High glucose mediates prooxidant and antioxidant enzyme activities in coronary endothelial cells

Objective: Excess levels of free radicals such as nitric oxide (NO) and superoxide anion (O2-)are associated with the pathogenesis of endothelial cell dysfunction in diabetes mellitus. This study was designed to investigate the underlying causes of oxidative stress in coronary microvascular endothelial cells (CMEC) exposed to hyperglycaemia. Methods: CMEC were cultured under normal (5.5 mmol/L) or high glucose (22 mmol/L)concentrations for 7 days. The activity and expression (protein level) of eNOS, iNOS, NAD(P)H oxidase and antioxidant enzymes, namely, superoxide dismutase (SOD), catalase and glutahione peroxidase (GPx) were investigated by specific activity assays and Western analyses,respectively while the effects of hyperglycaemia on nitrite and O2 - generation were investigated by Griess reaction and cytochrome C reduction assay, respectively. Results: Hyperglycaemia did not alter eNOS or iNOS protein expressions and overall nitrite generation, an index of NO production. However, it significantly reduced the levels of intracellular antioxidant glutathione by 50% (p<0.05) and increased the protein expressions and/or activities of p22-phox, a membrane-bound component of pro-oxidant NAD(P)H oxidase and antioxidant enzymes (p<0.05). Free radical-scavengers, namely, Tiron and MPG (0.1-1 mol/L) reduced hyperglycaemia-induced antioxidant enzyme activity and increased glutathione and nitrite generation to the levels observed in CMEC cultured in normoglycaemic medium (p<0.01). The differences in enzyme activity and expressions were independent of the increased osmolarity generated by high glucose levels as investigated by using equimolar concentrations of mannitol in parallel experiments. Conclusions: These results suggest that hyperglycaemia-induced oxidative stress may arise in CMEC as a result of enhanced prooxidant enzyme activity and diminished generation of 3 antioxidant glutathione. By increasing the antioxidant enzyme capacity CMEC may protect themselves against free radical-induced cell damage in diabetic conditions. The definitive version is available at http://www.blackwell-synergy.co

SCALES: A Computer Program to Convert among Three Developmental Stage Scales for Wheat

The Haun, Feekes, and Zadoks-ChanpKonzak developmental stage scales are often used to report phenological information for wheat (Triticum aestivum L.) development. Agronomists familiar with one of these scales may have only a passing acquaintance with developmental scales other than the one they consider most appropriate for their purposes. This makes review and interpretation of the literature more difficult. Although wheat development models often report phenological results, they generally use no more than one scale. For these reasons, and because there is not a simple numeric correspondence among the three scales, a computer program to convert among them is a useful tool. SCALES is a three-module FORTRAN program that relates the three scales based on published descriptions. The interactive user interface module requests an input scale value and minimal additional information, which the conversion module uses to determine values for the remaining two scales via a dichotomous key. The output module writes the conversion results to the monitor. SCALES may be used independently for comparing phenological data based on different developmental scales, or the conversion module may be incorporated into computer models to provide output of developmental stage information for the simulation

SCALES 2: COMPUTER PROGRAM TO CONVERT AMONG DEVELOPMENTAL STAGE SCALES FOR CORN AND SMALL GRAINS

Producers and agronomists need crop developmental scales that are easy to use, universally accepted, and accurate. Development of such a scale requires correlation of stages among scales currently in use and correlation of developmental patterns among crops. A computer program for converting among staging systems is a useful tool in developing new staging systems with wider applicability. The BBCH scale (BASF-Bayer-Ciba-Geigy-Hoechst) has been proposed as a prototype of a universal scale. We have added the BBCH scale to our scale conversion program for wheat (Triticum aestivum L.) and developed a similar conversion program for corn (Zea mays L.), based on correlations reported in the literature. SCALES 2 provides a tool to translate among several widely used scales for corn and small-gain development, and can be used to develop familiarity with the various scales

Nitrogen and Dry Matter Distribution by Culm and Leaf Position at Two Stages of Vegetative Growth in Winter Wheat

Knowledge of N and assimilate partitioning in wheat (Triticum aestivum L.) improves management efficacy and crop model development. Our purpose was to describe N and dry matter distribution during vegetative growth of blades, sheaths, and internodes on four culms. Winter wheat grown at the Colorado State University Horticultural Farm was sampled at Haun Stage 5 and jointing. Samples were dried, weighed, and analyzed for N. As the canopy developed and older tissue contributed more of total tissue, N concentration decreased although N mass and dry weight increased. Dry matter and N mass decreased from MC to T1 and T2 to T11, while the reverse order was found for N concentration. Dry weight and N mass decreased as culm order increased (culm age decreased), because phyctomers were smaller and fewer existed. Nitrogen concentration had the opposite trend because new tissue contained about 40 g N kg-1 but declined as the tissue aged to 30 g N kg-1. Initial growth of all tissues had concentrations \u3e50 g N kg-1 and at senescence declined to 19 g N kg-1. Phytomer positions on different culms tended to have similar N concentrations while identical phytomers on primary tillers tended to have greater dry weights than those on the MC and secondary tillers. Phytomers tended to increase in N concentration and mass and dry weight acropetally. Results show that viewing the canopy as the interplay of appearance, growth, interaction, and senescence of culms or phytomers can increase understanding of canopy N and dry weight dynamics