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PubMed1996

[Substance P, somatostatin and monoaminergic transmitters in the cerebrospinal fluid of patients with chronic idiopathic trigeminal neuralgia].

The etiology of trigeminal neuralgia is unknown, but both peripheral and central causes have been suggested. To investigate the role of central neurochemical mechanisms we measured epinephrine, norepinephrine and their breakdown product, vanilly mandelic acid (VMA), in the cerebrospinal fluid (CSF) of 16 patients (53.3 +/- 8.3 years) suffering from trigeminal neuralgia. As markers for the dopaminergic system, we determined CSF levels of dopamine and its metabolite homovanillic acid (HVA). As a marker for the serotonergic system, we measured CSF levels of serotonin metabolite 5-hydroxyindoleacetic acid (5-HIAA). In addition, levels of the neuropeptides substance P and somatostatin were determined. The concentration of norepinephrine (P < 0.01), VMA (P < 0.05) and HVA (P < 0.05) were significantly decreased in patients with trigeminal neuralgia and correlated with the duration of the disease and depression scores. 5-HIAA was also significantly decreased (P < 0.05) compared to control patients. Whereas substance P was significantly elevated (P < 0.05), somatostatin was significantly decreased (P < 0.05). Various correlations between the classical neurotransmitters and the neuropeptides could be established. We hypothesize than the sum of complex neurochemical changes plays a role in the etiology of trigeminal neuralgia, which can be separated in local and more central proceedings. The increase in substance P, a major nociceptive neuromodulator, supports the concept of a local neurogenic inflammation, possibly located in the trigeminovascular system. Depending on the duration of the disease and depression, the loss of serotonergic, dopaminergic and noradrenergic innervation seems to reflect more central changes, possibly due to alterations in their antinociceptive descending pathways.

English Abstract↗
PubMed1984

Transfer and metabolism of norepinephrine studied from maternal-to-fetal and fetal-to-maternal sides in the in vitro perfused human placental lobe.

An in vitro system for the dual perfusion of an isolated lobe of human placenta was used to study transfer and metabolism of 3H-labeled norepinephrine at two different concentrations. At 39 mumol/L, the transfer of total radioactivity from the maternal to the fetal side was 11.60% +/- 0.60% and significantly higher (p less than 0.05) than that in the opposite direction (6.50% +/- 0.37%). In both directions almost 50% of tritium was transferred as norepinephrine while the rest was metabolized and appeared on the other side as normetanephrine, dihydroxymandelic acid, and vanillylmandelic acid. When a reduced concentration (870 nmol/L) was infused into either the maternal or the fetal compartment, transfer and metabolism were similar to those determined before. Analysis of the tissue showed 50% of total radioactivity as normetanephrine, dihydroxymandelic acid, and vanillylmandelic acid and 17% as conjugates. Inclusion of the monoamine oxidase inhibitor clorgyline in the perfusate significantly reduced fetal-to-maternal transfer but not transfer in the reverse direction. In addition, inhibition of placental monoamine oxidase resulted in a considerable reduction in dihydroxymandelic acid and vanillylmandelic acid while the normetanephrine fraction increased. Norepinephrine significantly increased glucose utilization and lactate production. A possible physiologic role of norepinephrine transferred from the fetal into the maternal circulation during labor is discussed.

Antipyrine↗
PubMed1986

Isolation of 2-hydroxycarboxylic acids with a boronate affinity gel.

Boric acid has been known to make a complex with 2-hydroxycarboxylic acids. Based on this principle, we have developed a new method for isolation of vanillylmandelic acid, p-hydroxymandelic acid, vanillyllactic acid, and p-hydroxyphenyllactic acid in urine. The technique involves two steps: extraction of lipophilic compounds from urine with n-butanol and selective isolation of 2-hydroxy acids in the n-butanol phase on a phenylboronate gel column. 2-Hydroxy acids were eluted from the column with 1.5 ml of 2% acetyl chloride in methanol with the recoveries of ca. 70%. According to analysis of urinary extract by gas chromatography--mass spectrometry, the mean excretion rates of the above four compounds in 12 healthy subjects were 3.68, 1.93, 0.091, and 1.08 mg/day, respectively.

