Nonionic Agents Research Articles

Ion flotation of cadmium(II) and zinc(II) in the presence of proton-ionizable lariat ethers.

Competitive flotation of Cd(II) and Zn(II) from very dilute aqueous solutions by proton-ionizable lariat ethers in the presence of nonylphenol nona(ethylene glycol) ether as a nonionic foaming agent is reported. Influences of structural variation within the collector (identity of the pendent acidic group and lipophilicity), concentration of the collector, and pH of the aqueous solution are assessed. A monoethyl lariat ether phosphonic acid collector is found to exhibit high Cd(II)/Zn(II) flotation selectivity under certain conditions.

Application of a horizontal subsurface flow constructed wetland on treatment of dairy parlor wastewater.

Two horizontal subsurface flow reed beds of 75 m(2) each, treating dairy parlor effluent and domestic sewage (about 6.5 m(3)/day), were set-up to determine the efficiency of this system in reducing the polluting load in an isolated mountain rural settlement.A total suspended solids value of about 0.70 g/l and chemical oxygen demand (COD) and biological oxygen demand (BOD(5)) values of about 1200 and 450 mg/l O(2), respectively, were characteristic of the influent waters. Removal of suspended solids and organic load constantly remained at levels above 90%, while those of the nutrients N and P were about 50% and 60%, respectively. The total number of coliform bacteria and Escherichia coli was reduced by more than 99%, and faecal streptococci by more than 98%. Nitrates, chlorides, sulfates, anionic and non-ionic surface-active agents and heavy metals were detected only in low concentrations. Concentration and localization of metals was also quantified in Phragmites tissues by microanalysis.Results demonstrated the use of reed beds as an appropriate treatment to reduce pollutants in wastewater from rural activities to values acceptable for discharge into surface waters.

Ion Flotation of Zinc(II) and Cadmium(II) in the Presence of Side-Armed Diphosphaza-16-Crown-6 Ethers

Competitive flotation of zinc(II) and cadmium(II) ions from dilute aqueous solutions by side-armed lariat ether-type derivatives of diphosphaza-16-crown-6 ethers in the presence of nonylphenol nonylethylene glycol ether as the non-ionic foaming agent has been investigated. The influence of the type of group attached to the PNP-lariat ether molecule on the selectivity and efficiency of Zn(II) and Cd(II) ion flotation is studied. An effect of alkali metal cations, i.e., Li+ and Na+, on Cd(II) ion-flotation removal is also reported. It was shown that the removal of Cd2+ increases with increase of pH values and decreases with alkali metal cations concentration increase in aqueous solutions. The correlation between selectivity coefficients of Cd(II)/Zn(II) and pH of aqueous solution as well as molar intrinsic volume and hydrophilic–lipophilic balance of studied ethers was found.

Proteomic analysis of rat brain tissue: comparison of protocols for two-dimensional gel electrophoresis analysis based on different solubilizing agents.

The present study reports a comparison of recently described solubilizing methods, to set up a simple protocol for obtaining two-dimensional (2-D) gel electrophoresis maps of brain tissue. Different protocols were used for preparing rat brain homogenates and the resulting maps were compared by image analysis. Three different detergents, two delipidation methods, and introduction of a fractionation step based on different protein solubility in surfactants, were evaluated. When using efficient zwitterionic detergents (3-[(3-cholamidopropyl)dimethylamino]-1-propanesulfonate, CHAPS; amidosulfobetaine 14, ASB-14), the patterns obtained by direct loading of total extracts were qualitatively overlapping with patterns obtained from fractionated samples. In contrast, a weaker nonionic agent (Nonidet P-40, NP-40) produced a different protein pattern in the collected fractions. Delipidation did not improve the results for all the different extraction methods. Immunoblots performed with antibodies recognizing cytosolic and membrane-spanning proteins, which were detected as nondegraded spots, showed that membrane proteins with intermediate molecular mass could be recovered. We suggest, as a simple and efficient method for preparing rat brain maps, the homogenization in a solution containing an efficient zwitterionic surfactant, which allows to solubilize cytosolic and membrane proteins in a single step. Alternatively, a fractionation can be carried out on samples homogenized by a weak solubilizing agent, a more labor-intensive effort resulting in a larger number of proteins on two maps.

