Synthetic polymer coatings diminish chronic inflammation risk in large ECM-based materials.

Degradable materials that can support cell infiltration and remodeling are the basis of tissue engineered approaches to vascular repair. In addition, to replace or close a large area of the vasculature, a patch material or scaffold must also withstand high pressure over time. Extracellular matrix-based (ECM-based) scaffolds offer a biological substrate with environmental cues that can support the formation of appropriate vascular tissue. However, scaffolds made from pure natural materials can degrade rapidly, resulting in reduced mechanical integrity of the implant and possible chronic inflammation in the site. A hybrid biomaterial, combining the matrix-dense tissue pericardium with a layer of the degradable polymer poly(propylene fumarate) (PPF), is suited to withstand rapid enzymatic degradation and control the presentation of an unaltered natural tissue matrix for remodeling activity. In this study, we show that the polymer reinforced hybrid supports cellular infiltration, but has fewer macrophages in the vicinity of the implant after 6 weeks in vivo than an untreated tissue control in both athymic and immunocompetent rat models. This result is supported by changes seen in other inflammatory cell populations. Based on significant differences in the inflammatory response to untreated pericardium and PPF-reinforced pericardium, we conclude that the polymer reinforcement layer can be used as a tool to leverage presentation of the ECM molecules in ECM-based scaffolds. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 107A: 494-504, 2019.

Three dimensional extrusion printing induces polymer molecule alignment and cell organization within engineered cartilage.

Proper cell-material interactions are critical to remain cell function and thus successful tissue regeneration. Many fabrication processes have been developed to create microenvironments to control cell attachment and organization on a three-dimensional (3D) scaffold. However, these approaches often involve heavy engineering and only the surface layer can be patterned. We found that 3D extrusion based printing at high temperature and pressure will result an aligned effect on the polymer molecules, and this molecular arrangement will further induce the cell alignment and different differentiation capacities. In particular, articular cartilage tissue is known to have zonal collagen fiber and cell orientation to support different functions, where collagen fibers and chondrocytes align parallel, randomly, and perpendicular, respectively, to the surface of the joint. Therefore, cell alignment was evaluated in a cartilage model in this study. We used small angle X-ray scattering analysis to substantiate the polymer molecule alignment phenomenon. The cellular response was evaluated both in vitro and in vivo. Seeded mesenchymal stem cells (MSCs) showed different morphology and orientation on scaffolds, as a combined result of polymer molecule alignment and printed scaffold patterns. Gene expression results showed improved superficial zonal chondrogenic marker expression in parallel-aligned group. The cell alignment was successfully maintained in the animal model after 7 days with distinct MSC morphology between the casted and parallel printed scaffolds. This 3D printing induced polymer and cell alignment will have a significant impact on developing scaffold with controlled cell-material interactions for complex tissue engineering while avoiding complicated surface treatment, and therefore provides new concept for effective tissue repairing in future clinical applications. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2190-2199, 2018.

Surveys suck: Consumer preferences when purchasing genetically engineered foods.

Many studies have attempted to gauge consumers' acceptance of genetically engineered or modified (GM) foods. Surveys, asking people about attitudes and intentions, are easy-to-collect proxies of consumer behavior. However, participants tend to respond as citizens of society, not discrete individuals, thereby inaccurately portraying their potential behavior. The Theory of Planned Behavior improved the accuracy of self-reported information, but its limited capacity to account for intention variance has been attributed to the hypothetical scenarios to which survey participants must respond. Valuation methods, asking how much consumers may be willing to pay or accept for GM foods, have revealed that consumers are usually willing to accept them at some price, or in some cases willing to pay a premium. Ultimately, it's consumers' actual--not intended--behavior that is of most interest to policy makers and business decision-makers. Real choice experiments offer the best avenue for revealing consumers' food choices in normal life.

Evaluation of a hand hygiene campaign in outpatient health care clinics.

