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PubMed1992

Reference values for resistance index and pulsatility index of uteroplacental Doppler flow velocity waveforms based on 612 uneventful pregnancies.

Using a 4-MHz continuous-wave Doppler device, standard rates were established for resistance index (RI) and pulsatility index (PI) of uterine and arcuate arteries of 612 patients with uneventful pregnancies and deliveries. From 18 to 41 weeks of gestation, neither RI nor PI of uterine or arcuate arteries proved to vary with gestational age, maternal heart rate, or maternal age. By contrast, a significant effect of placental location on the measurement results was found in both uterine and arcuate arteries. The differences between measurements on the placental or opposite site are more distinct in arcuate than in uterine arteries. Taking the 90th percentile as a localization gauge, cutoff levels of 0.52 (RI) and 0.98 (PI) were found in uterine arteries. In arcuate arteries, cutoff levels of 0.45 (RI) and 0.82 (PI) were found on the placental site or with a placenta without lateralization. On the nonplacental site of a lateralized placenta, the cutoff levels were 0.51 (RI) and 0.92 (PI).

Blood Flow Velocity↗

PubMed1983

Plasma lecithin:cholesterol acyltransferase -- reference values and effects of xenobiotics.

Plasma lecithin:cholesterol acyltransferase (LCAT) has been measured by an enzymatic method. We did not observe any significant sex variations, but age variations were found. In females, LCAT activities are stable up to 40 years (60 mumol . 1.1 . h-1 at the 50th centile). Also, from 50 years the median increased progressively to 76 mumol . 1-1 . h-1. In males, the activity increased from 52 to 71 mumol . 1-1 . h-1 at the 50th centile in two age groups (15-20 years and 50 years). The effect of some xenobiotics on LCAT activity was studied. We observed an increase in activity of 33% in males when the daily alcoholic beverage consumption ranged from 0 to more than 0.5 litre of wine or beer. LCAT activity increased in children who were treated with hypolipidemic drugs (fenofibrate, Lipanthyl). In boys, the mean enzyme activity increased to 35% (p less than 0.05). The increase was greater in girls (75%, p less than 0.01). Treatment with anticonvulsant drugs gave a decrease in LCAT activity of 32-46%.

Adolescent↗

PubMed1995

Color Doppler imaging of basal cerebral arteries: normal reference values and clinical applications.

Transcranial color-coded duplex ultrasonography is a new diagnostic procedure allowing the visualization of major intracranial vessels. The purpose of this report is to describe this method and to evaluate its practical potential in the routine examination of basal cerebral arteries. The results from the examination of 96 patients are presented. By means of color coding of Doppler frequencies, the major intracranial vessels were identified by nature of their anatomic location with respect to the echogenic brainstem structures in all subjects. The average maximal systolic velocity was, in the middle cerebral artery, 108 +/- 15 cm/s; in the anterior cerebral artery, 96 +/- 15; in the posterior cerebral artery, 76 +/- 16; and in the basilar artery, 59 +/- 17 cm/s. The determination of the angle between the ultrasonic beam and the examined vessel improved the accuracy of flow velocity measurements in comparison with conventional transcranial Doppler ultrasonography. The exact measurement of blood flow velocity in several segments of the visualized vessel proved helpful in the assessment of pathologic findings, especially in differentiation between a stenosis of the intracranial vessel and a vasospasm.

Adult↗

PubMed1985

Reference values of blood components related to fuel metabolism in children after an overnight fast.

The interrelation between blood components, involved in fuel metabolism, and age, sex and glucose was studied in 72 control children (26 girls and 46 boys, aged between 3 and 15 yr) after an overnight fast (14 h). Glucose, lactate, pyruvate, triglycerides and cholesterol are age-independent. Alanine is positively correlated, whereas beta-hydroxybutyrate, acetoacetate and NEFA's are negatively correlated with age. With respect to blood sugar, acetoacetate, NEFA's and cholesterol are glucose-independent. Lactate, pyruvate, alanine and triglycerides are positively correlated with glucose, and beta-hydroxybutyrate--and total ketone bodies--are negatively correlated with glucose. Except for triglycerides, no differences in the concentrations of the above mentioned blood substrates are seen between boys and girls. These data demonstrate that after an overnight fast lipolysis and ketogenesis already are active in young children, probably related to inadequate gluconeogenesis and improvement of carbohydrate regulation with age.

