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1.
The growth and reproductive development of the male tree shrew were studied from birth to sexual maturity. An infantile phase from birth to Day 30 was characterized by the rapid involution of the testis and adrenal gland from a fetal condition followed by a nadir in testosterone levels and slow growth and differentiation of the testis and accessory sex organs. The initiation of puberty occurred collaterally with the emergence of the young from the nest and was marked by a sharp rise in testosterone levels from Days 30 to 35 to maximum levels at Days 40-55. Peak testosterone levels were temporally correlated with the onset of maximum growth and differentiation of the testis and accessory sex organs, descent of the testis, development of the scrotum, and a pronounced peak in the weight-velocity curve. The rapid growth of males at puberty contributed to a moderate degree of sexual dimorphism in this species. Puberty was attained at about Day 90 with the completion of spermatogenesis and the functional differentiation of the accessory sex organs. The postnatal development of the tree shrew conforms with the general primate pattern. The precise endocrine correlates established during puberty make Tupaia belangeri a useful small animal model for the study of puberty in primates.  相似文献   

2.
The reproductive tracts of 26 estrus synchronized, bred ewes were scanned with a portable 5.0 MHz real-time ultrasound unit within 1 to 6 d postbreeding. Intrarectal scanning was performed on alternate days until Days 28 to 30 and twice weekly until Days 50 of gestation. Transabdominal uterine scans were conducted twice weekly from Days 25 to 65 and continued weekly until parturition. A total of 24 ewes (92%) became pregnant. A nonpregnant ewe was recognized 100% of the time by both methods of ultrasonic screening. Correct identification of a gravid ewe as pregnant was 100% from Days 51 to 150 of gestation using transabdominal real-time ultrasonography. There was a significant association (P < 0.005) between the number of lambs born and the number of fetuses observed using transabdominal real-time ultrasonography after Day 25 of gestation. Accurate differentiation of fetal numbers by transabdominal scanning was 100.0% for ewes carrying one lamb and 97.3% for ewes carrying two lambs at Days 51 to 75 of gestation. Fetal attrition was documented in one ewe at Day 49 of gestation. Hydrops allantois was diagnosed in another ewe at 110 d of gestation. A total of 37 lambs were born to 23 ewes in the project flock. No congenital abnormalities were noted in any of the lambs. Transabdominal real-time ultrasonography is a safe, rapid, accurate and practical method for assessing pregnancy status, fetal number and fetal viability in sheep.  相似文献   

3.
Ultrasonography (US) provides detailed visualization of the fetus in early pregnancy in cows, thus allowing for fetal sex determination. The objective of this prospective observational study was to determine the feasibility and accuracy of a single US examination to diagnose fetal sex in dairy cattle under routine reproductive management conditions. For this purpose, 953 Holstein cows at 7-16 weeks of gestation were examined. Gender assignment was performed in 822 cows, while the genitalia could not be clearly visualized in 131 (13.7%) of the fetuses. After calving, it was verified that 99.3% of the diagnoses were accurate. Fetal sex was correctly determined by US in 99.5% of male fetuses and 98.8% of female fetuses. Fetal sex determination was less accurate when conducted before d 55 of gestation. Likewise, it was verified that fetal sex, cow age and ultrasonographic diagnosis section did not have a significant influence (P>0.05) on diagnostic accuracy. With respect to the plane used for diagnosis, the sagittal view was poorly used for early pregnancy diagnosis, whereas the longitudinal and cross-sectional planes were used most frequently. These results demonstrate that US can be routinely applied under farm conditions to accurately determine the fetal sex in cattle between days 51 and 111 of gestation without apparent influence of cow age, US scanning plane or fetal sex. Conversely, days of gestation affected the accuracy and feasibility of US gender determination, showing poorer results when the diagnosis was made before day 55 of gestation.  相似文献   

