Biomedical subjects

R Rodríguez

Publications and source records attributed to R Rodríguez.

At least 181 records · Page 10Linked to original sources

PubMed1994

Ammonium-sensitive protein kinase activity in plasma membranes of the cyanobacterium Anacystis nidulans.

Cytoplasmic membranes prepared from nitrate-grown Anacystis nidulans cells exhibit a Mg(2+)-dependent protein kinase activity able to phosphorylate in vitro plasma membrane polypeptides with molecular masses of 98, 93, 83, 47, 44 and 31 kDa. The protein kinase activity was inhibited in cytoplasmic membrane preparations from nitrate-grown cells which had been exposed to ammonium for 5 min. Parallely, ammonium exposure also resulted in a more than two-fold activation of an alkaline phosphatase activity present in the soluble fraction. These results are discussed in relation to the well-known inhibition by ammonium of nitrate transport activity, and a hypothesis for the regulatory mechanism involved is presented.

Alkaline Phosphatase↗

PubMed1994

Cloning and expression of Ole e I, the major allergen from olive tree pollen. Polymorphism analysis and tissue specificity.

Ole e I, the major allergen from the olive tree (Olea europaea), is one of the main causes of allergy in Mediterranean countries and some areas of North America. The cloning and sequencing of several cDNAs coding for the olive allergen have been achieved. cDNA has been synthesized from total pollen RNA and amplified by using the polymerase chain reaction. The nucleotide sequence data demonstrate the existence of microheterogeneities in at least 37 positions out of the 145 amino acids of Ole e I, thus explaining the high degree of polymorphism exhibited by the natural protein. One of the sequenced cDNAs encoding a full-length isoform was inserted into the plasmid vector pGEX-2T and overexpressed. The recombinant Ole e I has been produced in Escherichia coli as a fusion protein with glutathione S-transferase of Schistosoma japonicum. This chimeric protein was purified by affinity chromatography on a glutathione-Sepharose 4B column and digested with thrombin to release the recombinant allergen. Both the fusion protein and the recombinant Ole e I were recognized in Western blot analysis by rabbit polyclonal and mouse monoclonal antisera raised against native Ole e I as well as by the IgE of olive pollen-sensitive human sera. This indicates that the recombinant production of individual isoforms may be useful for the improvement of reagents to be used in diagnosis and therapy of IgE-mediated disorders. In addition, Ole e I mRNA has been observed to be pollen-specific as shown in a Northern blot analysis.

Allergens↗

PubMed1994

Isolation and characterization of an olive allergen-like protein from lilac pollen. Sequence analysis of three cDNA encoding protein isoforms.

An olive allergen-like protein has been isolated from lilac (Syringa vulgaris) pollen extract. The protein can be considered as an allergen since is recognized by IgE from olive hypersensitive human sera, and has been called Syr v I (IUIS nomenclature). This protein consists of a glycosylated polypeptide of 20 kDa, which has an amino acid composition, spectroscopic properties, and an N-terminal sequence similar to the major allergen from olive pollen, Ole e I. The lilac allergen is recognized by rabbit polyclonal antisera raised against olive allergen as well as by an Ole e I-specific monoclonal antibody. Using a polymerase chain reaction strategy, based on the similarities observed between these olive and lilac proteins, three cDNA clones encoding Syr v I have been isolated and sequenced. These clones code for a polymorphic protein of 145 residues with a derived molecular mass of about 16,400Da, which contains a potential N-glycosylation site. Comparison of the deduced amino acid sequences of these Syr v I isoforms to each other revealed identities of 90-97%. Moreover, these sequences showed a high degree of similarity (85.5-89.6% identity) with Ole e I. The structural and immunological characterization of Syr v I justify the cross-reactions observed between olive and lilac pollen extracts. The molecular cloning of Syr v I is relevant for the epitope mapping in Oleaceae allergens, and may contribute to an improvement in the design of reagents for diagnosis and therapy of IgE-dependent allergic reactions.

