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PubMed2007

Quality control and validation.

This chapter discusses two important aspects of the structure determination process that are related to the accuracy and reliability of the crystallographic model under investigation. Quality control is defined as the analysis of an intermediate model to identify aspects of it that are unusual in some sense and that could, therefore, be a result of errors in the model building or refinement process. Any such errors need to be fixed, if at all possible, prior to analysis and publication of the model. Validation is the process of assessing the reliability of the final model (or certain aspects of it, e.g., the active site residues) that is about to be analyzed, published, deposited, and possibly used in follow-up studies.

Algorithms↗
PubMed2004

[Animal experiments in the context of quality control of pharmaceuticals. Review of the European Pharmacopoeia, 4th edition, 2002].

In the 4th edition of the European Pharmacopoeia, animal experiments are described, which are required for the quality control of pharmaceuticals. This refers to investigations regarding both biological activity and safety aspects of the medication. The latter include investigations to find contaminations with histamine and pyrogenic substances and tests for abnormal toxicity. Even though the safety of medical drugs is of great importance, it should be examined whether these tests are still indispensable (in terms of paragraph sign 7 of the German Animal Protection Law of 2002). The determination of histamine content may also be possible by chemical-analytical methods, which could represent an alternative to the animal experiment. The testing of abnormal toxicity should be scientifically questioned due to its lack of specificity. Although the in vitro test detecting bacterial endotoxins is mentioned in many monographs, the in vivo test on rabbits to test for pyrogenicity is still mentioned in some other monographs. The in vivo test should be rechallenged as to whether it can be replaced. In light of the global trade in pharmaceuticals, which must also fulfill national quality standards a reduction in animal experiments can only be reached by fruitful cooperation between pharmaceutical companies, health authorities and the commissions of the pharmacopoeias, leading to the formation of a consensus. The International Conference on Harmonization could prove an auspicious panel to take up this subject and to contribute to an internationally accepted and scientifically based reduction of animal experiments.

Animal Testing Alternatives↗
PubMed1992

[Quality control of the vaccines and cold chain during the national vaccination campaigns].

During the two vaccination campaigns against rinderpest and contagious bovine pleuropneumonia (CBPP) in 1989 and 1990, 507 vaccine samples were collected for quality control at each step of the distribution chain from the Veterinary Pharmacy of Abidjan to the vaccinator on the field. Parallel to that, the quality of the cold chain was checked. A total of 463 titrations were performed. All the titration levels were above the OIE/FAO standards, i.e. 10(2.5) DICT50/ml for rinderpest Valence and 10(7) viable germs/ml for contagious bovine pleuropneumonia Valence.

Animals↗
PubMed1996

Quality control of histamine and methacholine in diagnostic solutions with capillary electrophoresis.

Solutions of histamine and methacholine bromide in different matrices for diagnostic purposes were analyzed for stability and quality control using capillary electrophoresis. Histamine (2,[4-imidazolyl]ethylamine) [CAS No. 51-45-6] was determined using a 0.1 M Tris-borate buffer of pH 8.3 with 5.10(-5) M cetyltrimethylammonium bromide (CTAB) and 0.005% poly(vinyl alcohol) (PVA) and detected at 214 nm using clenbuterol [4-amino-alpha-(tert.-butylaminomethyl)-3,5-dichlorobenzyl alcohol] [37148-27-9] as an internal standard. Metacholine bromide (acetyl-beta-methacholine bromide) [333-31-3] was determined with a 0.01 M creatinine-chloride buffer of pH 4.85 and detected with indirect UV at 230 nm using potassium as an internal standard. Histamine solutions were stable for a prolonged period of time, whereas under enforced degradation conditions methacholine was hydrolyzed, yielding acetic acid and (tentatively) beta-methylcholine as reaction products.

Drug Stability↗
PubMed2000

Quality control guidelines for disk diffusion and broth microdilution antimicrobial susceptibility tests with seven drugs for veterinary applications.

