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41.
Amaral IF Lamghari M Sousa SR Sampaio P Barbosa MA 《Journal of biomedical materials research. Part A》2005,75(2):387-397
Cell adhesion, migration, and proliferation of a few anchorage-dependent cells cultured on chitosan (Ch) matrices are influenced by the degree of N-acetylation (DA) of Ch. In the present work, we examined the influence of the DA on the attachment, spreading, proliferation, and osteogenic differentiation of rat bone marrow stromal cells (rBMSCs). Ch membranes were characterized in terms of surface morphology, roughness, and wettability, and in terms of adsorption of an adhesive protein, fibronectin (Fn). Chs with DAs in the range of 4 to 49% were used. Among the Ch samples, the DA of 4% led to the highest Fn surface concentration, both from single protein solution and from diluted serum. Furthermore, the levels of Fn adsorbed from serum found for this DA were threefold higher than for the tissue culture polystyrene control, indicating that in the presence of competitive proteins Ch is more specific toward Fn adsorption than tissue culture polystyrene. rBMSCs cultured on Ch carrying a DA of 4% were able to spread, proliferate, and differentiate, reaching a higher level of osteogenic differentiation than on the control, despite the lower cell attachment observed for all Ch samples. Because the Ch sample with a DA of 4% showed the highest Fn adsorption from serum, we suggest that cell adhesion, spreading, and osteogenic differentiation of rBMSCs on Ch may be mediated by the adsorbed layer of Fn. 相似文献
42.
Silviene Fabiana De Oliveira Eliane Barbosa Dos Santos Patrícia Jeanne De Souza Mendona Daniela Cristiane Da Cruz Rocha Sidney Emanuel Batista Dos Santos 《American journal of human biology》2001,13(6):718-720
The group‐specific component (GC) system is of interest in anthropological genetic studies because the distribution of its subtypes distinguishes among major ethnic groups. The GC system was analyzed in Curiaú and Pacoval, two remnant Quilombo populations (African‐derived populations) from the Brazilian Amazon. There was no significant statistical difference in allelic frequencies between the two populations or between them and three other African‐derived Brazilian populations (Mimbó, Sítio Velho, and Gaucinha in Northeastern Brazil). These populations share similarities among themselves and with African populations (high frequencies of GC*1F and lower frequencies of GC*1S), which may reflect the influence of a high level of African contribution to their formation, but there is a clear difference between them and Europeans and South American Indians. It is suggested that the GC system is a useful marker for studying relationships between single populations and major ethnic groups, but does not discriminate between populations which share the same parental stock. Am. J. Hum. Biol. 13:718–720, 2001. © 2001 Wiley‐Liss, Inc. 相似文献
43.
Hydrosalpinges adversely affect markers of endometrial receptivity 总被引:22,自引:10,他引:22
Meyer WR; Castelbaum AJ; Somkuti S; Sagoskin AW; Doyle M; Harris JE; Lessey BA 《Human reproduction (Oxford, England)》1997,12(7):1393-1398
While in-vitro fertilization (IVF) was initially developed in women with
tubal factor infertility, recent clinical studies have suggested that the
presence of hydrosalpinges lowers implantation and pregnancy rates. We
postulated that these hydrosalpinges cause impaired endometrial
receptivity. A total of 103 women with hydrosalpinges were prospectively
evaluated, and compared with 55 infertile and 44 fertile controls. All
women had endometrial biopsies during the window of implantation, analysed
by conventional histological criteria, and also stained for three integrin
markers of endometrial receptivity (alpha1beta1, alpha4beta1 and alpha
vbeta3). Women with hydrosalpinges (cases) expressed significantly less of
the alpha vbeta3 integrin compared with controls. There was no difference
in expression of alpha1beta1 or alpha4beta1 among groups. A significantly
greater number of cases had out of phase histology and missing alpha vbeta3
(type I defects) and absent integrin expression despite normal histological
maturation (type II) defects, compared with controls. Of 20 women with
impaired endometrial receptivity who were also biopsied after hydrosalpinx
surgery, 70% demonstrated increased alpha vbeta3 expression. Seventy-seven
percent of type I and 57% of type II defects were corrected
postoperatively. Using markers of endometrial receptivity, this study
demonstrates that inflammatory hydrosalpinges have an adverse effect on
endometrial receptivity, which in some cases may be overcome by surgical
treatment of the hydrosalpinx.
