Rapid Colorimetric and Fluorometric Discrimination of Maleic Acid vs. Fumaric Acid and Detection of Maleic Acid in Food Additives

An anthracene thiazole based Schiff base L was synthesized and employed for fluorescence switch-on detection of maleic acid in aqueous DMSO. The non-fluorescent L (10-5 M) showed an instantaneous and selective fluorescence enhancement at 506 nm upon interaction with maleic acid (10-5 M). Other potential carboxylic acids (10-5 M), such as malic acid, citric acid, acetic acid, cinnamic acid, tartaric acid, succinic acid, fumaric acid, oxalic acid and malonic acid failed to alter the chromo-fluorogenic properties of L. Probe L can be employed to detect maleic acid down to 2.74 × 10-6 M. The probe L showed good linearity from 2.97 to 6.87 µM. Analytical utility of L was examined by detecting maleic acid in various food additives and drosophila larvae.

Using a mobile phone-based application as an adjunct to facilitate oral hygiene practices in children with Attention Deficit Hyperactivity Disorder (ADHD)

AIM

To evaluate the efficacy of a mobile phone application to facilitate oral hygiene practices in children with ADHD.

METHODS

This was a randomized controlled study that included 54 ADHD children after obtaining informed parental consent. The children were randomly divided into 2 groups; Group 1 (conventional) participants were instructed verbally as well as demonstrated the brushing technique on models. Group 2 (mobile phone application) participants were made to download and use the 'BRUSH DJ' app developed by Ben Underwood. At baseline, the oral hygiene index-simplified (OHI-S) [Greene and Vermillion, 1964] of each child was evaluated clinically and the parents were asked to fill a questionnaire regarding the oral hygiene practices followed by their child every day. At the end of the second, sixth, and twelfth week, the parents were asked to fill the same questionnaire in addition to the evaluation of the OHI-S index.

RESULTS

A significant difference was found in the brushing time, brushing frequency, and OHI-S index between group 1 and group 2 at the end of 12 weeks. (unpaired t-test, p<0.05)

CONCLUSION

The mobile phone application proved to be an effective tool in captivating the attention of these children and thus improving their oral health.

Preclinical Pharmacokinetic Study on Caffeine as an Excipient for Monoclonal Antibody Formulations

Caffeine is a novel excipient that effectively reduces viscosity of high concentration mAb formulations intended for subcutaneous (SQ) delivery. Two preclinical studies were conducted in rats to evaluate pharmacokinetic (PK) parameters of caffeine as well as its effects on the PK profile of a model mAb, namely ipilimumab. Results show that SQ absorption and elimination of caffeine was rapid, with the average Tmax of 0.4 h and T1/2 of 1.6 h, administered with or without ipilimumab. Furthermore, caffeine did not affect ipilimumab SQ PK profiles. Independent of caffeine concentration, ipilimumab serum T1/2 was between 2 and 3 days, Tmax was between 3 and 4 days and SQ bioavailability was about 64%. In addition, SQ injection of caffeine at different dose levels showed no irritation at the injection site or adverse effects. Results from the current PK studies warrant further development of caffeine as a viscosity reducing excipient for mAb SQ formulations.

Caffeine as a Viscosity Reducer for Highly Concentrated Monoclonal Antibody Solutions

Many monoclonal antibody (mAb) solutions exhibit high viscosity at elevated concentrations, which prevents manufacturing and injecting of concentrated mAb drug products at the small volumes needed for subcutaneous (SC) administration. Addition of excipients that interrupt intermolecular interactions is a common approach to reduce viscosity of high concentration mAb formulations. However, in some cases widely used excipients can fail to lower viscosity. Here, using infliximab and ipilimumab as model proteins, we show that caffeine effectively lowers the viscosity of both mAb formulations, whereas other common viscosity-reducing excipients, sodium chloride and arginine, do not. Furthermore, stability studies under accelerated conditions show that caffeine has no impact on stability of lyophilized infliximab or liquid ipilimumab formulations. In addition, presence of caffeine in the formulations does not affect in vitro bioactivities of infliximab or ipilimumab. Results from this study suggest that caffeine could be a useful viscosity reducing agent that complements other traditional excipients and provides viscosity reduction to a wider range of mAb drug products.

Bariatric and Metabolic Endoscopy: A New Paradigm

The prevalence of obesity, type 2 diabetes mellitus, and metabolic syndromes is increasing globally. Minimally invasive metabobariatric (MB) endoscopic therapies are adjunct treatments that can potentially bridge the gap between surgical interventions and medical therapy. A growing number of MB techniques are becoming available, allowing for more personalized and patient-targeted treatment options for specific disease states. MB techniques are less invasive than surgery and can precisely target different parts of the gastrointestinal tract that may be responsible for the pathophysiology of obesity and metabolic syndromes such as type 2 diabetes mellitus. These alternatives should be selected on an individualized patient basis to balance the expected clinical outcomes and desired anatomical targets with the level of invasiveness and degree of acceptable risk. Each MB intervention presents great flexibility allowing for a tailored intervention and different levels of patient engagement. Patient awareness and motivation are essential to avoid therapy withdrawal and failure. Differences between MB procedures in terms of weight loss and metabolic benefit will be discussed in this review, along with the insights on clinical decision-making processes to evaluate the potential of further evolution and growth of bariatric and metabolic endoscopy.

