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Biomedical subjects

C Lavaud

Publications and source records attributed to C Lavaud.

At least 37 records · Page 2Linked to original sources
PubMed1994

Triterpene saponins from Myrsine pellucida.

Quercitol, five saponins and 3-O-(6'-O-palmitoyl) beta-D-glucopyranosyl stigmasterol were isolated from the stem bark of Myrisine pellucida. These compounds are described for the first time in this plant and their structures were determined using a combination of 1H and 13C NMR, and mass spectroscopy. The two saponins are new compounds, 3-O-(alpha-L-rhamnopyranosyl (1-->2) beta-D-glucopyranosyl (1-->4) alpha-L-arabinopyranosyl) cyclamiretin A and 3-O-(beta-D-xylopyranosyl) (1-->2) beta-D-glucopyranosyl (1-->4) [beta-D-glucopyranosyl (1-->2)] alpha-L-arabinopyranosyl) cyclamiretin D.

Bolivia↗
PubMed1993

Triterpenoid saponins from Opilia celtidifolia.

Six saponins were isolated from leaves and stems of Opilia celtidifolia and their structures established. These saponins are described for the first time in this plant. One of them is a new saponin: 3-O-[alpha-L-rhamnopyranosyl(1-->3) beta-D-glucuronopyranosyl]-28-O-beta-D-glucopyranosyl-hederagen in.

Africa↗
PubMed1992

Triterpenoids and their glycosides from the bark of Schefflera octophylla.

A new triterpene and its glycosides were isolated from the bark of Schefflera octophylla together with asiatic acid and asiaticoside. Based on spectroscopic data, especially 2DNMR, and chemical transformations the structures of the new compounds were determined as 3 alpha-hydroxy-urs-12-ene-23,28-dioic acid and 3 alpha-hydroxy-urs-12-ene-23,28-dioic acid 28-O-[alpha-L-rhamnopyranosyl (1----4)-O-beta-D-glucopyranosyl (1----6)]-beta-D-glucopyranoside. For the first time asiaticoside was isolated from a plant other than Centella asiatica.

Carbohydrate Sequence↗
PubMed1992

Withanolide glycosides from Dunalia australis.

Four new withanolide glycosides, (20R,22R)-O-(3)-[beta-D- xylopyranosyl(1----3), beta-D-xylopyranosyl(1----4)]-beta-D-glucopyranosyl-3 beta,20-dihydroxy-1 alpha-acetoxy-witha-5,24-dienolide, (20R,22R)-O-(3)-[beta-D-xylopyranosyl(1----3), beta-D-glucopyranosyl(1----4)]-beta-D-glucopyranosyl-3 beta,20-dihydroxy-1 alpha-acetoxy-witha-5,24-dienolide, (20R,22R)-O-(3)-[beta-D- glucopyranosyl(1----3), beta-D-glucopyranosyl(1----4)]-beta-D-glucopyranosyl- 3 beta,20-dihydroxy-1 alpha-acetoxy-witha-5,24-dienolide and (20R,22R)-O-(3)-[beta-D-glucopyranosyl(1----3), beta-D- glucopyranosyl(1----4)]-beta-D-glucopyranosyl-3 beta, 12 beta,20-trihydroxy- 1 alpha,acetoxy-witha-5,24-dienolide, named dunawithanines C, D, E and F, respectively, were isolated from Dunalia australis. Their structures were elucidated on the basis of spectral and chemical evidence, especially NMR data of the peracetates.

Carbohydrate Sequence↗
PubMed1992

Saponins from Verbascum nigrum.

Two triterpene saponins have been isolated from the inflorescences of Verbascum nigrum. Their structures were determined by chemical and spectral methods as 3-O-([alpha-L-rhamnosyl-(1-->4)-(beta-D-glucopyranosyl-(1-->3)]-be ta-D-glucopyranosyl]-(1-->2)-beta-fucopyranosyl)-13 beta,28-epoxyolean-11-ene-3 beta,23-diol and 3-O-([alpha-L-rhamnosyl-(1-->4)-(beta-D-glucopyranosyl-(1-->3)-bet a-D- glucopyranosyl]-(1-->2)-beta-fucopyranosyl)-11-methoxy-olean-12-en e-3 beta,23,28-triol.

