Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Viable, intact rabbit sperm, prepared, processed, and flow cytometrically sorted, were used in this study to determine the influence of flow sorting on fertilization and embryo development. In experiment I, flow-sorted or control (unstained and unsorted) sperm were surgically inseminated into the uterine horn of hormonally primed does (10 to 12 does per time point). At 42 hr postsurgical insemination, flushed embryos were assessed for development. Fetal development was determined at day 7, day 14, and day 21 post-surgical insemination. Embryos resulting from does surgically inseminated with control sperm at 42 hr post-insemination were observed to be at the early morula stage of development (> 16 cell), whereas embryos from does inseminated with flow sorted sperm were at the 8- to 16-cell stage. No difference was observed between treatments at day 7, 14, or 21, however, there was a significant decrease in fetus number per doe inseminated with flow-sorted sperm over time. In experiment II, mature oocytes were flushed from the oviducts of superovulated does and coincubated in vitro (IVF) with flow-sorted or control rabbit sperm. Oocytes observed at 6 hr post-coincubation exhibited swollen sperm heads in the cytoplasm, demonstrating that fertilization had occurred (2 PN + T). There was a higher percentage of fertilized oocytes by 8 hr post-coincubation for both control (31%) and flow-sorted sperm (31%) when used for IVF. By 10 and 12 hr post-coincubation, little difference was observed in the number of fertilized oocytes between sperm treatments (52% and 66% for control vs. 57 and 54% for flow-sorted, respectively). These studies demonstrate that flow-sorted sperm are capable of fertilizing mature oocytes under in vitro conditions. In addition they show that flow sorting may not negatively influence fertilization events, but likely interferes during early embryonic and fetal development.
Mol Reprod Dev 1996 Feb
PMID:Flow cytometric sorting of sperm: influence on fertilization and embryo/fetal development in the rabbit. 882 25

Monoclonal antibodies and immunofluorescence microscopy, including laser confocal microscopy, were used in this study to point out the production of fibronectin, tenascin-c, and laminin in the cumulus-corona (CC) cells surrounding mature human oocytes from IVF-ET protocols in view of their presumptive importance in the coordination of the processes leading to fertilization and early embryo cleavage, including the final maturation of the ovum, the sperm-egg interaction, and the "complex biochemical dialogue" between the gamete and the oviduct through the tubal luminal environment. One hundred fifty mature oocyte-CC complexes were obtained from IVF-ET protocols and fixed in 4.0% buffered paraformaldehyde. Specimens were incubated with a panel of primary monoclonal antibodies (mabs) recognizing different epitopes of fibronectin, tenascin-c, and laminin and then with fluorescein isothiocyanate-conjugated goat anti-mouse IgG. Observations were made by a scanning confocal microscope (Sarastro 2000) and a photomicroscope (Polyvar, Reichert-Jung) equipped with epifluorescence optics. The immunohistochemical data demonstrated that human CC cells are capable of producing fibronectin and tenascin-c but that their production is not homogeneous in the CC population. In fact, fibronectin immunoreactivity was shown mostly by inner CC cells (mainly corona cells), whereas tenascin was produced by some cells scattered in the entire cumulus mass. Moreover, fibronectin and tenascin-c immunoreactive material was observed in the intracytoplasmic areas, at the plasma membrane level as well as in the extracellular matrix. On the contrary, laminin immunofluorescent material was found around plasma membranes of almost all CC cells, but a clear intracytoplasmic reaction was never observed. This leads us to assume that laminin in the extracellular matrix remains entrapped once produced by granulosa follicular cells and that in the postovulatory period no active secretion occurs in CC cells. Even though the functional role of these extracellular matrix proteins remains still unclear, it is reasonable to suggest that they are necessary in various steps of the reproductive process, i.e., from the pick-up of the oocyte, its transport through the oviduct, and fertilization, up until the early cleavage of the embryo. Finally, functional differences between "corona radiata" and "cumulus" cells during the oocyte denudation may be accounted for particular distribution of these adhesive proteins.
Mol Reprod Dev 1996 Mar
PMID:Heterogeneous distribution of fibronectin, tenascin-C, and laminin immunoreactive material in the cumulus-corona cells surrounding mature human oocytes from IVF-ET protocols--evidence that they are composed of different subpopulations: an immunohistochemical study using scanning confocal laser and fluorescence microscopy. 886 53

