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Dietary fiber is considered an essential constituent of a healthy child’s diet. Diets of healthy children with adequate dietary fiber intake are characterized by a higher diet quality, a higher nutrient density, and a higher intake of vitamins and minerals in comparison to the diets of children with poor dietary fiber intake. Nevertheless, a substantial proportion of children do not meet the recommended dietary fiber intake. This is especially true in those children with kidney diseases, as traditional dietary recommendations in kidney diseases have predominantly focused on the quantities of energy and protein, and often restricting potassium and phosphate, while overlooking the quality and diversity of the diet. Emerging evidence suggests that dietary fiber and, by extension, a plant-based diet with its typically higher dietary fiber content are just as important for children with kidney diseases as for healthy children. Dietary fiber confers several health benefits such as prevention of constipation and fewer gastrointestinal symptoms, reduced inflammatory state, and decreased production of gut-derived uremic toxins. Recent studies have challenged the notion that a high dietary fiber intake confers an increased risk of hyperkalemia or nutritional deficits in children with kidney diseases. There is an urgent need of new studies and revised guidelines that address the dietary fiber intake in children with kidney diseases.

After identifying a captive herd of white-tailed deer in central Texas with >94% seroprevalence with SARS-CoV-2 neutralizing antibodies in September 2021, we worked retrospectively through archived serum samples of 21 deer and detected seroconversion of all animals between December 2020 and January 2021. We then collected prospective samples to conclude that the duration of persistence of neutralizing antibodies is at least 13 months for 19 (90.5%) of the animals, with two animals converting to seronegative after six and eight months. Antibody titres generally waned over this time frame, but three deer had a temporary 4- to 8-fold increases in plaque reduction neutralization test titres over a month after seroconversion; anamnestic response cannot be ruled out.

Background As countries move towards or achieve measles elimination status, serosurveillance is an important public health tool. However, a major challenge of serosurveillance is finding a feasible, accurate, cost-effective, and high throughput assay to measure measles antibody concentrations and estimate susceptibility in a population. We conducted a systematic review to assess, characterize, and – to the extent possible – quantify the performance of measles IgG enzyme-linked assays (EIAs) compared to the gold standard, plaque reduction neutralization tests (PRNT). Methods We followed the PRISMA statement for a systematic literature search and methods for conducting and reporting systematic reviews and meta-analyses recommended by the Cochrane Screening and Diagnostic Tests Methods Group. We identified studies through PubMed and Embase electronic databases and included serologic studies detecting measles virus IgG antibodies among participants of any age from the same source population that reported an index (any EIA or multiple bead-based assays, MBA) and reference test (PRNT) using sera, whole blood, or plasma. Measures of diagnostic accuracy with 95% confidence intervals (CI) were abstracted for each study result, where reported. Results We identified 550 unique publications and identified 36 eligible studies for analysis. We classified studies as high, medium, or low quality; results from high quality studies are reported. Because most high quality studies used the Siemens Enzygnost EIA kit, we generate individual and pooled diagnostic accuracy estimates for this assay separately. Median sensitivity of the Enzygnost EIA was 92.1% [IQR = 82.3, 95.7]; median specificity was 96.9 [93.0, 100.0]. Pooled sensitivity and specificity from studies using the Enzygnost kit were 91.6 (95%CI: 80.7,96.6) and 96.0 (95%CI: 90.9,98.3), respectively. The sensitivity of all other EIA kits across high quality studies ranged from 0% to 98.9% with median (IQR) = 90.6 [86.6, 95.2]; specificity ranged from 58.8% to 100.0% with median (IQR) = 100.0 [88.7, 100.0]. Conclusions Evidence on the diagnostic accuracy of currently available measles IgG EIAs is variable, insufficient, and may not be fit for purpose for serosurveillance goals. Additional studies evaluating the diagnostic accuracy of measles EIAs, including MBAs, should be conducted among diverse populations and settings (e.g., vaccination status, elimination/endemic status, age groups).

Zika virus has emerged in the Americas, where dengue virus is endemic. Among the 4 serotypes of dengue virus, antibody-dependent enhancement is thought to enhance viral replication and disease severity. Reports suggest that anti–dengue virus antibody may enhance Zika virus replication. We investigated whether Zika virus antibodies enhance dengue virus replication, by exposing C57B1/6 mice to Zika virus. Polyclonal serum was verified for strong Zika virus-neutralizing, dengue virus-subneutralizing capacity. Then we determined the enhancement capabilities of Zika virus–immune serum for dengue virus in vitro. We showed that Zika virus antibodies have the ability to enhance dengue virus infections, which is important, because in many Zika virus-affected areas, dengue virus is expected to remain endemic.

