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421.
Dr. J. J. Waters M. E. Ferguson-Smith N. Carter J. L. Alexander S. V. Hodgson 《黑龙江环境通报》1990,10(10):677-681
Prenatal diagnosis, by amniocentesis, revealed mosaicism with respect to a bisatellited, apparently dicentric, DA/DAPI positive, de novo marker. The following cell lines were observed in decreasing order of frequency: 46,XX > 48.XX, + mar, + mar » 47,XX, + mar. The pregnancy was terminated and post-mortem examination revealed an apparently normal fetus. Cytogenetic studies of fetal and placental tissues revealed approximately the same level of mosaicism together with the unusual copy number ratio seen in the amniotic fluid cultures. Non-disjunction at the first post-zygotic mitotic division giving rise to a mosaic: 46,XX/ 48,XX, + mar, + mar followed by subsequent mitotic instability of the marker could account for the unusual copy number ratio. 相似文献
422.
Dr. M. L. Whiteford J. Coutts L. Al-Roomi A. Mather G. Lowther A. Cooke J. I. Vaughan G. E. Moore J. L. Tolmie 《黑龙江环境通报》1995,15(6):579-584
We report a growth-retarded infant with congenital heart disease and maternal isodisomy for chromosome 16. Non-mosaic trisomy 16 was detected at mid-trimester chorionic villus sampling, performed because biochemical screening indicated an increased Down's syndrome risk. Further karyotyping analysis of the placenta, after delivery, showed a 50 per cent mosaic trisomy 16. The infant had an atrioventricular (A-V) canal defect, scoliosis, and several minor dysmorphic features. Although uniparental disomy for chromosome 16 has been reported previously, to our knowledge this is the first case of uniparental isodisomy for chromosome 16 which has been investigated with multiple DNA probes. 相似文献
423.
Nicola Rizzo Sandro Gabrielli Gianluigi Pilu Antonella Perolo Alfredo Cacciari Remigio Domini Luciano Bovicelli 《黑龙江环境通报》1987,7(2):109-118
Multicystic dysplastic kidney disease (MDKD) is one of the most common congenital renal anomalies. We report 16 consecutive cases of MDKD recognized in the antenatal period by sonography. Diagnosis is usually easy as MDKD has in the vast majority of cases a striking ultrasound appearance including enlargement of the kidney and multiple renal cysts. However, differentiation from obstructive uropathy may be difficult, and we made a total of five erroneous diagnoses. Unilateral MDKD has almost invariably a good prognosis. However, severe life-threatening associated anomalies were found in six cases. Therefore, a detailed survey of fetal anatomy and determination of karyotype are strongly recommended. 相似文献
424.
The aim of the study was to investigate the rationale of the current indications for fetal chromosome analysis. 5372 women had 5423 amniocenteses performed, this group constituting a consecutive sample at the chromosome laboratory, Rigshospitalet, Copenhagen from March 1973 to September 1980 (Group A + B). Pregnant women 35 years of age, women who previously had a chromosomally abnormal child, families with translocation carriers or other heritable chromosomal disease, families where the father was 50 years or more and women in families with a history of Down's syndrome (group A), were compared to women having amniocentesis, although considered not to have any increased risk of fetal chromosome abnormality (1390 pregnancies, group B). They were also compared with 750 consecutive pregnancies in women 25–34 years of age, in whom all heritable diseases were excluded (group Q. The risk of unbalanced chromosome abnormality in group A (women with elevated risk) is significantly higher than in group B + C (women without elevated risk) (relative risk 2–4). Women with a known familial translocation and women 40 years or more have a relative risk of 5–7 of having an unbalanced chromosome abnormality compared with women without elevated risk. Spontaneous abortion rate and prematurity rate did not differ from rates expected without amniocentesis. It is concluded that current indications may be characterized as a mixture of evident high risk factors and factors with only a minor influence on risk. Indications for amniocentesis should therefore be reconsidered. Because it must be considered impractical and ethically wrong to limit amniocentesis to the two mentioned real high risk groups, and illogical to continue the present policy, which is not based on clearcut evidence, the possibility of offering amniocentesis to all who want it, is discussed. Screening for chromosome disease in all pregnancies is not without problems, but may be reasonable in some localities. 相似文献
425.
