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PubMedDate not supplied

Cell preparation methods and criteria for sample adequacy. International Academy of Cytology Task Force summary. Diagnostic Cytology Towards the 21st Century: An International Expert Conference and Tutorial.

ISSUES: Cell Preparation Methods Standardized fixation and optimal staining Sampling of cervix, sampling error, homogenization of sample, subsampling Assessment of liquid-based preparations: efficacy and economic impact Training and transitional procedures before full implementation of new technologies Criteria for Sample Adequacy Clinician responsibility for collecting and providing representative sample to laboratory Collection instruments, number of slides Cellular content of samples: evidence of transformation zone (TZ) sampling, number of squamous cells present, obscuring factors Screening issues CONSENSUS POSITION The conventional cervical smear remains the standard method of cervical cancer screening but has limitations in individual test sensitivity and specificity. Sample takers should: (1) receive appropriate training in sample collection, (2) be held responsible for providing the laboratory with appropriate samples, and (3) have their performance monitored. The instruments used for sampling should collect cells from both the ectocervix and endocervix; optimally, TZ sampling, represented by the presence of endocervical or squamous metaplastic cells, should be identifiable in samples other than atrophic specimens. The adequacy of a specimen (as judged microscopically) does not guarantee that it is representative of the cervix. Each cytology report should include a comment on cellular content/adequacy of the specimen. Liquid-based preparations may overcome many of the inherent problems with the conventional cervical smear. ONGOING ISSUES: We need further data on the cost-effectiveness of making two slides from cervical specimens and/or using two samplers rather than a single one. Do we have enough information to make recommendations as to the appropriate type of sampler to be used in particular situations, such as routine screening? What is the best method of screening for/detecting endocervical glandular neoplasia? How are such terms as unsatisfactory and inadequate defined in cervical cytology classifications other than the Bethesda System? What number and types of epithelial cells should be present (visualized) in a cervical smear or liquid-based preparation for it to be considered adequate? Do we need to have evidence of TZ sampling in specimens taken during the follow-up period after treatment of squamous intraepithelial lesion or after detection of endocervical glandular neoplasia? What criteria for obscuring factors, such as blood and inflammation, should be used in assessing adequacy? Cost-benefit analyses of utilizing liquid-based preparations are needed. Should we inform women about the technical details of the test methods available or chosen by the laboratory? Are women in a position to decide which method is the most appropriate to assess their cervical scrape sample? We need to obtain more information about the properties of proprietary liquid fixative/transport media with respect to inactivation of viral pathogens, tuberculosis and other bacterial pathogens and suitability for immunobiologic and molecular tests, etc. We need to obtain more information on the use of stoichiometric stains and the limitations of Papanicolaou stain for image analysis systems. The use of liquid-based preparations for nongynecologic cytopathology and ancillary tests must be considered, including criteria for adequacy. We need to obtain more information on the time required for and best methods of training experienced cytotechnologists to become competent at assessing liquid-based cervical preparations.

Cell Biology↗
PubMed1997

Drug samples and family practice residents.

OBJECTIVE: To describe residents' knowledge, attitudes, and behaviors regarding sample medications and to determine the education provided in residency training regarding sample use. METHODS: A 6-item survey was sent to directors of US family practice residency programs. Residents of a sample of these programs were sent an anonymous, self-administered, 21-item questionnaire assessing knowledge, attitudes, and practices relating to sample use. Both surveys consisted of initial and follow-up mailings. RESULTS: The residency directors' survey was returned by 232 of the 436 residency directors (53%). Although 66% of the programs had a policy regarding samples, only 15% of the policies completely incorporated recommendations of the Society of Teachers of Family Medicine. After two mailings, 248 resident responses were received from 43 of 47 residencies (92%). Only 21% of respondents thought that they received adequate training about sample use in medical school; this number increased to 49% for residency training. Agreement with the adequate training statement was highest among respondents from residencies that had both a sample distribution policy and a pharmacist (p = 0.044). Fifty-five percent thought that samples influenced their prescribing and 70% thought that samples helped them to learn more about the sampled medication. CONCLUSIONS: Family practice residents value and use samples, although they are often unaware of the rules governing the labeling of samples. While reported distribution of samples by residents often is appropriate, education about effective sample use could be improved. Drug samples play a significant role in residency training.

