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Biomedical subjects

H Mensing

Publications and source records attributed to H Mensing.

At least 19 recordsLinked to original sources
PubMed1992

Binding of Haemophilus ducreyi to extracellular matrix proteins.

A collection of Haemophilus ducreyi isolates were screened for the ability to bind to fibrinogen, fibronectin, collagen, gelatin and laminin by a particle agglutination test using latex beads coated with the individual proteins. Thirteen of 21 isolates reacted with all five extracellular matrix proteins. Binding of organisms to protein-coated latex beads was inhibited by pretreatment of the bacteria with detergent, trypsin or boiling. Two isolates did not bind to collagen and gelatin with one of these not reacting with laminin either. Seven strains which failed to react with laminin did not express pili when examined by electron microscopy. This observation suggests a specific interaction with the pili of H. ducreyi.

Agglutination Tests↗
PubMed1992

Lack of immunoglobulin A1 protease production by Haemophilus ducreyi.

A collection of 20 strains of Haemophilus ducreyi including freshly isolated, low-passage and multi-passage reference strains was examined for immunoglobulin A1 protease production by SDS-PAGE and immunoblotting. None of the strains demonstrated IgA1 protease activity despite the fact that different culture media were used. By direct immunofluorescence testing, binding of IgA to Haemophilus ducreyi organisms could be demonstrated.

Blotting, Western↗
PubMed1992

Binding of beta-adrenergic receptors in human skin.

Radioligand-binding experiments were performed with crude membrane homogenates (CMH) from human skin in order to investigate the epidermal beta-adrenergic receptor (beta AR) density. CMH were prepared from leftovers of split-thickness skin grafts by sequential homogenization and centrifugation procedures to yield essentially epidermal fragments. Saturation experiments with the non-selective beta-adrenoceptor antagonist (-)-[125I]-iodocyanopindolol (ICYP) as radioligand showed saturable specific binding isotherms. Scatchard transformation of the data demonstrated high-affinity binding of ICYP to a single class of beta AR (Bmax = 80 +/- 10 fmol/mg protein; KD = 8 pM +/- 0.9; n = 8). beta AR antagonists displaced ICYP in a monophasic displacement pattern. The IC50 values were (nmol/1) propranolol (non-selective) 24.8; ICI 118,551 (beta 2 selective) 14.7; CGP-12177 (non-selective) 28.9; bisoprolol (beta 1 selective) 1500; CGP-20712A (beta 1 selective) 8990. beta AR agonists displaced ICYP with a potency ranking isoprenaline greater than adrenaline greater than noradrenaline. We conclude that epidermal crude membrane homogenates prepared from human split-thickness skin contain a high population of beta 2-adrenergic receptors. These receptors may be studied to further investigate the nature of human epidermal beta-adrenergic mechanisms.

Adult↗
PubMed1992

Treatment of cutaneous lupus erythematosus with acitretin and hydroxychloroquine.

A randomized, double-blind, multicentre study was performed to compare the efficacy of acitretin (50 mg/day) with hydroxychloroquine (400 mg/day) in 28 and 30 patients, respectively, suffering from cutaneous lupus erythematosus (LE). The study was carried out over an 8-week period. Improvement of facial LE lesions after treatment with acitretin and hydroxychloroquine was assessed using several clinical parameters. In the acitretin group there was marked improvement or clearing of erythema in 10/24 patients (42%), of infiltration in 15/24 (63%) and of scaling/hyperkeratosis in 12/20 (60%). In the hydroxychloroquine group there was complete clearing or marked improvement of erythema in 17/25 patients (68%), of infiltration in 17/25 (68%) and of scaling/hyperkeratosis in 15/23 (65%). Overall improvement occurred in 13/28 patients (46%) treated with acitretin and in 15/30 patients (50%) with hydroxychloroquine. The incidence of side-effects was higher in the acitretin group, and necessitated discontinuation of treatment in four patients. The present results demonstrate that both acitretin and hydroxychloroquine provide effective treatment in approximately 50% of cases of cutaneous LE.

Acitretin↗
PubMed1992

[Psoriasis and beta-blockade].

