Effect of an exercise training program on endothelial dysfunction in diabetic and non-diabetic patients with severe chronic heart failure.

BACKGROUND: Endothelial dysfunction is found both in patients with chronic heart failure and in patients with insulin-treated type 2 diabetes mellitus. This endothelial dysfunction leads to a significant reduction in endothelium-derived vasodilation. Physical exercise can have a positive effect on endothelial dysfunction in patients with coronary artery disease, chronic heart failure and diabetes mellitus. It is not clear, however, whether an exercise program influences endothelial function in diabetics with chronic heart failure. Our study was thus aimed at investigating whether a special exercise program would affect endothelial function. Comparisons were made with insulin-treated type 2 diabetics and with non-diabetics suffering from chronic heart failure. METHODS: 42 patients with severe chronic heart failure (LVEF < or = 30%), insulin-dependent diabetics (n=20, mean age 67+/-6 yrs, 16 male, 4 female), non-diabetics (n=22, mean age 68+/-10 yrs, 20 male, 2 female) participated in a 4-week exercise program consisting of ergometer and special muscle strength training. Before (T1) and at the end (T2) of the training program endothelium-dependent and endothelium-independent vasodilatory capacity were assessed by brachial artery diameter measurement. RESULTS: At the end of the training program, there were no significant results within the two groups. The endothelium-dependent vasodilation changed between T1 and T2 as follows: In the diabetic group, the endothelium-dependent vasodilation at T1 and T2 was 5.1+/-3.6 and 4.9+/-2.5%, respectively. For the non-diabetics, the endothelium-dependent vasodilation was 6.8+/-4.5 and 7.6+/-4.0% at T1 and T2, respectively. The endothelium-independent vasodilation in the diabetics was 10.5+/-5.6 at T1 and dropped to 8.7+/-4.1% at T2. The results for the non-diabetics were 13.2+/-5.8 and 12.3+/-6.3% at T1 and T2, respectively. The LVEF in the diabetics was 24.2+/-3.4% at T1, increasing to 27.8+/-5.8% at T2. In the non-diabetics, the LVEF was 22.9+/-3.8 at T1 vs. 28.6+/-6.9% at T2. In the groups of diabetics, the maximum oxygen uptake (VO2-max) was 10.3+/-3.9 at T1 vs. 11.4+/-2.8 ml/kg/min at T2 and in the group of non-diabetics 10.0+/-3.1 vs. 13.5+/-5.0 ml/kg/min. No correlations were found between the change in endothelium-dependent vasodilation and the increase in oxygen uptake. CONCLUSION: In our study, a program of physical exercise had no influence on endothelium-dependent or endothelium-independent vasodilation in insulin-treated type 2 diabetics or in non-diabetics with considerably reduced ejection fraction. In both groups, however, an exercise-related influence on medical parameters and physical performance could be observed.

Effects of education, self-care instruction and physical exercise on patients with chronic heart failure.

BACKGROUND: Evidence is now evolving of the importance of team management for patients with chronic heart failure. This includes education, patient self-care and physical exercise training. How such programs should be implemented is still under discussion. AIM: To assess the efficacy of an in-hospital rehabilitation clinic-based program, we studied its influence on cardiopulmonary parameters and quality of life in an outpatient setting. METHODS AND RESULTS: 75 patients (62 male, 13 female, mean age 65+/-8 years) underwent an exercise program including education, bicycle ergometer, muscle strength training and the 6-min walk test as a training unit for 4 weeks. Patients were studied at baseline (T1), before discharge (T2) and after a follow-up period of 29.9+/-5.5 weeks (T3). Baseline data (T1): left ventricular ejection fraction (LVEF): 33.8+/-7.6%, left ventricular end-diastolic volume (LVEDV): 130+/-51 ml, peak VO(2): 12.3+/-4.3 ml/kg, maximum work load (Watt max): 71+/-27 W. At discharge (T2) and follow-up (T3) LVEF increased to 36.8+/-8% and 41.8+/-9.2%, LVEDV decreased to 127+/-43 ml and 114+/-40 ml, peak VO(2) increased to 14.1+/-5.1 ml/kg and 15.2+/-5 ml/kg, and Watt max increased to 84+/-28 Wand 98+/-42 W (all p<0.01). Quality of life improved significantly at discharge and follow-up in nearly all domains and in the summary score for physical health. There were no significant changes for anxiety and depression at T2 and T3. CONCLUSION: A specialized in hospital rehabilitation program including education, patient self management and training has a sustained positive effect on cardiopulmonary parameters and physical well-being.

Ds excision from extrachromosomal geminivirus vector DNA is coupled to vector DNA replication in maize.

