Approaching a discussion on the detachment of chlorpyrifos in contaminated water using different leaves and peels as bio adsorbents.

The emerging contaminant chlorpyrifos, an insecticide, is generally used in agricultural fields to control termites, ants, and mosquitoes for the proper growth of feed and food crops. Chlorpyrifos reaches water sources for multiple reasons, and people who use water from nearby sources is exposed to chlorpyrifos. Due to its overuse in modern agriculture, the level of chlorpyrifos in water has drastically grown. The present study aims to address the problem arising from the utilization of chlorpyrifos-contaminated water. Natural bioadsorbents Bael, Cauliflower, Guava leaves Watermelon, and lemon peel were employed to remove chlorpyrifos from contaminated water under specific conditions of various factors, such as initial adsorbate concentration, dose of bioadsorbent, contact time, pH, and temperature. Maximum removal efficiency of 77% was obtained with lemon peel. The maximum adsorption capacity (qe) was 6.37 mg g-1. The kinetic experiments revealed that the pseudo second order model (R2 = 0.997) provided a better explanation of the mechanism of sorption. The isotherm showed that chlorpyrifos adsorbed in lemon peel in a monolayer and was best suited by the Langmuir model (R2 = 0.993). The adsorption process was exothermic and spontaneous, according to thermodynamic data.

Optimization of ion exchange sigmoidal gradients using hybrid models: Implementation of quality by design in analytical method development.

Thorough product understanding is one of the basic tenets for successful implementation of Quality by Design (QbD). Complexity encountered in analytical characterization of biotech therapeutics such as monoclonal antibodies (mAbs) requires novel, simpler, and generic approaches towards product characterization. This paper presents a methodology for implementation of QbD for analytical method development. Optimization of an analytical cation exchange high performance liquid chromatography (CEX-HPLC) method utilizing a sigmoidal gradient has been performed using a hybrid mechanistic model that is based on Design of experiment (DOE) based studies. Since sigmodal gradients are much more complex than the traditional linear gradients and have a large number of input parameters (five) for optimization, the number of DOE experiments required for a full factorial design to estimate all the main effects as well as the interactions would be too large (243). To address this problem, a mechanistic model was used to simulate the analytical separation for the DOE and then the results were used to build an empirical model. The mechanistic model used in this work is a more versatile general rate model in combination of modified Langmuir binding kinetics. The modified Langmuir model is capable of modelling the impact of nonlinear changes in the concentration of the salt modifier. Further, to get the input and output profiles of mAb and salts/buffers, the HPLC system, consisting of the mixer, detectors, and tubing was modelled as a sequence of dispersed plug flow reactors and continuous stirred tank reactors (CSTR). The experimental work was limited to calibration of the HPLC system and finding the model parameters through three linear gradients. To simplify the optimization process, only three peaks in the centre of the profile (main product and the adjacent acidic and basic variants) were chosen to determine the final operating condition. The regression model made from the DoE data yielded a R2>0.97 which made it possible to predict and choose the design space where the optimal resolution between the acidic/main peaks and the basic/main peaks could be achieved (>1.2 and >2.5, respectively). The optimal operating condition was validated using experimental runs and was found to give the same resolution as what was predicted by the simulation. The proposed approach aims to significantly reduce the time required for method optimization as well as the extent of experimentation.

Opossum peptide that can neutralize rattlesnake venom is expressed in Escherichia coli.

An eleven amino acid ribosomal peptide was shown to completely neutralize Western Diamondback Rattlesnake (Crotalus atrox) venom in mice when a lethal dose of the venom was pre-incubated with the peptide prior to intravenous injection. We have expressed the peptide as a concatenated chain of peptides and cleaved them apart from an immobilized metal affinity column using a protease. After ultrafiltration steps, the mixture was shown to partially neutralize rattlesnake venom in mice. Preliminary experiments are described here that suggest a potential life-saving therapy could be developed. To date, no recombinant therapies targeting cytotoxic envenomation have been reported. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:81-86, 2017.

