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Biomedical subjects

M Díaz

Publications and source records attributed to M Díaz.

At least 55 records · Page 3Linked to original sources
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

Cal-B-catalyzed alkoxycarbonylation of a-ring stereoisomeric synthons of 1alpha,25-dihydroxyvitamin D3 and 1alpha,25-dihydroxy-19-nor-previtamin D3: a comparative study. first regioselective chemoenzymatic synthesis of 19-nor-A-ring carbonates.

A comparative study of alkoxycarbonylation processes of both 19-nor-A-ring and A-ring stereoisomers of 1alpha,25-dihydroxyvitamin D3 analogues catalyzed by Candida antarctica lipase B (CAL-B) has been described. The presence of the methyl group in the A-ring at C-2, as in 3-6, has a determining role in the regioselectivity of the biocatalysis, mainly allowing the hydroxyl group at C-5 position to react. For the 19-nor-A-ring stereoisomers 7-10, which lack the C-2 methyl group, the configurations at C-3 and C-5 have a high influence in the selectivity exhibited by CAL-B. Thus, each couple of enantiomers showed opposing regioselectivities depending on the C-3 configuration. When C-3 possesses an (S)-configuration, enzymatic alkoxycarbonylations took place at the C-5-(R) or C-5-(S) hydroxyl groups. However, if the chiral centers at C-3 are (R), CAL-B alkoxycarbonylated the C-3-(R) hydroxyl group independently of the configuration at C-5. The corresponding carbonates are useful A-ring precursors of 1alpha,25-dihydroxyvitamin D3 analogues, selectively modified at the C-1 or C-3 positions. In addition, an improved synthesis of cis A-ring synthons 5 and 6 is described using a Mitsunobu methodology.

Calcitriol↗
PubMed2001

Controlled malolactic fermentation in cider using Oenococcus oeni immobilized in alginate beads and comparison with free cell fermentation.

Cells of Oenococcus oeni (formerly Leuconostoc oenos) immobilized in alginate beads were used as starter culture to conduct malolactic fermentation in cider production. Concentrations of major organic acids and volatile compounds were monitored during the process, and results were compared to those obtained when using free cells in the same conditions. The rates of malic acid consumption were similar but lower ethanoic acid content and higher concentration of alcohols were detected with immobilized cells. These features have beneficial effects on the organoleptic properties of cider. A comparison between the kinetic behavior in immobilized and free cells, based on the data obtained for the malic acid consumption, has been developed solving the homogeneous diffusion model when it is applied to the system with immobilized cells.

Journal Article↗
PubMed2001

Strategic environmental assessment of plans and programs: a methodology for estimating effects on biodiversity.

We developed a methodology for biodiversity evaluations within the process of Strategic Environmental Assessment and we applied it to the estimation of the effect of two Regional Plans of Development on all bird species inhabiting the Castilla y León region (northwestern Spain). The methodology is based on the evaluation of the effects of main development actions on the habitat requirements of species. From these evaluations, and from data on the current distribution and population size (number of individuals) of each species, we estimated the most likely pattern of distribution and population size after the full implementation of the plans for each species. The impacts of the plans were quantified as the differences between the pre- and postproject patterns after codifying them to compensate for differences in the quality of the information available among species. Overall, we conclude that the proposed methodology fulfills the requirements for its use within the SEA process as it allows for the assessment of cumulative impacts on every species, highlighting the development directions and the habitat types with major impacts, and ascertaining whether impacts affect species with either low or high conservation and/or economic value. Generalization of the proposed methodology to other regions or species will require wildlife-habitat models adequate for SEA analyses, so that we also propose guidelines for the development and validation of these models.

Animals↗
PubMed2001

Segmental heterogeneity in the biochemical properties of the Na+-K+-ATPase along the intestine of the gilthead seabream (Sparus aurata L.).

