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At least 1,423 records · Page 79Linked to original sources
PubMed1995

Interlaboratory quality control and status of n-hexane biological monitoring in Japan.

This paper reports the problem of interlaboratory quality control and the actual condition of biological monitoring of n-hexane among the seven major laboratories specializing in clinical chemistry tests, where more than 80% of the total urine specimens in Japan have been analyzed after the beginning of biological monitoring of n-hexane in 1989. First, transportation conditions of urine specimens and transportation effects on measurement results were studied. The seven major laboratories carried urine specimens at distances of more than 450 km from the University of Occupational and Environmental Health (UOEH) to the respective laboratories and had at least one transit terminal where specimens from various areas were collected and transferred to the analytical laboratories. All laboratories used cooler boxes with dry ice or ice bars and stored the specimens in freezers or refrigerators. Specimens arrived at the final destinations within 24 hours. The transportation from institutes for health examination to the laboratories did not affect the measurement results of 2,5-hexanedione (HD), a determinant of n-hexane biological monitoring. Interlaboratory cross-checks were performed among the seven major laboratories and four institutes for occupational health examination that have their own analytical laboratories. All of the laboratories analyzed HD by acid hydrolysis (pH < 1.0); interlaboratory differences were recognized at the first cross-check. After some laboratories intensified gas chromatography (GC) maintenance and changed to a new column, the interlaboratory variation lessened.(ABSTRACT TRUNCATED AT 250 WORDS)

Environmental Monitoring↗
PubMed2003

ER quality control can lead to retrograde transport from the ER lumen to the cytosol and the nucleoplasm in plants.

Quality control in the secretory pathway is a fundamental step in preventing deleterious effects that may arise by the release of malfolded proteins into the cell or apoplast. Our aims were to visualise and analyse the disposal route followed by aberrant proteins within a plant cell in vivo using fluorescent protein technology. A green fluorescent protein (GFP) fusion was detected in the cytosol and the nucleoplasm in spite of the presence of an N-terminal secretory signal peptide. In contrast to secreted GFP, the fusion protein was retained in the cells where it was degraded slowly, albeit at a rate much higher than that of the endoplasmic reticulum (ER)-retained derivative GFP-HDEL. The fusion protein could not be stabilised by inhibitors of transport or the cytosolic proteasome. However, the protein is a strong lumenal binding protein (BiP) ligand. Complete signal peptide processing even after long-term expression in virus-infected leaves rules out the possibility that the documented accumulation in the cytosol and nucleoplasm is because of the bypassing of the translocation pores. The data are consistent with the hypothesis that the fusion protein is disposed off from the ER via a retrograde translocation back to the cytosol. Moreover, accumulation in the nucleoplasm was shown to be microtubule dependent unlike the well-documented diffusion of cytosolically expressed GFP into the nucleoplasm. The apparent active transport of the GFP fusion into the nucleoplasm may indicate an as yet undiscovered feature of the ER-associated degradation (ERAD) pathway and explain the insensitivity to degradation by proteasome inhibitors.

Biological Transport↗
PubMed2000

Quality control in the discovery, reporting, and recording of genomic variation.

The usefulness of any database is dependent on the quality of its content. This is so for mutation databases and has been a continuing concern for those interested in such databases. This article discusses the critical points that determine the quality of the data, such as PCR errors, incomplete scanning, examination of the effect of the variation, and reporting and deposition of the mutations in a database. To illustrate the importance of quality control in mutation curation, nine articles reporting 34 novel phenylketonuria mutations were surveyed for the criteria believed to be important in describing mutations. Many articles were deficient in entries in several criteria, but there was still a high degree of certainty that the described mutations caused disease. Finally, strategies to eliminate errors and to enhance or indicate quality are discussed, including expression, the review process, checking deductions, and typing and encouraging compliance. Models for the future are also discussed.

DNA↗
PubMed1996

Pitfalls in the immunophenotyping of leukaemia and leukaemic lymphomas: survey of 9 years of quality control in The Netherlands. Dutch Cooperative Study Group on Immunophenotyping of Haematological Malignancies (SIHON).

