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Biomedical subjects

S Weston

Publications and source records attributed to S Weston.

31 records · Page 2Linked to original sources
PubMed1991

2'-O-alkyloligoribonucleotides, synthesis and applications in molecular biology.

Oligo(2'-O-alkylribonucleotides) have been synthesized in which alkyl is methyl, allyl and butyl. The various phosphoramidite monomers of 2'-O-alkyl uridine, cytidine, adenosine, guanosine, inosine and 2,6-diaminopurine riboside have been synthesized from a minimum of key intermediates. Extra protection of the lactam function in uracil and hypoxanthine proves useful. The high stability of the oligomers combined with incorporation of non-radioactive reporter groups such as fluorophores, biotin and 2,4-dinitrophenylamino (DNP) moities renders them as excellent antisense tools for studying RNA processing, for locating and visualising RNA and RNP complexes in cells, for examining splicing complexes by electron microscopy and for the affinity chromatography of RNA or RNP complexes.

Antisense Elements (Genetics)↗
PubMed1989

Bone core biopsies. Plastic or paraffin?

Plastic embedding of bone core biopsy specimens has been promoted as providing superior morphology, primarily because semi-thin sections can thereby be cut at 1-2 mu. The major disadvantages of plastic embedding are that it increases the technical load, is more expensive, and potentially has its own intrinsic problems, including difficulties in performing special stains and immunoperoxidase studies. In order to investigate the possibility that semi-thin paraffin sections may provide similar morphological results without the intrinsic disadvantages of plastic sections, we examined 45 bone core biopsy specimens that were sufficiently large to process one half in plastic and the other half in paraffin following decalcification. Both were cut at 1-2 mu. Although many plastic sections appear esthetically more pleasing, semi-thin paraffin sections of very high quality can also be obtained routinely. Additional advantages of paraffin sections were the ability to perform peroxidase studies, lower cost, less technologist time, and avoidance of problems occasionally arising with plastic, such as difficulties with impregnation or problems with polymerization. Peroxidase studies were particularly useful in patients with possible myeloma that was not overt on hematoxylin-and-eosin section and in confirming the presence or source of metastatic carcinoma. We therefore recommend the use of semi-thin (1-2 mu) paraffin sections for routine examination of bone core biopsy specimens.

Biopsy↗
PubMed1984

DNA packaging in mouse spermatids. Synthesis of protamine variants and four transition proteins.

A comparison of the protein compositions of mouse late-step spermatids and cauda epididymal sperm has revealed that the relative distribution of the two amino acid sequence variants of mouse protamine differ markedly in spermatids and sperm. Sonication-resistant spermatids contain the two variants in a ratio of 1:1, while the ratio of these two proteins in cauda epididymal sperm is approx. 2:1. Labeling studies in vivo have shown that this difference is due, in part, to an asynchrony in the time of synthesis of the two protamine variants. Both proteins are synthesized in late-step spermatids, but synthesis of the tyrosine variant in sperm chromatin begins approximately one day before synthesis of the more predominant histidine variant. Analyses of the time of synthesis of protamine and the four transition proteins in late-step spermatids allowed us to estimate the spermatid stage in which these proteins are deposited on DNA and relate these events to the onset of sonication resistance in maturing spermatids. These results indicate that: (1) synthesis and deposition of protamine begins coincident with the onset of sonication resistance in early step 12 spermatids; (2) protamine deposition is complete by mid-step 15; and (3) synthesis of the transition proteins occurs coincident with protamine synthesis.

Animals↗