Corrigendum to 'Single domain antibodies derived from ancient animals as broadly neutralizing agents for SARS-CoV-2 and other coronaviruses': Biomedical Engineering Advances 4 (2022) 100054.

[This corrects the article DOI: 10.1016/j.bea.2022.100054.].

Single domain antibodies derived from ancient animals as broadly neutralizing agents for SARS-CoV-2 and other coronaviruses.

With severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) as an emergent human virus since December 2019, the world population is susceptible to coronavirus disease 2019 (COVID-19). SARS-CoV-2 has higher transmissibility than the previous coronaviruses, associated by the ribonucleic acid (RNA) virus nature with high mutation rate, caused SARS-CoV-2 variants to arise while circulating worldwide. Neutralizing antibodies are identified as immediate and direct-acting therapeutic against COVID-19. Single-domain antibodies (sdAbs), as small biomolecules with non-complex structure and intrinsic stability, can acquire antigen-binding capabilities comparable to conventional antibodies, which serve as an attractive neutralizing solution. SARS-CoV-2 spike protein attaches to human angiotensin-converting enzyme 2 (ACE2) receptor on lung epithelial cells to initiate viral infection, serves as potential therapeutic target. sdAbs have shown broad neutralization towards SARS-CoV-2 with various mutations, effectively stop and prevent infection while efficiently block mutational escape. In addition, sdAbs can be developed into multivalent antibodies or inhaled biotherapeutics against COVID-19.

Congenital Partial Absence of Pericardium: A Mimic of Arrhythmogenic Right Ventricular Cardiomyopathy.

Congenital absence of pericardium is a rare condition with electrocardiogram, chest X-ray, and echocardiographic findings which may mimic those of other cardiac conditions. We present a case of a 19-year-old asymptomatic female with incidental cardiomegaly on chest X-ray and electrocardiographic and echocardiographic changes, which meet the revised task force criteria for definite arrhythmogenic right ventricular cardiomyopathy but subsequently confirmed to have congenital partial absence of pericardium on cardiac magnetic resonance imaging.

Dynamical Analysis of the Hindmarsh-Rose Neuron With Time Delays.

This brief is mainly concerned with a series of dynamical analyses of the Hindmarsh-Rose (HR) neuron with state-dependent time delays. The dynamical analyses focus on stability, Hopf bifurcation, as well as chaos and chaos control. Through the stability and bifurcation analysis, we determine that increasing the external current causes the excitable HR neuron to exhibit periodic or chaotic bursting/spiking behaviors and emit subcritical Hopf bifurcation. Furthermore, by choosing a fixed external current and varying the time delay, the stability of the HR neuron is affected. We analyze the chaotic behaviors of the HR neuron under a fixed external current through time series, bifurcation diagram, Lyapunov exponents, and Lyapunov dimension. We also analyze the synchronization of the chaotic time-delayed HR neuron through nonlinear control. Based on an appropriate Lyapunov-Krasovskii functional with triple integral terms, a nonlinear feedback control scheme is designed to achieve synchronization between the uncontrolled and controlled models. The proposed synchronization criteria are derived in terms of linear matrix inequalities to achieve the global asymptotical stability of the considered error model under the designed control scheme. Finally, numerical simulations pertaining to stability, Hopf bifurcation, periodic, chaotic, and synchronized models are provided to demonstrate the effectiveness of the derived theoretical results.

Unified selective sorting approach to analyse multi-electrode extracellular data.

Extracellular data analysis has become a quintessential method for understanding the neurophysiological responses to stimuli. This demands stringent techniques owing to the complicated nature of the recording environment. In this paper, we highlight the challenges in extracellular multi-electrode recording and data analysis as well as the limitations pertaining to some of the currently employed methodologies. To address some of the challenges, we present a unified algorithm in the form of selective sorting. Selective sorting is modelled around hypothesized generative model, which addresses the natural phenomena of spikes triggered by an intricate neuronal population. The algorithm incorporates Cepstrum of Bispectrum, ad hoc clustering algorithms, wavelet transforms, least square and correlation concepts which strategically tailors a sequence to characterize and form distinctive clusters. Additionally, we demonstrate the influence of noise modelled wavelets to sort overlapping spikes. The algorithm is evaluated using both raw and synthesized data sets with different levels of complexity and the performances are tabulated for comparison using widely accepted qualitative and quantitative indicators.

