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At least 973 records · Page 54Linked to original sources
PubMed2006

Quality control of banked milk in Brasilia, Brazil.

The authors studied quality control procedures at human milk banks and nutritional profiles of 909 milk samples (from 195 donors, aged 15 to 45 years) from banked human milk (BHM) in Brasília, Brazil. Number of donations per donor ranged from 1 to > 10 that consisted mostly of mature milk (90.9%) with a mean total energy of 529 +/- 85 kcal/L and a mean total lipid of 22.7 g/L +/- 13.2. Microbiological quality (titrable acidity-Dornic, degrees D) was suitable for infant feeding in 99.2% of samples (< 8 degrees D), ranging from 2 degrees D to 8 degrees D (mean 4.8 +/- 1.4 degrees D). Most BHM (98.1%) samples were dispensed to inpatient infants (1-7 days) diagnosed with respiratory distress (30.1%), prematurity (20.7%), metabolic distress (16.0%), jaundice (14.4%), bacterial infection (6.0%), pneumonia (3.3%), congenital cardiac distress (2.2%), or other conditions (6.2%). Well-motivated mothers and trained staff are serving and sustaining an important life-saving network with long-lasting impact on public health.

Adolescent↗
PubMed1998

Protein folding stability can determine the efficiency of escape from endoplasmic reticulum quality control.

A fraction of each secreted protein is retained and degraded by the endoplasmic reticulum (ER) quality control apparatus that restricts export to correctly folded proteins. The intrinsic biophysical attributes that determine efficiency of escape from this proofreading process have been examined by expressing mutants of bovine pancreatic trypsin inhibitor (BPTI) in yeast. Secretion efficiency is strongly correlated with thermodynamic stability for a series of six point mutations of BPTI. No correlation of secretion efficiency with either oxidative folding or refolding rates in vitro is found; both the rapidly folded Y35L BPTI mutant and the slowly unfolded G36D BPTI mutant exhibit low secretion efficiency. Elimination of cysteines 14 and 38 by mutagenesis does not increase secretion efficiency, indicating that intramolecular thiol/disulfide rearrangements are not primarily responsible for retention and degradation of destabilized BPTI variants. Mutant yeast strains with diminished ER-associated degradation do not secrete BPTI more efficiently, indicating that retention and degradation are separable processes. These data support a model for ER quality control, wherein protein folding is functionally reversible and the relative rates of folding, unfolding, vesicular export, and retention determine secretion efficiency.

Aprotinin↗
PubMed2000

Golgi apparatus immunolocalization of endomannosidase suggests post-endoplasmic reticulum glucose trimming: implications for quality control.

Trimming of N-linked oligosaccharides by endoplasmic reticulum (ER) glucosidase II is implicated in quality control of protein folding. An alternate glucosidase II-independent deglucosylation pathway exists, in which endo-alpha-mannosidase cleaves internally the glucose-substituted mannose residue of oligosaccharides. By immunogold labeling, we detected most endomannosidase in cis/medial Golgi cisternae (83.8% of immunogold labeling) and less in the intermediate compartment (15.1%), but none in the trans-Golgi apparatus and ER, including its transitional elements. This dual localization became more pronounced under 15 degrees C conditions indicative of two endomannosidase locations. Under experimental conditions when the intermediate compartment marker p58 was retained in peripheral sites, endomannosidase was redistributed to the Golgi apparatus. Double immunogold labeling established a mutually exclusive distribution of endomannosidase and glucosidase II, whereas calreticulin was observed in endomannosidase-reactive sites (17.3% in intermediate compartment, 5.7% in Golgi apparatus) in addition to the ER (77%). Our results demonstrate that glucose trimming of N-linked oligosaccharides is not limited to the ER and that protein deglucosylation by endomannosidase in the Golgi apparatus and intermediate compartment additionally ensures that processing to mature oligosaccharides can continue. Thus, endomannosidase localization suggests that a quality control of N-glycosylation exists in the Golgi apparatus.

Animals↗
PubMed2002

Interobserver agreement and performance score comparison in quality control using a breast phantom: screen-film mammography vs computed radiography.

