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A Esteves

Publications and source records attributed to A Esteves.

At least 19 recordsLinked to original sources
PubMed2001

Binding properties of Echinococcus granulosus fatty acid binding protein.

EgFABP1 is a developmentally regulated intracellular fatty acid binding protein characterized in the larval stage of parasitic platyhelminth Echinococcus granulosus. It is structurally related to the heart group of fatty acid binding proteins (H-FABPs). Binding properties and ligand affinity of recombinant EgFABP1 were determined by fluorescence spectroscopy using cis- and trans-parinaric acid. Two binding sites for cis- and trans-parinaric acid were found (K(d(1)) 24+/-4 nM, K(d(2)) 510+/-60 nM for cis-parinaric acid and K(d(1)) 32+/-4 nM, K(d(2)) 364+/-75 nM for trans-parinaric). A putative third site for both fatty acids is discussed. Binding preferences were determined using displacement assays. Arachidonic and oleic acids presented the highest displacement percentages for EgFABP1. The Echinococcus FABP is the unique member of the H-FABP group able to bind two long chain fatty acid molecules with high affinity. Structure-function relationships and putative roles for EgFABP1 in E. granulosus metabolism are discussed.

Amino Acid Sequence↗
PubMed2001

Follow-up study of intrahost HIV type 2 variability reveals discontinuous evolution of C2V3 sequences.

Sequence change dynamics in the highly polymorphic C2V3 region of the envelope glycoprotein gp105 coding sequence of HIV-2 was studied for two HIV-2 seropositive Guinean individuals over a 5-year period. Proviral DNA was amplified by PCR from uncultured peripheral blood mononuclear cells (PBMC), cloned, and sequenced. Amino acid sequence alignment and phylogenetic analysis showed distinct viral populations for the three collected samples (1992, 1995, and 1997) for both individuals. A discontinuous replacement of sequences suggests activation of latent viruses present in reservoirs, a process that has been documented for the HIV-1 infection but unreported so far for HIV-2. The nucleotide sequences presented in this work have been assigned accession numbers AJ400276 to AJ400319.

Amino Acid Sequence↗
PubMed2001

Extrinsic compression of the left main coronary artery by a dilated pulmonary artery: clinical, angiographic, and hemodynamic determinants.

Extrinsic compression of the left main coronary artery (LMC) by the pulmonary artery (PA) is a very unusual and poorly understood entity, usually associated with the presence of adult congenital heart disease. We identified 12 patients (age range, 6 months to 55 years) with LMC stenosis (> or = 50%) presumably secondary to compression by a dilated main PA and related to various forms of heart disease (11 congenital, 1 pulmonary hypertension). In all cases, the main PA was dilated with the main PA/aortic root diameter increased (mean, 2.0; normal value, < or = 1.0), and in all but two, PA pressures were increased (> 30 mm Hg systolic). Left coronary trunk stenosis was usually visualized in only one angiographic view (best seen in 45 degrees left anterior oblique, 30 degrees cranial projection). The LMC also appeared to be inferiorly displaced and in close contact with the left aortic sinus (mean angle between sinus and LMC was 23 degrees +/- 13 degrees, a control group was 70 degrees +/- 15 degrees ). In one patient, surgical correction of the dilated PA was associated with a reduction in LMC stenosis from 85% to < 50% and less inferior left main displacement (from 25 degrees to 50 degrees ). Patients with a dilated main PA may exhibit extrinsic LMC compression leading to significant eccentric narrowing and downward displacement of the LMC. In the presence of significant dilatation of the main PA from any etiology, functional and/or anatomic studies should be performed to exclude significant LM obstruction.

Adolescent↗
PubMed2000

Longstanding presence of HIV-2 infection in Guinea-Bissau (West Africa).

We have retrospectively studied the seroprevalence of the human immunodeficiency virus (HIV) in Guinea-Bissau in a sample of sera collected from the whole country in 1980. We tested a total of 1248 individuals and found 11 individuals who were seropositive for HIV-2 but there were no HIV-1 seropositive samples. The mean age of the HIV-2 seropositive people was significantly higher than the age of the seronegative individuals. In the different areas surveyed, the HIV-2 seroprevalence ranged from 0 to 2.5%. A central region of the country, grossly centred in the capital city of Bissau, presented the highest prevalence of HIV-2 seropositivity (>2%), which contrasts with its virtual absence from the more remote rural areas located near the borders with the neighbouring countries. The overall seroprevalence found for HIV-2 in this study is 0.9% (1.8%, when considering the adult seroprevalence only), which proves that the virus was definitely circulating in Guinea-Bissau at the beginning of the 1980s.

