Biomedical subjects

P C Gregory

Publications and source records attributed to P C Gregory.

At least 19 recordsLinked to original sources

PubMed2001

occupational physical activity and the development of impaired mobility: the 12-year follow-up of the Baltimore Epidemiologic Catchment Area sample.

OBJECTIVE: To examine the association between occupational physical activity and self-reported disability. DESIGN: Population-based case control analysis of a longitudinal population-based study in east Baltimore. Eligible participants were aged 18 to 29 yr in 1981, had complete information on occupation in 1981, no disability with tasks related to the domain of mobility in 1981, and complete information on mobility function in 1993 (n = 174). Occupations were divided into low, moderate, and high metabolic equivalents based on job category in 1981. The main outcome measure was disability defined by self-report of difficulty in one or more of five exercise mobility tasks in 1993. RESULTS: Of 174 eligible participants, 45 (26%) reported the onset of disability at follow-up in 1993. A crude odds ratio of 0.25 (95% confidence interval, 0.06, 0.82) was found for the association of moderate compared with low occupational physical activity and the risk of incident disability in mobility tasks. After adjustments to control for possible confounders, moderate job metabolic activity (1.8-2.9 Mets) was independently protective against disability in this cohort (odds ratio = 0.25; 95% confidence interval = 0.083, 0.783). CONCLUSION: In this cohort of people aged 18 to 29 yr, a moderate amount of occupational physical activity was protective against disability in mobility tasks.

Adolescent↗

PubMed1998

Effects of intraduodenal administration of tarazepide on pancreatic secretion and duodenal EMG in neonatal calves.

The influence of CCK-A receptor antagonism on pancreatic exocrine secretion and duodenal EMG, and the mechanism(s) involved in CCK-induced pancreatic secretion were studied in conscious calves. Seven 1-week-old calves were fitted with a pancreatic duct catheter, duodenal cannula and duodenal electrodes. Pancreatic exocrine secretion and duodenal EMG were studied following intraduodenal CCK-A receptor antagonist (Tarazepide), intravenous atropine, and intravenous or intraduodenal CCK-8 administrations. Tarazepide decreased duodenal electric activity, reduced interdigestive pancreatic secretion, especially protein; reduced cephalic and early postprandial (milk) induced secretion of bicarbonate and protein. Pancreatic protein secretion to intravenous CCK-8 was little affected by atropine, but was significantly reduced by Tarazepide+/-atropine; in contrast, protein secretion to intraduodenal CCK-8 was abolished by Tarazepide or atropine. We conclude that pre- and especially early postprandial pancreatic secretion are partly controlled via CCK-A (mainly mucosal) mediated mechanisms.

Animals↗

PubMed1996

Gastrointestinal pH, motility/transit and permeability in cystic fibrosis.

I reviewed the literature (1966-1994) concerning gastrointestinal (GI) pH, motility/transit, and permeability in cystic fibrosis (CF). Most studies reported were performed with very small numbers of patients, but even when considered together the published data do not confirm some generally expressed views on these topics. The only clear findings were a high incidence of gastroesophageal reflux in CF; pre- and postprandial duodenal pH is 1-2 U lower in patients with CF than in healthy controls; and small intestinal paracellular permeability is 4-10 times greater than normal in CF. Some patients showed abnormalities of lower esophageal sphincter pressure and of esophageal motility, but apart from one case study other disturbances of GI motility have not been reported. The results of hydrogen breath tests strongly suggest that oro-cecal transit is slowed in CF, but these results must be confirmed by an alternative test. Measurements of colonic transit and colonic permeability have not been reported. The few studies of gastric emptying reported are controversial. Whether GI pH, apart from duodenal pH, is normal in CF or whether a subset of patients has exceptionally acid intestinal contents requiring specialized pancreatic enzyme supplementation to normalize digestion is not clear. Finally, I briefly discuss the findings in relation to their possible impact on the pathogenesis of fibrosing colonopathy.

Cystic Fibrosis↗

PubMed1995

Control of gastric emptying in the pig: influence of cholecystokinin, somatostatin and prokinetic agents.