Aggregation Kinetics for IgG1-Based Monoclonal Antibody Therapeutics.

Monoclonal antibodies (mAbs) as a class of therapeutic molecules are finding an increasing demand in the biotechnology industry for the treatment of diseases like cancer and multiple sclerosis. A key challenge associated to successful commercialization of mAbs is that from the various physical and chemical instabilities that are inherent to these molecules. Out of all probable instabilities, aggregation of mAbs has been a major problem that has been associated with a change in the protein structure and is a hurdle in various upstream and downstream processes. It can stimulate immune response causing protein misfolding having deleterious and harmful effects inside a cell. Also, the extra cost incurred to remove aggregated mAbs from the rest of the batch is huge. Size exclusion chromatography (SEC) is a major technique for characterizing aggregation in mAbs where change in the aggregates' size over time is estimated. The current project is an attempt to understand the rate and mechanism of formation of higher order oligomers when subjected to different environmental conditions such as buffer type, temperature, pH, and salt concentration. The results will be useful in avoiding the product exposure to conditions that can induce aggregation during upstream, downstream, and storage process. Extended Lumry-Eyring model (ELE), Lumry-Eyring Native Polymerization model (LENP), and Finke-Watzky model (F-W) have been employed in this work to fit the aggregation experimental data and results are compared to find the best fit model for mAb aggregation to connect the theoretical dots with the reality.

Imaging in Sinonasal Inflammatory Disease.

While most patients with inflammatory rhinosinusitis are successfully diagnosed clinically, imaging is indicated in patients with recurrent or chronic sinusitis, atypical symptoms and complicated acute sinusitis. Non-enhanced high resolution, thin section computed tomography (CT) is the reference standard in evaluating such patients. It provides superb anatomical details and enables a fairly accurate diagnosis and delineation of the disease, addressing all concerns of the endoscopic surgeon prior to intervention. Contrast MR imaging is preferred for assessing intraorbital or intracranial complications. The radiologist must have a systematic approach to sinonasal CT and generate a clinically relevant report that impacts patient management.

Rapid analysis of charge variants of monoclonal antibodies using non-linear salt gradient in cation-exchange high performance liquid chromatography.

A method is proposed for rapid development of a short, analytical cation exchange high performance liquid chromatography method for analysis of charge heterogeneity in monoclonal antibody products. The parameters investigated and optimized include pH, shape of elution gradient and length of the column. It is found that the most important parameter for development of a shorter method is the choice of the shape of elution gradient. In this paper, we propose a step by step approach to develop a non-linear sigmoidal shape gradient for analysis of charge heterogeneity for two different monoclonal antibody products. The use of this gradient not only decreases the run time of the method to 4min against the conventional method that takes more than 40min but also the resolution is retained. Superiority of the phosphate gradient over sodium chloride gradient for elution of mAbs is also observed. The method has been successfully evaluated for specificity, sensitivity, linearity, limit of detection, and limit of quantification. Application of this method as a potential at-line process analytical technology tool has been suggested.

Role of organic modifier and gradient shape in RP-HPLC separation: analysis of GCSF variants.

Reversed-phase high-performance liquid chromatography (RP-HPLC) of therapeutic proteins continues to play a significant role in product characterization. This study focuses on two key aspects of HPLC method development, namely the selection of organic modifier and the gradient shape. Separation of granulocyte colony-stimulating factor variants is being used as a case study to illustrate these concepts. The results demonstrate that careful selection of a binary or ternary mixture of solvents with water is an important factor to be considered for achieving the desired resolution of closely related impurities. The resolution of different types of impurities has been shown to be selective toward the choice of eluent along with the ratio in which they are mixed. In addition, this study also presents a systematic approach for selection of gradient shape based on center point solvent composition, initial solvent composition and the steepness of the gradient. The approach proposed in this study was successfully used to reduce the time of analysis from 70 min for the pertinent European Pharmacopeia method to 15 min by using a solvent system with two organic modifiers (acetonitrile and methanol) along with a sigmoidal-shaped gradient.

