Novel antibody competition binding assay identifies distinct serological profiles associated with protection

Introduction

Pre-erythrocytic malaria vaccines hold the promise of inducing sterile protection thereby preventing the morbidity and mortality associated with Plasmodium infection. The main surface antigen of P. falciparum sporozoites, i.e., the circumsporozoite protein (CSP), has been extensively explored as a target of such vaccines with significant success in recent years. Systematic adjuvant selection, refinements of the immunization regimen, and physical properties of the antigen may all contribute to the potential of increasing the efficacy of CSP-based vaccines. Protection appears to be dependent in large part on CSP antibodies. However due to a knowledge gap related to the exact correlates of immunity, there is a critical need to improve our ability to down select candidates preclinically before entering clinical trials including with controlled human malaria infections (CHMI).

Methods

We developed a novel multiplex competition assay based on well-characterized monoclonal antibodies (mAbs) that target crucial epitopes across the CSP molecule. This new tool assesses both, quality and epitope-specific concentrations of vaccine-induced antibodies by measuring their equivalency with a panel of well-characterized, CSP-epitope-specific mAbs.

Results

Applying this method to RTS,S-immune sera from a CHMI trial demonstrated a quantitative epitope-specificity profile of antibody responses that can differentiate between protected vs. nonprotected individuals. Aligning vaccine efficacy with quantitation of the epitope fine specificity results of this equivalency assay reveals the importance of epitope specificity.

Discussion

The newly developed serological equivalence assay will inform future vaccine design and possibly even adjuvant selection. This methodology can be adapted to other antigens and disease models, when a panel of relevant mAbs exists, and could offer a unique tool for comparing and down-selecting vaccine formulations.

An Assessment of the Public's Perceptions of Radiation Exposure and Risk Associated With Dental Radiographs: A Cross-Sectional Study

BACKGROUND

Ionizing radiation exposure is an ever-present part of the dental diagnostic process. A public concern often exists due to the misunderstanding of the stochastic effects of dental X-rays. This information can be difficult to explain to the patient since many patients are apprehensive about the subject matter.

OBJECTIVE

This article aims to assess the public's knowledge of radiation exposure and estimate the general concern or apprehension about these diagnostic imaging modalities in an effort to understand and therefore ensure patient reassurance during treatment.

METHOD

A questionnaire was conducted asking adults between the ages of 18 to 74 in Jeddah, Saudi Arabia questions pertaining to radiation risk.

RESULTS

 There were 105 respondents; 21.9% showed concerns toward dental imaging, while 20% were skeptical. approximately 74% of respondents believed there was a limit to the amount of radiation exposure a patient could receive for diagnostic purposes, while only eight percent correctly identified that there was no set limit. Only 21.9% knew that a breastfeeding mother could have dental X-rays if need be; 33.3% understood that ionizing radiation from an intra-oral dental X-ray caused less exposure than natural background radiation from a return flight from Jeddah to Dammam.  Conclusions: Patients are not aware of ionizing radiation exposure equivalencies between different imaging modalities. A more effective approach to convey exposure risk would be relating the radiation doses to natural background radiation as comparators.

Why equianalgesic tables are only part of the answer to equianalgesia

Opioids are an important tool in the management of acute and chronic (cancer and non-cancer) pain. Pain and palliative care practitioners are frequently called upon to switch a patient from one opioid regimen to a different regimen either to gain better pain control, to minimize opioid-related adverse effects, to overcome opioid tolerance, or due to a change in patient status. To this end, equianalgesic tables have been published to guide practitioners in making these calculations. Despite being built on the best data available, equianalgesic tables do not tell the whole story, requiring the practitioner to thoroughly consider the patient's situation, and unknown variables. A five-step process is presented in this article that espouse a safe and effective way to switch from one opioid regimen to another. Directions for the future include better refinement of the data that informs the equianalgesic table, and perhaps inclusion of opioid utility data.

