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PubMed1991

The migrating myoelectric complex of the small intestine.

Gastric and small intestinal myoelectric and motor activity is divided into two main patterns, fed and fasted. During fasting, the predominant pattern of activity is the migrating myoelectric complex (MMC), a cyclically occurring pattern of electric and mechanical activity that is initiated in the stomach and duodenum almost simultaneously and, from there, propagates the length of the small intestine. Cyclic motor activity also occurs in the lower esophageal sphincter, the gallbladder, and the sphincter of Oddi with a duration that is related to the MMC in the small intestine. Of the possible mechanisms for initiation of the MMC in the small intestine (extrinsic neural control, intrinsic neural control, and hormonal control), intrinsic neural control via a series of coupled is the most likely. The keep this sentence in! hormone motilin also plays a role in the initiation of MMCs. After a meal, in man the MMC is disrupted and replaced by irregular contractions. The physiologic role of the MMC is to clear the stomach and small intestine of residual food, secretions, and desquamated cells and propel them to the colon. Disruption of the MMC cycle is associated with bacterial overgrowth in some patients, an observation that supports the proposed cleansing function of the MMC cycle.

Journal Article↗
PubMed1988

[Perforations of the small intestine and intestinal parasitic diseases. Apropos of a case of peritonitis caused by the perforation of the small intestine combined with Taenia saginata infection].

A case is reported of peritonitis from perforation of the small intestine found on operation to be due to Taenia saginata. A review of the relevant literature of the last 20 years failed to find many similar cases, parasites, particularly Taenia being an exceptional direct cause of perforation. In the case reported, however, a direct cause/effect relation is highly probable.

Adult↗
PubMed1986

Diagnostic value of upper intestinal fiber endoscopy in primary small intestinal lymphoma. A prospective study by the Tunisian-French Intestinal Lymphoma Group.

To assess the diagnostic value of upper intestinal fiber endoscopy in primary small intestinal lymphomas observed in an underdeveloped Mediterranean country, the endoscopic records of 40 patients (Group A) offering histologic evidence of lymphoma were compared with those of 80 patients (Group B) displaying clinical findings of small intestinal disease, but who eventually proved to be free of lymphoma after a complete work-up. The endoscopic procedure reached the jejunum in 91% cases and was well tolerated with only one reversible complication. Five primary endoscopic patterns could be defined, occurring either alone or in various combinations. The infiltrated pattern was the most sensitive (0.80) and specific (0.96) finding with predictive positive and negative values reaching 0.88 and 0.93, followed by the nodular pattern (sensitivity 0.60, specificity 0.84). Other primary lesions (ulcerations, mosaic pattern, mucosal fold thickening alone) were either nonsensitive or nonspecific or both. The infiltrated pattern proved to be more valuable than any association of primary lesion. Per endoscopic biopsies were diagnostic of lymphoma in 85% cases. These findings strongly suggest that upper intestinal fiber endoscopy, using long ending view instruments should be the first investigation in patients suspected of small intestinal lymphoma in developing Mediterranean countries.

Adolescent↗
PubMed2004

Tissue-engineered small intestine improves recovery after massive small bowel resection.

OBJECTIVE: Rescue with tissue-engineered small intestine (TESI) after massive small bowel resection (MSBR). SUMMARY BACKGROUND DATA: Short bowel syndrome is a morbid product of massive small bowel resection. We report the first replacement of a vital organ by tissue engineering with TESI after MSBR. METHODS: Ten male Lewis rats underwent TESI implantation with green fluorescent protein (GFP)-marked cells (TESI+, n = 5) or sham laparotomy (TESI-, n = 5) followed by MSBR. Side-to-side anastomosis of TESI to proximal small intestine was performed or omitted. TESIO animals underwent implantation of engineered intestine with no further surgery. Weights were measured QOD until day 40. Transit times were measured. DNA assay was performed with computer morphometry. Northern blots of RNA were probed for intestinal alkaline phosphatase (IAP) and villin. Hematoxylin and eosin, S100, and smooth muscle actin immunohistochemistry were performed. Blood was collected at sacrifice. RESULTS: All 10 rats initially lost then regained weight. The initial rate of weight loss was higher in TESI+ versus TESI-, but the nadir was reached a week earlier with more rapid weight gain subsequently to 98% preoperative weight on day 40 in animals with engineered intestine versus 76% (P < 0.03). Serum B12 was higher at 439 pg/mL versus 195.4 pg/mL. IAP mRNA appeared greater in TESI+ than TESIO, with constant villin levels. Histology revealed appropriate architecture including nerve. GFP labeling persisted. CONCLUSIONS: Anastomosis of TESI significantly improved postoperative weight and B12 absorption after MSBR. IAP, a marker of differentiation in intestinal epithelium, is present in TESI, and GFP labeling was accomplished.

