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Biomedical subjects

E Stranden

Publications and source records attributed to E Stranden.

At least 37 records · Page 2Linked to original sources
PubMed1995

Insulin-mediated increase in calf blood flow is not related to blood pressure levels in patients with type 2 diabetes mellitus.

An association between insulin resistance and blood pressure levels has been found both in non-diabetic subjects and in type 2 diabetic patients. In non-diabetic subjects, infusion of insulin increases skeletal muscle blood flow, and it has been suggested that an attenuated flow-response to insulin may cause insulin resistance and may also serve as a mechanism relating insulin resistance to elevated blood pressure. We wanted to explore whether these findings could be extended to patients with type 2 diabetes. The effect of insulin infusion during a hyperinsulinaemic euglycaemic glucose clamp investigation on calf blood flow and its relationship to average diastolic blood pressure (DBPAVG), insulin sensitivity (GFRIlbm), body fat and total exercise capacity (TEC) was examined in 11 patients with type 2 diabetes. We found that insulin infusion increased median calf blood flow from 2.3 to 2.7 ml/min.100 g (p = 0.01). The change in blood flow (delta flow) did not correlate to the subjects' average blood pressure levels or their insulin sensitivity. Significant correlations between delta flow and leg fat %, fasting and clamp-insulin levels and total exercise capacity were observed. In conclusion, we found that insulin infusion increased calf blood flow significantly in patients with type 2 diabetes. However, our hypothesis that a negative correlation exists between blood pressure levels and insulin stimulated blood flow, was invalidated. Leg fat was identified as an important predictor of delta flow, GDRILBM and TEC in these patients.

Aged↗
PubMed1992

Chemical and radiological risk factors associated with waste from energy production.

We have tried to estimate the toxic potential of waste from nuclear power plants and from power plants burning fossil fuels. The potential risks have been expressed as 'risk potentials' or 'person equivalents.' These are purely theoretical units and represent only an attempt to quantify the potential impact of different sources and substances on human health. Existing concentration limits for effects on human health are used. The philosophy behind establishing limits for several carcinogenic chemicals is based on a linear dose-effect curve. That is, no lower concentration of no effect exists and one has to accept a certain small risk by accepting the concentration limit. This is in line with the establishment of limits for radiation. Waste products from coal combustion have the highest potential risk among the fossil fuel alternatives. The highest risk is caused by metals, and the fly ash represents the effluent stream giving the largest contribution to the potential risk. The waste from nuclear power production has a lower potential risk than coal if today's limit values re used. If one adjusts the limits for radiation dose and the concentration limit values so that a similar risk is accepted by the limits, nuclear waste seems to have a much higher potential risk than waste from fossil fuel. The possibility that such risk estimates may be used as arguments for safe storage of the different types of waste is discussed. In order to obtain the actual risk from the potential risk, the dispersion of the waste in the environment and its uptake and effects in man have to be taken into account.

Environmental Pollution↗
PubMed1992

Natural radiation--a perspective to radiological risk factors of nuclear energy production.

Radiation doses from natural radiation and from man-made modifications on natural radiation, and different natural radiological environments in the Nodic countries are summarized and used as a perspective for the radiological consequences of nuclear energy production. The significance of different radiation sources can be judged against the total collective effective dose equivalent from natural radiation in the Nordic countries, 92,000 manSv per year. The collective dose from nuclear energy production during normal operation is estimated to 20 manSv per year and from non-nuclear energy production to 80 manSv per year. The increase in collective dose due to the conservation of heating energy in Nordic dwellings is estimated to 23,000 manSv per year, from 1973 to 1984. An indirect radiological danger index is defined in order to be able to compare the significance of estimated future releases of radionuclides from a final repository of spent nuclear fuel to the consequences of natural radionuclides in different environments. The danger index of natural radiological environments will not be significantly increased by future releases of nuclear fuel radionuclides.

Hot Temperature↗
PubMed1992

The role of blood perfusion and tissue oxygenation in the postischemic transcutaneous pO2 response.