Evaluation of chemiluminescent immunoassay quantitative detection for pro-gastrin-releasing peptide (ProGRP) in serum and plasma

OBJECTIVE

To evaluate a newly developed Hybiome ProGRP chemiluminescent assay.

METHODS

Analytical sensitivity, precision, recovery, and equivalency of serum and plasma, serum stability, and complement interference of the Hybiome ProGRP assay were evaluated. Serum specimens from 318 individuals including 38 small cell lung cancer (SCLC), 65 non-small cell lung cancer (NSCLC), 53 benign lung diseases, and 162 healthy controls were assessed using the Hybiome ProGRP assay and Roche Elecsys ProGRP assay, and the results were compared.

RESULTS

The Hybiome ProGRP assay showed good analytical sensitivity, precision, and accuracy, and it showed equivalence between serum and plasma and serum stability. The methodological comparison results showed good correlation between the Hybiome and Roche assays (slope, 0.9889; intercept, 1.28). Both the Hybiome and Roche assays showed good ability to distinguish between SCLC and NSCLC. Based on 95% specificity in the NSCLC cohort, a clinical differentiation cut-off for separating SCLC from NSCLC patients was 114 pg/mL for the Hybiome assay and 117 pg/mL for the Roche assay; the AUC was 0.9166 and the sensitivity was 71.05% for Hybiome and 0.9045 and 76.32% for Roche, respectively.

CONCLUSION

The Hybiome ProGRP chemiluminescent assay shows good analytical performance and good correlation with the Roche Elecsys ProGRP assay.

Equivalency and practice effects of alternative versions of the Edinburgh Cognitive and Behavioral ALS Screen (ECAS)

To examine the equivalency of ECAS versions A, B, and C in an Irish cohort, and to examine potential practice effects, 236 healthy controls were recruited through the Irish ALS control database. One hundred and seventy-six (176) controls completed ECAS version A, B, or C. Separately, 60 controls completed all three versions (A-B-C), consecutively, four months apart. TOST analysis found that ECAS A was equivalent to ECAS B and C. ECAS B and C were not statistically equivalent, however the difference between them was minimal. Participants showed improvement in ECAS performance over time, indicative of practice effects. Significant improvement was observed from time 1 to 2, but not from time 2 to 3. We propose Irish specific reliable change index (RCI) scores that take into consideration practice effects and measurement error. These thresholds will help quantify clinically meaningful cognitive decline in ALS patients, leading to improved quality of care.

Psychometric Equivalence of the Computerized and Original Halstead Category Test Using a Matched Archival Sample

Objective: Investigate the equivalence of several psychometric measures between the traditional Halstead Category Test (HCT-Original Version [OV]) and the computer-based Halstead Category Test (HCT-Computerized Version [CV]). Method: Data were from a diagnostically heterogeneous, archival sample of 211 adults administered either the HCT by computer (n = 105) or cabinet (n = 106) as part of a neuropsychological evaluation. Groups were matched on gender, race, education, Full Scale Intelligence Quotient, and Global Neuropsychological Deficit Score. Confirmatory factor analysis was used to examine structural equivalence. Score, variability, and reliability equivalency were also examined. Differential item and test functioning under a Rasch model were examined. Results: An identified factor structure from research of the HCT-OV fit the HCT-CV scores adequately: χ²(4) = 8.83, p = .07; root mean square error of approximation = 0.10 [0.00, 0.20]; standardized root mean residual = 0.03; comparative fit index = 0.99. Total scores and variability of subtest scores were not consistently equivalent between the two administration groups. Reliability estimates were, however, similar and adequate for clinical practice: 0.96 for HCT-OV and 0.97 for HCT-CV. About 17% of items showed possible differential item functioning, though just three of these items were statistically significant. Differential test functioning revealed expected total score differences of <1% between versions. Conclusion: The results of this study suggest that the HCT-CV functions similar to the HCT-OV with there being negligible differences in expected total scores between these versions. The HCT-CV demonstrated good psychometric properties, particularly reliability and construct validity consistent with previous literature. Further study is needed to generalize these findings and to further examine the equivalency of validity evidence between versions.

