Cross-reacting allergens in natural rubber latex and avocado

Although phencyclidine (PCP) has several neurochemical effects, the most pharmacologically relevant are thought to be its ability to antagonize the activity of N-methyl-D-aspartate (NMDA)-type glutamate receptors and to increase extracellular dopamine concentrations. In order to elucidate the nature and consequence of PCP actions on glutamatergic and dopaminergic pathways, this study examined the response of extrapyramidal and limbic neurotensin systems to this drug. Multiple, but not single, doses of PCP caused increases in striatal neurotensin-like immunoreactivity content of 150-200% of control. These effects were blocked by the dopamine D1 receptor antagonist, SCH 23390, suggesting they were caused by PCP-mediated enhanced dopamine activity at dopamine D1 receptors. In contrast, MK-801 (dizocilpine), a selective NMDA receptor antagonist that acts at the same site as PCP, had no effect on neurotensin-like immunoreactivity content when given alone. In addition, coadministration of MK-801 with PCP did not alter the effect of PCP on striatal neurotensin-like immunoreactivity content. This lack of effect suggests that the actions of PCP on NMDA receptors was not involved in the neurotensin response. The PCP effect on neurotensin striatal pathways also appeared not to be associated with the dopamine D2 or gamma-aminobutyric acid (GABA) systems: a possible role for the sigma receptor in this effect could not be eliminated. Administration of multiple doses of PCP also affected neurotensin-like immunoreactivity content in the nucleus accumbens (160% compared to control) and frontal cortex (40% compared to control), but not the substantia nigra. The neurotensin effects of PCP are compared to those of another psychotomimetic drug of abuse, methamphetamine.     

Immunoaffinity analysis of cross-reacting allergens by protein blotting

IgE antibodies from sera having reactivity against ryegrass pollen protein allergens, wheat endosperm protein allergens and also several other cereal protein allergens were adsorbed with either ryegrass pollen or the wheat/globulin fraction immobilised on solid phases and subsequently eluted with low pH buffer. The eluted antibodies were reacted with sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) blots of the different allergens. Antibodies adsorbed and subsequently eluted from the two allergen sources recognised different spectra of proteins in the ryegrass pollen and cereal allergen sources and indicated the degree of immunological cross-reactivity. Intra-species cross-reactivity of IgE antibodies was demonstrated employing similar methods to those used for the pollen and cereal allergens by using a recombinant allergen from the venom of the ant Myrmecia pilosula as the immunoadsorbent protein on the solid phase.     

Cloning, expression and characterization of the major latex allergen prohevein

BACKGROUND: About 70-80% of latex allergic health care workers are sensitized to prohevein (Hev b 6.01), a 20 kDa cysteine-rich chitin-binding protein of Hevea latex. OBJECTIVE: This study reports on the bacterial cloning, expression and immunochemical characterization of rHev b 6.01. METHODS: Prohevein was expressed in the periplasmatic space of Escherichia coli as maltose binding protein (MBP) fusion protein and purified to homogeneity after factor Xa cleavage. The IgE binding capacity of both rHev b 6.01 and prohevein isolated from fresh Hevea latex was compared by immunoblotting experiments using sera of latex-allergic patients. The diagnostic value of rHev b 6.01 was analysed by enzyme allergosorbent test (EAST). RESULTS: Two different cDNA clones of rHev b 6.01 were established. The deduced amino acid sequence of both clones revealed two and three amino acid differences in the C-terminal domain of prohevein compared with the original database entry. Purified rHev b 6.01 bound with high affinity to chitin as its natural counterpart isolated from natural latex. In IgE-immunblotting using sera of affected subjects binding intensity to both proteins was comparable indicating a very high antigenic similarity. The diagnostic value of MBP-prohevein was tested in EAST using sera of 33 latex-allergic subjects. The in vitro test showed high sensitivity and specificity and proved the diagnostic value of uncleaved MBP-prohevein. CONCLUSIONS: The production of recombinant latex key allergens with defined quality like prohevein is a straightforward strategy for the development of standardized in vitro test systems.     

Determination of pesticide residues in fruit and vegetables

A review concerning the determination of pesticide residues in fruit and vegetables is presented. The basic principles and recent developments in the extraction and quantitation of pesticides are discussed. Consideration is given to solid phase and supercritical extraction techniques, automation and robotic systems, and immunoassay procedures.     

