Machine learning identification of specific changes in myeloid cell phenotype during bloodstream infections

The early identification of bacteremia is critical for ensuring appropriate treatment of nosocomial infections in intensive care unit (ICU) patients. The aim of this study was to use flow cytometric data of myeloid cells as a biomarker of bloodstream infection (BSI). An eight-color antibody panel was used to identify seven monocyte and two dendritic cell subsets. In the learning cohort, immunophenotyping was applied to (1) control subjects, (2) postoperative heart surgery patients, as a model of noninfectious inflammatory responses, and (3) blood culture-positive patients. Of the complex changes in the myeloid cell phenotype, a decrease in myeloid and plasmacytoid dendritic cell numbers, increase in CD14(+)CD16(+) inflammatory monocyte numbers, and upregulation of neutrophils CD64 and CD123 expression were prominent in BSI patients. An extreme gradient boosting (XGBoost) algorithm called the “infection detection and ranging score” (iDAR), ranging from 0 to 100, was developed to identify infection-specific changes in 101 phenotypic variables related to neutrophils, monocytes and dendritic cells. The tenfold cross-validation achieved an area under the receiver operating characteristic (AUROC) of 0.988 (95% CI 0.985–1) for the detection of bacteremic patients. In an out-of-sample, in-house validation, iDAR achieved an AUROC of 0.85 (95% CI 0.71–0.98) in differentiating localized from bloodstream infection and 0.95 (95% CI 0.89–1) in discriminating infected from noninfected ICU patients. In conclusion, a machine learning approach was used to translate the changes in myeloid cell phenotype in response to infection into a score that could identify bacteremia with high specificity in ICU patients

Putting Aseptic Vitrification into Practice

peer reviewedVitrification is a cryopreservation strategy where cells are converted into a glass-like amorphous solid, which is free of any crystalline structure. Such process is achieved by a combination of high concentrations of cryoprotectant and an extremely high cooling rate. In the last years, survival rates of up to 80 % after thawing and pregnancy rates of almost 30 % could be achieved after transfer of vitrified embryos at the zygote, cleavage, morula and blastocyst stages. Also deliveries of healthy babies have been reported numerous times. To this day, a limited interest in this technique can be noted. The explanation may lie in the apprehension of many ART units regarding exposure of embryos to high concentrations of cryoprotectants and storage in non sterile conditions. The aim of the first part of the article is to analyse if such fears are justified due to the fact, that slow-cooling and storage of embryos based upon high aseptic conditions is presently possible. In the second part, results on survival after thawing, pregnancy-rates and baby-take-home-rates of vitrified embryos will be presented and the problems associated with vitrification of blastocysts will be discussed. J Reproduktionsmed Endokrinol 2008; 5 (3): 121–31