PubMed Health⌕ Search

Biomedical subjects

B Thjodleifsson

Publications and source records attributed to B Thjodleifsson.

At least 19 recordsLinked to original sources
PubMed1991

Prevalence of iron deficiency and iron overload in the adult Icelandic population.

The aim of this cross-sectional study was to estimate the prevalence of iron deficiency and overload in the adult population in Iceland, a developed Scandinavian country. The study population consisted of 4240 individuals aged 25-74 years randomly selected from the national roster. Basic hematological, S-iron, S-total iron binding capacity (TIBC), and S-ferritin measurements were obtained on 2588 individuals (61.0%). The results indicated unusually large iron stores in the adult Icelandic population and significantly larger iron stores in the rural compared to the urban population. Iron deficiency was rare except in urban premenopausal women, where 1 in 4 showed evidence of iron deficiency and 3.2% had iron deficiency anemia. Seven patients with hereditary hemochromatosis were identified from a subgroup of 1887 subjects, resulting in a prevalence of 0.37%. Two of the hereditary hemochromatosis patients had been gastrectomized. Measures to improve the iron balance in urban premenopausal women cannot therefore include increased iron fortification of food but must be more directed towards the target group.

Adult↗
PubMed1990

Endoscopic findings in the stomach and duodenum after treatment with enteric-coated and plain naproxen tablets in healthy subjects.

To compare the damaging effect of enteric-coated and plain naproxen tablets on the gastric and duodenal mucosa, 12 healthy subjects were studied before and after 2 7-day treatment periods in a randomized, double-blind, double-dummy, crossover trial. Both preparations of the drug caused mucosal lesions, but the extent of the damage was significantly less in the stomach and duodenum after enteric-coated than after plain naproxen tablets. The subjects, however, did not have a preference for either preparation. The morning plasma naproxen concentration was significantly higher after treatment with enteric-coated naproxen than after treatment with plain tablets. The results of the study indicate that naproxen damages the mucosa of the stomach and duodenum through local and systemic effects. The local effect seems to be the more important and can at least be partially prevented by enteric-coating of the tablets.

Adult↗
PubMed1977

Outcome of sub-total thyroidectomy for thyrotoxicosis in Iceland and Northeast Scotland.

A comparative study of the outcome of surgical treatment for thyrotoxicosis was carried out in two countries with dissimilar dietary iodine levels. In the area with a high iodine level (Iceland) the prevalence of post-operative hypothyroidism was five times lower, but recurrent hyperthyroidism was five times higher, than in the area with lower iodine levels (northeast Scotland). The total morbidity reached comparable levels in the two samples. The prevalence of positive thyroid antibody tests and serum thyrotrophin levels was lower and the functional capacity of the thyroid remnant higher in the area with the higher dietary iodine intake. The study provides further evidence that there are important regional differences in the prevalence of factors known to influence the response to surgical treatment of thyrotoxicosis which should be taken into account when planning treatment services.

Adult↗
PubMed1977

Thyroid function in normal subjects in Iceland and Northeast Scotland.

A comparative study was made of thyroid function in samples of 'well' subjects, from separate geographical areas with dissimilar dietary iodine levels. In the area with the higher iodine level, Iceland, the prevalence of positive thyroid antibody tests and serum thyrotrophin levels were lower, while the capacity of the thyroid to respond to exogenous thyrotrophin was higher than in NE Scotland, an area with lower iodine levels. In contrast the prevalence of positive tests for another organ-specific antibody, gastric parietal cell antibody, was higher in Iceland. These observations are consistent with the reported differences in the incidence rates for thyrotoxicosis and gastric carcinoma in the areas studied. The results are in agreement with our findings in two groups of post-thyroidectomy patients from the same populations. This study provides support for the view that differences in the prevalence of constitutional and environmental factors in different populations contribute to the variation in reported outcome of treatment for thyroid disease.

Autoantibodies↗
PubMed1977

Assessment of the plasma disappearance of cholyl'l14C-glycine as a test of hepatocellular disease.

