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R Rodríguez

Publications and source records attributed to R Rodríguez.

At least 145 records · Page 8Linked to original sources
PubMed1996

Diphenylpropionic acids as new AT1 selective angiotensin II antagonists.

The synthesis and pharmacological evaluation of a new series of potent AT1 selective diphenylpropionic acid nonpeptide angiotensin II receptor antagonists are reported. The new compounds were evaluated for in vitro AT1 (rat liver) and AT2 (rat adrenal) binding affinity as well as for in vivo inhibition of angiotensin II-induced increase in mean arterial blood pressure in pithed rats. Unsaturation of the diphenylpropionic acids as well as substitution or replacement by alkyl groups of the pendant phenyl ring resulted in a decrease of potency. On the other hand, the presence of small alkyl groups in the alpha-position to the carboxylic acid was important for activity, with one of the resultant diastereoisomers (R*,R*) being ca. 10-fold more active than the other (R*,S*). Oral evaluation of the most active compounds in a furosemide-treated sodium-depleted rat model showed that compound 36g (UR-7198) reduced blood pressure dose dependently. This compound showed in vitro and iv potencies similar to that of the reference compound losartan but faster onset of action and somewhat greater oral activity, presumably due to its improved bioavailability.

Administration, Oral↗
PubMed1996

Expression in Escherichia coli of Sin a 1, the major allergen from mustard.

Sin a 1, the major yellow mustard allergen, is a seed storage protein that belongs to the 2S albumin family. It is composed of two disulfide-bonded polypeptide chains. The cloning of this allergen has been carried out by means of the polymerase chain reaction using non-degenerate oligonucleotides encoding the N-terminal and C-terminal regions of the mature protein as primers. Five genomic nucleotide sequences have been analyzed, encoding both mature polypeptide chains linked by the internal processed fragment. The sequence data show the existence of microheterogeneities at ten positions, demonstrating the polymorphism exhibited by the natural protein. One of the genomic clones was expressed in Escherichia coli by fusion to glutathione S-transferase from Schistosoma japonicum. The resulting chimeric protein was purified by affinity chromatography on a glutathione-Sepharose 4B matrix, and digested with thrombin to release the recombinant allergen. The recombinant Sin a 1 is recognized by rabbit polyclonal and mouse monoclonal antisera raised against natural Sin a 1, as well as by the IgE of mustard-sensitive human sera. In addition, recombinant Sin a 1 possesses a high resistance to trypsin digestion, like the native mustard allergen.

Allergens↗
PubMed1996

[Rates of human immunodeficiency virus (HIV) infection in intravenous drug addicts from the Barcelona area, according to sex and age of drug consumption onset].

BACKGROUND: The differences in the rates of HIV infection in intravenous drug addicts according to the age of onset of drug consumption, sex and length of intake were evaluated. METHODS: The study sample was made up of 650 intravenous drug addicts (535 males and 115 females) admitted to a Hospital Detoxication Unit over 7 years (1987-1993). Of all these patients HIV serology and a questionnaire related to sociodemographic variables and drug consumption (age, sex, year of onset of intravenous drug intake, length of addiction and year of admission) were obtained. RESULTS: The rate of HIV infection for any length of addiction was higher in females than in males with this difference being significant for a length of addiction of less than 24 months (p = 0.03). The greater the age of onset in the use of intravenous drugs the lower the rate of HIV infection (p < 0.0001). In addiction times of less than 24 months the subjects who began drug consumption at an earlier age than the mean (19 years) presented significantly higher HIV infection rates (p = 0.04). CONCLUSIONS: Among the intravenous drug consumers in the area of Barcelona, Spain subgroups may be found: those who enter the consumption of intravenous drugs early and women, demonstrating high rates of HIV seroprevalence from the onset of their addiction.

Adult↗
PubMed1996

Surface Complexation at the TiO(2) (anatase)/Aqueous Solution Interface: Chemisorption of Catechol.

