Roles of NADPH oxidases in cisplatin-induced reactive oxygen species generation and ototoxicity.

In our previous study, we clearly demonstrated the roles of pro-inflammatory cytokines, including tumor necrosis factor-alpha, interleukin-1beta (IL-1beta), and IL-6, and subsequent reactive oxygen species (ROS) generation on the pathogenesis of cisplatin ototoxicity in vitro and in vivo. ROS generation in cisplatin-treated HEI-OC1 auditory cells was also correlated with changing mitochondrial membrane potential. However, the roles of NADPH oxidase in cisplatin-induced ROS generation and ototoxicity have not been fully elucidated. Herein, immunohistochemical studies demonstrated that treatment of cisplatin induced the expression of NADPH oxidase isoforms NOX-1 and NOX-4 in HEI-OC1 auditory cells. Expression of mRNA for NOX-1, NOX-4, NOXO1, NOXA1, p47(phox), and p67(phox) was also increased. Inhibition of NADPH oxidase with diphenyleniodonium chloride or apocynin abolished ROS production and the subsequent apoptotic cell death in cisplatin-treated cells. Furthermore, suppression of NOX1 and NOX4 expression by small interfering RNA transfection markedly abolished the cytotoxicity and ROS generation by cisplatin. Together, our data suggest that ROS generated, in part, through the activation of NADPH oxidase plays an essential role in cisplatin ototoxicity.

Generation of attosecond x-ray and gamma-ray via Compton backscattering.

The generation of an isolated attosecond gamma-ray pulse utilizing Compton backscattering of a relativistic electron bunch has been investigated. The energy of the electron bunch is modulated while the electron bunch interacts with a co-propagating few-cycle CEP (carrier envelope phase)-locked laser in a single-period wiggler. The energy-modulated electron bunch interacts with a counter-propagating driver laser, producing Compton back-scattered radiation. The energy modulation of the electron bunch is duplicated to the temporal modulation of the photon energy of Compton back-scattered radiation. The spectral filtering using a crystal spectrometer allows one to obtain an isolated attosecond gamma-ray.

Induction of myeloma-specific cytotoxic T lymphocytes ex vivo by CD40-activated B cells loaded with myeloma tumor antigens.

We investigated to establish CD40-activated B cells (CD40-B cells) as alternative antigen-presenting cells (APCs) for the induction of myeloma-specific cytotoxic T lymphocytes (CTLs). To generate CD40-B cells, peripheral blood mononuclear cells were co-cultured with CD40L-transfected J558 cells in the presence of IL-4, insulin, transferrin, and cyclosporine for 14 days, and pulsed with myeloma lysates. The CD40-B cells consistently expressed high levels of CD80, CD86, CD54, CCR7, and HLA-DR. The CD40-B cells produced IL-12, IFN-gamma, and IL-6 during the culture period, but not IL-10. In addition, the CD40-B cells showed potent allogeneic T-cell stimulatory capacities that depended on the dose ratio and had the potential to polarize naïve T cells into Th1 subsets. The CD40-B cells loaded with tumor lysates induced strong target-specific CTLs, based on large numbers of IFN-gamma secreting cells and higher cytotoxic activity against target cells compared to the CD40-B cells without the tumor lysates. These results suggest that CD40-B cells loaded with myeloma lysates might provide alternative APCs for cellular immunotherapy in patients with myeloma.

Fabrication of silicon oxide nanowires embedded with Au nanoparticle or Au nanowire: its use as template to hollow silica nanotube.

Silicon oxide nanowires which contains Au nanoparticles or an Au nanowire were fabricated by thermal evaporation chemical vapor deposition method using Au as catalyst. Silicon oxide wafers were used as the collector. The diameters of silicon oxide nanowires range from 20 to 150 nm. The larger the diameter of Si nanowire is, the larger the diameter of embedded Au nanoparticles. The separation between Au nanoparticles increases with the diameter. Different forms of silicon oxide nanowires were observed at different growth temperature: silicon oxide nanowires embedded with Au-containing nanoparticles at 1250 degrees C and Au/silicon oxide coaxial nanocable at 1425 degrees C. Using KCN solution, the nanoparticles or the nanocable inside silicon oxide nanowires were extracted, leaving hollow silicon oxide nanotubes.

Colon perforation due to embolization coil for internal iliac aneurysm.

