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At least 163 records · Page 9Linked to original sources
PubMed1993

Conformations of large cycloalkanes: cyclooctadecane, cyclononadecane and cycloicosane.

The conformations of cyclooctadecane, cyclononadecane, and cycloicosane were generated by a stochastic program that works in conjunction with MM2. The shapes of the rings are analyzed in terms of previous work by Dale and others, and in terms of distributions of energies, torsion angle distributions, and torsion angle sequences. A new shape element called the 'nick' has been discovered, and it seems to be increasingly important with 18-membered and larger rings. Previously suggested relationships between ring size and energy distribution were observed, and a geometrical explanation is provided for the relative distributions of stable conformations in 16-, 18-, and 20-membered rings.

Algorithms↗
PubMed1986

Pharmacokinetics of dezocine, a new analgesic: effect of dose and route of administration.

The pharmacokinetics of intravenous (IV) dezocine, and bioavailability of intramuscular (IM) and subcutaneous (SQ) dezocine, were evaluated in healthy male volunteers. Elimination half-life following 5, 10, and 20 mg IV doses averaged 2.6-2.8 h, and was independent of dose. Clearance decreased slightly, although significantly, with dose. After Deltoid IM injection, dezocine was rapidly absorbed (peak level: 0.6 h after dose), with bioavailability 97%. Thus dezocine has extensive distribution, high clearance and short half-life over a range of IV doses. It is rapidly and completely absorbed following IM or SQ administration.

Adolescent↗
PubMed1994

Large scale production and semi-purification of kedarcidin in a 1000-L fermentor.

Actinomycete strain ATCC 53650 was grown in a 1000-L fermentor containing 680 L of medium and the production of kedarcidin was monitored by HPLC. The titers of kedarcidin in the fermentor cultures were 0.49-0.53 mg ml-1. A quick and efficient purification method involving the use of anion exchange resin DE23 (batch adsorption-desorption) and an ultrafiltration system yielded high recovery (65% yield) of kedarcidin from the fermentor culture. Over 200 grams of lyophilized kedarcidin of 70% purity was recovered from each of two 1000-L fermentor cultures using this process.

Actinomycetaceae↗
PubMed2004

Solid-phase extraction of L-muscone from aqueous samples with Amberlite XAD-4 for gas chromatographic assay.

An efficient analytical method was devised for the accurate L-muscone assay in aqueous samples. It involves solid-phase extraction of L-muscone in adsorption mode using XAD-4 as the sorbent and dichloromethane modified with 10% (v/v) methanol as the eluting solvent. The gas chromatographic analysis of the eluate residue dissolved in toluene on a DB-5MS capillary column provided complete resolution of L-muscone from the co-extracted interferences. The overall method showed excellent linearity (r2 > or = 0.9994) in the range of 0.1 to 2.0 microg/mL with good intra- and inter-day precisions (% RSD = 2.5 to approximately 7.3) and with high extraction recovery rates (> or = 98.1%). When the present method was applied to a L-muscone herbal drink product, the within-batch RE (%) in the labeled concentration (1.5 microg/mL) for the three randomly chosen bottles were -2.4, -1.3 and -3.3 with high precision (% RSD < or = 3.1). The present method is considered to be suitable for quality control evaluation on liquid drinks and other complex formulations fortified with L-muscone.

Chromatography, Gas↗
PubMed1985

Double-blind placebo-controlled comparison of dezocine and morphine for post-operative pain relief.

Dezocine, a new mixed agonist-antagonist-type opioid analgesic, was compared in a double-blind trial with placebo and 10 mg of morphine in 190 patients with acute postoperative pain. The medications were given intramuscularly. Dezocine was administered at three dose levels (5, 10, and 15 mg). Pain relief scores, sedation, and side effects were recorded at 15, 30, 60, 120 and 240 min after injection. Significantly higher pain relief scores (p less than 0.05) were reported for the groups receiving dezocine 10 and 15 mg than the placebo group at all observation times, except for dezocine 15 mg at four hours. Morphine produced significantly better pain relief than placebo only between the second and fourth hour after administration. Significantly better pain relief was obtained with dezocine (10 and 15 mg) than with morphine during the first hour. The mean four-hour cumulative pain relief scores (TOTPAR) were significantly (p less than 0.05) higher than placebo for all active treatment groups. Side effects were few with no significant differences between the treatment groups. Seventy-nine per cent of the patients in the dezocine 15 mg group, and 73, 68, 58 and 50 per cent respectively, of the patients in the dezocine 10 mg, dezocine 5 mg, morphine 10 mg and placebo group had a satisfactory clinical response. Significantly (p less than 0.05) more patients in the groups receiving dezocine 10 and 15 mg than in the placebo group had a satisfactory clinical response; the difference was not significant for the dezocine 5 mg and morphine 10 mg groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesics, Opioid↗
PubMed2000

Sex-related differences in the antinociceptive effects of opioids: importance of rat genotype, nociceptive stimulus intensity, and efficacy at the mu opioid receptor.

