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Biomedical subjects

C Blanco

Publications and source records attributed to C Blanco.

At least 73 records · Page 4Linked to original sources
PubMed1999

Cross-reactions in the latex-fruit syndrome: A relevant role of chitinases but not of complex asparagine-linked glycans.

BACKGROUND: Cross-reactions between latex and plant foods (mainly fruits) have been widely reported. Although the cross-reactive components have not been well identified, class I chitinases seem to be the most credible candidates in chestnut, avocado, and banana. OBJECTIVE: We sought to evaluate the potential role of chitinases and complex glycans as cross-reactive determinants linked to latex-food allergy. METHODS: Extracts from 20 different plant foods and from latex were obtained. These preparations were immunodetected with anticomplex glycans and antichitinase sera raised in rabbits, as well as with sera from patients with latex-fruit allergy and sera from patients allergic to latex without food allergy. Immunoblot inhibition assays were carried out by using a purified class I chitinase from avocado or latex extract as inhibitors. RESULTS: Reactive proteins of approximately 30 to 45 kd (putative class I chitinases) were recognized by both specific polyclonal antibodies to chitinases and sera from patients with latex-fruit allergy in chestnut, cherimoya, passion fruit, kiwi, papaya, mango, tomato, and flour wheat extracts. Prs a 1, the major allergen and class I chitinase from avocado, and the latex extract strongly or fully inhibited IgE binding by these components when tested in immunoblot inhibition assays. Additional bands of 16 to 20 kd, 23 to 28 kd, and 50 to 70 kd were detected by the antichitinase serum but not with the patients' pooled sera. The putative 30- to 45-kd chitinases present in different food extracts did not react with a pool of sera from subjects allergic to latex but not to fruit. Very different immunodetection patterns were produced with the anticomplex glycan serum and the sera from allergic patients. CONCLUSIONS: Putative class I chitinases seem to be relevant cross-reactive components in foods associated with the latex-fruit syndrome, but do not play a specific role in allergy to latex but not to fruit. Cross-reactive carbohydrate determinants are not important structures in the context of latex-fruit cross-sensitization.

Animals↗
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

Linkage of house dust mite allergy with the HLA region.

BACKGROUND: Atopy is a multifactorial disease, the pathogenesis of which is influenced by both genetic and environmental conditions. Genes in the HLA region have been involved in the control of the IgE response. OBJECTIVE: In order to investigate whether allergy to house dust mite is associated with HLA in our population, we performed sib-pair analysis in 18 families and a case/control study of 161 non-related individuals. METHODS: Levels of total and specific IgE were determined, skin-prick tests were carried out and clinical history was reviewed for every subject in the study. HLA class II typing was performed by the polymerase chain reaction with sequence specific primers. RESULTS: We observed a significant difference from expected values in haplotypes shared by affected sibs; however, the case/control study did not reveal any association with any particular allele. CONCLUSION: These results suggest that any particular HLA-DRB1/DQA1/DQB1 allele is responsible for the development of allergy to house dust mite in the Spanish population. Some other locus in or close to the HLA region might be involved, e.g., the tumour necrosis factor gene, a possibility that would explain the significant difference from expected values in the segregation of HLA haplotypes.

Adolescent↗
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↗
PubMed1999

Isolation and characterization of major banana allergens: identification as fruit class I chitinases.

