A proof-of-principle for decontamination of transplantation kidney through UV-C exposition of the perfusate solution.

Kidney transplantation is a common yet highly demanding medical procedure worldwide, enhancing the quality of life for patients with chronic kidney disease. Despite its prevalence, the procedure faces a shortage of available organs, partly due to contamination by microorganisms, leading to significant organ disposal. This study proposes utilizing photonic techniques associated with organ support machines to prevent patient contamination during kidney transplantation. We implemented a decontamination system using ultraviolet-C (UV-C) irradiation on the preservation solution circulating through pigs' kidneys between harvest and implant. UV-C irradiation, alone or combined with ultrasound (US) and Ps80 detergent during ex-vivo swine organ perfusion in a Lifeport® Kidney Transporter machine, aimed to reduce microbiological load in both fluid and organ. Results show rapid fluid decontamination compared to microorganism release from the organ, with notable retention. By including Ps80 detergent at 0.5% during UV-C irradiation 3 log10 (CFU mL-1) of Staphylococcus aureus bacteria previously retained in the organ were successfully removed, indicating the technique's feasibility and effectiveness.

In vitro evaluation of the cis-[Ru(phen)2(pPDIp)]2+⁎⁎ complex for antimicrobial photodynamic therapy against Sporothrix brasiliensis and Candida albicans.

BACKGROUND: Photodynamic therapy (PDT) activates a photosensitizer by visible light to generate cytotoxic oxygen species that lead to cell death. With proper illumination, PDT is often used in applications on superficial and sub-surface lesions. Sporotrichosis infection occurs by Sporothrix fungi which causes a skin wound, worsened by Candida albicans infections. This study investigated the photosensitizing efficiency of the Ru(phen)2(pPDIp)(PF6)2 complex, RupPDIp, against S. brasiliensis and C. albicans. MATERIAL AND METHODS: RupPDIp efficiency against these fungi was tested using 450 nm (blue light and 36 J/cm2) and 525 nm (green light, 25.2 J/cm2) at 0.05-20 µM concentrations. To ensure PDT effectiveness, control groups were tested in the absence and in the presence of RupPDIp under light irradiation and in the dark. RESULTS: RupPDIp eliminated both fungi at ≤5.0 µM. Green light showed the best results, eliminating S. brasiliensis and C. albicans colonies at RupPDIp 0.5 µM and 0.05 µM, respectively. CONCLUSION: RupPDIp is a promising photosensitizer in aPDT, eliminating 106 CFU/mL of both fungi at 450 nm and 525 nm, with lower light doses and concentrations when treated with the green light compared to the blue light.

Clinical study of anogenital condyloma acuminata treatment with photodynamic therapy including immunocompromised conditions.

Human Papillomavirus (HPV) infection is highly prevalent worldwide, and one of its consequences is the external genital wart, or Condyloma Acuminata (CA). The present study used Photodynamic Therapy (PDT) to treat CA lesions. PDT treated 23 patients with a clinical diagnosis of multifocal and unifocal CA. Patients were divided into Group 1 (G1, Patients without pathologies associated with immunodeficiency) and Group 2 (G2, patients with pathologies associated with immunodeficiency). In the G1 group (19 patients), PDT resulted in a Complete Response in 68.4% (average 5 PDT cycles), Partial Response in 26.3% (average 10 PDT cycles), and No Response in 5.3% (average 6 PDT cycles). In the G2 group (4 patients), 100% of subjects showed a partial response (8 PDT cycles). These patients in the G2 and with partial response had associated pathologies, such as renal failure, breast cancer, and HIV. There was a slight decrease in lesions (20-40%) post-treatment in these cases. Four months after treatment, no new lesions or recurrence were observed in the entire area treated with PDT using low doses of PDT. Eighty-six percent of the patients tolerated the treatments well. We conclude that PDT is a promising and safe treatment for CA lesions compared to traditional treatments.

Photonic effects in natural nanostructures on Morpho cypris and Greta oto butterfly wings.

Photonic crystals are some of the more spectacular realizations that periodic arrays can change the behavior of electromagnetic waves. In nature, so-called structural colors appear in insects and even plants. Some species create beautiful color patterns as part of biological behavior such as reproduction or defense mechanisms as a form of biomimetics. The interaction between light and matter occurs at the surface, producing diffraction, interference and reflectance, and light transmission is possible under suitable conditions. In particular, there are two Colombian butterflies, Morpho cypris and Greta oto, that exhibit iridescence phenomena on their wings, and in this work, we relate these phenomena to the photonic effect. The experimental and theoretical approaches of the optical response visible region were studied to understand the underlying mechanism behind the light-matter interaction on the wings of these Colombian butterflies. Our results can guide the design of novel devices that use iridescence as angular filters or even for cosmetic purposes.

