PubMed Health⌕ Search

Biomedical subjects

E Weisshaar

Publications and source records attributed to E Weisshaar.

28 records · Page 2Linked to original sources
PubMed1997

Can a serotonin type 3 (5-HT3) receptor antagonist reduce experimentally-induced itch?

BACKGROUND: Serotonin type 3 (5-HT3) receptor antagonists have been reported to be a novel therapeutic principle for the treatment of cholestatic and uremic pruritus. OBJECTIVE: To determine the antipruritic effect of a 5-HT3 receptor antagonist (tropisetron) on histamine and serotonin-induced itch under experimental conditions in comparison to native skin and after pretreatment with an orally applied antihistamine (cetirizine). METHODS: Histamine and serotonin were iontophoretically applied in 10 healthy volunteers. Wheals and flares were planimetrically evaluated. Itching and burning sensations were entered on a scale over 24 min. The examination also comprised alloknesis, elicitation of perifocal itch sensation by usually non-itching (e.g. mechanical) stimuli. RESULTS: Tropisetron did not have any significant influence on histamine-induced reactions but could significantly reduce serotonin-induced flares. Cetirizine led to a significant reduction of all histamine-induced parameters and abolished serotonin-induced wheals. CONCLUSIONS: Serotonin has an own pruritic potency and does not only act over histamine containing mast cells. The antipruritic effect of tropisetron reported in cholestatic and uremic pruritus could not be verified in healthy persons under experimental conditions.

Adult↗
PubMed1997

Experimentally induced pruritus and cutaneous reactions with topical antihistamine and local analgesics in atopic eczema.

We investigated the antipruritic effect of a 15-min application of dimethindene maleate (Fenistil gel) and other local analgesics (Optiderm, EMLA, Xylocain ointment 5%) on subsequent focal histamine stimulus (20 mC) given by iontophoresis in 12 patients suffering from acute atopic eczema (AE). The results were compared to histamine after pretreatment with the respective placebo and to non-pretreated skin. Wheal and flare areas were planimetrically evaluated. Itch or pain ratings were performed over a 24-min period using a rating scale. The examination also comprised alloknesis, i.e. induction of a perifocal itch sensation by a non-itching mechanical stimulus. None of the antihistaminic and anaesthetic agents reduced the itch intensity significantly. Three of the AE patients had a total lack of alloknesis. We conclude that these substances, when applied for 15 min, are not sufficiently effective in atopic skin suppressing histamine-induced reactions under experimental conditions. The diminished elicitation of alloknesis in these patients may be a result of central nervous system alteration.

Administration, Topical↗
PubMed1997

Atrial myxoma syndrome mimicking Ehrmann-Sneddon syndrome.

Livedo racemosa with cerebrovascular lesions has been described as Ehrmann-Sneddon syndrome. The etiopathogenetic factors provoking the vascular lesions, however, are of high diversity reaching from mechanical to autoimmune causes. We present a male patient with typical livedo racemosa, muscle pain and feeling of coldness of the forearms. By dermatohistopathology and magnetic resonance tomography of the brain, Ehrmann-Sneddon syndrome could be confirmed. At this time a chronic streptococcal infection could be diagnosed. Antibiotics, anticoagulants and vascularity-supplying therapy improved the clinical and subjective symptoms. Six months later, the patient developed dizziness, vision disorder, hypesthesia of the right forehead, malaise and weight loss. A further diagnostic workup including echocardiography revealed a myxoma of the left atrium. This report illustrates the association of Ehrmann-Sneddon syndrome with cardiac myxoma and points out that cardiac diagnostic examination should be included when dealing with small-vessel involvement of the brain.

Adult↗
PubMed1996

[Antipruritic effect of antihistaminic and local anesthetic topical agents after iontophoretic histamine stimulation].

No adequate topical therapy is available for pruritus. As little is known about the local influence of antihistamines and topical anaesthetics on the pruritic effect of histamine, we studied these agents in 12 volunteers. The antipruritic effect of 15-min topical application of dimethindene maleate (Fenistil gel) and different agents (Optiderm, EMLA, Xylocaine-Salbe 5%) on subsequent focal histamine stimulus (20 mC) given by iontophoresis was evaluated. The results were compared with those of pretreatment with the corresponding placebo creams and observations on skin. Wheal and flare areas were evaluated planimetrically. Itch or pain ratings were entered on a scale every minute over a 24-min period. The examination also comprised alloknesis, i.e. elicitation of perifocal itch sensation by usually non-itch-inducing (e.g. mechanical) stimuli. Remarkably, all topically applied substances, regardless of antihistaminic or anaesthetic potential, reduced the area of alloknesis significantly. This is likely to be a result of diminished excitability of the cutaneous mechanoreceptors. Itching was significantly reduced by all active substances, including the placebo cream corresponding to Optiderm, which might be due to the presence of urea.

