Effects of acetorphan, an enkephalinase inhibitor, on experimental and acute diarrhoea.

Acetorphan is an orally active inhibitor of enkephalinase (EC 3.4.24.11) with antidiarrhoeal activity in rodents apparently through protection of endogenous enkephalins and a purely antisecretory mechanism. Its antidiarrhoeal activity in man was assessed in an experimental model of cathartic induced secretory diarrhoea as well as in acute diarrhoea of presumed infectious origin. In six healthy volunteers receiving castor oil and pretreated with acetorphan or placebo in a crossover controlled trial, the drug significantly decreased the number and weight of stools passed during 24 hours. About 200 outpatients with severe acute diarrhoea (more than five stools per day) were included in a randomised double blind study of acetorphan against placebo. The significant antidiarrhoeal activity of acetorphan was established using a variety of criteria: (i) the duration of both diarrhoea and treatment were diminished; (ii) no acetorphan treated patient withdrew from the study whereas five dropped out because of worsening in the placebo group; (iii) the frequency of symptoms associated with diarrhoea--for example, abdominal pain or distension, nausea and anorexia--remaining after two weeks was nearly halved; (iv) using visual analogue scales acetorphan treatment was found more effective than placebo by both investigators and patients. There was statistically no significant difference between acetorphan and placebo in respect of side effects, particularly constipation, which often accompanies the antidiarrhoeal activity of mu opioid receptor agonists this difference is attributable to the lack of antipropulsive activity of acetorphan in man. The efficacy and tolerance of acetorphan suggest that enkephalinase inhibition may represent a novel therapeutic approach for the symptomatic management of acute secretory diarrhoea without impairing intestinal transit.     

Saccharomyces boulardii Inhibits Water and Electrolytes Changes Induced by Castor Oil in the Rat Colon

The biotherapeutic agent Saccharomyces boulardii has been shown to inhibit castor oil-induced diarrhoea in rats. The present study investigated the mechanism(s) of this antidiarrhoeal effect in terms of water and electrolyte (sodium, potassium and chloride) changes using two rat models. A single oral dose of S. boulardii of up to 12 × 10¹⁰ CFU/kg of viable cells did not inhibit castor oil-induced fluid secretion in the enteropooling model. However, the yeast dose dependently reduced castor oil induced fluid secretion into the colon, with a significant protection at 12 × 10¹⁰ CFU/kg. In this model, castor oil reversed net sodium and chloride absorption into net secretion, and increased net potassium secretion into the lumen. Single pre-treatment with S. boulardii at 4 and 12 × 10¹⁰ CFU/kg dose dependently decreased these electrolyte changes. In conclusion, S. boulardii possesses potent anti-secretory properties versus water and electrolyte secretion induced by castor oil in the rat colon.     

Antidiarrheal activity of Pterocarpus erinaceus methanol leaf extract in experimentally-induced diarrhea

ObjectiveTo investigate the antidiarrheal activity of the methanol leaf extract of Pterocarpus erinaceus in vivo.MethodsThe methanol leaf extract of Pterocarpus erinaceus was evaluated using different doses (100, 200 and 400 mg/kg body weight) orally for antidiarrheal activity using castor oil-induced diarrhea, charcoal meal transit time and castor oil-induced enteropooling in different groups of albino Wistar mice. The activity of the extract at different doses were compared to diphenoxylate (5 mg/kg) and atropine sulphate (3 mg/kg) which were used as standard reference drugs and also to the distilled water administered negative control group of mice.ResultsThe extract at the doses used caused a significant (P< 0.01) reduction in the wet faeces passed by the mice in the castor oil-induced diarrhea, decreased the distance travelled by the charcoal meal by up to 54.8% and also caused a dose dependent and significant (P< 0.001) reduction in the intraluminal fluid accumulation in the castor oil-induced enteropooling.ConclusionsOur results indicate that Pterocarpus erinaceus extract produced significant antidiarrheal activity and the action may attribute to inhibition of gastrointestinal movement and fluid secretion.     