Categorizing and Establishing CD4 Service Equivalency: Testing of Residual, Archived External Quality Assessment Scheme Sample Panels Enables Accelerated Virtual Peer Laboratory Review

BACKGROUND

Testing of collated, curated residual archived external quality assessment (EQA) trial material, with pre-established true (consensus) values collated into 25-sample panels enables virtual peer review of a laboratory's proficiency. In this study, we introduce how archived EQAS samples/panels can establish equivalency of CD4 reporting across multiple laboratories in a national program.

METHODS

Curated unused trial material from archived EQAS CD4 trials were collated into 25-sample panels comprising three sets of five-sample replicates and at least three duplicate samples. Panel-samples were tested using predicate methods of participating laboratories and proficiency determined by calculating a Standard Deviation Index (SDI) for each panel-sample reported according to retrospective consensus pooled trial outcomes. All data were plotted using MS Excel and Graphpad-Prism with SDI limits between -2 and +2 SDI to define acceptable performance. Percentage similarity analysis determined agreement. Bead-count-rate data was used to determine pipetting error.

RESULTS

Tight clustering of SDI outcomes predicted acceptable laboratory proficiency with acceptable accuracy and precision as evidenced by mean SDI < 0.5 and SD of SDI < 0.5. Random pipetting error was identified with aberrant BCR. Systematic under-reading of results was noted in one lab with excellent precision but mean SDI > 1.6. Additional training requirements were evident where a respective laboratory's SD of SDI exceeded 0.7.

CONCLUSIONS

Archival panel testing undertaken across a network of CD4 laboratories using the same CD4 method to simultaneously test the same panel prior to national implementation highlighted proficient laboratories and was useful for identifying sites with service deficiencies and immediate additional training needs. © 2019 International Clinical Cytometry Society.

Dose Equivalents for Antipsychotic Drugs: The DDD Method

BACKGROUND

Dose equivalents of antipsychotics are an important but difficult to define concept, because all methods have weaknesses and strongholds.

METHODS

We calculated dose equivalents based on defined daily doses (DDDs) presented by the World Health Organisation's Collaborative Center for Drug Statistics Methodology. Doses equivalent to 1mg olanzapine, 1mg risperidone, 1mg haloperidol, and 100mg chlorpromazine were presented and compared with the results of 3 other methods to define dose equivalence (the "minimum effective dose method," the "classical mean dose method," and an international consensus statement).

RESULTS

We presented dose equivalents for 57 first-generation and second-generation antipsychotic drugs, available as oral, parenteral, or depot formulations. Overall, the identified equivalent doses were comparable with those of the other methods, but there were also outliers.

CONCLUSIONS

The major strength of this method to define dose response is that DDDs are available for most drugs, including old antipsychotics, that they are based on a variety of sources, and that DDDs are an internationally accepted measure. The major limitations are that the information used to estimate DDDS is likely to differ between the drugs. Moreover, this information is not publicly available, so that it cannot be reviewed. The WHO stresses that DDDs are mainly a standardized measure of drug consumption, and their use as a measure of dose equivalence can therefore be misleading. We, therefore, recommend that if alternative, more "scientific" dose equivalence methods are available for a drug they should be preferred to DDDs. Moreover, our summary can be a useful resource for pharmacovigilance studies.

