Biomedical subjects

M Nicoli

Publications and source records attributed to M Nicoli.

At least 19 recordsLinked to original sources

PubMed1997

Clinical performance of leukocyte differential on the new Roche Cobas Vega haematological analyzer.

The Roche Cobas Vega is a five-part differential haematological analyzer evolving from the former Cobas Helios, Argos and Micros. As the leukocyte differential of Cobas Vega displays several interesting features, we analyzed its clinical performance and compared it either to three other commercial haematological analyzers (Technicon-Bayer H*2, Coulter STKS and Abbott CD-3500) or to the manual reference method, as described in the National Committee for Clinical Laboratory Standards (NCCLS) H20-A protocol. Within- and between-batch coefficients of variations (CVs) of the white blood cell differential were satisfactory and close, or even better than the ones reported for the other instruments: 0.81% (neutrophils), 1.87% (lymphocytes), 6.76% (monocytes), 7.73% (eosinophils) and 22.55% (basophils). The identification of abnormalities in the white blood cell differential was obtained either on the basis of the instrument-specific ranges or on the generation of one or more flags by comparison with results of the manual reference method. The Vega demonstrated remarkable performance in terms of specificity (90.0%), sensitivity (91.6%) and both positive (97.7%) and negative (69.1%) predictive values; likewise, the global efficiency was the best (90.3%) among the analyzers we evaluated. The flags generated in the presence of morphological abnormalities of the samples displayed excellent sensitivity (from 88.9% to 100%), specificity (from 93.5% to 98.3%) and satisfactory positive (from 51.1% to 66.7%) and negative (from 98.3% to 100%) predictive values. We conclude that the analytical performance of the new Cobas Vega haematological analyzer can significantly improve the identification of various haematological abnormalities as an important contribution to the accuracy is provided by the new staining for granulocytes.

Evaluation Studies as Topic↗

PubMed1995

Effect of pyridoxal 5'-phosphate on human neutrophil aggregation in vitro.

Pyridoxal 5'-phosphate inhibited polymorphonuclear leukocyte aggregation in vitro in a dose-dependent fashion at concentrations ranging from 0.5 to 0.001 mmol/l. At pyridoxal 5'-phosphate concentrations between 0.4 and 0.5 mmol/l mean inhibition of aggregation was about 50%-60%. In this range, and at lower pyridoxal 5'-phosphate concentrations, phorbol myristate acetate-activated polymorphonuclear leukocytes showed a normal increase in volume, whereas swelling was inhibited at higher concentrations of pyridoxal 5'-phosphate. Since pyridoxal 5'-phosphate can be administered as a vitamin to man without any relevant side-effects its role as a physiological anti-aggregant of polymorphonuclear leukocytes warrants further investigation.

Adult↗

PubMed1994

A simple assessment of human neutrophil adhesiveness.

The adhesiveness of human polymorphonuclear leukocytes was assessed in serum-coated polystyrene spectrophotometric cuvettes. Capped cuvettes, containing no more than 2 x 10(6) resting or concanavalin A-treated (100 micrograms/ml) polymorphonuclear leukocytes, were laid horizontally and subjected to three 90 degrees rotations on their major axis at fixed times. After incubation at room temperature, non-adherent cells remaining in suspension were counted on the Coulter counter STKS hematological analyzer. After a 16-min incubation (4 min each side of the cuvette) the adhesion of concanavalin A-activated neutrophils ranged from 98% to 100% and the adhesion of resting neutrophils from 30% to 35% (mean 32.4 +/- 2.2%, n = 10). An 8-min incubation (2 min each side) led to approximately 50% adhesion of concanavalin A-activated neutrophils (mean 49.9 +/- 2.2%, range 46%-54%, n = 16), whereas the adhesion of resting cells was about 21% (mean 21.4 +/- 1.6%, range 19%-24%, n = 16). The variation in percentage adhesion in repeated assays did not exceed 4% using concanavalin A-activated cells and 7.5% with resting neutrophils. The procedure is very rapid, easy to perform and precise, and no special apparatus or glassware is necessary. The method also allows microscopic evaluation of shape changes of adherent neutrophils through the clear sides of the cuvettes.