BACKGROUND: Banana allergy has been associated with the latex-fruit syndrome. Several IgE-binding components, the relevant ones being proteins of 30-37-kDa, have been detected in banana fruit, but none of them have been isolated and characterized yet. Objective To purify and characterize the 30-37 kDa banana allergens. METHODS: Fifteen patients allergic to banana were selected on the grounds of a latex-allergic population. Prick by prick tests to this fruit were performed. Total and specific IgE to banana were determined. Banana allergens were isolated by affinity chromatography, followed by cation-exchange chromatography. Their characterization includes N-terminal sequencing, enzymatic activity assays, immunodetection with sera from allergic patients and with antichitinase antibodies, and CAP and immunoblot inhibition tests. Skin prick tests with banana extracts and with the purified allergens were also carried out. RESULTS: Two major IgE-binding proteins of 34 and 32 kDa, also recognized by polyclonal antibodies against chestnut chitinases, were immunodetected in crude banana extracts. Purification and characterization of both proteins have allowed their identification as class I chitinases with an hevein-like domain. Each isolated allergen reached inhibition values higher than 90% in CAP inhibition assays, and fully inhibited the IgE-binding by the crude banana extract when tested by an immunoblot inhibition method. The two purified allergens provoked positive skin prick test responses in more than 50% of the banana-allergic patients. CONCLUSIONS: Class I chitinases with an hevein-like domain are major allergens in banana fruit. Their presence in other fruits and nuts, such as avocado and chestnut, could explain the cross-sensitization among these foods.

Adolescent↗
PubMed1999

Microstructure and properties of pitch-based carbon composites

Pitches prepared in the laboratory by thermal treatment and air-blowing of a commercial coal-tar pitch were used as matrix precursors of carbon composites using granular petroleum coke, foundry coke, amorphous graphite and anthracite. Pitches were characterized by standard procedures (elemental analysis, softening point, solubility tests and carbon yield) and light microscopy (mesophase content). Pitch pyrolysis behaviour was monitored by thermogravimetric analysis and from the optical texture of cokes. Pitch wettability to the different carbons, at different temperatures, was also studied. Experimental conditions selected for the preparation of composites were based on pitch composition and properties. The main microstructural features of composites were determined by light microscopy and scanning electron microscopy. Composite properties were described in terms of their density, porosity and compressive strength, and related to composite microstructure and the characteristics of the precursors. Thermal treatment and air-blowing of pitch improved carbon composite structure and properties. The lowest porosities and best mechanical properties were observed in those composites obtained with the thermally treated pitches combined with foundry coke and anthracite.

Journal Article↗
PubMed1999

Disaccharides as a new class of nonaccumulated osmoprotectants for Sinorhizobium meliloti.

Sucrose and ectoine (1,4,5,6-tetrahydro-2-methyl-4-pyrimidine carboxylic acid) are very unusual osmoprotectants for Sinorhizobium meliloti because these compounds, unlike other bacterial osmoprotectants, do not accumulate as cytosolic osmolytes in salt-stressed S. meliloti cells. Here, we show that, in fact, sucrose and ectoine belong to a new family of nonaccumulated sinorhizobial osmoprotectants which also comprises the following six disaccharides: trehalose, maltose, cellobiose, gentiobiose, turanose, and palatinose. Also, several of these disaccharides were very effective exogenous osmoprotectants for strains of Rhizobium leguminosarum biovars phaseoli and trifolii. Sucrose and trehalose are synthesized as endogenous osmolytes in various bacteria, but the other five disaccharides had never been implicated before in osmoregulation in any organism. All of the disaccharides that acted as powerful osmoprotectants in S. meliloti and R. leguminosarum also acted as very effective competitors of [14C]sucrose uptake in salt-stressed cultures of these bacteria. Conversely, disaccharides that were not osmoprotective for S. meliloti and R. leguminosarum did not inhibit sucrose uptake in these bacteria. Hence, disaccharide osmoprotectants apparently shared the same uptake routes in these bacteria. Natural-abundance 13C nuclear magnetic resonance spectroscopy and quantification of cytosolic solutes demonstrated that the novel disaccharide osmoprotectants were not accumulated to osmotically significant levels in salt-stressed S. meliloti cells; rather, these compounds, like sucrose and ectoine, were catabolized during early exponential growth, and contributed indirectly to enhance the cytosolic levels of two endogenously synthesized osmolytes, glutamate and the dipeptide N-acetylglutaminylglutamine amide. The ecological implication of the use of these disaccharides as osmoprotectants is discussed.

