Search PubMed⌕ Search

Biomedical subjects

D Abeck

Publications and source records attributed to D Abeck.

At least 145 records · Page 8Linked to original sources
PubMed1992

Atypical presentation of co-existent Haemophilus ducreyi and Treponema pallidum infection in an HIV-positive male.

A 25-year-old homosexual black male presented with asymmetrical perianal ulceration of uncertain clinical origin. Indepth microbiological examination revealed the combined presence of Haemophilus ducreyi and Treponema pallidum. The atypical clinical appearance may have been due to the changed immunological status of the host's being infected with Human Immunodeficiency Virus.

Adult↗
PubMed1992

Mechanisms of skin adherence, penetration and tissue necrosis production by Haemophilus ducreyi, the causative agent of chancroid.

Haemophilus ducreyi (H. ducreyi) strains, representing both reference strains and low-passage isolates, were investigated in terms of surface structures and enzymatic equipment. The interaction of these factors with host tissue was analysed using new in vitro- and in vivo-models. By electron microscopy studies there was no evidence of an extracellular capsule or surface appendages such as pili or flagella. Interaction of all isolates tested with the lectin Phaseolus vulgaris suggests N-acetyl-D-glucosamine units as common structural features of H. ducreyi cell envelope polysaccharide. In attachment to epithelial cells more than one hemagglutinin might be implicated as different haemagglutination patterns could be observed whereby the activity was not heat-labile, but was abolished by formaldehyde. Hydrophobic interactions might be of importance as well as strains showed a wide range of reactions from hydrophobic to hydrophilic, low hydrophobicity being more marked with the older strains. No elaboration of degradative enzymes based on the measurement of enzymatic activity using insoluble dye-protein complexes could be detected in case of H. ducreyi, using Azocoll and Remazol Brilliantblue hide powder for detection of proteolytic activity and elastinorcein for detection of elastase activity. In vitro studies using human keratinocytes and Vero cells did not show any morphological changes when incubated with H. ducreyi culture filtrates. In vivo studies with a new mouse model for H. ducreyi infection could confirm the results of the in vitro studies. Mere contact to undamaged skin both of whole cell organisms, live or heat-killed, and of culture filtrates did not lead to any reaction or even damage of mouse skin. However, when the outer epidermal layer was overcome by intradermal injection of shaved mice ulcers developed. Tissue necrosis production was not bound to live organisms as dead ones showed the same effect. There is great evidence that this tissue necrosis is associated with H. ducreyi lipopolysaccharide (LPS) because intradermal injection of purified H. ducreyi LPS lead to the same reaction pattern. For the first time a cell mediated immune response could be demonstrated in case of H. ducreyi infection as different antigen preparations of H. ducreyi isolates induced proliferation of lymphocytes isolated from healthy unexposed individuals and from a chancroid-sensitized male. In the latter case measured cell responses were much stronger. The dose-dependent phenomenon was associated with interleukin-2 production. In summary, H. ducreyi isolates do not exhibit cytotoxic effects on the epithelial cells of the skin.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Absence of extracellular enzyme activity and cytotoxicity in cell-free culture filtrates of Haemophilus ducreyi.

Ten isolates of Haemophilus ducreyi, including seven clinical isolates and three laboratory reference strains, were assessed for their ability to produce extracellular enzymes which might contribute to their pathogenicity. Protease, elastase, lecithinase, lipase or collagenase enzyme activity were not detected in culture filtrates from any of the isolates tested using either plate or spectrophotometrical assays. Furthermore, cell-free culture filtrates did not exhibit cytotoxic activity in vitro when tested using either an established tissue culture cell line (Vero) or a primary cell culture of human keratinocytes. These results suggest that extracellular products do not play a role in host invasion or production of tissue damage by H. ducreyi.

Cell-Free System↗
PubMed1991

[Isolated pemphigus vulgaris of the mouth mucosa--pemphigus test: diagnostic confirmation using direct immunofluorescence study of normal skin].

