Modelling clogging and biofilm detachment in sponge carrier media

Sponge carrier media provide a large surface area for biofilm support; however, little information is known about how to model their dual nature as a moving bed and as porous media. To investigate the interaction of mass transfer and detachment with bio-clogging, a novel biofilm model framework was built based on individual-based modelling, and hydrodynamics were modelled using the lattice Boltzmann method. The combined model structure enabled the simulation of oxygen and biomass distribution inside the porous network as well as inside the biofilm. In order to apply the model to moving bed biofilm reactors (MBBR), biofilm detachment due to abrasion (carrier collisions) was modelled to be dependent on intracarrier distance. In the initial growth stage, biofilm grew homogeneously on the internal skeleton after which a more discontinuous growth developed which significantly increased permeability. Low detachment rates caused clogging in the outer pores which limited growth of biofilm to the surface region of the sponge. High detachment rates on the surface enabled deeper oxygen penetration with higher internal biomass activity. The degree of clogging was also sensitive to the presence of extracellular polymeric substances because of its large spatial occupancy.

A modified anaerobic digestion process with chemical sludge pre-treatment and its modelling

Activated Sludge Models (ASMs) assume an unbiodegradable organic particulate fraction in the activated sludge, which is derived from the decay of active microorganisms in the sludge and/or introduced from wastewater. In this study, a seasonal change of such activated sludge constituents in a municipal wastewater treatment plant was monitored for 1.5 years. The chemical oxygen demand ratio of the unbiodegradable particulates to the sludge showed a sinusoidal pattern ranging from 40 to 65% along with the change of water temperature in the plant that affected the decay rate. The biogas production in a laboratory-scale anaerobic digestion (AD) process was also affected by the unbiodegradable fraction in the activated sludge fed. Based on the results a chemical pre-treatment using H2O2 was conducted on the digestate to convert the unbiodegradable fraction to a biodegradable one. Once the pre-treated digestate was returned to the digester, the methane conversion increased up to 80% which was about 2.4 times as much as that of the conventional AD process, whilst 96% of volatile solids in the activated sludge was digested. From the experiment, the additional route of the organic conversion processes for the inert fraction at the pre-treatment stage was modelled on the ASM platform with reasonable simulation accuracy.

Tracer experiment and RTD analysis of DAF separator with bar-type baffles

This paper describes the development of a new dissolved air flotation (DAF) separator with a flow streamlining baffle to improve solid separation efficiency. The analysis of the RTD (residence time distribution) curves indicated that the parameter θ(10) (dimensionless time at which 10% of tracer has discharged) increased from 0.38 for control reactor to 0.54 for the test reactor, suggesting significant reduction in short circuit flow. The RTD curves were also used to develop a compartment model for white water (rich in micro-bubbles and water flow is turbulent) and clear water (little or no air content and water flow is quiescent) zones in the reactor using a series of CSTR (continuous stirred tank reactors) and plug flow regime respectively. The proportion of the volume occupied by the white water zone was different in control and test configurations. In the test reactor, the fraction of the clear water zone was found to increase from 6 to 37%, resulting in improvement of the suspended solid (SS) removal efficiency from 97 to 99%.

Efficacy of adjuvant chemotherapy with S-1 in patients with positive peritoneal cytology (CY1) who underwent R1 surgery

84

Background: In recent TNM classification, positive peritoneal cytology (CY1) is regarded as M1 disease and classified into stage IV. However, the prognosis of the CY1 patients underwent R1 surgery (microscopic residual tumor) is considered to be relatively better than those underwent R2 surgery (macroscopic residual tumor). Adjuvant chemotherapy with S-1 had demonstrated significant survival benefit in stage II and III gastric cancer in Japan. However, the efficacy of adjuvant S-1 in patients with relatively more advanced stage had not been investigated. Therefore, we investigated the efficacy of adjuvant chemotherapy with S-1 in CY1 patients underwent R1 surgery.

Methods: Among the 2,202 patients with gastric cancer treated at our department between September 2002 and July 2009, a total of 105 patients with CY1 and underwent R1 surgery were included in this study. Clinocopathological features and survival were retrospectively analyzed using prospectively registered data base system.

Results: There were 64 male and 41 female patients. The median age was 61 years old. Eighty-five patients had T4a or T4b tumor and 96 patients had lymph node metastasis. Seventy-eight patients had undifferentiated type of tumor. In 83 patients, adjuvant chemotherapy with S-1 had been performed. In the uni-variate analysis, only the extent of lymph node dissection (D2) and the adjuvant chemotherapy with S-1 demonstrated significant survival benefit. In multi-variable analysis using Cox proportional hazarded model, N-factor, extent of lymph node dissection (D2 vs D1), and adjuvant chemotherapy with S-1 were selected as independent prognostic factors. The median survival time and 5-year survival rate in patients underwent R1 resection with D2 lymphadenectomy and adjuvant S-1 treatment were 42 months and 46%, respectively.

