Gretchen Jimenez - Academia.edu (original) (raw)
Papers by Gretchen Jimenez
Agu Fall Meeting Abstracts, Dec 1, 2003
Results from a shallow seismic reflection experiment in 2000 on the Salar de Uyuni at the souther... more Results from a shallow seismic reflection experiment in 2000 on the Salar de Uyuni at the southern end of the Bolivian Altiplano will be presented. This salar is the largest salt flat in the world (~130 km x 80 km) and is a remnant of the Quaternary paleolake Minchin/Tauca. Paleoshorelines of this lake mapped by GPS show marked deformation (Bills et al., GRL, 1994). The salar also shows evidence for both Quaternary volcanic activity and active faulting from Andean tectonics. The paleolake stratigraphy of the salar, therefore, may record neotectonic deformation from three different processes: (1) isostatic rebound from the evaporation of the deep lakes that have occupied this region periodically during Quaternary climate fluctuations, (2) active faulting along local/regional fault systems, and (3) regional uplift and/or tilting of the Andes. The seismic experiment was designed, in part, to determine the extent to which the Quaternary lake stratigraphy documents neotectonic deformation and, if possible, to separate the effects of the different processes. The seismic profiles were collected using IRIS PASSCAL instruments and a hammer source. The stratigraphy is imaged to a depth of at least 200 m at surprisingly high frequencies and can be tied to the 220 m deep paleoclimate corehole drilled by Baker et al. (Nature, 2001). One 130-km transect was collected across the entire E-W width of the salar. A second 50-km N-S transect crosses at the corehole. These profiles are limited by very low spatial sampling but clearly show that the shallow Quaternary lake deposits now dip to the east and north and are offset by sets of faults, particularly on the eastern side of the salar. The tilting of the stratigraphy conforms with the thickening of the young surficial salt layer to the east, although the shallowmost seismic data quality doesn't allow one to determine the youngest age of layers offset by the imaged faults. Current efforts are to separate out the isostatic rebound signature from the deformation from faulting.
Development (Cambridge, England), 1999
The Groucho corepressor mediates negative transcriptional regulation in association with various ... more The Groucho corepressor mediates negative transcriptional regulation in association with various DNA-binding proteins in diverse developmental contexts. We have previously implicated Groucho in Drosophila embryonic terminal patterning, showing that it is required to confine tailless and huckebein terminal gap gene expression to the pole regions of the embryo. Here we reveal an additional requirement for Groucho in this developmental process by establishing that Groucho mediates repressor activity of the Huckebein protein. Putative Huckebein target genes are derepressed in embryos lacking maternal groucho activity and biochemical experiments demonstrate that Huckebein physically interacts with Groucho. Using an in vivo repression assay, we identify a functional repressor domain in Huckebein that contains an FRPW tetrapeptide, similar to the WRPW Groucho-recruitment domain found in Hairy-related repressor proteins. Mutations in Huckebein's FRPW motif abolish Groucho binding and in...
[1991] Proceedings, Advanced Computer Technology, Reliable Systems and Applications, 1991
... Authors R Ordo?iez, E Diaz, G Jimenez, J Sevillano, J Madrid Grupo de Robotica y Procesado de... more ... Authors R Ordo?iez, E Diaz, G Jimenez, J Sevillano, J Madrid Grupo de Robotica y Procesado de Imagen Universidad de Sevilla Avda Reina Mercedes s/n 41012 SEVILLA SPAIN ... Primitive Unity or Primitive: Let be U = {ql ,..., qn.p} where ql, ._., qn,p are primitive elements. ...
IEEE 2002 28th Annual Conference of the Industrial Electronics Society. IECON 02, 2002
In mobile robots it is usual that the desired trajectory is memorized or previously generated. Wh... more In mobile robots it is usual that the desired trajectory is memorized or previously generated. When following a trajectory, there are several possibilities attending to the way in which the actual robot state can be related with the whole trajectory. One of them is the extension of the servosystem approach, usually called "trajectory tracking". This is the only possibility if
IEEE 2002 28th Annual Conference of the Industrial Electronics Society. IECON 02, 2002
This paper describes design and implementation of a waveform generator. The generator can be cont... more This paper describes design and implementation of a waveform generator. The generator can be controlled using an embedded computer, performing many different voltage patterns up to 400 V. This feature makes it a very versatile instrument, useful in a wide range of experiments. The system is based on a switching DC power supply (flyback converter), controlled by an on-board microcontroller.
