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PubMed2006

A late-acting quality control process for mature eukaryotic rRNAs.

Ribosome biogenesis is a multifaceted process involving a host of trans-acting factors mediating numerous chemical reactions, RNA conformational changes, and RNA-protein associations. Given this high degree of complexity, tight quality control is likely crucial to ensure structural and functional integrity of the end products. We demonstrate that ribosomal RNAs (rRNAs) containing individual point mutations, in either the 25S peptidyl transferase center or 18S decoding site, that adversely affect ribosome function are strongly downregulated in Saccharomyces cerevisiae. This downregulation occurs via decreased stability of the mature rRNA contained in fully assembled ribosomes and ribosomal subunits. Thus, eukaryotes possess a quality-control mechanism, nonfunctional rRNA decay (NRD), capable of detecting and eliminating the rRNA component of mature ribosomes.

Down-Regulation↗
PubMed2001

Single bead characterization using analytical constructs: application to quality control of libraries.

Analytical construct technology has been successfully applied to the single-bead analysis of a split-mix combinatorial library. Substrates can be released from the resin by conventional cleavage for biological screening. Alternatively, for the purpose of analysis and quality control, cleavage at an orthogonal construct linker produces an analytical fragment incorporating the substrate. This analytical fragmnent is highly sensitized to electrospray mass spectrometry (ESI-MS) and is easily identified by isotope labeling. The construct cleavage rendered readily visible even those compounds that clearly could not be seen by conventional cleavage and mass spectrometry analysis. A 1H NMR control experiment proved that the compounds cleaved conventionally were, however, present in the sample in good yield and purity. In view of the data obtained, we think that this is a significant and important step toward solving our current quality control problems.

Amino Acids↗
PubMed2002

[Malignant skin tumours in a private dermatology practice. A quality control study].

BACKGROUND AND OBJECTIVE: The campaign for early detection of malignant melanoma and the increase in people with photodamaged skin have a remarkable influence on the daily dermatological routine. Could these factors lead to the introduction of quality control in a private dermatology practice? PATIENTS AND METHODS: Over a period of one year the diagnoses of all patients were registered. The clinical diagnosis of any skin tumour undergoing surgical removal was compared with the final histopathological diagnosis. RESULTS: 56% of 3004 diagnoses involved females; 44%, males. In 40.5%, the possibility of a pigmented or non-pigmented skin tumour was raised. 49% of the 291 tumours removed were malignant (107 basal cell carcinoma, 20 squamous cell carcinoma, 16 melanoma) while 11.7% were malignant precursor lesions. 48% of 44 melanocytic naevi with clinical atypia showed histopathological dysplasia but none were a malignant melanoma. No cancers were detected among 59 clinically benign tumors. In 71.8% of cases, the clinical diagnosis agreed with the result of the histopathological examination. CONCLUSIONS: This study shows, in concordance with literature, that a dermatologist can provide high quality treatment and prophylaxis of malignant skin tumours. With an optimal cost-performance ratio, he or she is the most competent partner for patients and health insurance companies.

Basal Cell Carcinoma↗
PubMed2003

Development of a LC method for pharmaceutical quality control of the antimetastatic ruthenium complex NAMI-A.

Imidazolium trans-tetrachloro(dimethylsulfoxide)imidazoleruthenium(III) (NAMI-A) is a novel ruthenium complex with selective activity against metastases currently in Phase I clinical trials in the Netherlands. Pharmaceutical quality control of NAMI-A drug substance and lyophilized product warranted the development of an assay for determination and quantification of NAMI-A and degradation products. A high performance liquid chromatography (HPLC) method was developed, consisting of a C18 column with 0.50 mM sodium dodecylsulfate in 3% methanol at pH 2.5 (acidified using trifluoromethanesulfonic acid) as the mobile phase and UV-detection at 358 nm. The HPLC method was proven to be linear, accurate and precise. Stress testing showed that degradation products were separated from the parent compound. By combining results of nuclear magnetic resonance (NMR) and HPLC experiments, one degradation product was identified as the mono-hydroxy species of NAMI-A. HPLC analysis with off-line detection of the eluate with flameless atomic absorption spectrometry (F-AAS) showed that under most conditions, all ruthenium-containing compounds show a peak in the HPLC chromatogram and that all ruthenium applied to the column is recovered quantitatively. For completely degraded solutions of NAMI-A some ruthenium is retained on the column. Suitability of the HPLC method for the pharmaceutical quality control of NAMI-A lyophilized product was demonstrated.

Antineoplastic Agents↗
PubMed1986

Use of patient data for quality control.

This article discusses how specific patient data algorithms can be used and optimized for laboratory quality control. These algorithms include delta checks, patient averages, and multivariate checks. With the increasing emphasis on cost containment, the intelligent use of these algorithms should become widespread.

Medical Records↗
PubMed2001

Quality control in the secretory assembly line.

