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| 3. |
- Lindgren, M, et al.
(författare)
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Investigation of boundary conditions for biomimetic HA deposition on titanium oxide surfaces
- 2009
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Ingår i: Journal of materials science. Materials in medicine. - : Springer Science and Business Media LLC. - 0957-4530 .- 1573-4838. ; 20:7, s. 1401-1408
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Tidskriftsartikel (refereegranskat)abstract
- To improve the clinical outcome of metal implants, i.e. earlier loading and reduction of the incidence of revision surgery, better bone bonding ability is wanted. One method to achieve this is to change the surface chemistry to give a surface that facilitates bone bonding in vivo, i.e. a bioactive surface. Crystalline titanium oxide has recently been proven to be bioactive in vitro and is an interesting option to the more common hydroxylapatite (HA) coatings on implants. A materials possible in vitro bioactivity is tested through soaking in simulated body fluid and studies of possible HA formation on the surface. For bioactive materials, the formed HA layer can also be used as a coating. The aim of the current paper is to investigate some boundary conditions for HA formation on crystalline titanium oxide surfaces regarding influence from coating thickness, soaking time and soaking temperature. The influence from soaking time and temperature on the HA growth were investigated on oxidised Ti samples, (24 h at 800°C) resulting in a rutile surface structure. The oxidised samples were tested at three temperatures (4, 37 and 65°C) and four times (1 h, 1 day, 1 week and 4 weeks). The influence from titanium coating thickness on the HA growth was investigated via depositing thin films of crystalline titanium dioxide on Ti plates using a reactive magnetron sputtering process. Four different PVD runs with coating thicknesses between 19 and 74 nm were tested. The soaking temperature had an effect on the HA formation and growth on both rutile surfaces and native oxide on Ti substrates. Higher temperatures lead to easier formation of HA. It was even possible, at 65°C, to grow HA on native titanium oxide from soaking in PBS. The coating quality was better for HA formed at 65°C compared to 37°C. All PVD-coatings showed HA growth after 1 week in PBS at 37°C, thus even very thin coatings of crystalline titanium oxide coatings are bioactive.
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| 4. |
- Stridh, Sara, et al.
(författare)
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Angiotensin converting enzyme inhibition blocks interstitial hyaluronan dissipation in the neonatal rat kidney via hyaluronan synthase 2 and hyaluronidase 1.
- 2011
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Ingår i: Matrix biology : journal of the International Society for Matrix Biology. - : Elsevier BV. - 1569-1802 .- 0945-053X. ; 30:1, s. 62-9
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Tidskriftsartikel (refereegranskat)abstract
- A functional renin-angiotensin system (RAS) is required for normal kidney development. Neonatal inhibition of the RAS in rats results in long-term pathological renal phenotype and causes hyaluronan (HA), which is involved in morphogenesis and inflammation, to accumulate. To elucidate the mechanisms, intrarenal HA content was followed during neonatal completion of nephrogenesis with or without angiotensin converting enzyme inhibition (ACEI) together with mRNA expression of hyaluronan synthases (HAS), hyaluronidases (Hyal), urinary hyaluronidase activity and cortical lymphatic vessels, which facilitate the drainage of HA from the tissue. In 6-8days old control rats cortical HA content was high and reduced by 93% on days 10-21, reaching adult low levels. Medullary HA content was high on days 6-8 and then reduced by 85% to 12-fold above cortical levels at day 21. In neonatally ACEI-treated rats the reduction in HA was abolished. Temporal expression of HAS2 corresponded with the reduction in HA content in the normal kidney. In ACEI-treated animals cortical HAS2 remained twice the expression of controls. Medullary Hyal1 increased in controls but decreased in ACEI-treated animals. Urine hyaluronidase activity decreased with time in control animals while in ACEI-treated animals it was initially 50% lower and did not change over time. Cells expressing the lymphatic endothelial mucoprotein podoplanin in ACEI-treated animals were increased 18-fold compared to controls suggesting compensation. In conclusion, the high renal HA content is rapidly reduced due to reduced HAS2 and increased Hyal1 mRNA expressions. Normal angiotensin II function is crucial for inducing these changes. Due to the extreme water-attracting and pro-inflammatory properties of HA, accumulation in the neonatally ACEI-treated kidneys may partly explain the pathological renal phenotype of the adult kidney, which include reduced urinary concentration ability and tubulointerstitial inflammation.
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| 7. |
- Baruth, Joshua M., et al.