Coil migration is an extremely rare but hazardous complication of aneurysmal coil embolization. Only 1 case report has described coil migration following endovascular exclusion to gastrointestinal (GI) tract. We report the experience of a case of colon penetration caused by embolization coil placed for internal iliac aneurysm. A 66-year-old man visited the Emergency Department for hematochezia that had persisted for 3 months. Stent insertion and coil embolization of left internal iliac artery aneurysm had been performed on the patient 18 months ago. Colonoscopy was performed. It suggested penetration of sigmoid colon by embolization coil and diverticulum. Angiography revealed extravasation of contrast media at left internal iliac artery. Covered stent deployment was done in the left internal iliac artery. One week after the stent insertion, the patient underwent anterior resection, aneurysm resection, and coil removal. The patient recovered without complications. He was discharged at 2 weeks after the operation.

Vascular Complications Related to Posterior Lumbar Disc Surgery.

PURPOSE: To evaluate patients who underwent surgical or endovascular treatment after vascular injury related to posterior lumbar disc surgery. MATERIALS AND METHODS: We retrospectively reviewed seven cases of vascular injuries (four lacerations, one arteriovenous fistula [AVF], and two pseudoaneurysms) related to lumbar disc surgery by a posterior approach from January 1997 to December 2016 at Chonnam National University Hospital. Information of patient characteristics, diagnosis, treatment strategies, and outcomes were analyzed. RESULTS: Five out of seven cases were inhospital cases. In three laceration cases, each patient instantly became hypotensive and a life-threatening arterial injury was suspected. Therefore, the patient was immediately turned to the supine position and surgical repair was performed. The patients with pseudoaneurysm and AVF were treated by endovascular intervention. Remaining two were referred cases under the impression of vascular injuries. One laceration case of them was in preshock condition, and the left common iliac artery was surgically repaired. The other referred patient showed pseudoaneurysm which was treated with stent graft insertion. There was no surgery or endovascular intervention related death and none of the patients suffered any sequela related to vascular injury. CONCLUSION: Vascular injury associated with posterior lumbar disc surgery is not common, but can be fatal. Early recognition, diagnosis, and prompt treatment are essential to prevent fatal outcomes. Recently, endovascular intervention is increasingly and preferably used because of its low morbidity and mortality. However surgery is still the best option for the patients with unstable vital sign and endovascular approach can be applied to stable patients.

Heme oxygenase-1 attenuates the cisplatin-induced apoptosis of auditory cells via down-regulation of reactive oxygen species generation.

Heme oxygenase-1 (HO-1), the rate-limiting enzyme of heme catabolism, is known to modulate various cellular functions, including cytokine production, cell proliferation, and apoptosis, in stress-related conditions. However, the role of HO-1 in the auditory system remains elusive. Herein, we demonstrate that pharmacologic induction of HO-1 along with catalytic activation significantly suppressed apoptosis of HEI-OC1 cells induced by cisplatin. Studies of ectopic expression of pcDNA3-HO-1 and siRNA of HO-1 further revealed the protective role of HO-1 against cisplatin in HEI-OC1 cells. Among the catabolic metabolites of HO-1, both carbon monoxide (CO) and bilirubin were directly involved in the protective role of HO-1 against cisplatin through inhibition of reactive oxygen species generation. Furthermore, pharmacological induction of HO-1 completely prevented the destruction of outer hair cell arrays by cisplatin through a CO-dependent mechanism in organotrophic culture of the rat primary organ of Corti explants. These results suggest that HO-1 may serve as a safeguard of auditory sensory hair cells against a variety of challenges of oxidative stress, including noise trauma, presbycusis, and ototoxic drugs, respectively.

Transarterial embolization for postoperative hemorrhage after abdominal surgery.

The study goal was to evaluate the efficacy, safety, and clinical outcome of transarterial embolization for postoperative hemorrhage after abdominal surgery. Thirty-three patients were referred for angiography because of gastrointestinal or intra-abdominal bleeding after abdominal surgery. Urgent angiography and transarterial embolization was performed in all 33 patients. The clinical and angiographic features were retrospectively reviewed. Angiography revealed a discrete bleeding focus in 26 (79%) of 33 patients. Transarterial embolization was technically successful in 24 (92%) of 26 patients with a discrete bleeding focus. Rebleeding occurred in four (17%) of 24 patients. They were successfully managed with repeat embolization. There was no procedure-related complication during follow-up period. Angiography has a high detection rate of bleeding site in patients with postoperative hemorrhage after abdominal surgery. Transarterial embolization is considered to be an effective and safe means in the management of postoperative hemorrhage.

