Gangliosides Block Aggregatibacter Actinomycetemcomitans Leukotoxin (LtxA)-Mediated Hemolysis

Aggregatibacter actinomycetemcomitans is an oral pathogen and etiologic agent of localized aggressive periodontitis. The bacterium is also a cardiovascular pathogen causing infective endocarditis. A. actinomycetemcomitans produces leukotoxin (LtxA), an important virulence factor that targets white blood cells (WBCs) and plays a role in immune evasion during disease. The functional receptor for LtxA on WBCs is leukocyte function antigen-1 (LFA-1), a β-2 integrin that is modified with N-linked carbohydrates. Interaction between toxin and receptor leads to cell death. We recently discovered that LtxA can also lyse red blood cells (RBCs) and hemolysis may be important for pathogenesis of A. actinomycetemcomitans. In this study, we further investigated how LtxA might recognize and lyse RBCs. We found that, in contrast to a related toxin, E. coli α-hemolysin, LtxA does not recognize glycophorin on RBCs. However, gangliosides were able to completely block LtxA-mediated hemolysis. Furthermore, LtxA did not show a preference for any individual ganglioside. LtxA also bound to ganglioside-rich C6 rat glioma cells, but did not kill them. Interaction between LtxA and C6 cells could be blocked by gangliosides with no apparent specificity. Gangliosides were only partially effective at preventing LtxA-mediated cytotoxicity of WBCs, and the effect was only observed when a high ratio of ganglioside:LtxA was used over a short incubation period. Based on the results presented here, we suggest that because of the similarity between N-linked sugars on LFA-1 and the structures of gangliosides, LtxA may have acquired the ability to lyse RBCs

Stellar Diameters and Temperatures VI. High angular resolution measurements of the transiting exoplanet host stars HD 189733 and HD 209458 and implications for models of cool dwarfs

We present direct radii measurements of the well-known transiting exoplanet host stars HD 189733 and HD 209458 using the CHARA Array interferometer. We find the limb-darkened angular diameters to be theta_LD = 0.3848 +/- 0.0055 and 0.2254 +/- 0.0072 milliarcsec for HD 189733 and HD 209458, respectively. HD 189733 and HD 209458 are currently the only two transiting exoplanet systems where detection of the respective planetary companion's orbital motion from high resolution spectroscopy has revealed absolute masses for both star and planet. We use our new measurements together with the orbital information from radial velocity and photometric time series data, Hipparcos distances, and newly measured bolometric fluxes to determine the stellar effective temperatures (T_eff = 4875 +/- 43, 6093 +/- 103 K), stellar linear radii (R_* = 0.805 +/- 0.016, 1.203 +/- 0.061 R_sun), mean stellar densities (rho_* = 1.62 +/- 0.11, 0.58 +/- 0.14 rho_sun), planetary radii (R_p = 1.216 +/- 0.024, 1.451 +/- 0.074 R_Jup), and mean planetary densities (rho_p = 0.605 +/- 0.029, 0.196 +/- 0.033 rho_Jup) for HD 189733 b and HD 209458 b, respectively. The stellar parameters for HD 209458, a F9 dwarf, are consistent with indirect estimates derived from spectroscopic and evolutionary modeling. However, we find that models are unable to reproduce the observational results for the K2 dwarf, HD 189733. We show that, for stellar evolutionary models to match the observed stellar properties of HD 189733, adjustments lowering the solar-calibrated mixing length parameter from 1.83 to 1.34 need to be employed

Principles of Periodontology

Periodontal diseases are among the most common diseases affecting humans. Dental biofilm is a contributor to the etiology of most periodontal diseases. It is also widely accepted that immunological and inflammatory responses to biofilm components are manifested by signs and symptoms of periodontal disease. The outcome of such interaction is modulated by risk factors (modifiers), either inherent (genetic) or acquired (environmental), significantly affecting the initiation and progression of different periodontal disease phenotypes. While definitive genetic determinants responsible for either susceptibility or resistance to periodontal disease have yet to be identified, many factors affecting the pathogenesis have been described, including smoking, diabetes, obesity, medications, and nutrition. Currently, periodontal diseases are classified based upon clinical disease traits using radiographs and clinical examination. Advances in genomics, molecular biology, and personalized medicine may result in new guidelines for unambiguous disease definition and diagnosis in the future. Recent studies have implied relationships between periodontal diseases and systemic conditions. Answering critical questions regarding host‐parasite interactions in periodontal diseases may provide new insight in the pathogenesis of other biomedical disorders. Therapeutic efforts have focused on the microbial nature of the infection, as active treatment centers on biofilm disruption by non‐surgical mechanical debridement with antimicrobial and sometimes anti‐inflammatory adjuncts. The surgical treatment aims at gaining access to periodontal lesions and correcting unfavorable gingival/osseous contours to achieve a periodontal architecture that will provide for more effective oral hygiene and periodontal maintenance. In addition, advances in tissue engineering have provided innovative means to regenerate/repair periodontal defects, based upon principles of guided tissue regeneration and utilization of growth factors/biologic mediators. To maintain periodontal stability, these treatments need to be supplemented with long‐term maintenance (supportive periodontal therapy) programs

Hur patienter med typ-2 diabetes reflekterar kring egenvård och information kring egenvård gällande fotsår

Abstract The aim of this study was to find out how patients with type-2 diabetes reflected on self-care and the information about selfcareactivites regarding diabetic footulcers. The study has a descriptive design with a qualitative approach. The study included fourteen patients with type-2 diabetes and they had footulcers related to their disease. They were recruited from different health centres in two cities in the Middle Sweden. The patients were interviewed and the interviewes were transcribed and worked up with qualitative content analysis. The authors recived seven subcategories which were sorted into two categories; reflection regarding information about self-care and reflection regarding self-care. The subcategories showed what the patients reflections were about information regarding self-care and the reflection regarding the self-care they performed. Reflection about information regarding self-care showed that approximately half of the interviewed patients were satisfied with the information they had got about the disease. They were also satisfied with the information about self-care they had recived from their diabetic nurse and doctor. In the category reflection regarding selfcareactivities you could see that the patients thought that selfcareactivities were important. They did not see the conection between a well peroformed self-care and that it reduced the risks of complications. Most of the patients were satisfied with the help they got from professional healthcare professionals.   Keyword:  Diabetic foot ulcers, information, self-care 

Tomorrow's elderly : A qualitative study about a new heterogeneous generation of elderly as recipients of elderly care

The purpose of the study is to describe and analyze how different professions in elderly care perceive the need for change and how they respond to challenges the elderly care is facing with an increasing heterogeneous generation of elderly in need of care. Further the study wants to describe and analyze differences between the professions perception of needs for change. Through this the study can contribute to increase knowledge in the area of an increasing heterogeneous generation of elderly people and its response to the needs of care. The empirical material has been collected through five semi-structured qualitative interviews where different employee positions in elderly care have been represented. One focus group has also been conducted. The empirical material from these interviews has thereafter been analyzed through the concept of salutogenic approach, forty talists and the third age. The result and conclusions shows that there are similar opinions about the importance of the quality of healthcare in the elderly care. The different employes work with the specific needs of the elderly in different ways and have overall similar goals. The results and conclusions confirm how communication lacks differently in the cooperation with each other. The employes believe that their interaction and cooperation with each other is important for the prospective work with future elderly care