Antibiotic Spacers in Shoulder Arthroplasty: Comparison of Stemmed and Stemless Implants.

Background: Antibiotic spacers in shoulder periprosthetic joint infection deliver antibiotics locally and provide temporary stability. The purpose of this study was to evaluate differences between stemmed and stemless spacers. Methods: All spacers placed from 2011 to 2013 were identified. Stemless spacers were made by creating a spherical ball of cement placed in the joint space. Stemmed spacers had some portion in the humeral canal. Operative time, complications, reimplantation, reinfection, and range of motion were analyzed. Results: There were 37 spacers placed: 22 were stemless and 15 were stemmed. The stemless spacer population was older (70.9 ± 7.8 years vs. 62.8 ± 8.4 years, p = 0.006). The groups had a similar percentage of each gender (stemless group, 45% male vs. stemmed group, 40% male; p = 0.742), body mass index (stemless group, 29.1 ± 6.4 kg/m2 vs. stemmed group, 31.5 ± 8.3 kg/m2; p = 0.354) and Charlson Comorbidity Index (stemless group, 4.2 ± 1.2 vs. stemmed group, 4.2 ± 1.7; p = 0.958). Operative time was similar (stemless group, 127.5 ± 37.1 minutes vs. stemmed group, 130.5 ± 39.4 minutes). Two stemless group patients had self-resolving radial nerve palsies. Within the stemless group, 15 of 22 (68.2%) underwent reimplantation with 14 of 15 having forward elevation of 109° ± 23°. Within the stemmed group, 12 of 15 (80.0%, p = 0.427) underwent reimplantation with 8 of 12 having forward elevation of 94° ± 43° (range, 30° to 150°; p = 0.300). Two stemmed group patients had axillary nerve palsies, one of which self-resolved but the other did not. One patient sustained dislocation of reverse shoulder arthroplasty after reimplantation. One stemless group patient required an open reduction and glenosphere exchange of dislocated reverse shoulder arthroplasty at 6 weeks after reimplantation. Conclusions: Stemmed and stemless spacers had similar clinical outcomes. When analyzing all antibiotic spacers, over 70% were converted to revision arthroplasties. The results of this study do not suggest superiority of either stemmed or stemless antibiotic spacers

What Are the Factors that Influence Caregiver/Parent Co-sleeping Education?

poster abstractBackground: In the United States, 13% of infants routinely co-sleep with a caregiver, and 50% of infants share a bed with a caregiver for part of the night. Co-sleeping has been identified as a risk factor for infant death by Sudden Unexplained Infant Death Syndrome (SUIDS). The purpose of this research was to carry out a systematic review for determining best practices related to education to caregivers on the risks of co-sleeping. Method: After a rigorous multi-database search, we accessed 100 research articles related to SUIDS from years 2002-2015 for inclusion for this review. A total of 20 papers related to co-sleeping and SUIDS met the inclusion criteria and were assessed for validity by a primary and secondary reviewer via standardized critical appraisal instruments from the Joanna Briggs Institute. Due to the articles’ descriptive methods, NOTARI (Narrative, Opinion, and Text Assessment and Review Instrument) was used to appraise, extract data, and thematically organize the findings resulting in meta-aggregation. Results: The data extracted included specific details for co-sleeping. We identified that a) educational, b) family dynamics, c) racial/cultural, and d) socioeconomic factors were the significant concepts that influenced the caregivers’ attitude toward co-sleeping and their likelihood to co-sleep. Heterogeneity for the study’s methods was represented in the results. Conclusions: Many caregivers and families that practice co-sleeping display resistance to education about the discontinuation of co-sleeping based on the belief that healthcare providers do not take into account the family’s personal situation. The caregivers are more likely to be receptive to advice regarding safer co-sleeping practices as opposed to omitting the practice of co-sleeping. Family-centered interventions and tailored education delivered by nurses should be identified. Caregiver safe practices for sleep, taking into account situational factors such as socioeconomic level, race, culture, and core beliefs, should be encouraged

In Vitro Selection of a Single-Stranded DNA Molecular Recognition Element against Atrazine

Widespread use of the chlorotriazine herbicide, atrazine, has led to serious environmental and human health consequences. Current methods of detecting atrazine contamination are neither rapid nor cost-effective. In this work, atrazine-specific single-stranded DNA (ssDNA) molecular recognition elements (MRE) were isolated. We utilized a stringent Systematic Evolution of Ligands by Exponential Enrichment (SELEX) methodology that placed the greatest emphasis on what the MRE should not bind to. After twelve rounds of SELEX, an atrazine-specific MRE with high affinity was obtained. The equilibrium dissociation constant (Kd) of the ssDNA sequence is 0.62 ± 0.21 nM. It also has significant selectivity for atrazine over atrazine metabolites and other pesticides found in environmentally similar locations and concentrations. Furthermore, we have detected environmentally relevant atrazine concentrations in river water using this MRE. The strong affinity and selectivity of the selected atrazine-specific ssDNA validated the stringent SELEX methodology and identified a MRE that will be useful for rapid atrazine detection in environmental sample

