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D M Briggs

Publications and source records attributed to D M Briggs.

9 recordsLinked to original sources
PubMed2000

Presentation of IFN-gamma to nitric oxide-producing cells: a novel function for mast cells.

We report that mast cells can bind and present IFN-gamma in a functionally active form to macrophages. Flow-cytometric analysis revealed that biotinylated IFN-gamma bound equally well to purified peritoneal mast cells from both IFN-gammaR knockout and wild-type mice, indicating a non-IFN-gammaR binding site. Purified peritoneal mast cells, loaded with IFN-gamma for 30 min and washed, were able to induce NO synthesis by peritoneal macrophages. This response required cell contact and expression of IFN-gammaR on the responding macrophages, but not the mast cells. Human HMC-1 mast cells were also able to present IFN-gamma to mouse macrophages. Enzyme treatment of mouse mast cells revealed that binding of IFN-gamma was predominantly to chondroitin sulfate B (dermatan sulfate). Binding of IFN-gamma to dermatan sulfate was confirmed by inhibition ELISA. This study demonstrates for the first time that mast cells can present IFN-gamma to other cells via glycosaminoglycans. Mast cells may act as a reservoir of surface-stored functionally active cytokines.

Animals↗
PubMed1999

A neurophysiological method of rapid detection and analysis of marine algal toxins.

We have examined the effectiveness of the in vitro rat hippocampal slice preparation as a means of rapidly and specifically detecting the marine algal toxins saxitoxin, brevetoxin, and domoic acid and have identified toxin-specific electrophysiological signatures for each. Brevetoxin (PbTX3, 50-200 nM) produced a significant reduction in orthodromic population spike amplitude which was quick to reverse during a 50 min wash-out, while antidromic population spikes and field EPSPs exhibited only slight reductions, and fibre spiof orthodrokes showed no change at all. Domoic acid (100 nM) produced a robust, reversible increase in amplitude mic spikes, and the appearance of multiple spikes (i.e., epileptiform activity) within minutes of toxin wash-in. Other notable features of the domoic acid signature included a significant decrease in amplitude of the field EPSPs, and a complete absence of effect on either antidromic or fibre spikes. Fifty nanomolar saxitoxin (PSP) abolished all responses in all slices. Only antidromic spikes showed any recovery during wash-out. Field EPSP and fiber spike analysis further demonstrated that the preparation is capable of reliably detecting saxitoxin in a linearly responsive fashion at toxin concentrations of 25-200 nM, and tests of naturally contaminated shellfish confirmed the utility of this assay as a screening method for PSP. Our findings suggest that the in vitro hippocampal slice preparation has potential in the detection and analysis of three marine algal toxins important to the shellfish industry.

Animals↗
PubMed1973

Influence of B locus blood groups on adult mortality and egg production in the White Leghorn chicken.

The influence of the B locus blood group on adult viability and egg production was studied in two White Leghorn populations (S1 and S2) synthesized from inbred line crosses. Each line segregated for four B alleles. Four homozygotes and six heterozygotes were produced in each line over a five-year period, and for an additional three years tests on certain blood-group combinations were continued. A total of 4371 birds were included in the study. Greatest differences in blood groups were found in the S1 line, with the B(2) and B(21) alleles seemingly having favorable effects and with B(1) having unfavorable effects. The B(1) homozygote was consistently the lowest in egg production (53.2%) and highest adult mortality (40.4%). The relative spread in standard deviation units between the B(1) and B(2) homozygotes was more than three times greater in adult mortality than in egg production; B(2) was incompletely dominant to B(1). Within the S1 line, the superiority of the heterozygotes was mainly a consequence of the poor fitness of the B(1) homozygote, suggesting that in a random-mated population B(1) would be maintained only by mutation and not by a polymorphic mechanism.-Over the eight years of the experiment, adult viability of the B(1) homozygote improved 4.4% per year (P<0.05). Assuming this regression results from natural selection, either of two hypotheses can account for the results: (1) The B locus is pleiotropic with natural selection for many B modifiers, and (2) the B locus is neutral but linked to a major fitness locus.

Analysis of Variance↗