Addition of castor oil as a booster in colon capsule regimens significantly improves completion rates and polyp detection

BACKGROUND Incomplete excretion rates are problematic for colon capsule endoscopy(CCE). Widely available booster regimens are suboptimal. Recently published data on one day preparation CCE protocol using castor oil appeared effective.AIM To assess the impact of adding castor oil to a standard split-dose(2-d) preparation in an unselected Western patient cohort.METHODS All patients aged 18 or more referred to our unit for a CCE over a 5-mo period were prospectively recruited. Controls were retrospectively identified from our CCE database. All patients received split bowel preparation with Moviprep~? [polyethylene glycol(PEG)-3350, sodium sulphate, sodium chloride, potassium chloride, sodium ascorbate and ascorbic acid for oral solution; Norgine B. V, United States], a PEG-based solution used predominantly in our colonoscopy practice. Control booster regimen included Moviprep~? with 750 m L of water(booster 1) on reaching the small bowel. A further dose of Moviprep~? with 250 m L of water was given 3 h later and a bisacodyl suppository(Dulcolax~?) 10 mg after 8 h, if the capsule was not excreted. In addition to our standard booster regimen, cases received an additional 15 m L of castor oil given at the time of booster 1. A nested case control design with 2:1 ratio(control:case) was employed. Basic demographics, completion rates, image quality, colonic transit time, diagnostic yield and polyp detection were compared between groups, using a student t or chi-square tests as appropriate.RESULTS One hundred and eighty-six CCEs [mean age 60 years(18-97), 56% females, n = 104], including 62 cases have been analysed. Indication breakdown included 96 polyp surveillance(51.6%), 42 lower gastrointestinal symptoms(22.6%), 28 due to incomplete colonoscopy(15%), 18 anaemia(9.7%) and 2 inflammatory bowel disease surveillance(1.1%). Overall, CCE completion was 77%(144/186), image quality was adequate/diagnostic in 91%(170/186), mean colonic transit time was 3.5 h(0.25-13), and the polyp detection rate was 57%(106/186). Completion rates were significantly higher with castor oil, 87% cases(54/62) vs 73% controls(90/124), P = 0.01. The number needed to treat with castor oil to result in an additional complete CCE study was 7, absolute risk reduction = 14.52%, 95% confidence interval(CI): 3.06-25.97. This effect of castor oil on excretion rates was more significant in the over 60 s, P 0.03, and in females, P 0.025. Similarly, polyp detection rates were higher in cases 82%(51/62) vs controls 44%(55/124), P = 0.0001, odds ratio 5.8, 95%CI: 2.77-12.21. Colonic transit times were similar, 3.2 h and 3.8 h, respectively. Image quality was similar, reported as adequate/diagnostic in 90%(56/62) vs 92%(114/124).CONCLUSION In our capsule endoscopy centre, castor oil addition as a CCE booster significantly improved completion rates and polyp detection in an unselected Western cohort.     

Electrochemical detector for breath hydrogen determination: measurement of small bowel transit time in normal subjects and patients with the irritable bowel syndrome.

A method is described for the measurement of hydrogen in expired air, using an electrochemical detector. The apparatus is simple to use and sensitive. Its application is illustrated by studies of small bowel transit time made by measuring the time between oral ingestion of the unabsorbable carbohydrate lactulose and a rise in the concentration of hydrogen in expired air. In 20 control subjects transit time was 93.0 +/- 6.6 minutes, while in 16 patients with diarrhoea due to the irritable bowel syndrome it was 54.1 +/- 6.3 minutes (P less than 0.001), suggesting an abnormality in small intestinal motility in these patients. Loperamide, a potent antidiarrhoeal agent, increased transit time in 12 of these patients from 56.3 +/- 6.7 to 100.0 +/- 10.2 minutes (P less than 0.001).     

