Experimental Human Cell and Tissue Models of Pemphigus

Pemphigus is a chronic mucocutaneous autoimmune bullous disease that is characterized by loss of cell-cell contact in skin and/or mucous membranes. Past research has successfully identified desmosomes as immunological targets and has demonstrated that acantholysis is initiated through direct binding of IgG. The exact mechanisms of acantholysis, however, are still missing. Experimental model systems have contributed considerably to today's knowledge and are still a favourite tool of research. In this paper we will describe to what extent human cell and tissue models represent the in vivo situation, for example, organ cultures of human skin, keratinocyte cultures, and human skin grafted on mice and, furthermore, how suitable they are to study the pathogenesis of pemphigus. Organ cultures closely mimic the architecture of the epidermis but are less suitable to answer posed biochemical questions. Cultured keratinocyte monolayers are convenient in this respect, but their desmosomal make-up in terms of adhesion molecules does not exactly reflect the in vivo situation. Reconstituted skin is a relatively new model that approaches organ culture. In models of human skin grafted on mice, acantholysis can be studied in actual human skin but now with all the advantages of an animal model

Type VII Collagen Expression in the Human Vitreoretinal Interface, Corpora Amylacea and Inner Retinal Layers

Type VII collagen, as a major component of anchoring fibrils found at basement membrane zones, is crucial in anchoring epithelial tissue layers to their underlying stroma. Recently, type VII collagen was discovered in the inner human retina by means of immunohistochemistry, while proteomic investigations demonstrated type VII collagen at the vitreoretinal interface of chicken. Because of its potential anchoring function at the vitreoretinal interface, we further assessed the presence of type VII collagen at this site. We evaluated the vitreoretinal interface of human donor eyes by means of immunohistochemistry, confocal microscopy, immunoelectron microscopy, and Western blotting. Firstly, type VII collagen was detected alongside vitreous fibers6 at the vitreoretinal interface. Because of its known anchoring function, it is likely that type VII collagen is involved in vitreoretinal attachment. Secondly, type VII collagen was found within cytoplasmic vesicles of inner retinal cells. These cells resided most frequently in the ganglion cell layer and inner plexiform layer. Thirdly, type VII collagen was found in astrocytic cytoplasmic inclusions, known as corpora amylacea. The intraretinal presence of type VII collagen was confirmed by Western blotting of homogenized retinal preparations. These data add to the understanding of vitreoretinal attachment, which is important for a better comprehension of common vitreoretinal attachment pathologies

CGR-CUSUM: a continuous time generalized rapid response cumulative sum chart

Rapidly detecting problems in the quality of care is of utmost importance for the well-being of patients. Without proper inspection schemes, such problems can go undetected for years. Cumulative sum (CUSUM) charts have proven to be useful for quality control, yet available methodology for survival outcomes is limited. The few available continuous time inspection charts usually require the researcher to specify an expected increase in the failure rate in advance, thereby requiring prior knowledge about the problem at hand. Misspecifying parameters can lead to false positive alerts and large detection delays. To solve this problem, we take a more general approach to derive the new Continuous time Generalized Rapid response CUSUM (CGR-CUSUM) chart. We find an expression for the approximate average run length (average time to detection) and illustrate the possible gain in detection speed by using the CGR-CUSUM over other commonly used monitoring schemes on a real-life data set from the Dutch Arthroplasty Register as well as in simulation studies. Besides the inspection of medical procedures, the CGR-CUSUM can also be used for other real-time inspection schemes such as industrial production lines and quality control of services. Analysis and Stochastic

Human retinal Müller cells synthesize collagens of the vitreous and vitreoretinal interface in vitro

Purpose: To investigate the capacity of cultured Muller cells to synthesize collagens, since previous studies indicated that Muller cells could be involved in collagen remodeling at the vitreoretinal border in adult human eyes. Methods: Spontaneously immortalized cultured human Muller cells were analyzed for the presence of mRNA of types I-VII, IX, XI, and XVII collagen by RT-PCR. Furthermore, Muller cells were immunocytochemically stained for light microscopic (LM) evaluation of these collagens and their main characteristics. Finally, cell extracts and culture medium were evaluated by western blot (WB) analysis using anticollagen antibodies. Results: Cultured Muller cells contained mRNA for types I-VII, IX, and XI collagen, but not for type XVII collagen. LM and WB confirmed the intracellular expression of all the above-mentioned collagens with the exception of type XVII. Collagen secretion into the medium was established for types I-VII, IX, and XI collagen. Conclusions: Cultured Muller cells can synthesize internal limiting lamina and vitreous collagens. Possible collagen production by Muller cells could explain and expand on previous in vivo morphological findings in the embryonic and postnatal period and in pathologic conditions

Feasibility and reliability of PRISMA-Medical for specialty-based incident analysis

