Glycosphingolipids of Membrane Fractions from Normal and Transplanted Canine Kidney

Reflections on my career in analytical chemistry and biochemistry

My career has been focused in two major areas, analytical chemistry and biochemistry of complex lipids and glycoconjugates. Included here are the pioneering work on the gas chromatography of long-chain sphingolipid bases, carbohydrates, steroids and urinary organic acids. Mass spectrometry was utilized extensively in structural studies of sphingolipids, fatty acids, carbohydrates, steroids, urinary organic acids, polyisoprenoid alcohols, and juvenile hormone. Computer systems were developed for the acquisition and analysis of mass spectra, and were used for development of automated metabolic profiling of complex mixtures of metabolites. Fabry's disease was discovered to be a glycosphingolipidosis. Enzymes of lysosomal metabolism of glycosphingolipids were purified, characterized, and used in one of the first demonstrations of the feasibility of enzyme replacement therapy in a lysosomal storage disorder (Fabry's disease). Extracellular sialidases were studied to evaluate the hypothesis that they might be involved in the regulation of membrane growth factor receptors. The enzyme for hematoside synthesis was purified and characterized.

SV40 tumor rejection induced by vesicular stomatitis virus bearing SV40 tumor-specific transplantation antigen (SV40-TSTA). II. Association of SV40-TSTA activity with liposomes containing VSV glycolipids

Highly purified vesicular stomatitis virus (VSV) was obtained from VSV-infected SV40-transformed and from "normal" hamster cell lines. A glycolipid extract was prepared from these VSV preparations according to the Folch partition procedure. These glycolipids were rendered immunogenic to the Syrian hamsters when incorporated within liposomal membranes composed of lecithin/sphingomyelin/cholesterol (1/1/2 by weight). When the glycolipids were extracted from VSV grown on cell lines (TSV5-cl2 and EHSVi-cl1) which contained the SV40 tumor-specific transplantation antigen (SV40-TSTA), it was possible either to induce a tumor rejection or at least to slow the growth of the tumor in Syrian hamsters challenged with TSV5-cl2 cells. No protection was obtained in animals treated with liposomes containing glycolipids extracted from purified VSV grown on SV40-TSTA-negative cells (EHB). The SV40-TSTA could be a glycolipid of the transformed cell membrane which is incorporated within the VSV envelope.

Water-soluble glycosphingolipids of dog gastric mucosa. Characterization of a branched ceramide heptasaccharide

Two glycosphingolipids, the carbohydrate portion of which consisted of galactose, glucose and N-acetylgalactosamine, have been isolated from the aqueous phase of buffered tetrahydrofuran extract of dog gastric mucosa. The structures of these glycolipids were identified by partial acid hydrolysis, sequential degradation with specific glycosidases and methylation analysis. The structure of glycolipid I (GalNAcalpha1 leads to 3GalNAcbeta1 leads to 3Galalpha1 leads to 4Galbeta1 leads to 4Glc leads to ceramide) was found to be identical to that of Forssman hapten. The branched structure of glycolipid II, as determined by the combination of enzymatic degradation and comparison of the permethylation products of the enzyme-degraded compounds, is proposed to be: See Source.

[Concentration of plasma glycosphingolipids in acute hepatitis (author's transl)]

There are mainly four neutral glycosphingolipids in human blood plasma: Monohexosyl, dihexosyl, trihexosyl and tetrahexosyl ceramide. In patients with viral hepatitis (n=21) during the acute phase all four fractions of plasma glycosphingolipids were elevated compared to healthy subjects (n=23). With the exception of trihexosyl ceramide all fractions demonstrated statistically striking elevations in the acute phase of viral hepatitis. Simultaneously in the acute phase of hepatitis triglycerides and cholesterol in serum were significantly increased. It is concluded the elevation of glycosphingolipid levels in plasma is a metabolic consequence of hyperlipoproteinemia. Furthermore it is supposed that a part of plasma glycosphingolipids is synthezised de novo by the liver like VLDL.

[Plasma glycosphingolipids: concentration and distribution in different types of hyperlipoproteinemia (author's transl)]

There are mainly four neutral glycosphingolipids in human blood plasma: Monohexosyl, dihexosyl, trihexosyl and tetrahexosyl ceramide. In patients with hyperlipoproteinemia (hlp) type IIa (n = 10), type IIb (n = 9), type IV (n = 24), and type V (n = 11) all four fractions of plasma glycosphingolipids were elevated compared to healthy subjects (n = 23). In all types of hlp monohexosyl ceramides were significantly augmented (p less than 1%). Trihexosyl and tetrahexosyl ceramides demonstrated only in single types statistically striking elevation. There was no significant elevation of dihexosyl ceramides. In the VLDL the distribution of all glycosphingolipids showed increase in hlp type IV and type IIb. In the LDL the distribution showed increase in type IIa. There exists a strong correlation with the elevated prae-beta-lipoproteins respectively beta-lipoproteins. It is concluded that elevation of glycosphingolipid levels in plasma is a metabolic consequence of hyperlipoproteinemia. It is considered that a part of plasma glycosphingolipids is de novo synthesized by the liver like VLDL. The role of plasma glycosphingolipids in atherogenesis is discussed.