Ophthalmic manifestations are associated with reduced tear lymphotoxin-α levels in chronic ocular graft-versus-host disease

Purpose To determine the role tear lymphotoxin-α (LT-α) in chronic ocular graft-versus-host disease (oGVHD). Methods Twenty-two chronic oGVHD and 17 control tear samples were collected, and commercial test strips were used to detect LT-α concentrations. Concentration differences between patients with and without oGVHD were determined via Mann-Whitney U test. The correlation between LT-α levels and ophthalmic parameters was analyzed using Spearman’s test. Results The concentration of LT-α was significantly lower in oGVHD patients than in controls. LT-α levels were significantly correlated with OSDI, NIH eye score, T-BUT, and CFS among all participants. ROC analysis revealed that the area under the curve of LT-α was 0.847, and the cutoff value for chronic oGVHD diagnosis was 0.203 ng/mL. Conclusion Our study revealed the significant decrease of tear LT-α in oGVHD, and suggested LT-α as a promising marker for chronic oGVHD diagnosis.

Fluorescent probe for the detection of hypochlorous acid in water samples and cell models

A new fluorescence probe was successfully applied to test strips and imaging analysis of exogenous and endogenous hypochlorite in living cells.

Indole as a new tentative marker in exhaled breath for non-invasive blood glucose monitoring of diabetic subjects

Blood glucose monitoring (BGM) is the most important part of diabetes management. In classical BGM, glucose measurement by test strips involves invasive finger pricking. We present results of a clinical study that focused on a non-invasive approach based on volatile organic compounds (VOCs) in exhaled breath. Main objective was the discovery of markers for prediction of blood glucose levels (BGL) in diabetic patients. Exhaled breath was measured repeatedly in 60 diabetic patients (30 type 1, 30 type 2) in fasting state and after a standardized meal. Proton Transfer Reaction Time of Flight Mass Spectrometry (PTR-ToF-MS) was used to sample breath every 15 minutes for a total of six hours. BGLs were tested in parallel via BGM test strips. VOC signals were plotted against glucose trends for each subject to identify correlations. Exhaled indole (a bacterial metabolite of tryptophan) showed significant mean correlation to BGL (with negative trend) and significant individual correlation in 36 patients. The type of diabetes did not affect this result. Additional experiments of one healthy male subject by ingestion of lactulose and 13C-labeled glucose (n=3) revealed that exhaled indole does not directly originate from food digestion by intestinal microbiota. As indole has been linked to human glucose metabolism, it might be a tentative marker in breath for non-invasive BGM. Clinical studies with greater diversity are required for confirmation of such results and further investigation of metabolic pathways.

Klebsiella pneumoniae and Colistin Susceptibility Testing: Performance Evaluation for Broth Microdilution, Agar Dilution and Minimum Inhibitory Concentration Test Strips and Impact of the “Skipped Well” Phenomenon

The emergence of multidrug resistant Gram-negative pathogens, particularly carbapenemase producers, has forced clinicians to use last line antibiotics, such as colistin. Since colistin susceptibility testing presents several challenges, this study aimed at evaluating the performance of two alternative susceptibility methods for Klebsiella pneumoniae, namely, agar dilution (AD) and MIC test strips (MTS). These approaches were compared with the reference method, broth microdilution (BMD), and provide a quantitative description for the “skipped well” (SW) phenomenon. Colistin susceptibility was evaluated by BMD and AD in parallel and triplicate, using 141 K. pneumoniae clinical isolates while MTS performance was evaluated only for a subset (n = 121). Minimum inhibitory concentration analysis revealed that a substantial part (n = 26/141; 18.4%) of the initial isolates was deemed undetermined by BMD due to the following: discordance between replicates (1.4%); presence of multiple SWs (7.8%); and the combination of both events (9.2%). Both AD and MTS revealed a high number of false-susceptible strains (“very major errors”), 37.5% and 68.8%, respectively. However, AD agreement indices were reasonably high (EA = 71.3% and CA = 94.8%). For MTS these indices were lower, in particular EA (EA = 41.7% and CA = 89.6), but the approach enabled the detection of distinct sub-populations for four isolates. In conclusion, this study provides the most comprehensive study on the performance of AD and MTS for colistin susceptibility testing in K. pneumoniae, highlighting its limitations, and stressing the importance of sample size and composition. Further, this study highlights the impact of the SW phenomenon associated with the BMD method for K. pneumoniae.

Application of Accu-Chek® Test Strips as inexpensive microelectrodes for BIA research

In the midst of an investigation to perform bioelectrical impedance analysis (BIA), we were faced with the need to search for optimally adjusted electrodes to perform reading in small biological samples. The best option to carry out these readings is the well-known gold microelectrodes; however, these are very expensive for our research purposes. For this reason, we found an alternative using Accu-Chek Performa test strips as reading microelectrodes due to their low cost and ease of disposal. This article contains an in-depth detail of the components of the Accu-Chek Performa test strip and the process that was used so that they could be suitable for taking measurements on biological material. In addition, a measurement scheme is shown in conclusion to the operation of the test strip as a microelectrode and the possible problems to consider if it is to be used for future research.