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Biomedical subjects

G Andreu

Publications and source records attributed to G Andreu.

At least 73 records · Page 4Linked to original sources
PubMed1988

Prevention of HLA immunization with leukocyte-poor packed red cells and platelet concentrates obtained by filtration.

HLA immunization is a common complication of transfusion therapy in 30% to 60% of oncohematologic patients. Evidence shows that leukocytes present in cellular blood products are the main component involved in the occurrence of HLA immunization, and several studies showed that leukocyte-poor blood products are less able to induce it. However, leukocyte-poor platelet concentrates obtained by conventional techniques, ie, centrifugation, frequently have a high level of remaining leukocytes. Cotton wool filter Imugard IG 500 can be used to obtain leukocyte-poor cellular blood products. The technique is easy to perform, even in an emergency, and can be used with either packed RBCs or platelet concentrates. Means of 97%, 92%, and 76% elimination of leukocytes are obtained for packed RBCs, pooled standard platelet concentrates, and single-donor platelet concentrates, respectively. Patients were randomized to receive either standard (control group) or filtered (leukocyte-poor group) blood products. Of 112 randomized patients, 69 were evaluable, 35 in the control group and 34 in the leukocyte-poor group. Both groups are comparable according to age, diagnosis, sex ratio, previous transfusions, and pregnancies. There is a significant difference in regard to the HLA immunization rate (31.4% in the control v 11.7% in the leukocyte-poor group, P less than .05) and frequency of refractoriness to platelet transfusions (46.6% v 11.7%, P less than .05). We conclude that this filtration technique can be an efficient means to reduce the HLA immunization rate in polytransfused oncohematologic patients.

Adolescent↗
PubMed1987

Prevention of graft-versus-host disease in HLA-matched bone marrow transplantation for malignant diseases: a multicentric study of 62 patients using 3-pan-T monoclonal antibodies and rabbit complement.

In order to evaluate the effectiveness and reproducibility of T cell depletion in human leukocyte antigen (HLA)-matched bone marrow graft to prevent graft-v-host disease (GVHD), our multicentric study (nine different centers) investigated 62 consecutive patients with poor prognosis leukemia or hematosarcoma from June 1984 to November 1985. The data were updated October 1, 1986, and the mean follow-up was 18 +/- 4.3 months. T cells were depleted with a combination of 3-pan-T cell monoclonal antibodies (CD2 "D66"; CD5 "A50"; CD7 "I21") with a single incubation of rabbit complement (C'). The average number of T cells infused was 0.66 X 10(6) +/- 0.56/kg body weight. Twenty-six patients received chemoprophylaxis for GVHD, 16 received methotrexate, and ten received cyclosporin A. Only a single case of severe (greater than grade II) GVHD was observed, yet the incidence of graft failure was 19%. Factors that might have influenced the occurrence of graft failure appear to be the lack of radiotherapy in the conditioning regimen; the conditioning regimen itself (fractionated total body irradiation [TBI], 12 Gy, v single dose is better than TBI, 10 Gy, but still not statistically significant); and the age of the patients (high-risk after 30 years of age). In contrast, neither the number of nucleated cells reinfused nor the level of T cell depletion (provided the T cells were below critical numbers) seemed to have an influence, nor did chemoprophylaxis for GVHD or splenectomy in chronic granulocytic leukemia (CGL) patients. The survival of graft failure patients was very poor (one of 11; survival at 15 months of the initial graft). Thus, our study demonstrates the reproducibility and high effectiveness in preventing GVHD by immunodepletion of T cells in a large-scale multicentric assay, in which compliance with the protocol of immunodepletion was reasonably good. This study thus provides interesting clues to overcoming graft rejection.

Adolescent↗
PubMed1987

T-cell depletion does not affect long-term human bone marrow culture.

Bone marrow long-term cultures were studied for 8 weeks in four experiments before and after T-cell depletion with a mixture of monoclonal antibodies directed against CD2, CD5 and CD7. No differences in cellularity or granulomonocytic progenitor numbers appeared during the period of culture. We conclude that in vitro treatment in itself is not likely to explain non-take or graft rejection associated with T-depleted bone marrow transplantation.

