Modelling and simulation revealing mechanisms likely responsible for achieving the nitrite pathway through aeration control

Nitrogen removal via nitrite has recently gained a lot of interest because it results in significant savings in both aeration costs and COD (chemical oxygen demand) requirements for denitrification, when compared to the conventional biological nitrogen removal via nitrate. The effectiveness of two different control strategies to achieve the nitrite pathway in systems with sludge retention has been experimentally demonstrated: (i) control of aerobic phase length, with which aeration is terminated as soon as ammonia is completely oxidised; (ii) operation at low DO setpoints in the aerobic phase. These strategies have been extensively studied in nitrifying reactors and are currently applied in real systems achieving biological carbon, nitrogen and phosphorus removal. In this work, we aim to demonstrate, through modelling and simulation, that the competition between nitrite reducers and nitrite oxidisers for nitrite, rather than kinetic selection plays a major role in NOB washout. Moreover, the results show that the occurrence of simultaneous nitrification and denitrification under "aerobic" conditions is very helpful for the nitrite pathway obtainment and for a more efficient COD utilisation.

Repeated Intrathecal Administration of Ropivacaine Causes Neurotoxicity in Rats

Previous studies suggest that ropivacaine causes the least neurotoxicity among local anaesthetics. Most data derive from a single injection of ropivacaine into the subarachnoid space. The histological changes and behavioural effects of repeated intrathecal administration have yet to be studied. We examined the possible neurotoxicity of multiple doses of intrathecal ropivacaine in rats.

Rats received 0.12 ml/kg body weight ropivacaine in normal saline at concentrations of 0.25%, 0.5%, 0.75% and 1.0% at 90-minute intervals via an implanted intrathecal catheter (ID 0.12 mm, OD 0.35 mm) for 48 hours. At L3, the spinal cord and posterior roots were examined by light and electron microscopy. We performed in situ TUNEL assay to evaluate apoptosis in the spinal cord. Sensory threshold to noxious stimulation along with behavioural change were also studied.

Both 0.75% and 1.0% ropivacaine induced neuronal injury characterised by infiltration of inflammatory cells, vacuolation of myelin sheaths and axons, abnormal morphology of neurons and apoptosis in the spinal cord, mainly in posterior roots and the adjacent posterior white matter. Compared to controls, the percentage of maximum possible effect did not show any significant differences between the rats treated with variable concentrations of ropivacaine or tested with either heat or mechanical stimulation. As expected, the recovery time to normal ambulation was prolonged as the ropivacaine concentration was increased.

Ropivacaine can induce neurotoxicity and trigger apoptosis in a dose-dependent manner after repeated intrathecal administration. Although the clinical safety profile of ropivacaine appears favourable compared with other local anaesthetics, it is possible our findings have clinical significance.

Immobilization of Alcaligenes faecalis penicillin G acylase on epoxy-type supports

Alcaligenes faecalis penicillin G acylase has several desired features over other penicillin G acylases and its use in industry requires immobilization. In this work, two novel supports ZH-EP (epoxy-type) and ZH-HA (epoxy-amino type) were used to immobilize Alcaligenes faecalis penicillin G acylase (AfPGA) with Eupergit C as reference. The saturation of immobilized protein on ZH-EP (269 mg/g, 116 h) and ZH-HA (296 mg/g, 15 h) was obtained more rapidly than Eupergit C (197 mg/g, 260 h). And the activity of immobilized AfPGA on ZH-EP (520 U/g) and ZH-HA (2200 U/g) was higher than that on Eupergit C (310 U/g). The properties of three immobilized enzymes were compared and no obvious difference was observed, which indicated that ZH-EP and ZH-HA were promised in industry.

An improved model averaging scheme for logistic regression

Recently, penalized regression methods have attracted much attention in the statistical literature. In this article, we argue that such methods can be improved for the purposes of prediction by utilizing model averaging ideas. We propose a new algorithm that combines penalized regression with model averaging for improved prediction. We also discuss the issue of model selection versus model averaging and propose a diagnostic based on the notion of generalized degrees of freedom. The proposed methods are studied using both simulated and real data.

