Poly[dimethyldiphenylphosphonium [di-mu4-iodido-tetra-mu3-iodido-pentacopper(I)]].

The title compound, {(C(14)H(16)P)[Cu(5)I(6)]}(n), prepared from the reaction between copper powder, iodine and dimethyldiphenylphosphonium iodide in hydroxyacetone, features an anion that consists of a continuous two-dimensional Cu-I sheet [Cu-I = 2.5960 (14)-2.6994 (13) A and Cu-I-Cu = 63.28 (5)-114.25 (5) degrees]. The cation, which lies on a mirror plane, is a typical dimethyldiphenylphosphonium ion. The structure shows a strong tendency towards segregation of the inorganic and organic parts of the structure into separate subspaces. The two-dimensional Cu-I sheet displays a pronounced subcell with pseudo-tetragonal symmetry that is broken by ordered vacancies on the Cu position. The symmetry is further reduced by the orientation of the interleaved organic counter-ion that is inclined with respect to the pseudo-mirror planes defined by the Cu-I sheet normal, perpendicular to the b axis.

Bis(tetra-phenyl-phospho-nium) tetra-iodidomanganate(II) acetone monosolvate.

The title compound, (C(24)H(20)P)(2)[MnI(4)]·(CH(3))(2)CO, prepared from the reaction of manganese powder, iodine and tetra-phenyl-phospho-nium iodide in acetone shows a tetra-hedral complex anion [Mn-I = 2.6868 (5)-2.7281 (4) Šand I-Mn-I = 104.011 (13)-116.164 (15)°], two tetra-phenyl-phospho-nium cations and one mol-ecule of acetone.

Bis(tetra-propyl-ammonium) di-µ(3)-iodido-di-µ(2)-iodido-diiodidodi-pyridine-tetra-copper(I).

The title compound, (C(12)H(28)N)(2)[Cu(3.194)I(6)(C(5)H(5)N)(2)] was prepared from reaction of copper powder, copper(I) oxide, hydro-iodic acid, tetra-propyl-ammonium iodide and pyridine under hydro-thermal conditions. In the centrosymmetric Cu(4)I(6) (2-) anion, one Cu site is in a trigonal-planar coordination while the second Cu site, which is only partially occupied [site occupancy of 0.5968 (16)], is surroundedby three iodine atoms and one pyridine molecule in a distorted tetrahedral coordination.

Bis(isopropyl-triphenyl-phospho-nium) di-µ-iodido-bis-[iodidocopper(I)].

The title compound, (C(21)H(22)P)(2)[Cu(2)I(4)], prepared from reaction between copper powder, iodine and isopropyl triphenyl-phospho-nium iodide in hydroxy-acetone (acetol), shows an already known Cu(2)I(4) (2-) anion with a planar conformation [Cu-I range = 2.5108 (3)-2.5844 (3) Šand I-Cu-I range = 110.821 (10)-125.401 (10)°].

Parametric study of neural gastric electrical stimulation in acute canine models.

Manipulation of gastric motility by gastric electrical stimulation (GES) has been suggested as a minimally invasive alternative treatment of gastric motility disorders and obesity. However, only neural GES (NGES) has been successful in invoking gastric contractions. Nevertheless, the relationship between these contractions and the controlling NGES parameters has not been quantified. We aimed at determining the relationship between the electrical energy delivered to the tissue as a function of NGES parameters, and the strength and duration of the resulting invoked gastric contractions. Five healthy mongrel dogs underwent subserosal prepyloric implantation of two NGES electrode pairs. Gastric motility was captured by a force transducer implanted in the vicinity of the distal pair of stimulating electrodes. Custom-designed implantable stimulator delivered NGES with 8-16 V (peak-to-peak) amplitudes, and 60-100% duty cycles. Normalized motility index (MI) was utilized to quantify the contractions recorded from the force transducer. The MI increased with increasing voltage amplitudes. However, it remained remarkably constant across all duty cycles when voltage was held constant. Calculated motility generation efficiency indices (MGEI) indicated that highest energy efficiency for invoked motility was achieved at the lowest duty cycle. The parametric data obtained in the present study can be utilized to optimize the power efficiency of implantable gastric neurostimulators.

Implantable neural electrical stimulator for external control of gastrointestinal motility.

Functional electrical stimulation has been suggested as a possible avenue for treating a variety of gastrointestinal motility-related disorders such as gastroparesis, chronic constipation and morbid obesity. The aims of the present study were to design a radio-frequency controlled multi-channel implantable neural gastrointestinal electrical stimulator and test it in an acute canine model. The stimulation parameters can be reprogrammed after implantation, allowing the execution of parametric studies and the investigation of their efficacy in producing controlled gastrointestinal contractions. Bipolar pulse trains of 50Hz frequency, 8-16V(pp) amplitude, 10-100% duty cycle, 1-120s duration, and 2s to 1h pause between successive stimulation sessions were delivered to the stomachs of nine dogs. The resulting contractions were measured by force transducers and digitally recorded on a personal computer. The acute studies confirmed the effectiveness of electrical stimulation in producing invoked gastric contractile activity under the control of the implantable neurostimulator.

Pre-pyloric neural electrical stimulation produces cholinergically-mediated reverse peristalsis in the acute canine model of microprocessor-invoked gastric motility for the treatment of obesity.

BACKGROUND: Gastric Electrical Stimulation (GES) has been suggested as a new tool for the treatment of obesity. Among the known methods for GES, only Neural Gastric Electrical Stimulation (NGES) provides direct control of contractility without utilizing the spontaneously existing gastric electrical activity as an intermediary. However, only one of the established GES techniques, gastric pacing, has been described to produce retrograde peristalsis for delaying gastric emptying. The aim of this study was to explore the possibility of producing retrograde peristalsis using either single electrode set or dual electrode set NGES. METHODS: 8 anesthetized dogs underwent laparotomy and implantation of 2 circumferential electrode sets approximately 3 cm and 7 cm proximal to the pylorus, respectively. Single-set and dual-set NGES sessions were repeatedly administered using a custom-designed implantable neurostimulator. Gastric motility patterns were captured using 3 force transducers implanted on the anterior gastric wall along the gastric axis. Motility indices and velocities were employed to quantify the produced contractile patterns. RESULTS: Both single-set and dual-set NGES produced circumferential lumen-occluding contractions in the vicinity of the electrode sets. The invoked contractions propagated proximally in a retrograde fashion. The propagation scope was different depending on the number of electrode sets used. Different velocities of the invoked retrograde contractions associated with single- and dual-set NGES were observed and quantified. Contractility patterns reflected by the normalized motility indices were very similar regardless of the electrode stimulation technique. CONCLUSION: Pre-pyloric NGES can produce controlled retrograde peristalsis and serve as another avenue for the treatment of obesity.