SEARCH · Search PubMed
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.
Glutaraldehyde-treated bacterial cells were used as the quality control organisms in agglutination and fluorescent antibody tests for group A Streptococcus; Salmonella groups A, B, and D; Shigella groups B, C, and D; and Neisseria gonorrhoeae. The antigen preparations were serologically reactive over a period of five months.
The success of any cooperative clinical trial is dependent on assuring that the data collected are of good quality. This requires that an extensive and detailed program be developed for assuring good quality performance of all participating centers. Procedures for monitoring the clinical centers and procedures for monitoring or assuring quality of data handling and processing in the coordinating center, i.e., procedures for monitoring the coordinating center, are discussed. The procedures described are based on experience in the Diabetic Retinopathy Study, which is completing data collection, and a new study, the Early Treatment for Diabetic Retinopathy Study, which is in the planning phase. Some of the principles will apply to any participating unit. As in all aspects of clinical trials, a quality control program requires attention to detail and careful planning and vigilance on the part of all participants.
The process of 'quality control' in the endoplasmic reticulum (ER) involves a variety of mechanisms that collectively ensure that only correctly folded, assembled and modified proteins are transported along the secretory pathway. In contrast, non-native proteins are retained and eventually targeted for degradation. Recent work provides the first structural insights into the process of glycoprotein folding in the ER involving the lectin chaperones calnexin and calreticulin. Underlying principles governing the choice of chaperone system engaged by different proteins have also been discovered.
With regard to the principles of replacement, reduction and refinement, art. 231 of the Council Directive 86/609/EEC on the Protection of Animals used for Experimental and other Scientific Purposes, is of utmost importance. This article states that "The Commission and Member States. would take steps. to encourage research into the development and validation of alternative techniques.". In order to carry into effect this article, the Commission of the European Communities (EC) has established the European Centre for the Validation of Alternative Methods (ECVAM) on October 29, 1991. The centre is located at the Joint Research Centre (DG XI) at Ispra (Italy), its first director is Michael Balls from the UK. The main goal of ECVAM is to promote the regulatory acceptance of alternative methods which are of importance to the biosciences and which reduce, refine or replace the use of laboratory animals. The activities of the centre are focused on facilitating, co-ordinating, supporting and/or organising international validation studies, preferably in collaboration with other bodies. A working program has been made for 1993 and 1994 by ECVAM"s scientific advisory committee. Animal testing in the quality control of vaccines was selected as one of the area"s of interest. As a first step it was decided to organise a workshop, with the aim to evaluate potential alternatives, to identify obstacles in development, validation and implementation and to discuss possible solutions. The workshop was held in Utrecht, April 16-17 and the 20 invited participants came from national control laboratories, regulatory bodies, vaccine manufacturers and academic world. (article in English) (The main conclusions and recommendations in the field of the quality control of veterinary vaccines have been published in ATLA 22, 420-434, 1994)
There is a final purpose of the standardization of the external quality control for the resolution of the difference between facilities. Two solutions are promoted in order to unify the evaluation level. They are that it unifies the reference value and common evaluation method used common display. However, it is the prior settlement that there is some a problem on both method and that absolute value is made to agree using standard substance.
The quality control of insulin radioreceptor assay for human erythrocytes is based on the storage of erythrocyte preparations in Hepes buffer of pH 8.0, containing 10 g/l of albumin and 20 mmol/l of glucose. The change of erythrocytes into spherocytes and crenated cells reduces the apparent number of insulin receptors in a relatively constant way by less than 8% a week after 10 days of storage. At the same time the dissociation constants of the insulin-receptor complex increase rapidly. Thus the use of a preparation must be limited to controlling the determination of the insulin binding sites of erythrocytes, and not to the measurement of the affinities of the receptors. When mono-125I-Tyr-A14-insulin gets old, a slow decrease in the insulin binding sites can be measured, but the dissociation constants of the insulin receptor complex are not affected.