Circular dichroism spectroscopy as a tool for monitoring aggregation in monoclonal antibody therapeutics.

Aggregation continues to be a critical quality attribute for a monoclonal antibody therapeutic product due to its perceived significant impact on immunogenicity. This paper aims to establish the versatility of circular dichorism (CD) spectroscopy toward understanding aggregation of monoclonal antibody (mAb) therapeutics. The first application involves the use of far-UV CD as a complementary analytical technique to size exclusion chromatography (SEC) for understanding protein aggregation. The second application uses thermal scanning CD as a high throughput screening tool for examining stability of a mAb therapeutic in various formulation and downstream buffers. For establishing far-UV CD as an orthogonal technique, a mAb was incubated in different downstream processing buffers and another mAb in formulation buffers, and they were analyzed by SEC and far-UV CD for aggregate content and conformational stability, respectively. To examine thermal scanning as a high throughput screening tool, ellipticity as a function of the temperature was measured at 218 nm from 20 to 90 °C. Far-UV CD was found to display high sensitivity toward early detection of conformational changes in mAb. CD measurements were also able to elucidate the different aggregation mechanisms. Furthermore, thermal stability scan allowed us to estimate T(onset) which has been found to correlate with aggregation induced by salt, low pH, and buffer species. T(onset) temperature from thermal scanning at 218 nm using CD was correlated successfully to aggregate content measured by SEC. Results from both the studies demonstrate the usefulness of CD for assessing stability of therapeutic proteins during process development, formulation development, and product characterization.

Avoiding antibody aggregation during processing: establishing hold times.

Aggregation of biotech products used therapeutically, such as antibodies, can contribute to potential immunogenicity of the product. Charge-based heterogeneities may also impact the safety and/or efficacy of a therapeutic. In this study, an approach based on empirical modeling and least squares regression is suggested for establishing hold times for process intermediates during production of monoclonal antibody (Mab) therapeutics. Two immunoglobulins were analyzed with respect to aggregation and charge heterogeneity in buffer conditions that are typically used during downstream processing of Mab products. Size exclusion chromatography, ion exchange chromatography (IEC), and circular dichroism were used. We found that aggregation primarily occurs at pH 3 (buffers used in affinity chromatography) and is higher in citrate buffer compared to acetate and glycine buffers. Aggregation is minimal in buffers used in anion exchange chromatography (Tris-HCl buffer at pH 7.2 and 8) and in cation exchange chromatography (citrate buffer at pH 6, acetate buffer at pH 6, and phosphate buffer at pH 6.5 and 7.5). The behavior is opposite in the case of charged heterogeneities (basic and acidic variants) as measured by IEC. The product is more susceptible to degradation at high pH than at low pH. The data presented here demonstrate that product stability can be a significant issue within the routinely used manufacturing conditions. We suggest that the approach presented needs to be adopted by all manufacturers to ensure product stability during processing.

A comparative study of visual reaction time in table tennis players and healthy controls.

UNLABELLED: Visual reaction time is time required to response to visual stimuli. The present study was conducted to measure visual reaction time in 209 subjects, 50 table tennis (TT) players and 159 healthy controls. METHODS: The visual reaction time was measured by the direct RT computerized software in healthy controls and table tennis players. Simple visual reaction time was measured. During the reaction time testing, visual stimuli were given for eighteen times and average reaction time was taken as the final reaction time. RESULTS: The study shows that table tennis players had faster reaction time than healthy controls. On multivariate analysis, it was found that TT players had 74.121 sec (95% CI 98.8 and 49.4 sec) faster reaction time compared to non-TT players of same age and BMI. Also playing TT has a profound influence on visual reaction time than BMI. CONCLUSION: Our study concluded that persons involved in sports are having good reaction time as compared to controls. These results support the view that playing of table tennis is beneficial to eye-hand reaction time, improve the concentration and alertness.

