ABSTRACT
Silica based nanoparticles are used in various fields of medical sciences to diagnose, control disease, for genetic disorders, owing to their size, surface area, biocompatibility and low toxicity. In dentistry, silica nanoparticles have been used as dental filler, teeth whitening agent but limited evidence is there regarding antimicrobial activity against oral pathogens. Therefore, the current study was conducted to assess the anti-bacterial activity of mouthwash incorporated with silica nanoparticles against oral pathogens. Tetraethoxysilane, ammonium hydroxide, absolute ethanol were used and centrifuged to obtain the silica nanoparticle pellet. XRD analysis was done to confirm the characterization of the thus obtained silica nanoparticle. The mouthwash was prepared with the synthesized silica nanoparticle as the main constituent. Agar well diffusion method was used to assess the antimicrobial activity against S. mutans, S. aureus and E. faecalis. The XRD analysis confirmed the amorphous nature of the synthesized silica nanoparticles.The zone of inhibition was found to increase as the concentrations increased mainly for S. aureus and E. faecalis. The synthesized nanoparticles incorporated mouthwash showed good potential as antimicrobial agents against strains of gram positive bacteria. Further animal studies/in vivo research should be conducted to validate the above findings
ABSTRACT
BACKGROUND: Arterial level repair is considered the most appropriate procedure for transposition of the great arteries. This report describes our experience with the arterial switch operation over the past decade. METHODS AND RESULTS: From January 1991 to January 2001, a total of 299 patients underwent an arterial switch operation for transposition of the great arteries or double-outlet right ventricle. Group I (n=169, 56.5%) comprised patients with transposition of the great arteries in whom the ventricular septum was essentially intact. Group II patients (n=130, 43.5%) had transposition of the great arteries with an additional significant ventricular septal defect or had double-outlet right ventricle with a subpulmonic ventricular septal defect. Of the total, 245 (82%) were males and 54 (18%) were females. In group I, the ages ranged from 2 days to 18 years (median 19 days) and weight ranged from 1.7 to 68 kg (median 2.5 kg). In group II, the ages ranged from 4 days to 4 years (median 90 days) and weight ranged from 2.5 to 17 kg (median 4 kg). Fifteen percent of the patients (25/169) in group I and 30% of the patients (39/130) in group II had features of bacteriologic infection. Arterial switch operation was performed on standard lines. In group I, 141 patients (83.4%) had a primary arterial switch operation while 28 (16.6%) underwent a rapid two-stage repair. Twenty-three patients required concomitant relief of associated anatomic left ventricular outflow tract obstruction. Operative mortality was 8.8% (15/169) in group I and 33% (44/130) in group II with an overall mortality of 19% (59/299). The major causes of operative mortality included pulmonary arterial hypertensive crisis (n=21), sepsis and related complications (n=16), and left ventricular failure (n=8). Coexisting arch anomalies, longer cross-clamp time, late presentation, and preoperative bacteriologic infections were incremental risk factors. Follow-up ranged from 1 to 10 years and was 87% complete. On follow-up, 91% of the patients were asymptomatic and off all medications. There were 3 late deaths and 5 patients required reoperation. CONCLUSIONS: Excellent long-term results are obtained in operative survivors following the arterial switch operation. However. operative mortality remains a concern in our set-up.