Dyskalemias are often seen in children with chronic kidney disease (CKD). While hyperkalemia is common, with an increasing prevalence as glomerular filtration rate declines, hypokalemia may also occur, particularly in children with renal tubular disorders and those on intensive dialysis regimens. Dietary assessment and adjustment of potassium intake is critically important in children with CKD as hyperkalemia can be life-threatening. Manipulation of dietary potassium can be challenging as it may affect the intake of other nutrients and reduce palatability. The Pediatric Renal Nutrition Taskforce (PRNT), an international team of pediatric renal dietitians and pediatric nephrologists, has developed clinical practice recommendations (CPRs) for the dietary management of potassium in children with CKD stages 2–5 and on dialysis (CKD2–5D). We describe the assessment of dietary potassium intake, requirements for potassium in healthy children, and the dietary management of hypo- and hyperkalemia in children with CKD2–5D. Common potassium containing foods are described and approaches to adjusting potassium intake that can be incorporated into everyday practice discussed. Given the poor quality of evidence available, a Delphi survey was conducted to seek consensus from international experts. Statements with a low grade or those that are opinion-based must be carefully considered and adapted to individual patient needs, based on the clinical judgment of the treating physician and dietitian. These CPRs will be regularly audited and updated by the PRNT.

Yellow fever (YF) is a mosquito-borne viral haemorrhagic disease that remains endemic in parts of South America and Africa. Although there is a safe and effective vaccine that has been available for over 75 years, YF remains a public health problem in areas with endemic as well as sporadic transmission. Immune responses elicited by natural infection with yellow fever virus and vaccination are marked by production of neutralizing antibodies. Serological cross-reactivity exhibited by flaviviruses poses challenges to the diagnostic tests for detection of YF-specific antibodies. The most specific plaque reduction neutralization test (PRNT) is considered the “gold standard” test for detecting and measuring the neutralizing antibodies. This study was undertaken to develop and validate in-house PRNT50 test for measurement of YF specific neutralizing antibodies. We validated PRNT50 test using different parameters including specificity, linearity, precision, accuracy and robustness. The YF PRNT50 assay was shown to be specific, robust, precise and accurate. Thus, we have proven suitability of this assay for evaluation of neutralizing antibodies in response to YF vaccination in case of natural infections.

Background & objectives: The global pandemic caused by SARS-CoV-2 virus has challenged public health system worldwide due to the unavailability of approved preventive and therapeutic options. Identification of neutralizing antibodies (NAb) and understanding their role is important. However, the data on kinetics of NAb response among COVID-19 patients are unclear. To understand the NAb response in COVID-19 patients, we compared the findings of microneutralization test (MNT) and plaque reduction neutralization test (PRNT) for the SARS-CoV-2. Further, the kinetics of NAb response among COVID-19 patients was assessed. Methods: A total of 343 blood samples (89 positive, 58 negative for SARS-CoV-2 and 17 cross-reactive and 179 serum from healthy individuals) were collected and tested by MNT and PRNT. SARS-CoV-2 virus was prepared by propagating the virus in Vero CCL-81 cells. The intra-class correlation was calculated to assess the correlation between MNT and PRNT. The neutralizing endpoint as the reduction in the number of plaque count by 90 per cent (PRNT90) was also calculated. Results: The analysis of MNT and PRNT quantitative results indicated that the intra-class correlation was 0.520. Of the 89 confirmed COVID-19 patients, 64 (71.9%) showed NAb response. Interpretation & conclusions: The results of MNT and PRNT were specific with no cross-reactivity. In the early stages of infection, the NAb response was observed with variable antibody kinetics. The neutralization assays can be used for titration of NAb in recovered/vaccinated or infected COVID-19 patients.

