搜索结果: 'methocult media formulations for human hematopoietic cells serum containing'

BACKGROUND There have been many randomised trials of adjuvant tamoxifen among women with early breast cancer,and an updated overview of their results is presented. METHODS In 1995,information was sought on each woman in any randomised trial that began before 1990 of adjuvant tamoxifen versus no tamoxifen before recurrence. Information was obtained and analysed centrally on each of 37000 women in 55 such trials,comprising about 87% of the worldwide evidence. Compared with the previous such overview,this approximately doubles the amount of evidence from trials of about 5 years of tamoxifen and,taking all trials together,on events occurring more than 5 years after randomisation. FINDINGS Nearly 8000 of the women had a low,or zero,level of the oestrogen-receptor protein (ER) measured in their primary tumour. Among them,the overall effects of tamoxifen appeared to be small,and subsequent analyses of recurrence and total mortality are restricted to the remaining women (18000 with ER-positive tumours,plus nearly 12000 more with untested tumours,of which an estimated 8000 would have been ER-positive). For trials of 1 year,2 years,and about 5 years of adjuvant tamoxifen,the proportional recurrence reductions produced among these 30000 women during about 10 years of follow-up were 21% (SD 3),29% (SD 2),and 47% (SD 3),respectively,with a highly significant trend towards greater effect with longer treatment (chi2(1)=52.0,2ptextless0.00001). The corresponding proportional mortality reductions were 12% (SD 3),17% (SD 3),and 26% (SD 4),respectively,and again the test for trend was significant (chi2(1) = 8.8,2p=0.003). The absolute improvement in recurrence was greater during the first 5 years,whereas the improvement in survival grew steadily larger throughout the first 10 years. The proportional mortality reductions were similar for women with node-positive and node-negative disease,but the absolute mortality reductions were greater in node-positive women. In the trials of about 5 years of adjuvant tamoxifen the absolute improvements in 10-year survival were 10.9% (SD 2.5) for node-positive (61.4% vs 50.5% survival,2ptextless0.00001) and 5.6% (SD 1.3) for node-negative (78.9% vs 73.3% survival,2ptextless0.00001). These benefits appeared to be largely irrespective of age,menopausal status,daily tamoxifen dose (which was generally 20 mg),and of whether chemotherapy had been given to both groups. In terms of other outcomes among all women studied (ie,including those with ER-poor" tumours)� View Publication

SCOPE Necrotizing enterocolitis (NEC) is a leading cause of morbidity and death in preterm infants,occurring more often in formula-fed than breastfed infants. Studies in both rats and humans show that human milk oligosaccharides (HMOs) lower the incidence of NEC,but the mechanism underlying such protection is currently unclear. METHODS AND RESULTS By extracting HMOs from pooled human breastmilk,the impact of HMOs on the intestinal mucin levels in a murine model of NEC are investigated. To confirm the results,the findings are validated by exposing human intestinal epithelial cells and intestinal organoids to HMOs and evaluated for mucin expression. HMO-gavage to pups increases Muc2 levels and decreases intestinal permeability to macromolecular dextran. HMO-treated cells have increased Muc2 expression,decreased bacterial attachment and dextran permeability during challenge by enteric pathogens. To identify the mediators involved in HMO induction of mucins,it is demonstrated that HMOs directly induce the expression of chaperone proteins including protein disulfide isomerase (PDI). Suppression of PDI activity removes the protective effects of HMOs on barrier function in vitro as well as NEC protection in vivo. CONCLUSIONS Taken together,the results provide insights to the possible mechanisms by which HMOs protect the neonatal intestine through upregulation of mucins. View Publication

PURPOSE To model keratoconus (KC) using induced pluripotent stem cells (iPSC) generated from fibroblasts of both KC and normal human corneal stroma by a viral method. METHODS Both normal and KC corneal fibroblasts from four human donors were reprogramed directly by delivering reprogramming factors in a single virus using 2A self-cleaving" peptides� View Publication

Despite increasing knowledge regarding melanoma-initiating cells (MICs),questions persist regarding the number and phenotypic nature of cells with tumor-generating capability. Evidence for a phenotypically distinct human MIC has been found in NOD/SCID (non-obese diabetic/severe combined immunodeficiency) mice. However,a phenotypically distinct human MIC was not found in the NOD/SCIDIl2rg(-)/(-) (NSG) mouse model. The demonstration of a distinct population of human melanoma cells responsible for tumorigenesis and tumor cell self-renewal would provide an important target for new melanoma therapies. In this study,we show a 100-fold range in MIC frequency in human melanoma (1 in 18,000 to 1 in 1,851,000 cells) in the NOD/SCID mouse. In this model,human melanoma cells with high aldehyde dehydrogenase (ALDH) activity were enriched 16.8-fold in tumorigenic cells over unfractionated (UNF) cells,such that 1 in 21,000 cells was a MIC. In the NSG mouse,the ALDH expressing cell population was enriched 100-fold in tumorigenic cells over UNF cells,such that one in four cells was a MIC. Xenograft melanomas that developed from ALDH(+) cells displayed robust self-renewal,whereas those from ALDH(-) cells showed minimal self-renewal in vitro. Thus,ALDH(+) melanoma cells have enhanced tumorigenicity over ALDH(-) cells and superior self-renewal ability. View Publication

