For mammalian spermatozoa to exhibit the ability to bind the zona pellucida （ZP） they must undergo three distinct phases of maturation, namely, spermatogenesis （testis）, epididymal maturation （epididymis） and ca...For mammalian spermatozoa to exhibit the ability to bind the zona pellucida （ZP） they must undergo three distinct phases of maturation, namely, spermatogenesis （testis）, epididymal maturation （epididymis） and capacitation （female reproductive tract）. An impressive array of spermatozoa surface remodeling events accompany these phases of maturation and appear critical for recognition and adhesion of the outer vestments of the oocyte, a structure known as the ZP. It is becoming increasingly apparent that species-specific zona adhesion is not mediated by a single receptor. Instead, compelling evidence now points toward models implicating a multiplicity of receptor-ligand interactions. This notion is in keeping with emerging research that has shown that there is a dynamic aggregation of proteins believed to be important in sperm-ZP recognition to the regions of sperm that mediate this binding event. Such remodeling may in turn facilitate the assembly of a multimeric zona recognition complex （MZRC）. Though formation of MZRCs raises questions regarding the nature of the block to polyspermy, formation and assembly of such a structure would no doubt explain the strenuous maturation process that sperm endure on their sojourn to functional maturity.展开更多
Objective: To determine the content of mitochondrial DNA (mtDNA) in oocytes from a range of patients with fertilization success and failure. Design: Analysis of mtDNA content in fertilized and unfertilized oocytes and...Objective: To determine the content of mitochondrial DNA (mtDNA) in oocytes from a range of patients with fertilization success and failure. Design: Analysis of mtDNA content in fertilized and unfertilized oocytes and embryos by real- time polymerase chain reaction (PCR). Setting: University hospital infertility and research center. Patient(s): Fifty- four women seeking treatment for infertility. Intervention(s): None. Main Outcome Measure(s): A total of 142 fertilized and unfertilized oocytes were classified into three main groups. Group I consisted of 35 fertilized oocytes from 21 patients; group II, 65 unfertilized oocytes from 36 patients; and group III, 42 degenerate oocytes from 23 patients. Mitochondrial DNA content was determined by SYBR Green real- time PCR- based assay. Result(s): The mean mtDNA copy number for the fertilized oocytes was 250,454, whereas for the unfertilized group it was 163,698. There were significant differences for mtDNA copy number between the male factor and female factor infertility unfertilized oocytes and between the unexplained infertility and female factor infertility groups. The mean copy number for the degenerate oocyte group was 44,629, which was significantly different from the other subdivisions in this group. Conclusion(s): Mitochondrial DNA content is critical to fertilization outcome and serves as an important marker of oocyte quality, explaining some cases of fertilization failure.展开更多
Objective To evaluate the relation between sperm count and ejaculatory volume. Methods Semen samples from 1 364 men were collected and ejaculate volume and sperm count were performed. Results A low correlation （11.6%...Objective To evaluate the relation between sperm count and ejaculatory volume. Methods Semen samples from 1 364 men were collected and ejaculate volume and sperm count were performed. Results A low correlation （11.6%） was found but statistically significant （P 〈O.O00 1） and a trend was observed to decrease in the linear regression analysis. In addition, the ejaculate volume was lower in the group with higher sperm count. Conclusion Sperm cells are diluted in the ejaculate volume, for this reason the ejaculates with more volume present less sperm count.展开更多
