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O Peter

Publications and source records attributed to O Peter.

18 recordsLinked to original sources
PubMed2004

Guidelines for the diagnosis of tick-borne bacterial diseases in Europe.

Ticks are obligate haematophagous acarines that parasitise every class of vertebrate (including man) and have a worldwide distribution. An increasing awareness of tick-borne diseases among clinicians and scientific researchers has led to the recent description of a number of emerging tick-borne bacterial diseases. Since the identification of Borrelia burgdorferi as the agent of Lyme disease in 1982, 11 tick-borne human bacterial pathogens have been described in Europe. Aetiological diagnosis of tick-transmitted diseases is often difficult and relies on specialised laboratories using very specific tools. Interpretation of laboratory data is very important in order to establish the diagnosis. These guidelines aim to help clinicians and microbiologists in diagnosing infection transmitted by tick bites and to provide the scientific and medical community with a better understanding of these infectious diseases.

Animals↗
PubMed2000

[Erythema migrans with multiple lesions].

INTRODUCTION: Erythema migrans with multiple lesions is observed in Europe in only 5-20 p. 100 of Borrelia infections. The number of lesions observed simultaneously in one patient is less than 7, considering all the cases published in the literature to date. CASE REPORTS: We report three patients who presented multiple macular, erythematous and centrifugal lesions localized on the trunk and the limbs. The first patient presented about thirty lesions, the second more than seventy, and the third about twenty. Serology investigation and immunoblots allowed to establish the diagnosis of a recent Borrelia Burgdorferi infection, with multiples lesions of erythema migrans. PCR performed on a skin biopsy of one of the patients confirmed the presence of Borrelia burgdorferi. Response to antibiotic therapy was immediate in all 3 patients. DISCUSSION: These 3 cases are of particular interest because the number of simultaneous lesions is much higher than what is reported in the European literature. These observations remind the clinician that the diagnosis of erythema migrans with multiple lesions should be included, in Europe as well, in the differential diagnosis of multiple annular dermatoses.

Adult↗
PubMed1998

Rheumatic manifestations related to acrodermatitis chronica atrophicans. A review of four cases.

BACKGROUND: Acrodermatitis chronica atrophicans is a delayed manifestation of Lyme disease caused by a Borrelia burgdorferi subspecies, B. afzelii. Although rheumatic manifestations are rare, they can result in deformities of the fingers and toes if they are not treated promptly. METHODS: We report four cases of acrodermatitis chronica atrophicans seen over a 15-year period. RESULTS: Two patients had a noninflammatory unilateral knee effusion and one had swelling of the dorsum of one hand. Antimicrobial therapy was followed by a full recovery in the three patients who received an early diagnosis. The remaining patient, a 63-year-old woman, had swelling and dysesthesia in the fingers of both hands. She developed finger deformities over a period of two years. Although the swelling resolved under antimicrobial therapy, she had persistent reducible deformities of the fingers consistent with Jaccoud's arthropathy. CONCLUSION: The diagnosis of acrodermatitis chronica atrophicans rests on a history of a tick bite, a suggestive skin biopsy histology and a positive Western blot for B. afzelii. A positive response to antimicrobial therapy is also required. Acrodermatitis chronica atrophicans, a common condition in central and northern Europe, can cause joint manifestations and persistent finger deformities in the absence of early treatment.

Acrodermatitis↗
PubMed1997

pangolin encodes a Lef-1 homologue that acts downstream of Armadillo to transduce the Wingless signal in Drosophila.

