Reduced Graphene Oxide Electrolyte-Gated Transistor Immunosensor with Highly Selective Multiparametric Detection of Anti-Drug Antibodies

The advent of immunotherapies with biological drugs has revolutionized the treatment of cancers and auto-immune diseases. However, in some patients, the production of anti-drug antibodies (ADAs) hampers the drug efficacy. The concentration of ADAs is typically in the range of 1-10 pm; hence their immunodetection is challenging. ADAs toward Infliximab (IFX), a drug used to treat rheumatoid arthritis and other auto-immune diseases, are focussed. An ambipolar electrolyte-gated transistor (EGT) immunosensor is reported based on a reduced graphene oxide (rGO) channel and IFX bound to the gate electrode as the specific probe. The rGO-EGTs are easy to fabricate and exhibit low voltage operations (≤ 0.3 V), a robust response within 15 min, and ultra-high sensitivity (10 am limit of detection). A multiparametric analysis of the whole rGO-EGT transfer curves based on the type-I generalized extreme value distribution is proposed. It is demonstrated that it allows to selectively quantify ADAs also in the co-presence of its antagonist tumor necrosis factor alpha (TNF-α), the natural circulating target of IFX.

Coupling Capillary-Driven Microfluidics with Lateral Flow Immunoassay for Signal Enhancement

Microfluidics has emerged as a versatile technology that is applied to enhance the performance of analytical techniques, among others. Pursuing this, we present a capillary-driven microfluidic device that improves the sensitivity of lateral flow immunoassay rapid tests thanks to offering an automated washing step. A novel multilevel microfluidic chip was 3D-printed with a photocurable black resin, sealed by an optically clear pressure-sensitive adhesive, and linked to the lateral flow strip. To depict the efficacy of microfluidics and the washing step, cortisol was measured quantitatively within the proposed device. Measuring cortisol levels is a way to capture physiological stress responses. Among biofluids, saliva is less infectious and easier to sample than others. However, higher sensitivity is demanded because the salivary cortisol concentrations are much lower than in blood. We carried out a competitive lateral flow immunoassay protocol with the difference that the microfluidic device applies an automated washing step after the sample is drained downstream. It washes the trapped quantum-dot-labeled antibodies out from nitrocellulose, diminishing background noise as these are bonded to cortisols and not to the immobilized receptors. Fluorescence spectroscopy, as a high-precision analysis, was successfully applied to determine clinically relevant salivary cortisol concentrations within a buffer quantitatively. The microfluidic design relied on a 3D valve that avoids reagent cross-contamination. This cross-contamination could make the washing buffer impure and undesirably dilute the sample. The proposed device is cost-effective, self-powered, robust, and ideal for non-expert users.

Diffusion-free valve for preprogrammed immunoassay with capillary microfluidics

By manipulating the geometry and surface chemistry of microfluidic channels, capillary-driven microfluidics can move and stop fluids spontaneously without external instrumentation. Furthermore, complex microfluidic circuits can be preprogrammed by synchronizing the capillary pressures and encoding the surface tensions of microfluidic chips. A key component of these systems is the capillary valve. However, the main concern for these valves is the presence of unwanted diffusion during the valve loading and activation steps that can cause cross-contamination. In this study, we design and validate a novel diffusion-free capillary valve: the π-valve. This valve consists of a 3D structure and a void area. The void acts as a spacer between two fluids to avoid direct contact. When the valve is triggered, the air trapped within the void is displaced by pneumatic suction induced from the capillary flow downstream without introducing a gas bubble into the circuit. The proposed design eliminates diffusive mixing before valve activation. Numerical simulation is used to study the function and optimize the dimensions of the π-valve, and 3D printing is used to fabricate either the mould or the microfluidic chip. A comparison with a conventional valve (based on a constriction-expansion valve) demonstrates that the π-valve eliminates possible backflow into the valve and reduces the mixing and diffusion during the loading and trigger steps. As a proof-of-concept, this valve is successfully implemented in a capillary-driven circuit for the determination of benzodiazepine, achieving the successive release of 3 solutions in a 3D-printed microfluidic chip without external instrumentation. The results show a 40% increase in the fluorescence intensity using the π-valve relative to the conventional value. Overall, the π-valve prevents cross-contamination, minimizes sample use, and facilitates a sophisticated preprogrammed release of fluids, offering a promising tool for conducting automated immunoassays applicable at point-of-care testing.

