| 1. |
- Ademuyiwa, Adesoji O., et al.
(author)
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Determinants of morbidity and mortality following emergency abdominal surgery in children in low-income and middle-income countries
- 2016
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In: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Journal article (peer-reviewed)abstract
- Background: Child health is a key priority on the global health agenda, yet the provision of essential and emergency surgery in children is patchy in resource-poor regions. This study was aimed to determine the mortality risk for emergency abdominal paediatric surgery in low-income countries globally.Methods: Multicentre, international, prospective, cohort study. Self-selected surgical units performing emergency abdominal surgery submitted prespecified data for consecutive children aged <16 years during a 2-week period between July and December 2014. The United Nation's Human Development Index (HDI) was used to stratify countries. The main outcome measure was 30-day postoperative mortality, analysed by multilevel logistic regression.Results: This study included 1409 patients from 253 centres in 43 countries; 282 children were under 2 years of age. Among them, 265 (18.8%) were from low-HDI, 450 (31.9%) from middle-HDI and 694 (49.3%) from high-HDI countries. The most common operations performed were appendectomy, small bowel resection, pyloromyotomy and correction of intussusception. After adjustment for patient and hospital risk factors, child mortality at 30 days was significantly higher in low-HDI (adjusted OR 7.14 (95% CI 2.52 to 20.23), p<0.001) and middle-HDI (4.42 (1.44 to 13.56), p=0.009) countries compared with high-HDI countries, translating to 40 excess deaths per 1000 procedures performed.Conclusions: Adjusted mortality in children following emergency abdominal surgery may be as high as 7 times greater in low-HDI and middle-HDI countries compared with high-HDI countries. Effective provision of emergency essential surgery should be a key priority for global child health agendas.
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| 2. |
- Ahlborg, Liv, et al.
(author)
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Visuospatial ability correlates with performance in simulated gynecological laparoscopy
- 2011
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In: European Journal of Obstetrics, Gynecology, and Reproductive Biology. - : Elsevier BV. - 0301-2115 .- 1872-7654. ; 157:1, s. 73-77
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Journal article (peer-reviewed)abstract
- Objective: To analyze the relationship between visuospatial ability and simulated laparoscopy performed by consultants in obstetrics and gynecology (OBGYN). Study design: This was a prospective cohort study carried out at two community hospitals in Sweden. Thirteen consultants in obstetrics and gynecology were included. They had previously independently performed 10-100 advanced laparoscopies. Participants were tested for visuospatial ability by the Mental Rotations Test version A (MRT-A). After a familiarization session and standardized instruction, all participants subsequently conducted three consecutive virtual tubal occlusions followed by three virtual salpingectomies. Performance in the simulator was measured by Total Time, Score and Ovarian Diathermy Damage. Linear regression was used to analyze the relationship between visuospatial ability and simulated laparoscopic performance. The learning curves in the simulator were assessed in order to interpret the relationship with the visuospatial ability. Results: Visuospatial ability correlated with Total Time (r = -0.62; p = 0.03) and Score (r = 0.57; p = 0.05) in the medium level of the virtual tubal occlusion. In the technically more advanced virtual salpingectomy the visuospatial ability correlated with Total Time (r = -0.64; p = 0.02), Ovarian Diathermy Damage (r = -0.65; p = 0.02) and with overall Score (r = 0.64; p = 0.02). Conclusions: Visuospatial ability appears to be related to the performance of gynecological laparoscopic procedures in a simulator. Testing visuospatial ability might be helpful when designing individual training programs.
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| 3. |
- Andersson, Pehr, et al.
(author)
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Working memory and virtual endoscopy simulation
- 2004
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In: Proceedings of the twenty-sixth annual conference of the cognitive science society. - Mahwah : Lawrence Erlbaum Associates. - 9780805854640 ; , s. 1519-1519
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Conference paper (peer-reviewed)
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| 4. |
- Arvidsson, Anna, 1973, et al.