Carbohydrate Sequence↗
PubMed1992

Saponins from Steganotaenia araliacea.

Six saponins have been isolated and identified from the leaves of Steganotaenia araliacea. They were identified as 3-O-[beta-D-galactopyranosyl(1----2)-(beta-D-galactopyranosyl (1----3))-beta-D-glucuronopyranosyl]-21-O-tigloyl and -21-O-angeloyl-R1-barrigenol, 3-O-[beta-D-glucopyranosyl(1----2)-(beta-D-xylopyranosyl (1----3))-beta-D-glucuronopyranosyl]-21-O-tigloyl and -21-O-angeloyl-R1-barrigenol, 3-O-[beta-D-glucopyranosyl(1----2)-(beta-D-glucopyranosyl-(1----3))-(alp ha-L- rhamnopyranosyl(1----4))-beta-D-glucopyranosyl] steganogenin and 3-O-[(beta-D-galactopyranosyl(1----2)-beta-D-glucuronopyranosyl]-2 8-O- beta-D-glucopyranosyl olean-12-ene-28-oic acid. Steganogenin is a new 17,22-seco-oleanolic acid derivative. The structures of the saponins were established by analysis of their 1H and 13C NMR spectra with the help of 2D-experiments and by Californium Plasma Desorption Mass Spectrometry.

Carbohydrate Sequence↗
PubMed1992

Saponins from stem bark of Petersianthus macrocarpus.

Two bioactive saponins were isolated from the stem bark of Petersianthus macrocarpus. Their structures were elucidated by chemical degradations and by a combination of 2D NMR techniques and by Californium plasma desorption mass spectrometry. They are 3-O-([beta-D-galactopyranosyl (1-->2)][beta-D-galactopyranosyl (1-->3)]- beta-D-glucuronopyranosyl)-21-O-[3-(3-tigloyloxynilic acid)-4-tigloyloxy- alpha-L-arabinopyranosyl] barringtogenol C and 3-O-([beta-D-galactopyranosyl (1-->2)][beta-D-galactopyranosyl (1-->3)]-beta-D-glucuronopyranosyl)-28-O-alpha-L-rhamnopyranosyl barringtogenol C-21-O-benzoate. The absolute configuration of nilic acid was determined by partial synthesis. 3,3'-Dimethoxy ellagic acid and 3,3'-dimethoxy-4-O-beta-D- glucopyranosyl ellagic acid were also isolated.

Carbohydrate Sequence↗
PubMed1991

Triterpene saponins from Verbascum songaricum.

Songarosaponin A, B and C isolated from the aerial parts of Verbascum songaricum were shown to be 3-O-[alpha-L-rhamnopyranosyl-(1----4)-beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)-beta-D-fucopyranosyl]-olea-11,13-die ne-3 beta-23,28-triol, 3-0-[alpha-L-rhamnopyranosyl-(1----4)-beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)]-beta-D-fucopyranosyl]-olea-1 1-ene-3 beta-13,23,28-tetrol and 3-O-[beta-D-glucopyranosyl-(1----4)]-[beta-D-glucopyranosyl-(1----3)]-[b eta-D-glucopyranosyl-(1----2)]-beta-D-fucopyranosyl]-13 beta,28-epoxyolea-11-ene-3 beta,23-diol.

Carbohydrate Sequence↗
PubMed1991

Triterpenoid glycosides from the bark of Mimosa tenuiflora.

Two new saponins were isolated from Mimosa tenuiflora and their structures established as 3-O-[alpha-L-rhamnopyranosyl(1----2)-beta-D-glucopyranosyl-(1----3]-(alp ha-L- arabinopyranosyl-(1----4]-beta-D-xylopyranosyl-(1----2)]-[beta-D- xylopyranosyl-(1----4)]-beta-D-glucopyranosyl)-28-O-alpha-L-rhamnopyrano syl oleanolic acid and 3-O-[alpha-L-rhamnopyranosyl-(1----2)-beta-D-glucopyranosyl-(1----3]-(al pha- L-arabinopyranosyl-(1----4]beta-D-xylopyranosyl-(1----2)]-[beta-D- xylopyranosyl-(1----4)]-beta-D-glucopyranosyl) oleanolic acid.