4.
Mouse prostatic hyperplasia can be induced experimentally by the direct implantation of fetal urogenital sinus (UGS) or its mesenchyme (UGM) tissue in situ. This study characterized the time course, the requirement of sex steroids, and the optimal ages of donor and host tissues necessary to induce the maximal overgrowth of the adult mouse prostate gland in this model system. To test the potential uses of these fetal inductors as general growth-promoting substances for other adult organs, we have also tested directly the activity of fetal UGS in several non-UGS-derived adult organs. These results were compared with the growth-promoting effect achieved by fetal UGM in order to gain further insight into the relative contribution of UGS/UGM in the overall growth responses. Peak DNA synthesis in the implanted prostate occurred at three time periods-Days 4, 7-16, and 35. At Day 4, DNA synthesis may have reflected tissue repair following surgical trauma, but the DNA synthesis on Days 7-16 and 35 is attributable to growth of the chimeric (enlarged) prostate gland. Initiation and maintenance of hyperplasia required testicular androgens. Exogenous testosterone propionate (175 micrograms/day) did not induce additional prostatic overgrowth in intact, sexually mature hosts, but promoted additional overgrowth in immature and pubertal hosts. Exogenous estrogen (17 beta-estradiol dipropionate, 20 micrograms/day) inhibited fetal UGS-induced prostatic overgrowth by inhibiting the hypothalamic-pituitary-testicular axis. UGS derived from fetuses of Days 14, 16, or 18 of gestation had similar growth-inductive capability in intact adult hosts, but this capability was restricted soon after birth.(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   

5.
Prenatal diagnosis based on rare fetal cells in maternal blood is currently not a feasible option. An effort was made to improve cell yields by targeting trophoblast cells. After sorting, the HLA-G-positive cell fraction was analyzed directly or after culture. In situ hybridization technology was applied to prove fetal cell source in samples from women carrying a male fetus and to predict gender in samples without previous knowledge of fetal sex. In vitro culture led to a significant increase in fetal cells and accurate gender prediction in 93% of these samples. This approach might be useful for non-invasive prenatal diagnosis.  相似文献   

6.
A case of triploidy identified in second trimester fetal diagnosis is presented. Cytogenetic study was undertaken in chorionic willi obtained by transabdominal placentocentesis. The diagnosis was confirmed by cytogenetic analysis of cultured amniotic fluid cells. The observation was revealed within a programme of combined ultrasound and cytogenetic prenatal monitoring, in association with maternal age. The fetus aborted at 23 weeks of pregnancy was abnormal, including congenital malformations and hypoplasia of internal organs and placenta.  相似文献   

7.
Background:Noninvasive fetal sex determination by analyzing Y chromosome-specific sequences is very useful in the management of cases related to sex-linked genetic diseases. The aim of this study was to establish a non-invasive fetal sex determination test using Real-Time PCR and specific probes.Methods:The study was a prospective observational cohort study conducted from August 2018 to September 2019. Venous blood samples were collected from 25 Iranian pregnant women at weeks 7 to 25 of gestation. Cell-free DNA (cfDNA) was isolated from the plasma of samples and fetal sex was determined by SRY gene analysis using the Real-Time PCR technique. In the absence of SRY detection, the presence of fetal DNA was investigated using cfDNA treated with BstUI enzyme and PCR for the epigenetic marker RASSF1A.Results:Of the total samples analyzed, 48% were male and 52% female. The RASSF1A assay performed on SRY negative cases also confirmed the presence of cell-free fetal DNA. Genotype results were in full agreement with neonate gender, and the accuracy of noninvasive fetal sex determination was 100%.Conclusion:Fetal sex determination using the strategy applied in this study is noninvasive and highly accurate and can be exploited in the management of sex-linked genetic diseases.Key Words: Cell-free fetal DNA, Fetal sex determination, Noninvasive prenatal diagnosis, Sex-linked genetic diseases, SRY  相似文献   

8.
We ultrasonographically evaluated the prenatal development in cats, from Day 30 to the end of pregnancy, subjecting a group of pregnant cats (n = 8) to daily ultrasonographic examinations. The ultrasonographic images allowed us to measure the diameter of the fetal abdomen, the biparietal diameter of the fetal skull and the diameter of the fetal stomach. A correlation between these measurements and gestational age was found with a linear, parabolic and exponential regression analysis. From Days 38 to 43 after breeding we also performed fetal gender determination by evaluating the external genitalia. All queens successfully carried their pregnancies to term. This study compiled useful new data in order to clinically monitor the normal course of pregnancy in cats and to determine gestational age.  相似文献   