(author)
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Formation of calcium phosphates on titanium implants with four different bioactive surface preparations. An in vitro study
- 2007
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In: Journal of Materials Science-Materials in Medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 18:10, s. 1945-1954
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Journal article (peer-reviewed)abstract
- The aim of the present study was to compare the nucleating and growing behaviour on four types of bioactive surfaces by using the simulated body fluid (SBF) model. Titanium discs were blasted and then prepared by alkali and heat treatment, anodic oxidation, fluoridation, or hydroxyapatite coating. The discs were immersed in SBF for 1, 2, 4 and 6 weeks. Calcium phosphates were found on all specimens, as analysed with scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX). After 1 and 2 weeks of SBF immersion more titanium was accessible with SEM/EDX on the blasted surfaces than the four bioactive surface types, indicating a difference in coverage by calcium phosphates. The Ca/P mean ratio of the surfaces was approximately 1.5 after 1 week, in contrast to the fluoridated specimens which displayed a Ca/P mean ratio of approximately 2. Powder X-ray diffraction (P-XRD) analyses showed the presence of hydroxyapatite on all types of surfaces after 4 and 6 weeks of immersion. The samples immersed for 6 weeks showed a higher degree of crystallinity than the samples immersed for 4 weeks. In conclusion, differences appeared at the early SBF immersion times of 1 and 2 weeks between controls and bioactive surface types, as well as between different bioactive surface types.
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| 5. |
- Barkarmo, Sargon, et al.
(author)
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Nano-hydroxyapatite-coated PEEK implants : a pilot study in rabbit bone
- 2013
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In: Journal of Biomedical Materials Research. Part A. - : John Wiley & Sons. - 1549-3296 .- 1552-4965. ; 101A:2, s. 465-471
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Journal article (peer-reviewed)abstract
- Osseointegration of surface-modified polyetheretherketone (PEEK) implants was studied in vivo. A total of 18 cylinder-shaped PEEK implants were inserted in the femurs of nine New Zealand rabbits; half were coated with nanocrystalline hydroxyapatite (nanoHA) and half were uncoated controls. Healing time was 6 weeks. Samples were retrieved with the implant and surrounding tissue, processed to cut and ground sections, and analyzed histomorphometrically. The implant surfaces were analyzed with optical interferometry, scanning electron microscopy (SEM), atomic force microscopy, and X-ray photoelectron spectroscopy (XPS). NanoHA-coated PEEK surfaces had lower height deviation (Sa) than controls [mean ± SD: 0.41 μm (± 0.14) vs. 0.96 μm (± 0.28)]. SEM images showed the nanoHA crystals as a thin layer on the polymer surface. XPS analysis of the coated implants showed a Ca/P ratio of 1.67. Histomorphometry indicated that the nanoHA-coated implants had more bone-to-implant contact [16% (± 4.7) vs. 13% (± 9.3)] and more bone area [52% (± 9.5) vs. 45% (± 11.9)]. We found no difference between smooth nanoHA-coated cylinder-shaped PEEK implants and uncoated controls. However, higher mean bone-to-implant contact indicated better osseointegration in the coated implants than in the uncoated controls. The large number of lost implants was interpreted as a lack of primary stability due to implant design.
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| 6. |
- Escher, Cecilia, et al.
(author)
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All professions can benefit — a mixed-methods study on simulation-based teamwork training for operating room teams
- 2023
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In: Advances in Science and Technology Research Journal. - : BioMed Central (BMC). - 2364-3277 .- 2059-0628. ; 8:1
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Journal article (peer-reviewed)abstract
- Background: Operating rooms have become more technically complex due to new advanced procedures, which has increased demands on teamwork in the operating room. In response, team training has been proposed to improve team performance, workplace culture, and patient safety. We developed and delivered a simulation-based team training course for entire professional surgical teams. This type of intervention has been proposed by researchers but has not been widely published. The aims of this intervention study were to examine participants’ reactions to the course in terms of their motivation for the training and their self-efficacy in relation to their performance, as well as their views on transferring the lessons learned in the course to their workplace.Methods: In a prospective mixed-methods intervention study, operating room professionals participated in a full-day simulation-based teamwork training course. Learning objectives were nontechnical skills, specifically communication and collaboration across the team. Seventy-one staff members representing 5 operating room professions were included, and the average work experience of participants was 6 years. Quantitative data on self-efficacy and situational motivation were collected by questionnaires before and after training. Qualitative data were collected through 5 focus group interviews that took place in direct relation to the courses and included a total of 31 participants. Transcripts were coded and analyzed using thematic analysis.Results: All occupations showed a similar pattern in terms of increases in self-efficacy and intrinsic motivation after the training. Analysis of the qualitative data showed that training in one’s profession and in authentic multiprofessional teams was important factors for motivation. Participating staff described an awareness of undesirable communication barriers in surgical teams that can lead to risks for patients. Systematic training was definitely perceived as a means to reduce barriers and improve communication and collaboration.Conclusion: Simulation-based training was equally well received by all professional groups. Our results confirm the feasibility of this type of training for professional teams and promising opportunities for improving teamwork skills. The qualitative data reveal both opportunities and limitations for transferring the learning experiences to the workplace.
