Biomedical subjects

U Ewald

Publications and source records attributed to U Ewald.

At least 73 records · Page 4Linked to original sources

PubMed1986

Arachidonic-acid-induced platelet aggregation is increased in male but not in female smokers.

Arachidonic-acid-induced platelet aggregation was studied in 40 healthy drug-free subjects aged 18-43 years. Aggregation was elicited by lower concentrations of arachidonic acid in smoking men (n = 10) than in non-smoking men (n = 10)(p less than 0.05). No significant difference was found between smoking and nonsmoking females. Adenosine-diphosphate-induced platelet aggregation was not increased in smokers. There was no difference between smokers and non-smokers with respect to mean platelet volume and count within each sex. Females and males differed regarding platelet count in whole blood and platelet sensitivity to arachidonic acid; both differences were secondary to the difference in hematocrit. The parallelism between an increased tendency to aggregation after arachidonic acid stimulation and an increased rate of myocardial infarction in male smokers, and the absence of both these phenomena in female smokers, might be of pathophysiological significance.

Adolescent↗

PubMed1986

Maternal smoking reduces prostacyclin formation in human umbilical arteries. A study on strictly selected pregnancies.

Production of prostacyclin (PGI2)-like activity in umbilical arteries in vitro was evaluated in 38 selected newborn infants. Nineteen of the mothers of these infants were habitual smokers and the remaining 19 were non-smokers. To rule out the possibility of disturbing effects of drugs or other factors, the newborn infants and their mothers fulfilled strict criteria regarding normality and control of drug intake. The infants of habitual smokers (greater than 5 cigarettes/day) (n=19) were compared with a control group (n = 19) with non-smoking mothers. Smokers' babies had lower birth weights than the controls (3,500 +/- 440 vs 3,900 +/- 420 g, p less than 0.001). Production of PGI2-like activity was estimated by a bioassay technique. Umbilical arteries of smokers' infants produced significantly less PGI2-like activity (139 +/- 78 ng/g arterial tissue) than those of the controls (201 +/- 87 ng/g) (p less than 0.05). As expected, the two groups differed highly significantly regarding serum levels of markers for exposure to cigarette smoke, but these levels did not correlate to formation of PGI2. Decreased production of PGI2-like activity in umbilical vessels might have an impact on nutritive blood flow and oxygen transport, especially in situations of asphyxia.

Adenosine Diphosphate↗

PubMed1985

High frequency of Coxsackie-B-virus-specific IgM in children developing type I diabetes during a period of high diabetes morbidity.

Twenty-four consecutive children with newly diagnosed insulin-dependent (type I) diabetes mellitus (IDDM) were investigated for a history of infectious disease. Thirteen of the 24 (54%) patients reported symptoms of acute infection within two months before diabetes was diagnosed. The mean age was 8.5 years and 15 (63%) of the patients were girls. No clear seasonal variation in onset was seen. Coxsackie B (CB)-virus-specific IgM responses were detected by reverse radioimmunoassay (RIA) in 16 of the 24 (67%) patients on the day of diagnosis of IDDM. The highest titre was usually recorded at that time, but with some the highest titre was found with a second serum obtained three to seven weeks after diagnosis. Thereafter the titres declined, and after six months IgM was detected only in a few patients. Thirteen patients displayed monotypic IgM responses, whereas three patients showed ditypic responses. Among the former, IgM was recorded against Coxsackie B4 (CB4) in four, B5 (CB5) in three, B1 (CB1) in two, B2 (CB2) in two, and B3 (CB3) in two patients. The ditypic responses were against CB2 and CB3, CB3 and CB4, and CB5. No CB-virus-specific IgM was detected in sera, found during the same period, from age-matched nondiabetic children without evidence of infection. In neutralisation (NT) tests, antibodies to the homotypic virus were found in 12 of the 16 diabetic patients showing CB-virus-specific at the time of diagnosis. A significant rise in NT titre was demonstrated in three of these patients. No significant clinical difference was noted between IgM positive and IgM negative patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Child↗

PubMed1985

Aggregation of and thromboxane B2 synthesis in platelets from newborn infants of smoking and non-smoking mothers.

