Retrieval studies limitations

Well controlled manufacturing environment (trained personnel, formalized line clearance, adequate documentation, and verification practices) Customized and study-specific labeling and packaging procedures Sponsor-controlled relabeling and product retrieval operations Limit investigator site manipulation of CTM and labeling... 

Abstract The biocompatibihty, biofunctionahty and biostability of a prosthesis, its degradation and the host response are determined throngh an implant retrieval stndy.This chapter focnses on varions aspects of analyzing retrieved biotextile implants. Sample preparation techniques, analytical test methods and different test standards are reviewed. Some precautions and the limitations of implant retrieval studies are also discussed. 

Retrieval study samples from human beings are more difficult to obtain and are usually available as a result of an unscheduled reoperation or autopsy, either of which could be due to device failure or to some totally unrelated cause. Implants retrieved at reoperation are generally in a poorer condition since they are often collected in response to emergency surgery where the patient is the primary concern and the preservation and integrity of the biotextile explant is of limited interest. It is therefore mandatory to include with every clinically retrieved sample some explanation... 

Thus, retrieval studies have both their own advantages and limitations whether using animal models or human clinical trials. There is always a possibility that the tests in the retrieval studies are poorly chosen, that the results are over-estimated or under-estimated, that the animal model selected may not be the most appropriate, or that the human subjects included in the clinical trial are not typical or representative of the particular pathology under investigation. 

Based on a limited number of retrieval studies, the clinical experience with EtO-steriUzed UHMWPE components has thus far been favorable [13, 28]. In a study by White et al. [28], researchers compared the surface damage... 

Archived electronic data are to be treated no differently to archived paper data. An archivist should be assigned, access should be limited to authorized personnel, data should be archived at the completion of the study, and all material should be indexed to permit expedient retrieval. Depending on the medium used for storage, an area within the facility may be needed with specific environmental controls to maintain the integrity of electronic data. This should be specified in the data storage SOPs. Environmental conditions need to be monitored in the archives where electronic media are stored. 

Figure 5.3 Diagram depicts the further-designed studies to test our hypothesis with respect to standardization of immunohistochemistry based on the antigen retrieval technique exemplified in a multiple direction to draw a conclusion, (a) Periods of formalin fixation, (b) Variable delay of fixation, (c) Storage of FFPE tissue blocks or sections, (d) Variable thickness of FFPE tissue sections, (e) Other variable conditions of processing FFPE tissue blocks. The stereoscopic frame of a cube represents the reliable limitation of quantitative IFIC demonstrated by serial studies as recommended in the text. Reproduced with permission from Shi et al., J. Histochem. Cytochem. 2007 55 105-109.

That precursors are frequently observed in accident trajectories was stated in the previous Section. In this Section 17 recent accidents in the Dutch chemical process industry are taken and their accompanying precursors and ineffective control processes in the companies identified. This study is executed from hindsight using limited accident information which is the reason for adapting the analysis protocol so that the results of most stages can still be retrieved. 

For all 17 accidents of this study, precursors could be identified. None of the 17 accidents could be classified as unforeseen . A total number of 39 precursors were identified in these 17 accidents which seems extremely low compared to normal accident analysis experience. Detailed accident analysis normally retrieves dozens of near misses and deviations leading to the final accident (e.g. van der Schaaf (Schaaf van der, 1992)), implying the existence of many more precursors. However, the limited amount of detailed information present in the FACTS database is the restricting factor here. The FACTS database reflects the kind of accident information companies and government agencies collect. It demonstrates clearly that detailed information about the period before the accident is not often collected. 

Space shall be provided for archives, limited to access by authorized personnel only, for the storage and retrieval of all raw data and specimens from completed studies. 

The GLP standards state that all raw data, documentation, records, protocols, specimens, and final reports generated as a result of a study shall be retained. Specimens do not need to be retained after QA verification. Storage conditions must allow for expedient retrieval with an indexing system. Access to the archived records must be limited to authorized personnel. 

This need may arise when a limited number of slides is available. For this type of study, heat-induced antigen retrieval should be carried out only once. One such treatment lasts for many months. Repeated use of antigen retrieval tends to cause background staining. Such an approach has been successfully used for staining epithelial membrane antigens and cytokeratin in the tonsil tissue fixed with Bouin s fixative (Roche et al 2000). 

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