[Usefulness of erythromycin in severe postoperative gastroparesis]. / Utilidad de la eritromicina en la gastroparesia postquirúrgica severa.

Erythromycin has recently been shown to exert a great effect on gastroduodenal motor activity. This prokinetic action may be clinically useful in patients with gastrointestinal hypomotility such as diabetic or postsurgical gastroparesis. The case of a diabetic patient who underwent antrectomy Billroth II for gastric cancer is presented. Severe gastroparesis appeared after surgery and nasogastric aspiration could not be removed, although the patient was treated with metoclopramide, and glucose levels, hydroelectrolytic balance and nutritional status were corrected. Forty-one days after the first operation, a second gastrectomy with Bilroth II reconstruction was performed because of supposed anastomotic narrowing, which was not confirmed at surgery. Fourteen days later, i.v. erythromycin (200 mg/4h) was started owing to gastroparesis persistence. Six days after treatment the patient tolerated oral ingestion. Prokinetic drugs constitute the specific therapy for gastroparesis. Metoclopramide is the most used, although its efficacy is limited. In the last few years, erythromycin has proved to have a powerful effect on gastroduodenal motility. This effect is mediated, at least in part, by its motilin stimulating activity accelerating gastric emptying. Our patient completely recovered from gastroparesis after erythromycin treatment. Recent results of erythromycin therapy in these patients have been promising, despite the difficult management involved.

Triterpene saponins from Cylicodiscus gabunensis.

Four new saponins were isolated from the alcoholic extract of the bark of Cylicodiscus gabunensis by means of flash chromatography. They were characterized on the basis of spectral and chemical data as 3-O-beta-[alpha-L-arabinopyranosyl (1----2),alpha-L-arabinopyranosyl(1----3),beta-D-glucopyranosyl(1- ---)] maslinic acid-28-[beta-D-glucopyranosyl(1----6),beta-D-glucopyranosyl(1----2),alp ha-L- rhamnopyranosyl(1----)] ester; 3-O-beta-[alpha-L-arabinopyranosyl(1----2),alpha-L-arabinopyran osyl (1----3),beta-D-glucopyranosyl(1----)]maslinic acid-28-[beta-D-glucopyranosyl(1----2),alpha-L-rhamnopyranosyl(1----)] ester, 3-O-beta-[alpha-L-arabinopyranosyl(1----2),alpha-L-arabinopyran osyl (1----3),beta-D-glucopyranosyl(1----)]maslinic acid and 3-O-beta(alpha-L-arabinopyranosyl(1----3),beta-D-glucopyranosyl (1----)] cylicodiscic acid.

Hydrocarbon recovery and biocompatibility of solvents for extraction from cultures of Botryococcus braunii.

Various water-immiscible solvents were tested for biocompatibility and hydrocarbon recovery under different contact conditions with the hydrocarbon-rich microalga Botryococcus braunii. Eighteen solvents were first selected from a database of 1500 compounds (compiled for solvent selection for ethanol recovery from Saccharomyces cerevisiae fermentation). Nine of these candidate solvents were shown to be biocompatible with B. braunii following short contact times. This biocompatibility tends to be associated with high molecular weights and high boiling points but strongly depends on solvent chemical structure. A low polarity is essential to biocompatibility and calculated octanol-water partition coefficients, or capacity factors determined by reversed-phase high-performance liquid chromatography (HPLC), are suitable predictors of biocompatibility with B. braunii. High recoveries of hydrocarbons directly from the algal culture require relatively polar solvents and are, therefore, inimical with maintenance of cell viability. The inaccessibility of weakly polar solvents to the cell surface appears to protect the algae but also prevents substantial recovery of the hydrocarbons stored in B. braunii outer walls. In order to achieve a high recovery, contact with the solvent must be carried out on algae concentrated by filtration. Then, a large fraction of B. braunii hydrocarbons can be recovered, after a short contact time, without impairing cell viability. Under these conditions, the pertinent solvent property is affinity for the nonpolar hydrocarbons, and the highest recovery yield, approximately 70% after contact for 30 min, is achieved with hexane.

Studies on batch and continuous cultures of Botryococcus braunii: hydrocarbon production in relation to physiological state, cell ultrastructure, and phosphate nutrition.

The growth of the hydrocarbon-rich alga Botryococcus braunii was studied under "air-lift" conditions using batch and continuous cultures. Large variations in the physiological state of B. braunii were achieved in batch cultures and in continuous cultures with various dilution rates. The possible effects of these variations upon hydrocarbons (nature, relative abundance, location, level, productivity) and also on the production of exocellular polysaccharides were examined. The relationships between the physiological state of B. braunii and its hydrocarbon and polysaccharide production were discussed and compared with those generally observed in unicellular algae. The factors giving rise to the transition from high to low productivity stages were considered. To this end we examined, at first, the variations in cell ultrastructure and the resulting degeneration occurring during batch cultures. Afterward the parallel changes in some parameters of the medium (pH, phosphate level) were determined and their possible relationships with B. braunii growth and hydrocarbon production were discussed. The main features of phosphate nutrition in B. braunii and its effects on hydrocarbons were finally examined.