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排序方式: 共有811条查询结果,搜索用时 15 毫秒
1.
Anu Juslin Jyrki L?tj?nen Sergey V Nesterov Kari Kalliokoski Juhani Knuuti Ulla Ruotsalainen 《Journal of nuclear cardiology》2007,14(1):82-91
BACKGROUND: The aim of this study was to develop a method to correct the heart position between two oxygen 15-labeled water cardiac positron emission tomography (PET) image sets to be able to use the equivalent regions of interest for the quantification of the perfusion values in the same myocardial segments. METHODS AND RESULTS: Independent component analysis was applied to the dynamic image sets (simulated phantom and 6 rest-pharmacologic stress and 10 rest-rest image sets of healthy female volunteers) acquired at different time points to separate the cardiac structures (ventricles and myocardium). The separated component images from independent component analysis from the 2 studies of the same individual were aligned with a normalized mutual information-based registration method. The alignment parameters were applied to position the regions of interest in the floating image sets for calculation of the myocardial blood flow values. In the rest case the mean myocardial blood flow value was 0.76 +/- 0.12 mL x g(-1) x min(-1) for the manual method and 0.79 +/- 0.10 mL x g(-1) x min(-1) for the proposed method (by use of the right ventricle component in the alignment), and in the stress case these values were 3.39 +/- 0.70 mL x g(-1) x min(-1) and 4.01 +/- 0.71 mL x g(-1) x min(-1), respectively. No statistically significant difference was found between the methods. CONCLUSION: In the tests with the phantom and patient images the alignment of cardiac structures was shown to be successful. The alignment could be done without the use of information from the myocardial compartment. 相似文献
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Pia Lautala Maija Kivimaa Hannele Salomies Eivor Elovaara Jyrki Taskinen 《Pharmaceutical research》1997,14(10):1444-1448
Purpose. Nitrocatechol COMT inhibitors are a new class of bioactive compounds, for which glucuronidation is the most important metabolic pathway. The objective was to characterize the enzyme kinetics of nitrocatechol glucuronidation to improve the understanding and predicting of the pharmacokinetic behavior of this class of compounds.
Methods. The glucuronidation kinetics of seven nitrocatechols and 4-nitrophenol, the reference substrate for phenol UDP-glucuronosyltrans-ferase activity, was measured in liver microsomes from creosote-treated rats and determined by non-linear fitting of the experimental data to the Michaelis-Menten equation. A new method that combined densitometric and radioactivity measurement of the glucuronides separated by HPTLC was developed for the quantification.
Results. Apparent Km values for the nitrocatechols varied greatly depending on substitution pattern being comparable with 4-nitrophenol (0.11 mM) only in the case of 4-nitrocatechol (0.19 mM). Simple nitrocatechols showed two-fold Vmax values compared with 4-nitrophenol (68.6 nmol min–1 mg–1), while all disubstituted catechols exhibited much lower glucuronidation rate. Vmax/Km values were about 10 times higher for monosubstituted catechols compared to disubstituted ones. The kinetic parameters for COMT inhibitors were in the following order: Km nitecapone >> entacapone > tolcapone; Vmax nitecapone > entacapone > tolcapone; Vmax/Km tolcapone > nitecapone > entacapone.
Conclusions. Nitrocatechols can in principle be good substrates of UGTs. However, substituents may have a remarkable effect on the enzyme kinetic parameters. The different behaviour of nitecapone compared to the other COMT inhibitors may be due to its hydrophilic 5-substituent. The longer elimination half-life of tolcapone in vivo compared to entacapone could not be explained by glucuronidation kinetics in vitro. 相似文献
4.
Marja Hilska Yrj? Collan Peter J Roberts Jari Ovaska Jyrki K?ssi Hannu Paajanen Matti Laato 《Acta chirurgica》2002,168(2):84-90
OBJECTIVE: To compare the ability of various methods of staging and grading to predict survival in proximal colon cancer. DESIGN: Retrospective study. SETTING: University hospital, Finland. SUBJECTS: 153 patients with primary proximal colon cancer. MAIN OUTCOME MEASURES: Staging by four classification systems, grading by two grading systems, and survival analysis based on Kaplan-Meier survival curves. RESULTS: In all staging systems the survival curves of different stages differed significantly from each other. The modified Dukes' classification was still the best predictor of survival. Grade of tumours had no significant effect on long term survival, but short term survival was affected adversely by the presence of anaplastic tissue. Tumours with no mucin had a worse prognosis than those that produced mucin. All staging methods were superior to either of the histological grading systems tested as prognosticators. Tumour depth correlated with the operator's clinical impression of radicality of operation, and also predicted survival. CONCLUSION: The clinicopathological modified Dukes' staging system was the most powerful prognosticator in proximal colonic cancer and its use in clinical practice should continue. Even a small amount of anaplastic tissue (> or = 5%) had an adverse effect on short term survival. 相似文献
5.
Pirkko Santavuori M.D Raili Raininko M.D Sanna-Leena Vanhanen M.D Jyrki Launes M.D Kimmo Sainio M.D 《Developmental medicine and child neurology》1992,34(1):61-65
Two patients with infantile neuronal ceroid lipofuscinosis are presented whose clinical diagnosis was based on the typical clinical picture, together with absent sleep spindles and MRI findings (hypointense thalami and hyperintense periventricular white matter) as early as 18 months in one girl. In addition to a flat cortical SEP, these abnormalities appeared earlier than the typical ERG and VEP findings used previously for clinical diagnosis of this condition. MRI of the other patient showed the same changes and EEG sleep spindles were absent by two years. 相似文献
6.
