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Biomedical subjects

H Bisgaard

Publications and source records attributed to H Bisgaard.

At least 19 recordsLinked to original sources
PubMed1992

A specific assay for leukotriene B4 in human whole blood.

Leukotrienes (LTs) are potent mediators of inflammatory and allergic responses, and are present in biological fluids in minute amounts, that is, in the picogram range. The aim of this study was to develop and validate a method for determination of LTB4 synthesized in vitro in human whole blood. Heparinized blood was stimulated with calcium-ionophore A23187 at 37 degrees C. After 30 min cells were separated by centrifugation. LTB4 was analyzed by radioimmunoassay (RIA). When sample preparation was restricted to protein precipitation with acetone, interference was demonstrated by lack of parallelism between standard and sample dilution curves. Purification was, therefore, extended by combinations of the following steps: 1) protein precipitation, 2) lipid extractions, and 3) high-performance liquid chromatography (HPLC). One of two commercially available LTB4 standards was found to contain multiple components, several of which were immunoreactive in RIA. Even for the standard containing pure LTB4, interference was demonstrated by lack of parallelism between sample and standard dilution curves. Testing eight combinations of varying purification steps, we found that only a three-step purification procedure, including 1) solid-phase extraction, 2) protein precipitation at -20 degrees C, and 3) HPLC, was able to eliminate interference in RIA. Using this procedure, the recovery was 78%. Stimulation of whole blood from normal subjects with calcium-ionophore showed optimal LTB4 production at 10 microM ionophore, yielding 6.6 ng LTB4/mL blood.

Chromatography, High Pressure Liquid↗
PubMed1991

Bacteria-induced histamine release from human bronchoalveolar cells and blood leukocytes.

Histamine release induced by Staphylococcus aureus was examined in cells obtained by bronchoalveolar lavage (BAL) in non-atopic individuals. Approximately half of the individuals responded with mediator release to the bacterium, and the release was found to be time- and concentration dependent. No difference was found between the patients who responded and those who did not respond in regard to age, sex, smoker/non-smoker, % recovery of BAL-fluid, total cell count, differential cell counts, histamine content per mast cell, or diagnoses. Also stimulation of the BAL-cells with the calcium-ionophore A23187 resulted in histamine release. S. aureus-induced histamine release from basophils was examined in leukocyte suspensions obtained from the same individuals, and in all experiments release was found. The dose-response curves were similar to those obtained with BAL cells. The bacteria-induced mediator release from superficially lying cells in the airways epithelium might be of importance for the precipitation or exacerbation of bronchial asthma in respiratory tract infections.

Adult↗
PubMed1991

Adrenal function in asthmatic children treated with inhaled budesonide.

The effect of the inhaled topical steroid budesonide on adrenal function was evaluated in 33 children (aged 7-15 years) with moderate bronchial asthma. The trial was designed as a prospective single-blind study of the effect of budesonide in daily doses of 200 microgram through 400 microgram to 800 micrograms in three randomized consecutive periods of 8 weeks. The unstimulated diurnal production of cortisol was assessed by measurement of free cortisol in 24-hour urine samples at the end of each period. No significant dose-related suppression was found. The cortisol production did not differ significantly during treatment with 800 microgram budesonide as compared to treatment with 200 microgram budesonide (95% confidence interval: 74%-112%). It is concluded, that budesonide is a topical steroid with a favourable ratio between topical and systemic effects in asthmatic children.

Administration, Inhalation↗
PubMed1990

Inhaled budesonide for treatment of recurrent wheezing in early childhood.

77 children, aged 11 to 36 months (mean 24) with moderately severe recurrent wheezing, were treated with budesonide pressurised aerosol 400 micrograms twice daily or placebo for 12 weeks in a double-blind, parallel-group trial. Aerosols were inhaled from a spacer with a facemask. Budesonide significantly improved symptom scores of wheezing, sleep disturbance, and patient happiness. The frequency of severe exacerbations that required a course of oral prednisolone was also significantly reduced. The treatment effect appeared to be fully established after 6-8 weeks and no side-effects could be ascribed to the active treatment. The findings indicate that young children below 3 years of age can inhale a pressurised aerosol from a spacer with a facemask. Use of topically active glucocorticosteroids with this simple device may reduce symptoms and distress in young children with moderately severe recurrent wheeze and dyspnoea, and possibly reduce their requirement for oral steroids.

Administration, Inhalation↗
PubMed1990

Allergen-induced increase of eosinophil cationic protein in nasal lavage fluid: effect of the glucocorticoid budesonide.

