Complexities of Long-Term Care With Gastro-Jejunal (GJ) Feeding Tubes and Enteral Migration During COVID-19 Pandemic Times: A Case Report.

Gastro-jejunostomy tubes, or percutaneous endoscopic gastrostomy tubes with jejunal extension (PEG-J), hold a significant role in the long-term nutritional management of patients with poor oral intake. This can be for a variety of reasons; ranging from metabolic conditions, including diabetes mellitus, inherited or congenital conditions like Ehler Danlos syndrome, or patients with neurological disorders, such as stroke, advanced Parkinson's disease or multiple sclerosis. Although they are very helpful for the overall nutritional needs of such patients, they are associated with complications, including the dislodging of jejunal tubes. The need to promptly recognise, investigate and manage this, in a timely manner, is vital, particularly during the COVID-19 pandemic times, as such patients may be associated with multiple comorbidities.

Linking Inflammation, Aberrant Glutamate-Dopamine Interaction, and Post-synaptic Changes: Translational Relevance for Schizophrenia and Antipsychotic Treatment: a Systematic Review.

Evidence from clinical, preclinical, and post-mortem studies supports the inflammatory/immune hypothesis of schizophrenia pathogenesis. Less evident is the link between the inflammatory background and two well-recognized functional and structural findings of schizophrenia pathophysiology: the dopamine-glutamate aberrant interaction and the alteration of dendritic spines architecture, both believed to be the "quantal" elements of cortical-subcortical dysfunctional network. In this systematic review, we tried to capture the major findings linking inflammation, aberrant glutamate-dopamine interaction, and post-synaptic changes under a direct and inverse translational perspective, a paramount picture that at present is lacking. The inflammatory effects on dopaminergic function appear to be bidirectional: the inflammation influences dopamine release, and dopamine acts as a regulator of discrete inflammatory processes involved in schizophrenia such as dysregulated interleukin and kynurenine pathways. Furthermore, the link between inflammation and glutamate is strongly supported by clinical studies aimed at exploring overactive microglia in schizophrenia patients and maternal immune activation models, indicating impaired glutamate regulation and reduced N-methyl-D-aspartate receptor (NMDAR) function. In addition, an inflammatory/immune-induced alteration of post-synaptic density scaffold proteins, crucial for downstream NMDAR signaling and synaptic efficacy, has been demonstrated. According to these findings, a significant increase in plasma inflammatory markers has been found in schizophrenia patients compared to healthy controls, associated with reduced cortical integrity and functional connectivity, relevant to the cognitive deficit of schizophrenia. Finally, the link between altered inflammatory/immune responses raises relevant questions regarding potential new therapeutic strategies specifically for those forms of schizophrenia that are resistant to canonical antipsychotics or unresponsive to clozapine.

Rational and Translational Implications of D-Amino Acids for Treatment-Resistant Schizophrenia: From Neurobiology to the Clinics.

Schizophrenia has been conceptualized as a neurodevelopmental disorder with synaptic alterations and aberrant cortical-subcortical connections. Antipsychotics are the mainstay of schizophrenia treatment and nearly all share the common feature of dopamine D2 receptor occupancy, whereas glutamatergic abnormalities are not targeted by the presently available therapies. D-amino acids, acting as N-methyl-D-aspartate receptor (NMDAR) modulators, have emerged in the last few years as a potential augmentation strategy in those cases of schizophrenia that do not respond well to antipsychotics, a condition defined as treatment-resistant schizophrenia (TRS), affecting almost 30-40% of patients, and characterized by serious cognitive deficits and functional impairment. In the present systematic review, we address with a direct and reverse translational perspective the efficacy of D-amino acids, including D-serine, D-aspartate, and D-alanine, in poor responders. The impact of these molecules on the synaptic architecture is also considered in the light of dendritic spine changes reported in schizophrenia and antipsychotics' effect on postsynaptic density proteins. Moreover, we describe compounds targeting D-amino acid oxidase and D-aspartate oxidase enzymes. Finally, other drugs acting at NMDAR and proxy of D-amino acids function, such as D-cycloserine, sarcosine, and glycine, are considered in the light of the clinical burden of TRS, together with other emerging molecules.

