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Biomedical subjects

L Hambraeus

Publications and source records attributed to L Hambraeus.

At least 37 records · Page 2Linked to original sources
PubMed1996

Mild overcooling increases energy expenditure during endurance exercise.

Intensive cooling has been shown to increase energy expenditure (EE) during work as well as to decrease physical performance. Two different levels of moderate cooling (10 degrees C vs 15 degrees C) were studied during light endurance exercise in order to examine the effect of the increased heat loss on EE. Twelve subjects performed a 90-min low intensity exercise (100 W) on a cycle ergometer, wearing a water-cooled calorimeter suit for controlled cooling. The lower temperature resulted in a 4.3 +/- 3.8% (mean +/- SD) higher EE, increased total heat loss and lowered skin temperatures. No differences in central core body temperature, heart rate or respiratory quotient (RQ) were recorded. There was a relation between differences in the rate of heat loss and the corresponding increase in EE. Even a small increase in cooling during endurance exercise increased EE which may be a relevant problem in winter sports.

Adult↗
PubMed1995

Shift related dietary intake in day and shift workers.

To study the impact of work hours on eating habits the dietary intake of 96 male industrial workers on day work and two- and three-shift work was investigated using repeated 24 h recall. The intake of energy, 14 nutrients, and coffee and tea was computed, using a nutrient data base, for 8 h work and shifts (day, morning, afternoon, night) and for the 24-h periods including these work shifts. No changes in intake of energy, nutrients and coffee/tea were observed between 8 h morning and afternoon shifts, but there was a reduction in intake during 8 h night shifts. Night shift work caused a redistribution of food and coffee intake, but not an overall 24 h reduction. On the whole, the energy-intake and the quality of food intake (percentages of energy from macronutrients and density of micronutrients) were not affected by shift work, although the intake of carbohydrates was lower in day- and three-shift workers during days off. The intake of alcohol was higher during days off in all groups. In summary, two- and three-shift work in this study affected the circadian distribution of food intakes and coffee consumption, but not the overall 24-h consumption.

Adult↗
PubMed1994

Growth hormone-dependent insulin-like growth factor binding protein is a major determinant of bone mineral density in healthy men.

To establish the major determinants of bone mass, we assessed relationships between bone mineral density (BMD) and height, weight, body mass index (BMI), muscle strength, physical capacity (VO2max), body composition, serum concentrations of insulin-like growth factor I (IGF-I), growth hormone (GH), the GH-dependent IGF binding protein (IGFBP-3), testosterone, sex hormone binding globulin (SHBG), osteocalcin, and parathyroid hormone (PTH) in 38 healthy men between 25 and 59 years of age. Values of BMD at all sites (total body, lumbar spine, and hip) were strongly correlated with IGFBP-3 (r = 0.51-0.64, p < 0.001 at all sites), and total-body BMD was also significantly correlated with IGF-I (r = 0.43, p = 0.01). BMD measurements of the total body and of the different sites of the hip were negatively correlated with age and positively with weight, BMI, muscle strength, VO2max, and fat-free weight. IGF-I and IGFBP-3 were both positively related to muscle strength and VO2max. In a stepwise forward multiple-regression analysis, the best model was obtained for the femoral neck, where IGFBP-3, GH, PTH, age, IGF-I, and BMI explained 77% of the variation in BMD. The partial regression coefficients of IGFBP-3, PTH, and BMI were all positive, whereas age, GH, and IGF-I were negatively correlated with BMD. In summary, IGFBP-3 correlated better with BMD than any other study parameter. The findings indicate that GH is of importance for bone mass and suggest that IGFBP-3 not only reflects the integrated GH secretion but also has a direct role in the endocrine regulation of bone metabolism.

Absorptiometry, Photon↗
PubMed1994

A suit calorimeter for energy balance studies on humans during heavy exercise.

A modification of the suit calorimeter originally developed in 1972 was used in combination with indirect respiratory calorimetry. The modification included increased cooling capacity of the suit by means of an increased density of cooling tubes and a variable water flow pump which permitted higher flow rates. This has made the suit calorimeter a very effective heat exchanger that could be used for studies on high energy turnover during heavy exercise. Furthermore, specially designed absorption clothing made it possible to collect any sweat produced before it evaporated, thus minimizing potential error in measuring evaporative heat loss. The suit calorimeter would seem to offer a valuable tool in the analysis of the specific thermogenic responses to dietary changes and physical activity in studies on energy and protein metabolism and their interaction in humans. It also makes it possible to perform direct calorimetric measurements in metabolic balance studies using continuous parenteral infusion since the subjects do not need to be sealed in a calorimeter chamber.

Adolescent↗
PubMed1994

Nocturnal eating and serum cholesterol of three-shift workers.

