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Biomedical subjects

N Ortega

Publications and source records attributed to N Ortega.

At least 37 records · Page 2Linked to original sources
PubMed2001

[Spontaneous pneumothorax and active pulmonary tuberculosis].

We report three HIV-negative patients with spontaneous pneumothorax as clinical manifestation of active tuberculosis acute chest pain and dyspnea was the cause of admission. Chest roentgen grams showed lung collapse and parenchymal cavitation in two of therm and hydropneumothorax in the other. Outcome was favorable with antituberculous drug therapy and placement of chest tube. Although spontaneous pneumothorax is frequent in fibrosis pulmonary tuberculosis, it seldom complicated active tuberculosis in spite of increase of its incidence.

Adult↗
PubMed2000

Oral iron cutaneous adverse reaction and successful desensitization.

BACKGROUND: The oral administering of iron preparations sometimes produces adverse gastrointestinal effects. In contrast, cutaneous reactions are extremely rare. OBJECTIVE: We report a patient with several episodes of generalized pruritus and erythematous maculopapular eruption after receiving oral compounds of iron and on whom desensitization with oral iron was attempted. METHODS: We studied a female with microcytic anemia due to gynecologic blood loss who presented several episodes of cutaneous eruption after receiving oral compounds of iron. Skin prick-test and two simple-blind, placebo-controlled oral challenges were performed with various iron compounds, and finally desensitization with oral iron was carried out. RESULTS: Skin prick-test and patch-test with iron preparations were negative. Two simple-blind, placebo-controlled oral challenges were performed and the patient began experiencing similar cutaneous symptoms. We started a slow desensitization protocol using increasing doses until the target amount of the drug was tolerated without adverse effects. The chronic administration of oral iron therapy once a day for 9 months sustained the desensitized state and the anemia disappeared. CONCLUSION: We present methods to effectively manage iron supply for a microcytic anemia patient with cutaneous reactions due to oral iron compounds, to avoid repeated transfusions, slow desensitization with oral iron was successfully attempted.

Administration, Oral↗
PubMed2000

Characterization of the potato MADS-box gene STMADS16 and expression analysis in tobacco transgenic plants.

A new MADS-box gene, STMADS16, has been cloned in Solanum tuberosum L. that is expressed in all vegetative tissues of the plant, mainly in the stem, but not in flower organs. STMADS16 expression is established early during vegetative development and is not regulated by light. Sequence similarity besides the spatial and temporal expression patterns allow to define a novel MADS-box subfamily comprising STMADS16 and the gene STMADS11. Expression of the STMADS16 sense cDNA under the control of the 35S cauliflower mosaic virus promoter modifies the inflorescence structure by increasing both internode length and flower proliferation of the inflorescence meristems, and confers vegetative features to the flower. Moreover, STMADS16 ectopic expression overcomes the increase in flowering time and node number produced under short-day photoperiod, while the flowering time is not affected in long-day conditions. These results are discussed in terms of a possible role for STMADS16 in promoting vegetative development.

Amino Acid Sequence↗
PubMed1999

Signal relays in the VEGF system.

A considerable progress has been made during the past years in elucidating the molecular actors of angiogenesis. Vascular endothelial growth factor turned out to represent the major inducer of angiogenesis. Optional splicing of its pre messenger RNA generates various isoforms which differ not only by their storage in the extracellular matrix but also by their signaling pathways. VEGF binds and activates two tyrosine kinase receptors called VEGFR1 and VEGFR2 and neuropilin-1. The elucidation of the transduction pathways of each receptor suggests that VEGFR1 mediates cell migration whereas VEGFR2 mediates cell proliferation. The construction of internal images of VEGF by the anti-idiotypic antibody strategy allowed us to determine that quiescent endothelial cells need to be activated by so far unknown factors to become competent to respond to mitogenic signals and acquire an angiogenic phenotype. The discovery of the mechanisms of action of the VEGF system has allowed the design of promising drugs which already entered the pre-clinical or clinical assays.

