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Biomedical subjects

M Stöber

Publications and source records attributed to M Stöber.

At least 19 recordsLinked to original sources
PubMed2004

Comparison of in vitro-activity of commonly used topical glucocorticoids on cytokine- and phospholipase inhibition.

BACKGROUND AND OBJECTIVES: Topical glucocorticoids (GCs) are potent inhibitors of cellular inflammatory mediator production. Differences in receptor binding activities are believed to correlate with inhibition of mediator release and anti-inflammatory efficacy in vivo. To further assess this hypothesis we compared in cultured human monocytes the inhibitory activity of classic synthetic GCs on leukotriene B4 (LTB4), prostaglandin E2 (PGE2), interleukin 1 beta (IL-1beta) and c-phospholipase A 2 activity (cPLA2). METHODS: Normal human monocytes (10(5) /ml) were tested for 20 hrs with increasing concentrations (range 10(-12) -10(-5) M) of triamcinolone acetonide (TAA) compared to beclomethasone dipropionate (BDP), budesonide (BUD), dexamethasone (DEX), or the ethanol diluent together with 10 microg/ml of lipopolysaccharide (LPS). Mediator production and spontaneous cPLA subset 2-activity was determined by direct enzyme immunoassay methods. RESULTS: TAA at therapeutically relevant concentration (10(-8) M) inhibited significantly (p<0.01, n = 9) mediator production of TNF-alpha > IL-1beta > TxB2 > LTB subset 4 in a dose dependent manner by 75%, 65%, 41%, and 33%. IL-1beta inhibition at 10(-8) M by TAA (65%)> BDP (52%)> BUD (47%) was not different (ANOVA, p>0.2). Also spontaneous cPLA2-activity at 10(-8) M was inhibited to a similar degree (ANOVA, p> 0.6) by BUD (17.3%) > TAA (11.4%) > BDP (8.6%). In the same culture conditions spontaneous PGE2-secretion was inhibited by BDP (28.8%) > BUD (24.2%) > TAA (11.4%) with no significant effect for TAA. CONCLUSION: Clinically well established GCs have a similar inhibitory capacity on monocyte cytokine production and surprisingly only weak effects on AA-metabolism. Small receptor binding activity may account for the lack of cytokine inhibition by subtherapeutic (<10(-8) M) airway concentrations of TAA and BDP. Partial mediator inhibition by GCs at therapeutically known airway concentrations may be relevant to control bursts of airway inflammation during acute exacerbation but unfavourable to effectively delay progression of chronic airway inflammation.

Administration, Cutaneous↗
PubMed2004

Different mechanisms of action of beta2-adrenergic receptor agonists: a comparison of reproterol, fenoterol and salbutamol on monocyte cyclic-AMP and leukotriene B4 production in vitro.

BACKGROUND: Beta2-adrenergic receptor agonists have several effects on airway function, most of which are mediated in a variety of cell types resulting in increased c-AMP-production and inhibition of inflammatory mediator production. However, their stimulating effects on cAMP-production became known to be inversed by increasing phosphodiesterase (PDE) activity and degradation of cAMP. Therefore, in this study we have evaluated the efficacy of reproterol, a dual acting beta2-adrenoceptor agonist and PDE-inhibitor, as compared to salbutamol and fenoterol with respect to production of cAMP and LTB4 in cultured monocytes. METHODS: Isolated human monocytes (10(5)/ml) were incubated (n = 9) in suspension with beta2-adrenoceptor agonists (10(-10) -10(-4) M) for 30 minutes with and without IBMX. Then, cAMP production was determined following treatment with Triton-X100. Production of LTB4 was measured following incubation of beta2-adrenoceptor agonists for 4 hrs in the presence of LPS (10 mg/ml). cAMP and LTB subset 4 were measured in culture supernatants by enzyme immunoassay. RESULTS: At 10(-5) M, production of cAMP was significantly stimulated by reproterol > fenoterol > salbutamol in a dose-dependent manner to an extent of *128%, *65%, 13% (*p<0.04) respectively. In contrast, LTB4-production was inhibited significantly to a similar degree by salbutamol and reproterol in a dose-dependent manner by 59% and 49% (10(-5) M, p<0.03), respectively, with decreasing inhibition (15%) after fenoterol. Following co-incubation with IBMX, cAMP production only increased significantly (p<0.002) after fenoterol (+110%) compared to salbutamol (+29%) and reproterol (+50%) (ANOVA, p<0.001). CONCLUSION: These data suggest effects of the theophylline constituent of reproterol to inhibit adenylyl cyclase induced phosphodiesterase activity. The advantageous synergistic effects of reproterol on cAMP-production need to be further explored in trials.

