Acid freezes uricolysis in addition to glycolysis: Utility of fluoride-EDTA-citrate tube in the measurement of uric acid for patients administered rasburicase

Background In samples from patients administered rasburicase, ex vivo uricolysis leads to spuriously low uric acid results. The manufacturer’s recommendation of storing the sample in ice-water until analysis, however, does not fully arrest uricolysis. Since uricase activity is affected by pH and metal chelators, we assessed uricolysis inhibition in sodium fluoride-ethylenediaminetetraacetic acid (EDTA)-citrate sample tube (FC Mix tube, Greiner) used primarily for plasma glucose. Method A serum pool was spiked with rasburicase and uric acid measured at 15, 45, 90, 150, 240 and 1080 min in a lithium heparin tube in ice-water, plain tube at room temperature (RT), EDTA tube at RT, FC Mix tube in ice-water, FC Mix tube at RT and FC Mix tube at RT prepared by dissolving FC Mix in serum. Results The rate of urate decay was lowest in the FC Mix tube independent of temperature, then lithium heparin tube in ice-water, then EDTA tube at RT and highest in the plain tube at RT. Uric acid concentrations in the prepared FC Mix tube at RT and heparin tube in ice-water were, respectively, 98.2% and 93.8% of control values at 90 min, 97.1% and 89.3% of control values at 4 h, and remained higher in the prepared FC Mix tube at all time points. Conclusion NaF-EDTA-citrate mixture largely arrested rasburicase mediated ex vivo uricolysis without the need for sample cooling. We propose that sample tubes containing NaF-EDTA-citrate be used for the measurement of uric acid in patients administered rasburicase.

Method to obtain PRP and L-PRP for the use in routine medical practice of orthopedic traumatologist

The paper presents the results of experimental study of two methods for blood processing to obtain platelet-rich plasma (PRP). Due to the widespread clinical use of platelet-rich plasma in orthopedics and traumatology, a differential approach to the use of PRP and leukocyte- and platelet-rich plasma (L-PRP) has become relevant. Most commercial kits for PRP preparation significantly increase the cost of treatment. In addition, the main attention is focused on the concentration of platelets in the final product and the marketing features of a particular kit (separating gel, tube shape, anticoagulant, activator, etc.). The role of leukocytes in the features of the regenerative effect of platelet-rich plasma stays out of focus. The blood of volunteers was processed in two different ways and the cellular composition of the obtained products was analyzed. Sample No. 1 was used as a control for the baseline blood cell composition. Sample No. 2 was centrifuged in a sterile plastic tube, platelet rich plasma was collected manually. Sample No. 3 was centrifuged in a sterile modified syringe, platelet rich plasma was collected using a closed technique by means of connectors together with a rich layer. The results of statistical analysis showed that there were obtained totally different biological products with different concentrations of platelets and leukocytes. The first sample (control) had platelet concentration of (228.69 ± 39.15) × 109/l and leukocyte concentration of (5.18 ± 1.32) × 109/l. In the second sample (tube + manual sampling), platelet concentration was (429.38 ± 79.92) × 109/l and leukocyte concentration — (0.85 ± 0.34) × 109/l. The third sample (syringe plunger + closed vacuum collection) had platelet concentration of (541.15 ± 85.49) × 109/l and leukocytes of (6.56 ± 1.92) × 109/l. The data are given without regard to –12.5% deviation on dilution with citrate dextrose. As the result of the work, orthopedic traumatologists can use the simplest non-commercial methods for obtaining PRP and L-PRP in their practice depending on nosology and clinical tasks.

SDS-PAGE gel electrophoresis v2

SDS-PAGE gel electrophoresis protocol for analyzing samples from plant leaf tissue via immunofluorescence. In this protocol no Coomassie blue is added to samples, the reason is that this interferes with the fluorescent signal during immunoblot. Instead, samples have already been prepared in Laemmli buffer (minus coomassie, protein extraction procedure), the leading edge of samples can be visualized due to the presence of chlorophyll. Note - When using 15 well, 0.75 mm comb, try to limit the volume loaded to 10 μL to minimize the risk of spillover of protein between wells. - Ensure that accurate volume is pipetted by removing sample stuck to the outside of the pipette tip by wiping the tip on the rim of the sample tube to remove any residual liquid. Literature: http://www.bio-rad.com/webroot/web/pdf/lsr/literature/Bulletin_6040.pdfhttps://www.bio-rad.com/webroot/web/pdf/lsr/literature/10026447.pdf

A Study on Residual Stresses on Autofrettaged LDPE Tubing Including the Bauschinger Effect and Strain Aging

This paper compares and discusses the change to the residual stresses and strains on four tubes of SA-723 Gr 1 Cl 2 (Timken HS 220) tubing material that were autofrettaged at different Overstrain ratios (20% and 40%). The four tubes were autofrettaged with strain gages to obtain actual OD strain. The effect on the residual stress and strain of the material is reviewed after a single autofrettage and after a low temperature heat treat followed by a second autofrettage. The low temperature heat treat was performed on two of the four tubes to create comparable data. Any strain aging effect from the low temperature heat treat is examined on the measured residual stress and strains. The effect and possible benefits of strain aging and re-autofrettage on tubes with different Overstrain ratios is discussed. To obtain the residual stress values in the tube wall after the autofrettage cycles, the sample tube pieces were tested by X-ray diffraction. The actual residual stresses after autofrettage were then compared with the calculated theoretical residual stresses including Bauschinger effect correction factors from ASME Section VIII Div. 3 KD-5. The residual stress and strain data between one and two rounds of autofrettage is also studied to see if the Bauschinger effect is present.

