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- Andersson-Engels, Stefan, et al.
(author)
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Laser-induced fluorescence used in localizing atherosclerotic lesions
- 1989
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In: Lasers in Medical Science. - 0268-8921. ; 4:3, s. 171-181
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Journal article (peer-reviewed)abstract
- We have investigated laser-induced fluorescence frompost mortem human arteries in order to find spectroscopic properties allowing discrimination between normal and atherosclerotic vessel wall. A pulsed nitrogen laser emitting light at a wavelength of 337.1 nm was used as an excitation source. The fluorescence spectrum from 370 to 700 nm was captured and analysed by an optical multichannel analyser. Dimensionless contrast functions were formed by using characteristic spectral features at 390, 415, 480, 580 and 600 nm. All samples were investigated in scans across a region where normal as well as diseased vessel wall appeared. The types of plaque were histopathologically divided into four groups, of which three could be singled out using one or more of our spectroscopic criteria. We also investigated the different layers of the normal and diseased vessel wall in order to determine the various contributions to the fluorescence signal. Furthermore, plasma emission spectra were recorded while ablating the normal as well as the diseased vessel wall with an excimer laser, emitting radiation at 308 nm, thus detecting the change in spectral characteristics during the ablation process down into deeper layers.
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| 3. |
- Andersson-Engels, Stefan, et al.
(author)
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Malignant-tumor and Atherosclerotic Plaque Diagnosis Using Laser-induced Fluorescence
- 1990
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In: IEEE Journal of Quantum Electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0018-9197. ; 26:12, s. 2207-2217
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Journal article (peer-reviewed)abstract
- A review of tissue diagnostics using laser-induced fluorescence is given with illustrations chosen from work performed by the Lund group. Two major topics are considered: the demarcation of malignant tumors from normal surrounding tissue and the identification of atherosclerotic regions in arteries. Specific fluorescence from injected agents as well as tissue natural autofluorescence is discussed. Steady-state, as well as time-resolved fluorescence can be utilized. Furthurmore, original data showing immunity to blood interference in artery monitoring are presented. Finally, imaging techniques for diseased tissue real-time visualization are discussed and illustrated.
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| 5. |
- Liu, D. L, et al.
(author)
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Beneficial-effects of Platelet-activating-factor Receptor Antagonist Web-2170 On 90-minute Hepatic Inflow Interruption
- 1994
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In: European Journal of Gastroenterology and Hepathology. - 1473-5687. ; 6:11, s. 1015-1022
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Journal article (peer-reviewed)abstract
- Objective: To study the effects of different doses of platelet activating factor receptor antagonist WEB 2170 on animal survival, haemodynamics, reperfusion and ultrastructural changes in the ischaemic liver in rats undergoing 90-min total hepatic inflow interruption (THII). Design: Sixty-five rats were divided into five groups. All animals underwent 90-min THII. Group 1 served as controls. Group 2 underwent THII alone. Group 3 received an intravenous injection of 1 mg/kg WEB 2170 prior to THII. Group 4 received a bolus injection of 3 mg/kg WEB 2170 before THII. Group 4 received a bolus injection of 3 mg/kg WEB 2170 before THII. Group 5 received 3 mg/kg WEB 2170 before, during and after THII. The liver reperfusion index using laser Doppler flowmetry, the time of ischaemic liver initiative reperfusion, and scanning electron microscopy were performed to evaluate the results of different dose schedules. Setting: Lund University Hospital, Lund, Sweden. Results: Animal survival rate, liver reperfusion index, the time of ischaemic liver initiative reperfusion and ultrastructural damage of the ischaemic liver were markedly improved in the groups treated with WEB 2170 compared with the non-treated 90-min THII group. The best result was obtained in the group receiving the three separate doses. Conclusion: In the 90-min THII model, WEB 2170 protects the liver from ischaemia-reperfusion injury and the spread of damage to the post-stasis splanchnic organs. These beneficial effects may be extended to hepatic transplantation or major resections of the liver.
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| 8. |
- Pålsson, Sara, et al.