Animals↗

PubMed1994

Assessment of neutrophil aggregation by Coulter STKR and STKS haematological analysers.

We have studied an alternative method to aggregometry for the assessment of human polymorphonuclear (PMN) leucocyte aggregation. This simple, rapid and reliable procedure counts unaggregated cells on both Coulter STKS and STKR haematological analysers by the impedance principle. Aggregation of PMN was induced by 15 min incubation with fresh autologous serum (FAS) after a 10 min phorbol myristate acetate (PMA) activation of neutrophils in small aliquots (0.25 ml) of suspension containing about 4.0 x 10(9) PMN/1. Differences (x 100) between count of resting and PMA+FAS treated neutrophils/count of resting PMN reflect percent aggregation. By this procedure, PMN aggregation did not occur in autologous plasma from EDTA anticoagulated whole blood; it was partially inhibited by hydrocortisone, whereas inactivated or Zymosan activated sera gave values similar to those from FAS induced aggregation. PMA aggregation was dependent on Ca2+ + Mg2+ concentration. Intra-assay analytical variability did not exceed 4% on either instrument. Reference values (n = 20) of percent PMN aggregation were 50.7 +/- 4.7 on STKS and 47.1 +/- 4.8 on STKR. Most probably, the interindividual variance was due to the physiological variability of Mg2+ and/or Ca2+ concentrations in FAS. Thus, this procedure reflects the true PMN aggregability status in a given subject, and in a given electrolyte environment.

Adult↗

PubMed1994

High light scatter by neutrophils in the Bayer-Technicon H*2 analyzer: a screening test of morphologically defective responsiveness to in vitro chemotactic stimulation.

The Bayer-Technicon H*2 haematological analyser provides differential white blood cell count, including the assay of polymorphonuclear leukocytes by light scattering and the absorbance increase following the cytochemical reaction for myeloperoxidase. The mean value of polymorphonuclear leukocytes scatter, which reflects polymorphonuclear leukocytes volume, is printed in a separate report "for laboratory use only" as a ybar value in arbitrary units. In certain patients neutrophils displayed an unreported correlation between polymorphonuclear leukocytes high ybar basal values (> or = 37.00 arbitrary units) (determined on the H*2) and a defective response in vitro to the chemoattractant, formyl-methionyl-leucyl-phenylalanine (determined by microscopic evaluation of polymorphonuclear leukocytes shape change (polarization)). The patients showing no polymorphonuclear leukocyte response or a defective one to formyl-methionyl-leucyl-phenylalanine were all affected by "Systemic Inflammatory Response Syndrome (SIRS)". Therefore the predictive value of the positive test for SIRS is 100%. On the other hand 8.8% of SIRS patients had polymorphonuclear leukocytes < 37.00 arbitrary units of ybar basal value and a "normal" response to formyl-methionyl-leucyl-phenylalanine; the predictive value of the negative test being 90%. Since we demonstrated in vitro a dose-dependent deactivation of endotoxin or lipopolysaccharide-pretreated polymorphonuclear leukocytes, the "normal" response to formyl-methionyl-leucyl-phenylalanine of the "false negative" cases may occur because the endotoxaemia in these patients is too low to prevent it.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Size↗

PubMed1993

Lipoprotein(a) concentrations are increased in patients with myocardial infarction and angiographically normal coronary arteries.

It is generally accepted that Lp(a) is an independent risk factor of cardiovascular diseases. Since the apolipoprotein component of Lp(a) shows some homologies to plasminogen, it is, however, unclear as to whether the pathological effect is due to the role played by the lipoprotein in lipid metabolism or in the fibrinolytic system. We compared two groups of patients with myocardial infarction, with and without angiographically documented coronary artery disease. In the latter group, imbalances in the clotting system are very likely, while members of the former group may also display disturbances of lipid metabolism. The results show that the two groups display differences in lipid metabolism, whereas they have similar patterns of thrombogenicity indices and Lp(a) values. This study seems to support the hypothesis that Lp(a) does play a role in the fibrinolytic system, since even those myocardial infarctions without obstructive coronary artery disease have a high frequency of Lp(a) concentrations above 300 mg/l, i.e. similar to the situation found in the myocardial infarctions with angiographically documented coronary artery disease. Whether the high Lp(a) concentrations in the two groups are related to an impaired fibrinolysis will be the subject of further investigation.

