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1.
Polyclonal antibodies raised against purified and urea-denatured double-stranded protein kinase (PKR) from human origin cross-reacted by immunoblotting with a 48-kD protein (p48) induced by the three types of interferon (IFN), alpha, beta, and gamma. The induction of p48 is IFN dose dependent and its accumulation occurs a few hours after the addition of IFN. The induction of p48 is blocked by actinomycin D. Analysis by two-dimensional gel isoelectric-focusing, revealed p48 as a single spot with an isoelectric point (pI) of 6.8. In the same experiment the PKR was revealed as several subspecies with pI values in the pH range of 7.4-8.0. Cell fractionation experiments indicated that PKR and p48 have different subcellular localizations: PKR was found to be associated with the microsomal pellet as shown previously whereas p48 was recovered in the microsomal supernatant fraction. In addition to these differences, PKR and p48 were found to be differentially expressed in some human cells treated with the three types of IFN. For example, in HeLa cells, IFN-alpha or IFN-beta induced similarly both PKR and p48 whereas IFN-gamma induced mainly p48. In U937 cells in which PKR was not expressed with or without IFN treatment, p48 was strongly induced by all three types of IFN. These results suggest different mechanisms for the induction of PKR and p48. In view of its presence in different types of human cells and its induction by different types of IFN, it is possible to suggest that p48 might play an important role in mediating some of the action of IFN.  相似文献   

2.
The biochemical basis for the functional heterogeneity of human blood platelets was investigated in terms of protein phosphorylation, cytoplasmic calcium ([Ca2+]i), the ratio of 46 and 50 kDa vasodilator-stimulated protein (VASP), and GTP-binding proteins (G-proteins). Platelets were fractionated by density. Comparing resting low-density platelets (LDP) to high-density platelets (HDP) revealed higher phosphorylation of proteins in the 47, 31, and 24 kDa ranges. A higher phosphorylation of the 20 kDa protein in LDP compared to HDP was related to an enhanced [Ca2+]i, an increased ADP-ribosylation of the inhibitory G-protein (G(i alpha1-3)) and rhoA, and a decreased ADP-ribosylation of the stimulatory G-protein (G(s alpha)). The differences in the ribosylation patterns of the subpopulations were not influenced by thrombin stimulation or exposure to prostaglandin E1 (PGE1). An 18 kDa phosphoprotein was more highly phosphorylated in resting HDP than in LDP. Thrombin exposure caused dephosphorylation of the 18 kDa phosphoprotein in the HDP, but generally increased phosphorylation of both HDP and LDP in the 47, 31, 24, and 20 kDa bands. Preincubation with prostaglandin E1 or sodium nitroprusside diminished the subsequent thrombin-induced increase in phosphorylation, particularly in HDP. In unstimulated HDP, the 50 kDa VASP phospho form was enhanced, whereas in unstimulated LDP the 46 kDa VASP dephospho form was increased. Our findings suggest that the functional heterogeneity of platelets is partly derived from differences in signal transduction mechanisms reflected in varying phosphoprotein patterns and G-protein properties of platelet stimulatory and inhibitory pathways.  相似文献   

3.
Bronchoalveolar lavage (BAL) was performed at weekly intervals in 10 Thoroughbred horses in race training (group 1) and in 4 rested horses (group 2) for 10 weeks. Lavages were continued on a weekly basis in 4 group 1 horses for an additional 9 weeks (group 3). Cytological analysis of samples included leukocyte counts, erythrocyte counts, differential leukocyte counts, and haemosiderophage score. The mean leukocyte concentration was significantly lower in group 1 (92.1 +/- 4.6 cells/microL) when compared with group 2 (133.5 +/- 8.2 cells/microL), P = 0.037. The differential leukocyte data were not significantly different between groups. There was a large amount of variability in the percentage of macrophages and lymphocytes in the differential counts over time with no obvious trends. The proportion of neutrophils demonstrated a tendency to decrease over time for both groups 1 and 2. Erythrocyte counts and haemosiderin scores were significantly higher in the exercising group than the rested horses. Neither exercise nor the technique itself evoked an inflammatory response in the BAL fluid.  相似文献   