This multicenter study proposes antimicrobial susceptibility (MIC and disk diffusion methods) quality control (QC) parameters for seven compounds utilized in veterinary health. Alexomycin, apramycin, tiamulin, tilmicosin, and tylosin were tested by broth microdilution against various National Committee for Clinical Laboratory Standards (NCCLS)-recommended QC organisms (Staphylococcus aureus ATCC 29213, Enterococcus faecalis ATCC 29212, Streptococcus pneumoniae ATCC 49619, Escherichia coli ATCC 25922, and Pseudomonas aeruginosa ATCC 27853). In addition, disk diffusion zone diameter QC limits were determined for apramycin, enrofloxacin, and premafloxacin by using E. coli ATCC 25922, P. aeruginosa ATCC 27853, and S. aureus ATCC 25923. The results from five or six participating laboratories produced >/=99.0% of MICs and >/=95.0% of the zone diameters within suggested guidelines. The NCCLS Subcommittee for Veterinary Antimicrobial Susceptibility Testing has recently approved these ranges for publication in the next M31 document.

Aminoglycosides↗
PubMed1991

Quality control in the laboratory diagnosis of tuberculosis.

The study was conducted in 4 hospital laboratories to assess the value of smear re-examination, duplicate smear and culture in quality control in the diagnosis of pulmonary tuberculosis. In each hospital 1 to 3 sputum specimens were collected from each suspect and examined by the Ziehl-Neelsen method. Smears along with corresponding specimens were sent to the reference laboratory for re-examination and examination of fresh duplicate smears and culture. A total of 994 specimens plus 23 known negative and 23 known positive controls were analysed. For each assessment method, both over-diagnosis and underdiagnosis were indicated with under-diagnosis being a more common problem in the four hospital laboratories. The limitations of these assessment methods are presented.

Evaluation Studies as Topic↗
PubMed1996

Quality control guidelines for National Committee for Clinical Laboratory Standards--recommended broth macrodilution testing of ketoconazole and itraconazole.

Ketoconazole and itraconazole were tested in a multilaboratory study to establish quality control (QC) guidelines for yeast antifungal susceptibility testing. Two isolates that had been previously identified as QC isolates for amphotericin B, fluconazole, and flucytosine (Candida parapsilosis ATCC 22019 and Candida krusei ATCC 6258) were tested in accordance with the National Committee for Clinical Laboratory Standards M27-P guidelines. Each isolate was tested 20 times with the two antifungal agents in the five laboratories by using a lot of RPMI 1640 unique to each laboratory as well as a lot common to all five laboratories, thus generating 200 MICs per drug per organism. Overall, 96 to 99% of the MICs for each drug fell within the desired 3-log2 dilution range (mode +/- 1 log2 dilution). By using these data, 3-log2 dilution QC ranges encompassing 98% of the observed MICs for three of the organism-drug combinations and 94% of the observed MICs for the fourth combination were established. These QC ranges are 0.064 to 0.25 micrograms/ml for both ketoconazole and itraconazole against C. parapsilosis ATCC 22019 and 0.125 to 0.5 micrograms/ml for both ketoconazole and itraconazole against C. krusei ATCC 6258.

Antifungal Agents↗
PubMedDate not supplied

Microbiologic quality-control study for the purpose of extending the use of transfer sets on the automix 3 + 3 and micromix automated total nutrient admixture compounding pumps.

BACKGROUND: A quality-control study was undertaken by the departments of pharmacy and microbiology at St. Paul's Hospital (Vancouver, British Columbia, Canada) to evaluate the microbiologic safety of total nutrition admixtures (TNA) compounded by automated compounding pumps when the use of disposable transfer sets was extended from 1 day to 2 days. This study also evaluates the potential annual cost savings of this extended use. METHODS: Transfer sets and unused part containers of ingredients were left to sit overnight on the automated compounders after daily TNA manufacturing before a TNA sample was compounded for culturing. These TNA samples were cultured using a biphasic system consisting of a tryptic soy broth component and an agar slide component. Positive results were subcultured and isolates were identified by standard methods. Forty samples were collected and evaluated. RESULTS: Four bags grew Bacillus species, and 1 bag grew coagulase-negative staphylococci. The potential annual cost savings of this extended use was estimated to be approximately 35,000 Canadian dollars. CONCLUSIONS: The extended use of the disposable transfer sets cannot be instituted at the present time and should be reexamined when the cause(s) of the positive results are identified and corrected.