Capillary-driven microfluidics: impacts of 3D manufacturing on bioanalytical devices

Over decades, decentralized diagnostics continues to move towards rapid and cost-effective testing at the point-of-care (POC). Although microfluidics has become a key enabling technology for POC testing, the need for robust peripheral equipment has been a key limiting factor in reaching an ideal device. Manufacturing technologies are now reaching a level of maturity that allows the definition of 3D features down to the sub-millimeter scale. Employing three-dimensional (3D) features and surface chemistry allows the possibility to pre-program sophisticated control of the capillary flow avoiding bulky peripheral equipment. By designing a sequence of steps, like elution of reagents, washing, mixing, and sensing, capillary valves have become a powerful tool for POC applications. These valves use capillary force to stop and then release flows within pre-programmed capillary circuits without any moving part. Without their 3D structure, the feasibility of creating pre-programmed bioanalytical devices would be nearly impossible. Besides, the advent of smart materials and their variety of surface properties permitted the unprecedented ability to fabricate reliable flow control with a range of capillary driving forces. The classification of such capillary elements is presented in two functional steps - stop and actuation. This review includes the advances in 3D microfabrication, design, and surface chemistry for manufacturing bioanalytical devices. These developments are critically reviewed, focusing on the process and considering phenomena such as timing, reproducibility, unwanted diffusion, and cross-contaminations.

Outreach, Screening, and Randomization of APOE ε4 Carriers into an Alzheimer's Prevention Trial: A global Perspective from the API Generation Program

BACKGROUND

Alzheimer's disease (AD) prevention trials require a large outreach and screening funnel to identify cognitively unimpaired adults who meet the study's inclusion criteria, such as certain clinical or demographic criteria, genetic risk factors, and/or biomarker evidence of the disease.

OBJECTIVES

Describe tactics and strategies to identify and enroll cognitively unimpaired adults with one (heterozygotes [HT]) or two (homozygotes [HM]) copies of the APOE ε4 allele, a genetic risk factor for dementia due to AD, into the Alzheimer's Prevention Initiative (API) Generation Program, the largest and only prevention trials for late onset AD using this enrichment technique.

DESIGN AND SETTING

The Generation Program was comprised of two global, randomized, double-blind, placebo-controlled, parallel group adaptive design with variable treatment duration clinical trials. Generation Study 1 randomized participants into one of two cohorts: Cohort 1 which evaluated CAD106 vs. placebo or Cohort 2 which evaluated umibecestat vs placebo. Generation Study 2 randomized participants into two doses of umibecestat vs. placebo. The Generation Program was terminated early in 2019, while enrollment was still occurring.

PARTICIPANTS

Both Generation Study 1 and Generation Study 2 enrolled cognitively unimpaired APOE ε4 HMs aged 60-75; Generation Study 2 also enrolled APOE ε4 HTs ages 60-75 with elevated brain amyloid.

METHODS AND MEASUREMENTS

Describe results of the centralized and localized outreach, recruitment, screening strategies and tactics as well as characteristics of sites successful at enrolling genetically eligible participants, with a particular focus on APOE ε4 HMs given the 2-3% prevalence of this genotype.

RESULTS

At the time the trial program was terminated, 35,333 individuals had consented to the optional prescreening ICF1a/ICFA and provided a sample of DNA for APOE genotyping, 1,138 APOE ε4 HMs consented to screening for Generation Study 1 (ICF1b), and 1,626 APOE ε4 carriers were randomized into either Generation Study 1 or Generation Study 2. Genetic testing registries, partnerships with genetic testing/counseling companies, and the optional prescreening ICF1a/ICFA were the most successful strategies for identifying genetically eligible participants for screening.

CONCLUSIONS

It is feasible to recruit, screen and randomize cognitively unimpaired APOE ε4 carriers, particularly APOE ε4 HMs for a global AD prevention trial. The Generation Program was on track to complete enrollment by end of 2019. Factors that were key to this success included: working with sites to develop customizable outreach, recruitment, and screening programs specific to their site needs, providing forums for sites to exchange best practices, and developing partnerships between the sponsor team and trial sites.

