| 1. |
- Rosdahl, Hans, et al.
(författare)
-
Effect of physiological hyperinsulinemia on blood flow and interstitial glucose concentration in human skeletal muscle and adipose tissue studied by microdialysis
- 1998
-
Ingår i: Diabetes. - : American Diabetes Association. - 0012-1797 .- 1939-327X. ; 47:8, s. 1296-1301
-
Tidskriftsartikel (refereegranskat)abstract
- The effect of an euglycemic-hyperinsulinemic glucose clamp (94 +/- 5 microU/ml) on blood flow and glucose extraction fraction in human skeletal muscle and adipose tissue was investigated. Limb blood flow was measured by venous occlusion pletysmography and tissue blood flow by the microdialysis ethanol technique. Insulin infusion resulted in an increased blood flow in the calf and forearm (64 and 36%, respectively; P < 0.01) but not in the studied muscles of these limbs (ethanol outflow-to-inflow ratio: m. gastrocnemius 0.144 +/- 0.009 to 0.140 +/- 0.011, NS; m. brachioradialis 0.159 +/- 0.025 to 0.168 +/- 0.027, NS). This was accompanied by an increased extraction fraction of glucose, as measured by an increased arteriovenous difference over the forearm (0.16 +/- 0.04 to 0.70 +/- 0.10 mmol/l; P < 0.001) and by an increase in the estimated arterial-interstitial glucose difference in the gastrocnemius (0.82-1.42 mmol/l) and brachioradialis muscle (0.82-1.97 mmol/l). The blood flow in adipose tissue was significantly increased during insulin infusion, as evidenced by a decreased ethanol outflow-to-inflow ratio (0.369 +/- 0.048 to 0.325 +/- 0.046; P < 0.01). This was accompanied by an unchanged concentration of glucose in the dialysate (-2.6%, NS). In summary, during physiological hyperinsulinemia 1) a blood flow increase was detected in the calf and forearm, but not in the studied muscles of these limbs; 2) the blood flow increased in the subcutaneous adipose tissue; and 3) the estimated arterial-interstitial glucose difference increased in both muscles studied and was larger in the forearm muscle than the arteriovenous glucose difference over the forearm. The present study shows that microdialysis is a useful tool to obtain tissue-specific information about the effect of insulin on blood flow and glucose extraction in human skeletal muscle and adipose tissue.
|
|
| 2. |
- Lind, Lars, et al.
(författare)
-
Endothelium-dependent vasodilatation in treated and untreated hypertensive subjects
- 1999
-
Ingår i: Blood Pressure. - : Informa UK Limited. - 0803-7051 .- 1651-1999. ; 8:3, s. 158-164
-
Tidskriftsartikel (refereegranskat)abstract
- It has repeatedly been shown that endothelium-dependent vasodilatation (EDV) is impaired in patients with untreated hypertension. The effect of antihypertensive treatment on EDV has, however, not been extensively investigated. In the present study, EDV and endothelium-independent vasodilatation (EIDV) were studied in 20 untreated and 41 treated hypertensive subjects and in 26 matched, normotensive controls by means of infusion of methacholine (MCh), 2 and 4 microg/min, evaluating EDV, and nitroprusside (SNP), 5 and 10 microg/min, evaluating EIDV, in the brachial artery. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. The vasodilatory action of MCh was impaired in untreated hypertensives compared with controls, with the response in the treated hypertensives in between the other two groups (p < 0.01 vs both of the other groups). EIDV, on the other hand, was enhanced in the treated hypertensives (p < 0.01), so that the MCh to SNP FBF ratio, an index of endothelial function, was attenuated in both treated and untreated hypertensives (0.97 +/- 0.24 and 0.96 +/- 0.15, respectively), compared with controls (1.27 +/- 0.29, p < 0.001). Both EDV and EIDV declined with increasing number of antihypertensive drugs used in the treated hypertensives (p < 0.05). In conclusion, the endothelial function index was found to be similarly depressed in both treated and untreated hypertensive subjects compared with normotensive controls. Antihypertensive therapy seems to improve the vasodilatory capacity in general rather than enhancing endothelial function.
|
|
| 3. |
- Lind, Lars, et al.