9.
利用孕妇血浆DNA检测胎儿性别的研究   总被引:6,自引:0,他引:6  
本文探讨应用孕妇血浆中游离DNA进行无创性产前性别诊断的可行性。用柱分离法提取73例孕妇血浆中DNA,用巢式PCR技术检测其胎儿SRY基因。 结果73位孕妇血浆DNA含量为0.0062~0.3399μg/μL。巢式PCR检测胎儿SRY基因的灵敏度为97.37%(37/38),假阴性率2.86%(1/35),特异度85.71%(30/35),假阳性率13.16%(5/38),总符合率91.78%(67/73)。采用孕妇血浆胎儿DNA和巢式PCR技术可以快速简便的进行无创性产前性别诊断,诊断结果的准确率为91.8%,对性连锁遗传病的预防具有重要意义。 Abstract:To investigate the feasibility and possibility of application of fetal DNA from maternal plasma for noninvasive prenatal diagnosis of fetal sex,plasma DNAs in blood samples of 73 pregnant women at the gestational period of 26 to 41 weeks were extracted by column separation and nested polymerase chain reaction were employed to amplify the SRY gene.A comparison was made between the amplification results and the real sex of the fetus after their delivery.The concordance rate of SRY gene amplification results of plasma free DNA with real fetal sex was 91.78% (67/73),the sensitivity rate was 97.37% (37/38),and the specific rate was 85.71% (30/35).The cell-free fetal DNA in maternal blood can be one of the valuable material sources for noninvasive prenatal diagnosis and the method of nested PCR could be useful for fetal sex determination.The specific rate of the test was 91.78%.It is of significance to prevent sex-linked inheritant diseases.  相似文献   

10.
Great advances in ultrasound instrumentation have enabled the physician to delineate subtle intrauterine changes. Not only can specific measurements of the fetal body be obtained but tissue textures within fetal organs can be appreciated. The perinatologist is constantly searching for ways to learn more about the fetus, and ultrasound has clearly become a major implement in this search. The following discussion will focus on information made available by ultrasound for aid in the modern management of hypertension, one of the most challenging conditions complicating pregnancy.  相似文献   

11.
We present prenatal diagnosis of mucopolysaccharidosis type II (MPS II) (Hunter syndrome) and demonstrate marked mucopolysaccharide deposition in multiple vital organs in a 22-gestational-week affected fetus. Level II ultrasound showed cardiomegaly and hepatomegaly. Histological examinations of the fetal vital organs manifested marked mucopolysaccharide deposition. We suggest that any therapeutic approach and counseling for prenatally diagnosed MPS II should consider the early signs of in utero marked mucopolysaccharide storage.  相似文献   

12.
Ultrasound imaging has been used to elucidate certain aspects of the reproductive biology of wild or endangered species. However, to our knowledge, this tool has not been used for reproductive monitoring of the collared peccary (Tayassu tajacu). In this study, real-time ultrasonography was used in 16 collared peccary females to diagnose early pregnancy status and predict gestational age. Based on the detection of an embryo, the earliest pregnancy diagnosis was made on Day 18 after mating, with the mean time needed for diagnosis being 22 days. Overall accuracies on Days 22, 26 and 28 were 56, 93, and 100%, respectively. On Days 26 and 28, all pregnancy and non-pregnancy diagnoses, respectively, were correct. The fetal measurements that best correlated with gestational age were crown-rump-length (CRL) and the length and diameter of the thorax. CRL was considered the most practical measurement because, contrary to thoracic fetometry, it could be determined when the embryo was first detected. Our findings revealed real-time ultrasound scanning to be a very accurate method for early pregnancy diagnosis and prediction of gestational age in the collared peccary.  相似文献   

13.
Zambelli D  Prati F 《Theriogenology》2006,66(1):135-144
In the present paper, we describe the clinical utility of ultrasonography for diagnosing and evaluating pregnancy in domestic cats. Ultrasonography is a non-invasive technique that permits an accurate diagnosis of pregnancy and allows serial evaluation of the developing embryo/fetus and the extrafetal structures. The first ultrasonographic indication of pregnancy is a gestational chamber seen on day 10 after mating as a small circular anechoic structure. From day 30, it is possible to recognize different fetal organs, and between 38 and 43 days, the gender of the fetus can be determined. Measurements obtained during the second half of gestation can be used to determine fetal age and calculations can then be made that may more accurately predict the time of parturition. Further studies are needed in the queen to determine the applicability of the echo-Doppler technique used routinely in human obstetric medicine. This type of ultrasonography could potentially provide useful information about fetal health and the maturity of the placenta.  相似文献   

