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Biomedical subjects

P Rebulla

Publications and source records attributed to P Rebulla.

At least 55 records · Page 3Linked to original sources
PubMed1998

Serum ferritin, desferrioxamine, and evolution of HIV-1 infection in thalassemic patients.

To study the respective roles of mean serum ferritin level and the mean desferrioxamine (DFX) dose on progression of HIV-1 infection, data from 49 HIV-seropositive thalassemic patients were analyzed using a Cox proportional hazards model including known confounding variables. Nine years after seroconversion, 10% of those who had been prescribed >40 mg/kg of DFX daily had entered stage IV versus 39% of those who had been prescribed a lower dose. Patients with ferritin level >1935 g/L entered stage IV more rapidly than those with a lower level (31% versus 16%). In multivariate analysis, the ferritin level was found to be an independent predictor of progression of HIV disease, whereas the mean daily dose of DFX was not. Similar results were obtained when death was the endpoint. Our results support a hypothesis that was recently expressed, that iron overload could be associated with a more rapid progression of HIV-1 infection.

Child↗
PubMed1998

The current risk of retroviral infections transmitted by transfusion in patients who have undergone multiple transfusions. Cooleycare Cooperative Group.

BACKGROUND: To conduct a multicenter, prospective survey within the program of the Cooleycare Cooperative Group to evaluate the rate of transfusion-transmitted infections with human immunodeficiency virus (HIV) and human T-lymphotropic virus (HTLV) in a cohort of patients who were homozygous for beta thalassemia and underwent multiple transfusions during the 6-year follow-up. PATIENTS AND METHODS: One thousand three hundred eighty-four patients with beta thalassemia from 36 centers were enrolled from December 1989 to March 1990. Serum samples were tested at regular intervals during the period from December 1989 to March 1996 for anti-HIV and anti-HTLV antibodies in 1 laboratory. Samples from 1073 and 1001 of the 1384 patients were available for evaluation also during the periods from December 1992 to March 1993 and December 1995 to March 1996, respectively. The risk of acquiring infection was calculated by the ratio between the number of patients who experienced seroconversion and the number of red blood cell units administered to the patients during the study period. RESULTS: The prevalence of HIV infection found in the period from December 1989 to March 1990 was 2.9% (40 of 1384 patients). During follow-up, 1 of 1001 patients showed anti-HIV seroconversion. The incidence of HIV infection was 1.7 per 10,000 person-years (upper boundary of the 95% confidence interval, 5 per 10,000). The risk of HIV infection was 1 in 190,000 U (upper boundary of the 95% confidence interval, 1 in 67,000). At baseline, 4 patients were infected with HTLV (3 with HTLV-1 and 1 with HTLV-2). No seroconversions were observed during follow-up; the risk of HTLV infection was less than 1 in 190,000 U. CONCLUSION: The application of reliable screening procedures for donor selection reduced the transmission of transfusion-associated HIV infection in 1989-1995 to fewer than 2 cases in 10,000 person-years or 1 case per 190,000 units of red blood cells.

Adolescent↗
PubMed1998

The incidence and natural course of transfusion-associated GB virus C/hepatitis G virus infection in a cohort of thalassemic patients. The Cooleycare Cooperative Group.

To evaluate the risk of transmitting blood-borne GB virus C/hepatitis G virus (GBV-C/HGV) and to define the natural course of infection, we performed a prospective study in a cohort of multitransfused beta-thalassemics during a 6-year follow-up period. We analyzed serum samples of 150 patients collected at 3-year intervals from 1990 to 1996. GBV-C/HGV RNA was determined by reverse transcriptase-polymerase chain reaction and antibodies to E2-protein by an enzyme immunoassay. At baseline, 14.5% of patients had viremia and 18.5% anti-E2. None of the patients with anti-E2 in 1990 subsequently became viremic. Of the 100 GBV-C/HGV RNA-, anti-E2- patients, 10 acquired infection during follow-up, as indicated by positivity of GBV-C/HGV RNA (n = 2), anti-E2 (n = 7), or both markers (n = 1) in 1996. The incidence was 1.7 per 100 person-years (95% confidence interval [CI], 0.8 to 3). Since approximately 19,000 blood units were transfused to these patients during follow-up, the risk of infection was 5.3 in 10,000 units (95% CI, 2 to 8.5). Six of 22 viremic patients cleared the virus during follow-up; 4 of them became anti-E2+. Twelve of 28 patients lost anti-E2 reactivity during follow-up. In conclusion, more than 25% of infections resolve within 6 years; the presence of anti-E2 seems to be protective against infection. Anti-E2 reactivity may decrease with time.

Adolescent↗
PubMed1998

Evaluation of a new automated instrument for pretransfusion testing.