Cord blood platelet aggregation and thromboxane B2 (TxB2) synthesis were investigated in 20 healthy infants of drug-free healthy mothers with an uncomplicated pregnancy ending at term in a normal vaginal delivery. Eight of the mothers were habitual smokers and the remaining 12 were non-smokers. The platelet count was slightly lower in infants of smoking mothers than in the control infants. There were no differences between the two groups in the qualitative or quantitative aggregation responses (maximal change in optical density) to stimulation by 0.55, 1.1, 3.3 and 6.6 microM adenosine diphosphate, 0.5 and 1.0 mM arachidonic acid (AA) or collagen 1.0 and 5.5 mg/l. Nor was there any difference between the groups in regard to TxB2 synthesis after stimulation by these substances. The amount of TxB2 synthesized merely reflected the occurrence of reversible or irreversible platelet aggregation. Stimulation of platelets by AA induced by far the highest synthesis of TxB2. The generally decreased aggregability of platelets of newborn infants, compared with that in adults, was confirmed in this study. No effect of maternal smoking during pregnancy on the prostaglandin-dependent pathway of aggregation of cord blood platelets was demonstrated.

Adult↗

PubMed1985

Detection of exercise-induced lactic acidosis using transcutaneous carbon dioxide.

Transcutaneous PCO2 (PtcCO2) measurements were used to monitor changes in systemic lactate levels during exercise. PtcCO2 increased in all 17 male volunteers, and this increase was significantly correlated with increases in measured plasma lactate concentration. In six volunteers, the PtcCO2 increase was greatest during the last minutes of work, indicating rapid lactic acid elimination from the muscles. In these six subjects, the rate of this increase also correlated significantly with the lactate increase. This technique is potentially of interest for detecting fatigue in athletes and for monitoring lactoacidosis as an indicator of circulatory impairment in shock patients.

Acidosis↗

PubMed1985

Reduced serum proteins in diabetic children on a twice-daily insulin schedule.

The concentrations of selected proteins of transport and nutrition were investigated in 27 diabetic children and 13 healthy controls by an immunodiffusion technique. The diabetic children had significantly lower mean pre-albumin (p less than 0.001), albumin (p less than 0.01) and orosomucoid levels (p less than 0.05) than the healthy controls. No correlation was observed between age or sex and the blood concentrations of the specific proteins analyzed in this series. Haptoglobin and hemopexin showed positive correlations with serum triglycerides (both p less than 0.01) and slight positive correlations with some of the variables of carbohydrate control. The reduced levels of prealbumin and albumin were not correlated to diabetic control as measured by HbA1, fasting plasma glucose or urinary glucose excretion. The non-physiological distribution site and the abnormal temporal pattern of insulin offered to diabetic children might be the reason for the protein abnormalities found in this study. This is seemingly the first time reduced serum levels of proteins have been reported in diabetic children.

Adolescent↗

PubMed1985

An incidence peak of juvenile diabetes. Relation to Coxsackie B virus immune response.

All new cases of insulin dependent diabetes mellitus (IDDM) in children below 15 years of age were recorded prospectively during a 21-year period 1964-1984 in a defined uptake area with a relatively constant child population. The total number of children recorded was 222-111 boys and 111 girls. The number of new cases varied between 4 cases in 1968 and 20 in 1984; in 1983 seventeen new cases were recorded. Specific IgM antibodies against Coxsackie B virus (CBV), types 1-5 were measured by a reverse radioimmunoassay (RIA) technique in 24 consecutive patients collected during the period March 1982-January 1984, some of whom represented the recent period of a very high incidence of diabetes. Sixteen patients (67%) exhibited CBV IgM responses, strongly suggesting a current or recent CBV infection. The titres declined during the first few months of diabetes and seemed to be absent after the first half-year period. Among age-matched non-diabetic children scheduled for elective procedures during the same period, no cases with CBV-IgM antibodies were detected. Only three of the 16 IgM-RIA-positive patients showed a significant rise in the neutralising antibody titre against the same Coxsackie B type. It is concluded that CBV may play a pathogenetic role in induction of IDDM, and possibly more frequently so during periods with a high incidence of diabetes, at least in children below 15 years of age.