OBJECTIVES: The goal of this study was to examine the effect of rotating three-shift work on the circadian distribution of dietary intake and to investigate the relationships between displaced eating and nutritional status variables [blood lipids, blood glucose, body mass index (BMI)]. METHODS: Dietary data were collected by 147 replicate 24-h dietary recalls from 22 male industrial workers in rotating three-shift work. The intakes of energy and nutrients were estimated by the use of a nutrient data base. The BMI was calculated, and blood glucose, serum triglycerides, high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) cholesterol were measured once. RESULTS: The dietary intakes of energy, protein, total fat, saturated fat, total carbohydrates, sucrose, and dietary fiber did not differ between 24-h periods but did differ between work shifts and were lowest during the night. Correlation analyses between dietary intakes and nutritional status parameters showed that those who redistributed their eating most to the night shift had higher levels of serum total cholesterol and LDL and a higher LDL:HDL ratio; 63% of the LDL cholesterol level was explained by carbohydrate intake during night shifts. In contrast, the total intake for whole 24-h periods or across entire shift cycles was not related to serum variables or BMI. CONCLUSIONS: Dietary intake is lower during night shifts (34-37% of 24-h intake of various nutrients) than during morning shifts (43-47%) and afternoon shifts (47-59%). The redistribution of food intake to the night may be associated with metabolic disturbances in lipid metabolism.

Adult↗
PubMed1993

Determination of body composition--a comparison of dual-energy x-ray absorptiometry and hydrodensitometry.

Determination of body composition by dual-energy x-ray absorptiometry (DEXA) was evaluated in healthy men, by using underwater weighing (UWW), skinfold thickness measurement, and bioimpedance analysis. There were strong correlations between percent body fat obtained by all techniques, but DEXA gave significantly lower values (P < 0.001). The influence of differences in bone mineral density (BMD) on fat content determined by UWW was also studied. The individual differences between UWW and DEXA fat estimates were calculated and there was a negative correlation with BMD (r = -0.50, P < 0.05). There was also a negative correlation between body fat by UWW and BMD (r = -0.71, P < 0.01) in the subjects with lowest fat by DEXA, indicating that high or low BMD gave false values by UWW. In conclusion, DEXA and UWW provide complementary information and a combination of these techniques seems to offer new opportunities in evaluations of body composition.

Absorptiometry, Photon↗
PubMed1992

Iron absorption differs in piglets fed extrinsically and intrinsically 59Fe-labeled sow's milk.

Iron bioavailability from species-specific milk is assumed to be high for the offspring, possibly due to species-specific iron-binding proteins in the milk. To assess this bioavailability using radioisotopes, the validity of extrinsic labeling technique needs to be proven. Using the suckling piglet as an animal model, we have compared iron bioavailability from sow's milk labeled extrinsically and intrinsically. During intrinsic labeling transfer into milk of 59Fe given intramuscularly was slow and was found to be at maximum 14 h post-injection. Recovery of isotope in the milk was only 0.00014%. Extrinsic and intrinsic labels were distributed differently among milk fractions; intrinsic iron bound primarily to the fat fraction but the extrinsic iron bound primarily to the casein fraction. Iron retention from intrinsically labeled milk was considerably higher than from extrinsically labeled milk. These results show that the extrinsic tag method is not valid for studies on iron absorption from sow's milk and suggest that the situation may be the same for human milk.

Absorption↗
PubMed1991

[Influenza and death. High mortality not only due to the great epidemics].

Excess mortality in a population is one of the hallmarks of an influenza epidemic. Apart from the pandemic years, 1918-1919, 1957 and 1968-1969, annual excess mortality has occurred 16 times in Sweden during the period 1911-1988. An unusually high mortality was caused by Influenza A Sichuan 2/87 (H3N2), the unexpected appearance of which at the beginning of November 1988 started an intensive epidemic in Sweden, while other European countries had a relatively mild influenza season. Swedish deaths in December totalled 10,500-2,200 more than expected; age groups over 65 years accounted for 95 per cent of the mortality, and those over 80 (N = 350,000 in Sweden) for 1,400 deaths. 0.4 percent of those over 80 died. The excess mortality is to be explained by the high proportion of the elderly in the Swedish population and the very low rate of influenza vaccination before the outbreak. As the increase in the proportion of the very elderly can be expected to continue, future influenza epidemics will result in even higher mortality unless adequate prophylactic measures are taken.

Adult↗
PubMed1989

Evaluation of urinary 3-methylhistidine excretion in infection by measurements of 1-methylhistidine and the creatinine ratios.