(författare)
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Distal radius fractures and risk of incident neurocognitive disorders in older adults : a retrospective cohort study
- 2022
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Ingår i: Osteoporosis International. - : Springer Science and Business Media LLC. - 0937-941X .- 1433-2965. ; 33:11, s. 2307-2314
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Tidskriftsartikel (refereegranskat)abstract
- Introduction: Distal radius fractures (DRF) are associated with increased risk of subsequent fractures and physical decline in older adults. This study aims to evaluate the risk cognitive decline following DRF and potential for timely screening and intervention. Methods: A cohort of 1046 individuals 50–75 years of age with DRF were identified between 1995 and 2015 (81.5% female; mean age 62.5 [± 7.1] years). A control group (N = 1044) without history of DRF was matched by age, sex, and fracture date (i.e., index). The incidence of neurocognitive disorders (NCD) in relation to DRF/index was determined. Group comparisons were adjusted by age and comorbidity measured by the Elixhauser index. Results: The DRF group had a greater incidence of NCD compared to the control group (11.3% vs. 8.2%) with a 56% greater relative risk (HR = 1.56, 95% Cl: 1.18, 2.07; p = 0.002) after adjusting for age and comorbidity. For every 10-year age increase, the DRF group was over three times more likely to develop a NCD (HR = 3.23, 95% Cl: 2.57, 4.04; p < 0.001). Conclusion: DRF in adults ages 50 to 75 are associated with increased risk of developing neurocognitive disorders. DRF may represent a sentinel opportunity for cognitive screening and early intervention. Summary: Distal radius fractures (DRF) have been associated with greater risk of future fractures and physical decline. This study reports that DRF are also associated with greater risk of developing neurocognitive disorders in older adults. Timely intervention may improve early recognition and long-term outcomes for older adults at risk of cognitive decline.
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| 8. |
- Bergström, Lena, et al.
(författare)
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Effects of offshore wind farms on marine wildlife-a generalized impact assessment
- 2014
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- Marine management plans over the world express high expectations to the development of offshore wind energy. This would obviously contribute to renewable energy production, but potential conflicts with other usages of the marine landscape, as well as conservation interests, are evident. The present study synthesizes the current state of understanding on the effects of offshore wind farms on marine wildlife, in order to identify general versus local conclusions in published studies. The results were translated into a generalized impact assessment for coastal waters in Sweden, which covers a range of salinity conditions from marine to nearly fresh waters. Hence, the conclusions are potentially applicable to marine planning situations in various aquatic ecosystems. The assessment considered impact with respect to temporal and spatial extent of the pressure, effect within each ecosystem component, and level of certainty. Research on the environmental effects of offshore wind farms has gone through a rapid maturation and learning process, with the bulk of knowledge being developed within the past ten years. The studies showed a high level of consensus with respect to the construction phase, indicating that potential impacts on marine life should be carefully considered in marine spatial planning. Potential impacts during the operational phase were more locally variable, and could be either negative or positive depending on biological conditions as well as prevailing management goals. There was paucity in studies on cumulative impacts and long-term effects on the food web, as well as on combined effects with other human activities, such as the fisheries. These aspects remain key open issues for a sustainable marine spatial planning.
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| 9. |
- Gavali, Hamid, et al.
(författare)
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Outcome of Radical Surgical Treatment of Abdominal Aortic Graft and Endograft Infections Comparing Extra-anatomic Bypass with In Situ Reconstruction : A Nationwide Multicentre Study
- 2021
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Ingår i: European Journal of Vascular and Endovascular Surgery. - : Saunders Elsevier. - 1078-5884 .- 1532-2165. ; 62:6, s. 918-926
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Tidskriftsartikel (refereegranskat)abstract
- Objective: Abdominal aortic graft and endograft infection (AGI) is primarily treated by resection of the infected graft and restoration of distal perfusion through extra-anatomic bypass (EAB) or in situ reconstruction/repair (ISR). The aim of this study was to compare these surgical strategies in a nationwide multicentre retrospective cohort study.Methods: The Swedish Vascular Registry (Swedvasc) was used to identify surgically treated abdominal AGIs in Sweden between January 1995 and May 2017. The primary aim was to compare short and long term survival, as well as complications for EAB and ISR.Results: Some 126 radically surgically treated AGI patients were identified – 102 graft infections and 24 endograft infections – treated by EAB: 71 and ISR: 55 (23 neo-aorto-iliac systems, NAISs). No differences in early 30 day (EAB 81.7% vs. ISR 76.4%, p =.46), or long term five year survival (48.2% vs. 49.9%, p =.87) were identified. There was no survival difference comparing NAIS to other ISR strategies. The frequency of recurrent graft infection during follow up was similar: EAB 20.3% vs. ISR 17.0% (p =.56). Survival and re-infection rates of the new conduit did not differ between NAIS and other ISR strategies. Age ≥ 75 years (odds ratio [OR] 4.0, confidence interval [CI] 1.1 – 14.8), coronary artery disease (OR 4.2, CI 1.2 – 15.1) and post-operative circulatory complications (OR 5.2, CI 1.2 – 22.5) were associated with early death. Prolonged antimicrobial therapy (> 3 months) was associated with reduced long term mortality (HR 0.3, CI 0.1 – 0.9).Conclusion: In this nationwide multicentre study comparing outcomes of radically treated AGI, no differences in survival or re-infection rate could be identified comparing EAB and ISR.