It has been postulated that chorionic villi with abundant sprouts have a higher mitotic index and are therefore preferable for obtaining direct chromosome preparations from chorionic villus samples. This theory was tested by correlating villous morphology with mitotic index. Surprisingly, no statistically significant relationship was found. Choice of culture medium, however, was found to be important, with serum-free RPMI yielding a higher mitotic index than 40 per cent FCS in MEM. We conclude that villous morphology, as assessed in this study, is not a major factor in determining the success of direct chromosome preparations. 相似文献
426.
Our aim was to evaluate the potential value of the ratio of the maternal urinary beta-core fragment of human chorionic gonadotropin (βC-hCG) to creatinine (Cr) in discriminating between normal pregnancies and pregnancies associated with fetal chromosomal abnormalities. We hypothesized that pregnancies with fetal chromosomal abnormalities had abnormal quantities of βC-hCG in the urine. The aims of the present study were to investigate retrospectively whether maternal urinary ratios of βC-hCG/Cr are abnormal in women carrying fetuses with chromosome aberrations and to determine normative median values and a reference range for βC-hCG/Cr between 14 and 19 weeks' gestation. Maternal urinary βC-hCG and Cr concentrations were measured in 150 healthy women from 14 to 19 weeks and compared with ten cases of fetal chromosomal abnormalities matched for gestational age. The preliminary cut-off points corresponded to 0·29 multiple of the normal median (MOM) and 2·83 MOM, which were equivalent to the tenth and 90th centiles of the normal range. Of ten cases of fetal chromosomal abnormalities, one out of one (100 per cent) case with trisomy 18 and three of four (75 per cent) cases of variant 9 chromosome had low βC-hCG/Cr (≤0·29 MOM). One of five (20 per cent) cases with Down syndrome had elevated βC-hCG/Cr (≤2·83 MOM). Urinary βC-hCG/Cr ratios obtained in the second trimester may be useful for improved detection efficiency of Down syndrome, trisomy 18, and inversion of chromosome 9. Second-trimester maternal urinary βC-hCG/Cr should be investigated further as a potential marker for fetal chromosome anomalies. 相似文献
427.
Tomás?Landete-CastillejosEmail author Christian?Gortázar Joaquin?Vicente Yolanda?Fierro Andres?Garcia Laureano?Gallego 《Behavioral ecology and sociobiology》2004,57(1):1-8
Several theories predict offspring biases towards males or females with increasing reproductive resources of the mother to maximize reproductive returns by offspring, or as a result of prohibitive cost of the most expensive sex for young mothers or those in poor condition. This study examines foetus sex of 221 harvested hinds in a food-supplemented game estate for 10 years, according to hind age class (yearlings, subadults or adults), precise age, body mass and condition, and jaw length. A logistic model showed that hinds had a greater probability of bearing a male foetus with increasing age class, but not with any other variable. The greatest bias was found in yearling hinds. After controlling for age class and mass, jaw length was smaller in pregnant compared to non-pregnant yearlings and subadults, which suggests a trade-off between reproduction and growth. The bias towards females in yearlings increased as gestation proceeded, which suggests that the bias might be a result of selective abortion of male foetuses. Although results do not exclude an investment in males to increase number of grand-offspring, they suggest that young hinds may produce daughters as a trade-off between low energetic-cost offspring and their need to grow.Communicated by S. Krackow 相似文献
428.
