Evaluation of point-of-care maternal glucose measurements for the diagnosis of gestational diabetes mellitus.

OBJECTIVE: Using updated laboratory standards as the reference, we aimed to compare point-of-care (POC) maternal capillary glucose testing with the diagnostic accuracy of reference and customary venous samples. DESIGN, SETTING, POPULATION: Women screened selectively with a one-step 75-g oral glucose tolerance test (OGTT) at 24-28 weeks' gestation were conveniently recruited to this prospective observational study. METHODS: Two venous samples and one capillary sample were taken at each OGTT time point. Venous sample one was a fluoride-EDTA (FE) tube placed on an ice-slurry until cell separation and analysis within 30 minutes (reference standard). Venous sample two was transported in a tube containing FE (without ice) (customary practice). A capillary sample was used for POC testing. Various cut-off points for the POC sample were examined to evaluate diagnostic accuracy. MAIN OUTCOME MEASURES: The sensitivity, specificity, positive and negative predictive values and accuracy of POC capillary glucose for the diagnosis of GDM. RESULTS: Of 108 women, GDM was detected in 47.2% (n = 51), 17.6% (n = 19) and 24.1% (n = 26) using the reference standard, customary practices and POC, respectively (P < 0.001). However, based on adjustment of the POC fasting diagnostic threshold from ≥5.1 to ≥4.8 mol/l (aPOC), sensitivity, specificity, PPV, NPV and accuracy improved to 92.5, 76.5, 69.8, 94.5 and 94.5%, respectively. CONCLUSIONS: POC capillary maternal glucose tests were superior to customary laboratory practices for diagnosing GDM. This has considerable potential, particularly in healthcare settings where facilities for phlebotomy are distant from the laboratory or pre-analytical sample handling is substandard. TWEETABLE ABSTRACT: Adjusted point-of-care glucose measurements have potential in the diagnosis of gestational diabetes mellitus.

Determining Emplacement Conditions and Vent Locations for Channelized Lava Flows Southwest of Arsia Mons.

The lava flow field southwest of Arsia Mons, Mars has complex volcanic geomorphology. Overlapping flows make observations of their total lengths and identification of their source vents impossible. Application of flow emplacement models, which rely upon physical parameters such as flow length, using only the exposed flow may produce inaccurate estimates of effusion rate, viscosity, and yield strength. We use an established terrestrial thermorheological model (PyFLOWGO), modified to Mars conditions, to estimate effusion rates, viscosities, yield strengths, and possible vent locations for five Mars flows. Our investigation found a range of effusion rates from 2,500 to 6,750 m3 s-1 (average of ∼4,960 m3 s-1). These results are an order of magnitude higher than terrestrial channelized basaltic flows. Corresponding modeled viscosities and yield strengths ranged from 9.4 × 103 to 6.6 × 105 Pa s (average of 5.5 × 104 Pa s) and 66 to 381 Pa (average of 209 Pa), respectively. A novel secondary application of PyFLOWGO that assumes upslope channel narrowing provided estimates of the entire channel length, which is on average four times longer than the exposed portions. Projecting these lengths upslope shows that four of the five flows may have a common vent location, which shares morphologic similarities to other Tharsis region vents. This modeling approach for partially-exposed lava flows makes it possible to not only determine eruptive parameters, but also to estimate total channel lengths and thereby identify possible source vents.

Some kinetic properties of pyruvate kinase from Trypanosoma brucei: influence of pH and fructose-1,6-diphosphate.

The influence of pH on the activity of purified pyruvate kinase (ATP:pyruvate 2-O-phosphotransferase, EC 2.7.1.40) from Trypanosoma brucei has been studied. The Km for the coenzyme ADP is pH-dependent and shows the involvement of a dissociable group on the free enzyme with a pKa of 6.5-6.7. The cooperative interaction of the multiple phosphoenolpyruvate (PEP) binding sites is independent of pH in the range of 5.7-7.8. Variation of the Vmax value with pH indicates the presence of a dissociated group (pKa 6.2-6.3) and of an undissociated group (pKa 7.5-7.6) in the enzyme-substrate complex. A doubly dissociated phosphate group on PEP is shown to be essential by the effects of pH on the S0.5 value for this substrate, as is an undissociated enzyme group with a pKa in the range 6.7-7.0. It is shown that PEP and frucotse-1,6-diphosphate (FDP) act entirely in conjunction in allosterically activating the enzyme, FDP, the heterotropic effector, decreases the interaction between PEP binding sites at low concentration, and decreases the S0.5 value for PEP at higher concentration. A model for the interaction of the enzyme with its substrates is discussed.