Actins↗
PubMed2001

Retention and transit of intestinal mucoadhesive films in rat small intestine.

The retention and transit characteristics of intestinal mucoadhesive film systems have been studied after intraduodenal administration in rats. Small size four layered film preparations, 0.5x0.5 mm, were prepared, where the backing layer (45.1+/-2.9 microm thick) was made of a water-insoluble polymer, ethylcellulose (EC), the surface layer was made of enteric pH-sensitive polymers, Eudragit L100, S100 or HP-55 and the middle layer was made of cellulose membrane. The surface layer was attached to the middle layer with an adhesive layer composed of carboxyvinyl polymer (Hiviswako(R) 103). After administration of ten films to the duodenum, the rats were sacrificed hourly and the distribution of the films in the whole small intestine was directly observed after abdominal incision. The HP-55, Eudragit L100 and S100 film systems were found to adhere to the upper, middle and lower part of the small intestine after 1, 2 and 4 h, respectively, for 2-3 h. Direct inspection study suggests that intestinal mucoadhesive film system has functions of: (1) pH-dependent intestinal adhesion site specificity; (2) adhesion to the intestinal wall; and (3) retention in the small intestinal adhesion site for at least 2 h. Intestinal mucoadhesive film system has been suggested to be a targeting system for drugs to the gastrointestinal tract.

Adhesiveness↗
PubMed1997

[Volvulus of the small intestine].

Volvulus of the small intestine is a condition of bowel obstruction due to knotting and twisting of the small intestine. Two types of volvulus are described: 1) primary small intestinal volvulus where no predisposing factors exist, and 2) secondary volvulus where congenital or acquired conditions promote twisting of the small intestine. Over a 5-year period, 18 patients (eleven men and seven women) presenting volvulus of the small intestine are operated in the Emergency Surgery Clinic of the University Hospital "Queen Giovanna", representing 8.7 per cent of the total of 206 cases of small intestinal mechanical ileus (incarcerated herniations involving the small intestine are not included in the series). Primary volvulus is found in one patient. In those presenting secondary volvulus adhesions are the commonest underlying cause of small intestinal rotation--13 cases, next ranking primary tumor of the small intestine--one case, Meckel's diverticulum--one, carcinosis of peritoneum--one, and one patient with small intestine volvulation around colostomy. The most frequently encountered symptoms and laboratory examinations performed are analyzed. Intestinal necrosis is established in four instances (22 per cent). One patient dies of peritonitis and polyorganic insufficiency. Volvulus of the small intestine should be mandatorily considered in patients presenting mechanical ileus of the small intestine. Early operative intervention is a therapeutic approach contributing to preclude intestinal necrosis.

Adult↗
PubMed1991

Small intestinal cytochromes P450.