The influence of systemic arterial infusions of cholecystokinin octapeptide (CCK8) and somatostatin, and injections of cisapride, metoclopramide and atropine on gastric emptying were studied in eight pigs. Gastric emptying of dry matter (DM) and liquids (Cr-EDTA as marker) was measured, in pigs fitted with a gastric cannula, by evacuation of gastric contents either immediately after the pigs had finished feeding, or 3 h after being fed a meal containing 1200 g of a finely ground barley diet mixed with 2.41 water. Gastric emptying of DM and liquids during the feeding period was not significantly altered by cisapride (0.15 and 0.3 mg kg-1-1), metoclopramide (0.2 mg kg-1), CCK8 (250 ng kg-1 h-1) or somatostatin (1.8 and 4.5 micrograms kg-1 h-1); atropine (0.06 mg kg-1) slowed emptying of DM (by 53 +/- 6%; P < 0.001) and of liquids (by 51 +/- 7%, P < 0.01). In contrast, the amount of DM emptied within 3 h of feeding was significantly reduced with CCK8 (250 ng kg-1 h-1; by 14 +/- 3%, P < 0.001) and with somatostatin (1.8 microgram kg-1 h-1; by 10 +/- 4%; P < 0.001). There was no increase in emptying of DM or liquids with cisapride or metoclopramide; indeed, there was actually a reduction in liquid emptying (by 13 +/- 6%; P < 0.05) with cisapride (0.3 mg kg-1).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1995

Effect of neural blockades, gastrointestinal regulatory peptides, and diversion of gastroduodenal contents on periodic pancreatic secretion in the preruminant calf.

The role of nerves, gastrointestinal peptides, and gastroduodenal contents in the regulation of pancreatic periodic function were studied in preruminant calves. Nine male, Friesian calves were surgically fitted with pancreatic and duodenal catheters, abomasal and duodenal cannulae, and duodenal electrodes. Pancreatic secretion oscillated in phase with the duodenal migrating myoelectric complex. Pancreatic secretion and duodenal motility were abolished by intravenous atropine (5 micrograms.kg-1.min-1). The frequency of pancreatic and duodenal cycles was similarly increased by motilin and decreased by pituitary adenylate cyclase activating polypeptide-27; secretin lengthened duodenal but not pancreatic cycles, resulting in loss of synchronization; cholecystokinin-8 and secretin increased pancreatic secretion (all infusions at 120 pmol.kg-1.h-1); intraduodenal lidocaine (2%) or diversion of gastroduodenal contents reduced pancreatic secretion without altering periodicity. In conclusion, generation of pancreatic as well as of duodenal periodicity in the calf depends upon cholinergic neural efferent input. Secretin, cholecystokinin-8, pituitary adenylate cyclase activating polypeptide, duodenal contents, and mucosal afferent receptors seem to have relatively minor regulatory roles but can modulate the level of pancreatic secretion. The importance of enteric neural influence from the duodenum and the role of motilin in the regulation of pancreatic periodicity and its synchronization with the duodenal motility cycle remain to be determined.

Anesthetics, Local↗

PubMed1995

Induction of apoptotic DNA fragmentation and c-jun downregulation in human myeloid leukemia cells by the permeant Ca2+ chelator BAPTA/AM.

The permeant Ca2+ chelator acetoxymethyl-1,2-bis(2-aminopheoxy)ethane- N,N,N',N'-tetraacetic acid (BAPTA/AM), an agent previously used to characterize drug-induced apoptosis in neoplastic cells, has been examined with respect to induction of DNA fragmentation and cytotoxicity in the human leukemia cell lines HL-60 and U937. Exposure of cells to various concentrations of BAPTA/AM for 6 h resulted in a biphasic induction of internucleosomal DNA cleavage, with maximal damage occurring at 10-microM concentrations. Higher BAPTA/AM concentrations were associated with the loss of internucleosomal cleavage products, but with the appearance of larger (i.e., 50-kilobase) fragments on pulsed-field gel electrophoresis. Cells exposed to 10 microM BAPTA/AM exhibited classic apoptotic morphology, whereas cells exposed to 50-microM concentrations displayed atypical features (e.g., cell swelling, chromatin clumping); in each case, substantial cytotoxicity was noted. The actions of BAPTA/AM did not depend upon the presence of extracellular Ca2+, nor were they affected by impermeant Ca2+ chelators. Measurement of cytosolic Ca2+ by Fura-2/AM or Indo-1 revealed late but not early increases in intracellular Ca2+ in BAPTA/AM-treated cells. Finally, BAPTA/AM-induced apoptosis was accompanied by the concentration-dependent downregulation of the immediate early response gene c-jun. These findings suggest a complex role for Ca2+ chelators such as BAPTA/AM in the regulation of human myeloid leukemic cell apoptosis, and indicate that this agent may selectively antagonize internucleosomal DNA fragmentation without interfering with other aspects of the apoptotic response and/or cell lethality.

