Activator sodium

The detection and quantitation of y-emission from is accompHshed by well counting. A thaUium-activated sodium iodide crystal, having a well... 

L. Pasteur (aged 26) began work on optically active sodium ammonium tartrate. 

Pitman, M.G. Saddler, H.D. W. (1967). Active sodium and potassium transport in cells of barley roots. Proceedings of the National Academy of Sciences, USA, 57, 44-9. 

The saxitoxins function by binding to a site on the extracellular surface of the voltage-activated sodium channel, interrupting the passive inward flux of sodium ions that would normally occur through the channel while it is in a conducting... 

OA Candia, PJ Bently, PI Cook. (1974). Stimulation by amphotericin B of active sodium transport across amphibian cornea. Am J Physiol 222 1438. 

XP Shi, OA Candia. (1995). Active sodium and chloride transport across the isolated rabbit conjunctiva. Curr Eye Res 14 927-935. 

Scintillation counters are constructed by coupling a suitable scintillation phosphor to a light-sensitive photomultiplier tube. Figure 25 illustrates an example of a scintillation counter using a thallium-activated sodium iodide crystal. 

SADP or sulfo-SADP also have been used to study the phenylalanine-methionine-arginine-phenylalanine-amide-activated sodium channel (Coscoy et al., 1998), various apolipoprotein E isoforms (Mann et al., 1995), the high-affinity phenylalkylamine Ca2+ antagonist binding protein from guinea pig (Moebius et al., 1994), the interaction of non-histone proteins with nucleosome core particles (Reeves and Nissen, 1993), and the interactions among cytochromes P-450 in the endoplasmic reticulum (Alston et al., 1991). See Chapter 28 for methods of using photoreactive heterobifunctional crosslinkers to study protein interactions. 

Coscoy, S., Lingueglia, E., Lazdunski, M., and Barbry, P. (1998) The Phe-Met-Arg-Phe-amide-activated sodium channel is a tetramer./. Biol. Chem. 273, 8317. 

Neurotoxin that preferentially binds to activated sodium channels and increases the intracellular calcium concentration. It prolongs the action potential duration in the heart. It is obtained from sabadilla seeds (Schoenocaulon officinale). Yellowish-white amorphous powder that retains water and melts at 356°F. It is insoluble in water but slightly soluble in ether. Various salts (solids) have been reported. The nitrate is sparingly soluble in water. 

The epilepsies constitute a common, serious neurological disorder in humans, affecting approximately 60 million people worldwide. Well in excess of 40 distinct epileptic syndromes have been identified to date. Current treatment is only symptomatic except in uncommon instances when surgical treatment is possible. While available antiseizure medications target ion channels such as the y-amino-butyric acid (GABA)a receptor and voltage activated sodium (Na+) channels, current research seeks to elucidate the cellular and molecular mechanisms by which a normal brain becomes epileptic. Hopefully, this research will lead to the identification of new targets for which small molecules can be identified and used for prevention or cure of epilepsy. 

Virkki, L. and M. Nikinmaa. 1993. Tributyltin inhibition of adrenergically activated sodium/proton exchange in erythrocytes os rainbow trout (Oncorhynchus mykiss). Aquat. Toxicol. 25 139-146. 

ATP is used not only to power muscle contraction, but also to re-establish the resting state of the cell. At the end of the contraction cycle, calcium must be transported back into the sarcoplasmic reticulum, a process which is ATP driven by an active pump mechanism. Additionally, an active sodium-potassium ATPase pump is required to reset the membrane potential by extruding sodium from the sarcoplasm after each wave of depolarization. When cytoplasmic Ca2- falls, tropomyosin takes up its original position on the actin and prevents myosin binding and the muscle relaxes. Once back in the sarcoplasmic reticulum, calcium binds with a protein called calsequestrin, where it remains until the muscle is again stimulated by a neural impulse leading to calcium release into the cytosol and the cycle repeats. 

Cheek JM, Kim KJ, Crandall ED (1989) Tight monolayers of rat alveolar epithelial cells bioelectric properties and active sodium transport. Am J Physiol 256 (3 Pt 1 ) C688-C693... 

O. A. Candia and P. S. Reinach. Thermodynamic analysis of active sodium and potassium transport in the frog corneal epithelium. Am J Physiol 242 F690-F698 (1982)... 

