Nestin in immature embryonic neurons affects axon growth cone morphology and Semaphorin3a sensitivity.

Correct wiring in the neocortex requires that responses to an individual guidance cue vary among neurons in the same location, and within the same neuron over time. Nestin is an atypical intermediate filament expressed strongly in neural progenitors and is thus used widely as a progenitor marker. Here we show a subpopulation of embryonic cortical neurons that transiently express nestin in their axons. Nestin expression is thus not restricted to neural progenitors, but persists for 2-3 d at lower levels in newborn neurons. We found that nestin-expressing neurons have smaller growth cones, suggesting that nestin affects cytoskeletal dynamics. Nestin, unlike other intermediate filament subtypes, regulates cdk5 kinase by binding the cdk5 activator p35. Cdk5 activity is induced by the repulsive guidance cue Semaphorin3a (Sema3a), leading to axonal growth cone collapse in vitro. Therefore, we tested whether nestin-expressing neurons showed altered responses to Sema3a. We find that nestin-expressing newborn neurons are more sensitive to Sema3a in a roscovitine-sensitive manner, whereas nestin knockdown results in lowered sensitivity to Sema3a. We propose that nestin functions in immature neurons to modulate cdk5 downstream of the Sema3a response. Thus, the transient expression of nestin could allow temporal and/or spatial modulation of a neuron's response to Sema3a, particularly during early axon guidance.

Uncoupling the solids retention times of flocs and granules in mainstream deammonification: A screen as effective out-selection tool for nitrite oxidizing bacteria.

This study focused on a physical separator in the form of a screen to out-select nitrite oxidizing bacteria (NOB) for mainstream sewage treatment. This separation relied on the principle that the NOB prefer to grow in flocs, while anammox bacteria (AnAOB) reside in granules. Two types of screens (vacuum and vibrating) were tested for separating these fractions. The vibrating screen was preferred due to more moderate normal forces and additional tangential forces, better balancing retention efficiency of AnAOB granules (41% of the AnAOB activity) and washout of NOB (92% activity washout). This operation resulted in increased NOB out-selection (AerAOB/NOB ratio of 2.3) and a total nitrogen removal efficiency of 70% at influent COD/N ratio of 1.4. An effluent total nitrogen concentration <10mgN/L was achieved using this novel approach combining biological selection with physical separation, opening up the path towards energy positive sewage treatment.

Impact of carbon to nitrogen ratio and aeration regime on mainstream deammonification.

While deammonification of high-strength wastewater in the sludge line of sewage treatment plants has become well established, the potential cost savings spur the development of this technology for mainstream applications. This study aimed at identifying the effect of aeration and organic carbon on the deammonification process. Two 10 L sequencing bath reactors with different aeration frequencies were operated at 25°C. Real wastewater effluents from chemically enhanced primary treatment and high-rate activated sludge process were fed into the reactors with biodegradable chemical oxygen demand/nitrogen (bCOD/N) of 2.0 and 0.6, respectively. It was found that shorter aerobic solids retention time (SRT) and higher aeration frequency gave more advantages for aerobic ammonium-oxidizing bacteria (AerAOB) than nitrite oxidizing bacteria (NOB) in the system. From the kinetics study, it is shown that the affinity for oxygen is higher for NOB than for AerAOB, and higher dissolved oxygen set-point could decrease the affinity of both AerAOB and NOB communities. After 514 days of operation, it was concluded that lower organic carbon levels enhanced the activity of anoxic ammonium-oxidizing bacteria (AnAOB) over denitrifiers. As a result, the contribution of AnAOB to nitrogen removal increased from 40 to 70%. Overall, a reasonably good total removal efficiency of 66% was reached under a low bCOD/N ratio of 2.0 after adaptation.

Expanding DEMON Sidestream Deammonification Technology Towards Mainstream Application.

A cross-Atlantic R&D-cooperation involving three large utilities investigated the feasibility of mainstream deammonification-the application of partial nitritation/anammox for full-plant treatment of municipal wastewater at ambient temperatures. Two major process components have been implemented, 1) bioaugmentation of aerobic- and anaerobic ammonia oxidizers (AOB and AMX) from the DEMON-sidestream sludge liquor treatment to the mainstream and 2) implementation of hydrocyclones to select for anammox granules and retain them in the system. Different operation modes have been tested at laboratory- and pilot-scale in order to promote the short-cut (more direct anammox route) in nitrogen removal metabolism. At the full-scale installation at Strass WWTP, stable repression of nitrite oxidizing biomass (NOB) has been achieved for several months. Significant anammox enrichment in the mainstream has been monitored while high efficiency in the sidestream-process has been maintained (96% annual average ammonia removal).

