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Studies on the stimulation of cAMP metabolism by heparin solutions containing benzyl alcohol.

Heparin solutions containing benzyl alcohol as a preservative increase intracellular cAMP concentrations in human lymphocytes by as much as 5 fold. Similar changes but of a lesser magnitude were also observed in human polymorphonuclear leukocytes and platelets and rabbit alveolar macrophages. Further analysis demonstrated that benzyl alcohol used as a preservative was responsible for this finding and that heparin per se had no effect on cAMP metabolism. The cAMP response to benzyl alcohol was a time- and dose-dependent process. In human peripheral blood lymphocytes, cAMP levels increased in a linear fashion over a benzyl alcohol concentration range from 0.015-0.30% (v/v). The increased cAMP concentrations in lymphocytes as measured by radioimmunoassay were not due to formation of a cross-reacting adenosine-alcohol adduct since the immunoreactive material produced was destroyed by phosphodiesterase and co-migrated with 3H-cAMP in thin layer chromatographic studies. Concentrations of benzyl alcohol which affect cAMP metabolism are commonly present in biologic studies employing heparin solutions. In view of these findings certain previously described effects of heparin may need to be reinterpreted and in the future heparin solutions containing benzyl alcohol should not be used when studying biologic processes known to be influenced by alterations in cAMP metabolism.

Animals↗
PubMed1979

Effect of the anesthetics benzyl alcohol and chloroform on bilayers made from monolayers.

The neutral anesthetics chloroform and benzyl alcohol, at concentrations that block the nerve impulse, greatly modify the transport parameters of positive and negative ions in lipid bilayers made from monolayers. Both chloroform and benzyl alcohol increase the membrane permeability to these ions and increase the translocation rate for tetraphenylborate. It was found that both anesthetics increase the membrane permeability to positive ions more markedly than to negative ions. It was also found that the membrane capacitance increases lineary with the concentration of benzyl alcohol. At 51 mM benzyl alcohol, the increase in capacitance is approximately 6%. Chloroform also increases the membrane capacitance; the increase in capacitance was found to be 6% at 18 mM chloroform. An analysis of the changes in the transport parameters of the lipophilic ions, together with the changes in membrane capacitance, suggests that benzyl alcohol and chloroform modify the dipole potential and dielectric constant of the membrane. Benzyl alcohol may also increase the "fluidity" of the lipid bilayer membranes. At 36 mM benzyl alcohol, the membrane permeability to acetamide increases by 38%.

Benzyl Alcohol↗
PubMed1979

Effect of benzyl alcohol on lipid bilayers. A comparisons of bilayer systems.

The effect of the small anesthetic molecule, benzyl alcohol, on the structure of various bilayer system has been studied by optical, electrical, and x-ray diffraction techniques. We find that the modifications in bilayer thickness caused by benzyl alcohol differ dramatically for planar (or black lipid) bilayers containing solvent, planar bilayers containing little or no solvent, and vesicular bilayers. Benzyl alcohol increases the thickness of planar bilayers containing n-alkane solvents, yet decreases the thickness of "solvent-free" planar bilayers. The effect of benzyl alcohol on vesicular bilayers below the phase transition temperature also depends on whether solvent is present in the bilayers. Without solvent, gel-state bilayers are reduced in thickness by benzyl alcohol, whereas in the presence of solvent, the thickness is unchanged. Above the phase transition temperature, benzyl alcohol has no measurable effect on vesicular bilayer thickness, whether solvent is present or not. These results indicate that different model membrane systems respond quite differently to a particular anesthetic.

Benzyl Alcohol↗
PubMed1977

Regulation of synthesis of benzyl alcohol dehydrogenase in Acinetobacter calcoaceticus NCIB8250.

Specific activity of benzyl alcohol dehydrogenase in carbon-limited continuous cultures was at a maximum at a specific growth rate of 0.2 h-1, but fell off at lower and higher growth rates. The specific activity in nitrogen-limited cultures was always lower and was inversely proportional to growth rate. There was severe repression of benzyl alcohol dehydrogenase during metabolism of L(+)-mandelate or phenylglyoxylate in batch cultures. Synthesis of benzyl alcohol dehydrogenase was followed in experiments where various compounds, including a gratuitous inducer and an anti-inducer of the mandelate enzymes, were added to uninduced or pre-induced cultures and to constitutive and blocked mutants. The results led to the conclusion that there were at least two types of repression. One was caused by phenylglyoxylate carbon-lyase (or a compound synthesized co-ordinately with it), but not by the other mandelate enzymes or by L(+)-mandelate, phenylglyoxylate, benzaldehyde or benzoate. A second type of repression was observed during rapid growth or after the addition of compound such as succinate which are rapidly and completely metabolized.