Members of the Wnt/Wingless (Wg) family of signalling proteins organize many aspects of animal development by regulating the expression of particular target genes in responding cells. Recent biochemical studies indicate that the vertebrate HMG-domain proteins Lef-1 and XTcf-3 can physically interact with beta-catenin, a homologue of Drosophila Armadillo (Arm), the most downstream component known in the Wnt signal transduction pathway. However, these studies do not address whether the endogenous Lef/Tcf family members are required in vivo to transduce Wnt signals. Using genetic methods in Drosophila, we define a new segment polarity gene, pangolin (pan), and show that its product is required in vivo for Wg signal transduction in embryos and in developing adult tissues. In addition, we show that pan encodes a Lef/Tcf homologue and provide evidence that its protein product binds to the beta-catenin homologue Armadillo in vivo. Finally, we demonstrate that Pan functions downstream of Arm to transduce the Wg signal. Thus, our results indicate that Pan is an essential component of the Wg transduction pathway and suggest that it acts directly to regulate gene transcription in response to Wg signalling.

Amino Acid Sequence↗
PubMed1997

Characterization of Borrelia lusitaniae sp. nov. by 16S ribosomal DNA sequence analysis.

We determined the complete sequence of the rrs gene from five strains of genomic species PotiB2. Both distance and parsimony methods were used to infer the evolutionary relationships of the rrs gene sequence of this genomic species in comparison with the rrs gene sequence of Borrelia valaisiana and the rrs gene sequences of Borrelia burgdorferi sensu lato species obtained from sequence databases. The phylogenetic analysis revealed that the genomic species PotiB2 strains clustered in a separate lineage, which was consistent with data from previous DNA-DNA hybridization experiments (D. Postic, M. V. Assous, P. A. D. Grimont, and G. Baranton, Int. J. Syst. Bacteriol. 44:743-752, 1994). A PCR-restriction fragment length polymorphism analysis was used to identify genomic species PotiB2 and to differentiate it from B. burgdorferi sensu lato species. Moreover, signature nucleotide positions were identified for each B. burgdorferi sensu lato species. In accordance with DNA relatedness values, our findings suggest that genomic species PotiB2 can be more clearly defined and identified, and we propose that it should be referred to as a new species, Borrelia lusitaniae. The type strain is PotiB2.

Bacterial Proteins↗
PubMed1997

Genetic and phenotypic analysis of Borrelia valaisiana sp. nov. (Borrelia genomic groups VS116 and M19).

To clarify the taxonomic status of two recently described Borrelia genomic groups, groups VS116 and M19, three group VS116 strains and eight group M19 strains isolated from Ixodes ricinus ticks in Switzerland, The Netherlands, and the United Kingdom were characterized. PCR-restriction fragment length polymorphism (RFLP) analysis of the 5S-23S intergenic spacer amplicon, rRNA gene restriction analysis, 16S rRNA gene sequence analysis, randomly amplified polymorphic DNA (RAPD) fingerprinting, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and immunoblotting with monoclonal antibodies were used for genetic and phenotypic analysis. The PCR-RFLP and RAPD patterns of three group VS116 strains and eight group M19 strains were identical but differed from those of Borrelia burgdorferi sensu stricto, Borrelia garinii, Borrelia afzelii, and Borrelia japonica. DNAs from all group VS116 and M19 strains yielded three fragments (6.9, 3.2, and 1.4 kb) and four fragments (2.1, 1.2, 0.8, and 0.6 kb) after digestion with EcoRV and HindIII, respectively, hybridizing with an Escherichia coli 16S + 23S cDNA probe. The SDS-PAGE protein profiles of group VS116 and M19 strains were heterogeneous. Phylogenetic analysis of the partial 16S rRNA gene sequences showed that group VS116 and M19 spirochetes were members of a Borrelia species distinct from previously characterized members of the genus Borrelia. Based on our present study and data from previous DNA-DNA hybridizations, a new Borrelia species, Borrelia valaisiana sp.nov., in the B. burgdorferi complex, is proposed. Strain VS116 is the type strain of this new species.

Bacterial Proteins↗
PubMed1995

Strain variation of Lyme disease spirochetes isolated from Ixodes ricinus ticks and rodents collected in two endemic areas in Switzerland.