Temperature Effects on the Gas Hold-up in Agitated Vessels

Previous work found the gas hold-up in a tall, 0.15 m3 vessel, agitated by three impellers, to decrease considerably with temperature. This was attributed to a decrease in liquid viscosity, a decrease in surface tension or a decrease in gas density. The aim of this work was to investigate the influence of gas density on the gas hold-up. First of all, it was attempted to reproduce the data found in literature. It was shown that contaminants had a significant impact on the gas hold-up. Experiments with increasing and decreasing amounts of tap water (as the source of the contamination) found the gas hold-up to be affected by a strongly absorbing non-ionic surface active agent. Experiments in a system exhibiting low conductivity and low gas hold-up showed that the gas hold-up decreased by 15% for temperatures between 295 and 350K. Experiments with helium as sparging gas found that gas density does have a lowering effect on the gas hold-up. The gas hold-up did not change for temperatures above 350K, which may be due to the increased presence of micro-bubbles in a near-boiling system.

A nonionic amphiphile agent promotes gene delivery in vivo to skeletal and cardiac muscles.

Direct injection of naked DNA into skeletal or cardiac muscle induces detectable gene expression. Although this provides a practical system for transgene expression, the reported efficacy is too low to confer a therapeutic benefit. By following a rational strategy based on the supramolecular structures adopted by active complexes, we have discovered a novel nonionic amphiphile synthetic agent [poly(ethyleneoxide)(13)-poly(propyleneoxide)(30)-poly(ethyleneoxide)(13) block copolymer; PE6400] that enables gene expression in up to 35% of muscle fibers from mouse tibial cranial muscle. PE6400 abolishes the ceiling effect on transgene expression of increasing amounts of naked DNA and permits long-term expression of the beta-galactosidase reporter gene in immunologically tolerant transgenic rats. This improvement in gene expression over naked DNA was observed irrespective of the reporter gene, ranging from 0.7 to 3.4 kb, and of the animal model used. In skeletal muscle, the PE6400 formulation led to a level of transfection efficiency similar to that obtained by electrotransfer. PE6400 also promotes high transgene expression in cardiac muscle. In contrast, PE6400-DNA formulations were inefficient in vitro in established cell lines and in isolated cardiomyocytes. When microinjected into the cell cytoplasm, PE6400 promotes DNA trafficking into the nucleus and induces gene expression. PE6400 provides a simple gene delivery system for skeletal and myocardial gene transfer. We propose that the PE6400 formulation could serve for the treatment of diseases primarily affecting muscle or for the expression of therapeutic proteins for local or systemic benefit.

Local tissue toxicity in response to extravascular extravasation of magnetic resonance contrast media.

The relative toxicities of the gadolinium chelates currently available in the United States were compared when extravasated in soft tissue. The increasing use of these contrast agents in higher volumes and at faster injection rates, often with a power injector, was a principal motivation for this research. Gadopentetate dimeglumine (Magnevist), gadoteridol (ProHance), gadodiamide (Omniscan), and gadoversetamide (Optimark) were evaluated at standard concentration and compared with a control (physiologic saline) and the conventional ionic radiographic contrast medium meglumine diatrizoate (Renografin 60). Each mouse received a subcutaneous injection in the hindlimb of 0.3 mL of contrast or saline. There were 6 experimental groups, with 15 animals in each group. The individual performing the injection was blinded to the identity of the contrast agent used in each mouse. After 48 hours, the mice were killed and tissue samples obtained for histopathology. A veterinary pathologist, also blinded to the agent injected, graded the degree of damage seen on microscopic examination. Of the four MR contrast agents, gadopentetate dimeglumine caused the greatest tissue damage, and gadoteridol and gadodiamide-the two lowest osmolar agents-the least. The difference was statistically significant in terms of both inflammation (P = 0.0008 for gadoteridol, and P = 0.006 for gadodiamide) and necrosis (P = 0.0067 for gadoteridol, and P = 0.031 for gadodiamide), when these agents were compared with gadopentetate dimeglumine. In regard to the control experiments, for all three variables (necrosis, edema, and inflammation), there was no statistically significant difference between the results with gadoteridol or gadodiamide and those with saline. In terms of both edema and inflammation, the effect of gadopentetate dimeglumine, although less, could not be differentiated with any statistical significance from that of meglumine diatrizoate. Gadoversetamide, which has an osmolality between the ionic agent (gadopentetate dimeglumine) and the other two nonionic agents, caused a reaction that could not be differentiated from that seen with gadopentetate dimeglumine for both necrosis and edema. Only in the scoring of inflammation was the effect less using gadoversetamide compared to gadopentetate dimeglumine with any statistical significance (P = 0.021). The risk of tissue damage due to extravasation is not widely appreciated for the gadolinium chelates. Care should be exercised during contrast injection, to avoid inadvertent extravasation and its deleterious consequences, in particular with the two higher osmolar agents (gadopentetate dimeglumine and gadoversetamide).