Distribution of guanylate cyclase within photoreceptor outer segments

Guanylate cyclases play an essential role in the recovery of vertebrate photoreceptor cells after light activation. Here, we have investigated how one such guanylate cyclase, RetGC-1, is distributed within light- and dark-adapted rod photoreceptor cells. Guanylate cyclase activity partitioned with the photoreceptor outer segment (OS) cytoskeleton in a light-sensitive manner. RetGC-1 was found to bind actin filaments in actin blot overlays, suggesting a mechanism for its association with the OS cytoskeleton. In retinal sections, this enzyme was immunodetected only in the OSs, where it appeared to be distributed throughout the disk membranes

Microbiome succession during ammonification in eelgrass bed sediments

Background Eelgrass (Zostera marina) is a marine angiosperm and foundation species that plays an important ecological role in primary production, food web support, and elemental cycling in coastal ecosystems. As with other plants, the microbial communities living in, on, and near eelgrass are thought to be intimately connected to the ecology and biology of eelgrass. Here we characterized the microbial communities in eelgrass sediments throughout an experiment to quantify the rate of ammonification, the first step in early remineralization of organic matter, also known as diagenesis, from plots at a field site in Bodega Bay, CA. Methods Sediment was collected from 72 plots from a 15 month long field experiment in which eelgrass genotypic richness and relatedness were manipulated. In the laboratory, we placed sediment samples (n = 4 per plot) under a N2 atmosphere, incubated them at in situ temperatures (15 °C) and sampled them initially and after 4, 7, 13, and 19 days to determine the ammonification rate. Comparative microbiome analysis using high throughput sequencing of 16S rRNA genes was performed on sediment samples taken initially and at seven, 13 and 19 days to characterize changes in the relative abundances of microbial taxa throughout ammonification. Results Within-sample diversity of the sediment microbial communities across all plots decreased after the initial timepoint using both richness based (observed number of OTUs, Chao1) and richness and evenness based diversity metrics (Shannon, Inverse Simpson). Additionally, microbial community composition changed across the different timepoints. Many of the observed changes in relative abundance of taxonomic groups between timepoints appeared driven by sulfur cycling with observed decreases in predicted sulfur reducers (Desulfobacterales) and corresponding increases in predicted sulfide oxidizers (Thiotrichales). None of these changes in composition or richness were associated with variation in ammonification rates. Discussion Our results showed that the microbiome of sediment from different plots followed similar successional patterns, which we infer to be due to changes related to sulfur metabolism. These large changes likely overwhelmed any potential changes in sediment microbiome related to ammonification rate. We found no relationship between eelgrass presence or genetic composition and the microbiome. This was likely due to our sampling of bulk sediments to measure ammonification rates rather than sampling microbes in sediment directly in contact with the plants and suggests that eelgrass influence on the sediment microbiome may be limited in spatial extent. More in-depth functional studies associated with eelgrass microbiome will be required in order to fully understand the implications of these microbial communities in broader host-plant and ecosystem functions (e.g., elemental cycling and eelgrass-microbe interactions)

Lrp5 and Lrp6 exert overlapping functions in osteoblasts during postnatal bone acquisition

The canonical Wnt signaling pathway is critical for skeletal development and maintenance, but the precise roles of the individual Wnt co-receptors, Lrp5 and Lrp6, that enable Wnt signals to be transmitted in osteoblasts remain controversial. In these studies, we used Cre-loxP recombination, in which Cre-expression is driven by the human osteocalcin promoter, to determine the individual contributions of Lrp5 and Lrp6 in postnatal bone acquisition and osteoblast function. Mice selectively lacking either Lrp5 or Lrp6 in mature osteoblasts were born at the expected Mendelian frequency but demonstrated significant reductions in whole-body bone mineral density. Bone architecture measured by microCT revealed that Lrp6 mutant mice failed to accumulate normal amounts of trabecular bone. By contrast, Lrp5 mutants had normal trabecular bone volume at 8 weeks of age, but with age, these mice also exhibited trabecular bone loss. Both mutants also exhibited significant alterations in cortical bone structure. In vitro differentiation was impaired in both Lrp5 and Lrp6 null osteoblasts as indexed by alkaline phosphatase and Alizarin red staining, but the defect was more pronounced in Lrp6 mutant cells. Mice lacking both Wnt co-receptors developed severe osteopenia similar to that observed previously in mice lacking β-catenin in osteoblasts. Likewise, calvarial cells doubly deficient for Lrp5 and Lrp6 failed to form osteoblasts when cultured in osteogenic media, but instead attained a chondrocyte-like phenotype. These results indicate that expression of both Lrp5 and Lrp6 are required within mature osteoblasts for normal postnatal bone development

LRP5 and LRP6 Are Not Required for Protective Antigen–Mediated Internalization or Lethality of Anthrax Lethal Toxin

