PrimerSelect: a transcriptome-wide oligonucleotide primer pair design program for kinetic RT-PCR-based transcript profiling.

We describe PrimerSelect, a program capable of transcriptome-wide design of primer pairs for optimal performance in kinetic reverse-transcriptase polymerase chain reaction (RT-PCR). For the yeast Saccharomyces cerevisiae, PrimerSelect designs primer pairs for 86% of genomic open reading frames (ORFs) using design criteria we previously established to be optimal for kinetic RT-PCR (kRT-PCR)-based transcript quantitation. Primer pairs designed by PrimerSelect for 230 yeast ORFs were evaluated for primer dimer potential, PCR cyclewise yield, and cross-priming. Performance of 95% of these primer pairs is optimal with respect to primer dimer potential and PCR cyclewise yield for quantitating even the rarest yeast transcript. All of the primer pairs produced a single amplicon of the expected size from yeast genomic DNA template. The utility of PrimerSelect for designing primer pairs complementary to ORF sequences defined for multiple isolates of the human bacterial pathogens Helicobacter pylori and Staphylococcus aureus is also demonstrated.

Tricuspid valve replacement: bioprosthetic or mechanical valve?

Significant morbidity and mortality is associated with tricuspid valve replacement, and controversy still exists as to the ideal prosthesis in this position. This study aimed to identify the risk factors for low cardiac output and mortality, and whether bioprosthetic or mechanical valves perform better in the tricuspid position. Results of 121 tricuspid valve replacements in 104 patients between January 1966 and December 2002 were reviewed. Most patients were in New York Heart Association functional class III or IV. Perioperative mortality was 19%. On multivariate analysis, age and preoperative jaundice were significant predictors of low cardiac output; age, jaundice, atrial fibrillation, and bypass time were significant predictors of mortality. Mechanical valves were significantly more prone to thromboembolism, whereas bioprostheses suffered structural valve deterioration. There were no significant differences in anticoagulation or bleeding episodes between the two groups, nor in valve-related events, deaths, and long term survival. There was no significant difference in performance so as to recommend one type over the other, but bioprosthetic valves may be more favorable as they fail predictably.

Biatrial or bicaval technique for orthotopic heart transplantation: which is better?

BACKGROUND: Orthotopic heart transplantation was done by the biatrial technique initially and the bicaval technique has become popular recently. AIMS: This study aims to determine if bicaval technique is advantageous. METHODS: Consecutive transplants performed between 1996 and 2001 were divided into two groups-37 patients done by bicaval and 38 by biatrial technique. Data accumulation was by retrospective study of patient charts. RESULTS: Both groups had similar preoperative variables. There were no differences in low cardiac output (18.9% versus 26.3%, p = 0.62), intraaortic balloon pump insertion (16.2% versus 15.7%, p = 1.0), re-exploration (13.5% versus 18.4%, p = 0.79) and perioperative mortality (5.4% versus 7.9%, p = 1.0) in the bicaval versus biatrial groups. Temporary (13.5% versus 39.4%, p = 0.15) and permanent pacing (0 versus 3 patients) tended to be less frequent and central venous pressure measured at 1-week was lower in the bicaval group (mean 13.8 +/- 6cm versus 14.9 +/- 5.4cm, p = 0.42), but not attaining statistical significance. Severe tricuspid regurgitation was seen in one bicaval versus five biatrial patients at follow-up. CONCLUSIONS: Though bicaval group tended to require less pacing, had less tricuspid regurgitation and had lower central venous pressures, these did not attain statistical significance. There were otherwise no obvious differences in outcome. SHORT ABSTRACT: Seventy five consecutive orthotopic heart transplantations done during the period 1996-2001 by bicaval or biatrial surgical technique were compared. There was no difference in low cardiac output, intraaortic balloon pump insertion and mortality but the bicaval patients tended to have less pacing and diuretic requirements and lower central venous pressures, though not attaining statistical significance.