Palliative Long-Term Abdominal Drains Versus Large Volume Paracentesis in Refractory Ascites Due to Cirrhosis (REDUCe Study): Qualitative Outcomes.

CONTEXT: Palliative care remains suboptimal in end-stage liver disease (ESLD). OBJECTIVES: We report qualitative outcomes from the REDUCe study. We aimed to explore and contrast experiences/perceptions/care pathways of patients with refractory ascites due to ESLD randomized to either palliative long-term abdominal drains (LTADs) (allow home drainage) vs. large volume paracentesis (LVP) (hospital drainage). METHODS: Concurrent embedded qualitative study in a 12-week feasibility randomized controlled trial. Telephone interviews were conducted, data being recorded, transcribed verbatim, and analyzed using applied thematic analysis, considered in terms of a pathway approach toward accessing health care. Quantitative outcomes were collected (integrated palliative outcome scale, short-form liver disease quality of life, EQ-5D-5 L, Zarit Burden Interview-12). RESULTS: Fourteen patients (six allocated LTAD and eight LVP) and eight nurses participated in the qualitative study. The patient journey in the LVP group could be hindered by challenges along the entire care pathway, from recognizing the need for drainage to a lengthy wait in hospital for drainage and/or to be discharged. These issues also impacted upon caregivers. In contrast, LTADs appeared to transform this care pathway at all levels across the patient's journey by removing the need for hospital drainage. Additional benefits included personalized care, improved symptom control of ascites, being at home, and regular support from community nurses. Nurses also viewed the LTAD favorably, though expressed the need for additional support should this become standard of care. CONCLUSION: Patients and nurses expressed acceptability of palliative LTAD in ESLD and preference for this approach in enabling care at home. Proceeding to a definitive trial is feasible. TRIAL REGISTRATION: ISRCTN30697116, date assigned: 07/10/2015.

Structural and functional characterization of C0021158, a high-affinity monoclonal antibody that inhibits Arginase 2 function via a novel non-competitive mechanism of action.

Arginase 2 (ARG2) is a binuclear manganese metalloenzyme that catalyzes the hydrolysis of L-arginine. The dysregulated expression of ARG2 within specific tumor microenvironments generates an immunosuppressive niche that effectively renders the tumor 'invisible' to the host's immune system. Increased ARG2 expression leads to a concomitant depletion of local L-arginine levels, which in turn leads to suppression of anti-tumor T-cell-mediated immune responses. Here we describe the isolation and characterization of a high affinity antibody (C0021158) that inhibits ARG2 enzymatic function completely, effectively restoring T-cell proliferation in vitro. Enzyme kinetic studies confirmed that C0021158 exhibits a noncompetitive mechanism of action, inhibiting ARG2 independently of L-arginine concentrations. To elucidate C0021158's inhibitory mechanism at a structural level, the co-crystal structure of the Fab in complex with trimeric ARG2 was solved. C0021158's epitope was consequently mapped to an area some distance from the enzyme's substrate binding cleft, indicating an allosteric mechanism was being employed. Following C0021158 binding, distinct regions of ARG2 undergo major conformational changes. Notably, the backbone structure of a surface-exposed loop is completely rearranged, leading to the formation of a new short helix structure at the Fab-ARG2 interface. Moreover, this large-scale structural remodeling at ARG2's epitope translates into more subtle changes within the enzyme's active site. An arginine residue at position 39 is reoriented inwards, sterically impeding the binding of L-arginine. Arg39 is also predicted to alter the pKA of a key catalytic histidine residue at position 160, further attenuating ARG2's enzymatic function. In silico molecular docking simulations predict that L-arginine is unable to bind effectively when antibody is bound, a prediction supported by isothermal calorimetry experiments using an L-arginine mimetic. Specifically, targeting ARG2 in the tumor microenvironment through the application of C0021158, potentially in combination with standard chemotherapy regimens or alternate immunotherapies, represents a potential new strategy to target immune cold tumors.

Extensive sequence and structural evolution of Arginase 2 inhibitory antibodies enabled by an unbiased approach to affinity maturation.

