Water and electrolyte absorption in the gastrointestinal tract

Absorption of water and electrolytes in the gastrointestinal tract are dynamic processes which are closely coupled to each other. The luminal surface of the small intestine is so organized that the surface area available for contact with the intestinal contents is greatly amplified. Water is absorbed passively throughout the GI tract in response to osmotic pressure gradients set up by absorption of solutes, mainly that of sodium chloride, glucose, and amino acids. Sodium may be actively or passively absorbed. In the jejunuma Na+, K+, and Cl- are absorbed mainly by passive solvent drag or convection. In the ileum active absorption of sodium occurs. The soduim absorbed into the cell is actively pumped into the intercellular space by the basolateral membrane Na+ pump. The human colon is responsible for the final modification of the 500-1000 mls of fluid that enter it daily. This fluid is isotonic whith plasma in Na+ concentration. Approximately 80 - 90 percent of the water and more than 90 percent of the Na+ and Cl- that enter the colon daily are absorbed. Several pathological conditions and mechanisms that may result in net fluid and electrolyte secretion have also been discussed (Summary)

Endoscopic and gastric acid studies in homozygous sickle cell disease and upper abdominal pain

Upper endoscopic and gastric acid output studies were done in 51 patients with homozygous sickle cell (SS) disease and recurrent epigastric pain. Twenty (39 percent) had abnormalities in the upper gastrointestinal tract including 18 (35 percent) with peptic ulcers. Mean bassal and maximum acid output were similar in patients with and without duodenal ulcer (DU). Because DU in SS disease does not appear to be associated with high acid outputs observed in other populations, it may reflect reduced mucosal resistance, possibly resulting from ischaemia. This hypothesis was supported by the significantly lower fetal haemoglobin level among SS-DU patients. (Summary)

Endoscopic and gastric acid studies in homozygous sickle-cell disease and upper abdominal pain - abstract

Patients with homozygous sickle-cell disease frequently experience recurrent upper abdominal pain, the cause of which usually remains unknown. In order to determine the frequency of peptic ulcer disease, upper endoscopic and gastric acid studies were performed in 51 patients with homozygous sickle-cell (SS) disease and recurrent epigastric pain. Twenty (39 percent) had abnormalities in the upper gastrointestinal tract of which 18 (35 percent) had peptic ulcers. The clinical features were similar between patients with ulcers and those with a normal upper gastrointestinal tract. Mean basal and maximum acid output were similar in patients with and those without a duodenal ulcer (DU). Acid output in 15 haematologically normal patients with DU was significantly greater than in those with sickle-cell disease. Since duodenal ulceration in SS disease does not appear to be associated with the high acid output observed in other populations, it may reflect reduced mucosal resistance; this could result from ischaemia. This hypothesis was supported by finding significantly lower foetal haemoglobin levels in SS-DU patients (3.6 percent) than in SS controls (5.7 percent) (AU)

Does the "Dumping Syndrome" occur in Jamaicans?

In order to test whether the "dumping" syndrome occurs in Jamaicans after gastric surgery, we studied 48 patients and six normal volunteers. Subjective assessment and objective testing were carried out after a standard hypertonic (provocative) glucose meal. Serial packed cell volume estimations were carried out, and the percentage fall in plasma volume (an indication of dumping) was calculated from a standard equation. Forty percent of patients reported symptoms of dumping after gastric surgery, and even more (55 percent) had a significant fall in plasma volume. The syndrome occured most commonly after gastric resection or a drainage procedure, and was least prevalent after the operation of highly selective vagotomy (AU)

Experience with sham-feeding as a postoperative test of vagotomy

Sixty-six sham-feeding tests by the chew-and-spit method, using a standard weight hamburger as a test meal, have been carried out on 38 patients and 12 controls. Twenty-four of these were done before surgery for chronic duodenal ulcer, twenty-three, 3 months after surgery and seven, 1 year after the operation. In addition, a group of twelve persons without gastrointestinal symptoms was tested in a similar fashion as controls. One hundred and three insulin tests were carried out at various intervals after surgery on fifty duodenal ulcer patients. After surgery, a similar reduction in basal acid output (BAO) was observed in both sham-fed and insulin groups. Two of the twelve controls and two patients out of the twenty-four in the pre-op. group had a minimal response to the sham-feeding and another two actually had inhibition of secretion, suggesting that perhaps hamburger was not the best meal of choice for these individuals. Apart from the problems of using a meal of choice for each individual in sham-feeding, this test gives the same information as the insulin test and, because it is safer and more physiological, we would recommend its use (AU)