Analysis of transposition products generated after Activator (Ac) excision from the P locus in maize suggest that Ac excises either during or after replication of the P locus. The frequency of excision of the non-autonomous Ac derivative, Dissociation (Ds), from extrachromosomal replicating and nonreplicating vector DNAs in transfected black mexican sweet maize protoplasts was compared to assess directly a role of extrachromosomal vector DNA replication in Ds excision. Replicating (rep+) and nonreplicating (rep-) vector DNAs comprised a Ds element that harbored a geminivirus, wheat dwarf virus (WDV), origin of replication and WDV genes required for viral DNA replication (rep+) or mutant, inactive derivatives of these genes (rep-). Excision of Ds was detected only in those cell nuclei co-transfected with the replicating Ds-vector DNA and a transposase expression vector. Quantitative reconstruction experiments showed that Ds excised at least 3 x 10(5)-fold more frequently from replicating vector DNA as compared with nonreplicating vector DNA. Therefore, these results provide direct evidence for a coupling of Ds excision from extrachromosomal vector DNA to vector DNA replication in maize.

A system for insertional mutagenesis and chromosomal rearrangement using the Ds transposon and Cre-lox.

A system for insertional mutagenesis and chromosomal rearrangement in Arabidopsis has been developed. The T-DNA vectors are based on the maize transposon Ds, lox sites from the Cre-lox site-specific recombination system, and transcriptional fusions expressing Ac transposase or Cre recombinase. The engineered transposon is termed Dslox. Transposed Dslox insertions were created by crossing plants bearing Dslox with plants expressing Ac transposase, then simultaneously selecting for excision and reinsertion in F2 seedlings using the herbicides chlorsulfuron and phosphonothricin, respectively. F2 plants bearing stable Dslox insertions were identified by scoring for the absence of the Ac transposase T-DNA, using a novel, visual marker in that T-DNA. Two independent Dslox insertions were characterized and placed 5.6 and 16.5 cM from their T-DNAlox, which mapped close to m506 on chromosome 4. Plants bearing either of the two different transposed Dsloxs and T-DNAlox were crossed to plants expressing Cre recombinase, which catalyzed recombination between the lox site in transposed Dslox and the lox site in T-DNAlox. Lox-lox recombinants were identified selectively amongst progeny of these crosses. Molecular and genetic analysis of the lox-lox rearrangements indicated that both were inversions. The smaller inversion was germinally transmitted from generation to generation as a simple trait, whereas the larger inversion was not transmitted to progeny of plants bearing the rearrangement.

Wheat dwarf virus Ac/Ds vectors: expression and excision of transposable elements introduced into various cereals by a viral replicon.

The maize transposon Activator (Ac) and in vitro-generated nonautonomous derivatives thereof [Ac delta or Dissociation (Ds) elements] were inserted into the genome of a geminivirus of graminaceous plants, wheat dwarf virus, at a site that does not interfere with viral replication. These recombinant viral genomes were introduced into wheat, maize, and rice protoplasts, where rapid and efficient excision of Ac was observed. Excision was detected only in vectors in which, after transfection, the virus could replicate. This result is not restricted to the autonomous Ac; excision of Ds elements was also induced by transposase activity provided in trans by plasmids expressing the cDNA of Ac. The potential of this combination of a transposon with a viral replicon for plant molecular genetic engineering is discussed.

Recombination of selectable marker DNA in Nicotiana tabacum.

A chimeric neomycin phosphotransferase II (NPT II) gene, which normally provides kanamycin resistance to transformed plant cells, was inactivated by in vitro deletions. Repair plasmids not containing plant-specific transcription signals but containing only the NPT II coding region (or parts of it) were used in co-transformation experiments involving direct DNA uptake into protoplasts isolated from Nicotiana tabacum. Recombination, or gene conversion mediated by homologous sequences produced active NPT II genes in about 1% of transformants, rendering these cells resistant to kanamycin. Analysis of the size of the active enzyme indicated that recombination had occurred producing an NPT II gene indistinguishable from the wild-type gene. Southern blot analysis revealed that the bulk of co-transformed donor plasmid DNA had suffered structural modifications; however, kanamycin resistance was inherited in a Mendelian fashion, indicating that at least one functional and structurally intact copy of the regenerated NPT II gene is integrated into the host genome.

Studies of the structure and functional organization of foreign DNA integrated into the genome of Nicotiana tabacum.

In transgenic plants obtained either by Agrobacterium tumefaciens-mediated transformation or by direct DNA transfer, the structure of integrated chimeric donor DNA remains stable during vegetative proliferation, during sexual transmission, and under various selection conditions. We correlate the level of expression of the introduced gene in independent transformants and their offspring with the particular arrangement and modification of their integrated DNAs. Genetic analysis of transgenic plants shows that the chimeric gene is transmitted in a Mendelian fashion to the F1 and F2 progeny as a single dominant trait. Deviations from the expected segregation pattern are discussed with respect to different levels of gene activity. We compare the gene activity in heterozygotes versus homozygotes, and show variation in activity between plants regenerated independently from the same transformed callus. Cotransformation studies with two physically unlinked and partly homologous plasmids carrying two different marker genes indicate that they are physically linked after integration into the host genome.