Challenges for design of aggregation-resistant variants of granulocyte colony-stimulating factor

Non-native protein aggregation is a long-standing issue in pharmaceutical biotechnology. A rational design approach was used in order to identify variants of recombinant human granulocyte colony-stimulating factor (rhG-CSF) with lower aggregation propensity at solution conditions that are typical of commercial formulation. The approach used aggregation-prone-region (APR) predictors to select single amino acid substitutions that were predicted to decrease intrinsic aggregation propensity (IAP). The results of static light scattering temperature-ramps and chemical unfolding experiments demonstrated that none of the selected variants exhibited improved aggregation resistance, and the apparent conformational stability of each variant was lower than that of WT. Aggregation studies under partly denaturing conditions suggested that the IAP of at least one variant remained unaltered. Overall, this study highlights a general challenge in designing aggregation resistance for proteins, due to the need to accurately predict both APRs and conformational stability.

COVID-19 infection in patients with intestinal failure: UK experience

BACKGROUND

The direct effect of the coronavirus disease 2019 (COVID-19) pandemic on patients with intestinal failure (IF) has not been described.

METHODS

We conducted a nationwide study of UK IF centers to evaluate the infection rates, presentations, and outcomes in patients with types 2 and 3 IF.

RESULTS

A total of 45 patients with IF contracted COVID-19 between March and August 2020; this included 26 of 2191 (1.2%) home parenteral nutrition (HPN)-dependent adults and 19 of 298 (6.4%) adults hospitalized with type 2 IF. The proportion of patients receiving nursing care for HPN administration was higher in those with community-acquired COVID-19 (66.7%) than the proportion in the entire HPN cohort (26.1%; P < .01). Two HPN-dependent and 1 hospitalized patient with type 2 IF died as a direct consequence of the virus (6.7% of 45 patients with types 2 or 3 infected).

CONCLUSION

This is the first study to describe the outcomes of COVID-19 in a large cohort of patients requiring long-term PN. Methods to reduce hospital and community nosocomial spread would likely be beneficial.

Language matters. Addressing the use of language in the care of people with diabetes: position statement of the English Advisory Group

The language used by healthcare professionals can have a profound impact on how people living with diabetes, and those who care for them, experience their condition and feel about living with it day-to-day. At its best, good use of language, both verbal and written, can lower anxiety, build confidence, educate and help to improve self-care. Conversely, poor communication can be stigmatizing, hurtful and undermining of self-care and can have a detrimental effect on clinical outcomes. The language used in the care of those with diabetes has the power to reinforce negative stereotypes, but it also has the power to promote positive ones. The use of language is controversial and has many perspectives. The development of this position statement aimed to take account of these as well as the current evidence base. A working group, representing people with diabetes and key organizations with an interest in the care of people with diabetes, was established to review the use of language. The work of this group has culminated in this position statement for England. It follows the contribution of Australia and the USA to this important international debate. The group has set out practical examples of language that will encourage positive interactions with those living with diabetes and subsequently promote positive outcomes. These examples are based on a review of the evidence and are supported by a simple set of principles.

Outcomes in Patient Undergoing Maxillectomy for Squamous Cancer Invading Maxilla in a Rural Tertiary Care Institute in Socioeconomic Poor Group of Patients

Background: Oral cancer accounts for more than 250,000 new cases of cancer in India. Oral cancer combining all sites of cancer in oral cavity is the single commonest cancer in males in India. Oral cancer involving upper alveolus and primary maxillary sinus tumors are a surgical challenge due to the complex surgery and rehabilitation. Aim: Optimal treatment strategy for treatment of squamous cancer invading maxillary sinus. Methods: This is a retrospective study of clinicopathological features, treatment, rehabilitation and outcome of all patients who underwent surgical treatment of tumor invading maxillary sinus over a period of 30 months in a rural cancer hospital. Results: Out of a total of 47 patients, 26 (55.3%) were males and 21 (44.7%) were females. Median age was 56 year with youngest patient of 23 year and oldest 88 year old. Primary maxillary sinus cancers were 19.1%, palatal tumors were 10.6% and 70.3% were buccal mucosa and upper alveolus cancers. Early cancers were 51% and locally advanced were 49%. Total maxillectomy was performed in 59.6%, partial maxillectomy in 34.1% and extended maxillectomy in 6.3% of the patients. Histology was squamous carcinoma in all patients and 85.1% were grade 2. Peripheral neural invasion was present in 14.9%, lympho-vascular emboli in 23.4%, and surgical margins were positive in 10% of the patients. Eighty percent patients underwent reconstruction by free microvascular flap. Fifty-one percent patients received postoperative chemoradiotherapy while 25.5% received only radiotherapy and 19.1% received no adjuvant treatment. At a mean follow-up of 11 months 74.5% patients are alive. Good speech was achieved in 70% and intelligible speech in 17% of the patients, while 12.8% were not able to speak. Solid food swallowing was achieved in 36.2%, semisolid in 27.6%, liquid in 19.1% of the patients and 12.8% remained on nasogastric tube feeds. Conclusion: Surgical resection with reconstruction by microvascular flap and postsurgical chemoradiotherapy in locally advanced cancers is key for improved survival and successful rehabilitation in cancer invading maxilla.

