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PubMedDate not supplied

Reliability of spot samples for assessment of urinary excretion of pyridinoline in patients with rheumatoid arthritis.

OBJECTIVE: To determine how well a spot urine sample of patients with active rheumatoid arthritis (RA) can predict 24-hour urinary pyridinoline and deoxypyridinoline excretion. METHODS: Urine samples of 11 hospitalized RA patients taken on 2 consecutive days at 8 a.m. and 4 p.m. were compared with samples from 24-hour collections (gold standard). High-performance liquid chromatography was used to measure the collagen crosslink concentrations. RESULTS: Sampling time was the only significant factor (repeated measurement ANOVA). Significant differences were found between morning and 24-hour samples and between morning and afternoon samples, but not between afternoon and 24-hour samples. CONCLUSIONS: Samples collected in the afternoon (4 p.m.) give the best approximation of 24-hour urinary pyridinoline excretion in patients with active rheumatoid arthritis. In longitudinal studies the sampling time should be fixed.

Adult↗
PubMedDate not supplied

Air Sampling System for use in monitoring viable and non-viable particulate air quality under dynamic operating conditions of blow/fill/seal processing.

An Air Sampling Link (ASL), employed in conjunction with an Air Sampling Device (ASD) or a laser particle counter, has been developed for sampling flowing air for viable and non-viable particulate analyses. Typically, the ASL could be used to sample filtered air supplied to an air shower of a Blow/Fill/Seal machine operating in the dynamic state. The ASL allows sample volumes of air to be taken from flowing air without significant loss from the sample flow of airborne particles possessing aerodynamic sizes relevant to those found in practice. The link has no moving parts, is steam sterilizable in-situ, and allows for the taking of continuous samples of air without the need for intervention into the 'critical zone' of the filling machine. This article describes (i) the design criteria for the ASL and the ASD, (ii) the rationale underlying the concept of the ASL design, (iii) the collection performance of the ASL against that of a conventional sampling arrangement, and (iv) a functionality assessment of the ASL-based sampling system installed on a Rommelag style 305 B/F/S machine over a seven week period.

Air Microbiology↗
PubMed2002

Automated time-resolved immunofluorometric assay for Toxoplasma gondii-specific IgM and IgA antibodies: study of more than 130,000 filter-paper blood-spot samples from newborns.

BACKGROUND: To screen for congenital toxoplasmosis, we developed a time-resolved immunofluorometric assay for the simultaneous detection of Toxoplasma gondii-specific IgM and IgA in filter-paper samples collected from newborns 4-7 days after birth. METHODS: The assay was performed on the AutoDELFIA, and results were calculated based on the ToxoM WHO Third International Reference Serum. Comparison with an in-house mu-capture immunoassay was carried out retrospectively on filter-paper samples from children with confirmed congenital toxoplasmosis. Prospectively the assay was compared with a mu-capture immunoassay on 68 394 samples and a commercially available assay on another 69,467 samples. Before serum was requested from the newborn, positive samples were tested for IgA and IgM separately and in an IgM-immunosorbent agglutination assay developed for filter-paper samples. RESULTS: Intra- and interassay variations (CVs) were 8% and 16%, respectively. The cutoff of 5 units/mL produced a 0.5% retest rate. The assay detected 13 of 18 (72%) samples from newborns diagnosed with congenital toxoplasmosis in the retrospective study. Prospectively, the assay identified 24 newborns who were later diagnosed with congenital toxoplasmosis. Results for all 24 cases were positive by the respective comparison method. No cases were detected solely by the IgA antibodies in the sample. CONCLUSION: Neonatal screening for congenital toxoplasmosis can be automated by use of purified europium-labeled antigen for detection of T. gondii-specific IgM and IgA eluted from filter-paper samples.

Animals↗
PubMed2003

Sequence alterations in the reduced folate carrier are observed in osteosarcoma tumor samples.