OBJECTIVE: To improve hand hygiene in two outpatient health care clinics through the introduction of a gel sanitizer and an informational poster. METHODS: In this interventional study, health care workers at two outpatient clinics were observed for frequency of hand hygiene (attempts versus opportunities). Gel sanitizer and informational posters were introduced together as an intervention. Direct observation of the frequency of hand hygiene was performed during baseline, intervention, and follow-up. A poststudy survey of health care workers was also distributed and collected. RESULTS: In both clinics, the frequency of hand hygiene was poor at baseline (11% and 21%) but improved significantly after intervention (36% and 54%) and was maintained through the follow-up period (32% and 51%). Throughout the study, postcontact hand hygiene was observed significantly more often than precontact hand hygiene. In both clinics, health care workers reported a preference for soap and water; yet observations showed that when the intervention made gel sanitizer available, sanitizer use predominated. Fifty percent of the surveyed health care workers considered the introduction of gel sanitizer to be an effective motivating tool for improving hand hygiene. CONCLUSIONS: Hand hygiene performance by health care workers in outpatient clinics may be improved through promoting the use of gel sanitizer and using informational posters. Compared with surveys, direct observation by trained observers may provide more accurate information about worker preferences for hand hygiene tools.

Investigating the potential benefits of on-site food safety training for Folklorama, a temporary food service event.

Folklorama in Winnipeg, Manitoba, Canada, is a 14-day temporary food service event that explores the many different cultural realms of food, food preparation, and entertainment. In 2010, the Russian pavilion at Folklorama was implicated in a foodborne outbreak of Escherichia coli O157 that caused 37 illnesses and 18 hospitalizations. The ethnic nature and diversity of foods prepared within each pavilion presents a unique problem for food inspectors, as each culture prepares food in their own very unique way. The Manitoba Department of Health and Folklorama Board of Directors realized a need to implement a food safety information delivery program that would be more effective than a 2-h food safety course delivered via PowerPoint slides. The food operators and event coordinators of five randomly chosen pavilions selling potentially hazardous food were trained on-site, in their work environment, focusing on critical control points specific to their menu. A control group (five pavilions) did not receive on-site food safety training and were assessed concurrently. Public health inspections for all 10 pavilions were performed by Certified Public Health Inspectors employed with Manitoba Health. Critical infractions were assessed by means of standardized food protection inspection reports. The results suggest no statistically significant difference in food inspection scores between the trained and control groups. However, it was found that inspection report results increased for both the control and trained groups from the first inspection to the second, implying that public health inspections are necessary in correcting unsafe food safety practices. The results further show that in this case, the 2-h food safety course delivered via slides was sufficient to pass public health inspections. Further evaluations of alternative food safety training approaches are warranted.

Government management of two media-facilitated crises involving dioxin contamination of food.

Incidents become crises through a constant and intense public scrutiny facilitated by the media. Two incidents involving dioxin contamination of food led to crises in Belgium and the Republic of Ireland in 1999 and 2008, respectively. Thought to cause cancer in humans, dioxins reached the food supply in both incidents through the contamination of fat used for animal feed. The food and agricultural industries connected to each incident relied on crisis management activities of federal governments to limit adverse public reaction. Analysis of the management of the two crises by their respective federal governments, and a subsequent review of crisis management literature, led to the development of an effective crisis management model. Such a model, appropriately employed, may insulate industries associated with a crisis against damaged reputations and financial loss.

Observation-based evaluation of hand hygiene practices and the effects of an intervention at a public hospital cafeteria.

BACKGROUND: Hand hygiene is important before meals, especially in a hospital cafeteria where patrons may have had recent contact with infectious agents. Few interventions to improve hand hygiene have had measureable success. This study was designed to use a poster intervention to encourage hand hygiene among health care workers (HCWs) and hospital visitors (HVs) upon entry to a hospital cafeteria. METHODS: Over a 5-week period, a poster intervention with an accessible hand sanitizer unit was deployed to improve hand hygiene in a hospital cafeteria. The dependent variable observed was hand hygiene attempts. Study phases included a baseline, intervention, and follow-up phase, with each consisting of 3 randomized days of observation for 3 hours during lunch. RESULTS: During the 27 hours of observation, 5,551 participants were observed, and overall hand hygiene frequency was 4.79%. Hygiene attempts occurred more frequently by HCWs than HVs (P = .0008) and females than males (P = .0281). Hygiene attempts occurred more frequently after poster introduction than baseline (P = .0050), and this improvement was because of an increase in frequency of HV hand hygiene rather than HCW hand hygiene. CONCLUSION: The poster intervention tool with easily accessible hand sanitizer can improve overall hand hygiene performance in a US hospital cafeteria.

