PubMed Health⌕ Search

Biomedical subjects

J Bülow

Publications and source records attributed to J Bülow.

At least 91 records · Page 5Linked to original sources
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

Vasomotion in human skin before and after local heating recorded with laser Doppler flowmetry. A method for induction of vasomotion.

Rhythmical variations in blood cell flux in human skin have been studied using laser Doppler flowmetry. The fluctuations in blood cell flux could be divided into two different categories named alpha- and beta-oscillations with a median frequency of 6.8 min-1 and 1.5 min-1, respectively. The amplitude of beta-oscillations was approximately two to four times the amplitude of alpha-oscillations. Simultaneous registration from different skin regions showed periods with synchronous and non-synchronous fluctuations for both alpha- and beta-oscillations. alpha-oscillations were unchanged during local and ganglionic nerve blockade and were preserved in chronically sympathectomized tissue. In contrast, beta-oscillations disappeared completely after the three types of denervation. We suggest alpha-oscillations to be local non-neurogenic vasomotion and beta-oscillations to be a vascular reaction of pure neurogenic origin. A method for induction of regular amplified alpha-oscillations was discovered and evaluated. When heating the skin locally to 42 degrees C the blood cell flux increased and the pre-heating alpha- and beta-oscillations disappeared. During the post-heating period, amplified regular rhythmic alpha-oscillations appeared. At the end of the post-heating period beta-oscillations re-appeared.

Adult↗
PubMed1989

Effect of indomethacin on regulation of juxta-articular bone blood-flow during joint tamponade. An experimental study in puppies.

Prostaglandins are vasoactive substances which are assumed to play a major role in bone metabolism and bone repair. The purpose of the present study was to investigate the effect of indomethacin on the control of epiphyseal bone blood-flow. By means of simultaneous intra-osseous pressure (IOP) and regional blood flow (RBF) measurements in the distal femoral epiphysis (DFE), aspects of vascular control mechanisms in the distal femoral epiphysis were investigated during knee joint tamponade (50% of mean arterial pressure) before and after administration of indomethacin 7.5 mg/kg. Six dogs aged 3-4 months were investigated in fentanyl anaesthesia. Knee joint tamponade resulted in a significant increase in IOP and calculated venous resistance in the DFE, while no significant changes in regional blood-flow or arterial resistance were encountered. Administration of indomethacin did not affect this reaction. The results suggests that indomethacin 7.5 mg/kg does not influence the regulation of epiphyseal blood-flow during elevation of joint pressure indicating that prostaglandins play only a minor or no role in this regulation.

Animals↗
PubMed1988

The cause of ischaemic nocturnal rest pain.

Adipose tissue blood flow in the forefoot was measured simultaneously with mean systemic arterial blood pressure over 24 hours in 8 patients (15 feet) with different degrees of arterial insufficiency. Mean systemic arterial pressure decreased by 19 +/- 9% during sleep, irrespective of symptomatology. In two limbs, with a normal peripheral circulation, blood flow decreased by 8 +/- 7%. In five limbs with arterial insufficiency, but no rest pain, blood flow decreased by 16 +/- 8% and in eight limbs with ischaemic nocturnal rest pain blood flow was reduced by 32 +/- 12% during sleep. It is concluded that nocturnal hypotension is a major factor in the production of nocturnal ischaemic rest pain.

Aged↗
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

A pitfall in the measurement of arterial blood pressure in the ischaemic limb during elevation.

In order to evaluate if elevation of the ischaemic limb above heart level is an alternative to the conventionally applied method with external counterpressure for estimation of skin perfusion pressure, femoral and popliteal artery pressures were measured directly in eight patients with occlusion of the superficial femoral artery. The measurements were done in the horizontal position and during elevation of the calf above heart level. During elevation relative blood flow, measured by arterio-venous oxygen saturation differences, decreased compared with the horizontal position. In contrast the popliteal arterial pressure decreased only by 20% of the value expected from the degree of elevation of the calf above the level of the heart. Thus, it could be calculated that calf vascular resistance increased two- to three-fold on average during elevation. Four patients were reexamined with the venous pressure kept at 10 mmHg during elevation. In these patients, the increase in vascular resistance was significantly less compared with the situation in which venous pressure was 0 mmHg during elevation. The arterial pressure still did not decrease. It is concluded that perfusion pressure in the ischaemic lower extremity cannot be determined non-invasively by elevation of the extremity, probably due to collapse of segments of the vascular bed increasing the vascular resistance considerably.

Arteriosclerosis↗
PubMed1987

A comparison between 133Xenon washout technique and Laser Doppler flowmetry in the measurement of local vasoconstrictor effects on the microcirculation in subcutaneous tissue and skin.

Changes in skin blood flow measured by Laser Doppler flowmetry and changes in subcutaneous blood flow measured by 133Xenon washout technique were compared during activation of the local sympathetic mediated veno-arteriolar vasoconstrictor reflex by lowering the area of investigation below heart level. The measurements were performed in tissue with and without sympathetic innervation. In five subjects, who all had been cervically sympathectomized for manual hyperhidrosis, the Laser Doppler and 133Xenon blood flow measurements were performed simultaneously on the sympathetically denervated forearm, and on the calf with preserved sympathetic nerve supply. The Laser Doppler method registered a 23% reduction in skin blood flow during lowering of the extremities independently of the sympathetic nerve supply to the skin. The 133Xenon method recorded a 44% decrease in blood flow in innervated and unchanged blood flow in denervated subcutaneous tissue during lowering of the extremities. Our results indicate that the Laser Doppler method and 133Xenon method are not comparable, and that the Laser Doppler method is not useful in measuring local sympathetic mediated blood flow changes.

