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At least 19 recordsLinked to original sources
PubMed1976

Behavioral effects and binding affinities of two stereoisomeric psychotomimetic glycolates.

A comparison was made of the behavioral effects in cats of the dextro and levo isomers of 3-quinuclidinyl benzilate (QB), using a special computer-controlled program. Such psychophysical parameters as rate of response and tendency to use the left or right paw for lever pressing were used primarily to evaluate drug efficacy. The drug did not alter auditory threshold or the percentage of errors in lever pressing. The l-isomer was found to be at least 100 times as potent as the d-isomer, the effects of both being qualitatively similar. After a single dose of 5 mug/Kg of 1-QB, the cats' performance did not return to normal until 5-7 days later. Pretreatment of the cats with a dose of 2 mg/Kg of atropine, an antimuscarinic agent, did not prevent the behavioral effects of 1-QB. The binding affinity of two isomers for synaptic membranes and phosphatidyl serine was identical.

Animals↗
PubMed1979

Phase transition characteristics of diphosphatidyl-glycerol (cardiolipin) and stereoisomeric phosphatidyldiacylglycerol bilayers. Mono- and divalent metal ion effects.

Synthesis and phase transition chaaracteristics of aqueous dispersions of the homologous (12 : 0, 14 : 0, 16 : 0) diphosphatidylglycerols (cardiolipins) and phosphatidyldiacylglycerols are reported. Electron microscopy of the negatively stained aqueous dispersions reveals a characteristic lamellar structure suggesting that these phospholipid molecules are organized as bilayers in the aqueous dispersions. The phase transition temperature (Tm) and the enthalpy of transition (delta H) increase monotonically with chain length in the cardiolipin and phosphatidyldiacylglycerol series; Tm for phosphatidyldiacylglycerol is higher than that for cardiolipin of the same chain-length. The transition temperatures for the enantiomeric sn-3,3- and sn-1,1-phosphatidyldiacylglycerol and for the diastereomeric, meso-sn-1,3-phosphatidyldiacylglycerol are approximately the same. The molar enthalpy for the transition of cardiolipin-NH+4 bilayers is approximately twice the value for the phosphatidylcholines of the same chain length, i.e., the molar enthalpy per acyl chain is approximately the same in the two systems. The transition temperatures for metal ion salts of C16-cardiolipin exhibit a biphasic dependence upon the unhydrated ionic radii, i.e., the highest Tm is observed for Ca2+-cardiolipin and decreases for the salts of ions with smaller and larger ionic radii than that of Ca2+. The lowest Tm is observed for Rb+-cardiolipin. Monovalent metal salts of cardiolipin exhibit two phase transitions. This effect may result from different conformational packing of the four acyl chains due to differences in metal-phosphate binding.

Cardiolipins↗
PubMed1975

Stereoisomeric relationships among anti-inflammatory activity, inhibition of platelet aggregation, and inhibition of prostaglandin synthetase.

This study compares the affects of a new non-steroidal anti-inflammatory drug, d,l-6-chloro-alpha-methyl-carbazole-2-acetic acid, its enantiomers, and indomethacin on platelet aggregation, prostaglandin synthetase, adjuvant arthritis, gastric ulceration and arachidonic acid induced diarrhea. In the adjuvant arthritic rat, doses producing anti-inflammatory activity were similar for all compounds with the exception of the l-isomer which was much less active. On the other hand, indomethacin was 10 to 25 times more potent with regard to inhibition of platelet aggregation, inhibition on prostaglandin synthetase, inhibition of arachidonic acid induced diarrhea, and induction of gastric ulceration than the racemate and its isomers. Such divergence of potencies suggests that the racemate, unlike indomethacin, would have no affect on platelet aggregation and, hence, produce no prolongation of bleeding time at doses possessing anti-inflammatory activity. The data also suggest that the racemate and d-isomer have greater specificity toward anti-arthritic acitvity and are less ulcerogenic than indomethacin. The d-isomer apparently is the more active component of the racemate in all the systems tested since: (a) the d-isomer has 2 to 3 times the inhibitory potency of the racemate and (b) the l-isomer, at high dosages or high concentrations had considerable less affect. Comparison of potencies relative to inhibition of platelet aggregation and of prostaglandin synthetase, are quite close; therefore, mechanistically, the anti-aggregatory affects of these drugs, or lack thereof, may be related to inhibition of prostaglandin synthetase.