TK-GFP fusion gene virus vectors as tools for studying the features of HSV-TK/ganciclovir cancer gene therapy in vivo 总被引:2,自引:0,他引:2
Pasanen T Hakkarainen T Timonen P Parkkinen J Tenhunen A Loimas S Wahlfors J 《International journal of molecular medicine》2003,12(4):525-531
The fusion gene of herpes simplex virus thymidine kinase and green fluorescent protein (TK-GFP) was shown to be a versatile tool for examining the features of thymidine kinase/ganciclovir gene therapy in vitro. In this study, we used viral vectors carrying the fusion gene to characterize the aspects of this gene therapy form in rodent tumor models. Growth of subcutaneous 9L rat tumors transduced ex vivo with TK-GFP gene was prevented when ganciclovir (GCV) treatment was initiated immediately after tumor inoculation. Established tumors (>100 mm(3)), however, were untreatable despite the initial 55% proportion of TK-GFP positive cells. This was due to a rapid clearance of TK-GFP positive cells, but not GFP positive cells. Propidium iodide staining revealed that TK-GFP lentivirus vector was able to induce apoptosis/necrosis in 9L cells, as opposed to the respective GFP vector. Furthermore, when a subcutaneous nude mouse tumor model was used, the percentage of TK-GFP positive cells in vivo was maintained similarly as in cultured cells, suggesting contribution of a fully functional immune response to the disappearance of fusion gene positive cells. In vivo gene transfer studies: adenovirus TK-GFP vector injections resulted in about 25% gene transfer efficiency to 9L tumors and showed that their growth could be significantly reduced even when the tumor volumes were already >120 mm(3). Part of the effect was shown to be due to cytotoxicity of the vector. In summary, our results demonstrate the utility of TK-GFP fusion gene-carrying viral vectors in animal studies and show that readily detectable therapeutic genes can help us to understand the complicated nature of in vivo cancer gene therapy experiments. 相似文献
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Late onset type 1 alcoholism has been suggested to be associated with decreased dopaminergic transmission. Our hypothesis was that late onset type 1 alcoholics have also abnormal extrastriatal dopamine D(2)/D(3) receptor distribution. We performed binding, heterogeneity and laterality analysis of extrastriatal and striatal dopamine D(2)/D(3) receptors in nine late onset male alcoholics and in 12 age-matched healthy males. A radioligand, [(123)I]epidepride was used in high resolution single-photon emission tomography (SPET). Specific binding of epidepride in the left temporal pole was significantly (P<0.05) lower in type 1 alcoholics (0.74+/-0.14 ml/ml) than in controls (0.89+/-0.14 ml/ml). In alcoholics, there was no normal left-to-right asymmetry of the temporal cortical heterogeneity of epidepride distribution observed in control males (0.89+/-0.19 vs. 1.10+/-0.19; P<0.05). The results suggest that the specific binding of dopamine D(2)/D(3) receptors in late type 1 alcoholics is decreased and its laterality in the temporal brain is altered from normal. 相似文献
9.
The aim of the present study was to examine the expression of 1 integrin subunit after peripheral nerve transection. After sciatic nerve transection two experimental procedures were used; changes in the freely regenerating rat sciatic nerve were compared to a situation in which spontaneous regeneration was prevented by suturing both ends of the nerve to the muscle next to the point of transection. Specimens for morphological analysis were collected 6 h, 1, 3, 5, 7 days and 2, 4, 6 and 8 weeks after the axotomy. Sections from the proximal (two zones) and distal (three zones) stumps next to the point of transection were stained with antibodies against 1 integrin subunit, macrophages, collagen types I and III, and S-100 protein. The control nerves showed 1 integrin-stained cells in the perineurium and vasa nervorum but the endoncurium was negative. Positively stained endoneurial fibroblast-like cells could be seen in the proximal part of the nerve already at 24 h after transection. The number of these positively stained cells increased steadily; they were most numerous 4 weeks after transection in the distal zone 2. Subsequently, the number of positively stained endoneural cells declined sharply and 8 weeks after transection no positively stained cells could be found. The morphological appearance and the immunohistochemical properties of the cells suggest that the majority of 1 integrin-positive cells are endoneurial fibroblast-like cells. Thus, the process appeared to be dynamic, starting from the proximal part and continuing to the distal parts, and was similar in both experimental groups. The positive staining in perineurial cells indicate that 1 integrin, which is an important mediator of the cell-matrix interaction, may have an essential role in the formation and strengthening of the normal peripheral nerve structures. Furthermore, 1 integrin seems to have an active role in reactions which occur during the early phases of peripheral nerve regeneration. 相似文献
10.
Infiltrative capacity was found to distinguish separate T leukemia cell lines. Of seven T-cell lines four exhibited capacity
to infiltrate Matrigel. Analysis of infiltration was performed at the single-cell level throughout the Matrigel using a depth
meter. Further, we examined differences in migration capacity and metalloproteinase production between infiltrating and non-infiltrating
T-cell lines. The capacity to infiltrate was not directly correlated to the capacity to adhere to the Matrigel or to migrate
on/to extracellular matrix components. It is concluded that infiltration capacity does not simply reflect capacity to migrate
but represents a distinct functional property. The production of metalloproteinases and their inhibitors by the separate T-cell
lines was analyzed using rt PCR, biosynthetic labelling, zymography, immunoprecipitation and ELISA. All T-cell lines with
capacity to infiltrate produced matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-1 (TIMP-1) while
non-infiltrating cell lines did not express MMP-9. Expression of MMP-1, 2, 3, 10, 14 and 17 showed no correlation to capacity
to infiltrate. Analysis of infiltration in the presence of a metalloprotease inhibitor showed an increased number of cells
within the gel. This enhancement of infiltration suggests that the function of MMPs and/or their inhibitors in lymphocyte
infiltration is more complex than previously thought.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献