Adult↗
PubMed1978

Subhourly variability of circulating third trimester maternal steroid concentrations as a source of sampling error.

Seven plasma samples from five normal third trimester pregnant women, drawn every 5 and 15 min at similar times on 2 days, 2 days apart, were measured in quadruplicate for estradiol (E2), estriol, progesterone, 16 alpha-hydroxyprogesterone, and 17 alpha-hydroxyprogesterone (17P). The mean of the 22 samples obtained from each subject for each steroid was used as a reference mean. Individual determinations were converted to percentages of the reference mean which was normalized to 0%. All pregnancies were uncomplicated, and all mean values were within the normal range for gestational age. Variability about the reference mean for single samples, however, range from a low of -80% to a high of 150%. The single sample, 95% confidence intervals for individual steroids pooled from the five subjects (110 determinations) range from +/- 36% (E2) to +/- 60% (17P). Mean percentage coefficients of variation between 5-min and 15-min sampling sequences were compared by analysis of variance. There is no significant difference between the mean percentage coefficients of variation of a 5-min as opposed to a 15-min sampling sequence for any of the hormones measured. The 95% confidence interval width around the reference mean is a function of the number of samples obtained. Because the 95% confidence interval width from 110 measurements decreases approximately as 1/ square root n with increasing sampling size, the decrement progressively diminishes. For E2, the least variable steroid, a one-sample 95% confidence interval width of +/- 36% decreases to approximately +/- 18% with four samples or approximately +/- 12% with nine samples. For 17P, the most variable steroid, a one-sample 95% confidence interval width of +/- 60% decreases to approximately +/- 30% with four samples or approximately +/- 20% with nine samples. Multiple sampling with plasma pooling is required for the accurate study of steroid concentrations in individual subjects in late pregnancy.

17-alpha-Hydroxyprogesterone↗
PubMed2005

Evaluation of enzyme-linked immunosorbent assays performed on milk and serum samples for detection of paratuberculosis in lactating dairy cows.

OBJECTIVE: To determine whether results obtained for milk and serum samples with ELISAs intended for diagnosis of paratuberculosis in dairy cows were comparable to results obtained by means of mycobacterial culture of fecal samples. DESIGN: Cross-sectional study. ANIMALS: 689 lactating dairy cows in 9 Ontario herds. PROCEDURE: Milk, serum, and fecal samples were obtained from all cows. Fecal samples were submitted for mycobacterial culture. Serum samples were tested with a commercially available ELISA for antibodies against Mycobacterium paratuberculosis, and preserved milk samples were tested with an indirect ELISA for antibodies against M paratuberculosis. RESULTS: Results were positive for 130 of the 689 (18.9%) serum samples, 77 of the 689 (11.1%) milk samples, and 72 of the 689 (10.4%) fecal samples. The level of agreement between results for milk and serum samples was only moderate. Proportions of positive results for serum and fecal samples were significantly different, but proportions of positive results for milk and fecal samples were not significantly different. In addition, results for milk samples had a higher level of agreement with results of mycobacterial culture than did results for serum samples. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that the indirect ELISA used on milk samples may be a convenient method of detecting paratuberculosis in dairy herds.

Animals↗
PubMed1990

Effect of milk sample delivery methods and arrival conditions on bacterial contamination rates.