Carbohydrate Sequence↗
PubMed1986

What changes can be expected during high frequency jet ventilation when the rate of ventilation, the I:E ratio and the driving pressure are modified? A laboratory study.

Changes in minute ventilation, tracheal airway pressure and lung volume have been measured using a jet ventilator (VS 600) during different rates of ventilation, I:E ratios and driving pressures. A lung model with a slightly increased compliance and an increased airway resistance was used. Five rates of ventilation (from 60 to 230 b.p.m.), three I:E ratios (0.25, 0.43, 0.67) and three driving pressures (200, 300 and 400 kPa) were studied. The increases in the rate of ventilation did not modify minute ventilation significantly, decreased peak airway pressure only slightly and increased end-expiratory pressure and lung volume. The increases in I:E ratio produced increases in minute ventilation, peak airway pressure, end-expiratory pressure and lung volume. The increases in driving pressure induced changes similar to those produced by the alterations in I:E ratio.

Airway Resistance↗
PubMed1985

Jet ventilation using low or high frequencies, during bronchoscopy.

Jet ventilation, through a bronchoscope, was evaluated using a lung model (normal compliance and increased airway resistance). Three I/E ratios (0.25, 0.43, 0.67) and seven rates of ventilation (from 20 to 230 cycles per min (c min-1) were studied with the bronchoscope either unoccluded or partially occluded by a telescope. Increases in I/E ratio induced increases in minute ventilation, peak airway pressure, end-expiratory pressure and lung volume. Increase in the rate of ventilation decreased peak airway pressure, increased end-expiratory pressure and lung volume; minute ventilation increased in parallel with the increase in the rate of ventilation or remained constant when a high I/E ratio was used. The introduction of the telescope reduced minute ventilation, as a result of a decrease in the amount of air entrained, and increased end-expiratory pressure and lung volume. The risk of barotrauma as a result of high peak pressure is reduced during high frequency jet ventilation, but the increase in lung volume, particularly when the telescope is introduced, may be of clinical importance.

Bronchoscopy↗
PubMed1980

[Evaluation of hemodialysis systems (author's transl)].

Since March 1973, approval procedure for hemodialysis systems devices is mandatory in France. Basically it controls the minimum requirements to insure the effective, safe performance of these devices in the treatment of end stage renal disease. They include dialysing fluid systems, monitoring equipment and dialyzers. We have controlled 28 dialysate delivery system monitors and 21 dialyzer models. During the approval procedure a high rate of cases which do not meet the minimal requirements, were observed: 61 p. cent for the identification of the device, 72 p. cent for the safe electrical current limits (French National Standard), 83 p. cent for the monitoring and 22 p. cent for the duration (1,000 hours for center utilisation, 1,500 hours for home utilisation). Better results were found with dialyzer performances. Ultrafiltration flow rate and solute dialysance measured in vitro under clinical conditions of flow rates and pressures correlated well with the values claimed by the manufacturers. Problems encountered during the approval procedure stemmed from the lack of National and International Standard for hemodialysis systems and the poor compliance of the manufacturers to "good manufacturing practice" rules.

Clinical Trials as Topic↗
PubMed1975

Essay of any ventilators by means of a pulmonary model with adjustable resistance, compliance and vital capacity.

After a critical study of classic lung models, showing that linear resistances are not faithful nor justified and that pneumotachograph is not a good measuring apparatus because of its inaccuracy (it changes calibration according to the nature of gas mixture and needs integration to determine volumes), authors present their own lung "model". In this model, it is possible to adjust resistance, compliance, vital capacity and residual volume. Parabolic resistances are used, because they more approach physiologic ones. Building of resistances (diaphragms), compliances (rigid tanks with adjustable elements), vital capacity (elastic membrane between two grills) is simple to realise and easy to reproduce. Measures of pressure and volume are given directly by gauges and are insensitive to gas nature, which is important in respiratory physiology. Flow-rates are deducted from volume values. The lung model can be used in a twin-cell shape to show the effects of artificial ventilation in case of pulmonary asymmetry. Examples given underline the interest of having a model with resistances easy to build and an adjustable vital capacity.

Airway Resistance↗