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Results for “quality control”

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At least 1,117 records · Page 62Linked to original sources
PubMed1978

Rapid miniaturized chromatographic quality control procedures for iodinated radiopharmaceuticals.

A rapid, miniaturized chromatographic system was developed to determine the labeling efficiency of iodinated radio-pharmaceuticals including I-131 orthoiodohippurate, I-131 rose bengal, I-125 RISA, and I-131 19-iodocholesterol. The system consists of three specific chromatography strips (Whatman 31ET paper chromatography, silica gel and silicic acid instant thin-layer chromatography) and three solvents (chloroform:glacial acetic acid in a 1.00:0.05 v/v mixture, absolute methanol, and 0.9% sodium chloride). The strips are color-coded, miniaturized, and appropriately labeled. The chromatographic quality control procedures are easy to use, rapid, and can be incorporated easily in a routine quality control program.

Chromatography↗
PubMed2005

Quality control: another player joins the ERAD cast.

The quality control system known as ERAD removes misfolded proteins from the ER to the cytosol for degradation. The AAA ATPase Cdc48p and ubiquitin ligases play crucial roles; their relationship has been unclear, but recent work has shown that the membrane protein Ubx2p links their functions in yeast.

Adenosine Triphosphatases↗
PubMed1977

Rapid miniaturized chromatographic quality-control procedures for Tc-99m radiopharmaceuticals.

Our laboratory has adopted a complete miniaturized charomatography system for Tc-99m radiopharmaceuticals in order to improve upon the commercial systems currently available. Three distinct, separate, chromatographic procedures are used to determine the labeling efficiencies of Tc-99m-labeled sulfur colloid, MAA, stannous chloride, phytate, DMSA, DTPA, pyrophosphate, diphosphonate, methylene diphosphonate, polyphosphate, and glucoheptonate. The chromatographic systems include Whatman 31 ET paper and acetone, Gelman ITLC-SG and 0.9% sodium chloride, and Gelman ITLC-SA and acetone. The chromatographic strips are miniaturized (1 X 6 cm), colored-coded, marked, and numbered. All the chromatographic quality-control procedures are simple, rapid, and can easily be incorporated into the routine quality-control program of any nuclear medicine facility.

Chromatography↗
PubMed2005

Yeast genomics in the elucidation of endoplasmic reticulum (ER) quality control and associated protein degradation (ERQD).

The endoplasmic reticulum (ER) is the eukaryotic organelle where most secreted proteins enter the secretory pathway. They enter this organelle in an unfolded state and are folded by a highly active folding machinery to reach their native state. The ER contains an efficient protein quality control system, which recognizes malfolded and orphan proteins and targets them for elimination by a mechanism called ER-associated degradation (ERAD). Both processes are tightly linked, and they will be abbreviated as ERQD (ER quality control and associated degradation). Because ERQD is highly conserved from yeast to man, the easy amenability of yeast to genetic and molecular biological studies combined with the knowledge of its genome and proteome makes it a preferred organism to study such "housekeeping" functions of eukaryotic cells. New genomic and proteomic methods have led to new experimental concepts. Genome-wide screens using genomic deletion libraries led to the identification of genes involved in the processes in question. Using such a genome-wide approach, we devise a sensitive growth test for selection of yeast mutants defective in ERQD. A chimeric protein (CTL*) was generated consisting of the ER luminal, N-glycosylated CPY* protein fused to a transmembrane domain and cytoplasmic 3-isopropylmalate dehydrogenase, the Leu2 protein. In addition, the nonglycosylated ER-membrane-located ERQD substrate Sec61-2p was fused to Leu2p (Sec61-2-L*). Cells carrying a LEU2 deletion can only grow on medium lacking leucine when the chimeric protein CTL* or Sec61-2-L* is not degraded. Thus, only mutant cells defective in an ERQD component can grow. A genome-wide screen can be performed by transforming the CTL* or Sec61-2-L* coding DNA into the approximately 5000 individual deletion mutants of the EUROSCARF yeast library. Examples for new components required for ERQD found by this method are the mannose-6-phosphate receptor domain protein Yos9p and the ubiquitin domain proteins Dsk2p and Rad23p.

Endoplasmic Reticulum↗
PubMed2003

Can Westgard Quality Control Rules determine the suitability of frozen sperm pellets as a control material for computer assisted semen analyzers?

PURPOSE: To evaluate the drop-to-drop and pellet-to-pellet repeatability and stability of frozen sperm pellets. METHODS: Ten pellets were thawed per batch (low and normal concentration) and evaluated by two investigators to establish a quality control chart. Then low and normal concentration pellets were thawed and evaluated daily for 10 days by both investigators. The values for both investigators were averaged and plotted on the chart. RESULTS: The low sperm concentration specimen had a systematic error while the normal sperm concentration specimen had a random error as well as a systematic error. The low sperm concentration specimen violated the warning rule for motility whereas the normal concentration violated the warning rule, the random error rule, and the systematic error rule when applied to motility. CONCLUSIONS: Frozen sperm pellets are not acceptable as a daily-use quality control material for semen analysis when using a computer assisted semen analyzer.

