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At least 1,621 records · Page 90Linked to original sources
PubMed1994

[Organization and significance of quality control in recent surgical methods exemplified by 85 consecutive thoracoscopic interventions].

The rapid evolution or rather revolution of minimally invasive surgical techniques is stimulating new technical and clinical innovations. Quality control is of great importance in new areas of technical development where standards do not yet exist. By recording detailed documentation of patient data, indications, operative procedures and initial follow-up we can compare this new technology with the gold standard therapy. This documentation system for thoracoscopic interventions was developed together with the Swiss Group of Laparoscopic and Thoracoscopic Surgeons. This pilot project of 85 consecutive thoracoscopic interventions will demonstrate the acceptability, clinical application and ease with which data can be analyzed. Operative techniques are described in detail: 20 diagnostic interventions with biopsy, 19 apical parietal pleurectomies (+/- resections of bullous lung tissue), 10 therapeutic lung tissue resections, 19 palliative pleurodesis, 5 treatments of pleural empyema, 1 mediastinal tumor resection, 1 esophagectomy, 4 thoracic sympathectomies plus 6 other procedures. Data entry is efficient with mean total time of 10 min for each record. All of the data are entered into a computer database. The possibilities for interpreting and combining this data are presented. The operative techniques can easily be related with history, indications, anesthesia, complications and results. First evaluation of thoracoscopic efficiency is possible. In addition, a detailed analysis of intra- and postoperative complications and of the hospital course can be performed.

Documentation↗
PubMed1998

Quality control of culture media--perspectives and problems.

The Working Party on Culture Media (WPCM) of the International Union of Microbiological Societies (IUMS) has promoted and facilitated the development of methods for quality control of culture media used for the detection and enumeration of food-borne microorganisms since the early 1980s. While progress has been made in establishing protocols to test for productivity and selectivity of media, problems associated with the influence of food constituents and background microflora, as well as the presence of sublethally injured cells in test foods, are yet to be fully addressed before optimum methods for assessing the quality of media can be defined. However, for various reasons, the development of standardised procedures which account for the influence of food constituents or state of debilitation of target microorganisms may not be practical or even desirable.

Culture Media↗
PubMed1999

Quality control of polysomnographic sleep data by histogram and entropy analysis.

OBJECTIVE AND METHODS: Sixteen polysomnographic recordings from 8 European sleep laboratories were analyzed. The histogram analysis was used to introduce quality control of all-night EEG recordings. RESULTS: It was found that the header information does not always provide the real saturation values of the recording equipment. The entropy measure was used for the quantitative analysis of the dynamic range of routinely used polysomnographic recorders. It was found that the recording equipment provides EEG data with entropy in the range of 8-11 bits. CONCLUSION: In the all-night sleep EEG were observed non-linearities. It is recommended that the equipment provide the saturation values in order to apply automated overflow detection.

Humans↗
PubMed1978

[Biocompatibility and quality control of pacemaker (author's transl)].

The Authors examine the functional, toxicological and pharmacological controls routinely performed on materials and on the finished products. They propose a biocompatibility protocol for screening materials, and they compare Italian regulations on quality control and good manufacturing practice of medical devices with foreign regulations.

Biocompatible Materials↗
PubMed2003

Quality control for the validation of extracorporeal photopheresis process using the Vilbert-Lourmat UV-A irradiation's system.

In agreement with good practices for therapeutic use of human cells, quality control has to be performed to valid the process of extracorporeal photopheresis (ECP) with the Vilbert-Lourmat system. Since no protocol exists, we evaluated a technique based on the measurement of the inhibition of mitogen (PHA, Con-A, OKT3)-induced proliferation, in 164 procedures from 16 patients. Whatever the pathology, we observed a high proliferation rate in most samples, and we obtained over 90% ECP-induced inhibition in as many as 94% of the cases. Since this approach proved to be relevant regarding our objective, a protocol for the ECP process validation is proposed.

Cell Division↗
PubMed2003

Quality control trial for human immunodeficiency virus type 1 drug resistance testing using clinical samples reveals problems with detecting minority species and interpretation of test results.