Affinity maturation is a powerful technique in antibody engineering for the in vitro evolution of antigen binding interactions. Key to the success of this process is the expansion of sequence and combinatorial diversity to increase the structural repertoire from which superior binding variants may be selected. However, conventional strategies are often restrictive and only focus on small regions of the antibody at a time. In this study, we used a method that combined antibody chain shuffling and a staggered-extension process to produce unbiased libraries, which recombined beneficial mutations from all six complementarity-determining regions (CDRs) in the affinity maturation of an inhibitory antibody to Arginase 2 (ARG2). We made use of the vast display capacity of ribosome display to accommodate the sequence space required for the diverse library builds. Further diversity was introduced through pool maturation to optimize seven leads of interest simultaneously. This resulted in antibodies with substantial improvements in binding properties and inhibition potency. The extensive sequence changes resulting from this approach were translated into striking structural changes for parent and affinity-matured antibodies bound to ARG2, with a large reorientation of the binding paratope facilitating increases in contact surface and shape complementarity to the antigen. The considerable gains in therapeutic properties seen from extensive sequence and structural evolution of the parent ARG2 inhibitory antibody clearly illustrate the advantages of the unbiased approach developed, which was key to the identification of high-affinity antibodies with the desired inhibitory potency and specificity.

Randomised clinical trial: palliative long-term abdominal drains vs large-volume paracentesis in refractory ascites due to cirrhosis.

BACKGROUND: Palliative care remains suboptimal in end-stage liver disease. AIM: To inform a definitive study, we assessed palliative long-term abdominal drains in end-stage liver disease to determine recruitment, attrition, safety/potential effectiveness, questionnaires/interview uptake/completion and make a preliminary cost comparison. METHODS: A 12-week feasibility nonblinded randomised controlled trial comparing large-volume paracentesis vs long-term abdominal drains in refractory ascites due to end-stage liver disease with fortnightly home visits for clinical/questionnaire-based assessments. Study success criteria were attrition not >50%, <10% long-term abdominal drain removal due to complications, the long-term abdominal drain group to spend <50% ascites-related study time in hospital vs large-volume paracentesis group and 80% questionnaire/interview uptake/completion. RESULTS: Of 59 eligible patients, 36 (61%) were randomised, 17 to long-term abdominal drain and 19 to large-volume paracentesis. Following randomisation, median number (IQR) of hospital ascitic drains (long-term abdominal drain group vs large-volume paracentesis group) were 0 (0-1) vs 4 (3-7); week 12 serum albumin (g/L) and serum creatinine (µmol/L) were 29 (26.5-32.5) vs 30 (25-35) and 104.5 (81-115.5) vs 127 (63-158) respectively. Total attrition was 42% (long-term abdominal drain group 47%, large-volume paracentesis group 37%). Median (IQR) fortnightly community/hospital/social care ascites-related costs and percentage study time in hospital were lower in the long-term abdominal drain group, £329 (253-580) vs £843 (603-1060) and 0% (0-0.74) vs 2.75% (2.35-3.84) respectively. Self-limiting cellulitis/leakage occurred in 41% (7/17) in the long-term abdominal drain group vs 11% (2/19) in the large-volume paracentesis group; peritonitis incidence was 6% (1/17) vs 11% (2/19) respectively. Questionnaires/interview uptake/completion were ≥80%; interviews indicated that long-term abdominal drains could transform the care pathway. CONCLUSIONS: The REDUCe study demonstrates feasibility with preliminary evidence of long-term abdominal drain acceptability/effectiveness/safety and reduction in health resource utilisation. TRIAL REGISTRATION: ISRCTN30697116, date assigned: 07/10/2015.

Key role of the 5-HT1A receptor addressing protein Yif1B in serotonin neurotransmission and SSRI treatment.

