B. Diamant

Flour Allergy in Bakers

Extract of wheat flour obtained by extraction, centrifugation and dialysis was immunochemically characterized by quantitative immunoelectrophoresis using rabbit antibodies. The analysis revealed wheat flour to be composed of 40 antigens, some of which were immunologically partially identical with antigens of rye flour and of common grass pollen. Furthermore, antigens of the gliadin fraction of wheat flour were identified. 25 bakers with allergic complaints working in and around Copenhagen were clinically tested with wheat flour and related extracts. Among 13 bakers with respiratory complaints (asthma and/or rhinitis), 11 showed positive reactions to wheat flour extract when tested in histamine release from basophil leukocytes radioallergosorbent test and skin test, whereas further 2 were positive in the basophil test only. The ability of the IgE of individual sera to adsorb to the individual antigens of wheat flour was examined by means of crossed radioimmunoelectrophoresis. On the basis of these results, individual allergenic components of wheat flour were identified, three of these with comparatively high affinity and frequency.

Effect of Divalent Cations and Metabolic Energy on the Anaphylactic Histamine Release from Rat Peritoneal Mast Cells

Histamine release induced by the antigen from mast cells obtained from actively sensitized rats was enhanced by the same concentration of calcium in the medium, irrespective of whether the mast cells

Coenzyme Q10, Alpha-Tocopherol and Free Cholesterol in HDL and LDL Fractions

Twenty-three randomly selected plasma samples from apparently healthy, middle aged men were analysed for coenzyme Q10 (CoQ10), alpha-tocopherol (AT) and free cholesterol (FC) in: 1) whole plasma, 2) the HDL lipoprotein fraction after LDL precipitation (VLDL + LDL). CoQ10, AT and FC in plasma averaged 0.69 +/- .11, 6.74 +/- 1.78 micrograms x ml-1 and 0.59 +/- .11 mg x ml-1 and in HDL 0.17, 3.24 micrograms x ml-1 and 0.17 mg x ml-1 or 29, 48 and 29% of plasma values. Amounts of CoQ10 and AT were correlated to that of FC in all pools. The amount of HDL-CoQ10 but not of HDL-AT fell, with the HDL-FC expressed as the fraction of plasma FC. In all pools, N-AT versus AT initially increased and then levelled off, indicating saturation like conditions in contrast to CoQ10. Thus, CoQ10 and AT are differently allocated in HDL and LDL. This might have a bearing both on the suggested lipoprotein protection against peroxidation by these two antioxidants, but also on the distribution and allocation in different organs of CoQ10 and AT by HDL and LDL transportation.

Increased Permeability of the Rat Mast Cell Membrane to Sodium and Potassium Caused by Extracellular ATP and its Relationship to Histamine Release

Extracellular ATP induced a prompt increase in sodium and decrease in potassium contents of isolated rat mast cells. The effects on the cation composition of the cells preceded the histamine release i

Ubiquinone and α-tocopherol in plasma; means of translocation or depot

SummaryUbiquinone (UQ) and α-tocopherol (AT) are two highly lipophilic antioxidants which can be dissolved only in lipid layers or attached to protein structures. Analyses of both UQ and AT in whole blood and plasma demonstrate identical values, which excludes any significant allocation to blood cells. The lipoidic plasma structures constitute the plasma lipoprotein fractions of high (HDL), low (LDL), and very low (VLDL) density in addition to chylomicrons. This means by definition that blood and plasma UQ and AT values are limited if not related to the lipoidic deposit volume. UQ and AT increase linearly with free cholesterol (FC). FC has therefore been suggested to be a good marker for the deposit volume. The ratios UQ and AT over FC - normalized UQ (N-UQ) and normalized AT (N-AT) - have been computed for inter-and intraindividual comparisons. With a plasma UQ content of 1 μg/ml (≈ 1 μmol/l) and a plasma volume of 41, UQ makes up about 15% of the total heart content or under 1% of UQ in skeletal muscle. The corresponding value for the total extracellular UQ content is less than 2%. This means that extracellular UQ has no or a very minor role as a UQ depot. The same is true for AT. However, for transportation and allocation determinations of N-UQ and N-AT are relevant. Assuming only a lipoprotein-related transportation, healthy persons have saturated plasma UQ and AT values in only 25% and 10% of the population, respectively. All patient categories studied have been found nonsaturated. VLDL plus LDL constitute some 90% of the UQ deposit volume. VLDL and LDL are released from the liver to transport fat, for example, to muscle tissue. HDL has a corresponding cholesterol-transporting function. Uptake depends on the local lipoprotein lipase activity. Do these transports also function as means for UQ and AT transport? Per unit of FC, UQ content in VLDL+LDL is about five times that in HDL. The corresponding AT value is about unity. This difference between UQ and AT storage does not exclude the possibility that VLDL+LDL particles possess the ability to transport UQ between different compartments when so necessary.

