A multiplex DNA probe-based method for simultaneous identification of adulteration in meat samples

Meat adulteration and admixing are prevalent malpractices observed in processed and raw meat samples, where the consumption of adulterated meat has been associated with food allergies, financial losses, and consumer distrust. Meat authentication is pivotal to address these concerns. The meat authenticity can be determined through genetic, protein, and immunological markers and advanced detection methods. However, these methods often target a single species and lack the specificity to distinguish closely related species. Here, in the present study, we have developed a multiplex detection method based on the species-specific primers and probes, that can target four meat species in one reaction. The developed method amplifies the mitochondrial genomic regions of chicken, pork, sheep and goat using TaqMan multiplex probe-based RT-qPCR assay. Unique pairs of species-specific primers and probes that target specific mitochondrial DNA (mtDNA) regions of each species were designed and screened for specificity and sensitivity. The detection limit for species identification using the designed primers in real-time qPCR assays was 0.1 picogram per microliter (pg/μL) DNA detected in singleplex reaction and facilitates the simultaneous detection of closely related species, such as goat and sheep. Further, DNA-based probes were utilized in a multiplex real-time qPCR assay to identify chicken, pork, sheep and goat DNA in a single tube reaction. The multiplex assay was validated for raw and processed meat products, demonstrating its applications in ensuring the quality of meat products and safeguarding consumer interests.

Prenatal arsenic exposure alters keratinocyte stem cell fate through persistent activation of IGF2R-MAPK cascade leading to aggravated skin carcinogenesis in mice offspring

Chronic exposure to arsenic (As) promotes skin carcinogenesis in humans and potentially disturbs resident stem cell dynamics, particularly during maternal and early life exposure. In the present study, we demonstrate how only prenatal arsenic exposure disturbs keratinocyte stem cell (KSC) conditioning using a BALB/c mice model. Prenatal As exposure alters the normal stemness (CD34, KRT5), differentiation (Involucrin), and proliferation (PCNA) program in skin of offspring with progression of age as observed at 2, 10, and 18 weeks. Primary KSCs isolated from exposed animal at Day-2 showed increased survival (Bax:Bcl-xL, TUNEL assay), proliferation (BrdU), and differentiation (KRT5, Involucrin) potential through the activation of pro-carcinogenic IGF2R-MAPK cascade (IGF2R-G(α)q-MEK1-ERK1/2). This was associated with reduced enrichment of histone H3K27me3 and its methylase, EZH2 along with increased binding of demethylase, KDM6A at Igf2r promoter. Altered KSCs conditioning through disturbed Igf2r imprint contributed to impaired proliferation and differentiation and an aggravated tumor response in offspring.

Metabolic engineering for enhanced terpenoid production: Leveraging new horizons with an old technique

Terpenoids are a vast class of plant specialized metabolites (PSMs) manufactured by plants and are involved in their interactions with environment. In addition, they add health benefits to human nutrition and are widely used as pharmaceutically active compounds. However, native plants produce a limited amount of terpenes restricting metabolite yield of terpene-related metabolites. Exponential growth in the plant metabolome data and the requirement of alternative approaches for producing the desired amount of terpenoids, has redirected plant biotechnology research to plant metabolic engineering, which requires in-depth knowledge and precise expertise about dynamic plant metabolic pathways and cellular physiology. Metabolic engineering is an assuring tool for enhancing the concentration of terpenes by adopting specific strategies such as overexpression of the key genes associated with the biosynthesis of targeted metabolites, controlling the modulation of transcription factors, downregulation of competitive pathways (RNAi), co-expression of the biosynthetic pathway genes in heterologous system and other combinatorial approaches. Microorganisms, fast-growing host plants (such as Nicotiana benthamiana), and cell suspension/callus cultures have provided better means for producing valuable terpenoids. Manipulation in the biosynthetic pathways responsible for synthesis of terpenoids can provide opportunities to enhance the content of desired terpenoids and open up new avenues to enhance their production. This review deliberates the worth of metabolic engineering in medicinal plants to resolve issues associated with terpenoid production at a commercial scale. However, to bring the revolution through metabolic engineering, further implementation of genome editing, elucidation of metabolic pathways using omics approaches, system biology approaches, and synthetic biology tactics are essentially needed.

Activated fibroblasts modify keratinocyte stem niche through TET1 and IL-6 to promote their rapid transformation in a mouse model of prenatal arsenic exposure

Early life exposure to environmental pollutants such as arsenic (As) can increase the risk of cancers in the offspring. In an earlier study, we showed that only prenatal As exposure significantly increases epidermal stem cell proliferation and accelerates skin tumorigenesis in BALB/c mouse offspring. In the present work, we have examined the role of As-conditioned dermal fibroblasts (DFs) in creating pro-tumorigenic niches for Keratinocyte stem cells (KSCs) in the offspring. DFs isolated from prenatally exposed animals showed increased levels of activation markers (α-SMA, Fibronectin, Collagen IV), induction of ten-eleven translocation methylcytosine dioxygenase 1(TET1), and secreted high levels of niche modifying IL-6. This led to enhanced proliferation, migration, and survival of KSCs. Increased IL-6 production in As-conditioned fibroblast was driven through TET1 mediated 5-mC to 5-hmC conversion at -698/-526 and -856/-679 region on its promoter. IL-6 further acted through downstream activation of JAK2-STAT3 signaling, promoting epithelial-to-mesenchymal transition (EMT) in KSCs. Inhibition of pSTAT3 induced by IL-6 reduced the EMT process in KSCs resulting in a significant decrease in their proliferation, migration, and colony formation. Our results indicate that IL-6 produced by prenatally conditioned fibroblasts plays a major role in regulating the KSC niche and promoting skin tumor development in As-exposed offspring.

Altered Igf2 imprint leads to accelerated adipogenesis and early onset of metabolic syndrome in male mice following gestational arsenic exposure

Developmental exposure to environmental pollutants has been shown to promote adverse health outcomes in offspring. Exposure to heavy metals such as arsenic which also has endocrine-disrupting activity is being increasingly linked with cancers, diabetes, and lately with Metabolic Syndrome (MetS). In this work, we have assessed the effects of preconceptional plus gestational arsenic exposure on the developmental programming of MetS in offspring. In our study, only gestational arsenic exposure led to reduced birth weight, followed by catch-up growth, adiposity, elevated serum triglycerides levels, and hyperglycemia in male offspring. Significant adipocyte dysfunction was observed in offspring with increased hypertrophy, insulin resistance, and chronic inflammation in epididymal white adipose tissue. Adipose tissue regulates the metabolic health of individuals and its dysfunction resulted in elevated serum levels of metabolism-regulating adipokines (Leptin, Resistin) and pro-inflammatory cytokines (PAI-1, TNFα). The progenitor adipose-derived stem cells (AdSCs) from exposed progeny had increased proliferation and adipogenic potential with excess lipid accumulation. We also found increased activation of Akt, ERK1/2 & p38 MAPK molecules in arsenic-exposed AdSCs along with increased levels of phospho-Insulin-like growth factor-1 receptor (p-IGF1R) and its upstream activator Insulin-like growth factor-2 (IGF2). Overexpression of Igf2 was found to be due to arsenic-mediated DNA hypermethylation at the imprinting control region (ICR) located -2kb to -4.4 kb upstream of the H19 gene which caused a reduction in the conserved zinc finger protein (CTCF) occupancy. This further led to persistent activation of the MAPK signaling cascade and enhanced adipogenesis leading to the early onset of MetS in the offspring.