Impact of nitrate addition on biofilm properties and activities in rising main sewers

Anaerobic sewer biofilm is a composite of many different microbial populations, including sulfate reducing bacteria (SRB), methanogens and heterotrophic bacteria. Nitrate addition to sewers in an attempt to control hydrogen sulfide concentrations affects the behaviour of these populations, which in turn impacts on wastewater characteristics. Experiments were carried out on a laboratory reactor system simulating a rising main to determine the impact of nitrate addition on the microbial activities of anaerobic sewer biofilm. Nitrate was added to the start of the rising main during sewage pump cycles at a concentration of 30 mg-N L(-1) for over 5 months. While it reduced sulfide levels at the outlet of the system by 66%, nitrate was not toxic or inhibitory to SRB activity and did not affect the dominant SRB populations in the biofilm. Long-term nitrate addition in fact stimulated additional SRB activity in downstream biofilm. Nitrate addition also stimulated the activity of nitrate reducing, sulfide oxidizing bacteria that appeared to be primarily responsible for the prevention of sulfide build up in the wastewater in the presence of nitrate. A short adaptation period of three to four nitrate exposure events (approximately 10 h) was required to stimulate biological sulfide oxidation, beyond which no sulfide accumulation was observed under anoxic conditions. Nitrate addition effectively controlled methane concentrations in the wastewater. The nitrate uptake rate of the biofilm increased with repeated exposure to nitrate, which in turn increased the consumption of biodegradable COD in the wastewater. These results provide a comprehensive understanding of the impact of nitrate addition on wastewater composition and sewer biofilm microbial activities, which will facilitate optimization of nitrate dosing for effective sulfide control in rising main sewers.

A muscle-targeting peptide displayed on AAV2 improves muscle tropism on systemic delivery

Adeno-associated virus (AAV) has become a leading gene transfer vector for striated muscles. However, the AAV vectors also exhibit broad tropisms after systemic delivery. In an attempt to improve muscle tropism, we inserted a 7-amino-acid (ASSLNIA) muscle-targeting peptide (MTP) in the capsids of AAV2 at residue 587 or 588, generating AAV₅₈₇MTP and AAV₅₈₈MTP. In vitro studies showed that both viruses diminished their infectivity on non-muscle cell lines as well as on un-differentiated myoblasts, however, preserved or enhanced their infectivity on differentiated myotubes. AAV₅₈₇MTP, but not AAV₅₈₈MTP, also abolished its heparin-binding capacity and infected myotubes in a heparin-independent manner. Furthermore, in vivo studies by intravenous vector administration in mice showed that AAV₅₈₇MTP enhanced its tropism to various muscles and particularly to the heart (24.3 fold of unmodified AAV2), whereas reduced its tropism to the non-muscle tissues such as the liver, lungs and spleen, etc. This alteration of tissue tropism is not simply due to the loss of heparin-binding, since a mutant AAV2 (AAVHBSMut) containing heparin-binding site mutations lost infectivity on both non-muscle and muscle cells. Furthermore, free MTP peptide, but not the scrambled control peptide, competitively inhibited AAV₅₈₇MTP infection on myotubes. These results suggest that AAV2 could be re-targeted to the striated muscles by a muscle-targeting peptide inserted after residue 587 of the capsids. This proof of principle study showed first evidence of peptide-directed muscle targeting upon systemic administration of AAV vectors.

Impact of pegylated liposomal doxorubicin (PLD) plus docetaxel (D) versus single-agent D on health-related quality of life (HRQOL) of patients with advanced breast cancer (BC) previously treated with neoadjuvant-adjuvant anthracycline

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Background: A randomized, multicenter phase 3 trial of PLD+D showed a significant improvement in the primary endpoint of time to progression (TTP) compared with D alone but with increased Grade 3/4 hand-foot syndrome (HFS: 24% vs. 0%) and mucositis/stomatitis (M/S: 12% vs. 1%) in patients (pts) with advanced breast cancer (BC). (Sparano JA et al. SABCS 2008. #80) This analysis evaluated HRQOL in these pts. Methods: Pts were randomized to D 75 mg/m2 (N=373) or PLD 30 mg/m2 + D 60 mg/m2 (N=378) on Day 1 every 21 days until progression or unacceptable toxicity. HRQOL was assessed using the Functional Assessment of Cancer Therapy - Breast (FACT-B) at baseline and at every cycle during treatment. FACT-B has 4 primary domains: physical, social/family, emotional, and functional, plus a BC-specific subscale. The primary analysis was a t-test comparison of change in the trial outcome index (TOI) from baseline to the last evaluation. TOI combined physical/functional domain scores with BC-specific scores. Other FACT-B endpoints analyzed included FACT-B total score and individual subscales. Also, % pts meeting an established minimally important difference (MID) of HRQOL improvement in TOI was assessed. Results: Median number of cycles was 6 for both arms. TOI was available for 97.9% of all scheduled assessments for both treatment groups. At baseline, mean FACT-B and TOI scores were similar for PLD+D vs D arms (94.2±18.6 vs 95.3±18.7 and 59.7±13.8 vs 60.2±13.4, respectively); other FACT-B domains were also similar. PLD+D vs D arms showed similar mean change from baseline to last evaluation in TOI (-4.6±12.2 vs -6.0±12.4; P=0.13). Other FACT-B subscales showed 1–2 point differences across domains over time. Likewise, % pts reaching MID was similar across arms. Pts in both arms experienced similar FACT-B declines as disease progressed. Conclusions: Despite increased HFS and M/S with PLD+D vs D alone, HRQOL was comparable for both arms.

