EPID-15. THE INTERNATIONAL DIFFUSE INTRINSIC PONTINE GLIOMA (DIPG)/DIFFUSE MIDLINE GLIOMA (DMG) REGISTRY AND REPOSITORY (IDIPGR) EXPANSION

Established in April 2012, the mission of the IDIPGR is to provide secure integrated data sets including clinical, pathologic, radiologic and molecular genomics to the research community to promote hypothesis driven research. Over 600 data points per patient are securely stored on a CCHMC constructed web resource and domain using the open-source data mart development framework Harvest (PMID:24303304) (‘Links’). Genomic data is stored in the cloud-enabled VIVA platform and accessed through cross-platform integration and standardization algorithms for comparison across datasets. Features include source identification, data wrangling, and standardization of molecular and phenotypic data (2017), a web-enabled data mart that provides phenotype-genotype query/exploration, along with raw and processed data file downloads to authorized investigators (Harvest, 2017), additional tools for filtering and analysis of genomic datasets at the level of a phenotype, sample, gene, and variant (VIVA, 2017–2018), and uploaded digitized slides (Aperio, 2019). The IDIPGR Repository stores abstracted datasets for >1020 patients with DIPG/DMG, of whom 366 have tumor tissue available through biopsy and/or autopsy, and centrally reviewed and digitized specimens from 124 patients. The Repository contains >5000 radiology studies from >700 patients, with >550 patients centrally reviewed, and genomics data from 80 patients. Currently 27 IDIPGR approved projects utilize these datasets. The DIPG/DMG Registry constructed a robust database platform and integration system that provides the infrastructure to promote highly collaborative, international, hypothesis-driven research. Broadening collaboration among investigators for hypothesis-driven research studies will lead to better classification and more effective treatment of patients with DIPG and DMG.

TEMPO® EC for the Enumeration of Escherichia coli in Foods: Collaborative Study

The automated method for enumeration of Escherichia coli, TEMPO<sup/> EC, in foods uses a dehydrated culture medium and enumeration card containing 48 wells across three different dilutions for the automatic determination of the most probable number (MPN). The alternative method was compared in a multilaboratory collaborative study to AOAC Official MethodSM 966.24. Six food types were artificially contaminated with E. coli: raw ground beef, bagged lettuce, cooked chicken, pasteurized crabmeat, frozen green beans, and pasteurized whole milk. All foods were analyzed for E. coli counts by 11 collaborating laboratories throughout the United States. Test portions from the six food types each contaminated at four different contamination levels were evaluated. The study demonstrated that the TEMPO EC method is a reliable, automated assay for the enumeration of E. coli in foods.

Evaluation of VIDAS® Listeria species Xpress (LSX) Immunoassay Method for the Detection of Listeria species in Foods: Collaborative Study

In a multilaboratory study, the effectiveness of an alternative method for rapid screening of Listeria species compared to traditional reference methods was demonstrated in a variety of food products. A collaborative study was conducted to compare the VIDAS® Listeria species Xpress (LSX) method and the standard cultural methods for the detection of Listeria species in foods. Six food types were tested: vanilla ice cream, cheddar cheese, raw ground beef, frozen green beans, deli turkey, and cooked shrimp. Each food, inoculated with a different Listeria strain at two levels and uninoculated test portions, was analyzed by each method. A total of 15 laboratories representing government and industry participated. In this study 1134 tests were analyzed in the statistical analysis. There were 490 positives by the VIDAS LSX method using the sample boiling step, 483 positives by the VIDAS LSX method using the Heat and Go system, and 439 positives by the standard culture methods. Overall, the Chi-square result for the VIDAS LSX method with boiling for all foods was 7.25, indicating a significant statistical difference between the VIDAS method and the standard methods at the 5% confidence. For the VIDAS LSX method with the Heat and Go system, the Chi-square result for all foods was 5.37, indicating a significant statistical difference between the VIDAS LSX assay with the Heat and Go system and the standard methods at the 5% level of significance. In both cases, the VIDAS method was more sensitive than the standard methods. The LSX method detects Listeria species in foods with negative or presumptive positive results in a minimum of 30 h compared to at least 5 days for the cultural methods. Based on the results of this collaborative study, it is recommended that the VIDAS LSX method be adopted as an AOAC Official MethodSM for the detection of Listeria species in dairy products, vegetables, seafood, raw meats and poultry, and processed meats and poultry.

TEMPO EC for the enumeration of Escherichia coli in foods: collaborative study

The automated method for enumeration of Escherichia coli, TEMPO EC, in foods uses a dehydrated culture medium and enumeration card containing 48 wells across three different dilutions for the automatic determination of the most probable number (MPN). The alternative method was compared in a multilaboratory collaborative study to AOAC Official Method 966.24. Six food types were artificially contaminated with E. coli: raw ground beef, bagged lettuce, cooked chicken, pasteurized crabmeat, frozen green beans, and pasteurized whole milk. All foods were analyzed for E. coli counts by 11 collaborating laboratories throughout the United States. Test portions from the six food types each contaminated at four different contamination levels were evaluated. The study demonstrated that the TEMPO EC method is a reliable, automated assay for the enumeration of E. coli in foods.

