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961.
An inhibition of the Na(+)/K(+)ATPase was previously shown to accompany and potentiate apoptosis in different experimental models. Since TNF-alpha is known to be a pro and anti-apoptotic cytokine, this work was undertaken to study the effect of TNF-alpha on the Na(+)/K(+)ATPase in HepG2 cells and to determine the signaling pathway involved. Cells were incubated for 1 h with TNF-alpha in presence and absence of PDTC, SP600125 and FK009, respective inhibitors of NF-KB, c-JNK, and caspases. The activity of the pump was assayed by measuring the ouabain-inhibitable release of inorganic phosphate, and changes in its expression were monitored by western blot analysis. TNF-alpha decreased significantly the activity and protein expression of the Na(+)/K(+)ATPase. NF-kappaB and caspases were found to be the main effectors of the cytokine, mediating respectively down-regulation and up-regulation of the pump. Their activity was however modulated at 1 h by c-JNK, which stimulated the caspases and inhibited NF-kappaB, resulting in a net inhibition of the ATPase, and probably favoring the apoptotic pathway. 相似文献
962.
Hassan HY Underhill PA Cavalli-Sforza LL Ibrahim ME 《American journal of physical anthropology》2008,137(3):316-323
We study the major levels of Y-chromosome haplogroup variation in 15 Sudanese populations by typing major Y-haplogroups in 445 unrelated males representing the three linguistic families in Sudan. Our analysis shows Sudanese populations fall into haplogroups A, B, E, F, I, J, K, and R in frequencies of 16.9, 7.9, 34.4, 3.1, 1.3, 22.5, 0.9, and 13% respectively. Haplogroups A, B, and E occur mainly in Nilo-Saharan speaking groups including Nilotics, Fur, Borgu, and Masalit; whereas haplogroups F, I, J, K, and R are more frequent among Afro-Asiatic speaking groups including Arabs, Beja, Copts, and Hausa, and Niger-Congo speakers from the Fulani ethnic group. Mantel tests reveal a strong correlation between genetic and linguistic structures (r = 0.31, P = 0.007), and a similar correlation between genetic and geographic distances (r = 0.29, P = 0.025) that appears after removing nomadic pastoralists of no known geographic locality from the analysis. The bulk of genetic diversity appears to be a consequence of recent migrations and demographic events mainly from Asia and Europe, evident in a higher migration rate for speakers of Afro-Asiatic as compared with the Nilo-Saharan family of languages, and a generally higher effective population size for the former. The data provide insights not only into the history of the Nile Valley, but also in part to the history of Africa and the area of the Sahel. 相似文献
963.
964.
Ibrahim EM Arenskötter M Luftmann H Steinbüchel A 《Applied and environmental microbiology》2006,72(5):3375-3382
The enrichment and isolation of thermophilic bacteria capable of rubber [poly(cis-1,4-isoprene)] degradation revealed eight different strains exhibiting both currently known strategies used by rubber-degrading mesophilic bacteria. Taxonomic characterization of these isolates by 16S rRNA gene sequence analysis demonstrated closest relationships to Actinomadura nitritigenes, Nocardia farcinica, and Thermomonospora curvata. While strains related to N. farcinica exhibited adhesive growth as described for mycolic acid-containing actinomycetes belonging to the genus Gordonia, strains related to A. nitritigenes and T. curvata formed translucent halos on natural rubber latex agar as described for several mycelium-forming actinomycetes. For all strains, optimum growth rates were observed at 50 degrees C. The capability of rubber degradation was confirmed by mineralization experiments and by gel permeation chromatography (GPC). Intermediates resulting from early degradation steps were purified by preparative GPC, and their analysis by infrared spectroscopy revealed the occurrence of carbonyl carbon atoms. Staining with Schiff's reagent also revealed the presence of aldehyde groups in the intermediates. Bifunctional isoprenoid species terminated with a keto and aldehyde function were found by matrix-assisted laser desorption ionization-time-of-flight and electrospray ionization mass spectrometry analyses. Evidence was obtained that biodegradation of poly(cis-1,4-isoprene) is initiated by endocleavage, rather than by exocleavage. A gene (lcp) coding for a protein with high homology to Lcp (latex-clearing protein) from Streptomyces sp. strain K30 was identified in Nocardia farcinica E1. Streptomyces lividans TK23 expressing this Lcp homologue was able to cleave synthetic poly(cis-1,4-isoprene), confirming its involvement in initial polymer cleavage. 相似文献
965.
In this paper, we propose a genetic algorithm based approach to determine the pose of an object in Automated Visual Inspection having three degrees of freedom. We have investigated the effect of noise at 20 dB SNR and also mismatch resulting from incorrect correspondences between the object space points and the image space points, on the estimation of pose parameters. The maximum error in translation parameters is less than 0.45 cm and rotational error is less than 0.2 degree at 20 dB SNR. The error in parameter estimation is insignificant upto 7 pairs of mismatched points out of 24 points in object space and the results skyrockets when 8 or more pairs of points are mismatched. We have compared our result with that obtained by least square technique and it shows that GA based method outperform the gradient based technique when the number of vertices of the object to be inspected is small. These results have clearly established the robustness of GA in estimating the pose of an object with small number of vertices in automated visual inspection. 相似文献
966.
