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Objectives/Hypothesis Cisplatin induces adverse effects such as ototoxicity and nephrotoxicity. Unexplained hearing improvement in sudden deafness and fluctuating hearing loss suggests the presence of some mechanisms other than the primary lesion of the outer hair cell. The authors' aim was to study the functional and morphological lesions induced in the cochlea of the rat after cisplatin injection. Study Design Prospective experimental morphological and functional study. Methods Forty-eight Wistar rats were given intraperitoneal injections of 5 mg/kg cisplatin. After short-, medium-, and long-term survival, animals were studied by means of auditory brainstem response testing and scanning electronic microscopy. Results An increased hearing loss was observed in animals with long-term survival compared with animals with short-term survival after a single dose of cisplatin. These findings correlated with a more intense injury of the supporting cells, continuing with the late deterioration of the hair cells. Conclusion The study suggested that the initial damage of the supporting cells could be responsible for the late injury of the hair cells. This hypothesis was supported by the late increase in hearing loss after a single dose of cisplatin, emphasizing the role of the supporting cells in the cochlear changes induced by cisplatin.

Resumen El cisplatino es un agente antitumoral empleado frecuentemente en el tratamiento de diversos tumores solidos. Es conocido que su uso induce efectos secundarios de ototoxicidad, ademas de nefrotoxicidad por fracaso renal agudo. Esta circunstancia lo hace el medicamento ideal a la hora de plantear un modelo experimental de ototoxicidad. El proposito de la presente investigacion es el estudio de los danos celulares provocados por diversas dosis de cisplatino inyectadas intraperitonealmente, con supervivencias variables en ratas y cobayas, analizados mediante microscopia electronica de barrido. Los resultados muestran la afectacion global de todas las estructuras constituyentes del organo de Corti, aunque con una afectacion inicial de las celulas de soporte, seguida por un posterior deterioro de las celulas sensoriales, contrariamente a lo descrito antes en la literatura.

The coherent inelastic response from liquid deuterium in three different thermodynamic states has been measured on a thermal three axis neutron spectrometer. The observed dispersive behaviour has been analyzed using a damped harmonic oscillator model. The momentum transfer dependencies of the renormalized frequencies and damping coefficients are compared and related to the results from correlated density matrix formalism.

Neutron inelastic triple-axis spectra of CD 3 OD/6%D 2 O in the glassy and liquid phases are reported. Both the dispersion and damping of the sound modes show characteristic features as the temperature is lowered to the glassy regime. Furthermore, analysis of the observed scattering intensities reveals the presence in the glass of a second component centred at zero frequency which is not observed in the liquid.

Well defined collective excitations up to a momentum transfer value of 3.8 A -1 have been found in liquid deuterium 0.5 K above the melting point. The derived dispersion curve shows a remarkable similarity with the one observed for liquid 4 He in the normal liquid phase, with a well defined minimum at a momentum transfer of 2.08 A -1 corresponding to a gap of 30 K. A qualitative comparison is made with recent calculations on liquid para-hydrogen at the triple point.

Neutron inelastic triple-axis spectra of CD 3 OD/6% D 2 O in the glassy and liquid phases are reported. Both the dispersion and damping of the sound modes show characteristic features as the temperature is lowered down into the glassy regime. Also the analysis of the observed scattering intensities evidences the presence in the glass of a second component centered at zero frequency which is not observed in the liquid.

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.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.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.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%.

Cisplatin is an antitumoral agent commonly used in the treatment of different solid tumors. Its use induces adverse effects like oto- and nephrotoxicity due to acute renal failure. This makes it a suitable drug when creating an experimental model of ototoxicity. Our aim is to study the cellular lesions induced in the cochlea of the rat and the guinea pig by variable doses of cisplatin injected intraperitoneally, after short, middle, and long term survival, by means of scanning electronic microscopy. Results show the global effect of the cells of the organ of Corti with a more intense initial damage of the supporting cells, continuing with the late effect of the sensorial cells.

The coherent dynamical response of liquid deuterium 0.5 K above the melting temperature has been studied by means of triple-axis inelastic scattering and time-of-flight techniques. A model scattering law to represent the single-particle and low energy collective dynamics has been tested by analysing the time-of-flight spectra. On the other hand, well defined collective excitations up to a momentum transfer of 3.8A-1 have been found in the triple-axis experiments. The derived dispersion curve shows a well defined minimum at 2.08A-1 with a gap of 30 K.

16 págs.; 13 figs., The collective dynamics of liquid deuterium is studied by means of inelastic neutron scattering (INS) at 20.14 K and under 2 bars of applied pressure using two different incident energies. The low-incident-energy (high-energy-resolution) spectra are studied in detail by means of a time-of-flight (TOF) technique, whereas the finite-frequency response is investigated using a higher incident energy on a triple-axis spectrometer (TAS). The main finding of our work is the observation by the latter experimental technique of well-defined collective excitations up to a momentum transfer of 3.8 A-1. Comparisons are established with the dispersive behavior observed in other liquid systems as well as with the predictions from recent correlated-density-matrix calculations. © 1993 The American Physical Society., This work has been supported in part by DGICYT Grant No. PB89-0037-C03 and by the Deutsche Forschungsgemeinschaft under Grant No. Ri 267/16-1.

En el presente trabajo se realiza un estudio de las excitaciones colectivas de longitud de onda comparables al espaciado intermolecular y que tienen lugar en tres sistemas con potenciales intermoleculares distintos: un vidrio molecular (metanol deuterado), un liquido polar (dioxido de azufre) y un liquido con aspectos cuánticos (deuterio). El estudio se ha realizado mediante espectroscopia neutrónica. En el caso del metanol se han encontrado excitaciones de carácter armónico de alta frecuencia, las cuales coexisten con otras de baja frecuencia, posibles responsables de las anomalias observadas en los vidrios. En el liquido polar se han observado excitaciones colectivas propagativas que entran rápidamente en un régimen sobreamortiguado, presentando ciertas anomalias. Por primera vez se ha obtenido la curva de dispersión del deuterio, siendo muy parecida a la del helio 4 liquido pero con una dispersión positiva mucho mayor, concretamente de un 29%.