Ubiquitous structures responsible for IgE cross-reactivity between tomato fruit and grass pollen allergens

The simultaneous presence of IgE reactivity to tomato fruit and grass pollen allergens is evident in many patients with allergy and may be caused by cross-reactivity. Using sera from polysensitized patients with a positive enzyme allergosorbent test (EAST) result (score > 2), we tested reactivity to both allergen sources. IgE reactivity against both extracts was demonstrated in eight serum samples, and cross-reactivity was confirmed by the EAST inhibition assay. The structures responsible for this cross-reactivity were identified by Western blotting: five of the eight sera demonstrated a 16 kd protein in both extracts, which was identified as profilin. Additionally, seven of the eight sera showed IgE binding to epitopes on carbohydrate moieties, which contained alpha 1, 3 fucosylations. To determine the allergens of tomato fruit extract, we performed two-dimensional polyacrylamide gel electrophoresis blotting. We were able to demonstrate one highly concentrated and about 20 weaker proteins possessing terminal fucose residues. These are similarly found in grass pollen extracts. It is therefore postulated that the cross-reactivity is affected by profilins and similar carbohydrate determinants. If carbohydrate structures can provoke IgE cross-reactivity between phylogenetically distant species, such structures may play an important role in sensitization and mediator release. The ubiquitous nature of the IgE-binding determinants was studied by additional EAST inhibition tests with tomato allergen disks and extract from birch pollen, mugwort pollen, apple, and celery, leading to significant inhibitions among all these allergen sources. Epitopes exclusive to grass pollen and tomato have not been detected.     

Common allergenic structures in hazelnut, rye grain, sesame seeds, kiwi, and poppy seeds

Allergy to kiwi, poppy seeds, and/or sesame seeds often occurs in patients with a simultaneous sensitization to nuts and flour. Previously cross reactions have been verified by RAST inhibition. In this study the nature of this cross-reactivity is further characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), followed by immunoblotting to nitrocellulose. The degree of cross-reactivity among kiwi, sesame seeds, poppy seeds, hazelnuts, and rye grain was found to be very high in the patients studied. The existence of both cross-reacting and unique components was observed; however, the cross-reacting and unique components could be different for different patients.     

Guanine, mite, and cockroach allergens in Costa Rican homes

In the carbohydrate deficient glycoprotein syndrome (CDGS) type 1 glycoproteins with less and shorter N-linked oligosaccharides are synthesized due to a deficiency of phosphomannomutase. Glucose deprivation or mannose addition are shown to partially or fully correct the size of oligosaccharides incorporated into lipid linked oligosaccharides and nascent glycoproteins in skin fibroblasts from CDGS type 1 patients with a phosphomannomutase defect. The corrective effect is ascribed to regulatory mechanisms and/or metabolic pathways that bypass phosphomannomutase.     

Comparison of hydrophilic polymer-coated latex, uncoated latex and PVC indwelling balloon catheters in the prevention of urinary infection

Latex, hydrophilic polymer-coated latex and PVC balloon indwelling urethral catheters were compared in respect of the urinary tract infections arising in association with their use in male patients. The polymer (Hydron) coating conferred no benefit over uncoated latex which in turn was indistinguishable from PVC. No significant differences in the spectra of infecting organismns were observed between the 3 catheter types.     

Purification and characterization of a highly stable cysteine protease from the latex of Ervatamia coronaria

A highly stable cysteine protease was purified to homogeneity from the latex of Ervatamia coronaria by a simple purification procedure involving ammonium sulfate precipitation and ion-exchange chromatography. The molecular mass was estimated to be approximately 25,000 Da by SDS-PAGE and gel filtration. The extinction coefficient (epsilon 280 nm 1%) of the enzyme was 24.6. The enzyme hydrolyzed denatured natural substrates like casein, hemoglobin, azoalbumin, and azocasein with a high specific activity but showed low specific activity towards synthetic substrates. The pH and temperature optima were 7.5-8.0 and 50 degrees C respectively. The activity of the enzyme was strongly inhibited by thiol-specific inhibitors like leupeptin, iodoacetamide, PCMB, NEM, and mercuric chloride. The striking property of this enzyme was its stability over a wide pH range (2-12) and other extreme conditions of temperature, denaturants, and organic solvents. The N-terminal sequence showed marked similarity to known cysteine proteases.     

