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Notes: It was shown in previous studies that the giant freshwater alga Chara corallina does not control its Na+-dependent Pi uptake by monitoring the internal Pi concentration and it was hypothesized that Chara may instead detect changes in Pi supply from the environment. The present work investigated the conditions that control the induction and inactivation of high affinity Na+/Pi influx in Chara. Withdrawal of Pi from the external medium resulted in a gradual increase in the rate of uptake measured immediately after Pi was resupplied. The increase continued for at least 7 d of starvation. In the initial stages, 0·5 or 1 µm Pi were more effective at inducing transport activity than no Pi, suggesting that low levels of Pi are actually required for induction. The high Na+-dependent Pi uptake observed in Pi-starved cells was inactivated by treatment with as little as 1 µm Pi over 6 d. External Na+ plays a major role in controlling the capacity for Na+/Pi cotransport activity, and in the absence of Na+, both induction and inactivation were either delayed or abolished. Na+ starvation stimulated Na+ uptake even though there were no measurable changes in the concentrations of Na+, or of K+ or Pi in either the vacuole or cytoplasm. It was concluded that both substrate (Pi) and driver ion (Na+) are required at adequate concentrations for the induction of the cotransporter. In the case of Pi, it was suggested that passive leakage of Pi from the cell into the apoplast is sufficient for this purpose but that supplementation by up to 1 µm Pi is more effective at the earlier stage. A mechanism for sensing the external supply of Pi is proposed.

Notes: Changes in inorganic phosphate (Pi) concentrations in barley leaves during growth of plants with sufficient or deficient supplies of Pi were studied. Measurements of the Pi distribution from subcellular levels to the leaf tissue level under the same experimental conditions allowed us to analyse the relationship between the Pi homeostasis of various compartments and Pi re-translocation in the whole plant. Under Pi deficiency, the finding of growth-dependent changes in the Pi concentrations of whole leaves established that Pi was re-translocated from the older leaves to the young leaves. Translocation of 32Pi was also confirmed with an ‘imaging plate’ system, which made it possible to follow Pi movement in the same plantlet. To analyse the mechanism of Pi re-translocation, the Pi distribution amongst various compartments of the leaves was measured. Under Pi deficiency, the cytoplasmic Pi concentration of the first leaf remained constant until 16d after sowing, while vacuolar Pi was completely exhausted after 8 to 10d. Exhaustion of vacuolar Pi in the first leaf coincided with the appearance of the second leaf. The Pi concentration in the apoplast changed similarly to that of the whole leaf. However, the apoplastic Pi concentration was affected to some extent by the vacuolar Pi concentration and the growth of the younger leaf, because the main change in apoplastic Pi concentration coincided with the time of the disappearance of the vacuolar Pi and the appearance of the younger leaf. The Pi concentration in the apoplast was about 0.1 to I molm−3, even in the absence of Pi, which was much higher than that in the usual soil environment (a few mmolin−3). This suggests that the Pi absorbed by root cells is concentrated in the transport process from the root to the leaf apoplast. The content of Pi in the xylem exudate was constant irrespective of growth culture conditions. The root may be functioning as the constant Pi supplier to the above tissues.

