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Biomedical subjects

E Iglesias

Publications and source records attributed to E Iglesias.

At least 19 recordsLinked to original sources
PubMed2004

Development of a nasal vaccine for chronic hepatitis B infection that uses the ability of hepatitis B core antigen to stimulate a strong Th1 response against hepatitis B surface antigen.

There are estimated to be 350 million chronic carriers of hepatitis B infection worldwide. Patients with chronic hepatitis B are at risk of liver cirrhosis with associated mortality because of hepatocellular carcinoma and other complications. An important goal, therefore, is the development of an effective therapeutic vaccine against chronic hepatitis B virus (HBV). A major barrier to the development of such a vaccine is the impaired immune response to HBV antigens observed in the T cells of affected patients. One strategy to overcome these barriers is to activate mucosal T cells through the use of nasal vaccination because this may overcome the systemic immune downregulation that results from HBV infection. In addition, it may be beneficial to present additional HBV epitopes beyond those contained in the traditional hepatitis B surface antigen (HbsAg) vaccine, for example, by using the hepatitis B core antigen (HBcAg). This is advantageous because HBcAg has a unique ability to act as a potent Th1 adjuvant to HbsAg, while also serving as an immunogenic target. In this study we describe the effect of coadministration of HBsAg and HBcAg as part of a strategy to develop a more potent and effective HBV therapeutic vaccine.

Administration, Intranasal↗
PubMed2003

A systematic comparison of methods to measure HIV-1 specific CD8 T cells.

Several methods are now available to evaluate the frequencies of virus-specific CD8 T cells but require a systematic comparison to help at choosing the best strategy for evaluation. First, we compared the ELISpot-IFNgamma assay, intracellular IFNgamma staining and HLA class I tetramer-binding assay to quantify the HIV-specific CD8 T cells. Second, we determined the frequency of recognition of HIV antigens and evaluated whether the mode of antigen presentation might influence the results: We compared HIV antigen presentation in the same ELISpot-IFNgamma assays by using recombinant vaccinia viruses (rVVs) encoding for HIV-LAI Gag, Pol, Env, Nef, Tat and Vif proteins, or a panel of 49 synthetic 8-11 amino acid length peptides tested either individually or pooled. Third, we compared the antigens recognized by memory CTL analysis using chromium release assay (CRA) on CTL lines and by effector CD8 cell analysis using ELISpot assay. Our results show that: (1) Flow cytometry and ELISpot assay measuring IFNgamma production give the same frequency of HIV-specific CD8 T cells; (2) tetramer-binding assay detects more HIV-specific CD8 T cells than other methods; (3) pools of optimal peptides and sum frequencies of individual optimal peptides give similar results in ELISpot assay; (4) ELISpot assays using peptides are more sensitive than those using rVV; and (5) CRA and ELISpot assay when using rVV provide a comparable profile of HIV antigen recognition by memory CTLs (CRA) and effector CTLs (ELISpot) in two thirds cases. These results have important implications for the choice of immunological methods to evaluate CD8 T cells responses to vaccines.

AIDS Vaccines↗
PubMed2001

A phase I clinical trial of a multi-epitope polypeptide TAB9 combined with Montanide ISA 720 adjuvant in non-HIV-1 infected human volunteers.

A phase I clinical trial was performed to examine the safety and immunogenicity of a multi-epitope polypeptide comprising the central 15 amino acids of the V3 loop from six HIV-1 isolates. This protein called TAB9 was emulsified in Montanide ISA720 (Seppic, Paris) and administered intramuscularly at doses of 0, 0.2 and 1 mg to 24 healthy, HIV-1 seronegative adult males. Three immunisations were given at months 0, 1 and 6 in a randomised, double blind, placebo controlled clinical trial. The placebo was generally well tolerated. However, severe local reactions were observed in TAB9 vaccinated subjects after the second and third inoculations. Seven out of eight volunteers from the lower dose group showed moderate or severe local inflammation, while four out of eight subjects from the higher dose group developed granulomas and sterile abscesses. In general, the reactogenicity depended on the number of inoculations given and the dose of TAB9. Both doses were immunogenic, all immunised volunteers seroconverted and antibodies were broadly reactive against the V3 peptides included in the protein. All vaccine's sera reacted against gp120 in Western blot and 50% of them also neutralised at least one out of five laboratory isolates tested. No differences between doses were found. Anti TAB9 lymphoproliferative responses were observed, being more intense in the high dose group. Due to the strong local reactions that were found in this study, a change in the formulation will be required for further trials with this vaccine candidate in humans.

AIDS Vaccines↗
PubMed2001

Isolates from four different HIV type 1 clades circulating in Cuba identified by DNA sequence of the C2-V3 region.