It was our aim to study the effect of nasal allergen provocation on the concentration of eosinophil cationic protein (ECP) in nasal lavage fluid, with and without glucocorticoid pretreatment. Twenty grass-pollen sensitive volunteers were provoked outside the pollen season on 2 consecutive days after pretreatment for 2 weeks with the glucocorticoid, budesonide, as a nasal spray (400 micrograms/day) and with placebo with a double-blind, crossover design. Nasal lavage fluid was repeatedly collected during a 10-hour period to study both early and late-phase responses. 99mTechnetium-albumin was added to the lavage fluid, making it possible to calculate the amount of secretion and the degree of dilution. The results were as follows: (1) There was no correlation between ECP concentration and dilution factor in the individual samples. (2) The mean concentration of ECP in lavage fluid from untreated, prechallenge noses was 400 micrograms/L. (3) The ECP level did not increase during the early phase response. (4) There was a late occurring increase in the ECP concentration (6 to 24 hours). (5) This increase was completely inhibited by budesonide pretreatment. (6) The glucocorticoid therapy also reduced the prechallenge ECP concentration. In conclusion, allergen provocation in the nose results in a late occurring increase of ECP in nasal lavage fluid, and one of the therapeutic effects of topical glucocorticoid therapy may be an inhibition of the allergen-induced increase of this cytotoxic molecule.

Adult↗
PubMed1989

Staphylococcus aureus and influenza A virus stimulate human bronchoalveolar cells to release histamine and leukotrienes.

Mediator release was examined from superficially lying cells in the airway epithelium obtained by bronchoalveolar lavage (BAL) in 13 non-atopic individuals. The BAL-cells were incubated (20 min, 37 degrees C) with Staphylococcus (Staph.) aureus or with human influenza A virus Staph. aureus was found to release histamine from cells from 7 of the 13 individuals and influenza A virus in 3 of 5 persons. Furthermore, Staph, aureus stimulated the BAL-cells to release leukotriene B4 in 7 of 11 subjects, whereas no release was found by influenza A virus in 7 examined persons. When cells from 4 persons were stimulated with Staph. aureus no release of leukotriene C4 was found. The mediator release caused by bacteria and virus might be of importance for the exacerbation of bronchial asthma in upper respiratory tract infections, since histamine is assumed to increase the epithelial permeability with entrance of allergens and other insulting particles, and leukotriene B4 facilitates airway inflammation.

Adult↗
PubMed1989

Prostaglandin E1 and prostaglandin F2 alpha in exudate in nickel allergy.

Ten nickel-allergic patients and 5 healthy control subjects participated in a study of the kinetics of the flux and concentration of migrated leukocytes and extracellular PGE1 and PGF2 alpha during a 48 h period, using a skin chamber technique. The patients were provided with two skin chambers, one with and one without nickel challenge. A higher flux of leukocytes, PGE1 and PGF2 alpha was observed during the second day of allergen exposure, while the concentrations probably due to dilution were unchanged or diminished, indicating an unspecific role of the prostaglandins during the contact allergic reaction. No correlations were found within the groups between the migration of leukocytes and the prostaglandin content.

Adult↗
PubMed1988

Adrenal function in children with bronchial asthma treated with beclomethasone dipropionate or budesonide.

The effect of inhaled beclomethasone dipropionate and budesonide on the adrenal function was studied in 30 children (aged 7 to 15 years) with mild bronchial asthma. The trial was designed as a prospective double-blind parallel study of the effect of stepwise increase of either beclomethasone dipropionate or budesonide from 200 micrograms through 400 micrograms, to 800 micrograms daily in three consecutive periods of 4 weeks. At the end of each period, the adrenal stress response was evaluated by measurements of serum cortisol and androstenedione during a short adrenocorticotropic hormone test. The unstimulated diurnal production of glucocorticosteroids was assessed by measurements of free cortisol in 24-hour urine samples. Free cortisol in urine was found a valid measure of the total diurnal excretion of cortisol metabolites, since it exhibited a good correlation to the fractional cortisol metabolites measured by gas chromatography. The adrenal response to adrenocorticotropic hormone stimulation was unaffected by treatment or dose. The unstimulated diurnal production of glucocorticosteroids demonstrated a highly significant dose-related suppression in response to the inhaled steroids. No significant difference was found between the two topical steroids (probability value 5.3%), and yet the suppression was apparent in the group of children treated with beclomethasone dipropionate but not in the group of children treated with budesonide. Further studies are desirable in order to ascertain whether budesonide offers an improved ratio between beneficial anti-inflammatory effect and unwanted systemic activity.

Adolescent↗
PubMed1988

Lactoferrin, myeloperoxidase, lysozyme and eosinophil cationic protein in exudate in delayed type hypersensitivity.