[Efficacy and safety of fingolimod in routine clinical practice in patients with relapsing-remitting multiple sclerosis in Spain: an intermediate analysis of the MS NEXT study]

INTRODUCTION

Fingolimod is a disease modifying therapies, which has showed clinical efficacy and an acceptable safety profile in clinical trials with relapsing-remitting multiple sclerosis (RRMS) patients.

AIM

To assess fingolimod effectiveness and safety in patients with RRMS in clinical practice.

PATIENTS AND METHODS

We present an interim analysis (July 2015) of MS NEXT, an observational, retrospective and multicenter study. 442 patients were included (mean age: 41 ± 9 years; median baseline EDSS: 3.0; 70% female; 284 previously treated with first-line disease modifying therapies, 139 with natalizumab and 19 without a previous treatment; mean fingolimod treatment duration: 25 ± 9 months) treated with fingolimod from November 2011 and with at least 12 months follow-up. 56 neurology-unit Spanish hospitals enrolled patients. Basal clinical and demographic data were recorded. Relapses, EDSS scores and radiological activity were recorded at baseline and annually. Adverse events were also recorded during the follow-up period.

RESULTS

After two years of follow-up: annual relapse rates decreased by 76%, the proportion of relapse-free patients was 67%, of disability progression-free patients confirmed at 3 months was 91%, of relapse and disability progression-free patients was 63%, of radiological activity-free patients was 50%, and the proportion of relapse, disability progression and radiological activity-free patients was 35%. Only 3.9% of patients discontinued fingolimod permanently during the first year of treatment.

CONCLUSIONS

In this interim analysis, most of patients treated with fingolimod in clinical practice had a controlled clinical disease activity, stable disability progression and high persistency.

From high doses of oral rivastigmine to transdermal rivastigmine patches: user experience and satisfaction among caregivers of patients with mild to moderate Alzheimer disease

INTRODUCTION

Rivastigmine, a treatment for mild to moderate Alzheimer disease (AD), is the first cholinesterase inhibitor to be available in the transdermal format. We aim to describe user experience and satisfaction with the rivastigmine patch, as well as any clinical changes perceived in patients.

METHODS

Observational, cross-sectional, multicentre study with 239 investigators and 1851 informal caregivers of patients with mild to moderate AD. Patients were treated with transdermal rivastigmine patches for ≥ 6 months and had previously received high doses of oral rivastigmine.

RESULTS

Mean caregiver age was 59.8±14.4 years and 70.9% were women. They spent 10.0±7.1hours per day providing care and 79.8% lived with the patient. Patch instructions were described as easy to follow by 97.1% of the caregivers and 92.1% of them rated patch application as easy or very easy. The most commonly cited disadvantage was adhesion problems (26.8%). Discontinuation of treatment was due to cutaneous reactions in most cases. Overall, 76.5% of the caregivers were satisfied or very satisfied with transdermal treatment and 77.4% considered that its interference with daily activities was minimal or null. The patch was preferred to oral treatment by 94.3% of caregivers. Clinical Global Impression of Change ratings improved according to 61.3% of the caregivers and 53% of the investigators. Few caregivers reported medication forgetfulness.

CONCLUSIONS

Most caregivers of patients with mild to moderate AD preferred the transdermal format of rivastigmine to the oral format. Caregivers also reported overall satisfaction, ease of use, and reduced impact on daily activities for transdermal rivastigmine format, in addition to patient improvement compared to their condition under the previous treatment.

Factors determining when to start levodopa/carbidopa/entacapone treatment in Spanish patients with Parkinson's disease

INTRODUCTION

Several therapeutic options are available for the symptomatic treatment of Parkinson's disease (PD).There is no reliable information about which factors are involved in the choice of treatment.

OBJECTIVE

To identify factors contributing to the decision to start treatment with levodopa/carbidopa/entacapone (LCE) in patients with PD.

PATIENTS AND METHODS

We completed a descriptive cross-sectional retrospective multicentre study of patients with idiopathic PD receiving LCE. Clinical data were collected with special attention to factors that could potentially determine when to initiate treatment with LCE in normal clinical practice.

