Biomedical subjects

I A G Roberts

Publications and source records attributed to I A G Roberts.

5 recordsLinked to original sources

PubMed2005

Caspofungin for invasive fungal infections: combination treatment with liposomal amphotericin B in children undergoing hemopoietic stem cell transplantation.

Invasive fungal infections often prove difficult to eradicate especially in the stem cell transplant setting. Amphotericin has been the mainstay of treatment for years but has significant toxicity. Newer antifungal agents, such as caspofungin, have shown promising results in adults, particularly when used in combination with amphotericin as both drugs differ in their mode of action. However, there are few data from children and no previous published information about the use of Caspofungin after paediatric stem cell transplantation. We report our experience in children with proven invasive fungal infections after stem cell transplantation. This combination was non-toxic, and two of three patients survived their infections.

Adolescent↗

PubMed2004

Neonatal transfusion practice.

Many previously widely accepted neonatal transfusion practices are changing as neonatologists become more aware of the risks to their patients of multiple blood product transfusions. Recent literature and research on neonatal transfusion practice are here reviewed, and practical guidelines and trigger thresholds for blood products commonly used in neonatal medicine are proposed.

Albumins↗

PubMed2003

Non-TBI stem cell transplantation protocol for Fanconi anaemia using HLA-compatible sibling and unrelated donors.

Allogeneic haemopoietic stem cell transplantation (SCT) is the only curative option for severe bone marrow (BM) failure in patients with Fanconi anaemia (FA). We have developed a non total body irradiation (TBI) conditioning protocol consisting of fludarabine (120-150 mg/m(2)), low dose of cyclophosphamide (40 mg/kg) and antilymphocyte globulin (45 mg/kg). Graft-versus-host disease (GVHD) prophylaxis was with cyclosporin alone for sibling allografts but also included Campath-1 H (days 1-5 post SCT) for the unrelated allografts. We have performed two sibling and two unrelated BM transplants with a follow-up of 11-51 months. All patients experienced minimal toxicity and were discharged from hospital 28-32 days post SCT. Neutrophil and platelet engraftment occurred from days 11 to 19 and 15 to 34, respectively. All patients achieved stable full donor haemopoiesis with normalisation of the peripheral blood count despite one of them having myelodysplasia (MDS) with 8% blasts prior to the SCT. The only site of acute GVHD was in the skin (grade I-II) and only one patient progressed to limited chronic GVHD. This protocol is associated with reduced toxicity and prompt engraftment in FA patients with AA and/or MDS undergoing SCT using sibling or unrelated donors.

Adolescent↗

PubMed2003

Identification of fetal mesenchymal stem cells in maternal blood: implications for non-invasive prenatal diagnosis.

Strategies for genetic prenatal diagnosis on fetal cells in the maternal circulation have been limited by lack of a cell type present only in fetal blood. However, the recent identification of mesenchymal stem cells (MSC) in first trimester fetal blood offers the prospect of targeting MSC for non-invasive prenatal diagnosis. We developed protocols for fetal MSC enrichment from maternal blood and determined sensitivity and specificity in mixing experiments of male fetal MSC added to female blood, in dilutions from 1 in 10(5) to 10(8). We then used the optimal protocol to isolate fetal MSC from maternal blood in the first trimester, using blood taken after surgical termination of pregnancy as a model of increased feto-maternal haemorrhage. In model mixtures, we could amplify one male fetal MSC in 2.5 x 10(7) adult female nucleated cells, yielding a 100% pure population of fetal cells, but not one fetal MSC in 10(8) nucleated cells. Fetal MSC were identified in one of 20 post-termination maternal blood samples and confirmed as fetal MSC by XY fluorescence in-situ hybridization (FISH), immunophenotyping and osteogenic and adipogenic differentiation. We report the isolation of fetal MSC from maternal blood; however, their rarity in post-termination blood suggests they are unlikely to have a role in non-invasive prenatal diagnosis. Failure to locate these cells routinely may be attributed to their low frequency in maternal blood, to sensitivity limitations of enrichment technology, and/or to their engraftment in maternal tissues soon after transplacental passage. We speculate that gender microchimerism in post-reproductive maternal tissues might result from feto-maternal trafficking of MSC in early pregnancy.

Adult↗

PubMed2002

Platelet transfusion in the management of severe thrombocytopenia in neonatal intensive care unit patients.

Platelet transfusions are frequently given to neonatal intensive care unit (NICU) patients with severe thrombocytopenia (platelets less than 50 x 10(9) L(-1)) but no study has assessed whether this is clinically appropriate. To address this we conducted a retrospective review of platelet transfusion practice in patients developing severe thrombocytopenia over 3 years in a single NICU. Out of 901 admissions, 53 (6%) developed severe thrombocytopenia. Twenty-seven neonates received a total of 63 platelet transfusions, the main triggers being: platelet count less than 30 x 10(9) L(-1) (all patients), or less than 50 x 10(9) L(-1) in those with previous haemorrhage or clinical instability. No major haemorrhage occurred during severe thrombocytopenia either in neonates in whom platelet transfusions were withheld (26/53) or in neonates given platelets who survived to discharge (22/27). Five preterm neonates given platelets died but all had overwhelming sepsis or necrotizing enterocolitis and none died directly as a result of haemorrhage. Although the widely used liberal triggers for neonatal platelet transfusion highlighted in this review reflect available guidelines, and represent cautious ('safe') haemostatic practice, they are likely to result in unnecessary transfusion for a significant number of NICU patients. Improved practice requires definition of a safe lower limit for platelet count in stable neonates; effective platelet transfusion strategies for sick neonates; and improved therapies for conditions precipitating severe thrombocytopenia.

Disease Management↗