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Antenatal steroids like dexamethasone (DEX) are used to augment foetal lung maturity and there is a major concern that they impair foetal growth. If delivery is delayed after using antenatal DEX, placental function and hence foetal growth may be compromised even further. To investigate the effects of DEX on placental function, we treated 9 pregnant C57/BL6 mice with DEX and 9 pregnant mice were injected with saline to serve as controls. Placental gene expression was studied using microarrays in 3 pairs and other 6 pairs were used to confirm microarray results by semi-quantitative RT-PCR, real-time PCR, in situ hybridization, western blot analysis and Oligo ApopTaq assay. DEXtreated placentas were hydropic, friable, pale, and weighed less (80.0±15.1 mg compared to 85.6.8 ±7.6 mg, p=0.05) (n=62 placentas). Foetal weight was significantly reduced after DEX use (940±32 mg compared to 1162±79 mg, p=0.001) (n=62 foetuses). There was > 99% similarity within and between the three gene chip data sets. DEX led to down-regulation of 1212 genes and up-regulation of 1382 genes. RT-PCR studies showed that DEX caused a decrease in expression of genes involved in cell division such as cyclins A2, B1, D2, cdk 2, cdk 4 and M-phase protein kinase along with growth-promoting genes such as EGF-R, BMP4 and IGFBP3. Oligo ApopTaq assay and western blot studies showed that DEX-treatment increased apoptosis of trophoblast cells. DEX-treatment led to up-regulation of aquaporin 5 and tryptophan hydroxylase genes as confirmed by real-time PCR, and in situ hybridization studies. Thus antenatal DEX treatment led to a reduction in placental and foetal weight, and this effect was associated with a decreased expression of several growth-promoting genes and increased apoptosis of trophoblast cells.

In a cohort of children with sickle cell disease (SCD) and vaso-occlusive pain visits served through South Carolina's Medicaid system over a 6-year period (N 5 523), we compared the number of vaso-occlusive pain or acute chest syndrome (ACS)/pneumonia episodes, and outpatient or acute service costs in those treated or not treated with hydroxyurea (HU). HU may be an underused intervention for SCD in this practice setting, for a variety of reasons. Treatment with HU varied greatly, appears to have been administered to more severely ill children, but was associated with a reduction in vaso-occlusive pain episodes, hospitalizations, and total costs of care within the HU cohort during a 2-3 year period of active HU treatment. Those receiving care through specialized SCD clinics were less likely to have pain or acute care episodes (RR 5 0.79, P < 0.0001; RR 5 0.90, P 5 0.01). Compared with the non-HU cohort, the HU group evinced a significantly higher risk of experiencing vaso-occlusive pain episodes (RR 5 3.32, P < 0.0001) and ACS/pneumonia episodes (RR 5 2.66, P < 0.0001), and higher outpatient, inpatient/emergency, and total service costs (RR 5 1.85, 2.11, 2.10, and P < 0.0001, respectively) over time. HU is clinically effective in reducing pain episodes, hospitalizations, and total care costs, but those receiving it might be more severely ill.Erythrocytes in children with sickle cell disease (SCD) become deoxygenated, dehydrated, and crescent-shaped, and tend to aggregate or stick to blood vessel walls, blocking blood flow within limbs and organs, causing painful episodes. These patients are frequently seen in emergency departments and hospitalized for these severe pain episodes [1]. SCD poses an enormous personal burden to these young patients and is also costly to the family and third-party payer, especially for low-income children [2]. Interventions designed to control vaso-occlusive pain episodes, and avoid hospitalizations may reduce the significant personal and economic burdens of the disease [3,4].Hydroxyurea (HU), a myelosuppressive agent, which raises the levels of Hb F [5] and of hemoglobin [6][7][8], effectively decreases the rate of painful vaso-occlusive and acute chest syndrome (ACS) episodes by 50% in adults [9][10][11][12], and is generally safe and well-tolerated in children older than 5 years of age [13]. There is strong evidence that HU reduces the frequency of hospitalization in children with SCD and moderate evidence that it decreases the frequency of painful crises [14]. Given the short-term safety profile of HU in children and its established efficacy in adults, HU is commonly used, off-label, in children with multiple painful episodes (3 per year) to reduce episode frequency and acute services utilization [15][16][17], even in children as young as 9 months.Results from a multicenter study of HU in sickle-cell anemia demonstrated that adult patients treated with HU had a 44% decrease in hospitalizations compared with those taking placebo, which accounted for the majority of cost savings in ...

We previously demonstrated that inhaling nitric oxide (NO) increases the oxygen affinity of sickle red blood cells (RBCs) in patients with sickle cell disease (SCD). Our recent studies found that NO lowered the P50 values of sickle hemoglobin (HbS) hemolysates but did not increase methemoglobin (metHb) levels, supporting the role of NO, but not metHb, in the oxygen affinity of HbS. Here we examine the mechanism by which NO increases HbS oxygen affinity. Because anti-sickling agents increase sickle RBC oxygen affinity, we first determined whether NO exhibits anti-sickling properties. The viscosity of HbS hemolysates, measured by falling ball assays, increased upon deoxygenation; NO treatment reduced the increment. Multiphoton microscopic analyses showed smaller HbS polymers in deoxygenated sickle RBCs and HbS hemolysates exposed to NO. These results suggest that NO inhibits HbS polymer formation and has anti-sickling properties. Furthermore, we found that HbS treated with NO exhibits an isoelectric point similar to that of HbA, suggesting that NO alters the electric charge of HbS. NO–HbS adducts had the same elution time as HbA upon high performance liquid chromatography analysis. This study demonstrates that NO may disrupt HbS polymers by abolishing the excess positive charge of HbS, resulting in increased oxygen affinity.

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The DNA microarray results support the idea that T cells and immunomodulatory factors (cytokines, chemokines) are likely to be involved in HSV-1 retinitis. These results also suggest that B cells and/or macrophages play a role in the pathogenesis of HSV-1 retinitis.

Abstract-Deoxyribonucleic acid (DNA) microarrays provide a means to assess genome-wide expression patterns after exposure of an organism to different xenobiotics. Potential uses for this technology include identification of unknown toxicants, assessment of toxicity of new compounds, and characterization of the cellular mechanisms of toxicant action. Here we describe another use of DNA microarrays in toxicant-specific gene discovery. Combining results from two DNA microarray experiments, we have identified genes from the model plant Arabidopsis thaliana that are induced in response to one but not other heavy metals. The promoters of these genes should be useful in developing metal-specific transgenic biomonitors. To test this idea, we have fused the promoter of one of the newly identified Ni-inducible genes (AHB1) to the ␤-glucuronidase (GUS) reporter gene. Arabidopsis plants containing the AHB1::GUS transgene show reporter gene activity when they are grown on media containing Ni but not when grown on media containing Cd, Cu, Zn, or without added metals. Thus, this approach has resulted in the creation of a transgenic strain of Arabidopsis that can report on the presence and concentration of Ni in plant growth media. Such transgenic models can serve as cheap and efficient biomonitors of bioavailable heavy metal contamination in soils and sediments.

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