Analysis of the influence of the type of closure in the organoleptic characteristics of a red wine by using an electronic panel

An electronic panel formed by an electronic nose, an electronic tongue and an electronic eye has been successfully used to evaluate the organoleptic characteristics of red wines vinified using different extraction techniques and micro-oxygenation methods and bottled using closures of different oxygen transmission rates (OTR). The three systems have demonstrated a good capability of discrimination by means of Principal Component Analysis (PCA). Partial Least Squares Discriminant Analysis (PLS-DA) has permitted to establish prediction models based on the type of closure, the polyphenol content or the effect of micro-oxygenation. The best correlations found using the e-eye and the e-nose are related to the OTR of the closure. In contrast, the electronic tongue is more sensitive to the polyphenol content. The discrimination and prediction capabilities of the system are significantly improved when signals from each module are combined. The electronic panel can be a useful tool for the characterisation and control of oxygen and antioxidant capability of red wines.

Hypochromic reticulocytes, hypochromic erythrocytes and p-transferrin receptors in diagnosing iron-deficient erythropoiesis

BACKGROUND

The purpose of this study was to test the hypothesis that hypochromic reticulocytes, hypochromic erythrocytes and p-transferrin receptors are sensitive variables in detecting iron-deficient erythropoiesis in healthy subjects and hemodialysis patients.

METHODS

Study 1: Twenty-one blood donors donated 450 mL blood. During the following 2 weeks blood samples were analyzed for the variables mentioned above. Study 2: Twenty-eight blood donors received 10,000 U recombinant human erythropoietin (rHuEPO) twice in the first week or placebo, after they had donated 450 mL blood. During the following 3 weeks the blood samples were analyzed for the variables mentioned in Study 1. Study 3: Eighteen hemodialysis patients receiving rHuEPO and iron treatment had either iron treatment discontinued for 4 weeks, after which iron was resumed, or received unchanged treatment. During 8 weeks blood samples were analyzed for the variables mentioned in Study 1.

RESULTS

Study 1: Blood donation induced an increase in hypochromic reticulocytes of 178%, in hypochromic erythrocytes the increase was 267%, and in p-transferrin receptors 32%. Study 2: Treatment with rHuEPO induced a more pronounced increase than placebo in hypochromic reticulocytes (232% vs. 158%) and hypochromic erythrocytes (1240% vs. 300%), but not in p-transferrin receptors. Study 3: Discontinuation of iron treatment did not cause any significant differences in the variables mentioned above between the two groups, but caused a 25% decrease in p-ferritin. When iron treatment was resumed, p-ferritin increased by 19%. We found no significant changes in the control group.

CONCLUSIONS

Hypochromic reticulocytes, hypochromic erythrocytes and p-transferrin receptors are sensitive variables in the early detection of iron-deficient erythropoiesis in healthy subjects, but in this study the iron withdrawal period was too short to show the value of these variables in the detection of iron-deficient erythropoiesis in hemodialysis patients.

Evaluation of a dipstick test for glucose in urine

As an example of qualitative tests, a dipstick analysis for glucose in urine has been tested for the influence of modifying factors on the test result. Two different types of dipsticks were examined, "Clinistix" and "S-Gluko-test." Used according to manufacturer's instructions, the latter is more sensitive and selective. By multivariance analysis the following variables were examined: urine samples, inter- and intra-analyst, exposure to light, and dipstick batch. The first three contributed significantly to the total variation in results, inter-specimen variation being the most important. With knowledge of the frequency of testing urines with a given glucose concentration and the probability of the result at that concentration, an expression of the probability of the glucose content of a urine sample can be obtained. Even with the tests of the type examined having a sensitivity and specificity exceeding 95%, 14 of 100 patients suspected of having diabetes mellitus on the basis of a dipstick examination will be found to have a urinary glucose concentration of less than 2 mmol/liter. These figures were found when the prevalence of urines with a glucose concentration exceeding 2 mmol/liter was 17.5%.

Evaluation of a dipstick test for glucose in urine

As an example of qualitative tests, a dipstick analysis for glucose in urine has been tested for the influence of modifying factors on the test result. Two different types of dipsticks were examined, "Clinistix" and "S-Gluko-test." Used according to manufacturer's instructions, the latter is more sensitive and selective. By multivariance analysis the following variables were examined: urine samples, inter- and intra-analyst, exposure to light, and dipstick batch. The first three contributed significantly to the total variation in results, inter-specimen variation being the most important. With knowledge of the frequency of testing urines with a given glucose concentration and the probability of the result at that concentration, an expression of the probability of the glucose content of a urine sample can be obtained. Even with the tests of the type examined having a sensitivity and specificity exceeding 95%, 14 of 100 patients suspected of having diabetes mellitus on the basis of a dipstick examination will be found to have a urinary glucose concentration of less than 2 mmol/liter. These figures were found when the prevalence of urines with a glucose concentration exceeding 2 mmol/liter was 17.5%.