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Biomedical subjects

E Vrachnou

Publications and source records attributed to E Vrachnou.

5 recordsLinked to original sources
PubMed2001

Lymphocyte alterations after prolonged sunlight exposure.

BACKGROUND: It has been suggested that prolonged exposure to sunlight may induce systemic or local immune alterations, which may facilitate the development of skin cancer and, perhaps, non-Hodgkin's lymphona. The effects of prolonged sunlight exposure on peripheral blood cells were studied. METHODS: Leukocytes and lymphocyte subpopulations of 12 volunteers aged 10-45 were investigated before and after a 3-week summer holiday in seaside resorts in Greece. Lymphocyte phenotypes were estimated using monoclonal antibodies and flow cytometry. RESULTS: There were no significant differences with respect to total numbers of T cells, T-helper/inducer, T-suppressor/cytotoxic, B cells or HLA-Dr+ cells. However, we have found evidence of lymphocyte stimulation, reflected in an increase in cells expressing the interleukin-2 receptor (IL-2R) and, more specifically, an increase in the T cells expressing IL-2R and HLA-Dr antigens. An increase in natural killer cells has also been noticed. CONCLUSIONS: These findings suggest that prolonged intense exposure to sunlight may be associated with immunostimulation, rather than immunosuppression.

Adolescent↗
PubMed1987

Immunological profile after splenectomy in children with beta-thalassaemia major.

The in vitro immune functions of peripheral blood lymphocytes have been studied in 12 children with beta-thalassaemia major and hypersplenism. The study was performed prior to splenectomy and on the 2nd, 6th, 15th and 30th day after splenectomy. It was found that before splenectomy, patients had low numbers of blood leucocytes, normal rosette and T3 lymphocyte counts, low T4 and normal T8 lymphocyte counts with a T4/T8 ratio below 2, impaired T lymphocyte mitogenic responses induced by PHA, increased numbers of polyvalent and monovalent B lymphocytes and normal immunoglobulin levels of IgG and IgA. After splenectomy, especially on the 2nd day, leucocytosis, a significant decrease of T cells and their subsets and a reduction of the IgM levels were found. These parameters, except the IgM levels, increased until the 30th day after splenectomy and reached presplenectomy values. On the 2nd day after splenectomy, large mononuclear cells behaving like immunocytes appeared in the peripheral blood. They had the phenotype of T3, T4, T8, B lymphocytes and OKM1 monocytes. All the large mononuclear cells increased significantly on the 6th day after splenectomy and remained elevated during the whole study (30 days). The T4/T8 ratio was increased, but no increase was found in the functional responses of T lymphocytes.

Adolescent↗
PubMed1978

The effect of passive immunization against tetanus toxoid in man.

The present study deals with the immunological response in man after passive immunization against tetanus toxoid. Treatment of man with equine antitetanus serum stimulates a rise of E rosette-forming T lymphocytes. The level of IgG also rises while the level of IgM falls. It is assumed that the foreign globulin acts as an antigen that evokes the T lymphocytes' co-operation for the humoral immune response with a switch from IgM to IgG synthesis.

Humans↗
PubMedDate not supplied

Study of apoptosis in peripheral blood of patients with acute lymphoblastic leukemia during induction therapy.

In acute lymphoblastic leukemia (ALL) the apoptosis of blast cells in peripheral blood (PB) and bone marrow before and/or during treatment, is of great interest. As the morphological changes during apoptosis provide the most reliable markers, in the present study we utilized a nuclear stain based on ethidium bromide (EtBr) for the rapid qualitative and quantitative measurement of circulating apoptotic cells directly in PB suspensions without fractionation. By using a fluorescent microscope the apoptotic cells appeared clearly visible, making the estimation of their percentage straightforward. We studied apoptosis before and during the onset of chemotherapy in PB from 16 children with ALL at diagnosis, and one upon relapse. In the cases studied at diagnosis the circulating apoptotic cells were found in variable percentages after 24 hours of treatment. Maximal apoptosis was observed after 24 hours of treatment in five cases and after 48 hours in two cases. After 96 hours of treatment the cases studied at diagnosis could be divided into three groups: those with a) negligible apoptotic cells, b) between 8% and 12% apoptotic cells and c) a high percentage of apoptotic cells (more than 20%). The relapsed case was characterized by P-glycoprotein positive blast cells, and circulating apoptotic cells which remained very low at all time points. Thus, it is possible to evaluate the response to treatment by studying apoptosis directly in peripheral blood. Therefore, the maximum apoptotic effect and the percentage of circulating apoptotic cells at the different time intervals must be considered.

ATP Binding Cassette Transporter, Subfamily B, Mem↗