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At least 1,783 records · Page 99Linked to original sources
PubMed2006

Ten-year trends in obesity among Israeli schoolchildren: 1990-2000.

AIM: To analyze trends in childhood body mass index (BMI) in Israel between 1990 and 2000, and to determine the proportion of obese children using US and population-specific reference values. METHODS: Cross-sectional data from 13 284 second- and fifth-grade schoolchildren were collected, including age, sex, height, weight, country of birth, and time since immigration. Age- and sex-specific BMI means and centiles were calculated, and the prevalence of obesity was determined using Israeli and US reference values. RESULTS: BMI values at the 95th centile increased monotonously over time in all age and sex categories. Between 1990 and 2000, 95th centile values increased by 12.7% and 11.8% among second-grade boys and girls, respectively. Among fifth-grade children, 95th centile values increased by 10.2% and 8.4%, respectively. Among second graders in 2000, 11.4% of both boys and girls exceeded the BMI value recorded at the 95th centile in 1990. Among fifth-graders in 2000, 10.7% of boys and 11.1% of girls exceeded the 1990 BMI reference value (p for all comparisons < 0.001). The proportion of obese children increased over time using both Israeli and US reference values. CONCLUSION: This substantial increase in childhood obesity poses a serious health threat, and requires implementation of suitable public health interventions.

Age Distribution↗
PubMed1996

Magnesium fractions in serum of healthy individuals and CAPD patients, measured by an ion-selective electrode and ultrafiltration.

OBJECTIVES: Validation and comparison of a magnesium ion-selective electrode (ISE) with a cation-exchange resin technique, followed by determination of all magnesium fractions in serum of healthy volunteers and continuous ambulatory peritoneal dialysis (CAPD) patients. DESIGN AND METHODS: The analytical aspect has been studied by measuring the influence of complexing agents on the fraction ionized magnesium (friMg2+). A theoretical approximation of friMg2+, based on mass equilibria and complexation constants, was calculated and compared with the measurements. RESULTS: ISE measurements showed good agreement with theory. Reference values of the ionized, protein-bound, and complexed magnesium fractions were (mean +/- SD) 0.65 +/- 0.04, 0.27 +/- 0.04, and 0.08 +/- 0.03, respectively. Fractions obtained in the CAPD group were 0.62 +/- 0.04, 0.22 +/- 0.05, and 0.16 +/- 0.05, respectively, and differed significantly from the values of the reference population. CONCLUSIONS: All known serum magnesium parameters can be established by a combination of ultrafiltration, atomic absorption spectrometry, and ISE measurements. Unknown complexing compounds most probably account for the increased fraction of complexed magnesium in the serum of CAPD patients.

Adult↗
PubMed1989

Whole-blood lymphocyte cultures.

A simple and reproducible method is described for the measurement of proliferative responses of peripheral blood lymphocytes in whole blood upon stimulation with horse anti-human lymphocyte serum (ALS), phytohaemagglutinin (PHA) or a monoclonal antibody (mAb) directed against CD3. Only small aliquots of blood are needed and separation procedures are not necessary. Since the method proved to be very reproducible and showed little variation, reference values of proliferation, expressed in cpm per 15 microliters blood and cpm per 10(3) CD3+ lymphocytes, were determined based upon the 5th and the 2.5th percentile of the distribution of the values in our reference population. In addition, the use of whole blood lymphocyte cultures in longitudinal studies of immunocompromised individuals is demonstrated.

Adolescent↗
PubMed2004

[New common reference intervals for clinical chemistry in the Nordic countries. A better basis for clinical assessment and cooperation].

A project engaging the five Nordic countries has presented common reference intervals for the most frequently used biochemical and haematological analytes. The results are based on samples from up to 3000 healthy adult reference persons and are statistically calculated to include 95% of the reference population's values. Reference samples were analyzed together with commutable control materials traceable to reference methods (IMEP-17). Enzymes were analyzed using methods traceable to IFCC reference methods. The Swedish Society of Clinical Chemistry now recommends its member laboratories to introduce the new reference intervals and new enzyme methods during 2004.

Adult↗
PubMed1991

Measurement of alkaline phosphatase activity in serum with N-methyl-D-glucamine as a buffer: evaluation of the method for routine use.

