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PubMed2000

Blood plasma chemistries from wild mourning doves held in captivity.

Despite the extensive amount of research conducted on mourning doves (Zenaida macroura), no biochemical reference values exist for this species. Our objective, therefore, was to establish base line clinical chemistry reference values for mourning doves to assist with establishing clinical diagnoses. Wild mourning doves were captured 19 March 1996 to 8 August 1996, and 6 February 1998 to 12 May 1998; blood samples were collected from 382 mourning doves. Plasma biochemical values were established for glucose, sodium, potassium, chloride, enzymatic CO2, albumin, total protein, globulin, calcium, phosphorus, cholesterol, magnesium, aspartate aminotransferase (AST), gamma glutamyl transferase (GGT), lactate dehydrogenase (LDH), and uric acid. These reference values are invaluable for determining diagnosis of diseases of the gastrointestinal, hepatic, renal, cardiovascular, musculoskeletal, and endocrine systems.

Animals↗

PubMed2003

Erythrocyte superoxide dismutase, glutathione peroxidase and catalase activities in healthy male subjects in Republic of Macedonia.

OBJECTIVES: The study was aimed to establish the reference values for erythrocyte antioxidant enzymes, superoxide dismutase (SOD), glutathione peroxidase (GPX) and catalase (CAT) in healthy male subjects, as well as to detect their relation to age, cigarette smoking, moderate alcohol consumption, antiinflammatory drugs and supplements use and the possible correlation between individual parameters. BACKGROUND: Superoxide dismutase, glutathione peroxidase and catalase are the three main enzymes that control the biological effects of the reactive oxygen species (free radicals). METHODS: The authors have examined 111 healthy male blood donors aged 18-59 years. All studied enzymes were assayed in erythrocytes by manual techniques. The results were statistically evaluated by means of the ANOVA programme. RESULTS: The group of healthy individuals had a large dispersion of interindividual activities of antioxidant enzymes. Age, cigarette smoking, antiinflammatory drugs and dietary supplements use had no significant effect on the antioxidant enzymes activity. The activity of the enzymes showed normal Gaussian distribution. We established mean reference values for SOD, GPX and CAT activity. SOD negatively correlated with CAT (r=-0.199). CONCLUSIONS: We established the reference values for erythrocyte SOD, GPX and CAT activity in male subjects. The large dispersion of activities of the investigated enzymes in healthy individuals does not allow to make a standard use of these parameters in clinical practise without establishing "own reference values" for each laboratory. (Tab. 2, Fig. 4, Ref. 31)

Adolescent↗

PubMed2004

Partitioning of nongaussian-distributed biochemical reference data into subgroups.

BACKGROUND: The aim of this study was to develop new methods for partitioning biochemical reference data, covering in particular nongaussian distributions. METHODS: We recently proposed partitioning criteria for gaussian distributions. These criteria relate to proportions of the subgroups outside each of the reference limits of the combined distribution (proportion criteria) and to distances between the subgroup distributions as correlates of these proportions (distance criteria). However, distance criteria do not seem to be ideal for nongaussian distributions because a generally valid relationship between proportions and distances cannot be established for these. RESULTS: Proportion criteria appear preferable to distance criteria for two additional reasons: (a) The prevalences of the subgroup populations may have a considerable effect on stratification, but these are hard to account for by using distance criteria. Two methods to handle prevalences are described, the root method and the multiplication method. (b) Tied reference values, another complication of the partitioning problem, could also be hard to take care of using distance criteria. Some solutions to the problems caused by tied reference values are suggested. CONCLUSIONS: Partitioning of biochemical reference data should preferably be based on proportion criteria; this is particularly true for nongaussian distributions. Both of the described complications of the partitioning problem, the prevalences of the subgroups and tied reference values, are hard to deal with using distance criteria, but the proposed methods make it possible to account for them when proportion criteria are applied.

Clinical Laboratory Techniques↗

PubMed1994

Assessment of vitamin B2 status in performance athletes of various types of sports.