Antidiarrhoeal properties of a novel sigma ligand (JO 2871) on toxigenic diarrhoea in mice: mechanisms of action

BACKGROUND AND AIMS: Sigma ligands display antisecretory activity against various secretagogues, suggesting antidiarrhoeal properties. In this study, we evaluated: (i) the antidiarrhoeal effect of JO 2871, a high affinity sigma ligand, in three models of toxigenic diarrhoea in mice; and (ii) the site and mechanism of action of this compound. METHODS: Faeces were collected after toxin or vehicle administration in male DBA2 or NMRI mice. Diarrhoea was determined by cumulative stool weight (mg) over a 120 minute period. Diarrhoea was induced by intravenous administration of Salmonella enteriditis lipopolysaccharide (LPS), or oral administration of Escherichia coli heat stable (E coli-sta) or Clostridium difficile toxins. Two sigma ligands, igmesine and JO 2871, were administered either orally or intravenously, 60 and 30 minutes before the toxins, respectively. JO 2871 was also given orally 30 minutes after E coli-sta. In addition, JO 2871 was administered intracerebroventricularly five minutes before LPS and E coli-sta. BMY 14802 (1000 microg/kg orally), a sigma receptor antagonist, or cyclosomatostatin (CSS 1 microg/kg intravenously), a somatostatin antagonist, were given five minutes prior to JO 2871 in LPS, E coli-sta, and C difficile toxin treated mice. Gastric emptying and intestinal transit were evaluated after oral JO 2871 and BMY 14802 and intravenous CSS. RESULTS: Stool weight measured 120 minutes after administration of the toxins was significantly increased. Oral JO 2871 and igmesine dose dependently inhibited toxigenic diarrhoea in all models. ED(50) values obtained using JO 2871 (1-20 microg/kg) were more than 40 times lower than those obtained with igmesine. Oral JO 2871 given after E coli-sta also inhibited diarrhoea in a dose dependent manner (ED(50) 50 microg/kg). Both sigma ligands were active by the intravenous route on LPS and E coli-sta induced stool weight increases. JO 2871 administered intracerebroventricularly failed to block this effect at any dose tested. Both BMY 14802 and CSS reversed the antidiarrhoeal effect of oral JO 2871. JO 2871, BMY 14802, and CSS did not affect transit parameters. CONCLUSIONS: JO 2871 exerts a potent oral antidiarrhoeal effect, acting peripherally through sigma sites and somatostatin release.     

Effect of codeine and loperamide on upper intestinal transit and absorption in normal subjects and patients with postvagotomy diarrhoea.

Patients with chronic severe diarrhoea after truncal vagotomy and pyloroplasty are often difficult to treat using conventional antidiarrhoeal drugs and remain severely disabled. We examined the effect of two drugs, codeine phosphate and loperamide, on upper intestinal transit and carbohydrate absorption, measured non-invasively by serial exhaled breath hydrogen monitoring, in patients with postvagotomy diarrhoea who had previously failed to gain relief from drug therapy. Orocaecal transit was consistently faster in these patients than a group of controls and was associated with malabsorption of glucose. Codeine phosphate 60 mg significantly delayed transit in patients and controls and was associated with a reduction in glucose malabsorption and improvement in symptoms. Loperamide also delayed transit and improved symptoms, but the doses required for this effect (12-24 mg) were higher than usually considered necessary in secretory diarrhoea. These studies indicate that rapid intestinal nutrient transit and associated malabsorption is a factor in the development of diarrhoea postvagotomy and that symptomatic relief can be achieved in most patients by more rational use of existing drugs.     

Control of muscle tone in the human colon.

Human colonic muscle tone varies diurnally and postprandially in predictable ways. Increased tone reduces the capacity of the colon to store contents after a meal, whereas increased distensibility (lesser tone) during sleep enlarges the storage capabilities and may slow transit. We tested the hypothesis that antidiarrhoeal drugs would also alter tone which, in turn, might reduce diarrhoea by facilitating the storage and salvage of fluids. Using a colonic barostat to create low pressure, isobaric colonic distension in healthy volunteers, we found that intravenous atropine (0.01 mg/kg) relaxed the colon during fasting, reduced the postprandial increase in tone, and enhanced relaxation in the late (1-2 hour) postprandial period. Intravenous morphine (0.1 mg/kg) caused variable effects soon after injection but, in fasting subjects, the descending colon relaxed 70-90 minutes after morphine. These changes in colonic motility were not always obvious by conventional manometric recording. Colonic distensibility is increased by antidiarrhoeal drugs and this effect may contribute to their efficacy in slowing colonic transit and augmenting absorption.     

