Male Sex Associated with Increased Long-term Cardiovascular Mortality after Peripheral Vascular Surgery for Atherosclerosis Despite Optimal Medical Treatment.

BACKGROUND: The cardiovascular burden and consequences of peripheral atherosclerosis appear to differ between men and women. Data regarding long-term outcomes, including the impact of medical prophylactic treatment, are insufficient. This study examined long-term outcomes according to sex following primary vascular surgery, adjusted for multiple variables as well as recommended medical prophylaxis. METHODS: All Danish patients who underwent peripheral vascular surgery from January 2000 to December 2007 were stratified into five procedural groups: (a) aorto-iliac bypass or thromboendarterectomy, (b) femoro-femoral crossover, (c) thromboendarterectomy of the femoral arteries, (d) infrainguinal bypass, or (e) axillo- uni-, and bifemoral bypass. Data were analyzed according to sex for differences in myocardial infarction, stroke, and death, individually and combined, after surgery. RESULTS: A total of 11,234 patients were included: 6,289 males and 4,945 females. The overall adjusted hazard ratio for male patients compared with female patients for death was 1.11 (95% CI 1.06-1.17), for MI was 1.16 (95% CI 1.04-1.29), for stroke was 0.99 (95% CI 0.89-1.11), and for any major adverse cardiovascular event was 1.10 (95% CI 1.05-1.16). CONCLUSIONS: These findings show that, despite indication, severity, and concomitant medical treatment of peripheral artery disease, men have a higher risk of mortality and adverse cardiovascular events following surgery for peripheral arterial disease.

A major deletion in the cucumber mitochondrial genome sorts with the MSC phenotype.

The cucumber mitochondrial genome is unique because of its large size, paternal transmission, and the existence of a paternally transmitted mosaic (MSC) phenotype spontaneously appearing after independent tissue culture experiments. Transmission studies eliminated paternal imprinting as the genetic basis for the MSC phenotype. We identified a 13 kb region (JLV5-DEL) in the wild-type mitochondrial genome that was absent from three MSC lines. This deleted region was paternally transmitted with the MSC phenotype through the F3 and test-cross generations. Southern hybridizations and PCR amplifications using primers within the JLV5 region revealed that rare wild-type sorters possessed the wild-type region. MSC plants possess the wild-type region at levels (approximately 0.002) below detection by standard PCR reactions and Southern hybridizations, using genomic DNA. Sequence analysis of the wild-type contig revealed no homologies to mitochondrial genes and no open reading frames within JLV5-DEL. PCR amplifications across JLV5-DEL using MSC mtDNA revealed that the loss of this region was not a simple deletion and may be associated with a rearrangement. Because no genic regions were identified within the wild-type JLV5 region, the specific lesion conditioning the MSC phenotype may be associated with the putative rearrangement or another mutation that occurred during tissue culture or exists substoichiometrically in the parental line and is transmitted together with JLV5 within the same mitochondrion.

Small, repetitive DNAs contribute significantly to the expanded mitochondrial genome of cucumber.

Closely related cucurbit species possess eightfold differences in the sizes of their mitochondrial genomes. We cloned mitochondrial DNA (mtDNA) fragments showing strong hybridization signals to cucumber mtDNA and little or no signal to watermelon mtDNA. The cucumber mtDNA clones carried short (30-53 bp), repetitive DNA motifs that were often degenerate, overlapping, and showed no homology to any sequences currently in the databases. On the basis of dot-blot hybridizations, seven repetitive DNA motifs accounted for >13% (194 kb) of the cucumber mitochondrial genome, equaling >50% of the size of the Arabidopsis mitochondrial genome. Sequence analysis of 136 kb of cucumber mtDNA revealed only 11.2% with significant homology to previously characterized mitochondrial sequences, 2.4% to chloroplast DNA, and 15% to the seven repetitive DNA motifs. The remaining 71.4% of the sequence was unique to the cucumber mitochondrial genome. There was <4% sequence colinearity surrounding the watermelon and cucumber atp9 coding regions, and the much smaller watermelon mitochondrial genome possessed no significant amounts of cucumber repetitive DNAs. Our results demonstrate that the expanded cucumber mitochondrial genome is in part due to extensive duplication of short repetitive sequences, possibly by recombination and/or replication slippage.

Instability of bacterial artificial chromosome (BAC) clones containing tandemly repeated DNA sequences.