Amino Acids, Diamino↗
PubMed1999

Practice patterns of international and U.S. medical graduate psychiatrists.

OBJECTIVE: The practice patterns of international medical graduate (IMG) and U.S. medical graduate (USMG) psychiatrists were compared. METHOD: Using data from the 1996 National Survey of Psychiatric Practice, the authors compared IMGs and USMGs in terms of demographic characteristics, practice settings, patients' clinical characteristics, and sources of reimbursement. RESULTS: The IMGs surveyed tended to be older than USMGs, included a higher proportion of women, and were more racially heterogeneous. They worked longer hours, worked more frequently in the public sector, and treated a higher proportion of patients with psychotic disorders. The IMGs also received a higher percentage of their income than USMGs from Medicaid and Medicare, whereas the reverse was true of self-payment. Most of these differences remained significant after psychiatrist's age, gender, race, board certification, and work setting were controlled for. CONCLUSIONS: IMG and USMG psychiatrists have different practice patterns. Policies that substantially decrease the number of IMG psychiatrists may adversely affect the availability of psychiatrists to treat minorities and other underserved populations.

Adult↗
PubMed1998

Class I chitinases with hevein-like domain, but not class II enzymes, are relevant chestnut and avocado allergens.

BACKGROUND: Several foods associated with the latex-fruit syndrome present relevant allergens of around 30 kd. Neither these components nor any other responsible for the reported cross-reactions have been identified and purified. OBJECTIVE: We sought to isolate and characterize the 30 kd allergens from avocado fruit and chestnut seed, two of the main allergenic foods linked with latex allergy. METHODS: Sera from patients allergic to chestnut and avocado were selected according to clinical symptoms, specific IgE levels, and positive skin prick test responses. Class I and II chitinases were purified by affinity and cation-exchange chromatography and characterized by specific IgE and anti-chitinase immunodetection, immunoblot inhibition assays, enzymatic activity tests, and N-terminal sequencing. RESULTS: Relevant 32 kd allergens were detected by specific IgE immunodetection in both avocado and chestnut crude extracts. The same bands, together with others of 25 kd, were revealed by a monospecific antiserum against class II chitinases. Purification and characterization of the 32 kd allergens from both plant sources allowed their identification as class I chitinases with an N-terminal hevein-domain. The purified allergens fully inhibited IgE binding by the corresponding crude extract when tested in immunoblot inhibition assays. Highly related 25 kd class II chitinases that lack the hevein-like domain were also isolated from the same protein preparations. No IgE-binding capacity was shown by these class II enzymes. CONCLUSION: Class I chitinases are relevant allergens of avocado and chestnut and could be the panallergens responsible for the latex-fruit syndrome. The hevein-like domain seems to be involved in their allergenic reactivity.

Adult↗
PubMed1998

Cloning and sequence determination of a phi AAU2 gene whose product aborts the phage lytic cycle.

This communication describes the cloning of a 1.8-kb fragment from the genome of the corynephage phi AAU2, which aborts the phage lytic cycle when cloned on a high-copy shuttle vector. The associated phenotype, called Apld (aborting phage lytic development), was revealed by noting the reduced plaque size and lower efficiencies of plaquing of phi AAU2 cp, a virulent derivative of phi AAU2, on "Arthrobacter aureus"-C70 Apld+ cells. Adsorption and phage DNA transfection experiments showed evidence that Apld acted once the phage DNA had entered into the cell; apld was confined to a single open reading frame (ORF), encoding a putative 63-aa polypeptide which did not show any homology to proteins contained in the databanks; apld is followed by an ORF the product of which shows homology with a protein expressed by the early region of the Streptomyces phage phi C31.

Amino Acid Sequence↗
PubMed1998

Carnitine acts as a compatible solute in Brevibacterium linens.

