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81.
This study focuses on the cytotoxic effects of fumonisin B1 (FB1) on both immortalised and immortalised and subsequently transfected normal human bronchial epithelial (NHBE) cells of human
origin using four bioassays. While the MTT, Neutral Red and hexosaminidase colorimetric assays showed little difference between
the toxic effects on the two related cell lines, the clonogenic assay, measuring cell survival and proliferation, indicated
that FB1 had a more toxic effect on the nontransfected cells. This kind ofin vitro approach using cells which retain many characteristics of normal cell growth and differentiation can go some way to developing
evaluation models for food safety in the case of mycotoxin contamination without resorting totally to whole animal testing.
Nevertheless, one or two cytotoxicity tests may be inadequate for a complete appraisal of toxic potential: rather, as wide
a range of methodologies as feasible should be employed initially before meaningful conclusions may be drawn. 相似文献
82.
针对气候变化和城市化对富饶的三角洲地区带来的洪涝风险、生态、社会—文化价值流失等威胁,提出将三角洲城市化进程视为一系列具有独立动态特征和速率变化的复杂社会—生态系统(子系统),急需为保障该类型区域的可持续发展提供空间战略,以协助修复系统漏洞并增强应对自然和人工威胁的能力,以珠江三角洲为例,针对城市化进程中三角洲区域的适应性城市转型,提出基于景观的区域设计方法。通过对自然和城市景观要素转型性循环的各类动态变化进行评估,得到生态动力型区域设计战略,为城市化进程中的自然和社会—文化发展提供更多机遇。提出保障水安全和全纳性社会—生态设计的适应性转型视角。 相似文献
83.
M Kale R Ramsey-Goldman S Bernatsky MB Urowitz D Gladman PR Fortin M Petri E Yelin S Manzi S Edworthy O Nived S-C Bae D Isenberg A Rahman JG Hanly C Gordon S Jacobsen E Ginzler DJ Wallace GS Alarcón MA Dooley L Gottesman K Steinsson A Zoma J-L Senécal S Barr G Sturfelt L Dreyer L Criswell J Sibley JL Lee AE Clarke 《Arthritis research & therapy》2012,14(Z3):A15
84.
Intrathecal (i.t.) injection of somatostatin has been reported to depress nociceptive reflexes as well as to cause severe disturbance of somatomotor performance. The present study was designed to assess the dependence of these effects on the dose and the interval between implantation of the catheter and i.t. injection of somatostatin in rats. The effects produced by i.t. injection of somatostatin consisted of an increase in the response latencies of nociceptive responses to noxious heat, impairment of motor performance and grooming behavior, convulsions, and death. Except for grooming behavior, these were related in incidence and degree to the dose and the interval, the potency of somatostatin being highest at short intervals. Sham operations also affected the effectiveness of somatostatin. 相似文献
85.
At the early onset of the 20th century, several studies already reported that the gray matter was implicated in the histopathology of multiple sclerosis
(MS). However, as white matter pathology long received predominant attention in this disease, and histological staining techniques
for detecting myelin in the gray matter were suboptimal, it was not until the beginning of the 21st century that the true extent and importance of gray matter pathology in MS was finally recognized. Gray matter damage was
shown to be frequent and extensive, and more pronounced in the progressive disease phases. Several studies subsequently demonstrated
that the histopathology of gray matter lesions differs from that of white matter lesions. Unfortunately, imaging of pathology
in gray matter structures proved to be difficult, especially when using conventional magnetic resonance imaging (MRI) techniques.
However, with the recent introduction of several more advanced MRI techniques, the detection of cortical and subcortical damage
in MS has considerably improved. This has important consequences for studying the clinical correlates of gray matter damage.
In this review, we provide an overview of what has been learned about imaging of gray matter damage in MS, and offer a brief
perspective with regards to future developments in this field. 相似文献
86.
Rodrigo D. Cunha Celina M. Abreu Luis M. F. Gonzalez Monique Nijhuis Dorien de Jong Renato S. Aguiar Adriana O. Afonso Rodrigo M. Brindeiro Amilcar Tanuri 《PloS one》2012,7(10)
Background
HIV-1 subtype B is the most prevalent in developed countries and, consequently, it has been extensively studied. On the other hand, subtype C is the most prevalent worldwide and therefore is a reasonable target for future studies. Here we evaluate the acquisition of resistance and the viability of HIV-1 subtype B and C RT clones from different isolates that were subjected to in vitro selection pressure with zidovudine (ZDV) and lamivudine (3TC).Methods/Principal Findings
MT4 cells were infected with chimeric virus pseudotyped with RT from subtype B and C clones, which were previously subjected to serial passage with increasing concentrations of ZDV and 3TC. The samples collected after each passage were analyzed for the presence of resistance mutations and VL. No differences were found between subtypes B and C in viral load and resistance mutations when these viruses were selected with 3TC. However, the route of mutations and the time to rebound of subtype B and C virus were different when subjected to ZDV treatment. In order to confirm the role of the mutations detected, other clones were generated and subjected to in vitro selection. RT subtype B virus isolates tended to acquire different ZDV resistance mutations (Q151M and D67N or T215Y, D67D/N and F214L) compared to subtype C (D67N, K70R, T215I or T215F).Conclusions/Significance
This study suggests that different subtypes have a tendency to react differently to antiretroviral drug selection in vitro. Consequently, the acquisition of resistance in patients undergoing antiretroviral therapy can be dependent on the subtypes composing the viral population. 相似文献87.