Dynamics of virus-specific T cell immunity in pediatric liver transplant recipients

Immunosuppression following solid organ transplantation (SOT) has a deleterious effect on cellular immunity leading to frequent and prolonged viral infections. To better understand the relationship between posttransplant immunosuppression and circulating virus-specific T cells, we prospectively monitored the frequency and function of T cells directed to a range of latent (CMV, EBV, HHV6, BK) and lytic (AdV) viruses in 16 children undergoing liver transplantation for up to 1 year posttransplant. Following transplant, there was an immediate decline in circulating virus-specific T cells, which recovered posttransplant, coincident with the introduction and subsequent routine tapering of immunosuppression. Furthermore, 12 of 14 infections/reactivations that occurred posttransplant were successfully controlled with immunosuppression reduction (and/or antiviral use) and in all cases we detected a temporal increase in the circulating frequency of virus-specific T cells directed against the infecting virus, which was absent in 2 cases where infections remained uncontrolled by the end of follow-up. Our study illustrates the dynamic changes in virus-specific T cells that occur in children following liver transplantation, driven both by active viral replication and modulation of immunosuppression.

Pontomesencephalic Atrophy and Postural Instability in Wilson Disease

BACKGROUND AND PURPOSE

The MR Parkinsonism index helps in differentiating progressive supranuclear palsy from Parkinson disease and multisystem atrophy. Pontomesencephalic involvement is common in neurologic Wilson disease, but there is no prior study evaluating the MR Parkinsonism index and its indices in Wilson disease. We report the MR Parkinsonism index and its indices in Wilson disease and correlate these changes with clinical severity and postural reflex.

MATERIALS AND METHODS

Thirteen individuals with neurologic Wilson disease were included, and their clinical details, including neurologic severity, postural reflex abnormality, and location of signal changes on MR imaging, were noted. The 3D BRAVO T1 sequence was used for measurement of the MR Parkinsonism index and its indices. The MR Parkinsonism index and its indices were also obtained in 6 age- and sex-matched controls. The morphometric parameters in Wilson disease were compared with those in with healthy controls and among the patients with and without abnormal postural reflex.

RESULTS

The midbrain area was reduced in patients with Wilson disease compared with controls (112.08 ± 27.94 versus 171.95 ± 23.66 mm², P = .002). The patients with an abnormal postural reflex had an increased MR Parkinsonism index and pons-to-midbrain ratio compared with controls, whereas these parameters were equivalent in patients with normal postural reflex and controls. The patients with abnormal postural reflex had more severe illness, evidenced by higher Burke-Fahn-Marsden scores (51.0 ± 32.27 versus 13.75 ± 12.37, P = .04) and neurologic severity grades (2.57 ± 0.53 versus 1.67 ± 0.82, P = .04).

CONCLUSIONS

An increase in the MR Parkinsonism index in Wilson disease is mainly due to midbrain atrophy and it correlates with neurologic severity and abnormal postural reflex.

Influence of Different Substrates in Detoxification Activity of Adult Rat Hepatocytes in Long-Term Culture: Implications for Transplantation

Substrates used to immobilize hepatocytes for transplantation govern attachment and long-term metabolic activity of these cells. The choice of these substrates is based on the familiarity with proteinaceous materials that are constituents of the extracellular matrix. The use of substrates that recognize carbohydrates on the cell surface may provide an alternative method to attach adult mammalian hepatocytes.

In this study, immobilized lectins on tissue culture plasticware were used to support hepatocyte attachment. Long-term cultures with these substrates were compared with control cultures seeded on a mixture of collagen types I and III (Vitrogen).

To evaluate the attachment efficiency and long-term maintenance of diazepam metabolic activity of hepatocytes seeded on different commercially available plasticware, four different types of polymers (supplied as 60-mm dishes) were tested. Diazepam, a benzodiazepine metabolized by the P450 intracytoplasmic pathway, is associated with a synaptic receptor (GABA-benzodiazepine receptor) which plays an important role in hepatic coma.

