Faculty Bibliography

The effect of the stress of crowded housing conditions (10 mice/cage) on the onset of diabetes after multiple, sub-diabetogenic doses of streptozotocin (MSZ) in male C57BL/KsJ mice was investigated. Prior to MSZ treatment, the group-housed and individually-housed animals had similar plasma glucose levels, while the former group's plasma corticosterone (CS) levels were elevated (54 +/- 8 ng/ml, p less than 0.03; 166% of the latter group). The group-housed animals became hyperglycemic (253 +/- 23 mg/dl) 2 days after the MSZ (day 7), with maximum hyperglycemia (506 +/- 23 mg/dl) developing by day 10. The individually housed animals did not become hyperglycemic until day 10 (303 +/- 24 mg/dl, p less than 0.001), and did not reach maximal hyperglycemia until between days 31 and 46, when plasma glucose levels were no longer different from the group-housed mice (507 +/- 37 mg/dl). There was a significant and progressive rise in CS levels of the stressed animals, reaching 218 +/- 25 ng/ml at day 46. The rise in CS of the unstressed animals was not significant until day 46, when the mean value reached 96 +/- 19 ng/ml (p less than 0.001 vs. basal). However, even at the conclusion of the experiment, the mean CS in the stressed animals was still 227% of that in the unstressed group (p less than 0.001). These studies demonstrate that the effects of stress (biochemically documented as an increase in CS levels) act synergistically with streptozotocin to promote an earlier onset of diabetes mellitus in males of this murine strain.

We analyzed lectin binding patterns of amyloid glycoconjugates in patients with lattice dystrophy of the cornea. Results of paraffin and frozen sections differed in some instances. With paraffin sections, three lectins--wheat germ agglutinin (WGA), Ricinus communis agglutinin I (RCA-I), and concanavalin A (Con A)--stained the abnormal deposits. In frozen sections, the abnormal deposits were stained by five lectins--WGA, RCA-I, Con A, peanut agglutinin (PNA), and soybean agglutinin (SBA). In paraffin sections, PNA and SBA did not stain amyloid deposits. In both paraffin and frozen sections, some lectin-positive deposits corresponded to the Congo red-positive material, whereas others were present surrounding and encroaching on the Congo red-reactive material. This study demonstrates that WGA-, RCA-I-, Con A-, PNA-, and SBA-positive abnormal deposits are present in corneas with lattice dystrophy. Since lectins bind to specific sugar residues, we conclude that the abnormal deposits consist, at least in part, of glycoconjugates and that these glycoconjugates contain oligosaccharides with N-acetylglucosamine/sialic acid, mannose/glucose and terminal beta-galactose residues and chains with terminal beta-galactose-N-acetylgalactosamine disaccharides.