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排序方式: 共有349条查询结果,搜索用时 15 毫秒
41.
Lund RJ Nikula T Rahkonen N Närvä E Baker D Harrison N Andrews P Otonkoski T Lahesmaa R 《Stem cell research》2012,9(3):192-195
Genomic integrity of human pluripotent stem cell (hPSC) lines requires routine monitoring. We report here that novel karyotyping assay, utilizing bead-bound bacterial artificial chromosome probes, provides a fast and easy tool for detection of chromosomal abnormalities in hPSC lines. The analysis can be performed from low amounts of DNA isolated from whole cell pools with simple data analysis interface. The method enables routine screening of stem cell lines in a cost-efficient high-throughput manner. 相似文献
42.
Expression analysis of immune response genes in fish epithelial cells following ranavirus infection 总被引:1,自引:0,他引:1
Ranaviruses (family Iridoviridae) are a growing threat to fish and amphibian populations worldwide. The immune response to ranavirus infection has been studied in amphibians, but little is known about the responses elicited in piscine hosts. In this study, the immune response and apoptosis induced by ranaviruses were investigated in fish epithelial cells. Epithelioma papulosum cyprini (EPC) cells were infected with four different viral isolates: epizootic haematopoietic necrosis virus (EHNV), frog virus 3 (FV3), European catfish virus (ECV) and doctor fish virus (DFV). Quantitative real-time PCR (qPCR) assays were developed to measure the mRNA expression of immune response genes during ranavirus infection. The target genes included tumour necrosis factor α (TNF-α), interleukin-1β (IL-1β), β2-microglobulin (β2M), interleukin-10 (IL-10) and transforming growth factor β (TGF-β). All ranaviruses elicited changes in immune gene expression. EHNV and FV3 caused a strong pro-inflammatory response with an increase in the expression of both IL-1β and TNF-α, whereas ECV and DFV evoked transient up-regulation of regulatory cytokine TGF-β. Additionally, all viral isolates induced increased β2M expression as well as apoptosis in the EPC cells. Our results indicate that epithelial cells can serve as an in vitro model for studying the mechanisms of immune response in the piscine host in the first stages of ranavirus infection. 相似文献
43.
Minna K. Karjalainen Johanna M. Huusko Johanna Ulvila Jenni Sotkasiira Aino Luukkonen Kari Teramo Jevon Plunkett Verneri Anttila Aarno Palotie Ritva Haataja Louis J. Muglia Mikko Hallman 《PloS one》2012,7(12)
Preterm birth is the major cause of neonatal mortality and morbidity. In many cases, it has severe life-long consequences for the health and neurological development of the newborn child. More than 50% of all preterm births are spontaneous, and currently there is no effective prevention. Several studies suggest that genetic factors play a role in spontaneous preterm birth (SPTB). However, its genetic background is insufficiently characterized. The aim of the present study was to perform a linkage analysis of X chromosomal markers in SPTB in large northern Finnish families with recurrent SPTBs. We found a significant linkage signal (HLOD = 3.72) on chromosome locus Xq13.1 when the studied phenotype was being born preterm. There were no significant linkage signals when the studied phenotype was giving preterm deliveries. Two functional candidate genes, those encoding the androgen receptor (AR) and the interleukin-2 receptor gamma subunit (IL2RG), located near this locus were analyzed as candidates for SPTB in subsequent case-control association analyses. Nine single-nucleotide polymorphisms (SNPs) within these genes and an AR exon-1 CAG repeat, which was previously demonstrated to be functionally significant, were analyzed in mothers with preterm delivery (n = 272) and their offspring (n = 269), and in mothers with exclusively term deliveries (n = 201) and their offspring (n = 199), all originating from northern Finland. A replication study population consisting of individuals born preterm (n = 111) and term (n = 197) from southern Finland was also analyzed. Long AR CAG repeats (≥26) were overrepresented and short repeats (≤19) underrepresented in individuals born preterm compared to those born at term. Thus, our linkage and association results emphasize the role of the fetal genome in genetic predisposition to SPTB and implicate AR as a potential novel fetal susceptibility gene for SPTB. 相似文献
44.