Conclusions: In patients with CY1 and underwent R1 surgery, adjuvant chemotherapy with S-1 demonstrated significant survival benefit. In patients with positive peritoneal cytology without other non-curative factors, D2 lymph node dissection and adjuvant chemotherapy using S-1 is recommended.

No significant financial relationships to disclose.

Prognostic value of duodenal invasion length in patients with gastric cancer

24

Background: Duodenal invasion (DI) has been considered as a poor prognostic factor of gastric cancer patients. Not all the patients would be able to undergo curative operation. Neoadjuvant chemotherapy (NAC) may improve the rate of curative operation of these patients. In this study, we investigated whether the length of duodenal invasion preoperative diagnosis can be one of factor to decide indication of NAC.

Methods: A total of 118 gastric cancer patients with clinically evident DI, who underwent laparotomy at our center, were enrolled in this study. 42 patients with DI length 20 mm or longer were categorized into long invasion group (LI), 76 patients with DI length shorter than 20 mm were categorized into short invasion group (SI). Clinicopathologic features, rate of direct invasion and lymph nodes involvement, R0 resection, and survival rate were compared between two groups.

Results: Resection rate was significantly different between two groups: SI group (85.5%; 65/76), LI group (69.0%; 29/42). Direct invasion to adjacent organs was significantly more frequently observed in LI group (21%; 6/29) than SI group (4 %; 3/65, p = 0.02). In LI group, pancreas invasion was observed in all patients except for one patient. Multivariate analysis to predict the adjacent organ invasion revealed that CT diagnosis (p = 0.005) and invasion length (p = 0.01) were selected as risk factors of direct invasion to adjacent organs. There was no significant difference of nodal involvement between LI group (83%; 24/29) and SI group (83%; 54/65 p = 0.99). The 5-year survival rate was 19% in LI group and 43% in SI group (p = 0.23). The number of patients who underwent R0 resection was more frequently in SI group (75.4%; 49/65) than SI group (69.1%; 16/29). The factors of R1 or R2 resection were metastasis of peritoneum or direct invasion to adjacent organs.

Conclusions: In patients with long duodenal invasion, direct invasion to the pancreas was more frequently observed, and resulted in low curative resection rate and poor survival. Preoperative chemotherapy may improve the curative resection rate and survival in these patients. Prospective study is warranted to evaluate the efficacy of NAC for these patients.

No significant financial relationships to disclose.

Sorption and diffusion of Eu in sedimentary rock in the presence of humic substance

Sorption and diffusion behaviors of Eu in sedimentary rock in the presence of humic substance were investigated. The sedimentary rock collected from 500 m depth of HDB-6 bore hole at horonobe URL site of Japan and Aldrich humic acid (HA) were used in the present study. Sorption behaviors of Eu and the HA on the sedimentary rocks with and without the rock organic matter (ROM) were elucidated as a function of HA concentration. The HA reduced the sorption of Eu on the rock with the increase of HA. Eu and HA sorption on the rock with the ROM was larger than on the rock after removing the ROM, indicating that the ROM plays an important role on the sorption of Eu and HA. The diffusion of Eu in the presence of HA was examined as a function of HA concentration and molecular weight of the HA (∼150 kDa or below 10 kDa) by means of a reservoir depletion test method with the intact rock core of the sedimentary rock. Depletion of Eu concentration in the reservoir was reduced with the increase of HA concentration. On the other hand, slight depletion of HA concentration in the reservoir was observed, indicating that the larger HA molecule diffused less into the rock. From the depletion curve and in-diffusion profile of Eu in the rock, the effective diffusion coefficient, D e, and distribution coefficient, K d, in the intact system were estimated based on the profile fitting of the diffusion data with the conventional simple diffusion-sorption model. It was elucidated that the HA reduced the K d and D e of Eu in the intact system with the increase of HA. The contribution of the HA with smaller molecular weight to both the Eu sorption and diffusion was examined.

Feasibility study of adjuvant chemotherapy with S-1 plus cisplatin for gastric cancer

PURPOSE

To evaluate the feasibility of S-1 plus cisplatin as adjuvant chemotherapy for stage III gastric cancer after curative resection.