According to the epidemiology of human immunodeficiency virus infection in Cuba, the main sources of infection have been persons coming from foreign countries, mainly from Africa, and individuals who have had sexual contacts with foreigners in Cuba. However, the first Cuban HIV-1 isolates sequenced have been all classified as subtype B. In this note we report the sequence of the gp120 C2/V3 region from 11 HIV-1 isolates from Cuban patients. DNA was isolated either directly from blood PBMC or from primary isolates, PCR amplified and sequenced. Six isolates were classified as subtype B and three of them had the atypical sequences GRGR, GWGR, and TPGR on the tip of the V3 loop. Besides, two other sequences were classified as subtype A, two as subtype H, and one as subtype C. These results confirm that although subtype B seems to be predominant, HIV-1 isolates from various subtypes do circulate in Cuba.

Amino Acid Sequence↗
PubMed2001

Study of different coupling agents in the conjugation of a V3-based synthetic MAP to carrier proteins.

The conjugation of synthetic peptides to carrier proteins is a widely used method for immunological studies. Different coupling agents have been described to form the conjugate with carrier proteins. In this paper, we demonstrate that the antibody response toward V3-based synthetic MAPs derived from HIV-1, JY1 isolate, conjugated to two different carrier proteins using either m-maleimidobenzoyl-N-hydroxysuccinimide ester (MBS) or beta-maleimidopropionic acid N-hydroxysuccinimide ester (MPS), or succinic anhydride (SA) show different behaviors. An excellent anti-JY1 response without a strong response to the coupling agent is observed in the case of succinic anhydride spacer. In contrast, MBS produces total abrogation of the antibody response with a high response toward the coupling agent.

Animals↗
PubMed2000

Ester hydrolysis and enol nitrosation reactions of ethyl cyclohexanone-2-carboxylate inhibited by beta-cyclodextrin

Both the ester hydrolysis and the nitrosation reactions of the enol tautomer of ethyl cyclohexanone-2-carboxylate (ECHC) are investigated in the absence and presence of beta-cyclodextrin (beta-CD). The ester hydrolysis reaction is studied in dilute H2O and D2O solutions of hydrochloric acid and in aqueous buffered solutions of carboxylic acids (acetic acid and its chloro derivatives). The pseudo-first-order rate constant increases with both the [H+] and the total buffer concentration, indicating that the hydrolysis is subject to acid and general base catalysis. Substantial solvent isotope effects in the normal direction (kH/kD > 1) for the acid-catalyzed hydrolysis was observed. Addition of beta-CD strongly slows the hydrolysis reaction. The variation of the observed rate constant (k(o)) with [beta-CD] exhibits saturation behavior, consistent with 1:1 binding between the enol of ECHC and beta-CD. The binding is quite strong, and bound ECHC-enol is unreactive. The nitrosation reaction of ECHC in aqueous acid medium, using sodium nitrite in great excess over the concentration of ECHC, yields perfect first-order kinetics, indicating that the slow step is the nitrosation of the enol tautomer. This finding suggests that a great percentage of the total ECHC concentration must exist in the enol form. The nitrosation reaction is of first order in [nitrite] and is catalyzed by the presence of Cl-, Br-, or SCN- ions, which indicates that the attack of the nitrosating agent is the slow step. The nitrosation reaction is also strongly inhibited by the presence of beta-CD because of the formation of unreactive inclusion complexes between the host, beta-CD, and the guest, the enol of ECHC. In alkaline medium, the formation of the enolate ion is observed, which absorbs at higher wavelengths (lambda(max) = 256 nm in acid medium shifts to lambda(max) = 288 nm in alkaline medium). This anion also undergoes ester hydrolysis spontaneously, but shows neither specific basic catalysis nor appreciable effect by the presence of beta-CD. From kinetic and spectroscopic measurements the pKa of the enol of ECHC has been determined as 12.35.

Journal Article↗
PubMed2000

Quantitation of nifedipine in human plasma by on-line solid-phase extraction and high-performance liquid chromatography.

An analytical methodology for nifedipine quantitation in plasma by on-line solid-phase extraction (SPE) and high-performance liquid chromatography (HPLC) is described. The SPE cartridges contain C2 and the analytes nifedipine and nitrendipine (internal standard) are separated on a C18 column with a mobile phase consisting of acetonitrile-13 mM phosphate buffer pH 7 (65:35, v/v) followed by UV detection at 338 nm. Validation of the method demonstrated good recoveries (>90%), sensitivity (limit of quantification, 2 ng/ml), based on a 500 microl sample volume, accuracy and precision (<5.5% in concentrations greater than the limit of quantitation). This methodology has been used for bioequivalence studies.

Calcium Channel Blockers↗
PubMed2000

Immunogenicity comparison of a multi-antigenic peptide bearing V3 sequences of the human immunodeficiency virus type 1 with TAB9 protein in mice.