Adult↗
PubMed2000

Genetic variability of human immunodeficiency virus type 2 C2V3 region within and between individuals from Bissau, Guinea-Bissau, West Africa.

The V3 loop of both HIV-1 and HIV-2 is characterized by a high degree of genetic variation. To investigate the spectrum of HIV-2 variability in nature we have focused on the C2V3 region of Env and analyzed 108 viral sequences obtained from uncultured peripheral blood mononuclear cells obtained from 16 HIV-2-seropositive individuals from Bissau (Guinea-Bissau). The estimated values of genetic divergence between individuals were higher than those calculated from sequence information collected in a single individual. We have also found that the sequences surrounding the V3 loop contribute significantly to the overall genetic diversity of the C2V3 region of HIV-2 gp105, while the V3 loop itself seems to be rather conserved. Phylogenetic analysis demonstrated that all the individuals enrolled in this study were infected with HIV-2 subtype A viruses.

Adolescent↗
PubMed2000

Genetic characterization of HIV type 1 and type 2 from Bissau, Guinea-Bissau (West Africa).

Previous studies from Guinea-Bissau (West Africa) have demonstrated a unique epidemiology with respect to both HIV-1 and HIV-2 infection. In order to evaluate the prevalence and dynamics of HIV-1 and HIV-2 subtypes in Bissau, the capital city of Guinea-Bissau, a cross-sectional study was set up using serological and molecular techniques. Plasma samples from 103 individuals were screened for HIV-1 and HIV-2 antibodies by ELISA and Western-blot. Seropositive results were confirmed by PCR amplification of proviral sequences in primary peripheral blood mononuclear cells (PBMC) with env and LTR primer sets for HIV-2 and env, LTR and pol primers for HIV-1. A total of 38/103 individuals were HIV-seroreactive (four HIV-1, 15 HIV-2, 19 HIV-1/HIV-2). A total of eight out of 19 dually seropositive specimens showed double PCR amplification of HIV-1 and HIV-2 proviral sequences, accounting for 21% of the infected individuals. In the remaining 11 individuals either HIV-2 or HIV-1 sequences were detected, the majority (n=9) amplifying only HIV-2. These screening data demonstrate a high discrepancy between serology and PCR results for dually seroreactive samples, Western-blot giving an overestimation of double infection. Additionally, HIV-1 strains were subtyped by heteroduplex mobility assay (HMA) on the basis of gp120 sequences. Subtyping of HIV-2 was carried out by DNA sequencing and phylogenetic analysis of env V3 molecular clones. For both HIV-1 and HIV-2 strains circulating in Bissau, our results indicate dominance of subtype A.

Adolescent↗
PubMed1998

Modelling a 3D structure for EgDf1 from Echinococcus granulosus: putative epitopes, phosphorylation motifs and ligand.

EgDf1 is a developmentally regulated protein from the parasite Echinococcus granulosus related to a family of hydrophobic ligand binding proteins. This protein could play a crucial role during the parasite life cycle development since this organism is unable to synthetize most of their own lipids de novo. Furthermore, it has been shown that two related protein from other parasitic platyhelminths (Fh15 from Fasciola hepatica and Sm14 from Schistosoma mansoni) are able to confer protective inmunity against experimental infection in animal models. A three-dimensional structure would help establishing structure/function relationships on a knowledge based manner. 3D structures for EgDf1 protein were modelled by using myelin P2 (mP2) and intestine fatty acid binding protein (I-FABP) as templates. Molecular dynamics techniques were used to validate the models. Template mP2 yielded the best 3D structure for EgDf1. Palmitic and oleic acids were docked inside EgDf1. The present theoretical results suggest definite location in the secondary structure of the epitopic regions, consensus phosphorylation motifs and oleic acid as a good ligand candidate to EgDf1. This protein might well be involved in the process of supplying hydrophobic metabolites for membrane biosynthesis and for signaling pathways.

Amino Acid Sequence↗
PubMed1997

Remarks on the phylogeny and structure of fatty acid binding proteins from parasitic platyhelminths.

