Severe Vaso-Occlusive Episodes Associated with Use of Systemic Corticosteroids in Patients with Sickle Cell Disease.

Patients with sickle cell disease (SCD) are occasionally prescribed systemic corticosteroids to treat steroid-responsive conditions. Additionally, use of systemic corticosteroids for sickle cell pain episodes and acute chest syndrome is under investigation. We report 4 patients with SCD who developed severe vaso-occlusive events following the administration of systemic steroids. We also review similar cases from the literature and suggest measures for reducing the potential risk associated with use of systemic corticosteroids in this group of patients. We conclude that corticosteroids should be used with caution in patients with SCD.

Cytomegalovirus infections in allogeneic stem cell recipients after reduced-intensity or myeloablative conditioning assessed by quantitative PCR and pp65-antigenemia.

Since the incidence of cytomegalovirus (CMV) infections after hematopoietic stem cell transplantation (HSCT) may depend on the intensity of the pretreatment, we studied the incidence of CMV infections after reduced-intensity compared to myeloablative conditioning. A total of 82 patients with matched related or unrelated donors were prospectively monitored for CMV infections after HSCT by CMV-PCR techniques, CMV-antigenemia and clinical observation. A total of 45 patients received reduced-intensity conditioning consisting of fludarabine, busulfan and ATG and 37 patients received myeloablative conditioning. Leukocyte engraftment occurred after a median of 15 vs 18 days (P=0.012) and platelet engraftment after 12 days vs 20 days (P=0.001), respectively. Acute graft-versus-host disease (GVHD) grade II-IV was observed in 58 vs 54% patients (P=0.737), respectively. The onset and peak values of CMV-antigenemia and DNAemia and the incidence of CMV infections did not differ statistically significantly between the two treatment groups. Multivariate analysis confirmed CMV seropositivity of the recipient (P=0.035), acute GVHD II-IV (P=0.001) but not the type of conditioning as significant risk factors for CMV-antigenemia. In conclusion, the kinetics of CMV-antigenemia and DNAemia and the incidence of CMV infections were not statistically different in patients who received HSCT after reduced-intensity conditioning with fludarabine, busulfan and ATG compared to myeloablative conditioning.

Plastid redox state and sugars: interactive regulators of nuclear-encoded photosynthetic gene expression.

Feedback regulation of photosynthesis by carbon metabolites has long been recognized, but the underlying cellular mechanisms that control this process remain unclear. By using an Arabidopsis cell culture, we show that a block in photosynthetic electron flux prevents the increase in transcript levels of chlorophyll a/b-binding protein and the small subunit of Rubisco that typically occurs when intracellular sugar levels are depleted. In contrast, the expression of the nitrate reductase gene, which is induced by sugars, is not affected. These findings were confirmed in planta by using Arabidopsis carrying the firefly luciferase reporter gene fused to the plastocyanin and chlorophyll a/b-binding protein 2 gene promoters. Transcription from both promoters increases on carbohydrate depletion. Blocking photosynthetic electron transport with 3-(3', 4'-dichlorophenyl)-1,1'-dimethylurea prevents this increase in transcription. We conclude that plastid-derived redox signaling can override the sugar-regulated expression of nuclear-encoded photosynthetic genes. In the sugar-response mutant, sucrose uncoupled 6 (sun6), plastocyanin-firefly luciferase transcription actually increases in response to exogenous sucrose rather than decreasing as in the wild type. Interestingly, plastid-derived redox signals do not influence this defective pattern of sugar-regulated gene expression in the sun6 mutant. A model, which invokes a positive inducer originating from the photosynthetic electron transport chain, is proposed to explain the nature of the plastid-derived signal.

Tissue artefacts caused by sponge in embedding cassettes.

Sponges in embedding cassettes may cause disruptive imprints on the tissues being processed and therefore should not be used in processing tissues. Tissue or lens paper is recommended as a substitute to prevent losing small pieces of tissue through the perforations of the cassette.