相似文献
44.
采用生物素结合的葡聚糖胺顺行示踪法研究了大鼠视皮质主要胼胝体投射区即17/18a交界区胼胝体轴突的生后发育和形态。在生后5天时,此交界区胼胝体轴突从白质向灰质Ⅰ层垂直生长,在灰质内仅有极少量的侧支抽芽。至生后13天时,皮质Ⅰ层最先出现致密的由胼胝体轴突终支组成的终末丛。到生后17天时,类似的终末丛也见于皮质Ⅱ/Ⅲ,Ⅴ和Ⅵ层,这种分布型式与成年大鼠者相似。以上结果表明,绝大部分胼胝体轴突首先生长到达Ⅰ层并先在Ⅰ层发出终支,然后再在其它皮质层发出侧支及终支,因而提示皮质Ⅰ层在胼胝体联系的生后发育中可能发挥重要作用。 相似文献
45.
Schover LR; Thomas AJ; Falcone T; Attaran M; Goldberg J 《Human reproduction (Oxford, England)》1998,13(4):862-866
Many couples undergoing in-vitro fertilization (IVF) are at a higher risk
of having a child with a genetic abnormality. In a sample of 55 consecutive
couples starting IVF, only 33% had no genetic risk factor. The most common
genetic risks were advanced maternal age and possible abnormalities
associated with severe male infertility. Despite education on these risks,
71% of couples had no interest in receiving formal genetic counselling.
Only 14% of couples at risk would consider using a gamete donor to avoid
transmitting a genetic disorder to a child. The triple test to screen for
fetal abnormalities was acceptable to 82% of couples, but only 47% planned
to have amniocentesis or chorionic villi sampling. Couples were
significantly more likely to opt for prenatal testing if they would
consider terminating a pregnancy should the fetus have a severe genetic
abnormality (P < 0.01). Roman Catholic couples tended to have more
conservative attitudes about pregnancy termination. Socio-economic status
and whether the infertility factor was male or female were not predictors
of a couple's attitudes.
相似文献
46.
Optimization of a method for deactivation of platelet-activating factor:acetylhydrolase in serum for use in in-vitro fertilization culture media 总被引:1,自引:0,他引:1
Embryos produced by in-vitro fertilization (IVF) may produce less
platelet-activating factor (PAF) than is optimal for development. It was
previously shown that supplementation of culture media with PAF results in
a significant increase in pregnancy rate. Human embryos are often cultured
in media supplemented with serum containing the enzyme PAF:acetylhydrolase
(PAF:AH; EC 3.1.1.47), which hydrolyses PAF to its inactive form, lyso-PAF.
Thus, effective supplementation of media with PAF requires inactivation of
this enzyme. In this study we examine the efficacy of the methods of PAF:AH
deactivation used for PAF supplementation of IVF culture medium. When the
effectiveness of a commonly used acid treatment protocol (pH 3.0 at room
temperature for 5 min) was examined, it was found that it was not
completely effective for the majority of sera. When synthetic PAF was added
to 18 serum samples which had been acid treated, five had 90-100% of the
original PAF remaining after 24 h (showing that the acid treatment was
effective), eight had from 10-90% of the original PAF remaining after 24 h,
and five samples had 0-10%. The extent to which PAF:AH was susceptible to
deactivation was not associated with the activity in the serum prior to
treatment, the serum oestradiol concentration, or the cause of infertility.
The period of acidification and the incubation temperature were assessed to
develop a new acid-treatment protocol (20 min acid treatment at 37 degrees
C) which was able to deactivate PAF:AH effectively in all sera (53/53)
examined. A trial was performed to assess the effect of acid treatment of
serum for 5 min at room temperature compared with the new protocol (20 min
at 37 degrees C) on IVF outcome, following PAF supplementation of IVF
culture medium. Oocyte recovery, fertilization and embryo development rates
were equivalent for both groups and approximately equal numbers of embryos
were transferred or cryopreserved. Pregnancy rates were not significantly
different (14.6 versus 20.0%) for the two treatments, with a trend towards
a higher pregnancy rate with the new acid- treatment protocol. The results
show that this new procedure for acid treatment of serum in combination
with PAF supplementation does not have detrimental effects on embryos and
their pregnancy outcome and is therefore suitable for use in IVF.