Animals↗
PubMed1999

Association of HLA-DR11 with the anaphylactoid reaction caused by nonsteroidal anti-inflammatory drugs.

BACKGROUND: Several HLA alleles have been associated with asthma induced by nonsteroidal anti-inflammatory drugs (NSAIDs). The existence of HLA markers linked to other NSAID-induced reactions, such as cutaneous and anaphylactoid reactions, has not been established. OBJECTIVE: The purpose of our work was to study the HLA-DRB1 and HLA-DQB1 alleles in patients with cutaneous and anaphylactoid reactions caused by NSAIDs. METHODS: We have analyzed 114 HLA DRB1 and 26 HLA-DQB1 alleles in 21 patients with anaphylactoid reactions caused by NSAIDs, 47 patients who had exclusively cutaneous reactions during single-blind, placebo-controlled oral challenges with NSAIDs, and 167 tolerant control subjects (29 of whom had also had an IgE-mediated anaphylaxis to different agents). HLA-DRB1 and HLA-DQB1 alleles were typed by the polymerase chain reaction sequence-specific primers method with genomic DNA. RESULTS: The frequency of HLA-DR11 alleles was 58.8% in the anaphylactoid reaction group, compared with 15.9% in the NSAID-tolerant healthy control subjects (OR, 7:3; 95% confidence interval, 2.8-19.0; P <.02) and 6.3% in the group of the patients with a tolerance for NSAIDs and with IgE-mediated anaphylaxis (OR, 18.75; 95% confidence interval, 4.3-81.1; P <.004). No differences were observed among HLA-DR11 alleles analyzed. There were no significant HLA-DQB1 associations with NSAID-induced anaphylactoid reactions. Patients with cutaneous reactions had HLA frequencies that did not differ significantly from the tolerant control subjects. CONCLUSION: The HLA-DRB1*11 alleles showed a positive association with NSAID-induced anaphylactoid reactions.

Administration, Oral↗
PubMed1999

Class I chitinases as potential panallergens involved in the latex-fruit syndrome.

BACKGROUND: Latex-fruit cross-sensitization has been fully demonstrated. However, the antigens responsible for this "latex-fruit syndrome" have not been identified. We have recently shown that class I chitinases are relevant chestnut and avocado allergens. OBJECTIVE: We sought to evaluate the in vivo and in vitro reactions of purified chestnut and avocado chitinases in relation to the latex-fruit syndrome. METHODS: From a latex-allergic population, eighteen patients allergic to chestnut, avocado, or both were selected. Skin prick tests (SPTs) were performed with crude chestnut and avocado extracts, chitinase-enriched preparations, and purified class I and II chitinases from both fruits. CAP-inhibition assays with the crude extracts and purified proteins were carried out. Immunodetection with sera from patients with latex-fruit allergy and immunoblot inhibition tests with a latex extract were also performed. Eighteen subjects paired with our patients and 15 patients allergic to latex but not food were used as control groups. RESULTS: The chestnut class I chitinase elicited positive SPT responses in 13 of 18 patients with latex-fruit allergy (72%), and the avocado class I chitinase elicited positive responses in 12 of 18 (67%) similarly allergic patients. By contrast, class II enzymes without a hevein-like domain did not show SPT responses in the same patient group. Each isolated class I chitinase reached inhibition values higher than 85% in CAP inhibition assays against the corresponding food extract in solid phase. Immunodetection of the crude extracts and the purified class I chitinases revealed a single 32-kd band for both chestnut and avocado. Preincubation with a natural latex extract fully inhibited the IgE binding to the crude extracts, as well as to the purified chestnut and avocado class I chitinases. CONCLUSION: Chestnut and avocado class I chitinases with an N-terminal hevein-like domain are major allergens that cross-react with latex. Therefore they are probably the panallergens responsible for the latex-fruit syndrome.

Adolescent↗
PubMed1999

Tobacco allergy: demonstration of cross-reactivity with other members of Solanaceae family and mugwort pollen.

