| 1. |
- Ademuyiwa, Adesoji O., et al.
(författare)
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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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Ingår i: BMJ Global Health. - : BMJ Publishing Group Ltd. - 2059-7908. ; 1:4
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Tidskriftsartikel (refereegranskat)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. |
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| 3. |
- Candefjord, Stefan, et al.
(författare)
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Combining fibre optic Raman spectroscopy and tactile resonance measurement for tissue characterization
- 2010
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Ingår i: Measurement science and technology. - : IOP Publishing Ltd. - 0957-0233 .- 1361-6501. ; 21:125801, s. 1-8
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Tidskriftsartikel (refereegranskat)abstract
- Tissue characterization is fundamental for identification of pathological conditions. Raman spectroscopy (RS) and tactile resonance measurement (TRM) are two promising techniques that measure biochemical content and stiffness, respectively. They have potential to complement the golden standard-–histological analysis. By combining RS and TRM, complementary information about tissue content can be obtained and specific drawbacks can be avoided. The aim of this study was to develop a multivariate approach to compare RS and TRM information. The approach was evaluated on measurements at the same points on porcine abdominal tissue. The measurement points were divided into five groups by multivariate analysis of the RS data. A regression analysis was performed and receiver operating characteristic (ROC) curves were used to compare the RS and TRM data. TRM identified one group efficiently (area under ROC curve 0.99). The RS data showed that the proportion of saturated fat was high in this group. The regression analysis showed that stiffness was mainly determined by the amount of fat and its composition. We concluded that RS provided additional, important information for tissue identification that was not provided by TRM alone. The results are promising for development of a method combining RS and TRM for intraoperative tissue characterization.
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| 4. |
- Candefjord, Stefan, et al.
(författare)
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Combining scanning haptic microscopy and fibre optic Raman spectroscopy for tissue characterization
- 2012
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Ingår i: Journal of Medical Engineering & Technology. - : Taylor & Francis. - 0309-1902 .- 1464-522X. ; 36:6, s. 319-327
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Tidskriftsartikel (refereegranskat)abstract
- The tactile resonance method (TRM) and Raman spectroscopy (RS) are promising for tissue characterization in vivo. Our goal is to combine these techniques into one instrument, to use TRM for swift scanning, and RS for increasing the diagnostic power. The aim of this study was to determine the classification accuracy, using support vector machines, for measurements on porcine tissue and also produce preliminary data on human prostate tissue. This was done by developing a new experimental set-up combining micro-scale TRMscanning haptic microscopy (SHM)for assessing stiffness on a micro-scale, with fibre optic RS measurements for assessing biochemical content. We compared the accuracy using SHM alone versus SHM combined with RS, for different degrees of tissue homogeneity. The cross-validation classification accuracy for healthy porcine tissue types using SHM alone was 6581%, and when RS was added it increased to 8187%. The accuracy for healthy and cancerous human tissue was 6770% when only SHM was used, and increased to 7277% for the combined measurements. This shows that the potential for swift and accurate classification of healthy and cancerous prostate tissue is high. This is promising for developing a tool for probing the surgical margins during prostate cancer surgery.
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| 5. |
- Candefjord, Stefan, et al.
