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Biomedical subjects

J A Ferraro

Publications and source records attributed to J A Ferraro.

30 records · Page 2Linked to original sources
PubMed1983

A randomized phase II study of m-AMSA (NSC 249992) and neocarzinostatin (NSC 157365) in non-small cell bronchogenic carcinoma. An Eastern Cooperative Group Study.

Eighty-nine patients with advanced non-small cell bronchogenic carcinoma were treated with either m-AMSA 120 mg/m2 intravenously every 3 weeks or neocarzinostatin 2.0 mg/m2 intravenously daily X 5 every 4 weeks. There were no responses in 40 evaluable patients who received m-AMSA and three partial responses (7.5%) in 40 patients who received neocarzinostatin. Two patients receiving m-AMSA had drug-related deaths. For m-AMSA the major toxicities were hematologic, while for neocarzinostatin the major toxicities were hematologic, gastrointestinal, and fever. We conclude that m-AMSA is inactive while neocarzinostatin has minimal activity in non-small cell bronchogenic carcinoma.

Aged↗
PubMed1983

Temporal summation in normally and abnormally hearing chinchillas.

Young adult monauralized chinchillas (N:5) were conditioned to cross a barrier in response to 7 pure tones from .5-4 kc/s. Tone bursts were either 20- or 500-msec long. Individual S's yielded threshold data for the longer duration comparable to published norms. Group mn difference between thresholds at 20- vs 500-msec durations [i.e., temporal summation (TS)] was 7 db, or 4.7 db less than TS reported for normal chinchillas reported by Wall et al (J. Aud. Res., 1981, 21, 29-37) and others. One S yielded no TS. After exposure for 4 hrs to a 2-kc/s tone at 120 db SPL, group mn thresholds for the 20-msec tones were only 1 db poorer than those for 500-msec tones (i.e., negligible TS). TS is clearly altered in noise-induced hearing loss.

Acoustic Stimulation↗
PubMed1981

Effects of prolonged noise exposure in chinchillas with severed middle ear muscles.

Using the round window-recorded cochlear microphonic as the index of acoustic reflex activity, we noted a decay in the strength of middle ear muscle contraction in the chinchilla following an eight hour exposure to octave band noise (500 Hz. center frequency, 95 dB. sound pressure level). On the basis of this observation it was concluded that the prolonged exposure reduced the effectiveness of the acoustic reflex in protecting the cochlea. This reduction, however, may have been underestimated if the exposure was also sufficient to reduce cochlear output. The present investigation examined this possibility by comparing the effects of a similar exposure in chinchillas with intact (normal) and severed middle ear muscles. Following exposure, the cochlear microphonic magnitude increased slightly in the normal group. Decreases in the cochlear microphonic were observed in the animals with severed muscles even when the overall exposure level was reduced to simulate the effects of middle ear muscle contraction. These findings indicate that although the muscles did afford some degree of protection to the cochlea during the exposure, the protective effects of the acoustic reflex may have been reduced even beyond our original observations.

Animals↗
PubMed1979

Reflex threshold shift in chinchillas following a prolonged exposure to noise.

The acoustic reflex is considered to reduce transmission across the middle ear and thereby protect the inner ear from intense sounds. The dynamic properties of this reflex seem to be a function of the duration of the eliciting stimulus. Assessment of the protective action afforded by middle-ear muscle contractions for long-term noise exposures requires the knowledge of how these dynamic properties change under such conditions. Round window electrodes were implanted in eight chinchillas. Changes in the threshold of the acoustic reflex were measured during an eight-hour exposure at 95 dB SPL to an octave-band noise centered at 0.5 kHz. The criterion measure of the acoustic reflex was a change in the amplitude of the cochlear microphonic generated by a 0.5 kHz eliciting tone. Thresholds of the acoustic reflex increased systematically throughout the noise exposure up to approximately 14 dB after 8 hours. The time course of the changes in the threshold of the acoustic reflex was nearly identical to the time course of behaviorally measured changes in the auditory sensitivity as reported by Carder and Miller (1972).

Acoustic Stimulation↗
PubMed1975

Electrolytic lesioning in the cochlea.

A method has been developed whereby relatively discrete protions of the organ of Corti can be selectively destroyed with the use of a high-frequency current. The procedure involves passing th current (1 to 3 ma at an approximate frequency of 5 megahertz) between a differential pair of recording electrodes located in the scalae vestibuli and tympani of a particular cochlear turn. Damage patterns progressing from partial to complete outer hair cell lesioning and eventually to the inner hair cells accompanied by progressive decreases in cochlear microphonic sensitivity can be effected.

Animals↗
PubMedDate not supplied

Acoustic reflex decay in chinchillas during a long-term exposure to noise.

Reflex decay to 0.5 kHz octave-band noise at 95 dB SPL was measured in chinchillas during four 2-hr exposure periods separated by 11-min quiet intervals. Round window electrodes were implanted in six animals. Measures of acoustic reflex decay were inferred from amplitude changes in the cochlear microphonic generated by the octave-band noise. Reflex decay followed essentially the same time course during each exposure period. Vigorous muscular contraction to the signal onset was followed by gradual decay that asymptoted between 30 and 50% of its initial value. The process of decay seemed to be complete sometime between 8 and 30 min. The results suggest that the middle ear muscles in chinchillas provide some protective function during exposures of fairly long duration.

Animals↗
PubMedDate not supplied

Comparison between AER and behavioral thresholds in normally and abnormally hearing chinchillas.

The present study compared the auditory evoked response (AER) and behavioral thresholds from the chinchilla before and after acoustic overstimulation. Bipolar electrodes were chronically implanted in the inferior colliculus of seven monauralized behaviorally conditioned animals (shock-avoidance). AER to 20-msec and behavioral thresholds to 20- and 500-msec tone bursts were determined for a range of frequencies before and after a 4-hour exposure to a 2000 Hz, 120dB SPL pure tone for six of the animals. One animal served as control and received no exposure. Results revealed a relatively close correspondence between AER and behavioral thresholds both before and after noise exposure in the same animal. Postexposure AER and behavioral thresholds displayed mild to moderate losses in sensitivity in the 1 to 4 kHz range. These findings justify further development of this particular AER as an indicator of hearing sensitivity in the chinchilla.

Animals↗
PubMedDate not supplied

Cochlear potentials in clinical audiology.

The recording of cochlear and auditory nerve potentials in humans via Electrocochleography (ECochG) has emerged as a valuable tool for a variety of clinical applications. This review consolidates current research on the use of cochlear potentials and ECochG in the clinical setting and identifies several areas in need of additional study. Methodological topics discussed include a review of ECochG recording approaches (i.e. transtympanic versus extratympanic) and issues related to choice of stimuli (clicks versus tonebursts). The review of current applications for cochlear potentials focuses primarily on the use of ECochG in the identification and treatment of Ménière's disease/endolymphatic hydrops (MD/ELH). Other uses for ECochG also are presented (e.g. intraoperative monitoring, enhancement of ABR wave I, estimation of hearing sensitivity). Several suggestions are offered to maximize the predictive value of ECochG in the diagnosis of MD/ELH.

Audiometry, Evoked Response↗
PubMedDate not supplied

Treatment of advanced colorectal carcinoma with AMSA.

AMSA in a dose of 120 mg/m2 iv every 4 weeks was evaluated in 26 patients with advanced measurable colorectal cancer, 13 of whom had had no prior chemotherapy. The schedule was tolerated well except by those patients who had prior irradiation or chemotherapy, in whom a dose reduction to 90 mg/m2 was required. No significant antitumor response was observed.

Adult↗