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421.
422.
Steven J Lavine 《Cardiovascular ultrasound》2006,4(1):1-8
Background
Carotid plaque severity and morphology can affect cardiovascular prognosis. We evaluate both the importance of echographically assessed carotid artery plaque geometry and morphology as predictors of death in hospitalised cardiological patients.Methods
541 hospitalised patients admitted in a cardiological division (age = 66 ± 11 years, 411 men), have been studied through ultrasound Duplex carotid scan and successively followed-up for a median of 34 months. Echo evaluation assessed plaque severity and morphology (presence of heterogeneity and profile).Results
361 patients showed carotid stenosis (67% with <50% stenosis, 18% with 50–69% stenosis, 9% with >70% stenosis, 4% with near occlusion and 2% with total occlusion). During the follow-up period, there were 83 all-cause deaths (15% of the total population). Using Cox's proportional hazard model, age (RR 1.06, 95% CI 1.03–1.09, p = 0.000), ejection fraction > 50% (RR = 0.62, 95% CI 0.4–0.96, p = 0.03), treatment with statins (RR = 0.52, 95% CI 0.29–0.95, p = 0.34) and the presence of a heterogeneous plaque (RR 1.6; 95% CI, 1.2 to 2.14, p = 0.002) were independent predictors of death. Kaplan – Meier survival estimates have shown the best outcome in patients without plaque, intermediate in patients with homogeneous plaques and the worst outcome in patients with heterogeneous plaques (90% vs 79% vs 73%, p = 0.0001).Conclusion
In hospitalised cardiological patients, carotid plaque presence and morphology assessed by ultrasound are independent predictors of death. 相似文献423.
Shao ZH Hsu CW Chang WT Waypa GB Li J Li D Li CQ Anderson T Qin Y Schumacker PT Becker LB Hoek TL 《Cell biology and toxicology》2006,22(3):149-158
Grape seed proanthocyanidin extract (GPSE) at high doses has been shown to exhibit cytotoxicity that is associated with increased
apoptotic cell death. Nitric oxide (NO), being a regulator of apoptosis, can be increased in production by the administration
of GSPE. In a chick cardiomyocyte study, we demonstrated that high-dose (500 μg/ml) GSPE produces a significantly high level
of NO that contributes to increased apoptotic cell death detected by propidium iodide and terminal deoxynucleotidyl transferase-mediated
dUTP nick-end labeling (TUNEL) staining. It is also associated with the depletion of intracellular glutathione (GSH), probably
due to increased consumption by NO with the formation of S-nitrosoglutathione. Co-treatment with L-NAME, a NO synthase inhibitor, results in reduction of NO and apoptotic cell death.
The decline in reduced GSH/oxidized GSH (GSSG) ratio is also reversed. N-Acetylcysteine, a thiol compound that reacts directly with NO, can reduce the increased NO generation and reverse the decreased
GSH/GSSG ratio, thereby attenuating the cytotoxicity induced by high-dose GSPE. Taken together, these results suggest that
endogenous NO synthase (NOS) activation and excessive NO production play a key role in the pathogenesis of high-dose GSPE-induced
cytotoxicity. 相似文献
424.
425.
The mutation rates of di-, tri- and tetranucleotide repeats in Drosophila melanogaster 总被引:3,自引:1,他引:3
Schug MD; Hutter CM; Wetterstrand KA; Gaudette MS; Mackay TF; Aquadro CF 《Molecular biology and evolution》1998,15(12):1751-1760
In a recent study, we reported that the combined average mutation rate of
10 di-, 6 tri-, and 8 tetranucleotide repeats in Drosophila melanogaster
was 6.3 x 10(-6) mutations per locus per generation, a rate substantially
below that of microsatellite repeat units in mammals studied to date (range
= 10(-2)-10(-5) per locus per generation). To obtain a more precise
estimate of mutation rate for dinucleotide repeat motifs alone, we assayed
39 new dinucleotide repeat microsatellite loci in the mutation accumulation
lines from our earlier study. Our estimate of mutation rate for a total of
49 dinucleotide repeats is 9.3 x 10(-6) per locus per generation, only
slightly higher than the estimate from our earlier study. We also estimated
the relative difference in microsatellite mutation rate among di-, tri-,
and tetranucleotide repeats in the genome of D. melanogaster using a method
based on population variation, and we found that tri- and tetranucleotide
repeats mutate at rates 6.4 and 8.4 times slower than that of dinucleotide
repeats, respectively. The slower mutation rates of tri- and
tetranucleotide repeats appear to be associated with a relatively short
repeat unit length of these repeat motifs in the genome of D. melanogaster.
