Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Sampling”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 793 records · Page 44Linked to original sources
PubMed2001

Changes in sample collection and analytical techniques and effects on retrospective comparability of low-level concentrations of trace elements in ground water.

Ground-water sampling techniques were modified to reduce random low-level contamination during collection of filtered water samples for determination of trace-element concentrations. The modified sampling techniques were first used in New Jersey by the US Geological Survey in 1994 along with inductively coupled plasma-mass spectrometry (ICP-MS) analysis to determine the concentrations of 18 trace elements at the one microgram-per-liter (microg/L) level in the oxic water of the unconfined sand and gravel Kirkwood-Cohansey aquifer system. The revised technique tested included a combination of the following: collection of samples (1) with flow rates of about 2 L per minute, (2) through acid-washed single-use disposable tubing and (3) a single-use disposable 0.45-microm pore size capsule filter, (4) contained within portable glove boxes, (5) in a dedicated clean sampling van, (6) only after turbidity stabilized at values less than 2 nephelometric turbidity units (NTU), when possible. Quality-assurance data, obtained from equipment blanks and split samples, indicated that trace element concentrations, with the exception of iron, chromium, aluminum, and zinc, measured in the samples collected in 1994 were not subject to random contamination at 1 microg/L. Results from samples collected in 1994 were compared to those from samples collected in 1991 from the same 12 PVC-cased observation wells using the available sampling and analytical techniques at that time. Concentrations of copper, lead, manganese and zinc were statistically significantly lower in samples collected in 1994 than in 1991. Sampling techniques used in 1994 likely provided trace-element data that represented concentrations in the aquifer with less bias than data from 1991 when samples were collected without the same degree of attention to sample handling.

Environmental Monitoring↗
PubMed2001

A soil sampling strategy for mapping trace element concentrations in a test area.

A sampling strategy, based on previous knowledge of a test area, was compared with a Reference Sampling in the frame of the EU-funded CEEM project. The aim was a comparison of sampling strategies for the drafting of concentration maps for a set of trace elements (Cd, Pb, Cu and Zn), with three-dimension information that can be used for risk assessment. The main constraint was that only 15 soil samples were to be analysed. The test area (in Dornach, Switzerland) included different soil types and land uses (forest, arable land and permanent grasslands). The sampling strategy proposed defined strata on the basis of land use, then applying a systematic regular sampling within each stratum. A composite sample was formed from each individual sample. In forests, H and Ah horizons were taken separately. In arable lands, a depth within the ploughed layer (0-15 cm) was analysed. In grasslands, samples were taken at two depths (0-10 and 10-20 cm) to provide information on the vertical variability. The comparison of the results obtained with those derived from the Reference Sampling allowed us to estimate if the information obtained from the proposed sampling strategy was sufficiently representative for an assessment of the level of elements considered. It was concluded that recommendations on sampling strategy depend on the interaction pattern of the element. In this case, for mobile trace elements, such as Cd, the information derived from sampling of two soil layers was not as important as that for the rest of metals studied that accumulated in the upper layer. If the H horizons in forests was not considered this led to unreliable predictions of the concentration levels, since the concentrations in H and Ah horizons differed irrespective of whether they were expressed in mg kg(-1) (the H horizon was enriched in those trace elements, except for Cd) and in mg m(-2) (the low bulk density of the H horizon led to a lower trace element level than in Ah horizon). Finally, in undisturbed systems such as grasslands, sampling 0-10 cm instead of 0-20 cm is recommended to prevent dilution of the concentration of trace elements.

Agriculture↗
PubMedDate not supplied

[Quality and selection of samples of bronchoalveolar lavage (BAL) in diffuse pneumopathies].