Adolescent↗

PubMed1985

Dietary intake in Swedish diabetic children.

The energy and nutrient intakes by 14 children with type I diabetes and 13 healthy peers were investigated by the 24-h recall method and the results were compared with current recommendations for the general population and with the guidelines for the dietary management of diabetes mellitus. The diabetic children showed not only good compliance with the recommendations but also a better intake in practically all respects than their healthy counterparts. The total energy intake by the diabetic children was in good agreement with the recommendations, while that of the controls was slightly lower. The protein energy per cent in the diet of the diabetic children was 18%, compared with 14% in the controls. Forty percent of the energy in the diet of the diabetic children was derived from fats, 36% in the controls. With the exception of carbohydrates, ascorbic acid and iron, the diet of the diabetic children had a higher nutrient density than that of the control children and the reverse was true for carbohydrates only. However, because of the generally higher energy intake displayed by the diabetic children, even the intake of these nutrients was at least as good in the diabetic children as in the controls. Eighty-six percent of the diabetic children but only 46% of the control children stated that the day for which intake data were given was a representative day.

Adolescent↗

PubMed1985

Dietary intake, trace elements and serum protein status in young diabetics.

Dietary intake of energy and nutrients and its relation to trace element and protein status, as observed in 27 diabetic children and 13 healthy controls are discussed. The diabetic children had consistently higher intakes than the healthy controls in nearly all respects, except for carbohydrate and ascorbic acid. In spite of this, the diabetic children had a significantly lower mean serum magnesium than the healthy controls. It is suggested that hypomagnesemia in diabetic children may be the result of increased urinary loss or diversion of magnesium from normal metabolic pathways in this disease. This review also revealed a significantly higher mean serum selenium level in the diabetic children than in the healthy controls. However, no significant correlation was observed between serum selenium concentrations and protein intake, suggesting that a factor other than protein intake underlay the elevated levels of serum selenium. The diabetic children as a group had significantly lower levels of selected serum proteins than the controls, in spite of a significantly higher intake of protein by the diabetic group. It is suggested that both reduced serum proteins and elevated levels of serum selenium in the diabetic children are an expression of altered metabolism in combination with the effects of current modes of insulin treatment in this disease.

Adolescent↗

PubMed1985

Platelet aggregation during the first year of diabetes in childhood.

Platelet aggregability in 24 newly diagnosed diabetic children was investigated on five occasions from onset of the disease until one year after diagnosis. Twenty healthy children of similar age and sex served as controls. The magnitude of the platelet shape change after adenosine diphosphate (ADP) stimulation was decreased in diabetic children on admission (p less than 0.05) in comparison with controls, but normalized during the year of the study. Maximal aggregation and initial rate of aggregation after ADP stimulation did not change significantly during the study year, and did not differ from those in controls. Aggregation by low dose collagen (0.5 and 1.0 mg/l) increased significantly (maximal aggregation, p less than 0.01; aggregation velocity, p less than 0.001) in the diabetics during the first year after admission from seemingly normal to clearly supranormal. Aggregation induced by high-dose collagen (5.5 mg/l) remained unchanged during the observation period and did not differ from that in the control group. No correlations were found between the indicators of platelet aggregation and those of carbohydrate control at any time after diagnosis. Platelet dysfunction is thus present already during the first year of diabetes. The different time course of the ADP-induced platelet shape change and collagen-induced aggregation imply that the mechanisms underlying the abnormalities of these two platelet functions differ.

Adenosine Diphosphate↗

PubMed1985

Vascular reactivity during the first year of diabetes in children.

