3D printing for bio-synthetic biliary stents

Three-dimensional (3D) printing is an additive manufacturing method that holds great potential in a variety of future patient-specific medical technologies. This project validated a novel crosslinked polyvinyl alcohol (XL-PVA) 3D printed stent infused with collagen, human placental mesenchymal stem cells (PMSCs), and cholangiocytes. The biofabrication method in the present study examined 3D printing and collagen injection molding for rapid prototyping of customized living biliary stents with clinical applications in the setting of malignant and benign bile duct obstructions. XL-PVA stents showed hydrophilic swelling and addition of radiocontrast to the stent matrix improved radiographic opacity. Collagen loaded with PMSCs contracted tightly around hydrophilic stents and dense choloangiocyte coatings were verified through histology and fluorescence microscopy. It is anticipated that design elements used in these stents may enable appropriate stent placement, provide protection of the stent-stem cell matrix against bile constituents, and potentially limit biofilm development. Overall, this approach may allow physicians to create personalized bio-integrating stents for use in biliary procedures and lays a foundation for new patient-specific stent fabrication techniques

High-throughput scaffold-free microtissues through 3D printing

Abstract Background Three-dimensional (3D) cell cultures and 3D bioprinting have recently gained attention based on their multiple advantages over two-dimensional (2D) cell cultures, which have less translational potential to recapitulate human physiology. 3D scaffold supports, cell aggregate systems and hydrogels have been shown to accurately mimic native tissues and support more relevant cell-cell interactions for studying effects of drugs and bioactive agents on cells in 3D. The development of cost-effective, high-throughput and scaffold-free microtissue assays remains challenging. In the present study, consumer grade 3D printing was examined as a fabrication method for creation of high-throughput scaffold-free 3D spheroidal microtissues. Results Consumer grade 3D printing was capable of forming 96-well cell culture inserts to create scaffold-free microtissues in liquid suspensions. The inserts were seeded with human glioblastoma, placental-derived mesenchymal stem cells, and intestinal smooth muscle cells. These inserts allowed for consistent formation of cell density-controllable microtissues that permit screening of bioactive agents. Conclusion A variety of different cell types, co-cultures, and drugs may be evaluated with this 3D printed microtissue insert. It is suggested that the microtissue inserts may benefit 3D cell culture researchers as an economical assay solution with applications in pharmaceuticals, disease modeling, and tissue-engineering

Use of Metagenomic Shotgun Sequencing Technology To Detect Foodborne Pathogens within the Microbiome of the Beef Production Chain

Foodborne illnesses associated with pathogenic bacteria are a global public health and economic challenge. The diversity of microorganisms (pathogenic and nonpathogenic) that exists within the food and meat industries complicates efforts to understand pathogen ecology. Further, little is known about the interaction of pathogens within the microbiome throughout the meat production chain. Here, a metagenomic approach and shotgun sequencing technology were used as tools to detect pathogenic bacteria in environmental samples collected from the same groups of cattle at different longitudinal processing steps of the beef production chain: cattle entry to feedlot, exit from feedlot, cattle transport trucks, abattoir holding pens, and the end of the fabrication system. The log read counts classified as pathogens per million reads for Salmonella enterica, Listeria monocytogenes, Escherichia coli, Staphylococcus aureus, Clostridium spp. (C. botulinum and C. perfringens), and Campylobacter spp. (C. jejuni, C. coli, and C. fetus) decreased over subsequential processing steps. Furthermore, the normalized read counts for S. enterica, E. coli, and C. botulinum were greater in the final product than at the feedlots, indicating that the proportion of these bacteria increased (the effect on absolute numbers was unknown) within the remaining microbiome. From an ecological perspective, data indicated that shotgun metagenomics can be used to evaluate not only the microbiome but also shifts in pathogen populations during beef production. Nonetheless, there were several challenges in this analysis approach, one of the main ones being the identification of the specific pathogen from which the sequence reads originated, which makes this approach impractical for use in pathogen identification for regulatory and confirmation purposes

Use of Metagenomic Shotgun Sequencing Technology To Detect Foodborne Pathogens within the Microbiome of the Beef Production Chain.

Foodborne illnesses associated with pathogenic bacteria are a global public health and economic challenge. The diversity of microorganisms (pathogenic and nonpathogenic) that exists within the food and meat industries complicates efforts to understand pathogen ecology. Further, little is known about the interaction of pathogens within the microbiome throughout the meat production chain. Here, a metagenomic approach and shotgun sequencing technology were used as tools to detect pathogenic bacteria in environmental samples collected from the same groups of cattle at different longitudinal processing steps of the beef production chain: cattle entry to feedlot, exit from feedlot, cattle transport trucks, abattoir holding pens, and the end of the fabrication system. The log read counts classified as pathogens per million reads for Salmonella enterica,Listeria monocytogenes,Escherichia coli,Staphylococcus aureus, Clostridium spp. (C. botulinum and C. perfringens), and Campylobacter spp. (C. jejuni,C. coli, and C. fetus) decreased over subsequential processing steps. Furthermore, the normalized read counts for S. enterica,E. coli, and C. botulinumwere greater in the final product than at the feedlots, indicating that the proportion of these bacteria increased (the effect on absolute numbers was unknown) within the remaining microbiome. From an ecological perspective, data indicated that shotgun metagenomics can be used to evaluate not only the microbiome but also shifts in pathogen populations during beef production. Nonetheless, there were several challenges in this analysis approach, one of the main ones being the identification of the specific pathogen from which the sequence reads originated, which makes this approach impractical for use in pathogen identification for regulatory and confirmation purposes

