Endpoint Determination Research Articles

Abstract 2872: Image analysis algorithms for whole-slide counting, regional assignment, and subtype classification of tumor-associated macrophages (TAMs).

Abstract Tumor-associated macrophages (TAMs) regulate cancer progression on multiple levels, including angiogenesis, treatment response, and metastasis. Additionally, multiple studies have demonstrated a significant association between clinical outcome and TAM abundance, M1 vs. M2 subtype, and intratumoral distribution into stromal or epithelial compartments. However, manual counting of TAMs and assignment into tumor stroma or epithelial nests is laborious, inaccurate, subjective, and does not provide a statistically optimal sample size. These pitfalls may be limiting its utility as a diagnostic tool or an endpoint in drug efficacy studies. Using tissue sections from human breast cancers as a model, we have developed image analysis algorithms for the rapid automated counting and compartmental assignment of total TAMs (CD68+) and TAMs of the more strongly tumor-promoting M2 subtype (CD163+). Using whole slide scanning and proprietary image analysis tools called Feature Analysis on Consectutive Tissue Sections (FACTS), we have developed an approach to not only tally but also map the location of CD68+ and CD163+ macrophages in serial tissue sections, align those sections, and provide information about regional distribution of these macrophages. These outcomes can also be aligned with other serial sections containing relevant biomarkers associated with macrophage infiltration such as hypoxia or angiongenesis, using our proprietary multivariate correlation analysis tool Multivariatemap. Additionally, we have begun investigations into the association of these regional macrophage densities with clinical outcome using patient data available for the model set. These approaches represent a powerful toolkit for elucidating significant quantitative associations between TAMs and tumor vasculature, hypoxia, or other relevant features or markers, for the determination of prognostic or drug efficacy endpoints. Citation Format: Brian E. Laffin, Joseph Krueger, Mohamed Salama. Image analysis algorithms for whole-slide counting, regional assignment, and subtype classification of tumor-associated macrophages (TAMs). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 2872. doi:10.1158/1538-7445.AM2013-2872

Endocrine effects of chemicals: Aspects of hazard identification and human health risk assessment

Hazard and risk assessment of chemicals with endocrine activity is hotly debated due to claimed non-monotonous dose–response curves in the low-dose region. In hazard identification a clear definition of “endocrine disruptors” (EDs) is required; this should be based on the WHO/IPCS definition of EDs and on adverse effects demonstrated in intact animals or humans. Therefore, endocrine effects are a mode of action potentially resulting in adverse effects; any classification should not be based on a mode of action, but on adverse effects. In addition, when relying on adverse effects, most effects reported in the low-dose region will not qualify for hazard identification since most have little relation to an adverse effect. Non-monotonous dose–response curves that had been postulated from limited, exploratory studies could also not be reproduced in targeted studies with elaborate quality assurance. Therefore, regulatory agencies or advisory bodies continue to apply the safety-factor method or the concept of “margin-of-exposure” based on no observed adverse effect levels (NOAELs) in the risk assessment of chemicals with weak hormonal activity. Consistent with this approach, tolerable levels regarding human exposure have been defined for such chemicals. To conclusively support non-monotonous dose–response curves, targeted experiments with a sufficient number of animals, determination of adverse endpoints, adequate statistics and quality control would be required.

Mixture Component Prediction Using Iterative Optimization Technology (Calibration-Free/Minimum Approach)

