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Biomedical subjects

O Blaabjerg

Publications and source records attributed to O Blaabjerg.

50 records · Page 3Linked to original sources
PubMed1989

Effect of folic acid supplementation on small-for-gestational-age infants born at term.

The effect of 250 micrograms folic acid (FA)/day or placebo given to 21 small-for-gestational-age infants born at term was studied during the first 3 months of life. The design of the study was double blind with random allocation. No randomization was performed in respect of breast-feeding or formula-feeding with a folate content of 60-70 micrograms/l. No significant differences were observed in haemoglobin concentration, haematocrit, weight and length between FA-supplemented and non-supplemented infants. A negative correlation was demonstrated between gestational age and erythrocyte folate (E-folate) concentration at 1 week. E-folate content was higher when no supplement was given in breast-fed than in formula-fed infants.

Bottle Feeding↗
PubMed1989

Analytical goals for the estimation of non-Gaussian reference intervals.

Goals for analytical quality are postulated for the situation in which a number of laboratories will share common reference intervals for some quantities for which the population is homogeneous. These goals are evaluated on the assumption that the acceptable combined analytical bias and imprecision should not allow the percentage of the population outside either upper or lower reference limits to exceed the interval 1.3 to 4.4%. The goals are evaluated for log-Gaussian biological distributions, and for distributions which can be transformed into log-Gaussian by addition of a constant value to all elements. Further analytical goals for non-parametric distributions are discussed. For log-Gaussian distributions the maximum allowable bias and imprecision are dependent on the ratio of the upper and lower reference limits. When this ratio is c. 1.25, the bias alone must be less than 1.5% or the coefficient of variation alone less than 3.5%. For a ratio of 10, these values may be as high as 15% and 34%, respectively.

Chemistry, Clinical↗
PubMed1988

Serum lactate dehydrogenase isoenzyme 1 as a marker of testicular germ cell tumor.

Serum lactate dehydrogenase isoenzyme 1 activity was determined repeatedly in 21 men with testicular germ cell tumors in connection with orchiectomy and in 25 without neoplasia who underwent exploration of the testis. The highest level in the men without malignancy was 109 units per 1. and a higher pre-orchiectomy level was found in 15 of the tumor patients: 7 of 11 with seminoma and 8 of 10 with nonseminomatous tumors. In the patients with stage 3 disease serum lactate dehydrogenase isoenzyme 1 was increased more often and the activity was higher than in the stage 1 and 2 cancer patients. Within 1 month after orchiectomy the initially increased level decreased to less than 109 units per 1. in 8 of 10 patients with a stage 1 tumor and it remained higher in 5 with stage 2 or 3 disease. Serum lactate dehydrogenase isoenzyme 1 seems to be a useful marker of testicular germ cell tumor.

Adult↗
PubMed1988

Analytical goals for the acceptance of common reference intervals for laboratories throughout a geographical area.

Analytical goals required for the successful transfer of reference intervals between laboratories within a specified limited geographical area, with a population homogeneous for the quantities, are presented. Diagrams are shown which allow the investigation of the influence of analytical imprecision and bias, both separately and in combination, on the percentage of the population outside each reference limit. Figures to evaluate the effect of population sample size on the size of confidence interval around each reference limit are combined with the diagrams for analytical imprecision and bias. The maximum acceptable percentage of the population outside the limit for the 0.90 confidence interval of each of the means +/- 1.96 s reference limits is 4.6% for a population sample size of 120. Based on this, the maximum acceptable imprecision, with no bias, is 0.6 of the total biological standard deviation (sB) and the maximum acceptable bias, with no imprecision, is 0.25 sB.

Chemistry Techniques, Analytical↗
PubMed1987

Atrial natriuretic peptide in relation to physical exercise.

The effect of physical exercise on atrial natriuretic peptide (ANP) was studied in 10 healthy young volunteers. The subjects were exercised on a bicycle ergometry until exhaustion. Blood samples were drawn at rest, at maximal load and in the following resting period. ANP concentrations were measured by radio-immunoassay. The level of ANP rose from 6.7 +/- 0.5 at rest to 33.2 +/- 7.0 pmol/l (mean +/- SEM) (p less than 0.05) at maximal load and returned to normal after 45 min. It was not possible to demonstrate a correlation between a change in ANP concentration and changes in pulse rate, blood pressure, maximal physical load, volume of urine, the amount of urine sodium, urine potassium or urine creatinine during the exercise load.