The activity of the Na+-K+-ATPase along the intestinal mucosa of the gilthead seabream has been examined. Under optimal assay conditions, found at 35 degrees C, pH 7.5, 2-5 mM MgCl2, 5 mM ATP, 10 mM K+ and 200 mM Na+, maximal Na+-K+-ATPase activities were found in the microsomal fraction of pyloric caeca (PC) and anterior intestine (AI), which were more than two-fold the activity measured in the microsomes from the posterior intestine (PI). Na+-K+-ATPase activities from PC, AI and PI displayed similar pH dependence, optimal Mg2+/ATP and Na+/K+ ratios, affinities for Mg2+ and ATP, and inhibition by vanadate. However, considerable differences regarding sensitivity to ouabain, inhibition by calcium and responses to ionic strength were observed between segments. Thus, Na+-K+-ATPase activity from the AI was found to be ten-fold more sensitive to ouabain and calcium than the enzyme from the PC and PI and displayed distinct kinetic behaviours with respect to Na+ and K+, compared to PC and PI. Analysis of the data from the AI revealed the presence of two Na+-K+-ATPase activities endowed with distinguishable biochemical characteristics, suggesting the involvement of two different isozymes. Regional differences in Na+-K+-ATPase activities in the intestine of the gilthead seabream are compared with literature data on Na+-K+-ATPase isozymes and discussed on the basis of the physiological differences between intestinal regions.

Adenosine Triphosphate↗
PubMed2001

Safety and preliminary immunogenicity of the recombinant outer membrane protein P64k of Neisseria meningitidis in human volunteers.

P64k is a meningococcal protein from Neisseria meningitidis that has been obtained by recombinant DNA technology. Recombinant P64k has been extensively characterized by physicochemical and immunological methods. Lately this protein has been found to act as a versatile immunological carrier for weak antigens in mice. In the present work, a Phase I clinical trial was carried out in healthy volunteers who received three inoculations of either placebo or recombinant P64k (20 or 50 microg). No severe adverse events occurred during the trial. Only mild adverse events in ten volunteers were observed. At 1 month after the third dose, 15 out of 18 volunteers (83.3%) who received the recombinant antigen had a P64k-specific antibody titre > or =1:100, as detected by ELISA. A fourth dose, given 9 months after the third one, elicited a potent booster immune response in P64k vaccinees. Accordingly, these P64k formulations were considered safe and immunogenic in healthy human volunteers.

Adult↗
PubMed2001

Organizing a public-sector vasectomy program in Brazil.

Although models of high-quality family planning services for men exist in Latin America, few if any have been organized within the complex and resource-constrained national public health systems. This study provides evidence from the Santa Barbara project in southern Brazil showing how vasectomy was introduced into the municipal health system. It demonstrates that once the necessary operational and quality-of-care improvements were in place, and sufficient political and technical support existed to proceed, it was possible to establish low-cost, well-used, and sustainable vasectomy services free of charge. The findings show that careful attention to the development of strong technical competence and an informed choice process resulted in high user satisfaction. Focus-group discussions with men who underwent vasectomy indicate that they had no objection to being served in the context of a women's health center and that they act as opinion leaders who draw an increasing clientele to the service.

Adult↗
PubMed2001

Immune response induction and new effector mechanisms possibly involved in protection conferred by the Cuban anti-meningococcal BC vaccine.

This report explores the participation of some afferent mechanisms in the immune response induced by the Cuban anti-meningococcal vaccine VA-MENGOC-BC. The induction of delayed-type hypersensitivity in nursing babies and lymphocyte proliferation after immunization is demonstrated. The presence of gamma interferon IFN-gamma and interleukin-2 (IL-2) mRNAs but absence of IL-4, IL-5, and IL-10 mRNAs were observed in peripheral blood mononuclear cells from immunized subjects after in vitro challenge with outer membrane vesicles. In addition, some effector functions were also explored. The presence of opsonic activity was demonstrated in sera from vaccinees. The role of neutrophils as essential effector cells was shown. In conclusion, we have shown that, at least in the Cuban adult population, VA-MENGOC-BC induces mechanisms with a T-helper 1 pattern in the afferent and effector branches of the immune response.

Adult↗
PubMed2001

Electrogenic Na(+)-dependent L-alanine transport in the lizard duodenum. Involvement of systems A and ASC.