Norovirus recovery from floors and air after various decontamination protocols.

BACKGROUND: The dispersal of airborne norovirus (NoV) particles from the floor after contamination with faeces or vomit is a challenge for infection control, as this pathogen is infectious at low doses. Therefore, it is imperative to establish a safe protocol for floor decontamination. AIM: To assess the presence of residual NoV-GII particles on floors and airborne particles following various floor decontamination procedures. METHODS: Two types of floor (vinyl and granite) were contaminated intentionally with 10% human faeces, positive for NoV-GII. Two decontamination protocols were implemented: cleaning followed by disinfection using 1% sodium hypochlorite, and cleaning followed by disinfection using a manual ultraviolet C (UV-C) light device. Swab samples were taken from the floors, and air samples were obtained using an air sampler. The TaqMan method for real-time reverse transcription-quantitative polymerase chain reaction was employed for analysis. FINDINGS: The disinfection protocol using 1% sodium hypochlorite after cleaning proved to be more effective than cleaning followed by UV-C light exposure (P<0.001). Viral particles were detected in 27 of 36 air samples after cleaning, with no significant difference between the two floor types. On average, 617 genome copies/sample were identified in air samples after cleaning, but the number decreased gradually after disinfection. CONCLUSION: NoV-GII can be aerosolized during floor cleaning, and its particles may be inhaled and then swallowed or can settle on surfaces. Therefore, residual viral particles on floors must be fully eliminated. Cleaning followed by 10 min of 1% sodium hypochlorite disinfection proved to be the superior decontamination protocol.

Calreticulin mutant mice develop essential thrombocythemia that is ameliorated by the JAK inhibitor ruxolitinib.

Mutations of calreticulin (CALR) are detected in 25-30% of patients with essential thrombocythemia (ET) or primary myelofibrosis and cause frameshifts that result in proteins with a novel C-terminal. We demonstrate that CALR mutations activated signal transducer and activator of transcription 5 (STAT5) in 293T cells in the presence of thrombopoietin receptor (MPL). Human megakaryocytic CMK11-5 cells and erythroleukemic F-36P-MPL cells with knocked-in CALR mutations showed increased growth and acquisition of cytokine-independent growth, respectively, accompanied by STAT5 phosphorylation. Transgenic mice expressing a human CALR mutation with a 52 bp deletion (CALRdel52-transgenic mice (TG)) developed ET, with an increase in platelet count, but not hemoglobin level or white blood cell count, in association with an increase in bone marrow (BM) mature megakaryocytes. CALRdel52 BM cells did not drive away wild-type (WT) BM cells in in vivo competitive serial transplantation assays, suggesting that the self-renewal capacity of CALRdel52 hematopoietic stem cells (HSCs) was comparable to that of WT HSCs. Therapy with the Janus kinase (JAK) inhibitor ruxolitinib ameliorated the thrombocytosis in TG mice and attenuated the increase in number of BM megakaryocytes and HSCs. Taken together, our study provides a model showing that the C-terminal of mutant CALR activated JAK-STAT signaling specifically downstream of MPL and may have a central role in CALR-induced myeloproliferative neoplasms.

Severe Staphylococcus lugdunensis keratitis.

We report a severe case of Staphylococcus lugdunensis (S. lugdunensis) keratitis presenting as suppurative keratitis in a 77-year-old woman. The patient's chief complaint was eye pain and decreased visual acuity in her right eye. Suppurative keratitis with a severe corneal abscess was diagnosed by a slit-lamp ophthalmic examination. The causative organism was identified as S. lugdunensis by bacterial culture, using a corneal abrasion specimen. She was treated with an intravenous drip infusion of ceftazidime and instillation of gentamicin sulfate ophthalmic solution (six times daily) and ofloxacin ophthalmic ointment (once daily before bedtime) as empiric therapy. Her hospital course was complicated by a corneal perforation of her right eye. The antibiotic susceptibility for S. lugdunensis was sensitive, but with a slightly high MIC for antibiotics used in empiric therapy. The therapeutic drug was changed to levofloxacin ophthalmic solution. The corneal abscess left a scar after healing. Representative causative organisms of suppurative keratitis include Pseudomonas aeruginosa and Streptococcus pneumoniae, but care must be taken in cases involving rare causative organisms. Empiric therapy is necessary for rapidly progressing suppurative keratitis, but a detailed examination of the causative organism is important for therapeutic planning before empiric therapy.

