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Biomedical subjects

M Valbonesi

Publications and source records attributed to M Valbonesi.

At least 73 records · Page 4Linked to original sources
PubMed1993

Hemopoietic stem cells: technical and methodological considerations.

Peripheral blood cells containing large numbers of granulocyte-macrophage colony forming units (CFU-GM) can be collected by leukapheresis. The number of aphereses needed to collect 2-7 x 10(8) mononuclear cells (MNC)/Kg and 2-50 x 10(4) CFU-GM/Kg during rapid hematopoietic recovery following cytotoxic chemotherapy-induced myelosuppression depends on type of disorder, type of chemotherapy, patients' clinical conditions, cell precounts, concomitant growth factor administration, optimal timing of leukapheresis, vascular access apheresis machines, and type of technique used. Because of the advent of growth factors, a broader window for collection of progenitors has been provided. This has determined an increasing interest for peripheral blood stem cell (PBSC) autotransplants, along with increasing problems due to the number and types of procedures to be performed and the quality and purity of the products. Presently most of the basic technical problems are solved and an array of third generation cell separators is offered for collection of progenitors. Their common features are safety controls, closed circuits, automation, and mechanical and electrical reliability. Performance and quality of the product may be totally different depending not only on the apparatus, but also on the patients' clinical conditions. These technical aspects will be rapidly discussed having in the due considerations the expected increase in the number of procedures.

Bone Marrow Transplantation↗
PubMed1993

Excel: a new cell separator in its very first clinical application.

BACKGROUND: The evolution of technology has been one of the most interesting features that has accompanied thrombocytapheresis throughout the years. In this presentation we report on the preliminary results obtained with Excel, a third-generation cell separator that is presently in its early experimental phase. MATERIAL AND METHODS: So far only 15 thrombocytapheresis procedures, 2 of which of the single-needle type, were carried out on 15 healthy donors processing 4 liters of blood (2.8 liters in single needle). RESULTS AND CONCLUSIONS: The results were satisfactory since the average platelet yield was 4.7 x 10(11). The leukocyte contamination was 0.8 x 10(6) and the RBC contamination 0.4 x 10(7). The platelet efficiency per minute was 6.5 x 10(9), and the run time average 72 min. As to the quality of the product the very first results of platelet aggregation, relative to pre-apheresis, were 78% in response to ADP 6 microM; 106 and 102% in response to collagen 4.5 micrograms/ml and ristocetin 1.5 mg/ml, respectively. Essentially no platelet aggregates were found in the platelet products (Wu-Hoak ratio: 0.91).

Adult↗
PubMed1993

Donors thrombocytapheresis with last generation cell separators.

An exciting, fast moving and promising field remains the use of plasma-free synthetic medium for platelet storage (10, 11), that along with the potential for getting more plasma for therapeutic needs, might also improve the quality of stored platelets. Addition of acetate to solution, may be the way to obtain these results. An astonishing fact is that citrate remains the only anticoagulant for platelet collection, and remains as well the only real cause of donor discomfort during thrombocytapheresis.

Blood Donors↗
PubMed1993

Plasma exchange: the cost/benefit ratio and the critical revision of indications.

The number of conditions that can benefit from Plasma-Exchange (PE) continues to grow. We have recently added to the list the Cyclosporin-A induced hypertrygliceridemia and myoglobinuric acute renal insufficiency. Such as any therapeutic measure for PE, four evolutive phases can be recognized: the discovery and research, the confirmation of indications, the routine applications and the decline, when new more powerful tools are offered by culture or technology. We have participated in the first three phases during the last 20 years. Not necessarily all experiences were favourable. Nonetheless, we feel that, for the time being, a hemapheresis unit is an absolute necessity for a medium - sized hospital even if only therapeutic procedures are carried out. The phase four, decline of interest and applications, cannot be foreseen. Finally the ability of PE to shorten substantially the length of hospital stays along with the ease with which procedure can be performed on ambulatory patients, substantiate a favourable cost/benefit ratio for this therapeutic modality.