During the last decade, biannual quality controls were performed in the Netherlands focusing on the immunophenotyping of leukaemic haematological malignancies. All results on 48 specimens obtained by 18-34 laboratories were analysed. The interlaboratory variability and percentages of discordant results from 30 markers were measured by assessing false positive or negative (cut-off 10%) results in comparison with median results of the group. The quality of the immunophenotypic diagnoses obtained from the interpretation of these markers in relation to clinical data was evaluated by scoring them as 'correct', 'minor fault', 'major fault', 'not based upon the markers used', and 'no diagnosis', CD3, CD8, CD19, CD61 and Sm lambda had the lowest percentage discordancy (sum of total negative and positive discordant values 5-7.5% of assays): CD13, CD15, cyCD22, CD33 and TdT scored worst with 14-20% cumulative discordancy. The analysis of each diagnosis yielded 78% acceptable immunophenotypic conclusions (correct 54% and minor fault 24%). It appeared that the major faults in immunophenotyping were caused by suboptimal antibody selection and erroneous interpretation of the results obtained, rather than by technical errors. Large differences per diagnostic category were observed, with the best scores for mature B-cell leukaemias, AMLs and common-ALL, and the poorest scores for T-cell malignancies which were correctly diagnosed in only 24-60% of specimens. Mature T-NHL and T-PLL were mistakenly diagnosed as T-ALL by 40% of the centres. Misinterpretation of TdT immunofluorescence or omitting this marker contributed significantly to these wrong diagnoses. A median of 4% of immunophenotypic diagnoses were not based on a correct panel of antibodies, but upon the morphology of the accompanying blood smear, and was often flawed by overinterpretation. In conclusion, both the technical performance of immunophenotyping of haematological malignancies in The Netherlands and the procedure by which a final diagnosis is obtained needs improvement, especially for T-cell malignancies.

False Negative Reactions↗
PubMed1998

[Evaluation of the relevance of the target animal safety test for the quality control of veterinary immunological medicinal products]

The legal requirements for veterinary vaccines require the testing of each new vaccine batch for safety. In the European Pharmacopoeia a target animal safety test (TAST) is regularly required as a final product test for almost all vaccine batches. This test is also required in the "General requirements for the production and control of live mammalian viral and bacterial vaccines (GRLMV)" and the "General requirements for the production and control of inactivated mammalian viral and bacterial vaccines (GRIMV)" by the European Union. In several publications the relevance of this TAST has been questioned. Particularly, it is questionable whether this animal test is able to give a significant contribution to the safety of immunologicals considering today"s standards of the quality control of animal vaccines, e.g. Good manufacturing practice and Good laboratory practice. However, due to a lack of sufficient amount of data the relevance of this animal test is discussed contradictorily. 1934 batch release protocols were sent to the Paul-Ehrlich-Institut between January of 1994 and December of 1997 for bacterial vaccines including combinations with viral antigens, vaccines against parasitic or fungal diseases and sera. During that period the manufacturers needed 5250 animals to perform the TAST. Obviously, the requirement for the TAST has a great impact on the animal numbers needed for the quality control of veterinary vaccines. The deletion of the TAST as a routine test could reduce the number of animals considerably. Preliminary results of a survey on this problem are presented and discussed.

Journal Article↗
PubMed1992

Quality control of dietary data collection in the CARDIA study.

The Coronary Artery Risk Development in (Young) Adults (CARDIA) Study developed and implemented quality control (QC) measures to minimize misclassification associated with dietary data. Manual and automated data inspection were used to monitor quality. Of the 5111 participants who completed a dietary history, 717 (14%) had dietary forms reviewed and 153 (3%) had the interview audiotaped. Results show that for the 717 forms reviewed, the overall form completion error rate was 0.22% and the "critical" error rate (i.e., those errors impacting on nutrient computations) was 0.12%. The proportion of forms free of any type of error increased over time (p less than 0.0001). The discrepancy rate in recording and interviewing methods as estimated from the 153 audiotaped interviews was 0.7%. Inter-interviewer differences were small as indicated by the audiotaped interviews and the proportion of error-free forms completed by interviewers. The results indicate that the dietary data collected in CARDIA were completely and accurately recorded for use in analysis.

Adolescent↗
PubMed1997

Quality-control (QC) performance measures and the QC planning process.

