Neonatal repair of truncus arteriosus: continuing improvement in outcomes

BACKGROUND: Repair of truncus arteriosus in the neonatal and early infant periods has become standard practice at many centers. We reviewed our recent experience with repair of truncus arteriosus in neonates, with a focus on early and intermediate outcomes. METHODS: From July 1992 to December 1999, 65 patients 1 month of age or less underwent primary complete repair of truncus arteriosus. Median age was 10 days, and median weight was 3.2 kg. Major associated anomalies included moderate or severe truncal valve regurgitation in 15 patients (23%), interrupted aortic arch in 8 (12%), coronary artery abnormalities in 12 (18%), and nonconfluence of the pulmonary arteries in 3 (5%). Median durations of cardiopulmonary bypass and cardioplegic arrest were 172 minutes and 90 minutes, respectively. Circulatory arrest was employed only in 7 patients undergoing concomitant repair of interrupted arch. Reconstruction of the right ventricular outflow tract was achieved with an aortic (n = 39) or pulmonary (n = 26) allograft valved conduit (median diameter, 12 mm). Replacement (n = 6) or repair (n = 5) of a regurgitant truncal valve was performed in 11 patients, and interrupted arch was repaired in 8. RESULTS: There were three early deaths (5%). Early reoperations included reexploration for bleeding in 3 patients, emergent replacement of a pulmonary outflow conduit that failed acutely in 1 patient, and placement of a permanent pacemaker in 1. Mechanical circulatory support was required in 1 patient. During the median follow-up of 32 months, there were two deaths. The Kaplan-Meier estimate of survival was 92% at 1 year and beyond. The only demographic, diagnostic, or operative factors significantly associated with poorer survival over time were operative weight of 2.5 kg or less (p = 0.01) and truncal valve replacement (p = 0.009). Actuarial freedom from conduit replacement among early survivors was 57% at 3 years. CONCLUSIONS: Repair of truncus arteriosus in the neonatal period can be performed routinely with excellent survival, even in patients with major associated abnormalities.     

Peptide surface modification of methacrylamide chitosan for neural tissue engineering applications

Nerve fibres are guided to their targets by the combined actions of chemotactic and haptotactic stimuli; however, translating these stimuli to a scaffold that will promote nerve regeneration is nontrivial. In pursuit of this goal, we synthesized and characterized cell-adhesive, biodegradable chitosan scaffolds. Chitosan amine groups were reacted with methacrylic anhydride resulting in a water soluble methacrylamide chitosan (MC) that was then crosslinked by radical polymerization resulting in a scaffold. Biodegradability by lysozyme and penetrability of the scaffold by rat superior cervical ganglion (SCG) neurons were studied. Maleimide-terminated cell adhesive peptides, mi-GDPGYIGSR and mi-GQASSIKVAV, were coupled to a thiolated form of MC to promote cell adhesion. The MC scaffold was found to be porous, biodegradable, and to allow neurite penetration. Interestingly, all of these properties were found to depend upon the amount of initiator used in crosslinking. Covalent modification of the MC scaffold with cell adhesive peptides significantly improved neuronal adhesion and neurite outgrowth. The MC can be crosslinked to form a novel scaffold, where our results demonstrate its suitability in neural tissue engineering and its potential for other engineered tissues, such as cartilage repair, where chitosan has already demonstrated some utility.     

Preclinical and clinical evaluation of intraductally administered agents in early breast cancer

Most breast cancers originate in the epithelial cells lining the breast ducts. Intraductal administration of cancer therapeutics would lead to high drug exposure to ductal cells and eliminate preinvasive neoplasms while limiting systemic exposure. We performed preclinical studies in N-methyl-N'-nitrosourea-treated rats to compare the effects of 5-fluorouracil, carboplatin, nanoparticle albumin-bound paclitaxel, and methotrexate to the previously reported efficacy of pegylated liposomal doxorubicin (PLD) on treatment of early and established mammary tumors. Protection from tumor growth was observed with all five agents, with extensive epithelial destruction present only in PLD-treated rats. Concurrently, we initiated a clinical trial to establish the feasibility, safety, and maximum tolerated dose of intraductal PLD. In each eligible woman awaiting mastectomy, we visualized one ductal system and administered dextrose or PLD using a dose-escalation schema (2 to 10 mg). Intraductal administration was successful in 15 of 17 women with no serious adverse events. Our preclinical studies suggest that several agents are candidates for intraductal therapy. Our clinical trial supports the feasibility of intraductal administration of agents in the outpatient setting. If successful, administration of agents directly into the ductal system may allow for "breast-sparing mastectomy" in select women.     

Evaluation of a taste sensor instrument (electronic tongue) for use in formulation development

A taste sensor instrument (electronic tongue) was evaluated to determine its utility in developing a taste-enhanced liquid formulation. To train the electronic tongue, human sensory panel data were collected for two prototype formulations, a solution of the drug in water and several marketed products. Studies using the electronic tongue were conducted to determine taste-masking effectiveness of formulations compared to a matching placebo, to establish correlation with human sensory data, and to evaluate unknown formulations and predict their bitterness scores. In the first experiment, the effectiveness of a proposed taste-masking strategy was determined by comparing formulation prototypes containing a bitter active pharmaceutical ingredient (API) against corresponding placebos (i.e. formulations without an active ingredient) using electronic tongue data. The analysis of the electronic tongue data was based on the assumption that the drug was well taste masked if the placebo matched the formulation with API. In a second set of experiments, electronic tongue data were compared to existing data from a human taste panel for several marketed products and prototype formulations. A good correlation (r(2)=0.99) was achieved from this comparison, and the relative taste of prototype formulations not tasted by humans was predicted.     

Pre-procedural antibiotics for endoscopic urological procedures: Initial experience in individuals with spinal cord injury and asymptomatic bacteriuria

Objective

The objective of this study was to compare the safety, efficacy, quality-of-life impact, and costs of a single dose or a longer course of pre-procedural antibiotics prior to elective endoscopic urological procedures in individuals with spinal cord injury and disorders (SCI/D) and asymptomatic bacteriuria.

Design

A prospective observational study.

Setting

Hunter Holmes McGuire Veterans Affairs Medical Center, Richmond, Virginia, USA.

Participants

Sixty persons with SCI/D and asymptomatic bacteriuria scheduled to undergo elective endoscopic urological procedures.

Interventions

A single pre-procedural dose of antibiotics vs. a 3–5-day course of pre-procedural antibiotics.

Outcome measures

Objective and subjective measures of health, costs, and quality of life.

Results

There were no significant differences in vital signs, leukocytosis, adverse events, and overall satisfaction in individuals who received short-course vs. long-course antibiotics. There was a significant decrease in antibiotic cost (33.1 ± 47.6 vs. 3.6 ± 6.1 US$, P = 0.01) for individuals in the short-course group. In addition, there was greater pre-procedural anxiety (18 vs. 0%, P < 0.05) for individuals who received long-course antibiotics.

Conclusion

SCI/D individuals with asymptomatic bacteriuria may be able to safely undergo most endoscopic urological procedures with a single dose of pre-procedural antibiotics. However, further research is required and even appropriate pre-procedural antibiotics may not prevent severe infections.