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| 7. |
- Escher, Cecilia, et al.
(author)
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Medical students' situational motivation to participate in simulation based team training is predicted by attitudes to patient safety
- 2017
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In: BMC Medical Education. - : BIOMED CENTRAL LTD. - 1472-6920. ; 17
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Journal article (peer-reviewed)abstract
- Background: Patient safety education, as well as the safety climate at clinical rotations, has an impact on students' attitudes. We explored medical students' self-reported motivation to participate in simulation-based teamwork training (SBTT), with the hypothesis that high scores in patient safety attitudes would promote motivation to SBTT and that intrinsic motivation would increase after training.Methods: In a prospective cohort study we explored Swedish medical students' attitudes to patient safety, their motivation to participate in SBTT and how motivation was affected by the training. The setting was an integrated SBTT course during the surgical semester that focused on non-technical skills and safe treatment of surgical emergencies. Data was collected using the Situational Motivation Scale (SIMS) and the Attitudes to Patient Safety Questionnaire (APSQ).Results: We found a positive correlation between students' individual patient safety attitudes and self-reported motivation (identified regulation) to participate in SBTT. We also found that intrinsic motivation increased after training. Female students in our study scored higher than males regarding some of the APSQ sub-scores and the entire group scored higher or on par with comparable international samples.Conclusion: In order to enable safe practice and professionalism in healthcare, students' engagement in patient safety education is important. Our finding that students' patient safety attitudes show a positive correlation to motivation and that intrinsic motivation increases after training underpins patient safety climate and integrated teaching of patient safety issues at medical schools in order to help students develop the knowledge, skills and attitudes required for safe practice.
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| 8. |
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| 9. |
- Franke Stenport, Victoria, 1970, et al.
(author)
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Precipitation of calcium phosphate in the presence of albumin on titanium implants with four different possibly bioactive surface preparations. An in vitro study
- 2008
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In: Journal of Materials Science: Materials in Medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 19:12, s. 3497-3505
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Journal article (peer-reviewed)abstract
- The aim of the present study was to compare the nucleating behaviour on four types of bioactive surfaces by using the simulated body fluid (SBF) model with the presence albumin. Titanium discs were blasted (B) and then prepared by alkali and heat treatment (AH), anodic oxidation (AO), fluoridation (F), or hydroxyapatite coating (HA). The discs were immersed in SBF with 4.5 mg/ml albumin for 3 days, 1, 2, 3 and 4 weeks and analysed with scanning electron microscopy/energy dispersive X-ray analysis (SEM/EDX) and X-ray photoelectron spectroscopy (XPS). Topographic surface characterisation was performed with a contact stylus profilometer. The results demonstrated that the bioactive surfaces initiated an enhanced calcium phosphate (CaP) formation and a more rapid increase of protein content was present on the bioactive surfaces compared to the blasted control surface. The observation was present on all bioactive surfaces. The fact that there was a difference between the bioactive surfaces and the blasted control surface with respect to precipitation of CaP and protein content on the surfaces support the fact that there may be biochemical advantages in vivo by using a bioactive surface.
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| 10. |
- Göransson, Anna, 1970, et al.
(author)
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An in vitro comparison of possibly bioactive titanium implant surfaces.
