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L Schneck

Publications and source records attributed to L Schneck.

13 recordsLinked to original sources
PubMed1991

SV-40 transformation: effect on GM2 ganglioside in cultured cell lines.

In previous work, we observed the presence of substantially elevated levels of GM2 after Simian Virus 40 (SV-40) transformation of human fetal brain cells. This elevated level of GM2 contrasted with the reports of many other investigators who had often observed decreased levels of GM2 and a simplification of ganglioside pattern in various non-neural rodent cell lines. In order to determine if the increase in GM2 in the transformed human brain cells would also be found in transformed rodent brain cells, we analyzed ganglioside changes after transformation in mouse brain cell lines and observed the increase in GM3 and low levels or lack of GM2 usually noted in rodent SV-40 transformed cell lines. In addition, we analyzed changes after SV-40 transformation in three human fibroblast lines and found that all three lines contained substantially elevated levels of GM2 after SV-40 transformation. As a result of this study, our earlier work on SV-40 transformed human brain cells, and occasional other reports of high levels of GM2 in human SV-40 transformed cell lines, elevated levels of GM2 may be considered a marker for SV-40 transformed human cells of both fibroblastic and neural origin.

Animals↗
PubMed1979

Cytology, growth characteristics and cellular alterations following SV40-induced transformation of human foetal brain cells derived from a Gm2 gangliosidosis and control.

Cell cultures were derived from the cerebra of a control and a Gm2 gangliosidosis (Tay-Sachs disease (TSD)) foetus. Both cell lines were identified as astrocytic, based on the ultrastructural demonstration of glial fibres. The control culture exhibited morphological differentiation when exposed to dibutyryl cAMP, a finding which was not observed with the TSD cells. The TSD culture demonstrated the pathobiological features of the disease, which included the absence of hexosaminidase A, increased concentration of Gm2 ganglioside and the detection of membranous cytoplasmic bodies by electron microscopy. Control and TSD cells were exposed to SV40 virus, resulting ultimately in the isolation of transformants which differed from the parental cell types in morphology, growth rate and greatly accelerated cell death. Both control and TSD cell lines have been in propagation for over 200 subcultures and the transformants were identified as astrocytic, based on the retention of characteristic glial fibres. The control culture demonstrated a chromosome range of 34--63, with a mean of 47. In contrast, the TSD transformants exhibited a range of 50--107 and a mean of 74. Transformed lines retained their parental hexosaminidase isoenzyme profiles; Hex A and B in control, and Hex B in TSD cells. Membraneous cytoplasmic bodies persisted in the TSD line. Neither line could be induced to differentiate after exposure to cAMP. Additionally, they had a population doubling time of under 85 h and failed to release infectious virus particles. Significant alterations in the total quantity and distribution profile of gangliosides were noted following viral transformation. A large increase in the percentage of Gm3 and a more modest increase in Gm2 were detected. In contrast, transformed lines were characterized by substantial reduction in the percentage of glucosamine-containing Gm2 and polysialoganglioside. Additionally, cultures exhibited a characteristic reduction in ganglioside content after transformation. The in vitro transformation of human brain cells has resulted in the derivation of permanent astrocytic lines which are, by virtue of their rapid growth rate and long-term survival, uniquely suited and adapted to the large scale in vitro production of substantial quantities of cells required for extensive biochemical study. Significantly, those characteristics which are unique to the Gm2 gangliosidosis storage disease have been retained in a permanent model CNS cell line.

Brain↗
PubMed1976

GM2 ganglioside in fetal Tay-Sachs disease brain cultures: a model system for the disease.

Cultured cells derived from Tay-Sachs disease (TSD) fetal cerebellum were shown to accumulate GM2 ganglioside when compared with control cultures. In contrast, fibroblasts derived from TSD fetal lung do not contain GM2. GM2 was identified by thin-layer chromatography (TLC) and confirmed by gas-liquid chromatography (GLC). Unlike fetal TSD brain, the cell cultures established from fetal TSD brain have high concentrations of globoside and GD3 and little or no asialo GM2(GA2). The GM2 and related glycosphingolipids in these cultured cells contain a high percentage of C24:0 and C24:1 fatty acids. In spite of these differences, this TSD cell strain is unique in that it accumulates GM2, and can therefore serve as a useful in vitro model for the study of TSD.

Cells, Cultured↗
PubMed1975

The gangliosidoses.

The gangliosidoses are hereditary diseases with a recessive mode of inheritance and are caused by a genetically induced enzymatic block, which results in the accumulation of gangliosides in various tissues of the body, mainly in the brain. Although Tay-Sachs disease, the most commonly occurring of the gangliosidoses, has been known for nearly 100 years, additional variants of ganglioside "storage" disorders have been discovered during the past 15 years. Considerable progress in the knowledge of these disorders has been made with the advent of electron microscopy and with the elaboration of new biochemical and enzyme-chemical techniques. At the present the gangliosidoses are not amenable to therapy. Therefore the foreseeable future the pragmatic approach involves identification of the high-risk pregnancy and antenatal diagnosis.

Axons↗