Catechol adsorbs at the TiO(2) (anatase)/aqueous solution interface forming inner-sphere surface complexes. The UV-visible differential reflectance spectrum of surface titanium-catecholate complexes presents a band centered at 420 nm which corresponds to the ligand to metal charge transfer transition within the surface complexes. At pH values below pK(a1), the surface excess of catechol is almost insensitive toward pH and presents a Langmuirian dependence with the concentration of uncomplexed catechol. The ratio Gamma(max):N(S) (N(S) being the measured density of available OH surface groups) indicates a prevailing 1 to 2 ligand exchange adsorption stoichiometry. In the range pH >/= pK(a1), the catechol surface excess decreases markedly with increasing pH. Formation of 1 to 1 surface complexes produces an excess of negative surface charge that is revealed by the shift of the iep to lower pH values. The reported data, which are supplemented with information on the charging behavior of TiO(2) suspended in indifferent electrolyte solutions, are interpreted in terms of the multi-site surface complexation model. In this model, two types of surface OH groups are considered: identical withTiOH(1/3-) and identical withOH(1/3+). Although both surface groups undergo protonation-deprotonation reactions, only identical withTiOH(1/3-) are prone to chemisorption.

Journal Article↗
PubMed1996

Differential effects of transforming growth factor-beta 1 on IgA vs. IgG2b production by lipopolysaccharide-stimulated lymph node B cells: a comparative study with spleen B cells.

Transforming growth factor-beta 1 (TGF-beta 1) is a multifunctional cytokine that promotes IgA/IgG2b switching and secretion. Here, we show a differential effect of TGF-beta 1 on Ig production by lipopolysaccharide-stimulated spleen and lymph node (LN) B cells. Exogenous TGF-beta 1 increased IgA production in B cell cultures and IgG2b production by spleen B cells. In contrast, IgG2b was suppressed by TGF-beta 1 in cultures of LN B cells, although endogenous TFG-beta was required for IgG2b production in LN B cell cultures. The suppressor properties of exogenous TGF-beta 1 (0.5 ng/ml) on IgG2b production by LN B cells were also seen when testing IgG1 or IgG2a induced by interleukin-4 or interferon-gama, respectively. These differences between B cells from each lymphoid tissue appeared to be related to a different TGF-beta antiproliferative effect, since proliferation of LN B cells was extremely sensitive to TFG-beta 1 and IgG2b production was more sensitive than IgA to the TFG-beta-mediated suppression. However, by counteracting the antiproliferative effect of TGF-beta 1 with a CD40 agonistic mAb (IC10), the IgG2b response by LN B cells was still lacking. IC10 was nevertheless inhibitory for IgG2b production in most cases, while increasing secretion of IgA in the very same cultures. Taken together, the results suggest that functional differences between spleen and LN B cells do exit, at least with regard to the immunomodulating properties of TGF-beta on both proliferation and Ig production. Moreover, functional differences exist between cells committed for IgA and IgG2b regarding their sensitivity to the antiproliferative activity of TGF-beta 1 and the effect of CD40-derived signals on Ig secretion.

Animals↗
PubMed1996

Nigericin-induced Na+/H+ and K+/H+ exchange in synaptosomes: effect on [3H]GABA release.

