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Biomedical subjects

B Fagrell

Publications and source records attributed to B Fagrell.

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

Vital microscopy and the pathophysiology of deep venous insufficiency.

Insufficiency of the deep venous system of the leg may cause severe disturbances of the skin microcirculation. The pressure in the deep venous system increases markedly during walking when the venous valves are destroyed. This pressure increase is transmitted out through the ankle perforators into the superficial veins of the skin, causing a marked pressure increase in the skin microcirculation, interfering with the normal nutritional circulation. In patients with only superficial venous incompetence, the number of capillaries is unchanged, and the configuration mostly normal. When the capillary pressure is markedly increased, blood components are pressed out through the capillary wall and deposited between the wall and the skin cells. By ordinary capillary microscopy this can be seen as light areas around the capillaries. The capillaries themselves become very enlarged and tortuous, and the number is decreased. One of the most striking findings is the appearance of a < > formation around the nutritional skin capillaries. This halo is caused by a specific microedema which can be demonstrated by microscopic techniques. The edema fluid seems to contain high concentrations of fibrin, other proteins and neutral polysaccharides. The development of the halo formation is most probably due not only to incompetence of the venous but also of the lymphatic system of the affected leg. The normal pathway of nutrients from the capillaries out to the skin cells will be blocked by the oedema, and skin ulcers develop. The good effectiveness of compression bandaging in venous leg ulcers can be explained by a marked reduction of the edema, facilitating the transport of nutrients from the capillaries to the skin cells.

Capillaries↗
PubMed1994

Mental stress induces different reactions in nutritional and thermoregulatory human skin microcirculation: a study in borderline hypertensives and normotensives.

It has recently been shown that the reactivity of total (= thermoregulatory) and nutritional (= capillary) skin microcirculation differs in hypertension and normotension (NT) with a reduced stress response in hypertension. The present study investigated skin microcirculation in 40 patients with borderline hypertension (BHT) and 38 NT controls. Capillary blood flow (CBV, dynamic capillaroscopy) and subpapillary thermoregulatory flow (Laser Doppler fluxmetry, LDF) was measured at rest, after arterial occlusion and during and after a mental stress test. Resting CBV (0.48 vs. 0.50 mm/s) and LDF (3.19 vs. 3.06 AU) were equal in the two groups and no difference was found in postocclusive hyperaemia response. Reactivity to mental stress was similar in both groups with a significant increase in LDF (45% and 39%) and a significant decrease in CBV (35% and 30%). In nonsmokers the BHT group tended to increase less in LDF (50% vs. 72%) and decrease slightly more in CBV (35% vs. 28%) than the NT group. No such difference was seen in smokers. Mental stress induces opposite reactions in total and nutritional skin microcirculation both in borderline hypertensives and normotensives. There were no significant differences in reactivity between the two groups, possibly due to the alleviated responses seen in smokers in both groups.

Adult↗
PubMed1993

Level of arterial obstruction in patients with peripheral arterial occlusive disease (PAOD) determined by laser Doppler fluxmetry.

AIM: To evaluate the laser Doppler fluxmeter as a non-invasive screening method to determine the level of peripheral arterial occlusive disease (PAOD) in the lower limb. DESIGN: Open study of the veno-arterial reflex (VAR) during a shift in body position using a laser Doppler fluxmeter at five probe positions distal to the knee, compared with the occlusion level determined by arteriography and segmental plethysmography. MATERIALS: 50 legs comprising 10 normal controls, 20 legs with suprainguinal obstructions (10 claudication and 10 critical ischaemia) and 20 legs with infrainguinal obstructions (10 claudication and 10 critical ischaemia). RESULTS: Controls had normal VAR (mean flux reductions of 38% during dependency) at all probe positions. Legs with infrainguinal disease had normal reflexes proximally but significantly disturbed reflexes distally, whereas suprainguinal disease showed alterations at all sites. Claudicants had diminished flux reduction (mean 12%) whilst those with critical ischaemia increased the flux (mean 32%). CONCLUSION: This simple, non-invasive technique may be of use in determining the level of obstruction in PAOD.

