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Biomedical subjects

J Ringstad

Publications and source records attributed to J Ringstad.

12 recordsLinked to original sources
PubMed1991

Rapidly fatal Addison's disease: three case reports.

Recently, three young individuals died unexpectedly outside hospital. Their past medical histories revealed complaints of weakness, anorexia and nausea, none of which had led to adequate medical examination. The present paper calls for vigilance when patients present with non-specific manifestations such as anorexia and weakness. Autopsies confirmed that the deaths were caused by adrenalitis, a diagnosis unsuspected at the time of death. The value of different post-mortem laboratory findings is discussed.

Addison Disease↗
PubMed1991

High serum selenium concentrations in reindeer breeding Lappish men.

This study investigated the relationship of serum selenium to its dietary sources in a group of Lappish men and a control population. Lappish men had higher serum selenium concentrations than non-Lappish men (1.79 vs 1.58 mumol/1; p = 0.003). Serum selenium correlated positively with consumption of reindeer meat, age and cholesterol. In linear regression models, however, being Lappish was the most significant predictor of high serum selenium. Lappish men ate more reindeer meat (p = 0.001) and less fish (p = 0.013) than men in the control group. Consumption of reindeer meat was also correlated with higher serum cholesterol levels. We conclude that high serum selenium concentrations in Lappish men may be important since low mortality from cancer is reported in this group.

Adult↗
PubMed1990

Selenium concentrations in the human thyroid gland.

Recently, we found that prediagnostic serum selenium concentration was significantly lower for cases developing thyroid cancer (n = 43) than for controls. We assumed that redistribution of serum selenium into the affected tissue took place in the prediagnostic period. The present study was carried out to determine the physiological concentration of selenium in the thyroid, since very few data are available in the literature. The concentrations of selenium in the thyroid (n = 45) and liver samples from Norwegians who had died because of acute illness or accidents were determined by hydride generation atomic absorption spectrometry. The mean selenium concentration was found to be 0.72 +/- 0.44 microgram/g in the thyroid and 0.45 +/- 0.11 microgram/g in the liver tissue. The surprisingly high concentration of selenium in apparently normal thyroids indicates that selenium has important functions in this organ. The remarkably broad range, together with the observation that no significant correlation exists between thyroid and liver concentrations, suggest that factors other than the selenium status are important determinants for the selenium concentration in the thyroid gland. This observation is consistent with our hypothesis that in carcinogenesis, prediagnostic processes influence the serum-/thyroid-ratio of selenium.

Adult↗
PubMed1988

Selenium deficiency and cardiac electrophysiological and mechanical function in the rat.

Earlier studies have shown that selenium and vitamin E are important in maintaining normal cardiac function. The present study was designed to test the effect of sole selenium deficiency on electrophysiological and mechanical characteristics of the rat heart. Male weanling rats were fed a standardized vitamin E adequate but selenium deficient diet, or a control diet. Deficiency of selenium was verified by direct (tissue selenium analyses) and indirect (glutathione-peroxidase tissue analyses) methods. In vivo electrocardiographic recordings as well as in vitro electrophysiological and mechanical recordings did not reveal abnormalities in any of the two groups. In conclusion, earlier studies have shown that the combined deficiency of selenium and vitamin E leads to abnormal cardiac function. Selenium deficiency alone, however, does not appear to significantly affect cardiac function in the rat.

Animals↗
PubMed1988

Serum selenium concentration associated with risk of cancer.

The association between serum selenium concentration and risk of cancer was studied in a nested case control study. Case control pairs came from a population of 9364 people examined in 1979. During the six year follow up, 60 men and women aged between 20-54 at the time of blood sampling, who had been free of malignant disease, developed cancer. The mean serum selenium concentration of 1.56 mumol/l (123.2 micrograms/l) in patients was not significantly different from that in controls (1.63 mumol/l (128.7 micrograms/l]. The difference in mean selenium concentration was largest and most significant for haematological malignancies alone. The difference in selenium concentrations in cases of fatal cancer compared with controls was significant (p less than 0.01). The risk of developing adenocarcinomas does not seem to be influenced by serum selenium concentration.

