John D. McLaren

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The availability of genetic information, transgenic and knock-out animals make the mouse a primary model in biomedical research. Aminoglycoside ototoxicity, however, has rarely been studied in mature mice because they are considered highly resistant to the drugs. This study presents models for kanamycin ototoxicity in adult CBA/J, C57BL/6 and BALB/c mouse(More)
Glutathione and glutathione-related enzymes protect against oxidative (free radical) cell injury. This study presents basic information on this antioxidant system in inner ear tissues and preliminary results of the influence of age, ototoxic drugs and noise. These conditions affect inner ear function, possibly through free radicals, and are therefore(More)
The formal characterization of the performance of microfluidic delivery devices is crucial for reliable in vivo application. A comprehensive laboratory technique was developed and used to optimize, calibrate and validate microfabricated fluid delivery devices. In vivo experiments were carried out to verify the accuracy and reliability of the pressure driven(More)
Microdialysis techniques were used to measure in vivo release of neuroactive amino acids from the central nucleus of the inferior colliculus (ICC) in anesthetized guinea pigs. Concentric dialysis probes were implanted in the ICC and perfused with Ringer solution of various compositions at a flow rate of 2.0 microliters/min. Consecutive 10-min fractions of(More)
We have demonstrated recently that incubation of the aminoglycoside gentamicin with an hepatic post-mitochondrial fraction produces a compound toxic to sensory cells from the inner ear in short-term culture; in contrast, the parent aminoglycoside was non-toxic in vitro (Huang MY and Schacht J, Biochem Pharmacol 40: R11-R14, 1990). In the present study, we(More)
This study demonstrates that cisplatin ototoxicity depends on dietary factors and correlates with decreased levels of cochlear glutathione and serum albumin. After 12 days of injections, cisplatin (1 mg/kg body weight, s.c.) caused a small hearing loss in guinea pigs fed a regular, full-protein diet (9 +/- 6 dB at 8 kHz and 10 +/- 9 dB at 18 kHz) but a(More)
This study demonstrates that gentamicin ototoxicity depends on dietary factors and correlates with tissue glutathione levels. After 15 days of gentamicin injections (100 mg/kg/day s.c.) guinea pigs on a regular protein diet (18.5% protein) had an average hearing loss of 9 dB at 3 kHz, 31 dB at 8 kHz and 42 dB at 18 kHz. Guinea pigs on a 7% protein diet(More)
The release of endogenous glutamate and other primary amines from the lateral-line of Xenopus laevis was studied using an in vitro superfusion technique and high performance liquid chromatography. Potassium stimulation (50 mM KCl) applied to 60 or 120 lateral-line organs dissected from the skin and pooled in a perfusion chamber induced the release of(More)
STATEMENT OF PROBLEM Few studies have been conducted to determine a correlation between the flexural modulus of metal and fiber-reinforced posts and the fracture resistance and failure mode of teeth restored with posts. Questions remain as to whether a longer post length or a post with a higher flexural modulus will significantly improve the fracture(More)
Following chemical mutagenesis and multiple-step indirect selection, four clones of Chinese hamster V79 cells were isolated which exhibited auxotrophy for thymidine, deoxycytidine, or deoxyuridine but not for cytidine or uridine. All were resistant to uridine, 3-deazauridine, 5-fluorouridine, thymidine, and cytosine arabinoside at concentrations that were(More)