University students' hand hygiene practice during a gastrointestinal outbreak in residence: what they say they do and what they actually do.

Published research on outbreaks of gastrointestinal illness has focused primarily on the results of epidemiological and clinical data collected postoutbreak; little research has been done on actual preventative practices during an outbreak. In this study, the authors observed student compliance with hand hygiene recommendations at the height of a suspected norovirus outbreak in a university residence in Ontario, Canada. Data on observed practices was compared to postoutbreak self-report surveys administered to students to examine their beliefs and perceptions about hand hygiene. Observed compliance with prescribed hand hygiene recommendations occurred 17.4% of the time. Despite knowledge of hand hygiene protocols and low compliance, 83.0% of students indicated that they practiced correct hand hygiene during the outbreak. To proactively prepare for future outbreaks, a current and thorough crisis communications and management strategy, targeted at a university student audience and supplemented with proper hand washing tools, should be enacted by residence administration.

Long-range recombination gradient between HIV-1 subtypes B and C variants caused by sequence differences in the dimerization initiation signal region.

HIV-1 intersubtype recombinants have an increasingly important role in shaping the AIDS pandemic. We sought to understand the molecular mechanisms that generate intersubtype HIV-1 recombinants. We analyzed recombinants of HIV-1 subtypes B and C, and identified their crossover junctions in the viral genome from the 5' long terminal repeat (LTR) to the end of pol. We identified 56 recombination events in 56 proviruses; the distribution of these events indicated an apparent recombination gradient: there were significantly more crossover junctions in the 3' half than in the 5' half of the region analyzed. HIV-1 subtypes B and C have different dimerization initiation signal (DIS). We hypothesized that the inability of subtype B and C RNAs to form perfect base-pairing of the DIS affects the dimeric RNA structure and causes a decrease in recombination events at the 5' end of the viral genome. To test this hypothesis, we examined recombinants generated from a subtype C virus and a modified subtype B virus containing a subtype C DIS. In the 56 proviruses analyzed, we identified 96 recombination events, which are significantly more frequent than in the B/C recombinants. Furthermore, these crossover junctions were distributed evenly throughout the region analyzed, indicating that the recombination gradient was corrected by matching the DIS. Therefore, base-pairing at the DIS has an important function during HIV-1 reverse transcription, most likely in maintaining nucleic-acid structure in the complex. These findings reveal elements important to retroviral recombination and provide insights into the generation of HIV-1 intersubtype recombinants that are important to the AIDS epidemic.

HGPRT mutation induction by N-ethyl-N-nitrosourea as measured by 6-thioguanine resistance is higher in male than in female Syrian hamster fetuses.

BACKGROUND: The consequences of mutations in embryonic and fetal cells are serious and contribute to high prenatal sensitivity to mutagenic agents. An understanding of the factors that influence the yield of such mutations is important for management of adverse effects of perinatal exposures. Resistance to 6-thioguanine (6-TG) can be utilized to study mutational events at the hypoxanthine-guanine phosphoribosyl transferase (HGPRT) locus. HGPRT is X-linked and recessive. According to the Lyon hypothesis, male cells have only one X-chromosome and female cells randomly inactivate the second X-chromosome. This leads to the prediction that X-linked genes should be equally sensitive to the mutagenic effects of toxicants in male and female fetuses. METHODS: We tested this supposition by in utero exposure of Syrian hamster fetuses to N-ethyl-N-nitrosourea (ENU) at day 12 of gestation. ENU is a strong carcinogen and mutagen. HGPRT mutations were detected by selection with 6-TG. RESULTS: Surprisingly. the male cells had 4 to 5 times more 6-TG mutants than female cells, in two separate experiments (p<0.001). Ouabain resistance, reflecting a co-dominant autosomal locus, was used as a control, and we found that there was no significant difference between male and female cells (p=0.549). CONCLUSIONS: Possible reasons for the sex difference in mutations include escape of the second X-chromosome from inactivation in some of the female cells, or higher mutability in male cells. In any event, there is a gender difference in vulnerability to mutation of an X-linked gene that has previously not been appreciated, and that may be relevant to toxicological studies of such genes. HGPRT is frequently used to monitor mutagenic events in human fetuses.