Jean-Francois?VielEmail author Nathalie?Floret Frederic?Mauny 《Environmental and Ecological Statistics》2005,12(3):289-299
Whether general environmental exposures to endocrine disrupting chemicals (including pesticides and dioxin) might induce decreased
sex ratios (male/female ratio at birth) is discussed. To address this issue, the authors looked for a space-time clustering
test which could detect local areas of significantly low risk, assuming a Bernoulli distribution. As a matter of fact, if the endocrine disruptor hypothesis holds true, and if the
sex ratio is a sentinel health event indicative of new reproductive hazards ascribed to environmental factors, then in a given
region, either a cluster of low male/female ratio among newborn babies would be expected in the vicinity of polluting municipal
solid waste incinerators (MSWIs) (supporting the dioxin hypothesis), or local clusters would be expected in some rural areas
where large amounts of pesticides are sprayed.
Among cluster detection tests, the spatial scan statistic has been widely used in various applications to scan for areas
with high rates, and rarely (if ever) with low rates. Therefore, the goal of this paper was to check the properties of the
scan statistics under a given scenario (Bernoulli distribution, search for clusters with low rates) and to assess its added
value in addressing the sex ratio issue.
This study took place in the Franche-Comté region (France), mainly rural, comprising three main MSWIs, among which only one
had high dioxin emissions level in the past. The study population consisted of 192,490 boys and 182,588 girls born during
the 1975–1999 period.
On the whole, the authors conclude that: (i) spatial and space-time scan statistics provide attractive features to address
the sex ratio issue; (ii) sex ratio is not markedly affected across space and does not provide a reliable screening measure
for detecting reproductive hazards ascribed to environmental factors. 相似文献
429.
Abstract: Road mortality has the potential to alter the structure of turtle populations because turtle populations are highly sensitive to additive sources of adult mortality. To address the issue, we captured painted turtles ( Chrysemys picta ; n = 174) and snapping turtles ( Chelydra serpentina ; n = 56) in 18 wetlands surrounded by low road density (≤1.5 km roads/km2 of landscape) and 17 wetlands surrounded by high road density (>1.5 km/km2 ) in central New York in 2002. High road density was associated with male-biased sex ratios in painted turtles (74% vs. 54% males; p = 0.01) and snapping turtles (95% vs. 74% males; p = 0.08), whereas turtle morphology and abundance were not associated with road density. Disproportionate road mortality of females on nesting migrations is the most likely cause of skewed sex ratios. 相似文献
430.
Intra-specific interactions influence egg composition in the lesser black-backed gull (Larus fuscus)
Nanette Verboven Neil P. Evans Liliana D’Alba Ruedi G. Nager Jonathan D. Blount Peter F. Surai Pat Monaghan 《Behavioral ecology and sociobiology》2005,57(4):357-365
Egg composition, which is under maternal control, can have a profound effect on offspring fitness. The presence of maternal testosterone and carotenoids in avian egg yolk, for example, is thought to enhance the development and competitive ability of the offspring and protect the hatching and growing chick against oxidative stress. Egg quality often differs between females and such variation can be due to differences in maternal social environment, e.g. breeding density. However, this is confounded by the possibility that the quality of individuals breeding in high- or low-density areas may vary. We tested if maternal social environment influences egg composition in a colonial seabird, the lesser black-backed gull (Larus fuscus). To control for confounding effects of female quality, we experimentally manipulated maternal social environment during egg formation. We increased the frequency of intra-specific interactions (i.e. aggressive encounters with conspecifics other than nest mates) in which the females were involved, by placing an elevated platform in their territory. Females that took part in more intra-specific interactions produced a heavier last egg, but the yolk testosterone concentration in eggs laid by control and experimental females did not differ. Differences in yolk testosterone concentration in relation to embryo sex were found neither in the control nor in the experimental group. In contrast, within the control group, eggs with a male embryo contained more carotenoids than eggs with a female embryo. Moreover, experimental females that had been involved in more intra-specific interactions produced female eggs with higher carotenoid levels compared to female eggs of control birds. An experimental increase in carotenoid levels was not observed in eggs containing a male embryo. Our results suggest that intra-specific interactions experienced by female birds during egg formation can influence conditions for embryonic development.Communicated by J. Graves 相似文献