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211.
Mehmet Okan Özkaya Mustafa Nazıroğlu Cihan Barak Murat Berkkanoglu 《Biological trace element research》2011,139(1):1-9
We investigated effects of multivitamin/mineral supplementation on element levels in serum and follicular fluid of women undergoing
IVF. We used three groups in this study. The first group was used as an age-matched and nonpregnant control (n = 13). Group 2 (n = 30) constituted the IVF group and women in the third group who were undergoing IVF also received a multivitamin/mineral
tablet daily for 45 days. Follicular fluid and serum selenium and zinc levels and follicular fluid copper levels were lower
in IVF patients than in controls although follicular fluid aluminum and iron levels were higher in IVF patients than in controls.
However, follicular fluid and serum aluminum, copper, zinc and selenium levels, and serum magnesium levels were higher in
the multivitamin/mineral group than in the IVF group although follicular fluid iron levels were lower in the multivitamin/mineral
group than in the IVF group. In conclusion, we observed that copper, zinc, and selenium in serum and follicular fluid decreased
in women undergoing IVF. Multivitamin/mineral supplementation in serum and follicular fluid of women undergoing IVF normalized
the trace element levels. 相似文献
212.
213.
The potentially confounded effects of factors affecting breeding dispersal have rarely been simultaneously examined. The consequences
of breeding dispersal are even less studied, presenting a paradox: breeding dispersal seldom seems to improve breeding success,
despite its presumed adaptiveness. We studied the causes and consequences of breeding dispersal in female-philopatric eiders
(Somateria mollissima) in relation to the spatiotemporal predictability of nest success. Previous nest fate, breeding experience, and breeding
density simultaneously affected breeding dispersal. Dispersal distances were longer among inexperienced breeders and after
failed breeding. Individual dispersal distances decreased with increasing nest-site-specific breeding density, whereas island-specific
nesting success peaked at intermediate densities. The fate of neighbouring nests (‘public information’) did not influence
dispersal. Breeding dispersal was unrelated to subsequent hatching success, controlling for individual quality (body condition,
breeding experience, previous nest fate), while it delayed hatch date, which is likely to impair reproductive success. This
delay may result from the loss of acquired information of local breeding conditions, prolonging nest prospecting and establishment,
also helping explain why breeding dispersal did not increase at high breeding densities, despite a potential reduction in
nesting success. In long-lived species, however, dispersal-induced reductions in reproductive output in one season could be
offset by improved parental survival prospects. Careful nest prospecting may be profitable, because overall nest success had
a strong island-specific component but showed weak temporal variation, and successive individual nest fates were predictable
between years. Once a safe nest site is found, females may breed at the same place successfully for many years. 相似文献
214.
Tissue engineering and regenerative medicine aim to produce tissue substitutes to restore lost functions of tissues and organs. This includes cell therapies, induction of tissue/organ regeneration by biologically active molecules, or transplantation of in vitro grown tissues. This review article discusses advanced cell therapies that make use of scaffolds and scaffold-free approaches. The first part of this article covers the basic characteristics of scaffolds, including characteristics of scaffold material, fabrication and surface functionalization, and their applications in the construction of hard (bone and cartilage) and soft (nerve, skin, blood vessel, heart muscle) tissue substitutes. In addition, cell sources as well as bioreactive agents, such as growth factors, that guide cell functions are presented. The second part in turn, examines scaffold-free applications, with a focus on the recently discovered cell sheet engineering. This article serves as a good reference for all applications of advanced cell therapies and as well as advantages and limitations of scaffold-based and scaffold-free strategies. 相似文献
215.
Paul G Özen I Christophersen NS Reinbothe T Bengzon J Visse E Jansson K Dannaeus K Henriques-Oliveira C Roybon L Anisimov SV Renström E Svensson M Haegerstrand A Brundin P 《PloS one》2012,7(4):e35577
Blood vessels and adjacent cells form perivascular stem cell niches in adult tissues. In this perivascular niche, a stem cell with mesenchymal characteristics was recently identified in some adult somatic tissues. These cells are pericytes that line the microvasculature, express mesenchymal markers and differentiate into mesodermal lineages but might even have the capacity to generate tissue-specific cell types. Here, we isolated, purified and characterized a previously unrecognized progenitor population from two different regions in the adult human brain, the ventricular wall and the neocortex. We show that these cells co-express markers for mesenchymal stem cells and pericytes in vivo and in vitro, but do not express glial, neuronal progenitor, hematopoietic, endothelial or microglial markers in their native state. Furthermore, we demonstrate at a clonal level that these progenitors have true multilineage potential towards both, the mesodermal and neuroectodermal phenotype. They can be epigenetically induced in vitro into adipocytes, chondroblasts and osteoblasts but also into glial cells and immature neurons. This progenitor population exhibits long-term proliferation, karyotype stability and retention of phenotype and multipotency following extensive propagation. Thus, we provide evidence that the vascular niche in the adult human brain harbors a novel progenitor with multilineage capacity that appears to represent mesenchymal stem cells and is different from any previously described human neural stem cell. Future studies will elucidate whether these cells may play a role for disease or may represent a reservoir that can be exploited in efforts to repair the diseased human brain. 相似文献
216.