4.
The hepatotoxicity of acetaminophen overdose depends on the metabolic activation to a toxic reactive metabolite by the hepatic mixed function oxidases. There is evidence that an increase in cytosolic Ca2+ is involved in acetaminophen hepatotoxicity. The effects of the Ca2+-antagonists nifedipine (NF), verapamil (V), diltiazem (DL) and of the calmodulin antagonist trifluoperazine (TFP) on the activity of some drug-metabolizing enzyme systems, lipid peroxidation and acute acetaminophen toxicity were studied in male albino mice. No changes in the drug-metabolizing enzyme activities studied and in the cytochrome P-450 and b5 contents were observed 1 h after oral administration of V (20 mg/kg). DL (70 mg/kg) and TFP (3 mg/kg). NF (50 mg/kg) increased cytochrome P-450 content, NADPH-cytochrome c reductase and ethylmorphine-N-demethylase activities. DL and TFP significantly decreased lipid peroxidation. NF, V, DL and TFP administered 1 h before acetaminophen (700 mg/kg orally) increased the mean survival time of animals. A large increase of serum aspartate aminotransferase(AST), and liver weight and depletion of liver reduced glutathione (GSH) occurred in animals receiving toxic acetaminophen dose. NF, V and DL prevented and TFP decreased the acetaminophen-induced hepatic damage measured both by plasma AST and by liver weight. NF, V, DL and TFP changed neither the hepatic GSH level nor the GSH depletion provoked by the toxic dose of acetaminophen. This suggests that V, DL and TFP do not influence the amount of the acetaminophen toxic metabolite formed in the liver. The possible mechanism of the protective effect of NF, V, DL and TFP on the acetaminophen-induced toxicity is discussed.  相似文献   

5.
OBJECTIVE: To evaluate the contribution of bronchoalveolar lavage (BAL) and bronchial brushing (BB) and the use of different tinctorial stains in the detection of Pneumocystis carinii (PC) in human immunodeficiency virus (HIV)-positive patients. STUDY DESIGN: In a retrospective study, 195 HIV-positive patients suspected of a pulmonary infection underwent bronchoscopy with BAL. In 143 cases subsequent BB was performed. On 135 BAL fluid cytocentrifuge preparations four staining techniques were applied simultaneously: May-Grünwald-Giemsa (MGG), toluidine blue-O (TOL), Papani-colaou (PAP) and Grocott methenamine silver (GRO). RESULTS: PC was recovered in 79 (40.5%) cases. The yields of MGG and TOL were identical (33.3%). PAP and GRO showed lower results, 31.1% and 29.6%, respectively. These differences were not statistically significant. The combination of BAL and BB revealed 64 cases of PC infection. BAL was positive in the vast majority of cases (63, 44.1%). BB was positive in 54 (37.8%). The combination of positive BB with negative BAL was present in one case. However, 10 cases of PC were found with the use of BAL and not detected by BB (P < .01). CONCLUSION: The results of this study indicate that to confirm a PC infection in HIV-positive patients, the use of bronchoalveolar lavage with a single staining technique is appropriate. Bronchial brushing seems to be of limited additional value.  相似文献   

6.
As collections of lower respiratory tract specimens from young children with cystic fibrosis (CF) are difficult, we determined whether oropharyngeal cultures predicted lower airway pathogens. During 1992-1994, 75 of 90 (83%) infants with CF diagnosed by neonatal screening had 150 simultaneous bronchoalveolar lavage (BAL) and oropharyngeal specimens collected for quantitative bacterial culture at a mean age of 17 months (range, 1-52). Ten children undergoing bronchoscopy for stridor served as controls. Total and differential cell counts and interleukin-8 concentrations were measured in BAL fluid. A subset of bacterial pathogens were typed by pulsed field gel electrophoresis. A non-linear relationship with inflammatory markers supported a diagnosis of lower airway infection when > or = 10(5) colony-forming units/ml were detected. This criterion was met in 47 (31%) BAL cultures from 37 (49%) children. Staphylococcus aureus (19%), Pseudomonas aeruginosa (11%), and Hemophilus influenzae (8%) were the major lower airway pathogens. In oropharyngeal cultures, S. aureus (47%), Escherichia coli (23%), H. influenzae (15%), and P. aeruginosa (13%) predominated. The sensitivity, specificity, and positive and negative predictive values of oropharyngeal cultures for pathogens causing lower respiratory infections were 82%, 83%, 41%, and 97%, respectively. When there was agreement between paired oropharyngeal and BAL cultures, genetic fingerprinting showed some strains of the same organism were unrelated. We conclude that oropharyngeal cultures do not reliably predict the presence of bacterial pathogens in the lower airways of young CF children.  相似文献   

