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Biomedical subjects

A Astrup

Publications and source records attributed to A Astrup.

At least 199 records · Page 11Linked to original sources
PubMed1989

[Bioimpedance analysis in determining body composition. Testing of a new simple apparatus].

In the assessment of human body composition, only expensive and time consuming methods have hitherto been available. Recently, the new bioimpedance method has been introduced. It offers an easy, quick, inexpensive and noninvasive measurement with an accuracy comparable to that of the classical methods. A new inexpensive Danish apparatus was tested against the most used and validated equipment. Fifteen normal subjects underwent measurements with both apparatuses. The two methods gave identical results with a coefficient of correlation of 0.99 and a coefficient of variation of 5.6%. The apparatus can be recommended for clinical and scientific purposes.

Adolescent↗
PubMed1989

Changes of high-energy phosphorous compounds in skeletal muscle during glucose-induced thermogenesis in man. A 31P MR spectroscopy study.

By the use of invasive techniques, skeletal muscle has been shown to contribute to thermogenesis induced by glucose in humans. In an attempt to study this phenomenon by a non-invasive method, this study investigated intracellular high-energy phosphorous compounds in calf muscle by 31P MR spectroscopy during an oral glucose load in healthy lean subjects. The inorganic phosphate concentration increased gradually (P less than 0.05) after glucose intake. The phosphocreatine/inorganic phosphate rate decreased (P less than 0.05) and the estimated ADP concentration increased. ATP and intracellular pH remained unchanged after the glucose administration. No changes were seen in the control experiments. The processes responsible for the decreased energy state of the skeletal muscle cell may be an obligatory conversion of glucose to glycogen. Also, facultative processes, such as sodium/potassium pumping and substrate cycles stimulated by the sympatho-adrenal system, may be partly responsible.

Adenosine Diphosphate↗
PubMed1989

Epinephrine mediates facultative carbohydrate-induced thermogenesis in human skeletal muscle.

The thermic effect of carbohydrate has a component mediated by the sympathoadrenal system but of unknown anatomical localization. We have studied the contribution of skeletal muscle to the thermic effect of a carbohydrate-rich natural meal (115 g of carbohydrate, approximately 80% of energy) by means of the forearm technique on two occasions, with and without intravenous beta-blockade with propranolol. The meal-induced thermogenesis was reduced from 9.6 to 7.1% by beta-blockade (P less than 0.04), the major difference was found 90 to 240 min after the meal. The postprandial increments in plasma glucose and lactate did not change by beta-blockade, but there was a trend toward a decreased insulin response (P = 0.06). The carbohydrate-induced increase in forearm oxygen consumption was reduced by 23% after beta-blockade (P less than 0.05), the entire difference being present 90-180 min postprandially and coinciding with the peak in arterial epinephrine. The present study provides evidence of a facultative thermogenic component in skeletal muscle, mediated by epinephrine via beta 2-adrenoreceptors. However, it also points to a nonmuscle component mediated through beta 1-adrenoceptors by norepinephrine released from the sympathetic nervous system. Consequently, the sympathoadrenal system seems to play a physiological role in the daily energy balance.

Adult↗
PubMed1989

A randomized comparison of horizontal and vertical banded gastroplasty: what determines weight loss?

Pouch volume, stoma diameter, and pouch emptying rate were measured postoperatively and after 6 months in 45 morbidly obese patients who had been assigned to either horizontal gastroplasty (HGP) or vertical banded gastroplasty (VBGP) after pretreatment with diet alone. Pouch volume and stoma diameter were measured by a standardized radiographic method with blinded assessment by two observers. Pouch emptying rate was determined by a standardized scintigraphic method and expressed as the mean transit time (t60). Pouch volume and stoma diameter did not change, whereas t60 decreased by 36% during the first 6 months after HGP (p less than 0.001). Pouch volume was larger after HGP (p less than 0.001). Pouch emptying was faster after VBGP (p less than 0.001), but these patients had the better weight loss (p less than 0.001). Variation in weight loss after either operation was unrelated to pouch volume, stoma diameter, and t60. Stoma diameter was not correlated with t60. The study provides further evidence against the significance of stoma diameter and pouch emptying rate as determinants of weight loss after gastroplasty. The much smaller pouch volume after VBGP may favor weight loss.

