Fixation methods

Somljo It all depends on the fixation method. We use osmium ferricyanide to selectively infiltrate the SR. If we use intermediate high-voltage electron microscopy, we can look at thicker specimens, and this technique provides more extensive views than obtained from the usual thin sections. This is the same information we get when we infiltrate the SR with Fluo-3. These pictures are pretty reliable. Furthermore, if you want to confirm without chemical fixation, methods such as rapid freezing are available. All these techniques give the same pictures, which vary according to the smooth muscle type. 

The stain/fixation method is usually used for surface markers that can withstand fixation and is followed by the application of a DNA-binding fluoro-chrome. The fixation/stain method is used not only for surface markers that can withstand fixation, but also for intracellular constituents, such as cytoplasmic proteins, nuclear membrane, and nuclear proteins. This is accomplished by using a crosslinking fixative (e.g., paraformaldehyde [PFA] or formalin) followed by a permeabilizing agent (e.g., Triton X-100, Tween-20, saponin, or lysolecithin). Some of the precipitating agents (e.g., ethanol, methanol, or acetone) can also be used for permeabilization after the initial fixation with PFA or formalin, or they can be used alone for both fixation and permeabilization (see Chapter 8). 

MARCOR Environmental, Inc. s, Advanced Chemical Treatment (ACT) is a chemical fixation method for the treatment of contaminated soils, sediments, and sludges. The vendor claims that by mixing contaminated materials with ACT reagents, the contaminants are oxidized, catalyzed, and mineralized. Target contaminants may include coal tar wastes polycyclic aromatic hydrocarbons (PAHs) benzene, toluene, ethylbenzene, and xylenes (BTEX) chromium copper and lead. 

Palade, Porter, and Sjostrand perfected thin sectioning and fixation methods for electron microscopy of intracellular structures. 

Y3. Yu, Y., Leng, C. G., Kato, Y., and Ohno, S., Ultrastructural study of glomerular capillary loops at different perfusion pressures as revealed by quick-freezing, freeze-substitution and conventional fixation methods. Nephron 76, 452-459 (1997). 

In acute and first chronic implantations in rabbits, the stimulator structures showed an excellent performance. Only minor foreign body reaction occurred. The fixation support structures are located apart from the stimulation site. By this, more choices are available to fix the structure to the retina. Possible ophthalmologic fixation methods include laser scar formation and retinal tacks without affecting the ganglionic structures directly under the stimulation elec-... 

Finally, many of the newer fixation methods incorporate microwave treatments, either for the fixation itself or to speed fixation of other reagents (6). Direct microwave fixation is probably fixation due to heat, and is primarily a coagulation of the proteins. In conjunction with fixatives, microwaving probably speeds the reaction by heating the solution. It also perhaps speeds the penetration of the solution due to the relaxing of the cell structure. 

Blood cells of C. intestinalis showed low and variable levels of vanadium in morula cells (154). In this species the primary vanadium storage site was determined to be the granular amoebocyte. It was first concluded that significant vanadium is present in the morula cells of the species A. mentula and Ascidiella aspersa, but the various cell types were not distinguishable (155), When the same two species were reexamined with improved fixation methods it was concluded that sig-... 

Various kinds of biological CO fixation methods such as afforestation, marine fertilization and microalgac production have been proposed. 

Lowering of enzyme loading is recommended for enzymes with high specific activity which is easily achieved by common fixation methods. Enzyme activity in crystals was diluted by co-crystallization with inactivated enzyme... 

On the other hand, in the case of enzymes with low specific activity, tight packing in crystals may be a useful fixation method when excessive inert carrier material would otherwise preclude reasonable reaction conditions. 

Kimoto Y, Tohyama M, Satoh K, Sakumoto T, Takahashi Y, Shimizu (1981) Fine structure of rat cerebellar noradrenaline terminals as visualized by potassium permanganate in situ perfusion fixation method. Neuroscience, 6, 47-58. 

Lowering of enzyme loading is recommended for enzymes with high specific activity which is easily achieved by common fixation methods. Enzyme activity in crystals was diluted by co-crystallization with inactivated enzyme [6]. On the other hand, in the case of enzymes with low specific activity, tight packing in crystals may be a useful fixation method when excessive inert carrier material would otherwise preclude reasonable reaction conditions. 

Drosophila embryos are protected both by an outer layer called chorion and an impermeable and opaque vitelline membrane. Therefore preparation of whole mount Drosophila embryos for staining with antibodies and/or other fluorescent markers must go through the following steps chorion removal, fixation, vitelline membrane removal, and membrane permeabilization. The next subsection introduces the basic procedures for embryo collection and chorion removal that are common to all protocols described here, as well as the two most common fixation methods with or without methanol (the latter requiring hand devitellinization of embryos). The first one works well for immunostaining, while the second is ideal for F-actin staining with phalloidin. 

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