Heat shock protein 70 and cellular disturbances in cochlear cisplatin ototoxicity model.

BACKGROUND: Exposure to cisplatin leads to cochlear cell death by apoptosis; these changes are most marked on the seventh day after exposure. Heat shock proteins are induced in inner ear cells in response to a variety of stimuli. This study examined the role of heat shock protein 70 in cisplatin-induced cochlear cell death. METHODS: Fifty-six Sprague-Dawley rats were involved. Some were injected with cisplatin (5 mg/kg body weight), some with cisplatin plus the caspase inhibitor Z-Asp(OMe)-Glu(OMe)-Val-Asp(OME)-fluoromethylketone (5 mg/kg body weight) and others were left as controls (being injected only with saline). Seven days later, we examined the expression of heat shock protein 70 and several other apoptosis-related proteins within the rat cochlear cells; we also assessed total superoxide dismutase activity, auditory brainstem response and auditory steady state response. RESULTS: Seven days after cisplatin injection, significantly increased expression of heat shock protein 70 was found within the rat cochleae. This correlated with increased executioner caspase levels, total superoxide dismutase activity and auditory brainstem response thresholds, and a significant elevation in auditory steady state response thresholds. Inhibition of caspase-3 activity significantly reduced cochlear heat shock protein 70 expression and total superoxide dismutase activity, and improved auditory brainstem response and auditory steady state response thresholds. CONCLUSIONS: Seven days after cisplatin exposure, we found disturbances of the cochlear cellular machinery involving heat shock protein 70, other apoptotic proteins and total superoxide dismutase.

The anticancer drug cisplatin induces an intrinsic apoptotic pathway inside the inner ear.

BACKGROUND AND PURPOSE: Ototoxicity is a known adverse effect of cisplatin (CDDP). Since apoptosis is involved in the development of some pathological conditions associated with the administration of anticancer drugs, we examined, using immunohistochemical and electrophysiological techniques, the apoptotic changes in the cochlea of Sprague-Dawley (SD) rats after an injection of CDDP (5 mgkg(-1) body weight). EXPERIMENTAL APPROACH: Luciferase assays were used to determine the different caspase activities and ATP levels in protein extracts of whole cochleae. The expression of several apoptotic-related proteins was measured by means of Western blotting. These analyses were performed 2, 7 and 30 days after the CDDP injection. The auditory brain stem response was obtained before and at the different times after the injection of CDDP, before the animals were killed. KEY RESULTS: CDDP significantly increased the levels of caspase-3/7 activity and active caspase-3 protein expression and caspase-3 immunofluorescence staining, caspase-9 activity, and Bax protein expression but decreased Bcl-2 protein expression within the rat cochleae. Threshold shifts were significantly elevated 2 days after CDDP treatment. CONCLUSIONS AND IMPLICATIONS: These findings support the hypothesis that cisplatin-related apoptosis evokes an intrinsic pathway of pro-apoptotic signalling within the rat cochleae. Thus, selective inhibition of the sequence of events involved in the intrinsic apoptotic pathway could provide a strategy to minimize cisplatin-induced ototoxicity.

HSP-70 as a nonspecific early marker in cisplatin ototoxicity.

CONCLUSION: The great variety of pathological entities related to the presence of circulating HSP-70 suggests a nonspecific cellular damage. As the present study shows, positive results decrease with respect to the time elapsed after the injection of the ototoxic agent. HSP-70 appears as an early and transient marker that could permit early detection of inner ear damage. OBJECTIVES: The aim of this study was to determine the presence of HSP-70 at different time points by means of Western blot immunoassay in the sera of rats treated with cisplatin. MATERIALS AND METHODS: Thirty-six Wistar rats were intraperitoneally injected with cisplatin at a dose of 5 mg/kg and blood samples were collected at 7 and 90 days. Determination of HSP-70 was made by means of a modified Western blot immunoassay kit originally used for human HSP-70 antigen detection. A control group of 18 animals was used for comparison. RESULTS: Western blot was positive in 77.8% of the animals in the 7 days group, decreasing to a 44.4% in the 90 days group. In the control group, Western blot was positive in 5.5%.

Endonasal endoscopic management of a large meningocephalocele in a patient with concomitant middle skull base defect.

