Analysis of the initial lot of the CDC 2019-Novel Coronavirus (2019-nCoV) real-time RT-PCR diagnostic panel

At the start of the COVID-19 pandemic, the Centers for Disease Control and Prevention (CDC) designed, manufactured, and distributed the CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel for SARS-CoV-2 detection. The diagnostic panel targeted three viral nucleocapsid gene loci (N1, N2, and N3 primers and probes) to maximize sensitivity and to provide redundancy for virus detection if mutations occurred. After the first distribution of the diagnostic panel, state public health laboratories reported fluorescent signal in the absence of viral template (false-positive reactivity) for the N3 component and to a lesser extent for N1. This report describes the findings of an internal investigation conducted by the CDC to identify the cause(s) of the N1 and N3 false-positive reactivity. For N1, results demonstrate that contamination with a synthetic template, that occurred while the “bulk” manufactured materials were located in a research lab for quality assessment, was the cause of false reactivity in the first lot. Base pairing between the 3’ end of the N3 probe and the 3’ end of the N3 reverse primer led to amplification of duplex and larger molecules resulting in false reactivity in the N3 assay component. We conclude that flaws in both assay design and handling of the “bulk” material, caused the problems with the first lot of the 2019-nCoV Real-Time RT-PCR Diagnostic Panel. In addition, within this study, we found that the age of the examined diagnostic panel reagents increases the frequency of false positive results for N3. We discuss these findings in the context of improvements to quality control, quality assurance, and assay validation practices that have since been improved at the CDC.

Identification of Antibodies Against Neutrophil Surface Antigens in Two Iranian Patients with Autoimmune Neutropenia

Autoimmune neutropenia is a type of immune-mediated neutropenia, caused by antibody-induced neutrophil destruction. Here, we report two cases (a 3-year-old boy and a 9-year-old girl) with suspected autoimmune neutropenia. The presence of neutrophil antibodies in the sera of these two patients was investigated; using standard neutrophil antibody screening tests such as granulocyte immunofluorescence test (GIFT), granulocyte agglutination test (GAT), and lymphocyte immunofluorescence test (LIFT). A positive reactivity with two-panel cells was found in GIFT. No reactivities with panel cells were observed in GAT and LIFT. To the best of our knowledge, this is the first report for detecting the neutrophil reactive antibodies; using genotyped neutrophils in patients with autoimmune neutropenia in Iran. The final diagnosis of our patients was primary autoimmune neutropenia for the boy and autoimmune neutropenia associated with familial Mediterranean fever for the girl.

Development of a Kit for Rapid Immunochromatographic Detection of Sacbrood Virus Infecting Apis cerana (AcSBV) Based on Polyclonal and Monoclonal Antibodies Raised against Recombinant VP1 and VP2 Expressed in Escherichia coli

A Korean isolate of the sacbrood virus infecting Apis cerana (AcSBV-Kor) is the most destructive honeybee virus, causing serious economic damage losses in Korean apiculture. To address this, here, we attempted to develop an assay for the rapid detection of AcSBV-Kor based on immunochromatographic detection of constituent viral proteins. Genes encoding VP1 and VP2 proteins of AcSBV-Kor were cloned into an expression vector (pET-28a) and expressed in Escherichia coli BL21(DE3). During purification, recombinant VP1 (rVP1) and VP2 (rVP2) proteins were found in the insoluble fraction, with a molecular size of 26.7 and 24.9 kDa, respectively. BALB/c mice immunized with the purified rVP1 and rVP2 produced polyclonal antibodies (pAbs) such as pAb-rVP1 and pAb-rVP2. Western blot analysis showed that pAb-rVP1 strongly reacted with the homologous rVP1 but weakly reacted with heterologous rVP2. However, pAb-rVP2 strongly reacted not only with the homologous rVP2 but also with the heterologous rVP1. Spleen cells of the immunized mice fused with SP2/0-Ag14 myeloma cells produced monoclonal antibodies (mAbs) such as mAb-rVP1-1 and mAb-rVP2-13. Western blot analysis indicated that pAb-rVP1, pAb-rVP2, mAb-rVP1-1, and mAb-rVP2-13 reacted with AcSBV-infected honeybees and larvae as well as the corresponding recombinant proteins. These antibodies were then used in the development of a rapid immunochromatography (IC) strip assay kit with colloidal gold coupled to pAb-rVP1 and pAb-rVP2 at the conjugate pad and mAb-rVP1-1 and mAb-rVP2-13 at the test line. One antibody pair, pAb-rVP1/mAb-VP1-1, showed positive reactivity as low as 1.38 × 103 copies, while the other pair, pAb-rVP2/mAb-VP2-13, showed positive reactivity as low as 1.38 × 104 copies. Therefore, the antibody pair pAb-rVP1/mAb-VP1-1 was selected as a final candidate for validation. To validate the detection of AcSBV, the IC strip tests were conducted with 50 positive and 50 negative samples and compared with real-time PCR tests. The results confirm that the developed IC assay is a sufficiently sensitive and specific detection method for user-friendly and rapid detection of AcSBV.

