Surface markers of human eosinophils

Peripheral blood eosinophils from patients with eosinophilia and from healthy subjects were studied for surface immunoglobulins, receptors for the Fc region of IgG, complement receptors, and spontaneous rosette formation with sheep and mouse erythrocytes. Eosinophils were found to have receptors for complement and for aggregated IgG, and to have the same two types of complement receptors as do lymphocytes and monocytes. Immune adherence type receptors were specific for C4 or C3b, while C3d receptors were specific for C3d but unreactive with C4. Eosinophils differed from fully mature neutrophils in that the former had C3d receptors and relatively weak immune adherence (C4 or C3b) receptors, while the later did not have the C3d receptors and had strong immune adherence receptors. Eosinophil phagocytosis of complement-receptor bound erythrocytes was dependent on the presence of IgG in the antibody coating the red blood cells; this requirement for IgG resembled that found in neutrophil phagocytosis. No surface Ig or spontaneous erythrocyte rosette formation was observed with eosinophils.     

Indications for conjunctival transplantation

Long-term follow-up (two to five years) of 12 unilateral chemical burn patients treated by conjunctival transplantation shows permanent stabilization of the ocular surface. The procedure was used in another group of five patients with unilateral recalcitrant epithelial defects. Regardless of the etiology of the epithelial defect, prompt healing of the surface occurs after conjunctival transplantation with no further stromal loss and long-term stabilization of the surface. Such results suggest that epithelial replacement may be a valuable therapeutic approach to a variety of ocular surface disorders.     

Comparing traditional and Rasch analyses of the Mississippi PTSD Scale: revealing limitations of reverse-scored items

This study examined whether Rasch analysis could provide more information than true score theory (TST) in determining the usefulness of reverse-scored items in the Mississippi Scale for Posttraumatic Stress Disorder (M-PTSD). Subjects were 803 individuals in inpatient PTSD units at 10 VA sites. TST indicated that the M-PTSD performed well and could be improved slightly by deleting one item. Factor analysis using raw scores indicated that the reverse-scored items formed the second factor and had poor relationships with normally scored items. However, since item-total correlations supported their usefulness, they were kept. The subsequent Rasch analysis indicated that five of the seven worst fitting items were reverse-scored items. We concluded that using reversed items with disturbed patients can cause confusion that reduces reliability. Deleting them improved validity without loss of reliability. The study supports the use of Rasch analysis over TST in health research since it indicated ways to reduce respondent burden while maintaining reliability and improving validity.     

Preservation of algal and higher plant ribosomal RNA integrity during extraction and electrophoretic quantitation

Isolation of high molecular weight ribosomal RNA from the wall-less alga Olisthodiscus luteus and the angiospermous plant Sauromatum guttatum is described. It has been found that a buffer which contains magnesium must be used to successfully isolate Olisthodiscus rRNA whereas the isolation of intact Sauromatum rRNA requires a buffer system containing a high amount of the chelator EDTA. Sauromatum but not Olisthodiscus extracts were contaminated with ribonuclease unless the inhibitor diethylpyrocarbonate was used during the ribonucleic acid extraction procedure. Nuclease levels were monitored by coincubating [3H]-labeled Escherichia coli ribosomal RNA with the experimental RNA samples. The effects of detergents on the isolation and quantitation of RNA are presented, and methods to avoid loss of highly thermolabile plant ribosomal RNA species are discussed.     

The CTFA Evaluation of Alternatives Program: an evaluation of in vitro alternatives to the Draize primary eye irritation test. (Phase III) surfactant-based formulations

The CTFA Evaluation of Alternatives Program is an evaluation of the relationship between data from the Draize primary eye irritation test and comparable data from a selection of promising in vitro eye irritation tests. In Phase III, data from the Draize test and 41 in vitro endpoints on 25 representative surfactant-based personal care formulations were compared. As in Phase I and Phase II, regression modelling of the relationship between maximum average Draize score (MAS) and in vitro endpoint was the primary approach adopted for evaluating in vitro assay performance. The degree of confidence in prediction of MAS for a given in vitro endpoint is quantified in terms of the relative widths of prediction intervals constructed about the fitted regression curve. Prediction intervals reflect not only the error attributed to the model but also the material-specific components of variation in both the Draize and the in vitro assays. Among the in vitro assays selected for regression modeling in Phase III, the relationship between MAS and in vitro score was relatively well defined. The prediction bounds on MAS were most narrow for materials at the lower or upper end of the effective irritation range (MAS = 0-45), where variability in MAS was smallest. This, the confidence with which the MAS of surfactant-based formulations is predicted is greatest when MAS approaches zero or when MAS approaches 45 (no comment is made on prediction of MAS > 45 since extrapolation beyond the range of observed data is not possible). No single in vitro endpoint was found to exhibit relative superiority with regard to prediction of MAS. Variability associated with Draize test outcome (e.g. in MAS values) must be considered in any future comparisons of in vivo and in vitro test results if the purpose is to predict in vivo response using in vitro data.