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PubMed2006

Fate and effect of quaternary ammonium compounds on a mixed methanogenic culture.

The potential inhibitory effect of four quaternary ammonium compounds (QACs) and Vigilquat, a commercial sanitizer which is a mixture of the four QACs, was investigated at concentrations up to 100 mg/L using a mixed, mesophilic (35 degrees C) methanogenic culture. Dextrin and peptone were used as the carbon and energy sources. A batch assay conducted at a range of QAC concentrations showed that QACs were inhibitory to methanogens at and above 25 mg/L. Methanogenesis was more susceptible to QAC inhibition than acidogenesis. Adsorption of QACs on biomass was successfully simulated with the Freundlich isotherm equation. The inhibitory effect of Vigilquat on the mixed methanogenic culture was also investigated in a batch reactor fed with dextrin and peptone. Methanogens were inhibited when the total QAC concentration reached 30 mg/L and volatile fatty acids (VFAs) accumulated. However, methane production recovered in 57 days of incubation, and all VFAs were consumed, suggesting that a prolonged incubation period is necessary for the methanogens to overcome the transient inhibition at a relatively low QAC concentration. None of the QACs tested in this study was biodegraded under methanogenic conditions.

Adsorption↗
PubMedDate not supplied

[Role of the hydrophobicity of polymethylene-bis-quaternary ammonium compounds in the mechanism of their curare-like action].

Lengthening of the N-alkyl radical (from--C2H5 to C10H21) in the series of polymethylene-bis-quaternary ammonium compounds was found to result in an increased hydrophobic properties of the compounds. In the presence of the N-butyl radical the mode of the action exerted by the substances changes, viz. from depolarizing they turn into antidepolarizing ones. A substitution of polyalicyclic radicals (cyclohexyl, 1-adamantyl) for methyl groups at the nitrogen atoms in the series of polymethylene-bis-quaternary ammonium compounds proved that in order to changed the mode of action hydrophobic properties of the cyclohexyl radicals appear to be good enough.

Animals↗
PubMed1976

The pharmacological actions of some polymethylene-bis-(hydroxyethyl)-dimethyl-ammonium compounds on cholinergic transmission.

Some polymethylene-bis-(hydroxyethyl)-dimethyl-ammonium (dicholine) compounds containing from 7 to 10 methylene groups between the quaternary nitrogen atoms, have been studied for activity at various sites of cholinergic transmission. The post-junctional activity of the compounds was investigated on the frog rectus abdominis muscle. Small doses of C8-, C9-, and C10-dicholine potentiated ACh contractions, however larger doses of all the dicholine compounds blocked the nicotinic receptor sites of the frog rectus muscle. The dicholine compounds blocked neuromuscular transmission in the rat phrenic nerve diaphragm. These actions at the rat neuromuscular junction are compared with the purely post-junctional actions on the frog rectus muscle. Although the compounds exert anticholinesterase activity in vitro it is suggested that this effect plays little part in the action of the drugs at the neuromuscular junction. It is concluded that the dicholine compounds have both pre- and post-junctional activity at the neuromuscular junction. The dicholine compounds are acetylated at varying rates by partially purified choline acetyltransferase (ChAc) although all are acetylated less readily than choline. The rate of acetylation of the dicholine compounds by ChAc parallels their activity in blocking neuromuscular transmission and it is suggested that other quaternary ammonium compounds containing hydroxyl or hydroxyethyl groupings may be acetylated by ChAc and this may affect their blocking action at the neuromuscular junction.

Acetylation↗
PubMed2004

Adjuvant effect of quaternary ammonium compounds in a murine model.

It has been suggested that occupational exposure to quaternary ammonium compounds (QACs) may promote the development of allergic airway diseases. In this study, hazard identifications of the adjuvant effect of cetylpyridinium chloride (CPC), dimethyldioctadecylammonium bromide (DDA), hexadecyltrimethylammonium bromide (HTA), and tetraethylammonium chloride (TEA) were performed in a screening bioassay. Female BALB/c mice were injected subcutaneously with the model allergen ovalbumin (OVA) alone or together with different quantities of one of the QAC test compounds. After one or two boosters, levels of OVA-specific IgE, IgG1 and IgG2a antibodies were measured in sera. CPC and DDA increased IgE and IgG1 antibody production, respectively, compared to the OVA control group, whereas HTA and TEA showed no adjuvant effect. Nevertheless, when TEA was given in combination with DDA, the adjuvant effect was up to six-fold higher than the adjuvant effect of DDA alone. Only DDA had a statistically significant adjuvant effect on IgG2a antibody levels.

Adjuvants, Immunologic↗
PubMedDate not supplied

Diquaternary ammonium compounds as transfection agents.

