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PubMed2003

Effect of obesity and/or sleep apnea on chemosensitivity: differences between men and women.

The purpose of this study was to identify if obesity or obstructive sleep apnea (OSA) influence hypercapnic response (HCR) and hypoxic response (HR) taking into account differences between gender. Data are expressed in % predicted based on reference values of our laboratory ('Respir. Physiol. 113 (1998) 157'). Obese women without OSA (n=117, body mass index (BMI) 43+/-8 kg/m(2)) demonstrated an increased ventilatory (VE) and occlusion pressure (P(0.1)) HCR and HR slope: VE HCR 113 (NS), VE HCR/vital capacity (VC) 126 (P<0.05), P(0.1) HCR 130 (P<0.05), VE HR 136 (P<0.05), VE HR/VC 154 (P<0.001) and P(0.1) HR 210 (P<0.001) % predicted. Obese women with OSA (n=34, BMI 42+/-9 kg/m(2)) presented similar increased values for HCR and even more increased values for HR than obese women without OSA matched for age, height and BMI: VE HR 155 (P=NS), VE HR/VC 205 (P<0.05) and P(0.1) HR 273 (P<0.05) % predicted. In obese men (without or with OSA) HCR and HR values were similar to our reference values.

Adolescent↗

PubMed1970

Value of reference tracings in diagnosis and assessment of constrictive epi- and pericarditis.

Reference tracings are of great value in the diagnosis and assessment of constrictive pericarditis. The Q-h interval in the jugular venous pulse tracing is strongly correlated with the mean right atrial pressure (r=0.91). The left ventricular ejection time, the Q-A2 interval, and the Q-h interval are independent during atrial fibrillation from the preceding diastolic filling interval. This differentiates constrictive pericarditis from valvular heart disease. Cases with haemodynamically significant constrictive epicarditis are characterized by a rapid evolution, absence of pericardial calcification and absence of an early diastolic filling sound, a dominant a wave in the jugular venous pulse tracing, and a high early diastolic ventricular pressure. The haemodynamic behaviour is similar to that found in cases with myocardial fibrosis.

Adolescent↗

PubMed1987

[Use of the computer in the study of relations of indicators in the metabolic profiles of dairy cows].

Fifty dairy cows with metabolic alkalosis and forty-eight dairy cows of a control group were subjected to a metabolic profile test with 30 parameters. The results of analyses were confronted with reference values in histograms. We calculated mutual correlation coefficients for all parameters of dairy cows of the two groups. The correlations between selected pairs of parameters were represented diagrammatically in a form of correlograms. We demonstrated that the values of certain parameters being approximately identical, the correlations in group A of dairy cows (with alkalosis) varied in a different way from the correlations of the control group. It is seen from the results that the confrontation of the values of a parameter with reference values need not be in all cases a reliable criterion of evaluating the internal environment in dairy cows. We processed the metabolic profiles of the two groups by a multidimensional analysis of principal components. The dairy cows of the two groups clearly differentiated from one another according to the internal environment regarding the used parameters. We draw attention to a possibility of computerizing the diagnostic significance of the metabolic profile parameters.

Alkalosis↗

PubMed1996

Reference spirometric values in healthy Nicaraguan male workers.

The main objective was to derive reference equations for the FVC, FEV1, and FEV1/FVC ratio for healthy Nicaraguan male workers without current occupational exposure to agents hazardous to the lungs. Age, height, and weight were included as independent variables in the analysis, but only age and height showed significant effects on the indices studied. A nonlinear relationship with age was observed for FVC and FEV1, with a shift in the slope at the age of 32 years. Linear, quadratic, and multiphase models were tested in order to assess the best reference equation. The multi-phase model most closely fitted the values measured. The FEV1/FVC ratio showed a significant linear negative correlation with age. A comparison between the equations derived from this material and those reported in other studies revealed substantial differences. Racial, genetic, nutritional, work and sociocultural factors could account for the differences.

Adolescent↗

PubMed1999

Acoustical recognition of laryngeal pathology: a comparison of two strategies based on sets of features.

