976 resultados para Triatomine embryo extract


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Successful implantation is still the limiting step in IVF. We hypothesized that maternal plasma concentrations of certain cytokines at the time of embryo transfer could predict the likelihood of successful implantation and pregnancy. sIL-2R, IL-6, LIF, and MMP2 concentrations were measured in plasma from 160 IVF patients (natural and stimulated IVF cycles) on the morning of the embryo transfer (ET0) and 14days later (ET+14). Patients were ultimately subdivided into four groups depending on the IVF treatment outcome (pregnancy failure, biochemical pregnancy, first-trimester miscarriage and normal term delivery). In natural and stimulated IVF cycles at ET0, sIL-2R concentrations were threefold higher in biochemical pregnancies than in pregnancy failures (P=0.020), and in natural cycles only, 2.5-fold higher in normal term deliveries than in pregnancy failures (P=0.023). Conversely, in natural and stimulated IVF cycles at ET0, LIF concentrations were one third lower in biochemical pregnancies/first-trimester miscarriages compared with pregnancy failures (P=0.042). We suggest that high sIL-2R and low LIF concentrations in maternal plasma on the morning of the embryo transfer might be associated with increased risks of early pregnancy loss, while a basal level of sIL-2R is necessary for normal term delivery outcome. Both cytokine measurements might therefore be useful in the management of IVF patients, and modulation of their concentrations could be investigated as a therapeutic alternative for women with abnormal concentrations at the time of embryo transfer.

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The expression of substance P (SP) was studied in sensory neurons of developing chick lumbosacral dorsal root ganglia (DRG) by using a mixture of periodic acid, lysine and paraformaldehyde as fixative and a monoclonal antibody for SP-like immunostaining. The first SP-like-immunoreactive DRG cells appeared first at E5, then rapidly increased in number to reach a peak (88% of ganglion cells) at E8, and finally declined (59% at E12, 51% after hatching). The fall of the SP-like-positive DRG cells resulted from two concomitant events affecting a subset of small B-neurons: a loss of neuronal SP-like immunoreactivity and cell death. After one hindlimb resection at an early (E6) or late (E12) stage of development (that is before or after establishment of peripheral connections), the DRG were examined 6 days later. In both cases, a drastic neuronal death occurred in the ispilateral DRG. However, the resection at E6 did not change the percentage of SP-like-positive neurons, while the resection at E12 severely reduced the proportion of SP-like-immunoreactive DRG cells (25%). In conclusion, connections established between DRG and peripheral target tissues not only promote the survival of sensory neurons, but also control the maintenance of SP-like-expression. Factors issued from innervated targets such as NGF would support the survival of SP-expressing DRG cells and enhance their SP content while other factors present in skeletal muscle or skin would hinder SP expression and therefore lower SP levels in a subset of primary sensory neurons.

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Animals and plants are associated with symbiotic microbes whose roles range from mutualism to commensalism to parasitism. These roles may not only be taxon-specific but also dependent on environmental conditions and host factors. To experimentally test these possibilities, we drew a random sample of adult whitefish from a natural population, bred them in vitro in a full-factorial design in order to separate additive genetic from maternal environmental effects on offspring, and tested the performance of the resulting embryos under different environmental conditions. Enhancing the growth of symbiotic microbes with supplemental nutrients released cryptic additive genetic variance for viability in the fish host. These effects vanished with the concurrent addition of the water mould Saprolegnia ferax. Our findings demonstrate that the heritability of host fitness is environment-specific and critically depends on the interaction between symbiotic microbes.

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Selostus: Glysiinin ja alaniinin vaikutus CR1aa-liuoksessa viljeltyyn kumulussolullisen ja -soluttoman naudanalkion kehitykseen

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Calbindin D-28k is a calcium-binding protein which is not expressed by dorsal root ganglion cells cultured from 6-day-old (E6) chick embryos. When soluble muscle extracts from embryos at E11, E18 or chickens 2 weeks after hatching were added immediately after seeding, dorsal root ganglia cells grown at E6 displayed neuronal subpopulations expressing calbindin immunoreactivity with time; the effect of muscle extract on the percentage of calbindin-immunoreactive dorsal root ganglia cells followed a dose-response curve. When muscle extract was added to cultures after a 3 day delay, the percentage of calbindin-expressing neurons was unchanged. The effect produced by muscle extract and, to a lesser degree, skin extract on the appearance of calbindin-positive neurons was not reproduced by brain or liver extracts while all four exerted a trophic action on cultured neurons. Hence it is assumed that muscle extract contains a factor which produces an inductive effect on the initiation of calbindin-expression by uncommitted subpopulations of sensory neurons rather than a trophic influence on the selective survival of covertly committed neuronal subpopulations. The fact that muscle extract promoted calbindin expression by dorsal root ganglia cells in neuron-enriched as well as in mixed dorsal root ganglion cell cultures indicates that the factor would act directly on sensory neurons rather than indirectly through mediation of non-neuronal cells. Since the active muscular factor was non-dialysable, heat-inactivated, trypsin-sensitive and retained by molecular filters with a cut-off of 30 K, this factor is probably a protein.

