Deliberating Performance Targets: Follow-on workshop discussing PM10, NO2, CO, and SO2 air sensor targets.

The use of air sensor technology is increasing worldwide for a variety of applications, however, with significant variability in data quality. The United States Environmental Protection Agency held a workshop in July 2019 to deliberate possible performance targets for air sensors measuring particles with aerodynamic diameters of 10 µm or less (PM10), nitrogen dioxide (NO2), carbon monoxide (CO), and sulfur dioxide (SO2). These performance targets were discussed from the perspective of non-regulatory applications and with the sensors operating primarily in a stationary mode in outdoor environments. Attendees included representatives from multiple levels of government organizations, sensor developers, environmental nonprofits, international organizations, and academia. The workshop addressed the current lack of sensor technology requirements, discussed fit-for-purpose data quality needs, and debated transparency issues. This paper highlights the purpose and key outcomes of the workshop. While more information on performance and applications of sensors is available than in past years, the performance metrics, or parameters used to describe data quality, vary among the studies reports and there is a need for more clear and consistent approaches for evaluating sensor performance. Organizations worldwide are increasingly considering, or are in the process of developing, sensor performance targets and testing protocols. Workshop participants suggested that these new guidelines are highly desirable, would help improve data quality, and would give users more confidence in their data. Given the wide variety of uses for sensors and user backgrounds, as well as varied sensor design features (e.g., communication approaches, data tools, processing/adjustment algorithms and calibration procedures), the need for transparency was a key workshop theme. Suggestions for increasing transparency included documenting and sharing testing and performance data, detailing best practices, and sharing data processing and correction approaches.

Deliberating performance targets workshop: Potential paths for emerging PM2.5 and O3 air sensor progress.

The United States Environmental Protection Agency held an international two-day workshop in June 2018 to deliberate possible performance targets for non-regulatory fine particulate matter (PM2.5) and ozone (O3) air sensors. The need for a workshop arose from the lack of any market-wide manufacturer requirement for Ozone documented sensor performance evaluations, the lack of any independent third party or government-based sensor performance certification program, and uncertainty among all users as to the general usability of air sensor data. A multi-sector subject matter expert panel was assembled to facilitate an open discussion on these issues with multiple stakeholders. This summary provides an overview of the workshop purpose, key findings from the deliberations, and considerations for future actions specific to sensors. Important findings concerning PM2.5 and O3 sensors included the lack of consistent performance indicators and statistical metrics as well as highly variable data quality requirements depending on the intended use. While the workshop did not attempt to yield consensus on any topic, a key message was that a number of possible future actions would be beneficial to all stakeholders regarding sensor technologies. These included documentation of best practices, sharing quality assurance results along with sensor data, and the development of a common performance target lexicon, performance targets, and test protocols.

Natural atypical Listeria innocua strains with Listeria monocytogenes pathogenicity island 1 genes.

Identification of bona fide Listeria isolates into the six species of the genus normally requires only a few tests. Aberrant isolates do occur, but even then only one or two extra confirmatory tests are generally needed for identification to species level. We have discovered a hemolytic-positive, rhamnose and xylose fermentation-negative Listeria strain with surprising recalcitrance to identification to the species level due to contradictory results in standard confirmatory tests. The issue had to be resolved by using total DNA-DNA hybridization testing and then confirmed by further specific PCR-based tests including a Listeria microarray assay. The results show that this isolate is indeed a novel one. Its discovery provides the first fully documented instance of a hemolytic Listeria innocua strain. This species, by definition, is typically nonhemolytic. The L. innocua isolate contains all the members of the PrfA-regulated virulence gene cluster (Listeria pathogenicity island 1) of L. monocytogenes. It is avirulent in the mouse pathogenicity test. Avirulence is likely at least partly due to the absence of the L. monocytogenes-specific allele of iap, as well as the absence of inlA, inlB, inlC, and daaA. At least two of the virulence cluster genes, hly and plcA, which encode the L. monocytogenes hemolysin (listeriolysin O) and inositol-specific phospholipase C, respectively, are phenotypically expressed in this L. innocua strain. The detection by PCR assays of specific L. innocua genes (lin0198, lin0372, lin0419, lin0558, lin1068, lin1073, lin1074, lin2454, and lin2693) and noncoding intergenic regions (lin0454-lin0455 and nadA-lin2134) in the strain is consistent with its L. innocua DNA-DNA hybridization identity. Additional distinctly different hemolytic L. innocua strains were also studied.