Parental age is the most important aetiological factor in trisomy formation in humans. Cytogenetic studies on germ cells reviewed here imply that (i) 2-4% sperm are aneuploid and 8.6% oocytes from IVF are hyperploid (ii) a paternal age effect may exist, and (iii) oocytes of aged women contain precociously separated chromatids in metaphase II. Trisomy data suggest that most aneuploidy is generated during meiosis I of oogenesis and is maternal age-dependent. Trisomy 18 is unique, originating mostly from maternal meiosis II errors. The extra gonosome in 47, XXY derives mostly from a paternal meiosis I error. Trisomy of individual chromosomes may remain low, linearly rise, or exponentially increase with advanced maternal age. Maternal age related trisomies involve achiasmatic and normochiasmate chromosomes, and chromosomes with disturbed recombination and distally located chiasmata. Hypotheses on the origin of the maternal age effect are critically reviewed. One model is presented that relates to altered cell cycle and protein phosphorylation in oocytes of aged mammals and accounts for most of the observed data in humans and in experimental studies. Aneuploidy may thus involve a predetermined component but is possibly also influenced by extrinsic factors reducing oocyte quality or depleting the oocyte pool precociously. Areas of future research are proposed to elucidate (i) the significance of early disturbances in the prenatal ovary, (ii) parameters diminishing the quality of oocytes in dictyate stage, and (iii) mechanisms enabling oocytes to process all chromosomal configurations successfully during later stages of oogenesis. Studies with newly developed and existing animal models appear indispensable to identify exposures affecting chromosome disjunction during meiosis, especially in the aging female.
Environ Mol Mutagen 1996
PMID:Parental age-related aneuploidy in human germ cells and offspring: a story of past and present. 890 81

The development of a bovine in vitro embryo production system where individual oocytes could be followed through to the morula or blastocyst stage would be of interest to several fields of study and would allow us to characterise developmentally competent oocytes and their corresponding follicular environment. Several studies have, however, reported significantly reduced embryo development when oocytes or embryos were cultured individually compared to in groups. The aim of this study was to establish such an embryo production system, with embryo development rates similar to that observed under control (grouped) conditions. This study showed that conservation of the oocyte/embryo medium densities generally employed for grouped culture does not facilitate embryo development if oocytes/embryos are cultured individually. However, individual oocytes could effectively undergo IVM/IVF/IVC to the expanded blastocyst stage with some small modifications to the standard protocol. Individual IVF was effective if carried out in either 100 microliters of medium in wells or in 50 microliters droplets. Individual IVC, if carried out in 10 or 20 microliters droplets of SOF with FCS added at either 0 or 24 hr, was effective in terms of blastocyst yields but 20 microliters droplets did yield significantly fewer hatched blastocysts compared to grouped controls (p < 0.05). An entirely individual embryo production system was effective when it included individual IVM in 10 microliters droplets of M199 + 10 ng/ml EGF resulting in day 8 blastocyst yields not significantly different from controls (38% vs. 35% respectively). The use of 10% FCS during individual IVM appeared, at least under our experimental conditions, to be detrimental to subsequent development. The uses of an individual system for embryo production are many and varied. The results of this study show clearly that a large proportion of bovine oocytes can develop to the blastocyst stage when matured, fertilized, and cultured individually. This opens the way for studies regarding the quality of specific oocytes in such a way as will greatly improve our understanding of the events of late folliculogenesis.
Mol Reprod Dev 1996 Oct
PMID:In vitro production of bovine embryos using individual oocytes. 891 71

