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At least 919 records · Page 51Linked to original sources
PubMed2005

Comparison of different reference values of fetal blood flow velocity in the middle cerebral artery for predicting fetal anemia.

OBJECTIVES: To compare different normal reference ranges of fetal blood flow velocity in the middle cerebral artery for predicting fetal anemia. METHODS: Eight reference ranges of either middle cerebral artery peak or time-averaged mean velocities were compared using the area under the receiver-operating characteristics (ROC) curve for 113 fetal blood samples from 60 women at risk of fetal red blood cell alloimmunization. RESULTS: The areas under the ROC curves of the different ranges were not significantly different but there were marked differences in sensitivity (range, 7.14-91.78%) and specificity (range, 31.25-96.88%) with the currently used cut-offs. Except for Mari's range, the best theoretical cut-offs, defined as those having the best sensitivity with the best specificity, differed from those in current use, especially when using time-averaged mean velocity. CONCLUSIONS: Any of the previously reported reference ranges perform well in the non-invasive prediction of fetal anemia. However, with the exception of Mari's curve, the currently employed cut-offs for predicting fetal anemia should be changed, some of them markedly, in order to provide reliable support for clinical decisions.

Blood Flow Velocity↗
PubMed1994

Hemoglobins S and C: reference values for glycohemoglobin in heterozygous, double-heterozygous and homozygous subjects, as established by 13 methods.

Glycohemoglobin (gly-Hb) reference ranges of non-diabetic adults with HbAA (n = 17), HbAS (n = 37), HbAC (n = 22), HbSC (n = 8), HbSS (n = 6) and HbCC (n = 3) were determined by 13 methods, based on affinity chromatography, HPLC, electrophoresis and immunoassay. Gly-Hb of subjects with HbAS and HbAC can be measured without major difficulties by most methods. Some give rise to absolute gly-Hb differences > or = 1% compared with subjects with HbAA. Measurement of HbA1c/total Hb cannot be recommended. Some HPLC and immunoassay methods cannot measure gly-Hb in subjects with HbSC, HbSS and HbCC, whereas others may suffer from interference. Most methods showed low gly-Hb, reflecting increased erythrocyte turnover. Use of special reference ranges requires previous knowledge of the condition (affinity chromatography and immunoassay) or separation of gly-Hb and its precursor Hb (HPLC and electrophoresis). Interpretation is, however, not recommended because of the numerous factors that determine erythrocyte turnover.

Adult↗
PubMed1997

Reference values for retinol, tocopherol, and main carotenoids in serum of control and insulin-dependent diabetic Spanish subjects.

To establish reference ranges for use in clinical and epidemiological studies, we determined concentrations of retinol, alpha-tocopherol, beta-carotene, alpha-carotene, beta-cryptoxanthin, lutein, zeaxanthin, and lycopene in 450 Spanish control subjects and 123 Spanish patients with insulin-dependent diabetes mellitus (IDDM). Results were grouped according to sex, and samples were collected throughout the year. Concentrations of retinol were significantly lower and beta-carotene and alpha-carotene were higher in women than in men, both in controls and IDDM subjects, whereas beta-cryptoxanthin concentrations were higher only in control women. Conditional logistic regression analysis showed that retinol, beta-carotene, and lycopene were the variables associated with diabetes. In comparison with other populations, our controls showed, in general, ordinary concentrations of retinol, comparatively low beta-carotene and high beta-cryptoxanthin concentrations, and a relatively high alpha-tocopherol/ cholesterol ratio.

Adolescent↗
PubMed2006

Reference values for whole body and cerebral multi-frequency bio-impedance data in neonates less than 12 h postpartum.

Multiple frequency bio-electrical impedance analysis (MFBIA) may be useful for monitoring fluid balance in newborn infants or to provide early prediction of the outcome following perinatal asphyxia. A reference range of data is needed for identification of babies with abnormal impedance values. This was a cross-sectional observational study in 84 term and near-term healthy neonates less than 12 h postpartum. Whole body and cerebral MFBIA measurements were performed at the bedside in the post-natal ward. Gestational age, post-natal age, gender, birthweight, head circumference and foot length measures were recorded. Reference values for impedance at the characteristic frequency (Z(C)) and resistance at zero frequency (R(0)) are reported for whole body and cerebral impedance. Significant correlations (p < 0.05) were observed between whole body impedance and birthweight, footlength and head circumference. Females had a significantly higher whole body R(0) than males. Cerebral impedance did not correlate significantly with any of the demographic measures and there were no gender differences observed for cerebral impedance. The reference range for whole body multi-frequency bio-impedance values in term and near-term infants within the first 12 h postpartum can be calculated from the footlength (FL) using the following equations: Z(C) = (942.9 - 4.818*FL) +/- 124.6 Omega; R(0) = (1042 - 4.520*FL) +/- 135.5 Omega. For cerebral impedance the reference range is 29.5-48.7 Omega for Z(C) and 33.7-58.0 Omega for R(0).

Body Composition↗
PubMed1993

Comparison between reference values for 201thallium uptake and washout from the myocardium after exercise and after dipyridamole.