Apoptosis↗

PubMed1992

Course of motor recovery in the zone of partial preservation in spinal cord injury.

Thirty-nine C4 to C6 motor complete Frankel A or B spinal cord injured subjects were included in this prospective study to determine the course of recovery in the zone of partial preservation (ZPP) during the first 6 months postinjury. Subjects had initial manual muscle testing and neurologic examination between 3 and 7 days postinjury. Subjects whose most rostral key muscle in the ZPP had a motor power of grade 1 or 1+/5 (group 1, n = 22) were compared with subjects whose most rostral key muscle had a motor power of grade 2 or 2+/5 (group 2, n = 17). Subjects had manual muscle testing weekly for 1 month and then monthly for 6 months postinjury. Comparisons were made for recovery to: (1) grade 3/5; (2) grade 4/5; (3) an increase of one grade; and (4) an increase of two grades. Analyses were made at monthly intervals by the Fisher Exact test and between median times of recovery by the Kruskal-Wallis Ranking test. There was earlier recovery to grade 3/5 for group 2. At one month 11 of 17 (65%) group 2 subjects had reached grade 3/5 compared with 4 of 22 (18%) group 1 subjects (p less than 0.01). At 2 months postinjury, 14 of 17 (82%) group 2 subjects versus 10 of 22 (45%) group 1 subjects had reached grade 3/5 strength (p less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1990

Pattern of gastric emptying in the pig: relation to feeding.

The aims of the present study were to compare the gastric emptying of dry matter (DM) and liquids during the feeding period with that following meal consumption, to clarify the relationship between feeding and gastric emptying, and to investigate how gastric emptying changes in growing animals. The studies were performed in pigs fitted with a gastric cannula and fed on a normal finely ground solid diet mixed with water containing CrEDTA as liquid marker. Gastric emptying was measured using a gastric evacuation technique. It was observed that between 0.75 and 6 h after feeding the total amounts emptied increased, but the proportion of the meal emptied fell, with increase in meal size; emptying of both DM and liquids with large and small meals followed an exponential pattern. In contrast, while the animals were feeding, there was linear and rapid emptying of both DM and liquids following a very short (approximately 2 min) lag phase before emptying began. The rate of emptying increased linearly with body-weight (by 0.055 g DM/min and by 0.24 ml/min per kg body-weight over the range 58-200 kg) such that the emptying of digestible energy per kg metabolic body-weight (W0.75) was roughly maintained (between 2.9 and 3.2 kJ/min per kg W0.75). This suggests that the rate of emptying may be linked in some way with the metabolic requirements of the body. The biphasic pattern of gastric emptying observed is probably the intrinsic pattern of emptying of a meal which does not require breakdown of particles before emptying can occur.

Animal Feed↗

PubMed1989

Duodenal infusion of fat, cholecystokinin secretion and satiety in the pig.

The influence of the cholecystokinin (CCK) antagonist L-364,718 (0.1 mg/kg) on short-term control of food intake was studied in 6 pigs. Arterial injection of L-364,718 abolished the inhibition of intake to CCK octapeptide infusion (4 micrograms/kg/hr; from 42% p less than 0.001, to 97% of control intake), but did not alter control intake (99%). Injection of L-364,718 also abolished the inhibition of intake to duodenal infusion of emulsified fat (12 g/hr; from 76% p less than 0.001 to 105%) and of monoglyceride (24 g/hr; from 64% p less than 0.001 to 101%), but did not alter the inhibition to oleic acid (60 g/hr; 48% p less than 0.01 and 61% p less than 0.02), to glycerol (127 g/hr; 84% p less than 0.05 and 89%) or to glucose (144 g/hr; 78% p less than 0.02 and 69% p less than 0.001). These results suggest that monoglyceride-induced CCK secretion is mainly responsible for the satiety to duodenal fat in the pig, but that there is also a CCK-independent effect via the fatty acid. The results further indicate that intake of a normal barley-based diet (2% fat) is controlled via CCK-independent mechanisms.