Psoriasiform skin eruptions during treatment with beta-adrenergic blocking drugs have recently attracted increasing attention and led the Bundesgesundheitsamt [German Office of Public Health] to publish general information on this issue. Today's knowledge on the clinical picture, pharmacology, and the pathogenesis is discussed, with reference to the latest experimental data. The blockade of keratinocyte beta-adrenergic receptors may play a key role in the aetiopathology of this unwanted side-effect.

Adrenergic beta-Antagonists↗
PubMed1992

[Eosinophilia-myalgia syndrome. Clinical aspects and follow-up of 10 patients].

A retrospective study (1985-1989) of patients suffering from diffuse fasciitis with eosinophilia revealed that five of eight patients had taken L-tryptophan-containing drugs before the onset of the disease. In addition, since this drug-disease association was first described five patients have been diagnosed during the year 1990. All ten patients developed peripheral eosinophilia, myalgia and deep skin involvement indistinguishable from eosinophilic fasciitis. Corticosteroids were able to reduce the pain and inflammatory parameters, but did not prophylactically improve the long-standing sclerodermalike skin thickening. In 2/5 patients with symptoms longer than 1 year, low-dose corticosteroid maintenance therapy has been continuously required to control joint and muscle pain.

Adult↗
PubMed1992

[Bowenoid actinic keratosis: therapy with intralesional injection of recombinant beta-interferon].

Biopsy-proven bowenoid actinic keratosis located in the pretibial region in each of two elderly women (61 and 81 years) were treated with intralesional injections with a new recombinant beta-interferon. The treatment took the form of intralesional injections three times a week over 3 consecutive weeks. The dose per single injection was 1.5 or 1.0 MU interferon, respectively. Clinical and histological examinations showed a complete response in both patients. Controls up to 18 months showed no relapse. There were no flu-like side-effects. Leukocyte counts decreased by 2700 and 500 cells per microliter during therapy.

Aged↗
PubMed1991

Thioredoxin reductase activity at the surface of human primary cutaneous melanomas and their surrounding skin.

Plasma membrane-associated thioredoxin reductase activities have been determined on primary melanoma tissues and their surrounding skin in 29 patients. Compared to patient's normal skin, enzyme activities in melanoma were higher in some patients (n = 24) and lower in others (n = 5). Those melanomas with high TR activities yielded low activities in the adjacent epidermis, reaching normal activity 3 to 5 cm away from each primary site (n = 4). Tumors with low activities showed higher than normal activities on the immediate surrounding skin (i.e., 1 cm away from the tumor) compared to the normal skin (n = 3). Earlier it was shown that in both keratinocytes and melanoma cells, calcium regulates thioredoxin reductase activity by an allosteric mechanism. The differences in TR activities within the high and low groups may be caused by a calcium flux between the primary tumor and the surrounding epidermis, and vice versa. A comparison of TR activities to tumor invasiveness (Breslow level) in 28 primary melanomas showed a significant correlation using regression analysis (p = 0.031). A 4-fold difference in TR activity corresponds to a one-unit change in Breslow determination. These preliminary results suggest that TR activity may be another useful and sensitive assay for melanoma spread.

Biomarkers, Tumor↗
PubMed1991

High density of beta 2-adrenoceptors in a human keratinocyte cell line with complete epidermal differentiation capacity (HaCaT).

A non-tumorigenic keratinocyte cell line with complete epidermal differentiation capacity (HaCaT) was used in radioligand binding experiments to determine the number of beta-adrenoceptors. Intact cells were saturated with 3H-labelled (-)CGP-12177 (CGP), a hydrophilic non-selective beta-adrenergic antagonist as radioligand. In order to investigate the beta-adrenergic subtype selectivity, displacement experiments were performed with different antagonists and agonists. Binding of CGP to keratinocytes has been shown to be reversible and saturable and to have high affinity (Bmax = 114.0 +/- 8.8 fmol/10(7) cells with 6866 receptors/cell, KD = 0.095 +/- 0.017 nmol/l; n = 11). Beta-adrenergic antagonists inhibited binding yielding monophasic displacement curves. IC50-values (nmol/l) were: propranolol (non-selective) 1.68; CGP-12177 (non-selective) 1.08; ICI 118,551 (beta 2-selective) 2.92; bisoprolol (beta 1-selective) 1230; and CGP-20712 (beta 1-selective) 24,980. Agonists displaced CGP in the order isoprenaline greater than adrenaline greater than noradrenaline. We conclude that HaCaT cells express a high density of beta2-adrenoceptors providing a good model system to study adrenergic receptor mechanisms under reproducible experimental conditions in keratinocytes.