Chitosan/alginate nanogel potentiate berberine uptake and enhance oxidative stress mediated apoptotic cell death in HepG2 cells

Biopolymer-based nanoscale drug delivery systems have become a promising approach to overcome the limitations associated with conventional chemotherapeutics used for cancer treatment. Herein, we reported to develop a hydrophilic nanogel (NG) composed of Chitosan (Chi) and sodium alginate (Alg) using the ion gelation method for delivering Berberine hydrochloride (BBR), an alkaloid obtained from Berberis aristata roots. The use of different nanocarriers for BBR delivery has been reported previously, but the bioavailability of these carriers was limited due to phagocytic uptake and poor systemic delivery. The developed NG showed enhanced stability and efficient entrapment of BBR ∼92 %, resulting in a significant increase in bioavailability. The pH-dependent release behavior demonstrated sustained and effective release of ∼86 %, ∼74 % and, ∼53 % BBR at pH 5.5, 6.6, and 7.4 respectively after 72h, indicating its potential as a drug carrier. Additionally, the cellular uptake of BBR was significantly higher ∼19 % in the BBR-NG (25 μM) than in bulk BBR (100 μM), leading to enhanced ROS generation, mitochondrial depolarisation, and inhibition of cell proliferation and colony formation in HepG2 cells. In summary, the results suggest that the Chi/Alg biopolymer-based nano-formulation could be an effective approach for delivering BBR and enhancing its cellular uptake, efficacy, and cytotoxicity.

Development of an immunoassay for the detection of mycotoxins using xMAP technology and its evaluation in black tea samples

Mycotoxins, a natural food contaminant, are secondary metabolites of fungi. Aflatoxin B1 (AFB1) and ochratoxin A (OTA) are two major mycotoxins found in various food commodities. These mycotoxins are hepatotoxic, nephrotoxic, cytotoxic, mutagenic and carcinogenic, thus they are a public health concern and their monitoring in food commodities is necessary. There are several conventional techniques available for mycotoxin detection, such as HPLC, LCMS, and ELISA. However, extensive nature and huge cost allowances make it challenging to deploy these techniques for monitoring of mycotoxins in the large sample size. Therefore, a robust, responsive and high-throughput technique is required. Here, we aimed to develop a multiplexed Luminex suspension assay based on multi analyte profiling (xMAP) technology for the simultaneous detection of AFB1 and OTA in the black tea, which is found to be contaminated with these mycotoxins during the cultivation or processing steps. Limit of detection for AFB1 and OTA, was 0.06 ng/ml and 0.49 ng/ml, respectively without any cross-reactivity with other mycotoxins and this assay is suitable for simultaneous detection of AFB1 and OTA in the same sample. Collectively, based on the results, we suggest that the developed Luminex suspension assay is sensitive, accurate, rapid and suitable for high-throughput screening of multiple mycotoxins.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05848-3.

Organ support in sepsis: A panoramic view from infection to death

Despite significant advancements in medical research, sepsis persists as a leading cause of mortality in intensive care units (ICUs). Sepsis intricately contributes to organ failure, amplifying both morbidity and mortality. In these instances, a comprehensive comprehension of the physiology of each organ is imperative for accurate diagnosis and effective management. Within the context of an ICU clinical scenario, a meticulous evaluation and monitoring of six pivotal organ systems cardiovascular, renal, respiratory, neurological, hematological, and hepatic are essential. The primary objective in managing sepsis-induced organ failure is the early detection and intervention, encompassing timely administration of antibiotics, identification and control of the infection source, and implementation of supportive therapy. Despite the extensive body of medical literature, there is a conspicuous absence of evidence-based multi-organ management strategies for such patients. The intricate interplay between organs, commonly referred to as organ crosstalk, presents a formidable challenge in navigating the complexities of sepsis management.

A case of relapsing anti-GBM disease secondary to alemtuzumab therapy

We report the first case of relapsing anti-GBM disease secondary to alemtuzumab in a 24-year-old female with relapsing-remitting multiple sclerosis. Initial anti-GBM disease was detected 10 months after alemtuzumab was given and was diagnosed by demonstrating high anti-GBM antibody titers and with a confirmatory kidney biopsy. The patient presented with a rapidly progressive glomerulonephritis with no pulmonary involvement. After appropriate treatment, the patient went into remission with undetectable anti-GBM antibodies. However, 20 months later, the patient re-presented with relapsing anti-GBM disease. Despite aggressive treatment, the patient became dialysis-dependent.

Graphene oxide nanosheets augment silk fibroin aerogels for enhanced water stability and oil adsorption

Nanocomposite aerogels exhibit high porosity and large interfacial surface areas, enabling enhanced chemical transport and reactivity. Such mesoporous architectures can be prepared by freeze-casting naturally-derived biopolymers such as silk fibroin, but often form mechanically weak structures that degrade in water, which limits their performance under ambient conditions. Adding 2D material fillers such as graphene oxide (GO) or transition metal carbides (e.g. MXene) could potentially reinforce these aerogels via stronger intermolecular interactions with the polymeric binder. Here, we show that freeze-casting of GO nanosheets with silk fibroin results in a highly water-stable, mechanically robust aerogel, with considerably enhanced properties relative to silk-only or silk-MXene aerogels. These silk-GO aerogels exhibit high contact angles with water and are highly water stable. Moreover, aerogels can adsorb up 25-35 times their mass in oil, and can be used robustly for selective oil separation from water. This increased stability may occur due to strengthened intermolecular interactions such as hydrogen bonding, despite the random coil and α-helix conformation of silk fibroin, which is typically more soluble in water. Finally, we show these aerogels can be prepared at scale by freeze-casting on a copper mesh. Ultimately, we envision that these multicomponent aerogels could be widely utilized for molecular separations and environmental sensing, as well as for thermal insulation and electrical conductivity.

Performance enhancement in clustering cooperative spectrum sensing for cognitive radio network using metaheuristic algorithm

Spectrum sensing describes, whether the spectrum is occupied or empty. Main objective of cognitive radio network (CRN) is to increase probability of detection (Pd) and reduce probability of error (Pe) for energy consumption. To reduce energy consumption, probability of detection should be increased. In cooperative spectrum sensing (CSS), all secondary users (SU) transmit their data to fusion center (FC) for final measurement according to the status of primary user (PU). Cluster should be used to overcome this problem and improve performance. In the clustering technique, all SUs are grouped into clusters on the basis of their similarity. In cluster technique, SU transfers their data to cluster head (CH) and CH transfers their combined data to FC. This paper proposes the detection performance optimization of CRN with a machine learning-based metaheuristic algorithm using clustering CSS technique. This article presents a hybrid support vector machine (SVM) and Red Deer Algorithm (RDA) algorithm named Hybrid SVM-RDA to identify spectrum gaps. Algorithm proposed in this work outperforms the computational complexity, an issue reported with various conventional cluster techniques. The proposed algorithm increases the probability of detection (up to 99%) and decreases the probability of error (up to 1%) at different parameters.