Animals↗

PubMed1989

Relation between gastric emptying and short-term regulation of food intake in the pig.

The relation between gastric emptying (GE), measured by gastric evacuation, and food intake (FI) was studied in pigs fed two meals to appetite per day. Duodenal infusion of emulsified fat (Intralipid; KabiVitrum) inhibited both FI and GE of digestible energy by more than the energy infused, but the gastric volume at satiety was more than 20% below the control. Duodenal infusions of glucose inhibited FI calorically, and generally inhibited GE calorically; but gastric volume at satiety was always equal to control volume. Thus GE (via gastric distension) may regulate FI to duodenal infusion of glucose but not to Intralipid. In pigs given no infusions, removal of the gastric contents immediately prior to the p.m. meal increased intake by 10%, However, when the contents were retained the pigs ate two equal-sized meals in the day, even though the gastric volume after the p.m. meal was 24% greater than after the a.m. meal. Therefore, although gastric volume may influence intake it cannot be the only factor determining satiety on this diet.

Animals↗

PubMed1989

Control of gastric emptying in the pig: influence of duodenal infusions of glucose and emulsified fat.

The influence of duodenal infusions of emulsified fat (20% Intralipid) and glucose (40%, w/v) on gastric emptying during the feeding period was studied in five pigs. Gastric emptying was measured by evacuation of gastric contents immediately the pigs had finished feeding in animals fitted with a gastric cannula and a duodenal catheter and fed a solid meal mixed with water. Infusions at various rates of Intralipid and glucose given either from the start of feeding or up to 30 min prior to feeding until the pigs had finished feeding inhibited gastric emptying of dry matter (DM) and liquids in a qualitatively similar but quantitatively different manner. With both infusions the rates of gastric emptying of DM and liquids were progressively reduced with pre-infusions of 0, 10, 20 and 30 min. Slow infusions of Intralipid (2.3 and 4.6 ml/min) inhibited gastric emptying of DM and liquids to a greater extent than equicaloric infusions of glucose (3 and 6 ml/min), but faster infusions of Intralipid (6 ml/min) inhibited emptying less than equicaloric infusions of glucose (8 ml/min). When the DM emptied was converted into digestible energy (DE) there was no evidence that Intralipid inhibited gastric emptying calorically. In contrast the results showed that there was caloric regulation of gastric emptying with infusions of glucose begun at the start of feeding. There was a linear reduction in the rate of DM emptied with increase in the rate of glucose infusion (2-8 ml/min) of 64.5 +/- 4.8 g DM per MJ/min glucose infused, i.e. equivalent to a reduction of 0.98 +/- 0.07 kJ/min DE emptied for each kJ/min glucose infused. These changes in gastric emptying with duodenal infusions of glucose and Intralipid mirror the changes previously observed in food intake following similar infusions, and the results are therefore compatible with control of gastric emptying being an important site of short-term regulation of food intake in the pig.

Animals↗

PubMed1989

Influence of duodenal digesta composition on abomasal outflow, motility and small intestinal transit time in sheep.