Adult↗
PubMed1993

Piezoelectric shockwave lithotripters: differences in fragmentation efficiency in vitro.

In a comparative assessment of the stone fragmentation efficacy of different piezoelectric lithotripters 72 human gallstones consisting of 24 sets of 3 stones each were disintegrated in vitro using the Piezolith 2300, the EDAP LT.01, and the Therasonic. On the basis of the maximum diameter the calculi were divided into group A (6-15 mm; n = 3 x 16) and group B (16-25 mm; n = 3 x 8) and were treated by using the maximum energy setting of each lithotripter (Piezolith 2300: setting 4, high power; EDAP LT.01: 95%; Therasonic: setting 7). Shockwave application was terminated when the residual fragments measured < or = 4 mm or after a total number of 6000 pulses. With the Piezolith 2300 all calculi could be disintegrated into fragments < or = 4 mm. In contrast, fragmentation was not successful, even after 6000 applied pulses, in the case of 2 and 6 stones when using EDAP LT.01 and the Therasonic lithotripters, respectively. With the remaining concrements of group A (n = 3 x 11) the fragmentation end point was achieved after a lower number of pulses when the Piezolith 2300 (median, 250 pulses; range, 50-500 pulses) was used than with the EDAP LT.01 (1000; 150-2500; p < 0.01) and the Therasonic lithotripters (2750; 750-5500; p < 0.01). Similar results were obtained for group B (n = 3 x 6): the Piezolith 2300 required fewer pulses (200; 100-1250) than the EDAP LT.01 (1000; 500-1000; p < 0.05) and the Therasonic (2000, 500-4000; p < 0.05) units.(ABSTRACT TRUNCATED AT 250 WORDS)

Cholelithiasis↗
PubMedDate not supplied

Lack of efficacy of topical capsaicin in serotonin-induced itch.

Capsaicin (CAP) has been demonstrated to be an effective topical inhibitor of cutaneous vasodilatation, pain and pruritus induced by a variety of chemical and physical stimuli. In a previous study, we showed a significantly inhibitory effect of topical CAP treatment on histamine-induced itch and cutaneous vascular reactions in healthy subjects compared to atopic eczema patients. As serotonin is proposed to play a pathophysiological role in some types of pruritus (e.g. uremic and hepatic pruritus) and CAP has been described to be successful in hemodialysis-related pruritus, we investigated the antipruritic effect of topical CAP on serotonin-induced reactions in 10 healthy volunteers in comparison to untreated skin (UPS) and placebo substance (vehicle)-treated skin (VS). On the first day, serotonin iontophoresis was performed in untreated skin. One week later, the treatments started, using either CAP 0.05% liniment or a placebo liniment (vehicle) 3 times daily over a 5-day period. On day 6, serotonin was applied by iontophoresis within the pretreated skin. After another 1-week break, the treatments were performed vice versa on the corresponding infrascapular region. Weal and flare areas were planimetrically evaluated. Itch sensations were documentated by the volunteer on a scale over a 24-min follow-up period. The examination also comprised alloknesis, which stands for induction of perifocal sensations by usually non-itching stimuli. In CAP-treated skin, serotonin-induced wheals were significantly larger post-application compared to non-pretreated skin. Wheals were significantly larger in VS than in UPS. Comparison of serotonin-induced flares in the different study arms did not reveal any significant differences. Itch sensations were not significantly reduced by topical CAP application. The areas of alloknesis were smaller in capsaicin-treated skin compared to VS and UPS, but did not reach significant value. In conclusion, topical CAP application is not effective in serotonin-induced itching in healthy volunteers. Serotonin is most unlikely to play a role in the mechanism of action of CAP.

Administration, Topical↗
PubMedDate not supplied

Successful treatment of disseminated facial verrucae with contact immunotherapy.

Disseminated flat warts are a common therapeutic problem in immunocompromised patients. However, disseminated infection on the face is, even in the immunocompetent host, a challenge. We report on a 14-year-old girl who had suffered from increasing eruptions of multiple disseminated verrucae planae et filiformes of the face for 18 months. As an alternative to silk-touch CO2-laser, contact cryotherapy or systemic immune enhancer we administered topical immunotherapy with diphenylcyclopropenone (DCP). The initial challenge with DCP 2% was performed on the forehead and the challenge was repeated weekly with DCP 0.01%. After four applications, the girl reported peeling of single warts on the forehead but more importantly at distant sites which had not received DCP. After eight weeks the patient's face was free of lesions. So far, the patient has remained free from relapse. This is the first case report of successful topical immunotherapy with DCP in disseminated facial verrucae planae and should be regarded as an effective therapeutic tool in this indication, emphasizing the great advantage of prevention of scarring of the skin induced by other therapeutic modalities.

Administration, Topical↗