Bronchoalveolar lavage (BAL) samples used to study immune or inflammatory response in interstitial lung disease must be representative of the lower respiratory tract. Thus, the selection of suitable samples must be part of routine practice. To assess the incidence of unsuitable BAL samples used for cytology and to determine the relation between parameters related to underlying disease and the quality of samples. One hundred sixty-one patients were enrolled. Seventy-two were HIV positive and had diffuse pulmonary infiltrates, 34 had idiopathic pulmonary fibrosis (IPF), 10 had sarcoidosis, 10 had hypersensitivity pneumonitis, 19 had interstitial lung disease and collagen diseases and 2 had pulmonary eosinophilia. Fourteen individuals formed the control group. The quality study was carried out by staining the BAL samples following a modified Wright-Giemsa technique and evaluating the samples by the selection criteria described by Chamberlain and colleagues (1987). We identified unsuitable samples from 53% of the HIV positive patients, from 35% of the IPF patients and from 21% of the interstitial lung disease patients with associated connective tissue disease. In the other groups, all samples were suitable for analysis. Intolerance of BAL with decreasing percentage of fluid recovered was significantly associated with sample quality, particularly in the IPF group. The cytology results that invalidated the samples differed by group. In all groups, unsuitable specimens had low cell counts. The finding or not of evidence of associated infection in HIV-infected patients, on the other hand, did not appear to determine sample quality in and of itself, although it did in samples related to other entities. We can predict that a high rate of unsuitable BAL samples will come mainly from patients with diffuse lung disease associated to HIV infection, IPF and interstitial lung disease with associated connective tissue disease. Tolerance to the technique influences quality of the specimen obtained and, therefore, should be taken into account in interpreting the findings of cytology. The criteria applied by the various teams using BAL should be unified, and it should be determined whether the exclusion of inappropriate samples affects the final composition of study groups.

Bronchoalveolar Lavage↗
PubMedDate not supplied

Sampling design, response rates, and analysis weights for the National Human Exposure Assessment Survey (NHEXAS) in EPA region 5.

For the Phase I field test of the National Human Exposure Assessment Survey (NHEXAS) in U.S. Environmental Protection Agency (EPA) Region 5, this paper presents the survey sampling design, the response rates achieved, and the sample weighting procedure implemented to compensate for unit nonresponse. To enable statistically defensible inferences to the entire region, a sample of about 250 members of the household population in EPA Region 5 was selected using a stratified multistage probability-based survey sampling design. Sample selection proceeded in four nested stages: (1) sample counties; (2) area segments based on Census blocks within sample counties; (3) housing units (HUs) within sample segments; and (4) individual participants within sample households. Each fourth-stage sample member was asked to participate in 6 days of exposure monitoring. A subsample of participants was asked to participate in two rounds of longitudinal follow-up data collection. Approximately 70% of all sample households participated in household screening interviews in which rosters of household members were developed. Over 70% of the sample subjects selected from these households completed the Baseline Questionnaire regarding their demographic characteristics and potential for exposures. And, over 75% of these sample members went on to complete at least the core environmental monitoring, including personal exposures to volatile organic compounds (VOCs) and tap water concentrations of metals. The sample weighting procedures used the data collected in the screening interviews for all household members to fit logistic models for nonresponse in the later phases of the study. Moreover, the statistical analysis weights were poststratified to 1994 State population projections obtained from the Bureau of the Census to ensure consistency with other statistics for the Region.

Adolescent↗
PubMed2003

Effects of liquid conductivity differences on multi-component sample injection, pumping and stacking in microfluidic chips.

As an increasing number of processes are being integrated into Lab-on-a-chip devices, there is an increasing need for flexible and accurate sample manipulation techniques for effective transport and separation. Conductivity differences between running buffer and analyte samples can arise as a product of on-chip processing, or by design. The two situations studied here are sample pumping (where bulk transport is increased and separation of charged analytes is delayed using a relatively high conductivity sample), and sample stacking (where bulk transport is decreased and separation of charged analytes is expedited using a relatively low conductivity sample). A recently developed dynamic loading method for on-chip sample injection in a straight-cross channel configuration is applied here to both pumping and stacking cases. A key characteristic of the dynamic loading method is the ability to inject samples of high concentration density and uniformity of any length. By employing the conductivity differences alone, the effectiveness of either sample transport or sample separation are shown to improve over the uniform conductivity case. Then it is demonstrated that increasing the sample length, through dynamic loading, greatly increases the effectiveness of sample pumping, evidenced in an eight-fold increase in peak height as well as a decrease in total sample length at a downstream detector. Dynamic loading in the sample stacking case was shown to also increase peak intensity height (three-fold) in rapid separations. These results demonstrate that the dynamic loading technique, used in conjunction with strategic conductivity differences, significantly extends the capabilities of microfluidic chips.

Journal Article↗
PubMed1985

Residential formaldehyde sampling--current and recommended practices.

