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PubMed1996

Height and weight as a reflection of the nutritional situation of school-aged children working and living in the streets of Jakarta.

The nutritional status of 89 school-aged children living and working on the streets of Jakarta, Indonesia was assessed. Seventy-nine percent of the children were children "on" the street who still had regular contact with their families, whereas only 21% of the children were "of" the street who had only remote or no contact with their families. The mother was more likely to be present in the home of the children on the street than in the home of the children of the street. The average earning of the children was between 2000 and 3000 rupiah/day (U.S.S1 = 2000 Indonesian Rupiah). The distribution of height-for-age relative to the NCHS reference standard indicated that 52% of the children were stunted (below the third centile of the standard). However the distribution of weight-for height was close to that of the reference population standard, and only 7% of the children were wasted (below the third centile of the standard). Comparison of the data from these street children weigh more and are taller than their socio-economic peers.

Adolescent↗
PubMedDate not supplied

Cross-sectional growth standards for captive baboons: II. Organ weight by body weight.

We present the first cross-sectional organ weight by body weight reference standards for captive baboons (Papio hamadryas). Organ weight data were obtained from necropsy reports for 634 healthy, pedigreed, captive female and male baboons. From summary statistics we calculated and fit cross-sectional sex-specific percentile curves for: adrenals, brain, eyes, heart, kidneys, liver plus gall bladder, lungs, pancreas, pituitary gland, spleen, and thyroid gland in three kilogram body weight intervals and cross-sectional summary statistics by sex for each organ in one kilogram body weight intervals.

Animals↗
PubMed1994

Research on standards for professional licensure and certification examinations.

The purpose of this article is to outline an agenda for research on standards for professional licensure and certification examinations. To avoid confusion, scores are defined as content-based decisions about the correctness of responses, and standards refer to the educational/social decisions about how many questions need to be answered correctly to pass. Standards are the focus of this article. The two major types of standards, relative and absolute, are described and the major standard-setting methods for each are presented. Some of the published results in four different areas are reviewed: (a) basis of the judgements, (b) efficiency of the process, (c) group effects, and (d) content and expertise effects. Topics for future research in all four areas are identified.

Certification↗
PubMed1999

Matrix interferences in the analysis of digested biological tissues with inductively coupled plasma-mass spectrometry.

To investigate the physiological roles or toxicity of trace or toxic elements, multielement analysis of limited quantities of samples in the biological tissues is required. Inductively coupled plasma mass spectrometry (ICP-MS) suits this requirement, but spectral and nonspectral interferences are inevitable. We examined correction methods for the nonspectral interferences by analyzing signals of 21 elements in various concentrations of HNO3 as well as five major elements (Na, K, P, Ca, and Cl). Using internal standards, the interferences caused by the major elements were corrected, but the interferences caused by HNO3 were impossible to correct for elements with high ionization potentials. The analytical results using the standard addition method on 14 elements in standard reference materials and fresh brain tissues confirmed the accuracy of this method. Thus, we concluded that the standard addition method is useful to correct for the nonspectral interferences.

Artifacts↗
PubMed1991

Prostate-specific antigen: problems in analysis.

We have compared an "in-house" Tenovus Institute prostate-specific antigen (PSA) assay with four different commercial kits (ELSA-PSA, IRMA-Count PSA, PROS-CHECK PSA and TANDEM-R PSA) that are available in the UK. There was only good correlation and linear regression parameters between the in-house assay and one of the kit methods. The difference in values for the same sample ranged from 2 to 100-fold. These discrepancies are due, in part, to the specificity of the polyclonal and monoclonal antibodies used in the procedures and the differing "hook effects" caused by the binding capacity of the antibody pairs in the immunometric assays. Discrepancies will, however, result from the differing potencies of the standards used for the calibration curves. This data highlights the urgency for the introduction of an internationally accepted reference standard for PSA.

Antigens, Neoplasm↗
PubMed1975

Human pituitary gonadotropin index. I. Standardized LRH test criteria for evaluation of functional amenorrhea.

LRH test were carried out by giving 339 amenorrheic women and 74 normally menstruating volunteers an intravenous injection of 25 mug LRH (Hoe 471). Plasma LH and FSH were measured by RIA in two laboratories (Tuebingen and Ulm) using two standard reference preparations: LER 907 and 2nd IRP-HMG. The average conversion factors between the two standard preparations were calculated at 5.0 for LH and 25.0 for FSH. Furthermore, the estradiol-17beta levels were measured in 139 out of the 339 patients immediately before and 60 minutes after LRH injection. Taking the episodic and cyclic plasma gonadotropin fluctuations into consideration a shorthand system classifying the gonadotropin baseline (BI-BIV) and LH responses to 25 mug LRH (R0-R2) has been established and is referred to as Human Pituitary Gonadotropin Index (HPGI). It is possible to achieve reproducible gonadotropin results in two different laboratories using two different standard reference preparations. Two separate, randomly selected groups of amenorrheic women were found to have the same percent distribution of the HPGI. A correlation coefficient of r equal 0.67 between basal and LRH stimulated plasma LH levels does not sufficiently characterize the individual LH response behavior. A significant increase of plasma LH and FSH within the test period (60') reveals that the iv administration of 25 mug LRH represents an adequate dose for the LRH test in women. The HPGI which characterizes the functional state of gonadostat, may become a useful diagnostic index for evaluating women with anovulatory disease before, during, and after therapy.