Acetates↗
PubMed1978

Mutagenicity to mammalian cells in culture by (+) and (-) trans-7,8-dihydroxy-7,8-dihydrobenzo(a)pyrenes and the hydrolysis and reduction products of two stereoisomeric benzo(a)pyrene 7,8-diol-9,10-epoxides.

The mutagenicity for mammalian cells of benzo(a)pyrene (BP) and 9 of its derivatives was tested by resistance to ouabain in Chinese hamster V78 cells. The derivatives included the (-) and (+) enantiomers of trans-7,8-diol; the racemic (+/-)trans-7,8-diol; two triols, (7/8,9)-triol and (7,9/8)-triol; and four tetrols, (7,10/8,9)-tetrol, (7/8,9,10)-tetrol, (7,9/8,10-triol and (7,9,10/8)-tetrol. Since V78 cells do not metabolize polycyclic hydrocarbons, mutagenesis was tested both in the presence and in the absence of Golden hamster cells capable of metabolizing polycyclic hydrocarbons. Neither BP nor any of its 9 tested derivatives showed mutagenicity for V78 cells in the absence of normal Golden hamster cells. However, in the presence of these cells, BP and the optically active and racemic trans-7,8-diols exhibited a mutagenic response that was dose-dependent. All other derivatives were inactive. The most active mutagenic hydrocarbon was (-) trans-7,8-diol, and activity decreased in the order (+/-)trans-7,8-diol, (+) trans-7,8-diol and BP.

Benzopyrenes↗
PubMed1978

Morphine as a discriminative cue in gerbils: drug generalization and antagonism.

Gerbils were trained in an electrified, T-shaped maze to discriminate between one of the three training doses of morphine (8, 16, or 32 mg/kg) and the nondrug condition. The rate of acquisition of the morphine discriminations was a function of dose, the high dose being the most rapidly discriminable condition. Dose generalization tests with morphine showed that the higher the training dose, the higher the ED50 value in producing 50% morphine-appropriate responding. Antagonism of the discriminable effects of morphine by naltrexone (dose range tested: 0.025-0.40 mg/kg) also was related to the training dose of morphine; i.e., the higher the training dose of morphine, the higher the corresponding ED50 value for blockade by naltrexone. A stereoisomeric requirement for morphine discrimination was evident since levorphanol, but not the analgesically inactive dextrophan, yielded morphine-appropriate responses when tested by substitution.

Animals↗
PubMed1979

Determination of the configuration of epimeric diols of vitamin D3 series by mass spectrometry.

The mass spectral elimination of water in epimeric 1,3-diols of vitamin D3 (colecalciferol) series has been investigated. It was found that the mass spectra of these steroisomers differ sharply in the relative intensities of the ions M-H2O (m/e 382) and a-H2O (m/e +/- 34), where ion a (formed via formal cleavage of the 7, 8-double bond) is characteristic of vitamin D3 and its derivatives. So while epimeric 1, 3-diols of vitamin D3 series have very close UV and NMR characteristics, the comparison of the ratios of the peaks M-H2O and M.+, a-H2O and a, respectively, makes it possible to distinguish between stereoisomeric 1 alpha, 3 beta-, 1 beta, 3 beta-, 1 alpha, 3 alpha- and 1 beta, 3 alpha-diols using their mass spectra.

Dihydroxycholecalciferols↗
PubMed1977

Total synthesis of hexuronic acids.

Six stereoisomeric hexuronic acids (tert-butyl esters of methyl pyranosides) having the altro, manno, gluco, gulo, galacto, and talo configurations were obtained from cis,trans-tert-butyl 2-methoxy-5,6-dihydro-2H-pyran-6-carboxylate (5). The synthesis involved the following successive steps: epoxidation of the double bond in 5, opening of the epoxides with dimethylamine, Cope degradation of the dimethyl-amino derivatives, and hydroxylation of the double bond in the tert-butyl hex-3-enuronates. All compounds were obtained as pure diastereoisomers in racemic form.