High-dose methotrexate is a standard component of therapy for high-grade osteosarcoma. Its effectiveness may be limited by intrinsic and acquired resistance. Decreased reduced folate carrier (RFC) expression has been shown in approximately half of osteosarcomas at diagnosis. Mutations and polymorphisms in the RFC gene have been reported in various cell lines. The purpose of this study was to investigate sequence alterations in the RFC gene in osteosarcoma tumor samples. The entire coding region of the RFC gene in samples from 162 osteosarcoma patients was screened by DNA single-stranded conformational polymorphism, followed by direct sequencing of any region with altered mobility. A previously identified polymorphism at cDNA position number 174 of RFC exon 2 was observed. Sixty-one samples (37.6%) were heterozygous with both A/G at this position (His(27)/Arg(27)), 52 samples (32.2%) were homozygous with G (Arg(27)), and 49 samples (30.2%) were homozygous with A (His(27)). Fifteen (9.2%) samples were identified with other RFC sequence variants in exon 2, none of which have been reported. The sequence variants in exon 2 included a G to A substitution at cDNA position 231, a G to A substitution at cDNA position 155, a C to T substitution at cDNA position 114, and a T to C substitution at cDNA position 104, resulting in a serine to asparagine substitution at amino acid 46, a glutamate to lysine substitution at amino acid 21, an alanine to valine substitution at amino acid 7, and a serine to proline substitution at amino acid 4, respectively. A deletion of A at cDNA position 126 resulting in a frameshift was also observed. Some of these variants were observed in multiple samples. Eight samples had altered single-stranded conformational polymorphism patterns in exon 3 that were associated with nucleotide changes that altered the amino acid sequence. All of these RFC sequence variants appeared to be heterozygous. Heterozygous C/T and homozygous C also were observed at RFC cDNA position 790 in exon 3, which does not alter the amino acid coding sequence. This study shows that RFC sequence alterations are frequent in samples from osteosarcoma patients. Additional studies are under way to determine the clinical significance of these sequence alterations and their effect on methotrexate transport and resistance.

Amino Acid Sequence↗
PubMedDate not supplied

[Comparative studies with three different bovine blood sample BHV-1 ELISA tests: indirect ELISA and bG-blocking-ELISA].

A total of 2754 bovine blood samples were examined for BHV1 antibodies in three different BHV-1 ELISA tests. The tests used were the CHEKIT Trachitest 2nd. Gen. "Bestätigungstest" Serum, the CHEKIT-BHV-1-gB-ELISA (Bommeli-Diagnostics/Intervet), and the BHV-1-gB Antibody Test Kit (IDEXX). A first testing identified 111 (4.0%) of the samples as positive and 2501 (90.8%) samples negative in all three tests. Onehundredand-fortytwo (5.2%) of the samples showed a not negative result in at least one of the two gB-ELISAs. The testing was repeated for 139 of the 142 samples and still 89 (3.2%) samples were found with discrepant results. The remaining 50 samples showed a negative reaction in the three ELISA tests. After Western blot analysis antibodies against glycoprotein B (gB) of BHV-1 were only detected in 11 of the 89 samples with a not negative reaction in at least one of the gB-ELISAs. Three of the 50 ELISA-negative samples showed a positive reaction in the Western blot. The high number of positive results in the gB-ELISAs which were negative in the Western blot assay leads to the conclusion that gB-ELISAs may have a lower specificity as the indirect ELISA. Introducing the gB-ELISA as the standard test for BHV1 serology in Bavaria would result to an increase of the number of BHV-1 positive farms by 8% (gB IDEXX) or 20% (gB Bommeli) 20%.

Animals↗
PubMedDate not supplied

Evaluation of sampling plans to detect Cry9C protein in corn flour and meal.