1. A study was made of the influence of duodenal infusion of some of the components of the digesta on gastrointestinal motility, abomasal outflow and small intestinal transit time in seven sheep fed 1500 g grass pellets/day. Gastrointestinal motility was recorded by electromyography. Abomasal outflow was estimated according to the rate of dilution of CrEDTA injected and sampled via an abomasal catheter. Small intestinal transit time was measured by the passage of Phenol Red from the duodenum to the terminal ileum. 2. Abomasal outflow was inhibited during 3 h infusions (5 ml/min) of 100 mM-acetic, propionic, butyric and lactic acids, of 50 mM-HCl, of 0.56 M-glucose, and of 2 and 4% protein hydrolysate. Abomasal motility was inhibited by these infusions and by infusion of 234 mM-oleic acid (0.75 ml/min), of a fat emulsion (Intralipid 20% 0.3 ml/min) and of 50 mM-L-tryptophan (7.5 ml/min). 3. Abomasal motility and, where tested, abomasal outflow, were not affected by duodenal infusion of 150 mM-NaHCO3 (5-10 ml/min), 0.28 M-NaC1 (5-7.5 ml/min), distilled water (5-7.5 ml/min), 25 mM-L-tyrosine (5 ml/min), and of 50 mM-acetic, propionic, butyric and lactic acids (5 ml/min). 4. At concentrations or rates of infusion above the threshold dose needed to inhibit abomasal motility, small intestinal motility was altered and the frequency and amplitude of the reticulo-ruminal contractions were inhibited. 5. The transit time through the small intestine was increased during infusion of 100 mM-acetic, propionic, butyric and lactic acids and decreased during infusion of 0.56 M-glucose and Intralipid. 6. Inhibition of abomasal motility and outflow in sheep receiving 1500 g/day grass pellets was calculated to require increases in the duodenal concentration of volatile fatty acids of about 150% and K+ of about 38%, and to require an increase in the rate of delivery to the duodenum of H+ of about 90%, nitrogen of about 22% glucose of about 2000% and fat of about 84%. 7. These findings are discussed in relation to the composition of abomasal and duodenal digesta in sheep fed different diets. 8. It seems likely that components of duodenal chyme, such as H+, volatile fatty acids, glucose and fat only affect abomasal outflow in sheep fed high-grain diets (glucose, volatile fatty acids), or diets highly supplemented with fat (fat), for short periods after meal feeding (volatile fatty acids) or under abnormal conditions (H+).(ABSTRACT TRUNCATED AT 400 WORDS)

Abomasum↗

PubMed1987

The influence of gastrointestinal infusions of glucose on regulation of food intake in pigs.

The influence of gastrointestinal infusions of glucose on short-term and 24 h control of food intake was studied in sixteen pigs fed twice per day and nine fed three times per day. The pigs were fitted with up to four catheters each, placed in the stomach, the duodenum and at 2 and 8 m from the ligament of Treitz (l.t.). Infusions were given into the catheters, beginning 30 min before the first meal (two feeds) or second meal (three feeds) of the day, and continuing until the pigs stopped eating. The effects of the infusions on both short-term and 24 h intakes were the same whether the pigs were given two or three feeds per day. Infusions of glucose (400 g/l) into the stomach or small intestine altered short-term (meal) intake, but had no effect on intake at the following meal. With glucose infusion at rates above a threshold level (4 ml/min) to the stomach, duodenum or ileum (8 m from l.t.) food intake at that meal was suppressed such as to compensate for the amount of energy infused. Glucose infusions to the jejunum (2 m from l.t.) caused greater inhibition of short-term intake than infusions elsewhere, and 6 ml/min glucose inhibited intake by more than the amount of energy infused. Duodenal injection of the local anaesthetic lignocaine markedly suppressed the inhibition of intake caused by gastric infusion of glucose. The reductions in intake with glucose infusions at various rates into the stomach or duodenum were nearly identical to those with the same rates of infusion of NaCl at the same high osmolarity. It is concluded that glucose activation of receptors over a large part of the small intestine participates in the short-term control of energy intake in the pig, and that the receptors are activated equally by glucose in terms of an osmotic or caloric stimulus. It is suggested that activation of these receptors is involved in the caloric regulation of gastric emptying leading to gastric distension and inhibition of further intake.

Animals↗

PubMed1987

Inhibition of reticulo-ruminal motility by volatile fatty acids and lactic acid in sheep.