The diagnosis of oral pemphigus vulgaris (PV) without concomitant cutaneous manifestations is often complicated by difficulties in obtaining a biopsy specimen allowing histological examination and direct immunofluorescence (IF) microscopy. In this clinical study five of our patients with oral PV were investigated: biopsies were taken both from lesional oral mucous membranes and from unaffected gluteal skin for IF analysis. Identical IF results, with intercellular epidermal deposition of IgG in all and of C3 in two of the five cases, were obtained in lesional and nonlesional biopsies. Therefore, it is concluded that with current IF techniques examination of the normal skin is sufficient for the diagnosis of oral PV; thus, the often painful and difficult removal of biopsy specimens from within the affected oral cavity can be avoided. Further studies are needed to confirm the sensitivity of this method.

Adult↗
PubMed1990

Effect of iron limitation on protein composition and ultrastructure of Haemophilus ducreyi.

Protein profiles of whole cells of Haemophilus ducreyi grown in the presence or absence of the iron chelator desferal, were compared by polyacrylamide gel electrophoresis. Each of four strains produced novel proteins in the range 43-160 kDa when cultured under conditions of reduced iron availability. At some sub-inhibitory concentrations, desferal produced enhanced growth, possibly due to it functioning as an exogenous siderophore. Organisms grown under conditions of reduced iron availability ultrastructurally showed also large periplasmic spaces between cytoplasm and outer membrane.

Bacterial Proteins↗
PubMed1990

Increase of the relative frequency of penicillinase-producing Neisseria gonorrhoeae strains to more than five per cent in Munich.

The relative frequency of penicillinase-producing Neisseria gonorrhoeae strains isolated from Munich STD patients nowadays clearly exceeds five percent. Penicillin resistance is either due to the 3.2 or 4.4 Megadalton plasmid. Similar trends are reported from other European countries. Therefore, treatment with third generation cephalosporins such as ceftriaxone, cefotaxime or others is now generally advisable not only in the Far East and Central Africa but also in Central Europe.

Enoxacin↗
PubMed1990

Soluble interleukin-2 receptors in serum and urine of patients with chancroid and their response to therapy.

To investigate cell-mediated immune response in chancroid, soluble interleukin-2 receptor levels in serum and urine samples of healthy individuals and patients were measured by an enzyme-linked immunosorbent assay. Increased levels both in serum and in urine were observed in cases of Haemophilus ducreyi infection. In patients showing a prolonged incubation period, urine levels exceeded serum values. Therapy led to a reduction of elevated interleukin-2 receptor levels in serum and in urine.

Chancroid↗
PubMed1989

Plasmid content, serotypes, and antimicrobial susceptibility of Neisseria gonorrhoeae strains isolated in Munich in 1987-88.

Eighty-four strains of Neisseria gonorrhoeae isolated in Munich between January 1987 and June 1988 were characterized in terms of their plasmid content, protein I serovar and susceptibility or resistance to four antimicrobial agents. Eighty two percent of the strains belonged to serogroup 1B, the three most prevalent serovars being 1B-1, 1B-2 and 1B-6. Among the serogroup 1A strains, 1A-2 was the commonest serovar. Fourteen strains (16.7%) lacked the 2.6 Md cryptic plasmid, although two of these strains contained the conjugative gonococcal plasmid. Although some degree of resistance to penicillin and tetracycline was noted, all the strains were sensitive to spectinomycin and cefotiam.

Anti-Bacterial Agents↗
PubMed1989

One-shot treatment of uncomplicated gonorrhoea with third-generation cephalosporins with differing serum half-life. Results of a controlled trial with ceftriaxone and cefotaxime.

The highest minimum inhibitory concentrations of ceftriaxone and cefotaxime in 89 analysed Neisseria gonorrhoeae isolates amounted to 0.008 and 0.031 micrograms/ml, respectively. In a randomized controlled trial the single intramuscular injection of ceftriaxone 250 mg and cefotaxime 500 mg cured bacteriologically 35 out of 35, and 29 out of 30 patients, respectively, with uncomplicated gonorrhoea. Facing the different phenotypes of the isolates grown before and after therapy in the case of the non-cured patient within the cefotaxime treatment group, reinfection rather than failure has to be presumed. Postgonococcal urethritis occurred about as often in both groups, the percentage amounting to 24.2 and 28.6%, respectively. If side effects were noted at all, they were considered minor: 4 patients belonging to the first and 3 belonging to the second treatment group complained temporarily about pain at the injection site. Due to the data presented here, ceftriaxone and cefotaxime appear equally effective and safe when used in the dose generally preferred, irrespective of differences in in vitro activity and pharmacokinetic behaviour.

