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Biomedical subjects

U Ewald

Publications and source records attributed to U Ewald.

At least 55 records · Page 3Linked to original sources
PubMed1992

Cutaneous blood flow during a hypoglycaemic clamp in insulin-dependent diabetic patients and healthy subjects.

1. A marked cutaneous vasodilatation has been shown to occur in healthy subjects, but not in insulin-dependent diabetic patients, in response to hypoglycaemia induced by a rapid intravenous bolus injection of insulin. 2. In the present study cutaneous blood flow in response to a gradual decline in blood glucose concentration was investigated in eight young adult diabetic patients and in eight age- and sex-matched control subjects. After a hyperinsulinaemic euglycaemic clamp for 40 min, hypoglycaemia was induced (plasma glucose concentration 2 mmol/l) by a standardized stepwise reduction in the intravenous glucose infusion. 3. Blood flow was measured by using a laser Doppler sensor and a cutaneous O2 electrode placed on the medial aspect of the forearm, and a laser Doppler sensor placed on the forehead. 4. No significant change in cutaneous blood flow occurred during euglycaemic hyperinsulinaemia. 5. In control subjects a marked increase in blood flow during hypoglycaemia was observed in the forearm by both methods. No corresponding change was observed in the forehead. 6. In the diabetic patients the increase in cutaneous blood flow was absent in both the forearm and forehead. 7. It is concluded that hypoglycaemia, but not hyperinsulinaemia, is associated with a regional cutaneous vasodilatation in healthy control subjects. This cutaneous vasodilatation is absent in diabetic patients.

Adult↗
PubMed1992

Neonatal septicemia caused by pneumococci.

Pneumococci (Streptococcus pneumoniae) infrequently cause neonatal septicemia. An increased number of cases have been reported in recent years, but no increase in the relative incidence among neonatal infections has been noted. On the basis of two cases of our own and a review of 40 recently published case reports, the clinical characteristics of pneumococcal septicemia are described and the pathogenesis is discussed. The presenting clinical picture in early-onset pneumococcal septicemia is dominated by respiratory distress, frequently accompanied by leukopenia, and is indistinguishable from that seen in septicemia caused by Group B Streptococci (GBS). The onset is preceded by prelabor rupture of the fetal membranes in almost half of the instances. The mortality is 50%, twice the figure given in recent GBS reports.

Disease Outbreaks↗
PubMed1992

Two cases of neonatal pneumococcal septicemia.

Pneumococci (Streptococcus pneumoniae) infrequently cause neonatal septicemia. An increased number of cases have been reported in recent years, but no increase in the relative incidence among neonatal infections has been noted. Two recent cases that occurred within a short period of time are described. They were found to exhibit most clinical characteristics, previously described, of Group B Streptococci (GBS) septicemia with an early onset, but appear to have a graver prognosis.

Adult↗
PubMed1991

Gestational diabetes-perinatal outcome with a policy of liberal and intensive insulin therapy.

During 3 years of continuous screening for gestational diabetes mellitus in the county of Uppsala, 133 pregnant women (1.2%) were given this diagnosis. Maternal characteristics and the perinatal outcome of the pregnancies were examined retrospectively. Maternal overweight [body mass index greater than 23.9 kg/(m)2] was noted in 54.9% of the 133 women. Insulin therapy, with a mean daily dose of 42 U, was given to 62.4% of the patients, whereas the others were given dietary instructions alone. The frequency of infants with a birth weight greater than 2 SD was 24.1% and was significantly (p less than 0.025) related to pre-pregnancy overweight and also to pregnancy weight gain 18kg (p less than 0.01). Caesarean section was performed in 27% of the pregnancies complicated by diabetes, compared with the overall figure of 11% in Uppsala during the study period. Neonatal hypoglycaemia (blood glucose greater than or equal to 1.6 mM) was noted in 17.3% of the infants and was significantly (p less than 0.01) related to maternal sympathomimetic therapy. Despite liberal and intensive insulin therapy, there was a considerable rate of perinatal complications. Although not severe, they indicate a need for further improvement in the care of women with gestational diabetes.

Diabetes, Gestational↗
PubMed1990

Prostacyclin-like activity in umbilical arteries is dose-dependently reduced by maternal smoking and related to nicotine levels.