Polymethylpentene, a derivative of polypropylene treated by plasma discharge, was the best polymer to maintain P450 phenotypic expression, although other polymers provided similar cell attachment efficiencies. The amounts of adsorbed concanavalin A, Arachis hypogaea (peanut), Lens culinaris, and Pisum sativum agglutinin correlate with the percentage values of hepatocyte attachment. Cell attachment to wheat germ agglutinin increased with increased lectin concentrations in spite of constant amounts of adsorbed lectin, whereas hepatocyte attachment to Bandieraea simplicifolia agglutinin was lower and did not change at different lectin concentrations. Long-term cultures of hepatocytes seeded on Vitrogen, concanavalin A, or wheat germ agglutinin showed similar diazepam metabolic activities up to the 10th day, but by day 25, cells seeded on Vitrogen metabolized diazepam at higher values.

This study showed that a polymer used for the manufacture of tissue culture plasticware, which permits a better exchange of gases, contributes to the long-term expression of P450 activity. Lectins proved to be nontoxic for hepatocyte survival, maintained hepatocyte viability, and can be used as an alternative substrate to immobilize hepatocytes to be transplanted in animal models of acute or chronic liver failure.

Functional Recovery of Porcine Hepatocytes after Hypothermic or Cryogenic Preservation for Liver Support Systems

The provision of an immediate supply of isolated porcine hepatocytes for artificial liver support requires preservation techniques that will allow maintenance of cell viability and detoxification functions. By means of a simple and cost-effective cryopreservation system, porcine hepatocytes can be available for both local and distant medical treatment facilities. Additionally, cryopreservation provides an adequate period for quality control testing to be completed prior to use of any specific cell lot. We are reporting a dual approach, namely the preservation of porcine hepatocytes, at 4°C and at −196°C in liquid nitrogen (LN2). Using a combination of cryoprotectant agents with Chee's modified Eagle's culture media (CEM), collagenase isolated hepatocytes stored at 4°C for 24 h maintained 80% of the initial diazepam metabolism measured in freshly isolated cells and nearly 100% of initial function was preserved in hepatocytes stored up to 6 mo at -196°C. University of Wisconsin solution (UW) was also tested and while adequate for 4°C storage, it certainly did not match the performance of the CEM formulations for preservation of metabolic function of cells stored in liquid nitrogen. Based on our results of viability and detoxification function the combination of CEM with DMSO, polyethylene glycol and serum provided optimal protection for LN2 frozen cells. Other findings in these studies underlined the importance of the gradual introduction of DMSO in the prefreezing process, the period of osmotic equilibration, and the rapid postthaw withdrawal of this agent to minimize cytotoxic effects at these critical stages. Our freezing methodology provides the foundation for further technological developments in the cryopreservation of the large numbers of cells (billions) that are necessary for extracorporeal liver assist devices.

Isolation and Culture of Porcine Hepatocytes for Artificial Liver Support

The primary requirement of cells in a liver support system is the preservation of the in vivo metabolic functions that prevent or decrease the progress of hepatic encephalopathy (HE) by providing interim support to liver failure patients. While rodent hepatocytes offer a model for liver assist device (LAD) research, their limited number per animal prohibits direct scale up to human devices. Healthy human liver cells are seldom available in adequate numbers to support clinical LAD use; consequently, a large animal source of liver cells is needed. The study presented here explored the potential of porcine hepatocytes to proliferate and maintain metabolic function in vitro. Porcine hepatocytes were isolated from ~12 kg swine by a modification of Seglen's method. Hepatocytes cultured up to 10 days were shown to metabolize ammonia and maintain both Phase I and II detoxification functions. In addition, the cultures showed proliferative activity both as an increase in total protein content and by thymidine incorporation. Immunocytochemical staining identified cell proliferation through Day 4 to be primarily hepatocytes while Days 6 and 10 showed nonparenchymal cells to be increasing. The detoxification functions measured showed peak activity on Day 4 and gradually declined through Day 10. The ability of porcine hepatocytes to proliferate and maintain a diversity of hepatic functions in culture strongly suggests their potential for use as the biological component of artificial LADs.

Single point mutation detection in living cancer cells by far-red emitting PNA-FIT probes

Peptide nucleic acid bis-quinoline conjugates are reported as attractive far-red emitting probes that detect mutated mRNA in living cells at SNP resolution.

Food image-induced brain activation is not diminished by insulin infusion

Background/Objective

The obesity epidemic appears to be driven in large part by our modern environment inundated by food cues, which may influence our desire to eat. While insulin decreases food intake in both animals and humans, the effect of insulin on motivation for food in the presence of food cues is not known. Therefore, the aim of this study was to evaluate the effect of an intravenous insulin infusion on the brain response to visual food cues, hunger and food craving in non-obese human subjects.