Background: Altered function of serotonin receptor 1A (5-HT1AR) has been consistently implicated in anxiety, major depressive disorder and resistance to antidepressants. Mechanisms by which the function of 5-HT1AR (expressed as an autoreceptor in serotonergic raphe neurons and as a heteroreceptor in serotonin [5-HT] projection areas) is altered include regulation of its expression, but 5-HT1AR trafficking may also be involved. Methods: We investigated the consequences of the lack of Yif1B (the 5-HT1AR trafficking protein) on 5-HT neurotransmission in mice, and whether Yif1B expression might be affected under conditions known to alter 5-HT neurotransmission, such as anxious or depressive states or following treatment with fluoxetine (a selective serotonin reuptake inhibitor) in humans, monkeys and mice. Results: Compared with wild-type mice, Yif1B-knockout mice showed a significant decrease in the forebrain density of 5-HT projection fibres and a hypofunctionality of 5-HT1A autoreceptors expressed on raphe 5-HT neurons. In addition, social interaction was less in Yif1B-knockout mice, which did not respond to the antidepressant-like effect of acute fluoxetine injection. In wild-type mice, social defeat was associated with downregulated Yif1B mRNA in the prefrontal cortex, and chronic fluoxetine treatment increased Yif1B expression. The expression of Yif1B was also downregulated in the postmortem prefrontal cortex of people with major depressive disorder and upregulated after chronic treatment with a selective serotonin reuptake inhibitor in monkeys. Limitations: We found sex differences in Yif1B expression in humans and monkeys, but not in mice under the tested conditions. Conclusion: These data support the concept that Yif1B plays a critical role in 5-HT1AR functioning and brain 5-HT homeostasis. The opposite changes in its expression observed in anxious or depressive states and after therapeutic fluoxetine treatment suggest that Yif1B might be involved in vulnerability to anxiety and depression, and fluoxetine efficacy.

Strategies for interfacing with the trigeminal nerves in rodents for bioelectric medicine.

BACKGROUND: Bioelectric medicine seeks to modulate neural activity via targeted electrical stimulation to treat disease. Recent clinical evidence supports trigeminal nerve stimulation as a bioelectric treatment for several neurological disorders; however, the mechanisms of trigeminal nerve stimulation and potential side effects remain largely unknown. The goal of this study is to optimize the methodology and reproducibility of neural interface implantation for mechanistic studies in rodents. NEW METHOD(S): This article describes a single incision surgical approach to the infraorbital nerve of rats and mice and the supraorbital nerve in rats for trigeminal nerve stimulation studies. This article also presents the use of cortical evoked potentials and electromyography as methods for demonstrating effective engagement between the implanted electrode and target nerve. COMPARISON WITH EXISTING METHOD(S): A number of surgical approaches to the infraorbital nerve in rats exist, many of which are technically difficult. A simple, standardized approach to infraorbital nerve in rats and mice, as well as the supraorbital nerve of rats is integral to reproducibility of future trigeminal nerve stimulation studies. CONCLUSION: The infraorbital nerve of rats and mice can be easily accessed from a single dorsal incision on the bridge of the nose that avoids major anatomical structures such as the facial nerve. The supraorbital nerve is also accessible in rats from a single dorsal incision, but not mice due to size. Successful interfacing and engagement of the infra- and supraorbital nerves using the described methodology is demonstrated by recording of evoked cortical potentials and electromyography.

Computational Design of Epitope-Specific Functional Antibodies.

The ultimate goal of protein design is to introduce new biological activity. We propose a computational approach for designing functional antibodies by focusing on functional epitopes, integrating large-scale statistical analysis with multiple structural models. Machine learning is used to analyze these models and predict specific residue-residue contacts. We use this approach to design a functional antibody to counter the proinflammatory effect of the cytokine interleukin-17A (IL-17A). X-ray crystallography confirms that the designed antibody binds the targeted epitope and the interaction is mediated by the designed contacts. Cell-based assays confirm that the antibody is functional. Importantly, this approach does not rely on a high-quality 3D model of the designed complex or even a solved structure of the target. As demonstrated here, this approach can be used to design biologically active antibodies, removing some of the main hurdles in antibody design and in drug discovery.

Correction to: Palliative long-term abdominal drains versus repeated drainage in individuals with untreatable ascites due to advanced cirrhosis: study protocol for a feasibility randomised controlled trial.

Following publication of the original article [1], the authors reported that the figure legend for Figure 3 was absent. In addition, they have requested additional funding information to be added. In this Correction the initial and updated funding information are shown. The original publication of this article has been corrected.

Palliative long-term abdominal drains versus repeated drainage in individuals with untreatable ascites due to advanced cirrhosis: study protocol for a feasibility randomised controlled trial.

