Magnetic Resonance Imaging Estimation of Longitudinal Relaxation Rate Change (ΔR1) in Dual Gradient Echo Sequences Using an Adaptive Model

Magnetic Resonance Imaging (MRI) estimation of contrast agent concentration in fast pulse sequences such as Dual Gradient Echo (DGE) imaging is challenging. An Adaptive Neural Network (ANN) was trained with a map of contrast agent concentration estimated by Look-Locker (LL) technique (modified version of inversion recovery imaging) as a gold standard. Using a set of features extracted from DGE MRI data, an ANN was trained to create a voxel based estimator of the time trace of CA concentration. The ANN was trained and tested with the DGE and LL information of six Fisher rats using a K-Fold Cross-Validation (KFCV) method with 60 folds and 10500 samples. The Area Under the Receiver Operator Characteristic Curve (AUROC) for 60 folds was used for training, testing and optimization of the ANN. After training and optimization, the optimal ANN (4:7:5:1) produced maps of CA concentration which were highly correlated (r =0.89, P < 0.0001) with the CA concentration estimated by the LL technique. The estimation made by the ANN had an excellent overall performance (AUROC = 0.870).

Naloxone in the management of hepatic encephalopathy

BACKGROUND/AIM

This study aimed to assess the effectiveness and safety of naloxone in the management of hepatic encephalopathy (HE).

METHODS

Cochrane collaboration methodology was used in a meta-analysis of randomized controlled trials of naloxone therapy for HE.

RESULTS

Seventeen randomized trials were identified with 15 studies involving 1054 patients meeting criteria for inclusion. Naloxone use was associated with a significant improvement in HE [relative risk (RR) 1.46; 95% confidence interval (CI) 1.27-1.67; P = 0.0005]. This comparison showed statistical heterogeneity (P < 0.10, and χ2 = 44.93). Subgroup analysis indicated naloxone administered parenterally by intermittent or continuous infusions to be effective (RR 1.34; 95% CI 1.17-1.53; P < 0.0001). A significant in trials by infusion route (RR 1.42; 95% CI 1.19-1.69; P < 0.0001) interaction was observed.

CONCLUSIONS

Naloxone may improve HE. However, published data are limited.

Abstract P1-13-05: The Effect of Treatment with Denosumab or Zoledronic Acid on Health-Related Quality of Life in Patients with Metastatic Breast Cancer

Background: Patients with breast cancer and bone metastases often experience skeletal-related events (SREs) and pain, which may impact health-related quality of life (HRQoL). Denosumab is a fully human monoclonal antibody against RANKL shown to be superior in delaying/preventing SREs and more effective in delaying moderate or severe pain in patients with advanced breast cancer compared with zoledronic acid (ZA). Previously reported results from this study population showed that both denosumab and ZA patients showed improvement or maintenance in HRQoL relative to baseline (BL), and a greater proportion of denosumab-treated patients had a clinically meaningful improvement in HRQoL. We now describe the effect of denosumab and ZA treatment on HRQoL among patients with varying degrees of pain at BL.

Methods: Enrolled patients received subcutaneous (SC) denosumab 120 mg or intravenous (IV) ZA 4 mg every 4 weeks in a double-blind, double-dummy fashion. Pain was evaluated using the Brief Pain Inventory — Short Form (BPI). Patients were divided into 2 subgroups based on the level of pain reported at BL: no/mild pain or moderate/severe pain. Patients completed the Functional Assessment of Cancer Therapy-General (FACT-G) questionnaire at BL, day 8, and before each monthly visit to assess overall HRQoL. Higher scores (range 0 to 108) represent better HRQoL. Improvement, maintenance, and worsening of HRQoL were assessed through month 18, when 30% of patients had dropped out due to death, disease progression, or withdrawal of consent. A change of ≥5 points (increase or decrease) in the FACT-G total score was considered a meaningful improvement.