Binding, Competitive↗
PubMed1991

Local treatment of cutaneous and subcutaneous metastatic malignant melanoma with fotemustine.

Fotemustine is a highly reactive chloroethyl-nitrosourea anti-tumor drug that is currently undergoing phase III clinical trials in stage IV metastatic malignant melanoma. The drug is a potent alkylating agent and rapidly chloroethylates the active sites of the important thioproteins thioredoxin reductase (TR), glutathione reductase (GR) and ribonucleotide reductase (RR). These enzymes control ribonucleotide reduction and, consequently, DNA synthesis in the S phase of the cell cycle. Side effects are minor due to the rapid metabolism of the drug. [14C]Fotemustine exhibited a half-life of 90 min in the vascular system after the administration of 100 mg/m2. Fotemustine was shown to yield the volatile degradation product acetylene (a) in distilled water (4.1%/h), (b) in melanoma cell culture medium (MCDB) supplemented with 10% fetal calf serum (33%/h) and (c) in fotemustine-sensitive human melanoma cells in culture medium (70.5%/h). Due to its rapid metabolism and its low toxicity, high concentrations of fotemustine (55 x 10(-3) M) were injected directly into cutaneous and subcutaneous melanoma metastases (n = 36) of seven patients, resulting in minor necrosis followed by total remission of the metastases. Untreated metastases adjacent to the treated tumors were not affected by fotemustine, confirming that rapid local metabolism of this drug occurs only in the vicinity of injected tumors without producing any systemic effects.

Adult↗
PubMed1991

Constitutively increased micronuclei are predominantly caused by acentric fragments.

The frequency of kinetochore (centromere)-positive micronuclei (MN) was determined in 32 fibroblast cell lines. We tested 16 probands with spontaneously high MN levels (greater than or equal to 20 MN/500 cells (4%] and 8 probands (controls) with low MN levels (less than or equal to 13 MN/500 cells (2.6%]. To study whether the elevation of MN levels is due to increased chromosomal breakage we used the antikinetochore antibody fluorescent staining method. Probands with spontaneously high MN had kinetochore-positive MN increased by a factor 2.1 compared to the controls whereas the kinetochore-negative MN were increased by a factor 6.14. This shows that spontaneous elevation of MN is mainly caused by increased chromosomal breakage and only in a minor proportion by chromosome segregation errors as a consequence of spindle defects.

Adult↗
PubMed1991

A double-blind, multicenter comparison between 0.05% halobetasol propionate ointment and 0.05% betamethasone dipropionate ointment in chronic plaque psoriasis.

In a double-blind, parallel-group, multicenter comparative trial on 104 evaluable patients with severe, localized plaque psoriasis, 0.05% halobetasol propionate ointment demonstrated an 88.7% success rate assessed as "healed" or "marked improvement" compared with 78.5% for 0.05% betamethasone dipropionate ointment. Healing was observed within 24 days of the start of treatment in 40% and 25% of the patients who received halobetasol propionate and betamethasone dipropionate ointments, respectively. After 4 weeks' treatment, tolerability of both ointments was good. Neither skin atrophy nor systemic adverse effects were observed. Patient acceptance of halobetasol propionate ointment, based on cosmetic acceptability and ease of application, was significantly better (p = 0.02) than that of betamethasone dipropionate ointment.

Administration, Topical↗
PubMed1991

Acute febrile neutrophilic dermatosis (Sweet's syndrome) caused by minocycline.

Sweet's syndrome (acute febrile neutrophilic dermatosis) occurred in a 29-year-old woman with acne. Although Sweet's syndrome initially seemed to be triggered by an acute acne flare, minocycline could later be identified as the causal agent. Because this could be confirmed in an oral provocation test, this seems to be the first case of a true connection between Sweet's syndrome and its induction by a drug, namely minocycline.

Acne Vulgaris↗