(författare)
-
Endothelium-dependent vasodilation and structural and functional changes in the cardiovascular system are dependent on age in healthy subjects
- 1999
-
Ingår i: Clinical Physiology. - : Wiley. - 0144-5979 .- 1365-2281. ; 19:5, s. 400-409
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate possible associations between endothelium-dependent vasodilatation (EDV) and cardiovascular structure and function. EDV could influence peripheral resistance and be affected by atherosclerosis and might thereby influence indices of cardiovascular structure and function. In a group of 31 apparently healthy men and 25 women (age range 20-69 years), EDV was evaluated by infusion of metacholine (4 micrograms min-1), and endothelium-independent vasodilatation (EIDV) was assessed by nitroprusside infusion (SNP, 10 micrograms min-1) in the brachial artery. Forearm blood flow (FBF) was measured by venous occlusion plethysmography. Left ventricular (LV) geometry and function and the intima-media thickness in the carotid artery were assessed by ultrasonography. The stroke index to pulse pressure ratio was used to evaluate arterial compliance. Several indices of cardiovascular structure and function were found to be related to an index of endothelial function, the EDV to EIDV ratio. Furthermore, left ventricular mass (LVM), the atrio-ventricular plane displacement, E/A ratio, IVRT, the intima-media thickness of the carotid artery and arterial compliance were all significantly related to both EDV and EIDV in women. However, most indices of cardiovascular structure and function, as well as endothelial function, change with age and only the relation between LV diastolic function and endothelial function in men remained significant (P < 0.05) after including age in multiple regression analysis. Age was related to both cardiovascular structure and function, as well as to endothelial function. Multiple regression analysis showed that ageing generally affects cardiovascular characteristics and endothelial function in parallel in these healthy subjects.
|
|
| 4. |
- Sarabi, Mahziar, et al.
(författare)
-
Endothelin plays an important role in the endothelium-dependent vasodilatation in the human forearm
- 1999
-
Ingår i: Scandinavian Journal of Clinical and Laboratory Investigation. - : Informa UK Limited. - 0036-5513 .- 1502-7686. ; 59:1, s. 17-22
-
Tidskriftsartikel (refereegranskat)abstract
- Endothelium-dependent vasodilatation (EDV) in humans has been evaluated mainly by local infusion of a muscarinic-receptor agonists in the forearm. It has been postulated that the function of the vasodilator nitric oxide (NO) can be evaluated with this technique. However, the role of the vasoconstrictor endothelin in this model has not been investigated. METHODS: Ten male hypertensive and seven male normotensive subjects were subjected to measurements of forearm blood flow (FBF) by venous occlusion plethysmography during local intra-arterial infusion of metacholine (4 microg/min) or nitroprusside (10 microg/min). In parallel, forearm venous plasma endothelin (ir-ET) was determined. RESULTS: Metacholine and nitroprusside increased FBF 2.3 and 2.2 times the baseline level (6.6+/-2.8 SD ml/min/100 ml tissue) in hypertensive subjects and 5.1 times the baseline level (2.7+/-3.0 ml/min/100 ml tissue) for both drugs in the normotensive subjects. None of the drugs induced any significant changes in ir-ET levels in any of the groups (baseline 1.5+/-0.4 pmol/l in hypertensive and 1.1+/-1.2 pmol/l in normotensive subjects). However, in the hypertensive subjects, the individual change in venous ir-ET levels during infusion with metacholine, but not with nitroprusside, was inversely related to the degree of vasodilatation induced by this agent (r = -0.71, p < 0.02). A similar correlation coefficient (r=-0.69) was found in healthy subjects. CONCLUSION: Muscarinic-receptor-agonist-stimulated vasodilatation in the human forearm, thought mainly to reflect NO synthesis, was inversely related to the change in endothelin levels, suggesting an important role for this endothelium-derived vasoconstrictor in this model of EDV.
|
|
| 5. |
- Andersson, Per-Erik, et al.
(författare)
-
Regression of left ventricular wall thickness during ACE-inhibitor treatment of essential hypertension is associated with an increase in insulin mediated skeletal muscle blood flow
- 1998
-
Ingår i: Blood Pressure. - 0803-7051 .- 1651-1999. ; 7:2, s. 118-126
-
Tidskriftsartikel (refereegranskat)abstract
- Left ventricular hypertrophy (LVH) has been associated with insulin resistance, a condition with an impaired insulin-mediated vasodilation in skeletal muscle. ACE-inhibitors have been reported to be superior to most other antihypertensive drugs in inducing a regression of LVH. In a double-blind study with parallel groups, 50 patients with essential hypertension were randomized to treatment with either fosinopril (20 mg o.d.) or atenolol (50 mg o.d.) for 12-16 weeks. Left ventricle wall thickness (LVWT, defined as the sum of interventricular septum and posterior wall), diastolic function (represented by the ratio between the E-wave and the A-wave of mitral blood flow) and femoral artery blood flow (FBF) were evaluated using ultrasonic measurements. FBF was measured at normoinsulinemia and after 2 h of euglycemic hyperinsulinemia. Before treatment, the insulin-induced increase in FBF was inversely related to the LVWT (r = -0.52, p < 0.02). The reduction in ambulatory 24-h SBP/DBP was 13/9 mmHg for fosinopril and 15/14 for atenolol, ambulatory DBP being significantly more reduced by atenolol (p = 0.03 for difference in treatment effect). However, only fosinopril treatment resulted in a significant reduction in LVWT (from 20.5 mm to 19.4 mm, p < 0.05). The degree of reduction in LVWT was related to the increase in FBF in the fosinopril group (r = -0.45, p < 0.05). For fosinopril (but not for atenolol), there was a positive relationship between the change in E/A ratio and the change in femoral artery stroke volume (r = 0.80, p < 0.01). Conclusion: Impaired insulin-induced stimulation of leg blood flow was related to an increased LVWT. Furthermore, during fosinopril treatment, regression of LVWT was associated with enhanced skeletal muscle blood flow during hyperinsulinemia. This indicates that impaired peripheral blood flow (and thereby increased afterload) may be a possible mechanism explaining the previously found association between insulin resistance and cardiovascular hypertrophy.