Four fatty acid binding proteins (FABPs) have been described in 4 parasitic platyhelminths: Schistosoma mansoni, Schistosoma japonicum, Fasciola hepatica and Echinococcus granulosus. FABPs form a multigenic family of cytosolic proteins widely distributed in metazoan tissues, the function of which is still poorly understood. These helminth proteins have recently received attention, since there are reports to indicate that S. mansoni and F. hepatica FABPs may be protective antigens. In addition, these proteins could play a major role in the parasites' life-cycles because platyhelminths are unable to synthesize de novo most of their lipids. We have undertaken phylogenetic and structural analyses of platyhelminth FABPs in an attempt to characterize features of biological relevance. Phylogenetically, these FABPs appear to be more closely related to those of vertebrate heart, mammary gland, muscle, retina, skin, brain and myelin, although no clear functional relationships were established between them. We describe several conserved motifs characteristic of specific groups of FABPs. Hydrophilicity, flexibility and accessibility analyses revealed several major putative epitopes for the E. granulosus FABP, EgDf1, that appear to be centred in loops of the EgDf1 3-dimensional structure modelled by molecular replacement.

Amino Acid Sequence↗
PubMed1997

Expression and immunogenicity of an Echinococcus granulosus fatty acid-binding protein in live attenuated Salmonella vaccine strains.

Fatty acid-binding proteins (FABPs) are candidate molecules for vaccines against several parasitic platyhelminths. A FABP from the cestode Echinococcus granulosus (EgDf1) was expressed in Salmonella vaccine strains as a C-terminal fusion to fragment C of tetanus toxin (TetC) by using expression vector pTECH. The fusion protein was equally expressed in several attenuated vaccine strains derived from bacteria with different genetic backgrounds and different attenuating mutations. Single-dose immunization experiments with the aroA Salmonella typhimurium strain SL3261 carrying the pTECH-EgDf1 construct were conducted with mice, using both the intravenous and the oral routes. Surprisingly, the antibody response to EgDf1 and the antigen-specific cytokine production in spleen cells were stronger in mice immunized orally. Furthermore, immune mouse sera strongly reacted with fixed sections of the worm's larval stage. Analysis of the isotype distribution of the specific anti-EgDf1 antibodies showed similar production of immunoglobulin G1 (IgG1) and IgG2a together with specific IgA antibodies. In addition, stimulation of spleen cells from mice immunized with the different constructs with either Salmonella lysate, TetC, or EgDf1 showed that, together with Th1-related cytokines (gamma interferon and interleukin 2 [IL-2]), significant levels of a Th2 cytokine (IL-5) were produced specifically, indicating a Th2 component to the response to the Salmonella carrier and to the recombinant antigens. Salmonellae expressing the TetC-rEgDfl fusion are currently under evaluation as potential vaccines against E. granulosus.

Animals↗
PubMed1994

[Percutaneous angioplasty and surgical revascularization in renovascular hypertension: experience in treatment and long-term follow up in 124 patients].

PURPOSE: To report the experience in the treatment and long-term follow-up of patients with renovascular hypertension submitted to angioplasty and/or surgical revascularization, and to compare blood pressure and renal function responses to both treatment. METHODS: One hundred and twenty-four patients diagnosed with renovascular hypertension, divided, according to the etiology, as atherosclerosis (76 patients), fibromuscular dysplasia (32) and arteritis (16), were submitted to isolated or associated treatment of renal revascularization by percutaneous transluminal angioplasty (71 patients) or surgery (84). The patients were followed-up during 2.5 +/- 1.5 years and we evaluate blood pressure response and renal function preservation. In relation to blood pressure control, the patients were considered as cured when normotensives without antihypertensives, improved when normotensives with fewer drugs than previously, and unchanged, when out of these criteria. RESULTS: From 124 patients, 20% were considered cured, 54% improved and 26% unchanged, after a mean follow-up of 2.5 +/- 1.5 years. Patients with atherosclerosis and fibromuscular dysplasia presented a higher rate of care and improvement after surgery. The blood pressure and the number of antihypertensive drugs decreased significantly during the follow-up among patients that cured or improved arterial hypertension, either after angioplasty (190 +/- 26/115 +/- 14 mmHg vs 130 +/- 34/85 +/- 7 mmHg. 2.70 vs 1.60 drugs) or after surgery (194 +/- 17/115 +/- 16 mmHg vs 143 +/- 18 mmHg vs 88 +/- 8 mmHg, 1.88 vs 1.51 drugs). It was also observed a significant decrease of serum creatinine among these patients. CONCLUSION: Renal revascularization in patients with renovascular hypertension, either by angioplasty or surgery, is beneficial to control blood pressure and to preserve renal function in the majority of patients.

