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At least 1,459 records · Page 81Linked to original sources
PubMed1982

Structure of O-glycosidically linked sugar units from plasma membranes of an ascites hepatoma, AH 66.

The structures of O-glycosidically linked oligosaccharides from plasma membranes of AH 66 ascites hepatoma cells have been determined. Glycopeptides were prepared from a Triton X-100 extract of the cells by pronase digestion. From the digest, the glycopeptide containing O-glycosidically linked oligosaccharides was isolated by gel filtration and electrophoresis on a cellulose acetate block. The oligosaccharide chains were isolated as reduced oligosaccharides by treating the glycopeptide with alkaline borohydride. Neutral and acidic oligosaccharides were separated on a column of Dowex 1, and then each of them was further fractionated by gel filtration on Sephadex G-25 (superfine), high voltage paper electrophoresis, and paper chromatography. One reduced monosaccharide, three neutral, and five acidic reduced oligosaccharides were isolated. On the basis of carbohydrate compositions, mass spectra of permethylated oligosaccharides, methylation analysis, and exoglycosidase digestion, their structures were deduced to be as follows: (formula, see text).

Animals↗
PubMed1982

[The effect of beta-receptor blockers and cardiac glycosides on the heart rate, systolic blood pressure and ST interval in submaximal ergometer exertion].

14 males at the age of 49 +/- 6.4 years with condition after myocardial infarction were loaded on the bicycle ergometer according to the criteria of the WHO. After injection of a beta-receptor blocker at the submaximal functional level the product of the pressure frequency decreased by 25% and the watt-pulse increased by 17%. The oxygen pulse and the respiratory quotient remained constant. An additional injection of glycosides did not significantly change these parameters. At the same time no falsely positive evidence concerning the behaviour of the ST-distance as criterium of withdrawal was provoked. The results of the submaximal and symptom-limited function were not falsified in the therapy with beta-receptor-blockers and glycosides, when the criteria of withdrawal recommended by the WHO are used unchangedly.

Adult↗
PubMed1980

Treatment of non-insulin dependent diabetic adults with a new glycoside hydrolase inhibitor (Bay g 5421).

The hypoglycemic effect of a glycoside hydrolase inhibitor (BAY g 5421) was tested in 10 non-insulin dependent, overweight diabetics by means of continuous in vivo glucograms. There was a highly significant reduction of serum glucose with a dosage of 3 x 100 mg glycoside hydrolase inhibitor, after dosage division to 6 x 50 mg there was an additional reduction of blood glucose. This difference, however, could not be determined statistically. Insulin, glucagon and lactate as well as the triglyceride concentration remained unchanged. There were no significant side-effects. Two of the 10 patients complained of meteorism, after specific questioning three more patients offered similar complaints. Discontinuation of the preparation was not necessary.

Acarbose↗
PubMed1980

Hypotensive effects of cardiac glycosides in spontaneously hypertensive rats.

The effects of cardiac glycosides on systolic arterial pressure (SAP) and heart rate (HR) were studied in spontaneously hypertensive (SH) and normotensive (NT) Wistar rats. Ouabain (2 mg/kg), given by i.p. injection to unanesthetized rats, produced a significant decrease in SAP in both SH and NT rats with little concomitant HR change. Baroreceptor denervation abolished the response. To analyze the effects more completely, experiments were done on acutely anesthetized rats. Ouabain was administered i.p. 30 min after induction of anesthesia with alpha-chloralose (60 mg/kg i.p.). alpha-Chloralose alone produced a significant SAP decrease in both SH and NT rats and bradycardia in SH but no significant HR change in NT rats. Ouabain i.p. further reduced SAP in SH but had no effect on NT rats. When given by i.a. bolus injection (250 microgram in 0.1 mg of heparin-saline) to anesthetized (pentobarbital, 40 mg/kg i.p.) rats with intact left carotid sinus nerves, ouabain produced a transient but significant reduction in SAP of SH but NT rats or SH rats with sinoaortic denervation. Digitoxin, given by stomach tube (4--5 mg/kg) for 1 week, decreased SAP in SH but not NT rats. Digitoxin produced significant SAP increases in SH rats with sinoaortic denervation. Arterial baroreceptor discharge is increased by cardiac glycosides. The present results suggest that the reflex hypotensive effects of digitalis drugs are due, at least in part, to sensitization of baroreceptors and that SH rats may be more sensitive to these drugs possibly because of altered intrinsic baroreceptor properties.