Diquaternary ammonium salts constitute a new class of reagent for mediating transfection of DNA in mammalian cell lines. N,N'-dioleyl-N,N,N',N'-tetramethyl-1,2-ethanediamine (TmedEce), N,N'-dioleyl-N,N,N',N'-tetramethyl-1,3-propanediamine (PropEce), N,N'-dioleyl-N,N,N',N'-tetramethyl-1,6-hexanediamine (HexEce), and their corresponding N,N'-dicetyl saturated analogues (TmedAce, PropAce and HexAce) have all been synthesized and characterized. They were prepared via a bis-Menshutkin reaction of the corresponding tetramethyldiamine with 2.2 M equiv of a long-chain alkyl halide (saturated or unsaturated). The reaction was run in anhydrous acetonitrile for ca. 3 days at 60 degrees C, which produced the diquaternary ammonium halides in good to nearly quantitative yields for most derivatives. DNA transfection comparable to commercially available reagents such as Lipofectin, Lipofectace, Lipofectamine, and O-ethyldioleoylphosphatidylcholinium triflate has been achieved in vitro with these new reagents. There was no need to use a colipid for effective transfection, but serum did significantly inhibit transfection. The saturated and the unsaturated derivatives differed with respect to hydration behavior. The saturated derivatives appeared to retain a lamellar-type crystalline array structure upon hydration, whereas the unsaturated versions formed micelles and/or liposomes, depending on the ionic strength: HexEce was micellar in both water and saline; PropEce was micellar in water but lamellar in saline; and TmedEce was lamellar in both. Despite these different hydration patterns, all of these unsaturated derivatives formed productive transfection complexes with DNA. Varying the distance between the quaternary sites affected transfection efficacy in the order HexAce > TmedAce = PropAce for the saturated derivatives and in the order PropEce = HexEce > TmedEce, with a smaller spread, for the unsaturated derivatives.

Animals↗
PubMed1997

Effects of quaternary ammonium compounds with 0.1% sodium hydroxide on swine vesicular disease virus.

The effects of quaternary ammonium compounds (QACs) with sodium hydroxide on swine vesicular disease virus (SVDV), an enterovirus were studied. Didecyldimethylammonium chloride (DDAC) with 0.1% NaOH showed a stronger effect against SVDV than other QACs with 0.1% NaOH. The effect of DDAC with 0.1% NaOH was strong at 40 degrees C. DDAC was effective against SVDV at pH values around 11.0, but not in the distilled water control. The effect of DDAC with 0.1% NaOH was already observed at 1 min after mixing of the DDAC with SVDV. Observation under an electron microscopy revealed that the probable mechanism of inactivation of DDAC with 0.1% NaOH is as follows: The virus particles were partially destroyed by 0.1% NaOH. DDAC gathered these affected particles and formed a micelle, then SVDV lost its infectivity. From these results, QACs with 0.1% NaOH are considered to be very effective against SVDV representing enteroviruses.

Animals↗
PubMedDate not supplied

Application of the rough sets theory in structure activity relationship of antielectrostatic ammonium compounds.

The relationships between the chemical structure and the antielectrostatic effect of 112 ammonium compounds were analysed using the method of rough sets. The antielectrostatic activity was determined by measurements of the maximum voltage induced. Using the rough sets approach the smallest set of condition attributes significant for high quality of classification has been found. The resulting decision rules describe relations between the structure and the antielectrostatic properties of ammonium chlorides in terms of significant condition attributes. This may be helpful in predicting the structures of the new antielectrostatic compounds to be synthesized.

Quaternary Ammonium Compounds↗
PubMed2006

Virucidal activity of a quaternary ammonium compound disinfectant against feline calicivirus: a surrogate for norovirus.