Urogenital carcinogenesis in female CD1 mice induced by in utero arsenic exposure is exacerbated by postnatal diethylstilbestrol treatment.

Transplacental inorganic arsenic carcinogenicity, together with postnatal exposure to diethylstilbestrol or tamoxifen, was studied. Pregnant CD1 mice received 85 ppm arsenic in the drinking water from gestation days 8 to 18 and were allowed to give birth. Groups (n = 35) of female offspring were injected s.c. on postpartum days 1 through 5 with diethylstilbestrol (2 microg/pup/d) or tamoxifen (10 microg/pup/d) and observed for 90 weeks. Arsenic alone induced some urogenital system tumors, including mostly benign tumors of the ovary and uterus, and adrenal adenoma. Diethylstilbestrol alone induced some tumors (primarily cervical) but when given after in utero arsenic, it greatly enhanced urogenital tumor incidence, multiplicity, and progression. For instance, compared with the incidence of urogenital malignancies in the control (0%), arsenic alone (9%), and diethylstilbestrol alone (21%) groups, arsenic plus diethylstilbestrol acted synergistically, inducing a 48% incidence of malignant urogenital tumors. Of the urogenital tumors induced by arsenic plus diethylstilbestrol, 80% were malignant, and 55% were multiple site. Arsenic plus diethylstilbestrol increased ovarian, uterine, and vaginal tumors, and urinary bladder proliferative lesions, including three transitional cell carcinomas. Tamoxifen alone did not increase urogenital tumors or affect arsenic-induced neoplasia but did increase arsenic-induced uroepithelial proliferative lesions. Uterine and bladder carcinoma induced by arsenic plus diethylstilbestrol greatly overexpressed estrogen receptor-alpha (ER-alpha) and pS2, an estrogen-regulated gene. In neonatal uteri, prenatal arsenic increased ER-alpha expression and enhanced estrogen-related gene expression induced by postnatal diethylstilbestrol. Thus, arsenic acts with estrogens to enhance production of female mouse urogenital cancers.

Tumor suppression and normal aging in mice with constitutively high p53 activity.

The p53 inhibitor murine double-minute gene 2 (Mdm2) is a target for potential cancer therapies, however increased p53 function can be lethal. To directly address whether reduced Mdm2 function can inhibit tumorigenesis without causing detrimental side effects, we exploited a hypomorphic murine allele of mdm2 to compare the effects of decreased levels of Mdm2 and hence increased p53 activity on tumorigenesis and life span in mice. Here we report that mice with decreased levels of Mdm2 are resistant to tumor formation yet do not age prematurely, supporting the notion that Mdm2 is a promising target for cancer therapeutics.

Injectable formulation of disodium 1-[2-(carboxylato)pyrrolidin-1-yl]diazen-1-ium-1,2-diolate (PROLI/NO), an ultrafast nitric oxide donor prodrug.

PROLI/NO is an agent of structure XN(O)==NONa (X = L-prolyl) whose 2-s half-life for nitric oxide (NO) release at physiological pH makes it an excellent prodrug for localizing NO's therapeutic effects at the site of application, but a difficult one to formulate and certify as pure. Despite its extraordinary thermal and hydrolytic instability, however, PROLI/NO could be formulated as an injectable drug by dissolving it in cold 0.1 M sodium hydroxide containing 5% D-mannitol, then quickly ultrafiltering and lyophilizing it in evacuated septum vials. No evidence for decomposition was seen in the contents of these evacuated vials when stored at -20 degrees C over a 140-day observation period, as judged by quantifying NO release in simulated infusate solutions (10 mM carbonate/bicarbonate, pH 10.5). The only hydrolysis products detected were NO, nitrite ion, proline, and N-nitrosoproline, all products of normal human physiological processes.

