Multicentre evaluation of glycated haemoglobin (HbA1c) of Roche Diagnostics in Andalusia

Background

A Spanish multicentre evaluation of the third generation of Roche Diagnostics immunoturbidimetric inhibition method (TINIA) is presented for quantification of haemoglobin A1c (HbA1c) in whole blood.

Methods

The analytical performance of the TINIA test was evaluated and blood sample results were compared with two other widely used analysers, Bio-Rad Variant II and Adams Arkray HA-8160, based on HPLC.

Results

Within- and between-batch imprecision (coefficients of variation (CVs)) for HbA1c levels of 5, 6, 7 and 8% were 0.77, 1.23, 1.35 and 1.26% and 2.38, 1.51, 1.76 and 2.16%, respectively. For low (5.4% A1c) and high (10.1% A1c) quality control samples, the within and between-batch %CV were: 1.26; 1.43 and 2; 1.71 respectively. The test met the expected performance in most aspects, except for linearity, that is under the reported range, and HbF interferences, detected for levels over 7.5%. There was a good concordance between the results of TINIA and Variant-IIt in the whole range and with HA-8160 only up to levels of 9%. Between-batch imprecision suggests more frequent calibrations than reported by the provider to maintain variability within the limits established by clinical practice guidelines.

Conclusions

The assay meets the necessary quality standards for routine use, as long as we keep the analytical variability within narrow limits. The results may be interchangeable with the tested HPLC systems, but HbF interference is not detected and it happens at lower levels than reported.     

Accuracy of cone beam computed tomography–derived casts: A comparative study

Statement of problemThe accuracy of the external surface and internal trabecular architecture of large cone beam computed tomography (CBCT)–derived dentomaxillofacial anatomic casts has not yet been thoroughly investigated.PurposeThe purpose of this comparative study was to evaluate the quantitative accuracy of CBCT-derived mandibular casts by applying an innovative land-mark free methodology.Material and methodsFollowing inclusion and exclusion criteria, a CBCT scan of an 18-year-old woman was acquired. The mandible was segmented and isolated from the data set. The segmented mandible included depiction of the cortical surface, trabecular architecture, erupted teeth, and impacted third molars with incomplete root formation. Fifteen mandibular casts were fabricated by using multijet (MJ=4), digital light processing (DLP=4), stereolithography (SLA=2), fused deposition modeling (FDM=2), colorjet (CJ=2), and selective laser sintering (LS=1)-based high-quality medical commercial and office printers. Each printed cast was scanned and superimposed onto the original mandible, and the accuracy of the complete mandible and individual surfaces were assessed with a color-coded map.ResultsWhen the overall combined error associated with complete casts based on printing technology were compared, MJ showed the highest accuracy (0.6 ±0.7 mm). FDM technology (2.2 ±3.4 mm) had the highest overall absolute mean difference. No significant difference was observed when both individual surfaces and the complete mandible were compared.ConclusionsOverall, casts replicated the skeletal and dental anatomic surfaces well. However, shortcomings were observed in relation to depicting trabecular architecture.     

Neuroprotective effects of the agonist of metabotropic glutamate receptors ABHxD-I in two animal models of cerebral ischaemia

The neuroprotective efficacy of 2-aminobicyclo[2.1.1]hexane-2,5-dicarboxylic acid-I (ABHxD-I), a rigid agonist of metabotropic glutamate receptors, was studied using a 3-min global cerebral ischaemia model in Mongolian gerbils and the hypoxia/ischaemia model in 7-day-old rats. The effects on brain damage of ABHxD-I (30 mg/kg, intraperitoneally or 7.5 microg intracerebroventricularly) administered 30 min before global ischaemia or 30 min after hypoxia/ischaemia was evaluated 14 days after the insults. Treatment of adult gerbils with ABHxD-I injected i.c.v. but not systemically, prevented post-ischaemic hyperthermia and substantially reduced brain damage. These effects may reflect low permeability of the adult blood-brain barrier to ABHxD-I, and the role of reduced body and brain temperature in neuroprotection after its i.c.v. administration. ABHxD-I given either i.p. or i.c.v. to developing rats reduced brain damage by 55 and 37%, respectively, without affecting the body temperature. Due to immaturity and increased post-ischaemic permeability of the blood-brain barrier in developing rats, ABHxD-I may induce neuroprotection by direct interference with brain metabotropic glutamate receptors.     

Changes in the NPY immunoreactivity in gerbil hippocampus after hypoxic and ischemic preconditioning

Preconditioning with sublethal ischemia or hypoxia may reduce the high susceptibility of CA1 pyramidal neurons to ischemic injury. In this study, we tested the hypothesis that enhanced level of neuropeptide Y (NPY) might play a role in the mechanisms responsible for this induced tolerance. Changes in NPY immunoreactivity in the hippocampal formation of preconditioned Mongolian gerbils were compared with the level of tolerance to test ischemia. Tolerance was induced by preconditioning with 2-min of ischemia or with three trials of mild hypobaric hypoxia (360 Torr, 2 h), separated by 24 h, that were completed 48 h before the 3-min test ischemia. The number of NPY-positive neurons in the gerbil hippocampal formation was assessed 2, 4 and 7 days after preconditioning. Survival of the CA1 pyramidal neurons was examined 14 days after the insult. Our experiments demonstrated that ischemic and hypoxic preconditioning produced equal attenuation of the damage evoked by 3-min ischemia, although the pattern of NPY immunoreactivity in the hippocampus differed. Preconditioning ischemia resulted in a 20% rise in the number of NPY-positive neurons 2 days later that disappeared 4 days after the ischemic episode, while mild hypobaric hypoxia induced a twofold increase in the number of NPY-positive neurons that lasted for at least 7 days. Although induced tolerance to ischemia 2 days after ischemic or hypoxic preconditioning was accompanied by increased immunoreactivity of NPY, there was no correlation between its intensity and the level of neuroprotection.     

Pharmacological activity of calcimimetic NPS R-568 administered intravenously in rats: dose dependency

Calcimimetics administered orally cause "pharmacological parathyroidectomy" confirmed by a decrease in parathyroid hormone secretion (PTH) and in plasma Ca(2+) concentration. Parathyroids are also the source of parathyroid hypertensive factor (PHF). The aim of this study was to determine the dose-dependent effect of an intravenously (iv) applied calcimimetic, NPS R-568, on plasma Ca(2+) concentration, urinary phosphate excretion and mean arterial blood pressure (MAP) in rats. Clearance experiments were performed on male Wistar rats anesthetized with thiopental and infused iv with saline supplemented with (3)H inulin for glomerular filtration rate (GFR) determination. NPS R-568 was administered iv as a bolus at the doses: 0.5, 1.0, 2.5 and 5.0 mg/kg. Control group of rats received vehicle only. MAP was monitored continuously in the carotid artery. Urine was collected from cannulated urinary bladder. NPS R-568 applied iv dose-dependently decreased plasma Ca(2+) and fractional phosphate excretion (FE(Pi)). In the control group, no significant changes in plasma Ca(2+) and FE(Pi) were observed. The most efficient hypotensive effect vs. control group was induced by the NPS R-568 of a dose of 1.0 mg/kg. Our results indicate that the dose of 1 mg/kg of the calcimimetic NPS R-568 administered iv is sufficient to induce the decrease in plasma Ca(2+) and urinary phosphate excretion accompanied with hypotensive effect in Wistar rats.