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991.
Wittnich C Belanger MP Bandali K 《Canadian journal of physiology and pharmacology》2006,84(8-9):859-865
Newborn hearts have restricted functional reserve and variable responsiveness to inotropes that could be partly due to differences in myocardial beta-adrenoceptors (beta-AR). To clarify this issue, this study documented ventricle-specific changes in myocardial beta-AR density and affinity during postnatal maturation. In vivo left and right ventricle (LV and RV, respectively) biopsies were obtained from newborn (3-day-old, n = 11), immature (14-day-old, n = 7), and adult (n = 6) pigs. Total beta-AR density (B(max), fmol/g) and dissociation constant (K(d), pmol/L) were determined by radioligand binding with I125 iodocyanopindolol. Overall, beta-AR B(max) in the LV significantly decreased with maturation. Interestingly, newborn animal hearts (LV and RV) subdivided into 2 groups: an adult-like low K(d) group with low B(max) and a fetal-like high K(d) group with high B(max), which were significantly different from one another. The high K(d) newborn group also had significantly higher K(d) and B(max) than both immature and adult hearts. Newborns had similar Bmax but higher Kd in the LV than the RV, whereas immature and adult hearts did not have ventricular differences. During maturation, beta-AR density decreased, whereas LV beta-AR binding affinity increased. Variable beta-AR maturity was also identified immediately post partum, which could potentially explain the newborn heart's variable responsiveness to inotropes. The subset of newborn hearts with lower binding affinity (reduced responsiveness) could also contribute to the newborn heart's overall reduction in functional reserve. 相似文献
992.
Iskander K Li J Han S Zheng B Jaiswal AK 《The Journal of biological chemistry》2006,281(41):30917-30924
NAD(P)H:quinone oxidoreductase 1 (NQO1) and NRH:quinone oxidoreductase 2 (NQO2) are cytosolic enzymes that catalyze metabolic reduction of quinones and derivatives. NQO1-null and NQO2-null mice were generated that showed decreased lymphocytes in peripheral blood, myeloid hyperplasia, and increased sensitivity to skin carcinogenesis. In this report, we investigated the in vivo role of NQO1 and NQO2 in immune response and autoimmunity. Both NQO1-null and NQO2-null mice showed decreased B-cells in blood, lower germinal center response, altered B cell homing, and impaired primary and secondary immune responses. NQO1-null and NQO2-null mice also showed susceptibility to autoimmune disease as revealed by decreased apoptosis in thymocytes and pre-disposition to collagen-induced arthritis. Further experiments showed accumulation of NADH and NRH, cofactors for NQO1 and NQO2, indicating altered intracellular redox status. The studies also demonstrated decreased expression and lack of activation of immune-related factor NF-kappaB. Microarray analysis showed altered chemokines and chemokine receptors. These results suggest that the loss of NQO1 and NQO2 leads to altered intracellular redox status, decreased expression and activation of NF-kappaB, and altered chemokines. The results led to the conclusion that NQO1 and NQO2 are endogenous factors in the regulation of immune response and autoimmunity. 相似文献
993.
TIGAR, a p53-inducible regulator of glycolysis and apoptosis 总被引:22,自引:0,他引:22
Bensaad K Tsuruta A Selak MA Vidal MN Nakano K Bartrons R Gottlieb E Vousden KH 《Cell》2006,126(1):107-120
The p53 tumor-suppressor protein prevents cancer development through various mechanisms, including the induction of cell-cycle arrest, apoptosis, and the maintenance of genome stability. We have identified a p53-inducible gene named TIGAR (TP53-induced glycolysis and apoptosis regulator). TIGAR expression lowered fructose-2,6-bisphosphate levels in cells, resulting in an inhibition of glycolysis and an overall decrease in intracellular reactive oxygen species (ROS) levels. These functions of TIGAR correlated with an ability to protect cells from ROS-associated apoptosis, and consequently, knockdown of endogenous TIGAR expression sensitized cells to p53-induced death. Expression of TIGAR may therefore modulate the apoptotic response to p53, allowing survival in the face of mild or transient stress signals that may be reversed or repaired. The decrease of intracellular ROS levels in response to TIGAR may also play a role in the ability of p53 to protect from the accumulation of genomic damage. 相似文献
994.