Increasing Chemotherapeutic Efficacy Using pH-Modulating and Doxorubicin-Releasing Injectable Chitosan-Poly(ethylene glycol) Hydrogels

Modulation of pH is crucial to maintaining the chemical homeostasis of biological environments. The irregular metabolic pathways exhibited by cancer cells result in the production of acidic byproducts that are excreted and accumulate in the extracellular tumor microenvironment, reducing the pH. As a consequence of the lower pH in tumors, cancer cells increase the expression of metastatic phenotypes and chemotherapeutic resistance. A significant limitation in current cancer therapies is the inability to locally deliver chemotherapeutics, leading to significant damage to healthy cells in systemic administration. To overcome these challenges, we present an injectable chitosan-poly(ethylene glycol) hydrogel that is dual-loaded with doxorubicin and sodium bicarbonate providing alkaline buffering of extracellular acidity and simultaneous chemotherapeutic delivery to increase chemotherapeutic efficacy. We conducted in vitro studies of weak base chemotherapeutic and alkaline buffer release from the hydrogel. The release of doxorubicin from hydrogels increased in a low-pH environment and was dependent on the encapsulated sodium bicarbonate concentration. We investigated the influence of pH on the doxorubicin efficacy and viability of MCF-7 and MDA-MB-231 breast cancer cell lines. The results show a 2- to 3-fold increase in IC50 values from neutral pH to low pH, showing decreased cancer cell viability at neutral pH as compared to acidic pH. The IC50 results were shown to correlate with a decrease in intracellular uptake of doxorubicin at low pH. The proposed hydrogels were confirmed to be nontoxic to healthy MCF-10A mammary epithelial cells. Rheological studies were performed to verify that the dual-loaded hydrogels were injectable. The mechanical and release properties of the hydrogels were maintained after extended storage. The chemotherapeutic activity of doxorubicin was evaluated in the presence of the proposed pH-regulating hydrogels. The findings suggest a promising nontoxic, biodegradable hydrogel buffer delivery system that can achieve two simultaneous important goals of local acidosis neutralization and chemotherapeutic release.

Plant salinity stress, sensing, and its mitigation through WRKY

Salinity or salt stress has deleterious effects on plant growth and development. It imposes osmotic, ionic, and secondary stresses, including oxidative stress on the plants and is responsible for the reduction of overall crop productivity and therefore challenges global food security. Plants respond to salinity, by triggering homoeostatic mechanisms that counter salt-triggered disturbances in the physiology and biochemistry of plants. This involves the activation of many signaling components such as SOS pathway, ABA pathway, and ROS and osmotic stress signaling. These biochemical responses are accompanied by transcriptional modulation of stress-responsive genes, which is mostly mediated by salt-induced transcription factor (TF) activity. Among the TFs, the multifaceted significance of WRKY proteins has been realized in many diverse avenues of plants' life including regulation of plant stress response. Therefore, in this review, we aimed to highlight the significance of salinity in a global perspective, the mechanism of salt sensing in plants, and the contribution of WRKYs in the modulation of plants' response to salinity stress. This review will be a substantial tool to investigate this problem in different perspectives, targeting WRKY and offering directions to better manage salinity stress in the field to ensure food security.

Analysis of gut bacteriome of in utero arsenic-exposed mice using 16S rRNA-based metagenomic approach

Introduction

Approximately 200 million people worldwide are affected by arsenic toxicity emanating from the consumption of drinking water containing inorganic arsenic above the prescribed maximum contaminant level. The current investigation deals with the role of prenatal arsenic exposure in modulating the gut microbial community and functional pathways of the host.

Method

16S rRNA-based next-generation sequencing was carried out to understand the effects of in utero 0.04 mg/kg (LD) and 0.4 mg/kg (HD) of arsenic exposure. This was carried out from gestational day 15 (GD-15) until the birth of pups to understand the alterations in bacterial diversity.

Results

The study focused on gestational exposure to arsenic and the altered gut microbial community at phyla and genus levels, along with diversity indices. A significant decrease in firmicutes was observed in the gut microbiome of mice treated with arsenic. Functional analysis revealed that a shift in genes involved in crucial pathways such as insulin signaling and non-alcoholic fatty liver disease pathways may lead to metabolic diseases in the host.

Discussion

The present investigation may hypothesize that in utero arsenic exposure can perturb the gut bacterial composition significantly as well as the functional pathways of the gestationally treated pups. This research paves the way to further investigate the probable mechanistic insights in the field of maternal exposure environments, which may play a key role in epigenetic modulations in developing various disease endpoints in the progeny.

Metabolic engineering in hairy roots: An outlook on production of plant secondary metabolites

Plants are one of the vital sources of secondary metabolites. These secondary metabolites have diverse roles in human welfare, including therapeutic implication. Nevertheless, secondary metabolite yields obtained through the exploitation of natural plant populations is insufficient to meet the commercial demand due to their accumulation in low volumes. Besides, in-planta synthesis of these important metabolites is directly linked with the age and growing conditions of the plant. Such limitations have paved the way for the exploration of alternative production methodologies. Hairy root cultures, induced after the interaction of plants with Rhizobium rhizogenes (Agrobacterium rhizogenes), are a practical solution for producing valuable secondary metabolite at low cost and without the influence of seasonal, geographic or climatic variations. Hairy root cultures also offer the opportunity to get combined with other yield enhancements strategies (precursor feeding, elicitation and metabolic engineering) to further stimulate and/or enhance their production potential. Applications of metabolic engineering in exploiting hairy root cultures attracted the interest of several research groups as a means of yield enhancement. Currently, several engineering approaches like overexpression and silencing of pathway genes, and transcription factor overexpression are used to boost metabolite production, along with the contextual success of genome editing. This review attempts to cover metabolic engineering in hairy roots for the production of secondary metabolites, with a primary emphasis on alkaloids, and discusses prospects for taking this research forward to meet desired production demands.

The nuclear effector ArPEC25 from the necrotrophic fungus Ascochyta rabiei targets the chickpea transcription factor CaβLIM1a and negatively modulates lignin biosynthesis, increasing host susceptibility

Fungal pathogens deploy a barrage of secreted effectors to subvert host immunity, often by evading, disrupting, or altering key components of transcription, defense signaling, and metabolic pathways. However, the underlying mechanisms of effectors and their host targets are largely unexplored in necrotrophic fungal pathogens. Here, we describe the effector protein Ascochyta rabiei PEXEL-like Effector Candidate 25 (ArPEC25), which is secreted by the necrotroph A. rabiei, the causal agent of Ascochyta blight disease in chickpea (Cicer arietinum), and is indispensable for virulence. After entering host cells, ArPEC25 localizes to the nucleus and targets the host LIM transcription factor CaβLIM1a. CaβLIM1a is a transcriptional regulator of CaPAL1, which encodes phenylalanine ammonia lyase (PAL), the regulatory, gatekeeping enzyme of the phenylpropanoid pathway. ArPEC25 inhibits the transactivation of CaβLIM1a by interfering with its DNA-binding ability, resulting in negative regulation of the phenylpropanoid pathway and decreased levels of intermediates of lignin biosynthesis, thereby suppressing lignin production. Our findings illustrate the role of fungal effectors in enhancing virulence by targeting a key defense pathway that leads to the biosynthesis of various secondary metabolites and antifungal compounds. This study provides a template for the study of less explored necrotrophic effectors and their host target functions.