Transretroperitoneal CT-guided embolization of growing internal iliac artery aneurysm after repair of abdominal aortic aneurysm: a transretroperitoneal approach with intramuscular lidocaine injection technique.

This study was designed to evaluate the efficacy and safety of CT-guided embolization of internal iliac artery aneurysm (IIAA) after repair of abdominal aortic aneurysm by transretroperitoneal approach using the lidocaine injection technique to iliacus muscle, making window for safe needle path for three patients for whom CT-guided embolization of IIAA was performed by transretroperitoneal approach with intramuscular lidocaine injection technique. Transretroperitoneal access to the IIAA was successful in all three patients. In all three patients, the IIAA was first embolized using microcoils. The aneurysmal sac was then embolized with glue and coils without complication. With a mean follow-up of 7 months, the volume of the IIAAs remained stable without residual endoleaks. Transretroperitoneal CT-guided embolization of IIAA using intramuscular lidocaine injection technique is effective, safe, and results in good outcome.

To achieve national self-sufficiency: recent progresses in deceased donation in Korea.

BACKGROUND: The disparity between patients awaiting transplantation and available organs has widened, and resultant organ shortage became a world crisis. The transplantation community has made considerable progress in national organ donation system in Korea, and significant growth in the number of deceased donors has been witnessed. METHODS: After introduction of the Organ Transplant Act, which was enacted in 2000, transparency was established in organ allocation system in Korea. However, the number of deceased donor dwindled significantly from 162 in 1999 to 36 in 2002. To improve deceased donation, several strategies were pursued, and finally new national organ donation system was established through the amendment of the Organ Transplant Act. RESULTS: Organ incentive system, which was introduced in 2003, failed to increase the number of deceased donors (68 in 2003, 86 in 2004, and 91 in 2005). Monetary incentive to the bereaved family was introduced in 2006 and slightly increased the number of deceased donor (141 in 2006). However, this effect was not long-lasting (148 in 2007). After enforcement of the new Organ Transplant Act, which included nationwide independent organ procurement organization and mandatory report of potential brain death, the number of deceased donors significantly increased, reaching 368 in 2011. The growth continued and the number of deceased donors reached 409 (8.03 pmp) in 2012. CONCLUSION: There has been a significant growth in the number of deceased donors in Korea since the appropriate deceased organ donation system was launched. A comprehensive national program is required to improve deceased donation and achieve self-sufficiency.

Benzo(a)pyrene-induced apoptotic death of mouse hepatoma Hepa1c1c7 cells via activation of intrinsic caspase cascade and mitochondrial dysfunction.

Benzo(a)pyrene (BaP), a potent carcinogen, has been shown to induce apoptosis via activation of caspase-3. However, the upstream of caspase-3 and other apoptosis signaling remain to be elusive. Herein, we demonstrated that treatment of Hepa1c1c7 cells with BaP increased the transcriptional expression of aryl hydrocarbon nuclear transporter and cytochrome p450 1A1 in a time and dose-dependent manner but did not aromatic hydrocarbon receptor. Also, the catalytic activation of caspase-3 and caspase-9 was induced whereas that of caspase-3 and caspase-9 was not by the addition of BaP. BaP also induced the mitochondrial dysfunction, including transition of mitochondria membrane potential and cytosolic release of cytochrome c. Furthermore, a decrease in the expression of Bcl-2 to Bax ratio and phosphorylation of p53(Ser 15) were observed in BaP-treated cells. Taken together, these results demonstrated that BaP-induced apoptosis of Hepa1c1c7 cells via activation of intrinsic caspase pathway including caspase-3, caspase-9, with mitochondrial dysfunction and p53 activation.

Involvement of hydrogen peroxide in mistletoe lectin-II-induced apoptosis of myeloleukemic U937 cells.