Quality control of albumin solutions for human use is of utmost importance because the presence of impurities can provoke adverse reactions in treated patients. Three different techniques were used to detect the presence of albumin oligomers and polymers as well as foreign proteins in commercial solutions. The relative concentrations of the former two were estimated using size-exclusion high-performance liquid chromatography. Isoelectric focusing and two-dimensional immunoelectrophoresis allowed detection of other contaminants of proteinaceous nature. The application of this combination of techniques supersedes the traditional approaches (gel filtration on polydextran gels, electrophoresis) in specificity and speed. Analysis of 34 lots of commercial albumin solutions from 22 manufacturers revealed the superior quality of preparations of placental rather than plasmatic origin.
A simple computer program for the data processing and quality control of radioimmunoassays is presented. It is written for low cost programmable desk top calculator (Hewlett Packard 97), which can be afforded by smaller laboratories. The untreated counts from the scintillation spectrometer are entered manually; the printout gives the following results: initial data, logit-log transformed calibration points, parameters of goodness of fit and of the position of the standard curve, control and unknown samples dose estimates (mean value from single dose interpolations and scatter of replicates) together with the automatic calculation of within assay variance and, by use of magnetic cards holding the control parameters of all previous assays, between assay variance.
A set of X-ray test objects has been developed for quality control in digital subtraction fluorography (DSF). Factors which can be assessed include dynamic range, highlight overload and signal-to-noise ratio, low contrast sensitivity, unsharpness, and systematic misregistration. These test objects complement, both in design and calibration, those previously developed to evaluate the imaging performance of television fluoroscopy and small-format fluorography systems. In this article, the first of two, we describe the Leeds DSF test objects, paying particular attention to the reasoning behind their design.
High-performance liquid chromatography (HPLC) has been used in the routine quality control of immunoglobulin preparations to measure the contents of aggregates, dimers, monomers and degradation products. The correlation coefficients between TSK 3000 SW, Ultrogel AcA 34 and Sephacryl S-300 chromatography were calculated and a reasonable correlation was found. The decrease in the potency of anti-tetanus immunoglobulin at room temperature was accompanied by an increase in degradation products. The speed and high sensitivity of HPLC make it suitable for the detection of aggregates in intravenous immunoglobulin preparations.
A data acquisition and analysis protocol for quality control (QC) of functional magnetic resonance imaging studies is presented. Two sets of data are acquired, single-timepoint data for measurement of signal-to-ghost and signal-to-noise ratios, and multiple-timepoint data for measurement of short-term drift. Since manual data analysis can be time consuming and an impediment to regular QC, an automated data processing scheme is presented. The use of automated Shewhart charting is proposed to identify significant changes in each parameter over the long term. The protocol has successfully identified system faults and deteriorations undetected by conventional QC.
The anti-carcinoembryonic B2C114 monoclonal antibody was radiolabeled with 99mTc by a direct method and quality control tested in vitro by instant thin layer chromatography, gel column scanning and cellulose acetate electrophoresis and assessed in vivo for radioimmunodetection on a murine spontaneous mammary carcinoma. The optimal results of percent 99mTc bound to protein were obtained at a dithiothreitol:antibody molar ratio ranging from 800:1 to 1000:1 and at a methylene diphosphonate:stannous fluoride weight ratio of 4.3:1. Although cysteine removed up to 18% of the label during the first 4 h, the stability of the tracer appeared to be excellent in human serum at 37 degrees C and when challenged with DTPA. 99mTc-labeled B2C114 demonstrated good and specific in vivo tumor targeting.
The apparent current explosion of interest and commercial activity in the area of herbal products should be followed by accurate quality control. In this work, the authors carried out the specific quality assays of all the aromatic drugs reported in European Pharmacopoeia. For each drug, several samples of different brands were bought in pharmacies, herbalist's shops, or supermarkets. The worst results were obtained in the assay for the essential oil content and this is very negative as the medicinal activities of these drugs are ascribed to their essential oil content. The samples of different brands yielded very different results from a qualitative point of view. In most cases, the analyzed samples were very far from the acceptable qualitative standards that they definitely lacked any health benefits.
