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E Martinez

Publications and source records attributed to E Martinez.

At least 91 records · Page 5Linked to original sources
PubMed1998

Morphometrics of domestic Panstrongylus rufotuberculatus in Bolivia.

The trend to domesticity in Triatominae may represent a transitionary phase, towards increasing vectorial importance in the transmission of Chagas disease to humans, and requires sustained entomological surveillance. Although generally considered a sylvatic species, Panstrongylus rufotuberculatus has been recently captured inside human dwellings in the provinces of Nor Yungas and Muñecas in the Department of La Paz, Bolivia, providing evidence of this species' ability to colonise domestic habitats. The results of previous research on domestic and sylvatic specimens of other species of Triatominae indicate that morphometrics could be used to monitor this adaptive process. The most likely cause of differences seen in the size and shape of bugs from domestic colonies of P. rufotuberculatus from two neighbouring villages in Bolivia is probably genetic drift rather than environmental influences. Comparison with allopatric sylvatic specimens, including the holotype of P. rufatuberculatus, showed a general reduction in size from sylvatic to domestic specimens.

Animals↗
PubMed1998

Fever of unknown origin in the setting of HIV infection: guidelines for a rational approach.

Fever of unknown origin constitutes a common problem in HIV-infected patients that, paradoxically, has received little attention in the literature. A review on this topic collecting data from different series showed that mycobacterial infections, particularly tuberculosis, were responsible for the fever in more than half of the patients. However, the relative frequencies of the different etiologies may vary substantially depending on the local prevalences of certain infections. With the notable exception of tuberculosis, which may develop at any stage of HIV infection, fever of unknown origin usually presents in patients with advanced disease when the CD4 cell count is below 100/microliter. In this overview we stress, from a practical point of view, some points to be considered in the evaluation of the HIV-infected patient who presents with fever of unknown origin, as well as the usefulness and yield of several diagnostic procedures.

AIDS-Related Opportunistic Infections↗
PubMed1998

Novel cofactors and TFIIA mediate functional core promoter selectivity by the human TAFII150-containing TFIID complex.

TATA-binding protein-associated factors (TAFIIs) within TFIID control differential gene transcription through interactions with both activators and core promoter elements. In particular, TAFII150 contributes to initiator-dependent transcription through an unknown mechanism. Here, we address whether TAFIIs within TFIID are sufficient, in conjunction with highly purified general transcription factors (GTFs), for differential core promoter-dependent transcription by RNA polymerase II and whether additional cofactors are required. We identify the human homologue of Drosophila TAFII150 through cognate cDNA cloning and show that it is a tightly associated component of human TFIID. More importantly, we demonstrate that the human TAFII150-containing TFIID complex is not sufficient, in the context of all purified GTFs and RNA polymerase II, to mediate transcription synergism between TATA and initiator elements and initiator-directed transcription from a TAFII-dependent TATA-less promoter. Therefore, TAFII-promoter interactions are not sufficient for the productive core promoter-selective functions of TFIID. Consistent with this finding, we have partially purified novel cofactor activities (TICs) that potentiate the TAFII-mediated synergism between TATA and initiator elements (TIC-1) and TAFII-dependent transcription from TATA-less promoters (TIC-2 and -3). Furthermore, we demonstrate an essential function for TFIIA in TIC- and TAFII-dependent basal transcription from a TATA-less promoter. Our results reveal a parallel between the basal transcription activity of TAFIIs through core promoter elements and TAFII-dependent activator function.

ARNTL Transcription Factors↗
PubMed1998

Effect of high-frequency oral airway and chest wall oscillation and conventional chest physical therapy on expectoration in patients with stable cystic fibrosis.