Adult↗
PubMed1986

Lipoprotein electrophoresis in recessive X-linked ichthyosis.

Recessive X-linked ichthyosis (RXLI) is consistently associated with steroid sulphatase deficiency, and a definite diagnosis can be made by measurement of the activity of this enzyme, e.g. in cultured skin fibroblasts and leucocytes. Demonstrating an increased electrophoretic mobility of plasma low-density lipoprotein in RXLI patients has been proposed as a simpler method for the diagnosis of this condition. Our findings in 7 RXLI patients and 7 normal controls confirmed that a discrimination between patients and controls can be obtained by routine lipoprotein electrophoresis. However, due to variation in the results of repetitive performances further studies are needed to evaluate the overall reliability of this diagnostic approach.

Blood Protein Electrophoresis↗
PubMed1984

The impact of quality control materials on the performance of an internal quality control system: 1. General considerations.

Quality assurance in clinical chemistry is based on statistical control procedures designed to maintain a certain level of quality. Decisions about acceptance or rejection of analytical series are made primarily from measurements of quality control materials. Such materials are most often of non-human origin; this may lead to false decisions due to non-identity of patient samples and quality control material. We have investigated the significance of non-identity between patient and control materials by running two separate quality control systems in parallel. A regular system used for acceptance or rejection of series, and a parallel system used for registration of the actual quality of the analytical routine work. The results from the latter system have not been available for the operator handling the control system used in routine work. Our study has confirmed the validity of an internal quality control system to achieve a certain level of analytical stability as expressed by the short-term and long-term precision. However, because ideal control materials are not always available, additional procedures to control accuracy, specificity, and detectability may be necessary. The usefulness of such procedures to properly handle error signals from quality control systems has been demonstrated.

Chemistry, Clinical↗
PubMed1984

The impact of quality control materials on the performance of an internal quality control system: 2. Experiences from S-calcium analysis.

In this subproject the analysis of S-calcium was used for evaluation of the specified system of internal quality control. Decisions on acceptance or rejection of series were based on a non-human pool with a calcium concentration near the upper reference limit. In the parallel system, specimens from patients and healthy individuals were used together with other non-human pools to disclose changes in accuracy. The results were examined for false rejections and false acceptances. In all the rejections based on a mean rule with 9 controls and a pfr of 0.01, the parallel system supported the decisions. On 18 occasions the series were rejected based on a range rule with a pfr of 0.05. Ten of the rejections were confirmed by the parallel system, and the remaining eight times of the 165 series were close to the expected five per cent of false rejections. The matrix effect estimated from the human and non-human serum pools was less than 15 per cent of the total variation. This supported the convenient use of non-human control materials in the analysis of S-calcium. The total variation, CVt, was estimated to be in the range of 0.027-0.030. The median of the patient results could be a valuable tool in quality control, whereas the mean of patient results within the reference limits is of no value. In conclusion, the investigation confirmed the validity of a system for internal control of a specified quality.

Analysis of Variance↗
PubMed1984

The impact of quality control materials on the performance of an internal quality control system: 3. Experiences from S-triiodothyronine analysis.

In this subproject a method for S-triiodothyronine was used for evaluation of the specified system of internal quality control. Decisions on acceptance and rejection of series were based on results from a human pool with triiodothyronine concentration at the upper reference limit. In the parallel system specimens from patients and from healthy individuals were used in combination with artificial materials so that changes in accuracy, specificity, and detectability could be disclosed. The results were examined for false rejections and false acceptances. For all the seven rejections in 117 series due to a mean rule of 8 controls with a pfr of 0.01, the parallel system supported the decisions. In eight occasions the series were rejected due to a range rule with a pfr of 0.05; one rejection was confirmed by the parallel system and the remaining seven times out of the 117 series were close to the expected five percent of false rejections. A small systematic change in standardization of about eight percent was too small to be recognized by the quality control system. The specificity was not changed during the investigation period; all of the systematic changes were caused by variations in the standard materials. In conclusion the investigation confirmed the validity of the specified system of internal quality control.