The transcutaneous pO2 (TCpO2) response following release of tourniquet cuff occlusion is expressed as oxygen reappearance time (ORT) and oxygen recovery index (ORI). In the present study the effects of blood perfusion and tissue oxygenation on ORT and ORI in healthy control subjects and two patient groups with peripheral arterial insufficiency were assessed. In control subjects, ORT reflects diffusion time for O2 molecules from capillaries to the TCpO2 sensor. In patients with claudication, ORT was prolonged probably because of delayed postischemic reperfusion and reduced tissue oxygenation. In patients with critical ischemia, prolonged ORT seems to be attributed more to reduced tissue oxygenation than to delayed postischemic reperfusion. ORI in control subjects and patients with claudication apparently depends more on capillary pO2 than on magnitude and duration of the postischemic reperfusion. In patients with critical ischemia, ORI is more related to decreased O2 delivery subsequent to reduced or absent reactive hyperemia response. In addition, increased O2 extraction ("O2 steal") and extensive countercurrent O2 exchange during low flow states may reduce ORT and ORI in severely ischemic skin.

Aged↗
PubMed1991

Local cold injuries sustained during military service in the Norwegian Army.

The series comprises 40 soldiers who sustained 49 local cold injuries during their service in The Norwegian Army. Twenty-one cold injuries were classified as first degree, 15 as second degree and 13 as third degree. No difference in ambient temperature at the time of injury was observed between the three categories of injuries, but the duration of cold exposure was significantly longer in those suffering third degree injury. Thirty-eight of the 40 soldiers experienced sequelae. The trend was that the severity of sequelae was most pronounced in third degree injuries. However, soldiers with first degree injury may suffer from significant sequelae, while those with third degree injury may exhibit a more benign clinical course. Overall degree of distress from sequelae was mild to moderate with exacerbation of symptoms and signs upon cold exposure. Although the influence on civilian occupational activity was minor, a substantial negative impact on performance in the field or combat setting may be anticipated. Soldiers as well as commanders must be thoroughly informed about prophylactic measures, symptoms and signs of an impending cold injury. Rewarming of the skin must be initiated without delay.

Adolescent↗
PubMed1991

The relation between changes in capillary morphology induced by ischemia and the postischemic transcutaneous pO2 response.

The postischemic transcutaneous pO2 response following release of tourniquet cuff occlusion is expressed as oxygen reappearance time (ORT) and oxygen recovery index (ORI). ORT and ORI have been assessed in patients with peripheral arterial insufficiency. The purpose of the present investigation was to study the relationship between capillary structure of the skin and ORT and ORI in patients with critical ischemia. ORT and ORI were measured when breathing ambient air and supplemental oxygen. The capillary morphology was studied and classified according to severity (capillary stage A, B or C) in the same ischemic area of the skin using vital capillary microscopy (VCM). ORT and ORI were assessed against the capillary morphology stages. Based on both VCM and transcutaneous pO2 (TCpO2) findings, patients could be separated into two groups. Group I had normal or minor changes of capillary morphology and significantly better ORT and ORI values than group II. Group II had poor ORT and ORI values, impaired response to breathing of supplemental oxygen and pathological capillary morphology. The results from this study indicate that major changes in capillary structure observed in critical ischemic skin may hamper O2 diffusion and modify both ORT and ORI. The influence of structural capillary changes on the TCpO2 parameters probably increases with the extent of morphological deterioration.

Aged↗
PubMed1990

Transcapillary forces in muscle compartments of lower limbs with deep venous thrombosis.