Subchronic toxicity of fish oil concentrates in male and female rats.

There are an overwhelming number of reports indicating the beneficial effects of fish oil supplements in human and animal nutrition. The purpose of this study, second in a series, was to evaluate the effects, particularly those that may be harmful, of high-dose, long-term consumption of fish oil concentrates (FOC) using male and female rats. One hundred and twenty male and 120 female rats were gavaged daily with oils and oil mixtures in a volume equal to 0.5% body weight (5 mL/kg/d) for 13 weeks. The administered oils were corn oil, pure menhaden oil (MO), pure MaxEPA fish oil or different mixtures of corn oil with MO. The stability and the homogeneity of the dosing solutions were tested under study conditions. The animals received isocaloric and isonitrogenous diets throughout. Food and pure water were supplied ad libitum. At the end of the in-life phase of the study, the animals were anaesthetized with CO2 and humanely killed by exsanguination. Blood and other tissues were prepared for various clinical, histopathological and laboratory tests. Some beneficial effects of FOC, such as reduction in total serum cholesterol, in rats were confirmed. However, we also observed a significant reduction in absolute amount of serum HDL and a significant increase in relative liver and spleen weights in both sexes with the high dose of FOC. High doses of FOC (5 mL/kg/d) reduced serum iron and vitamin E concentrations. A reduction in osmotic fragility of RBC as well as an increase in RBC deformity were also observed in rats treated with high doses of FOC. These rats showed a significant overall increase in WBC count. We conclude that in rats, subchronic consumption of high levels of FOC can be beneficial but may also be harmful because of induction of clinical abnormalities including increased red cell deformity, increased relative liver and spleen weights, and reduced serum HDL, iron and vitamin E concentrations.

Feasibility of a defined microflora challenge method for evaluating the efficacy of foodborne Listeria monocytogenes selective enrichments.

Comparison of isolation methods for microbial pathogens is complicated by the variable interference caused by the competitive microflora present in test samples such as foods. In principle, using measured amounts of a standard competitor in a defined surrogate food matrix might control the effect of variable interference. This possibility was investigated using Listeria monocytogenes and enrichment broths belonging to the acriflavine-nalidixate selective agent class. Triplicate test sample sets were prepared. Each set consisted of suspensions of variable levels of the standard competitor, Enterococcus faecium strain 111 (approximately 10 to 10(9) CFU/25 g), mixed with a low constant level (10 to 100 CFU/25 g) of L. monocytogenes. These test samples were enriched at 30 degrees C for 48 h in different selective media and streaked onto selective isolation agars. The input CFU ratio (E. faecium/L. monocytogenes) that permitted a 50% end point L. monocytogenes recovery was 2.2 x 10(6) or higher for the Food and Drug Administration one-step enrichments and 0.8 x 10(6) for the International Standards Organization (ISO) two-step enrichment. These and other results show that this evaluation method is feasible with this class of enrichments. Interestingly, L. monocytogenes could be detected in enrichment cultures at high-input E. faecium/L. monocytogenes ratios even when the enriched samples were plated onto nonselective media. The pinpoint colonies of L. monocytogenes embedded in a confluent lawn of E. faecium 111 were detectable by their contrasting coloration in Henry obliquely transmitted illumination.

Design of "High 5": a school-based study to promote fruit and vegetable consumption for reduction of cancer risk.

