A functionalized single-walled carbon nanotube-induced autophagic cell death in human lung cells through Akt-TSC2-mTOR signaling

Nanoparticles are now emerging as a novel class of autophagy activators. Functionalized single-walled carbon nanotubes (f-SWCNTs) are valuable nanomaterials in many industries. This article is designed to assess the autophagic response for f-SWCNTs exposure in vitro and in vivo. A few types of f-SWCNTs were screened in human lung adenocarcinoma A549 cells for the autophagic response and related pathways in vitro. Formation of autophagosomes and LC3-II upregulation were confirmed on the basis of electron microscopy and LC3 western blotting for COOH-CNT, but not for PABS-CNT and PEG-CNT. MTT assay showed marked increase in cell viability, when COOH-CNT was added to cells in the presence of autophagy inhibitor 3MA, ATG6 or TSC2 siRNA. Consistent with the involvement of the Akt–TSC1/2–mTOR pathway, the phosphorylation levels of mTOR, mTOR's substrate S6 and Akt were shown significantly decreased in A549 cells on treatment with COOH-CNT using western blotting. What's more, autophagy inhibitor 3MA significantly reduced the lung edema in vivo. In a word, COOH-CNT induced autophagic cell death in A549 cells through the AKT–TSC2–mTOR pathway and caused acute lung injury in vivo. Inhibition of autophagy significantly reduced COOH-CNT-induced autophagic cell death and ameliorated acute lung injury in mice, suggesting a potential remedy to address the growing concerns on the safety of nanomaterials.

Abstract 289: Associations between germline genotype and efficacy and safety outcomes in a phase III study of sunitinib (SU) and FOLFIRI in metastatic colorectal cancer (mCRC)

Introduction: SU is an oral, multitargeted inhibitor of VEGFRs, PDGFRs, KIT, FLT3, CSF-1R and RET. In a phase III mCRC study, adding SU to FOLFIRI did not improve progression-free survival (PFS) vs. FOLFIRI/placebo. Potential correlations were investigated between germline genotype and safety/efficacy endpoints among patients (pts) in this trial.

Methods: Blood sample donation for genotype analysis was optional. Selection of genes and polymorphisms was based on prior reported associations. Twenty-one single-nucleotide polymorphisms (SNPs) in 10 genes (VEGF-A, VEGFR-2, CYP1A1, ABCG2, ABCB1, ABCC2, MTHFR, UGT1A1, FLT1 and FLT3) were analyzed by TaqMan allelic discrimination assay or fragment analysis, using DNA isolated from peripheral blood samples. All 21 polymorphisms were analyzed for associations with efficacy (PFS; overall survival [OS]) and selected safety endpoints. Results were adjusted for multiple testing of SNPs in linkage disequilibrium.

Results: Genotyping was performed in 139/768 pts (18%). Age and gender were similar between genotyped and non-genotyped pts, but the genotyped subset had fewer non-Caucasians (13% vs. 39%; Fisher's exact P<0.0001). Therefore, the statistical analysis reported here included Caucasians only. OS was superior in genotyped vs. non-genotyped pts (log rank P<0.0001). For the FOLFIRI/placebo arm only, the ABCC2 gene SNP rs717620 was associated with increased grade 3/4 diarrhea for those with the T allele (0/37 for C/C, 2/15 for C/T, 2/2 for T/T; Fisher's exact P=0.0003), and remained statistically significant after multiple testing adjustment. In the SU/FOLFIRI arm only, the common homozygous genotype A/A in the CYP1A1 gene at rs1048943 was associated with increased grade 3/4 neutropenia (39/59 for A/A, 1/6 for A/G, # of G/G = 0; Fisher's exact P=0.028), but lost significance after multiple testing adjustment. In the FOLFIRI/placebo arm only, a weak association was observed between poorer PFS and the common homozygous genotype T/T for the rs1045642 SNP (C3435T) in the ABCB1 gene (median [T/T] = 36 weeks [95% CI 24.9-40.6]; median [T/C] = 45 weeks [41.9-83.6]; median [C/C] = 55.1 weeks [31.8-55.1], HR [T/C vs. T/T] = 0.21 [95% CI 0.07-0.64]; HR [C/C vs. T/T] = 0.23 [95% CI 0.07-0.81]; log rank P=0.008; not significant after multiple testing adjustment).

