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Biomedical subjects

F Marangoni

Publications and source records attributed to F Marangoni.

At least 37 records · Page 2Linked to original sources
PubMed1997

Relationship of the time of storage and transfusion reactions to platelet concentrates from buffy coats.

BACKGROUND: Transfusion reactions to platelet concentrates prepared from buffy coats (BC-PCs) were reviewed to determine the effect of some variables of BC-PC preparation and storage: time of BC storage before BC-PC preparation (1-2 days); time of BC-PC storage before transfusion (1-5 days); no white cell reduction versus laboratory and bedside BC-PC white cell reduction. STUDY DESIGN AND METHODS: A multiple linear logistic regression model was used by which the relative effect of one variable is expressed as the relative risk of transfusion reaction against a baseline level (1-day storage, no white cell reduction). RESULTS: During the 14 months of study, a total of 2707 BC-PC transfusions were given to 192 patients; 37 reactions (1.4%) were reported in 25 patients (13%). The transfusion reactions were febrile, nonhemolytic in 23 cases; allergic in 5; febrile and allergic in 2; and other in 7. The relative risk of transfusion reaction to BC-PCs prepared from BCs stored for 2 days was 1.98 times that to BC-PCs prepared from BCs stored for 1 day (p = 0.07). The relative risk of transfusion reaction of 5-day-old BC-PCs was 10.7 times that of 1-day-old BC-PCs (p = 0.001). The relative risk of transfusion reactions of BC-PCs white cell-reduced in the laboratory and at the bedside were 0.65 (p = 0.3) and 1.87 (p = 0.1) times, respectively, that of non-white cell-reduced BC-PCs. CONCLUSION: Time of storage seems to be an important variable associated with BC-PC transfusion reaction.

Blood Component Transfusion↗
PubMed1995

The effects of n-3 and n-6 polyunsaturated fatty acids on plasma lipids and fatty acids of treated phenylketonuric children.

Dietary-treated phenylketonuric patients (PKUs) display low levels of long-chain polyunsaturated fatty acids (PUFA) in plasma lipids. In a 6-month clinical trial we observed a decrease of triglycerides and an increase of n-3 long-chain PUFA in plasma of PKUs supplemented with fish oil, while no major differences in respect to the baseline values were found in a group supplemented with blackcurrant oil. A more complete source of long-chain PUFA of both the n-6 and n-3 series should be investigated for dietary supplementation of PKU patients.

Child↗
PubMed1995

myc-immortalized microglial cells express a functional platelet-activating factor receptor.

The autacoid platelet-activating factor (PAF) takes part in a complex network of interactions regarding the cellular components of nervous tissues. Efforts aimed at characterizing the effects of PAF in the brain have been recently focalized on neurons because PAF exerts pleiotropic effects on these cells. Less attention has instead been paid to the glial component of the brain. We have used microglial cell lines immortalized from 13-day-old mouse embryo brains by a myc-transducing retrovirus. When exposed to physiological doses of PAF, immortalized microglial cells showed increases in intracellular free calcium concentrations due to release of calcium from internal stores, as well as to extracellular calcium influxes. These profiles of reactivity were independent from the immortalizing process, being observable in primary microglial cultures and in immortalized clones showing different proliferative rates. PAF was also able to induce transient expression of the c-fos protooncogene in serum-starved cultures and induced a strong chemotactic response in microglial cells. In contrast with control macrophage cultures, PAF did not promote prostaglandin or leukotriene synthesis in immortalized cells. This was most likely due to the low amount of total arachidonic acid found in immortal microglia, with respect to that observed in freshly isolated cells. Our data suggest that several of the effects observed after PAF stimulation might be independent from PAF-induced arachidonic acid metabolism. The availability of an in vitro microglial model might now help in studying the proinflammatory effects of PAF, both direct or microglia mediated, in the neural environment.

Animals↗
PubMed1995

Prolonged inhibition of platelet aggregation after n-3 fatty acid ethyl ester ingestion by healthy volunteers.

