Daily enteral feeding practice on the ICU: attainment of goals and interfering factors.

Background: The purpose of this study was to evaluate the daily feeding practice of enterally fed patients in an intensive care unit (ICU) and to study the impact of preset factors in reaching predefined optimal nutritional goals.

Methods: The feeding practice of all ICU patients receiving enteral nutrition for at least 48 hours was recorded during a 1-year period. Actual intake was expressed as the percentage of the prescribed volume of formula (a success is defined as 90% or more).

Occupancy of platelet receptors for platelet-activating factor in asthmatic patients during an allergen-induced bronchoconstrictive reaction.

The administration of platelet-activating factor (PAF) to human subjects triggers asthma-like responses. We investigated whether a bronchoconstrictive reaction was accompanied by the release of PAF in the circulation of allergic asthmatics. The appearance of PAF was assessed by measuring the number of freely accessible PAF-receptors on platelets in vitro, assuming that the contact between platelets and PAF in vivo would reduce the receptor binding of [3H]PAF in vitro.

Late asthmatic responses after exercise challenge are reproducible.

In this study the reproducibility of a late asthmatic reaction (LAR) after exercise challenge (EC) has been documented. Eighty-three hospitalized patients with asthma were challenged with exercise. The patients were examined according to a standardized protocol that comprised 8 minutes of bicycling at 90% of predicted heart rate.

The possible role of particular leukotrienes in the allergen-induced late-phase asthmatic reaction.

Challenge with allergen may provoke an early-phase and late-phase asthmatic reaction in allergic asthmatic individuals. Although the pathogenesis of the allergen-induced late-phase asthmatic reaction (LAR) is still poorly understood, the cell types and mediators involved in this reaction are considered to be of extreme importance for the understanding of the pathogenesis of asthma. Evidence has been provided that predominantly eosinophils penetrate into the bronchioli at the beginning of the LAR.

Leukotriene C4 formation by purified human eosinophils can be induced by arachidonic acid in the absence of calcium-ionophore A23187.

Addition of arachidonic acid (50 microM) to purified human eosinophils leads to the formation of considerable amounts of LTC4 [11.3 +/- 1.3) x 10(6) molecules/cell, mean +/- SEM, n = 10), 15-HETE [412 +/- 142) x 10(6) molecules/cell, mean +/- SEM, n = 3) and 15-series leukotrienes [35 +/- 15) x 10(6) molecules/cell, mean +/- SEM, n = 3).

Associated expression of CD1 antigen and Fc receptor for IgE on epidermal Langerhans cells from patients with atopic dermatitis.

The presence of Fc receptors for IgE on epidermal Langerhans cells (LC) from patients with atopic dermatitis (AD) was demonstrated by three different types of experiments. Firstly, cell-bound IgE on LC was removed by acid elution and restored by highly purified human myeloma IgE (IgE kappa). Secondly, after pepsin digestion of cell-bound IgE the number of LC staining with anti-human light chain (kappa, lambda) antibodies significantly decreased in contrast to the number of LC staining with anti-human epsilon heavy chain antibody.

Arachidonic acid can induce leukotriene C4 formation by purified human eosinophils in the absence of other stimuli.

Stimulation of purified human eosinophils with 50 microM arachidonic acid leads to the production of leukotriene C4, 15-hydroxy-eicosatetraenoic acid and 15-series leukotrienes. The ratio of the amounts of leukotriene C4 and 15-lipoxygenase products was found to be strongly dependent on the arachidonic acid concentration, being relatively large at low arachidonic acid concentrations and very small at high arachidonic acid concentrations. In the presence of 1 microM platelet-activating factor a significant elevation of leukotriene C4 formation is observed, whereas the formation of 15-lipoxygenase products remains unaltered.

Active participation of eosinophils in patch test reactions to inhalant allergens in patients with atopic dermatitis.

Intracutaneous testing and patch tests with house dust mite and grass pollen allergens were performed in patients with atopic dermatitis. Only patients with an immediate type skin reaction to house dust mite or grass pollen allergens showed a positive patch test reaction to these allergens 24-48 h after testing. Occasionally positive patch test reactions at 20 min, 2 h and 6 h were also observed.

The excretion of leukotriene E4 into urine following inhalation of leukotriene D4 by human individuals.

Healthy volunteers underwent bronchial challenge with increasing doses of nebulized leukotriene D4 (0.007 - 200 nmol) at 15 min intervals. Total amounts of 200 nmol (females) and 400 nmol (males) were inhaled, corresponding to approximately 100 nmol and 200 nmol deposited in the lung, respectively.

Birch pollen asthma in The Netherlands.

The occurrence of birch pollen asthma is related to high birch pollen concentrations in the air, and therefore this type of asthma is rather common in Scandinavia. High birch pollen concentrations are rare in The Netherlands, but in the spring of 1984 extremely high levels were reached, whereas the concentrations of alder and hazel pollen were very low. During this period nine pollinosis patients known to the allergist developed asthmatic complaints.