Between January and March 2000, a quality control panel for human immunodeficiency virus (HIV) drug resistance testing was analyzed by 20 laboratories in five countries. The panel consisted of three clinical samples with different drug resistance genotypes and phenotypes and one HIV-negative plasma. Participants were asked to report the methods used for amplification and sequencing, a list of drug resistance-associated mutations that were detected in the protease and reverse transcriptase of each sample, and an interpretation concerning the susceptibility or resistance to 14 antiretroviral drugs. A total of 22 genotypic data sets were generated, which showed an overall good technical quality except for three participants, who failed to report key mutations for drug resistance. Problems were encountered in three respects: (i). resistant minorities of L90M in the protease, which were determined to about 12% by real-time amplification, were only detected by one-fourth of the participants; (ii). newly described resistance mutations were frequently not reported; and (iii). interpretations of drug resistance-associated mutations varied widely, in particular for protease inhibitors. In some cases, different interpretations were caused by differences in the detection of resistant minorities, but even for the same genotypic profile, interpretations varied considerably. Similar discrepancies were revealed if current Web-based interpretation systems were used to predict drug resistance for samples of the proficiency panel. This indicates that a consensus for the interpretation of drug resistance-associated mutations is urgently needed.

Antiviral Agents↗
PubMed1987

Quality control material containing hemoglobin for blood gas and pH measurement: preparation of stroma-free hemoglobin solution.

A method for the preparation of stroma-free hemoglobin solution suitable for quality control of blood gas and pH measurements as well as hemoglobinometry, is described. Several methods were compared for purification and lysis of red blood cells. For separation of stroma from hemoglobin solution tangential cross-flow filtration has been used. Diluted hemoglobin solutions were concentrated using various forms of ultrafiltration as well as other methods. A precipitate removing procedure is introduced in which the pH is increased temporarily to 8.0 and the ionic strength is enhanced by adding 130 mmol NaCl per litre stroma-free hemoglobin solution, to remove a precipitate that was observed during tonometry at 37 degrees C in the pH-range 7.4-8.0 and when electrolytes were added to create a plasma-like composition of stroma-free hemoglobin solution. Tests were designed to quickly detect turbidity and precipitate. During storage at 4 degrees C no methemoglobin was formed in contrast with two other types of stroma-free hemoglobin solution, which formed appreciable amounts of methemoglobin within 40 days.

Blood Gas Analysis↗
PubMed1977

Quality control of small-volume sterile products.

A method for bacterial surveillance of small-volume sterile products in hospitals was developed and tested. The criteria for the method of quality control were to: (1) assure detection of contamination associated with touch, which could occur during the filling process; (2) be economically feasible; (3) be simple and easy to implement; and (4) be versatile in adapting to small-volume sterile packages with and without needles. Ten percent of each lot of prepackaged unit dose syringes is tested by filtration through a sterile micropore filter. The filter unit is incubated after fluid thioglycollate medium has been added. If turbidity or color change is found, further testing with blood agar and gram staining is performed to identify the organism. The effectiveness of the method was tested by adding E. coli to one lot within each of several lots tested of six products. The inoculated samples were stored under refrigeration for three days before testing. With one exception, the E. coli was detected in the samples. Growth did not occur in any of the noninoculated units. The apparent false negative result was believed to be caused by the bacteriostatic agent killing the organism during the three-day storage period.

Drug Contamination↗
PubMed1984

Interpretive criteria and tentative quality control limits for apalcillin disk susceptibility tests.

In vitro studies with 661 bacterial isolates were performed to establish interpretive criteria. In addition, a nine-laboratory study was performed to establish quality control limits for tests with 100-micrograms apalcillin disks and to confirm testing criteria for tests with 100-micrograms piperacillin disks. The two drugs were very similar, and nearly identical criteria were recommended for interpretation and for control of the two types of disks. Neither disk is recommended for testing Staphylococcus spp. or Haemophilus spp.; with other microorganisms, zone size limits of less than or equal to 13 mm (resistant) and greater than or equal to 18 mm (susceptible) are proposed for tests with 100-micrograms apalcillin disks.

Ampicillin↗
PubMed2005

Improving IMRT quality control efficiency using an amorphous silicon electronic portal imager.

