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Biomedical subjects

G Zon

Publications and source records attributed to G Zon.

149 records · Page 9Linked to original sources

Determination of enantiomeric homogeneity (optical purity) of cyclophosphamide by nuclear magnetic resonance spectroscopy.

The enantiomeric homogeneity of resolved samples of the chiral anticancer drug cyclophosphamide was evaluated directly by 1H and 31P nuclear magnetic resonance spectroscopy with the use of the optically active shift reagent tris-[3-(trifluoromethylhydroxymethylene)-d-camphorato]europlum(III). These measurements, in concert with optical rotatory dispersion spectroscopy, established that, for optically pure cyclophosphamide, [alphaD] = 2.3 +/- 0.2 degrees.

Cyclophosphamide↗

Synthesis and antitumor activity of cyclophosphamide analogs. 1. Benzo annulated cyclophosphamide and related systems.

Synthesis of 2-[bis(2-chloroethyl)amino]-3,4-dihydro-2H-1,3,2-benzoxazaphosphorin 2-oxide (2), which is a benzo annulated analog of cyclophosphamide [2-bis(2-chloroethyl)aminotetrahydro-2H-1,3,2-oxazaphosphorin 2-oxide (1)], was carried out in order to test for possible increased antitumor activity relative to 1 due to the presence of an oxidatively reactive C-4 benzylic site in 2. A structural isomer of 2, 2-[bis(2-chloroethyl)amino]-1,4-dihydro-2H-3,1,2-benzoxazaphosphorin 2-oxide (3), and cognate systems 2-[bis(2-chloroethyl)amino]-1,2,3,4-tetrahydro-1,3,2-benzodiazaphosphorin 2-oxide (4) and 2-[bis(2-chloroethyl)amino]-4H-1,3,2-benzodioxaphosphorin 2-oxide (5) were also prepared for comparative purposes. In vivo antitumor evaluation in mice against L1210 lymphoid leukemia indicated no significant activity for compound 2. Compounds 3 and 4 were likewise found to be inactive and only marginal activity was exhibited by 5.

Alkalies↗

Brief overview of control of genetic expression by antisense oligonucleotides and in vivo applications. Prospects for neurobiology.

Over the past several years, the use of synthetic oligonucleotides and functional analogs thereof as a possibly general means of controlling genetic expression has received widespread attention. Following a brief overview of some of the basic principles and strategies for this approach, attention is focused here on summarizing some recent reports of in vitro and, in particular, in vivo investigations in various animal models using phosphorothioate analogs of 2'-deoxyoligonucleotides. In view of these findings, which include studies related to neurobiology, this field should find significant utility in applications of the antisense method for controlling genetic expression.

Animals↗

DNA colony hybridization method using synthetic oligonucleotides to detect enterotoxigenic Escherichia coli: collaborative study.

The genes that encode several of the enterotoxins produced by Escherichia coli have been cloned by recombinant DNA techniques. When the nucleotide sequence of these genes is determined, defined sequence oligonucleotides that include a part of these genes may be synthesized. A 22-base DNA hybridization probe was produced for each of 2 heat-stable E. coli enterotoxin (ST) genes: STH, from strains originally isolated from humans; and STP, from strains first found in pigs. For this study, 32P end-labeled DNA probes, sonicated calf thymus DNA, and 3 known and 20 unknown (10 ST-positive and 10 ST-negative) strains were sent to each of 23 collaborators. Cultures were spotted onto an agar-based medium and grown into colonies, which were transferred by blotting to cellulose filters, lysed by alkali and steam, and used for DNA colony hybridization with the ST DNA probes. Strains containing an ST gene were recognized as dark spots on an autoradiogram. Of the 460 samples analyzed, 440 (95.7%) were correctly classified by the collaborators. The method has been adopted official first action.

Enterotoxins↗