The presence of a skull base defect can lead to major complications such as cerebrospinal fluid leak, meningocele, encephalocele and meningitis. It is exceptional to find the existence of two concomitant defects in the skull base. We present the case of a patient with concomitant spontaneous defects of the anterior and middle skull base that were surgically repaired. After 18 years of right rhinorrhea the patient was referred after being diagnosed with a large right nasal fossa meningoencephalocele, which was surgically removed by functional endoscopic sinus surgery. Following the surgery the patient complained about unilateral ear fullness. A paracentesis revealed a highly suspicious cerebrospinal fluid collection. High resolution scans revealed a defect in the mastoid tegmen; subsequently a transmastoid approach was carried out. Greater defects or those lying around the internal auditory canal, are best treated via the middle fossa approach. In the anterior cranial fossa the treatment of choice is provided by endoscopic procedures, but frontal bone craniotomy should be considered if the defect is in the frontal sinus or greater than 5 cm in size.

[Treatment of early glottic carcinoma with transoral laser CO2]. / Tratamiento del cáncer glótico precoz con cirugía transoral láser CO2.

OBJECTIVE: We present our outcome in the treatment of 125 patients with malignant glottic lesions between 1992 and 2003 in a retrospective study. PATIENT AND METHODS: We analyze 125 cases of patients, with previously untreated carcinoma of the larynx with histological diagnosis, treated with Transoral Laser Microresection. We will pay special attention to those tumors involving the Anterior Commissure. We will also analyze several parameters related to the post and intraoperatory histopathological report, in order to decide adjuvant therapies. We will also analyze the technique indications, complications, hospital length of stay, oncologic and functional outcomes, survival and follow up of recurrences. OUTCOMES AND CONCLUSION: Transoral laser microresection is an effective and functional preserving procedure, and nowadays the base of the treatment of early glottic carcinoma. Anterior Commissure involvement is a prognostic factor. Sometimes complementary therapies are needed based on by the histopathological report.

[Temporal bone chondroblastoma. A clinical case and literature review]. / Condroblastoma de hueso temporal. Caso clínico y revisión de la literatura.

We report a clinical case of a 31 year old male with a left temporal painful mass of six months evolution. After radiologic diagnosis, intraoperatory biopsy and surgical removal, the anatomopathological result confirmed the histology of chondroblatoma, with a satisfactory postoperative evolution. The chondroblastoma is a benign bone tumor typically located in the epiphysis of long bones and the temporal bone is an excepcional location as we have verified through a literature review.

Central role of supporting cells in cochlear homeostasis and pathology.

HYPOTHESIS: Supporting cells have a crucial role in degenerative and regenerative events of primary sensorial hair cells of the organ of Corti. This new role should determine future studies about pathophysiology of hearing loss and its regenerative treatment. SUPPORTING EVIDENCE: Recent findings suggest an active role of supporting cells in the maintenance of hair cell function and structure. Evidences of high energy consumption and close proximity to auditory nervous fibers suggesting K+ active exchange, preferential expression of specific proteins and antigens, presence of glucocorticoids receptors, affinity for cisplatin and regenerative potential give the supporting cells an important role in homeostasis of the organ of Corti and in some specific diseases affecting this structure. CONCLUSION: As well as glial cells provide protection and regeneration to neural tissues, supporting cells may provide the necessary metabolic and electrolitic conditions for hair cells mechanical and bioelectrical function. This opens new possibilities for the treatment of apparently "irreversible" destruction of the inner ear.

[Cancer of the parotid gland]. / Tumores malignos de la glándula parótida.

OBJECTIVE: To review our experience and results in the diagnosis and treatment of a low incidence pathology such as the cancer of the parotid gland. METHODS: The study reviewed 40 patients with malignant tumors of the parotid gland treated between 1991 and 2002 in our hospital. It was used the staging system TNM (American Joint Committee on Cancer 1997). RESULTS: The most common histological type in our series is the squamous cell carcinoma, in general unilateral and in the superficial lobe. Rapid tumor enlargement, fixation to the skin, cervical lymphadenopathy, pain and facial palsy are malignancy clinical findings. We obtained a 56% 5-year global survival rate, with a 68% for stages I and II, and 43% for stages III and IV. CONCLUSIONS: This pathology has a low incidence but high mortality. The staging and histological type are important prognostic factors. The surgery is the election treatment, associated with neck disection or radiotherapy.

[Geniculate ganglion tumors. Therapeutic and reconstructive management]. / Tumores del ganglio geniculado. Manejo terapéutico y reconstructivo.