Process analytical technology (PAT) plays an important role in the pharmaceutical industry. PAT is used extensively in process development, process understanding, and process control. Often, quantitative measurements are desired/required and a calibrated model will have to be developed and implemented. The development, implementation, and maintenance of these quantitative models are both resource and time intensive. This paper describes a calibration-free/minimum approach, iterative optimization technology (IOT), which is used to predict (without calibration standards) the composition of a mixture while maintaining a similar predictability to calibration standard models. It typically involves using only pure standard spectra (collected prior to the analysis) and sample spectra collected during the analysis. This technology is applicable for predicting compositions during development of pharmaceutical products (where the synthetic route, formulation, or process is not set) and is not intended for use in good manufacturing practice (GMP) manufacture where quantitative measurements are made using validated models. For ideal mixture cases, the mixture composition is iteratively computed at every sample time point to minimize an excess absorption subject to constraints (e.g., mixture constraints, upper/lower limits). Linear IOT is used to describe these ideal mixture cases. For nonideal mixture cases, the excess absorption, including the nonlinear characteristic, is first represented by a Box-Cox transformation. A limited number of training/calibration samples is required for these nonlinear examples. The mixture composition is then iteratively obtained in a similar optimization framework as linear IOT. Nonlinear IOT is used to describe these nonideal mixture cases. Linear and nonlinear IOT have provided comparable prediction accuracy on binary and ternary mixtures as compared to a calibrated partial least squares (PLS) model. IOT enhanced the understanding of dosage form blending processes by determining the composition/ratio of all (spectrally discriminated) components in the blend in real time. As composition is predicted each revolution, determination of the blending end point (does each component trend meet the known target mixture ratio) can be easily determined. Linear and nonlinear IOT can also be used to aid process understanding via detecting/representing molecular interaction effects utilizing the excess absorption calculation. The effectiveness of the linear and nonlinear IOT is demonstrated through four online and offline pharmaceutical process examples (bin-blending process, rotary tablet press feed frame process, and two different solvent mixtures).

A novel gadolinium ion-selective membrane electrode based on 2-(4-phenyl-1, 3-thiazol-2-yliminomethyl) phenol

A new gadolinium(III) selective electrode has been developed from poly vinyl chloride (PVC) matrix membrane which is based on synthesized neutral carrier [L1] 2-(2-aminothiazol-4-yl)phenol and [L2] 2-(4-phenyl-1,3-thiazol-2-yliminomethyl)phenol as ionophores. The membrane having a composition of ionophore (L2):PVC:plasticizer (acetophenone):additive (sodium tetraphenylborate) in the ratio of 5:33:60:2 exhibited calibration performance over a wide range of concentration of gadolinium (9.38×10−7 to 1.0×10−2 M) and exhibited a Nernst slope of 19.5±0.5mV per decade of Gd(III) activity. It exhibited a quick response time of 8s and its potential response was independent of pH across the pH range of 3.5–8.5. The membrane can be used with a good reproducibility over a period of 3 months. Membrane sensor was used as a indicator electrode for determination of end point in potentiometric titration of Gd (III) ion with EDTA. The proposed membrane electrodes were successfully applied for the determination of the concentration of gadolinium (III) ion in a mineral sample.

Development and in-line validation of a Process Analytical Technology to facilitate the scale up of coating processes

Incorporation of an active pharmaceutical ingredient (API) into the coating layer of film-coated tablets is a method mainly used to formulate fixed-dose combinations. Uniform and precise spray-coating of an API represents a substantial challenge, which could be overcome by applying Raman spectroscopy as process analytical tool. In pharmaceutical industry, Raman spectroscopy is still mainly used as a bench top laboratory analytical method and usually not implemented in the production process. Concerning the application in the production process, a lot of scientific approaches stop at the level of feasibility studies and do not manage the step to production scale and process applications. The present work puts the scale up of an active coating process into focus, which is a step of highest importance during the pharmaceutical development. Active coating experiments were performed at lab and production scale. Using partial least squares (PLS), a multivariate model was constructed by correlating in-line measured Raman spectral data with the coated amount of API. By transferring this model, being implemented for a lab scale process, to a production scale process, the robustness of this analytical method and thus its applicability as a Process Analytical Technology (PAT) tool for the correct endpoint determination in pharmaceutical manufacturing could be shown. Finally, this method was validated according to the European Medicine Agency (EMA) guideline with respect to the special requirements of the applied in-line model development strategy.