Animals↗
PubMed1981

Effects of quinidine on the cardiac-glycoside sensitivity of guinea-pig and rat heart.

Quinidine causes a marked increase in plasma digoxin concentration in patients receiving the glycoside. Whether the sensitivity of the heart to digoxin is altered by quinidine was examined with rats and guinea pigs. In electrically stimulated rat atrial preparations, quinidine failed to affect digoxin-induced inhibition of ouabain-sensitive 42K+ uptake, an estimate of sodium pump activity. Effects of quinidine on digoxin binding to Na+, K+-adenosine triphosphatase (ATPase) in intact cells were examined by perfusion guinea-pig Langendorff preparations with digoxin and estimating the occupancy of the glycoside-binding sites on the enzyme from a reduction in the initial velocity of the ATP-dependent [3H]ouabain binding reaction. Quinidine did not alter the initial velocity of [3H]ouabain binding to ventricular homogenates obtained from digoxin-perfused preparations, indicating that digoxin binding to Na+, K+-AtPase during the perfusion was not altered. In isolated rat heart preparations, quinidine failed to affect the positive inotropic action of ouabain. Nor did quinidine modify the inotropic action of digoxin in Langendorff preparations of guinea-pig heart. Concurrent i.v. infusion of quinidine in anesthetized guinea pigs increased the digoxin concentration in plasma. Thus, quinidine does not modify digoxin-Na+, K+-ATPase interactions or the digoxin-sensitivity of the myocardium. Quinidine-induced alterations in apparent volume of digoxin distribution should quantitatively change the response of the animal to digoxin.

Animals↗
PubMed1980

Digitalis glycosides in serum, urine, and cerebrospinal fluid, determined with a commercial radioimmunoassay.

We evaluated a commercial (Clinical Assays, Inc.) 125I radioimmunoassay for digitoxin for use in measuring cardiac glycosides in serum, buffer, urine, and cerebrospinal-fluid samples. We also assessed interference of seven cardioactive metabolites of digitoxin, including digoxin, with the assay. The precision of the assay was adequate for all matrixes studied for glycoside concentrations less than 5 microgram/L. Reactivity in the assay was dependent on the nature of the matrix: buffer and serum samples containing digitoxin showed a stronger reactivity than did samples of urine and cerebrospinal fluid. Patients' samples must therefore be analyzed with a standard curve prepared by use of the same matrix. The digitoxosides of digitoxin showed a slightly higher reactivity in the assay than did digitoxin itself, but digitoxigenin showed a 50% lesser reactivity. Digoxin, its digitoxosides, and digoxigenin hardly react at all in the assay and so do not interfere with digitoxin determinations.

Animals↗
PubMed1976

Clinical use of digitalis glycosides.

The pharmacology of digitalis compounds is reviewed, and the clinical use of the cardiac glycosides is discussed with particular attention to the selection of patients for digitalis therapy and to a study of the usefulness of various methods to monitor digitalis therapy. The discussion includes pharmacokinetics, clinical considerations, and digitalis toxicity and its treatment. It is concluded that the digitalis glycosides remain the most useful and reliable drugs for producing a long-term increase in myocardial contractility. However, in view of the high frequency of toxicity, it is important to consider the possibility that these drugs may have been overused.

Digitalis Glycosides↗
PubMed1994

Terpenoid glycosides from the roots of Aster tataricus.

A new monoterpene glycoside, shionoside C, and a new oleanane-type triterpene glycoside, aster saponin G, were isolated from the roots of Aster tataricus. Their structures were elucidated on the basis of spectral and chemical methods. Shionoside C is L-endo-camphanol-8-3,5-isopropylidene-beta-D- apiofuranosyl-(1-6)-beta-D-glucopyranoside, aster saponin G is 3-O-[O-alpha-L-arabinopyranosyl-(1-6)-beta-D-glucopyranosyl]-2 beta, 3 beta, 16 alpha-trihydroxyolean-12-en-28-oic acid (asterogenic acid) 28-[O-beta-D-xylopyranosyl-(1-4)-alpha-L- rhamnopyranosyl-(1-2)-beta-D-xylopyranosyl]ester.

Bridged Bicyclo Compounds↗
PubMed1994

Extraordinary efficacy of 16 alpha-gitoxin, an ultra-short acting semi-synthetic digitalis glycoside.

