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At least 19 recordsLinked to original sources

PubMed1978

Simple procedure for determining octanol--aqueous partition, distribution, and ionization coefficients by reversed-phase high-pressure liquid chromatography.

The described simple, accurate, and precise reversed-phase high-pressure liquid chromatographic procedure is in excellent agreement with 1-octanol shake-flask partition or distribution coefficients over a 3.5 log range. A chemically bonded octadecylsilane support is persilated and coated with 1-octanol. With 1-octanol-saturated buffers as mobile phases, a stable baseline (compared to 1-octanol adsorbed on silica) is obtained rapidly, and the log relative retention times are highly correlated with unit slope to log distribution or partition coefficients obtained from the classical shake-flask procedures. Only relatively basic, unhindered pyridines deviate, probably because of binding with residual silinol sites. In addition, if the apparent pKa or pKab of an ionizable compound lies within the pH operating range of the column support, the apparent pKa or pKab usually can be determined simultaneously with log P by measuring the log distribution coefficient at several pH values. The procedure gives rapid results, requires little material, and can tolerate impurities.

Chemistry, Pharmaceutical↗

PubMed1991

Effects of several selected odorants on the sodium- and potassium-dependent adenosine triphosphatase activities of two different chicken olfactory tuberinals.

The NaK-adenosine triphosphatase (ATPase)-rich nerve-ending particle preparations (B fractions) of the epithelial tissue of chicken olfactory tubercle and the olfactory main concha were isolated by differential centrifugation. These tissues were exposed to the following odorants: 2-nonanone, 1-nonanol, 1-octanol, (+)2-octanol, and (-)2-octanol. There was a significant stimulation of NaK-ATPase by 2-nonanone (1 x 10(-3) M) in the B fraction of the olfactory tubercle and olfactory main concha. The NaK-ATPase increased significantly in the B fraction response of the olfactory main concha with 1 x 10(-3) M of 1-octanol but NaK-ATPase declined significantly in the presence of 1 x 10(-3) M of 1-nonanol. Both optical and structural isomers of odorants were shown to elicit different responses in NaK-ATPase activity. It is proposed that interactions between the odorant molecules and the membrane bound NaK-ATPase complex lead to recognition of odor by chickens.

1-Octanol↗

PubMed1976

Studies on mushroom flavours 2. Flavour compounds in coprinus comatus.

In an aqueous extract of fruit bodies of Coprinus comatus 3-octanone, 3-octanol, 1-octen-3-ol, 1-octanol, 2-methyl-2-penten-4-olide, 1-dodecanol and caprylic acid were identified conclusively and n-butyric and isobutyric acids preliminarily. Amino-acids, nucleotides and sugars were also determined. A mixture of 37 compounds found in the extract had a stronger flavour than the natural extract. 3-Octanol, 1-octen-3-ol, 1-octanol and 2-methyl-2-penten-4-olide were the volatiles with the strongest flavour. Mass and IR spectra of 2-methyl-2-penten-4-olide are presented.

Agaricales↗

PubMed1976

Interactions between anesthetics and lipid mixtures. Normal alcohols.

The effects of normal alcohols up to 1-dodecanol on phase transitions in phosphatidylcholines and phosphatidylethanolamines have been studied using chlorophyll a as fluorescent probe. With the phosphatidylcholines, alcohols up to octanol cause a lowering of the transition temperature, and a broadening of the transition, whereas for dipalmitoylphosphatidylethanolamine, only a lowering of the transition is observed. The lowering of the phase transition temperature in dipalmitoylphosphatidylcholine by butanol and hexanol is close to that expected for ideal behavior, but the behavior of the longer chain alcohols becomes less ideal. The effects of these alcohols on mixtures of lipids have been studied, and they illustrate the care necessary if these plots of temperatures of onset and completion of gel phase formation are to be called "phase diagrams". The effect of 1 -octanol on mixtures of lipids is to increase the proportion of lipid present in the lipid-crystalline state. In contrast, 1-decanol causes an increase in the phase transition temperature for dimyristoylphosphatidylcholine, although it lowers the transition temperature for dipalmitoylphosphatidylcholine, and 1 -dodecanol raises the transition temperature for both of these phosphatidylcholines, although it lowers that for dipalmitoylphosphatidylethanolamine. Dodecanol appears to behave in these lipid bilayer membranes as a lipid with a phase transition temperature of ca. 55 degrees C. Anesthesia is discussed as a phenomenon of liquidus extension: alcohols up to 1 -octanol increase the proportion of lipid in the liquidus state and result in anesthesia, whereas the longer alcohols do not, and result in catalepsy.

