A phase I study of BMS-582664 (brivanib alaninate), an oral dual inhibitor of VEGFR and FGFR tyrosine kinases, in combination with full-dose cetuximab in patients (pts) with advanced gastrointestinal malignancies (AGM) who failed prior therapy

14018

Background: Brivanib is an oral prodrug of BMS-540215, a dual tyrosine kinase inhibitor of VEGFR and FGFR signaling. Prior studies have validated both VEGF and EGF signaling pathways as targets in AGM. The MTD of single-agent brivanib is 800 mg qd (ASCO #3051, 2006). Methods: An open-label Phase I dose-escalation study of brivanib in combination with cetuximab was conducted in pts with AGM who failed prior therapy. Brivanib was given po Day 1 and qd from Day 8, starting at 320 mg. Cetuximab was given IV Day 8 (400 mg/m2) then weekly (250 mg/m2). Dose escalation of brivanib continued to 800 mg qd, when an expansion cohort for pts with colorectal cancer (CRC) was opened for additional safety and efficacy. Fresh tissue and blood sampling for biomarker and pharmacokinetic (PK) analysis was performed. FDG-PET was obtained at Baseline X 2, Days 15 and 56. Tumor response (modified WHO) was evaluated q 8 weeks. Results: 18 pts (15 CRC, 2 esophageal, 1 other) were treated with 320, 600 or 800 mg qd of brivanib in combination with cetuximab for a median of 8 weeks (range 1 - 20+). A single DLT, bilateral pulmonary emboli, occurred at 320 mg qd. Few treatment-related AEs occurred across the 3 cohorts (Table). PK/biomarker data is pending. Available FDG-PET results from measurements in 8 pts with 2–3 target lesions showed good baseline reproducibility in SUVpeak, SUVmean and SUVmax, with intra-subject CV of 3.6%, 7.2% and 9.3%, respectively. Conclusions: Brivanib in combination with full-dose cetuximab was well tolerated at ≤800 mg qd and did not result in enhancement of cetuximab associated AEs. Pre-treatment FDG-PET is a highly reproducible imaging modality.

[Table: see text]

[Table: see text]

Removal of Ocular Artifacts from EEG: A Comparison of Adaptive Filtering Method and Regression Method Using Simulated Data

We recently proposed an adaptive filtering method for removing ocular artifacts from EEG recordings. In this study, the accuracy of this method is evaluated quantitatively using simulated data and compared with the accuracy of the time domain regression method. The results show that when transfer of ocular signal to EEG channel is frequency dependent, or when there is a time delay, the adaptive filtering method is more accurate in recovering the true EEG signals.

Computation within cultured neural networks

In this paper we present three related areas of research we are pursuing to study neural computation in vitro. Rat cortical neurons cultured on 60 channel multielectrode array (MEA) allow the researcher to measure from and stimulate sixty different sites across a small population of neurons grown in vitro. Using this system we can send stimulation patterns into the network and study how these living neural networks compute by measuring its outputs. Our first series of studies uses chaotic control techniques to study the dynamics and potentially control the behavior of cortical network. At the same time, we are beginning to apply a model of computation called the liquid state machine or LSM model developed by Wolfgang Maass to provide a firm mathematical framework from which to proceed with our investigations. Each of these components is integrated into a third area investigating the role of computation and feedback using a real-time sensory-motor feedback robotic flight system.