A positive correlation between repeat unit length and allelic variation
suggests that mutation rate increases as the repeat unit lengths of
microsatellites increase.
相似文献
426.
Summary The morphology of the uterine microvasculature during early placentation was investigated by light microscopy, scanning electron microscopy of microvascular corrosion casts and transmission electron microscopy in rats 26 and 50 h after initiation of implantation. Increased vascular permeability at implantation sites was observed as a positive blue-dye test, spacing of vessels, and as localized extravasations of resin from postcapillary venules in the center of the endometrium. The subepithelial capillary plexus in the primary decidual zone adjacent to the blastocyst was shut down 50 h after initiation of implantation, most probably due to swelling of the metabolically activated endothelium and volume expansion of the decidual cells. This phenomenon coincided with the mesometrial orientation of the inner cell mass of the blastocyst; it may be a uterine mechanism to direct the ectoplacental cone toward the patent vessels in the mesometrial portion of the uterus. The remaining vessels at implantation sites were generally fewer, larger in diameter, more irregular in caliber, and more uniformly oriented along the implantation axis than their counterparts at inter-implantation sites. No vascular sprouts were observed during the interval studied. 相似文献
427.
Summary Expression of the galactokinase gene in Tetrahymena thermophila can be repressed by glucose, glucose analogs, and epinephrine, each apparently acting through increased intracellular levels
of adenosine 3′:5′-cyc lic monophosphate (cAMP) (1). To characterize further the initial steps in the control of galactokinase
gene-expression by glucose, we have analyzed mutants which are defective in the metabolism of this sugar; these mutants were
selected for their resistance to the glucose analog, 2-deoxyglucose (2). In one such mutant that is deficient in glucokinase,
the synthesis of galactokinase is totally resistant to repression by glucose or its analogs, while repression by exogenous
catecholamines or dibutyryl cAMP is unaffected. Radiochromatographic analyses of extracts of wild-type cells incubated with
[14C]-deoxyglucose reveal intracellular conversio to several deoxyglucose metabolites, principally deoxyglucose-6-P and smaller
amounts of deoxyglunose 1-P and 2-deoxygluconate; extracts of glucokinase-deficient cells prepared in a similar manner contain
only trace amounts of deoxyglucose-6-P. The glucose analog 3-O-methylglucose, which is transported but not phosphorylated
in wild-type cells, also cannot maintain repression of galactokinase. These results establish that the transport and subsequent
phosphorylation of glucose are required for glucose-initiated repression of galactokinase gene expression, possibly acting
by modulation of catecholamine or cyclic AMP levels.
Additionally, we show unequivocally that: (a) cells containing derepressed levels of galactokinase are repressed upon the
addition of glucose by inhibition of the synthesis of new enzyme and dilution of preformed enzyme concomitant with cell division,
rather than through selective inactivation or degradation of galactokinase; and (b) glycerol kinase, glucokinase and fructokinase
activities also are repressed by glucose in wild-type Tetrahymena, indicating that the glucose repression phenomenon is pleiotropic. Because the glucose repression of the synthesis of each
of these enzymes is abolished in cells deficient in glucokinase, the regulatory mechanisms elucidated for repression of galactokinase
synthesis are likely to be of wide significance. 相似文献
428.
Background ERCP-directed brush cytology is used to sample lesions of the pancreatic and biliary ducts and the ampulla of Vater. With conventional preparations, the sensitivity and specificity range from 44% to 63% and 80% to 98%, respectively, and increased N : C ratio, nuclear molding and loss of honeycombing are reliable features of malignancy. The performance and morphology of specimens prepared by ThinPrep, a liquid-based cytology technique is mostly unknown.
Methods The laboratory information system was searched for all cases prepared by ThinPrep. Patient disease classification of benign or malignant was determined by linkage with the provincial cancer registry and was the gold standard against which sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were calculated. True positives and negatives were reviewed to identify predictive cytomorphologic features.
