A statistical analysis of murine incisional and excisional acute wound models

YesMice represent the most commonly used species for preclinical in vivo research. While incisional and excisional acute murine wound models are both frequently employed, there is little agreement on which model is optimum. Moreover, current lack of standardization of wounding procedure, analysis time point(s), method of assessment, and the use of individual wounds vs. individual animals as replicates makes it difficult to compare across studies. Here we have profiled secondary intention healing of incisional and excisional wounds within the same animal, assessing multiple parameters to determine the optimal methodology for future studies. We report that histology provides the least variable assessment of healing. Furthermore, histology alone (not planimetry) is able to detect accelerated healing in a castrated mouse model. Perhaps most importantly, we find virtually no correlation between wounds within the same animal, suggesting that use of wound (not animal) biological replicates is perfectly acceptable. Overall, these findings should guide and refine future studies, increasing the likelihood of detecting novel phenotypes while reducing the numbers of animals required for experimentation

Evaluating STZ-Induced Impaired Wound Healing in Rats

YesMedical Research Council, Innovate UK and Epistem Ltd

A multiphase seismic investigation of the shallow subduction zone, southern North Island, New Zealand

The shallow structure of the Hikurangi margin, in particular the interface between the Australian Plate and the subducting Pacific Plate, is investigated using the traveltimes of direct and converted seismic phases from local earthquakes. Mode conversions take place as upgoing energy from earthquakes in the subducted slab crosses the plate interface. These PS and SP converted arrivals are observed as intermediate phases between the direct P and S waves. They place an additional constraint on the depth of the interface and enable the topography of the subducted plate to be mapped across the region. 301 suitable earthquakes were recorded by the Leeds (Tararua) broad-band seismic array, a temporary line of three-component short-period stations, and the permanent stations of the New Zealand national network. This provided coverage across the land area of southern North Island, New Zealand, at a total of 17 stations. Rays are traced through a structure parametrized using layered B-splines and the traveltime residuals inverted, simultaneously, for hypocentre relocation, interface depth and seismic velocity. The results are consistent with sediment in the northeast of the study region and gentle topography on the subducting plate. This study and recent tectonic reconstructions of the southwest Pacific suggest that the subducting plate consists of captured, oceanic crust. The anomalous nature of this crust partly accounts for the unusual features of the Hikurangi margin, e.g. the shallow trench, in comparison with the subducting margin further north

Ppia and ywhaz constitute a stable pair of reference genes during electrical stimulation in mesenchymal stem cells

YesMesenchymal stem cells (MSCs) are multipotent adult stem cells with great potential in regenerative medicine. One method for stimulating proliferation and differentiation of MSCs is via electrical stimulation (ES). A valuable approach for evaluating the response of MSCs to ES is to assess changes in gene expression, relative to one or more reference genes. In a survey of 25 publications that used ES on cells, 70% selected GAPDH as the reference gene. We conducted a study to assess the suitability of six potential reference genes on an immortalized human MSC line following direct current ES at seeding densities of 5000 and 10,000 cells/cm2 . We employed three methods to validate the most stable reference genes from qRT-PCR data. Our findings show that GAPDH and ACTB exhibit reduced stability when seeded at 5000 cell/cm2 . In contrast, we found that the most stable genes across both plating densities and stimulation regimes were PPIA and YWHAZ. Thus, in ES gene expression studies in MSCs, we support the use of PPIA and YWHAZ as an optimal reference gene pair, and discourage the use of ACTB and GAPDH at lower seeding densities. However, it is strongly recommended that similar verification studies are carried out based on cell type and different ES conditions

Interleukin-15 Affects Patient Survival through Natural Killer Cell Recovery after Autologous Hematopoietic Stem Cell Transplantation for Non-Hodgkin Lymphomas

