Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “quality control”

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 1,189 records · Page 66Linked to original sources
PubMed1999

Intra- and postoperative quality control in minimally invasive direct coronary artery bypass (MIDCAB) surgery.

The introduction of new techniques allowing direct coronary artery revascularisation without sternotomy and extracorporeal circulation--called Minimally (or less) Invasive Direct Coronary Artery Bypass grafting (MIDCAB)--has opened up interesting perspectives for the treatment of patients with limited coronary artery disease. However, like any newer surgical technique, this approach to myocardial revascularisation requires a critical appreciation of the results which may be obtained; when introducing the MIDCAB technique in our institution we developed a quality control protocol based on intraoperative as well as early and late postoperative parameters. This protocol is designed to detect every significant adverse event, exercise capacity and quality of life of our patients. Moreover, several invasive parameters have to be recorded in the protocol, such as intraoperative flow in the internal mammary artery conduit, the angiographic verification of anastomotic patency at one-year follow-up and determination of coronary flow reserve. The results of the first 5 patients observed up to one year postoperatively are presented: all anastomoses were patent and the flow within the internal mammary artery was 69 +/- 40 ml/min at one-year follow-up angiography; this compares very favourably with the flow measured at the end of the operation, which was 31 +/- 8 ml/min. This demonstrates very clearly that internal mammary artery flow is recruitable and usually significantly increases within the first months postoperatively. Coronary flow reserve was 3.4 +/- 1.1 (normal value > 2.5). The results obtained in this pilot study, which was designed to establish a quality control protocol, are very satisfactory and confirm previous experience that this technique may be offered to selected patients with appropriate coronary anatomy.

Coronary Artery Bypass↗
PubMed2004

Activation of mammalian unfolded protein response is compatible with the quality control system operating in the endoplasmic reticulum.

Newly synthesized secretory and transmembrane proteins are folded and assembled in the endoplasmic reticulum (ER) where an efficient quality control system operates so that only correctly folded molecules are allowed to move along the secretory pathway. The productive folding process in the ER has been thought to be supported by the unfolded protein response (UPR), which is activated by the accumulation of unfolded proteins in the ER. However, a dilemma has emerged; activation of ATF6, a key regulator of mammalian UPR, requires intracellular transport from the ER to the Golgi apparatus. This suggests that unfolded proteins might be leaked from the ER together with ATF6 in response to ER stress, exhibiting proteotoxicity in the secretory pathway. We show here that ATF6 and correctly folded proteins are transported to the Golgi apparatus via the same route and by the same mechanism under conditions of ER stress, whereas unfolded proteins are retained in the ER. Thus, activation of the UPR is compatible with the quality control in the ER and the ER possesses a remarkable ability to select proteins to be transported in mammalian cells in marked contrast to yeast cells, which actively utilize intracellular traffic to deal with unfolded proteins accumulated in the ER.

Activating Transcription Factor 6↗
PubMedDate not supplied

A comprehensive internal quality control system for a large cytology laboratory.

The British Columbia Cervical Cytology Program is operated through the Central Laboratory at the Cancer Control Agency in Vancouver and processes all of the gynecologic Papanicolaou smears collected by 3,200 physicians throughout the province of British Columbia. The laboratory receives approximately 2,400 smears per day, and the program currently processes in excess of 500,000 smears annually. This article describes the methods that have been developed for ensuring that adequate quality control is present in the screening and interpretation of half a million smears per year, both at the cytotechnologist and at the cytopathologist level. The results of the quality control program, which was considerably modified in 1985, are also presented. The modified program shows a significant improvement in the number of undercalled and overcalled cases detected in two comparable six-month periods.

British Columbia↗
PubMed1991

EORTC joint ventures in quality control: treatment-related variables and data acquisition in chemotherapy trials.