Allergens↗

PubMed1994

[Neutrophil anticytoplasmic antibodies: their diagnostic utility in vasculitis and glomerulonephritis].

BACKGROUND: The prevalence and diagnostic usefulness of antineutrophil cytoplasmic antibodies (ANCA) were analyzed in a series of patients with different types of vasculitis, connective tissue diseases, nephropathies and lung diseases. METHODS: Six hundred seventy-six consecutive patients with systemic vasculitis, connective tissue diseases, nephropathies and different lung disturbances were included in the study. The ANCA were determined by indirect immunofluorescence (IIF) on neutrophils fixed in ethanol. For the detection of antimyeloperoxidase (MPO) antibodies (Ab) a new technique was developed consisting in the performance of IIF on neutrophils with a deficiency in MPO. The serologic samples were also analyzed by enzyme-linked immunosorbent assays with MPO and purified proteinase 3 (PR3). RESULTS: ANCA were demonstrated in 95 patients. A cytoplasmic pattern (c-ANCA) was detected in 25 cases (26%) and in 70 (74%) a perinuclear pattern (p-ANCA) was observed. Twenty-one of the 25 cases (84%) of c-ANCA corresponded to anti-PR3 Ab and 61 of the 70 (87%) of p-ANCA corresponded to anti-MPO Ab. The anti-PR3 Ab identified Wegener's granulomatosis, with a sensitivity and specificity for the generalized and clinically active forms being 65 and 88%, respectively. The anti-MPO Ab were principally detected in patients with rapidly progressive glomerulonephritis (RPGN) and hemorrhagic alveolar capillaritis. The sensitivity and specificity of the anti-MPO Ab for the RPGN and alveolar capillaritis were 75% and 98%. CONCLUSIONS: Two principal subtypes of ANCA may be detected, which also recognize two fundamental clinicopathologic entities. The high diagnostic sensitivity and specificity of these antibodies for each of the processes to which they are associated can justify the adoption of therapeutic measures in determined cases.

Antibodies, Antineutrophil Cytoplasmic↗

PubMed1994

The role of nitric oxide in the transformation of visual information within the dorsal lateral geniculate nucleus of the cat.

We have shown that application of an inhibitor of the enzyme nitric oxide synthase (NOS) effectively suppresses the visual responses of relay cells in the dorsal lateral geniculate nucleus (dLGN) of the anaesthetized paralysed cat. Such suppression seems to result from a specific reduction in transmission via N-methyl-D-aspartic acid (NMDA) receptors, since iontophoretic application of the inhibitor of NOS selectively and in a dose-dependent manner decreased the responses to exogenously applied NMDA. Responses to other exogenously applied amino acid agonists, such as quisqualate (Quis), kainate (Kain) and alpha-amino-3-hydroxy-5-5-methyl-4-isoxazole-propionic acid (AMPA) were largely unaffected. Furthermore, the excitatory action of acetylcholine (ACh), normally co-localized with NOS in axonal terminals within the dLGN arising from the brainstem, was also unaffected. Unlike some other actions of nitric oxide (NO), this role seems not to involve an increase in production of cyclic guanosine-3',5'-mono-phosphate (cGMP), since application of the membrane permeable cGMP analogue 8-bromo-cGMP did not alter the suppressive effect of NOS inhibitors on either visual or NMDA evoked responses. We conclude that the normal function of NO at this level of the visual system is permissive, allowing full expression of NMDA mediated visually elicited information.

Amino Acid Oxidoreductases↗

PubMed1994

Glycosylation site of the major allergen from olive tree pollen. Allergenic implications of the carbohydrate moiety.