CRIg: a macrophage complement receptor required for phagocytosis of circulating pathogens 总被引:13,自引:0,他引:13
Helmy KY Katschke KJ Gorgani NN Kljavin NM Elliott JM Diehl L Scales SJ Ghilardi N van Lookeren Campagne M 《Cell》2006,124(5):915-927
The complement system serves an important role in clearance of pathogens, immune complexes, and apoptotic cells present in the circulation. Complement fragments deposited on the particle surface serve as targets for complement receptors present on phagocytic cells. Although Kupffer cells, the liver resident macrophages, play a dominant role in clearing particles in circulation, complement receptors involved in this process have yet to be identified. Here we report the identification and characterization of a Complement Receptor of the Immunoglobulin superfamily, CRIg, that binds complement fragments C3b and iC3b. CRIg expression on Kupffer cells is required for efficient binding and phagocytosis of complement C3-opsonized particles. In turn, Kupffer cells from CRIg-deficient mice are unable to efficiently clear C3-opsonized pathogens in the circulation, resulting in increased infection and mortality of the host. CRIg therefore represents a dominant component of the phagocytic system responsible for rapid clearance of C3-opsonized particles from the circulation. 相似文献
995.
Magne F Hachelaf W Suau A Boudraa G Mangin I Touhami M Bouziane-Nedjadi K Pochart P 《FEMS microbiology ecology》2006,58(3):563-571
For infants, the introduction of food other than breast milk is a high risk period due to diarrheal diseases, and may be corroborated with a shift in the faecal microbiota. This longitudinal study was the first undertaken to understand the effect of the supplementation on the infant's faecal microbiota and particularly the bifidobacteria. Eleven infants were enrolled. Their faecal microbiota were analysed using temporal temperature gradient gel electrophoresis (TTGE) with bacterial and bifidobacterial primers. In parallel, bifidobacterial counts were followed using competitive PCR. Three periods were distinguished: exclusive breastfeeding (Bf period), weaning (i.e. formula-milk addition, W period) and postweaning (i.e. breastfeeding cessation, Pw period). The bifidobacterial counts were not modified, reaching 10.5 (Log10 cells g(-1) wet weight). In the TTGE profiles, the main identified bands corresponded to Escherichia coli, Ruminococcus sp. and Bifidobacterium sp., more precisely Bifidobacterium longum, Bifidobacterium infantis and Bifidobacterium breve. For both TTGE profiles, the analysis of the distance suggested a maturation of the faecal microbiota but no correlation could be established with the diet. Despite a high interindividual variability, composition of the faecal microbiota appeared more homogenous after weaning and this point may be correlated with the cessation of breastfeeding. 相似文献
996.
Mura M Bull TJ Evans H Sidi-Boumedine K McMinn L Rhodes G Pickup R Hermon-Taylor J 《Applied and environmental microbiology》2006,72(1):854-859
Free-living protists are ubiquitous in the environment and form a potential reservoir for the persistence of animal and human pathogens. Mycobacterium avium subsp. paratuberculosis is the cause of Johne's disease, a systemic infection accompanied by chronic inflammation of the intestine that affects many animals, including primates. Most humans with Crohn's disease are infected with this chronic enteric pathogen. Subclinical infection with M. avium subsp. paratuberculosis is widespread in domestic livestock. Infected animals excrete large numbers of robust organisms into the environment, but little is known about their ability to replicate and persist in protists. In the present study we fed laboratory cultures of Acanthamoeba polyphaga with bovine and human strains of M. avium subsp. paratuberculosis. Real-time PCR showed that the numbers of the pathogens fell over the first 4 to 8 days and recovered by 12 to 16 days. Encystment of the amoebic cultures after 4 weeks resulted in a 2-log reduction in the level of M. avium subsp. paratuberculosis, which returned to the original level by 24 weeks. Extracts of resection samples of human gut from 39 patients undergoing abdominal surgery were fed to cultures of A. polyphaga. M. avium subsp. paratuberculosis detected by nested IS900 PCR with amplicon sequencing and visualized by IS900 in situ hybridization and auramine-rhodamine staining was found in cultures derived from 13 of the patients and was still present in the cultures after almost 4 years of incubation. Control cultures were negative. M. avium subsp. paratuberculosis has the potential for long-term persistence in environmental protists. 相似文献
997.