Innovative Spectrum Handoff Process Using a Machine Learning-Based Metaheuristic Algorithm

A cognitive radio network (CRN) is an intelligent network that can detect unoccupied spectrum space without interfering with the primary user (PU). Spectrum scarcity arises due to the stable channel allocation, which the CRN handles. Spectrum handoff management is a critical problem that must be addressed in the CRN to ensure indefinite connection and profitable use of unallocated spectrum space for secondary users (SUs). Spectrum handoff (SHO) has some disadvantages, i.e., communication delay and power consumption. To overcome these drawbacks, a reduction in handoff should be a priority. This study proposes the use of dynamic spectrum access (DSA) to check for available channels for SU during handoff using a metaheuristic algorithm depending on machine learning. The simulation results show that the proposed "support vector machine-based red deer algorithm" (SVM-RDA) is resilient and has low complexity. The suggested algorithm's experimental setup offers several handoffs, unsuccessful handoffs, handoff delay, throughput, signal-to-noise ratio (SNR), SU bandwidth, and total spectrum bandwidth. This study provides an improved system performance during SHO. The inferred technique anticipates handoff delay and minimizes the handoff numbers. The results show that the recommended method is better at making predictions with fewer handoffs compared to the other three.

Prenatal arsenic exposure induces immunometabolic alteration and renal injury in rats

Arsenic (As) exposure is progressively associated with chronic kidney disease (CKD), a leading public health concern present worldwide. The adverse effect of As exposure on the kidneys of people living in As endemic areas have not been extensively studied. Furthermore, the impact of only prenatal exposure to As on the progression of CKD also has not been fully characterized. In the present study, we examined the effect of prenatal exposure to low doses of As 0.04 and 0.4 mg/kg body weight (0.04 and 0.4 ppm, respectively) on the progression of CKD in male offspring using a Wistar rat model. Interestingly, only prenatal As exposure was sufficient to elevate the expression of profibrotic (TGF-β1) and proinflammatory (IL-1α, MIP-2α, RANTES, and TNF-α) cytokines at 2-day, 12- and 38-week time points in the exposed progeny. Further, alteration in adipogenic factors (ghrelin, leptin, and glucagon) was also observed in 12- and 38-week old male offspring prenatally exposed to As. An altered level of these factors coincides with impaired glucose metabolism and homeostasis accompanied by progressive kidney damage. We observed a significant increase in the deposition of extracellular matrix components and glomerular and tubular damage in the kidneys of 38-week-old male offspring prenatally exposed to As. Furthermore, the overexpression of TGF-β1 in kidneys corresponds with hypermethylation of the TGF-β1 gene-body, indicating a possible involvement of prenatal As exposure-driven epigenetic modulations of TGF-β1 expression. Our study provides evidence that prenatal As exposure to males can adversely affect the immunometabolism of offspring which can promote kidney damage later in life.

Gestational exposure to silver nanoparticles enhances immune adaptation and protection against streptozotocin-induced diabetic nephropathy in mice offspring

Silver nanoparticles (AgNPs) possess unique antimicrobial properties. As a result, they are being increasingly used in a wide range of applications. Several studies have shown detrimental effects of AgNPs exposure, including inflammation, accumulation, and cellular damage to different organs. However, the effect of AgNPs exposure during gestation, a critical and susceptible period of human development, on pregnant females and its long-term effects on offspring's health has not been studied. Therefore, we conducted a long-term study where we assessed the effect of gestational AgNPs exposure on pregnant mice and followed their offspring until the age of 12 months. Gestational exposure to AgNPs induced systemic inflammation in the pregnant mice at gestational day (GD) 18. Interestingly, developing fetuses exposed to AgNPs, showed anti-inflammatory conditions as indicated by reduced expression of inflammatory genes in fetal organs at GD 18 and reduced serum levels of TNF-α, IFN-γ, IL-17A, IL-6, and MCP-1 in AgNPs exposed pups at postnatal day (PD) 2. Surprisingly, post-weaning, AgNPs exposed offspring showed a heightened immune activation as shown by upregulation of inflammatory cytokines at PD 28, which persisted till late in life. Moreover, we observed metabolic alterations which persisted until adulthood in mice. To understand the impact of long-term immunometabolic changes on the progression of diabetes and kidney diseases under stressed conditions, we exposed offspring to streptozotocin which revealed a protective role of low-dose gestational AgNPs exposure against streptozotocin-induced diabetes and associated nephropathy.

Search for Subsolar-Mass Binaries in the First Half of Advanced LIGO's and Advanced Virgo's Third Observing Run

We report on a search for compact binary coalescences where at least one binary component has a mass between 0.2  M_{⊙} and 1.0  M_{⊙} in Advanced LIGO and Advanced Virgo data collected between 1 April 2019 1500 UTC and 1 October 2019 1500 UTC. We extend our previous analyses in two main ways: we include data from the Virgo detector and we allow for more unequal mass systems, with mass ratio q≥0.1. We do not report any gravitational-wave candidates. The most significant trigger has a false alarm rate of 0.14  yr^{-1}. This implies an upper limit on the merger rate of subsolar binaries in the range [220-24200]  Gpc^{-3} yr^{-1}, depending on the chirp mass of the binary. We use this upper limit to derive astrophysical constraints on two phenomenological models that could produce subsolar-mass compact objects. One is an isotropic distribution of equal-mass primordial black holes. Using this model, we find that the fraction of dark matter in primordial black holes in the mass range 0.2  M_{⊙}<m_{PBH}<1.0  M_{⊙} is f_{PBH}≡Ω_{PBH}/Ω_{DM}≲6%. This improves existing constraints on primordial black hole abundance by a factor of ∼3. The other is a dissipative dark matter model, in which fermionic dark matter can collapse and form black holes. The upper limit on the fraction of dark matter black holes depends on the minimum mass of the black holes that can be formed: the most constraining result is obtained at M_{min}=1  M_{⊙}, where f_{DBH}≡Ω_{DBH}/Ω_{DM}≲0.003%. These are the first constraints placed on dissipative dark models by subsolar-mass analyses.

A study on bisphenol S induced nephrotoxicity and assessment of altered downstream kidney metabolites using gas chromatography-mass spectrometry based metabolomics

The global use of bisphenol S (BPS) has now been significantly increased for commensurate utilization as a substitute for BPA for its regulatory concerns. Though, previous reports indicated that BPS been also appeared as a toxic congener comparable to BPA. In the present study, we determined nephrotoxicity condition induced due to BPS exposure. Results indicated that BPS significantly promoted histopathological disturbance in the kidney, and altered the levels of biomarkers of kidney damage in serum and urine samples of Wistar rats. It is also indicated that BPS altered the expression of kidney damage biomarkers associated with glomerular and tubular injury. Additionally, we determined the perturbation of kidney metabolites in the underlying pathophysiological response of kidney injury due to BPS exposure. Gas chromatography-mass spectrometry based untargeted metabolomics exhibited 20 significantly perturbed metabolites. Moreover, metabolic pathway analysis revealed significant disturbance in the TCA cycle and pyruvate metabolism pathways.