V IEEE International Power Electronics Congress Technical Proceedings, CIEP 96, 1996
This paper introduces a novel technique for controlling current harmonics in power supply convert... more This paper introduces a novel technique for controlling current harmonics in power supply converter systems. A variable characteristics capacitive active filter is proposed and is used to control the AC current harmonics generated by a standard AC/DC converter with resistive load and a smoothing capacitor. The idea of the proposed filter is to use a combination of capacitors and switches
Virus Research, 1988
The antigenic structure of transmissible gastroenteritis (TGE) virus E2 glycoprotein has been def... more The antigenic structure of transmissible gastroenteritis (TGE) virus E2 glycoprotein has been defined at three levels: antigenic sites, antigenic subsites and epitopes. Four antigenic sites (A, B, C and D) were defined by competitive radioimmunoassay (RIA) using monoclonal antibodies (MAbs) selected from 9 fusions. About 20% (197) of the hybridomas specific for TGE virus produced neutralizing MAbs specific for site A, which was one of the antigenically dominant determinants. Site A was differentiated in three antigenic subsites: a, b and c, by characterization of 11 MAb resistant (mar) mutants, that were defined by 8, 3, and 3 MAbs, respectively. These subsites were further subdivided in epitopes. A total of 11 epitopes were defined in E2 glycoprotein, eight of which were critical for virus neutralization. Neutralizing MAbs were obtained only when native virus was used to immunize mice, although to produce hybridomas mice immunizations were made with antigen in the native, denatured, or mixtures of native and denatured form. All neutralizing MAbs reacted to conformational epitopes. The antigenic structure of the EZglycoprotein has been defined with murine MAbs, but the antigenic sites were relevant in the swine, the natural host of the virus, because porcine sera reacted against these sites. MAbs specific for TGE virus site C reacted to non-immune porcine sera. This reactivity was not directed against porcine immunoglobulins. These results indicated that TGE virus contains epitope(s) also present in some non-immunoglobulin component of porcine serum.
Proceedings of the National Academy of Sciences, 1992
The (3-globin locus control region (LCR) is characterized by erythroid-speciflc DNase I hypersens... more The (3-globin locus control region (LCR) is characterized by erythroid-speciflc DNase I hypersensitive sites and is involved in the chromatin organization, trancriptional potentiation, developmental regulation, and replication tming of the entire (-globin gene duster. When and how the LCR is first activated during erythropoiesis is not known. Here we analyze the chromatin structure of the LCR during early hematopoietic differentiation using nontransformed, multipotential, growth factor-dependent, murine hematopoietic progenitor cells. We show that LCR hypersensitive sites characteristic of erythroid cells are present in three independent multilineage progenitors (FDCP (factor-dependent cell, Paterson)-mix A4, B6SUtA, and LyD9] under conditions of selfrenewal. Induction of differentiation down a nonerythroid pathway causes a progressive loss of hypersensitivity in the LCR. These results show that the (3-globin LCR is in an active chromatin configuration prior to erythroid commitment and indicate a significant role for selective gene repression in lineage specification.
Postgraduate Medical Journal, 1997
A debilitated patient with liver cirrhosis and poor haemostasis had a severe lower gastrointestin... more A debilitated patient with liver cirrhosis and poor haemostasis had a severe lower gastrointestinal haemorrhage. A superior mesenteric arteriogram revealed an early persistent and promiment draining vein in the ileocolic artery. Two fragments of Spongostan and silk were used to embolise the bleeding artery and the haemorrhage ceased immediately. No infarction of the embolised area was observed and the bleeding was controlled.
Journal of General Virology, 1988
The antigenic relationship between a recently isolated porcine respiratory coronavirus (TLM 83) a... more The antigenic relationship between a recently isolated porcine respiratory coronavirus (TLM 83) and transmissible gastroenteritis (TGE) virus of swine was studied by neutralization, immunoblotting and radioimmunoassay (RIA) using TGE virus-specific monoclonal antibodies (MAbs) and polyclonal antibodies specific for both viruses. A complete two-way neutralization activity between the two viruses was found. Immunoblotting revealed cross-reactions between TLM 83 and TGE virus antigens at the level of the envelope protein (El), the nucleoprotein (N) and the peplomer protein (E2). By virus neutralization assays and RIA with TGE virus-specific MAbs, the presence of similar epitopes in the E1 and N proteins and in the neutralization-mediating antigenic site of the E2 protein were demonstrated. E2 protein-specific MAbs, without neutralizing activity and reacting with antigenic sites B, C and D (previously defined), failed to recognize TLM 83. These results indicated a close antigenic relationship and structural similarity between TLM 83 and TGE viruses and also suggested potential ways of differentiating between the two viruses.
