Phosphorus deficiency in Lupinus albus. Altered lateral root development and enhanced expression of phosphoenolpyruvate carboxylase.

The development of clustered tertiary lateral roots (proteoid roots) and the expression of phosphoenolpyruvate carboxylase (PEPC, EC 4.1.1.31) in roots were studied in white lupin (Lupinus albus L.) grown with either 1 mM P (+P-treated) or without P (-P-treated). The +P-treated plants initiated fewer clustered tertiary meristems and the emergence of these meristems was delayed compared with - P-treated plants. Proteoid root zones could be identified 9 d after emergence in both P treatments. Amounts of PEPC mRNA, PEPC specific activity, and enzyme protein were greater in proteoid roots than in normal roots beginning at 10, 12, and 14 d after emergence, respectively. The increases in PEPC mRNA, PEPC enzyme, and PEPC specific activity suggest that this enzyme is in part under transcriptional regulation. Recovery of organic acids from root exudates coincided with the increases in PEPC specific activity. The -P-treated plants exuded 40-, 20-, and 5-fold more citrate, malate, and succinate, respectively, than did +P-treated plants. Data presented support the hypothesis that white lupin has concerted regulation of proteoid root development, transcriptional regulation of PEPC, and biosynthesis of organic acids for exudation in response to P deficiency.

Multipolypoid intussusceptum: a distinctive appearance of ileoileocolic intussusception at the ileocecal valve.

Objective. To determine whether ileoileocolic intussusception can be diagnosed by a distinctive appearance during pneumatic reduction. Materials and methods. We reviewed the clinical, pathologic, and imaging findings of 11 patients with ileoileocolic intussusceptions seen in our hospital between January 1989 and July 1994. The patients ranged in age from 4 months to 4 years and 2 months. We specifically evaluated the appearance of these intussusceptions on air enemas performed in nine of these patients. Another 22 air enemas of all patients with surgically proven ileocolic intussusception seen during the same time period were also reviewed for comparison. Results. In seven of the nine patients with ileoileocolic intussusception who had air enemas, the intussusceptum clearly had two or more separate polypoid components once it was reduced to the cecum. This distinctive appearance was not seen until the intussusceptum was tethered at the ileocecal valve. The intussusceptum was also reduced to the cecum in 19 patients from the control group with ileocolic intussusception. In contrast to the ileoileocolic intussusceptums, these intussusceptums were either smoothly marginated (16 patients) or slightly lobular (three patients). Conclusion. In most patients with ileoileocolic intussusception, the intussusceptum has two or more polypoid components at the level of the ileocecal valve which are easily distinguished from the smoothly marginated or slightly lobular intussusceptum seen with ileocolic intussusception.

Ileocolic intussusception: extensive reflux of air preceding pneumatic reduction.

The use of an air enema for diagnosis and treatment of intussusception has recently gained popularity. The current end point for reduction is the reflux of air into the terminal ileum. The authors report three cases in which air freely refluxed into the terminal ileum without complete reduction of the intussusceptum. Thus, reflux of air alone cannot be relied on as the sole criterion for reduction. Close examination of the cecum for a persistent filling defect is imperative to exclude unsuccessful reduction.