oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Search Results: 1 - 10 of 139 matches for " oocytes "
All listed articles are free for downloading (OA Articles)
Page 1 /139
Display every page Item
Effect of vitrification procedure on chromosomal status of embryos achieved from vitrified and fresh oocytes  [PDF]
Javier I García, Luis Noriega-Portella, Luis Noriega-Hoces
Health (Health) , 2011, DOI: 10.4236/health.2011.37077
Abstract: Background: In order to assess the chromosomal status in embryos obtained from vitrified and fresh donated oocytes, preimplantational genetic diagnostic (PGD) was performed after biopsy of one blastomere at day 3. METHODS: A total of 249 oocytes were obtained from 23 oocyte donors, 80 oocytes were used in the vitrified group and 151 oocytes were used in the fresh group. Nine chromosomes (13, 15, 16, 17, 18, 21, 22, X and Y) were investigated by fluorescence in situ hybridization (FISH) analysis in 56 and 121 embryos from vitrified and fresh group respectively. Fertilization, cleavage rate, embryo quality and chromosomal abnormality rate were compared between groups evaluated. Results: Vitrified oocytes showed a survival rate of 97.5%. There was no significant difference in the fertilization rate (82.7% and 91.4%), Day 2 cleavage rate (90.3% and 87.7%) or blastocyst formation rate (31.1% and 44.6%) for the vitrified and fresh groups respectively. Chromosomal abnormality rate (66.1% versus 71.9%), percentage of abnormal blastocysts (61.1% versus 64.8%) and percentage of abnormalities for each analyzed chromosome were similar for the vitrified group compared with the control group. Conclusions: The rates of chromosomal abnormalities in embryos from vitrified oocytes are similar to those published previously; and comparable to those observed in embryos from fresh oocytes. These results confirm that the developmental competence and chromosomal status of embryos obtained from vitrified oocytes is not affected by the vitrification procedure, and they preserve the potential to be fertilized and to develop in to blastocyst stage similar to embryos from fresh oocytes.
High pregnancy and implantation rates can be obtained with preincubation of oocytes before insemination in IVF and ICSI procedures  [PDF]
Javier García-Ferreyra, Pedro Valdivieso, Milton Zambrano, Jorge Carpio
Health (Health) , 2012, DOI: 10.4236/health.2012.49104
Abstract: Purpose: Evaluate the effect of preincubation of oocytes prior to IVF or ICSI cycles with embryo transfer at blastocyst stage. Methods: Retrospective non randomized study based on secondary analysis of data. Setting: Laboratory of Assisted Reproduction at the Alcivar Hospital. Patients: One hundred-eighteen cycles of IVF and ICSI were analyzed in the present study. The evaluated groups were formed for those patients whose oocytes, after retrieval, were inseminated at 1-3 h (Group I) or 4-6 h (Group II). Results: There was no difference in fertilization rate (83.6% and 78.1%), Day 3 cleavage rate (95.1% and 97.1%), and blastocyst formation (31.1% and 39.1%) for groups I and II respectively. Clinical pregnancy rates (PR: 53.0% vs 22.9%) and implantation rates (IR: 38.1% vs 13.0%) were significantly higher in group II versus group I, respectively (P < 0.05). Conclusions: Preincubation of oocytes before insemination is a factor which raises the PR and IR after the blastocyst transfer.
Cohesin in Oocytes—Tough Enough for Mammalian Meiosis?
Ekaterina Revenkova,Caroline Adelfalk,Rolf Jessberger
Genes , 2010, DOI: 10.3390/genes1030495
Abstract: Sister chromatid cohesion is essential for cell division. During meiosis, it is also required for proper synapsis of pairs of sister chromatids and for chiasma formation and maintenance. Since mammalian oocytes remain arrested in late prophase for a very long period—up to five decades in humans—the preservation of cohesion throughout this period is a formidable challenge. Mouse models with cohesin deficiencies and aging wild-type mice showed that this challenge is not fully met: cohesion weakens and deteriorates with increasing age. These recent findings have highly significant implications for our comprehension of the genesis of aneuploidies.