Mistletoe lectin-II, a major component of Korean mistletoe (Viscum album var. coloratum) induces apoptotic death in cancer cells. In this study, we demonstrated that lectin-II induced the generation of pro-oxidants and thus resulted in the apoptotic death of human myeloleukemic U937 cells. We observed that lectin-II-induced apoptotic death was inhibited by antioxidants including reduced glutathione (GSH), N-acetylcysteine (NAC), ebselen, mnTBP, catalase and pyrrolidine dithiocarbamate (PDTC). GSH and NAC also abolished the apoptotic DNA ladder pattern fragmentation of U937 cells after lectin-II stimulation. Obviously, lectin-II treatment of cells resulted in a remarkable generation of intracellular hydrogen peroxide (H2O2) as an early event, which was monitored fluorimetrically using scopoletin-horse radish peroxidase (HRP) assay and peroxide-sensitive fluorescent probe, DCF-DA. In addition, antioxidants inhibited the activation of c-Jun N-terminal kinase (JNK)/stress-activated protein kinase (SAPK) as well as cytosolic release of cytochrome c by mistletoe lectin-II. Moreover, lectin-II-induced activation of caspase-9 and 3-like protease and cleavage of poly(ADP-ribose) polymerase (PARP) were inhibited by pretreatment of cells with thiol antioxidants, GSH and NAC. Taken together, these results suggest that Korean mistletoe lectin-II is a strong inducer of pro-oxidant generation such as H2O2, which mediates the JNK/SAPK activation, cytochrome c release, activation of caspase-9 and caspase 3-like protease, and PARP cleavage in human myeloleukemic U937 cells.

Changes in suprarenal and infrarenal aortic angles after endovascular aneurysm repair.

PURPOSE: We investigated whether suprarenal and infrarenal aortic angles change after the endovascular aneurysm repair (EVAR) procedure and during follow-up, and investigated the correlation between infrarenal aortic angle after EVAR and type Ia endoleaks. METHODS: Data collected on 70 EVAR procedures for a fusiform infrarenal aortic aneurysm performed between May 2006 and December 2012 were supplemented with a retrospective review of charts and radiographs. RESULTS: The greater the preoperative infrarenal aortic angle, the greater the suprarenal aortic angle (r = 0.72, P < 0.001). The infrarenal aortic angle decreased after the EVAR procedure and continued to decrease slowly thereafter (all P < 0.001). Suprarenal aortic angle decreased immediately after the EVAR procedure and continued to decrease during the first month (P < 0.001). No differences in angulation were observed based on stent graft type. Type Ia endoleaks occurred with significantly greater incidence in patients with a larger post EVAR infrarenal angle (P = 0.037). CONCLUSION: The infrarenal aortic angle decreased significantly immediately after the EVAR procedure and continued to decrease slowly thereafter. Suprarenal aortic angle decreased immediately after the EVAR procedure and continued to decrease during the first month. We found a correlation between infrarenal and suprarenal aortic angle. Type Ia endoleaks occurred with greater incidence in patients with a larger infrarenal angle immediately after EVAR.

MicroRNA profiling of tacrolimus-stimulated Jurkat human T lympocytes.

PURPOSE: This study investigated the Jurkat T cell line expresses cytotoxicity when treated with different concentrations of FK506, and analyzed the expression pattern of microRNA when stimulated by FK506 using the microRNAs microarray, as well as the expression pattern of a gene that is related to the differentiation, activation and proliferation of T cells after being affected by the change of microRNAs. METHODS: To investigate the effects of FK506 on microRNA expression, we purified total RNA of Jurkat cells treated with 20 µM FK506 for 72 hours and used to analyze microRNA profiling by using Agilent's chip. RESULTS: These results demonstrated that treatment with FK506 markedly induced the down-regulation of 20 microRNAs as well as the up-regulation of 20 microRNAs in a time-dependent manner. The genes that down-regulated by FK506 include let-7a(*), miR-20a(*), and miR-487a. Otherwise miR-202, miR-485-5p, and miR-518c(*) are gradually up-regulated in expression. Sanger Institute and DAVIDs bioinformatics indicated that microRNAs regulated the several transcriptomes including nuclear factor of activated T cell-related, T cell receptor/interleukin-2 signaling, and Ca(2+)-calmodulin-dependent phosphatase calcineurin pathways. CONCLUSION: As a result of treating FK506 to a Jurkat cell line and running the microRNA microarray, it was found that FK506 not only took part in the suppression of T cell proliferation/activation by inhibiting calcineurin in Jurkat apoptosis, but also affected the microRNAs that are involved in the regulation of various signal transduction pathways.