Functional vascular response to hypoxia was studied in 24 children followed up prospectively for one year after diagnosis of type 1 diabetes mellitus. Postocclusive reactive hyperaemia was detected non-invasively in the skin using a transcutaneous PO2 method at 37 degrees C. Repeated experiments under standardized conditions were performed before institution of insulin treatment and 3, 7, 21, 30, 180 and 360 days after diagnosis. Impaired vascular reactivity was noted at the first experiment as compared with control children and slight but significant improvement was then noted up to the experiment at 180 days (p less than 0.01). At 30 and 180 days no significant difference between diabetic and control children was found. A small decrease in mean postocclusive reactive hyperaemia was observed at the experiment performed after 360 days. Fast normalization of urine glucose excretion, blood glucose and haemoglobin A1 occurred during the first three weeks of treatment but these variables showed no significant correlation to vascular reactivity, either at diagnosis or later. Impaired vascular reactivity can thus be diagnosed even before the institution of insulin treatment and improves during the first months of treatment, reaching the range of controls. Other factors than indicators of carbohydrate control have to be studied in the search for explanations of the abnormal vascular function in newly diagnosed diabetic children.

Adolescent↗

PubMed1985

Reduced vascular reactivity in diabetic children and its relation to diabetic control.

The vascular reactivity in response to ischaemia was studied by a non-invasive method of measuring transcutaneous oxygen tension used at 37 degrees C, in 28 children with type I diabetes mellitus. Postischaemic hyperaemia was significantly reduced in the diabetic children compared with 34 healthy children. The degree of reduction in vascular reactivity correlated to both short-term and long-term diabetic control. Among tested variables, urinary glucose excretion during the night preceding the test showed the highest coefficient of correlation to the peak of the postocclusive reactive hyperaemia (r = -0.59, p less than 0.01). This peak was only weakly correlated to triglycerides and glycosylated haemoglobins and showed no significant correlation to fasting plasma glucose or to the duration of the disease. It was weakly correlated to the total daily insulin dosage but not to the dosage of insulin/kg body weight. Multiple linear regression analysis revealed that urinary glucose excretion, plasma glucose, haemoglobin A1, serum triglyceride and serum cholesterol, duration of diabetes, and insulin dosage per kg body weight together explained 54% of the variation in vascular reactivity. The reduced vascular reactivity found in diabetic children could not be explained by the usual parameters of carbohydrate control alone. This new non-invasive method is able to reveal a reduction in vascular function in diabetic children and should therefore be of value in attempts to find the causes of vascular dysfunction in diabetics.

Adolescent↗

PubMed1985

Arachidonic acid-induced aggregation of platelets from human cord blood compared with platelets from adults.

Using a double-sample technique, platelet aggregation induced by arachidonic acid (AA) was studied in cord blood samples from 29 newborns and 20 adults, all healthy and drug-free. Of the platelets from adults (10 males, 10 females), all aggregated after 1.0 mM AA. After 0.5 mM AA, all platelets aggregated except those from 4 males which did not respond at all. The great majority of cord blood samples aggregated similarly to samples from adults. Platelets from all 15 newborn females and 11 of 14 newborn males aggregated irreversibly after 1.0 mM AA, while those from 3 of the 14 male newborns showed a reversible aggregation. All 11 newborn samples aggregated irreversibly after 0.5 mM AA. These results prove that the cyclo-oxygenase pathway for platelet aggregation operates satisfactorily in newborn infants. The double-sample technique is of value for cord blood samples. Late cord blood samples showed more marked aggregation than samples taken earlier.

Adult↗

PubMed1985

Anaerobic skin metabolism in healthy men estimated with transcutaneous PCO2 electrode.

It is shown how the anaerobic energy production of the skin may be calculated from a transcutaneous PCO2 curve obtained at 37 degrees C during arterial occlusion. Thirty healthy volunteers were studied three times. The inter-individual differences in estimated ATP production were highly significant, but the intra-individual ones were not. The grand mean of the triplicate experiments of all the 30 subjects was an ATP production rate of 0.33 mmol X l-1 X min-1. Assuming no initial metabolic acidosis or alkalosis, the estimated mean extracellular fluid pH was 7.33 before and 7.26 after 4 min of stasis.

Adenosine Triphosphate↗

PubMed1984

Increased high density lipoproteins in diabetic children.