Recommendations and Practices to Optimize Stroke Therapy

On June 20 and 21, 2012, a National Institute of Neurological Disorders and Stroke-sponsored workshop on “Optimizing the Predictive Value of Preclinical Research” was held in Washington, DC.1 The primary objective of the workshop was to review deficiencies in preclinical and translational research and provide recommendations or guidelines to improve the rigor of preclinical research. The following is based on open discussions held at the meeting and panel recommendations for the application of basic principles of experimental design and reporting transparency that are currently standard of practice for stroke clinical trials. This article, which includes author interpretations of discussions, emphasizes the need for good laboratory practices, transparent scientific reporting, and the use of translational research models with clinically relevant end points to develop new strategies to treat stroke. There is a critical medical need for new therapeutic strategies to treat acute ischemic stroke and hemorrhagic stroke to reduce mortality and improve the quality of life for stroke victims. Current US statistics indicate that stroke is the fourth leading cause of death and the leading cause of adult disability in the United States, with upward of 795 000 victims annually who suffer a new or recurrent stroke, despite improved diet, and control of diabetes mellitus, hypertension, and hypercholesterolemia. Currently, the only Food and Drug Administration-approved treatment for stroke is the thrombolytic, tissue plasminogen activator (tPA) if administered within 3 hours of a stroke. Recently, the therapeutic window for tPA has been increased and shown to be beneficial if patients are treated within 4.5 hours of an ischemic stroke.2–4 However, the Food and Drug Administration (FDA) has not yet approved the extension of the time window >3 hours. Although thrombolysis is now widely accepted as a standard of care for acute ischemic stroke, only a minority (6%) of …

In-Line Multipoint Near-Infrared Spectroscopy for Moisture Content Quantification during Freeze-Drying

During the past decade, near-infrared (NIR) spectroscopy has been applied for in-line moisture content quantification during a freeze-drying process. However, NIR has been used as a single-vial technique and thus is not representative of the entire batch. This has been considered as one of the main barriers for NIR spectroscopy becoming widely used in process analytical technology (PAT) for freeze-drying. Clearly it would be essential to monitor samples that reliably represent the whole batch. The present study evaluated multipoint NIR spectroscopy for in-line moisture content quantification during a freeze-drying process. Aqueous sucrose solutions were used as model formulations. NIR data was calibrated to predict the moisture content using partial least-squares (PLS) regression with Karl Fischer titration being used as a reference method. PLS calibrations resulted in root-mean-square error of prediction (RMSEP) values lower than 0.13%. Three noncontact, diffuse reflectance NIR probe heads were positioned on the freeze-dryer shelf to measure the moisture content in a noninvasive manner, through the side of the glass vials. The results showed that the detection of unequal sublimation rates within a freeze-dryer shelf was possible with the multipoint NIR system in use. Furthermore, in-line moisture content quantification was reliable especially toward the end of the process. These findings indicate that the use of multipoint NIR spectroscopy can achieve representative quantification of moisture content and hence a drying end point determination to a desired residual moisture level.

