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A short history of the use of animals in vaccine development and quality control.

Man has been using animals since early times to gain an insight into health, illness and death. The oldest known medical standard work, the Corpus Hippocraticum (circa 350 BC), contains descriptions of experiments on pigs. Although the first attempt at immunoprophylaxis dates as far back as the 6th century (variolation was practised in China to protect people against smallpox), it was not until the middle of the 19th century that animal experimentation acquired full scientific status in the development and quality control of immunobiological products. It was Louis Pasteur and Robert Koch who, through studies on animals, succeeded in underpinning the causal relationship between infectious diseases and micro-organisms, thus opening the way to the discovery of effective therapeutic and prophylactic agents for a number of these diseases. In several respects, the experimental animal work carried out in the last decade of the 19th century to find an effective and reliable way of treating and preventing diphtheria determined the use of animals. Many common routine animal tests in the quality control of immunobiologicals arose from diphtheria research. Conversely, diphtheria was one of the first diseases where experimental animal research laid the foundation for effectively reducing child mortality. This had a very profound impact on the attitude of society towards animal experiments in those days and almost completely eliminated the growing influence of the antivivisection movement. The interest in the possibilities of replacement, reduction and refinement (the Three-Rs concept) of the use of laboratory animals is increasing for several reasons, including concern about animal welfare. The root of animal welfare can be traced back to the 18th century with the formulation of utilitarian ethics. One characteristic feature of these ethics was that the interests of any creature which is submitted to any procedure should be taken into consideration. This presentation sets out some major historical contributions of animal experiments to the development and quality control of immunobiologicals. Attention is also paid to the changing attitude of society towards animal experiments and its impact on the development of alternative methods. It is concluded that, although animal experiments have played an important part, a new area is now beginning in which increasing emphasis will be placed on in vitro methods.

Animal Testing Alternatives↗

Quality control in antimicrobial disk susceptibility testing: a Belgian multicenter study.

A Belgian multicenter trial was conducted to evaluate problems encountered with quality control results of antimicrobial disk susceptibility testing and to compare the performance of BBL disks and Rosco tablets. Over a period of four weeks 18 laboratories daily tested three reference strains against eight antibiotics. A standardised method was used by all participants. For all results together 10.4% and 7.3% of the measurements with BBL disks and Rosco tablets, respectively, were outside the recommended range. Major problems were observed for some specific strain-antibiotic combinations. Standard deviations were similar for both systems; their precision was comparable. The results suggest that cooperation between manufacturers and some reference laboratories could be improved in order to establish optimal quality control limits.

Anti-Bacterial Agents↗

Reduction of numbers of animals used in the quality control of biologicals.

Laboratory animals are used for the quality control of vaccines. In particular, the potency testing of batches of inactivated vaccine requires large numbers of animals. The possibilities for reduction have been evaluated, and the results are summarised in this paper. Several approaches were studied, including the retrospective analysis of test data, with the objectives of determining the minimum number of animals required per vaccine dilution group, and evaluating the feasibility of a single-dose potency test. Other studies focused on the development of serology-based models and the use of genetically uniform animals. Based on the outcome of these studies, a substantial reduction in the number of animals used for the potency testing of toxoid vaccines has been achieved or will be achieved in the near future. As reduction alternatives can generally be explored in a relatively simpler and less time-consuming way than replacement alternatives, more emphasis should be placed on reduction strategies than at present.

Animal Use Alternatives↗

Improvement in mammography quality control: 1987-1995.

PURPOSE: To assess possible changes in quality control (QC) practices at mammography sites in the United States. MATERIALS AND METHODS: Mammography site surveys were conducted in 1990, 1992, and 1995 through the Colorado Mammography Advocacy Project (CMAP). Data from mammography sites applying for American College of Radiology (ACR) accreditation were collected between August 1987 and August 1993 through the ACR Mammography Accreditation Program. Data from both of these surveys were analyzed to assess temporal changes in mammography QC practices in the United States between 1987 and 1995. RESULTS: CMAP results indicated statistically significant improvement in medical physicist QC practices between 1990 and 1992 and in technologist QC practices between 1990 and 1995. Improvements in radiologic technologist QC practices coincided with increases in radiologic technologist continuing education in mammography. ACR results indicated statistically significant improvement in technologist QC practices between 1988 and 1992. CONCLUSION: There have been substantial improvements in QC practices at mammography sites in the United States during the past decade.

Chi-Square Distribution↗

[Quality control of spirographic examinations in a health center].