BACKGROUND: A number of automated devices for pretransfusion testing have recently become available. This study evaluated a fully automated device based on column agglutination technology (AutoVue System, Ortho, Raritan, NJ). STUDY DESIGN AND METHODS: Some 6747 tests including forward and reverse ABO group, Rh type and phenotype, antibody screen, autocontrol, and crossmatch were performed on random samples from 1069 blood donors, 2063 patients, and 98 newborns and cord blood. Also tested were samples from 168 immunized patients and 53 donors expressing weak or variant A and D antigens. Test results and technician times required for their performance were compared with those obtained by standard methods (manual column agglutination technology, slide, semiautomatic handler). RESULTS: No erroneous conclusions were found in regard to the 5028 ABO group and Rh type or phenotype determinations carried out with the device. The device rejected 1.53 percent of tests for sample inadequacy. Of the remaining 18 tests with discrepant results found with the device and not confirmed with the standard methods, 6 gave such results because of mixed-field reactions, 10 gave negative results with A2 RBCs in reverse ABO grouping, and 2 gave very weak positive reactions in antibody screening and crossmatching. In the samples from immunized patients, the device missed one weak anti-K, whereas standard methods missed five weak antibodies. In addition, 48, 34, and 31 of the 53 weak or variant antigens were detected by the device, the slide method, and the semiautomated handler, respectively. Technician time with the standard methods was 1.6 to 7 times higher than that with the device. CONCLUSION: The technical performance of the device compared favorably with that of standard methods, with a number of advantages, including in particular the saving of technician time. Sample inadequacy was the most common cause of discrepancy, which suggests that standardization of sample collection can further improve the performance of the device.

ABO Blood-Group System↗
PubMed1998

Implementation of a quality system (ISO 9000 series) for placental blood banking.

Although placental blood has recently become a new source of hematopoietic progenitors for marrow replacement, limited attention has been given to systems suitable to ensure the short-term and long-term quality of placental blood units used for transplantation. In this article, we describe a quality system for placental blood banking developed in accord with ISO 9002 norms at Milano Cord Blood Bank. The quality system is the organizational structure, procedures, processes, and resources needed to implement quality management. ISO 9002 is a model for quality assurance in production, installation, and servicing, which includes a number of clauses providing guidance for the implementation of the quality system. The quality system was started by the bank medical director with step 1: the general quality plan, which included (a) the written description of mission, objectives, technical and organizational policies, and staff organization chart of the placental blood bank, (b) the definition and acquisition of adequate financial, human, and structural resources, (c) the appointment of a quality system head independent from the production laboratory and reporting directly to the medical director. Tasks of the quality system head were (a) to identify the placental blood banking process together with the placental blood bank personnel, (b) to implement a documentation plan finalized at the production and maintenance of (i) the quality manual, which provides a summary on how the bank operates with a quality system in compliance with the ISO 9002 clauses, (ii) the general procedures (or quality system procedures), which provide more detail on selected clauses, including at least those prescribed by the ISO 9002 standard, (iii) the operative procedures (or process procedures), which describe in detail the process of placental blood banking and how technical activities must be performed, (iv) the work instructions, which provide stepwise descriptions of individual activities, (v) records/forms for data collection and storage, (c) to identify quality indicators, (d) to start a regular internal audit, (e) to report audit results to the medical director for review. This was followed by step 2: the job descriptions, staff training, and qualification; step 3: the documentation plan; step 4: the internal audit plan; step 5: the launch of the quality system, and step 6: the assessment by an external team from an accredited third-party organization and final certification for compliance to ISO 9002. The quality system, which must be maintained and undergo external audit at regular intervals so that certification is confirmed, ensures the high probability that placental blood units provided to clinicians conform regularly to predefined levels of quality.

Blood Banks↗
PubMed1998

In vitro and in vivo properties of various types of platelets.

The most popular procedures used to prepare platelet concentrates (PC) can be categorized into methods using platelet rich plasma (PRP) obtained by soft centrifugation of whole blood units, methods using buffy coats (BC) obtained by hard centrifugation of whole blood units, and apheresis procedures. The main feature that differentiates apheresis PC from whole blood unit derived PC is that apheresis reduces the number of donors necessary to support a recipient, although the advantages related to this feature have not been conclusively documented. From the biochemical point of view, a limited number of comparative studies and a large series of non-comparative studies indicate that differences in PC obtained with different protocols depend more on the performances of the production laboratory rather than the preparative approach--PRP, BC or apheresis--itself. Similarly, the clinical effectiveness of PC seems to depend more on PC age, storage modalities and recipient's conditions rather than primarily on the method of PC preparation. Despite the basic differences in the three preparative approaches, all methods share a number of key elements that are necessary pre-requisites for a successful platelet transfusion therapy: minimization of the risk of bacterial contamination by careful donor skin disinfection and temperature control during PC production and storage; protection of aerobic metabolism during PC storage; laboratory quality control including at least pH and volume determinations, platelet and white cell counts and visual inspection of the swirling phenomenon at time of release. Future directions in the field of PC production include the development of new products such as infusible platelet membranes, thrombospheres, thromboerythrocytes and reconstituted freeze-dried platelets.

