The effectiveness of transmeatal low-power laser stimulation in treating tinnitus.

The aim of this study is to examine the effectiveness of transmeatal low-power laser stimulation (TLLS) in treating tinnitus. This is a prospective, double-blinded, randomized, placebo-controlled trial. Patients with persistent subjective tinnitus as their main symptom were recruited into the study from the outpatient clinics. The recruited patients were randomized into the experimental group or TLLS+ group (patients in this group were prescribed to use TLLS at 5 mW at 650 nM wavelength for 20 min daily and oral betahistine 24 mg twice per day for a total of 10 weeks) and the control group or TLLS- group (patients in this group were prescribed with a placebo device to use and oral betahistine 24 mg twice per day for 10 weeks). All patients were required to answer two sets of questionnaires: the Tinnitus handicap inventory (THI) and visual analogue scales (VAS) symptoms rating scales, before starting the treatment and at the end of the 10-week treatment period. The total score of the THI questionnaire was further graded into five grades, grade 1 being mild and grade 5 being catastrophic. Wilcoxon-signed ranks test and Mann-Whitney test were used to compare and analyze the THI and VAS scores before and after treatment for each group. Changes with p value of <0.05 were considered as statistically significant. Chi square test was used to analyze the change of parameters in categorical forms (to compare between TLLS+ and TLLS-). Changes with p value of <0.05 were considered as statistically significant. Forty-three patients successfully and diligently completed their treatment. It was noted that using any condition of the device, TLLS+ or TLLS-, patient's tinnitus symptoms improved in terms of THI scores (TLLS+, p value = 0.038; TLLS-, p value = 0.001) or VAS scores with a change of at least one grade (TLLS+, p value = 0.007; TLLS-, p value = 0.002) at p value <0.05 significant level. In contrast when TLLS+ group was compared with TLLS- group, no statistically significant result was obtained. In term of VAS scores, there seems to be no statistically significant improvement in patients' annoyance, sleep disruption, depression, concentration and tinnitus loudness and pitch heard between the two groups. Transmeatal low-power laser stimulation did not demonstrate significant efficacy as a therapeutic measure in treating tinnitus.

Velopharyngeal and choanal stenosis after radiotherapy for nasopharyngeal carcinoma.

Choanal stenosis is a well recognized late complication of radiotherapy for nasopharyngeal carcinoma. However velopharyngeal stenosis post radiotherapy for nasopharyngeal carcinoma is rare. We present here a case of bilateral choanal stenosis and velopharyngeal stenosis in a patient treated with radiotherapy for nasopharyngeal carcinoma. A 58-year-old woman presented to our otolaryngology clinic with a one year history of nasal obstruction. She was diagnosed to have nasopharyngeal carcinoma 12 years ago for which she received radiotherapy. Clinical examination revealed bilateral choanal stenosis and velopharyngeal stenosis. Treatment of choanal stenosis and velopharyngeal stenosis is challenging due to high incidence of recurrence and patients frequently require multiple procedures. The patient underwent a transnasal endoscopic excision of velopharyngeal scar tissue and widening of posterior choana using Surgitron®, mitomycin-C applied topically to the surgical wound and bilateral stenting under general anesthesia. The stents were kept for two weeks, and 3 years post operation velopharyngeal aperture and posterior choana remained patent. As illustrated in this case velopharyngeal stenosis can occur after radiotheraphy and should not be overlooked. Combine modality of transnasal endoscopic excision of velopharyngeal scar tissue, widening of choanal stenosis with Surgitron® followed by the application of mitomycin-C and stenting has been shown to be an effective option.

Size-dependent two-photon excitation photoluminescence enhancement in coupled noble-metal nanoparticles.

Plasmon coupling is known to enhance the two-photon excitation photoluminescence of metal nanoparticles significantly. Here, Au and Ag nanospheres of different sizes were prepared to systematically investigate the effects of particle size on plasmon coupling enhanced two-photon excitation photoluminescence. An oppositely charged polyelectrolyte, poly(diallyldimethylammonium chloride) (PDDA), was used to induce the coupling of Au and Ag nanospheres. The two-photon excitation photoluminescence enhancement factor was found to first increase and then decrease with the increasing particle size for both Au and Ag nanospheres. Optimum enhancement factors of 25-fold and 14-fold were obtained for coupled 55-nm Au nanospheres and 50-nm Ag nanospheres, respectively. The coupled Au and Ag nanospheres displayed two-photon action cross sections of up to 9 × 10(4) GM per particle (where 1 GM = 10(-50) cm(4) s/photon). Similar to Ag nanoparticles, Au nanoparticles also displayed large coupling induced enhancement of two-photon excitation photoluminescence. Considering their excellent biocompatibility, high inertness, and easy preparation, Au nanoparticles are expected to find many new applications in two-photon biosensing and bioimaging.