(författare)
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Evaluating the use of a Raman fiberoptic probe in conjunction with a resonance sensor for measuring porcine tissue in vitro
- 2009
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Ingår i: IFMBE Proceedings of the World Congress on Medical Physics and Biomedical Engineering. - Heidelberg : Springer. ; , s. 414-417, s. 414-417
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Konferensbidrag (refereegranskat)abstract
- Prostate cancer is the most common form of cancer and is the third leading cause of cancer-related death in European men. There is a need for new methods that can accurately localize and diagnose prostate cancer. In this study a new approach is presented: a combination of resonance sensor technology and Raman spectroscopy. Both methods have shown promising results for prostate cancer detection in vitro. The aim of this study was to evaluate the combined information from measurements with a Raman fiberoptic probe and a resonance sensor system. Pork belly tissue was used as a model system. A three-dimensional translation table was equipped with an in-house developed software, allowing measurements to be performed at the same point using two separate instruments. The Raman data was analyzed using principal component analysis and hierarchical clustering analysis. The spectra were divided into 5 distinct groups. The mean stiffness of each group was calculated from the resonance sensor measurements. One of the groups differed significantly (p < 0.05) from the others. A regression analysis, with the stiffness parameter as response variable and the principal component scores of the Raman data as the predictor variables, explained 67% of the total variability. The use of a smaller resonance sensor tip would probably increase the degree of correlation. In conclusion, Raman spectroscopy provides additional discriminatory power to the resonance sensor.
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| 6. |
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| 7. |
- Kahn, Nicolas, et al.
(författare)
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Early Career Members at the ERS International Congress 2017 : highlights from the Assemblies.
- 2017
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Ingår i: Breathe. - : European Respiratory Society (ERS). - 1810-6838 .- 2073-4735. ; 13:4, s. e121-e129
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Tidskriftsartikel (refereegranskat)abstract
- The 2017 ERS International Congress was, as always, well organised, providing participants with a good mixture of translational and clinical science. Early career members were very well represented in thematic poster, poster discussion and oral presentation sessions and were also actively involved in chairing sessions. The efforts of the Early Career Members Committee (ECMC) to increase the number of early career members included in the competence list (the list of early career members with an interest in being more actively involved in the society) paid off immensely, because the number of early career members registered improved hugely across all assemblies after the Congress. Several newly registered early career members have collated some highlights of the Congress for their assemblies, which should be of interest to all members. As assemblies 12 and 13 are new, there is no report from assembly 12 as there is not yet, at the time of writing, an early career member representative for this newly created assembly.
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| 8. |
- Lane, Jennifer C E, et al.
(författare)
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Risk of depression, suicide and psychosis with hydroxychloroquine treatment for rheumatoid arthritis: a multinational network cohort study.
- 2021
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Ingår i: Rheumatology (Oxford, England). - : Oxford University Press (OUP). - 1462-0332 .- 1462-0324. ; 60:7, s. 3222-3234
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Tidskriftsartikel (refereegranskat)abstract
- Concern has been raised in the rheumatology community regarding recent regulatory warnings that HCQ used in the coronavirus disease 2019 pandemic could cause acute psychiatric events. We aimed to study whether there is risk of incident depression, suicidal ideation or psychosis associated with HCQ as used for RA.We performed a new-user cohort study using claims and electronic medical records from 10 sources and 3 countries (Germany, UK and USA). RA patients ≥18years of age and initiating HCQ were compared with those initiating SSZ (active comparator) and followed up in the short (30days) and long term (on treatment). Study outcomes included depression, suicide/suicidal ideation and hospitalization for psychosis. Propensity score stratification and calibration using negative control outcomes were used to address confounding. Cox models were fitted to estimate database-specific calibrated hazard ratios (HRs), with estimates pooled where I2<40%.A total of 918144 and 290383 users of HCQ and SSZ, respectively, were included. No consistent risk of psychiatric events was observed with short-term HCQ (compared with SSZ) use, with meta-analytic HRs of 0.96 (95% CI 0.79, 1.16) for depression, 0.94 (95% CI 0.49, 1.77) for suicide/suicidal ideation and 1.03 (95% CI 0.66, 1.60) for psychosis. No consistent long-term risk was seen, with meta-analytic HRs of 0.94 (95% CI 0.71, 1.26) for depression, 0.77 (95% CI 0.56, 1.07) for suicide/suicidal ideation and 0.99 (95% CI 0.72, 1.35) for psychosis.HCQ as used to treat RA does not appear to increase the risk of depression, suicide/suicidal ideation or psychosis compared with SSZ. No effects were seen in the short or long term. Use at a higher dose or for different indications needs further investigation.Registered with EU PAS (reference no. EUPAS34497; http://www.encepp.eu/encepp/viewResource.htm? id=34498). The full study protocol and analysis source code can be found at https://github.com/ohdsi-studies/Covid19EstimationHydroxychloroquine2.