StarLink is a genetically modified corn that produces an insecticidal protein, Cry9C. Studies were conducted to determine the variability and Cry9C distribution among sample test results when Cry9C protein was estimated in a bulk lot of corn flour and meal. Emphasis was placed on measuring sampling and analytical variances associated with each step of the test procedure used to measure Cry9C in corn flour and meal. Two commercially available enzyme-linked immunosorbent assay kits were used: one for the determination of Cry9C protein concentration and the other for % StarLink seed. The sampling and analytical variances associated with each step of the Cry9C test procedures were determined for flour and meal. Variances were found to be functions of Cry9C concentration, and regression equations were developed to describe the relationships. Because of the larger particle size, sampling variability associated with cornmeal was about double that for corn flour. For cornmeal, the sampling variance accounted for 92.6% of the total testing variability. The observed sampling and analytical distributions were compared with the Normal distribution. In almost all comparisons, the null hypothesis that the Cry9C protein values were sampled from a Normal distribution could not be rejected at 95% confidence limits. The Normal distribution and the variance estimates were used to evaluate the performance of several Cry9C protein sampling plans for corn flour and meal. Operating characteristic curves were developed and used to demonstrate the effect of increasing sample size on reducing false positives (seller's risk) and false negatives (buyer's risk).

Algorithms↗
PubMed1992

Sample size requirements for addressing the population genetic issues of forensic use of DNA typing.

DNA typing offers a unique opportunity to identify individuals for medical and forensic purposes. Probabilistic inference regarding the chance occurrence of a match between the DNA type of an evidentiary sample and that of an accused suspect, however, requires reliable estimation of genotype and allele frequencies in the population. Although population-based data on DNA typing at several hypervariable loci are being accumulated at various laboratories, a rigorous treatment of the sample size needed for such purposes has not been made from population genetic considerations. It is shown here that the loci that are potentially most useful for forensic identification of individuals have the intrinsic property that they involve a large number of segregating alleles, and a great majority of these alleles are rare. As a consequence, because of the large number of possible genotypes at the hypervariable loci that offer the maximum potential for individualization, the sample size needed to observe all possible genotypes in a sample is large. In fact, the size is so large that even if such a huge number of individuals could be sampled, it could not be guaranteed that such a sample was drawn from a single homogeneous population. Therefore adequate estimation of genotypic probabilities must be based on allele frequencies, and the sample size needed to represent all possible alleles is far more reasonable. Further economization of sample size is possible if one wants to have representation of only the frequent alleles in the sample, so that the rare allele frequencies can be approximated by an upper bound for forensic applications.

Alleles↗
PubMedDate not supplied

Tyrosinase mRNA RT-PCR analysis as an additional diagnostic tool for the identification of melanoma cells in biological fluid samples other than blood: a preliminary report.

Reverse transcription polymerase chain reaction (RT-PCR) of tyrosinase mRNA has been applied for the detection of melanoma cells in the peripheral blood, lymph nodes and bone marrow of melanoma patients. We evaluated the diagnostic accuracy of RT-PCR in comparison to standard cytology and immunocytochemistry (ICC) for the identification of melanoma cells in biological fluids other than blood. Tyrosinase expression was evaluated together with standard cytology and ICC (anti-S100, HMB-45 and Melan-A antibodies) in biological fluid samples collected from 17 melanoma patients according to the site of metastatic involvement or clinical suspicion (eight cerebrospinal fluid (CSF) samples; three pleural effusions; four ascites; one bile sample, one pericardial effusion); 17 samples collected from patients with non-melanoma metastatic cancer were used as controls. Tyrosinase expression in the biological fluid sample was compared with the expression determined at the same time in peripheral blood. Positive tyrosinase expression was found in 12/17 melanoma and 3/17 non-melanoma cancer patients. Cytology/ICC showed the presence of neoplastic cells in only 7/12 melanoma samples with positive tyrosinase expression: radiological evidence of disease involvement was found in all these patients (three meningeal, two pleural, two peritoneal). Clear-cut radiological evidence of disease involvement at the sampling site was found in the five patients with negative cytology/ICC and positive RT-PCR (one CSF; four serous membrane effusions); all patients died of disease progression within four months of sampling. The five patients who were negative for both cytology/ICC and RT-PCR did not show any clinical evidence of disease recurrence at the sampling site. Only five of the 12 metastatic patients with positive tyrosinase expression in biological fluid showed positivity for tyrosinase in the peripheral blood. These preliminary results suggest that the analysis of biological fluids other than blood could be considered as a new potential clinical field of application for the tyrosinase mRNA assay.