Molecular Design of Antifungal Agents

In a rational approach to the design of antifungal agents against Saccharomyces cerevisiae, a series of alkyl gallates (3,4,5-trihydroxybenzoates) were synthesized and assayed. Nonyl gallate (1) was found to be the most effective with a minimum fungicidal concentration (MFC) of 12.5 microg/mL (42 microM), followed by octyl gallate (2) with an MFC of 25 microg/mL (89 microM). These MFCs are little influenced by pH values. A time-kill curve study indicates that nonyl gallate exhibits fungicidal activity against S. cerevisiae at any growing stage. The antifungal activity of nonyl gallate is due primarily to its ability to act as a nonionic surface-active agent (surfactant). The length of the alkyl group is not a major contributor but plays a role in eliciting the activity to a large extent. As far as alkyl gallates are concerned, their antimicrobial spectra and potency depend largely on the hydrophobic portion of the molecules.

Bacterial target sites for biocide action

Although biocides have been used for a century, the number of products containing biocides has recently increased dramatically with public awareness of hygiene issues. The antimicrobial efficacy of biocides is now well documented; however, there is still a lack of understanding of their antimicrobial mechanisms of action. There is a wide range of biocides showing different levels of antimicrobial activity. It is generally accepted that, in contrast to chemotherapeutic agents, biocides have multiple target sites within the microbial cell and the overall damage to these target sites results in the bactericidal effect. Information about the antimicrobial efficacy of a biocide (i.e. the eta-value) might give some useful indications about the overall mode of action of a biocide. Bacteriostatic effects, usually achieved by a lower concentration of a biocide, might correspond to a reversible activity on the cytoplasmic membrane and/or the impairment of enzymatic activity. The bacteriostatic mechanism(s) of action of a biocide is less documented and a primary (unique?) target site within the cell might be involved. Understanding the mechanism(s) of action of a biocide has become an important issue with the emergence of bacterial resistance to biocides and the suggestion that biocide and antibiotic resistance in bacteria might be linked. There is still a lack of understanding of the mode of action of biocides, especially when used at low concentrations (i.e. minimal inhibitory concentration (MIC) or sublethal). Although this information might not be required for highly reactive biocides (e.g. alkylating and oxidizing agents) and biocides used at high concentrations, the use of biocides as preservatives or in products at sublethal concentrations, in which a bacteriostatic rather than a bactericidal activity is achieved, is driving the need to better understand microbial target sites. Understanding the mechanisms of action of biocides serves several purposes: (i) it will help to design antimicrobial formulations with an improved antimicrobial efficacy and (ii) it will ensure the prevention of the emergence of microbial resistance.

Antifungal activity of octyl gallate

Antifungal activities of propyl (C 3), octyl (C 8) and dodecyl (C 12) gallates (3,4,5-trihydroxybenzoate) were tested against Saccharomyces cerevisiae ATCC7754 and Zygosaccharomyces bailii ATCC 60483. Octyl gallate was found to be the only active compound with the minimum fungicidal concentration of 25 μg/ml (89 μM) against S. cerevisiae and of 50 μg/ml (177 μM) against Z. bailii, respectively. The inactivation study showed that octyl gallate was fungicidal against both S. cerevisiae and Z. bailii at any stage of growth. These fungicidal activities were not influenced by pH values. Octyl gallate at 100 μg /ml reduced plasma membrane fluidity to 48% of control. On the other hand, dodecyl gallate at the same concentration reduced it to 76% of control. Only octyl gallate inhibited glucose-induced medium acidification, indicating direct or indirect inhibition of plasma membrane H +-ATPase. The primary fungicidal activity of octyl gallate comes from its ability to act as a nonionic surface-active agent (surfactant), though it can not be inferred that membrane damage, such as a decrease in the membrane fluidity, is the only cause of the lethal effect.