Aged↗
PubMed1993

Skin microcirculation in neonatal polycythaemia and effects of haemodilution. Interaction between haematocrit, vasomotor activity and perfusion.

The cutaneous microcirculation was investigated before and 2-4 h after haemodilution in 13 newborn infants with polycythaemia. Skin microvascular perfusion was related to the haematocrit and to the presence of rhythmical changes in blood flow, reflecting vasomotor activity. The microcirculation was studied with a laser Doppler fluxmeter in a superficial microvascular bed represented by the dorsal hand skin. In five subjects, it was possible to combine laser Doppler flux measurements with microscopic quantitations of blood cell velocity in single, nailfold capillaries. In neonates less than 12 h postnatal age (n = 6), microvascular perfusion was only one-third that of the equally polycythaemic, but older infants (n = 7, p < 0.01). The higher perfusion in the older neonates with polycythaemia was associated with rhythmical variations in blood flow (3-5 cycles/min). There was no difference in skin temperature, blood pressure or heart rate between the two age groups. After haemodilution, the younger infants had developed rhythmical blood flow variations with the same characteristics as in the older group, in which the flow pattern was unchanged. In association, the laser Doppler flux had increased 304% in the younger and 73% in the older group (median values, p < 0.05 versus pretreatment values). The post-treatment change in laser Doppler flux corresponded to an increase in nailfold capillary blood cell velocity from 0.08 (0.02-0.23) mm/s prior to haemodilution to 0.21 (0.07-0.32) mm/s after treatment (n = 5, p < 0.05). Skin microcirculatory effects of neonatal polycythaemia and haemodilution vary in relation to vasomotor activity.

Aging↗
PubMed1993

Low molecular weight heparin seems to improve local capillary circulation and healing of chronic foot ulcers in diabetic patients.

Ten diabetic patients with peripheral arterial occlusive disease, peripheral polyneuropathy and chronic foot ulcers were given 2500 U low molecular weight heparin (Fragmin, Kabi-Pharmacia AB, Sweden) subcutaneously once a day during 8 weeks. The mean age was 63 (47-80) years and the mean duration of foot ulcers 8 (4-12) months. All patients had previously received conventional treatment during 12 weeks, without any noticeable improvement on ulcer healing. The ulcer area was measured, and the skin microcirculation of the forefoot and around the ulcers was investigated before, during and after treatment with Fragmin. The total skin microcirculation was measured by laser Doppler fluxmetry, the nutritional skin microcirculation by vital capillaroscopy and the macrocirculation by determination of the ankle/arm pressure ratio. The ulcer area decreased significantly in eight patients of which four healed the ulcers completely. Of the remaining two patients one deteriorated, whereas one showed a decrease of the ulcer area during treatment, but an increase when treatment was stopped. The macro- and total microcirculation were unchanged in all patients, whereas the nutritional capillary circulation improved in seven out of nine patients, concomitantly with clinical improvement. The biological zero value (a flow-independent part of the LD signal) was high in 4 patients before treatment, but decreased during treatment and remained low even after treatment with Fragmin.-The results indicate that Fragmin positively influences the healing process of chronic foot ulcers in diabetic patients, possibly by improving the capillary circulation in the ulcer margin, in spite of an unchanged arterial and total skin microcirculation of the region.

Adult↗
PubMed1992

An evaluation of skin capillary blood flow determinations in neonates using a computerized videophotometric method.