Subjects/Methods

Thirty-four right-handed healthy non-obese subjects (19F/15M, age: 29±8 yrs.; BMI: 23.1±2.1 kg/m2) were divided in two groups matched by age, and BMI: the Insulin Group (18 subjects) underwent a hyperinsulinemic-euglycemic-clamp, and the control group (16 subjects) received an intravenous saline infusion, while viewing high and low-calorie food and non-food pictures during a functional MRI scan. Motivation for food was determined via analogue scales for hunger, wanting and liking ratings.

Results

Food images induced brain responses in the hypothalamus, striatum, amygdala, insula, ventromedial prefrontal cortex (PFC), dorsolateral PFC, and occipital lobe (whole brain correction, P<0.05). Wanting (P<0.001) and liking (P<0.001) ratings were significantly higher for the food than the non-food images, but not different between insulin and saline infusion groups. Hunger ratings increased throughout the MRI scan and correlated with preference for high-calorie food pictures (r=0.70; P<0.001). However neither brain activity nor food craving were affected by hyperinsulinemia or hormonal status (leptin and ghrelin levels) (P=NS).

Conclusion

Our data demonstrate that visual food cues induce a strong response in motivation/reward and cognitive-executive control brain regions in non-obese subjects, but that these responses are not diminished by hyperinsulinemia per se. These findings suggest that our modern food cue saturated environment may be sufficient to overpower homeostatic hormonal signals, and thus contribute to the current obesity epidemic.

Chaperonin-Based Biolayer Interferometry To Assess the Kinetic Stability of Metastable, Aggregation-Prone Proteins

Stabilizing the folded state of metastable and/or aggregation-prone proteins through exogenous ligand binding is an appealing strategy for decreasing disease pathologies caused by protein folding defects or deleterious kinetic transitions. Current methods of examining binding of a ligand to these marginally stable native states are limited because protein aggregation typically interferes with analysis. Here, we describe a rapid method for assessing the kinetic stability of folded proteins and monitoring the effects of ligand stabilization for both intrinsically stable proteins (monomers, oligomers, and multidomain proteins) and metastable proteins (e.g., low Tm) that uses a new GroEL chaperonin-based biolayer interferometry (BLI) denaturant pulse platform. A kinetically controlled denaturation isotherm is generated by exposing a target protein, immobilized on a BLI biosensor, to increasing denaturant concentrations (urea or GuHCl) in a pulsatile manner to induce partial or complete unfolding of the attached protein population. Following the rapid removal of the denaturant, the extent of hydrophobic unfolded/partially folded species that remains is detected by an increased level of GroEL binding. Because this kinetic denaturant pulse is brief, the amplitude of binding of GroEL to the immobilized protein depends on the duration of the exposure to the denaturant, the concentration of the denaturant, wash times, and the underlying protein unfolding-refolding kinetics; fixing all other parameters and plotting the GroEL binding amplitude versus denaturant pulse concentration result in a kinetically controlled denaturation isotherm. When folding osmolytes or stabilizing ligands are added to the immobilized target proteins before and during the denaturant pulse, the diminished population of unfolded/partially folded protein manifests as a decreased level of GroEL binding and/or a marked shift in these kinetically controlled denaturation profiles to higher denaturant concentrations. This particular platform approach can be used to identify small molecules and/or solution conditions that can stabilize or destabilize thermally stable proteins, multidomain proteins, oligomeric proteins, and, most importantly, aggregation-prone metastable proteins.

Quantitative Evaluation of Macrophage Expression Using CD68 in Oral Submucous Fibrosis: An Immunohistochemical Study

BACKGROUND

Macrophages are important cells for the innate immunity. Circulating monocytes are attracted to tissues by chemotactic factors and become macrophages under the influence of their microenvironment. Several studies suggested that local and systemic upregulation of fibrogenic cytokines and downregulation of antifibrotic cytokine are central to the pathogenesis of oral submucous fibrosis (OSMF). Currently, there have been no attempts made to elucidate the presence and role of macrophages in OSMF.

AIM

Our aim was to study the expression of CD68 in OSMF patients and to investigate the possible correlation of macrophages using CD68 in various histopathological grades of OSMF.

SUBJECTS AND METHODS

A prospective case-control study which included 40 patients was conducted after obtaining informed consent and Ethical Committee clearance. Ten cases were normal control and thirty cases had OSMF. Biopsy was performed and a quantitative study of macrophages was done using CD68 antigen and was immunohistochemically localized. Statistical analysis was carried out using the Statistical Package for Social Sciences (SPSS) 17.0 version (SPSS Inc., Chicago, IL, USA).

RESULTS

OSMF was observed in male patients of a younger age group. The macrophage number in the patients of intermediate and advanced stage of OSMF was higher than that of the controls which was statistically significant (P < 0.05).

CONCLUSION

The findings of this study suggest that CD68 plays a vital role in the pathogenesis of OSMF and can be regarded as a useful marker for assessing the progress of the disease.