Animals↗
PubMed1986

Thrombocytopenia in venocclusive disease after bone marrow transplantation or chemotherapy.

Hepatic venocclusive disease (VOD) is a frequent complication of bone marrow transplantation (BMT). Analysis of 13 cases observed during a 3-year period in our BMT center shows that VOD is associated with a constant peripheral thrombocytopenia and refractoriness to platelet transfusion. These signs appear in the very early stage of VOD, five to ten days before the classical signs, painful hepatomegaly and sudden weight gain. Analysis of platelet consumption, frequency of platelet transfusion and platelet recovery, and examination of known causes of peripheral thrombocytopenia (mainly allo- and autoimmunization, disseminated intravascular coagulation [DIC] and splenomegaly) lead to the conclusions that this association is not coincidental. The exact mechanism of platelet consumption in VOD is unknown.

Bone Marrow Transplantation↗
PubMed1986

[Expansion of erythropoiesis and granulopoiesis after bone marrow grafts].

Erythropoietic and granulopoietic expansion after bone marrow transplantation (BMT) are reviewed in 60 allogeneic and autologous BMT. Morphological dyserythropoiesis was more prominent than dysgranulopoiesis. Dyserythropoiesis was present with increased HbF synthesis and i antigen expression. We did not find nocturnal paroxysmal hemoglobinuria and leukocytic alkaline phosphatase level was high. CFU-GM progenitors were still reduced in number 1 year after BMT. The clusters/colonies ratio, increased at day 12 after BMT was normal by day 100. No difference between autologous and allogeneic BMT was observed.

Anemia, Aplastic↗
PubMed1984

Studies on purification of human gamma interferon: chromatographic behavior of accompanying IL2 and B-cell helper activity.

Gamma interferon (gamma IFN) was produced in human lymphocyte cultures stimulated by PHA. Titers were in the range of 10,000-30,000 U/ml. Crude gamma IFN was adsorbed on silicic acid, from which the antiviral activity was eluted by a buffer containing a high salt concentration and ethylene glycol. This treatment allowed quantitative recovery of gamma IFN with a specific activity of 5 X 10(5)-1 X 10(6) U/mg of proteins. IL2 and B-cell helper activities were adsorbed and eluted from silicic acid together with the antiviral activity. This finding might be of practical interest for the purification of these lymphokines, particularly IL2. Gamma interferon was further purified on Blue Sepharose to a specific activity of 2 X 10(7) U/mg. The resulting preparations still contained IL2 and B cell helper activities. However, taking advantage of the differences in apparent hydrophobicity and in isoelectric point, we were able to dissociate antiviral activity from lymphokines. Such dissociation should facilitate the study of the biological properties of human natural gamma IFN.

Adsorption↗
PubMed1984

[Therapeutic leukapheresis in tricholeukocytic leukemia].

Therapeutic leukapheresis was performed in a patient with hairy cell leukaemia (100,000 WBC/mm3; 98 p. 100 hairy cells) without signs of hypersplenism. Twenty-five sessions were carried out in 12 weeks. A rapid and significant improvement was observed with the WBC falling to 25,000 WBC/mm3 with 70 p. 100 of hairy cells and the normalisation of the bone marrow biopsy. When these sessions were finished, splenectomy was performed in optimal conditions. This treatment would seem to be valuable in hairy cell leukaemia without severe hypersplenism. Long-term improvement may be hoped because hairy cells have a very short turnover rate.

Adult↗
PubMed1983

Treatment of progressive systemic sclerosis with plasma exchange. Seven cases.

Seven patients, 4 women and 3 men afflicted with severe progressive systemic sclerosis (PSS) were treated with Plasma Exchange after failure of different other treatment. All patients presented Raynaud phenomenon and arthritis, 6 patients presented extensive skin lesions, 5 of them digestive manifestations, 3 pulmonary fibrosis. In one case PSS was associated with polymyositis, one patient presented bilateral recurrent cornea ulcerations, (Sjögren Syndrome++) and one patient numerous skin ulcerations. In 5 patients adjuvant corticosteroid therapy was given during the course of PE. In 3 patients PE must be stopped after one or two sessions because of insufficient venous access. Among the 4 other patients 8 to 20 PE were performed: the patient with cornea ulcerations became blind during the treatment, skin ulcerations and severe Raynaud phenomenon did not improved in two other patients. Benefit of PE was noted in only one patient with regressive myositis, and improvement of articular and cutaneous symptoms. Therefore, PE are not useful in most patients afflicted with PSS, they are difficult to realize in numerous patients and did not improve clinical symptoms in most cases.