Mycophenolic acid mediated mitochondrial membrane potential transition change lead to T lymphocyte apoptosis.

PURPOSE: This study demonstrated that apoptosis induced by mycophenolic acid (MPA) is mediated by mitochondrial membrane potential transition (MPT) changes in Jurkat cells. METHODS: Cell viability and MPT changes were measured by flow cytometry. Western blotting was performed to evaluate the expression of Bcl-2 family proteins, Bid, truncated Bid (tBid), cytochrome c, voltage dependent anion channel (VDAC), poly ADP-ribose polymerase (PARP), and protein kinase C-δ (PKC-δ). The catalytic activity of caspase-9 and -3 was also measured. RESULTS: Cell viability was decreased in time- and dose-dependent manners. Bcl-2 protein expression was decreased, but Bax protein expression was identified. A decreased Bcl-X(L) /Bcl-X(S) ratio was also noted. The expression of tBid protein also increased in a time-dependent manner in Jurkat cells treated with MPA. While normal MPT appeared as orange fluorescence, abnormal MPT corresponded to green fluorescence. Green fluorescence increased as orange decreased in the MPA-treated cells. Significantly increased concentrations of MPA induced the release of cytosolic cytochrome c. MPA also augmented the catalytic activity of caspase-9 and caspase-3 in Jurkat cells. Our findings demonstrated that MPA-induced apoptosis is mediated by MPT changes accompanied by decreased Bcl-XL expression and the appearance of tBid protein. The release of cytosolic cytochrome c from mitochondria and increased catalytic activity of caspase-9 and caspase-3 were observed in MPA-treated Jurkat cells. CONCLUSION: These results suggest that mitochondrial dysfunction caused by MPA induces human T lymphocyte apoptosis.

Cisplatin ototoxicity involves cytokines and STAT6 signaling network.

We herein investigated the role of the STAT signaling cascade in the production of pro-inflammatory cytokines and cisplatin ototoxicity. A significant hearing impairment caused by cisplatin injection was observed in Balb/c (wild type, WT) and STAT4(-/-), but not in STAT6(-/-) mice. Moreover, the expression levels of the protein and mRNA of pro-inflammatory cytokines, including TNF-α, IL-1ß, and IL-6, were markedly increased in the serum and cochlea of WT and STAT4(-/-), but not STAT6(-/-) mice. Organotypic culture revealed that the shape of stereocilia bundles and arrays of sensory hair cell layers in the organ of Corti from STAT6(-/-) mice were intact after treatment with cisplatin, whereas those from WT and STAT4(-/-) mice were highly distorted and disarrayed after the treatment. Cisplatin induced the phosphorylation of STAT6 in HEI-OC1 auditory cells, and the knockdown of STAT6 by STAT6-specific siRNA significantly protected HEI-OC1 auditory cells from cisplatin-induced cell death and inhibited pro-inflammatory cytokine production. We further demonstrated that IL-4 and IL-13 induced by cisplatin modulated the phosphorylation of STAT6 by binding with IL-4 receptor alpha and IL-13Rα1. These findings suggest that STAT6 signaling plays a pivotal role in cisplatin-mediated pro-inflammatory cytokine production and ototoxicity.

Perivascular epithelioid cell tumor (PEComa) of the ascending colon: the implication of IFN-α2b treatment.

A 7-year-old boy presented with hematochezia and abdominal pain. A 3.7-cm-sized mass was identified in the ascending colon by abdominal computed tomography and colonoscopy. The patient underwent surgical resection. Pathological examination revealed a low-grade perivascular epithelioid cell tumor (PEComa). PEComa in the colon is very rare. Only a few cases have been reported so far. An effective treatment method for this rare tumor has not been established yet. The patient received adjuvant interferon-α immunotherapy for 1 year. He has been tumor-free for 26 months since the initial diagnosis. This report is the first documented case of the use of interferon-α for pediatric PEComa of the colon.

All-trans retinoic acid inhibits the differentiation, maturation, and function of human monocyte-derived dendritic cells.

