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At least 1,135 records · Page 63Linked to original sources
PubMed2004

MIC quality control guidelines for doxycycline when testing gram-positive control strains by the reference methods.

With emerging resistance to fluoroquinolones, there arises a need to establish quality control (QC) guidelines for doxycycline, an effective alternative for treating various community-acquired respiratory tract infections. This multicenter study was performed to establish QC guidelines for susceptibility testing those Gram-positive QC organisms against doxycycline. The proposed three or four log2 dilution MIC ranges included 100.0% of the doxycycline MIC values reported.

Anti-Bacterial Agents↗
PubMed2004

Development of a standardized susceptibility test for campylobacter with quality-control ranges for ciprofloxacin, doxycycline, erythromycin, gentamicin, and meropenem.

A standardized agar dilution susceptibility testing method was developed for Campylobacter that consisted of testing on Mueller-Hinton medium supplemented with 5% defibrinated sheep blood in an atmosphere of 10% CO2, 5% O2, and 85% N2. Campylobacter jejuni ATCC 33560 was identified as a quality-control (QC) strain. Minimal inhibitory concentration (MIC) QC ranges were determined for two incubation time/temperature combinations: 36 degrees C for 48 hr and 42 degrees C for 24 hr. Quality-control ranges were determined for ciprofloxacin, doxycycline, erythromycin, gentamicin, and meropenem. For all antimicrobial agents tested at both temperatures, 95-100% of the QC MIC results fell within recommended QC ranges. Twenty-one Campylobacter clinical isolates, encompassing five species of Campylobacter (C. jejuni, C. coli, C. jejuni, subsp. doylei, C. fetus, and C. lari) were tested in conjunction with the C. jejuni QC strain. While C. jejuni and C. coli could be reliably tested under both test conditions, growth of C. jejuni subsp. doylei, C. fetus, and C. lari isolates was inconsistent when incubated at 42 degrees C. Therefore, it is recommended that these species only be tested at 36 degrees C.

Campylobacter↗
PubMed2006

Cimicifuga species identification by high performance liquid chromatography-photodiode array/mass spectrometric/evaporative light scattering detection for quality control of black cohosh products.

Black cohosh has become one of the most important herbal products in the US dietary supplements market. It is manufactured from roots and rhizomes of Cimicifuga racemosa (Ranunculaceae). Botanical identification of the raw starting material is a key step in the quality control of black cohosh preparations. The present report summarizes a fingerprinting approach based on high performance liquid chromatography-photodiode array/mass spectrometric/evaporative light scattering detection (HPLC-PDA/MS/ELSD) that has been developed and validated using a total of 10 Cimicifuga species. These include three North American species, Cimicifuga racemosa, Cimicifuga americana, Cimicifuga rubifolia, and seven Asian species, Cimicifuga acerina, Cimicifuga biternat, Cimicifuga dahurica, Cimicifuga heracleifolia, Cimicifuga japonica, Cimicifuga foetida, and Cimicifuga simplex. The chemotaxonomic distinctiveness of the HPLC fingerprints allows identification of all 10 Cimicifuga species. The triterpene glycoside cimigenol-3-O-arabinoside (3), cimifugin (12), and cimifugin-3-O-glucoside (18) were determined to be suitable species-specific markers for the distinction of C. racemosa from the other Cimicifuga species. In addition to identification, the fingerprint method provided insight into chemical interconversion processes occurring between the diverse triterpene glycosides contained in black cohosh. The reported method has proven its usefulness in the botanical standardization and quality control of black cohosh products.

Chromatography, High Pressure Liquid↗
PubMed1986

Quality control aspects of pulmonary function testing in the Multiple Risk Factor Intervention Trial.

Pulmonary function testing was used in MRFIT to monitor the presence of airways disease and to assess changes in pulmonary function over time. The pulmonary function indices that were measured were FEV1, FVC, and MMEF, (FEF25-75). Quality control of technician training, equipment maintenance, data collection, and data measurement were essential to ensure that results, over time and from various clinics, could be compared. Based on the MRFIT experience, it is strongly recommended that centralized training in testing techniques and spirometer maintenance take place before a clinical trial begins, and periodically throughout a trial. Such training, combined with quality control follow-up, should prevent the loss of data due to inadequate spirometer maintenance and invalid testing procedures.

