Pneumococcal immune adherence to human erythrocytes

BACKGROUND: Human red blood cells bind various C3b-coated microorganisms via their C3b/CR1 receptor, a phenomenon referred to as immune adherence. The aim of the present study was to measure pneumococcal adherence to human red blood cells by flow cytometry and to study kinetic aspects of this binding. MATERIAL AND METHODS: We quantified pneumococcal adherence to human erythrocytes by FACS analysis and tested the involvement of antibodies and complement activation in this process. RESULTS: Pneumococci are able to bind to human red blood cells in the presence of human serum. Coating with C3b/C4b appeared obligatory for pneumococcal adherence to red blood cells. The ligand on erythrocytes was confirmed to be complement receptor 1. Kinetic studies showed that innate (mannose-binding lectin) and specific immune factors (IgG antibodies) contributed to the binding of C3b-coated pneumococci to human erythrocytes. After initial binding, serum-derived factor I was found to induce bacterial detachment from the erythrocyte. CONCLUSIONS: Pneumococci are able to adhere to red blood cells. Both the classical and lectin complement pathways are important for optimal C3b-coating of pneumococci for immune adherence. Bound pneumococci are detached from red blood cells by factor I. These findings are in line with the hypothesis of immune adherence in which human erythrocytes are able to bind pneumococci and target the bacteria to the reticulo-endothelial system in the spleen.     

Characterization of human skin equivalents developed at body's core and surface temperatures

Human skin equivalents (HSEs) are in vitro developed three‐dimensional models resembling native human skin (NHS) to a high extent. However, the epidermal lipid biosynthesis, barrier lipid composition, and organization are altered, leading to an elevated diffusion rate of therapeutic molecules. The altered lipid barrier formation in HSEs may be induced by standardized culture conditions, including a culture temperature of 37°C, which is dissimilar to skin surface temperature. Therefore, we aim to determine the influence of culture temperature during the generation of full thickness models (FTMs) on epidermal morphogenesis and lipid barrier formation. For this purpose, FTMs were developed at conventional core temperature (37°C) or lower temperatures (35°C and 33°C) and evaluated over a time period of 4 weeks. The stratum corneum (SC) lipid composition was analysed using advanced liquid chromatography coupled to mass spectrometry analysis. Our results show that SC layers accumulated at a similar rate irrespective of culture temperature. At reduced culture temperature, an increased epidermal thickness, a disorganization of the lower epidermal cell layers, a delayed early differentiation, and an enlargement of granular cells were detected. Interestingly, melanogenesis was reduced at lower temperature. The ceramide subclass profile, chain length distribution, and level of unsaturated ceramides were similar in FTMs generated at 37°C and 35°C but changed when generated at 33°C, reducing the resemblance to NHS. Herein, we report that culture temperature affects epidermal morphogenesis substantially and to a lesser extent the lipid barrier formation, highlighting the importance of optimized external parameters during reconstruction of skin.     

Proposed outcome measures for prospective clinical trials in juvenile idiopathic arthritis–associated uveitis: A consensus effort from the multinational interdisciplinary working group for uveitis in childhood

Objective

To develop a set of core outcome measures for use in randomized controlled trials (RCTs) and longitudinal observational studies in juvenile idiopathic arthritis (JIA)–associated uveitis.

Methods

The literature relating to outcome measures used in studies of uveitis in childhood and adolescence was reviewed. A set of core outcomes and domains was established using the Delphi process. This was reviewed by a representative multinational interdisciplinary working group. Nominal group technique consensus was reached on face and content validity of the range and content of the domains. The outcomes and the appropriate instruments for uveitis trials were adapted to the age ranges of patients with JIA‐associated uveitis.

Results

Consensus was reached that data should be reported at defined time points in longitudinal studies with patients stratified by prognostic markers. Visual acuity testing should be age appropriate. The severity of uveitis (measured as anterior chamber cell grade) and duration of active inflammation should be documented. Visually significant structural complications should be recorded and quantified with standard measures. The responses to treatment and corticosteroid‐sparing effects of treatment should be documented. Patient‐reported disease activity and age‐specific uveitis‐related quality of life should be reported using appropriate questionnaires.

Conclusion

The proposed outcome measures in JIA‐associated uveitis should aid in the standardization and comparison of future RCTs of the treatment regimens for this disease. The proposed outcome measures will be verified in a prospective validation study.     

Carotid stiffness and the risk of new vascular events in patients with manifest cardiovascular disease. The SMART study.