Influence of olsalazine on gastrointestinal transit in ulcerative colitis.

The effect of olsalazine on stool output and the transit of a solid radiolabelled meal through the stomach, small intestine and colon was studied in six patients with ulcerative colitis intolerant of sulphasalazine. Olsalazine 250 mg four times daily significantly accelerated gastric emptying (mean +/- SD; 45.3 +/- 24.2 min v 67.3 +/- 33.1 min, p less than 0.05), mouth to caecum transit time (242 +/- 41 min v 325 +/- 33 min, p less than 0.02) and whole gut transit time (60.5 +/- 26 h v 37.8 +/- 17.8 h, p less than 0.05). No significant changes were seen in mean daily stool weight (215 +/- 41 g v 162 +/- 62 g) and mean daily stool frequency (2.2 +/- 0.6 v 2.4 +/- 1.8). None of these patients developed diarrhoea, but acceleration of gastric and intestinal transit may be responsible for the diarrhoea reported in some patients taking this drug.     

Magnesium citrate-bisacodyl regimen proves better than castor oil for colonoscopic preparation

BACKGROUND: A clean colon preparation prior to endoscopy or X-ray examination is essential to obtain an accurate diagnosis. In order to determine which of two easily made preparations is better, this study compares colon cleansing efficacy, patient acceptance and side effects in patients given either a magnesium citrate-bisacodyl or a castor oil regimen prior to colonoscopy. METHODS: Seventy outpatients scheduled for colonoscopy were randomized to receive one of two bowel evacuation regimens on the day prior to the examination. Group 1 (n = 36) received a magnesium citrate solution (250 mL) and bisacodyl (10 mg, orally). Group 2 (n = 34) received castor oil (60 mL, orally). RESULTS: The cleansing effect of the magnesium citrate-bisacodyl regimen was significantly better than that of castor oil in the ascending colon and caecum (cleansing scores 5.2+/-1.2 vs 3.5+/-1.3, P< 0.0001), but similar to that of castor oil in the recto-sigmoid, descending and transverse colon. Abdominal pain (38 vs 11%, P< 0.01) and nausea (29 vs 8%, P<0.05) were significantly more common in patients receiving the castor oil preparation than in patients administered with the magnesium citrate-bisacodyl regimen. More patients complained of poor acceptance with the castor oil regimen than with the magnesium citrate-bisacodyl regimen (24 vs 8%, P=0.06). CONCLUSIONS: A combined oral magnesium citrate and bisacodyl regimen is effective and better than castor oil for colonoscopic preparation.     

Castor oil as booster for colon capsule endoscopy preparation reduction: A prospective pilot study and patient questionnaire

BACKGROUNDPreparation for colon capsule endoscopy (CCE) requires a large liquid laxative volume for capsule excretion, which compromises the procedure''s tolerability.AIMTo assess the safety and utility of castor oil-boosted bowel preparation.METHODSThis prospective cohort study including 20 patients (age range, 16-80 years; six men and 14 women) suspected of having colorectal disease was conducted at Kindai University Hospital from September 2017 to August 2019. All patients underwent CCE because of the following inclusion criteria: previous incomplete colonoscopy in other facility (n = 20), history of abdominal surgery (n = 7), or organ abnormalities such as multiple diverticulum (n = 4) and adhesion after surgery (n = 6). The exclusion criteria were as follows: Dysphagia, history of allergic reactions to the drugs used in this study (magnesium citrate, polyethylene glycol, metoclopramide, and castor oil), possibility of pregnancy, possibility of bowel obstruction or stenosis based on symptoms, or scheduled magnetic resonance imaging within 2 wk after CCE. The primary outcome was the capsule excretion rate within the battery life, as evaluated by the total large bowel observation rate, large bowel transit time, and bowel creasing level using a five-grade scale in different colorectal segments. The secondary outcomes were complications, colorectal lesion detection rates, and patients’ tolerability.RESULTSThe castor oil-based regimen was implemented in 17 patients. Three patients cancelled CCE because they could tolerate castor oil, but not liquid laxatives. The capsule excretion rate within the battery life was 88% (15/17). The mean large bowel transit time was 236 min. Approximately 70% of patients had satisfactory colon cleansing levels. CCE detected colon polyps (14/17, 82%) and colonic diverticulum (4/12, 33%). The sensitivity, specificity, and diagnostic accuracy rates for detecting colorectal polyps (size ≥ 6 mm) were 76.9%, 75.0%, and 76.4%, respectively. The sensitivity, specificity, and diagnostic accuracy rates for detection of diverticulum were 100% each. Twelve patients (71%) rated CCE as more than “good”, confirming the new regimen’s tolerability. No serious adverse events occurred during this study.CONCLUSIONThe castor oil-based regimen could reduce bowel preparation dose and improve CCE tolerability.     