Notes: Carbon transport across the plasma membrane, and carbon fixation were measured in perfused Chara internodal cells. These parameters were measured in external media of pH 5·5 and pH 8·5, where CO2 and HCO3- are, respectively, the predominant carbon species in both light and dark conditions. Cells perfused with medium containing ATP could utilize both CO2 and HCO3- from the external medium in the light. Photosynthetic carbon fixation activity was always higher at pH 5·5 than at pH 8·5. When cells were perfused either with medium containing hexokinase and 2-deoxyglucose to deplete ATP from the cytosol (HK medium) or with medium containing vanadate, a specific inhibitor of the plasma membrane H+-ATPase (V medium), photosynthetic carbon fixation was strongly inhibited at both pH 5·5 and 8·5. Perfusion of cells with medium containing pyruvate kinase and phosphoenolpyruvate (PEP) to maximally activate the H+-ATPase (PK medium), stimulated the photosynthetic carbon fixation activities. Oxygen evolution of isolated chloroplasts and the carbon fixation of cells supplied 14C intracellularly were not inhibited by perfusion media containing either hexokinase and 2-deoxyglucose or vanadate. The results indicate that Chara cells possess CO2 and HCO3- transport systems energized by ATP and sensitive to vanadate in the light. In the dark, intact cells also fix carbon. By contrast, in cells perfused with medium containing ATP, no carbon fixation was detected in 1 mol m -3 total dissolved inorganic carbon (TDIC) at pH 8·5. By increasing TDIC to 10 mol m-3, dark fixation became detectable, although it was still lower than that of intact cells at 1mol m-3 TDIC. Addition of PEP or PEP and PEP carboxylase to the perfusion media significantly increased the dark-carbon fixation. Perfusion with vanadate had no effect on the dark-carbon fixation.

Notes: Phosphate uptake in the freshwater charophyte plant Chara corallina was found to be strongly dependent on the presence of Na in the external medium. Based on the reciprocal stimulations of 32Pi uptake by Na and 22Na uptake by Pi, the logical mechanism for Pi uptake appears to be a nNa/Pi symport with a half-maximal stimulation (Km) for Na of approximately 300 μM and a Km for Pi of approximately 10 μM. Comparison of the stimulations of 32Pi and 22Na influxes at pH 6 gives a stoichiometry of Na : Pi of 5·68. The reduction in Pi influx with increasing pH is consistent with the transported species being the monovalent H2PO4−. In voltage-clamp experiments, currents elicited by Pi in the presence of Na were equivalent to an influx of positive charge which exceeded the measured influxes of 32P by a factor of 6·26. Intracellular perfusion was used to examine the dependence of Pi influx on ATP and Na. In perfused cells, Pi influx was low when ATP was absent from the internal medium or Na was absent from the external medium. Addition of ATP alone had little effect whereas addition of Na alone increased the 32Pi influx slightly. Addition of both ATP and Na together restored Pi influx to rates comparable to those of intact cells. It is suggested that the ATP is required for membrane hyperpolarization which in turn drives the highly electrogenic flux of Pi with up to 6 Na. However, consideration of the electrochemical potential differences for Na and Pi at pH less than 6 shows that nNa/Pi would not be feasible. It is suggested that at low pH, H+ may substitute for Na.

Notes: A suspension-cultured cell strain of the mangrove plant (Bruguiera sexangula) was established from a callus culture and maintained in an amino acid medium in the absence of NaCl. NaCl non-adapted cells were transferred to media containing 0–200 mm NaCl. The initial growth rate decreased gradually with increasing salt concentrations. However, at up to 150 mm NaCl, cell number growth at the highest point was almost the same as that at lower salt concentrations. Cells even continued to grow in the presence of 200 mm NaCl.Cells incubated in a medium containing 50 mm NaCl for 3 weeks accumulated Na+, while those incubated in 150 mm NaCl for 2 d showed only a transient increase in Na+ and Cl– concentrations. In the latter treatment, the intracellular concentration of Na+ returned to the original low level within 2 weeks. It took a longer time for Cl– to return to its original level. As a result, the Na+ and Cl– concentrations in cells cultured with 50 mm NaCl were much larger than those in cells cultured with 150 mm NaCl. The intracellular distribution of ions after transfer to the medium containing 150 mm NaCl was analysed by isolating the vacuoles.Treatment with amiloride, an inhibitor of the Na+/H+ antiporter, suppressed the recovery of Na+ to the original level in the cells. Treatment with 150 mm NaCl for 3 d stimulated the activities of both the vanadate-dependent H+-ATPase and the Na+/H+ antiporter in the plasma membrane fraction.