Journal of General Virology, 1989
Three transmissible gastroenteritis (TGE) virus-specific T helper (Th) cell hybridomas have been ... more Three transmissible gastroenteritis (TGE) virus-specific T helper (Th) cell hybridomas have been generated from virus-primed BALB/c mice, by fusion with the thymoma BW5147. The hybridomas responded to purified u.v.-inactivated TGE virus with interleukin production and growth inhibition. TGE virus recognition by the hybridomas was restricted by the major histocompatibility complex : only splenocytes from syngeneic or semi-syngeneic mice were able to recognize the antigen. The three hybridomas were Thy 1.2 ÷, but did not express detectable levels of Lyt 1 or Lyt 2 antigens by fluorescent cell sorting analysis. Only one hybridoma (T. 1J. B5) expressed the L3T4 marker. These hybridomas had helper activity, as they were able to reconstitute in vitro the synthesis of TGE virus-specific antibodies by Th cell-depleted spleen cells from immune BALB/c mice. The antibodies that they induced specifically neutralized by 103-to 104-fold the infectivity of TGE virus, ruling out the possibility of inhibition of virus replication by interferon. These hybridomas could be very useful for identifying antigenic domains in TGE virus recognized by Th cells, which cooperate with B cells in the synthesis of neutralizing antibodies. Downloaded from www.microbiologyresearch.org by IP: 54.160.113.5 On: Fri, 27 May 2016 13:26:16 660 M. J. BULLIDO AND OTHERS
Journal of Ethnopharmacology, 2001
A total of 21 extracts derived from 17 different plant species collected in Venezuelan Amazons ha... more A total of 21 extracts derived from 17 different plant species collected in Venezuelan Amazons have been tested for the following biological activities: cardiovascular activity, brine shrimp lethality, and inhibitory effects on the hydrolysis of glucose-6-phosphate in intact and disrupted microsomes. Eight extracts diminished rat blood pressure with or without changes in heart rate. The fruit extract of Swartzia leptopetala and the leaf and twig extract of Connarus lambertii resulted in death of experimental animals. The majority of extracts (17 extracts) showed significant toxicity against Artemia salina. Concerning the hydrolysis of glucose-6-phosphate, better inhibitory effects were observed in intact microsomes than in disrupted ones for all the extracts, suggesting that these extracts intervene with variable potency in glucose-6-phosphate transport through the microsomal membrane.
Journal of Ethnopharmacology, 2001
It is well known that gingivitis is a bacterially-elicited inflammation of the marginal gingiva. ... more It is well known that gingivitis is a bacterially-elicited inflammation of the marginal gingiva. A number of chemical agents have been evaluated over the years with regard to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. Therefore, the effectiveness of a natural Mexican Sanguinaria extract (Polygonum a6iculare L.) against gingivitis, was assessed in 60 male dentistry students between the ages of 18 and 25 years. Over a period of 2 weeks, these students used the Sanguinaria extract (1 mg/ml) in oral rinse twice daily as a unique oral health measurement (no tooth-brushing was allowed). The O'Leary Plaque Index and the Lö e and Silness Gingivitis Index were recorded at baseline (day 0) in all the subjects. Also, a complete prophylaxis was performed after both indices were obtained. The antibacterial and antiinflammatory effects of the extract were evaluated on days 7, 11 and 14. The results showed that the Mexican Sanguinaria extract in oral rinse significantly decreased gingivitis from day 0 (x =1.056) to day 14 (x = 1.011) (P5 0.05). In contrast, a significant increase in dental plaque was observed from day 0 (x = 91.38) to day 14 (x = 98.69) (P5 0.05); however, the consistency of this plaque permitted its mechanical flushing easily. From this study, it is concluded that the Mexican Sanguinaria extract in oral rinse can be employed supportively in the therapy of gingivitis.
Journal of Enzyme Inhibition and Medicinal Chemistry, 2005
The in vivo and in vitro antiandrogenic activity of four aromatic esters 10a-10d, one aliphatic e... more The in vivo and in vitro antiandrogenic activity of four aromatic esters 10a-10d, one aliphatic ester 10e based on the pregna-4,16-diene-6, 20-dione structure and two aromatic 17c, 17d and two aliphatic valeroyloxy esters 17a, 17b based on the more saturated 4-pregnene-6,20-dione skeleton was examined. The biological activity of steroids 9, 10a-10e and 17a-17d, was determined using prostate glands from gonadectomized adult male golden hamsters. In the in vitro studies, the relative binding affinity of these steroids to cytoplasmic androgen receptor (AR) of hamster prostate was determined from, the corresponding IC50 values obtained from the competitive binding plots. The standards dihydrotestosterone (DHT) and cyproterone (CA) acetate used have displaced [3H]DHT from the AR with an IC50 value of 3.2 and 4.4 nM respectively. All steroidal compounds synthesized in this study showed a binding affinity for the androgen receptor, present in the cytosol from prostate hamster; compounds 10a-10c showed the highest affinities for this receptor. The in vivo experiments showed that all steroidal derivatives were subcutaneously active, since they decreased the weight of the prostate gland in gonadectomized hamsters treated with DHT, and are antagonists for the androgen receptor since they block the DHT-induced prostate weight gain. The derivatives having the more conjugated 4,16-pregnadiene-6, 20-dione system (10a-10c) exhibited a higher antiandrogenic activity than the corresponding steroids (17a-17d) based on the more saturated 4-pregnene-6,20-dione system.