Allied Health Personnel↗
PubMed1992

[Quality assurance or quality control. Lessons from an intercomparison circuit].

This article deals with the evaluation of the three year results of the French interlaboratory control for serum copper and zinc analysis. We pointed out some results interpreted on the basis of the existence of differences between the notions of quality control and total quality assurance. The main finding was a surprising change in the annual range in the final results of the laboratories. All 'good' laboratories in the first year showed a significant fall in their individual performance the second year. We can interpret that as a falling off of vigilance in relation with the self satisfaction after the publication of the first results. We concluded that good laboratory practices must be accompanied by a quality program not limited to an analytical control.

Copper↗
PubMed2003

A striking quality control subcompartment in Saccharomyces cerevisiae: the endoplasmic reticulum-associated compartment.

The folding of nascent secretory and membrane proteins is monitored by the endoplasmic reticulum (ER) quality control system. Misfolded proteins are retained in the ER and can be removed by ER-associated degradation. As a model for the ER quality control of multispanning membrane proteins in yeast, we have been studying mutant forms of Ste6p. Here, we identify mislocalized mutant forms of Ste6p that induce the formation of, and localize to, prominent structures that are absent in normal cells. We have named these structures ER-associated compartments (ERACs), based on their juxtaposition to and connection with the ER, as observed by fluorescence and electron microscopy. ERACs comprise a network of tubulo-vesicular structures that seem to represent proliferated ER membranes. Resident ER lumenal and membrane proteins are present in ERACs in addition to their normal ER localization, suggesting there is no barrier for their entry into ERACs. However, the forms of Ste6p in ERACs are excluded from the ER and do not enter the secretory pathway; instead, they are ultimately targeted for ER-associated degradation. The presence of ERACs does not adversely affect secretory protein traffic through the ER and does not lead to induction of the unfolded protein response. We propose that ERACs may be holding sites to which misfolded membrane proteins are specifically diverted so as not to interfere with normal cellular functions. We discuss the likelihood that related ER membrane proliferations that form in response to certain other mutant or unassembled membrane proteins may be substantially similar to ERACs.

ATP-Binding Cassette Transporters↗
PubMed1982

Chemical quality control of [99mTc]plasmin by affinityradiochromatography.

To establish a method for radiochemical quality control of [99mTc]plasmin based on the known affinity of plasmin for lysine residues, human [113Sn]plasmin and [99mTc]plasmin formed by different methods were analyzed in an affinityradiochromatographic system of lysine coupled to CNBr-activated sepharosis. From the observed immobilizations of the radioactivity when the plasmin was bound to the lysine-sepharosis, radiochemical purities of radiolabelled plasmin could be calculated. The effects of presence of Sn(II) and tartaric and gentisic acid and the remobilizations induced by 6-aminohexanoic acid were studied.

Chromatography, Affinity↗
PubMed2006

[Study on quality control of Paeonia lactiflora].

OBJECTIVE: To provide the experimental data for the quality control of Paeonia lactiflora a prepared Chinese medicinal herb. METHOD: The contents paeoniflorin among different growing areas and different processing methods methods were assayed by HPLC. RESULT: The quantitative differences of paeoniflorin content among different growing areas and different processing methods wereanalyzed quantitatively. CONCLUSION: The quantitative differences among different growing areas were not significant and the quantitative differences among different processing methods within 10%.

Benzoates↗
PubMedDate not supplied

Quality control in the food industries with DNA technologies.

An important part of quality control in the food industry are tests to determine the origin of materials used in processed products. Because of the stability of DNA, tests which make use of DNA in the product can be used to authenticate the species used in meat pies, tinned fish and even the variety of oats used in porridge. Tests based on hybridization, sequencing of oligonucleotides and amplification of DNA are likely to find increasing application with the only inhibition being the unpredictable nature of the market which makes commercial development difficult.

Animals↗
PubMed2002

Towards in vivo monitoring of neutron distributions for quality control of BNCT.

