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31.
Thirty patients with mild to moderate essential hypertension had received four weeks treatment with Lacidipine and serum lipid peroxide (LPO), superoxide dismutase (SOD) and insulin levels were measured before and after treatment. The results showed: (1) there were decreased in SOD activity and increased Lpo content the patients group (P < 0.01); (2) after treated with Lacidipine, the SOD acitvity increased and Lpo content decreased (P < 0.01); (3) Lacidipine had obvious antihypertensive effect with no significant changes in heart rate; (4) Lacidipine had no significant effects on insulin, blood glucose and lipids. The results suggest that lacidipine is a safe and effective antihypertensive agent and can improve the metabolic balances in free radical system. 相似文献
32.
EA Ismail IS Shabani M Badawi H Sanaa S Madi A Al-Tawari H Nadi M Zaki Q Al-saleh 《Canadian Metallurgical Quarterly》1998,13(10):488-492
We studied Guillain-Barré syndrome, affecting children 12 years old or less, throughout Kuwait, in the period between January 1, 1992, and March 31, 1997. Nineteen children had the diagnostic criteria of Guillain-Barré syndrome, with an overall annual incidence rate of 0.95/100,000 population at risk. Female patients outnumbered male patients with a sex ratio of 1.4:1. There was a clustering of cases in winter and spring and in the year 1996. The disease symptoms were relatively severe in our patients because only 16% (3 of 19) of them were able to walk at the height of their illness, whereas the rest were bed or chair bound or needed assisted ventilation. Two patients had the electrodiagnostic features of axonal neuropathy and both had residual deficits on follow-up, whereas the rest recovered fully. All the patients received intravenous immunoglobulin. The mean time to walk unaided was 23.5 days (range, 2-84 days) after intravenous immunoglobulin and excluding the two patients with axonal neuropathy, and full recovery was achieved in a mean time of 103 days (range, 30-300 days). Contrary to previous studies, we found no correlation between oral polio vaccine administration and Guillain-Barré syndrome in 2 successive years (1995 and 1996) during a nationwide campaign targeting children less than 5 years old. 相似文献
33.
We prospectively studied 63 children with transient hyperglycemia to determine their risk of acquiring insulin-dependent diabetes mellitus (IDDM) and to evaluate the predictive value of immunologic markers of prediabetes and of the intravenous glucose tolerance test. Children with transient hyperglycemia were identified by a prospective systematic review of the laboratory reports of a large children's hospital and an office-based pediatric practice and by referral from pediatricians. Transient hyperglycemia occurred in 0.46% of children seen in the children's hospital and in 0.013% of children attending a pediatric office practice. Insulin-dependent diabetes mellitus developed within 18 months of identification in 32% of children in whom transient hyperglycemia was discovered in the absence of a serious illness, compared with 2.3% of children identified during a serious illness (relative risk, 13.9; 95% confidence interval, 1.56 to 123.5). Islet cell antibodies and competitive insulin autoantibodies each had a 100% positive predictive value for IDDM; the negative predictive value of islet cell antibodies and competitive insulin autoantibodies was 96% and 98%, respectively. The stimulated insulin release during an intravenous glucose tolerance test, adjusted for age, had the highest overall accuracy of prediction. All children less than 6 years of age with stimulated insulin release levels < 85 pmol/L (12 microU/ml) subsequently had IDDM, as did an 11-year-old child whose stimulated insulin release level was below the 1st percentile of 170 pmol/L (24 microU/ml). To date, no child whose stimulated insulin release level was above the 5th percentile has had IDDM. We conclude that when transient hyperglycemia occurs during a serious intercurrent illness, the risk of progression to IDDM is low. In contrast, one third of children in whom transient hyperglycemia is identified without a serious illness can be expected to have IDDM within 1 year. A combination of islet cell antibodies, competitive insulin autoantibodies, and stimulated insulin release levels during an intravenous glucose tolerance test can accurately distinguish children with prediabetes from those with presumed benign transient increases in plasma glucose concentrations. 相似文献
34.
In order to cumpare the peformance of different supply diffuers of ventilation air, the airflow passern, temperature stratifiation and contaminant dispersion in a furnitured office ventilated by three kinds of air diffuer were numerically investigated. The air diffuers studied in this paper are a quarter-cylinder displacement diffuer on the floor and mixing diffuers (linear and vortex diffuers) on the ceiling. The heat sources in the of-fice are considered to be 50% convective and 50% radiative. The k-? two-equatwn model of turbulence is employed to predict the turbulent diffusion. The results show that the displacement diffuser provides a rather uniform flow field with low velocify in most areas, and the vertical temperature difference from floor to ceiling is as high as 6 K. With the linear diffuser, the air velociry is high, and the temperature is uniform both horizontally and vertically. The air velocity generated by the vortex diffuser is moderate. The distributions of the temperature and the contaminant are rather uniform. 相似文献
35.