Equivalence and practice effect of alternate forms for Malay version of Auditory Verbal Learning Test (MAVLT)

This study aims to develop two alternate forms for Malay version of Auditory Verbal Learning Test (MAVLT) and to determine their equivalency and practice effect. Ninety healthy volunteers were subjected to the following neuropsychological tests at baseline, and at one month interval according to their assigned group; group 1 (MAVLT - MAVLT), group 2 (MAVLT – Alternate Form 1 - Alternate Form 1), and group 3 (MAVLT - Alternate Form 2 - Alternate Form 2). There were no significant difference in the mean score of all the trials at baseline among the three groups, and most of the mean score of trials between MAVLT and Alternate Form 1, and between MAVLT and Alternate Form 2. There was significant improvement in the mean score of each trial when the same form was used repeatedly at the interval of one month. However, there was no significant improvement in the mean score of each trial when the Alternate Form 2 was used during repeated neuropsychological testing. The MAVLT is a reliable instrument for repeated neuropsychological testing as long as alternate forms are used. The Alternate Form 2 showed better equivalency to MAVLT and less practice effects.

Accuracy of three activity monitors in patients with chronic obstructive pulmonary disease: a comparison with video recordings

Low physical activity and sedentary behaviour characterise the lives of patients with chronic obstructive pulmonary disease (COPD). Using activity monitors, assessment of both aspects are possible, but many outcomes are not well validated. The aim of this study was to assess the accuracy and equivalency of three activity monitors regarding steps, body position and their ability to differentiate between periods of physical activity and inactivity. Fifteen patients with COPD (8 females; median (interquartile range, IQR) age, 64 (59-69) years; forced expiratory volume in 1 second, 37 (28-48)% predicted; 6-minute walk distance, 444 (410-519) m) were enrolled. The DynaPort ADL-monitor, the DynaPort MiniMod monitor and the SenseWear Armband Pro 3 monitor were assessed. Subjects performed a structured protocol alternating physical activity and inactivity while simultaneously wearing all three monitors and being video recorded. The mean difference (limits of agreement) in step count from monitors compared to manual step count was -69 (-443 to 305) for the ADL-monitor, -19 (-141 to 103) for the MiniMod and -479 (-855 to -103) for the SenseWear Armband. Compared to the video, the sitting time was 97 (94-100)% when measured by the ADL-monitor and 121 (110-139)% by the MiniMod. Standing time was 114 (107-122)% when measured by the ADL-monitor and 68 (47-106)% by the MiniMod. Activity monitors are not equivalent in their abilities to detect steps or body positions. The choice of monitor should be based on the particular outcome of interest.

Dose equivalents for second-generation antipsychotics: the minimum effective dose method

BACKGROUND

Clinicians need to know the right antipsychotic dose for optimized treatment, and the concept of dose equivalence is important for many clinical and scientific purposes.

METHODS

We refined a method presented in 2003, which was based on the minimum effective doses found in fixed-dose studies. We operationalized the selection process, updated the original findings, and expanded them by systematically searching more recent literature and by including 13 second-generation antipsychotics. To qualify for the minimum effective dose, a dose had to be significantly more efficacious than placebo in the primary outcome of at least one randomized, double-blind, fixed-dose trial. In a sensitivity analysis, 2 positive trials were required. The minimum effective doses identified were subsequently used to derive olanzapine, risperidone, haloperidol, and chlorpromazine equivalents.

RESULTS

We reviewed 73 included studies. The minimum effective daily doses/olanzapine equivalents based on our primary approach were: aripiprazole 10 mg/1.33, asenapine 10 mg/1.33, clozapine 300 mg/40, haloperidol 4 mg/0.53, iloperidone 8 mg/1.07, lurasidone 40 mg/5.33, olanzapine 7.5 mg/1, paliperidone 3 mg/0.4, quetiapine 150 mg/20, risperidone 2 mg/0.27, sertindole 12 mg/1.60, and ziprasidone 40 mg/5.33. For amisulpride and zotepine, reliable estimates could not be derived.

CONCLUSIONS

This method for determining antipsychotic dose equivalence entails an operationalized and evidence-based approach that can be applied to the various antipsychotic drugs. As a limitation, the results are not applicable to specific populations such as first-episode or refractory patients. We recommend that alternative methods also be updated in order to minimize further differences between the methods and risk of subsequent bias.