Biomedical subjects

Jesus Lopez-Fidalgo

Publications and source records attributed to Jesus Lopez-Fidalgo.

4 recordsLinked to original sources

PubMed2005

Long-term immune recovery of patients undergoing allogeneic stem cell transplantation: a comparison with their respective sibling donors.

We have addressed whether patients' immune system status after allogeneic stem cell transplantation, assessed more than 1 year after the procedure, recovers normal function as compared with that of their respective donors. An additional aim was to compare the status of the immune system between patients receiving reduced-intensity conditioning regimens and those undergoing myeloablative transplantations. For this purpose, we analyzed not only the different subsets of peripheral blood (PB) lymphocytes, but also circulating dendritic cell (DC) subpopulations, together with cytokine production by PB T cells, in a series of 38 patients undergoing allogeneic stem cell transplantation. We compared these patients with their respective HLA-matched donors by performing a simultaneous patient/donor paired study. Complete bone marrow chimerism status and normal PB cell counts were demonstrated in all recipients. The most relevant numeric differences found between patients and donors were related to the distribution of the distinct subsets of PB DCs (CD16+ DCs were increased, whereas myeloid and plasmacytoid DC subsets were decreased in the patient group). This was associated with an increased number of B cells, an inverted CD4/CD8 T-cell ratio, and a decrease in CD4+/CD8+ double-positive T cells in the patient group. In addition, a predominance of a T-helper 1 pattern of cytokine production (interferon gamma and tumor necrosis factor alpha) with decreased secretion of T-helper 2-associated cytokines (interleukin 5 and interleukin 10) was also observed at the single-cell level. No significant differences were found in any of the parameters analyzed between patients receiving reduced-intensity conditioning regimens and those undergoing myeloablative transplantations.

Adolescent↗

PubMed2005

Posttransplant hematopoiesis in patients undergoing sibling allogeneic stem cell transplantation reflects that of their respective donors although with a lower functional capability.

We tested the principle of whether patient long-term hematopoiesis following allogeneic stem cell transplantation (allo-SCT) reflects the characteristics of the hematopoiesis of their respective donor. For this purpose, we analyzed bone marrow (BM) hematopoiesis using long-term cultures (LTC), delta assays, and clonogeneic assays as well as CD34+ cells and their subsets by flow cytometry in a series of 37 patients undergoing allo-SCT, and we compared it to that of their respective human leukocyte antigen-matched sibling donors in a paired study performed more than 1 year after the transplant procedure. Interestingly, the main factor that influenced post-allo-SCT BM hematopoiesis in the long term was donor hematopoiesis. Nevertheless, compared to their respective donors, patients exhibited a significantly lower number of colony-forming units granulomonocytic, burst-forming units erythroid, and immature progenitors (CD34++/CD38dim/CD90+/CD133+ cells, LTC-initiating cells, and colonies generated in the delta assay). Moreover, BM stromal function was diminished in patients undergoing allo-SCT compared to their donors. In addition, the presence of chronic graft-versus-host disease under immunosuppressive treatment also conditioned an impaired hematopoietic function. In summary, our study shows that BM hematopoiesis evaluated more than 1 year after an allo-SCT mainly reproduces that of their respective donors, although with a significantly decreased in vitro activity.

Adolescent↗

PubMed2005

Statistical criteria to establish bioassay programs.

A statistical study of fitting log-normal distributions to air sampling concentrations and random intakes is reported in this paper. An improved method on the approximation of a sum of log-normal distributions to a log-normal distribution is used to forecast bioassay results and their uncertainties. These methods can be used in the design and implementation of air control monitoring and bioassay programs for introducing statistical criteria to determine when a bioassay is required as well as the frequency.

Air Pollutants, Radioactive↗

PubMed2003

Mathematical techniques for solving analytically large compartmental systems.

The flow of radioactive particles inside the body from internally deposited radioisotopes in people exposed to inhalation, ingestion, injection, or other ways is usually evaluated using compartmental models. The biokinetic models included in the documents of the International Commission on Radiological Protection such as International Commission on Radiological Protection 66 and 78 involve many compartments. Usually numeric methods are applied. Very often analytical solutions are not possible. New computer programs that include symbolic capability can be used to solve compartmental systems. In this paper some techniques are developed in order to make feasible a computer program that gives not only faster and more accurate solutions, but also analytic solutions for these kind of models. The main idea is to make a partition of subsystems and solve them sequentially. The concept of pseudotrap compartments in a subsystem is crucial at this point. Impulse (acute), constant, and continuous (such as exponential) intakes are considered. This technique has been applied to develop a computer code called Humorap to solve the International Commission on Radiological Protection 66 and 78 models.

Air Pollutants↗