Protection of the intestinal mucosa during ischaemia by intraluminal perfusion

Mirkovitch, V.; Menge, H.; Robinson, J. W. L.

doi:10.1007/bf01851184

Cited by 17 publications

(9 citation statements)

References 7 publications

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“…If the mucosa is partially protected by the presence of a glucose-containing buffer in the lumen during the ischaemia, this secretion is either reduced or abolished [25]. In the same way, Triton X-100 treatment leads to an abolition of the absorption of sodium and water, but it does not induce secretion.…”

Section: Discussionmentioning

confidence: 94%

“…In contrast, following treatment with Triton X-100, the number of mature enterocytes remaining on the sides of the villi is presumably sufficient to maintain active transport at a finite, albeit reduced level. An analogous situation arises when the mucosa is protected from the deleterious effect of ischaemia by introduction of a glucose-containing buffer into the lumen during the trauma; under such conditions, active transport in vitro and glucose absorption in vivo are both reduced but not abolished [25,31]. One other point is worth mentioning in this context, viz., that it has recently been deduced from experiments on rat intestine that any cells apparently intact on the sides of the villi after acute ischaemia may be functionless because of the depletion of their energy supplies during the ischaemic period [22]; such considerations would presumably not apply to intestines treated with Triton X-100.…”

Section: Discussionmentioning

confidence: 98%

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Source of net water and electrolyte loss following intestinal ischaemia

1980

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Ischaemia of the dog intestine lasting 1 h causes desquamation of the epithelium at the villus tips and congestion in the villus capillaries. The crypt cells are relatively undamaged. These changes are associated with a loss of active transport of organic solutes, determined in vitro, a reduction in mucosal sucrase activity and an abolition of glucose absorption in vivo. A profuse net loss of water and electrolytes into the lumen in vivo develops. The net sodium loss is due primarily to an inhibition of the lumen-blood flux of this ion, the blood-lumen flux being relatively unchanged. In uraemic dogs, the loss of urea into the lumen is the same in control and ischaemic loops, testifying to the lack of change in the unidirectional water flow from blood to lumen. Perfusion of the dog intestine with 1% Triton X-100 leads to morphological changes that have certain similarities with those provoked by ischaemia. Damage was restricted to the villus tips, protection from further alterations apparently being provided by a mucus layer that forms on the mucosal surface; the crypt region remained unchanged. After 10 min exposure, organic solute transport in vitro and glucose absorption in vivo were both reduced by not abolished; sodium and water absorption in vivo were suppressed, but no net secretion occurred. To account for these observations, we have suggested that the normal crypt cell is a secretory element with respect to sodium and water. During maturation, its absorptive properties develop such that the mature enterocyte, possessing both absorptive and secretory mechanisms, is capable of net absorption of sodium. After destruction of the villus tips, net secretion continues in the crypts; if there are insufficient villus cells remaining to ensure reabsorption, a net secretory capacity is observed.

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Section: Discussionmentioning

confidence: 94%

Section: Discussionmentioning

confidence: 98%

Source of net water and electrolyte loss following intestinal ischaemia

1980

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“…Finally, we have shown in previous stud ies [12,13,18] that the deleterious effects of ischaemia in the small intestine can be miti gated by intraluminal perfusion during the trauma, and have demonstrated that the oxy gen content of the luminal fluid is the most important factor in this protection. In the present work, we see that simply rinsing out the colon before the intervention has little effect on the functional status of the isch aemic organ; on the other hand, if the organ is perfused with an oxygenated buffer during the ischaemia, the functional capacity of the colonic mucosa is seen to be perfectly normal when determined in vitro 1 h after the end of the trauma (table II), though clearly, as pointed out above, much of the normaliza tion probably occurs during the post-ischaemic perfusion.…”

Section: Discussionmentioning

confidence: 99%

“…As in the small intestine ------------------------------------------------------ [12,19], the net absorption of water and elec trolytes across the normal mucosa is trans formed after this trauma into net loss across the ischaemic bowel. However, detailed ex amination of the functional characteristics of the two canine intestines gives rise to inter esting questions concerning the source of this fluid.…”