Going for mainstream deammonification from bench to full scale for maximized resource efficiency.

A three-pronged coordinated research effort was undertaken by cooperating utilities at three different experimental scales investigating bioaugmentation, enrichment and performance of anammox organisms in mainstream treatment. Two major technological components were applied: density-based sludge wasting by a selective cyclone to retain anammox granules and intermittent aeration to repress nitrite oxidizers. This paper evaluates process conditions and operation modes to direct more nitrogen to the resource-saving metabolic route of deammonification.

Discrepancies in glomerular and tubulointerstitial/vascular immune complex IgG subclasses in lupus nephritis.

BACKGROUND AND OBJECTIVES: Lupus nephritis is characterized by glomerular and extraglomerular immune complex deposition in the kidney. It is unclear whether the same circulating immune complexes deposit in the glomeruli and in extraglomerular structures, or whether they are pathogenetically different. Differences in the IgG subclass composition may point towards different pathways in the formation of glomerular and extraglomerular immune complexes. Therefore we investigated IgG subclass distribution in the immune complex deposits at these anatomic sites. DESIGN: A total of 84 biopsies diagnosed as lupus nephritis and classified according to the International Society of Nephrology/Renal Pathology Society (ISN/RPS) 2003 classification, were examined by direct immunofluorescence staining for IgG subclasses. The IgG subclass composition in the glomerular, tubular basement membrane (TBM) and vascular wall deposits was compared. We also correlated the presence/absence of interstitial inflammation and IgG subclasses in the TBM and vascular deposits. Lastly, we looked for correlation between staining for IgG subclasses and complement C1q and C3 staining. RESULTS: IgG staining was present in the TBM in 52/84 biopsies, and in the vascular walls in 40/84 biopsies. IgG subclass distribution was discrepant between glomerular and TBM deposits in 36/52 biopsies, and between glomerular and vascular deposits in 27/40 biopsies. Interstitial inflammation did not correlate with the presence of IgG staining or distribution of IgG subclasses in the TBM. Interstitial inflammation was more common in biopsies of African-American patients than Caucasian patients. The IgG subclass staining correlated with C1q staining in all the three compartments. CONCLUSIONS: The antibody composition of the glomerular and extraglomerular immune complex deposits appear to differ from each other. They may not represent the same preformed immune complexes from the circulation. It is likely that their pathogenesis and site of formation are different.

Systematic evaluation of biofilm models for engineering practice: components and critical assumptions.

Biofilm models are valuable tools for the design and evaluation of biofilm-based processes despite several uncertainties including the dynamics and rate of biofilm detachment, concentration gradients external to the biofilm surface, and undefined biofilm reactor model calibration protocol. The present investigation serves to (1) systematically evaluate critical biofilm model assumptions and components and (2) conduct a sensitivity analysis with the aim of identifying parameter subsets for biofilm reactor model calibration. AQUASIM was used to describe submerged-completely mixed combined carbon oxidation and nitrification IFAS and MBBR systems, and tertiary nitrification and denitrification MBBRs. The influence of uncertainties in model parameters on relevant model outputs was determined for simulated scenarios by means of a local sensitivity analysis. To obtain reasonable simulation results for partially penetrated biofilms that accumulated a substantial thickness in the modelled biofilm reactor (e.g. 1,000 microm), an appropriate biofilm discretization was applied to properly model soluble substrate concentration gradients and, consistent with the assumed mechanism for describing biofilm biomass distribution, biofilm biomass spatial variability. The MTBL thickness had a significant impact on model results for each of the modelled reactor configurations. Further research is needed to develop a mathematical description (empirical or otherwise) of the MTBL thickness that is relevant to modern biofilm reactors. No simple recommendations for a generally applicable calibration protocol are provided, but sensitivity analysis has been proven to be a powerful tool for the identification of highly sensitive parameter subsets for biofilm (reactor) model calibration.

Balancing yield, kinetics and cost for three external carbon sources used for suspended growth post-denitrification.

