China
Africa
Explore chapters and articles related to this topic
Fixation and Tissue Pretreatment
Published in Lars-Inge Larsson, Immunocytochemistry: Theory and Practice, 2020
Epon® and Araldite® are standard plastics for electron microscopy, and a vast amount of studies employing these has been carried out. As these plastics are not miscible with water, specimens have to be dehydrated and (usually) exposed to an intermedium (such as propylene oxide) before being embedded in the plastics. Dehydration is carried out in organic solvents (usually ethanols), but quick dehydration in DMP is possible (cf. Reference 102). DMP-dehydrated tissues need not be passed over propylene oxide. Cells grown on plastic surfaces (that can be dissolved by propylene oxide or xylene) should be efficiently dehydrated in absolute ethanol and then infiltrated with the embedding medium directly (cf. Appendix). In standard schemes polymerization is at 60°C. However, longer polymerization at 45°C may better preserve some antigens.72 Takamiya et al.120 found that the plastic monomer of embedding media may interact with and modify tissue amino groups. Controlled proteolytic treatment of the sections, however, was found to restore antigenicity.120 Although commonly employed for semithin plastic sections (vide infra) such proteolytic treatments seem to have been used only sparingly for ultrathin sections.
Emollient Esters and Oils
Published in Randy Schueller, Perry Romanowski, Conditioning Agents for Hair and Skin, 2020
John Carson, Kevin F. Gallagher
Under the heading of simple esters, we have another type of ester which was developed to meet several specific needs. One of the needs was economic. As mentioned above, fatty alcohols can be significantly more expensive than fatty acids. One way to reduce this cost is to react the fatty alcohol with a compound of lower cost which will maintain the alcohol functionality, yet dilute the cost. Two materials that react in this manner are ethylene oxide and propylene oxide.
Use of Biomarkers in Occupational Safety and Health
Published in Anthony P. DeCaprio, Toxicologic Biomarkers, 2006
Ehrenberg and his colleagues originally examined histidine adducts in hemoglobin of workers exposed to ethylene oxide or propylene oxide (32–35). However, since then hemoglobin adducts have been used to study worker populations with occupational exposure to a number of genotoxic chemicals, including aromatic amines (36), acrylamide (37), acrylonitrile (38) 1,3-butadiene (39), and benzene (40). The earliest methods utilized gas chromatograph–mass spectrometer (GC–MS) in order to obtain the sensitivity needed (41); however, tedious and complicated sample preparation methods hampered more widespread use in routine biomonitoring (31). A more recent modification of an Edman-degradation method by Tornqvist et al. (42) led to a more reliable determination of the N-terminal valine adducts to hemoglobin and improved greatly their suitability for use as a routine biomonitoring tool (43).
Targeting the PANoptosome with 3,4-Methylenedioxy-β-Nitrostyrene, Reduces PANoptosis and Protects the Kidney against Renal İschemia-Reperfusion Injury
Published in Journal of Investigative Surgery, 2022
Erdal Uysal, Mehmet Dokur, Faruk Kucukdurmaz, Serdar Altınay, Sait Polat, Kadir Batcıoglu, Efe Sezgın, Tuğçe Sapmaz Erçakallı, Aslı Yaylalı, Yakup Yılmaztekin, Zafer Cetın, İlker Saygılı, Osman Barut, Hatem Kazımoglu, Gokturk Maralcan, Suna Koc, Turkan Guney, Nadire Eser, Mehmet Sökücü, Sema Nur Dokur
The renal tissue samples were fixed in a five percent glutaraldehyde solution produced with Millonig’s phosphate buffer for three hours prior to electron microscopic examination. After shaking two times in the buffer for ten minutes, the samples were fixed in a 1 percent osmium tetraoxide solution prepared with Millonig’s phosphate buffer. After 2 hours of osmium tetraoxide fixing, the tissues were washed twice with phosphate buffer for ten minutes each time. After that, the tissues were sequentially dehydrated in 50 percent, 70 percent, 86 percent, 96 percent, and 100 percent of ethyl alcohol (each for 15 minutes). Following that, the tissues were treated with propylene oxide twice for fifteen minutes each time, followed by propylene oxide + resin for thirty minutes each time (twice). The renal tissue pieces were then placed in tubes containing newly prepared embedding material (resin) and swirled for 6 hours in a mixer. The kidney tissue sections were first placed in Beem® tablets the next day using newly manufactured embedding substance, and the material was then polymerized for two days in a 60 °C drying oven. The ultrathin slices (50 nm in thickness) were then cut using a Leica Reichert Ultracut S ultramicrotome (Austria). Saturated uranyl acetate produced in 70% ethyl alcohol and lead citrate solutions were used to stain the sections. Using a Transmission Electron Microscopy (TEM, Japan), the stained slices were examined and micrographed.