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| 9. |
- Lane, J. C. E., et al.
(författare)
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Risk of hydroxychloroquine alone and in combination with azithromycin in the treatment of rheumatoid arthritis: a multinational, retrospective study
- 2020
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Ingår i: Lancet Rheumatology. - : Elsevier BV. - 2665-9913. ; 2:11
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Tidskriftsartikel (refereegranskat)abstract
- Background Hydroxychloroquine, a drug commonly used in the treatment of rheumatoid arthritis, has received much negative publicity for adverse events associated with its authorisation for emergency use to treat patients with COVID-19 pneumonia. We studied the safety of hydroxychloroquine, alone and in combination with azithromycin, to determine the risk associated with its use in routine care in patients with rheumatoid arthritis. Methods In this multinational, retrospective study, new user cohort studies in patients with rheumatoid arthritis aged 18 years or older and initiating hydroxychloroquine were compared with those initiating sulfasalazine and followed up over 30 days, with 16 severe adverse events studied. Self-controlled case series were done to further establish safety in wider populations, and included all users of hydroxychloroquine regardless of rheumatoid arthritis status or indication. Separately, severe adverse events associated with hydroxychloroquine plus azithromycin (compared with hydroxychloroquine plus amoxicillin) were studied. Data comprised 14 sources of claims data or electronic medical records from Germany, Japan, the Netherlands, Spain, the UK, and the USA. Propensity score stratification and calibration using negative control outcomes were used to address confounding. Cox models were fitted to estimate calibrated hazard ratios (HRs) according to drug use. Estimates were pooled where the I-2 value was less than 0.4. Findings The study included 956 374 users of hydroxychloroquine, 310 350 users of sulfasalazine, 323 122 users of hydroxychloroquine plus azithromycin, and 351 956 users of hydroxychloroquine plus amoxicillin. No excess risk of severe adverse events was identified when 30-day hydroxychloroquine and sulfasalazine use were compared. Selfcontrolled case series confirmed these findings. However, long-term use of hydroxychloroquine appeared to be associated with increased cardiovascular mortality (calibrated HR 1.65 [95% CI 1.12-2.44]). Addition of azithromycin appeared to be associated with an increased risk of 30-day cardiovascular mortality (calibrated HR 2.19 [95% CI 1.22-3.95]), chest pain or angina (1.15 [1.05-1.26]), and heart failure (1.22 [1.02-1.45]). Interpretation Hydroxychloroquine treatment appears to have no increased risk in the short term among patients with rheumatoid arthritis, but in the long term it appears to be associated with excess cardiovascular mortality. The addition of azithromycin increases the risk of heart failure and cardiovascular mortality even in the short term. We call for careful consideration of the benefit-risk trade-off when counselling those on hydroxychloroquine treatment. Copyright (c) 2020 The Author(s). Published by Elsevier Ltd.
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| 10. |
- Lindahl, Olof A., et al.
(författare)
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Prostate cancer detection using a combination of Raman spectroscopy and stiffness sensing
- 2014
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Ingår i: 1st Global Conference on Biomedical Engineering & 9th Asian-Pacific Conference on Medical and Biological Engineering. - New York : Encyclopedia of Global Archaeology/Springer Verlag. - 9783319122625 - 9783319122625 - 9783319122618 ; , s. 267-270
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Konferensbidrag (refereegranskat)abstract
- Prostate cancer (PCa) is the most common cancer form for men in Europe. A sensor system combining Raman spectroscopy and stiffness sensing with a resonance sensor has recently been developed by us for prostate cancer detection. In this study the sensor system has been used for measurements on two slices of fresh human prostate tissue. The stiffness sensor could detect locations slices with significantly different stiffness contrasts (p < 0.05). Raman spectroscopic measurements could be performed with the dual-modality probe for tissue classification. The findings are important for the continued development of a combination probe for prostate cancer detection.
