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Biomedical subjects

H Olesen

Publications and source records attributed to H Olesen.

At least 19 recordsLinked to original sources
PubMed1992

Prediction of pseudophakic anterior chamber depth with the newer IOL calculation formulas.

Five methods for predicting pseudophakic anterior chamber depth (ACD) by five previously described intraocular lens power calculation formulas (Binkhorst II, Lepper and Trier, Holladay et al., Sanders-Retzlaff-Kraff (SRK/T), Olsen et al.) were evaluated in a series of 640 patients with a posterior chamber lens implant. Significant differences in formula performance were found in unusually short and long eyes. High errors were found in long eyes with the Lepper and Trier formula, the Holladay formula, and the SRK/T method. The highest accuracy was found with the Binkhorst formula and our previously described linear regression formula which expresses the pseudophakic ACD as a function of the average pseudophakic ACD for a given lens style, the preoperative ACD, and the axial length. The use of the preoperative ACD in combination with the axial length for the prediction of the pseudophakic ACD can therefore be expected to improve the accuracy of IOL power calculation.

Adolescent↗
PubMed1990

Prediction of postoperative intraocular lens chamber depth.

The postoperative intraocular lens (IOL) chamber depth was predicted using a multiple linear regression analysis of the postoperative chamber depth as a function of the corneal height, the preoperative chamber depth, and the axial length in 279 patients with a posterior chamber lens implant. Based on a linear regression formula incorporating these preoperatively defined parameters, the postoperative IOL chamber depth could be predicted with a correlation coefficient of 0.71 and an error of +/- 0.30 mm (SD). It is concluded that an individual prediction of the IOL chamber depth will improve the accuracy in IOL calculation.

Aged↗
PubMed1989

Human intrinsic factor. Its primary structure compared to the primary structure of rat intrinsic factor.

Human intrinsic factor was digested by trypsin and the resulting peptides purified by gelfiltration. Two peptides were sequenced to a total of 61 amino acid residues. Including the sequence for the N-terminal peptide and four cyanogen bromide peptides previously reported, we have now determined a total of 163 amino acid residues, that is a fraction of about 0.40 of the primary structure of human intrinsic factor. The 110 of the 163 residues known of human intrinsic factor are identical to the sequence of rat intrinsic factor.

Amino Acid Sequence↗
PubMed1989

Hemoglobinopathies in Danish families.

Based on cases referred for investigation, as well as a questionnaire sent to all medical and pediatric departments in Denmark, 48 cases of hemoglobinopathy in 15 families of Danish ancestry are reviewed. 18 Danes in six families have been identified as having beta-thalassemia, and remarkably one - a homozygote - has beta-thalassemia intermedia requiring treatment with iron-chelation therapy. A further 36 Danes in 9 families have a hemoglobin variant: five unstable hemoglobins (Volga, Niteroi, and three unidentified), one hereditary methemoglobinemia (M-Arhus), one polycythemia (Ty Gard) and 2 asymptomatic (Athens-Georgia and Hafnia). Although rare in Danish families, a hemoglobinopathy should be considered in families with an unexplained chronic hemolytic anemia, cyanosis or polycythemia.

Denmark↗
PubMed1988

Glycated hemoglobin as a measure of physiological stress.

The concentration of glycated hemoglobin (HbA1c) is an integrated expression of the blood glucose concentration level in the previous weeks. The levels of HbA1c were measured in 23 medical students who had to pass an examination within a few weeks. Twelve other students served as a control group. Four months later, the blood tests were repeated. In addition, serum cholesterol was measured. HbA1c levels were significantly higher in the exam group compared with the control group. The second test revealed a significant decrease in HbA1c in the exam group, while the values in the control group were stable. No differences in serum cholesterol were detected. It is concluded that HbA1c might be of value as a measure of physiological stress.

Adult↗
PubMed1987

Pulse oximetry versus transcutaneous pO2 in sick newborn infants.