Dynamic capillaroscopy has been shown to give valid measurements of skin capillary blood flow in adults. The aim of this investigation is to evaluate the accuracy of the method when applied to studies in newborn infants. A computerized videophotometric technique was used to measure the skin capillary blood cell velocity (CBV) and the capillary erythrocyte column diameter at 64 standardized locations in 16 nailfold capillaries in five subjects. To estimate the method's reliability, we calculated the coefficient of variation (CV = 1 SD/mean x 100%) for repeated measurements at each location. The CV for CBV determinations was found to be 3.4% (0.9-13%) and the corresponding value for capillary diameter measurements was 6.7% (0.5-12%) (median and range). Although the CBV and diameter values were found to vary along the course of the capillary, the volume flow of blood cells was assumed to be the same in simultaneously studied but different sections of the capillary. The paired CBV and diameter observations were therefore used to calculate blood cell flow values at an average of four different intracapillary locations. To estimate the method's validity, the CV for these repeated flow calculations was determined and found to be 7.5% (3.2-26%). We conclude that the age-specific characteristics in neonates, mainly a high hematocrit and short, irregular skin capillary loops, do not limit the feasibility and accuracy of videophotometric microscopy for dynamic microcirculatory studies in neonates.

Capillaries↗
PubMed1992

Effects of neonatal polycythemia and hemodilution on capillary perfusion.

The effects of neonatal polycythemia on nutritive capillary perfusion were investigated by a television microscopy technique. The capillary blood flow velocity in skin was measured in 12 neonates with polycythemia before and after treatment with hemodilution, and in 13 healthy control infants. The capillary blood flow velocity in the patients was 0.11 (0.02 to 0.34) mm/sec and in the healthy control infants 0.30 (0.17 to 0.44) mm/sec (p less than 0.01, median and range values). In relation to the absolute hematocrit change after treatment range, -20% to 0%), the capillary blood flow velocity increased nonlinearly (range, +733% to -14%; r = -0.98; p less than 0.001). The postnatal age was found to contribute significantly to the variation in results--the neonates with polycythemia studied during the first day of life had a very slow skin capillary circulation and responded to treatment with a more pronounced increase in capillary blood flow velocity than did the older patients. This in vivo model for capillary perfusion indicates that an insufficient microcirculation may be involved in the pathophysiology responsible for the morbidity associated with neonatal polycythemia.

Age Factors↗
PubMed1992

Hyperleukocytic effects on skin capillary circulation in patients with leukaemia.

A decrease in capillary flow due to hyperleucocytosis may cause impairment of organ perfusion in patients with leukaemia. In order to evaluate the effects of different cell types of leukaemic cell origin on skin capillary circulation we have studied patients with (a) chronic lymphocytic leukaemia (CLL) (n = 6) and (b) acute non-lymphocytic leukaemia (ANLL) (n = 6) or chronic granulocytic leukaemia (CGL) (n = 5). Capillary blood cell velocity (CBV) in fingernail-fold capillaries was measured by videophotometric capillaroscopy. After a 1-min arterial occlusion at the finger base, the post-occlusive reactive hyperaemia was evaluated by measuring the peak (p) CBV and the time to pCBV. In patients with ANLL/GGL, both resting CBV and pCBV were lower than in healthy control subjects. In the CLL patients these values were not significantly different compared to controls. In a few patients the time to pCBV was markedly prolonged. Symptoms attributable to hyperviscosity were more common in patients with ANLL/CGL and low CBV values. It is suggested that the cell size of leucocytes may be an important factor in the development of hyperviscosity syndromes and organ malperfusion in leukaemic patients.

Adult↗
PubMed1992

Effects of oxygen inhalation on skin microcirculation in patients with peripheral arterial occlusive disease.