3-Hydroxybutyric Acid↗

PubMed2006

Mast cell tryptase in postmortem serum-reference values and confounders.

We have investigated the effects of some factors suspected of inducing spuriously increased tryptase concentrations, specifically sampling site, conjunctival petechial bleeding and prone position at the time of death as indicators of premortem asphyxia, and resuscitation efforts by external cardiac massage. Tryptase was measured in blood from the femoral vein in 60 deaths: 39 control cases who died rapidly (within minutes) from natural causes (sudden cardiac death and acute aortic dissection), 16 with death caused by prolonged asphyxia (traumatic compression of the chest and suffocation due to body position or smothering), and five anaphylactic deaths. In 44 of these cases, tryptase was measured in both heart and femoral blood. Mast cell tryptase was analyzed with a commercial FEIA method (Pharmacia Diagnostics AB, Uppsala, Sweden) measuring both alpha- and beta-tryptase. Assuming that tryptase values in the control group were gamma distributed, we calculated the upper normal limits for tryptase concentrations in femoral blood. It was found that 95% of the controls had values below 44.3 mug/l (femoral blood), SD 5.27 mug/l. All but one of the anaphylactic deaths had tryptase concentrations exceeding that limit. Tryptase was significantly elevated in femoral blood from anaphylactic deaths (p<0.007), compared with the controls. Also, in the cases where death had occurred due to asphyxia tryptase was elevated in femoral blood (p<0.04). A significant difference in tryptase concentrations was seen between blood from the heart and the femoral vessels (p<0.02) in the whole material (n=44). Tryptase concentrations in femoral blood were not influenced by prone position at death, or resuscitation efforts. It is concluded that asphyxia premortem seems to affect tryptase concentrations, that postmortem tryptase measurements should be done in serum from femoral blood, and that the normal upper limit, covering 95%, is 44.3 microg/l.

Adolescent↗

PubMed1981

Reference values for respiratory function tests in males: prediction formulas with tobacco smoking parameters.

Prediction equations for respiratory function tests were obtained by multiple regression of data from 263 healthy males. The material was evenly distributed in the ages 20-70 years, about one third each of non-smokers, smokers and ex-smokers. Measurements were done of lung volumes (with body plethysmograph), airways resistance, ventilatory capacity including flow-volume registration, gas distribution and closing volume, transfer factor and static elastic recoil pressures of the lung with calculation of static compliance. The parameters age, height, weight, years of tobacco smoking and grams of tobacco smoked each day showed significant correlation with the outcome of the test in most of the respiratory function tests. Therefore a set of basic regression equations including these parameters were calculated. In addition an 'extended' set of equations was calculated for prediction of some tests with inclusion of nonlinear terms and the parameter 'years of abstinence from smoking.' The reduction in variance which followed inclusion of tested parameters was moderate (20-69%). There were significant differences between results of the present study and several previously published regression formulas.

Adolescent↗

PubMed2003

Neural networks for the prediction of spirometric reference values.

Normal lung function values are conventionally calculated according to prediction equations. The primary objective of this study is the development of a different method for the prediction of FVC and FEV1 parameters, in order to achieve better correlation of the predicted values to the real ones. Using a sample from the Greek elderly population that was separated into two groups (a training and a testing one), a number of artificial neural networks were trained. Considering that men and women were studied separately and that two parameters (FVC, FEV1) were the target of the study, four cases came up. In each case two neural networks were trained using different transfer functions, number of neurons and number of layers. When passing the inputs of the testing data set to the trained networks it was found that the outputs were well correlated with the corresponding measures of the sample. Furthermore, the match with the sample, for a number of neural networks developed, was better compared to the matches of Baltopoulos et al. study that used the same sample for developing prediction equations. This high match allows the potential use of neural networks for predicting not only FVC and FEV1 but also other spirometric parameters.

Aged↗

PubMed1999

Improved extraction procedure and RIA for determination of arginine8-vasopressin in plasma: role of premeasurement sample treatment and reference values in children.