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| 11. |
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| 12. |
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| 13. |
- Nihlén, Ulf, et al.
(författare)
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Specific nasal symptoms and symptom-provoking factors may predict increased risk of developing COPD.
- 2008
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Ingår i: Clinical Physiology and Functional Imaging. - 1475-0961. ; 28, s. 240-250
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Tidskriftsartikel (refereegranskat)abstract
- In a 1992 questionnaire study, we found that certain nasal symptoms and symptom-provoking factors were associated with prevalence of self-reported chronic bronchitis/emphysema (CBE). In this follow-up study, we examined whether any nasal features could predict an increased incidence of self-reported physician's diagnosis of CBE/chronic obstructive pulmonary disease (COPD). In 2000, a survey was performed similar to the one in 1992. Of a paired follow-up group of 4933 participants aged 28-67 years, 4280 (86.8%) returned the questionnaire. Odds ratios (ORs) for cumulative incidence (between 1992 and 2000) of self-reported physician-diagnosed CBE/COPD and asthma, respectively, were calculated by logistic regression with adjustment for age, gender and smoking habits. Reports of thick, yellow nasal discharge and nasal blockage in 1992 predicted incidence of CBE/COPD: OR 2.3 (1.2-4.2) and 1.8 (1.1-2.8) respectively. Moreover, nasal symptoms provoked by exposure to damp/cold air and tobacco smoke predicted CBE/COPD: OR 3.4 (1.9-6.0) and 2.5 (1.4-4.2). Nasal itching and nasal symptoms provoked by exposure to grass pollen and furred animals predicted incidence of asthma. These results suggest that certain nasal symptoms and nasal symptom-provoking exposures, different from those commonly associated with asthma, may predict increased risk of developing CBE/COPD. This supports the possibility of nasal co-morbidity in COPD.
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| 14. |
- Nyberg, Morgan, et al.
(författare)
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A combined tactile and Raman probe for tissue characterization - Design considerations
- 2012
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Ingår i: Measurement Science and Technology. - : IOP Publishing. - 0957-0233 .- 1361-6501. ; 23:6
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Tidskriftsartikel (refereegranskat)abstract
- Histopathology is the golden standard for cancer diagnosis and involves the characterization of tissue components. It is labour intensive and time consuming. We have earlier proposed a combined fibre-optic near-infrared Raman spectroscopy (NIR-RS) and tactile resonance method (TRM) probe for detecting positive surgical margins as a complement to interoperative histopathology. The aims of this study were to investigate the effects of attaching an RS probe inside a cylindrical TRM sensor and to investigate how laser-induced heating of the fibre-optic NIR-RS affected the temperature of the RS probe tip and an encasing TRM sensor. In addition, the possibility to perform fibre-optic NIR-RS in a well-lit environment was investigated. A small amount of rubber latex was preferable for attaching the thin RS probe inside the TRM sensor. The temperature rise of the TRM sensor due to a fibre-optic NIR-RS at 270 mW during 20 s was less than 2 degrees C. Fibre-optic NIR-RS was feasible in a dimmed bright environment using a small light shield and automatic subtraction of a pre-recorded contaminant spectrum. The results are promising for a combined probe for tissue characterization.
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| 15. |
- Nyberg, Morgan, et al.