1. A study was made of the influence on reticulo-ruminal motility, recorded by electromyography, of ruminal infusions of volatile fatty acids (VFAs) and lactic acid in twenty-four sheep maintained by intragastric infusion of a complete liquid diet, in three sheep fed grass pellets, and in nine chronically vagotomized sheep; abomasal and duodenal infusions of VFA and lactic acid were tested in five sheep fed grass pellets. 2. Ruminal infusions of VFAs and lactic acid progressively inhibited the amplitude of the reticulo-ruminal contractions. In many experiments there was no effect on contraction frequency until the cessation of all reticulo-ruminal contractions at which point the maximal concentration of VFA recorded in the abomasum was 28 mM, and that of lactic acid was 20 mM. 3. The concentrations of undissociated VFAs causing cessation of reticulo-ruminal contractions in the vagus-intact sheep were very similar to the concentrations causing abolition of the organized intrinsic motility of the chronically vagotomized sheep. 4. The inhibition of reticulo-ruminal motility with ruminal infusions of mixtures of VFAs and of lactic acid together with VFAs could largely be explained by the sum of the effects of the individual acids present. 5. Abomasal infusion of VFA or lactic acid inhibited the amplitude of ruminal, especially primary ruminal, contractions at concentrations of undissociated acid of 60 mM and above and increased the frequency of reticulum and primary ruminal contractions at about 80 mM. 6. Duodenal infusion of VFAs and lactic acid (100 mM, 5 ml/min) strongly inhibited abomasal motility without affecting reticulo-ruminal motility, and at a higher rate (100 mM, 10 ml/min) abolished motility and inhibited both the amplitude and frequency of reticulo-ruminal contractions. 7. It is concluded that the initial inhibition of reticulo-ruminal motility in ruminal acidosis is unlikely to involve any significant influence from duodenal, or abomasal receptors. The final cessation of reticulo-ruminal motility with ruminal acidosis could involve local effects of VFAs in the reticulo-rumen as well as through excitation of acid-sensitive reticulo-ruminal receptors.

Action Potentials↗

PubMed1987

The influence of gastrointestinal infusion of fats on regulation of food intake in pigs.

1. The influence of gastrointestinal infusions of fat on short-term and 24 h control of food intake were studied in twenty-four pigs fed twice per day and seventeen fed three times per day. The pigs were fitted with up to four catheters placed in the stomach, the duodenum, and at 2, 4 and 8 m from the ligament of Treitz. 2. Various infusions were given into the catheters beginning 30 min before the first meal (two feeds) or second meal (three feeds) of the day and continuing until the end of the feeding period or until the pigs stopped eating. 3. Infusions of a fat emulsion (Intralipid) into the stomach, of oleic acid or glycerol into the duodenum, or of glycerol into the ileum (8 m from the ligament of Treitz) inhibited food intake during the infusion according to the amount of energy infused. 4. Food intake was inhibited by more than the amount of energy infused with duodenal infusion of Intralipid or monoglyceride, or with infusion of Intralipid mixed with bile salts and lipase (but not with Intralipid alone) into 2 or 4 m from the ligament of Treitz. 5. Duodenal infusion of glycerol, and ileal (8 m from the ligament of Treitz) infusion of monoglyceride or glycerol inhibited food intake at the following meal according to the amount of energy infused. 6. It is concluded that fats can exert both pre- and post-absorptive control of food intake and that since Intralipid infusion to the stomach but not to the duodenum inhibits food intake according to the amount of energy infused, it is likely that control of food intake is related to control of stomach emptying. 7. The inhibition of food intake by more than the amount of energy infused during upper intestinal infusion of fat is likely to be a result of digestion of the fat to monoglycerides, and interaction of monoglycerides with receptors in the proximal 4 m of intestine.

Animals↗

PubMed1986

The influence of intestinal infusion of fats on small intestinal motility and digesta transit in pigs.

