The breath print represents a novel biomarker of malnutrition in pulmonary arterial hypertension: A proof of concept study.

Background: The breath print is a quantitative measurement of molecules in exhaled breath and represents a new frontier for biomarker identification. It is unknown whether this state-of-the-art, noninvasive method can detect malnutrition. We hypothesize that individuals with malnutrition will present with a distinguishable breath print.

Alterations in ascorbic acid transport into the lens of streptozotocin-induced diabetic rats and guinea pigs.

High ascorbic acid (AA) levels in the aqueous humor and intraocular tissues, including the lens, are thought to protect against the harmful effects of photochemical and ambient oxidation reactions involving oxygen and its radicals. In addition, AA may have various metabolic functions, including structural collagen formation in intraocular tissues. Recent work showed that, in the guinea pig, reduced AA was concentrated in the aqueous and lens epithelium.

Decreased ascorbic acid entry into cornea of streptozotocin-diabetic rats and guinea-pigs.

High L-ascorbic acid (AA) levels in aqueous humor and intraocular tissues including lens and cornea are thought to protect against the harmful effects of the photochemical and ambient oxidation reactions involving oxygen and its radicals. Our pulse-chase studies follow a bolus of radiolabeled test molecules including [14C]L-ascorbic acid and [3H]L-glucose (L-glu) introduced into the blood at time t = 0, and determine the time-dependent concentrations of these labeled molecules as they move into aqueous humor, corneal endothelium and stroma tissues. Calculated entry and exit rate constants provide a representative measure of the functional state of passive and carrier mediated transport mechanisms in situ in normal and diabetic animals.

Ascorbic acid entry into cornea of rat and guinea pig.

The transport rates of radiolabeled ascorbic acid (AA), 3-O-methyl-D-glucose (mD-glu) and L-glucose (L-glu) from blood into the aqueous humor, corneal endothelium, and stroma compartments were studied in male Sprague-Dawley rats and English short-haired guinea pigs. In vivo pulse chase kinetic studies supplied transport entry rate constants, Ki (min-1), and used L-glu as a passive internal control. Results in the rat indicate that AA enters the aqueous humor at rates similar to L-glu and likely via simple passive diffusion.

In vivo use of neutral radiolabelled molecular probes to evaluate blood-ocular barrier integrity in normal and streptozotocin-diabetic rats.

Evidence suggests that the consequences of diabetes mellitus are numerous and that net changes in ocular barrier permeability are necessarily complex functions of changes at specific anatomical loci. In this study we explore changes in blood-aqueous and vitreous permeability in streptozotocin-diabetic rats using five stable radiolabelled probes. Three probes, (3H)-L-glucose, (14C)-sucrose and (14C)-carboxylinulin are relatively large molecules and are expected to move into ocular humours via paracellular routes.