Adult↗
PubMed1994

Application of the Inverness Blood Grouping System for semiautomated ABO and D testing of patients' samples.

We evaluated the performance of the Inverness Blood Grouping System (IBG Systems, Inc., Laytonsville, MD) for the ABO and D red cell grouping of patients' samples. The IBG System is a semiautomated microplate device for blood grouping and antibody detection We tested 2,051 samples using the IBG System and by manual grouping techniques. In no instance did the IBG System give a final ABO interpretation different from the final manual technique. For three samples, the JBG System's ABO interpretation was different from the manual interpretation. An error in interpretation by the technologist performing the manual testing was responsible for the discrepancies. The IBG System identified one sample as D-positive that was grouped as D-negative by manual testing. The patient's sample had been previously grouped manually as a weak D. Au other D results were in agreement. The IBG System provided ABO interpretatinns without technologist's intervention on 1,765 (86.1%) of the samples. In 153 (7.5%) of the samples, a single, equivocal reaction required visual inspection, but no repeat testing was necessary. In 133 (6.5%) of the samples, either repeat testing or reliance on only the manual results was required for final ABO group interpretation. The IBG System is a reliable and efficient alternative to manual techniques for ABO and D grouping of patients' samples.

Journal Article↗
PubMed2005

Detection of Japanese encephalitis (JE) virus-specific IgM in cerebrospinal fluid and serum samples from JE patients.

Detection of Japanese encephalitis virus (JEV)-specific IgM by IgM-capture enzymed-linked immunosorbent assay (IgM-capture ELISA) has been accepted as the standard for serological diagnosis. In the present study, we analyzed the time course of the positive rate of JEV-specific IgM in serum and cerebrospinal fluid (CSF) specimens from confirmed JE patients. Serum and CSF samples were obtained from 155 JE cases for diagnostic purposes at hospitals in Thailand from 2002 to 2004. The levels of specific IgM were assessed by IgM-capture ELISA in the 171 serum and 156 CSF samples. Anti-JEV IgM was detected in 26 of 44 serum samples collected on days 1-4 of the disease period, in 31 of 44 samples collected on days 5-8, in 23 of 26 samples collected on days 9-12, and in all the samples collected on day 13 or later. Specific IgM was detected in 60 of 66 CSF samples collected on days 1-4 of illness, and in all the CSF samples but one collected on day 7 or later. The results indicate that the detection of JEV-specific IgM in CSF by IgM-capture ELISA is a reliable laboratory diagnostic method for confirmation of JE throughout the disease period, while the detection of IgM in serum samples is a reliable method on day 9 or later.

Antibodies, Viral↗
PubMed2006

National Survey of Family Growth, Cycle 6: sample design, weighting, imputation, and variance estimation.

OBJECTIVES: Cycle 6 of the National Survey of Family Growth (NSFG) was conducted by the National Center for Health Statistics in 2002 and early 2003. This report describes how the sample was designed, shows response rates for various subgroups of men and women, describes how the sample weights were computed to make national estimates possible, shows how missing data were imputed for a limited set of key variables, and describes the proper ways to estimate sampling errors from the NSFG. The report includes both nontechnical summaries for readers who need only general information and more technical detail for readers who need an in-depth understanding of these topics. METHODS: The NSFG Cycle 6 was based on an independent, national probability sample of men and women 15-44 years of age. It was the first NSFG ever to include a national sample of men 15-44 as well as a sample of women. Fieldwork was carried out by the University of Michigan's Institute for Social Research (ISR) under a contract with NCHS. In-person, face-to-face interviews were conducted by professional female interviewers using laptop computers. In all, 12,571 women and men-7,643 females and 4,928 males-were interviewed, the largest NSFG ever done. RESULTS: Analysis of NSFG Cycle 6 data requires the use of sampling weights and estimation of sampling errors that accounts for the complex sample design and estimation features of the survey. Examples of how to use several available software packages that incorporate complex design features in estimation, such as SAS, SUDAAN, and STATA, are presented.