Cryopreservation↗
PubMed2005

[Quality control: sensitivity of the indirect antiglobulin test by filtration].

For ten years, the working party of immunohaematology of the French Society of Blood Transfusion organizes a quality control. After the modification of the law about the realization of erythrocyte typing and detection of unexpected red cell allo-antibodies, the quality control was performed in order to determine the sensitivity of the indirect antiglobulin test by filtration with a standard anti-RH1(D) produces by the National Reference Center of Blood Groups.

Blood Group Antigens↗
PubMed1983

Methods for internal quality control in the mycobacteriology laboratory.

A proposal is given for internal quality control in the mycobacteriology laboratory by continuously monitoring the yields of positive results in microscopy and culture as well as the contamination rates of the culture media. The figures thus obtained can be processed as is customary done in clinical chemistry in order not only to detect deviations, but also to discern whether they are due to chance or whether they indicate a change in the quality of performance. Some examples are given to illustrate the possibilities offered by this control system.

Culture Media↗
PubMed1988

Quality control and drug utilization review.

The impact of drug utilization review on quality control is outlined. Special attention is given to a drug utilization review at the individual patient level for which the methodology for implementation and maintenance are described, with special emphasis on the cyclic character of the process.

Drug Utilization↗
PubMed1979

Quality control of agar diffusion susceptibility tests.

Since its beginning in 1974 over 180 laboratories have participated in the Microbiology Program of The College of American Pathologists Quality Assurance Service submitting a total of 2,372,000 individual antibiotic determinations on three quality control reference stains. Eighty-nine and five tenths percent of these determinations were obtained using the standard Bauer-Kirby method; 8.4% using the agar overlay modification of Barry and associates. Standard statistical analysis of data obtained using the Bauer-Kirby method have been reported for each antimicrobic/reference strain combination. Comparisons have been made between the QAS data and those data obtained in earlier collaborative studies which currently serve as precision and accuracy control limits. In many cases QAS data exceed the existing control limits.

Agar↗
PubMedDate not supplied

An Italian program of external quality control for chromogranin A (CgA) assay: state of the art of CgA measurement.

Chromogranin A (CgA) is a secretory protein produced by many neuroendocrine cells. Circulating levels of CgA have been found to be elevated in a variety of neuroendocrine tumors and may facilitate the diagnosis and management of patients with functioning as well as non-functioning forms. However, up to now the analytical methods used for assaying intact CgA and CgA-derived peptides in the circulation of patients have not been monitored in Italy by an external quality control program. Within the framework of a Ministry of Health project an external quality control program was developed to investigate the state of the art of CgA determination in Italy and to monitor the performance of laboratories carrying out this assay. This paper deals primarily with the former of these aspects. Every laboratory received the study protocol together with a questionnaire to be returned before receipt of the samples to be assayed. Serum and plasma samples obtained from a pool of routine specimens were prepared at three different concentrations of CgA, aliquoted, frozen at -80 degrees C and mailed in dry ice to the participating laboratories. Of the 43 laboratories, 21 used IRMA, 21 used ELISA and one used RIA. There was a wide range in the time of kit utilization and the number of samples assayed per year, which indicated that the participating group was heterogeneous with regard to their experience in the determination of CgA. Most laboratories routinely used serum and plasma for IRMA and ELISA, respectively, and different data fitting approaches were employed. Further analyses will investigate the possible influence of these preanalytical factors on laboratory performance.

Biomarkers, Tumor↗
PubMed2000

Controlled introduction of the sentinel node biopsy in breast cancer in a multi-centre setting: the role of a coordinator for quality control.

AIMS: It is proposed that sentinel node biopsy should replace axillary lymph-node dissection. We analysed the role of a coordinator in the introduction of the sentinel node biopsy in breast cancer in a multi-centre setting to assure standardization and quality control. METHODS: We included 232 operable breast cancer patients. Part of the procedure was an ultrasound examination of the axilla with fine needle aspiration cytology. The sentinel node was identified with 99m-Technetium and Patent Blue. RESULTS: The results of the procedure, sensitivity and false negativity, were the same for the three participating hospitals. We think this is mostly due to the coordinator who supplied information about the technique, pitfalls and results to all teams. CONCLUSIONS: Our experience regarding the organization aspects of introducing the sentinel node procedure in a multi-centre setting now serves as a model in organizing its application in a much wider number of hospitals.

