Dysfunction of the exocrine pancreas is observed in diabetes, but links between concurrent exocrine and endocrine pancreatic disease and contributing genetic factors are poorly characterized. We studied two families with diabetes and exocrine pancreatic dysfunction by genetic, physiological and in vitro functional studies. A genome-wide screen in Family 1 linked diabetes to chromosome 9q34 (maximal lod score 5.07). Using fecal elastase deficiency as a marker of exocrine pancreatic dysfunction refined the critical chromosomal region to 1.16 Mb (maximal lod score 11.6). Here, we identified a single-base deletion in the variable number of tandem repeats (VNTR)-containing exon 11 of the carboxyl ester lipase (CEL) gene, a major component of pancreatic juice and responsible for the duodenal hydrolysis of cholesterol esters. Screening subjects with maturity-onset diabetes of the young identified Family 2, with another single-base deletion in CEL and a similar phenotype with beta-cell failure and pancreatic exocrine disease. The in vitro catalytic activities of wild-type and mutant CEL protein were comparable. The mutant enzyme was, however, less stable and secreted at a lower rate. Furthermore, we found some evidence for an association between common insertions in the CEL VNTR and exocrine dysfunction in a group of 182 unrelated subjects with diabetes (odds ratio 4.2 (1.6, 11.5)). Our findings link diabetes to the disrupted function of a lipase in the pancreatic acinar cells.

Background:The quaternary ammonium compounds, choline and betaine, and dimethylglycine (DMG) reside along a metabolic pathway linked to the synthesis of neurotransmitters and membrane phospholipids and to homocysteine remethylation and, therefore, folate status. Lack of a convenient, high-throughput method for the determination of these compounds has prevented population-based studies of their possible associations with lifestyle, nutrition, and chronic diseases. Methods: Serum or plasma samples were deproteinized by mixing with three volumes of acetonitrile that contained d 9 -choline and d 9 -betaine as internal standards. We used a normal-phase silica column for the separation of choline (retention time, 2.8 min), betaine (1.3 min), DMG (1.15 min), and internal standards, which were detected as positive ions by tandem mass spectroscopy in the multiple-reaction monitoring mode, using the molecular transitions m/z 104360 (choline), m/z 113369 (d 9 -choline), m/z 118359 (betaine), m/z 127368 (d 9 -betaine), and m/z 104358 (DMG). Results: For all three metabolites, the assay was linear in the range 0.4 -400 mol/L, and the lower limit of the detection (signal-to-noise ratio ‫؍‬ 5) was <0.3 mol/L. The within-and between-day imprecision (CVs) was 2.1-7.2% and 3.5-8.8%, respectively. The analytical recovery was 87-105%. The fasting plasma concentrations (median, 25th-75th percentiles) were 8.0 (7.0 -9.3) mol/L for choline, 31.7 (27.0 -41.1) mol/L for betaine, and 1.66 (1.30 -2.02) mol/L for DMG in 60 healthy blood donors. In individuals who had eaten a light breakfast, plasma concentrations of all three metabolites

Betaine serves as a methyl donor in a reaction converting homocysteine to methionine, catalysed by the enzyme betaine-homocysteine methyltransferase. It has been used for years to lower the concentration of plasma total homocysteine (tHcy) in patients with homocystinuria, and has recently been shown to reduce fasting and in particular post-methionine load (PML) tHcy in healthy subjects. Betaine exists in plasma at concentrations of about 30 micromol/L; it varies 10-fold (from 9 to 90 micromol/L) between individuals, but the intra-individual variability is small. Major determinants are choline, dimethylglycine and folate in plasma, folic acid intake and gender. Recent studies have demonstrated that plasma betaine is a stronger determinant of PML tHcy than are vitamin B6 and folate. The betaine-PML tHcy relationship is attenuated after supplementation with B-vitamins, and is most pronounced in subjects with low folate. Betaine shows a weaker association with fasting tHcy (than with PML tHcy), and also this association is most pronounced in subjects with low folate. In pregnancy, plasma betaine declines until gestational week 20, and thereafter remains constant. From gestational week 20 onwards, fasting tHcy shows a strong inverse association with plasma betaine, and betaine becomes a stronger predictor than folate of fasting tHcy. To conclude, betaine status is a component of an individual's biochemical make-up with ramifications to one-carbon metabolism. Betaine status should be investigated in pathologies related to altered metabolism of homocysteine and folate, including cardiovascular disease, cancer and neural tube defects.

Objective: To investigate the effect of different antithyroid drug (ATD) regimens on relapse rates of Graves' disease, and to look for predictors of relapse. Design and Methods: In a prospective two-way factorial randomized clinical trial, 218 patients with Graves' disease were assigned to ATD combined with L-thyroxine (L-T 4 ) or ATD alone for 12 months. After discontinuation of antithyroid therapy, each group was stratified to either 12 months further treatment with L-T 4 or no treatment. Clinical and biochemical assessments were carried out before treatment, after 3 and 6 weeks, and every third month for 12 months. If the patients lacked symptoms of relapse, laboratory tests were performed every third month for the second year, and thereafter annually. Results: The proportion of all patients with relapse was 47.7% 2 years after withdrawal of ATD. There was no difference in relapse rates between the treatment groups (P ¼ 0:217; log-rank test). Smokers had a higher relapse rate than non-smokers (58.4% vs 38.8%, P ¼ 0:009). Patients who were thyrotropin-receptor antibody (TRAb) positive after 12 months of antithyroid therapy had a higher relapse rate than those who were negative (72.5% vs 36.8%, P , 0:0001). Similarly, relapse was more frequent (55.5%) in patients having large goiter compared with subjects with small goiter (36.3%, P ¼ 0:0007). Conclusions: Relapse rates of Graves' disease were independent of ATD regimen whether followed by L-T 4 therapy or not. Smoking, large goiter and presence of TRAb at the end of ATD therapy were strong predictors of relapse.