The influence of duodenal and ileal infusion of nutrients on small intestinal transit of digesta, measured by the passage of phenol red marker, was studied in twelve pigs fitted with duodenal and ileal catheters, and a terminal ileal cannula. Changes in gastrointestinal motility were observed by electromyography and by use of an X-ray image intensifier in four of the pigs fitted additionally with nichrome wire electrodes in the gut wall and in seven pigs fitted only with a gastric catheter. Small intestinal transit time was unaffected by intestinal catheterization per se, or by duodenal or ileal infusion of glucose or peptone. It was reduced by duodenal infusion of fat or of some of the products of fat digestion including oleic acid and a monoglyceride containing unsaturated fatty acids (monoglyceride LS) but was not affected by infusion of glycerol, stearic acid or a monoglyceride containing saturated fatty acids (monoglyceride P). Ileal transit time was greatly reduced by ileal infusion of soya bean oil mixed with bile salts and lipase and by monoglyceride LS but not by soya bean oil alone. Total small intestinal transit time was reduced to a lesser degree by ileal infusion of soya bean oil mixed with bile salts and lipase and by monoglyceride LS and was unaffected by soya bean oil alone. The level of irregular spiking activity of the small intestine was greatly reduced by both duodenal and ileal infusion of fat, but rapidly propagated spike bursts were initiated from the point of infusion (identified radiologically as peristaltic rushes) many of which travelled right through to the ileo-caecal junction. It is concluded that intestinal infusion of fat accelerates small intestinal transit in pigs by induction of peristaltic rushes; that since the ileal transit times were more severely reduced than total small intestinal transit times by ileal infusion of fat the response is probably only seen over those areas of intestine in direct contract with the fat; and that the effect depends upon the presence of fat digestion products, i.e. the fatty acid and the monoglyceride, although probably only those containing unsaturated fatty acids.

Animals↗

PubMed1985

The influence of a chronic subclinical infection of Trichostrongylus colubriformis on gastrointestinal motility and digesta flow in sheep.

The influence of a chronic subclinical infection of Trichostrongylus colubriformis, 2500 larvae/day for 12 weeks, on gastrointestinal motility and digesta flow was studied in 12 sheep supplied ad libitum with food and water. Motility was recorded by X-radiography and electromyography from chronically implanted electrodes; abomasal volume and outflow were estimated by dilution of CrEDTA; small intestinal transit time was estimated by passage of Phenol Red. The findings were compared with measurements made prior to infection at restricted food intake and reported separately. The first effects of infection were seen after 3-4 weeks. No animal developed diarrhoea, but food intake was progressively reduced. Small intestinal transit time, abomasal volume and half-time of marker dilution increased while abomasal outflow decreased during infection. These changes occurred both in absolute terms and when compared with values predicted from the observed level of food intake. As the animals became resistant to the parasites abomasal volume and digesta flow returned towards control values (weeks 10-12). The migrating myoelectric complex (MMC) was disrupted in only one sheep, and only transiently. In all sheep the frequency of the MMC was increased during infection and there was a progressive inhibition of abomasal, duodenal and jejunal motility. X-radiography showed there was prolonged pooling of digesta in the proximal small intestine which was cleared only at the phase of regular spiking activity. Two sheep given an anthelmintic drench recovered normal motility and clearance of digesta. It is concluded that subclinical infection of sheep with T. colubriformis alters the normal pattern of gastrointestinal motility in the absence of any diarrhoea, and causes inhibition of abomasal and proximal small intestinal motility and digesta flow. The increased frequency of MMCs helps to maintain digesta flow through the proximal small intestine.

Abomasum↗

PubMed1985

The relation between food intake and abomasal emptying and small intestinal transit time in sheep.

The relation between the level of food intake and gastrointestinal motility and digesta flow in the abomasum and small intestine was studied in sheep fitted with nichrome-wire electrodes in the gut wall, an abomasal and a duodenal catheter and a terminal ileal cannula. Abomasal volume and outflow were calculated from CrEDTA dilution in six sheep and small intestinal transit time by the passage of Phenol Red in ten sheep. The frequency of the migrating myoelectric complex of the small intestine was not altered by the level of food intake but the duration of the periods of irregular spiking activity, the amplitude of abomasal activity and the frequency of duodenal rushes were decreased as the level of food intake was decreased. There was a linear relation between the level of food intake (FI) and abomasal outflow (mean with SEM: 327 (69) ml/h for each kg FI/d; P less than 0.01), and abomasal volume (mean with SEM: 344 (50) ml/kg FI per d; P less than 0.001), without any significant change in the half-time of marker dilution in the abomasum. Small intestinal transit time decreased with an increase in food intake (mean with SEM: -54.9 (5.6) min/kg FI per d; P less than 0.001). It is concluded that abomasal volume and the rate of digesta flow from the abomasum and along the small intestine are linearly related to the level of food intake.

Abomasum↗