The electrophoretic analysis of purified Ole e I, the major allergen from Olea europaea pollen, reveals the presence of two main variants, glycosylated (20.0 kDa) and non-glycosylated (18.5 kDa) components. The glycosylated variant has been identified as a concanavalin A-binding glycoprotein. Its carbohydrate moiety has a molecular mass of about 1.3 kDa (5% weight of the glycosylated allergen), based on mass spectrometry analysis. Enzymatic treatment of native Ole e I with the specific glycosidase PNGase F accounts for an oligosaccharide N-linked to the polypeptide chain. This treatment does not sensibly modify the secondary structure of the protein but diminishes the affinity of the allergen for specific IgE antibodies. Tryptic digestion of Ole e I reveals the presence of a single carbohydrate-containing peptide. This peptide was recognized by the sera of hypersensitive individuals. The amino acid sequence of this peptide is Phe-Lys-Leu-Asn-Thr-Val-Asn-Gly-Thr-Thr-Arg, asparagine at the seventh being the carbohydrate attaching site. The obtained data are discussed in terms of the potential role of the sugar moiety in the allergenic activity of Ole e I.

Allergens↗

PubMed1994

Endogenous polyamine concentrations in juvenile, adult and in vitro reinvigorated hazel.

We investigated endogenous polyamine concentrations in leaves from juvenile and mature hazel (Corylus avellana L.) shoots, as well as leaves from shoots obtained by both forced outgrowth and micropropagation of adult tissues. To determine if the observed in vitro reinvigoration was associated with polyamine metabolism, we tested the effect of serial subcultures on polyamine concentrations. Polyamines, mostly free putrescine, were higher in juvenile tissues. Adult tissues micropropagated for 14 subcultures had polyamine concentrations characteristic of juvenile tissues. However, with additional subcultures, total polyamine concentrations decreased. The putrescine to spermidine plus spermine ratio was higher in juvenile and micropropagated tissues than in adult tissues, but decreased in micropropagated tissues after 20 subcultures. This ratio may reflect a balance between vegetative growth and reproductive processes. Thus, an analysis of polyamine concentrations may provide a simple assay for determining the juvenility of plant tissues and, hence, their suitability for micropropagation.

Journal Article↗

PubMed1994

Abnormal leukotriene C4 released by unaffected jejunal mucosa in patients with inactive Crohn's disease.

The mucosal release of inflammatory mediators is enhanced in active inflammatory bowel disease. This study examines whether leukotriene C4 production occurs in apparently unaffected segments of the gut. The intraluminal release of leukotriene C4 was determined by jejunal perfusion in seven healthy controls, in nine patients with chronic ulcerative colitis, and in 13 patients with Crohn's disease (six with ileal disease, and seven with only colonic). All patients were in clinical remission and none of them had evidence of jejunal involvement. Mild intraluminal irritation with a 2.5 mmol/l deoxycholic acid solution was induced to stimulate local inflammatory mechanisms. The release of DNA (a marker of mucosal desquamation) and prostaglandin E2 (PGE2) was simultaneously measured. Jejunal release of DNA was higher in Crohn's disease patients than in ulcerative colitis or healthy controls. Basal release of PGE2 was similar in the three groups of patients. Basal release of leukotriene C4 was considerably enhanced, however, in Crohn's disease patients compared with healthy controls. In ulcerative colitis patients, basal leukotriene C4 release was non-significantly different from controls. Bile acid perfusion stimulated PGE2, leukotriene C4, and DNA release in all groups studied, but leukotriene C4 release was significantly higher in Crohn's disease patients. It is concluded that in inactive Crohn's disease there is an enhanced intraluminal release of leukotriene C4 in apparently unaffected segments of proximal small bowel, which may reflect fundamental changes in the function of the gut mucosal barrier.

Adult↗

PubMed1994

[Cardiovascular response to exercise at high altitude in workers chronically exposed to intermittent hypobaric hypoxia].