Adult↗
PubMed1993

A developmentally regulated gene of Echinococcus granulosus codes for a 15.5-kilodalton polypeptide related to fatty acid binding proteins.

A stage-specific expressed gene has been isolated from a cDNA expression library of Echinococcus granulosus protoscolices. The isolated clone contains the complete coding sequence. The corresponding protein (EgDf1) has a molecular weight of 15.5 kDa and is expressed at the tegumental level in the protoscolices, being undetectable in the germinal layer of the metacestode. This protein shares an important homology with a family of low-molecular weight proteins involved in the binding of hydrophobic ligands. This family includes a protein of Schistosoma mansoni (Sm 14) that has immunoprotective activity in rodents. Histochemical and metabolic data already reported for E. granulosus suggest that EgDf1 could be a molecular marker for early events in the process of protoscolex differentiation.

Amino Acid Sequence↗
PubMed1993

[Neurological events in infective endocarditis].

PURPOSE: The study of frequency, modalities and course of neurological complications of infective endocarditis (IE), as well as the current indication and value of supplementary examinations. METHODS: Sixty-three patients with IE, 39 with native valve and 24 with valvar prosthesis, were prospectively studied; the mean age was 42 years and 45 (71.4%) were males. Two groups were formed: A) 41 patients without neurological events and B) 22 patients who presented 28 neurological events before or during hospitalization: ischemic cerebrovascular accident 20, hemorrhagic cerebrovascular accident 2, meningeal hemorrhage 2, meningitis 2, brain abscess 1 and seizure 1. All patients were submitted to neurological clinical examination; 57 computerized tomographies of the cranium, 28 arteriographies and 32 cerebrospinal fluid analysis were performed. RESULTS: The incidence of neurological events corresponded to 34.92% of IE patients, with a clear predominance (85.71%) of vascular as compared to infectious manifestations. Mortality was 2.32 times higher in group B patients (22.73% x 9.76%), albeit p = 0.256, and was not related to staphylococcal etiology. The neurological events were not related to sex, age and presence of valvar prosthesis. The presence of neurological complications was greater (p = 0.047) in patients with simultaneous infections in two valves (mitral and aortic) and also (p = 0.00884) in those with IE in prosthesis implanted for less than three months. All supplementary neurological examinations in group A were normal. CONCLUSION: 1) Occurrence of neurological events is a factor which influences the prognosis of IE; 2) supplementary neurological examinations did not reveal subclinical neurological complications; 3) neurological complications were significantly more frequent in patients with simultaneous mitral and aortic valve IE; 4) IE in prosthesis implanted for less than 3 months has a greater probability to develop a neurological picture as compared to IE in prosthesis implanted for more than 3 months.

Adolescent↗
PubMed1990

[Arterial hypertension associated with hyperlipoproteinemia].

Hypertension and serum cholesterol levels are strongly interrelated as cardiovascular risk factors. The Framingham study showed that the risk of both ischaemic heart disease and brain infarction doubles in presence of mild hypertensive status and triplicates in presence of a definitive hypertension. The systolic pressure showed to be the best predictor of both ischaemic heart disease and cerebral infarction particularly in persons aged more than 65 years. In terms of physiopathology we point out several mechanisms by which hypertension could interact with hypercholesterolemia on the arterial wall causing endothelial lesion, enhancing the penetration of arterial wall by lipoproteins, calcium accumulation on smooth subendothelial muscle and suppression of the relaxation factor produced by endothelial cells. In relation to the dietetic treatment, we must restrict more rigorously the ingestion of salt, saturated fatty acids, and total calories. In terms of anti-hypertensive drugs, we should: Avoid thiazide diuretics in case of cholesterol levels of moderate to high risk. Avoid beta blockers in patients with high levels of triglycerides, low HDL and low ratio total cholesterol/HDL. Consider to choose a calcium antagonist, a converting enzyme or an alpha blocker.

Humans↗
PubMed1988

Influence of sublingual captopril on plasma catecholamine levels during hypertensive emergencies and cold immersion.