Serum lipoprotein lipid and apolipoprotein concentrations were determined in 27 diabetic children (5-18 years old) and 13 matched healthy controls. The serum cholesterol concentrations in the diabetics were slightly higher than in the controls (P less than 0.05) due to a significantly higher level of the high density lipoprotein cholesterol (P less than 0.01). Also the serum concentration of apolipoprotein A-I, the major protein constituent of the high density lipoprotein fraction, was higher in the diabetic children (P = 0.05). There were no significant differences between the groups with regard to the serum triglyceride concentrations or the apolipoprotein C-II and C-III concentrations. Neither the lipoprotein lipid nor the apolipoprotein levels were significantly correlated with variables related to the degree of regulation of the diabetic disease. No obvious explanation, based on the present data, can be given for the increased high density lipoprotein cholesterol concentrations in insulin-treated diabetics in comparison with the healthy children. It is possible, however, that the increased high density lipoprotein cholesterol concentration may be caused by an increased level of insulin in the circulation of insulin-treated diabetic children.

Adolescent↗

PubMed1984

Evaluation of the transcutaneous oxygen method used at 37 degrees C for measurement of reactive hyperaemia in the skin.

The transcutaneous oxygen electrode used at an electrode temperature of 35-37 degrees C measures changes in PO2 at the skin surface that are mainly determined by changes in skin blood flow. Simultaneously, information about tissue PO2 in a defined skin area can be obtained by calculation. The reproducibility of this new application of the transcutaneous PO2 technique and factors influencing the recordings were analysed. Reactive hyperaemia was best recorded at 37 degrees C, where the coefficient of variation (CV) was 14% and the correlation coefficient was 0.90 between duplicate measurements within 15 min (n = 57). The day-to-day variation was greater (CV 19-28%). No significant spatial differences in reactive hyperaemia were noted when the distance between the electrodes was no more than 3 cm on the same forearm. A slightly lower reactive hyperaemia was noted when the arm with the electrode was elevated above the level of the heart, as compared with a lower position. Age and sex had significant influence, children (n = 34) exhibiting a greater postocclusive peak tcPO2 response than adults (n = 67). In adults, females (n = 30) showed significantly higher peak tcPO2 values during reactive hyperaemia than males. This method is a new application of the tcPO2 technique and can be used as a noninvasive tool for simultaneous blood flow and tissue PO2 studies in microcirculatory research.

Adolescent↗

PubMed1984

Elevated serum selenium in diabetic children.

Twenty-seven diabetic children, 16 girls and 11 boys, 5-18 years of age, with a duration of the disease ranging from 2-15 years, comprised the study group. Thirteen children with a similar age and sex distribution, living in the same area served as healthy controls. All 40 children had a normal growth pattern. The mean serum selenium concentration in the diabetic children, determined by neutron activation analysis, was 7.4 +/- 0.8 micrograms/100 ml (mean +/- SD) and in the healthy controls 6.5 +/- 0.8 micrograms/100 ml. The difference between the two groups was statistically highly significant (p less than 0.01). Boys and girls in both groups had nearly identical mean serum selenium levels and no correlation was observed between the selenium concentrations and either the age, weight or height of the children or the indicators of diabetic control. The selenium status in diabetic children has not been reported previously. The possibility of elevated serum selenium in diabetic children in response to altered lipid metabolism is discussed.

Adolescent↗

PubMed1984

Reevaluation of home urine glucose measurements in diabetic children. A computerized study of short-term control variables in the prediction of long-term diabetic control.

The relationship between ClinitestR home control results and HbAI and triglycerides was analyzed by a computerized optimizing procedure. The morning urine glucose excretions in the 10 preceding weeks were strongly correlated with HbAI as were the evening excretions, while the afternoon records showed only weak correlations with HbAI. Maximal correlations between home glucose records and HbAI were achieved when mornings and evenings were added, with higher weights given to the mornings. The practical consequences are that home urine test results in the mornings and evenings are of most value when adding home scores for assessment of long-term diabetic control, whereas afternoon records should be ignored for this purpose. Serum triglycerides were correlated with glucose excretion during the week of triglyceride determination, but not with glucose excretion measured in the preceding weeks. Serum cholesterol did not reflect diabetic control at all.

Adolescent↗