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| 10. |
- Gundersen, Per Ole M., et al.
(författare)
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Metabolite Profiling of Ortho-, Meta- and Para-Fluorofentanyl by Hepatocytes and High-Resolution Mass Spectrometry
- 2020
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Ingår i: Journal of Analytical Toxicology. - : Oxford University Press. - 0146-4760 .- 1945-2403. ; 44:2, s. 140-148
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Tidskriftsartikel (refereegranskat)abstract
- New psychoactive substances are emerging on the illegal drug market. Synthetic opioids including fentanyl analogues are of special concern due to their high potency. This indicates the possibility of low drug concentrations in vivo and calls for sensitive analytical methods and identification of the most appropriate analytical targets. In this study the in vitro metabolism of ortho-, meta- and para-fluorofentanyl, three fluorinated derivatives of fentanyl, has been investigated using human hepatocytes and compared to the results from an authentic human urine sample. Based on knowledge on the metabolism of similar fentanyl analogues N-dealkylation and hydroxylation was hypothesized to be the most central pathways. The three fluorofentanyl isomers were incubated with pooled human hepatocytes at 1, 3 and 5 h. Liquid chromatography quadrupole time of flight mass spectrometry operating in data-dependent mode was used to analyse the hepatocyte samples, as well as the hydrolysed and non-hydrolysed authentic urine sample. Data were analysed by a targeted approach with a database of potential metabolites. The major metabolite formed in vitro was the N-dealkylation product norfluorofentanyl. In addition various hydroxylated metabolites, a N-oxide, dihydrodiol metabolites and a hydroxymethoxy metabolite were found. In total, 14 different metabolites were identified for each fluorofentanyl isomer. In the authentic urine sample, three metabolites were detected in addition to the ortho-fluorofentanyl parent compound, with hydroxymethoxy metabolite having the highest abundance followed by norfluorofentanyl and a metabolite hydroxylated on the ethylphenyl ring. This in vitro study showed that the metabolic pattern for ortho-, meta-, and para-fluorofentanyl was close to those previously reported for other fentanyl analogues. We suggest that the hydroxymethoxy metabolite and the metabolite hydroxylated on the ethylphenyl ring should be the metabolites primarily investigated in further studies to determine the most appropriate marker for intake of fluorofentanyl derivatives in urine drug screening for human subjects.
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| 11. |
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| 12. |
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| 13. |
- Hoffmann, M, et al.
(författare)
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Risk talk: rhetorical strategies in consultations on hormone replacement therapy
- 2003
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Ingår i: Health, Risk & Society. - 1369-8575. ; 5, s. 139-154
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Tidskriftsartikel (refereegranskat)abstract
- When analysing risk discussions in medical settings it is important to consider the specific activity type. In this qualitative study 20 first-time consultations by healthy women regarding hormone replacement therapy (HRT) in the menopause the risk discussion is asymmetrical with the doctors dominating. Despite being set up as a specific opportunity for women in the menopause to discuss problems and risks, it comes forth as a decision-making activity in a traditional medical setting. The consultations fulfil to a high extent the demands for informed decision making, but the risk discussions are recontextualised into a cost-benefit discourse with a typical implicit quantitative bias. The doctors use several different rhetorical strategies such as positive introduction of HRT, embedding drawbacks in positive introductions and/or exits thereby diminishing them. The word risk is avoided to a considerable extent and the term 'drawbacks' is used instead. The most obvious strategy is to move from the woman's symptoms to aspects of prevention, thus changing the discussion from the menopause and different strategies to cope with menopausal problems into a medically oriented discussion of pharmacological treatment alternatives. The 'change of life' in these talks is entirely conceptualised within a 'medical model'.