BACKGROUND: Tobacco is a plant belonging to the Solanaceae family. This plant is usually used as a contact insecticide for several infestations in some areas, such as the Canary Islands. Allergy induced by inhalation of this plant is unusual. Identification of the potential allergen in growing areas is essential. OBJECTIVE: We report a patient with occupational sensitivity to an aqueous solution of cut tobacco whose clinical manifestations were rhinoconjunctivitis and urticaria. Past medical history was significant for seasonal allergic rhinoconjunctivitis to mugwort pollen and oral allergy syndrome with avocado. METHODS: Green tobacco and cured tobacco leaf extracts were prepared, skin prick tests were performed with green tobacco, cured tobacco leaf extracts, and certain aeroallergens. Conjunctival challenge test was carried out with green tobacco and cured tobacco leaf extract. Serum-specific IgE against tobacco leaf was performed by commercial CAP. CAP inhibition experiments were carried out with tobacco and Artemisia vulgaris. RESULTS: Skin prick tests and conjunctival challenge tests with green tobacco and cured tobacco leaf extracts were positive, as well as serum-specific IgE by CAP, indicating an IgE-mediated sensitization. CAP inhibition experiments were carried out and it was found that tobacco, mugwort pollen, and tomato extracts inhibited the binding of the patient's serum to solid-phase tobacco leaf. No inhibition was observed when Alternaria, D. pteronyssinus, and potato were used as control inhibitors. Inhibition of immunoCAP to mugwort was obtained with mugwort and tobacco extracts and no cross-reactivity to D. pteronyssinus was shown. CONCLUSION: The results suggest that tobacco can induce IgE-mediated reactions that are mediated by the existence of common antigenic epitopes between tobacco and mugwort pollen. This allergy can be a hazard of employment in the agricultural areas.

Adult↗
PubMed1999

Occupational asthma in a grain worker due to Lepidoglyphus destructor, assessed by bronchial provocation test and induced sputum.

BACKGROUND: Occupational asthma (OA) can be a debilitating disease even when removal from the workplace is achieved. Today, the "gold standard" in the assessment of OA is the bronchial provocation test (BPT). Induced sputum is a non-invasive method of exploring airway inflammation which can provide additional information about such challenges and thus could be applied in OA diagnosis and monitoring. METHODS: We report the study carried out in a grain worker sensitized to Lepidoglyphus destructor (Ld), who suffered from mild asthma at the workplace. Skin prick test and specific serum IgE were measured. Ld-BPT was performed, and the changes in eosinophil rates, and ECP and tryptase levels in induced sputum were studied 30 min and 18 h after Ld-BPT. We also determined the changes in nonspecific bronchial hyperresponsiveness (NSBH), given as PD20 values. To assess the specificity of the changes, we also carried out sputum induction and methacholine challenge after barley-BPT. RESULTS: An isolated immediate response was obtained with Ld-BPT, while barley-BPT was negative. Induced sputum showed higher tryptase levels 30 min after Ld-BPT, and higher eosinophil and epithelial cell percentages and ECP levels 18 h after Ld-BPT. There was also a decrease in methacholine PD20 values after Ld-BPT. Those changes were not observed after barley-BPT. CONCLUSIONS: The study of eosinophilic and mast-cell markers in induced sputum provides additional knowledge about the inflammatory process occurring in the airways, suggesting that the study of induced sputum should be considered in the assessment of OA.

Adult↗
PubMed1998

Isolation and molecular characterization of a new vegetative MADS-box gene from Solanum tuberosum L.