- 2009
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In: Journal of Biomedical Materials Research Part A. - : Wiley. - 1552-4965 .- 1549-3296. ; 88:4, s. 1037-1047
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Journal article (peer-reviewed)abstract
- The aim of the study was to compare Ca and P formation (CaP) and subsequent bone cell response of a blasted and four different possibly bioactive commercially pure (cp) titanium surfaces; 1. Fluoride etched (Fluoride), 2. Alkali-heat treated (AH), 3. Magnesium ion incorporated anodized (TiMgO), and 4. Nano HA coated and heat treated (nano HA) in vitro. Furthermore, to evaluate the significance of the SBF formed CaP coat on bone cell response. The surfaces were characterized by Optical Interferometry, Scanning Electron Microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS). CaP formation was evaluated after 12, 24 and 72 h in simulated body fluid (SBF). Primary human mandibular osteoblast-like cells were cultured on the various surfaces subjected to SBF for 72 h. Cellular attachment, differentiation (osteocalcin) and protein production (TGF-beta(1)) was evaluated after 3 h and 10 days respectively. Despite different morphological appearances, the roughness of the differently modified surfaces was similar. The possibly bioactive surfaces gave rise to an earlier CaP formation than the blasted surface, however, after 72 h the blasted surface demonstrated increased CaP formation compared to the possibly bioactive surfaces. Subsequent bone cell attachment was correlated to neither surface roughness nor the amount of formed CaP after SBF treatment. In contrast, osteocalcin and TGF-beta(1) production were largely correlated to the amount of CaP formed on the surfaces. However, bone response (cell attachment, osteocalcin and TGF-F production) on the blasted controls were similar or increased compared to the SBF treated fluoridated, AH and TiMgO surface. (c) 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2008.
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| 11. |
- Johansson, Pär, et al.
(author)
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Biomechanical evaluation and surface characterization of a nano-modified surface on PEEK implants : a study in the rabbit tibia
- 2014
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In: International Journal of Nanomedicine. - : Nakladatelstvi Lidove noviny. - 1176-9114 .- 1178-2013. ; 9, s. 3903-3911
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Journal article (peer-reviewed)abstract
- Polyether ether ketone (PEEK) is today frequently used as a biomaterial in different medical operations due to its excellent mechanical and chemical properties. However, the untreated surface of PEEK is bio-inert, hydrophobic and does not osseointegrate in its pure form. The aim of this study was to evaluate a unique nano modified surface of PEEK with respect to osseointegration. Forty-eight threaded, non-cutting PEEK implants were inserted bilaterally in the tibia of 24 rabbits. Half of the implants (n = 24) were coated with nanocrystalline hydroxyapatite (test) and the remaining implants (n = 24) were left uncoated (control). Half of the animals (n = 12) were euthanized after 3 weeks of healing and the remaining (n = 12) after 12 weeks. The implant retention was measured with a removal torque apparatus. Surface analysis was performed with interferometry, scanning electron microscopy and X-ray photon spectroscopy to relate the removal torque to the applied surface. The test implants revealed a significantly higher retention after 3 weeks (p-value = 0.05) and 12 weeks (p-value = 0.028) compared to controls. The result of the present study proves that the addition of nanocrystalline HA coating to PEEK surfaces significantly increased its removal torque and biocompability.
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| 12. |
- Johansson, Pär, et al.
(author)
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Biomechanical, histological, and computed X-ray tomographic analyses of hydroxyapatite coated PEEK implants in an extended healing model in rabbit
- 2018
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In: Journal of Biomedical Materials Research Part A. - : Wiley. - 1549-3296 .- 1552-4965. ; 106:5, s. 1440-1447
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Journal article (peer-reviewed)abstract
- A nanosized hydroxyapatite (HA) modification on polyetheretherketone (PEEK) using a novel spin coating technique was investigated in a rabbit model. Spin coating technique creates a 20-40 nm thick layer of nanosized HA particles with similar shape, size, and crystallinity as human bone. Some implants were designed with a perforating hole in the apical region to mimic a fusion chamber of a spinal implant. The coating nano-structures were assessed using a scanning electron microscope. The in vivo response to HA-PEEK was compared to untreated PEEK with respect to removal torque, histomorphometry, and computed microtomography. The HA-coated and pure PEEK implants were inserted in the tibia and femur bone according to simple randomization. The rabbits were sacrificed 20 weeks after implantation. Removal torque analysis showed significantly higher values for HA-PEEK. Qualitative histological evaluation revealed an intimate contact between PEEK and the bone at the threads and perforated hole. Histomorphometric assessment showed higher bone-implant and bone area values for HA-PEEK but without statistical significance. The effect of the HA coating showed most prominent effect in the removal torque which may be correlated to an alteration in the bone quality around the HA-PEEK implants. (c) 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 1440-1447, 2018.
