Localization of sirtuins (SIRT1-7) in the aged mouse inner ear.

CONCLUSION: The expression of sirtuin in vestibular end organs and cochlea responds differently to age-related changes. Down-regulation of SIRT1, 3, and 5 in the cochlea may weaken the protective activity regarding degeneration of the organ of Corti as well as of spiral ganglion cells, resulting in the development of age-related hearing loss. An increase in SIRT 1, 4, or 5 in vestibular tissue could indicate an increased need of detoxification of reactive oxygen species and an increased anti-ageing potential. OBJECTIVE: To analyse the expression of sirtuins (SIRT1-7) in the normal young and old mouse inner ears. METHODS: Young (8 weeks) and old (22 months) CBA/J mice were used in this study. Localization of SIRT1-7 in the inner ear, i.e. cochlea, vestibular end organs, and vestibular ganglion, was investigated using real-time PCR and immunohistochemistry. RESULTS: In the vestibular end organs, the expression of SIRT1, 2, 4, 5 (both mRNA and protein), SIRT6, and 7 (only mRNA) was found to be increased, while a slightly decreased immunoreactivity was observed in SIRT3. In the cochlea, the expression of SIRT1, 3, and 5 (both mRNA and protein) was decreased in the old mice, whereas no noticeable difference was observed regarding SIRT2, 4, 6, or 7.

Long-term administration of vasopressin can cause Ménière's disease in mice.

CONCLUSION: A new murine model of Ménière's disease has been developed, based on long-term administration of vasopressin. Induction of vestibular dysfunction in the present animal model can cause additional stress, by reducing inner ear blood flow. Latanoprost, a selective agonist for the FP prostanoid receptor, may become a new remedy for Ménière's disease. OBJECTIVE: The purpose of this study was to develop a more suitable animal model, with a closer resemblance to the pathophysiological process in Ménière's disease. METHODS: Adult CBA/J or ICR mice were treated by subcutaneous injection of vasopressin for 5 days up to 8 weeks. Morphological analyses were performed of the cochlea, vestibular end organs and endolymphatic sac. The effect of latanoprost on the development of endolymphatic hydrops was also examined. RESULTS: All experimental animals showed mild to moderate endolymphatic hydrops, increasing in severity as the vasopressin treatment was prolonged. Animals treated with vasopressin for 8 weeks showed severe endolymphatic hydrops with partial loss of outer hair cells and spiral ganglion cells. These animals also had a reversible vestibular dysfunction following intratympanic injection of epinephrine. Latanoprost inhibited the development of endolymphatic hydrops caused by vasopressin.

[Clinical study of secondary cholesteatoma].

Acquired middle ear cholesteatoma is considered to be formed by retraction of the tympanic membrane. There are rare cases in which the tympanic membrane epidermis extends into the medial surface of the tympanic membrane from the margin of its perforation, namely so-called secondary cholesteatoma. We studied the cases of secondary cholesteatoma clinically. These cases were found in 13 of 419 ears (3.1%) with acquired middle ear cholesteatoma operated on in our hospital from March 2001 to October 2010. The average age of all the cases was 51.5 years old, with a range of 11-65 years. We adopted the canal wall down tympanoplasty procedure with canal reconstruction in all cases. The postoperative hearing improvement rate was 84.6%. There were no cases of recurrence of the cholesteatoma.

[A case of epiglottic NK/T cell malignant lymphoma].

We report a case of malignant epiglottic natural killer (NK)/T cell lymphoma. A 33-year-old man seen 1-month period for throat pain was found in endoscopic larynx examination to have inflammation with plaques and redness epiglottic. The 4 month period, right epiglottic inflammation showed progressive necrosis. The diagnosis of malignant lymphoma was confirmed by 3 biopsies. Laryngomicrosurgery specimens histologicalily showed moderate leukocytic infiltration mainly of atypical lymphocytes. Neoplastic cells were UHCL1+, CD3+, L26-, CD79a, and EBER-ISHW. Despite 4 units of DeVIC chemotherapy and regional irradiation, the man died of metastatis 1 year and 9 months after initial treatment. Among malignant laryngeal tumors, malignant epiglottic NK/T cell lymphoma is extremely rare, with only one case reported in the literature.

[Evaluation of soft diets using freeze infusion in videofluorography].