(författare)
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Cancer detection probe combining Raman and resonance sensor technology : experimental study on temperature dependence and effects of molding
- 2009
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Ingår i: World Congress on Medical Physics and Biomedical Engineering. - Berlin : Springer Science+Business Media B.V.. - 9783642038976 ; , s. 331-334
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Konferensbidrag (refereegranskat)abstract
- Prostate cancer is a major health problem among men in Europe and the USA. Tactile resonance technology and Raman spectroscopy have both shown promising results in vitro, detecting and diagnosing cancer tumors respectively. A new approach, combining the strength of resonance technology and Raman spectroscopy is investigated. This study deals with the effects of molding a Raman fiber optic probe into a cylindrical resonance sensor element (RSE) to achieve a combined probe. Heat induced by the Raman spectroscopy laser might affect temperature dependent properties of the RSE. Also, molding a Raman probe into a RSE will affect its properties. The RSE temperature dependency was investigated using the resonance sensor system Venustron®. The Raman fiber optic probe was simulated by a thin steel pipe which was molded into a single cylindrical RSE. The effects on the frequency characteristics when modifying the RSE were investigated with a network analyzer. Although the resonance frequency of a RSE is temperature dependent, the frequency shift, as used for calculating stiffness, is not noticeably affected by moderate temperature variations. The RSE properties change less by using a small amount of filler material and a small diameter of the Raman probe.
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| 16. |
- Nyberg, Morgan
(författare)
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Dual-modality probe for prostate cancer detection by combining Raman spectroscopy and tactile resonance technology
- 2013
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prostate adenocarcinoma, or prostate cancer (PCa), is the most common type of cancer and the leading cause of cancer-related deaths for men in Sweden and Europe. Radical prostatectomy (RP) is the most common curative treatment for PCa. This is a surgical procedure where the entire prostate is removed. The surgeons strive to minimise postoperative side-effects, and will use nerve-sparing techniques if possible. The final decision on how much tissue to remove around the prostate is taken during surgery. After the prostate is resected it is histopathologically analysed. The risk of PCa recurrence is elevated when cancer cells are found in the surgical margin. Currently, there is no viable method to detect and localise PCa tumours near the resection margin during surgery. The general aim of this thesis was to develop a medical instrument with the ability to detect PCa tumours near the tissue surface.Datasets from the resonance sensor and from the Raman spectroscopy obtained on porcine model tissue were compared. Principal component analysis (PCA) was used to reduce the Raman spectroscopic dataset, and groups of tissue content were formed by a hierarchical cluster analysis (HCA) of the PCA results. The correlation of the two datasets was evaluated by a model using the PCA results for describing the stiffness of the groups.A support vector machine was evaluated as a method to combine the datasets of the two modalities. The method was used for classifying three types of porcine prostate tissues and to discern healthy vs. cancerous human prostate tissue. The cross-validation accuracy for the SVM classification was 87% for the porcine prostate and 77% for the human prostate tissue types for highly homogeneous tissue samples (>83%). Several important aspects regarding design and methods to be used for combining the two modalities into one probe were investigated. The effects of using different amounts of rubber latex for combining a TRM sensor an a fibre optic Raman probe substitute were determined. A description of the heat produced by the laser at the fibre optic tip was established, and the temperature dependence of Δf was investigated. Methods and conditions, e.g. instrument settings and light shields, for performing Raman spectroscopy with ambient light present were investigated.The dual-modality probe prototype was used to perform the first measurements on porcine model tissue. Methods for using the Raman spectroscopic modality of the combined probe with ambient light present were evaluated. The TRM modality could discern tissue with significantly different stiffness. Raman spectroscopy could be performed with ambient fluorescent light present. The first measurements on fresh human prostate tissue using the dual-modality probe were performed. Prostates with different average stiffnesses could be compared by calculating stiffness contrast. The TRM modality could discern tissue with significantly different stiffness contrast (p < 0.05). The background fluorescence in the Raman spectra of fresh human prostate tissue was higher than expected. The high-wavenumber region, 2700 cm−1 to 3200 cm−1, of the Raman spectra could be used to discern tissue characteristics using HCA of the PCA results. In this thesis, methods and design considerations for the development of a dualmodality probe, combining Raman spectroscopy and tactile resonance sensor technology, were identified and evaluated. In addition, methods for how to use the dual-modality probe for tissue classification and for combining of the datasets of the two modalities, were studied. The resonance sensor swiftly evaluates the tissue stiffness, like the palpation with a finger. The Raman spectroscopy would be applied when malignancy is suspected and adds detailed knowledge of the molecular content. This makes the dual-modality probe a promising instrument for use during RP.
