Lead citrate

Fig.1. Electron micrograph of a mast cell in human heart tissue. The cytoplasm contains numerous secretory granules. The mast cell is adjacent to a coronary blood vessel, surrounded by collagen fibers and close to a myocyte. Uranyl acetate and lead citrate stained. Orig. magnif. lO.OOOx. 

Reynolds E. S. (1963). The use of lead citrate at high pH as an electron opaque stain in electron microscopy. Journal of Cell Biology 17 208-212. 

III. Transmission electron microscopy of radish seeds Transmission electron microscopy (TEM) of radish seeds was done as listed below For TEM preparations, the specimens after fixation and dehydration, were embedded in Epon 812 resin (Luft, 1961). Thick sections (ca. 1mm each) were stained with 0.1% toluidine blue and observed with a Zeiss light photomicroscope. Thin sections, obtained with a diamond knife on a Supernova microtome, were sequentially stained at room temperature with 2% uranyle acetate (aqueous) for 5 min and by lead citrate for 10 min (Reynolds, 1963). Ultrastructural studies were made using a Philips CM12 transmission electrone microscope (TEM) operated at 80 KV. 

Collect sections on acetone-washed copper grids (see Subheading 2.2.) View directly or positive stain with uranyl acetate and lead citrate (sections can be stored in a grid box)... 

Lead citrate/uranyl acetate6 Step 1 Float or immerse sections for 10-30 min on filtered 1-2% aqueous uranyl acetate (or in EtOH) wash with ultrapure H20 (three beakers of 50 mL each) by dipping grids held with a forceps dry for 5 min Step 2 Place drops of lead citrate (lead carbonate free) onto a wax surface (parafilm or dental wax) in a Petri dish line edges of dish with pellets of KOH float grid with sections (sections face down) for 4-5 min (if overstained 2-3 min and dilute stain) wash grids with sections in ultrapure H20 Nonselective enhancement of membrane contrast, ribosomes, and nuclear material proteins and lipid droplets... 

Summarized from Roland and Vian (19). The reader is referred to Chapter 16 and ref. (40) for discussions of ultrastractural cytochemistry. b There is a number of lead citrate formulations. A modification of the Reynold s procedure (60a) is that of Sato (61). Meticulous care must be taken to keep the lead citrate solution free of lead carbonate, which originates via reaction of lead citrate with atmospheric C02. Once prepared, the solution can be stored in capped syringes at 4°C. 

Stain with uranyl acetate and lead citrate. 

Place drops of Sato s (61) lead citrate onto parafilm in a Petri dish lined with NaOH pellets use a 1-cc syringe equipped with a 0.2-pm filter. 

Embed the dehydrated samples in epoxy resin (Quetol 653), cut into thin sections, stain with 4% uranyl acetate and 0.4% lead citrate, and examine with a Jeol 1200EXS electron microscope. 

Lead citrate, molecular formula, 6 638t Lead compounds, 14 729, 782-804. See also Lead entries... 

Stain embedded sections lightly in uranyl acetate and lead citrate (optional). Frozen sections may be stained with osmium tetroxide vapor. Staining with OSO4 or uranyl acetate may be conducted without obscuring the gold particles. Wash and examine under the electron microscope. 

Lesion in bovine dentin with tubules protruding from degraded intertubular matrix (left degraded matrix right intact matrix). Demineralization in 0.1 M acetic acid pH 4.0, with subsequent exposure to bacterial collagenase. Fixed and demineralized with glutar-dialdehyde-acetic acid, post-fixed with osmium tetroxide ultrathin sections stained with uranyl acetate - lead citrate. 

Reynolds lead citrate (6) 1.33 g lead nitrate, 1.76 g trisodium citrate 2H2O 30 mL deionized glass-distilled water, and 8.0 mL 1 ANaOH (see Note 3). 

Stain the grids with uranyl acetate for 5-10 min, rinse in water, and stain with lead citrate for 1-2 min. They are now ready for final examination in the electron microscope see Note 12). 

A typical super-rate burning of an HMX-GAP composite propellant is shown in Fig. 7.43. The lead catalyst is a mixture of lead citrate (LC PbCi), Pb3(C5H50y)2-x H20, and carbon black (CB). The composition of the catalyzed HMX-GAP propellant in terms of mass fractions is as follows gap(0.194), hmx(0-780), lg(0 020), and, q 0.00G). GAP is cured with 12.0% hexamethylene diisocyanate (HMDI) and then crossUnked with 3.2 % trimethylolpropane (TMP) to... 

Fig. 7.44 Effect of catalyst on the burning rate of GAP copolymer, showing no burning rate increase by the addition of lead citrate and/or carbon black.

During primary wall formation the plastids contain starch and other materials which stain heavily with uranyl acetate and lead citrate. When the tracheid starts to form the Si layer, the plastid becomes surrounded by an endoplasmic reticulum. While the fate of these compounds is unknown, it can be envisaged that they are used for generation of energy and/or a source of cell wall materials. 

Post-staining Procedure. Immunogold labelled sections were post-stained in saturated aqueous uranyl acetate for 15 min and lead citrate for 10 min... 

Figure 1-7 Electron micrograph of a thin section of a young epidermal cell of a sunflower. The tissue was fixed and stained with uranyl acetate and lead citrate. Clearly visible are the nucleus (N), mitochondria (M), chloroplasts (C), a Golgi body dictyosome (G), endoplasmic reticulum, vacuole (V), cell wall, plasmodesmata, and cuticle (upper right, thin dark layer). Micrograph courtesy of H. T. Horner.

Stain resin sections with 1% methanolic uranyl acetate and lead citrate according to routine electron microscopy procedures. If ultrathin frozen sections are being... 

After glutaraldehyde fixation (Section 3.1 1 2., step 8), fix the cells further with 1% osmium tetroxide, saturated uranyl acetate, dehydrate in an ascending series of ethanol (70, 90, 100%), and embed in epoxy resin. Ultrathin sections of the block, stained with 1% methanolic uranyl acetate and lead citrate, will reveal immunolabeling on the outer surface of the cells... 

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