Conclusions: Presence of the T allele in the ABCC2 gene at rs717620 was associated with increased risk of grade 3/4 diarrhea in a small number of Caucasian pts receiving FOLFIRI/placebo. No significant associations were identified between genotype and safety/efficacy endpoints in pts who received SU/FOLFIRI. As OS was superior in genotyped vs. non-genotyped pts, correlative findings may not be extrapolated beyond the genotyped subset. Further analysis of baseline characteristics is underway in the genotyped group to investigate this difference.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 289. doi:10.1158/1538-7445.AM2011-289

Abstract 2935: Anti-proliferative and pro-apoptotic effects of Olaparib, in triple negative subset of breast cancer: Does tumor suppressor PTEN play a role

Triple-negative breast tumors (TNBT) are associated with poor prognosis and high recurrence-rates after adjuvant therapy. Currently, there is no preferred standard form of chemotherapy for TNBT. Landmark studies on DNA damage checkpoints and associated repair function in preneoplastic and neoplastic cells have focused attention on the importance of the BRCA-RAD51 repair-pathway in the development and progression of TNBC. The PARP inhibitor (PARPi), Olaparib, is currently being tested in phase I / II trials in BC and holds promise for the treatment of BRCA-deficient basal-like and /or TNBC. PTEN protein/function is downregulated in ∼ 40% of breast cancer, including TNBT, and a recurrent gross-mutation of the PTEN gene is identified in breast cancer with deficient double-strand base-repair. We hypothesize that there is a cellular threshold for error-free DNA-repair in TNBT cells and that the absence of PTEN can sensitize these cells to a concurrent treatment of DNA-damaging agent (carboplatin) and PARPi (Olaparib). We determined: (a) the time course of expression of PAR protein following Olaparib in BRCA-incompetent TNBT cell lines, (b) enzymatic activity of PARPi in BRCA-competent MDA-MB-231(PTEN+), MDA468 (PTEN-null), and BT20, TNBT cells, (c) pro-apoptotic signals in both BRCA1-incompetent and BRCA1-competent TNBT cells, (d) anti-proliferative effect of Olaparib plus carboplatin on cell- survival (MTT assay, EC50s, automated live-cell counter), and 2D clonogenic assay. We have demonstrated: (1) a time dependent decrease in PAR expression with little alteration in the expression of total PARP within 24 hours of treatment of Olaparib in HCC1937 cells, (2) a comparable pattern of decrease in the levels of PAR expression in MDA-MB-231, MDA468, and BT20 cells following Olaparib and carboplatin at 24 and 48 hours, (3) a significant increase in the expression of cleaved-caspase 3 and 9, (4) a significant increase in the expression of cleaved-PARP, a downstream product of cleaved-caspase 3, (5) an increase in the TUNNEL-positive cells in response to Olaparib plus carboplatin and (6) a significant decrease in the percentage of cell-survival following combination-treatment. Strikingly, we found that amongst different BRCA-competent TNBT cells, PTEN-null MDA-MB468 cells appeared the most sensitive to the combination of Olaparib plus carboplatin with respect to EC50s, clonogenic assay, pro-apoptotic signals, and cell survival. Herein, we report a non-redundant function of PTEN in PARPi-mediated anti-proliferative and pro-apoptotic signals in TNBC. We are currently pursuing studies a) to delineate the mechanistic relationship between the thresholds of DNA repair and PTEN and b) to understand the phosphatase-independent role of PTEN in PARPi-mediated anti-proliferative / pro-apoptotic signals, the results of which will be presented in the meeting.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 2935. doi:10.1158/1538-7445.AM2011-2935

Lateral cephalometry changes after SARPE

Surgically assisted rapid palatal expansion (SARPE) is associated with postoperative cephalometric changes. In this study we analyse these changes in the sagittal plane in orthognathic patients undergoing SARPE followed by orthodontic treatment and Le Fort I, bilateral sagittal split osteotomy (BSSO), or bimaxillary surgery. This is a retrospective review of 50 patients (20 males, 30 females) undergoing orthognathic treatment with SARPE to correct transversal deficiency of the maxilla as part of a comprehensive treatment plan. PP-SN, SNA, and ANB angles were increased and U1-SN and U1-PP angles were decreased. All changes were statistically significant. Changes of SNB, PP-Mand plane angle, and SN-Mand. plane angle were not statistically significant. Surgically assisted rapid palatal expansion using a bone-borne appliance as a preparative step for later orthognathic surgery results in clockwise rotation of the maxilla.

