We analyzed early and late results of surgical treatment of 100 consecutive children with Down's syndrome (DS) and congenital heart defect (CHD) who were operated on between 1990 and 1997. Fifty had common atrioventricular canal (CAVC), 24 ventricular septal defect, 8 the ostium primum atrial septal defect, 8 tetralogy of Fallot (TOF), 3 patent ductus arteriosus, 3 the ostium secundum atrial septal defect, and 4 CAVC coexisting with TOF. In 93 patients total correction was performed. The total death rate was 6%. Death in the CAVC group was 8%, but it decreased to 2.7% during the past 3 years. The children who were followed up (from 7 months to 6 years; mean, 39 months) are in NYHA class I or II. There were no reoperations. The postoperative course was complicated by pulmonary infections in 38% of patients, which converted to generalized infection in 10% and was the cause of death in 8% of patients. These results indicate that CHD in DS children can be repaired with a low death rate and low incidence of severe mitral atrioventricular valve regurgitation in the CAVC group. A high incidence of severe infections can influence the final results. Repair of CHD in infancy helps to eliminate problems connected with congestive heart failure and pulmonary hypertension.

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Fractions of complex glycosphingolipids were prepared from adult, cord, and i phenotype erythrocytes by the method elaborated for the isolation of poly(glycosy1)ceramides. In contrast to poly(glycosy1)ceramides which comprise on the average 30 glycosyl units and about 5 branching points, i.e. 3,6-di-O-substituted galactopyranosyl residues, per mole of glucose, complex glycosphingolipids from cord and i erythrocytes comprise 6 and 15 glycosyl units respectively and only 0.7 branching points. The latter substances exhibited also a high i activity which was not detected in poly(glycosy1)ceramides.Erythrocyte membranes were labeled with radioactive N-acetylgalactosamine (GalNAc) from UDP-GalNAc using a purified A-blood-group gene-specified transferase of GalNAc. It was found that electrophoretic mobilities in dodecylsulfate-gel electrophoresis of all glycoconjugates which accepted GalNAc were increased in i as compared to I membranes. We conclude that the absence of highly branched glycosphingolipids in cord and i erythrocytes as well as the reduction of apparent molecular weights of the glycoconjugates, which are substrates for A-gene-specified transferase of GalNAc, result from a single cause, that is an inadequacy of the biosynthetic process which is responsible for the formation of GlcNAcl + 6Gal structures.

Evidence is presented that temperature-sensitive Saccharomyces cerevisiae mutants, impaired in dolichol kinase (Sec59p) or dolichyl phosphate mannose synthase (Dpm1p) activity have an aberrant cell wall composition and ultrastructure. The mutants were oversensitive to Calcofluor white, an agent interacting with the cell wall chitin. In accordance with this, chemical analysis of the cell wall alkali-insoluble fraction indicated an increased amount of chitin and changes in the quantity of β1,6-and β1,3-glucan in sec59-1 and dpm1-6 mutants. In order to unravel the link between the formation of dolichyl phosphate and dolichyl phosphate mannose and the cell wall assembly, we screened a yeast genomic library for a multicopy suppressors of the thermosensitive phenotype. The RER2 and SRT1 genes, encoding cis-prenyltransferases, were isolated. In addition, the ROT1 gene, encoding protein involved in β1,6-glucan synthesis (Machi et al., 2004) and protein folding (Takeuchi et al., 2006) acted as a multicopy suppressor of the temperature-sensitive phenotype of the sec59-1 mutant. The cell wall of the mutants and of mutants bearing the multicopy suppressors was analysed for carbohydrate and mannoprotein content. We also examined the glycosylation status of the plasma membrane protein Gas1p, a β1,3-glucan elongase, and the degree of phosphorylation of the Mpk1/Slt2 protein, involved in the cell wall integrity pathway.

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