Nijhuis J van Dielen FM Fouraschen SM van den Broek MA Rensen SS Buurman WA Greve JW 《Obesity (Silver Spring, Md.)》2007,15(6):1395-1399
Objective: Increased plasma levels of endothelial activation markers in obese subjects reflect the positive association between cardiovascular diseases and obesity. The pro‐inflammatory state associated with obesity is thought to play a major role in endothelial cell activation in severely obese individuals. Previous studies demonstrated that long‐term weight loss after bariatric surgery is accompanied by a decreased proinflammatory state. However, little is known about the long‐term effects of bariatric surgery on endothelial cell activation. Research Methods and Procedures: Plasma levels of soluble intercellular adhesion molecule‐1 (sICAM‐1), soluble endothelial selectin (sE‐selectin), and soluble vascular cell adhesion molecule‐1 (sVCAM‐1), all markers of endothelial cell activation, and of their regulators adiponectin and resistin were measured at different time‐points postoperatively in 26 consecutive patients who underwent restrictive surgery, with a follow‐up of 2 years. Results: During the first 6 months after bariatric surgery, sE‐selectin levels decreased. Despite substantial weight loss, sICAM‐1 and sVCAM‐1 plasma levels did not decrease significantly. After 24 months, sICAM‐1 levels were significantly decreased, whereas sE‐selectin levels were further decreased. However, sVCAM‐1 levels remained elevated. Adiponectin levels did not change significantly during the first 6 months after bariatric surgery, whereas resistin levels increased. After 24 months, adiponectin levels were similar to normal‐weight controls, but resistin levels remained high. Discussion: Reductions in plasma levels of different markers of endothelial activation after bariatric surgery show different temporal patterns, suggesting that distinct mechanisms are involved in their regulation. Although not all endothelial activation markers normalize after bariatric surgery, our findings suggest that bariatric surgery can reduce endothelial activation in the long term. 相似文献
88.
John de Kruif Arjen Kramer Therèse Visser Carina Clements Roy Nijhuis Freek Cox Vanessa van der Zande Renate Smit Daniel Pinto Mark Throsby Ton Logtenberg 《Journal of molecular biology》2009,387(3):548-4235
To study the contribution of antibody light (L) chains to the diversity and binding properties of immune repertoires, a phage display repertoire was constructed from a single human antibody L chain and a large collection of antibody heavy (H) chains harvested from the blood of two human donors immunized with tetanus toxoid (TT) vaccine. After selection for binding to TT, 129 unique antibodies representing 53 variable immunoglobulin H chain (VH) gene rearrangements were isolated. This panel of anti-TT antibodies restricted to a single variable immunoglobulin L chain (VL) could be organized into 17 groups binding non-competing epitopes on the TT molecule. Comparison of the VH regions in this VL-restricted panel with a previously published repertoire of anti-TT VH regions with cognate VH-VL pairing showed a very similar distribution of VH, DH and JH gene segment utilization and length of the complementarity-determining region 3 of the H chain. Surface plasmon resonance analysis of the single-VL anti-TT repertoire unveiled a range of affinities, with a median monovalent affinity of 2 nM. When the single-VL anti-TT VH repertoire was combined with a collection of naïve VL regions and again selected for binding to TT, many of the VH genes were recovered in combination with a diversity of VL regions. The affinities of a panel of antibodies consisting of a single promiscuous anti-TT VH combined with 15 diverse VL chains were determined and found to be identical to each other and to the original isolate restricted to a single-VL chain. Based on previous estimates of the clonal size of the human anti-TT repertoire, we conclude that up to 25% of human anti-TT-encoding VH regions from an immunized repertoire have promiscuous features. These VH regions readily combine with a single antibody L chain to result in a large panel of anti-TT antibodies that conserve the expected epitope diversity, VH region diversity and affinity of a natural repertoire. 相似文献
89.
Four Gram-negative bacterial strains, recovered from clay soils cultivated with different crops in the Netherland, were subjected to a polyphasic taxonomic study in order to clarify their taxonomic status. Comparative analysis of the 16S rRNA gene sequences revealed that they belong to the genus Lysobacter and to be highly related to the type strains of L. antibioticus DSM 2044T, L. gummosus DSM 6980T, and L. capsici DSM 19286T, displaying 99.1–99.3%, 99.2–99.6% and 99.4–100% sequence similarities, respectively, to these species. The results of DNA–DNA hybridization studies unambigiously indicated that the four strains belonged to the species L. capsici. Nevertheless, DNA fingerprinting and phenotypic characterization indicated that there was a considerable diversification and niche differentiation among the strains belonging to L. capsici. The newly identified L. capsici strains strongly inhibit Rhizoctonia solani AG2 and originate from Rhizoctonia-suppressive soils where also populations of L. antibioticus and L. gummosus were present. This is the first report of the presence of combined populations of closely related Lysobacter spp. within agricultural soils. 相似文献
90.