The efficiency of sets of acoustical features discriminating pathological voices from control voices is reported. Two strategies were compared. The first (called the 'distance strategy') was built upon a statistical distance of voice features to reference values obtained for a set of healthy (reference) voices. The second strategy (called the 'range strategy') is based on the position inside or outside normal ranges established from a reference population; results based on this strategy were presented in a previous paper. Reference values were calculated from a database of 200 healthy voices distributed into 10-year age groups ranging from 20 to 70. Comparisons were made using a second database of 220 voices, including 65 control, 51 functional dysphonia, 50 with nodules on the vocal folds and 54 recurrent nerve palsy. The phonetic material was compared of 17 French vowels: 11 vowels in a sentence, three isolated vowels and three segments (beginning, middle and end) of the sustained vowel /a/. Four acoustical features were considered for each vowel: the voice fundamental (f0) and the first three formant frequencies. Acoustical features were calculated on an ILS (Interactive Laboratory System) analysis system (workstation). The separation of each pathological group from the control group, using sets of acoustical features, was statistically assessed. From the strategy point of view, results indicated that (i) the fundamental frequency f0 was the best measure to separate normal from pathological voices with the distance strategy; (ii) when the formants were taken, the range strategy performed better in separating the voices. For classification of pathologies, the best separation coefficients were obtained with nodules and the worst with recurrent nerve palsy. Overall, it was seen that the separation between control and pathological voices was most efficient when measured using the distance strategy for f0. The range strategy was useful with formant frequencies.

Female↗

PubMed1999

Newer portable glucose meters--analytical improvement compared with previous generation devices?

BACKGROUND: Newer glucose meters are easier to use, but direct comparisons with older instruments are lacking. We wished to compare analytical performances of four new and four previous generation meters. METHODS: On average, 248 glucose measurements were performed with two of each brand of meter on capillary blood samples from diabetic patients attending our outpatient clinic. Two to three different lots of strips were used. All measurements were performed by one experienced technician, using blood from the same sample for the meters and the comparison method (Beckman Analyzer 2). Results were evaluated by analysis of clinical relevance using the percentage of values within a maximum deviation of 5% from the reference value, by the method of residuals, by error grid analysis, and by the CVs for measurements in series. RESULTS: Altogether, 1987 blood glucose values were obtained with meters compared with the reference values. By error grid analysis, the newer devices gave more accurate results without significant differences within the group (zone A, 98-98.5%). Except for the One Touch II (zone A, 98.5%), the other older devices were less exact (zone A, 87-92.5%), which was also true for all other evaluation procedures. CONCLUSIONS: New generation blood glucose meters are not only smaller and more aesthetically appealing but are more accurate compared with previous generation devices except the One Touch II. The performance of the newer meters improved but did not meet the goals of the latest American Diabetes Association recommendations in the hands of an experienced operator.

Ambulatory Care↗

PubMed2002

Guide for the practical application of the ICRP Human Respiratory Tract Model. A report of ICRP supporting guidance 3: approved by ICRP committee 2 in October 2000.

The ICRP Publication 66 Human Respiratory Tract Model for Radiological Protection (HRTM) has been applied to calculate dose coefficients (doses per unit intake) and bioassay functions in ICRP Publications 68, 71, 72 and 78. For these purposes, ICRP assigned numerical values to a range of model parameters, such as the size of the inhaled particles and the breathing rate of the subjects. These are known as 'default' or 'reference' values, and were chosen to be typical, representative values. In any particular situation the actual values of many parameters can be considerably different from the reference values. Usually, doses from intakes of radionuclides are low compared with the relevant limit or constraint, and the resulting difference is unimportant. There are, however, circumstances where more reliable assessments of intake and dose are desirable. This Guidance Document therefore gives advice on applying specific information within the framework of the HRTM for assessing occupational and environmental exposures and for interpreting bioassay data. Chapters on each aspect of the model (morphometry, physiology, deposition, clearance, gases and vapours, dosimetry) provide: A summary of how the HRTM treats that topic;Information on the reference values of relevant parameters;Guidance on choosing between default values;Information on how doses and bioassay quantities (lung retention, urine, and faecal excretion) vary with the values of selected parameters, giving guidance on the importance of obtaining specific information;Simple examples of the use of specific information relating to the topic.Annexes give additional information for those directly involved in applying the HRTM to specific situations, including guidance on obtaining parameter values. A brief overview is given of the deposition, characterisation, and sampling of aerosols, with references to further information, as there are relevant text books already available. Issues specific to radioactive aerosols, such as low particle number concentrations for high specific activity materials are, however, addressed. Guidance on obtaining information about absorption of inhaled radionuclides into blood is given in greater detail, because this is a topic on which ICRP has traditionally given guidance, and because a compilation of such information is not readily available elsewhere. Several detailed examples are also provided. One involves assessment of an individual's intake and committed dose from comprehensive bioassay monitoring data. The others deal with the derivation of HRTM absorption parameter values from experimental data, and their application, with additional information on e.g. size distribution, to calculate dose coefficients and interpret bioassay data.