Effects of silver nanoparticles on microbial growth dynamics

Engineered metal nanoparticles are increasingly used in consumer products, in part as additives that exhibit advantageous antimicrobial properties. Conventional nanoparticle susceptibility testing is based largely on determination of nontemporal growth profiles such as measurements of inhibition zones in common agar diffusion tests, counting of colony-forming units, or endpoint or regular-interval growth determination via optical density measurements. For better evaluation of the dynamic effects from exposure to nanoparticles, a cultivation-based assay was established in a 96-well format and adapted for time-resolved testing of the effects of nanoparticles on micro-organisms. The modified assay allowed simultaneous cultivation and on-line analysis of microbial growth inhibition. The automated high-throughput assay combined continuous monitoring of microbial growth with the analysis of many replicates and was applied to Cupriavidus necator H16 test organisms to study the antimicrobial effects of spherical silver [Ag(0)] nanoparticles (primary particle size distribution D90 < 15 nm). Ag(0) concentrations above 80 μg ml(-1) resulted in complete and irreversible inhibition of microbial growth, whereas extended lag phases and partial growth inhibition were observed at Ag(0) concentrations between 20 and 80 μg ml(-1) . Addition of Ag(0) nanoparticles at different growth stages led to either complete inhibition (addition of 40 μg ml(-1) Ag(0) from 0 h to 6 h) or resulted in full recovery (40 μg ml(-1) Ag(0) addition ≥9 h). Contrary to the expected results, our data indicate growth stimulation of C. necator at certain Ag(0) nanoparticle concentrations, as well as varying susceptibility to nanoparticles at different growth stages. These results underscore the need for time-resolved analyses of microbial growth inhibition by Ag(0) nanoparticles. Due to the versatility of the technique, the assay will likely complement existing microbiological methods for cultivation and diagnostics of microbes, in addition to tests of other antimicrobial nanoparticles.

Optimization of Curvilinear Mandible Distraction Using 3-Dimensional Computer-Simulated Modeling

Multi-vector distraction osteogenesis has been described for use in the reconstruction of complex mandible deformities. Using 3-dimensional computer simulation, the location of the osteotomy and arc of the device can be predetermined, allowing for precise planning and determination of end points. Here, we discuss our experience using this technique and propose methods to optimize outcomes and minimize discrepancies in the projected results. Three patients who underwent curvilinear mandible distraction and preoperative computer-simulated planning are described. After simulation to determine level of osteotomy and arc of the curvilinear distractor device, design-specific guides were constructed. Intraoperatively, custom guides were used to precisely perform the osteotomy and for placement of each distractor. After the completion of distraction and device removal, the correlation of distraction end points, occlusion, and the volumes of the mandibles were analyzed. A vertical difference of 2.6 mm (shorter) from the proposed final position and an 8-mm sagittal difference (under correction) were seen in the first patient. In the second patient, the final position had a vertical difference of 5.7 mm (shorter) and a sagittal difference of 14 mm (undercorrected). In the third patient, after first simulating anterior rotation of the condyle before osteotomy and vector design, the final and simulated end points differed approximately 0.6 mm vertically (shorter) and 4.3 mm sagittally (undercorrected) Preoperative 3D simulation and planning is a useful adjunct in curvilinear mandible distraction; however, the forces of the muscles of mastication and the restrictive soft tissue envelope must be accounted for in the design to achieve precise end results.

BiotecVisions 2012, November

BiotecVisions 2012, November

Improved protocols for histamine sensitization testing of acellular pertussis vaccines

The histamine sensitization test is a widely used method for measuring the residual toxicity of pertussis toxin in acellular pertussis vaccines. Although it has been used as a routine assay for decades, the current protocols are difficult to standardize because the test results vary considerably and are based on several factors, including mouse strain, age and sex. In this study, we observed that mice of strains CD1, ddY and C57/BL6 were sufficiently sensitive to pertussis toxin among six mice strains tested and that aged male mice were more sensitive to pertussis toxin than younger or female mice. Using this animal model, we showed pertussis toxin dose-dependent responses in the two histamine sensitization test protocols based on either lethal end-point determination or mouse rectal temperature measurement. Sensitivity to pertussis toxin was further enhanced by the addition of lipopolysaccharide in both methods. With these improvements, pertussis toxin activity can be estimated more accurately and reproducibly using a reduced number of animals.

