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Biomedical subjects

P Rebulla

Publications and source records attributed to P Rebulla.

At least 91 records · Page 5Linked to original sources
PubMed1993

Role of lactate in platelet storage lesion.

It is known that lactate accumulation may cause a pH fall in platelet concentrates (PC) during storage, and this phenomenon causes platelet morphological lesions and loss of platelet in vivo viability. In this study, we added increasing amounts of lactate to identical PC in order to evaluate the role of hydrogen ion accumulation in determining platelet activation and lesion during storage. Six hours after PC preparation, lactate was added to PC1 and PC2 at 20 and 12 mM final concentrations, respectively, while PC3 served as control. In PC1, pH was lower than 6.3, and platelet function and discoid morphology were lost. PC2 were stored for 7 days at pH values ranging from 6.4 to 6.6, and most results of in vitro measurements reflecting platelet function such as osmotic reversal, ATP release and aggregation in response to different stimuli were not significantly inferior when compared to controls. The addition of lactate had no apparent effect on the rise of platelet activation markers P-Selectin, lysosome-like protein gp 53, platelet-bound fibrinogen and granulophysin, while a reduction of borderline significance was observed in glycoprotein Ib expression after pH reduction to values lower than 6.6. It is concluded that the rise of platelet activation markers during storage reflects platelet lesions different from those determined by lactate per se.

Blood Platelets↗
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↗
PubMed1992

Platelet quality after 15-day storage of platelet concentrates prepared from buffy coats and stored in a glucose-free crystalloid medium.

It has been reported previously that platelet concentrates (PCs) prepared from buffy coat pools diluted in a simple, glucose-free medium (BC-PCs) are effective in thrombocytopenic patients after 4 to 12 days of storage. Such preparations produce platelet increments similar to those of traditional PCs prepared from platelet-rich plasma (PRP-PCs) stored for 1 to 3 days. The purpose of this study was to obtain a series of in vitro measurements during storage to allow a more detailed characterization of BC-PCs and a more detailed comparison of BC-PCs with PRP-PCs. At the beginning of storage, the level of (alpha granule membrane protein-140 (GMP-140), a marker of platelet activation, was significantly higher on PRP-PC platelets, and BC-PCs were superior in measurements reflecting platelet function, such as osmotic reversal, ATP release, and aggregation with collagen. Compared to PRP-PCs, BC-PCs were superior in the percentage of discs, total ATP, and glycoprotein lb expression by Day 7. This superiority became more striking on Day 11. Overall, 15-day-old BC-PCs compared favorably to 7-day old PRP-PCs: BC-PCs were superior in ATP release and aggregation with collagen, but they were not significantly different for all other measurements reflecting platelet quality and function. Thus, the quality of platelets in BC-PCs was superior on Day 1, and this superiority progressed as storage continued. In addition, the metabolism of BC-PCs was favorable.(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1992

Role of acetate during platelet storage in a synthetic medium.

It has previously been shown that buffy coat platelet concentrates (BC-PCs) stored in a medium made up of approximately 70 percent platelet storage medium (Plasma-Lyte A, PL) and 30 percent plasma (BC-PC-P) are effective in vivo after 9 to 12 days of storage. In addition to sodium, potassium, magnesium, and chloride, PL contains 27 mM (27 mmol/L) sodium acetate and 23 mM (23 mmol/L) sodium gluconate. This study investigated the effect of acetate and gluconate on platelet metabolism. Identical BC-PCs were stored at 22 +/- 2 degrees C in PL (BC-PC-P); PL with gluconate but without acetate, termed PL-A (BC-PC-A); or PL with acetate but without gluconate, termed PL-G (BC-PC-G). On Day 1 of storage, no significant differences were seen between the three groups of BC-PCs. In both BC-PC-P and BC-PC-G, pH and bicarbonate were stable at 7.0 +/- 0.03 and 8.4 +/- 0.9 mEq per L throughout 10 days of storage, whereas in BC-PC-A, they fell to 6.7 +/- 0.05 and 5.5 +/- 0.8 mEq per L on Day 5 (p less than 0.01 vs. Day 1) and to 6.1 +/- 0.1 and 1.2 +/- 0.4 mEq per L, respectively, on Day 10. The buffering capacities of 70 percent PL, PL-A, or PL-G and 30 percent plasma were similar in a platelet-free setting when incremental additions of lactic acid were made. The role of acetate was further studied by adding 14C- or 3H-labeled acetate to BC-PC-P.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetates↗
PubMed1992

HIV and HTLV infections in 1305 transfusion-dependent thalassemics in Italy. The COOLEYCARE Cooperative Group.