A cross sectional study was performed of factors believed to contribute to the contamination of bovine milk sample cultures submitted to the Ithaca Regional Laboratory of the Quality Milk Promotion Services/New York State Mastitis Control. Of 871 samples entered in the study, 137 (15.7%) were contaminated. There were interactions between the sample source (veterinarian vs dairyman), delivery method, and time between sample collection and arrival at the laboratory. If only those samples collected and hand delivered by the dairyman within 1 day of collection were compared to a like subset of samples collected and hand delivered by veterinarians, no statistically significant differences in milk sample contamination rate (MSCR) were found. Samples were delivered to the laboratory by hand, US Postal Service, United Parcel Service, via the New York State College of Veterinary Medicine Diagnostic Laboratory, or Northeast Dairy Herd Improvement Association Courier. The MSCR was only 7.6% for hand delivered samples, while 26% of Postal Service samples were contaminated. These rates differed significantly from other delivery methods (P less than 0.0001). The USPS samples arrived a longer time after sampling than did samples sent by other routes, and time had a significant effect on MSCR (0 to 1 day, 8.9%; greater than 1 day, 25.9%; P less than 0.01). Samples packaged with ice packs sent by routes other than the Postal Service had a lower MSCR than those not packaged with ice packs, but ice packs did not reduce the MSCR for samples sent by the Postal Service.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1996

[Detection of Mycobacterium tuberculosis in clinical specimens other than sputum by the Mycobacterium Tuberculosis Direct Test (MTD)--assessment of sample preparation methods and clinical evaluation].

The Gen-Probe Amplified Mycobacterium Tuberculosis Direct Test (MTD) has been widely used as a rapid test for the identification of Mycobacterium tuberculosis complex in clinical samples, and several research groups have verified its clinical usefulness. However, most of the specimens they tested were sputum, and there have been few reports on other specimens. In particular, there have been no reports on assessments of methods of preparing samples other than sputum for the MTD. We assessed methods of preparing samples other than sputum and the influence of a local anesthetic and an anticoagulant that may be present in samples, and also evaluated the MTD as a means of detecting M. tuberculosis in pleural fluid, bronchial lavage cerebrospinal fluid, urine and ascitic fluid. 1. Assessment of three sample preparation methods, i.e., the NALC-NaOH method GuSCN-Diatom nucleic acid extraction method, and the ultrasonication method, revealed that the combination of the NALC-NaOH method and the ultrasonication method, widely used to prepare sputum samples, is also a valid method of preparing other samples. 2. The local anesthetic and the anticoagulant used clinically and remained in specimens did not affect the results of the MTD. 3. Seven (36.8%) of 19 pleural fluid samples from patients diagnosed as tuberculous pleurisy were positive of M. tuberculosis by the MTD, while five (27.8%) of 18 pleural fluid samples cultured for bacteria were positive for M. tuberculosis complex. None of the 20 pleural fluid samples from patients diagnosed as non-tuberculous pleurisy were positive for M. tuberculosis complex either by MTD or culture. 4. Eight (32.0%) of 25 bronchial lavage samples from patients diagnosed as pulmonary tuberculosis were positive for M. tuberculosis complex by the MTD, while 3 (12.0%) were positive by culture. None of the 18 bronchial lavage samples from patients diagnosed as non-tuberculous disease were positive for M. tuberculosis complex either by the MTD or culture. Based on these results, it is concluded that the MTD is a very useful method of detecting M. tuberculosis in clinical samples other than sputum because it is more sensitive than culture on Ogawa's egg medium in detecting M. tuberculosis complex in pleural fluid samples, bronchial lavage samples, and so on, with the same preparation method as used for sputum.

Bacteriological Techniques↗
PubMedDate not supplied

[Detection of rubella antibodies in blood samples collected on filter paper].

Congenital rubella syndrome (CRS) could be prevented if young women knew their immune status before pregnancy, contributing in this way to decrease the birth morbidity rate due to CRS among the children. Our objective was to optimize the detection of rubella virus-antibodies by HAI, using an easier and safer method to collect samples of big populations. One hundred specimens, obtained from patients in a pediatric hospital and pregnant women in an institute of Virology were used for this work. Venous blood was drawn and collected in a test tube, and few drops were spotted onto filter paper circles. These samples were kept in envelopes and stored at room temperature until analysis. Seventy two percent of dried blood samples had titers identical to those of the corresponding serum samples, and 28% dried blood samples showed 1 dilution of difference. Storage of dried blood at room temperature for 30 days did not affect the HAI titers. Up to 60 days post attainment, 59% dried blood samples had identical titers to those of the corresponding serum samples, and 41% dried blood samples showed one dilution of difference. At 100 days of storage 51% dried blood samples had identical titers to those of the corresponding serum samples, 38% dried blood samples showed 1 dilution of difference and 11% and more than 1 dilution of difference. In conclusion, dried blood on filter paper is an easier method to transport and store blood samples for the determination of rubella virus immunity, for as long as 30 days. It could be used for large-scale epidemiological studies. The sensitivity and specificity of HAI performed on dried blood samples was 100%. Only 0.25 ml of whole blood is needed and the samples are stable at room temperature, without air or sterile conditioning. The proposed methodology is a practical approach to collect, transport and store blood samples. Moreover the blood dried on paper spots can be placed in a plastic bag and mailed to a reference laboratory. This is an appropriate alternative method for serological screenings in developing countries.