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| 13. |
- Johansson, Pär, et al.
(author)
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Nanosized Hydroxyapatite Coating on PEEK Implants Enhances Early Bone Formation : A Histological and Three-Dimensional Investigation in Rabbit Bone
- 2015
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In: Materials. - : MDPI. - 1996-1944. ; 8:7, s. 3815-3830
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Journal article (peer-reviewed)abstract
- Polyether ether ketone (PEEK) has been frequently used in spinal surgery with good clinical results. The material has a low elastic modulus and is radiolucent. However, in oral implantology PEEK has displayed inferior ability to osseointegrate compared to titanium materials. One idea to reinforce PEEK would be to coat it with hydroxyapatite (HA), a ceramic material of good biocompatibility. In the present study we analyzed HA-coated PEEK tibial implants via histology and radiography when following up at 3 and 12 weeks. Of the 48 implants, 24 were HA-coated PEEK screws (test) and another 24 implants served as uncoated PEEK controls. HA-coated PEEK implants were always osseointegrated. The total bone area (BA) was higher for test compared to control implants at 3 (p < 0.05) and 12 weeks (p < 0.05). Mean bone implant contact (BIC) percentage was significantly higher (p = 0.024) for the test compared to control implants at 3 weeks and higher without statistical significance at 12 weeks. The effect of HA-coating was concluded to be significant with respect to early bone formation, and HA-coated PEEK implants may represent a good material to serve as bone anchored clinical devices.
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| 14. |
- Johansson, Pär, et al.
(author)
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Polyether ether ketone implants achieve increased bone fusion when coated with nano-sized hydroxyapatite : a histomorphometric study in rabbit bone
- 2016
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In: International Journal of Nanomedicine. - : Nakladatelstvi Lidove noviny. - 1176-9114 .- 1178-2013. ; 11:11, s. 1435-1442
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Journal article (peer-reviewed)abstract
- Polyether ether ketone (PEEK) possesses excellent mechanical properties similar to those of human bone and is considered the best alternative material other than titanium for orthopedic spine and trauma implants. However, the deficient osteogenic properties and the bioinertness of PEEK limit its fields of application. The aim of this study was to limit these drawbacks by coating the surface of PEEK with nano-scaled hydroxyapatite (HA) minerals. In the study, the biological response to PEEK, with and without HA coating, was investigated. Twenty-four screw-like and apically perforated implants in the rabbit femur were histologically evaluated at 3 weeks and 12 weeks after surgery. Twelve of the 24 implants were HA coated (test), and the remaining 12 served as uncoated PEEK controls. At 3 weeks and 12 weeks, the mean bone–implant contact was higher for test compared to control (P,0.05). The bone area inside the threads was comparable in the two groups, but the perforating hole showed more bone area for the HA-coated implants at both healing points (P,0.01). With these results, we conclude that nano-sized HA coating on PEEK implants significantly improved the osteogenic properties, and in a clinical situation this material composition may serve as an implant where a rapid bone fusion is essential.
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| 15. |
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| 16. |
- Johnson, Ericka, 1973-, et al.