13C nuclear magnetic resonance studies of anaerobic glycolysis in Trypanosoma brucei spp.

Anaerobic glycolysis in Trypanosoma brucei spp. has been studied by 13C NMR at 50 and 75.5 MHz. The uptake of [U-13C]glucose by cell suspensions of T. b. brucei was monitored by time-course spectroscopy, and while no anomeric specificity was found, the end-products of glycolysis were confirmed as glycerol and pyruvate together with alanine and dihydroxypropionate. The intermediacy of L-glycerol-3-phosphate was also ascertained. The incorporation of C-1 of [1-13C]glucose and of C-6 of [6-13C]glucose into glycerol and pyruvate in T. b. gambiense was quantified by measurement of the longitudinal relaxation times of the species involved. An incorporation to the extent of 66% of each substrate into equimolar amounts of glycerol and pyruvate indicate that Keq for the triosephosphate-isomerase-mediated reaction approaches unity.

Intravenous immunoglobulin for the treatment of Kawasaki disease in children.

BACKGROUND: Kawasaki disease is the most common cause of acquired heart disease in children in developed countries. The coronary arteries supplying the heart can be damaged in Kawasaki disease. The principal advantage of timely diagnosis is the potential to prevent this complication with early treatment. Intravenous immunoglobulin (IVIG) is widely used for this purpose. OBJECTIVES: The objective of this review was to evaluate the effectiveness of IVIG in treating, and preventing cardiac consequences, of Kawasaki disease in children. SEARCH STRATEGY: Electronic searches of the Cochrane Peripheral Vascular Disease Group Specialised Register, CENTRAL, MEDLINE, EMBASE, and CINAHL were performed (last searched April 2003). We also searched references from relevant articles and contacted authors where necessary. In addition we contacted experts in the field for unpublished works. SELECTION CRITERIA: Randomised controlled trials of intravenous immunoglobulin to treat Kawasaki disease were eligible for inclusion. DATA COLLECTION AND ANALYSIS: Fifty-nine trials were identified in the initial search. On careful inspection only sixteen of these met all the inclusion criteria. Trials were data extracted and assessed for quality by at least two reviewers. Data were combined for meta-analysis using relative risk ratios for dichotomous data or weighted mean difference for continuous data. A random effects statistical model was used. MAIN RESULTS: The meta-analysis of IVIG versus placebo, including all children, showed a significant decrease in new coronary artery abnormalities (CAAs) in favour of IVIG, at thirty days RR (95% CI) = 0.74 (0.61 to 0.90). No statistically significant difference was found thereafter. A subgroup analysis excluding children with CAAs at enrollment also found a significant reduction of new CAAs in children receiving IVIG RR (95%) = 0.67 (0.46 to 1.00). There was a trend towards benefit from IVIG at sixty days (p=0.06). Results of dose comparisons showed a decrease in the number of new CAAs with increased dose. The meta-analysis of 400 mg/kg/day for five days versus 2 gm/kg in a single dose showed statistically significant reduction in CAAs at thirty days RR (95%) = 4.47 (1.55 to 12.86). This comparison also showed a significant reduction in duration of fever with the higher dose. There was no statistically significant difference noted between different preparations of IVIG. There was no statistically significant difference of adverse effects in any group. REVIEWER'S CONCLUSIONS: Children fulfilling the diagnostic criteria for Kawasaki disease should be treated with IVIG (2 gm/kg single dose) within 10 days of onset of symptoms.

Three methods of taking the brachial systolic pressure to measure the ankle/brachial index: which one is best?

This study was designed to determine which method of measuring the brachial systolic blood pressure is most accurate when determining the ankle/brachial index (ABI). The accuracy of the stethoscope diaphragm was compared with the accuracy of the stethoscope bell and Doppler methods in measuring the brachial systolic pressure. These pressures were used in the calculation of the ABI, and then the ABI was compared by method and time since surgery. The sample consisted of 31 subjects who had peripheral arterial bypass surgery. The findings of this study indicate that there is no significant difference in the ABI when the brachial systolic blood pressure is measured by any of the three methods. A difference was found between the right-arm and left-arm brachial systolic pressures in many of the patients, and this would make a difference in the calculation of the ABI.