A skin window technique was used to study the morphology of leucocytes in upper dermis and exudate during nickel challenge in patients with contact allergy to nickel. Contact allergic patients and healthy volunteers tested with a skin widow without addition of nickel to the chamber medium served as controls. The morphology of the leucocytes in dermis was studied in biopsies taken 8, 24, or 48 h after skin window application, and in a parallel test the morphology of the exudate was examined by sequential collection of the chamber medium during a 48 h period. The infiltrate in dermis of contact allergic patients with nickel challenge in the chamber medium showed a time-dependent increase of mononuclear cells, eosinophils and basophils and a concomitant decrease of polymorphonuclear granulocytes, characteristic of a combined specific and unspecific inflammation. The morphology of the exudate in contact allergic patients exposed to nickel showed a dominance of polymorphonuclear granulocytes throughout the study period, while mononuclear cells, eosinophils and basophils were detected at a much lower quantity and with a considerable delay. Further, we studied the kinetics of the leucocyte granule proteins: lactoferrin, myeloperoxidase, lysozyme and eosinophil cationic protein in exudate fluid in a parallel test. A significant higher flux was found for all during the second day of allergen exposure compared to contact allergic patients without allergen challenge as well as normal volunteers. The increased protein fluxes were not accompanied by an increased flux of polymorphonuclear granulocytes in the exudate.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1988

Leukotriene C4 and histamine in early allergic reaction in the nose.

We have examined the measurements of LTC4 and histamine in nasal lavage fluids and blown secretions as a possible model of the early mediator events during nasal allergy. A nasal challenge with grass pollen extract was undertaken on two separate occasions in 20 patients with a history of seasonal rhinitis and a positive immediate skin test to grass pollen. A 2 ml nasal lavage was performed before allergen challenge, and blown secretion collected separately 15 min after the provocation, followed by a final 2 ml nasal lavage. The dilution of nasal secretion by the lavage fluid was determined using 99mTc-labelled albumin as an exogenous marker added to the fluid. The amounts of admixture in the nasal lavages did not correlate to the concentrations of LTC4 and histamine, indicating that the variable amounts of nasal secretion in nasal lavage do not constitute a confounding variable for measurements of LTC4 and histamine. In the pre-challenge lavages, the median concentrations, of LTC4 and histamine were 1.7 and 52 nmol/l respectively. Following allergen challenge neither LTC4 nor histamine measured in nasal lavage showed any significant change from pre-challenge baseline values. However, measurements of both mediators in the blown secretion showed a significantly higher concentration than in the pre- or post-challenge lavage samples, compatible with transitory release during the acute allergic reaction. However, it seems doubtful whether measurements of LTC4 or histamine can be compared between blown secretion and nasal lavage fluid, even if the dilution factor is disregarded.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Bronchial effects of leukotriene D4 inhalation in normal human lung.

The aim of the study was to investigate whether inhaled leukotriene (LT) D4 could mimic the characteristics of asthmatic patients after allergen-induced attack, i.e. a prolonged subclinical bronchial obstruction, an increased reactivity of the airways and a late reaction. The effects of LTD4 were compared with those of histamine and the mechanism of action sought. Thirty-three non-atopic individuals participated in the study. The two drugs were inhaled as an aerosol of small particles causing a relative peripheral deposition pattern in order to mimic the preferential involvement of peripheral airways in asthmatic patients out of attack. LTD4 caused a dose-dependent obstruction of the airways as measured by partial flow-volume curves and volume of trapped gas, yet only minor changes in forced expiratory volume in 1 s (FEV1) and peak expiratory flow rate. LTD4 was 1900-7000 times more potent than histamine. LTD4 inhalations were almost symptomless as opposed to the irritative and dyspnoeic symptoms seen after inhalation of histamine. The time duration for the induced change in partial flow-volume curves was the same for the two drugs. Approximately 30 min elapsed until the bronchial obstruction had decreased by 50% of the maximum effect, and no delayed reaction was observed within 10 h. The reactivity of the airways did not change during 10 h after inhalation of LTD4 as tested by repeated exercise challenges. Pretreatment with ipratropium bromide prevented the effect of LTD4 on FEV1, yet not on partial flow-volume curves. Pretreatment with either cimetidine and mepyramine or with indomethacin, did not affect the bronchial obstruction after LTD4.(ABSTRACT TRUNCATED AT 250 WORDS)

Airway Resistance↗
PubMed1987

Measurement of secretion in nasal lavage.