Adenocarcinoma↗
PubMed1988

The selenium-deficient rat heart with special reference to tolerance against enzymatically generated oxygen radicals.

The tolerance against two different levels of enzymatically generated oxygen radicals was studied in isolated Langendorff-perfused hearts from selenium (Se)-deficient and control rats. The glutathione peroxidase activity of the Se-deficient hearts was less than 5% of that of the controls. Examination of the ultrastructure was made after random sampling using morphometric methods. Selenium-deficient hearts demonstrated some areas with myocytes with intracellular oedema. Oxygen radicals (hydrogen peroxide and superoxide) were generated by adding xanthine oxidase for 12 min (high dose: 25 U/l; low dose: 12.5 U/l) and hypoxanthine to the buffer of isolated Langendorff-perfused rat hearts. Left ventricle-developed pressure (LVDP) and high-energy phosphates (ATP and CP) were measured. After the low dose of oxygen radicals, LVDP was reduced to 32.7 +/- 6.5% (mean +/- SEM) of initial values in the Se-deficient group, but only to 58.3 +/- 8.4% in the control group (p less than 0.05). After the high dose, LVDP decreased abruptly to zero in both groups. However, ATP content was significantly (p less than 0.05) lower in Se-deficient than in control hearts. Perfusion with oxygen radicals (low dose) resulted in the appearance of mitochondrial damage in both groups, but intracellular oedema was still present only in the Se-deficient hearts. It is concluded that protection against oxygen radicals was reduced in Se-deficient hearts. This was probably due to loss of myocardial glutathione peroxidase activity.

Adenosine Triphosphate↗
PubMed1987

The Tromsø Heart Study: serum selenium and risk of myocardial infarction a nested case-control study.

The association between serum selenium concentration and the risk of myocardial infarction was studied in a nested case-control study. Altogether 59 men, initially free of disease, aged 28-54 at the time of blood sampling, died suddenly or experienced a fatal or non-fatal myocardial infarction during a six year follow-up period. Case-control pairs came from a population of 9364 persons examined in 1979-80 in the second Tromsø Heart Study. No significant difference was observed between serum selenium in cases and controls (p = 0.34). The major determinants of myocardial infarction and sudden death were raised levels of serum cholesterol and triglycerides (p less than or equal to 0.001) and high systolic blood pressure (p less than 0.05). Thus, in this population with intermediate selenium intake, low serum selenium is not associated with an excess risk of myocardial infarction.

Adult↗
PubMed1987

The Tromsø Heart Study: relationships between the concentration of selenium in serum and risk factors for coronary heart disease.

The association between the concentration of selenium in serum and risk factors for cardiovascular disease was studied in 467 apparently healthy men and women. The concentration of selenium in serum was significantly higher in men than in women (1.63 versus 1.51 mumol/L) (p less than 0.001). A statistically significant positive correlation between serum selenium concentration and total cholesterol was found in women, but not in men. No other statistically significant correlations were observed with the major risk factors for coronary heart disease. There were indications that high consumption of fish, coffee and bread were associated with increased serum selenium levels, but the differences did not reach statistical significance. Our findings suggest that serum selenium concentrations in the range 1.2-2.0 mumol/L are not associated with major risk factors for cardiovascular disease.

Adult↗
PubMed1987

The Tromsø Heart Study: serum selenium in a low-risk population for cardiovascular disease and cancer and matched controls.

High serum selenium concentration may protect against cardiovascular disease and cancer. Seventh-Day Adventists have a low risk for these diseases. This study of 32 Seventh-Day Adventists and matched controls in Tromsø shows that Seventh-Day Adventists have a lower serum selenium concentration (1.45 mumol/litre versus 1.58 mumol/litre, 99% confidence interval of the difference = 0.01-0.24). The difference in serum selenium levels was positively associated with difference in the consumption of fish (p = 0.05), but no association was found with other dietary items. Aspects other than serum selenium concentration must explain the lower incidence of cardiovascular disease and cancer among Seventh-Day Adventists.

Adult↗