BACKGROUND: UK deaths due to chronic liver diseases such as cirrhosis have quadrupled over the last 40 years, making this condition now the third most common cause of premature death. Most patients with advanced cirrhosis (end-stage liver disease [ESLD]) develop ascites. This is often managed with diuretics, but if refractory, then the fluid is drained from the peritoneal cavity every 10-14 days by large volume paracentesis (LVP), a procedure requiring hospital admissions. As the life expectancy of patients with ESLD and refractory ascites (if ineligible for liver transplantation) is on average ≤ 6 months, frequent hospital visits are inappropriate from a palliative perspective. One alternative is long-term abdominal drains (LTADs), used successfully in patients whose ascites is due to malignancy. Although inserted in hospital, these drains allow ascites management outside of a hospital setting. LTADs have not been formally evaluated in patients with refractory ascites due to ESLD. METHODS/DESIGN: Due to uncertainty about appropriate outcome measures and whether patients with ESLD would wish or be able to participate in a study, a feasibility randomised controlled trial (RCT) was designed. Patients were consulted on trial design. We plan to recruit 48 patients with refractory ascites and randomise them (1:1) to either (1) LTAD or (2) current standard of care (LVP) for 12 weeks. Outcomes of interest include acceptability of the LTAD to patients, carers and healthcare professionals as well as recruitment and retention rates. The Integrated Palliative care Outcome Scale, the Short Form Liver Disease Quality of Life questionnaire, the EuroQol 5 dimensions instrument and carer-reported (Zarit Burden Interview) outcomes will also be assessed. Preliminary data on cost-effectiveness will be collected, and patients and healthcare professionals will be interviewed about their experience of the trial with a view to identifying barriers to recruitment. DISCUSSION: LTADs could potentially improve end-of-life care in patients with refractory ascites due to ESLD by improving symptom control, reducing hospital visits and enabling some self-management. Our trial is designed to see if such patients can be recruited, as well as to inform the design of a subsequent definitive trial. TRIAL REGISTRATION: ISRCTN, ISRCTN30697116 . Registered on 7 October 2015.

Length of axons expressing the serotonin transporter in orbitofrontal cortex is lower with age in depression.

Studies of major depressive disorder (MDD) in postmortem brain tissue report enhanced binding to inhibitory serotonin-1A autoreceptors in midbrain dorsal raphe and reductions in length of axons expressing the serotonin transporter (SERT) in dorsolateral prefrontal cortex. The length density of axons expressing SERT in the orbitofrontal cortex (OFC) was determined in 18 subjects with MDD and 17 age-matched control subjects. A monoclonal antibody was used to immunohistochemically label the SERT in fixed sections of OFC. The 3-dimensional length density of SERT-immunoreactive (ir) axons in layer VI of OFC was estimated. The age of subjects with MDD was negatively correlated with SERT axon length (r=-0.77, p<0.0005). The significant effect of age persisted when removing four depressed subjects with an antidepressant medication present at the time of death, or when removing nine depressed subjects that had a recent prescription for an antidepressant medication. Neither gender, tissue pH, postmortem interval, 5-HTTLPR genotype, time in fixative, nor death by suicide had a significant effect on axon length. The age-related decrease in SERT-ir axon length in MDD may reflect pathology of ascending axons passing through deep white matter hyperintensities. Greater length of axons expressing SERT in younger subjects with MDD may result in a significant deficit in serotonin availability in OFC.

The impact of automated hippocampal volumetry on diagnostic confidence in patients with suspected Alzheimer's disease: A European Alzheimer's Disease Consortium study.

INTRODUCTION: Hippocampal volume is a core biomarker of Alzheimer's disease (AD). However, its contribution over the standard diagnostic workup is unclear. METHODS: Three hundred fifty-six patients, under clinical evaluation for cognitive impairment, with suspected AD and Mini-Mental State Examination ≥20, were recruited across 17 European memory clinics. After the traditional diagnostic workup, diagnostic confidence of AD pathology (DCAD) was estimated by the physicians in charge. The latter were provided with the results of automated hippocampal volumetry in standardized format and DCAD was reassessed. RESULTS: An increment of one interquartile range in hippocampal volume was associated with a mean change of DCAD of -8.0% (95% credible interval: [-11.5, -5.0]). Automated hippocampal volumetry showed a statistically significant impact on DCAD beyond the contributions of neuropsychology, 18F-fluorodeoxyglucose positron emission tomography/single-photon emission computed tomography, and cerebrospinal fluid markers (-8.5, CrI: [-11.5, -5.6]; -14.1, CrI: [-19.3, -8.8]; -10.6, CrI: [-14.6, -6.1], respectively). DISCUSSION: There is a measurable effect of hippocampal volume on DCAD even when used on top of the traditional diagnostic workup.