The isotonic work performance was assessed in 34 workers aged 35 +/- 5.8 years old that had working shifts of four days at 4500 m over the sea level and resting periods of other four days at the sea level during at least two years. Subjects were assessed in one occasion at the sea level, and at the first and fourth day of the working shift at 4500 m over the sea level. Resting arterial oxygen saturation in these three periods was 97 +/- 1.1, 88 +/- 18 and 91 +/- 1.1% respectively (p < 0.01), and markedly decreased during maximal and submaximal exercise at 4500 m over the sea level. Exercise duration in the three periods was 931 +/- 210, 775 +/- 105 and 778 +/- 105 seg respectively (p < 0.001). Heart rate in the resting period was at least 10% higher and maximal and submaximal rates were lower at high altitude. No differences in blood pressure or packed red cell volume were observed. Exercise duration correlated inversely with age (r = -0.49 p = 0.03) and directly with maximal heart rate (r = 0.44 p = 0.009) at the sea level. No correlation between aerobic capacity and other measured parameters was observed. These results show no differences in the cardiovascular response to exercise between the first and fourth day of stay at high altitude in workers chronically exposed to intermittent hypobaric hypoxia.

Adult↗

PubMed1994

[Duplex sonography in the diagnosis of deep venous thrombosis in the lower limbs].

Duplex ultrasonography (DUS) has shown high sensitivity and specificity in the diagnosis of proximal deep vein thrombosis (DVT). It is now considered the initial procedure of choice for the evaluation of this entity because of its advantages (low cost, non invasiveness, no need for contrast media, no ionizing radiation) and because of the possibility of making other diagnoses, v.g. Baker's cyst. With the development of color Doppler, this study has become easier and now includes the calf and iliac vessels. Nevertheless, it has not improved the sensitivity and specificity of DUS. Phlebography, until now the "golden standard", has become a "second choice" procedure for proximal DVT but it continues to be of value in the evaluation of calf veins, which are more difficult to evaluate with DUS, and other venous pathology.

Adolescent↗

PubMed1994

[Adverse reactions to high osmolarity contrast media. A comparative-prospective study].

The purpose of this study was to verify and compare the different types of reactions to iodinated contrast media available at the Social Security Metropolitan Hospital Complex: Conray 60%, Vascoray and Uromiron. These are ionic, high osmolality compounds. The authors found that, in 400 patients not only the osmolality had an important role in the reactions observed, but that the intrinsic nature of the molecule of the contrast medium used was the determining factor.

Adolescent↗

PubMed1994

[Solid and papillary epithelial neoplasm of the pancreas. Report of 2 cases].

Solid and papillary epithelial tumor of the pancreas occurs mainly in young women and its main characteristic is the appearance of an abdominal mass which progressively increases in size. The radiologic, surgical and pathological correlation shows that it is a tumor of low grade malignancy with a favorable prognosis, after therapy and according to the location of the tumor. The authors report the clinical history of the first two confirmed cases of this entity in Panama, which occurred in 1985 and 1992, respectively, in women less than 25 years of age.

Adult↗

PubMed1994

[Internal carotid artery agenesis and multiple aneurysms in the posterior communicating artery].

Internal carotid artery agenesia is a rare anomaly of the embryonic development. We present a case with this anomaly and a vascular feeding of this territory out of the contralateral carotid system and the posterior vascular system. There were multiple aneurysms in the right posterior communicating artery, never described before in association with carotid agenesia, that are similar to the angiographic image of the fibromuscular dysplasia ("atypical" pattern). We review and discuss the embryonic development of this anomaly and its relationship with the hemodynamic stress and aneurysm formation.

Adult↗

PubMed1994

[Essential and symptomatic trigeminal neuralgia].

We present the principal differential characteristics of neuralgia of symptomatic and idiopathic trigeminus. Out of 39 consecutive patients with neuralgia of trigeminus evaluated clinically and with neuroimage study, we find recognizable pathology in 10 (3 arterio-venous malformations, 1 dolichoestasia of basilar artery, 3 tumors, 3 multiple sclerosis). Symptomatic neuralgia occurs in patients with lower average age and is accompanied by atypical symptoms or abnormal neurological signs and is no different from idiopathy as a response to pain from medical treatment. Painful affectation of the trigeminus requires the realization of complementary explorations aiming to dismiss associated neurological pathology.