The effect of the putative K+/H+ ionophore, nigericin on the internal Na+ concentration ([Nai]), the internal pH (pHi), the internal Ca2+ concentration ([Cai]) and the baseline release of the neurotransmitter, GABA was investigated in Na+-binding benzofuran isophtalate acetoxymethyl ester (SBFI-AM), 2',7'-bis(carboxyethyl)-5(6) carboxyfluorescein acetoxymethyl ester (BCECF-AM, fura-2 and [3H]GABA loaded synaptosomes, respectively. In the presence of Na+ at a physiological concentration (147 mM), nigericin (0.5 microM) elevates [Nai] from 20 to 50 mM, increases the pHi, 0.16 pH units, elevates four fold the [Cai] at expense of external Ca2+ and markedly increases (more than five fold) the release of [3H]GABA. In the absence of a Na+ concentration gradient (i.e. when the external Na+ concentration equals the [Nai]), the same concentration (0.5 microM) of nigericin causes the opposite effect on the pHi (acidifies the synaptosomal interior), does not modify the [Nai] and is practically unable to elevate the [Cai] or to increase [3H]GABA release. Only with higher concentrations of nigericin than 0.5 microM the ionophore is able to elevate the [Cai] and to increase the release of [3H]GABA under the conditions in which the net Na+ movements are eliminated. These results clearly show that under physiological conditions (147 mM external Na+) nigericin behaves as a Na+/H+ ionophore, and all its effects are triggered by the entrance of Na+ in exchange for H+ through the ionophore itself. Nigericin behaves as a K+/H+ ionophore in synaptosomes just when the net Na+ movements are eliminated (i.e. under conditions in which the external and the internal Na+ concentrations are equal). In summary care must be taken when using the putative K+/H+ ionophore nigericin as an experimental tool in synaptosomes, as under standard conditions (i.e. in the presence of high external Na+) nigericin behaves as a Na+/H+ ionophore.

Animals↗
PubMed1996

Distribution, origin and fate of chromium in soils in Guanajuato, Mexico.

Total, hexavalent and trivalent chromium were determined in surface and 30-cm depth soil samples from a highly chromium-polluted area in Guanajuato state, central México. Four samples were also analyzed by a sequential extraction procedure. Nearly 0.9 km(2) out of the 8 km(2) area sampled was polluted with chromium, at concentrations up to 12960 mg kg(-1), mostly as Cr(III). Concentrations of Cr(VI) were lower than 0.5 mg kg(-1) in most sampled points, with the exception of one, where the concentration was found to be 65.14 mg kg(-1). Chromiumcontaining dust from a chromate factory accounted for most of the contamination. The highest concentrations of hexavalent chromium in soil, were in the bottom sediments of an abandoned water reservoir used to store polluted water from a well, before use of the water in the factory process. Tannery wastes, dust from a sanitary landfill of chromate compounds and the transport of chromium products are the sources of chromium at other sites. Chromium is fixed preferentially in the hydrous Fe and Mn oxides in the more polluted soils. Less polluted soils have a high proportion of chromium associated with the sulfide and organic fraction. Cr(III) is retained preferentially in the superficial soil layer. Variations in the physical characteristics of the soil, relative abundance of the various soil components and characteristics of the contaminant source, give rise to differences in chromium soil concentrations with depth.

Journal Article↗
PubMed1996

Cross-reactivity between the major allergen from olive pollen and unrelated glycoproteins: evidence of an epitope in the glycan moiety of the allergen.

Ole e 1, the major allergen from olive pollen, is a glycoprotein containing a single Asn-linked glycan moiety. Rabbit antiserum against this protein has been obtained; and its immunologic cross-reactivities in Western blotting with ascorbate oxidase, horseradish peroxidase, bromelain, ovalbumin, and honeybee venom phospholipase A2 have been studied. Ascorbate oxidase, peroxidase, and bromelain are recognized by the Ole e 1 antiserum. When these three proteins are deglycosylated by periodate treatment, such an immunologic reaction does not occur. The relative affinities of these proteins have been analyzed by direct and inhibition ELISA experiments. A commercially available antibody against horseradish peroxidase has also been considered in these studies. This antibody reacts with Ole e 1 but not with the periodate-deglycosylated allergen. Horseradish peroxidase, bromelain, and ascorbate oxidase are recognized by the IgE of sera from patients who are hypersensitive to olive tree pollen. This binding is also abolished by periodate treatment. The results are interpreted in terms of the presence of an epitope in the carbohydrate moiety of Ole e 1, which would contain a xylose involved in recognition by both IgE and IgG antibodies.

Allergens↗
PubMed1996

[Diet and migraine].

