PubMed Health⌕ Search

Biomedical subjects

B Scher

Publications and source records attributed to B Scher.

4 recordsLinked to original sources
PubMed2004

[PET-CT interventional tumour therapy].

Multifocal metastatic spread of solid tumours is often a diagnostic and therapeutic challenge. Those patients often cannot undergo curative surgery. Since several years, various types of interventional tumour therapy have been introduced, which may represent a promising option in those cases. In some cases morphological imaging is not able to assess the viability of a previously treated lesion. The combination of computed tomography and positron emission tomography has the potential to ease planning and guiding of interventional procedures and to improve postinterventional control. Due to its higher sensitivity and specificity, PET/CT enables for a more precise selection of patients for interventional tumor therapy. The success of a particular therapy could be assessed with greater accuracy using PET/CT as compared with the separate modalities. PET/CT was also able to improve planning and guiding interventional therapy. As of yet, no data are available concerning the success rate and long-term survival of PET/CT associated interventional procedures.

Adult↗
PubMed1976

Purification and properties of a manganese-stimulated endonuclease from Bacillus subtilis.

An endonuclease stimulated by manganese or calcium ions was isolated from Bacillus subtilis. This enzyme attacked double- or single-stranded deoxyribonucleic acid from a variety of sources, including B. subtilis, and was purified from the material released into the medium during protoplast formation. The enzyme appeared as a single peak after glycerol gradient centrifugation and comprised approximately 30 to 35% of the protein in the most purified preparations, as estimated by gel electrophoresis. It had a molecular weight of about 46,000. The mode of action of the enzyme was endonucleolytic, and circular deoxyribonucleic acid was readily cleaved. The enzyme introduced a limited number of both double- and single-strand breaks into native deoxyribonucleic acid, generally yielding products of 1 X 10(6) daltons or more in size. The reasons for this limitation of cleavage were not clear. The activity of the enzyme was inhibited by low levels of Cu2+, Co2+, Hg2+, and Zn2+. It was also inhibited by high concentrations of NaCl. A role for this enzyme in bacterial transormation is suggested.

Bacillus subtilis↗
PubMed1973

Fate of transforming deoxyribonucleic acid after uptake by competent Bacillus subtilis: phenotypic characterization of radiation-sensitive recombination-deficient mutants.

A collection of 16 isogenic recombination-deficient strains of Bacillus subtilis isolated on the basis of sensitivity to methyl methane sulfonate (MMS) or mitomycin C (MC) were characterized phenotypically. All were found to be somewhat sensitive to ultraviolet irradiation, MC, and MMS. The mutants were all blocked in "late" steps in the transformation process and were provisionally grouped into four categories on the basis of the various properties examined. Class I mutants were deficient in transformation and heterologous transduction with phage PBS1 but were transducible with homologous donors at nearly the wild-type frequency. They were blocked in donor-recipient complex (DRC) formation but formed essentially normal amounts of double-strand fragments (DSF) and single-strand fragments (SSF). The class IIa strain was deficient in transformation and PBS1 transduction, and formed DRC which was normal by all available physical and biological criteria. Class IIb mutants were deficient in transformation and PBS1 transduction, and failed to form DRC. They did produce DSF and SSF. Class III mutants were deficient in transformation, were normal in PBS1 transduction, and formed DRC which was physically indistinguishable from that of the Rec(+) parent although with slightly lowered donor-type transforming activity. Class IV strains were deficient in PBS1 transduction but were transformed at nearly the wild-type efficiency. None of the mutant strains was deficient in the adenosine triphosphate-dependent deoxyribonuclease.

Alkanesulfonates↗