This study addressed two questions: 1) whether a relatively low dose of n-3 fatty acid ethyl esters (n-3 FAs) administered to healthy volunteers for a prolonged period of time would exert beneficial effects on plasma lipids, platelet function, and thromboxane biosynthesis; and 2) whether a short-term loading treatment (6 wk) with 6 g n-3 FAs/d followed by 12 wk with 3 g/d results in more pronounced effects. After 6 wk treatment a reduction of plasma triglyceride concentration and an accumulation of EPA and DHA in plasma were observed. A longer period of treatment with n-3 FAs was necessary to affect platelet aggregation and thromboxane A2 biosynthesis. At 12 and 18 wk, platelet aggregation, thromboxane A2 formation, and the excretion of thromboxane metabolites in urine were reduced, particularly in subjects who received 6 g n-3 FAs/d during the initial 6 wk. After treatment ended, triglyceride and thromboxane A2 biosynthesis returned to baseline values within 4 wk, whereas platelet aggregation remained impaired for > or = 14 wk. The longlasting impairment in platelet aggregation was accompanied by the retention of n-3 FAs in platelet phospholipids.

Administration, Oral↗
PubMed1994

Photochemical conjugation of mammalian cells to polymeric supports and membranes: a kinetic study.

A commercial polyester acrylate prepolymer, to which a 2:3 wt/wt ratio of tripropyleneglycol diacrylate was added to increase photopolymerization rate, was employed as photochemical conjugating agent, through photografting. 1,2-Diphenyl,2,2-dimethoxyethanone was added as standard photoinitiator (7.0 wt/wt%), together with varying amounts (0.003-4.0 wt/wt%) of some proprietary photocatalytic systems, based on the following photocatalysts: mu-peroxo-bis[N,N'-ethylene-bis(salicylideneiminato)cobalt(I II) (I), vanadium(V) triethoxide (II), and a synergic mixture of vanadium(V) tri-t-butoxide and tri-i-propoxide (III). A homogeneous suspension containing (10 +/- 2) x 10(5) human thyroid follicular cells per milliliter of photochemically reacting medium was photografted, at a surface density of 6.5 +/- 0.7 mg.cm-2 of diacrylate prepolymer mixture, onto polystyrene plates or onto commercial microfiltration and ultrafiltration membranes consisting of nonwoven cellulose tissues with known porosities varying between 5 and 30 microns and in photografted polyester acrylate-based membranes with a cutoff of 50 +/- 5 KD. Bioconjugation yields, as a function of photografting time, were measured gravimetrically and by multiple internal reflection IR spectroscopy. Three series of experiments were performed: 1) measurements of graft yields of the prepolymer, and of the parallel disappearance of double bonds, in the absence of mammalian cells; 2) the same as 1), in the presence of thyroid follicular cells; 3) the same as 2), but with the photoinitiating system formed by the standard photoinitiator alone, with no photocatalyst. Results show that if a suitable photocatalyst is not added, no practical conjugation is possible. An appropriate choice of the photocatalytic system and of its concentration allows reduction of irradiation times (e.g., by a factor of about 2 x 10(4) calculated as the mean lifetime ratio, between the uncatalyzed system and that with 0.1 wt% of [III]), thus minimizing cell inactivation and/or improving responsiveness to the bioassay. From this point of view, photoactivity of (III) is outstanding. The very small, but clearly perceptible, influence of polymeric support on bioconjugation is also commented upon.

Animals↗
PubMed1994

Quality control of red cell filtration at the patient's bedside.