Adolescent↗
PubMed1990

Increased migration rate observed in DNA from evidentiary material precludes the use of sample mixing to resolve forensic cases of identity.

The analysis of restriction fragment length polymorphisms in forensic DNA samples can be used to determine whether any two or more samples have the same biological origin. However, sometimes DNA recovered from evidentiary material, such as blood or semen stains, migrates at a different rate than an exemplar sample. This difference in migration, while maintaining the same overall pattern, produces a shift in the position of the bands. To verify that a shift in migration has occurred between evidence and exemplar samples, we have utilized two DNA probes that recognize DNA fragments that do not vary in size between individuals (monomorphic). The results obtained with this type of internal control show that differences in migration rate between exemplar and evidentiary samples can be recognized and accounted for and do not affect the ability to decide whether two patterns match. A common practice in many analytical tests, to show identity between two samples, is to test the properties of the samples individually and mixed. However, this approach is not applicable to all forensic DNA identity tests. In many cases, DNA from forensic samples may be irreversibly modified and this can alter the migration rate of the DNA samples. Thus, in a mixture of DNA from exemplar and evidence, the same polymorphic DNA fragments may not comigrate and produce a composite pattern which could lead to false exclusions.

DNA↗
PubMed1990

Computer assisted efficiency testing of different sampling methods for selective nuclear graphic tablet morphometry.

Selective nuclear graphic tablet morphometry is widely employed as a useful tool in quantitative pathological assessments. The value of such a measuring system is strongly determined by the sampling rule that has to ensure high measurement precision with minimal effort. Therefore, the efficiency of four different random sampling methods (i.e., the pure "random," "zone," "at convenience," and "raster" methods) was tested by means of computer simulated sampling in nuclear study populations derived from histological sections of three endometrial hyperplasias and nine endometrial carcinomas. The 12 nuclear study populations each consisted of 1000 intact nuclei that were systematically measured within demarcated measurement fields by an experienced morphometrist. To attain an arbitrarily chosen measurement precision of 2.5% the computer simulations showed that the random and the raster methods required much smaller sample sizes than the zone and at convenience methods. By using the random and raster methods for assessment of the nuclear area, a maximal sample size of 200 nuclei was necessary, whereas the zone and at convenience methods mostly required more than 200 nuclei. For features such as the perimeter, longest axis, shortest axis, and two shape factors (form-PE and roundness), and the same level of precision, the sample size could be considerably smaller. The differences in efficiency can be explained by the existence of clustering and gradients in the value distribution of a nuclear feature within the measurement field. In contrast to the zone and at convenience methods, the random and raster methods sample nuclei from the entire measurement field and thus do not limit sampling to only a few larger areas within that field. Consequently, the latter two sampling methods cope better with an uneven spatial distribution in the magnitude of a nuclear feature and can thereby help to keep the measurement reproducibility high.

Analysis of Variance↗
PubMedDate not supplied

Cytologic diagnosis by transthoracic fine needle sampling without aspiration.

The cytologic findings of transthoracic fine needle sampling without aspiration (fine needle capillary [FNC] sampling) are reported. Eleven patients were examined by FNC sampling while four were examined by the classic fine needle aspiration (FNA) method. In contrast to FNA sampling, FNC sampling produced less patient trauma and admixture of the sample with blood, while giving a better perception of the tumor and its consistency. The quality of the samples obtained by the FNC technique was equal to that of the FNA samples. The results demonstrate that fine needle sampling without aspiration may be used in the study of deep-seated as well as of superficial organs.

Biopsy, Needle↗
PubMed1989

Comparable laboratory performances in the analysis of lead in control samples and in fresh human blood.