Molecular-scale surface structures of oligo(ethylene glycol)-terminated self-assembled monolayers investigated by frequency modulation atomic force microscopy in aqueous solution.

The structure and protein resistance of oligo(ethylene glycol)-terminated self-assembled monolayers (OEG-SAMs) have been studied intensively using various techniques. However, their molecular-scale surface structures have not been well understood. In this study, we performed molecular-resolution imaging of OH-terminated SAMs (OH-SAMs) and hexa(ethylene glycol) SAMs (EG(6)OH-SAMs) formed on a Au(111) surface in an aqueous solution by frequency modulation atomic force microscopy (FM-AFM). The results show that most of the ethylene glycol (EG) chains in an EG(6)OH-SAM are closely packed and well-ordered to present a molecularly flat surface even in an aqueous solution. In addition, we found that EG(6)OH-SAMs have nanoscale defects, where molecules take a disordered arrangement with their molecular axes parallel to the substrate surface. We also found that the domain size (50-200 nm) of an EG(6)OH-SAM is much larger than that of OH-SAMs (10-40 nm). These findings should significantly advance molecular-scale understanding about the surface structure of OEG-SAMs.

Quantitative autistic traits ascertained in a national survey of 22 529 Japanese schoolchildren.

OBJECTIVE: Recent epidemiologic studies worldwide have documented a rise in prevalence rates for autism spectrum disorders (ASD). Broadening of diagnostic criteria for ASD may be a major contributor to the rise in prevalence, particularly if superimposed on an underlying continuous distribution of autistic traits. This study sought to determine the nature of the population distribution of autistic traits using a quantitative trait measure in a large national population sample of children. METHOD: The Japanese version of the Social Responsiveness Scale (SRS) was completed by parents on a nationally representative sample of 22 529 children, age 6-15. RESULTS: Social Responsiveness Scale scores exhibited a skewed normal distribution in the Japanese population with a single-factor structure and no significant relation to IQ within the normal intellectual range. There was no evidence of a natural 'cutoff' that would differentiate populations of categorically affected children from unaffected children. CONCLUSION: This study provides evidence of the continuous nature of autistic symptoms measured by the SRS, a validated quantitative trait measure. The findings reveal how paradigms for diagnosis that rest on arbitrarily imposed categorical cutoffs can result in substantial variation in prevalence estimation, especially when measurements used for case assignment are not standardized for a given population.

Mechanism of Trypanosoma cruzi death induced by Cratylia mollis seed lectin.

Incubation of T. cruzi epimastigotes with the lectin Cramoll 1,4 in Ca(2+) containing medium led to agglutination and inhibition of cell proliferation. The lectin (50 microg/ml) induced plasma membrane permeabilization followed by Ca(2+) influx and mitochondrial Ca(2+) accumulation, a result that resembles the classical effect of digitonin. Cramoll 1,4 stimulated (five-fold) mitochondrial reactive oxygen species (ROS) production, significantly decreased the electrical mitochondrial membrane potential (Delta Psi(m)) and impaired ADP phosphorylation. The rate of uncoupled respiration in epimastigotes was not affected by Cramoll 1,4 plus Ca(2+) treatment, but oligomycin-induced resting respiration was 65% higher in treated cells than in controls. Experiments using T. cruzi mitochondrial fractions showed that, in contrast to digitonin, the lectin significantly decreased Delta Psi(m) by a mechanism sensitive to EGTA. In agreement with the results showing plasma membrane permeabilization and impairment of oxidative phosphorylation by the lectin, fluorescence microscopy experiments using propidium iodide revealed that Cramoll 1,4 induced epimastigotes death by necrosis.

Uncoupling and oxidative stress in liver mitochondria isolated from rats with acute iron overload.