Aims and objectives: In this study, the feasibility and reliability of the Prevention Recovery Information System for Monitoring and Analysis (PRISMA)-Medical method for systematic, specialty-based analysis and classification of incidents in the neonatal intensive care unit (NICU) were determined. Methods: After the introduction of a Neonatology System for Analysis and Feedback on Medical Events (NEOSAFE) in eight tertiary care NICUs and one paediatric surgical ICU, PRISMA-Medical was started to be used to identify root causes of voluntary reported incidents by multidisciplinary unit patient safety committees. Committee members were PRISMA-trained and familiar with the department and its processes. In this study, the results of PRISMA-analysis of incidents reported during the first year are described. At t¿=¿3 months and t¿=¿12 months after introduction, test cases were performed to measure agreement at three levels of root cause classification using PRISMA-Medical. Inter-rater reliability was determined by calculating generalised ¿ values for each level of classification. Results: During the study period, 981 out of 1786 eligible incidents (55%) were analysed for underlying root causes. In total, 2313 root causes were identified and classified, giving an average of 2.4 root causes for every incident. Although substantial agreement (¿ 0.70–0.81) was reached at the main level of root cause classification of the test cases (discrimination between technical, organisational and human failure) and agreement among the committees at the second level (discrimination between skill-based, rule-based and knowledge-based errors) was acceptable (¿ 0.53–0.59), discrimination between rule-based errors (the third level of classification) was more difficult to assess (¿ 0.40–0.47). Conclusion: With some restraints, PRISMA-Medical proves to be both feasible and acceptably reliable to identify and classify multiple causes of medical events in the NICU

Specialty-based, voluntary incident reporting in neonatal intensive care: description of 4846 incident reports

OBJECTIVES: To examine the characteristics of incidents reported after introduction of a voluntary, non-punitive incident reporting system for neonatal intensive care units (NICUs) in the Netherlands; and to investigate which types of reported incident pose the highest risk to patients in the NICU. DESIGN: Prospective multicentre survey. METHODS: Voluntary, non-punitive incident reporting was introduced in eight level III NICUs and one paediatric surgical ICU. An incident was defined as any unintended event which (could have) reduced the safety margin for the patient. Multidisciplinary, unit-based patient safety committees systematically collected and analysed incident reports, and assigned risk scores to each reported incident. Data were centrally collected for specialty-based analysis. This paper describes the characteristics of incidents reported during the first year. Bivariate logistic regression analysis was conducted to identify high-risk incident categories. RESULTS: There were 5225 incident reports on 3859 admissions, of which 4846 were eligible for analysis. Incidents with medication were most frequently reported (27%), followed by laboratory (10%) and enteral nutrition (8%). Severe harm was described in seven incident reports, and moderate harm in 63 incident reports. Incidents involving mechanical ventilation and blood products were most likely to be assigned high-risk scores, followed by those involving parenteral nutrition, intravascular lines and medication dosing errors. CONCLUSIONS: Incidents occur much more frequently in Dutch NICUs than has been previously observed, and their impact on patient morbidity is considerable. Reported incidents concerning mechanical ventilation, blood products, intravascular lines, parenteral nutrition and medication dosing errors pose the highest risk to patients in the NIC

Clinical osteoarthritis of the hip and knee and fall risk: The role of low physical functioning and pain medication

Objective: Several studies have found an increased fall risk in persons with osteoarthritis (OA). However, most prospective studies did not use a clinical definition of OA. In addition, it is not clear which factors explain this risk. Our objectives were: (1) to confirm the prospective association between clinical OA of the hip and knee and falls; (2) to examine the modifying effect of sex; and (3) to examine whether low physical performance, low physical activity and use of pain medication are mediating these relationships. Methods: Baseline and 1-year follow-up data from the European Project on OSteoArthritis (EPOSA) were used involving pre-harmonized data from five European population-based cohort studies (ages 65 85, n = 2535). Clinical OA was defined according to American College of Rheumatology (ACR) criteria. Falls were assessed using self-report. Results: Over the follow-up period, 27.7% of the participants fell once or more (defined as faller), and 9.8% fell twice or more (recurrent faller). After adjustment for confounding, clinical knee OA was associated with the risk of becoming a recurrent faller (relative risk=1.55; 95% confidence interval: 1.10 2.18), but not with the risk of becoming a faller. No associations between clinical hip OA and (recurrent) falls were observed after adjustment for confounding. Use of opioids and analgesics mediated the associations between clinical OA and (recurrent) falls, while physical performance and physical activity did not. Conclusion: Individuals with clinical knee OA were at increased risk for recurrent falls. This relationship was mediated by pain medication, particularly opioids. The fall risk needs to be considered when discussing the risk benefit ratio of prescribing these medicationsSources of support: The Longitudinal Aging Study Amsterdam (LASA) is financially supported by the Dutch Ministry of Health, Welfare and Sports (grant no 311669, grant recipient D.J.H. Deeg). The Pe~nagrande study was partially supported by the National Fund for Health Research (Fondo de Investigaciones en Salud) of Spain (grant no FIS PI 05/1898; FIS RETICEF RD06/0013/1013 and FIS PS09/02143, grant recipients A. Otero, M.V. Castell). The Hertfordshire Cohort Study is supported by the Medical Research Council of Great Britain, Versus Arthritis, the British Heart Foundation and the International Osteoporosis Foundation (grant no MRC_MC_UP_A620_1014, grant recipients C. Cooper, E. Dennison). The Italian cohort was supported by the National Research Council of Italy (CNR), Research Project “Aging: molecular and technological innovations for improving the health of the elderly population" (Prot. MIUR 2867, grant recipient: S. Maggi). The Swedish Twin Registry is managed by Karolinska Institutet and receives funding through the Swedish Research Council (grant no 2017-00641, grant recipient Karolinska Institutet