Palliative long-term abdominal drains in refractory ascites due to end-stage liver disease: A case series.

BACKGROUND: Ascites, the commonest complication of cirrhosis, leads to frequent hospitalisations. Refractory ascites confers a median survival of 6 months without liver transplantation. In many, the management remains palliative (large-volume paracentesis). Despite calls for improvement, palliative and end-of-life care is not yet integrated into end-stage liver disease. Long-term abdominal drains are a palliative strategy in malignant ascites, but not end-stage liver disease. CASE PRESENTATION: A retrospective, single centre, case series review was performed of patients undergoing long-term abdominal drain placement for refractory ascites secondary to end-stage liver disease at a large teaching hospital between August 2011 and March 2013. Case management: Patients with end-stage liver disease and refractory ascites, where liver transplantation was not an option, were considered for long-term abdominal drains. Seven patients underwent successful long-term abdominal drain insertion after multi-professional assessment. Case outcome: Following long-term abdominal drain insertion, mean hospital attendances reduced to 1 (0-4) from 9 (4-21), with none for ascites management. Median survival after long-term abdominal drain insertion was 29 days (8-219). The complication rate was low and none life threatening. CONCLUSION: Palliative and end-of-life care needs in end-stage liver disease remain under-addressed. Our data suggest that long-term abdominal drains may be a safe and effective palliative intervention in end-stage liver disease. Prospective randomised controlled trials comparing large-volume paracentesis versus long-term abdominal drains in refractory ascites secondary to end-stage liver disease are warranted.

Defining Optimal Aerobic Exercise Parameters to Affect Complex Motor and Cognitive Outcomes after Stroke: A Systematic Review and Synthesis.

Although poststroke aerobic exercise (AE) increases markers of neuroplasticity and protects perilesional tissue, the degree to which it enhances complex motor or cognitive outcomes is unknown. Previous research suggests that timing and dosage of exercise may be important. We synthesized data from clinical and animal studies in order to determine optimal AE training parameters and recovery outcomes for future research. Using predefined criteria, we included clinical trials of stroke of any type or duration and animal studies employing any established models of stroke. Of the 5,259 titles returned, 52 articles met our criteria, measuring the effects of AE on balance, lower extremity coordination, upper limb motor skills, learning, processing speed, memory, and executive function. We found that early-initiated low-to-moderate intensity AE improved locomotor coordination in rodents. In clinical trials, AE improved balance and lower limb coordination irrespective of intervention modality or parameter. In contrast, fine upper limb recovery was relatively resistant to AE. In terms of cognitive outcomes, poststroke AE in animals improved memory and learning, except when training was too intense. However, in clinical trials, combined training protocols more consistently improved cognition. We noted a paucity of studies examining the benefits of AE on recovery beyond cessation of the intervention.

Monozygotic twins with NASH cirrhosis: cumulative effect of multiple single nucleotide polymorphisms?

 Multiple genetic and environmental factors interact to determine an individual's predisposition to non-alcoholic fatty liver disease and its phenotypic characteristics. Association studies have found a number of alleles associated with the development of non-alcoholic steatohepatitis. Our aim was to investigate whether multiple risk-associated alleles may be present in affected monozygotic twins, indicating underlying genetic predisposition to non-alcoholic steatohepatitis. We determined the genotype of 14 candidate gene polymorphisms (at 11 unlinked loci) in a set of monozygotic twins who presented with cirrhosis within 18 months of each other. Genotyping revealed multiple single nucleotide polymorphisms at 9 independent loci in genes PNPLA3, APOC3, GCKR, TRIB1, LYPLAL1, PPP1R3B, COL13A1, and EFCAB4B, previously implicated in contributing to non-alcoholic steatohepatitis pathogenesis. In conclusion, this case series illustrates the potential cumulative effect of multiple polymorphisms in the development and potential progression of a complex trait such as NASH cirrhosis.