Cystatin C predicts long term mortality better than creatinine in a nationwide study of intensive care patients

Decreased glomerular filtration rate (GFR) is linked to poor survival. The predictive value of creatinine estimated GFR (eGFR) and cystatin C eGFR in critically ill patients may differ substantially, but has been less studied. This study compares long-term mortality risk prediction by eGFR using a creatinine equation (CKD-EPI), a cystatin C equation (CAPA) and a combined creatinine/cystatin C equation (CKD-EPI), in 22,488 patients treated in intensive care at three University Hospitals in Sweden, between 2004 and 2015. Patients were analysed for both creatinine and cystatin C on the same blood sample tube at admission, using accredited laboratory methods. During follow-up (median 5.1 years) 8401 (37%) patients died. Reduced eGFR was significantly associated with death by all eGFR-equations in Cox regression models. However, patients reclassified to a lower GFR-category by using the cystatin C-based equation, as compared to the creatinine-based equation, had significantly higher mortality risk compared to the referent patients not reclassified. The cystatin C equation increased C-statistics for death prediction (p < 0.001 vs. creatinine, p = 0.013 vs. combined equation). In conclusion, this data favours the sole cystatin C equation rather than the creatinine or combined equations when estimating GFR for risk prediction purposes in critically ill patients.

Development of an optimized sample preparation method for quantification of free fatty acids in food using liquid chromatography-mass spectrometry

Accurate and precise determination of free fatty acid (FFA) contents is essential for quality control and assurance in food production. Herein, a mass spectrometric study was performed to develop a sample preparation protocol that can minimize exogenous FFA contamination during the quantification of FFA in food. The quantities of exogenous FFAs were measured using various combinations of seven pretreatment methods for a sample tube, three extraction methods, and four types of sample tubes. Methanol washing could effectively reduce exogenous palmitic acid (PA) and stearic acid (SA) by 73 and 64%, respectively, in contrast to furnace baking resulting in a decrease in the amount of PA and SA contaminants by 50 and 37%, respectively. A lower amount of FFA contaminants was extracted from glass tubes during comparative analysis of the four different sample tubes studied. A combination of a methanol-washed glass tube and chloroform extraction solvent was determined to be the optimal method for minimizing the error in FFA quantification. The optimized sample preparation protocol used for FFA quantification can lower the amount of foreign palmitic acid and stearic acid to the sub-nanomolar level in the analysis of FFAs in skimmed milk.

New technique for high-precision, simultaneous measurements of CH₄, N₂O and CO₂ concentrations; isotopic and elemental ratios of N₂, O₂ and Ar; and total air content in ice cores by wet extraction

Air in polar ice cores provides unique information on past climatic and atmospheric changes. We developed a new method combining wet extraction, gas chromatography and mass spectrometry for high-precision, simultaneous measurements of eight air components (CH4, N2O and CO2 concentrations; δ15N, δ18O, δO2∕N2 and δAr∕N2; and total air content) from an ice-core sample of ∼ 60 g. The ice sample is evacuated for ∼ 2 h and melted under vacuum, and the released air is continuously transferred into a sample tube at 10 K within 10 min. The air is homogenized in the sample tube overnight at room temperature and split into two aliquots for mass spectrometric and gas chromatographic measurements. Care is taken to minimize (1) contamination of greenhouse gases by using a long evacuation time, (2) consumption of oxygen during sample storage by a passivation treatment on sample tubes, and (3) fractionation of isotopic ratios with a long homogenization time for splitting. Precision is assessed by analyzing standard gases with artificial ice and duplicate measurements of the Dome Fuji and NEEM ice cores. The overall reproducibility (1 SD) of duplicate ice-core analyses are 3.2 ppb, 2.2 ppb and 2.9 ppm for CH4, N2O and CO2 concentrations; 0.006 ‰, 0.011 ‰, 0.09 ‰ and 0.12 ‰ for δ15N, δ18O, δO2∕N2 and δAr∕N2; and 0.63 mLSTP kg−1 for total air content, respectively. Our new method successfully combines the high-precision, small-sample and multiple-species measurements, with a wide range of applications for ice-core paleoenvironmental studies.

The COVID Crisis as a Sample Tube with Contemporary Legal Phenomena

A superficial view of lawmakers’ reaction to the current pandemic crisis is that we are witnessing an aberration and a concentration of bad practices. This paper presents a partially opposite thesis that the response of legal systems to this situation is not surprising and an accumulation of several phenomena very characteristic of the contemporary evolution of law. The restriction of personal freedoms, often imposed by means far from the theoretical scope of sources of law described by demo-liberal constitutions, combined with the broad scope and curious details of the extraordinary regulations complete the general trend towards the juridisation of almost every aspect of human activities. Today, the law serves as the dominant tool of creating social and economic order, taking the fields once occupied by other (and now almost extinct) normative systems and at the same time, displacing them. Thus, the more law exists in the everyday circulation, the more demand it creates for further and even more casuistic legal regulation. In this reality, this is the only tool that can be applied in extraordinary circumstances. In addition, the applied legislative techniques are not new. The Polish act known commonly and semi-officially as the ‘anti-crisis shield’ is a typical ‘complex act’ aimed at dealing with a particular matter thoroughly through the use of all traditional methods of regulation: civilian, administrative, and penal mixed together in a single text of law. Thus, this regulation also constitutes a perfect (and perhaps the most striking) example of the phenomenon of decodification, especially in the field of private law, since it deals with particular contractual and tort issues as if there were no relevant regulations in the Civil Code, which should (at least theoretically) constitute the core of the private law system.