High red blood cell folate is associated with an increased risk of death among adults with diabetes, a 15-year follow-up of a national cohort.

BACKGROUND AND AIM: To describe the mortality and fatality of diabetes and assess their relationship with the level of red blood cell (RBC) folate. METHODS AND RESULT: We analyzed the data of 526 adults with diabetes who participated in the National Health and Nutrition Examination Survey (1991-1994) as the baseline examination, and were followed up through December 31, 2006. Estimates of the hazard ratios (HRs) of selected death causes for individuals with different levels of RBC folate were obtained from Cox proportional hazards regression. A total of 295 deaths were recorded by the end of a 15-year follow-up with a mortality rate of 58.48 per 1000 person year (py). Diabetes was listed as a contributing cause for 136 deaths, accounting for 46.1% of the total deaths with a fatality rate 26.96 per 1000 py. Mortality rate for all-cause in the group with upper quartile of RBC folate was almost twice as high as that among the group with lower quartile, 82.75 vs. 44.10 per 1000 py. After adjusting for covariates, including serum concentration of vitamin B12, cotinine, homocysteine and the history of cardio-cerebral vascular diseases assessed at the baseline, the HRs for dying from any causes were 1.00 (reference), 1.82 (95% CI = 1.25-2.66) and 2.10 (1.37-3.20) among diabetic adults with lower, intermediate, and upper quartiles of RBC folate. CONCLUSION: Diabetes was listed as a contributing cause for less than half of the deaths among adults with diabetes after 15+ years of follow-up; high RBC folate concentration was associated with an elevated risk of death among adults with diabetes.

Asymmetric Baeyer-Villiger oxidations of 4-mono- and 4,4-disubstituted cyclohexanones by whole cells of engineered Escherichia coli.

Whole cells of an Escherichia coli strain that overexpresses Acinetobacter sp. NCIB 9871 cyclohexanone monooxygenase have been used for the Baeyer-Villiger oxidations of a variety of 4-mono- and 4,4-disubstituted cyclohexanones. In cases where comparisons were possible, this new biocatalytic reagent provided lactones with chemical yields and optical purities that were comparable to those obtained from the purified enzyme or a strain of bakers' yeast that expresses the same enzyme. The efficient production of cyclohexanone monooxygenase in the E. coli expression system (ca. 30% of total soluble protein) allowed these oxidations to reach completion in approximately half the time required for the engineered bakers' yeast strain. Surprisingly, 4,4-disubstituted cyclohexanones were also accepted by the enzyme, and the enantioselectivities of these oxidations could be rationalized by considering the conformational energies of bound substrates along with the enzyme's intrinsic enantioselectivity. The enzyme expressed in E. coli cells also oxidized several 4-substituted cyclohexanones bearing polar substituents, often with high enantioselectivities. In the case of 4-iodocyclohexanone, the lactone was obtained in > 98% ee and its absolute configuration was assigned by X-ray crystallography. The crystal belongs to the monoclinic P2(1) space group with a = 5.7400(10), b = 6.1650(10), c = 11.377(2) A, b = 99.98(2) degrees, and Z = 2. Taken together, these results demonstrate the utility of an engineered bacterial strain in delivering useful chiral building blocks in an experimentally simple manner.