[Table: see text]

Modelling using rRNA-structured biomass models

Models currently used have been developed to describe the storage response in the activated sludge process. In these models the distribution of the substrate flux between growth and storage is an empirical function. rRNA-structured biomass models are proposed to describe the metabolic status of cells in view of predicting the growth response (dmicro/dt) of cells in activated sludge process. The autocatalytic reaction rate of the synthesis of the PSS component (rRNA) can provide a mechanistic explanation for the growth response and the growth lag phase. The proposed models were able to describe and predict properly the growth response of the biomass in various types of reactor. Such models could be more widely applicable by using intrinsic model parameters. This would be a key improvement for as it would lead to improved models for design.

Cohort differences in the progression of developmental pathways: evidence for period effects on secular trends of violence in males

BACKGROUND

Rates of violence in the USA have fluctuated widely over the past few decades. Theorists have examined period and cohort effects, but there appear to be no studies examining these effects on progression in developmental pathways towards violence.

OBJECTIVE

To assess whether differences in progression among individuals in the Pittsburgh Youth Study are consistent with period or cohort effects.

DESIGN

Multivariate logistic regression was conducted to examine differences between cohorts in the odds of progressing through the developmental pathway towards violence. Adjusted and unadjusted odds ratios (ORs) and corresponding 95% CI are reported.

SETTING

Pittsburgh Pennsylvania, from 1987 to 2000.

SUBJECTS

Two cohorts of male adolescents from the Pittsburgh Youth Study. The youngest cohort (n = 503) was followed from median ages 7 to 20, and the oldest cohort (n = 506) was followed up from median ages 13 to 25.

MAIN OUTCOME MEASURE

The odds of progression along a developmental pathway towards violence.

RESULTS

There was no statistically significant difference between the cohorts in progression from minor aggression to physical fighting (OR = 1.13, 95% CI 0.77 to 1.65). However, after adjustment for major risk factors, the oldest cohort was significantly more likely to progress from physical fighting to violence (OR = 2.34, 95% CI 1.39 to 3.92).

CONCLUSIONS

These results provide initial evidence that cohort effects, which would be present early in development, do not contribute significantly to later differences in reported violence and raises the possibility of whether period effects can explain these differences.

Nitrite effectively inhibits sulfide and methane production in a laboratory scale sewer reactor

The production and emission of hydrogen sulfide and methane by anaerobic microoganisms in sewer systems is a well-documented problem. The effectiveness of nitrite in controlling sulfide and methane production was tested in a laboratory scale sewer reactor. Nitrite was continuously dosed in the reactor for 25 days at concentrations of 20-140mgN/L. No sulfide and methane accumulation was observed in the reactor in the presence of nitrite. A significant reduction was observed in the sulfate reduction and methane production capabilities of the biofilm. Nitrite also stimulated biological sulfide oxidation within the biofilm. The nitrite uptake rate of the reactor increased over the nitrite dosing period and nitrous oxide production was observed within the biofilm. When nitrite addition was stopped, sulfate reduction and methane production gradually resumed, and reached pre-nitrite addition levels after 2.5 months. The slow recovery suggests that nitrite can be applied intermittently for sulfide and methane control, which represents a key advantage over similar chemicals such as nitrate and oxygen. The study demonstrates nitrite addition as a promising and effective strategy for the management of sulfide and methane in sewers. Further investigation and optimization are still required before application in the field.

Torsional ultrasound modality for hard nucleus phacoemulsification cataract extraction

AIM

To evaluate the efficacy and safety of phacoemulsification using torsional modality with different parameter settings for hard nucleus cataract extraction.

DESIGN

A prospective, randomised clinical study.