Evaluation of pluronic polyols as carriers for grafting materials: study in rat calvaria defects.

Pluronic polyols are a family of non-ionic surfactants currently used as drug carriers for antibiotic, anti-inflammatory, and anti-neoplastic agents. Therapeutic administration of non-ionic surface-active agents is known to facilitate early collagen synthesis and microcirculation, thus promoting wound healing. The purpose of this study was to determine the in vivo effects of pluronic polyols combined with either an allograft or an alloplast on the healing of critical-sized calvarial defects. One hundred fifty (150) adult (95 to 105 days old) male Sprague-Dawley rats weighing between 375 and 425 g were randomly and evenly assigned to each of 15 separate treatment groups and anesthetized, and 8 mm calvarial critical-sized defects were created. Pluronic F-68 (F-68) or pluronic F-127 (F-127) was administered either topically or systemically and in conjuction with demineralized bone powder (DBP), tricalcium phosphate (TCP), or non-grafted controls. Pluronic polyols are easily mixed with either DBP or TCP to improve handling ease. Calvaria were harvested at 12 weeks postsurgery and evaluated histomorphometrically, by contact radiography with subsequent densitometric analysis, through energy spectrometry utilizing a scanning electron microscope, and by fluorescent microscopy. There was a significant difference in the percentage of bone fill among the control, TCP, and DBP only groups, P <0.05. The only significant difference within any of these groups was between the TCP control and TCP plus systemic F-127, P<0.05. Although there were isolated differences, the overall trend was that the pluronic polyol and the mode of administration did not result in a significant change in bone wound healing as measured by the percentage of bone fill. Pluronic polyols may be considered as carriers for osseous graft materials.

Trends in Adverse Events from Iodinated Contrast Media

Documentation of adverse events associated with contrast material administration began in the Genitourinary (GU) Section in 1985 and included all computed tomography (CT) scanners by 1988. Only ionic contrast material was used in 1985 and 1986. From 1987 through 1990, both ionic and nonionic agents were being administered by selective use. As of 1991, all intravenous (IV) contrast media administration was nonionic. Adverse events were reported on a standardized form requesting information about the nature of the event and treatment given, the name and amount of contrast material administered, and patient identification. Data collection regarding extravasation of contrast material was added starting in 1993. Data collection regarding gadolinium-based magnetic resonance imaging (MRI) contrast agents also began in 1993. Adverse reactions that were categorized as allergylike include sneezing/nasal congestion, hives/itching/rash/ swelling, laryngeal edema, bronchospasm, pulmonary edema, and anaphylaxis. Other reactions included shaking/chills/fever, seizure, numbness, and malaise/achiness. With the administration of ionic contrast media, nausea/ vomiting and arm pain were also reported. Reactions were graded as mild when no therapy was required, as moderate when therapy was given and the patient was sent home from the radiology department, and as severe when urgent therapy was required and the patient was subsequently followed in the emergency room or admitted to the hospital.

Trends in adverse events after IV administration of contrast media.

Data collected from 1985 to 1999 on adverse events after the IV administration of contrast media were evaluated to identify trends. Data collected on 391 adverse events after 90,473 administrations of iodinated contrast media and 19 events after 28,340 administrations of gadolinium were evaluated. Reactions were graded as mild, moderate, or severe. Data were also collected regarding contrast extravasation. When only ionic iodinated contrast material was used, the adverse reaction rate was 6-8%. With the selective use of contrast material, the adverse reaction rate was 0.6% and 0.7%, respectively, for ionic and nonionic agents. The rate decreased to 0.2% with the universal use of nonionic agents. More than 90% of adverse reactions were allergic-like. Seven severe reactions (0.05%) and no deaths occurred in the ionic group. During the selective use period, one death occurred in the nonionic group. No severe reactions or deaths occurred during the first 5 years of universal nonionic use. Since then, 10 severe reactions (0.02%) and one death have occurred. Seven reactions occurred in patients after helical CT angiography. The extravasation rate for iodinated contrast material has remained constant at 0.3-0.4% annually. The adverse reaction rate to gadolinium contrast material was 0.06%. Mild and moderate adverse events are more common with ionic contrast material than with nonionic. Most reactions are allergic-like. Severe reactions are seen equally with ionic and nonionic contrast material but differ in type. The reactions were allergic-like in the ionic group but were predominantly attributable to cardiopulmonary decompensation in the nonionic group. Helical CT angiography may play a role in reactions.