Prostaglandin A2 (PGA2) potently inhibits cell proliferation and suppresses tumor growth in vivo, but little is known regarding the molecular mechanisms mediating these effects. Here we demonstrate that treatment of breast carcinoma MCF-7 cells with PGA2 leads to G1 arrest associated with a dramatic decrease in the levels of cyclin D1 and cyclin-dependent kinase 4 (cdk4) and accompanied by an increase in the expression of p21. We further show that these effects occur independent of cellular p53 status. The decline in cyclin D and cdk4 protein levels is correlated with loss in cdk4 kinase activity, cdk2 activity is also significantly inhibited in PGA2-treated cells, an effect closely associated with the upregulation of p21. Immunoprecipitation experiments verified that p21 was indeed complexed with cdk2 in PGA2-treated cells. Additional experiments with synchronized MCF-7 cultures stimulated with serum revealed that treatment with PGA2 prevents the progression of cells from G1 to S. Accordingly, the kinase activity associated with cdk4, cyclin E, and cdk2 immunocomplexes, which normally increases following serum addition, was unchanged in PGA2-treated cells. Furthermore, the retinoblastoma protein (Rb), a substrate of cdk4 and cdk2 whose phosphorylation is necessary for cell cycle progression, remains underphosphorylated in PGA2-treated serum-stimulated cells. These findings indicate that PGA2 exerts its growth-inhibitory effects through modulation of the expression and/or activity of several key G1 regulatory proteins. Our results highlight the chemotherapeutic potential of PGA2, particularly for suppressing growth of tumors lacking p53 function. 相似文献
36.
Q Hu M Trevisan Y Xu W Dong SA Berger SD Lyman MD Minden 《Canadian Metallurgical Quarterly》1995,95(6):2530-2538
The growth of human leukemic cells in culture and in vivo is dependent upon the presence of hematopoietic growth factors. Most populations of human leukemic acute myeloblastic leukemia (AML) cells express c-Kit on their surface and respond to Kit ligand (KL) in culture. To determine if this interaction was of potential significance in vivo we used a mouse model system. 32D cells, a murine IL-3-dependent myeloid cell line, were rendered KL responsive by transfection of the murine c-Kit. After injection of 32D or 32D-Kit cells into syngeneic hosts, animals bearing 32D-Kit cells, but not 32D cells, became moribund and were killed. These animals had circulating leukemic blast cells, infiltration of bone marrow, spleen, brain, liver, lung, and kidney. Cells recovered from some of the animals continued to be dependent upon IL-3 or KL for growth while in other cases the cells were factor independent. This model illustrates that the constitutive expression of c-Kit enhances the leukemic potential of 32D cells. The model will be useful for studying the progression of leukemia in vivo and testing whether interruption of the interaction of Kit and KL can affect the growth of leukemic cells. 相似文献
37.
The problem of joint estimation of time delay and Doppler shift is considered from the point of view of the Wigner distribution of the signal. A very efficient method of obtaining the optimum signal with minimum estimation error based on the convexity of the design region is developed. Practical applications, however, require the signal to satisfy other constraints which present complications in acquiring the optimum signal. A design approach based on the method of simulated annealing is suggested to solve for the optimum signal under constraints. The performance of the signals so obtained is evaluated and compared with that of signals obtained by synthesis 相似文献
38.
Preparation of Metal-Coated Carbon Fiber Reinforced Composites and Their Electromagnetic Properties 总被引:1,自引:0,他引:1
Medium temperature curing by infrared radiation was used to prepare electromagnetic wave absorbing multilayered plastic matrix composite materials containing metal-coated carbon fibers (MCFs). The electromagnetic properties of the materials were investigated by frequency scanning tests with microwave vector network analyzer. It is found that the electromagnetic parameters, mainly permittivity of the composites increase significantly with the addition of MCFs, which gives the composites good designability as thin, light-weight EM wave absorbers. It is also shown that MCFs can improve on the EM wave energy attenuating property of the composites by widening the work frequency band width and raising the absorptive peak 相似文献
39.
Goni O. Hossain F. Yusuf S.U. Rahman M. Kaneko E. Takahashi H. 《Power Delivery, IEEE Transactions on》2006,21(4):1778-1786
Simulation of very fast surge phenomena in a three-dimensional (3-D) structure requires a method based on Maxwell's equations, such as the finite-difference time-domain (FDTD) method or the method of moments, because circuit-equation-based methods cannot handle the phenomena. This paper uses a method of thin-wire representation of the vertical conductor system for the FDTD method which is suitable for the 3-D surge simulation. The thin-wire representation is indispensable to simulate electromagnetic surges on wires or steel frames in which the radius is smaller than a discretized space step used in the FDTD simulation. In this paper, a general surge analysis program named the virtual surge test lab based on the Maxwell's equations formulated by the FDTD method, is used to simulate the surge phenomena of a vertical conductor, including the effects of horizontal wave incidence and vertical wave incidence. Experimental results on the reduced scale model have been presented in order to compare among the simulation results by the FDTD method and the results using numerical electromagnetic code based on the MoM. 相似文献
40.
In industrial systems, the formation of biofilms can cause many problems, such as an increase in the flow resistance of pipelines, energy losses in fluid transport and heat exchangers, product contamination, materials deterioration, and biocorrosion. As a result, biofilms contribute substantially to economic losses in the industry. Corrosion is particularly an issue in the petroleum industry and its implications range from down-hole completion through petroleum processing units. Much of this corrosion is attributed to microbial activities. This paper proposes a mathematical model for predicting substrate concentration for such microbial growth. Substrate concentrations in the system and near the biofilm surface are one of the parameters that has a great effect in determining the extent of the problems associated with biofilms. In this study, a convective-diffusion model under various flow conditions (stagnant, laminar, and turbulent) has been solved using the finite difference technique, employing the alternating direction implicit (ADI) method. The model assumes that a liquid containing substrate and bacteria is flowing in a pipeline with known concentrations at the inlet and then predicts the variation of the transient (as a function of time) substrate concentration along the pipeline and as a function of the pipe radius. The model is then used to predict and estimate the substrate concentration profiles on the biofilm surface under different environmental conditions. A parametric study was also conducted to study the effect of the different parameters influencing the substrate concentration profiles in the system and on the biofilm surface. 相似文献