Adolescent↗
PubMed1982

Translation of mRNA from phytohemagglutinin-stimulated human lymphocytes: characterization of interferon mRNAs.

Human lymphocytes obtained by cytapheresis were stimulated in spinner culture conditions by nonpurified PHA in order to study the production of gamma interferon, and the characterization of IFN-gamma mRNA. Titers of interferon prepared in 0.6 to 4 1 batches, varied in 20 preparations from 8,000 to 32,000 units/ml. This interferon was unstable at pH 2: the residual antiviral activity after 20 h treatment was less than 3%. Antibodies raised against gamma interferon from Con A and SEA-stimulated lymphocytes neutralized the interferon induced by PHA, indicating that all three preparations are antigenically related. Poly(A)RNA from control, noncultivated lymphocytes and from lymphocytes stimulated by PHA for 18 h were translated in reticulocyte lysates and analysed by polyacrylamide gel electrophoresis. The pattern of synthesized polypeptides was different suggesting modifications in the population of mRNA. When total poly(A)RNA was inoculated into Xenopus Laevis oocytes, interferon activity was found with both, control and stimulated mRNAs although only at low levels in the control. After sucrose gradient fractionation of poly(A)RNA, each fraction was inoculated into oocytes and interferon activity measured in the oocyte bathing medium. A low level was synthesized by the RNA fractions around 28 S from control as well as from stimulated lymphocytes. These interferons were not neutralized by anti-IFN-alpha or anti-IFN-gamma sera but they were neutralized by anti-IFN-beta serum. Only the 16 S RNA fraction from PHA-stimulated lymphocytes induced high levels of interferon in oocytes. This interferon has been characterized as gamma interferon. Each fraction obtained from sucrose gradients on poly(A)RNA from control and PHA-stimulated lymphocytes was translated in reticulocyte lysate. Gel analysis of the products showed striking differences when the same fraction of both RNAs were compared. Concerning particularly the 16 S RNA from PHA-stimulated lymphocytes, where gamma interferon mRNA was present, polypeptides ranged from 15 to 55 K with a bulk around 45 K, indicating heterogeneous RNA molecules.

Animals↗
PubMed1980

Tk polyagglutination produced in vitro by an endo-beta-galactosidase.

After treatment with the culture supernatant of Bacteroides fragilis or with an endo-beta-galactosidase from Escherichia freundii, the human red blood cells are Tk-activated, i.e. agglutinable by BS II lectin and their blood group I and i activities are reduced. These results suggest that B. fragilis produces an endo-beta-galactosidase activity and that the main antigenic determinant of Tk polyagglutinable red cells is a terminal N-acetyl-glucosamine residue.

Agglutination↗
PubMed1979

[Association of acquired polyagglutinabilities of types T and B. An observation].

Although T and acquired B polyagglutinabilities are not exceptional, simultaneous occurence of the two types is a rarer phenomenon. Ten days after an open heart surgery operation, the patient, age 55, had an infectious syndrom : two strains, Clostridium perfringens and Peptococcus variabilis were isolated. Simultaneously, her red cells were found to be polyagglutinable. The association of T and acquired B polyagglutinabilities could be demonstrated by serological studies of the patient's red cells, and by in vitro transformation of normal red cells using culture supernatants obtained from the two isolated strains.

ABO Blood-Group System↗
PubMed1979

Induction of Tk polyagglutination by Bacteroides fragilis culture supernatants. Associated modifications of A B H and I i antigens.

Tk transformed red blood cells were obtained in vitro by treatment with supernatants from cultures of three different Bacteroides fragilis strains. The reactions of these cells with AB sera show that Tk is different from other known types of polyagglutination. Beside the already known modifications of A B H antigens, we found that Tk activated cells have an important modification of I and i antigens: both are reduced, and can even be completely destroyed.

ABO Blood-Group System↗