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121.
Hybrid tumours are very rare salivary gland lesions composed of two or more different tumoural entities in a single neoplasm that arise within a definite topographical region. In most cases adenoid cystic carcinoma has been the predominant component in these lesions. In this study we describe two patients with hybrid tumours located in the palate, one in a 49-year-old woman and one in a 71-year-old man. The first case involved adenoid cystic carcinoma and mucoepidermoid carcinoma, and the patient in the second case exhibited adenoid cystic carcinoma and epithelial-myoepithelial carcinoma. Both patients were treated with surgery and radiotherapy, and there has been no evidence of recurrence after 13 and 36 months of follow-up, respectively. The recognition of the histologic component with the higher grade of malignancy in every case of hybrid tumour of the salivary glands is a necessary step to determine the biological behaviour and, consequently, to determine the proper therapeutic approach.  相似文献   
122.
After total gastrectomy, the ileocecal graft may act as a reservoir and protect against reflux but give rise to transposition of the ileum and cause possible changes in bile acid metabolism and nutrition. This study compared the ileocecal graft and jejunal pouch. Male Wistar rats weighing 265 +/- 22 g were submitted to sham operation (S), ileocecal interposition graft (IIG), and jejunal pouch interposition graft (JP) after total gastrectomy. Eight weeks later, the esophagus was examined for evidence of esophagitis. Nutritional biochemistry and weight profile were documented preoperatively and 8 weeks after surgery. The oral glucose tolerance test was performed. Thirty-three rats were operated on and 30 survived for 8 weeks. Esophagitis occurred in seven JP rats. Body weight was significantly higher in IIG than in JP rats (p < .05). Normal glucose tolerance to intragastric glucose load was observed in sham and operated rats. JP rats had a significant decrease in serum albumin, glucose, transferrin, hemoglobin, iron, folate, and calcium, compared to sham (p < .05). Cobalamine was significantly lower in IIG rats than in JP rats (p < .05). In the IIG and JP groups, serum/hepatic total bile acid did not differ significantly from preoperative and sham values. In conclusion, the IIG interposition graft in rats prevented esophagitis, preserved nutrition, and did not interfere with enterohepatic total bile acid circulation.  相似文献   
123.
124.
Catalase enzyme mutations and their association with diseases.   总被引:2,自引:0,他引:2  
Enzyme catalase seems to be the main regulator of hydrogen peroxide metabolism. Hydrogen peroxide at high concentrations is a toxic agent, while at low concentrations it appears to modulate some physiological processes such as signaling in cell proliferation, apoptosis, carbohydrate metabolism, and platelet activation. Benign catalase gene mutations of 5' noncoding region (15) and intron 1 (4) have no effect on catalase activity and are not associated with disease.Catalase gene mutations have been detected in association with diabetes mellitus, hypertension, and vitiligo. Decreases in catalase activity in patients with tumors is more likely to be due to decreased enzyme synthesis rather than to catalase mutations.Acatalasemia, the inherited deficiency of catalase has been detected in 11 countries. Its clinical features might be oral gangrene, altered lipid, carbohydrate, homocysteine metabolism and the increased risk of diabetes mellitus. The Japanese, Swiss, and Hungarian types of acatalasemia display differences in biochemical and genetic aspects. However, there are only limited reports on the syndrome causing these mutations.These data show that acatalasemia may be a syndrome with clinical, biochemical, genetic characteristics rather than just a simple enzyme deficiency.  相似文献   
125.
126.
The goal of this study was to evaluate the potential of albumin nanoparticles as a delivery system for antisense oligonucleotides. Nanoparticles were prepared by a coacervation process and cross-linkage with glutaraldehyde. Phosphodiester (PO) and phosphorotioate (PS) oligonucleotides were either adsorbed on the surface of nanoparticles (PO-NPA and PS-NPA) or incorporated in the nanoparticle matrix (PO-NPB and PS-NPB). When PO-loaded nanoparticles were incubated with phosphodiesterase, only NPB was able to keep the oligonucleotide hybridization capability for at least 60 min. The antiviral activity was evaluated in MRC-5 fibroblasts infected with human cytomegalovirus at a MOI of 0.0035. Both PO nanoparticle formulations significantly increased the antiviral activity of free PO (P<0.001) and NPB showed slightly higher efficacies than NPA (P<0.05). On the other hand, PS exhibited significant higher activity than free PO (P<0.001), however, no significant differences were found between PS-nanoparticle and PO-nanoparticle formulations. These findings were well correlated with the intracellular distribution observed for fluorescent oligonucleotide-loaded albumin nanoparticles. Even these carriers delayed and decreased the uptake of PO by MRC-5 cells, they finally induced a diffused cytoplasmic distribution and major nuclear accumulation. In summary, albumin nanoparticles partially protected a PO against enzymatic degradation and improved their presence in the nucleus and thus, increased its efficiency.  相似文献   
127.