As a rule, only proteins that have reached a native, folded and assembled structure are transported to their target organelles and compartments within the cell. In the secretory pathway of eukaryotic cells, this type of sorting is particularly important. A variety of molecular mechanisms are involved that distinguish between folded and unfolded proteins, modulate their intracellular transport, and induce degradation if they fail to fold. This phenomenon, called quality control, occurs at several levels and involves different types of folding sensors. The quality control system provides a stringent and versatile molecular sorting system that guaranties fidelity of protein expression in the secretory pathway.

Endoplasmic Reticulum↗
PubMed1989

[Quality control in emission-computed tomography].

The authors considered the major aspects of the control of the quality of computed emission tomography (SPECT), assessed the influence of the physicotechnical parameters of the instrument, parameters of recording of results and methods of their processing on end-results of investigations. The authors propose a list of controlled parameters, methods of testing and their periodicity; they also describe the techniques and results of some phantom studies using SPECT with the Jaszczak phantom.

Filtration↗
PubMed1980

[A system for quality control of biotransformation enzymes in the mucosa of small intestine (author's transl)].

A system for quality control of the determination of arylhydrocarbonhydroxylase (benzpyrenhydroxylase), ethoxycoumarin-O-deethylase, NADPH-cytochrom-c-reductase, epoxidehydrase and uridindiphosphoglucouronyltransferase was developed. We used lyophilized and frozen samples of postmitochondrial supernatant of rat and guinea pig small intestinal mucosa, which was prepared using a 1:5 ratio of mucosa to K-phosphate buffer. For NADPH-cytochrome-c-reductase, the microsomal suspension from rat small intestine was used. The samples were stored at -30 degrees C. The coefficient of variation within run was about 5% (15 samples), the coefficient of variation between run (15 days) about 10%. The control specimens were stable for 6 months.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1983

Analytical biases with liquid quality control material.

Biases were compared for eight analytes determined using common chemistry instruments. Data for three levels of liquid control sera were obtained from over 350 laboratories participating in a quality control program. These data were contrasted with comparable results for lyophilized material and reported in a CAP proficiency survey. In general, biases appeared to be proportional to analyte level. For some analytes, biases with liquid material were less than with lyophilized material, but for most analytes, biases were greater with liquid than lyophilized material. However, when liquid material is used for monitoring interlaboratory precision, the consequences of analytic biases are minimized because of large pool sizes.

Autoanalysis↗
PubMed2003

[Hospital infection surveillance and multiresistance monitoring: role of an external quality control].

The "Relais Régional d'Hygiène Hospitalière du Centre" (RHC) promotes the hospital infection prevention at a regional level in France, including 80 healthcare institutions. The accuracy of antimicrobial susceptibility data submitted by laboratories to surveillance is essential. Since 2001, RHC imposed an external quality control to validate the accuracy of the data submitted by the laboratories that are involved in survey programs. Most laboratories are able to detect homogenous methicillin resistance in S. aureus, and high-level vancomycin resistance in E. faecalis. Nevertheless, the ability of laboratories to detect organisms with emerging antimicrobial resistance patterns is not optimal for (i) detection of heterogeneous methicillin resistance, (ii) reduced susceptibility to teicoplanin in a non-multiresistant S. aureus and (iii) detection of resistance to extended-spectrum cephalosporins. Educational program to optimize the testing methods has been programmed and perennially of quality control testing prior to accepting data from laboratory participating in surveillance system is decided.

Cross Infection↗
PubMed2001

A survey of radiotherapy quality control practice in the United Kingdom for the START trial.

BACKGROUND AND PURPOSE: This paper compares the quality control checks performed in departments in the United Kingdom with those recommended by the Institute of Physics and Engineering in Medicine (IPEM) in Report 81. METHOD: The data were gathered by the quality assurance team for the START trial, during visits to individual departments. Data are compared with the frequencies suggested in IPEM report 81. Where applicable, data are also analyzed with respect to machine manufacturer. RESULTS: All departments with linear accelerators check the output at least weekly for both photons and electrons, however 11% of departments do not perform a constancy check of the output on a daily basis. The majority of departments check flatness at gantry zero on a monthly basis. However 27% of departments never check at non-zero gantry angles. In 51% of departments no fluoroscopy checks are performed on simulators on a daily basis. CONCLUSION: The majority of departments are following the frequencies suggested in IPEM report 81 although there are a number of discrepancies particularly for simulators. Accelerator type needs to be considered when designing quality assurance checks. In many departments more time than is currently allocated is needed on equipment, particularly simulators, to complete all of the checks suggested in Report 81.

Breast Neoplasms↗
PubMed1990

Blood film evaluations as a quality control activity.

Correlation of the blood film with the blood-count parameters provides a means of quality control of results obtained by the counter. This requires the observer to be skilled in identifying significant morphological abnormalities. Reliable blood film assessment must avoid potentially misleading information resulting from cell distribution bias and morphological artefact produced by poor techniques in the preparation and staining of films. Thus, whilst concordance between instrument results and manual films provides control on the sensitivity, specificity and predictive value of the counter, conversely blood count results provide a check on the reliability of the blood film. The experiences with the United Kingdom external quality assessment program illustrate the strengths as well as weaknesses of the blood film evaluation.

