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M Maiwald

Publications and source records attributed to M Maiwald.

60 records · Page 4Linked to original sources
PubMedDate not supplied

Evaluation of the detection of Borrelia burgdorferi DNA in urine samples by polymerase chain reaction.

It is difficult in some cases to identify an infection caused by Borrelia burgdorferi and to monitor the effect of therapy. Seropositivity will persist even after successful treatment and therefore may suggest ongoing infection. For direct detection of B. burgdorferi DNA in human urine samples, the polymerase chain reaction (PCR) was evaluated. A published primer system was selected, which amplifies a 259 bp fragment from the gene encoding the 23S rRNA. The lower detection limit of the primer system was 10 fg of extracted B. burgdorferi DNA. Several methods for the pretreatment of urine samples were tested. Of these, the Geneclean kit (Bio 101, USA) showed the best results. A total of 114 urine samples from 74 patients belonging to three clinical groups was investigated: (i) 51 samples from 26 patients with active Lyme disease, (ii) 36 samples from 27 patients with previous infection but no symptoms at the time the urine was collected, and (iii) 27 samples from 21 seronegative control patients without Lyme disease. B. burgdorferi DNA was detected in 25 urine samples of 17 patients with active disease, whereas 26 samples from this group of patients were negative. Only one asymptomatic case with previous infection showed a positive result, and the urine samples of the patients without Lyme disease were uniformly negative. Two of four patients from whom samples before and directly after onset of therapy were available converted from negative to positive PCR results after initiation of therapy, accompanied by the symptoms of a Jarisch-Herxheimer reaction.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

Polymerase chain reaction-based detection of dermatophyte DNA with a fungus-specific primer system.

There is significant clinical interest in primers which are specific for fungi and do not hybridize to DNA of other eukaryotes or prokaryotes. Such primers would allow specific amplification of fungal DNA from human tissue samples containing fungi. Fungal identification to the species level could follow by direct sequencing or restriction analysis. Several previously described primer systems cross-react with DNA of plants and animals. We have designed a primer system that amplifies a fragment of the gene coding for the small ribosomal subunit 18S rRNA. Database searches and sequence analyses were performed using the HUSAR (Heidelberg Unix Sequence Analysis Resources) computer system at the German Cancer Research Centre, Heidelberg, Germany. Primers TR1 (5'-GTTTCTAGGACCGCCGTA) and TR2 (5'-CTCAAACTTCCATCGACTTG) bind to sequences which are homologous within the fungi, but differ from corresponding DNA fragments of plants and animals. The amplified fragment is 581 base pairs in length and contains variable, and therefore species-specific, regions. The DNA of Trichophyton rubrum, Trichophyton mentagrophytes, Trichophyton verrucosum, Trichophyton terrestre, Microsporum canis, Microsporum gypseum and Epidermophyton floccosum and of several yeast species was amplified by the primers, but not the DNA from 42 normal human skin samples. Furthermore, other DNA preparations from plants and animals, including those from radish, cabbage, wheat and mouse, did not show amplification reactions.

Arthrodermataceae↗
PubMedDate not supplied

Universal fungus-specific primer systems and group-specific hybridization oligonucleotides for 18S rDNA.

We designed two primer systems that amplify a fragment of the gene coding for the small ribosomal subunit (18S rRNA). A broadly reactive, yet fungus-specific, primer cocktail comprises two previously published primers, TR1 and TR2, which specifically amplify dermatophytes, and two newly designed primers, CA1 and AF2, which specifically amplify Candida and Aspergillus respectively. This primer cocktail amplifies a DNA fragment of approximately 578 basepairs (bp) in length (from position 838 to 1415), which contains variable, possibly species-specific regions (V5, partly V7). Another newly designed primer, UF1 (universal fungal primer 1), along with the eukaryotic primer S3 amplifies a 926-bp fragment (from position 263 to 1188) that includes the variable regions V3, V4 and V5. Both primer systems amplified DNA from Saccharomyces cerevisiae, Candida albicans, Cryptococcus neoformans, Aspergillus fumigatus, Penicillium marneffei, Fusarium oxysporum and Trichophyton mentagrophytes, but not the DNA from Prototheca zopfii, Escherichia coli or humans. The previously published oligonucleotides TR and HC, which are specific for dermatophytes and Histoplasma respectively, and the newly designed group-specific oligonucleotides, CA and AF, hybridized with T. mentagrophytes, Histoplasma capsulatum, C. albicans and A. fumigatus respectively, but not with the other six fungi or with the three controls.

Base Sequence↗