Acinetobacter↗
PubMed1975

Allergic paraben and benzyl alcohol hypersensitivity relationship of the "delayed" and "immediate" varieties.

From a review of the literature, and the results of scratch, intracutaneous and subcutaneous injections of patients with parbens and benzyl alcohol sensitivity of the delayed type characterized by allergic contact dermatitis and strongly positive patch patch tests, it would appear that such sensitivity is not usually accompanied by the immediate urticarial type of allergic sensitivity. This communication concerns itself with results of testing patients with clinical sensitivity and positive patch test reactions to the parabens or benzyl alcohol with scratch, intracutaneous and subcutaneous injections of these preservatives in order to determine the relationship of the "delayed" type of allergic hypersensitivity to the parabens and benzyl alcohol with the "immediate" variety of hypersensitivity. The parabens and benzyl alcohol are widely employed as preservatives for many allergenic extracts used in scratch and intracutaneous testing. In addition, these preservatives are used in injectable corticosteroid medicaments and in local anesthetic solutions. In order to determine whether the presence of these preservatives in allergenic extracts would produce false positive scratch or intracutaneous tests or might produce an immediate, urticarial or anaphylactic reaction in patients with allergic contact dermatitis and positive patch test reactions to these preservatives, two patients with positive patch test reactions and allergic contact dermatitis to the parabens and two with similar benzyl alcohol sensitivity were tested in the manner detailed in the following case reports.

Adrenal Cortex Hormones↗
PubMed1977

Depression of glutamate-mediated synaptic transmission by benzyl alcohol.

The data obtained from this study suggest that the nonionizable anesthetic benzyl alcohol has two prominent actions on GABA- and glutamate-mediated synaptic transmission at the lobster neuromuscular junction. They are as follows: (1) depression of the excitatory end-plate potential and the postsynaptic membrane response to applied glutamate, and (2) a hyperpolarization of the postsynaptic resting membrane potential associated with a decrease in effective membrane resistance. No change in amplitude of the inhibitory end-plate potential or inhibitory reversal potential was seen. Excitatory miniature end-plate potential frequency was also unaffected. The depression of excitatory synaptic transmission appears to be due to a decreased responsiveness of the postsynaptic receptor-ionophore complex.

Action Potentials↗
PubMed1979

Alcohol-induced switching over of metabolic flux in Streptomyces noursei JA0 3890b.

Short-chain alcohols, benzyl alcohol and Tween 20 were found capable of switching over the metabolic flux in Streptomyces noursei JA 3890b from the preference of oxidative deamination of alanine towards the reinforced acquisition of NH4+. These changes were correlated to the decrease of the ratio of saturated to olefinic fatty acids in the mycelium, suggesting that alcohols and other polar lipophilic compounds can interfere with the biosynthesis and the function of the cytoplasmic membrane in Streptomyces.

1-Propanol↗
PubMed2026

Vortex-assisted liquid-liquid microextraction based on natural deep eutectic solvents for the determination of pyrethroid pesticides in urine.

A novel, facile, and environmentally friendly analytical method was developed based on vortex-assisted liquid-liquid microextraction and high-performance liquid chromatography with diode-array detection for detecting pyrethroid pesticides (PPs) in urine. Natural deep eutectic solvents (NADESs) were prepared using plant essential oil-derived monoterpenoids (thymol, carvacrol, and menthol) combined with aromatic primary alcohols (benzyl alcohol, phenethyl alcohol, and phenylpropyl alcohol) as hydrogen bond donors and acceptors. These solvents served as environmentally benign extraction media, thereby avoiding the use of conventional volatile, toxic organic solvents. NADESs are naturally derived, easy to prepare, biodegradable, and environmentally friendly solvents. Hydrophobic and π-π interactions between the NADESs and PPs may contribute to enhancing the affinity of PPs toward the NADESs phase. Vortex technology, accelerating mass transfer between the sample and extractant phases, enables fast extraction of PPs. Under optimized conditions, the method achieved a low detection limit (0.002 mg L-1), satisfactory precision with relative standard deviations (0.3%-2.4%), and acceptable recovery (80.7%-86.2%). The method demonstrated excellent performance in urine analysis and was feasible as a facile and green strategy for monitoring the content of PPs in biological matrices and assessing exposure risk.

