34 research outputs found

    Early and extensive CD55 loss from red blood cells supports a causal role in malarial anaemia

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    BACKGROUND\ud \ud Levels of complement regulatory proteins (CrP) on the surface of red blood cells (RBC) decrease during severe malarial anaemia and as part of cell ageing process. It remains unclear whether CrP changes seen during malaria contribute to the development of anaemia, or result from an altered RBC age distribution due to suppressive effects of malaria on erythropoiesis.\ud \ud METHODS\ud \ud A cross sectional study was conducted in the north-east coast of Tanzania to investigate whether the changes in glycosylphosphatidylinositol (GPI)-anchored complement regulatory proteins (CD55 and CD59) contributes to malaria anaemia. Blood samples were collected from a cohort of children under intensive surveillance for Plasmodium falciparum parasitaemia and illness. Levels of CD55 and CD59 were measured by flow cytometer and compared between anaemic (8.08 g/dl) and non- anaemic children (11.42 g/dl).\ud \ud RESULTS\ud \ud Levels of CD55 and CD59 decreased with increased RBC age. CD55 levels were lower in anaemic children and the difference was seen in RBC of all ages. Levels of CD59 were lower in anaemic children, but these differences were not significant. CD55, but not CD59, levels correlated positively with the level of haemoglobin in anaemic children.\ud \ud CONCLUSION\ud \ud The extent of CD55 loss from RBC of all ages early in the course of malarial anaemia and the correlation of CD55 with haemoglobin levels support the hypothesis that CD55 may play a causal role in this disorder

    Regulation of human erythrocyte glyceraldehyde-3-phosphate dehydrogenase by ferriprotoporphyrin IX

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    Erythrocyte glyceraldehyde-3-phosphate dehydrogenase (G3PD) is a glycolytic enzyme containing critical thiol groups and whose activity is reversibly inhibited by binding to the cell membrane. Here, we demonstrate that the insertion of ferriprotoporphyrin IX (FP) into the red cell membranes exerts two opposite effects on membrane bound G3PD. First, the enzyme is partially inactivated through oxidation of critical thiols. Dithiothreitol restores part of the activity, but some critical thiols are irreversibly oxidized or crosslinked to products of FP-induced lipid peroxidation. Second, G3PD binding to the membrane is modified and the enzyme is activated through displacement into the cytosol and/or release from its binding site

    Testing of microbial contamination during the preparation of the radiocompound [90Y]DOTATOC for clinical trials: A process validation study by media fill approach

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    Aim. Radioisotopes used in nuclear radiopharmacy possess short half-lives, not allowing enough time to wait for completion of sterility tests. Moreover, carrying out sterility tests on highly radioactive solutions inside the hospital microbiology laboratory arises concerns about radioprotection. Therefore, the release of radiopharmaceuticals for injection is allowed in microbial analysis. For this reason, the effectiveness of the aseptic procedures has to be continuously assessed in order to guarantee the safety of the drug. The aim of this study was to validate the sterile preparation of [90Y]DOTATOC by means of media fill test. Methods. In order to validate the process, a simulation test was used: the media fill test. To apply this method, operators simulated each step of the process using culture medium (Triptic Soy Broth, TSB) instead of actual radiopharmaceutical product. Media fill test procedure has been subdivided into 5 phases, from the simulation of reagent preparation through the dispensing operations up to ward delivery. After every step, the processed medium was incubated at 35°C for 14 days. If the compounding procedures are adequately performed, no growth of microorganisms will be detected. Results. Microbiological analyses, carried out on all vials obtained at the end of each step, showed no microbial growth. For this reason, sterility tests were considered satisfactory. Conclusion. Application of media-fill test allowed both to validate operative modality used for [90Y]-DOTATOC handling and to attest the ability of operators who worked on it. Additionally, a correct quality control of the radiopharmaceutical i.v. preparations allows clinic infections control and prevention

    Altered Lipid Composition of Surfactant and Lung Tissue in Murine Experimental Malaria-Associated Acute Respiratory Distress Syndrome.

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    Malaria-associated acute lung injury (MA-ALI) and its more severe form malaria-associated acute respiratory distress syndrome (MA-ARDS) are common, often fatal complications of severe malaria infections. However, little is known about their pathogenesis. In this study, biochemical alterations of the lipid composition of the lungs were investigated as possible contributing factors to the severity of murine MA-ALI/ARDS. C57BL/6J mice were infected with Plasmodium berghei NK65 to induce lethal MA-ARDS, or with Plasmodium chabaudi AS, a parasite strain that does not induce lung pathology. The lipid profile of the lung tissue from mice infected with Plasmodium berghei NK65 developing MA-ALI/ARDS, but not that from mice without lung pathology or controls, was characterized by high levels of phospholipids -mainly phosphatidylcholine- and esterified cholesterol. The high levels of polyunsaturated fatty acids and the linoleic/oleic fatty acid ratio of the latter reflect the fatty acid composition of plasma cholesterol esters. In spite of the increased total polyunsaturated fatty acid pool, which augments the relative oxidability of the lung membranes, and the presence of hemozoin, a known pro-oxidant, no excess oxidative stress was detected in the lungs of Plasmodium berghei NK65 infected mice. The bronchoalveolar lavage (BAL) fluid of Plasmodium berghei NK65 infected mice was characterized by high levels of plasma proteins. The phospholipid profile of BAL large and small aggregate fractions was also different from uninfected controls, with a significant increase in the amounts of sphingomyelin and lysophosphatidylcholine and the decrease in phosphatidylglycerol. Both the increase of proteins and lysophosphatidylcholine are known to decrease the intrinsic surface activity of surfactant. Together, these data indicate that an altered lipid composition of lung tissue and BAL fluid, partially ascribed to oedema and lipoprotein infiltration, is a characteristic feature of murine MA-ALI/ARDS and possibly contribute to lung dysfunction

    HIGH PERFORMANCE LIQUID CHROMATOGRAPHIC DETERMINATION OF THALIDOMIDE IN PATIENTS AFFECTED BY HEPATOCELLULAR CARCINOMA

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    The present study developed a validate and precise reversed-phase high performance liquid chromatography (HPLC) method for the determination of thalidomide (T) in plasma, to quantify T in patients affected by hepatocellular carcinoma. Twelve male subjects aging from 62 to 82 years and weighting 66-88kg, were orally administered with single dose of T (200mg/BW). Two ml of stabilizer-solution (CH3OH/CH3CN, 1/1 (v/v)+CH3COOH 2%) were added to 1ml of human plasma and stoked to -80 degrees C until analyses. This moisture (1.38microl) was added with 20microl of CF3COOH and 100microl of phthalimide (IS) 1.75microg/ml, vortexed and centrifuged. Surnatant (800microl) was dried under vacuum at room temperature, added with 50microl of appropriate solution and injected onto HPLC. T and IS were detected at UV wavelength of 220nm with a run time of 10min. Mobile phase was 10mM pH 5.5NH4+CH3COO-/CH3CN, 75/25 (v/v) buffer at flow rate of 1.5ml/min. Inter-day and intra-day variation coefficient was <10% with an error of accuracy <10%. The present detection method was able to quantify T to every withdrawal time period (LOD 0.05microg/ml). The IS used in the present study had the same wavelength maximum absorption of T, differently from early UV detection methods reported in literature where phenacetin was used. Pharmacokinetic parameters belonging from the present study are not significantly different from those calculated in previously studies performed in human health subjects and patients affected by other pathology
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