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At least 901 records · Page 50Linked to original sources
PubMed1999

Determination of reference values for a novel ketoamine-specific fructosamine assay for assessment of diabetic glycemic control.

BACKGROUND: Intensive monitoring to improve glycemic control is essential for effective management of diabetes and reduction of long-term morbidity and pathology. Measurement of glycated serum proteins (fructosamine) allows more frequent assessment (monthly) of glycemic control than the 2- to 3-month window of the traditional glycated hemoglobin (HbA1c) assay. In response to concerns about assays designed to measure glycated serum proteins based on the nitroblue tetrazolium (NBT) methodology, a novel assay to measure glycated serum proteins has been developed based on the specific oxidation of the ketoamine bonds within the glycated proteins. METHODS: Reference range values for this new, enzymatic glycated-serum-protein assay (GlyPro; Genzyme Corporation, Cambridge, MA) are reported. RESULTS: The GlyPro reference range is lower and shows close correlation with ranges reported for the NBT assay. The 95% overall reference range was 122 to 236 mumol/L. CONCLUSIONS: GlyPro is a reliable, accurate assay and correlates well with the NBT assay for the measurement of glycated serum proteins. The assay may be useful in the short-term assessment of diabetes control, a necessary complement to long-term control as assessed by hemoglobin A1c (HbA1c) assays.

Adult↗
PubMed1992

Reference values for early markers of renal damage.

In addition to the difficulties related to the definition of a reference population and hence of reference limits, special methodological problems have to be dealt with when early markers of renal damage are applied to monitor groups at risk. The urinary excretion of both high and low molecular weight proteins, as measured by sensitive immunoassays, is routinely applied in health surveillance programmes aimed at preventing the occurrence of adverse renal effects resulting from exposure to nephrotoxic chemicals, among which are several metals. Owing to the large intra-individual variability experimentally demonstrated for all indicators of renal impairment, carefully standardized sampling conditions must be adopted. At the individual level, repeated measurements should be performed before a diagnosis of renal disease or dysfunction is established. In fact, several physiological conditions may account for transient changes in renal function, leading to measured levels greatly exceeding reference limits.

Albuminuria↗
PubMed2002

Reference values of the bioelectrical impedance vector in neonates in the first week after birth.

OBJECTIVE: To determine the reference, bivariate, tolerance intervals of the whole-body impedance vector for healthy white neonates, we performed an observational, cross-sectional study in two university hospitals. METHODS: The impedance vector (standard, tetrapolar analysis at 50-kHz frequency) was measured in 163 consecutive subjects (87 boys and 76 girls) with postnatal ages of 1 to 7 d. Bivariate vector analysis was conducted with the resistance-reactance (RXc) graph method. RESULTS: The age-specific 95% confidence intervals of mean vectors and the 95%, 75%, and 50% tolerance intervals for individual vector measurements were plotted using R and Xc components standardized by the subject's crown-to-heel length (height). Mean vectors from the groups (1, 2, and 3 to 7 d) with overlapping 95% confidence ellipses were considered representative of only one age class of 1 to 7 d. The impedance vector distribution of neonates also was compared with healthy white children (1014 boys and 1030 girls, age 2-15 y) and adult subjects (354 men and 372 women, age 15-85 y) from the same geographic area. There was a definite, progressive, vector shortening from birth, through ages 2 to 15 y, toward the adults' vector position. CONCLUSIONS: We established the reference, bivariate, 95%, 75%, and 50% tolerance intervals of the impedance vector in the first postnatal week for healthy white neonates, with which the vectors from infants with altered body composition can be tested (free software is available from apiccoli@ unipd.it).

Adolescent↗
PubMed1987

Reference values for serum copper, ceruloplasmin and zinc and haematological indices for healthy nulliparous females.

Reference serum copper, ceruloplasmin and zinc values were established for 100 healthy white nulliparous students aged 18-23 years resident in Cape Town who had been taking low-dosage triphasic contraceptives for a minimum period of 3 months, and in 100 female students not taking contraceptives. The mean serum copper values were 26.5 +/- 4.2 mumol/l and 16.9 +/- 2.7 mumol/l for those taking and not taking oral contraceptives respectively; corresponding values for ceruloplasmin were 181 +/- 43.9 IU/ml and 110 +/- 22.7 IU/ml respectively. Both differences were statistically significant. Serum zinc values for those on contraceptives were 14.1 +/- 2.1 mumol/l and for the others 14.7 +/- 2.0 mumol/l. There were no differences in the haematological parameters except for a significantly higher mean corpuscular volume in females taking oral contraceptives. Of possible clinical significance in this student population are prevalence rates of 2.2% for anaemia (haemoglobin value less than 11.5 g/dl), 7% for iron deficiency (serum ferritin less than 12 micrograms/l) and 6.6% for iron depletion (serum ferritin 12-20 micrograms/l).

Adult↗
PubMed1998

Reference values of 5-aminolevulinate dehydrase and porphobilinogen deaminase in the Spanish population from Madrid.

5-Aminolevulinate dehydrase (ALA-D) and porphobilinogen deaminase (PBG-D) are cytosolic enzymes involved in heme biosynthesis. ALA-D activity is altered both genetically and by the action of various environmental factors, including exposure to lead. The activity of PBG-D is reduced in acute intermittent porphyria. The aim of this work is to establish the 95% reference range of the erythrocytic activity of ALA-D and PBG-D in a control population. ALA-D activity limits were 15.8 and 50.2 nmol of PBG/ml of red blood cells (RBCS) per minute. For the activity of ALA-D restored by addition of zinc and dithiothreitol ("restored ALA-D"), these limits were 44.1 and 86.5 units. It has been found that the "restored ALA-D"/ALA-D ratio is very useful for the evaluation of lead toxicity, and its 95% reference range was between 1.22 and 3.06. It has been demonstrated that the best method for measuring erythrocytic PBG-D is using PBG, but not ALA, as substrate; its 95% reference range was between 20.9 and 63.2 nmol of uroporphyrin/ml of RBCs per hour. Knowledge of these reference range values in a control population constitutes the basis for an accurate diagnosis of heavy metal intoxication and acute intermittent porphyria.

Adolescent↗
PubMedDate not supplied

Second trimester maternal serum hCG level in an Asian population: normal reference values by ultrasound dating.

OBJECTIVE: To establish normative data of maternal serum chorionic gonadotropin (hCG) during the second trimester in an Asian population. METHODS: We measured the maternal serum hCG levels in 17,955 normal singleton pregnancies between 15 and 21 weeks of gestation. The gestation age was estimated by measurement of fetal biparietal distance (BPD) in all cases. Median values of hCG at various gestational weeks were calculated and the values of hCG were converted to multiple of median (MoM). The incidences of low MoM value and high MoM value were also calculated. RESULTS: The mean and median values of hCG were 57,153 mIU/ml and 50,120 mIU/ml, respectively, at 15 weeks of gestation and then decreased to 30,898 mIU/ml and 26,226 mIU/ml, respectively, at 21 weeks. We found 8.6% and 9.4% of normal singleton pregnancies have hCG MoM values >2.0 MoM and <0.5 MoM, respectively. CONCLUSIONS: Our report provides a normal reference data of second trimester maternal hCG levels by ultrasound dating in an Asian population.

Chorionic Gonadotropin↗
PubMed1983

Variation with age of reference values for P-cobalamins.

P-cobalamins were recorded on plasma from 279 persons (age interval 20-80 years) who participated in a population survey. The values obtained showed a decrease in the mean and a broadening of the reference interval with age. The justification of employing one reference interval, 200-650 pmol/l, is discussed.

Adult↗