(author)
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Evaluating instruction of medical students with a haptic surgical simulator : The importance of coordinating students' perspectives
- 2004
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In: Journal on Information Technology in Healthcare. - 1479-649X. ; 2:3, s. 155-163
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Journal article (peer-reviewed)abstract
- Objective: To examine the practices surrounding the use of a surgical simulator in training medical students. Design: Non-randomised observational study. Setting: Teaching hospital in Sweden. Methods: Two separate studies were performed using a haptically enabled (i.e. providing tactile feedback) surgical simulator. In the first study a total of 46 students and two instructors were observed as the students trained their speed and accuracy in locating spheres in a simulated abdomen, shoulder and knee. Through qualitative analysis of video of the instructors' teaching, methods for reconstituting medical practice in the simulations were observed. In the second, quantitative, study, a subgroup of 30 students performed two tests on the simulator, the first relying solely on the on-screen instructions available with the simulator and the second after receiving individual instruction from a practising surgeon. The difference between these two scores was analysed and students were asked to evaluate their experience of the simulator and training session. Results: The first study demonstrated what methods the instructors used to help students relate the computer screen image to human anatomy, and to make the training with the simulator clinically relevant and authentic. The instructors did this by actively aligning and coordinating the students' perspectives, and by reconstituting patient bodies into the simulation. In the second study the students' test results were significantly improved after receiving instruction from the surgeon. Conclusion: The results from these two studies demonstrate the important role that instructors play in simulator training. They also suggest practices to consider when designing a programme for simulator training.
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| 17. |
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| 18. |
- Kileng, Hege, et al.
(author)
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Personalized treatment of hepatitis C genotype 1a in Norway and Sweden 2014-2016 : a study of treatment outcome in patients with or without resistance-based DAA-therapy
- 2018
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In: Scandinavian Journal of Gastroenterology. - : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 53:10-11, s. 1347-1353
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Journal article (peer-reviewed)abstract
- OBJECTIVES: Resistance-associated substitutions (RASs) may impair treatment response to direct-acting antivirals (DAA) in hepatitis C virus (HCV) treatment. We investigated the effects of baseline NS3-RASs (Q80K and R155K) and clinically relevant NS5A-RASs in patients with HCV genotype (GT) 1a infection on treatment outcome, with or without resistance-based DAA-treatment. This multi-center study was carried out between 2014 and 2016.PATIENTS/METHODS: Treatment in the intervention group (n = 92) was tailored to baseline resistance. Detection of NS3-RAS led to an NS5A-inhibitor-based regimen and detection of NS5A-RAS to a protease-inhibitor regimen. Patients without baseline RAS in the intervention group and all patients in the control group (n = 101) received recommended standard DAA-treatment.RESULTS: The sustained virologic response rates (SVR) in the intervention and control groups were 97.8% (90/92) and 93.1% (94/101), respectively (p = .174). A trend toward higher SVR-rate in cirrhotic patients (p = .058) was noticed in the intervention group compared to the control group with SVR-rates 97.5% (39/40) and 83.3% (35/42), respectively. All patients with baseline NS3 (Q80K/R155K) or NS5A-RASs in the intervention group achieved SVR with personalized resistance-based treatment. In the control group, five patients with Q80K or R155K at baseline were treated with simeprevir + sofosbuvir and treatment failed in two of them. Furthermore, one of three patients who failed ledipasvir + sofosbuvir treatment had NS5A-RASs at baseline.CONCLUSIONS: In line with the findings of the OPTIMIST-2 trial for Q80K and the EASL-guidelines 2016 for NS5A-RASs, baseline RASs appeared to have an impact on treatment outcome albeit a statistical significance was not observed in this low-prevalence population.