Carcinosarcoma of the maxilla in a squirrel monkey (Saimiri sciureus).

We present the first, to our knowledge, described case of carcinosarcoma of the maxilla in a squirrel monkey. Carcinosarcomas are rare tumors of the upper aerodigestive tract, and consist of carcinomatous and sarcomatous tissue. Histologic analysis revealed a neoplasm composed of an adenocarcinomatous component (epithelial element) and a mesenchymal component (sarcomatous element). Metastatic growth was documented in the lung tissue and the submandibular lymph node. The histolopathologic findings, the pattern of metastasis, and the clinical progression closely resembled those of carcinosarcoma involving salivary glands in humans.

Gene expression dose-response changes in microarrays after exposure of human peripheral lung epithelial cells to nickel(II).

Occupational exposure to nickel compounds is associated with lung cancer risk; both genotoxic and epigenetic mechanisms have been proposed. For comprehensive examination of the acute effects of nickel(II) acetate on gene expression in cultured human peripheral lung epithelial HPL1D cells, microarray analyses were carried out with cDNA chips (approximately 8000 cDNAs). Cells were exposed for 24 h to nontoxic (50, 100, and 200 microM) or toxic (400, 800, and 1600 microM) nickel(II) concentrations. Cluster analysis was applied to the 868 genes with > or = 2-fold change at any concentration. Two main clusters showed marked up- or down-regulation at the highest, toxic concentrations. The data further subdivided into 10 highly cohesive clusters with high probability, and of these only 2 had the same response trend at low nontoxic as at high concentrations, an observation of clear relevance to the process of high- to low-dose extrapolation in risk assessment. There were 113 genes showing > or = 2-fold change at the three lower nontoxic concentrations, those most relevant to in vivo carcinogenesis. In addition to expected responses of metallothionein, ferritin, and heat-shock proteins, the results revealed for the first time changed expression of some potential cancer-related genes in response to low-dose Ni(II): RhoA, dyskerin, interferon regulatory factor 1, RAD21 homologue, and tumor protein, translationally controlled. Overall, most of the genes impacted by nontoxic concentrations of nickel(II) acetate related to gene transcription, protein synthesis and stability, cytoskeleton, signaling, metabolism, cell membrane, and extracellular matrix.

Implementation and analysis of an on-farm food safety program for the production of greenhouse vegetables.

Fresh fruits and vegetables are increasingly being recognized as vectors for foodborne illness. In 1998, an on-farm food safety program was developed for the Ontario Greenhouse Vegetable Growers (OGVG) in Ontario, Canada. This hazard analysis critical control point-based system was designed to reduce the potential of microbial contamination along the entire production and distribution process. A previous report (D. A. Powell, M. Bobadilla-Ruiz, A. Whitfield, M. W. Griffiths, and A. Luedtke, J. Food Prot. 65:918-923) outlined the first 2 years of the program; the present report documents the third year of the program's implementation. Through individual on-site grower visits and the microbiological testing of produce and water, the program's OGVG member requirements were determined, and the program's success was assessed. Growers' knowledge, understanding, and awareness of microbial risks associated with fresh produce have increased, and improvements in practices used in greenhouses and packing sheds were noted.

VIRTUAL2D: A web-accessible predictive database for proteomics analysis.

The available archive of sequence databases compiled from whole genome projects and budding proteomics efforts have enabled us to develop VIRTUAL2D, an interactive system for the assembly of virtual protein expression maps computed on the basis of theoretical isoelectric focusing point, molecular weight, tissue specificity and relative abundance for any set of proteins currently catalogued. This tool will assist in the preliminary, albeit putative, prediction of the identity and location of unknown and/or low abundance proteins in experimentally derived two-dimensional polyacrylamide gel electrophoresis maps.