Experience with "Sham" feeding as a test of gastric secretion - abstract

Sham feeding by the "chew and spit" method using a hamburger has been carried out on 17 patients with chronic duodenal ulcer before surgery, 20 three months after surgery and 6 one year after surgery. A group of 11 unmatched controls was tested in a similar fashion. The insulin test was carried out at various intervals after surgery on 50 duodenal ulcer patients. The surgery significantly reduced basal acid output (BAO). However, after surgery (as was to be expected), BAO was similar in both the sham fed and insulin groups. Two out of 11 controls and two out of the 17 pre-op group had a minimal response to the sham feeding and another 2 actually had inhibition of secretion, suggesting that perhaps hamburger was not the best choice of meal for these individuals. Apart from the problems of choice of meal in sham feeding, because this test gives the same information as the insulin test and because it is safer and more physiological, we would recommend its use (AU)

Highly selective vagotomy for chronic duodenal ulcer: a clinical report

Early clinical results of Highly Selective Vagotomy in 20 patients with chronic duodenal ulcer have been described. Eight of these patients also had pyloro-duodenal obstruction. Is is concluded tha HSV produces early symptomatic improvement as evidenced by complete relief of pain in 18 of our 20 patients who had this operation. Complete vagotomy and a low morbidity rate are achieved by this procedure. Patients with pyloro-duodenal obstruction had complications in the post-operative period. Duodenal ulcer patients with severe symptoms should be offered HSV early before they develop pyloric stenosis.(AU)

Highly selective vagotomy for chronic duodenal ulcer: results of gastric acid secretion studies

The augmented histamine test (AHT) and the Hollander single criterion test have been carried out in patients who have been treated with highly selective vagotomy (HSV) for chronic duodenal ulcer. The HSV reduced basal acid output and maximum acid output by 50 to 70 percent at eight days after the operation comparedwith pre-operative levels. This reduction was maintained at three months. The Hollander test indicated that the vagotomy was inadequate in nineteen out of twenty patients (AU)

Highly selective vagotomy for chronic duodenal ulcer in Jamaicans - abstract

Twenty consecutive patients with chronic duodenal ulcer were treated by Highly Selective Vagotomy (HSV) at the University Hospital of the West Indies since June, 1979. Eight had clinical and radiological pyloric stenosis. Their age ranged from 23 to 65 years. There were 15 males and 5 females. All were of African extraction. Gastric acid studies were done on all patients pre-operatively and at 8 days post-operative. In 12 cases the test was repeated. Three months after surgery. At eight days post-operatively, there was a significant reduction in acid secretion: basal acid output 53 percentñ113, peak acid output 61 percentñ7, maximal acid output 65 percent5. There was no change between eight days and three months post operatively. Post-operative Hollunder (insulin) test at 8 days and 3 months showed that the vagotomy was complete. At three to seven months follow up, 90 percent patients were found to be symptom free (Visick I), by the surgeon. One patient reported partial relief of pain which required some dietary restraint (Visick II), another who had pre-operative pyloric stenosis improved but developed post-prandial fullness and occasional vomiting (Visick III). There was no mortality and no serious side-effects due to the HSV. However, two patients with pyloric stenosis had reoperation and gastroenterostomy for the relief of gastric stasis. Nineteen patients had gained weight at 3 months (mean 4.6 Kg), and regarded the operation as "very good". We have confirmed that HSV produces adequate reduction in gastric acid output and complete parietal cell denervation. This was sufficient to produce complete relief of duodenal ulcer symptoms in 18/20 (90 percent) of Jamaicans. Better results of HSV were seen when there was no pre-existent pyloroduodenal obstruction. Duodenal ulcer patients with severe symptoms should be offered HSV early before stenosis occurs (AU)