Some aspects of the measurement of alkaline phosphatase activity concentration in human serum, using N-methyl-D-glucamine as a buffer, were evaluated with a view to the possible routine use of the method. The evaluated characteristics included: the temperature-dependence of the pH of the buffer; the effect of adding the magnesium/zinc ions buffer; the effect of the serum volume fraction; the substrate-starter versus the serum-starter mode; the effect of modifying the formulation of reagents; the within-run and the between laboratory imprecision; the correlation with an alternative routine method. Also, sex- and age-related reference values were produced, based on 2968 values from selected reference sample groups in 7 laboratories. In general, the results demonstrate the robustness of the method, its adaptability to a variety of mechanized analysers, and hence its feasibility as a routine measurement method.

Adolescent↗
PubMedDate not supplied

[Reference population values for the Spanish Child Health and Illness Profile-Adolescent Edition (CHIP-AE) using a representative school-based sample].

AIM: The Child Health and Illness Profile (CHIP-AE) is a generic health status instrument for adolescents aged 12-19 years adapted for use in Spain. The aim of this study was to obtain reference population values of the Spanish version of the CHIP-AE. METHODS: The CHIP-AE was administered to a representative sample of adolescents from schools in Barcelona. The sample was selected by using cluster-sampling, stratified by type of school (public or private) and an ecological socioeconomic index (Indice de Capacidad Familiar: low, middle, and high). The CHIP-AE scores were standardized to a mean of 20 and a standard deviation (SD) of 5. Means and percentiles were computed. Means were compared by age, gender, and socioeconomic status using analysis of variance. RESULTS: The response rate was 81% (n = 902). The distribution of the CHIP-AE scores presented a wide range with scores generally skewed toward positive health status. Nevertheless, the results suggest that the sample selected from a general population was not free of health problems. Twenty-five percent of adolescents presented scores below 17.2 in the domain of discomfort, indicating an effect size of 0.56 standardized SD units. The distribution of scores in the reference samples from Barcelona was similar to the original results in Baltimore (USA), with some marginal differences in individual risks. CONCLUSIONS: The CHIP-AE systematically gathers information on health domains in adolescents. The results from this reference sample will allow comparisons with adolescents from other regions, and/or with different health problems, as well as description of inequalities in health during adolescence.

Adolescent↗
PubMed2005

High resolution electrocardiography in healthy dogs: time domain parameters and comparison of the non-stationary (Wigner distribution) versus standard stationary frequency domain analysis methods.

Fractionated heart activation can be detected as late potentials from surface recordings of signal-averaged electrocardiograms (SA ECG) which are considered as a marker of sustained ventricular tachycardia. For animal studies, reference values in time and frequency domain analyses are essentially missing. In the present study, we have established reference values in SA ECG time domain analysis and time-frequency representation of heart activation in healthy dogs. A group of 25 healthy mongrel dogs (body weight 12-15 kg) was investigated. Wigner distribution and our modification of Fast Fourier transform (FFT), gliding window FFT, was applied in SA ECG frequency domain analysis. Reference values in time domain SA ECG were established. Time and voltage criteria were adapted to short duration of heart cycle and fast voltage decrement of the QRS complex in dogs. Wigner distribution and gliding window FFT were applied in order to describe mean heart activation in the frequency domain. Contribution of higher frequencies (30-80 Hz) was detected by both frequency analysis methods in the second third of ventricular activation in healthy animals. Presented results could offer a basis for further experimental arrhythmologic studies.

Algorithms↗
PubMedDate not supplied

Age-related changes in laboratory test results. Clinical implications.

Many quantities assayed in clinical laboratories demonstrate age-related changes. Particularly important periods are early life, adolescence, old age, and after the menopause in females. The changes that occur until adulthood are well documented. Fewer data are available on elderly people even though they consume a large component of healthcare resources. In diagnosis, and prior to initiation of drug therapy, when no previous results are available, reference values must be available to aid interpretation. Reference intervals generated from elderly people are sometimes wider than in younger adults. It is suggested that conventional adult reference values should be used in general for the very elderly since, at least in part, the wider intervals are probably due to inclusion of individuals who are unhealthy in the reference sample group. Most quantities have marked individuality, and serial values for an individual span only a part of the reference interval. Individuals can have values which are very unusual for them but still lie within the reference limits; this implies that clinical laboratory tests will be less than ideal in the detection of latent or early disease. The average within-subject variation in healthy elderly people and younger adults is similar. Therefore, the large database on biological variation can be used, with analytical imprecision, to calculate critical differences for serial results in an elderly individual which must be exceeded before significance can be claimed. These critical differences are of value in monitoring the effects of drug therapy.

Aged↗
PubMed2002

Developments in the RICE asbestos fibre counting scheme, 1992-2000. Regular Interlaboratory Counting Exchanges.

