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排序方式: 共有625条查询结果,搜索用时 46 毫秒
1.
Erkan Yildirim Erkan Kaptanoglu Kanat Ozisik Ethem Beskonakli Ozerk Okutan Mustafa F Sargon Kamer Kilinc Unal Sakinci 《European journal of cardio-thoracic surgery》2004,25(4):523-529
OBJECTIVE: We aimed to demonstrate the time-dependent ultrastructural changes in pneumocyte type II cells following brain injury, and to propose an electron microscopic scoring model for the damage. METHODS: Forty Wistar-Albino female rats weighing 170-200 g were used. The rats were allocated into five groups. The first group was the control and the second was the craniotomy without trauma. The others were trauma groups. Weight-drop method was used for achieving head trauma. Samples were obtained from the right and left pulmonary lobes at 2-, 8-, and 24-h intervals after transcardiac perfusion. An electron microscopic scoring model was used to reveal the changes. RESULTS: There were no ultrastructural pathological findings pointing to lung injury in any rat of the control groups. There was intense intracellular oedema in type II pneumocyte and interstitial oedema in the adjacent tissue in trauma groups. Oedema in mitochondria and dilatation in both smooth endoplasmic reticulum and Golgi apparatus was more evident in the 8- and 24-h trauma groups. The chromatin dispersion was disintegrated in the nucleus in all trauma groups. Scores of all trauma groups were significantly different from the controls (P<0.05). All trauma groups were different from each other at significant levels (P<0.05 for each trauma groups). CONCLUSIONS: The data suggested that ultrastructural damage is obvious at 2 h and deteriorates with time. The electron microscopic scoring model worked well in depicting the traumatic changes, which were supported by lipid peroxidation. Further experiments are needed to determine the exact outcome after brain death model. 相似文献
2.
Kroeze H Van de Kamer JB De Leeuw AA Lagendijk JJ 《Physics in medicine and biology》2001,46(7):1919-1935
Recently published results confirm the positive effect of regional hyperthermia combined with external radiotherapy on pelvic tumours. Several studies have been published on the improvement of RF annular array applicator systems with dipoles and a closed water bolus. This study investigates the performance of a next-generation applicator system for regional hyperthermia with a multi-ring annular array of antennas and an open water bolus. A cavity slot antenna is introduced to enhance the directivity and reduce mutual coupling between the antennas. Several design parameters, i.e. dimensions, number of antennas and operating frequency, have been evaluated using several patient models. Performance indices have been defined to evaluate the effect of parameter variation on the specific absorption rate (SAR) distribution. The performance of the new applicator type is compared with the Coaxial TEM. Operating frequency appears to be the main parameter with a positive influence on the performance. A SAR increase in tumour of 1.7 relative to the Coaxial TEM system can be obtained with a three-ring, six-antenna per ring cavity slot applicator operating at 150 MHz. 相似文献
3.
Treatment planning for capacitive regional hyperthermia. 总被引:1,自引:0,他引:1
H Kroeze J B van de Kamer A A C de Leeuw M Kikuchi J J W Lagendijk 《International journal of hyperthermia》2003,19(1):58-73
Capacitively coupled hyperthermia devices are widely in use, mainly in Asian countries. In this paper, a comprehensive treatment planning system, including a Specific Absorption Rate (SAR) and thermal model for capacitively coupled hyperthermia, is described and demonstrated using a heterogeneous patient model. In order to accurately model a hyperthermia treatment, simulation at high resolution is mandatory. Using the quasi-static approximation, the electromagnetic problem can be solved at high resolution with acceptable computational effort. The validity of the quasi-static approximation is demonstrated by comparing the Maxwell solution of a phantom problem to the quasi-static approximation. Modelling of capacitive hyperthermia of the prostate reveals the difficulty of heating deep-seated tumours in the pelvic area. Comparison of the SAR distribution in the heterogeneous patient model and a patient shaped agar phantom shows a shielding effect of the pelvic bone and the influence of the fat-muscle distribution. It is shown that evaluation of capacitive hyperthermia with agar phantoms leads to overly optimistic conclusions. Therapeutic relevant tumour temperatures can only be obtained by permitting temperature extrema in normal tissue. This concurs with clinical practice, where treatment-limiting hot spots restrict the tumour temperature. It is demonstrated that the use of very cold overlay bolus bags has only a very superficial effect. The presented model can be used for individual treatment planning and optimization, for the evaluation of capacitive applicator modifications and comparison with other devices. 相似文献
4.
5.
