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| 2. |
- Braide, Magnus, 1955, et al.
(författare)
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Microvascular behavior and effects of sonazoid microbubbles in the cremaster muscle of rats after local administration.
- 2006
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Ingår i: Journal of ultrasound in medicine : official journal of the American Institute of Ultrasound in Medicine. - 0278-4297. ; 25:7, s. 883-90
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: The purpose of this study was to observe Sonazoid perfluorobutane microbubbles (GE Healthcare, Amersham, Buckinghamshire, England) in and their effects on the cremaster capillary microcirculation of rats. METHODS: Sonazoid (0.3 x 10(9) microbubbles in 0.5 mL) was observed by intravital microscopy in the cremaster muscle after retrograde administration into the femoral artery of 6 animals. Microbubble and microvessel diameters and blood flow velocities and the overall mean and SD of the 1-minute volume flow through the microscopic field were calculated from the 2 to 4 capillaries observed in the field of each animal. Fluorescein isothiocyanate-dextran leakage was used to assess extravasation after microbubble passage. RESULTS: seconds, respectively, before they were released and capillary flow normalized. No microbubble size changes, damming, or coalescence of bubbles and no changes in microvessel diameter or microvascular blood flow velocities, volume flow, or perfusion heterogeneity occurred during or after the passage of the Sonazoid suspension or the vehicle. No fluorescein isothiocyanate-dextran leakage was observed. CONCLUSIONS: The passage of Sonazoid bubbles at concentrations higher than those expected after intravenous administration of the Sonazoid did not durably impair microvascular perfusion, structural integrity, or macromolecular retention in the rat cremaster muscle. The duration of discrete capillary obstructions was short and in all cases comparable with that of naturally occurring leukocyte plugging.
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- Carstensen, Ole, et al.
(författare)
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The validity of a questionnaire-based epidemiological study of occupational dermatosis
- 2006
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Ingår i: Contact Dermatitis. - : Wiley. - 0105-1873 .- 1600-0536. ; 55:5, s. 295-300
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Tidskriftsartikel (refereegranskat)abstract
- The aim of this study was to evaluate the validity of a questionnaire and medical anamnesis to identify persons with dermatitis in an occupational setting. The design was a clinical epidemiological cross-sectional study. The study was performed between the second and fourth week of January 2001. A questionnaire was followed a week later by a medical occupational interview and a clinical dermatological examination, including a comprehensive patch test with potential workplace chemicals. The anamnesis and the clinical examination were made independently by occupational and dermatological physicians, and the skin examination was performed blinded to anamnestic data. The setting was the mother plants of a Danish-based international company producing wind turbine systems. The study population was a workplace cohort, highly exposed to epoxy resin systems and other chemicals, and totalled 724 production workers at 4 facilities. The rate of participation was 84.7%. Using enquete questions of current skin rash against the clinical presence of dermatitis, we found a sensitivity of 22% and a specificity of 89%, compared to 45% and 87%, respectively, when the anamnestic work history, taken by an occupational physician, was the screening parameter. Using 'workplace periodic prevalence' of dermatitis, we found sensitivities in the range of 63-76% by a questionnaire and 70-83% by medical anamnesis. Questionnaire screening by skin symptoms gave the highest values for redness, a sensitivity of 33% and a specificity of 76%, and decreasing validity parameters as more symptoms were added to the list of screening questions. We found that the use of a questionnaire and medical anamnesis were problematic, when the purpose was screening for contact dermatitis and allergy, in this industrial cohort manufacturing reinforced plastic products. But these instruments might be useful for epidemiological surveillance, when the questionnaire has been validated in the given occupational setting.
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| 4. |
- Holmberg, Anna, et al.
(författare)
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Biofilm formation by Propionibacterium acnes is a characteristic of invasive isolates
- 2009
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Ingår i: Clinical Microbiology and Infection. - : Elsevier BV. - 1198-743X .- 1469-0691. ; 15:8, s. 787-795
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Tidskriftsartikel (refereegranskat)abstract
- Propionibacterium acnes is a common and probably underestimated cause of delayed joint prosthesis infection. Bacterial biofilm formation is central in the pathogenesis of infections related to foreign material, and P. acnes has been shown to form biofilm both in vitro and in vivo. Here, biofilm formation by 93 P. acnes isolates, either from invasive infections (n = 45) or from the skin of healthy people (n = 48), was analysed. The majority of isolates from deep infections produced biofilm in a microtitre model of biofilm formation, whereas the skin isolates were poor biofilm producers (p <0.001 for a difference). This indicates a role for biofilm formation in P. acnes virulence. The type distribution, as determined by sequencing of recA, was similar among isolates isolated from skin and from deep infections, demonstrating that P. acnes isolates with different genetic backgrounds have pathogenic potential. The biofilm formed on plastic and on bone cement was analysed by scanning electron microscopy (EM) and by transmission EM. The biofilm was seen as a 10-mum-thick layer covering the bacteria and was composed of filamentous as well as more amorphous structures. Interestingly, the presence of human plasma in solution or at the plastic surface inhibits biofilm formation, which could explain why P. acnes primarily infect plasma-poor environments of, for example, joint prostheses and cerebrospinal shunts. This work underlines the importance of biofilm formation in P. acnes pathogenesis, and shows that biofilm formation should be considered in the diagnosis and treatment of invasive P. acnes infections.