Impact of Caesarean section on subsequent fertility: a systematic review and meta-analysis.

STUDY QUESTION: Is there an association between a Caesarean section and subsequent fertility? SUMMARY ANSWER: Most studies report that fertility is reduced after Caesarean section compared with vaginal delivery. However, studies with a more robust design show smaller effects and it is uncertain whether the association is causal. WHAT IS KNOWN ALREADY: A previous systematic review published in 1996 summarizing six studies including 85 728 women suggested that Caesarean section reduces subsequent fertility. The included studies suffer from severe methodological limitations. STUDY DESIGN, SIZE, DURATION: Systematic review and meta-analysis of cohort studies comparing subsequent reproductive outcomes of women who had a Caesarean section with those who delivered vaginally. PARTICIPANTS/MATERIALS, SETTING, METHODS: Searches of Cochrane Library, Medline, Embase, CINAHL Plus and Maternity and Infant Care databases were conducted in December 2011 to identify randomized and non-randomized studies that compared the subsequent fertility outcomes after a Caesarean section and after a vaginal delivery. Eighteen cohort studies including 591 850 women matched the inclusion criteria. Risk of bias was assessed by the Newcastle-Ottawa scale (NOS). Data extraction was done independently by two reviewers. The meta-analysis was based on a random-effects model. Subgroup analyses were performed to assess whether the estimated effect was influenced by parity, risk adjustment, maternal choice, cohort period, and study quality and size. MAIN RESULTS AND THE ROLE OF CHANCE: The impact of Caesarean section on subsequent pregnancies could be analysed in 10 studies and on subsequent births in 16 studies. A meta-analysis suggests that patients who had undergone a Caesarean section had a 9% lower subsequent pregnancy rate [risk ratio (RR) 0.91, 95% confidence interval (CI) (0.87, 0.95)] and 11% lower birth rate [RR 0.89, 95% CI (0.87, 0.92)], compared with patients who had delivered vaginally. Studies that controlled for maternal age or specifically analysed primary elective Caesarean section for breech delivery, and those that were least prone to bias according to the NOS reported smaller effects. LIMITATIONS, REASONS FOR CAUTION: There is significant variation in the design and methods of included studies. Residual bias in the adjusted results is likely as no study was able to control for a number of important maternal characteristics, such as a history of infertility or maternal obesity. WIDER IMPLICATIONS OF THE FINDINGS: Further research is needed to reduce the impact of selection bias by indication through creating more comparable patient groups and applying risk adjustment.

Interleukin-18 system plays an important role in keloid pathogenesis via epithelial-mesenchymal interactions.

BACKGROUND: Keloid scarring is a dermal fibroproliferative disorder characterized by increased fibroblast proliferation and excessive production of collagen and extracellular matrix (ECM) components. To date, the role of cytokines in keloid pathogenesis has not been completely unravelled. Interleukin (IL)-18 is a pro-inflammatory cytokine that plays important roles in wound healing, fibrogenesis and carcinogenesis. OBJECTIVES: Our aim was to study the role of the IL-18 system in keloid pathogenesis. MATERIALS AND METHODS: Expression and localization of IL-18 and its receptor (IL-18R) were investigated in normal skin and keloid tissues using Western blot and immunohistochemistry. We further studied the expression of the IL-18 system in normal and keloid-derived cell lines in a coculture model. RESULTS: Results from Western blot and immunohistochemistry revealed that IL-18, IL-18Rα and IL-18Rß expression was elevated in keloid tissue compared with normal skin tissue. Studies on the expression of IL-18 and its antagonist, IL-18 binding protein (IL-18BP), using a coculture model demonstrated severe IL-18/IL-18BP imbalance in keloid keratinocyte/keloid fibroblast (KK/KF) cocultures with significant elevation of bioactive IL-18 whereas IL-18BP levels remained the same. This overproduction of bioactive IL-18 in keloid cocultures could be due to increased caspase-1 and decreased caspase-3 expression in keloid tissue, as well as decreased soluble IL-10 levels observed in keloid cocultures. The important inductive effects of IL-18 on KFs were further underscored by the observation that exposure of KF to IL-18 resulted in increased collagen and ECM component synthesis, and increased secretion of profibrotic cytokines such as IL-6 and IL-8. Finally, the addition of phosphatidylinositol 3-kinase (PI3K), mitogen activation protein kinase (MAPK), specificity protein 1 (Sp1) and mammalian target of rapamycin (mTOR) inhibitors inhibited IL-18 secretion in keloid cocultures. CONCLUSIONS: The present study has proven that the IL-18 system plays an important role in keloid pathogenesis via epithelial-mesenchymal interactions. It also suggests a therapeutic potential of PI3K, MAPK, Sp1 and mTOR inhibitors in the treatment of keloid scarring.