STUDY OBJECTIVE: To compare the effect of high-frequency oral airway oscillation, high-frequency chest wall oscillation, and conventional chest physical therapy (CPT) on weight of expectorated sputum, pulmonary function, and oxygen saturation in outpatients with stable cystic fibrosis (CF). DESIGN: Prospective randomized trial. SETTING: Pediatric pulmonary division of a tertiary care center. PATIENTS: Fourteen outpatients with stable CF recruited from the CF center. INTERVENTIONS: Two modes of oral airway oscillation (1: frequency 8 Hz; inspiratory to expiratory [I:E] ratio 9:1; 2: frequency 14 Hz; I:E ratio 8:1), two modes of chest wall oscillation (1: frequency 3 Hz; I:E ratio 4:1; 2: frequency 16 Hz; I:E ratio 1:1, alternating with frequency 1.5 Hz, I:E ratio 6:1), and CPT (clapping, vibration, postural drainage, and encouraged coughing) were applied during the first 20 min of 4 consecutive hours. MEASUREMENTS AND RESULTS: Sputum was collected on an hourly basis for a total of 6 consecutive hours. During the first and the last hour, patients collected sputum without having any treatment and underwent pulmonary function tests (PFTs). Oxygen saturation was measured at 30-min intervals during hours 1 to 6. For the first 20 min of the second to the fifth hour, patients received one of the treatments. To assess the effect of the intervention, the weight of expectorated sputum during hours 2 to 6 was averaged and expressed as percentage of the weight expectorated during the first hour (baseline). For the five treatment modalities, mean sputum dry and wet weights ranged between 122% and 185% of baseline. There was no statistically significant difference among the treatment modalities. As measured by sputum wet weight, all oscillatory devices tended to be less effective than CPT (p=0.15). As measured by dry weight, oral airway oscillation at 8 Hz with an I:E ratio of 9:1 and CPT tended to be more effective than the other treatment modalities (p=0.57). None of the treatment modalities had an effect on PFTs and oxygen saturation and all were well tolerated. CONCLUSION: In outpatients with stable CF, high-frequency oscillation applied via the airway opening or via the chest wall and CPT have comparable augmenting effects on expectorated sputum weight without changing PFTs or oxygen saturation. In contrast to CPT, high-frequency oral airway and chest wall oscillations are self-administered, thereby containing health-care expenses.

Adolescent↗
PubMed1998

Associated EMG responses to voluntary hand movement in probable Alzheimer's disease.

The goal of this work is to dilucidate the mechanism that yields the associated EMG responses in patients with probable Alzheimer's disease. Seventeen subjects fulfilling this criteria and ten normal subjects as a control group were selected. They were asked to perform an oddball task in which they had to discriminate between two kinds of stimuli and produce a response to one of them. Results show that reaction times in controls and in patients when there is no associated EMG are equal in latency. When the associated EMG response occurs in the pathological group reaction time is significantly increased. Furthermore, the associated EMG response is delayed in 55 milliseconds when compared to the voluntary movement. Although these results may reflect some controversy, we interpret this finding as a contralateral inhibitory deficit associated to the corpus callosum abnormalities that occur in the evolving course of Alzheimer's disease.

Aged↗
PubMed1998

Elevated Amniotic Fluid Interleukin-6 as a Predictor of Neonatal Periventricular Leukomalacia and Intraventricular Hemorrhage.

> Objective: To investigate the relationship between amniotic fluid interleukin-6 levels and the development of periventricular leukomalacia and intraventricular hemorrhage in the preterm neonate and to compare the value of amniotic fluid interleukin-6 with amniotic fluid culture and histologic chorioamnionitis in the prediction of periventricular leukomalacia and intraventricular hemorrhage. Methods: 119 women, between 20 and 34 weeks gestation, in preterm labor with intact membranes, underwent transabdominal amniocentesis. Amniotic fluid was cultured for aerobic and anaerobic bacteria, Ureaplasma urealyticum and Mycoplasma hominis. Amniotic fluid interleukin-6 levels were determined by enzyme-linked immunosorbent assay. The placentas were examined for histopathologic evidence of inflammation. Where the birth weight was <2,000 g, transfontanelle cranial sonography was performed on the 3rd and 7th days of life for diagnosis of periventricular leukomalacia and intraventricular hemorrhage. Student's t test, the Mann-Whitney U test, likelihood ratio chi2, logistic regression, and receiver-operator characteristic curve were used for analysis. Results: 33 women were excluded from the analysis because they delivered at other institutions. The neonates of 33 women did not have sonography because they weighed >2,000 g at birth. Two neonates died before sonography was performed; four neonates who weighed <2,000 g at birth did not have sonography. In the definitive study group of 47 women, those with neonates who developed periventricular leukomalacia and intraventricular hemorrhage (n = 14) had higher median amniotic fluid interleukin-6 levels (42,795 pg/ml versus 8,020 pg/ml; P = 0.009), more positive amniotic fluid cultures (64% vesus 21%; P < 0.003), and a shorter median amniocentesis-to-delivery interval (16 h versus 24 h; P = 0.045) than women (n = 33) who delivered neonates without periventricular leukomalacia or intraventricular hemorrhage. The groups did not differ in gestational age at admission (P = 0.15), birth weight (P = 0.09), or histologic chorioamnionitis (P = 0.37). An amniotic fluid interleukin-6 level >/=20,000 pg/ml had a sensitivity of 71% and a specificity of 70% compared with a sensitivity of 69% and specificity of 79% for amniotic fluid culture, and a sensitivity of 71% and specificity of 42% for histologic chorioamnionitis in the prediction of periventricular leukomalacia and intraventricular hemorrhage. Women with amniotic fluid interleukin-6 levels >/=20,000 pg/ml (n = 20) had more neonates with periventricular leukomalacia or intraventricular hemorrhage than women with amniotic fluid interleukin-6 levels <20,000 pg/ml (n = 27) (50% versus 15%; P = 0.009). They also were of lower birth weight (P = 0.02), had more neonatal morbidity (P = 0.01), had more positive amniotic fluid cultures (P = 0.01), and more histologic chorioamnionitis (P = 0.02). Logistic regression analysis demonstrated that amniotic fluid interleukin-6 was an independent risk factor for the development of periventricular leukomalacia and intraventricular hemorrhage (odds ratio, 5.81; 95% confidence interval, 1.02-33.16; P = 0.05) after controlling for gestational age, birth weight, histologic chorioamnionitis, and amniotic fluid culture (odds ratio, 7.94; 95% confidence interval 1.22-51.77; P = 0.03). Conclusions: In women in preterm labor with intact membranes amniotic fluid interleukin-6 is useful in predicting neonatal periventricular leukomalacia and intraventricular hemorrhage.