Some foods in our diet can spark off migraine attacks in susceptible individuals. Some foods can bring an attack on through an allergic reaction. A certain number such as citrus fruits, tea, coffee, pork, chocolate, milk, nuts, vegetables and cola drinks have been cited as possible allergens associated with migraine. This mechanism has however been criticized: an improvement in symptoms by eliminating some food(s) from our diet does not necessarily mean an immunologically based allergic reaction. The high IgE incidence rate is not greater in such patients than in the population at large. Other allergic reactions unrelated to diet may also be associated with migraine attacks. On the other hand substances in food may be the cause of modifications in vascular tone and bring migraine on in those so prone. Among such substances are tyramine, phenylalanine, phenolic flavonoids, alcohol, food additives (sodium nitrate, monosodium glutamate, aspartame) and caffeine. Another recognized trigger for migraine is hypoglycemia. Such foods as chocolate, cheese, citrus fruits, bananas, nuts, 'cured' meats, dairy products, cereals, beans, hot dogs, pizza, food additives (sodium nitrate, monosodium glutamate in Chinese restaurant food, aspartame as a sweetener), coffee, tea, cola drinks, alcoholic drinks such as red wine, beer or whisky distilled in copper stills, all may bring on a migraine attack. For every patient we have to assess which foodstuffs are involved in the attack (not necessarily produced by consuming the product concerned) in order to try to avoid their consumptions as a means of prophylaxis for migraine.

Diet↗
PubMed1996

[Description of 31 pediatric cases of infection caused by human Parvovirus B 19].

FUNDAMENTALS: [corrected] Human Parvovirus B19 has been identified as the etiological agent implicated in several clinical forms of disease. The aim of this study was to define the clinical aspects observed in the children with human parvovirus infection in our hospital. METHODS: A retrospective study was done in 31 pediatric cases observed in our hospital from January-92 to July-94; all had positive IgM against Parvovirus (determined by enzymoinmunoanalysis). RESULTS: The most frequent signs and symptoms were fever in 66.6% of the cases and skin findings in 48%, manifested as typical infectious erythema in 26% and polimorphic nonspecific exanthema in the rest. There were variable blood manifestations, observed in 11 children (35%): Immune Thrombocytopenic purpura, Chronic anemia in immunocompromised hosts, bone marrow erithrophagocytosis and hemolytic crises in non-hemolytic anemia patients. The abnormal blood findings were mostly observed in children with compromised immunity. Articular disease was presented in four children (12%). Long lasting fever was observed in only one case. CONCLUSIONS: In our sample the diversity of clinical forms of presentation of Parvovirus B19 infection is well documented as it is reported by several authors. Although other studies as polymerase chain reaction (PCR), nucleic acid hybridization, direct visualization of the virus or its particles, or viral antigen detection are desirable to confirm the serologic studies.

Adolescent↗
PubMed1996

[3 year survival in patients hospitalized for acute cerebrovascular disorders].

For three years we studied the mortality and functional situation of all patients admitted in 1991 to the Neurology Service suffering from acute stroke with the exception of subarachnoid haemorrhage cases. We analyzed the cause of death whether directly related to the initial illness or not. Out of 134 patients admitted for acute stroke, 48 (41.02% of the 117 patients examined after excluding 17 whom we did not obtain complete information from) had died after three years. The main causes of death were directly related to acute stroke (37.5%) and pneumonia (37.5%). Death occurred mainly in the first month (79.16% of deaths). Predictive variables for mortality directly related to acute stroke during the first month include severe weakness, brain haemorrhage, dysphasia and earlier incidence of acute stroke. Variables related to higher mortality rate due to other causes in the first month were dysphasia, age and angina antecedents, whereas earlier incidence of acute stroke was associated with a lesser mortality rate for these causes, as distinct from acute stroke itself. Greater levels of weakness and sphincteral incontinence are the best predictive signs of dependency functional situation at the end of the first month and, along with diabetes, after one and three years.

Acute Disease↗
PubMed1996

Antineutrophil cytoplasmic antibodies in relatives of patients with inflammatory bowel disease.