A quality control of spirographic examinations in a health centre was carried out by repeating, after a fortnight's interval, measures of vital capacity (CV) and FEV1 (VEMS) in 629 subject of both sexes, aged 18 to 62. Water spirometers were used and their cylinders were regularly calibrated. The first series of spirographic measurements were made during a routine health check (which included other examinations) by 7 technicians who usually do the work, while the second series of measurements was made of fortnight later by the most experienced three. The overall mean values show a significant difference for vital capacity between the first and second measurement; this difference was so for young male subjects (less than 30 years). The scatter was greater for subjects over 50 years of age. The varied results observed for the same subjects obtained by two different technicians, or the same technician, underlines the fact that the scatter of the results depends largely on the technician even though spirographic tests are classically considered easy to perform.

Adolescent↗

A quality control program for cine radiography.

We describe a ciné processing quality control program aimed at the consistent production of high quality angiograms. A year's experience with this protocol has demonstrated the difficulty and importance of maintaining a constant on-frame optical density to ensure consistently high quality. We monitored film processing, speed of the emulsion and the automatic brightness control of the angiographic imaging system several times a day. Variations in film speed and their causes observed in our institution demonstrate that parameters other than film processing should be carefully controlled. The cost of applying this protocol is about +190.00/month and it requires no additional personnel. The cost is offset by the improved quality of the angiograms, reduced repeat examinations, and the improved monitoring of the system making for more effective preventative and corrective maintenance.

Cineangiography↗

Validation of bioassays for quality control.

For a biological assay to be useful for quality control it should fail bad lots, pass good lots, and estimate relative potency with high accuracy and precision. To fail a lot we rely most heavily on the test for parallelism. For the parallelism test and other preliminary tests as well as for inference, appropriate estimates of assay variation are crucial. Location effects on 96 well plates and serial dilution of samples using multichannel pipettes make it difficult to obtain good estimates of assay variation. This paper develops the use of a split-block design and analysis where blocks are reasonably consistent regions of a plate; this approach removes some location effects, allows other location effects to be treated as assay variation and provides appropriate measures of assay variation. Randomization, even within the split-block design, is difficult without robots to reduce the likelihood of procedural errors. There are hardware, software, and validation obstacles to implementation of robots in the bioassay laboratory. More generally, validation of a bioassay should be reported on log relative potency and must address between- and within-assay variation. When between assay variation is not small, the usual weighted approach to combining relative potency estimates (which ignores between-assay variation) is inappropriate; a simple sampling average and standard deviation is a better solution.

Biological Assay↗

RGP quality control: the results of a national survey.

BACKGROUND: Rigid gas permeable (RGP) contact lenses have numerous benefits; however, one of the possible problems of RGP lenses is variable quality that can result in reduced initial comfort and an unsuccessful fit. METHODS: A quality control survey was sent to 200 optometrists, selected at random, to provide information on lens usage, verification, use of reused or modified lenses, use of authorized laboratory, and to evaluate important laboratory characteristics. A total of 86 optometrists responded to the survey. RESULTS: The results indicated that most respondents fit between 10-25 percent of their new contact lens patients with RGPs. In addition, although both of these parameters can be extremely important to patient success, only 56 percent of the practitioners verify edge quality and even less, 38 percent, verify center thickness. Sixty-seven percent of the practitioners indicated that poor initial wettability occurred in, at minimum, 5-10 percent of all new lenses. 75 percent of the practitioners indicated that it would matter to them if the supposed new lenses had previously been used or modified. Finally, optical quality and lens parameter accuracy were considered much more important than turnaround time and material cost. CONCLUSIONS: It appears from these results that variance in quality control can result in compromised lens quality and performance. In addition, it can be reduced by more careful lens inspection by the practitioner. If careful attention is devoted to these recommendations, RGP lens use and success could increase accordingly.

Contact Lenses↗

Applying quality control charts to the analysis of single-subject data sequences.

Techniques from the field of quality control can be used to classify the quality of individual samples of physical or cognitive performance. After stable baselines have been established for an individual, deviations in performance can be evaluated using control charts. The effectiveness of this approach in evaluating cognitive performance was tested using databases collected under a variety of risk factors. The sensitivity and specificity characteristics of Shewhart, cumulative-sum (CUSUM), and exponentially weighted moving average (EWMA) control charts were determined for a total of 174 trials involving 10 participants and 23 cognitive performance assessment measures. The most effective technique in each case was typically a function of the specific performance measure and the type of performance change being evaluated. Sensitivity and specificity for the best techniques were as high as 100%. This study demonstrated the usefulness of quality control charts as a tool to evaluate individual participant performance over time. Actual or potential applications of this research include readiness-to-perform screening of industrial workers in order to improve the health and safety of the workforce.