Small intestinal cytochromes P450 (P450) provide the principal, initial source of biotransformation of ingested xenobiotics. The consequences of such biotransformation are detoxification by facilitating excretion, or toxification by bioactivation. P450s occur at highest concentrations in the duodenum, near the pylorus, and at decreasing concentrations distally--being lowest in the ileum. Highest concentrations occur from midvillus to villous tip, with little or none occurring in the crypts of Lieberkuehn. Microsomal P4503A, 2C8-10, and 2D6 forms have been identified in human small intestine, and P450s 2B1, possibly 2B2, 2A1, and 3A1/2 were located in endoplasmic reticulum of rodent small intestine, while P4502B4 has been purified to electrophoretic homogeneity from rabbit intestine. Some evidence indicates a differential distribution of P450 forms along the length of the small intestine and even along the villus. Rat intestinal P450s are inducible by xenobiotics--with phenobarbital (PB) inducing P4502B1, 3-methylcholanthrene (3-MC) inducing P4501A1, and dexamethasone inducing two forms of P4503A. Induction is most effectively achieved by oral administration of the agents, and is rapid--aryl hydrocarbon hydroxylase (AHH) was increased within 1 h of administration of, for example, 3-MC. AHH, 7-ethoxycoumarin O-deethylase (ECOD), and 7-ethoxyresorufin O-deethylase (EROD) have been used most frequently as substrates to characterize intestinal P450s. Dietary factors affect intestinal P450s markedly--iron restriction rapidly decreased intestinal P450 to beneath detectable values; selenium deficiency acted similarly but was less effective; Brussels sprouts increased intestinal AHH activity 9.8-fold, ECOD activity 3.2-fold, and P450 1.9-fold; fried meat and dietary fat significantly increased intestinal EROD activity; a vitamin A-deficient diet increased, and a vitamin A-rich diet decreased intestinal P450 activities; and excess cholesterol in the diet increased intestinal P450 activity. The role of intestinal P450 in toxifying or detoxifying specific xenobiotics has been clearly demonstrated to only a limited extent. However, elevated intestinal P450 levels have been indirectly linked to gastrointestinal cancer. Intestinal metabolism of 2,2,2-trifluoroethanol produces intestinal lesions with consequent systemic bacterial infection.

Animals↗
PubMed2026

Characterization of small intestinal neuroendocrine tumorlets.

Small intestine neuroendocrine tumors (SI-NETs) frequently present as multifocal primaries. We commonly observe microscopic lesions in the superficial layer of the small intestine of SI-NET patients. We aimed to define them as small intestinal neuroendocrine tumorlets (SINTs) and explore their clinical and biological significance. Twenty multifocal and twenty unifocal SI-NETs patients who received resection at a single institution were retrospectively reviewed. Four hundred and forty six archived pathological slides were examined for microscopic lesions located in the lamina propria, muscularis mucosa, and superficial submucosa. Clinicopathological associations and progression-free survival were analyzed. Previously published genomic data were re-analyzed. SINTs were identified in 50% of multifocal and 30% of unifocal SI-NET patients. Median SINT size was 95 &#x3bc;m, with a median distance of 2.2 mm from the nearest mass. Compared to the 'true unifocal' group (unifocal without SINT), the 'multifocal-spectrum' group (multifocal or unifocal with SINT) had higher BMI (median: 27.6 vs 22.8, P = 0.0060), higher rates of perineural invasion (OR: 5.5, P = 0.044), larger mesenteric mass (median: 2.6 vs 1.6 cm, P = 0.034), and more advanced pT stage (pT3 or pT4, OR: 7.2, P = 0.018). Genomic re-analysis suggested that 13% of cells in multifocal primary tumors could share clonal origins, possibly indicating clonal spread via SINTs. SINTs may serve as a new biomarker for multifocal spectrum with local aggressiveness. The actual frequency of multifocal SI-NET may be higher than currently recognized in clinical practice. Further studies are needed to validate their prognostic and biological significance.

Humans↗
PubMed1995

Effect of streptozotocin-induced diabetes mellitus on release of vasoactive intestinal polypeptide from rodent small intestine.

Representative longitudinal muscle strips (6 x 10 mm) from proximal and distal small intestine were excised from control and streptozotocin-treated rats after one month of untreated and insulin-treated diabetes. Untreated diabetes significantly reduced tissue concentrations of vasoactive intestinal polypeptide (VIP) at both intestinal loci. Insulin treatment of the diabetic animals restored tissue VIP concentrations to control group levels, although the beneficial effect of insulin treatment was only significant in the duodenum. Spontaneous release of VIP was significantly attenuated by untreated diabetes at both intestinal sites. In the duodenum, insulin treatment of the diabetic animals restored VIP release to levels indistinguishable from control group values. In the ileum, insulin treatment produced levels of VIP release that were not significantly different from those of the control and untreated diabetic groups. Tetrodotoxin (5 x 10(-6) M) significantly--but incompletely--inhibited VIP release from control group animals at both intestinal sites. These observations indicate that diabetes mellitus significantly diminishes VIP tissue concentrations and release from intestinal myenteric nerves. These abnormalities improve with insulin treatment. However, the mechanisms of VIP release from proximal and distal intestine appear to differ not only in their response to the diabetic state, but also in their response to insulin treatment.

