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991.
992.
Azizuddin K Kalka K Chiu SM Ahmad N Mukhtar H Separovic D 《International journal of oncology》2001,18(2):411-415
Photodynamic therapy (PDT) is a novel cancer treatment utilizing a photosensitizer, visible light and oxygen. PDT with the silicon phthalocyanine Pc 4, a new photosensitizer, is highly effective in cancer cell destruction and tumor ablation. The mechanisms underlying cancer cell killing by PDT are not fully understood. Tumor necrosis factor alpha (TNF) is a multifunctional cytokine that has been implicated in photocytotoxicity. We asked whether recombinant human TNF (rhTNF) affects Pc 4-PDT cytotoxicity in A431 human epidermoid carcinoma cells. Co-treatment of A431 cells with various doses of Pc 4-PDT and a sub-lethal rhTNF dose led to a sub-additive reduction in cell survival. In addition, in the presence of Pc 4-PDT or rhTNF, caspase-3 activity and apoptosis were induced. The combined treatment, however, did not potentiate either caspase-3 activity or apoptosis. Similar to previous findings we observed that Pc 4-PDT initiated a time-dependent extracellular TNF accumulation. The data suggest that: a) PDT and rhTNF induce cancer cell killing through different mechanisms; and b) Pc 4-PDT-induced TNF production is a stress response that may not directly affect photocytotoxicity. 相似文献
993.
Cell adhesion molecules are important for localized accumulation of phagocytes at sites of tissue damage. In the present studies, we analyzed the effects of blocking hepatic macrophages on expression of beta2 integrins and intercellular adhesion molecule-1 (ICAM-1) adhesion molecules on liver cells during acute endotoxemia. Flow cytometric analysis revealed distinct subpopulations of macrophages from control animals that varied on the basis of their size and density. In contrast, hepatocytes and endothelial cells were relatively homogeneous. Treatment of rats with endotoxin (5 mg/kg, intravenously) resulted in a time-dependent increase in the percentage of small, dense macrophages and a progressive loss of larger, less-dense cells. In contrast, no major effects were observed on the physical properties of hepatocytes or endothelial cells. ICAM-1 was found to be constitutively expressed on endothelial cells and hepatocytes, as well as on macrophages. Induction of acute endotoxemia resulted in a time-dependent increase in ICAM-1 expression on hepatocytes, which was observed within 3 hours and reached a maximum after 24 hours. An increase in ICAM-1 expression was also observed on endothelial cells and on macrophages at 3 hours, followed by a decrease at 24 to 48 hours. Macrophages and endothelial cells also constitutively expressed beta2 integrins. Induction of acute endotoxemia had no effect on beta2 integrin expression by these cells. Pretreatment of rats with gadolinium chloride (GdCl3), a macrophage inhibitor known to block endotoxin-induced liver injury, abrogated the effects of endotoxin on ICAM-1 expression by hepatocytes and macrophages. In contrast, ICAM-1 expression on endothelial cells increased. Interestingly, treatment of rats with GdCl3 alone resulted in a marked increase in expression of ICAM-1 on endothelial cells and hepatocytes, and of beta2 integrins on macrophages and endothelial cells. Taken together, these data suggest that ICAM-1 is involved in mediating macrophage adherence and accumulation in the liver during endotoxemia. Furthermore, macrophages appear to regulate expression of this cell adhesion molecule on parenchymal cells. 相似文献
994.
995.
Green tea in chemoprevention of cancer 总被引:13,自引:0,他引:13
The concept of prevention of cancer using naturally occurring substances
that could be included in the diet consumed by the human population is
gaining increasing attention. Tea, next to water, is the most popularly
consumed beverage in the world and it is grown in about 30 countries.
Abundant data, amassed from several laboratories around the world in the
last ten years, provided convincing evidence that polyphenolic antioxidants
present in tea afford protection against cancer risk in many animal-tumor
bioassay systems. The epidemiological studies, though inconclusive, have
also suggested that the consumption of tea is associated with a lowered
risk of cancer. Much of this work has been done on green tea; less is known
about black tea. Green tea contains many polyphenolic antioxidants, and
(-)-epigallocatechin-3- gallate (EGCG) is the key polyphenolic antioxidant
believed to be responsible for most of the cancer chemopreventive
properties of green tea. This review will discuss these effects and the
molecular mechanisms associated with the biological response to green-tea
polyphenols.
相似文献
996.
Use of positron emission tomography in evaluation of brachial plexopathy in breast cancer patients 总被引:2,自引:0,他引:2
18-Fluoro-2-deoxyglucose (FDG) positron emission tomography (PET) has previously been used successfully to image primary and metastatic breast cancer. In this pilot study, 19 breast cancer patients with symptoms/signs referrable to the brachial plexus were evaluated with 18FDG-PET. In 11 cases computerized tomography (CT) scanning was also performed. Of the 19 patients referred for PET study, 14 had abnormal uptake of 18FDG in the region of the symptomatic plexus. Four patients had normal PET studies and one had increased FDG uptake in the chest wall that accounted for her axillary pain. CT scans were performed in 9 of the 14 patients who had positive brachial plexus PET studies; six of these were either normal or showed no clear evidence of recurrent disease, while three CTs demonstrated clear brachial plexus involvement. Of two of the four patients with normal PET studies, one has had complete resolution of symptoms untreated while the other was found to have cervical disc herniation on magnetic resonance imaging (MRI) scan. The remaining two patients almost certainly had radiation-induced plexopathy and had normal CT, MRI and PET study. These data suggest that 18FDG-PET scanning is a useful tool in evaluation of patients with suspected metastatic plexopathy, particularly if other imaging studies are normal. It may also be useful in distinguishing between radiation-induced and metastatic plexopathy. 相似文献
997.