Probing the kinetic stabilities of Friedreich's ataxia clinical variants using a solid phase GroEL chaperonin capture platform

Numerous human diseases are caused by protein folding defects where the protein may become more susceptible to degradation or aggregation. Aberrant protein folding can affect the kinetic stability of the proteins even if these proteins appear to be soluble in vivo. Experimental discrimination between functional properly folded and misfolded nonfunctional conformers is not always straightforward at near physiological conditions. The differences in the kinetic behavior of two initially folded frataxin clinical variants were examined using a high affinity chaperonin kinetic trap approach at 25 °C. The kinetically stable wild type frataxin (FXN) shows no visible partitioning onto the chaperonin. In contrast, the clinical variants FXN-p.Asp122Tyr and FXN-p.Ile154Phe kinetically populate partial folded forms that tightly bind the GroEL chaperonin platform. The initially soluble FXN-p.Ile154Phe variant partitions onto GroEL more rapidly and is more kinetically liable. These differences in kinetic stability were confirmed using differential scanning fluorimetry. The kinetic and aggregation stability differences of these variants may lead to the distinct functional impairments described in Friedreich's ataxia, the neurodegenerative disease associated to frataxin functional deficiency. This chaperonin platform approach may be useful for identifying small molecule stabilizers since stabilizing ligands to frataxin variants should lead to a concomitant decrease in chaperonin binding.

Probing structurally altered and aggregated states of therapeutically relevant proteins using GroEL coupled to bio-layer interferometry

The ability of a GroEL-based bio-layer interferometry (BLI) assay to detect structurally altered and/or aggregated species of pharmaceutically relevant proteins is demonstrated. Assay development included optimizing biotinylated-GroEL immobilization to streptavidin biosensors, combined with biophysical and activity measurements showing native and biotinylated GroEL are both stable and active. First, acidic fibroblast growth factor (FGF-1) was incubated under conditions known to promote (40°C) and inhibit (heparin addition) molten globule formation. Heat exposed (40°C) FGF-1 exhibited binding to GroEL-biosensors, which was significantly diminished in the presence of heparin. Second, a polyclonal human IgG solution containing 6-8% non-native dimer showed an increase in higher molecular weight aggregates upon heating by size exclusion chromatography (SEC). The poly IgG solution displayed binding to GroEL-biosensors initially with progressively increased binding upon heating. Enriched preparations of the IgG dimers or monomers showed significant binding to GroEL-biosensors. Finally, a thermally treated IgG1 monoclonal antibody (mAb) solution also demonstrated increased GroEL-biosensor binding, but with different kinetics. The bound complexes could be partially to fully dissociated after ATP addition (i.e., specific GroEL binding) depending on the protein, environmental stress, and the assay's experimental conditions. Transmission electron microscopy (TEM) images of GroEL-mAb complexes, released from the biosensor, also confirmed interaction of bound complexes at the GroEL binding site with heat-stressed mAb. Results indicate that the GroEL-biosensor-BLI method can detect conformationally altered and/or early aggregation states of proteins, and may potentially be useful as a rapid, stability-indicating biosensor assay for monitoring the structural integrity and physical stability of therapeutic protein candidates.

Monitoring the kinetics of the pH-driven transition of the anthrax toxin prepore to the pore by biolayer interferometry and surface plasmon resonance

Domain 2 of the anthrax protective antigen (PA) prepore heptamer unfolds and refolds during endosome acidification to generate an extended 100 Å β barrel pore that inserts into the endosomal membrane. The PA pore facilitates the pH-dependent unfolding and translocation of bound toxin enzymic components, lethal factor (LF) and/or edema factor, from the endosome to the cytoplasm. We constructed immobilized complexes of the prepore with the PA-binding domain of LF (LFN) to monitor the real-time prepore to pore kinetic transition using surface plasmon resonance and biolayer interferometry (BLI). The kinetics of this transition increased as the solution pH was decreased from 7.5 to 5.0, mirroring acidification of the endosome. Once it had undergone the transition, the LFN-PA pore complex was removed from the BLI biosensor tip and deposited onto electron microscopy grids, where PA pore formation was confirmed by negative stain electron microscopy. When the soluble receptor domain (ANTRX2/CMG2) binds the immobilized PA prepore, the transition to the pore state was observed only after the pH was lowered to early (pH 5.5) or late (pH 5.0) endosomal pH conditions. Once the pore formed, the soluble receptor readily dissociated from the PA pore. Separate binding experiments with immobilized PA pores and the soluble receptor indicate that the receptor has a weakened propensity to bind to the transitioned pore. This immobilized anthrax toxin platform can be used to identify or validate potential antimicrobial lead compounds capable of regulating and/or inhibiting anthrax toxin complex formation or pore transitions.