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| 19. |
- Kjellin, Ann
(author)
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Foregut motility disorders : a clinical and experimental study
- 2004
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Doctoral thesis (other academic/artistic)abstract
- Objective: To investigate some clinical aspects and treatment modalities of foregut motility disorders and to experimentally explore some mechanisms involved. Special emphasis has been put on elucidating and evaluating different treatment modalities. The experimental study investigated the possible role for nitric oxide (NO) in foregut motility disorders. Methods: One randomized study explored the possible role for weight reduction treatment on gastroesophageal reflux (GERD) in obese patients. Two other studies examined surgical treatment of achalasia with special attention to the effect on primary symptoms and side effects such as GERD. Furthermore, the risk for reflux esophagitis or other alterations in histology from distal esophageal mucosa was investigated in a retrospective study of patients with achalasia. The outcome after surgical treatment in other spastic esophageal motility disorders was examined during a long-term follow-up study. In an experimental study, nitric oxide synthase knockout mice (nNOS-/-) were compared with wild type mice, and endothelial synthase knockout mice (eNOS-/-) and the role for NO was investigated in relation to gastric emptying. Results: Despite a significant weight reduction, there was no improvement either in GERD symptoms or objective measurements. Laparoscopic myotomy showed good results after the learning curve but with a risk for reflux even though not always symptomatic. Open myotomy showed excellent improvement in the symptoms of dysphagia in the majority of patients, but there was a risk of reflux and related complications. Additional surgery with a total fundoplication had good effects on dysphagia without reflux side effects. Histological changes in the mucosa of the distal esophagus were apparent primarily in achalasia patients formerly treated with surgery or balloon dilatation. The nNOS-/- mice had significantly delayed gastric emptying for solids and liquids, a greater stomach volume and weight, and hypertrophy of the antral circular muscular layer, compared to both wild type mice and eNOS-/- mice. Conclusions: The most common foregut motility disorder, GERD, does not improve after weight reduction in obese patients. The recommended treatment should be medical or surgical. A clinical investigation in foregut motility disorders showed that surgical treatment in achalasia and other spastic esophageal motility disorders improved symptom in the majority of patients. In achalasia, there is a risk for GERD if the myotomy is not combined with an antireflux procedure. This is evident also in histological investigations in patients with achalasia formerly treated with myotomy. The origin of these foregut motility disorders may partly be related to an imbalance in smooth muscle relaxation due to inadequate neurotransmission of NO.
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| 20. |
- Kjellin, Midori, et al.
(author)
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Effect of the baseline Y93H resistance-associated substitution in HCV genotype 3 for direct-acting antiviral treatment : real-life experience from a multicenter study in Sweden and Norway
- 2019
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In: Scandinavian Journal of Gastroenterology. - : Taylor & Francis. - 0036-5521 .- 1502-7708. ; 54:8, s. 1042-1050
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Journal article (peer-reviewed)abstract
- Background: The NS5A resistance-associated substitution (RAS) Y93H is found quite frequently (5-10%) at baseline in direct-acting antiviral agents (DAA) treatment-naive genotype (GT) 3a patients when studied by the population-sequencing method (cut-off 20%). This RAS may impair HCV DAA treatment response, since it possesses a high fold in vitro resistance to daclatasvir (DCV) and velpatasvir (VEL) in GT 3. We investigated the effect of baseline Y93H in patients with GT 3a infection on treatment outcome, with or without resistance-based DAA-treatment during 2014-2017.Patients/Methods: Treatment in the intervention group (n = 130) was tailored to baseline resistance-findings by population-sequencing method. Detection of baseline Y93H above 20% prompted a prolonged treatment duration of NS5A-inhibitor and sofosbuvir (SOF) and/or addition of ribavirin (RBV). Patients without baseline Y93H in the intervention group and all patients in the control group (n = 78) received recommended standard DAA-treatment.Results: A higher sustained virologic response rate (SVR) in the intervention group was shown compared to the control group at 95.4% (124/130) and 88.5% (69/78), respectively (p = .06). All five patients with baseline Y93H in the intervention group achieved SVR with personalised treatment based on results from resistance testing; either with the addition of RBV or prolonged treatment duration (24w). In the control group, 2/4 patients with Y93H at baseline treated with ledipasvir/SOF/RBV or DCV/SOF without RBV, failed treatment.Conclusion: The results from this real-life study are in accordance with the findings of the randomised controlled trials in 2015 and the EASL-guidelines of 2016, thus, baseline Y93H impacts on DCV and VEL treatment outcome.
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| 21. |
- Kjellin, P., et al.