BACKGROUND: The occurrence of antineutrophil cytoplasmic antibodies (ANCA) has been reported more frequently than expected in healthy first-degree relatives of patients with ulcerative colitis, suggesting that these antibodies may represent a subclinical marker of genetic disease susceptibility. AIM: To determine the prevalence of ANCA in unaffected first-degree relatives of inflammatory bowel disease patients in a Spanish population. METHODS: Three hundred and seventy sera obtained from 80 patients with inflammatory bowel disease (55 ulcerative colitis, 25 Crohn's disease), 217 unaffected first-degree relatives (157 from ulcerative colitis and 60 from Crohn's disease patients), 62 healthy controls, and 11 celiac disease patients were tested using an indirect immunofluorescence assay. RESULTS: Antibodies were detected in 64% of patients with ulcerative colitis but in only 12.5% of patients with Crohn's disease. ANCA were seldom present in their unaffected first-degree relatives (4.6%), control subjects (1.6%), and celiac disease patients (0%). CONCLUSIONS: In the Spanish population studied, antineutrophil cytoplasmic antibodies occur more commonly in ulcerative colitis than in Crohn's disease, as reported in other Caucasian populations. Moreover, their presence is not increased in their first-degree relatives. These findings indicate that ANCA are not a subclinical marker of genetic susceptibility to inflammatory bowel disease in this population.

Adult↗
PubMed1996

[Sclerotherapy of post-renal transplantation lymphocele with percutaneous instillation of amidotrizoate].

Incidence of post-renal transplant (RT) lymphocele varies between 0.6% to 41% depending on the author. Therapeutical management of these entities is controversial. (Open or laparoscopic) surgical marsupialization of the peritoneal cavity, percutaneous drainage, and percutaneous sclerosis with povidone-iodine are all valid options to treat post-RT lymphocele. This paper presents two cases of symptomatic post-RT lymphocele not suitable for laparoscopic treatment, which were resolved by intracavitary instillation of Sodium Amidotrizoate 76%. The first case had been previously treated with povidone-iodine with no resolution, also maintaining a 500 ml/24h deficit. In the second case, instillation with Sodium Amidotrizoate 76% was considered first choice approach. In both instances the lymphocele deficit ceased with instillation intervals of 6 and 14 days, respectively. In brief, percutaneous sclerosis with Amidotrizoate can be a valid alternative for the treatment of post-RT lymphocele.

Adult↗
PubMed1996

[Effect of the local anesthetic on visceral pain in cesarean sections done under intradural anesthesia].

OBJECTIVES: To evaluate the influence of local anesthetic on the incidence and severity of visceral pain during cesarean section performed under subarachnoid anesthesia. PATIENTS AND METHOD: This was a randomized double blind study of 90 parturients undergoing scheduled or emergency cesareans. The women were distributed among three groups according to local anesthetic used: 2% isobaric mepivacaine in group 1, 0.5% hyperbaric bupivacaine in group 2, and 0.5% isobaric bupivacaine with adrenalin in group 3. The total anesthetic dose was selected based on height, and pain was defined as silent and dull, or a sensation of pressure that was poorly defined, diffuse or referred to another area and accompanied or not by nausea and/or vomiting. Pain was assessed on a visual analog scale at various moments during surgery. Other variables recorded were metameric level of blockade, hemodynamic function and presence of nausea and/or vomiting. RESULTS: One patient in each group was excluded. The incidences of visceral pain and 95% confidence intervals were as follows: 38% (23-56%) in group 1 and 10% (3.5-25%) in groups 2 and 3 (p = 0.002). The metameric level of blockade differed significantly among the groups. The highest level (T1-5) was reached in group 1 but level was the most consistent (T3-5) in group 2. Systolic arterial pressures in all groups were significantly lower than baseline levels 5 min after puncture and the decrease was greatest in group 3. The highest incidence (p = 0.01) of nausea and/or vomiting occurred in the isobaric bupivacaine group. CONCLUSION: Use of hyperbaric bupivacaine offers advantages over the other techniques, as it assures more consistent attainment of metameric level, an incidence of visceral pain that is lower than that of isobaric mepivacaine, and fewer hemodynamic repercussions than isobaric bupivacaine with vasoconstrictor.