Ö Akkaya SI Oztürk A Bolhuis F Gümüşel 《World journal of microbiology & biotechnology》2012,28(5):2159-2164
Penicillin G acylase (PA) is an important enzyme used in the industrial production of b-lactam antibiotics. In this study,
the effects of mutations in the translation initiation region of the Escherichia coli pac gene, encoding periplasmic PA, were examined. Several mutations led to increased amounts of PA activity, including those
that lengthened the spacer region between the ribosome binding site and the ATG start codon, and those with altered codons
on positions +2 and +4 relative to the start codon. These results indicated that the wild-type sequence of the pac gene does not provide maximum expression levels and that the strategies applied in this study can be used to improve production
of PA in E. coli. Unexpectedly, our study also suggested that translocation of PA was, in contrast to earlier reports, shown not to require
the Twin-arginine translocation pathway for transport into the periplasm. 相似文献
217.
Ozturkcan SA Turhan K Turgut Z Karadayi M Gulluce M 《Journal of biochemical and molecular toxicology》2012,26(7):258-263
The aim of this study was to determine the antigenotoxic potential of two newly synthesized β-aminoketones against N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 9-aminoacridine (9-AA)-induced mutagenesis. The mutant bacterial tester strains were MNNG-sensitive Escherichia coli WP2 uvrA and 9-AA-sensitive Salmonella typhimurium TA1537. Both test compounds showed significant antimutagenic activity at various tested concentrations. The inhibition rates ranged from 29.5% (compound 1: 2 mM/plate) to 47.5% (compound 2: 1.5 mM/plate) for MNNG and from 25.0% (compound 2: 1 mM/plate) to 52.1% (compound 2: 2.5 mM/plate) for 9-AA genotoxicity. Moreover, the mutagenicity of the test compounds was investigated by using the same strains. Neither test compound has mutagenic properties on the bacterial strains at the tested concentrations. Thus, the findings of the present study give valuable information about chemical prevention from MNNG and 9-AA genotoxicity by using synthetic β-aminoketones. 相似文献
218.
Caffeic Acid Phenethyl Ester Modulates Gentamicin-Induced Oxidative Nephrotoxicity in Kidney of Rats
In this study, the modulator effect of caffeic acid phenethyl ester (CAPE) on the oxidative nephrotoxicity of gentamicin in
the kidneys of rats was investigated by determining indices of lipid peroxidation and the activities of antioxidant enzymes
as well as by histological analyses. Forty female Wistar albino rats were randomly divided into four groups, namely control,
gentamicin, CAPE, and gentamicin plus CAPE. On the 12th day of the study, all rats were sacrificed and then blood samples
and kidneys were taken. Lipid peroxidation and nitric oxide levels, glutathione peroxidase (GSH-Px), superoxide dismutase
(SOD) and catalase (CAT) enzyme activities, and histological evaluation were measured in kidneys of rats. Levels of blood
urea nitrogen and creatinine were studied in serum. CAPE with gentamicin caused decreases in lipid peroxidation, nitric oxide,
urea nitrogen, and creatinine levels, although it caused increases in CAT, GSH-Px, and SOD activities when compared with gentamicin
alone. In addition, on histological evaluation, the renal damage caused by gentamicin alone appeared much higher than that
caused by CAPE plus gentamicin. It is concluded that oxidative stress plays a critical role in causing gentamicin nephrotoxicity
and that this nephrotoxicity may be significantly reduced by CAPE. 相似文献
219.
Keith P. Romano Akbar Ali Cihan Aydin Djade Soumana Ay?egül ?zen Laura M. Deveau Casey Silver Hong Cao Alicia Newton Christos J. Petropoulos Wei Huang Celia A. Schiffer 《PLoS pathogens》2012,8(7)
Hepatitis C virus (HCV) infects over 170 million people worldwide and is the leading cause of chronic liver diseases, including cirrhosis, liver failure, and liver cancer. Available antiviral therapies cause severe side effects and are effective only for a subset of patients, though treatment outcomes have recently been improved by the combination therapy now including boceprevir and telaprevir, which inhibit the viral NS3/4A protease. Despite extensive efforts to develop more potent next-generation protease inhibitors, however, the long-term efficacy of this drug class is challenged by the rapid emergence of resistance. Single-site mutations at protease residues R155, A156 and D168 confer resistance to nearly all inhibitors in clinical development. Thus, developing the next-generation of drugs that retain activity against a broader spectrum of resistant viral variants requires a comprehensive understanding of the molecular basis of drug resistance. In this study, 16 high-resolution crystal structures of four representative protease inhibitors – telaprevir, danoprevir, vaniprevir and MK-5172 – in complex with the wild-type protease and three major drug-resistant variants R155K, A156T and D168A, reveal unique molecular underpinnings of resistance to each drug. The drugs exhibit differential susceptibilities to these protease variants in both enzymatic and antiviral assays. Telaprevir, danoprevir and vaniprevir interact directly with sites that confer resistance upon mutation, while MK-5172 interacts in a unique conformation with the catalytic triad. This novel mode of MK-5172 binding explains its retained potency against two multi-drug-resistant variants, R155K and D168A. These findings define the molecular basis of HCV N3/4A protease inhibitor resistance and provide potential strategies for designing robust therapies against this rapidly evolving virus. 相似文献
220.