Adolescent↗

PubMed1996

[Practical subjects of reference interval].

A concept of reference interval was first proposed by Dybkaer in 1973 in order to avoid an ambiguous definition of so-called normal range. This concept was succeeded by IFCC Expert Panel on Theory of Reference Value and the recommendation for the concept of reference value was documented in 1987 from IFCC scientific committee. Finally, NCCLS proposed the document for Reference Interval, how to determine, utilize the reference interval in clinical laboratory, in 1992. In this paper, how to determine and utilize the reference interval in clinical laboratory are described and discussed based on the concepts of NCCLS and IFCC.

Humans↗

PubMed1990

The necessity of achieving good laboratory performance.

The results of clinical biochemistry tests are used in the diagnosis of diabetes mellitus by comparing them with reference values or agreed international criteria. Low analytical imprecision is required so that reference values are not unduly widened by analytical variability. Most laboratory test results are used in monitoring. Low analytical imprecision is required so that changes seen in sequential results reflect stability, amelioration or deterioration, not simply analytical variability. Analytical bias should be absent so that results are (1) comparable in individuals over time as methods evolve and instrumentation changes, (2) equivalent over locale since tests may be done in practitioners' surgeries, outpatient clinics, and laboratories, and (3) able to be interpreted against the fixed criteria. A plethora of strategies have been proposed to set numerical desirable standards of performance, these being termed analytical goals, including use of reference values, opinions of clinicians, state of the art, the views of experts, and data on biological variation. Use of data on within-subject biological variation is currently considered the best approach. A generally applicable goal is that the total error should be less than one-half of the within-subject biological variation. Achievement of this adds about 10% through analytical variability to the true test variability. Analytical goals (CV, %) for glucose, fructosamine, urinary albumin, and haemoglobin A1 assays are 2.2, 2.1, 18, and 3.3%, respectively. These goals are targets worthy of attainment, not inflexible criteria of acceptance or rejection of methods.

Albuminuria↗

PubMed2005

Evaluation of two personal dosemeters in polyenergetic mono- and multi-directional neutron fields.

The neutron dose-equivalent response of two commercially available electronic personal neutron dosemeters was studied in several laboratory-produced broad-spectrum neutron fields. Fluence-weighted mean energies ranged from 200 keV to 4 MeV; personal dose-equivalent rates ranged from 75 to 10 mSv h(-1); and angles of incidence were multidirectional, 0 degrees, 30 degrees and 60 degrees. Three of these fields have been shown previously to resemble ones found in CANDU (Canadian Deuterium Uranium is a registered trademark of the Atomic Energy of Canada Limited) power plant workplaces. Both dosemeters were found to perform reasonably well across the range of energy spectra and angles of incidence. One type of dosemeter displayed values of the personal dose equivalent that were, at worst, within a factor of approximately 2 of the reference values and, at best, within a few per cent of the reference values. The other type displayed values of the personal dose equivalent that were consistently within unity and 20% of the reference values. Although the radiological performance of one was found to be more accurate, this device was also found to be the less rugged of the two. Some of the data acquired in this work were compared with results previously published by others. There was consistency between these sets of data.

Humans↗

PubMed2003

Age-specific analysis of normal cytokine levels in healthy infants.

While pathophysiology of elevated cytokines is well delineated, reference values for children are unknown, although they may vary physiologically with age and differ from those of adults. Between June and November 2001, interleukin (IL)-6, IL-10 and tumor necrosis factor-alpha (TNF-alpha) concentrations from blood samples of 79 healthy children in six different age groups (group I: 0-3 months; group II: 4-12 months; group III: 13-24 months; group IV: 25-36 months; group V: 37-48 months; group VI: 49-60 months) were measured with ELISA. TNF-alpha was within 2.2-3.5 pg/ml in all groups with a trend toward higher values in groups II and III (p = ns). IL-6 was significantly lower in group III than in groups IV (p = 0.0165) and VI (p = 0.0147). IL-10 was within 3.3-5.5 pg/ml in all groups (p = ns). In regression analysis no correlation between age and cytokine concentrations was found. Although not statistically significant, IL-6 was lower and TNF-alpha higher than the adult reference values provided by the kit manufacturer. Although reference cytokine levels seem not age-related during early infancy, IL-6 is significantly lower during the second year of life than later. In infants aged 5 years or younger, reference levels of IL-6 should be chosen lower, and those of TNF-alpha higher, than the adult reference values.