Rajamohan D Banerjee RK Back LH Ibrahim AA Jog MA 《Journal of biomechanical engineering》2006,128(3):347-359
A major consequence of stent implantation is restenosis that occurs due to neointimal formation. This patho-physiologic process of tissue growth may not be completely eliminated. Recent evidence suggests that there are several factors such as geometry and size of vessel, and stent design that alter hemodynamic parameters, including local wall shear stress distributions, all of which influence the restenosis process. The present three-dimensional analysis of developing pulsatile flow in a deployed coronary stent quantifies hemodynamic parameters and illustrates the changes in local wall shear stress distributions and their impact on restenosis. The present model evaluates the effect of entrance flow, where the stent is placed at the entrance region of a branched coronary artery. Stent geometry showed a complex three-dimensional variation of wall shear stress distributions within the stented region. Higher order of magnitude of wall shear stress of 530 dyn/cm2 is observed on the surface of cross-link intersections at the entrance of the stent. A low positive wall shear stress of 10 dyn/cm2 and a negative wall shear stress of -10 dyn/cm2 are seen at the immediate upstream and downstream regions of strut intersections, respectively. Modified oscillatory shear index is calculated which showed persistent recirculation at the downstream region of each strut intersection. The portions of the vessel where there is low and negative wall shear stress may represent locations of thrombus formation and platelet accumulation. The present results indicate that the immediate downstream regions of strut intersections are areas highly susceptible to restenosis, whereas a high shear stress at the strut intersection may cause platelet activation and free emboli formation. 相似文献
967.
Recent studies on the metabolic activities of genus Rhodococcus have shown rhodococci to be of important use in industrial, pharmaceutical and environmental biotechnology. The increasing economic significance of Rhodococcus encourages renewed efforts to characterize their genetic systems, as Rhodococcus genetics are still poorly understood. The goal of this study is to adapt a transposon system for use in creating random mutagenesis in Rhodococcus erythropolis. A plasmid carrying IS1415, a member of IS21 family identified from Rerythropolis, has been constructed and designated as pTNR. pTNR is a non-replicating transposon tool introduced into target cells by electroporation. During its transposition, the transposable-marker gene is separated from the open reading frames (istAB) of IS1415, which should avoid secondary transposition. Transposition of pTNR into wild-type R. erythropolis created mutagenesis with a high efficiency of 1.23x10(6)mutants per microgram plasmid DNA. However, it could also be transposed into other Rhodococcus spp. at lower frequencies in comparison with that of R. erythropolis. It has been indicated by Southern hybridization that the generated kanamycin-resistant mutants were resulted from single transposition event of pTNR. The results also revealed that the transposable-marker gene of pTNR was randomly inserted into the chromosomal DNA of R. erythropolis. The affected DNA regions carrying the transposed DNA element could be conveniently recovered for further characterization using a plasmid rescue procedure. Sequence data of the insertion sites of 40 random mutants analyzed indicated that transposition of pTNR generated 6-bp direct target duplications in 36 cases, while in the remaining four mutants; it generated 5- or 7-bp target duplications (two cases each). This study concluded that pTNR could be served as an efficient genetic tool for construction of random mutagenesis system in Rhodococcus species. 相似文献
968.
Postpartum scalp hair samples from 82 term-pregnancy mother/neonate pairs were analyzed for their concentration of zinc (Zn),
copper (Cu), cadmium (Cd), and lead (Pb), using inductively coupled plasma-mass spectrometry. Maternal and neonatal Zn concentrations
had geometric means (and 99% confidence intervals) of 122.5 μg/g (117.9–131.5 μg/g) and 146.9 μg (141.5–156.7 μg/g) respectively.
Corresponding Cu values were 18.4 μg/g (17.6–23.8 μg/g) and 6.7 μg/g (6.3–7.6 μg/g). Those of Cd were 0.49 μg/g (0.47–0.69
μg/g) in the mothers and 0.57 μg/g (0.55–0.86 μg/g) in the neonates. For Pb, they were 7.95 μg/g (7.60–9.32 μg/g) and 4.56
μg/g (4.39–5.56 μg/g). Cigaret smoking, despite its relatively low prevalence (19.5%), was associated with lower Zn and higher
Cd and Pb concentrations and in lower Zn/Cd and Zn/Pb molar concentration ratios. Smoking also altered interelemental relationships,
particularly those of Zn with Cd and Pb and those between Cd and Pb. Smoking frequency appeared to show negative dose-response
effects on maternal and neonatal Zn concentrations, Zn/Pb molar concentration ratios, and birth weight. Mothers with a history
of oral contraceptive (OC) usage had significantly higher Cu concentrations and lower Zn/Cu molar concentration ratios than
nonusers, with the highest Cu concentrations and lowest Zn/Cu values being associated with third-generation OCs. No similar
effects were elicited in the respective neonatal Cu concentrations. Neither alcohol consumption nor prenatal supplementation
with iron and/or folic acid had discernible effects on the maternal or neonatal elemental concentrations. The data from this
study suggest that in a given population of term-pregnancy mothers and neonates, significant interindividual variations in
hair trace element concentrations can occur, irrespective of commonality of general environment, and that lifestyle factors,
including cigaret smoking and OC usage history, can be significant contributory factors to such variations. The data are discussed
in relation to the effects of smoking-associated exposure to Cd and Pb exposure on Zn availability for placental transfer,
as well as on the quantitative maternal Zn supply levels to the fetus resulting from the known tendency of smokers to have
lower dietary intakes of Zn. The higher Cu concentrations in OC users are discussed in relation to altered Cu metabolism,
characterized by increased synthesis of the Cu-binding protein, ceruloplasmin, as an acute-phase antioxidant response to altered
lipid profile and increased lipid oxidation. 相似文献
969.
