Objective To ascertain whether metronidazole treatment of women with a heavy growth of Gardnerella Design A multicentre, randomised, placebo-controlled trial Setting Four metropolitan hospitals.Participants Eight hundred and seventy-nine singleton women with a heavy growth of G. vaginalis or Interventions Oral metronidazole (400 mg) or placebo twice daily for two days at 24 weeks of gestation, Main outcome measures Spontaneous preterm birth less than 37 weeks.Results Intention-to-treat analysis showed no difference between metronidazole and placebo groups in overall preterm birth (3 1

1. Balloon distension of the duodenum 2 cm oral or anal to the sphincter of Oddi-duodenal junction elevated the amplitude of spontaneous sphincter of Oddi phasic contractions by 37-7 + 8-5 or 120-1 + 79-8%, respectively (mean + S.E.M., both n= 6, P< 0 05, Wilcoxon test). To further investigate this response, this study aimed to determine if: (i) electrical field stimulation (EFS) of the duodenum influences sphincter of Oddi activity; (ii) intramural nerves mediate the response; and (iii) nicotinic and/or muscarinic receptors are involved. 2. Electrical field stimulation (70 V, 0 5 ms; 5-60 Hz, 10-20 s) of the duodenal anterior serosal surface 2-4 cm oral or anal to the sphincter of Oddi-duodenal junction, produced excitatory responses in the sphincter of Oddi in anaesthetized Australian brush-tailed possums (n = 45). 3. These responses were frequency dependent, maximal at 30 Hz (n = 4) and abolished by tetrodotoxin (9 jug kg-' I.A.; n = 6), or by crushing the duodenum (n = 3). Hexamethonium bromide (30 mg kg-' i.v.) did not significantly alter the response to duodenal EFS either oral (n =6) or anal (n =8) to the sphincter of Oddi-duodenal junction. Atropine sulphate (30 jug kg-' i.v.) reduced the response to duodenal EFS oral and anal to the sphincter of Oddi-duodenal junction to 11P2 + 5-8 (n = 6) and 45 0 + 26-8% (n = 8), respectively (both P< 0 05).4. Bilateral cervical vagotomy and guanethidine infusion (10 mg kg-' over 15 min i.v.) did not significantly alter the responses to duodenal EFS (n = 7). 5. Excitatory intramural neural pathways between the sphincter of Oddi and the segment of duodenum 4 cm oral and anal to the sphincter of Oddi-duodenal junction have been demonstrated. These postganglionic pathways may involve muscarinic receptors.

Two models of transsphincteric flow and a model evaluating pumping activity were established in the anesthetized Australian brush-tailed possum to determine whether the sphincter of Oddi (SO) acts as a resistor or as a pump. A simple model of transsphincteric flow (inflow only) demonstrated that at physiological common bile duct (CBD) pressure, 9.5 +/- 0.3 cmH2O (n = 7), transsphincteric flow occurred between SO pressure waves (n = 10). A second more complex transsphincteric flow model was established that permitted simultaneous measurements of inflow, outflow, CBD pressure, SO basal pressure, SO contraction frequency, and amplitude. At physiological CBD pressure, inflow always equaled outflow (157.0 +/- 11.2 and 156.4 +/- 11.4 microliters/min, respectively; n = 7). The SO displayed regular contractions superimposed on a basal pressure of 1.1 +/- 0.4 mmHg. Contraction amplitude was 12.6 +/- 3.0 mmHg and the frequency was 3.6 +/- 0.4 contractions/min (n = 7). Pressure waves recorded in the CBD corresponded to the SO contractions and reflected SO activity. Transsphincteric flow occurred between SO contractions and was obstructed by these contractions. Stimulation of SO activity (basal pressure and contraction frequency) with intra-arterial injections of motilin (200 ng/kg) or erythromycin (200 micrograms/kg) abolished transsphincteric flow. Reduction in SO contraction frequency to 72.7 +/- 7.2% (P < 0.01, paired t test) after administration of Cisapride (2 mg/kg iv) increased transsphincteric flow to 147.6 +/- 12.3% (n = 7, P < 0.05, paired t test). In six possums, possible SO pumping action was evaluated. A manometer was connected to the CBD, and a second manometer was connected to the duodenum surrounding the papilla.(ABSTRACT TRUNCATED AT 250 WORDS)

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