Age-related enhancements in positive emotionality across the lifespan: structural equation modelling of brain and behaviour

Ageing is associated with a bias in attention and memories towards positive and away from negative emotional content. In addition, emotion regulation appears to improve with age, despite concomitant widespread cognitive decline coupled with gray matter volume loss in cortical and subcortical regions thought to sub-serve emotion regulation. Here, we address this emotion-aging paradox using the behavioural data of an emotion regulation task from a population derived sample (CamCAN) and utilise Structural Equation Modelling together with multivariate analysis of structural MRI images of the same sample to investigate brain-behaviour relationships. In a series of measurement models, we show the relationship between age and emotionality is best explained by a four-factor model, compared to single and hierarchical factor models. These four latent factors are interpreted as Basal Negative Affect, Positive Reactivity, Negative Reactivity and Positive Regulation (upregulating positive emotion to negative content). Increasing age uniquely contributes to increased Basal Negative Affect, Positive Reactivity and Positive Regulation, but not Negative Reactivity. Furthermore, we show gray-matter volumes, namely in the bilateral frontal operculum, medial frontal gyrus, bilateral hippocampal complex, bilateral middle temporal gyri and bilateral angular gyrus, are distinctly related to these four latent factors. Finally, we show that a subset of these brain-behaviour relationships remain significant when accounting for age and demographic data. Our results support the notion of an age-related increase in basal emotionality together with a positivity bias and are interpreted in the context of the Socioemotional Selectivity Theory of improved emotion regulation in older age.

A Model of Atherosclerosis using Nicotine with Balloon Overdilation in a Porcine

Pigs are one of the important experimental animals for cardiovascular research. Few porcine coronary atherosclerosis models have been developed; however, the induction of which requires longer than 6 months. We developed a porcine coronary artery atherosclerosis model using nicotine injection with a balloon overdilation. A coronary balloon was placed in the porcine coronary artery and was over dilated to induce a mechanical injury. Nicotine was administrated via intramuscular injection every day and changes in the coronary artery were observed after 4 weeks. Coronary angiography revealed nicotine injection with a balloon overdilation groups showed narrowing of the coronary artery at the injury site. Combination of balloon and nicotine significantly increased the intimal hyperplasia on optical coherence tomography analysis. Proliferated tunica media was noted in the nicotine injection with balloon overdilation groups. Quantitative analysis showed increased smooth muscle actin alpha (SMA), cluster of differentiation 68 (CD68), and Krüppel-like factor 4 (KLF4) in the nicotine injection with balloon overdilation groups. The immunohistochemistry results showed CD68-positive cells displayed SMA- and KLF4-positive reactivity in the border zone of intimal hyperplasia. Our results show that nicotine injection with balloon overdilation can induce an atherosclerosis lesion within one month, which mimics the human atherosclerosis.

Affective neural signatures do not distinguish women with emotion dysregulation from healthy controls: A mega-analysis across three task-based fMRI studies

Pathophysiological models are urgently needed for personalized treatments of mental disorders. However, most potential neural markers for psychopathology are limited by low interpretability, prohibiting reverse inference from brain measures to clinical symptoms and traits. Neural signatures—i.e. multivariate brain-patterns trained to be both sensitive and specific to a construct of interest—might alleviate this problem, but are rarely applied to mental disorders. We tested whether previously developed neural signatures for negative affect and discrete emotions distinguish between healthy individuals and those with mental disorders characterized by emotion dysregulation, i.e. Borderline Personality Disorder (BPD) and complex Post-traumatic Stress Disorder (cPTSD). In three different fMRI studies, a total sample of 192 women (49 BPD, 62 cPTSD, 81 healthy controls) were shown pictures of scenes with negative or neutral content. Based on pathophysiological models, we hypothesized higher negative and lower positive reactivity of neural emotion signatures in participants with emotion dysregulation. The expression of neural signatures differed strongly between neutral and negative pictures (average Cohen’s d = 1.17). Nevertheless, a mega-analysis on individual participant data showed no differences in the reactivity of neural signatures between participants with and without emotion dysregulation. Confidence intervals ruled out even small effect sizes in the hypothesized direction and were further supported by Bayes factors. Overall, these results support the validity of neural signatures for emotional states during fMRI tasks, but raise important questions concerning their link to individual differences in emotion dysregulation.