|
|
| 6. |
|
|
| 7. |
|
|
| 8. |
- Carlstedt, F., et al.
(författare)
-
Serum levels of parathyroid hormone are related to the mortality and severity of illness in patients in the emergency department
- 1997
-
Ingår i: European Journal of Clinical Investigation. - : Wiley. - 0014-2972 .- 1365-2362. ; 27:12, s. 977-981
-
Tidskriftsartikel (refereegranskat)abstract
- Hypocalcaemia is a common finding in intensive care patients. In addition, raised levels of parathyroid hormone (PTH) have been described. The explanation and clinical importance of these findings are yet to be revealed. To investigate the occurrence of hypocalcaemia and elevated PTH levels and their relationship to morality and the severity of disease, serum levels of PTH, ionized calcium (Ca2+) and the cytokines interleukin 6 (IL-6) and tumour necrosis factor alpha (TNF-alpha) were measured on arrival in the emergency department in a broad spectrum of 140 acutely ill patients patients suffering from common diseases such as stroke, acute abdominal disorders, obstructive lung diseases, heart failure, acute myocardial infarction, angina pectoris, trauma and infectious diseases. A score (APACHE II) was calculated to assess the severity of disease. Elevated PTH levels (> 55 pg ml-1) were seen in 16% of the patients, being most frequent in patients with myocardial infarction (28%) and congestive heart failure (42%). The levels were significantly correlated with the APACHE II score (r = 0.48, P < 0.0001) and with the length of stay in hospital (r = 0.26, P < 0.002). PTH was also significantly (P < 0.03) elevated in non-survivors compared with survivors and was found to be a stronger predictor of mortality (P < 0.01) than the APACHE II score (P < 0.02) in Cox's proportional hazard analysis. No close relationships were found between the cytokine levels and the indices of calcium metabolism. In conclusion, a rise in serum levels of PTH was common and related to the severity of disease and mortality in a mixed emergency department population.
|
|
| 9. |
- Fugmann, Andreas, et al.
(författare)
-
The effect of euglucaemic hyperinsulinaemia on forearm blood flow and glucose uptake in the human forearm
- 1998
-
Ingår i: Acta Diabetologica. - : Springer Science and Business Media LLC. - 0940-5429 .- 1432-5233. ; 35:4, s. 203-206
-
Tidskriftsartikel (refereegranskat)abstract
- Insulin-mediated stimulation of blood flow to skeletal muscle has been proposed to be of major importance for insulin-mediated glucose uptake. The aim of this study was to investigate the relative importance of blood flow and glucose extraction as determinants of insulin-mediated glucose uptake in the human forearm. Forearm blood flow (FBF), glucose extraction and oxygen consumption were evaluated for 100 min during the euglycaemic hyperinsulinaemic clamp (92 mU/l) in nine healthy subjects. FBF was measured by venous occlusion plethysmography. Forearm glucose uptake increased sevenfold during the hyperinsulinaemia (P<0.001). Forearm glucose extraction showed a minor increase during the first 10 min of hyperinsulinaemia, but the most marked increase took place between 10 and 20 min (+170%). Thereafter, only a minor further increase was seen. During the first 10 min of hyperinsulinaemia FBF was unchanged. Thereafter, FBF increased steadily to a plateau reached after 60 min (+50%, P<0.001). A close relationship between whole body glucose uptake and FBF was seen at the end of the clamp (r = 0.75, P<0.02), but at this time the relationship between whole body glucose uptake and forearm glucose extraction was not significant. The modest increase in O2 consumption seen at the beginning of the clamp (+19%) was not related to FBF during the early phase of the clamp. In conclusion, the early course of insulin-mediated glucose uptake in the human forearm was mainly due to an increase in glucose extraction. However, with time the insulin-mediated increase in blood flow increased in importance and after 100 min of hyperinsulinaemia FBF was the major determinant of glucose uptake.
|
|
| 10. |
|
|
