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Results for “Digestive System Physiological Phenomena”

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At least 19 recordsLinked to original sources
PubMed2001

Neural mechanisms involved in the delay of gastric emptying and gastrointestinal transit of liquid after thoracic spinal cord transection in awake rats.

Spinal cord transection (SCT) delays gastric emptying (GE), and intestinal and gastrointestinal (GI) transit of liquid in awake rats. This study evaluates the neural mechanisms involved in this phenomenon. Male Wistar rats (N = 147) were fasted for 16 h and had the left jugular vein cannulated followed by laminectomy or laminectomy + complete SCT between T4 and T5 vertebrae. The next day, a test meal (1.5 ml of a phenol red solution, 0.5 mg/ml in 5% glucose) was administered by gavage feeding and 10 min later cervical dislocation was performed. Dye recovery in the stomach, and proximal, mid and distal small intestine was determined by spectrophotometry. SCT inhibited GE and GI transit since it increased gastric recovery by 71.3% and decreased mid small intestine recovery by 100% (P < 0.05). Subdiaphragmatic vagotomy, celiac ganglionectomy + section of the splanchnic nerves, i.v. hexamethonium (20 mg/kg) or yohimbine (3 mg/kg) prevented the development of the SCT effect on GE and GI transit. Pretreatment with i.v. naloxone (2 mg/kg), L-NAME (3 mg/kg) or propranolol (2 mg/kg) was ineffective. Bilateral adrenalectomy or guanethidine (10 mg/kg) increased the magnitude of the GE inhibition, while i.v. prazosin (1 mg/kg) or atropine (0.5 mg/kg) decreased the magnitude but did not abolish the GE inhibition. In summary, the inhibition of GI motility observed 1 day after thoracic SCT in awake rats seems to involve vagal and possibly splanchnic pathways.

Animals↗
PubMedDate not supplied

Transplantation of the urinary bladder and other organs in the subcutaneous tissue induces cyst formation and epithelialization: its potential usefulness in regenerative medicine.

Certain hollow organs are known to form cysts when heterologously transplanted. In order to examine the usefulness of the phenomenon for regenerative medicine, rat urinary bladders and other organs were allo-transplanted under the subcutaneous tissue of the back. These transplanted tissues very often formed cysts covered with epithelia. The epithelia covered an area about twice the original size. In the case of the urinary bladder, the epithelium started moving from the edge of the transplants around day 3 after the operation, and as time proceeded, the tela submucosa and tunica muscularis also moved to encircle the epithelium, and formed the wall of the cyst. The basal laminae were formed under the newly expanded epithelium slightly behind the leading tip. All of the organs tested had the capability of cyst formation and epithelialization, although their rate differed between organs. The results are discussed with reference to the potential use of cyst formation for regenerating damaged organs.

Animals↗
PubMed1997

Healing in the gastrointestinal tract.

Healing in the GI tract is rapid when free of complications: Unlike cutaneous healing, in which progress can be observed on a daily basis and intervention instituted early if necessary, healing of the intestinal anastomosis is anatomically obscured from inspection, allowing the surgeon only the patient's parameters of general well-being to judge the success of the operation. For the same reason, complications usually require re-operation, with the associated morbidity of a laparotomy and additional general anesthetic. This places a great responsibility on the surgeon to be cognizant of all the preoperative, intraoperative, and postoperative factors relating to anastomotic healing that might compromise the healing process. Bearing these in mind, along with attention to technical detail, should limit complications to an acceptable level. Patients most at risk are (1) those who perioperatively develop physiologic problems that lead to shock, hypoxia, and resultant anastomotic ischemia, (2) those with radiation-induced tissue injury, (3) those with sepsis, and (4) those with preoperative bowel obstruction. Malnourishment, malignancy, diabetes, steroids, and age also influence outcome to varying degrees. Future advancement in the field of GI healing lies in our ability to manipulate the early struggle between collagen synthesis and collagen breakdown. A profound understanding of the molecular and biochemical pathways and the factors that control them will bring us closer to this goal. Clinically, this may be accomplished by the introduction of wound healing enhancers into the anastomotic site, possibly by incorporating them into suture materials, biofragmentable anastomotic rings, or staple materials. Already much is known about the influence of different cytokines and growth factors on collagen regulation, knowledge that will help resolve many of the long-standing problems associated with GI surgery.