•We successfully displayed six ZIKV B-cell epitopes on the surface of phage VLPs.•Two of these epitopes were displayed on MS2 and PP7 VLPs by genetic insertion.•The remaining 4 epitopes were displayed on Qβ VLPs by chemical conjugation.•VLPs displaying single ZIKV B-cell epitopes were immunogenic but minimally reduced ZIKV in vitro.•Sera from mice with mixed VLPs displaying multiple ZIKV epitopes neutralized ZIKV in vitro. Zika virus (ZIKV) is a mosquito-borne flavivirus that has re-emerged and is associated with many debilitating clinical manifestations. Research is currently being conducted to develop a prophylactic vaccine against the virus; however, there has not been any licensed ZIKV vaccine. Recent studies have identified potential B-cell epitopes (amino acids 241–259, 294–315, 317–327, 346–361, 377–388 and 421–437) on the envelope protein of ZIKV, which could be explored to develop peptide vaccines against ZIKV infection. Nevertheless, the immunogenicity of these epitopes has never been assessed. Here, we displayed these epitopes on highly immunogenic bacteriophage virus-like particles (VLPs; MS2, PP7 and Qβ) platforms and assessed their immunogenicity in mice. Mice immunized with a mixture of VLPs displaying ZIKV envelope B-cell epitopes elicited anti-ZIKV antibodies. Although, immunized mice were not protected against a high challenge dose of ZIKV, sera – albeit at low titers – from immunized mice neutralized (in vitro) a low dose of ZIKV. Taken together, these results show that these epitopes are B-cell epitopes and they are immunogenic when displayed on a Qβ VLP platform. Furthermore, the results also show that immunization with VLPs displaying a single B-cell epitope minimally reduces ZIKV infection whereas immunization with a mixture of VLPs displaying a combination of the B-cell epitopes neutralizes ZIKV infection. Thus, immunization with a mixture of VLPs displaying multiple ZIKV B-cell epitopes is a good strategy to enhance ZIKV neutralization.

Serological assays are useful in investigating the development of humoral immunity against SARS-CoV-2 in the context of epidemiological studies focusing on the spread of protective immunity. The plaque reduction neutralization test (PRNT) is the gold standard method to assess the titer of protective antibodies in serum samples. However, to provide a result, the PRNT requires several days, skilled operators, and biosafety level 3 laboratories. Therefore, alternative methods are being assessed to establish a relationship between their outcomes and PRNT results. In this work, four different immunoassays (Roche Elecsys® Anti SARS-CoV-2 S, Snibe MAGLUMI® SARS-CoV-2 S-RBD IgG, Snibe MAGLUMI® 2019-nCoV IgG, and EUROIMMUN® SARS-CoV-2 NeutraLISA assays, respectively) have been performed on individuals healed after SARS-CoV-2 infection. The correlation between each assay and the reference method has been explored through linear regression modeling, as well as through the calculation of Pearson’s and Spearman’s coefficients. Furthermore, the ability of serological tests to discriminate samples with high titers of neutralizing antibodies (>160) has been assessed by ROC curve analyses, Cohen’s Kappa coefficient, and positive predictive agreement. The EUROIMMUN® NeutraLISA assay displayed the best correlation with PRNT results (Pearson and Spearman coefficients equal to 0.660 and 0.784, respectively), as well as the ROC curve with the highest accuracy, sensitivity, and specificity (0.857, 0.889, and 0.829, respectively).

The plaque reduction neutralization test (PRNT) is a preferred method for the detection of functional, SARS-CoV-2 specific neutralizing antibodies from serum samples. Alternatively, surrogate enzyme-linked immunosorbent assays (ELISAs) using ACE2 as the target structure for the detection of neutralization-competent antibodies have been developed. They are capable of high throughput, have a short turnaround time, and can be performed under standard laboratory safety conditions. However, there are very limited data on their clinical performance and how they compare to the PRNT. We evaluated three surrogate immunoassays (GenScript SARS-CoV-2 Surrogate Virus Neutralization Test Kit (GenScript Biotech, Piscataway Township, NJ, USA), the TECO® SARS-CoV-2 Neutralization Antibody Assay (TECOmedical AG, Sissach, Switzerland), and the Leinco COVID-19 ImmunoRank™ Neutralization MICRO-ELISA (Leinco Technologies, Fenton, MO, USA)) and one automated quantitative SARS-CoV-2 Spike protein-based IgG antibody assay (Abbott GmbH, Wiesbaden, Germany) by testing 78 clinical samples, including several follow-up samples of six BNT162b2 (BioNTech/Pfizer, Mainz, Germany/New York, NY, USA) vaccinated individuals. Using the PRNT as a reference method, the overall sensitivity of the examined assays ranged from 93.8 to 100% and specificity ranged from 73.9 to 91.3%. Weighted kappa demonstrated a substantial to almost perfect agreement. The findings of our study allow these assays to be considered when a PRNT is not available. However, the latter still should be the preferred choice. For optimal clinical performance, the cut-off value of the TECO assay should be individually adapted.