Journal of Clinical Epidemiology, 1998
Objective: In the laparoscopic era choledocholithiasis diagnosis has be-Objective: To investigate... more Objective: In the laparoscopic era choledocholithiasis diagnosis has be-Objective: To investigate the association between type II diabetes and generalizated alveolar bone loss (GABL). come extremely important. The goal of this study was to develop a model for routine pre-operative screening, in order to determine the risk of choled-Design: A case-control study.
Journal of Allergy and Clinical Immunology, 2006
Development, 2008
RTK pathways establish cell fates in a wide range of developmental processes. However, how the pa... more RTK pathways establish cell fates in a wide range of developmental processes. However, how the pathway effector MAPK coordinately regulates the expression of multiple target genes is not fully understood. We have previously shown that the EGFR RTK pathway causes phosphorylation and downregulation of Groucho, a global co-repressor that is widely used by many developmentally important repressors for silencing their various targets. Here, we use specific antibodies that reveal the dynamics of Groucho phosphorylation by MAPK, and show that Groucho is phosphorylated in response to several RTK pathways during Drosophila embryogenesis. Focusing on the regulation of terminal patterning by the Torso RTK pathway, we demonstrate that attenuation of Groucho's repressor function via phosphorylation is essential for the transcriptional output of the pathway and for terminal cell specification. Importantly, Groucho is phosphorylated by an efficient mechanism that does not alter its subcellular localisation or decrease its stability; rather, modified Groucho endures long after MAPK activation has terminated. We propose that phosphorylation of Groucho provides a widespread, long-term mechanism by which RTK signals control target gene expression.
Cytogenetic and Genome Research, 2004
Rye B chromosomes (Bs) have strong parasitic effects on fertility. B carrying plants are less fer... more Rye B chromosomes (Bs) have strong parasitic effects on fertility. B carrying plants are less fertile than 0B ones, whereas the Bs have no significant effects on plant vigour. On the other hand, it has been reported that B transmission is under genetic control in such a way that H line plants transmit the Bs at high frequency, whereas the Bs in the low B transmission rate line (L) fail to pair at metaphase I and are frequently lost. In the present work we analyse variables affecting vigour and fertility considering not only the number of Bs of each plant, but also its H or L status and the B number of its maternal parent. Our results show that the Bs not only decrease female fertility of the B carrier, but the fertility of its progeny, with the exception of 0B plants coming from a 4B mother, which are the most fertile. In this way B chromosomes can be considered as a selective factor. Pollen abortion was higher in B carriers, in the progeny of B carriers and in H plants, but 4B plants coming from B carrying mothers produce less aborted pollen, indicating that a high B number is more deleterious if it is transmitted in the pollen grains. A similar result was obtained for endosperm quality estimated as grain weight, because it is negatively influenced by the Bs in 4B plants coming from a 0B mother. H plants were always less fertile than L ones, indicating that alleles increasing the loss of Bs in the L line will be probably selected as a defence of the A genome against the invasive Bs of the H line. Flower number is not affected by the Bs.
Animal Feed Science and Technology, 1999
The objective of this article is to offer some information about traditional practice regarding t... more The objective of this article is to offer some information about traditional practice regarding the use of the genus Buddleia in the Highlands of Chiapas, Mexico, with the aim of increasing its use as a potential fodder for sheep feeding in the area. Based on the indigenous Tzotzil Botanical Classification, three Buddleia groups were taxonomically identified. Group 1 includes the species Buddleia skutchii and Buddleia cordata, group 2, Buddleia americana and Buddleia crotonoides, and group 3, Buddleia parviflora and Buddleia nitida. Even though all these groups have been used as fodder, the most frequently used are the species in group 1, which are the most common species with the widest distribution patterns. Based on their chemical composition, the species of higher nutritional values were B. skutchii and B. crotonoides (crude protein (CP), 10.6% and 9.3%; neutral detergent fiber (NDF), 37.5% and 33.7%; in vitro dry matter digestibility (IVDMD), 75.9% and 58.2%; and digestible energy (DE), 3.3 and 2.5 Mcal/kg). The first one has been recommended for sheep feeding based on its high nutritional value. During an intake and digestibility trial, B. skutchii leaves substituted 50% of Kikuyo grass (Pennisetum clandestinum) without decreasing dry matter (DM) intake and digestibility. These results suggest that the systematic incorporation of B. skutchii into existing sheep production systems could 0377-8401/99/$ ± see front matter # 1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 7 -8 4 0 1 ( 9 9 ) 0 0 0 4 1 -3 markedly increase feed resources without higher pressure on pasture land. #