An amorphous silicon electronic portal imaging device (EPID) has been investigated to determine its usefulness and efficiency for performing linear accelerator quality control checks specific to step and shoot intensity modulated radiation therapy (IMRT). Several dosimetric parameters were measured using the EPID: dose linearity and segment to segment reproducibility of low dose segments, and delivery accuracy of fractions of monitor units. Results were compared to ion chamber measurements. Low dose beam flatness and symmetry were tested by overlaying low dose beam profiles onto the profile from a stable high-dose exposure and visually checking for differences. Beam flatness and symmetry were also calculated and plotted against dose. Start-up reproducibility was tested by overlaying profiles from twenty successive two monitor unit segments. A method for checking the MLC leaf calibration was also tested, designed to be used on a daily or weekly basis, which consisted of summing the images from a series of matched fields. Daily images were coregistered with, then subtracted from, a reference image. A threshold image showing dose differences corresponding to > 0.5 mm positional errors was generated and the number of pixels with such dose differences used as numerical parameter to which a tolerance can be applied. The EPID was found to be a sensitive relative dosemeter, able to resolve dose differences of 0.01 cGy. However, at low absolute doses a reproducible dosimetric nonlinearity of up to 7% due to image lag/ghosting effects was measured. It was concluded that although the EPID is suitable to measure segment to segment reproducibility and fractional monitor unit delivery accuracy, it is still less useful than an ion chamber as a tool for dosimetric checks. The symmetry/flatness test proved to be an efficient method of checking low dose profiles, much faster than any of the alternative methods. The MLC test was found to be extremely sensitive to sudden changes in MLC calibration but works best with a composite reference image consisting of an average of five successive days' images. When used in this way it proved an effective and efficient daily check of MLC calibration. Overall, the amorphous silicon EPID was found to be a suitable device for IMRT QC although it is not recommended for dosimetric tests. Automatic procedures for low monitor unit profile analysis and MLC leaf positioning yield considerable time-savings over traditional film techniques.

Calibration↗
PubMed1981

[Quality control of hospital care or medical audit: non-juridical guarantee of quality].

After defining the meaning of "medical audit", i.e. control and guarantee of the quality of hospital treatment with absolutely no judgment connotation or idea of something that interferes in any way with the physician's professional freedom, aspects of the medical audit are summarised on the basis of American and Dutch experience. It is pointed out that the technical and medical aspects should be the initial considerations.

Hospitals↗
PubMed2004

[Effects of sperm and oocyte quality control on intracytoplasmic sperm injection (ICSI) in goats].

ABSTRACT Effects of sperm and oocyte quality control on the efficiency of ICSI of in vitro matured goat oocytes were studied in this paper. The results showed that when injected intracytoplasmically, spermatozoa from caput, corpus and cauda epididymidis resulted in similar rates of fertilization, cleavage and morulae/blastocysts, but when injected subzonally, spermatozoa from caput and corpus gave rise to significantly lower rates of fertilization and embryo development than spermatozoa from the cauda epididymidis and ejaculates. When dead spermatozoa collected from semen that had been preserved in different ways were used for ICSI, those dead from liquid storage at 20 degrees C for 24 h gave rise to the best, but those dead from liquid storage at 5 degrees C for 15 days produced the poorest fertilization and embryo development. When spermatozoa were treated with different concentrations of Triton X-100 before ICSI, significantly higher rates of fertilization, cleavage and morulae/blastocysts were obtained with 0.0005% Triton X-100 than with other concentrations and manual immobilization. Oocytes were classified as of good and poor qualities by treatment in hypertonic sucrose solution, and rates of fertilization and embryo development were significantly higher in the good than in the poor oocytes after ICSI. Post-injection activation of oocytes with either A23187 or ionomycin/6-DMAP significantly increased the rates of fertilization, cleavage and morulae/blastocysts after ICSI. It is therefore concluded that (i) epididymal maturation mainly endowed spermatozoa with the capacity to fuse with the egg plasma membrane; (ii) different methods of semen storage caused different impairment of sperm fertilizing capacity; (iii) pre-injection treatment of spermatozoa with proper concentrations of Triton X-100 might be used to replace manual immobilization for ICSI; (iv) oocyte quality was a major factor influencing the efficiency of ICSI; (v) post-injection activation treatment of oocytes improved fertilization and embryo development after ICSI.

Animals↗
PubMedDate not supplied

Evaluation of between-sample carryover on an automated coagulation instrument: recommendations for quality control procedures.

OBJECTIVE: To assess sample probe carryover levels in a modern automated coagulation analyzer. SETTING: Washoe Medical Center Clinical Laboratory, Reno, Nevada. DESIGN: Analysis of the relative degree of prolongation of coagulation assays using a sequential series of samples following a sample with inherent or added components with the potential for prolonging or accelerating coagulation when significant sample probe carryover is present. PARTICIPANTS: Not applicable. MAIN OUTCOME MEASURE: The extent of prolongation or acceleration of APTT or PT assays. RESULTS: The first sample positions assayed subsequent to specimans with potential accelerating or prolonging coagulation activity were affected by 3.9% to 17.8%. CONCLUSION: Results suggest that a potential exists in automated sampling coagulation analyzers. A mechanism for quality control analysis of carryover should be incorporated in automated probe coagulation analyzers. A suggested "1-2-1" control sequence is discussed as a possible quality assurance tool for measuring carryover within individual assay runs.

Anticoagulants↗