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| 14. |
- Holmgren, Christina M, et al.
(författare)
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Changes in Medication Preceding Out-of-hospital Cardiac Arrest Where Resuscitation Was Attempted
- 2014
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Ingår i: Journal of Cardiovascular Pharmacology. - : Lippincott Williams & Wilkins. - 0160-2446 .- 1533-4023. ; 63:6, s. 497-503
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Tidskriftsartikel (refereegranskat)abstract
- Objective: To describe recent changes in medication preceding out-of-hospital cardiac arrest (OHCA) where resuscitation was attempted. Methods: OHCA victims were identified by the Swedish Cardiac Arrest Register and linked by means of their unique 10-digit personal identification numbers to the Prescribed Drug Register. We identified new claimed prescriptions during a 6-month period before the OHCA compared with those claimed in the period 12 to 18 months before. The 7-digit Anatomical Therapeutical Chemical codes of individual drugs were used. The study period was November 2007-January 2011. Results: OHCA victims with drugs were (1) older than those who did not claim any drugs in any period (70 +/- 16 years vs. 54 +/- 22 years, P < 0.001), (2) more often women (34% vs. 20%, P < 0.001), and (3) had more often a presumed cardiac etiology (67% vs. 54%, P < 0.001). The OHCA victims were less likely to have ventricular tachycardia/ventricular fibrillation as the first recorded ;rhythm (26% vs. 33%, P < 0.001) or to survive 1 month (9% vs. 17%, P < 0.0001). New prescriptions were claimed by 5122 (71%) of 7243 OHCA victims. The most frequently claimed new drugs were paracetamol (acetaminophen) 10.3%, furosemide 7.8%, and omeprazole 7.6%. Of drugs known or supposed to cause QT prolongation, ciprofloxacin was the most frequent (3.4%) altogether; 16% had a new claimed prescription of a drug included in the "qtdrugs.org" lists. Conclusions: Most OHCA victims had new drugs prescribed within 6 months before the event but most often intended for diseases other than cardiac. No claims can be made as to the causality.
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| 15. |
- Holmgren, Christina M, et al.
(författare)
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Out-of-hospital cardiac arrest : Causes according to autopsy and electrocardiography - Analysis of 781 patients with neither hospital care nor prescribed medication during the preceding two years.
- 2020
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Ingår i: Resuscitation. - : Elsevier BV. - 0300-9572 .- 1873-1570. ; 150, s. 65-71
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: There is a knowledge gap regarding aetiology of and potential for predicting out-of-hospital cardiac arrest (OHCA) among individuals who are healthy before the event.AIM: To describe causes of OHCA and the potential for predicting OHCA in apparently healthy patients.METHODS: Patients were recruited from the Swedish Register of Cardiopulmonary Resuscitation from November 2007 to January 2011. Inclusion criteria were: OHCA with attempted CPR but neither dispensed prescription medication nor hospital care two years before the event The register includes the majority of patients suffering OHCA in Sweden where cardiopulmonary resuscitation (CPR) was attempted. Medication status was defined by linkage to the Swedish Prescribed Drug Register. Cause of death was assessed based on autopsy and the Swedish Cause of Death Register. Prediction of OHCA was attempted based on available electrocardiograms (ECG) before the OHCA event.RESULTS: Altogether 781 individuals (16% women) fulfilled the inclusion criteria. Survival to 30 days was 16%. Autopsy rate was 72%. Based on autopsy, 70% had a cardiovascular aetiology and 59% a cardiac aetiology. An ECG recording before the event was found in 23% of cases. The ECG was abnormal in 22% of them.CONCLUSION: Among OHCA victims who appeared to be healthy prior to the event, the cause was cardiovascular in the great majority according to autopsy findings. A minority had a preceding abnormal ECG that could have been helpful in avoiding the event.
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| 16. |
- Jaen Ortega, A. A., et al.
