein synthesis in Rous sarcoma virus transformed cells by diphtheria toxin.

Protein synthesis in Rous sarcoma virus-transformed cultured chick embryo cells is shown to be more sensitive to diphtheria toxin than protein synthesis in normal chick embryo fibroblasts. Similarly, cells from viral-induced sarcomas are more sensitive to diphtheria toxin than cells from normal tissues of the same chicken. Diphtheria toxin inhibits the growth of virus-transformed chick cells in culture at a concentration that has no effect on control cells.     

Patterns of use of group O, Rh-negative red cells in a large metropolitan area and an action plan to control utilization

BACKGROUND: In southeastern Michigan, the group O, Rh-negative (O-) red cell supply was below emergency levels during one-sixth of 1994, despite 43-percent overcollection of O- red cell units relative to the size of the O- patient population. O- red cell units are overutilized because of their universal ABO and Rh compatibility. This study evaluated how hospitals in a large metropolitan area utilized O- red cell units, so that strategies could be devised to reduce O- usage. STUDY DESIGN AND METHODS: Through an O- red cell utilization survey, 56 hospitals were encouraged to collect three months' worth of transfusion data, either prospectively or retrospectively. O- usage was compared to total red cell usage and categorized into transfusions to O- patients, those to non-O- patients, and the number of O- units that outdated. RESULTS: Of 40,616 units transfused in 38 hospitals, 3,535 (8.7%) were O-; 71 percent of the O- units were transfused to O- patients, 28 percent were transfused to non-O- patients, and 1 percent outdated. Hospital transfusions to O- patients appeared to correlate with the racial makeup of the patient population, while hospital transfusions to non-O- patients appeared to correlate with hospital size and the hospital's transfusion practices. CONCLUSION: O- red cell usage in a hospital is dependent on the racial and ethnic mix of the hospital's patient population, the amount of transfusion activity, and the hospital's transfusion practices. An understanding of the dynamics of O- usage allowed the development of strategies to decrease O- utilization.     

Home-based subcutaneous immunoglobulin G replacement therapy under real-life conditions in children and adults with antibody deficiency

Background

Subcutaneous immunoglobulin (SCIG) therapy is an alternative to intravenous immunoglobulin (IVIG) therapy.

Methods

We evaluated the efficacy and safety of the SCIG Vivaglobin^® (formerly known as Beriglobin^® SC) under real-life conditions in a post-marketing observational study in 82 patients with primary or secondary antibody deficiencies. Health-related quality of life (HRQoL) was evaluated in a subset of 30 patients previously treated with IVIG (including 11 children < 14 years) using the Short Form 36 (SF-36) for patients ≥ 14 years of age (adults) and the Child Health Questionnaire - Parental Form 50 (CHQ-PF50) for children < 14 years of age. Treatment preferences were assessed in adults.

Results

The mean serum immunoglobulin G (IgG) trough level during SCIG treatment (7.5 g/L) was higher than during previous IVIG treatment (6.6 g/L; p < 0.01). The investigators assessed the efficacy of SCIG therapy as "excellent" in 89% of patients. No systemic adverse drug reactions were observed. Improvements by ≥ 5 points were observed in 5 of 8 SF36 subscales and in 6 of 12 CHQ-PF50 subscales. Statistically significant improvements (p ≤ 0.05) were observed for the SF-36 subscales of bodily pain, general health perceptions, and vitality (adults), and for the CHQ-PF50 subscales of general health perceptions, parental impact - time, parental impact - emotional, and family activities (children). Patients preferred SCIG over IVIG therapy (92%) and home therapy over therapy at the clinic/physician (83%).

Conclusion

This study confirms that therapy with Vivaglobin^® at home is effective, safe, well tolerated, and improves quality of life in patients with antibody deficiency.     

Differential effects of impaired mitochondrial energy production on the function of mu and delta opioid receptors in neuronal SK-N-SH cells

Oxidative stress contributes to changes in neurosensory processing, including pain, that occur during aging and neurodegeneration. The effects of neuronal oxidation on the opioid system are poorly understood. In this in vitro study, oxidative stress was induced by 3-nitroproprionic acid (3-NPA) in opioid-responsive differentiated SK-N-SH cells. Changes in the inhibitory effects of opioid receptor agonists on intracellular cAMP were used as a marker of the function of mu and delta opioid receptors (MOR and DOR, respectively). Cells were treated with morphine and selective MOR and DOR agonists and antagonists to characterize the function of each receptor subtype. Cyclic AMP (cAMP) was measured by enzyme immunoassay. Levels of reactive oxygen species (ROS) were assessed using the 2',7'-dichlorofluorescin diacetate assay. Exposure of cells to 3-NPA resulted in an increase in ROS. After 3-NPA exposure, there was a significant attenuation of the inhibitory effect of morphine and DAMGO but not of DPDPE on cAMP. In cells pretreated with CTOP, 3-NPA did not change the inhibitory effect on cAMP. These findings demonstrate for the first time that under conditions of mitochondrial damage, the function of MOR is significantly decreased, while the function of DOR does not change, suggesting that the effect of 3-NPA on opioid receptors is subtype-specific.