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Biomedical subjects

S Gustavsson

Publications and source records attributed to S Gustavsson.

124 records · Page 7Linked to original sources
PubMed1978

Distribution and metabolism of gastrin. An experimental study of the fate of 123 I-gastrin in the rat as studied by external detection with a gamma camera.

In anesthetized rats, the activity distribution of intravenously administered synthetic human gastrin I, labelled with 123 I, was recorded externally by a gamma camera. In intact rats activity was found to accumulate in the kidneys and later in the stomach. After bilateral nephrectomy, the gastric apperance of activity was delayed. In both cases, the gastric activity is considered to emanate not from intact 123 I-gastrin but from free iodide, split off during gastrin degradation. The renal accumulation of gastrin in intact animals as well as the delayed gastric uptade of iodide in nephrectomized animals support the hypothesis that the kidneys are important organs for gastrin metabolism.

Animals↗
PubMed1978

Propulsion and mixing of small bowel contents after laparotomy in rat.

Radioactive test substances were infused slowly into the duodenum of conscious rats via a permanent catheter starting 2, 12 and 24 h after a standardized laparotomy. Two differently labelled but otherwise identical test substances were used. The first test substance (125I-PVP) was infused for 4 h, the second (131I-PVP) for the remaining 1 h of the 5-hour infusion period. Immediately after the infusion the animals were killed, and the radioactivity emanating from each isotope was recorded from the excised bowel specimen. The bowel length passed by the border zone and the degree of overlap between the labels in this zone were taken as measures of propulsion and mixing, respectively. Propulsion and mixing were uninfluenced by laparotomy as measured 2--17, 12--17 and 24--29 h after laparotomy. The present findings indicate that laparotomy is not followed by a disturbance in the capability of the small bowel to transport and mix chyme, at least when no high demands with respect to chyme volume are required.

Animals↗
PubMed1978

Participation of antral somatostatin in the local regulation of gastrin release.

In anaesthetized pigs gastrin release was stimulated by irrigation of the antrum with bicarbonate and by instillation of a meat extract. The concentration of gastrin and somatostatin was measured by radioimmunoassay both in the antral and peripheral venous blood. The increase in gastrin was coupled to a significant decrease in somatostatin immunoreactivity as measured in the antral venous blood both during instillation of alkali and meat extract. In peripheral blood, the differences were much less evident and not statistically significant. It is speculated that the decrease in release of antral somatostatin during alkalinization and instillation of meat extract is the primary event which is followed by a diminished inhibition of gastrin liberation. Thus, the present data support the hypothesis that antral somatostatin participates in the local regulation of gastrin release.

Animals↗
PubMed1978

Studies on the transport of small bowel contents. An experimental study in the rat with special reference to the evaluation of non-propulsive intestinal movements.

An earlier study (4) of chyme propagation through the small bowel in conscious rats has revealed that the luminal contents are transported in separate portions, which exchange material only to a limited extent. In the present study this transport pattern was confirmed also after the following changes in the standardized experimental conditions used previously: (a) replacement of the standard radioactive labels (125I-PVP and 131I-PVP) with Na2(51CrO4) and 99Tcm-sulphur colloid, (b) replacement of the test meal with saline and (c) investigation of animals without a preceding starvation period. It was also found that the small bowel propulsion was enhanced when the test substance was infused at a higher rate, and that this change did not affect the exchange of material between the portions. The small mixing was further confirmed in experiments in which shifts of label were made repeatedly at constant intervals throughout the infusion period. Distinct regions in which one of the labels predominated could be demonstrated along the entire small bowel when the time interval was diminished to 30 but not to 20 min.

Animals↗
PubMed1978

Propulsion and mixing of small bowel contents during exogenous gastrin infusion. An experimental study in rat.

The effect of intravenous infusion of Synthetic Human Gastrin I (SHG) on the propulsion and mixing of small bowel contents was studied quantitatively in conscious rats. Radioactive test substances were infused continuously through a permanent duodenal catheter for totally five hours. Two differently labelled, but otherwise identical, test substances were used and one of them (125I-PVP) was infused during the first three hours, the other (131I-PVP) during the remaining two hours. The activity distribution of each isotope along the excised bowel specimen was measured immediately after the end of the infusion. The bowel length passed by the transition point between the nuclides and the region of overlap in the border zone between them were taken as measures of propulsion and mixing, respectively. A significant increase of the serum gastrin level during infusion of SHG was verified by radioimmunoassay. The total small bowel transit time was significantly prolonged during gastrin infusion secondary to a retarded propagation velocity in the distal small bowel. The slower transport rate during gastrin infusion was coupled to a significant increase of the mixing of small bowel contents. These changes in small bowel motility were not apparently due to a concomitant increase of gastrict acid secretion, since pretreatment with a potent H2-receptor blocker, cimetidine, did not abolish them.

Animals↗
PubMed1978

Propulsion and mixing of small bowel contents in rat during varied levels of endogenous gastrin.