A comparison of the ability of the human IgG1 allotypes G1m3 and G1m1,17 to stimulate T-cell responses from allotype matched and mismatched donors.

The immunogenicity of clinically administered antibodies has clinical implications for the patients receiving them, ranging from mild consequences, such as increased clearance of the drug from the circulation, to life-threatening effects. The emergence of methods to engineer variable regions resulting in the generation of humanised and fully human antibodies as therapeutics has reduced the potential for adverse immunogenicity. However, due to differences in sequence referred to as allotypic variation, antibody constant regions are not homogeneous within the human population, even within sub-classes of the same immunoglobulin isotype. For therapeutically administered antibodies, the potential exists for an immune response from the patient to the antibody if the allotype of patient and antibody do not match. Allotypic distribution in the human population varies within and across ethnic groups making the choice of allotype for a therapeutic antibody difficult. This study investigated the potential of human IgG1 allotypes to stimulate responses in human CD4(+) T cells from donors matched for homologous and heterologous IgG1 allotypes. Allotypic variants of the therapeutic monoclonal antibody trastuzumab were administered to genetically defined allotypic matched and mismatched donor T cells. No significant responses were observed in the mismatched T cells. To investigate the lack of T-cell responses in relation to mismatched allotypes, HLA-DR agretopes were identified via MHC associated peptide proteomics (MAPPs). As expected, many HLA-DR restricted peptides were presented. However, there were no peptides presented from the sequence regions containing the allotypic variations. Taken together, the results from the T-cell assay and MAPPs assay indicate that the allotypic differences in human IgG1 do not represent a significant risk for induction of immunogenicity.

The influence of propoxyphene withdrawal on opioid use in veterans.

PURPOSE: Our aim is to determine if propoxyphene withdrawal from the US market was associated with opioid continuation, continued chronic opioid use, and secondary propoxyphene-related adverse events (emergency department visits, opioid-related events, and acetaminophen toxicity). METHODS: Medical service use and pharmacy data from 19/11/08 to 19/11/11 were collected from the national Veterans Healthcare Administration healthcare databases. A quasi-experimental pre-post retrospective cohort design utilizing a historical comparison group provided the study framework. Logistic regression controlling for baseline covariates was used to estimate the effect of propoxyphene withdrawal. RESULTS: There were 24,328 subjects (policy affected n = 10,747; comparison n = 13,581) meeting inclusion criteria. In the policy-affected cohort, 10.6% of users ceased using opioids, and 26.6% stopped chronic opioid use compared with 3.8% and 13.5% in the historical comparison cohort, respectively. Those in the policy-affected cohort were 2.7 (95%CI: 2.5-2.8) and 3.2 (95%CI: 2.9-3.6) times more likely than those in the historical comparison cohort to discontinue chronic opioid and any opioid use, respectively. Changes in adverse events and Emergency Department (ED) visits were not different between policy-affected and historical comparison cohorts (p > 0.05). CONCLUSIONS: The withdrawal of propoxyphene-containing products resulted in rapid and virtually complete elimination in propoxyphene prescribing in the veterans population; however, nearly 90% of regular users of propoxyphene switched to an alternate opioid, and three quarters continued to use opioids chronically.

Structural and functional characterization of a specific antidote for ticagrelor.

Ticagrelor is a direct-acting reversibly binding P2Y12 antagonist and is widely used as an antiplatelet therapy for the prevention of cardiovascular events in acute coronary syndrome patients. However, antiplatelet therapy can be associated with an increased risk of bleeding. Here, we present data on the identification and the in vitro and in vivo pharmacology of an antigen-binding fragment (Fab) antidote for ticagrelor. The Fab has a 20 pM affinity for ticagrelor, which is 100 times stronger than ticagrelor's affinity for its target, P2Y12. Despite ticagrelor's structural similarities to adenosine, the Fab is highly specific and does not bind to adenosine, adenosine triphosphate, adenosine 5'-diphosphate, or structurally related drugs. The antidote concentration-dependently neutralized the free fraction of ticagrelor and reversed its antiplatelet activity both in vitro in human platelet-rich plasma and in vivo in mice. Lastly, the antidote proved effective in normalizing ticagrelor-dependent bleeding in a mouse model of acute surgery. This specific antidote for ticagrelor may prove valuable as an agent for patients who require emergency procedures.