Practical guidelines for process validation and process control of white cell-reduced blood components: report of the Biomedical Excellence for Safer Transfusion (BEST) Working Party of the International Society of Blood Transfusion (ISBT)

Background: The increased use of white (WBC)-reduced blood components has prompted many institutions to develop quality assurance programs directed to such component preparation processes. For consistent preparation of WBC-reduced blood components that meet clinical needs as well as national standards, a program of process validation and control should be instituted. This involves controlling key factors that affect WBC reduction as well as periodic monitoring of the residual cellular content of components. Practical guidelines for the implementation of such a program are provided. Study Design and Methods: A program involving three phases of monitoring was developed by individuals belonging to an international working party of the International Society of Blood Transfusion. Results: The first phase, process validation, evaluates a minimum of 20 consecutive units (a minimum of 60 units when nonparametric measurements are used) to document the successful local implementation of a new or substantially modified process. Ongoing process control employing Levey-Jennings type control charts is used to demonstrate that the process remains stable over time. Process capability assessment and conformance with standards are evaluated once residual WBCs are counted in a sufficient number of units. This enables a facility to claim with a specified degree of confidence that a stated proportion of WBC-reduced units will meet national standards. Two approaches to determine the number of units that should be selected for counting are presented. The first approach considers units as either acceptable or not acceptable and assumes that the distribution of failed (or nonconforming) units approximates the Poisson distribution. The second approach takes into consideration the observed WBC content of the tested units, with the assumption that the residual WBC content in WBC-reduced components follows a lognormal distribution. A method to assess the lognormal distribution of residual WBCs is presented. Specific tables based on each of these approaches are provided to guide the reader in the design of a program that will verify conformance with any national standard at specific confidence levels. The approach can be generalized to other process control applications. Conclusion: Guidelines are presented for process validation, process control, and assessment of conformance in the production of WBC-reduced blood components. Policy makers retain the responsibility to establish, on the basis of the expected use of WBC- reduced components, requirements for the frequency of testing and for the proportion of prepared units that are expected with a stated degree of confidence to meet the standards. Facilities preparing WBC-reduced components can monitor key factors that influence the preparation of WBC-reduced blood, can periodically assess their conformance with the standards, and can intervene to correct adverse changes in the process. This approach can be used to ensure the consistent quality of WBC- reduced blood components.     

Sampling errors and the precision associated with counting very low numbers of white cells in blood components

Attention to the accurate and precise measurement of the white cell (WBC) content of transfused products has risen in response to awareness of the potential benefits of WBC-depleted components and the development of technical capabilities to produce these components. The techniques thus far reported have focused on the reliability of detecting a WBC, provided it is present in the test system. The likelihood of selecting a WBC from the product of interest for counting in the analytical system--that is, the sampling error--must also be considered. The occurrence of a WBC in a WBC-depleted component is a rare event and may be modeled with the binomial or the Poisson distribution. Several assay techniques were analyzed by using these distribution models to determine the confidence intervals of the WBC content. The 95-percent confidence intervals spanned more than 2 logs10 for some methods at 3 x 10(5) WBCs per product. It is concluded that the reporting of WBC content for research provides not only the estimate of the mean but also a confidence interval for this estimate. Quality control procedures should be designed to verify that the WBC content is less than the targeted amount and should provide an associated statement of confidence.     

A study of confidential unit exclusion

The effectiveness of the confidential unit exclusion (CUE) procedure recommended by the Food and Drug Administration has been questioned by the blood banking community. The purpose of this study was to determine whether donors were informing the blood center correctly regarding the disposition (transfuse or do not transfuse) of their donated blood. A letter explaining the confidential study and requesting permission to send the participant a questionnaire noting his or her self-exclusion choice was mailed to 230 donors who had chosen transfuse and 276 donors who had chosen do not transfuse. After consent was obtained, participants were sent a second packet and asked to indicate whether they had chosen correctly and, if not, to identify reasons for that incorrect choice. A seven-word terminology quiz made up of words from the CUE form was also enclosed. All participants who had chosen transfuse indicated that this was the correct choice. Approximately 50 percent of those who had chosen do not transfuse indicated that this was an incorrect choice; the most common reason was that "I was not paying attention." The most frequently misunderstood term was "confidential." Donors who chose do not transfuse had a significantly higher rate of error on the terminology quiz (p less than 0.01) than did those who chose transfuse.     

Progress in laparoscopic anatomy research: A review of the Chinese literature

The development of laparoscopic surgery has generated the new field of study, laparoscopic anatomy. This article reviews the reported literature on laparoscopic anatomy and explores how it has evolved along with advances in abdominal surgery. In addition, the principal concerns in current laparoscopic anatomy research are discussed, including: (1) types of special adjacent anatomical structures; and (2) special surgical planes and anatomical landmarks. Understanding of systematic laparoscopic anatomy can pr...     