Background： Sperm DNA fragmentation（sDF） has been proved to be an important parameter in order to predict in vitro the potential fertility of a semen sample. Colloid centrifugation could be a suitable technique to ...Background： Sperm DNA fragmentation（sDF） has been proved to be an important parameter in order to predict in vitro the potential fertility of a semen sample. Colloid centrifugation could be a suitable technique to select those donkey sperm more resistant to DNA fragmentation after thawing. Previous studies have shown that to elucidate the latent damage of the DNA molecule, sDF should be assessed dynamically, where the rate of fragmentation between treatments indicates how resistant the DNA is to iatrogenic damage. The rate of fragmentation is calculated using the slope of a linear regression equation. However, it has not been studied if s DF dynamics fit this model. The objectives of this study were to evaluate the effect of different after-thawing centrifugation protocols on sperm DNA fragmentation and elucidate the most accurate mathematical model（linear regression, exponential or polynomial） for DNA fragmentation over time in frozen-thawed donkey semen.Results： After submitting post-thaw semen samples to no centrifugation（UDC）, sperm washing（SW） or single layer centrifugation（SLC） protocols, sD F values after 6 h of incubation were significantly lower in SLC samples than in SW or UDC.Coefficient of determination（R-2） values were significantly higher for a second order polynomial model than for linear or exponential. The highest values for acceleration of fragmentation（aSDF） were obtained for SW, fol owed by SLC and UDC.Conclusion： SLC after thawing seems to preserve longer DNA longevity in comparison to UDC and SW. Moreover,the fine-tuning of models has shown that sDF dynamics in frozen-thawed donkey semen fit a second order polynomial model, which implies that fragmentation rate is not constant and fragmentation acceleration must be taken into account to elucidate hidden damage in the DNA molecule.展开更多
Objective: To describe fetal growth centiles in relation tomaternal malaria a nd HIV status, using cross sectional measurements at birth. Design: A cross sect ional study of pregnant women and their babies. Data on ma...Objective: To describe fetal growth centiles in relation tomaternal malaria a nd HIV status, using cross sectional measurements at birth. Design: A cross sect ional study of pregnant women and their babies. Data on maternal socioeconomic s tatus and current pregnancy, including HIV status and newborn anthropometry, wer e collected. Malaria parasitaemia was assessed in maternal peripheral and placen tal blood, fetal haemoglobin was measured in cord blood, and maternal HIV status was determined. Setting: Two district hospitals in rural southern Malawi, betwe en March 1993 and July 1994. Outcome variables: Newborn weight, length, Rohrer s ponderal index. Results: Maternal HIV (adjusted odds ratio (AOR) 1.76 (95% confidence interval 1.04 to 2.98)) and first pregnancy (AOR 1.83 (1.10 to 3.05)) were independently associated with low weight for age. Placental or peripheral parasifaemia at delivery (AOR 1.73 (1.02 to 2.88)) and primigravidae (AOR 2.13 ( 1.27 to 3.59)) were independently associated with low length for age. Maternal m alaria at delivery and primiparity were associated with reduced newborn weight a nd length but not with disproportionate growth. Maternal HIV infection was assoc iated only with reduced birth weight. The malaria and parity effect occurred thr oughout gestational weeks 30- 40, but the HIV effect primarily after 38 weeks g estation. Conclusion: Fetal growth retardation in weight and length commonly occ urs in this highly malarious area and is present from 30 weeks gestation. A mate rnal HIV effect on fetal weight occurred after 38 weeks gestation.展开更多
The efficiency of transplacental transfer of measles specific antibody was assessed in relation to placental malaria. Infection at delivery was associated with a 30%decrease in expected cord measles antibody titres. U...The efficiency of transplacental transfer of measles specific antibody was assessed in relation to placental malaria. Infection at delivery was associated with a 30%decrease in expected cord measles antibody titres. Uninfected women who received anti-malarial drugs during pregnancy transmitted 30%more antibody than those who received no anti-malarial drugs.展开更多