Section: Discussionmentioning

confidence: 99%

Functional Alterations in the Dog Colon Mucosa following Temporary Ischaemia

Mirkovitch¹,

Winistörfer²,

Robinson³

1982

Digestion

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Segments of dog colon were subjected to 1 h of total ischaemia. In one experimental group, the colon was not touched before the trauma; in another, it was rinsed out before the intervention; while in a third, it was perfused with Krebs bicarbonate buffer during injury. In all groups, the mucosa after the trauma is the site of net movement of water, sodium and chloride towards the lumen, while glucose absorption is greatly reduced. The accumulation of amino acid and sugar in vitro by samples of ischaemic mucosa is reduced but not abolished. The capacity for organic solute transport in vitro is greater in samples removed after the perfusion than in specimens excised immediately after the end of the ischaemia. According to the test in vitro, the mucosa can be protected from the deleterious effects of the ischaemia by intraluminal perfusion during the ischaemia. Immediately after 1 h of ischaemia, slight alterations in the histological structure of some villi were observed under the light microscope in occasional animals, particularly when the colon was not rinsed out before the ischaemia.

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“…was used and the duodenum was perfused with isotonic NaHCO3. The In the dog, severe mucosal desquamation occurs after an ischaemia of 1 hr, but the effects can be mitigated by intraluminal perfusion during the ischaemic period (Mirkovitch, Menge & Robinson, 1975). One of the factors aiding in this protection is the oxygen content of the perfusate (Robinson & Mirkovitch, 1977).…”

Section: Pmentioning

confidence: 99%

Communications

1981

The Journal of Physiology

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PHYSIOLOGICAL SOCIETY, JUNE 1981 is brought into focus. With video-image analysis and stage-stepping motors under computer control it is possible to focus automatically. Coleman, Garvey, Young & Simon (1977) developed an auto-focus for Golgi material which selected the position of darkest image. However, we have found it more appropriate to use the position of maximum smoothed-edge contrast for less-densely or less-uniformly stained neurones, e.g. those injected with Procion Yellow or HRP. The auto-focus described here was designed to allow the operator to concentrate fully on the location and classification of structures in the (XY) image plane and on error correction. As a bonus, it was found to be faster and more reliable than manual focusing.The Magiscan (Joyce Loebl) was used to analyse the video image automatically and to control the microscope stage. A high-power ( x 50) objective was used to sharpen the focus plane. Each neuronal structure was traced in the XY plane with a sequence of point pairs, either by automatic edge-tracing or manually with a light pen. A four pixel (approximately 0 7 jsm) square was centred on each of these two reference points. Grey levels from the sixteen outermost points of each square were used to estimate smoothed-edge contrast; the degree of focus was defined as the sum of the two maximum values obtained when adding grey levels from each four successive points along the edges of the two squares and subtracting those from the next four points. The video image was analysed at sixty-four levels of grey. At this sensitivity the noise in our standard Bosch camera resulted in fluctuations in grey readings of up to + 2 levels. The resulting variability in Z estimates was reduced to within ± 1 ,um step by adding results from two (25 Hz) video scans and smoothing the degree-of-focus curve (adding results from each three successive focus positions). The stability and sensitivity of this final measure was such that a fast adaptive scanning procedure could be used, mimicking manual focusing; instead oftesting over a relatively wide fixed range, the upward and downward movements were each stopped as soon as the focus measure was less than 98 % ofits maximum value (usually within 3 ,um steps).Supported by the M.R.C. REFERENCE COLEMAN, P. D., GARVEY, C. F., YOUNG, J. H. & SIMON, W. (1977 The results for the different anaesthetics showed trends in which the hydrocarbons lay at one extreme and the alcohols at the other. At concentrations which suppressed the Na current (at the potential ofits peak under control conditions) by approximately 50 %, the hydrocarbons moved the mid-point of the steady state inactivation (hz) curve and the peak of the inactivation time constant (Th) by ca. 15 mV in the hyperpolarizing direction. n-Pentanol, n-octanol and n-C8H17(0. CH2CH2)30H, by contrast, produced shifts (in the same direction) of less than 1 to 2 mV. The effects of the hydrocarbons and alcohols on the mid-point of the steady state activation (moo) curve on the peak of the activation time ...

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Protection of the intestinal mucosa during ischaemia by intraluminal perfusion

Cited by 17 publications

References 7 publications

Source of net water and electrolyte loss following intestinal ischaemia

Source of net water and electrolyte loss following intestinal ischaemia

Functional Alterations in the Dog Colon Mucosa following Temporary Ischaemia

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