Adult↗
PubMed1996

[Dengue in Nicaragua, 1994: reintroduction of serotype 3 in the Americas].

The principal aim of this work was to report the reintroduction of dengue virus serotype 3 in the Americas after an absence of 17 years. In addition, it describes the most common symptoms associated with classical dengue and hemorrhagic dengue and presents data on the distribution of the epidemic in the various comprehensive local health care systems of Nicaragua. The study group consisted of 39 patients hospitalized in Managua and León for dengue with hemorrhagic manifestations and hemorrhagic dengue. Of these patients, 34 were classified as probable or confirmed cases of dengue. The most frequent symptoms were fever, headache, vomiting, and muscle and joint pains. The tourniquet test was positive and thrombocytopenia was confirmed in 56% and 44% of the patients, respectively. Epistaxis (67%) was the most common hemorrhagic sign. Of the 356 serum samples received through the dengue surveillance systems in October 1994, IgM antibodies were detected in 43%. The virus was isolated from 5 of 24 samples tested (serotype 3 from 3 and serotype 1 from 2). The reintroduction of serotype 3 of dengue into the Region was demonstrated, along with its ability to produce epidemics of hemorrhagic dengue. The countries are warned that if they do not quickly take the measures described in the guidelines for the prevention and control of dengue and dengue hemorrhagic fever, new epidemics may occur in the Americas, given the large number of persons susceptible to this serotype and the high density of the mosquito vector in most of the countries of the Region.

Adolescent↗
PubMed1996

Isolation, cDNA cloning and expression of Lig v 1, the major allergen from privet pollen.

BACKGROUND: An olive allergen-like protein has been detected in privet pollen. This protein could be involved in the allergenic cross-reactivity described for privet and olive tree pollen extracts. OBJECTIVE: Isolation and characterization of natural Lig v 1. Cloning and expression of its cDNA in order to assess its structural similarity with the olive allergen. METHODS: Current chromatographic methods were used to isolate the privet counterpart of Ole e 1. A pool of sera from subjects allergic to olive tree pollen was used to immunodetect the protein in the elution profiles. Ole e 1-specific polyclonal antibody and allergic sera were used in immunoblotting assays of the isolated protein. Polymerase chain reaction amplification of the first strand cDNA synthesized from the privet pollen total RNA was carried out to prepare a full-length fragment encoding Lig v 1. After nucleotide sequencing, expression of one clone was performed in Escherichia coli, under the form of a fusion protein with glutathione S-transferase. The IgE binding capability of the recombinant protein was also analysed. RESULTS: The major allergen from privet pollen. Lig v 1, was purified to homogeneity by two gel filtration chromatographies and one reverse-phase high-performance liquid chromatography. Its amino acid composition and N-terminal amino acid sequence were determined. Two different clones encoding Lig v 1 were sequenced. Strong sequence similarity between Lig v 1 and Ole e 1 was observed, the identity being 85 and 96%. One of the sequenced clones was expressed and the recombinant product exhibited IgG and IgE binding activities against both anti-Ole e 1 polyclonal antibodies and olive-allergic sera. CONCLUSION: Privet pollen contains a protein structurally and immunologically related to the major allergen of olive pollen. The similarity exhibited by these proteins could explain the cross-reactivity observed between the two pollen extracts. Since these allergens are highly polymorphic, the expression of an immunologically active recombinant Lig v 1 will permit the preparation of well defined molecules for both research and clinical purposes.

Allergens↗
PubMed1996

[Genetic relatedness of the dengue 3 virus isolated in the outbreak of dengue hemorrhagic fever in Nicaragua, 1994].

It is reported the isolation of 2 dengue strains, 3 in samples from Nicaraguan patients suffering from dengue with hemorrhagic manifestations, which showed the reintroduction of this serotype in the region after being 17 years out of circulation. It is also reported the genetic characterization of the isolated strain, which, according to its classification, belongs to the group of dengue 2 strains isolated in Southeast Asi and which have been associated to hemorrhagic dengue. These results suggest the origin of this strain.

Amino Acid Sequence↗