T cell subsets in human colostrum

Lymphocytes from 10 paired colostrum and peripheral blood specimens were examined to determine if the colostral T cell population differs from the peripheral blood T cell population in subset distribution. The percentages of lymphocytes staining with OKT3, OKT4, and OKT8 murine monoclonal antibody were determined. Lymphocytes from colostrum were 74.7 +/- 2.5% OKT3+, 50.6 +/- 2.3% OKT4+, 24.0 +/- 1.7% OKT8+, whereas peripheral blood lymphocytes were 78.7 +/- 1.9% OKT3+, 48.4 +/- 1.4% OKT4+, and 29.8 +/- 1.6% OKT8+. The percentage of colostrum lymphocytes positive for OKT3 was significantly although not strikingly lower than the OKT3 percentage for blood lymphocytes (p less than 0.05). This difference was due to the lower percentage of OKT8 positive lymphocytes in colostrum compared with blood (p less than 0.01). Although the T cell subset distribution of colostrum generally appears to be similar to that in the peripheral blood, there were small differences in OKT3 and OKT8 percentages that were statistically significant suggesting the possibility of some selectivity of the colostral T cell population.     

The effects of severe visual challenges on steering performance in visually healthy young drivers.

PURPOSE: Two experiments explored the extent to which induced blur, reduced luminance, and reduced visual fields affect drivers' steering performance in a driving simulator. METHODS: In experiment 1, ten young participants (M = 21.2 years) drove at approximately 89 km/h (55 mph) along a curvy roadway while being exposed to blur (0 to + 10 D), luminance (0.003 to 16.7 cd/m), and visual field (1.7 and 150 degrees) manipulations. In experiment 2, a new group of ten young participants (M = 18.5 years) drove while exposed to seven visual field sizes (1.7 to 150 degrees). RESULTS: Steering was sensitive to a reduced field size but not to the blur and luminance challenges. Acuity, on the other hand, was sensitive to the blur and luminance challenges but not to reduced field size. DISCUSSION: In healthy young drivers, steering performance is remarkably robust to severe blur and to extremely low luminances. These results support a key element of the selective degradation hypothesis advanced by Leibowitz and colleagues--that steering abilities are preserved at night even when the ability to recognize objects and hazards is not. Additional research should address the other element of this hypothesis--that drivers fail to appreciate the extent to which their visual abilities are degraded at night.     

Phenotypic and genotypic characterization of prolyliminopeptidase-negative Neisseria gonorrhoeae isolates in Denmark

In the study presented here 26 recent Danish clinical isolates of prolyliminopeptidase (PIP)-negative Neisseria gonorrhoeae were phenotypically and genotypically characterized to investigate whether one or more PIP-negative strains are circulating in the Danish community. The profiles of these isolates were compared with those of three isolates from a recent outbreak of PIP-negative N. gonorrhoeae infection in the UK. Twenty-five of the Danish isolates and all three UK isolates had similar antibiograms and were designated serovar IB-4. Genotypic characterization by pulsed-field gel electrophoresis, porB1b gene sequencing, and opa-typing revealed that these isolates were indistinguishable or closely related. The results indicate that at least one PIP-negative N. gonorrhoeae strain is currently circulating in the Danish community, and this strain is indistinguishable from the one that caused an outbreak in the UK.An erratum to this article can be found at     

Activity measurements of the high-energy pure beta-emitters 89Sr and 90Y by the TDCR efficiency calculation technique.

The absolute activities of the pure beta-emitters 89Sr and 90Y have been determined by a direct method, namely the triple-to-double coincidence ratio (TDCR) efficiency calculation technique. This undertaking has extended further the number of radionuclides that have been standardized by this non-extrapolation liquid scintillation (LS) method. Both measurements were carried out within the framework of international key comparisons under the auspices of the International Bureau of Weights and Measures (BIPM). The TDCR results agreed well with those of other participating national laboratories, most using alternative (tracer) methods.