The multiple antigenic peptide system (MAP) has been proposed as a novel and valuable approach for eliciting antibodies for peptides and developing synthetic vaccines. Multi-epitope polypeptides (MEP) have also been developed as an alternative to the recombinant approach for vaccines. The V3 loop from the HIV type 1 (HIV-1) external glycoprotein (gp120) contains the principal neutralization domain (PND). Antibodies against this region neutralize HIV-1 in vitro and in vivo. In this work, a novel presentation of di-epitope MAP was synthesized. A monomeric MAP carrying two identical JY1 V3 sequences as B-cell epitopes and the 830-843 region of tetanus toxoid as a T-helper cell epitope was synthesized. This basic structure was covalently linked to produce a four-JY1-branched homodimer (JY1-MAP4). Additionally, six different monomeric MAPs, bearing four copies of V3 from isolates LR150, JY1, RF, MN, BRVA and IIIB, were synthesized. These monomers were conveniently linked among themselves to produce homodimeric and heterodimeric MAPs of eight V3 branches (V3-MAP8). JY1-MAP8 elicited higher antibody titers in Balb/c mice than JY1-MAP4. The immunogenicity of two different, hexavalent V3-MAP8 mixtures and the MEP TAB9, which tandems the same six V3 sequences in a single molecule, were compared. The antibody response against the mixtures of the heterodimeric MAP showed a wider recognition pattern of the V3 region, while the homodimeric cocktail showed an intermediate pattern. Antibodies elicited by TAB9 recognized only the JY1, LR150 peptides. These results emphasize the influence of V3 epitope presentation upon the characteristics of the antibody response generated.

Amino Acids↗
PubMed2000

[Unusual cause of severe alveolar hypoventilation].

Mesenteric panniculitis is a rare disease of the adipose tissue of mesentery. Ascites is an unusual presentation. We report a case of panniculitis whose initial presentation was an obesity-hypoventilation syndrome with pulmonary hypertension. Respiratory disorders were related to abundant ascites. Panniculitis cure and ascites disappearance allowed return to normal pulmonary function and pulmonary artery pressure.

Aged↗
PubMed1999

Characterisation of the lpdA gene from Neisseria meningitidis by polymerase chain reaction, restriction fragment length polymorphism and sequencing.

P64k protein from Neisseria meningitidis is well recognised in sera from individuals convalescent from meningococcal disease or vaccinated with the Cuban antimeningococcal vaccine VA-MENGOC-BC. The presence of the protein in more than 80 meningococcal strains has also been verified. It is immunogenic in animal models and the antibodies elicited show bactericidal activity against meningococci. To further investigate at the molecular level whether lpdA, the gene coding for P64k protein, is conserved among different N. meningitidis strains, a total of 20 strains isolated from different geographic areas were differentiated on the basis of restriction fragment length polymorphism (RFLP) patterns after polymerase chain reaction (PCR) amplification of the lpdA gene and restriction endonuclease digestion with HpaII. Although a total of five different PCR-RFLP patterns were present, nucleotide sequence determination showed that identity levels were as high as 93-99% among the N. meningitidis strains analysed.

Amino Acid Sequence↗
PubMed1999

Nandrolone decanoate is a good alternative for the treatment of anemia in elderly male patients on hemodialysis.

OBJECTIVE: To assess the efficiency of nandrolone decanoate (ND) in the control of anemia in elderly male patients on hemodialysis (HD), and to determine its influence on nutritional parameters. DESIGN: A prospective 6-month study with randomization of patients on recombinant human erythropoietin (rHuEPO) therapy into two groups. Group A: rHuEPO was stopped before starting treatment with ND. Group E: rHuEPO was continued. SETTING: Renal unit, tertiary-care center. PATIENTS: 14 male patients in Group A and 19 patients, 12 males and 7 females, in Group E. INTERVENTIONS: In Group A rHuEPO was stopped and ND 200 mg/I.M. weekly was given over six months. RESULTS: The increase in hemoglobin and hematocrit levels was progressive with ND, and significant differences (p < 0.003) were evident after six months (9.6 +/- 1.0 vs 11.0 +/- 1.4 and 28.9 +/- 4.7 vs 33.0 +/- 4.7, respectively), which remained unmodified in Group E. Group A showed a significant increase in serum creatinine, total protein, transferrin and anthropometric parameters. These parameters remained stable and even presented a tendency to decrease in Group E. There was a significant rise in the concentration of triglycerides and a significant decrease in both HDL-cholesterol and apolipoprotein A-1 in Group A. However, lipoprotein (a) decreased significantly. No significant changes were detected in Group E. CONCLUSIONS: The use of ND would allow us an acceptable treatment of anemia as well as a better nutritional condition in elderly male patients on dialysis.

Aged↗