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101.
Assessment of the viability and pregnancy potential of mouse embryos biopsied at different preimplantation stages of development 总被引:2,自引:1,他引:2
The developmental potential in vitro and in vivo of preimplantation mouse embryos biopsied at the 4-cell, 8-cell and morula stages were investigated. Biopsy had the least impact when performed at the 8-cell stage. There was no effect of biopsy on the development of 8-cells of blastocysts in vitro (95% compared with 99% of controls) or the implantation rate after transfers (82 versus 87%, P greater than 0.05); however, fewer embryos (52 versus 71%, P less than 0.05) resulted in viable fetuses. There was no effect of biopsy at the 8-cell stage on fetal weight on day 17. Blastocyst formation in vitro was significantly less for 4-cell biopsies compared with their controls (76 versus 90%, P less than 0.001) and biopsy also affected the implantation rate (44 versus 59%, P less than 0.01). Biopsy was most detrimental when performed on morulae, reducing the implantation rate from 65% for controls to 21% for biopsies (P less than 0.001). Fetal viability was also markedly affected with a reduction on day 17 from 42 to 26% accompanied by a significant reduction (24%, P = 0.02) of the mean fetal weight. Handling of embryos for biopsy at the morula stage, which involved removal of the zona pellucida, was a significant but not complete cause of the reduced implantation potential observed (sham-controls and intact-controls: 34 and 65%, P less than 0.001), while puncture of the zona during the biopsy of 4-cell and 8-cell embryos had no effect. Therefore, the 8-cell mouse embryo is the most suitable state for embryo biopsy. 相似文献
102.
一种更接近X线管焦点MTF的抽样函数 总被引:2,自引:0,他引:2
本文提出了一种线扩散函数,用以从理论上估算X线管的MTF。结果表明较脉冲函数更加实际,而且在空间频率较大的区域也较准确。 相似文献
103.
104.
Ultrasound-guided embryo transfer improves pregnancy rates and increases the frequency of easy transfers 总被引:7,自引:0,他引:7
Matorras R Urquijo E Mendoza R Corcóstegui B Expósito A Rodríguez-Escudero FJ 《Human reproduction (Oxford, England)》2002,17(7):1762-1766
BACKGROUND: Recent reports have suggested that ultrasound (US) guidance during embryo transfer might improve pregnancy rates. METHODS: A prospective randomized (computer-generated random table) trial was performed to compare embryo transfer under abdominal US guidance (n = 255 women) with clinical touch embryo transfer (n = 260). RESULTS: The clinical pregnancy rate was 26.3% (67/255) in the US-guided transfer group compared with 18.1% (47/260) in the clinical touch transfer group (P < 0.05). The implantation rate was 11.1% (100/903) in the US group compared with 7.5% (66/884) in the clinical touch group (P < 0.05). US-guided transfer was associated with a decrease in the difficulty of the transfers: 97% of transfers were easy in the US-guided group compared with 81% in the clinical touch group (P < 0.05). CONCLUSIONS: US-guided embryo transfer increased pregnancy and implantation rates in IVF cycles, as well as the frequency of easy transfers. It is suggested that the decrease in cervical and uterine trauma can play a role in the increase in pregnancy rates associated with US-guided transfer. It is recommended that embryo transfer should be performed under US guidance. 相似文献
105.
106.
Smith KR 《International journal of medical sciences》2004,1(2):76-91
The theoretical possibility of applying gene transfer methodologies to the human germline is explored. Transgenic methods for genetically manipulating embryos may in principle be applied to humans. In particular, microinjection of retroviral vector appears to hold the greatest promise, with transgenic primates already obtained from this approach. Sperm-mediated gene transfer offers potentially the easiest route to the human germline, however the requisite methodology is presently underdeveloped. Nuclear transfer (cloning) offers an alternative approach to germline genetic modification, however there are major health concerns associated with current nuclear transfer methods. It is concluded that human germline gene therapy remains for all practical purposes a future possibility that must await significant and important advances in gene transfer technology. 相似文献
107.