Agu Fall Meeting Abstracts, Dec 1, 2003
Results from a shallow seismic reflection experiment in 2000 on the Salar de Uyuni at the souther... more Results from a shallow seismic reflection experiment in 2000 on the Salar de Uyuni at the southern end of the Bolivian Altiplano will be presented. This salar is the largest salt flat in the world (~130 km x 80 km) and is a remnant of the Quaternary paleolake Minchin/Tauca. Paleoshorelines of this lake mapped by GPS show marked deformation (Bills et al., GRL, 1994). The salar also shows evidence for both Quaternary volcanic activity and active faulting from Andean tectonics. The paleolake stratigraphy of the salar, therefore, may record neotectonic deformation from three different processes: (1) isostatic rebound from the evaporation of the deep lakes that have occupied this region periodically during Quaternary climate fluctuations, (2) active faulting along local/regional fault systems, and (3) regional uplift and/or tilting of the Andes. The seismic experiment was designed, in part, to determine the extent to which the Quaternary lake stratigraphy documents neotectonic deformation and, if possible, to separate the effects of the different processes. The seismic profiles were collected using IRIS PASSCAL instruments and a hammer source. The stratigraphy is imaged to a depth of at least 200 m at surprisingly high frequencies and can be tied to the 220 m deep paleoclimate corehole drilled by Baker et al. (Nature, 2001). One 130-km transect was collected across the entire E-W width of the salar. A second 50-km N-S transect crosses at the corehole. These profiles are limited by very low spatial sampling but clearly show that the shallow Quaternary lake deposits now dip to the east and north and are offset by sets of faults, particularly on the eastern side of the salar. The tilting of the stratigraphy conforms with the thickening of the young surficial salt layer to the east, although the shallowmost seismic data quality doesn't allow one to determine the youngest age of layers offset by the imaged faults. Current efforts are to separate out the isostatic rebound signature from the deformation from faulting.
Development (Cambridge, England), 1999
The Groucho corepressor mediates negative transcriptional regulation in association with various ... more The Groucho corepressor mediates negative transcriptional regulation in association with various DNA-binding proteins in diverse developmental contexts. We have previously implicated Groucho in Drosophila embryonic terminal patterning, showing that it is required to confine tailless and huckebein terminal gap gene expression to the pole regions of the embryo. Here we reveal an additional requirement for Groucho in this developmental process by establishing that Groucho mediates repressor activity of the Huckebein protein. Putative Huckebein target genes are derepressed in embryos lacking maternal groucho activity and biochemical experiments demonstrate that Huckebein physically interacts with Groucho. Using an in vivo repression assay, we identify a functional repressor domain in Huckebein that contains an FRPW tetrapeptide, similar to the WRPW Groucho-recruitment domain found in Hairy-related repressor proteins. Mutations in Huckebein's FRPW motif abolish Groucho binding and in...
[1991] Proceedings, Advanced Computer Technology, Reliable Systems and Applications, 1991
... Authors R Ordo?iez, E Diaz, G Jimenez, J Sevillano, J Madrid Grupo de Robotica y Procesado de... more ... Authors R Ordo?iez, E Diaz, G Jimenez, J Sevillano, J Madrid Grupo de Robotica y Procesado de Imagen Universidad de Sevilla Avda Reina Mercedes s/n 41012 SEVILLA SPAIN ... Primitive Unity or Primitive: Let be U = {ql ,..., qn.p} where ql, ._., qn,p are primitive elements. ...
IEEE 2002 28th Annual Conference of the Industrial Electronics Society. IECON 02, 2002
In mobile robots it is usual that the desired trajectory is memorized or previously generated. Wh... more In mobile robots it is usual that the desired trajectory is memorized or previously generated. When following a trajectory, there are several possibilities attending to the way in which the actual robot state can be related with the whole trajectory. One of them is the extension of the servosystem approach, usually called "trajectory tracking". This is the only possibility if
IEEE 2002 28th Annual Conference of the Industrial Electronics Society. IECON 02, 2002
This paper describes design and implementation of a waveform generator. The generator can be cont... more This paper describes design and implementation of a waveform generator. The generator can be controlled using an embedded computer, performing many different voltage patterns up to 400 V. This feature makes it a very versatile instrument, useful in a wide range of experiments. The system is based on a switching DC power supply (flyback converter), controlled by an on-board microcontroller.
