1,721,027 research outputs found
Impact of measurement error of plasma glucose on clinical classification: a simulation analysis
Full text linkLinking lactate dehydrogenase to the severity of COVID-19 cannot ignore the employed methodology
No full textThe effects of strontium on skeletal development in zebrafish embryo
No full textThe strontium is an alkaline earth metal found in nature as trace element. Chemically similar to calcium, it is known to be involved in the human bone mineral metabolism. The strontium ranelate has been approved in therapy as drug with both anti-resorption and anabolic effects on bone tissues. Since few data in vivo are available, we used Danio rerio as animal model to evaluate the effects of strontium on skeletal development. First, toxicity assay performed on zebrafish embryos estimated the LC50 around 6. mM. Since several zebrafish bones are formed from cartilage mineralization, we evaluated whether strontium affects cartilage development during embryogenesis. Strontium does not perturb the development of the cartilage tissues before the endochondral osteogenesis takes place. About the mineralization process, we evidentiated an increase of vertebral mineralization respect to controls at lower strontium concentrations whereas higher concentration inhibited mineral deposition in dose dependent fashion. Our results evidentiated, in addition, that the calcium/strontium rate but not the absolute level of strontium modulates the mineralization process during embryonic osteogenesis.Zebrafish represents an excellent animal model to study the role of micronutrients in the development of the tissues/organs because the ions are not absorbed by intestine but assumed by skin diffusion
Models 1b and 2 according to EFLM consensus conference give the same specification for allowable total error (TEA) of plasma glucose measurement
Full text linkHeparinate but not serum tubes are susceptible to hemolysis by pneumatic tube transportation
No full textBackground: Pneumatic tube transportation (PTT) may induce hemolysis (H) in blood samples. We aimed to compare the H degree before and after PTT implementation in our hospital. Methods: Hemolysis indices (HI) for all lithium-heparin plasma samples (P) drawn by the Emergency Department in 2-month periods were retrospectively collected and pre- (n=3579) and post-PTT (n=3469) results compared. The impact of PTT introduction was investigated on LDH [HI threshold (HIt), 25], conjugated bilirubin (cBIL) (HIt, 30), K (HIt, 100) and ALT (HIt, 125). In addition, HI retrieved for P and paired serum samples collected in silica clot activator tubes (S) from the same venipuncture were compared in pre- (n=501) and post-PTT (n=509) periods. Results: Median (5-95th percentile) HI in P was significantly higher in post-PTT period [7 (0-112) vs. 6 (0-82), p<0.001]. Results reported as 'Hemolysis' in P increased from 6.6% in pre-PTT to 9.4% in post-PTT (p<0.001). Investigated tests gave the following rejection rates (pre-PTT vs. post-PTT): LDH, 13.4% vs. 18.8%, p<0.001; cBIL, 9.4% vs. 27.0%, p<0.05; K, 3.7% vs. 5.6%, p<0.001; ALT, 2.9% vs. 4.4%, p<0.01. The slightly higher susceptibility to H of S compared to paired P found in the pre-PTT [9 (1-64) vs. 6 (0-85)] was not confirmed in the post-PTT period [7 (0-90) vs. 8 (1-72)], in which median HI in S was significantly lower (p<0.001) than in pre-PTT. Conclusions: In our setting PTT promotes H in P, increasing the rate of rejected tests. The use of S appears to protect against the hemolysing effect of PTT
Impiego dell’indice itterico come esame di primo livello per l’identificazione dei campioni con concentrazioni anormali di bilirubinemia
No full textSuitability of icteric index (II) as front-line test for the identification of blood samples with abnormal total bilirubin (TB) concentrations. The use of II as a front-line test for the preliminary identification of blood samples with abnormal TB concentrations was recently proposed. However, laboratories should validate this approach on their own analyzers. In this study we validated the diagnostic accuracy of II on the Abbott Architect c16000 platform. TB concentrations (diazo-based colorimetric assay) and corresponding II values (derived from absorbance measurements of samples diluted with saline) in heparinised plasma and serum samples were collected for a 3-month period. Linear regression analysis (LRA) (II vs. TB) was performed for both samples. The diagnostic performance of II to discriminate between abnormal (>1.2 mg/dL) and physiological TB concentrations was evaluated using the ROC curve analysis. The optimal II cut-off was selected at a negative predictive value (NPV) >99% for detection of abnormal TB values. TB and relative II were obtained from 18,486 serum and 3700 plasma samples.
LRA showed a strong correlation between II and TB (serum: r2=0.951; plasma: r2=0.941). ROC curve analysis gave the following areas under the curve: serum, 0.948 (CI: 0.945-0.951), and plasma, 0.922 (CI: 0.913-0.930), showing the high accuracy of II for detecting abnormal TB on both sample types. An II ≤0.8 reliably excluded abnormal (>1.2 mg/dL) TB concentrations (serum, prevalence 25.4%: sensitivity 99.6%, NPV 99.7%; plasma, prevalence 16.7%: sensitivity 98.6%, NPV 99.4%). In our laboratory the use of an II value ≤0.8 as front-line test should allow the accurate “zero-cost” detection of samples with normal TB concentrations avoiding TB measurement in ∼35% of serum and ∼40% of plasma samples
The zebrafish scale as model to study the bone mineralization process
No full textDanio rerio (zebrafish) shows high similarity with humans in terms of bone architecture, bone cells, matrix proteins and molecular signalling. The fish body is covered by elasmoid scales which are part of the dermal skeleton. Since few data have been published about the function of the fish scale cells, we investigated the mineralization pattern of the scale and the role of the episquamal osteoblasts in the neodeposition of the bone tissue. First, we described a specific mineralization pattern and distribution of the bone forming cells in different areas of the scale. We observed along the external circuli that, during the scale growth, the marginal cells migrate and organize in a cord-like structure just before the mineralization process takes place generating a new circulus. These cells exhibit alkaline phosphatase activity, a well known mammalian osteoblastic differentiation marker. The internal circuli are also characterized by new matrix deposition. Thus, zebrafish scale represents a useful model for analyzing the osteoblast behaviour during bone formation and mineralization and it could be useful in physiological studies and pharmacological tests
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
- …