False Negative Reactions↗
PubMed1981

Variability of plasma proteins according to molecular size. Long-term and short-term intra-individual variation.

The intra-individual variations in serum concentrations of alpha 1-antitrypsin, albumin and alpha 2-macroglobulin were determined using high precision analytical methods. The long-term (3 months) variations were 8.2% for alpha 1-antitrypsin and 2.9% for alpha 2-macroglobulin in five males and five females. The coefficients of variation for albumin were 1.5 and 3.4% for males and females, respectively. In males the long-term variations of albumin and alpha 2-macroglobulin were highly correlated. The short-term (2 days) intra-individual variations in six males were 2.5, 3.8 and 3.4% for alpha 1-antitrypsin, albumin and alpha 2-macroglobulin respectively (coefficients of variation). A diurnal variation was found for albumin with maximal concentrations at 18.00 hours. At 6.00 and 10.00 hours the fractional concentrations of alpha 1-antitrypsin and albumin were lower than for alpha 2-macroglobulin. The variations of the three proteins were positively correlated.

Adult↗
PubMed1980

Long-term variability in serum thyroglobulin and thyroid related hormones in healthy subjects.

From 5 young males and 5 young females blood was drawn under highly standardized conditions at 6 to 10 occasions during 4 months. The serum constituents thyroglobulin, thyroxine, triiodothyronine, T3-uptake test, TBG and TSH were determined, and four indices were calculated. The biological intra-individual coefficients of variation were below 0.14 for thyroglobulin, and the inter-individual coefficients for variation ranged from zero for T3-uptake test to 0.35 for thyroglobulin. All results were within the generally accepted reference ranges for normals. Within these ranges the calculations of indices for free thyroxine and triidothyronine according to T3-uptake test and TBG, did not significantly reduce the coefficients of variation for these serum constituents. Thyroglobulin concentrations did not correlate to any of the measured or calculated constituents. The knowledge of these intra- and inter-individual variations of serum thyroglobulin in healthy persons is of importance for the interpretation of variations found in patients.

Adult↗
PubMed1979

Effect of aggregates on albumin standardization.

In order to investigate the consequences of presence of aggregates in human albumin standards, pools of monomer, dimer and polymer albumin were prepared and quantitated by three total-protein methods (biuret, Folin-Lowry and spectrophotometry at 279 nm) and by four different albumin methods (dye-binding by bromcresol green, electroimmunoassay, radial immunodiffusion and automated immunoprecipitation). Biuret was chosen as the reference method and the monomer was used as the standard in all methods. Both the total-protein and albumin methods gave values for aggregated albumin different from the biuret values. The maximal bias occurred in radial immunodiffusion where quantitation of the dimer and polymer pools gave only 67% and 48% of the biuret values, respectively. In five commercial albumin preparations investigated, the content of di- and polymer varied from 3 to 34%. Uncritical use of albumin preparations in standardization may thus introduce bias in the measurements.

Albumins↗
PubMed1977

Repair in arterial tissue. The role of endothelium in the permeability of a healing intimal surface. Vital staining with Evans blue and silver-staining of the aortic intima after a single dilatation trauma.

The role of the endothelium as a factor determining the permeability of a healing aortic intima after a severe mechanical lesion in the rabbit was studied by vital staining with Evans blue, by surface light microscopy after silver-staining, fluorescence microscopy and by other methods. Endothelium to develop from pre-existing endothelium in the mouths of intercostal arteries and at the borders of the lesion, remained unstained by vital staining, whereas denuded surfaces as well as pseudo-endothelium, probably derived from smooth muscle cells in the neointima, were intensely coloured. There was a general tendency towards a decreasing permeability of the aortic wall throughout an experimental period of 6 months. The determinant factor in the decreasing permeability was the presence of genuine endothelium, but changes in the endothelium, probably in the form of differentiation of intercellular junctions and changes in the connective tissue in the deeper layers, seemed to be additional factors which influenced the permeability.

Animals↗