Hydrogen sulphide-mediated alleviation and its interplay with other signalling molecules during temperature stress

The sessile habit of plants does not provide choices to escape the environmental constraints, leading to negative impacts on their growth and development. This causes significant losses in the agriculture sector and raises serious issues on global food security. Extreme temperatures (high or low) influence several aspects of plant life and can cause reproduction malfunction. Therefore, a strategy for temperature amelioration is necessary for the management of agricultural productivity. Supplementation with various chemicals (e.g. phytohormones, gasotransmitters, osmolytes) is considered a good choice to manage plant stress. Gasotransmitters are well-recognized for stress mitigation in plants, among which hydrogen sulphide (H₂ S) has proved promising to alleviate stress. Temperature (heat/cold) stress can stimulate the endogenous production of H₂ S in plants, and many studies have reported the significance of H₂ S for temperature stress amelioration. Here, H₂ S led to positive changes in plant physiological, biochemical and molecular responses, which are usually compromised during stress. Further, H₂ S also coordinate with other signalling components that act either upstream or downstream during stress mitigation. This review focuses on the significance of H₂ S for mitigation of temperature stress, with a comprehensive discussion on cross-talk with other signalling components or supplements (e.g. NO, H₂ O₂ , salicylic acid, trehalose, proline). Finally, the review provides a rational assessment and holistic understanding of H₂ S-mediated mitigation of extreme temperature stress and addresses the prospects for development of an effective strategy to manage temperature stress.

Developmental Exposure to Endocrine Disrupting Chemicals and Its Impact on Cardio-Metabolic-Renal Health

Developmental origin of health and disease postulates that the footprints of early life exposure are followed as an endowment of risk for adult diseases. Epidemiological and experimental evidence suggest that an adverse fetal environment can affect the health of offspring throughout their lifetime. Exposure to endocrine disrupting chemicals (EDCs) during fetal development can affect the hormone system homeostasis, resulting in a broad spectrum of adverse health outcomes. In the present review, we have described the effect of prenatal EDCs exposure on cardio-metabolic-renal health, using the available epidemiological and experimental evidence. We also discuss the potential mechanisms of their action, which include epigenetic changes, hormonal imprinting, loss of energy homeostasis, and metabolic perturbations. The effect of prenatal EDCs exposure on cardio-metabolic-renal health, which is a complex condition of an altered biological landscape, can be further examined in the case of other environmental stressors with a similar mode of action.

Shape Memory Nitinol Based Minimally Invasive Spinal Cord Stimulation Device Concept for Improved Pain Management

BACKGROUND

Spinal cord stimulation (SCS) is a common treatment for neuropathic pain. There are 2 main categories of SCS leads: paddle leads and cylindrical leads. Paddle leads have reduced long-term complications and provide better coverage of target dermatomes when compared to cylindrical leads. However, insertion of a paddle lead requires invasive surgery that comes with significantly higher costs and more short-term complications, such as postoperative pain and infection. In contrast, cylindrical leads can be inserted minimally invasively using percutaneous techniques but provide less coverage of targeted dermatomes and have a higher tendency to migrate from intended neuronal targets.

OBJECTIVES

Our objective is to develop a novel improved cylindrical spinal cord stimulation device that can convert into an optimal geometry once exposed to the body's environment after minimally invasive surgery. Such a device would be able to reduce long-term complications, lead migration, and better cover targeted dermatomes.

STUDY DESIGN

Biomaterial selection, medical intervention device design with an in-vitro lab-scale test, and cadaveric experimental study.

METHODS

A shape memory alloy nitinol-based cylindrical lead was designed, and its nitinol core material was processed and geometrically programmed for percutaneous insertion into the epidural space and morphing into an optimal geometry once exposed to the body's environment. Deployment of the nitinol component of the design was tested in the lab and human cadaveric models of the epidural space.

RESULTS

Deployment of the nitinol component of the proposed cylindrical lead was successfully demonstrated in both a lab model of the epidural space and in the epidural space of a human cadaver in a minimally invasive fashion, indicating that a similar component could be used clinically in a full SCS electrode manufactured in a custom final geometry.

LIMITATIONS

The focus of this study was to test the deployment of a novel minimally invasive lead that provides optimal coverage of intended dermatomes using in-vitro methods. Our study does not include in vivo trials. We do not test the electrical components of the design proposed since our design does not make changes to the electrical components of current commercially used cylindrical leads.

CONCLUSION

The unique shape memory property of nitinol shows promise in allowing cylindrical spinal cord stimulation leads to expand into a more optimal geometry within the epidural space. By having a body temperature-dependent geometry change, nitinol-based cylindrical leads could reduce lead migration, increase dermatomal coverage, and increase electrode density while maintaining the advantages of minimally invasive insertion.

Hydrogen sulfide-mediated mitigation and its integrated signaling crosstalk during salinity stress

Environmental stresses negatively affect plant development and significantly influence global agricultural productivity. The growth suppression due to soil salinity involves osmotic stress, which is accompanied by ion toxicity, nutritional imbalance, and oxidative stress. The amelioration of salinity stress is one of the fundamental goals to be achieved to ensure food security and better meet the issues related to global hunger. The application of exogenous chemicals is the imperative and efficient choice to alleviate stress in the agricultural field. Among them, hydrogen sulfide (H₂ S, a gasotransmitter) is known for its efficient role in stress mitigation, including salinity stress, along with other biological features related to growth and development in plants. H₂ S plays a role in improving photosynthesis and ROS homeostasis, and interacts with other signaling components in a cascade fashion. The current review gives a comprehensive view of the participation of H₂ S in salinity stress alleviation in plants. Further, its crosstalk with other stress ameliorating signaling component or supplement (e.g., NO, H₂ O₂ , melatonin) is also covered and discussed. Finally, we discuss the possible prospects to meet with success in agricultural fields.

A human arterial transcriptomic signature predicts major adverse cardiac events and identifies novel, redox-related therapeutic targets within the vascular wall

Background

The transcriptomic profile of the human vascular wall is implicated in a range of pathologies. RNA sequencing technologies allow for interrogation of gene expression patterns that are associated with clinical outcomes and can guide future research and drug development.

Purpose

To apply discovery network transcriptomics to internal mammary arteries (IMAs) obtained from patients undergoing cardiac surgery, in order to identify redox-related molecular pathways within the vascular wall that can be treated therapeutically.

Methods

Arm 1 included 377 patients in whom segments of IMA were used for ex-vivo quantification of NADPH-stimulated superoxide production by lucigenin-enhanced chemiluminescence. Arm 2 included 205 patients in whom bulk RNA sequencing was performed in RNA isolated from IMA, and the WGCNA package used for the analyses. The association with future incidence of major adverse cardiac events (MACE: cardiovascular death, non-fatal myocardial infarction, and stroke) was assessed using Cox regression models (adjusted for age, sex, hypertension, dyslipidaemia, diabetes mellitus, body mass index, smoking, and plasma TNFa).

Results

Over a median follow-up of 4.84 years [IQR: 2.03–7.14], 38 (11.2%) MACE occurred in Arm 1. High arterial NADPH-stimulated superoxide was independently associated with MACE risk (Adj. HR [95% CI]: 2.62 [1.13–6.07] high group, p=0.02). Unsupervised transcriptomic analysis in Arm 2 allowed identification of 10 coexpressed gene “modules”. Eigengenes summarising modular coexpression signatures were then correlated with NADPH-stimulated superoxide revealing the red module (a) as the most significant (rho=0.19, p=0.01). In survival analysis the red module showed significant correlation with MACE (Adj. HR [95% CI]: 1.40 [1.00–1.95] per SD, p=0.04). For an optimal cut-off, patients with high eigengene values for the red module showed a 4-fold higher risk of MACE (b), and significantly higher arterial oxidative stress (c). Enrichment analysis (performed with Enrichr) of genes in the red module revealed “Electron Transport Chain”, “Oxidative phosphorylation”, “Striated Muscle Contraction Pathway”, and “Glycolysis and Gluconeogenesis” amongst the top enriched pathways (d).