Bacillus↗
PubMed2004

Quality control of MHC class I maturation.

Assembly of MHC class I molecules in the ER is regulated by the so-called loading complex (LC). This multiprotein complex is of definite importance for class I maturation, but its exact organization and order of assembly are not known. Evidence implies that the quality of peptides loaded onto class I molecules is controlled at multiple stages during MHC class I assembly. We recently found that tapasin, an important component of the LC, interacts with COPI-coated vesicles. Biochemical studies suggested that the tapa-sin-COPI interaction regulates the retrograde transport of immature MHC class I molecules from the Golgi network back to the ER. Also other findings now propose that in addition to the peptide-loading control, the quality control of MHC class I antigen presentation includes the restriction of export of suboptimally loaded MHC class I molecules to the cell surface. In this review, we use recent studies of tapasin to examine the efficiency of TAP, the LC constitution, ER quality control of class I assembly, and peptide optimization. The concepts of MHC class I recycling and ER retention are also discussed.

ATP-Binding Cassette Transporters↗
PubMed1990

[Registration of problems during anesthesia. Analysis of risk factors and quality control].

Society continues to increase its demands on the medical profession in regard to quality. We believe this situation should be met by a more systematic approach to risk evaluation and quality assessment of our work. We report an attempt to establish a routine system for recording complications during anesthesia. We included all 14,735 patients who were anesthetized during one year. Data on preoperative disease, type of anesthesia and operation, and problems encountered during anesthesia were recorded on the routine anesthesia chart. An arbitrary scale from 1-3 indicated the severity of the problem. Postoperatively, data from each patient were fed into a personal computer. The system is feasible in a busy clinical setting. Key problems are work discipline, exact criteria for complications, and quality control of anesthesia charts. 655 problems were recorded in 599 patients. 80 problems were very serious. Problems such as drop in blood pressure, intubation, laryngeal spasm and cardiac arrhythmias dominated. Such registration increases awareness for the safety of the patients, and enables us to assess the risk and evaluate the quality of our work. The system is now an integral part of the department's routine.

Adolescent↗
PubMedDate not supplied

[Experience in developing and introducing a system of defect-free work as a stage in creating a complex system of production quality control].

An experience in working out and introduction of a system of failure-free performance work as one of the most important steps in creating a complex system for the production quality control at the Leningrad combine "Krasnogvardeets" is described. Issues related to elaborating, introduction and further improving the system of the failure-free work, its pecuniary stimulation and setting up standards for the enterprise are discussed. Under consideration are also problems of organizing a unitized service for the quantity control, as an organ called to secure coordination and quidance over these operations at the combine in this industry.

Medical Laboratory Science↗
PubMed2003

Modified CMI, an essential adjunct to CMI of platelet for quality control during preparation and storage of platelet concentrates.

Changes in platelet indices such as platelet count (PLT), mean platelet volume (MPV) and corrected morphological index (CMI) have been correlated with the quality of platelet concentrates during storage but the acceptability criteria for these is not clearly defined. Platelet distribution width (PDW) is a measure of platelet anisocytosis and together with the MPV provides an adjunctive measure of quality. Hence, we investigated the use of the MPV and PDW with and without EDTA in an assessment of the quality of stored platelet concentrates. The differences in platelet count (dPLT), in MPV (dMPV) and in PDW (dPDW) with and without EDTA incubation were calculated. CMI and the modified CMI were further derived using dPLT, dMPV, and dPDW by simple mathematical calculations. We observed a good correlation of the CMI and modified CMI (r=0.966, p<0.01). The dPDWs underwent significant changes during the storage period in addition to changes in dPLT and dMPV. The dPDW provides a test of good power when compared with the dMPV (R(2)=64.1 and 26.1 respectively). We have observed an increment of 92.76% in the dPDW while it was 71% in the dMPV. This clearly shows that the dPDW is a better marker of quality control when compared to the dMPV during processing and storage of platelet concentrates.