The plasma disappearance of a tracer dose of cholyl-l14C-glycine has been examined in 12 control subjects and in 32 patients with hepatocellular dysfunction. Simple analysis of the data did not detect hepatic dysfunction except in severe hepatocellular disease. The greatest degree of discrimination between normal subjects and patients with mild liver disease was obtained by taking the ratio of the plasma retention at 60 minutes to that at 10 minutes; it was similar to that obtained with serum gamma-glutamyl transferase. The two hour post-prandial plasma "total" bile acid concentration gave complete separation between the control subjects and patients with liver disease.

Adult↗
PubMed1977

Back-diffusion--fact or fiction?

Alterations in the concentration of acid in gastric juice secreted at different flow rates and disappearance of acid from the gastric lumen, when the gastric mucosa is exposed to acid luminal contents, have been interpreted as indicating "back-diffusion" of acid into the gastric mucosa from the luminal contents. The loss of acid from the gastric contents increases when the mucosa is exposed to certain drugs or is diseased, giving rise to the suggestion that the increased degree of "back-diffusion" of acid indicates mucosal damage, reflecting a breakdown of the gastric mucosal "barrier" to back-diffusion of acid from the gastric lumen. The change in the "barrier" properties of the gastric mucosa has been found to be associated with change in the electrical properties of the mucosa, so that alterations of the transmucosal potential difference has been considered to denote gastric mucosal damage. The case for every one of these hypotheses and for their underlying assumptions is discussed and found wanting for lack of direct evidence.

Animals↗
PubMed1976

Effect of intraduodenal magnesium sulphate on pancreas and gallbladder of man.

Magnesium sulphate has previously been used as a purgative in a test involving the measurement of the faecal excretion of pancreatic enzymes. In order to validate the use of magnesium sulphate for this purpose, in 18 individuals the pancreatic and biliary response to intravenous infusion of secretin (1 CU/kg-h) plus CCK(1IU/kg-h) were compared with the responses to one of three dose-rates of magnesium sulphate infused into the duodenum. The effect of magnesium sulhphate was also studied during the coincident intravenous administration of the hormones. Intraduodenal magnesium sulphate did not stimulate the secretion of bicarbonate into the duodenum but did evoke the secretion of pancreatic enzymes and discharge of bile. The pancreatic response to the exogenous hormones was not altered by coincident intraduodenal infusion of magnesium sulphate. We conclude that magnesium sulphate is a satisfactory purgative for speeding the intestinal transit of pancreatic enzymes.

Bicarbonates↗
PubMed1976

Response to jejunal acidification in man. I. Changes in composition of perfusate.

The jejunal disposal of perfused acid was studied in 11 control subjects and 12 patients with duodenal ulcer. It was found that the capacity to dispose of acid was saturable and was less than control in patients with duodenal ulcer. When the load of acid was small, all the acid disappeared from the jejunum and sodium bicarbonate could be aspirated. During acid perfusion there was secretion of water and electrolytes into the jejunum if the load of acid exceeded the dissipative capacity. Superimposed intravenous infusion of secretin and cholecystokinin increased acid disposal, particularly in patients with duodenal ulcer, and increased the associated rate of secretion of water and electrolytes or changed net absorption to net secretion. We conclude, firstly, that acid is removed from the jejunum by secreted bicarbonate, and secondly that the whole of the upper small intestine of patients with duodenal ulcer is functionally abnormal.

Bicarbonates↗
PubMed1976

Response to pentagastrin in Man. IV. Dose-response characteristics.

An analysis has been made of the gastric response of 7 individuals to a set of 5 dose rates of pentagastrin, given on different days or in sequence on the same day, in order to identify constraints on the use of secretory data in determining 'kinetic constants', such as ED50 or CMR. It has been shown that errors arise from the use of near-threshold doses of pentagastrin; too short periods of stimulation, and variant responses to pentagastrin. We conclude that values of ED50 are best considered as only qualitative, rather than quantitative, indices of sensitivity to pentagastrin.

Dose-Response Relationship, Drug↗
PubMed1976

Response to jejunal acidification in man. II. Pancreatic, biliary and gastric responses.