The ankle jerk in severe protein energy malnutrition (PEM) - abstract

Although muscular atrophy is a cardinal feature of severe PEM, there are little data on neuromuscular function. We therefore measured the ankle jerk in 16 severely malnourished children (age range 6 - 60 months, median 11.5 months) on admission, daily for the first week and then weekly until discharge. The results were compared with those from 9 healthy Jamaican children (age range 5 - 28 months median 14 months). The angle jerk was elicited by electrically stimulating the sciatic nerve in the popliteal fossa. Movement of the foot was recorded on an oscilloscope via a transducer attached to the left great toe. Measurement of latency period, contraction, plateau and relaxation times were made from photographs of the oscilloscope tracings. At all times and with all variables, the malnourished children had a wide range of measurements. Compared with the controls, there was no difference in the latency period (26ñ5 msecs vs 25ñ3). The contraction time was significantly slower on admission (162ñ10 msecs vs 130ñ5) but at 30 days post admission was significantly faster (106ñ4 msecs vs 130ñ5 msecs). The relaxation times showed a tendency to be slower on admission and faster after recovery but the differences were significant. The plateau time was also of a similar pattern with the recovery value being significantly shorter (33ñ3 msecs vs 46ñ4 msecs). Thus in all variables, on admission, there was a wide range with the times being slower than normal attaining normality at about 2 weeks after admission and thereafter being faster. In 3 children tested 1 month after discharge the angle jerk remained faster than controls. Thyroid function tests were all normal. The fact that the latency period was unchanged suggests that these changes are distal to the sarcoplasmic reticulum. They may be related to the supply of energy to the muscles during rapid growth or to the order in which the different muscle fibre types are repleted during recovery from severe PEM (AU)

Light microscopic and ultrastructural changes of the exocrine pancreas in magnesium deficient rats

In magnesium deficient rats with a clinical picture of protein malnutrition, pancreatic changes typical of protein malnutrition were expected. However, in rats fed for four weeks on a low magnesium diet (protein content 25 percent), light and electron microscopic studies revealed that the ascinar cells of the pancreas were packed with zymogen granules, suggesting a disturbance in the discharge (rather than in the production) of the pancreatic enzymes. The mitochondria and the lumina of the RER were swollen. The nuclei had an irregular outline, the chromatin was aggregated into irregular granules and the nucleolemma of the nucleolus was fibrillar. It was suggested that the disturbance in the release of pancreatic enzymes might cause a maldigestion of the dietary protein, which eventually would lead to the condition of protein malnutrition in the magnesium deficient rats. The disturbance of exocytosis in the pancreas of magnesium deficient rats might be due to the preferential use of all the available magnesium for protein (enzymes) synthesis so that there were no magnesium ions left for the energy dependent discharge of the zymogen granules (AU).

In vivo studies of amino acid, water and electrolyte transport in the small intestine of normal and magnesium depleted rats

Net amino acid, water and electrolyte transport from the small intestine in vivo was studied in normal and magnesium depleted rats, by a single pass perfusion technique. The net absorption of the amino acids, alanine and lysine increased with increasing concentration of the amino acid in the perfusion solution, within the concentration range studied (10 and 50mM). In all cases alanine was absorbed faster than lysine. Dietary magnesium depletion, lasting for a period of twenty eight days did not affect the net rate of transport of these two amino acids in any of the regions of the small intestine which were studied. In general, the presence of amino acids increased the absorption of water by comparison with that from saline. However, lysine at a concentration of 50mM tended to inhibit water absorption by comparison with that observed in the presence of alanine at 50mM. Magnesium depletion did not in general affect net transport rates of water in the presence and absence of amino acids. However, when alanine at a concentration of 50mM was perfused, water absorption was inhibited in the magnesium depleted rats. The presence of amino acids did not affect the transport of sodium in any of the regions of the small intestine. However, magnesium depletion did severely inhibit sodium transport, especially in the presence of alanine at a concentration of 50mM in all three regions of the small intestine. Amino acids stimulated the absorption of chloride by all segments of the small intestine by comparison with that from saline alone. Magnesium depletion however, significantly reduced chloride ion absorption by all three segments. Good correlations were found between the transport rates of sodium and chloride, sodium and water, and total solute and water in all three regions of the small intestine (AU)