Results Between 1996 and 2001, there were 149 ThinPrep specimens; 55 (37%) were reported as positive for malignancy and 94 (63%) as negative. Disease was classified as malignant in 86 (58%) patients and benign in 63 (42%). There were 42 false negative, 11 false positive, 52 true negative, and 44 true positive cytology results. Sensitivity was 51.2% (CI; 40.2 : 62.0), specificity 82.5% (CI; 70.5 : 90.6), and PPV and NPV 80.0% (CI; 66.6 : 89) and 55.3% (CI; 44.7 : 65.5), respectively. Cell groups with crowded, enlarged, irregular nuclei and nuclear features of vesicular chromatin and large, multiple irregular nucleoli correlated with malignant disease, while monolayered sheets of uniform columnar cells, regular nuclei and a finely granular chromatin correlated with benign disease.
Conclusions The performance of ThinPrep brushings from this anatomic site equals conventional preparations. Cytomorphologic features of malignancy are more frequent and pronounced with ThinPrep. 相似文献
Methods The laboratory information system was searched for all cases prepared by ThinPrep. Patient disease classification of benign or malignant was determined by linkage with the provincial cancer registry and was the gold standard against which sensitivity, specificity, positive (PPV) and negative predictive values (NPV) were calculated. True positives and negatives were reviewed to identify predictive cytomorphologic features.
Results Between 1996 and 2001, there were 149 ThinPrep specimens; 55 (37%) were reported as positive for malignancy and 94 (63%) as negative. Disease was classified as malignant in 86 (58%) patients and benign in 63 (42%). There were 42 false negative, 11 false positive, 52 true negative, and 44 true positive cytology results. Sensitivity was 51.2% (CI; 40.2 : 62.0), specificity 82.5% (CI; 70.5 : 90.6), and PPV and NPV 80.0% (CI; 66.6 : 89) and 55.3% (CI; 44.7 : 65.5), respectively. Cell groups with crowded, enlarged, irregular nuclei and nuclear features of vesicular chromatin and large, multiple irregular nucleoli correlated with malignant disease, while monolayered sheets of uniform columnar cells, regular nuclei and a finely granular chromatin correlated with benign disease.
Conclusions The performance of ThinPrep brushings from this anatomic site equals conventional preparations. Cytomorphologic features of malignancy are more frequent and pronounced with ThinPrep. 相似文献
429.
Biofloc Technology: Emerging Microbial Biotechnology for the Improvement of Aquaculture Productivity
MAMDOH T. JAMAL MOHAMMED BROOM BANDAR A. AL-MUR MAMDOUH AL HARBI MOHAMMED GHANDOURAH AHMED AL OTAIBI MD FAZLUL HAQUE 《Polish journal of microbiology》2020,69(4):401
With the significant increases in the human population, global aquaculture has undergone a great increase during the last decade. The management of optimum conditions for fish production, which are entirely based on the physicochemical and biological qualities of water, plays a vital role in the prompt aquaculture growth. Therefore, focusing on research that highlights the understanding of water quality and breeding systems’ stability is very important. The biofloc technology (BFT) is a system that maximizes aquaculture productivity by using microbial biotechnology to increase the efficacy and utilization of fish feeds, where toxic materials such as nitrogen components are treated and converted to a useful product, like a protein for using as supplementary feeds to the fish and crustaceans. Thus, biofloc is an excellent technology used to develop the aquaculture system under limited or zero water exchange with high fish stocking density, strong aeration, and biota. This review is highlighted on biofloc composition and mechanism of system work, especially the optimization of water quality and treatment of ammonium wastes. In addition, the advantages and disadvantages of the BFT system have been explained. Finally, the importance of contemporary research on biofloc systems as a figure of microbial biotechnology has been emphasized with arguments for developing this system for better production of aquaculture with limited natural resources of water.Key words: biofloc, BFT, aquaculture, microbes, water quality, wastes 相似文献
430.
Three naphthalene-degrading strains were isolated from compost, characterized by morphological and physiological properties and differentiated by 16S rDNA RFLP. During growth on naphthalene, Pseudomonas aeruginosa 2NR produced ortho catechol pathway intermediates and gentisic acid. The ability to accumulate and degrade gentisic acid shows that Ps. aeruginosa 2NR has a different salicylate pathway to that of the intensely studied Ps. putida NCIB 9816. Molecular analysis showed the presence both of genes of the upper naphthalene pathway and genes of the ortho and meta catechol pathways. The insertion of nagH and nagG, coding for salicylate 5-hydroxylase in Pseudomonas sp. U2, was absent in Ps. aeruginosa 2NR, as in Ps. putida NCIMB 9816. 相似文献