WHO oversees the quality control of BCG vaccine via a system that includes regular testing of products by in vitro methods and clinical trials. Three parent strains of BCG (Glaxo-1077, Tokyo-172, and Pasteur-1173P2) account for over 90% of the vaccines currently in use worldwide. Important characteristics of the vaccine preparations are summarized here, along with their physical-chemical properties. In instances where diagnostic criteria for tuberculosis are stringent, there is no evidence that when administered to newborns different preparations of BCG vaccine exhibit different efficacies; however, the incidence of BCG-associated adverse reactions does correlate with the type of preparation. Other factors, including dose, administration technique, and recipient characteristics are also important in determining vaccine-associated reactions.
Limitation of process change is a major factor contributing to assurance of quality in pharmaceutical manufacturing. This is particularly true in the manufacture of coagulation factor concentrates, for which presumptive testing for poorly defined product characteristics is an integral feature of finished product quality control. The development of new or modified preparations requires that this comfortable position be abandoned, and that the effect on finished product characteristics of changes to individual process steps (and components) be assessed. The degree of confidence in the safety and efficacy of the new product will be determined by, amongst other things, the complexity of the process alteration and the extent to which the results of finished product tests can be considered predictive. The introduction of a heat-treatment step for inactivation of potential viral contaminants in coagulation factor concentrates presents a significant challenge in both respects, quite independent of any consideration of assessment of the effectiveness of the viral inactivation step. These interactions are illustrated by some of the problems encountered with terminal dry heat-treatment (72 h. at 80 degrees C) of factor VIII and prothrombin complex concentrates manufactured by the Blood Products Laboratory.
The main goal of the present study is to develop an immunoanalytical method for the quality control of orange juice products. Peptides from various parts (juice, albedo, and flavedo) of citrus fruits (orange, mandarin, grapefruit, and lemon) were analyzed and isolated by SDS-PAGE. Antisera were developed in mice against the protein pool of orange juice and peel and tested by Western blot analysis. Using these antisera, some juice- and peel-specific peptides were detected. One of the antibodies in the antiserum developed against peel proteins recognized a single peel-specific peptide with a molecular mass of 28 kDa in 10000-fold dilution. It did not give any positive reactions against the sample prepared from the juice. The 24 and 27 kDa juice-specific peptides were isolated in electrophoretically pure form, and polyclonal antibodies were developed against them in mice. The anti-27 kDa antibody reacted with a 29 kDa protein in the peel sample, and it gave a positive reaction against the 27 kDa peptide of the juice. The antibodies developed in the course of the present work seem to be useful for determining the juice content in commercial citrus beverages and for evaluating the peel contamination in them.
The emergence of structure-determination initiatives that employ high-throughput protein crystallography emphasizes the need to establish quality-control methods for screening the resulting models prior to deposition with the public data banks. An in-house database of 26 new protein structures, associated diffraction data and high-quality experimentally determined electron-density maps have been used to develop (i) a set of minimal global quality criteria that a structure must meet before the refinement may be considered completed and (ii) a reliable set of indicators for detecting local errors in protein structures. These criteria have been applied to detecting local errors to a set of structures recently deposited in the Protein Data Bank and it is estimated that about 3% of amino acids are incorrectly modeled.
The aim of this study was to investigate the mini cartridge versus paper chromatography quality control methods for determining the radiochemical purity (RCP) of (99m)Tc-bicisate. The 4 methods that were compared with the manufacturer's method included Whatman 17 paper/ethyl acetate solvent, instant thin-layer chromatography (ITLC) silica gel paper/saline solvent, reverse-phase C18 mini cartridge/saline solvent, and strong anion exchange mini cartridge/water solvent. At 30 min after reconstitution, (99m)Tc-bicisate was formed at 97%-98% RCP as assayed by the paper and cartridge methods, and the strong anion exchange/water for injection (WFI) system slightly underestimated the percentage at 96%. A significantly lower RCP was obtained for the C18/saline method when a faster flow rate was used. The lipophilic complex moved with ethyl acetate on Whatman 17, was separated from origin impurities on ITLC silica gel/saline, and remained on the column with C18/saline. For strong anion exchange/WFI, components in the radioactive formulation are likely to have influenced the percentage of (99m)Tc-bicisate. The time disadvantage for ITLC silica gel/saline analysis made the method less than ideal. The C18 mini cartridge/saline method was found to be the simplest and fastest; a result was obtained in 2 min with use of a safe solvent of elution.