A food developed at the Hiroshima Prefectural Food Technology Research Center, Hiroshima, Japan, has proved to be a boon in videofluorography. The food features decreased hardness with retained their shape due to being impregnated with macerating enzymes under reduced pressure after vegetables are defrosted. Samples were removed immediately from the enzyme solution after freeze infusion. All foods tested raging from carrots to chicken contasted well in videofluorography in an evaluation of swallowing in 107 subjects with dysphagia, results for carrots compared well with those for 33% iopamidol, jelly, and yogurt. Only a subjects showed silent aspiration with carrots, compared to 19 with 33% iopamidol. Among 70 subjects showing no residual jelly and/or yogurt, just 12-8 severe and 4 moderate-showed residual carrots in the pharyngeal space. In contrast, among 67 subjects showing no residual carrots in the pharyngeal spase, 9 moderate subjects showing no residual jelly and/or yogurt. We concluded foods such as carrots treated as stated following jelly and/or yogurt as new nutrition sources for subjects with dysphagia.

Decreased visual function after patchy loss of retinal pigment epithelium induced by low-dose sodium iodate.

PURPOSE: To correlate damage to the retinal pigment epithelium (RPE) with decreased visual function after the systemic administration of sodium iodate (NaIO(3)). METHODS: Damage was produced in mice by injection of 15, 25, or 35 mg/kg NaIO(3). Visual function was assessed with the cued water maze (WM) behavioral test and the optokinetic reflex (OKR) measurement at different times after injection. Autofluorescence in whole eye flatmounts was quantified, and hematoxylin and eosin staining of paraffin sections was performed to assess changes in the outer retina. RESULTS: After 15 mg/kg NaIO(3), cued WM test results were normal, whereas OKR measurements were significantly decreased at all times. Focal RPE loss began on day 21, but no significant damage to the outer nuclear layer was observed. After 25 mg/kg NaIO(3), the cued WM test was transitionally reduced and the OKR measurement again decreased at all times. Large areas of RPE loss occurred on day 14 with a reduced outer nuclear layer on the same day. With 35 mg/kg NaIO(3), the cued WM test was reduced beginning on day 14 with complete obliteration of the OKR beginning on day 3, large areas of RPE loss on the same day, and a reduced outer nuclear layer on day 7. CONCLUSIONS: Stable, patchy RPE loss was observed with a low concentration of NaIO(3). The OKR measurement showed changes in visual function earlier than the cued WM test and before histologic findings were observed.

Long-term cellular and regional specificity of the photoreceptor toxin, iodoacetic acid (IAA), in the rabbit retina.

This study investigated the anatomical consequences of a photoreceptor toxin, iodoacetic acid (IAA), in the rabbit retina. Retinae were examined 2 weeks, 1, 3, and 6 months after systemic IAA injection. The retinae were processed using standard histological methods to assess the gross morphology and topographical distribution of damage, and by immunohistochemistry to examine specific cell populations in the retina. Degeneration was restricted to the photoreceptors and was most common in the ventral retina and visual streak. In damaged regions, the outer nuclear layer was reduced in thickness or eliminated entirely, with a concomitant loss of immunoreactivity for rhodopsin. However, the magnitude of the effect varied between animals with the same IAA dose and survival time, suggesting individual differences in the bioavailability of the toxin. In all eyes, the inner retina remained intact, as judged by the thickness of the inner nuclear layer, and by the pattern of immunoreactivity for protein kinase C-alpha (rod bipolar cells) and calbindin D-28 (horizontal cells). Müller cell stalks became immunoreactive for glial fibrillary acidic protein (GFAP) even in IAA-treated retinae that had no signs of cell loss, indicating a response of the retina to the toxin. However, no marked hypertrophy or proliferation of Müller cells was observed with either GFAP or vimentin immunohistochemistry. Thus the selective, long lasting damage to the photoreceptors produced by this toxin did not lead to a reorganization of the surviving cells, at least with survival as long as 6 months, in contrast to the remodeling of the inner retina that is observed in inherited retinal degenerations such as retinitis pigmentosa and retinal injuries such as retinal detachment.

An adaptive ERG technique to measure normal and altered dark adaptation in the mouse.

The time-course of dark adaptation provides valuable insights into the function and interactions between the rod and cone pathways in the retina. Here we describe a technique that uses the flash electroretinogram (ERG) response to probe the functional integrity of the cone and rod pathways during the dynamic process of dark adaptation in the mouse. Retinal sensitivity was estimated from the stimulus intensity required to maintain a 30 microV criterion b-wave response during a 40 min period of dark adaptation. When tracked in this manner, dark adaptation functions in WT mice depended upon the bleaching effects of initial background adaptation conditions. Altered dark adaptation functions, commensurate with the functional deficit were recorded in pigmented mice that lacked cone function (Gnat2 ( cplf3 )) and in WT mice injected with a toxin, sodium iodate (NaIO(3)), which targets the retinal pigment epithelium and also has downstream effects on photoreceptors. These data demonstrate that this adaptive tracking procedure measures retinal sensitivity and the contributions of the rod and/or cone pathways during dark adaptation in both WT control and mutant mice.