Humans↗
PubMed1993

The organization of the autotransfusion-perioperative blood salvage at San Martino Hospital.

Autologous transfusion is playing an important role in modern transfusion medicine. At San Martino hospital we use a combination of manual and mechanical techniques in order to improve autotransfusion procedures, control the hypertransfusion and avoid waste. Our autotransfusion program has determined a 55% reduction in the red cell concentrates used (from 42,000 in 1985 down to 19,400 in 1992). Proper training, cultural improvements and new applications on autotransfusion procedures will permit a better use of blood with less transfusion related complications, until a suitable substitute for blood will be available.

Blood Loss, Surgical↗
PubMed1993

Single-needle thrombo-cytapheresis with the Fresenius AS 104.

BACKGROUND: The Fresenius AS 104 cell separator has recently met some popularity in European apheresis units for the quality of the platelets obtained with the totally automated double-needle procedure. MATERIALS AND METHODS: Taking advantage of the machine's flexibility we have developed a new automated procedure for single-needle thrombocytapheresis (SNP). So far 61 SNP were carried out. From donors having a platelet precount of 2.74 x 10(5) an average of 3.8 x 10(11) cells were collected by processing 2.5 liters of blood in a run time of 83 min. RESULTS AND CONCLUSIONS: The leukocyte and erythrocyte contaminations were 2.7 x 10(7) and 3.5 x 10(7), respectively. Only 2 products did contain less than 3.5 x 10(11) platelets, and 7 procedures were complicated by minor signs of hypocalcemia. With minor modifications this SNP is presently offered on a routine basis to our platelet donors.

Adult↗
PubMed1992

Apheresis for severe malaria complicated by cerebral malaria, acute respiratory distress syndrome, acute renal failure, and disseminated intravascular coagulation.

Malaria has become a very uncommon disease in Italy. Recently a variety of circumstances, such as travel to tropical countries as well as immigration from Asia and Africa, have combined to increase the number of malaria cases recorded annually. In this report we describe the use of red cell exchange transfusion and plasma exchange in the treatment of a patient with hyperparasitemic malaria (51% erythrocytes or more parasitized). When first observed the patient was in shock and had signs of cerebral malaria, disseminated intravascular coagulation, and acute respiratory distress syndrome, which in the following 2 days were complicated by acute renal failure. After mefloquine therapy combined with 3 red blood cell exchanges, 2 plasma exchanges, and 10 dialysis sessions over 14 days, the patient recovered completely. This case of severe malaria with multiple complications, treated with mefloquine in conjunction with both exchange transfusion and plasmapheresis, had a successful outcome and lends further support to the possible beneficial role of exchange transfusion in complicated malaria.

Acute Disease↗
PubMed1992

Intensive conventional chemotherapy can lead to a precocious overshoot of cytogenetically normal blood stem cells (BSC) in chronic myeloid leukemia and acute lymphoblastic leukemia.

Forty patients with Ph-positive blastic phase (BP) (28 patients) or chronic phase (CP)-CML (3 patients) and relapsed adult acute lymphoblastic leukemia (ALL) (9 patients) with cytogenetical translocations [t(8;14):2 patients; t(4;8):2 patients; t(4;11):3 patients; t(9;22):2 patients], received an intensive conventional chemotherapy. During early recovery from marrow aplasia, when WBC reached 0.3-1.5 x 10--9/L, peripheral blood stem cells (BSC) were collected by 4-8 leukapheresis consecutively. BSC collected from the 2/3 patients with CP-CML resulted Ph-negative and PCR negative. In 8 out of 26 BP-CML patients, BSC resulted Ph-negative and in two cases PCR negative. Of the nine ALL patients, 6 patients lost the cytogenetic translocations, one patient died during aplasia, two patients did not have cytogenetic modifications and died in few weeks of leukemia and one patient out of six responding patients relapsed before transplant. After complete recovery, 15 patients (BP-CML:8 patients; CP-CML:2 patients; ALL:5 patients) were subsequently given high-dose therapy (VP-16 +/- Cy+TBI in single dose) followed by reinfusion of "normal" BSC. Both the patients in CP-CML and 5/5 patients with ALL maintain clinical and cytogenetic remission; all the patients transplanted in BP-CML relapsed 5-18 months post-transplant. It is concluded that intensive conventional chemotherapy employed in CML and ALL can lead to a precocious overshoot of cytogenetically normal BSC.