OBJECTIVE: To evaluate the prevalence of antibodies to HIV-1/2 and HTLV-I/II in 1305 transfusion-dependent beta-thalassemics treated in 36 centres in Italy. DESIGN: Patient serum samples were collected during 1990 and tested in Milan. METHODS: Sera were screened using an enzyme-linked immunosorbent assay (ELISA) containing viral lysate antigens from HIV-1 and HIV-2, and a particle agglutination assay for the detection of antibodies to HTLV-I and HTLV-II. Repeatedly reactive samples were examined by Western blot (WB) assays containing recombinant and viral lysate antigens. Differential diagnosis was finally made by ELISA based on synthetic peptides. RESULTS: Samples from 36 of the 1305 patients (2.76%) contained anti-HIV-1 antibodies. In four patients seroconversion occurred after the implementation of anti-HIV-1 screening in blood donors in Italy (1985). Of the 36 HIV-1-antibody-positive samples, four were HIV-2 [corrected] WB indeterminate. These four samples were negative in assays based on specific synthetic peptides, suggesting cross-reactivity. Anti-HTLV-I antibodies were found in two patients from Sicily and one from Apulia, both southern Italian regions. Anti-HTLV-II antibodies were detected in another patient from Sicily. CONCLUSIONS: Antibodies to HIV-1, HIV-2, HTLV-I and HTLV-II were detected in 2.76, 0, 0.23 and 0.08% of patients, respectively. The residual risk of HIV-1 infection through blood transfusion after the implementation of anti-HIV-1 screening in blood donors in Italy was approximately 1:50,000 blood units; this is based on an approximate number of 200,000 blood units administered to our group of patients during 1986-1990 and the occurrence of four new anti-HIV-1 seroconversions. Seroconversions to HTLV-I/II suggest that these viruses are present in Italian blood donors.

Adolescent↗
PubMed1992

Incidence of AIDS in HIV-1 infected thalassaemia patients. European and Mediterranean W.H.O. Working Group on Haemoglobinopathies and Cooleycare.

To estimate the cumulative incidence of acquired immunodeficiency syndrome (AIDS) in thalassaemia major patients (TMP) human immunodeficiency virus (HIV-1) infected through transfusion, 79 seropositive TMP were studied. At inclusion, mean age was 12.4 +/- 6.6 years; 40 were men; 21 were splenectomized. Centers for Disease Control, 1986 (CDC) stages and prescription of zidovudine were noted at least once a year. Cumulative incidence of AIDS and standard error were calculated using non parametric life table method. Age, sex, acute infection and splenectomy associations with progression to AIDS were tested using Breslow statistic. The median follow-up period was 4 years 11 months. At the end of the study period, 43 TMP were in CDC stage II, 23 in CDC stage III and 13 in CDC stage IV, including seven AIDS cases, of whom three had died. Four subjects died of other causes. Only two patients were treated with AZT prior to the occurrence of AIDS. Rate of progression to AIDS was not associated with acute infection, splenectomy, age, or sex. A cumulative AIDS incidence rate of 1.4% (SE 1.3%) was observed at 3 years and of 9% (SE 4%) at 5 years.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Immunoglobulin classes and subclasses of platelet antibodies in a case of post-transfusion purpura.

A multiparous white woman developed severe thrombocytopenia following transfusion of red blood cells. Six ineffective platelet transfusions (a total of 42 random donor concentrates) were given from day 0 to day +6, high-dose steroids from day +1, progressively tapered until day +30, and a total of 150 g of intravenous immunoglobulins from day +2 to day +6. As platelet count had not increased significantly by day +8, four plasma exchange procedures, each consisting of 2,000 ml of plasma exchanged with 5% albumin solution, were performed on days +8, +10, +14 and +18. Platelet count was 5, 50, 100 and 234 x 10(9)/l on days +8, +14, +26 and +32 (discharge), respectively. The patient's acute phase serum contained increased levels of platelet alloantibodies with anti-HPA-1a (PlA1, Zwa) specificity and a titer of 3,200. IgG1, IgG2 and IgG3 subclasses of platelet-reactive antibodies in the patient's serum were elevated, whereas IgG4, IgM and IgA were within the reference values. Levels of IgG1, IgG2 and IgG3 of antiplatelet antibodies showed a marked and parallel reduction during treatment, but were still above the reference values at the end of treatment and 1 year later, when the patient platelet count was normal. Although a failure of intravenous immunoglobulins cannot be proven in this case, plasma exchange seems to have contributed more than intravenous immunoglobulins to clinical remission.

Aged↗
PubMed1992

Platelet concentrates stored in synthetic medium after filtration.