The role of stem cell factor and c-KIT in keloid pathogenesis: do tyrosine kinase inhibitors have a potential therapeutic role?

BACKGROUND: Keloids are fibroproliferative disorders characterized by increased deposition of extracellular matrix components. Stem cell factor (SCF) and its receptor c-KIT are expressed in a wide variety of cells and have also been demonstrated to be important modulators of the wound healing process. OBJECTIVES: To examine the role of the SCF/c-KIT system in keloid pathogenesis. METHODS: Immunohistochemical staining and Western blot analyses were used to examine localization and expression of SCF and c-KIT in keloid and normal skin tissue. This was followed by the detection of SCF and c-KIT expression in fibroblasts cultured in vitro and fibroblasts exposed to serum. To investigate the effect of epithelial-mesenchymal interactions, a two-chamber system was employed in which keratinocytes on membrane inserts were cocultured with the fibroblasts. SCF and c-KIT expression levels in all cell extracts and conditioned media were assayed by Western blotting. In another set of experiments, the effect of imatinib (Glivec(®), Gleevec(®); Novartis Pharma AG, Basel, Switzerland) on keloid fibroblasts was examined. RESULTS: SCF and c-KIT were upregulated in keloid scar tissue and in cultured fibroblasts stimulated with serum, highlighting their importance in the initial phase of wound healing. We further demonstrated that epithelial-mesenchymal interactions, mimicked by coculture of keratinocytes and fibroblasts in vitro, not only stimulated secretion of the soluble form of SCF in keloid cocultures but also brought about shedding of the extracellular domain of c-KIT perhaps by upregulation of tumour necrosis factor-α converting enzyme which was also upregulated in keloid scars in vivo and keloid cocultures in vitro. In addition keloid cocultures expressed increased levels of phosphorylated c-KIT highlighting an activation of the SCF/c-KIT system. Finally, we demonstrated that imatinib, a tyrosine kinase inhibitor, may be a possible therapeutic agent for keloids. CONCLUSION: These data indicate that the SCF/c-KIT system plays an important role in scar pathogenesis, and underscore the role of imatinib as a key therapeutic agent in keloid scars.

Hepatoma-derived growth factor and its role in keloid pathogenesis.

Hepatoma-derived growth factor (HDGF) is a novel mitogenic growth factor that has been implicated in many different carcinomas. Its role in keloid biology has not yet been investigated. The present study is aimed at examining the role of HDGF in keloid pathogenesis. Immunohistochemical staining and Western blot analyses were used to examine in vivo localization and expression of HDGF in keloid and normal skin tissue. This was followed by the detection of HDGF expression in fibroblasts cultured in vitro and fibroblasts exposed to serum. To investigate the effect of epithelial-mesenchymal interactions, a two-chamber system was employed in which keratinocytes on membrane inserts were co-cultured with the fibroblasts. HDGF expression levels in all cell extracts and conditioned media were assayed through Western blot analysis. In another set of experiments, the effect of exogenous recombinant HDGF on keloid fibroblasts (KF) and normal fibroblasts (NF) was examined. Cell proliferation was assessed by the MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay and by quantifying proliferating cell nuclear antigen (PCNA) expression. Downstream targets of HDGF were identified by detecting their expression through Western blot analysis. Our results indicate that there was an increase in HDGF expression in the dermis of keloid compared with normal skin tissue. The application of serum and epithelial-mesenchymal interactions did not seem to have any effect on intracellular HDGF expression levels. However, co-culturing keloid keratinocytes with KFs resulted in increased HDGF secretion when compared with monoculture or normal controls. Furthermore, treatment with exogenous recombinant HDGF was found to increase the proliferation of KFs, activate the extracellular signal-regulated kinase (ERK) pathway and up-regulate the secretion of vascular endothelial growth factor (VEGF).