Biomarkers↗
PubMed1977

Quality control in clinical chemistry: the two-sample plot and improvement of laboratory performance.

A two-sample plot is often used to display test results in clinical chemistry external quality control programs. The use of control materials at different concentrations calls for a re-evaluation of the two-sample plot. A modification of the two-sample plot is presented. The axes of the graph are graduated in units of measurement rather than standard deviation intervals. The mean of all laboratories or a reference laboratory's value is entered as the target value. For each laboratory, repeated results for the same or similar control materials are recorded. Visual inspection of the graph gives immediate information as to the extent of intra-laboratory variability, the incidence of systematic errors in the laboratory, and the size and type of systematic errors (proportional or constant) with respect to the target value.

Chemistry, Clinical↗
PubMed1997

Quality control of CGH: impact of metaphase chromosomes and the dynamic range of hybridization.

With the recent rapid expansion in the use of the comparative genomic hybridization (CGH) technique, increased attention to quality control is essential. In the present study, we show that despite optimization and standardization of metaphase preparation techniques and the commercial availability of metaphase spreads, batch-to-batch variability of the preparations remains a significant problem. To facilitate reliable CGH analysis despite this variability, we have developed a rapid denaturation test to assess the quality of the preparations without hybridization and quantitative image analysis criteria for assuring the day-to-day quality of CGH experiments, including sensitivity, specificity, and dynamic range. Monitoring the dynamic range of the hybridizations was found to be particularly critical for achieving sensitive and reliable CGH results. This reliability can be achieved, for example, by hybridization of a green-labeled normal male DNA against red-labeled female DNA and monitoring of the green:red ratio of the X chromosome in relation to that of the autosomes.

Chromosome Banding↗
PubMed1980

Quality control of 99mTc-radiopharmaceuticals. Evaluation of GCS minicolumns in routine clinical work with scintillation cameras.

Gel chromatography columnm scanning (GCS) is a rapid and reliable method for the quality control of 99mTc-radiopharmaceuticals. With this method the labelled compound and various impurities such as free pertechnetate, hydrolyzed reduced technetium or other 99mTc-complexes are obtained in one testing procedure. Using minicolumns results can be obtained with a simple testing procedure within a few minutes after the sample is taken; this is significant in routine radiopharmaceutical work. The resolution of the recording system is important, so as to be able to utilize fully the good separation ability of the minicolumn. Minicolumns were studied with some commonly used radiopharmaceuticals. A scintillation camera was used to record minicolumn data under various conditions and the results were conpared to those obtained using a scanner to reveal optimal recording conditions for the scintillation camera.

Chromatography, Gel↗
PubMed1992

MIC quality control guidelines for Haemophilus susceptibility tests using cefdinir (FK482), cefepime, cefetamet, cefpirome, ceftibuten, fleroxacin, temafloxacin, clarithromycin, RP59500, and trospectomycin.

A multilaboratory study was performed to establish broth microdilution MIC quality control (QC) guidelines for 10 investigational drugs which previously demonstrated significant activity against Haemophilus influenzae. MIC QC ranges for H. influenzae ATCC 49247 with Haemophilus test medium were determined by using multiple contemporary lots of Haemophilus test medium and the National Committee for Clinical Laboratory Standards' recommended numbers of replicate tests. On the basis of these results, QC ranges (generally modal MIC +/- one log2 dilution) are proposed for cefdinir, cefepime, cefetamet, cefpirome, ceftibuten, fleroxacin, temafloxacin, clarithromycin, RP59500, and trospectomycin. The proposed QC guidelines for clarithromycin and temafloxacin were recently accepted by the National Committee for Clinical Laboratory Standards.

Anti-Bacterial Agents↗
PubMed1996

[Quality control of intraoperative diagnosis].

A retrospective study of 2500 consecutive frozen sections obtained in the period April 14, 1993, through April 29, 1995 from the Institute of Anatomic Pathology of Ospedale "Bellaria" of Bologna is presented. The most frequent of mistakes followed sampling errors. Quality Control of frozen section diagnoses is a valid system for monitoring and improving the accuracy of diagnoses.

Diagnosis↗