Facilities across North America are designing plants to meet stringent limit of technology (LOT) treatment for nitrogen removal. In the Mid-Atlantic region of the United States, this is in response to the Chesapeake Bay Agreement, which limit effluent total nitrogen discharges from wastewater treatment plants to between 3-5 mg/L. Since denitrification is crucial for the removal of nitrogen, maximizing this process step will result in a decrease in nutrient load to the receiving waters. Of particular interest is the use of an alternate external carbon source to replace the most commonly used carbon, methanol. Three external carbon sources were evaluated in this study including: methanol, ethanol and acetate at 13 degrees C. The aim of this study was to evaluate the relative benefits and constraints for using these three carbon types. Laboratory scale Sequencing Batch Reactors (SBRs) were set up to grow and acclimate carbon free biomass to the specified substrate while in-situ Specific Denitrification Rates (SDNRs) were conducted concurrently. The results suggest that the SDNRs for acetate (31.0 + or - 4.6 mgNO(3)-N/gVSS/hr) and ethanol (29.6 + or - 5.6 mgNO(3)-N/gVSS/hr) are higher than that for methanol (10.1 + or - 2.5 mgNO(3)-N/gVSS/hr). The yield coefficients in g COD/g COD were observed to follow a similar trend with values of 0.45 + or - 0.05 for methanol, 0.53 + or - 0.06 for ethanol and 0.66 + or - 0.06 for acetate.

Evaluation of alternative electron donors for denitrifying moving bed biofilm reactors (MBBRs).

The effectiveness of four different electron donors, specifically methanol, ethanol, glycerol, and sulfide (added as Na(2)S), were evaluated in post-denitrifying bench-scale moving bed biofilm reactors (MBBRs). With the requirement for more wastewater treatment plants to reach effluent total nitrogen levels approaching 3 mg/L, alternative electron donors could promote more rapid MBBR startup/acclimation times and increased cold weather denitrification rates compared to methanol, which has been most commonly used for post-denitrification processes due to low cost and effectiveness. While the application of alternative substrates in suspended growth processes has been studied extensively, fixed film post denitrification processes have been designed to use primarily low yield substrates like methanol. Bench-scale MBBRs were operated continuously at 12 degrees Celsius, and performance was monitored by weekly sampling and insitu batch profile testing. Ethanol and glycerol, though visually exhibited much higher biofilm carrier biomass content, performed better than methanol in terms of removal rate (0.9 and 1.0 versus 0.6 g N/m(2)/day, respectively.) Maximum denitrification rate measurements from profile testing suggested that ethanol and glycerol (2.2 and 1.9 g N/m(2)/day, respectively) exhibited rates that were four times that of methanol (0.49 g N/m(2)/day.) Sulfide also performed much better than either of the other three electron donors with maximum rates at 3.6 g N/m(2)/day and with yield (COD/NO(3)-N) that was similar to or slightly less than that of methanol.

Denitrification with carbon addition--kinetic considerations.

The Blue Plains Advanced Wastewater Treatment Plant (Washington, D.C.) uses methanol as an external carbon source in a postdenitrification process, to achieve low effluent total nitrogen concentrations. This becomes more difficult in winter, at lower mixed liquor temperatures and higher flows, as a consequence of the kinetic behavior of the methanol-utilizing heterotrophs. The paper reports on an experimental batch test study conducted on Blue Plains postdenitrification sludge to investigate (1) the maximum specific growth rate of methanol-utilizing heterotrophs (Mu(METH)); (2) the temperature dependency of the growth rate; and (3) the efficacy of alternate substrates (ethanol, acetate, and sugar). A limited number of tests were conducted on sludge from two other treatment plants with methanol addition.

Enteric-coated cholylsarcosine microgranules for the treatment of short bowel syndrome.

Cholylsarcosine (CS) is a semisynthetic bile salt that may be useful in bile salt replacement therapy of short bowel syndrome (SBS). In SBS the bile salt pool becomes depleted, disturbing the uptake of dietary lipids and resulting in weight loss. Previous studies showed that CS in a simple capsule formulation of 1.5-12 g day(-1) can increase the uptake of lipids but often results in gastric irritation. In this work a microgranule dosage form was developed to protect the gastric mucosa while facilitating rapid generation of CS levels in the duodenum. CS microgranules were produced by wet granulation and coated with Eudragit L30D-55 in a fluidized-bed coater. The in-vitro dissolution rate of CS from the microgranules was investigated with USP apparatus under fasted- and fed-state conditions. CS release was delayed under simulated gastric conditions (pH 1.2 and 4.5) but was very fast at higher pH values (5.5, 5.8 and 6.5) more typical of the duodenum. In a pilot clinical trial, four patients received 4 g CS with meals (1.5 g with lunch, 2.5 g with dinner) for 1 week. The parameters investigated were fat absorption coefficient (FAC%), serum beta-carotene level and faecal weight. Although study numbers were too small to achieve statistical significance, the serum beta-carotene level and FAC% increased in the three patients who completed the trial. As expected, the fecal weight did not change. The results indicate that the CS microgranules are promising for the treatment of the intraluminal bile salt deficiency in patients with SBS.