CT and MR imaging of the inner ear and brain in children with congenital sensorineural hearing loss.

Imaging plays an important role in the evaluation of congenital sensorineural hearing loss. In children who are candidates for cochlear implantation surgery, it provides vital preoperative information about the inner ear, the vestibulocochlear nerve, and the brain. High-resolution computed tomography (CT) and magnetic resonance (MR) imaging provide excellent delineation of the intricate anatomy of the inner ear: CT depicts the minute details of osseous structures, and MR imaging allows visualization of the fluid-filled spaces and the vestibulocochlear nerve. Together, these complementary modalities can aid decision making about the best management strategy by facilitating the identification and characterization of inner ear malformations and any associated neurologic abnormalities. It is important that the radiologist be familiar with the key imaging features when interpreting CT and MR images obtained in this patient group. A broad spectrum of inner ear malformations have been described and linked to developmental insults at different stages of embryogenesis, and various systems have been proposed for classifying them. In this article, these malformations are described by using classification systems used by otolaryngologists for ease of interpretation. The relevant normal anatomy and development of the inner ear are briefly surveyed, standard imaging protocols for studying the inner ear are reviewed, and the imaging appearances of frequently observed inner ear malformations are described and illustrated. The impact of the identification of these malformations and commonly associated brain abnormalities on clinical management and prognosis also is discussed.

Imaging in laryngeal cancers.

Imaging plays an important complementary role to clinical examination and endoscopic biopsy in the evaluation of laryngeal cancers. A vast majority of these cancers are squamous cell carcinomas (SCC). Cross-sectional imaging with contrast-enhanced computed tomography (CT) and magnetic resonance (MR) imaging allows excellent depiction of the intricate anatomy of the larynx and the characteristic patterns of submucosal tumor extension. CT, MRI and more recently PET-CT, also provide vital information about the status of cervical nodal disease, systemic metastases and any synchronous malignancies. Additionally, certain imaging-based parameters like tumor volume and cartilaginous abnormalities have been used to predict the success of primary radiotherapy or surgery in these patients. Integration of radiological findings with endoscopic evaluation greatly improves the pretherapeutic staging accuracy of laryngeal cancers, and significantly impacts the choice of management strategies in these patients. Imaging studies also help in the post-therapeutic surveillance and follow-up of patients with laryngeal cancers. In this article, we review the currently used laryngeal imaging techniques and protocols, the key anatomic structures relevant to tumor spread and the characteristic patterns of submucosal extension and invasion of laryngeal cancer. The role of CT, MRI and PET-CT in the evaluation of patients with laryngeal SCC and the impact of imaging findings on prognosis and clinical management is also discussed.

The congenital long QT syndrome.

OBJECTIVE: The long QT syndrome (LQTS) is a disorder of the electrical system of the heart, due to dysfunction of the ion channels and involving the repolarisation process. The inherited form occurs when there is a mutation in one of the genes which encode the making of a channel. Prolongation of the QT interval renders the patient vulnerable to an arrythmia called torsade de pointes, resulting in syncope and sudden death. METHODS: Three children with the congenital long QT syndrome presented to the pediatric department, one of them also having a 2:1 atrio-ventricular block. The parents and siblings of these children were screened for the long QT syndrome with an electrocardiogram. 2D echocardiography was done to rule out structural abnormalities and audiometry for deafness. RESULTS: Four family members were identified on screening to have LQTS. Propranolol was started on all children with LQTS. The child with heart block also received a pacemaker. LQTS must be considered in all patients presenting with syncope especially if associated with deafness and/or a family history of sudden deaths in infancy or childhood. CONCLUSION: The corrected QT interval must be determined in all children with heart block since the two conditions are often associated.