Adult↗
PubMed1989

[The etiopathogenesis of ulcus molle: current status of knowledge--approaches to future research].

Chancroid is a sexually transmitted disease characterized by genital ulceration. Although the pathology of chancroid lesions has been well described, we still know relatively little about the mechanism by which the causative agent, the bacterium Haemophilus ducreyi, produces disease. It is hoped that a better understanding of both the pathogenicity of H. ducreyi and the pathogenesis of chancroid will provide a rational basis for the development of improved strategies for the control of this disease.

Animals↗
PubMed1989

[Diagnosis and therapy of ulcus molle today. Case report and review of the literature].

Chancroid, an ulcerous disease of the genitalia caused by Haemophilus ducreyi, occurs rarely but regularly in Germany. Exact diagnosis is based on the clinical features and a direct smear, and in particular on cultivation of the organism, showing its unique macromorphological characteristics. The sensitivity of cultivation has increased due to the development of selective media for primary isolation. Resistance problems during the last decade meant that a change to new therapeutic strategies was unavoidable. The work presented here includes a case report and a review of the recent literature, it illustrates modern methods of diagnosis and treatment of Haemophilus ducreyi infections 100 years after the first description of the organism.

Administration, Topical↗
PubMed1989

[Lichen aureus zosteriformis].

A case of lichen aureus is presented, which is atypical in that a very large area was involved and there was a good response to topical fluorinated steroid therapy. Similarities to other cases reported in the literature are demonstrated.

Adult↗
PubMed1989

[Morphologic variants of genital ulcer caused by Haemophilus ducreyi].

The typical clinical picture, common variants and frequent complications of chancroid are presented in cases proven by culture. In general, the conventional view of the clinical spectrum of chancroid is substantiated. Certain types such as "chancre mou volant," however, could not be found in the present material. Their existence or association with Haemophilus ducreyi remains speculative.

Adult↗
PubMed1988

Lectin typing of Haemophilus ducreyi.

The cell wall carbohydrates of 43 strains of Haemophilus ducreyi isolated in different parts of the world were subjected to lectin analysis using commercial panels containing 14 different plant lectins of known specificity. Preliminary evidence indicated both intrastrain and inter-strain variation in cell wall carbohydrate composition. In addition, it was possible to group strains from different geographical areas by lectin agglutination patterns. Lectin typing might thus become a useful marker system for epidemiological investigation of Haemophilus ducreyi infections.

Agglutination↗
PubMed1988

Antigenic analysis of Haemophilus ducreyi by Western blotting.

Twenty-one strains of Haemophilus ducreyi were analysed by Western blotting using two antisera produced in mice. Common antigens of molecular weights 58, 46, 41, 28, 22 and 16 kDa were detected in all the strains. The antigens were protein in nature, since they could not be detected in whole-cell lysates which had been treated with proteinase K. The H. ducreyi strains showed antigenic cross-reactivity with strains of H. influenzae and H. parainfluenzae, but showed minimal or no cross-reactivity with seven other species of bacteria.

Haemophilus ducreyi↗
PubMed1988

Plasmid content and protein I serovar of non-penicillinase-producing gonococci isolated in Munich.

One hundred and twenty-four strains of non-penicillinase-producing gonococci isolated in Munich in 1986 were characterized in terms of their plasmid content and protein I serovar. Eighty-two per cent of the strains belonged to serogroup 1-B with over half belonging to either serovar 1B-2 or 1B-3. Half of the 22 serogroup 1A strains belonged to serovar 1A-2. Nineteen strains (15.3%) were found to lack the 2.6 Md cryptic plasmid although seven of these strains contained the 24.4 Md conjugative plasmid. Nine of the 105 strains which harboured the cryptic plasmid also contained the conjugative plasmid. The 19 strains which lacked the cryptic plasmid comprised 10 different serovars, indicating the heterogeneous nature of this group of organisms.

Bacterial Outer Membrane Proteins↗