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| 17. |
- Nyberg, Morgan, 1971-, et al.
(författare)
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Dual-modality probe intended for prostate cancer detection combining Raman spectroscopy and tactile resonance technology—discrimination of normal human prostate tissues ex vivo
- 2015
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Ingår i: Journal of Medical Engineering & Technology. - : Taylor & Francis. - 0309-1902 .- 1464-522X. ; 39:3, s. 198-207
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Tidskriftsartikel (refereegranskat)abstract
- Prostate cancer is the most common cancer for men in the western world. For the first time, a dual-modality probe, combining Raman spectroscopy and tactile resonance technology, has been used for assessment of fresh human prostate tissue. The study investigates the potential of the dual-modality probe by testing its ability to differentiate prostate tissue types ex vivo. Measurements on four prostates show that the tactile resonance modality was able to discriminate soft epithelial tissue and stiff stroma (p<0.05). The Raman spectra exhibited a strong fluorescent background at the current experimental settings. However, stroma could be discerned from epithelia by integrating the value of the spectral background. Combining both parameters by a stepwise analysis resulted in 100% sensitivity and 91% specificity. Although no cancer tissue was analysed, the results are promising for further development of the instrument and method for discriminating prostate tissues and cancer.
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| 18. |
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| 19. |
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| 20. |
- Nyberg, Morgan, et al.
(författare)
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Kombinationsinstrument för detektering av prostatacancer : effekter vid ingjutning av Ramanprobe i resonanssensor och temperaturberoende
- 2009
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- Kombinationsinstrument för detektering av prostatacancer – effekter vid ingjutning av Ramanprobe i resonanssensor och temperaturberoendeMorgan Nyberg Doktorand Institutionen för systemteknik, Luleå tekniska universitetKerstin Ramser Universitetslektor Institutionen för systemteknik, Luleå tekniska universitetOlof A. Lindahl Professor Institutionen för systemteknik, Luleå tekniska universitetBakgrundProstatacancer är den cancer som orsakar flest dödsfall bland svenska män. Nya metoder för att detektera och lokalisera prostatatumörer behövs eftersom inga pålitliga metoder finns. Vår avsikt var att utveckla ett nytt instrument som kombinerar resonanssensorteknik och Ramanspektroskopi. Det skulle möjliggöra att detektera och diagnostisera tumörer direkt vid patientundersökningar, vilket minskar risken för komplikationer. Båda teknikerna har visat lovande resultat in vitro. Resonanssensorelement (RSE) består av piezoelektriska kristaller. Förändringen i resonansfrekvens (Δf) för RSE när det kommer i kontakt med ett objekt visar objektets styvhet. Avvikande styvhet kan bero på en tumör. Ramanspektroskopi är en optisk metod som ger information om molekylärt innehåll och förändringar, som kan identifiera cancer. Idén är att integrera en endoskopiskt utformad Ramanprobe som innehåller optiska fibrer i ett cylindriskt ihåligt RSE. I denna studie undersöktes hur kombinationsinstrumentet bäst skall utformas för att undvika förlust i känslighet av RSE:t. Resonansfrekvensen för piezoelektriska material är temperaturberoende. Ett kliniskt instrument används i miljöer med varierande temperatur. Här undersöktes hur detta påverkar förmågan att avgöra styvhet.MetodEffekterna på Δf undersöktes då tunna stålrör (Ø 0,8 mm och Ø 1,2 mm) gjöts in i ett rörformat RSE (l = 15 mm, Øy = 5 mm Øi = 2,8 mm) med kautchuk (Wacker Elastosil RT622, Wacker Chemie GmbH, München, Tyskland). Effekten av mängden gjutmassa uppmättes genom att jämföra hel och halv fyllnad. Effekter av temperaturvariation på Δf undersöktes med ett resonanssystem Venustron® (Axiom Co. Ltd., Koriyama Fukushima, Japan). Mätningarna genomfördes på silikonplatta. I ena fallet varierades hela uppställningens temperatur, i det andra varierades silikonplattans temperatur så övrig utrustning hölls rumstempererad.ResultatResonansfrekvensen och signalkvaliteten förändrades minst med tunnaste stålröret samt med minsta mängden gjutmassa. Största skillnaden i Δf uppmättes till 20,7 Hz vid 1,00 mm djup då hela uppställningens temperatur varierades (22,7°C – 28,4°C). Det är i linje med storleken på feluppskattningarna i tidigare undersökningar gjorda med resonanssensorteknik i rumstemperatur.SammanfattningDenna studie visar på att integration av Raman probe i RSE med bibehållen förmåga att avläsa styvhet är möjlig om man väljer en god metod samt att RSE har försumbar temperaturdrift vid måttliga temperaturvariationer.