A cDNA clone, STMADS11, encoding a new MADS-box protein was isolated from Solanum tuberosum L. (potato). Expression of STMADS11 was found in all vegetative organs of the plant, but not in floral tissues. The expression was also detected in all developmental stages, from tuber sprouts to mature plants, reaching a maximum in well-developed organs. However, the level of STMADS11 mRNA was low in tissues such as resting tuber or sprouts developed in the cold, where the metabolic activity is reduced. "In situ" hybridizations performed on leaf and stem sections showed that the STMADS11 transcript is mainly associated with vascular bundles. Cladistic analysis arising from amino acid sequence comparison revealed that STMADS11 shows the highest similarity to STMADS16, another vegetative MADS-box gene from potato, and to the previously reported "orphan" genes AGL15 and AGL17 from Arabidopsis thaliana. Possible implications of these data in relation to STMADS11 function are discussed.

Amino Acid Sequence↗
PubMed1998

Carica papaya pollen allergy.

BACKGROUND: Carica papaya (CP) trees are widely cultivated in tropical and subtropical areas; however, CP pollen allergy has not been previously described. OBJECTIVE: To study patients with CP pollen hypersensitivity. METHODS: A CP pollen extract was elaborated. Skin prick tests (SPTs) with this extract, as well as with commercial papaya fruit and papain extracts, were performed. Specific IgE levels to CP pollen, papaya fruit, and papain were determined. Specific conjunctival challenge tests to the CP pollen extract were also performed. RAST inhibition studies among CP pollen, papaya fruit, and papain were carried out. Twenty atopic patients were used as a control group for in vivo and in vitro tests. RESULTS: Six patients with clinical histories of seasonal rhinoconjunctivitis or bronchial asthma in relation to CP trees exposure, suggestive of IgE-mediated respiratory allergy, were studied. Commercial SPT and specific serum IgE to papaya fruit and papain were positive in our patients. An IgE-mediated hypersensitivity to a CP pollen extract was demonstrated in all patients, by means of SPTs, specific serum IgE determinations, and conjunctival challenge tests. Control atopic subjects showed negative SPTs, specific IgE, and conjunctival challenge tests to the CP pollen extract. On RAST inhibition studies using CP pollen extract in solid phase, a significant crossreactivity was found among CP pollen, papaya fruit, and papain. CONCLUSIONS: Our study suggests that papaya flower pollen is able to induce respiratory IgE-mediated allergy. The existence of common allergens among papaya flower pollen, papaya fruit, and papain has been demonstrated by RAST inhibition.

Adolescent↗
PubMed1998

Comparison of skin-prick test and specific serum IgE determination for the diagnosis of latex allergy.

BACKGROUND: Latex IgE-mediated hypersensitivity has been recognized as an international health problem. However, there is poor information on the efficiency of the diagnostic methods available. OBJECTIVE: The purpose of this study was to specify the efficiency of several diagnostic methods for latex allergy. METHODS: We designed a prospective study involving 50 adult patients with latex allergy, as diagnosed by a suggestive clinical history and a positive skin-prick test (SPT) to a latex extract. One control group of 50 subjects paired for age, sex, total IgE levels and latex exposure, and another control group of 30 subjects with pollen allergy were used. A low-ammoniated natural-latex and several glove-latex extracts were elaborated. SPTs with these extracts, as well as with four different commercial-latex extracts were performed. Latex-specific serum IgE was determined by the CAP and the AlaSTAT methods. RESULTS: Diagnostic sensitivity was 98% for the natural-latex extract SPT, from 90% to 98% for the commercial-latex extract SPT, and from 64% to 96% for the glove-latex extract SPT. Diagnostic specificity of SPT was 100%, and no severe adverse reactions were observed during skin testing. With respect to the latex-specific serum IgE determinations, sensitivity was 86% for the CAP system and 84% for the AlaSTAT assay, and specificity was dependent on the population considered. CONCLUSION: SPT with natural latex extracts has shown a diagnostic efficiency close to 100%, significantly higher than that of latex-specific serum IgE determination.

Adult↗
PubMed1997

Anaphylactoid reactions due to nonsteroidal antiinflammatory drugs: clinical and cross-reactivity studies.