The relationship among Lyme borreliosis, Borrelia genospecies, rodent reservoirs, and Ixodes ricinus L. ticks was studied in two endemic areas in Switzerland. Ear punch biopsies and sampling of internal organs were used to isolate Borrelia burgdorferi (Johnson, Schmid, Hyde, Steigerwalt and Brenner) from small mammals, Apodemus sylvaticus L., A. flavicollis Melchoir, Clethrionomys glareolus Schreber. Spirochetes were isolated from ear tissue and spleen of the rodents. Isolates were homogeneous and belonged to typing group II identified as B. afzelii (Canica, Nato, du Merle, Mazie, Baranton and Postic). Our data show that a specific association exists between B. afzelii and rodent reservoirs in European foci. Borreliae were also isolated from field-collected I. ricinus ticks from the same study areas. Proteinic and antigenic analysis indicated that more than one genospecies were present in the tick population. This suggests that other vertebrate hosts may serve as reservoirs of other Borrelia genospecies implicated with Lyme disease.

Animals↗
PubMed1993

Involvement of GABAB receptors in the regulation of the hypothalamo-pituitary-adrenocortical (HPA) axis in rats.

Previous experiments have shown that the GABAB receptor agonist L-baclofen given subcutaneously to male rats significantly enhanced plasma concentrations of adrenocorticotropic hormone (ACTH) and the adrenocortical hormones corticosterone and aldosterone. The goal of the present study was to investigate whether the stimulatory effects on adrenocortical steroids elicited by L-baclofen in vivo could be reversed by the selective GABAB antagonist CGP 35 348. One hour before subcutaneous administration of 3 mg/kg L-baclofen, a dose of 600 mg/kg CGP 35 348 or saline was administered intraperitoneally. The stimulatory effect of L-baclofen on ACTH, corticosterone and aldosterone was significantly reduced by 60% after pretreatment with CGP 35 348. The GABAB antagonist CGP 35 348 by itself had no effect on ACTH or the adrenocortical hormones. These results indicate that GABAB receptors are involved in the L-baclofen-induced activation of the HPA axis in rats. In vitro, however, neither L-baclofen nor CGP 35 348 had any effects on corticosterone and aldosterone release from perifused adrenal cells. These results suggest that the participation of GABAB receptors in the activation of the HPA axis induced by L-baclofen in vivo does not occur at the level of the adrenal gland, and therefore must occur at the level of the pituitary or the brain.

Adrenal Cortex↗
PubMed1993

Mediterranean spotted fever in Marseille, France: correlation between prevalence of hospitalized patients, seroepidemiology, and prevalence of infected ticks in three different areas.

We report the results of a comparison of several epidemiologic and ecologic parameters affecting the incidence and seroprevalence of Mediterranean spotted fever (MSF) in northern, central, and southeastern Marseille, an area endemic for this disease. In northern Marseille, the incidence of hospitalized patients with MSF was 24.2/100,000 persons compared with 9.8/100,000 and 8.8/100,000 for the central and southeastern regions, respectively. The seroprevalence in sera from blood donors, determined by microimmunofluorescence and confirmed by Western blot assays, was higher in the northern region than in the other two areas (6.7% versus 3.6% and 2.4%, respectively). This higher prevalence of MSF in the northern part of the city may be related to a greater tick exposure due to a higher number of dogs (32.6/100 inhabitants versus 28.4/100 and 27.2/100 in the central and southeastern regions, respectively) and a higher rate of infection of dogs in the northern region (51.4% versus 43.5% and 39.9%, respectively). The ratio of spotted fever group rickettsia-infected ticks was similar in both the northern and southeastern areas (14.8% and 13.4% respectively), but lower in the central area of the city (8.9%), leading to a higher risk of having MSF after a tick bite in the northern and southeastern parts of Marseille.

Adult↗
PubMed1992

Population genetic analysis of Borrelia burgdorferi isolates by multilocus enzyme electrophoresis.