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Selostus: Alkionsiirtojalostusohjelma "ASMO", sen tavoitteet ja yhteenveto alkuvalinnan tuloksista

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Glutamine synthetase (GS) catalyses the ATP-dependent formation of glutamine from glutamate and ammonia. To determine whether dorsal root ganglion (DRG) cells from chick embryos express the enzyme in vivo or in vitro, GS was detected by immunocytochemical reaction either in vibratome sections of DRG or in dissociated DRG cell cultures. The immunocytochemical detection of GS showed that in vivo the DRG taken from chick embryos at day 10 (E10), E14, E18 or from chickens after hatching were free of any GS-positive ganglion cells; in contrast, in neuron-enriched cultures of DRG cells grown in vitro at E10, virtually all the neuronal cells (98.6 +/- 1.0%) express GS at 3, 5 or 7 days of culture. In mixed DRG cell cultures, only 83.6+/-4.6% of the neurons displayed a GS-immunoreactivity. In both culture conditions, neither the presence of horse serum nor the age of the culture appeared to affect the percentage of neurons which displayed a GS-immunoreactivity. After [3H]glutamine uptake, radioautographs revealed that only 80% of the neurons were labelled in neuron-enriched DRG cell cultures while 96% of the neurons were radioactive in mixed DRG cell cultures. Furthermore the most heavily [3H]glutamine-labelled neurons were exclusively found in mixed DRG cell cultures. Combination of both immunocytochemical detection of GS and radioautography after [3H]glutamine uptake showed that strongly GS-immunostained neurons corresponded to poorly radioactive ones and vice versa. When skeletal muscle extract (ME) was added to DRG cell cultures, the number of GS-positive neurons was reduced to 77.5 +/- 2.5% in neuron-enriched cultures or to 43.6 +/- 3.8% in mixed DRG cell cultures; in both types of culture, the intensity of the neuronal immunostaining was depressed. Furthermore, combined action of ME and non-neuronal cells potentiates the enzyme repression exerted separately by ME or non-neuronal cells. Since GS-immunoreactivity is expressed in DRG cells grown in vitro, but not in vivo, it is suggested that microenvironmental factors influence the expression of GS. More specifically, the repression of GS by primary sensory neurons grown in vitro may be strongly induced by soluble factors present in skeletal muscle, and to a lesser extent in brain, and potentiated by non-neuronal cells.

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Primary sensory neurons which innervate neuromuscular spindles in the chicken are calbindin-immunoreactive. The influence exerted by developing skeletal muscle on the expression of calbindin immunoreactivity by subpopulations of dorsal root ganglion (DRG) cells in the chick embryo was tested in vitro in coculture with myoblasts, in conditioned medium (CM) prepared from myoblasts and in control cultures of DRG cells alone. Control cultures of DRG cells grown at the 6th embryonic day (E6) did not show any calbindin-immunostained ganglion cell. In coculture of myoblasts previously grown for 14 days, about 3% of calbindin-immunoreactive ganglion cells were detected while about 1% were observed in some cultures grown in CM. Fibroblasts from various sources were devoid of effect. Skin or kidney cells were more active than myoblasts to initiate calbindin expression by subpopulations of DRG cells in coculture or, to a lesser degree, in CM. The results suggest that cellular factors would rather induce calbindin expression in certain sensory neurons than ensure a selective neuronal survival.

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Previous studies showed a fetal sheep liver extract (FSLE), in association with LPS, injected into aged (>20 months) mice reversed the altered polarization (increased IL-4 and IL-10 with decreased IL-2 and IFN-gamma) in cytokine production seen from ConA stimulated lymphoid cells of those mice. Aged mice show a >60% decline in numbers and suppressive function of both CD4(+)CD25(+)Foxp3(+)Treg and so-called Tr3 (CD4(+)TGFbeta(+)). Their number/function is restored to levels seen in control (8-week-old) mice by FSLE. We have reported at length on the ability of a novel pair of immunoregulatory molecules, members of the TREM family, namely CD200:CD200R, to control development of dendritic cells (DCs) which themselves regulate production of Foxp3(+) Treg. The latter express a distinct subset of TLRs which control their function. We report that a feature of the altered Treg expression following combined treatment with FSLE and monophosphoryl lipid A, MPLA (a bioactive component of lipid A of LPS) is the altered gene expression both of distinct subsets of TLRs and of CD200Rs. We speculate that this may represent one of the mechanisms by which FSLE and MPLA alter immunity in aged mice.