One hypothesis for the etiology of cell damage arising from iron overload is that its excess selectively affects mitochondria. Here we tested the effects of acute iron overload on liver mitochondria isolated from rats subjected to a single dose of i.p. 500 mg/kg iron-dextran. The treatment increased the levels of iron in mitochondria (from 21 +/- 4 to 130 +/- 7 nmol/mg protein) and caused both lipid peroxidation and glutathione oxidation. The mitochondria of iron-treated rats showed lower respiratory control ratio in association with higher resting respiration. The mitochondrial uncoupling elicited by iron-treatment did not affect the phosphorylation efficiency or the ATP levels, suggesting that uncoupling is a mitochondrial protective mechanism against acute iron overload. Therefore, the reactive oxygen species (ROS)/H+ leak couple, functioning as a mitochondrial redox homeostatic mechanism could play a protective role in the acutely iron-loaded mitochondria.

[Histological study of the effect of conjunctival transplantation on rabbit cornea with alkali burned].

PURPOSE: A histopathological study to investigate the efficacy of conjunctival auto-transplantation on alkaline chemical burns of the ocular surface. MATERIAL AND METHODS: An alkaline chemical burn model was developed in one eye of rabbits using 0.1 N NaOH solution. In one group conjunctival transplantation was performed. A control group did not receive conjunctival transplantation. A histological follow-up study was performed by light microscopy with hematoxylin eosin stain and periodic acid Schiff staining by fluoro-microscopy using epithelial Keratin-AE 5 antibody, and by transmission electron microscopy(TEM). RESULTS: The transplanted group showed scar formation between the transplanted conjunctival tissue and the sclera. At 20 days and 8 weeks after the transplantation, neovascularization and cell infiltration in the subepithelium of the limbus was decreased compared with the transplanted group at 10 days. The control group showed a decrease of cell infiltration in the limbal area compared with the group at 10 days, but conjunctival tissue with thick collagenous tissue and neovascularization instead of scar tissue developed on the injured cornea. AE 5 positive cells were not found in the limbus in either group. In the transplanted group, in TEM, the basement membrane of transplanted conjunctiva showed less irregularity, and degenerated fibroblasts were present at the margin of the scar tissue. In the control group, the basement membrane of the conjunctiva showed an irregular pattern and fibroblasts beneath the conjunctival epithelium had large nuclei. CONCLUSION: In the transplanted group, scar tissue developed and suppressed cell infiltration, neovascularization, and conjunctival tissue in the injured cornea and secured re-structuring of the limbal tissue.

Phosphorylation of a bifunctional enzyme, 6-phosphofructo-2-kinase/fructose-2,6-bisphosphate 2-phosphatase, is regulated physiologically and developmentally in rosette leaves of Arabidopsis thaliana.

The phosphorylation status of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphate 2-phosphatase (EC 2.7.1.105/ EC 3.1.3.46) in rosette leaves of Arabidopsis was examined. Immunoblotting with specific antisera detected 96-kDa and 92-kDa bands in the crude protein extracts from rosette leaves of Arabidopsis. Incubation of protein samples with alkaline phosphatase before SDS-PAGE reduced the 96-kDa band with concomitant increase of the 92-kDa band, suggesting that the former is a phosphorylated form of the latter. In accordance with this result, 96-kDa and 92-kDa bands were immuno-precipitated from the crude protein extracts from [(32)P]orthophosphate-labeled rosettes of Arabidopsis; and, the former was heavily labeled, the latter faintly labeled. Analysis of phospho-amino acid residues derived from the [(32)P]-labeled 96-kDa band revealed that the phosphorylation occurred on serine and threonine residues, excluding the possibility that the phosphorylated band represent a phospho-histidine intermediate that is known to form in the phosphatase reaction. The relative level of the 96-kDa band over the 92-kDa band in whole rosette extracts changed diurnally and was highest at the beginning of nighttime. Furthermore, the 96-kDa band was highly enriched in the extracts of very young rosette leaves, suggesting that the phosphorylation status of 6-phosphofructo-2-kinase/fructose-2,6-bisphosphate 2-phosphatase is regulated physiologically and developmentally in Arabidopsis.

Immunosuppressive effect of cholera toxin B on allergic conjunctivitis model in guinea pig.