The recent technique of transducing key transcription factors into unipotent cells (fibroblasts) to generate pluripotent stem cells (induced pluripotent stem cells [iPSCs]) has significantly changed the stem cell field. These cells have great promise for many clinical applications,including that of regenerative medicine. Our findings show that iPSCs can be derived from human adipose-derived stromal cells (hASCs),a notable advancement in the clinical applicability of these cells. To investigate differences between two iPS cell lines (fibroblast-iPSC and hASC-iPSC),and also the gold standard human embryonic stem cell,we looked at cell stiffness as a possible indicator of cell differentiation-potential differences. We used atomic force microscopy as a tool to determine stem cell stiffness,and hence differences in material properties between cells. Human fibroblast and hASC stiffness was also ascertained for comparison. Interestingly,cells exhibited a noticeable difference in stiffness. From least to most stiff,the order of cell stiffness was as follows: hASC-iPSC,human embryonic stem cell,fibroblast-iPSC,fibroblasts,and,lastly,as the stiffest cell,hASC. In comparing hASC-iPSCs to their origin cell,the hASC,the reprogrammed cell is significantly less stiff,indicating that greater differentiation potentials may correlate with a lower cellular modulus. The stiffness differences are not dependent on cell culture density; hence,material differences between cells cannot be attributed solely to cell-cell constraints. The change in mechanical properties of the cells in response to reprogramming offers insight into how the cell interacts with its environment and might lend clues to how to efficiently reprogram cell populations as well as how to maintain their pluripotent state. View Publication

Regulatory T cells (Tregs) contribute significantly to the tolerogenic nature of the liver. The mechanisms,however,underlying liver-associated Treg induction are still elusive. We recently identified the vitamin A metabolite,retinoic acid (RA),as a key controller that promotes TGF-β-dependent Foxp3(+) Treg induction but inhibits TGF-β-driven Th17 differentiation. To investigate whether the RA producing hepatic stellate cells (HSC) are part of the liver tolerance mechanism,we investigated the ability of HSC to function as regulatory APC. Different from previous reports,we found that highly purified HSC did not express costimulatory molecules and only upregulated MHC class II after in vitro culture in the presence of exogenous IFN-γ. Consistent with an insufficient APC function,HSC failed to stimulate naive OT-II TCR transgenic CD4(+) T cells and only moderately stimulated α-galactosylceramide-primed invariant NKT cells. In contrast,HSC functioned as regulatory bystanders and promoted enhanced Foxp3 induction by OT-II TCR transgenic T cells primed by spleen dendritic cells,whereas they greatly inhibited the Th17 differentiation. Furthermore,the regulatory bystander capacity of the HSC was completely dependent on their ability to produce RA. Our data thus suggest that HSC can function as regulatory bystanders,and therefore,by promoting Tregs and suppressing Th17 differentiation,they might represent key players in the mechanism that drives liver-induced tolerance. View Publication

Rett syndrome (RTT) is a progressive neurologic disorder representing one of the most common causes of mental retardation in females. To date mutations in three genes have been associated with this condition. Classic RTT is caused by mutations in the MECP2 gene,whereas variants can be due to mutations in either MECP2 or FOXG1 or CDKL5. Mutations in CDKL5 have been identified both in females with the early onset seizure variant of RTT and in males with X-linked epileptic encephalopathy. CDKL5 is a kinase protein highly expressed in neurons,but its exact function inside the cell is unknown. To address this issue we established a human cellular model for CDKL5-related disease using the recently developed technology of induced pluripotent stem cells (iPSCs). iPSCs can be expanded indefinitely and differentiated in vitro into many different cell types,including neurons. These features make them the ideal tool to study disease mechanisms directly on the primarily affected neuronal cells. We derived iPSCs from fibroblasts of one female with p.Q347X and one male with p.T288I mutation,affected by early onset seizure variant and X-linked epileptic encephalopathy,respectively. We demonstrated that female CDKL5-mutated iPSCs maintain X-chromosome inactivation and clones express either the mutant CDKL5 allele or the wild-type allele that serve as an ideal experimental control. Array CGH indicates normal isogenic molecular karyotypes without detection of de novo CNVs in the CDKL5-mutated iPSCs. Furthermore,the iPS cells can be differentiated into neurons and are thus suitable to model disease pathogenesis in vitro. View Publication

Pluripotent stem cells can differentiate into nearly all types of cells in the body. This unique potential provides significant promise for cell-based therapies to restore tissues or organs destroyed by injuries,degenerative diseases,aging,or cancer. The discovery of induced pluripotent stem cell (iPSC) technology offers a possible strategy to generate patient-specific pluripotent stem cells. However,because of concerns about the specificity,efficiency,kinetics,and safety of iPSC reprogramming,improvements or fundamental changes in this process are required before their effective clinical use. A chemical approach is regarded as a promising strategy to improve and change the iPSC process. Dozens of small molecules have been identified that can functionally replace reprogramming factors and significantly improve iPSC reprogramming. In addition to the prospect of deriving patient-specific tissues and organs from iPSCs,another attractive strategy for regenerative medicine is transdifferentiation-the direct conversion of one somatic cell type to another. Recent studies revealed a new paradigm of transdifferentiation: using transcription factors used in iPSC generation to induce transdifferentiation or called iPSC transcription factor-based transdifferentiation. This type of transdifferentiation not only reveals and uses the developmentally plastic intermediates generated during iPSC reprogramming but also produces a wide range of cells,including expandable tissue-specific precursor cells. Here,we review recent progress of small molecule approaches in the generation of iPSCs. In addition,we summarize the new concept of iPSC transcription factor-based transdifferentiation and discuss its application in generating various lineage-specific cells,especially cardiovascular cells. View Publication