The propulsion and mixing of small bowel contents were studied in conscious rats 14 days after antral resection, antral exclusion and gastroentero-anastomosis in order to evaluate the influence of hypo-, hyper- and normogastrinemia, respectively, on the net result of small bowel muscular activities. The quantitative measures of propulsion and mixing did not differ significantly between the groups. There was, however, a significant correlation between high serum gastrin and increased intestinal mixing after antral exclusion and gastroentero-anastomosis. This finding supports earlier studies on gastrin effects on the small bowel obtained by exogenous gastrin infusion.

Animals↗
PubMed1978

Gastric emptying in duodenal ulcer patients before and after truncal vagotomy with pyloroplasty and parietal cell vagotomy.

The gastric emptying of a liquid test meal containing 99Tcm-sulphur colloid was studied with a gamma camera in 24 duodenal ulcer patients. Studies were made before surgery, randomly chosen between truncal vagotomy with pyloroplasty and parietal cell vagotomy, and six weeks and one year after. Large variations in the emptying patterns were observed both between patients and in the same patients. No consistent change in the distribution of patterns were found between the three observation times and between the two surgical procedures. An initial rapid emptying was found in several studies and was observed both before and after operation and did not seem to be related to type of surgical procedure or to individual patients. The method applied did not allow a detailed study of this initial phase, which appears to be of a higher significance for the over-all emptying characteristics than the late exponential emptying, on which earlier investigators have been focused.

Adult↗
PubMed1977

Effects of vasoactive intestinal peptide and pancreatic polypeptide on small bowel propulsion in the rat.

Vasoactive intestinal peptide (VIP) and the newly discovered pancreatic polypeptide (PP), both having been proposed as pathogenetic factors in the watery diarrhea syndrome (WDRA), were intravenously infused into rats in order to study the effect on small bowel propulsion. Simultaneously with the infusion of hormone, radioactive test substance was continuously infused into the duodenum of the conscious animal through a permanent catheter. By recording the distribution of radioactivity along the excised gastrointestinal tract, analyses of small bowel propulsion were possible. After infusion of VIP small bowel transit time was significantly prolonged, and the local propagation velocity was retarded both in the proximal and the distal part of the small bowel. PP did not alter small bowel populations. The heavily retarded transport rate after VIP is a propulsive dysfunction and not inconsistent with the clinical sign of diarrhea.

Animals↗
PubMed1977

Simultaneous measurement of the propulsion and mixing of small bowel contents in the rat.

A method is presented for the simultaneous measurement of propulsion and mixing of small bowel contents in conscious rats. Through a permanent duodenal catheter two differently labeled test substances (125I-PVP and 131I-PVP) were infused continuously one after the other. The radioactive label was changed once during the total infusion period of 5 hours. Studies were performed in six groups of animals which differed with respect to time for interchange of test substance. At the end of the total infusion period the border zone had travelled to six different locations in the small bowel. The animals were then killed and the two radioactivities were recorded from the excised bowel specimen. The resulting activity densities along the small bowel were peaky and the overlap between the two labels in the border zone was minute, indicating that the intestinal contents were transported in isolated portions with only minor exchange of luminal contents between adjacent regions. The transport apparently proceeded steadily in a mainly aboral direction with no indications of abrupt changes in transport velocity.

Animals↗
PubMed1975

Analyses of small bowel propulsion, ileo-caecal passage and serum gastrin after truncal vagotomy. A methodological study in the rat with continuous intraduodenal infusion.

A test substance containing 51CrO--4 was administered to the duodenum of vagotomized or sham-operated, conscious rats for 5 hours at a rate of 3.3 mul/min. The distribution of 51Cr in the stomach, small bowel, caecum and colon was measured with a scintillation counter. Data reduction was made with automatic methods. The activity distribution in the small bowel was found to be irregular. A transit time of about 3 hours was observed between the duodenum and the caecum. The proximal 40% of the small bowel was passed in about 30 min at a constant rate. No differences between vaotomized animals and controls could be demonstrated. The passage from ileum to caecum in vagotomized animals indicated a process, with constant portions, each discharge containing about 11% of the total administered activity, implying two discharges per hour.

Animals↗
PubMedDate not supplied

Biliary excretion of olsalazine sodium in humans.

The biliary excretion of Olsalazine sodium (ADS) was studied by three different methods in healthy volunteers and in patients. 1 g ADS in a 2% solution was infused during 1 h into jejunum in six healthy volunteers via a three lumen sond. The bile was collected, during 2.5-6 h, proximal of an occlusive balloon on the three lumen sond. 10 mg ADS was given i.v. to five healthy volunteers and the bile was collected during 3-4.5 h with the same type of three lumen sond as used in the first experiment. 1 g ADS was given orally to three patients, with a T-tube inserted into coleducus at surgery. The bile was collected via the T-tube for 24 h. The mean biliary excretion of the jejunal dose was 0.41% (0.22% if one subject, who probably had a beckflow of the instillation fluid, is omitted). In patients, the mean excretion with bile of ADS was 0.35% and of ac-5-ASA 0.17%. Due to the short collection time after jejunal infusion and the probably incomplete collection of bile in both enteral studies the biliary excretion was estimated to be less than 2% as ADS and less than 1% as ac-5-ASA. The biliary excretion of an i.v. dose showed large individual variations (0.16-12.2%) which were not correlated to the length of the collection time. The total excretion was estimated to be less than 20% as ADS. No metabolites were detected after the i.v. dose.

Adult↗