The UK's Regular Interlaboratory Counting Exchanges (RICE) scheme provides proficiency testing for laboratories counting asbestos fibres by phase contrast optical microscopy, as in the method for measurement of airborne fibre concentrations. From 1984 to 1992, the scheme used circulations of industrial samples containing mostly chrysotile, and reference values were obtained from fibre counts by automated image analysis. In 1992, lower density (< 100 fibres/mm2) samples from asbestos clearance operations were added and the new reference values were medians of the laboratories' determinations. In extensive data from 28 recent rounds of sample exchanges, the new reference values are shown to be more reliable than the old. Average counting levels have changed, with different trends according to fibre density. In low density samples, after initial increases, the levels appear to have stabilized. Counting levels on the higher density samples show a continuing trend of approximately 0.5% decrease per round. Widening the density range may have reduced the influence of counters' preconceptions of what values are expected and so their counts on the reference samples may now better reflect their routine counting. The implications of these findings and of other new developments, such as expected new counting rules, are discussed.

Asbestos↗
PubMed2006

Biological variation, individuality and critical differences of eight biochemical blood constituents in budgerigars (Melopsittacus undulatus).

The aim of the study was to obtain basic data on individual biological variation, the required number of specimens to define the homeostatic setpoint (the aspired value of a variable adjusted to the individuals homeostasis) and critical differences of selected chemistry parameters in budgerigars (Melopsittacus undulatus). Blood from 99 healthy budgerigars was sampled 12 times at four-week intervals. Aspartate aminotransferase (ast), calcium, creatine kinase (ck), glutamate dehydrogenase (gldh), glucose, lactate dehydrogenase (ldh), total protein and uric acid were investigated. The indices of individuality obtained in the present study were relatively low (total protein 0.93, ast 1.02, gldh 1.04, ck 1.12, ldh 1.24, uric acid 1.26, glucose 1.39, calcium 1.61) and suggest that population-based reference limits might be useful. Comparison of data showed that the application of intraindividual reference values identified much greater variation in the reference values than using conventional population-based reference limits. Otherwise, the moderate to low degrees of individuality may allow the use of reference values of one individual as a standard for another individual of the same species. The critical differences that define the change needed between two serial results to indicate a biological change was highest in gldh with 120 per cent or 1.7 U/l. In calcium, a change of 30.5 per cent or 0.5 mmol/l would be significant. In the other parameters critical differences varied between 38 per cent in glucose, up to 93 per cent in uric acid.

Animals↗
PubMed1998

Quantitative digital evaluation of myocardial exercise thallium-201 single-photon emission tomography in post-menopausal women.

Quantitative computerized analysis of data from myocardial thallium-201 (201Tl) single-photon emission tomography (SPET) may improve the diagnostic accuracy of coronary heart disease. The reference ranges for post-menopausal women are, however, limited and obtained mainly from patients. To compare reference values from healthy post-menopausal women and to improve the quantitative analysis, 20 women (10 patients with coronary heart disease and previous infarction and 10 age-matched healthy volunteers) were examined immediately post exercise and after a delay. A nine-segment 'bull's-eye' model was used for analysis. At visual evaluation, reproducibility was high (93%), no false-positive results were obtained and in 70% of the patients the SPET was interpreted as abnormal. Using reported reference values for quantitative analysis, all the healthy women had an abnormal result. New reference values based on three different methods of 'normalization' were calculated: the relative activity of segment 3 set to 100%, the segment with the highest activity set to 100% and a least-squares method. They all differed significantly from those that had previously been reported. The frequencies of agreement between visual and quantitative analysis were 84-92% and were highest when segment 3 was used as a reference, but in this case only 40% of the patients with coronary heart disease had an abnormal SPET. Using the least-squares method for handling digital information, the SD of the normal values decreased and 90% of the patients with coronary heart disease were accurately diagnosed. These results provide quantitative digital reference values for healthy post-menopausal women. They verify that quantitative analysis is in diagnostic agreement with visual evaluation, stress the need for local verification of reference ranges and suggest a least-square normalization method for the analysis.

Aged↗
PubMed2004

[Evaluation of renal damage using urinary ATP analysis].