The influence of maternal smoking on the formation of prostacyclin-like activity in human umbilical arteries was studied in 84 unselected term deliveries. In arteries from infants of nonsmoking mothers the prostacyclin-like activity measured by a bioassay technique amounted to 81 +/- 37 ng/g (mean +/- SD), and in those from smokers to 67 +/- 35 ng/g (p less than 0.05). When smokers were divided into those smoking 10 cigarettes daily or more and those smoking 1-9 cigarettes per day, only arteries of infants of the heavier smokers showed a significantly reduced prostacyclin-like activity (56 +/- 27 ng/g; p less than 0.02). Nicotine and cotinine levels were weakly inversely correlated to prostacyclin-like activity (p less than 0.05). Reduced prostacyclin production in umbilical arteries implies reduced capacity for vasodilation and lowered defence against fetal hypoxia in heavy smokers.

Adenosine Diphosphate↗
PubMed1990

Lack of cutaneous hyperemia in response to insulin-induced hypoglycemia in IDDM.

Cutaneous blood flow was measured with the laser Doppler technique and by recording cutaneous O2 tension on the forearm and forehead in nine young adult patients with insulin-dependent diabetes mellitus (IDDM) and nine sex- and age-matched healthy control subjects after induction of hypoglycemia. In the healthy subjects, cutaneous blood flow measured with the laser Doppler technique was increased by 120 +/- 26% in the forehead (P less than 0.01) and 196 +/- 50% in the forearm (P less than 0.01) at the glucose nadir (blood glucose 1.8 +/- 0.2 mM) compared with basal blood flow. In contrast, in diabetic patients, cutaneous blood flow was unchanged. The corresponding changes, at the glucose nadir, with cutaneous O2 tension recordings were 286 +/- 131% (P less than 0.05) in control subjects and -22 +/- 15% (NS) in diabetic patients. An impairment of sympathetic nervous function, not detectable by simple cardiovascular tests, could be responsible for the lack of cutaneous hyperemia and sweating and could contribute to unawareness of hypoglycemia in diabetic patients.

Adult↗
PubMed1989

Platelet aggregability during the first two years of type 1 (insulin-dependent) diabetes mellitus in children.

Platelet aggregation in response to collagen, adenosine diphosphate and arachidonic acid was studied prospectively in 30 children with Type 1 (insulin-dependent) diabetes mellitus. The studies began on admission to hospital and continued throughout the two years following diagnosis. The results were compared with those in 44 health control children. Collagen-induced aggregation was significantly decreased in the diabetic children on admission in comparison to the healthy children. In contrast, the aggregation induced by adenosine diphosphate (1.1 mumols/l, p less than 0.05) and arachidonic acid (0.25 mmol/l, p less than 0.05) was increased on admission. The magnitude of the platelet shape change after adenosine diphosphate stimulation was small at the onset of the disease but was significantly increased towards normal during the two years of follow-up. On admission, the primary wave aggregation induced by adenosine diphosphate was positively and significantly correlated to some of the lipoprotein fractions that were disturbed at that time, especially triglycerides in high-density lipoproteins. After two years of treatment the platelet aggregability in the diabetic children had been restored to normal.

Adenosine Diphosphate↗
PubMed1988

Circulating class II transplantation antigen-expressing T lymphocytes in children with insulin-dependent diabetes mellitus at diagnosis.

The occurrence of circulating class II antigen-expressing T lymphocytes was examined in 25 children with insulin-dependent diabetes mellitus using an indirect double immunofluorescence assay on prefixed cell samples. In order to exclude sensitization to heterologous insulin as a possible factor affecting the results, the patients were investigated at the day of clinical onset, before receiving insulin. An increased percentage of T cells (CD3+ cells) expressing class II antigens was seen in 19 out of 25 patients and class II expression was observed on cells within both the CD4+ and CD8+ T cell subsets. No correlation was found between the levels of class II expressing T cells and the individual degree of metabolic derangement or indicators of recent infection. Re-testing of 16 patients after one year on insulin treatment revealed a significant decrease of class II expressing T cell levels. Our data suggest that the increased levels of class II expressing T cells seen in IDDM of recent onset directly reflects immune reactions that are related to the disease process.

Adolescent↗
PubMed1988

Serum selenium is related to low-density lipoproteins in healthy children but not in children with diabetes.