In vivo evaluation of a novel pH- and time-based multiunit colonic drug delivery system.

BACKGROUND: Targeted drug delivery to the colon is important for topical treatment of inflammatory bowel diseases. Established targeting systems predominantly focus on either pH- or time-dependent release, or bacterial degradation. AIM: To perform a three-phase, crossover design trial evaluating a novel combined pH- and time-based multiunit delivery system. METHODS: Twelve healthy male volunteers each received 200 mg of caffeine as either uncoated immediate release tablets, coated pellets with pH-dependent rapid release (EUDRAGIT FS 30D), and pellets with pH- and time-based release (inner layer EUDRAGIT RL/RS 30D; outer layer EUDRAGIT FS 30D). Orocecal transit time was measured using lactose-[13C]ureide. Serum concentrations of caffeine were measured by high-performance liquid chromatography. RESULTS: In contrast to the uncoated tablet, both coated systems reached the ileocecal region almost at the same time (3.19 +/- 0.71 and 3.33 +/- 0.81 h). Serum caffeine profiles were significantly prolonged for the pH and time delivery system compared with the pH-only based system (median tmax 12.0 vs. 5.5 h; P < 0.001). This was further reflected by a lower Cmax value and a lower area under the curve within 24 h after application. CONCLUSION: Compared with the conventional delivery systems, drug release from the new dosage form may offer a new dimension for the oral treatment of mid to distal ulcerative colitis.

[Colorectal cancer and folate]. / Kolorektales Karzinom und Folsäure.

Nutritional factors are important contributors to colorectal cancer prevention. There is some evidence to suggest that a high dietary folate intake is associated with a reduced risk of colorectal cancer. Folate, which is found in green leafy vegetables, is involved in C1 group transfer and contributes to purin and thymi-dilate synthesis as well as to DNA methylation. Alterations in gene expression and DNA damage are discussed to result from low folate levels and might be associated with an elevated risk of colorectal malignancies. This hypothesis can be supported by the finding that a common polymorphism in the methylentetrahydrofolate reductase gene enhances the risk of colorectal cancer when folate status is low. Both retrospective and prospective epidemiologic studies confirm the observation that a high intake of folate correlates with a lower risk of colorectal cancer. There is also evidence from epidemiological studies that diets which are low in methyl donors, such as low contents of folate and/or methionine combined with relatively high alcohol consumption, even enhance the risk of colorectal cancer. A small number of intervention trials provide first evidence that folate intakes far above recommended dietary allowances might influence possible biomarkers of colorectal tumours.

Evaluating the role of microbial stress response mechanisms in causing biological treatment system upset.

It is known that microbial stress mechanisms play a significant role in short-term microbial adaptation to environmental perturbations, and activation of these mechanisms enhance a cell's chance for surviving the perturbation with minimal damage. Although the target of these mechanisms is protective at the cellular level, the effect may be disruptive at the macroscopic level in engineered bioreactor systems. In this paper, it is proposed that these mechanisms are activated in response to wastewater influent perturbations and may be a significant cause of activated sludge treatment process upset. Selected microbial stress responses are reviewed and hypotheses indicating their potential role in treatment process upset are proposed. A research approach that was previously used to identify the mechanistic cause of deflocculation during perturbation by electrophilic chemicals is summarized, and a protocol for future experiments geared toward establishing source-cause-effect relationships for a range of wastewater upset conditions is put forth. Identifying source-cause-effect relationships will provide a basis for development of new monitoring technologies and operational strategies for systems under the influence of influent chemical perturbations.

Stress protein expression in domestic activated sludge in response to xenobiotic shock loading.

Using the Western blot immunochemical analysis method, the heat shock protein, GroEL, was found to be either induced or repressed in activated sludge microorganisms exposed to a range of xenobiotics. At the EC25 concentration, pentachlorophenol (PCP), cadmium, nickel, 2,4-dichloroaniline, benzoquinone, 2,4-dinitrophenol, and 1,1,1-trichloroethane all rapidly induced measurable GroEL expression, even though the time-dependent response for each of these compounds was somewhat varied. Toluene and hydroquinone resulted in repression of GroEL expression to levels below that measured in the control mixed liquor. For PCP concentrations at or exceeding the EC25, there was a significant and consistent increase in effluent volatile suspended solids from activated sludge sequencing batch reactors relative to unstressed controls. These preliminary results indicate that stress proteins may serve as sensitive and rapid indicators of toxicity which can adversely impact treatment process performance in activated sludge systems.