BACKGROUND: Oxygen administration is currently used in clinical medicine to improve peripheral oxygen delivery to tissues threatened by ischemia. However, conflicting results have been reported on the effects of oxygen in ischemic areas. This study was aimed at investigating the effects of 40% oxygen inhalation on the skin microcirculation in the feet of patients with peripheral arterial occlusive disease (PAOD). METHODS AND RESULTS: Transcutaneous oxygen tension (tc PO2) was measured on the dorsal skin of the foot, and the nailfold microcirculation was investigated by a combination of laser Doppler flowmetry (LDF) and dynamic capillaroscopy (CBV) in the great toes of 17 legs of 11 patients, with 13 legs of eight normal subjects as a control group. Inhalation of oxygen induced a significant decrease of both the total (delta LDF, -307%, p less than 0.02) and nutritional (delta CBV, -17%, p less 0.002) skin microcirculation in normal legs compared with baseline values. A similar response was observed in 10 legs of patients who showed a significant increase of the tc PO2 (greater than or equal to 10 mm Hg) (delta LDF, -14%, NS; delta CBV, -13%, p less than 0.005). By contrast, both the total (+21%, p less than 0.03) and nutritional (+52%, p less than 0.05) circulation significantly increased in the seven legs without significant tc PO2 increase. In addition, the flow motion, which was impaired in the patients, was significantly (p less than 0.05) improved by oxygen inhalation. CONCLUSIONS: Inhalation of 40% oxygen induces a vasoconstriction in the skin microcirculation of toes of the normal subjects and patients with moderate PAOD but induces an increase of the skin microcirculation in patients with severe PAOD.

Administration, Inhalation↗
PubMed1992

Effects of local hyperemia and edema on the biological zero in laser Doppler fluxmetry (LD).

The method of laser Doppler (LD) fluxmetry records the flux of moving blood cells and particles in a small tissue volume. However, also during complete arterial occlusion a flux-independent signal can be recorded, which is sometimes significantly different from the electrical zero of the instrument. This part of the signal has been called the biological zero (BZ), and can sometimes represent up to 80% of the total LD signal. In the present study, we investigated the influence of induced hyperemia produced by methylnicotinate and histamine respectively, both vasodilators but only histamine giving edema. Eleven legs of nine healthy subjects were studied. Test sites on the dorsal skin of the foot were prepared with a) histamine (10 mg/ml), b) methylnicotinate (0.1 mol/l) and c) saline. The substances were administered onto the skin with a lancet as the prick test procedure. The basal LD was measured before, and the BZ during an arterial occlusion obtained with a cuff at the ankle. Histamine induced a wheal and edema in all subjects, while methylnicotinate only caused erythema. Basal LD was significantly (p less than 0.01) increased by both substances compared to saline. The BZ was significantly higher (p less than 0.01) with histamine than with both saline and methylnicotinate. The results show that BZ is increased by vasodilation, and still more so by edema formation. It is concluded that the BZ value must always be recorded and taken into consideration when LD blood cell flux is measured in the skin.

Adult↗
PubMed1992

Effects of sympatho-adrenal activation on the finger microcirculation in mild hypertension.

Finger skin circulatory responses to three forms of sympatho-adrenal activation were investigated in 14 patients with mild hypertension and 14 matched normotensive controls. Finger nailfold skin capillary blood cell velocity was measured by video-photometric capillaroscopy and finger pulse volume by strain-gauge plethysmography (digital arterial pulse amplitude; DAPA). DAPA decreased more markedly in the normotensive as compared with the hypertensive group during mental arithmetic stress (38 vs. 19%; P less than 0.05) and a cold pressor test (55 vs. 32%; P less than 0.05). Intravenous infusions of adrenaline (0.1-0.8 nmol/kg/min) decreased DAPA in normotensives but not in hypertensives (P less than 0.05). Capillary blood cell velocity was similar in the two groups at rest and decreased promptly and to a similar extent in both groups following mental arithmetic, adrenaline infusion and the cold pressor test (by approximately 60, 60 and 35%, respectively). It is concluded that mental stress and the cold pressor test induce instantaneous and marked effects on the skin circulation via neurogenic activation. The less marked effect on DAPA in the hypertensive group may reflect an elevation of basal vascular tone and/or early structural vascular changes in mild hypertension. The discrepancy between total finger and capillary circulatory responses to adrenaline may be attributable to different adrenoceptor populations and/or sensitivity in arteriovenous shunts, as compared with precapillary vessels.