Adult↗
PubMed1998

Cadaver kidney allocation in the north Italy transplant program on the eve of the new millennium.

The identification of parameters impacting on cadaver kidney graft outcome is of paramount importance to ensure proper organ allocation, a process that must take into account ethical, biological, social and administrative factors. This is particularly critical in countries where organ procurement is largely insufficient. In the present chapter we report the results of studies carried out to determine the impact of 17 factors on graft survival and function at 4 years posttransplant in 2,917 recipients transplanted from January 1990-September 1997 in the North Italy Transplant program (NITp). Patient and graft survival rates at 4 years (+/- SEM) were 93.5 +/- 0.5% and 81.4 +/- 0.8%, respectively. Excellent graft function at 4 years was shown by 69.8% of recipients. Younger donor age, absence of pretransplant transfusions, patient dialysis center in the NITp area and level of HLA match showed a statistically significant positive association with graft survival. Younger donor age and male donor gender showed a statistically significant association with excellent graft function at 4 years. These global outcomes were confirmed when the analysis was limited to the subset of the 2,617 adult recipients and to the subset of 1,211 cases for whom both donor and recipient HLA-DRB1 types were available before transplant. The results were used to develop a computer-assisted, refined version of the NITp adult kidney allocation algorithm that was named NITK3. A preliminary evaluation of 472 transplants allocated in 12 months with NITK3 compared with 459 transplants allocated in the preceding 12 months according to the previous algorithm (NITK2) showed a significantly higher proportion of recipients who had been on the waiting list for more than 3 years (33.1% vs 21.1%). The use of NITK3 was also associated with a significantly increased ability to transplant alloimmunized patients (17.7% vs 9.5% with NITK2) and recipients with 0-1 HLA mismatches (21.2% vs 13.5% with NITK2). Differences in 6-month graft survival rates and in the percentage of patients with excellent function at 6 months were not statistically significant in recipients transplanted with NITK3 versus NITK2. Survival rates were 96.9% and 92.4%, respectively. Percentages of patients with excellent renal function were 68.3% and 70.5%, respectively. These preliminary data suggest that NITK3 improves HLA match and reduces the number of patients on the waiting list for 3 or more years without determining significant modifications of 6-month graft survival and function. Moreover, it facilitates the achievement of a fair local balance between organs retrieved and transplanted, the compliance of operators with objective allocation rules and the documentation of the whole allocation process.

Adolescent↗
PubMed1998

A quality system for placental blood banking.

A Quality System for Placental Blood Banking aimed at the transplantation of haematopoietic stem cells to related and unrelated allogeneic recipients is described. It includes the organizational structure, procedures, processes and resources needed to implement quality management. The Quality System described in this article is based on ISO 9002, a model for quality assurance in production, installation and servicing developed in 1987 and revised in 1994 by the International Organization for Standardization. ISO 9002 includes 20 clauses that provide guidance for the implementation of the Quality System. The development of the Quality System is started by the Placental Blood Bank Medical Director with the definition of a General Quality Plan including: (1) the written description of the Mission, Objectives, Technical and Organizational Policies, and Staff Organization Chart; (2) the definition and acquisition of adequate financial, human and structural resources; (3) the appointment of a Quality System Head, who must identify the Placental Blood Banking process together with the Placental Blood Bank personnel; implement a documentation plan; identify quality indicators; start regular internal audit; report audit results to the Medical Director for review. Following staff training and qualification, the Quality System is launched. The Placental Blood Bank can then undergo audit by an external inspector and be finally certified for compliance to ISO 9002. The Quality System must be maintained and subjected to external audit at regular intervals so that certification is confirmed.

Blood Banks↗
PubMed1997

The threshold for prophylactic platelet transfusions in adults with acute myeloid leukemia. Gruppo Italiano Malattie Ematologiche Maligne dell'Adulto.

