[Hypophosphatemia in critically ill patients]

Phosphorus is a mineral element essential to cellular function. The prevalence of hypophosphatemia is particularly high in critically ill patients. Hypophosphatemia may be the result of increased renal excretion, reduced digestive absorption, intracellular shift accompanied or not by depletion of the total phosphorus pool, and extreme catabolic states. Clinical manifestations are especially apparent in severe hypophosphatemia and include impairments of the respiratory, musculo-skeletal, pulmonary, and neurological systems. Hypophosphatemia must be corrected, especially if it is severe and symptomatic.

HDAC inhibitors potentiate the activity of the BCR/ABL kinase inhibitor KW-2449 in imatinib-sensitive or -resistant BCR/ABL+ leukemia cells in vitro and in vivo

PURPOSE

The purpose of this study was to determine whether histone deacetylase (HDAC) inhibitors (HDACI) such as vorinostat or entinostat (SNDX-275) could increase the lethality of the dual Bcr/Abl-Aurora kinase inhibitor KW-2449 in various Bcr/Abl(+) human leukemia cells, including those resistant to imatinib mesylate (IM).

EXPERIMENTAL DESIGN

Bcr/Abl(+) chronic myelogenous leukemia (CML) and acute lymphoblastic leukemia (ALL) cells, including those resistant to IM (T315I, E255K), were exposed to KW-2449 in the presence or absence of vorinostat or SNDX-275, after which apoptosis and effects on signaling pathways were examined. In vivo studies combining HDACIs and KW2449 were carried out by using a systemic IM-resistant ALL xenograft model.

RESULTS

Coadministration of HDACIs synergistically increased KW-2449 lethality in vitro in multiple CML and Ph(+) ALL cell types including human IM resistant cells (e.g., BV-173/E255K and Adult/T315I). Combined treatment resulted in inactivation of Bcr/Abl and downstream targets (e.g., STAT5 and CRKL), as well as increased reactive oxygen species (ROS) generation and DNA damage (γH2A.X). The latter events and cell death were significantly attenuated by free radical scavengers (TBAP). Increased lethality was also observed in primary CD34(+) cells from patients with CML, but not in normal CD34(+) cells. Finally, minimally active vorinostat or SNDX275 doses markedly increased KW2449 antitumor effects and significantly prolonged the survival of murine xenografts bearing IM-resistant ALL cells (BV173/E255K).

CONCLUSIONS

HDACIs increase KW-2449 lethality in Bcr/Abl(+) cells in association with inhibition of Bcr/Abl, generation of ROS, and induction of DNA damage. This strategy preferentially targets primary Bcr/Abl(+) hematopoietic cells and exhibits enhanced in vivo activity. Combining KW-2449 with HDACIs warrants attention in IM-resistant Bcr/Abl(+) leukemias.

Nanocharacterization of Surface and Interface of Different Epoxy Networks

The effect of network changes on the surface and interface properties of amine-cured epoxy has been investigated. Samples of different crosslinked epoxies are prepared by mixing stoichiometrically pure diglycidyl ether of bisphenol A (n=0.03) with different ratios of 1,3-bis(aminomethyl)cyclohexane (terafunctional amine) and cyclohexylmethylamine (difunctional amine). All samples are cured in CO2-free air. Both the film surface in contact with air and that in contact with the silicon substrate (the interface) are analyzed using atomic force microscopy (AFM) and nanoindentation. Small angle neutron scattering (SANS), attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, and contact angle measurements, are used to assist in the interpretation of AFM results. Substantial morphological and mechanical differences are observed between the surface and the interface for different crosslinked epoxies. The findings have strong implications on the wettablity, adhesion, and durability of amine-cured epoxies.

Diffusion of Cations Along the Polymer/Metal Interface Under an Applied Electrical Potential

Diffusion of cations along the polymer/metal interface controls the rate of blistering of polymer coatings on metals exposed to electrolytes. Cations are driven by both concentration and electrical potential gradients. A theoretical and experimental study was carried out on the diffusion of sodium ion along the polymer coating/steel interface under an applied potential. Mathematical models, consisting of initial and propagation stages, are derived based on a moving boundary diffusion problem. Model variables include ion diffusivity, potential gradient and distance between defects and delamination sites. Models are solved to predict ion fluxes and concentration in the blistering areas. Experimental data are analyzed to extract model parameters. Model predictions agreed well with experimental data and practical observations