Adolescent↗
PubMed2006

[Relationship between sample size and variation of means for personal noise exposure in weaving workers].

OBJECTIVE: To explore the relationship between sample size and variance of means for personal noise exposure in weaving workers as to contributing evidence for establishing personal noise exposure measurement guideline. METHODS: A personal noise exposure measurement database from a group of weaving workers was used in the randomized re-sampling data analysis. The sampling cases were one number selecting from one to fifteen at each randomized re-sampling procedure. The randomized re-sampling was one thousand times from original personal noise exposure measurement database to get one thousands of re-sampling database. One thousands of L(Aeq.8 h) mean were calculated by re-sampling databases. The variation of randomized re-sampling means was analyzed for different re-sampling numbers. RESULTS: The change for narrow trend of maximum, minimum, 95 percent number, 5 percent number of L(Aeq.8 h) mean was faster when randomized re-sampling number was smaller in variation vs randomized re-sampling number curve analysis. After that, the change for narrow trend of L(Aeq.8 h) mean was smooth for increasing the randomized re-sampling numbers. The 95% - 5% of L(Aeq.8 h) mean was about half for randomized re-sampling four cases (3.30 dB) vs one case (7.40 dB), and about one third for seven cases (2.44 dB), and about one fourth for eleven cases (1.85 dB). CONCLUSION: The sample size in personal noise exposure measurement guideline could be selected from four to eleven.

Humans↗
PubMed1994

Optimal sampling theory: effect of error in a nominal parameter value on bias and precision of parameter estimation.

The authors examined the robustness of optimal sampling theory in estimating the parameter values of two different populations of patients receiving a constant rate, half-hour intravenous infusion of theophylline. One population consisted of smokers; the other included nonsmokers. The smoking population was predicted to have a serum clearance approximately 50% greater than the nonsmokers because of an induction of the cytochrome P450 system. After an initial study to provide both patient-specific and population mean parameter values, optimal sampling strategies that were derived from each population (seven sample split designs) and the patient's seven sample and four sample design were determined. A second study was performed with an overall sampling strategy that was superset of all the above strategies. The analysis of all samples served as the reference for the parameter values. Bias and precision of the values determined with each of the optimal sampling sets (seven sample sets based on the "correct" and "wrong" populations, the patient's seven and four sample sets) were determined relative to these reference values. Irrespective of the sample set used for analysis, unbiased and precise parameter estimates, particularly of hybrid parameters were provided. With the patient's four sample set, Vss was significantly biased, but the value of (2.2%) was clinically insignificant. The authors conclude that optimal sampling theory, as implemented in this study, provides robust estimates of important pharmacokinetic parameter values, even when errors of 50% are present in the clearance of the population used to calculate the optimal sampling design.

Adolescent↗
PubMed2005

Detection of mosaicism for primary trisomies in prenatal samples by QF-PCR and karyotype analysis.