Distribution of hydro-biological parameters in coastal waters off Rushikulya Estuary, East Coast of India: a premonsoon case study

The hydro-biological parameters of coastal waters off Rushikulya estuary was investigated during premonsoon 2011. Important hydro-biological parameters such as water temperature, salinity, pH, DO, NO2, NO3, NH4, PO4, SiO4, TSM, Chl-a, phytoplankton and zooplankton were measured during the present study. Temperature established a strong positive correlation with salinity and pH during the present study. Chl-a found in positive relation with NO3, SiO, and TSM. Analysis of variance revealed significant monthly variation in pH, salinity and TSM. Significant station wise variation was observed in DO and most of the nutrients i.e., NO3, NH4, PO4, SiO4. A total of 119 species of phytoplankton were identified of which 84 species are of diatoms, 22 species of dinoflagellates, 7 species of green algae, 5 species of cyanobacteria (blue green algae) and 1 species of cocolithophore. Phytoplankton abundance varied between 25543 (Nos. L(-1)) and 36309 (Nos. L(-1)). Diatoms dominated the phytoplankton community followed by dinoflagellates in all the months. Diatoms contributed to 82-89% of the total phytoplankton population density whereas dinoflagellates contributed to 6-12%. The regression between Chl-a and phytoplankton abundance resulted with weak relation (R(2) = 0.042). Zooplankton fauna composed of 134 species of holoplankton and 20 types of meroplankton were encountered during the study period. Zooplankton population dominated by copepod during all months and accounted for 74 to 85% to the total zooplankton. The population density ranged from 6959 to 35869 Nos./10 m(3). Analysis of variance explained no significant variation in total zooplankton abundance and also for different groups of zooplankton.

Mathematical modelling to restore circulating IGF-1 concentrations in children with Crohn's disease-induced growth failure: a pharmacokinetic study

OBJECTIVES

Children with Crohn's disease grow poorly, and inflammation depresses the response of insulin-like growth factor-1 (IGF-1) to growth hormone. Correcting the inflammation normalises growth velocity; however, removing inflammation cannot be achieved in all children. Our lack of understanding of IGF-1 kinetics has hampered its use, particularly as high IGF-1 concentrations over long periods may predispose to colon cancer. We hypothesised that mathematical modelling of IGF-1 would define dosing regimes that return IGF-1 concentrations into the normal range, without reaching values that risk cancer.

DESIGN

Pharmacokinetic intervention study.

SETTING

Tertiary paediatric gastroenterology unit.

PARTICIPANTS

8 children (M:F; 4:4) entered the study. All completed: 5 South Asian British; 2 White British; 1 African British.

INCLUSION CRITERIA

Children over 10 years with active Crohn's disease (C reactive protein >10 mg/l or erythrocyte sedimentation rate >25 mm/h) and height velocity <-2 SD score.

EXCLUSION CRITERIA

closed epiphyses; corticosteroids within 3 months; neoplasia or known hypersensitivity to recombinant human IGF-1 (rhIGF-1).

INTERVENTIONS

Subcutaneous rhIGF-1 (120 μg/kg) per dose over two admissions: the first as a single dose and the second as twice daily doses over 5 days.

PRIMARY OUTCOME

Significant increase in circulating IGF-1.

SECONDARY OUTCOMES

Incidence of side effects of IGF-1. A mathematical model of circulating IGF-1 (Ac) was developed to include parameters of endogenous synthesis (Ksyn); exogenous uptake (Ka) from the subcutaneous dose (As): and IGF-1 clearance: where dAc/dt=Ksyn - Kout×Ac+Ka×As.

RESULTS

Subcutaneous IGF-1 increased concentrations, which were maintained on twice daily doses. In covariate analysis, disease activity reduced Ksyn (p<0.001). Optimal dosing was derived from least squares regression fitted to a dataset of 384 Crohn's patients, with model parameters assigned by simulation.

CONCLUSIONS

By using age, weight and disease activity scaling in IGF-1 dosing, over 95% of children will have normalised IGF-1 concentrations below +2.5 SDs of the normal population mean, a level not associated with cancer risk.

Conventional xylene and xylene-free methods for routine histopathological preparation of tissue sections

Xylene customarily has been used as a clearing agent for routine tissue processing. Because xylene is a relatively hazardous solvent, laboratories are under pressure to seek less toxic alternatives for routine use. We prepared 30 paired soft tissue specimens for routine histopathological evaluation using conventional xylene and xylene-free methods to evaluate and compare their efficacy for fixation, processing, embedding, staining and turnaround time. All specimens were measured before and after processing. Three pathologists evaluated and scored the histological sections. Tissue shrinkage was greater when using the xylene method compared to the xylene-free method. The quality of tissue sections including tissue architecture; quality of staining; preservation of epithelial, fibrous, glandular, muscle and adipose tissue; inflammatory cells; and vascular tissue was better after using the xylene method, but differences were not statistically significant. Xylene-free method produced adequate results that nearly equaled the xylene method. Added advantages included cost effectiveness, better working atmosphere and decreased toxicity.