Adult↗
PubMed1989

VLCD compliance and lean body mass.

Very low calorie diets (VLCD) have many advantages, as they are inexpensive, safe and easy to comply with, and give rapid and encouraging weight loss. On the other hand, many patients complain of hunger and constipation. We have shown that these drawbacks can be reduced by the supplementation of 30 g of dietary fibre to VLCD. By the use of a VLCD which provides approximately 60 g of protein for women and approximately 70 g for men, the dietary regimen is safe and no excessive loss of lean body mass seems to occur during VLCD in obese patients. However, the changes in body composition that may occur after cycles of weight loss and regain have not been clarified. After weight cycles with weight losses obtained by conventional diets, obese women have lower lean body mass than obese non-dieting controls. Hence, more information about the changes in body composition during dieting on conventional diets and VLCD are needed.

Body Composition↗
PubMed1989

Initial very low calorie diet (VLCD) improves ultimate weight loss.

Thirty-eight consecutive obese persons were treated as outpatients. The treatment commenced with VLCD formula diet NUPO (females 388 kcal, 1600 kJ, 56 g protein; males 446 kcal, 1864 kJ, 69 g protein). VLCD had no untoward effects and was continued for as long as the patient would accept. After that the formula diet was supplemented with ordinary items of food and drink to the level of 1000 kcal (4200 kJ) for women and 1100 kcal (4600 kJ) for men. After 5 months the data were analyzed separately according to the duration of VLCD: group 1 (n = 20): VLCD for less than 2 months, and group 2 (n = 18): VLCD for 2 months or more. The two groups were comparable with regard to height, absolute weight and percentual overweight, but group 2 was somewhat older than group 1 (49.5 vs 38.3 years, P less than 0.01). Group 2 lost significantly more weight, both totally (17.1 kg (7.8-40.1] and on VLCD alone (12.3 kg (4.1-28.8], than group 1 (8.7 kg (-1.1 to 19.1), P = 0.008; and 7.3 kg (0.9-18.2 P = 0.01). Weight losses in both groups eliminated or strongly reduced the need for a wide variety of expensive drugs: antidiabetics, diuretics, antihypertensives, analgetics, etc. It is concluded that VLCD is an effective and encouraging way of starting a dieting program, and that it should be continued for at least two months, as the length of the initial VLCD period related significantly to the amount of weight eventually lost.

Adolescent↗
PubMed1988

Secondary hyperparathyroidism of morbid obesity regresses during weight reduction.

In order to test the relation between obesity and the secondary hyperparathyroidism found in markedly overweight subjects, 24 morbidly obese patients were studied before and after a weight loss of 35.9 kg obtained by a nutritionally adequate, intermittent very-low-calorie diet. Overweight was reduced from 98 +/- 34% to 44 +/- 19%. Serum total calcium did not change, but serum ionized calcium (Ca2+) increased from 1.22 +/- 0.04 mmol/L to 1.25 +/- 0.04 mmol/L (P less than .001). A corresponding fall was observed in serum parathyroid hormone (s-PTH), which decreased from 47.2 +/- 21.7 pmol/L to 35.2 +/- 19.4 pmol/L (P = .01). The change of s-PTH was positively associated with the reduction of body weight (r = .50, P less than .05) and with the reduction of overweight (r = .55, P less than .01). Regarding calcium binding substances, serum albumin remained low. The initially lowered serum phosphate and bicarbonate both rose (P less than .001). Plasma lactate and plasma free fatty acids (FFAs) decreased (P less than .001). The study supports our hypothesis that the change profile of calcium complexing anions in obesity interferes with the tubular reabsorption of calcium, which in turn lowers serum Ca2+, thus promoting hyperparathyroidism. Along with weight loss, concentrations of calcium complexing anions returns towards normal values and the secondary hyperparathyroidism regresses.

Adult↗
PubMed1988

Angiotensin II attenuates reflex decrease in heart rate and sympathetic activity in man.