RESULTS

We studied 1050 patients with a mean age of 71.3±8.7 years (58.2% men). Average time from onset of symptoms to diagnosis was 13.8±12.9 months, with a latency time of 74.5±53.6 months before starting LCE treatment. The most common initial symptoms were tremor (70.6%), reduced dexterity (43.2%) and slowness of movement (41.5%). At the start of LCE treatment, most patients were in Hoehn and Yahr stage 2 (57.5%), with an average rating of 73.4% on the Schwab & England scale. Eight hundred twenty two patients (78.3%) received treatment with other drugs before starting LCE (mean time between starting any PD treatment and starting LCE was 40.5±47.2 months). Clinical factors with a moderate, marked, or crucial effect on the decision to start LCE treatment were bradykinesia (84.7%), daytime rigidity (72.2%), general decline (72.2%), difficulty walking (66.4%), tremor (62.7%), nocturnal rigidity (56.1%), and postural instability (53%). Difficulty performing activities of daily living was the only psychosocial factor identified as having an influence on the decision (84.3%).

CONCLUSIONS

The decision to start patients with idiopathic PD on LCE treatment is mainly determined by motor deficits and disabilities associated with disease progression.

Congenital self-healing reticulohistiocytosis: report of a case and review of the literature

Congenital self-healing reticulohistiocytosis (CSHRH), a rare disorder initially seen at birth or in the newborn period, is characterized by spontaneously involuting skin lesions. We present the case of a 12-d-old female who was born with many red-brownish nodules scattered over her entire body, and which regressed spontaneously.

CONCLUSION

Although there are no clues to differentiate CSHRH from Letterer-Siwe disease, some signs and symptoms might enable us to reach an accurate diagnosis. A long-term follow-up to detect evidence of relapse or progression of the disease would be well advised.

Upper extremity deep vein thrombosis in a young patient double heterozygous for factor V Leiden and prothrombin G20210A mutation

We report on a 19-year-old girl with upper extremity deep vein thrombosis after catheter indwelling whose thrombophilic study disclosed the coexistence of factor V Leiden and the prothrombin G20210A mutation. The family study identified five other members who were also heterozygous for both mutations. This is the first case of upper extremity deep vein thrombosis with the co-inheritance of both genetic defects. It provides further evidence that thrombophilic defects mostly require additional triggering factors to induce a thrombotic event and suggests that in young patients with this venous thrombotic location, a thrombophilic search should be performed even when there are other acquired thrombotic risk factors.

Mitochondrial biogenesis in the liver during development and oncogenesis

The analysis of the expression of oxidative phosphorylation genes in the liver during development reveals the existence of two biological programs involved in the biogenesis of mitochondria. Differentiation is a short-term program of biogenesis that is controlled at post-transcriptional levels of gene expression and is responsible for the rapid changes in the bioenergetic phenotype of mitochondria. In contrast, proliferation is a long-term program controlled both at the transcriptional and post-transcriptional levels of gene expression and is responsible for the increase in mitochondrial mass in the hepatocyte. Recently, a specific subcellular structure involved in the localization and control of the translation of the mRNA encoding the beta-catalytic subunit of the H(+)-ATP synthase (beta-mRNA) has been identified. It is suggested that this structure plays a prominent role in the control of mitochondrial biogenesis at post-transcriptional levels. The fetal liver has many phenotypic manifestations in common with highly glycolytic tumor cells. In addition, both have a low mitochondrial content despite a paradoxical increase in the cellular representation of oxidative phosphorylation transcripts. Based on the paradigm provided by the fetal liver we hypothesize that the aberrant mitochondrial phenotype of fast-growing hepatomas represents a reversion to a fetal program of expression of oxidative phosphorylation genes by the activation, or increased expression, of an inhibitor of beta-mRNA translation.