It is reported that urinary ATP concentration analysis is useful for determining urinary tract infection and renal damage caused by drugs. By means of the firefly luciferin-luciferase method, we determined the reference value of urinary free ATP and evaluated the effects of urine sediments and conditions of storage. The reference value was established as 1.77 x 10(-10) to approximately 7.70 x 10(-9)M using urine samples obtained from 63 outpatients who seemed to have no renal disease. There was no significant difference in ATP concentration between 33 males and 30 females. No significant changes were observed in 11 healthy volunteers during a 1-year period. Within-run reproducibility of ATP was satisfying (8.28% and 11.4% of coefficient value in low and high concentration samples, respectively). ATP concentration was significantly decreased after centrifugation (p < 0.05) and after filtration (p < 0.01). The amounts of the red blood cells (RBC) and white blood cells (WBC) in samples whose ATP concentration was decreased after centrifugation or filtration were significantly higher than those in samples whose concentration did not decrease (p < 0.05). Urine containing many RBCs and/or WBCs might show an artificially higher ATP concentration if no preparations has been performed. There were significant positive correlations between the ATP concentrations before and after refrigeration, but no correlations before and after freezing. It is concluded that the reference value of urinary free ATP concentration was 1.77 x 10(-10) to approximately 7.70 x 10(-9) M and that care is required in the estimation of urinary ATP concentrations in samples containing many sediments, especially with WBC and RBC.

Adenosine Triphosphate↗
PubMed1993

Lipid peroxidation and trace element status in diabetic ketotic patients: influence of insulin therapy.

Lipid peroxidation is known to accelerate aging and microvascular lesions in diabetic patients. We studied the acute influence of improved glycemic control on the concentrations of plasma lipid peroxidation intermediates [malondialdehydes (MDA), organic hydroperoxides (OHP)] in ketotic insulin-dependent diabetic patients, as well as the interplay of enzymes such as glutathione peroxidase (GPX) and CuZn superoxide dismutase (CuZn-SOD), and trace elements (Zn, Se, Cu) postulated to be involved in free radical protection. These plasma components were measured on the first day of hospitalization (T0) and when the patient had attained a stable glycemic state after continuous insulin treatment (T1). Plasma MDA and OHP concentrations were high at the beginning of the study but approached reference values after glycemic equilibration. Plasma zinc concentrations were significantly (P < 0.05) decreased during the ketotic state, but also approached reference values with glycemic equilibration. Plasma selenium concentrations and GPX activity were relatively unchanged between T0 and T1. Erythrocyte GPX activity measured at T1 in six patients was below the reference values, whereas CuZn-SOD activity was not affected. Our results show that enhanced lipid peroxidation is associated with decreased zinc plasma concentrations in ketotic patients and underline the beneficial effects of continuous insulin infusion. The mechanisms involved are still unclear but may indicate the importance of extracellular zinc transfer secondary to glycemic disorders.

Adult↗
PubMed2000

[Changes in bone mineral density in Th12 to L5 vertebrae in female patients with osteoporosis].

UNLABELLED: The authors examined 47 female patients, age 50-60 years, with primary and secondary osteopenia and osteoporosis. In each patients they assessed the bone mineral density (BMD) of the cortical and trabecular bone of vertebrae Th12 to L5 by quantitative computer tonmography (QTC). They did not include in the group patients with deformities of the vertebrae grade one, two and three. These deformities were assessed from a lateral X-ray of the thoracic and lumbar spine. OBJECTIVE: To evaluate the importance of assessed BMD values of vertebrae from the biomechanical aspect. STATISTICAL ANALYSIS: Individual groups of assessment of BMD in cortical and trabecular bone for each vertebra were characterized by means of 95% confidence intervals and their means or median values. RESULTS: The BMD of cortical bone increases from Th12 to L5 almost in a linear fashion. BMD of the trabecular bone declines from Th12 to L3, in L4 abd L5 it rises again. The lowest values were recorded in L3. The greatest decline of BMD of the trabecular bone by 24.05% in L3 as compared with reference values of the given age groups were not conditioned by deformities of the vertebrae. The BMD of cortical bone in osteopenic and osteoporotic patients practically did not differ from reference values for the given age group. CONCLUSION: From the presented work ensues that deformities of the vertebrae do not occur as long as the BMD of cortical bone is within the range of reference values despite a decline of BMD in trabecular bone. It is thus more important to investigate the material qualities of cortical bone because the risk of fractures of the vertebrae depends on the elasticity and firmness. Critical BMD values of cortical bone assessed by QCT for the development of fractures are not known so far. QTC of vertebrae due to its higher radiation load and financial costs is not a routine densitometric method. It will be necessary to develop new densitometric methods which will make it possible to assess BMD or another property of cortical bone and assess critical values for the development of vertebral fractures.

Absorptiometry, Photon↗
PubMed1999

Electrically elicited blink reflex in horses with trigeminal and facial nerve blocks.