All-trans retinoic acid (ATRA) affects on the function of antigen presenting cells with somewhat controversies. We investigated the effects of ATRA on differentiation, maturation and function of human monocyte-derived dendritic cells (DCs). Low dose (10(-14)M) or high dose (10(-6)M) of ATRA was added either when monocytes were differentiated into immature DCs (imDCs) or mature DCs (mDCs) were induced. Apoptotic cell populations were dramatically increased in imDCs or mDCs with increasing concentration of ATRA. The productions of IL-12p40 and IL-12p70 were significantly suppressed in imDCs or mDCs induced by the addition of ATRA in the dose-dependent manner, whereas IL-10 was increased. DCs cultured with ATRA induced the differentiation of naïve T cells towards a helper T cell type 2 (Th2) response and expansion of CD4(+)CD25(+)Foxp3(+) regulatory T cells. Allostimulatory capacity of DCs was suppressed with increasing concentration of ATRA. These findings suggest that ATRA inhibits the effects on the differentiation, maturation and function of human monocyte-derived DCs in vitro and also enhance the differentiation of naïve T cell toward the Th2 type.

The dysfunction and abnormal signaling pathway of dendritic cells loaded by tumor antigen can be overcome by neutralizing VEGF in multiple myeloma.

We investigated whether dendritic cells (DCs) from multiple myeloma (MM) patients were affected by loading tumor antigens and whether the defective DC function associated with MM could be overcome by the neutralization of VEGF. MM-specific DCs were generated by loading tumor lysates from myeloma cells at diagnosis or relapsed/progressive state, respectively. DCs loaded with tumor lysates showed lower phenotypic maturation, less T cell stimulatory capacity, less cytotoxic T lymphocyte activities, and highly abnormal cytokine secretions of IL-6 and IL-12, compared to myeloma lysate-unloaded DCs. The levels of VEGF, phospho-STAT3 and phospho-ERK1/2 in DCs were significantly higher with loading myeloma lysates. After the neutralization of VEGF activity, the DC function, signal transduction and cytokine production returned to normal. The defective function of DC in patients with MM is significantly affected by loading tumor antigens, correlating with abnormal STAT3 and the NF-kappaB signaling pathway, and neutralization of VEGF can overcome this DC dysfunction through the elimination of abnormal signal transduction.

Ebselen attenuates cisplatin-induced ROS generation through Nrf2 activation in auditory cells.

Ebselen, an organoselenium compound that acts as a glutathione peroxidase mimetic, has been demonstrated to possess antioxidant and anti-inflammatory activities. However, the molecular mechanism underlying this effect is not fully understood in auditory cells. The purpose of the present study is to investigate the protective effect of ebselen against cisplatin-induced toxicity in HEI-OC1 auditory cells, organotypic cultures of cochlear explants from two-day postnatal rats (P(2)) and adult Balb/C mice. Pretreatment with ebselen ameliorated apoptotic death induced by cisplatin in HEI-OC1 cells and organotypic cultures of Corti's organ. Ebselen pretreatment also significantly suppressed cisplatin-induced increases in intracellular reactive oxygen species (ROS), intracellular reactive nitrogen species (RNS) and lipid peroxidation levels. Ebselen dose-dependently increased the expression level of an antioxidant response element (ARE)-luciferase reporter in HEI-OC1 cells through the translocation of Nrf2 into the nucleus. Furthermore, we found that pretreatment with ebselen significantly restored Nrf2 function, whereas it ameliorated the cytotoxicity of cisplatin in cells transfectants with either a pcDNA3.1 (control) or a DN-Nrf2 (dominant-negative) plasmid. We also observed that Nrf2 activation by ebselen increased the expression of phase II antioxidant genes, including heme oxygenase (HO-1), NAD(P)H:quinine oxidoreductase, and gamma-glutamylcysteine synthetase (gamma-GCS). Treatment with ebselen resulted in an increased expression of HO-1 and intranuclear Nrf2 in hair cells of organotypic cultured cochlea. After intraperitoneal injection with cisplatin, auditory brainstem responses (ABRs) threshold was measured on 8th day in Balb/C mice. ABR threshold shift was marked occurred in mice injected with cisplatin (16 mg/kg, n=5; Click and 8-kHz stimuli, p<0.05; 4, 16 and 32 kHz, p<0.01), whereas that of animal group which was treated with cisplatin and ebselen was not significantly changed. These results suggest that ebselen activates the Nrf2-ARE signaling pathway, which ultimately prevents free radical stresses from cisplatin and further contributes to protect auditory sensory hair cells from free radicals produced by cisplatin.