Platelet concentrates prepared from pooled buffy coats (BCPC) were stored in Plasma-Lyte A, a glucose-free synthetic medium, after leukocyte depletion by filtration through Pall PL 50, and compared to paired unfiltered BCPC stored in the same medium. Each pair of BCPC units was prepared from a pool of 10 buffy coats split into two identical units. Platelet and leukocyte counts per unit of BCPC were 2.70 +/- 0.19 x 10(11) and 3.8 +/- 2.8 x 10(6) (filtered BCPC), 2.59 +/- 0.27 x 10(11) and 79 +/- 56 x 10(6) (control BCPC), respectively. Filtration procedures did not affect in vitro parameters of platelet quality and function such as osmotic reversal, ATP release and aggregation in response to collagen and ADP during 15-day storage. A similar decrease of platelet membrane glycoprotein Ib and a similar rise of activation markers GMP-140, gp 53 and platelet-bound fibrinogen were observed during storage of filtered and control BCPC. Our study indicates that storage of BCPC after filtration is feasible and that a reduction in leukocyte content by filtration to mean cell counts of less than five millions per unit has probably no effect on platelet storage lesion.

Adenosine Diphosphate↗
PubMed1991

Transfusion requirements and effects in patients with thalassaemia major. Cooleycare Programme.

Analysis of data available in 1985 on 3468 Italian and Greek patients registered in Cooleycare, an international cooperative programme of quality assessment of treatment delivery in thalassaemia, gave the following picture of treatment requirements and effects. The proportion of patients undergoing splenectomy has progressively decreased, and age at splenectomy has increased with time over the past 20 years. Age at first transfusion exceeds 4 years in a small but important group of patients, which indicates that a milder form of thalassaemia exists in this group. Children receiving modern treatment remain of near-normal stature until age 11 but later tend to be stunted. The mean blood requirement is 35% higher in non-splenectomised than in splenectomised patients. Differences in transfusion interval of 2 to 4 weeks have no measurable effect on blood requirement. Mean blood requirement rises gradually with mean haemoglobin concentration, possibly in a non-linear fashion. The prevalence of red cell alloimmunisation rises with delay in start on transfusion. Transfusion reactions were reported in 1% of transfusions (90% of which were leucocyte-depleted), from 17% of patients.

Adolescent↗
PubMed1990

Removal of white cells from red cells by transfusion through a new filter.

The effectiveness of a new filter (RC100) for the preparation of white cell-depleted red cells (RBCs) at the bedside was evaluated in vitro and in vivo using three RBC products: standard RBC concentrate (CPDA units), RBCs suspended in saline-adenine-glucose-mannitol additive solution after the removal of plasma (SAGM units), and RBCs suspended in SAGM after the removal of plasma and buffy coat (SAGM-BC units). Median RBC recovery was at least 92 percent when 2 units were administered through one filter; median values for residual white cells and platelets were less than or equal to 20 x 10(6) and less than or equal to 2.5 x 10(9) per 2 units, respectively. The in vivo study was carried out in 80 multiply transfused patients with thalassemia, 35 of whom had experienced frequent nonhemolytic transfusion reactions when given standard or buffy coat-free RBCs. During the 6-month study, each patient was given two transfusions of each type of RBC product One febrile nonhemolytic transfusion reaction occurred in each of two patients receiving SAGM-BC units, but in no other case. If the flow rate is not reduced, the median transfusion time is 35 minutes per CPDA unit and 15 minutes per SAGM and SAGM-BC unit. It is concluded that the transfusion of RBCs through the RC100 is a simple and effective procedure to administer white cell-depleted RBCs prepared at the bedside.

Blood Transfusion↗
PubMed1990

Comparison of platelet activation and membrane glycoprotein Ib and IIb-IIIa expression after filtration through three different leukocyte removal filters.

We evaluated three filters used for leukocyte removal from platelet concentrates: Imugard IG 500, Pall PL100 and Sepacell PL-10A. Filter performance, platelet activation and expression of membrane glycoproteins Ib and IIb-IIIa were evaluated. Imugard, Pall and Sepacell showed median postfiltration in vitro platelet recoveries of 88, 84 and 80%, and total residual leukocyte counts of 16.1, 7.5 and 0.6 x 10(6)/pool of 8 platelet concentrates, respectively. Mean platelet volume was reduced after filtration with all filters. Postfiltration values of glycoproteins Ib and IIb-IIIa, and of activation markers GMP 140 and gp 53 were not significantly different from prefiltration values. Filtration through Imugard, Pall and Sepacell did not induce significant platelet activation or modifications of platelet membrane glycoproteins Ib and IIb-IIIa.

Cell Separation↗