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Biomedical subjects

S G Huang

Publications and source records attributed to S G Huang.

23 records · Page 2Linked to original sources

A 500 MHz 1H NMR spectroscopic study of Met5-enkephalinamide in aqueous solution: ethanol induced conformational changes.

An analysis of spin coupling constants, less than 3J greater than C alpha H-NH, from a high resolution 500 MHz 1H NMR study of [Met5]-enkephalinamide in aqueous solution, suggested that beta-sheet structure is the likely conformer. The effect of ethanol on the conformation of [Met5]-enkephalinamide in aqueous solution was investigated. From the upfield drift of observed chemical shifts and changes in coupling constants, especially of the amide NH resonances, it is concluded that ethanol disrupts the conformation possibly by influencing the hydrogen bonding. The above observation is consistent with a recent study of the ethanol induced conformational changes occurring in [Met5]enkephalinamide [Rapaka, R.S. et al. (1986) Life Sciences 39, 837-842].

Enkephalin, Methionine↗

Conformational analysis of cyclized dipeptide models for specific types of beta-bends by two-dimensional nuclear Overhauser spectroscopy.

The solution conformations in DMSO-d6 of the two cyclized dipeptides, cyclo(L-alanyl-L-alanyl-epsilon-aminocaproyl) and cyclo(L-alanyl-D-alanyl-epsilon-aminocaproyl), have been analyzed by means of the two-dimensional nuclear Overhauser effect (2D-NOE). The preferred conformations for the two compounds have been deduced by comparing proton-proton distances, derived from the 2D-NOE data and relaxation-time measurements, with the corresponding distances in several possible computed low-energy conformations. The predominant conformations are a type III bend and a type II bend, respectively, for the two compounds. These conclusions agree with those deduced earlier on the basis of infrared and Raman spectra and circular dichroism measurements.

Magnetic Resonance Spectroscopy↗

Serum analyte pattern characteristic of fulminant hepatic failure.

Fulminant hepatic failure (FHF) is a poorly understood condition in which total liver failure occurs and is thought to be caused by a variety of conditions including Reye's syndrome, hepatitis, drug overdoses, and vascular insufficiency. While this condition is an uncommon one, it carries with it a high fatality rate and must therefore be diagnosed as rapidly as possible. Six patients have been observed over a two-year period with biopsy and/or autopsy-confirmed FHF: one with acute hepatitis B-delta; three with histories of alcoholism, two of them with cirrhosis; one with acute tylenol overdose; and one with hepatic vascular insufficiency. All of these patients, except one, exhibited a rapid, fatal downhill course after onset of symptoms. In all of these patients, a consistent elevation was observed in serum levels of aspartate aminotransferase (AST) or serum glutamate oxaloacetate transaminase (SGOT) and alanine aminotransferase (ALT) or serum glutamate pyruvate transaminase (SGPT) such that the ratio of AST to ALT was significantly greater than 1 and in serum levels of ammonia. Other liver function tests were found to be abnormal but not in so consistent a pattern, although total protein and albumin were found to be significantly decreased in all of these patients. The stereotypical elevation of the transaminases with high AST-to-ALT ratios and the rise in ammonia appear to characterize this life-threatening illness most reliably.

Acetaminophen↗