To determine the vitamin B2 supply, 62 athletes in various types of sports and 16 non-athletes were examined, using a weighed food record (7-day), alpha-EGR determination, microbiological blood, and HPLC urinary measurements. If the guidelines of 1.5 or 1.7 mg/day vitamin B2 or 0.6 mg/4,184 kJ (GRDA) are defined for adequate status, all sports groups (M +/- SEM) are above this level. The vitamin B2 blood concentrations show a range (mean) from 303-372 nmol/liter, which indicates that more than 90% of the athletes are above the reference value of 327 nmol/liter (mean). There is a correlation of r = 0.49 between the vitamin B2 intake (mean over 7 days) and the vitamin B2 blood level. Determination of vitamin B2 blood concentration is characterized by good precision (C.V. +/- 3.2%) and recovery (95.7%). The enzyme activation measurement (alpha-EGR) shows that all of the athletes are below the alpha-EGR reference value of < 1.50 (good supply). No significant correlations could be determined between alpha-EGR and vitamin B2 intake, blood concentrations, and urinary excretion. The measurement also shows high precision (C.V. 1.7%). The Vitamin B2 excretion in urine (mumol/g Cr.) was higher than the reference values for non-athletes in more than 90% of the athletes. There is a correlation of r = 0.89 between the vitamin B2 intake on the last day (Day 7) of the food record and the riboflavin excretion, and between vitamin B2 in blood and urinary excretion of r = 0.52. The C.V. of vitamin B2 urinary measurement using HPLC is 2.5%, with recovery of 98.2%. Combined measurement of vitamin B2 intake, blood concentration, and urine excretion appears to be a suitable procedure for determining the vitamin B2 status. Most of the performance athletes were sufficiently supplied with vitamin B2, compared to the reference values for non-athletes.

Adolescent↗

PubMed1985

[Mineral and trace elements in human urine].

Mineral and trace elements (Al, B, Ca, Cu, Fe, K, Li, Mg, Na, P and Zn) in 24 hour human urine samples from approximately 100 healthy persons (age between 20 and 50 years) were analysed by ICP (Inductively Coupled Plasma) and DCP (Direct Current Plasma) emission spectroscopy. The obtained values can be taken as "reference values" owing to the large number of individual samples. Mean values and the range of substance concentrations and substance excretion per 24 hours are given. Physiological reference values are reported for Ba, Sr and Ti, which are of particular interest in the field of occupational medicine; examples of increases in these three elements as a result of exposure at the work place are also given. Additionally some average values for Cd, Co, Ni and Pb have been measured by a voltammetric technique.

Humans↗

PubMed2005

Postmortem lung weight/body weight standards for term and preterm infants.

Assessment of lung development is a crucial component of the perinatal autopsy, especially in preterm infants. In current pathology practice, the diagnosis of lung hypoplasia in very premature infants (<28 weeks of gestation) is based on a lung weight/body weight ratio (LW/BW) of 1.5% or less. While useful to confirm the presence of marked pulmonary hypoplasia, the 1.5% threshold may be too stringent to detect more subtle degrees of pulmonary hypoplasia, as seen in association with rupture of membranes. The aim of this study was to establish reference values for postmortem LW/BW in preterm and term infants. To this end, we performed a retrospective analysis of fetuses and newborns (16-41 weeks of gestation) without known risk factors for pulmonary hypoplasia. Mean LW/BW ranged between 2.98-3.15% between 16-27 weeks, and decreased to 2.55% by 28-36 weeks and 1.79% at term. The 10th percentile for LW/BW was significantly higher in preterm infants (2.24% between 20-23 weeks, and 2.59% between 24-27 weeks) than in term infants (1.24% at >or=37 weeks, P < 0.01). We then correlated LW/BW of infants with risk factors for pulmonary hypoplasia with the newly established reference values. As expected, mean LW/BW of infants with congenital diaphragmatic hernia or severe renal anomalies was <1.5% (0.98% and 1.40%, respectively). Mean LW/BW of infants with prolonged (> 1 week) rupture of membranes (PROM) was 2.08%. Three of 12 (25%) preterm infants with PROM had pulmonary hypoplasia according to the traditional criteria (LW/BW <1.5%). However, an additional 4/12 (33%) infants with PROM had a LW/BW between 1.5% and the 10th percentile for age (2.2%), indicative of more subtle but potentially relevant pulmonary underdevelopment. In conclusion, we determined LW/BW reference values for preterm and term infants. Correlation of LW/BW with age-matched reference values at postmortem examination represents an invaluable additional tool to evaluate lung growth, particularly in preterm infants.

