Lack of effect of spearmint on lower oesophageal sphincter function and acid reflux in healthy volunteers

BACKGROUND: Spearmint is commonly used as an antispasmodic and as a flavouring in several medications including antacids. It can produce heartburn, presumably by lowering lower oesophageal sphincter (LES) tone, but the mechanism has not previously been objectively examined. AIM: To study the effect of spearmint on LES function, acid reflux and symptoms. METHODS: In healthy volunteers, a Dent Sleeve and a pH electrode were placed in the distal oesophagus. They were then given spearmint either in a flavouring (0.5 mg), or a high (500 mg) dose, or a placebo, using a double-blind randomized crossover design. LES pressure, oesophageal pH and symptoms were recorded for 30 min before and after administration. RESULTS: LES pressure was not affected by spearmint, either high dose (19.6 vs. 16.0 mmHg), flavouring dose (20.2 vs. 19.8 mmHg) or placebo (20.5 vs. 19.2 mmHg, all N.S.). There were no differences in reflux occurrence following high dose (mean = 0.65 vs. 0.85 episodes), low dose (0.4 vs. 0.5 episodes) or placebo (0.7 vs. 1.10 episodes, all N.S.). There was a significant increase in mean symptom scores following high-dose spearmint (0 vs. 0.35, P = 0.03), but not low dose (0 vs. 0.2) or placebo (0 vs. 0.5, both N.S.). One subject reported symptoms with placebo, one with low dose, and six with high dose; all without increased reflux episodes or decreased sphincter pressure. CONCLUSION: Spearmint has no effect on LES pressure or acid reflux. Flavouring doses of spearmint do not produce more symptoms than placebo while high doses can be associated with symptoms, presumably from direct mucosal irritation but not reflux.     

Visceral hyperalgesia and intestinal dysmotility in a mouse model of postinfective gut dysfunction

BACKGROUND & AIMS: We established the concept that transient enteric infection may lead to persistent gut dysfunction, evident in vitro, in nematode-infected mice. The present study determined whether gut dysfunction in this model involves motor and sensory changes reminiscent of changes found in patients with postinfective irritable bowel syndrome (PI-IBS) and investigated underlying mechanisms. METHODS: Mice infected up to 70 days previously with Trichinella spiralis (Tsp) underwent videofluoroscopy with image analysis to assess upper gastrointestinal motility. Pseudoaffective responses to colorectal distention (CRD) were assessed using a barostat and validated by single fiber recordings from spinal nerves during CRD. Tissues were examined at different time points for histology, immunohistochemistry, and cytokine analysis. Some mice received dexamethasone intraperitoneally on days 23-25 PI or Tsp antigen orally on days 29, 43, and 57 PI. RESULTS: From day 28 PI, no discernible inflammation was present in the gut. Frequency and propagation velocity of intestinal contractions decreased, and retroperistalsis increased at days 28 to 42 PI. CRD induced an allodynic and hyperalgesic response in PI mice, which was accompanied by increased single unit discharge. Gavage of Tsp antigen induced T-cell responses and sustained gut dysfunction for 70 days PI. Administration of dexamethasone postinfection normalized dysmotility and visceral hyperalgesia. CONCLUSIONS: Long-lasting gut dysmotility and hyperalgesia develop in mice after transient intestinal inflammation. These changes are maintained by luminal exposure to antigen and reversed by corticosteroid treatment. The findings prompt consideration of this as a model of PI-IBS.     