1. The amount of admixture in nasal lavage fluids was determined by addition of 99mTc labelled albumin, providing a correction factor for measurements of cellular material and humoral substances in nasal lavage return as well as a quantitative measure of nasal secretions. 2. Albumin was chosen as marker molecule, since only negligible amounts were absorbed or adsorbed to the mucosa during the nasal lavage. 3. Labelling of the albumin with 99mTc ensured an accuracy of measurements only limited by the precision of the weighing. The isotope allowed for the determination of the amount of admixed secretion to be carried out on the whole sample of lavage fluid, thereby avoiding the necessity of complete admixture between marker and lavage fluid which would be pertinent to marker molecules measured chemically. The radiation from a nasal lavage is minimal and the procedure is fully acceptable for repeated use in humans. 4. The nasal lavage technique adopted allowed the return of 99.2% (median value) of the instilled volume. The area irrigated was visualized on a gamma-camera, and was demonstrated to cover an area larger than the area reached by challenge from a pumpspray, i.e. a large part of the nose, yet not the oropharynx. 5. A dose related increase in nasal secretion harvested by the nasal lavage in 10 persons challenged with histamine chloride could be demonstrated by this technique. 6. It is concluded that the use of 99mTc-albumin in a nasal washing provides a safe, simple and quick method for determination of the admixed nasal secretion with a remarkable degree of accuracy.(ABSTRACT TRUNCATED AT 250 WORDS)

Absorption↗
PubMed1987

Vascular effects of leukotriene D4 in human skin.

Leukotriene D4 (LTD4) increased the blood flow rate in human skin, equipotent to histamine in the dose range of 3.1-200 pmol. The vasodilatation lasted for up to 60 min, and no late reactions occurred. Indomethacin did not affect the LTD4-induced blood flow rate. H1 and H2 antagonists reduced the increase in blood flow rate, but did not abolish the response to LTD4. Local nerve block inhibited the axon reflex-mediated flare component of the LTD4-induced blood flow rate, leaving a local red reaction. This local red reaction was not affected by H1 and H2 antagonists. These results indicate histamine as a mediator of the axon reflex, and show that LTD4 causes a direct vasodilatory effect that is not mediated via histamine or cyclooxygenase products. The laser-Doppler flowmeter was applied for dynamic studies of the vasopressor response in the skin during a Valsalva maneuver, and the relative changes in blood flow were confirmed by control estimates of the blood flow rate by a 133xenon washout method. The pressor response to a Valsalva maneuver was reversed by local nerve block, but not affected by LTD4. Therefore LTD4 did not interfere with the sympathetic activity on the cutaneous vessels. Leukotriene D4 caused a dose-dependent wheal reaction, equipotent to histamine in the dose range of 0.2-200 pmol. Only minor whealing occurred when the vasculature to the test arm was occluded before injection of LTD4 and the circulation restored 30 min later. Most of the LTD4 was apparently metabolized within this period. Subsequent injections of LTD4 into the same sites demonstrated the development of tachyphylaxis with respect to whealing. This evidence suggests that LTD4 cannot mediate sustained inflammation. The injections of LTD4 caused neither pain nor itching. In conclusion, the elucidated properties point to LTD4 as a possible mediator of microvascular changes during acute inflammation.

Adolescent↗
PubMed1987

SRS-A leukotrienes decrease the activity of human respiratory cilia.

We have studied the effects of the slow reacting substance of anaphylaxis (SRS-A) constituents leukotrienes (LT) C4 and D4 on the ciliary activity of human respiratory cells. The ciliary beat frequency on human nasal cells harvested by cell scraping from the inferior turbinate was measured in a blind design by a microphoto-oscillographic technique. A total of 740 ciliated cells from seventy-four cell scrapings were studied. Mean baseline of ciliary beat frequency was 10.2 Hz. The ciliary beat frequency exhibited a pronounced variability in the spontaneous changes between the cell scrapings, yet less so within cell samples from the cell scrapings. We, therefore, evaluated the effect of the test solutions relative to the spontaneous decrease found during simultaneous perfusion with control solution of samples from the same cell scrapings. LTC4, 3-300 nmol/l, caused a highly significantly dose-related decrease in the ciliary beat frequency by up to approximately 20% as compared to the corresponding control solution. The effect of LTC4 was significantly inhibited by the SRS-A receptor antagonist FPL 55712 (10 mumol/l), but not by indomethacin (10 mumol/l). LTD4, 300 nmol/l, also decreased the ciliary beat frequency. LTB4, which is a leukotriene, although without the sulphidopeptide side chain of the SRS-A leukotrienes, did not affect the ciliary beat frequency in a concentration of 100 nmol/l. This would seem to confirm the structure specificity of the elucidated effect of the SRS-A leukotrienes. Histamine (100 mumol/l) did not affect the ciliary beat frequency.(ABSTRACT TRUNCATED AT 250 WORDS)

Chromones↗