Srinivasula SM Ahmad M Guo Y Zhan Y Lazebnik Y Fernandes-Alnemri T Alnemri ES 《Cancer research》1999,59(5):999-1002
Alternatively spliced isoforms of certain apoptosis regulators, such as Bcl-x, Ced-4, and Ich-1, have been shown to play opposing roles in regulating apoptosis. Here, we describe the identification of an endogenous alternatively spliced isoform of caspase-9, named caspase-9b, which lacks the central large subunit caspase domain. Caspase-9b is detectable in many cell lines by PCR and at the mRNA and protein levels. Caspase-9b can interact with the caspase recruitment domain of Apaf-1, and like the active site mutant of caspase-9, it can inhibit multiple forms of apoptosis, including those triggered by oligomerization of death receptors. It can also block activation of caspase-9 and -3 by Apaf-1 in an in vitro cytochrome c-dependent caspase activation assay. These results suggest that caspase-9b functions as an endogenous apoptosis inhibitory molecule by interfering with the formation of a functional Apaf-1-caspase-9 complex. 相似文献
998.
Fatima M Ahmad I Sayeed I Athar M Raisuddin S 《Aquatic toxicology (Amsterdam, Netherlands)》2000,49(4):243-250
Pollutant-induced abnormal functioning of phagocytes and associated consequences were studied in freshwater catfish Heteropneustes fossilis (Bloch). Fish were exposed to effluent collected from bleached kraft type of paper mill at the concentration levels of 0.5, 1 and 2% for 15, 30, 60 and 90 days. Respiratory burst activity of peritoneal and head kidney phagocytes of exposed fish was measured by nitroblue tetrazolium reduction assay. Lipid peroxidation (LPO) was estimated in liver, gill and kidney of fish by measuring thiobarbituric acid reaction substances. It was observed that the phagocyte-activating xenobiotics of effluent induced an increase in the respiratory burst activity in phagocytes. The induction of respiratory burst activity was concomitantly associated with an increase in the peroxidative damage of tissues. The tissues most affected were kidney and gills. The change in LPO values in the gills of exposed fish was concentration- and time-dependent, showing significant increases (P<0.05 to <0.001) in all the exposed groups as compared with control fish. An almost similar pattern of LPO was observed in head kidney tissue (P<0.05 to <0.001). As regards liver, increase in LPO was not widespread, except at 0.5% for 90 days (P<0.05). In fact, reduced rates of LPO were observed in the livers of some groups. The results of respiratory burst corroborate with the phagocytic activation as well as with the extent of lipid peroxidation in the tissues, showing high population of circulatory phagocytes. Our results demonstrate that fish of polluted water are subjected to oxidative stress of multifarious dimensions. 相似文献
999.
Significant differences between the metabolism of retinoic acid by different tissues might be an important determinant of the effectiveness of a systemically administered inhibitor at a particular tissue site. Here the metabolism of retinoic acid has been studied in microsomal fractions from different tissues (liver, kidney, intestinal mucosa, lung, skin, brain) of the male rat to determine their relative metabolic activity. Kinetic analysis revealed major differences between the activity of different tissue microsomes. This is shown by the Vmax values for the metabolism of retinoic acid-liver (102+/-39.0 pmol (mg protein)(-1) min(-1)) was 100 times more active than the lung (1+/-0.03 pmol (mg protein)(-1) min(-1)), which was the least active. The range of Km values for microsomes from the different tissues was narrow (0.48-1.40 microM). Taking into account the mass of the tissue, the gross activity ranking for metabolism of retinoic acid was liver > skin = kidney > brain > intestinal mucosa > lung. It is concluded that metabolism of administered retinoic acid occurs mainly in the liver but that cellular retinoic acid levels in some other tissues (skin, kidney, brain) could be reduced (metabolized) to such an extent that higher levels might be observed after the use of inhibitors of retinoic acid metabolism. 相似文献
1000.
Sunil N Dutt Ahmad Haider-Ali Murray Stewart Simon M C Morrissey 《Indian journal of otolaryngology and head and neck surgery》1999,51(3):16-20
There are very few indications for surgical management of chronic rhinosinusitis in children. This has been partly due to the fact that the definition of what qualifies as racalcitrant sinusitis in children is still obscure. There is also significant evidence in literature that surgery, especially radical surgery, on the nose and sinuses in children would result in some interference with the growth of the facio-maxillary skeleton. The advent of Functional Endoscopie sino-nasal Surgery ( F. E. S. S. ) in recent years has changed the philosophy of surgery for paediatric rhinosinusitis and has proven to be an effective choice of management in difficult cases. We persent here our experience and preliminary results with the use of FESS in nine children with sinonasal disorders including cystic fibrosis. The usefulness of the recently described Lund- mackay and Kennedy Scoring System for chronic rhinosinusitis in terms of symptom score, radiological score, endoscopie score and surgical score has been demonstrated. 相似文献