SARS-CoV-2 NSP14 governs mutational instability and assists in making new SARS-CoV-2 variants.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the rapidly evolving RNA virus behind the COVID-19 pandemic, has spawned numerous variants since its 2019 emergence. The multifunctional Nonstructural protein 14 (NSP14) enzyme, possessing exonuclease and messenger RNA (mRNA) capping capabilities, serves as a key player. Notably, single and co-occurring mutations within NSP14 significantly influence replication fidelity and drive variant diversification.

Hippocampal Microglia Activation Induced by Acute Pancreatic Injury in Rats.

Background: Acute pancreatitis is an inflammation of the pancreatic glandular parenchyma that causes injury with or without the destruction of pancreatic acini. Clinical and experimental evidence suggest that certain systemic proinflammatory mediators may be responsible for initiating the fundamental mechanisms involved in microglial reactivity. Here, we investigated the possible repercussions of acute pancreatitis (AP) on the production of inflammatory mediators in the brain parenchyma focusing on microglial activation in the hippocampus.

Ultrasound biomicroscopy in the quantification of brain perfusion parameters of a rat stroke model: Analysis of contrast agent bolus kinetic dynamics.

Background: Ischemic stroke represents a significant global health concern, necessitating thorough investigations and the utilization of stroke animal models to explore novel treatment modalities and diagnostic imaging techniques.

New Method: Ultrasound biomicroscopy (BMU), operating at a center frequency of 21 MHz, along with ultrasound contrast agents (UCAs), was used to quantify microcirculation cerebral blood flow in a rat model of ischemic stroke. The microcirculation parameters were derived from time intensity curve (TIC) plots obtained based on UCA-bolus kinetics.

Would New SARS-CoV-2 Variants Change the War against COVID-19?

The scientific, private, and industrial sectors use a wide variety of technological platforms available to achieve protection against SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2), including vaccines. However, the virus evolves continually into new highly virulent variants, which might overcome the protection provided by vaccines and may re-expose the population to infections. Mass vaccinations should be continued in combination with more or less mandatory non-pharmaceutical interventions.

Non-uniform aspects of the SARS-CoV-2 intraspecies evolution reopen question of its origin.

Several hypotheses have been presented on the origin of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) from its identification as the agent causing the current coronavirus disease 19 (COVID-19) pandemic. So far, no solid evidence has been found to support any hypothesis on the origin of this virus, and the issue continue to resurface over and over again. Here we have unfolded a pattern of distribution of several mutations in the SARS-CoV-2 proteins in 24 geo-locations across different continents.

An issue of concern: unique truncated ORF8 protein variants of SARS-CoV-2.

Open reading frame 8 (ORF8) shows one of the highest levels of variability among accessory proteins in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of Coronavirus Disease 2019 (COVID-19). It was previously reported that the ORF8 protein inhibits the presentation of viral antigens by the major histocompatibility complex class I (MHC-I), which interacts with host factors involved in pulmonary inflammation. The ORF8 protein assists SARS-CoV-2 in evading immunity and plays a role in SARS-CoV-2 replication.

The importance of accessory protein variants in the pathogenicity of SARS-CoV-2.

The coronavirus disease 2019 (COVID-19) is caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS- CoV-2) with an estimated fatality rate of less than 1%. The SARS-CoV-2 accessory proteins ORF3a, ORF6, ORF7a, ORF7b, ORF8, and ORF10 possess putative functions to manipulate host immune mechanisms. These involve interferons, which appear as a consensus function, immune signaling receptor NLRP3 (NLR family pyrin domain-containing 3) inflammasome, and inflammatory cytokines such as interleukin 1β (IL-1β) and are critical in COVID-19 pathology.

Periodically aperiodic pattern of SARS-CoV-2 mutations underpins the uncertainty of its origin and evolution.

Various lineages of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) have contributed to prolongation of the Coronavirus Disease 2019 (COVID-19) pandemic. Several non-synonymous mutations in SARS-CoV-2 proteins have generated multiple SARS-CoV-2 variants. In our previous report, we have shown that an evenly uneven distribution of unique protein variants of SARS-CoV-2 is geo-location or demography-specific.

COVID-19 Vaccines and Thrombosis-Roadblock or Dead-End Street?

Two adenovirus-based vaccines, ChAdOx1 nCoV-19 and Ad26.COV2.S, and two mRNA-based vaccines, BNT162b2 and mRNA.

Cryopreserved Rat Thyroid Autotransplantation in the Treatment of Postoperative Hypothyroidism.

To verify the viability and functionality of cryopreserved thyroid autotransplantation in rats who underwent total thyroidectomy in the treatment of postoperative hypothyroidism. Thirty-two Wistar rats were randomly assigned into groups (G) with eight animals each: control (CG); simulation (SG); hypothyroidism (HTG) and transplanted (TG). At the beginning and in the 13th week of the experiment, serum levels of total T3, free T4, TSH and calcium were determined.

Notable sequence homology of the ORF10 protein introspects the architecture of SARS-CoV-2.

The current Coronavirus Disease 19 (COVID-19) pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) shows similar pathology to MERS and SARS-CoV, with a current estimated fatality rate of 1.4%. Open reading frame 10 (ORF10) is a unique SARS-CoV-2 accessory protein, which contains eleven cytotoxic T lymphocyte (CTL) epitopes each of nine amino acids in length.

Urgent Need for Field Surveys of Coronaviruses in Southeast Asia to Understand the SARS-CoV-2 Phylogeny and Risk Assessment for Future Outbreaks.

Phylogenetic analysis of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is focused on a single isolate of bat coronaviruses (bat CoVs) which does not adequately represent genetically related coronaviruses (CoVs) [...

Possible Transmission Flow of SARS-CoV-2 Based on ACE2 Features.