Results: Among patients who reported no/mild pain at baseline, more denosumab-treated patients had a ≥5-point increase in their FACT-G score from month 4 onwards. Over the 18 month period, an average of 4.1% more (range: −0.6% to 9.3%) denosumab-treated patients experienced meaningful improvement in HRQoL than ZA-treated patients. There were also fewer denosumab-treated patients experiencing ≥5-point decrease in HRQoL over 18 months (average of 2.4% fewer [range:-4.4% to 6.3% fewer]). Similar patterns were also noted for patients with moderate/severe pain at baseline. An average of 3.0% more (range:-1.7% to 7.9%) denosumab-treated patients had ≥5-point increase in FACT-G scores compared with ZA-treated patients over 18 months. A lower proportion of denosumab-treated patients (3.5% fewer [range: −1.1% to 11.5% fewer]) than ZA-treated patients had a decrease ≥5-points in their FACT-G score over 18 months.

Conclusion: In patients with breast cancer and bone metastases, a greater proportion treated with denosumab than ZA had a meaningful improvement in HRQoL regardless of their pain level at BL.

Citation Information: Cancer Res 2010;70(24 Suppl):Abstract nr P1-13-05.

Association of single-nucleotide polymorphisms in HLA class II/III region with knee osteoarthritis

OBJECTIVE

A genome-wide association study and a replication using Japanese, Spanish and Greek Caucasian populations have recently indicated two single-nucleotide polymorphisms (SNPs) (rs7775228 and rs10947262) associated with knee Osteoarthritis (OA) susceptibility. We have further evaluated the association in knee OA subjects from Han Chinese and Australian Caucasian origin.

METHODS

Two independent case-control association studies were performed using Han Chinese and Australian Caucasian populations. The two SNPs were genotyped in patients who had primary symptomatic knee OA with radiographic confirmation and/or received total knee replacement surgery as well as in matched controls. They were subjected to statistic analyses.

RESULTS

A total of 991 OA patients and 1536 controls were genotyped. No significant difference was detected in genotype or allele frequencies of the two SNPs between knee OA and control groups in the two populations (all P>0.05). The association was also negative even after stratification by sex, body mass index (BMI) and Kellgren/Lawrence scores. The significant heterogeneity was detected between Chinese and Japanese (both P<0.05). In the Caucasian samples, no significant heterogeneity was detected (both P>0.05). The result of meta-analysis showed significant association between knee OA and rs10947262 in total subjects [summary OR=1.26, 95%confidence intervals (CI)=1.07-1.27, P=3 × 10(-8)] and in Caucasian samples (summary OR=1.28, 95%CI=1.04-1.57, P=0.02).

CONCLUSION

We demonstrated no association between the two SNPs in human leukocyte antigen (HLA) class II/III region and knee OA in Han Chinese population. A significant association was detected between SNP rs10947262 and knee OA in Caucasian subjects. Further replication studies are required to identify the impact of controversial association.

Comparison of the safety and efficacy of cyclosporine minimization versus cyclosporine elimination in de novo renal allograft patients receiving sirolimus

The safety and efficacy of concentration-controlled use of sirolimus (SRL) and cyclosporine (CsA) followed by CsA minimization (CsAm) or elimination (CsAe) beginning at week 13 was compared in a phase 4, open-label, randomized (1:1) trial of renal transplant recipients enrolled between March 2004 and November 2005. The primary endpoint was renal function, measured at 12 months using the Nankivell formula, in patients remaining on therapy. Though a total enrollment of 140 patients in each group was planned to provide an 80% power to detect a difference in means, only 207 subjects were enrolled in this study. Demographic characteristics were similar between groups, with 98.1% recipients of first grafts, 69.1% from living donors, and 7.2% diabetics. At 12 months, there were no differences in renal function (61.08 vs 65.24 mL/min, P = .132); incidence of biopsy-confirmed acute rejection (14.3% vs 22.5%, P = .152); and patient (89.5% vs 92.2%, P = .632), graft (87.6% vs 88.2%, P = .999), and death-censored graft (98.1% vs 94.1%, P = .166) survivals between CsAm and CsAe groups, respectively. There were no differences in the overall rate of study-drug discontinuation (32.4% vs 36.3%, P = .562) but more patients discontinued because of lack of efficacy/graft loss in the CsAe group (4.8% vs 14.7%, P = .018). This study was underpowered to demonstrate the superiority of one regimen over the other. In summary, SRL immunotherapy combined with CsA minimization or elimination showed comparative safety and efficacy. Both regimens offer potential treatment options for de novo renal allograft recipients.

