Bran is an effective treatment for constipation but its use is often limited by heartburn and bloating. This study examined the effect of fine and coarse bran (15 g) on the gastric emptying and small bowel transit of a 325 kcal rice test meal. Twelve healthy volunteers underwent a three way cross over study, ingesting the technetium-99m labelled rice meal with or without 15 g of indium-l1lm labelled fine or coarse bran, in random order. Serial scintigraphic images were obtained to define gastric emptying and colonic arrival of label. Compared with control values (99 (9) minutes) (mean (SEM)), the time to 50% gastric emptying was significantly delayed by coarse but not fine bran, being 121 (6) and 104 (9) minutes respectively, p<0 05, n=12. Fundal emptying was unchanged but both brans seemed to increase the proportion of isotope in the antrum at 90 minutes. Small bowel transit was slightly faster with both bran types but in this study the difference was not significant. Both the bran and rice labels moved down the gut without significant separation. Fine bran causes less disturbance of gastric physiology than coarse bran.

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The first observations of oxidation of palladium(II) by water are reported. The pallada(II)cyclic complex ion [Pd(CH2CH2CH2CH2){(pz)3BH}]- [(pz)3BH = tris (pyrazol-1-yl)borate)] is oxidized by water in acetone or tetrahydrofuran to form Pd(CH2CH2CH2CH2)(OH){(pz)3BH} and hydrogen, and oxidation by hydrogen peroxide gives the same complex. Oxidation by halogens results in the formation of Pd(CH2CH2CH2CH2)(X){(pz)3BH} (X = Cl, Br, I), and these complexes, together with the hydroxopalladium(IV) complex, represent the first examples of stable dihydrocarbylpalladium(IV) complexes. The octahedral complex Pd(CH2CH2CH2CH2)(OH){(pz)3BH} forms adducts with phenol, 3-methylphenol, and pentafluorophenol with an overall composition of Pd(CH2CH2CH2CH2)(OH){(pz)3BH}·2ArOH (5 and 6) and Pd(CH2CH2CH2CH2)(OH){(pz)3BH}·C6F5OH (7). Complex hydrogen-bonding interactions occur in the adducts, consistent with the assignment of the phenol and 3-methylphenol adducts as hydroxopalladium(IV) complexes and the pentafluorophenol adduct as an aquapalladium(IV) complex. Complexes 5 and 6 are considered to contain the hydrogen-bonding motifs H−O(Pd)···HO(Ph)···HOPh and Ar(H)O···H−O(Pd)···HOAr, respectively, and 7 to contain an aquapalladium(IV) cation in which both hydrogen atoms of the aqua ligand act as hydrogen-bond donors to pentafluorophenoxide ions in a centrosymmetric dimer, [Pd(CH2CH2CH2CH2)(OH2){(pz)3BH}·C6F5O]2. The complex ions [PdMeR{(pz)3BH}]- (R = Me, Ph) react with water or halogens to form the PdMe2R{(pz)3BH} and PdIIR species, and in the case of water as the oxidant, hydrogen is also formed. These reactions occur via initial oxidation to form undetected palladium(IV) species, presumably PdMeR(X){(pz)3BH} (X = OH, Cl, Br, I), which undergo rapid methyl group exchange reactions with [PdMeR{(pz)3BH}]- to form PdIIR species and PdMe2R{(pz)3BH}. The oxidation of palladium(II) by water and the structural analysis of hydroxo- and aquapalladium(IV) complexes represent the first examples of organopalladium(IV) chemistry in aqueous media.