In vivo measurements of prelamina and lamina cribrosa biomechanical properties in humans

Purpose: To develop and use a custom virtual fields method (VFM) to assess the biomechanical properties of human prelamina and lamina cribrosa (LC) in vivo. Methods: Clinical data of 20 healthy, 20 ocular hypertensive (OHT), 20 primary open-angle glaucoma, and 16 primary angle-closure glaucoma eyes were analyzed. For each eye, the intraocular pressure (IOP) and optical coherence tomography (OCT) images of the optic nerve head (ONH) were acquired at the normal state and after acute IOP elevation. The IOP-induced deformation of the ONH was obtained from the OCT volumes using a three-dimensional tracking algorithm and fed into the VFM to extract the biomechanical properties of the prelamina and the LC in vivo. Statistical measurements and P values from the Mann-Whitney-Wilcoxon tests were reported. Results: The average shear moduli of the prelamina and the LC were 64.2 ± 36.1 kPa and 73.1 ± 46.9 kPa, respectively. The shear moduli of the prelamina of healthy subjects were significantly lower than those of the OHT subjects. Comparisons between healthy and glaucoma subjects could not be made robustly due to a small sample size. Conclusions: We have developed a methodology to assess the biomechanical properties of human ONH tissues in vivo and provide preliminary comparisons in healthy and OHT subjects. Our proposed methodology may be of interest for glaucoma management

Purification of urine samples to improve detection limit of anabolic agents

Objective: To investigate recovery percentage of clenbuterol, nandrolone, stanozolol, and epimetendiol by two different solid phase extraction procedures viz. XAD2 (polystyrene divinylbenzene) and SPE columns (C18, Samprep, Rankem) so as to improve detection limit of anabolic steroids. Materials and Methods: The urine samples were spiked with different concentrations of drugs. The preliminary work was done with six samples, each of clenbuterol, nandrolone, and epimetendiol at 1, 2, 5, and 10 ng/mL and of stanozolol at 5,10, 20, and 40 ng/mL that were processed and injected into high resolution mass spectrometer. Later the study was limited to clenbuterol and epimetendiol at 2, 5, and 10 ng/mL concentrations. The data were analysed by comparing XAD2 and SPE column values. Results: The results show that the recovery percentage of nandrolone and stanozolol at various concentrations did not signify any difference between the two columns. However, there was a significant increase in the recovery of clenbuterol at 2 ng/mL ( P < 0.002), 5 ng/mL ( P < 0.001), and 10 ng/mL ( P < 0.001) concentrations, where as for epimetendiol there was significant increase in the recovery at 2, 5, and 10 ng/mL ( P < 0.01) with SPE column compared to XAD2 column. Conclusion: It is possible to enhance the detection limit of clenbuterol and epimetendiol by SPE column compared to XAD2 column. This procedure may be used for confirmation of suspicious samples found in routine testing

Sample purification procedure for confirmation of 3′-hydroxy stanozolol by gas chromatography/high resolution mass spectrometry

Objective: To improve the detection limit of 3′-hydroxy-stanozolol by using the double extraction procedure, specific for basic drugs. Materials and Methods: The urine samples were spiked in four replicates with 3′-hydroxy-stanozolol at different concentrations of 1, 2, 5 and 10 ng/mL, processed by two different methods and injected into gas chromatography/high resolution mass spectrometry (GC-HRMS) instrument. The data was analyzed by comparing the recovery values and the ion match criterion of the two procedures. Results: The results show that the recovery percentage and ion match criterion of 3′-hydroxy-stanozolol at lower concentrations has a significant improvement when Solid phase extraction was performed, instead of Liquid-liquid extraction in the second extraction procedure. Conclusion: The sample preparation procedure using Oasis-MCX cartridges allows confirmation of 3′-hydroxy-stanozolol at the minimum required performance limit (MRPL) decided by the World Anti Doping Agency. This procedure may be used for the confirmation of suspicious samples found in routine testing, as it efficiently fulfills the ion-matching criterion laid down by the World Anti Doping Agency

Nandrolone criteria for 19-norandrosterone Isotope Ratio Mass Spectrometric confirmation