Anastomosis, Surgical↗
PubMed2002

Epidural analgesia enhances functional exercise capacity and health-related quality of life after colonic surgery: results of a randomized trial.

BACKGROUND: Multimodal analgesia programs have been shown to decrease hospital stay, but it not clear which functions are restored after surgery. The objective of this study is to evaluate the impact of epidural anesthesia and analgesia on functional exercise capacity and health-related quality of life. METHODS: Sixty-four patients undergoing elective colonic resection were randomized to either patient-controlled analgesia with morphine or thoracic epidural analgesia with bupivacaine and fentanyl (epidural group). All patients in both groups received similar perioperative care and were offered the same amount of postoperative oral nutrition and assistance with mobilization. Primary outcome was functional exercise capacity as measured by the 6-min walking test, and secondary outcome was health-related quality of life, as measured by the SF-36 health survey. These were assessed before surgery and at 3 and 6 weeks after hospital discharge. Other variables measured in hospital included pain and fatigue visual analogue scale, bowel function, time out of bed, nutritional intake, complication rate, readiness for discharge, and length of hospital stay. RESULTS: Although the 6-min walking test and the SF-36 physical health component decreased in both groups at 3 and 6 weeks after surgery, the patient-controlled analgesia group experienced a significantly greater decrease at both times (P < 0.01). Patients in the epidural group had lower postoperative pain and fatigue scores, which allowed them to mobilize to a greater extent (P < 0.05) and eat more (P < 0.05). Length of hospital stay and incidence of complications were similar in both groups, although patients in the epidural group were ready to be discharged earlier. CONCLUSIONS: The superior quality of pain relief provided by epidural analgesia had a positive impact on out-of-bed mobilization, bowel function, and intake of food, with long-lasting effects on exercise capacity and health-related quality of life.

Adult↗
PubMed2002

[Physiology of microflora in the digestive tract].

The microflora of the digestive tract is a complex microbial ecosystem, well balanced, which in an aboral direction undergoes specific changes as to the ratio of aerobic and anaerobic microorganisms the functions of which supplement each other--the aerobes ensure for the whole ecosystem the scavenger effect. The microbial profile of the digestive tract is typical by the absence of anaerobic microorganisms in the stomach and conversely their absolute predominance in the distal colon. The basic physiological functions of the microflora of the digestive tract can be characterized as follows: 1. microbial barrier against pathogens and potential pathogens, 2. formation of products of the microflora and their influence on the blood supply of the intestinal mucosa and peristaltics, 3. stimulation of the immune system in the gut, 4. reduction of bacterial translocation, 5. production of vitamins. To this problem in the world literature, contrary to ours, deserved attention has been paid for many years. Knowledge of the problem opens the door to expedient manipulation with the microbial flora of the digestive tract by the use of diet or prebiotics, probiotics as well as antibiotic treatment. The author presents a summary of basic findings which developed on the subject of physiological microflora of the digestive tract successively up to their present shape.

Bacteria↗
PubMedDate not supplied

1997 Harry M. Vars Research Award. Does the route of feeding modify gut barrier function and clinical outcome in patients after major upper gastrointestinal surgery?