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

A pitfall in the evaluation of medical therapy for occlusive arterial disease using the xenon wash-out technique.

In a double-blind cross-over trial an oral thromboxane synthetase inhibitor (TSI) or placebo was given to 15 patients with severe foot ischaemia. After TSI therapy, rest pain remitted in nine out of 14 legs, while remission during placebo was seen in three out of 11 legs (NS). The ankle and toe systolic blood pressures remained constant during both study periods. Nocturnal adipose tissue blood flow in the forefoot was measured by the xenon wash-out method. A significant increase of the nocturnal perfusion rate constant during TSI therapy was found. A slight oedema developed during TSI therapy. This causes a change of the composition of the tissue under study and thus of lambda-xenon. The perfusion rate in the present study thus merely illustrates the latter and not a true increase in blood flow.

Adipose Tissue↗
PubMed1987

Impaired glucose-induced thermogenesis in skeletal muscle in obesity. The role of the sympathoadrenal system.

From a 7-day food recording in 29 morbidly obese patients two groups of six patients each were selected: a high-energy-intake group (HEI) and a low-energy-intake group (LEI). The groups were otherwise comparable. Five lean subjects served as controls for some observations. Oral glucose tolerance tests showed that all patients in the HEI group and the lean controls had normal glucose tolerance, whereas it was abnormal in all subjects in the LEI group. The fasting metabolic rate did not differ between the obese groups but was significantly lower in the lean group. The glucose-induced thermogenesis during 180 min expressed as a percentage of the energy content of the glucose load was lower in both obese groups compared with the lean controls (lean: +11.5 per cent, HEI: +5.3 per cent and LEI: -4.2 per cent, HEI vs lean: P = 0.04 and LEI vs lean: P = 0.005), and lower in the LEI group compared with the HEI group (P = 0.02). The integrated increase in leg oxygen consumption after glucose was also smaller in the LEI group than in the HEI group (15 +/- 269 vs 987 +/- 356 ml, P less than 0.05). The arterial noradrenaline response to glucose was significantly diminished in both obese groups compared with the lean controls. Glucose induced a similar increase in leg noradrenaline release in both obese groups, whereas the arterial adrenaline level was lower in the LEI group compared with the HEI group and with the lean controls (P = 0.04). Among the obese subjects the degree of glucose intolerance was inversely correlated with the post-glucose arterial adrenaline level (r = -0.55, and P = 0.04), and positively correlated with the fractional leg adrenaline extraction (r = 0.71, and P = 0.003). The results suggest that patients who are obese in spite of a fairly low energy intake have a reduced glucose-induced facultative thermogenesis, and that the defect is at least in part located in skeletal muscle. Since the sympathetic nervous system is partly responsible for the glucose-induced thermogenesis, the reduced thermogenic response in the obese patients may be due to an impaired activation of the sympathetic nervous system. It is hypothesized that the reduced arterial adrenaline level in the LEI group is caused by hyperglycaemic suppression of the adrenomedullary secretion and further that this may be a link connecting deterioration of glucose tolerance and a thermogenic defect in obesity.

Adrenal Glands↗
PubMed1987

Subcutaneous adipose tissue blood flow in the forefoot during 24 hours. Labeling pattern and reproducibility.

Wash-out of 133xenon from a local depot in the subcutaneous adipose tissue in the forefoot was measured continuously during 24 hours on subsequent recordings in 51 feet (normal circulation: 10, intermittent claudication: 22 and ischaemic nocturnal rest pain: 19) with a mean time interval of 26 days (range: 3-90 days). The patients were studied under two different conditions. Firstly, during the day in the erect position, awake (sitting, standing and quiet walking) and secondly, during night hours in the supine position, asleep. The coefficient of variation of nocturnal adipose tissue blood flow was calculated to 10%, and for the ratio of blood flow from day to night to 5%. The method is thus considered apt as a monitor in the treatment of peripheral vascular disease, for example, surgery and medical therapy. As predominant source of error is the formation of oedema.

Adipose Tissue↗
PubMed1987

Why do patients with severe arterial insufficiency get pain during sleep?

Simultaneous measurement during 24 h of mean arterial blood pressure (MABP) and forefoot subcutaneous adipose tissue blood flow (SBF) was undertaken in eight patients (15 feet) with different degrees of arterial insufficiency. The recordings were undertaken with the patients in the supine position only. The MABP decreased by 19 +/- 9% from awake to asleep independently of symptomatology. In two limbs with normal circulation, SBF decreased by 8 +/- 7%. In five limbs with arterial insufficiency but no rest pain SBF decreased by 16 +/- 8%, and in eight limbs with ischaemic nocturnal rest pain, SBF was reduced by 32 +/- 12% during sleep. It is concluded that nocturnal hypotension is the major aethiological factor for the symptom ischaemic nocturnal rest pain.

Adipose Tissue↗
PubMed1986

Inhibition of fatty acid mobilization by arterial free fatty acid concentration.

Subcutaneous, inguinal adipose tissue from dogs was perfused with blood in which the free fatty acid (FFA) concentration was varied corresponding to FFA/albumin molar ratios between 1 and 6. Otherwise the composition of the perfusate was kept constant. In order to stimulate lipolysis, isoprenaline and theophyllamine were added to the perfusate. A raise in arterial FFA/albumin molar ratio was without influence on lipolysis (as reflected in the release of glycerol), but reduced the FFA release indicating an increased re-esterification. At FFA/albumin ratios above 3 a marked increase in vascular resistance was seen. This increase was partly reversible within the time of a perfusion. When lipolysis is stimulated in the intact organism, the effects of increasing arterial FFA/albumin ratio on re-esterification and vascular resistance may serve as feedback mechanisms regulating FFA mobilization.

Adipose Tissue↗