394 DEVELOPMENT OF A RAT ENDOMETRIAL SPHEROID AS A MODEL FOR THE ANALYSIS OF ENDOMETRIAL FUNCTIONS

The endometrium is one of the most complex tissues; it undergoes dynamic changes in response to implantation and pregnancy processes.An in vitro model may provide a tool for clarifying the complex implantation process. However, there is no suitable in vitro model for investigation of endometrial functions. The spheroid has been utilized in cell biology research because it appears to mimic the morphology and physiology of cells in living tissues and organs, which is unlike conventional monolayer culture. Multicellular spheroids composed of normal adult cells may provide a more useful model for the study of the endometrium. The purpose of the present study was to develop a spheroid composed of rat endometrial stromal (RES) cells as an in vitro model for analysis of endometrial functions. The RES were prepared from rat endometrium at Day 5 of pregnancy. Spheroids were generated using salmon aterocollagen (SAC). The cells were plated on 12-well SAC gels (Imoto Suisan Co.) and cultured in DMEM/F12 containing 10% fetal bovine serum. After the cells reached confluence at Day 7 in culture, SAC gels were digested by collagenase to promote the detachment of RES cell sheets. Then the floating cell sheets were transferred to agarose-coated plates and cultured to form spheroids. The cell sheet shrank and became an aggregated cell mass in a few days; it finally formed a round-shaped spheroid. Diameters of the spheroids were about 516.7 � 28.9 �m at Day 5 after detachment from SAC gels. TUNEL examination of cell viability in the spheroid suggested that no cell was apoptotic until 15 days after cell sheet detachment; TUNEL-positive cells appeared at 20 days. Additionally, no positive staining of proliferating cell nuclear antigen (PCNA) was observed in the spheroids in contrast to strong staining in proliferating monolayer cultured cells. The results of gelatin zymography showed that both matrix metalloproteinases (MMP)-2 and-9 were produced in monolayer culture. However, after the detachment of the cell sheet, the production of both MMPs decreased immediately and could not be detected until 15 days after detachment. In vitro decidualization of the spheroids was induced by arachidonic acid (AA) treatment. RT-PCR analysis showed that typical marker genes for the decidualization, desmin and decidual/trophoblast prolactin-related protein (d/tPRP), were expressed in the spheroids after 2 days of AA treatment, but not in the control groups without treatment. The results of the present study indicate that rat endometrial stromal cells are capable of being regenerated as a spheroid using SAC gels in vitro. Importantly, the present spheroid displays an endometrium-mimicking feature in both structural and functional similarities. The present method is simple and convenient, and therefore provides a new insight into the study of endometrial functions and implantation. This research was supported by a grant from the Ministry of Education, Culture, Sport, Science, and Technology of Japan (Kiban-kenkyu C 18580282).

Impaired clearance of phenacetin in hepatic cirrhosis and fibrosis

OBJECTIVE

CYP450 1A2 is constitutively expressed in liver. Phenacetin O-de-ethylation is a marker reaction for CYP450 1A2 activity. In this paper, the metabolism of phenacetin has been studied in patients with chronic hepatitis B or cirrhosis secondary to a hepatitis B virus infection. The possibility of using the phenacetin test in the evaluation of liver function in these subjects has also been tested.

SUBJECTS AND METHODS

Phenacetin pharmacokinetics and the recovery of its urinary metabolites were studied in 8 normal subjects, 16 patients with chronic hepatitis B and 12 patients with cirrhosis. The phenacetin test was performed in 18 normal subjects and 52 hepatocellular carcinoma (HCC) patients. The test was repeated in HCC patients after treatment with transcatheter arterial chemoembolization (TACE).

RESULTS

Compared with normal controls, phenacetin apparent clearance decreased by 47.0% (p < 0.05) and 78.7% (p < 0.01) in patients with chronic hepatitis B and cirrhosis, respectively. The recovery of phenacetin O-de-ethylated metabolites decreased by 24.6 and 72.4% (p < 0.01). 46 of 52 HCC patients (88.4%) had an abnormal phenacetin test before TACE, where the ratio of plasma total acetaminophen to phenacetin was below the lower limit of the normal control range. The ratio was less than 50% of normal controls in 6 HCC patients who had a deterioration in liver function from Child-Pugh class A to Child-Pugh class B after TACE.

CONCLUSION

The metabolism of phenacetin is impaired in patients with chronic hepatitis B and cirrhosis. The phenacetin test can predict the susceptibility of liver function to TACE in HCC patients.

Roles of mitogen-activated protein kinase pathways during Escherichia coli-induced apoptosis in U937 cells