BACKGROUND: Direct experimental evidence suggests that total enteral nutrition (TEN) reduces septic morbidity compared with bowel rest and total parenteral nutrition (TPN) and that mucosal support and maintenance of gut barrier function is a key mechanism. This effect is supported indirectly by clinical studies, but this question has not previously been investigated directly in the postoperative patient. This study examined the hypothesis that early enteral feeding after major upper gastrointestinal surgery may modulate gut barrier function and decrease the risk of major infective complications compared with bowel rest and parenteral nutrition. METHODS: A randomized clinical trial of 67 patients (TPN = 34; TEN = 33) fed postoperatively for 7 days was performed. Thirty-day major morbidity and mortality were monitored. Intestinal permeability was measured using the lactulose/mannitol test preoperatively and on postoperative days 1 and 7. Systemic anti-endotoxin core immunoglobulin G and M antibodies and serum albumin and C-reactive protein were quantified at these time points. RESULTS: No clinical benefit was observed in patients fed enterally compared with the parenterally fed group. Intestinal permeability was increased on the 1st postoperative day in association with evidence of endotoxin exposure. By day 7, enteral feeding compared with parenteral feeding had failed to significantly influence any of the gut barrier or systemic parameters. CONCLUSIONS: This randomized controlled trial of TEN vs TPN after major upper gastrointestinal surgery failed to show a clinical benefit for the enteral route. Moreover, enteral nutrition did not modulate gut barrier function postoperatively.

Antibodies↗
PubMed1998

The effects of surgery on gastrointestinal motor activity.

Gastrointestinal surgical procedures have the potential to disrupt motor activity in various organs of the gastrointestinal tract or, indeed, throughout the entire alimentary canal. Several of these motor effects have important clinical consequences and have also served to advance our understanding of the regulation of gastrointestinal motor activity. This review will focus, in particular, on the effects of surgery on the small intestine, and will attempt to emphasize the implications of these studies for our understanding of small intestinal motility, in general.

Digestive System Physiological Phenomena↗
PubMed1997

Considerations for gastrointestinal cannulations in ruminants.

The complexity of ruminant digestion necessitates a greater variety and complexity of experimental methods than with any other species. The fact that dietary ingredients are first subjected to microbial fermentation requires elaborate measures to ascertain nutrients presented for absorption. Numerous approaches have been attempted to obtain representative samples of digesta at sites throughout the gastrointestinal tract. The choices of a researcher before an experiment include animal(s), site(s) for cannula placement, style of cannula, cannula material, and numerous other more subtle factors that may contribute to the success of an experiment. This review compares the advantages and disadvantages of various approaches, cannula types, and cannula materials that should be considered before experiments are conducted.

Animals↗
PubMed2005

Technical Note: Improved technique for fitting pigs with steered ileocecal valve cannulas.

Collection of ileal digesta to evaluate AA digestibilities has become increasingly important in swine nutrition research. Steered ileocecal valve cannulation of pigs permits total collection of ileal digesta, while still allowing normal digesta flow during noncollection periods. This technique was modified and used with 64 crossbred barrows in five trials. Our procedural changes included preoperative i.v. administration of a broad-spectrum antibiotic and nonsteroidal antiinflammatory drug, sharp incision through the muscle layers of the laparotomy wound, use of a heparinized saline lavage solution, replacement of the guide ring with a stylette, and fixing the outer cannula barrel in place with a hose clamp. The current technique involves a right flank laparotomy, parallel and distal to the last rib, with the pig under general anesthesia. A stainless-steel ring (inner ring = 2.0 mm thick, 35.0 mm i.d.) is introduced into the ileal lumen through an enterotomy proximal to the origin of the ileocecal fold. A nylon string attached to this ring is threaded through the ileum and ileocecal valve into the cecum using a silastic stylette, which encases the string. A second stainless-steel ring (outer ring = 2.0 mm thick, 34 mm o.d.) is fixed in place around the ileum, distal to the inner ring and just proximal to the ileocecal valve. A polyurethane cannula barrel (barrel = 100 mm long, 26 mm i.d., 32 mm o.d.; flange = 70 mm o.d.) is introduced into the cecal lumen via an enterotomy through the lateral cecal band and secured in place with two purse-string sutures. The cannula is exteriorized through an incision caudal and proximal to the intial laparotomy site, where it is plugged using a cylindrical stopper (26 mm o.d., 55 mm long) and held in place by a second cannula barrel (barrel = 43 mm length, 33 mm i.d., 41 mm o.d.; flange = 80 mm o.d.). Procedural changes decreased postsurgical complications, as evidenced by decreased seepage around the cannula and fewer and less severe adhesions noted at necropsy. Based on five trials, this technique is a reliable means of collecting ileal digesta for nutrient analyses.

