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Biomedical subjects

N Schwartz

Publications and source records attributed to N Schwartz.

At least 19 recordsLinked to original sources
PubMed1991

Dibasic amines as competitive ions improve the resolution between polyanionic nucleotides.

Aliphatic diamines when used as single ion pairing reagents were capable of resolving 3'-,5'- and 2'-,5'- nucleotidyl diphosphates from one another while conventional ion pairing reagents did not separate these positional isomers. The use of 1,2-diamines resulted in the greatest resolution while increasing spacing between the amino groups progressively reduced the resolution while increasing the retention volume. A competitive ion pairing system was also developed using triethylamine as an additional ion pairing reagent. Using this system ethylenediamine, 1,2- and 1,3-diaminopropane were nearly equivalent in their ability to resolve adenosine 3'-phosphate 5'-phosphate, from adenosine 2'-phosphate 5'-phosphate, and adenosine 3'-phosphate 5'-beta-methylenephosphosulfate (3'-mePAPS) from adenosine 2'-phosphate 5'-beta-methylenephosphosulfate (2'-mePAPS), respectively. The ability to easily resolve these positional isomers allows the use of a more simplified synthetic procedure that does not involve the use selective protecting groups to specifically phosphorylate the 2' or 3' hydroxyl group. We have used this procedure on a semipreparative scale to obtain small quantities of both mePAPS and 2'-mePAPS for use in enzymatic studies.

Adenine Nucleotides↗
PubMed1989

Malignant hyperthermia in a child with sleep apnea.

Malignant hyperthermia is a syndrome characterized by a hypermetabolic state of skeletal muscle (1, 2). It is transmitted by genetic inheritance. The syndrome has frequently been associated with certain neuromuscular and other disorders (1, 3). A case of the syndrome occurring in a child with sleep apnea syndrome, an association not previously reported, is discussed here.

Child↗
PubMed1978

2-Pyrrolidinylideneureas, a new class of central nervous system agents.

A series of N-aryl-N'-(1-methyl-2-pyrrolidinylidene)ureas was prepared and screened for pharmacological activity. Congeners possessing either phenyl or phenyl substituted with 4-nitro, 3-bromo, 3-chloro, 3-fluoro, and 3-methyl groups were found to demonstrate anxiolytic activity. 2,6-Disubstitution of the phenyl ring with methyl, chloro, and bromo imparted potent muscle-relaxant properties which appear to be centrally mediated. A significant separation of the anxiolytic and muscle-relaxant properties from other CNS activities, e.g., anticonvulsant, sedative, and hypnotic, was achieved.

Animals↗
PubMed1978

Effect of uremia on tumor growth in mice.

Outbred Swiss mice of the Hebrew University strain were subtotally nephrectomized. The experimental and control animals were both divided into two subgroups, with one group kept on a regular animal house diet and one on a low-protein diet. All the animals were injected with Ehrlich's ascites tumor cells s.c. into the neck region. Two weeks later, the animals were killed and the tumor was excised and weighed to the nearest milligram. Tumor size in the uremic animals--the nephrectomized animals kept on a regular diet--was significantly smaller than in all other groups, which had blood urea nitrogen levels well within the normal range. It is suggested that urea may be a factor responsible for inhibiting tumor growth.

Animals↗