Adolescent↗
PubMed2003

Cerebral palsy and intrauterine growth in single births: European collaborative study.

BACKGROUND: Cerebral palsy seems to be more common in term babies whose birthweight is low for their gestational age at delivery, but past analyses have been hampered by small datasets and Z-score calculation methods. METHODS: We compared data from ten European registers for 4503 singleton children with cerebral palsy born between 1976 and 1990 with the number of births in each study population. Weight and gestation of these children were compared with reference standards for the normal spread of gestation and weight-for-gestational age at birth. FINDINGS: Babies of 32-42 weeks' gestation with a birthweight for gestational age below the 10th percentile (using fetal growth standards) were 4-6 times more likely to have cerebral palsy than were children in a reference band between the 25th and 75th percentiles. In children with a weight above the 97th percentile, the increased risk was smaller (from 1.6 to 3.1), but still significant. Those with a birthweight about 1 SD above average always had the lowest risk of cerebral palsy. A similar pattern was seen in those with unilateral or bilateral spasticity, as in those with a dyskinetic or ataxic disability. In babies of less than 32 weeks' gestation, the relation between weight and risk was less clear. INTERPRETATION: The risk of cerebral palsy, like the risk of perinatal death, is lowest in babies who are of above average weight-for-gestation at birth, but risk rises when weight is well above normal as well as when it is well below normal. Whether deviant growth is the cause or a consequence of the disability remains to be determined.

Birth Weight↗
PubMed2002

Defining nutritional status of women in developing countries.

OBJECTIVE: To define a de facto reference body mass index (BMI) for women in developing countries and compare its performance with the Quetelet BMI. DESIGN: A logarithmic equation for elite wt/ht references was developed using the weight (wt) and height (ht) of 10,524 non-pregnant elite mothers. Functional outcomes were compared using both BMIs. SETTING: Forty-six national surveys from 36 developing countries. SUBJECTS: Mothers 15-49 years old. RESULTS: The defacto reference standard deviation showed 2.2% of elite women were undernourished and 6.3% overnourished; lower and upper limits for 'ideal' wt/ht were 73% and 137%, respectively. Compared with the age-based and medium frame standards of the First and Second National Health and Nutrition Examination Surveys (NHANES I & II), the defacto reference defined fewer women as undernourished (5.3% vs. 10.5% and 14.4%, respectively), but more as overnourished (20.4% vs. 13.7% and 15.9%, respectively). In the de facto reference, BMI = wt/ht(1.6). Using the age-based and medium-frame-based Quetelet BMI (wt/ht2), 28.5% and 31.7% had a low and 13.0% and 14.7% a high BMI, respectively. For the defacto reference, 18.4% of the elite mothers had a low BMI and 19.3% a high BMI. Applying the de facto reference to all women showed that the distribution of BMI was similar irrespective of the reference used. Functional outcomes were similar for both BMIs. CONCLUSIONS: The NHANES I & II growth curves define more women as overnourished than the de facto curve, but the opposite for defining the undernourished. Functional outcomes were similar for both BMIs, suggesting there is no great advantage to using a defacto BMI based on national-level data from these 46 national surveys.

Adolescent↗
PubMed2004

CT brain prescriptions in Talairach space: a new clinical standard.

BACKGROUND AND PURPOSE: Head CT prescriptions are currently plagued by intra- and intersubject image variance and do not match standardized MR imaging planes. We developed and tested a simple method to improve CT precision and approximate the Talairach reference standard advocated for MR imaging. METHODS: We retrospectively reviewed midline sagittal T2-weighted brain MR images of 126 consecutive patients to determine the mean angle subtended by the Talairach anterior commissure-posterior commissure (AC-PC) line and the hard palate. On the basis of this data set, a new head CT protocol was instituted with pitch similarly prescribed relative to the hard palate as identified on the lateral CT scout film. We then compared the precision of the new protocol, our former method (nominally parallel to the orbito-meatal line) and fixed-gantry angulation. Two head CT studies from 50 consecutive patients imaged with our old protocol and 50 consecutive patients imaged with our new protocol were reviewed for a total of 200 CT examinations. RESULTS: The Talairach AC-PC line was rotated 12.0 degrees +/- 6.1 degrees from the hard palate line and 15.6 degrees +/- 10.1 degrees from the axial plane of the magnet. The new CT protocol approximated the Talairach-referenced MR images obtained at our institution and improved intrapatient CT scan precision compared with fixed-gantry selection (P <.004) and compared with our previous prescription technique (P <.064; P <.025, controlling for excessive head extension). CONCLUSION: By prescribing CT images angled +12 degrees from the hard palate, a structure readily identified by technologists, interscan precision can be improved and Talairach-referenced MR imaging studies can be approximated. Along with AC-PC-referenced MR imaging studies, we advocate this CT protocol as a new clinical standard.