Ahlqvist KJ Hämäläinen RH Yatsuga S Uutela M Terzioglu M Götz A Forsström S Salven P Angers-Loustau A Kopra OH Tyynismaa H Larsson NG Wartiovaara K Prolla T Trifunovic A Suomalainen A 《Cell metabolism》2012,15(1):100-109
Somatic stem cell (SSC) dysfunction is typical for different progeroid phenotypes in mice with genomic DNA repair defects. MtDNA mutagenesis in mice with defective Polg exonuclease activity also leads to progeroid symptoms, by an unknown mechanism. We found that Polg-Mutator mice had neural (NSC) and hematopoietic progenitor (HPC) dysfunction already from embryogenesis. NSC self-renewal was decreased in vitro, and quiescent NSC amounts were reduced in vivo. HPCs showed abnormal lineage differentiation leading to anemia and lymphopenia. N-acetyl-L-cysteine treatment rescued both NSC and HPC abnormalities, suggesting that subtle ROS/redox changes, induced by mtDNA mutagenesis, modulate SSC function. Our results show that mtDNA mutagenesis affected SSC function early but manifested as respiratory chain deficiency in nondividing tissues in old age. Deletor mice, having mtDNA deletions in postmitotic cells and no progeria, had normal SSCs. We propose that SSC compartment is sensitive to mtDNA mutagenesis, and that mitochondrial dysfunction in SSCs can underlie progeroid manifestations. 相似文献
45.
Jokela TA Jauhiainen M Auriola S Kauhanen M Tiihonen R Tammi MI Tammi RH 《The Journal of biological chemistry》2008,283(12):7666-7673
We found that d-mannose dose-dependently decreases hyaluronan synthesis in cultured epidermal keratinocytes to approximately 50%, whereas glucose, galactose, and fructose up to 20 mm concentration had no effect. The full inhibition occurred within 3 h following introduction of mannose and did not involve down-regulation of hyaluronan synthase (Has1-3) mRNA. Following introduction of mannose, there was an approximately 50% reduction in the cellular concentration of UDP-N-acetylhexosamines (UDP-HexNAc, i.e. UDP-N-acetylglucosamine and UDP-N-acetylgalactosamine). On the other hand, 2 mm glucosamine in the culture medium increased UDP-HexNAc content, stimulated hyaluronan secretion, and negated the effect of mannose, supporting the notion that the inhibition by mannose on hyaluronan synthesis was because of down-regulated UDP-HexNAc content. The content of UDP-glucuronic acid, the other building block for hyaluronan synthesis, was not reduced by mannose but declined from 39 to 14% of controls by 0.2-1.0 mm 4-methylumbelliferone, another compound that inhibits hyaluronan synthesis. Applying 4-methylumbelliferone and mannose together produced the expected reductions in both UDP sugars but no additive reduction in hyaluronan production, indicating that the concentration of each substrate alone can limit hyaluronan synthesis. Mannose is a potentially useful tool in studies on hyaluronan-dependent cell functions, as demonstrated by reduced rates of keratinocyte proliferation and migration, functions known to depend on hyaluronan synthesis. 相似文献
46.
Ouwehand AC Bergsma N Parhiala R Lahtinen S Gueimonde M Finne-Soveri H Strandberg T Pitkälä K Salminen S 《FEMS immunology and medical microbiology》2008,53(1):18-25
Faecal and serum samples were collected over a period of 6 months from 55 institutionalized elderly subjects, who were enrolled in a double-blind placebo-controlled study. Participants were randomized in one of the three treatment groups: intervention (two probiotic Bifidobacterium longum strains: 2C and 46), placebo and commercial control (Bifidobacterium lactis Bb-12). The faecal Bifidobacterium microbiota was characterized by genus and species-specific PCR. Serum levels of the cytokines IL-10, tumor necrosis factor (TNF)-alpha and transforming growth factor (TGF)-beta1 were determined by enzyme-linked immunosorbent assay. Each participant harboured on average approximately three different bifidobacterial species. The most frequently detected species were B. longum, Bifidobacterium adolescentis and Bifidobacterium bifidum. Depending on the treatment, the intervention resulted in specific changes in the levels of certain Bifidobacterium species, and positive correlations were found between the different species. Negative correlations were observed between the levels of Bifidobacterium species and the pro-inflammatory cytokine TNF-alpha and the regulatory cytokine IL-10. The presence of faecal B. longum and Bifidobacterium animalis correlated with reduced serum IL-10. The anti-inflammatory TGF-beta1 levels were increased over time in all three groups, and the presence of Bifidobacterium breve correlated with higher serum TGF-beta1 levels. This indicates that modulation of the faecal Bifidobacterium microbiota may provide a means of influencing inflammatory responses. 相似文献
47.