Robustness of the Chen-Dougherty-Bittner procedure against non-normality and heterogeneity in the coefficient of variation.

Chen, Dougherty, and Bittner [Y. Chen, E. R. Dougherty, and M. L. Bittner, J. Biomed. Opt. 2(4), 364-374 (1997)] provided the derivation of a probability density function (PDF) for a signal ratio from a DNA microarray. This PDF is potentially useful for testing whether a pair of signals from the same gene has a common mean. The derivation of the PDF assumes the normality of all signal distributions and a common coefficient of variation (CV) for all signals within a microarray. The testing procedure requires the calculation of a common confidence interval for a microarray, based on a maximum likelihood estimator of the "common" CV, and the determination of whether or not a ratio for a particular gene falls within this interval. This study used Monte Carlo techniques and demonstrated that the procedure is robust to violations of normality and also to constancy in the coefficients of variation. A closer examination of the dynamics of the procedure found that the robustness was the result of offsetting effects. The size of the confidence interval was increased as a result of higher estimates of the common CV, as the actual CV pattern became heterogeneous. This effect mitigated the inflation in the size of the ratio as a result of increasing CV heterogeneity. These findings suggest that the Chen-Dougherty-Bittner procedure may be used even if underlying assumptions do not hold.

Development, implementation, and analysis of an on-farm food safety program for the production of greenhouse vegetables.

Fresh fruits and vegetables are increasingly recognized as vectors for foodborne illness. Consequently, an on-farm food safety program was developed, implemented, and analyzed for the Ontario Greenhouse Vegetable Growers in Ontario, Canada, during a 2 1/2-year period. This hazard analysis critical control point-based system was designed to reduce the potential of microbial contamination along the entire production and distribution process. Through the use of microbiological testing, on-site visits, and producer surveys, it was determined that the program has increased grower knowledge, understanding, and awareness of microbial risks associated with fresh produce and caused improvements in practices used within the greenhouse and packing sheds.

Multidrug-resistance mdr1a/1b double knockout mice are more sensitive than wild type mice to acute arsenic toxicity, with higher arsenic accumulation in tissues.

Arsenic is an environmental toxicant. Active extrusion via the ArsAB pump is a mechanism for arsenic detoxication in bacteria. However, how arsenic is effluxed from mammalian cells is not completely known. Our recent work shows that acquired arsenic resistance is associated with overexpression of P-glycoprotein and can be reversed by PSC833, an inhibitor for P-glycoprotein. This study utilized the mdr1a/1b(-/-) mice, which lack mdr1-type P-glycoproteins, to examine whether these mice are sensitive to arsenic toxicity and have higher arsenic accumulation in their tissues. The mdr1a/1b(-/-) and wild-type FVB mice were given arsenic as sodium arsenite (12-19 mg/kg, sc) and toxicity was examined 24 h later. The mdr1a/1b(-/-) mice were more sensitive than wild-type mice to arsenite-induced lethality, with LD(50) of 14.5 and 17 mg/kg, respectively. Histologically, arsenite produced more frequent and more severe lesions in the liver and kidney of the mdr1a/1b(-/-) mice than in wild-type mice. Serum alanine aminotransferase activity and blood urea nitrogen levels, indicative of hepatic and renal damage respectively, were increased 4 to 6-fold in the mdr1a/1b(-/-) mice as compared with 1-2-fold increases in wild-type mice. The mdr1a/1b(-/-) mice accumulated more arsenic in the liver (15.3 vs. 5.2 microg/g), kidney (7.23 vs. 3.22 microg/g), small intestine (3.98 vs. 1.57 microg/g) and brain (0.45 vs. 0.17 microg/g), as compared with wild-type mice 24 h after sodium arsenite (14 mg/kg, s.c.) administration. In summary, this study demonstrated that the mdr1a/1b(-/-) mice were more sensitive to acute arsenic toxicity and accumulated more arsenic than wild-type mice, suggesting that P-glycoproteins are involved, at least in part, in arsenic efflux in mammalians.