Mesenchymal Stromal Cell Therapy for the Treatment of Intestinal Ischemia: Defining the Optimal Cell Isolate for Maximum Therapeutic Benefit

Intestinal ischemia is a devastating intraabdominal emergency that often necessitates surgical intervention. Mortality rates can be high, and patients who survive often have significant long-term morbidity. The implementation of traditional medical therapies to prevent or treat intestinal ischemia have been sparse over the last decade, and therefore, the use of novel therapies are becoming more prevalent. Cellular therapy using mesenchymal stromal cells is one such treatment modality that is attracting noteworthy attention in the scientific community. Several groups have seen benefit with cellular therapy, but the optimal cell line has not been identified. The purpose of this review is to: 1) Review the mechanism of intestinal ischemia and reperfusion injury, 2) Identify the mechanisms of how cellular therapy may be therapeutic for this disease, and 3) Compare various MSC tissue sources to maximize potential therapeutic efficacy in the treatment of intestinal I/R diseases

Certain Canine Weakly β-Hemolytic Intestinal Spirochetes Are Phenotypically and Genotypically Related to Spirochetes Associated with Human and Porcine Intestinal Spirochetosis

Four canine weakly β-hemolytic intestinal spirochetes associated with intestinal spirochetosis (IS-associated WBHIS) were compared with IS-associated human and porcine WBHIS and the type species for Serpulina hyodysenteriae and S. innocens by using phenotypic and genotypic parameters. The IS-associated canine, human, and porcine WBHIS belonged to a phyletic group distinct from but related to previously described Serpulina type species

A synthetic porcine reproductive and respiratory syndrome unprecedented levels of heterologous protection

Current vaccines do not provide sufficient levels of protection against divergent porcine reproductive and respiratory syndrome virus (PRRSV) strains circulating in the field, mainly due to the substantial variation of the viral genome. We describe here a novel approach to generate a PRRSV vaccine candidate that could confer unprecedented levels of heterologous protection against divergent PRRSV isolates. Using a set of 59 non-redundant, full genome sequences of type-2 PRRSV, a consensus genome (designated as PRRSV-CON) was these 59 PRRSV full genome sequences, followed by selecting the most common nucleotide found at each position of the alignment. Next, the synthetic PRRSV-CON virus was generated through the use of reverse genetics. The PRRSV-CON virus replicates as efficiently as our prototype PRRSV strain FL12, both in vitro and in vivo. Importantly, when inoculated in pigs, the PRRSV-CON virus confers significantly broader levels of heterologous protection than the wild-type PRRSV. Collectively, our data demonstrates that the PRRSV-CON virus can serve as an excellent candidate for the development of a broadly protective PRRS vaccine. generated by alignin

Dissipative electro-elastic network model of protein electrostatics

We propose a dissipative electro-elastic network model (DENM) to describe the dynamics and statistics of electrostatic fluctuations at active sites of proteins. The model combines the harmonic network of residue beads with overdamped dynamics of the normal modes of the network characterized by two friction coefficients. The electrostatic component is introduced to the model through atomic charges of the protein force field. The overall effect of the electrostatic fluctuations of the network is recorded through the frequency-dependent response functions of the electrostatic potential and electric field at the active site. We also consider the dynamics of displacements of individual residues in the network and the dynamics of distances between pairs of residues. The model is tested against loss spectra of residue displacements and the electrostatic potential and electric field at the heme's iron from all-atom molecular dynamics simulations of three hydrated globular proteins

Human Adipose Stromal Cells Increase Survival and Mesenteric Perfusion Following Intestinal Ischemia and Reperfusion Injury

OBJECTIVE: Intestinal ischemia can quickly escalate to bowel necrosis and perforation. Transplantation of stem cells presents a novel treatment modality for this problem. We hypothesized that: human adipose-derived stromal cells (hASCs) would increase survival and mesenteric perfusion to a greater degree compared with differentiated cellular controls following ischemic intestinal injury, and improved outcomes with hASC therapy would be associated with preservation of intestinal histological and tight junction architecture, and lower levels of systemic inflammation following intestinal injury. METHODS: hASCs and keratinocytes (differentiated cellular control) were cultured on polystyrene flasks at 37°C in 5% CO2 in air. Adult male C57Bl6J mice were anesthetized and a midline laparotomy performed. The intestines were eviscerated, the small bowel mesenteric root identified, and intestinal ischemia was established by temporarily occluding the superior mesenteric artery for 60 min with a noncrushing vascular clamp. Following ischemia, the clamp was removed, and the intestines were returned to the abdominal cavity. Before abdominal closure, 2 million hASCs or keratinocytes in 250 μL of phosphate-buffered saline (carrier for cells and control solution) were infused into the peritoneum. Animals were allowed to recover for 12 or 24 h (perfusion, histology, cytokine, and immunofluoresence studies), or 7 days (survival studies). Intestinal perfusion was assessed by laser Doppler imaging. Intestinal tissue segments were stained with hematoxylin and eosin, as well as antibodies for the tight junction protein claudin-1. Separate aliquots of intestine, liver, and lung tissue were homogenized and assessed for inflammatory cytokines via multiplex beaded assay. RESULTS: Animals administered hASCs following intestinal ischemia and reperfusion (I/R) injury had significantly greater 7-day survival and better postischemic recovery of mesenteric perfusion compared with vehicle or keratinocyte therapy. hASCs also abated intestinal mucosal destruction, facilitated preservation of intestinal tight junctions, and decreased the systemic inflammatory response to injury. CONCLUSIONS: Human adipose-derived stromal cells improved survival and mesenteric perfusion and attenuated the mucosal damage associated with intestinal I/R injury. hASCs should be considered as a plausible cell source for novel cellular treatment plans following intestinal ischemia