The immunochemical detection of stress proteins in activated sludge exposed to toxic chemicals.

The heat shock protein, GroEL, was found to be induced in activated sludge cultures exposed to perturbations of chemicals (cadmium, pentachlorophenol, and acetone) or heat stress. In laboratory activated sludge reactors, GroEL was rapidly induced (within minutes) in the presence of 5 mg/l or greater total cadmium. At 5 mg/l cadmium, however, moderate to insignificant changes in activated sludge process performance indicators [effluent suspended solids concentration, chemical oxygen demand (COD) removal, and specific oxygen uptake rate] were observed. As total cadmium concentrations increased above 5 mg/l, there was a significant and consistent increase in effluent volatile suspended solids concentrations from activated sludge sequencing batch reactors relative to unstressed controls. These results indicate that stress proteins may serve as sensitive and rapid indicators of mixed liquor toxicity which can adversely impact treatment process performance, but that GroEL may not be a good candidate protein for this purpose.

Detection of GroEL in activated sludge: a model for detection of system stress.

GroEL is a ubiquitous constitutively synthesized protein that is also stress inducible. Activated sludge, which is a standard biological process used in wastewater treatment systems, is made up of a diverse microbial consortium. The synthesis of GroEL in activated sludge was significantly induced after heat (42 degrees C) shock. The increased level of GroEL expression was shown to be due to de novo protein synthesis. We have demonstrated a method which shows that stress proteins can be detected in activated sludge, and propose their use as specific indicators of system stress.

The influence of the MAPK pathway on T cell lineage commitment.

During development, progenitor thymocytes differentiate into either CD4 or CD8 T cells, and this fate decision depends on the specificity of the T cell antigen receptor (TCR) for MHC class II or class I molecules. Based on the mechanisms of fate specification known for simple metazoan organisms, we sought to determine whether the extracellular signal-related kinases (ERKs) play a role in T cell differentiation and lineage commitment. Using a dominant gain-of-function mutant of the erk2 gene, we show that differentiation into the CD4 lineage is favored. We also show that, conversely, the addition of a pharmacological inhibitor of the ERK pathway favors differentiation into the CD8 lineage. We present a quantitative selection model that incorporates these results as well as those of recent reports on the role of Notch in T cell lineage specification.

Behaviour problems associated with lack of speech in people with learning disabilities.

It has been observed in a population of people with learning disabilities that people with good understanding but no speech have significantly more behaviour problems than those with good speech. This observation was confirmed by testing a data set of 3662 people. The purpose of the study was to stress the importance of teaching communication techniques as early as possible in order to pre-empt behaviour problems.

Role of the CD6 glycoprotein in antigen-specific and autoreactive responses of cloned human T lymphocytes.

CD6 is a 130 000 MW T-cell surface glycoprotein that can deliver coactivating signals to mature T lymphocytes. Studies using monoclonal antibodies (mAb) have defined at least four epitopes on CD6, and distinct functional responses are elicited by mAb to the different epitopes. The function of CD6 is unknown. Multiple CD6 ligands are predicted, based on data that a soluble CD6 fusion protein precipitates at least three peptides. A cDNA clone for one of these ligands, termed activated leucocyte-cell adhesion molecule (ALCAM) has recently been isolated. In order to further characterize the role of CD6 in cell-cell interactions, we have examined the role of CD6 in a variety of responses by tetanus toxoid (TT) specific human T-cell clones. Anti-CD6 mAb UMCD6 (epitope 3) inhibits antigen-specific responses of such clones to TT, but not to the superantigen SEA. Responses of clones to nominal antigen are CD6-dependent using either peripheral blood mononuclear cells (PBMC) or macrophage-depleted E rosette negative cells as the antigen-presenting cell (APC) population. Furthermore, these clones made autoreactive with DNA methyltransferase inhibitors express increased CD6, and autoreactivity is inhibited by UMCD6. Taken together, the data suggests the existence of a functional CD6 ligand in peripheral blood which is expressed by APC, including cells other than macrophages. Interactions between CD6 and CD6 ligands may regulate both antigen specific and autoreactive responses of human T lymphocytes.