Ghizlane Genc İlken Kocadereli Ferda Tasar Kamer Kilinc Sibel El Bahram Sarkarati 《Lasers in medical science》2013,28(1):41-47
The aim of this study is to evaluate the effects of low-level laser therapy (LLLT) on (1) the velocity of orthodontic tooth movement and (2) the nitric oxide levels in gingival crevicular fluid (GCF) during orthodontic treatment. The sample consisted of 20 patients (14 girls, six boys) whose maxillary first premolars were extracted and canines distalized. A gallium-aluminum-arsenide (Ga-Al-As) diode laser was applied on the day 0, and the 3rd, 7th, 14th, 21st, and 28th days when the retraction of the maxillary lateral incisors was initiated. The right maxillary lateral incisors composed the study group (the laser group), whereas the left maxillary lateral incisors served as the control. The teeth in the laser group received a total of ten doses of laser application: five doses from the buccal and five doses from the palatal side (two cervical, one middle, two apical) with an output power of 20 mW and a dose of 0.71 J /cm2. Gingival crevicular fluid samples were obtained on the above-mentioned days, and the nitric oxide levels were analyzed. Bonferroni and repeated measures variant analysis tests were used for statistical analysis with the significance level set at p ≤ 0.05. The application of low-level laser therapy accelerated orthodontic tooth movement significantly; there were no statistically significant changes in the nitric oxide levels of the gingival crevicular fluid during orthodontic treatment. 相似文献
6.
7.
Dominic Gehweiler Teun Teunis Viktor Varjas Dirk Kerstan Boyko Gueorguiev Lukas Kamer Hansrudi Noser 《Clinical anatomy (New York, N.Y.)》2019,32(3):361-368
Distal radius fractures are common and fracture patterns and fixation can be complex. Computerized anatomy evaluation (CAE) might offer non‐invasive and enhanced anatomy assessment that might help with implant selection and placement and screw length determination. Our goal was to test the accuracy of two CAE methods for anatomical volar plate positioning and screw lengths measurement of the distal radius. We included 56 high‐resolution peripheral quantitative computed tomography scans of intact, human distal radii. Plates were placed manually onto 3D printed models (method 1), which was compared with automated computerized plate placement onto the 3D computer models (method 2). Subsequently, screw lengths were determined digitally for both methods. Screw lengths evaluations were compared via Bland–Altman plots. Both CAE methods resulted in identical volar plate selection and in anatomical plate positioning. For screw length the concordance correlation coefficient was ≥0.91, the location shift ≤0.22 mm, and the scale shift ≤0.16. The differences were smaller than ±1 mm in all samples. Both CAE methods allow for comparable plate positioning and subsequent screw length measurement in distal radius volar plating. Both can be used as a non‐invasive teaching environment for volar plate fixation. Method 2 even offers fully computerized assessments. Future studies could compare our models to other anatomical areas, post‐operative volar plate positioning, and model performance in actual distal radius fracture instead of intact radii. Clin. Anat. 32:361–368, 2019. © 2018 The Authors. Clinical Anatomy published by Wiley Periodicals, Inc. on behalf of American Association of Clinical Anatomists. 相似文献
8.
M. Van Vulpen A. A. C. De Leeuw J. B. Van De Kamer H. Kroeze T. A. Boon C. C. Wárlám-Rodenhuis 《International journal of hyperthermia》2013,29(5):481-497
A study was performed on regional hyperthermia for patients with locally advanced prostate carcinoma. The primary objective was to analyse the thermometry data with an emphasis on the possibility of replacing invasive thermometry by tumour-related intra-luminal thermometry. Fourteen patients were treated with a combination of conformal external beam radiotherapy (70 Gy) and hyperthermia. Hyperthermia was delivered using the Coaxial TEM system, one treatment per week, to a total of five treatments. Thermometry was performed in bladder, urethra, rectum and esophagus. Invasive thermometry in the prostate was carried out during one or two treatments for each patient by placing transperineally a central and a peripheral catheter. Heterogeneous temperature distributions were measured in the prostate. The mean average invasive temperature range was 1.1°C. Due to the temperature heterogeneity and a limited number of thermometry sensors (mean 7, range 2-13), large variability between treatments and patients existed regarding achieved temperatures and dose. The mean invasive T 90 was 40.2 - 0.6°C and T 50 was 40.8 - 0.6°C. The mean Cum min T 90 >40.5°C per treatment was 22 (range 0-50). Importantly, intra-luminal temperatures did not reliably predict invasively measured temperatures. Invasive thermometry, therefore, remains compulsory to calculate a thermal dose for an individual patient. Changes in temperature during treatment, measured by the urethral sensors, corresponded well with changes in temperature measured by the individual invasive sensors. Similar comparison of rectal temperature changes with intra-prostatic temperature changes was not as predictive. The similarity in temperature changes between the urethral and interstial sites, suggests that urethral temperatures are sufficient for treatment optimization. The SAR profile did not correspond with the temperature profile indicating heterogeneous perfusion. Although regional hyperthermia in combination with external beam radiotherapy for locally advanced prostate carcinoma is clinically feasible, the question on the importance of invasive thermometry remains. 相似文献
9.
10.
Muslum Kul Fatih Unal Hasan Kandemir Bahram Sarkarati Kamer Kilinc Sultan Basmac? Kandemir 《Psychiatry investigation》2015,12(3):361-366