We present five cases of patients diagnosed of a facial nerve tumoral lesion localised at the Geniculate Ganglion and all of which underwent surgical resection. The initial symptoms were in four cases of peripheral facial nerve paralysis and in the fifth case facial paresis. Two trans-mastoid extralabyrinthine approaches were performed and one through a combined path (middle fossa and trans-mastoid) with reconstruction of the facial nerve through a termino-terminal graft. In the fourth case, an approach through fossa media was done, and did not include nerve reconstruction but palliative treatment with a palpebral gold plaque. In the fifth case, a modified trans-labyrinthine approach with facial-hypoglossus termino-terminal anastomosis. Histological diagnosis was 3 neurinomas and 2 hemangiomas. Of the termino-terminal grafts two managed a functional Grade III of the House-Brackmann classification. The third one sustained a Grade VI and therefore a suspension with temporal muscle was carried out. The patient with facial-hypoglossus anastomosis is in a functional Grade IV. Geniculate ganglion tumors are in their majority benign and their treatment is the total resection of the tumor. Nerve reconstruction can be primary or deferred with the aid of a nerve graft or anastomosis, being necessary palliative techniques when resection is not possible.

Phenol derivatives as enhancers and inhibitors of luminol-H2O2-horseradish peroxidase chemiluminescence.

Systematic studies on phenol derivatives facilitates an explanation of the enhancement or inhibition of the luminol-H2O2-horseradish peroxidase system chemiluminescence. Factors that govern the enhancement are the one-electron reduction potentials of the phenoxy radicals (PhO./PhOH) vs. luminol radicals (L./LH-) and the reaction rates of the phenol derivatives with the compounds of horseradish peroxidase (HRP-I and HRP-II). Only compounds with radicals with a similar or greater reduction potential than luminol at pH 8.5 (0.8V) can act as enhancers. Radicals with reduction potentials lower than luminol behave in a different way, because they destroy luminol radicals and inhibit chemiluminescence. The relations between the reduction potential, reaction rates and the Hammett constant of the substituent in a phenol suggest that 4-substituted phenols with Hammett constants (sigma) for their substituents similar or greater than 0.20 are enhancers of the luminol-H2O2-horseradish peroxidase chemiluminescence. In contrast, those phenols substituted in position 4 for substituents with Hammett constants (sigma) lower than 0.20 are inhibitors of chemiluminescence. On the basis of these studies, the structure of possible new enhancers was predicted.

Enhancer effect of fluorescein on the luminol-H2O2-horseradish peroxidase chemiluminescence: energy transfer process.

The chemiluminescence of the luminol-H2O2-horseradish peroxidase system is increased by fluorescein. Fluorescein produces an enhancement of the luminol chemiluminescence similar to that of phenolphthalein, by an energy transfer process from luminol to fluorescein. The maximum intensity and the total chemiluminescence emission (between 380 and 580 nm) of luminol with fluorescein was more than three times greater than without fluorescein; however, the emission duration was shorter. The emission spectra in the presence of fluorescein had two maxima (425 and 535 nm) and the enhancement was dependent on pH and fluorescein concentration. A mechanism is proposed to explain these effects.

Assay of cholinesterase using a pro-enhancer of the luminol-H2O2-horseradish peroxidase reaction.

2-Naphthyl acetate acts as a pro-enhancer of the luminol-H2O2-horseradish peroxidase reaction. Cholinesterase hydrolyses the bound acetyl group and produces 2-naphthol, and this compound is an enhancer of the chemiluminescent reaction. We studied the kinetics of chemiluminescent emission and the influence of 2-naphthyl acetate and cholinesterase enzyme concentrations. The cholinesterase concentration versus chemiluminescence intensity maximum was linear for cholinesterase between 0 and 181 microU/mL, with a detection limit of 8 microU/mL and a relative standard deviation of 9.5% (n = 3), for a sample containing 90.67 microU/mL of cholinesterase.

Enhancement and inhibition of luminol chemiluminescence by phenolic acids.

We explored the behaviour of a series of phenolic acids used as enhancers or inhibitors of luminol chemiluminescence by three different methods to determine if behaviour was associated with phenolic acid structure and redox character. All the phenolic acids inhibited chemiluminescence when hexacyanoferrate (III) was reacted with the phenolic acids before adding luminol. The redox character of these compounds was clearly related to structure. When hexacyanoferrate(III)-luminol-O2 chemiluminescence was initiated by phenolic acid-luminol mixtures some phenolic acids behaved as enhancers of chemiluminescence, and others as inhibitors. We propose a mechanism to explain these findings. We found direct relationships between the redox character of the phenolic acids and the enhancement or inhibition of the chemiluminescence of the luminol-H2O2-peroxidase system and we propose mechanism to explain these phenomena.