Adolescent↗
PubMed1981

A candidate reference method for determination of total protein in serum. I. Development and validation.

We developed a candidate Reference Method for measuring total serum protein by use of the biuret reaction. The method involves a previously described biuret reagent (Clin. Chem. 21: 1159, 1975) and Standard Reference Material (SRM) 927 bovine albumin (National Bureau of Standards) as the standard. At 25 degrees C, color development for 30 or 60 min provides identical serum protein values. Glucose (up to 10 g/L) and bilirubin (up to 300 mg/L) do not interfere. Hemoglobin, at 3 g/L, increases apparent serum protein by 0.4 g/L. The presence of dextran in serum causes easily detected turbidity, but this interference can be eliminated by centrifuging the reaction mixture. Therapeutic concentrations of ampicillin, carbenicillin, penicillin, oxacillin, nafcillin, chloramphenicol, cephalothin, and methicillin in blood do not interfere, nor do triglycerides up to 10 g/L. Within-run and day-to-day standard deviations of the method are 0.1 and 0.4 g/L, respectively.

Bilirubin↗
PubMed1979

An improved gas-liquid chromatographic procedure for the determination of amitriptyline and nortriptyline levels in plasma using nitrogen-sensitive detectors.

An improved gas-liquid chromatographic procedure for the plasma level determination of amitriptyline and nortriptyline using nitrogen-sensitive detectors is described. Derivatization of the secondary amines using trifluoroacetic anhydride greatly improves the response and reproducibility of the assay. Plasma samples containing as little as 5 ng/ml of amitriptyline and nortriptyline can be assayed precisely and reproducibly, using protriptyline as internal reference standard.

Amitriptyline↗
PubMed1993

Protein adsorption studies on 'standard' polymeric materials.

Adsorption of fibrinogen from buffer as a single protein and from plasma to four materials has been studied. The two NIH-NHLBI primary reference standards, filler free polydimethylsiloxane and low density polyethylene, were used along with polyvinylcholoride and cellulose materials supplied by the IUPAC Working Party. The materials were examined in both film and tubing form, except for polydimethylsiloxane which was studied only in tubing form. Adsorption was measured at room temperature using 125I-labelled fibrinogen. The order of adsorbed amounts in the single protein experiments was found to be: cellulose < PVC < PE = PDMS. Apparent adsorption affinities are in the same order. In plasma, all surfaces except cellulose showed maxima in adsorption as a function of plasma concentration after 5 min contact. This is indicative of initial adsorption followed by displacement of fibrinogen (the Vroman effect). Cellulose showed very low adsorption of fibrinogen from plasma. The Vroman maxima were more pronounced on the tubing samples than on the films, and, as for the single protein experiments, adsorption was found to be less on tubing than on film samples. A tentative interpretation of the Vroman effect data suggests that the order of procoagulant activity of the materials may be: PDMS = PE < PVC < cellulose.

Adsorption↗
PubMed1983

Rat caries assay of reference foods and sugar-containing snacks.

Using standard reference snack foods, we tested a method, using rats fed in a programmed feeding machine, to evaluate the caries-promoting properties of foods. Results, which were expressed in relation to a control food, indicate that the method distinguished differences in caries potential among a number of different snack foods. Buccal and sulcal caries scores of rats fed snacks foods varied in their responses. A gel diet used to provide essential nutrients for the rat growth in this approach contributed minimally to the caries response which was related principally to the food being tested.

Animals↗
PubMed1998

Three-dimensional laser imaging system for measuring wound geometry.

