Production of Multiple Brain-Like Ganglioside Species Is Dispensable for Fas-Induced Apoptosis of Lymphoid Cells

Activation of an acid sphingomyelinase (aSMase) leading to a biosynthesis of GD3 disialoganglioside has been associated with Fas-induced apoptosis of lymphoid cells. The present study was undertaken to clarify the role of this enzyme in the generation of gangliosides during apoptosis triggered by Fas ligation. The issue was addressed by using aSMase-deficient and aSMase-corrected cell lines derived from Niemann-Pick disease (NPD) patients. Fas cross-linking elicited a rapid production of large amounts of complex a- and b-series species of gangliosides with a pattern and a chromatographic behavior as single bands reminiscent of brain gangliosides. The gangliosides were synthesized within the first ten minutes and completely disappeared within thirty minutes after stimulation. Noteworthy is the observation that GD3 was not the only ganglioside produced. The production of gangliosides and the onset of apoptotic hallmarks occurred similarly in both aSMase-deficient and aSMase-corrected NPD lymphoid cells, indicating that aSMase activation is not accountable for ganglioside generation. Hampering ganglioside production by inhibiting the key enzyme glucosylceramide synthase did not abrogate the apoptotic process. In addition, GM3 synthase-deficient lymphoid cells underwent Fas-induced apoptosis, suggesting that gangliosides are unlikely to play an indispensable role in transducing Fas-induced apoptosis of lymphoid cells

On the structure of cytolipin R, a ceramide tetrahexoside hapten from rat lymphosarcoma

Cytolipin R, a ceramide tetrahexoside isolated from rat lymphosarcoma, was studied by sequential hydrolysis with specific glycosidases which revealed the anomeric configurations of the glycosidic bonds. Sugar linkages were established by combined gas liquid chromatography and mass spectrometry of the partially methylated alditol acetates prepared after permethylation and hydrolysis of the intact lipid. Results indicated the structure of cytolipin R to be N acetylgalactosaminyl (β1→3) galactosyl (α1→3) galactosyl (β1→4) glucosyl ceramide. Cytolipin K (globoside I) differs in having a galactosyl (α1→4) galactosyl internal linkage, and this difference must account for the immunological differences between cytolipin K and cytolipin R

Design and Modelling of 3D Printed Capacitive Displacement Sensor

The aim of the work is the realization and modelling of a simple capacitive displacement sensor with the use of 3D printing technology and polylactic acid (PLA) material. The sensor consists of three 3D printed PLA parts: Two electrodes with cavities and a spacer. The silver paste is not printed but micromolded by filling it into the cavities of printed PLA electrodes via a syringe. The capacitance of the fabricated sensor versus applied displacement is measured and compared with calculated capacitance of simple sensor model. A simple model of a sensor capacitor is not capable of describing the behavior of this type of sensor. Therefore, more complex model of sensor capacitor is given better fit to measured results. Additionally, the hysteresis of the fabricated sensor is tested

Investigation of Dielectric Properties of Printed Material for Capacitor Application

This paper investigates the dielectric characteristics of the material used to make capacitor in fused filament fabrication technology. The characteristics of the capacitor made of PLA (Polylactic Acid) as dielectric are examined. Using a 3D printer, dielectric samples are created in the form of a disk 8.6 mm in diameter. Preliminary samples revealed that the surfaces of the printed samples are rough, after which the mechanical treatment of the samples is applied. The thicknesses of the samples belbre and after polishing are 1 mm and 0.7 mm, respectively. Epoxy electrodes are applied to the dielectric disks on both surfaces to produce the parallel plate capacitors. The capacitance of the fabricated capacitors is measured in the low frequency range, from 0.1 Hz to 200 kHz. The dissipation characteristics of the capacitor are examined, and a measured average value of tangent loss is 0.007. The printed dielectric samples without the electrodes are used to investigate their ability to withstand voltages up to 6 kV. The measurement results confirmed that the used PLA material is suitable for the fabrication of he capacitor with good characteristics