Surface vibration analysis (SVA): a new non-invasive monitor of gastrointestinal activity.

A computerised system for measurement of vibration at the abdominal surface was constructed which was addressed to the evaluation of gastrointestinal (GI) motor function. Preliminary studies revealed a dominant low frequency signal which was synchronous with the heartbeat and was considered representative of aortic pulsation. This was excluded by selective spectral filtration. The remaining signal was processed and measured by computer, with provision of quantitative energy values as well as of graphic display. The developed method, called surface vibration analysis (SVA) has been evaluated clinically; (a) against oral to caecal transit times (OCCT) of a standard solid meal, in five patients with severe postgastrectomy diarrhoea, seven patients with mild idiopathic diarrhoea and 22 healthy volunteers. (b) against prokinetic effects of a gastrointestinal stimulant (cisapride) in nine patients. In (a) postprandial SVA energy measurements were greater (SVA [*X (SEM)] = 406,933 (98,224] and oral to caecal transit of the solid meal was more rapid (OCTT = *90 (29) min) in the severe diarrhoea patients [postgastrectomy] than either the mild diarrhoea group (*SVA = 235,317 (50,780); *OCTT = *199 (42) min) or normal volunteers (*SVA = 212,062 (27,153); *OCTT = 242 (19) min) [p less than 0.01 for SVA and OCTT]. In the total group, an inverse correlation was observed between quantitative SVA energy values and oral to caecal transit times of solids (Spearman's rho = -0.486; p less than 0.01). In (b), drug stimulation of the GI tract caused an increase of fasting SVA measurements from *21,217 (5956) [before] to *41,937 (9606) [after] intravenous cisapride (p less than 0.05). This new technique may be useful for evaluation of gastrointestinal motor activity.     

Effective treatment of diabetic diarrhoea with somatostatin analogue, octreotide.

A 22 year old insulin dependent diabetic with high volume, secretory chronic diarrhoea refractory to standard andiarrhoeal drugs was treated with the somatostatin analogue octreotide, 50 micrograms twice daily by subcutaneous injection. She improved markedly with a decrease in mean stool weight from 1170 g/24 h range 440-2900 g) to 440 g/24 h (range 180-800 g) (p < 0.05). Stool frequency also decreased from six (range two to 12) to one (range one to three) bowel movements per day (p < 0.01). Mouth to caecum transit time increased from 45 minutes to > 210 minutes, although total gut transit time was unchanged and remained rapid at nine hours. Thus octreotide can reduce stool volume and frequency in high volume diabetic diarrhoea when conventional antidiarrhoeal agents have failed. Its therapeutic benefit appeared to be predominantly related to a marked increase in mouth to caecum transit time.     

Double-blind placebo-controlled study of loperamide (Imodium) in chronic diarrhoea caused by ileocolic disease or resection.