METHODS

Japanese patients with stage III gastric cancer who underwent gastrectomy with D2 lymph node resection were enrolled. Treatment consisted of 3 cycles of S-1 (80 mg/m(2)/day, b.i.d.) for 21 days followed by a 14-day rest, and cisplatin (60 mg/m(2) iv) on day 8. After that, S-1 monotherapy was given on days 1-28 every 6 weeks until 1-year postsurgery. After protocol amendment, the first chemotherapy cycle consisted of S-1 monotherapy; cisplatin was added to cycles 2, 3, and 4, followed by S-1 monotherapy up to 1-year postsurgery. The primary endpoint was the completion rate of three cycles of S-1 plus cisplatin.

RESULTS

A total of 63 enrolled patients have been evaluated. Grade 3/4 toxicities included neutropenia (40%), anorexia (28%), and febrile neutropenia (4%) before protocol amendment (n = 25), and neutropenia (37%), anorexia (8%), and febrile neutropenia (3%) after amendment implementation (n = 38). Excluding ineligible cases, treatment completion rates were 57% (12/21) before and 81% (30/37) after the protocol amendment.

CONCLUSIONS

The amended S-1 plus cisplatin is more feasible than the original protocol because of early dose reduction of S-1 prior to cisplatin addition and greater recovery time from surgery prior to cisplatin. This treatment should be considered as a feasible experimental arm for the next postoperative adjuvant phase III trial.

Phase I clinical and biomarker study of BIBF 1120, an oral multitarget tyrosine kinase inhibitor, in patients with advanced solid tumors (ST): Impact of CD133- and CD117-positive cells on a biomarker of an antiangiogenic inhibitor

3572

Background: BIBF 1120 (Vargatef) is an orally bioavailable small molecule inhibitor of multiple receptor tyrosine kinases, including vascular endothelial growth factor receptors, fibroblast growth factor receptors and platelet-derived growth factor receptors. Methods: BIBF 1120 (150–250 mg) was administered orally twice-daily (bid) to heavily pre-treated solid tumor (ST) patients to determine safety, tolerability, maximum tolerated dose (MTD) and pharmacokinetics (PK). CD133- and/or CD117 (c-kit)-positive cells from CD34+CD45dim peripheral blood cells were evaluated using flow-cytometry on pre-treatment, Day 2, Day 8 and Day 29. Results: Twenty-one patients were treated at doses of 150 mg bid (n=3), 200 mg bid (n=12) and 250 mg bid (n=6). Dose-limiting toxicities (DLTs) of reversible Grade 3/4 elevated liver enzymes occurred in three of 12 patients at 200 mg bid and three of six patients at 250 mg bid; 200 mg bid was declared as the MTD. Best observed responses were stable disease in 16 (76.2%) patients and median progression-free survival was 113 days (95% CI: 77–119 days). PK analysis indicated that Cmax and AUC increased with increased dose within the dose range tested. Flow cytometry analysis revealed that BIBF 1120 treatment significantly increased the percentage of CD133+CD117- cells (p<0.001) on Day 29 compared with pre-treatment, and conversely decreased that of CD133-CD117+ cells (p<0.01). In addition, CD133+CD117+ cells tended to decrease in responders (stable disease) to a greater extent than in non- responders after treatment. Conclusions: BIBF 1120 dosed continuously at 200 mg bid was well tolerated and appeared to provide some clinical benefit. Our biomarker study provides a novel insight into CD133- and CD117-positive cells as a pharmacodynamic biomarker for an antiangiogenic inhibitor.

[Table: see text]

Phase I study of sunitinib (SU) in combination with pemetrexed (Pem) in patients (pts) with advanced solid tumors (ST)

e14630

Background: SU is an oral, multitargeted tyrosine kinase inhibitor of VEGFRs, PDGFRs, KIT, RET, FLT3, and CSR-1, and shows antitumor activities in several types of solid malignancies. Non-small-cell lung cancer (NSCLC) xenograft data indicate SU enhanced the antitumor activity of Pem. This phase I study was designed to evaluate the safety, tolerability, and pharmacokinetics (PK) of combination therapy with the oral SU and Pem for Japanese patients with advanced ST. Methods: Pts with ST refractory to standard therapy were randomly assigned to receive either oral SU 50 mg/day for 2 weeks followed by 1 week rest (Schedule 2/1, S-2/1) or SU 37.5 mg continuous daily dose (CDD). Fixed-dose Pem (500mg/m2 IV) was administered on day1 every 21 days. A standard “3+3” design was employed in both treatment schedules and treatment continued until tumor progression or dose-limiting toxicity (DLT) was observed. Results: A total of 12 pts (med. age 63 years, range 49–69; 10 Male/ 2 Female) have been enrolled (6 pts in the S-2/1 arm and 6 pts in the CDD arm). The most common cancer is NSCLC (9 pts, 75%). All patients completed their first cycle for DLT evaluation, and no DLTs were observed in either treatment arm. The most common toxicities were fatigue (n=8), anorexia (n=6), and thrombocytopenia (n=12). Treatment-related ≥ grade 3 adverse events (AEs) included fatigue (n=1), hypertension (n=1), neutropenia (n=4), leucopenia (n=3), thrombocytopenia (n=2), lymphopenia (n=2), and increased ALT (n=1). Three pts (S-2/1: 2, CDD: 1) required dose reduction of SU due to G3 toxicities. All toxicities were clinically manageable and reversible. One pt with NSCLC had a documented PR with cavity formation inside the tumor. Conclusions: SU 37.5 mg/day (CDD schedule) plus Pem 500mg/m2 every 21 days, and SU 50 mg/day (S-2/1 schedule) plus Pem 500mg/m2 every 21 days were well tolerated and associated with encouraging antitumor activity.