Objective: To highlight the differences in mode of delivery between women augmented with intravenous oxytocin because of failure to progress in labour with those who labour without the need for augmentation. Study des...Objective: To highlight the differences in mode of delivery between women augmented with intravenous oxytocin because of failure to progress in labour with those who labour without the need for augmentation. Study design: An incidence study over a 5-year-period in a tertiary referral hospital comparing 1097 nulliparous women who were augmented in labour with 2745 nulliparous women who did not need augmentation. Only labours of spontaneous onset in the pregnancies of women at term were studied. The incidence of pregnancy outcomes were assessed by presenting estimates of relative risk (RR) and their 95%confidence intervals (CI). Results: Only 51.1%of women who received augmentation achieved a normal vaginal delivery compared with 76.5%of women who did not need augmentation (RR 0.67; CI 0.63-0.71). Contributory factors to this disparity included a greater number of Caesarean sections (14.4%versus 6.6%; RR 2.18 CI 1.74-2.67), forcep deliveries (12.8%versus 5.3%; RR 2.41 CI 1.93-3.01) and ventouse deliveries (21.7%versus 11.5%; RR 1.89 CI 1.62-2.21) being performed among augmented labours as compared to normal progressive labours. Conclusion: Significant improvements in the management of labours which fail to progress are needed if normal vaginal delivery rates are to approach those seen in labours which progress without the need for augmentation.展开更多
Background: The concomitant use of fractal and Euclidian measurements has led to the development of new methodologies of cell evaluation, including a diagnosis of cervical cells that set up differences between normali...Background: The concomitant use of fractal and Euclidian measurements has led to the development of new methodologies of cell evaluation, including a diagnosis of cervical cells that set up differences between normality and various degrees of lesion, to carcinoma. Aim: To confirm the diagnostic capacity of the methodology based on fractal and Euclidian geometry for the mathematical diagnosis through a blind study of normal cells and with different types of lesion, as atypia of undetermined significance (ASCUS), low grade squamous intra-epithelial lesion (LGSIL) and high grade squamous intra-epithelial lesion (HGSIL). Methods: 100 cells of Papanicolaou tests were analyzed and divided into 4 groups according to conventional parameters: 25 normal, 25 ASCUS, 25 LGSIL and 25 HGSIL. By means of the Box-counting Fractal Space, we calculated the fractal dimension and occupying spaces of the border and surface in pixels of the cell nucleus and cytoplasm. The diagnostic parameters of the previously developed methodology were applied and compared with the conventional diagnosis, setting up sensibility, specificity, negative likelihood ratio and Kappa coefficient. Results: The values of the occupation of the border and surface of the cell nucleus and cytoplasm were consistent with the values found by the diagnostic methodology previously found. The subtraction of the nucleus and cytoplasm frontiers presented values between: 189 and 482 for normality;159 and 432 for ASCUS;126 to 401 for LGSIL and 39 to 122 for HGSIL. A sensitivity and specificity of 100%, and a Kappa coefficient of 1 were obtained. Conclusions: The capacity of the methodology to diagnose quantitatively the different stages in the evolution of the cervical cells observed in Papanicolaou tests was confirmed, from normality to HGSIL.展开更多
Natural illumination conditions are highly variable and because of their sessile life style, plants are forced to acclimate to them at the cellular and molecular level. Changes in light intensity or quality induce cha...Natural illumination conditions are highly variable and because of their sessile life style, plants are forced to acclimate to them at the cellular and molecular level. Changes in light intensity or quality induce changes in the reduction/oxidation （redox） state of the photosynthetic electron chain that acts as a trigger for compen- satory acclimation responses comprising functional and structural adjustments of photosynthesis and metabolism. Such responses include redox-controlled changes in plant gene expression in the nucleus and organelles. Here we describe a strategy for the identification of early redox-regulated genes （ERGs） in the nucleus of the model organism Arabidopsis thaliana that respond significantly 30 or 60 min after the generation of a reduction signal in the photosynthetic electron transport chain. By comparing