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排序方式: 共有283条查询结果,搜索用时 10 毫秒
71.
Human sperm non-nuclear progesterone receptor expression is a novel marker for fertilization outcome 总被引:1,自引:0,他引:1
Jacob A; Hurley I; Mandel FS; Hershlag A; Cooper GW; Benoff S 《Molecular human reproduction》1998,4(6):533-542
In a prospective, blind study, we have examined the relationship among the
expression of human sperm surface progesterone receptors, the ability to
undergo a mannose-stimulated acrosome reaction and the rate of
fertilization in vitro. Individual aliquots of motile spermatozoa were
surface-labelled with progesterone and/or mannose-fluoresceinated ligands.
Spontaneous acrosome loss and the increase in acrosome reactions following
exposure of spermatozoa to mannose ligands were assessed using rhodaminated
Pisum sativum agglutinin. Progesterone fluoresceinated ligand binding was
observed to occur in two patterns: (i) a uniform distribution of labelling
over the acrosome cap (pattern II), and (ii) labelling limited to the
equatorial and postacrosomal regions of the human sperm head (pattern III).
A conversion of pattern II to pattern III binding was observed and was
associated with the acrosome reaction. Pattern III binding was highly
correlated with both fertilization potential and the ability to undergo a
mannose-stimulated acrosome reaction (P < 0.001). In contrast, normal
sperm mannose receptor expression was seen in five men whose abnormal
progesterone receptor expression/function and inability to acrosome react
after mannose treatment were correlated with their reduced fertility in
vitro. In conclusion, surface progesterone receptor aggregation enhances
the mannose ligand-stimulated acrosome reaction. Such detection of
defective sperm surface progesterone receptor expression/function may be
useful in the evaluation and management of male infertility.
相似文献
72.
73.
Bronchopulmonary dysplasia and very low birthweight: Lung function at 11 years of age 总被引:2,自引:0,他引:2
LW DOYLE GW FORD A. OLINSKY AML KNOCHES C. CALLANAN 《Journal of paediatrics and child health》1996,32(4):339-343
Objective : To determine the relationship between lung function at 11 years of age and bronchopulmonary dysplasia (BPD) in very low birthweight (VLBW) children.
Methodology : This study comprised 154 consecutive surviving VLBW children, divided into three groups with respect to their neonatal respiratory morbidity: group I developed BPD; group II required assisted ventilation but did not develop BPD; and group III required no assisted ventilation. Lung function tests were measured on 120/154 (77.9%) children at 11 years of age. The relationship between various lung function variables and neonatal lung disease was analysed by multiple linear regression.
Results : Several lung function variables reflecting airflow were significantly diminished in the BPD group ( n = 15), and residual volume was significantly higher. Despite poorer lung function overall, few children in the BPD group had lung function abnormalities in the clinically significant range ( n = 2 [13.3%] with a forced expired volume in 1 s <75% predicted; n = 2 [13.3%] with a forced vital capacity <75% predicted; n = 1 [6.7%] with a residual volume/total lung capacity >35%). There were no significant differences in lung function variables between group II ( n = 41) and group III ( n = 64). Changes in lung function tests between 8 and 11 years did not vary significantly between the three groups.
Conclusions : VLBW children with BPD in the newborn period have poorer lung function at 11 years of age than other surviving VLBW children without BPD, although few have lung function abnormalities in the clinically significant range. 相似文献
Methodology : This study comprised 154 consecutive surviving VLBW children, divided into three groups with respect to their neonatal respiratory morbidity: group I developed BPD; group II required assisted ventilation but did not develop BPD; and group III required no assisted ventilation. Lung function tests were measured on 120/154 (77.9%) children at 11 years of age. The relationship between various lung function variables and neonatal lung disease was analysed by multiple linear regression.