Binding of45Calcium to isolated rat mast cells in connection with histamine release

The time courses for histamine release and uptake of45Ca were compared on isolated rat mast cells after stimulation under different experimental conditions with antigen, compound 48/80, ATP, or the ionophore A23187. Except for ATP the results did not show a time-dependent correlation between histamine release and45Ca uptake.The uptake of45Ca under conditions where membrane-bound calcium is utilized for optimal anaphylactic histamine release did not differ from that of controls, whereas the presence of45Ca in the incubation medium led to a substantial uptake without influence on the histamine release.The uptake of45Ca induced by antigen or compound 48/80 was completely inhibited by antimycin A as confirmed by the use of two different methods. In addition, an energy-dependent restitution of the permeability properties of the plasma membrane seemed to follow histamine release. Antimycin A partly reduced the uptake of45Ca after stimulation with ATP, and did not affect binding following exposure of the cells to the ionophores A23187 or X537A.The ionophore A23187 was able to reduce the45Ca content of mast cells previously loaded with the isotope. Mast cells pretreated with A23187 in the absence of extracellular calcium did, after washing, accumulate substantial amounts of45Ca without release of histamine.The results suggest that only small amounts of calcium are required to trigger histamine release and that studies with45Ca do not distinguish between specific uptake of calcium and nonspecific equilibration secondary to morphological secretory changes.

ATP Level and CO2 Production of Mast Cells in Anaphylaxis

The short and long-term effects of the anaphylactic reaction on energy metabolism of rat mast cells were studied. The ATP content amounted to 12.1 ± 1.1 ×10––16 moles per mast cell in different experiments. Following antigen challenge (horse serum 0.6%), a significant decrease of the ATP level was obtained: 16% at 30 sec and 38% at 2 min with no further change up to 10 min. The decrease was evident in the absence of metabolic substrates as well as in the presence of pyruvate. However, glucose completely counteracted the fall in ATP level. The fall in ATP content and the release of histamine were both related to the antigen concentration. No change in ATP level was observed in controls or by antigen challenge of mast cells from nonsensitized rats. Pyruvate was metabolized by oxidative metabolism in the mast cell. The CO2 production amounted to 2.2 ×10––16 moles CO2/mast cell/min and was completely abolished by antimycin A. Antigen challenge of sensitized rat mast cells increased the CO2 production by 30%, while no increase was observed with cells from non-sensitized rats. The increase in oxidative metabolism was not correlated to the histamine release. Thus, the same enhancement in CO2 production was obtained with antigen concentrations over a great range. 2,4-Dinitrophenol mimicked the effects of antigen on the ATP level as well as on the oxidative metabolism of pyruvate. The results indicate that the antigen-antibody reaction exerts effects on the energy production in the mast cells consistent with an uncoupling of oxidative phospho-rylation.

Sodium fluoride--a stimulus for a calcium-triggered secretory process.

Calcium triggers the secretion of histamine from mast cells after previous exposure of the cells to sodium fluoride. The secretory process can be divided into a fluoride-activating step and a calcium-induced secretory step dependent on cellular metabolic energy. The secretory response induced by compound 48/80 in the absence of extracellular calcium was found to decrease after fluoride pretreatment of the cells. The response was, however, unaffected, provided calcium was introduced to the cells simultaneously with compound 48/80.

The influence of phosphatidyl serine on the release of histamine from isolated rat mast cells induced by different agents

The influence of phosphatidyl serine (PS) on histamine release from isolated rat mast cells induced by antigen, compound 48/80, adenosine-5′-triphosphate (ATP), the ionophore A23187, and decylamine was studied. PS enhanced antigen-induced release but inhibited the release caused by compound 48/80, A23187, and decylamine. PS did not influence the release induced by ATP. The different effects of PS on the action of the various histamine releasing agents do not conform to a unifying model for the action of PS on the release process. Possible interactions between PS and the agents in the incubation medium as well as at specific reactive sites on the plasma membrane might explain some of the effects of PS. Consequently, the results cannot be used as evidence for the existence of basic differences in the release process induced by various calcium-and energy-dependent releasing agents.

Morphological Changes Induced by ATP on Rat Mast Cells and their Relationship to Histamine Release

Discharge of granules from isolated rat mast cells could be observed concomitantly with the histamine release from the cells when incubated with adenosine 5′-triphosphate (ATP) in the presence of Ca