the response of wild-type plants with that of the acclimation mutant stn7, we could specifically identify ERGs. The results reveal a significant impact of chloroplast redox signals on distinct nuclear gene groups including genes for the mitochondrial electron transport chain, tetrapyrrole biosynthesis, carbohydrate metabolism, and signaling lipid synthesis. These expression profiles are clearly different from those observed in response to the reduction of photosynthetic electron transport by high light treatments. Thus, the ERGs identified are unique to redox imbalances in photosynthetic electron transport and were then used for analyzing potential redox-responsive cis-elements, trans-factors, and chromosomal regulatory hot spots. The data identify a novel redox-responsive element and indicate extensive redox control at transcriptional and chromosomal levels that point to an unprecedented impact of redox signals on epigenetic processes.展开更多
文摘For mammalian spermatozoa to exhibit the ability to bind the zona pellucida （ZP） they must undergo three distinct phases of maturation, namely, spermatogenesis （testis）, epididymal maturation （epididymis） and capacitation （female reproductive tract）. An impressive array of spermatozoa surface remodeling events accompany these phases of maturation and appear critical for recognition and adhesion of the outer vestments of the oocyte, a structure known as the ZP. It is becoming increasingly apparent that species-specific zona adhesion is not mediated by a single receptor. Instead, compelling evidence now points toward models implicating a multiplicity of receptor-ligand interactions. This notion is in keeping with emerging research that has shown that there is a dynamic aggregation of proteins believed to be important in sperm-ZP recognition to the regions of sperm that mediate this binding event. Such remodeling may in turn facilitate the assembly of a multimeric zona recognition complex （MZRC）. Though formation of MZRCs raises questions regarding the nature of the block to polyspermy, formation and assembly of such a structure would no doubt explain the strenuous maturation process that sperm endure on their sojourn to functional maturity.
文摘Objective: To determine the content of mitochondrial DNA (mtDNA) in oocytes from a range of patients with fertilization success and failure. Design: Analysis of mtDNA content in fertilized and unfertilized oocytes and embryos by real- time polymerase chain reaction (PCR). Setting: University hospital infertility and research center. Patient(s): Fifty- four women seeking treatment for infertility. Intervention(s): None. Main Outcome Measure(s): A total of 142 fertilized and unfertilized oocytes were classified into three main groups. Group I consisted of 35 fertilized oocytes from 21 patients; group II, 65 unfertilized oocytes from 36 patients; and group III, 42 degenerate oocytes from 23 patients. Mitochondrial DNA content was determined by SYBR Green real- time PCR- based assay. Result(s): The mean mtDNA copy number for the fertilized oocytes was 250,454, whereas for the unfertilized group it was 163,698. There were significant differences for mtDNA copy number between the male factor and female factor infertility unfertilized oocytes and between the unexplained infertility and female factor infertility groups. The mean copy number for the degenerate oocyte group was 44,629, which was significantly different from the other subdivisions in this group. Conclusion(s): Mitochondrial DNA content is critical to fertilization outcome and serves as an important marker of oocyte quality, explaining some cases of fertilization failure.
基金Universidad de Antioquia supported this work and Walter Cardona Maya was supported by a fellowship from Colciencias, Colombia
文摘Objective To evaluate the relation between sperm count and ejaculatory volume. Methods Semen samples from 1 364 men were collected and ejaculate volume and sperm count were performed. Results A low correlation （11.6%） was found but statistically significant （P 〈O.O00 1） and a trend was observed to decrease in the linear regression analysis. In addition, the ejaculate volume was lower in the group with higher sperm count. Conclusion Sperm cells are diluted in the ejaculate volume, for this reason the ejaculates with more volume present less sperm count.