FLOTATION OF Co(II), Sr(II), AND Cs(I) CATIONS WITH PROTON-IONIZABLE LARIAT ETHERS

An experimental investigation is presented on flotation of Co(II), Sr(II), and Cs(I) cations from very dilute aqueous solutions with proton-ionizable crown ethers: monoethyl sym-(butyl)dibenzo-16-crown-5-oxymethylphosphonic acid, sodium 3-[sym-(decyl) dibenzo-16-crown-5-oxy]propanesulfonate, and sym-(decyl) dibenzo-16-crown-5-oxyacetic acid, used separately or together with a nonionic foaming agent (Triton X-100). The effect of major process variables on both the efficiency and the rate of flotation of Sr(II) cations with sym-(decyl)dibenzo- 16-crown-5-oxyacetic acid and Triton X-100 were established. Moreover, the competitive Sr2+/Cs+ flotation was studied with sulfonic and carboxylic 16-crown-5 derivatives. The carboxylic collector exhibited strong affinity towards Sr(II) cations and up to 1000-fold molar excess of lithium, ammonium, and potassium chlorides, and nitrates did not stop flotation of Sr(II) cations. Such affinity allowed for complete separation of Sr2+ from Cs+ in a single-stage batch flotation. Selectivity of flotation of Sr(II), Cs(I), and Co(II) cations with the sulfonic and carboxylic collectors did not follow the “crown ether cavity size” selectivity rule. Nevertheless, the separation of Sr and/or both Sr with Cs from extremely dilute aqueous solutions with these collectors was efficient and fast, which might have a practical meaning for the decontamination of aqueous solutions containing radioactive isotopes. Proton-ionizable crown ether derivatives of sufficient surface activity and water solubility could make a new generation of specific collectors for flotation of aqueous ions.

Early and late reactions after the use of iopamidol 340, ioxaglate 320, and iodixanol 320 in cardiac catheterization

Background Although modern contrast agents have tolerability superior to older agents, significant differences remain between the agents currently in use. Methods To investigate the incidence of early (<24 hours) and late (>24 hours to 7 days) reactions to 3 contrast agents commonly used in cardiac catheterization, we performed a randomized, prospective, double-blind trial in which 2001 patients received one of the following agents: iopamidol 340, a nonionic monomer; ioxaglate 320, an ionic dimer; and iodixanol 320, a nonionic dimer. Possible reactions to contrast were recorded during the hospital admission and after discharge by means of a questionnaire, telephone follow-up, or both. Results Early reactions occurred in 22.2% of those receiving ioxaglate, 7.6% of those receiving iodixanol, and 8.8% of those receiving iopamidol (P <.0001). Late skin reactions occurred in 12.2% of those receiving iodixanol, 4.3% of those receiving ioxaglate, and 4.2% of those receiving iopamidol (P <.0001). Conclusions The early side effect profile of certain ionic contrast agents suggests that these agents should no longer be used routinely in cardiac catheterization. The use of nonionic agents, however, is associated with late skin reactions, but there are notable differences between the monomeric and dimeric compounds. Although the skin reactions are generally benign, this is not always the case. Patients should be advised accordingly. (Am Heart J 2001;141:677-83.)

Antifungal activity of octyl gallate: structural criteria and mode of action

Octyl gallate (3,4,5-trihydroxybenzoate) was found to possess antifungal activity against Saccharomyces cerevisiae and Zygosaccharomyces bailii, in addition to its potent antioxidant activity. Catechol moiety is essential to elicit this activity. The primary fungicidal activity of octyl gallate comes from its ability to act as a nonionic surface-active agent (surfactant). The length of the alkyl chain is not a major contributor but plays an important role in eliciting the activity.