Características Morfológicas de Ovarios y Ovocitos de Nutrias (Myocastor coypus) en Condiciones de Criadero
Larocca,Clara; Fila,Danilo; Filipiak,Yael; Pérez,William;
International Journal of Morphology , 2011, DOI: 10.4067/S0717-95022011000200020
Abstract: the aim of this work was to study the morphological characteristics of ovaries and oocytes of the otter (myocastor coypus, coypu) in different seasons and stages of the estrous cycle. the otter (mc) is a rodent native to south america and is widely used in the fur industry. twenty females with a mean weight of 4996.2 g were sacrificed, vaginal swabs or colpocytology were collected and the time of the estrous cycle was determined. eleven were slaughtered in winter, of which 7 were in anestrus, 1 in proestrus, and 3 in diestrus; of the 9 slaughtered in summer, 1 was in anestrus, 1 in proestrus and 7 in diestrus. each ovary was transported to the laboratory in a solution of sterile isotonic sodium chloride at 37° c. the ovaries were weighed and measured and crumbled into petry dishes with two no.28 needles, under a stereoscopic microscope. oocytes were identified, washed in phosphate buffered saline solution (pbs) and were characterized as a, b and c. the results of mean and standard deviation of the weights of the ovaries were: 0.304 g (0.062), length 9.05 mm (0.19) and 5.05 mm wide (0.69). we performed the analysis of variance for the condition of oocytes and found no statistically significant differences associated with the station or estrus status on the status of the oocytes (p <0.05). regarding the number of corpora lutea, fisher′s test was used, with significant differences between stages of estrous cycle (diestrus vs. anestrus) with f=20.57 (p = 0.0001) between seasons (summer vs. winter) with f = 72.21 (p = 0.0000) and interaction between the stages and stations with an f = 10.29 (p = 0.0018).
Structural and Ultrastructural Aspects of Folliculogenesis in Didelphis albiventris, the South-American Opossum
Cesario,Maria Dalva; Matheus,Selma M. Michelin;
International Journal of Morphology , 2008, DOI: 10.4067/S0717-95022008000100019
Abstract: the ovarian histology, the structural and the ultrastructural characteristics of the folliculogenesis in didelphis albiventris were described in detail. recent studies suggest that methatherian mammals have unusual reproductive cycle but there are few informations regarding the marsupials reproductive life. despite of the opossum folliculogenesis pattern resembles methatherian and eutherian pattern in many aspects, the analysis shows some peculiar features of the oocyte structure and ultrastructure that make available new data on the reproductive biology of marsupials.
ESTUDIO COMPARATIVO DE OVARIOS Y CUBIERTAS OVOCITARIAS EN PECES SILURIFORMES DE AGUAS CONTINENTALES DE CHILE
Huaquín,Laura G.; Veliz,Dina; Arratia,Gloria;
Gayana (Concepción) , 2002, DOI: 10.4067/S0717-65382002000200026
Abstract: reproductive biology including the mode, timing and duration of spawning can be inferred from the ovarian structure of fishes. this study describes and analyses ovarian and oocyte structure of two siluroid species, the one nematogenys inermis threatened with extinction, the other, trichomycterus areolatus, the most abundant and widespread in chilean continental waters. histological sections (6 mm) of ovaries fixed in bouins fluid were routinely stained with hematoxilin-eosin and some with trichromic (azan) and periodic acid schiff (pas). histologically the ovarian wall consisted of an external serosa, a median tunic and ovarian epithelia. the tunic reaches internally with leaflets of connective tissue comprising the ovaric strome. in mature ovaries of t. areolatus oocytes with several developmental stages were observed. this indicates asynchronous maturation with spawning taking place throughout the reproductive period. n inermis showed partial synchronisation indicating a single spawning activity in the reproductive cycle. in both species the immature oocytes are enveloped with the plasma membrane. mature ova show well developed envelopes, a radiata zone, folicular epithelium with basal membrane and an external theca, with specific differences shown by the ovocytic envelopes
Morphology and Histology of the Female Reproductive System of Abedus ovatus Stal (Belostomatidae: Hemiptera: Insecta)
Memórias do Instituto Oswaldo Cruz , 1997, DOI: 10.1590/S0074-02761997000100028
Abstract: in abedus ovatus stal, the female reproductive system consists of a pair of ovaries leading to oviduct and opens out by genital aperture. each ovary is composed of five telotrophic ovarioles, with four different regions, terminal filament, germarium, vitellarium and pedicel. germarium and vitellarium are the germ tubes in which the development of oocyte occurs. in the germarium, the differentiation of trophocytes into young oocytes was observed in three zones, zi, zii and ziii. further development of oocytes in the vitellarium could be divided into seven stages, sti stvii. the developed eggs are lodged in the pedicel