The usefulness of test results in assessing the health hazard potential of residential formaldehyde exposures depends in great measure on the accuracy and reliability of sampling/analysis methods employed, the protocol used in collecting samples, sampling objectives, and an understanding of residential formaldehyde dynamics and their relationship to environmental variables. Active sampling and analysis methods including detector tubes, the impinger/chromotropic acid method, the impinger/pararosaniline method, and the CEA continuous monitor are reviewed as to advantages and limitations for residential sampling. Passive dosimeter methods including the Dupont Pro-Tec Badge, 3M Monitor, Air Quality Research, Inc. Passive Formaldehyde Kit, and Envirotech, Inc. Dosimeter are also reviewed. Sampling considerations for one-time formaldehyde sampling using the impinger/chromotropic acid method are discussed in detail, including pre-sampling closure of residences, maintenance of a standard indoor temperature both before and during sampling, the undesirability of sampling during cold, dry winter weather, sample number, sampling location, height and duration, environmental measurements during sampling, source identification and sample storage. A model formaldehyde sampling protocol based on the impinger/chromotropic acid method is described.

Air Pollutants↗
PubMed1989

Investigation of charcoal cloth as a sorbent for integrated sampling of solvent vapors in mixed-expired breath using a new stainless steel sampler.

A stainless steel device for integrated sampling of solvents present in mixed-expired breath is described. During sampling, the subject inhales breathing air through commercial charcoal inhalation canisters. Exhaled breath is sampled from the mainstream using 45-mm wafers of charcoal cloth or from the sidestream on other sorbents. The device concentrates trace contaminants present in large volumes of breath. The charcoal cloth sorbent was evaluated for sampling and analysis of m-xylene and 1,1,1-trichloroethane under simulated physiological conditions. These samples were collected from atmospheres of either analyte generated at 35 degrees-40 degrees C and 80%-90% relative humidity to simulate an exhaled breath sample matrix. Concentrations sampled ranged from 2.2 to 190 mg/m3 for 1,1,1-trichloroethane and from 0.44 to 35.6 mg/m3 for m-xylene. Volumes sampled ranged from 10 to 50 L. The m-xylene samples were collected using a 3-wafer front and a 2-wafer backup bed of charcoal cloth; 1,1,1-trichloroethane samples were collected using a 10-wafer front and a 1-wafer backup bed. All samples were desorbed in carbon disulfide and analyzed via gas chromatography using a flame ionization detector. The volume of desorption solvent ranged from 1.7 to 2.5 mL per wafer of cloth. The quantitation limit is estimated to be 2.0 micrograms/L for 1,1,1-trichloroethane and 0.4 micrograms/L m-xylene for a 50-L sample. At least 80% recovery was obtained for m-xylene or 1,1,1-trichloroethane samples stored from 1 to 14 days after collection, if the samples were refrigerated at 0 degrees C after an initial 7-day storage period at room temperature. The recovery of hexane, 1-hexene, ethyl acetate, isopropanol, methylene chloride, and methyl isobutyl ketone from the charcoal cloth also has been investigated and is reported. With the exception of isopropanol, all analytes were recovered quantitatively from the charcoal cloth by desorption with carbon disulfide following storage for 1 to 17 days at ambient temperatures.

Breath Tests↗
PubMed2006

Collection, validation and generation of bitumen fumes for inhalation studies in rats Part 1: Workplace samples and validation criteria.

OBJECTIVES: Undertaking a chronic inhalation study on bitumen fume presents a challenge in terms of generating large amounts of representative fume. The objective of the study described in this and the following contributions was to collect sufficient fume and develop a laboratory-generated exposure atmosphere that resembles, as closely as possible, personal exposures seen in workers during road paving operations, for use in chronic inhalation toxicity studies in rats. METHODS: To achieve this goal, atmospheric workplace samples were collected at road paving work sites both by Shell Global Solutions, Int. (Shell) and by the 'Berufsgenossenschaftliches Institut für Arbeitssicherheit' (BIA, Germany) and compared with bitumen fume condensate samples collected from the head space of hot bitumen storage tanks. Part 1 describes the collection and analysis of personal and static workplace samples. Different sampling methods were also used to allow a comparison of the standard German sampling method with the most common industry method used. Samples were analyzed by Shell, BIA and by the Fraunhofer Institute of Toxicology and Experimental Medicine (Fh-ITEM, Germany) using different methods. Parameters determined were: total particulate matter (TPM), benzene soluble matter (BSM), semi-volatiles (SV), total organic matter (TOM), boiling point distribution (BPD), polycyclic aromatic hydrocarbons (PAHs) and UV fluorescence (UVF). RESULTS: The BPD of personal and static samples had almost identical start and end points, but static samples show a tendency towards an increase in amounts of higher boiling point compounds. Personal samples generally show higher PAH concentrations than comparable static samples. The results of the analysis of personal workplace samples were used to establish validation/acceptance criteria for the bitumen fume condensate sampled from storage tanks for the inhalation study, which is described in a further publication. CONCLUSIONS: The criteria involve a range of parameters that can be analyzed in both workplace samples and samples of tank fume condensate: BPD, UVF and content of individual PAHs were selected as parameters.