Boronic Acids↗
PubMed1994

Metabolism of [3H]-noradrenaline in human dental pulp in vitro.

Slices of pulp from human maxillary and mandibular molar and promolar teeth were incubated with [3H]-noradrenaline (0.2 mumol/l) for 30 min after which the [3H]-noradrenaline and [3H]-metabolites in the tissue and medium were assayed by column chromatography. The deaminated metabolites 3,4-dihydroxy phenyl glycol (DOPEG) and 3,4-dihydroxy mandelic acid (DOMA) constituted 81% of the metabolites formed. Cocaine, an inhibitor of uptake1, decreased the formation of DOPEG and DOMA as well as the accumulation of [3H]-noradrenaline. In contrast to findings in rabbit pulp, when the disposition of exogenous noradrenaline in human pulp was examined by monoamine fluorescence histochemistry there was no evidence of extraneuronal accumulation of noradrenaline by connective tissue cells. In further experiments, pulp that had been incubated in [3H]-noradrenaline (0.6 mumol/l) for 30 min and superfused for 200 min contained [3H]-noradrenaline (183 pmol/g) and [3H]-DOMA (89 pmol/g). The 3H that overflowed into the perfusate between 85 and 90 min consisted mainly of metabolites. Stimulation of the sympathetic nerves through field electrodes increased the overflow of [3H]-noradrenaline into the perfusate threefold without affecting the overflow of metabolites. The increase was much greater (eightfold) in the presence of an alpha-adrenoceptor antagonist (rauwolscine; 0.1 mumol/l), plus inhibitors of uptake1 (desipramine; 0.3 mumol/l) and uptake 2 (corticosterone; 10 mumol/l). The results are interpreted as evidence that in human dental pulp the disposition of exogenous noradrenaline is determined largely by uptake by sympathetic nerves. After uptake, noradrenaline is deaminated by intraneuronal monoamine oxidase to DOPEG and DOMA.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The inhibition of cholesterol esterification by cyclandelate in transformed mouse macrophages.

Cyclandelate (trimethylcyclohexanyl mandelate) inhibited cholesterol esterification in a transformed mouse macrophage cell line (J774) with a concentration of approximately 20 microM being required for half-maximal inhibition. The intact drug was required for its inhibitory action since neither of its hydrolysis products, trimethylcyclohexanol and mandelic acid, caused any inhibition even at high concentrations. The drug entered the cells very rapidly with inhibition being apparent within the shortest time possible to measure esterification (15 min after drug addition). The rate of cholesterol esterification returned to control values when drug-inhibited cells were incubated in drug-free medium indicating a rapid loss of drug from the cells. Loading of cells with cholesterol had no effect on the inhibitory action of cyclandelate, and the inhibition of esterification of cholesterol appeared to be specific, since the syntheses of phospholipid and triacylglycerol (which also involve the action of acyltransferases) were not affected by the drug. Similar inhibitions of cholesterol esterification were seen in four other cell lines, a human osteosarcoma, Chinese hamster ovary cells, a human transformed macrophage cell line (U937) and human umbilical cord vein endothelial cells, as well as in slices of pig aorta, indicating a general action in extra-hepatic tissues where the drug is not hydrolysed.

Animals↗
PubMed1983

Bone marrow cell chromosomal aberrations and styrene biotransformation in mice given styrene on a repeated oral schedule.

Styrene's capacity to induce chromosomal aberrations was studied in bone marrow cells of CD1 male mice. No mutagenic effect could be detected after either a 4-day treatment course with daily oral doses of 500 mg/kg or a 70-day course with daily oral doses of 200 mg/kg. Urinary elimination of styrene metabolites related to styrene-7,8-oxide formation (i.e. phenylethylene glycol, mandelic acid, benzoic acid, phenylglyoxylic acid and total mercapturic acids) was quantitatively evaluated in the group of mice given the 200 mg/kg dose. In parallel, kinetic studies were made on styrene and styrene-7,8-oxide blood concentrations in the same group of animals. These determinations were carried out on days 1 and 70 of treatment by spectrophotometric, gas chromatographic and mass fragmentographic procedures. Not even nanograms of styrene-7,8-oxide were found in the blood of styrene-treated mice. This suggests that the metabolite does not migrate from the cellular compartment where it is formed being immediately metabolized or irreversibly bound to cellular structures. This observation could well explain the lack of mutagenic effects observed.