Stat3 contributes to keloid pathogenesis via promoting collagen production, cell proliferation and migration.

Keloids, partially considered as benign tumors, represent the most extreme example of cutaneous scarring that uniquely afflicts humans as a pathological response to wound healing. It is characterized by excessive deposition of collagen and other extracellular matrix components by dermal fibroblasts. Upon cutaneous injury, cocktails of chemokines, cytokines and growth factors are secreted temporally and spatially to direct appropriate responses from neutrophils, macrophages, keratinocytes and fibroblasts to facilitate normal wound healing. Signal transducer and activator of transcription 3 (Stat3) is an oncogene and a latent transcription factor activated by various cytokines and growth factors. We investigated the possible role of Stat3 in keloid scar pathogenesis by examining skin tissue and cultured fibroblasts from keloid-scarred patients. We observed enhanced expression and phosphorylation of Stat3 in keloid scar tissue, and in cultured keloid fibroblasts (KFs) in vitro. Increased activation of Janus kinase (Jak)2, but not Jak1, was detected in KFs, and suppression of Jak2 by its inhibitor repressed Stat3 Y705 phosphorylation. Inhibition of Stat3 expression and phosphorylation by short interfering RNA or Cucurbitacin I resulted in the loss of collagen production, impaired proliferation and delayed cell migration in KFs. We show, for the first time, a role of Stat3 in keloid pathogenesis. Inhibitors of Stat3 may be useful therapeutic strategies for the prospective treatment of keloid scars.

Regulation of Stat3 activation by MEK kinase 1.

Stat3 is a latent transcription factor activated by various cytokines and growth factors. Phosphorylation on Tyr-705 is a prerequisite for dimer formation, nuclear translocation, binding to its cognate DNA sequences, and regulation of the target gene transcription. Ser-727 phosphorylation of Stat3 plays an additional role in the regulation of transcription. MEK kinase 1 (MEKK1) is a mitogen-activated protein kinase (MAPK) kinase kinase (MAPKKK) that activates the c-Jun NH(2)-terminal kinase signaling pathway. Here we report that MEKK1 is involved in the regulation of Stat3 activation by growth factors. Kinase-inactive MEKK1 inhibits Stat3 phosphorylation on tyrosine and serine, and its transcriptional activity stimulated by epidermal growth factor and platelet-derived growth factor in different cell types. In contrast, active MEKK1 induces Stat3 tyrosine and serine phosphorylation leading to a functionally active Stat3 capable of binding DNA and enhancing transcription. Ser-727 is phosphorylated by MEKK1 in vitro, whereas Tyr-705 phosphorylation induced by MEKK1 involves Src and Janus kinases in vivo. These data demonstrate for the first time a novel role of MEKK1 to modulate tyrosine kinases that results in the activation of specific members of STAT family.

Use of artificial neural networks to predict drug dissolution profiles and evaluation of network performance using similarity factor.

PURPOSE: To use artificial neural networks for predicting dissolution profiles of matrix-controlled release theophylline pellet preparation, and to evaluate the network performance by comparing the predicted dissolution profiles with those obtained from physical experiments using similarity factor. METHODS: The Multi-Layered Perceptron (MLP) neural network was used to predict the dissolution profiles of theophylline pellets containing different ratios of microcrystalline cellulose (MCC) and glyceryl monostearate (GMS). The concepts of leave-one-out as well as a time-point by time-point estimation basis were used to predict the rate of drug release for each matrix ratio. All the data were used for training, except for one set which was selected to compare with the predicted output. The closeness between the predicted and the reference dissolution profiles was investigated using similarity factor (f2). RESULTS: The f2 values were all above 60, indicating that the predicted dissolution profiles were closely similar to the dissolution profiles obtained from physical experiments. CONCLUSION: The MLP network could be used as a model for predicting the dissolution profiles of matrix-controlled release theophylline pellet preparation in product development.

Serine phosphorylation and negative regulation of Stat3 by JNK.