14.
The aim of this study was to establish baseline ultrasound data concerning the mule conceptus during gestation. Ten multiparous Trotter mares were artificially inseminated with chilled semen from an Amiatino jack donkey. Daily transrectal ultrasonography was carried out from the day of ovulation until Day 50 of gestation to determine the following: first detection of the embryonic vesicle (EV), mobility phase, EV diameter, day of EV fixation, changes in EV shape, date of yolk sac regression and embryo crown-rump length. Monthly ultrasonic assessments from Day 50 of gestation to term were carried out. These assessments included an evaluation of fetal well-being and the growth of the mule conceptus, which were monitored using the following variables: cardiac activity, fetal activity and presentation, fetal fluid echogenicity, combined thickness of the utero-placenta unit and fetal orbital and aortic diameter. Mule EV first detection was observed earlier (37% at Day 8) than that observed in the equine pregnancy. EV diameter at first detection was 4.6 ± 1.1 mm. At Day 10, 75% of EVs were detected. EV fixation occurred on Day 17.1 ± 1.1, with a mean EV diameter of 2.5 ± 0.2 cm. EV growth rate was 4.04 mm/day from Days 11 to 16, 0.4 mm/day from Days 16 to 28 and 1.78 mm/day from Days 28 to 45 of pregnancy. The embryo proper was first detected on Day 19.9 ± 1.9 (average length 2.4 ± 1.4 mm), and the embryonic heartbeat was first detected on Day 24 ± 2.4. The fetal carotid pulse was observed at six months of gestation and provided a good means by which to estimate fetal cardiac activity in advanced gestation. The fetal heart rate was recorded from Month 2 of gestation to term. The mean ± SD of the combined uteroplacental thickness was assessed at the cervical-placental junction and at the ventral abdomen in mares between Months 2 and 5 until term, respectively. An abnormal fetal-placental unit and fetal inactivity was observed in association with abortion. Mule-conceptus biometric measurements correlated significantly with the gestational age, and these data were used to predict an unusually large mule fetus, which might result in dystocia. In conclusion, we can assume that early diagnosis of pregnancy failure and assessment of fetal biophysical profile and growth charts could improve the chances of gestation completion in mule-pregnant mares. The early detection of mares at risk for an abnormal pregnancy or delivery may increase the success of prompt treatments, therefore preventing costly emergency procedures and allowing proper obstetrical and neonatal assistance.  相似文献   

15.
Accuracy of transrectal ultrasonic diagnosis of fetal gender by identifying and locating the genital tubercle was assessed in 85 horses and 102 dairy heifers and cows. Examinations were made once (horses and cattle) under farm conditions (cattle) on approximately Days 50 to 100. Definite diagnosis was made by removal of fetuses (horses) or after calving or abortion (cattle). In both species and both parities, accuracy was 100% (109 109 totaled over both species) when the certainty level recorded at the time of examination was 95 or 99%. At the lower levels of certainty (65 to 80%, 85 to 90%), the accuracy was 89% (57 64 totaled over both species). A diagnosis was not obtainable in 10 horses (12%) and 5 cattle (5%); this was especially due to inadequate viewing of the fetus when the fetus was beyond Day 64. The time from completion of evacuation of the rectum to diagnosis of gender averaged 1 minute 17 seconds in horses (range, 15 seconds to 3 minutes 55 seconds). The corresponding figure in cattle was 1 minute 53 seconds (range, 16 seconds to 8 minutes 30 seconds).  相似文献   

16.
吴云  胡涛  杨玲  查文  曹荔 《生物磁学》2013,(34):6719-6722
目的:探讨超声检查发现胎儿先天发育异常的规律及诊断价值。方法:随机选择480例经产后及引产后证实的单胎妊娠的畸形胎儿,回顾性分析产前的超声检查资料,孕妇平均年龄27.6岁,平均孕周27.1周。超声诊断畸形儿统计标准:参照《中国出生缺陷监测报告卡》的监测类型和《临床技术操作规范(超声医学分册)》的检测畸形类型确定。结果:459例为经超声检出的胎儿先天畸形,21例为超声漏诊,根据胎儿出生后情况反馈为畸形。459例畸形胎儿,孕周在12-40周,其中24.4%(112/459)的病例是在18-24孕周之间检出,56.9%(261/459)的病例是在12—28孕周之间检出,其中24周检出病例数最多(42/459)。35.7%(164/459)的胎儿畸形是在孕28-36周期间检出。结论:超声对胎儿畸形的诊断符合率为95.62%(459/480)。妊娠28周前超声能检出大多数可检的胎儿畸形。超声在胎儿产前诊断上具有极高的诊断价值,诊断率高,无损伤性,操作简便,重复性强。  相似文献   