Our objective was to evaluate interobserver agreement and to compare the performance score in quality control of screen-film mammography and computed radiography (CR) using a breast phantom. Eleven radiologists interpreted a breast phantom image (CIRS model X) by four viewing methods: (a) original screen-film; (b) soft-copy reading of the digitized film image; (c) hard-copy reading of CR using an imaging plate; and (d) soft-copy reading of CR. For the soft-copy reading, a 17-in. CRT monitor (1024x1536x8 bits) was used. The phantom image was evaluated using a scoring system outlined in the instruction manual, and observers judged each object using a three-point rating scale: (a) clearly seen; (b) barely seen; and (c) not seen. For statistical analysis, the kappa statistic was employed. For "mass" depiction, interobserver agreement using CR was significantly lower than when using screen-film ( p<0.05). There was no significant difference in the kappa value for detecting "microcalcification"; however, the performance score of "microcalcification" on CR hard-copy was significantly lower than on the other three viewing methods ( p<0.05). Viewing methods (film or CR, soft-copy or hard-copy) could affect how the phantom image is judged. Paying special attention to viewing conditions is recommended for quality control of CR mammograms.

Female↗
PubMed1982

The infant formula industry, the Infant Formula Act of 1980, and quality control.

Throughout the months following the discovery of the low-chloride problem in infant formula, the industry undertook independent and voluntary measures to ensure the compositional quality of formulas. Members of the Infant Formula Council reviewed industry procedures, practices, and policies, and submitted a detailed description of its quality control and clinical testing procedures to the Food and Drug Administration. New product concepts and product reformulation proposals are based on medical and nutritional findings, on changes in medical concepts for nutritional support, on availability of improved nutrient sources, or on improved ingredients or processing technologies. Quality control is maintained throughout the manufacturing process through inspection of raw materials, analysis of major and minor constituents, equipment and process controls, and continuous product monitoring. However, despite cooperation of the infant formula industry with FDA and Congress during the development of the infant formula bills, the proposed document was too rigid and did not take into account that manufacturing methods of a given manufacturer often vary for the same product, for different products, and on different production equipment. The statistical criteria established uneven and inconsistent requirements for various manufacturers. Congress did not forsee that the proposed regulatory procedures would significantly affect industry.

Humans↗
PubMed2006

Quality control limits for posaconazole disk susceptibility tests on Mueller-Hinton agar with glucose and methylene blue.

A multilaboratory collaborative study was performed in order to propose quality control limits for posaconazole disk diffusion susceptibility tests on Mueller-Hinton agar supplemented with 2% glucose and 0.5 microg of methylene blue per ml. Replicate tests were performed on three lots of prepared media using 5-microg posaconazole disks in each of eight laboratories to generate data to propose quality control zone diameter ranges for tests of Candida albicans ATCC 90028 (24 to 34 mm), C. parapsilosis ATCC 22019 (25 to 36 mm), C. tropicalis ATCC 750 (23 to 33 mm), and C. krusei ATCC 6258 (23 to 31 mm).

Agar↗
PubMedDate not supplied

[Quality control of erythrocyte concentrates in 6 transfusion centers in Croatia].

Quality control of red cell concentrates (RCC) was performed in six Blood Transfusion Centres in Croatia. Between 1.5 and 3.7% of the produced or/and used RCC were examined. Large differences in volume and haematocrit were found between red cell concentrates. 63.2% of concentrates had a volume larger than 225 ml. The mean haematocrit was 65.5%, and a haematocrit above 65% was observed in 51.6% of RCC. From 3.5% of RCC bacteria were isolated (gram positive coccus, Staphylococcus albus, Staphylococcus epidermidis and Streptococcus haemolyticus). The quality of RCC was not found to be satisfactory. In order to improve their quality procedures for their production, standards and legal requirements have to be established.

Blood Transfusion↗
PubMed2002

[Quality control for antimicrobial susceptibility test using correlation between MIC results].

The method of National Committee for Clinical Laboratory Standards (NCCLS) is widely used for the daily quality control of the antimicrobial susceptibility test. This method, however, cannot detect the accidental error, although it is useful to detect the systematic error in the examination. We developed a computer program using the correlation between the various antimicrobial susceptibility test results to detect an accidental error. The combinations of the MIC results determined for two antimicrobial agents which showed a high correlation coefficient (> or = 0.7), were selected from 98 bacterial species (2122 strains) isolated from January 2000 to December 2000 at Oita Medical University Hospital. Subsequently, a total of 127 combinations of antimicrobial agents for 13 species were selected on the basis of acceptable correlation ranges. Then, the method were verified with 666 strains (5753 combinations) isolated during the period of January to June, 2001. Twenty-six strains (47 combinations) were identified as an unexpected result, and the occurrence of error were confirmed in 3 strains (12 combinations). These results suggest that this method which evaluated the correlation between MICs against different antimicrobial agents is applicable for the quality control of antimicrobial susceptibility testings.

