Chiyuki Suzuki

Glycolipids isolated from porcine intestine

Abstract Preparative silicic acid-Hyflo Supercel column chromatography of crude lipid extracts of porcine intestine gave two glycolipid fractions. The larger fraction was separated into hematosides, porcine intestinal glycolipids I & II (PIGL-I & PIGL-II) and sphingomyelin by rechromatography on a silicic acid-Hyflo Supercel column and a DEAE-cellulose column. Final purification of these glycolipids was achieved by thinlayer chromatography. The amounts of PIGL-I & PIGL-II were found to be more than half of the total sphingoglycolipids containing hexosamine or sialic acid, although other glycolipids of this type, hematosides and globoside I, were also isolated in appreciable amounts. From the smaller fraction, cerebrosides (CMH), ceramide dihexosides (CDH), ceramide trihexoside (CTH), cerebroside sulfate (CMHS) and globoside I were isolated by means of rechromatography with silicic acid-Hyflo Supercel, and subsequently by column chromatography with DEAE-cellulose or Florisil. CDH, CTH and globoside I were finally separated by thin-layer chromatography. These ceramide hexosides also were found to be major glycolipids in porcine intestine. CMHS was however obtained in a small amount. These glycolipids were characterized further by qualitative and quantitative analyses as follows: ceramide glucoside & ceramide galactoside (CMH); 3 ceramide galactoside sulfate (CMHS); ceramide lactoside & ceramide digalactoside (CDH); digalactosylglucosyl-ceramide (CTH); N -acetylgalactosaminyldigalactosylglucosyl-ceramide (globosidel); N -acetyl- and N -glycolyl-neuraminylgalactosylglucosylce-ramides (hematosides); glycolipid containing glucose, galactose, N -acetylhexosamine (glucosamine: galactosamine = 1:1), fucose, and ceramide in the molar ratio of approximately 1:2:1:1:1 (PIGL-I); glycolipid consisting of glucose, galactose, N -acetylglu-cosamine, fucose and ceramide in the molar ratio of about 1:2:2:1:1 (PIGL-II). The glycolipids showed large variation in fatty acid composition. Fatty acid compositions of PIGL-I and PIGL-II resembled each other, showing a similarity to that of CDH, but differed remarkably from those of globoside I and hematosides. On the basis of column and thin-layer chromatography and of analytical data, PIGL-I and PIGL-II were shown to be novel glycolipids. From the present observations and comparison with previous reports, the glycolipid composition of porcine intestine is species and organ specific.

T cell-mediated inhibition of erythropoiesis in aplastic anaemia: the possible role of IFN-γ and TNF-α

Summary. The inhibitory activity of T cells on autologous erythroid colony‐forming units (CFU‐E) (T cell inhibitory activity) in patients with aplastic anaemia (AA) was investigated. In 11 (32·4%) out of 34 AA cases, T cell inhibition on autologous CFU‐E growth was greater than that in normal individuals. In order to evaluate the mechanism of this inhibitory activity, T cell surface markers, interferon (IFN) production in peripheral blood mononuclear cell (PBMNC) liquid culture, and cytokine levels such as IFN and tumour necrosis factor‐α (TNF‐α) in CFU‐E clot cocultured with T cells, were measured in a portion of the patients. In five patients investigated for IFN production in PBMNC liquid culture, all produced statistically more IFN activity than normal individuals under phytohaemagglutinin (PHA‐P) stimulation (P<0·01) with no relation to T cell inhibitory activity. In only one patient whose T cells displayed increased CD8 and HLA‐DR antigen (CD8+HLA‐DR+) and inhibitory activity, a significant amount of IFN‐γ was observed in CFU‐E clot cocultured with T cells, and the addition of anti‐IFN‐γ antibody to the coculture resulted in recovered CFU‐E colony growth. These results suggest that IFN‐γ production by T cells may explain, at least in part, the pathogenesis of haematopoietic defects in AA. In other patients however, T cell inhibitory activity neither correlated to the T cell subpopulations (CD4+/CD8+, CD8+HLA‐DR+), IFN production in PBMNC liquid culture, nor to IFN and TNF‐α levels in CFU‐E clot culture. The roles played by cytokines other than IFN and TNF‐α on haematopoietic precursor cells require further evaluation in a larger sample of patients with AA.

A Recurrent Nonrandom Translocation (3;7)(q27;p12) Associated with Bcl-6 Gene Rearrangement in B-Cell Diffuse Large Cell Lymphoma

Two cases of B-cell diffuse large cell lymphoma associated with the t(3;7)(q27;p12) and BCL-6 rearrangement are described. Cytogenetic studies revealed [case 1] 47,XY,t(3;7)(q27;p12),+12 and [case 2] 45,X,-Y,t(3;7)(q27;p12),del(6)(q21q25),+16,-21. The translocation of each case had a non-random chromosomal change involving a 3q27 locus associated with BCL-6 gene rearrangement identified by Southern blot analysis. Both cases involved multiple lymph nodes and extranodal regions, such as stomach and peritoneal cavity in case 1, extranodal retroperitoneal space, subcutis, probable liver, and colon in case 2. Chemotherapy provided only short survival after onset: 17 and 16 months, respectively. Altered expression of adhesion molecules CD44, CD54 (case 1) and CD11a and CD18 (case 2) may help to explain the poor outcome of these patients.