998.
We have extended our previous computational investigation of the cellulose lignin assembly by considering more complex systems. Surface coverage of cellulose, structural parameters such as molecular mass and structural features of the lignin models and the presence of an explicit hydrated environment have been taken into account to examine their influence on the associative interactions between cellulose and lignin. To this end, different lignin molecular models, from beta-O-4 dimers up to a 20-units oligomer, were considered. Independently of the system studied, the key feature of the adsorption is globally preserved: aromatic rings of lignin adopt a preferential parallel orientation relative to the cellulose surface. Such structural order appears to be limited to the first shell of lignin units adsorbed on the cellulose. The pre-organization of the lignin monolayer at the surface of cellulose is not significantly changed at the interface with water. However, adsorption significantly depends on the molecular mass and the structure of lignin. The structural order is significantly hindered by the presence of branching or some particular inter-units linkages in the structure of lignin. Such results rationalize the apparent contradiction between the available experimental results. 相似文献
999.
Afroze Syeda Humayra Yuki Hasegawa Izumi Nomura Young C. Chang Takeshi Sato Kazuhiro Takamizawa 《Biotechnology and Bioprocess Engineering》2005,10(1):40-46
Clostridium bifermentans strain DPH-1 has already been found to dechlorinate perchloroethylene (PCE) tocis-dichloroethylene (cis-DCE)via trichloroethylene (TCE). In this study, our investigation on different culture conditions of this DPH-1 strain was extended
to find a more efficient and cost effective growth medium composition for this DPH-1 strain in bioremediation practices. Temperature
dependency of strain DPH-1 showed that the growth starting time and PCE degradation at 15°C was very slow compared to that
of 30°C, but complete PCE degradation occurred in both cases. For the proper utilization of strain DPH-1 in more cost effective
bioremediation practices, a simpler composition of an effective media was studied. One component of the culture medium, yeast
extract, had been substituted by molasses, which served as a good source of electron donor. The DPH-1 strain in the medium
containing molasses, in the presence of K2HPO4 and KH2PO4, showed identical bacterial multiplication (0.135 mg protein mL−1h−1) and PCE degradation rates (0.38 μM/h) to those of the yeast extract containing medium. 相似文献
1000.
Karim Khalladi Abdulaziz Farooq Bart Sas Hamdi Chtourou Rachid Bouras Sebastien Racinais Sofiane Souissi Nadia Gaoua Karim Chamari Farid El Massioui 《Biology of sport / Institute of Sport》2021,38(3):305
This study aimed to determine if sleep quality and psychological factors were associated with time to meet the discharge criteria to return to sport (RTS) following anterior cruciate ligament reconstruction (ACL-R) among athletes. A cohort-study design included 89 athletes following ACL-R. Each participant completed a battery of questionnaires at 6 different time points: within 3 days of injury occurrence and at post-surgery (1.5 m, 3 m, 4.5 m, 6 m and when discharge criteria were met). Assessment included sleep quality and quantity, symptoms of depression, anxiety, stress, psychological readiness to RTS and fear of re-injury. The primary outcome was the time needed to meet all discharge criteria to RTS. Sleep parameters and psychological factors were not associated with time to meet the discharge criteria to RTS. However, athletes that had lower scores of anxiety (OR 1.2 (95% CI 1.0, 1.3) and insomnia (OR 1.2 (95% CI 1.0, 1.3) at baseline were more likely to meet the RTS discharge criteria. Athletes with better sleep quality at 3m, 4.5m and 6m were more likely to meet the RTS discharge criteria OR 1.3 (95% CI 1.1, 1.7), 2.0 (95% CI 1.1–3.4) and 1.4 (95% CI 1.0, 1.9) respectively. Sleep quality and psychological factors were not associated with time to meet the discharge criteria to RTS but impacted whether athletes adhered and completed their rehabilitation program or not. Monitoring sleep quality and psychological factors of athletes before and following ACL-R surgery is important to identify athletes who could have difficulties in adhering to and completing their rehabilitation program to RTS. 相似文献