7.
8.
Obliterative bronchiolitis (OB) is a devastating complication in lung transplantation. We postulated that the pathogenesis of OB is mediated, in part, by neutrophils. We serially collected bronchoalveolar lavage (BAL) fluid from lung transplant recipients. Patients were divided into two groups depending on the presence or absence of OB. Samples from patients who never developed OB were further divided according to whether rejection was present. These samples were labeled healthy or rejection. Samples from patients who developed OB were divided according to whether the sample was obtained before (future OB) or at the time of diagnosis of OB (OB). The OB group, as compared with the healthy and rejection group, had significantly elevated neutrophil counts (3.9 x 10(5) +/- 1.8 x 10(5) vs 0.3 x 10(5) +/- 0.07 x 10(5) and 0.4 x 10(5) +/- 0.1 x 10(5), respectively, p < 0.01 for both) and levels of IL-8 (3131 +/- 1468 pg/ml vs 240 +/- 62 pg/ml and 172 +/- 47 pg/ml, p < 0.01 for both). Furthermore, we demonstrated immunolocalization of IL-8 associated with alpha smooth muscle actin-positive cells in the peribronchial region of OB. To confirm that the IL-8 present in BAL fluid from patients with OB was bioactive, we performed neutrophil chemotaxis experiments that showed that IL-8 accounted for a significant amount of the neutrophil chemotactic activity. We also found a trend toward higher levels of neutrophils and IL-8 in BALs from the future OB as compared with the healthy group (7.1 x 10(4) +/- 4.2 x 10(4) vs 3.4 x 10(4) +/- 0.7 x 10(4) and 500 +/- 306 pg/ml vs 240 +/- 62 pg/ml). In conclusion, we have provided the novel observation that in lung transplant recipients with OB, neutrophilia is present and highly correlated with the presence of IL-8.  相似文献   

9.
There are clinically different types of eosinophilic pneumonia (EP) but no study to date has compared pulmonary inflammatory cells between different types of EP, such as acute eosinophilic pneumonia (AEP), chronic eosinophilic pneumonia (CEP) and drug-induced eosinophilic pneumonia (drug-EP). The present study compared bronchoalveolar lavage fluid (BALF) cell findings to elucidate whether the profiles of the pulmonary inflammatory cells were different among the three types of EP. Clinical records of 28 patients with EP, consisting of eight AEP patients, 10 CEP patients and 10 drug-EP patients, were examined retrospectively. The differential cell counts, the CD4+/CD8+ ratio of lymphocytes, the percentage of HLA-DR+ in CD4+ and CD8+ lymphocytes, and the mean number of nuclear segmentations in cosinophils in BALF were compared among the three types of EP. The numbers of total cells, lymphocytes, neutrophils and eosinophils in BALF from patients with AEP were increased compared with those from normal subjects, and patients with CEP and drug-EP. The CD4+/CD8+ ratio of the BALF lymphocytes in patients with AEP, which exceeded 1.0 in all patients, was significantly higher than that in normal subjects. The percentages of HLA-DR+ cells in CD8+ lymphocytes in BALF from patients with CEP were significantly higher than those from patients with AEP and drug-EP. There was no significant difference in the mean number of nuclear segmentations in eosinophils in BALF among the three types of EP. The BALF cell findings in patients with EP showed some characteristics in accordance with type of EP. It is suggested that pulmonary neutrophils and lymphocytes, rather than eosinophils, may be related to the pathogenesis of the different types of EP.  相似文献   

10.
The authors show that intensification of peloid therapy, i.e. more frequent procedures, in patients with pulmonary diseases imposes additional load on the regulatory systems: vegetative, cardiovascular, immune. Moderate balneological reactions become more frequent, therapeutic results worsen. How to correct the above negative effects is proposed.  相似文献   

