Cation toxicity

Cation toxicity Penicillins are generally administered as the sodium or potassium salt. Toxicities may be caused by the large quantities of sodium or potassium that accompany the penicillin. Sodium excess may result in hypokalemia. This can be avoided by using the most potent antibiotic, which permits lower doses of drug and accompanying cations. 

The most significant finding of this phase of the study was that very low concentrations of the cations studied could produce both synergistic and antagonistic effects. Thus it is clear why previously reported results on cation toxicity in this field have differed qualitatively from those obtained by biologists. Undoubtedly, since strict control over the ionic constituents of media was not exercised, synergistic and antagonistic effects were overlooked. 

Toxicity of fight metal cations is significantly affected by the presence or absence of extremely low concentrations of antagonists and synergists. When dealing with cation toxicity situations, it is essential that a complete ionic analysis of the environment be made so that valid decisions on ionic alterations can be made. 

Cation toxicity Toxic effects from Na+ or K+ may occur when high doses of penicillin salts are used in patients with cardiovascular or renal disease. 

Shaw, W.H.R. 1961. Cation toxicity and the stahihty of transition-metal complexes. Nature 192 754-755. 

This chapter discusses quantitative structure-activity relationships (QSARs) for predicting cation toxicity, bioconcentration, biosorption, and binding strength. Several approaches were used to identify these QSARs. First, the test systems, test substances, QSARs, and statistical analyses of each QSAR were extracted from the references cited by Walker et al. (2003). These efforts produced 21 references associated with 97 QSARs for predicting cation toxicities (Table 5.1). These QSARs are discussed in more detail in chapter Sections 5.2,5.3, and 5.5. 

QSARs for Predicting Cation Toxicity, Bioconcentration, Biosorption... 

MOST COMMON PHYSICOCHEMICAL PROPERTIES USED TO PREDICT CATION TOXICITY... 

Walker et al. (2003) died more than 100 studies that described the relationships among 24 properties of cations and their toxic actions. However, Walker et al. (2003) did not provide any of the QSARs used to describe those relationships. The purpose of this chapter section is to discuss the most commonly used physicochemical properties in QSARs used to predict cation toxicity. 

The standard electrode potential is a characteristic of bulk metal reflecting the capacity of a metal to generate positive ions in aqueous solution. Eight studies used standard electrode potential (E°) to predict cation toxicity (Table 5.5). All these studies were... 

Vj is the intrinsic (van der Waals) molecular volume, n is the solute ability to stabilize a neighboring charge or dipole by nonspecific dielectric interactions, and and a , are the solute ability to accept or donate a hydrogen in a hydrogen bond. The coefficients m, s, b, and a are constants for a particular set of conditions, determined by multiple linear regression of the LSER variable values for a series of chemicals with the measured value for a particular chemical property. This equation was used to estimate cation solubility and predict cation toxicity to Vihrio fischeri, Daphnia magm, and Leuciscus idus melanotus. 

Studies Using Standard Electrode Potential to Predict Cation Toxicity... 

Studies Using the Negative Logarithm of Solubility Product Equilibrium Constant (pK p) to Predict Cation Toxicity... 

The standard reduction-oxidation potential represents the absolute difference in electrochemical potential between an ion and its first stable reduced state (AEq), or in other terms, the ability of an ion to change its electronic state. Nine studies used standard reduction-oxidation potential to predict cation toxicity (Table 5.7). These studies were reviewed by Walker et al. (2003), except for Workentine et al. (2008) and Mendes et al. (2010). None of the QSARs were described or discussed by Walker et al. (2003). 

Kaiser s (1980,1985) QSARs for Predicting Cation Toxicity Using Atomic Number, Ionization Potential Differential, and Standard Reduction-Oxidation Potential... 

Tatara et al. (1997,1998) QSARs for predicting cation toxicity using standard reduction-oxidation potential alone or in combinations with standard reduction-oxidation potential, atomic number, ionization potential differential, covalent index, logarithm of the first hydrolysis constant, or Pearson and Mawby softness parameter alone or in combination with logarithm of the first hydrolysis constant... 

Enache et al. (2000) QCARs and Enache et al. (2003) QCAR for predicting cation toxicity using atomic number, atomic weight, ionization potential differential and standard reduction-oxidation potential... 

Mendes et al. (2010) QCARs for Predicting Cation Toxicity Using Standard Reduction-Oxidation Potential, Electronegativity, Pearson and Mawby (1967) softness parameter and in combination with the Logarithm of the First Hydrolysis Constant, Covalent Index, and Atomic Radius... 

Source Data from L.F. Mendes, E.L. Bastos, and C.V. Stevani. Prediction of Metal Cation Toxicity ... 

Of the 27 QSARs that used AEq to predict cation toxicities, 13 used combinations of AEq, an, and AIP (labeled as 1 in Table 5.13), 5 only used AEg (labeled as 2 in Table 5.13), and 2 used combinations of AEq, AW, and AIP (labeled as 3 in Table 5.13). Of the 13 QSARs that used combinations of AEg, AN, and AIP, Kaiser s (1980) QSAR for 12 cations had the highest r adding In , Rh , and Pd to those 12 cations decreased r (Table 5.13). Of the 5 QSARs that only used AEg, the Mendes et al. (2010) QSAR not only had the highest coefficient of determination, but the second-highest number of cations (18), only missing Cr and La from the McCloskey et al. (1996) QSAR for 20 cations (Table 5.13). Of the 2 that used combinations of AEg, AW, and AIP, reducing the number of cations from 12 to 11 by eliminating Cu + produced a more robust QSAR as explained previously (Table 5.13). 

Turner et al. (1985) and Khangarot and Ray (1989) did not report QSARs for electronegativity. However, Khangarot and Ray did use linear regression analysis to describe the relationship between 23 cation toxicities and standard 2-day Daphnia magna ECsg values based on immobilization r =0.542 and p< 0.001. The Turner et al. (1985) and Khangarot and Ray (1989) test systems and cations are listed in Table 5.14. 

QCARs for Predicting Cation Toxicity and Bioconcentration Factors for the Mussels, Mytilis edulis and Perna viridis Using the Covalent Radius, Logarithm of the First Hydrolysis Constant, Pearson and Mawby Softness Parameter, and the Ionic Index... 

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