The novel phospho-non-steroidal anti-inflammatory drugs, OXT-328, MDC-22 and MDC-917, inhibit adjuvant-induced arthritis in rats

BACKGROUND AND PURPOSE

The use of non-steroidal anti-inflammatory drugs (NSAIDs) in the treatment of rheumatoid arthritis (RA) is limited by their toxicity. We evaluated the anti-inflammatory efficacy and safety of three novel modified NSAIDs, phospho-aspirin, phospho-ibuprofen and phospho-sulindac.

EXPERIMENTAL APPROACH

We determined the anti-inflammatory effects and gastrointestinal safety of the phospho-NSAIDs in the rat adjuvant arthritis model and studied their mechanism of action in cultured cells, Cytokines were measured with elisa and activation of nuclear factor-κB (NF-κB) by immunohistochemistry.

KEY RESULTS

All three phospho-NSAIDs showed less gastrointestinal toxicity than their parent compounds and demonstrated strong anti-inflammatory effects, essentially reversing joint inflammation and oedema. They have a broad but not uniform effect on the expression of relevant cytokines, in general decreasing IL-6 and IL-1β and increasing IL-10 levels in rat plasma and cultured cells. Phospho-sulindac and phospho-ibuprofen but not phospho-aspirin suppressed PGE(2) production in vitro, whereas phospho-aspirin (in contrast to aspirin) showed the same effect in vivo. In joint tissues, phospho-aspirin inhibited NF-κB activation, and suppressed inflammation and bone resorption. Phospho-aspirin also inhibited Jurkat T cell proliferation. In general, phospho-aspirin had greater efficacy but different effects upon inflammatory mediators compared with aspirin. The chemical modification of the parent NSAIDs seems crucial for their safety and efficacy.

CONCLUSIONS AND IMPLICATIONS

Phospho-aspirin, phospho-ibuprofen and phospho-sulindac were safer than their parent NSAIDs, were highly effective in rat adjuvant arthritis and inhibited many key mediators in the pathophysiology of RA. These novel compounds are promising candidate drugs for the treatment of RA and merit further evaluation.

Accumulation and distribution of α-synuclein and ubiquitin in the CNS of Gaucher disease mouse models

Gaucher disease, a prevalent lysosomal storage disease, is caused by insufficient activity of acid β-glucosidase (GCase) and resultant glucosylceramide accumulation. Recently in Parkinson disease (PD) patients, heterozygous mutations in GCase have been associated with earlier onset and more progressive PD. To understand the pathogenic relationships between GCase variants and Parkinsonism, α-synuclein and ubiquitin distributions and levels in the brains of several mouse models containing GCase variants were evaluated by immunohistochemistry. Progressive α-synuclein and ubiquitin aggregate accumulations were observed in the cortex, hippocampus, basal ganglia, brainstem, and some cerebellar regions between 4 and 24 weeks in mice that were homozygous for GCase [D409H (9H) or V394L (4L)] variants and also had a prosaposin hypomorphic (PS-NA) transgene. In 4L/PS-NA and 9H/PS-NA mice, this was coincident with progressive neurological manifestations and brain glucosylceramide accumulation. Ultrastructural studies showed electron dense inclusion bodies in neurons and axons of 9H/PS-NA brains. α-synuclein aggregates were also observed in ventricular, brainstem, and cerebellar regions of older mice (>42-weeks) with the GCase variant (D409H/D409H) without overt neurological disease. In a chemically induced GCase deficiency, α-synuclein aggregates and glucosylceramide accumulation also occurred. These studies demonstrate a relationship between glucosylceramide accumulation and α-synuclein aggregates, and implicate glucosylceramide accumulation as risk factor for the α-synucleinopathies.