Effects of bisphosphonates APD and HEBP on bone metabolism in vitro

Although the effects of the bisphosphonates on resorption have been well documented, their effects on bone formation are not as clear. Therefore, this investigation was undertaken to elucidate the role played by bisphosphonates in the regulation of bone formation in vitro. To evaluate bisphosphonate-mediated regulation of bone formation in vitro, the effects of two drugs, ethane-1-hydroxy,1-diphosphate (Etidronate) (HEBP), and the second-generation bisphosphonate, disodium-1-hydroxy-1-aminopropylidine-1,1-diphosphate (Pamidronate) (APD), were assessed in the chick periosteal osteogenesis (CPO) model. In this study, drug-induced changes in alkaline phosphatase were assessed at the cellular level by means of quantitative fluorescence histochemistry. Cellular proliferation was quantified by means of autoradiography ([3H]thymidine). Mineralization and matrix production were measured morphometrically, whereas collagen synthesis and degradation were measured biochemically. The data suggest that in addition to their effects on bone resorption, the bisphosphonates have marked and direct effects on bone formation and other parameters of osteogenesis. HEBP may affect cellular proliferation (75-80% reduction, p < 0.05) in zones distant from bone; alkaline phosphatase positive cell numbers were increased in the osteoblastic layer of cells (twofold relative to control, p < 0.05) in 12-day cultures. HEBP, but not APD, prevented mineralization-induced suppression of matrix synthesis in early stages of culture. In 6-day cultures induced to mineralize with beta-glycerophosphate, (GP) cotreatment with HEBP induced a 70% increase in collagen synthesis. In addition, degradation of collagen in the CPO cultures was inhibited by HEBP (25%) and to a lesser extent by APD (8%). Although there were no differences in bone-osteoid areas measured in 12-day cultures treated with various regimens of bisphosphonate or GP, a clear increase in bone-osteoid area was detected in 6-day cultures treated with GP and HEBP as compared to GP only. This may suggest that initially, osteoblasts may be induced to synthesize increased volumes of bone matrix when mineralization is inhibited (e.g., with HEBP), but that over time the osteoblasts make the same amount of matrix. Taken together, these findings indicate that whereas the bisphosphonates do have well-documented effects on bone resorption, their effects on bone formation may also be important.(ABSTRACT TRUNCATED AT 400 WORDS)

Osteogenic phase-specific co-regulation of collagen synthesis and mineralization by beta-glycerophosphate in chick periosteal cultures

Mineralized bone formation in vitro can be induced by the alkaline phosphatase substrate beta-glycerophosphate (GP). GP may not only be essential for mineralization in vitro, but could also modulate other metabolic activities of bone cells, particularly if GP is presented to these cells during different phases of development. To assess GP modulation of bone cell metabolism, biochemical and autoradiographic analyses of chick periosteal cultures treated with GP were performed. About 50% less (p less than 0.05) Type I collagen was produced in periosteal cultures treated with GP. If the fibrous portion of the periostem was microdissected from the osteogenic layer prior to culture, GP inhibition of Type I collagen synthesis was even more marked (60%: p less than 0.05). To define organic phosphate-sensitive phases of osteogenesis, cultures were exposed to GP for various time periods. Mineralization occurred reproducibly when periosteal cultures were treated with GP from the outset of the incubation period (positive control). However, if GP was added after the third day of incubation, phosphate content was the same as in positive control cultures, whereas calcium content was significantly (20%: p less than 0.05) lower. Moreover, if GP was added on day 6, there was virtually no calcium accumulation by day 12, while massive amounts of phosphate had accumulated. Taken together, these findings indicate that organic phosphates may modulate phenotypic expression of osteogenic cells, and that osteogenic cells traverse an organic phosphate-sensitive phase, after which they may be incapable of normal mineralization.

Effects of bisphosphonates and inorganic pyrophosphate on osteogenesis in vitro

The bisphosphonates, which are chemically related to pyrophosphate, have been studied extensively both in vivo and in vitro to elucidate their effects on bone tissues and cells. However, because these agents have important effects on bone resorption, the majority of investigations have focused on this area. Few studies regarding direct bisphosphonate effects on bone formation have been carried out in the past and, thus, we chose to use the chick periosteal osteogenesis (CPO) in vitro model system to test the direct effects of pyrophosphate and the bisphosphonates ethane-1-hydroxy-1,1-diphosphate (HEBP) and disodium-1-hydroxy-1-amino-propylidine (APD) on various parameters of osteogenesis in vitro. The data show that the bisphosphonate HEBP inhibits bone mineralization reversibly while APD, at low doses, may actually enhance mineralization of bone. Similarly, pyrophosphate (PPi) will prevent mineralization in CPO cultures. However, CPO cultures can circumvent PPi-mediated blockage of mineralization with longer-term, continuous (10-day) incubation, whereas this does not occur if cultures are incubated continuously with bisphosphonates. Both drugs appear to be able to reverse beta-glycerophosphate-induced changes in alkaline phosphatase activity, but do not appear on their own to regulate the activity of this enzyme. The findings show that in addition to their well-known effects on resorption, bisphosphonates have significant and direct effects on mineralization in bone-forming cultures. Their direct effects on osteoblastic activity and differentiation remain to be determined.