Platelet-activating factor (PAF-acether) induced leukotriene C4 formation and luminol dependent chemiluminescence by human eosinophils.

Human eosinophils are capable of synthesizing almost exclusively the strongly spasmogenic compound LTC4 when stimulated with either the calcium ionophore A 23187 or opsonized zymosan (OZ). Although PAF-acether in concentrations ranging from 10 nM to 1 microM is hardly capable of inducing significant LTC4 synthesis itself, it significantly enhances the OZ-induced LTC4 formation at a concentration of 1 microM. However, at a concentration of 10 microM, PAF-acether itself is capable of inducing LTC4 formation comparable with that induced by OZ.

The presence of IgE molecules on epidermal Langerhans cells in patients with atopic dermatitis.

Skin sections of clinically involved and clinically normal-looking skin from patients with atopic dermatitis were incubated with anti-human IgE antibodies using the indirect immunoperoxidase technique. Apart from positive dermal anti-IgE staining, positive epidermal anti-IgE staining was also observed. The morphology of the epidermal staining cells suggested the involvement of dendritic cells.

Leukotrienes and their possible significance for the pathogenesis of asthma.

Six years ago the structure of slow reacting substance of anaphylaxis (SRS-A), a strongly bronchoconstrictive substance, has been unravelled SRS-A proved to be a mixture of different closely related compounds, now denominated as sulfidopeptide Leukotrienes. Leukotrienes possess a conjugated triene system and one or more oxygen functions. They are formed from membrane derived arachidonic acid by an initial oxygenation by the enzyme lipoxygenase.

On the optimal conditions of LTC4 formation by human eosinophils in vitro.

The optimal conditions for the -in vitro- LTC4 formation by the human eosinophil, isolated from peripheral blood, have been investigated in detail. LTC4 formation was found strongly Ca2+ and ionophore dependent and was complete after 20 min. Maximal LTC4 production was observed in the presence of 2 mM Ca2+, 10 microM ionophore A23187 and 5 mM glutathione.

Exclusive leukotriene C4 synthesis by purified human eosinophils induced by opsonized zymosan.

Purified human eosinophils were challenged with N-formyl-methionyl-leucyl-phenylalanine, leukotriene B4, platelet-activating-factor, valyl-glycyl-seryl-glutamic acid, phorbol myristate acetate, zymosan, opsonized zymosan and the calcium ionophore A23187 to induce leukotriene synthesis. Reversed-phase high performance liquid chromatography analysis demonstrated the almost exclusive synthesis of leukotriene C4 by eosinophils of 11 healthy donors after challenge with opsonized zymosan [(22 +/- 4) X 10(6) molecules LTC4/cell, mean +/- SE] or the calcium ionophore A23187 [(54 +/- 7) X 10(6) molecules LTC4/cell, mean +/- SE]. The other agents were not capable of inducing leukotriene formation.

Some fundamental points concerning the clinical aspects of desensitization.

Continued exposure of target cells to a hormonal agonist frequently leads to a blunted response to that agonist. This process has been termed desensitization, refractoriness, tolerance or tachyphylaxis. The receptor involved in case of beta-sympathomimetics is the beta-adrenergic receptor.

Measurement of total IgE antibody levels in lacrimal fluid of patients suffering from atopic and non-atopic eye disorders. Evidence for local IgE production in atopic eye disorders?

Total IgE levels in lacrimal fluid of patients suffering from different eye disorders were quantitatively measured by a modification of the paper radio immuno sorbent test (PRIST). The geometric mean values for patients with atopic conjunctivitis, patients with keratoconjunctivitis vernalis, and patients with asthma without conjunctivitis differed significantly from those for control persons and those for patients without atopic conjunctivitis. Besides lacrimal fluid IgE levels, serum IgE levels as well as lacrimal fluid and serum albumin levels were measured.

Specific leukotriene formation by purified human eosinophils and neutrophils.

Human granulocytes isolated from peripheral blood have been described to synthesize both LTB4 and LTC4 from arachidonic acid. We have observed that the amount of LTC4 produced by human granulocyte preparations is strongly dependent on the relative amount of eosinophils. To investigate a possibly significant difference in leukotriene synthesis of the eosinophilic and neutrophilic granulocytes, we developed a purification method to isolate both cell types from granulocytes obtained from the blood of healthy donors.

Changes in the beta-adrenergic system due to beta-adrenergic therapy: clinical consequences.

Continued exposure to a hormonal agonist often leads to a blunted response to that agonist. This process has been termed desensitization, refractoriness, tolerance or tachyphylaxis. Continued exposure to beta-adrenergic therapy has been shown to reduce the beta-adrenergic response of white blood cells as well as the number of beta-adrenergic binding places on those cells.