L-Alanine transport across the isolated duodenal mucosa of the lizard Gallotia galloti has been studied in Ussing chambers under short-circuit conditions. Net L-alanine fluxes, transepithelial potential difference (PD), and short-circuit current (Isc) showed concentration-dependent relationships. Na(+)-dependent L-alanine transport was substantially inhibited by the analog alpha-methyl aminoisobutyric acid (MeAIB). Likewise, MeAIB fluxes were completely inhibited by L-alanine, indicating the presence of system A for neutral amino acid transport. System A transport activity was electrogenic and exhibited hyperbolic relationships for net MeAIB fluxes, PD, and Isc, which displayed similar apparent K(m) values. Na(+)-dependent L-alanine transport, but not MeAIB transport, was partially inhibited by L-serine and L-cysteine, indicating the participation of system ASC. This transport activity represents the major pathway for L-alanine absorption and seemed to operate in an electroneutral mode with a negligible contribution to the L-alanine-induced electrogenicity. It is concluded from the present study that the active Na(+)-dependent L-alanine transport across the isolated duodenal mucosa of Gallotia galloti results from the independent activity of systems A and ASC for neutral amino acid transport.

Alanine↗
PubMed2001

Guillain-Barré syndrome in Spain, 1985-1997: epidemiological and public health views.

Retrospective demographic information and hospital record data were collected for 337 patients resident in Spain who had validated Guillain-Barré syndrome (GBS) diagnoses and clinical onset during the period 1985-1997 and had been admitted to 11 centres, covering a population of 3.9 million. The European age-adjusted GBS incidence per 100,000 for 1985-1997 among the population aged 20 and over was 0.85, with a breakdown of 1.14 in men and 0.58 in women. Incidence increased with age and time, with occasional rises that mimicked outbreaks and occurred at irregular 2- to 4-year intervals, mainly in winter. Spatial variation was modest. Respiratory and gastrointestinal infections respectively constituted 49.3 and 19.3% of recorded preceding events. The 97.5% intercentile limit, obtained from the 1985-1997 monthly incidences using predictions from a Poisson model, was proposed as the threshold value for pilot epidemiological surveillance of GBS in 1998-1999.

Adult↗
PubMed2001

Arterial wall neovascularization induced by glycerol.

An intense and significant neovascularization, with numerous capillaries growing into the media layer of the rat femoral artery, was demonstrated when glycerol was administered into the interstitium between the femoral vein and the femoral artery. The maximum microvascularization was observed at days 7 and 9 after glycerol administration. Afterwards, involution of the majority of the newly-formed microvessels in the arterial wall occurred. Other substances containing glycerol in their molecules, such as triacetyl-glycerol and tributyril-glycerol, failed to produce significant neovascularization in the media layer of the femoral artery. Neovascularization of the arterial wall was preceded by a considerable decrease in the number of the smooth muscle cells, which experienced apoptosis and necrobiosis, disappearing in extense areas of the arterial segment affected by glycerol. Coinciding with neovascularization and microvascular involution, repopulation of the media layer by smooth muscle cells was observed.

Animals↗
PubMed2001

[Prognosis in children with biliary atresia successfully treated with Kasai's operation].

BACKGROUND: The Kasai procedure, portoenteroanastomosis (PEA) didn't reach international spreading until the seventy's decade, making difficult to find long-term results from children with ABE successfully treated with this technique. At our institution in the last fifteen years all the therapeutics procedures for these patients can be offered, including the liver transplant. AIM: To show the evolution of our patients with ABE treated with the PEA and that survive long-term without being transplanted. METHODS: The clinical course of 22 patients that survive more than 10 years after the PEA with their own liver is reviewed. The hepatic survival indexes of (success, death or transplant) are beyond the tenth year. The problems raised during the follow-up are analysed. RESULTS: From 99 patients with ABE treated primarily in our center, 22 reached the 10 year-old age after the PEA without a liver transplant. In the follow-up, seven if the these finally needed the transplant. Their median age was 12.2 year-old (range: 10.5-13.8) for a progressive hepatocellular damage in 5 cases associated to syndrome hepatopulmonar in two cases. The other fifteen patients have a compensated hepatopathy. Five of them do not have hyperesplenisme and the serum bilirrubine levels are lower than 1.3 mg/dL. The medium age of these patients at the end of the follow-up was 14.8 years. CONCLUSIONS: In spite of the reestablishment of the biliary flow with the PEA, few are the patients with ABE that preserve their hepatic function lapsed long periods of time. Nevertheless the prognosis of these patients is excellent.