Loperamide (R 18 553) was compared with placebo in a double-blind crossover study of 21 patients with chronic diarrhoea caused by ileocolic disease or resection. Eighteen patients completed the trial. At a median daily dose of 6 mg the new antidiarrhoeal preparation was found to be superior to placebo in controlling chronic diarrhoea. The frequency and weight of stools significantly decreased, the stools became more solid, and carmine transit time was prolonged during loperamide therapy. Loperamide was consistently preferred to placebo by the patients. Gastrointestinal side-effects were few and comparable during both treatment periods.     

Antidiarrhoeal efficacy of Mangifera indica seed kernel on Swiss albino mice

ObjectiveTo examine the antidiarrhoeal activity of alcoholic and aqueous seed kernel extract of Mangifera indica (M. indica) on castor oil-induced diarrhoeal activity in Swiss albino mice.MethodsMango seed kernels were processed and extracted using alcohol and water. Antidiarrhoeal activity of the extracts were assessed using intestinal motility and faecal score methods.ResultsAqueous and alcoholic extracts of M. indica significantly reduced intestinal motility and faecal score in Swiss albino mice.ConclusionsThe present study shows the traditional claim on the use of M. indica seed kernel for treating diarrhoea in Southern parts of India.     

A pharmacological evaluation of antidiarrhoeal activity of leaves extract of Murraya koenigii in experimentally induced diarrhoea in rats

ObjectiveTo evaluate anti-diarrhoeal activity of aqueous and alcoholic extract of the leaves of Murraya koenigii (M. koenigii)by using models of castor oil induced diarrhoea, charcoal meal test and PGE₂ induced diarrhoea.MethodsAlcoholic extract (400 mg/kg) and aqueous extract (200 mg/kg) of leaves of Murraya koenigii were used with loperamide as standard. Albino Wistar rats of both sexes weighing between 150–250 g were used for the anti-diarrhoeal activity.ResultsThe result suggested that it could act centrally and inhibit the PGE₂ to give anti-diarrhoeal effects. Result of charcoal meal test also suggested its anti-muscarnic activity.ConclusionsThese findings indicate that aqueous extract of the leaves of M. koenigii displays good anti-diarrhoeal activity, corroborating the folk use of M. koenigii preparations and contributing for its pharmacological validation.     

Gastrointestinal sounds and migrating motor complex in fasted humans

OBJECTIVE: We investigated the relationships among gastrointestinal sounds, gastrointestinal manometric findings, and small intestinal transit time in healthy fasted humans. METHODS: Gastrointestinal sounds acquired with two microphones attached to the upper and lower abdominal walls of healthy subjects were quantified with a computer-aided sound analysis program. Antroduodenal contractions were recorded by manometry. Small intestinal transit time was measured by breath hydrogen testing after intraduodenal administration of lactulose. RESULTS: The sum of the gastrointestinal sound amplitudes (sound index) in both the upper and lower abdomen changed with time, coinciding with the gastric phases of the migrating motor complex. The sound indices in the upper and lower abdomen were 59.0+/-24.8 and 98.1+/-21.6 mV/min in phase 1, 95.5+/-27.9 and 127.4+/-34.9 mV/min in phase 2, and 132.8+/-12.4 and 188.5+/-73.4 mV/min in phase 3, respectively. There were no significant differences among motility phases in terms of the mean duration or frequency of each sound event. Intravenous erythromycin induced phase 3 in the stomach and doubled the sound index. Somatostatin analogue induced phase-3-like clustered contractions in the duodenum, but inhibited antral contractions and decreased the sound index. The small intestinal transit time was shorter and the sound index increased after intravenous metoclopramide, compared with controls. Scopolamine delayed small intestinal transit time and decreased the sound index. CONCLUSIONS: This study is the first to document the relationships between gastrointestinal sounds and the migrating motor complex. The chronological relation between antral motility and gastrointestinal sounds, and the dissimilar effects of erythromycin and somatostatin, suggest that antral contractions increase gastrointestinal sounds, perhaps by supplying gas into the intestine.     

Lactose malabsorption in Greek adults: correlation of small bowel transit time with the severity of lactose intolerance.