(författare)
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On Understanding the Role of Exoskeleton Robots in Hand Rehabilitation : A Brief Review
- 2022
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Ingår i: Proceedings - 2022 8th International Engineering, Sciences and Technology Conference, IESTEC 2022. - : Institute of Electrical and Electronics Engineers Inc.. - 9781665498432 ; , s. 432-439
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Konferensbidrag (refereegranskat)abstract
- Hand rehabilitation has been widely studied since it affects the life quality and independence of those affected. Hand impairment can be caused by several conditions, among them strokes and other cerebrovascular accidents, affecting the capabilities of those who survive them in performing the activities of daily living (ADL). Rehabilitation seeks to restore the ability of a person to perform these crucial ADL. There is a current trend in using robotic rehabilitation and other industry 4.0 tools since it can provide a safe, intensive, and task-oriented at a relatively low cost, which can be combined with other technologies such as virtual and augmented reality, BCI, haptics, and others. Moreover, it can provide accessibility in the face of current panoramas such as COVID-19. Hand exoskeleton robots are one of the most extended robotic devices for rehabilitation. However, a design adapted to the patient's needs is necessary to achieve their capability fully and succeed in rehabilitation. One of the main challenges is that several considerations and parameters affect these devices' design and the broad approaches that can be followed. This brief review aims to understand and empathize as a source of inspiration during the design process of hand exoskeleton robots for rehabilitation.
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| 17. |
- Jansson, C, et al.
(författare)
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The prevalence of symptoms possibly related to the climacteric in pre- and postmenopausal women in Link÷ping, Sweden
- 2003
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Ingår i: Maturitas. - 0378-5122 .- 1873-4111. ; 45:2, s. 129-135
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Tidskriftsartikel (refereegranskat)abstract
- Background: Some extragenital symptoms have been suggested to be associated with the menopause and thus to be affected by estrogen status. In such case extragenital symptoms may be more frequent in postmenopausal women without hormone replacement therapy (HRT) than in premenopausal women or women using HRT. Objective: To assess if the prevalence of a number of extragenital symptoms is higher in postmenopausal women without than with HRT, or in premenopausal women of the same age. Material and methods: All women aged 53 and 54 years in the community of Link÷ping (n=1760) were sent a validated questionnaire about use of HRT, time since last menstruation and about different extragenital symptoms. Results: 1298 (73.8%) women answered the questionnaire and answers from 1180 (67%) women were possible to analyze. Postmenopausal women woke up significantly more often during night than premenopausal, and those without HRT often due to hot flushes and sweating. Women with HRT reported more muscular pain than the others. We found no other significant difference in prevalence of extragenital symptoms between the three groups of women. Conclusions: Sleeping disorders, arthralgia, xerophthalmia, xerostomia and dry skin are not more prevalent in 53 and 54 years old postmenopausal women without HRT than in women with HRT or in premenopausal women of the same age. It may still be that some of these symptoms are related to estrogen deficiency, but do not develop until some years after menopause. It may also be that women with the most severe symptoms decided to use HRT and thereby decreased symptoms to the same level as in non-users. ⌐ 2003 Elsevier Science Ireland Ltd. All rights reserved.
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| 18. |
- Lidbeck, Cecilia, et al.
(författare)
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The role of visual stimuli on standing posture in children with bilateral cerebral palsy
- 2016
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Ingår i: BMC Neurology. - : BioMed Central. - 1471-2377. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: In children with bilateral cerebral palsy (CP) maintaining a standing position can be difficult. The fundamental motor task of standing independently is achieved by an interaction between the visual, somatosensory, and vestibular systems. In CP, the motor disorders are commonly accompanied by sensory and perceptual disturbances. Our aims were to examine the influence of visual stimuli on standing posture in relation to standing ability. Methods: Three dimensional motion analysis with surface electromyography was recorded to describe body position, body movement, and muscle activity during three standing tasks: in a self-selected position, while blindfolded, and during an attention-demanding task. Participants were twenty-seven typically-developing (TD) children and 36 children with bilateral CP, of which 17 required support for standing (CP-SwS) and 19 stood without support (CP-SwoS). Results: All children with CP stood with a more flexed body position than the TD children, even more pronounced in the children in CP-SwS. While blindfolded, the CP-SwS group further flexed their hips and knees, and increased muscle activity in knee extensors. In contrast, the children in CP-SwoS maintained the same body position but increased calf muscle activity. During the attention-demanding task, the children in CP-SwoS stood with more still head and knee positions and with less muscle activity. Conclusions: Visual input was important for children with CP to maintain a standing position. Without visual input the children who required support dropped into a further crouched position. The somatosensory and vestibular systems alone could not provide enough information about the body position in space without visual cues as a reference frame. In the children who stood without support, an intensified visual stimulus enhanced the ability to maintain a quiet standing position. It may be that impairments in the sensory systems are major contributors to the difficulties to stand erect in children with CP.