Numerous outcome measures can be used to characterize and compare the performance of alternative quality-control (QC) strategies. The performance measure traditionally used in the QC planning process is the probability of rejecting an analytical run when a critical out-of-control error condition exists. Another performance measure that naturally fits within the total allowable error paradigm is the probability that a reported test result contains an analytical error that exceeds the total allowable error specification. In general, the out-of-control error conditions associated with the greatest chance of reporting an unacceptable test result are unrelated to the traditionally defined "critical" error conditions. If the probability of reporting an unacceptable test result is used as the primary performance measure, worst-case QC performance can be determined irrespective of the magnitude of any out-of-control error condition that may exist, thus eliminating the need for the concept of a "critical" out-of-control error.

Chemistry, Clinical↗
PubMed1974

Quality control in cervical cytology.

From surveys conducted by the authors it is concluded that the best and most acceptable quality control methods in cytology are those from within the laboratory. Most of these have results which can be reported centrally. Where the overall control and codes of practice are high, there the results are the most reliable, as sources of error from whatever cause are quickly brought to light. These conclusions are illustrated by data from the five centres and correlated in the tables.

Adult↗
PubMed2006

Quality control of equipment used in digital and interventional radiology.

Digital and interventional radiology are increasingly important areas of radiology. Quality control (QC) of such equipment is of particular importance to avoid unnecessary high doses and to help to achieve good image quality. Within the DIMOND III project, equipment requirements and specifications for digital and interventional radiology have been formulated. A protocol for QC tests has been drafted based on various national and international recommendations. Tests are included for various parts of the imaging chain, i.e. X-ray tube and generator, X-ray tube control system, laser printer and display station, and image quality and patient dose. Preliminary tolerance levels have been set for the various tests, after initial measurements. To check the suitability of QC tests and stated tolerance levels, measurements were made at the University Hospital Gasthuisberg in Leuven for equipment used for paediatric radiology and a unit used for chest examinations. The results of the various tests are reported.

Humans↗
PubMedDate not supplied

Brain death: epidemiology and quality control of solid organ donor generation.

Successful solid organ transplant programs need effective organ procurement systems. Evaluating and maintaining the quality of an organ procurement system requires multilevel institutional coordination as well as reliable information regarding potential donors. The objective of this study was to analyze the potential to generate adult solid organ donors at a countrywide level as well as at individual hospital levels in Uruguay from 2000 to 2002. The analyzed factors included: encephalic deaths (brain deaths) officially registered by the National Bank of Organs and Tissues (BNOT), the distribution of these individuals among the intensive care units (ICUs) located at various hospitals, the number of Real Donors at each hospital, and the relation between the brain deaths and the number of ICU beds equipped with artificial respirators. The Uruguayan solid organ donation rate is relatively high among Latin American Countries, but low in relation to developed countries. The conversion of potential donors to actual donors is similar to that seen in developed countries. However, the registered incidence of brain deaths in relation to the number of ICU beds is surprisingly below the recognized standard figure. To approach the reasons for this difference, efficient quality control mechanisms are needed in the various ICUs as well as comprehensive medical case history reviews of all patient records.

Brain Death↗
PubMed2025

The glycoprotein quality control factor Malectin promotes coronavirus replication and viral protein biogenesis.

Coronaviruses (CoV) rewire host protein homeostasis (proteostasis) networks through interactions between viral nonstructural proteins (nsps) and host factors to promote infection. With the emergence of SARS-CoV-2, it is imperative to characterize host interactors shared across nsp homologs. Using quantitative proteomics and functional genetic screening, we identify conserved proteostasis interactors of nsp2 and nsp4 that serve pro-viral roles during infection of murine hepatitis virus - a model betacoronavirus. We uncover a glycoprotein quality control factor, Malectin (MLEC), which significantly reduces infectious titers when knocked down. During infection, nsp2 interacts with MLEC-associated proteins and the MLEC-interactome is drastically altered but retains association with the Oligosaccheryltransferase (OST) complex, a crucial component of viral glycoprotein production. MLEC promotes viral protein levels and genome replication through its quality control activity. Lastly, we show MLEC promotes SARS-CoV-2 replication. Our results reveal a role for MLEC in mediating CoV infection and identify a potential target for pan-CoV antivirals.

Biochemistry and Chemical Biology↗
PubMed2001

[Everyday quality control at clinical-biochemical laboratories using chi square test].

