RESUMEN

We propose and demonstrate asymmetric 10 Gbit/s upstream--100 Gbit/s downstream per wavelength colorless WDM/TDM PON using a novel hybrid-silicon chip integrating two tunable lasers. The first laser is directly modulated in burst mode for upstream transmission over up to 25 km of standard single mode fiber and error free transmission over 4 channels across the C-band is demonstrated. The second tunable laser is successfully used as local oscillator in a coherent receiver across the C-band simultaneously operating with the presence of 80 downstream co-channels.

RESUMEN

The prereplicative phase-related changes in spontaneous and taurocholate-induced biliary lipid secretion were studied in anaesthetized male Wistar rats (250 g). Rats underwent two-thirds hepatectomy 1, 6 or 12 h before starting to collect bile samples. As compared with non-hepatectomized rats, biliary lipid secretion was increased at 1 h after hepatectomy and then restored to values similar to the control group up to 12 h after hepatectomy. In separate experiments, taurocholate was infused (200 nmol/min/g calculated liver weight) through the jugular vein over 80 min. Both taurocholate-induced bile flow and bile acid output were similar in control and hepatectomized rats, regardless of the time of the prereplicative phase considered. By contrast, taurocholate-induced lecithin and cholesterol outputs were markedly modified. The former was lowered throughout the prereplicative phase, whereas the latter increased at 6 h and decreased at 12 h. In summary, these results indicate that shortly after hepatectomy bile acid-induced biliary lipid secretion is profoundly modified, probably due to changes in the plasma membrane involved in preparing the hepatocyte to enter the cell cycle.

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RESUMEN

1. During the pre-replicative phase of the regenerating rat liver some interesting changes occur, which might selectively modify some mechanisms involved in bile formation, such as those responsible for the hypercholeretic effect of ursodeoxycholic acid. The aim of the present work was to gain information on this point. 2. Anaesthetized male Wistar rats (approximately 250 g) were used. The animals underwent two-thirds hepatectomy 1, 6 or 12 h before collection of bile samples was begun. Very early after hepatectomy (1 h) spontaneous bile flow and bile acid output were increased. Both returned to values not significantly different from those of the controls at 6 h. Bile flow increased again at the end of the pre-replicative phase. Taurocholate infusion (200 nmol min-1 g-1 calculated liver weight) induced increases in bile flow and bile acid output that were similar in both the control and hepatectomized rats, regardless of the time of the pre-replicative phase considered. 3. Cholic acid and ursodeoxycholic acid were infused (300 nmol min-1 g-1 calculated liver weight) into control and partially hepatectomized rats (at the mid-point of the pre-replicative phase, i.e. 6 h after surgical liver resection). Cholic acid-induced bile flow, bile acid and bicarbonate output expressed per g of remaining liver were similar in control and in hepatectomized rats. By contrast, ursodeoxycholic acid-induced choleresis were profoundly altered during the pre-replicative phase. As expressed per g of remaining liver, bile flow was markedly reduced (-17%, P less than 0.05), in spite of total bile acid output being greatly increased (+ 148%, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

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