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| 21. |
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| 22. |
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| 23. |
- Nyberg, Morgan
(författare)
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Prostate cancer sensor : combining Raman spectroscopy and tactile resonance technology
- 2011
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Licentiatavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Prostate cancer (PCa) is the most common cancer type among men in Sweden. The most prevalent curative treatment for PCa is radical prostatectomy (RP), i.e., complete surgical removal of the prostate. Unfortunately, cancer cells are found near the resection surface in 35 % of the RP patients. This indicates an increased risk of PCa reccurence.Our main objective is to develop a novel medical instrument for detecting PCa. The idea is to combine the techniques of Raman spectroscopy (RS) and the tactile resonance method (TRM) into one integrated instrument. The TRM would provide a swift and gentle survey of the region of interest, while the RS adds detailed information of the molecular content where malignancy is suspected. The dual mode instrument could be well suited for detecting and locating tumour cells in the surgical margin during RP. The studies included in this thesis are important steps towards this objective.Paper A investigated how the two data sets from each of the technologies could be compared and combined for tissue characterisation. The data set of RS was a spectrum with peaks characteristic to the sample's molecular content. The TRM output variable was a scalar value related to the sample stiness. The data sets could be compared and combined by applying principal component analysis (PCA) to the RS spectra followed by an hierarchical cluster analysis (HCA). A linear regression analysis showed that the PCs explained 67% of the stiffness variations. HCA was used to classify each RS measurement into groups consisting of similar measurements. The TRM's sensitivity and specificity of classifying these groups were evaluated by ROC curves and the area under the curve (AUC). The harder group could successfully be discriminated from the softer groups (AUC = 0.99).Paper B used support vector machines (SVM) as a method to classify and differentiate porcine and human prostate tissue types using the combined data sets. Prostate tissue is highly inhomogenous, with streaks of small anatomical structures. The analysis was evaluated within areas of three levels of homogenity, to avoid mismatching the measured tissue. The tissue homogenity was evaluated within the RS measurement area and the tissue type was set to the main histological content. Areas in which no single tissue type surpassed the threshold level were excluded from the analysis. The cross-validation accuracy for determining the tissues types within homogenous (main tissue type > 83%) porcine samples was 82% using TRM data alone. It increased to 87% while using the combined data sets of TRM and RS. For discerning healthy and cancerous human prostate tissue, the cross-validation accuracy was 67% and 77% for TRM alone versus TRM and RS combined.Paper C covered a number of design considerations which have to be addressed during the combination of TRM and RS. The effects of attaching an RS probe into a tubular TRM element were investigated. We investigated the temperature increase caused by the laser illumination from the RS and its eect on the TRM measurement parameter Δf. We also investigated if and how RS could be performed under ambient light. A thin RS probe and a small amount of rubber latex was preferable for attaching the RS probe inside the TRM sensor. The temperature rise of the TRM sensor due to a fibreoptic NIR-RS at 270 mWduring 20 s was less than 2ºC. The variation of Δf during a 5ºC temperature change was approximately 20 Hz. This is small compared to previous in vitro TRM studies. Fibre-optic NIR-RS was feasible in a dimmed bright environment using a small light shield and automatic subtraction of a pre-recorded contaminant spectrum. The results of these studies indicate how the hardware and and software could be combined into one integrated probe for prostate cancer detection.