17.
The aims of the present study were to evaluate and compare the accuracy of transrectal ultrasonography and pregnancy-associated glycoprotein radioimmunoassay (PAG-RIA) test for diagnosis of pregnancy in buffaloes. Two hundred and seventy-five buffalo cows and heifers were examined once for pregnancy diagnosis by transrectal ultrasonography using a 5 MHz linear-array transducer between Days 19 and 55 after mating. After ultrasound scanning, a blood sample was withdrawn from jugular vein of each animal for measuring pregnancy-associated glycoprotein using a heterologous double-antibody RIA. Based on palpation of the uterus per rectum at Days 75-90, 87 animals were designated pregnant and 188 as non-pregnant. The sensitivity of transrectal ultrasonography at Days 19-24 was 44.4%, reaching 100% from Day 31 after mating. The specificity of transrectal ultrasonography ranged between 92.5 and 100% from Days 19 to 55 after mating. The sensitivity of PAG-RIA test was 11.1% at Days 19-24 and reached 100% from Day 31 after mating. The specificity of PAG-RIA test ranged from 90 to 100% from Days 19 to 55 after mating. There were no significant differences between the sensitivity and specificity of the two tests in all examined periods. In conclusion, transrectal ultrasonography and PAG-RIA test are highly accurate tests for detecting pregnant buffaloes from Day 31 after mating onwards.  相似文献   

18.
Fetal sex can be determined by the polymerase chain reaction (PCR) using cells from fetal fluid collected by transvaginal ultrasound-guided amniocentesis. A total of 35 aspirates from 30 cows, 15 Holsteins and 15 Japanese Blacks at 59 to 250 d of pregnancy were used. Five cows were aspirated twice at a 10-d interval. A 5.0 MHz convex array transducer connected to a scanner was inserted into the vagina under caudal epidural anesthesia. The transducer was equipped with a 65-cm long, 21-g needle within the probe carrier. A bovine male-specific primer and a bovine gender-neutral primer were used. Fetal fluid was obtained from all except 2 cows in early pregnancy. Five animals aborted within 1 wk following aspiration. A total of 33 samples, 29 of amniotic fluid and 4 of allantoic fluid, was subjected to PCR analysis. Fetal gender was verified in 31 33 samples (18 females and 13 males). Gender was also determined by gross examination of external genitalia of offspring after calving or abortion. Fetal gender was correctly identified by PCR analysis of aspirated fetal fluid in 16 16 females and in 13 15 males. Transvaginal ultrasound-guided amniocentesis followed by PCR analysis of aspirated cell DNA can be used accurately to determine fetal sex in cows at 70 to 100 d of gestation. The procedure requires considerable skill and is not without some risk to fetal viability.  相似文献   

19.
Congenital adrenal hyperplasia is a group of inherited disorders caused by an enzyme deficiency in steroid biosynthesis. The most common form of congenital adrenal hyperplasia is 21-hydroxylase deficiency, which in its severe form can cause genital ambiguity in females. Steroid 21-hydroxylase deficiency can be diagnosed in utero through molecular genetic analysis of fetal DNA. Prenatal treatment successfully reduces genital ambiguity, and the subsequent problems of sex misassignment and gender confusion. Data from current studies show that prenatal diagnosis and treatment are safe for the mother and the fetus. The evidence also suggests that it is safe over the long term, but all subjects exposed to dexamethasone treatment during embryonic and fetal life should have their physical, cognitive and emotional developments recorded.  相似文献   

20.
目的:探讨产前B超对胎儿完全性大动脉转位的临床诊断价值。方法:回顾性分析2012年2月至2015年11月我院收治的4例胎儿完全性大动脉转位的B超特征,并对比病理结果。结果:4例完全性大动脉转位胎儿中,1例室间隔缺损,3例四腔心切面正常。左右两室流出道切面情况:4例胎儿大动脉与心室连接关系存在异常,2例胎儿室间隔膜部存在缺损症状。三血管气管切面情况:4例胎儿均仅可见2条血管。结论:对左右两心室流出道切面及三血管气管切面进行观察可得,胎儿完全性大动脉转位具有较为明显的B超特征,产前对胎儿完全性大动脉转位进行B超诊断具有较好的临床价值,建议在医疗单位推广应用。  相似文献   

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