Conclusion

We present for the first time a novel human arterial transcriptomic signature reflecting changes in redox state, which identifies long-term cardiovascular risk. Targeting pathways in the vasculature related with the mitochondrial electron transport chain, the contractile mechanism, or glucose metabolism may lead to the development of novel therapeutics in cardiovascular disease.

Funding Acknowledgement

Type of funding sources: Foundation. Main funding source(s): EPSRC-EP/N509711/1-2119518British Heart Foundation Figure 1

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Constraints on Cosmic Strings Using Data from the Third Advanced LIGO-Virgo Observing Run

We search for gravitational-wave signals produced by cosmic strings in the Advanced LIGO and Virgo full O3 dataset. Search results are presented for gravitational waves produced by cosmic string loop features such as cusps, kinks, and, for the first time, kink-kink collisions. A template-based search for short-duration transient signals does not yield a detection. We also use the stochastic gravitational-wave background energy density upper limits derived from the O3 data to constrain the cosmic string tension Gμ as a function of the number of kinks, or the number of cusps, for two cosmic string loop distribution models. Additionally, we develop and test a third model that interpolates between these two models. Our results improve upon the previous LIGO-Virgo constraints on Gμ by 1 to 2 orders of magnitude depending on the model that is tested. In particular, for the one-loop distribution model, we set the most competitive constraints to date: Gμ≲4×10^{-15}. In the case of cosmic strings formed at the end of inflation in the context of grand unified theories, these results challenge simple inflationary models.

Micro/nano-machines for spilled-oil cleanup and recovery: A review

High-efficiency, safe and economically viable nano-engineered platforms for oil spill cleanup and recovery are of great importance. This review takes account of the concept of nanomotors and micromotors and their most advancements in use for oil spill treatment. The fundamental facets of artificial micro- and nano-machines/nanobots/nanomotors (MNMs) are first documented, followed by the most recent influencing developments in chemical engineering approaches toward their specific utilizations. The surface chemistry of these MNMs, their behaviors in different water matrices and their roles in the removal of oil are examined, revealing great rooms for improvement. The strategies for surface and structural modification of these tiny machines toward enhancing their reactivity in the removal of oil and coupled tasking are discussed in details, highlighting the significance of fit-for-duty design and tailored fabrication. The engineering limitations and practical implementation barriers of this emerging technology and how it can be overcome are also considered. Finally, some engineering boundaries and perspectives of this fast-evolving field are proposed at the end.

Perinatal exposure to silver nanoparticles reprograms immunometabolism and promotes pancreatic beta-cell death and kidney damage in mice

Silver nanoparticles (AgNPs) are extensively utilized in food, cosmetics, and healthcare products. Though the effects of AgNPs exposure on adults are well documented, the long-term effects of gestational/perinatal exposure upon the health of offspring have not been addressed. Herein, we show that only perinatal exposure to AgNPs through the mother could lead to chronic inflammation in offspring which persists till adulthood. Further, AgNPs exposure altered offspring's immune responses against environmental stresses. AgNPs exposed offspring showed an altered response in splenocyte proliferation assay when challenged to lipopolysaccharide, concanavalin-A, AgNPs, or silver ions. Perinatal AgNPs exposure affected metabolic parameters (resistin, glucagon-like peptide-1, leptin, insulin) and upregulated JNK/P38/ERK signaling in the pancreas. We observed pancreatic damage, reduced insulin level, and increased blood glucose levels. Further, we observed renal damage, particularly to tubular and glomerular regions as indicated by histopathology and electron microscopy. Our study thus shows that only perinatal exposure to AgNPs could induce persistent inflammation, alter immune responses against foreign antigens and metabolism which may contribute to pancreatic and renal damage later in life.

Optimal management of brain-dead organ donor

Maintaining a brain stem-dead (BSD) donor is specialized science. It is a daunting task as they are fragile patients who need to be handled with utmost care owing to extreme haemodynamically instability and need the best of monitoring for maintenance of organs. To ensure a successful transplant, a BSD donor first needs to be identified on time. This requires scrupulous monitoring of neurologically compromised patients who tend to be the most frequent organ donors. Once the donor is identified, an all-out effort should be made to legally obtain consent for the donation. This may require numerous sessions of counselling of the relatives. It needs to be performed tactfully, displaying the best of intentions. It is important to understand the physiology of a brain-dead individual. A cascade of changes occurs in BSD donor which result in a catastrophic plummeting of the clinical condition of the donor. All organ systems are involved in this clinical chaos, and best possible clinical support of all organ systems should be available and extended to the donor. Organ support includes cardiovascular, pulmonary, temperature, glycaemic, metabolic and hormonal. This article has been written as a follow-up article of previously published article on identifying an organ donor. It intends to give the reader a concept of what the BSD donor undergoes after brain death and as to how to maintain and preserve various organs for donation for successful transplantation of maximum organs.

Reduced rotavirus vaccine efficacy in protein malnourished human-faecal-microbiota-transplanted gnotobiotic pig model is in part attributed to the gut microbiota

The low efficacy of human rotavirus (HRV) vaccines in low- and middle-income countries (LMIC) remains a major challenge for global health. Protein-calorie malnutrition (kwashiorkor) affects the gut microbiota and compromises immune development, leading to environmental enteropathy, vaccine failures, and increased susceptibility to enteric diseases in young children. Relationship between diet and reduced vaccine efficacy in developing countries is not well established; therefore, we investigated the interconnections between the host-microbiota-nutrition-HRV vaccine using HRV-vaccinated, human infant faecal microbiota (HIFM)-transplanted neonatal gnotobiotic pigs fed with a protein deficient or sufficient diet. The microbiota from faecal, intestinal (duodenum, ileum, jejunum, and colon), and systemic tissue (liver, spleen, and mesenteric lymph node [MLN]) samples was analysed before and after HRV challenge using MiSeq 16S rRNA sequencing. Overall, microbiota from deficient fed HIFM pigs displayed, compared to the sufficient group, significantly higher Shannon index, especially in the faeces and lower intestines; higher level of Proteus and Enterococcus, and lower level of Bifidobacterium, Clostridium, and Streptococcus in the three types of samples collected (P<0.05); and higher unique operational taxonomic units (OTUs), especially in the systemic tissues. Further, the multivariate analysis between microbiota and immunologic data showed that 38 OTUs at the genus level correlated (r²≤0.5 or ≥-0.5; P<0.05) with at least one host immune response parameter (regulatory [Tregs and transforming growth factor-β], effectors [interferon (IFN)-γ⁺ CD4⁺ and CD8⁺ T cells, IFN-γ and interleukin (IL)-12], and inflammatory [tumour necrosis factor-α, IL-17 and IL-22]) and with opposite trends between diet groups. Differences described above were increased after HRV challenge. We demonstrated that a protein deficient diet affects the composition of the gut microbiota and those changes may further correlate with immune responses induced by HRV and perturbed by the deficient diet. Thus, our findings suggest that the reduced efficacy of HRV vaccine observed in Gn pig model is in part attributed to the altered microbiota composition.