Highly Efficient Near-IR Photoluminescence of Er Immobilized in Mesoporous SBA-15

SiO(2) mesoporous molecular sieve SBA-15 with the incorporation of erbium ions is studied as a novel type of nanoscopic composite photoluminescent material in this paper. To enhance the photoluminescence efficiency, two schemes have been used for the incorporation of Er(3+) where (1) Er(3+) is ligated with bis-(perfluoromethylsulfonyl)-aminate (PMS) forming Er(PMS)(x)-SBA-15 and (2) Yb(3+) is codoped with Er(3+) forming Yb-Er-SBA-15. As high as 11.17 × 10(-21)cm(2) of fluorescent cross section at 1534 nm and 88 nm of "effective bandwidth" have been gained. It is a 29.3% boost in fluorescent cross section compared to what has been obtained in conventional silica. The upconversion coefficient in Yb-Er-SBA-15 is relatively small compared to that in other ordinary glass hosts. The increased fluorescent cross section and lowered upconversion coefficient could benefit for the high-gain optical amplifier. Finally, the Judd-Ofelt theory has also been used for the analyses of the optical spectra of Er(PMS)(x)-SBA-15.

Electron scattering and electrical conductance in polycrystalline metallic films and wires: impact of grain boundary scattering related to melting point

For electrical conductance in polycrystalline metallic films and wires, the reflection coefficient of electrons at grain boundaries is explored and found to be proportional to the square root of the melting points of metals. As validated by available experimental results, this exploration enables classical models to take an essential role in theoretically predicting the electrical conductance of low-dimensional metals. One thus sees that the mechanism dominating the suppression of electrical conductance is transformed from the surface scattering into the grain boundary scattering as the ratio of film thickness (or wire diameter) to grain size rises. Furthermore, the impact of grain boundary scattering becomes less important for metals with lower melting points.

Novel and recurrent TRPV4 mutations and their association with distinct phenotypes within the TRPV4 dysplasia family

BACKGROUND

Mutations in TRPV4, a gene that encodes a Ca(2+) permeable non-selective cation channel, have recently been found in a spectrum of skeletal dysplasias that includes brachyolmia, spondylometaphyseal dysplasia, Kozlowski type (SMDK) and metatropic dysplasia (MD). Only a total of seven missense mutations were detected, however. The full spectrum of TRPV4 mutations and their phenotypes remained unclear.

OBJECTIVES AND METHODS

To examine TRPV4 mutation spectrum and phenotype-genotype association, we searched for TRPV4 mutations by PCR-direct sequencing from genomic DNA in 22 MD and 20 SMDK probands.

RESULTS

TRPV4 mutations were found in all but one MD subject. In total, 19 different heterozygous mutations were identified in 41 subjects; two were recurrent and 17 were novel. In MD, a recurrent P799L mutation was identified in nine subjects, as well as 10 novel mutations including F471del, the first deletion mutation of TRPV4. In SMDK, a recurrent R594H mutation was identified in 12 subjects and seven novel mutations. An association between the position of mutations and the disease phenotype was also observed. Thus, P799 in exon 15 is a hot codon for MD mutations, as four different amino acid substitutions have been observed at this codon; while R594 in exon 11 is a hotspot for SMDK mutations.

CONCLUSION

The TRPV4 mutation spectrum in MD and SMDK, which showed genotype-phenotype correlation and potential functional significance of mutations that are non-randomly distributed over the gene, was presented in this study. The results would help diagnostic laboratories establish efficient screening strategies for genetic diagnosis of the TRPV4 dysplasia family diseases.