Lettuce anaphylaxis: identification of a lipid transfer protein as the major allergen 总被引:2,自引:0,他引:2
San Miguel-Moncín M Krail M Scheurer S Enrique E Alonso R Conti A Cisteró-Bahíma A Vieths S 《Allergy》2003,58(6):511-517
BACKGROUND: Allergy to plant-derived foods is associated with birch pollinosis in central and northern Europe. Symptoms elicited are usually limited to the oropharyngeal system. By contrast, in the Mediterranean area, allergy to the same foods manifests more frequently with systemic reactions caused by nonspecific lipid transfer proteins (nsLTP), independently of an associated pollinosis. OBJECTIVE: We sought to investigate the pattern of immunoglobulin E (IgE) binding protein bands implicated in lettuce allergy, in particular the presence of an nsLTP. METHODS: Consecutive lettuce allergic patients were selected. Determination of serum-specific IgE, immunoblot, and inhibition experiments were performed in order to study the pattern of IgE binding proteins and the potential cross-reactivity to pollens. Inhibition studies with recombinant allergens were conducted to identify the lettuce allergens. The major allergen was subjected to N-terminal amino acid sequencing. RESULTS: Fourteen patients were diagnosed as being allergic to lettuce. All were sensitized to Platanus pollen. Ten of them showed specific IgE to a lettuce protein of 9-kDa. The IgE binding to this protein was completely inhibited by the cherry-LTP and peach extract. The N-terminal sequence of the 9-kDa protein showed a high degree of amino acid sequence identity to other nsLTPs. A clear partial cross-reactivity was observed between lettuce-LTP and Platanus-pollen extract. CONCLUSIONS: An LTP has been demonstrated to be a major allergen in patients suffering from lettuce allergy. 相似文献
108.
Baril L Briles DE Crozier P King JD Hollingshead SK Murphy TF McCormick JB 《Clinical and experimental immunology》2004,135(3):474-477
PspA and PsaA are Streptococcus pneumoniae surface proteins and potential pneumococcal vaccine antigens. The aim of this study was to characterize the transplacental transfer of antibodies to PspA and to PsaA. Paired mother and cord blood sera were obtained at delivery from 28 women. Concentrations of antibodies against PspA, PsaA, tetanus toxoid (vaccine-induced antibodies) and P6-outer membrane protein (OMP) of nontypeable Haemophilus influenzae were determined by ELISA. Antibodies to PspA of the IgG, IgG1 and IgG2 antibodies were also determined. The geometric mean percentage (GM%) of the paired infant:mother antibody were calculated. Results: The GM% of the infant:mother antibody concentrations against PspA, PsaA and P6-OMP antibodies were 64.7% (3.3 micro g/ml in infants vs. 5.1 micro g/ml in mothers), 50.4% (6.8 micro g/ml vs. 13.5 micro g/ml) and 66.7% (5.6 micro g/ml vs. 8.4 micro g/ml), respectively; the GM% of antibodies against tetanus toxoid was 104.5% (4.6 micro g/ml vs. 4.4 micro g/ml). Transplacental transfer of IgG1 was more efficient than that of IgG2 (approximately 120%vs. 65%). A transplacental transfer of antibodies to PspA and to PsaA exist. Moreover, these data suggest an active placental transfer of IgG1 antibodies to PspA since the concentration of these antibodies were consistently higher in cord sera than in the mother's sera. 相似文献
109.
Puerta-Fonollá J Vázquez-Osorio T Ruiz-Cabello J Murillo-González J Peña-Melián A 《Clinical anatomy (New York, N.Y.)》2004,17(5):429-435
A study was carried out on the application of magnetic resonance microscopy (MRM) in teaching prenatal human development. Human embryos measuring 8 mm, 15 mm, 18.5 mm, and 22 mm were fixed in a 4% paraformaldehyde solution and sections obtained with magnetic resonance imaging (MRI) were compared to those prepared for light microscopy (LM), using the same embryos. The MRM and LM slices were of a similar quality. In the MRM sections, embryonic organs and systems were clearly visible, particularly the peripheral and central nervous systems, and the cardiovascular and digestive systems. The digitalization and clarity of the MRM images make them an ideal teaching aid that is suitable for students during the first years of a health-science degree, particularly medicine. As well as providing students with their first experience of MRM, these images allow students to access, at any time, all embryos used, to assess changes in the positions of different organs throughout their stages of development, and to acquire spatial vision, an absolute requirement in the study of human anatomy. We recommend that this technique be incorporated into the wealth of standard embryonic teaching methods already in use. 相似文献
110.
José M. Icardo 《Anatomy and embryology》1989,179(5):443-448
Summary This paper presents a scanning electron microscope study of the morphologic changes undergone by the endocardium during development of the atrioventricular (A-V) endocardial cushions. Prior to cell seeding into the cushions, endocardial cells show a regular, uniform morphology, many of them appearing to be oriented in the direction of the blood flow. Concomitant with the appearance of cells in the A-V cushions, endocardial cells lose their elongated appearance, become more flattened and adopt a variable morphology. Endocardial cells at this stage develop filopodia and lamellipodia, overlap each other and show a variable number of microvilli and different degrees of flattening. After completion of endocardial migration, the endocardial cells that remain in the plane of the endocardium become extremely flattened, the degree of overlapping decreases and the cells adopt a polygonal morphology. These changes in endocardial cell morphology appear to be related to endocardial cell activity. It is suggested that the whole endocardial cushion, not just the cells that migrate into the cushions, is involved in cushion development. The activity of the endocardial cells may be related to the maintenance of the integrity of the endocardium. 相似文献