Liquid Phase Microextraction↗
PubMed1979

[The solubilizer of diazepam (valium)--its action on respiration (author's transl)].

Investigations carried out in volunteers showed that when compared with physiological saline the solubilizer of diazepam caused hyperventilation. Among the constituents of the solubilizer propylene glycol and ethyl alcohol have to be excluded, likely benzyl alcohol was due to the respiratory response. Benzyl alcohol has local anesthetic properties and its action on respiration has never been examined up to now. Therefore a further study was performed to compare ampoule solutions of diazepam with or without benzyl alcohol in the solubilizer used. The solutions were given intravenously, the dose of diazepam was 0.35 mg/kg, that of benzyl alcohol 1.1 mg/kg respectively. The measurements showed that solutions containing benzyl alcohol produced a statistical significant increase of respiratory rate and of minute volume. In case of intravenous administration of Valium using ampoule solutions diazepam and in addition a second active substance are applicated. The latter defined as benzyl alcohol has stimulating effects on respiration.

Adult↗
PubMed1978

The interaction of short-chain aralkyl alcohols and amines with the erythrocyte membrane.

Erythrocytes in isotonic saline are hemolyzed by benzyl alcohol and by 2-phenylethanol, but not by the corresponding amines nor by the ring-or side-chain-hydroxylated analogs. All these compounds could however interact with the erythrocyte membrane since: a) they facilitated the hemolytic effect of benzyl alcohol and/or of phenylelytic effect of benzyl alcohol and/or of phenylethanol; b) they exerted a protective effect against controlled hypotonic hemolysis.

Alcohols↗
PubMed1975

Acid-base catalysis in the yeast alcohol dehydrogenase reaction.

The effect of pH on steady state kinetic parameters for the yeast alcohol dehydrogenase-catalyzed reduction of aldehydes and oxidation of alcohols has been studied. The oxidation of p-CH3 benzyl alcohol-1,1-h2 and -1,1-d2 by NAD+ was found to be characterized by large deuterium isotope effects (kH/kD = 4.1 plus or minus 0.1) between pH 7.5 and 9.5, indicating a rate-limiting hydride trahsfer step in this pH range; a plot of kCAT versus pH could be fit to a theoretical titration curve, pK = 8.25, where kCAT increases with increasing pH. The Michaelis constnat for p-CH3 benzyl alcohol was independent of pH. The reduction of p-CH3 benzaldehyde by NADH and reduced nicotinamide adenine dinucleotide with deuterium in the 4-A position (NADD) cound not be studied below pH 8.5 due to substrate inhibition; however, between pH 8.5 and 9.5, kCAT was found to decrease with increasing pH and to be characterized by significant isotope effects (kH/kD = 3.3 plus or minus 0.3). In the case of acetaldehyde reduction by NADH and NADD, isotope effects were found to be small and exxentially invariant (kH/kD = 2.O plus or minus 0.4) between pH 7.2 and 9.5, suggesting a partially rate-limiting hydride transger step for this substrate; a plot of kCAT/K'b (where K'b is the Michaelis constant for acetaldehyde) versus pH could be fit to a titration curve, pK = 8.25. The titration curve for acetaldehyde reduction has the same pK but is opposite in direction to that observed for p-CH3 benzyl alcohol oxidation. The data presented in this paper indicate a dependence on different enzyme forms for aldehyde reduction and alcohol oxidation and are consistent with a single active site side chain, pK = 8.25, which functions in acid-base catalysis of the hydride transfer step.

Alcohol Oxidoreductases↗
PubMed1975

Effect of pH on the liver alcohol dehydrogenase reaction.