We optimized an RIA for measurement of arginine8-vasopressin (AVP) in plasma by use of 100-mg Isolute C18 columns for extraction, addition of a preincubation step, and use of maximal dilution of a commercially available antiserum. The detection limit was 0.06 ng/L when 0.5 mL of acidified plasma was extracted. The within- and between-run CVs (n = 16) at physiological concentrations were 5.8-10. 2% and 6.5-11.7%, respectively. Prolonged storage of blood at 25 degreesC, but not at 4 degreesC, led to a significant increase in measured plasma AVP concentrations. When plasma samples were prepared at several centrifugation speeds, plasma AVP was significantly correlated with the platelet count (r = 0.899; P <0. 001). This emphasizes the need for careful sample preparation to avoid contamination of plasma with platelet-bound AVP. Basal plasma AVP in 203 children and adolescents (105 males and 98 females; ages, 1 day to 18 years) averaged 1.1 +/- 0.6 ng/L. There was no significant difference between males and females and no correlation with age. In 16 healthy adult controls, plasma AVP averaged 1.0 +/- 0.5 ng/L.

Adolescent↗

PubMed2004

Aerobic and functional capacity in a group of healthy women: reference values and repeatability.

Twenty-five randomly selected, low or moderately fit and healthy women (22-44 years) rated their perceived physical capacity and performed an incremental cycle exercise test with respiratory gas analysis. The aerobic and functional capacity did not decrease with age. However, tauVo(2) increased with age. The mean value of the perceived physical capacity was 10 metabolic equivalents and that of Vo(2max) 2075 ml min(-1). The increasing anaerobic metabolism was determined at three points DX (where the rate of Vco(2) increase just exceeds the rate of Vo(2) increase), PX (where Vco(2)/Vo(2) = 1.0) and PQ (where ventilation increase disproportionately in relation to Vco(2)). The mean Vo(2) (% of Vo(2max)) at DX, PX and PQ were 1263 (63%), 1528 (73%) and 1620 (78%) ml min(-1), respectively. The mean value of deltaVo(2)/deltaW was 10.2 ml min(-1) W(-1) while that of tauVo(2) was 0.578 (age) + 15.6. Ten women performed a test and re-test on two consecutive days, and eight of these performed another re-test 4 weeks later. The repeatability was analysed and the variations were expressed as 2 SD of the differences between the tests. The variation was greater for the 4-week re-test than the day-to-day re-test regarding Vo(2max), o(2) at DX, PX and PQ, deltaVo(2)/deltaW and HR. The variation in Vo(2max), PX and deltaVo(2)/deltaW for the 4-week re-test was more than twice that of the previously reported 4-week variation for men. The considerable variation, especially for 4-week re-testing for women should be considered when evaluating the effects of exercise and rehabilitation.

Adult↗

PubMed1990

Reference values of hemostasis related factors of healthy Japanese adults. I: Circadian fluctuation.

The circadian fluctuation of hemostasis related parameters was examined on 16 healthy Japanese adults (male 9, female 7). Twenty one parameters were measured in this study, i.e. fibrinogen, the activity of F.II, F.V., F.VII, F.VIII, F.IX, F.X., F.XI, F.XII, antithrombin III, plasminogen, alpha 2-antiplasmin, as well as the antigen level of F.IX, von Willebrand Factor, protein C, tissue-type plasminogen activator (tPA), plasminogen activator inhibitor-1 (PAI-1), beta-thromboglobulin, platelet factor 4, fibrinopeptide A, plasmin-alpha 2-antiplasmin complex and FDP. Fluctuation was not significant in almost all of the parameters except F.VIII, F.IX, beta-thromboglobulin, platelet factor 4, tPA and PAI-1. Although the fluctuations of F.VIII, F.IX, beta-thromboglobulin and platelet factor 4 were statistically significant, they remained within the normal ranges. On the other hand, tPA and free PAI-1 showed significant circadian fluctuation, of which levels were highest at 9:00. It was postulated that the significant circadian fluctuation of fibrinolytic activity will be regulated by the balance between tPA and PAI-1 in plasma.

Adult↗

PubMed2004

[Reference values of 24-hour ambulatory blood pressure in healthy children by height].

UNLABELLED: The aim of the work was to prepare the percentile curves for blood pressure measured by 24-hour ambulatory blood pressure monitoring (ABPM) in children by height. MATERIAL AND METHODS: ABPM was performed in 852 healthy children aged 7-17 years (433 girls, 419 boys). Systolic (SBP) and diastolic (DBP) blood pressure was measured for 24 h, including the period of activity and rest, using BR-102 Schiller Poland LTD monitor and Quiet Tycos ABPM, USA. The mean number of readings over the 24-hour period was 58.4+/-4. RESULTS: The mean SBP in the group of girls with height 120-172 cm increased from 102.2+/-5.5 to 121.0+-7.8 mmHg, and in the group of boys with height 120-180 cm and over from 103.7+/-5.7 to 123.7+/-6.2 mmHg. A strong positive correlation between the height and SBP and weak with DBP was noted. The percentile charts for blood pressure in children aged 7-17 by height were prepared. CONCLUSIONS: The mean systolic blood pressure decreased at night more than diastolic blood pressure, independently of height. Systolic blood pressure was stronger correlated with the height than with the age.