PURPOSE: To investigate the new method of immunotherapy using cholera toxin B (CTB) in experimental allergic conjunctivitis. METHODS: We used 21 white Hartley guinea pigs. The animals were sensitized by intraperitoneal injection of ovalbumin (100 microg/mL) and albumin hydroxide (5 mg/mL) repeated after an interval of 2 weeks. One week after the second injection, conjunctivitis was induced by topical instillation of ovalbumin (5 mg/mL). The animals were divided into two groups, CTB group and control group. The CTB group underwent pretreatment of topical instillation of CTB (4 microg/30 mL) and ovalbumin (10 microg/30 mL), three times a day for 3 days, 1 week before the intraperitoneal injection. The control group did not undergo the pretreatment. Clinical examination was performed at 0.5, 6, and 24 hours after the development of conjunctivitis. Histological examination was performed at 6 and 24 hours. RESULTS: Both groups developed palpebral and bulbar edema with hyperemia 30 minutes after instillation of ovalbumin. The allergic reaction score was significantly less in the CTB group than in the control group (Mann-Whitney U-test: P <.01). The clinical reactions subsided after 6 hours. The CTB group showed less eosinophilic infiltration in the conjunctiva and the limbus, particularly in the conjunctival epithelium, than the control group at 6 and 24 hours. CONCLUSION: Pretreatment with topical CTB and antigen suppresses clinical and histological findings in experimentally induced allergic conjunctivitis.

Immunosuppressive effect of cholera toxin B on allergic conjunctivitis model in the guinea Pig

Purpose: To investigate the immunosuppressive effects of mucosal immune therapy in experimental allergic conjunctivitis.Method: We used 11 white Hartrey guinea pigs divided into two groups. Six animals (treated group) received pretreatment with topical instillation of cholera toxin B (4 &mgr;g/30 ml) and ovalbumin (10 &mgr;g/30 ml). The other group of 5 animals served as control. All the animals received intra-abdominal injection of ovalbumin (100 g/mL) and aluminum hydroxide (5 mg/mL) repeated twice 2 weeks apart. Allergic conjunctivitis was induced by topical instillation of ovalbumin solution (5 mg/mL) 1 week after the above procedure. Result: Both groups developed palpebral and bulbar edema with hyperemia 30 minutes after instillation. The allergic reaction was significantly less in score in the treated than in the control group (Mann-Whitney U-test: P <.01). The clinical findings subsided after 6 hours. The treated group showed less eosinophilic infiltration in the conjunctiva and the limbus, particularly in the conjunctival epithelium, than in the control group at 6 and 24 hours.Conclusion: Pretreatment with topical cholera toxin B and antigen suppresses clinical and histological findings in experimentally induced allergic conjunctivitis.

[Immunohistochemical study of interstitial keratitis in an animal model].

PURPOSE: We performed an immunohistochemical study on the development of interstitial keratitis in a rabbit model sensitized by ovalbumin (OA). METHODS: A mixture of OA (5 micrograms/ml) and Freund's complete adjuvant was initially injected subcutaneously (0.4 ml) into the rabbits' back and footpad (0.2 ml). After a week, the rabbits were sensitized by an injection of the same solution into the back (0.5 ml) again. After 4 weeks the rabbits underwent the same treatment as a booster shot. Then a week later OA solution (0.05 ml) was injected into the corneal stroma. We observed the cornea on days 1-3, 7, and 10 after the corneal treatment. Corneas on days 3 and 10 were examined by immunohistological methods using hematoxylin-eosin stain, methylgreen pyronin stain, and by immunohistochemical methods with anti-CD 4, anti-CD 8, and anti-OA antibodies. The localization of specific antibodies was identified by fluorescent-antigen method. Electron-microscopic observation was also done. RESULTS: Rabbits developed corneal opacity and edema on day 1, corneas had on immune ring with a peak intensity on day 3, and vascularization on day 7 after corneal treatment. Microscopic examination revealed infiltration of neutrophils in to the area of the immune ring on day 3 and many plasma cells at the limbus and stroma on day 10. CD 4 positive cells were found at the limbus and stroma on days 3 and 10. CD 8 positive cells were found at the limbus and stroma only on day 10. OA positive findings were observed at the immune ring and its inner area. In the fluorescent-antigen method, specific antibodies were found in plasma cells at the limbus on days 3 and 10. CONCLUSIONS: In our experimental model of interstitial keratitis with immune ring and vascularization, the Arthus reaction was dominant. Infiltration of antigen specific plasma cells in the stroma with vascularization caused a modification of pathologic reaction in keratitis.

Comparative study of effects of impact tone and steady state tone exposure: EP and concentration of K+ ion and Na+ ion.