The positive inotropic effect of 16 alpha-gitoxin was studied in 52 female and male healthy volunteers between the ages of 21 and 27 years and a body weight between 55 and 76 kg after the single i.v. injection or oral administration in doses between 2.5 and 15 mg. The inotropic effect was evaluated by the use of the systolic time intervals (left ventricular ejection time, LVET, and electromechanic systole, QS2) and by the QT-Interval of the ECG. The glycoside plasma level was measured simultaneously to the pharmacodynamic parameters by a radioimmunoassay, 16 alpha-gitoxin abbreviated dose-dependently the STI (LVET and QS2) for 30 (i.v.) or 15 ms (per os) and the QT interval for 35 ms. A mean plasma concentration of 401 ng/ml was measured 15 minutes after the i.v. injection of 5 mg and a mean plasma level of 402 ng/ml was measured 1 hour after the oral intake of 10 mg 16 alpha-gitoxin as an aqueous-ethanolic solution. The shortening of the STI-values and of the QT-interval correlated with the administered glycoside dose and with the AUC0-6-value. The AUC-values increased linearly with the administered dose. The ratio of the AUC0-6-values after i.v. or oral administration of 7.5 mg 16 alpha-gitoxin amounted to 0.673. Doses of 16 alpha-gitoxin which induce a maximum abbreviation of STI or QT did neither provoke a distinct decrease in heart rate nor cardiac disturbances. Sixteen-alpha-gitoxin develops a positive inotropic effect within a few minutes after i.v. injection and also after oral intake.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗
PubMedDate not supplied

[Effect of saccharol glycosides on energy metabolism in animals with abnormal carbohydrate tolerance].

A trial has been performed of a new sweetening agent saccharol, glycosides complex, on energy metabolism in rats with experimental alloxan diabetes. Elevated glucose level observed in rats with insulin insufficiency was associated with hexokinase activity inhibition and changes in the activity of the enzymes involved in glucose-6-phosphate transformation: enhanced activity of glucose-6-phosphatase and glucose-6-phosphate dehydrogenase against inhibition of phosphoglucomutase activity. Introduction of saccharose aggravated the above shifts in the rat liver, whereas saccharol possesses a protective action on hexokinase hepatic reaction and enzymes of glucose-6-phosphate conversion, reduced blood glucose. Positive changes induced by saccharol on energy metabolism in animals with insulin insufficiency can be attributed to the effect of saccharol glycosides.

Alloxan↗
PubMed1993

[Separation and identifying features of the cardiac aglycones and glycosides of Nerium oleander L. flowers by thin-layer chromatography].

The present work was aimed at extracting some cardiotonic glycosides from Nerium oleander L. (N.o.L.) flowers, free from phytosterols and their esters and at resolving themselves by thick- and thin-layer chromatography. This work may contribute to the scientific recognition of N.o.L. drugs in the field of forensic medicine. MATERIALS AND METHODS. Apparatus. Kieselgel F254 thin-layer (250 mu) and Kieselgel thick-layer (2 mm) glass plates were used. MATERIALS. Chromatographic solvents were used; detectors were p-toluene sulphonic acid (PTSA) and antimony trichloride (SbCl3). STANDARDS. The following standards were used: gitoxigenin, oleandrin, digitoxin, and stigmasterol. Standard solutions were prepared at a M-3 concentration. The solvent system is described in Table I. EXTRACT. The extract was prepared using a mixture of solvents (hexane-diethylether-acetic acis, 50:50:1 v/v). With this mixture we noted that, in thin-layer chromatography, the used standards remained at the origin, while phytosterols and their esters migrated. White flowers of N.o.L. were air dried in the shade at room temperature, powered, and macerated in hexane-diethylether acetic acid for 24 hours. After removal of the phytosterols the remacerating powder was further percolated using a chloroform-methanol mixture (1:1.7 v/v) in order to extract the aglycone and the cardiac glycosides. As the medium's thin-layer chromatogram showed the absence of corresponding spots to test samples, the chloroform-methanol media were combined and evaporated under vacuum. The residue was redissolved in the chloroform-methanol mixture. The obtained extract concentration consisted of 5 grammes of dried flowers in 1 milliliter of solution, called extract E (Fig. 1). RESULTS. The results are reported in Figures 2 and 4 and in Table II (see text for explanation of symbols). Extract E (Fig. 2) and the F1, F2, and F3 concentrated fractions were examined by thin-layer chromatography (Fig. 1 and 3). Only the F3 fraction revealed compounds with the same chromatographic path and colours (detected by PTSA and SbCL3) as the reference standards gitoxigenin, oleandrin, and digitoxin. This finding was confirmed by using five different solvent-systems (Fig. 4). DISCUSSION AND CONCLUSION. The present study shows that the cardiac steroids and other constituents of Nerium oleander's flowers are separated in three fractions by thick-layer chromatography free from phytosterols and their esters. This result may have useful implications in the fields of analytical toxicology and forensic medicine and potential application in clinical practice given that cytotoxic and antileukemic activities of the extracts from plants containing cardiac glucosides have been reported.