Anti-Bacterial Agents↗
PubMed2000

Using videotaped specimens to test quality control in a computer-assisted semen analysis system.

OBJECTIVE: To determine the feasibility of using semen samples previously recorded on videotape for intralaboratory and interlaboratory quality control of computer-assisted semen analysis (CASA) systems. DESIGN: Blinded, controlled study. SETTING: Pooled semen specimens from two normal human volunteers in an academic research environment. PATIENT(S): None. INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Semen parameters from a videotape analyzed internally and by four external laboratories. RESULT(S): Preliminary experiments designed to examine intralaboratory variation by repeated analysis of semen samples recorded on videotape revealed some significant differences for every variable examined. When these data were analyzed by using the larger biologic error caused by subsampling, no significant differences were found for any of the variables examined. When either a standard set or the specific laboratories' sets of parameters were used to analyze the same videotaped semen specimen, no statistically significant differences were detected for sperm concentration for motility among the five laboratories after the biological error caused by subsampling was applied to results. CONCLUSION(S): These data strongly suggest that videotaped semen specimens can serve as quality control for intralaboratory and interlaboratory testing of CASA equipment as long as the biologic error caused by subsampling is used to compare results.

Cytological Techniques↗
PubMed1993

Performance assessment and quality control in MRI by Eurospin test objects and protocols.

As part of its work, the European Concerted Action "Tissue Characterisation by MRS and MRI" (COMAC-BME) has expended considerable effort in the field of magnetic resonance imaging (MRI) quality control. A set of test objects--the Eurospin set--have been designed and rigorously tested in many systems throughout Europe. The full history of this development is described, together with a detailed presentation of the types of measurements that are achievable with such test objects and examples of the results. Further, the principles of more complex Stage II tests (which involve invasive interaction with the system) are introduced. Finally, simplified methods of quantifying the overall performance are discussed and the levels of MRI quality control from acceptance testing to routine quality assurance outlined.

Animals↗
PubMed2005

Anaesthesia record system on handheld computers--pilot experience and uses for quality control and clinical guidelines.

This paper describes a mobile information system to collect patient information for anesthesia quality control. In this system, a mobile database program was designed for use on handheld computers (Pocket PC). This program is used to collect patient data at the bedside on the handhelds, with a daily synchronization of the data between the anaesthesiologists' handhelds with the anaesthesia database. All collected data are later used for quality control analysis. Furthermore, clinical guidelines will be included on these same handhelds. During the pilot phase, data from a sample set of about 300 patients were incorporated. The processes and interfaces of the system are presented in the paper. The current mobile database system has been designed to replace the original paper-based data collection system. The individual anaesthesiologist's handheld synchronizes patient data daily with anaesthesia database center. This information database is analyzed and used not only to give feedback to the individual doctor or center, but also to review the use of the guidelines provided and the results of their utilization.

Anesthesia↗
PubMed1989

Pseudomonas aeruginosa ATCC 49189, a new quality control strain for testing P. aeruginosa susceptibility to the aminoglycosides.

Quality control for in vitro antimicrobial susceptibility testing of Pseudomonas aeruginosa versus aminoglycosides is improved by P. aeruginosa ATCC 49189, which was developed in the Clinical Microbiology Laboratory at St. Paul-Ramsey Medical Center. This strain, used by us for daily testing for the past 6 years, requires MICs that approximate therapeutic concentrations, are midrange in most dilution schemes, and are stable and reproducible.

Aminoglycosides↗
PubMed1991

Quality assurance and quality control in toxicology: how might these concepts apply to epidemiology?

Quality assurance and its distinction from quality control are defined in operational terms. The historical development of standards for scientific research supporting commercialization of materials leading to the current Good Laboratory Practice (GLP) standards is briefly outlined. The application of GLPs to toxicology studies and experience in the use of these standards over a broad range of activities is also presented. This background information provides a common starting point for consideration of the development and application of similar standards for epidemiological studies.

Epidemiologic Methods↗
PubMed1998

[Quality control of homologous blood collection activities: 5 years' experience].