1-Methyl-3-isobutylxanthine↗
PubMed2004

Post surgical development of inflammatory adhesions and reticular function in cows suffering from traumatic reticuloperitonitis.

Inflammatory adhesions between reticulum and ventral abdomen in patients suffering traumatic reticuloperitonitis (TRP) may induce a massive inhibition of reticular contractions and thereby an impairment of the separation process of particles in the reticulorumen. However, a substantial disturbance of digesta passage (Hoflund-syndrome) is found only in a few TRP-cows. We hypothesized that this is due to a retrieval of reticular motility due to rebuilding and degradation of adhesions within months after the removal of the foreign body as the primary inflammatory stimulus. Accordingly, it was the objective of this study (a) to assess the extent and structure of inflammatory adhesions in cows with TRP over a period of six months following surgery and (b) to persecute reticular function by characterizing the sequence of reticular contractions sonographically and by assessment of particle size distribution in the faeces of patients by means of wet-sieving. Twenty-six cows suffering from TRP were studied on the day of rumenotomy (day 1) and on day 6, day 12 and 6 months post operationem. Additionally, six healthy control cows were investigated once. All cows were on a hay and concentrate diet. On day 1, the reticular floor and the reticular wall were affected by adhesions in varying extent in all cows; the contraction distance and contraction velocity of the reticulum were markedly reduced and the portion of large particles in the faces increased compared to healthy cows. On day 12, the portion of large particles did not vary any more from that of control cows; a tendency towards an increased contraction distance compared to day 1 was found. Sonographically, only marginal differences were detected in respect to extent and consistency of adhesions. Six months after rumenotomy, in 9 of 16 re-investigated cows sonography revealed no adhesions at the reticulum at all, in other cases the extent of adhesions shrunk considerably. Contraction distance and contraction velocity and particle size distribution in the faeces were found to be nearly comparable to that of control cows. It is concluded that inflammatory adhesions disappear in the majority of the TRP-patients, as a consequence reticular function normalizes. A serious disturbance of digesta passage seems to develop exclusively in those patients with the most extensive adhesions and may be also in such cows, where the primary adhesions cause the development of extensive abscesses.

Animals↗
PubMed2003

[Animal nutrition for veterinarians--actual cases: tulip bulbs with leaves (Tulipa gesneriana)--an unusual and high risk plant for ruminant feeding].

14 cattle (mainly younger ones) of a total of 50 extensively kept Galloways died within 6 weeks in late winter 2001/02. According to the owner's report, grass growth had been rather poor; therefore, the herd was fed additionally hay as well as large amounts of tulip onions. In the microbiological examination a highly reduced hygienic quality of the roughage could be detected. In the rumen contents of two dissected young cattle parts of tulip onions were found. According to pertinent literature, tulip onions (in particular their external layers) contain variant-specific amounts of anti-nutritive substances; main active agents are tulipin (a glycoprotein), tuliposid A and B, and lectins. They may cause intensive mucosal irritation, accompanied by reduced feed digestion and body-weight gains, drooling, vomiting and diarrhea. This case report underlines risks caused by feeding of plants originally not destined as forage, if their active ingredients and effects are unknown or remain unconsidered.

Animal Feed↗
PubMed2001

[Nerve sheath tumors in cattle: literature review and case report].

Incidence, clinical signs, pathomorphological findings, differential diagnosis and prognosis of bovine nerve sheath tumours are reviewed. Own clinical and pathomorphological findings are described in an eight years old cow with a benign SCHWANNoma of the eight spinal nerve.

Animals↗
PubMed2000

[Enzootic ulcer in the back of the tongue in cattle after ingestion of hay containing flower clusters of yellow bristle-grass].

Chronically recidivating enzootic ulcerations in the tongues of numerous milking cows in the Po river plain area in Italy. The animals were permanently kept indoors in cubicle houses and fed by hay containing high amounts of ripe yellow bristle grass (Setaria glauca (L.) Beauv. [= S. pumila Poiret]). The panicled parts of the culms were found to be the cause of the massive injuries.

Animal Feed↗
PubMed1999

New insights in the bronchodilatory and anti-inflammatory mechanisms of action of theophylline.