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| 19. |
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| 20. |
- Åstrand, Anders, et al.
(författare)
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Contact angle and indentation velocity dependency for a resonance sensor : Evaluation on soft tissue silicone models
- 2013
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Ingår i: Journal of Medical Engineering & Technology. - : Informa Healthcare. - 0309-1902 .- 1464-522X. ; 37:3, s. 185-196
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Tidskriftsartikel (refereegranskat)abstract
- Human tissue stiffness can vary due to different tissue conditions such as cancer tumours. Earlier studies show that stiffness may be detected with a resonance sensor that measures frequency shift and contact force at application. Through the frequency shift and the contact force, a tissue stiffness parameter can be derived. This study evaluated how the probe application angle and indentation velocity affected the results and determined the maximum parameter errors. The evaluation was made on flat silicone discs with specified hardness. The frequency shift, the force and the stiffness parameter all varied with contact angle and indentation velocity. A contact angle of ≤10° was acceptable for reliable measurements. A low indentation velocity was recommended. The maximum errors for the system were <1.1% of the measured values. It was concluded that contact angle and indentation velocity have to be considered in the clinical setting. The angular dependency is especially important in clinical use for studying stiffness of human soft tissue, e.g. in prostate cancer diagnosis.
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| 21. |
- Åstrand, Anders P., et al.
(författare)
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A flexible sensor system using resonance technology for soft tissue stiffness measurements : evaluation on silicone
- 2011
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Ingår i: 15th Nordic Baltic Conference on Biomedical Engineering and Medical Physics. - Berlin : Encyclopedia of Global Archaeology/Springer Verlag. - 9783642216824 ; , s. 21-24
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Konferensbidrag (refereegranskat)abstract
- One of the most common forms of cancer among men in Europe and the United States is prostate cancer. The cancerous tissue is less soft, and has different biomechanical properties compared to healthy tissue. It has been shown that tactile sensors can be used to distinguish this difference. If a piezoelectric sensor is set to oscillate at its resonance frequency through a feed back circuit, a frequency shift is observed when the sensor comes in contact with a surface. This shift can be correlated to the stiffness of the tissue. A flexible instrument has been developed, with which it is possible to scan both flat and spherical bodies and where the sensor can be tilted to have different contact angles. Measurements performed in this study on flat silicone discs of different stiffness showed a relationship between both the frequency shift and the impression depth for the different silicone discs, when a constant force was applied. The results are promising for future studies on silicone with different geometries and finally on prostate tissue to complete the evaluation.
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| 22. |
- Åstrand, Anders P., et al.
(författare)
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A flexible sensor system using resonance technology for soft tissue stiffness measurements : evaluation on silicone
- 2011
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Ingår i: 15TH NORDIC-BALTIC CONFERENCE ON BIOMEDICAL ENGINEERING AND MEDICAL PHYSICS (NBC 2011). - Aalborg : Springer. - 9783642216824 ; , s. 21-24
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Konferensbidrag (refereegranskat)abstract
- One of the most common forms of cancer amongmen in Europe and the United States is prostate cancer. Thecancerous tissue is less soft, and has different biomechanicalproperties compared to healthy tissue. It has been shown thattactile sensors can be used to distinguish this difference. If apiezoelectric sensor is set to oscillate at its resonance frequencythrough a feed back circuit, a frequency shift is observed whenthe sensor comes in contact with a surface. This shift can becorrelated to the stiffness of the tissue. A flexible instrumenthas been developed, with which it is possible to scan both flatand spherical bodies and where the sensor can be tilted to havedifferent contact angles. Measurements performed in thisstudy on flat silicone discs of different stiffness showed arelationship between both the frequency shift and theimpression depth for the different silicone discs, when aconstant force was applied. The results are promising forfuture studies on silicone with different geometries and finallyon prostate tissue to complete the evaluation.