Regulatory effect of GH on follicular growth and development in the cow is well documented. The aim of this study was to investigate the role of GH on in vitro bovine oocyte maturation. Therefore bovine cumulus oocyte complexes (COCs) were cultured in M199 without FCS and gonadotropins and in the presence of 10, 100, or 1,000 ng/ml bovine GH (NIH-GH-B18). The COCs were incubated at 39 degrees C in a humidified atmosphere with 5% CO2 in air and nuclear stage was assessed after 2, 4, 8, 16, 22, and 24 hr of incubation using DAPI staining. To assess the effect of GH on developmental capacity of the oocytes, COCs were incubated in the presence of GH for 22 hr, followed by IVF and in vitro embryo culture. Cultures without GH served as controls. For subsequent development, the embryos were cultured in M199 supplemented with 10% FCS on a monolayer of BRL cells. Embryos were scored morphologically and the efficiency of the culture system was evaluated as (1) the percentage of cleaved embryos 4 days after IVF, (2) the percentage of blastocysts on day 9 expressed on the basis of the number of oocytes at the onset of culture, and (3) the percentage of hatched blastocysts on day 11 expressed on the basis of the total number of blastocysts present at day 9. GH (100 and 1,000 ng/ml) significantly accelerated nuclear maturation (P < 0.001). At 4 and 8 h the percentage of oocytes in GV stage after GH treatment (54% and 19%) was significantly lower than the control (64% and 41%). Similarly at 16 and 22 h the percentage of oocytes in MII stage was significantly higher in the GH-treated group; (58% and 77%) and (46% and 62%) for GH and control respectively. The number of oocytes in MII beyond 22 hr of culture did not differ; 100 and 1,000 ng/ml GH induced significant cumulus expansion (P < 0.05), which was not observed in the absence of GH. Addition of 100 and 1,000 ng/ml GH during maturation significantly (P < 0.01) enhanced subsequent cleavage rate from (64% and 67%) in control to (75% and 81%) in GH-treated group; embryonic development in terms of day 9 blastocyst formation was also significantly increased in the presence of GH (29% and 34%) compared to the control (18% and 24%). The hatchability of the blastocysts was not influenced by GH. From the present data, it can be concluded that GH present during IVM has a beneficial effect on subsequent development.
Mol Reprod Dev 1996 Nov
PMID:In vitro maturation of bovine oocytes in the presence of growth hormone accelerates nuclear maturation and promotes subsequent embryonic development. 891 49

In this study we evaluated nuclear and ooplasmic maturation of prepuberal calf oocytes to determine a possible cause for their low developmental competency. Calf oocytes resumed meiosis and arrested at the MII stage at rates similar to that of adult animals; however, zygotes derived from calf oocytes cleaved and developed at significantly lower rates. Ooplasmic maturation was assessed during oocyte maturation and fertilization. Transmission electron microscopy revealed that a majority of calf oocytes exhibited some delay in organelle migration and redistribution following maturation. Immunofluorescence microscopy showed that following IVF, a higher percentage of calf oocytes had abnormal chromatin and microtubule configurations than those of adult cattle. These anomalies were characterized by delayed formation of sperm aster and asynchronous pronuclear formation. Microfluorometry was used to characterize the Ca2+ responses of calf oocytes to the addition of agonists or after IVF. The addition of thimerosal demonstrated the presence of Ca2+ stores in calf oocytes. Injection of near threshold concentrations of inositol 1,4,5-trisphosphate (InsP3), used to test the sensitivity of the InsP3R, released significantly less Ca2+ in calf than in cow oocytes, whereas higher concentrations of InsP3 (500 microM) released maximal [Ca2+]i in both oocytes. These results suggested that the Ca2+ content of intracellular stores was similar, but the sensitivity of the InsP3R may be different. Following insemination, calf oocytes exhibiting [Ca2+]i oscillations displayed comparable amplitude and intervals to cow oocytes; however, a significantly higher number of fertilized calf oocytes failed to show oscillations. Our findings suggest that the low developmental competence of calf oocytes can be attributed, at least in part, to incomplete or delayed ooplasmic maturation.
Mol Reprod Dev 1996 Dec
PMID:Evaluation of developmental competence, nuclear and ooplasmic maturation of calf oocytes. 895 91