The validity of quality control programs is based on the assumption that the control samples can be commuted with the real samples, so that, according to the results obtained by a given laboratory on control samples, it is possible to produce reasonable predictions about the reliability of results obtained on real samples. During the implementation of a program of biological monitoring of the general population against the risk of saturnism, a great number of data have been collected allowing the evaluation--as far as blood lead determination is concerned--of the real predictive power of the results obtained by a laboratory during a quality control program, according to its specific level of analytical reliability. The results obtained by eleven laboratories in the analysis of control samples have been compared, by regression analysis, with the results obtained on the same samples by the reference laboratory. The same procedure has been adopted for the results obtained by each laboratory and by the reference laboratory in the duplicate analysis of about 10% of the real samples collected by each center during the biological monitoring program. The comparison between the regression parameters obtained, in both cases, for each laboratory has not produced evidence of systematic differences. Furthermore, a non-parametric evaluation of the data (based on the magnitude of the differences between the results of the laboratories and the results of the reference center) shows, in most cases, similar laboratory performances in the analysis of control samples and of real samples.

Blood Chemical Analysis↗
PubMed1989

An evaluation of the results of a drug sample analysis.

An analysis of drug samples received by the National Toxicology Institute at Madrid during the period from September 1985 to May 1987 was undertaken with a view to carrying out an epidemiological assessment of drug abuse. Of 414 street drug samples, 63.5 per cent contained heroin, 12.5 per cent cocaine, 8.5 per cent amphetamine and 15.4 per cent other substances. The concentration of heroin ranged from 21 to 60 per cent in most of the samples (91.8 per cent) that contained it. Similar concentrations of cocaine were found in the samples containing that substance. Adulterants were detected in 78.8 per cent of the samples containing heroin, 59.6 per cent of the samples containing cocaine and 56 per cent of the samples containing amphetamine. The most common adulterants in the samples containing heroin were caffeine (68.4 per cent), phenobarbital (19.7 per cent), methaqualone (13.4 per cent) and procaine (13.4 per cent), while lidocaine was the most common adulterant (52 per cent) in the samples containing cocaine.

Amphetamines↗
PubMed1989

Endometrial sampling prior to hysterectomy.

Many gynecologists use routine endometrial sampling prior to hysterectomy to detect an unsuspected endometrial carcinoma. Gynecologists who formerly performed uterine curettage under anesthesia before hysterectomy now often use an outpatient endometrial sampling technique. Although safe, this procedure is complicated by discomfort, cost, and the risk of infection or uterine perforation. The purpose of this study was to determine the utility of pre-hysterectomy endometrial sampling. Between 1981-1985, 619 patients undergoing hysterectomy had preoperative endometrial sampling using Vabra aspiration, the Novak curette, or D&C. The endometrial sampling histology was compared with that in the hysterectomy specimen. There were 30 instances in which the endometrial sampling failed to identify either endometrial hyperplasia or carcinoma. In the two cases of endometrial carcinoma, D&C was the sampling method used. The findings of this study indicate that these three techniques of endometrial sampling are equal in their diagnostic capabilities. The results confirm the need for biopsy in patients with postmenopausal bleeding or with abnormal uterine bleeding at age 35 years or older. Our findings do not support routine endometrial sampling prior to hysterectomy.

Adolescent↗
PubMed1988

Comparison of sequential and fixed-structure sampling of pedigrees in complex segregation analysis of a quantitative trait.

In designing a study to demonstrate the existence of a major locus for a quantitative trait, an investigator chooses a sampling rule to ascertain pedigrees. The choice of sampling rule can significantly affect the study's power. Here, we compare two types of sampling rules for family studies: fixed-structure rules, in which the same set of relatives are sampled for each proband, and sequential rules, in which the relative or relatives to be sampled next may depend on the trait values of the individuals already observed. We compare fixed-structure and sequential sampling in the setting of extended pedigrees, a quantitative trait, and the genetic mixed model. Using computer simulation, we show that sequential sampling can increase power to detect segregation at a dominant major locus by over 60% in comparison with fixed-structure sampling. Just as important, this substantially increased power is obtained with an easily implemented sampling rule, one that might reasonably be employed in a family study of a quantitative trait.

Alleles↗