The effect of perfusion of the jejunum with acid on the secretion of bicarbonate, trypsin, and bile into the duodenum has been studied in 10 patients with duodenal ulcer and 8 control subjects and compared with the responses to intravenous infusion of secretin and cholecystokinin-pancreozymin (CCK). Both the secretion of bicarbonate and of trypsin into the duodenum were inversely related to the amount of acid dissipated during jejunal transit, so that if all the acid disappeared during transit of a 30-cm segment of jejunum, the pancreas did not secrete. In both groups of subjects, jejunal acidification elicited a relatively greater secretion of bicarbonate than secretion of trypsin or bile into the duodenum, compared with the response to the exogenous hormones. Jejunal acidification also inhibited the secretion of trypsin in response to concurrently administered exogenous hormones by the control subjects but not in patients with duodenal ulcer. We conclude taht the pancreatic response to acid in the human duodenum depends on exposure of the jejunal mucosa to the amounts of acid which are greater than (quite high, but variable) threshold in all subjects. Under the conditions of this study, patients with duodenal ulcer differed from control in lacking an acid-released jejunal inhibitor of the secretion of trypsin by the pancreas.

Bicarbonates↗
PubMed1975

Gastric function in chronic renal failure. Effects of maintenance haemodialysis.

40 patients with chronic renal failure have been studied in order to determine why some patients with azotaemia have previously been reported to secrete abnormally large amounts of acid and some to secrete very little. 15 of the 40 patients were undergoing regular haemodialysis, while the remaining 25 patients had not been so treated. 10 of the 25 non-dialysed patients had much-impaired capacity to secrete acid. The impaired gastric secretory capacity was corrected and became abnormally great after some months of regular haemodialysis in 4 patients. Regular haemodialysis, by removing factors responsible for the gastric mucosal damage, permits manifestations of an underlying gastric hypersecretory state.

Creatinine↗
PubMed1975

Effects of metiamide on the human stomach.

1. The effect of metiamide on gastric acidity in man has been studied. Solutions of hydrochloric acid or glucose were instilled into the stomach and the subsequent rates of gastric secretion and emptying, and the disappearance of acid within the stomach, were measured. 2. Metiamide inhibited the gastric secretory response to the instilled acid and glucose solutions but did not change the overall pattern of emptying of the instilled solutions. 3. During administration of metiamide, there was a net loss of acid from within the gastric lumen. The rate of disappearance of acid from the instilled acid solution was small and not sufficient in magnitude to account for the metiamide-evoked decrease in the concentration of acid secreted in response to pentagastrin. 4. We conclude that metiamide does not inhibit gastric secretion by altering the 'barrier' function of the gastric mucosa.

Bile Pigments↗
PubMed1975

A study of Graves' disease in Iceland.

The incidence of Graves' disease and its response to treatment have been studied in Iceland, where the main environmental factor possibly affecting Graves' disease is a high iodine intake. The incidence was found to be similar or lower to that reported for Europe. The response to treatment with drugs and radioiodine does not differ from that found in other countries but recurrent hyperthyroidism after subtotal thyroidectomy is more common in Iceland.

Environmental Health↗
PubMed1975

Effect of metiamide on the response to secretin and cholecystokinin in man.

The effects of intravenous metiamide on the pancreatic exocrine response to intravenous infusion of secretin plus cholecystokinin has been studied in eight patients with duodenal ulceration. The secretion of bicarbonate and water was not altered by metiamide. The secretion of enzymes was significantly less than control during infusion of metiamide. The differences between the pancreatic and gastric responses to metiamide are discussed.

Bicarbonates↗
PubMed1975

Aspects of the effect of metiamide on pentagastrin-stimulated and basal gastric secretion of acid and pepsin in man.

This study has examined the inhibition produced by metiamide on the gastric secretion of acid and pepsin in 13 patients with duodenal and three with gastric ulcer. The effect of metiamide on the response to a range of doses of pentagastrin in three normal individuals was determined, as was the interaction of metiamide and atropine on prolonged basal secretion. Metiamide inhibited the secretion of acid more than pepsin and the gastric secretion of patients with gastric ulcer more than duodenal ulcer. Metiamide inhibited both the maximal secretory response attainable with pentagastrin and decreased the sensitivity to pentagastrin. Atropine augmented and prolonged the action of metiamide.

Atropine↗
PubMed1975

Effects of long-term treatment with metiamide.

Metiamide was given to patients with peptic ulcer or oesophagitis in a pilot study to establish the therapeutic value of the drug. Administration of metiamide resulted in relief of pain within a week in the majority of patients. Healing of duodenal and gastric ulcers was observed.

Duodenal Ulcer↗