Using breath hydrogen analysis after 139 mmol (50 g) oral lactose load, we investigated the prevalence of lactose malabsorption in 200 Greek adults and examined the relationship between symptoms and small bowel transit time. One hundred and fifty subjects had increased breath hydrogen concentrations (greater than 20 ppm) after the lactose load. In these individuals peak breath hydrogen concentration was inversely related to small bowel transit time (r = 0.63, 6 = 6.854, p less than 0.001) and the severity of symptoms decreased with increasing small bowel transit time. Lactose malabsorbers with diarrhoea during the lactose tolerance test had a small bowel transit time of 51 +/- 22 minutes (x +/- SD; n = 90) which was significantly shorter than the small bowel transit time of patients with colicky pain, flatulence, and abdominal distension (74 +/- 30, n = 53; p less than 0.001) and both groups had significantly shorter small bowel transit time than that of asymptomatic malabsorbers (115 +/- 21 n:7; p less than 0.001). When the oral lactose load was reduced to 33 mmol (12 g), the small bowel transit time increased five-fold and the overall incidence of diarrhoea and/or symptoms decreased dramatically. These results indicate that the prevalence of lactase deficiency in Greece may be as high as 75% and suggest that symptom production in lactose malabsorbers is brought about by the rapid passage down the small intestine of the malabsorbed lactose.     

Effect of explosive noise on gastrointestinal transit and plasma levels of polypeptide hormones

AIM: To investigate the effect of firing noise on gastrointestinal transit and probe its mechanism by measuring the levels of plasma polypeptide hormones. METHODS: A total of 64 SD rats were randomly divided into a control group and three stimulating groups. Firing noise of different intensity by sub-machine guns was used as inflicting factor. The effect of firing noise on liquid substance gastrointestinal transit and solid substance gastrointestinal transit was observed by measuring the ratio of carbon powder suspension transmitting and barium sticks transmitting respectively. Plasma levels of polypeptide hormones were measured by radio-immunoassay. RESULTS: The noise accelerated gastrointestinal transit of solid food by more than 80 db;and accelerated gastrointestinal transit of liquid food significantly by more than 120 db. Meantime, plasma levels of plasma motilin (MTL)(157.47±16.08; 151.90±17.08), somatostatin (SS)(513.97±88.77; 458.25±104.30), substance P (SP)(115.52±20.70; 110.28±19.96) and vasoactive intestinal peptide (VIP) (214.21±63.17; 251.76±97.24) remarkably changed also. CONCLUSION: Within a certain intensity range, the firing noise changes the levels of rat plasma gastrointestinal hormones, but the gastrointestinal transit is still normal. Beyond the range, the noise induces plasma hormone levels disturbance and gastrointestinal transit disorder.     

Performance Assessment of Minimum Quantity Castor-Palm Oil Mixtures in Hard-Milling Operation

The necessity to progress towards sustainability has inspired modern researchers to examine the lubrication and cooling effects of vegetable oils on conventional metal cutting operations. Consequently, as an eco-friendly vegetable product, castor oil can be the right choice as Minimum quantity lubrication (MQL) base fluid. Nonetheless, the high viscosity of castor oil limits its flowability and restricts its industrial application. Conversely, palm oil possesses superior lubricity, as well as flowability characteristics. Hence, an attempt has been made to improve the lubrication behavior of castor oil. Here, six castor-palm mixtures (varying from 1:0.5–1:3) were utilized as MQL-fluid, and the values of machining responses viz. average surface roughness, specific cutting energy, and tool wear were evaluated. Furthermore, an integrated Shannon’s Entropy-based Technique for order preference by similarity to ideal solution (TOPSIS) framework was employed for selecting the most suitable volume ratio of castor-palm oil mixture. The rank provided by the TOPSIS method confirmed that 1:2 was the best volume ratio for castor-palm oil mixture. Afterward, a comparative analysis demonstrated that the best castor-palm volume fraction resulted in 8.262 and 16.146% lowering of surface roughness, 5.459 and 7.971% decrement of specific cutting energy, 2.445 and 3.155% drop in tool wear compared to that of castor and palm oil medium, respectively.