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| 5. |
- Lood, Rolf, et al.
(författare)
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Inducible Siphoviruses in superficial and deep tissue isolates of Propionibacterium acnes
- 2008
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Ingår i: BMC Microbiology. - : Springer Science and Business Media LLC. - 1471-2180. ; 8
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Tidskriftsartikel (refereegranskat)abstract
- Background: Propionibacterium acnes is a commensal of human skin but is also known to be involved in certain diseases, such as acne vulgaris and infections of orthopaedic implants. Treatment of these conditions is complicated by increased resistance to antibiotics and/or biofilm formation of P. acnes bacteria. P. acnes can be infected by bacteriophages, but until recently little has been known about these viruses. The aim of this study was to identify and characterize inducible phages from P. acnes on a genetic and morphological basis. Results: More than 70% (65/92) of P. acnes isolates investigated have inducible phages, classified morphologically as Siphoviruses. The phages have a head of 55 nm in diameter and a tail of 145 155 nm in length and 9-10 nm in width. There was no difference in carriage rate of phages between P. acnes isolates from deep infections and isolates from skin. However, there was a significant lower carriage rate of phages in P. acnes biotype IB, mostly attributed to the low carriage rate of inducible phages in biotype IB isolated from deep tissue. Most phages have a strong lytic activity against all P. acnes isolates with inducible phages, but have less lytic activity against isolates that have no prophages. Phages only infected and lysed P. acnes and not other closely related propionibacteria. All phages could infect and lyse their non-induced parental host, indicating that these prophages do not confer superinfection immunity. The phages have identical protein pattern as observed on SDS-PAGE. Finally, sequencing of two phage genes encoding a putative major head protein and an amidase and showed that the phages could be divided into different groups on a genetic basis. Conclusion: Our findings indicate that temperate phages are common in P. acnes, and that they are a genetically and functionally homogeneous group of Siphoviruses. The phages are specific for P. acnes and do not seem to confer superinfection immunity.
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| 6. |
- Rasmussen, K, et al.
(författare)
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Risk of contact allergy and dermatitis at a wind turbine plant using epoxy resin-based plastics
- 2005
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Ingår i: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 1432-1246 .- 0340-0131. ; 78:3, s. 211-217
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Tidskriftsartikel (refereegranskat)abstract
- Aims: To identify workplace and individual risk factors for occupational contact allergy and dermatitis. Methods: A cross-sectional study was carried out at an international company producing wind turbine systems in Denmark. A cohort of 724 production workers at four facilities was highly exposed to epoxy resin as well as other chemicals. A screening questionnaire (participation rate 84.7%) was followed by an interview by an occupational physician and a dermatological examination, including patch testing, for a comprehensive list of potential workplace sensitizers. Results: Clinically diagnosed dermatitis was found among 214 workers (35.8%) and contact allergy to materials used in the workplace was found in 66 workers (10.9% of the total population and 20.3% of those who underwent patch testing). Of the 66 workers with a work-related allergy, 40 (60.6%) were allergic to epoxy compounds, 25 (37.9%) to hardeners and ten (15.2%) to other workplace materials, where one person showed an allergy only to these materials. Experiencing contact allergy was related to older age and longer employment in the workplace-however, neither of these risk factors was significant. The main risk factor for current dermatitis was contact allergy to materials used in the workplace, determined by patch testing, OR=5.4 (95% CI 3.9-9.9). Fewer days of absence from work was also related to current dermatitis, OR=2.0 (95% CI 1.2-3.5). Conclusions: In a cohort of workers with extensive exposure to chemicals related to epoxy-resin systems, contact dermatitis and allergy was prevalent. Older age and longer duration of employment at the workplace were individual risk factors for allergy to workplace materials, whilst work-related allergies and longer duration of employment at the workplace were significant risk factors for current dermatitis.
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