Influence of lactic acid bacteria on the oxidation–reduction potential of buckwheat (Fagopyrum esculentum Moench) sourdoughs

The influence of lactic acid bacteria (LAB) growth on oxidation–reduction potential (ORP) of buckwheat sourdoughs was investigated. Sourdough fermentations are widely used for the production of bread and other bakery products. Until now the pH value is the most used control parameter taken into account during sourdough technology and no information is available about the influence of sourdough microbiota on the ORP or the use of redox potential (Eh7) measurements as a fermentation control parameter. The influence of growth and metabolism of lactobacilli on the oxidation–reduction potential of buckwheat (Fagopyrum esculentum Moench) sourdoughs was investigated. Upon inoculation with LAB, ORP changes were observed. Each strain exhibits a different ORP time course curve. The Eh7 after 8 h using Lactobacillus plantarum, Lactobacillus sakei, Weissella cibaria and Pediococcus pentosaceus reached 89.2 ± 4, 104.5 ± 15.3, 30.2 ± 4 and 181.5 ± 2.6 mV, respectively. W. cibaria showed the highest reducing activity and P. pentosaceus the lowest one. The maximal reduction rate was neither correlated with the highest acidification rate nor with the maximal growth rate. Nevertheless, the reduction rate shows a similar trend like the acidification rate during the time course of fermentation. The ORP changes occurred concomitantly with the acidification, and the acid production decreased after 2 h from the reducing step. These results showed the possibility to carry out ORP measurements in dough system. As strains exhibit very characteristic ORP curves, this parameter can be used as real-time control tool to monitor the time course of fermentation and metabolic activity. This enables an evidence-based determination of fermentation end and/or (intermediate) harvesting point, which is especially helpful in the development of new cereal fermentation types as in gluten-free sourdoughs.

All Solid State Nickel(II)‐Selective Potentiometric Sensor Based on an Upper Rim Substituted Calixarene

AbstractA new ionophore, i.e. p‐(2‐thiazolazo)calix[4]arene (I) has been explored for its selective behavior towards Ni(II) ions. A poly(vinyl chloride) based membrane containing (I) as an electroactive material along with sodiumtetraphenylborate (NaTPB), and nitrophenyloctyl ether in the ratio 10 : 100 : 3 : 150 (I:PVC:NaTPB:NPOE) (w/w) was used to fabricate an all solid state nickel(II)‐selective sensor. The developed sensor exhibited a working concentration range of 1.0×10−6–1.0×10−1 M, with a Nernstian slope of 28.9±1.0 mV/decade of activity and a response time of 10–15 s. This sensor shows a detection limit of 9.0×10−7 M. Its potential response remains unaffected of pH in the range 3.0–7.6, and the cell assembly could be used successfully in partially nonaqueous medium (up to 10 % v/v) without any significant change in the slope value or the working concentration range. The sensor worked satisfactorily for about ten weeks and exhibited excellent selectivity over a number of mono‐, bi‐, and tri‐valent cations including alkali, alkaline earth metal, and transition metal ions. It could be used as an indicator electrode for the end point determination in the potentiometric titration of nickel ions against ethylenediaminetetraacetic acid (EDTA) as well as for the determination of nickel ion concentration in real samples.

Mineralogical study and leaching behavior of a stabilized harbor sediment with hydraulic binder

The environmental assessment of potential effects of contaminated harbor sediments stabilized with hydraulic binders and the determination of remediation endpoints require the determination of pollutants leaching potentials. Moreover, little information about the speciation and mobility of inorganic contaminants in these specific solid matrices is available in the literature. The objective of this paper is to investigate the relationship between mineralogy and leachability of contaminants (copper, lead, and zinc) present in a French harbor sediment stabilized with quicklime and Portland cement. Batch equilibrium leaching tests at various pH, chemical analysis of leachates, and mineralogical studies (X-ray diffraction, scanning electron microscopy-energy dispersive spectroscopy, and diffuse reflectance infrared Fourier transform) have been combined in the present investigation. The acid neutralization capacity of the stabilized matrix studied is first controlled by the dissolution of portlandite (pH ~12), followed by the dissolution of C-S-H (pH ~11) and the dissolution of ettringite (pH ~10). Finally, a very high buffering capacity of this stabilized sediment is observed for pH values around 6. This equilibrium is mainly controlled by the dissolution of iron sulfides and carbonate minerals. Consequently, the mobilization of inorganic contaminants as a function of pH remains very low (<0.1 wt%) for pH values above 6 and significantly increases for pH below these values. This research confirms the importance of a combined methodology for the intrinsic characterization of potential mobilization of contaminants in a stabilized sediment and for a better understanding of geochemical processes that affect contaminant fate, transformation, and transport in the subsurface environment.

