PubMed Health⌕ Search

Biomedical subjects

C Baumgarten

Publications and source records attributed to C Baumgarten.

At least 19 recordsLinked to original sources
PubMed1992

Effects of converting enzyme inhibition on endothelial bradykinin metabolism and endothelium-dependent vascular relaxation.

The effects of ACE-inhibitors on bradykinin metabolism and bradykinin-induced endothelium-dependent relaxation were studied in isolated coronary arteries and endothelial cells in culture. The results suggest that ACE-inhibitors affect coronary vascular tone by at least two endothelium-dependent and bradykinin-mediated mechanisms: First, ACE-inhibitors decrease endothelial bradykinin degredation which is accompanied by an augmented bradykinin mediated endothelium-dependent relaxation. Second, ACE-inhibitors evoke endothelium-dependent relaxations in coronary arteries stimulated with threshold concentrations of bradykinin, which cannot be attributed to an inhibition of bradykinin degradation. The effect appears to represent a new mechanism which may be based on an interaction of the bradykinin receptor and the angiotensin converting enzyme on the cellular level.

Angiotensin-Converting Enzyme Inhibitors↗
PubMed1991

Plasma exudation as a first line respiratory mucosal defence.

A great variety of provocations of the airway mucosa produce extravasation of plasma from the abundant subepithelial microvessels. A plasma exudate has important actions through its volume, its specific and unspecific binding proteins, its enzyme systems, and its potent peptides (of kinin, complement, coagulation, fibrinolysis and other systems). If allowed to operate on the surface of an intact mucosa the plasma exudate would have important roles in normal airway defence. Recent observations in guinea-pig tracheobronchial airways and in human nasal airways suggest that the mucosal exudation of plasma into the airway lumen is a non-injurious fully reversible process. Threshold exudative responses thus resulted in the appearance of an 'unfiltered' plasma exudate not only in the lamina propria but also on the surface of an undisrupted mucosa. Even after extensive luminal entry of exudate the epithelial lining was intact, as judged by light, fluorescence and electron microscopy. Hence, the epithelial barrier was reversibly permeable when approached from beneath by the plasma exudate. This was a distinct increase in outward permeability, because even during the exudation of plasma the mucosa remained a barrier to luminal solutes. It is possible that the exudate itself, by a slight compressive action on the basolateral aspect of epithelial cells, creates intercellular pathways for its entry into the lumen. Contrary to current beliefs, we propose that plasma exudation should be considered a first line respiratory defence mechanism operating together with other systems of the mucosal surface.

Absorption↗
PubMed1991

Suppressive effect of loratadine on allergen-induced histamine release in the nose.

It has been speculated whether the recently developed non-sedating antihistamines may possess other properties than merely being antagonists at the H1-receptors. To investigate this suggestion 12 patients with strictly seasonal allergic rhinitis participated in a double-blind placebo controlled randomized cross-over study outside the pollen season. At steady state levels of 10 mg loratadine, a new non-sedating antihistamine, the patients were challenged with methacholine. This was followed by a nasal challenge with increasing doses of allergen. 24 h later the patients were rechallenged nasally with the same methacholine dose as the day before. The volume of the methacholine-induced nasal secretion was measured and the response to allergen was determined by scoring technique. In returned nasal lavage fluid the levels of histamine and TAME-esterase activity were measured. It was found that loratadine significantly reduced the immediate allergic nasal symptoms compared with placebo (P less than 0.01). Loratadine also reduced the allergen-induced release of histamine into the nasal cavity after the strongest allergen dose, from 9.6 +/- 1.5 (mean +/- SEM) to 6.4 +/- 1.4 ng/ml (P less than 0.05). A similar decrease in the TAME-esterase activity after treatment with loratadine was observed. The TAME-esterase activity decreased from 11.6 *10(3) +/- 2.47 *10(3) to 5.60 *10(3) +/- 1.45 *10(3) CMP (P less than 0.05). There were no significant changes between the active and placebo treatments regarding the methacholine-induced secretory response. This was true for the initial methacholine challenge as well as the secretory response 24 h later.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1991

Presence of vasoactive intestinal peptide receptors in nasal mucosa.

In recent years several tachykinins have been identified in the airway sensory nerves. Since the physiological and pathophysiological effects of neuropeptides depend on their functionally relevant concentrations and presence of specific receptors in the target tissue, specimens of enlarged turbinates and nasal polyps were removed in 11 patients and examined for the presence of vasoactive intestinal peptide (VIP) receptors. An intensive color reaction was observed in the cytoplasm of the tubular mucosa cells in polyps and turbinates as well as in the epithelium and submucosal glands. Since both these tissues reacted with VIP receptor antibody, noncross-reacting antibody against dendritic reticular cells (DRC 6-B7), nonspecific binding is possible, however it also must be speculated that the unspecific binding is overlaying specific binding. In addition a large number of cells located diffusely or in close association in the subepithelium and interstitial tissue stained only with VIP-specific antibody, indicating specific receptor binding. The color reaction is limited to the cell membrane and the cytoplasm of these cells was clearly eosinophilic. These cells were located in close proximity of the blood vessels, very indicative for active migration. Since VIP-positive nerves are also located near the blood vessels an activation process of these cells with subsequent release of enzymes and other active proteins is possible, thus influencing the inflammatory response.