Subcellular structure containing mRNA for beta subunit of mitochondrial H+-ATP synthase in rat hepatocytes is translationally active

We have recently reported that the nuclear-encoded mRNA for the beta subunit of mitochondrial H+-ATP synthase (beta-mRNA) is localized in rounded, electron-dense clusters in the cytoplasm of rat hepatocytes. Clusters of beta-mRNA are often found in close proximity to mitochondria. These findings suggested a role for these structures in controlling the cytoplasmic expression and sorting of the encoded mitochondrial precursor. Here we have addressed the question of whether the structures containing beta-mRNA are translationally active. For this purpose a combination of high-resolution in situ hybridization and immunocytochemical procedures was used. Three different co-localization criteria showed that beta-mRNA-containing structures always revealed positive immunoreactive signals for mitochondrial H+-ATP synthase (F1-ATPase), ribosomal and hsc70 proteins. Furthermore, clusters show evidence in situ of developmental changes in the translational efficiency of the beta-mRNA. These findings suggest that structures containing beta-mRNA are translationally active irrespective of their cytoplasmic location. The immunocytochemical quantification of the cytoplasmic presentation of hsc70 in the hepatocyte reveals that approx. 86% of the protein has a dispersed distribution pattern. However, the remaining hsc70 is presented in clusters of which only half reveal positive hybridization for beta-mRNA. The interaction of hsc70 with the beta-F1-ATPase precursor protein is documented by the co-localization of F1-ATPase immunoreactive material within cytoplasmic clusters of hsc70 and by the co-immunoprecipitation of hsc70 with the beta-subunit precursor from liver post-mitochondrial supernatants. Taken together, these results suggest a role for hsc70 in the translation/sorting pathway of the mammalian precursor of the beta-F1-ATPase protein.

mRNA encoding the beta-subunit of the mitochondrial F1-ATPase complex is a localized mRNA in rat hepatocytes

Subcellular mRNA localization has emerged as a mechanism for regulation of gene expression and protein-sorting pathways. Here we describe the different cytoplasmic presentation in rat hepatocytes of two nuclear mRNA species encoding subunits alpha and beta of the mitochondrial F1-ATPase complex. alpha-F1-ATPase mRNA is dispersed and scattered in the cytoplasm. In contrast, beta-F1-ATPase mRNA appears in rounded electron-dense clusters, often in close proximity to mitochondria. Hybridization experiments with beta2-microglobulin and beta-actin cDNA species reveal an expected subcellular distribution pattern of the mRNA species and a non-clustered appearance. Development does not alter the presentation of beta-F1-ATPase mRNA hybrids, although it affects the relative abundance of beta-F1-ATPase mRNA clusters in the cytoplasm of the hepatocyte. These findings illustrate in vivo the existence of two different sorting pathways for the nuclear-encoded mRNA species of mitochondrial proteins. High-resolution immunocytochemistry and immunoprecipitation experiments allowed the identification of the beta-subunit precursor in the cytoplasm of the hepatocyte, also suggesting a post-translational import pathway for this precursor protein. It is suggested that the localization of beta-F1-ATPase mRNA in a subcellular structure of the hepatocyte might have implications for the control of gene expression at post-transcriptional levels during mitochondrial biogenesis in mammals.

Changing patterns of transcriptional and post-transcriptional control of beta-F1-ATPase gene expression during mitochondrial biogenesis in liver

To elucidate the mechanisms that regulate the expression of nuclear genes during biogenesis of mammalian mitochondria, the expression pattern of the beta-subunit of the ATP synthase gene has been characterized in rat liver between day 20 in utero and 12 weeks postnatal. The parallelism existing between transcriptional activity of the gene and the amount of beta-F1-ATPase protein in liver indicates that proliferation of mitochondria is controlled at the transcriptional level. On the other hand, an increased stability (4-5-fold) of beta-F1-ATPase mRNA during early neonatal life as well as a rapid postnatal activation of translation rates affecting mitochondrial proteins appear to control mitochondrial differentiation. Immunoelectron microscopy of the F1-ATPase complex during liver development revealed that the rapid postnatal increase in the in vivo rate of F1-ATPase synthesis was mostly used for functional differentiation of pre-existing organelles (Valcarce, C., Navarrete, R. M., Encabo, P., Loeches, E., Satrústegui, J., and Cuezva, J. M. (1988) J. Biol Chem. 263, 7767-7775). The findings support that beta-F1-ATPase mRNA decay is developmentally regulated in liver, indicating that gene expression is also controlled at this level during physiological transitions that affect biogenesis of mitochondria.