Effect of acupuncture on gastric acid secretion in healthy male volunteers

Six randomized, placebo controlled studies were performed to investigate the effect of electroacupuncture on gastric acid output in 38 healthy males. Electroacupuncture decreased basal acid output when compared to placebo acupuncture [from 3.50±0.59 mmol/hr to 2.54±0.56 mmol/hr (P<0.05)] as well as sham feeding-stimulated acid output [from 18.52±2.25 mmol/hr to 5.38±2.11 mmol/hr (P<0.005)], but had no effect on the pentagastrin stimulated acid output. The inhibitory effect of acupuncture on sham feeding-stimulated acid output was not affected by local anesthesia of the acupoint, but was prevented by a prior intravenous naloxone injection. Acupuncture did not alter plasma gastrin levels (20.7±7.6 g/liter, vs control 21.2±7.2 g/liter) but naloxone increased it (26.1±14.5 g/liter) (P<0.05). We conclude that the antisecretory effects of electroacupuncture do not result from decreased gastrin release or decreased parietal cell sensitivity to gastrin, but are mediated through naloxone-sensitive opioid neural pathways and vagal efferent pathways.Dr. Tougas was supported by a Fellowship of the Medical Research Council of Canada.This work was presented in part at the Annual Meeting of The American Gastroenterological Association, New Orleans, May 1988; Washington, May 1989; and San Antonio, May 1990.     

Development of a systematic observation protocol of physical exposure of the back: a preliminary study

OBJECTIVE: At present there is no systematic observation protocol for the assessment of the multi-factorial aspects of physical exposure related to the back used within the constraints of occupational epidemiological research. In this context, a new preliminary systematic observation protocol is proposed to assess exposure to physical loading of the back using nine categories of physical risk factors: the SOPE back protocol. The objective of this study was to investigate whether the new protocol can correctly identify the level of exposure related to measured physical loading of the back. METHODS: The subjects of this closed cohort study were 451 manual workers at a natural gas distribution company. The assessment of exposure was made with the protocol using groups with different job titles. The workers were followed for a 2 yr period to establish the risk of a new occurrence of complete disability related to the back (NOCD back injury) in each job grouping. RESULTS: Based on the median of the total scores derived from the protocol, two levels of exposure were identified (high and low). CONCLUSION: Taking into account the limitations of this study, the protocol in development may be a good tool to establish two levels of exposure to physical loading of the back in large epidemiological studies of occupational low back pain. Further research is needed to replicate these results with larger samples and to test the reliability and predictive validity of the protocol.     

Long-term efficacy of Botulinum toxin in classical achalasia: a prospective study

OBJECTIVE: We sought to examine the long-term efficacy of intrasphincteric Botulinum toxin A injection in a prospective cohort study of 30 patients with achalasia. METHODS: Thirty patients with classical achalasia were treated with intrasphincteric Botulinum toxin A injection. Follow-up consisted of clinical assessment, symptom scoring, and postinjection manometry. RESULTS: Symptomatic improvement for >3 months was seen in 23 of 30 patients (77%). Of the 23 initial responders, seven (30%) experienced a sustained symptomatic response after a single Botulinum toxin injection (mean follow-up, 21 months). The remaining 16 initial responders (70%) eventually relapsed (mean initial response, 11 months). Nine received a 2nd Botulinum toxin injection, and seven experienced an ongoing response (mean duration, 9 months); two patients eventually required a 3rd injection with good effect (mean duration, 22 months). The remaining seven patients who relapsed after Botulinum toxin opted for pneumatic dilation or surgical myotomy. Five of the seven patients who had no initial response received a 2nd injection but again did not respond. A residual lower esophageal sphincter pressure <18 mm Hg after the first Botulinum toxin injection predicted a good response to Botulinum therapy (single or multiple injections, p < 0.002, positive predictive value = 0.71, negative predictive value = 1.0). Neither initial nor sustained response to Botulinum toxin could be predicted based on gender, age, duration of illness, previous pneumatic dilation, or esophageal motility before treatment. CONCLUSIONS: We found that 77% of patients with classical achalasia experienced a good symptomatic response after Botulinum toxin and 30% of initial responders achieve sustained symptomatic relief after a single treatment with Botulinum toxin. The initial responders who relapsed did well with subsequent Botulinum toxin A. Lack of an initial symptomatic response and residual lower esophageal sphincter pressure > or =18 mm Hg after Botulinum toxin are associated with a poor response.