Air Pollutants, Occupational↗
PubMed1998

Comparison of sample source (excreta or ileal digesta) and age of broiler chick on measurement of apparent digestible energy of wheat and barley.

The broiler chick bioassay measures AME of wheat- or barley-based diets, with or without an enzyme, from excreta (24-h collections at 8 or 16 d) and ileal digesta (17 d). The objective was to discuss the merits and accuracy of sample source (excreta vs ileal digesta) and bird age for determining the feeding value of wheat and barley. The bioassay utilized 80% of a test cereal grain, 20% basal diet containing 1.1% acid insoluble ash marker, and fed with or without an enzyme to four pens of six male broilers from 4 to 17 d. A total of 138 wheat and 97 barley samples (with and without an enzyme) were tested in 15 and five bioassays, respectively. Within each wheat or barley bioassay two control wheat and barley samples were measured. The among-pens and between-assays CV for AME were calculated for these control samples, and correlation coefficients between the measures were calculated for the controls and for all of the 138 wheat and 97 barley samples included in the assays. For wheat samples, values for AME were lowest for excreta samples collected at 8 d, and similar for excreta and ileal digesta samples collected at 16 and 17 d, respectively. For barley samples, the three values were significantly different. The among-pens and between-assay CV were low for AME among both wheat and barley samples. Correlation coefficients between several measures of AME at 8 and 16 d were significant for the control samples with enzyme supplementation. When all samples were included in the analysis, correlation coefficients between AME measures were moderate to high. On the basis of accuracy, precision, and cost, these data favor measuring AME on excreta samples at 16 d of age. Comparisons of number of pens of broilers used to determine AME would suggest that much of the variability predicted with four pens of six broilers each could be achieved with three, and possibly two pens of six broilers each, thereby greatly increasing the capacity of the assay to screen large numbers of samples.

Aging↗
PubMed2005

Determination of gross alpha, 224Ra, 226Ra, and 228Ra activities in drinking water using a single sample preparation procedure.

The current federal and New Jersey State regulations have greatly increased the number of gross alpha and radium tests for public and private drinking water supplies. The determination of radium isotopes in water generally involves lengthy and complicated processes. In this study, a new approach is presented for the determination of gross alpha, 224Ra, 226Ra, and 228Ra activities in water samples. The method includes a single sample preparation procedure followed by alpha counting and gamma-ray spectroscopy. The sample preparation technique incorporates an EPA-approved co-precipitation methodology for gross alpha determination with a few alterations and improvements. Using 3-L aliquots of sample, spiked with 133Ba tracer, the alpha-emitting radionuclides are isolated by a BaSO4 and Fe(OH)3 co-precipitation scheme. First the gross alpha-particle activity of the sample is measured with a low-background gas-flow proportional counter, followed by radium isotopes assay by gamma-ray spectroscopy, using the same prepared sample. Gamma-ray determination of 133Ba tracer is used to assess the radium chemical recovery. The 224Ra, 226Ra, and 228Ra activities in the sample are measured through their gamma-ray-emitting decay products, 212Pb, 214Pb/214Bi, and 228Ac, respectively. In cases where 224Ra determination is required, the gamma-ray counting should be performed within 2-4 d from sample collection. To measure 226Ra activity in the sample, the gamma-ray spectroscopy can be repeated 21 d after sample preparation to ensure that 226Ra and its progeny have reached the equilibrium state. At this point, the 228Ac equilibration with parent 228Ra is already established. Analysis of aliquots of de-ionized water spiked with NIST-traceable 230Th, 224Ra, 226Ra, and 228Ra standards demonstrated the accuracy and precision of this method. Various performance evaluation samples were also assayed for gross alpha as well as radium isotope activity determination using this procedure and the results were in close agreement with the assigned values. In addition, method comparison results of actual sample analyses agreed well with the ones performed using EPA-approved procedures. With a 3-L sample aliquot and 1,000-min counting time, the average gross alpha minimum detectable concentration (MDC) was about 0.002 Bq L(-1). The average MDC's for 224Ra, 226Ra, and 228Ra were 0.034 Bq L(-1), 0.017 Bq L(-1), and 0.036 Bq L(-1), respectively, based on a 3-L sample aliquot, 85% chemical yield, 40% intrinsic Ge detector, and 1,000-min count time. This method combines and simplifies the analytical procedures and reduces labor while achieving the precision, accuracy, and minimum detection limit requirements of EPA regulations.