In multicentre studies, non-compliance with the protocol may limit the chances of reaching a correct conclusion. A procedure to examine the administration of chemotherapy in multicentre EORTC protocols has been developed. General aspects are covered in a mailed questionnaire on the prescription of drugs with rounding up or down of dosages, local facilities for preparation and the procedure for preparation and administration. More detail is collected during a quality control site visit. Ten centres have been visited and there was significant variation between centres in the organisation of chemotherapy administration. However, more striking differences were noted between the type and quality of hospital files. The lack of systematic recording of sequence, timing and doses of chemotherapy and, in particular, treatment related toxicity, is a major difficulty limiting the effectiveness of quality control. These shortcomings emphasise the need for standardisation of some aspects of case records and a suggested check-list has been drafted.

Antineoplastic Agents↗
PubMed1995

Practical guides. II: Hospital pharmacy quality control services.

This article briefly reviews the evolution, scope and operation of hospital quality control (QC) services. Recent initiatives and developments are considered alongside the traditional 'core' QC/quality assurance (QA) work. Important new areas of work which could benefit from QC involvement are also discussed.

Guidelines as Topic↗
PubMed1980

Commercially available blood-gas quality controls compared with tonometered blood.

We compared three commercially supplied blood-gas quality control solutions ("contrIL," "G.A.S.," and "Quantra") and tonometered whole blood under research and service conditions in four hospital laboratories. In some situations Quantra and tonometered blood were comparably sensitive to problems with blood-gas instrument malfunctions (e.g., hydraulics or temperature control) but the aqueous buffer-based materials were less sensitive. Within-day precision for all control materials was similar. The precision of pCO2 determinations in long-term studies was also similar for all control materials, as were pH determinations on commercial controls. For pO2 (especially at O2 < 50 mmHg), sample handling technique influenced the precision and accuracy of Quantra more than the other materials. The variability in pO2 determination with Quantra seems primarily to result from sensitivity in incubation temperature (3% change per degree C at 145 mmHg and 7% change per degree C at 43 mmHg). This study identifies some of the limitations of blood-gas control materials per se and some limitations related to specific blood-gas instruments that affect interpretation of results from them.

Blood Gas Analysis↗
PubMed2006

Molecular chaperones and protein quality control.

In living cells, both newly made and preexisting polypeptide chains are at constant risk for misfolding and aggregation. In accordance with the wide diversity of misfolded forms, elaborate quality-control strategies have evolved to counter these inevitable mishaps. Recent reports describe the removal of aggregates from the cytosol; reveal mechanisms for protein quality control in the endoplasmic reticulum; and provide new insight into two classes of molecular chaperones, the Hsp70 system and the AAA+ (Hsp100) unfoldases.

Adenosine Triphosphate↗
PubMedDate not supplied

[Dosimetric quality control in stereotactic radiotherapy with the aid of radiosensitivity].

Typical dosimeters used in stereotactic radiation therapy, such as ionization chambers, films, and thermoluminescent diodes, allow basic physical measurements. They are, however, neither well suited to discern small target volumes with high dose gradient, nor suitable for three-dimensional (3D) dose measurements. Gel dosimetry is becoming more and more interesting, owing to magnetic resonance imaging (MRI). It permits isocenter position planning verification of accuracy and the precision of the 3D dose mapping in the brain (when irradiated in realistic conditions), especially when several different targets are concerned. Many authors have assessed stereotactic radiation therapy quality control using different gels, and different irradiation procedures. This paper consists of the review of these different methods to assess quality control. Gel dosimetry cannot provide absolute dose measurements. However, gels can be used to check the 3D dose mapping with a high degree of detail. In our experiment, the difference between the stereotactic frame center and the isocenter is about 1 mm. The difference between the theoretical isodoses obtained by the treatment planning system and the experimental isodoses obtained by the MRI gray level calibration is also about 1 mm, the order of magnitude of the MRI pixel size.

Gels↗
PubMed1978

[Standardized protocol for radioimmunoassay evaluation and quality control (author's transl)].

