The long-term impact of dietary carbohydrate type, in particular sucrose, on insulin resistance and the development of diabetes and atherosclerosis is not established. Current guidelines for the healthy population advise restriction of sucrose intake. We investigated the effect of high-versus low-sucrose diet (25 vs. 10%, respectively, of total energy intake) in 13 healthy subjects aged 33 ؎ 3 years (mean ؎ SE), BMI 26.6 ؎ 0.9 kg/m 2 , in a randomized crossover design with sequential 6-week dietary interventions separated by a 4-week washout. Weight maintenance, eucaloric diets with identical macronutrient profiles and fiber content were designed. All food was weighed and distributed. Insulin action was assessed using a two-step euglycemic clamp; glycemic profiles were assessed by the continuous glucose monitoring system and vascular compliance by pulse-wave analysis. There was no change in weight across the study. Peripheral glucose uptake and suppression of endogenous glucose production were similar after each diet. Glycemic profiles and measures of vascular compliance did not change. A rise in total and LDL cholesterol was observed. In this study, a high-sucrose intake as part of an eucaloric, weight-maintaining diet had no detrimental effect on insulin sensitivity, glycemic profiles, or measures of vascular compliance in healthy nondiabetic subjects. Diabetes 55: 3566 -3572, 2006

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Aortic valve replacement results in significant health-related quality of life benefits across a broad range of health domains in elderly patients. Age alone should not be a precluding factor for surgery. Data are heterogeneous and mostly retrospective. We recommend future studies based on consistent guidelines provided in this systematic review.

Deoxyribozymes, or DNA enzymes (DNAzymes), are novel nucleic acids that have the ability to bind to specific sequences of RNA, and to cleave the target site catalytically. DNAzymes are smaller and more efficient enzymatically than ribozymes (RZs), which are catalytic nucleic acids synthesized from ribonucleotides. We have designed three DNAzymes that specifically target the two variants of the p210 bcr-abl gene (splice 1, b3a2; splice 2, b2a2) and the p190 variant (ela2). The cleavage sites for these DNAzymes are located 5 nucleotides (nt) 5' from the fusion site for b3a2, and only 1 nt 5' from the fusion sites for b2a2 and e1a2. We have shown in cell-free in vitro cleavage assays that these DNAzymes efficiently cleave their respective substrates. Mutated DNAzymes, in which only one critical base has been altered, do not cleave these targets. We have used a serum-resistant cytofectin (GS 2888; Gilead) to transfect the DNAzymes into target K562 cells, which express p210bcr-abl. In short-term transfection assays, the DNAzymes specifically inhibited p210bcr-abl protein expression by K562 cells by about 40%, and inhibited cell growth by more than 50% in a 6-day liquid culture assay. We have also transfected freshly isolated CD34+ bone marrow cells from patients with CML with the DNAzymes, which specifically inhibited the growth of bcr-abl-positive CFU-Mix colonies by 53-80%. The potential advantages of anti-bcr-abl DNAzymes over RZs include the following: DNAzymes are much less expensive to synthesize; they are more resistant to serum; and the anti-b2a2 DNAzyme cleaves at a site only 1 nt away from the fusion site, whereas its hammerhead RZ counterpart cleaves this target at a site 8 nt 3' to the fusion site, well within abl exon 2. DNAzymes are novel RNA-cleaving molecules that may significantly improve our ability to inhibit bcr-abl oncogene expression in Ph-positive target cells.

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Chronic myeloid leukemia (CML) is characterized by a reciprocal chromosomal translocation between chromosomes 9 and 22 t(9;22)(q34;q11) that causes fusion of the bcr and abl genes. Transcription and splicing of the fusion gene generate two major splice variants of the bcr/abl transcript that encode an oncoprotein with tyrosine kinase activity. We have taken advantage of lentiviral vectormediated delivery of anti-bcr/abl short hairpin RNAs (shRNA) to downregulate the bcr/abl transcript in Philadelphia chromosome-positive (Ph+) K562 leukemia cells. This downregulation caused complete inhibition of proliferation of these cells and was accompanied by >90% inhibition of the bcr/abl transcript and p210 protein. These results demonstrate the feasibility of using a lentiviral vector to stably transduce therapeutic shRNAs into leukemia cells for the potential ex vivo purging of Ph+ cells in an autologous hematopoietic cell transplant setting. Furthermore, the robust expression of the shRNAs from our lentiviral vector suggests that this system could be generally useful for the expression of other shRNAs.

A case of a patient with chronic myeloid leukemia whose cells expressed an e13a3 (b2a3) variant BCR-ABL p210 mRNA is presented. The variant splice was detected by a qualitative reverse transcriptase polymerase chain reaction using primers complementary to BCR exon 13 (b2) and ABL exon 3 (a3). The patient responded well to imatinib and achieved a complete cytogenetic response. Am. J. Hematol. 75:92-95, 2004.