Journal Article↗
PubMed1997

Cloning of an inr- and E-box-binding protein, TFII-I, that interacts physically and functionally with USF1.

The transcription factor TFII-I has been shown to bind independently to two distinct promoter elements, a pyrimidine-rich initiator (Inr) and a recognition site (E-box) for upstream stimulatory factor 1 (USF1), and to stimulate USF1 binding to both of these sites. Here we describe the isolation of a cDNA encoding TFII-I and demonstrate that the corresponding 120 kDa polypeptide, when expressed ectopically, is capable of binding to both Inr and E-box elements. The primary structure of TFII-I reveals novel features that include six directly repeated 90 residue motifs that each possess a potential helix-loop/span-helix homology. These unique structural features suggest that TFII-I may have the capacity for multiple protein-protein and, potentially, multiple protein-DNA interactions. Consistent with this hypothesis and with previous in vitro studies, we further demonstrate that ectopic TFII-I and USF1 can act synergistically, and in some cases independently, to activate transcription in vivo through both Inr and the E-box elements of the adenovirus major late promoter. We also describe domains of USF1 that are necessary for its independent and synergistic activation functions.

Adenoviridae↗
PubMed1997

Detection and isolation of RNA-binding proteins by RNA-ligand screening of a cDNA expression library.

A screening assay for the detection of RNA-binding proteins was developed. It allows the rapid isolation of cDNA clones coding for proteins with sequence-specific binding affinity to a target RNA. For developing the screening protocol, constituents of the human U1 snRNP were utilized as model system. The RNA partner consisted of the U1-RNA stem-loop II and the corresponding protein consisted of the 102 amino acid N-terminal recognition motif of the U1A protein, which was fused to beta-galactosidase and expressed by the recombinant lambda phage LU1A. Following binding of the fusion protein to nitrocellulose membranes, hybridization with a 32P-labeled U1-RNA ligand was carried out to detect specific RNA-protein interaction. Parameters influencing the specificity and the detection limit of binding were systematically investigated with the aid of the model system. Processing the nitrocellulose membranes in the presence of transition metals greatly increased the signal:background ratio. A simple screening protocol involving a single-buffer system was developed. Specific RNA-protein interaction could be detected in the presence of a large excess of recombinant phages from a cDNA library. Only moderate binding affinities (Kd = 10(-8) M) were required. The suitability of the RNA-ligand screening protocol was demonstrated by the identification of new viroid-RNA binding proteins from tomato.

Bacteriophage lambda↗
PubMed1997

Folding of the presequence of yeast pAPI into an amphipathic helix determines transport of the protein from the cytosol to the vacuole.