Protective effects of grape seed procyanidin extract against nickel sulfate-induced apoptosis and oxidative stress in rat testes

This study determined whether nickel sulfate (Ni)-induced reproductive damage occurs via apoptosis and oxidative stress and to examine the expression of Bax and c-kit and their effects on Ni exposure. The study also explored the protective effects of grape seed proanthocyanidin extract (GSPE) against Ni toxicity in the testes. Wistar rats were treated with normal saline, Ni alone (1.25, 2.5, and 5 mg/kg/day), and Ni (2.5 mg/kg/day) plus GSPE (50 and 100 mg/kg/day). After 30 days, Ni significantly decreased sperm motility and the percentage of S-phase cells and enhanced testicular apoptosis in the 2.5 and 5 mg groups. The levels of malondialdehyde (MDA), hydrogen peroxide (H₂O₂), and nitric oxide (NO) significantly increased. The decreased activity of glutathione peroxidase and catalase in the Ni groups showed that Ni could increase oxidative stress, especially at 2.5 and 5 mg. Western blot analysis showed that the expression of Bax protein and c-kit increased in 2.5 and 5 mg Ni groups compared with controls. Conversely, these changes were partially attenuated in rats simultaneously administered GSPE, especially in the 100 mg group. These results demonstrate the following: (1) Ni exhibits reproductive toxicity in rats by decreasing sperm at concentrations of 2.5 and 5 mg; (2) intratesticular apoptosis, oxidative stress, and c-kit overexpression play pivotal roles in reproductive damage induced by Ni; and (3) GSPE enhances sperm motility by down-regulating c-kit expression and offsetting the apoptosis and oxidative stress induced by Ni by directly decreasing MDA and NO, scavenging H₂O₂, and down-regulating Bax expression.

Direct mass measurements of short-lived A=2Z-1 nuclides (63)Ge, (65)As, (67)Se, and (71)Kr and their impact on nucleosynthesis in the rp process

Mass excesses of short-lived A=2Z-1 nuclei (63)Ge, (65)As, (67)Se, and (71)Kr have been directly measured to be -46,921(37), -46,937(85), -46,580(67), and -46,320(141)  keV, respectively. The deduced proton separation energy of -90(85)  keV for (65)As shows that this nucleus is only slightly proton unbound. X-ray burst model calculations with the new mass excess of (65)As suggest that the majority of the reaction flow passes through (64)Ge via proton capture, indicating that (64)Ge is not a significant rp-process waiting point.

Evolution of synonymous codon usage in Neurospora tetrasperma and Neurospora discreta

Neurospora comprises a primary model system for the study of fungal genetics and biology. In spite of this, little is known about genome evolution in Neurospora. For example, the evolution of synonymous codon usage is largely unknown in this genus. In the present investigation, we conducted a comprehensive analysis of synonymous codon usage and its relationship to gene expression and gene length (GL) in Neurospora tetrasperma and Neurospora discreta. For our analysis, we examined codon usage among 2,079 genes per organism and assessed gene expression using large-scale expressed sequenced tag (EST) data sets (279,323 and 453,559 ESTs for N. tetrasperma and N. discreta, respectively). Data on relative synonymous codon usage revealed 24 codons (and two putative codons) that are more frequently used in genes with high than with low expression and thus were defined as optimal codons. Although codon-usage bias was highly correlated with gene expression, it was independent of selectively neutral base composition (introns); thus demonstrating that translational selection drives synonymous codon usage in these genomes. We also report that GL (coding sequences [CDS]) was inversely associated with optimal codon usage at each gene expression level, with highly expressed short genes having the greatest frequency of optimal codons. Optimal codon frequency was moderately higher in N. tetrasperma than in N. discreta, which might be due to variation in selective pressures and/or mating systems.

Survey of fungi and yeast in polymicrobial infections in chronic wounds

OBJECTIVE

To assess the incidence, abundance and species diversity of fungi in chronic wounds, as well as to describe the associations of major fungi populations.

METHOD

Comprehensive molecular diagnostic reports were evaluated from a total of 915 chronic wounds in a retrospective study.

RESULTS

Of the 915 clinical specimens, 208 (23%) were positive for fungal species. These samples were further compared in a compiled dataset, and sub-classified among the four major chronic wound types (decubitus ulcer, diabetic foot ulcer, non-healing surgical wound, and venous leg ulcer). The most abundant fungi were yeasts in the genus Candida; however, Curvularia, Malessezia, Aureobasidium, Cladosporium, Ulocladium, Engodontium and Trichtophyton were also found to be prevalent components of these polymicrobial infections. A notable bacterial/fungal negative correlation was found to be apparent between Staphylococcus and Candida. There were also significant relationships between both bacterial and fungal genera and patient metadata including gender, diabetes status and cardiovascular comorbidities.