BACKGROUND: Prophylactic platelet transfusions are usually administered to patients receiving myelotoxic chemotherapy when their platelet count falls below 20,000 per cubic millimeter. Some observations suggest that lower platelet counts can be appropriate in patients in stable condition, but the safety of lower thresholds is uncertain. METHODS: We evaluated 255 adolescents and adults (age, 16 to 70 years) with newly diagnosed acute myeloid leukemia (but not acute promyelocytic leukemia), who were treated in 21 centers. One hundred thirty-five patients were randomly assigned to receive a transfusion when their platelet count fell below 10,000 per cubic millimeter (or 10,000 to 20,000 per cubic millimeter in those with a temperature above 38 degrees C, with active bleeding, or a need for invasive procedures), and 120 patients were assigned to receive a transfusion when their platelet count was less than 20,000 per cubic millimeter. RESULTS: Patients in the group with a threshold of 10,000 platelets per cubic millimeter received 21.5 percent fewer platelet transfusions than the patients in the group with a threshold of 20,000 platelets per cubic millimeter (P=0.001). The numbers of red-cell units transfused were not significantly different between groups. Major bleeding (defined as any bleeding more than petechiae or mucosal or retinal bleeding) occurred in 21.5 and 20 percent of patients, respectively (P=0.41), and on 3.1 and 2.0 percent of the days of hospitalization. One episode of fatal cerebral hemorrhage occurred in the group with a threshold of 10,000 platelets per cubic millimeter; none occurred in the other group (P= 0.95). Actuarial estimates of survival during induction chemotherapy, actuarial estimates of the absence of major bleeding, and the length of hospital stay were not significantly different in the two groups. CONCLUSIONS: The risk of major bleeding during induction chemotherapy in adolescents and adults with acute myeloid leukemia (except acute promyelocytic leukemia, which we did not study) was similar with platelet-transfusion thresholds of 20,000 per cubic millimeter and 10,000 per cubic millimeter (or 10,000 to 20,000 per cubic millimeter when body temperature exceeded 38 degrees C, there was active bleeding, or invasive procedures were needed). Use of the lower threshold reduced platelet use by 21.5 percent.

Adolescent↗
PubMed1997

Use of photografting technique for the immobilization of blood-grouping antibodies onto microtiter plates.

Commercial anti-A, anti-B, anti-A,B and anti-D monoclonal and polyclonal antisera were immobilized onto polystyrene microtiter plates using a photografting technique, to set up a new solid-phase assay (SPA) to be used for blood grouping. The reactivity and specificity of each grafted antisera were studied using red blood cells (RBCs) expressing normal and weak antigens. The stability of immobilized antisera was also studied. After dry storage of plates at +4 degrees C, room temperature, and +37 degrees C, SPA was performed using fresh and/or frozen RBCs. The same test was carried out after storing plates under protective conditions. Concordance of collected with expected results was obtained in all cases when the SPA was performed using monoclonal antisera and RBCs, with normal or weak expression of ABO and D antigens immediately after plate preparation or after dry storage at +4 degrees C. Plates stored dry at room temperature or at +37 degrees C gave inconsistent results, whereas a slight increase in reactivity was observed after storage under protective conditions. The specificity and the reactivity of tested antibodies were not modified by the immobilization procedure, not even after dry storage at +4 degrees C. Damage produced by water evaporation during dry storage in hard conditions could be reduced by adding a protective solution to microtiter wells at the beginning of storage.

ABO Blood-Group System↗
PubMed1997

Use of SERVQUAL to assess clinicians' satisfaction with the blood transfusion service.

BACKGROUND AND OBJECTIVES: Limited information is available on the level of satisfaction of clinicians with services delivered by blood banks. The purpose of this study was to evaluate the satisfaction of clinicians with our blood transfusion service. MATERIALS AND METHODS: We prepared a questionnaire based on SERVQUAL, a method used to measure customers' appreciation of quality of service, by assessing the gap between perceived and expected quality. The questionnaire consisted of 14 items grouped according to five dimensions of quality of service: assurance, empathy, responsiveness, reliability, tangibles. Clinicians were asked to give two scores on a scale from 1 to 7 for each item, score (e) representing what they expected from an 'excellent' service, score (r) how they graded the service received. We considered wide differences in scores of service expectation and receipt for a question to be indicative of either service above expected levels (r > e) or service below expectation (r < e); similar scores for both expected and received service (within 1 point on the grading scale) were taken to indicate that the service received was that which was expected. RESULTS: A total of 184 questionnaires (49%) were returned. For the 14 items considered, the proportion of clinicians expressing levels of satisfaction similar to or above expectation ranged from 67 to 96%. Three critical areas, which clinicians considered important (expectation scores 6-7) were associated with satisfaction below expectation in more than 20% of responders. They were: clarity of procedures, clarity of blood request forms, and convenience of blood request and issuing times, which were rated as important by 77, 80 and 72% of clinicians, respectively. CONCLUSION: SERVQUAL was useful to gather information on the level of clinicians' satisfaction with our transfusion service.

Ancillary Services, Hospital↗
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↗