In vitro up-regulation of HLA-G using dexamethasone and hydrocortisone in first-trimester trophoblast cells of women experiencing recurrent miscarriage

The trophoblast cells at the maternal-fetal interface express an unusual combination of human leukocyte antigen (HLA)-C, HLA-E and HLA-G. Altered expression of HLA-G on the extravillous cytotrophoblast has been implicated in the etiology of recurrent miscarriages (RMs). We have assessed HLA-G expression in extravillous cytotrophoblast in cell cultures prepared from RM patients and compared with those of first-trimester voluntarily terminated normal pregnancies (control). Glucocorticoids, dexamethasone and hydrocortisone were examined for their role in modulation of the HLA-G expression. HLA-G promoter and 3'UTR variants were investigated for their effect on the transcription of HLA-G. Cultured cytotrophoblast cells from the first-trimester RM patients were treated with dexamethasone and hydrocortisone (dose concentration 0-1000 ng/ml). HLA-G gene transcription was determined by semiquantitative and quantitative real-time polymerase chain reaction (RT-PCR), while protein expression was determined by a specific enzyme-linked immunosorbent assay (ELISA), flow cytometry and western blot analyses. HLA-G polymorphisms were detected by PCR and/or sequence-based typing. Low level of HLA-G was observed in untreated trophoblast cells obtained from RM patients as compared with controls. Upon treatment with glucocorticoids, the expression of HLA-G in these cells was up-regulated in a dose-dependent manner (P < 0.05), with no change in cellular proliferation and viability. There was no significant association between HLA-G polymorphism in RM patients and controls. HLA-G is minimally expressed in cultured trophoblast cells of RM patients. It can be up-regulated upon exposure with both dexamethasone and hydrocortisone. Glucocorticoids have the potential to modulate HLA-G expression in vitro, and can be further examined for their therapeutic applicability in RM.

The effects of anti-TNF-α treatment with adalimumab on growth in children with Crohn's disease (CD)

INTRODUCTION

Adalimumab is used to treat children with Crohn's disease (CD), but the effects of adalimumab on growth in CD have not been studied.

AIM

To study growth and disease activity over 12 months (6 months prior to (T-6), baseline (T0) and for 6 months following (T+6) adalimumab).

SUBJECTS AND METHODS

Growth and treatment details of 36 children (M: 22) who started adalimumab at a median (10th, 90th) age of 14.7 years (11.3, 16.8) were reviewed.

RESULTS

Of 36 cases, 28 (78%) went into remission. Overall 42% of children showed catch up growth, which was more likely in: (i) those who achieved remission (median change in height SDS (ΔHtSDS) increased from -0.2 (-0.9, 1.0) at T0 to 0.2 (-0.6, 1.6) at T+6, (p=0.007)), (ii) in those who were on immunosuppression ΔHtSDS increased from -0.2 (-0.9, 1.0) at T0 to 0.1 (-0.8, 1.3) at T+6, (p=0.03) and (iii) in those whose indication for using adalimumab therapy was an allergic reaction to infliximab, median ΔHtSDS increased significantly from -0.3 (-0.9, 1.0) at T0 to 0.3 (-0.5, 1.6) at T+6, (p=0.02). Median ΔHtSDS also increased from -0.4 (-0.8, 0.7) at T0 to 0.0 (-0.6, 1.6) at T+6, (p=0.04) in 15 children who were on prednisolone therapy when starting adalimumab.

CONCLUSION

Clinical response to adalimumab therapy is associated with an improvement in linear growth in a proportion of children with CD. Improved growth is more likely in patients entering remission and on immunosuppression but is not solely due to a steroid sparing effect.

Curative one-shot systemic virotherapy in murine myeloma

Current therapy for multiple myeloma is complex and prolonged. Antimyeloma drugs are combined in induction, consolidation and/or maintenance protocols to destroy bulky disease, then suppress or eradicate residual disease. Oncolytic viruses have the potential to mediate both tumor debulking and residual disease elimination, but this curative paradigm remains unproven. Here we engineered an oncolytic vesicular stomatitis virus to minimize its neurotoxicity, enhance induction of antimyeloma immunity, and facilitate noninvasive monitoring of its intratumoral spread. Using high resolution imaging, autoradiography and immunohistochemistry, we demonstrate that the intravenously administered virus extravasates from tumor blood vessels in immunocompetent myeloma-bearing mice, nucleating multiple intratumoral infectious centers which expand rapidly and necrose at their centers, ultimately coalescing to cause extensive tumor destruction. This oncolytic tumor debulking phase lasts only for 72 hours after virus administration, and is completed before antiviral antibodies become detectable in the bloodstream. Anti-myeloma T cells, cross-primed as the virus-infected cells provoke an antiviral immune response, then eliminate residual uninfected myeloma cells. The study establishes a curative oncolytic paradigm for multiple myeloma where direct tumor debulking and immune eradication of minimal disease are mediated by a single intravenous dose of a single therapeutic agent. Clinical translation is underway.