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Biomedical subjects

R E Hooper

Publications and source records attributed to R E Hooper.

10 recordsLinked to original sources
PubMed1994

Absence of toxicity in patients with malignant otitis externa following long-term treatment with high dosage tobramycin.

An in-vitro model of aminoglycoside dosing was used to demonstrate that the bactericidal activity of tobramycin against Pseudomonas aeruginosa is directly related to the peak concentration of the drug. In addition, six patients who were being treated for malignant otitis externa with long-term, high dosage tobramycin were monitored for oto- and nephro-toxicity; the only adverse effects were transient increases in the serum creatinine concentration in two patients.

Aged↗
PubMed1991

Dosage adjustment and clinical outcomes of long-term use of high-dose tobramycin in adult cystic fibrosis patients.

A two-phase study was undertaken designed to investigate the impact of computer-aided drug monitoring on tobramycin concentrations and clinical outcomes in adult patients with cystic fibrosis. In phase one, a baseline (historical control) study of drug use patterns was performed. During the second phase, patients admitted for intravenous treatment with tobramycin for acute exacerbations of pseudomonal pulmonary infections were randomly allocated to one of two schedules. Group A patients had tobramycin dosage regimens decided by clinicians based on pre-existing protocols using serum tobramycin assay data determined three times weekly. Group B patients had dosage regimens determined by a computerized pharmacokinetic predictive program using both population-based pharmacokinetic parameter estimation and fitting of serum concentration-time data using Bayesian regression. The agreed therapeutic target was a peak serum tobramycin concentration of 8-10 mg/L and a trough concentration of 1-2 mg/L. There was a major difference between the two groups comparing the number of paired trough and peak concentrations within the target concentration ranges (group A-14%; group B-34.7%, chi 2 test, P less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Sinusoidal harmonic acceleration testing in normal humans.

Forty-one normal humans were tested with sinusoidal harmonic acceleration. Phase lag at 0.01, 0.02, and 0.04 Hz was the most stable parameter, with less test-retest variability than gain and asymmetry. There was no significant difference between men and women for phase lag, gain, or asymmetry at any of the five testing frequencies. Gain decreased as age increased. Age had no effect on phase lag at most test frequencies or on asymmetry at any frequency.

Acceleration↗
PubMed1977

Electrocochleographic response patterns in a group of patients mainly with presbyacusis.

The latency, amplitude and wave-form of the action potential were studied in a group of patients, mainly presbyacusics and a few with noise-induced hearing loss, sensorineural hearing loss of unknown etiology and conductive loss. Electrocochleographic recruitment with short latency of the AP "threshold" and very rapid increase in amplitude with increasing click intensity was seen in 22%. Partial recruitment with long latency at AP "threshold" but steep amplitude-intensity curves was present in 33%. Only 17% of the subjects showed both electrocpchleographic recruitment (or partial recruitment) and recruitment in the acoustic reflex test. Subjects with conductive loss had normal amplitude and latency intensity curves but they were shifted to the right. The action potential wave-form was normal. Broad action potentials with multiple peaks were the most common in sensorineural hearing loss.

Action Potentials↗
PubMed1977

Electrocochleography: a comparison of action potential and behavioral thresholds.

Using the technique of electrocochleography with transtympanic electrode placement, it is possible to estimate behavioral thresholds from AP data for a acoustic stimulus. The correlation between behavioril and AP "thresholds" for the same stimulus was statistically significant and there was a better correlation for subjects with a mild hearing loss than for those with normal hearing or larger degrees of hearing loss (as determined by the pure tone average). Larger amplitudes of the AP at the maximum stimulus level tended to be associated with a more accurate threshold estimation. The AP "thresholds" showed best correlation with the pure tone audiometric thresholds at 1 000 Hz, at other tone frequencies the correlation was poorer. This agrees with the spectral contents of the click.

Action Potentials↗
PubMed1976

Hereditary deafness and sensory radicular neuropathy.

We report a case of radicular sensory neuropathy and deafness. The patients appears to be one of a family in whom several members were similarly afflicted. Thus, this case fits the pattern of hereditary deafness and sensory radicular neuropathy, originally described by Hicks in 1922.

Adult↗
PubMedDate not supplied

Test-retest reliability in clinical electrocochleography.

The intratest test-retest reliability in clinical electrocochleography was studied by measuring the difference between amplitude of the test and retest and latency of the test and retest. Eighty-four comparisons were made in 40 patients with different types of hearing losses. The type of hearing loss and whether test and retest were performed in sequence or not did not affect the variability of the amplitude. The test and retest correlation between amplitudes was good. Small amplitudes mainly found near the action potential (AP) "threshold" showed less absolute variability than larger amplitudes found at higher intensities. The correlation between the intratest latencies was excellent. The latency showed less variability at higher intensities than near AP "threshold".

Action Potentials↗