Alpha Particles↗
PubMed2005

Quality control of slope-intercept measurements of glomerular filtration rate using single-sample estimates.

OBJECTIVES: Measurement of glomerular filtration rate (GFR) using the slope-intercept technique determines the plasma clearance curve by fitting a straight line to the logarithm of sample count rate. When two samples are used there is no check on the validity of curve fitting. GFR may also be estimated from single-sample concentrations. This study describes a method of quality control for the two-sample technique using the agreement between the one-sample and two-sample estimates. METHODS: GFR measurements using Tc-DTPA were performed on 225 adults and 100 children using two samples taken between 2 h and 4 h post-injection. The two-sample values obtained using the British Nuclear Medicine Guidelines slope-intercept technique were compared to one-sample estimates obtained using a new general equation. Equations describing the variation of GFR error with GFR value were defined. These were used to determine action levels giving the limits of expected agreement between slope-intercept and single-sample values. The use of these action levels for quality control was demonstrated in a further 120 GFR measurements. RESULTS: The variation of single-sample error estimate with GFR depended both on the time of sample and body surface area. For specific sample groups, the error variation with GFR could be approximated using a truncated quadratic equation. Four studies were identified as failing quality control in the dataset used to define the error equations. Two studies failed in the test dataset. CONCLUSIONS: One-sample equations give reliable estimates of GFR, which may be used for quality control of slope-intercept GFR assessment.

Adult↗
PubMed1997

Are coagulation studies on blood sampled from arterial lines valid?

Coagulation tests were performed on two venous blood samples and two blood samples from arterial lines taken from 79 patients on an intensive care unit. For the first arterial sample the discard volume was 4.5 ml and for the second arterial sample the discard volume was 16 ml. From each pair of venous samples a mean venous coagulation value was calculated. There were statistically significant differences between arterial and venous results and between the two arterial samples for activated partial thromboplastin time and thrombin time assays but not for prothrombin time, reptilase time and fibrinogen assays. However, these differences were sufficiently small to be of little clinical significance. The bias for the difference in activated partial thromboplastin time values between the first arterial sample and the venous sample was +1.24 s (limits of agreement: -4.39 to +6.87 s) and between the second arterial sample and the venous sample the bias was +0.89 s (limits of agreement: -3.25 to +5.03 s). Only 3.8% of first arterial samples and 1.3% of second arterial samples produced activated partial thromboplastin time values that were more than 10% longer than the corresponding venous values. No heparin was detectable in these arterial samples using a heparin assay (< 0.02 iu.ml-1). The differences between arterial and venous activated partial thromboplastin times were slightly but not significantly greater in subgroups of patients with moderately or severely deranged coagulation compared with a group with normal coagulation. We conclude that samples from arterial lines provide valid activated partial thromboplastin time results using a discard volume of either 4.5 ml or 16 ml.

Adult↗
PubMed1992

Clinical evaluation of oral fluid samples for diagnosis of viral hepatitis.

Oral fluid samples were compared with serum samples as a specimen source for hepatitis A, B, and C virus markers. Oral fluid was obtained with a treated absorbent pad and tested by using existing commercial enzyme immunoassays with only minor modifications. Compared with serum sampling the sensitivity and specificity of oral sampling were 100% (51 of 51 samples) and 98% (46 of 47 samples) for hepatitis A virus immunoglobulin M, 100% (29 of 29 samples) and 100% (29 of 29 samples) for hepatitis B virus surface antigen, and 100% (13 of 13 samples) and 100% (13 of 13 samples) for hepatitis C virus antibody, respectively. The decline of hepatitis A virus immunoglobulin M in oral samples was parallel to, though somewhat more rapid than, that of hepatitis A virus immunoglobulin M in serum samples. It is proposed that oral sampling represents a safer and more convenient procedure for reliable hepatitis virus testing than blood sampling and that it has wide application in patient and outbreak management.