Adrenal Glands↗
PubMed1991

Skin microvascular reactivity in fingers of diabetic patients after combined kidney and pancreas transplantation.

Nine patients with severe late diabetic complications were investigated 2 and 38 months after successful combined kidney and pancreas transplantation. Nine healthy subjects served as controls. Blood cell velocity in single capillaries was evaluated by videophotometric capillaroscopy, and total skin microcirculation of the same area by laser Doppler fluxmetry. The measurements were performed during rest, and post-occlusive (1 min) reactive hyperaemia. Laser Doppler flux was also recorded during venous occlusion. The basal capillary blood cell velocity and laser Doppler flux values increased significantly (p less than 0.05) during the observation period. The time to maximal capillary blood cell velocity during hyperaemia was prolonged 2 months after combined kidney and pancreas transplantation (p less than 0.05), and still more so at 38 months (p less than 0.05). The ability to decrease blood flow during venous occlusion was impaired at 2 months, and was not significantly better at reinvestigation. The results indicate a succesive increase of basal blood flow in the skin microcirculation after successful combined kidney and pancreas transplantation, but no improvement of the impaired microvascular reactivity.

Adult↗
PubMed1991

Reactive hyperemia in term neonates and adults--a laser Doppler fluxmetry study of skin microcirculation.

The reactivities of neonatal and adult microcirculation have been studied and compared. The cutaneous reactive hyperemia after 1 and 4 min of arterial occlusion (AO) was measured with a laser-Doppler fluxmeter in 21 healthy neonates and 10 adults. Local skin temperature, mean arterial blood pressure (MAP), and skin prick hematocrit were also determined at the same time. The magnitude of neonatal reactive hyperemia was approximately one-third that of the adult response regardless of the duration of AO. In both groups, with age-specific regressions, the hyperemic blood flow response after 4 min of AO developed more slowly in subjects with low MAP and was of low magnitude in subjects with high hematocrit values. In response to a prolongation of AO, from 1 to 4 min, the magnitude and duration of hyperemia increased significantly and similarly in both neonates and adults. We conclude that compared to adults neonates have a less pronounced ability to increase skin microcirculation in response to local ischemia. The normally low blood pressure and high hematocrit in newborn infants contribute further to this conclusion.

Adult↗
PubMed1991

Evaluation of the dynamic cutaneous post-ischaemic hyperaemia and thermal response in elderly subjects and in an area at risk for pressure sores.

The response of skin blood cell flux (SBF) to locally applied pressure was evaluated with the laser-Doppler technique in the areas of the sacrum and the gluteus maximus muscle of geriatric patients and healthy young and elderly subjects. The SBF over the sacrum stopped at a lower external skin pressure than over the gluteus muscle in all groups studied (P less than 0.05-0.001). The SBF at rest was lower among geriatric patients and over the sacrum, with men showing the lowest value (P less than 0.001). The initial slope of the SBF curve and the peak SBF during the post-occlusive reactive hyperaemia (PRH) were lower among geriatric patients compared to younger healthy subjects (P less than 0.05-0.01) over both areas studied. During the last part of the PRH response rhythmic oscillations started, known as vasomotion. The mean skin temperature at rest was higher over the sacrum (P less than 0.001) than over the gluteus area, but no difference was found between the groups. The temperature increase during the PRH was larger over the gluteus muscle (P less than 0.01) than over the sacrum area in the healthy subjects. Among the patients the temperature increase was larger over the gluteus only during the first half of the PRH, after which the temperature increased most over the sacrum. It is concluded that SBF and skin temperature show different responses in microvascular reactivity to external pressure in elderly vs. younger subjects and also between sexes. The described technique may be useful in clinical practice for predicting the risk of pressure sores in different areas and subjects.

Adult↗