GW190521: A Binary Black Hole Merger with a Total Mass of 150 M_{⊙}

On May 21, 2019 at 03:02:29 UTC Advanced LIGO and Advanced Virgo observed a short duration gravitational-wave signal, GW190521, with a three-detector network signal-to-noise ratio of 14.7, and an estimated false-alarm rate of 1 in 4900 yr using a search sensitive to generic transients. If GW190521 is from a quasicircular binary inspiral, then the detected signal is consistent with the merger of two black holes with masses of 85_{-14}^{+21}  M_{⊙} and 66_{-18}^{+17}  M_{⊙} (90% credible intervals). We infer that the primary black hole mass lies within the gap produced by (pulsational) pair-instability supernova processes, with only a 0.32% probability of being below 65  M_{⊙}. We calculate the mass of the remnant to be 142_{-16}^{+28}  M_{⊙}, which can be considered an intermediate mass black hole (IMBH). The luminosity distance of the source is 5.3_{-2.6}^{+2.4}  Gpc, corresponding to a redshift of 0.82_{-0.34}^{+0.28}. The inferred rate of mergers similar to GW190521 is 0.13_{-0.11}^{+0.30}  Gpc^{-3} yr^{-1}.

Survey of Australasian Renal and Rheumatology Specialists investigating topical NSAID use and adverse renal outcomes

INTRODUCTION

A survey investigated physician reported use, prescribing practices and adverse renal events of topical NSAIDs.

METHOD

This survey was sent to members of the Australian Rheumatology Association and the Australian and New Zealand Society of Nephrology.

RESULTS

Sixty physicians responded, 55% (n = 33) were nephrologists; 45% (n = 27) rheumatologists. Nearly all (n = 56, 93.3%) had managed at least one patient using topical NSAIDs, including those with an eGFR <45 mL/min (n = 55, 91.7%). Concern was expressed that patients may use topical NSAIDs without the physician's knowledge. The majority (n = 40, 66.6%) have prescribed (or recommended) a topical NSAID, slightly less in patients with a reduced eGFR <45 mL/min (n = 36, 60.0%). Participants would advise topical NSAIDs for osteoarthritis and musculoskeletal pain, though be mindful to monitor the renal function and blood pressure. There was a variance in comments in advising use in CKD (eGFR <45 mL/min) from avoidance in those with an eGFR <30 mL/min to minimal concern. Most respondents (n = 55, 91.7%) had not encountered an acute kidney injury (AKI) suspected from topical NSAID use. Of the five that did, three were thought to be an adverse renovascular event and two were uncertain. All patients had an eGFR <45 mL/min, all had recovery f their renal function with NSAID cessation.

DISCUSSION

Patients commonly use topical NSAIDs, often without the physician's knowledge. Most respondents would recommend their use in osteoarthritis and musculoskeletal pain, though with caution in CKD. While an AKI is uncommon due to topical NSAIDs, it may occur, especially in those with CKD.

Prospects for observing and localizing gravitational-wave transients with Advanced LIGO, Advanced Virgo and KAGRA

We present our current best estimate of the plausible observing scenarios for the Advanced LIGO, Advanced Virgo and KAGRA gravitational-wave detectors over the next several years, with the intention of providing information to facilitate planning for multi-messenger astronomy with gravitational waves. We estimate the sensitivity of the network to transient gravitational-wave signals for the third (O3), fourth (O4) and fifth observing (O5) runs, including the planned upgrades of the Advanced LIGO and Advanced Virgo detectors. We study the capability of the network to determine the sky location of the source for gravitational-wave signals from the inspiral of binary systems of compact objects, that is binary neutron star, neutron star-black hole, and binary black hole systems. The ability to localize the sources is given as a sky-area probability, luminosity distance, and comoving volume. The median sky localization area (90% credible region) is expected to be a few hundreds of square degrees for all types of binary systems during O3 with the Advanced LIGO and Virgo (HLV) network. The median sky localization area will improve to a few tens of square degrees during O4 with the Advanced LIGO, Virgo, and KAGRA (HLVK) network. During O3, the median localization volume (90% credible region) is expected to be on the order of 10 5 , 10 6 , 10 7 Mpc 3 for binary neutron star, neutron star-black hole, and binary black hole systems, respectively. The localization volume in O4 is expected to be about a factor two smaller than in O3. We predict a detection count of 1 - 1 + 12 ( 10 - 10 + 52 ) for binary neutron star mergers, of 0 - 0 + 19 ( 1 - 1 + 91 ) for neutron star-black hole mergers, and 17 - 11 + 22 ( 79 - 44 + 89 ) for binary black hole mergers in a one-calendar-year observing run of the HLV network during O3 (HLVK network during O4). We evaluate sensitivity and localization expectations for unmodeled signal searches, including the search for intermediate mass black hole binary mergers.

3D Bioprinting in Plant Science: An Interdisciplinary Approach

Here we highlight advances and opportunities for using 3D bioprinting in plant biology research that could lead to low-cost solutions for biomedical and other applications. For example, the development of plant cell-based and plant-inspired 3D-printed constructs could provide information about single-cell, tissue, and whole-plant interactions with the surrounding environment.

Search for Subsolar Mass Ultracompact Binaries in Advanced LIGO's Second Observing Run

We present a search for subsolar mass ultracompact objects in data obtained during Advanced LIGO's second observing run. In contrast to a previous search of Advanced LIGO data from the first observing run, this search includes the effects of component spin on the gravitational waveform. We identify no viable gravitational-wave candidates consistent with subsolar mass ultracompact binaries with at least one component between 0.2  M_{⊙}-1.0  M_{⊙}. We use the null result to constrain the binary merger rate of (0.2  M_{⊙}, 0.2  M_{⊙}) binaries to be less than 3.7×10^{5}  Gpc^{-3} yr^{-1} and the binary merger rate of (1.0  M_{⊙}, 1.0  M_{⊙}) binaries to be less than 5.2×10^{3}  Gpc^{-3} yr^{-1}. Subsolar mass ultracompact objects are not expected to form via known stellar evolution channels, though it has been suggested that primordial density fluctuations or particle dark matter with cooling mechanisms and/or nuclear interactions could form black holes with subsolar masses. Assuming a particular primordial black hole (PBH) formation model, we constrain a population of merging 0.2  M_{⊙} black holes to account for less than 16% of the dark matter density and a population of merging 1.0  M_{⊙} black holes to account for less than 2% of the dark matter density. We discuss how constraints on the merger rate and dark matter fraction may be extended to arbitrary black hole population models that predict subsolar mass binaries.

P2272Determinants of left ventricular ATP availability measured in vivo and ex vivo in patients with severe aortic stenosis: correlation of creatine kinase activity with LVEF and ATP diffusion distance

Introduction

The transition to systolic failure in severe aortic stenosis (AS) increases mortality. There are currently no reliable markers of transition, and the guideline LVEF <50% threshold for intervention in asymptomatic severe AS does not capture all subjects at increased risk. In animal models, reduced ATP delivery capacity through creatine kinase (CK) is important, with modest increases in CK capacity conferring cardioprotection. ATP may also diffuse (independent of CK) from mitochondria to the contractile site. We have performed the first human study to test whether ATP diffusion distance relates to CK activity and whether CK activity is reduced in low LVEF severe AS.