Results : Several lung function variables reflecting airflow were significantly diminished in the BPD group ( n = 15), and residual volume was significantly higher. Despite poorer lung function overall, few children in the BPD group had lung function abnormalities in the clinically significant range ( n = 2 [13.3%] with a forced expired volume in 1 s <75% predicted; n = 2 [13.3%] with a forced vital capacity <75% predicted; n = 1 [6.7%] with a residual volume/total lung capacity >35%). There were no significant differences in lung function variables between group II ( n = 41) and group III ( n = 64). Changes in lung function tests between 8 and 11 years did not vary significantly between the three groups.
Conclusions : VLBW children with BPD in the newborn period have poorer lung function at 11 years of age than other surviving VLBW children without BPD, although few have lung function abnormalities in the clinically significant range. 相似文献
74.
Dose-dependent localization of TCDD in isolated centrilobular and periportal hepatocytes 总被引:3,自引:1,他引:2
Santostefano MJ; Richardson VM; Walker NJ; Blanton J; Lindros KO; Lucier GW; Alcasey SK; Birnbaum LS 《Toxicological sciences》1999,52(1):9-19
Dose-response relationships for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)
suggest a differential sensitivity of liver cell types to the induction of
cytochrome P450 gene expression, and that the induction of hepatic protein
CYP1A2 causes sequestration of TCDD. In addition, immunolocalization of
hepatic CYP1A1/1B1/1A2 proteins is not uniform after exposure to TCDD. The
mechanism for the regio-specific induction of hepatic P450s by TCDD is
unknown, but may involve the differential distribution of participants in
the AhR-mediated pathway and/or regional P450 isozymes, as well as,
non-uniform distribution/sequestration of TCDD. Therefore, this study
examined the effects of TCDD in unfractionated, centrilobular and
periportal hepatocytes isolated from female Sprague-Dawley rats acutely
exposed (3 days) to a single oral dose of 0.01-10.0 microg [3H]TCDD/kg. A
dose- dependent increase in concentration of TCDD was accompanied by a
dose- dependent increase in CYP1A1, CYP1A2, and CYP1B1 mRNA expression and
associated enzymes in all liver-cell populations. Centrilobular hepatocytes
showed a 2.7- to 4.5-fold higher concentration of TCDD as compared to the
periportal hepatocytes at doses up to 0.3 microg TCDD/kg. Centrilobular
hepatocytes also exhibited an elevated MROD activity as compared to the
periportal hepatocytes at doses up to 0.3 microg TCDD/kg. Furthermore,
centrilobular hepatocytes showed an elevated concentration of induced
CYP1A2 and CYP1B1 mRNA as compared to periportal hepatocytes within the
0.01- and 0.3-microg TCDD/kg- treatment groups. This is the first study to
demonstrate that a dose- dependent difference in distribution of TCDD
exists between centrilobular and periportal cells that might be related to
regional differences in P450 induction.
相似文献
75.
Mooney LA; Bell DA; Santella RM; Van Bennekum AM; Ottman R; Paik M; Blaner WS; Lucier GW; Covey L; Young TL; Cooper TB; Glassman AH; Perera FP 《Carcinogenesis》1997,18(3):503-509
Prior epidemiological evidence suggests that genes controlling the
metabolism of carcinogens and antioxidant/nutritional status are associated
with lung cancer risk, possibly through their ability to modulate DNA
damage by carcinogens. We performed a cross-sectional analysis of 159 heavy
smokers from a cohort of subjects enrolled in a smoking cessation program.
A total of 159 blood samples were analyzed to determine the relative
contributions of genetic polymorphisms [CYP1A1 MspI and exon 7 and
glutathione S-transferase M1 (GSTM1)] and plasma micronutrients to
polycyclic aromatic hydrocarbon-DNA (PAH-DNA) adduct levels. DNA damage in
smokers was affected by genetic polymorphisms and nutritional status.
Smokers with the CYP1A1 exon 7 valine polymorphism had significantly higher
(2-fold, P < or = 0.03) levels of DNA damage than those without. In
parallel models, PAH-DNA adducts were inversely associated with plasma
levels of retinol (beta = -0.93, P = 0.01), beta-carotene (beta = -0.18, P
= 0.09), and alpha- tocopherol (beta = -0.28, P = 0.21) in 159 subjects.