The detection of the use of nandrolone and other 19-norsteroids is based primarily upon the identification of the main urinary metabolite, 19-norandrosterone (19-NA) in a concentration (derived from hydrolysis with β-glucuronidase) greater than the Decision Limit (DL), as established in the DL Technical Document. The presence of 19-NA in urine samples can be originated by in-vivo endogenous production (ovulation or pregnancy in females) and/or exogenous administrations (nandrolone or nandrolone precursors) or by ex-vivo production in urine by in-situ 19-demethylation of androsterone (A) (active urines)

Untargeted Metabolomics Identifies a Novel Panel of Markers for Autologous Blood Transfusion

Untargeted metabolomics was used to analyze serum and urine samples for biomarkers of autologous blood transfusion (ABT). Red blood cell concentrates from donated blood were stored for 35&ndash;36 days prior to reinfusion into the donors. Participants were sampled at different time points post-donation and up to 7 days post-transfusion. Metabolomic profiling was performed using ACQUITY ultra performance liquid chromatography (UPLC), Q-Exactive high resolution/accurate mass spectrometer interfaced with a heated electrospray ionization (HESI-II) source and Orbitrap mass analyzer operated at 35,000 mass resolution. The markers of ABT were determined by principal component analysis and metabolites that had p &lt; 0.05 and met &ge; 2-fold change from baseline were selected. A total of 11 serum and eight urinary metabolites, including two urinary plasticizer metabolites, were altered during the study. By the seventh day post-transfusion, the plasticizers had returned to baseline, while changes in nine other metabolites (seven serum and two urinary) remained. Five of these metabolites (serum inosine, guanosine and sphinganine and urinary isocitrate and erythronate) were upregulated, while serum glycourdeoxycholate, S-allylcysteine, 17-alphahydroxypregnenalone 3 and Glutamine conjugate of C6H10O2 (2)* were downregulated. This is the first study to identify a panel of metabolites, from serum and urine, as markers of ABT. Once independently validated, it could be universally adopted to detect ABT

Spectrally encoded extended source optical coherence tomography

We have developed an extended source optical coherence tomography (SEES-OCT) technique in an attempt to improve signal strength for ophthalmic imaging. A line illumination with a visual angle of 7.9 mrad is produced by introducing a dispersive element in the infinity space of the sample arm. The maximum permissible exposure (MPE) of such an extended source is 3.1 times larger than that of a ‘standard’ point source OCT, which corresponds to sensitivity improvement of 5-dB. The advantage of SEES-OCT in providing superior penetration depth over a point source system is demonstrated using swine eye tissues ex vivo.NMRC (Natl Medical Research Council, S’pore)Accepted versio

Untargeted Metabolomics Identifies a Novel Panel of Markers for Autologous Blood Transfusion

Untargeted metabolomics was used to analyze serum and urine samples for biomarkers of autologous blood transfusion (ABT). Red blood cell concentrates from donated blood were stored for 35&ndash;36 days prior to reinfusion into the donors. Participants were sampled at different time points post-donation and up to 7 days post-transfusion. Metabolomic profiling was performed using ACQUITY ultra performance liquid chromatography (UPLC), Q-Exactive high resolution/accurate mass spectrometer interfaced with a heated electrospray ionization (HESI-II) source and Orbitrap mass analyzer operated at 35,000 mass resolution. The markers of ABT were determined by principal component analysis and metabolites that had p &lt; 0.05 and met &ge; 2-fold change from baseline were selected. A total of 11 serum and eight urinary metabolites, including two urinary plasticizer metabolites, were altered during the study. By the seventh day post-transfusion, the plasticizers had returned to baseline, while changes in nine other metabolites (seven serum and two urinary) remained. Five of these metabolites (serum inosine, guanosine and sphinganine and urinary isocitrate and erythronate) were upregulated, while serum glycourdeoxycholate, S-allylcysteine, 17-alphahydroxypregnenalone 3 and Glutamine conjugate of C6H10O2 (2)* were downregulated. This is the first study to identify a panel of metabolites, from serum and urine, as markers of ABT. Once independently validated, it could be universally adopted to detect ABT