Interstitial fluid pressure (Pif), plasma- and interstitial fluid colloid osmotic pressures (COPpl, COPif) were measured in muscle compartments of the calf in lower limbs of patients with deep venous thrombosis (DVT) and in contralateral limbs. Pif was measured with the 'wick-in-needle' technique in the anterior and deep posterior compartments in three periods of time following start of treatment for DVT. The first period was from 0-24 h, the second from 24-48 h and the third later than 48 h. We found a significant increase in both muscular compartments in legs with DVT compared to the contralateral in the three periods except for Pif in the anterior compartment in the third period. A significant reduction of Pif in both muscular compartments of limbs with DVT was found when comparing the first and second periods but not from the second to the third period. No difference was found in Pif in the muscular compartments of the contralateral limbs between the three periods. Interstitial fluid for COPif measurements was obtained by inserting intravenous cannulas in the deep posterior muscle compartment of the calf of limbs with DVT and contralateral limbs. In oedematous tissue it was possible to collect some fluid, but this was almost impossible in the non-oedematous tissues of the contralateral limbs. COPif was 4.2(2.4) mmHg (mean(SD)) in the deep posterior compartment of limbs with DVT, which is probably significantly reduced. Increased Pif and reduced COPif indicate increased transcapillary fluid filtration and reduced reabsorption as the main cause of oedema in muscular compartments in DVT of the lower limbs.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1990

Transcapillary filtration in lower limbs with deep venous thrombosis; the role of the capillary filtration coefficient.

The capillary filtration coefficient (CFC) of the Starling equation was measured with strain gauge plethysmography at calf level of lower limbs with deep venous thrombosis (DVT). CFC was significantly elevated in limbs with DVT compared to the contralateral limb (0.0037(0.0005) ml min-1 100 g-1 mmHg-1 rise in filtration pressure and 0.0026(0.0010) ml min-1 100 g-1 mmHg-1 rise in filtration pressure, p less than 0.01) (Mean(SD]. Calf blood flow was also measured with strain-gauge plethysmography and was significantly increased in limbs with DVT compared to the contralateral (2.9(1.4)ml min-1 100 g-1 and 2.3(1.4) ml min-1 100 g-1, p less than 0.05). Increased venous pressure (Pv) found in lower limbs with DVT could be expected to lead to reduced blood flow. Our results point to an inflammatory reaction over-ruling increased venous resistance. No correlation was found between CFC and blood flow but this may have methodological explanations since increased Pv will influence both CFC and blood flow recordings obtained with plethysmography. Interstitial fluid hydrostatic pressure (Pif) measured with the 'wick-in-needle' technique in the deep posterior muscle compartment was significantly increased compared to the contralateral limb (6.3(3.5) mmHg and -1.2(3.4) mmHg, p less than 0.001). No correlation was found between CFC and Pif. Increase in CFC and blood flow at calf level is probably important in oedema in lower limbs with DVT.

Aged↗
PubMed1990

Mechanisms for edema formation in normal pregnancy and preeclampsia evaluated by skin capillary dynamics.

Disturbances of vasomotor activity and veno-arteriolar reflex mechanism probably promote cutaneous edema formation. Videophotometric capillaroscopy was used to measure nailfold skin capillary blood cell velocity (CBV) and its response to increased transmural pressure induced by venous occlusion in healthy subjects, normal pregnancies and patients with preeclampsia. Vasomotion, assessed by rhythmic variation of CBV, was also recorded. Both frequency (3-10 cycles/minute) and amplitude (0.01-0.23 mm/s) of CBV fluctuations were similar in all groups investigated. In healthy controls basal CBV was positively correlated with the amplitude of individual velocity fluctuations (r = 0.89). CBV response to venous occlusion was significantly reduced (p less than 0.05) in preeclampsia compared to normal pregnancies and non-pregnant controls. This finding indicates impaired veno-arteriolar reflex which may contribute to the edema formation seen in preeclampsia. It is suggested that vasomotor activity may serve as a physiological modulator of vascular resistance and hence CBV.

Adolescent↗
PubMed1989

Bilateral involvement and the effect of sympathetic blockade on skin microcirculation in the sympathetic dystrophies.

In a recent study we found skin capillary blood cell velocity (CBV) at rest, laser Doppler flux (LDF), and its response to lowering of the hand to be reduced in the dystrophic hand of patients suffering from sympathetic dystrophies. This study confirms these previous findings. Four of the 12 patients investigated felt intermittent pain in the "healthy" hand. Basal CBV, LDF, and reaction during dependency were not impaired in the asymptomatic hand compared with controls. However, during cooling of the contralateral hand CBV and LDF decreased significantly (median 44 and 37.5%) in the control group but neither in the affected nor in the asymptomatic hand among patients. Sympathetic blockade significantly increased both CBV and LDF in the dystrophic hand (median 58 and 20%), but no obvious beneficial symptomatic effect was noted. The lack of response to contralateral cooling in both hands indicates a disturbance of a central nervous mechanism in patients with unilateral sympathetic dystrophies.