BACKGROUND: Concern has been raised about the quality of white cell (WBC) reduction in blood components when it is performed by filtration at the patient's bedside. Thus, the quality of red cell (RBC) filtration performed at the bedside through two new flatbed WBC-reduction filters was evaluated. STUDY DESIGN AND METHODS: In the laboratory, 25 and 10 RBC units suspended in additive solution were stored for 1 to 2 and 14 to 21 days, respectively, and filtered through each filter. At the end of filtration, an automated complete blood count and a manual WBC count (Nageotte chamber) were determined in two samples collected from 1) a segment clamped at 5 and 25 cm below the filter along the line connecting prefiltration and postfiltration bags and 2) the postfiltration bag. In addition, 10 of the 11 nurses of the hematology outpatient clinic administered to hematologic patients 25 RBC units stored for 1 to 2 days through each type of filter. At the end of transfusion, a segment was collected from the transfusion set and a WBC count was performed as described above. No filter priming or rinsing with saline was done. RESULTS: WBC counts obtained after laboratory filtration in the segments were similar to those obtained from the postfiltration bags and from the segments collected at the bedside in all cases, with the exception of 14- to 21-day-old RBCs filtered in the laboratory through one of the filters, which produced slightly higher WBC counts in the segments than were seen in the postfiltration bags. The difference was not significant. In no case was the count in the postfiltration bag higher than that in the segment. Nurse training was easy, and bedside filtration was associated with no untoward effects. CONCLUSION: The RBC filtration at the patient's bedside can be equal in quality to that performed in the laboratory, at least in such clinical settings as hematology and oncology departments in which blood transfusion is common practice, and if simple training is provided to the nursing staff. Under the conditions of this study, it seems that quality control of RBC bedside filtration is feasible and simple.

Blood Transfusion↗
PubMed1994

Frozen platelet plates for platelet antibody detection and cross-match.

We performed 2 studies aimed at developing a frozen platelet panel suitable for platelet cross-matching. The stability of the most important platelet membrane glycoproteins and the reactivity of antigens of the human platelet antigen (HPA) and of the human leukocyte antigen (HLA) systems were evaluated with the platelet suspension immunofluorescence test (PSIFT) in a panel of platelets frozen in microplates with 6% dimethylsulfoxide. In study No. 1 we evaluated platelet reaction with a broad-spectrum weak anti-HLA and a potent anti-HPA-1a antiserum and the expression of glycoproteins Ib and IIb/IIIa complex on platelet membrane before freezing and after 0.5, 1, 2, 3, 4, 5, 6 and 12 months of storage at -80 degrees C. In study No. 2 we examined platelet reactivity with anti-HPA-1b, -HPA-2a, -HPA-3a, -HLA-A2, -HLA-A3 of platelets stored frozen for 12 months in parallel with fresh platelets from the same donors. Study No. 1 showed that glycoprotein expression was stable and that the weak anti-HLA and the potent anti-HPA-1a antibodies were clearly detected during 12 months at -80 degrees C. Of the 35 paired PSIFT performed in study No. 2 with fresh and frozen/thawed platelets incubated with anti-HPA-1b, -HPA-2a, -HPA-3a, -HLA-A2, -HLA-A3 antisera and AB serum, concordant reactions were obtained in all cases with the exception of 1 case of HLA-A3-positive platelets incubated with anti-HLA-A3 antiserum, that was reactive with frozen/thawed platelets but nonreactive with fresh platelets from the same donor.(ABSTRACT TRUNCATED AT 250 WORDS)

Antigens, Human Platelet↗
PubMed1994

n-3 fatty acid ethyl ester administration to healthy subjects and to hypertriglyceridemic patients reduces tissue factor activity in adherent monocytes.

n-3 Fatty acids are known to influence several functions of monocytes, including adhesion, cytokine synthesis, and superoxide generation. Monocytes express tissue factor, a membrane-bound glycoprotein, that acts as a catalyst in the coagulation cascade. In this study we evaluated the effects of administration of n-3 fatty acid ethyl esters to healthy volunteers and to hypertriglyceridemic patients on tissue factor activity (TF activity) in adherent monocytes. n-3 Fatty acids containing 75% eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) (ratio of EPA to DHA, 1.34) were administered (3 g/d) to normal volunteers for 18 weeks. In addition, the effects of this treatment were evaluated in 30 hypertriglyceridemic patients for 24 weeks by using a double-blind, placebo-controlled study. TF activity in adherent monocytes was evaluated with a one-stage clotting assay. Plasma and monocyte fatty acid compositions were determined by gas-liquid chromatography. In healthy volunteers, n-3 fatty acids significantly reduced TF activity in adherent monocytes either in the unstimulated condition or after exposure to endotoxin. The inhibitory effect was observed after 12 weeks of treatment and was more pronounced after 18 weeks (> 70%, P < .001 versus baseline). Concomitantly, levels of EPA and DHA increased in plasma and monocyte lipids. Interestingly, after stopping treatment, monocyte TF activity remained inhibited for at least 14 weeks. Treatment with n-3 fatty acids for 24 weeks also resulted in a significant reduction of TF activity in adherent monocytes from hypertriglyceridemic patients (-31% and -40% in unstimulated and endotoxin-stimulated cells; P < .05 versus baseline).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

Changes of n-3 and n-6 fatty acids in plasma and circulating cells of normal subjects, after prolonged administration of 20:5 (EPA) and 22:6 (DHA) ethyl esters and prolonged washout.