Conformational contagion in a protein: structural properties of a chameleon sequence.

Certain sequences, known as chameleon sequences, take both alpha- and beta-conformations in natural proteins. We demonstrate that a wild chameleon sequence fused to the C-terminal alpha-helix or beta-sheet in foreign stable proteins from hyperthermophiles forms the same conformation as the host secondary structure. However, no secondary structural formation is observed when the sequence is attached to the outside of the secondary structure. These results indicate that this sequence inherently possesses an ability to make either alpha- or beta-conformation, depending on the sequentially neighboring secondary structure if little other nonlocal interaction occurs. Thus, chameleon sequences take on a satellite state through contagion by the power of a secondary structure. We propose this "conformational contagion" as a new nonlocal determinant factor in protein structure and misfolding related to protein conformational diseases.

Application of thermo-setting gel as artificial vitreous.

PURPOSE: In this study, we produced a rabbit model and investigated the safety of intravitreous injection of a thermo-setting gel (TG) to determine whether TG can be used as artificial vitreous. METHODS: Ten male Japanese white rabbits were used. After performing vitrectomy in a unilateral eye, we injected 1 ml of WTG-127 into the vitreous cavity. The contralateral control eye was not given ophthalmic solution or surgery. Each eye was examined and intraocular pressure (IOP) and the electroretinogram (ERG) were evaluated. On day 28, all eyes were enucleated and examined. RESULTS: No abnormal findings and no elevation of IOP were observed. On the ERG, no significant difference in the latency and amplitude of either the a wave or b wave was observed. Histopathological examination of the retinal tissue showed no abnormalities. In the presence of a retinal tear, under the detached retina a drift of TG through the tear was observed in a few animals. CONCLUSIONS: In a rabbit model, the safety of using an intravitreous injection of thermo-setting gel as artificial vitreous was confirmed by ophthalmoscopic, electrophysiological, and histological studies for a relatively short observation period. However, TG injection cannot be expected to provide a tamponade effect.

Effects of intravitreal injection of tacrolimus (FK506) in experimental uveitis.

PURPOSE: To examine the immunosuppressive and neuroprotective effects of intravitreal injection of tacrolimus in experimental uveitis. METHODS: Tacrolimus (40 microg) was injected intravitreally in rabbits to examine safety. Experimental uveitis was induced in rabbits by systemic immunization with bovine serum albumin (BSA) followed by intravitreal challenge with BSA. On day 1 after BSA challenge, tacrolimus (20 or 40 microg) or betamethasone (400 microg) was injected intravitreally in one eye and balanced salt solution in the contralateral eye. The eyes were evaluated by slit-lamp biomicroscopy, electroretinography, and histopathology. RESULTS: No local or systemic adverse reaction was observed in normal rabbits. In experimental uveitis, intravitreal injection of tacrolimus significantly reduced intraocular inflammation in histopathological analysis (p < 0.03). Amplitudes on the electroretinogram were restored (p < 0.01), and retinal thickness was preserved in tacrolimus-treated eyes (p < 0.03). CONCLUSIONS: In experimental uveitis, intravitreal injection of tacrolimus effectively suppresses ocular inflammation and preserves retinal architecture.

Residual triamcinolone acetonide in the macular hole after vitrectomy.

PURPOSE: To report a case of vitrectomy using intraocular triamcinolone acetonide (TA), in which TA remained in the macular hole after surgery. DESIGN: Observational case report. METHODS: A 60-year-old Japanese man had a Stage II macular hole in the right eye with best-corrected visual acuity of 20/50. A pars plana vitrectomy using TA was performed. Visual acuity and anatomic results were followed up for a period of 8 weeks. RESULTS: On the sixth postoperative day, residual TA deposition was observed in the macular hole. On the 14th postoperative day, no residual TA was found and the macular hole was successfully closed. The best-corrected visual acuity of the right eye improved to 20/15. CONCLUSIONS: Residual TA in the macular hole after vitrectomy did not interfere with macular hole repair either anatomically or functionally.