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Träfflista för sökning "WFRF:(Ljungberg Börje) ;pers:(Bergh Anders)"

Sökning: WFRF:(Ljungberg Börje) > Bergh Anders

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1.
  • Candefjord, Stefan, et al. (författare)
  • Combining scanning haptic microscopy and fibre optic Raman spectroscopy for tissue characterization
  • 2012
  • Ingår i: Journal of Medical Engineering & Technology. - : Taylor & Francis. - 0309-1902 .- 1464-522X. ; 36:6, s. 319-327
  • 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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  • Jacobsen, Jan, 1957- (författare)
  • Vascular endothelial growth factor in renal cell carcinoma
  • 2006
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Background. Angiogenesis is essential for tumour growth. Vascular endothelial growth factor (VEGF) and its isoforms were investigated in relation to the clinical course in a large number of patients with renal cell carcinoma (RCC). Methods. RCC subtypes and behaviour were established by clinicopathological criteria and surveillance. VEGF expression was analysed in serum by enzyme-linked immuno-sorbent assay (ELISA) and in tumour tissue by reverse transcription polymerase chain reaction (RT-PCR), immunohistochemistry (IHC), and Western blot (WB). Results. Serum VEGF (S-VEGF) was increased in RCC compared to control group. S-VEGF correlated with tumour stage and grade and was associated with survival in men but not in women. S-VEGF correlated with blood platelet counts, which were inversely correlated to increasing age in women, and they were decreased in chronically medicated patients, particularly in men. In contrast to S-VEGF, platelet counts associated with survival only in patients free of medication and chronic diseases. RT-PCR showed a correlation between VEGF121/VEGF165 mRNA and between VEGF165/VEGF-R1 mRNA. There was no association between different VEGF mRNA isoforms and S-VEGF. Conventional renal cell carcinoma (CRCC) had higher VEGF165, VEGF121, and VEGF-R1 mRNA levels compared with papillary renal cell carcinoma (PRCC). IHC VEGF staining was strong in kidney cortex. Kidney tumour showed a considerable variation in cytoplasmatic VEGF expression, which correlated with tumour size. Although, there was no difference in VEGF expression between the RCC types, VEGF expression was associated with survival only in CRCC. WB showed a strong protein expression of both VEGF189 and VEGF165 in kidney cortex. In kidney tumour, expression of VEGF189 varied the most, VEGF165 less so, and VEGF121 was rarely detected. Both CRCC and PRCC expressed low levels of VEGF189 and VEGF165 compared with kidney cortex. Chromophobe renal cell carcinoma (ChRCC) expressed VEGF189 levels comparable to those from kidney cortex, while VEGF165 was lower. In PRCC and ChRCC, VEGF189 levels correlated inversely with advancing tumour stage, and in PRCC, VEGF165 levels correlated inversely with increasing tumour size. VEGF189 was an independent prognostic factor for survival in patients with PRCC. Conclusions. S-VEGF has a stronger association to progression in RCC than platelet count. CRCC showed high levels of VEGF mRNA isoforms and VEGF-R1 mRNA compared to PRCC. VEGF mRNA isoforms expression decreased with advancing stage. IHC demonstrated VEGF expression in cell cytoplasm related to tumour growth, particular in CRCC. Different VEGF isoform patterns were found in different RCC types. Protein VEGF189 expression was associated with tumour stage and was an independent prognostic factor in PRCC. Protein VEGF165 expression was generally low and had no prognostic value. The trend for decreasing levels of VEGF isoforms in advanced tumour stages may indicate that angiogenic activity is an early event in tumour growth induced by VEGF, but that during later tumour progression the role of VEGF is less clear.
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  • Jalkanen, Ville, 1978-, et al. (författare)
  • Explanatory models for a tactile resonance sensor system-elastic and density-related variations of prostate tissue in vitro
  • 2008
  • Ingår i: Physiological Measurement. - Bristol : IOP Publ. Ltd. - 0967-3334 .- 1361-6579. ; 29:7, s. 729-745
  • Tidskriftsartikel (refereegranskat)abstract
    • Tactile sensors based on piezoelectric resonance have been adopted for medical applications. The sensor consists of an oscillating piezoelectric sensor–circuit system, and a change in resonance frequency is observed when the sensor tip contacts a measured object such as tissue. The frequency change at a constant applied force or mass load is used as a stiffness-sensitive parameter in many applications. Differential relations between force and frequency have also been used for monitoring intraocular pressure and stiffness variations in prostate tissue in vitro. The aim of this study was to relate the frequency change (Δf), measured force (F) and the material properties, density and elasticity to an explanatory model for the resonance sensor measurement principle and thereby to give explanatory models for the stiffness parameters used previously. Simulations of theoretical equations were performed to investigate the relation between frequency change and contact impedance. Measurements with a resonance sensor system on prostate tissue in vitro were used for experimental validation of the theory. Tissue content was quantified with a microscopic-based morphometrical method. Simulation results showed that the frequency change was dependent upon density (ρ) and contact area (S) according to Δf ∝ ρS3/2. The experiments followed the simulated theory at small impression depths. The measured contact force followed a theoretical model with the dependence of the elastic modulus (E) and contact area, F ∝ ES3/2. Measured density variations related to histological variations were statistically weak or non-significant. Elastic variations were statistically significant with contributions from stroma and cancer relative to normal glandular tissue. The theoretical models of frequency change and force were related through the contact area, and a material-dependent explanatory model was found as Δf ∝ ρE−1F. It explains the measurement principle and the previously established stiffness parameters from the material properties point of view.