To investigate the role of the 17 residues long presequence (p17) in the transport of the precursor of yeast API (pAPI) from the cytosol to the vacuole we have studied the effects of point mutations upon its conformation and on the process of transport. 1H NMR analysis of p17 indicates that in aqueous solution 26% of the molecules have the 4-12 segment folded into an helix. The hydrophobic environment provided by SDS micelles promotes the folding of 54% of the p17 molecules into a 5-16 amphipathic alpha-helix. Both Schiffer-Edmunson helical wheel analysis of segment 4-12 and residue hydrophobic moments calculated considering all possible side-chain orientations between 80 and 120 degrees, indicate the amphipathic character of the helixes assembled in water and detergent. Charge interactions between the dipole pairs N-Glu2Glu3 and C-Lys12Lys13 are essential for helix stability and condition pAPI transport. Substitution of either Pro2Pro3 or Lys2Lys3 for Glu2Glu3, results in moderate destabilization of the helix, decreases protein targeting to the vacuolar membrane and partly inhibits translocation of the protein to the vacuolar lumen. Replacement of either Pro12Pro13 or Glu12Glu13 for Lys12Lys13, causes a major disruption of the helix, decreases protein targeting and blocks completely the translocation of the protein to the vacuolar lumen. Replacement of Gly7 for Ile7, a substitution which is known to destabilize alpha-helixes in peptides and proteins as a result of the peptide bond to the solvent at Gly residues, produces similar effects as the substitutions for the K12K13 pair. The effects of Gly7 on helix stability and protein transport are partly reversed by introduction of Asp residues at positions 2 and 3 and Ala at position 4. Replacements such as Arg2 for Glu2, or Arg6 for Glu6, which change the net and local charges of the presequence without altering its conformation, have no effect on the protein transport. These results provide direct evidence of the involvement of the presequence in the transport of pAPI from the cytosol to the vacuole. They show that folding of the pAPI presequence is conditioned by the physical/chemical properties of the environment and is critical for targeting the protein to the vacuolar membrane and for its translocation to the vacuolar lumen.

Algorithms↗
PubMed1997

Specific interactions and potential functions of human TAFII100.

Human transcription initiation factor TFIID contains the TATA-binding protein (TBP) and several TBP-associated factors (TAFs). To investigate the structural organization and function of TFIID, we have cloned and expressed a DNA encoding the third largest human TFIID subunit, hTAFII100. Immunoprecipitation studies demonstrate that hTAFII100 is an integral subunit that is associated with all transcriptionally-competent forms of TFIID. They further suggest that at least part of the N-terminal region lies on the surface of TFIID, while a C-terminal region containing conserved WD-40 repeats appears inaccessible. Both in vivo and in vitro assays indicate that hTAFII100 interacts strongly with the histone H4-related hTAFII80 and the histone H3-related hTAFII31, as well as a stable complex comprised of both hTAFII80 and hTAFII31. Apparently weaker interactions of hTAFII100 with TBP, hTAFII250, hTAFII28, and hTAFII20, but not hTAFII55, also have been observed. These results suggest a role for hTAFII100 in stabilizing interactions of TAFs, especially the histone-like TAFs, in TFIID. In addition, functional studies show that anti-hTAFII100 antibodies selectively inhibit basal transcription from a TATA-less initiator-containing promoter, relative to a TATA-containing promoter, suggesting a possible core promoter-specific function for hTAFII100.

Amino Acid Sequence↗
PubMed1997

The Nuclear Receptor Resource Project.

We have expanded the original Glucocorticoid Receptor Resource (GRR) database to include several individual resources as part of a larger project called the Nuclear Receptor Resource (NRR). In addition to the GRR, the NRR currently features the Thyroid Hormone Receptor Resource, the Androgen Receptor Resource, the Mineralocorticoid Receptor Resource, the Vitamin D Receptor Resource, and the Steroid Receptor Associated Proteins Resource. The goal of the NRR project is to provide a comprehensive resource for information on the nuclear receptor superfamily, and to provide a forum for the dissemination and discussion of both published and unpublished material on these proteins. Although the individual resources are managed from different servers, all the files are integrated and can be accessed through the project's Home Page, housed at http://nrr. georgetown.edu/nrr.html. In the near future, we hope to expand the project to contain information on other nuclear receptors and to better our electronic publication system. To accomplish this, we encourage the involvement of nuclear receptor investigators in the NRR.

Amino Acid Sequence↗
PubMed1997

Bronchiolitis obliterans in a patient with HIV infection.

Bronchiolitis obliterans, with or without organizing pneumonia, represents an uncommon response of the lung to several injuries, that results in characteristic histopathologic changes in the small airways. The present case report describes a patient with HIV infection who developed bronchiolitis obliterans, and reviews the previously reported cases of this condition in HIV-infected patients.

Adult↗
PubMed1997

The effects of a triterpene fraction isolated from Crataegus monogyna Jacq. on different acute inflammation models in rats and mice. Leucocyte migration and phospholipase A2 inhibition.