Dose delivery in boron neutron capture therapy (BNCT) is complex because several components contribute to the dose absorbed in tissue. This dose is largely determined by local boron concentration, thermal neutron distribution and patient positioning. In vivo measurements of these factors would considerably improve quality control and safety. During therapy, a y-ray telescope measures the y-rays emitted following neutron capture by hydrogen and boron in a small volume of the head of a patient. Scans of hydrogen y-ray emissions could be used to verify the actual distribution of thermal neutrons during neutron irradiation. The method was first tested on different phantoms. These measurements showed good agreement with calculations based on thermal neutron distributions derived from a treatment planning program and from Monte Carlo N-particle (MCNP) simulations. Next, the feasibility of telescope scans during patient irradiation therapy was demonstrated. Measurements were reproducible between irradiation fractions. In theory, this method can be used to verify the positioning of the patient in vivo and the delivery of thermal neutrons in tissue. However, differences between measurements and calculations based on a routine treatment planning program were observed. These differences could be used to refine the treatment planning. Further developments will be necessary for this method to become a standard quality control system.

Algorithms↗
PubMed1997

Susceptibility testing quality control studies with fosfomycin tromethamine.

Multiple studies were performed to define the quality control ranges for susceptibility tests of fosfomycin tromethamine. For disk diffusion tests, the limits proposed are 22 to 30 mm for Escherichia coli ATCC 25922 and 25 to 33 mm for Staphylococcus aureus ATCC 25923. Broth microdilution tests were not reproducible. For agar dilution tests, ranges proposed are 0.5 to 2.0 micrograms/ml for Escherichia coli ATCC 25922, 0.5 to 4.0 micrograms/ml for Staphylococcus aureus ATCC 29213; 2.0 to 8.0 micrograms/ml for Pseudomonas aeruginosa ATCC 27853, and 32 to 128 micrograms/ml for Enterococcus faecalis ATCC 29212.

Anti-Bacterial Agents↗
PubMedDate not supplied

ECVAM's contributions to the implementation of the Three Rs in the production and quality control of biologicals.

A summary is presented of the activities initiated, and the progress achieved, between April 1993 and December 2001 in implementing the Three Rs in one of the main priority areas of the European Centre for the Validation of Alternative Methods (ECVAM) - the production and quality control of biologicals. These have included organising eight key workshops, and financial contributions to, and sponsorship of, relevant international workshops, symposia and conferences. Noteworthy activities include financial support and/or participation in a number of prevalidation and validation studies. These involved alternative methods for the batch potency testing of: human tetanus vaccines; human and veterinary tetanus antisera and immunoglobulin; rabies vaccines; Leptospira hardjo vaccines; Clostridium perfringens vaccines; and erysipelas vaccines. They also involved a cell culture test for specific toxicity testing of diphtheria toxoid vaccines. In addition, ECVAM funded a study on the use of humane endpoints for vaccine quality control tests involving severe suffering, such as the potency testing of erysipelas, rabies and pertussis vaccines. ECVAM has also contributed financially to the compilation of manuals and expert reports, and to training in test methods. Following the report of an ECVAM Task Force, ECVAM financially supported the prevalidation of some in vitro methods for the potency testing of a recombinant hormone. A proposal is presented for promotion of regulatory acceptance, and suggestions are made for possible future activities.

Animal Testing Alternatives↗
PubMed1996

Quality control of HIV cultures in a clinical retrovirology laboratory.

The culture of primary HIV isolates requires fresh phytohemagglutinin (PHA) stimulated peripheral blood mononuclear cells (PBMC) from seronegative donors. The variation inherent in donor cells, obtained from many different individuals, might affect the likelihood of virus isolation. We developed a quality control (QC) procedure which could determine quantitatively the susceptibility of random donor cells to HIV infection. The QC reagents consisted of cells and supernatants infected with a syncytium-inducing clinical isolate of HIV. Six 5-fold dilutions of QC cells (starting at 1000 cells) and supernatant (starting at a 1:200 dilution) were cultured in parallel with 1 x 10(6) 2-3-day-old PHA stimulated donor cells. After 7 or 14 days the resulting culture supernatant was tested for syncytia formation with MT-2 cells. A total of 127 sequential donors were tested over an 11 month period. All but one donor PBMC preparation was capable of being infected by the QC reagents (and this particular donor was permissive for several other primary isolates). The standard variation observed among all cultures was about one 5-fold dilution. The coefficient of variation ranged from 10.7 to 17.3%. These results suggest that the mononuclear cells from most, if not all, individuals are permissive for HIV to approximately the same level. Other quality control measures used in the laboratory are described.