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Distribution of myosin, tubulin and laminin immunoreactive cells in the area opaca of the young chick embryo (Stages 4-8 HH) was studied using immunofluorescence technique. For the three markers, the number of stained cells increased with the age of the blastoderm. Cells stained for tubulin and laminin, were distributed throughout the area opaca, showing no supracellular organization. On the contrary, the cells stained for myosin became organized in a ring surrounding the area pellucida. This pattern appeared at the stage 6. Such an heterogenous distribution of the markers suggests a functional diversification of the ectodermal cell monolayer forming at these early developmental stages the area opaca. This idea is also supported by the results of autoradiography for tritiated thymidin which showed that the edge cells did not synthetize DNA and consequently did not divide.

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Dissociated cerebral hemisphere cells from 4- to 7-day-old chick embryos were cultured either on a collagen or a polylysine substrate in a serum-containing medium. Neurons were characterized by the demonstration of acetylcholinesterase, the presence of D2/N-CAM glycoprotein and neurofilament proteins. The proliferation of neuronal precursor cells was shown by morphological observations, autoradiographic analysis and measurements of [3H]-thymidine incorporation. Neuronal precursors derived from the 6-day-old embryos showed the highest proliferative activity. Neuroblast proliferation was found to be dependent on the culture substrates (i.e. polylysine or collagen), which yielded either isolated cells or cell aggregates, and the latter favored the mitogenic effect.

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A procedure is described to regenerate plants from protoplasts of Brazilian citrus cultivars, after isolation, fusion and culture. Protoplasts were isolated from embryogenic cell suspension cultures and from leaf mesophyll of seedlings germinated in vitro. The enzyme solution for protoplast isolation was composed of mannitol (0.7 M), CaCl2 (24.5 mM), NaH2PO4 (0.92 mM), MES (6.15 mM), cellulase (Onozuka RS - Yakult, 1%), macerase (Onozuka R10 - Yakult, 1%) and pectolyase Y-23 (Seishin, 0.2%). Protoplast culture in liquid medium after chemical fusion lead to the formation of callus colonies further adapted to solid medium. Somatic embryo formation occurred spontaneously after two subcultures, on modified MT medium supplemented with 500 mg/L of malt extract. Well defined embryos were germinated in modified MT medium with addition of GA3 (2.0 muM) and malt extract (500 mg/L). Plant regeneration was also achieved by adventitious shoots obtained through direct organogenesis of not well defined embryos in modified MT medium with addition of malt extract (500 mg/L), BAP (1.32 muM), NAA (1.07 muM) and coconut water (10 mL/L). Plantlets were transferred to root medium. Rooted plants were transferred to a greenhouse for further adaptation and development.

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In IVF around 70% of embryos fail to implant. Often more than one embryo is transferred in order to enhance the chances of pregnancy, but this is at the price of an increased multiple pregnancy risk. In the aim to increase the success rate with a single embryo, research projects on prognostic factors of embryo viability have been initiated, but no marker has found a routine clinical application to date. Effects of soluble human leukocyte antigen-G (sHLA-G) on both NK cell activity and on Th1/Th2 cytokine balance suggest a role in the embryo implantation process, but the relevance of sHLA-G measurements in embryo culture medium and in follicular fluid (FF) are inconsistent to date. In this study, we have investigated the potential of sHLA-G in predicting the achievement of a pregnancy after IVF-ICSI in a large number of patients (n = 221). sHLA-G was determined in media and in FF by ELISA. In both FF and embryo medium, no significant differences in sHLA-G concentrations were observed between the groups "pregnancy" and "implantation failure", or between the groups "ongoing" versus "miscarried pregnancies". Our results do not favour routine sHLA-G determinations in the FF nor in embryo conditioned media, with the current assay technology available.

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OBJECTIVE: To compare the cumulative live birth rates obtained after cryopreservation of either pronucleate (PN) zygotes or early-cleavage (EC) embryos. DESIGN: Prospective randomized study. SETTING: University hospital. PATIENT(S): Three hundred eighty-two patients, involved in an IVF/ICSI program from January 1993 to December 1995, who had their supernumerary embryos cryopreserved either at the PN (group I) or EC (group II) stage. For 89 patients, cryopreservation of EC embryos was canceled because of poor embryo development (group III). Frozen-thawed embryo transfers performed up to December 1998 were considered. MAIN OUTCOME MEASURE(S): Age, oocytes, zygotes, cryopreserved and transferred embryos, damage after thawing, cumulative embryo scores, implantation, and cumulative live birth rates. RESULT(S): The clinical pregnancy and live birth rates were similar in all groups after fresh embryo transfers. Significantly higher implantation (10.5% vs. 5.9%) and pregnancy rates (19.5% vs. 10.9%; P< or = .02 per transfer after cryopreserved embryo transfers were obtained in group I versus group II, leading to higher cumulative pregnancy (55.5% vs. 38.6%; P < or = .002 and live birth rates (46.9% vs. 27.7%; P< or = .0001.Conclusion(s): The transfer of a maximum of three unselected embryos and freezing of all supernumerary PN zygotes can be safely done with significantly higher cumulative pregnancy chances than cryopreserving at a later EC stage.