METHODS

A clinical practice study conducted at the Cataract Service, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, and Guangzhou. One eye each from 198 consecutive patients with cataract density grade IV according to the Emery-Little system classification system, requiring phacoemulsification and intraocular lens implantation, was included. Eyes were randomly assigned to the Linear Torsional combined with Ultrasound power group (Linear Tor+US group, n = 66), 100% Fixed Torsional group (Fixed Tor group, n = 65) and conventional Ultrasound burst group (US group, n = 67). All surgeries were performed by a single experienced surgeon and outcomes evaluated by another surgeon masked to treatment. Intraoperative parameters were Ultrasound Time (UST), Cumulative Dissipated Energy (CDE) and surgical complications. Patients were examined on post-op days 1, 7 and 30. Postoperative outcomes were final best corrected visual acuity (BCVA), average central and incisional corneal thickness and central endothelial cell counts.

RESULTS

The mean UST was lower in the Fixed Tor group than in the US group and in the Lin US+Tor group (p0.01), greater average central corneal and incisional thickness on days 1, 7 (p0.01), and higher average corneal endothelial cell losses on day 7 and 30 days (p

CONCLUSIONS

Torsional combined with ultrasound power or high fixed torsional amplitude can yield more effective hard nucleus phacoemulsification than conventional ultrasound modality.

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MESH Headings

• Aged
• Aged, 80 and over
• Cornea/pathology
• Endothelium, Corneal/pathology
• Female
• Humans
• Lens Nucleus, Crystalline/surgery
• Male
• Middle Aged
• Phacoemulsification/methods
• Prospective Studies
• Tomography, Optical Coherence
• Treatment Outcome
• Ultrasonic Therapy/methods
• Visual Acuity

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A phase I study of the safety and pharmacokinetics of trabectedin in combination with pegylated liposomal doxorubicin in patients with advanced malignancies

BACKGROUND

To determine the maximum tolerated dose (MTD), safety, potential pharmacokinetic (PK) interactions, and effect on liver histology of trabectedin in combination with pegylated liposomal doxorubicin (PLD) for advanced malignancies.

PATIENTS AND METHODS

Entry criteria for the 36 patients included normal liver function, prior doxorubicin exposure <250 mg/m(2), and normal cardiac function. A 1-h PLD (30 mg/m(2)) infusion was followed immediately by one of six trabectedin doses (0.4, 0.6, 0.75, 0.9, 1.1, and 1.3 mg/m(2)) infused over 3 h, repeated every 21 days until evidence of complete response (CR), disease progression, or unacceptable toxicity. Plasma samples were obtained to assess PK profiles.

RESULTS

The MTD of trabectedin was 1.1 mg/m(2). Drug-related grade 3 and 4 toxic effects were neutropenia (31%) and elevated transaminases (31%). Six patients responded (one CR, five partial responses), with an overall response rate of 16.7%, and 14 had stable disease (less than a 50% reduction and less than a 25% increase in the sum of the products of two perpendicular diameters of all measured lesions and the appearance of no new lesions) >4 months (39%). Neither drug had its PK affected significantly by concomitant administration compared with trabectedin and PLD each given as a single agent.

CONCLUSION

Trabectedin combined with PLD is generally well tolerated at therapeutic doses of both drugs in pretreated patients with diverse tumor types and appears to provide clinical benefit. These results support the need for additional studies of this combination in appropriate cancer types.

Characterizing the biochemical activity of full-scale enhanced biological phosphorus removal systems: A comparison with metabolic models

The metabolism of polyphosphate accumulating organisms (PAOs) has been widely studied through the use of lab-scale enrichments. Various metabolic models have been formulated, based on the results from lab-scale experiments using enriched PAO cultures. A comparison between the anaerobic stoichiometry predicted by metabolic models with that exhibited by full-scale sludge in enhanced biological phosphorus removal (EBPR) wastewater treatment plants (WWTPs) was performed in this study. Batch experiments were carried out with either acetate or propionate as the sole carbon source, using sludges from two different EBPR-WWTPs in Australia that achieved different phosphorus removal performances. The results support the hypothesis that the anaerobic degradation of glycogen is the primary source of reducing equivalents generated by PAOs, however, they also suggested a partial contribution of the tricarboxylic acid (TCA) cycle in some cases. The experimental results obtained when acetate was the carbon source suggest the involvement of the modified succinate-propionate pathway for the generation of poly-beta-hydroxyvalerate (PHV). Overall, the batch test results obtained from full-scale EBPR sludge with both substrates were generally well described by metabolic model predictions for PAOs.