Trapping and hysteresis in two-phase flow in porous media: A pore-network study

Abstract: Several models for two-phase flow in porous media identify trapping and connectivity of fluids as an important contribution to macroscale hysteresis. This is especially true for hysteresis in relative permeabilities. The trapping models propose trajectories from the initial saturation to the end saturation in various ways and are often based on experiments or pore-network model results for the endpoints. However, experimental data or pore-scale model results are often not available for the trajectories, that is, the fate of the connectivity of the fluids while saturation changes. Here, using a quasi static pore-network model, supported by a set of pore-scale laboratory experiments, we study how the topology of the fluids changes during drainage and imbibition including first, main and scanning curves. We find a strong hysteretic behavior in the relationship between disconnected nonwetting fluid saturation and the wetting fluid saturation in a water-wet medium. The coalescence of the invading nonwetting phase with the existing disconnected nonwetting phase depends critically on the presence (or lack thereof) of connected nonwetting phase at the beginning of the drainage process as well as on the pore geometry. This dependence involves a mechanism we refer to as reversible corner filling. This mechanism can also be seen in laboratory experiments in volcanic tuff. The impact of these pore-network model results on existing macroscopic models is discussed.Keywords: hysteresis, trapping, two-phase flow, fluid topology, pore geometry, pore networ

Evidence of coexistence of change of caged dynamics at Tg and the dynamic transition at Td in solvated proteins

Mossbauer spectroscopy and neutron scattering measurements on proteins embedded in solvents including water and aqueous mixtures have emphasized the observation of the distinctive temperature dependence of the atomic mean square displacements, , commonly referred to as the dynamic transition at some temperature Td. At low temperatures, increases slowly, but it assume stronger temperature dependence after crossing Td, which depends on the time/frequency resolution of the spectrometer. Various authors have made connection of the dynamics of solvated proteins including the dynamic transition to that of glass-forming substances. Notwithstanding, no connection is made to the similar change of temperature dependence of obtained by quasielastic neutron scattering when crossing the glass transition temperature Tg, generally observed in inorganic, organic and polymeric glass-formers. Evidences are presented to show that such change of the temperature dependence of from neutron scattering at Tg is present in hydrated or solvated proteins, as well as in the solvents used unsurprisingly since the latter is just another organic glass-formers. The obtained by neutron scattering at not so low temperatures has contributions from the dissipation of molecules while caged by the anharmonic intermolecular potential at times before dissolution of cages by the onset of the Johari-Goldstein beta-relaxation. The universal change of at Tg of glass-formers had been rationalized by sensitivity to change in volume and entropy of the beta-relaxation, which is passed onto the dissipation of the caged molecules and its contribution to . The same rationalization applies to hydrated and solvated proteins for the observed change of at Tg.Comment: 28 pages, 10 figures, 1 Tabl

Evaluating the effects of antimicrobial drug use on the ecology of antimicrobial resistance and microbial community structure in beef feedlot cattle

IntroductionUse of antimicrobial drugs (AMDs) in food producing animals has received increasing scrutiny because of concerns about antimicrobial resistance (AMR) that might affect consumers. Previously, investigations regarding AMR have focused largely on phenotypes of selected pathogens and indicator bacteria, such as Salmonella enterica or Escherichia coli. However, genes conferring AMR are known to be distributed and shared throughout microbial communities. The objectives of this study were to employ target-enriched metagenomic sequencing and 16S rRNA gene amplicon sequencing to investigate the effects of AMD use, in the context of other management and environmental factors, on the resistome and microbiome in beef feedlot cattle.MethodsThis study leveraged samples collected during a previous longitudinal study of cattle at beef feedlots in Canada. This included fecal samples collected from randomly selected individual cattle, as well as composite-fecal samples from randomly selected pens of cattle. All AMD use was recorded and characterized across different drug classes using animal defined daily dose (ADD) metrics.ResultsOverall, fecal resistome composition was dominated by genes conferring resistance to tetracycline and macrolide-lincosamide-streptogramin (MLS) drug classes. The diversity of bacterial phyla was greater early in the feeding period and decreased over time in the feedlot. This decrease in diversity occurred concurrently as the microbiome represented in different individuals and different pens shifted toward a similar composition dominated by Proteobacteria and Firmicutes. Some antimicrobial drug exposures in individuals and groups were associated with explaining a statistically significant proportion of the variance in the resistome, but the amount of variance explained by these important factors was very small (<0.6% variance each), and smaller than associations with other factors measured in this study such as time and feedlot ID. Time in the feedlot was associated with greater changes in the resistome for both individual animals and composite pen-floor samples, although the proportion of the variance associated with this factor was small (2.4% and 1.2%, respectively).DiscussionResults of this study are consistent with other investigations showing that, compared to other factors, AMD exposures did not have strong effects on antimicrobial resistance or the fecal microbial ecology of beef cattle

Traveling Wave Solutions in a Generalized Theory for Macroscopic Capillarity

One-dimensional traveling wave solutions for imbibition processes into a homogeneous porous medium are found within a recent generalized theory of macroscopic capillarity. The generalized theory is based on the hydrodynamic differences between percolating and nonpercolating fluid parts. The traveling wave solutions are obtained using a dynamical systems approach. An exhaustive study of all smooth traveling wave solutions for primary and secondary imbibition processes is reported here. It is made possible by introducing two novel methods of reduced graphical representation. In the first method the integration constant of the dynamical system is related graphically to the boundary data and the wave velocity. In the second representation the wave velocity is plotted as a function of the boundary data. Each of these two graphical representations provides an exhaustive overview over all one-dimensional and smooth solutions of traveling wave type, that can arise in primary and secondary imbibition. Analogous representations are possible for other systems, solution classes, and processes.</p