BACKGROUND: This paper describes the methods used in "High 5," a school-based study to increase fruit and vegetable consumption for cancer risk reduction. METHODS: Twenty-eight elementary schools were matched and randomized to intervention or control conditions. All students were assessed based on diet and psychosocial variables at baseline and one and two years post-baseline. The intervention included classroom, parent, and environmental components. RESULTS: The study recruited 1,698 families and retained 85%. The two conditions were equivalent at baseline; 50% female students, 81% to 84% European-American students, and 2.9 servings of fruit and vegetables per day. Good completion was achieved across the intervention components (e.g., 90% of lessons taught, 72% of parent materials read, 3.6 servings of fruit and vegetables offered in cafeterias). CONCLUSIONS: The use of school-based programs, with strong evaluation designs, will enhance knowledge about the modification of nutrition behavior and cancer risk in children. Lessons learned from the study are reported.

Heparin versus citrate regional anticoagulation during autotransfusion in a porcine intra-abdominal hemorrhage model.

Our objective was to determine the effects of anticoagulants and blood loss on hemodynamic, hematologic, and coagulation parameters following autotransfusion in an animal model of intraabdominal hemorrhage. We performed a prospective, randomized observational animal study at an animal research laboratory at a university medical center. Eight Landrace, domestic pigs, weighing 17-23 kg, each underwent jugular venous and iliac arterial catheterization and laparotomy with retroperitoneal dissection for aortic exposure to simulate an operative environment. Following baseline laboratory and hemodynamic determinations, intra-abdominal hemorrhage was accomplished via aortotomy in three sequential 10 mL/kg blood volumes. After allowing pooling in the exposed retroperitoneum to ensure tissue contact, the shed blood was suctioned, processed, and washed in an autotransfusion device utilizing either heparin (n = 4) or acid-citrate-dextrose (n = 4) as a system anticoagulant. Prior to autologous transfusion, each pig received a 20 mL/kg intravenous bolus of 0.9 per cent saline to treat shock. The processed blood was then infused, and laboratory and hemodynamic measurements were repeated following each cycle of hemorrhage and autotransfusion. Sequential fixed volume hemorrhage resulted in significant reductions in mean arterial pressure. Despite crystalloid infusion and transfusion of processed shed blood, postresuscitation mean arterial pressure did not return to baseline values, with no difference noted between anticoagulant groups. Infusion of increasing volumes of autologous blood resulted in significant reductions in hematocrit, platelet count, fibrinogen, antithrombin III, ionized calcium, and total protein. The decrease in concentration of each variable was independent of the choice of anticoagulant with the exception of antithrombin III, with higher levels noted in animals receiving blood anticoagulated with acid-citrate-dextrose. Prothrombin time and partial thromboplastin time were unaffected by volume of autologous transfusion or choice of anticoagulant. We conclude that changes in hemodynamic, hematologic, and coagulation parameters associated with hemorrhage and autotransfusion appear related more to the volume of blood loss and the cumulative pheresis of plasma than to the choice of anticoagulant.

Recruitment issues in school-based research: lessons learned from the High 5 Alabama Project.

School-based research requires a multi-level recruitment process to ensure an adequate sample. This article describes the High 5 Alabama recruitment experience at four levels; district, school, classroom and individual. One hundred percent of 28 schools across three districts and 108 classroom teachers contacted agreed to participate. Moderate success (69%) at the individual level, which required active parental consent for the student and parent to participate, resulted in 1,698 student/parent participants. An examination of differences between participants and nonparticipants revealed under-representation of a subsample of the population in the project sample. Suggestions obtained from project staff and teachers intended to enhance future school-based recruitment strategies include enlistment of a district advocate; meeting with teachers to solicit support; using incentives with students and teachers; direct contact with parents; having teachers keep rosters of students returning consent forms; and tailoring recruitment strategies for specific subpopulations.

Effects of intraluminal and extracorporeal inferior vena caval bypass on canine hemodynamics.