Methods

19 patients with severe AS, LVEF ≥55% (AS-pEF, mean±SD LVEF 63±5%, mean gradient 48±14 mmHg) and 10 with severe AS, LVEF <55% (AS-rEF, LVEF 42±8%, mean gradient 32±11) underwent 31P-MRS for CK rate constant (kf) and phosphocreatine/ATP (PCr/ATP) ratio, and MRI for LV volumes. LV biopsies were taken during AVR and analysed for CK total activity, CK isoforms, total creatine, and citrate synthase (CS) activity. 9 biopsies also underwent serial block face scanning electron microscopy and mitochondria-sarcomere 3D distance distributions were plotted. Results were compared to 24 controls (LVEF 61±4%), of which 4 had LV biopsy (3 severe MS, 1 LA myxoma, MS-pEF). Surgical patients had flow-limiting atheroma excluded with invasive angiography and prior myocardial infarction excluded with late gadolinium enhancement MRI.

Results

When compared to controls, both CK total activity and CS activity were lower in AS-pEF (by 27% and 23% respectively, both p<0.05, Panels A-B). Although PCr/ATP reduced in AS-pEF (by 20%, p<0.001, panel C), kf (panel D) and CK flux estimated by kf × total creatine were not different. CK-MB expression reduced in AS-pEF (19 vs 27% of total CK, p=0.003), reflecting compensatory increases in CK-MM (p=0.26) and CK-BB (p=0.18) in the face of reduced CK activity.

AS-rEF was associated with further reduction in both CK and CS activities (by 32% and 22% respectively, both p<0.05, Panels A-B), but no differences in PCr/ATP, CK kf or relative CK isozyme expression were seen. There were no significant between-group differences in total creatine (Panel E). Overall this suggests that CK reserve and oxidative capacity potentially reduce in pressure overload, with further falls commensurate with systolic dysfunction.

When median mitochondria-sarcomere ATP diffusion distances were plotted against CK total activity a strong positive correlation was observed (r=0.86, p=0.003, Panel F). This suggests a compensatory reduction in diffusion distance develops when CK activity falls.

Conclusions

Transition to failure in severe AS is associated with lower oxidative capacity and maximal ATP delivery capacity through CK. Despite compensatory falls in ATP diffusion distance and altered CK isozyme expression, these changes may underlie susceptibility to EF decline in AS.

Acknowledgement/Funding

British Heart Foundation Clinical Research Training Fellowship (FS/15/80/31803) and Programme Grant (RG/18/12/34040).

P1611Non-invasive predictors of LV biopsy-obtained creatine kinase activity in patients with non-failing and failing myocardial hypertrophy

Introduction

Myocardial creatine kinase (CK) activity represents an important metabolic reserve: it correlates closely with contractile reserve and post-ischaemic function, keeps cytosolic [ADP] low, and optimises the free energy for ATP hydrolysis. It may also contribute to the transition to failure in the heart hypertrophied by chronic haemodynamic overload; modest up-regulation has been shown to be cardio-protective.

Total CK activity measurement requires chemical freeze-and-extract methods, which destroy tissue, precluding repeated measures. To date, non-invasive assessments of human myocardial CK flux (calculated as kf × [PCr], where kf is the pseudo-first-order forward rate constant measured by 31P-magnetic resonance spectroscopy (MRS) have not assessed creatine content or total CK activity. Thus we aimed to validate kf measurement against total CK activity and investigate predictors of CK activity.

Methods

39 subjects (median age 71, range 43–84) undergoing clinically indicated cardiac surgery had CK total activity measured from LV biopsy. 31 had severe AS (10 with impaired LVEF); 2 had severe primary MR; 5 had severe mitral stenosis (2 with impaired LVEF) and 1 had an LA mass. 35 of 39 contributed triplicate datasets: CK total activity, kf (31P-MRS TRiST sequence at 3T) and LV volumes (cine-MRI, 3T Siemens). 27 had severe AS (8 with impaired LVEF); other groups were the same. Exclusion criteria were prior myocardial infarction and flow-limiting coronary disease. Flash-frozen LV biopsies obtained within 15 min of cardiopulmonary bypass were analysed for CK total activity, total creatine, and citrate synthase (CS) activity (a marker of oxidative phosphorylation capacity).

Results

Multiple, novel correlations were observed between CK total activity (IU/mg protein) and CS activity (r=0.87, p=9e-13), total creatine (r=0.59, p=8e-5), kf (r=0.42, p=0.013), total creatine × kf (r=0.64, p=4e-5), LVESVi (r=−0.52, p=8e-4), LVEF (r=0.48, p=0.002) and LVMi (r=−0.42, p=0.009) (Panels A-E) (LVEDVi and non-indexed counterparts were also significant correlates.) The most predictive linear regression model incorporating elements of the CK rate equation included total creatine (nmol/mg protein), kf (/s), and kf × LVESVi (ml/m2) (adjusted R2=0.56, beta=0.426, 0.618, −1.968 and p=0.001, 5e-5, 0.003 respectively, Panel F).

Figure 1

Conclusions

These results are the first evidence of agreement between non-invasive estimates of human cardiac CK activity (kf) and freeze-extracted chemical methods. The key original finding is that it is feasible to attempt to predict CK capacity in vivo by using a combination of techniques (creatine by 1H MRS, CK kf by 31P-MRS and LVESVi by cine imaging). The key insight is that CK capacity is best estimated not simply from what the rate equation would predict (creatine and kf), but that other factors relating to failing contractility reduce CK activity independently from creatine content and enzyme kf.

Acknowledgement/Funding

British Heart Foundation Clinical Research Training Fellowship (FS/15/80/31803) and Programme Grant (RG/18/12/34040).

Unusual behavior of MgFe2O4 during regeneration: desorption versus specific adsorption

The reusability of spent adsorbents is the most important characteristic for their practical application. The process of MgFe₂O₄ regeneration after methylene blue (MB) adsorption was studied. The effect of the nature (HCl, HNO_3, and MgCl₂) and the concentration (10^-3-10^-1 M) of regeneration agents was established. All the regeneration agents at 10^-3 and 10^-2 M had high efficiency and adsorption capacity recovery reached 80-90%, whereas for 10^-1 M concentration the adsorption efficiency was in the range of 4.5-36.2%. It was shown that the concentration of desorbed MB was much less than what had been previously adsorbed and did not correlate with regeneration efficiency. The unusual behavior of MgFe₂O₄ during regeneration could be due to different mechanisms of regeneration by OH₃ ⁺ and Mg²⁺ ions: (i) for acidic regeneration the main process was the non-specific adsorption of OH₃ ⁺ ions in a diffusion layer and the substitution of adsorbed MB due to electrostatic forces; (ii) in the case of Mg²⁺ as a regeneration agent, there was specific adsorption due to the completion of a crystal lattice of MgFe₂O₄ nanoparticles by Mg²⁺ ions (according to the rules of Fayans-Pannet) with the formation of new Mg-OH adsorption sites and the super-equivalent adsorption of Mg²⁺ ions (according to DLVO (Derjaguin, Landau, Verwey, and Overbeek) theory) accompanied by a recharge of the MgFe₂O₄ surface. These phenomena of MgFe₂O₄ regeneration using Mg²⁺ ions must be taken into account in the theory and practice of adsorption.