Interfacial Water and Adhesion Loss of Polymer Coatings on a Siliceous Substrate

Water is often the main cause of adhesion loss of a polymer coating/substrate system. The buildup of the interfacial water layer and the loss of adhesion of polymer-coated siliceous substrates exposed to liquid water has been investigated. The thickness of the interfacial water layer was measured on epoxy-coated SiO2-Si prisms using FTIR-multiple internal reflection (FTIR-MIR) spectroscopy. Adhesion loss on flat siliceous substrates was determined by a wet peel test on epoxy-coated SiO2-Si wafers and adhesion loss of composites was obtained by measuring the interlaminar shear strengths of epoxy/E-glass fiber composites. Both untreated and 0.1 % silane-treated substrates were used. Little water was observed at the interface of the silanetreated samples but about 10 monolayers of water have accumulated at the interface of the untreated samples after 100 h of exposure to 24°C water. Untreated, flat substrates lost most of their bonding strengths within 75 h of exposure but silane-treated specimens retained 80% of their adhesion after 600 h of exposure to 24°C water. Adhesion loss of untreated composites immersed in 60°C water was greater than that of treated samples; however, the rate of loss of both silanetreated and untreated composites was much lower than that of flat substrates. Adhesion loss was found to follow the same trend as interfacial water buildup.

Agonists at the δ-opioid receptor modify the binding of µ-receptor agonists to the µ-δ receptor hetero-oligomer

BACKGROUND AND PURPOSE

µ- and δ-opioid receptors form heteromeric complexes with unique ligand binding and G protein-coupling profiles linked to G protein α z-subunit (Gα(z) ) activation. However, the mechanism of action of agonists and their regulation of the µ-δ receptor heteromer are not well understood.

EXPERIMENTAL APPROACH

Competition radioligand binding, cell surface receptor internalization in intact cells, confocal microscopy and receptor immunofluorescence techniques were employed to study the regulation of the µ-δ receptor heteromer in heterologous cells with and without agonist exposure.

KEY RESULTS

Gα(z) enhanced affinity of some agonists at µ-δ receptor heteromers, independent of agonist chemical structure. δ-Opioid agonists displaced µ-agonist binding with high affinity from µ-δ heteromers, but not µ receptor homomers, suggestive of δ-agonists occupying a novel µ-receptor ligand binding pocket within the heteromers. Also, δ-agonists induced internalization of µ-opioid receptors in cells co-expressing µ- and δ-receptors, but not those expressing µ-receptors alone, indicative of µ-δ heteromer internalization. This dose-dependent, Pertussis toxin-resistant and clathrin- and dynamin-dependent effect required agonist occupancy of both µ- and δ-opioid receptors. In contrast to µ-receptor homomers, agonist-induced internalization of µ-δ heteromers persisted following chronic morphine exposure.

CONCLUSIONS AND IMPLICATIONS

The µ-δ receptor heteromer may contain a novel δ-agonist-detected, high-affinity, µ-receptor ligand binding pocket and is regulated differently from the µ-receptor homomer following chronic morphine exposure. Occupancy of both µ- and δ-receptor binding pockets is required for δ-agonist-induced endocytosis of µ-δ receptor heteromers. δ-Opioid agonists target µ-δ receptor heteromers, and thus have a broader pharmacological specificity than previously identified.

Multistate outbreak of Escherichia coli O157:H7 infections associated with a national fast-food chain, 2006: a study incorporating epidemiological and food source traceback results

A multistate outbreak of Escherichia coli O157:H7 infections occurred in the USA in November-December 2006 in patrons of restaurant chain A. We identified 77 cases with chain A exposure in four states - Delaware, New Jersey, New York, and Pennsylvania. Fifty-one (66%) patients were hospitalized, and seven (9%) developed haemolytic uraemic syndrome; none died. In a matched analysis controlling for age in 31 cases and 55 controls, illness was associated with consumption of shredded iceberg lettuce [matched odds ratio (mOR) 8·0, 95% confidence interval (CI) 1·1-348·1] and shredded cheddar cheese (mOR 6·2, CI 1·7-33·7). Lettuce, an uncooked ingredient, was more commonly consumed (97% of patients) than cheddar cheese (84%) and a single source supplied all affected restaurants. A single source of cheese could not explain the regional distribution of outbreak cases. The outbreak highlights challenges in conducting rapid multistate investigations and the importance of incorporating epidemiological study results with other investigative findings.

Capecitabin (Cap) compared with flurorouracil (5FU)-leucovorin (LV) as concurrent chemotherapy for preoperative chemoradiation (preop CRT) in rectal cancers: A retrospective study

606

Background: The aim was to compare acute toxicities, compliance to treatment and tumor response after preoperative chemoradiation between two different regimen of concurrent chemotherapy, Cap or 5FU-LV, for the treatment of locally advanced rectal cancers.

Methods: Patients with a resectable rectal cancer (T3-4, N0-2) treated from 1993 to 2006 were included. We compared two groups of patients. One treated with preop CRT including 5FU-LV (5FU 350 mg/m2 short IV infusion daily for 5 days - week 1 and 5. LV IV push 20mg/m2 with 5FU. RT 45 Gy 1.8 Gy/F over 5 weeks). The second group received the same RT scheme. 5FU-LV were substitute for Cap 850 mg/m2 twice daily along the RT except week-end.