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| 23. |
- Åstrand, Anders P, 1961-
(författare)
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A Tactile Resonance Sensor System for Detection of Prostate Cancer ex vivo : Design and Evaluation on Tissue Models and Human Prostate
- 2014
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Background The most common form of cancer among males in Europe and the USA is prostate cancer, PCa. Surgical removal of the prostate is the most common form of curative treatment. PCa can be suspected by a blood test for a specific prostate antigen, a PSA-test, and a digital rectal examination, DRE where the physician palpates the prostate through the rectum. Stiff nodules that can be detected during the DRE, and elevated levels of PSA are indications for PCa, and a reason for further examination. Biopsies are taken from the prostate by guidance of a transrectal ultrasound. Superficial cancer tumours can indicate that the cancer has spread to other parts of the body. Tactile resonance sensors can be used to detect areas of different stiffness in soft tissue. Healthy prostate tissue is usually of different stiffness compared to tissue with PCa.AimThe general aim of this doctoral thesis was to design and evaluate a flexible tactile resonance sensor system (TRSS) for detection of cancer in soft human tissue, specifically prostate cancer. The ability to detect cancer tumours located under the surface was evaluated through measurements on tissue phantoms such as silicone and biological tissues. Finally measurements on resected whole prostate glands were made for the detection of cancer tumours.Methods The sensor principle was based on an oscillating piezoelectric element that was indented into the soft tissue. The measured parameters were the change in resonance frequency, Δf, and the contact force F during indentation. From these, a specific stiffness parameter was obtained. The overall accuracy of the TRSS was obtained and the performance of the TRSS was also evaluated on tissue models made of silicone, biological tissue and resected whole human prostates in order to detect presence of PCa. Prostate glands are generally spherical and a special rotatable sample holder was included in the TRSS. Spherically shaped objects and uneven surfaces call for special attention to the contact angle between the sensor-tip and the measured surface, which has been evaluated. The indentation velocity and the depth sensitivity of the sensor were evaluated as well as the effect on the measurements caused by the force with which spherical samples were held in place in the sample holder. Measurements were made on silicone models and biological tissue of chicken and pork muscles, with embedded stiff silicone nodules, both on flat and spherical shaped samples. Finally, measurements were made on two excised whole human prostates.ResultsA contact angle deviating ≤ 10° from the perpendicular of the surface of the measured object was acceptable for reliable measurements of the stiffness parameter. The sensor could detect stiff nodules ≤ 4 mm under the surface with a small indentation depth of 0.4 to 0.8 mm.Measurements on the surface of resected human prostate glands showed that the TRSS could detect stiff areas (p < 0.05), which were confirmed by histopathological evaluation to be cancer tumours on, and under the surface.Conclusions A flexible resonance sensor system was designed and evaluated on soft tissue models as well as resected whole prostate glands. Evaluations on the tissue models showed that the TRSS can detect stiffer volumes hidden below the surface on both flat and spherical samples. The measurements on resected human prostate glands showed that PCa could be detected both on and under the surface of the gland. Thus the TRSS provides a promising instrument aimed for stiffness measurements of soft human tissue that could contribute to a future quantitative palpation method with the purpose of diagnosing cancer.
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| 24. |
- Åstrand, Anders P, et al.
(författare)
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Detection of stiff nodules embedded in soft tissue phantoms, mimicking cancer tumours, using a tactile resonance sensor
- 2014
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Ingår i: Journal of Biomedical Science and Engineering. - : Scientific Research Publishing, Inc.. - 1937-6871 .- 1937-688X. ; 7, s. 181-193
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundProstate cancer (PCa) is the most common form of cancer among males in Europe and in the USA and the most common curative treatment is removal of the prostate, i.e. prostatectomy. After the removal, the prostate is histopathologically analysed. One area of interest is to examine the capsule of the prostate, as tumours on and near the surface can indicate that the PCa has spread to other parts of the body. There are no current methods to examine the surface of the prostate at the time of surgery. Tactile resonance sensors can be used for detecting areas of different stiffness in soft tissue. Human prostate tissue affected by cancer is usually stiffer than healthy tissue, and for this purpose a tactile resonance sensor was developed. The aim of this study was to investigate the depth at which embedded stiffer volumes could be detected, using soft tissue phantoms.MethodsWith the tactile resonance sensor used in this study, the shift of the resonance frequency and the force at contact with tissue can be measured, and combined into a tissue stiffness parameter. The detection sensitivity of the sensor at impression depths, 0.4 and 0.8 mm, was measured for detection of an inserted nodules of stiff silicone in softer silicone and in chicken muscle tissue, mimicking prostate tissue with cancer tumours.ResultsMeasurements on the silicone samples detected the hidden stiffer object at a depth of 1-4 mm with a difference in the stiffness parameter of 80 – 900 mN/kHz (p < 0.028, n = 48). At the depth 5-6 mm the difference was smaller but still significant < 30 mN/kHz (p < 0.05, n = 24). For the measurements on chicken muscle, the detectable depth was 4 mm (p < 0.05, n = 24).ConclusionThis model study suggests that, with only a small impression depth of ≤ 1 mm, the resonance sensor system described here can detect stiffness variations located at least 4 mm in silicone and chicken muscle, mimicking tumours in prostate tissue.