Eight normal volunteers (four men and four women) were treated with 3 x 1 g capsules of n-3 fatty acid ethyl esters for a period of 18 weeks, followed by a 24 week washout. Fatty acids of plasma, platelets, monocytes and red blood cells were analyzed at 0, 6, 12 and 18 weeks of treatment and at 4, 14 and 24 weeks of washout. During treatment, accumulation of EPA in plasma and cells was almost maximal at 6 weeks, whereas that of DHA reached a peak at 18 weeks. Arachidonic acid declined somewhat at 12 weeks in plasma and more markedly at 18 weeks in red blood cells and monocytes. During washout, EPA returned rapidly toward pretreatment values in all compartments, but it remained significantly higher in plasma and platelets at the end of washout. DHA declined more slowly, maintaining higher than basal values in plasma and platelets and lower than basal in red blood cells, at the end of washout. Rebound increments of AA occurred in plasma. Finally, the plasma levels of AA, but not those of the n-3 fatty acids, were more markedly modified in males than in females. The presented results suggest interactions between circulating fatty acids in the different compartment after n-3 FA administration, and indicate that very long washouts are necessary for a complete recovery from the induced fatty acid modifications.

Adult↗
PubMed1993

n-6 and n-3 fatty acid accumulation in thp-1 cell phospholipids.

The human monocytic leukemia cell line THP-1 is depleted of the long-chain n-6, AA, when compared to human monocytes. This reflects the low availability of this FA in the growth medium generally used for cultured cells. The effects of AA, as well as EPA, supplementation of THP-1 cells on the incorporation of these FA in cell PL, especially in PC and PE, was investigated. In addition the incorporation of labeled AA in PL from THP-1 cells was compared to that in human monocytes. Measurements were done through HPLC separation of PL, detected by UV absorption and radioactivity, FA analysis by GC and characterization of PC subclasses by FAB-MS. Marked differences were observed in the incorporation of the two FA in cell PL, particularly two PC subclasses, and in the accumulation in individual PL after supplementation of THP-1 cells. Accumulation of AA and EPA in THP-1 cells appeared to be mutually independent. The incorporation of AA was also quite different in THP-1 from that in monocytes. Thus, characterization of the FA content in lipids of cultured cells is an essential requirement for optimal utilization of these cells.

Cell Division↗
PubMed1993

Modulation of lipid derived mediators by polyunsaturated fatty acids.

Cell stimulation by a number of agonists triggers the formation of products of lipid hydrolysis, which act either as intracellular mediators of signal transduction or as modulators of cell-cell interactions. This process is mediated by the activation of hydrolytic enzymes, the phospholipases (PLase), especially the A2 and C, acting on cell phospholipids (PL). Among the major products being formed, the following: a) the inositol phosphates (IP), especially IP3, and diacylglycerols (DAG) generated intracellularly from phosphoinositides through PLase C, b) the eicosanoids, the arachidonic acid (AA) metabolites produced through combined PLase A2 and (cyclo- and lip-) oxygenase activities, and released from cells, c) the ether lipid PAF, derived from alkylacyl phosphatidylcholine through PLase A2, have attracted the attention of investigators for their important biological roles. Interest has also been recently developed towards products of sphingolipid hydrolysis, sphingosine and ceramide, which are generated by various cell types after stimulation, and exert biological activities. Cell glycerophospholipids are rich in long-chain polyunsaturated fatty acids (PUFA) of the n-6, namely AA 20:4 n-6, and n-3, mainly docosahexaenoic acid (DHA) 22:6, series. These compounds are differentially distributed among the various PL classes and their levels in cells are modulated through the intake with the diet of either the 18-C fatty acids (FA), precursors, linoleic 18:2 n-6, and, alpha-linolenic 18:3 n-3, respectively--followed by conversion to their long-chain PUFA derivatives, or through the intake of the performed compounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Communication↗
PubMed1993

Platelet concentrates from buffy coats: improved conditions for preparation and evaluation in routine clinical use.