Continuous measurement of dissolved sulfide in sewer systems

Sulfides are particularly problematic in the sewage industry. Hydrogen sulfide causes corrosion of concrete infrastructure, is dangerous at high concentrations and is foul smelling at low concentrations. Despite the importance of sulfide monitoring there is no commercially available system to quantify sulfide in waste water. In this article we report on our use of an in situ spectrometer to quantify bisulfide in waste water and additional analysis with a pH probe to calculate total dissolved sulfide. Our results show it is possible to use existing commercially available and field proven sensors to measure sulfide to mg/l levels continuously with little operator intervention and no sample preparation.

Vaccination of sarcoid-bearing donkeys with chimeric virus-like particles of bovine papillomavirus type 1

Equine sarcoids are fibroblastic skin tumours affecting equids worldwide. While the pathogenesis is not entirely understood, infection with bovine papillomavirus (BPV) type 1 (and less commonly type 2) has been implicated as a major factor in the disease process. Sarcoids very seldom regress and in fact often recrudesce following therapy. Nothing is known about the immune response of the equine host to BPV. Given that the viral genes are expressed in sarcoids, it is reasonable to assume that vaccination of animals against the expressed viral proteins would lead to the induction of an immune response against the antigens and possible tumour rejection. To this end we vaccinated sarcoid-bearing donkeys in a placebo-controlled trial using chimeric virus-like particles (CVLPs) comprising BPV-1 L1 and E7 proteins. The results show a tendency towards enhanced tumour regression and reduced progression in the vaccinated group compared to control animals. Although promising, further studies are required with larger animal groups to definitely conclude that vaccination with CVLPs is a potential therapy for the induction of sarcoid regression.

Activating transcription factor 3 up-regulated by c-Jun NH(2)-terminal kinase/c-Jun contributes to apoptosis induced by potassium deprivation in cerebellar granule neurons

Cerebellar granule neurons (CGNs) depend on potassium depolarization for survival and undergo apoptosis when deprived of depolarizing concentration of potassium. Activating transcription factor 3 (ATF3), a stress-inducible protein, belongs to the ATF/CREB family of transcription factors family and is involved in cell growth and apoptosis. However, the role of ATF3 in neuronal apoptosis remains unknown. Here, we showed that ATF3 was up-regulated under potassium deprivation in CGNs, and this induction was preceded by a rapid and sustained activation of c-Jun NH(2)-terminal kinase/c-Jun signaling pathway, which plays a fundamental role in neuronal apoptosis. Furthermore, ATF3 up-regulation was abolished by inhibition of JNK or knockdown of c-Jun. Finally, knockdown of ATF3 by RNA interference protected CGNs from potassium deprivation-induced apoptosis. Taken together, our results indicate that ATF3 is a downstream target of JNK/c-Jun pathway and contributes to apoptosis induced by potassium deprivation in rat CGNs.

Prediction of the hip joint centre in adults, children, and patients with cerebral palsy based on magnetic resonance imaging

The location of the hip joint centre (HJC) is required for calculations of hip moments, the location and orientation of the femur, and muscle lengths and lever arms. In clinical gait analysis, the HJC is normally estimated using regression equations based on normative data obtained from adult populations. There is limited relevant anthropometric data available for children, despite the fact that clinical gait analysis is predominantly used for the assessment of children with cerebral palsy. In this study, pelvic MRI scans were taken of eight adults (ages 23-40), 14 healthy children (ages 5-13) and 10 children with spastic diplegic cerebral palsy (ages 6-13). Relevant anatomical landmarks were located in the scans, and the HJC location in pelvic coordinates was found by fitting a sphere to points identified on the femoral head. The predictions of three common regression equations for HJC location were compared to those found directly from MRI. Maximum absolute errors of 31 mm were found in adults, 26 mm in children, and 31 mm in the cerebral palsy group. Results from regression analysis and leave-one-out cross-validation techniques on the MRI data suggested that the best predictors of HJC location were: pelvic depth for the antero-posterior direction; pelvic width and leg length for the supero-inferior direction; and pelvic depth and pelvic width for the medio-lateral direction. For single-variable regression, the exclusion of leg length and pelvic depth from the latter two regression equations is proposed. Regression equations could be generalised across adults, children and the cerebral palsy group.