A slow washout of 201Thallium has a high diagnostic and prognostic value for coronary artery disease. The aim of the present work was to contribute with reference data on 201Tl uptake and washout from the myocardium. With a quantitative method using circumferential profiles and interpolative background subtraction we performed 201Tl myocardial imaging in two groups of subjects with a low probability of coronary artery disease. Washout in per cent is defined as (1-D/I).100, where D is the delayed uptake rate and I the initial uptake rate. In group A (n = 16) myocardial hyperaemia was induced by maximal exercise, in group B (n = 15) by intravenous infusion of dipyridamole. In group A, the mean washout was 52%, and in group B it was 34% (P < 0.001). The delayed uptake rate D was significantly higher after dipyridamole, 58.4 cps, than after exercise, 44.5 cps (P < 0.05). There was no significant differences in I between the two groups. The findings regarding D and I explain that the washout is slower after dipyridamole than after exercise, as the mean D/I ratio was 0.48 in group A and 0.66 in group B (P < 0.001).

Adult↗
PubMed1994

[The reference value of plasma glucose in individuals over 65 years].

The characteristics of plasma glucose in individuals aged over 65 years was investigated by analysis of age dependent changes of fasting and post glucose (75 g) load values in population based studies and some follow-up studies. Institutional differences were surveyed in central laboratory of institutions which joined this study and found that differences were the range of +3.0-3.5% from the mean glucose levels between 100-400 mg/dl. Therefore plasma glucose values around cutoff level should be confirmed by repeated determinations for reaching final diagnosis. The reference interval of plasma glucose does not differ in an age-dependent manner. We may use the reference interval proposed by the Committee of Diagnostic Criteria of Diabetes Mellitus of Japan Diabetes Society for adult individuals. Cases of diabetes diagnosed before 65 years old should be judged by the adult criteria. However, those who were not diabetic before age 65 and were found to be hyperglycemic after that age can be diagnosed classifying as follows: (1) Diabetes should be diagnosed in individuals with a fasting plasma glucose of 140 mg/dl or more and 2 hours after glucose (75 g) of 240 mg/dl or more. Those with some symptoms suggesting diabetes and either 140 mg/dl more or fasting or 240 mg/dl or more 2 hours post 75 g glucose load can also be diagnosed as diabetes.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1996

Age-dependent reference values of urinary porphyrins in children.

To establish age-dependent reference ranges for the 3 major urinary porphyrins, uroporphyrin, coproporphyrin I and coproporphyrin III, concentrations were measured in random urine specimens from 198 children aged 0.5 to 16 and 18 new-borns by HPLC. All three porphyrins displayed unique age-dependencies. The highest coproporphyrin I concentration was observed in the new-born period, which could be explained by a physiologically under-developed excretion system (via bile and faeces) for this particular porphyrin. Coproporphyrin III excretion reached its highest value in children between ages 1 and 2. Of the three porphyrins, coproporphyrin III concentration showed the closest correlation with the total haem synthesis in childhood. A relatively broad concentration range was found for uroporphyrin in all tested age-groups, the highest mean concentration being in the new-born period. Quantification of each individual urinary porphyrin enables the diagnosis of certain disorders which otherwise cannot be achieved by the total porphyrin determination. As an example of the clinical application of these reference ranges, a case of bronze baby syndrome is discussed.

Adolescent↗
PubMed1980

Reference values for cerebrospinal fluid glutamine concentration in infants.

We measured cerebrospinal fluid glutamine concentration in a reference group of 85 newborn to 30-month-old infants. All of the spinal taps were performed for the diagnosis of illnesses unrelated to hyperammonemia or hepatic encephalopathy. We also analyzed samples from patients with meningitis or cerebral hemorrhage, or who were receiving total parenteral nutrition. The mean glutamine concentration in cerebrospinal fluid in the reference group was somewhat lower than values reported for older children and adults. Values were significantly higher in patients with meningitis or cerebral hemorrhage and in those infants receiving total parenteral nutrition.

Age Factors↗
PubMed1997

A mathematical approach for estimating reference values for weight-for-age, weight-for-height and height-for-age.

Anthropometry is widely used to monitor infant growth and to estimate child nutritional status. Current evidence suggests that existent growth curves are not adequate for use with all infants and researchers sought to identify another data set suitable for development as a new international growth reference. In this article we cast about unconditional limits for growth monitoring from raw data on age, sex, height and weight. Anthrompometric data from children aged 1 to 9 years from two studies on malnutrition in Brazil was analyzed. Data on age, sex, weight, height and body mass index from 141 Amerindian children was used to develop mathematical models to predict percent of NCHS medians for weight-for-age, weight-for-height, and height-for-age using multiple linear regression. Data from 251 children in a non-indian seaside village was used for cross-validation. Six age-specific equations were obtained with coefficients of determination greater than 0.96. Coefficients of correlation between NCHS-derived and model-derived values into the validation data set were greater than 0.96 for weight-for-age, greater than 0.99 for weight-for-height, and near 1.00 for height-for-age. It remains to be seen if one can achieve universal linear models from more representative samples, using the approach described here. Perhaps establishing a mathematical relation among anthropometric data would result in absolute individual limits for growth monitoring. They may even be as important to infant nutritional assessment as growth reference values.

Aging↗