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R N Hanson

Publications and source records attributed to R N Hanson.

63 records · Page 4Linked to original sources
PubMed1978

Synthesis and biologic distribution of radioiodinated beta-adrenergic antagonists.

Iodinated analogues 2, 7, and 8 were prepared from propranolol, practolol, and acebutolol in 30--50% yields. Radioisotopic exchange between carrier-free Na125I and the molten iodinated beta-adrenergic antagonist yielded the corresponding 125I-labeled product. The biodistribution in rats, determined at 15 and 60 min postinjection, indicated that the radioiodinated analogues of the cardioselective drugs practolol and acebutolol localized to a greater degree in the liver and heart than the analogue of propranolol. Conversely, [125I]iodopropranolol (2) was concentrated to a greater extent in the lungs than [125I]iodopractolol (7) or [125I]iodoacebutolol (8). Therefore, 123I- or 131I-labeled cardioselective beta-adrenergic antagonists, such as 7 or 8, may prove useful as radiodiagnostic agents for the external imaging of the myocardium.

Acebutolol↗
PubMed1977

Myocardial infarct imaging with technetium-labeled complexes.

Detection of acute myocardial infarction as an area of increased activity has intrigued investigators for some time. Initial attempts with 203Hg-chlormerodrin and 203Hg-fluorescein analogues were successful in man. More recently, however, successful imaging of the acute myocardial infarct has been achieved with several 99mTc complexes. A large group of radiotracers localize in acutely damaged tissue in various models of experimental infarction. From these data, a number of specific structural properties associated with infarct avidity have been identified; these include the presence of mercury and the structural configuration of the organic carrier.

Animals↗
PubMed1977

3-Hydroxy-17-aralkylmorphinans as potential opiate receptor-site-directed alkylating agents.

In an effort to develop opiate receptor-site-directed alkylating agents, a series of 3-hydroxy-17-aralkylmorphinans containing reactive groups was synthesized and tested for analgesic and opiate antagonist activity. Many of the target compounds exhibited the characteristics of agonists and, among this group, some were found to be active blockers of morphine analgesia. One of the more potent antagonists (41) was investigated further and it was found that while its action is specifically associated with opiate receptors, 41 could not be classified either as a competitive or noncompetitive antagonist in the classical sense. The duration of antagonist action in vivo of 41 and its in vitro receptor binding characteristics suggest that covalent association with opiate receptors is not not an important factor.

Alkylating Agents↗
PubMed1977

Stereochemical studies on medicinal agents. 23. Synthesis and biological evaluation of 6-amino derivatives of naloxone and naltrexone.

Epimeric 6-amino derivatives of naloxone and naltrexone have been synthesized and the configuration at the C-6 chiral center was determined from NMR studies. All of the derivatives possess narcotic antagonist activity in mice, with each of the 6beta epimers having greater potency than the corresponding 6alpha epimers. In vitro binding experiments indicate that the affinities of these epimers parallel thier in vivo potencies. Slight antinociceptic properties were observed with three of the four compounds. The naloxone derivatives 3a and 3b appear to be attractive candidates for investigation as long-acting narcotic antagonists in view of their fourfold greater duration of action relative to the other antagonists (1, 2, 4a, and 4b).

Amination↗
PubMed1977

Myocardial infarct imaging agents. III. Synthesis and evaluation of [203Hg] hydroxymercuriphthaleins.

Four Hg-203-mercurated phthaleins were prepared, purified, and compared with [203Hg] mercuric nitrate, [3H] phenolphthalein [203Hg] hydroxymercurifluorescein and Tc-99m-pyrophosphate in a rat model of myocardial necrosis to determine their specificities for damaged myocardium. The ratios of damaged myocardium to normal myocardium, and to blood, for the [203Hg] hydroxymercuriphthaleins (20.7-34.1 and 12.1-20.1, respectively) were somewhat lower than those reported previously for [203Hg] hydroxymercurifluorescein, but were higher than those found with [203Hg] mercuric nitrate, [3H] phenolphthalein, and Tc-99m pyrophosphate. Both the hydroxymercuri- functional group and the phthalein moiety are required for selectivity. The removal of the oxygen bridge present in fluorescein, and the replacement of carboxylic acid by sulfonic acid, had no significant effects on the sequestration process in damaged tissue.