Results: 101 patients received 5 FU-LV and 51 patients Cap. Patients and tumour characteristics were similar. Grade 3-4 acute toxicities rates (especially leucopenia and diarrheas) after chemoradiation were 4 and 9.8% for 5 FU-LV and Cap respectively (p=0.16). Chemotherapy was modified for toxicities (dose reduction or interruption) in 5.9 and 17.6% of patients receiving 5 FU-LV and Cap respectively (p=0.04). Radiotherapy was stopped in 7.9 and 3.9% of patients treated by 5 FU-LV and Cap respectively (p=0.50). Complete histological response rates were 10.3 and 6% (p=0.54), tumour regression (downstaging) rates were 44.3 and 41.2% (p=0.73) for patients treated by 5 FU-LV and Cap respectively.

Conclusions: In this retrospective analysis CRT with Cap obtained a similar tumor effect to the 5 FU-LV scheme. However the Cap scheme induced more grade 3-4 toxicities had no impact on the RT compliance but conducted to modify more frequently the chemotherapy scheme.

No significant financial relationships to disclose.

Evaluation of steady-state pharmacokinetic interactions between ritonavir-boosted BILR 355, a non-nucleoside reverse transcriptase inhibitor, and lamivudine/zidovudine in healthy subjects

WHAT IS KNOWN AND OBJECTIVE

BILR 355 is a second generation non-nucleoside reverse transcriptase inhibitor. It has shown promising in vitro anti-HIV-1 activities and favourable human pharmacokinetic properties after co-administration with ritonavir (RTV). Lamivudine (3TC) is a nucleoside reverse transcriptase inhibitor. It is excreted predominantly in urine by a transporter-mediated pathway. These two drugs are likely to be given together to HIV-infected patients. The objective of this study was to investigate any steady-state pharmacokinetic interactions between RTV-boosted BILR 355 and 3TC/zidovudine (ZDV).

METHODS

This was a randomized, open label, prospective study. In group A, 39 healthy subjects were given 3TC/ZDV (150 mg/300 mg) twice daily (b.i.d.) for 7 days, and then BILR 355 and RTV (BILR 355/r, 150 mg/100 mg) were co-administered with this regimen for an additional 7 days. Intensive blood samples were taken on days 7 and 14 for pharmacokinetic assessments. In group B, 12 healthy subjects were given BILR 355/r (150 mg/100 mg) b.i.d. for 7 days. The pharmacokinetic data from group B were pooled with data from group B subjects in other similar studies performed in parallel (BILR 355 alone group in BILR 355 drug-drug interaction studies with tipranavir, lopinavir/RTV, and emtricitabine/tenofovir DF; BILR 355 regimen was the same).

RESULTS AND DISCUSSION

After co-administration with BILR 355/r, the AUC(12,ss) and C(max,ss) of 3TC increased by 45% and 24%, respectively; the elimination half-life (t(1/2) ,ss) of 3TC was significantly increased. However, the pharmacokinetics of ZDV was unchanged. Co-administration with 3TC/ZDV resulted in a 22% decrease in AUC(12,ss) and a 20% decrease in C(max,ss) for BILR 355. The observed increase in exposure and prolongation of t(1/2,ss) of 3TC is potentially related to inhibition of OCT-mediated urinary excretion of 3TC.

WHAT IS NEW AND CONCLUSION

Concomitant administration of BILR 355 with 3TC/ZDV resulted in a modest decrease in exposure to BILR 355 and a 45% increase in exposure to 3TC.

Effects of the local environment on CNT-based nanoelectronics: development of a microenvironment probe station

In this study, we report the development of a microenvironment probe station capable of detecting the effect of small changes to the local environment around a carbon nanotube conduction channel. The microenvironment probe station is highly versatile and is used to characterize alterations in carbon nanotube field effect transistor electrical behavior in response to changes in temperature, gas species, infrared and ultraviolet light. All devices were electrically characterized in atmospheric, ultrahigh vacuum and oxygen-rich environments. The results suggest that devices could be changed from n-type at 1 x 10(-8) torr through an intermediate ambipolar state at 1 x 10(-4) torr to p-type at atmosphere solely by increasing the oxygen concentration. The average resistance of these carbon nanotube field effect transistors after annealing was observed to decrease by approximately 54% from their initial value under ultrahigh vacuum to their final value in the presence of pure oxygen while corresponding threshold voltages shifts were also observed. Illumination with infrared light resulted in a approximately 10% increase in drain current with an estimated response time <1 fs due to photon-induced electron-hole pair generation. Illumination with ultraviolet light resulted in approximately 5-15% reduction in drain current due to photon-induced desorption of oxygen adsorbate.