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| 24. |
- Nyholm, Tufve, et al.
(författare)
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Systematisation of spatial uncertainties for comparison between a MR and a CT-based radiotherapy workflow for prostate treatments
- 2009
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Ingår i: Radiation Oncology. - 1748-717X. ; 4:54
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Tidskriftsartikel (refereegranskat)abstract
- Background: In the present work we compared the spatial uncertainties associated with a MR-based workflow for external radiotherapy of prostate cancer to a standard CT-based workflow. The MR-based workflow relies on target definition and patient positioning based on MR imaging. A solution for patient transport between the MR scanner and the treatment units has been developed. For the CT-based workflow, the target is defined on a MR series but then transferred to a CT study through image registration before treatment planning, and a patient positioning using portal imaging and fiducial markers. Methods: An "open bore" 1.5T MRI scanner, Siemens Espree, has been installed in the radiotherapy department in near proximity to a treatment unit to enable patient transport between the two installations, and hence use the MRI for patient positioning. The spatial uncertainty caused by the transport was added to the uncertainty originating from the target definition process, estimated through a review of the scientific literature. The uncertainty in the CT-based workflow was estimated through a literature review.Results: The systematic uncertainties, affecting all treatment fractions, are reduced from 3-4 mm (ISd) with a CT based workflow to 2-3 mm with a MR based workflow. The main contributing factor to this improvement is the exclusion of registration between MR and CT in the planning phase of the treatment.
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| 25. |
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| 26. |
- Schmidt, Boris, et al.
(författare)
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Design, synthesis, and biological activities of four angiotensin IIreceptor ligands with gamma-turn mimetics replacing amino acid residues 3-5
- 1997
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Ingår i: Journal of Medicinal Chemistry. - : American Chemical Society (ACS). - 0022-2623 .- 1520-4804. ; 40, s. 903-919
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Tidskriftsartikel (refereegranskat)abstract
- Disulfide cyclization is a powerful method for reducing the conformational space of a peptide. This in turn may enable the study of its bioactive conformation. Several analogues of angiotensin II (Ang II) containing a disulfide bridge between amino acids 3 and 5 have been reported. Among these the cyclic octapeptides c[Hcy3,5]-Ang II, c[Cys3,5]-Ang II, and c[Pen 3,5]-Ang II showed significant activity at Ang II receptors. We have performed conformational analysis studies using theoretical calculations and 1H-NMR spectroscopy on tripeptide model compounds of these cyclic octapeptides which show that the cyclic moieties of c[Cys3,5]-Ang II and c[Pen3,5]-Ang II preferentially assume an inverse gamma-turn conformation. On the basis of these results, we substituted amino acid residues 3-5 in Ang II with two different gamma-turn mimetics giving four diastereomeric Ang II analogues. Interestingly, two of these are equipotent to Ang II in binding to AT1 receptors. In the contractile test using rabbit aorta rings, one of the analogues is an agonist with full contractile activity approximately equipotent to c[Pen3,5]-Ang II but 300-fold less potent than Ang II. This low potency may suggest that Ang II does not adopt a gamma-turn in the 3-5 region when interacting with the receptor.
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| 27. |
- Thomas, HS, et al.
(författare)
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- 2019
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swepub:Mat__t
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