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Biomedical subjects

M Teruel

Publications and source records attributed to M Teruel.

10 recordsLinked to original sources
PubMed2005

Influence of different doses of progesterone treatments on ovarian follicle status in beef cows.

To determine a dose of progesterone (P4) that allow ovarian follicular wave control, Aberdeen Angus cows were randomly assigned into four groups: T600 (n=5), 600 mg of P4/day; T400 (n=5), 400 mg of P4/day; T200 (n=4), 200mg of P4/day and Control (n=4) (excipient only). Progesterone was injected from day 3 to 9 of estrous cycle. Ultrasonographies and blood sample collections were performed daily from day 2 to 10 and on day 15 of the estrous cycle. Additionally, an ultrasonographic study was conducted on day 13. Progesterone concentrations were different among all groups (P<0.01). The diameter of the dominant follicle was greater for control than for T200, T400 and T600 groups (P<0.01); there was no difference between T200 and T400 (P>0.05), but they had a greater diameter follicle than the T600 group (P<0.01). The growth rate of the dominant follicle between day 3 and 7 of estrous cycle was greater for control group (1.63+/-0.3 mmday(-1)) than for T200 (0.56+/-0.19 mmday(-1), P<0.05), T400 (0.6+/-0.23 mmday(-1), P<0.05) and T600 (0.11+/-0.13 mmday(-1), P<0.01) groups. The mean number of class I follicles (3-4mm) per day for the entire experimental period was less for the control group than for T200 (P<0.05), T400 and T600 (P<0.01) groups (3.7+/-1.3; 5.3+/-1.3; 6.6+/-1.8 and 8.1+/-1.9, respectively). The mean number for the T200 group was less than for T600 (P<0.05) and similar for T400 and T600 groups (P>0.05). The number of class III follicles was greater for control group than for the other groups (P<0.01). T200 and T400 groups had similar numbers of class III follicles (P>0.05) and both had greater numbers of follicles than the T600 group (P<0.05). The diameter of the corpus luteum of the T600 group (15.8+/-1.6 mm) was less than for control (21.0+/-2.5 mm, P<0.01), T200 (19.3+/-2.7 mm, P<0.01) and T400 (20.0+/-2.2 mm) groups (P<0.05). The mean diameter of corpus luteum of T200 was similar to T400 (P>0.05), but different from the control group (P<0.05). In conclusion, the daily intramuscular administration of 200mg or more of progesterone from day 3 to 9 of the estrous cycle indicates that plasma concentrations of progesterone can be used to modify the pattern of follicular development during the follicular wave. From day 5 of the estrous cycle, progesterone concentrations greater than 15 ng/ml (T600 group: 600 mg/day of progesterone from day 3 to 9 of the estrous cycle) inhibit dominant follicle development, increase the class I follicle populations (3-4 mm) and diminish the development of the corpus luteum.

Animals↗
PubMed2004

The odd-even effect in mitotically unstable B chromosomes in grasshoppers.

The odd-even effect, by which B chromosomes are more detrimental in odd numbers, has been reported in plants and animals. In grasshoppers, there are only a few reports of this effect and all were referred to as traits related to the formation of aberrant meiotic products (AMPs). Here we review the existing information about B chromosome effects on AMPs, chiasma frequency and the number of active nucleolus organizer regions (NORs) per cell. Polysomy for A chromosomes and B chromosomes are two kinds of chromosome polymorphism frequently found in grasshoppers. In some aspects, e.g. meiotic behaviour and mitotic instability leading to individual mosaicism (in the case of mitotically unstable Bs), polysomic As show similar characteristics to B chromosomes. In fact, polysomy is regarded as one of the main mechanisms for B chromosome origin. Here we review some features of meiotic behaviour in known cases of polysomy and mitotically unstable Bs in grasshoppers, in looking for possible causes for the odd-even effect. In all these traits, the odd-even effect was apparent, although its appearance was not universal in any case, with variation among species or populations within the same species. The equational division and lagging of the extra chromosomes, when univalents, could favour the appearance of abnormal meiotic products, and the formation of bivalents, when there are two or more extra chromosomes, inhibits this process. Therefore, the odd-even effect might be a consequence of the concomitant operation of both aspects of extra chromosome meiotic behaviour. The possibility that the odd-even effect might result from an increase in cell stress generated by odd numbers is suggested.

Animals↗
PubMed2000

Localized biphasic changes in phosphatidylinositol-4,5-bisphosphate at sites of phagocytosis.

Phagocytosis requires localized and transient remodeling of actin filaments. Phosphoinositide signaling is believed to play an important role in cytoskeletal organization, but it is unclear whether lipids, which can diffuse along the membrane, can mediate the focal actin assembly required for phagocytosis. We used imaging of fluorescent chimeras of pleckstrin homology and C1 domains in live macrophages to monitor the distribution of phosphatidylinositol-4,5-bisphosphate (4,5-PIP(2)) and diacylglycerol, respectively, during phagocytosis. Our results reveal a sequence of exquisitely localized, coordinated steps in phospholipid metabolism: a focal, rapid accumulation of 4,5-PIP(2) accompanied by recruitment of type Ialpha phosphatidylinositol phosphate kinase to the phagosomal cup, followed by disappearance of the phosphoinositide as the phagosome seals. Loss of 4,5-PIP(2) correlated with mobilization of phospholipase Cgamma (PLCgamma) and with the localized formation of diacylglycerol. The presence of 4, 5-PIP(2) and active PLCgamma at the phagosome was shown to be essential for effective particle ingestion. The temporal sequence of phosphoinositide metabolism suggests that accumulation of 4,5-PIP(2) is involved in the initial recruitment of actin to the phagocytic cup, while its degradation contributes to the subsequent cytoskeletal remodeling.