CONCLUSION

This microbial survey shows that fungi are more important wound pathogens and opportunistic pathogens than previously reported, exemplifying the impact of these under-reported pathogens. With the application of modern cost-effective and comprehensive molecular diagnostics, clinicians can now identify and address this significant component of chronic wound bioburden with targeted therapies, thereby improving healing trajectories.

AMG 386 in combination with sorafenib in patients (pts) with metastatic renal cell cancer (mRCC): A randomized, double-blind, placebo-controlled, phase II study

309

Background: AMG 386 inhibits angiogenesis by sequestering angiopoietin-1 and -2, thus preventing their interaction with the Tie2 receptor on endothelial cells. Combination with VEGF receptor inhibition has demonstrated additive effects in vivo. The efficacy and tolerability of sorafenib plus AMG 386, an investigational peptide-Fc fusion protein, were evaluated in mRCC pts.

Methods: Treatment-naive pts with clear cell mRCC were randomized 1:1:1 to sorafenib 400 mgPO BID plus AMG 386 10 mg/kg (Arm A) or 3 mg/kg (Arm B) QW; or placebo (Arm C) IV QW. Endpoints were progression-free survival (PFS; primary); and (secondary) objective response rate (ORR), change in tumor burden, adverse events (AEs) and pharmacokinetics. Tumor assessment was performed at baseline and every 8 weeks thereafter.

Results: 152 pts were randomized: Arms A/B/C, n=50/51/51. 60/61/61% of pts had intermediate and 40/39/37% had low MSKCC risk at baseline. PFS was similar in all 3 arms, whereas ORR was higher in the AMG 386 arms ( Table ). In Arms A/B/C the incidence of grade ≥ 3 AEs was 66/73/86% and serious AEs 36/49/28%. The most common AEs included diarrhea (70/67/56%; grade ≥3 8/10/8%), hand- foot syndrome (52/47/54%; grade ≥3 12/16/28%), alopecia (50/45/50%; grade ≥3 0/0/2%), and hypertension (42/49/46%; grade ≥3 18/20/14%). Median steady-state Cmax and Cmin for AMG 386 were similar to those reported previously. Sorafenib coadministration did not markedly affect AMG 386 exposure.

Conclusions: Sorafenib plus AMG 386 was tolerable but did not improve PFS compared with sorafenib plus placebo. Increased ORR and the observed reduction in tumor burden are suggestive of an antitumor effect of AMG 386 in mRCC.

[Table: see text]

[Table: see text]

Pharmacokinetics of dexmedetomidine in Chinese post-surgical intensive care unit patients

BACKGROUND

Dexmedetomidine is a rather new drug in China. We sought to describe the pharmacokinetics of dexmedetomidine in patients requiring post-operative sedation and ventilation in our surgical intensive care unit.

METHODS

Twenty-two patients received post-operative infusions of dexmedetomidine at 6 μg/kg/h for 10 min, followed by 0.4 μg/kg/h for 350 min. Venous blood samples were drawn and assayed for plasma concentration. The pharmacokinetics were analysed using a nonlinear mixed-effect model with an interindividual and intraindividual error model. An initial estimation was performed to determine which of the one-, two- or three-compartment models is best to describe the concentration-time data. The covariates age, gender, weight, height, lean body mass (LBM), body surface area (BSA) and body mass index (BMI) were tested for significant effects on parameters using a stepwise forward addition and backward elimination approach. Covariate effects were judged based on changes in the objective function value (OFV).

RESULTS

The pharmacokinetics of dexmedetomidine were best described by a three-compartment model. The model was further improved when height was a covariate of systemic clearance (Cl1), with a decrease in OFV by -13.56 (P<0.01). From the heights of 155-178 cm, Cl1 increased by approximately 143%. The final pharmacokinetic parameter values were as follows: V1 =63.4 l, V2=41.3 l, V3 =284.3 l, Cl1=0.47×(height/160 cm)(6.42) l/min, Cl2=2.43 l/min and Cl3=0.086 l/min.