Adolescent↗
PubMed1991

Plateletpheresis with the new Fresenius AS 104 blood cell separator.

Among the many blood cell separators introduced into the international market in these last few years, the Fresenius AS 104 represents an advanced and safe thrombocytapheresis machine whose development took advantage of extensive worldwide experience with blood cell separation. Nonetheless the AS 104 has generated most interest in West Germany and most, if not all, the studies published on its platelet collection efficiency have been carried out in that country. It is normally reported that from 2.7 to 3.5 x 10(11) platelets can be collected in approximately 80 minutes. Since these results could not be duplicated routinely in our hemapheresis unit, we set up a study by modifying the standard procedure. It was possible to reduce the procedure time and to collect platelet concentrates containing more than 4 x 10(11) cells on a routine basis by using the following procedure: ACD-A/blood ratio 1:10; Interface position 6:2; blood flow rate always exceeding 65 mL/min; rpm 1750; cell collection from 4 to 7 mL/min; volume of blood processed 3.6 L followed by the rinsing of the system with 200 ml of saline; extraction of the content of the secondary separation chamber by the action of the plasma pump working at 20 mL/min for 2 min. With this procedure the platelet yield in 34 collections exceeded 3.1 x 10(11) and averaged 4.06 x 10(11). The procedure time was reduced to 56.5 minutes with a mean blood flow rate of 62.3 mL/min. The leukocyte and erythrocyte contamination of the products were in the range of 1 x 10(7) and 1 x 10(8) respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Evaluation Studies as Topic↗
PubMed1991

Cyclosporin-induced hypertriglyceridemia with prompt response to plasma exchange therapy.

A case of severe cyclosporin-induced hypertriglyceridemia that prompted plasma exchange therapy is reported. Hyperlipemic retinitis, headache, stupor, and peripheral paresthesias became apparent when the level of triglycerides exceeded the 1,500 mg/dL level. Two plasma exchanges were required to halt disease progression. This is the second time that plasma exchange was used in a bone marrow transplanted patient on cyclosporin-A therapy. In both cases hypertriglyceridemia became apparent and symptomatic after approximately 7 months of therapy with cyclosporin.

Adolescent↗
PubMed1991

Therapy of acute phase chronic myelogenous leukemia with intensive chemotherapy, blood cell autotransplant and cyclosporine A.

The expansion of the Philadelphia (Ph) chromosome positive clone in chronic myeloid leukemia (CML) may depend on its capacity to suppress the proliferation of Ph-negative stem cells, but this proliferative advantage might, in certain circumstances, be reversible. Various lines of evidence suggest that Ph-negative cells, albeit in a suppressed state, must still be present. As recently suggested, the expansion of 'putative' normal Ph-negative hemopoietic stem cells might have, in certain circumstances, a proliferative advantage over the Ph clone in CML. This suggests that the treatment of CML with intensive chemotherapy might allow the collection of Ph-negative hemopoietic cells in the early phase of recovery. Eight patients with acute phase chronic myelogenous leukemia (AP-CML) were treated with idarubicin, intermediate dose cytarabine and etoposide. During recovery from bone marrow aplasia, when the white blood cell count reached 0.3-1 x 10(-9), blood cells were collected with 2-5 (median 3) consecutive leukapheresis. In 5/8 patients, these peripheral cells were Ph-negative at the cytogenetic analysis. Moreover, in one case the polymerase chain reaction analysis performed to detect the presence of minimal residual disease in the cells collected by leukapheresis was negative, further confirming that this approach may induce a very high degree of suppression of the Ph-positive clones. After complete recovery, these five patients were subsequently treated with high-dose etoposide, cyclophosphamide and total body radiation (10 Gy, single dose) followed by reinfusion of Ph-negative peripheral blood stem cells. All these patients received cyclosporine A post-autotransplant in an attempt to induce acute graft-versus-host-disease. Three of 5 patients remain in clinical and cytogenetic remission 5-15 months post-transplant. It is concluded that Ph-negative peripheral blood stem cells can be recovered from patients with AP-CML and used successfully to restore Ph-negative hemopoiesis after high dose therapy.