Adult↗
PubMed1991

The possible role of substance P in the allergic reaction, based on two different provocation models.

It was shown in two different provocation models (nasal and bronchial provocation) that substance P (SP) may play an important role in the neurogenic inflammatory response in upper and lower airway disease. (1) Pretreatment with SP augments the antigen challenge response of the nasal mucosa. (2) The baseline bronchoalveolar lavage (BAL) concentrations of SP are elevated 8-fold in allergies (pollen asthma) as compared with normals, even outside of season. (3) The SP concentration in BAL increases significantly (p less than 0.05) after bronchial allergen provocation. These findings support a previous hypothesis of an abnormally elevated activity of nonadrenergic-noncholinergic excitatory nerves and are in accordance with the results of a decreased activity of neutral endopeptidase exaggerating neurogenic inflammatory responses in the airways, including bronchomotor tone hyperresponsiveness.

Adult↗
PubMed1985

Mediator release during nasal provocation. A model to investigate the pathophysiology of rhinitis.

The pathogenesis of rhinitis was investigated using a model of nasal provocation with different types of stimuli. Allergic subjects had an immediate response to antigenic challenge with symptoms of rhinitis highly correlated with increments in the concentrations of histamine, prostaglandin D2, kinins and kininogens, leukotrienes, and toluene sulfonyl arginine methyl ester esterase activity in their nasal secretions. This reaction was abated by a tricyclic antihistamine also capable of inhibiting mediator release from human mast cells in vitro and, in some subjects, by disodium cromoglycate. In a number of patients, symptoms reappeared three to 12 hours after nasal provocation. This late reaction also involves release of all of the aforementioned mediators except for prostaglandin D2, and preliminary data suggest that it can be inhibited by oral or topical steroids. Cold, dry air can induce rhinitis with mast cell mediator release from selected subjects. The pathogenesis of this reaction is unclear, but there are indications that osmolarity changes are responsible for mast cell activation. Thus, mast cells can be induced to release mediators and cause nasal symptoms by both immunologic and physical mechanisms, which may account for the pathophysiology of several types of rhinitis.

Air↗
PubMed1978

The significance of nasal protease inhibitor concentrations in house dust allergy.

In 57 patients with house dust allergy and 20 controls protease inhibitor concentrations in nasal secretions were measured before and after antigen challenge. A correlation was found between low inhibitor levels and long duration of disease. Furthermore, significant differences of inhibitor concentrations could be demonstrated between patients with strong or moderate reactions to antigen provocation, and between patients with isolated rhinitis or a combination of rhinitis and bronchial asthma. The clinical significance of the results will be discussed with special regard to different biochemical mechanisms in the pathophysiology of seasonal and perennial immediate-type rhinitis.

Adolescent↗
PubMed1976

Globin synthesis in uraemia.

Globin synthesis was measured by incubating washed packed red cells with a balanced amino acid mixture and 14C-Histidine. After globin had been isolated from the haemolysate the 14C-incorporation rate per 10 mg globin per min was estimated. With regard to globin synthesis no differences existed between patients on chronic intermittent haemodialysis therapy (n equals 41), patitents suffering from secondary anaemia due to chronic infection, rheumatism or malignant diseases (n equals 21) and healthy subjects (n equals 37). Patients with acute bleeding on the other hand, had significant higher 14C-incorporation rates caused by an increase of the reticulocyte count mu1 blood (n equals 13). When substances retained in renal failure were added to the incubation mixture a marked inhibition took place with guanidinosuccinic acid, methylguanidine and fraction containing peptides with a molecular weight between 1200-1400 present in uraemic serum and normal urine, but not in serum from patients without renal failure.

Amino Acids↗
PubMed1975

[Early postoperative diagnostic management by arterial-reobstruction after vascular operations using the ultrasonic flowmeter (author's transl)].

The Doppler ultrasonic method can confirm the success of the operation in the early post-operative phase after reconstructive vascular operations as an essential non-invasive technique or clear a doubtful improvement of the blood flow. Thus an arteriography can be indicated in good time. On the basis of reconstructive cases the usefulness and the advantageous application of the Doppler ultrasonic flowmeter in the operating theater is demonstrated.

Adolescent↗