When 3-methylhistidine (3MH) excretion is used as an indicator of myofibrillar protein catabolism, there are restricting factors, such as meat intake, incorrect 24-h urine collections, and a large interindividual variation in basal excretion. 1-Methylhistidine (1MH) was previously suggested as an indicator of meat intake. We studied the basal urinary excretion of 1MH and whether this was influenced by infection and we compared the use of 3MH vs the 3MH:creatinine ratio (3MH:Cr) in detecting changes during infection. The basal excretion of 1MH was 84.9 mumol/24 h and its creatinine molar ratio (1MH:Cr) was 7.4 x 10(-3) with no change during infection. Because 1MH:Cr was significantly increased in 4 of 14 patients, their 3MH values were considered influenced by meat intake and thus discarded. Among the remaining 10 patients, 9 showed a significant individual increase in 3MH:Cr during infection compared with only 4 in 3MH. This was due to a higher precision in 3MH:Cr despite the concomitant significant increase in urinary creatinine excretion.

Adolescent↗
PubMed1987

Urinary excretion of 1-methylhistidine: a qualitative indicator of exogenous 3-methylhistidine and intake of meats from various sources.

In order to investigate whether the urinary excretion of 1-methylhistidine (1MH) might serve as an objective indicator of meat ingestion and exogenous 3-methylhistidine (3MH) intake, healthy subjects were fed an ovolactovegetarian diet. At five-day intervals they were given meat of different origin and 24-hour urinary excretions of 1MH and 3MH were determined. After beef intake there was a marked increase of 3MH and 1MH excretion. The elimination curves were found to follow first-order kinetics and to indicate similar elimination rates. 1MH was present in ten different types of meat analyzed. A strong linear relationship was found between increase in 3MH and 1MH excretion and the amount of chicken, pork, or plaice ingested. IMH may serve as an objective indicator of meat and exogenous 3MH intake, since it is present in meat, and, regardless of source, shows similar dose-independent kinetics, and has similar half-life to 3MH.

Adult↗
PubMed1985

Relationship between weight reduction and state of malabsorption after jejunoileal bypass for excessive obesity.

A 10-year follow-up study of 30 patients subjected to jejunoileal bypass surgery for obesity is reported. The technique used which resulted in a jejunoileal shunt length of 50-55 cm gave satisfactory weight reduction in 75 per cent of the patients. There were no serious complications. The weight loss occurred essentially during the first 12-18 months, the main cause being defective digestion and malabsorption. In some instances this was supported by initially reduced food consumption. A certain degree of steatorrhoea persists in most cases after 10 years and may be of importance in the maintenance of the new stable weight level.

Adult↗
PubMed1984

Intake of thiocyanate by way of milk and its possible effect on thyroid function.

The keeping quality of milk can be improved if the lactoperoxidase system is activated. To make such an activation efficient the thiocyanate concentration has to be increased. Since, however, thiocyanate has a potent antithyroid effect, thyroid function has been studied in 37 healthy individuals during 12 wk of daily intake of 8 mg thiocyanate by way of milk. The thiocyanate increased significantly in serum and reached a maximum value after 4 wk (+3.8 mg/1). The increased serum levels coincided with an increased excretion in urine (+ 4.8 mg/g creatinine). The levels of thyroxine, triiodothyronine, and thyrotropic hormone were all in the normal range at the beginning of the investigation and no significant changes were found during the experimental period. In conclusion, a daily intake of 8 mg thiocyanate by way of milk does not have any apparent effect on the thyroid function.

Adolescent↗
PubMed1984

The human milk contents of iron, copper, zinc, calcium and magnesium in a population with a habitually high intake of iron.

The contents of iron, copper, zinc, calcium and magnesium were determined in human milk samples from 18 Ethiopian and 23 Swedish women. The Ethiopian women belonged to two groups with different socio-economic situations, a non-privileged and a privileged group. Both groups had an excessively high dietary iron intake--20 to 30 times that of the Swedish women--from the iron-rich traditional diet. In spite of this, the mean concentrations of iron in the milk, as well as of zinc and magnesium, were similar in all three groups. The mean copper concentration, however, was significantly lower in the Ethiopian than in the Swedish milk samples, the lowest mean value occurring in the privileged group. In contrast, a significantly higher mean calcium concentration was found in milk samples from the Ethiopian women than from the Swedish, the highest mean concentration being noted in the non-privileged group. The levels of minerals in breast milk showed no correlation to the birth weight of the infants or the length of gestation. Our data suggest that an excessively high dietary iron intake does not increase the breast milk content of iron in mothers with a good iron status. The reasons for the differences in the content of copper between the Ethiopian and Swedish milk samples are unclear. The higher calcium content in milk from the Ethiopian mothers, despite a low dietary calcium intake may be a result of an increased endogenous cholecalciferol synthesis due to greater exposure to sunshine.

Calcium↗