Shehab DK Al-Jarallah KF Al-Awadhi AM Al-Herz A Nahar I Haider MZ 《Journal of biomedical science》2008,15(1):61-67
Summary Low back pain (LBP) is a common medical problem. Interaction between genetic and environmental factors predisposes individuals
to LBP even at an early age. Inflammatory back pain or spondylarthropathies include ankylosing spondylitis (AS), psoriatic
arthritis (PSA), reactive arthritis enteropathic and undifferentiated arthropathies. Angiotensin-converting enzyme (ACE) plays
an important role in circulatory homeostasis, physiology of vasculature and inflammation. The insertion–deletion (I/D) polymorphism
of the ACE gene has been shown to determine the plasma and tissue levels of ACE especially in the synovial fluid. The aim
of this study was to investigate an association between ACE gene I/D polymorphism and inflammatory back pain (spondylarthropathies)
secondary to ankylosing spondylitis (AS), psoriatic arthritis, inflammatory bowel disease and undifferentiated spondylarthropathies.
The prevalence of ACE gene I/D polymorphism genotypes was determined in 63 patients with inflammatory back pain by polymerase
chain reaction (PCR) and compared with that in 111 healthy controls. Of the 63 patients studied, 45 (71.4%) were with AS,
13 (20.6%) were with PSA, 4 (6.3%) were with reactive arthropathy and 1 (1.6%) manifested undifferentiated arthropathy. There
were 43 males and 20 females. Mean age of patients was 39.0 ± 11.36 years, age at onset of spondylarthropathy was 27.7 ± 7.49 years
and disease duration was 10.3 ± 7.74 months. The controls were selected to match with the patients group in terms of gender
ratio, age and ethnicity. The ACE gene polymorphism showed an overall significant difference between patients and controls
(p = 0.050). When the ID and II genotype frequency was combined and compared with that for DD genotype amongst patient and control
groups, a considerably higher incidence was detected for ID and II genotypes than the DD genotype in spondylarthropathy patients
compared to that in the controls (p = 0.036). This study showed a significant association of the I-allele of ACE gene I/D polymorphism with spondylarthropathy
in Kuwaiti Arabs. 相似文献
970.
Rummenie VT Matsumoto Y Dogru M Wang Y Hu Y Ward SK Igarashi A Wakamatsu T Ibrahim O Goto E Luyten G Inoue H Saito I Shimazaki J Tsubota K 《Cytokine》2008,43(2):200-208
Purpose: To prospectively investigate the effects of acute passive cigarette smoke exposure on the ocular surface and tear film in healthy non-smokers. Methods: Twelve right eyes of 12 subjects without any ocular diseases were examined before, 5 min, and 24 h after 5 min of passive cigarette smoke exposure in a controlled smoke chamber. Tear samples were obtained before, 5 min and 24 h after smoke exposure to detect tear hexanoyl-lysine (HEL), acrolein and inflammatory cytokine concentrations. Tear evaporation rate, DR-1 tear film lipid layer interferometry, tear film break-up time (TBUT), ocular surface fluorescein staining (FS) and Rose Bengal staining (RB), Schirmer I test were performed before, 5 min, and 24 h after smoke exposure. Conjunctival impression cytology (IC) and brush cytology (BC) were carried out before and 24 h after smoke exposure. Results: Tear evaporation rate, tear lipid spread time, tear film break-up time, and vital staining scores showed significant worsening with passive smoke exposure. Tear HEL and IL-6 concentrations increased significantly 24 h after smoke exposure. Tear acrolein level showed an insignificant increase at 5 min. IC and RT-PCR revealed a significant reduction in goblet cell density, a shift toward higher squamous metaplasia grades and a significant downregulation of MUC5AC mRNA expression at 24 h. Conclusion: Even brief passive exposure to cigarette smoke in healthy non-smoker subjects was associated with adverse effects on the ocular surface health as evidenced by an increase of tear inflammatory cytokines, tear lipid peroxidation products and decrease of mucosal defense resulting in tear instability and damage to the ocular surface epithelia. 相似文献