As the capacity of the endogenous antioxidative system is limited, pharmacological treatment with antioxidants may help to protect neuronal tissue against increased amount of reactive oxygen species produced during oxidative stress. We attempted to improve resistance of rat hippocampal slices exposed to ischaemia in vitro (hypoxia (HYP) accompanied with decreased glucose concentration followed by reoxygenation (ROX)) and thus to diminish the impairment of synaptic transmission after HYP/ROX. We compared the protective features of the melatonin analogue 2,3-dihydromelatonin (2,3-DHM) with melatonin itself. In preliminary experiments, the compound 2,3-DHM compared to melatonin revealed enhanced antilipoperoxidation action in rat brain homogenates exposed to Fe/ascorbate system (-logIC(50) = 4.76 +/- 0.01 versus -logIC(50) = 2.51 +/- 0.02, respectively). In this study, 2,3-DHM (from 0.3 to 10 micromol l(-1)) applied at 30 min before the beginning of HYP and remaining all over the 6-min HYP as well as 20-min ROX, exerted a protective effect demonstrated by improvement of the population spike amplitude (PoS) recovery during ROX, with the maximum effect at 3 micromol l(-1). In accordance with this, the ratio of irreversibly damaged slices after HYP/ROX was decreased in the groups treated with 2,3-DHM. Moreover, a significant delay of PoS decay during HYP (expressed as half time, t(0.5)) was revealed at 2,3-DHM concentration 1 and 3 micromol l(-1)). An equipotent effect of melatonin and 2,3-DHM was achieved by a 100-times lower concentration of the latter (0.3 and 1 micromol l(-1)) compared to that of melatonin (30 and 100 micromol l(-1)). Further, compared to the highest effect of 2,3-DHM in the concentration 3 micromol l(-1) on the percentage of irreversibly damaged slices (only 20%), melatonin did not exert such pronounced effect, either in the concentration 30 or 100 micromol l(-1) (67 and 50%, respectively). We conclude that hydrogenation of the melatonin molecule significantly improved its antihypoxic effect in our model of rat hippocampal slices exposed to ischaemic conditions in vitro, similarly as it enhanced the antilipoperoxidation action of 2,3-DHM in our previous studies. These findings suggest that 2,3-DHM deserves more attention concerning its neuroprotective effect in oxidative stress-associated tissue damage.  相似文献   
128.
Platelets are cell fragments with dynamic properties involved in clot formation after tissue damage. Platelet activation causes a change in shape, secretion of intracellular granules and aggregation with each other through the cytoskeleton components and biochemical changes. Platelet adhesion, considered as the major event in haemostasis, has been studied in several in-vitro and in-vivo models to evaluate the feasible thrombogenicity of some materials, the dynamics of specific receptors, as well as the effect of different buffers and inhibitors in this process. In spite of the numerous reports about platelet activation, to date there is no information available about the fine structure of the platelet-platelet and platelet-substrate interactions. In the present report we describe an in-vitro system that allows the visualization of these interactions: platelets are adhered to an inert substrate, and interactions with suspended platelets as a process to initiate the formation of thrombi was followed by ultramicrotomy and transmission electron microscopy.  相似文献   
129.
AIM: The aim of this study was to quantify the flow-mediated dilatation (FMD) of brachial artery in asymptomatic members of families with familial combined hyperlipidemia (FCH) and to determine the relation between FMD and risk factors accompanying FCH. We also investigated the association between FMD and the intima-media thickness (IMT) of the common carotid artery. METHODS: Eighty-two members of 29 FCH families were divided into two groups: probands and hyperlipidemic first-degree relatives (HL) (n=47) and normolipidemic first-degree relatives (NL) (n=35). The control (C) groups, C-HL (n=20) and C-NL (n=20), consisted of sex- and age-matched healthy individuals. FMD was assessed in the brachial artery by measuring the change in brachial artery diameter in response to reactive hyperemia. RESULTS: Both hyperlipidemic subjects and their NL had significantly lower FMD (3.4+/-3% vs 6.3+/-2.8%, P<0.001, 5.2+/-2.3% vs 7.8+/-2.8%, P<0.01, respectively) compared to controls. In multivariate backward stepwise regression analysis, FMD in members of FCH families was independently associated with sex (P<0.001), age (P<0.01), C-peptide (P<0.05) and borderline with glycemia (P=0.052). FMD correlated inversely with IMT in all subjects of FCH families and in hyperlipidemic members. In multivariate backward stepwise regression analysis this relation remained independent (P<0.001, P<0.01, respectively). CONCLUSIONS: Members of FCH families showed impaired FMD, which was independently associated with markers of insulin resistance. FMD and IMT were independently associated in hyperlipidemic, but not in normolipidemic members of FCH families.  相似文献   
130.
A high-quality distance preserving output representation is provided to the neural gas (NG) network. The nonlinear mapping is determined concurrently along with the codebook vectors. The adaptation rule for codebook positions in the projection space minimizes a cost function that favors the trustworthy preservation of the local topology. The proposed visualization method, called OVI-NG, is an enhancement over curvilinear component analysis (CCA). The results show that the mapping quality obtained with OVI-NG outperforms the original CCA, in terms of the trustworthiness, continuity, topographic function and topology preservation measures.  相似文献   
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