Rencontre de modèles cliniques et robotiques. Du saut entre les organisations psychiques

Clinical models of the mental system and robotic models of artificial thinking show analogies which enable us to compare them. These encounters facilitate the study of the jumps between the various mental organisations. Actually, these jumps are easily observed in current clinic. It is a matter of commonplace observations (the various organisations), of means reflecting them (ladder and systematical module), of natural jumps in mental disturbances (periods of evolution of mental disturbances, structuring of disturbances, integration of the various levels of organisation), and of internal gaps in the system during the formation of the meaning process. Correspondingly, robotics emphasize the specific principles of a system of artificial thinking: the internal structuring of the system, the relations with the external world and self-control; these principles are directly analogous with clinical facts. Furthermore, their realisation shows an efficient structuring of these jumps allowing a better understanding of them. These comparisons show the interest of modeling in three co-active and indissociable levels (biologic, semantic, and linguistic), of taking account of gaps and regulating factors, of refining means of thinking (particularly of intuition and of the matrices of logic knowledge) and of a better grasp of pathologic phenomena.     

Exploring the oral bacterial flora: current status and future directions

Oral Diseases (2010) 16 , 136–145 Objective: The oral cavity forms an indispensable part of the human microbiome, for its unique and diverse microflora distributed within various niches. While majority of these organisms exhibit commensalism, shifts in bacterial community dynamics cause pathological changes within oral cavity and distant sites. The aim of this review was to appraise the current and emerging methods of detecting bacteria of the oral cavity paying particular attention to the cultivation independent methods. Design: Literature pertaining to cultivation based and cultivation independent methods of oral bacterial identification was reviewed. Methods: The specific advantages and disadvantages of cultivation based, microscopic, immunological and metagenomic identification methods were appraised. Results: Because of their fastidious and exacting growth requirements, cultivation based studies grossly underestimate the extent of bacterial diversity in these polymicrobial infections. Culture independent methods deemed more sensitive in identifying difficult to culture and novel bacterial species. Conclusion: Apart from characterizing potentially novel bacterial species, the nucleic acid sequence data analyzed using various bioinformatics protocols have revealed that there are in excess of 700 bacterial species inhabiting the mouth. Moreover, the latest pyrosequencing based methods have further broadened the extent of bacterial diversity in oral niches.     

The effects of concurrent administration of +/-3,4-methylenedioxymethamphetamine and cocaine on conditioned place preference in the adult male rat

Conditioned place preference (CPP), a commonly used model for studying the role of contextual cues in drug reward and drug seeking, was employed to explore possible behavioral interactions between (+/-)3,4-methylenedioxymethamphetamine (MDMA; "ecstasy") and cocaine. On each of four occasions, adult male rats received one of three doses of MDMA (0 mg/kg, 5 mg/kg, 10 mg/kg; administered subcutaneously [s.c.]) combined with one of three doses of cocaine (0 mg/kg, 2.5 mg/kg, 5 mg/kg; administered intraperitoneally [i.p.]), and were then tested in a CPP paradigm. The results showed MDMA-induced CPP at a unit dose of 5 mg/kg, but at the 10 mg/kg dose there was a return to baseline (control) performance levels. For cocaine alone, CPP increased in a linear fashion as the drug dose was increased. Concurrent administration resulted in antagonism of each drug, but there was evidence that this pattern was reversible at higher doses of the respective drugs. These data are instructive insofar as they suggest that the behavioral and neurochemical effects of MDMA and cocaine presented in isolation are dramatically altered when the two drugs are presented in combination.     

A review of studies of parent-child communication about sexuality and HIV/AIDS in sub-Saharan Africa

Parent-child sexuality communication has been identified as a protective factor for adolescent sexual and reproductive health, including HIV infection. The available literature on this topic in sub-Saharan Africa is increasing; however a systematic review of studies has not been conducted. This article reviews the literature in the area of parental or caregiver and child communication about sexuality and HIV/AIDS in sub-Saharan Africa. A review of peer reviewed literature published between 1980 and April 2011 was conducted. Communication process studies investigating the frequency, content, style, tone of discussions, preferences, as well as associations with and barriers to sexuality communication are reviewed. In addition, studies which examine behavioral associations with parent-child sexuality communication, and intervention studies to improve parent-child sexuality communication are examined. The findings from process studies suggest wide variation in terms of frequency of discussions, with a range of socio-demographic and other factors associated with sexuality communication. Overall, findings demonstrate that discussions tend to be authoritarian and uni-directional, characterized by vague warnings rather than direct, open discussion. Moreover, parents and young people report a number of barriers to open dialogue, including lack of knowledge and skills, as well as cultural norms and taboos. Findings are less clear when it comes to associations between parental communication and adolescent sexual activity and contraception use. However, nascent indications from intervention research suggest positive findings with increases in frequency and comfort of discussions, among other outcomes. Gaps in the research are identified and discussed with implications for future studies.