Body Weight↗

PubMed2005

Comparison between maximal early diastolic velocity in long-axis direction obtained by M-mode echocardiography and by tissue Doppler in the assessment of right ventricular diastolic function.

Recently the maximal early diastolic velocity in long-axis direction of the right ventricle (RV) obtained by tissue Doppler imaging (MDV TDI) has been introduced in the assessment of RV diastolic function (RVDF). There are reasons to think that also the maximal early diastolic velocity in long-axis direction of the RV obtained using M-mode echocardiography (MDV TAM) could be used to assess RVDF. Therefore, 29 patients were examined with echocardiography and MDV TAM and MDV TDI were measured and compared. A good correlation (r = 0.76, P < 0.001) was found between MDV TAM and MDV TDI indicating that MDV TAM might be used in the assessment of RVDF. However, the velocities obtained by MDV TDI (126.7 +/- 38.9 mm s(-1)) were significantly (P < 0.001) higher than the velocities obtained by MDV TAM (78.3 +/- 27.8 mm s(-1)) and the agreement between MDV TAM and MDV TDI was rather poor probably mainly due to differences in the measuring technique. This means that reference values cannot be used interchangeably between MDV TAM and MDV TDI. If MDV TAM is going to be used in the assessment of RVDF new reference values have to be produced if today's technique and recommendations to measure MDV TAM and MDV TDI are used. However, as most new echocardiographs are equipped with PW-TDI technology it seems preferable to use this technique and compare obtained values with already established reference values.

Diastole↗

PubMed2005

Effects of sex, age, body mass, and capturing method on hematologic values of brown bears in Croatia.

Effects of various intrinsic and extrinsic factors on 17 hematologic values from 56 brown bears (Ursus arctos) sampled in Croatia from 1981 to 2005 were evaluated. Differences between female and male bears were detected for number of erythrocytes, sedimentation rate after 30 min, and number of leukocytes and segmented neutrophils. Significant differences between free-living vs. captive and snared vs. not snared bears were detected for the same three parameters: leukocytes, segmented neutrophils, and eosinophils. It was concluded that the physical exertion of bears snared by leg, rather than their free-living status, influenced differences of results among these groups. The obtained mean values are useful reference values for the species.

Age Factors↗

PubMed2000

Comparison of absorptive capacities of original and modified Schirmer tear test strips in dogs.

OBJECTIVE: To compare in vitro and in vivo absorptive capacities of modified Schirmer tear test strips with those of original strips, and to establish reference values for use with the modified strips. DESIGN: Prospective study. ANIMALS: 100 dogs. PROCEDURE: In vitro absorptive capacity was determined by immersing strips in an irrigating solution for 15 seconds and recording amount of wetting. In vivo absorptive capacity was determined by placing an original Schirmer tear test strip in 1 eye and a modified strip in the other eye of 50 dogs with normal or abnormal tear production. Time required to wet 10 mm of each strip was recorded. Measurements were repeated 30 minutes later after reversing which strip was placed in the left or right eye. Reference values (mean +/- SD) were determined by recording the time required to wet 10 mm of the modified strip in 50 healthy dogs. RESULTS: Amount of wetting was significantly less and time required to wet 10 mm was significantly greater for the modified strip, compared with the original strip. Reference values determined for the modified strip were 32 +/- 11 seconds in the right eye, 33 +/- 11 seconds in the left eye, and 32 +/- 10 seconds in both eyes. CONCLUSIONS AND CLINICAL RELEVANCE: Absorptive capacities of the original and modified Schirmer tear test strips were significantly different. Reference values determined for 1 strip should not be used for the other strip.

Absorption↗

PubMed2002

Radiographic changes in the lumbar intervertebral discs and lumbar vertebrae with age.

