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Biomedical subjects

R Rønneberg

Publications and source records attributed to R Rønneberg.

10 recordsLinked to original sources
PubMed1998

Muscle metabolism and quality (MQI) in prediabetic sedentary man.

Twelve pairs of healthy sedentary males matched for their body mass index (BMI) with either a low insulin response (LIR; a stage of prediabetes) or a high (HIR; controls) to a standardized glucose infusion test (GIT) were studied in respect to their exercise capacities (W(OBLA), W(SL) and relative W(OBLA):W(OBLA) x W(SL)(-10 x 100), muscle fiber composition (%ST), muscle citrate synthase activity (CS), muscle ubiquinone (MUQ), MUQ over %ST (muscle quality index, MQI), and peripheral insulin sensitivity (PIS) as described with insulin-clamp techniques (SIGITmean). LIR and HIR displayed normal PIS and positive relationships versus exercise capacity. LIR's but not HIR's relative W(OBLA) was related to CS as earlier only documented in endurance athletes but at a lower level than in athletes. This pointed at a poor peripheral oxygen delivery in LIR. LIR's MQI decreased relative to HIR's the higher the muscle CS indicating radical related muscle trauma in LIR as in athletes. LIR representing prediabetes described muscle anomalies, which could represent prestages of the lesions observed in type-2 diabetes. They are claimed to be responsible for insulin-, glucose-, lipid-resistance, and peripheral circulatory resistance.

Adult↗
PubMed1997

Plasma selenium in healthy man before and after nutratherapy.

Females (n = 28) and males (n = 39) had their plasma analysed for selenium (Se), ubiquinone, alpha-tocopherol (vitamin E), the essential fatty acid (EFA) classes: omega-3 (omega-3, n-3) and omega-6 (omega-6, n-6) fatty acids. Selenium averaged 0.99 +/- 0.03 mumol/l and was positively related to plasma ubiquinone, alpha-tocopherol and the EFA index: the omega-6/omega-3 ratio. Food supplements (nutratherapy) with the lipophilic antioxidants ubiquinone and alpha-tocopherol (Q + E) had no effect on selenium but the addition of omega-3 fatty acids as a fish oil concentrate (Q + E + n-3) had (1.12 +/- 0.05 mumol/l, + 36%, p < 0.001). (Q + E) and (Q + E + n-3) with the addition of selenium (200 micrograms or 2.5 mumol a day) raised selenium but not higher than (Q + E + n-3) itself (1.17 +/- 0.12 mumol/l, p < 0.05). After (Q + E) alone, selenium was related as at base-line to both ubiquinone and alpha-tocopherol but not to any marker for EFA. After (Q + E + n-3), selenium was only related to ubiquinone. An unsatisfactory alpha-tocopherol nutratherapy was suggested as the explanation. EFA or markers for EFA were in no situation related to plasma selenium.

Adult↗
PubMed1994

Magnesium status in healthy free-living elderly Norwegians.

OBJECTIVE: Magnesium (Mg) status has previously not been properly assessed among healthy elderly subjects. METHODS: Thirty-six healthy elderly subjects participated. Their Mg status was assessed by serum Mg, basal urinary Mg output, and with a Mg loading test (30 mmol infused during 8 hours; urine sampled 24 hours), and compared with 53 healthy younger subjects. Their dietary intake was assessed by a quantified food frequency questionnaire. Fourteen of the subjects received 300 mmol Mg to study the effect on Mg status. RESULTS: With the exception of vitamin D in women, average energy and nutrient intakes were adequate. All subjects had serum Mg levels within the reference value of the laboratory. Basal urinary Mg excretion was 3.3 +/- 1.1 mmol/day and 24-hour Mg retention after a Mg load was 28 +/- 16% compared to 6 +/- 11% in younger controls, suggesting Mg deficiency in the elderly. In the 14 subjects who received oral Mg supplementation there was a statistically significant increase in basal urinary Mg excretion and creatinine clearance, and decreases in Mg retention, serum Mg and serum creatinine. CONCLUSIONS: This study suggests that a significant subclinical Mg deficit, not detected by serum Mg, was present in many of these healthy elderly subjects. Mg supplementation improved Mg status and renal function.