Antibodies, Viral↗
PubMed1996

Detection of cytomegalovirus in blood donors by PCR using the digene SHARP signal system assay: effects of sample preparation and detection methodology.

Cytomegalovirus (CMV) is an important cause of transfusion-associated morbidity and mortality; however, only 0.4 to 12% of the blood products obtained from seropositive blood donors transmit infection. The effects of three commercially available whole-blood sample preparation kits on the detection of CMV PCR products by a semiquantitative adaptation of the Digene SHARP Signal System Assay (DSSSA) in samples from volunteer blood donors was assessed. Of 101 samples from seropositive blood donors, CMV was detected in 0 (0%) of the samples extracted with a QIAamp blood kit (QIAGEN), 1 (1%) of the samples extracted with an Amplicor whole-blood specimen preparation kit (Roche), and 8 (8%) of the samples extracted with an Isoquick nucleic acid extraction kit (modified by the addition of carrier tRNA) (Microprobe). CMV DNA was not detected in samples from seronegative blood donors (n = 13). Nested PCR of selected samples confirmed the detection of CMV in the sane eight samples extracted with the modified Isoquick nucleic acid extraction kit and detected an additional nine CMV-positive samples (n = 50). Samples from volunteer blood donors contain low copy numbers of CMV DNA. PCR amplification of such specimens can result in analytical sampling errors, giving results similar to the variations in titers recognized during determinations of the 50% tissue culture infective dose. The detection of CMV in blood samples from volunteer blood donors by PCR is a function of sample preparation, amplification conditions, and detection methodology. Accurate assessments of the clinical utility of CMV DNA detection by nucleic acid amplification for blood product screening and patients will require highly standardized and quantitative methodology.

Blood Donors↗
PubMed2003

Development of a LightCycler PCR assay for detection and quantification of Aspergillus fumigatus DNA in clinical samples from neutropenic patients.

The increasing incidence of invasive aspergillosis, a life-threatening infection in immunocompromised patients, emphasizes the need to improve the diagnostic tools for this disease. We established a LightCycler-based real-time PCR assay to detect and quantify rapidly, specifically, and sensitively Aspergillus fumigatus DNA in both bronchoalveolar lavage (BAL) and blood samples from high-risk patients. The primers and hybridization probes were derived from an A. fumigatus-specific sequence of the mitochondrial cytochrome b gene. The assay is linear in the range between 13.2 fg and 1.3 ng of A. fumigatus DNA, corresponding to 3 to 300,000 CFU per ml of BAL fluid or blood. No cross-amplification was observed with human DNA or with the DNA of fungal or bacterial pathogens. For clinical evaluation we investigated 10 BAL samples from nine neutropenic patients with malignant hematological diseases and 12 blood samples from seven neutropenic patients with malignant hematological diseases. Additionally, we tested one blood sample and one BAL sample from each of two neutropenic patients. In order to characterize the validity of the novel PCR assay, only samples that had shown positive results by a previously described sensitive and specific nested PCR assay were tested. Twelve of 12 BAL samples and 6 of 14 blood samples gave positive results by the LightCycler PCR assay. Eight of 14 blood samples gave negative results by the novel method. The LightCycler PCR-mediated quantification of the fungal burden showed 15 to 269,018 CFU per ml of BAL sample and 298 to 104,114 CFU per ml of blood sample. Twenty of 20 BAL samples and 50 of 50 blood samples from subjects without evidence of invasive pulmonary aspergillosis (IPA) were PCR negative. Compared to a previously described nested PCR assay, these preliminary data for the novel real-time PCR assay indicate a less sensitive rate of detection of IPA in high-risk patients, but the assay may be valuable for quantification of the fungal burden in individual clinical samples.

Aspergillosis↗
PubMedDate not supplied

Contribution of the endocervical Cytobrush sample to the diagnosis of cervical lesions.

