Autoradiography
Howard J. Glenn, Lelio G. Colombetti in Biologic Applications of Radiotracers, 2019
Several different types of cryostat equipment have been constructed, and a few of them have been marketed. Two advanced models which were relatively recently developed will be described shortly. They differ mainly in size. The large one (LKB® 2250) allows the sectioning of such large specimens as a 5 kg pregnant monkey 45 cm × 15 cm (Figure 4). The other one can be used for mice and rats 16 cm × 15 cm (LKB® 2258). Both can also be used for small specimens such as rat fetuses. The good stability also allows the sectioning of such hard tissues as teeth. The sectioning is done on a specially designed heavy-duty microtome, which is built into the cryostat. The motor driving the microtome sledge is maneuvered automatically or by a knee control unit with adjustable speed. The knife-holder arrangement is very stable; the pillars holding the knife move vertically. The thickness of the section is determined by the downward feed of the knife, the specimen holder being moved only horizontally. The section thickness can be varied in a continuous range from 1 to 999 μm.
Safety Considerations on Siting and Shielding
Bertil R. R. Persson, Freddy Ståhlberg in Health and Safety of Clinical NMR Examinations, 2019
The cryostat is both a “pressure vessel” and a “vacuum vessel” and must therefore be certified as such before installation. Normally the cryostat is under vacuum except for the helium and nitrogen cans. To prevent explosion of a cryogenic magnet if its internal pressure increases due to iced-up ventilation ducts or spontaneous quench, the internal cans of the vacuum vessel, as well as the helium and nitrogen cans, must be protected against overpressure. This is normally done by “bursting discs” which release any excess pressure to the atmosphere. Since this could involve large quantities of gas, the magnet room should be well ventilated of remaining exhaust gas to the outside atmosphere. Therefore, a special quench vent is attached to the blow-out diaphragm of the helium reservoir.
Proton Accelerators
Harald Paganetti in Proton Therapy Physics, 2018
The magnetic field strength in the commercially available cyclotrons is between 2 and 3.5 T. Both conventional copper magnet coils [18,19] and, since a few years, superconducting coils are used for therapy cyclotrons. Advantages of superconducting coils are low power consumption (20 kW, mostly for the liquid helium cooling, versus 300–350 kW) and, especially, stronger magnetic field. This allows the cyclotron to be smaller and less heavy, but more importantly, since the iron is magnetically more saturated at strong fields. This makes the magnetic field less sensitive to small imperfections in the iron. Also, when switching on, cycling (a ramping procedure to erase the “magnetic history,” in which the magnet is first set at a stronger field than needed) is not needed. In the superconducting (SC) cyclotron at PSI (Varian) [20], the coil is mounted in a closed ring and cooled by means of liquid helium. As is also visible in Figure 3.3, the coil ring is suspended in a vacuum cryostat providing the thermal insulation. In addition, the coil is surrounded by a heat shield (at 40–70 K) and many layers of super insulation. The outside of the cryostat is at room temperature. Therefore, opening of the cyclotron does not require warming up of the coil. Due to the insulation between coil and magnet iron, temperature effects in the iron, which occur in cyclotrons with normal conducting coils, are not present. Disadvantages of the SC coil are the risk of a quench due to operational errors (which are normally prevented by the control system) or when a high-intensity beam is lost or stopped close to the coil.
Clinicopathological characteristics and predictors of poor outcome in anti-glomerular basement membrane disease – a fifteen year single center experience
Published in Renal Failure, 2021
Zafirah Zahir, Asif Sadiq Wani, Narayan Prasad, Manoj Jain
Renal biopsy evaluation: Two core biopsies, taken under ultrasound guidance by biopsy gun, one for light microscopy and immunofluorescence each, were evaluated by either of the two nephropathologists. For light microscopy, standard sections were cut from renal biopsy received in 10% buffered formalin. Biopsies were evaluated for endocapillary, extracapillary or mesangial proliferation, fibrinoid necrosis, interstitial inflammation, percentage of glomerulosclerosis, interstitial fibrosis, and tubular atrophy. For imunofluorescence, the biopsy was transported in normal saline. Standard sections were cut in cryostat at a temperature of −20 °C. The percentage of sclerosed glomeruli were graded as Grade 1(<25%), Grade 2 (25–50%), and Grade 3 (>50%). Interstitial fibrosis and tubular atrophy were graded as mild (<25%), moderate (25–50%), and severe (>50%). Interstitial inflammation was also graded as mild (<25%), moderate (25–50%), and severe (>50%).