Inhibitory regulation of acid-sensing ion channel 3 by zinc

Acid-sensing ion channel 3 (ASIC3) is a proton-gated, voltage-insensitive Na(+) channel that is expressed primarily in peripheral sensory neurons and plays an important role in pain perception, particularly as a pH sensor following cardiac ischemia. We previously reported that ASIC3 currents are not affected by zinc at nanomolar concentrations. In this study, we examined the potential role of micromolar zinc in the regulation of ASIC3. In CHO cells expressing ASIC3, we found that ASIC3 currents triggered by dropping the pH from 7.4 to 6.0 were inhibited by pretreatment with zinc in a concentration-dependent manner; the half-maximum inhibitory concentration of zinc was 61 muM. ASIC currents activated by a relatively small drop in pH from 7.4 to 7.2 or 7.0 were also subject to inhibition by zinc. The inhibition was fast and pH independent, and occurred within a relatively narrow range of zinc concentrations between 30 and 300 muM. Further, increasing extracellular Ca(2+) concentrations from 2 to 10 mM failed to affect inhibition of ASIC3 currents by zinc. Experimentally elevating intracellular zinc levels did not affect the inhibition of ASIC3 currents by equal concentrations of extracellular zinc, and modification of cysteine or histidine residues had no effect on the inhibition of ASIC3 currents by zinc. These collective results suggest that zinc is an important regulator of ASIC3 at physiological concentrations, that zinc inhibits ASIC3 in a pH- and Ca(2+)-independent manner, and that inhibition of ASIC3 currents is dependent upon the interaction of zinc with extracellular domain(s) of ASIC3.

Effects of intermixing on modulation p-doped quantum dot superluminescent light emitting diodes

Different capping of quantum dot (QD) materials is known to produce different degrees of intermixing during a post-growth thermal annealing process. We report a study of the effect of different degrees of intermixing on modulation beryllium doped quantum dot superluminescent light emitting diodes (QD-SLEDs). The intermixed QD-SLEDs show high device performance whilst achieving a large central emission wavelength shift of approximately 100nm compared to the as-grown device. The evolution of the emission spectra and power with drive current suggest a transition from QD-like to QW-like behavior with increasing degree of intermixing. A selective area intermixed QD-SLED is demonstrated, and with optimized differential intermixing, such structures should allow ultra-broadband sources to be realized.

Effect of Saliva Contamination and Decontamination on Bovine Enamel Bond Strength of Four Self-etching Adhesives

Salivary contamination before and after priming could significantly reduce the enamel bond strength of self-etching adhesives. Proper isolation should be performed before and during application of the adhesives and placement of the resin composite. Thorough water-spraying could significantly improve the μTBS of saliva-contaminated enamel.

Reply to comment on 'Modelling of surface energies of elemental crystals'

In reply to the comment by Luo et al, our theoretical model for the surface energy of elemental crystals is further developed to improve the prediction accuracy of the surface energy of the high-Miller-index facets. It is considered that the previous predicted unit surface area could not denote the actual one since the facets now are uneven. With the modification, the accuracy for the prediction of surface energy in units of J m(-2) is improved.

Characterization of acid-sensing ion channels in medium spiny neurons of mouse striatum

Acid-sensing ion channels (ASICs) regulate synaptic activities and play important roles in neurodegenerative diseases. They are highly expressed in the striatum, where medium spiny neurons (MSNs) are a major population. Given that the properties of ASICs in MSNs are unknown, in this study, we characterized ASICs in MSNs of the mouse striatum. A rapid drop in extracellular pH induced transient inward currents in all MSNs. The pH value for half-maximal activation was 6.25, close to that obtained in homomeric ASIC1a channels. Based on psalmotoxin 1 and zinc sensitivity, ASIC1a (70.5% of neurons) and heteromeric ASIC1a-2 channels (29.5% of neurons) appeared responsible for the acid-induced currents in MSNs. ASIC currents were diminished in MSNs from ASIC1, but not ASIC2, null mice. Furthermore, a drop in pH induced calcium influx by activating homomeric ASIC1a channels. Activation of ASICs increased the membrane excitability of MSNs and lowering extracellular Ca2+ potentiated ASIC currents. Our data suggest that the homomeric ASIC1a channel represents a majority of the ASIC isoform in MSNs. The potential function of ASICs in the striatum requires further investigation.

A p-type-doped quantum dot superluminescent LED with broadband and flat-topped emission spectra obtained by post-growth intermixing under a GaAs proximity cap

Broadband superluminescent light emitting diodes are realized by a post-growth annealing process, on modulation p-doped multiple InAs/InGaAs/GaAs quantum dot layer structures, under a GaAs proximity cap. The device exhibits a large and flat emission with spectral width up to 132 nm at 2 mW. This is mainly attributed to the reduction of the energy separation between the ground state and the excited state, in addition to the optical quality of the intermixed modulation p-doped quantum dot materials being comparable to that of the as-grown sample.