Escherichia coli (E. coli) infections play an important and growing role in the clinic. In the present study, we investigated the involvement of members of the mitogen-activated protein kinase (MAPK) superfamily, including extracellular signal-regulated kinase (ERK), c-Jun NH(2)-terminal kinase (JNK) and p38 MAPK, and caspase-3 and 9 activity in E. coli-induced apoptosis in human U937 cells. We found that E. coli induces apoptosis in U937 cell lines in a dose- and time-dependent manner, p38 MAPK and JNK were activated after 10 min of infection with E. coli. In contrast, ERK1/2 was down-regulated in a time-dependent manner. The levels of total (phosphorylation state-independent) p38 MAPK, JNK and ERK1/2 did not change in E. coli-infected U937 cells at all times examined. Moreover, exposure of U937 cells to E. coli led to caspase-3 and 9 activity. For the evaluation of the role of MAPKs, PD98059, SB203580 and SP600125 were used as MAPKs inhibitors for ERK1/2, p38 MAPK and JNK. Inhibition of ERK1/2 with PD98059 caused further enhancement in apoptosis and caspase-3 and 9 activity, while a selective p38 MAPK inhibitor, SB203580 and JNK inhibitor, SP600125 significantly inhibited E. coli-induced apoptosis and caspase-3 and 9 activity in U937 cells. The results were further confirmed by the observation that the caspase inhibitors Z-DEVD-FMK and Z-LEHD-FMK blocked E. coli-induced U937 apoptosis. Taken together, we have shown that E. coli increase p38 MAPK and JNK and decrease ERK1/2 phosphorylation and increase caspase-3 and 9 activity in U937 cells.

Screening and characterization of yeasts for xylitol production

AIMS

To discover novel naturally occurring xylitol producing yeast species with potential for industrial applications.

METHODS AND RESULTS

Exactly 274 strains were cultivated on both solid and liquid screening medium with xylose as the sole carbon resource. Five strains were selected on the basis of significant growth and high degree of xylose assimilation. Their phylogenetic position was confirmed by the PCR-RFLP and sequence analysis of the D1/D2 domain of the 5' end of the large subunit rDNA gene (5'-LSU rDNA). Enzymatic analysis was conducted to compare xylose metabolism in each strain. Candida guilliermondii Xu280 and Candida maltosa Xu316 were found to have high xylose consumption rates and xylitol yields in the batch fermentation under micro-aerobic condition. The effect of the different media with high initial xylose concentration on biosynthesis of xylitol by both strains was investigated.

CONCLUSIONS

We have identified Candida spp. strains, which exhibit high levels of xylitol production from xylose suggesting that these may have potential for industrial applications.

SIGNIFICANCE AND IMPACTS OF THE STUDY

Microbial species are of importance for xylitol production. Xylitol production involves complicated metabolic regulation including xylose transport, production of key enzymes and cofactor regeneration. Thus, screening of naturally occurring xylose-utilizing micro-organisms is a viable and effective mean to obtain xylitol producing organisms with industrial application. Moreover, the research on selected strains will contribute to a better understanding of regulatory properties of xylose metabolism in different yeasts.

Cloning and molecular characterization of a gene coding D-xylulokinase (CmXYL3) from Candida maltosa

AIMS

To clone and identify a gene (CmXYL3) coding D-xylulokinase from Candida maltosa Xu316 and understand its physiological function.

METHODS AND RESULTS

Based on the conserved regions of the known D-xylulokinase-encoding genes, a pair of degenerate primers was designed to clone the CmXYL3 gene from C. maltosa Xu316. The coding region and sequences flanking the CmXYL3 gene were obtained by PCR-based DNA walking method. Southern blotting analysis suggested that there is a single copy of the CmXYL3 gene in the genome. The open reading frame starting from ATG and ending with TAG stop codon encoded 616 amino acids with a calculated molecular mass of 68889.743 Da. The CmXYL3 gene under the control of the GPD1 promoter was heterologously expressed in Saccharomyces cerevisiae deficient in D-xylulokinase (deltaScXKS1::LEU2) activity, and restored growth on D-xylulose. The specific activity of D-xylulokinase varied during xylose fermentation and was correlated with aeration level. After growth on different pentoses and pentitols as sole carbon sources, the highest specific activity of D-xylulokinase was observed on D-xylose.

CONCLUSIONS

The CmXYL3 gene isolated from C. maltosa Xu316 encodes a novel D-xylulokinase that plays a pivotal role in xylulose metabolism.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report that describes the isolation and cloning of D-xylulokinase gene (CmXYL3) from C. maltosa Xu316. D-xylulokinase is pivotal for growth and product formation during xylose metabolism. Better understanding of the biochemical properties and the physiological function of D-xylulokinase will contribute to optimizing fermentation conditions and determining the strategies for metabolic engineering of C. maltosa Xu316 for further improvement of xylitol yield and productivity.