National Beef Quality Audit–2016: assessment of cattle hide characteristics, offal condemnations, and carcass traits to determine the quality status of the market cow and bull beef industry

To continue the series that began in 1994, the National Beef Quality Audit (NBQA) – 2016 was conducted to quantify the quality status of the market cow and bull beef sector, as well as determine improvements made in the beef and dairy industry since 2007. The NBQA-2016 was conducted from March through December of 2016, and assessed hide-on carcasses (n = 5,278), chilled carcasses (n = 4,285), heads (n = 5,720), and offal items (n = 4,800) in 18 commercial processing facilities throughout the United States. Beef cattle were predominantly black-hided; 68.0% of beef cows and 67.2% of beef bulls possessed a black hide. Holstein was the predominant type of dairy animal observed. Just over half (56.0%) of the cattle surveyed had no mud contamination on the hide, and when mud was present, 34.1% of cattle only had small amounts. Harvest floor assessments found 44.6% of livers, 23.1% of lungs, 22.3% of hearts, 20.0% of viscera, 8.2% of heads, and 5.9% of tongues were condemned. Liver condemnations were most frequently due to abscess presence. In contrast, contamination was the primary reason for condemnation of all other offal items. Of the cow carcasses surveyed, 17.4% carried a fetus at the time of harvest. As expected, mean carcass weight and loin muscle area values observed for bulls were heavier and larger than cows. The marbling scores represented by cull animal carcasses were most frequently slight and traces amounts. Cow carcasses manifested a greater amount of marbling on average than bull carcasses. The predominant fat color score showed all carcasses surveyed had some level of yellow fat. Only 1.3% of carcasses exhibited signs of arthritic joints. Results of the NBQA-2016 indicate there are areas in which the beef and dairy industries have improved and areas that still need attention to prevent value loss in market cows and bulls

Continuous Glucose Monitoring Profiles in Healthy Non-Diabetic Participants: A Multicenter Prospective Study

CONTEXT: Use of continuous glucose monitoring (CGM) is increasing for insulin-requiring patients with diabetes. While data on glycemic profiles of healthy, non-diabetic individuals exists for older sensors, assessment of glycemic metrics with new generation CGM devices is lacking. OBJECTIVE: To establish reference sensor glucose ranges in healthy, non-diabetic individuals across different age groups, using a current generation CGM sensor. DESIGN: Multicenter, prospective study. SETTING: 12 centers within the T1D Exchange Clinic Network. PATIENTS OR PARTICIPANTS: Non-pregnant, healthy, non-diabetic children and adults (age ≥6 years); with non-obese body mass index. INTERVENTION: A blinded Dexcom G6 CGM, with once daily calibration, was worn for up to 10 days in each participant. MAIN OUTCOME MEASURE: CGM metrics of mean glucose, hyperglycemia, hypoglycemia, and glycemic variability. RESULTS: 153 participants (age 7-80 years) were included in the analyses. Mean average glucose was 98-99 mg/dL (5.4-5.5 mmol/L) for all age groups except those over 60 years in whom mean average glucose was 104 mg/dL (5.8 mmol/L). The median % time between 70-140 mg/dL (3.9-7.8 mmol/L) was 96% (IQR 93%-98%). Mean within-individual coefficient of variation (CV) was 17±3%. Median time spent with glucose levels \u3e140mg/dL was 2.1% (30 min/day) and/dL (3.9 mmol/L) was 1.1% (15 min/day). CONCLUSION: By assessing across age groups in a healthy, non-diabetic population, normative sensor glucose data have been derived, and will be useful as a benchmark for future research studies

Characterization of the Microbial Resistome in Conventional and "Raised Without Antibiotics" Beef and Dairy Production Systems.

Metagenomic investigations have the potential to provide unprecedented insights into microbial ecologies, such as those relating to antimicrobial resistance (AMR). We characterized the microbial resistome in livestock operations raising cattle conventionally (CONV) or without antibiotic exposures (RWA) using shotgun metagenomics. Samples of feces, wastewater from catchment basins, and soil where wastewater was applied were collected from CONV and RWA feedlot and dairy farms. After DNA extraction and sequencing, shotgun metagenomic reads were aligned to reference databases for identification of bacteria (Kraken) and antibiotic resistance genes (ARGs) accessions (MEGARes). Differences in microbial resistomes were found across farms with different production practices (CONV vs. RWA), types of cattle (beef vs. dairy), and types of sample (feces vs. wastewater vs. soil). Feces had the greatest number of ARGs per sample (mean = 118 and 79 in CONV and RWA, respectively), with tetracycline efflux pumps, macrolide phosphotransferases, and aminoglycoside nucleotidyltransferases mechanisms of resistance more abundant in CONV than in RWA feces. Tetracycline and macrolide-lincosamide-streptogramin classes of resistance were more abundant in feedlot cattle than in dairy cow feces, whereas the β-lactam class was more abundant in dairy cow feces. Lack of congruence between ARGs and microbial communities (procrustes analysis) suggested that other factors (e.g., location of farms, cattle source, management practices, diet, horizontal ARGs transfer, and co-selection of resistance), in addition to antimicrobial use, could have impacted resistome profiles. For that reason, we could not establish a cause-effect relationship between antimicrobial use and AMR, although ARGs in feces and effluents were associated with drug classes used to treat animals according to farms' records (tetracyclines and macrolides in feedlots, β-lactams in dairies), whereas ARGs in soil were dominated by multidrug resistance. Characterization of the "resistance potential" of animal-derived and environmental samples is the first step toward incorporating metagenomic approaches into AMR surveillance in agricultural systems. Further research is needed to assess the public-health risk associated with different microbial resistomes