CONCLUSIONS

This study identified (i) the effect of height on the pharmacokinetics of dexmedetomidine; (ii) that there is no influence of age, gender, weight, LBM, BSA and BMI on pharmacokinetic parameters; and (iii) it established a preliminary population pharmacokinetic model for Chinese patients.

Measurement of the parity-violating longitudinal single-spin asymmetry for W± boson production in polarized proton-proton collisions at sqrt[s] = 500 GeV

We report the first measurement of the parity-violating single-spin asymmetries for midrapidity decay positrons and electrons from W+ and W- boson production in longitudinally polarized proton-proton collisions at sqrt[s] = 500 GeV by the STAR experiment at RHIC. The measured asymmetries, A(L)(W+) = -0.27 ± 0.10(stat.) ± 0.02(syst.) ± 0.03(norm.) and A(L)(W-) = 0.14 ± 0.19(stat.) ± 0.02(syst.) ± 0.01(norm.), are consistent with theory predictions, which are large and of opposite sign. These predictions are based on polarized quark and antiquark distribution functions constrained by polarized deep-inelastic scattering measurements.

DMP1 processing is essential to dentin and jaw formation

Dentin matrix protein 1 (DMP1), an acidic protein that is essential to the mineralization of bone and dentin, exists as proteolytically processed fragments in the mineralized tissues. In this study, we characterized the tooth and jaw phenotypes in transgenic mice containing no wild-type DMP1, but expressing a mutant DMP1 in which Asp(213), a residue at one cleavage site, was replaced by Ala(213) (named "Dmp1-KO/D213A-Tg" mice). The teeth and mandible of Dmp1-KO/D213A-Tg mice were compared with those of wild-type, Dmp1-knockout (Dmp1-KO), and Dmp1-KO mice expressing the normal Dmp1 transgene. The results showed that D213A-DMP1 was not cleaved in dentin, and the expression of D213A-DMP1 failed to rescue the defects in the dentin, cementum, and alveolar bones in the Dmp1-KO mice. These findings indicate that the proteolytic processing of DMP1 is essential to the formation and mineralization of dentin, cementum, and jaw bones.

Randomized, double-blind, placebo-controlled phase II study of AMG 386 in combination with cisplatin and capecitabine (CX) in patients (pts) with metastatic gastroesophageal adenocarcinoma

66

Background: AMG 386, a first-in-class investigational peptide-Fc fusion protein (peptibody), blocks angiogenesis via inhibiting the interaction between angiopoietins-1 and -2 and the Tie2 receptor. We evaluated the efficacy and tolerability of AMG 386 or placebo plus CX in the first-line treatment of metastatic gastroesophageal adenocarcinoma.

Methods: Pts with confirmed metastatic adenocarcinoma of the stomach, gastroesophageal junction or distal esophagus were randomized 1:1:1 to receive CX (cisplatin, 80 mg/m2 IV Q3W; capecitabine, 1,000 mg/m2 orally BID for 14 days Q3W) plus AMG 386 10 mg/kg (Arm A), 3 mg/kg (Arm B), or placebo (Arm C) IV QW. The primary endpoint was progression-free survival (PFS). Secondary endpoints included objective response rate (ORR; in pts with measurable disease), adverse events (AEs), and pharmacokinetics (PK).

Results: 171 pts were randomized (Arm A/B/C, n = 56/59/56). Efficacy results are summarized in the table. The incidence of grade ≥ 3 AEs in Arms A/B/C was 80/84/75%. Serious AEs occurred in 73/60/47% and serious AEs grade ≥ 3 in 66/60/43% of pts. AEs in Arms A/B/C included abdominal pain (30/40/17%; grade ≥ 3, 18/3/4%), peripheral edema (13/29/6%; grade ≥ 3, 0/2/0%), venous thromboembolic events (20/22/19%; grade ≥ 3, 20/19/17%), and pulmonary embolism (9/3/15%; grade ≥ 3, 9/2/13%). Median AMG 386 Cmax and Cmin values at steady state after CX coadministration were dose-proportional. Coadministration with CX did not markedly affect AMG 386 exposure.

Conclusions: In this study, AMG 386 plus CX did not significantly improve PFS or ORR over placebo plus CX in this patient population. The toxicity of the combination of AMG 386 plus CX, compared with placebo, was greater but manageable. No unexpected AEs occurred.