Fifty Borellia burgdorferi strains isolated from humans and ticks in Europe and the United States were analyzed by multilocus enzyme electrophoresis. Eleven genetic loci were characterized on the basis of the electrophoretic mobilities of their products. Ten loci were polymorphic. The average number of alleles per locus was 5.9, with a mean genetic diversity of 0.673 among electrophoretic types (ETs). The strains were grouped into 35 ETs constituting three main divisions (I, II, and III) separated at a genetic distance greater than 0.75. Divisions I, II, and III contained 13, 6, and 16 ETs, respectively. These findings, together with previous data from DNA hybridization and restriction enzyme analysis of rRNA genes, suggest that divisions I, II, and III may represent three distinct genomic species. All three divisions contained human clinical ETs. However, in division I, which includes the ET of the type strain of B. burgdorferi, the human pathogenic ETs constituted a single clone. The ETs of division I were from west-central Europe and the United States, whereas divisions II and III contained ETs from west-central and northern Europe but not from the United States. Finally, our data show that the genetic structure of B. burgdorferi populations is clonal.

Alleles↗
PubMed1981

[Epidemiological survey in a natural focus of Rickettsia transmitted by Ixodes ricinus in Switzerland (author's transl)].

A spotted fever group Rickettsia referred to as "Swiss agent" was detected in 8.5% of Ixodes ricinus collected in a marshy forest of the Swiss plateau. This organism, in its tick vector, was found to be transmitted stadially as well as ovarially; of 433 larval, nymphal or adult ticks from 17 parental tick females, all were infected. A total of 3,612 larval I. ricinus were collected from 168 small mammals including 127 Clethrionomys glareolus, 29 Apodemus sylvaticus and flavicolis, 7 Microtus agrestis, and 5 Sorex araneus from the same forest. 143 sera were obtained from these rodents: 114 (82%) had microagglutinating antibodies to the "Swiss agent".

Animals↗
PubMed1979

[New aspects of the part of the vector played by Ixodes ricinus L. in Switzerland. Preliminary note (author's transl)].

The authors, after having recalled their recent work on Ixodes ricinus ecology, give the new results about the part played by this species in the transmission of different infectious agents in Switzerland. I. ricinus was already known to be the most important vector of the tick borne encephalitis virus, and of protozoans of the Babesia genus. In this article, we describe the existence in the hemolymphe of different I. ricinus populations, of a rickettsia species related to the RMST group (Rocky-Mountain Spotted Fever), of a trypanosome, which is close to T. theileri, and of an infectious larval form (L3) of Dipetalonema rugosicauda. An outline is suggested with the object of illustrating the functioning of a natural foci of tick encephalitis. The biological significance of the unusual presence of trypanosomes and of larval filariae in ticks is also discussed. The authors underline the fact that rickettsia, trypanosomes and filarial forms are observed for the first time in Swiss I. ricinus.

Animals↗
PubMed1979

Ixodes ricinus: vector of a hitherto undescribed spotted fever group agent in Switzerland.

A tick/rickettsial survey in various parts of Switzerland revealed the presence of a new, hitherto undescribed spotted fever group rickettsia ("Swiss agent") in up to 11.7% of I. ricinus collected off vegetation. Infection in ticks was found to be generalized with rickettsiae developing intracellularly and occasionally also intranuclearly. As a result of massive growth in ovarial tissues, including the germinative cells, the rate of transovarial and filial infection was 100%. The "Swiss agent" appears to be nonpathogenic for guinea pigs, domestic rabbits, and Swiss mice, but in male meadow voles (Microtus pennsylvanicus) it produces a microscopically detectable infection in the tunica vaginalis. The rickettsia grows well in tissue culture systems including chick embryo fibroblast, Vero, and vole tissue cells, when inoculated via yolk sac into 5-day-old hens' eggs, it kills 100% of the embryos after 5 to 7 days. Antigenic relatedness of the "Swiss agent" to rickettsiae of the spotted fever group was indicated by indirect and direct fluorescent antibody staining. Preliminary serologic typing by microimmunofluorescence and by microagglutination indicated that the "Swiss agent" differs from all prototype strains of spotted fever group rickettsiae studied so far.

Animals↗