Robust reference intervals for Liver function test (LFT) analytes in newborns and infants

BackgroundReference intervals (RIs) are ranges of upper and lower limits of a given analyte which are used for a laboratory test to determine whether a disease is present or absent or to know if the patient is at risk for future disease states. In Ethiopia, a country with highly diversified population groups and geographical sites, there are no established RIs to metabolic analytes including the liver function test (LFT) analytes for the pediatric population though it has been known that liver function assessment in this population is vital as a result of varied vulnerability to both endogenous and xenobiotic substances.MethodsA cross sectional study was conducted in Tikur Anbessa Specialized Hospital (TASH) and Teklehaymanot Health Center (THC) from November 2010 to April 2011. 117 cord blood (from newborns) and venous blood samples (from infants) were collected and analyzed using HumaStar 300. All pre-analytical, analytical and post-analytical aspects were thoroughly controlled. A robust, CLSI/ IFCC recommended, method was used for the determination of upper and lower end points covering 95% of the reference values of each analyte with respective 90% CIs using MedCalc® software.ResultsCombined RIs for newborns and infants were established for albumin, AST, ALP, direct bilirubin and total bilirubin to be 3.88-5.82 g/dl, 16.1-55.4U/l, 130-831U/l, <0.41 mg/dl and <1.37 mg/dl respectively. But, separated RIs were indicated for ALT and GGT as 1.2-23.1U/l and 6.94-24.8U/l ALT; and 30.6-160.7U/L and 10–28.2U/l GGT for newborns and infants respectively. Some maternal and infantile factors were identified to affect the values of analytes.ConclusionAlmost all analytes were different from previously reported values for other target population of similar age group, kit insert values and adult values. So, interpretation of values of these analytes in newborns and infants of Ethiopian population sounds better to be performed by using such RIs taking the effect of some maternal and infantile factors in to account.

End point determination of blending process for trimebutine tablets using principle component analysis (PCA) and partial least squares (PLS) regression

This study showed near Infrared (NIR) and Raman spectroscopy with a multivariate calibration approach were very effective to determine blend uniformity end-point. A set of 36 trimebutine samples containing magnesium stearate, stearic acid, colloidal silicon oxide, talc as excipients (0.9%∼1.8%) was acquired from six positions during blending processing with U-type blender from 0 to 30 min. Principle component analysis (PCA) with NIR and Raman spectral data was used to confirm the end-point of blending. After 30 min, the scores of principle component (PC) 1 and principle component (PC) 2 for samples moved into one point, which clearly indicated the mixture of sample became homogenous. In addition, NIR and Raman spectroscopy has been applied to the quantitative analysis of 20 trimebutine samples containing 2∼40% in mixture granules, which divided into a calibration set of 15 samples and a prediction set of 5 samples for NIR spectral data. The standard error of calibration (SEC) and standard error of prediction (SEP) are 0.15% and 0.13%, respectively using NIR while SEC and SEP of 0.95% and 0.91% are obtained using Raman spectroscopy. The results showed the NIR and Raman spectroscopy with a multivariate calibration such as PCA and PLS provide the possibility of real time monitoring of homogeneity and content uniformity during blending process.