Co-culture remains a common method to support the development of bovine embryos, derived from IVM/IVF procedures. However, the mechanism by which somatic cells confer their benefit to the developing embryo remains undetermined. This study therefore analysed the changes made to the culture medium TCM-199, used in bovine embryo co-culture systems, by somatic cells and determined the effects of specific changes in medium composition on bovine embryo development in culture. Bovine oviduct epithelial (BOE), Buffalo rat liver (BRL) and fibroblast (3T3) cells were compared. The concentrations of glucose, L-lactate, pyruvate, amino acids, NH4+, H+ and the gas tensions of O2 and CO2 were measured in TCM-199 supplemented with 10% fetal calf serum (FCS) prior to and directly following 48 h incubation periods with each cell type. All three somatic cell types modified the carbohydrate composition of the media in a similar manner with the greatest changes made by the BOE cells. Notable alterations were an increase in the levels of L-lactate and pyruvate and a reduction in glucose concentration, which in the case of the BOE cells, fell from 5.55 mM to 2.67 mM. In order to determine the relevance of such changes in carbohydrate concentrations on bovine embryo development, modifications were made to carbohydrate levels in synthetic oviduct fluid (SOF) medium and their effect on blastocyst development in vitro assessed. In SOF medium supplemented with amino acids and BSA (SOFaa), significantly more zygotes developed to the blastocyst stage (64%; P < 0.01) than in SOFaa medium with the concentrations of glucose, D/L-lactate and pyruvate equivalent to those in TCM-199 (11%). Interestingly, when the levels of carbohydrates in SOFaa mimicked those present in TCM-199 following a 48 h incubation with BOE cells, 57% of zygotes reached the blastocyst stage. This improvement was ascribed to the reduction in glucose and increases in D/L-lactate and pyruvate concentrations in the culture system. Results from this study demonstrate that BOE cells create an environment favourable to embryonic development. The analysis of media samples by enzymatic methods meant that only the biologically active L-isomer of lactate was quantified. However, in SOFaa, both the L-isomer and inactive D-isomer are present in equimolar amounts. As such, culture media in which D/L-lactate syrup is used actually contain only 50% biologically active lactate meaning that all D/L-lactate concentrations are reported at twice the effective concentration. Therefore the effect of D/L-lactate concentration on blastocyst development was subsequently determined in this study. Blastocyst development was poor (24-36%) until the total D/L-lactate was present in the culture system at concentrations equal to or greater than 0.82 mM. However, blastocyst cell numbers remained low (60.1 +/- 6.9 - 78.5 +/- 6.6) until a total D/L-lactate concentration of 3.3 mM. This data reinforces that embryo morphological appearance is not sensitive enough to be used as the sole criterion for assessing embryo development.
Mol Reprod Dev 1997 Feb
PMID:Modifications made to culture medium by bovine oviduct epithelial cells: changes to carbohydrates stimulate bovine embryo development. 902 46

In vitro oocyte maturation followed by in vitro fertilization (IVM/IVF) success in the domestic cat remains inferior to commonly studied livestock or laboratory species. The objectives here were (1) to histologically assess atresia status of freshly excised follicle/oocyte complexes, and (2) to evaluate taphonomic change (deterioration after excision) of these complexes after ovarian cold storage for up to 48 h. After excision of 50 ovarian pairs, one ovary was preserved immediately and the other stored in phosphate buffered saline (4 degrees C) for 4, 8, 12, 24, or 48 h before fixation and examination. Ovaries were classified as luteal if prominent corpora lutea (CL) were present or as follicular if antral follicles and no CL were present. Two classes of follicle-oocyte complexes (preantral and antral) were microscopically evaluated. Of the 2,280 complexes examined, 64.3% demonstrated clear evidence of slight to severe degeneration, with various stages being described and photographed for the first time. There was no histological evidence indicating distinctive morphological differences between oocytes recovered from follicular versus luteal donors. Storage of whole ovaries in cold saline inhibited taphonomic changes for 48 h after excision. In summary, there is marked variability in the number and quality of follicle populations in cat ovaries. A high percentage of full-sized follicular oocytes are undergoing atresia at any given time. However, additional gross degeneration as a result of cold-storage appears modest for up to 48 h. Nonetheless, this high level of natural atresia in the cat likely contributes to comparatively lower IVM/IVF success than in other species.
Mol Reprod Dev 1997 Feb
PMID:Follicle-oocyte atresia and temporal taphonomy in cold-stored domestic cat ovaries. 902 50