STUDY DESIGN: Plain lateral radiographs of the lumbar spines of 607 women (age range 20-87 years) and 633 men (age range 20-92 years) were studied. OBJECTIVE: To study the radiographic changes in the lumbar intervertebral discs and lumbar vertebrae with age. To compile a database of reference values for the age-dependent height of lumbar discs and concavity index of lumbar vertebral bodies as well as prevalence of vertebral osteophytes by age and sex. SUMMARY OF BACKGROUND DATA: There is a general agreement that changes induced by aging lead to alterations in the thickness of the disc, but there are differences in the accounts of the effect of aging on the thickness of the lumbar discs. Published methods to measure disc height yield, except for some exceptional cases, inaccurate results. Reference values of disc height and concavity index of lumbar vertebral bodies, suitable for quantitative comparison with a given disc and lumbar vertebral body, have yet to be established. METHODS: Using a new protocol with a precision of 3.9%, the anulus heights of lumbar discs were measured from sets of lateral radiographic views of 607 women and 633 men. The measurement of concavity index of vertebrae was established for each vertebral body by dividing the central vertebral height by the anterior vertebral height. RESULTS: The heights of lumbar discs T12-L1, L1-L2, L2-L3, L3-L4, L4-L5, and L5-S1 of men and women within the age 20-69 years increased with increasing age (4.6-6.9% in men and 4.7-8.4% in women). The concavity index of vertebrae T12, L1, L2, L3, L4, and L5 of men within age 20-87 years and of women within age 20-92 years decreased linearly with increasing age (0.9-1.5% in men and 1.6-3.2% in women). In other words, the vertebral body endplates became more concave with age. The prevalence of osteophytes was greater in men than in women in lumbar spine and increased with age. CONCLUSIONS: Using the new procedure and the database of reference values, it is possible to measure the height of lumbar discs and concavity of vertebrae objectively and precisely and to compare the results quantitatively with reference values.

Adult↗

PubMed1994

Decline in sperm counts: an artefact of changed reference range of "normal"?

OBJECTIVE: To investigate a reported fall in sperm counts during 1940-90 in relation to the reduced lower reference value of "normal" during the same period by assuming the null hypothesis that no change had occurred in the probability distribution of the sperm concentration. DESIGN: Analysis by using various mathematical models of the probability distribution of sperm concentration together with experimental data which supported a model employing a logarithmic distribution. SUBJECTS: 235 men presenting for stimulated in vitro fertilisation at Midland Fertility Services, Aldridge, in 1992 together with samples of 20 ejaculates from each of five men attending the same centre during 1992-3. RESULTS: The effect of the change in lower reference value for the "normal" sperm concentration (from 60 x 10(9) to 20 x 10(9)/l) depended on the probability distribution of the concentration in the population. If that distribution was normal or uniform, then very little of the reported decline was a consequence of the change in lower reference value. If it was heavily skewed, then most or all of the reported decline may have been a consequence of that change. The limited experimental data available indicate that the distribution was heavily skewed. CONCLUSIONS: Depending on the actual distribution of sperm concentration in the population, the reported decline in concentration may have been accounted for entirely or in part by the change in lower reference value. The original evidence does not support the hypothesis that the sperm count declined significantly between 1940 and 1990.

Humans↗

PubMed1992

[Clinico-chemical blood parameters in foals in the first two months of life].

Eighteen healthy foals were studied from birth until 2 months of age. Blood samples were obtained at the following times: presuckle, 30 hours, 1, 3, 5, 7 and 9 weeks of age. Changes in serum P, Mg, Ca, Na, K, Cl, iron, AP, ASAT, ALAT, GGT, GLDH, CK, lipase, urea, creatinine, cholesterol, triglyceride, uric acid, protein and fibrinogen and in plasma total solids were examined and the values compared to reference values of adult horses. There were characteristic age related changes in several parameters. Single measurements should be interpreted cautiously to allow for individual variations.

Aging↗

PubMed1985

Trace elements in human body fluids and tissues.

Published figures for trace element concentrations in body fluids and tissues of apparently healthy subjects are widely divergent. For a considerable time, the apparent disparities were readily ascribed to biological sources of variation such as age, sex, dietary habits, physiological conditions, environmental exposure, geographical circumstances, or similar influences. Growing evidence, however, suggests that this interpretation may be seriously questioned in numerous instances. First, values obtained in reference materials leave no doubt that some previous studies must have been subject to gross analytical inaccuracies. Second, it has now been thoroughly documented that inadequate sample collection and manipulation may drastically distort the intrinsic trace element content of biological matrices. This review scrutinizes data reported by a number of investigators. In an effort to settle the currently flourishing confusion, critically selected reference values are set forth for trace element levels in human blood plasma or serum, packed blood cells, urine, lung, liver, kidney, and skeletal muscle tissue.