Experimental evidence of captopril-induced inhibition of sympathetic activity, mediated by decrease in angiotensin II production, is presented. The blood pressure, plasma catecholamine, plasma renin activity, and plasma aldosterone responses to a single dose of sublingual captopril in 23 patients with hypertensive emergencies were evaluated. The major correlation found was between the captopril-induced decrease in blood pressure and the decrease in plasma norepinephrine levels (r = 0.57, p less than 0.01). In another 11 hypertensive patients with normal or high renin levels, captopril lowered by 65 percent the increase in plasma norepinephrine induced by cold immersion of the forearm. In both circumstances, plasma renin and aldosterone levels changed in accordance with the expected inhibition of angiotensin converting enzyme activity. These data suggest that, in selected circumstances in hypertensive patients, captopril exhibits a depressive influence on sympathetic activity along with the inhibition of the renin-angiotensin system.

Administration, Sublingual↗
PubMed1987

DNA-binding proteins specified by African swine fever virus.

[35S]Methionine-labeled proteins from total or cytoplasmic extracts of Vero cells infected with African swine fever virus were chromatographed on native and denatured DNA-cellulose and DNA-binding proteins were analyzed by SDS-polyacrylamide gel electrophoresis (SDS-PAGE), by DNA binding to Western blots, or by two-dimensional electrophoresis. Thirteen virus-specific DNA-binding proteins were detected by one-dimensional analysis. Major species have molecular mass 44,000 (44K), 38K, 20K, 18K, 14K, 13K, and 12K. The remaining DNA-binding proteins are proteins with molecular mass 130K, 110K, 35K, 33K, 17K, and 14.5K. When viral DNA used in the binding assay the results were very similar but the 13K protein did not bind viral DNA. Seven other minor virus-specific DNA-binding proteins could be detected by two-dimensional analysis. This technique also enabled the assignment of virus-specific proteins. Seven of the virus-specific DNA-binding proteins are structural proteins. Twelve are late proteins, the remaining being early proteins synthesized before viral DNA replication. Most of the virus-specific DNA-binding proteins bind both to double-stranded and to single-stranded DNA. The 110K, 29K, and 18K DNA-binding proteins bind only to single-stranded DNA. Two virus-specific enzymatic activities, DNA polymerase and RNA polymerase, were present in the fractions separated by DNA-cellulose chromatography. The virus-specific single-stranded DNA nuclease did not bind to DNA.

African Swine Fever Virus↗
PubMed1986

Two-dimensional analysis of African swine fever virus proteins and proteins induced in infected cells.

Two-dimensional (2D) analysis of African swine fever (ASF) virus purified by Percoll gradient centrifugation resolves 54 structural proteins, 30 in conventional IEF gels and 24 in NEPHGE gels, while only 26 structural proteins are separated by SDS-PAGE. The two main bands separated by SDS-PAGE, with mol wt 150K and 72K, correspond to single spots in 2D gels. Other bands, including major bands of 38K, 35K, 24K, 17K, and 15.5K mol wt, correspond to multiple proteins of the same molecular weight but different pI. One hundred six virus-specific proteins were resolved by 2D analysis, 59 in conventional IEF gels and 47 in NEPHGE gels. Thirty-five of the virus-specific proteins are early proteins, synthesized before DNA replication, and the remaining 71 proteins are late proteins. Early proteins belong to two groups: 11 transient early proteins are synthesized only early in infection and the other 24 are persistent early proteins, synthesized at both early and late phases. Treatment with cytosine arabinoside prevents the synthesis of late proteins and blocks the shut-off of the synthesis of transient early proteins. Eleven structural proteins are major early proteins and 28 are late proteins. The remaining 15 structural proteins migrate in 2D gels like cellular proteins. Three of these cellular proteins, with mol wt 58K, 56K, and 45K were identified by immunoblotting as alpha-tubulin, beta-tubulin, and actin, respectively.

Animals↗
PubMed1984

Protein composition of cerebrospinal fluid in the developing chick embryo.

Proteins from cerebrospinal fluid of chick embryos at 4-19 days of development were qualitative and quantitatively analyzed. The total protein concentration and the relative concentration of each protein fraction were calculated for each day. The main proteins found along development were immunoglobulin G, transferrin, alpha-fetoprotein, serum albumin, ovalbumin, prealbumin, and an unidentified component. alpha-Fetoprotein was found to be the major protein at 4-16 days, and serum albumin at 17-19 days of development. The unidentified fraction was present from 4 to 11 days; at day 5 it represented 28% of the total cerebrospinal fluid protein concentration.

Albumins↗