Heavy metals extraction by microemulsions.

The objective of this study is the heavy metal extraction by microemulsion, using regional vegetable oils as surfactants. Firstly, the main parameters, which have influence in the microemulsion region, such as: nature of cosurfactant, influence of cosurfactant (C)/surfactant (S) ratio and salinity were studied, with the objective of choosing the best extraction system. The extraction/reextraction process by microemulsion consists of two stages. In the first one, the heavy metal ion present in the aqueous phase is extracted by the microemulsion. In a second step, the reextraction process occurs: the microemulsion phase, rich in metal, is acidified and the metal is recovered in a new aqueous phase, with higher concentration. The used system had the following parameters: surfactant-saponified coconut oil; cosurfactant-n-butanol; oil phase-kerosene; C/S ratio=4; salinity-2% (NaCl); temperature of 27+/-1 degrees C; water phase-aqueous solution that varied according to the heavy metal in study (Cr, Cu, Fe, Mn, Ni and Pb). A methodology of experimental planning was used (Scheffé Net) to study the behavior of the extraction in a chosen domain. The extraction was accomplished in one step and yielded extraction percentage higher than 98% for all metals. In the reextraction HCl-8M was used as reextraction agent and the influence of the pH and time were verified. This work showed the great efficiency of the microemulsion, indicating that it is possible to extract selectively the heavy metals from the aqueous phase.

Pediatric oncology nursing: providing care through decades of change.

Pediatric oncology nursing practice has evolved over the years as new technology and trends in health care have precipitated change. Three pediatric oncology nursing leaders share their perspectives on nursing practice as it relates to treatment of a child with leukemia during four different points in time. Their comments illustrate the challenges, resources, and rewards. Their reflections, combined with a survey of the literature over the past half a century, show the dramatic impact of advances in supportive care on the practice of caring for a child with cancer. It is also evident that as the cure rate has increased, so have the efforts to improve quality of life. What has transcended time is the delivery of consistent and compassionate care, the education of patients and families, and the dedication to advocacy and support.

Alternative donor sources in pediatric bone marrow transplantation.

Every year 2,800 children are diagnosed with leukemia and between 30% and 60% will relapse and need a bone marrow transplant. In addition, children with hematologic, genetic, or immunologic diseases may also require a transplant to be cured. Unfortunately, only 30% of these children will have a human leukocyte antigen-matched sibling donor. The current options for alternative donor sources include matched unrelated donor, mismatched related donor, and unrelated cord blood donor. Compared to a matched sibling donor, each of these options has an increased risk for graft failure and graft-versus-host disease (GVHD). For patients who receive stem cells from matched unrelated donors or mismatched related donors, the risk of graft failure is 5% to 10% and the risk of GVHD approaches 80%. After unrelated cord blood transplants, the graft failure rate is 8%, but this is potentially offset by less severe GVHD. Challenges for nurses include providing anticipatory guidance for patients and families undergoing these novel therapies and devising treatment strategies to manage the complications. Graft failure, GVHD, and infections pose the most significant risks associated with alternative donor transplants.

Steroid-refractory cutaneous graft-versus-host disease after transplantation of haploidentical parental CD34+ cells in children with Down's syndrome and recurrent acute leukemia.

PURPOSE: This study evaluated the feasibility of performing haploidentical CD34+ selected transplants for children with Down's syndrome (DS) and recurrent leukemia. PATIENTS AND METHODS: Within a cohort of 15 children, two patients had DS. Transplantation of CD34+ cells from haploidentical parents was performed after the children were conditioned with fractionated total body irradiation, cyclophosphamide, and antithymocyte globulin (ATG). Graft-versus-host disease (GVHD) prophylaxis consisted of cyclosporine and a short course of methotrexate. RESULTS: The preparative regimen was well tolerated, and engraftment of polymorphonuclear cells and platelets took place promptly (by day 20) in both patients with DS. However, both patients with DS experienced severe grade IV GVHD that was limited to the skin and was refractory to salvage with high-dose methylprednisolone therapy. In one patient, GVHD responded to second-line salvage therapy with ATG, but the patient died on day 234 from leukemic relapse. The second patient had GVHD that did not respond to ATG and died of multisystem organ failure and refractory GVHD on day 44. Two of two DS patients had steroid refractory severe acute GVHD of the skin, while only one of 11 evaluated and identically treated non-DS patients had severe GVHD (p < 0.05). CONCLUSION: These observations in patients who underwent mismatched bone marrow transplantation suggests that patients with DS have an increased risk of severe acute GVHD of the skin in this context.