Aluminum↗

PubMed2000

A Procedure for Performing Population-Level Ecological Risk Assessments.

/ In 1997, Oregon enacted amendments to its state hazardous waste site cleanup law which emphasize risk-based remedial action decisions. In a departure from US EPA practice, the amended statute and associated rules require that protection of ecological receptors occur at the population level for all plants and animals not listed as threatened or endangered. By rule, the acceptable risklevel for populations of ecological receptors is a 10% or less chance that 20% or more of the total local population would receive an exposure greater than the toxicity reference value for a hazardous substance. This paper describes a practical procedure for performing population-level ecological risk assessments using a combination of relatively simple techniques. The procedure involves: (1) establishing a distribution of exposures and a contaminant-specific toxicity reference value, either as a point value or a distribution, for an individual receptor, (2) estimating the abundance of these receptors within their local populations, (3) estimating the probability of an individual receptor experiencing an exposure in excess of the toxicity reference value, (4) estimating the number of individual receptors in the local population likely to experience an exposure above the toxicity reference value greater than 10% of the time, and (5) determining whether this number is greater than 20% of the total local population.

Journal Article↗

PubMed2003

Continuous glucose monitoring: reliable measurements for up to 4 days with the SCGM1 system.

Continuous glucose monitoring allows patients with diabetes to check their metabolic status throughout the day, including rarely monitored time periods, such as postprandial and nocturnal periods. The performance of a prototype of the novel SCGM1 System (Roche Diagnostics GmbH, Mannheim, Germany) employing the microdialysis technique was evaluated. Forty-two patients with type 1 diabetes participated in the study [29 males/13 females, age 34 +/- 9 years, duration of diabetes 16 +/- 11 years, glycated hemoglobin 7.7 +/- 1.2% (mean +/- SD)]. Forty-seven experiments were performed at four different investigational sites. A microdialysis catheter was inserted into the subcutaneous tissue of the patient's abdominal wall. Glucose was extracted from the interstitial fluid, and glucose levels were determined and stored by the SCGM1 System continuously for the duration of the experiment. Capillary blood glucose was measured frequently (at least 10 times per day) and used for linear retrospective calibration. The patients were instructed to maintain their normal diet and insulin therapy. Thirty experiments (mean duration 103 +/- 18 h) were analyzed in detail. The mean deviation of the calibrated glucose sensor values from the capillary blood glucose values (expressed as percent predicted error sum of squares) was <12.5% in 25 and <20% for all of the 30 experiments analyzed. The percent median absolute difference between the calibrated values and the reference values was <10% in 28 experiments, with a median of 5.8% for all 30 experiments. The error grid analysis of all 30 experiments showed that 99.5% of all 1,195 pairs' values were in zones A and B with only 0.2% in zone C and 0.3% in zone D. Thus the microdialysis technique employed by the SCGM1 System allows precise and accurate continuous glucose monitoring over prolonged periods of time. It appears also that effective monitoring of acute metabolic deteriorations is possible.

Adult↗

PubMed2003

Continuous glucose monitoring with glucose sensors: calibration and assessment criteria.

Continuous glucose monitoring (CM) by means of minimally invasive or noninvasive glucose sensors can help to further optimize metabolic control in patients with diabetes without need for frequent capillary blood glucose measurements. Most glucose sensors measure glucose concentration in the interstitial fluid (ISF). Because of the varying conditions in this compartment, a general in vitro calibration ( = factory calibration) by the manufacturer appears not to be possible. Therefore, calibration of the sensor signal must be performed by the patient himself repeatedly. The calibration procedure can be performed by means of conventional capillary blood glucose measurements in order to transform the sensor signals obtained from the specific compartment (e.g., ISF) into "blood" glucose values. A number of aspects can influence the validity of this procedure. The relationship between changes in blood glucose and in ISF glucose, in both time and concentration dimensions, is not well understood, especially during dynamic changes. The physical lag time, which critically depends on the glucose sensor technology used, can also introduce a systematic calibration error. After the first calibration, usually performed some hours after the application of a given glucose sensor, recalibration at certain intervals is necessary. Therefore, patients should critically assess the values displayed by a CM system. In the case of implausible glucose values they should verify the results by means of a conventional capillary glucose measurement. Up to now there is no consensus on assessment criteria to be used for evaluation of CM system performance and calibration quality. Existing methods of displaying CM values against corresponding reference values, including linear regression analysis and error grid analysis, as well as numeric criteria such as System Error, Predicted Error Sum of Squares (in %), and Mean Absolute Deviation are not generally applicable to CM. It appears as if they do not allow sufficient description of data obtained with CM systems. There is a pressing need to develop novel adequate assessment criteria enabling a better characterization of CM system performance. If these were used uniformly by all manufacturers and scientists assessing CM systems, this would allow a fair comparison of the performance of different systems.