Anesthetics↗

PubMed1992

[Interaction of myeloperoxidase and defensins with lipid monolayers].

Myeloperoxidase and defensin interaction with lipid mixtures of phosphatidylcholine and cholesterol or rat eye lens lipids were studied. The solubility of myeloperoxidase in 1-octanol and octanol was determined. It was shown that myeloperoxidase can be concentrated at the interface and is readily soluble in the membrane lipid phase. Defensins exhibit similar properties and increase, in addition, the cholesterol-rich monolayer tension. Possible consequences of highly cationic proteins adsorption on cholesterol-rich membranes are discussed.

1-Octanol↗

PubMed1977

High-pressure liquid chromatographic analysis of cimetidine, a histamine H2-receptor antagonist, in blood and urine.

A method is described for extraction of cimetidine, a histamine H2-receptor antagonist, from whole blood and urine with subsequent analysis by high-pressure liquid chromatography (HPLC). The drug is extracted from biological fluids with 1-octanol and back-extracted into dilute acid and then into a small volume of ethanol by saturation with potassium carbonate. HPLC analysis is performed on a column of 5-micrometer silica with a mixed mobile phase consisting primarily of acetonitrile. The method measures concentrations of cimetidine as low as 0.05 microgram/ml and is reproducible. Blood levels and urinary excretion data obtained with the analytical procedure are given for a group of human subjects who received 200-mg oral doses of cimetidine.

Chromatography, High Pressure Liquid↗

PubMed1978

Functional group contribution of bile salt molecules to partitioning of a quaternary ammonium N,N-dimethyl derivative of propranolol.

A quaternary ammonium N,N-dimethyl derivative of propranolol was extracted from pH 7.4 phosphate buffer into 1-octanol as ion-pairs with 12 different bile salts. The binding number, n, and the extraction constant, Ke, were determined. To obtain group contribution values of the bile salt molecule from the ion-pair extraction data, multiple linear regression analysis by the Free-Wilson technique was applied. The results showed that the fundamental premise of the functional group's contribution to the ion-pair extraction is valid. The functional groups of counterions contribute to the partitioning of the ammonium compound independently and additively in this system.

Bile Acids and Salts↗

PubMed1978

Kinetic and thermodynamic aspects of in vitro interphase transfer of tetracyclines I: influence of hydroxyl group substitution.

The influence of hydroxyl group substitution on the kinetic and thermodynamic aspects of the interphase transfer of three tetracycline derivatives was studied in a two-phase in vitro system composed of an aqueous pH 5.5 buffer and 1-octanol. Data are reported on the kinetic and thermodynamic parameters of activation, the net thermodynamic parameters for interphase transfer, and the contribution of hydroxyl group substituents to the energy changes associated with partitioning. For each derivative, deltaH, deltaS, T deltaS, and deltaF were positive with enthalpy dominating the entropic energy contribution. Introduction of a hydroxyl group at C-5 on the tetracycline nucleus promoted partitioning through an entropy-dominated decrease in the "apparent" free energy of partitioning, whereas shifting the hydroxyl group to C-6beta retarded partitioning due to an enthalpy-dominated gain in the apparent free energy.

Diffusion↗

PubMed1978

Kinetic and thermodynamic aspects of in vitro interphase transfer of tetracyclines II: influence of divalent metal salts.

With a two-phase in vitro model composed of an aqueous pH 5.5 buffer and 1-octanol, the kinetics of the interphase transfer of tetracycline derivatives were examined in the presence and absence of calcium and magnesium salts, and the contribution of some functional group substituents to the "apparent" free energy changes for partitioning of tetracyclines was evaluated. Only small changes were observed in kf, kb, K0w, and apparent functional group free energy changes, deltaFG deltaF, in the presence of divalent metals as compared to values observed in the absence of these metals. Introduction of the C-6beta hydroxyl group on the tetracycline nucleus decreased the apparent K0w because of a positive apparent deltaFG deltaF contribution, whereas introduction of C-5 hydroxyl, C-6alpha methyl, or C-7 chloro groups increased the apparent K0w through negative apparent deltaFG deltaF contributions.