Bovine oocytes were matured, fertilized, and cultured (TCM 199 with serum and co-culture) in vitro (IVMFC) with addition, during different phases of the procedure, of antioxidants: superoxide dismutase (SOD) and reduced glutathione (GSH). The addition of SOD (1,500 or 3,000 IU/ml) did not improve proportions of oocytes undergoing cleavage or the development of embryos to morula and blastocyst stages. The cleavage rates were significantly lower than in the control group (CTR 57.5%) when SOD was present during the insemination interval (IVF) or throughout the entire procedure (IVMFC). Thus when the lower concentration was present for IVF and IVMFC, 35.1% and 36.4% of inseminated oocytes cleaved (P < 0.01 compared to CTR) and cleavage results with the higher concentration during IVF and IVMFC were 38.5% and 29.2% (P < 0.025 and P < 0.001 compared to CTR, respectively). Significant improvements in proportions of oocytes undergoing cleavage (84.5% vs. 57.0%, P < 0.001) and morula/blastocyst development (33.3% vs. 13.9%, P < 0.005) were achieved when GSH (1 mM) was added to the culture medium. In a defined medium for culture (mSOF and BSA) the presence of SOD (3,000 IU/ml) was ineffective, but in a defined medium supplemented with GSH (1 mM) at day 6 postinsemination (i.e., when 90% of developing embryos were in 8-16 cell stages), development to the morula and blastocyst stages was supported for 35.5% of cultured oocytes (P < 0.005 compared to 19.2% for CTR). These data suggest that bovine embryos are sensitive to oxidative stress and that medium supplementation with the radical scavenger glutathione can improve embryo development in vitro.
Mol Reprod Dev 1996 Apr
PMID:Improvement in bovine embryo production in vitro by glutathione-containing culture media. 905 34

As part of our research program on biochemical markers of sperm maturity, we have studied sperm creatine kinase (CK) and lactate dehydrogenase (LDH) concentrations and the isoform ratios of the CK-M [% CK-M/(CK-M + CK-B)] and LDH-X [% LDH-X/(LDH-X + LDH-a)] in 50 oligospermic and 95 normospermic men [corrected]. Because the synthesis of LDH-X is initiated in early spermatogenesis, and that of CK-M commences in late spermiogenesis simultaneously with cytoplasmic extrusion, we proposed two working hypotheses:(1) LDH and CK concentrations reflect the retained cytoplasm in sperm, thus the activities of both enzymes will be related and will be higher in oligospermic specimens, which have a higher incidence of immature spermatozoa; and (2) because in normally developed sperm both LDH-X and CK-M are present, there will be a correlation between LDH-X and CK-M ratios in the mature sperm populations. However, among men with immature sperm samples with late spermiogenetic defect and diminished CK-M ratios, there will be two groups: one which completed spermatogenesis prior to spermiogenetic failure (normal LDH-X and diminished CK-M ratios), and another group with defects in both spermatogenesis and spermiogenesis (low LDH-X and diminished CK-M ratios). Because of this heterogeneity, LDH-X ratios will be a poor predictor of sperm maturity. The data support the hypotheses: (1) LDH and CK concentrations were higher in oligospermic vs. normospermic men (P < 0.001). (2) The LDH and CK concentrations were related (r = 0.65, P < 0.001, N = 145), and there were inverse correlations between CK, LDH, LDH-X, or CK-M ratios vs. sperm concentrations (P < 0.001 in all four). (3) The CK-M and LDH-X ratios were different between the oligospermic and normospermic groups (P < 0.001), although the means of the LDH-X ratios were narrower (LDH-X:1:1.3; CK-M:1:1.9). (4) Dividing the 145 samples by the cut-off value of mean minus 1 SD of the CK-M and LDH-X ratios (11% and 32%, respectively) demonstrated that the CK-M ratios discriminated better than LDH-X ratios between the samples with mature and immature sperm. These data on the biochemical markers of early and late spermatogenesis support the studies in which CK better reflected sperm quality than LDH or LDH-X (Orlando et al., 1994: Int J Androl 17:13-18) and the > 10% sperm CK-M ratio predicted with a rate of 30.4% per cycle in the occurrence of pregnancies in a blinded study of 84 IVF couples (Huszar et al., 1992: Fertil Steril 57:882-888).
Mol Reprod Dev 1996 Apr
PMID:Biochemical markers of early and late spermatogenesis: relationship between the lactate dehydrogenase-X and creatine kinase-M isoform concentrations in human spermatozoa. 905 41


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>