OBJECTIVES: QF-PCR can be used to rapidly diagnose primary trisomy in prenatal samples. Our objectives were to estimate the prevalence of primary trisomy mosaicism for chromosomes 13, 18 or 21 in a cohort of prenatal samples, and to compare and contrast the detection of this mosaicism using both QF-PCR and karyotype analysis. METHODS: Data was collated from all prenatal samples displaying mosaicism for a primary trisomy between June 2000 and March 2004. Levels of mosaicism were estimated and samples were categorised according to the cell population in which the mosaicism was detected. RESULTS: In a total of 8983 samples, 18 samples (0.20%) displaying mosaicism were detected, including trisomy 13 (three samples), trisomy 18 (seven samples), trisomy 21 (seven samples) and mosaic triploidy (one sample). This included 7 amniotic fluid and 11 chorionic villus samples. Mosaicism was detected by QF-PCR in 12 samples and by karyotype analysis in 8 samples. CONCLUSIONS: QF-PCR can detect mosaicism when the abnormal cell line contributes at least 15% of the whole sample. Use of both karyotype and QF-PCR analysis leads to the detection of more cases of mosaicism than either test alone.

Adult↗
PubMed2004

The external validity of results derived from ecstasy users recruited using purposive sampling strategies.

This study sought to compare the patterns and correlates of 'recent' and 'regular' ecstasy use estimated on the basis of two datasets generated in 2001 in New South Wales, Australia, from a probability and a non-probability sample. The first was the National Drug Strategy Household Survey (NDSHS), a multistage probability sample of the general population; and the second was the Illicit Drug Reporting System (IDRS) Party Drugs Module, for which regular ecstasy users were recruited using purposive sampling strategies. NDSHS recent ecstasy users (any use in the preceding 12 months) were compared on a range of demographic and drug use variables to NDSHS regular ecstasy users (at least monthly use in the preceding 12 months) and purposively sampled regular ecstasy users (at least monthly use in the preceding 6 months). The demographic characteristics of the three samples were consistent. Among all three, the mean age was approximately 25 years, and a majority (60%) of subjects were male, relatively well-educated, and currently employed or studying. Patterns of ecstasy use were similar among the three samples, although compared to recent users, regular users were likely to report more frequent use of ecstasy. All samples were characterised by extensive polydrug use, although the two samples of regular ecstasy users reported higher rates of other illicit drug use than the sample of recent users. The similarities between the demographic and drug use characteristics of the samples are striking, and suggest that, at least in NSW, purposive sampling that seeks to draw from a wide cross-section of users and to sample a relatively large number of individuals, can give rise to samples of ecstasy users that may be considered sufficiently representative to reasonably warrant the drawing of inferences relating to the entire population. These findings may partially offset concerns that purposive samples of ecstasy users are likely to remain a primary source of ecstasy-related information.

Adolescent↗
PubMed1994

Detection of measles virus from clinical samples using the polymerase chain reaction.

OBJECTIVE: To evaluate the usefulness of the polymerase chain reaction to detect the measles virus sequence using clinical samples. DESIGN: Centers for Disease Control and Prevention case definition of measles with or without IgM serology as a standard. SETTING: A laboratory in the Department of Pediatrics of the Hokkaido University Hospital, Sapporo, Japan. PATIENTS: Thirty-two serum samples, 16 throat swab samples, and nine cerebrospinal fluid samples from 32 patients with measles, including four patients with central nervous system involvement, and one serum sample and two throat swab samples from two patients with modified courses of measles were obtained. Ten serum samples, 10 throat swab samples, and 10 cerebrospinal fluid samples were obtained from patients without apparent measles infection as negative controls. MEASUREMENTS AND MAIN RESULTS: Sensitivity and specificity were comparable with those as obtained by culture or other methods reported in the literature. The polymerase chain reaction was positive in 24 (75.0%) of 32 by serum samples and in 13 (81.3%) of 16 by throat swab samples from the patients with measles, in contrast to none within the negative control group. In three of the four patients with central nervous system involvement, the measles virus sequence was detected in cerebrospinal fluid samples obtained within 1 day following the onset of the manifestations. All three samples from the patients with modified measles yielded positive results. CONCLUSIONS: The polymerase chain reaction can be used with sufficient sensitivity and specificity to detect the measles virus sequence using clinical samples. Transient and direct invasion of the central nervous system by this virus at the initial stage of the central nervous system involvement was strongly suggested.