Cardiac Glycosides↗
PubMedDate not supplied

Antiproliferative effects on human peripheral blood mononuclear cells and inhibition of in vitro immunoglobulin synthesis by Podophyllotoxin (CPH86) and by semisynthetic lignan glycosides (CPH82).

A mixture of natural and semisynthetic (modified) glycosides from Podophyllum emodi (Proresid) has been used for many years in the treatment of rheumatoid arthritis, but its use is hampered by gastrointestinal side effects. Highly purified podophyllotoxin (CPH86) and a preparation containing two semisynthetic podophyllotoxin glycosides (CPH82) are currently being tested in clinical trials. In this study these drugs were shown to inhibit in vitro [3H]-thymidine uptake of human peripheral blood mononuclear cells stimulated by the mitogens concanavalin A, phytohemagglutinin and pokeweed mitogen. Complete inhibition was observed with CPH86 in concentrations > or = 20 ng/ml and with CPH82 in concentrations > or = 1 microgram/ml. In vitro production of IgG, IgM and IgA by PWM-stimulated cells cultured for 7 days was unaffected by 10 ng/ml CPH86 and 100 ng/ml CPH82, but was strongly inhibited by concentrations of CPH86 at > or = 20 ng/ml and CPH82 at > or = 1 microgram/ml. In conclusion, both CPH86 and CPH82 inhibit mitogen induced lymphocyte proliferation and immunoglobulin synthesis and the results may be of help in determining optimal dose levels if related to treatment effects.

Cell Division↗
PubMed1977

[Effect of treatment with cardiac glycosides and biologically active substances on the state of the lesser circulation according to the electrokymographic data].

Electrokymography was used to assess by pulmonary densograms and pulmonary artery pulse curves treatment-induced changes in cardiac contractility and lesser circulation in 455 patients with rheumatic heart disease and stage IIA, IIB, and III circulatory insufficiency. Treatment with cardiac glycosides in combination with metabolic preparations (ATP methionine, vitamin B12, inosine-F, and extract of the heart muscle) leads to a more conspicuous reduction in the symptoms of congestion in the lesser circulation than that encountered in treatment with cardiac glycosides alone. The reduction in these symptoms following treatment with ATP and heart-muscle extract may be explained not only by improved myocardial contractility but also by the direct vasodilating effect of adenyl compounds.

Adenosine Triphosphate↗
PubMed1977

[Evaluation of the clinical effect of treatment with cardiac glycosides under conditions of ambulatory observation].

Thirty-four patients with rheumatic heart disease and 22 with atherosclerotic and post-infarction cardiosclerosis, signs of stage I-IIB circulatory insufficiency, and disorders of cardiac rhythm (auricular fibrillation) were kept under out-patient care for periods of 6 to 42 months. They all received cardiac glycosides per os in a maintenance dose determined in the clinic after intravenous digitalization. Clinical and echocardiographic examination of the patients was conducted every 4 to 6 months. Depending on the effect of long-term digitalization, all patients were divided into clinical groups in which the causes of the disturbed compensation were determined. The importance of regular doctor's control over proper intake of the maintenance dose of glycosides and its correction depending on each concrete clinical situation is stressed.

Adult↗
PubMed2000

A novel high-pressure liquid-liquid extraction process for downstream processing in biotechnology: extraction of cardiac glycosides.

