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Autoradiography
Published in Howard J. Glenn, Lelio G. Colombetti, Biologic Applications of Radiotracers, 2019
Sven Ullberg, Bengt Larsson, Hans Tjälve
The first experiments with liquid film emulsions were performed by Bélanger and Leblond.23 They applied a molten emulsion to the specimen by means of a paintbrush. Later, the method was changed in the way that the slide with the specimen was dipped in a molten emulsion.1, 24 This process is now widely used. The technique is performed as follows. In the darkroom, chrome alum-gelatin treated glass slides, with mounted, dewaxed, and hydrated tissue sections are dipped in the molten (+ 43° C) emulsion. The slides are dipped vertically in the emulsion and are then withdrawn slowly and steadily. The film should be gelled before allowed to dry, by cooling the slides for a few minutes on an ice-chilled metal plate immediately after they have been withdrawn from the emulsion. After drying overnight, exposure is performed in light-proof boxes at + 4° C. The NTB emulsions are developed in Kodak Dektol® developer, whereas Ilford Phen-X developer is used for the Ilford emulsions. After rinsing in distilled water, the films are fixed in 30% sodium thiosulfate. Staining may be carried out either before or after exposure. Stains applied after exposure may be heavily taken up by the gelatin of the emulsion, and there is also a possibility, especially with acid solutions, that grains may be removed. However, prestaining may also affect the emulsion and either cause the appearance of silver grains unrelated to radioactivity, or render the emulsions insensitive to the radioactivity.
Transmission of Persian medicine into China across the ages
Published in Vivienne Lo, Michael Stanley-Baker, Dolly Yang, Routledge Handbook of Chinese Medicine, 2022
Chen Ming 陳明, Michael Stanley-Baker
In the pursuit of longevity, medieval alchemists and experts in the Daoist arts looked to Western merchants dealing in drugs from Western regions. Persian drugs were frequently used by Chinese alchemists, as described in the work by the Late Tang and Five Dynasties Li Guangxuan 李光玄 from Bohai 渤海 (modern-day Binzhou in Shandong), the Jinye huandan baiwen jue 金液還丹百問訣 (Explanations of the ‘Hundred Questions’ on the Cyclically Transformed Elixir of Liquefied Gold, DZ 266). He writes: ‘That referred to as Numinous Elixir is not from here, it is said the ultimate drug is produced overseas, one should look to the interior of Persia, and from there seek white alum (baifan 白礬) and purple alum (zifan 紫礬). Or turn to the Uighur lands, and ask for diamonds and shards of jade’. Of the foreign drugs that could be used for refining elixirs referred to in alchemical texts in the Daoist Canon, many came from Persia, India, Khotan, Nanhai 南海 (modern-day Guangzhou), Silla, Beiting 北庭 (modern-day Ürümuqi). These were primarily mineral drugs, and plant drugs were in the minority. Frequently mentioned minerals from Persia include: Persian chalcopyrite (Bosi toushi 波斯鍮石), ‘true superior Persian brass with the hue of a horse tongue’ (zhen Bosi mashe se shang tou 真波斯馬舌色上鍮), Persian aurichalcite (Bosi zhetou 波斯折鍮), Persian lead (Bosi qian 波斯鉛), Persian Verdigris, white lead powder (hufen 胡粉), borax (da peng sha 大鵬砂), lithargyrum or lead oxide (mituoseng 密陀僧), sulphur ore (shiliu huang 石硫黃), naptha (shinao 石腦), iron sulphate (jiang fan 絳礬), ‘chicken dung’ alum (jishifan 雞屎礬),13 heaven’s brilliance sand (tianming sha 天明砂), yellow floriate ore (huang hua shi 黄花石), asbestos (buhui mu 不灰木), rock salt, sulphur imported by sea (boshang liuhuang 舶上硫磺), northern calamine (bei lüganshi 北盧甘石, Pers. tūtiya), pyrolusite (wumingyi, 無名異), Persian alum, Persian white alum, potassium chrome alum (zi fan 紫礬), Persian refined lead (Bosi qian jing 波斯鉛精), Persian red salts (Bosi chiyan, 波斯赤鹽), Persian silver ore (xigezhi, 悉悋脂), indigo (qingdai 青黛) and Carpesium abrotanoides (heshi 鶴虱).