V IEEE International Power Electronics Congress Technical Proceedings, CIEP 96, 1996
This paper introduces a novel technique for controlling current harmonics in power supply convert... more This paper introduces a novel technique for controlling current harmonics in power supply converter systems. A variable characteristics capacitive active filter is proposed and is used to control the AC current harmonics generated by a standard AC/DC converter with resistive load and a smoothing capacitor. The idea of the proposed filter is to use a combination of capacitors and switches
Virus Research, 1988
The antigenic structure of transmissible gastroenteritis (TGE) virus E2 glycoprotein has been def... more The antigenic structure of transmissible gastroenteritis (TGE) virus E2 glycoprotein has been defined at three levels: antigenic sites, antigenic subsites and epitopes. Four antigenic sites (A, B, C and D) were defined by competitive radioimmunoassay (RIA) using monoclonal antibodies (MAbs) selected from 9 fusions. About 20% (197) of the hybridomas specific for TGE virus produced neutralizing MAbs specific for site A, which was one of the antigenically dominant determinants. Site A was differentiated in three antigenic subsites: a, b and c, by characterization of 11 MAb resistant (mar) mutants, that were defined by 8, 3, and 3 MAbs, respectively. These subsites were further subdivided in epitopes. A total of 11 epitopes were defined in E2 glycoprotein, eight of which were critical for virus neutralization. Neutralizing MAbs were obtained only when native virus was used to immunize mice, although to produce hybridomas mice immunizations were made with antigen in the native, denatured, or mixtures of native and denatured form. All neutralizing MAbs reacted to conformational epitopes. The antigenic structure of the EZglycoprotein has been defined with murine MAbs, but the antigenic sites were relevant in the swine, the natural host of the virus, because porcine sera reacted against these sites. MAbs specific for TGE virus site C reacted to non-immune porcine sera. This reactivity was not directed against porcine immunoglobulins. These results indicated that TGE virus contains epitope(s) also present in some non-immunoglobulin component of porcine serum.
Proceedings of the National Academy of Sciences, 1992
The (3-globin locus control region (LCR) is characterized by erythroid-speciflc DNase I hypersens... more The (3-globin locus control region (LCR) is characterized by erythroid-speciflc DNase I hypersensitive sites and is involved in the chromatin organization, trancriptional potentiation, developmental regulation, and replication tming of the entire (-globin gene duster. When and how the LCR is first activated during erythropoiesis is not known. Here we analyze the chromatin structure of the LCR during early hematopoietic differentiation using nontransformed, multipotential, growth factor-dependent, murine hematopoietic progenitor cells. We show that LCR hypersensitive sites characteristic of erythroid cells are present in three independent multilineage progenitors (FDCP (factor-dependent cell, Paterson)-mix A4, B6SUtA, and LyD9] under conditions of selfrenewal. Induction of differentiation down a nonerythroid pathway causes a progressive loss of hypersensitivity in the LCR. These results show that the (3-globin LCR is in an active chromatin configuration prior to erythroid commitment and indicate a significant role for selective gene repression in lineage specification.
Postgraduate Medical Journal, 1997
A debilitated patient with liver cirrhosis and poor haemostasis had a severe lower gastrointestin... more A debilitated patient with liver cirrhosis and poor haemostasis had a severe lower gastrointestinal haemorrhage. A superior mesenteric arteriogram revealed an early persistent and promiment draining vein in the ileocolic artery. Two fragments of Spongostan and silk were used to embolise the bleeding artery and the haemorrhage ceased immediately. No infarction of the embolised area was observed and the bleeding was controlled.
Journal of General Virology, 1988
The antigenic relationship between a recently isolated porcine respiratory coronavirus (TLM 83) a... more The antigenic relationship between a recently isolated porcine respiratory coronavirus (TLM 83) and transmissible gastroenteritis (TGE) virus of swine was studied by neutralization, immunoblotting and radioimmunoassay (RIA) using TGE virus-specific monoclonal antibodies (MAbs) and polyclonal antibodies specific for both viruses. A complete two-way neutralization activity between the two viruses was found. Immunoblotting revealed cross-reactions between TLM 83 and TGE virus antigens at the level of the envelope protein (El), the nucleoprotein (N) and the peplomer protein (E2). By virus neutralization assays and RIA with TGE virus-specific MAbs, the presence of similar epitopes in the E1 and N proteins and in the neutralization-mediating antigenic site of the E2 protein were demonstrated. E2 protein-specific MAbs, without neutralizing activity and reacting with antigenic sites B, C and D (previously defined), failed to recognize TLM 83. These results indicated a close antigenic relationship and structural similarity between TLM 83 and TGE viruses and also suggested potential ways of differentiating between the two viruses.
