Suppression of the osmoinduced proline response of rapeseed leaf discs by polyamines.

Rapeseed leaf discs (RLD) subjected to upshock osmotic stress accumulate proline (Pro). Di- and polyamines (PA) supplied to the external medium suppressed Pro accumulation. These effects were dependent not only on diamine and PA concentrations but also on their cationic charge. The suppression of Pro accumulation required that diamine and PA be taken up and further accumulated in the leaf tissues. Glycine betaine (GB) also inhibited Pro accumulation, with the effects of GB and PA being additive. Experiments to elucidate the mechanism(s) responsible for the inhibitory effect of spermine (Spm) indicated that it could be simulated with methionine sulfoximine (MSO), a potent inhibitor of glutamine synthetase. The inhibitory effects of Spm and MSO were both alleviated by supplying glutamine to the RLD. In addition, Spm as well as MSO increased glutamate content, indicating that these compounds could inhibit the conversion of glutamate to proline. A comparison of the changes in chlorophyll and protein content of RLD osmotreated with or without added Spm indicates that this PA behaves as an antisenescent compound, preventing chlorophyll breakdown and proteolysis and hence the conversion of amino acids to Pro. Since the PA concentrations used in this work were much higher than the endogenous concentrations in RLD, the significance of PA under osmotic stress remains unclear. This study shows, however, that PA can suppress Pro accumulation.

[Post-menopausal endometriosis developed during tamoxifen treatment]. / Endométriose post-ménopausique développée sous tamoxifène.

The authors report a case of endometriosis (adenomyosis + endometrioma) which occurred in a female patient aged 69 years, who had undergone the menopause 15 years previously and who had been taking Tamoxifen for 7 years as an adjuvant treatment for cancer of the breast. Tamoxifen, a non-steroidal anti-estrogen derived from diethylstilbestrol, has a variable antagonist/agonist so that estrogenic stimulation of the female genital tract may occur, particularly of the endometrial mucosa. The reactivation of the endometriosic foci which had become quiescent under the impact of the natural menopause, which, by iatrogenic analogy is included in the series of paradoxical uterine effects of tamoxifen.

Sequential combination of 5-fluorouracil, cis-platinum and irradiation. 1. Advanced head and neck cancers.

Based on the synergistic action of 5-fluorouracil (5-FUra), cis-dichlorodiamminoplatinum(II) (cis-DDP) and gamma-rays, which was suggested in experiments on murine tumours, a sequential treatment combining irradiation and chemotherapy for human solid tumours known to be resistant to conventional treatments has been developed. A pilot study was carried out on 30 patients with recurring head and neck cancers previously treated by radiotherapy and surgery. The good tolerance and the initial results justified applying this protocol to previously untreated cases. The second study involved 40 patients with stage III and IV tumours. After 3 cycles of combined radio- and chemotherapy followed by a conventional radiotherapy, 78% were good responders (51% in complete remission). Oropharynx and oral cavity, without base of tongue, have a 51% actuarial survival at 3 years when they achieved an early complete remission.

Effect of halothane on diaphragmatic muscle function in pentobarbital-anesthetized dogs.

The mechanism underlying the decrease in minute ventilation (VE) observed under halothane anesthesia was investigated in nine spontaneously breathing dogs. Anesthesia was induced with pentobarbital sodium and was maintained with halothane. Inspired fraction of halothane (FIhal) was increased every 30 min, from 0.005 to 0.02. VE decreased from 8.1 +/- 0.9 to 4.8 +/- 0.4 l . min-1 (P less than 0.001), as FIhal increased from 0 to 0.02. This resulted from a decrease in both mean inspiratory flow (VT/TI) and the duty ratio (TI/TTOT). Transdiaphragmatic pressure (Pdi) and the integrated electrical activity of both hemidiaphragms (Edi) were measured during normal breathing, and during breathing against closed airways (P0di, E0di), in order to obtain an index of the inspiratory neuromuscular output of the diaphragm. With increasing FIhal, there was a significant decrease in Pdi, P0di, Edi, and E0di. The authors measured Pdi and Edi generated during supramaximal stimulation of the two phrenic nerves (PSdi, Esdi) at frequencies of 10, 20, 50, and 100 Hz, in order to eliminate in this decrease the role played by a decrease in the neural drive to breathing. PSdi and ESdi decreased significantly with increasing FIhal, and had not returned to the control values 30 min after discontinuation of halothane administration. The authors conclude that, in pentobarbital-anesthetized dogs, halothane is responsible for a diaphragmatic dysfunction, which may be located either at the neuromuscular junction, on the contractile processes of the muscle, or on both, and for a decrease in the activation time of the inspiratory muscles. Both of these effects contribute to the decrease in VE observed under halothane anesthesia.