Anthrax toxin (AnTx) plays a key role in the pathogenesis of anthrax. AnTx is composed of three proteins: protective antigen (PA), edema factor, and lethal factor (LF). PA is not toxic but serves to bind cells and translocate the toxic edema factor or LF moieties to the cytosol. Recently, the low-density lipoprotein receptor–related protein LRP6 has been reported to mediate internalization and lethality of AnTx. Based on its similarity to LRP6, we hypothesized that LRP5 may also play a role in cellular uptake of AnTx. We assayed PA-dependent uptake of anthrax LF or a cytotoxic LF fusion protein (FP59) in cells and mice harboring targeted deletions of Lrp5 or Lrp6. Unexpectedly, we observed that uptake was unaltered in the presence or absence of either Lrp5 or Lrp6 expression. Moreover, we observed efficient PA-mediated uptake into anthrax toxin receptor (ANTXR)–deficient Chinese hamster ovary cells (PR230) that had been stably engineered to express either human ANTXR1 or human ANTXR2 in the presence or absence of siRNA specific for LRP5 or LRP6. Our results demonstrate that neither LRP5 nor LRP6 is necessary for PA-mediated internalization or lethality of anthrax lethal toxin

Estimating the glutamate transporter surface density in distinct sub-cellular compartments of mouse hippocampal astrocytes

Glutamate transporters preserve the spatial specificity of synaptic transmission by limiting glutamate diffusion away from the synaptic cleft, and prevent excitotoxicity by keeping the extracellular concentration of glutamate at low nanomolar levels. Glutamate transporters are abundantly expressed in astrocytes, and previous estimates have been obtained about their surface expression in astrocytes of the rat hippocampus and cerebellum. Analogous estimates for the mouse hippocampus are currently not available. In this work, we derive the surface density of astrocytic glutamate transporters in mice of different ages via quantitative dot blot. We find that the surface density of glial glutamate transporters is similar in 7-8 week old mice and rats. In mice, the levels of glutamate transporters increase until about 6 months of age and then begin to decline slowly. Our data, obtained from a combination of experimental and modeling approaches, point to the existence of stark differences in the density of expression of glutamate transporters across different sub-cellular compartments, indicating that the extent to which astrocytes limit extrasynaptic glutamate diffusion depends not only on their level of synaptic coverage, but also on the identity of the astrocyte compartment in contact with the synapse. Together, these findings provide information on how heterogeneity in the spatial distribution of glutamate transporters in the plasma membrane of hippocampal astrocytes my alter glutamate receptor activation out of the synaptic cleft

(Young Scholars) Effects of feed truck unloading and swine barn feed line location on pellet quality and nutrient segregation

Citation: De Jong, J. A., DeRouchey, J. M., Tokach, M. D., Goodband, R. D., Woodworth, J. C., Jones, C. K., . . . Haberl, B. (2016). (Young Scholars) Effects of feed truck unloading and swine barn feed line location on pellet quality and nutrient segregation. Journal of Animal Science, 94, 78-78. doi:10.2527/msasas2016-166Two experiments were conducted at a commercial feed mill and 6 commercial wean to finish pig sites to determine the effects of feed truck unloading auger RPM on pellet quality and unloading time, and the effects of feed line location on pellet quality and nutrient concentration of intact pellets and their fines. In Exp. 1, pelleted feed was unloaded using 3 speeds (900, 1150, and 1400 RPM) from each of 8 compartments of a feed truck (Walinga Inc., Guelph, ON, Canada). Six samples per compartment were collected creating 16 replications/unloading speed. There was an unloading speed × trailer compartment interaction (P = 0.031; SEM = 17.4). The difference in unloading time from the front to rear compartment was greatest at the slowest unloading speed and similar at the 2 highest unloading speeds (70 vs. 35 and 37 s). The percentage of fines formed during unloading was not influenced by unloading speed, but tended to increase (quadratic; P = 0.081; SEM = 2.27) from the front (8.2%) to the rear compartment (10.7%). In Exp. 2, pelleted feed samples were collected during unloading into a commercial feed bin at 6 finishing pig sites with 2 feed lines, resulting in 12 replications per feed line location. Samples were collected from the feed line at 6, 35, and 76 m from the feed bin. There were no interactions between feed line location and nutrient profile of the fines and pellets. There was no effect of feed line location on pellet durability index, percentage fines, percentage fines formed, or the nutrient profile of pellets or fines. Across locations, fines had decreased (P < 0.05) CP (12.4 vs. 15.3%; SEM = 0.14) and P (0.37 vs. 0.40%; SEM = 0.006), but greater (P < 0.05) ADF (3.7 vs. 3.2%; SEM = 0.24), crude fiber (2.7 vs. 2.2%; SEM = 0.09), Ca (0.47 vs. 0.44%; SEM = 0.012), ether extract (6.2 vs. 5.2%; SEM = 0.11), and starch (47.4 vs. 44.7%; SEM = 0.42) for the fines and pellets, respectively. In conclusion, the front compartments closer to the truck cab resulted in fewer fines formed from loading to unloading. Decreasing unloading speed significantly increased the amount of time taken to unload a feed truck but did not alter fines formed. Feeder distance from the bin did not influence fines formation. There were significant differences in nutrient profile between fines and pellets. Understanding the location of fines creation during the feed delivery process may allow for alternative methods to reduce the formation of fines and subsequent nutrient segregation