Since 1990, platelet concentrates prepared by soft centrifugation of buffy-coat pools diluted with a glucose-free, commercially available crystalloid solution (BC-PC) are the first choice product for all platelet recipients in our institution. Numerous in vitro and in vivo observations from our own and other laboratories indicate that BC-PC compare favorably to PC prepared from platelet-rich plasma (PRP). In the present in vitro study we evaluated traditional and bottom-and-top bags and modified centrifugation conditions with the aim of increasing in vitro platelet yield in BC-PC. This was 14-18% higher compared with our previous protocol when prolonged centrifugation and bottom-and-top bags were used. In addition, we evaluated post-transfusion platelet count increments in 42 unselected adult hematological patients routinely transfused with 703 1-5 day-old BC-PC pools. Transfusion data were managed with PLATELET, an MS-DOS compatible program which includes automated calculation of transfusion efficacy and periodic patient reports. Mean pre-, 1 h and 24 h post-transfusion platelet counts were 16, 38 and 28x10 9/L, respectively. Mean 1 h and 24 h post-transfusion platelet count increments, expressed as percentage of expected, were 40 and 24%, respectively. These data were similar to those obtained previously in 189 unselected hematological patients given 2432 PRP-PC transfusions (mean 1 h post-transfusion increment 46% of expected). The present in vitro study confirms that similar platelet yields can be obtained with the BC and PRP methods. In vivo findings show that also in routine conditions post-transfusion increments of PRP-PC and BC-PC are similar.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

White cell-reduced red cells prepared by filtration: a critical evaluation of current filters and methods for counting residual white cells.

White cell (WBC) reduction, red cell (RBC) recovery, and filtration time were determined in 1-day-old standard and buffy coat-depleted RBCs filtered in the laboratory through six commercial filters for WBC reduction. Residual WBCs were counted with a Bürker chamber (BC), with a Nageotte chamber (NC), and by flow cytometry (FC). Results show that BC counts were 0 in several cases in which WBCs were detected with NC and FC, which indicated that the traditional BC method is too insensitive in use with currently available filters. Calibration curves performed by FC and with NC with samples containing known concentrations of WBCs from 1000 to 1 per microL showed that both FC and NC detected, on average, 67 percent of WBCs present in the samples (efficiency). However, the efficiency of FC showed small variability (61-70%) at different WBC levels, whereas the variability with NC was large (39-91%). This greater variability prevented the correction of NC counts by using a single factor and indicated difficulty in NC standardization. Therefore, because our main aim was to compare different filters rather than to define absolute levels of WBC contamination, uncorrected FC and NC counts were chosen to be reported. True WBC counts per unit should not exceed values that can be obtained by dividing uncorrected counts by the lowest efficiencies (61% for FC and 39% for NC). Uncorrected NC and FC counts were below 2 x 10(6) per unit in all units processed through three of the filters and below 5 x 10(6) per unit in all units processed through the other three.(ABSTRACT TRUNCATED AT 250 WORDS)

Erythrocytes↗
PubMed1993

Single-donor platelet concentrates stored in synthetic medium. In vitro and in vivo studies.

Single-donor platelet concentrates (PC) were prepared in 80-120 ml plasma and stored in two polyolefin bags after addition of 250 ml plasmalyte, a simple, glucose-free synthetic medium that was previously used for platelet storage; when compared to PC stored in plasma, PC stored in plasmalyte, showed similar platelet quality, morphology and function after 5 days of storage. In vivo increments observed after transfusion of PC stored for 5 days in plasmalyte were similar to those observed after transfusion of 1-2 day old PC stored in plasma. Moreover, transfusion of 5-day old PC stored in plasmalyte was associated with correction of prolonged bleeding times in all 3 of the 3 patients evaluated. It is concluded that plasmalyte seems to be promising as a medium for single-donor PC storage.

Blood Donors↗