Biomedical subjects

E Shefter

Publications and source records attributed to E Shefter.

At least 37 records · Page 2Linked to original sources

PubMed1982

Urinary calcium oxalate monohydrate crystals in ethylene glycol poisoning.

Four patients admitted for ethylene glycol intoxication had massive crystalluria, predominantly of needle-shaped calcium oxalate monohydrate--sometimes referred to as the 'hemp seed' habit. A few 'envelope' type crystals of calcium oxalate dihydrate were observed in one urine sample. Although not a pathognomonic sign, the presence of a large number of calcium oxalate monohydrate crystals (Whewellite) supports the diagnosis of ethylene glycol poisoning in patients having a metabolic acidosis of unknown aetiology. We conclude that the monohydrate form rather than the dihydrate form is the predominant type of calcium oxalate crystal formed in ethylene glycol poisoning.

Adult↗

PubMed1980

Crystal structures of calcium channel antagonists: 2,6-dimethyl-3,5-dicarbomethoxy-4-[2-nitro-, 3-cyano-, 4-(dimethylamino)-, and 2,3,4,5,6-pentafluorophenyl]-1,4-dihydropyridine.

The crystal structures of 2,6-dimethyl-3,5-dicarbomethoxy-4-(2-nitrophenyl)-1,4-dihydropyridine (Nifedipine) and the 3-cyano-, 4-(dimethylamino)- and 2,3,4,5,6-pentafluorophenyl derivatives were determined. The 1,4-dihydropyridine ring in all four compounds has a boat-type conformation with varying degrees of puckering at the C4 position. Increasing distortion from planarity at this position shows a limited correlation with decreasing biological activity, determined as the ability to inhibit the Ca2+-dependent muscarinic-induced mechanical responses of guinea pig ileal longitudinal smooth muscle.

Animals↗

PubMed1976

Stereochemical studies on medicinal agents. 19. X-ray crystal structures of two (+/-)-allylprodine diastereomers. The role of the allyl group in conferring high stereoselectivity and potency at analgetic receptors.

X-Ray crystallographic studies have been performed on the two diasteromeric racemates of 3-allyl-1-methyl-4-propionoxypiperidine hydrochloride (allylprodine hydrochloride) in an effort to determine the role of conformation in their interaction with analgetic receptors sites. The chiral orientation of the phenyl group in the highly potent isomer, (+)-1, is qualitatively in conformity with the stereo structure-activity relationship found among other analgetic 4-phenylpiperdines. The fact that (+)-2, a relatively weak analgetic with no stereoselectivity, also possesses this feature indicates that this conformational arrangement per se does not ensure high potency. The data suggest that the very potency and stereoselectivity which the allylic double bond confers to (+)-1 are due primarily to the interaction of this bond with an accessory site on the receptor.

Allyl Compounds↗

PubMed1975

Analysis of N-glycosyl bond length in crystal structures of nucleosides and nucleotides.

A relationship was found between the N-glycosyl bond length in beta-nucleosides and nucleotides and the spatial relationship of this bond with respect to the lone-pair orbitals on the furanose ring oxygen. This relationship may be relevant to the geometry involved in the hydrolysis of the glycosidic bond.

Crystallization↗

PubMed1974