RATIONALE: Recent studies indicate that morphine is more potent as an antinociceptive agent in male than female rodents and monkeys. OBJECTIVES: To evaluate the influence of sex, nociceptive stimulus intensity and an opioid's relative efficacy on opioid-induced antinociception in rat strains (F344 and Lewis) that display differential sensitivity to morphine antinociception. METHODS: Antinociceptive testing was conducted using a rat warm-water (50-56 degrees C) tail-withdrawal procedure. Dose-response and time-course determinations were performed with various opioids. RESULTS: Across the nociceptive stimulus intensities tested, the high-efficacy mu opioids morphine, etorphine, and levorphanol were equally effective in males and females, but on average 2.5-fold more potent in males. At moderate stimulus intensities, the low-efficacy mu opioid buprenorphine was approximately 0.4-fold more potent in males, and at higher stimulus intensities more potent and effective (greater maximal effect) in males. At low stimulus intensities, the low-efficacy mu opioid dezocine and the mu/kappa opioid butorphanol were greater than 8.9-fold more potent in males, and at moderate stimulus intensities were more potent and effective in males. At a low stimulus intensity, the mu/kappa opioid nalbuphine was more potent and effective in males. At stimulus intensities in which buprenorphine, dezocine, butorphanol, and nalbuphine produced maximal effects in males but not females, these opioids antagonized the effects of morphine in females. Genotype-related differences were noted as opioids were generally more potent in F344 than Lewis males, whereas no consistent differences were observed between F344 and Lewis females. CONCLUSIONS: That sex differences in the potency and effectiveness of opioids increased with decreases in the opioid's relative efficacy and with increases in the nociceptive stimulus intensity suggests that the relative efficacy of mu opioids as antinociceptive agents is greater in male than female rats.

Analgesics, Opioid↗
PubMed1999

Selective attenuation of the antinociceptive effects of mu opioids by the putative dopamine D3 agonist 7-OH-DPAT.

RATIONALE: The purpose of the present investigation was to evaluate the effects of the D3 agonist (+/-)-7-hydroxy-dipropylaminotetralin (7-OH-DPAT), various dopamine (DA) agonists and DA antagonists on the antinociceptive effects of mu opioids. METHODS: Antinociception was assessed using a warm-water tail-withdrawal procedure in rats. RESULTS: The mu opioids morphine (0.3-10 mg/kg) and dezocine (0.03-3.0 mg/kg) produced dose-dependent increases in antinociception with maximal effects obtained at the higher doses tested. Pretreatment with the putative D3 agonist 7-OH-DPAT (1.0-10 mg/kg) produced a dose-dependent attenuation of the antinociceptive effects of morphine and dezocine. At the highest dose of 7-OH-DPAT tested, the morphine dose-effect curve was shifted rightward by approximately 1.5 log units and the dezocine curve by greater than 2.3 log units. The (+)-isomer of 7-OH-DPAT (1.0 and 3.0 mg/kg) also shifted the morphine dose-effect curve to the right in a dose-dependent manner. The DA D3/D2 agonist (-)-quinpirole (0.1-10mg/kg) attenuated the effects of morphine, but these effects were small in magnitude, not dose-dependent and observed only under a limited set of conditions. The DA D2/D3 antagonist spiperone failed to alter the morphine dose-effect curve, but reversed the effects of 7-OH-DPAT on morphine antinociception. Pretreatment with the DA D1 agonist (+/-)-SKF38393 (1.0 and 10 mg/kg) and the D1 antagonist (+)-SCH23390 (0.1 and 1.0 mg/kg) failed to alter the morphine dose-effect curve. CONCLUSION: The finding that 7-OH-DPAT markedly attenuated the effects of morphine and that these effects were reversed with spiperone suggests that activity at the D3, and possibly the D2, receptor can modulate mu agonist-induced antinociception.

2,3,4,5-Tetrahydro-7,8-dihydroxy-1-phenyl-1H-3-ben↗
PubMed2002

Estrogenic activity of musk fragrances detected by the E-screen assay using human mcf-7 cells.

The widespread use of synthetic musk fragrances and the resultant presence of these substances and their metabolites in the aquatic environment (as well as their accumulation in human adipose tissue) raises the question of whether musk fragrances display endocrine and in particular estrogenic activity. A variety of musk fragrances were tested using the E-screen assay. A statistically significant increase in proliferation rate of human MCF-7 breast cancer cells was detected for two nitro musks (musk xylene, musk ketone), a major metabolite of musk xylene ( p-amino-musk xylene), and the polycyclic musk fragrance AHTN. This indicates that these substances do, in fact, demonstrate estrogenic activity. Coincubation with the antiestrogen tamoxifen showed that the increase in proliferation rate by the musk fragrances is estrogen receptor-mediated. It must be noted, however, that the effective estrogenic strength and estrogenic potency were low compared to 17 b-estradiol. The naturally occurring fragrance muscone from the group of macrocyclic musk fragrances, a group of substances that have not yet been well characterized in respect to their toxicological properties, has also been shown to be weakly estrogenically active in vitro. E-screen analysis showed that the nitro musk metabolites o-amino musk xylene and 2-amino-MK, the macrocyclic musk fragrances ethylene brassylate, ethylene dodecandioate, and cyclopentadecanolide, are not estrogenically active.

Biological Assay↗