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Biomedical subjects

N Fogh-Andersen

Publications and source records attributed to N Fogh-Andersen.

119 records · Page 7Linked to original sources

Lactate dehydrogenase isoenzyme 1 in the diagnosis of myocardial infarction.

A new immunochemical method for the measurement of lactate dehydrogenase isoenzyme 1 (LDH-1) was used on 113 consecutively admitted patients with suspected myocardial infarction. Using WHO's criteria and our routine program 49 were classified as having myocardial infarction and 64 as having no myocardial infarction. LDH-1 was better than total lactate dehydrogenase is discriminating between patients with and without myocardial infarction (p less than 0.02), and the efficiency (the number of correct classifications divided by the total number of analyses) on day 2-3 equalled that from the literature for CK-MB on day 1. Total lactate dehydrogenase and LDH-1 are supplemental to creatine kinase (CK) and CK-MB, while aspartate aminotransferase may be omitted in the diagnosis of myocardial infarction. Determination of the ratio of LDH-l to total lactate dehydrogenase offered to no advantage.

Aged↗

Effect on serum calcium of a alpha-hydroxy-vitamin D3 supplementation in infants of low birth weight, infants with perinatal asphyxia, and infants of diabetic mothers.

Thirty infants of low birth weight, 35 infants with perinatal asphyxia, and 16 infants of diabetic mothers were investigated for early neonatal hypocalcaemia. The infants were randomized into a group prophylactically given 1 alpha-hydroxy-vitamin D3, 0.05 or 0.10 micrograms/kg i.v. on the first 3 days of life, and an untreated control group. In infants of low birth weight and infants of diabetic mothers there were no differences in serum ion-Ca concentrations on days 2, 3, 5, and 7 between the treated and untreated groups. In infants with perinatal asphyxia, however, serum ion-Ca concentrations on days 5 and 7 were significantly higher in the treated than in the untreated group, while on days 2 and 3 the differences were not statistically significant. The hypocalcaemia in asphyctic infants was not correlated to bicarbonate treatment, but infants with severe signs of asphyxia had lower serum ion-Ca concentrations than infants with only mild or no signs. Hypocalcaemia in asphyctic infants might be explained by a decreased concentration of 1 alpha, 25-dihydroxy-vitamin D3 following reduced 1 alpha-hydroxylation in the kidney as a consequence of anoxia during perinatal asphyxia.

Asphyxia Neonatorum↗

Free calcium ion concentration in pregnancy. A longitudinal study on 22 normal pregnant women.

302 samples from 22 normal pregnancies were frozen and kept for the analysis of free calcium ion concentration [Ca2+](7.4) at 37 degrees C and pH 7.40, after equilibration with CO2. Individual regressions were performed, and the concentration was found to increase slightly but significantly (5%, p less than 0.005) with the progress of the pregnancy. This increase excludes hypocalcemia as the cause of parathyroid overactivity during pregnancy, and a higher set point of the parathyrin (PTH) secretion is suggested.

Calcium↗

Ionized calcium analyzer with a built-in pH correction.

We describe a new semi-automated apparatus for simultaneously measuring the concentration of free calcium ion and of hydrogen ion (pH) at 37 degrees C. The sample volume is 110 microL. In addition to the actual values for these concentrations in the sample, the apparatus calculates the concentration of free calcium ion at pH 7.40. Mean values for serum from 51 fasting bedridden patients without calcium metabolic disorders and 64 fasting hospital employees were 1.192 and 1.232 mmol/L, respectively, with SD of 0.042 and 0.040 mmol/L, respectively. The within-series analytical SD was 12 mumol/L and the day-to-day SD of the pH-corrected concentration of free calcium ion was 21 mumol/L, as calculated from measurements made on a serum pool after equilibration with a CO2--air mixture. The mean dependency on pH as determined in 120 consecutive patients' sera equalled the built-in pH correction. The accuracy was evaluated by comparison with other calcium ion-selective electrodes.

Blood↗

Binding of the chromium-ethylenediaminetetraacetic acid complex (CrEDTA) to human albumin.