基金partially supported by grants RZ2009-00006-00-00(Instituto Nacional de Investigacion y Tecnología Agraria y Alimentaria,Ministerio de Ciencia e Innovación,Spain)AGL-2013-42726-R(Secretaria de Estado de Investigacion,Desarrollo e Innovacion,Ministerio de Economia y Competitividad,Spain)+1 种基金supported by a Ph.D.fellowship from the ceiA3(Andalucia,Spain)with funding provided by Banco Santander through its Global Division,Santander Universidadesfunded by the Swedish Foundation for Equine Research,Stockholm,Sweden(H14-47-008)
文摘Background： Sperm DNA fragmentation（sDF） has been proved to be an important parameter in order to predict in vitro the potential fertility of a semen sample. Colloid centrifugation could be a suitable technique to select those donkey sperm more resistant to DNA fragmentation after thawing. Previous studies have shown that to elucidate the latent damage of the DNA molecule, sDF should be assessed dynamically, where the rate of fragmentation between treatments indicates how resistant the DNA is to iatrogenic damage. The rate of fragmentation is calculated using the slope of a linear regression equation. However, it has not been studied if s DF dynamics fit this model. The objectives of this study were to evaluate the effect of different after-thawing centrifugation protocols on sperm DNA fragmentation and elucidate the most accurate mathematical model（linear regression, exponential or polynomial） for DNA fragmentation over time in frozen-thawed donkey semen.Results： After submitting post-thaw semen samples to no centrifugation（UDC）, sperm washing（SW） or single layer centrifugation（SLC） protocols, sD F values after 6 h of incubation were significantly lower in SLC samples than in SW or UDC.Coefficient of determination（R-2） values were significantly higher for a second order polynomial model than for linear or exponential. The highest values for acceleration of fragmentation（aSDF） were obtained for SW, fol owed by SLC and UDC.Conclusion： SLC after thawing seems to preserve longer DNA longevity in comparison to UDC and SW. Moreover,the fine-tuning of models has shown that sDF dynamics in frozen-thawed donkey semen fit a second order polynomial model, which implies that fragmentation rate is not constant and fragmentation acceleration must be taken into account to elucidate hidden damage in the DNA molecule.
文摘Objective: To describe fetal growth centiles in relation tomaternal malaria a nd HIV status, using cross sectional measurements at birth. Design: A cross sect ional study of pregnant women and their babies. Data on maternal socioeconomic s tatus and current pregnancy, including HIV status and newborn anthropometry, wer e collected. Malaria parasitaemia was assessed in maternal peripheral and placen tal blood, fetal haemoglobin was measured in cord blood, and maternal HIV status was determined. Setting: Two district hospitals in rural southern Malawi, betwe en March 1993 and July 1994. Outcome variables: Newborn weight, length, Rohrer s ponderal index. Results: Maternal HIV (adjusted odds ratio (AOR) 1.76 (95% confidence interval 1.04 to 2.98)) and first pregnancy (AOR 1.83 (1.10 to 3.05)) were independently associated with low weight for age. Placental or peripheral parasifaemia at delivery (AOR 1.73 (1.02 to 2.88)) and primigravidae (AOR 2.13 ( 1.27 to 3.59)) were independently associated with low length for age. Maternal m alaria at delivery and primiparity were associated with reduced newborn weight a nd length but not with disproportionate growth. Maternal HIV infection was assoc iated only with reduced birth weight. The malaria and parity effect occurred thr oughout gestational weeks 30- 40, but the HIV effect primarily after 38 weeks g estation. Conclusion: Fetal growth retardation in weight and length commonly occ urs in this highly malarious area and is present from 30 weeks gestation. A mate rnal HIV effect on fetal weight occurred after 38 weeks gestation.
文摘The efficiency of transplacental transfer of measles specific antibody was assessed in relation to placental malaria. Infection at delivery was associated with a 30%decrease in expected cord measles antibody titres. Uninfected women who received anti-malarial drugs during pregnancy transmitted 30%more antibody than those who received no anti-malarial drugs.