[Table: see text]

Prospective multicenter trial of sentinel node mapping for gastric cancer

4518

Background: The sentinel node (SN) concept has revolutionized the approach to the surgical staging of both melanoma and breast cancer, and these techniques can yield patient benefit by avoiding various complications due to unnecessary prophylactic regional lymph node dissection in cases with negative SN for cancer metastasis. Clinical application of SN mapping for early gastric cancer had been controversial for years. However, single institutional results of SN mapping for early gastric cancer are almost acceptable results in terms of detection rate and accuracy to determine lymph node status. We hypothesized that SN mapping plays a key role to obtain individual information and allows modification of the surgical procedure for early gastric cancer. Methods: The Japan Society of Sentinel Node Navigation Surgery (JSNNS) has conducted a prospective multicenter trial of SN mapping by a dual tracer method with radioactive colloid and blue dye. Between September 2004 and March 2008, 433 patients with early gastric cancer were accrued at 12 comprehensive hospitals. Patients were enrolled under JSNNS and each institutional review board-approved protocols. Eligibility criteria were that patients had clinically T1N0M0 or T2N0M0 single tumor with diameter of primary lesion less than 4cm without any previous treatments. Technetium-99m tin colloid and isosulfan blue were utilized as dual tracers for SN mapping. Results: SN mapping has been performed for 397 patients with early gastric cancer. Detection rate of hot and/or blue node using our procedure was 97.5% (387/397). The mean number of sentinel nodes per case was 5.6. Fifty-three of 57 cases with lymph node metastasis showed positive sentinel nodes. The sensitivity to detect metastasis based on SN status was therefore 93% in our experience. Accuracy of metastatic status based on SN was 99% (383/387). In two of the four SN false-negative cases, the tumor involved to pT2, and only one case showed the metastatic lymph node beyond the SN basin. Conclusions: Our results suggest that SN concept for clinically N0 early gastric cancer could be validated, and minimized gastrectomy with individualized selective and modified lymphadenectomy for early gastric cancer with negative SN should become feasible and clinically useful as less invasive surgical procedures.

No significant financial relationships to disclose.

Chemokine-like factor expression in the idiopathic inflammatory myopathies

OBJECTIVES

We evaluated the expression of chemokine-like factor (CKLF) in biopsied muscle fibers in inflammatory myopathies, non-inflammatory myopathies and neurologically diseased controls.

MATERIALS AND METHODS

We studied the expression of CKLF in 15 polymyositis (PM), five dermatomyositis (DM), 15 non-inflammatory myopathies and nine neurologically diseased patients by immunohistochemistry.

RESULTS

Chemokine-like factor was mostly expressed in small diameter muscle fibers surrounded by infiltrated lymphocytes of inflammatory myopathies patients. Parts of them were also positive for the staining of the developmental form of myosin heavy chain, a maker of regenerating muscle fibers. Thrombin immunoreactivity was observed in endomysium in PM and perimysium in DM. In vitro differentiation study showed a constitutive expression of CKLF in myoblasts that was abolished in myotubes during differentiation process and was induced again by thrombin. Thrombin regulates CKLF expression through protease-activated receptor-1 in myotubes. Treatment of a protein kinase C inhibitor partially blocked CKLF expression in myoblasts, while it remarkably inhibited that in myotubes.

CONCLUSION

Chemokine-like factor expression is differentially regulated in myoblasts and myotubes. Thrombin could be a strong regulator for its expression. As CKLF is immunohistochemically positive in regenerating muscle fibers, we postulate here that CKLF is a useful marker for regenerating muscle fibers in inflammatory myopathies.