BACKGROUND: Anaphylactoid reactions due to nonsteroidal antiinflammatory drugs have been described. OBJECTIVE: To study the clinical characteristics of 21 patients with anaphylactoid reactions due to nonsteroidal antiinflammatory drugs and to determine the cross-reactivity to non-steroidal antiinflammatory drugs not involved in the previous reactions nor structurally related by means of single-blind, placebo-controlled drug challenges. PATIENTS AND METHODS: Twenty-one patients who exhibited clinical evidence of anaphylactoid reactions after nonsteroidal antiinflammatory drugs were recruited for the study at the time of admission in Emergency Unit of our Hospital, Single-blind, placebo controlled oral challenges with nonsteroidal antiinflammatory drugs (except those reported by the patient as being responsible for the previous reaction), were performed in all patients. RESULTS: Fifteen patients were woman and six man, with a mean age of 35.7 years (range 18 to 62 years). Thirteen patients (60%) were normal subjects without concomitant diseases. No increase in frequency of atopy in comparison to the general population was observed. Pyrazole derivatives were the most common nonsteroidal antiinflammatory drugs involved (71.3%). A tolerance to drugs included in drug challenge protocol was noted in all patients. CONCLUSION: In our population, pyrazole derivatives were the most common nonsteroidal antiinflammatory drugs involved in anaphylactoid reactions. Most patients appeared to be otherwise normal subjects without concomitant disease and no cross-reactivity with other non-steroidal antiinflammatory drugs not involved in the anaphylactoid reaction nor structurally related was found.

Administration, Oral↗
PubMed1997

Cross-reactivity between IgE-binding proteins from Anisakis, German cockroach, and chironomids.

Anisakis simplex larvae parasitize animals used as seafood and can produce a specific immune response in man. The ingestion of seafood contaminated with stage three of A. simplex larvae can induce a specific IgE response with clinical symptoms, usually urticaria, even if the fish is cooked before ingestion and the invasive infestation power destroyed by heating. Our preliminary studies showed a strong association of A. simplex sensitization with Ascaris lumbricoides, Daphnia, chironomid spp., Atlantic shrimp (Pandalus borealis), and German cockroach (Blattella germanica). We conducted the cross-reactivity study with cockroach, a ubiquitous insect, and Chironomidae (red mosquito larvae), a work-related allergen, without any possibility of Anisakis contamination. Serum samples were collected from 60 pediatric patients, with serum specific IgE to A. simplex. Both specific-IgE and immunoblot-inhibition studies, with a serum pool from 18 patients, were performed to determine whether the association of sensitizations to nematodes and arthropods was due to immunologic cross-reactivity. In addition, serum samples from 21 of 60 patients who showed also sensitization to German cockroach were used for individual immunoblot studies. In the serum pool, dose-dependent inhibition of B. germanica and Chironomus spp, was observed after preincubation with the A. simplex extract. Immunoblot of Anisakis, inhibited with Chironomus and German cockroach, yielded a partial blot inhibition but mainly on bands below 41 kDa. Blot inhibition of German cockroach and Chironomus with Anisakis was dose related. The band patterns in individual blots were heterogeneous, but most of them had bands of 30-43 kDa. None of these sera recognized allergens in the 14-kDa area. In our study, CAP-inhibition and immunoblot-inhibition analysis of Anisakis showed that several IgE-binding components could be shared by the three allergens.

Allergens↗
PubMed1997

Vascular endothelial growth factor confers a growth advantage in vitro and in vivo to stromal cells cultured from neonatal hemangiomas.

Neonatal hemangioma is a common benign proliferation of unorganized structures containing stromal and capillary endothelial cells. We tested the hypothesis that such cell proliferation might result from the release by stromal cells of endothelial cell mitogens. Stromal cells cultured from biopsies of surgically removed life-threatening hemangiomas released an endothelial cell mitogen in vitro that was indistinguishable from vascular endothelial growth factor (VEGF) based on independent criteria such as affinity chromatography for heparin or anti-VEGF IgG and radioreceptor assay. A functional product of the KDR gene encoding a cognate VEGF receptor was also expressed by these stromal cells. Transient transfection with antisense oligonucleotides targeted on the translation initiation codon of KDR abolished its tyrosine phosphorylation and mitogenic response of neonatal hemangioma cells to VEGF, confirming the existence of an autocrine loop of proliferation. When grafted in nude mice, these stromal cells elicited an angiogenic response that was blocked by neutralizing anti-VEGF IgG. These results might provide a clue to the importance of stromal cells in the pathogeny of neonatal hemangiomas.