Adult↗

PubMedDate not supplied

Changes of albumin concentrations in the first morning urine according to age and sex in 2990 healthy children and adults.

This study was performed to clarify the changes in urinary albumin excretion according to age and sex in healthy subjects, for the appropriate judgment of microalbuminuria in insulin-dependent diabetes mellitus (IDDM). Concentrations of albumin in the first morning urine from 2990 healthy individuals (1713 males, 1277 females) aged from 6 to 39 years were measured by turbidimetry immunoassay. Reference values of the concentrations for each age group were obtained from the 95% confidence limits from the distribution simulated by the chi 2-test (k = 1). Reference values were 1.3-2.2 mg/dl in children aged 6-11 years. Values for females increased significantly from 22 mg/dl at age 11 years to 3.9 mg/dl at age 12 years (P < 0.0001) and those of males increased gradually from 1.7 mg/dl at age 11 years to 3.9 mg/dl at age 16 years. There were significant differences between males and females at the ages of 12 (P < 0.0001), 13 (P < 0.0001), and 14 (P < 0.0007). After 17 years, the values decreased from 3.9 mg/dl to 3.3 mg/dl in females, and to 2.9 mg/dl in males. We conclude that reference values of urinary albumin excretion change according to age and sex, which should be taken into consideration in the assessment of diabetic nephropathy in IDDM.

Adolescent↗

PubMed1992

[Mucoviscidosis screening with immunoreactive trypsin. Initial experiences in Austria].

Up to now, 16.338 IRT-measurements have been carried out on dried blood spot specimens; 15.505 of them were taken in the first week of life. Related to a provisionally chosen cut-off point of 750 ng/ml, 134 newborns (= 0.86%) showed an elevated IRT-value and subsequently were recalled between the fourth and sixth week of life for a second IRT-determination. Twenty-five out of 116 reinvestigated children again showed an elevated value, as based on likewise provisional, age-dependent reference values. Four of these children subsequently were identified as CF patients by sweat testing. So far, we did not encounter any false-negative IRT values. We also commenced to establish a profile of reference values for the first twelve weeks of life; as yet, there are not enough data for definitely defining these limits of normality. In conclusion, IRT-screening appears to be a reliable method for identifying CF patients in the newborn period. Our preliminary results indicate an incidence of CF of 1 to 3880 in the southeast of Austria.

Austria↗

PubMed2002

Longitudinal concentrations of vitamin B(12) and vitamin B(12)-binding proteins during uncomplicated pregnancy.

BACKGROUND: Because reference values for vitamin B(12) concentrations and vitamin B(12)-binding capacities for pregnant women have not been established, the reference values for nonpregnant women are often applied to assess vitamin B(12) status. The aim of the present study was to describe ranges of biochemical indices of vitamin B(12) status, including red blood cell (RBC) vitamin B(12), saturated and unsaturated cobalamin-binding proteins, and binding capacities in all trimesters of uncomplicated pregnancy. METHODS: A total of 39 healthy pregnant women with long-term daily intake of vitamin B(12) >2.6 microg/day and uncomplicated pregnancies participated in the study throughout their pregnancies. RBCs and serum vitamin B(12), holo-haptocorrin, unsaturated cobalamin-binding proteins, unsaturated and total vitamin B(12)-binding capacities, total homocysteine (tHcy), and RBC count were assessed in weeks 9-12, 20-22, and 36-38 of gestation. RESULTS: Significant changes in vitamin B(12) status occurred in the course of pregnancy. Serum vitamin B(12) concentrations and percentage of saturation of vitamin B(12)-binding proteins decreased steadily throughout pregnancy. In the third trimester, 35% of the participants had serum vitamin B(12) concentrations <150 pmol/L and 68.6% had <15% saturation of total vitamin B(12)-binding capacities, but no women had RBC vitamin B(12) concentrations <148 pmol/L. However, the decrease in these indices was not associated with reduced hemoglobin concentrations or RBC count or with increased tHcy concentrations. CONCLUSIONS: Our findings suggest that the reference values for vitamin B(12) status in nonpregnant women may not be applicable to pregnant women.

Diet↗

PubMed1981

Reference spirometric values using techniques and equipment that meet ATS recommendations.

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Humans↗

PubMed1989

Face cooling-induced reduction of plasma prolactin response to exercise as part of an integrated response to thermal stress.

