Archaeal nucleosomes

Archaea contain histones that have primary sequences in common with eukaryal nucleosome core histones and a three-dimensional structure that is essentially only the histone fold. Here we report the results of experiments that document that archaeal histones compact DNA in vivo into structures similar to the structure formed by the histone (H3+H4)2 tetramer at the center of the eukaryal nucleosome. After formaldehyde cross-linking in vivo, these archaeal nucleosomes have been isolated from Methanobacterium thermoautotrophicum and Methanothermus fervidus, visualized by electron microscopy on plasmid and genomic DNAs, and shown by immunogold labeling, SDS/PAGE, and immunoblotting to contain archaeal histones, cross-linked into tetramers. Archaeal nucleosomes protect approximately 60 bp of DNA and multiples of approximately 60 bp from micrococcal nuclease digestion, and immunoprecipitation has demonstrated that most, but not all, M. fervidus genomic DNA sequences are associated in vivo with archaeal histones.     

Buspirone metabolite structure profile using a standard liquid chromatographic-mass spectrometric protocol

A rapid and systematic LC-MS protocol is utilized to profile buspirone metabolites. Analysis of rat bile, urine and liver S9 samples using a standard LC-MS method provides structural information for 25 metabolites. The resulting buspirone metabolite structure database contains characteristic retention time, molecular mass and MS-MS product ion information for each compound. Metabolites are categorized according to profile groups, which illustrate that substitution reactions are primarily associated with the azaspirone decane dione and pyrimidine substructures. Structures of new buspirone metabolites are reported and include the despyrimidinyl, despyrimidinylpiperazine, glucuronide, hydroxyglucuronide (four isomers), methoxyglucuronide and hydroxymethoxyglucuronide (two isomers) buspirone metabolites.     

Increased expression of stromelysin 3 mRNA in leiomyomas (uterine fibroids) compared with myometrium

We set out to validate the concept of three-dimensional (3D) angiography. We evaluated the sensitivity and the quality of morphological analysis mode possible by an experimental system for imaging cerebrovascular disease versus standard digital subtraction angiography (DSA). The system, the 3D Morphometer, is a computerised X-ray angiography unit capable of acquiring a set of two-dimensional (2D) projections during a rotation and then reconstructing a 3D volume from them. We studied 78 patients with suspected cerebrovascular disease. 3D and 2D images (standard 2D DSA performed during the same procedure), were reviewed blindly to assess detection and display of morphological characteristics of cerebrovascular diseases. We found 53 aneurysms, 22 arteriovenous malformations and two venous angiomas. On 3D angiography we detected two aneurysms we missed on 2D angiography. In 47 aneurysms on which further data were obtained during surgery or embolisation, the 3D angiography allowed more accurate analysis of the neck and surrounding vessels in cases in which the 2D angiographic findings were doubtful. Assessment of arteriovenous malformations was equivalent with both techniques. Under the conditions of our study, the technical constraints being the same for both methods, 3D angiography was superior to 2D angiography. Implementation on C-arm vascular systems is being evaluated.