Adult↗
PubMed1989

Skin capillary blood cell velocity in preeclampsia. The effect of plasma expansion.

Blood viscosity and peripheral vascular resistance have been reported to be increased in preeclampsia, indicating the possibility of an impaired capillary circulation. Nailfold skin capillary blood cell velocity (CBV) was measured by videophotometric capillaroscopy in 14 healthy pregnant women and 12 preeclamptic patients. No significant difference was found between basal CBV in the preeclamptic group (median 0.58 mm/s) and the healthy controls (0.52 mm/s). Following infusion of dextran 70 in preeclamptic patients CBV at rest increased to 154% of pre-infusion values (p less than 0.05). The time to peak CBV during post-occlusive reactive hyperemia was almost equal in the two groups and did not change in the preeclamptic group after dextran 70 administration. The enhanced dermal microcirculation following infusion of dextran 70 may be explained by hemodynamic and hemorheological effects, which presumably would be of greater importance if also present in the placental nutritive circulation.

Adult↗
PubMed1988

Laser Doppler flowmetry in evaluation of lower limb resting skin circulation. A study in healthy controls and atherosclerotic patients.

Laser Doppler flowmetry (LDF) was used to evaluate lower limb resting skin perfusion in sixty subjects divided into four groups: healthy young and elderly controls, and patients with intermittent claudication or critical ischaemia. Measurements were performed in pulp skin containing microvascular AV anastomoses and in the skin of leg and thigh where these shunts are absent. In toe pulp controls and claudicators had higher perfusion values than in leg and thigh skin (p less than 0.01), indicating that the LDF method evaluates flow both in nutritional capillaries, AV anastomoses and in dermal vascular plexa. Elderly controls had higher flux values in the pulp than claudicators (p less than 0.01), and claudicators had higher values than patients with critical ischaemia (p less than 0.01), showing that LDF could differentiate between the clinical groups. Study of reproducibility confirmed that values were reproducible on a given population. Day to day variation was considerable in individual subjects, probably because of changes in sympathetic vascular tone and because of different vascular architecture in the measuring volumes which are only some few mm3. The fact that LDF measures total skin blood flow explains why several papers have found a poor correlation between LDF and methods which mainly evaluate nutritional blood flow. The method is non-invasive, continuous and easy to perform. Laser Doppler flowmetry may have several clinical applications, like evaluating progress of atherosclerotic disease or therapeutic effects of drugs or operations. To increase the reproducibility of resting skin flux measurements local heating of the skin is recommended and the measurements should be performed with an integrating probe, which averages the readings obtained at several positions simultaneously.

Adult↗
PubMed1988

Skin microvascular circulation in the sympathetic dystrophies evaluated by videophotometric capillaroscopy and laser Doppler fluxmetry.

Finger-skin microcirculation and its reactions to sympathetic stimuli were investigated in 12 patients with sympathetic dystrophies, secondary to trauma or other diseases. Nailfold-skin capillary blood cell velocity (CBV) was measured by videophotometric capillaroscopy. Laser Doppler fluxmetry was used to provide an index of skin circulation in vessels in addition to the superficial capillaries. Both CBV and laser Doppler flux (LDF) values were significantly lower in the patients, compared with the healthy controls (P less than 0.05), despite the fact that skin temperature was the same in both groups. During cooling of the contralateral hand, CBV and LDF decreased markedly (22-60%) in the control group but not in the patients (0-13%). The decrease in skin perfusion normally seen upon lowering of the hand was also impaired in the patient group (7%) compared with controls (42%) (P less than 0.05). These impaired vasomotor reflex responses are consistent with sympathetic dysfunction and may well explain some of the typical features of the syndrome, e.g. limb oedema.

Aged↗