OBJECTIVE: To reassess reference values for the components of the electrically induced blink reflex, document reference values for facial motor nerve conduction velocity, and demonstrate usefulness of the blink reflex as a diagnostic tool in peripheral facial and trigeminal nerve dysfunction in horses. ANIMALS: 10 healthy adult horses (8 males, 2 females) without neurologic abnormalities. PROCEDURE: Blink reflex tests were performed by electrical stimulation of the supraorbital nerve and facial (auriculopalpebral) nerve. Reflex and direct muscle-evoked potentials of the orbicularis oculi muscles were recorded from concentric needle electrodes inserted bilaterally in these muscles. Supraorbital and auriculopalpebral nerve blocks were performed by lidocaine hydrochloride injections. RESULTS: Supraorbital nerve stimulation elicited 2 or 3 ipsilateral and 1 contralateral reflex muscle potential in the orbicularis oculi muscles. Auriculopalpebral nerve stimulation elicited a direct and a reflex potential in the ipsilateral orbicularis oculi muscle. After left supraorbital nerve block, no responses could be elicited ipsilaterally or contralaterally upon stimulation of the blocked nerve, but bilateral responses were obtained upon stimulation of the right supraorbital nerve. After right auriculopalpebral nerve block, no responses were recorded from the right orbicularis oculi muscle upon stimulation of left or right supraorbital nerves. CONCLUSIONS AND CLINICAL RELEVANCE: Reference values for the components of the blink reflex and facial motor nerve conduction velocity will allow application of these tests to assist in the diagnosis of equine neurologic disorders involving the trigeminal and facial nerves, the brainstem, and the cranial end of the cervical segment of the spinal cord. This study reveals the usefulness of the blink reflex test in the diagnosis of peripheral trigeminal and facial nerve dysfunction in horses.

Animals↗
PubMed2003

[The interpretation of the thyroid stimulating hormone (TSH) assay].

Current immunometric TSH assays guarantee a functional sensitivity of at least 0.10 mU/l. The 95% confidence interval of TSH reference values is 0.45-4.12 mU/l; it becomes slightly broader above the age of 60 years (0.4-5.9 mU/l for 70-79 years). Interference by heterophilic antibodies in the TSH assay may give rise to spuriously elevated TSH values. The TSH assay is a very accurate diagnostic test for screening thyroid function. A normal TSH indicates euthyroidism with an accuracy of > 99%; only the rare patient with central hypothyroidism may be overlooked, but the history usually provides sufficient clues to suspect hypothalamic or pituitary disease. In case of an abnormal TSH value, a FT4 assay should be done. Each of the six possible outcomes (decreased or increased TSH combined with a decreased, normal or increased FT4 value) points to a specific diagnosis with an accuracy of over 90%. In the follow-up of treatment of thyroid function disorders, TSH target values are slightly different from the normal reference values. In primary hypothyroidism one aims at TSH values between 0.25 and 2.0 mU/l, but should avoid TSH values < or = 0.10 mU/l. In differentiated thyroid cancer, following complete thyroid ablation the target value is < or = 0.10 mU/l. A decreased TSH value in the course of treatment for Graves' hyperthyroidism does not necessarily indicate thyrotoxicosis, but may reflect persisting levels of TSH receptor stimulating antibodies.

Age Factors↗
PubMed2006

Assessing water clarity as a component of water quality in Gulf of Mexico estuaries.

The U.S. Environmental Protection Agency Environmental Monitoring and Assessment Program (EMAP) uses water clarity as a water quality indicator for integrated assessments of coastal waters. After the publication of the first National Coastal Condition Report (USEPA, 2001c), the national water clarity reference value of 10% of ambient surface light at 1 m depth was reevaluated and modified to reflect expected differences in regional reference light conditions. These regional differences range from naturally turbid estuaries like those found in Mississippi and Louisiana to clear water estuaries expected to support extensive beds of submerged aquatic vegetation in, e.g., Florida and Tampa Bays. For the second National Coastal Condition Report, water clarity was assessed based on regional reference values (USEPA, 2004). Different regional water clarity reference values and data collection methods necessitated the development of a water clarity index based on light attenuation coefficients (k). This index incorporates regional reference conditions and is interchangeable with secchi depth and percent light transmission calculated from light meter measurements. Evaluation of the water clarity index shows that k values based on transmissivity at 1 m can be estimated from secchi depth measurements and successfully used as a surrogate for transmissivity calculated from light meter data. An approach for assessing water clarity in Gulf of Mexico estuaries using light meter data and secchi depth is presented.

Atlantic Ocean↗