Adolescent↗
PubMed2003

Total RNA yield and microarray gene expression profiles from fine-needle aspiration biopsy and core-needle biopsy samples of breast carcinoma.

BACKGROUND: Gene expression profiling should be applicable to needle biopsy samples if microarray technology is to become practically useful for clinical research or management of breast carcinoma. This study compared gene expression profiles derived from fine-needle aspiration biopsy (FNAB) and from core needle biopsy (CBX). METHODS: Total RNA was extracted from single FNAB and CBX samples. Corresponding pairs of FNAB and CBX were analyzed for similarity of gene expression profiles using cDNA microarrays that contain 30721 human sequences. A subset of genes that distinguished CBX samples from FNAB samples was evaluated in a larger group of needle biopsy samples and in a published genomic database derived from 78 sporadic breast carcinomas with known clinical outcome. RESULTS: Sixty-eight patients with newly diagnosed breast carcinoma were included in the current study. Sixty-five patients underwent FNAB (17 had both FNAB and CBX) and 3 underwent CBX only. Extracted RNA was of suitable quality for hybridization in 46 (71%) FNABs and 15 (75%) CBXs. Total RNA yield in those samples was similar for single-pass FNAB (mean = 3.6 microg and median = 2.2 microg; n = 46) and CBX (mean = 2.8 microg and median = 2.0 microg; n = 15), with 1 microg or more of total RNA in all cases. Transcriptional profiling was performed successfully in all cases when it was attempted, in a total of 50 samples (38 FNABs and 12 CBXs), including matched FNAB and CBX samples from 10 patients. There were differences in gene expression profiles in 10 matched FNAB and CBX sample pairs. Genes that were expressed differently in CBX samples, compared with FNAB samples, were recognized as being predominantly from the endothelium, fibroblasts, myofibroblasts or smooth muscle, and histiocytes. Corresponding microscopic cell counts from FNABs demonstrated means of 80% tumor cells, 15% lymphocytes, and 5% stromal cells, whereas CBXs contained 50% tumor cells, 20% lymphocytes, and 30% stromal cells. Considering that CBXs are approximately six-fold richer in nonlymphoid stromal cells than FNABs and that CBXs differentially express a set of recognized stromal genes, the authors used these biopsies to define a transcriptional profile of breast carcinoma stroma. A set of 120 genes differentially expressed in CBXs was assessed independently in a published breast carcinoma genomic database to classify breast carcinomas based on stromal gene expression. Subgroups of tumors with low or high stromal signal were identified, but there was no correlation with the development of systemic metastases within 5 years. CONCLUSIONS: Both FNAB and CBX yield a similar quality and quantity of total RNA and are suitable for cDNA microarray analyses in approximately 70-75% of single-pass samples. Transcriptional profiles from FNAB and CBX of the same tumor generally are similar and are driven by the tumor cell population. The authors concluded that each technique has relative advantages. The FNABs provide transcriptional profiles that are a purer representation of the tumor cell population, whereas transcriptional profiles from CBXs include more representation from nonlymphoid stromal elements. Selection of the preferred needle biopsy sampling technique for genomic studies of breast carcinomas should depend on whether variable stromal gene expression is desirable in the samples.

Adult↗
PubMed2002

Detection of fetal cells in intrauterine lavage samples collected in the first trimester of pregnancy.