AIMS: To study whether arterial stiffness is related to risk of new vascular events in patients with manifest arterial disease and to examine whether this relation varies between patients who differ with respect to baseline vascular risk, arterial stiffness, or systolic blood pressure (SBP). METHODS AND RESULTS: The study was performed in the first consecutive 2183 patients with manifest arterial disease enrolled in the SMART study (Second Manifestations of ARTerial disease), a cohort study among patients with manifest arterial disease or cardiovascular risk factors. Common carotid distension (i.e. the change in carotid diameter in systole relative to diastole) was measured at baseline by ultrasonography. With the distension, several stiffness parameters were determined. In the entire cohort, none of the carotid artery stiffness parameters was related to the occurrence of vascular events. However, decreased stiffness was related to decreased vascular risk in subjects with low baseline SBP. The relation of carotid stiffness with vascular events did not differ between tertiles of baseline risk and carotid stiffness. CONCLUSION: Carotid artery stiffness is no independent risk factor for vascular events in patients with manifest arterial disease. However, in patients with low SBP, decreased carotid stiffness may indicate a decreased risk of vascular events.     

Exploring the Development of Existing Sex Education Programmes for People with Intellectual Disabilities: An Intervention Mapping Approach

Background

People with intellectual disabilities face barriers that affect their sexual health. Sex education programmes have been developed by professionals working in the field of intellectual disabilities with the aim to overcome these barriers. The aim of this study was to explore the development of these programmes.

Methods

Sex education programmes geared to people with intellectual disabilities were examined in the context of the Intervention Mapping protocol. Data were obtained via interviews with the programme developers.

Results

All programmes lack specific programme outcomes, do not have a theoretical basis, did not involve members of relevant groups in the development process and lack systematic evaluation.

Conclusions

Based on our findings and the literature, we conclude that these programmes are unlikely to be effective. Future programmes should be developed using a more systematic and theory‐ and evidence‐based approach.     

Evaluation of a preparation depth controlling device: a pilot study.

OBJECTIVE: To define the reproducibility and accuracy of the Prepometer device (Hager & Werken) and to correlate the measured electrical resistance with the remaining dentin thickness. METHOD AND MATERIALS: In vivo standardized cavities were made on the buccal side in the cervical region of 12 intact teeth. Measurements with the Prepometer were completed before tooth extraction. After extraction, in vitro measurements of the remaining dentin thickness were performed using a microfocus-computerized tomography scanner. These in vitro scan data were compared with the in vivo measurements, and correlation coefficients calculated. The intra- and interinvestigator variability were defined, using a paired 2-tailed Student t test. The level of significance was set at 5%. RESULTS: Although both the intra- and interinvestigator variability scored well, there was no clear correlation between the Prepometer measurements and the remaining dentin thickness. Because the device determines the electrical resistance of the dentin, which is related to dentin permeability, real remaining dentin thickness cannot be measured. A reasonable safety zone (3 of 12 teeth scored false negative and 1 of 12 teeth scored false positive) in terms of remaining dentin thickness was observed. CONCLUSIONS: The Prepometer, a device developed to screen dentin-surface permeability by measuring its electrical resistance, was shown to be reproducible in its use. However, electrical resistance was shown not to correlate with dentin thickness. Although the Prepometer might help to estimate the risk of pulp injury after tooth preparation, its effectiveness still remains to be proven in a randomized clinical trial.     

A Cross-Section Device To Improve Visualization of Fluorescent Probe Penetration into the Skin by Confocal Laser Scanning Microscopy

Pharmaceutical Research -     

The in vivo transport of elastic vesicles into human skin: effects of occlusion, volume and duration of application.

In the present study, several aspects of elastic vesicle transport into human skin were investigated in vivo. Surfactant-based elastic vesicles were applied onto human skin in vivo and subsequently a series of tape-strippings were performed, which were visualised by freeze fracture electron microscopy. Factors of investigation for non-occlusive treatment were the duration of application and the volume of application. In addition, occlusive vs. non-occlusive application was studied. The results have shown a fast penetration of intact elastic vesicles into the stratum corneum after non-occlusive treatment, frequently via channel-like regions. Intact vesicles could reach the ninth tape-strip after the 1-h non-occlusive treatment. After the 4-h treatment, vesicle material could be found in the 15th tape-strip. However, micrographs of the 4-h treatment showed extensive vesicle fusion, both at the skin surface as well as in the deeper layers of the stratum corneum. A higher volume of application resulted in an increase in the presence of vesicle material found in the deeper layers of the stratum corneum. Micrographs after occlusive treatment revealed very few intact vesicles in the deeper layers of the stratum corneum, but the presence of lipid plaques was frequently observed. Furthermore, we have proposed a hypothesis that the channel-like regions represent imperfections within the intercellular lipid lamellae in areas with highly undulating cornified envelopes.