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6.
  • Jalkanen, Ville, et al. (författare)
  • Indentation loading response of a resonance sensor : discriminating prostate cancer and normal tissue
  • 2013
  • Ingår i: Journal of Medical Engineering & Technology. - : Taylor & Francis. - 0309-1902 .- 1464-522X. ; 37:7, s. 416-423
  • Tidskriftsartikel (refereegranskat)abstract
    • Prostate cancer is the most common type of cancer among men worldwide. Mechanical properties of prostate tissue are promising for distinguishing prostate cancer from healthy prostate tissue. The aim was to investigate the indentation loading response of a resonance sensor for discriminating prostate cancer tissue from normal tissue. Indentation measurements were done on prostate tissue specimens ex vivo from 10 patients from radical prostatectomy. The measurement areas were analysed using standard histological methods. The stiffness parameter was linearly dependent on the loading force (average R2 = 0.90) and an increased loading force caused a greater stiffness contrast of prostate cancer vs normal tissue. The accuracy of the stiffness contrast was assessed by the ROC curve with the area under the curve being 0.941 for a loading force of 12.8 mN. The results are promising for the development of a resonance sensor instrument for detecting prostate cancer.
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7.
  • Jalkanen, Ville, 1978-, et al. (författare)
  • Prostate tissue stiffness as measured with a resonance sensor system : a study on silicone and human prostate tissue in vitro.
  • 2006
  • Ingår i: Medical and Biological Engineering and Computing. - : Springer Science and Business Media LLC. - 0140-0118 .- 1741-0444. ; 44:7, s. 593-603
  • Tidskriftsartikel (refereegranskat)abstract
    • Prostate cancer is the most common form of cancer in men in Europe and in the USA. Some prostate tumours are stiffer than the surrounding normal tissue, and it could therefore be of interest to measure prostate tissue stiffness. Resonance sensor technology based on piezoelectric resonance detects variations in tissue stiffness due to a change in the resonance frequency. An impression-controlled resonance sensor system was used to detect stiffness in silicone rubber and in human prostate tissue in vitro using two parameters, both combinations of frequency change and force. Variations in silicone rubber stiffness due to the mixing ratio of the two components could be detected (p<0.05) using both parameters. Measurements on prostate tissue showed that there existed a statistically significant (MANOVA test, p<0.001) reproducible difference between tumour tissue (n=13) and normal healthy tissue (n=98) when studying a multivariate parameter set. Both the tumour tissue and normal tissue groups had variations within them, which were assumed to be related to differences in tissue composition. Other sources of error could be uneven surfaces and different levels of dehydration for the prostates. Our results indicated that the resonance sensor could be used to detect stiffness variations in silicone and in human prostate tissue in vitro. This is promising for the development of a future diagnostic tool for prostate cancer.
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  • Jalkanen, Ville, 1978-, et al. (författare)
  • Resonance sensor measurements of stiffness variations in prostate tissue in vitro : a weighted tissue proportion model
  • 2006
  • Ingår i: Physiological Measurement. - : IOP Publishing. - 0967-3334 .- 1361-6579. ; 27:12, s. 1373-86
  • Tidskriftsartikel (refereegranskat)abstract
    • Prostate cancer is the most common type of cancer in men in Europe and the US. The methods to detect prostate cancer are still precarious and new techniques are needed. A piezoelectric transducer element in a feedback system is set to vibrate with its resonance frequency. When the sensor element contacts an object a change in the resonance frequency is observed, and this feature has been utilized in sensor systems to describe physical properties of different objects. For medical applications it has been used to measure stiffness variations due to various patho-physiological conditions. In this study the sensor's ability to measure the stiffness of prostate tissue, from two excised prostatectomy specimens in vitro, was analysed. The specimens were also subjected to morphometric measurements, and the sensor parameter was compared with the morphology of the tissue with linear regression. In the probe impression interval 0.5-1.7 mm, the maximum R(2) > or = 0.60 (p < 0.05, n = 75). An increase in the proportion of prostate stones (corpora amylacea), stroma, or cancer in relation to healthy glandular tissue increased the measured stiffness. Cancer and stroma had the greatest effect on the measured stiffness. The deeper the sensor was pressed, the greater, i.e., deeper, volume it sensed. Tissue sections deeper in the tissue were assigned a lower mathematical weighting than sections closer to the sensor probe. It is concluded that cancer increases the measured stiffness as compared with healthy glandular tissue, but areas with predominantly stroma or many stones could be more difficult to differ from cancer.
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