Free ammonia and free nitrous acid inhibition on the anabolic and catabolic processes of Nitrosomonas and Nitrobacter

The inhibitory effects of free ammonia (FA) and free nitrous acid (FNA) on the catabolic and anabolic processes of Nitrosomonas and Nitrobacter were investigated using a method that allows decoupling the growth and energy generation processes. Lab-scale sequencing batch reactors (SBRs) were operated for the enrichment of Nitrosomonas and Nitrobacter. Fluorescent In-Situ Hybridization (FISH) analysis showed that the reactors were 82% and 73% enriched with Nitrosomonas and Nitrobacter, respectively. Batch tests were carried out to measure the oxygen uptake rate (OUR) by the enriched cultures at various FA and FNA levels, in the presence (OUR with CO2 ) or absence (OUR without CO2) of inorganic carbon (CO2, HCO*3 and CO 2*3). FA up to 16.0 mgNH3-N.L(-1) was not found to have any inhibitory effect on either the catabolic or anabolic processes of the Nitrosomonas culture, but both these processes were inhibited by FNA. While an FNA level of 0.40-0.63 mgHNO2-N.L(-1) inhibited the energy production capability of Nitrosomonas by 50%, the growth process of the culture was completely inhibited by FNA at a concentration of 0.40 mgHNO2-N.L(-1). Both FA and FNA were found to have strong inhibition on the anabolic processes of Nitrobacter, but with limited inhibitory effects on the catabolism of this culture. The biosynthesis of Nitrobacter was totally inhibited at an FA level of 6.0 mgNH3-N.L(-1) (or above) or an FNA level of 0.02 mgHNO2-N.L(-1) (or above). At the same level of FA, the energy production capability of Nitrobacter was only inhibited by 12%, whereas an FNA level of up to 0.024 mgHNO2-N.L(-1) did not show any inhibition on the energy production of Nitrobacter. Further, these inhibitory effects appears to be much stronger on Nitrobacter than on Nitrosomonas, supporting that FA and FNA inhibition may play a major role in the elimination of nitrite oxidizing bacteria in processes treating wastewater containing a high level of nitrogen.

A rapid reverse transcription-PCR assay for F+ RNA coliphages to trace fecal pollution in Table Rock Lake on the Arkansas-Missouri border

Source determination of fecal contamination is imperative to efficiently reduce the fecal material load to environmental waters. This study developed primer pairs targeting three F+ RNA bacteriophages and a simple filtration sampling method to enumerate and identify coliphages in environmental waters. Water samples were collected seasonally for one year from the watershed of Table Rock Lake on the Arkansas-Missouri border in areas predisposed to fecal contamination. Collected samples were analyzed quantitatively with most probable number and plaque assays and qualitatively with reverse transcription-PCR. We demonstrated the usefulness of F+ RNA coliphages as an indicator of fecal contamination, but were unable to distinguish between human and non-human sources. F+ coliphage numbers in Table Rock Lake showed seasonal variation with the highest level of coliphage presence during the January sampling event.

The Continual Reassessment Method for Multiple Toxicity Grades: A Bayesian Quasi-Likelihood Approach

We consider the case of phase I trials for treatment of cancer or other severe diseases in which grade information is available about the severity of toxicity. Most dose allocation procedures dichotomize toxicity grades based on being dose limiting, which may not work well for severe and possibly irreversible toxicities such as renal, liver, and neurological toxicities, or toxicities with long duration. We propose a simple extension to the continual reassessment method (CRM), called the Quasi-CRM, to incorporate grade information. Toxicity grades are first converted to numeric scores that reflect their impacts on the dose allocation procedure, and then incorporated into the CRM using the quasi-Bernoulli likelihood. A simulation study demonstrates that the Quasi-CRM is superior to the standard CRM and comparable to a univariate version of the Bekele and Thall method (2004, Journal of the American Statistical Association 99, 26-35). We also present sensitivity analysis of the new method with respect to toxicity scores, and discuss practical issues such as extending the simple algorithmic up-and-down designs.

Amelogenin-mediated regulation of osteoclastogenesis, and periodontal cell proliferation and migration

We previously reported that amelogenin isoforms M180 and leucine-rich amelogenin peptide (LRAP) are expressed in the periodontal region, and that their absence is associated with increased cementum defects in amelogenin-knockout (KO) mice. The aim of the present study was to characterize the functions of these isoforms in osteoclastogenesis and in the proliferation and migration of cementoblast/periodontal ligament cells. The co-cultures of wild-type (WT) osteoclast progenitor and KO cementoblast/periodontal ligament cells displayed more tartrate-resistant acid phosphatase (TRAP)-positive cells than the co-cultures of WT cells. The addition of LRAP to both co-cultures significantly reduced RANKL expression and the TRAP-positive cells. Proliferation and migration rates of the KO cementoblast/periodontal ligament cells were lower than those of WT cells and increased with the addition of either LRAP or P172 (a porcine homolog of mouse M180). Thus, we demonstrate the regulation of osteoclastogenesis by LRAP, and the proliferation and migration of cementoblast/periodontal ligament cells by LRAP and P172.