Leena Peltonen Piritta Koistinen Milja Karjalainen Antti Häkkinen Jouni Hirvonen 《AAPS PharmSciTech》2002,3(4):52-58
The aim of this study was to formulate nanoparticles from poly(I)lactide by a modified nanoprecipitation method. The main
focus was to study the effect of cosolvent selection on the shape, size, formation efficiency, degree of crystallinity, x-ray
diffraction (XRD) reflection pattern, and zeta potential value of the particles. Low-molecular-weight (2000 g/mol) poly(I)lactide
was used as a polymer, and sodium cromoglycate was used as a drug. Acetone, ethanol, and methanol were selected as cosolvents.
Optimal nanoparticles were achieved with ethanol as a cosolvent, and the formation efficiency of the particles was also higher
with ethanol as compared with acetone or methanol. The particles formulated by ethanol and acetone appeared round and smooth,
while with methanol they were slightly angular. When the volume of the inner phase was decreased during the nanoprecipitation
process, the mean particle size was also decreased with all the solvents, but the particles were more prone to aggregate.
The XRD reflection pattern and the degree of crystallinity were more dependent were more prone to aggregate. The XRD reflection
pattern and the degree of crystallinity were more dependent on the amount of the solvents in the inner phase than on the properties
of the individual cosolvents. The zeta potential values of all the particle batches were slightly negative, which partially
explains the increased tendency toward particle aggregation. 相似文献
48.
Annikki Liakka Hanna Karjalainen Ismo Virtanen Helena Autio-Harmainen 《Cell and tissue research》1995,282(1):117-127
The distribution of the extracellular matrix proteins types III pN-collagen and IV collagen, laminin and tenascin was investigated in fetal, infant, and adult human spleens by using immuno-electron microscopy. The presence of type III pN-collagen was assessed by using an antibody against the aminoterminal propeptide of type III procollagen. All the proteins other than type III pN-collagen were found in reticular fibers throughout development. In the white pulp of the fetus aged 16 gestational weeks, only an occasional type III pN-collagen-containing fibril was present, although type III pN-collagen was abundant in the reticular fibers of the red pulp. Conversely, in adults, most of the reticular fibers of the white pulp, but not of the red pulp, were immunoreactive for type III pN-collagen. Ring fibers, the basement membranes of venous sinuses, were well developed in both infant and adult spleens. The first signs of their formation could be seen as a discontinuous basement membrane, which was immunoreactive for type IV collagen, laminin, and tenascin in the fetus aged 20 gestational weeks. Intracytoplasmic immunoreactivity for all the proteins studied was visible in the mesenchymal cells of the fetus aged 16 gestational weeks and in the reticular cells of the older fetuses, which also showed labeling for type IV collagen and laminin in the endothelial cells. The results suggest that proteins of the extracellular matrix are produced by these stationary cells. 相似文献
49.
In this paper we present a systematic method for generating simulations of nonstationary EEG. Such simulations are needed,
for example, in the evaluation of tracking algorithms. First a state evolution process is simulated. The states are initially
represented as segments of stationary autoregressive processes which are described with the corresponding predictor coefficients
and prediction error variances. These parameters are then concatenated to give a piecewise time-invariant parameter evolution.
The evolution is projected onto an appropriately selected set of smoothly time-varying functions. This projection is used
to generate the final EEG simulation. As an example we use this method to simulate the EEG of a drowsy rat. This EEG can be
described as toggling between two states that differ in the degree of synchronization of the activity-inducing neuron clusters.
Received: 22 June 1994 / Accepted in revised form: 18 February 1997 相似文献
50.
J. Karjalainen H. Auvinen H. Helminen T. J. Arjomäki T. Niva J. Sarvala M. Vilhanen 《Journal of fish biology》2000,56(4):837-857
In 1989–1998, vendace larvae Coregonus albula were sampled in Finnish lakes following a stratified random sampling design. The abundance of young–of–the–year vendace after the first growing season was estimated using catch–per–unit–effort statistics. The number or total area of nursery places hardly limited the recruitment of vendace in the study lakes. The major proportion of prerecruit mortality of vendace occurred in the larval phase and larval sampling produced significant information on young–of–the–year survival. Although larval abundances and recruitment were clearly associated only in Lake Onkamo, generally high larval abundance was needed to produce high number of recruits. 相似文献