消解氨溶-火焰原子吸收光谱法测定胶乳中钠

用消解氨溶法处理胶乳样品 ,即先用浓硝酸消解样品 ,再用氨水溶解消解产物 ,建立了在氨性溶液中快速测定胶乳中钠的FAAS法。以硝酸钾溶液作为消电离剂 ,用工作曲线法测定。对样品处理方法、消解产物的溶解性质、线性范围、干扰及检出限进行了考察。测定结果的相对标准偏差 1.7% ,加标回收率 97.3 %～ 10 2.3 %。方法简便、快速、准确。     

Identification of Cannabis pollens using an allergic patient's immunoglobulin E and purification and characterization of allergens in Cannabis pollens

Cannabis pollen allergens were detected using the serum of an allergic patient. The allergens were then purified by sequential column chromatography (including DE52 cellulose and phenyl-Sepharose CL-4B) and preparative HPLC. The molecular weight of the allergens were determined as 10,050 and 13,706 by matrix-assisted laser desorption/ionization time of flight mass spectrometry. We utilised Western blotting and development of an enzyme-linked immunosorbent assay for the detection of Cannabis pollen allergens.     

Presence of cross-reacting thymus and brain antigens in the cerebral cortex

Rabbit antisera against antigens of mouse, rabbit, guinea pig and human whole brain cross-reacted in the cytotoxic test with the lymphocytes of the thymus, lymph nodes and the spleen of these animal species. Mouse thymocytes were most sensitive to the antibrain sera (cytotoxic index -- 63--100 per cent); cells from other mouse lymphoid organs and lymphocytes of rabbit, guinea pig and man were more resistant. Bone marrow lymphocytes were not damaged by any of these sera. The antigens which induced the cytotoxic properties of the sera were found only in the human cerebral cortex, but not in the white matter of the brain stem.     

Characterization of allergens in Apiaceae spices: anise, fennel, coriander and cumin

BACKGROUND: Symptoms elicited by IgE-mediated food allergy range from mild local to severe systemic reactions. Allergens in spices are particularly dangerous due to their hidden presence in many dishes. OBJECTIVES AND METHODS: According to clinical observations, mugwort and birch pollen allergy, and hypersensitivity to spices are frequently associated, but the crossreacting compounds were not defined so far. We tested sera of 15 patients who experienced adverse reactions to spiced food and characterized their IgE-binding patterns on anise, fennel, coriander and cumin extracts through immunoblot and inhibition experiments. RESULTS: The use of anti-Bet v 1 (MoAb) and anti-profilin (rabbit) antibodies revealed the presence of crossreacting allergens in the tested spice extracts. Inhibition experiments showed that IgE-binding to allergens in Apiaceae spices could be blocked by preincubation of sera with rBet v 1 or rBet v 2 (birch profilin). Moreover, we detected crossreacting allergenic molecules in the molecular weight range of 60 kDa. IgE-binding to spice allergens occurred only with sera of 10/15 (66%) patients with allergy to pollen (birch, mugwort) and/or celeriac. In five out of 15 (33%) patients with a history of adverse reaction to spices, but without pollen and celeriac allergy, no IgE-binding to any spice protein could be demonstrated. It is possible that these clinical reactions could be elicited by other types of hypersensitivity (Type II, III, IV), however, as spices contain highly reactive substances, the symptoms may most likely be classified as food-intolerant. CONCLUSIONS: Bet v 1- and profilin-related allergens may, besides higher molecular weight allergenic molecules, be responsible for Type I allergy to anise, fennel, coriander or cumin, members of the Apiaceae.     

Role of nonspecific cross-reacting antigen, a CD66 cluster antigen, in activation of human granulocytes

Nonspecific cross-reacting antigen (NCA) is the name of a family of highly glycosylated bacterial-binding receptors found on human granulocytes and other tissues. These glycoproteins are members of the immunoglobulin supergene family and are related structurally to carcinoembryonic antigen. In this study, we demonstrate that ligation of granulocyte NCA results in the activation of the cells, as measured by degranulation and the flux of intracellular calcium. These studies further the proposition that NCA has a function in the immune response of granulocytes against bacterial infections.     