(author)
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A nanosized zirconium phosphate coating for PEEK implants and its effect in vivo
- 2020
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In: Materialia. - : Elsevier BV. - 2589-1529. ; 10
-
Journal article (peer-reviewed)abstract
- Surface treatments and coatings can be applied to polyether ether ketone (PEEK) implants to improve their ability to osseointegrate. A new coating, consisting of amorphous nanosized zirconium phosphate (ZrP) was applied to PEEK and titanium substrates. The coating was applied by using a microemulsion as a carrier for the nanoparticles. It was found that the coating formed a thin continuous porous layer on top of the substrate, with pore diameters of 10–50 nm. The thickness of the coating was estimated to <100 nm. The resistance to acidic (pH = 4) conditions and exposure to ultrasonication was investigated with XPS, which showed no loss of coating. The adherence of the coating was investigated by insertion of implants in simulated bone material, which showed a minor loss in coating. In vitro (SBF) testing showed that the coating promoted crystallization of calcium phosphates, for uncoated PEEK, no crystallization was detected. The in vivo performance of the ZrP coating was examined by coating screw shaped PEEK implants which were implanted in rabbit tibia for 6 weeks. The anchoring strength of the implants was evaluated with removal torque (RTQ) measurements. The average RTQ for the ZrP coated implants was significantly higher compared to the non-coated implants. The results show that a nanosized ZrP coating on PEEK implants can transform the surface from having a low ability to osseointegrate to a surface which stimulates bone tissue growth. This makes the ZrP coating an interesting alternative for coating PEEK implants, such as spinal fusion cages and tendon fixation screws. © 2020
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| 22. |
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| 23. |
- Meirelles, Luiz, 1974, et al.
(author)
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Bone reaction to nano hydroxyapatite modified titanium implants placed in a gap-healing model
- 2008
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In: Journal Biomedical MAterials Research - A. - : Wiley. - 1549-3296 .- 1552-4965. ; 87:3, s. 624-631
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Journal article (peer-reviewed)abstract
- Nanohydroxyapatite materials show similar chemistry to the bone apatite and depending on the underlying topography and the method of preparation, the nanohydroxyapatite may simulate the specific arrangement of the crystals in bone. Hydroxyapatite (HA) and other CaP materials have been indicated in cases in which the optimal surgical fit is not achievable during surgery, and the HA surface properties may enhance bone filling of the defect area. In this study, very smooth electropolished titanium implants were used as substrata for nano-HA surface modification and as control. One of each implant (control and nano HA) was placed in the rabbit tibia in a surgical site 0.7 mm wider than the implant diameter, resulting in a gap of 0.35 mm on each implant side. Implant stability was ensured by a fixating plate fastened with two side screws. Topographical evaluation performed with an optical interferometer revealed the absence of microstructures on both implants and higher resolution evaluation with AFM showed similar nanoroughness parameters. Surface pores detected on the AFM measurements had similar diameter, depth, and surface porosity (%). Histological evaluation demonstrated similar bone formation for the nano HA and electropolished implants after 4 weeks of healing. These results do not support that nano-HA chemistry and nanotopography will enhance bone formation when placed in a gap-healing model. The very smooth surface may have prevented optimal activity of the material and future studies may evaluate the synergic effects of the surface chemistry, micro, and nanotopography, establishing the optimal parameters for each of them.
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| 24. |
- Meirelles, Luiz, 1974, et al.
(author)
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Effect of hydroxyapatite and titania nanostructures on early in vivo bone response
- 2008
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In: Clinical Implant Dentistry and Related Research. - : Wiley. - 1708-8208 .- 1523-0899. ; 10:4, s. 245-254
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Journal article (peer-reviewed)abstract
- Objective: Hydroxyapatite or titania nano structures were applied on smooth titanium implant cylinders. The aim was to investigate whether nano HA may result in enhanced osseointegration compared to nano titania structures. Material and Methods: Surface topography evaluation included detailed characterization of nano size structures present at the implant surface combined with surface roughness parameters at the micro- and nano- meter level of resolution. Microstructures were removed from the surface to ensure that bone response observed was dependent only on the nanotopography and/or chemistry of the surface. Early in vivo bone response (4 weeks) evaluation was investigated in a rabbit model. Results: In the present study, nano titania coated implants showed an increased coverage area and feature density, forming a homogenous layer compared to nano HA implants. Bone response observed at 4 weeks could not be explained by the surface chemistry. New formed bone connected to the original cortical bone demonstrated an increase of 24% for the nano titania compared to the nano HA implant, although the difference was not statistically significant. Conclusion: Thus, no evidence of enhanced bone formation to nano hydroxyapatite modified implants was observed compared to nano titania modified implants. The presence of specific nano structures; dependent on the surface modification exhibiting different size and distribution did modulate in vivo bone response.
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| 25. |
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