Vitrificación de ovocitos bovinos y su uso en el desarrollo partenogenético de embriones
Ruiz,J; Correa,JE; Martínez,M;
Archivos de medicina veterinaria , 2010, DOI: 10.4067/S0301-732X2010000100011
Abstract: the aim of this study was to evaluate vitrification effects on the viability of chemically activated oocytes in order to produce parthenogenetic bovine embryos. bovine oocytes retrieved from ovaries obtained in a slaughterhouse were matured in vitro for 20-22 hours and then assigned to the following groups: i (n=76): vitrified/thawed oocytes, ii (n=119): exposed oocytes to cryoprotectans without vitrification and iii (n=142): control oocytes. bovine oocytes were vitrified in microdrops on a precooled aluminum foil floating in liquid nitrogen, using an equilibrium solution with 4% ethylene glycol and a vitrification solution with 35% ethylene glycol, 5% polyvinyl-pyrrolidone and 0,4 m trehalose. the vitrified microdrops were stored in liquid nitrogen and were thawed after 1-3 days of storage. the oocytes of the 3 groups were parthenogenetically activated by 4-min exposure to 5 μm ca ionomycin at room temperature followed through 5 hours incubation in 6-dimethylaminopurine at 38.5 oc in a 5% co2 in humidified atmosphere. embryos were cultivated on msof medium during 8-9 days. the rates of oocytes survival were 55.1% and 93.7% to vitrified/thawed (i) and exposed (ii) oocytes respectively. the rates of cleavage were 55.3%, 72.3% and 74.6%; and development to blastocysts were 7.1%, 17.4% and 21.7% in groups i, ii and iii respectively. these results demonstrate that the oocyte vitrification technique has been set up in our laboratory and parthenogenetic bovine embryos can be produced from such as vitrified/thawed oocytes.
Fecundidade da manjuba Curimatella lepidura (CURIMATIDAE) na represa de Três Marias, rio S?o Francisco, MG
Andrade, D.R;Vidal Junior, M.V;Godinho, H.P;Tonini, W.C.T;Burket, D;
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2010, DOI: 10.1590/S0102-09352010000600016
Abstract: the sizes of vitellogenic oocytes and fecundity of 230 females of manjubas (curimatella lepidura) from the três marias reservoir, river s?o francisco, mg, was determined throughout three years of monthly captures. gravimetric method was used to determine the quantities of vitellogenic oocytes, which were separated from no vitellogenics by weight difference and using water flow. the average diameter of vitellogenic oocytes was 711±44μm. the mean absolute fecundity was 60994.9±27142.7 oocytes per female in stage 2c of maturation (mature). the average fecundity relative to body weight and ovarian weight was 1294.1±437.5 and 8293.8±1961.9 oocytes per gram, respectively. there was no significant difference (p<0.05) between fecundity during the three years of research. high correlation coefficients were found, and the linear and potential models were the most appropriate to express the absolute and relative fecundities, i.e., the higher the maturity degree, higher the fecundity
Vitrifica??o de ovócitos imaturos de bovinos utilizando etilenoglicol associado à trehalose e polivinilpirrolidona
Souza, M.R.;Costa, E.P.;Torres, C.A.A.;Guimar?es, J.D.;Fagundes, L.M.;
Arquivo Brasileiro de Medicina Veterinária e Zootecnia , 2003, DOI: 10.1590/S0102-09352003000500011
Abstract: this study aimed to evaluate the effects of vitrification procedure of immature bovine oocytes using ethylene glycol (eg) associated with trehalose and polivinylpyrrolidone on the percentage of recovered oocytes with normal morphology and nuclear maturation, fecundation and cleavage rates for in vitro cultivated embryos. ovary oocytes of slaughtered cows were randomly allotted to three treatments (t): ti - oocytes neither undenuded nor vitrified, tii - vitrified oocytes with cumulus oophorus, tiii - undenuded vitrified oocytes. the percentage of recovered oocytes and oocytes with normal morphology after vitrification was different for tii and tiii (92.2 and 72.6%, 79.0 and 63.3% for tii and tiii, respectively). all normal oocytes were cultivated at 38.5oc in atmosphere with 5% co2 for 24 hours. after culture, the oocytes were fecundated and the embryos were cultivated in vitro for seven days. the nuclear maturation, fecundation and cleavage rates for ti, tii and tiii were different (83.9, 70.0 and 44.0%, 17.5, 23.7 and 5.1%, 0.0, 0.0 and 0.0% for ti, tii and tiii, respectively). morulas and blastocysts were obtained only for ti (21.4%). these results indicate that the protocol used for vitrification procedure is not recommended for cryopreservation of immature bovine oocytes.
Page 1 /139
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.