Frequent requirement of hedgehog signaling in non-small cell lung carcinoma

Although it had previously been suggested that the hedgehog (HH) pathway might be activated in some lung tumors, the dependence of non-small cell lung carcinomas (NSCLC) for HH activity had not been comprehensively studied. During a screen of a panel of 60 human tumor cell lines with an HH antagonist, we observed that the proliferation of a subset of NSCLC cell lines was inhibited. These NSCLC cell lines express HH, as well as key HH target genes, consistent with them being activated through an autocrine mechanism. Interestingly, we also identified a number of NSCLC cell lines that express high levels of the downstream transcription factor GLI1 and harbor enhanced levels of HH activity, but appear insensitive to known HH antagonists. We hypothesized that the high levels of GLI1 in these cells would function downstream of the HH antagonist target, allowing them to bypass the antagonist-mediated block in proliferation. Consistent with this hypothesis, when the levels of GLI1 are knocked down in such cells, they become sensitive to these inhibitors. We go on to show that a large percentage of primary NSCLC samples express GLI1, consistent with constitutive activation of the HH pathway in these samples. Taken together, these results establish the involvement of the HH signaling pathway in a subset of NSCLCs.

Therapeutic potential of peptide deformylase inhibitors

Peptide deformylase (PDF) is an attractive target for antibacterial drug discovery. Progress in the biological characterisation of the enzyme, coupled with newly obtained mechanistic and structural insight, enabled the pharmaceutical industry to discover potent PDF inhibitors that can be considered as clinical development candidates for this new class of antibacterial agents. The in vitro and in vivo data for several lead PDF inhibitors suggest that the current PDF inhibitors are most suitable for the treatment of respiratory tract infections and they are not cross-resistant to the current clinically used antibiotics. Two PDF inhibitors, BB-83698 and VIC-104959, have progressed to Phase I clinical trials by intravenous and oral administration, respectively. Both of these compounds show promising in vitro and in vivo efficacy and an excellent safety profile. The pharmacokinetics in humans for both of the compounds suggest the possibility of a twice-daily dosing regimen for clinical use. Thus far, all of the data suggest a promising future for this new class of antibacterial agents.

The effect of simvastatin on triglyceride-rich lipoproteins in patients with type 2 diabetic dyslipidemia: a SILHOUETTE trial sub-study

OBJECTIVE

To determine if simvastatin effectively decreases the elevated levels of triglyceride (TG), TG-rich lipoproteins, and small, dense LDL particles, which are characteristic of diabetic dyslipidemia.

RESEARCH DESIGN AND METHODS

We conducted a prespecified analysis from a double-blind, placebo-controlled, randomized, 6-week crossover trial in patients with type 2 diabetes and low HDL-C (< 40 mg/dL). Each patient was randomized to 1 of 6 possible treatment arms; each patient received simvastatin 80 mg, simvastatin 40 mg, and placebo over 3 periods. We used the validated vertical auto profile (VAP) method to directly assess TG-rich lipoproteins and LDL subclasses. We assessed the efficacy of simvastatin to improve the lipoprotein profile in adult men (71%) and women (29%) (n = 151) with stable type 2 diabetes (HbA1C < 9%), LDL-C > 100 mg/dL, HDL-C < 40 mg/dL, and fasting TG level > 150 and < 700 mg/dL (median = 273 mg/dL).

MAIN OUTCOME MEASURES

Percentage change from baseline in IDL and VLDL (TG-rich lipoproteins), LDL subclasses, and additional lipoproteins at the end of each 6-week treatment interval; percentage of patients who reached NCEP ATP III non-HDL goal of < 130 mg/dL by the end of each 6-week period.

RESULTS

Both simvastatin 80 mg and 40 mg significantly reduced VLDL-C, VLDL3, and IDL, as well as the four LDL subclasses measured with VAP, compared with placebo. Simvastatin 80 mg, compared with simvastatin 40 mg, provided additional efficacy. With simvastatin 80 mg, 77.2% of patients not at their non-HDL-C goal of < 130 mg/dL at study baseline reached goal, compared with 65.7% following simvastatin 40 mg treatment, and 2.2% following placebo.

CONCLUSIONS

Treatment with simvastatin effectively reduced the elevated levels of TG-rich lipoproteins and improved LDL composition in patients with type 2 diabetes. A large percentage of these patients attained the NCEP ATP III non-HDL-C goal of < 130 mg/dL, which demonstrates the improvement of the atherogenic profile in these patients.

