Robust estimation of bacterial cell count from optical density

Optical density (OD) is widely used to estimate the density of cells in liquid culture, but cannot be compared between instruments without a standardized calibration protocol and is challenging to relate to actual cell count. We address this with an interlaboratory study comparing three simple, low-cost, and highly accessible OD calibration protocols across 244 laboratories, applied to eight strains of constitutive GFP-expressing E. coli. Based on our results, we recommend calibrating OD to estimated cell count using serial dilution of silica microspheres, which produces highly precise calibration (95.5% of residuals <1.2-fold), is easily assessed for quality control, also assesses instrument effective linear range, and can be combined with fluorescence calibration to obtain units of Molecules of Equivalent Fluorescein (MEFL) per cell, allowing direct comparison and data fusion with flow cytometry measurements: in our study, fluorescence per cell measurements showed only a 1.07-fold mean difference between plate reader and flow cytometry data

Diagnostic concordance between traditional and digital workflows. A study on 1427 prostate biopsies

Objective: To evaluate intra-observer diagnostic reproducibility using traditional slides (TS) versus whole slide images (WSI). Methods: TS and WSI of 1427 prostatic biopsies (107 consecutive patients) were evaluated by a single pathologist. Agreement between readings was evaluated with Gwet's Agreement coefficient (AC) and Landis and Koch benchmark scale. Results: The positive/negative agreement between the readings was almost perfect (AC1= 0.962; 95% CI[0.949,0.974]), with method independent distribution of discrepancies. Among positive biopsies, 212 had identical Gleason score (GS) on TS and WSI and discordant GS in 69 cases (AC2 = 0.932; 95% CI[0.907, 0.956]). Concordant negative and positive patient classification was observed in 39 and 64 cases, respectively; two cases were assigned to the positive group on TS and 2 on WSI configuring an almost perfect agreement (AC1=0.929; 95% C1[0.860, 0.998]). ISUP Grade group (ISUP GG) agreement was evaluated in the 60 concordantly positive cases: in 45 cases it was identical on TS and WSI; in 10 biopsies the discrepancy implied a modification of the assigned ISUP GG of ≤ 1 class and in 5 the discrepancy implied a modification of 2 classes. Gwet's agreement coefficient was (95% CI [0.834, 0.962]), i.e.: almost perfect agreement. Conclusions: Our data show almost perfect agreement between digital and traditional diagnostic activity in a routine setting, confirming that digital pathology can be safely introduced into routine workflows

Maintaining the gluten-free diet: The key to improve glycemic metrics in youths with type 1 diabetes and celiac disease

Aims: Gluten-free diets (GFD) were considered as high glycemic index and/or high content of saturated fats; this could affect keeping good metabolic control in individuals with both type 1 diabetes (T1D) and celiac disease (CD). Our objective was to analyze time in range and other continuous glucose monitoring (CGM) metrics with real-time CGM systems, in youths with T1D and CD, compared to those with T1D only. Methods: An observational case-control study, comparing youths aged 8-18 years with T1D and CD, with people with T1D only was performed. The degree of maintaining GFD was assessed through anti-tissue transglutaminase antibodies and dietary interview, and maintaining Mediterranean diet through the KIDMED questionnaire. Results: 86 youths with T1D and CD, 167 controls with T1D only, were included in the study and the two groups reported similar real-time CGM metrics. Among the first group, 29 % were not completely maintaining GFD and compared to people with T1D only they showed higher hyperglycemia rates (% time above range: 38.72 ± 20.94 vs 34.34 ± 20.94; P = 0.039). Conclusions: Individuals with T1D and CD who maintain GFD presented similar glucose metrics compared to youths with T1D only. Individuals not strictly maintaining GFD presented higher hyperglycemia rates