Phosphodiesterase (PDE) inhibition and adenosine antagonism have been identified as important underlying mechanisms for the bronchodilating and anti-inflammatory action of theophylline (CAS 58-55-9). The aim of the present study was to determine the effects of PDE inhibition by theophylline on cAMP and arachidonic acid (AA) metabolism, namely leukotriene B4 (LTB4) and prostaglandin E2 (PGE2) production, in cultured monocytes in vitro. Monocytes obtained from healthy non-smoking subjects were incubated in adherence at 37 degrees C for 4 h in the presence of theophylline (0.18, 1.8 and 18 micrograms/ml, respectively) and stimulated with LPS (10 micrograms/ml). LTB4, PGE2 and cAMP were measured in the same culture supernatants by direct enzyme immunoassay. LPS-stimulated generation of cAMP increased significantly (+162%) in the presence of theophylline (18 micrograms/ml); production of LTB4 was suppressed (-42%) compared to the baseline, whereas PGE2 production increased significantly (+39%). Production of cAMP correlated with increased PGE2 production (r = 0.73, p = 0.025) and with suppression of LTB4 (r = 0.67, p = 0.016). These effects were mimicked by cell permeant nucleotides, such as dibutyryl-cAMP but not by dibutyryl-cGMP and could be abolished by ibuprofen. These results provide the first evidence that the clinical efficacy of theophylline may result from inhibition of leukotriene production and its capacity to stimulate PGE2 production. The underlying mechanism is suggested as feedback regulatory induction of COX-2 by a prostaglandin driven cAMP-mediated process.

Adult↗
PubMed1999

Reproterol--A monomolecular combination of orciprenaline and theophylline: novel aspects of its mode of action in asthma.

BACKGROUND AND OBJECTIVE: Reproterol is a monomolecular combination of orciprenaline and theophylline used as beta-adrenergic agonist to induce bronchodilation in bronchial asthma. Since the mechanism of action of reproterol has not been investigated so far, its potential anti-inflammatory activity in asthma remains still unknown. Therefore, we have studied in vitro whether the theophylline component of the reproterol molecule might enhance the stimulatory effect of the beta-adrenoceptor on cAMP production resulting in suppression of inflammatory mediator production. METHODS: The effects of reproterol, orciprenaline and theophylline (10(-9)-10(-5) M) on spontaneous cAMP (5 x 10(4) cells/30 min)- and on LPS (10 microg/ml)-stimulated LTB4 production (10(5) cells/4 h) were determined in normal monocytes in vitro. RESULTS: Production of cAMP (n = 9) was significantly augmented in a dose-dependent manner by orciprenaline (30 +/- 8%) and theophylline (28 +/- 10%), but mostly by reproterol (127 +/- 8%) at 10(-5) M. Despite incubation with propranolol, significant stimulation of cAMP production was notable following reproterol therapy. Production of LTB4 was significantly inhibited by reproterol (-48 +/- 14%) and less by theophylline (-28 +/- 10%), but was stimulated by orciprenaline (+20 +/- 8%) at 10(-5) M. CONCLUSION: We conclude that reproterol exerts a strong stimulatory effect on monocyte cAMP production and a suppressive effect on LTB4 production possibly due to a synergistic mode of action on adenylate cyclase activity and inhibition of phosphodiesterases. More clinical studies in bronchial asthma will be needed to determine whether these results may translate into clinically relevant effects.

Adrenergic beta-Agonists↗
PubMed1999

[Borna disease in cattle (consensus report)].

Short survey on definition, occurrence, cause, importance, pathogenesis, clinical findings, course, postmortal lesions, treatment, prevention and eradication of Borna disease in cattle.

Animals↗
PubMed1998

The anti-inflammatory activity of L-menthol compared to mint oil in human monocytes in vitro: a novel perspective for its therapeutic use in inflammatory diseases.

The anti-inflammatory efficacy of monoterpenes is still unknown. In order to evaluate the potential role of L-menthol and mint oil as an anti-inflammatory drug, preclinical in vitro-investigations were performed using LPS-stimulated monocytes from healthy volunteers. Arachidonic acid metabolism was assessed by measuring LTB subset4 and PGE subset2 as indicators for both the lipoxygenase and the cyclooxygenase pathways respectively. In addition, the anti-inflammatory effects of the two terpenes on IL-1beta production were analysed. - L-menthol significantly suppressed the production of each of the three inflammation mediators by monocytes in vitro. LTB subset4 decreased by -64.4 +/- 10%, PGE subset2 by -56.6 +/- 8%, and IL-1beta by -64.2 +/- 7% respectively at L-menthol concentrations within the presumed therapeutic range of about 10 superset-7 g/ml. In contrast, mint oil had a bimodal effect on PGE subset2 production: lower concentrations of 10 superset-10 to 10 superset-8 g/ml increased PGE subset2 up to 6-fold compared to baseline but concentrations of 10 superset-7 g/ml suppressed PGE subset2 production by approximately 50%. Mint oil had similar effects on LTB subset4 and IL-1beta as its main constituent, L-menthol, although the degree of suppression was by comparison smaller at lower concentrations. Paraffin oil, which served as a solvent, did not affect arachidonic acid metabolism and IL-1beta production. - These results obtained with human monocytes suggest preferable anti-inflammatory effects of L-menthol compared to mint oil at therapeutically relevant concentrations supplied in enteric coated capsules. Therefore, clinical trials investigating the potential therapeutic efficacy of L-menthol for treatment of chronic inflammatory disorders such as bronchial asthma, colitis and allergic rhinitis seem worthwhile.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1998

Inhibition of cytokine production and arachidonic acid metabolism by eucalyptol (1.8-cineole) in human blood monocytes in vitro.