The renal plasma clearance of the 51Chromium labelled complex with ethylenediaminetetraacetic acid ([51Cr]EDTA) underestimates that of inulin by 5-15%. Interaction of the anionic CrEDTA with polyanions in the glomerular filter and tubular reabsorption may add to the difference. A re-examination of the protein binding of CrEDTA showed that the protein binding is not negligible, because following ultrafiltration in vitro, the molality of CrEDTA was 5% lower in the ultrafiltrates than in the retentates. With a correction for the distribution of small ions this indicates at least 10% binding to human albumin. pKA = 7.36 was found for the equilibrium CrEDTA(H2O)- in equilibrium with CrEDTA(OH)2- + H+. One CrEDTA molecule carries one or two negative charges at near physiological pH. Renal plasma clearance of [51Cr]EDTA may be corrected to glomerular filtration rate (GFR) by multiplication with 1.10.

Albumins↗

Measurement of free calcium ion in capillary blood and serum.

We describe a new calcium ion-selective electrode for measurement of the substance concentration of free calcium ion [Ca2+] in the plasma phase of whole blood and in serum at 37 degrees C. A sample volume of 50 microliter suffices to obtain simultaneous values of pH and [Ca2+]. We found the within-series analytical standard deviation for serum to be 0.013 mmol/litre (CV, 1.1%) and day-to-day precision to be 0.022 mmol/litre (CV, 1.7%). The reference interval for [Ca2+] (at pH 7.40) in serum was found to be 1.184 +/- 0.054 mmol/litre (2 SD) from measurements on sera from 121 healthy blood donors. Measurements on capillary blood from 29 healthy volunteers gave a mean (+/- 2 SD) value for [Ca2+] (at pH 7.40) of 1.22 +/- 0.072 mmol/litre.

Bicarbonates↗

Albumin/calcium association at different pH, as determined by potentiometry.

Calcium binding by albumin was determined potentiometrically at physiological ionic strength and temperature as a function of pH. The binding data indicate at least 30 different binding sites with different association constants and different H+ interaction. One site appears to be responsible for the major binding at physiological pH and substance concentration of free calcium, together with three other sites that bind with less affinity.

Calcium↗

On the safety of using stored bank blood for chronic hemodialysis patients.

Red cells stored either for 3 days or 2 weeks were equally susceptible to lysis during in vitro dialysis. Furthermore, the small increases in plasma hemoglobin during hemodialysis of 10 patients were independent of transfusion. We examined the patients during three separate hemodialyses: one without transfusion, one with transfusion of three units of red cells stored for less than 5 days, and one with transfusion of red cells stored for 2 weeks. The mean concentration of hemoglobin in plasma increased from 0.7 to 3.6 mumol per l (p less than 0.01), and it was normal again after 2 days. No significant changes occurred in the mean concentration of haptoglobin in plasma. The results indicate that red cells stored for 2 weeks are not more prone to lysis than those stored for less than 5 days. Consequently, we recommend a storage interval of less than 2 weeks, instead of 5 days, for blood transfused to chronic hemodialysis patients.

Blood Banks↗

Parameter estimation in six numeric models of transperitoneal transport of glucose.

Six competing kinetic models of transperitoneal glucose transport were formulated and validated. The models were designed to elucidate the presence or absence of diffusive, nonlymphatic convective and lymphatic convective solute transport. The validation procedure included an assessment of theoretical and practical identifiability, goodness of fit, residual error analysis, and plausibility of parameter estimates. Experimental results were obtained from 21 patients without diabetes. The validation procedure demonstrated that the model that only included diffusion was superior to the other models. Theoretically, both nonlymphatic convective and lymphatic convective transports might exist. However, neither the ultrafiltration sieving coefficient nor the lymphatic flow rate were practically identifiable, probably because any amount of glucose transported by nonlymphatic convective and lymphatic convective transport mechanisms was negligible compared with the amount transported by diffusion. Based on these results, there appear to be problems measuring convective solute transport parameters when the solute transport is in the dialysate-to-blood direction while the fluid transport is in the blood-to-dialysate direction.

Adult↗