OBJECTIVE: To compare inferior vena cava-right atrial extracorporeal bypass with intraluminal atriocaval shunting during hepatic vascular isolation. DESIGN: Prospective, randomized, controlled animal study. SETTING: University research laboratory. SUBJECTS: Adult mongrel dogs (n = 5) weighing 20 to 27 kg. INTERVENTIONS: Anesthetized dogs underwent laparotomy and sternotomy for vascular isolation. For atriocaval shunting, 20- and 24-Fr intraluminal shunts were inserted into the inferior vena cava via right atriotomy. For extracorporeal bypass, each animal underwent inferior vena cava, portal vein, and right atrial cannulation for venovenous bypass, utilizing a centrifugal pump. Hemodynamic data were recorded at baseline and at intervals after caval occlusion, Pringle maneuver, and caval occlusion with Pringle maneuver. MEASUREMENTS AND MAIN RESULTS: Isolated Pringle maneuver and caval occlusion with Pringle maneuver produced significant reductions in mean arterial pressure (MAP) and cardiac output, irrespective of pulmonary artery occlusion pressure. Extracorporeal bypass, including both caval and portal venous return, produced significant increases in MAP and cardiac output during caval occlusion with Pringle maneuver, while atriocaval shunting and extracorporeal bypass without portal venous return did not improve MAP or cardiac output. CONCLUSION: Venovenous extracorporeal bypass with portal return, acting as a right ventricular assist device, is superior to intraluminal atriocaval shunting in maintaining hemodynamic stability during hepatic vascular isolation.

Reversal of advanced liver fibrosis in rabbits with Schistosomiasis japonica.

Advanced liver fibrosis is generally considered to be irreversible. We studied the reversibility of marked liver fibrosis in rabbits infected with Schistosoma japonicum. We determined liver collagen content, collagen biosynthesis, and collagenase activity using serial biopsy specimens obtained 20, 40, and 60 weeks after infection. Reversibility of this process was investigated in rabbits cured of infection at 21 weeks; control rabbits not cured of infection were also studied. At 20 weeks, liver collagen content was 16-fold greater than normal, with accumulation of collagen types I, III, and V. Synthesis of collagen within fibrotic liver slices was 10-fold greater than normal. Liver collagenolytic activity for a type I substrate was 19-fold greater than normal. After parasitologic cure, a striking morphologic reversal of fibrosis occurred during the subsequent 40 weeks, with the return of liver collagen content to three-fold greater than normal and a 75% decrease in synthetic rates compared with those at 20 weeks (P < 0.01). Collagenolytic activity remained elevated to the same degree noted at 20 weeks. A similar but lesser resolution of fibrosis also occurred in untreated control rabbits, coincident with a spontaneous decrease in new egg deposition known to occur in this model system. We conclude that advanced liver fibrosis in S. japonicum-infected rabbits is slowly reversible after cure or senescence of the infection. A possible mechanism for this reversal is persistently increased collagenolysis as collagen synthesis diminishes.

Natural history of Schistosoma mansoni infection in mice: egg production, egg passage in the feces, and contribution of host and parasite death to changes in worm numbers.

Mice, C57Bl/6N (B6) and BALB/cAnN (BALB), infected with Schistosoma mansoni were examined 8-26 weeks postinfection (PI) to estimate the fecundity of the worms and the contribution of death of worms and the death of heavily infected mice to the decrease in worm numbers in chronic infections. Portal worms were recovered by perfusion and the lungs were examined for parasites shunted from the portal circulation. Animals that died were more heavily infected than those that survived. Between eight and 12 weeks PI, this loss of worms resulted in a net decrease of approximately 19% of worm pairs in surviving BALB mice, but of only 4% in B6 mice. Loss of portal worms to the lungs after the eighth week of infection was 9-13% of portal worms in BALB mice and 3-4% in B6 mice. The estimated rates of egg production by S. mansoni decreased slightly with time in both strains of mice. At 12 and 20 weeks PI, tissue eggs per worm pair and eggs passed in the feces per worm pair often decreased as the intensity of infection increased. We do not consider the loss of worms in the murine host relevant to most infections in humans because of the high intensity of infection relative to body size in mice and the high frequency of severe portal obstruction in murine infections.