相似文献
47.
Positional cloning of the gene for X-linked retinitis pigmentosa 3: homology with the guanine-nucleotide-exchange factor RCC1 总被引:6,自引:7,他引:6
Roepman R; van Duijnhoven G; Rosenberg T; Pinckers AJ; Bleeker-Wagemakers LM; Bergen AA; Post J; Beck A; Reinhardt R; Ropers HH; Cremers FP; Berger W 《Human molecular genetics》1996,5(7):1035-1041
The gene for retinitis pigmentosa 3 (RP3), the most frequent form of X-
linked RP (XLRP), has been mapped previously to a chromosome interval of
less than 1000 kbp between the DXS1110 marker and the OTC locus at
Xp21.1-p11.4. Employing a novel technique, YAC Representation Hybridization
(YRH)', we have recently identified a small XLRP associated microdeletion
in this interval, as well as several putative exons including the 3' end of
a gene that was truncated by the deletion. cDNA library screening and
sequencing of a cosmid centromeric to the deletion has now enabled us to
identify numerous additional exons and to detect several point mutations in
patients with XLRP. The predicted gene product shows homology to RCC1, the
guanine-nucleotide- exchange factor (GEF) of the Ras-like GTPase Ran. Our
findings suggest that we have cloned the long-sought RP3 gene, and that it
may encode the GEF of a retina-specific GTP-binding protein.
相似文献
48.
Burwinkel B; Maichele AJ; Aagenaes O; Bakker HD; Lerner A; Shin YS; Strachan JA; Kilimann MW 《Human molecular genetics》1997,6(7):1109-1115
Glycogen storage disease due to phosphorylase kinase deficiency occurs in
several variants that differ in mode of inheritance and tissue-
specificity. This heterogeneity is suspected to be largely due to mutations
affecting different subunits and isoforms of phosphorylase kinase. The gene
of the ubiquitously expressed beta subunit, PHKB, was a candidate for
involvement in autosomally transmitted phosphorylase kinase deficiency of
liver and muscle. To identify such mutations, the complete PHKB coding
sequence was amplified by RT-PCR of RNA isolated from blood samples of
patients and analyzed by direct sequencing of PCR products. The
characterization of mutations was complemented by PCR of genomic DNA. In
one female and four male patients, we identified five independent nonsense
mutations (Y418ter; R428ter; Y974H+E975ter; Q656ter in two cases), one
single-base insertion in codon N421, one splice-site mutation affecting
exon 31, and a large deletion involving the loss of exon 8. Although these
severe translation-disrupting mutations occur in constitutively expressed
sequences of the only known beta subunit gene of phosphorylase kinase,
PHKB, they are associated with a surprisingly mild clinical phenotype,
affecting virtually only the liver, and relatively high residual enzyme
activity of approximately 10%.
相似文献
49.
The t(X;1)(p11.2;q21.2) translocation in papillary renal cell carcinoma fuses a novel gene PRCC to the TFE3 transcription factor gene 总被引:4,自引:2,他引:4
50.
Barrias CC Ribeiro CC Lamghari M Miranda CS Barbosa MA 《Journal of biomedical materials research. Part A》2005,72(1):57-66
In this study, the behavior of bone marrow stromal cells cultured on calcium titanium phosphate (CTP) microspheres was analyzed. Cell adhesion and proliferation were estimated by the neutral red assay and by total DNA quantification. Morphology and deposition of extracellular matrix were assessed by confocal laser scanning microscopy and/or scanning electron microscopy. The expression of the osteoblastic phenotype was evaluated by monitoring alkaline phosphatase activity and osteocalcin secretion. Results revealed that cells were able to attach and spread on the surface of CTP microspheres, and gradually grow into nearly confluent monolayers. Moreover, cells were able to bridge adjacent microspheres forming microsphere-cell clusters. Cells produced an abundant amount of fibrillar extracellular matrix that covered the substrate surface. Alkaline phosphatase activity peaked around days 7-14 and then decreased until day 21. Cells secreted osteocalcin, with higher levels being detected at day 14 than at day 21. Taken together, these results suggest that CTP microspheres are appropriate scaffolds for the growth and differentiation of cells along the osteoblastic lineage. 相似文献