Adolescent↗
PubMed2001

[Liver transplantation in infants younger than one year of age].

BACKGROUND: The development of the surgical techniques of hepatic division has maken that the young age (less than one year old) is no longer considered a risk factor in the pediatric liver transplant (TH). AIM: To show our experience with the TH in children younger than one year, comparing these results with the rest of the series and in second place to analyze if a bigger experience improves the results of the TH in this group of patients. METHODS: 44 patients that received a TH with less than a year of age are reviewed. Among them, 27 were in the last five years. The survival indexes of the graft and the patient are determined at 1, 5 and 10 years comparing them with three rest of the series. RESULTS: The grafts and patients survival was slightly inferior in the less than one year old, although in the last five years it improved 71.4% vs 82.1% at one year follow-up, and 61.9 in front of 74.5% at five years. The clinical situation of the patients that were transplanted before the year of life was worse: 43% (UNOS III, IV) in front of 13.1% in the same stadiums in the rest of the serie. In the younger patients, 54% of the grafts were reduced, versus 21% in the older. There were not a higher rate of complications in the young group. CONCLUSIONS: In spite of the difficulties of the TH in children younger than one year of age, the results are not very different from those obtained in the rest of the patients. In these results the experience of the transplant center have a great influence.

Humans↗
PubMed2001

Embryogenic cell suspensions from different explants and cultivars of Eragrostis curvula (Schrad.) Nees.

The aim of this work was the establishment of embryogenic calli and cell suspensions from different explants and cultivars of weeping lovegrass, Eragrostis curvula (Schrad.) Nees, to be used as targets for biolistic transformation. Calli were initiated from immature inflorescences, seeds, embryos, leaf bases and root tips. Modified MS medium (Murashige and Skoog, 1962) was used for calli induction and proliferation. Cell suspensions were established and maintained in AAF medium (Wang et al., 1993). Morphogenic calli, embryogenic cell suspensions of moderate growth rate--consisting mainly of compact proembryogenic cell clusters- and green plants were obtained from all the explants and cultivars assayed, except root tips. Both, explant and genotype were very important factors to be considered in order to obtain a morphogenic response and to establish cell suspensions from this grass. The statistical analysis detected interaction between both factors, explants and genotypes. Immature inflourescences were the best source of explant and Kromdraai was the cultivar that showed the best morphogenic response (expressed as the percentage of calli/explant and the percentage of calli with green spots--every green spot developed into green plants-) with inflourescences, embryos and leaf bases. For Morpa and Don Pablo embryos as explants were less responsive than seeds and leaf bases. There were no differences in leaf bases for all the three cultivars analysed.

Culture Techniques↗
PubMed2001

[Comparative study of health care costs for patients using home oxygen therapy or those in waiting lists].

BACKGROUND: Home oxygen therapy is the only intervention that significantly prolongs survival of patients with chronic obstructive pulmonary disease. Since this therapy is expensive, it is imperative to calculate its cost-benefit ratio. AIM: To compare health care costs for patients in a home oxygen therapy program, with those of a similar group of patients in a waiting list for this therapy. MATERIAL AND METHODS: A retrospective analysis of 21 patients on home oxygen therapy for 36 months or less and a group of 13 patients in the waiting list during a similar lapse. Medical consultations, drugs delivered and the cost of oxygen therapy were considered among ambulatory costs. Hospitalization costs included the number of days on regular or intermediary care beds, laboratory tests and drugs delivered. RESULTS: The annual health care costs for patients on home oxygen therapy were 709,656 Chilean pesos and the costs for patients in the waiting list were 797,320 Chilean pesos. CONCLUSIONS: The overall health care costs of home oxygen therapy are similar to the cost required by patients with chronic obstructive pulmonary disease remaining in waiting lists.

Aged↗