Evaluation of a rapid method for measuring theophylline in a clinical setting.

The need to determine rapidly the theophylline levels of patients in ambulatory settings such as family practice offices has led to the development of instruments purported to be fast, reliable, and cost-effective. This study evaluated one such instrument, the Ames Seralyzer, and compared the findings with those of the Du Pont aca. Forty-six patient samples were split and run on both instruments by trained laboratory personnel. Validation studies yielded a correlation coefficient of r = .9680 (N = 46). Precision assays showed the 27.5 and 82.5 mumol/L (5 and 15 mg/L) levels of theophylline found in control samples produced day-to-day coefficients of variation of 8.8% (n = 43) and 5.8% (n = 35), respectively. After initial evaluation of the Seralyzer, duplicate assays were performed because of erratic results. The evaluators felt that a major source of error was in the diluting and pipetting steps involved in the procedure. The Seralyzer was easy to run but did require some technique-dependent skills.

Granuloma formation in Schistosoma japonicum infected nude mice: the effects of reconstitution with L3T4+ or Lyt2+ splenic cells.

The role of L3T4+ and Lyt2+ lymphocytes in the formation and modulation of granulomas around Schistosoma japonicum eggs was examined in athymic mice. Nude C57BL/6 mice infected with S. japonicum miracidia were compared to nude mice given normal spleen cells depleted of L3T4+ or Lyt2+ cells prior to infection and to intact mice. Nude mice formed small granulomas that were poor in eosinophils and connective tissue. Nude mice reconstituted with cells enriched for L3T4+ or Lyt2+ cells formed granulomas similar in size to those in intact mice, but granulomas in mice given Lyt2+ cells contained few eosinophils and had significantly less collagen than did granulomas in mice given L3T4+ cells. The same was true at 10 weeks. Mice reconstituted with null cells were examined at 7 weeks and formed granulomas similar to those in mice given Lyt2+ cells. By 10 weeks after infection, granulomas had decreased to the same minute size in all groups of mice. Fibrosis increased at weeks 7-10 in all groups of mice.

Resistance of capuchin monkeys to reinfection with Schistosoma haematobium.

Capuchin monkeys were resistant to reinfection with Schistosoma haematobium one year after exposure to 500 cercariae, but worms in these monkeys continued to produce normal numbers of eggs. Monkeys were apparently completely refractory to reinfection when challenged 2-5 years after an initial exposure of 1000 to 2000 cercariae.

Variable maturation and oviposition by female Schistosoma japonicum in mice: the effects of irradiation of the host prior to infection.

The maturation of female Schistosoma japonicum was found to vary greatly within each of two Philippine strains of this parasite and some females did not contain uterine eggs 7 to 15 weeks after infection while others contained numerous eggs before the fifth week of infection. It was found that female worms containing less than 20 uterine eggs contributed little to the accumulation of eggs in the tissues of infected mice. Such worms also generally appeared to be immature. The variable rate of maturation of worms is likely to have profound effects on the immune reactions of mice as well as on the pathologic response to infection. Systematic delay in oviposition was serendipitously found in worms from mice which had been irradiated for other purposes prior to exposure to S. japonicum, and from the fourth to the sixth week after infection egg production by worms in irradiated mice lagged well behind that in intact mice. Seven to 10 weeks after infection these worms were laying normal numbers of eggs, as judged by egg passage per worm pair in the feces and the accumulation of eggs in the tissues. S. mansoni developed normally in irradiated mice.

Variation of hepatic fibrosis and granuloma size among mouse strains infected with Schistosoma mansoni.