Animals↗
PubMed1991

Autologous perfusion of an isolated rabbit gastrointestinal tract.

Most perfusion techniques rely on mechanical means to provide blood flow to the isolated organ for maintaining its physiological conditions. The approach usually requires a complicated mechanical system with the associated problems of blood type matching and prevention of blood cell damage. This paper describes a gastrointestinal tract perfusion technique that uses the rabbit's own cardiopulmonary system as the autologous blood supply source. The technique allows for the removal of the complete intestinal loop from the abdominal cavity of the rabbit, and maintains its blood circulation through silastic tubing connections of the catheterized portal vein and cranial and caudal mesenteric arteries. An alternative perfusion site that uses the aorta as the arterial blood supply and the vena cava as the venous return also is described. The isolated perfused GI tract may then be placed in a separate test environment for controlled experiments. For an acute animal test, the approach was found to be a convenient alternative to conventional approaches.

Animals↗
PubMed1990

Differential acceleration of healing of surgical incisions in the rabbit gastrointestinal tract by platelet-derived growth factor and transforming growth factor, type beta.

Anastomotic dehiscence is a major cause of morbidity and mortality in gastrointestinal surgery. A unique model system of a gastric incision was developed to test the potential of polypeptide growth factors to enhance wound healing. Paired, deep partial-thickness incisions to but not including the gastric mucosa were made. A single topical application of transforming growth factor, type beta 1 (TGF-beta), platelet-derived growth factor, or control vehicle at the time of wounding was given. Wound breaking strength and detailed histologic analyses of wounds were evaluated as a function of time after wounding. TGF-beta (0.1 to 2.0 micrograms/wound) demonstrated a bimodal, dose-dependent acceleration of wound breaking strength 7 days after gastric wounding. An approximate 4-day acceleration of gastric wound breaking strength by TGF-beta (2 micrograms/wound) was seen at 7 and 11 days. Wounds treated with platelet-derived growth factor (10 micrograms/wound) displayed an increased cellular response but no enhancement of breaking strength at 7 and 11 days. These results demonstrate the ability of TGF-beta to accelerate gastrointestinal tissue repair by topical application and suggest significant potential for the use of growth factors in enhancing repair of surgical wounds of the gastrointestinal tract.

Animals↗
PubMed1989

The effect of initial operative repair on the recovery of intestinal function in gastroschisis.

Recent reports concerning the treatment of gastroschisis suggest that primary closure results in more rapid return of gastrointestinal function, a shortened hospitalization, diminished perinatal complications, and improved long-term survival. A 4-year retrospective review of infants treated for gastroschisis at the University of Florida yielded 30 infants requiring repair of this abdominal wall defect. The series included 19 males and 11 females, and the average abdominal wall defect measured 4 cm in its greatest dimension. Nine infants (mean weight, 2,275 gm) were repaired using a staged closure using a silastic (six) or cutaneous (three) silo. Complete fascial closure was accomplished in an average of 8 days in the silastic group and 15 days in the infants with skin flaps. Mean age at start of enteral feeds was 23 days, with complete oral feedings at 43 days. Twenty-one infants (mean weight, 2,127 gm) underwent primary fascial closure. Three deaths occurred in the perioperative period: one from acute renal failure and two from sepsis secondary to a segment of necrotic intestine. An additional infant developed postoperative necrotizing entercolitis but recovered. Two infants in this group also had jejuno-ileal atresia requiring extensive small bowel resection. In the remaining 15 infants, oral alimentation was initiated for an average of 23 days, with full oral alimentation at 46 days. The data suggest that the recovery of the gastrointestinal system, adequate enough to support total oral alimentation, is unrelated to the initial surgical procedure chosen to obtain fascial closure in the newborn with gastroschisis. In addition, vigorous attempts at primary fascial closure may jeopardize intestinal viability, diminish ventilatory function, and result in unnecessary morbidity and mortality.

Abdominal Muscles↗