To test the adequacy of equal energy principle (EEP), guinea pigs were exposed to impact tone. The changes in electrophysiological data, namely endocochlear potential (EP) and the change in K+ ion and Na+ ion concentrations in the endolymph were investigated. The frequency of impact tone was 1 pulse/second or 1 pulse/3 seconds. The steady state tone had Leq24h = 100, 95, 90 or 85 dB, and impact tone had Leq24h = 95, 90 or 85 dB. The results are the following. Both steady state and impact tone exposure cause changes of electrophysiological data. The effects on the absolute value of negative EP induced by impact tone exposures were smaller than that of steady state tone of the same Leq. The rate of pulses was also an important factor for impact tone exposure. Impact tone exposure of 1 pulse/second caused smaller absolute value of negative EP than that of 1 pulse/3 seconds. The K+ ion concentration time course in the endolymph remained similar to the control (Exp. 1) only in Exp. 8 (85 dB; the lowest steady state noise exposure in our experiments), but no decrease in the K+ ion concentration was detected in the other experiments, suggesting an alteration in the K+ ion flow. The Na+ ion concentration time course was also influenced showing no increase in Na+ ion concentration compared to the control (Exp. 1c) and the lowest steady-state exposure experiment (Exp. 8c). Our experimental results suggest that both the K+ ion and Na+ ion movement are altered by tone exposure. We found also that the different types of noise exposure with the same Leq value does not exhibit the same changes. Leq24h is not an accurate damage risk criteria.

[Immunosuppressive effect of cholera toxin B on allergic conjunctivitis model in the guinea pig].

PURPOSE: To investigate the immunosuppressive effects of mucosal immune therapy in experimental allergic conjunctivitis. METHOD: We used 11 white Hartrey guinea pigs divided into two groups. Six animals (treated group) received pretreatment with topical instillation of cholera toxin B (4 micrograms/30 ml) and ovalbumin (10 micrograms/30 ml). The other group of 5 animals served as control. All the animals received intraabdominal injection of ovalbumin (100 g/ml) and aluminium hydroxide (5 mg/ml) repeated twice 2 weeks apart. Allergic conjunctivitis was induced by topical instillation of ovalbumin solution (5 mg/ml) one week after the above procedure. RESULT: Both groups developed palpebral and bulbar edema with hyperemia 30 minutes after instillation. The allergic reaction was significantly less in score in the treated than in control group (Mann Whitney U-test: p < 0.01). The clinical findings subsiced after 6 hours. The treated group showed less eosinophilic infiltration in the conjunctiva and the limbus, particularly in the conjunctival and the limbus, particularly in the conjunctival epithelium, than in control group at 6 and 24 hours. CONCLUSION: Pretreatment with topical cholera toxin B and antigen suppresses clinical and histological findings in experimentally induced allergic conjunctivitis.

The effects of tone exposure on the inner ear functions in the guinea pig: impact tone vs. steady state tone.

The damage-risk criterion (DRC) for hearing supposes that sound exposure with equal energy implies equal risk for noise-induced hearing loss (NIHL). We measured cochlear microphonics (CM), compound action potential (CAP), endocochlear potential (EP) and K+ ion concentration in the scala media, to see if the same level of Leq24h (impact tone and steady state tone) induced the same physiological changes in the inner ear function or not. Regarding the equal energy principle (EEP), we also examined if the EEP is appropriate or not at exposure of moderate level tone. We also checked how the time interval between impact tones affects or not the inner ear functions at the same Leq24h tone exposure. Therefore we used exposure at 1 pulse/second or 1 pulse/3 seconds and steady state tone exposure at Leq24h=90, 85 and 80 dB. The results are the following. Both steady state and impact tone exposure causes change of the electrophysiological data. First, CM maximum output voltage after exposure to impact tone of 115 dB (Leq24h=90 dB) was lower than after exposure to a 8 kHz steady state tone of 90 dB. CAP threshold (below 10 microV) obtained after the 115 and 110 dB exposure of impact tone were 5-10 dB higher than that of steady state tone of 90 dB. The negative EP induced by impact tone exposures showed the same tendency as the CM experiments. Having more frequent pulses (1 pulse/second vs. to 1 pulse/3 seconds) showed more inhibition. The K+ concentration time course remained similar to the control when the Leq24h was low (80 dB). Impact tone exposure induced stronger effects to the inner ear at exposure of moderate level tone than that of steady state tone of Leq24h.