Adult↗
PubMed1990

Intraoperative blood salvage.

Interest in and use of IBS have increased recently. This form of haemotherapy involves the retrieval of blood shed perioperatively. IBS, together with other forms of ABT, has gained a prominent role in transfusion medicine, largely due to an increased awareness of the risks associated with transfusion of homologous blood. In addition to conserving erythrocytes, IBS prevents disease transmission, other adverse transfusion reactions, and alloimmunization to antigens in blood cells and plasma which may result from homologous blood use. An array of IBS devices is presently available, ranging from disposable canisters to complete processing systems. The devices are capable of recovering, filtering, washing and reinfusing shed erythrocytes. They can be divided into slow-flow and rapid-flow systems based on the rapidity of blood processing. Most systems use a dual channel aspiration cannula through which shed blood is aspirated and mixed with anticoagulant solution. The salvage procedure requires operator control at every step, even for the highly automated instruments. Various health care personnel have been trained to operate IBS equipment; a transfusion service nurse with blood bank expertise has proved to be a highly reliable operator in our practice. Extensive clinical observation has shown that salvaged erythrocytes function and survive normally. IBS has been applied in many surgical fields; it has two relative contraindications: its use in areas affected by infection or malignancy. Operative procedures characterized by large blood losses provide a cost-efficient application of IBS, including cardiac surgery, orthopaedic procedures, trauma, vascular surgery, and liver transplantation. New, highly efficient technology is emerging that is capable of recovering other blood components. Consequently, what presently amounts to erythrocyte recovery will be expanded shortly to include platelets and plasma, with its many constituents.

Blood Transfusion, Autologous↗
PubMed1988

Plateletpheresis concentrates produced in 30 minutes along with plasma and packed red cells: preliminary results.

Centrifugal devices for donor plasmapheresis that collect platelets as a by-product have recently been introduced. The platelet yield ranges from 1.2 to 2 X 10(11) per collection, and the collection time exceeds 50 minutes. An attempt to increase yields and to reduce the procedure time was carried out at our center, taking advantage of the Dideco Eccentriplate (Dideco spa, Mirandola, Italy). Within 30 minutes, 510 ml of plasma were collected along with 3.3 X 10(11) platelets. The shift of donors from whole blood to plasma and platelet donation generated a progressive decrease in red-cell availability. In order to maintain plasma and platelet production without affecting the erythrocyte production, a technique was developed that allows the collection of 3.68 X 10(11) platelets, 250 ml of plasma, and 225 ml of packed red blood cells with a hematocrit of 66.5%. The mean procedure time was 31.6 minutes; 2,671 ml of blood were processed at flow rates of 85-100 ml/minute. The cellular cross contamination of the platelet concentrates was 1.76 X 10(8) (leukocytes) and 2.23 X 10(8) (erythrocytes). Although the procedure was carried out in a selected group of donors, the technical experience has strongly modified our procedure for platelet and plasma collection.

Blood Component Removal↗
PubMed1988

New application of the autotrans: autologous support of the organ donor and salvage of the donor's red blood cells for the transfusion support of organ recipients.

Organ donation is usually limited to solid tissues; paradoxically, organ donors undergoing explant are often transfused in preparation for or during surgery. This practice increases the requirement for blood and adds immunological and infectious risks for both recipients and donors of grafts. We have investigated the possibility of supporting an explant with intraoperative blood salvage and, in the case of a cadaver donor, at the end of the operation, salvaging blood for potential use in the graft recipient. This preliminary report describes the technique and the results obtained in two procedures. The volume of red cells with a hematocrit of 55% obtained from the two donors was 2,090 and 1,180 ml, respectively. These components were employed for the transfusion support of the organ recipients.

Blood Component Removal↗