The olfactory responses of the antenna and maxillary palp of the fleshfly, Neobellieria bullata (Diptera: Sarcophagidae), and their sensitivity to blockage of nitric oxide synthase.

The relative sensitivities of the olfactory receptors in the antenna and maxillary palp of the fleshfly, Neobellieria bullata, were assessed using simultaneous electroantennograms (EAGs) and electropalpograms (EPGs). In general, the antennae and maxillary palps were more sensitive to odors related to animals (blood extract and saturated carboxylic acid) than to odors that were plant-derived (citral, hexenol, hexenal). In addition, the maxillary palps were relatively less sensitive to plant-derived odorants than the antennae, perhaps related to their anatomical position. Scanning electron microscopy was also used to assess the types of sensilla found on the two organs. In addition, NADPH-diaphorase histochemistry was used in an attempt to localize the enzyme nitric oxide synthase (NOS) in the antenna and the maxillary palps. We found evidence of NADPH-diaphorase staining in both organs, with localized staining in the antennal cells and more general staining in the maxillary palps. When NOS was selectively blocked using the antagonist L-NAME, the amplitude of the EAGs and EPGs to odorants fell by 30-50%. In contrast, application of the inactive enantiomer, D-NAME, did not change the amplitude of the EAGs or the EPGs. Our results indicate that NOS is involved in the function of olfactory receptor cells in the fleshfly.

Investigation of an occupational cancer cluster using a population-based tumor registry and the National Death Index.

Occupational physicians investigate perceived cancer clusters to alleviate employee concerns and pursue etiologic hypotheses. We conducted a retrospective cohort analysis of all past and present employees of a metal fabrication plant and a comparison plant after employees recognized five cancer cases in 1987. We ascertained cases of all subjects who were employed at some time in the 8 years before 1987 through the Colorado Central Cancer Registry and determined vital status through the National Death Index. Cancer incidence at the index plant was almost identical to that of the population of the Denver metropolitan area (standardized incidence ratio [SIR] = 99, 95% confidence interval [CI] 59-165). Proportional incidence ratios revealed that no type of cancer occurred with significant excess in the index plant population during 1979 through 1986. Where population-based tumor registries exist, occupational physicians can employ this inexpensive and robust methodology to assess cancer incidence in exposed cohorts, pursue exposure-response relations, and evaluate clusters.

Labeling of Rh antibodies on solid-phase protein A.

Rh0(D) antibodies which retain immune specificity after radiolabeling were prepared by a procedure which does not require IgG isolation from serum, requires 10-fold less isotope than conventional techniques and yields antibody solutions of defined composition. The method involves radioiodination of IgG on immobilized protein A, depends on employing human red cells reduced in surface cytophilic IgG, and exploits the inability of goat IgG to interact with Staphylococcus aureus protein A. The technique concentrates IgG by affinity adsorption and should prove useful in preparing radiolabeled alloantibodies from dilute human antisera and for red cell autoantibodies.