Of several methods for constructing a radioimmunoassay (RIA) standard curve discussed in this paper the logit-log transformation emerges as the most favourable approach. In our hands, all RIA systems analyzed so far display a linear dose-response relationship after logit-log transformation. Truncating the standard curve to its operative range between effective dose 85 and 15, linear regression analysis can also be performed with the unweighted data, thus considerably facilitating computation. A standardized concept for RIA evaluation and quality control has been developed which can be executed by a low-cost desk-top calculator. A standardized protocol for RIA analyses should include the determination of total radioactivity added, the amount of both non-specifically and maximally-bound tracer hormone, 6 logarithmically-diluted standards specially prepared to cover the range between ED 85 and 15 and control samples with different levels of analyte. The RIA standard curve should be described by appropriate numerical parameters to keep a record of the intrinsic assay performance quality. Within assay variance is found on the basis of dose scatter of all unknown run in replicate, while between assay variance is based upon the observation of control sample variability. Control charts should graphically exhibit the variation of both essential assay parameters and control samples. Quality control should mainly be regarded as a means to assist in assay optimization which obviously is an important prerequisite for international standardization of RIA analyses.

Analysis of Variance↗
PubMed1986

Quality control aspects of blood pressure measurements in the Multiple Risk Factor Intervention Trial.

Quality control of an ongoing study of blood pressure must be an active, dynamic process in which attempts are continually made to reduce error and bias and maintain comparability among clinics. Training is an important means of initiating and maintaining proper procedures. In addition, changes in procedures during the trial must be properly evaluated so that their impact upon the conduct of the trial is known and, if necessary, quantifiable. The monitoring of quality measurement of blood pressure in a large clinical trial such as MRFIT must be a two-pronged effort that considers observation and evaluation of methods of measuring blood pressure in actual clinical practice and evaluation of data resulting from these procedures.

Allied Health Personnel↗
PubMed1979

The selection, acceptance testing, and quality control of radiotherapy treatment simulators.

The critical aspects of selection, acceptance testing, and quality control of a radiotherapy treatment simulator are discussed. The selection of a simulator involves consideration of: (a) motions and readouts, (b) safety features, (c) x-ray and imaging systems, and (d) mechanical tolerances (including guarantees). When considering motions, it is important to ascertain the extent of each motion, motorization and speed, control location, and the location accuracy, and type of scale. Important questions in x-ray system selection concern (a) x-ray generator ratings and phase, and (b) details of the x-ray tube and image intensification system.

Humans↗
PubMed2004

Protein folding and quality control in the endoplasmic reticulum.

The endoplasmic reticulum (ER) is a highly versatile protein factory that is equipped with chaperones and folding enzymes essential for protein folding. ER quality control guided by these chaperones is essential for life. Whereas correctly folded proteins are exported from the ER, misfolded proteins are retained and selectively degraded. At least two main chaperone classes, BiP and calnexin/calreticulin, are active in ER quality control. Folding factors usually are found in complexes. Recent work emphasises more than ever that chaperones act in concert with co-factors and with each other.

Animals↗
PubMed1986

Preserved blood versus patient data for quality control--Bull's algorithm revisited.

A comparison of the Bull's algorithm (XB) for quality control with a system based on analysis of preserved blood suggested that the preserved blood approach was the more sensitive method. However, the procedures compared were not equivalent. Four control blood samples analyzed by a multirule Shewhart approach were compared with a single XB result. Consequently, a reexamination of the relative sensitivities of the two methods was undertaken with a multirule Shewhart approach applied to both methods. On this basis, both methods have equivalent sensitivity. Once the XB mean reflects the shifted mean (and at all times with a drifting mean), either the XB algorithm or the analysis of preserved blood will detect systematic errors with similar probability using similar control rules.

Blood Preservation↗
PubMed2006

Multicenter quality control of the detection of HIV-1 genome in semen before medically assisted procreation.

Couples in whom the man is HIV-1-positive may use medically assisted procreation in order to conceive a child without contaminating the female partner. But, before medically assisted procreation, the semen has to be processed to exclude HIV and tested for HIV nucleic acid before and after processing. The performance was evaluated of the technical protocols used to detect and quantify HIV-1 in 11 centers providing medically assisted procreation for couples with HIV-1 infected men by testing panels of seminal plasma and cells containing HIV-1 RNA and/or DNA. The performance of these tests varied due to the different assays used. False positive results were obtained in 14-19% of cases. The sensitivity for RNA detection in seminal plasma was 500-1,000 RNA copies/ml, over 500 RNA copies/10(6) cells in semen cells, and for DNA detection in semen cells 50-500 DNA copies/10(6) cells. The use of silica-based extraction seemed to increase the assay performance, whereas the use of internal controls to detect PCR inhibitor did not. This first quality control highlights the need for technical improvements of the assays to detect and quantify HIV in semen fractions and for regular evaluation of their performance.