Animals↗
PubMed1977

Radiopharmaceuticals for acutely damaged myocardium. II: Synthesis and evaluation of [203Hg] hydroxymercurifluoresceins.

Six [203Hg] hydroxymercurifluoresceins were prepared by two methods and compared with [3H] fluorescein, [131I] rose bengal, and [203Hg] mercuric nitrate, in a rat model for myocardial necrosis, to determine their specificities for damaged myocardium (DM). The nonhalogenated [203Hg] hydroxymercurifluorescein had the highest ratios of the series for DM/normal heart (51.5+/-13.5) and DM/blood (22.1+/-8.1). Halide substituents at the 2' or 4' positions of the fluorescein moiety decreased the tissue selectivity, and bis-hydroxymercuration had no significant effect. The six tracers studied had greater absolute uptake and better target-to-nontarget ratios than [3H] fluorescein, [131I] rose bengal, or [203Hg] mercuric nitrate, indicating a cooperative effect between the fluorescein and hydroxymercuri-moieties in the overall sequestration process in damaged tissues.

Animals↗
PubMed1976

Picogram analysis of free triiodothyronine and free thyroxine hormones in serum by equilibrium dialysis and electron capture gas chromatography.

A methodology involving equilibrium dialysis and gas chromatography has been developed to measure concurrently the concentration of the dialyzable (i.e., free) fractions of thyroxine and 3,5,3'-triiodothyronine in serum. The electron capture response of the N,0-diheptafluorobutyryl methyl ester derivatives of these hormones allows their detection and quantitation in the picogram range (detection limit approx. 0.2pg). Purification of the dialysate is achieved using a cation-exchange column which is pretreated with diiodothyronine. Adsorption problems on the glassware are eliminated by silanization. The methodology also resolves 3,3',5'-triiodothyronine (reverse T3).

Adsorption↗
PubMedDate not supplied

Novel biotinylated phenylarsonous acids as bifunctional reagents for spatially close thiols: studies on reduced antibodies and the agonist binding site of reduced Torpedo nicotinic receptors.

We synthesized three novel organoarsenicals as prototype bifunctional reagents for spatially close thiols, N-(4-arsenosophenyl) hexahydro-2-oxo-(3aS,4S,6aR)-1H-thieno[3, 4-d]imidazole-4-pentamide (1), 2-[4-[(4-arsenosophenyl)amino]-1, 4-dioxobutyl] hydrazide, (3aS,4S,6aR)-hexahydro-2-oxo- 1H-thieno[3, 4-d] imidazole-4-pentanoic acid (2), and [4-[[12-[[5-[(3aS,4S, 6aR)-hexahydro-2-oxo-1H-thieno[3, 4-d]imidazol-4-yl]-1-oxopentyl]amino]-1-oxododecyl]amino]phe nyl]-arso nous acid (3) containing both biotin and arsenic with intervening varying length spacers extending from 2 to 15 A beyond biotin bound to streptavidin. Conceptually, the arsenical group can form a stable, covalent ring structure with appropriately spaced thiols and thereby anchor the reagent to a macromolecule, while biotin allows for the detection of the reagent-macromolecule complex via avidin binding. Because the alpha-subunits of all characterized nicotinic receptors contain an easily reducible disulfide bond between adjacent cysteine residues, the reduced alpha-subunit is an attractive site for labeling. Compounds 1-3 all simultaneously bound streptavidin and dithiols, and all three decreased the number of [125I]alpha-bungarotoxin-binding sites in reduced Torpedo nicotinic receptors (IC50s 10-300 nM). Moreover, arsenylation of the receptors prevented their reoxidation with dithio-bis(nitrobenzoic acid), was reversible with 2,3-dimercaptopropanesulfonic acid, and protected the receptor from irreversible alkylation by bromoacetylcholine. However, in no case did 1-3 allow simultaneous binding to reduced nicotinic receptors and to [125I]streptavidin, although 3 alone allowed simultaneous labeling of a spatially close dithiol located in reduced antibodies.

Animals↗