Hexuronic Acids↗
PubMed1979

L-glucosylceramide: synthesis, properties, and resistance to catabolism by glucocerebrosidase in vitro.

Procedures for the synthesis and radioactive labeling of L-glucosylceramide are described. This compound is a stereoisomeric analogue of D-glucosylceramide which occurs in nature and accumulates in pathological quantity in the organs and tissues of patients with Gaucher disease. The properties of L-glucosylceramide that have been examined so far have been found to be indistinguishable from those of the naturally occurring glycolipid. However, L-glucosylceramide is completely refractory to enzymatic hydrolysis by purified placental glucocerebrosidase and enzyme(s) present in whole tissue extracts. It is anticipated that L-glucosylceramide will be a uniquely useful substance for exploring pathogenetic processes in animal analogues of Gaucher disease.

Animals↗
PubMed1977

Benzo[a]pyrene diol epoxides: mechanism of enzymatic formation and optically active intermediates.

Studies of the mechanism of benzo[a]pyrene metabolism to reactive diol epoxides and of their disposition indicate that the metabolic intermediates of the activation pathways, 7,8-epoxide and trans-7,8-diol, as well as the two stereoisomeric diol epoxides are all optically active. Benzo[a]pyrene is converted to optically active 9,10-epoxides of (-)trans-7,8-diol by three enzymatic steps: (i) stereospecific oxygenation at the 7,8 double bond of benzo[a]pyrene by the mixed-function oxidases to essentially a single enantiomer of 7,8-epoxide, (ii) hydration of the 7,8-epoxide by epoxide hydratase to an optically pure (-)trans-7,8-diol, and (iii) stereoselective oxygenation by the mixed-function oxidases at the 9,10 double bond of the (-) trans-7,8-diol to optically active r-7,t-8-dihydroxy-t-9,10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene and optically active r-7,t-8-dihydroxy-c-9,10-oxy-7,8,9,10-tetrahydrobenzo[a]pyrene in a ratio of approximately 10 to 1.

Animals↗
PubMed1979

Effect of alanine-containing dipeptides on germination of Bacillus thiaminolyticus spores.

Stereoisomeric alanylalanine (Ala-Ala) derivatives were examined for their effects on germination of Bacillus thiaminolyticus spores. L-Ala-L-Ala and L-Ala-glycine were effective in inducing germination, and their activities were completely inhibited by D-Ala. L-Ala-D-Ala and glycine-D-Ala competitively prevented L-Ala-induced germination. Sarcosine- or beta-Ala-containing L-alanyldipeptides and eight kinds of alanyltripeptides did not show any detectable effect on germinability or any inhibitory effect. No detectable amounts of Ala were found in germination exudates when alanylpeptides were incubated with spores. The ability of these peptides to induce or inhibit germination depends on their steric conformation and a certain distance between the primary amino group and the free carboxyl groups. Involvement of L-Ala dehydrogenase in the initiation of germination is unlikely because L-Ala-L-Ala was not a substrate and L-Ala-D-Ala was not an effective inhibitor of enzyme activity.

Alanine↗
PubMed1975

Adsorption of syndiotactic and isotactic poly(2-vinylpyridine 1-oxide) on quartz surface.

Poly(2-vinylpyridine 1-oxide) inhibits the cytotoxic effects of quartz in cell cultures but the syndiotactic polymer behaves differently from the isotactic and atactic polymers. In each case approximately 1-0 mg/m2 of the polymer represents the adsorption maximum. No difference has been found between the adsorption isotherms of the stereoisomeric polymers or the stability of the adsorbed layers. The layers are not removed by repeated washing. The observations do not support the theory that the poly(2-vinylpyridine 1-oxide) is active because it coats the quartz surface.

Adsorption↗
PubMed1979

Proton magnetic resonance identification and discrimination of stereoisomers of C27 steroids using lanthanide shift reagents.

A simple proton magnetic resonance spectroscopic method is described for the identification and and confirmation of several stereoisomeric paris of C27 stanols as well as their keto and acetate derivatives related to cholesterol. The method, which involves the use of lanthanide shift reagents, is useful in distinguishing clearly between the isomeric pairs differing only in the geometry of a functional group and/or of the A/B-ring junction in the steroid skeleton.

Cholestanes↗