Circulatory variables and hormone concentrations in arterial plasma were measured in six normal subjects during angiotensin II (ANG II) step-up infusion of 0.25 and 1.00 ng kg-1 X min. During the 1.00 ng kg-1 X min infusion ANG II plasma concentrations increased from 11 +/- 2 to 48 +/- 6 pg ml-1; i.e., similar to those obtained during acute hypotensive hypovolaemia in man. Mean arterial pressure increased (P less than 0.05) from a resting value of 89 +/- 3 to 97 +/- 5 mmHg. Heart rate and catecholamine concentrations did not change. Plasma aldosterone increased (P less than 0.05) from 36 +/- 4 to 77 +/- 10 pg ml-1 during the infusion. Plasma concentrations of vasopressin, adrenalin and pancreatic polypeptide did not change during the investigation. During the 0.25 and 1.00 ng kg-1 X min infusion subcutaneous blood flow decreased (P = 0.06) to 67 +/- 20 and 66 +/- 26%, respectively, of control. It is concluded that: (1) ANG II in physiological doses in man may augment the sympathetic activity on the circulatory system since compensatory decreases in heart rate or in plasma catecholamines were not observed during the increased arterial pressure; (2) ANG II does not induce a general decrease in vagal tone as plasma pancreatic polypeptide concentrations were unchanged; (3) the obtained plasma concentrations of ANG II do not stimulate the release of vasopressin to plasma; and (4) the threshold for reducing the subcutaneous blood flow is reached within relatively small increments in plasma ANG II.

Angiotensin II↗
PubMed1988

Measurement of forearm oxygen consumption: role of heating the contralateral hand.

The classical forearm technique widely used for studies of skeletal muscle metabolism requires arterial cannulation. To avoid arterial puncture it is becoming more common to arterialize blood from a contralateral hand vein by local heating. This modification and the classical method have produced contradictory results regarding the contribution of skeletal muscle to glucose-induced thermogenesis. The effect on forearm circulation and the metabolism of heating the contralateral hand was examined before and after an oral glucose load. The results suggest that contralateral heating increases subcutaneous blood flow and decreases skeletal muscle blood flow. This facilitates mixing of superficial blood with deep venous blood. Contralateral heating increased deep venous oxygen saturation and abolished the pronounced glucose-induced increase in oxygen consumption observed in the control experiments after glucose. Heating increased rectal temperature by 0.6 degrees C, and plasma norepinephrine levels were increased compared with the control experiments. The present study explains the conflicting reports on glucose-induced thermogenesis in skeletal muscle and warns against heating the contralateral hand when using the forearm technique.

Adult↗
PubMed1987

Tissue/blood partition coefficients for xenon in various adipose tissue depots in man.

Tissue/blood partition coefficients (lambda) for xenon were calculated for subcutaneous adipose tissue from the abdominal wall and the thigh, and for the perirenal adipose tissue after chemical analysis of the tissues for lipid, water and protein content. The lambda in the perirenal tissue was found to correlate linearly to the relative body weight (RBW) in per cent with the regression equation lambda = 0.045 . RBW + 0.99. The subcutaneous lambda on the abdomen correlated linearly to the local skinfold thickness (SFT) with the equation lambda = 0.22 SFT + 2.99. Similarly lambda on the thigh correlated to SFT with the equation lambda = 0.20 . SFT + 4.63. It is concluded that the previously accepted lambda value of 10 is generally too high in perirenal as well as in subcutaneous tissue. Thus, by application of the present regression equations, it is possible to obtain more exact estimates of the adipose tissue blood flow measured with the 133Xe wash-out method.

Adipose Tissue↗
PubMed1987

Increased plasma fibronectin concentrations in obesity: normalization during weight loss.

In 23 morbidly obese patients we investigated the influence of a large weight loss (30.6 kg, range 17.5-90.8) on the plasma fibronectin concentrations. Further, changes in plasma fibronectin were related to serum insulin levels and to liver biochemistry. Between the measurements patients had been treated with an intermittent very-low-calorie formula diet sufficient in respect to protein, minerals and vitamins. They were investigated in weight-stable states. Before weight reduction, 14 patients (61%, 95% confidence limits 39-80%) had elevated plasma fibronectin levels. Plasma fibronectin decreased (medians 1.22 and 0.59 mumol/l before and after weight loss, p less than 0.01) and was after weight loss within the normal range in 14 patients. The change in plasma fibronectin was unassociated with the magnitude of the weight loss as well as with the reduction of overweight. The resulting plasma fibronectin levels were also uncorrelated with the body weight and with the final degree of overweight. Serum insulin decreased (p less than 0.01) during the weight reduction and the change correlated (p less than 0.05) with the change in plasma fibronectin. Serum lactate dehydrogenase, which is associated with the degree of hepatic fatty change, declined (p less than 0.01), but the individual change was unrelated with the change in plasma fibronectin. In conclusion, the elevated plasma fibronectin levels in morbidly obese subjects seem to normalize during weight loss. We suggest the normalization to be mediated--at least in part--by a reduction of the insulin levels.