BACKGROUND: Norovirus, formerly known as Norwalk virus, is an important cause of gastroenteritis outbreaks in hospitals, food services, schools, and cruise ships. Infection control practices by using disinfectants to eliminate noroviruses from surfaces and environmental samples reduce the morbidity and spread of virus outbreaks. There are not many commercial disinfectants effective against norovirus. Noroviruses cannot be cultivated in vitro. However, feline calicivirus can be used as a surrogate to determine disinfectant efficacy against noroviruses. Feline calicivirus was used in a virucidal effectiveness test protocol as a surrogate for norovirus to determine the virucidal efficacy of R-82, a quaternary ammonium compound disinfectant cleaner. METHODS: Feline calicivirus suspensions containing at least 5% fetal bovine serum were dried on carriers and treated with 1:256 dilutions of R-82 disinfectant in water, with a hardness of 400 ppm as calcium carbonate, for 10 minutes. Hypochlorite concentrations of 100 +/- 10 and 1,000 +/- 10 ppm, respectively, were also analyzed as internal control standards. After contact period, the test agents were neutralized with 2 mL of appropriate neutralizer, and mixtures were scraped from carrier surfaces with a cell scraper. Selected dilutions of the neutralized inoculum/test agent mixtures were added to cultured cell monolayers of appropriate host cells. Postincubation, the infectious feline calicivirus was scored microscopically by observing virus-specific cytopathic effects produced by replicating infectious virus. The performance criterion was a minimum of 4-log(10) reduction in cytopathic effects of feline calicivirus. RESULTS: After a 10-minute contact time, formulation R-82 diluted 1:256 showed a 6.6- and 6.4-log(10) reductions in cytopathic effects of feline calicivirus during initial and confirmatory testing, respectively, demonstrating complete inactivation of the virus. A hypochlorite solution of 1,000 ppm exhibited similar log(10) reductions to the quaternary ammonium disinfectant, demonstrating the reproducibility of the protocol. CONCLUSION: Formulation R-82, a quaternary ammonium compound, is a 1-step disinfectant cleaner, which exhibited virucidal activity against feline calicivirus suspensions dried on hard surface carriers. Surfaces are vectors for virus transmission during outbreaks by transferring the virus to people or other environmental surfaces. Therefore, treatment of contaminated surfaces with formulation R-82 will optimize disinfection of noncritical and critical surfaces in health care institutions, reducing the possibility of virus transmission during outbreaks.

Animals↗
PubMed1995

Muscarinic regulation of the cardiac CFTR Cl- current by quaternary ammonium compounds.

In guinea pig ventricle, the protein kinase A-regulated Cl- current (ICl) is conducted by an alternatively spliced isoform of the cystic fibrosis transmembrane conductance regulator. We studied muscarinic regulation of this current using the whole-cell configuration of the patch-clamp technique. Acetylcholine (ACh) antagonized activation of ICl activated by 1 microM isoproterenol (ISO) in a concentration-dependent manner. The concentration of ACh that produced a half-maximal effect (K1/2) was 36 nM, the slope factor was 1.1, and the relative magnitude of the Cl- conductance at maximally effective concentrations of ACh (Gmin) was 21% of that observed in the presence of ISO alone. In the presence of 100 nM atropine, a competitive antagonist at the muscarinic receptor, the K1/2 value for ACh inhibition of ICl was increased to 4.3 microM, but the slope factor and Gmin were not affected, which indicated that the dissociation constant (KB) for atropine was < 1 nM. ACh-induced inhibition of the ISO-activated ICl was also blocked by the quaternary ammonium compound tetraethylammonium (TEA). Like atropine, TEA increased the K1/2 value for ACh inhibition of ICl without affecting the slope factor or Gmin. Schild analysis confirmed that TEA is also a competitive antagonist at the muscarinic receptor, with a KB value of 137 microM. However, tetramethylammonium (TMA), a structurally related compound, acted as an agonist at the muscarinic receptor. TMA inhibited ICl activated by 1 microM ISO with a K1/2 value of 342 microM, a slope factor of 0.87 and a Gmin value of 17%. Increasing the concentration of ISO shifted the K1/2 value for both ACh and TMA inhibition of ICl to higher concentrations and increased Gmin, without significantly affecting the slope factor. These results indicate that muscarinic regulation of ICl depends on the level of beta adrenergic stimulation in a functionally uncompetitive manner. They also suggest that TMA acts like ACh, a full agonist at the muscarinic receptor. Furthermore, we conclude that quaternary ammonium compounds, which are often used as ion substitutes and direct ion channel blockers, should be used with caution because of the significant and diverse effects they exert at muscarinic receptors.

Acetylcholine↗
PubMed1999

Identification and characterization of quaternary ammonium compound resistant staphylococci from the food industry.

The distribution of known genes conferring resistance to quaternary ammonium compounds (QACs) among different species of staphylococci isolated from the food industry was investigated. Twenty-four isolates hosting one of the genes qacA/qacB, smr, qacG or qacH, were subjected to species identification. Species determination was performed by biochemical analyses (API STAPH), comparative 16S rDNA sequence analysis and tDNA intergenic spacer length polymorphism analysis. Good correlation was obtained between the different methods. The isolates belonged to six different species of coagulase-negative Staphylococcus. The most commonly found species were Staphylococcus epidermidis and Staphylococcus saprophyticus. The results also indicated the possible spread of specific isolates of staphylococci which may reflect the dominance of certain strains in environments were QACs are used on a regular basis. The isolates were further characterized by the resistance phenotype to antimicrobial agents including antibiotics and disinfectants. Resistance to ampicillin, penicillin G and dyes was prevalent in strains harbouring the qacA or qacB genes, features also common among clinical staphylococci containing qacA/qacB. One QAC resistant strain harbouring the smr gene showed resistance to ampicillin, penicillin, tetracycline, erythromycin and trimethoprim. No enterotoxin production was detected among the QAC resistant strains.

Benzalkonium Compounds↗