Aged↗
PubMed1992

Essential fatty acids in human colostrum.

We analyzed the colostrum of 11 mothers, consuming a normal hospital diet, for total fat content and various fatty acids. Three of the mothers had given birth four weeks prematurely. Total fat content of the colostrum ranged from 2.16 to 3.65 g/100 ml. The major fatty acids were palmitic acid (16:0) and oleic acid (18:1) (24.3 and 39.7% (w/w), respectively). The dominating polyunsaturated fatty acid was linoleic acid (18:2n-6) (11.5% of the total fatty acids). Linolenic acid (18:3n-3) and docosahexaenoic acid (22:6n-3) accounted for 0.7 and 0.6%, respectively, of the sum of total fatty acids. The ratio of polyunsaturated to saturated fatty acids was 0.42, ranging from 0.28 to 0.5, and the ratio of n-6/n-3 fatty acids was 6:1. Linoleic acid and linolenic acid were positively correlated with each other (p < 0.02), whereas palmitic acid was negatively correlated with oleic acid (p < 0.05). We conclude that the average human colostrum contains the recommended level and balance of the essential fatty acids required by the newborn baby.

Colostrum↗
PubMed1991

Comparative absorption of calcium from carbonate tablets, lactogluconate/carbonate effervescent tablet, and chloride solution.

Intestinal absorption of calcium from three different labelled calcium preparations (all containing 500 mg elemental calcium) was determined using the whole body retention and urinary excretion of 47Ca in 14 normal subjects. Chewable calcium carbonate tablets showed a significantly (p less than 0.05) better mean minimum absorption of calcium (25.6% in exp. I, 22.8% in exp. II) than calcium given in the form of a lactogluconate/carbonate effervescent tablet, (17%), but similar to calcium in a chloride solution (24.7%). The minimum calcium absorption varied from 85 to 128 mg. All the preparations were taken with standardized low calcium test meals.

Adult↗
PubMed1989

Effect of fish oil on blood pressure and blood lipids in men with mild to moderate hypertension.

Forty men with mild to moderate hypertension were given one of two dietary supplements for 6 weeks: 20 capsules of fish oil (MaxEPA) or placebo (olive and corn oil). The MaxEPA supplement provided about 7 g omega-3-fatty acids pr day, whereas the placebo contained about 7 g omega-6-fatty acids and only 0.2 g omega-3-fatty acids. A clinical insignificant reduction in blood pressure was noted in both groups. In the fish oil group, the serum triglyceride levels fell by 30%. A decrease in the ratio total cholesterol/high density lipoprotein (HDL-) cholesterol was noted in both groups, most pronounced in the placebo group. No significant effect on total serum cholesterol level was observed during this study.

Adult↗
PubMed1987

Comparative metabolism of erucic and oleic acid in hepatocytes from rats fed partially hydrogenated marine oil or palm oil.

Rats were fed for 8 weeks high fat diets containing 20% of either palm oil (PO) or linoleic-supplemented partially hydrogenated marine oil (PHMO). Hepatocytes were isolated from rats fasted overnight. Incubations were performed with albumin bound [10-14C] oleic acid and [14-14C] erucic acid, respectively, for 15 or 60 min. The cell viability was better than 90% after 60 min of incubation. The incorporation of radioactive metabolites into lipids of the cells and of the secreted products was determined. The uptake and channelling of 18:1 and 22:1 into various lipid classes in the hepatocytes were different, but were little influenced by the diets. Erucic acid disappeared more rapidly from the incubation medium than 18:1 at both incubation times and for both dietary groups, and was mainly incorporated into the hepatocyte triglycerides and found in the free fatty acid pool, whereas only small amounts of labelling were detected in the phospholipids. Oleic acid, however, was readily incorporated into both phospholipids and triglycerides, and little was found in the free fatty acid pool. For both the triglycerides and the free fatty acids more than 90% of the radioactivity was represented by the incubation fatty acid. Chain-shortened products were found in the phospholipids, especially after incubation with 22:1. The chain-shortening capacity was somewhat higher in the PHMO group, relative to the PO group. At both incubation times, the major part (80-90%) of the total radioactivity was found in the lipid-soluble fraction of the incubation medium, and for both groups 60-80% still as the original incubation fatty acid. 20-30% of the radioactivity was found in the triglycerides secreted from the cells. Phospholipids were secreted in minor amounts (1-5%). Water soluble products constituted 3-7% at 15 min of incubation, increasing to 10-12% at 60 min, highest when incubating with 22:1 and similar for both dietary groups.