Quality control (QC) of blood collection activities for transfusion is a regulatory requirement. The authors report on their experience in this field over the past 5 years. In their institution, this QC is based on both the recording and analyzing of predefined data, as well as the search for an active collaboration from each person involved in these activities. QC of medical selection relies on the assessment of several associated criteria: effectiveness of the information given to blood donors for recruitment, preparation of the medical interview and encouragement to perform regular donations; frequency of donors deferred after the medical interview; frequency of biological abnormalities detected at donation; results of the inquiries into the corresponding medical interviews following adverse transfusion reactions. The quantitative and qualitative evaluation of blood collection permits assessment of the quality of the blood collection program, collection procedures and directly derived blood products. Quality assessment of facilities and equipment is also included in this QC. Results have been improving in recent years, especially regarding medical selection. In particular, an increase in the mean donation rate of donors, a decrease in biological abnormalities detected at donation and an absence of adverse transfusion reactions attributed after inquiry to an inadequate medical interview have been noticed. A decrease in both shortage and outdating of labile blood products likewise indicates an improvement of blood collection planning. However, this QC reveals deficiencies in the information given to donors and a lack of analysis of the data specific to first time donors. In order to further improve the efficiency of QC, these results now require comparison with similar data collected on a nation-wide scale.

Anemia↗
PubMed2001

Quality control of the physical and technical aspects of mammography in the Norwegian breast-screening programme.

The aim of this study was to establish a system for quality control of technical and physical aspects of mammography in the national Norwegian breast-screening programme, and to evaluate test results obtained during the 4-year pilot project period. Quality control (QC) procedures for the X-ray unit, film and processing, cassettes and screens, view boxes, and image quality were described in two QC manuals. Frequent and relatively simple tests were performed by radiographers on-site and results reported semi-annually to an inspection group established at the Norwegian Radiation Protection Authority (NRPA). Tests requiring special equipment were performed prior to start of screening (first status controls), then annually by the NRPA group, which also assembled and analysed the data from the first 4 years. The analyses were done mainly with reference to stated standard or guidance levels and the degree of deviation from such values. Results for tests of i.a. focal spot size, exposure time, radiation output, mean absorbed glandular dose, reference optical density, sensitometry, and AEC performance are presented. The standard of the equipment tested was in general high. Although some deviations from optimal performance were seen throughout the project, the equipment mostly performed well within the stated limiting values.

Aged↗
PubMed1976

[Detection of reagent errors by internal quality control of the Coulter counter S].

By a simple program of quality control for the Coulter counter model S two deficient reagents could be detected. To high values of PCV associated with a decrease of MCHC were caused by a faulty Isoton batch. This error was revealed by native blood samples but not by the stabilized 4 C standard. Falsely elevated leukocyte counts due to insufficiently lysed giant platelets and platelet aggregates were produced by modified Lyse-S batches. Comparisons made with a Coulter counter model F using Zaponin and with a counting chamber yielded values at lower levels.

Blood Cell Count↗
PubMed2001

[Quality control in parasitology].

Between 1990 and 1996 we coordinated a Quality Control (QC) Program in Parasitology directed to Public Health Institutions in Spain. Periodically, parasited specimens, mainly feces or blood, were sent to Microbiology Laboratories for identification. Each QC was accompanied by a short clinic and epidemiological information in order to help in the diagnostic approach. After the answers to the QC were received a bulletin that included the solution to the QC, comments on the several answers received and a chapter with parasitological themes related with the QC, was sent to each participating Laboratory. The bulletin was accompanied by a card that included a photograph and a short description of the organism object of the QC.

Parasitology↗
PubMed1996

Quality control study by the French Cytometry Association on flow cytometric DNA content and S-phase fraction (S%). The Association Française de Cytométrie.

Clinical use of flow cytometric (FCM) DNA analysis requires effective quality controls. Thirty-two laboratories with various degrees of FCM experience participated in the first phase of a quality control program organized by the Association Française de Cytométrie. All received diskettes containing ten list-mode files and ten histogram files that were derived from FCM analysis of various unfixed tumor specimens. A total of 610 responses on DNA ploidy and cell cycle were obtained with three different DNA analysis softwares: CellFit used by (44% of responses), MultiCycle (44%), and ModFit (12%). After statistical analysis, 31% of the responses were excluded from the final analysis for precise reasons. The groups were too small to carry out a valid analysis of the slight differences in the percentage of cells in the DNA synthesis phase (S%) between CellFit and MultiCycle. To estimate the influence of gating on the final cell-cycle results, five of the histogram files were derived from corresponding list-mode files, but the participating laboratories were unaware of this. A good correlation (r = 0.98) was obtained for S% values in the five paired files. The fact that 31% of the responses had to be excluded clearly reflects inadequate training in the use of these analysis softwares and, in some cases, a failure to grasp the biological meaning of the results. In contrast, the laboratories fulfilling consensus recommendations obtained remarkably homogeneous results, showing that standardization is feasible.

Breast Neoplasms↗