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Objective: Nontunneled central venous catheters (CVCs) have been found an excellent cost-effective alternative to tunneled CVCs with comparable durability and safety when managed by a specialized team. The objective of this study was to evaluate the complications related with a nontunneled polyurethane CVC in a medium-size hospital without such dedicated services.

Patients and methods: A representative sample of 82 cancer patients with 123 nontunneled CVCs inserted at our centre were followed up and evaluated clinically and microbiologically. Insertion and care were performed by the medical and nursing teams.

Results: The mean duration of the catheters in place was 28.2 days. Eleven mechanic complications (8.9%) were observed. We had a total of 3,380 days of catheter use with an infection rate of 0.86 per 100 catheter-days. Staphylococcus coagulase-negative was the most common microorganism isolated. Local and systemic infection showed a different pattern of incidence, early after insertion and a month later respectively. Male sex and neutropenia at catheter removal were the only risk factors for bacteremia while receiving antibiotics at insertion date was a protecting factor. Age, number of lumens, insertion difficulty or patient diagnosis were not related with infection risk.

Conclusions: Contamination at catheter insertion clinical or manipulation must be avoided especially when a neutropenia period is expected. A highly trained team working under rigorous guidelines is an important factor for optimal clinical and economic results with nontunneled CVCs. The cost of a specialized infusion team may well be below the price of poorly maintained catheters.

Purpose: To detect and quantify by flow cytometry (FC) PNH clones in paroxysmal nocturnal haemoglobinuria (PNH) and aplastic anaemia (AA) patients.

Patients and methods: We have performed a flow cytometric analysis to determine the granulocyte expression of CD55 and CD59 from 29 patients with AA and 11 patients with PNH.

Results: In the 11 PNH patients the study showed 58 +/- 34% and 56 +/- 32% (mean +/- SD) CD55(-) y CD59(-) granulocytes. A good correlation was found between the results of FC and haemolysis. The follow-up study showed PNH clone progression in one case and stability in 5 cases. Among 11 AA patients studied at diagnosis, two presented a population of CD55(-) granulocytes (14% and 48%) with CD59 normal, this defect disappeared in both patients after immunosuppressive therapy. The FC study revealed PNH clones in 7 cases among the 26 analyzed after treatment (23 with ATG and/or CyA), in 3 cases with negative Ham's test (in two this became positive 6 and 12 months later). The mean values obtained in these 7 patients with PNH-AA syndrome were 26 +/- 15% y 36 +/- 30% (mean +/- SD) CD55(-) and CD59(-) granulocytes. The median time from diagnosis to detection of PNH phenomenon was 83 months. In the follow-up study, 4 cases had stability, one case had a decrease and one a progression of the abnormal clone. In a retrospective analysis, among the 7 patients with PNH-AA syndrome, 5 had a partial response after the initial treatment.

Conclusions: The FC on granulocytes is a useful method to diagnose and characterize PNH. This test is good for early detection of PNH clones in AA patients at initial diagnosis and in long term survivors. In both diseases it permits measuring the extent of the abnormal clone and its follow up. The extent of the defect is more related to haemolysis than the haematopoietic deficiency. PNH development seems to be more frequent in AA patients with incomplete response after immunosuppressive therapy and in some cases the defect could be latent at the time of diagnosis.

Purpose: Long-term therapy of haematology patients has been facilitated by permanent indwelling central venous catheters. We performed a retrospective study to compare the problems occurring with a externalized catheter (Hickman) versus a totally implanted port catheter.

Patients and methods: A total of 171 catheters were placed to 139 haematological patients, 77 patients with Hickman catheters and 94 with totally implanted port catheters. We review our experience in order to identify factors associated with complications.

Results: Pneumothorax occurred in one of 171 of the percutaneously placed devices. Other early complications were hematoma 13, and catheter migration out of the vascular tree 8. Late complications included malposition (5.8%), thrombosis (2.9%), septic thrombosis (1.7%) and most notably infection (38.5%). 62 of 77 patients with Hickman catheters developed catheter-related infection (hazard rate infection 7.1/1000 days) compared with 53 of 94 patients with implanted port catheters (hazard rate infection 1.5/1000 days, p < 0.001). Most of infections that occurred were caused by gram-positive organisms but the gram-negative organisms infections resulted in a significantly higher rate of treatment failure and recurrence. A total of 72 catheters were removed of the central line: 36 for infection.

Conclusion: We found a significantly increased incidence of catheter-related infection in patients with Hickman catheters. We also observed that the use of intravenous antibiotic prophylaxis prior to catheter insertion did not appear to be beneficial and thrombocytopenia at this moment was a factor in the development of hematoma. The infections due to coagulase-positive staphylococci can be treated successfully without removal of the catheters. However in catheter-related bacteremia due gram-negative organisms there is a chance that the bacteremia will recur if the catheter is not removed.

Objective: To demonstrate that the enzyme L-asparaginase from Escherichia coli (EcA) binds to the plasma membranes of normal human lymphocytes and monocytes.

Material and methods: Lymphocytes and monocytes were isolated from heparinized blood samples which came from healthy volunteer donors. The cells were incubated with EcA to detect a possible binding of the enzyme to the mononuclear cells by indirect immunofluorescence using confocal microscopy. Meanwhile, ultracentrifugation was used to obtain the erythrocyte ghost microsomal fraction (P100) which was then analyzed by Western blotting to determine if EcA binds the lipid bilayer unspecifically. For the immunoassays, monospecific polyclonal antibodies were obtained from ascitic tumors developed in mice immunized with commercial L-asparaginase.

Results: EcA bins the lymphocyte and monocyte plasma membranes. In monocytes, there occurs a capping phenomenon, that is, the accumulation of fluorescent marker in one region. The image analyzer highlights it clearly at a depth of 3.8 microns. This binding would be unspecific, that is, there is no mediation of a specific receptor that binds EcA. This arises from the ability of the enzyme to bind to the membranes of erythrocyte ghost, as evidenced by the ability of the molecule to associate with a hydrophobic medium. The antibodies against EcA obtained from ascitic tumours developed in mice do not show cross reactivity with Na+/K+ ATPase, aspartate aminotransferase, nor with extracts of blood cells, which would make it a specific tool for the detection of EcA in whole cells and in homogenates electrotransfered to nitrocellulose membranes.

Conclusion: L-asparaginase from E. coli behaves as a lipoprotein due to its ability to insert itself into hydrophobic environments, in which it resembles an isozyme present in T. pyriformis. The binding of this enzyme to lymphocytes and monocytes, demonstrated in this work, would permit the modification of the antileukemic treatment injecting doses of EcA bound to patient's own isolated immune cells.

Purpose: To analyse the immunophenotype of leukaemic cells in a group of children diagnosed of lymphoblastic leukaemia in order to assess the frequency of the different immunologic subtypes.

Patients and methods: In the period comprised between APR 1987 and MAR 1995, 402 Mexican children were studied in a prospective way. Conventional immunological markers were used, either associated to or specific for B, T, myelo-monocytic or megakaryocytic-platelet cell populations.

Results: Five major immunologic subtypes were disclosed, showing a series of specific surface markers: null-ALL, 5%; early pre-B, 7.5%; common, 74.6%; B-cell, 3.5%, and T-cell, 9.4%. A net predominance of B-cell precursor CD10- ALL was found in children under one year of age, and of CD10+ B-cells beyond that age. Although there was only slight predominance of male sex, the prevalence of B and TALL in males was not confirmed.

Conclusions: These results show that the incidence of the different immunologic subtypes of lymphoblastic leukaemias and their distribution according to age and sex are closely similar to those reported among Caucasians in other parts of the world.