Blood Glucose↗

PubMed1998

[Measurement of glomerular filtration rate (GFR) after administration of iodine contrast medium with the Renalyzer PRX90 in healthy cats and cats with kidney diseases].

In the present study, the measurement of the glomerular filtration rate (GFR) in the cat with the aid of an iodine contrast medium clearance with the renalyzer PRX90 is introduced. Investigations on the accuracy of measurement showed that even repeated measurement of plasma samples after two days of storage at room temperature yielded reproducible clearance results. Also, partial dilution of the plasma sample (2 ml with 1 ml Aqua bidest.) to reduce the volume of blood withdrawn still produced reliable results. Further dilution of the plasma volume (1 ml with 2 ml Aqua bidest.) however did not allow for accurate measurements. A total of 59 cats of different age and sex were included in the study. 31 cats had healthy kidneys with urea and creatinine values within the reference range, unchanged urine findings and physiologic urine protein patterns (SDS-PAGE). These cats served as reference group. The GFR reference value ascertained for these animals was 2.1 ml/min/kg BW (mean = 3.45 ml/min/kg with s = +/- 1.0 ml/min/kg). 28 cats had elevated values of urea and creatinine in the blood, as well as partially changed urine findings. For further diagnosis of renal disease, separation of urine proteins was done with the SDS-PAGE in the PhastSystem, which in all cases yielded a pathologic urine protein pattern. In 11 cases the renal disease could be further confirmed by histological investigation. GFR in these patients was clearly lowered compared with healthy cats, with measured values between 0 and 1.8 ml/min/kg. It can be concluded that the renalyzer allows reliable determination of the GFR also in the cat. To what extent measurement of the GFR is also helpful to diagnose nephropathies in the stage of compensation needs to be further investigated. In cats with high grade uremia and a GFR below 1 ml/min however, an exact calculation is not possible, since the accuracy of measurement within this range is inadequate. Thus, in severe disease no correct assessment is possible, and no statement concerning prognosis can be made.

Animals↗

PubMed1997

Urinary phosphate/creatinine, calcium/creatinine, and magnesium/creatinine ratios in a healthy pediatric population.

OBJECTIVE: To determine reference values for urinary phosphate/creatinine (Cr) concentration ratios and to complete reference values for urinary calcium/creatinine and magnesium/creatinine ratios in the second morning urine sample of healthy infants, children, and adolescents. DESIGN: Urinary P/Cr, Ca/Cr, and Mg/Cr ratios were determined from the second morning urine sample. Two urine samples were obtained 1 week apart from most subjects to assess reproducibility. SETTING: Kindergartens and schools of Lausanne, Switzerland. PARTICIPANTS: A total of 410 healthy children aged 1 month to 17 years (197 girls and 213 boys) participated in the study. RESULTS: The 5th and 95th percentiles were estimated from 664 urine samples. There were no differences related to sex. A nonlinear regression in terms of age was used to smooth the estimated percentiles yielding reference curves from which critical values may be obtained for any given age. The 95th percentile for urinary Ca/Cr and Mg/Cr agreed with previously reported values in children older than 7 years. The upper limit of the three solute/creatinine ratios decreased significantly with age: for urinary P/Cr from 19.0 mol/mol at 1 month to 2.7 at 14 years; for urinary Ca/Cr from 2.2 to 0.7 mol/mol, and for urinary Mg/Cr from 2.2 to 0.6 mol/mol. Lower limits varied little. Interindividual and intraindividual variations decreased with age. CONCLUSIONS: Urinary P/Cr, Ca/Cr, and Mg/Cr ratios vary strongly with age. We provide reference values, expressed both in SI and in mass units, for urinary P/Cr, Ca/Cr, and Mg/Cr in children aged one month to 17 years.

Adolescent↗