Background: We evaluated a new, 2-min blood creatinine method using the hand-held i-STAT analyzer. Good results have already been reported using this analyzer for 10 methods including electrolytes, TCO₂, pH, PCO₂, bicarbonate, glucose, hemoglobin and urea for uremic blood, hemodialysate and peritoneal effluent. Methods: Evaluation included study of imprecision and accuracy. Results: Imprecision studies gave excellent results, including those for reproducibility of 6 solutions with a mean of 10 repeats and coefficients of variation (CVs) of 0.4–3.4%, and also the mean of the differences between 33 duplicate blood specimens which was 2.2% of the specimen mean. To assess accuracy, we compared results of 149 tests by i-STAT and Beckman Synchron CX7 methods. The difference between the two means was 2.6% and the mean of all differences was 10.9% with i-STAT results higher, especially when blood creatinine values were <100 µmol/l (1.1 mg/dl) indicating the need for a slightly higher upper limit of the normal range. The correlation coefficient between the two methods was 0.99, the slope 1.0 and the intercept –5.0 µmol/l (–0.06 mg/dl). We assessed the recommended creatinine correction for variation in PCO₂ above and below 40 mm Hg, but our results did not suggest the need for such a correction in our range of 27–64 mm Hg; omission would remove a major method disadvantage. Assays of hemodialysate and peritoneal effluent were also satisfactory. Conclusions: The i-STAT creatinine method is simple and rapid and our evaluation showed satisfactory accuracy and precision. However, results were on average slightly higher than for the Beckman Synchron CX7 method.

Several studies suggest that anthocyanin intake could modify risk factors for metabolic syndrome. Blueberries are a rich, whole‐food source of anthocyanins. We tested the effect of a semi‐purified diet with added whole blueberry powder (2% w:w) or a carbohydrate‐matched control diet on factors of metabolic syndrome in the obesity‐prone Zucker Fatty rat, fed either a low fat (10% fat) diet or a high fat (45% fat) diet. After 90 days, both the low fat blueberry (LFB) and high fat blueberry (HFB) groups had reduced abdominal fat compared to controls, and the LFB group had reduced body weight and % fat mass. Both LFB and HFB groups had significantly reduced triglycerides, total cholesterol, fasting insulin, and fasting glucose. LFB and HFB also had improved glucose clearance, as measured by a glucose tolerance test. Given the improved glucose control, we then measured mRNA transcripts in skeletal muscle and retroperitoneal fat related to glucose and lipid uptake and metabolism by PCR Array. The results suggest that regular intake of blueberry reduced several key risk factors for cardiovascular disease and metabolic syndrome. Furthermore, these benefits were augmented when fed a low fat diet. Finally, blueberry diet conferred tissue changes in several genes related to lipid and glucose metabolism, which could support the in vivo results of greater insulin sensitivity and reduced fat accumulation.

Increased fruit and vegetable intake can reduce hypertension, but its effect upon hypertensive cardiac pathology is unknown. This relationship was tested in the Dahl‐Salt Sensitive rat fed a high‐salt diet. Provision of 3% (w:w) whole table grape powder for 18 weeks reduced blood pressure, reduced cardiac hypertrophy, improved cardiac function, and increased cardiac glutathione, a key endogenous antioxidant. Provision of vasodilator hydralazine matched the blood pressure reduction of grape but failed to similarly reduce cardiac pathology. In vitro, phytochemicals found in grapes can alter genes related to Phase I/II metabolism, impacting glutathione dynamics. However, cardiac effects with a whole food are unknown. RT‐PCR analysis indicated that grape provision altered genes for oxidoreductases, transferases, sulfotransferases and peroxidases which affect glutathione dynamics, which on balance, would favor elevated glutathione. Key expression changes are confirmed by immunoblot. Importantly, these changes were conserved in grape‐fed, healthy (low‐salt fed) rats, further supporting the nutrigenomic effects of grape intake. In conclusion, physiologically relevant phytochemical intake reduced hypertensive cardiac pathology and altered cardiac transcripts related to glutathione dynamics, which may be vital to its cardioprotective effects. California Table Grape Commission, NIH‐NHLBI.Grant Funding SourceNIH‐NHLBI, California Table Grape Commission