To investigate the relation between the size of circumoval granulomas and hepatic fibrosis, a variety of mouse strains infected with Schistosoma mansoni were examined and the number of eggs in the tissues, the fibrotic responses to the eggs, and the volume of the granulomas were determined. Marked differences in granuloma volume and in hepatic fibrosis were found between mouse strains, and those strains with the largest granulomas also showed the most hepatic fibrosis. On the other hand no significant correlation between granuloma size and hepatic fibrosis was found in the progeny of the F2 generation and backcrosses between F1 mice and the parental strains when crosses were made between Nmri mice (high granuloma volume and high fibrosis) and C57BL/6 mice (low granuloma volume and low fibrosis). Hepatic fibrosis per egg decreased with increasing infection intensity while granuloma volume was unaffected, indicating that fibrosis and granuloma size are at least in part modulated by different factors. The number of eggs found in the tissues per worm pair and the proportion of eggs in the liver also decreased as infection intensity increased. Some influence of the major histocompatibility complex on both granuloma size and fibrosis was found. Congenic mice on the C57BL/10 and C3H/HeSn backgrounds showed larger granulomas in H-2b than in H-2k mice, but no such correlation was found in comparing C57BL/6 mice with B6.H-2k mice. Less hepatic fibrosis was found in B10.M (H-2f), B10.SM (H-2v), and B10.RIII (H-2r) animals than in C57BL/10 mice. The regulation of granuloma size and of hepatic fibrosis is clearly complex and involves genes both outside of and within the major histocompatibility complex.

Differences in hepatic fibrosis and granuloma size in several strains of mice infected with Schistosoma japonicum.

Mice of several strains were exposed to Schistosoma japonicum cercariae and killed 6, 7, 10, or 15 weeks later. Hepatic fibrosis was consistently most marked in ICR mice and least marked in C57BL/6, A and C57BL/Ks mice. Intermediate degrees of fibrosis were present in C3H, CBA and Nmri mice. The size of circumoval granulomas also varied greatly among mouse strains but the degree of hepatic fibrosis was unrelated to granuloma size, indicating that the mechanisms regulating granuloma size may not be relevant to other important parameters of pathology induced by schistosome infection. The degree of fibrosis in S. japonicum-infected ICR mice is similar to that measured in S. japonicum-infected rabbits but is less than that in S. mansoni-infected mice.

Differences in hepatic fibrosis in ICR, C3H, and C57BL/6 mice infected with Schistosoma mansoni.

The collagen content of the liver, measured as hepatic hydroxyproline, was examined for a period of up to 52 weeks following Schistosoma mansoni infection. Hepatic fibrosis was much more marked in S. mansoni-infected mice of an outbred ICR strain than in C57BL/6J mice, while C3H/HeN mice occupied an intermediate position. The marked difference in hepatic fibrosis in ICR and C57BL/6J mice correlated with more rapid in vitro synthesis of collagen by the livers of infected ICR mice. Strains of mice exhibiting high and low levels of fibrosis provide an excellent tool for examining mechanisms of murine schistosomal hepatic fibrosis and its genetic regulation.

Hepatic fibrosis in Schistosoma haematobium-infected mice.

Swiss mice were exposed subcutaneously to 270 to 500 Schistosoma haematobium cercariae and killed 13 to 52 weeks later. Less than 10% of applied cercariae were recovered as worms, and the rate of oviposition by adult worm pairs was generally low. However, the adult worms survived well, the females contained an average of 56 eggs one year after infection, and numerous mature eggs were present in the tissues. All worms were located in the portal venous system. S. haematobium eggs in the liver elicited marked fibrosis, comparable to the fibrosis induced by S. mansoni infection. Only minimal fibrosis is seen around S. haematobium eggs in the liver of numerous other species, including man, the chimpanzee, other non-human primates and hamsters. Our findings illustrate the diverse relationships often seen between a single schistosome species and its mammalian hosts and emphasize the uncertainty in predicting the outcome of human schistosome infections from the study of experimental hosts.