Data Interpretation, Statistical↗

Automated screening for quality control using PAPNET: a study of 638 negative Pap smears.

To determine if the PAPNET screening system can be used for quality control to lower false-negative rates for Pap smears 638 manually screened, "negative" Pap smears were subjected retrospectively to the PAPNET screening system. Twenty-nine of the smears came from 18 patients who subsequently had biopsyproven high-grade squamous intraepithelial lesions (SIL). The remaining 609 negative smears were arbitrarily selected as controls. One hundred twenty-eight (128) of the retrospectively reviewed smears (20%) were selected by PAPNET for microscopic referral because of potential abnormalities. Abnormalities were confirmed on 14 of these smears upon microscopic evaluation. Five of these 14 smears were from smears obtained from four of the 18 women with high-grade SIL. The incidence of manually screened false-negatives detected by PAPNET rescreening was 14/638 or 2.2% for the entire patient population in this study and 5/29 or 17.24% for the targeted patients known to have subsequently developed highgrade lesions. The 2.2% decrease in the false-negative rate in this experiment may be partly artificial as this study group was seeded with false-negative cases at high risk for containing missed abnormalities. The implementation of the PAPNET system for quality control may lower false-negative rates for Pap smears.

Automation↗

Reliability of current techniques for histamine determination in human plasma: the European external quality control study 1988.

The increasing importance of measuring histamine in many clinical conditions and the variety of currently used techniques enforced us to organize an external quality control study (ring study) on the reliability of histamine measurements in European laboratories. Three plasma quality control samples in duplicate (lyophilized) with different amounts of histamine (0-5 ng/ml), two different aqueous histamine standard samples and one solvent sample were sent to 10 laboratories for analysis of their histamine content. The following methods were used: gas chromatographic-mass-spectrometric technique (n = 2), single isotope assay (n = 1), fluorometric-fluoroenzymatic assay (n = 3), radioimmunoassay (n = 3), HPLC technique (n = 2). The study was performed and evaluated according to the approved recommendation (1983) of the International Federation of Clinical Chemistry (IFCC). This first report of the study is concentrated on the imprecision and inaccuracy of the different principal methods and laboratories by comparing two unrelated plasma histamine samples of different analyte concentrations (target values and SD: 4.39 +/- 0.51 ng/ml and 0.99 +/- 0.17 ng/ml). This study showed a fairly good agreement between most participants. 7/11 results obtained with 4 different methods were accurate and precise in the plasma range of histamine (Youden plot). Results outside the borderlines turned out to be a problem of the analyst rather than the method itself. It is suggested to define reference values for plasma histamine and to establish reference laboratories and methods according to the IFCC-guidelines.

Adult↗

Intrinsic uniformity and relative sensitivity quality control tests for single-head gamma cameras.

OBJECTIVE: We sought to determine the best parameters for rapid performance of daily quality control testing of intrinsic uniformity and relative sensitivity for the single-head gamma-camera system in our nuclear medicine department. METHODS: The effects of the following parameters on intrinsic uniformity were studied: gamma source activity, number of acquired counts for the flood image, source-to-camera distance, image matrix size, and source volume. The dead time of the system was determined experimentally using the two-source method for accurate calculation of relative sensitivity. RESULTS: A set of parameters for rapid performance of daily gamma-camera intrinsic uniformity and relative sensitivity was determined. The dead time of our gamma-camera system was found to be 4.5 +/- 0.2 micros. CONCLUSION: With our recommended parameters, the intrinsic uniformity and relative sensitivity quality control testing can be performed in 5-6 min. The dead time of each gamma-camera system must be determined experimentally in each nuclear medicine department.

Gamma Cameras↗

Comparing the power of quality-control rules to detect persistent increases in random error.

This paper continues an investigation into the merits of an alternative approach to the statistical evaluation of quality-control rules. In this report, computer simulation is used to evaluate and compare quality-control rules designed to detect increases in within-run or between-run imprecision. When out-of-control conditions are evaluated in terms of their impact on total analytical imprecision, the error detection ability of a rule depends on the relative magnitudes of the between-run and within-run error components under stable operating conditions. A recently proposed rule based on the F-test, designed to detect increases in between-run imprecision, is shown to have relatively poor performance characteristics. Additionally, several issues are examined that have been difficult to address with the traditional evaluation approach.

Chemistry, Clinical↗

Selection, training, and quality control of Type A interviewers in a prospective study of young adults.

