Search

June 8-11, 2014; International audience; Two low-cost methods, sputtering deposition and sol–gel processes, were used to study the effects of bottom electrodes preparation on the microstructure evolution and texture development of oriented PZT films. Microstructure development and perovskite content are strongly dependent on the temperature deposition of the Pt bottom electrode on SOI substrate and on the post-deposition annealing heating rate. Fast heating rate forms a dense fine-grained microstructure with polycristalline orientation. Very slow heating rate leads to (001) orientations.The texture selection of PZT films is independent of deposition process but sensitive to the Pt bottom electrode temperature deposition. Correlation and comparison of oriented sol–gel and sputtered PZT films with electrical properties are also made.

Maroc Médical, Vol. 28, No 2 (2006)

Miniature pigs were chronically implanted with gastric electrodes, strain gauge devices allowing the measurement of circular contractions in the antrum and body of the stomach, and with a duodenal catheter through which duodenal infusions were administered. Inhibition of gastric motility by intraduodenal agents was measured before and after truncal vagotomy in conscious animals 20 min after feeding of a normal meal. The agents infused in the duodenum (10 ml/min, 4 min), were: HCl 75 mEq/l(A), glucose 100 g/l(G), olive oil 10% pH 7(L), amino acids (AA) and saline. Before vagotomy, motor activity during the first 5 min was inhibited 50-80% with respect to basal levels; the duration of action was G No. L greater than A; AA had very little effect, and saline no effect. Inhibition was on the whole similar in the antrum and gastric body. After vagotomy, the inhibitory effect of A was reduced from 80 to 20% in the antrum, and completely suppressed in the gastric body. Inhibitory effects of G and L were completely suppressed.

Male Wistar rats, fed a standard normal laboratory diet, drank ad libitum a 20% ethanol solution for 3 months. Basal and 2-deoxy- D -glucose (2DG) stimulated pancre

134 patients with radiolucent gallstones were randomly allocated to receive either placebo or 1 of 3 different doses of chenodeoxycholic acid (CDCA); 750, 1,500, or 3,000 mg). The initial dose was lowered if not well tolerated. 107 patients were treated for more than 3 months. Among them, stones dissolved in 21 and were smaller in 25 patients. Partial or complete dissolution occurred in 4 of the 13 receiving 375 mg/day, 14 of 37 receiving 750 mg, 24 of the 38 receiving 1,500 mg and 4 of 8 receiving 3 000 mg/day. The number of responders to the therapy was significantly greater in the groups of patients receiving 1,500 mg/day or 17–24 mg/kg body weight than in any other group. However, side effects, i.e., diarrhea and transaminase increase, are also dose related. It appears from this study that the optimal dose of CDCA may be between 17 and 20 mg/kg body weight.

Gastric myoelectrical and mechanical activity was recorded in miniature pigs using chronically implanted electrodes and strain gauge force transducers. Semiautomated methods were devised to obtain quantitative evaluations of the electrical and mechanical parameters measured in fasted and fed animals. The patterns of gastric myoelectrical activity in pigs were, on the whole, similar to the patterns described in dogs, including regular cyclic control activity and spike response activity associated with muscle contraction. However, several points were peculiar to the species studied: conduction velocity of pacesetter potentials increased only moderately in the antrum; tachygastria never occurred in the experiments; in response to a standard meal, the frequency of pacesetter potentials gradually increased; mechanical activity proceeded at its maximal force immediately after feeding and for a long period; no evidence of 'migrating electrical complexes' was found in the stomach during fasting. The 40-min period following administration of a test meal appeared especially suitable for pharmacological or physiological experiments in which inhibitory factors are to be tested on the stomach.

Biliary secretion was studied in normolipedemic rats after a 7 day treatment with the hypolipidemic drugs, tiadenol (bis-(hydroxyethylthio)-1,10-decane), clofibrate and clofibride (chloro-4-phenoxy-2-methyl-2-propionate of dimethylcarbamoyl-3-propyl). All three drugs decreased blood cholesterol and total lipids, increased liver weight and liver catalase content, and decreased biliary excretion of cholesterol. The biliary concentrations of bile salts, phoslipids and cholesterol decreased to a variable extent, in such a way that ratio of bile salts + phospholipids to chloresterol was increased by the drugs. The bile salt independent fraction was increased. The effects were qualitatively similar for all three drugs tested, but quantitative differences appeared for some of the parameters.

A method of recording the electromyogram of the pelvic colon in man is described. The use of a metallic "mucosal" electrode permits recordings to be made without an abdominal incision. Results obtained in man are compared to recordings made in animals, using an electrode placed directly against the muscular layer after laparotomy. In man, as in the rabbit, two types of electrical activity were recorded: slow, regular variations, and bursts of spikes. The slow waves appear in sequences, lasting no more than 5 to 20% of the total recording time. In man, some correlation is found between slow waves and bursts of spikes. These spikes are often observed independently of intraluminal pressure changes.

The effects of somatostatin on the secretions of the exocrine pancreas were studied in anesthetized and conscious fistula rats. Somatostatin resulted in a dose-dependent decrease of basal secretion (flow, bicarbonate, protein) in conscious rats. In anesthetized rats, basal secretion was initially augmented by bolus injections of 10 to 50 microgram per kg and was subsequently decreased by venous infusions of somatostatin at 1.5 to 100 microgram.kg-1.hr-1. This inhibition, which was poorly dose dependent, was greater for protein secretion than for that of water and electrolytes. Somatostatin inhibited caerulein-stimulated protein secretion by 40 to 50% but had no effect on secretion stimulated by exogenous and endogenous secretin. Somatostatin markedly inhibited secretion stimulated by 2-deoxyglucose and by electrical stimulation of the vagus nerves in a dose-dependent fashion (protein and bicarbonate exhibited a maximal inhibition of 85%). Acetylcholine-stimulated secretion was also inhibited by somatostatin, but the maximal inhibitions observed were only 505 for protein and 60% for bicarbonate. These findings agree with the hypothesis that somatostatin infusion leads to both a decrease of acetylcholine release at nerve endings and to a direct inhibition at the level of pancreatic effector cells.

Thyrocalcitonin (TCT) is known to decrease gastric secretion in man through a mechanism involving probably both a direct effect on the secretory cells and an inhibition of gastrin release. Pentagastrin (PG) increases the pressure in the lower oesophageal sphincter (LES). These experiments were devised to investigate a possible antagonism between TCT and PG on the LES pressure (LESP).

A diet containing citrates increased bile salts and phospholipids concentration in the rats' bile, while a diet containing a hypolipemic factor (tiadenol) decreased cholesterol. No potentiation was obtained when the diet contained both factors.

The effects on bile secretion of classical stimulants and depressants of the parasympathic system were reinvestigated in the anaesthetized rat. Antimuscarinic drugs and vagotomy did not decrease bile

The period of the pacesetter potentials (PP) in the normal human stomach was studied when infusing HCl (75 mEq/l) or saline in the stomach or duodenum. When a 350-ml volume of saline was infused into the stomach, an 11 % increase of the PP period was observed. With 350 ml of acid solution, the maximum increase was 40%. This occurred 8 min after the onset of infusion, at the moment when the serum gastrin level was significantly lowered. When the acid solution was infused into the duodenum, a flow rate of acid dependent increase of the PP period occurred (43% with 4 ml/min). Saline induced no change. A single intravenous injection of secretin (0.5 U/kg) induced an increase in the PP period whose maximum (35%) occurred 4 min after the injection. The results suggest that gastric myoelectrical activity may be affected by a hormonal regulation in which endogenous secretin and gastrin would determine opposite responses.