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1. The effect of theophylline on ion transport was examined using an in vitro short-circuited preparation of lizard colon. 2. Theophylline increased short circuit current (Isc) and transmural potential difference (PD). This increase caused by theophylline was accompanied by a small increase in transmural conductance (Gt). 3. Theophylline did not inhibit the absorption of Na+ but reversed Cl- absorption to secretion. This latter effect was due to an increase of the serosal-to-mucosal flux of Cl-. 4. Ion substitution experiments revealed that the effect of theophylline was Na+- and HCO3(-)-dependent and that these ions were required in the bathing solution. 5. These results with lizard colon are compared with those reported for mammalian colon and the mechanism of theophylline-induced Cl- secretion in these epithelia is discussed.

Electrical parameters and unidirectional Na+ and Cl- fluxes were determined in vitro across the duodenum, ileum and colon of lizard (Gallotia galloti). Electrical potential difference (PD) and short circuit current (Isc) were low in the three segments studied, whilst tissue conductance (Gt) was high. A net active transport of Na+ and Cl- was observed in the three segments. Net Na+ absorption was higher across duodenum and ileum than across the colon, while net Cl- absorption was similar in duodenum, ileum and colon. Ouabain virtually abolished Isc, PD and net Na+ and Cl- fluxes in all the segments. Amiloride abolished net Cl- flux in duodenum, ileum and colon, whereas net Na+ flux was abolished in colon but decreased in duodenum and ileum. PD and Isc were not affected by the presence of the diuretic.

Simultaneous measurements of the electric potential difference and the short-circuit current intensity were taken, as well as measurements of unidirectional fluxes of sodium and chloride in the posterior intestine of Blennius parvicornis fish. On incubating the tissue in standard Ringer solution, a potential difference of--0.9 mV, a mean net flux of sodium of 2.49 mu Eq/h x cm2 were obtained. In the absence of sodium (choline as substitute), the net chloride flux and the Isc were completely blocked. In the absence of chloride (isocyanate as substitute) the net sodium flux and the Isc were equally blocked. Ouabain lessened the sodium and chloride fluxes in the mucosa-serosa direction to the point of nulling the net fluxes of both ions. The values of the bioelectric parameters were also blocked in the presence of this inhibitor. Acetazolamide did not significantly affect the values of either the unidirectional fluxes or the net fluxes of sodium and chloride. Nor did it affect the values of the bioelectric parameters. A mechanism for the absorption of sodium and chloride is proposed in which these ions enter the cell in a coupled form and in 1:1 proportion, the transport being independent of the bicarbonate ion.

1. Electrical parameters and transepithelial glucose and galactose transport were determined in vitro across anterior and posterior intestine of the culture fish Sparus aurata. 2. Electrical potential difference (PD) and short-circuit current (Isc) were serosa-positive in anterior intestine, while they were serosa-negative or near zero in posterior intestine. 3. Tissue conductance (Gt) was higher in posterior than in anterior intestine. In both parts it was decreased when the Na ion was omitted in mucosal and serosal reservoirs. 4. Addition of glucose or galactose to the mucosal side of intestine caused an increase in PD and Isc in posterior intestine but did not significantly change PD and Isc in anterior intestine. 5. Isotopic flux of glucose and galactose measurements in short-circuit conditions showed a net active glucose and galactose absorption in posterior intestine, while in anterior intestine active transport of glucose or galactose was not observed. 6. The net transport of glucose and galactose in posterior intestine was decreased to zero in the absence of Na in mucosal and serosal reservoirs or in the presence of ouabain (1 mM) in serosal solution.

1. Ionic fluxes of sodium and chloride across lizard colon mucosa were measured and compared with the electrical characteristics of the tissue under voltage-clamped conditions. 2. In a Ringer-bicarbonate solution there was both a net sodium flux (JNanet) and a net chloride flux (JClnet) from mucosa to serosa. The net flux residual (JR) was near zero, indicating that net sodium and chloride transport is the result of an electrically neutral transport mechanism. 3. In the presence of sodium, the net chloride flux was abolished and the short-circuit current (Isc) and the electrical potential difference (PD) were unchanged. In the absence of chloride the net sodium flux was abolished and the short-circuit current and electrical potential difference were not modified. 4. From an analysis of the effects of the inhibitors, furosemide, amiloride and disulfonic stilbene (DIDS), a plausible model was developed to explain the characteristics of sodium and chloride absorption.

Electrical parameters and transepithelial Na+ and galactose transport were determined in vitro across isolated duodenum of Lacerta galloti lizard. Electrical potential difference (PD) and short-circuit current (Isc) were dependent on the presence of Na+ in the bathing solutions. PD and Isc were affected by addition of galactose to the mucosal solution. Isotopic flux of Na+ measurements across short-circuited duodenum showed a net active Na+ absorption. The net flux of Na+ (JNa+net) accounted for the observed Isc. Both (JNa+net) and Isc were increased by the addition of galactose 5 mM to the mucosal solution. Isotopic flux galactose measurements in open-circuit conditions showed a net active galactose absorption. The net transport of galactose was decreased to zero in the absence of Na+ in mucosal and serosal reservoirs. Galactose has been used to induce changes in short-circuit current (delta Isc) across intestine. delta Isc was a hyperbolic function of galactose concentration characterized by the parameters Vmax (maximum change in delta Isc) and Km (concentration needed to attain a velocity equal to half the Vmax).

The results of a clinical study to evaluate the use of glucose-1-phosphate for phosphate supplementation to a group of 8 surgical patients receiving standardized total parenteral nutrition are presented. Average phosphate (p + 0.001), calcium (NS) and magnesium (NS) plasma concentrations increased during total parenteral nutrition. Positive average daily balances were obtained: 8.1 + 14.8, 4.5 + 4.3 and 1.8 + 3.3 mmol/day for phosphate, calcium and magnesium respectively. These findings support the hypothesis of higher bioavailability of glucose-1-phosphate with respect to inorganic phosphate. On the other hand, hyperphosphatemia was a frequent situation (45.8%); this fact suggests the need for reviewing phosphate daily requirements when supplied in the form of glucose-1-phosphate.

The outcome of 63 children with non-B acute lymphoblastic leukemia treated with ALL-BFM 83 protocol is analyzed. 95% achieved complete remission with the initial treatment. For the entire group the event free survival (EFS) was 66% (+/- 9%) at 48 months. These results were close to those obtained by the BFM group. Haematological toxicity was the main adverse effect, but there where no therapy related deaths. Persistence of more than 1,000 blast cells per microl in peripheral blood after 7th days of prednisone monotherapy, and spleen size greater than or equal to 5 cm under the costal margin, were identified as independent risk factors of high significance. The EFS in patients with poor clinical response to steroids (greater than or equal to 1,000 blast/microl at day 8) was 22% (+/- 18%), instead of 69% (+/- 12%) in those with adequate response.