The dispersity or homogeneity of the reductant in a reaction system sometimes plays a decisive role. It is also important for synthetic practice. Crandall and Mualla (1986) compared reduction of 7-methylocta-5,6-diene-2-one [H3C-C(CH3)=C=CH-CH2-CH2-C(0)-CH3] in THF by the action of naphthalene-sodium, on the one hand and, by sonically activated sodium on the other. In both the cases, one-electron transfer yields the anion-radical salt of the allenic ketone with sodium. However, only in the case of sonicated sodium is this salt stabilized, eventually giving H3C-C(CH3)=C=CH-CH2-CH2-C(0H)-CH3 along with cyclic products (l-methyl-2-isopropylidene cyclopentanol and l-methyl-2-isopropylcyclopent-2-enol). If naphthalene-sodium is used, only the cyclic alcohols are obtained as mentioned earlier. 

Figure 2.2 Diagram of a voltage-activated sodium channel protein. The channel is composed of a long chain of amino acids intercormected by peptide bonds. The amino acids perform specific functions within the ion channel. The cylinders represent amino acid assemblies located within the membrane of the nerve cell and responsible for the foundation of the ion pore.

Lime Reactor The efflnent from the EDV system is pumped to an agitated reactor vessel where the EDV efflnent is reacted with lime to form calcium sulfite and active sodium species via the following reactions ... 

Gamma-ray counters are usually made from a cylinder of activated sodium iodide, which is enclosed in an aluminum shell, with one side of the cylinder lying in close proximity to a photomultiplier tube. The flow cell is composed of a U tube or coil (Figure 7.12) placed into the core of the cylinder. Radioactivity present in the column effluent is blocked from escaping by the dense sodium iodide, and the energy is converted into light, which is measured by the photomultiplier tube. 

Sodium retention and hypo albumin aemi a are constant features. The former appears consequent on disturbed blood volume distribution, withslanch-nic dilatation and reduced effective central arterial blood volume leads to sodium retention. Hypoalbu-minaemia associated with reduced hepatic albumin synthesis, and raised portal pressure associated with obstruction to flow, as well as active sodium retention all predispose to ascites. Hypoalbuminaemia is associated with reduced hepatic synthesis. 

Phenolphthalein is partially absorbed (about 15% of a given dose) and excreted into the bile hence, if it is taken constantly, it will accumulate and exert too drastic an action. It inhibits active sodium and glucose... 

An improved method of preparing alkyl azides has been reported wherein Carbitols are used as solvents for the interaction of an alkyl halide and commercial sodium azide [10]. The use of activated sodium azide [34] is not necessary. Sealed-tube reactions for alkyl azides are hazardous a violent explosion has been reported in an attempt to seal such a tube [35]. No reactions reported in this chapter involve sealed tubes. Table II describes the conditions and azides prepared using the Carbitol solvents. 

So-called bradycardic drugs, relatively selective If sodium channel blockers (eg, ivabradine), reduce cardiac rate by inhibiting the hyperpolarization-activated sodium channel in the sinoatrial node. No other significant hemodynamic effects have been reported. Ivabradine appears to reduce anginal attacks with an efficacy similar to that of calcium channel blockers and 3 blockers. The lack of effect on gastrointestinal and bronchial smooth muscle is an advantage of ivabradine, and FDA approval is expected. 

Cellular Equilibration Processes Depending on Active Sodium Potassium... 

Before injection, monitoring probes re placed on the outlet lines close a the exit from the tank being tested. These probes consist of a l-in.-diarr.-tter, thalium-activated sodium-iodide scintillation crystal, a small portable meter, and a recorder. 

Such mechanisms might be questioned since in a recent work Goodman and Arnon (55) demonstrated the absence of initiator s fragments in the resulting polymer. In the course of their studies, polymerisation of y-benzyl-i.-glutamate was initiated in dioxane by 9-fluorenyl potassium or by radio-active sodium methoxide. The polymer produced by the former initiator was precipitated and examined spectrophotometrically. For Mjl ratio of 60 its degree of polymerisation was found from its intrinsic viscosity, to be about 180 and its solution did not absorb at A = 300 mfi where a strong absorption band (e = 104) of the fluorenyl moiety should appear. On the other hand, all the fluorenyl residues were found in the solution left after precipitation of the polymer. 

Similar results were obtained with radio-active sodium methoxide. The activity of the precipitated polymer was only 0.7% of that expected had each polymer molecule contained one methoxy group. Again, virtually all the activity was found in the residual solution. 

To present a quantitative example of the energy conversions involved in scintillation detection, we trace the results of the interaction of a single 1.17-MeV 7 ray from 60Co with a thallium-activated sodium iodide crystal [Nal(TI)] ... 

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