Cations, Divalent↗

PubMed1992

Quantitative analyses of hydrophobicity of di- to pentapeptides having un-ionizable side chains with substituent and structural parameters.

With experimental conditions established recently, we measured the partition ratio (P') of 124 di- to pentapeptides composed of amino acids having un-ionizable side chains in a 1-octanol:pH 7.0 aqueous phosphate buffer system as an approximate zwitterionized "molecular" partition coefficient (P). Empirical equations of good quality, correlating the variations in log P' value of peptides with free energy-related physicochemical parameters for the side chain substituents and substructures, were formulated. The significant side chain parameters were those representing the intrinsic hydrophobicity, the steric effect on the relative solvation of functional groups on the backbone, and the conformational potential index derived from the Chou-Fasman beta-turn potential parameters. For polar side chains, specific indicator variables were required for intramolecular hydrogen-bond formations and the "polar proximity effect" for reductions of hydrophilicity observed when polar groups are crowded together. The proline residue was shown to contribute to the log P' value depending not only on its location on the backbone but also on the number of residues in peptides. On the basis of the analyses, we proposed a new "effective" hydrophobicity index for un-ionizable side chains which could predict the secondary structure of oligopeptides.

Algorithms↗

PubMed1975

Rat liver alcohol dehydrogenase isozymes: influence of infection with Trypanosoma.

A study has been made of changes in alcohol dehydrogenase (ADH) isozymes in livers of rats infected with the following trypanosomes: Trypanosoma cruzi, T. rhodesiense, T. congolense, and six geographical isolates of T. lewisi. A control group of the same age was injected with saline, and another left uninjected. Liver homogenates were electrophoresed in noble agar gels followed by formazan staining according to the method of Ursprung and Leone (1965). Of a total of 25 replicates, 15 showed that the level of rat liver ADH isozymes was similar in the uninjected and saline injected animals; 6 replicates showed a slightly higher level of ADH isozymes in uninjected than saline injected control rat livers, and 4 replicates had a higher level in saline injected than in the uninjected. With either 1-octanol or ethanol as substrate, a marked elevation of ADH activity was observed beginning with day 7 post inoculation in rat livers infected with T. cruzi, T. lewisi, and T. congolense, or as early as day 4 post inoculation with T. rhodesiense. The elevation persisted 59 days or more in rat livers infected with T. lewisi, but rats infected with the pathogenic species usually died 5 to 14 days after infection. The elevation of ADH isozymes has also been demonstrated spectrophotometrically for the first 5 minutes of reaction time, using acetaldehyde as substrate. Also observed in livers infected with pathogenic species and certain strains of T. lewisi were: (1) ADH isozyme pattern changes involving an elevated level of certain isozymes only, and (2) abnormal isozyme mobilities.

Alcohol Oxidoreductases↗

PubMedDate not supplied

Response of Nitella internodal cell to chemical stimulation. A model for olfactory receptor system.

Electrical response to excitable internodal cell of Nitella was studied by applying various kinds of odorants to the cell. Changes in membrane potential and resistance during responses induced by odorants were measured intracellularly under a variety of ionic environments in the media. Results were: 1) Some odorants (coumarin, isoamylacetate, methylacetate, 1-octanol, 1-butanol, 1-propanol) produced an all-or-nothing type action potential when the concentration of odorant exceeded a certain threshold. The action potential was followed by a gradual depolarization of the potential whose amplitude depended on the odorant concentration, C. Other odorants (heptanoic acid, beta-ionon) induced gradual depolarization of the membrane potential without evoking an action potential. 2) Membrane resistance Rm changed in various ways during depolarization: some odorants led to a temporal or gradual decrease in Rm, and others caused an increase in Rm when the membrane potential was depolarized by the application of odorants. 3) Magnitude of response to odorants OR was found to be represented by the following equation: OR =(alpha + beta square root I) log (C/Cth) for C greater than or equal to Cth where alpha and beta are constants for a given odorant, I the ionic strength in the medium, and Cth the threshold concentration of the odorant. 4) Plots of olfactory threshold of human and of internodal cell of Nitella gave a straight line having slope unity. 5) Local application of odorants on the internodal cell induced impulses which transmitted from the part treated by odorants to the other portion. Physico-chemical and physiological implications of the results obtained were discussed.