Actins↗
PubMed2000

Spatial sensing in fibroblasts mediated by 3' phosphoinositides.

The directed movement of fibroblasts towards locally released platelet-derived growth factor (PDGF) is a critical event in wound healing. Although recent studies have implicated polarized activation of phosphoinositide (PI) 3-kinase in G protein-mediated chemotaxis, the role of 3' PI lipids in tyrosine kinase-triggered chemotaxis is not well understood. Using evanescent wave microscopy and green fluorescent protein-tagged Akt pleckstrin homology domain (GFP-AktPH) as a molecular sensor, we show that application of a shallow PDGF gradient triggers a markedly steeper gradient in 3' PI lipids in the adhesion zone of fibroblasts. Polar GFP-AktPH gradients, as well as a new type of radial gradient, were measured from front to rear and from the periphery to the center of the adhesion zone, respectively. A strong spatial correlation between polarized 3' PI production and rapid membrane spreading implicates 3' PI lipids as a direct mediator of polarized migration. Analysis of the temporal changes of 3' PI gradients in the adhesion zone revealed a fast diffusion coefficient (0.5 microm(2)/s) and short lifetime of 3' PIs of <1 min. Together, this study suggests that the tyrosine kinase-coupled directional movement of fibroblasts and their radial membrane activity are controlled by local generation and rapid degradation of 3' PI second messengers.

3T3 Cells↗
PubMed2000

Growth factors and embryo development.

In this review are cited and discussed the possible roles of growth factors on preimplantation embryo development of different species. In first term, is considered the mRNA detection in early stages of development. The distribution pattern was not uniform for the different peptides evaluated. For some of them, the mRNAs are detected at the oocyte stage and the level declines to the blastocyst stage, which suggests a maternal origin for them. For others, the level increased from 2-4 cells to blastocyst stage. On the other hand, transcripts of growth factor receptors have been detected in preimplantation embryos. This suggests that growth factors of maternal or embryo origin interact with specific receptors on preimplantation embryo surface and regulate the early development. On the other hand, culture media supplemented with different growth factors have been used to study the possible effects on in vitro development. Some investigators have found no effect. Others, however, have demonstrated changes in protein synthesis, cell number, differentiation and hatching processes. Embryo development modulation by growth factors probably involves a balance between stimulatory and inhibitory effects, although works are needed to determine the precise roles played by these polypeptides during early stages of mammalian development.

Animals↗
PubMed1997

Effect of embryo density and growth factors on in vitro preimplantation development of mouse embryos.

Embryo development depends on maternal and embryonic factors that may regulate genetic programs in early development. Effects of growth factors on proliferation, differentiation and morphogenesis along embryogenesis have been documented. However, studies have not established the role of growth factors in the preimplantational period. The purpose of this study was to investigate the possible effects of growth factors and embryo density on mouse preimplantation development in vitro. Two- and eight-cell CF-1 embryos were cultured individually or in groups of ten in HTF medium, alone or with EGF, TGF-beta 1 and IGF-I. Cleavage rate varied greatly with growth factors and increased significantly when eight-cell embryos were cultured in groups. On the other hand, when two-cell embryos were cultured in groups, the cleavage rate was slower than that obtained when embryos were individually cultured. The differentiation rate increased significantly in two-cell embryos cultured in groups (p < 0.05). EGF, TGF-beta 1 and IGF-I increased differentiation rates significantly in two-cell embryos individually cultured for 68 hours. The combination of EGF and TGF-beta 1 increased the differentiation rates significantly. The other combinations were not effective in modifying this parameter. Hatching rates increased in embryos cultured in groups (p < 0.05). TGF-beta 1 decreased this parameter significantly in two- or eight-cell embryos cultured in groups (p < 0.05). The data described in this report suggest that preimplantational mouse embryos produce some factor or factors that enhance its development, specially the differentiation and hatching rates. However, a functional role for polypeptide growth factors during preimplantational development has to be determined.

Animals↗
PubMed1994

Assessment of the wheal size and skin blood flow of the erythema induced by histamine and its modification with cetirizine and ebastine: a crossover, double-blind study.

In order to assess the antihistaminic power of cetirizine and ebastine, we designed a randomized, double-blind, crossover study, measuring their capacity to modify skin blood flow induced by a histamine prick test. The vasomotor response was compared using a laser Doppler flowmeter. Two hours after intake of the antihistaminic drug, there were significant differences between both drugs: at 4 h, the antihistaminic effect of cetirizine persists, whereas ebastine only showed moderate activity. The reduction of the cutaneous blood flow values (CBFV) showed good activity in both groups, but cetirizine was more potent and showed faster activity than ebastine.

Adolescent↗
PubMed1989

Plasma sex steroids and SHBG in patients with breast cancer and their relation to tumor oestrogen-dependency.

In order to evaluate the possible role of sex steroids in breast cancer and their relation to the presence of oestradiol receptors (ER), ER were quantified in 112 breast adenocarcinomas and 14 benign tumours. The sex hormones of the patients were determined in plasma: oestradiol (E2), progesterone, testosterone, androstenedione, as well as SHBG and gonadotrophins. The ER were evaluated in cytosolic and nuclear fractions. Steroids and gonadotrophins were determined by RIA. SHBG was determined by following a procedure of saturation with tritiated dihydrostestosterone. The mean levels of E2 in postmenopausal women with breast cancer was found to be significantly higher than of the control group. However, no significant variations for the rest of the steroids were seen among the patients with breast cancer and the control group or benign tumour. Nor was any relation found between the presence of ER and the hormonal steroids studied or SHBG. It is suggested that the possible influence of the sex steroids in the etiopathogenesis of breast cancer might be due to the greater production accompanied by a parallel metabolic clearance that would maintain their plasma levels.

Adenocarcinoma↗