New transient kinetic methods, which allow kinetics to be carried out under conditions of excess substrate, have been employed to investigate the kinetics of hydride transfer from NADH to aromatic aldehydes and from aromatic alcohols to NAD+ as a function of pH. The hydride transfer rate from 4-deuterio-NADH to beta-naphthaldehyde is nearly pH independent from pH 6.0 to pH 9.9; the isotope effect is also pH independent with kappa-H/kappaD congruent to 2.3. Likewise, the rate of oxidation of benzyl alcohol by NAD+ changes little with pH between pH 8.75 and pH 5.9; the isotope effect for this process is between 3.0 and 4.4. Earlier substituent effect studies on the reduction of aromatic aldehydes were consistent with electrophilic catalysis by either zinc or a protonic acid. The pH independence of hydride transfer is consistent with electrophilic catalysis by zinc since such catalysis by protonic acid (with a pK between 6.0 and 10.0) would show strong pH dependence. However, protonic acid catalysis cannot be excluded if the pKa of the acid catalyst in the ternary NADH-E-RCOH complex were smaller than 6.0 or smaller than 10.0. The two kinetic parameters changing significantly with pH are the kinetic binding constant for ternary complex formation with aromatic alcohol and the rate of dissociation of aromatic alcohols from enzyme. This is consistent with base-catalyzed removal of a proton from alcohol substrated and consequent acid catalysis of protonation of a zinc-alcoholate complex. The equilibrium constant for hydride transfer from benzaldehyde to benzyl alcohol at pH 8.75 is K-eq equals kappa-H/kappa-H equals 42; this constant has important consequences concerning subunit interactions during liver alcohol dehydrogenase catalysis.

Alcohol Oxidoreductases↗
PubMed1977

Conduction-blocking concentrations of anesthetics increase with nerve axon diameter: studies with alcohol, lidocaine and tetrodotoxin on single myelinated fibers.

The equilibrium blocking concentrations of benzyl alcohol, lidocaine and tetrodotoxin just sufficient to block nerve impulse conduction were determined on myelinated single fibers of the bullfrog. For all three anesthetics it was found that the fastest conducting fibers (45 m/sec; about 18 micron diameter) required about 4 times higher blocking concentrations than the slowest fibers (8 m/sec; about 3 micron diameter). The drugs did not affect the frog sciatic nerve length constant (2 mm), using tetrodotoxin to block the action potential. In agreement with Uehara's single fiber study using urethane (Uehara, Y.:Jap. J. Physiol. 10: 267-274, 1960), it is concluded that smaller myelinated fibers are more sensitive to anesthetic blockade.

Action Potentials↗
PubMed1978

Effect of pH on the process of ternary-complex interconversion in the liver-alcohol-dehydrogenase reaction.

1. Kinetic relationships referring to multiple-turnover conditions have been derived for the slowest exponential transient appearing in two-substrate enzyme reactions proceeding by an ordered ternary-complex mechanism. The validity of these and previously derived theoretical relationships for this mechanism has been tested by application to the liver alcohol dehydrogenase reaction. 2. All essential features of the transient-state kinetics of alcohol oxidation by NAD+ in the liver alcohol dehydrogenase system can be qualitatively and quantitatively explained in view of the compulsory-order mechanism in the proposed scheme. There is no kinetic evidence for any half-of-the-sites reactivity of the enzyme. A consistent set of rate constants is reported for the enzymic oxidation of benzyl alcohol at pH 8.75. 3. Transient-state rate parameters for benzyl alcohol/benzaldehyde catalysis by liver alcohol dehydrogenase have been determined at different pH. The interpretation of such rate parameters is critically discussed with reference to their informative value for the purpose of determination of rate constants (k and k') for the process of ternary-complex interconversion in the proposed scheme. It is concluded that the apparent rate constant (k') for hydride transfer from benzyl alcohol to NAD+ is dependent on a proton dissociation step with a pKa of 6.4, whereas the rate constant (k) for hydride transfer from NADH to benzaldehyde exhibits no corresponding dependence on proton association. 4. The asymmetric pH dependence of the forward and reverse rate of ternary-complex interconversion during liver alcohol dehydrogenase catalysis appears to reflect an obligatory step of alcohol/alcoholate ion equilibration occurring at the ternary-complex level. It is suggested that the observed pKa 6.4 dependence of the transient rate of alcohol oxidation can be attributed to a coupled acid-base system involving minimally the enzyme-bound alcohol and the protein residues Ser-48 and His-51.

Alcohol Oxidoreductases↗