Phase I study of ABT-751 in combination with CAPIRI (capecitabine and irinotecan) and bevacizumab in patients with advanced colorectal cancer

13553

Background: ABT-751 (A) is an orally (PO) bioavailable sulfonamide with antimitotic properties. We are performing a non-randomized phase I/II dose-escalation study of A in combination with capecitabine (C), irinotecan (I) and bevacizumab (B) to define the maximum tolerated dose (MTD), dose-limiting toxicity (DLT), and pharmacokinetics (PK) in patients with advanced colorectal cancer (1st or 2nd line). Methods: Patients are treated with A QD for 7d (lead-in) and then begin 21-d cycles of treatment with A (QD) and C (BID) d1–14 PO, I d1 IV, and B d1 IV. Dose escalation started at dose level (DL) 1 at A 150 mg, I 200 mg/m2, and C 1600 mg/m2 (total daily dose) and escalated to full dose CAPIRI (I 250 mg/m2, and C 2000 mg/m2) for DL2. B was then added as standard of care at 7.5 mg/kg for DL2b (and later, DL1b). Blood samples were collected for pharmacogenomics (PG), pharmacodynamics (PD), steady-state PK of A and A metabolites when administered alone or in combination with C, I, and B, and PK of I and I metabolites. Serial dynamic contrast MRI’s, before and after the ABT-751 monotherapy lead-in period, are being performed in a subset of subjects. Results: Eight patients have been treated at dose levels 1 (3), 2 (2), and 2b (3). One patient on DL2 experienced g3 transaminitis and another on DL2b had F&N which were dose-limiting. Dose level 1 is being expanded to 6 patients, now with B (DL1b). Other g3/4 toxicities have included g4 neutropenia (1 subject DL2, 1 DL2b). The formation of A glucuronide appears decreased during combination therapy (see table). I PK, PD, and PG samples were collected and analysis is pending. Of 8 subjects, there have been 4 PD and 4 SD after 2 cycles. Conclusions: The combination therapy of A 150 mg and 20% dose-reduced CAPIRI appears well-tolerated. Patient accrual continues at DL1b. [Table: see text]

No significant financial relationships to disclose.

Extended effects of human papillomavirus 16 E6-specific short hairpin RNA on cervical carcinoma cells

Most cervical carcinomas express high-risk human papillomavirus (HPV) E6 and E7 oncogenes. Small interfering RNA can mediate sequence-specific inhibition of gene expression in mammalian cells. To find a most effective short hairpin RNA (shRNA) for HPV16 E6 messenger RNA (mRNA) and investigate the extended effects of the HPV16 E6 shRNA on cervical carcinoma cells, we stably transfected SiHa cells with four shRNA expression vectors (E6A-D). HPV16 E6A shRNA was found to be the most efficient in our study, which caused the reduction of HPV16 E6 mRNA to 10% in SiHa cells but did not reduce HPV18 E6 mRNA expression in HeLa cells. We subsequently demonstrated that E6A could stably express shRNA and effectively reduce HPV16 E6 and E7 viral genes expression in SiHa cells for more than 4 months. After E6 and E7 repression, there was a dramatic accumulation of p53, p21, and hypophosphorylated pRb proteins in cells. Furthermore, cell proliferation, colony formation ability, tumorigenicity, and in vitro cell invasive capability were suppressed substantially in E6A-transfected cells. These results suggest that the use of shRNA expression vector may be a potential approach for the treatment of persistent HPV infection and HPV-positive cervical carcinoma.

Electrolytic degradation of biorefractory organics and ammonia in leachate from bioreactor landfill

Electrochemical oxidation was applied to treat the effluent from bioreactor landfill with leachate recirculation, characterised as poor biodegradability and high NH3-N concentration. In this study, the effluent was electrolysed in a batch reactor with Ti/TiO2-IrO2-RuO2 anode and stainless steel cathode. The oxidation of dissolved organic matter (DOM) during electrolysis was evaluated based on the evolution of molecular weight grade, hydrophilic fractionation (humic acid, fulvic acid and hydrophilic fractions), specific ultraviolet absorbance (SUVA254) and AOX. The impact of the initial NH3-N concentration on the oxidation was discussed. The results showed that at a current density of 100 mA/cm2, electrolysis time of 1.5 h and electrode gap of 1 cm, NH3-N with an initial concentration of 1.2 g/L could be completely eliminated and 56% of COD with an initial concentration of 1.2 g/L could be removed, which illustrated that the electrolysis-produced chlorine preferentially oxidised ammonia. The electrolysis mainly resulted in the degradation of humic substances and other high molecular DOM, followed by the increase of BOD/COD ratio and decline of SUVA254 of the leachate. The current efficiencies for COD and ammonia oxidation gradually decreased during the electrolysis, with the latter obviously higher than the former. At the optimal electrolysis time of 1.5 h, NH3-N could be totally removed and the BOD/COD ratio could be enhanced to 0.3, which was also favourable to control the AOX at a reasonable level.