The serum concentrations of selenium in 13 healthy children and 27 children with type 1 diabetes mellitus were evaluated in relation to serum lipoprotein and apolipoprotein concentrations. In healthy children a correlation was found between serum selenium and both serum cholesterol (r = 0.56; p less than 0.05) and serum triglycerides (r = 0.56; less than 0.05) and their low-density lipoprotein (LDL) + very low-density lipoprotein (VLDL) fractions (r = 0.60 and 0.56 respectively; p less than 0.05), but not their high-density lipoprotein fractions. Associations were also found between selenium and apolipoproteins, especially A II and C II (r = 0.57; p less than 0.05). In diabetic children serum selenium was significantly correlated with apolipoproteins A II and Apo C II, but not with any lipoprotein or lipid or any of their fractions. This study supports the hypothesis that serum selenium is an integral part of the defence system against degradation products associated with LDL and VLDL in young healthy humans. These associations were not found in diabetes, which might suggest that the defence system against lipid peroxidation is less effective in this disease.

Adolescent↗
PubMed1988

Impaired vascular reactivity during the first two years of diabetes mellitus after initial restoration.

Vascular reactivity was studied prospectively in 36 consecutive children (15 males, 21 females) below 15 years from the county of Uppsala with newly acquired type I diabetes mellitus (IDDM). Skin postocclusive hyperaemia was recorded with a transcutaneous oxygen electrode at 37 degrees C on admission before receiving insulin treatment and 1, 6, 12 and 24 months after diagnosis. Fifty-eight healthy children (25 males, 33 females), served as a reference group. The relations between vascular reactivity and age, sex and a number of biochemical variables that are often disturbed in IDDM were analyzed. On admission, the vascular reactivity was significantly lower in diabetic children than in controls (p less than 0.001). This reduction was normalized during the first month of treatment. After two years of diabetes, the vascular reactivity was again significantly lower in diabetic children than in the control group (p less than 0.001). There was no significant correlation between the vascular reactivity, the lag phase or baseline variables and any of the factors mentioned above at any time of investigation, except that serum magnesium was significantly correlated with vascular reactivity after six months of IDDM. It is suggested that the mechanism underlying an impairment of vascular reactivity on admission (reversible) is different from that of the late reduction, which might be a very early manifestation of the later structural diabetic microangiopathy.

Adolescent↗
PubMed1987

Skin reactive hyperemia recorded by a combined TcPO2 and laser Doppler sensor.

The tcPO2 electrode used at 37 degrees C monitors changes in cutaneous PO2 which at this temperature is mainly determined by the changes in blood flow. Laser Doppler velocimetry (LDV) measures the product of red cell number times their velocity. A comparison of these methods for the detection of skin reactive hyperemia has been made with a combined tcPO2 and laser Doppler sensor. The two parameters increased and decreased in parallel, the tcPO2 signal being delayed 10-20 s compared to the LDV signal. A significant correlation between the two signals was obtained (r = 0.73-0.93). In contrast, no significant correlation existed between the postocclusive peaks of the two signals recorded in 12 duplicate experiments. Comparing the peak amplitudes from the repeated recordings the tcPO2 signal showed a higher correlation coefficient (r = 0.91) and smaller intercept than the LDV signal (r = 0.74). Both methods can be used for non-invasive recordings of skin reactive hyperemia. The tcPO2 signal at 37 degrees C reflects changes in blood flow of the most superficial capillaries and reactive hyperemia can be monitored with high reproducibility. Only this signal can be used for calculation of skin blood flow. The LDV signal conveys information of blood flow changes mainly of deeper dermal vascular beds and reacts virtually instantaneously, but is less reproducible.

Blood Gas Monitoring, Transcutaneous↗
PubMed1987

Impaired vascular reactivity in newborn infants of smoking mothers.

A transcutaneous PO2 technique was used to study the influence of cigarette smoking during pregnancy on postocclusive reactive hyperaemia of the skin of newborn infants and their mothers. Forty-seven mothers and their infants were studied on two occasions (24-48 and 96-144 h) after birth. Twenty of the mothers were habitual smokers, 27 were non-smokers. All mothers were healthy and their pregnancies and deliveries were normal. The infants were all healthy throughout their first week of life. The mothers had more marked reactive hyperaemia than their newborn infants (p less than 0.001). Infants of smoking mothers had a significantly weaker postischaemic hyperaemic response 24-48 h after birth than infants of nonsmoking mothers (p less than 0.01). This difference had disappeared 96-144 h after birth. Smoking mothers also showed a significantly weaker hyperaemic response to ischaemia than the control mothers at the first investigation (p less than 0.05). This difference was smaller and not statistically significant at the second recording. A decreased capacity for postocclusive reactive hyperaemia might be particularly harmful in asphyctic infants, but it may also be detrimental for a normal postnatal circulatory adaptation.

Blood Gas Monitoring, Transcutaneous↗