BACKGROUND AND OBJECTIVE: A low cost laser imager was designed and fabricated for measurement of wound geometry. METHODS: The accuracy of the imager was validated using reference depressions of known dimensions. Perimeter, area, and volume were compared to planimetric and packing techniques on simulated wound models. RESULTS: Wound tracing and alginate measurement methods required approximately 20 times longer for the reference standards, and 11 times longer for the simulated wounds than with the laser scanning method (LSM). LSM consistently overestimated the reference perimeter by 0.73+/-0.20 cm and the area by 0.98+/-0.62 cm2. Volume estimates were not statistically different. The tracing method underestimated the perimeter by 0.34+/-0.27 cm and the area by 1.07+/-1.09 cm2. Volume measurements by the alginate method were not statistically different. The perimeters of the simulated wounds averaged 1.29+/-0.27 cm greater using the LSM than obtained by the tracing method, and areas greater by 2.02+/-1.30 cm2. Volume scans averaged 1.04+/-0.61 cm3 greater than by the alginate method.

Analysis of Variance↗
PubMed1996

Lipoprotein(a) in health and disease.

Lipoprotein(a) [Lp(a)] represents an LDL-like particle to which the Lp(a)-specific apolipoprotein(a) is linked via a disulfide bridge. It has gained considerable interest as a genetically determined risk factor for atherosclerotic vascular disease. Several studies have described a correlation between elevated Lp(a) plasma levels and coronary heart disease, stroke, and peripheral atherosclerosis. In healthy individuals, Lp(a) plasma concentrations are almost exclusively controlled by the apo(a) gene locus on chromosome 6q2.6-q2.7. More than 30 alleles at this highly polymorphic gene locus determine a size polymorphism of apo(a). There exists an inverse correlation between the size (molecular weight) of apo(a) isoforms and Lp(a) plasma concentrations. The standardization of Lp(a) quantification is still an unresolved task due to the large particle size of Lp(a), the presence of two different apoproteins [apoB and apo(a)], and the large size polymorphism of apo(a) and its homology with plasminogen. A working group sponsored by the IFCC is currently establishing a stable reference standard for Lp(a) as well as a reference method for quantitative analysis. Aside from genetic reasons, abnormal Lp(a) plasma concentrations are observed as secondary to various diseases. Lp(a) plasma levels are elevated over controls in patients with nephrotic syndrome and patients with end-stage renal disease. Following renal transplantation, Lp(a) concentrations decrease to values observed in controls matched for apo(a) type. Controversial data on Lp(a) in diabetes mellitus result mainly from insufficient sample sizes of numerous studies. Large studies and those including apo(a) phenotype analysis came to the conclusion that Lp(a) levels are not or only moderately elevated in insulin-dependent patients. In noninsulin-dependent diabetics, Lp(a) is not elevated. Conflicting data also exist from studies in patients with familial hypercholesterolemia. Several case-control studies reported elevated Lp(a) levels in those patients, suggesting a role of the LDL-receptor pathway for degradation of Lp(a). However, recent turnover studies rejected that concept. Moreover, family studies also revealed data arguing against an influence of the LDL receptor for Lp(a) concentrations. Several rare diseases or disorders, such as LCAT- and LPL-deficiency as well as liver diseases, are associated with low plasma levels or lack of Lp(a).

Animals↗
PubMed1992

Age-related changes of urinary urea. Epidemiological study in children from southern Italy living in Cimitile.

Urinary urea was measured, under normal living conditions, in children aged 3-16 years, from Cimitile, a small town near Naples in Southern Italy. Urinary urea correlated with age, height, weight, body mass index and body surface area, and was independent from sex. Urinary urea also correlated with urinary creatinine, uric acid, oxalate, sodium and phosphate. Protein intake assessed from urea excretion was 2.66 +/- 0.66 g/kg at 3 years of age and 1.49 +/- 0.31 g/kg at 16 years, and exceeded Italian standards for recommended intake. Also, the height and weight of the children living in Cimitile, with few exceptions, were in excess of national reference standards.

Adolescent↗
PubMed1980

Rheumatoid factor test performance on CAP survey specimens.

The participant performances on 1979 rheumatoid factor test survey specimens are tabulated. All reagents performed well on the qualitative positive and negative specimens. Prominent differences in results occurred with the weakly positive specimen. Some reagents consistently gave higher titers on the positive specimen, indicating the need for reference standards.

Agglutination Tests↗
PubMed1996

NIST SRM 1945, whale blubber, NIST SRM 1974a, organics in mussel tissue, and NIST SRM 1941a, organics in marine sediment as certified reference materials for polychlorinated dioxins and furans in marine ecosystems.

Few natural matrix Standard Reference Materials are available for the validation of analytical methods measuring polychlorinated dioxins and furans (PCDDs and PCDFs) in marine ecosystems. The concentrations of PCDDs and PCDFs in NIST SRM 1945, SRM 1974a, and SRM 1941a are of interest because the analysis of marine mammal, mussel tissues and sediments have become important tools in the determination of organochlorine contamination of the environment. Because these SRMs have been demonstrated to be homogenous for other organic contaminants, they would be expected to be reliable standards for validation of polychlorinated dioxins and furans in marine mammals, mussels and sediments as well.

Animals↗