Biomedical subjects

M Montagnana

Publications and source records attributed to M Montagnana.

3 recordsLinked to original sources

PubMed2006

Evaluation of platelet turnover by flow cytometry.

The number of circulating newly produced platelets depends on the thrombopoietic capacity of bone marrow as well as platelet removal from the bloodstream. Flow cytometric analysis with thiazole orange (TO), a fluorescent dye that crosses platelet membranes and binds intracellular RNA, has been used to measure circulating reticulated platelets (RPs) with high RNA content as an index of platelet turnover. We first assessed the specificity of TO flow cytometry and then applied this method in the diagnosis of thrombocytopenia caused by impaired platelet production or increased destruction. We also explored the utility of TO flow cytometry to predict thrombocytopoiesis after chemotherapy-induced bone marrow aplasia. Venous blood, anticoagulated with K(2)EDTA, was incubated with 0.6 microg/ml TO plus an anti-GPIIIa monoclonal antibody. The mean percentage of RPs in control subjects (n = 23) was 6.13 +/- 3.09%. RPs were 10.41 +/- 9.02% in patients (n = 10) with hematological malignancies during aplasia induced by chemotherapy and a significant increase in RPs (35.45 +/- 6.11%) was seen in the recovery phase. In 10 patients with idiopathic thrombocytopenic purpura, the percentage of TO positive platelets was 67.81 +/- 18.79 (P < 0.001 vs. controls). In patients with thrombocytopenia associated with hepatic cirrhosis (n = 21; 21.04 +/- 16.21%, P < 0.001 vs. controls) or systemic lupus erythematosus (n = 6, 29.08 +/- 15.57%; P < 0.001 vs. controls) increases in TO-stained platelets were also observed. Measurement of TO positive platelets may be a reliable tool for the laboratory identification of platelet disorders, with a higher sensitivity than measurement of platelet volume. Measurement of RPs may also prove useful to recognize the underlying pathogenetic mechanisms in thrombocytopenia.

Adolescent↗

PubMed2006

Venous stasis and routine hematologic testing.

Prolonged venous stasis, as generated by a long tourniquet placement, produces spurious variations in several measurable analytes. To verify to what extent venous stasis influences routine hematologic testing, we assessed routine hematologic parameters, including hemoglobin, hematocrit, red blood cell count (RBC), main cell hemoglobin (MHC), main cell volume (MCV), platelet count (PLT), main platelet volume (MPV), white blood cell count (WBC) and WBC differential on the Advia 120 automated hematology analyzer in 30 healthy volunteers, either without venous stasis (no stasis) or after application of a 60 mmHg standardized external pressure by a sphygmomanometer, for 1 (1-min stasis) and 3 min (3-min stasis). Although the overall correlation between measures was globally acceptable, the mean values for paired samples were significantly different in all parameters tested, except MCV, MHC, PLT, MPV, eosinophils, basophils and large unstained cells after 1-min stasis and all parameters except MCV, MHC, MPV and basophils after 3-min venous stasis. As expected RBC, hemoglobin and hematocrit displayed a significant trend towards increase, whereas WBC and the WBC subpopulations were decreased. Difference between measurements by Bland and Altman plots exceeded the current analytical quality specifications for desirable bias for WBC, RBC, hemoglobin, hematocrit, lymphocytes and monocytes in samples collected after either 1- and 3-min stasis. These results provide clear evidence that venous stasis during venipuncture might produce spurious and clinically meaningful biases in the measurement of several hematologic parameters, prompting further considerations on the usefulness of adopting appropriate preventive measures for minimizing such influences.

Adult↗

PubMed2005

[Preoperative laboratory testing].

The preoperative laboratory screening is commonplace in clinical practice and is traditionally defined as the practice of prescribing laboratory testing before surgery on patients undergoing a given procedure. The wide heterogeneity of the solutions prospected over the past decades emphasizes the objective difficulty at issuing definitive guidelines and recommendations. Despite its widespread use, a systematic evaluation of the clinical and cost-effectiveness of routine laboratory testing demonstrates that several approaches are as yet unsuitable, as inappropriate investigations may lead to evaluation of borderline or false-positive laboratory abnormalities. Three major difficulties can be identified when issuing reliable recommendations: articulation and appropriateness of diagnostic protocols, contestualization, in terms of surgical procedures and suitable clinical contests that might achieve the greatest advantages from results of laboratory testing, and impact of these tests on clinical management and outcome. This article aims to provide a comprehensive review of the current literature on this topic, attempting to suggest a suitable approach to the puzzling issue of preoperative laboratory testing.

Clinical Laboratory Techniques↗