Angiotensin-converting enzyme 2 (ACE2) is the cellular receptor for the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) that is engendering the severe coronavirus disease 2019 (COVID-19) pandemic. The spike (S) protein receptor-binding domain (RBD) of SARS-CoV-2 binds to the three sub-domains viz. amino acids (aa) 22-42, aa 79-84, and aa 330-393 of ACE2 on human cells to initiate entry.

The structural basis of accelerated host cell entry by SARS-CoV-2†.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the pandemic coronavirus disease 2019 (COVID-19) that exhibits an overwhelming contagious capacity over other human coronaviruses (HCoVs). This structural snapshot describes the structural bases underlying the pandemic capacity of SARS-CoV-2 and explains its fast motion over respiratory epithelia that allow its rapid cellular entry. Based on notable viral spike (S) protein features, we propose that the flat sialic acid-binding domain at the N-terminal domain (NTD) of the S1 subunit leads to more effective first contact and interaction with the sialic acid layer over the epithelium, and this, in turn, allows faster viral 'surfing' of the epithelium and receptor scanning by SARS-CoV-2.

Protective effect of adipose tissue-derived mesenchymal stromal cells in an experimental model of high-risk colonic anastomosis.

Background: Dehiscence of intestinal anastomosis results in high morbidity and mortality. The aim of this study was to investigate the effects of locally administered adipose tissue-derived mesenchymal stromal cells in a model of high-risk colonic anastomosis in rats.

Methods: Seven days after induction of colitis with 2,4,6-trinitrobenzene sulfonic acid, Wistar rats were submitted to a transection of the descending colon followed by end-to-end anastomosis and were then treated with 2×10 adipose tissue-derived mesenchymal stromal cells (from the preperitoneal fat) or an acellular culture solution instilled onto the surface of the anastomosis.

Rat models of high risk colorectal anastomoses 1.

Purpose: To evaluate the most frequent surgical techniques of high-risk colorectal anastomoses in rats.

Methods: Wistar rats were enrolled in three different models comprising inflammatory (TNBS enema), vascular (portal vein occlusion) or obstructive (a non-ischemic constricting ring) mechanisms associated with colonic anastomosis that had accomplished after these former lesions. Histological analyses (Hematoxylin and eosin and Picrosirius red) were performed.

Cholecystectomy during ceftriaxone therapy. A translational study with a new rabbit model.

Purpose: To evaluate the actual incidence of both microlithiasis and acute cholecystitis during treatment with intravenous ceftriaxone in a new rabbit model.

Methods: New Zealand rabbits were treated with intravenous ceftriaxone or saline for 21 days. Ultrasound monitoring of the gallbladder was performed every seven days until the 21st day when histopathology, immunohistochemistry for proliferating cell nuclear antigen (PCNA), pro-caspase-3 and CD68, liver enzyme biochemistry, and chromatography analysis of the bile and sediments were also performed.

Streptococcus pneumoniae resists intracellular killing by olfactory ensheathing cells but not by microglia.

Olfactory ensheathing cells (OECs) are a type of specialized glial cell currently considered as having a double function in the nervous system: one regenerative, and another immune. Streptococcus pneumoniae is a major agent of severe infections in humans, including meningitis. It is commonly found in the nasopharynx of asymptomatic carriers, and, under certain still unknown conditions, can invade the brain.

Exogenous pulmonary surfactant prevents the development of intra-abdominal adhesions in rats.

Intra-abdominal adhesions are major post-operative complications for which no effective means of prevention is available. We aimed to evaluate the efficacy of exogenous pulmonary surfactant administration in the prevention of post-operative abdominal adhesions. Rats were randomly assigned to undergo laparotomy (L) or gastroenterostomy (GE) and then treated with surfactant (groups L-S and GE-S, respectively).

Evidence of involvement of the mannose receptor in the internalization of Streptococcus pneumoniae by Schwann cells.

Background: The ability of S. pneumoniae to generate infections depends on the restrictions imposed by the host's immunity, in order to prevent the bacterium from spreading from the nasopharynx to other tissues, such as the brain. Some authors claim that strains of S.

Ischemia-reperfusion rat model of acute pancreatitis: protein carbonyl as a putative early biomarker of pancreatic injury.

Acute pancreatitis (AP) is an inflammatory disorder that can affect adjacent and/or remote organs. Some evidence indicates that the production of reactive oxygen species is able to induce AP. Protein carbonyl (PC) derivatives, which can also be generated through oxidative cleavage mechanisms, have been implicated in several diseases, but there is little or no information on this biomarker in AP.

The mannose receptor is expressed by olfactory ensheathing cells in the rat olfactory bulb.

Complex carbohydrate structures are essential molecules of infectious bacteria, parasites, and host cells and are involved in cell signaling associated with immune responses, glycoprotein homeostasis, and cell migration. The uptake of mannose-tailed glycans is usually carried out by professional phagocytes to trigger MHC class I- and MHC class II-restricted antigen presentation or, alternatively, to end inflammation. We have detected the mannose receptor (MR) in cultured olfactory ensheathing cells (OECs), so we investigated by flow cytometry whether recently dissociated cells of the olfactory bulb (OB) nerve fiber layer (ONL) could bind a mannosylated ligand (fluorescein conjugate of mannosyl bovine serum albumin; Man/BSA-FITC) in a specific manner.

Bone marrow mononuclear cells and mannose receptor expression in focal cortical ischemia.

The use of bone marrow mononuclear cells (BMMCs) has been shown as a putative efficient therapy for stroke. However, the mechanisms of therapeutic action are not yet completely known. Mannose receptor (MR) is a subgroup of the C-type lectin receptor superfamily involved in innate immune response in several tissues.