11.
12.
文章论述优质合金模具铜新标准的颁发必要性及迫切性,新标准的技术指标,先进之处及执行新标准的工艺要素。执行新标准的同时,必须重视钢材表面质量,重视钢厂与客户之间的供需关系、重视市场需求的性能更优的特色模具钢的技术开发。  相似文献   

13.
文章论述优质合金模具钢新标准的颁发必要性及迫切性,新标准的技术指标,先进之处及执行新标准的工艺要素。执行新标准的同时,必须重视钢材表面质量,重视钢厂与客户之间的供需关系、重视市场需求的性能更优的特色模具钢的技术开发。  相似文献   

14.
PURPOSE: The aim of our study was to evaluate a new fluorocarbon (Teflon AF), used as a coating of poly-methylmethacrylate intraocular lenses. Teflon AF can be dissolved in special solvents (liquid fluorocarbons). It is the first amorphous and transparent form of teflon. MATERIALS AND METHODS: The coating was performed and the surface quality of the teflon-coated lenses was evaluated by scanning electron microscopy. Twenty teflon-coated and 10 uncoated lenses were implanted in rabbit eyes after phacoemulsification. They were compared concerning the presence of iris-lens synechias and the number of deposits on the lens' surfaces. An in vitro static touch model was used to compare endothelial damage produced by the 2 kinds of intraocular lenses. The results from this model were quantitatively analyzed, using the BIOCOM 200 image-processing system. RESULTS: The teflon group had no iris-lens synechias and the control group had 2 extensive synechias. There were significantly fewer deposits on the surfaces of teflon-coated lenses on days 30 and 60 post-operatively (P < 0.0001) than on the control lenses. Teflon-coated lenses produced significantly less endothelial damage than did control lenses (P < 0.0001). CONCLUSIONS: Teflon AF presents an anti-adhesive effect that increases the biocompatibility of polymethylmethacrylate lenses and reduces endothelial damage during their intraocular insertion.  相似文献   

15.
16.
尚户明 《四川冶金》2003,25(2):46-48
本文通过分析钢包底部用耐火材料的损毁机理,研制出以特级矾土、烧结尖晶石和中挡烧结镁砂为主要原料,采用超细粉凝聚结合的新型铝镁浇注料。  相似文献   

17.
18.
一种新型半金属刹车片材料的研究   总被引:1,自引:0,他引:1  
研究了加有莱武氏相强化的铁基抗磨合金细粉末、纳米级丁腈橡胶粉、纳米级Al2O3和BN、促进剂DPTT和DMTD等组分的无石棉刹车片材料,试样通过了XD-MSM机定速试验和Chase机试验.结果表明:定速试验的磨损率较低,摩擦稳度αst在0.84以上;Chase试验表明,300℃的高温摩擦系数达0.428~0.497,热衰退很小,其摩擦稳度αst更强,多数在0.92以上,甚至于达到0.998;用此材料制成的产品试运行情况良好.文章分析了添加的合金粉末和纳米级丁腈橡胶粉的作用机理,指出了合金莱武氏相金属互化物的原子键合和特殊的晶体结构对高的高温摩擦系数和稳度αst、低的热衰退和粘着磨损所起的关键作用;纳米级丁腈橡胶粉韧化基体,与其它添加剂优化组合,对减少磨损、提高稳度αst、防止噪音起重要作用.  相似文献   

19.
新型低膨胀Mo-Cu合金电子封接材料研究   总被引:1,自引:0,他引:1  
本试验研究了添加活化元素Ni对Mo-Cu合金的相对密度、烧结性能、热导率、电导率、热膨胀系数及组织的影响.研究结果表明:在Mo-Cu合金中加入Ni能降低合金烧结的致密化温度,促进烧结的进行.但Ni的加入降低了合金的导电和导热性能,并且使合金的组织变得粗大,75Mo-20Cu-5Ni的导热系数和95%Al2O3,陶瓷非常匹配,可被用作与其封接的合金.  相似文献   

20.
新型无银触头材料的研制   总被引:2,自引:0,他引:2  
采用粉末冶金技术研制了一种新型无银触头材料。该材料的综合性能,如密度、硬度、电阻率、灭弧特性及温度特性与传统的银基触头材料接近。所研制的无银触头在许多应用中,如在电力机车上可替代银基材料,具有明显的经济效益和社会效益。  相似文献   

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