Optimum control of the Hemopump as a left-ventricular assist device

A general framework for designing an optimum control strategy for the Hemopump is described. An objective function was defined that includes four membership functions, each constructed based on the desired values of one of the four members: stroke volume, mean left atrial pressure, aortic diastolic pressure and mean pump rotation speed. The Hemopump was allowed to operate either at a constant speed or at two different speeds during a cardiac cycle. The goal was to maximise the objective function by varying the magnitude and timing of the pump speed. Using a canine circulatory model, it was demonstrated that, in general, different cardiac conditions or different clinical objectives require different operation parameters. For example, when a left ventricle with minor ischaemia was simulated, and the main objective was to increase stoke volume, the objective function was maximised, from a value of 0.877 when the pump was off, to 0.946 when the pump was operated at speed 2 (18 500 revolutions min(-1)). On the other hand, for a severely ischaemic heart, the optimum pump speed became speed 3 (20 000 revolutions min(-1)), which maximized the objective function to 0.943 (from 0.707 when the pump was off). The results also suggest that it is more beneficial to operate the Hemopump at two different speeds during a cardiac cycle (a higher speed during systole and early diastole, and a lower speed during late diastole) than to maintain a constant speed throughout the cardiac cycle.

Removal of ocular artifacts from electro-encephalogram by adaptive filtering

The electro-encephalogram (EEG) is useful for clinical diagnosis and in biomedical research. EEG signals, however, especially those recorded from frontal channels, often contain strong electro-oculogram (EOG) artifacts produced by eye movements. Existing regression-based methods for removing EOG artifacts require various procedures for preprocessing and calibration that are inconvenient and time-consuming. The paper describes a method for removing ocular artifacts based on adaptive filtering. The method uses separately recorded vertical EOG and horizontal EOG signals as two reference inputs. Each reference input is first processed by a finite impulse response filter of length M (M = 3 in this application) and then subtracted from the original EEG. The method is implemented by a recursive least-squares algorithm that includes a forgetting factor (lambda = 0.9999 in this application) to track the non-stationary portion of the EOG signals. Results from experimental data demonstrate that the method is easy to implement and stable, converges fast and is suitable for on-line removal of EOG artifacts. The first three coefficients (up to M = 3) were significantly larger than any remaining coefficients.

Conjugation metabolism of acetaminophen and bilirubin in extrahepatic tissues of rats

An anhepatic rat model was used to explore the extrahepatic conjugating metabolism of acetaminophen and serum bilirubin. The recovery of glucuronide- and sulfate-acetaminophen was 47.5% in normal control and 13.4% in model rats in the urine collected for 6 h after administration of acetaminophen 20 mg kg(-1). Following the increase of acetaminophen dose to 150 mg kg(-1), the recovery of urinary glucuronide-acetaminophen increased by 53.9% in normal control; but it decreased by 36.4% in model rats. In contrast to normal control, the pretreatment with phenobarbital did not affect acetaminophen and its metabolite levels in plasma and urine in model rats. After the establishment of anhepatic model the serum direct bilirubin rose dramatically. Urinary bilirubin test was positive in model rats, but not in normal control. No changes were observed in serum total bilirubin and ratio of direct/total bilirubin after the pretreatment with ranitidine or phenobarbital 50 mg kg (-1), i.p. for 5 days in model rats. The results indicate that the glucuronide- and sulfate-acetaminophen formed in the extrahepatic tissues of model rats is 28.2% of normal control, serum free bilirubin can be transformed into conjugated bilirubin in extrahepatic tissues, and the regulation mechanism of phase II conjugating enzymes is different between the hepatic and extrahepatic tissues.