DNA, Viral↗
PubMed2003

Quality control of a national bone marrow donor registry: results of a pilot study and proposal for a standardized approach.

Unrelated hematopoietic stem cell transplantation (HSCT) is a recognized therapy for hematological diseases and over 8 million HLA-typed donors are ready to donate. Increased international exchanges and rapid requests through the Bone Marrow Donor Worldwide (BMDW) ask for standardized quality assurance. Since no such standards have been established to date, we tested a pilot program in order to evaluate donor availability and quality of HLA typing of the Swiss Registry. The 18500 donors of the registry have been analyzed by serology for HLA-AB and by molecular typing for HLA-DR. Through three successive annual quality control (QC) exercises, a total of 114 donor requests were sent to 13 blood transfusion centers responsible for donor recruitment asking for a blood sample. Donors were randomly selected according to recruitment periods (1988-1993; 1994-1997; 1998-2000), and to homozygosity for HLA-A and/or -B antigens. An additional 80 frozen blood samples from the repository corresponding to the three periods (n=26) and to the 2001 period (n=54) were also included in the HLA study. HLA-AB typings were done by polymerase chain reaction-sequence specific primers (PCR-SSP) and all discrepancies were retyped. The results showed that 79 samples provided by 69.3% of the requested donors were received within 14 days, and 19 samples (16.7%) were received in >14 days. Altogether, an 86% rate of donor availability was observed, independent of the recruitment period. Among the requested donors, 16 (14%) were not available: for medical reasons (two), for personal reasons (eight), for loss (one), and for an unknown reason (five). The HLA-A/B DNA typing results of 166 homozygous and 12 heterozygous blood samples showed that 437/439 (99.5%) of the assigned A/B antigens were correct. However in 36/178 donors (20.2%) an HLA-A or -B antigen had been missed (34 donors) or misassigned (two donors) by serology, with a decreasing discrepancy rate of 30% (1988-1993) to 18.5% in 2001. Assuming that HLA-A or -B homozygotes are found in 10-15% of the donors and that correct assignments have been observed in nearly 100% of the donors, an overall error rate of 4-5% would be expected for the national registry HLA-AB typing. These data show that standardized quality control for donor availability and HLA typing is feasible, and we propose that this model could be applied to the registries participating in bone marrow donor worldwide.

Bone Marrow Transplantation↗
PubMed1996

Implementation of internal laboratory quality control procedures for the monitoring of ELISA performance at a regional veterinary laboratory.

Quality control (QC) procedures for antigen detection enzyme-linked immunosorbent assays (ELISAs) for hog cholera (HC) virus, foot and mouth disease (FMD) virus, and an antibody detection ELISA for FMD virus were established at a regional veterinary laboratory in northern Thailand. A recently developed computer software package, QCEL, was used to facilitate management and analysis of QC data. The program was used to assess test performance by producing Shewhart-CUSUM control charts which monitored control data for unacceptable fluctuations or trends. QCEL-generated control charts and analyses are presented and discussed. The use of a simple integrated computerised system for storage and analysis of QC control data provided the laboratory with the opportunity to achieve increased confidence in the results of tests performed.

Animals↗
PubMed2002

Regulation and quality control of herbal drugs in Korea.

Korea has a great diversity in resources of medicinal plants. The traditional herbal medicines and their preparations have been widely used in Korea as well as in China and Japan for thousands of years. One of the characteristics of Korean herbal medicine preparations is that all the herbal medicines are incorporated into an extractor at the same time and extracted with boiling water during the decoction process. In this process, a variety of interactions between the active components of several herbal medicines may occur. This is the main reason why quality control of oriental herbal drug is more difficult than that of western herbal drug. In this paper, we would like to present an overview of the characteristics of regulation and quality control of herbal medicines in Korea.

Drug Industry↗