Hematologic Tests↗
PubMed1984

Medicare program; utilization and quality control peer review organizations; imposition of sanctions on health care practitioners and providers of health care services--HCFA. Proposed rule.

This proposal would implement the portion of the Peer Review Improvement Act of 1982 that imposes certain obligations on health care practitioners and other persons who provide health care services to Medicare beneficiaries. The proposal would also establish sanctions that the Secretary may impose for violations of the obligations. The proposal would also impose certain responsibilities on utilization and quality control peer review organizations and provides that an exclusion sanction recommended to the Secretary by utilization and quality control peer review organizations would automatically become effective if the Secretary fails to act within a 120-day review period. These regulations are intended to assure that the public receives medically necessary, quality health services.

Centers for Medicare and Medicaid Services, U.S.↗
PubMed1975

[Possibilities of a quality control in the diagnosis of tuberculosis (author's transl)].

A method is described which allows a quality control for demonstrating mycobacteria in the diangosis of tuberculosis. It does not test the differentiating procedures, but the manner of culturing and concentrating the bacteria by applying a statistical evaluation of serial experiments, thus allowing the statistically proven determination of the bacterial count. For this an evaluation method given by Cavalli-Storza was employed.

Bacteriological Techniques↗
PubMed1994

General principles of surgery quality control.

Randomized clinical trials are currently the most reliable research technique to generate reliable treatment data. Quality control and monitoring with statistical credibility are essential. This requires nurse data managers and coordinators and statisticians, as well as the surgeons and physicians. A well-structured operating infrastructure is key. From the surgical point of view, careful intraoperative staging and standardization of the surgical procedures are a must. Strict eligibility criteria must be documented and enforced. Finally, careful stratification for prognostic variables before randomization in phase 3 trials is essential.

Clinical Trials, Phase III as Topic↗
PubMed2002

Defects of a mammography quality control phantom visualized by synchrotron radiation imaging.

Synchrotron radiation (SR) imaging of an RMI 156 mammography quality control phantom, serial number 156-15330, revealed some defects which degraded the visibility of calcification specks. SR imaging was performed at SPring-8, in Harima, Japan by using a monochromatic energy of 20 KeV with a field-of-view of 24 X 24 mm. Different kinds of images were obtained by changing sample-to-detector distances; absorption images and refraction-enhanced images. Specks were embedded in a wax matrix and were imaged as black in an absorption image. In a refraction-enhanced image, they were imaged as a black region with white margins. Foreign objects with opposite contrast were detected near, or overlapped with, some specks. As they were depicted as white in the absorption images and as white with a black margin in the refraction-enhanced image, it seemed that they had low X-ray attenuation and a low refraction index compared with the surrounding wax. They might presumably be air bubbles. Visibility of specks in an absorption image was seriously interfered with when those object(s) overlapped with specks. This kind of defect may cause a difficulty in meeting quality assurance specifications when a facility inadvertently purchases defective phantoms.

Artifacts↗
PubMed1986

Radiographic quality control measurements comparing D-speed film, E-speed film, and xeroradiography.

This study evaluated quality control (QC) measurements of D-speed film, E-speed film, and xeroradiography under clinical conditions. Automatic and manual (wet-tank) film-processing techniques were assessed. The results of QC tests (speed index, contrast index, and base + fog measurements) indicated that D-speed film and E-speed film react similarly under clinical conditions with regard to speed and contrast when processed automatically. E-speed film had an elevated base + fog measurement over D-speed film in both processing methods. Manually processed D-speed film had a greater contrast than did manually processed E-speed film. Xeroradiography maintained a consistent level of image processing under clinical conditions during this 90-day trial.

Quality Control↗
PubMed1996

Reliability of nucleic acid amplification for detection of Mycobacterium tuberculosis: an international collaborative quality control study among 30 laboratories.

Nucleic acid amplification to detect Mycobacterium tuberculosis in clinical specimens is increasingly used as a laboratory tool for the diagnosis of tuberculosis. However, the specificity and sensitivity of these tests may be questioned, and no standardized reagents for quality control assessment are available. To estimate the performance of amplification tests for routine diagnosis, we initiated an interlaboratory study involving 30 laboratories in 18 countries. We prepared blinded panels of 20 sputum samples containing no, 100, or 1,000 mycobacterial cells. Each laboratory was asked to detect M. tuberculosis by their routine method of nucleic acid amplification. Only five laboratories correctly identified the presence or absence of mycobacterial DNA in all 20 samples. Seven laboratories detected mycobacterial DNA in all positive samples, and 13 laboratories correctly reported the absence of DNA in the negative samples. Lack of specificity was more of a problem than lack of sensitivity. Reliability was not found to be associated with the use of any particular method. Reliable detection of M. tuberculosis in clinical samples by nucleic acid amplification techniques is possible, but many laboratories do not use adequate quality controls. This study underlines the need for good laboratory practice and reference reagents to monitor the performance of the whole assay, including pretreatment of clinical samples.

Bacterial Typing Techniques↗