This paper describes Type A/B interviewer selection, training, and quality control results in a prospective study of coronary artery risk development in young adults (CARDIA). Interviewer behaviors from 152 CARDIA structured interviews were audited and compared with 747 Western Collaborative Group Study (WCGS) interviews and 577 Multiple Risk Factor Intervention Trial (MRFIT) interviews. The results show success in modeling the CARDIA interviewer behaviors on those of the WCGS. CARDIA interviews were very similar to WCGS interviews for interview length, number of questions asked, and speed of speaking; they were similar to MRFIT interviews in latency of asking questions. CARDIA interviewer behaviors remained fairly consistent over the four time periods. Comparing the clinics, there were regional differences in latency of asking and speed of speaking, with the Southern clinic having a longer asking latency and speaking more slowly. There were differences between individual interviewers in most characteristics, particularly those that were more free to vary. The study provides procedures and guidelines designed to maintain quality control of the structured interview process.

Adolescent↗

Spatially ordered zygotic genome activation fulfills embryo quality control.

Early embryo development features autonomous, maternally driven cell divisions that self-organize the multicellular blastula or blastocyst tissue. Maternal control cedes to the zygote starting with the onset of widespread zygotic genome activation (ZGA), which is essential for subsequent cell fate determination and morphogenesis. Intriguingly, although ZGA onset is highly regulated at the level of the whole embryo, it can be non-homogenous and precisely patterned at the single-cell level. We previously demonstrated a stereotyped spatial and temporal ordering of ZGA in a model vertebrate embryo. Unknown, however, was whether this precise ZGA patterning was required for development. To address this fundamental question, we devised a strategy to spatially control cell divisions that perturb blastula embryo organization. We demonstrate the feasibility of spatially inverting the cell size pattern of embryos and find that these inverted embryos exhibit a flipped pattern of ZGA. Mispatterned ZGA along the animal-vegetal axis triggers embryo apoptosis, revealing that gastrula embryos have a built-in quality control system to sense inappropriate ZGA patterning, including regionalized defects in transcriptional onset. The quality control response is nonautonomous, dependent on an anti-apoptotic signal that suppresses cell death outside the animal hemisphere. These results reveal the requirement of properly patterned ZGA for normal development and the existence of a surveillance system of embryo quality control exquisitely tuned to the spatial and temporal ordering of genome activation and zygotic gene expression.

Animals↗

[Proposal for a quality control procedure for rotating gamma camera tomographic systems].

Single photon emission computerized tomography using a rotating gamma camera needs accurate calibration of electromechanical components, detection system and reconstruction software. A complete group of quality control procedures, developed on the basis of experience and experimental data acquired using a series of widely used gamma camera SPECT systems is presented. The procedures are divided into controls related to the rotational movement. of the detector and controls on the principal physical parameters characterizing a tomographic image. All quality controls here presented were performed with commercial phantoms.

Quality Control↗

In vitro evaluation of Augmentin by broth microdilution and disk diffusion susceptibility testing: regression analysis, tentative interpretive criteria, and quality control limits.

Augmentin (Beecham Laboratories, Bristol, Tenn.), a combination drug consisting of two parts amoxicillin to one part clavulanic acid and a potent beta-lactamase inhibitor, was evaluated in vitro in comparison with ampicillin or amoxicillin or both for its inhibitory and bactericidal activities against selected clinical isolates. Regression analysis was performed and tentative disk diffusion susceptibility breakpoints were determined. A multicenter performance study of the disk diffusion test was conducted with three quality control organisms to determine tentative quality control limits. All methicillin-susceptible staphylococci and Haemophilus influenzae isolates were susceptible to Augmentin, although the minimal inhibitory concentrations for beta-lactamase-producing strains of both groups were, on the average, fourfold higher than those for enzyme-negative strains. Among the Enterobacteriaceae, Augmentin exhibited significantly greater activity than did ampicillin against Klebsiella pneumoniae, Citrobacter diversus, Proteus vulgaris, and about one-third of the Escherichia coli strains tested. Bactericidal activity usually occurred at the minimal inhibitory concentration. There was a slight inoculum concentration effect on the Augmentin minimal inhibitory concentrations. On the basis of regression and error rate-bounded analyses, the suggested interpretive disk diffusion susceptibility breakpoints for Augmentin are: susceptible, greater than or equal to 18 mm; resistant, less than or equal to 13 mm (gram-negative bacilli); and susceptible, greater than or equal to 20 mm (staphylococci and H. influenzae). The use of a beta-lactamase-producing organism, such as E. coli Beecham 1532, is recommended for quality assurance of Augmentin susceptibility testing.

Amoxicillin↗