Site-specific (13) С/(12) С isotope abundance ratios in dicarboxylic oxyacids as characteristics of their origin.

RATIONALE: Recommendations of relevant international organizations controlling the quality of grape wines and beverages specify that only tartaric acids of grape origin can be introduced to achieve the required parameters. The development of methods for determining the origin of tartaric acid in grape wine is of great technological significance. METHODS: Organic dicarboxylic oxyacids were extracted from wines as barium salts. Carbon dioxide, which included all the carbon atoms of the acids, was used to determine the carbon isotope ratios by Isotope Ratio Mass Spectrometry. The alkyl part of the oxyacids was burned at 560°C in the presence of air; BaCO3 containing the carboxyl carbon was left. This carbonate was used to measure the carbon isotope ratios in the carboxyl part of the acid. The carbon isotope ratios of the alkyl part of tartaric acid were found by isotope mass balance. RESULTS: The carbon isotope composition of carboxyl groups (δ(13) С values) in tartaric acid of grape (biogenic origin) had a higher (13) С content than the carbon in the alkyl part of the molecule. Tartaric acid produced by chemical synthesis (abiogenic origin) was noted to have a different (13) С/(12) С distribution: the carboxyl group of tartaric acid produced by chemical synthesis contained a smaller than or equal amount of (13) С to the alkyl part. CONCLUSIONS: This is the first determination of the site-specific distribution of the (13) С/(12) С isotopes in tartaric acids as evidence of their biogenic and abiogenic origins. The presented method for determining the origin of tartaric acid can be used for efficient control of the quality of grape wines and beverages.

Special article: evaluation of a novel noninvasive respiration monitor providing continuous measurement of minute ventilation in ambulatory subjects in a variety of clinical scenarios.

BACKGROUND: Currently there is no technology that noninvasively measures the adequacy of ventilation in nonintubated patients. A novel, noninvasive Respiratory Volume Monitor (RVM) has been developed to continuously measure and display minute ventilation (MV), tidal volume (TV), and respiratory rate (RR) in a variety of clinical settings. We demonstrate the RVM's accuracy and precision as compared with a standard spirometer under a variety of clinically relevant breathing patterns in nonintubated subjects. METHODS: Thirty-one voluntary subjects completed the primary study. MV, TV, and RR measurements were collected from the RVM and spirometer simultaneously for each participant on day 1 and day 2 and analyzed to determine accuracy, precision, and bias for normal, fast, slow, irregular, and closed-glottis breathing. RESULTS: Data demonstrated that RVM and spirometer measurements of MV and TV are equivalent in a wide range of ambulatory subjects with an average error <10% (95% confidence interval for accuracy <16%, precision <12%, and bias <11%). Repeated measures analysis of variance found no significant difference between spirometry and RVM individual measurements of MV, TV, and RR (P > 0.7), whereas a paired-difference equivalent test demonstrated, with 99% power, that both MV and TV measurements from the 2 devices are equivalent within ±15%. CONCLUSIONS: This study demonstrates RVM's clinically relevant accuracy and precision in measuring MV, TV, and RR over a 24-hour period and during various breathing patterns.

The use of medical hyperspectral technology to evaluate microcirculatory changes in diabetic foot ulcers and to predict clinical outcomes.

OBJECTIVE: Foot ulceration is a serious complication of diabetes, and new techniques that can predict wound healing may prove very helpful. We tested the ability of medical hyperspectral technology (HT), a novel diagnostic scanning technique that can quantify tissue oxy- and deoxyhemoglobin to predict diabetic foot ulcer healing. RESEARCH DESIGN AND METHODS: Ten type 1 diabetic patients with 21 foot ulcer sites, 13 type 1 diabetic patients without ulcers, and 14 nondiabetic control subjects were seen up to 4 times over a 6-month period. HT measurements of oxyhemoglobin (HT-oxy) and deoxyhemoglobin (HT-deoxy) were performed at or near the ulcer area and on the upper and lower extremity distant from the ulcer. An HT healing index for each site was calculated from the HT-oxy and -deoxy values. RESULTS: Hyperspectral tissue oxygenation measurements observed changes in tissue immediately surrounding the ulcer when comparing ulcers that heal and ulcers that do not heal (P < 0.001). The sensitivity, specificity, and positive and negative predictive values of the HT index for predicting healing were 93, 86, 93, and 86%, respectively, when evaluated on images taken at the first visit. Changes in HT-oxy among the three risk groups were noted for the metatarsal area of the foot (P < 0.05) and the palm (P < 0.01). Changes in HT-deoxy and the HT healing index were noted for the palm only (P < 0.05 and P < 0.01, respectively). CONCLUSIONS: HT has the capability to identify microvascular abnormalities and tissue oxygenation in the diabetic foot and predict ulcer healing. HT can assist in the management of foot ulceration.