[Table: see text]

[Table: see text]

Adjuvant chemotherapy for gastric cancer: Less drug, same efficacy

114

Background: Adjuvant chemotherapy is proved to improve survival in gastric cancer by meta-analyses. However, no evidence showed the best regimen. We conducted a retrospective analysis to compare triplets with doublets in the adjuvant setting.

Methods: We collected data from January 2004 to December 2008 from patients performed radical surgery and adjuvant chemotherapy. Doublets were defined as 5-FU 750 mg/m2 (d1- 5) or capecitabine 1,000 mg/m2 (d1-14) plus cisplatin 60 mg/m2 (d1) or oxaliplatin 130 mg/m2 (d1), while triplets had epirubicin 50 mg/m2 (d1) added. Chemotherapy was initiated within 6 weeks after surgery, repeated every three weeks and planned for 6 cycles. Patients were followed up in the outpatient clinic until death or April 30, 2010. Cox proportional-hazard model and chi-square test were used to test statistical difference.

Results: A total of 316 patients (210 in doublets, 106 in triplets) had a median follow-up time of 47 months. 77 patients died at the end of follow-up (3-year survival of 67.4%).Two groups were well balanced except age (median age of 57 in doublets, 51 in triplets, p < 0.001). All the patients tolerated well, with few grade 3/4 side effects (21.9% in doublets, 30.2% in triplets, p = 0.107). Two groups had similar disease-free survival (median DFS, 16 months vs. 23 months, p = 0.656) and overall survival (3-year survival rate, 59.6% vs. 64.8%, p = 0.293). Subgroup analysis showed the same benefit on survival between the two groups.

Conclusions: Our study suggested doublets and triplets had the same efficacy as the adjuvant chemotherapy. Furthermore, doublets seem more cost-effective.

[Table: see text]

No significant financial relationships to disclose.

Application of a modified linear solvation energy relationship (LSER) model to retention on a butylimidazolium-based column for high performance liquid chromatography

Previously, a new HPLC stationary phase based on n-butylimidazolium bromide was investigated using a linear solvation energy relationship (LSER) to systematically evaluate the intermolecular interactions between 32 test solutes and the stationary phase. The results and further comparisons with conventional reversed phase systems revealed that retention properties are similar to phenyl phases in both methanol/water and acetonitrile/water mixtures. In this work, the LSER model is extended by including the degree of ionization molecular descriptor, D, which takes into account the pK(a) of ionizable analytes and the pH of the mobile phase. The D molecular descriptor has been further divided into D(+) and D(-) components that separately account for the ionization of basic and acidic solutes, respectively. This is the first study where the ionization terms for weakly acidic solutes and weakly basic solutes have been separated. LSER results obtained with the expanded solute set with and without the inclusion of the D(+) and D(-) solute descriptors were compared. The improved correlation and standard error obtained for the expanded test set in the presence and absence of the D(+) and D(-) descriptors (R(2): 0.987 vs 0.846; SE: 0.051 vs 0.163 for 60% MeOH) support inclusion of these additional terms. Further, the coefficients obtained from the multiple linear regression for the expanded test set with the D(+) and D(-) descriptors were more consistent with the coefficients obtained when the test set included just neutral analytes. In addition, the expanded LSER model did a better job of predicting elution order for the ionizable analytes. This work provides further supporting evidence for the multimodal nature of the butylimidazolium stationary phase.

Binding of nickel to testicular glutamate-ammonia ligase inhibits its enzymatic activity

Exposure to nickel has been shown to cause damage to the testis in several animal models. It is not known if the testis expresses protein(s) that can bind nickel. To test this, we used a nickel-binding assay to isolate testicular nickel-binding proteins. We identified glutamate-ammonia ligase (GLUL) as a prominent nickel-binding protein by mass spectrometry. Protein analysis and reverse transcriptase polymerase chain reaction showed that GLUL is expressed in the testis, predominantly in interstitial cells. We determined that GLUL has a higher affinity for nickel than for its regular co-factor manganese. We produced an enzymatically active, recombinant GLUL protein. Upon binding, nickel interferes with the manganese-catalyzed enzymatic activity of recombinant GLUL protein. We also determined that GLUL activity in testes of animals exposed to nickel sulfate is reduced. Our results identify testicular GLUL as the first testicular protein shown to be affected by nickel exposure.