Effect of irradiation on morphology and motility of canine small intestine

Summers, Robert W.; Flatt, A.; Prihoda, M.; Mitros, Frank A.

doi:10.1007/bf01296667

Cited by 46 publications

(25 citation statements)

References 15 publications

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“…Experimental animal studies do not necessarily reflect the situation in humans undergoing highly fractionated RT. Usually, in animal studies radiation is given in one dose to the abdomen, resulting in profound motility changes (27). An increased incidence of giant colonic migrating contractions coinciding with episodes of diarrhoea is seen during fractionated radiation (28,29 Radiation-induced decrease in fecal bifidus excretion was reversed by oral application of L. acidophilus (32), and patients receiving oral L. acidophilus prophylaxis had reduced incidence of diarrhoea during pelvic RT (33).…”

Section: Discussionmentioning

confidence: 99%

Profiles and Time Course of Acute Radiation Toxicity Symptoms during Conformal Radiotherapy for Cancer of the Prostate

et al. 2003

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Section: Discussionmentioning

confidence: 99%

Profiles and Time Course of Acute Radiation Toxicity Symptoms during Conformal Radiotherapy for Cancer of the Prostate

et al. 2003

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“…These migrating clustered contractions are highly effective at propulsion [47] . Single dose radiation in a canine model [5] produced clusters of migrating ERA probably associated with these migrating clustered contractions.…”

Section: Migrating Clustered Contractionsmentioning

confidence: 99%

“…Neural and chemical stimulation may not be present during each depolarization of ECA, and thus contractions then do not occur at the maximum possible frequency (Figure 1). Recordings of gastrointestinal motility can either be made with devices that record physical contractions (manometry catheter or strain gauges) or motility can be implied from electrical activity or transit times.Single dose (938 Gy) in a canine model disrupted normal electrical patterns [5] . Jejunal myoelectric activity decreased in frequency, duration and length of migration o f E R A p o s t p r a n d i a l l y. E C A wa s i r r e g u l a r w i t h nonuniform morphology and occasionally migrated in an orad direction.…”

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Effects of radiation upon gastrointestinal motility

Otterson¹

2007

WJG

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neural and chemical control. Myogenic control refers to the electrical activity generated by the smooth muscle of the gut. Electrical control activity (ECA) [1][2][3][4] is the omnipresent rhythmic depolarization of the cell membranes of the smooth muscle of the small intestine. With neural or chemical stimulation, membrane depolarization exceeds an excitation threshold and a contraction results. The electrical correlate of a contraction is called electrical response activity (ERA) [1][2][3][4] . These bursts of electrical response activity have a 1:1 relationship with contractions. Because ERA occurs only during the depolarization phase of the ECA cycle, the frequency of contractions is limited to and determined by the frequency of ECA. Neural and chemical stimulation may not be present during each depolarization of ECA, and thus contractions then do not occur at the maximum possible frequency (Figure 1). Recordings of gastrointestinal motility can either be made with devices that record physical contractions (manometry catheter or strain gauges) or motility can be implied from electrical activity or transit times.Single dose (938 Gy) in a canine model disrupted normal electrical patterns [5] . Jejunal myoelectric activity decreased in frequency, duration and length of migration o f E R A p o s t p r a n d i a l l y. E C A wa s i r r e g u l a r w i t h nonuniform morphology and occasionally migrated in an orad direction. ECA was occasionally uncoupled; coupling is a phenomenon in which corresponding ECAs recorded from different areas maintain a consistent time shift [6] . In spite of these functional abnormalities, the histology was minimally altered. These changes in electrical activity suggest a profound change in the physiology of the smooth muscle as well as the nerves controlling the muscle.Gastrointestinal smooth muscle contractile activity can also be influenced by extrinsic autonomic (parasympathetic and sympathetic) from the CNS and the intrinsic neurons of the enteric ner vous system. The stomach, small intestine and proximal colon derive their parasympathetic innervation through the vagus nerve which contains both afferent and efferent fibers. Relative to the intrinsic enteric neurons, the efferent potion of the vagus is really quite small; however, each vagal efferent fiber may influence about 2000 enteric neurons [7,8] . The sensory component of the vagus nerve is much greater. Sensory fibers account for 80% of all vagal fibers [9] . Vagal afferents detect both the mechanical and chemical stimulation of the small intestine and relay this information centrally for processing. Sympathetic innervation of the intestine arises from the thoracic and lumbar spinal nerves. These �� Effects of radiation upon gastrointestinal motility AbstractWhether due to therapeutic or belligerent exposure, the gastrointestinal effects of irradiation produce symptoms dreaded by a majority of the population. Nausea, vomiting, diarrhea and abdominal cramping are hallmarks of the prodromal ph...

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“…Recent studies in humans have shown that following radiotherapy the rate of small intestinal transit is increased and may contribute to small intestinal malabsorption (5,6). Previous studies in animals which have utilised a single sub-lethal dose of radiation have shown that this is also associated with rapid intestinal transit (7). The motor mechanisms which underlie the accelerated small intestinal transit due to radiation entertis are poorly understood although in dogs, high amplitude propagated intestinal contractions were associated with fractionated radiotherapy (8).…”

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confidence: 99%