Administration, Oral↗
PubMed1982

Excretion of biogenic amine metabolites in anorexia nervosa.

Urinary metabolites of catecholamines and indoleamines have been investigated in 16 patients with anorexia nervosa (AN) and 13 controls using a HPLC-method. Vanillic mandelic acid, 3-methoxy-4-hydroxyphenylglycol, homovanillic acid, 3,4-dihydroxyphenylacetic acid, 5-hydroxyindole acetic acid and indoleacetic acid were significantly decreased in the pre-treatment phase. In four patients long-term treatment including parenteral and enteral nutrition together with psychological methods resulted in an increase in the levels of these substances and this correlated with increased weight gain and urinary creatinine. It is concluded that both central and peripheral disturbances are involved in AN, particularly with regard to biogenic amine metabolism.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1987

Cocaine inhibits extraneuronal O-methylation of exogenous norepinephrine in nasal and oral tissues of the rabbit.

Nasal mucosa (respiratory and olfactory) and lingual gingiva of the rabbit were depleted of their sympathetic nerves by superior cervical ganglionectomy. In the innervated nasal mucosa, exogenous tritiated norepinephrine (3H-NE) was metabolised mainly to tritiated 3,4-dihydroxyphenylethylene glycol (3HDOPEG) and 3,4-dihydroxy mandelic acid (3HDOMA), whereas after denervation it was metabolised mainly to tritiated normetanephrine (3HNMN). In the denervated mucosa, cocaine (30 umol/1) inhibited 3HNMN formation by 50-60%. Cocaine also inhibited 3HNMN formation by 60% in the denervated lingual gingiva. It is concluded that the tissues metabolise 3H-NE via a cocaine-sensitive extraneuronal uptake and O-methylating system similar to that which has been shown to be present in dental pulp.

Animals↗
PubMed1987

Chromosome aberrations, micronuclei and sister-chromatid exchanges in blood lymphocytes after occupational exposure to low levels of styrene.

Chromosome aberrations, micronuclei and sister-chromatid exchanges were analysed in blood lymphocytes of 21 reinforced plastic workers, exposed to styrene from 1 to 25 years, and 21 control persons. Occupational hygienic measurements showed personal exposure to styrene to range from 34 to 263 mg/m3 air, the average was 98 mg/m3. Urinary mandelic acid levels of the workers varied from below detection limit to 7 mM/1 l urine. No increase was detected in the frequency of any of the cytogenetic endpoints studied. No correlations between the number of aberrations, micronuclei or SCEs on one hand and the extent or duration of exposure to styrene on the other could be detected.

Adult↗
PubMed1991

Biomarkers in styrene-exposed boatbuilders.

14 fiberglass-reinforced plastics (FRP) boatbuilders were compared with 9 unexposed controls with respect to several chemical specific and nonspecific biomarkers measured in peripheral blood. Biomarkers included styrene-hemoglobin adducts (styrene-Hb), sister-chromatid exchanges (SCEs), micronuclei (MN), single-strand breaks (SSBs) and N-acetoxy-2-acetylaminofluorene-induced DNA binding (NA-AAF binding) as a measure of susceptibility to DNA damage. Workers' exposures averaged 11 ppm (8-h TWA; geometric mean) and ranged from 0.6 to 44 p.p.m. Mandelic acid levels were measured in end-of-shift urine samples and reflected an average styrene exposure equivalent to 15 p.p.m. There was a large though not significant difference in levels of styrene-Hb adducts among exposed workers and controls, largely the consequence of a single heavily-exposed individual with an extremely high level of adducts. Significant differences between biomarker levels in exposed workers and controls were observed with MN, SSBs and NA-AAF binding. No significant differences were seen in mean levels of SCEs nor in the incidence of cells with a high frequency of SCEs. The data suggest that exposure to levels of styrene in occupational settings near or below the current OSHA standard (50 p.p.m.) can induce damage at the cellular/molecular level. Appropriately-selected panels of biomarkers can be useful in identifying potentially harmful exposures.

