The thiobarbituric acid reacting material produced during enzymatic microsomal lipid peroxidation has been identified as malonaldehyde. The malonaldehyde was condensed with urea to form 2‐hydroxy‐pyrimidine, which was identified by its ultraviolet spectrum, chromato‐graphic properties, and mass spectrum. Incubations with phosphatidyl choline labelled with tritiated arachidonate yielded 2‐hydroxy‐pyrimidine with a specific activity nearly equal to that of the phospholipid arachidonate. Incubations with tritiated arachidonic acid yielded 2‐hydroxy‐pyrimidine with a specific activity nearly 2 orders of magnitude less than that of free arachidonic acid. Therefore, phospholipid arachidonate has been established as the major source of the malonaldehyde produced during microsomal lipid peroxidation.

This review summarises present knowledge of the chemistry, immunology, genetics and clinical significance of antibodies in the Lewis and secretor histo-blood group systems. Although red cell serology has laid the foundations for these systems, more recent advances have been made by studying Lewis and related glycoconjugates with monoclonal antibodies, determining structures by mass spectrometry and NMR spectroscopy, identifying enzymes and their specificities, and identifying the genes by molecular biology. The expression of Lewis system antigens is dependent on Lewis and secretor loci. Fucosyltransferases coded by genes at these loci compete and interact with each other and with other transferases to determine an individual's Lewis and secretor phenotype. Exocrine epithelial cells, mostly of endodermal origin, synthesise the Lewis antigens which, as plasma glycolipids, are secondarily acquired by cells of the peripheral circulation. Phenotyping red cells is often regarded as a simple way of determining the Lewis and sometimes the secretor status of an individual; however, the red cell phenotype is influenced by many factors and may not necessarily reflect someone's Lewis and secretor genotypes. Two main red cell Lewis groups are usually found, Lewis negative and Lewis positive. In Lewis-negative individuals, the secretor genotype does not affect the Lewis phenotype, but in Lewis-positive individuals, the non-secretor genotype generates the Le(a+b-) phenotype, the secretor genotype causes the Le(a-b+) phenotype, and the partial secretor genotype gives rise to the Le(a+b+) phenotype.

Objective: Definition of the molecular basis of the Reunion and the Bombay red cell and salivary H-deficient phenotypes. Methods: Sequence and expression of FUT1 and FUT2 genes from H-deficient individuals. Family segregation analysis of the mutations responsible for the fucosyltransferase defects of H, secretor and Lewis systems. Results: The Indian red cell H null Bombay phenotype depends on a new mutation of the FUT1 gene. T725 → G changing Leu242 → Arg. Their salivary nonsecretor phenotype is secondary to a complete deletion of the FUT2 gene. The red cell H weak Reunion phenotype depends on another new mutation of FUT1, C349 → T which induces a change of His117 → Tyr. Their salivary nonsecretor phenotype is due to the known Caucasian inactivating mutation G428 → A. Conclusion: Single prevalent FUT1 and FUT2 point mutations and a deletion are responsible for the Indian Bombay H null and the Reunion H weak phenotypes found on Reunion island. This is in contrast with other H-deficient phenotypes where sporadic nonprevalent inactivating mutations are the rule.

Aims/hypothesis The aim of this study was to investigate the safety and efficacy of alum formulated glutamic acid decarboxylase GAD 65 (GAD-alum) treatment of children and adolescents with type 1 diabetes after 4 years of follow-up. Methods Seventy children and adolescents aged 10-18 years with recent onset type 1 diabetes participated in a phase II, double-blind, randomised placebo-controlled clinical trial. Patients identified as possible participants attended one of eight clinics in Sweden to receive information about the study and for an eligibility check, including a medical history. Participants were randomised to one of the two treatment groups and received either a subcutaneous injection of 20 μg of GAD-alum or placebo at baseline and 1 month later. The study was blinded to participants and investigators until month 30. The study was unblinded at 15 months to the sponsor and statistician in order to evaluate the data. At follow-up after 30 months there was a significant preservation of residual insulin secretion, as measured by C-peptide, in the group receiving GAD-alum compared with placebo. This was particularly evident in patients with <6 months disease duration at baseline. There were no treatment-related serious adverse events. We have now followed these patients for 4 years. Overall, 59 patients, 29 who had been treated with GAD-alum and 30 who had received placebo, gave their informed consent. Results One patient in each treatment group experienced an episode of keto-acidosis between months 30 and 48. There were no treatment-related adverse events. The primary efficacy endpoint was the change in fasting C-peptide concentration from baseline to 15 months after the prime injection for all participants per protocol set. In the GADalum group fasting C-peptide was 0.332±0.032 nmol/l at day 1 and 0.215 ± 0.031 nmol/l at month 15. The corresponding figures for the placebo group were 0.354± 0.039 and 0.184±0.033 nmol/l, respectively. The decline in fasting C-peptide levels between day 1 and month 1, was smaller in the GAD-alum group than the placebo group. The difference between the treatment groups was not statistically significant. In those patients who were treated within 6 months of diabetes diagnosis, fasting C-peptide had decreased significantly less in the GADalum group than in the placebo-treated group after 4 years.

The SewA385T mutation of the FUT2 gene was found to correlate with both the erthrocyte Le(a + b+) and/or salivary ABH partial-secretor phenotypes of Polynesians. Constructs with FUT1 and FUT2 wild type genes, and the FUT2 SewA385T, seG428A and seC571T mutated alleles, were cloned into pcDNAI, and expressed in COS-7 cells. COS-7 cells transfected with the SewA385T allele had weak, but detectable, alpha(1,2)fucosyltransferase activity, with an acceptor substrate pattern similar to the wild type FUT2 gene. Comparative kinetic studies from cell extracts with mutated SewA385T and wild type FUT2 alleles gave similar Km values, but less enzyme activity was present in cells transfected with SewA385T (Vmax 230 pmol h-1 mg-1), as compared to those transfected with FUT2 (Vmax 1030 pmol h-1 mg-1), suggesting that the mutated enzyme is more unstable. These results confirm that the molecular basis for the erythrocyte Le(a + b+), and the associated ABH salivary partial-secretor phenotype, is an amino acid change of Ile129-->Phe in the secretor alpha(1,2)fucosyltransferase.