Animals↗
PubMed1986

Influence of dietary fat on metabolism of (14-14C)erucic acid in the perfused rat liver. Distribution of metabolites in lipid classes.

Two groups of rats were fed diets containing 20% by weight of either partially hydrogenated marine oil supplemented with sunflower seed oil (PHMO) or palm oil (PO) for 8 wk. Using a liver perfusion system, the effect of dietary long chain monoenoic fatty acids on the uptake and metabolism of [14-14C]erucic acid was studied. The perfusion times were 15 and 60 min, respectively. The two groups showed equal ability for erucic acid uptake in the liver but differed in the channeling of the fatty acids into various metabolic pathways. A higher metabolic turnover of 22:1 in the PHMO livers relative to the PO livers was demonstrated by an increased recovery of total [14C]labeling in the triglyceride (TG) and phospholipid (PL) fractions, already evident after 15 min of perfusion. The chain-shortening capacity was highest in the PHMO group, reflected by a higher [14C]18:1 incorporation in both TG and PL, and increasing from 15 to 60 min of perfusion. The amount of [14C]18:1 found in PL and TG after 60 min of perfusion of livers from rats fed PO corresponded to that shown for the PHMO group after 15 min. The PL demonstrated a discrimination against 22:1 compared to TG, and, when available, 18:1 was highly preferred for PL-synthesis. The total fatty acid distribution in the TG, as determined by gas liquid chromatography (GLC), reflected the composition of the dietary fats. In the total liver PL, 22:1 and 20:1 were present in negligible amounts, although the PHMO diet contained 12-13% of both 22:1 and 20:1. In the free fatty acid fraction (FFA), the major part of the radioactivity (approximately 80%) was [14-14C]erucic acid, and only small amounts of [14C]18:1 (less than 2%) were present, even after 60 min of perfusion. The shortened-chain 18:1 was readily removed from the FFA pool and preferentially used for lipid esterification.

Animals↗
PubMed1986

Effects of feeding high-fat diets to rats: metabolism of erucic acid (C 22:1 n-9) in the perfused liver and secretion of metabolites to the perfusate.

The liver metabolism of erucic acid, 22:1 n-9, was studied in rat livers perfused with 14-14C-labelled erucic acid for 15 and 60 min, determining the distribution of radioactivity in the perfusate and in the lipids of the liver cell organelles. The rats were adapted to a high-fat diet containing either partially hydrogenated marine oil (PHMO) or palm oil (PO), both adjusted to a 10% content of linoleic acid. The results showed an efficient uptake and metabolism of erucic acid with the secretion to the perfusate medium of labelled free fatty acids other than erucic acid, labelled phospholipids as well as water soluble oxidation products. Only minor amounts of secreted labelled triglycerides were found within 60 min of perfusion. In the liver, labelled lipids accumulated in the endoplasmic reticulum, after 15 min mainly as free fatty acids, after 60 min as triglycerides. The esterification pathway, including the erucic acid given as well as chain-shortened fatty acids, seemed to be preferred under the experimental conditions and with adequate linoleic acid in the diet. A chain shortening of erucic acid probably took place in both peroxisomes and mitochondria shown by the presence of labelled 18:1 and 20:1 in the organelle-bound phospholipids. A chain shortening was found in both dietary groups, and is assumed to be an affect of the adaptation to a high-fat diet rather than an effect of dietary very long chain monoenoic fatty acids. Somewhat higher levels were found in the PHMO group, but the difference in the dietary fat was not a major factor in the liver lipid adaptation.

Animals↗