Low-grade fibromyxoid sarcoma incidentally discovered as an asymptomatic mediastinal mass: a case report and review of the literature

Background Low-grade fibromyxoid sarcoma (LGFMS) is a rare tumor characterized by bland histological features and aggressive clinical course. The most common anatomic locations of occurrence are the lower extremities, thorax, inguinal area, and upper limbs. Primary mediastinal sarcomas are even rarer. To the best of our knowledge, only seven cases of primary mediastinal LGFMS have been reported in the literature. Here, we report a case of primary mediastinal LGFMS. Case presentation A 26-year-old Pakistani man presented with fever and vomiting for the past 2 months. On a routine chest x-ray, a mediastinal mass was incidentally found. Computed tomography (CT) scan showed a large circumscribed lobulated soft tissue density mass lesion in an anterior mediastinum. Grossly, the resected mass measured 17.0 × 12.0 × 11.0 cm. The cut surface was gray white with a whorled-like appearance and foci of calcification and cystic changes. Histologically, a spindle cell lesion was seen with alternating myxoid and hyalinized areas. The shaped cells were arranged in bundles. Immunohistochemical staining showed positive reactivity patterns with MUC4 and focally for epithelial membrane antigen (EMA). The diagnosis was confirmed as LGFMS. The patient is free of symptoms and recurrence 22 months after the surgery. Conclusion In conclusion, we report a rare case of primary mediastinal LGFMS in a young male patient that was discovered incidentally. Our patient is on regular follow-up to look for evidence of recurrence as these tumors are prone to recurrences.

Evaluation of influence of IL-6 C-572G gene polymorphism and clinical factors on positive platelet antibody test

Background: Interleukin-6 (IL-6) promotes antibody production. The objective of this study was to investigate whether IL-6 C-572G single nucleotide polymorphisms (SNP) and clinical factors are associated with positive platelet antibody test. Materials and methods: Thirty platelet recipients with platelet antibodies (responders) and 20 platelet recipients without platelet antibodies (non-responders) were randomly selected. The -572 C>G (rs 1800796) SNPs in the promoter region of IL-6 gene were genotyped by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) method. Solid phase red cell adherence assay (SPRCA) was used for platelet antibody detection. Results: Age, sex, percentage patients with benign diseases, and percentage of patients with homozygotes for the C allele at position -572 of the IL-6 gene were similar between responders and non-responders. Although the amounts of platelets pheresis transfused to patients with hematologic diseases were higher than those of non-hematologic diseases (47.2 ± 54.2 vs. 17.4 ± 13.8 units, p = 0.019), detection rate of platelet antibodies was lower in patients with hematologic diseases than that in patients with non-hematologic diseases (42.3% vs. 79.2%, p = 0.01). Conclusion: There was no association between IL-6 C-572G gene polymorphism and positive reactivity in solid phase platelet antibody detection method in platelet recipients.

BURNUP CALCULATIONS OF THE JSI TRIGA REACTOR FUEL AND COMPARISON WITH MEASUREMENTS

Fuel burnup of the JSI TRIGA was calculated by simulating complete operational history consisting of 240 different core configurations from 1966 to 2020. At the moment we are unable to perform burnup measurements, e.g. gamma spectroscopy on burned fuel elements, hence we used weekly measured excess reactivity as a reference point of different core configurations to verify the calculated core reactivity. Changes in reactivity due to burnup were assumed to be linear and this assumption was verified for burnup intervals smaller than 3 MWd/kg(HM). The comparison was performed on 46 different core configurations with different type of fuel elements. The Serpent-2 calculations decently predict the rate of reactivity change on different cases, as 52 % of calculations are withing 1σ and 86.9 % within 2σ of the measurements for total number of 46 cases. Additional analysis was performed by comparing unit cell calculations of different fuel types. Four different types of TRIGA fuel were used to analyse burnup changes in LEU and HEU fuel, where positive reactivity feedback on burnup was observed for HEU fuel due to burnable absorbers. Serpent-2 and WIMSD-5B were compared on unit-cell basis where good agreement within 200 pcm of reactivity change for large burnup was observed. In addition neutron spectrum changes due to burnup were investigated using unit-cell calculations where 4 % increase of the thermal peak and 1 % decrease of fast peak of the spectrum was observed for typical fuel burnups of 20 MWd/kg(HM), which approximately represents JSI TRIGA burnup at this moment.