Cell Line↗
PubMed1991

The need for immediate monitoring of treatment parameters and uniform assessment of patient data in clinical trials. A quality control study of the EORTC Radiotherapy and Lung Cancer Cooperative Groups.

A quality control study was performed during the EORTC phase III study 08844: radiotherapy combined with low dose cisplatin (cDDP) in inoperable non-metastatic non-small cell lung cancer. Radiation alone (55 Gy, split course) was compared to radiotherapy with 30 mg/m2 cisplatin once a week and to radiotherapy with 6 mg/m2 cisplatin daily. The purpose of the control study was to check to which degree protocol guidelines were followed and to measure the extent of differences in assessment of tumour response, recurrence and toxicities between the individual institutes. A review team, consisting of a data manager, a diagnostic radiologist, a chest physician and two radiotherapists reviewed entry criteria, treatment data, tumour responses, recurrences and late toxicity of 177 patients (a total of 300 patients was required for the trial). Only departments which had entered more than 5% of this number of patients were visited. There was a 15% difference in T staging of the patients and a 17% discrepancy in N stage scoring between the review team and the local investigators. Radiotherapy field sizes were insufficient in 15% of the eligible patients during a period of the radiotherapy; in another 17% patients the tumour free margin was less than 1 cm. Radiation doses were incorrectly given to 7% of the patients. The given doses of cisplatin deviated in 10% of the patients treated with combined modalities. The interpretation of chest X-rays and computed tomography (CT) showed important differences in tumour response, tumour recurrence and late toxicity. From these data it is concluded that immediate checks can detect errors in treatments as planned at the local level and will make corrections possible at an early stage in multicentre studies. The quality of trial results will thus be improved. Uniform assessment of treatment outcome, tumour progression and forms of toxicity will lead to more sound trial conclusions.

Carcinoma, Bronchogenic↗
PubMed1995

Cytologic/histologic correlation for quality control in cervicovaginal cytology. Experience with 1,582 paired cases.

For quality-control purposes, federal regulations require cytology laboratories to compare Papanicolaou smear and cervical biopsy reports, if available, and determine the cause of any discrepancies. The authors reviewed 56,497 cervicovaginal smears, of which 1,582 (2.8%) had a subsequent cervical biopsy or endocervical curettage within 2 months. A total of 175 discrepancies (11%) were identifed, and biopsies and smears from these cases were reviewed at a weekly conference. In the majority of cases, the diagnosis of the smear and biopsy was confirmed on review, and the discrepancy was attributed to sampling error (n = 159; 91%). Six cases (3.4% of all discrepant cases) were errors in cytologic diagnosis. Five of these were interpretation errors, and one case was a screening error. There were 10 errors in the evaluation of cervical biopsies (5.7% of all discrepant cases): five biopsies were undercalled, and five were overdiagnosed as a squamous intraepithelial lesion. The results of testing for human papillomavirus DNA by in situ hybridization were helpful in arbitrating some diagnositic disagreements.

Biopsy↗
PubMed1978

[External quality control for anti-D demonstration within the scope of Rh immunoprevention].

In the GDR the success and the dosage of IgG-anti-D in immune prophylaxis after birth of Rh-positive infants from Rh-negative mothers are controlled by the estimation of anti-D antibodies in maternal serum. For this purpose the papain method was introduced in centers for immune prophylaxis since 1970/71 at the time of general introduction of this immune prophylaxis in the GDR. The results if five external quality control experiments in the 16 to 18 such centers in the district of Magdeburg between 1972 and 1977 are recorded. The false positive and false negative reports are discussed and the demand for those regular external quality controls is carried ant.

Antibody Specificity↗
PubMed1986

Use of a quality-control plasma sample to decrease interassay variation in radioimmunoassays of apolipoprotein A-I.

The apolipoprotein A-I (apo A-I) radioimmunoassay established in our laboratory involves use of purified apo A-I as the primary standard for quantifying apo A-I in plasma and a pooled plasma (quality-control sample) as a secondary standard to decrease interassay variation. The measured values for apo A-I increased over time as the labeled antigen degraded. We observed these results in two separate studies: (a) apo A-I in plasma from 16 subjects was measured 12 times during four months, and (b) apo A-I in a single pooled plasma was measured 48 times during 10 months. We show that use of a quality-control plasma sample as a secondary standard decreased interassay variation, which was, in part, ascribable to degradation of the labeled antigen.

Adult↗