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| 25. |
- Åstrand, Anders P., et al.
(författare)
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Initial measurements on whole human prostate ex vivo with a tactile resonance sensor in order to detect prostate cancer
- 2015
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Ingår i: 16th Nordic-Baltic Conference on Biomedical Engineering. - Cham : Springer. - 9783319129662 - 9783319129679 ; , s. 120-123
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Konferensbidrag (refereegranskat)abstract
- Prostate cancer (PCa) is the most common form of cancer among the male population in Europe and the USA. PCa can be suspected by a blood test for a specific prostate antigen, a PSA-test, followed by a digital rectal examination (DRE). The objective with the DRE is to investigate the presence of stiff nodules on the prostate. Stiff nodules can indicate PCa and biopsies are taken from the suspicious parts of the prostate using guidance of a transrectal ultrasound. Microscopic evaluation of the biopsies is used for final diagnosis. Superficial tumor growth on, and beneath the surface of the gland is of special interest as it suggests that the cancer has spread to other parts of the body.Tactile resonance sensors can be used to distinguish between areas of different stiffness in soft tissue. The aim was to detect tumors on, and beneath the surface of a whole human prostate ex vivo.A tactile resonance sensor system (TRSS) based on a piezoelectric resonance sensor and a force sensor has been used to detect areas with increased stiffness in soft tissue. The TRSS has a rotatable sample holder for measurements on spherical shaped samples. Stiffness measurements were made on samples of porcine muscle tissue with embedded stiff silicone nodules placed under the surface. Further measurements were made on a resected whole human prostate with PCa.The results showed that through the measured stiffness parameter, the stiff silicone nodules placed down to 4 mm under the surface could be detected. The measurements on the prostate showed that elevated values of the stiffness parameter correlated (p < 0.05) with areas in the anterior of the prostate where cancer tumors were detected by histopathological evaluation. The tumors were significantly stiffer than the healthy tissue in the dorsal region.The results are promising for further development of a clinically useful instrument to detect superficial PCa.
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| 26. |
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| 27. |
- Åstrand, Anders, et al.
(författare)
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The first study on whole human prostate ex vivo using a tactile resonance sensor for cancer detection
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Prostate cancer (PCa) is the most common form of cancer among males in Europe and the USA. A prostatectomy i.e. the removal of the prostate is the most common form of curative treatment. Prostate cancer can be suspected by a blood test for a prostate specific antigen (PSA) and a digital rectal examination (DRE) where a physician palpates the prostate through the rectum and where stiff nodules on the prostate is an indication for PCa. The final diagnosis of PCa is made by microscopic evaluation of ultrasound-guided biopsies taken from suspicious parts of the gland. After a prostatectomy the entire prostate is histopathologically analysed. One area of interest is the superficial part of the prostate gland as tumour growth on the surface suggests that the cancer has spread to other parts of the body. Tactile resonance sensors can be used to detect areas of different stiffness in soft tissue through a stiffness parameter. It is suggested that tactile resonance sensors can be used to detect prostate cancer since tumours in the human prostate usually is stiffer compared to surrounding healthy glandular tissue. The aim of the study was to detect tumours on, and beneath the surface, of whole human prostate glands ex vivo using a tactile resonance sensor system (TRSS). Model studies on spherical shaped tissue phantoms made of silicone and porcine tissue were performed to evaluate the ability of the TRSS to detect stiffer volumes at a distance beneath the surface. Finally two resected human prostate glands ex vivo from patients undergoing surgery for prostate cancer were studied. From the results it was concluded that the clamping force from the rotatable sample holder did not affect the magnitude of the stiffness parameter for the silicone samples. For the porcine muscle samples, the stiffness parameter showed to be affected by clamping forces larger than about 800 mN. The embedded stiff silicone nodules placed about 4 mm under the surface could be detected in both the silicone and biological tissue models with a sensor indentation distance of 0.6 mm. The measurements on resected whole human prostates showed that areas with elevated stiffness parameter values correlated (p < 0.05) with areas where cancer tumours were detected using histolopathological evaluation of the prostate. The tumours were significantly stiffer than the healthy tissue in the dorsal region. This is promising for the development of a clinically useful instrument to detect superficial prostate cancer.
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| 28. |
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