The plant Crataegus monogyna has action against cardiac insufficiency, angina and arrhythmia. The anti-inflammatory properties of the cycloartenol fraction from this plant have been investigated. Chromatographic fractionation of the hexane extract of Crataegus monogyna Jacq. (Rosaceae) furnished a triterpene fraction containing cycloartenol as the main component (80.87%). The anti-inflammatory activity of the fraction was tested against hind-paw oedema induced by carrageenan in rats. At the highest oral dose (40 mg kg-1) inhibition was 61.5 and 52.5% at 3 and 5 h respectively. In the mouse carrageenan peritonitis test, the triterpene fraction given orally inhibited peritoneal leucocyte infiltration (41.9, 64.7 and 89.4% at 10, 20 and 40 mg kg-1, respectively). The fraction also showed weak inhibition of phospholipase A2 (PLA2) in-vitro. These results suggest that the fraction containing cycloartenol as the main component exerts an important anti-inflammatory action in-vivo by reducing the oedema.

Animals↗
PubMed1997

[Assessment of left internal thoracic artery anastomosis with left anterior descending coronary artery by Doppler echocardiography].

PURPOSE: To study the value of Doppler echocardiography as a tool for the evaluation of left internal thoracic artery graft (LITAG) patency in patients who underwent coronary revascularization using minimally invasive bypass surgery without extracorporeal circulation. METHODS: The first 12 consecutive patients were studied after coronary artery bypass surgery using a 5 MHz Doppler transducer. Doppler signals for the systolic and diastolic flow velocities were preferably obtained in the second intercostal space. All patients underwent coronary angiography while hospitalized. RESULTS: The exam was feasible in 93% of patients. Doppler flow pattern was predominantly diastolic (pattern A) in patients with patent anastomoses (6/7). In patients with occluded anastomoses (4/4) Doppler flow pattern was predominantly systolic (pattern B) (p = 0.003). CONCLUSION: Internal thoracic artery flow pattern as measured by Doppler echocardiography after minimally invasive coronary artery bypass graft surgery is an accurate method for identifying LITAG patency.

Adult↗
PubMed1997

Fever of unknown origin in the HIV-infected patient: new scenario for an old problem.

Many conditions may present as fever of unknown origin in the HIV-infected patient, and their relative frequency is influenced by multiple factors. The history and physical examination may provide some useful clues for the diagnosis. Haematological, biochemical, and conventional radiological tests are rarely diagnostic; even serological and/or microbiological tests have some limitations in these patients. The geographical setting and the local prevalence of diseases are of the utmost importance. Infections that have a world-wide distribution, such as tuberculosis, should be intensively searched for, particularly in areas of high prevalence. The measurement of the CD4+ cell count is essential, as there is a strong association between this count and certain opportunistic diseases that may manifest as fever of unknown origin. Imaging procedures, such as CT and radionuclide scans, are useful for the location of inflammatory and neoplastic lesions. Liver and bone marrow biopsies are helpful in certain subsets of patients and the efficacy of empirical treatments has been clearly documented in certain infections. Some HIV-infected patients with fever of unknown origin remain undiagnosed after a thorough investigation; these individuals should be managed conservatively. Finally, symptomatic treatment is the best option for terminally ill patients in whom benefit from a detailed investigation of the cause of fever is not expected.

AIDS-Related Opportunistic Infections↗
PubMed1997

Discrepancy between inotropic response and cyclic AMP production induced by isoprenaline and forskolin in rat ventricle strips.

The effects of isoprenaline and forskolin were studied on contractile response and cyclic AMP levels in the right ventricle strips of the rat heart. Isoprenaline, in concentrations ranging from 10 nM to 1 microM, significantly increased, in a concentration-dependent manner, the contractile force in this preparation. Forskolin (1-10 microM), which directly stimulates adenylate cyclase, also produced a concentration-dependent increase in cardiac contractility. The mean EC50 (microM) for the contractile action of isoprenaline was 0.08 +/- 0.014 and that of forskolin 7.3 +/- 1.1 being about 70 times less potent than isoprenaline. However, isoprenaline (0.1 microM) and forskolin (8 microM), which produced about the same inotropic response, increased tissue cyclic AMP levels by about two and five fold respectively, when compared to the basal value. These figures further indicate that while the intracellular levels of cyclic AMP in rat ventricular myocardium may be an important determinant of positive inotropism, the connection between the two parameters is more complex than the simple ratio between the tension generated and the amount of cyclic AMP found inside the cells.

Adrenergic beta-Agonists↗