This study was designed to verify if the decrease in blood prolactin (PRL) induced by selective face cooling during exercise could be part of a response to specific body thermal stress. Five healthy trained male cyclists presenting a significant plasma PRL elevation to exercise were, on three occasions and at weekly interval, submitted to a submaximal exercise (approx. 65% VO2max) on ergocycle with and without selective face cooling. In absence of face cooling a first trial served to establish reference values for workload, heart rate and plasma PRL levels, the latter increasing markedly (450% of resting values) in these conditions. On a second trial but with workload maintained at reference values (222 +/- 9 W), a significant bradycardia was observed with face cooling; furthermore, plasma PRL response to exercise was significantly reduced (to 31% of original response). On a third trial with face cooling, workload had to be significantly augmented (242 +/- 10 W) to maintain heart rate at reference level (78% HRmax); in addition, plasma PRL response to exercise was almost unchanged compared to the reference-value level. The absence of a significant face cooling-induced decrease in sympathetic tonus, as evaluated through peripheral plasma catecholamines response, does not indicate a role for the autonomic nervous system in the face cooling-induced reduction of both heart rate and PRL responses during exercise. Assay of circulating peripheral beta-endorphins could indicate that the face cooling-induced PRL blunted response does not necessarily involve an opioid mediation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed2003

Determination of reference range values indicative of glucose metabolism and insulin resistance by use of glucose clamp techniques in horses and ponies.

OBJECTIVES: To acquire reference range values indicative of glucose metabolism by use of the hyperglycemic clamp technique in healthy horses and evaluate the usefulness of the euglycemic hyperinsulinemic clamp technique in healthy horses and ponies. ANIMALS: Dutch Warmblood horses and 4 Shetland ponies. PROCEDURE: The hyperglycemic clamp technique was used for quantification of the sensitivity of beta cells to exogenous glucose infusion in horses. The euglycemic hyperinsulinemic clamp technique was used to determine the sensitivity and responsiveness of tissues to exogenous insulin in horses and ponies. RESULTS: During the hyperglycemic clamp technique, the mean amount of glucose metabolized (M) in horses was 0.011 +/- 0.0045 mmol/kg x min(-1) (95% confidence interval [CI], 0.0018 to 0.020 mmol/kg x min(-1); range, 0.000035 to 0.021 mmol/kg x min(-1)) and the mean M value-to-plasma insulin concentration (I) ratio (ie, mmol of glucose/kg x min(-1) per pmol of insulin/L x 100) was 0.017 +/- 0.016 (95% CI, -0.014 to 0.049; range, 0.000025 to 0.055). During the euglycemic hyperinsulinemic clamp technique, the mean M value was 0.014 +/- 0.0055 mmol/kg x min(-1) (95% CI, 0.0026 to 0.025 mmol/kg x min(-1); range, 0.0042 to 0.023 mmol/kg x min(-1)) in horses and 0.0073 +/- 0.0020 mmol/kg x min(-1) (95% CI, 0.0034 to 0.011 mmol/kg x min(-1); range, 0.0049 to 0.011 mmol/kg x min(-1)) in ponies. The M value was significantly lower in ponies than in horses, whereas the M:I ratios were not significantly different between horses and ponies. CONCLUSION AND CLINICAL RELEVANCE: Glucose clamp techniques offer good methods to investigate glucose metabolism in horses and ponies. A higher degree of insulin resistance was found in ponies, compared with Dutch Warmblood horses.

Animals↗

PubMed2005

Quantifying and evaluating ecosystem health: a case study from Moreton Bay, Australia.

As part of the program monitoring the ecosystem health of Moreton Bay, Queensland, Australia, we developed a means for assessing ecosystem health that allows quantitative evaluation and spatial representations of the assessments. The management objectives for achieving ecosystem health were grouped into ecosystem objectives, water quality objectives, and human health objectives. For the first two groups, aspects of the ecosystem (e.g., trophic status) were identified, and an indicator was chosen for each aspect. Reference values for each indicator were derived from management objectives and compared with the mapped survey values. Subregions for which the indicator statistic was equal to or better than the assigned reference value are referred to as "compliant zones." High-resolution surface maps were created from spatial predictions on a fine hexagonal grid for each of the indicators. Eight reporting subregions were established based on the depth and predicted residence times of the water. Within each reporting subregion, the proportion that was compliant was calculated. These results then were averaged to create an integrated ecosystem health index. The ratings by a team of ecosystem experts and the calculated ecosystem health indices had good correspondence, providing assurance that the approach was internally consistent, and that the management objectives covered the relevant biologic issues for the region. This method of calculating and mapping ecosystem health, relating it directly to management objectives, may have widespread applicability for ecosystem assessment.

Conservation of Natural Resources↗

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