Journal of General Virology, 1989
Three transmissible gastroenteritis (TGE) virus-specific T helper (Th) cell hybridomas have been ... more Three transmissible gastroenteritis (TGE) virus-specific T helper (Th) cell hybridomas have been generated from virus-primed BALB/c mice, by fusion with the thymoma BW5147. The hybridomas responded to purified u.v.-inactivated TGE virus with interleukin production and growth inhibition. TGE virus recognition by the hybridomas was restricted by the major histocompatibility complex : only splenocytes from syngeneic or semi-syngeneic mice were able to recognize the antigen. The three hybridomas were Thy 1.2 ÷, but did not express detectable levels of Lyt 1 or Lyt 2 antigens by fluorescent cell sorting analysis. Only one hybridoma (T. 1J. B5) expressed the L3T4 marker. These hybridomas had helper activity, as they were able to reconstitute in vitro the synthesis of TGE virus-specific antibodies by Th cell-depleted spleen cells from immune BALB/c mice. The antibodies that they induced specifically neutralized by 103-to 104-fold the infectivity of TGE virus, ruling out the possibility of inhibition of virus replication by interferon. These hybridomas could be very useful for identifying antigenic domains in TGE virus recognized by Th cells, which cooperate with B cells in the synthesis of neutralizing antibodies. Downloaded from www.microbiologyresearch.org by IP: 54.160.113.5 On: Fri, 27 May 2016 13:26:16 660 M. J. BULLIDO AND OTHERS
Journal of Ethnopharmacology, 2001
A total of 21 extracts derived from 17 different plant species collected in Venezuelan Amazons ha... more A total of 21 extracts derived from 17 different plant species collected in Venezuelan Amazons have been tested for the following biological activities: cardiovascular activity, brine shrimp lethality, and inhibitory effects on the hydrolysis of glucose-6-phosphate in intact and disrupted microsomes. Eight extracts diminished rat blood pressure with or without changes in heart rate. The fruit extract of Swartzia leptopetala and the leaf and twig extract of Connarus lambertii resulted in death of experimental animals. The majority of extracts (17 extracts) showed significant toxicity against Artemia salina. Concerning the hydrolysis of glucose-6-phosphate, better inhibitory effects were observed in intact microsomes than in disrupted ones for all the extracts, suggesting that these extracts intervene with variable potency in glucose-6-phosphate transport through the microsomal membrane.
Journal of Ethnopharmacology, 2001
It is well known that gingivitis is a bacterially-elicited inflammation of the marginal gingiva. ... more It is well known that gingivitis is a bacterially-elicited inflammation of the marginal gingiva. A number of chemical agents have been evaluated over the years with regard to their antimicrobial effects in the oral cavity; however, all are associated with side effects that prohibit regular long-term use. Therefore, the effectiveness of a natural Mexican Sanguinaria extract (Polygonum a6iculare L.) against gingivitis, was assessed in 60 male dentistry students between the ages of 18 and 25 years. Over a period of 2 weeks, these students used the Sanguinaria extract (1 mg/ml) in oral rinse twice daily as a unique oral health measurement (no tooth-brushing was allowed). The O'Leary Plaque Index and the Lö e and Silness Gingivitis Index were recorded at baseline (day 0) in all the subjects. Also, a complete prophylaxis was performed after both indices were obtained. The antibacterial and antiinflammatory effects of the extract were evaluated on days 7, 11 and 14. The results showed that the Mexican Sanguinaria extract in oral rinse significantly decreased gingivitis from day 0 (x =1.056) to day 14 (x = 1.011) (P5 0.05). In contrast, a significant increase in dental plaque was observed from day 0 (x = 91.38) to day 14 (x = 98.69) (P5 0.05); however, the consistency of this plaque permitted its mechanical flushing easily. From this study, it is concluded that the Mexican Sanguinaria extract in oral rinse can be employed supportively in the therapy of gingivitis.
Journal of Enzyme Inhibition and Medicinal Chemistry, 2005
The in vivo and in vitro antiandrogenic activity of four aromatic esters 10a-10d, one aliphatic e... more The in vivo and in vitro antiandrogenic activity of four aromatic esters 10a-10d, one aliphatic ester 10e based on the pregna-4,16-diene-6, 20-dione structure and two aromatic 17c, 17d and two aliphatic valeroyloxy esters 17a, 17b based on the more saturated 4-pregnene-6,20-dione skeleton was examined. The biological activity of steroids 9, 10a-10e and 17a-17d, was determined using prostate glands from gonadectomized adult male golden hamsters. In the in vitro studies, the relative binding affinity of these steroids to cytoplasmic androgen receptor (AR) of hamster prostate was determined from, the corresponding IC50 values obtained from the competitive binding plots. The standards dihydrotestosterone (DHT) and cyproterone (CA) acetate used have displaced [3H]DHT from the AR with an IC50 value of 3.2 and 4.4 nM respectively. All steroidal compounds synthesized in this study showed a binding affinity for the androgen receptor, present in the cytosol from prostate hamster; compounds 10a-10c showed the highest affinities for this receptor. The in vivo experiments showed that all steroidal derivatives were subcutaneously active, since they decreased the weight of the prostate gland in gonadectomized hamsters treated with DHT, and are antagonists for the androgen receptor since they block the DHT-induced prostate weight gain. The derivatives having the more conjugated 4,16-pregnadiene-6, 20-dione system (10a-10c) exhibited a higher antiandrogenic activity than the corresponding steroids (17a-17d) based on the more saturated 4-pregnene-6,20-dione system.