OBJECTIVES: The aim of the present study was first to evaluate the presence of fetal cells in transcervical cell (TCC) samples collected by intrauterine lavage in the first trimester of pregnancy, and then to compare different methods for the detection of these cells. METHODS: TCC samples were collected by intrauterine lavage before termination of pregnancy (TOP) from 81 pregnant women between 7 and 12 weeks of gestation. Samples of placental tissue were collected from each patient at TOP, whereas maternal peripheral blood samples were obtained in 57 cases. DNA extracted from 81 lavage and the corresponding placental samples was amplified by a polymerase chain reaction (PCR) assay using primers for SRY and HUMARA genes. All 81 lavage samples were also analysed by fluorescent in situ hybridisation (FISH) using direct-labelled probes for X chromosome alpha-satellite (DXZ1, Xp11.1-q11.1) and Y chromosome alpha-satellite (DYZ3, Yp11.1-q11.1) regions. In 57 cases, a quantitative fluorescent (QF) PCR assay, involving the use of two small tandem repeat (STR) markers (D21S11, D21S14.11) specific to chromosome 21 was employed to analyse DNA extracted from placental tissue, lavage and maternal blood samples. RESULTS: PCR analysis revealed that 40/81 placental samples were from male pregnancies. Correct sexing was achieved with the PCR technique in 30/40 (75%) lavage samples retrieved from pregnant women with male conceptuses and in all 41 (100%) samples collected from pregnancies with female fetuses. With the FISH analysis, nuclei bearing X and Y signals were observed in 32/40 cases (80%) from known male pregnancies, the rate of fetal cells ranging between 2% and 95%, whereas nuclei showing X and Y signals were not detected in any of the 41 lavage samples from known female pregnancies. Paternal peaks were present in 30/57 (52.6%) lavage samples tested by QF-PCR. CONCLUSION: The results suggest that fetal cells can be found, at a significant rate, in a very high proportion of intrauterine lavage samples. Therefore, this sampling technique can be regarded as a promising tool towards minimally invasive prenatal diagnosis. The FISH and PCR methods showed a similar efficiency in detecting fetal cells.

Adult↗
PubMed1995

Distribution of smokers by stage in three representative samples.

OBJECTIVES: A key variable for the design of individual and public health interventions for smoking cessation is Stage of Change, a variable which employs past behavior and behavioral intention to characterize an individual's readiness to change. Reactively recruited samples distort estimates of the stage distribution in the population because such samples attract a disproportionate number of late-stage participants. Three representative samples are described which provide accurate estimates of the stage distribution in the population. These samples are of adequate size to permit within-sample comparisons with respect to sex, age, Hispanic or non-Hispanic origin, race, and education level. The implications of using stage distribution as a tool for planning intervention is discussed. METHOD: The first sample of 4,144 smokers was from the state of Rhode Island and involved a random-digit-dial survey. The second sample of 9,534 smokers was from the state of California and involved a stratified random-digit-dial survey. The third sample of 4,785 smokers was from a total of 114 worksites located in four different geographic locations. RESULTS: The stage distributions were approximately identical across the three samples, with approximately 40% of the sample in Precontemplation, 40% in Contemplation, and 20% in Preparation. The stage distribution was generally stable across age groups with the exception of the 65 years and older group. Education level did affect the stage distribution with the proportion of the sample in Precontemplation decreasing as education level increased. In all three samples, minor differences in stage distribution were related to Hispanic origin and race, but the pattern was not consistent across the samples. CONCLUSIONS: The pattern of stage distribution has important implications for the design of interventions. Existing interventions are most appropriate for the Preparation stage, but the majority of the three samples were in the first two stages, resulting in a likely mismatch between the smoker and the intervention. The stability of distribution across age suggests that interventions that are appropriately matched to stage can be applied across all age groups. The differences found with respect to education, Hispanic origin, and race can serve as a guide to the tailoring of intervention materials.

Adult↗
PubMed1987

Sampling, log binning, fitting, and plotting durations of open and shut intervals from single channels and the effects of noise.

