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Biomedical subjects

B Maurer

Publications and source records attributed to B Maurer.

At least 55 records · Page 3Linked to original sources

Pseudomonas streptomycin resistance transposon associated with R-plasmid mobilization.

Plasmid pMG1 encodes resistance to gentamicin, streptomycin, sulfonamides, and mercuric ions and also mobilizes pRO161, a transfer-deficient plasmid derived from RP1. Upon mobilization, pRO161 acquires streptomycin resistance (Smr) and can subsequently be remobilized by pMG1 at significantly higher frequencies than pRO161 itself. Both the initial acquisition of Smr and the subsequent mobilization of the transfer-deficient plasmid are recA independent: thus, the Smr determinant appears to be located on a transposon, disignated Tn904. Tn904 transposes to a variety of other plasmids, including RP1, FP2, R388, K, pRO1600, and pBR322, and in some cases the acquisition of this transposon accompanied deletions in the target plasmid. When no deletion occurred, target plasmids gained 5.2 kilobase pairs of DNA and new restriction endonuclease cleavage sites for AvaI, BglII, PstI, SmaI, and SstI. Physical analysis of such plasmids showed that the Tn904 termini are inverted repeat DNA sequences of approximately 124 base pairs. After cloning into vector pRO1723, a single site for restriction endonuclease AvaI was identified within the Smr determinant of Tn904. In Escherichia coli, but not in Pseudomonas aeruginosa. Tn904 shows a gene dosage-dependent expression of streptomycin resistance.

DNA Transposable Elements↗

Q fever endocarditis.

Despite a worldwide distribution of Coxiella burnetii, only single cases of Q fever endocarditis have been reported outside Great Britain and Australia. We present 10 patients; five were female, only four had a history of environmental exposure, and the mitral valve was involved as commonly as the aortic stenosis, and three patients had a prosthetic valve. We confirm the importance of hepatic involvement, thrombocytopenia and hypergammaglobulinemia as diagnostic features. Diagnosis was established by finding and elevated complement-fixing antibody to Phase I C. burnetii antigen. Tetracycline, with or without lincomycin or cotrimoxazole, was used in nine patients, and one patient received cotrimoxazole as as the sole antibiotic agent. Optimal duration of therapy is unknown. In one patient, relapse followed when treatment was stopped after 18 months. Valve replacement was necessary in five patients, because of hemodynamic problems. Five patients died, and the means survival is 36 months with a range of five to 66 months. We suggest that Q fever endocarditis is frequently missed, and we recommend clinicians to consider the diagnosis in all cases of culture-negative endocarditis.

Adult↗

[Diagnostic laparotomy in Hodgkin's disease: indication, management, results (author's transl)].

Till December 31st 1976, diagnostic laparotomy was carried out in 58 patients with Hodgkin's disease. Of these, 23 cases (40%) revealed abdominal involvement. The tumor stage found by conventional diagnostics before surgical treatment had to be altered in 16 patients (27%). It had to be increased in ten and lowered in six cases. Of 13 splenic Hodgkin infiltrations twelve had not been supposed preoperatively; four out of 43 sound organs had been suspected preoperatively because of splenomegaly. Subdiaphragmatic histological findings involving a rather unfavorable prognosis were seen in nine patients (16%). In Hodgkin's disease, risk groups cannot be selected with confidence, as no definite correlation between the frequency of subdiaphragmatic affection and the primary manifestations, histology or general symptoms was observed. Since operation risk of diagnostic laparotomy is low, operable stage I-III cases with Hodgkin's disease should undergo diagnostic laparotomy prior to treatment planning.

Adolescent↗