The association between smoking-adjusted plasma beta-carotene levels and
DNA damage was only significant in those subjects lacking the GSTM1
detoxification gene (beta = -0.30, P = 0.05, n = 75). There was a
statistical interaction between beta-carotene and alpha-tocopherol; when
beta- carotene was low, alpha-tocopherol had a significant protective
effect (beta = -0.78, P = 0.04) on adducts, but not when beta-carotene was
high (beta = -0.16, P = 0.57). Plasma alpha-tocopherol was significantly
correlated with beta-carotene (r = 0.36, P = 0.0005) and less strongly with
retinol (r = 0.20, P = 0.0005). These results suggest that several
micronutrients may act in concert to protect against DNA damage and
highlight the importance of assessing overall antioxidant status. In
conclusion, a subset of smokers may be at increased risk of DNA damage and
possibly lung cancer due to the combined effect of low plasma
micronutrients and genetic susceptibility factors. The use of biological
markers to assess efficacy of interventions and to study mechanisms of
micronutrients is timely given the current debate regarding the use of
chemopreventive agents in high risk populations.
相似文献
76.
77.
78.
Gamete donation in assisted reproduction is an accepted treatment option
for certain infertile couples. Traditionally, men donating spermatozoa have
been paid a nominal fee, whilst women donating oocytes have not. The issue
of payment for sperm donors has recently attracted attention following the
Human Fertilisation and Embryology Authority's (HFEA) suggestion that such
payment may be withdrawn. Prior to the final meeting of the HFEA working
party which is examining this issue, here we report the results of a survey
designed to solicit opinion on whether sperm donors should be paid, to
identify social or other factors which influence this opinion, and to
examine the influence of financial incentive on potential donors. We
surveyed 717 individuals in three distinct groups: the general public,
students (potential donors), and infertility patients (potential
recipients). The majority of the potential donor group (students) was in
favour of paying sperm donors, as were infertility patients. In contrast
the general public was not. The opinion of the general public on this issue
was influenced by their prior knowledge of whether donors were paid: those
of the general public favouring the payment of sperm donors had a prior
awareness that such payments were made. Although not in favour of paying
sperm donors, the general public overwhelmingly approved of the use of
donated spermatozoa for the treatment of infertile couples, and thought
that ways should be sought to increase the availability of donor
spermatozoa for the treatment of infertility and for research purposes.
Within the potential donor group (students), the majority indicated that
financial reward was an important factor which would influence their
decision to donate spermatozoa. As the majority of both the potential
recipients and potential donors feels that sperm donors should be paid,
perhaps the views of these groups should carry significant weight when the
decision whether or not to withdraw payment is taken. This is especially
the case in view of the fact that the majority of the general public is in
favour of the use of donated spermatozoa for the treatment of infertile
couples.
相似文献
79.
Jones RJ; Zuehlsdorf M; Rowley SD; Hilton J; Santos GW; Sensenbrenner LL; Colvin OM 《Blood》1987,70(5):1490-1494
We examined the effects of varying incubation conditions on the in vitro activity of 4-hydroperoxycyclophosphamide (4HC). 4HC activity against CFU-GM and against the K562 tumor cell line decreased with increasing the RBC concentration of the incubation mixture. Increasing the concentration of nucleated bone marrow cells in the incubation mixture also decreased the 4HC activity. Evaluation of 53 consecutive patients undergoing autologous bone marrow transplantation (BMT) revealed that the incubation RBC concentration during clinical purging showed a similar effect on CFU-GM recovery. Aldehyde dehydrogenase content of RBCs and nucleated marrow cells appears to be the cause of the inhibition of 4HC activity. Although there was no difference in individual CFU-GM sensitivity to 4HC among normals, previously treated patients undergoing autologous BMT showed significant variability in CFU-GM sensitivity to 4HC. The combined effects of incubation RBC concentration and individual patient 4HC sensitivity appear to account for most of the variability in CFU-GM recovery and speed of hematologic recovery after clinical purging with 4HC. 相似文献
80.