Natural killer cells at day 15 (NK-15), after autologous peripheral blood hematopoietic stem cell transplantation (APHSCT), is a prognostic factor for overall survival (OS) and progression-free survival (PFS) in non-Hodgkin lymphoma (NHL). The potential role of the immunologic (homeostatic) environment affecting NK-15 recovery and survival post-APHSCT has not been fully studied. Therefore, we evaluate prospectively the cytokine profile in 50 NHL patients treated with APHSCT. Patients with an interleukin-15 (IL-15) ≥ 76.5 pg/mL at day 15 post-APHSCT experienced superior OS and PFS compared with those who did not; median OS; not reached versus 19.2 months, P < .002; and median PFS; not reached versus 6.8 months, P < .002, respectively. IL-15 was found to correlate with (rs = 0.7, P < .0001) NK-15. Multivariate analysis showed only NK-15 as a prognostic factor for survival, suggesting that the survival benefit observed by IL-15 is most likely mediated by enhanced NK cell recovery post-APHSCT

Genome-wide DNA methylation analysis for diabetic nephropathy in type 1 diabetes mellitus

BACKGROUND: Diabetic nephropathy is a serious complication of diabetes mellitus and is associated with considerable morbidity and high mortality. There is increasing evidence to suggest that dysregulation of the epigenome is involved in diabetic nephropathy. We assessed whether epigenetic modification of DNA methylation is associated with diabetic nephropathy in a case-control study of 192 Irish patients with type 1 diabetes mellitus (T1D). Cases had T1D and nephropathy whereas controls had T1D but no evidence of renal disease. METHODS: We performed DNA methylation profiling in bisulphite converted DNA from cases and controls using the recently developed Illumina Infinium(R) HumanMethylation27 BeadChip, that enables the direct investigation of 27,578 individual cytosines at CpG loci throughout the genome, which are focused on the promoter regions of 14,495 genes. RESULTS: Singular Value Decomposition (SVD) analysis indicated that significant components of DNA methylation variation correlated with patient age, time to onset of diabetic nephropathy, and sex. Adjusting for confounding factors using multivariate Cox-regression analyses, and with a false discovery rate (FDR) of 0.05, we observed 19 CpG sites that demonstrated correlations with time to development of diabetic nephropathy. Of note, this included one CpG site located 18 bp upstream of the transcription start site of UNC13B, a gene in which the first intronic SNP rs13293564 has recently been reported to be associated with diabetic nephropathy. CONCLUSION: This high throughput platform was able to successfully interrogate the methylation state of individual cytosines and identified 19 prospective CpG sites associated with risk of diabetic nephropathy. These differences in DNA methylation are worthy of further follow-up in replication studies using larger cohorts of diabetic patients with and without nephropathy

Phosphine Resistance in the Rust Red Flour Beetle, Tribolium castaneum (Coleoptera: Tenebrionidae): Inheritance, Gene Interactions and Fitness Costs

The recent emergence of heritable high level resistance to phosphine in stored grain pests is a serious concern among major grain growing countries around the world. Here we describe the genetics of phosphine resistance in the rust red flour beetle Tribolium castaneum (Herbst), a pest of stored grain as well as a genetic model organism. We investigated three field collected strains of T. castaneum viz., susceptible (QTC4), weakly resistant (QTC1012) and strongly resistant (QTC931) to phosphine. The dose-mortality responses of their test- and inter-cross progeny revealed that most resistance was conferred by a single major resistance gene in the weakly (3.2×) resistant strain. This gene was also found in the strongly resistant (431×) strain, together with a second major resistance gene and additional minor factors. The second major gene by itself confers only 12–20× resistance, suggesting that a strong synergistic epistatic interaction between the genes is responsible for the high level of resistance (431×) observed in the strongly resistant strain. Phosphine resistance is not sex linked and is inherited as an incompletely recessive, autosomal trait. The analysis of the phenotypic fitness response of a population derived from a single pair inter-strain cross between the susceptible and strongly resistant strains indicated the changes in the level of response in the strong resistance phenotype; however this effect was not consistent and apparently masked by the genetic background of the weakly resistant strain. The results from this work will inform phosphine resistance management strategies and provide a basis for the identification of the resistance genes