Acetoxyacetylaminofluorene↗
PubMed1990

Effects of shosaikoto, an oriental herbal medicinal mixture, on age-induced amnesia in rats.

The possibility of naturally occurring amnesia was examined in aging Fischer F254 rats. Animals 110 weeks old showed a loss of learning and memory in a passive avoidance responses (PAR) failure test. When 120 mg/kg/day of Shosaikoto extract was placed in the diet after 72 weeks of age to 110 weeks, it improved age-induced PAR failure in both the two-compartment avoidance box test and the step-down test. The responses of 110-week-old Shosaikoto-treated rats on both PAR failures were almost the same as those of non-treated 6-week-old rats. In these Shosaikoto-treated rats, dopamine was increased and norepinephrine and vanillyl mandelic acid were decreased in brain relative to those in non-treated aging rats.

Administration, Oral↗
PubMed2004

Capillary electrophoresis in the determination of anionic catecholamine metabolites from patients' urine.

A micellar electrokinetic capillary chromatographic method for determining anionic catecholamine metabolites from patient urine samples was established. The optimum electrolyte solution (pH 10.6) was made of tetraborate and sodium dodecyl sulphate into water. Furthermore, studies were focused to optimize solid-phase extraction clean-up steps to concentrate patient urine samples for identification of catecholamines with UV detection. The water-micelle distribution coefficients (octanol-water partition coefficient, log Pow) for the analytes were determined by conductometric titration. High plate numbers (120,000-200,000/40 cm detection window) and small diffusion coefficients (2.00-3.50 x 10(-6) cm(-2) s(-1)) resulted in high resolution and symmetry of the analyte zones. The standard deviations of the migration times and the peak heights were less than 3 and 7%, respectively. The octanol-water coefficients increased in the order of decreased pKa1 value of the analytes, why separation between structurally related vanillinic mandelic acids could be obtained. Limits of detection and quantification were around 0.05 and 0.1 microg/ml, respectively, except for dopamine. The concentrations of the catecholamine metabolites in the studied patient urines varied from 0.186 to 76.4 microg/ml. The results showed evidences of serious diseases among the patients.

Anions↗
PubMed2005

Shortcut method for evaluation and design of a hybrid process for enantioseparations.

Hybrid processes for enantioseparations have a considerable potential for reducing investment and operational costs. An example is the combination of simulated moving bed (SMB) chromatography and selective crystallisation. However, the design of integrated processes is a difficult task. A shortcut method is presented that can serve as a tool for design and estimation of the potential of such processes. The approach requires only limited experimental data and thus allows for systematic parameter studies. The method is based on the determination of the purity-performance characteristic of the SMB process and rigorous application of mass balances. The use of relative mass fluxes allows derivation of simple algebraic expressions for essential process parameters. The significant potential of combining SMB and crystallisation is demonstrated for the example of the separation of mandelic acid enantiomers.

Chromatography↗
PubMed2006

Comparison of helical twisting powers of novel fluorinated amphiphilic enantiomers with their hydrogenated counterparts.

This is the first report on novel amphiphilic enantiomers as esters of alanine and serine with a partially fluorinated octyl chain (L-APFOE and L-SPFOE), which form intrinsic chiral nematic (N*) phases with water only and exhibit very high helical twisting powers (htps) compared to their hydrogenated counterparts, dodecylesters of L-alanine (L-ADDE) and L-serine (l-SDDE). They also exhibit a wider N* range than those known in the literature. Furthermore, the htps of the chiral dopants mandelic acid (MA) and hexahydromandelic acid (HHMA) in the racemic nematic phase of DL-SPFOE and DL-APFOE are remarkably higher than those in the hydrogenated counterparts. The tremendous increase in chirality (htps) of the same single chiral center is a new phenomenon in micellar N* phases and is attributed to a "pivot" effect of the fluoroalkyl chain. As a result, a "skewed micelle" model is proposed to explain why the htp value of L-APFOE is higher than that of L-SPFOE, and accordingly how the intermicellar chirality transfer (chiral induction) may be visualized. The simplicity of these binary mixtures and the enlargement in htp of the single chiral centers visualized as the "skewed micelle" model may provide a basis vital for future computer modeling of chiral lyotropics.