The major dog allergens, Can f 1 and Can f 2, are salivary lipocalin proteins: cloning and immunological characterization of the recombinant forms

Canis familiaris allergen 1 (Can f 1) and Canis familiaris allergen 2 (Can f 2) are the two major allergens present in dog dander extracts. We now report the isolation of cDNAs encoding both proteins and present their nucleotide and deduced amino acid sequences. Can f 1, produced by tongue epithelial tissue, has homology with the von Ebner's gland (VEG) protein, a salivary protein not previously thought to have allergenic properties. Can f 2, produced by tongue and parotid gland, has homology with mouse urinary protein (MUP), a known allergen. Both VEG protein and MUP are members of the lipocalin family of small ligand-binding proteins. Recombinant forms of Can f 1 and Can f 2 were produced and tested for immunoglobulin E (IgE) reactivity. Among dog-allergic subjects, 45% had IgE directed exclusively to rCan f 1, and 25% had IgE to both rCan f 1 and rCan f 2. In addition, both recombinant proteins were able to cross-link IgE and elicit histamine release from peripheral blood leucocytes in vitro. These findings confirm that Can f 1 and Can f 2 are major and minor dog allergens, respectively, and demonstrate that recombinant forms of dog allergens retain at least some IgE-binding epitopes.     

低合金钢中非金属夹杂物的检测与表征

低合金钢中非金属夹杂物的检测与表征, 需要解决夹杂物分析的代表性和准确性问题。实验以脉冲分辨分析方法确定了低合金钢中非金属夹杂物的组分, 并研究了其单火花脉冲分布和图谱。采用定量金相、扫描电镜和能谱仪等多种物理分析手段对目标夹杂物进行全面分析, 探讨了夹杂物的主要存在状态和异常光谱信号与夹杂物的颗粒数量、尺寸之间的相关性。研究发现单位面积内夹杂物的尺寸越大, 对异常火花相对频数和异常平均强度占总体平均强度的比例影响越大。在对低合金钢进行常量元素含量检测的同时, 通过单火花脉冲分布和图谱还能对非金属夹杂物进行识别和检测, 结合金相和扫描电镜物理分析手段实现了非金属夹杂物的定量和定性, 适用于对低合金钢的日常质量控制。     

The effect of dry heat on mite, cat, and dog allergens

BACKGROUND: Various techniques have been tried in an attempt to reduce allergen levels in homes. This study investigated the effect of dry heat on mite, cat, and dog allergens. METHODS: Samples (50 mg) of Dermatophagoides pteronyssinus and D. farinae cultures, and of house dust rich in the major cat and dog allergens Fel d 1 and Can f 1 were heated for 5, 10, 15, 30, and 60 min at 60 degrees, 80 degrees, 100 degrees, 120 degrees, and 140 degrees C. Control samples remained at room temperature. Extracts were assayed with the appropriate two-site mono- or mono/polyclonal sandwich ELISA. RESULTS: For Der p 1, the breakdown was proportional to temperature and heating time; after 30 min at 120 degrees C, allergen levels were reduced to < 1% of control. Der p 2 was more heat stable, requiring 140 degrees C for 30-60 min to achieve > 99% reduction. D. farinae groups 1 and 2 allergens showed results similar to those obtained with D. pteronyssinus. In contrast, Can f 1 and Fel d 1 were considerably more thermostable, with 50% and 70%, respectively, of allergen remaining after 60 min at 140 degrees C. CONCLUSIONS: The effect of dry heat on allergens increased with increasing time and temperature, cat and dog allergens demonstrating greater heat resistance than mite allergens. Dry heating methods may represent an alternative technique for removal of mite allergens; however, the greater stability of Fel d 1 and Can f 1 suggests that this procedure may not be appropriate for pet allergens.     

Interactions of surfactant protein D with pathogens, allergens and phagocytes

Surfactant protein D (SP-D) is considered to play an important role in innate immunity in the lungs by binding, via its multiple C-type lectin domains, to carbohydrate structures present on a range of viruses, bacteria, yeasts and fungi. The resulting agglutination of the target pathogens provides host defence which can be further enhanced by killing and clearance mechanisms mediated by phagocytic cells which carry receptors for SP-D. Recent findings suggest that SP-D, and the structurally related lung surfactant protein A (SP-A), may also modulate allergic reactions by binding certain glycosylated allergens. The finding of SP-D at a variety of other sites besides the lungs, such as the gastric mucosae, is suggestive that it may play a general protective role in several secretions.