The oral health impact of electronic cigarette use: a systematic review
Published in Critical Reviews in Toxicology, 2020
Irene Yang, Shelly Sandeep, Jeannie Rodriguez
Chemicals and carcinogens in conventional cigarette smoke are known risk factors for various oral diseases including cancer and periodontal disease (Kumar et al. 2016; Vogtmann et al. 2017). E-cigarettes are marketed as a safer alternative to conventional smoking. However, components of e-cigarette vapor have known cytotoxic, genotoxic, and carcinogenic properties. E-cigarette vapor contains glycerol, propylene glycol, and nicotine, as well as fine particles of flavors, aroma transporters, trace amounts of carcinogens, and heavy metals (Grana et al. 2014), like nickel and aluminum (U.S. Department of Health and Human Services 2016). Humectants like glycerol and propylene glycol, when oxidized, lead to the formation of aldehydes like formaldehyde, acetaldehyde, and acrolein in e-cigarette vapor (Jensen et al. 2015). These free radical species are well-known as genotoxic agents (Yu et al. 2016) and have been shown to create inflammation leading to tissue damage (Lerner et al. 2015). Propylene glycol, when heated and aerosolized, is converted to propylene oxide, which is considered to be a carcinogen in humans (World Health Organization 2013). Other known carcinogens associated with conventional smoking have also been identified in the saliva of e-cigarette users. These include NNN and thiocyanate (Bustamante et al. 2018; Flieger et al., 2019).
miRNA-378a as a key regulator of cardiovascular health following engineered nanomaterial inhalation exposure
Published in Nanotoxicology, 2019
Quincy A. Hathaway, Andrya J. Durr, Danielle L. Shepherd, Mark V. Pinti, Ashley N. Brandebura, Cody E. Nichols, Amina Kunovac, William T. Goldsmith, Sherri A. Friend, Alaeddin B. Abukabda, Garrett K. Fink, Timothy R. Nurkiewicz, John M. Hollander
After excision of cardiac tissue, ∼1–2 mm3 pieces were cut and sent to the WVU Electron Microscopy Shared Facilities where they were processed and further imaged at the WVU Electron Microscopy Histopathology and Tissue Bank. Briefly, cardiac tissue was fixed in 2.5% glutaraldehyde in 0.1 M PBS (pH 7.4) for 60 min. After washing in PBS, samples were incubated in 1% osmium tetroxide containing 1% potassium ferricyanide for 60 min. Following additional PBS washes, tissue was dehydrated using a graded series of alcohol dilutions and propylene oxide. Samples were then incubated overnight in a 1:1 mix of propylene oxide and EPON. Samples were incubated in pure EPON for four washes, each for 60 min. Samples were cured in pure EPON inside the BEEM® Embedding Capsules Size 3 (Electron Microscopy Sciences, Hatfield, PA) starting at 37 °C for 24 h and then 60 °C for 48 h. Tissue was sectioned using an Ultramicrotome Leica EM UC7 (Leica Microsystems, Wetzler, Germany) and stained with uranyl acetate and lead citrate. Sections were imaged using the JEOL JEM-2100 TEM (JOEL, Akishima, Tokyo, Japan). Semi-quantitative analyses of mitochondrial size were processed through Fiji (NIH) and the Trainable Weka Segmentation (TWS) plugin by providing a probability map by which particle size could be determined. Selection of 5 mitochondria per group was used to perform analyses.