OBJECTIVE: To compare the contribution of endocervical Cytobrush samples to wooden spatula samples in the detection of cervical preneoplastic lesions. STUDY DESIGN: Cytobrush sampling was performed on 56,120 women in conjunction with ectocervical spatula sampling, resulting in two smears per patient. Almost all women with cytologic diagnoses of high grade squamous intraepithelial lesions (CIN 3) or higher were biopsied. RESULTS: For the 221 CIN 3, the contribution of the endocervical sample was clearly more efficient, with diagnosis achieved on 98% of the endocervical samples and on 62% of the ectocervical ones. In the 674 low grade squamous epithelial lesion cases, the endocervical samples were diagnostic in 79% of cases and the ectocervical smears in 64%. Thus, endocervical sampling proved to be superior in the recognition of precancerous lesions. In 93% of the 53 squamous carcinomas, cancer cells were found in both ectocervical and endocervical samples and in 7%, exclusively in endocervical smears. In 76% of the 21 adenocarcinomas, both samples were positive, and in 23% only the endocervical sample contained cancer cells. CONCLUSION: The Cytobrush samples were more efficient in the detection of intraepithelial neoplastic lesions, suggesting that most of them originate in the endocervical epithelium. If the sampling were limited to endocervical brushing, 14% of cervical lesions would not have been detected in the smear. The prominence of preneoplastic cells in the endocervical samples might indicate that the original glandular epithelium is the major site of cervical carcinogenesis.

Adenocarcinoma↗
PubMed2006

Use of pooled samples for the detection of Salmonella in feces by polymerase chain reaction.

Many epidemiological studies of Salmonella rely on conventional bacteriological culture methods to detect Salmonella in fecal samples. These culture-based methods are inefficient for epidemiological studies in populations with a low prevalence of Salmonella. The objective of this study was to optimize a protocol that uses pooled Salmonella enrichment broth cultures of bovine feces and polymerase chain reaction (PCR) for the detection of the invA gene of Salmonella in feces. In one field trial, 196 animals were sampled, and all samples were tested by culture, invA PCR on individual samples, invA PCR on pools of 5 samples, and BAX PCR on individual samples. All assays showed a high agreement on individual samples (kappa > or = 0.75). The invA PCR was run on each of 40 pools and detected 19 of 22 culture-positive pools. In another field trial, 152 samples were taken from 4 dairies, and the invA PCR was performed on pools of 5 samples in addition to bacteriological culture of individual samples. Salmonella was detected in 5 of the 32 pools (7 total positive samples) by both PCR and culture. One pool was PCR-positive but culture-negative. Pooling did not dramatically affect the performance of the invA PCR; most of the culture-positive samples were detected, including all of the samples when there were 4 or more Salmonella colonies on the agar plate. Based on these field trials, invA PCR on pooled samples appears to be an efficient method of Salmonella detection as long as Salmonella loads are not extremely low.

Animals↗
PubMed2000

Comparison of clinical pathology parameters with two different blood sampling techniques in rats: retrobulbar plexus versus sublingual vein.

Blood samples were taken from the retrobulbar venous plexus or the sublingual vein of male HamIbm:Wist rats to compare clinical pathology parameters between the two sampling techniques. By analogy with a pharmacokinetic study, blood was sampled six times during one day from unfasted animals. After 3 weeks of recovery, blood was taken from fasted animals on a single occasion. In addition, prolactin and corticosterone levels were determined to compare stress-related effects between the two sampling methods. Body weight development and food consumption were similar after single as well as after repeated blood sampling for the two blood sampling techniques. Haemotological evaluation showed a gradual decrease in erythrocyte count, haemoglobin concentration and haematocrit after repeated blood sampling. Repeated withdrawal of blood samples over 24 h corresponding to approximately 22% of the total blood volume resulted in a decrease in red blood cell parameters by up to 30%. The withdrawal of approximately 10% of the total blood volume was associated with a decrease in these parameters by up to 10% and should not be exceeded for animal welfare reasons and to allow a reliable evaluation of data in a study. Repeated blood sampling was associated with an initial decrease in the number of white blood cells, mainly due to a reduction in lymphocytes; white blood cell counts were slightly increased one day after. The decrease in lymphocytes and the increase in neutrophils after repeated sampling were generally slightly more pronounced in the blood from the retrobulbar plexus than from the sublingual vein. Comparison of serum clinical chemistry data showed significantly higher activities of creatine kinase and aspartate aminotransferase in samples from the retrobulbar plexus. These findings suggest a higher degree of tissue damage with blood sampling from the retrobulbar plexus than from the sublingual vein. Despite a large inter-individual variability, higher mean values of prolactin on each occasion and corticosterone after a single sample in fasted animals indicate a higher stress associated with blood sampling from the retrobulbar plexus.

Amylases↗