Apolipoprotein A-I↗

PubMed1992

Volume, conductivity, and scatter changes of activated polymorphonuclear leukocytes: an estimation by Coulter Counter STKS analyzer.

Suspensions of phorbol myristate acetate-activated polymorphonuclear leukocytes were analyzed with a Coulter Counter STKS hematological analyzer. Phorbol myristate acetate activation induced an increase in polymorphonuclear leukocyte volume and conductivity, while scatter was unchanged. Phorbol myristate acetate-activated neutrophils in a suspension containing nitroblue tetrazolium showed increased scatter. The rise in scatter was phorbol myristate acetate dose dependent, completely inhibited by diphenylene iodonium and partially by dimethyl sulfoxide, two inhibitors of NADPH oxidase. Zymosan-activated polymorphonuclear leukocytes were notably larger with a characteristic position on discriminant function 1 display (volume versus scatter) of the analyzer. Volume and conductivity changes were seemingly inexplicable features of phorbol myristate acetate activation. The rise in scatter was produced by cytoplasmic precipitation of reduced nitroblue tetrazolium and thus by O2-generation in phorbol myristate acetate-activated neutrophils. Zymosan phagocytosis was responsible for the notable rise in polymorphonuclear leukocyte volume. The analysis of activated polymorphonuclear leukocytes by Coulter Counter STKS may provide useful information on their activation and a pragmatic approach for studying function.

Biphenyl Compounds↗

PubMed1990

Advantages of a new anticoagulant in routine hematology on the Coulter Counter S-Plus STKR analyzer.

The authors report the advantages of a new anticoagulant-antiaggregant mixture that avoids the deleterious effects of ethylenediaminotetraacetic acid (EDTA) on mean platelet volume and also prevents EDTA-induced platelet clumping. It is suitable for routine cell counting and sizing with the Coulter Counter S-Plus STKR. The values of the common hematologic parameters agree well with those from EDTA-treated samples and are stable for at least eight hours after sampling.

Anticoagulants↗

PubMed1990

Effects of ketanserin administration on lipid metabolism and platelet aggregation in hypertensive patients.

Lowering blood pressure is not totally effective in preventing the atherosclerotic complications of systemic hypertension. In hypertensive patients both platelet hyperaggregation and dyslipidemia have been suggested as important risk factors. The effect of 8 weeks' treatment with ketanserin on blood pressure, serum lipid parameters (cholesterol, triglycerides, LDL, HDL-C, apolipoprotein A1 and B) and platelet aggregation, induced by collagen, ADP, arachidonic acid, was evaluated in 10 patients with essential hypertension. Ketanserin was effective in lowering blood pressure in all patients, 6 of whom became normotensive. Both CHOL and TG levels and APO B were significantly reduced, whereas HDL-C and APO A1 were significantly increased after treatment. These results might be attributed to the antagonistic activity of ketanserin on alpha-1 adrenoceptors with a consequent inhibition of phosphodiesterase. Platelet aggregation, after stimulation with collagen and arachidonic acid, was significantly reduced secondary to the inhibition of intraplatelet serotonin synthesis and release. These results suggest that keranserin is effective in reducing blood pressure and in achieving normal serum lipid pattern and platelet aggregation. Therefore, this drug might be helpful in controlling the main risk factors for cardiovascular damage.

Adult↗

PubMed1987

Unpredictable effects of K3 EDTA on mean platelet volume.

The changes of mean platelet volumes (MPVs) begin immediately upon exposure of the blood to K3EDTA, and differences from sample to sample are unpredictable, predominantly in the first two hours from the venipuncture. MPVs variations can range from -25 to 23.1% in respect to MPVs in untreated whole blood immediately processed. These results were obtained by a new electrooptical device (Technicon H X 1) that provides complete blood cell counting and sizing. If whole blood is collected and diluted with a reagent used by the instrument to sphere and fix red blood cells and platelets, MPVs values do not change significantly within 180 minutes from venipuncture. This approach allows one to study the true values of MPVs on Technicon H X 1.

Blood Cell Count↗

PubMed1987