(1) Analysis of the durations of open and shut intervals measured from single channels currents provides a means to investigate the mechanisms of channel gating. Durations of open and shut intervals are conveniently measured from single channel data by using a threshold level to indicate transitions between open and shut states. This paper presents a detailed characterization of sampling, binning, and noise errors associated with 50% threshold analysis, provides criteria to reduce these errors, methods to correct for them, and presents an efficient means of data handling for binning and plotting interval durations. (2) Measuring interval durations by sampling at a fixed rate introduces two types of errors, (a) the number of intervals of a given measured duration are increased (promoted) over that expected in the absence of sampling, producing a sampling promotion error, (b) sampling decreases the total fraction of true intervals that are detected, producing a sampling detection error. Sampling errors can be reduced to negligible levels if the actual or effective (after interpolation) sampling period is less than 10-20% of both the dead time and fastest time constant in the distribution of intervals. Dead time is given by the duration of a true interval that has a filtered amplitude equal to 50% of the true amplitude. (3) Methods are presented to correct for sampling promotion error during least squares and maximum likelihood fitting. Sampling detection error is more difficult to correct, but an empirical description of the sampling detection error can be used to calculate the effective fraction of detected events with sampling. (4) Noise in the single channel current record can produce two types of error. (a) If noise peaks in the absence of channel activity exceed the threshold for detection, then false channel events of brief duration are produced. Sufficient filtering will prevent this type of error. (b) Noise can also increase the total fraction of true intervals that are detected, producing a noise detection error. Increased filtering over that required to prevent false events is not necessarily the best method for reducing noise detection error, as increased filtering can prevent detection of the faster exponential components. (5) Noise detection error can be reduced in two ways: (a) an empirical description of the noise detection error can be used to calculate the effective fraction of detected events in the presence of noise. (b) The sampling period can be selected so that the sampling detection error cancels the noise detection error.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed2006

Detection of legionella species in clinical samples: Comparison of polymerase chain reaction and urinary antigen detection kits.

BACKGROUND: Recently, two excellent methods have been used for the diagnosis of Legionnaires' disease: urinary antigen detection and PCR. The purpose of the present study is to analyze and evaluate the sensitivity and specificity of three different urinary antigen detection kits as well as PCR. MATERIALS AND METHODS: A total of 148 samples were collected from 33 patients between 1993 and 2004. These consisted of 73 urine samples obtained from 33 patients, 57 serum samples provided by 29 patients, and 18 respiratory tract specimens from 13 patients. Three commercially available kits were used to detect urinary antigen. For the 5S PCR reaction, primers L5SL2 and L5SR84 were used. RESULTS: Positive results were shown in all patients' urine (representing 79.5% of total samples) using the Binax EIA kit, in 93.9% patients (representing 75.3% samples) using the Binax NOW immunochromatographic kit, and in 90.9% (representing 72.6% samples) using the Biotest EIA kit. Urine samples from 12.1% patients (representing 6.8% of total samples), serum samples from 41.4% patients (representing 35.1% of total samples), and respiratory samples from 84.6% patients (representing 88.9% of total samples) showed positive results with PCR. CONCLUSION: In testing urine of legionellosis patients, it was suggested that three kits were all valuable tools for diagnosis of legionellosis. Since over one-third of patients' serum samples and most respiratory specimens showed positive results with PCR, the addition of PCR for testing of these samples might be useful, particularly in cases of culture negative and serum antibody negative patients.

Adult↗
PubMed2004

The effect of blood sampling method on indicators of physiological stress in reindeer (Rangifer tarandus tarandus).

The effects of manual blood sampling and remote blood sampling using automatic blood sampling equipment (ABSE) on plasma cortisol and catecholamine concentrations were studied on eight adult female reindeer (Rangifer tarandus tarandus). Contemporary body temperatures and heart rates were also recorded to determine their utility as other possible stress indicators. The animals were blood sampled once every hour with ABSE on 9-10 May and then by manual blood sampling on 13-14 May. Animals were also fitted with equipment to record heart rate and body temperature. Heart rate and body temperature were also recorded continuously without blood sampling on 17-18 May in undisturbed control conditions. Plasma cortisol concentrations were five-to-six fold greater during manual blood sampling compared to sampling with ABSE (F(1,3) = 13.34, P < 0.05). Plasma noradrenaline concentrations were significantly higher (F(1,3) = 22.98, P < 0.05) during manual blood sampling compared to sampling with ABSE, whereas plasma adrenaline concentrations did not differ. Heart rate was higher during manual blood sampling compared to control values. Body temperature was significantly higher during manual sampling compared to values recorded without blood sampling (F(1,4)= 31.65, P < 0.01). In conclusion, plasma cortisol concentration provides an excellent indicator of handling stress in reindeer. The use of ABSE for blood sampling enables measurements of plasma cortisol levels close to basal concentrations that may be used for reference values in studies where indicators of physiological stress are required.

Animals↗