Exploring the effects of high shear blending on lactose and drug using fluidised bed elutriation

Powder formulations comprising inhalation grade lactose and a mimic drug (cholesterol) were prepared using a high shear blending process for which the total energy input could be quantified. The formulations were fluidised in a classic fluidised bed system, to determine whether blending-induced changes could be determined through either bulk fluidisation behaviour or the characteristics of elutriated fractions from the powder beds. The evolution of the fluidisation regime within the powder beds (Δ pressure vs. superficial gas velocity) and total mass of elutriated material were not sensitive measures to differentiate between blended and unblended samples. However, blended and unblended material could be distinguished by the size distributions of the elutriated fractions. The study also showed that there were no further changes in the size distribution of the elutriated fractions once a chemically homogenous mixture of lactose and drug had been produced. However, further blending beyond this ‘point of homogeneity’ continued to change the lactose particle size distribution of the bulk powder; this may have implications for blend end point determination for these types of formulation.

Health Evaluation of Experimental Laboratory Mice

Good science and good animal care go hand in hand. A sick or distressed animal does not produce the reliable results that a healthy and unstressed animal produces. This unit describes the essentials of assessing mouse health, colony health surveillance, common conditions, and determination of appropriate endpoints. Understanding the health and well-being of the mice used in research enables the investigator to optimize research results and animal care.

A Research Agenda for Helminth Diseases of Humans: Modelling for Control and Elimination

Mathematical modelling of helminth infections has the potential to inform policy and guide research for the control and elimination of human helminthiases. However, this potential, unlike in other parasitic and infectious diseases, has yet to be realised. To place contemporary efforts in a historical context, a summary of the development of mathematical models for helminthiases is presented. These efforts are discussed according to the role that models can play in furthering our understanding of parasite population biology and transmission dynamics, and the effect on such dynamics of control interventions, as well as in enabling estimation of directly unobservable parameters, exploration of transmission breakpoints, and investigation of evolutionary outcomes of control. The Disease Reference Group on Helminth Infections (DRG4), established in 2009 by the Special Programme for Research and Training in Tropical Diseases (TDR), was given the mandate to review helminthiases research and identify research priorities and gaps. A research and development agenda for helminthiasis modelling is proposed based on identified gaps that need to be addressed for models to become useful decision tools that can support research and control operations effectively. This agenda includes the use of models to estimate the impact of large-scale interventions on infection incidence; the design of sampling protocols for the monitoring and evaluation of integrated control programmes; the modelling of co-infections; the investigation of the dynamical relationship between infection and morbidity indicators; the improvement of analytical methods for the quantification of anthelmintic efficacy and resistance; the determination of programme endpoints; the linking of dynamical helminth models with helminth geostatistical mapping; and the investigation of the impact of climate change on human helminthiases. It is concluded that modelling should be embedded in helminth research, and in the planning, evaluation, and surveillance of interventions from the outset. Modellers should be essential members of interdisciplinary teams, propitiating a continuous dialogue with end users and stakeholders to reflect public health needs in the terrain, discuss the scope and limitations of models, and update biological assumptions and model outputs regularly. It is highlighted that to reach these goals, a collaborative framework must be developed for the collation, annotation, and sharing of databases from large-scale anthelmintic control programmes, and that helminth modellers should join efforts to tackle key questions in helminth epidemiology and control through the sharing of such databases, and by using diverse, yet complementary, modelling approaches.

A novel titration method based on fiber-optic refractive index sensing for the determination of deacetylation degree of chitosans

We describe a novel method for determining the degree of deacetylation (DD) of chitosans from fiber-optic measurements of refractive index. Theory analyses and the experimental setup of the method are introduced and discussed. The analytical performance of the method is described for the determination of alkaline titration end-points. Experimental results reveal that the equivalence point can be directly identified from the titration curve. The proposed method is simple, low-cost, accurate, reliable, and easy to operate for industrial application. The DD values of four chitosan samples obtained with this new method show good agreement with those yielded from 1H NMR. Such a mechanism of refractive-index monitor should open up a new application in the field of chitosanolytic enzymes, such as chitosanase, pectinase that are important in bioprocesses.