Browsing by Author "PORTO, B."
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- Growth hormone (GH)‐induced reconstitution of CD8+ CD28+ T lymphocytes in a rare case of severe lymphopenia associated with Juvenile Haemochromatosis and Turner's syndrome.Publication . PORTO, G.; CRUZ, E.; MIRANDA, H.; PORTO, B.; VASCONCELOS, J.; LACERDA, R.; ROETTO, A.; DARAIO, F.; BACELAR, C.Clin Endocrinol (Oxf). 2004 Oct;61(4):437-40. Growth hormone (GH)-induced reconstitution of CD8+ CD28+ T lymphocytes in a rare case of severe lymphopenia associated with Juvenile Haemochromatosis and Turner's syndrome. Porto G, Cruz E, Miranda HP, Porto B, Vasconcelos JC, Lacerda R, Roetto A, Daraio F, Bacelar C. Santo António General Hospital, Porto, Portugal. gporto@ibmc.up.pt Abstract This paper describes a rare case of Turner's syndrome associated with Juvenile Haemochromatosis and severe lymphopenia, followed-up for a period of 5 years. Because of the indication for treatment with growth hormone (GH), this case was observed as a model to analyse the effects of GH on growth, iron mobilization and lymphocyte reconstitution. For this purpose, a serial study of the T lymphocyte subpopulations CD4+, CD8+, CD8+ CD28+ and CD8+ CD28- was performed by immunophenotyping during the follow-up period. Besides the impact of both phlebotomy treatment and GH on the rapid growth and mobilization of 20.8 g of iron in 136 weeks, the most relevant observation was the finding of a significant expansion of CD8+ T lymphocytes expressing the costimulatory marker CD28 in the setting of the severe lymphopenia. These findings constitute new clinical evidence supporting the notion that the GH/IGF-1 system has an important role on the maintenance of T cell homeostasis in vivo, and that GH may be regarded as a putative therapeutic agent in T lymphocyte reconstitution. PMID: 15473875 [PubMed - indexed for MEDLINE]
- Human red blood cells have an enhancing effect on the relative expansion of CD8+ T lymphocytes in vitroPublication . PORTO, B.; FONSECA, A.M.; GODINHO, I.; AROSA, F.A.; PORTO, G.Cell Prolif. 2001 Dec;34(6):359-67. Human red blood cells have an enhancing effect on the relative expansion of CD8+ T lymphocytes in vitro. Porto B, Fonseca AM, Godinho I, Arosa FA, Porto G. Laboratory of Cytogenetics, Abel Salazar Institute for the Biomedical Sciences (ICBAS), Porto, Portugal. malheiro@icbas.up.pt Abstract The present study was designed to analyse the effect of red blood cells on T-cell proliferation and expansion. A comparative study was done in peripheral blood cell cultures stimulated with phytohemagglutinin, with or without red blood cells. The presence of red blood cells had a consistent enhancing effect on T lymphocyte proliferation, as determined by an increase in both the mitotic index and thymidine uptake. Phenotypic characterization of T cell blasts by flow cytometry revealed that, in the presence of red blood cells, expanding cells were preferentially CD8+ cells. Accordingly, proliferation of CD8+ lymphocytes from two patients with CD8+ hyperlymphocytosis was dependent on the presence of red blood cells. In contrast, proliferation of CD4+ lymphocytes from two patients with CD4+ hyperlymphocytosis was strongly inhibited by the presence of red blood cells. This is the first reported evidence that human red blood cells have an enhancing effect on the expansion of CD8+ lymphocytes in vitro. PMID: 11737000 [PubMed - indexed for MEDLINE]
- Role of haemoglobin in the protection of cultured lymphocytes against diepoxybutane (DEB), assessed by in vitro induced chromosome breakage.Publication . PORTO, B.; CHIECCHIO, L.; GASPAR, J.; FABER, A.; PINHO, L.; RUEFF, J.; MALHEIRO, I.Mutat Res. 2003 Apr 20;536(1-2):61-7. Role of haemoglobin in the protection of cultured lymphocytes against diepoxybutane (DEB), assessed by in vitro induced chromosome breakage. Porto B, Chiecchio L, Gaspar J, Faber A, Pinho L, Rueff J, Malheiro I. Laboratory of Cytogenetics, Instituto Ciências Biomédicas Abel Salazar (ICBAS), Largo do Prof. Abel Salazar, No. 2, 4099-003, Porto, Portugal. Abstract Diepoxybutane (DEB) is an alkylating agent that can be used to assess chromosome instability in repair-deficient subjects. Previous authors investigated the role of red blood cells (RBC) in determining individual susceptibility to DEB in normal healthy donors, and demonstrated that a polymorphic enzyme in RBC, Glutathione S-transferase T1 (GSTT1), is involved in DEB detoxification. In the present work we studied the influence of individual GSTM1 and GSTT1 genotypes and the presence of RBC on the frequency of DEB-induced chromosome breakage in lymphocyte cultures from normal individuals and, in particular, the influence of isolated components of RBC: RBC membranes, RBC lysate, and haemoglobin. Our results confirm that individual GSTT1 genotypes modulate the level of genetic lesions induced by DEB; however, this effect was not sufficient to explain the highly significant variation in chromosome breakage between whole blood and RBC-depleted cultures. We showed that RBC can protect cultured lymphocytes against chromosome breakage induced by DEB and we demonstrated the particular role of haemoglobin in the protective effect. PMID: 12694746 [PubMed - indexed for MEDLINE]