The cloning and propagation of large DNA fragments as bacterial artificial chromosomes (BACs) has become a valuable technique in genome research. BAC clones are highly stable in the host, Escherichia coli, a major advantage over yeast artificial chromosomes (YACs) in which recombination-induced instability is a major drawback. Here we report that BAC clones containing tandemly repeated DNA elements are not stable and can undergo drastic deletions during routine library maintenance and DNA preparation. Instability was observed in three BAC clones from sorghum, rice, and potato, each containing distinct tandem repeats. As many as 46% and 74% of the single colonies derived from a rice BAC clone containing 5S ribosomal RNA genes had insert deletions after 24 and 120 h of growth, respectively. We also demonstrated that BAC insert rearrangement can occur in the early stage of library construction and duplication. Thus, a minimum growth approach may not avoid the instability problem of such clones. The impact of BAC instability on genome research is discussed.

Complex mtDNA constitutes an approximate 620-kb insertion on Arabidopsis thaliana chromosome 2: implication of potential sequencing errors caused by large-unit repeats.

Previously conducted sequence analysis of Arabidopsis thaliana (ecotype Columbia-0) reported an insertion of 270-kb mtDNA into the pericentric region on the short arm of chromosome 2. DNA fiber-based fluorescence in situ hybridization analyses reveal that the mtDNA insert is 618 +/- 42 kb, approximately 2.3 times greater than that determined by contig assembly and sequencing analysis. Portions of the mitochondrial genome previously believed to be absent were identified within the insert. Sections of the mtDNA are repeated throughout the insert. The cytological data illustrate that DNA contig assembly by using bacterial artificial chromosomes tends to produce a minimal clone path by skipping over duplicated regions, thereby resulting in sequencing errors. We demonstrate that fiber-fluorescence in situ hybridization is a powerful technique to analyze large repetitive regions in the higher eukaryotic genomes and is a valuable complement to ongoing large genome sequencing projects.

Cytogenomic analyses reveal the structural plasticity of the chloroplast genome in higher plants.

A DNA fiber-based fluorescence in situ hybridization (fiber-FISH) technique was developed to analyze the structure and organization of a large number of intact chloroplast DNA (cpDNA) molecules from Arabidopsis, tobacco, and pea. Using this cytogenomic approach, we determined that 25 to 45% of the cpDNA within developing leaf tissue consists of circular molecules. Both linear and circular DNA fibers with one to four copies of the chloroplast genome were present, with monomers being the predominant structure. Arabidopsis and tobacco chloroplasts contained previously unidentified multimers (>900 kb) consisting of six to 10 genome equivalents. We further discovered rearranged cpDNA molecules of incomplete genome equivalents, confirmed by both differential hybridizations and size estimations. The unique cpDNA organization and novel structures revealed in this study demonstrate that higher plant cpDNA is more structurally plastic than previous sequence and electrophoretic analyses have suggested. Additionally, we demonstrate how the fiber-FISH-based cytogenomic approach allows for powerful analysis of very rare events that cannot be detected by traditional techniques such as DNA gel blot hybridization or polymerase chain reaction.

Arthrodesis of the knee: experience with intramedullary nailing.

Knee arthrodesis using an intramedullary nail has gained acceptance as treatment in difficult cases such as infection after total knee arthroplasty (TKA), neuropathic joint, and obesity. A retrospective review of 22 cases treated at our institution using an intramedullary nail for knee arthrodesis was performed. Deep infection after primary (11) or revision (6) TKA was the most common indication for this procedure. A long intramedullary nail was used in 3 cases, a long nail with a proximal interlocking screw was used in 6 cases, and a customized nail with a valgus bend and a proximal interlocking screw was used in 11 cases. A modular knee fusion nail was used in 1 case. Successful fusion occurred in all cases, although 4 patients required additional surgery. Average operative blood loss was 748 mL, and average time to union was 7 months. Shortening of the extremity averaged 3.2 cm. Tibiofemoral alignment was improved by using a customized valgus nail (average, 3.1 valgus; range, 1-5) when compared with a straight nail (average, 0.2 valgus; range, 3 varus to 3 valgus). No patient developed infection in the hip or ankle region as a result of the long intramedullary nail. Intramedullary nailing is an excellent technique for knee arthrodesis in difficult cases. A customized proximal interlocking nail with 5 degrees to 7 degrees of valgus and 5 degrees of anterior angulation improves tibiofemoral alignment and is straightforward to insert or extract should it be necessary. Stability and pain relief are rapid, and the fusion rate is maximized.