STATs are activated by various cytokines and growth factors via tyrosine phosphorylation, which leads to sequential dimer formation, nuclear translocation, binding to specific DNA sequences, and regulation of gene expression. Recently, serine phosphorylation of Stat3 on Ser-727 by ERK has been identified in response to epidermal growth factor (EGF). Here, we report that Ser-727 phosphorylation of Stat3 can also be induced by JNK and activated either by stress or by its upstream kinase and that various stress treatments induce serine phosphorylation of Stat3 in the absence of tyrosine phosphorylation. Inhibitors of ERK and p38 did not inhibit UV-induced Stat3 serine phosphorylation, suggesting that neither of them is involved. We further demonstrate that JNK1, activated by its upstream kinase MKK7, negatively regulated the tyrosine phosphorylation and DNA binding and transcriptional activities of Stat3 stimulated by EGF. Correspondingly, pretreatment of cells with UV reduced the EGF-stimulated tyrosine phosphorylation and phosphotyrosine-dependent activities of Stat3. The inhibitory effect was not observed for Stat1. Our results suggest that Stat3 is a target of JNK that may regulate Stat3 activity via both Ser-727 phosphorylation-dependent and -independent mechanisms.

Stress-induced immediate-early gene, egr-1, involves activation of p38/JNK1.

The Ras/Raf/MAP kinase (ERK) pathway is a major signaling pathway induced by growth factors in mammalian cells. Two other types of mammalian MAP kinases, JNK (SAPK) and p38 (RK, CSBP), are induced by environmental stress. Although the immediate-early gene, egr-1, is induced by growth factors, cytokines, differentiation signals and DNA damaging agents, less is known about its induction by environmental stress and the mechanism involved. Here we report that in NIH3T3 cells, egr-1 is induced by various stress treatments such as heat shock, sodium arsenite, ultraviolet (U.V.) radiation, and anisomycin. p38 and JNK1, but not ERK2, were activated by these stress treatments. Induction of egr-1 by anisomycin is inhibited by a specific inhibitor of p38, SB 203580. We also show that p38 and JNK1 activated by their upstream kinases induce egr-1 promoter activity through activation of the ternary complex factor, Elk-1. The stress treatments also lead to an increase in Egr-1 protein phosphorylation and its DNA binding activity. Together, our data suggest that induction of egr-1 gene by growth factors and stress are mediated through different subgroups of MAP kinases which may also differentially affect egr-1 function on its target genes.

Repression of Stat3 activity by activation of mitogen-activated protein kinase (MAPK).

STAT proteins are activated by phosphorylation at specific tyrosine residue at the carboxy-terminus which is required for dimer-formation, nuclear translocation, DNA binding and transcriptional activity in cells treated with cytokines and growth factors. Recent studies have indicated that STATs are also phosphorylated by MAPK, or extracellular signal-regulated kinase (ERK) on serine. We investigated the role of ERK on the regulation of STAT activity. Here, we report that ERK2 activated by its upstream kinase, MEK1, represses Stat3 transcriptional activity induced by Src or Jak-2. To unravel the mechanism of repression, we further showed that Stat3 DNA binding activity and its tyrosine phosphorylation are also inhibited under the same conditions. ERK2 phosphorylates Stat3 on three serine-containing peptides and decreases its tyrosine phosphorylation induced by EGF treatment. We also detected an association of ERK2 and Stat3 in vivo which is modulated positively by activation of ERK2, but negatively by Jak2. We propose that MAP kinase cascade may negatively regulate Stat3 activities by decreasing its tyrosine phosphorylation and also possibly by association.

Application of autonomous neural network systems to medical pattern classification tasks.

This paper presents a study of the application of autonomously learning multiple neural network systems to medical pattern classification tasks. In our earlier work, a hybrid neural network architecture has been developed for on-line learning and probability estimation tasks. The network has been shown to be capable of asymptotically achieving the Bayes optimal classification rates, on-line, in a number of benchmark classification experiments. In the context of pattern classification, however, the concept of multiple classifier systems has been proposed to improve the performance of a single classifier. Thus, three decision combination algorithms have been implemented to produce a multiple neural network classifier system. Here the applicability of the system is assessed using patient records in two medical domains. The first task is the prognosis of patients admitted to coronary care units; whereas the second is the prediction of survival in trauma patients. The results are compared with those from logistic regression models, and implications of the system as a useful clinical diagnostic tool are discussed.