This investigation examines phase equilibrium phenomena that can be used to create two water-like solvents for liquid-liquid extraction in downstream processing in biotechnology: a completely miscible, binary liquid mixture of water and a hydrophilic organic solvent (e. g., an alcohol) reveals a liquid phase split, when it is pressurized with a "near-critical" gas (i.e., a substance which at ambient conditions is a gas, near its critical temperature). This phase split results in two hydrophilic liquid phases. Making use of this phenomenon in process development first requires research on the phase split phenomenon and, second, research on the feasibility of biomolecule extraction and separation. In this study, basic fluid phase equilibrium phenomena are briefly described. Then, experimental results are reported for the partitioning of small amounts of cardiac glycosides (digitoxin and digoxin) on coexisting liquid phases in the high-pressure, three-phase, vapor-liquid-liquid equilibrium of the ternary system of "near critical" CO(2) + water + 1-propanol, at 313 K and 333 K. Finally, a process for extraction and separation of the aforementioned glycosides by means of the high-pressure phase equilibrium phenomenon is discussed.

1-Propanol↗
PubMed2005

Aspects of glycosidic bond formation in aqueous solution: chemical bonding and the role of water.

A model of the specific acid-catalyzed glycosidic bond formation in liquid water at ambient conditions is studied based on constrained Car-Parrinello ab initio molecular dynamics. Specifically the reaction of alpha-D-glucopyranose and methanol is found to proceed by a D(N)A(N) mechanism. The D(N) step consists of a concerted protonation of the O(1) hydroxyl leaving group; this process results in the breaking of the C(1)-O(1) bond, and oxocarbenium ion formation involving C(1)=O(5). The second step, A(N), is the formation of the C(1)-O(m) glycosidic bond, deprotonation of the methanol hydroxyl group O(m)H(m), and re-formation of the C(1)-O(5) single bond. A focus of this study is the analysis of the electronic structure during this condensed phase reaction relying on both Boys/Wannier localized orbitals and the electron localization function ELF. This analysis allows the clear elucidation of the chemical bonding features of the intermediate bracketed by the D(N) and A(N) steps, which is a non-solvent equilibrated oxocarbenium cation. Most interestingly, it is found that the oxygen in the pyranose ring becomes "desolvated" upon double bond/oxocarbenium formation, whereas it is engaged in the hydrogen-bonded water network before and after this period. This demonstrates that hydrogen bonding and thus the aqueous solvent play an active role in this reaction implying that microsolvation studies in the gas phase, both theoretical and experimental, might lead to qualitatively different reaction mechanisms compared to solution.

Computer Simulation↗
PubMed1975

Systems approach to study of solute transport across membranes using suspension cultures of mammalian cells V: Uptake and release kinetics of cardiac glycosides by Burkitt lymphoma cells.

Mass transport studies with three cardiac glycosides in the Burkitt lymphoma cell system have provided significant examples of the factorization and quantification of the influences of serum-drug binding, membrane-drug binding, cell interior binding, and intrinsic membrane permeability upon the uptake and release kinetics of drugs in living cell systems. All of the data from the glycosides are in agreement with the general physical model involving the rapid equilibration of the solute within the cell after permeation through the rate-determining plasma membrane barrier. The transport of digitoxin was influenced by membrane and serum binding and that of digoxin was influenced by membrane binding. There was no binding of ouabain to the plasma membrane and serum. The variables in the uptake and release kinetic studies at pH 7.3 included the use of viable and heat-inactivated cells, fetal bovine serum levels, and temperature.

Burkitt Lymphoma↗
PubMedDate not supplied

Flavonoid glycosides and cannabinoids from the pollen of Cannabis sativa L.

Chemical investigation of the pollen grain collected from male plants of Cannabis sativa L. resulted in the isolation for the first time of two flavonol glycosides from the methanol extract, and the identification of 16 cannabinoids in the hexane extract. The two glycosides were identified as kaempferol 3-O-sophoroside and quercetin 3-O-sophoroside by spectroscopic methods including high-field two-dimensional NMR experiments. The characterisation of each cannabinoid was performed by GC-FID and GC-MS analyses and by comparison with both available reference cannabinoids and reported data. The identified cannabinoids were delta9-tetrahydrocannabiorcol, cannabidivarin, cannabicitran, delta9-tetrahydrocannabivarin, cannabicyclol, cannabidiol, cannabichromene, delta9-tetrahydrocannabinol, cannabigerol, cannabinol, dihydrocannabinol, cannabielsoin, 6a, 7, 10a-trihydroxytetrahydrocannabinol, 9, 10-epoxycannabitriol, 10-O-ethylcannabitriol, and 7, 8-dehydro-10-O-ethylcannabitriol.

Cannabinoids↗