Adolescent↗

PubMed1988

Single breath nitrogen test in an epidemiologic survey in North Italy. Reliability, reference values and relationships with symptoms.

The usefulness of single breath nitrogen test (SBN2) was evaluated in a cross-sectional epidemiologic survey on a general population sample (n = 3,289) of North Italy. Each subject was submitted to CNR standardized questionnaire and to lung function testing using automated equipment (Hewlett-Packard 47804S). Acceptable closing volume (CV) and slope of alveolar plateau (DN2%/L) tracings were performed by only 1,370 and 1,982 subjects respectively, in comparison with the 2,638 diffusing capacity and the 3,079 forced vital capacity acceptable maneuvers. Prediction equations were computed on normal subjects for CV indices, with the exception of DN2%/L: they were similar to those found in other studies. Significant differences among smoking categories were found for all the SBN2 parameters in males, but only for DN2%/L in females. The latter was also able to distinguish either subjects with airway obstruction from those without it or symptomatic from asymptomatic individuals, but DN2%/L did not give more information than Vmax75, a sensitive index of flow volume curve. Our results suggest that the place of SBN2 in large scale epidemiologic testing has not been justified.

Adolescent↗

PubMed2001

Hip function in patients >55 years old: population reference values.

The purpose of this study was to establish population values for hip function for patients of different ages using the validated WOMAC scoring system and the traditional Harris hip scoring system. A random sample of 184 individuals who had no prior history of hip or knee pain or pathology was evaluated. The average WOMAC scores for pain, function, and stiffness were 0.01, 1.8, and 0.4. The average Harris hip score was 94 +/- 8.2. No significant correlation was noted between the summary WOMAC score, the WOMAC stiffness or pain subscales, or the overall Harris hip score for any of the 3 age groups studied. Patients with complaints in other joints, such as the back and neck, had lower WOMAC and Harris hip scores. Adults who are healthy and do not have a prior history of hip or knee pathology do not show a significant decline in hip function as they grow older. A deterioration in the function of a total hip arthroplasty over time cannot be attributed solely to the aging process.

Aged↗

PubMed2002

Reference values for morning salivary cortisol concentrations in healthy school-aged children.

INTRODUCTION: In children, sensitive, specific, pain-free sampling methods are important. An alternative is salivary sampling. Our knowledge about steroid levels in saliva and plasma in school-aged children and during puberty is sparse and contradictory. AIM OF THE STUDY: To estimate salivary cortisol concentrations in healthy school-aged children and relate the concentrations to age, sex, stage of puberty and adult values. PATIENTS AND METHOD: Saliva was collected in Salivette tubes from 210 boys and 176 girls aged 7-15 years, and from four adults, between 08.00 and 09.00 h. The tubes were centrifuged and then frozen at -20 degrees C until analysed by a commercial RIA-cortisol kit. RESULTS: Salivary cortisol was measurable in all infants. Boys and girls had nearly the same median concentrations, 8.8 versus 8.6 nmol/l, but girls had a higher maximal level, 53.9 compared to 33.2 nmol/l in boys. The median concentration was lower in 7-9 year-old children, 7.2 in boys and 5.7 nmol/l in girls, compared to 10-12 year-old children, 11.5 in boys and 10.9 nmol/l in girls (p <0.001). The median concentrations in most age groups were lower than in adults. Salivary cortisol concentration was dependent on stage of puberty. CONCLUSION: Salivary cortisol was measurable in the morning in school-aged children and the median concentration was dependent on age, stage of puberty, but not on sex.

Adolescent↗

PubMed1994

Measurement of retinal hemodynamics with scanning laser ophthalmoscopy: reference values and variation.

