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U Lippi

Publications and source records attributed to U Lippi.

65 records · Page 4Linked to original sources
PubMedDate not supplied

A new chemical procedure for selective sequential separation of serum lipoproteins.

A new chemical procedure for selective sequential separation of serum lipoproteins is described. Low density lipoproteins (LDL) were precipitated by polyvinylsulfate and the precipitates were redissolved in NaCl 0.45 mol/l. Very low density lipoproteins (VLDL) were precipitated from LDL-free supernatants by PEG-6000 at 100 g/l final concentration, pH 10, and the precipitates were redissolved in NaCl 0.15 mol/l. For the precipitation of high density lipoproteins (HDL), apolipoprotein B-free supernatants were treated by PEG-6000 at 266 g/l final concentration and the precipitates were redissolved in NaCl 0.15 mol/l. The procedure was effective up to a serum triglyceride concentration of 4.0 mmol/l as well as in serum samples without chylomicrons or remnants. The determination of cholesterol and triglyceride contents in separated lipoproteins allows the study of their chemical composition in normo- and moderately hypertriglyceridemic serum samples.

Chemical Precipitation↗
PubMedDate not supplied

Effects of posture on plasma and serum viscosity.

This study demonstrates the importance of defining normal reference population ranges for P- and S-viscosity with respect to posture. The normal ranges determined for P-viscosity are not acceptable as a reference range for a hospitalized population that is predominantly in a supine position. Mean percentage changes of P- and S-viscosity in the recumbent posture as compared to the same population in the upright posture were 7.51 and 5.88, respectively.

Adult↗
PubMedDate not supplied

Volumetric changes in phorbol myristate acetate activated neutrophils: a rapid and simple assay using Coulter counter STKR and STKS hematological analyzers.

BACKGROUND: The aim of this study was to investigate some physical changes (volume, conductivity and scatter) in human polymorphonuclear leukocytes (PMN) activated with phorbol myristate acetate (PMA). METHODS: Volume changes in PMA-activated neutrophils were assayed by both STKR and STKS, two Coulter hematological analyzers. Scatter changes in PMN activated by PMA in suspensions containing nitro-blue tetrazolium (NBT) were investigated on STKS scattergrams. RESULTS: PMA activation induced PMN volumetric increases that could be assayed with STKR and displayed with STKS. The activation of PMN in suspension containing NBT induced cellular scatter changes on STKS scattergrams. The differences in scatter between resting and PMA-activated neutrophils may thus provide a semiquantitative assay of NBT reduction and superoxide production. Volume changes in PMA-activated neutrophils were due to cellular swelling through water uptake, induced by Na+/H+ antiport activation and Na+ influx. Since volume changes in PMA-activated neutrophils might occur without O2- production and vice versa, in the cases in which PMA activation of protein kinase C cannot be demonstrated by O2- production, the effect of PMA on protein kinase C- mediated Na+/H+ antiport activation, and in turn on PMA volume changes, reflects protein kinase C activation. CONCLUSIONS: A screening of neutrophils unresponsive to volumetric changes from PMA activation may be easily performed using both Coulter STKR and STKS analyzers, whereas expected or defective PMA-induced production of O2- may be semi-quantitatively evaluated by STKS.

Adult↗
PubMedDate not supplied

EDTA-induced platelet aggregation can be avoided by a new anticoagulant also suitable for automated complete blood count.

In vitro EDTA-induced platelet aggregation is a fairly rare event but can have serious clinical consequences producing pseudothrombocytopenia and pseudoleukocytosis. Sixteen specimens with previously recognized EDTA-induced platelet aggregation were collected in a new anticoagulant-antiaggregant mixture containing trisodium citrate 17 mmol/l, pyridoxal 5'-phosphate 11.3 mmol/l and Tris 24.76 mmol/l (CPT mixture) and analyzed at various times after venepuncture with four hematological instruments: Coulter Counter S-Plus STKR, Technicon H6000, Technicon H1 and Ortho ELT-8. In CPT-anticoagulated specimens the signals and instrumental flags of platelet clumping were absent, and the platelet number correlated very well with a microscopic count from a finger stick drawn into Unopette. The complete blood count was very similar in "normal" hematological specimens either collected in K3. EDTA or in CPT, although Technicon H1 and Ortho3 ELT-8 required a suitable calibration for MCV and hematocrit in the latter mixture. Mean platelet volume was stable for up to 24 h only in CPT-collected specimens, if it was measured on a Coulter Counter S-Plus STKR. In routine hematological practice CPT can be an alternative anticoagulant to K3. EDTA, most suitable for automated complete blood count and useful in avoiding EDTA-induced platelet clumping.

Anticoagulants↗
PubMedDate not supplied

Alpha-naphthyl butyrate esterase (a selective cytochemical monocyte marker).

This paper describes a cytochemical technique for alpha-naphthyl butyrate esterase demonstration in monocytes obtained from peripheral blood of normal subjects, of a patient with reactive monocytosis and of a patient with myelomonocytic leukemia. It utilizes pH 6.1 alpha-naphthyl butyrate as substrate. At this pH value, alpha-naphthyl butyrate is a specific monocyte marker. The cytochemical procedure proposed is simple, rapid and standardized, as it utilizes stable and easily available reagents.

Carboxylic Ester Hydrolases↗