Adult↗
PubMed1987

Blood flow in skin, subcutaneous adipose tissue and skeletal muscle in the forearm of normal man during an oral glucose load.

Blood flow to the forearm, and the subcutaneous tissue and skin in the forearm were measured by strain gauge plethysmography, 133Xe-elimination and Laser Doppler flowmetry during an oral glucose load (I g glucose kg-1 lean body mass) and during control conditions. The forearm blood flow remained constant during both experiments. Glucose induced a two-fold vasodilatation in subcutaneous tissue. In skin, glucose induced a relative vasodilatation and later a relative vasoconstriction compared with control experiments. When estimated from forearm blood flow and subcutaneous and skin blood flows, muscle blood flow decreased about 20-30% during both experiments. Proximal nervous blockade did not abolish the glucose-induced vasodilatation in subcutaneous tissue. In the glucose experiment, arterial glucose concentration increased to 7.8 +/- 1.17 mmol l-1 30 min after the load was given and then decreased to 4.5 +/- 0.34 mmol l-1 at the end of the experiment. In the control experiments glucose concentration was constant. Arterial noradrenaline concentration increased significantly from 1.0 +/- 0.13 to about 1.5 +/- 0.3 nmol l-1 120 min after glucose and remained at this level during the experiment. Similarly adrenaline increased from 0.16 +/- 0.11 to about 0.4 +/- 0.16 nmol l-1 180 min after glucose. It is hypothesized that the vasodilating effect of glucose in subcutaneous tissue is secondary to metabolic events connected to glucose uptake and energy deposition in adipose tissue.

Adipose Tissue↗
PubMed1987

Horizontal or vertical banded gastroplasty after pretreatment with very-low-calorie formula diet: a randomized trial.

Horizontal and vertical banded gastroplasty (GP) were compared as to their effectiveness and side-effects in patients pre-treated for morbid obesity with a very-low-calorie formula diet (VLCD). The pre-treatment served to select the compliant patients, to minimize the surgical hazard, and to optimize the total weight reduction. Seventy-four consecutive patients (median age 34 years, median body weight 125.1 kg, and median overweight 93 per cent) were included according to the criteria for entry. The median weight loss on VLCD was 25.7 kg (range, 5.8-92.6 kg) and the median overweight reduction reached 46 per cent of the initial overweight (range, 9-83 per cent). Only few and mild side-effects were observed. Sixty-nine per cent of the patients fulfilled our criterion for surgery by reducing their initial overweight by at least 40 per cent. Of these, 23 and 22 patients were assigned respectively to either vertical banded or to horizontal GP. Patients and dietitians were not informed of the assignment. A significant weight loss occurred in both groups. Three months after surgery weight loss after vertical banded GP proved to be the larger (P less than 0.001). The difference became even more pronounced due to an earlier regain among patients treated with the horizontal GP. Thus, at 12 months, the net weight loss after surgery was 9.7 kg (range, -28.2-28.7 kg) in the vertical banded GP group and -1.0 kg (range, -15.0-36.5 kg) in patients treated with horizontal GP (P less than 0.0005). At this time, the total weight loss in the groups was 48.5 kg (range, 6.4-104.0 kg) and 32.6 (range, 3.7-125.1 kg) respectively (P less than 0.02), and the total reduction of overweight was greater in the group treated with vertical banded GP (80 per cent (range, 10-96) versus 56 per cent (range, 8-92), P less than 0.005). There were no deaths, and side-effects to VLCD as well as to GP were generally mild. It is concluded that vertical banded GP is more effective than horizontal GP and that the former operation adds a significant weight loss to that obtained by VLCD. The combined treatments offer a weight reduction comparable to that observed after jejunoileal bypass. However, some regain within 1 year makes it questionable if the vertical banded GP is sufficient to prevent weight regain.

Adult↗