A pulse oximeter (Ohmeda Biox 3700) and two transcutaneous systems (Radiometer TCM3) were applied simultaneously to 18 newborn infants with respiratory insufficiency. All infants had either an umbilical catheter placed in the mid thoracic aorta or a radial artery catheter. The average monitoring time was 2 hours. Arterial blood pO2, pCO2 and pH (Radiometer ABL300), arterial sO2, HbCO and metHb (Radiometer OSM3), erythrocyte 2,3 DPG concentration, and fetal hemoglobin fraction (alkali denaturation kinetic method) were measured. Using arterial sO2 and pO2 as reference, the analytical bias of pulse oximetry (-0.5 +/- 1.0%, mean +/- 1 SD) corresponded in magnitude, when converted to pO2, to that of transcutaneous - pO2 (0.6 +/- 1.4 kPa for combined O2-CO2 electrode and -0.1 +/- 2.3 kPa for single O2 electrode). Transcutaneous pCO2 showed the smallest bias (0.3 +/- 0.3 kPa). Both pulse oximetry and transcutaneous pO2 electrodes were good as trend monitors detecting rapid changes in the infants' oxygenation status. The pulse oximeter offers certain advantages in not requiring calibration or heating. The variations in the levels of fetal hemoglobin fraction (44 to 97%), pH (7.27 to 7.49), pCO2 (3.3 to 6.8 kPa) and 2,3 diphosphoglycerate concentration (1.6 to 5.9 mmol/l) between the infants studied, resulted in a variable pO2-sO2 relation (p50 2.5 to 3.5 kPa). This presents difficulties in interpreting sO2 values in sick newborn infants, and we therefore recommend caution in using a pulse oximeter to apply strict limits for avoiding hypoxia and hyperoxia in this population.

Blood Gas Monitoring, Transcutaneous↗
PubMed1984

Reference intervals for urinary glucose in pregnancy.

Reference interval upper limits for glucose in urine from non-fasting pregnant women, estimated by a glucose dehydrogenase method are higher than for non-pregnant women (1.4 mmol/l) and increase with gestational age: week 10-20, 2.0 mmol/l (n = 158); week 21-30, 2.3 mmol/l (n = 124) and week 31-42, 2.7 mmol/l (n = 245). The reagent strip Tes-Tape correctly identified glucosuria above a clinical decision limit of 7 mmol/l and reacted in two-thirds of urine samples with from upper reference interval to 8 mmol/l of glucose. The reagent strip Uristix in no case gave a positive reaction.

Adolescent↗
PubMed1981

Purification and characterization of rabbit haptocorrin.

Rabbit haptocorrin (R-binder) has been purified from serum by affinity chromatography on cobalamin-Sepharose and Blue Sepharose. It proved to be a protein with a relative molecular mass of 60 000 and an amino acid content very similar to that of other haptocorrins (Nexø, E. and Olesen, H. (1981) in B12 (Dolphin, D., ed.), Wiley Interscience, New York/London, in the press). The pH optimum (pH 6-9) for binding of cyanocobalamin and the affinity to dicyanocobinamide were like those of human and hog haptocorrins. In spectral studies, the extinction coefficient of cyanocobalamin at 363 nm (gamma 1-band) increased by about 16% on binding to rabbit haptocorrin. Binding of azidocobalamin gave spectra changes similar to those for binding to rabbit transcobalamin.

Amino Acids↗
PubMed1981

Volume of blood removed for analytical purposes during hospitalization of low-birthweight infants.

Iatrogenic hazards may be induced by blood sampling in very-low-birthweight neonates. We report the number and types of analyses performed on 20 neonates with a birthweight below 1500 g during their first four weeks of hospitalization. Blood was sampled one to 13 times per infant per day on 382 of the 435 total days of hospitalization. The average blood loss was 7 to 51 mL per kilogram of body weight per four weeks--that is, from 5 to 45% of the calculated total blood volume. Of the blood removed, about 25% was in excess of the need for analytical procedures. Of the analyses, 40% were for acid-base, sodium, and potassium analyses--analyses for which transcutaneous methodology has been or is being developed. We conclude that because of the risks for low-birthweight neonates, procedures for blood sampling and analysis should periodically be reviewed, so as to minimize the number of samplings and the amount of blood removed.

Blood Chemical Analysis↗