Adult↗

PubMed1993

The amino acid sequence of Ole e I, the major allergen from olive tree (Olea europaea) pollen.

The complete primary structure of the major allergen from Olea europaea (olive tree) pollen, Ole e I (IUIS nomenclature), has been determined. The amino acid sequence was established by automated Edman degradation of the reduced and alkylated molecule as well as of selected fragments obtained by proteolytic digestions. Ole e I contains a single polypeptide chain of 145 amino acid residues with a calculated molecular mass of 16331 Da. No free sulfhydryl groups have been detected in the native protein. The molecule contains a putative glycosylation site. A high degree of microheterogeneity has been observed, mainly centered in the first 33% of the molecule. Comparison of Ole e I sequence with protein sequence databases showed no similarity with other known allergens. However, it has a 36% and 38% sequence identity with the putative polypeptide structures, deduced, respectively, from nucleotide sequences of genes isolated from tomato anthers and corn pollen, which have been suggested to be involved in the growing of the pollen tube. Therefore, the olive tree allergen may be a constitutive protein of the pollen involved in reproductive functions.

Allergens↗

PubMed1993

2,2-Dialkylnaphthalen-1-ones as new potassium channel activators.

A new series of 2,2-dialkylnaphthalen-1-one potassium channel activators has been prepared, and their in vitro relaxant activities in isolated rat portal vein and guinea pig tracheal spirals as well as their oral antihypertensive effect in spontaneously hypertensive rats have been evaluated. The group of 1,2-dihydro-4-(1,2-dihydro-2-oxo-1-pyridyl)-2,2-dimethylnaphthalen -1- ones with an electron-withdrawing substituent at the 6-position contain the most active compounds and 1,2-dihydro-4-(1,2-dihydro-2-oxo-1-pyridyl)-2,2-dimethyl-1-oxonaphtha lene-6- carbonitrile, 17f (UR-8225), has been selected for further pharmacological development.

Animals↗

PubMed1993

Cloning and expression of the major allergen from yellow mustard seeds, Sin a I.

The cloning and bacterial expression of the major allergen from yellow mustard (Sin a I) is reported. Cloning has been carried out by means of the polymerase chain reaction using non-degenerate oligo primers encoding the N- and C-terminal regions of the mature protein. Two nucleotide sequences (SA2S1 and SA2S2) have been found and analysed. The observed polymorphism suggests the existence of multiple isoforms for Sin a I allergen. SA2S2 has been expressed as a fusion protein, linked to the choline-binding domain of the Streptococcus pneumoniae murein hydrolase. The resulted fusion protein is recognized by Sin-a-I-specific antibodies.

Allergens↗

PubMed1993

DR7 and DQ2 are positively associated with immunoglobulin-E response to the main antigen of olive pollen (Ole e I) in allergic patients.

We have studied the relationship between HLA class II haplotypes and alleles, and the IgE antibody response to a highly purified allergen, Ole e I, in allergic patients. Ole e I, is the major antigen from the pollen of olive tree that grows mainly in the Mediterranean. Genomic DNA typing was performed in 40 unrelated patients with seasonal allergic pollenosis who had specific IgE antibodies against Ole e I, detected by double-antibody radioimmunoassay. HLA-DRB and -DQB loci were analyzed by PCR-SSO and RFLP. Phenotypic frequencies were compared with those of 179 healthy unrelated individuals. Significant increases in the phenotypic frequencies of DR7 (pf = 67.5% vs 31.3% in the control population, pc = 0.0023) and DQ2 (pf = 90.0% vs 48.0%, pc = 0.0003) were found, indicating an association between DRB1*0701/2, DQB1*0201 alleles and the IgE antibody response to Ole e I. This is the first time that the HLA-DQ gene has been associated with a positive allergic response.

Allergens↗