Cineole (eucalyptol) is the isolated active agent of eucalyptus oil. Traditionally, it is recommended for treating the symptoms of airway diseases exacerbated by infection. We have examined the inhibitory effect of 1.8-cineole on LPS-and IL1beta-stimulated mediator production by human monocytes in vitro. For the first time, we report on a dose-dependent and highly significant inhibition of production of tumor necrosis factor-alpha, interleukin-1beta, leukotriene B4 and thromboxane B2 by 1.8-cineole. In summary, this is the first report on a new mechanism of action of monoterpenes suggesting 1.8-cineole as a strong inhibitor of cytokines that might be suitable for longterm treatment of airway inflammation in bronchial asthma and other steroid-sensitive disorders.

Adult↗
PubMed1998

Antiinflammatory effects of euclyptol (1.8-cineole) in bronchial asthma: inhibition of arachidonic acid metabolism in human blood monocytes ex vivo.

Monoterpenes are prescribed to treat chronic obstructive airway disorders mainly because of their familiar secretolytic properties. The aim of this study was to investigate the effect of 1.8-cineole (Soledum) on arachidonic acid (AA) metabolism in blood monocytes of patients with bronchial asthma. Patients with bronchial asthma (n = 10) and healthy test subjects (n = 12) were included in the study. Production of the representative AA-metabolites LTB4 and PGE2 from isolated monocytes stimulated with the calcium ionophore A23187 were measured ex vivo before therapy with 1.8-cineole (3 x 200 mg/day), after three days of treatment (day 4) and four days after discontinuation of 1. 8-cineole (day 8). The production of LTB4 and PGE2 from monocytes ex vivo was significantly inhibited on day 4 in patients with bronchial asthma (-40.3%, n = 10 and -31.3%, p = 0.1, n = 3 respectively) as well as in healthy volunteers (-57.9%, n = 12 and -42.7%, n = 8 respectively). In conclusion, 1.8-cineole was shown to inhibit LTB4 and PGE2, both pathways of AA-metabolism. Further studies are needed to show that 1.8-cineole is suitable in the treatment of bronchial asthma.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1996

An improved DNA test for bovine leucocyte adhesion deficiency.

A modified DNA test, based on the polymerase chain reaction, was developed for the monogenic recessive disease bovine leucocyte adhesion deficiency (BLAD). The test was improved by the selection of new primers which facilitated the interpretation of the results. An easily scorable banding pattern makes the test useful in cattle breeding schemes and for clinical diagnosis. A total of 2381 samples was analysed over a period of three years. The carrier rate among young bulls at artificial insemination (AI) stations decreased from 11.6 per cent in 1993 to 9.9 per cent in the first five months of 1995. Continuous screening of young bulls before entering AI is still recommended unless both parents are proven to be genetically free of BLAD. The carrier rate among clinically suspect animals was not increased, and carriers are therefore not expected to be immunodeficient. Despite all efforts to eradicate the disease, calves with BLAD were still observed in 1995.

Animals↗
PubMed1994

[Bovine leukocyte adhesion deficiency: clinical picture and differential diagnosis].

The pathological clinical and laboratory findings obtained in 50 calves and young cattle affected with Bovine Leukocyte Adhesion Deficiency are compared with those found in 114 calves and young cattle showing marked neutrophil leukocytosis of other origin (age: < 2 years; leukocyte count: > 30,000 per microl; percentage of lymphocytes: < 55%).

Animals↗
PubMed1992

[The effect of seasonal undernutrition on the protein fractions in the blood of Moroccan cattle].

In a trial including 84 cattle from three farms near Rabat (Morocco) the influence of undernutrition (dry season September to February) on the concentration of total protein and its fractions in the blood of cattle was investigated. The results out of the field were confirmed by comparing these concentrations during an experimental cycle of sufficient--insufficient--sufficient feed. It was obvious that malnutrition decreases the concentration of total protein and some of its fractions (albumins, gamma-globulins) in the blood by about 10%, while alpha- and beta-globulins remained nearly uneffected.

Animals↗