(author)
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Methods for detailed histopathological investigation and localization of biopsies from cervix uteri to improve the interpretation of auto fluorescence data
- 2006
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In: Journal of Environmental Pathology and Toxicology. - 2162-6537. ; 25:1-2, s. 321-340
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Journal article (peer-reviewed)abstract
- Fluorescence spectroscopy is one of many optical methods that are potentially clinically useful for noninvasive detection and characterization of disorders on the cervical part of uterus, including precancerous lesions. The cervix uteri exhibits a biologically complex tissue and the morphology of a biopsy is generally not homogenous. The standard histopathological protocol accounts only for the most severe condition found within the biopsy and no information is given on other constituents potentially influencing the recorded fluorescence spectra. Spectra are usually correlated, using multivariate techniques, to the histopathological diagnosis of the biopsies. Since the probe volume of fluorescence spectroscopy is considerably smaller than the extension of the biopsy, this can cause problems in the search for correlation between the fluorescence signals and the pathological structures. In addition, the orientation and location of the biopsies are normally not recorded. We now report on the first detailed histopathological protocol where numerous tissue parameters, such as thickness and type of the epithelium and the number of blood vessels, glands, and inflammatory cells, are tabulated and the orientation and location of the biopsy are recorded as precisely as possible. Hopefully, the use of this protocol together with sophisticated mathematical methods will increase the probability to classify cervical disorders of the uterus, including precancerous lesions, with high sensitivity and specificity.
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| 9. |
- Soto Thompson, Marcelo, et al.
(author)
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Photodynamic therapy of nodular basal cell carcinoma with multifiber contact light delivery
- 2006
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In: Journal of Environmental Pathology and Toxicology. - 2162-6537. ; 25:1-2, s. 411-424
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Journal article (peer-reviewed)abstract
- To overcome the limited treatment depth of superficial photodynamic therapy we investigate interstitial light delivery. In the present work the treatment light was delivered using a system in which three or six clear-cut fibers were placed in direct contact with the tumor area. This placement was thought to represent a step toward general purpose interstitial PDT. Twelve nodular basal cell carcinomas were treated employing delta-aminolevulinic acid and 635 nm laser irradiation. Fluorescence measurements were performed monitoring the buildup and subsequent bleaching of the produced sensitizer protoporphyrin IX. The treatment efficacy, judged at a 28-month follow-up, showed a 100% complete response. Two punch excisions at 7 months converted two partial responses to complete responses. One patient failed to appear at all follow-up sessions. The outcome of the treatments was comparable to superficial photodynamic therapy in terms of histological, clinical, and cosmetic results.
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| 10. |
- Stenberg, M, et al.
(author)
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Interstitial photodynamic therapy - diagnostic measurements and treatment in rat malignant experimental tumours
- 2000
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In: OPTICAL BIOPSY AND TISSUE OPTICS. - : SPIE. - 1996-756X .- 0277-786X. - 0819438170 ; 4161:32, s. 151-157
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Conference paper (peer-reviewed)abstract
- A recently developed multiple fibre system for treating malignant tumours with interstitial photodynamic therapy was used in studies on rats with colon adenocarcinoma inoculated into the muscles of the hind legs. The animals were intraperitonially administrated delta -aminolevulinic acid (ALA), which is metabolised to protoporphyrin IX (PpIX) in the tissue. The treatment system consists of a laser light source, a beam-splitting system dividing the light into three or six output fibres and a dosimetry programme calculating the optimal fibre position within the tumour as well as the treatment time needed to obtain a given threshold value of the light dose. One aim of the study was to compare the treatment outcome with the modelled dosimetry predictions. Tumour reduction was examined three days post treatment. A volume decrease was found in 85\% of the treated tumours. The mean volume reduction was 44\%, with one tumour completely disappearing. Histopathological examination three days post treatment showed substantial necrotic parts which, however, to a smaller extent were present also for non-treated tumours. These results indicated that the tumours have been under treated and the light dose has to be increased. Measurements of the build-up and photo-induced bleaching of PpIX using laser-induced fluorescence were also performed during the experiments.
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