This study compares tear glucose dynamic differences between 121 diabetic and nondiabetic subjects after the administration of a carbohydrate load. A quantitative chromatographic analysis of tear glucose was used and the values correlated to blood glucose values. Diabetic and nondiabetic tear glucose mean values were 0.35 +/- 0.04 mmol/L and 0.16 +/- 0.03 mmol/L, respectively. Significant differences were observed among the subject groups in both the tear and capillary blood glucose values. A correlation between tear glucose and capillary blood glucose was observed. The concentration of glucose in the tear fluid changes proportionately with respect to capillary blood glucose after a carbohydrate challenge. Although it is possible to determine the diabetic status of a subject using tear glucose values alone, in the clinical setting this may not prove to be practical due to technical limitations.

MAs are powerful tools for differential screening of tears for large numbers of trace proteins. Analysis allowed the identification of previously undetected proteins that may participate in the host defense system as well as demonstrated the profound change in tear composition associated with prolonged eye closure in a manner reflective of physiological function.

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SUMMARYIn liie activated complement system, vitronectin (complement S-protcin) occupies ihe metastabie membrane binding site of the nascent precursor compiex C5b-7, so that the newly formed SC5b-7 is unable to insert into celi membranes. Some evidence also indicates that vitronectin limits on-going membrane-associated pore ibrmation by inhibiting C9 poiynierization. It has been assumed that these two stages of terminal complement complex (TCC) inhibition taice piace through charge interactions between the heparin-binding region of vitronectin and homoiogous cysteine-rich sequences of the late complement proteins C6, C7, C8 and C9. We examined SC5b-7 formation and inhibition of C9 binding in the TCC using separate haemolylie assays. The mode of action of vitronectin in these assays was compared with iwo 15mer peptides which span residues .148-379 of ihe heparin-binding region, and a heparin-atlinity polypeptide. protamine sulphate. The results showed that vitronectin acts predominantly through SC5b-7 production with a lesser effect on the inhibition of C9 lytic pore formation, in contrast, protamine suiphate did not prevent C5b-7 membrane attachment, but was a potent inhiiiitor of C9-mediated lysis. The peptides did not inhibit C5b-7 membrane insertion and only one aiTeeted C9 binding. These data suggest that the two stages of TCC inhibition involve separate binding sites on the vitronectin molecule. The site for association with nascent C5b-7 is unknown, whereas inhibition of C9 binding and pore formation taices place through the heparin-binding region.