Journal of Clinical Epidemiology, 1998
Objective: In the laparoscopic era choledocholithiasis diagnosis has be-Objective: To investigate... more Objective: In the laparoscopic era choledocholithiasis diagnosis has be-Objective: To investigate the association between type II diabetes and generalizated alveolar bone loss (GABL). come extremely important. The goal of this study was to develop a model for routine pre-operative screening, in order to determine the risk of choled-Design: A case-control study.
Journal of Allergy and Clinical Immunology, 2006
Development, 2008
RTK pathways establish cell fates in a wide range of developmental processes. However, how the pa... more RTK pathways establish cell fates in a wide range of developmental processes. However, how the pathway effector MAPK coordinately regulates the expression of multiple target genes is not fully understood. We have previously shown that the EGFR RTK pathway causes phosphorylation and downregulation of Groucho, a global co-repressor that is widely used by many developmentally important repressors for silencing their various targets. Here, we use specific antibodies that reveal the dynamics of Groucho phosphorylation by MAPK, and show that Groucho is phosphorylated in response to several RTK pathways during Drosophila embryogenesis. Focusing on the regulation of terminal patterning by the Torso RTK pathway, we demonstrate that attenuation of Groucho's repressor function via phosphorylation is essential for the transcriptional output of the pathway and for terminal cell specification. Importantly, Groucho is phosphorylated by an efficient mechanism that does not alter its subcellular localisation or decrease its stability; rather, modified Groucho endures long after MAPK activation has terminated. We propose that phosphorylation of Groucho provides a widespread, long-term mechanism by which RTK signals control target gene expression.
Cytogenetic and Genome Research, 2004
Rye B chromosomes (Bs) have strong parasitic effects on fertility. B carrying plants are less fer... more Rye B chromosomes (Bs) have strong parasitic effects on fertility. B carrying plants are less fertile than 0B ones, whereas the Bs have no significant effects on plant vigour. On the other hand, it has been reported that B transmission is under genetic control in such a way that H line plants transmit the Bs at high frequency, whereas the Bs in the low B transmission rate line (L) fail to pair at metaphase I and are frequently lost. In the present work we analyse variables affecting vigour and fertility considering not only the number of Bs of each plant, but also its H or L status and the B number of its maternal parent. Our results show that the Bs not only decrease female fertility of the B carrier, but the fertility of its progeny, with the exception of 0B plants coming from a 4B mother, which are the most fertile. In this way B chromosomes can be considered as a selective factor. Pollen abortion was higher in B carriers, in the progeny of B carriers and in H plants, but 4B plants coming from B carrying mothers produce less aborted pollen, indicating that a high B number is more deleterious if it is transmitted in the pollen grains. A similar result was obtained for endosperm quality estimated as grain weight, because it is negatively influenced by the Bs in 4B plants coming from a 0B mother. H plants were always less fertile than L ones, indicating that alleles increasing the loss of Bs in the L line will be probably selected as a defence of the A genome against the invasive Bs of the H line. Flower number is not affected by the Bs.
Animal Feed Science and Technology, 1999
The objective of this article is to offer some information about traditional practice regarding t... more The objective of this article is to offer some information about traditional practice regarding the use of the genus Buddleia in the Highlands of Chiapas, Mexico, with the aim of increasing its use as a potential fodder for sheep feeding in the area. Based on the indigenous Tzotzil Botanical Classification, three Buddleia groups were taxonomically identified. Group 1 includes the species Buddleia skutchii and Buddleia cordata, group 2, Buddleia americana and Buddleia crotonoides, and group 3, Buddleia parviflora and Buddleia nitida. Even though all these groups have been used as fodder, the most frequently used are the species in group 1, which are the most common species with the widest distribution patterns. Based on their chemical composition, the species of higher nutritional values were B. skutchii and B. crotonoides (crude protein (CP), 10.6% and 9.3%; neutral detergent fiber (NDF), 37.5% and 33.7%; in vitro dry matter digestibility (IVDMD), 75.9% and 58.2%; and digestible energy (DE), 3.3 and 2.5 Mcal/kg). The first one has been recommended for sheep feeding based on its high nutritional value. During an intake and digestibility trial, B. skutchii leaves substituted 50% of Kikuyo grass (Pennisetum clandestinum) without decreasing dry matter (DM) intake and digestibility. These results suggest that the systematic incorporation of B. skutchii into existing sheep production systems could 0377-8401/99/$ ± see front matter # 1999 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 7 -8 4 0 1 ( 9 9 ) 0 0 0 4 1 -3 markedly increase feed resources without higher pressure on pasture land. #