Letter↗
PubMed2001

Fitting adsorption isotherms to the distribution data determined using packed micro-columns for high-performance liquid chromatography.

Knowing the adsorption isotherms of the components of a mixture on the chromatographic system used to separate them is necessary for a better understanding of the separation process and for the optimization of the production rate and costs in preparative high-performance liquid chromatography (HPLC). Currently, adsorption isotherms are usually measured by frontal analysis, using conventional analytical columns. Unfortunately, this approach requires relatively large quantities of pure compounds, and hence is expensive, especially in the case of pure enantiomers. In this work, we investigated the possible use of packed micro-bore and capillary HPLC columns for the determination of adsorption isotherms of benzophenone, o-cresol and phenol in reversed-phase systems and of the enantiomers of mandelic acid on a Teicoplanin chiral stationary phase. We found a reasonable agreement between the isotherm coefficients of the model compounds determined on micro-columns and on conventional analytical columns packed with the same material. Both frontal analysis and perturbation techniques could be used for this determination. The consumption of pure compounds needed to determine the isotherms decreases proportionally to the second power of the decrease in the column inner diameter, i.e. 10 times for a micro-bore column (1 mm I.D.) and 100 times for capillary columns (0.32 mm I.D.) with respect to 3.3 mm I.D. conventional columns.

Adsorption↗
PubMed2002

Impact of adsorption isotherm parameters on the performance of enantioseparation using simulated moving bed chromatography.

Often there are several chromatographic systems, i.e., combinations of mobile and stationary phases, available to solve a certain separation problem. Essential differences of these chromatographic systems are the separation factors and the efficiencies. For preparative applications in addition also the column saturation capacities and solubility limits are of importance. The impact of all these parameters appears to be rather well understood for conventional overloaded elution chromatography using a single column. In the last years the continuous simulated moving bed (SMB) process was increasingly used as a powerful alternative to batch elution since increased productivities and reduced solvent consumptions could be realised. However, the selection of suitable chromatographic systems is more sophisticated for this process. In this paper five different chromatographic systems capable of separating the enantiomers of mandelic acid are compared based on the achievable productivities using SMB chromatography. For these five systems the adsorption isotherms have been determined experimentally. Subsequently, an analysis of the SMB process was performed numerically using a well-established model.

Adsorption↗
PubMed1978

Treatment of idiopathic orthostatic hypotension (Shy-Drager syndrome) with indomethacin.

Four patients with idiopathic orthostatic hypotension (I.O.H.) and one with postural hypotension and diabetes were studied. Plasma-renin activity (P.R.A.) was low and did not rise appropriately with salt restriction and diuretic stimulation. Aldosterone levels were normal and rose with diuretic therapy. Plasma-volume, plasma dopamine beta-hydroxylase, urinary catecholamines, metanephrines, and vanillyl mandelic acid (V.M.A) were normal. Treatment with indomethacin (75-150 mg/day) raised the upright blood-pressure (B.P.) by an average of 20-30 mm Hg diastolic and allowed the four patients with I.O.H. to walk about without orthostatic symptoms but it had no effect in the fifth patient. When indomethacin was discontinued in one patient who had been taking it for 9 months with symptomatic relief, the B.P. fell to pretreatment levels within 48 h. When indomethacin was reinstituted the B.P. rose again. Indomethacin was more effective in these patients than either propranolol or fludrocortisone. There may be an absolute or relative excess of certain vasodepressor prostaglandins in the peripheral vessels which results in pooling of blood and orthostatic hypotension. If this is the case indomethacin might improve the orthostatic symptoms of I.O.H. by its inhibitory effect on prostaglandin synthesis, but its mechanism of action remains to be determined.

Administration, Oral↗