Notes: Solid cell nests of the thyroid gland were studied in 44 patients with medullary thyroid carcinoma. In 10 (22.7%) patients, solid cell nests were revealed in the vicinity of tumour foci (five cases) or in the contralateral thyroid lobe and isthmus (four cases); in one case the location was indeterminate. In all seven cases in which immunohistochemical studies were carried out, solid cell nests showed negative staining for thyroglobulin, calcitonin and chromogranin A, findings which were distinct from those in medullary thyroid carcinoma. It is therefore suggested that solid cell nests of the thyroid are not precursors of this tumour.

Notes: Preliminary data suggest that short-term antibiotic therapy with a single drug is effective for the treatment of patients with pouchitis. However, some patients are resistant to treatment.〈section xml:id="abs1-2"〉〈title type="main"〉Aim:To evaluate the therapeutic efficacy of a prolonged course of a combination of two antibiotics in patients with refractory or recurrent pouchitis, as well as its impact on their quality of life.〈section xml:id="abs1-3"〉〈title type="main"〉Methods:Patients with active refractory or recurrent pouchitis were recruited. This was defined as both: (i) a history of pouchitis at least twice in the last 12 months or persistent pouchitis requiring continual intake of antibiotics; and (ii) a Pouchitis Disease Activity Index score 3 7 (best to worst pouchitis=0–18) at the beginning of therapy. Treatment consisted of a combination of metronidazole, 400 or 500 mg twice daily, and ciprofloxacin, 500 mg twice daily, for 28 days. Symptomatic, endoscopic and histological evaluations were undertaken before and after antibiotic therapy using the Pouchitis Disease Activity Index score. Remission was defined as a combination of a Pouchitis Disease Activity Index clinical score of 〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:02692813:APT1203:les" location="les.gif"/〉 2, endoscopic score of 〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:02692813:APT1203:les" location="les.gif"/〉 1 and total score of 〈inlineGraphic alt="leqslant R: less-than-or-eq, slant" extraInfo="nonStandardEntity" href="urn:x-wiley:02692813:APT1203:les" location="les.gif"/〉 4. The quality of life was assessed with the Inflammatory Bowel Disease Questionnaire, which encompasses bowel, systemic and emotional symptoms as well as social function (worst to best=32–224).〈section xml:id="abs1-4"〉〈title type="main"〉Results:Forty-four patients (24 male, 20 female; median age, 37.5 years) entered the trial and completed treatment. Thirty-six (82%) went into remission. The median Pouchitis Disease Activity Index scores before and after therapy were 12 (range, 8–17) and 3 (range, 1–10), respectively (P 〈 0.0001). The median Inflammatory Bowel Disease Questionnaire score also significantly improved from 96.5 (range, 74–183) to 175 (range, 76–215) with this therapy (P 〈 0.0001). The eight patients (five male, three female) who did not go into remission were significantly older (median 47.5 vs. 35 years; P=0.007), had a longer history of pouchitis (95.5 vs. 26 months; P=0.0008), had a greater proportion with chronic pouchitis (chronic/relapsing: 6/2 vs. 9/27; relative risk, 1.6; 95% confidence interval, 1.0–2.4) and tended to have a higher Pouchitis Disease Activity Index score before treatment (median 14.5 vs. 12; P=0.13) than those who went into remission. Even in these eight patients, the median Pouchitis Disease Activity Index score significantly improved from 14.5 (range, 8–16) to 9.5 (range, 7–10) (P=0.0078), as did the Inflammatory Bowel Disease Questionnaire score from 95.5 (range, 74–134) to 127 (range, 76–187) (P=0.039). The Inflammatory Bowel Disease Questionnaire score strongly correlated with the Pouchitis Disease Activity Index score (r=0.79, P 〈 0.0001), and was significantly related to the patients' overall assessment of satisfaction (P 〈 0.0001). No serious side-effects were noted.〈section xml:id="abs1-5"〉〈title type="main"〉Conclusions:Four-week treatment with a combination of metronidazole and ciprofloxacin is highly effective in patients with active recurrent or refractory pouchitis, objectively improving the inflammation and quality of life. The Inflammatory Bowel Disease Questionnaire is a sensitive tool for evaluating patients with pouchitis, and correlates well with disease activity.