Animals↗
PubMed1996

A behavioural preparation for the study of human Pavlovian conditioning.

Conditioned suppression is a useful technique for assessing whether subjects have learned a CS-US association, but it is difficult to use in humans because of the need for an aversive US. The purpose of this research was to develop a non-aversive procedure that would produce suppression. Subjects learned to press the space bar of a computer as part of a video game, but they had to stop pressing whenever a visual US appeared, or they would lose points. In Experiment 1, we used an A+/B- discrimination design: The US always followed Stimulus A and never followed Stimulus B. Although no information about the existence of CSs was given to the subjects, suppression ratio results showed a discrimination learning curve-that is, subjects learned to suppress responding in anticipation of the US when Stimulus A was present but not during the presentations of Stimulus B. Experiment 2 explored the potential of this preparation by using two different instruction sets and assessing post-experimental judgements of CS A and CS B in addition to suppression ratios. The results of these experiments suggest that conditioned suppression can be reliably and conveniently used in the human laboratory, providing a bridge between experiments on animal conditioning and experiments on human judgements of causality.

Animals↗
PubMed1996

Vascular endothelial growth factor and retinal neovascularisation: a new therapeutic approach for diabetic retinopathy.

Since the pioneer work of Michaelson in 1947 reporting that retinal ischemia induces the release of soluble angiogenic compounds, numerous studies have been conducted to identify the molecular structure of such messengers. In the early 1980s, the deciphering of angiogenic factor-signaling pathways and their description in the retina focused attention on growth factors. Vascular endothelial growth factor, the major candidate identified in 1992, induces in vivo angiogenesis and vascular permeability. Its expression is enhanced in vitro by hypoxia and hypoglycaemia; and its immunoreactivity is increased in diabetic patients. A decrease in its bioavailability reduces the intensity of neovascularization.

Animals↗
PubMed1988

Corticotropin-induced changes in enzymatic activities of the post-pregnenolone steroidogenic pathway in rabbit adrenocortical cells.

In an attempt to delineate the effect of corticotropin (ACTH) on post-pregnenolone steroidogenesis, the activity of enzymatic systems operative in conversion of pregnenolone into glucocorticoids and androgens was studied in adrenocortical cells from control rabbits and from animals treated with ACTH for 12 days (ACTH 1-24, 200 micrograms s.c. daily). The cells from ACTH-treated rabbits exhibited an increased overall steroidogenic capacity and produced much more cortisol (P less than 0.0005) as well as other 17-hydroxylated steroids as a result of increased activity of 17 alpha-hydroxylase; corticosterone generation was concomitantly reduced. The increased conversion of pregnenolone or progesterone into androgens, as a result of previous treatment with ACTH, provides additional evidence for an effect of ACTH on 17 alpha-hydroxylase activity. A stimulatory effect of ACTH on 11 beta-hydroxylase was also evidenced by these cells, since conversion of 11-deoxycortisol into cortisol was enhanced (P less than 0.005). The increased production of androgens from 17-hydroxylated precursors by cells from ACTH-treated rabbits suggests that ACTH also exerts a prolonged stimulatory effect on 17,20-lyase. The activity of 3 beta-hydroxysteroid dehydrogenase-isomerase was apparently not influenced by chronic treatment with ACTH, judged from unchanged conversion of dehydroepiandrosterone into androstenedione. The activity of 11 beta-dehydrogenase was likewise unchanged in these conditions.

Adrenal Cortex↗