Variable Induction of Pro-inflammatory Cytokines by Commercial SARS CoV-2 Spike Protein Reagents: Potential Impacts of LPS on In Vitro Modeling and Pathogenic Mechanisms In Vivo

Proinflammatory cytokine production following infection with severe acute respiratory syndrome coronavirus 2 (SARS CoV-2) is associated with poor clinical outcomes. Like SARS CoV-1, SARS CoV-2 enters host cells via its spike protein, which attaches to angiotensin-converting enzyme 2 (ACE2). As SARS CoV-1 spike protein is reported to induce cytokine production, we hypothesized that this pathway could be a shared mechanism underlying pathogenic immune responses. We herein compared the capabilities of Middle East Respiratory Syndrome (MERS), SARS CoV-1 and SARS CoV-2 spike proteins to induce cytokine expression in human peripheral blood mononuclear cells (PBMC). We observed that only specific commercial lots of SARS CoV-2 induce cytokine production. Surprisingly, recombinant SARS CoV-2 spike proteins from different vendors and batches exhibited different patterns of cytokine induction, and these activities were not inhibited by blockade of spike protein-ACE2 binding using either soluble ACE2 or neutralizing anti-S1 antibody. Moreover, commercial spike protein reagents contained varying levels of endotoxin, which correlated directly with their abilities to induce cytokine production. The lipopolysaccharide (LPS) inhibitor, polymyxin B, blocked this cytokine induction activity. In addition, SARS CoV-2 spike protein avidly bound soluble LPS in vitro, rendering it a cytokine inducer. These results not only suggest caution in monitoring the purity of SARS CoV-2 spike protein reagents, but they indicate the possibility that interactions of SARS CoV-2 spike protein with LPS from commensal bacteria in virally infected mucosal tissues could promote pathogenic inflammatory cytokine production.

Histologic Examination of an Assemblage of Psittacosaurus (Dinosauria: Ceratopsia) Juveniles From the Yixian Formation (Liaoning, China).

Psittacosaurus is one of the most abundant dinosaurs known, which allows for extensive study of its growth and form. Previous studies have evaluated growth trajectories of Psittacosaurus using bone histology. However, we present the first study of Psittacosaurus comparative juvenile histology and describe the histology of Psittacosaurus within its first year of life based on multiple sections taken from an exquisite monospecific assemblage of juveniles from the Yixian Formation in Liaoning, China. Specimens studied had femur lengths ranging from 30 to 36 mm. The five juveniles examined all have similar histologic patterns in the midshaft and epiphyseal regions showing that there is limited plasticity in bone development in juvenile Psittacosaurus and that all of the specimens in the assemblage were likely the same age. The microstructure patterns are compatible with the hypothesis that Psittacosaurus was precocial and that these juveniles were neonates. Based on comparisons with other juvenile ornithischians, juvenile Psittacosaurus had a growth rate similar to Orodromeus, slower than that of Maiasaura, Dysalotosaurus, or hadrosaurs consistent with small body size. Our results support previous studies that demonstrated that the orientation of vascular canals is likely not solely reflective of growth rate, but is also affected by underlying biomechanical, structural processes. The number of studies done on theropod and sauropodomorph histology dwarfs those of ornithischians. More studies of ornithischian histology are necessary in order to better establish phylogenetic trends in microstructure and to learn more about growth in this important clade.

A new specimen of the Early Cretaceous bird Hongshanornis longicresta: insights into the aerodynamics and diet of a basal ornithuromorph.

The discovery of Hongshanornis longicresta, a small ornithuromorph bird with unusually long hindlimb proportions, was followed by the discovery of two closely related species, Longicrusavis houi and Parahongshanornis chaoyangensis. Together forming the Hongshanornithidae, these species reveal important information about the early diversity and morphological specialization of ornithuromorphs, the clade that contains all living birds. Here we report on a new specimen (DNHM D2945/6) referable to Hongshanornis longicresta that contributes significant information to better understand the morphology, trophic ecology, and aerodynamics of this species, as well as the taxonomy of the Hongshanornithidae. Most notable are the well-preserved wings and feathered tail of DNHM D2945/6, which afford an accurate reconstruction of aerodynamic parameters indicating that as early as 125 million years ago, basal ornithuromorphs had evolved aerodynamic surfaces comparable in size and design to those of many modern birds, and flight modes alike to those of some small living birds.

Gender identification of the Mesozoic bird Confuciusornis sanctus.

Hundreds of specimens of the beaked bird Confuciusornis sanctus have been recovered from Early Cretaceous lake deposits of northeastern China. These birds show remarkable variation in size and plumage, with some displaying two long, central ornamental rectrices (tail feathers) and others lacking them altogether. Although, traditionally specimens with ornamental rectrices were interpreted as males and those without them as females, this supposed sexual dimorphism has remained unconfirmed. Here we report on the discovery of medullary bone, a tissue unique to reproductively active female birds, in a specimen of C. sanctus (DNHM-D1874) lacking these feathers. Our discovery constitutes the first case of gender identification in a Mesozoic bird, and it provides undisputed evidence that individuals of C. sanctus without ornamental rectrices are females. By permitting gender identification in C. sanctus, our results provide insight into the onset of sexual maturity and attainment of adult body size of this and other early birds.

Radiosensitizing effect of gemcitabine on human lung cancer cells : A preliminary in vitro study / 中华放射肿瘤学杂志

Objective To investigate whether gemcitabine (GEM) could enhance radiosensitivity of human non-small cell lung cancer cells and its related mechanism.Methods Clonogenic assay was used to analyze radiosensitivity enhancement by GEM on p53 mutant human lung adenocarcinoma cell line 973.Alterations of cell cycle distribution and apoptosis were measured by flow cytometry.Results Mild radiosesitizing effect was observed when 10 nmol/L GEM was administrated before or after irradiation.Marked radiosesitizing effect was demonstrated when 100 nmol/L GEM was administrated before or after irradiation, with much stronger effect of pre-irradiation GEM treatment.Mutation of p53 gene affected cell cycle redistribution and cell apoptosis, but had no relationship with radiosensitivity enhancement of GEM.Conclusions 100 nmol/L GEM could significantly enhance radiosensitivity of human lung cancer cells.However, this effect may not be associated with p53 gene mutation, cell cycle redistribution or cell apoptosis.

Effect of early postoperative enteral nutrition on patients after gastrectomy and nursing strategy / 中国实用护理杂志

Objective To study the effect of early postoperative enteral nutrition on patients after gastrectomy and nursing strategy. Methods Sixty patients with gastric cancer were assigned into the observation group and the control group after gastrectomy.Both groups accepted the regular nursing nutrition.The observation group also received early postoperative enteral nutritional supply 12 hours postoperation.The nutritional conditions, immune conditions, anal exsufflation and defecation and complications between two groups were recorded both preoperation and on the 8th day postoperation.χ2test and t test were used. Results On the 8th day postoperation,the observation group was better than the control group in prealbumin, serum albumin, transferrin, fibronectin and total protein,lymphocyte count, IgA, IgG and IgM.The observation group was also superior to the control group in recovery time of bowel sound, anal exsufflation and defecation, foodintake time, expense of nu-trition treatment, hospitalization time and incidence rate of complication. Conclusions The early postoperative enteral nutrition can promote nutritional condition, advance immunity, improve functional rehabilitation of gastrointestine and reduce the incidence rate of complication and hospitalization time.