Animals↗
PubMed1975

Changes in the intestinal lactase activity in the small intestine of two breeds of swine from birth to 6 weeks of age.

Total and specific lactase activities in the small intestine of Chester White and Hampshire pigs were measured at 1, 8, 15, 22, 29, and 43 days of age. The small intestine was divided into 10 segments of equal length, the proximal 10 cm of each segment was scraped, and the scrapings were homogenized for use in the lactase determinations. Significant breed, age, and segment differences were observed for both specific and total activities. In both breeds, the total lactase activity at 1 day of age was lower than that at any other age. After reaching maximal levels at 15 days of age, the total activity declined with the loss of activity occurring primarily in the ileum. At 1 and 8 days of age, the total lactase activities for the two breeds were similar, but the Chester White pigs had higher activities at all other ages. The pattern of changes in specific activity with age was similar for both breeds. The mean specific activity was highest at 1 and 8 days of age and then fell progressively to minimal levels at 43 days of age. Chester Whites had higher specific activities than Hampshires during the first 4 weeks of life, but at 6 weeks of age there was little difference between the breeds. The peak lactase activity, expressed as total or specific activity, occurred in the proximal one-third of the small intestine of both breeds, and the distal one-third of the gut had relatively low activities as the animals matured.

Age Factors↗
PubMed2003

Using porcine small intestinal submucosa in intestinal regeneration.

Small intestinal submucosa (SIS) is an unusual tissue that promotes constructive tissue remodeling when applied as a xenogeneic material. The aim of our experimental study was to assess its effectiveness in intestinal regeneration. Twenty white New Zealand rabbits were anesthetized and underwent celiotomy. A 6-cm antimesenteric incision was created at the jejunal segment. An elliptical SIS graft measuring 6 cm long and 2 cm wide was sutured to the jejunal defect as a patch graft. Thirteen living rabbits were divided into groups of three and the grafts were harvested at postoperative weeks 2, 4, and 6. The obtained specimens were evaluated for gross and histologic appearance. In morphometric examination, in the 2, 4, and 6 weeks groups, the diameters of grafted intestines were larger than preoperatively by 50%, 25%, and 25% respectively; also the grafts had contracted to 0%, 25%, and 50% of their original sizes respectively. At the end of 2 weeks, the grafts were intact without evidence of epithelial regeneration. By 4 weeks, intestinal tissue regeneration was started, and epithelial coverage of the grafts was detected. The grafts were covered with a complete intestinal mucosa at 6 weeks. Remarkable regeneration marked fibroplasia, angiogenesis, and mild mononuclear cell infiltration had also occurred throughout the grafts at 6 weeks. Porcine SIS appeared an effective biodegradable scaffold, facilitating regeneration of intestinal tissue. These results suggest that SIS may be useful to increase the mucosal surface of intestine and may provide a new substance for short gut syndrome in the future.

Animals↗
PubMedDate not supplied

Enhanced bone regeneration using porcine small intestinal submucosa.

Small intestinal submucosa (SIS) is an easily produced material that has been used experimentally for tissue engineering. To evaluate the ability of SIS to facilitate bone growth within a long-bone defect, a segment of the radius was surgically removed in adult, female Sprague-Dawley rats. The defect was either left unfilled or implanted with SIS, demineralized cortical bone (DMCB), or ovalbumin. The defect was evaluated radiographically and histologically after 3, 6, 12, and 24 weeks. Tissue remodeling within the defect was evident by week 3 in SIS- and DMCB-treated rats. Filling was characterized initially by infiltration of mononuclear cells and extracellular material in SIS-implanted rats and multifocal remodeling bone particles and cartilage formation in DMCB-implanted rats. Cartilage was observed as early as 3 weeks and bone as early as 6 weeks in SIS-implanted rats. Filling of the defect arose from multiple foci in DMCB-implanted rats, but was contiguous with and parallel to the ulnar shaft in SIS-implanted rats, suggesting that defect repair by SIS may be conductive rather than inductive. Rats in which the defect was left unfilled demonstrated slow but progressive filling of the defect, characterized by mononuclear cell infiltrates and fibrous extracellular material. In summary, SIS facilitated rapid filling of a long-bone defect. These results suggest that SIS may be useful as a bone repair material.

Animals↗