The possibility of using chi 2 statistical test for quality control of laboratory studies was evaluated in a practical laboratory. In the overwhelming majority of cases the chi 2 test of analytical series, estimated from previous results or total sum of results of a month, indicates with certainty that this series is a random sampling. This unambiguously indicates analytical reliability of the results. Division of patients into inpatients and outpatients did not improve this parameter. The results were regularly much better for some analytical methods in comparison with other methods, which indicates their higher reliability.

Algorithms↗
PubMed1996

Quality control in IVF with mouse bioassays: a four years' experience.

OBJECTIVE: We analyzed retrospectively the relevance of 4 years of quality control on homemade culture medium with the mouse IVF and zygote bioassay. DESIGN: In vitro or in vivo fertilized mouse oocytes were cultured in each batch of medium. Two-cell-stage and expanded blastocyst development was recorded for each batch of medium. Data on fertilization and embryo quality obtained in human in vitro fertilization were recorded for each batch. IVF treatment cycles for male infertility and cycles with sperm microinjection were excluded. RESULTS: Human oocyte fertilization dropped from 60 to 54%, respectively, from 57 to 41% in a significant way (P < 0.05 resp. P < 0.01) and the human mean embryo score decreased from 4.17 +/- 1.21 to 3.69 +/- 1.06 (P < 0.05) when media were used with a low two-cell-stage development (< or = 75%) for the mouse zygote or mouse IVF bioassay. The pregnancy rate was not affected. CONCLUSIONS: Media with high scores in mouse bioassays show higher fertilization rates and better embryo quality when used for human IVF.

Animals↗
PubMed1992

A tool for the design and evaluation of alternative quality-control procedures.

I have developed an interactive microcomputer simulation program for the design, comparison, and evaluation of alternative quality-control (QC) procedures. The program estimates the probabilities for rejection under different conditions of random and systematic error when these procedures are used and plots their power function graphs. It also estimates the probabilities for detection of critical errors, the defect rate, and the test yield. To allow a flexible definition of the QC procedures, it includes an interpreter. Various characteristics of the analytical process and the QC procedure can be user-defined. The program extends the concepts of the probability for error detection and of the power function to describe the results of the introduction of error between runs and within a run. The usefulness of this approach is illustrated with some examples.

Chemistry, Clinical↗
PubMed1992

Possibilities of software phantoms for quality control of KBS in nuclear medicine.

The assessment of the results of a "knowledge-based system" (KBS) for quality control is a basic requirement for clinical application: Large numbers of test studies are necessary in order to cover as widely as possible the spectrum of cases to be analyzed by the KBS. The use of original patient data as test data is one possibility, but real data are provided unevenly. This is due to the set of characteristics which are relevant to the analysis. Data are available in a limited quantity only. This implies a remaining set of unvalidated cases which are not represented in the data pool. The software phantom is an approach towards systematically guided validation. It permits the generation of test data adjusted to the demands of the validation.

Artificial Intelligence↗
PubMed2000

Performance evaluation and planning for patient-based quality control procedures.

In a recent publication, the effect of the length of time between the routine testing of quality-control (QC) samples on QC performance was studied using a newly proposed performance measure: the average number of patient samples that contain unacceptable analytic error due to an out-of-control error condition (ANPTE). We show that ANPTE also perfectly suits the evaluation of patient-based QC procedures. We used ANPTE to study the effect of the number of patient results averaged and the width of the truncation limits on an average of normals QC procedure. Estimates of ANPTE were obtained by using computer simulations that use actual patient result distributions. Based on ANPTE, the conclusions about the effects of truncation limits and number of patient results averaged on the performance of an average of normals QC procedure are substantially different from those described by others using the probability of error detection to characterize QC performance.

Aspartate Aminotransferases↗
PubMed1983

Quality control parameters for susceptibility tests with 30-micrograms netilmicin disks.

A nine-laboratory cooperative study was performed to evaluate quality control parameters for susceptibility tests with 30-micrograms netilmicin disks. The applicability of currently recommended zone-size limits was confirmed. However, alternative statistical methods suggested that tighter control limits might be more appropriate but would require better standardization of reagents, especially Mueller-Hinton agars.

Agar↗