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Biopsy Processing Protocol
Published in Maher Kurdi, Neuromuscular Pathology Made Easy, 2021
The selected frozen fragment is prepared for cross sectioning in a cryostat machine. Loose ends are trimmed to make the fragment as square as possible for sectioning. To embed the muscle, Tragacanth gum is used. The Tragacanth gum is applied to the Teflon block where the muscle fragment is anchored slightly to it (Figure 6.1b). The Teflon block serves as a place to secure the muscle fragment and also to provide a solid rigid medium to manipulate it for the flash freezing process.
Homicide
Published in Burkhard Madea, Asphyxiation, Suffocation,and Neck Pressure Deaths, 2020
Burkhard Madea, Musshoff Frank, Schmidt Peter
Recently, we have investigated the pharmacokinetic properties of SMC in surgical patients receiving 80–100 mg SUX via bolus injection [111]. SMC peak plasma concentrations were observed 0.03–2.0 minutes after application. In contrast to SUX, SMC was more slowly and more extensively distributed, featuring triphasic plasma concentration time profiles. With a terminal half-life of 1–3 hours, the window of detection for SMC in plasma was approximately 8–24 hours. However, this study used optimized sampling conditions (prompt sampling, instant stabilization, flash freezing), whereas less ideal conditions have to be expected in real forensic settings. Esterase activity on both SUX and SMC continues in vitro and especially postmortem and may lead to complete elimination of both analytes in blood and tissues. Especially in postmortem cases, more or less esterase-free urine seems to be the specimen of choice for the proof of an antemortem SUX application [106]. In tissue samples, caution must be taken regarding the possibility of false-positive SMC findings from interferences in the main ion transition [106,117,122,143]. Such interferences were excluded in the case presented.
Assisted reproduction
Published in David M. Luesley, Mark D. Kilby, Obstetrics & Gynaecology, 2016
Women having surplus embryos can opt for embryo freezing after appropriate HFEA consents from both partners. Embryos can be frozen at the fertilisation stage, cleavage stage (Day 2/3) or at the blastocyst stage (Day 5/6). Embryo thaw survival rates are better when they are frozen at earlier stages of development. With advancement in vitrification or ‘flash freezing’ process, better survival rates are observed. Women who suffer complications following oocyte retrieval, those with suboptimal endometrial quality or those at higher risk for OHSS should have their embryos frozen and should proceed with FET at a later date. They should be counselled about a small chance of a failed thawing process. Embryo cryopreservation is also undertaken to preserve fertility when one partner (in a stable relationship) is diagnosed with a significant medical condition or malignancy which may impact on their future fertility potential (Chapter 92).
Metabolomics in antimicrobial drug discovery
Published in Expert Opinion on Drug Discovery, 2022
Metabolomic analyses are essentially consisted of sample preparation, separation, and detection. Once a sample is collected, all metabolic reactions should be extinguished in order to have a snapshot of all metabolites present at a given time and conditions. Samples can be preserved by flash freezing in liquid nitrogen, freezing on dry ice, or adding organic solvents. The latter could be considered as a part of the extraction step, which is aimed at collection of as many metabolites as possible, while trying to preserve their chemical structure. This is usually accomplished by solid-phase or liquid–liquid extraction, where the compounds of interest are placed in a liquid mixture, which allows their separation from other compounds, thus concentrating the sample and removing impurities that may interfere with further analyses [3].
Dosimetry in vitro – exploring the sensitivity of deposited dose predictions vs. affinity, polydispersity, freeze-thawing, and analytical methods
Published in Nanotoxicology, 2021
Johannes G. Keller, Daniel F. Quevedo, Lara Faccani, Anna L. Costa, Robert Landsiedel, Kai Werle, Wendel Wohlleben
Therefore, we decided to test the flash freezing method for characterization and modeling. Here we observe only small differences in z-averages as seen in Table S2, from 219.3 ± 2.3 nm to 281.0 ± 18.9 nm for CeO2 NM-212 fresh vs. freeze-thaw and 126.1 ± 1.0 nm to 176.4 ± 37.85 nm for BaSO4 NM-220. This results in an effective density of 2.200 ± 0.067 g/cm3 and 2.214 ± 0.029 g/cm3 for CeO2 NM-212 and 2.174 ± 0.000 g/cm3 and 2.034 ± 0.049 g/cm3 for BaSO4 NM220 for fresh and flash-frozen, respectively. These discrepancies have a negligible effect on transport properties, but they are a correction to the finding by Vila et al. (2017), which reported no differences between flash-frozen and fresh samples. While their investigation found differences in z-average, which agree with our findings, they did not report their particle size distributions. The flash freezing process seems to have promoted the aggregation of the ENMs, and as large ENM aggregates sediment at faster rates, this increases the effective delivered doses.
Mass spectrometry-based phospholipid imaging: methods and findings
Published in Expert Review of Proteomics, 2020
Al Mamun, Ariful Islam, Fumihiro Eto, Tomohito Sato, Tomoaki Kahyo, Mitsutoshi Setou
– The use of thin sections of human and animal (usually mice and rats) tissues is very common in PLs imaging. Human samples used for imaging include the biopsy and the archived postmortem tissues. Animals are usually euthanized by cervical dislocation or using anesthetics prior to tissue collection. In order to preserve the tissue anatomy and to halt the enzymatic degradation, tissues should be dissected rapidly followed by immediate flash-freezing using powdered-dry ice or liquid nitrogen (Figure 1). The frozen tissues are then stored at −80°C until sectioning.