High resolution video fluorescein angiography using scanning laser ophthalmoscopy allows the assessment of retinal macro- and microcirculation. Data on the retinal macrocirculation were obtained from 221 healthy subjects. The data were derived from estimations of the arm-retina time, the arteriovenous passage time and mean arterial dye velocity, characterizing the passage of fluorescein to the eye, the mean arterial plasma velocity, and the arteriovenous passage through the entire vascular bed of one segment. Additionally, the transit of hypofluorescent segments in the capillary macular network were measured in 90 healthy subjects. These parameters provide a wide range of information for understanding the physiology of healthy and diseased eyes. Fundamental for all interpretations is the knowledge of the physiological variations. In the present study the inter- and intraindividual variability of retinal hemodynamics in healthy volunteers were assessed. The interindividual variation was 23.8% for the arm-retina time, 20.7% for the arteriovenous passage time, 23.7% for the mean arterial dye velocity, and 14.2% for the capillary flow velocity; the coefficient for variation, characterizing the intraindividual variation, was 26.6%, 15.6%, 16.7%, and 7.9%, respectively. The knowledge of the inter- and intraindividual variation of retinal blood flow indices allows for a priori power estimations for pathophysiologic and pharmacological studies.

Adult↗

PubMed1991

[Experience with computer-assisted EMG analysis: reference values for four muscles].

The characteristics of a newly developed computerized EMG-analysis system are lined out. The analysis steps include segmentation and parametrization of digitized EMG segments followed by automatic classification of single potentials into motor units. Comparison of parameters is used rather than a template matching algorithm for classification. For each motor unit a set of parameters can be computed in addition to duration and amplitude. Normative data are given for four muscles. 60 normal volunteers (50% female, 50% below age 50) were recorded from for each muscle. The recording conditions required to move the electrode until a motor unit could be recorded with its individual maximum. Furthermore, it was attempted to attain the maximum discharge rate of a particular motor unit. A highly significant correlation of the amplitude of the motor unit potentials with age was found for all four muscles. For the duration of the potentials a correlation with age was found only for the M. ext. digitorum brevis. Significant sex differences were found for nearly all parameters and all muscles. Pairwise comparisons of the muscles revealed significant differences of all muscles. The analysis showed, that a muscle can be regarded pathological if more than two of a total of seven recorded motor units show pathological parameters.

Age Factors↗

PubMed1997

[Reference values in vision development of infants with clinical use of the Teller Acuity Cards].

BACKGROUND: Using Teller Acuity Cards (TAC) for clinical visual testing, the question arose how our measurements fitted in the different standard tables of the producer's hand-book. In addition, we wanted to investigate how reliable the measurements of newborn and infants were and what the examination success rate under clinical conditions was. METHODS: At the paediatric clinic of the University of Erlangen, we tested the binocular grating acuity of 98 infants up to the age of one year, using the complete set of Teller acuity cards. In addition, 41 of the children underwent a monocular vision test. RESULTS: 1. Theoretical: At first we calculated conversion data for our card set. Using this conversion scale from cy/cm in cy/deg and the corresponding vision equivalent we produced our own standards for the development of grating acuity up to the age of one year. 2. Clinical: In 3-5 min per clinical examination we could determine for 90.8% of the patients a vision equivalent. The reliability of the results was age dependent and was at its best at the age of 5-11 months. The reliability was also very dependent on the duration of the test and the number of test runs. This resulted in a limited card choice for each age group.

Age Factors↗

PubMed2000

Reference values for radiological evaluation of cervical vertebral body shape and spinal canal.

BACKGROUND: Defining normal values is essential for reliable evaluation of growth disturbances. Previous studies of the cervical spine have mainly focused on the sagittal canal diameter and interpedicular distances. Values for vertebral body height and depth have been published only in adult men and cadavers. OBJECTIVES: To define normal values for vertebral body height (H)/vertebral body depth (D) ratio (H/D ratio) and sagittal canal diameter (S)/ vertebral body depth ratio (S/D ratio) in C2-7. MATERIALS AND METHODS: Lateral cervical spine radiographs were available from 441 children and 192 adults. Subjects' ages varied from newborn to 39 years. Vertebral body height and depth and sagittal canal diameter were measured and ratios were calculated. This was a cross-sectional and retrospective study. RESULTS: Vertebral bodies grow relatively more in height than in depth, most actively at puberty. At all levels, the H/D ratio remains below 1, indicating that vertebral body depth is greater than height. The SD ratio is quite stable until 7-8 years of age and then it starts to decline slowly. CONCLUSIONS: When estimating platyspondyly, the age of the patient must be taken into consideration because vertebral body height is lower in children. Growth of the spinal canal declines after 7-8 years of age.

Adolescent↗