Modelling biological processes under anaerobic conditions through integrating titrimetric and off-gas measurements-applied to EBPR systems

An innovative method for modelling biological processes under anaerobic conditions is presented and discussed. The method is based on titrimetric and off-gas measurements. Titrimetric data is recorded as the addition rate of hydroxyl ions or protons that is required to maintain pH in a bioreactor at a constant level. An off-gas analysis arrangement measures, among other things, the transfer rate of carbon dioxide. The integration of these signals results in a continuous signal which is solely related to the biological reactions. When coupled with a mathematical model of the biological reactions, the signal allows a detailed characterisation of these reactions, which would otherwise be difficult to achieve. Two applications of the method to the enhanced biological phosphorus removal processes are presented and discussed to demonstrate the principle and effectiveness of the method.

Feasibility of controlling nitrification in predenitrification plants using DO, pH and ORP sensors

Experimental studies were carried out on a bench-scale nitrogen removal system with a predenitrification configuration to gain insights into the spatial and temporal variations of DO, pH and ORP in such systems. It is demonstrated that these signals correlate strongly with the operational states of the system, and could therefore be used as system performance indicators. The DO concentration in the first aerobic zone, when receiving constant aeration, and the net pH change between the last and first aerobic zones display strong correlations with the influent ammonia concentration for the domestic wastewater used in this study. The pH profile along the aerobic zones gives good indication on the extent of nitrification. The experimental results also showed a good correlation between ORP values in the last aerobic zone and effluent ammonia and nitrate concentrations, provided that DO in this zone is controlled at a constant level. These results suggest that the DO, pH and ORP sensors could potentially be used as alternatives to the on-line nutrient sensors for the control of continuous systems. An idea of using a fuzzy inference system to make an integrated use of these signals for on-line aeration control is presented and demonstrated on the bench-scale system with promising results. The use of these sensors has to date only been demonstrated in intermittent systems, such as sequencing batch reactor systems.

Effects of solids concentration, pH and carbon addition on the production rate and composition of volatile fatty acids in prefermenters using primary sewage sludge

Increasing evidence is emerging that the performance of enhanced biological phosphorus removal (EBPR) systems relies on not only the total amount but also the composition of volatile fatty acids (VFAs). Domestic wastewater often contains limited amounts of VFAs with acetic acid typically being the dominating species. Consequently, prefermenters are often employed to generate additional VFAs to meet the demand for carbon by EBPR and/or denitrification processes. Limited knowledge is currently available on the effects of operational conditions on the production rate and composition of VFAs in prefermenters. In this study, a series of controlled batch experiments were conducted with sludge from a full-scale prefermenter to determine the impact of solids concentration, pH and addition of molasses on prefermentation processes. It was found that an increase in solids concentration enhanced total VFA production with an increased propionic acid fraction. The optimal pH for prefermentation was in the range of 6-7 with significant productivity loss when pH was below 5.5. Molasses addition significantly increased the production of VFAs particularly the propionic acid. However, the fermentation rate was likely limited by the biological activity of the sludge rather than by the amount of molasses added.

Bacterial Peptide deformylase inhibitors: a new class of antibacterial agents

Peptide deformylase (PDF) is a prokaryotic metalloenzyme that is essential for bacterial growth but is not required by mammalian cells. Thus, it represents a selective and promising target for the development of new antibacterial agents. Since deformylase inhibitors have yet to be used clinically as antibacterial drugs, compounds targeting this enzyme should avoid cross-resistance with currently used antibacterial agents. The PDF enzyme is a ferrous ion-containing metallohydrolase, but a nickel-containing surrogate is routinely used in the laboratory for testing inhibitors due to its better stability. Enzymes from several bacterial species have been cloned and both their three-dimensional structures and co-crystal structures with bound inhibitor have been determined. As a metallo enzyme, PDF lends itself to the well-precedented mechanism-based rational drug design approach. Using structural and mechanistic information together with high throughput screening, several types of potent PDF inhibitors have been identified. PDF inhibitors identified to date share a common structural feature of a "chelator + peptidomimetic" scaffold. Although compounds with many different chelators inhibit the cell free enzyme, only compounds containing hydroxamic acid or N-formyl hydroxylamine exhibit appreciable antibacterial activity. Several lead inhibitors have demonstrated in vivo efficacy and an excellent safety profile. Two PDF inhibitors, VIC-104959 (LBM415) and BB-83698, have progressed to Phase I clinical trials. In this review, different PDF inhibitors are compared and their biological activities are discussed. Structure-activity relationships have been established and the implications of this work in the design of future PDF inhibitors are considered.