Angelica gigas root ameliorates ischaemic stroke-induced brain injury in mice by activating the PI3K/AKT/mTOR and MAPK pathways
Published in Pharmaceutical Biology, 2021
Se-Eun Lee, Chiyeon Lim, Suin Cho
Phosphate-buffered saline (PBS) was purchased from Bio Basic Inc. (Markham, Ontario, Canada). 2,3,5-Triphenyl-tetrazolium chloride (TTC), cresyl violet, Evans blue (EB), and propidium iodide (PI) were obtained from Sigma-Aldrich Co. (St. Louis, MO, USA). The optimal cutting temperature compound cryostat embedding medium was obtained from Thermo Fisher Scientific (Waltham, MA, USA). Primary antibodies against B-cell lymphoma 2 (Bcl-2), bcl-2-like protein 4 (Bax), phospho-phosphoinositide 3-kinase (p-PI3K), protein kinase B (PKB, AKT), phospho-extracellular signal-regulated kinase (p-ERK), ERK, phospho-c-Jun N-terminal kinase (p-JNK), JNK, phospho-p38 mitogen-activated protein kinase (p-p38), p38, and manganese superoxide dismutase (MnSOD) were purchased from Cell Signalling Technology (Danvers, MA, USA). PI3K, p-AKT, phospho-mammalian target of rapamycin (p-mTOR), sirtuin 1 (SIRT1), and β-actin were obtained from Santa Cruz Biotechnology Inc. (Dallas, TX, USA). Aquaporin 4 (AQP4) was purchased from Abcam Inc. (Milton, Cambridge, UK). The bovine serum albumin (BSA) standard and enhanced chemiluminescence (ECL) western blotting chemiluminescent substrate were purchased from Thermo Fisher Scientific.
Enhanced gut barrier integrity sensitizes colon cancer to immune therapy
Published in OncoImmunology, 2018
Neal Bhutiani, Qingsheng Li, Charles D. Anderson, Heather C. Gallagher, Magdia De Jesus, Rajbir Singh, Venkatkrishna R. Jala, Mostafa Fraig, Tao Gu, Nejat K. Egilmez
Colon and tumor tissues were harvested from mice, embedded in Tissue-Plus Optimal Cutting Temperature (OCT) Compound (Fisher HealthCare, Houston, TX, USA) and snap-frozen in liquid nitrogen. Serial cryosections (25 μm) were prepared with a Cryostar NX70, Thermo Scientific cryostat at −19°C (Kalamazoo, MI, USA). Cryosections were kept at room temperature for at least 24 h prior to staining. A previously described immunostaining protocol was used with modifications.38 For analysis of IL-10RA expression, staining antibodies were added sequentially in the following order: IL-10RA- phycoerythrin (PE) (Novus Biologicals, Littleton, CO), CD324 (E-Cadherin) Alexa Fluor-488 (Thermo Fisher, Waltham, MA). Sections were washed twice with 1X PBS-T and processed for imaging. For analysis of colon sections, staining antibodies were added sequentially in the following order: IL-10RA- phycoerythrin (PE) (Novus Biologicals, Littleton, CO), CD324 (E-Cadherin) Alexa Fluor-488 (Thermo Fisher, Waltham, MA). Antibodies were diluted with 2% fetal calf serum (FCS) in 1X PBS pH 7.4 to 1:25 for IL-10RA-PE, and 1:25 for CD324 E-Cadherin Alexa Fluor-488. Each antibody was sequentially incubated at 37°C for 40 mins. Sections were washed twice with 1X PBS-T and Prolong Gold anti-fade reagent (Thermo Fisher, Waltham, MA) was added to the slides prior to imaging. Images were captured using a Leica SP5 confocal laser scanning microscope (Leica, Wetzlar, Germany) and processed using Fiji Software.39 Panels containing confocal images were generated using Adobe Photoshop version 13.0 x32. Images were marked using the drawing tools to highlight the results and to provide orientation of the tissues.
Related Knowledge Centers
- Cryogenics
- Helium
- Liquid Helium
- Vacuum Flask
- 1-K Pot
- Dilution Refrigerator
- Magnetic Refrigeration
- Magnetic Resonance Imaging
- Liquid Nitrogen
- Frozen Section Procedure