Toru Matsunaga

Background/Objectives Conventional eye drops are the primary therapeutic option for ocular diseases; however, their clinical utility is hindered by several drawbacks, including limited bioavailability and suboptimal patient compliance. To overcome these challenges, we designed a sustained-release contact lens (CL) device loaded with tranilast (TRA) and determined whether the TRA-laden CL could provide sustained drug delivery to the lacrimal fluid and aqueous humor. Methods TRA nanocrystals were prepared using the bead-milling approach. Using three types of CLs (nonionic, anionic, and cationic), we prepared TRA-laden CLs by employing a combination of solid TRA nanocrystals and soaking methods under high-temperature and high-pressure conditions in an autoclave (the hThP method). Male Japanese albino rabbits (2–3 kg) were used to evaluate the CLs. Results Bead milling reduced the size of the solid TRA nanoparticles (STNs) to approximately 35–180 nm. The TRA-laden cationic CLs prepared using STNs and the hThP method contained a higher amount of TRA than those prepared using the corresponding conventional soaking method. The CLs prepared using the hThP method remained transparent after drug loading. Compared with nonionic and anionic CLs, cationic CLs had the highest drug-loading capacity and allowed for sustained drug release. Moreover, STNs were observed in the released TRA, with no corneal damage or light scattering detected in the rabbits’ eyes. TRA-laden cationic CLs prepared using the hThP method achieved sustained and higher drug delivery into the lacrimal fluid and aqueous humor than those prepared using the conventional soaking method. Conclusions Our findings suggest that TRA-laden cationic CLs prepared using STNs and the hThP method can overcome the challenges associated with the conventional soaking method, including low drug uptake and high burst release.

Objectives: This study evaluated the design of a sustained-release contact lens (CL) device loading tranilast (TRA) and determined the usefulness of these CLs in Japanese albino rabbits. Methods: The sustainable CLs in this study were prepared by combining three CLs with different water contents and soaking methods under high-pressure and high-temperature using an autoclave method (AC-method). Results: Both the CLs prepared with the conventional soaking method (stir-method) and AC-methods were transparent in all three types of CLs. The loaded TRA contents in the CLs when using the AC-method were higher than those prepared using the stir-method for all three types of CLs. TRA contents were also higher when loaded into the cation-type lenses as compared to the other lenses. Moreover, the sustainable release of TRA from the TRA-loaded cation-type CL using the AC-method was significantly higher than those found for the other CLs. No corneal wounds were observed in any of the rabbits given the three types of TRA-loaded CLs for 7 days. Furthermore, the TRA-loaded CL sustainably released TRA into the lacrimal fluid in the rabbit. Conclusions: The TRA-loaded CL prepared using the AC-method overcame the limitations normally associated with the stir-method, such as the high burst release and low drug uptake.

This study aimed to compare the in vitro and in vivo retention, bacterial adhesion, and biofilm formation between anionic and zwitterionic bandage contact lenses (BCLs) in healthy canines. BCL retention and tolerance were evaluated in 10 healthy canines via a single-masked, crossover study for 7 days. To compare in vitro bacterial adhesion and biofilm formation, four Staphylococcus strains were incubated with the BCLs at 37 °C for 2 or 24 h, and the bacterial colony forming units (CFUs) adhering to the BCLs were counted. Next, to compare in vivo bacterial adhesion, the CFUs of bacteria adhering to the BCLs worn by canines for 24 h were counted. Anionic lenses significantly retained and reduced in vitro bacterial adhesion than in the zwitterionic lenses. However, the amount of in vitro biofilm formation was more likely to be higher on anionic lenses than on zwitterionic lenses. In vivo bacterial adhesion was not significantly different between the two types of BCLs. Nevertheless, both BCLs were well-tolerated by the canines; thus, their short-term use in dogs can be recommended as safe.

Much attention has been paid to hearing results after stapes surgery, but the risks of vestibular disturbance has not been extensively studied. Postoperative spontaneous nystagmus was measured daily at bedside by portable ENG in order to evaluate the vestibular damage from stapes surgery. Thirteen patients underwent primary stapedotomy or stapedectomy from August 1, 1992 to June 30, 1993. Nystagmus toward the operated ear was observed in 3 cases, that toward the opposite ear in 2 cases, that changing from toward the operated ear to toward the opposite ear in 2 cases, that changing from toward the opposite ear to toward the operated ear in 2 cases and no nystagmus in 4 cases. There was no relationship between duration of nystagmus and that of dizziness. Nystagmus was thought to be due to the following: i) inner ear damage by operation, ii) postoperative perilymphatic fistula, iii) floating footplate, and iv) stimulation of hair cells by high potassium ion in the perilymph due to blood flow into the inner ear.

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We attempted to determine the relationship of nasal polyps to histamine (HA) metabolism. Compared to that in allergy-related nasal polyps and infection-related nasal polyps, the level of HA in aspirin-induced asthma—related polyps was significantly lower. Large differences between the groups were not observed in HA-synthesizing enzyme activity, but degradative enzyme activity was much higher in aspirin-induced asthma—related polyps than in other types of nasal polyps tested. These findings suggest the possibility that the amount of HA in polyps associated with aspirin-induced asthma was less because of greatly enhanced degradation. We found, in addition, that in nasal tissues such as polyps, histamine-N-methyl transferase, rather than histaminase, was the principal degradative enzyme.

Fifty-five ear of 49 patients with otosclerosis were operated on with either large fenestra stapes (stapedectomy; SDE) or small fenestra stapes (stapedotomy; STO) surgery. Pre-operative average hearing levels for the speech frequency ranges (0.5,1,2 kHz) were 56.1 dBHL for SDE and 61.0 dBHL for STO. These improved to 39.0 dBHL and 35.0 dBHL. Statistically, significant hearing recovery was obtained for a frequency range from 0.125 to 2 kHz for SDE and from 0.125 to 4 kHz for STO (p < 0.05, Dunnett's multiple variance test). The degree of post-operative hearing improvement for STO was significantly higher at 0.5, 2 and 8 kHz than that for SDE (p < 0.05, Student's t-test). A pre-operative speech discrimination score of 80% was obtained at 68.9 dB for SDE and at 76.0 dB for STO. These values improved to 56.1 dB and 49.5 dB post-operatively. Thus, it was proved that STO results in better hearing than SDE does.

Two kinds of experimental endolymphatic hydrops were produced:one was induced by obstruction of the endolymphatic sac, and the other was induced by systemic KLH immunization and secondary KLH challenge into the endolymphatic sac. Vascular permeability of the stria vascularis was compared in the two models by light and electron microscopy using the tracer horseradish peroxidase (HRP) method. The ratios of capillaries showing HRP leakage to capillaries observed were 7/33 in the endolymphatic sac obliteration model, 36/39 in the secondary challenged side, and 13/37 in the non-secondary challenged side of the immunologically induced model. Permeability to HRP was significantly higher in the secondary challenged side than in either the endolymphatic sac obliteration model or the non-secondary challenged side. The present study raises the possibility that endolymphatic hydrops is induced by overproduction of endolymph.

Infections constitute a high percentage of the diseases treated in the field of otorhinolaryngology. We examined the efficacy and safety of Banan® and the trends of the organisms causing infections in 300 patients. A total of 262 strains of organisms were detected and S. aureus was predominant. The efficacy rate of Banan® was 89.5% for acute infections, 62.8% for chronic ones, and 76.5% overall. Side effects occurred in 2.7% of the patients and the majority of them were gastrointestinal disorders. Thus, we concluded that this drug was useful in the field of otorhinolaryngology.