Axilla↗
PubMed1998

[Automated procedures for radiation protection and quality controls in conventional diagnostic radiology].

To comply with regulations on radiation protection and quality controls is a difficult task when operating in large hospitals. This leads to the need of defining more efficient protocols and of making procedures as automated as possible. The procedure described in this paper is based on a multimeter controlled by a portable PC, and on a spreadsheet program for data processing. Multimeter data are automatically imported and processed, in order to assess the compliance of measured parameters with the reference regulations (IEC recommendations, radiation safety rules, etc.). The spreadsheet is permanently linked to a data base. It is therefore possible to perform the controls and to store the corresponding results in a shorter time (one hour per machine, approximately). By using a properly chosen quality index, monitoring the efficiency of the diagnostic equipment is also possible, which allows to prevent the onset of severe failures.

Computers↗
PubMedDate not supplied

Quality control of the SIGMA applicator using a lamp phantom: a four-centre comparison.

An elliptical phantom with a fat-equivalent ring and lamp matrix was developed for observing the power distribution in ring applicators used for regional hyperthermia. This phantom was used on four European BSD-2000-type therapy systems under routine conditions to test the quality of the SIGMA-60 applicator (systems in Berlin, Essen, Munich and Rotterdam). Frequency-dependent focusing imbalances were observed in all systems. At the time of the quality control test two of the systems displayed considerable errors in their settings. The system setups and possible ways of correcting errors are described in detail. Small maladjustments are caused by coupling effects between antennas and their surroundings and by interactions between the coaxial cables which supply the power. Serious distortions can be caused by phase errors and defects in cables or plugs; the latter can result in significant long-term restrictions on the ability to control the SAR (specific absorption rate) distribution in a way the user may not notice. The measurements gained from these four systems confirm the need for a practical and universal procedure for quality control in regional hyperthermia.

Europe↗
PubMedDate not supplied

[Quality control methods in sero-immunologic tests for infectious diseases].

The different quality control methods which should be used in seroimmunological assays for detection of antibodies in infectious disease are analyzed. The concepts of reliability, sensitivity, specificity, cut off, efficacy and predictive value are described, explained how they can be calculated and exemplified. The statistics which can be used for comparing results in different situations it is also referred.

Humans↗
PubMedDate not supplied

[The methodology of quality control in parenteral nutrition. I. The application of a program in patient selection].

The establishing of indications for parenteral nutrition and the evaluation criteria for the nutritional state of patients used in selecting the candidates for parenteral nutrition are the two main pillars upon which the rationalization of nutritional therapy iv is based. This is an important aspect which conditions the quality of therapeutics. The aim of this study is to apply a quality control programme in the process of selecting candidates for parenteral nutrition. The programme was applied retrospectively to 148 patients. The following parameters were evaluated as quality indicators, based on criteria and standards: "Indications", "Clinical Justification", "Evaluation of the Nutritional State at the commencement of PN", and "Administration of Albumin". The degree of compliance obtained for each of these indicators (100; 87.4; 88.0 and 93.9% respectively) showed no statistically significant difference from the previous standards (100, 80, 80 and 100 respectively). The quality control results obtained have permitted us to select the right candidate for PN, and is a useful tool for improving this therapy through the establishing of new objectives.

Aged↗
PubMedDate not supplied

[Quality control in tumor marker values: methology, results and potential problems].

Ensuring the quality is one of the first preoccupations of every biologist. However, measuring the circulating tumor markers could be more vital especially that the result is decisive for the diagnostic and the therapeutic attitude. In this study, we report methods used for an internal and external < or = quality control < or = program applied in the immunology laboratory of Sfax university hospital for the dosage of tumor markers AFP, CEA and CA15-3. The results obtained are analysed comparatively with those reported in literature. Factors causing discrepancies in the results of tumor marker measurements are recalled.

Biomarkers, Tumor↗
PubMed1997

GEMHEP multicenter quality control study of PCR detection of GB virus C/hepatitis G virus RNA in serum.

PCR is, to date, the only available tool for the detection of GB virus C (GBV-C) and hepatitis G virus (HGV) RNAs. Twenty-two French laboratories participated in a quality control study to assess the sensitivity and specificity of their procedures. The panel included 13 positive controls and 7 negative controls. The laboratories used either in-house PCR techniques adapted from the literature or partly standardized commercial tests. Three laboratories performed faultlessly with the entire panel. Most laboratories had excellent specificity (100% in 20 of 22 laboratories). Sensitivity was acceptable (85 to 100%) in 15 centers and insufficient (38 to 77%) in 7. As with nonstandardized in-house PCR, the commercial assays gave discrepant performances in different laboratories. These results suggest that laboratories willing to use PCR for detection of GBV-C/HGV RNA for research or diagnostic purposes should participate in multicenter quality control trials.

Flaviviridae↗