1-Propanol↗

PubMed1977

Binding of alkyl 1-thio-beta-D-galactopyranosides to beta-D-galactosidase from E. coli.

The binding of a series of alkyl 1-thio-beta-D-galactopyranosides to beta-D-galactosidase from E. coli has been investigated. The inhibition constants were compared to the partition coefficients for the transfer of these substrate-analogues from water to 1-octanol. The relationships between the observed binding-constants and the partition coefficients indicate that part of the aglycon group binds to a hydrophobic area that is limited in relation to the length of hydrocarbon chain that can be accomodated. Outside this area, the hydrocarbon chain is only partially desolvated. The main driving-force for binding of the aglycon group is the increase in entropy resulting from the return of water molecules from the more-organized layer around the solute molecule to the bulk-water phase.

Escherichia coli↗

PubMed1992

Gap junctions in myometrial cell cultures: evidence for modulation by cyclic adenosine 3':5'-monophosphate.

Primary cultures of myometrial cells from juvenile rats, continuous cultures maintained by serial passage, and a pSV3neotransfected myometrial cell line were established and utilized for the study of development and modulation of gap junctional intercellular communication (GJIC) in vitro. The smooth muscle origin and homogeneity of the cultures were verified by immunofluorescence staining of alpha-smooth muscle actin and cellular desmin. Although gap junctions were not detected in thin sections of juvenile and adult myometrial tissues by transmission electron microscopy, they were detected in cultured myometrial cells derived from juvenile and adult animals. The presence of GJIC in cultured cells was confirmed using a fluorescence recovery after photo-bleaching assay. Administration of exogenous estradiol-17 beta (10(-7) M) resulted in an increase in GJIC in primary and passage 9 myometrial cultures, whereas pSV3neo-transfected myometrial cells were not significantly different from untreated controls. The lack of estrogen responsiveness in pSV3neo-transfected cultures correlated with lower levels of estrogen receptors than in primary cultures. Addition of 1 mM 8-bromo-cAMP resulted in rapid (within 2 min) increases in dye transfer in both control and estradiol-17 beta-primed primary cultures. Uncoupling of cells by treatment with 1 mM 1-octanol, followed by addition of 1 mM 8-bromo-cAMP, resulted in increased GJIC in control and estradiol-17 beta-primed cultures, although up-regulation of GJIC in estradiol-17 beta-primed cultures was much greater than in control cultures. Comparative experiments carried out on a spontaneously immortalized rat granulosa cell line (SIGC), which expresses the same connexin43 species as myometrial cells, exhibited similar responses to exogenous 8-bromo-cAMP following uncoupling of gap junctions with octanol. While the results of these investigations may not be extrapolated to myometrium in vivo, they suggest that myometrial cell culture may offer additional opportunities to explore the temporal expression and modulation of GJIC in myometrium.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1992

Relationships among antibacterial activity, inhibition of DNA gyrase, and intracellular accumulation of 11 fluoroquinolones.

A series of 11 fluoroquinolone antibacterial agents, including 8 newly synthesized molecules and 3 reference compounds (pefloxacin, ciprofloxacin, and sparfloxacin), were tested for their MICs against Escherichia coli, Staphylococcus aureus, and Pseudomonas aeruginosa. The intracellular accumulation of fluoroquinolones by these microorganisms was measured by centrifugation through silicone oil and a fluorescence assay. The minimal effective dose (MED) was determined for all agents in a supercoiling assay with E. coli DNA gyrase. The hydrophobicities of the quinolones were determined and expressed as the logarithm of the coefficient of distribution (log D) between 1-octanol and phosphate buffer (pH 7.2). No correlation was found between MICs and cell accumulation for the quinolones studied. A correlation was found between log D and accumulation by S. aureus (r = 0.71, n = 11), and an inverse correlation was found between log D and accumulation by E. coli (r = 0.73, n = 11) and P. aeruginosa (r = 0.64, n = 10). The correlation coefficients between MICs and MED for E. coli, which were 0.60, 0.64, and 0.74 (n = 11) for E. coli, P. aeruginosa, and S. aureus, respectively, rose to 0.85, 0.74, and 0.74 (n = 11) for the same microorganisms, respectively, when the accumulation of the drug by the cell was taken into account. It was concluded that the inhibitory activity against DNA gyrase remains the most important parameter for quinolone potency, but that intracellular accumulation must be taken into account, since, for a given organism, both parameters are under the control of the physicochemical properties of the quinolones.