Carnitine is a trimethyl amino acid found at relatively high concentrations in materials of animal origin. Exogenously provided L-carnitine was found to stimulate growth of Brevibacterium linens ATCC 19391 in media with inhibitory osmotic strength. Its osmoprotective ability was as potent as that of glycine betaine. Electrophoretic and spectroscopic (NMR) analysis showed that this compound is only transiently accumulated, but in significant amounts, by B. linens under hyperosmotic stress and is converted into glycine betaine. The L-carnitine/glycine betaine pathway is inducible by L-carnitine in B. linens. The D-enantiomer did not improve growth of B. linens, even though this solute is accumulated by B. linens at the same level as glycine betaine. The two isomeric forms of carnitine repress the build-up of ectoine, the main endogenous osmolyte in B. linens.

Amino Acids, Diamino↗
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↗
PubMed1998

Differential Effects of Dimethylsulfoniopropionate, Dimethylsulfonioacetate, and Other S-Methylated Compounds on the Growth of Sinorhizobium meliloti at Low and High Osmolarities.

An extract from the marine alga Ulva lactuca was highly osmoprotective in salt-stressed cultures of Sinorhizobium meliloti 102F34. This beneficial activity was due to algal 3-dimethylsulfoniopropionate (DMSP), which was accumulated as a dominant compatible solute and strongly reduced the accumulation of endogenous osmolytes in stressed cells. Synthetic DMSP also acted as a powerful osmoprotectant and was accumulated as a nonmetabolizable cytosolic osmolyte (up to a concentration of 1,400 nmol/mg of protein) throughout the growth cycles of the stressed cultures. In contrast, 2-dimethylsulfonioacetate (DMSA), the sulfonium analog of the universal osmoprotectant glycine betaine (GB), was highly toxic to unstressed cells and was not osmoprotective in stressed cells of wild-type strains of S. meliloti. Nonetheless, the transport and accumulation of DMSA, like the transport and accumulation of DMSP and GB, were osmoregulated and increased fourfold in stressed cells of strain 102F34. Strikingly, DMSA was not toxic and became highly osmoprotective in mutants that are impaired in their ability to demethylate GB and DMSA. Furthermore, 2-methylthioacetate and thioglycolic acid (TGA), the demethylation products of DMSA, were excreted, apparently as a mechanism of cellular detoxification. Also, exogenous TGA and DMSA displayed similar inhibitory effects in strain 102F34. Thus, on the basis of these findings and other physiological and biochemical evidence, we infer that the toxicity of DMSA in wild-type strains of S. meliloti stems from its catabolism via the GB demethylation pathway. This is the first report describing the toxicity of DMSA in any organism and a metabolically stable osmoprotectant (DMSP) in S. meliloti.

Journal Article↗
PubMed1998

Sucrose is a nonaccumulated osmoprotectant in Sinorhizobium meliloti.

Intracellular accumulation of sucrose in response to lowered water activity seems to occur only in photosynthetic organisms. Here we demonstrate, for the first time, the potent ability of this common sugar, supplied exogenously, to reduce growth inhibition of Sinorhizobium meliloti cells in media of inhibitory osmolarity. Independently of the nature of the growth substrates and the osmotic agent, sucrose appears particularly efficient in promoting the recovery of cytoplasmic volume after plasmolysis. Surprisingly, sucrose is not accumulated by the bacteria at an osmotically efficient level. Instead, it strongly stimulates the accumulation of the main endogenous osmolytes glutamate and N-acetylglutaminylglutamine amide (NAGGN). Examining cell volume changes during the hyperosmotic treatment, we found a close correlation between the enhancement of the osmotically active solute pool and the increase in cell volume. Sucrose shares several features with ectoine, another nonaccumulated osmoprotectant for S. meliloti. Overall, osmoregulation in S. meliloti appears to be strongly divergent from that in most bacteria.

Betaine↗