文摘Objective: To highlight the differences in mode of delivery between women augmented with intravenous oxytocin because of failure to progress in labour with those who labour without the need for augmentation. Study design: An incidence study over a 5-year-period in a tertiary referral hospital comparing 1097 nulliparous women who were augmented in labour with 2745 nulliparous women who did not need augmentation. Only labours of spontaneous onset in the pregnancies of women at term were studied. The incidence of pregnancy outcomes were assessed by presenting estimates of relative risk (RR) and their 95%confidence intervals (CI). Results: Only 51.1%of women who received augmentation achieved a normal vaginal delivery compared with 76.5%of women who did not need augmentation (RR 0.67; CI 0.63-0.71). Contributory factors to this disparity included a greater number of Caesarean sections (14.4%versus 6.6%; RR 2.18 CI 1.74-2.67), forcep deliveries (12.8%versus 5.3%; RR 2.41 CI 1.93-3.01) and ventouse deliveries (21.7%versus 11.5%; RR 1.89 CI 1.62-2.21) being performed among augmented labours as compared to normal progressive labours. Conclusion: Significant improvements in the management of labours which fail to progress are needed if normal vaginal delivery rates are to approach those seen in labours which progress without the need for augmentation.
文摘Background: The concomitant use of fractal and Euclidian measurements has led to the development of new methodologies of cell evaluation, including a diagnosis of cervical cells that set up differences between normality and various degrees of lesion, to carcinoma. Aim: To confirm the diagnostic capacity of the methodology based on fractal and Euclidian geometry for the mathematical diagnosis through a blind study of normal cells and with different types of lesion, as atypia of undetermined significance (ASCUS), low grade squamous intra-epithelial lesion (LGSIL) and high grade squamous intra-epithelial lesion (HGSIL). Methods: 100 cells of Papanicolaou tests were analyzed and divided into 4 groups according to conventional parameters: 25 normal, 25 ASCUS, 25 LGSIL and 25 HGSIL. By means of the Box-counting Fractal Space, we calculated the fractal dimension and occupying spaces of the border and surface in pixels of the cell nucleus and cytoplasm. The diagnostic parameters of the previously developed methodology were applied and compared with the conventional diagnosis, setting up sensibility, specificity, negative likelihood ratio and Kappa coefficient. Results: The values of the occupation of the border and surface of the cell nucleus and cytoplasm were consistent with the values found by the diagnostic methodology previously found. The subtraction of the nucleus and cytoplasm frontiers presented values between: 189 and 482 for normality;159 and 432 for ASCUS;126 to 401 for LGSIL and 39 to 122 for HGSIL. A sensitivity and specificity of 100%, and a Kappa coefficient of 1 were obtained. Conclusions: The capacity of the methodology to diagnose quantitatively the different stages in the evolution of the cervical cells observed in Papanicolaou tests was confirmed, from normality to HGSIL.
文摘Natural illumination conditions are highly variable and because of their sessile life style, plants are forced to acclimate to them at the cellular and molecular level. Changes in light intensity or quality induce changes in the reduction/oxidation （redox） state of the photosynthetic electron chain that acts as a trigger for compen- satory acclimation responses comprising functional and structural adjustments of photosynthesis and metabolism. Such responses include redox-controlled changes in plant gene expression in the nucleus and organelles. Here we describe a strategy for the identification of early redox-regulated genes （ERGs） in the nucleus of the model organism Arabidopsis thaliana that respond significantly 30 or 60 min after the generation of a reduction signal in the photosynthetic electron transport chain. By comparing the response of wild-type plants with that of the acclimation mutant stn7, we could specifically identify ERGs. The results reveal a significant impact of chloroplast redox signals on distinct nuclear gene groups including genes for the mitochondrial electron transport chain, tetrapyrrole biosynthesis, carbohydrate metabolism, and signaling lipid synthesis. These expression profiles are clearly different from those observed in response to the reduction of photosynthetic electron transport by high light treatments. Thus, the ERGs identified are unique to redox imbalances in photosynthetic electron transport and were then used for analyzing potential redox-responsive cis-elements, trans-factors, and chromosomal regulatory hot spots. The data identify a novel redox-responsive element and indicate extensive redox control at transcriptional and chromosomal levels that point to an unprecedented impact of redox signals on epigenetic processes.