Section Pretreatment, Epitope Demasking, and Methods for Dealing with Unwanted Staining
Published in Lars-Inge Larsson, Immunocytochemistry: Theory and Practice, 2020
The preparation of the tissue material and the sectioning procedures have already been dealt with in Chapter 2. Methods for attaching sections to slides are important since the sections often may detach during the lengthy staining procedures. The primary concern for all histological procedures is the use of clean glass slides. Although slides today are sold as “clean”, a glance at the material received often will throw doubts on the honesty of the manufacturer. Glass slides are, in our routine, cleaned first with xylene (in the fume cupboard) and second by rising with 70% ethanol. If glass slides are appropriately cleaned, sections will stick by capillary attraction without the use of any glue. Most technicians will object to such puritanism, however; therefore most laboratories (including, alas, my own) use different glues. Classical glues include (for paraffin sections) egg-white glycerin and glycerin-gelatin mixtures. Although these work well in histology routines, many experience problems with them in immunocytochemistry, particularly when protease digestion techniques are being applied. One way of making the sections stick is to expose the slides to the fumes of concentrated formalin (at room temperature or higher), but this may be undesirable for many antigens.36 Alternatives include polyvinyl acetate glue, and high-molecular-weight poly-l-lysine.25,31 In the investigation by Huang et al.,25 poly-l-lysine of the highest molecular weight (350,000 daltons) was best and was used in concentrations of 0.05 to 0.1% (in distilled water). For cryostat sections, slides were coated with the poly-l-lysine solution by the “blood smear” technique and were left to dry at room temperature for 5 to 10 min before being used to pick up frozen sections. Incidentally, the “blood smear” application technique requires use of clean slides. For paraffin sections, floating out on drops of poly-l-lysine solutions may be useful, and the same applies for plastic sections. The poly-L-lysine technique has been found to produce very firm attachment of the sections. However, with some protease digestion techniques, problems have been experienced also with poly-L-lysine-coated slides and for such applications, the old (and tedious) method of using meticulously clean slides with no adhesives is still preferred by us. However, the polyvinyl acetate glue method of Jarvinen and Rinne was found to withstand trypsin treatment.31 An alternative method to poly-l-lysine for cryostat sections is the use of chrome-alum gelatine. We find however, this method to be inferior to poly-l-lysine coating.
Could vitamin D protect against high fat diet induced damage in the arcuate nucleus in the rat: histological, immunohistochemical and ultrastructural study
Published in Ultrastructural Pathology, 2023
Hala Mohamed Hassanin, Omnia I. Ismail
For Light microscopic techniques, we identified the hypothalamic regions in the extracted brains by making two cuts; the first one was ventral to the optic chiasma and another one was behind the mammillary bodies. Rapidly, tiny parts of the hypothalamus were prepared and fixed in 10% formalin for 24–48 h according to the size of the specimens. Then, dehydration was done by putting the specimens in ascending grades of alcohol. After that, clearance in xylene was performed. Finally, the specimens were set in paraffin and serial coronal sections were done at 5 microns in thickness and stained with Gallocyanin-chrome alum stain for the purpose of displaying the general histological structure.16
Eugène-Louis Doyen and his Atlas d’Anatomie Topographique (1911): Sensationalism and gruesome theater
Published in Journal of the History of the Neurosciences, 2022
Doyen used a chemical process to fix whole cadavers, then used a motorized band saw with a sliding table to precisely cut sequential slices of even thickness in all three anatomic planes; he then used photography to record and label the various specimens, which were ultimately printed in his published atlas using the heliotype photomechanical process (Harrison 1871; Wall and Bolas 1897, 133–36, 337). The heliotype process allowed photographs to be rapidly and inexpensively copied using a printing press. Heliotypes were made by exposing a photographic negative onto a gelatin film, sensitized with chromate of potash (potassium bichromate), and hardened with chrome alum [chromium(III) potassium sulfate].
The Shh/Gli1 signaling pathway regulates regeneration via transcription factor Olig1 expression after focal cerebral ischemia in rats
Published in Neurological Research, 2022
Hong Zhao, Xiao-Yu Gao, Xiao-Jun Wu, Yong-Bo Zhang, Xun-Fen Wang
After MCAO or injection of cyclopamine (1d, 3d, or 7 d), the rats were anesthetized with 10% chloral hydrate (300 mg/kg). The aorta was perfused with 200 mL of normal saline, followed by 300 mL of 4% paraformaldehyde (PFA) in 0.1 M phosphate buffered saline (PBS, pH 7.4). The brains were harvested from the rats, fixed in PFA for 24–48 h, and then cryoprotected in an ascending gradient of sucrose solutions. The brains were then frozen in solid carbon dioxide and consecutive 20 μm-thick coronal sections were prepared using a cryostat (Cryocut1800; Leica Instruments). The sections were mounted on gelatin/chrome alum-coated glass slides then stored at −30°C.