Anti-Infective Agents↗

PubMed1976

Conditional spore cortex-less mutants of Bacillus sphaericus 9602.

Lysine-requiring mutants of Bacillus sphaericus 9602 were isolated and classified into three groups by their mutation site in the pathway of lysine biosynthesis. The Group I mutant lacks meso-alpha, epsilon-diaminopimelic acid (meso-Dap) decarboxylase activity, but Group II and III mutants have a normal level of Dap decarboxylase activity. A Group II mutant makes dipicolinic acid from an intermediate in the lysine pathway, but Group III mutants do not. In the absence of meso-Dap in the culture, muramic lactam content in the spore cortex of Group II and III mutants is very low, compared to the wild type content. Addition of meso-Dap to the culture causes an increase of muramic lactam content. Since meso-Dap is detectable only in the spore cortex of B. sphaericus 9602, almost all of the muramic lactam in the spore is probably also located in the cortex. Group I mutants grown in the presence of L-lysine sporulate normally. Group II and III mutants produce oval and nonrefractile spores under the same conditions but the addition of meso-Dap to the culture results in the production of round and refractile spores. Thus, the presence of cortex in the spore is essential to give the round and refractile spores in B. sphaericus. The presence of cortex is also required for the accumulation of dipicolinic acid in the sporulating cells. Furthermore, 1-octanol resistance of the spore depends only on the presence of cortex but both cortex and dipicolinic acid are required for heat resistance of the spore.

Bacillus↗

PubMed1992

Electrochemical determination of partition coefficients of drugs.

An electrochemical method for the determination of partition coefficients of drugs that can exist as ions in aqueous solutions is presented. The method involves cyclic voltammetry at the polarizable interface between two immiscible electrolyte solutions. Because n-octanol is an unsuitable solvent for electrochemical purposes, 1,2-dichloroethane, which has electronic properties similar to those of n-octanol, was used in the measurements. The values obtained could be correlated with the values for n-octanol-water partition taken from the literature by an approach based on the linear solvation relationship: log P1 = a log P2 + b; in this relationship, a and b are constants and P1 and P2 correspond to the two different organic and aqueous phase partition equilibria. Furthermore, aqueous diffusion coefficients of drugs were determined from voltammograms.

1-Octanol↗

PubMed1992

Modulation of cell-to-cell coupling between myometrial cells of the human uterus during pregnancy.

OBJECTIVE: The purpose of this study was to investigate changes in cell-to-cell coupling of human myometrium during pregnancy to assess the presence and permeability of gap junctions. STUDY DESIGN: To evaluate the coupling, input resistance was measured and intercellular spread of Lucifer yellow was observed with microelectrode techniques in intact myometrial preparations from four nonpregnant women, 13 women not in labor, and three women in labor. Octanol, isoproterenol, and dibutyryl adenosine 3',5'-cyclic monophosphate were applied to the preparations to assess their effects on cell-to-cell coupling. RESULTS: Input resistance of myometrial cells was decreased (p less than 0.001) and intercellular spread of Lucifer yellow was increased during pregnancy. Octanol, isoproterenol, and dibutyryl adenosine 3',5'-cyclic monophosphate rapidly and reversibly increased input resistance (p less than 0.001 for all these agents) and blocked Lucifer yellow spread in tissues from pregnant patients. CONCLUSIONS: Cell-to-cell coupling between human myometrial cells is spontaneously improved during pregnancy because of the presence of gap junctions. The coupling is rapidly and reversibly decreased by octanol, isoproterenol, and dibutyryl adenosine 3',5'-cyclic monophosphate as a result of decreased permeability of gap junctions. These two methods of modulation of gap junctions are suggested to be major mechanisms for control of myometrial contractile activity in the human uterus during pregnancy.

1-Octanol↗