Inhibition effect of some surface active agents on dissolution of copper in nitric acid

AbstractThe inhibitive efficiency of some nonionic, amphoteric, cationic, and anionic surface active agents (surfactants) on the dissolution of copper in 4·5M HNO3 was studied at 25°C by the weight loss method. The percentage inhibition I increases as the concentration of the cationic, nonionic, and amphoteric substances increases and reaches a limiting value. It is suggested that this is due to the formation of a monolayer on the surface of the metal; the Langmuir adsorption isotherm was confirmed. In the case of anionic surface agents, the percentage inhibition values were at their highest at low surfactant concentrations and decreased as the concentration of the surfactant increased.

RENAL EFFECTS OF CARDIAC ANGIOGRAPHY WITH DIFFERENT LOW-OSMOLAR CONTRAST MEDIA

The aim of this study was to evaluate the renal effects of cardiac angiography performed with three low-osmolar contrast media (CM): iopromide (IPR), ioversol (IVR) and ioxaglate (IOX). IPR and IVR are non-ionic CM, IOX is an ionic CM. Different parameters of renal function were determined before and 6, 24, 48, 72 hrs after angiography in 45 patients: 15 patients were examined with IPR, 15 with IVR and 15 with IOX. Glomerular effects – Plasma creatinine increased slightly at the 24th hour after IVR and IOX and at 48 hours after IOP. A significant increase in plasma β2-microglobulin was observed, at the same time, only after IOX. A significant decrease in creatinine clearance was found at 6 hours after IOX. No significant variations in glomerular filtration rate (GFR) and in effective renal plasma flow were found at 48 hours after cardiac angiography; while filtration fraction was significantly reduced after IOP and IOX. Tubular effects – A marked decrease in sodium clearance and a relevant increase of urinary activities of different tubular enzymes were found after cardiac angiography with all CM, but were more evident after the ionic CM IOX, than after the two non-ionic agents. These tubular effects reached the maximum between 6 and 24 hours and returned to baseline within 72 hrs after cardiac angiography. In conclusion, slight glomerular effects were observed mainly after IOX. A reversible tubular malfunction was found with the three low-osmolar CM and was more evident after ionic CM IOX, thus suggesting that other mechanisms, besides osmolarity, play a role in tubular toxicity due to CM. In no patient did the glomerular and tubular effects of CM have a clinical relevance.

Preclinical profile of the monodisperse iodinated macromolecular blood pool agent P743.

To summarize the chemical synthesis, physicochemical characterization, pharmacokinetic behavior, and biological evaluation of P743, a new macromolecular iodinated contrast medium. The synthesis and molecular modeling of the iodinated macromolecule P743 are described. The pharmacokinetic profile was established in rabbits and rats. Acute toxicity in mice, renal tolerance in normal rabbits, and renal tolerance in uninephrectomized, dehydrated rats undergoing selective intrarenal injection was evaluated. In vitro permeability effects on isolated mastocytes and on the coagulation pathways were carried out. Computed tomography vascular imaging was performed after intravenous injection of P743 (300 mg I/kg) in rabbits and compared with the nonspecific nonionic agent iobitridol. P743 is a monodisperse, macromolecular iodinated contrast medium. In both rabbits and rats, P743 showed a pharmacokinetic profile consistent with that of a rapid-clearance blood-pool agent. Its diffusion through the endothelium was found to be low in vitro, thus confirming early confinement of this macromolecule, unlike nonspecific contrast media. In both species, P743 was excreted by glomerular filtration. Acute toxicity disclosed no mortality at the highest volume that could be injected into mice, leading to a median lethal dose greater than 8.9 g I/kg. Renal tolerance was found to be good in both euvolemic rabbits and uninephrectomized, dehydrated rats. No histamine or leukotriene B4 release was found on RBL-2H3 isolated mastocytes. P743 did not interfere with the coagulation pathways. Imaging experiments confirmed that P743 remains in the vascular compartment for a longer time than does iobitridol, thus allowing vascular enhancement that is twice as high as that of iobitridol in the recirculation phase. The pharmacokinetic and imaging profiles of P743, a new, monodisperse, macromolecular blood-pool iodinated contrast medium, were consistent with those of a rapid-clearance blood-pool agent. Its initial safety profile is satisfactory. Further experimental imaging studies are required to define the clinical interest in such molecules.

Agglomeration of ink particles using a mixture of a fatty acid sodium salt and a non-ionic surfactant

Studies on a model ink suspension have shown that the effect of non-ionic dispersion agents on ink agglomeration using fatty acid chemistry as collector was highly temperature-dependent. The non-io ...